Molecular defects of the growth hormone receptor gene, including a new mutation, in Laron syndrome patients in Israel: relationship between defects and ethnic groups.

Science.gov (United States)

Shevah, Orit; Rubinstein, Menachem; Laron, Zvi

2004-10-01

Laron Syndrome, first described in Israel, is a form of dwarfism similar to isolated growth hormone deficiency caused by molecular defects in the GH receptor gene. To characterize the molecular defects of the GH-R in Laron syndrome patients followed in our clinic. Of the 63 patients in the cohort, we investigated 31 patients and 32 relatives belonging to several ethnic origins. Molecular analysis of the GH-R gene was performed using the single strand conformation polymorphism and DNA sequencing techniques. Eleven molecular defects including a novel mutation were found. Twenty-two patients carried mutations in the extracellular domain, one in the transmembrane domain, and 3 siblings with typical Laron syndrome presented a normal GH-R. Of interest are, on one hand, different mutations within the same ethnic groups: W-15X and 5, 6 exon deletion in Jewish-Iraqis, and E180 splice and 5, 6 exon deletion in Jewish-Moroccans; and on the other hand, identical findings in patients from distinct regions: the 785-1 G to T mutation in an Israeli-Druze and a Peruvian patient. A polymorphism in exon 6, Gly168Gly, was found in 15 probands. One typical Laron patient from Greece was heterozygous for R43X in exon 4 and heterozygous for Gly168Gly. In addition, a novel mutation in exon 5: substitution of T to G replacing tyrosine 86 for aspartic acid (Y86D) is described. This study demonstrates: a) an increased focal incidence of Laron syndrome in different ethnic groups from our area with a high incidence of consanguinity; and b) a relationship between molecular defects of the GH-R, ethnic group and geographic area.

Dirichlet topological defects

International Nuclear Information System (INIS)

Carroll, S.M.; Trodden, M.

1998-01-01

We propose a class of field theories featuring solitonic solutions in which topological defects can end when they intersect other defects of equal or higher dimensionality. Such configurations may be termed open-quotes Dirichlet topological defects,close quotes in analogy with the D-branes of string theory. Our discussion focuses on defects in scalar field theories with either gauge or global symmetries, in 3+1 dimensions; the types of defects considered include walls ending on walls, strings on walls, and strings on strings. copyright 1998 The American Physical Society

Defects in semiconductors

CERN Document Server

Romano, Lucia; Jagadish, Chennupati

2015-01-01

This volume, number 91 in the Semiconductor and Semimetals series, focuses on defects in semiconductors. Defects in semiconductors help to explain several phenomena, from diffusion to getter, and to draw theories on materials' behavior in response to electrical or mechanical fields. The volume includes chapters focusing specifically on electron and proton irradiation of silicon, point defects in zinc oxide and gallium nitride, ion implantation defects and shallow junctions in silicon and germanium, and much more. It will help support students and scientists in their experimental and theoret

Sporophyte morphology and gametophyte development of the fern Blechnum sprucei (Pteridophyta: Blechnaceae

Directory of Open Access Journals (Sweden)

Jose María Gabriel y Galán

2008-12-01

Full Text Available The fern Blechnum sprucei grows in Mesoamerica (Costa Rica and South America, from Colombia to Bolivia, SE and centre of Brazil, Paraguay and Argentina. It is a distinctive, somewhat vulnerable, mostly orophilous species. Fresh and dry herbarium material was used for this study. Herbarium material for anatomical studies comes from CTES, BA, LP, MA, SI and UC (Holmgren et al.1990. Selected representative specimens are additionally cited after taxonomic treatment of the species. Dry material was restored with aqueous 4:1 butil cellosolve. Pinnae were cleared with aqueous 6% NaOH, then coloured with aqueous 1 % TBO (Gurr 1966. Hand made transverse sections of young and adult stipes, and costae were done in fresh and restored herbarium material. Venation and epidermal patterns were analyzed in basal, apical and medium pinnae, but only the latter were illustrated. The size and density of stomata were measured in medium pinnae from all studied samples, values shown are the average of 25 measures per sample; sizes are expressed as minimum, media and maximum length x width, in µm, and density as minimum, media and maximum number of stomata / mm². Spores were studied with SEM, mounted on metal stubs with double sided tape, covered with gold under vacuum and photographed with a Jeol /EO JSM 6360 (15 KV SEM. Spores were also studied with light microscope, mounted in DePex (DePex mounting medium, Gurr, BDH Laboratory Supplies, Poole BH15 1TD, UK and measured using an ocular micrometer. Measurements are based on a minimum sample of 100 spores taken from different specimens. Sizes are expressed as the longest equatorial diameter/ polar diameter, in µm. Gametophytes were studied from material collected in the subtropical forest of Tucumán Province, Argentina. Spore samples for cultures were taken from single sporophytes kept dry at room temperature since the date plants were collected. Gametophytes were grown under fluorescent light. Multispore cultures

Defect of the Eyelids.

Science.gov (United States)

Lu, Guanning Nina; Pelton, Ron W; Humphrey, Clinton D; Kriet, John David

2017-08-01

Eyelid defects disrupt the complex natural form and function of the eyelids and present a surgical challenge. Detailed knowledge of eyelid anatomy is essential in evaluating a defect and composing a reconstructive plan. Numerous reconstructive techniques have been described, including primary closure, grafting, and a variety of local flaps. This article describes an updated reconstructive ladder for eyelid defects that can be used in various permutations to solve most eyelid defects. Copyright © 2017 Elsevier Inc. All rights reserved.

Defect forces, defect couples and path integrals in fracture mechanics

International Nuclear Information System (INIS)

Roche, R.L.

1979-07-01

In this work, it is shown that the path integrals can be introduced without any reference to the material behavior. The method is based on the definition in a continuous medium of a set of vectors and couples having the dimension of a force or a moment. More precisely, definitions are given of volume defect forces, surface defect forces, volume defect couples, and surface defect couples. This is done with the help of the stress working variation of a particule moving through the solid. The most important result is: the resultant of all the defect forces included in a volume V is the J integral on the surface surrounding V and the moment resultant is the L integral. So these integrals are defined without any assumption on the material constitutive equation. Another result is the material form of the virtual work principle - defect forces are acting like conventional forces in the conventional principles of virtual work. This lead to the introduction of the energy momentum tensor and of the associated couple stress. Application of this method is made to fracture mechanics in studying the defect forces distribution around a crack [fr

Platelet rich fibrin in jaw defects

Science.gov (United States)

Nica, Diana; Ianes, Emilia; Pricop, Marius

2016-03-01

Platelet rich fibrin (PRF) is a tissue product of autologous origin abundant in growth factors, widely used in regenerative procedures. Aim of the study: Evaluation of the regenerative effect of PRF added in the bony defects (after tooth removal or after cystectomy) Material and methods: The comparative nonrandomized study included 22 patients divided into 2 groups. The first group (the test group) included 10 patients where the bony defects were treated without any harvesting material. The second group included 12 patients where the bony defects were filled with PRF. The bony defect design was not critical, with one to two walls missing. After the surgeries, a close clinically monitoring was carried out. The selected cases were investigated using both cone beam computer tomography (CBCT) and radiographic techniques after 10 weeks postoperatively. Results: Faster bone regeneration was observed in the bony defects filled with PRF comparing with the not grafted bony defects. Conclusions: PRF added in the bony defects accelerates the bone regeneration. This simplifies the surgical procedures and decreases the economic costs.

Defect production in ceramics

Energy Technology Data Exchange (ETDEWEB)

Zinkle, S.J. [Oak Ridge National Lab., TN (United States); Kinoshita, C. [Kyushu Univ. (Japan)

1997-08-01

A review is given of several important defect production and accumulation parameters for irradiated ceramics. Materials covered in this review include alumina, magnesia, spinel silicon carbide, silicon nitride, aluminum nitride and diamond. Whereas threshold displacement energies for many ceramics are known within a reasonable level of uncertainty (with notable exceptions being AIN and Si{sub 3}N{sub 4}), relatively little information exists on the equally important parameters of surviving defect fraction (defect production efficiency) and point defect migration energies for most ceramics. Very little fundamental displacement damage information is available for nitride ceramics. The role of subthreshold irradiation on defect migration and microstructural evolution is also briefly discussed.

Interploidal hybridization and mating patterns in the Sphagnum subsecundum complex.

Science.gov (United States)

Ricca, M; Szövényi, P; Temsch, E M; Johnson, M G; Shaw, A J

2011-08-01

Polyploidization is thought to result in instant sympatric speciation, but several cases of hybrid zones between one of the parental species and its polyploid derivative have been documented. Previous work showed that diploid Sphagnum lescurii is an allopolyploid derived from the haploids S. lescurii (maternal progenitor) and S. subsecundum (paternal progenitor). Here, we report the results from analyses of a population where allodiploid and haploid S. lescurii co-occur and produce sporophytes. We tested (i) whether haploids and diploids form hybrid triploid sporophytes; (ii) how hybrid and nonhybrid sporophytes compare in fitness; (iii) whether hybrid sporophytes form viable spores; (iv) the ploidy of any viable gametophyte offspring from hybrid sporophytes; (v) the relative viability of sporelings derived from hybrid and nonhybrid sporophytes; and (vi) if interploidal hybridization results in introgression between the allopolyploid and its haploid progenitor. We found that triploid hybrid sporophytes do occur and are larger than nonhybrid sporophytes, but exhibit very low germination percentages and produce sporelings that develop more slowly than those from nonhybrid sporophytes. All sporophytes attached to haploid gametophytes were triploid and were sired by diploid males, but all sporophytes attached to diploid gametophytes were tetraploid. This asymmetric pattern of interploidal hybridization is related to an absence of haploid male gametophytes in the population. Surprisingly, all sporelings from triploid sporophytes were triploid, yet were genetically variable, suggesting some form of aberrant meiosis that warrants further study. There was limited (but some) evidence of introgression between allodiploid and haploid S. lescurii. © 2011 Blackwell Publishing Ltd.

Dosage-sensitive function of retinoblastoma related and convergent epigenetic control are required during the Arabidopsis life cycle.

Directory of Open Access Journals (Sweden)

Amal J Johnston

2010-06-01

Full Text Available The plant life cycle alternates between two distinct multi-cellular generations, the reduced gametophytes and the dominant sporophyte. Little is known about how generation-specific cell fate, differentiation, and development are controlled by the core regulators of the cell cycle. In Arabidopsis, RETINOBLASTOMA RELATED (RBR, an evolutionarily ancient cell cycle regulator, controls cell proliferation, differentiation, and regulation of a subset of Polycomb Repressive Complex 2 (PRC2 genes and METHYLTRANSFERASE 1 (MET1 in the male and female gametophytes, as well as cell fate establishment in the male gametophyte. Here we demonstrate that RBR is also essential for cell fate determination in the female gametophyte, as revealed by loss of cell-specific marker expression in all the gametophytic cells that lack RBR. Maintenance of genome integrity also requires RBR, because diploid plants heterozygous for rbr (rbr/RBR produce an abnormal portion of triploid offspring, likely due to gametic genome duplication. While the sporophyte of the diploid mutant plants phenocopied wild type due to the haplosufficiency of RBR, genetic analysis of tetraploid plants triplex for rbr (rbr/rbr/rbr/RBR revealed that RBR has a dosage-dependent pleiotropic effect on sporophytic development, trichome differentiation, and regulation of PRC2 subunit genes CURLY LEAF (CLF and VERNALIZATION 2 (VRN2, and MET1 in leaves. There were, however, no obvious cell cycle and cell proliferation defects in these plant tissues, suggesting that a single functional RBR copy in tetraploids is capable of maintaining normal cell division but is not sufficient for distinct differentiation and developmental processes. Conversely, in leaves of mutants in sporophytic PRC2 subunits, trichome differentiation was also affected and expression of RBR and MET1 was reduced, providing evidence for a RBR-PRC2-MET1 regulatory feedback loop involved in sporophyte development. Together, dosage-sensitive RBR

Distribution of defects in wind turbine blades and reliability assessment of blades containing defects

DEFF Research Database (Denmark)

Stensgaard Toft, Henrik; Branner, Kim; Berring, Peter

2009-01-01

on the assumption that one error in the production process tends to trigger several defects. For both models additional information about number, type and size of the defects is included as stochastic variables. The probability of failure for a wind turbine blade will not only depend on variations in the material......In the present paper two stochastic models for the distribution of defects in wind turbine blades are proposed. The first model assumes that the individual defects are completely randomly distributed in the blade. The second model assumes that the defects occur in clusters of different size based...... properties and the load but also on potential defects in the blades. As a numerical example the probability of failure is calculated for the main spar both with and without defects in terms of delaminations. The delaminations increase the probability of failure compared to a perfect blade, but by applying...

Congenital heart defects in Williams syndrome.

Science.gov (United States)

Yuan, Shi-Min

2017-01-01

Yuan SM. Congenital heart defects in Williams syndrome. Turk J Pediatr 2017; 59: 225-232. Williams syndrome (WS), also known as Williams-Beuren syndrome, is a rare genetic disorder involving multiple systems including the circulatory system. However, the etiologies of the associated congenital heart defects in WS patients have not been sufficiently elucidated and represent therapeutic challenges. The typical congenital heart defects in WS were supravalvar aortic stenosis, pulmonary stenosis (both valvular and peripheral), aortic coarctation and mitral valvar prolapse. The atypical cardiovascular anomalies include tetralogy of Fallot, atrial septal defects, aortic and mitral valvular insufficiencies, bicuspid aortic valves, ventricular septal defects, total anomalous pulmonary venous return, double chambered right ventricle, Ebstein anomaly and arterial anomalies. Deletion of the elastin gene on chromosome 7q11.23 leads to deficiency or abnormal deposition of elastin during cardiovascular development, thereby leading to widespread cardiovascular abnormalities in WS. In this article, the distribution, treatment and surgical outcomes of typical and atypical cardiac defects in WS are discussed.

Serine biosynthesis and transport defects.

Science.gov (United States)

El-Hattab, Ayman W

2016-07-01

l-serine is a non-essential amino acid that is biosynthesized via the enzymes phosphoglycerate dehydrogenase (PGDH), phosphoserine aminotransferase (PSAT), and phosphoserine phosphatase (PSP). Besides its role in protein synthesis, l-serine is a potent neurotrophic factor and a precursor of a number of essential compounds including phosphatidylserine, sphingomyelin, glycine, and d-serine. Serine biosynthesis defects result from impairments of PGDH, PSAT, or PSP leading to systemic serine deficiency. Serine biosynthesis defects present in a broad phenotypic spectrum that includes, at the severe end, Neu-Laxova syndrome, a lethal multiple congenital anomaly disease, intermediately, infantile serine biosynthesis defects with severe neurological manifestations and growth deficiency, and at the mild end, the childhood disease with intellectual disability. A serine transport defect resulting from deficiency of the ASCT1, the main transporter for serine in the central nervous system, has been recently described in children with neurological manifestations that overlap with those observed in serine biosynthesis defects. l-serine therapy may be beneficial in preventing or ameliorating symptoms in serine biosynthesis and transport defects, if started before neurological damage occurs. Herein, we review serine metabolism and transport, the clinical, biochemical, and molecular aspects of serine biosynthesis and transport defects, the mechanisms of these diseases, and the potential role of serine therapy. Copyright © 2016 Elsevier Inc. All rights reserved.

Lectures on cosmic topological defects

Energy Technology Data Exchange (ETDEWEB)

Vachaspati, T [Department of Astronomy and Astrophysics, Colaba, Mumbai (India) and Physics Department, Case Western Reserve University, Cleveland (United States)

2001-11-15

These lectures review certain topological defects and aspects of their cosmology. Unconventional material includes brief descriptions of electroweak defects, the structure of domain walls in non-Abelian theories, and the spectrum of magnetic monopoles in SU(5) Grand Unified theory. (author)

Defects and defect processes in nonmetallic solids

CERN Document Server

Hayes, W

2004-01-01

This extensive survey covers defects in nonmetals, emphasizing point defects and point-defect processes. It encompasses electronic, vibrational, and optical properties of defective solids, plus dislocations and grain boundaries. 1985 edition.

Vertebral defect, anal atresia, cardiac defect, tracheoesophageal fistula/esophageal atresia, renal defect, and limb defect association with Mayer-Rokitansky-Küster-Hauser syndrome in co-occurrence: two case reports and a review of the literature.

Science.gov (United States)

Bjørsum-Meyer, Thomas; Herlin, Morten; Qvist, Niels; Petersen, Michael B

2016-12-21

defect, and limb defect association and Mayer-Rokitansky-Küster-Hauser syndrome is extremely rare. This group of patients has unusual phenotypic characteristics. The long-term outcome after treatment of defects is not well reported. A single unifying cause is not known and the etiology probably includes both genetic and non-genetic causes. We stress the importance of future studies to optimized treatment, follow-up, and etiology.

Tissue-engineered cartilaginous constructs for the treatment of caprine cartilage defects, including distribution of laminin and type IV collagen.

Science.gov (United States)

Jeng, Lily; Hsu, Hu-Ping; Spector, Myron

2013-10-01

The purpose of this study was the immunohistochemical evaluation of (1) cartilage tissue-engineered constructs; and (2) the tissue filling cartilage defects in a goat model into which the constructs were implanted, particularly for the presence of the basement membrane molecules, laminin and type IV collagen. Basement membrane molecules are localized to the pericellular matrix in normal adult articular cartilage, but have not been examined in tissue-engineered constructs cultured in vitro or in tissue filling cartilage defects into which the constructs were implanted. Cartilaginous constructs were engineered in vitro using caprine chondrocyte-seeded type II collagen scaffolds. Autologous constructs were implanted into 4-mm-diameter defects created to the tidemark in the trochlear groove in the knee joints of skeletally mature goats. Eight weeks after implantation, the animals were sacrificed. Constructs underwent immunohistochemical and histomorphometric evaluation. Widespread staining for the two basement membrane molecules was observed throughout the extracellular matrix of in vitro and in vivo samples in a distribution unlike that previously reported for cartilage. At sacrifice, 70% of the defect site was filled with reparative tissue, which consisted largely of fibrous tissue and some fibrocartilage, with over 70% of the reparative tissue bonded to the adjacent host tissue. A novel finding of this study was the observation of laminin and type IV collagen in in vitro engineered cartilaginous constructs and in vivo cartilage repair samples from defects into which the constructs were implanted, as well as in normal caprine articular cartilage. Future work is needed to elucidate the role of basement membrane molecules during cartilage repair and regeneration.

Topological defects in open string field theory

Science.gov (United States)

Kojita, Toshiko; Maccaferri, Carlo; Masuda, Toru; Schnabl, Martin

2018-04-01

We show how conformal field theory topological defects can relate solutions of open string field theory for different boundary conditions. To this end we generalize the results of Graham and Watts to include the action of defects on boundary condition changing fields. Special care is devoted to the general case when nontrivial multiplicities arise upon defect action. Surprisingly the fusion algebra of defects is realized on open string fields only up to a (star algebra) isomorphism.

Dehydration protection provided by a maternal cuticle improves offspring fitness in the moss Funaria hygrometrica.

Science.gov (United States)

Budke, Jessica M; Goffinet, Bernard; Jones, Cynthia S

2013-05-01

In bryophytes the sporophyte offspring are in contact with, nourished from, and partially surrounded by the maternal gametophyte throughout their lifespan. During early development, the moss sporophyte is covered by the calyptra, a cap of maternal gametophyte tissue that has a multilayered cuticle. In this study the effects on sporophyte offspring fitness of removing the maternal calyptra cuticle, in combination with dehydration stress, is experimentally determined. Using the moss Funaria hygrometrica, calyptra cuticle waxes were removed by chemical extraction and individuals were exposed to a short-term dehydration event. Sporophytes were returned to high humidity to complete development and then aspects of sporophyte survival, development, functional morphology, and reproductive output were measured. It was found that removal of calyptra cuticle under low humidity results in significant negative impacts to moss sporophyte fitness, resulting in decreased survival, increased tissue damage, incomplete sporophyte development, more peristome malformations, and decreased reproductive output. This study represents the strongest evidence to date that the structure of the calyptra cuticle functions in dehydration protection of the immature moss sporophyte. The investment in a maternal calyptra with a multilayered cuticle increases offspring fitness and provides a functional explanation for calyptra retention across mosses. The moss calyptra may represent the earliest occurance of maternal protection via structural provisioning of a cuticle in green plants.

Bilaterally symmetric axes with rhizoids composed the rooting structure of the common ancestor of vascular plants.

Science.gov (United States)

Hetherington, Alexander J; Dolan, Liam

2018-02-05

There are two general types of rooting systems in extant land plants: gametophyte rhizoids and sporophyte root axes. These structures carry out the rooting function in the free-living stage of almost all land plant gametophytes and sporophytes, respectively. Extant vascular plants develop a dominant, free-living sporophyte on which roots form, with the exception of a small number of taxa that have secondarily lost roots. However, fossil evidence indicates that early vascular plants did not develop sporophyte roots. We propose that the common ancestor of vascular plants developed a unique rooting system-rhizoidal sporophyte axes. Here we present a synthesis and reinterpretation of the rootless sporophytes of Horneophyton lignieri , Aglaophyton majus , Rhynia gwynne-vaughanii and Nothia aphylla preserved in the Rhynie chert. We show that the sporophyte rooting structures of all four plants comprised regions of plagiotropic (horizontal) axes that developed unicellular rhizoids on their underside. These regions of axes with rhizoids developed bilateral symmetry making them distinct from the other regions which were radially symmetrical. We hypothesize that rhizoidal sporophyte axes constituted the rooting structures in the common ancestor of vascular plants because the phylogenetic positions of these plants span the origin of the vascular lineage.This article is part of a discussion meeting issue 'The Rhynie cherts: our earliest terrestrial ecosystem revisited'. © 2017 The Authors.

Simulation based mask defect repair verification and disposition

Science.gov (United States)

Guo, Eric; Zhao, Shirley; Zhang, Skin; Qian, Sandy; Cheng, Guojie; Vikram, Abhishek; Li, Ling; Chen, Ye; Hsiang, Chingyun; Zhang, Gary; Su, Bo

2009-10-01

As the industry moves towards sub-65nm technology nodes, the mask inspection, with increased sensitivity and shrinking critical defect size, catches more and more nuisance and false defects. Increased defect counts pose great challenges in the post inspection defect classification and disposition: which defect is real defect, and among the real defects, which defect should be repaired and how to verify the post-repair defects. In this paper, we address the challenges in mask defect verification and disposition, in particular, in post repair defect verification by an efficient methodology, using SEM mask defect images, and optical inspection mask defects images (only for verification of phase and transmission related defects). We will demonstrate the flow using programmed mask defects in sub-65nm technology node design. In total 20 types of defects were designed including defects found in typical real circuit environments with 30 different sizes designed for each type. The SEM image was taken for each programmed defect after the test mask was made. Selected defects were repaired and SEM images from the test mask were taken again. Wafers were printed with the test mask before and after repair as defect printability references. A software tool SMDD-Simulation based Mask Defect Disposition-has been used in this study. The software is used to extract edges from the mask SEM images and convert them into polygons to save in GDSII format. Then, the converted polygons from the SEM images were filled with the correct tone to form mask patterns and were merged back into the original GDSII design file. This merge is for the purpose of contour simulation-since normally the SEM images cover only small area (~1 μm) and accurate simulation requires including larger area of optical proximity effect. With lithography process model, the resist contour of area of interest (AOI-the area surrounding a mask defect) can be simulated. If such complicated model is not available, a simple

ILT based defect simulation of inspection images accurately predicts mask defect printability on wafer

Science.gov (United States)

Deep, Prakash; Paninjath, Sankaranarayanan; Pereira, Mark; Buck, Peter

2016-05-01

At advanced technology nodes mask complexity has been increased because of large-scale use of resolution enhancement technologies (RET) which includes Optical Proximity Correction (OPC), Inverse Lithography Technology (ILT) and Source Mask Optimization (SMO). The number of defects detected during inspection of such mask increased drastically and differentiation of critical and non-critical defects are more challenging, complex and time consuming. Because of significant defectivity of EUVL masks and non-availability of actinic inspection, it is important and also challenging to predict the criticality of defects for printability on wafer. This is one of the significant barriers for the adoption of EUVL for semiconductor manufacturing. Techniques to decide criticality of defects from images captured using non actinic inspection images is desired till actinic inspection is not available. High resolution inspection of photomask images detects many defects which are used for process and mask qualification. Repairing all defects is not practical and probably not required, however it's imperative to know which defects are severe enough to impact wafer before repair. Additionally, wafer printability check is always desired after repairing a defect. AIMSTM review is the industry standard for this, however doing AIMSTM review for all defects is expensive and very time consuming. Fast, accurate and an economical mechanism is desired which can predict defect printability on wafer accurately and quickly from images captured using high resolution inspection machine. Predicting defect printability from such images is challenging due to the fact that the high resolution images do not correlate with actual mask contours. The challenge is increased due to use of different optical condition during inspection other than actual scanner condition, and defects found in such images do not have correlation with actual impact on wafer. Our automated defect simulation tool predicts

Computer programs for eddy-current defect studies

Energy Technology Data Exchange (ETDEWEB)

Pate, J. R.; Dodd, C. V. [Oak Ridge National Lab., TN (USA)

1990-06-01

Several computer programs to aid in the design of eddy-current tests and probes have been written. The programs, written in Fortran, deal in various ways with the response to defects exhibited by four types of probes: the pancake probe, the reflection probe, the circumferential boreside probe, and the circumferential encircling probe. Programs are included which calculate the impedance or voltage change in a coil due to a defect, which calculate and plot the defect sensitivity factor of a coil, and which invert calculated or experimental readings to obtain the size of a defect. The theory upon which the programs are based is the Burrows point defect theory, and thus the calculations of the programs will be more accurate for small defects. 6 refs., 21 figs.

Computer programs for eddy-current defect studies

International Nuclear Information System (INIS)

Pate, J.R.; Dodd, C.V.

1990-06-01

Several computer programs to aid in the design of eddy-current tests and probes have been written. The programs, written in Fortran, deal in various ways with the response to defects exhibited by four types of probes: the pancake probe, the reflection probe, the circumferential boreside probe, and the circumferential encircling probe. Programs are included which calculate the impedance or voltage change in a coil due to a defect, which calculate and plot the defect sensitivity factor of a coil, and which invert calculated or experimental readings to obtain the size of a defect. The theory upon which the programs are based is the Burrows point defect theory, and thus the calculations of the programs will be more accurate for small defects. 6 refs., 21 figs

Characterization of the structure and chemistry of defects in materials

International Nuclear Information System (INIS)

Larson, B.C.; Ruehle, M.; Seidman, D.N.

1988-01-01

Research programs, presented at the materials research symposium, on defects in materials are presented. Major areas include: point defects, defect aggregates, and ordering; defects in non-metals and semiconductors; atomic resolution imaging of defects; and gain boundaries, interfaces, and layered materials. Individual projects are processed separately for the data bases

Vertebral defect, anal atresia, cardiac defect, tracheoesophageal fistula/esophageal atresia, renal defect, and limb defect association with Mayer-Rokitansky-Küster-Hauser syndrome in co-occurrence

DEFF Research Database (Denmark)

Bjørsum-Meyer, Thomas; Herlin, Morten; Qvist, Niels

2016-01-01

Background: The vertebral defect, anal atresia, cardiac defect, tracheoesophageal fistula/esophageal atresia, renal defect, and limb defect association and Mayer-Rokitansky-Küster-Hauser syndrome are rare conditions. We aimed to present two cases with the vertebral defect, anal atresia, cardiac...... defect, tracheoesophageal fistula/esophageal atresia, renal defect, and limb defect association and Mayer-Rokitansky-Küster-Hauser co-occurrence from our local surgical center and through a systematic literature search detect published cases. Furthermore, we aimed to collect existing knowledge...... in the embryopathogenesis and genetics in order to discuss a possible link between the vertebral defect, anal atresia, cardiac defect, tracheoesophageal fistula/esophageal atresia, renal defect, and limb defect association and Mayer-Rokitansky-Küster-Hauser syndrome. Case presentation: Our first case was a white girl...

Secondary defects in non-metallic solids

International Nuclear Information System (INIS)

Ashbee, K.H.G.; Hobbs, L.W.

1977-01-01

This paper points out features of secondary defect formation which are peculiar to non-metallic solids (excluding elemental semiconductors). Most of the materials of interest are compounds of two or more (usually more or less ionic) atomic species, and immediate consequence of which is a need to maintain both stoichiometry (or accommodate non-stoichiometry) and order. Primary defects in these solids, whether produced thermally, chemically or by irradiation, seldom are present or aggregate in exactly stoichiometric proportions, and the resulting extending defect structures can be quite distinct from those found in metallic solids. Where stoichiometry is maintained, it is often convenient to describe extended defects in terms of alterations in the arrangement of 'molecular' units. The adoption of this procedure enables several novel features of extended defect structures in non-metals to be explained. There are several ways in which a range of non-stoichiometry can be accommodated, which include structural elimination of point defects, nucleation of new coherent phases of altered stoichiometry, and decomposition. (author)

Variability in per capita oogonia and sporophyte production from giant kelp gametophytes (Macrocystis pyrifera, Phaeophyceae Variabilidad de la producción per cápita de oogonios y esporofitos de huiro (Macrocystis pyrifera, Phaeophyceae

Directory of Open Access Journals (Sweden)

VERÓNICA MUÑOZ

2004-12-01

Full Text Available Vegetative growth and fertility of kelp gametophytes are thought to be antagonistic, such that most successful kelp recruitment is assumed to result from fertilization of single oogonia released from unicellular female gametophytes. We used laboratory culture experiments to study the effect of temperature and nutrient addition on the per capita production of oogonia and sporophytes from Macrocystis pyrifera female gametophytes. Our results indicate that individual multicellular female gametophytes can give rise to more than one oogonium and that per capita oogonia production significantly increases with the enhancement of culture conditions (i.e., decreased temperature and increased nutrient concentration. Furthermore, the production of multiple oogonia per female often led to the production of multiple sporophytes per female. We discuss the importance of these results relative to variability in M. pyrifera life histories (e.g., annual vs. perennial and their likely ecological and evolutionary consequencesEl crecimiento vegetativo y la fertilidad de gametofitos de huiros son antagónicos, de modo tal, que un reclutamiento exitoso se obtiene tras la fertilización de un único oogonio liberado por un gametofito femenino unicelular. Se utilizaron técnicas de cultivo de laboratorio para estudiar el efecto que ejerce la temperatura y la adición de nutrientes sobre la producción per cápita de oogonios y esporofitos de Macrocystis pyrifera. Nuestros resultados indican que gametofitos femeninos multicelulares pueden producir más de un oogonio y la producción per cápita incrementa significativamente al modificarse las condiciones de cultivo (por ejemplo disminución de la temperatura e incremento de las concentraciones de nutrientes. La producción de oogonios múltiples por gametofito femenino llevó la mayoría de los casos a una producción múltiple de esporofitos por hembra. Discutimos la importancia de estos resultados en relación a la

Birth Defects

Science.gov (United States)

A birth defect is a problem that happens while a baby is developing in the mother's body. Most birth defects happen during the first 3 months of ... in the United States is born with a birth defect. A birth defect may affect how the ...

Automatic classification of blank substrate defects

Science.gov (United States)

Boettiger, Tom; Buck, Peter; Paninjath, Sankaranarayanan; Pereira, Mark; Ronald, Rob; Rost, Dan; Samir, Bhamidipati

2014-10-01

Mask preparation stages are crucial in mask manufacturing, since this mask is to later act as a template for considerable number of dies on wafer. Defects on the initial blank substrate, and subsequent cleaned and coated substrates, can have a profound impact on the usability of the finished mask. This emphasizes the need for early and accurate identification of blank substrate defects and the risk they pose to the patterned reticle. While Automatic Defect Classification (ADC) is a well-developed technology for inspection and analysis of defects on patterned wafers and masks in the semiconductors industry, ADC for mask blanks is still in the early stages of adoption and development. Calibre ADC is a powerful analysis tool for fast, accurate, consistent and automatic classification of defects on mask blanks. Accurate, automated classification of mask blanks leads to better usability of blanks by enabling defect avoidance technologies during mask writing. Detailed information on blank defects can help to select appropriate job-decks to be written on the mask by defect avoidance tools [1][4][5]. Smart algorithms separate critical defects from the potentially large number of non-critical defects or false defects detected at various stages during mask blank preparation. Mechanisms used by Calibre ADC to identify and characterize defects include defect location and size, signal polarity (dark, bright) in both transmitted and reflected review images, distinguishing defect signals from background noise in defect images. The Calibre ADC engine then uses a decision tree to translate this information into a defect classification code. Using this automated process improves classification accuracy, repeatability and speed, while avoiding the subjectivity of human judgment compared to the alternative of manual defect classification by trained personnel [2]. This paper focuses on the results from the evaluation of Automatic Defect Classification (ADC) product at MP Mask

First-Principles Investigations of Defects in Minerals

Science.gov (United States)

Verma, Ashok K.

2011-07-01

The ideal crystal has an infinite 3-dimensional repetition of identical units which may be atoms or molecules. But real crystals are limited in size and they have disorder in stacking which as called defects. Basically three types of defects exist in solids: 1) point defects, 2) line defects, and 3) surface defects. Common point defects are vacant lattice sites, interstitial atoms and impurities and these are known to influence strongly many solid-state transport properties such as diffusion, electrical conduction, creep, etc. In thermal equilibrium point defects concentrations are determined by their formation enthalpies and their movement by their migration barriers. Line and surface defects are though absent from the ideal crystal in thermal equilibrium due to higher energy costs but they are invariably present in all real crystals. Line defects include edge-, screw- and mixed-dislocations and their presence is essential in explaining the mechanical strength and deformation of real crystals. Surface defects may arise at the boundary between two grains, or small crystals, within a larger crystal. A wide variety of grain boundaries can form in a polycrystal depending on factors such growth conditions and thermal treatment. In this talk we will present our first-principles density functional theory based defect studies of SiO2 polymorphs (stishovite, CaCl2-, α-PbO2-, and pyrite-type), Mg2SiO4 polymorphs (forsterite, wadsleyite and ringwoodite) and MgO [1-3]. Briefly, several native point defects including vacancies, interstitials, and their complexes were studied in silica polymorphs upto 200 GPa. Their values increase by a factor of 2 over the entire pressure range studied with large differences in some cases between different phases. The Schottky defects are energetically most favorable at zero pressure whereas O-Frenkel pairs become systematically more favorable at pressures higher than 20 GPa. The geometric and electronic structures of defects and migrating

Ultrasonic NDE Simulation for Composite Manufacturing Defects

Science.gov (United States)

Leckey, Cara A. C.; Juarez, Peter D.

2016-01-01

The increased use of composites in aerospace components is expected to continue into the future. The large scale use of composites in aerospace necessitates the development of composite-appropriate nondestructive evaluation (NDE) methods to quantitatively characterize defects in as-manufactured parts and damage incurred during or post manufacturing. Ultrasonic techniques are one of the most common approaches for defect/damage detection in composite materials. One key technical challenge area included in NASA's Advanced Composite's Project is to develop optimized rapid inspection methods for composite materials. Common manufacturing defects in carbon fiber reinforced polymer (CFRP) composites include fiber waviness (in-plane and out-of-plane), porosity, and disbonds; among others. This paper is an overview of ongoing work to develop ultrasonic wavefield based methods for characterizing manufacturing waviness defects. The paper describes the development and implementation of a custom ultrasound simulation tool that is used to model ultrasonic wave interaction with in-plane fiber waviness (also known as marcelling). Wavefield data processing methods are applied to the simulation data to explore possible routes for quantitative defect characterization.

Positron lifetime calculation for defects and defect clusters in graphite

International Nuclear Information System (INIS)

Onitsuka, T.; Ohkubo, H.; Takenaka, M.; Tsukuda, N.; Kuramoto, E.

2000-01-01

Calculations of positron lifetime have been made for vacancy type defects in graphite and compared with experimental results. Defect structures were obtained in a model graphite lattice after including relaxation of whole lattice as determined by the molecular dynamics method, where the interatomic potential given by Pablo Andribet, Dominguez-Vazguez, Mari Carmen Perez-Martin, Alonso, Jimenez-Rodriguez [Nucl. Instrum. and Meth. 115 (1996) 501] was used. For the defect structures obtained via lattice relaxation positron lifetime was calculated under the so-called atomic superposition method. Positron lifetimes 204 and 222 ps were obtained for the graphite matrix and a single vacancy, respectively, which can be compared with the experimental results 208 and 233 ps. For planar vacancy clusters, e.g., vacancy loops, lifetime calculation was also made and indicated that lifetime increases with the number of vacancies in a cluster. This is consistent with the experimental result in the region of higher annealing temperature (above 1200 deg. C), where the increase of positron lifetime is seen, probably corresponding to the clustering of mobile vacancies

Defects in Cu(In,Ga)Se{sub 2} chalcopyrite semiconductors: a comparative study of material properties, defect states, and photovoltaic performance

Energy Technology Data Exchange (ETDEWEB)

Cao, Qing; Gunawan, Oki; Copel, Matthew; Reuter, Kathleen B; Chey, S Jay; Mitzi, David B [IBM T.J. Watson Research Center, Yorktown Heights, NY (United States); Deline, Vaughn R [IBM Almaden Resesarch Center, San Jose, CA (United States)

2011-10-15

Understanding defects in Cu(In,Ga)(Se,S){sub 2} (CIGS), especially correlating changes in the film formation process with differences in material properties, photovoltaic (PV) device performance, and defect levels extracted from admittance spectroscopy, is a critical but challenging undertaking due to the complex nature of this polycrystalline compound semiconductor. Here we present a systematic comparative study wherein varying defect density levels in CIGS films were intentionally induced by growing CIGS grains using different selenium activity levels. Material characterization results by techniques including X-ray diffraction, scanning electron microscopy, transmission electron microscopy, secondary ion mass spectrometry, X-ray photoelectron spectroscopy, and medium energy ion scattering indicate that this process variation, although not significantly affecting CIGS grain structure, crystal orientation, or bulk composition, leads to enhanced formation of a defective chalcopyrite layer with high density of indium or gallium at copper antisite defects ((In, Ga){sub Cu}) near the CIGS surface, for CIGS films grown with insufficient selenium supply. This defective layer or the film growth conditions associated with it is further linked with observed current-voltage characteristics, including rollover and crossover behavior, and a defect state at around 110 meV (generally denoted as the N1 defect) commonly observed in admittance spectroscopy. The impact of the (In, Ga){sub Cu} defects on device PV performance is also established. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Theory of Defects in Semiconductors

CERN Document Server

Drabold, David A

2007-01-01

Semiconductor science and technology is the art of defect engineering. The theoretical modeling of defects has improved dramatically over the past decade. These tools are now applied to a wide range of materials issues: quantum dots, buckyballs, spintronics, interfaces, amorphous systems, and many others. This volume presents a coherent and detailed description of the field, and brings together leaders in theoretical research. Today's state-of-the-art, as well as tomorrow’s tools, are discussed: the supercell-pseudopotential method, the GW formalism,Quantum Monte Carlo, learn-on-the-fly molecular dynamics, finite-temperature treatments, etc. A wealth of applications are included, from point defects to wafer bonding or the propagation of dislocation.

Perception of risk from automobile safety defects.

Science.gov (United States)

Slovic, P; MacGregor, D; Kraus, N N

1987-10-01

Descriptions of safety engineering defects of the kind that compel automobile manufacturers to initiate a recall campaign were evaluated by individuals on a set of risk characteristic scales that included overall vehicle riskiness, manufacturer's ability to anticipate the defect, importance for vehicle operation, severity of consequences and likelihood of compliance with a recall notice. A factor analysis of the risk characteristics indicated that judgments could be summarized in terms of two composite scales, one representing the uncontrollability of the damage the safety defect might cause and the other representing the foreseeability of the defect by the manufacturer. Motor vehicle defects were found to be highly diverse in terms of the perceived qualities of their risks. Location of individual defects within the factor space was closely associated with perceived riskiness, perceived likelihood of purchasing another car from the same manufacturer, perceived likelihood of compliance with a recall notice, and actual compliance rates.

Impurity Role In Mechanically Induced Defects

International Nuclear Information System (INIS)

Howell, R.H.; Asoka-Kumar, P.; Hartley, J.; Sterne, P.

2000-01-01

An improved understanding of dislocation dynamics and interactions is an outstanding problem in the multi scale modeling of materials properties, and is the current focus of major theoretical efforts world wide. We have developed experimental and theoretical tools that will enable us to measure and calculate quantities defined by the defect structure. Unique to the measurements is a new spectroscopy that determines the detailed elemental composition at the defect site. The measurements are based on positron annihilation spectroscopy performed with a 3 MeV positron beam [1]. Positron annihilation spectroscopy is highly sensitive to dislocations and associated defects and can provide unique elements of the defect size and structure. Performing this spectroscopy with a highly penetrating positron beam enables flexibility in sample handling. Experiments on fatigued and stressed samples have been done and in situ measurement capabilities have been developed. We have recently performed significant upgrades to the accelerator operation and novel new experiments have been performed [2-4] To relate the spectrographic results and the detailed structure of a defect requires detailed calculations. Measurements are coupled with calculated results based on a description of positions of atoms at the defect. This gives an atomistic view of dislocations and associated defects including impurity interactions. Our ability to probe impurity interactions is a unique contribution to defect understanding not easily addressed by other atomistic spectroscopies

Buildability as a tool for optimisation of building defects

DEFF Research Database (Denmark)

Nielsen, Jørgen; Hansen, Ernst Jan de Place; Aagaard, Niels-Jørgen

2009-01-01

Defects in buildings harm the reputation of the construction industry and the amount of defects is believed to represent a loss in economy. The purpose is to study whether the buildability concept could serve as an efficient tool for reduction of defects. The project includes a literature study a...

Structural defects in monocrystalline silicon: from radiation ones to growing and technological

International Nuclear Information System (INIS)

Gerasimenko, N.N.; Pavlyuchenko, M.N.; Dzhamanbalin, K.K.

2001-01-01

The systematical review of properties and conditions of radiation structures in monocrystalline silicon including own defects (elementary and complex, disordered fields) as well as defect-impurity formations is presented. The most typical examples of principle effects influence of known defects on radiation-induced processes (phase transformations, diffusion and heteration and others are considered. Experimental facts and models of silicon radiation amorphization have been analyzed in comparison of state of the radiation amorphization radiation problem of metals and alloys. The up-to-date status of the problem of the radiation defects physics are discussed, including end-of-range -, n+-, rod-like- defects. The phenomenon self-organization in crystals with defects has been considered. The examples of directed using radiation defects merged in independent trend - defects engineering - are given

Comparison of RNA expression profiles on generations of Porphyra yezoensis (Rhodophyta, based on suppression subtractive hybridization (SSH

Directory of Open Access Journals (Sweden)

Shen Songdong

2011-10-01

Full Text Available Abstract Background Porphyra yezoensis Ueda is one of the most important edible seaweed, with a dimorphic life cycle which consists of gametophyte as macroscopical blade and sporophyte as microscopic filamentous. Conspicuous differences exist in the two generations, such as morphology, cell structure, biochemistry, physiology, and so on. The developmental process of Porphyra yezoensis has been studied thoroughly, but the mechanism is still ambiguous and few studies on genetic expression have been carried out. In this study, the suppression subtractive hybridization (SSH method conducted to generate large-scale expressed sequence tags (EST is designed to identify gene candidates related to the morphological and physiological differences between the gametophytic and sporophytic generations of Porphyra yezoensis Ueda. Findings Each 300 clones of sporophyte and gametophyte cells were dipped onto the membrane for hybridization. The result of dot-blot suggested there were 222 positive clones in gametophyte library and 236 positive clones in sporophyte library. 383 positive clones of strongest signals had been sequenced, and 191 EST sequences of gametophyte and 192 of sporophyte were obtained. A total of 196 genes were obtained, within which 104 genes were identified from the gametophyte and 92 from the sporophyte. Thirty-nine genes of the gametophyte and 62 genes of the sporophyte showed sequence similarity to those genes with known or putative functions which were classified according to their putative biological roles and molecular functions. The GO annotation showed about 58% of the cellular component of sporophyte and gametophyte cells were mainly located in cytoplasm and nucleus. The special genes were located in Golgi apparatus, and high expression in plastid, ribosome and endoplasmic reticulum. The main biological functions of gametophyte cells contributed to DNA repair/replication, carbohydrate metabolism, transport and transcription

Teratology: from science to birth defects prevention.

Science.gov (United States)

Rasmussen, Sonja A; Erickson, J David; Reef, Susan E; Ross, Danielle S

2009-01-01

One of the goals of birth defects research is to better understand risk or preventive factors for birth defects so that strategies for prevention can be developed. In this article, we have selected four areas of birth defects research that have led to the development of prevention strategies. These areas include rubella virus as a cause of congenital rubella syndrome, folic acid as a preventive factor for neural tube defects, cytomegalovirus infection as a cause of birth defects and developmental disabilities, and alcohol as a cause of fetal alcohol spectrum disorders. For each of these areas, we review key clinical and research findings that led to the identification of the risk or preventive factor, milestones in the development of prevention strategies, and the progress made thus far toward prevention.

Defect identification for the AsGa family

International Nuclear Information System (INIS)

Overhof, H.; Spaeth, J.-M.

2003-01-01

The As Ga family consists of at least four distinctly different point defects including the technologically important EL2 defect. While the different members are easily distinguished from their MCDA spectra, the differences of the hf and shf interactions as derived from ODEPR and ODENDOR are rather small. We present ab initio calculations using the LMTO-ASA Green's function method for a variety of defect models that might be relevant for the identification of As Ga -related defects. We confirm the identification of the isolated As Ga and show that the {As Ga -X 2 } defect must be identified with the nearest-neighbor antistructure pair rather than with the {As Ga -V As } pair. For the {As Ga -X 1 } defect a distant antistructure pair is a likely candidate. For the EL2, the most important member of the As Ga family, we have not found a conclusive defect model. The recent ODENDOR data are similar to those of the distant orthorhombic {As Ga -V Ga } pair, which, however is a triple acceptor and not a donor

Thyroid Medication Use and Birth Defects in the National Birth Defects Prevention Study.

Science.gov (United States)

Howley, Meredith M; Fisher, Sarah C; Van Zutphen, Alissa R; Waller, Dorothy K; Carmichael, Suzan L; Browne, Marilyn L

2017-11-01

Thyroid disorders are common among reproductive-aged women, with hypothyroidism affecting 2 to 3% of pregnancies, and hyperthyroidism affecting an additional 0.1 to 1%. We examined associations between thyroid medications and individual birth defects using data from the National Birth Defects Prevention Study (NBDPS). The NBDPS is a multisite, population-based, case-control study that included pregnancies with estimated delivery dates from 1997 to 2011. We analyzed self-reported thyroid medication use from mothers of 31,409 birth defect cases and 11,536 unaffected controls. Adjusted odds ratios (ORs) and 95% confidence intervals (CIs) were estimated using logistic regression for birth defects with five or more exposed cases, controlling for maternal age, race/ethnicity, and study center. Crude ORs and exact 95% CIs were estimated for defects with 3 to 4 exposed cases. Thyroid hormone was used by 738 (2.3%) case and 237 (2.1%) control mothers, and was associated with anencephaly (OR = 1.68; 95% CI, 1.03-2.73), holoprosencephaly (OR = 2.48; 95% CI, 1.13-5.44), hydrocephaly (1.77; 95% CI, 1.07-2.95) and small intestinal atresia (OR = 1.81; 95% CI, 1.04-3.15). Anti-thyroid medication was used by 34 (0.1%) case and 10 (<0.1%) control mothers, and was associated with aortic valve stenosis (OR = 6.91; 95% CI, 1.21-27.0). While new associations were identified, our findings are relatively consistent with previous NBDPS analyses. Our findings suggest thyroid medication use is not associated with most birth defects studied in the NBDPS, but may be associated with some specific birth defects. These results should not be interpreted to suggest that medications used to treat thyroid disease are teratogens, as the observed associations may reflect effects of the underlying thyroid disease. Birth Defects Research 109:1471-1481, 2017.© 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

A Study of Defect Behavior in Almandine Garnet

Science.gov (United States)

Geiger, C. A.; Brearley, A. J.; Dachs, E.; Tipplet, G.; Rossman, G. R.

2016-12-01

Transport and diffusion in crystals are controlled by defects. However, a good understanding of the defect types in many silicates, including garnet, is not at hand. We undertook a study on synthetic almandine, ideal end-member Fe3Al2Si3O12, to better understand its precise chemical and physical properties and defect behavior. Crystals were synthesized at high pressures and temperatures under different fO2 conditions using various starting materials with H2O and without. The almandine obtained came in polycrystalline and single-crystal form. The synthetic reaction products and crystals were carefully characterized using X-ray powder diffraction, electron microprobe and TEM analysis and with 57Fe Mössbauer, UV/VIS single-crystal absorption and IR single-crystal spectroscopy. Various possible intrinsic defects, such as the Frenkel, Schottky and site-disorder types, along with Fe3+, in both synthetic and natural almandine crystals, were analyzed based on model defects expressed in Kröger-Vink notation. Certain types of minor microscopic- to macroscopic-sized precipitation or exsolution phases, including some that are nanosized, that are observed in synthetic almandine (e.g., magnetite), as well as in more compositionally complex natural crystals (e.g., magnetite, rutile, ilmenite), may result from defect reactions. An explanation for their origin through minor amounts of defects in garnet has certain advantages over other models that have been put forth in the literature that assume strict garnet stoichiometry for their formation and/or open-system atomic transport over relatively long length scales. Physical properties, including magnetic, electrical conductivity and diffusion behavior, as well as the color, of almandine are also analyzed in terms of various possible model defects. It is difficult, if not impossible, to synthesize stoichiometric end-member almandine, Fe3Al2Si3O12, in the laboratory, as small amounts of extrinsic OH- and/or Fe3+ defects, for example

Agricultural Compounds in Water and Birth Defects.

Science.gov (United States)

Brender, Jean D; Weyer, Peter J

2016-06-01

Agricultural compounds have been detected in drinking water, some of which are teratogens in animal models. The most commonly detected agricultural compounds in drinking water include nitrate, atrazine, and desethylatrazine. Arsenic can also be an agricultural contaminant, although arsenic often originates from geologic sources. Nitrate has been the most studied agricultural compound in relation to prenatal exposure and birth defects. In several case-control studies published since 2000, women giving birth to babies with neural tube defects, oral clefts, and limb deficiencies were more likely than control mothers to be exposed to higher concentrations of drinking water nitrate during pregnancy. Higher concentrations of atrazine in drinking water have been associated with abdominal defects, gastroschisis, and other defects. Elevated arsenic in drinking water has also been associated with birth defects. Since these compounds often occur as mixtures, it is suggested that future research focus on the impact of mixtures, such as nitrate and atrazine, on birth defects.

Immobile defects in ferroelastic walls: Wall nucleation at defect sites

Science.gov (United States)

He, X.; Salje, E. K. H.; Ding, X.; Sun, J.

2018-02-01

Randomly distributed, static defects are enriched in ferroelastic domain walls. The relative concentration of defects in walls, Nd, follows a power law distribution as a function of the total defect concentration C: N d ˜ C α with α = 0.4 . The enrichment Nd/C ranges from ˜50 times when C = 10 ppm to ˜3 times when C = 1000 ppm. The resulting enrichment is due to nucleation at defect sites as observed in large scale MD simulations. The dynamics of domain nucleation and switching is dependent on the defect concentration. Their energy distribution follows the power law with exponents during yield between ɛ ˜ 1.82 and 2.0 when the defect concentration increases. The power law exponent is ɛ ≈ 2.7 in the plastic regime, independent of the defect concentration.

Effect of interaction between irradiation-induced defects and intrinsic defects in the pinning improvement of neutron irradiated YBaCuO sample

International Nuclear Information System (INIS)

Topal, Ugur; Sozeri, Huseyin; Yavuz, Hasbi

2004-01-01

Interaction between the intrinsic (native) defects and the irradiation-induced defects created by neutron irradiation was examined for the YBCO sample. For this purpose, non-superconducting Y-211 phase was included to the Y-123 samples at different contents as a source of large pinning center. The critical current density enhancement with the irradiation for these samples were analysed and then the role of defects on pinning improvement was discussed

Effect of interaction between irradiation-induced defects and intrinsic defects in the pinning improvement of neutron irradiated YBaCuO sample

Energy Technology Data Exchange (ETDEWEB)

Topal, Ugur; Sozeri, Huseyin; Yavuz, Hasbi

2004-08-01

Interaction between the intrinsic (native) defects and the irradiation-induced defects created by neutron irradiation was examined for the YBCO sample. For this purpose, non-superconducting Y-211 phase was included to the Y-123 samples at different contents as a source of large pinning center. The critical current density enhancement with the irradiation for these samples were analysed and then the role of defects on pinning improvement was discussed.

Ultrasonic defect characterization using parametric-manifold mapping

Science.gov (United States)

Velichko, A.; Bai, L.; Drinkwater, B. W.

2017-06-01

The aim of ultrasonic non-destructive evaluation includes the detection and characterization of defects, and an understanding of the nature of defects is essential for the assessment of structural integrity in safety critical systems. In general, the defect characterization challenge involves an estimation of defect parameters from measured data. In this paper, we explore the extent to which defects can be characterized by their ultrasonic scattering behaviour. Given a number of ultrasonic measurements, we show that characterization information can be extracted by projecting the measurement onto a parametric manifold in principal component space. We show that this manifold represents the entirety of the characterization information available from far-field harmonic ultrasound. We seek to understand the nature of this information and hence provide definitive statements on the defect characterization performance that is, in principle, extractable from typical measurement scenarios. In experiments, the characterization problem of surface-breaking cracks and the more general problem of elliptical voids are studied, and a good agreement is achieved between the actual parameter values and the characterization results. The nature of the parametric manifold enables us to explain and quantify why some defects are relatively easy to characterize, whereas others are inherently challenging.

Studies of defects and defect agglomerates by positron annihilation spectroscopy

DEFF Research Database (Denmark)

Eldrup, Morten Mostgaard; Singh, B.N.

1997-01-01

A brief introduction to positron annihilation spectroscopy (PAS), and in particular lo its use for defect studies in metals is given. Positrons injected into a metal may become trapped in defects such as vacancies, vacancy clusters, voids, bubbles and dislocations and subsequently annihilate from...... the trapped state iri the defect. The annihilation characteristics (e.g., the lifetime of the positron) can be measured and provide information about the nature of the defect (e.g., size, density, morphology). The technique is sensitive to both defect size (in the range from monovacancies up to cavities...

Defect modelling

International Nuclear Information System (INIS)

Norgett, M.J.

1980-01-01

Calculations, drawing principally on developments at AERE Harwell, of the relaxation about lattice defects are reviewed with emphasis on the techniques required for such calculations. The principles of defect modelling are outlined and various programs developed for defect simulations are discussed. Particular calculations for metals, ionic crystals and oxides, are considered. (UK)

Polydispersity-driven topological defects as order-restoring excitations.

Science.gov (United States)

Yao, Zhenwei; Olvera de la Cruz, Monica

2014-04-08

The engineering of defects in crystalline matter has been extensively exploited to modify the mechanical and electrical properties of many materials. Recent experiments on manipulating extended defects in graphene, for example, show that defects direct the flow of electric charges. The fascinating possibilities offered by defects in two dimensions, known as topological defects, to control material properties provide great motivation to perform fundamental investigations to uncover their role in various systems. Previous studies mostly focus on topological defects in 2D crystals on curved surfaces. On flat geometries, topological defects can be introduced via density inhomogeneities. We investigate here topological defects due to size polydispersity on flat surfaces. Size polydispersity is usually an inevitable feature of a large variety of systems. In this work, simulations show well-organized induced topological defects around an impurity particle of a wrong size. These patterns are not found in systems of identical particles. Our work demonstrates that in polydispersed systems topological defects play the role of restoring order. The simulations show a perfect hexagonal lattice beyond a small defective region around the impurity particle. Elasticity theory has demonstrated an analogy between the elementary topological defects named disclinations to electric charges by associating a charge to a disclination, whose sign depends on the number of its nearest neighbors. Size polydispersity is shown numerically here to be an essential ingredient to understand short-range attractions between like-charge disclinations. Our study suggests that size polydispersity has a promising potential to engineer defects in various systems including nanoparticles and colloidal crystals.

The role of point defects and defect complexes in silicon device processing. Summary report and papers

Energy Technology Data Exchange (ETDEWEB)

Sopori, B.; Tan, T.Y.

1994-08-01

This report is a summary of a workshop hold on August 24--26, 1992. Session 1 of the conference discussed characteristics of various commercial photovoltaic silicon substrates, the nature of impurities and defects in them, and how they are related to the material growth. Session 2 on point defects reviewed the capabilities of theoretical approaches to determine equilibrium structure of defects in the silicon lattice arising from transitional metal impurities and hydrogen. Session 3 was devoted to a discussion of the surface photovoltaic method for characterizing bulk wafer lifetimes, and to detailed studies on the effectiveness of various gettering operations on reducing the deleterious effects of transition metals. Papers presented at the conference are also included in this summary report.

Local defect resonance for sensitive non-destructive testing

Science.gov (United States)

Adebahr, W.; Solodov, I.; Rahammer, M.; Gulnizkij, N.; Kreutzbruck, M.

2016-02-01

Ultrasonic wave-defect interaction is a background of ultrasound activated techniques for imaging and non-destructive testing (NDT) of materials and industrial components. The interaction, primarily, results in acoustic response of a defect which provides attenuation and scattering of ultrasound used as an indicator of defects in conventional ultrasonic NDT. The derivative ultrasonic-induced effects include e.g. nonlinear, thermal, acousto-optic, etc. responses also applied for NDT and defect imaging. These secondary effects are normally relatively inefficient so that the corresponding NDT techniques require an elevated acoustic power and stand out from conventional ultrasonic NDT counterparts for their specific instrumentation particularly adapted to high-power ultrasonic. In this paper, a consistent way to enhance ultrasonic, optical and thermal defect responses and thus to reduce an ultrasonic power required is suggested by using selective ultrasonic activation of defects based on the concept of local defect resonance (LDR). A strong increase in vibration amplitude at LDR enables to reliably detect and visualize the defect as soon as the driving ultrasonic frequency is matched to the LDR frequency. This also provides a high frequency selectivity of the LDR-based imaging, i.e. an opportunity of detecting a certain defect among a multitude of other defects in material. Some examples are shown how to use LDR in non-destructive testing techniques, like vibrometry, ultrasonic thermography and shearography in order to enhance the sensitivity of defect visualization.

Effects of in-cascade defect clustering on near-term defect evolution

Energy Technology Data Exchange (ETDEWEB)

Heinisch, H.L. [Pacific Northwest National Lab., Richland, WA (United States)

1997-08-01

The effects of in-cascade defect clustering on the nature of the subsequent defect population are being studied using stochastic annealing simulations applied to cascades generated in molecular dynamics (MD) simulations. The results of the simulations illustrates the strong influence of the defect configuration existing in the primary damage state on subsequent defect evolution. The large differences in mobility and stability of vacancy and interstitial defects and the rapid one-dimensional diffusion of small, glissile interstitial loops produced directly in cascades have been shown to be significant factors affecting the evolution of the defect distribution. In recent work, the effects of initial cluster sizes appear to be extremely important.

If Your Child Has a Heart Defect (For Parents)

Science.gov (United States)

... Videos for Educators Search English Español If Your Child Has a Heart Defect KidsHealth / For Parents / If ... has any of these symptoms. Caring for Your Child Parenting kids with heart defects includes learning about ...

The effects of defects on copper melting under hydrostatic and shock loading

Energy Technology Data Exchange (ETDEWEB)

Luo, Shengnian [Los Alamos National Laboratory; An, Qi [Los Alamos National Laboratory; Germann, Timothy C [Los Alamos National Laboratory; Han, Li - Bo [USTC

2009-07-24

With molecular dynamics (MD) simulations, we investigate the effects of defects on Cu melting under hydrostatic and shock wave loading. We explore preexistent defects including vacancies, stacking faults and grain boundaries, as well as shock-induced defects. Depending on defect characteristics (energy and concentration), defects may have negligible or considerable effects on melting at MD scales However, it is expected that defects have more pronounced effects at heating rates lower than the MD rates.

Congenital heart defects and extracardiac malformations.

Science.gov (United States)

Rosa, Rosana Cardoso M; Rosa, Rafael Fabiano M; Zen, Paulo Ricardo G; Paskulin, Giorgio Adriano

2013-06-01

To review the association between congenital heart defects and extracardiac malformations. Scientific articles were searched in the Medline, Lilacs, and SciELO databases, using the descriptors "congenital heart disease," "congenital heart defects," "congenital cardiac malformations," "extracardiac defects," and "extracardiac malformations." All case series that specifically explored the association between congenital heart defects and extracardiac malformations were included. Congenital heart diseases are responsible for about 40% of birth defects, being one of the most common and severe malformations. Extracardiac malformations are observed in 7 to 50% of the patients with congenital heart disease, bringing a greater risk of comorbidity and mortality and increasing the risks related to heart surgery. Different studies have attempted to assess the presence of extracardiac abnormalities in patients with congenital heart disease. Among the changes described, those of the urinary tract are more often reported. However, no study has evaluated all patients in the same way. Extracardiac abnormalities are frequent among patients with congenital heart disease, and patients with these alterations may present an increased risk of morbimortality. Therefore, some authors have been discussing the importance and cost-effectiveness of screening these children for other malformations by complementary exams.

Defect dynamics and coarsening dynamics in smectic-C films

Science.gov (United States)

Pargellis, A. N.; Finn, P.; Goodby, J. W.; Panizza, P.; Yurke, B.; Cladis, P. E.

1992-12-01

We study the dynamics of defects generated in free-standing films of liquid crystals following a thermal quench from the smectic-A phase to the smectic-C phase. The defects are type-1 disclinations, and the strain field between defect pairs is confined to 2π walls. We compare our observations with a phenomenological model that includes dipole coupling of the director field to an external ordering field. This model is able to account for both the observed coalescence dynamics and the observed ordering dynamics. In the absence of an ordering field, our model predicts the defect density ρ to scale with time t as ρ lnρ~t-1. When the dipole coupling of the director field to an external ordering field is included, both the model and experiments show the defect coarsening proceeds as ρ~e-αt with the strain field confined to 2π walls. The external ordering field most likely arises from the director's tendency to align with edge dislocations within the liquid-crystal film.

Defect assessment procedures at high temperature

International Nuclear Information System (INIS)

Ainsworth, R.A.

1991-01-01

A comprehensive assessment procedure for the high-temperature response of structures is being produced. The procedure is referred to as R5 and is written as a series of step-by-step instructions in a number of volumes. This paper considers in detail those parts of R5 which address the behaviour of defects. The defect assessment procedures may be applied to defects found in service, postulated defects, or defects formed during operation as a result of creep-fatigue loading. In the last case, a method is described for deducing from endurance data the number of cycles to initiate a crack of a specified size. Under steady loading, the creep crack tip parameter C * is used to assess crack growth. Under cyclic loading, the creep crack growth during dwell periods is stiell governed by C * but crack growth due to cyclic excursions must also be included. This cyclic crack growth is described by an effective stress intensity factor range. A feature of the R5 defect assessment procedures in that they are based on simplified methods and approximate reference stress methods are described which enable C * in a component to be evaluated. It is shown by comparison with theoretical calculations and experimental data that reliable estimates of C * and the associated crack growth are obtained provided realistic creep strain rate date are used in the reference stress approximation. (orig./HP)

Fuel defect detection, localization and removal in Bruce Power units 3 through 8

International Nuclear Information System (INIS)

Stone, R.; Armstrong, J.; Iglesias, F.; Oduntan, R.; Lewis, B.

2005-01-01

Fuel element defects are occurring in Bruce 'A' and Bruce 'B' Units. A root-cause investigation is ongoing, however, a solution is not yet in-hand. Fuel defect management efforts have been undertaken, therefore, in the interim. Fuel defect management tools are in-place for all Bruce Units. These tools can be categorized as analysis-based or operations-based. Analysis-based tools include computer codes used primarily for fuel defect characterization, while operations-based tools include Unit-specific delayed-neutron ('DN') monitoring systems and gaseous fission product ('GFP') monitoring systems. Operations-based tools are used for fuel defect detection, localization and removal activities. Fuel and Physics staff use defect detection, localization and removal methodologies and guidelines to disposition fuel defects. Methodologies are 'standardized' or 'routine' procedures for implementing analysis-based and operations-based tools to disposition fuel defects during Unit start-up operation and during operation at high steady-state power levels. Guidelines at present serve to supplement fuel defect management methodologies during Unit power raise. (author)

Prevention of congenital defects induced by prenatal alcohol exposure (Conference Presentation)

Science.gov (United States)

Sheehan, Megan M.; Karunamuni, Ganga; Pedersen, Cameron J.; Gu, Shi; Doughman, Yong Qiu; Jenkins, Michael W.; Watanabe, Michiko; Rollins, Andrew M.

2017-02-01

Nearly 2 million women in the United States alone are at risk for an alcohol-exposed pregnancy, including more than 600,000 who binge drink. Even low levels of prenatal alcohol exposure (PAE) can lead to a variety of birth defects, including craniofacial and neurodevelopmental defects, as well as increased risk of miscarriages and stillbirths. Studies have also shown an interaction between drinking while pregnant and an increase in congenital heart defects (CHD), including atrioventricular septal defects and other malformations. We have previously established a quail model of PAE, modeling a single binge drinking episode in the third week of a woman's pregnancy. Using optical coherence tomography (OCT), we quantified intraventricular septum thickness, great vessel diameters, and atrioventricular valve volumes. Early-stage ethanol-exposed embryos had smaller cardiac cushions (valve precursors) and increased retrograde flow, while late-stage embryos presented with gross head/body defects, and exhibited smaller atrio-ventricular (AV) valves, interventricular septum, and aortic vessels. We previously showed that supplementation with the methyl donor betaine reduced gross defects, improved survival rates, and prevented cardiac defects. Here we show that these preventative effects are also observed with folate (another methyl donor) supplementation. Folate also appears to normalize retrograde flow levels which are elevated by ethanol exposure. Finally, preliminary findings have shown that glutathione, a crucial antioxidant, is noticeably effective at improving survival rates and minimizing gross defects in ethanol-exposed embryos. Current investigations will examine the impact of glutathione supplementation on PAE-related CHDs.

An Inherited Platelet Function Defect in Basset Hounds

Science.gov (United States)

Johnstone, I. B.; Lotz, F.

1979-01-01

An inherited platelet function defect occurring in a family of basset hounds has been described. The trait is transmitted as an autosomal characteristic and appears to be expressed clinically only in the homozygous state. The characteristics of this platelet defect include: 1) marked bleeding tendencies and prolonged skin bleeding times in either male or female dogs. 2) normal blood coagulation mechanism. 3) adequate numbers of circulating platelets which appear morphologically normal by light microscopy. 4) normal whole blood clot retraction. 5) deficient in vivo platelet consumption and in vitro platelet retention in glass bead columns. 6) defective ADP-induced platelet aggregation in homozygotes, apparently normal ADP response in heterozygotes, and defective collagen-induced platelet aggregation in both. PMID:509382

PREFACE: The International Workshop on Positron Studies of Defects 2014

Science.gov (United States)

Sugita, Kazuki; Shirai, Yasuharu

2016-01-01

The International Workshop on Positron Studies of Defects 2014 (PSD-14) was held in Kyoto, Japan from 14-19 September, 2014. The PSD Workshop brought together positron scientists interested in studying defects to an international platform for presenting and discussing recent results and achievements, including new experimental and theoretical methods in the field. The workshop topics can be characterized as follows: • Positron studies of defects in semiconductors and oxides • Positron studies of defects in metals • New experimental methods and equipment • Theoretical calculations and simulations of momentum distributions, positron lifetimes and other characteristics for defects • Positron studies of defects in combination with complementary methods • Positron beam studies of defects at surfaces, interfaces, in sub-surface regions and thin films • Nanostructures and amorphous materials

Neural Tube Defects

Science.gov (United States)

Neural tube defects are birth defects of the brain, spine, or spinal cord. They happen in the ... that she is pregnant. The two most common neural tube defects are spina bifida and anencephaly. In ...

A computational framework for automation of point defect calculations

International Nuclear Information System (INIS)

Goyal, Anuj; Gorai, Prashun; Peng, Haowei

2017-01-01

We have developed a complete and rigorously validated open-source Python framework to automate point defect calculations using density functional theory. Furthermore, the framework provides an effective and efficient method for defect structure generation, and creation of simple yet customizable workflows to analyze defect calculations. This package provides the capability to compute widely-accepted correction schemes to overcome finite-size effects, including (1) potential alignment, (2) image-charge correction, and (3) band filling correction to shallow defects. Using Si, ZnO and In2O3 as test examples, we demonstrate the package capabilities and validate the methodology.

Rail inspection of RCF defects

Directory of Open Access Journals (Sweden)

Z. Popović

2013-10-01

Full Text Available Rail defects due to rolling contact fatigue (RCF threaten the traffic safety around the world. That hazard is more distinct on railways without adequate maintenance strategy. Realization of interoperability of European railway network demands from every infrastructure manager to have a maintenance plan for the infrastructure subsystem. Besides that, this plan includes rail inspection and strategy against RCF defects. This paper emphasizes the importance of rail inspection and early detection of RCF because the most of RCF crack should be removed in rail grinding campaigns (preventive, cyclical and corrective activities during the whole rail service life.

Ionization-induced rearrangement of defects in silicon

International Nuclear Information System (INIS)

Vinetskij, V.L.; Manojlo, M.A.; Matvijchuk, A.S.; Strikha, V.I.; Kholodar', G.A.

1988-01-01

Ionizing factor effect on defect rearrangement in silicon including centers with deep local electron levels in the p-n-transition region is considered. Deep center parameters were determined using non-steady-state capacity spectroscopy of deep levels (NCDLS) method. NCDLS spectrum measurement was performed using source p + -n - diodes and after their irradiation with 15 keV energy electrons or laser pulses. It is ascertained that in silicon samples containing point defect clusters defect rearrangement under ionizing factor effect takes place, i.e. deep level spectra are changed. This mechanism is efficient in case of silicon irradiation with subthreshold energy photons and electrons and can cause degradation of silicon semiconducting structures

Reduction in Defect Content in ODS Alloys

Energy Technology Data Exchange (ETDEWEB)

Ritherdon, J.; Jones, A.R.

2000-02-01

The work detailed within this report is a continuation of earlier work that was carried out under contract number IDX-SY382V. The earlier work comprised a literature review of the sources and types of defects found principally in Fe-based ODS alloys together with a series of experiments designed to identify defects in ODS Fe{sub 3}Al material and recommend methods of defect reduction. Defects found in the Mechanically Alloyed (MA) ODS Fe{sub 3}Al included regions of incomplete MA, porosity, intrusions and fine-grained stringers. Some defects tended to be found in association with one another e.g. intrusions and fine-grained stringers. Preliminary powder separation experiments were also performed. The scope and objectives of the present work were laid out in the technical proposal ``Reduction in Defect Content in ODS Alloys--II'' which formed the basis of amendment 3 of the current contract. The current studies were devised in the context of the preceding work with a view to extending and concluding certain experiments while exploring new avenues of investigation of defect control and reduction where appropriate. All work proposed was within the context of achieving an ODS Fe{sub 3}Al alloy of improved overall quality and potential creep performance (particularly) in the consolidated, release condition. The interim outturn of the experimental work performed is also reported.

Identification of biochemical features of defective Coffea arabica L. beans.

Science.gov (United States)

Casas, María I; Vaughan, Michael J; Bonello, Pierluigi; McSpadden Gardener, Brian; Grotewold, Erich; Alonso, Ana P

2017-05-01

Coffee organoleptic properties are based in part on the quality and chemical composition of coffee beans. The presence of defective beans during processing and roasting contribute to off flavors and reduce overall cup quality. A multipronged approach was undertaken to identify specific biochemical markers for defective beans. To this end, beans were split into defective and non-defective fractions and biochemically profiled in both green and roasted states. A set of 17 compounds in green beans, including organic acids, amino acids and reducing sugars; and 35 compounds in roasted beans, dominated by volatile compounds, organic acids, sugars and sugar alcohols, were sufficient to separate the defective and non-defective fractions. Unsorted coffee was examined for the presence of the biochemical markers to test their utility in detecting defective beans. Although the green coffee marker compounds were found in all fractions, three of the roasted coffee marker compounds (1-methylpyrrole, 5-methyl- 2-furfurylfuran, and 2-methylfuran) were uniquely present in defective fractions. Published by Elsevier Ltd.

On holographic defect entropy

International Nuclear Information System (INIS)

Estes, John; Jensen, Kristan; O’Bannon, Andy; Tsatis, Efstratios; Wrase, Timm

2014-01-01

We study a number of (3+1)- and (2+1)-dimensional defect and boundary conformal field theories holographically dual to supergravity theories. In all cases the defects or boundaries are planar, and the defects are codimension-one. Using holography, we compute the entanglement entropy of a (hemi-)spherical region centered on the defect (boundary). We define defect and boundary entropies from the entanglement entropy by an appropriate background subtraction. For some (3+1)-dimensional theories we find evidence that the defect/boundary entropy changes monotonically under certain renormalization group flows triggered by operators localized at the defect or boundary. This provides evidence that the g-theorem of (1+1)-dimensional field theories generalizes to higher dimensions

Micro-bridge defects: characterization and root cause analysis

Science.gov (United States)

Santoro, Gaetano; Van den Heuvel, Dieter; Braggin, Jennifer; Rosslee, Craig; Leray, Philippe J.; Cheng, Shaunee; Jehoul, Christiane; Schreutelkamp, Robert; Hillel, Noam

2010-03-01

Defect review of advanced lithography processes is becoming more and more challenging as feature sizes decrease. Previous studies using a defect review SEM on immersion lithography generated wafers have resulted in a defect classification scheme which, among others, includes a category for micro-bridges. Micro-bridges are small connections between two adjacent lines in photo-resist and are considered device killing defects. Micro-bridge rates also tend to increase as feature sizes decrease, making them even more important for the next technology nodes. Especially because micro-bridge defects can originate from different root causes, the need to further refine and split up the classification of this type of defect into sub groups may become a necessity. This paper focuses on finding the correlation of the different types of micro-bridge defects to a particular root cause based on a full characterization and root cause analysis of this class of defects, by using advanced SEM review capabilities like high quality imaging in very low FOV, Multi Perspective SEM Imaging (MPSI), tilted column and rotated stage (Tilt&Rotation) imaging and Focused Ion Beam (FIB) cross sectioning. Immersion lithography material has been mainly used to generate the set of data presented in this work even though, in the last part of the results, some EUV lithography data will be presented as part of the continuing effort to extend the micro-bridge defect characterization to the EUV technology on 40 nm technology node and beyond.

Congenital heart defects in molecularly proven Kabuki syndrome patients.

Science.gov (United States)

Digilio, Maria Cristina; Gnazzo, Maria; Lepri, Francesca; Dentici, Maria Lisa; Pisaneschi, Elisa; Baban, Anwar; Passarelli, Chiara; Capolino, Rossella; Angioni, Adriano; Novelli, Antonio; Marino, Bruno; Dallapiccola, Bruno

2017-11-01

The prevalence of congenital heart defects (CHD) in Kabuki syndrome ranges from 28% to 80%. Between January 2012 and December 2015, 28 patients had a molecularly proven diagnosis of Kabuki syndrome. Pathogenic variants in KMT2D (MLL2) were detected in 27 patients, and in KDM6A gene in one. CHD was diagnosed in 19/27 (70%) patients with KMT2D (MLL2) variant, while the single patient with KDM6A change had a normal heart. The anatomic types among patients with CHD included aortic coarctation (4/19 = 21%) alone or associated with an additional CHD, bicuspid aortic valve (4/19 = 21%) alone or associated with an additional CHD, perimembranous subaortic ventricular septal defect (3/19 = 16%), atrial septal defect ostium secundum type (3/19 = 16%), conotruncal heart defects (3/19 = 16%). Additional CHDs diagnosed in single patients included aortic dilatation with mitral anomaly and hypoplastic left heart syndrome. We also reviewed CHDs in patients with a molecular diagnosis of Kabuki syndrome reported in the literature. In conclusion, a CHD is detected in 70% of patients with KMT2D (MLL2) pathogenic variants, most commonly left-sided obstructive lesions, including multiple left-sided obstructions similar to those observed in the spectrum of the Shone complex, and septal defects. Clinical management of Kabuki syndrome should include echocardiogram at the time of diagnosis, with particular attention to left-sided obstructive lesions and mitral anomalies, and annual monitoring for aortic arch dilatation. © 2017 Wiley Periodicals, Inc.

Inspection of surface defects for cladding tube with laser

International Nuclear Information System (INIS)

Senoo, Shigeo; Igarashi, Miyuki; Satoh, Masakazu; Miura, Makoto

1978-01-01

This paper presents the results of experiment on mechanizing the visual inspection of surface defects of cladding tubes and improving the reliability of surface defect inspection. Laser spot inspection method was adopted for this purpose. Since laser speckle pattern includes many informations about surface aspects, the method can be utilized as an effective means for detection or classification of the surface defects. Laser beam is focussed on cladding tube surfaces, and the reflected laser beam forms typical stellar speckle patterns on a screen. Sample cladding tubes are driven in longitudinal direction, and a photo-detector is placed at a position where secondary reflection will fall on the detector. Reflected laser beam from defect-free surfaces shows uniform distribution on the detector. When the incident focussed laser beam is directed to defects, the intensity of the reflected light is reduced. In the second method, laser beam is scanned by a rotating cube mirror. As the results of experiment, the typical patterns caused by defects were observed. It is clear that reflection patterns change with the kinds of defects. The sensitivity of defect detection decreases with the increase in laser beam diameter. Surface defect detection by intensity change was also tested. (Kato, T.)

Loss of Drosophila A-type lamin C initially causes tendon abnormality including disintegration of cytoskeleton and nuclear lamina in muscular defects.

Science.gov (United States)

Uchino, Ryo; Nonaka, Yu-Ki; Horigome, Tuneyoshi; Sugiyama, Shin; Furukawa, Kazuhiro

2013-01-01

Lamins are the major components of nuclear envelope architecture, being required for both the structural and informational roles of the nuclei. Mutations of lamins cause a spectrum of diseases in humans, including muscular dystrophy. We report here that the loss of the A-type lamin gene, lamin C in Drosophila resulted in pupal metamorphic lethality caused by tendon defects, matching the characteristics of human A-type lamin revealed by Emery-Dreifuss muscular dystrophy (EDMD). In tendon cells lacking lamin C activity, overall cell morphology was affected and organization of the spectraplakin family cytoskeletal protein Shortstop which is prominently expressed in tendon cells gradually disintegrated, notably around the nucleus and in a manner correlating well with the degradation of musculature. Furthermore, lamin C null mutants were efficiently rescued by restoring lamin C expression to shortstop-expressing cells, which include tendon cells but exclude skeletal muscle cells. Thus the critical function of A-type lamin C proteins in Drosophila musculature is to maintain proper function and morphology of tendon cells. Copyright © 2012 Elsevier Inc. All rights reserved.

Ploidy manipulation of the gametophyte, endosperm and sporophyte in nature and for crop improvement: a tribute to Professor Stanley J. Peloquin (1921-2008).

Science.gov (United States)

Ortiz, Rodomiro; Simon, Philipp; Jansky, Shelley; Stelly, David

2009-10-01

Emeritus Campbell-Bascom Professor Stanley J. Peloquin was an internationally renowned plant geneticist and breeder who made exceptional contributions to the quantity, quality and sustainable supply of food for the world from his innovative and extensive scientific contributions. For five decades, Dr Peloquin merged basic research in plant reproduction, cytology, cytogenetics, genetics, potato (Solanum tuberosum) improvement and education at the University of Wisconsin-Madison. Successive advances across these five decades redefined scientific comprehension of reproductive variation, its genetic control, genetic effects, evolutionary impact and utility for breeding. In concert with the International Potato Center (CIP), he and others translated the advances into application, resulting in large benefits on food production worldwide, exemplifying the importance of integrated innovative university research and graduate education to meet domestic and international needs. Dr Peloquin is known to plant breeders, geneticists, international agricultural economists and potato researchers for his enthusiastic and incisive contributions to genetic enhancement of potato using haploids, 2n gametes and wild Solanum species; for his pioneering work on potato cultivation through true seed; and as mentor of a new generation of plant breeders worldwide. The genetic enhancement of potato, the fourth most important food crop worldwide, benefited significantly from expanded germplasm utilization and advanced reproductive genetic knowledge, which he and co-workers, including many former students, systematically transformed into applied breeding methods. His research on plant sexual reproduction included subjects such as haploidization and polyploidization, self- and cross-incompatibility, cytoplasmic male sterility and restorer genes, gametophytic/sporophytic heterozygosity and male fertility, as well as endosperm dosages and seed development. By defining methods of half-tetrad analysis

Defects and diffusion in semiconductors XIV

CERN Document Server

Fisher, David J

2012-01-01

This 14th volume in the series covers the latest results in the field of Defects and Diffusion in Semiconductor. The issue also includes some original papers: An Experimental Study of the Thermal Properties of Modified 9Cr-1Mo Steel; Physico-Mechanical Properties of Sintered Iron-Silica Sand Nanoparticle Composites: A Preliminary Study; Defect and Dislocation Density Parameters of 5251 Al Alloy Using Positron Annihilation Lifetime Technique; A Novel Computational Strategy to Enhance the Ability of Elaborate Search by Entire Swarm to Find the Best Solution in Optimization of AMCs; Synthesis and

16 CFR 1115.4 - Defect.

Science.gov (United States)

2010-01-01

... Practices CONSUMER PRODUCT SAFETY COMMISSION CONSUMER PRODUCT SAFETY ACT REGULATIONS SUBSTANTIAL PRODUCT HAZARD REPORTS General Interpretation § 1115.4 Defect. Section 15(b)(2) of the CPSA requires every manufacturer (including an importer), distributor, and retailer of a consumer product who obtains information...

Strengthening of defected beam–column joints using CFRP

Directory of Open Access Journals (Sweden)

Mohamed H. Mahmoud

2014-01-01

Full Text Available This paper presents an experimental study for the structural performance of reinforced concrete (RC exterior beam–column joints rehabilitated using carbon-fiber-reinforced polymer (CFRP. The present experimental program consists of testing 10 half-scale specimens divided into three groups covering three possible defects in addition to an adequately detailed control specimen. The considered defects include the absence of the transverse reinforcement within the joint core, insufficient bond length for the beam main reinforcement and inadequate spliced implanted column on the joint. Three different strengthening schemes were used to rehabilitate the defected beam–column joints including externally bonded CFRP strips and sheets in addition to near surface mounted (NSM CFRP strips. The failure criteria including ultimate capacity, mode of failure, initial stiffness, ductility and the developed ultimate strain in the reinforcing steel and CFRP were considered and compared for each group for the control and the CFRP-strengthened specimens. The test results showed that the proposed CFRP strengthening configurations represented the best choice for strengthening the first two defects from the viewpoint of the studied failure criteria. On the other hand, the results of the third group showed that strengthening the joint using NSM strip technique enabled the specimen to outperform the structural performance of the control specimen while strengthening the joints using externally bonded CFRP strips and sheets failed to restore the strengthened joints capacity.

Strengthening of defected beam-column joints using CFRP.

Science.gov (United States)

Mahmoud, Mohamed H; Afefy, Hamdy M; Kassem, Nesreen M; Fawzy, Tarek M

2014-01-01

This paper presents an experimental study for the structural performance of reinforced concrete (RC) exterior beam-column joints rehabilitated using carbon-fiber-reinforced polymer (CFRP). The present experimental program consists of testing 10 half-scale specimens divided into three groups covering three possible defects in addition to an adequately detailed control specimen. The considered defects include the absence of the transverse reinforcement within the joint core, insufficient bond length for the beam main reinforcement and inadequate spliced implanted column on the joint. Three different strengthening schemes were used to rehabilitate the defected beam-column joints including externally bonded CFRP strips and sheets in addition to near surface mounted (NSM) CFRP strips. The failure criteria including ultimate capacity, mode of failure, initial stiffness, ductility and the developed ultimate strain in the reinforcing steel and CFRP were considered and compared for each group for the control and the CFRP-strengthened specimens. The test results showed that the proposed CFRP strengthening configurations represented the best choice for strengthening the first two defects from the viewpoint of the studied failure criteria. On the other hand, the results of the third group showed that strengthening the joint using NSM strip technique enabled the specimen to outperform the structural performance of the control specimen while strengthening the joints using externally bonded CFRP strips and sheets failed to restore the strengthened joints capacity.

Reactive evaporation of low-defect density hafnia

International Nuclear Information System (INIS)

Chow, R.; Falabella, S.; Loomis, G.E.; Rainer, F.; Stolz, C.J.; Kozlowski, M.R.

1993-01-01

Motivation for this work includes observations at Lawrence Livermore National Laboratory of a correlation between laser damage thresholds and both the absorption and the nodular-defect density of coatings. Activated oxygen is used to increase the metal-oxidation kinetics at the coated surface during electron-beam deposition. A series of hafnia layers are made with various conditions: two μ-wave configuations, two sources (hafnium and hafnia), and two reactive oxygen pressures. Laser damage thresholds (1064-nm, 10-ns pulses), absorption (at 511 nm), and nodular-defect densities from these coatings are reported. The damage thresholds are observed to increase as the absorption of the coatings decreases. However, no significant increase in damage thresholds are observed with the coatings made from a low nodular-defect density source material (hafnium). Hafnia coatings can be made from hafnium sources that have lower nodular-defect densities, lower absorption, and damage thresholds that are comparable with coatings made from a conventional hafnia source

Fibrous metaphyseal defects

International Nuclear Information System (INIS)

Ritschl, P.; Hajek, P.C.; Pechmann, U.

1989-01-01

Sixteen patients with fibrous metaphyseal defects were examined with both plain radiography and magnetic resonance (MR) imaging. Depending on the age of the fibrous metaphyseal defects, characteristic radiomorphologic changes were found which correlated well with MR images. Following intravenous Gadolinium-DTPA injection, fibrous metaphyseal defects invariably exhibited a hyperintense border and signal enhancement. (orig./GDG)

Defective TiO2 with oxygen vacancies: synthesis, properties and photocatalytic applications

Science.gov (United States)

Pan, Xiaoyang; Yang, Min-Quan; Fu, Xianzhi; Zhang, Nan; Xu, Yi-Jun

2013-04-01

Titanium dioxide (TiO2), as an important semiconductor metal oxide, has been widely investigated in the field of photocatalysis. The properties of TiO2, including its light absorption, charge transport and surface adsorption, are closely related to its defect disorder, which in turn plays a significant role in the photocatalytic performance of TiO2. Among all the defects identified in TiO2, oxygen vacancy is one of the most important and is supposed to be the prevalent defect in many metal oxides, which has been widely investigated both by theoretical calculations and experimental characterizations. Here, we give a short review on the existing strategies for the synthesis of defective TiO2 with oxygen vacancies, and the defect related properties of TiO2 including structural, electronic, optical, dissociative adsorption and reductive properties, which are intimately related to the photocatalytic performance of TiO2. In particular, photocatalytic applications with regard to defective TiO2 are outlined. In addition, we offer some perspectives on the challenge and new direction for future research in this field. We hope that this tutorial minireview would provide some useful contribution to the future design and fabrication of defective semiconductor-based nanomaterials for diverse photocatalytic applications.Titanium dioxide (TiO2), as an important semiconductor metal oxide, has been widely investigated in the field of photocatalysis. The properties of TiO2, including its light absorption, charge transport and surface adsorption, are closely related to its defect disorder, which in turn plays a significant role in the photocatalytic performance of TiO2. Among all the defects identified in TiO2, oxygen vacancy is one of the most important and is supposed to be the prevalent defect in many metal oxides, which has been widely investigated both by theoretical calculations and experimental characterizations. Here, we give a short review on the existing strategies for the

Extracting and identifying concrete structural defects in GPR images

Science.gov (United States)

Ye, Qiling; Jiao, Liangbao; Liu, Chuanxin; Cao, Xuehong; Huston, Dryver; Xia, Tian

2018-03-01

Traditionally most GPR data interpretations are performed manually. With the advancement of computing technologies, how to automate GPR data interpretation to achieve high efficiency and accuracy has become an active research subject. In this paper, analytical characterizations of major defects in concrete structures, including delamination, air void and moisture in GPR images, are performed. In the study, the image features of different defects are compared. Algorithms are developed for defect feature extraction and identification. For validations, both simulation results and field test data are utilized.

Defect detection based on extreme edge of defective region histogram

Directory of Open Access Journals (Sweden)

Zouhir Wakaf

2018-01-01

Full Text Available Automatic thresholding has been used by many applications in image processing and pattern recognition systems. Specific attention was given during inspection for quality control purposes in various industries like steel processing and textile manufacturing. Automatic thresholding problem has been addressed well by the commonly used Otsu method, which provides suitable results for thresholding images based on a histogram of bimodal distribution. However, the Otsu method fails when the histogram is unimodal or close to unimodal. Defects have different shapes and sizes, ranging from very small to large. The gray-level distributions of the image histogram can vary between unimodal and multimodal. Furthermore, Otsu-revised methods, like the valley-emphasis method and the background histogram mode extents, which overcome the drawbacks of the Otsu method, require preprocessing steps and fail to use the general threshold for multimodal defects. This study proposes a new automatic thresholding algorithm based on the acquisition of the defective region histogram and the selection of its extreme edge as the threshold value to segment all defective objects in the foreground from the image background. To evaluate the proposed defect-detection method, common standard images for experimentation were used. Experimental results of the proposed method show that the proposed method outperforms the current methods in terms of defect detection.

Freely-migrating defects: Their production and interaction with cascade remnants

International Nuclear Information System (INIS)

Rehn, L.E.; Wiedersich, H.

1991-05-01

Many microstructural changes that occur during irradiation are driven primarily by freely-migrating defects, i.e. those defects which escape from nascent cascades to migrate over distances that are large relative to typical cascade dimensions. Several measurements during irradiation at elevated temperatures have shown that the survival rate of freely-migrating defects decreases much more strongly with increasing primary recoil energy than does the survival rate for defects generated at liquid helium temperatures. For typical fission or fusion recoil spectra, and for heavy-ion bombardment, the fraction of defects that migrate long-distances is apparently only ∼1% of the calculated dpa. This small surviving fraction of freely-migrating defects results at least partially from additional intracascade recombination at elevated temperatures. However, cascade remnants, e.g., vacancy and interstitial clusters, also contribute by enhancing intercascade defect annihilation. A recently developed rate-theory approach is used to discuss the relative importance of intra- and intercascade recombination to the survival rate of freely-migrating defects. Within the validity of certain simplifying assumptions, the additional sink density provided by defect clusters produced directly within individual cascades can explain the difference between a defect survival rate of about 30% for low dose, low temperature irradiations with heavy ions, and a survival rate of only ∼1% for freely-migrating defects at elevated temperatures. The status of our current understanding of freely-migrating defects, including remaining unanswered questions, is also discussed. 33 refs., 5 figs

Synthetic Defects for Vibrothermography

Science.gov (United States)

Renshaw, Jeremy; Holland, Stephen D.; Thompson, R. Bruce; Eisenmann, David J.

2010-02-01

Synthetic defects are an important tool used for characterizing the performance of nondestructive evaluation techniques. Viscous material-filled synthetic defects were developed for use in vibrothermography (also known as sonic IR) as a tool to improve inspection accuracy and reliability. This paper describes how the heat-generation response of these VMF synthetic defects is similar to the response of real defects. It also shows how VMF defects can be applied to improve inspection accuracy for complex industrial parts and presents a study of their application in an aircraft engine stator vane.

[SOX2 defect and anophthalmia and microphthalmia].

Science.gov (United States)

Ye, Fu-xiang; Fan, Xian-qun

2012-11-01

As a severe congenital developmental disorder, anophthalmia and microphthalmia are usually accompanied with vision impairment and hypoevolutism of the orbit in the affected side. Many genes are involved in anophthalmia and microphthalmia, in which, SOX2 is an important one. The defect of SOX2 causes multiple system disorders, including anophthalmia and microphthalmia. We describe the relationship between the SOX2 defect and anophthalmia/microphthalmia, in order to offer some proposals for the differential diagnosis, treatment and research of anophthalmia and microphthalmia.

Mechanisms of Mitochondrial Defects in Gulf War Syndrome

Science.gov (United States)

2011-08-01

alanine. Additional abnormalities included a small fiber neuropathy in 35% (7/20) and cerebral folate defects. Cerebral folate deficiency (CFD) is...CoA ligase, ADP-forming, beta subunit (SUCLA2), Thymidine kinase 2, mitochondrial ( TK2 ), Thymidine phosphorylase (TYMP) may harbor mutations or that...syndrome patients have tissue deficiencies in CoQ10. This abnormality is observed in GWS patients. This defect can be treated with high levels of coenzyme

2012 Gordon Research Conference on Defects in Semiconductors - Formal Schedule and Speaker/Poster Program

Energy Technology Data Exchange (ETDEWEB)

Glaser, Evan [Naval Research Lab. (NRL), Washington, DC (United States)

2012-08-17

The meeting shall strive to develop and further the fundamental understanding of defects and their roles in the structural, electronic, optical, and magnetic properties of bulk, thin film, and nanoscale semiconductors and device structures. Point and extended defects will be addressed in a broad range of electronic materials of particular current interest, including wide bandgap semiconductors, metal-oxides, carbon-based semiconductors (e.g., diamond, graphene, etc.), organic semiconductors, photovoltaic/solar cell materials, and others of similar interest. This interest includes novel defect detection/imaging techniques and advanced defect computational methods.

Topological hierarchy matters — topological matters with superlattices of defects

International Nuclear Information System (INIS)

He Jing; Kou Su-Peng

2016-01-01

Topological insulators/superconductors are new states of quantum matter with metallic edge/surface states. In this paper, we review the defects effect in these topological states and study new types of topological matters — topological hierarchy matters. We find that both topological defects (quantized vortices) and non topological defects (vacancies) can induce topological mid-gap states in the topological hierarchy matters after considering the superlattice of defects. These topological mid-gap states have nontrivial topological properties, including the nonzero Chern number and the gapless edge states. Effective tight-binding models are obtained to describe the topological mid-gap states in the topological hierarchy matters. (topical review)

Covering the Dorsal Finger Defect with Reverse Cross Finger Flap

Directory of Open Access Journals (Sweden)

Kaan Gurbuz

2014-12-01

Full Text Available Reconstruction of finger extensor zone defects with or without tendon gaps still remains a challenge for surgeons. Although surgical treatments may differ, and range from the use of local, regional, to free flaps, the outcomes for all cases are not satisfactory. In this case report, we present a case of a 3rd finger extensor side crush injury including a defect of Dd (Digit Dorsal 1, Dd2 and Dd3 defects of extensor zones with tendon gap. Tendon gap was reconstructed using m. palmaris longus tendon graft and the defect was covered with reversed cross-finger flap (random pattern with good cosmetic and excellent functional results.

Microstructure modeling and crystal plasticity simulations for the evaluation of fatigue crack initiation in α-iron specimen including an elliptic defect

Energy Technology Data Exchange (ETDEWEB)

Briffod, Fabien, E-mail: briffod@rme.mm.t.u-tokyo.ac.jp; Shiraiwa, Takayuki; Enoki, Manabu

2017-05-17

In this study, fatigue crack initiation in pure α-iron is investigated through a microstructure-sensitive framework. At first, synthetic microstructures are modeled based on an anisotropic tessellation that accounts for the information of the grains morphology extracted from electron backscatter diffraction (EBSD) analysis. Low-cycle fatigue experiments under strain-controlled conditions are conducted in order to calibrate a crystal plasticity model and a J{sub 2} model including isotropic and kinematic hardening. A critical plane fatigue indicator parameter (FIP) based on the Tanaka-Mura model is then presented to evaluate the location and quantify the driving force for the formation of a crack. The FIP is averaged over several potential crack paths within each grain defined by the intersection between a given slip plane and the plane of the model thus accounting for both the lattice orientation and morphology of the grain. Several fatigue simulations at various stress amplitudes are conducted using a sub-modeling technique for the attribution of boundary conditions on the polycrystalline aggregate models including an elliptic defect. The influence of the microstructure attributes and stress level on the location and amplitude of the FIP are then quantified and discussed.

Simulations of defect spin qubits in piezoelectric semiconductors

Science.gov (United States)

Seo, Hosung

In recent years, remarkable advances have been reported in the development of defect spin qubits in semiconductors for solid-state quantum information science and quantum metrology. Promising spin qubits include the nitrogen-vacancy center in diamond, dopants in silicon, and the silicon vacancy and divacancy spins in silicon carbide. In this talk, I will highlight some of our recent efforts devoted to defect spin qubits in piezoelectric wide-gap semiconductors for potential applications in mechanical hybrid quantum systems. In particular, I will describe our recent combined theoretical and experimental study on remarkably robust quantum coherence found in the divancancy qubits in silicon carbide. We used a quantum bath model combined with a cluster expansion method to identify the microscopic mechanisms behind the unusually long coherence times of the divacancy spins in SiC. Our study indicates that developing spin qubits in complex crystals with multiple types of atom is a promising route to realize strongly coherent hybrid quantum systems. I will also discuss progress and challenges in computational design of new spin defects for use as qubits in piezoelectric crystals such as AlN and SiC, including a new defect design concept using large metal ion - vacancy complexes. Our first principles calculations include DFT computations using recently developed self-consistent hybrid density functional theory and large-scale many-body GW theory. This work was supported by the National Science Foundation (NSF) through the University of Chicago MRSEC under Award Number DMR-1420709.

Facts about Birth Defects

Science.gov (United States)

... label> Information For… Media Policy Makers Facts about Birth Defects Language: English (US) Español (Spanish) Recommend on ... having a baby born without a birth defect. Birth Defects Are Common Every 4 ½ minutes, a ...

Reduction in Defect Content of ODS Alloys

Energy Technology Data Exchange (ETDEWEB)

Ritherdon, J

2001-05-15

The work detailed within this report is a continuation of earlier work carried out under contract number 1DX-SY382V. The earlier work comprises a literature review of the sources and types of defects found principally in Fe-based ODS alloys as well as experimental work designed to identify defects in the prototype ODS-Fe{sub 3}Al alloy, deduce their origins and to recommend methods of defect reduction. The present work is an extension of the experimental work already reported and concentrates on means of reduction of defects already identified rather than the search for new defect types. This report also includes results gathered during powder separation trials, conducted by the University of Groningen, Netherlands and coordinated by the University of Liverpool, involving the separation of different metallic powders in terms of their differing densities. The scope and objectives of the present work were laid out in the technical proposal ''Reduction in Defect Content in ODS Alloys-III''. All the work proposed in the ''Statement of Work'' section of the technical proposal has been carried out and all work extra to the ''Statement of Work'' falls within the context of an ODS-Fe{sub 3}Al alloy of improved overall quality and potential creep performance in the consolidated form. The outturn of the experimental work performed is reported in the following sections.

Atomic structure of surface defects in alumina studied by dynamic force microscopy: strain-relief-, translation- and reflection-related boundaries, including their junctions

International Nuclear Information System (INIS)

Simon, G H; König, T; Heinke, L; Lichtenstein, L; Heyde, M; Freund, H-J

2011-01-01

We present an extensive atomic resolution frequency modulation dynamic force microscopy study of ultrathin aluminium oxide on a single crystalline NiAl(110) surface. One-dimensional surface defects produced by domain boundaries have been resolved. Images are presented for reflection domain boundaries (RDBs), four different types of antiphase domain boundaries, a nucleation-related translation domain boundary and also domain boundary junctions. New structures and aspects of the boundaries and their network are revealed and merged into a comprehensive picture of the defect arrangements. The alumina film also covers the substrate completely at the boundaries and their junctions and follows the structural building principles found in its unit cell. This encompasses square and rectangular groups of surface oxygen sites. The observed structural elements can be related to the electronic signature of the boundaries and therefore to the electronic defects associated with the boundaries. A coincidence site lattice predicted for the RDBs is in good agreement with experimental data. With Σ = 19 it can be considered to be of low-sigma type, which frequently coincides with special boundary properties. Images of asymmetric RDBs show points of good contact alternating with regions of nearly amorphous disorder in the oxygen sublattice. (paper)

Lithium niobate. Defects, photorefraction and ferroelectric switching

Energy Technology Data Exchange (ETDEWEB)

Volk, Tatyana [Russian Academy of Sciences, Inst. for Crystallography, Moscow (Russian Federation); Woehlecke, Manfred [Osnabrueck Univ. (Germany). Fachbereich Physik

2008-07-01

The book presents the current state of studies of point defects, both intrinsic and extrinsic (impurities, radiation centers, etc.), in LiNbO{sub 3}. The contribution of intrinsic defects to photoinduced charge transport, i.e. to the photorefraction, is explained. The photorefractive and optical properties of LiNbO{sub 3} crystals with different stoichiometry and of those doped with so-called ''optical-damage resistant'' impurities controlling the intrinsic defect structure are described in detail. Applications included are to the problem of non-erasable recording of photorefractive holograms in LiNbO{sub 3} and the current situation of studies in the ferroelectric switching and domain structure of LiNbO{sub 3}, as well as the creation of periodically-poled structures for the optical frequency conversion. (orig.)

Defects in dilute nitrides

International Nuclear Information System (INIS)

Chen, W.M.; Buyanova, I.A.; Tu, C.W.; Yonezu, H.

2005-01-01

We provide a brief review our recent results from optically detected magnetic resonance studies of grown-in non-radiative defects in dilute nitrides, i.e. Ga(In)NAs and Ga(Al,In)NP. Defect complexes involving intrinsic defects such as As Ga antisites and Ga i self interstitials were positively identified.Effects of growth conditions, chemical compositions and post-growth treatments on formation of the defects are closely examined. These grown-in defects are shown to play an important role in non-radiative carrier recombination and thus in degrading optical quality of the alloys, harmful to performance of potential optoelectronic and photonic devices based on these dilute nitrides. (author)

Genital and Urinary Tract Defects

Science.gov (United States)

... conditions > Genital and urinary tract defects Genital and urinary tract defects E-mail to a friend Please fill ... and extra fluids. What problems can genital and urinary tract defects cause? Genital and urinary tract defects affect ...

Prosthetic rehabilitation of large mid-facial defect with magnet-retained silicone prosthesis

Directory of Open Access Journals (Sweden)

Kirti Jajoo Shrivastava

2015-01-01

Full Text Available Rehabilitation of maxillofacial defect patients is a challenging task. The most common prosthetic treatment problem with such patients is, getting adequate retention, stability, and support. In cases of large maxillofacial defect, movement of the prosthesis is inevitable. The primary objectives in rehabilitating the maxillofacial defect patients are to restore the function of mastication, deglutition, speech, and to achieve normal orofacial appearance. This clinical report describes maxillofacial prosthetic rehabilitation of large midfacial defect including orbit along with its contents, zygoma and soft tissues including half of the nose, cheeks, upper lip of left side, accompanying postsurgical microstomia and orofacial communication, which resulted from severe fungal infection mucormycosis. The defect in this case was restored with magnet retained two piece maxillofacial prosthesis having hollow acrylic resin framework and an overlying silicone facial prosthesis. The retention of prosthesis was further enhanced with the use of spectacles. This type of combination prosthesis enhanced the cosmesis and functional acceptability of prosthesis.

Thermal buckling behavior of defective CNTs under pre-load: A molecular dynamics study.

Science.gov (United States)

Mehralian, Fahimeh; Tadi Beni, Yaghoub; Kiani, Yaser

2017-05-01

Current study is concentrated on the extraordinary properties of defective carbon nanotubes (CNTs). The role of vacancy defects in thermal buckling response of precompressed CNTs is explored via molecular dynamics (MD) simulations. Defective CNTs are initially compressed at a certain ratio of their critical buckling strain and then undergo a uniform temperature rise. Comprehensive study is implemented on both armchair and zigzag CNTs with different vacancy defects including monovacancy, symmetric bivacancy and asymmetric bivacancy. The results reveal that defects have a pronounced impact on the buckling behavior of CNTs; interestingly, defective CNTs under compressive pre-load show higher resistance to thermal buckling than pristine ones. In the following, the buckling response of defective CNTs is shown to be dependent on the vacancy defects, location of defects and chirality. Copyright © 2017 Elsevier Inc. All rights reserved.

Point defects and defect clusters examined on the basis of some fundamental experiments

International Nuclear Information System (INIS)

Zuppiroli, L.

1975-01-01

On progressing from the centre of the defect to the surface the theoretical approach to a point defect passes from electronic theories to elastic theory. Experiments by which the point defect can be observed fall into two categories. Those which detect long-range effects: measurement of dimensional variations in the sample; measurement of the mean crystal parameter variation; elastic X-ray scattering near the nodes of the reciprocal lattice (Huang scattering). Those which detect more local effects: low-temperature resistivity measurement; positron capture and annihilation; local scattering far from the reciprocal lattice nodes. Experiments involving both short and long-range effects can always be found. This is the case for example with the dechanneling of α particles by defects. Certain of the experimental methods quoted above apply also to the study of point defect clusters. These methods are illustrated by some of their most striking results which over the last twenty years have refined our knowledge of point defects and defect clusters: length and crystal parameter measurements; diffuse X-ray scattering; low-temperature resistivity measurements; ion emission microscopy; electron microscopy; elastoresistivity [fr

Birth Defects (For Parents)

Science.gov (United States)

... Staying Safe Videos for Educators Search English Español Birth Defects KidsHealth / For Parents / Birth Defects What's in ... Prevented? Print en español Anomalías congénitas What Are Birth Defects? While still in the womb, some babies ...

International conference on defects in insulating crystals

International Nuclear Information System (INIS)

1977-01-01

Short summaries of conference papers are presented. Some of the conference topics included transport properties, defect levels, superionic conductors, radiation effects, John-Teller effect, electron-lattice interactions, and relaxed excited states

Study of defect characteristics essential for NDT testing methods ET, UT and RT

International Nuclear Information System (INIS)

Wirdelius, H.; Oesterberg, Elena

2000-10-01

This paper presents results from a literature review of defect characteristics essential for nondestructive testing (NDT). Most of the major NDT methods are included in the study - ultrasonic testing (UT), radiography (RT) and eddy current testing (ET). The study was performed by means of searching in scientific databases, technical journals, conference proceedings etc. Mainly the following databases were used: CHANS (Chalmers database), INSPEC, NTIS, Ei Compendex, World Surface Coating Abs, METADEX, JICST-Eplus, Aerospace database, Pascal, Eng Materials, SciSearch and Weldasearch. It is concluded that for eddy current testing, the defect geometry, the defect size and the defect orientation influence the outcome signal. A number of investigations address the relationships between the defect parameters like defect depth, length and width and the outcome signal parameters like amplitude, phase and signal shape. Also the phenomena of the electrical contacts between the defect surfaces (for a crack) was studied. Defect parameters that are essential to the quality of ultrasonic testing are defect position in the object (includes the depth), orientation, size, crack surface roughness, closure and tip radius. This investigation has been focused on those parameters that are not that easy to reconstruct and only briefly discussed the influence on the signal response due to defect position, orientation and size. When it comes to radiographic techniques, the most important defect related parameters that influence the quality are the difference in radio opacity of the specimen and defect and the angle between the volumetric extension of the defect and the direction of projection. The defect gape and the morphology of the crack are also very essential parameters. A very simple model of the detectability as a function of depth, width and misorientation (angle to the radiation beam) has been validated and to some extent also verified in a number of papers. Even for defects with

Interatomic potentials and the simulation of lattice defects in metals

International Nuclear Information System (INIS)

Heugten, W.F.W.M. van.

1979-01-01

The computer simulation technique is applied to investigate the properties of point defects and line defects in metals. For that purpose crystallites are constructed in which these defects are simulated. In the case of line defects (dislocations) the initial positions of the atoms, surrounding the dislocations, are determined using the elastic theory of anisotropic media. Hereafter the atoms in such crystallites are allowed to relax to there minimum potential energy positions under the influence of the interatomic forces. These forces are derived from interatomic interaction potentials. These potentials are together with the boundary conditions of the simulated crystallite the main input data in these computer simulation models. The metals considered include molybdenum, tungsten and tantalum. (Auth.)

Variations in first principles calculated defect energies in GaAs and ...

Indian Academy of Sciences (India)

Keywords. Ab initio calculations; semi-insulating GaAs; point defects. ... We are focusing on gallium arsenide. .... gallium vacancy in S & L, P et al and N & Z will exist in triple ... gallium antisite defect that include relaxation, a negative. U-effect is ...

Proceedings of defect engineering in semiconductor growth, processing and device technology

International Nuclear Information System (INIS)

Ashok, S.; Chevallier, J.; Sumino, K.; Weber, E.

1992-01-01

This volume results from a symposium that was part of the 1992 Spring Meeting of the Materials Research Society, held in San Francisco from April 26 to May 1, 1992. The symposium, entitled Defect Engineering in Semiconductor Growth, Processing and Device Technology, was the first of its kind at MRS and brought together academic and industrial researchers with varying perspectives on defects in semiconductors. Its aim was to go beyond defect control, and focus instead on deliberate and controlled introduction and manipulation of defects in order to engineer some desired properties in semiconductor materials and devices. While the concept of defect engineering has at least a vague perception in techniques such as impurity/defect gettering and the use of the EL2 level in GaAs, more extensive as well as subtle uses of defects are emerging to augment the field. This symposium was intended principally to encourage creative new applications of defects in all aspects of semiconductor technology. The organization of this proceedings volume closely follows the topics around which the sessions were built. The papers on grown-in defects in bulk crystals deal with overviews of intrinsic and impurity-related defects, their influence on electrical, optical and mechanical properties, as well as the use of impurities to arrest certain types of defects during growth and defects to control growth. The issues addressed by the papers on defects in thin films include impurity and stoichiometry control, defects created by plasmas and the use of electron/ion irradiation for doping control

Strip defect recognition in electrical tests of silicon microstrip sensors

Energy Technology Data Exchange (ETDEWEB)

Valentan, Manfred, E-mail: valentan@mpp.mpg.de

2017-02-11

This contribution describes the measurement procedure and data analysis of AC-coupled double-sided silicon microstrip sensors with polysilicon resistor biasing. The most thorough test of a strip sensor is an electrical measurement of all strips of the sensor; the measured observables include e.g. the strip's current and the coupling capacitance. These measurements are performed to find defective strips, e.g. broken capacitors (pinholes) or implant shorts between two adjacent strips. When a strip has a defect, its observables will show a deviation from the “typical value”. To recognize and quantify certain defects, it is necessary to determine these typical values, i.e. the values the observables would have without the defect. As a novel approach, local least-median-of-squares linear fits are applied to determine these “would-be” values of the observables. A least-median-of-squares fit is robust against outliers, i.e. it ignores the observable values of defective strips. Knowing the typical values allows to recognize, distinguish and quantify a whole range of strip defects. This contribution explains how the various defects appear in the data and in which order the defects can be recognized. The method has been used to find strip defects on 30 double-sided trapezoidal microstrip sensors for the Belle II Silicon Vertex Detector, which have been measured at the Institute of High Energy Physics, Vienna (Austria).

Epigenetic differentiation persists after male gametogenesis in natural populations of the perennial herb Helleborus foetidus (Ranunculaceae).

Science.gov (United States)

Herrera, Carlos M; Medrano, Mónica; Bazaga, Pilar

2013-01-01

Despite the importance of assessing the stability of epigenetic variation in non-model organisms living in real-world scenarios, no studies have been conducted on the transgenerational persistence of epigenetic structure in wild plant populations. This gap in knowledge is hindering progress in the interpretation of natural epigenetic variation. By applying the methylation-sensitive amplified fragment length polymorphism (MSAP) technique to paired plant-pollen (i.e., sporophyte-male gametophyte) DNA samples, and then comparing methylation patterns and epigenetic population differentiation in sporophytes and their descendant gametophytes, we investigated transgenerational constancy of epigenetic structure in three populations of the perennial herb Helleborus foetidus (Ranunculaceae). Single-locus and multilocus analyses revealed extensive epigenetic differentiation between sporophyte populations. Locus-by-locus comparisons of methylation status in individual sporophytes and descendant gametophytes showed that ~75% of epigenetic markers persisted unchanged through gametogenesis. In spite of some epigenetic reorganization taking place during gametogenesis, multilocus epigenetic differentiation between sporophyte populations was preserved in the subsequent gametophyte stage. In addition to illustrating the efficacy of applying the MSAP technique to paired plant-pollen DNA samples to investigate epigenetic gametic inheritance in wild plants, this paper suggests that epigenetic differentiation between adult plant populations of H. foetidus is likely to persist across generations.

Epigenetic differentiation persists after male gametogenesis in natural populations of the perennial herb Helleborus foetidus (Ranunculaceae.

Directory of Open Access Journals (Sweden)

Carlos M Herrera

Full Text Available Despite the importance of assessing the stability of epigenetic variation in non-model organisms living in real-world scenarios, no studies have been conducted on the transgenerational persistence of epigenetic structure in wild plant populations. This gap in knowledge is hindering progress in the interpretation of natural epigenetic variation. By applying the methylation-sensitive amplified fragment length polymorphism (MSAP technique to paired plant-pollen (i.e., sporophyte-male gametophyte DNA samples, and then comparing methylation patterns and epigenetic population differentiation in sporophytes and their descendant gametophytes, we investigated transgenerational constancy of epigenetic structure in three populations of the perennial herb Helleborus foetidus (Ranunculaceae. Single-locus and multilocus analyses revealed extensive epigenetic differentiation between sporophyte populations. Locus-by-locus comparisons of methylation status in individual sporophytes and descendant gametophytes showed that ~75% of epigenetic markers persisted unchanged through gametogenesis. In spite of some epigenetic reorganization taking place during gametogenesis, multilocus epigenetic differentiation between sporophyte populations was preserved in the subsequent gametophyte stage. In addition to illustrating the efficacy of applying the MSAP technique to paired plant-pollen DNA samples to investigate epigenetic gametic inheritance in wild plants, this paper suggests that epigenetic differentiation between adult plant populations of H. foetidus is likely to persist across generations.

International conference on defects in insulating crystals

Energy Technology Data Exchange (ETDEWEB)

1977-01-01

Short summaries of conference papers are presented. Some of the conference topics included transport properties, defect levels, superionic conductors, radiation effects, John-Teller effect, electron-lattice interactions, and relaxed excited states. (SDF)

Formation of topological defects

International Nuclear Information System (INIS)

Vachaspati, T.

1991-01-01

We consider the formation of point and line topological defects (monopoles and strings) from a general point of view by allowing the probability of formation of a defect to vary. To investigate the statistical properties of the defects at formation we give qualitative arguments that are independent of any particular model in which such defects occur. These arguments are substantiated by numerical results in the case of strings and for monopoles in two dimensions. We find that the network of strings at formation undergoes a transition at a certain critical density below which there are no infinite strings and the closed-string (loop) distribution is exponentially suppressed at large lengths. The results are contrasted with the results of statistical arguments applied to a box of strings in dynamical equilibrium. We argue that if point defects were to form with smaller probability, the distance between monopoles and antimonopoles would decrease while the monopole-to-monopole distance would increase. We find that monopoles are always paired with antimonopoles but the pairing becomes clean only when the number density of defects is small. A similar reasoning would also apply to other defects

Photographic guide of selected external defect indicators and associated internal defects in sugar maple

Science.gov (United States)

Everette D. Rast; John A. Beaton; David L. Sonderman

1991-01-01

To properly classify or grade logs or trees, one must be able to correctly identify defect indicators and assess the effect of the underlying defect on possible end products. This guide assists the individual in identifying the surface defect indicator and shows the progressive stages of the defect throughout its development for sugar maple. Eleven types of external...

Photographic guide of selected external defect indicators and associated internal defects in yellow-poplar

Science.gov (United States)

Everette D. Rast; John A. Beaton; David L. Sonderman

1991-01-01

To properly classify or grade logs or trees, one must be able to correctly identify defect indicators and assess the effect of the underlying defect on possible end products. This guide assists the individual in identifying the surface defect indicator and shows the progressive stages of the defect throughout its development for yellow-poplar. Twelve types of external...

Photographic guide of selected external defect indicators and associated internal defects in yellow birch

Science.gov (United States)

Everette D. Rast; John A. Beaton; David L. Sonderman

1991-01-01

To properly classify or grade logs or trees, one must be able to correctly identify defect indicators and assess the effect of the underlying defect on possible end products. This guide assists the individual in identifying the surface defect indicator and shows the progressive stages of the defect throughout its development for yellow birch. Eleven types of external...

Sirenomelia: A Multi-systemic Polytopic Field Defect with Ongoing Controversies.

Science.gov (United States)

Boer, Lucas L; Morava, Eva; Klein, Willemijn M; Schepens-Franke, Annelieke N; Oostra, Roelof Jan

2017-06-01

The most impressive phenotypic appearance of sirenomelia is the presence of a 180°-rotated, axially positioned, single lower limb. Associated gastrointestinal and genitourinary anomalies are almost always present. This rare anomaly is still the subject of ongoing controversies concerning its nosology, pathogenesis, and possible genetic etiology. Sirenomelia can be part of a syndromic continuum, overlapping with other complex conditions including caudal dysgenesis and VATER/VACTERL/VACTERL-H associations, which could all be part of a heterogeneous spectrum, and originate from an early defect in blastogenesis. It is imaginable that different "primary field defects," whether or not genetically based, induce a spectrum of caudal malformations. In the current study, we review the contemporary hypotheses and conceptual approaches regarding the etiology and pathogenesis of sirenomelia, especially in the context of concomitant conditions. To expand on the latter, we included the external and internal dysmorphology of one third trimester sirenomelic fetus from our anatomical museum collection, in which multiple concomitant but discordant anomalies were observed compared with classic sirenomelia, and was diagnosed as VACTERL-H association with sirenomelia. Birth Defects Research 109:791-804, 2017. © 2017 The Authors. Birth Defects Research Published by Wiley Periodicals, Inc. © 2017 The Authors. Birth Defects Research Published by Wiley Periodicals, Inc.

Nucleation of voids and other irradiation-produced defect aggregates

International Nuclear Information System (INIS)

Wiedersich, H.; Katz, J.L.

1976-01-01

The nucleation of defect clusters in crystalline solids from radiation-produced defects is different from the usual nucleation processes in one important aspect: the condensing defects, interstitial atoms and vacancies, can mutually annihilate and are thus similar to matter and antimatter. The nucleation process is described as the simultaneous reaction of vacancies and interstitials (and gas atoms if present) with embryos of all sizes. The reaction rates for acquisition of point defects (and gas atoms) are calculated from their respective jump frequencies and concentrations in the supersaturated system. The reaction rates for emission of point defects are derived from the free energies of the defect clusters in the thermodynamic equilibrium system, i.e., the system without excess point defects. This procedure differs from that used in conventional nucleation theory and permits the inclusion of the ''antimatter'' defect into the set of reaction-rate equations in a straightforward manner. The method is applied to steady-state nucleation, during irradiation, of both dislocation loops and voids in the absence and in the presence of immobile and mobile gas. The predictions of the nucleation theory are shown to be in qualitative agreement with experimental observations, e.g., void densities increase with increasing displacement rates; gases such as helium enhance void nucleation; at low displacement rates and at high temperatures the presence of gas is essential to void formation. For quantitative predictions, the theory must be extended to include the termination of nucleation

Tetralogy of Fallot with restrictive ventricular septal defect by accessory tricuspid leaflet tissue

OpenAIRE

Mahipat Raj Soni; Deepak A. Bohara; Ajay U. Mahajan; Pratap J. Nathani

2012-01-01

In tetralogy of Fallot septal defect is usually large because of malalignment of outlet septum, restrictive defect has been reported rarely. We present a case of tetralogy of Fallot with accessory tricuspid leaflet tissue restricting ventricular septal defect. The report includes echocardiographic and catheter images of this rare presentation of tetralogy of Fallot.

Automated defect spatial signature analysis for semiconductor manufacturing process

Science.gov (United States)

Tobin, Jr., Kenneth W.; Gleason, Shaun S.; Karnowski, Thomas P.; Sari-Sarraf, Hamed

1999-01-01

An apparatus and method for performing automated defect spatial signature alysis on a data set representing defect coordinates and wafer processing information includes categorizing data from the data set into a plurality of high level categories, classifying the categorized data contained in each high level category into user-labeled signature events, and correlating the categorized, classified signature events to a present or incipient anomalous process condition.

Entanglement entropy in integrable field theories with line defects II. Non-topological defect

Science.gov (United States)

Jiang, Yunfeng

2017-08-01

This is the second part of two papers where we study the effect of integrable line defects on bipartite entanglement entropy in integrable field theories. In this paper, we consider non-topological line defects in Ising field theory. We derive an infinite series expression for the entanglement entropy and show that both the UV and IR limits of the bulk entanglement entropy are modified by the line defect. In the UV limit, we give an infinite series expression for the coefficient in front of the logarithmic divergence and the exact defect g-function. By tuning the defect to be purely transmissive and reflective, we recover correctly the entanglement entropy of the bulk and with integrable boundary respectively.

High defect stage, contralateral defects, and poor flexibility are negative predictive factors of bone union in pediatric and adolescent athletes with spondylolysis.

Science.gov (United States)

Yamazaki, Kazufumi; Kota, Shintaro; Oikawa, Daisuke; Suzuki, Yoshiji

2018-01-01

To identify predisposition to spondylolysis and physical characteristics associated with "bone union" following conservative spondylolysis treatment among pediatric and adolescent athletes. We retrospectively analyzed pediatric and adolescent athletes with spondylolysis who underwent conservative treatment and rehabilitation for three or more consecutive months following sports activity cessation. Patients with terminal spondylolysis or who did not discontinue sports activities were excluded. We compared physical fitness factors in the union and nonunion groups and examined the association between bone union and spondylolysis severity by logistic regression analysis. Of 183 patients with spondylolysis who underwent rehabilitation over a four-year period, 127 patients with 227 defects were included in the final analysis. Bone union was achieved in 66.5% (151/227) of the pars interarticularis defects and 70.1% (89/127) of the patients. On multivariate analysis, stage of pars interarticularis defect (odds ratio [OR], 0.26;p = 0.0027), stage of contralateral pars interarticularis defect (OR, 0.51;p = 0.00026), and straight leg-raising test (OR, 1.06;p = 0.028) were significantly associated with bone union. High defect stage, stage of the contralateral pars interarticularis defect, and poor flexibility were negative prognostic factors of bone healing in athletes with spondylolysis. J. Med. Invest. 65:126-130, February, 2018.

Issues in first-principles calculations for defects in semiconductors and oxides

International Nuclear Information System (INIS)

Nieminen, Risto M

2009-01-01

Recent advances in density-functional theory (DFT) calculations of defect electronic properties in semiconductors and insulators are discussed. In particular, two issues are addressed: the band-gap underestimation of standard density-functional methods with its harmful consequences for the positioning of defect-related levels in the band-gap region, and the slow convergence of calculated defect properties when the periodic supercell approach is used. Systematic remedies for both of these deficiencies are now available, and are being implemented in the context of popular DFT codes. This should help in improving the parameter-free accuracy and thus the predictive power of the methods to enable unambiguous explanation of defect-related experimental observations. These include not only the various fingerprint spectroscopies for defects but also their thermochemistry and dynamics, i.e. the temperature-dependent concentration and diffusivities of defects under various doping conditions and in different stoichiometries

Natural defects and defects created by ionic implantation in zinc tellurium

International Nuclear Information System (INIS)

Roche, J.P.; Dupuy, M.; Pfister, J.C.

1977-01-01

Various defects have been studied in ZnTe crystals by transmission electron microscope and by scanning electron microscope in cathodo-luminescence mode: grain boundaries, sub-grain boundaries, twins. Ionic implants of boron (100 keV - 2x10 14 and 10 15 ions cm -2 ) were made on these crystals followed by isochrone annealing (30 minutes) of zinc under partial pressure at 550, 650 and 750 0 C. The nature of the defects was determined by transmission electron microscope: these are interstitial loops (b=1/3 ) the size of which varies between 20 A (non-annealed sample) and 180A (annealed at 750 0 C). The transmission electron microscope was also used to make concentration profiles of defects depending on depth. It is found that for the same implant (2x10 14 ions.cm -2 ), the defect peak moves towards the exterior of the crystal as the annealing temperature rises (400 - 1000 and 7000 A for the three annealings). These results are explained from a model which allows for the coalescence of defects and considers the surface of the sample as being the principal source of vacancies. During the annealings, the migration of vacancies brings about the gradual annihilation of the implant defects. The adjustment of certain calculation parameters on the computer result in giving 2 eV as energy value for the formation of vacancies [fr

Surface defect detection in tiling Industries using digital image processing methods: analysis and evaluation.

Science.gov (United States)

Karimi, Mohammad H; Asemani, Davud

2014-05-01

Ceramic and tile industries should indispensably include a grading stage to quantify the quality of products. Actually, human control systems are often used for grading purposes. An automatic grading system is essential to enhance the quality control and marketing of the products. Since there generally exist six different types of defects originating from various stages of tile manufacturing lines with distinct textures and morphologies, many image processing techniques have been proposed for defect detection. In this paper, a survey has been made on the pattern recognition and image processing algorithms which have been used to detect surface defects. Each method appears to be limited for detecting some subgroup of defects. The detection techniques may be divided into three main groups: statistical pattern recognition, feature vector extraction and texture/image classification. The methods such as wavelet transform, filtering, morphology and contourlet transform are more effective for pre-processing tasks. Others including statistical methods, neural networks and model-based algorithms can be applied to extract the surface defects. Although, statistical methods are often appropriate for identification of large defects such as Spots, but techniques such as wavelet processing provide an acceptable response for detection of small defects such as Pinhole. A thorough survey is made in this paper on the existing algorithms in each subgroup. Also, the evaluation parameters are discussed including supervised and unsupervised parameters. Using various performance parameters, different defect detection algorithms are compared and evaluated. Copyright © 2013 ISA. Published by Elsevier Ltd. All rights reserved.

Finite volume form factors in the presence of integrable defects

International Nuclear Information System (INIS)

Bajnok, Z.; Buccheri, F.; Hollo, L.; Konczer, J.; Takacs, G.

2014-01-01

We developed the theory of finite volume form factors in the presence of integrable defects. These finite volume form factors are expressed in terms of the infinite volume form factors and the finite volume density of states and incorporate all polynomial corrections in the inverse of the volume. We tested our results, in the defect Lee–Yang model, against numerical data obtained by truncated conformal space approach (TCSA), which we improved by renormalization group methods adopted to the defect case. To perform these checks we determined the infinite volume defect form factors in the Lee–Yang model exactly, including their vacuum expectation values. We used these data to calculate the two point functions, which we compared, at short distance, to defect CFT. We also derived explicit expressions for the exact finite volume one point functions, which we checked numerically. In all of these comparisons excellent agreement was found

Eddy Current Testing for Detecting Small Defects in Thin Films

Science.gov (United States)

Obeid, Simon; Tranjan, Farid M.; Dogaru, Teodor

2007-03-01

Presented here is a technique of using Eddy Current based Giant Magneto-Resistance sensor (GMR) to detect surface and sub-layered minute defects in thin films. For surface crack detection, a measurement was performed on a copper metallization of 5-10 microns thick. It was done by scanning the GMR sensor on the surface of the wafer that had two scratches of 0.2 mm, and 2.5 mm in length respectively. In another experiment, metal coatings were deposited over the layers containing five defects with known lengths such that the defects were invisible from the surface. The limit of detection (resolution), in terms of defect size, of the GMR high-resolution Eddy Current probe was studied using this sample. Applications of Eddy Current testing include detecting defects in thin film metallic layers, and quality control of metallization layers on silicon wafers for integrated circuits manufacturing.

Clinical concepts for regenerative therapy in intrabony defects.

Science.gov (United States)

Cortellini, Pierpaolo; Tonetti, Maurizio S

2015-06-01

Evidence indicates that periodontal regeneration is an efficacious and predictable procedure for the treatment of isolated and multiple intrabony defects. Meta-analyses from systematic reviews indicate an added benefit, in terms of clinical attachment level gain, when demineralized freeze-dried bone allograft, barrier membranes and active biologic products/compounds are applied in addition to open flap debridement. On the other hand, a consistent amount of variability of the outcomes is evident among different studies and within the experimental population of each study. This variability is explained, at least in part, by different patient and defect characteristics. Patient-related factors include smoking habit, compliance with home oral hygiene and residual inflammation after cause-related therapy. Defect-associated factors include defect depth and radiographic angle, the number of residual bony walls, pocket depth and the degree of hypermobility. In addition, surgical-related variables, such as surgical skill, clinical experience and knowledge, and application of the different regenerative materials, have a significant impact on clinical outcomes. This paper presents a strategy to optimize the clinical outcomes of periodontal regeneration. The surgical design of the flap, the use of different regenerative materials and the application of appropriate passive sutures are discussed in this review along with the scientific foundations. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Computer experiment studies on mechanisms for irradiation induced defect production and annealing processes. Final report

International Nuclear Information System (INIS)

Beeler, J.R. Jr.; Beeler, M.F.

1979-06-01

This research is based on pair potentials used in the Brookhaven work. It extends their use in defect production simulations to the 5 MeV range and characterizes the short term annealing of the primary defect states. Defect properties and interactions are studied. Defect interactions include carbon, helium, and misfit metallic substitutional impurity interactions with vacancy and interstitial defects as well as vacancy-vacancy, interstitial-interstitial and vacancy-interstitial interactions

Computer experiment studies on mechanisms for irradiation induced defect production and annealing processes. Final report

Energy Technology Data Exchange (ETDEWEB)

Beeler, J.R. Jr.; Beeler, M.F.

1979-06-01

This research is based on pair potentials used in the Brookhaven work. It extends their use in defect production simulations to the 5 MeV range and characterizes the short term annealing of the primary defect states. Defect properties and interactions are studied. Defect interactions include carbon, helium, and misfit metallic substitutional impurity interactions with vacancy and interstitial defects as well as vacancy-vacancy, interstitial-interstitial and vacancy-interstitial interactions. (FS)

Genetic and experimental evidence for a mixed-age, mixed-origin bank of kelp microscopic stages in southern California.

Science.gov (United States)

Carney, Laura T; Bohonak, Andrew J; Edwards, Matthew S; Alberto, Filipe

2013-09-01

Laboratory studies have demonstrated that the microscopic stages of kelps can rapidly resume development from a delayed state. Like terrestrial seeds or aquatic resting eggs, banks of delayed kelp stages may supplement population recovery after periods of stress, playing an important role for kelp populations that experience adult sporophyte absences due to seasonal or interannual disturbances. We found that removing the microscopic stages from natural rock substratum could prevent the appearance of juvenile kelp sporophytes for three months and the establishment of a diverse kelp assemblage for over four months within a southern California kelp forest. Juveniles were observed within one month in plots where microscopic stages were left intact, which may confer an advantage for the resulting sporophytes as they attain larger sizes before later recruiting neighbors. Microsatellite diversity was high (expected heterozygosity HE approximately 0.9) for juveniles and adults within our sites. Using a microsatellite-based parentage analysis for the dominant kelp, Macrocystis pyrifera, we estimated that a portion of the new M. pyrifera sporophyte recruits had originated from their parents at least seven months after their parents had disappeared. Similar delay durations have been demonstrated in recent laboratory studies. Additionally, our results suggest that zoospore dispersal distances > 50 m may be supported by including additional microsatellite loci in the analysis. We propose a mixed-age and, potentially, a mixed-origin bank of M. pyrifera gametophytes promotes maximal genetic diversity in recovering populations and reduces population genetic subdivision and self-fertilization rates for intact populations by promoting the survival of zoospores dispersed > 10 m and during inhospitable environmental conditions.

Modeling the relationships among internal defect features and external Appalachian hardwood log defect indicators

Science.gov (United States)

R. Edward. Thomas

2009-01-01

As a hardwood tree grows and develops, surface defects such as branch stubs and wounds are overgrown. Evidence of these defects remain on the log surface for decades and in many instances for the life of the tree. As the tree grows the defect is encapsulated or grown over by new wood. During this process the appearance of the defect in the tree's bark changes. The...

Behavior of duplex stainless steel casting defects under mechanical loadings

Energy Technology Data Exchange (ETDEWEB)

Jayet-Gendrot, S [Electricite de France, 77 - Moret-sur-Loing (France). Dept. of Materials Study; Gilles, P; Migne, C [Societe Franco-Americaine de Constructions Atomiques (FRAMATOME), 92 - Paris-La-Defense (France)

1997-04-01

Several components in the primary circuit of pressurized water reactors are made of cast duplex stainless steels. This material contains small casting defects, mainly shrinkage cavities, due to the manufacturing process. In safety analyses, the structural integrity of the components is studied. In order to assess the real severity of the casting defects under mechanical loadings, an experimental program was carried out. It consisted of testing, under both cyclic and monotonic solicitations, three-point bend specimens containing either a natural defect (in the form of a localized cluster of cavities) or a machined notch having the dimensions of the cluster`s envelope. The tests are analyzed in order to develop a method that takes into account the behavior of castings defects in a more realistic fashion than by an envelope crack. Various approaches are investigated, including the search of equivalent defects or of criteria based on continuum mechanics concepts, and compared with literature data. This study shows the conservatism of current safety analyses in modelling casting defects by envelope semi-elliptical cracks and contributes to the development of alternative approaches. (author) 18 refs.

Holographic Chern-Simons defects

International Nuclear Information System (INIS)

Fujita, Mitsutoshi; Melby-Thompson, Charles M.; Meyer, René; Sugimoto, Shigeki

2016-01-01

We study SU(N) Yang-Mills-Chern-Simons theory in the presence of defects that shift the Chern-Simons level from a holographic point of view by embedding the system in string theory. The model is a D3-D7 system in Type IIB string theory, whose gravity dual is given by the AdS soliton background with probe D7 branes attaching to the AdS boundary along the defects. We holographically renormalize the free energy of the defect system with sources, from which we obtain the correlation functions for certain operators naturally associated to these defects. We find interesting phase transitions when the separation of the defects as well as the temperature are varied. We also discuss some implications for the Fractional Quantum Hall Effect and for 2-dimensional QCD.

Ferromagnetically coupled local moments along an extended line defect in graphene

Science.gov (United States)

White, Carter T.; Vasudevan, Smitha; Gunlycke, Daniel

2011-03-01

Recently an extended line defect was observed composed of octagonal and pentagonal carbon rings embedded in a graphene sheet [Nat. Nanotech. 5, 326 (2010)]. We report results of studies we have made of this defect using both first-principles and semi-empirical methods. Two types of boundary-localized states arising from the defect are identified. The first (second) type has eigenstates with wavefunctions that are anti- symmetric (symmetric) with respect to a mirror plane that is perpendicular to the graphene sheet and passes through the line defect center line. The boundary-localized anti-symmetric states are shown to be intimately connected to the zigzag edge states of semi-infinite graphene. They exhibit little dispersion along the defect line and lie close to the Fermi level giving rise to a spontaneous spin polarization along the defect once electron-electron interactions are included at the level of a mean field approximation to a Hubbard Model. Within this approach, symmetry requires that the principal moments couple ferromagnetically both along and across the line defect leading to approximately 2/3 more up than down spin electrons per defect repeat unit. This work was supported by ONR, directly and through NRL.

Mean Glenoid Defect Size and Location Associated With Anterior Shoulder Instability

Science.gov (United States)

Gottschalk, Lionel J.; Bois, Aaron J.; Shelby, Marcus A.; Miniaci, Anthony; Jones, Morgan H.

2017-01-01

Background: There is a strong correlation between glenoid defect size and recurrent anterior shoulder instability. A better understanding of glenoid defects could lead to improved treatments and outcomes. Purpose: To (1) determine the rate of reporting numeric measurements for glenoid defect size, (2) determine the consistency of glenoid defect size and location reported within the literature, (3) define the typical size and location of glenoid defects, and (4) determine whether a correlation exists between defect size and treatment outcome. Study Design: Systematic review; Level of evidence, 4. Methods: PubMed, Ovid, and Cochrane databases were searched for clinical studies measuring glenoid defect size or location. We excluded studies with defect size requirements or pathology other than anterior instability and studies that included patients with known prior surgery. Our search produced 83 studies; 38 studies provided numeric measurements for glenoid defect size and 2 for defect location. Results: From 1981 to 2000, a total of 5.6% (1 of 18) of the studies reported numeric measurements for glenoid defect size; from 2001 to 2014, the rate of reporting glenoid defects increased to 58.7% (37 of 63). Fourteen studies (n = 1363 shoulders) reported defect size ranges for percentage loss of glenoid width, and 9 studies (n = 570 shoulders) reported defect size ranges for percentage loss of glenoid surface area. According to 2 studies, the mean glenoid defect orientation was pointing toward the 3:01 and 3:20 positions on the glenoid clock face. Conclusion: Since 2001, the rate of reporting numeric measurements for glenoid defect size was only 58.7%. Among studies reporting the percentage loss of glenoid width, 23.6% of shoulders had a defect between 10% and 25%, and among studies reporting the percentage loss of glenoid surface area, 44.7% of shoulders had a defect between 5% and 20%. There is significant variability in the way glenoid bone loss is measured, calculated

Three-dimensional echocardiographic assessment of atrial septal defects

Directory of Open Access Journals (Sweden)

Charles German

2015-01-01

Full Text Available Echocardiography provides a useful tool in the diagnosis of many congenital heart diseases, including atrial septal defects, and aids in further delineating treatment options. Although two-dimensional echocardiography has been the standard of care in this regard, technological advancements have made three-dimensional echocardiography possible, and the images obtained in this new imaging modality are able to accurately portray the morphology, location, dimensions, and dynamic changes of defects and many other heart structures during the cardiac cycle.

Study on on-machine defects measuring system on high power laser optical elements

Science.gov (United States)

Luo, Chi; Shi, Feng; Lin, Zhifan; Zhang, Tong; Wang, Guilin

2017-10-01

The influence of surface defects on high power laser optical elements will cause some harm to the performances of imaging system, including the energy consumption and the damage of film layer. To further increase surface defects on high power laser optical element, on-machine defects measuring system was investigated. Firstly, the selection and design are completed by the working condition analysis of the on-machine defects detection system. By designing on processing algorithms to realize the classification recognition and evaluation of surface defects. The calibration experiment of the scratch was done by using the self-made standard alignment plate. Finally, the detection and evaluation of surface defects of large diameter semi-cylindrical silicon mirror are realized. The calibration results show that the size deviation is less than 4% that meet the precision requirement of the detection of the defects. Through the detection of images the on-machine defects detection system can realize the accurate identification of surface defects.

Deep-level defects in semiconductors: studies by magnetic resonance

International Nuclear Information System (INIS)

Ammerlaan, C.A.J.

1983-01-01

This work is divided into two parts. In the first one, the following topics are discussed: paramagnetic centers in semiconductors, principles of magnetic resonance, spin-Hamiltonian, g-tensor, hyperfine interaction, magnetic resonance spectrometer. In the second part it is dicussed defects studied by magnetic resonance including vacancy and divacancy in silicon, iron in silicon, nitrogen in diamond and antisite defects in III-V compounds. (A.C.A.S.) [pt

Point defects in solids

International Nuclear Information System (INIS)

Anon.

1978-01-01

The principal properties of point defects are studied: thermodynamics, electronic structure, interactions with etended defects, production by irradiation. Some measuring methods are presented: atomic diffusion, spectroscopic methods, diffuse scattering of neutron and X rays, positron annihilation, molecular dynamics. Then points defects in various materials are investigated: ionic crystals, oxides, semiconductor materials, metals, intermetallic compounds, carbides, nitrides [fr

Defect detection using transient thermography

International Nuclear Information System (INIS)

Mohd Zaki Umar; Ibrahim Ahmad; Ab Razak Hamzah; Wan Saffiey Wan Abdullah

2008-08-01

An experimental research had been carried out to study the potential of transient thermography in detecting sub-surface defect of non-metal material. In this research, eight pieces of bakelite material were used as samples. Each samples had a sub-surface defect in the circular shape with different diameters and depths. Experiment was conducted using one-sided Pulsed Thermal technique. Heating of samples were done using 30 kWatt adjustable quartz lamp while infra red (IR) images of samples were recorded using THV 550 IR camera. These IR images were then analysed with ThermofitTMPro software to obtain the Maximum Absolute Differential Temperature Signal value, ΔΤ m ax and the time of its appearance, τ m ax (ΔΤ). Result showed that all defects were able to be detected even for the smallest and deepest defect (diameter = 5 mm and depth = 4 mm). However the highest value of Differential Temperature Signal (ΔΤ m ax), were obtained at defect with the largest diameter, 20 mm and at the shallowest depth, 1 mm. As a conclusion, the sensitivity of the pulsed thermography technique to detect sub-surface defects of bakelite material is proportionately related with the size of defect diameter if the defects are at the same depth. On the contrary, the sensitivity of the pulsed thermography technique inversely related with the depth of defect if the defects have similar diameter size. (Author)

Associations Between Disinfection By-Product Exposures and Craniofacial Birth Defects.

Science.gov (United States)

Kaufman, John A; Wright, J Michael; Evans, Amanda; Rivera-Núñez, Zorimar; Meyer, Amy; Narotsky, Michael G

2018-02-01

The aim of this study was to examine associations between craniofacial birth defects (CFDs) and disinfection by-product (DBP) exposures, including the sum of four trihalomethanes (THM4) and five haloacetic acids (HAA5) (ie, DBP9). We calculated first trimester adjusted odds ratios (aORs) for different DBPs in a matched case-control study of 366 CFD cases in Massachusetts towns with complete 1999 to 2004 THM and HAA data. We detected elevated aORs for cleft palate with DBP9 (highest quintile aOR = 3.52; 95% CI: 1.07, 11.60), HAA5, trichloroacetic acid (TCAA), and dichloroacetic acid. We detected elevated aORs for eye defects with TCAA and chloroform. This is the first epidemiological study of DBPs to examine eye and ear defects, as well as HAAs and CFDs. The associations for cleft palate and eye defects highlight the importance of examining specific defects and DBPs beyond THM4.

Optical coherence tomography use in the diagnosis of enamel defects

Science.gov (United States)

Al-Azri, Khalifa; Melita, Lucia N.; Strange, Adam P.; Festy, Frederic; Al-Jawad, Maisoon; Cook, Richard; Parekh, Susan; Bozec, Laurent

2016-03-01

Molar incisor hypomineralization (MIH) affects the permanent incisors and molars, whose undermineralized matrix is evidenced by lesions ranging from white to yellow/brown opacities to crumbling enamel lesions incapable of withstanding normal occlusal forces and function. Diagnosing the condition involves clinical and radiographic examination of these teeth, with known limitations in determining the depth extent of the enamel defects in particular. Optical coherence tomography (OCT) is an emerging hard and soft tissue imaging technique, which was investigated as a new potential diagnostic method in dentistry. A comparison between the diagnostic potential of the conventional methods and OCT was conducted. Compared to conventional imaging methods, OCT gave more information on the structure of the enamel defects as well as the depth extent of the defects into the enamel structure. Different types of enamel defects were compared, each type presenting a unique identifiable pattern when imaged using OCT. Additionally, advanced methods of OCT image analysis including backscattered light intensity profile analysis and enface reconstruction were performed. Both methods confirmed the potential of OCT in enamel defects diagnosis. In conclusion, OCT imaging enabled the identification of the type of enamel defect and the determination of the extent of the enamel defects in MIH with the advantage of being a radiation free diagnostic technique.

EUV actinic defect inspection and defect printability at the sub-32 nm half pitch

Energy Technology Data Exchange (ETDEWEB)

Huh, Sungmin; Kearney, Patrick; Wurm, Stefan; Goodwin, Frank; Han, Hakseung; Goldberg, Kenneth; Mochi, Iacopp; Gullikson, Eric M.

2009-08-01

Extreme ultraviolet (EUV) mask blanks with embedded phase defects were inspected with a reticle actinic inspection tool (AIT) and the Lasertec M7360. The Lasertec M7360, operated at SEMA TECH's Mask Blank Development Center (MBDC) in Albany, NY, has a sensitivity to multilayer defects down to 40-45 nm, which is not likely sufficient for mask blank development below the 32 nm half-pitch node. Phase defect printability was simulated to calculate the required defect sensitivity for a next generation blank inspection tool to support reticle development for the sub-32 nm half-pitch technology node. Defect mitigation technology is proposed to take advantage of mask blanks with some defects. This technology will reduce the cost of ownership of EUV mask blanks. This paper will also discuss the kind of infrastructure that will be required for the development and mass production stages.

Multiple-level defect species evaluation from average carrier decay

Science.gov (United States)

Debuf, Didier

2003-10-01

An expression for the average decay is determined by solving the the carrier continuity equations, which include terms for multiple defect recombination. This expression is the decay measured by techniques such as the contactless photoconductance decay method, which determines the average or volume integrated decay. Implicit in the above is the requirement for good surface passivation such that only bulk properties are observed. A proposed experimental configuration is given to achieve the intended goal of an assessment of the type of defect in an n-type Czochralski-grown silicon semiconductor with an unusually high relative lifetime. The high lifetime is explained in terms of a ground excited state multiple-level defect system. Also, minority carrier trapping is investigated.

Intrinsic defects in silicon carbide for spin-based quantum applications

International Nuclear Information System (INIS)

Vladimir Dyakonov

2014-01-01

We present a set of experiments demonstrating a high potential of atomic-scale defects in SiC for various spin-based applications, including quantum information processing and photonics. In particular, we show that defect spn qubits in SiC can be addressed, manipulated and selectively read out by means of the double radio-optical resonance. The situation reminds the one in the atomic spectroscopy, where the atoms have their individual extremely sharp optical and RF resonance fingerprints. We also generate inverse population in some intrinsic defects, resulting in stimulated microwave emission at RT. This is a crucial step towards implementation of highly-integrable solid-state masers and extraordinarily sensitive microwave detectors. As an application example, we incorporate intrinsic defects in LED structures and show that they can be electrically driven at room temperature. (author)

Accurate defect die placement and nuisance defect reduction for reticle die-to-die inspections

Science.gov (United States)

Wen, Vincent; Huang, L. R.; Lin, C. J.; Tseng, Y. N.; Huang, W. H.; Tuo, Laurent C.; Wylie, Mark; Chen, Ellison; Wang, Elvik; Glasser, Joshua; Kelkar, Amrish; Wu, David

2015-10-01

Die-to-die reticle inspections are among the simplest and most sensitive reticle inspections because of the use of an identical-design neighboring-die for the reference image. However, this inspection mode can have two key disadvantages: (1) The location of the defect is indeterminate because it is unclear to the inspector whether the test or reference image is defective; and (2) nuisance and false defects from mask manufacturing noise and tool optical variation can limit the usable sensitivity. The use of a new sequencing approach for a die-to-die inspection can resolve these issues without any additional scan time, without sacrifice in sensitivity requirement, and with a manageable increase in computation load. In this paper we explore another approach for die-to-die inspections using a new method of defect processing and sequencing. Utilizing die-to-die double arbitration during defect detection has been proven through extensive testing to generate accurate placement of the defect in the correct die to ensure efficient defect disposition at the AIMS step. The use of this method maintained the required inspection sensitivity for mask quality as verified with programmed-defectmask qualification and then further validated with production masks comparing the current inspection approach to the new method. Furthermore, this approach can significantly reduce the total number of defects that need to be reviewed by essentially eliminating the nuisance and false defects that can result from a die-to-die inspection. This "double-win" will significantly reduce the effort in classifying a die-to-die inspection result and will lead to improved cycle times.

Multiscale crystal defect dynamics: A coarse-grained lattice defect model based on crystal microstructure

Science.gov (United States)

Lyu, Dandan; Li, Shaofan

2017-10-01

Crystal defects have microstructure, and this microstructure should be related to the microstructure of the original crystal. Hence each type of crystals may have similar defects due to the same failure mechanism originated from the same microstructure, if they are under the same loading conditions. In this work, we propose a multiscale crystal defect dynamics (MCDD) model that models defects by considering its intrinsic microstructure derived from the microstructure or material genome of the original perfect crystal. The main novelties of present work are: (1) the discrete exterior calculus and algebraic topology theory are used to construct a scale-up (coarse-grained) dual lattice model for crystal defects, which may represent all possible defect modes inside a crystal; (2) a higher order Cauchy-Born rule (up to the fourth order) is adopted to construct atomistic-informed constitutive relations for various defect process zones, and (3) an hierarchical strain gradient theory based finite element formulation is developed to support an hierarchical multiscale cohesive (process) zone model for various defects in a unified formulation. The efficiency of MCDD computational algorithm allows us to simulate dynamic defect evolution at large scale while taking into account atomistic interaction. The MCDD model has been validated by comparing of the results of MCDD simulations with that of molecular dynamics (MD) in the cases of nanoindentation and uniaxial tension. Numerical simulations have shown that MCDD model can predict dislocation nucleation induced instability and inelastic deformation, and thus it may provide an alternative solution to study crystal plasticity.

Persistent renal cortical scintigram defects in children 2 years after urinary tract infection

International Nuclear Information System (INIS)

Ditchfield, Michael R.; Cook, David J.; Campo, John F. de; Grimwood, Keith; Powell, Harley R.; Gulati, Sanjeev; Sloane, Robert

2004-01-01

Background: Renal cortical scintigraphic studies challenge the role of vesicoureteric reflux in renal scar development, emphasizing instead the part played by acute pyelonephritis. Objective: To determine the prevalence of renal cortical defects in a child cohort 2 years after the child's first diagnosed urinary tract infection and to analyze the relationship of these defects with acute illness variables, primary vesicoureteric reflux and recurrent infections. Materials and methods: In a prospective cohort study, 193 children younger than 5 years with their first proven urinary tract infection underwent renal sonography, voiding cystourethrogram, and renal cortical scintigraphy within 15 days of diagnosis. Two years later, 150 of the 193 children, or 77.7%, had a further renal cortical scintigram, including 75, or 86.2%, of the 87 children who had acute scintigraphic defects. The relationship of cortical defects to age, gender, pre-treatment symptom duration, hospitalization, presence and grade of vesicoureteric reflux, and recurrent urinary tract infections was evaluated. Results: Overall, 20 of the 150 (13.3%; 95% confidence interval (CI) 8.3, 19.8) children had persistent defects 2 years after infection. This included 20 of 75 (26.7%; 95% CI 17.1, 38.1) with initially abnormal scintigrams. No new defects were detected. Although acute defects were more common in the young, those with persistent defects were older (median ages 16.4 vs. 6.8 months, P=0.004) than those with transient abnormalities. After adjustment for age, persistent defects were no longer associated with gender and were not predicted by acute illness variables, primary vesicoureteric reflux or recurrent infections. (orig.)

Surface defects and chiral algebras

Energy Technology Data Exchange (ETDEWEB)

Córdova, Clay [School of Natural Sciences, Institute for Advanced Study,1 Einstein Dr, Princeton, NJ 08540 (United States); Gaiotto, Davide [Perimeter Institute for Theoretical Physics,31 Caroline St N, Waterloo, ON N2L 2Y5 (Canada); Shao, Shu-Heng [School of Natural Sciences, Institute for Advanced Study,1 Einstein Dr, Princeton, NJ 08540 (United States)

2017-05-26

We investigate superconformal surface defects in four-dimensional N=2 superconformal theories. Each such defect gives rise to a module of the associated chiral algebra and the surface defect Schur index is the character of this module. Various natural chiral algebra operations such as Drinfeld-Sokolov reduction and spectral flow can be interpreted as constructions involving four-dimensional surface defects. We compute the index of these defects in the free hypermultiplet theory and Argyres-Douglas theories, using both infrared techniques involving BPS states, as well as renormalization group flows onto Higgs branches. In each case we find perfect agreement with the predicted characters.

Sensitivity of three tree ferns during their first phase of life to the variation of solar radiation and water availability in a Mexican cloud forest.

Science.gov (United States)

Riaño, Karolina; Briones, Oscar

2015-09-01

Regeneration niche differentiation promotes species coexistence and diversity; however, the ecological implications for the initial life phases of the majority of pteridophytes are unknown. We analyzed the sensitivity of gametophytes and juvenile sporophytes of the tree ferns Alsophila firma, Cyathea divergens, and Lophosoria quadripinnata to variation in light and water availability. We evaluated gametophyte desiccation tolerance using saturated salt solutions and gametophyte solar radiation tolerance by direct exposure. We also transplanted juvenile sporophytes in environments with 7% and 23% canopy openness and two watering levels. The response of photosynthetic efficiency and water content suggest that the gametophytes of the three species require high relative humidity, tolerate direct solar radiation for up to 30 min and that the response is not species-dependent. Sporophyte size and gas exchange were greater in the more open site, but decreased watering had a lesser effect on these variables in the more closed site. Relative growth rate correlated with the net assimilation rate and leaf weight ratio. Juvenile sporophytes of A. firma were more shade tolerant, while those of C. divergens and L. quadripinnata acclimatized to both environments. Specialization to humid habitats in the tree fern gametophyte restricts the species to humid forests, while differences in the plasticity of the sporophyte facilitate coexistence of the species. © 2015 Botanical Society of America.

Laterality defects in the national birth defects prevention study 1998-2007 birth prevalence and descriptive epidemiology

Science.gov (United States)

Little is known epidemiologically about laterality defects. Using data from the National Birth Defects Prevention Study (NBDPS), a large multi-site case-control study of birth defects, we analyzed prevalence and selected characteristics in children born with laterality defects born from 1998 to 2007...

Pupillary anomaly masquerading as a glaucomatous visual field defect: a case report

Directory of Open Access Journals (Sweden)

Tey Adrian

2004-06-01

Full Text Available Abstract Background Patients are often referred to ophthalmologists with focal visual field defects on routine testing, possibly related to a potential diagnosis of glaucoma. However, examination of the individual patient's ocular characteristics as well as facial characteristics may often reveal a cause of the visual field defect. Case presentation We describe a patient who was found to have a superior visual field defect on routine testing by the optician. Repeat perimetry with pharmacological dilatation of the pupil revealed that the cause of the field defect was related to an eccentric inferiorly displaced pupil, secondary to trauma some years previously. Discussion Individual patient characteristics, including both ocular, as well as facial, need to be considered, when interpreting any visual field defect.

Defect-induced ferromagnetism in semiconductors: A controllable approach by particle irradiation

International Nuclear Information System (INIS)

Zhou, Shengqiang

2014-01-01

Making semiconductors ferromagnetic has been a long dream. One approach is to dope semiconductors with transition metals (TM). TM ions act as local moments and they couple with free carriers to develop collective magnetism. However, there are no fundamental reasons against the possibility of local moment formation from localized sp states. Recently, ferromagnetism was observed in nonmagnetically doped, but defective semiconductors or insulators including ZnO and TiO 2 . This kind of observation challenges the conventional understanding of ferromagnetism. Often the defect-induced ferromagnetism has been observed in samples prepared under non-optimized condition, i.e. by accident or by mistake. Therefore, in this field theory goes much ahead of experimental investigation. To understand the mechanism of the defect-induced ferromagnetism, one needs a better controlled method to create defects in the crystalline materials. As a nonequilibrium and reproducible approach of inducing defects, ion irradiation provides such a possibility. Energetic ions displace atoms from their equilibrium lattice sites, thus creating mainly vacancies, interstitials or antisites. The amount and the distribution of defects can be controlled by the ion fluence and energy. By ion irradiation, we have generated defect-induced ferromagnetism in ZnO, TiO 2 and SiC. In this short review, we also summarize some results by other groups using energetic ions to introduce defects, and thereby magnetism in various materials. Ion irradiation combined with proper characterizations of defects could allow us to clarify the local magnetic moments and the coupling mechanism in defective semiconductors. Otherwise we may have to build a new paradigm to understand the defect-induced ferromagnetism

Enamel Defects of Human Primary Dentition as Virtual Memory of Early Developmental Events

Directory of Open Access Journals (Sweden)

Naser Asl Aminabadi

2009-12-01

Full Text Available Background and aims. The objectives of the present study were to investigate the prevalence and the position of enamel defects of primary teeth and hence to estimate the approximate time of an insult. Material and methods. 121 children aged 3 to 5 years were included in the study. The Modified Developmental Defects of Enamel Index was used to diagnose and classify the defects. The defects were categorized as hypoplasia, hypocalcification or a combination of them. Each tooth was investigated for occlusal/incisal, middle, cervical, incisomiddle, cervicomiddle and complete crown defects. Results. 55.37% of the children were affected by enamel defects, 23.96% being categorized as hypocalcification and 22.31% as hypoplasia. The enamel defects were more abundant in maxillary primary incisors and mandibular primary canines. Minimum involvement was seen in maxillary primary second molars and mandibular primary lateral incisors. The prevalence of cervical defects in maxillary primary incisors was significantly more than the middle or incisal defects (P < 0.05. The prevalence of incisal defects in mandibular primary incisors was significantly more than the middle or cervical defects (P < 0.05. Conclusions. The results revealed a considerable number of enamel defects which are multiple, symmetric and chronologically accordant with the estimated neonatal line in primary teeth of healthy children.

Fundamental investigation of point defect interactions in FE-CR alloys

International Nuclear Information System (INIS)

Wirth, B.D.; Lee, H.J.; Wong, K.

2008-01-01

Full text of publication follows. Fe-Cr alloys are a leading candidate material for structural applications in Generation TV and fusion reactors, and there is a relatively large database on their irradiation performance. However, complete understanding of the response of Fe-Cr alloys to intermediate-to-high temperature irradiation, including the radiation induced segregation of Cr, requires knowledge of point defect and point defect cluster interactions with Cr solute atoms and impurities. We present results from a hierarchical multi-scale modelling approach of defect cluster behaviour in Fe-Cr alloys. The modelling includes ab initio electronic structure calculations performed using the VASP code with projector-augmented electron wave functions using PBE pseudo-potentials and a collinear treatment of magnetic spins, molecular dynamics using semi-empirical Finnic-Sinclair type potentials, and kinetic Monte Carlo simulations of coupled defect and Cr transport responsible for microstructural evolution. The modelling results are compared to experimental observations in both binary Fe-Cr and more complex ferritic-martensitic alloys, and provide a basis for understanding a dislocation loop evolution and the observations of Cr enrichment and depletion at grain boundaries in various irradiation experiments. (authors)

Defect phase diagram for doping of Ga2O3

Science.gov (United States)

Lany, Stephan

2018-04-01

For the case of n-type doping of β-Ga2O3 by group 14 dopants (C, Si, Ge, Sn), a defect phase diagram is constructed from defect equilibria calculated over a range of temperatures (T), O partial pressures (pO2), and dopant concentrations. The underlying defect levels and formation energies are determined from first-principles supercell calculations with GW bandgap corrections. Only Si is found to be a truly shallow donor, C is a deep DX-like (lattice relaxed donor) center, and Ge and Sn have defect levels close to the conduction band minimum. The thermodynamic modeling includes the effect of association of dopant-defect pairs and complexes, which causes the net doping to decline when exceeding a certain optimal dopant concentration. The optimal doping levels are surprisingly low, between about 0.01% and 1% of cation substitution, depending on the (T, pO2) conditions. Considering further the stability constraints due to sublimation of molecular Ga2O, specific predictions of optimized pO2 and Si dopant concentrations are given. The incomplete passivation of dopant-defect complexes in β-Ga2O3 suggests a design rule for metastable doping above the solubility limit.

Observation of defects evolution in electronic materials

Science.gov (United States)

Jang, Jung Hun

Advanced characterization techniques have been used to obtain a better understanding of the microstructure of electronic materials. The structural evolution, especially defects, has been investigated during the film growth and post-growth processes. Obtaining the relation between the defect evolution and growth/post-growth parameters is very important to obtain highly crystalline films. In this work, the growth and post-growth related defects in GaN, ZnO, strained-Si/SiGe films have been studied using several advanced characterization techniques. First of all, the growth of related defects in GaN and p-type ZnO films have been studied. The effect of growth parameters, such as growth temperature, gas flow rate, dopants used during the deposition, on the crystalline quality of the GaN and ZnO layers was investigated by high resolution X-ray diffraction (HRXRD) and transmission electron microscopy (TEM). In GaN films, it was found that the edge and mixed type threading dislocations were the dominant defects so that the only relevant figure of merit (FOM) for the crystalline quality should be the FWHM value of o-RC of the surface perpendicular plane which could be determined by a grazing incidence x-ray diffraction (GIXD) technique as shown in this work. The understanding of the relationship between the defect evolution and growth parameters allowed for the growth of high crystalline GaN films. For ZnO films, it was found that the degree of texture and crystalline quality of P-doped ZnO films decreased with increasing the phosphorus atomic percent. In addition, the result from the x-ray diffraction line profile analysis showed that the 0.5 at % P-doped ZnO film showed much higher microstrain than the 1.0 at % P-doped ZnO film, which indicated that the phosphorus atoms were segregated with increasing P atomic percentage. Finally, post-growth related defects in strained-Si/SiGe films were investigated. Postgrowth processes used in this work included high temperature N2

Test and Diagnosis for Small-Delay Defects

CERN Document Server

Tehranipoor, Mohammad; Chakrabarty, Krishnendu

2012-01-01

This book introduces new techniques for detecting and diagnosing small-delay defects (SDD) in integrated circuits. Although this sort of timing defect is commonly found in integrated circuits manufactured with nanometer technology, this will be the first book to introduce effective and scalable methodologies for screening and diagnosing small-delay defects, including important parameters such as process variations, crosstalk, and power supply noise. This book presents new techniques and methodologies to improve overall SDD detection with very small pattern sets. These methods can result in pattern counts as low as a traditional 1-detect pattern set and long path sensitization and SDD detection similar to or even better than n-detect or timing-aware pattern sets. The important design parameters and pattern-induced noises such as process variations,power supply noise (PSN) and crosstalk are taken into account in the methodologies presented. A diagnostic flow is also presented to identify whether the failure is ...

Stability and Electronic Properties of Hydrogenated Zigzag Carbon Nanotube Focused on Stone-Wales Defect

International Nuclear Information System (INIS)

Pan Li-Jun; Zhang Jie; Chen Wei-Guang; Tang Ya-Nan

2015-01-01

We present a first-principles study of the chemisorption of hydrogen on a Stone-Wales (SW) defective carbon nanotube (10,0). The investigated configurations include four configurations covering single defects and double defects. One hydrogen dimer adsorption is energetically favored on bonds shared by carbon heptagon-heptagon for configurations with the defect parallel to the tube axis compared with the carbon pentagon-hexagon sites for ones with a slanted defect. This different behavior is also demonstrated for hydrogen dimer chain adsorption, the favored site for the former ones is through the defect, which is the nearest neighbor site to defect for the latter ones. It is found that the energy band gaps of hydrogenated configurations may be enlarged or decreased by altering the adsorption site or defect position. The semiconductor-to-metal transition may occur for configurations with the defect or defects parallel to the tube axis due to low electronic localization. Our results highlight the interest of the interaction of multi-factor system by providing a detailed bond and position picture of a hydrogenated defective carbon nanotube (10,0). (paper)

Defects at oxide surfaces

CERN Document Server

Thornton, Geoff

2015-01-01

This book presents the basics and characterization of defects at oxide surfaces. It provides a state-of-the-art review of the field, containing information to the various types of surface defects, describes analytical methods to study defects, their chemical activity and the catalytic reactivity of oxides. Numerical simulations of defective structures complete the picture developed. Defects on planar surfaces form the focus of much of the book, although the investigation of powder samples also form an important part. The experimental study of planar surfaces opens the possibility of applying the large armoury of techniques that have been developed over the last half-century to study surfaces in ultra-high vacuum. This enables the acquisition of atomic level data under well-controlled conditions, providing a stringent test of theoretical methods. The latter can then be more reliably applied to systems such as nanoparticles for which accurate methods of characterization of structure and electronic properties ha...

Scattering of electrons in copper by a Frenkel pair defect

Energy Technology Data Exchange (ETDEWEB)

Lodder, A.; Rijsdijk, G.A.; Bukman, D.J.; Baratta, A.J.; Molenaar, J.

1988-06-01

The Korringa-Kohn-Rostoker (KKR) Green function extended-defect formalism, used to describe the scattering of Bloch electrons in a dilute alloy, is generalised to include an asymmetric defect centred on a lattice site. The revised theory is then used to investigate conduction electron scattering from Frenkel pairs in Cu. Such defects consist of two self-interstitial atoms centred on a vacant lattice site forming a dumb-bell oriented along the <100> axis. The generalised formalism allows one to calculate the cluster t matrix T for the Frenkel pair cluster including the surrounding displaced nearest neighbours. It was found that the interstitials at the vacant lattice site could still be treated within the muffin-tin potential as a central scatterer characterised by a t matrix which is non-diagonal in the angular momentum. Electron scattering rates and Dingle temperatures are calculated and discussed in view of preliminary experimental results.

Scattering of electrons in copper by a Frenkel pair defect

International Nuclear Information System (INIS)

Lodder, A.; Rijsdijk, G.A.; Bukman, D.J.; Baratta, A.J.; Molenaar, J.

1988-01-01

The Korringa-Kohn-Rostoker (KKR) Green function extended-defect formalism, used to describe the scattering of Bloch electrons in a dilute alloy, is generalised to include an asymmetric defect centred on a lattice site. The revised theory is then used to investigate conduction electron scattering from Frenkel pairs in Cu. Such defects consist of two self-interstitial atoms centred on a vacant lattice site forming a dumb-bell oriented along the axis. The generalised formalism allows one to calculate the cluster t matrix T for the Frenkel pair cluster including the surrounding displaced nearest neighbours. It was found that the interstitials at the vacant lattice site could still be treated within the muffin-tin potential as a central scatterer characterised by a t matrix which is non-diagonal in the angular momentum. Electron scattering rates and Dingle temperatures are calculated and discussed in view of preliminary experimental results. (author)

48 CFR 1615.407-1 - Rate reduction for defective pricing or defective cost or pricing data.

Science.gov (United States)

2010-10-01

... defective pricing or defective cost or pricing data. 1615.407-1 Section 1615.407-1 Federal Acquisition... CONTRACTING METHODS AND CONTRACT TYPES CONTRACTING BY NEGOTIATION Contract Pricing 1615.407-1 Rate reduction for defective pricing or defective cost or pricing data. The clause set forth in section 1652.215-70...

48 CFR 1652.215-70 - Rate Reduction for Defective Pricing or Defective Cost or Pricing Data.

Science.gov (United States)

2010-10-01

... Defective Pricing or Defective Cost or Pricing Data. 1652.215-70 Section 1652.215-70 Federal Acquisition... CLAUSES AND FORMS CONTRACT CLAUSES Texts of FEHBP Clauses 1652.215-70 Rate Reduction for Defective Pricing or Defective Cost or Pricing Data. As prescribed in 1615.407-1, the following clause shall be...

Point defects in platinum

International Nuclear Information System (INIS)

Piercy, G.R.

1960-01-01

An investigation was made of the mobility and types of point defect introduced in platinum by deformation in liquid nitrogen, quenching into water from 1600 o C, or reactor irradiation at 50 o C. In all cases the activation energy for motion of the defect was determined from measurements of electrical resistivity. Measurements of density, hardness, and x-ray line broadening were also made there applicable. These experiments indicated that the principal defects remaining in platinum after irradiation were single vacant lattice sites and after quenching were pairs of vacant lattice sites. Those present after deformation In liquid nitrogen were single vacant lattice sites and another type of defect, perhaps interstitial atoms. (author)

Birth defects and genetic disorders among Arab Americans--Michigan, 1992-2003.

Science.gov (United States)

Yanni, Emad A; Copeland, Glenn; Olney, Richard S

2010-06-01

Birth defects and genetic disorders are leading causes of infant morbidity and mortality in many countries. Population-based data on birth defects among Arab-American children have not been documented previously. Michigan has the second largest Arab-American community in the United States after California. Using data from the Michigan Birth Defects Registry (MBDR), which includes information on parents' country of birth and ancestry, birth prevalences were estimated in offspring of Michigan women of Arab ancestry for 21 major categories of birth defects and 12 congenital endocrine, metabolic, and hereditary disorders. Compared with other non-Hispanic white children in Michigan, Arab-American children had similar or lower birth prevalences of the selected types of structural birth defects, with higher rates of certain hereditary blood disorders and three categories of metabolic disorders. These estimates are important for planning preconception and antenatal health care, genetic counseling, and clinical care for Arab Americans.

Seed defective reduction in automotive Electro-Deposition Coating Process of truck cabin

Science.gov (United States)

Sonthilug, Aekkalag; Chutima, Parames

2018-02-01

The case study company is one of players in Thailand’s Automotive Industry who manufacturing truck and bus for both domestic and international market. This research focuses on a product quality problem about seed defects occurred in the Electro-Deposition Coating Process of truck cabin. The 5-phase of Six Sigma methodology including D-Define, M-Measure, A-Analyze, I-Improve, and C-Control is applied to this research to identify root causes of problem for setting new parameters of each significant factor. After the improvement, seed defects in this process is reduced from 9,178 defects per unit to 876 defects per unit (90% improvement)

On the influence of extrinsic point defects on irradiation-induced point-defect distributions in silicon

International Nuclear Information System (INIS)

Vanhellemont, J.; Romano-Rodriguez, A.

1994-01-01

A semi-quantitative model describing the influence of interfaces and stress fields on {113}-defect generation in silicon during 1-MeV electron irradiation, is further developed to take into account also the role of extrinsic point defects. It is shown that the observed distribution of {113}-defects in high-flux electron-irradiated silicon and its dependence on irradiation temperature and dopant concentration can be understood by taking into account not only the influence of the surfaces and interfaces as sinks for intrinsic point defects but also the thermal stability of the bulk sinks for intrinsic point defects. In heavily doped silicon the bulk sinks are related with pairing reactions of the dopant atoms with the generated intrinsic point defects or related with enhanced recombination of vacancies and self-interstitials at extrinsic point defects. The obtained theoretical results are correlated with published experimental data on boron-and phosphorus-doped silicon and are illustrated with observations obtained by irradiating cross-section transmission electron microscopy samples of wafer with highly doped surface layers. (orig.)

Congenital heart defects in children with oral clefts

Directory of Open Access Journals (Sweden)

Nahvi H.

2007-09-01

Full Text Available   Background: Oral clefts are among the most common congenital anomalies. Infants with oral clefts often have other associated congenital defects, especially congenital heart defects. The reported incidences and the types of associated malformations and congenital heart defects vary between different studies. The purpose of this study was to assess the incidence of associated congenital heart defects in children with oral clefts. Methods: All infants with cleft lip and palate referred to the Children's Medical Center and Bahramy; the teaching Hospitals of the Tehran University of Medical Sciences from 1991 to 2005 were prospectively enrolled in this study group. All patients were examined and noted by an academic cleft team contain; a pediatrician and a pediatric surgeon, and received cardiac consultation and echocardiography by a pediatric cardiologist. non cardiac associated anomalies, still born and patients without echocardiography were excluded from the study.  Data including age, gender, exposure to contagions and high risk elements ,consanguinity and familial history of oral cleft, type of oral cleft, results of cardiac consultation and echocardiography and associated cardiac anomalies were cumulated and analyzed by SSPS version 13.5Results: Among the 284 infants with oral clefts, 162 were male (57% and 122 were female (43%. Seventy-nine patients (27.8% had cleft lip, 84 (29.5% had cleft palate and 121 (42.6% had both cleft lip and palate. Of all the patients, 21.1% had congenital heart defects. the most common type Of these congenital heart defects(28.3%  was atrial septal defect.Conclusions: For patients with cleft lip and palate, we recommend preoperative cardiac consultation, careful examination and routine echocardiography for associated cardiac anomalies, as well as appropriate management and prophylactic antibiotic therapy for those with associated congenital heart anomaly.

Influence of cover defects on the attenuation of radon with earthen covers

International Nuclear Information System (INIS)

Kalkwarf, D.R.; Mayer, D.W.

1983-11-01

Experimental and theoretical evaluations of radon flux through laboratory-scale defective soil columns are presented together with a survey of literature on the formation and prevention of defects in soil covers. This report focuses on air-filled, centimeter-scale defects that are most probable in earthen covers for attenuating radon emission from uranium-mill tailings. Examples include shirnkage and erosion cracks, erosion piping, animal burrows and air channels formed by the biodegradation of vegetation roots. Calculations based on mathematical models indicate that collections of defects which could increase the radon flux from an earthen cover by a factor of two would be easily detected by visual inspection. However, these models ignore air-turbulence in the defect and drying of the soil around the defect. Laboratory measurements showed that turbulent diffusion of radon occurred through defects as narrow as 0.3 cm when subjected to a transverse air velocity of 1 to 6 miles per hour at the surface. Both turbulence and more-rapid drying of soil can accelerate radon flux to the cover surface. Consequently, recommended methods to inhibit defect formation should be applied. 29 references, 3 figures, 5 tables

Classification of Atrial Septal Defect and Ventricular Septal Defect with Documented Hemodynamic Parameters via Cardiac Catheterization by Genetic Algorithms and Multi-Layered Artificial Neural Network

Directory of Open Access Journals (Sweden)

Mustafa Yıldız

2012-08-01

Full Text Available Introduction: We aimed to develop a classification method to discriminate ventricular septal defect and atrial septal defect by using severalhemodynamic parameters.Patients and Methods: Forty three patients (30 atrial septal defect, 13 ventricular septal defect; 26 female, 17 male with documentedhemodynamic parameters via cardiac catheterization are included to study. Such parameters as blood pressure values of different areas,gender, age and Qp/Qs ratios are used for classification. Parameters, we used in classification are determined by divergence analysismethod. Those parameters are; i pulmonary artery diastolic pressure, ii Qp/Qs ratio, iii right atrium pressure, iv age, v pulmonary arterysystolic pressure, vi left ventricular sistolic pressure, vii aorta mean pressure, viii left ventricular diastolic pressure, ix aorta diastolicpressure, x aorta systolic pressure. Those parameters detected from our study population, are uploaded to multi-layered artificial neuralnetwork and the network was trained by genetic algorithm.Results: Trained cluster consists of 14 factors (7 atrial septal defect and 7 ventricular septal defect. Overall success ratio is 79.2%, andwith a proper instruction of artificial neural network this ratio increases up to 89%.Conclusion: Parameters, belonging to artificial neural network, which are needed to be detected by the investigator in classical methods,can easily be detected with the help of genetic algorithms. During the instruction of artificial neural network by genetic algorithms, boththe topology of network and factors of network can be determined. During the test stage, elements, not included in instruction cluster, areassumed as in test cluster, and as a result of this study, we observed that multi-layered artificial neural network can be instructed properly,and neural network is a successful method for aimed classification.

Point defects in lines in single crystalline phosphorene: directional migration and tunable band gaps.

Science.gov (United States)

Li, Xiuling; Ma, Liang; Wang, Dayong; Zeng, Xiao Cheng; Wu, Xiaojun; Yang, Jinlong

2016-10-20

Extended line defects in two-dimensional (2D) materials can play an important role in modulating their electronic properties. During the experimental synthesis of 2D materials, line defects are commonly generated at grain boundaries between domains of different orientations. In this work, twelve types of line-defect structures in single crystalline phosphorene are examined by using first-principles calculations. These line defects are typically formed via migration and aggregation of intrinsic point defects, including the Stone-Wales (SW), single or double vacancy (SV or DV) defects. Our calculated results demonstrate that the migration of point defects in phosphorene is anisotropic, for instance, the lowest migration energy barriers are 1.39 (or 0.40) and 2.58 (or 0.49) eV for SW (or SV) defects in zigzag and armchair directions, respectively. The aggregation of point defects into lines is energetically favorable compared with the separated point defects in phosphorene. In particular, the axis of line defects in phosphorene is direction-selective, depending on the composed point defects. The presence of line defects effectively modulates the electronic properties of phosphorene, rendering the defect-containing phosphorene either metallic or semiconducting with a tunable band gap. Of particular interest is the fact that the SV-based line defect can behave as a metallic wire, suggesting a possibility to fabricate a circuit with subnanometer widths in the semiconducting phosphorene for nanoscale electronic application.

Congenital Heart Defects and CCHD

Science.gov (United States)

... and more. Stony Point, NY 10980 Close X Home > Complications & Loss > Birth defects & other health conditions > Congenital heart defects and ... in congenital heart defects. You have a family history of congenital heart ... syndrome or VCF. After birth Your baby may be tested for CCHD as ...

Neutron diffraction and lattice defects

International Nuclear Information System (INIS)

Hamaguchi, Yoshikazu

1974-01-01

Study on lattice defects by neutron diffraction technique is described. Wave length of neutron wave is longer than that of X-ray, and absorption cross-section is small. Number of defects observed by ESR is up to several defects, and the number studied with electron microscopes is more than 100. Information obtained by neutron diffraction concerns the number of defects between these two ranges. For practical analysis, several probable models are selected from the data of ESR or electron microscopes, and most probable one is determined by calculation. Then, defect concentration is obtained from scattering cross section. It is possible to measure elastic scattering exclusively by neutron diffraction. Minimum detectable concentration estimated is about 0.5% and 10 20 - 10 21 defects per unit volume. A chopper and a time of flight system are used as a measuring system. Cold neutrons are obtained from the neutron sources inserted into reactors. Examples of measurements by using similar equipments to PTNS-I system of Japan Atomic Energy Research Institute are presented. Interstitial concentration in the graphite irradiated by fast neutrons is shown. Defects in irradiated MgO were also investigated by measuring scattering cross section. Study of defects in Ge was made by measuring total cross section, and model analysis was performed in comparison with various models. (Kato, T.)

Maternal obesity and congenital heart defects: a population-based study123

Science.gov (United States)

Mills, James L; Troendle, James; Conley, Mary R; Carter, Tonia; Druschel, Charlotte M

2010-01-01

Background: Obesity affects almost one-third of pregnant women and causes many complications, including neural tube defects. It is not clear whether the risk of congenital heart defects, the most common malformations, is also increased. Objective: This study was conducted to determine whether obesity is associated with an increased risk of congenital heart defects. Design: A population-based, nested, case-control study was conducted in infants born with congenital heart defects and unaffected controls from the cohort of all births (n = 1,536,828) between 1993 and 2003 in New York State, excluding New York City. The type of congenital heart defect, maternal body mass index (BMI; in kg/m2), and other risk factors were obtained from the Congenital Malformations Registry and vital records. Mothers of 7392 congenital heart defect cases and 56,304 unaffected controls were studied. Results: All obese women (BMI ≥ 30) were significantly more likely than normal-weight women (BMI: 19–24.9) to have children with a congenital heart defect [odds ratio (OR): 1.15; 95% CI: 1.07, 1.23; P heart defects with increasing maternal obesity (P heart syndrome, aortic stenosis, pulmonic stenosis, and tetralogy of Fallot. Conclusions: Obese, but not overweight, women are at significantly increased risk of bearing children with a range of congenital heart defects, and the risk increases with increasing BMI. Weight reduction as a way to reduce risk should be investigated. PMID:20375192

Time course of transient cortical scintigraphic defects associated with acute pyelonephritis

Energy Technology Data Exchange (ETDEWEB)

Ditchfield, Michael R.; Summerville, Dianne; Cook, David J.; Campo, John F. de [Department of Radiology, Royal Children' s Hospital, Melbourne 3052 (Australia); Grimwood, Keith; Nolan, Terrance M. [Department of General Paediatrics, Royal Children' s Hospital, Melbourne (Australia); Department of Paediatrics, University of Melbourne, Melbourne (Australia); Powell, Harley R. [Department of Nephrology, Royal Children' s Hospital, Melbourne (Australia); Sloane, Robert [Department of General Paediatrics, Royal Children' s Hospital, Melbourne (Australia)

2002-12-01

Acute pyelonephritis is distinguished from renal scarring using repeat cortical scintigraphy. The defects of acute pyelonephritis resolve, while those of scars persist. To determine the duration of reversible cortical defects following acute pyelonephritis and the time interval required to differentiate infection from scars. Materials and methods. An observational prospective study of 193 children (386 kidneys) aged less than 5 years following their first proven urinary tract infection (UTI). Renal cortical scintigraphic defects were detected in 112 (29%) kidneys within 15 days of diagnosis. Of these, 95 underwent repeat renal cortical scans 2 years after the UTI, including 50 with additional scans performed within 2-6 months of infection. Of the 50 kidneys undergoing a second renal cortical scan within 2-6 months of the first UTI, 22 (44%) had persistent defects. A third scan was performed on 17 (77%) kidneys after 2 years, by which time defects had resolved in another 8 (47%) kidneys. The predictive value of defects detected within 2-6 months of UTI representing scars is 53% (95% CI 28, 77). Overall, nine (18%) kidneys with initial renal cortical abnormalities had permanent defects. In the 45 kidneys undergoing a second cortical scan more than 6 months after the UTI, 11 (24%) had persistent defects. None of the 95 kidneys undergoing serial scans developed new or larger defects. Renal scars may not be reliably diagnosed by cortical scintigraphy performed within 6 months of UTI because the inflammatory lesions may not have fully resolved. (orig.)

Time course of transient cortical scintigraphic defects associated with acute pyelonephritis

International Nuclear Information System (INIS)

Ditchfield, Michael R.; Summerville, Dianne; Cook, David J.; Campo, John F. de; Grimwood, Keith; Nolan, Terrance M.; Powell, Harley R.; Sloane, Robert

2002-01-01

Acute pyelonephritis is distinguished from renal scarring using repeat cortical scintigraphy. The defects of acute pyelonephritis resolve, while those of scars persist. To determine the duration of reversible cortical defects following acute pyelonephritis and the time interval required to differentiate infection from scars. Materials and methods. An observational prospective study of 193 children (386 kidneys) aged less than 5 years following their first proven urinary tract infection (UTI). Renal cortical scintigraphic defects were detected in 112 (29%) kidneys within 15 days of diagnosis. Of these, 95 underwent repeat renal cortical scans 2 years after the UTI, including 50 with additional scans performed within 2-6 months of infection. Of the 50 kidneys undergoing a second renal cortical scan within 2-6 months of the first UTI, 22 (44%) had persistent defects. A third scan was performed on 17 (77%) kidneys after 2 years, by which time defects had resolved in another 8 (47%) kidneys. The predictive value of defects detected within 2-6 months of UTI representing scars is 53% (95% CI 28, 77). Overall, nine (18%) kidneys with initial renal cortical abnormalities had permanent defects. In the 45 kidneys undergoing a second cortical scan more than 6 months after the UTI, 11 (24%) had persistent defects. None of the 95 kidneys undergoing serial scans developed new or larger defects. Renal scars may not be reliably diagnosed by cortical scintigraphy performed within 6 months of UTI because the inflammatory lesions may not have fully resolved. (orig.)

Diagnosis of atrial septal defect using magnetic resonance imaging

International Nuclear Information System (INIS)

Sakakibara, Makoto; Kobayashi, Shiro; Imai, Hitoshi; Watanabe, Shigeru; Masuda, Yoshiaki; Inagaki, Yoshiaki

1987-01-01

The capability of magnetic resonance imaging (MRI) to detect atrial septal defect (ASD) was evaluated in 28 ASD patients of diagnostic confirmation, including five with complicated anomaly. Findings of MRI obtained from 7 normal volunteers and 142 patients with acquired heart diseases were used as controls. Non-gated MRI, performed in three ASD patients, failed to reveal defect areas ; gated MRI, in the other 25 patients, depicted defects in the interatrial septum corresponding to findings of surgery and cardiac catheterizatioin, which allowed the site and size of ASD to be determined. Other findings of MRI included right atrial dilatation, right ventricular hypertrophy and dilatation, and pulmonary artery dilatation in majority of ASD patients. Complex anomalies associated with ADS were also clearly shown on MRI. The interatrial septum was shown on gated-MRI in 124 control subjects, 17 of whom had an extremely faint signal from the central portion of the interatrial septum. The results indicate that gated MRI is a valuable noninvasive method in the diagnosis of ASD and complicating anomalies. (Namekawa, K.)

Varying stiffness and load distributions in defective ball bearings: Analytical formulation and application to defect size estimation

Science.gov (United States)

Petersen, Dick; Howard, Carl; Prime, Zebb

2015-02-01

This paper presents an analytical formulation of the load distribution and varying effective stiffness of a ball bearing assembly with a raceway defect of varying size, subjected to static loading in the radial, axial and rotational degrees of freedom. The analytical formulation is used to study the effect of the size of the defect on the load distribution and varying stiffness of the bearing assembly. The study considers a square-shaped outer raceway defect centered in the load zone and the bearing is loaded in the radial and axial directions while the moment loads are zero. Analysis of the load distributions shows that as the defect size increases, defect-free raceway sections are subjected to increased static loading when one or more balls completely or partly destress when positioned in the defect zone. The stiffness variations that occur when balls pass through the defect zone are significantly larger and change more rapidly at the defect entrance and exit than the stiffness variations that occur for the defect-free bearing case. These larger, more rapid stiffness variations generate parametric excitations which produce the low frequency defect entrance and exit events typically observed in the vibration response of a bearing with a square-shaped raceway defect. Analysis of the stiffness variations further shows that as the defect size increases, the mean radial stiffness decreases in the loaded radial and axial directions and increases in the unloaded radial direction. The effects of such stiffness changes on the low frequency entrance and exit events in the vibration response are simulated with a multi-body nonlinear dynamic model. Previous work used the time difference between the low frequency entrance event and the high frequency exit event to estimate the size of the defect. However, these previous defect size estimation techniques cannot distinguish between defects that differ in size by an integer number of the ball angular spacing, and a third feature

Influence of neutrophil defects on Burkholderia cepacia complex pathogenesis

Directory of Open Access Journals (Sweden)

Laura A. Porter

2011-11-01

Full Text Available The Burkholderia cepacia complex (Bcc is a group of Gram-negative bacteria that are ubiquitous in the environment and have emerged as opportunistic pathogens in immunocompromised patients. The primary patient populations infected with Bcc include individuals with cystic fibrosis (CF, as well as those with chronic granulomatous disease (CGD. While Bcc infection in CF is better characterized than in CGD, these two genetic diseases are not obviously similar and it is currently unknown if there is any commonality in host immune defects that is responsible for the susceptibility to Bcc. CF is caused by mutations in the CF transmembrane conductance regulator, resulting in manifestations in various organ systems, however the major cause of morbidity and mortality is currently due to bacterial respiratory infections. CGD, on the other hand, is a genetic disorder that is caused by defects in phagocyte NADPH oxidase. Because of the defect in CGD, phagocytes in these patients are unable to produce reactive oxygen species, which results in increased susceptibility to bacterial and fungal infections. Despite this significant defect in microbial clearance, the spectrum of pathogens frequently implicated in infections in CGD is relatively narrow and includes some bacterial species that are considered almost pathognomonic for this disorder. Very little is known about the cause of the specific susceptibility to Bcc over other potential pathogens more prevalent in the environment, and a better understanding of specific mechanisms required for bacterial virulence has become a high priority. This review will summarize both the current knowledge and future directions related to Bcc virulence in immunocompromised individuals with a focus on the roles of bacterial factors and neutrophil defects in pathogenesis.

Computer simulation of defect cluster

Energy Technology Data Exchange (ETDEWEB)

Kuramoto, Eiichi [Kyushu Univ., Kasuga, Fukuoka (Japan). Research Inst. for Applied Mechanics

1996-04-01

In order to elucidate individual element process of various defects and defect clusters of used materials under irradiation environments, interatomic potential with reliability was investigated. And for comparison with experimental results, it is often required to adopt the temperature effect and to investigate in details mechanism of one dimensional motion of micro conversion loop and so forth using the molecular dynamic (MD) method. Furthermore, temperature effect is also supposed for stable structure of defects and defect clusters, and many problems relating to alloy element are also remained. And, simulation on photon life at the defects and defect clusters thought to be important under comparison with equipment can also be supposed an improvement of effectiveness due to relation to theses products. In this paper, some topics in such flow was extracted to explain them. In particular, future important problems will be potential preparation of alloy, structure, dynamic behavior and limited temperature of intralattice atomic cluster. (G.K.)

Congenital Heart Defects and Receipt of Special Education Services.

Science.gov (United States)

Riehle-Colarusso, Tiffany; Autry, Andrew; Razzaghi, Hilda; Boyle, Coleen A; Mahle, William T; Van Naarden Braun, Kim; Correa, Adolfo

2015-09-01

We investigated the prevalence of receipt of special education services among children with congenital heart defects (CHDs) compared with children without birth defects. Children born from 1982 to 2004 in metropolitan Atlanta with CHDs (n = 3744) were identified from a population-based birth defect surveillance program; children without birth defects (n = 860 715) were identified from birth certificates. Cohorts were linked to special education files for the 1992-2012 school years to identify special education services. Children with noncardiac defects or genetic syndromes were excluded; children with CHDs were classified by presence or absence of critical CHDs (ie, CHDs requiring intervention by age one year). We evaluated the prevalence of receipt of special education services and prevalence rate ratios using children without birth defects as a reference. Compared with children without birth defects, children with CHDs were 50% more likely to receive special education services overall (adjusted prevalence rate ratio [aPRR] = 1.5; 95% confidence interval [CI]: 1.4-1.7). Specifically, they had higher prevalence of several special education categories including: intellectual disability (aPRR = 3.8; 95% CI: 2.8-5.1), sensory impairment (aPRR = 3.0; 95% CI: 1.8-5.0), other health impairment (aPRR = 2.8; 95% CI: 2.2-3.5), significant developmental delay (aPRR = 1.9; 95% CI: 1.3-2.8), and specific learning disability (aPRR = 1.4; 95% CI: 1.1-1.7). For most special education services, the excess prevalence did not vary by presence of critical CHDs. Children with CHDs received special education services more often than children without birth defects. These findings highlight the need for special education services and the importance of developmental screening for all children with CHDs. Copyright © 2015 by the American Academy of Pediatrics.

Irradiated strut allografts for reconstructing tumour defects: how effective?

International Nuclear Information System (INIS)

Astrid Lobo Gajiwala; Manish Agarwal; Ajay Puri; Cynthia D Lima

2008-01-01

Full text: Allografts are biological options for reconstructing large bone defects. We report our experience with 87 irradiated (25 kGy of gamma radiation) strut allografts used in various defects following tumour surgery. Reconstruction in 35 full segment defects involved 22 full segment allografts used alone, 4 allograft prosthetic composites (APC) and 9 allografts combined with a vascularized fibula. Twelve partial segment defects were reconstructed with allograft struts (including 2 APC). Full segment allograft struts (mainly fibulae) were used in 40 contained post-curettage defects. The cases were studied for time to incorporation and complications. The follow-up ranged from 12 to 72 months. Of the 26 full segment defects where allograft alone or APC was used, 2 were lost to follow-up, 5 died before incorporation and 3 grafts were removed (2 infection and 1 local recurrence). Six united primarily at 2-4 years. Seven patients with non union were autografted at both junctions resulting in 6 unions. One patient had early plate breakage and refused further treatment. One allograft fractured after union after autografting. Two of 4 APC also united. In contrast, the 9 allograft-vascularized fibula combinations showed unambiguous incorporation between 5-9 months with only one junction requiring bone grafting. Of the 12 partial segment struts, barring one removed for infection, 11 have completely incorporated. Thirty one out of 40 struts placed within contained post curettage defects have incorporated (2 removed for infection and seven lost to follow-up). There were total 6 infections (7%) 4 of which occurred 1-2 years after surgery. Irradiated full segment struts alone incorporate poorly and are best used combined with a live fibula. Irradiated full and partial segment allografts used inside contained defects give consistently good results. Frozen grafts seem to incorporate faster and better than lyophilised grafts. (Author)

Use of porous silicon to minimize oxidation induced stacking fault defects in silicon

International Nuclear Information System (INIS)

Shieh, S.Y.; Evans, J.W.

1992-01-01

This paper presents methods for minimizing stacking fault defects, generated during oxidation of silicon, include damaging the back of the wafer or depositing poly-silicon on the back. In either case a highly defective structure is created and this is capable of gettering either self-interstitials or impurities which promote nucleation of stacking fault defects. A novel method of minimizing these defects is to form a patch of porous silicon on the back of the wafer by electrochemical etching. Annealing under inert gas prior to oxidation may then result in the necessary gettering. Experiments were carried out in which wafers were subjected to this treatment. Subsequent to oxidation, the wafers were etched to remove oxide and reveal defects. The regions of the wafer adjacent to the porous silicon patch were defect-free, whereas remote regions had defects. Deep level transient spectroscopy has been used to examine the gettering capability of porous silicon, and the paper discusses the mechanism by which the porous silicon getters

Norwegian Pitched Roof Defects

Directory of Open Access Journals (Sweden)

Lars Gullbrekken

2016-06-01

Full Text Available The building constructions investigated in this work are pitched wooden roofs with exterior vertical drainpipes and wooden load-bearing system. The aim of this research is to further investigate the building defects of pitched wooden roofs and obtain an overview of typical roof defects. The work involves an analysis of the building defect archive from the research institute SINTEF Building and Infrastructure. The findings from the SINTEF archive show that moisture is a dominant exposure factor, especially in roof constructions. In pitched wooden roofs, more than half of the defects are caused by deficiencies in design, materials, or workmanship, where these deficiencies allow moisture from precipitation or indoor moisture into the structure. Hence, it is important to increase the focus on robust and durable solutions to avoid defects both from exterior and interior moisture sources in pitched wooden roofs. Proper design of interior ventilation and vapour retarders seem to be the main ways to control entry from interior moisture sources into attic and roof spaces.

Modern approach to facial skin defects reconstruction

Directory of Open Access Journals (Sweden)

Mateusz Kister

2017-10-01

Full Text Available Reconstruction of a facial defect is usually a challenging endeavor. The article aims to describe different types of flaps that might be used to restore such deformities- including their characteristics, indications and guidelines that should be followed in the reconstructive procedures.

Congenital platelet function defects

Science.gov (United States)

... pool disorder; Glanzmann's thrombasthenia; Bernard-Soulier syndrome; Platelet function defects - congenital ... Congenital platelet function defects are bleeding disorders that cause reduced platelet function. Most of the time, people with these disorders have ...

Metallography of defects

International Nuclear Information System (INIS)

Borisova, E.A.; Bochvar, G.A.; Brun, M.Ya.

1980-01-01

Different types of defects of metallurgical, technological and exploitation origin in intermediate and final products of titanium alloys, are considered. The examples of metallic and nonmetallic inclusions, chemical homogeneity, different grains, bands, cracks, places of searing, porosity are given; methods of detecting the above defects are described. The methods of metallography, X-ray spectral analysis, measuring microhardness are used

Origins and consequences of congenital heart defects affecting the right ventricle.

Science.gov (United States)

Woudstra, Odilia I; Ahuja, Suchit; Bokma, Jouke P; Bouma, Berto J; Mulder, Barbara J M; Christoffels, Vincent M

2017-10-01

Congenital heart disease is a major health issue, accounting for a third of all congenital defects. Improved early surgical management has led to a growing population of adults with congenital heart disease, including patients with defects affecting the right ventricle, which are often classified as severe. Defects affecting the right ventricle often cause right ventricular volume or pressure overload and affected patients are at high risk for complications such as heart failure and sudden death. Recent insights into the developmental mechanisms and distinct developmental origins of the left ventricle, right ventricle, and the outflow tract have shed light on the common features and distinct problems arising in specific defects. Here, we provide a comprehensive overview of the current knowledge on the development into the normal and congenitally malformed right heart and the clinical consequences of several congenital heart defects affecting the right ventricle. Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2017. For permissions, please email: journals.permissions@oup.com.

Defect phase diagram for doping of Ga2O3

Directory of Open Access Journals (Sweden)

Stephan Lany

2018-04-01

Full Text Available For the case of n-type doping of β-Ga2O3 by group 14 dopants (C, Si, Ge, Sn, a defect phase diagram is constructed from defect equilibria calculated over a range of temperatures (T, O partial pressures (pO2, and dopant concentrations. The underlying defect levels and formation energies are determined from first-principles supercell calculations with GW bandgap corrections. Only Si is found to be a truly shallow donor, C is a deep DX-like (lattice relaxed donor center, and Ge and Sn have defect levels close to the conduction band minimum. The thermodynamic modeling includes the effect of association of dopant-defect pairs and complexes, which causes the net doping to decline when exceeding a certain optimal dopant concentration. The optimal doping levels are surprisingly low, between about 0.01% and 1% of cation substitution, depending on the (T, pO2 conditions. Considering further the stability constraints due to sublimation of molecular Ga2O, specific predictions of optimized pO2 and Si dopant concentrations are given. The incomplete passivation of dopant-defect complexes in β-Ga2O3 suggests a design rule for metastable doping above the solubility limit.

Extracting software static defect models using data mining

Directory of Open Access Journals (Sweden)

Ahmed H. Yousef

2015-03-01

Full Text Available Large software projects are subject to quality risks of having defective modules that will cause failures during the software execution. Several software repositories contain source code of large projects that are composed of many modules. These software repositories include data for the software metrics of these modules and the defective state of each module. In this paper, a data mining approach is used to show the attributes that predict the defective state of software modules. Software solution architecture is proposed to convert the extracted knowledge into data mining models that can be integrated with the current software project metrics and bugs data in order to enhance the prediction. The results show better prediction capabilities when all the algorithms are combined using weighted votes. When only one individual algorithm is used, Naïve Bayes algorithm has the best results, then the Neural Network and the Decision Trees algorithms.

Primary Ovarian Insufficiency: X chromosome defects and autoimmunity.

Science.gov (United States)

Persani, Luca; Rossetti, Raffaella; Cacciatore, Chiara; Bonomi, Marco

2009-08-01

Premature ovarian failure (POF) is a primary ovarian defect characterized by absent menarche or premature depletion of ovarian follicles before the age of 40 years. However, in several instances the distinction between definitive or intermittent POF may be difficult on clinical bases, therefore the more appropriate term Primary Ovarian Insufficiency (POI) has been recently proposed and will be used in this review. POI is a heterogeneous disorder affecting approximately 1% of women disappearance of menstrual cycles (secondary amenorrhea) associated with a defective folliculogenesis. POI is generally characterized by low levels of gonadal hormones (estrogens and inhibins) and high levels of gonadotropins (LH and FSH) (hypergonadotropic amenorrhea). Heterogeneity of POI is reflected by the variety of possible causes, including autoimmunity, toxics, drugs, as well as genetic defects. Several data indicate that POI has a strong genetic component. In this manuscript we discuss the X chromosome abnormalities that are associated with POI.

A proposed defect tracking model for classifying the inserted defect reports to enhance software quality control.

Science.gov (United States)

Sultan, Torky; Khedr, Ayman E; Sayed, Mostafa

2013-01-01

NONE DECLARED Defect tracking systems play an important role in the software development organizations as they can store historical information about defects. There are many research in defect tracking models and systems to enhance their capabilities to be more specifically tracking, and were adopted with new technology. Furthermore, there are different studies in classifying bugs in a step by step method to have clear perception and applicable method in detecting such bugs. This paper shows a new proposed defect tracking model for the purpose of classifying the inserted defects reports in a step by step method for more enhancement of the software quality.

Defect generation/passivation by low energy hydrogen implant for silicon solar cells

International Nuclear Information System (INIS)

Sopori, B.L.; Zhou, T.Q.; Rozgonyi, G.A.

1990-01-01

Low energy ion implant is shown to produce defects in silicon. These defects include surface damage, hydrogen agglomeration, formation of platelets with (111) habit plane and decoration of dislocations. Hydrogen also produces an inversion type of surface on boron doped silicon. These effects indicate that a preferred approach for passivation is to incorporate hydrogen from the back side of the cell. A backside H + implant technique is described. The results show that degree of passivation differs for various devices. A comparison of the defect structures of hydrogenated devices indicates that the structure and the distribution of defects in the bulk of the material plays a significant role in determining the degree of passivation

Implications of defect clusters formed in cascades on free defect generation and microstructural development

International Nuclear Information System (INIS)

Wiedersich, H.

1992-12-01

A large fraction of the defects produced by irradiation with energetic neutrons or heavy ions originates in cascades. Not only increased recombination of vacancy and interstitial defects but also significant clustering of like defects occur. Both processes reduce the number of point defects available for long range migration. Consequences of defect clustering in cascades will be discussed in a semi-quantitative form with the aid of calculations using a very simplified model: Quasi-steady-state distributions of immobile vacancy and/or interstitial clusters develop which, in turn, can become significant sinks for mobile defects, and, therefore reduce their lifetime. Although cluster sinks will cause segregation and, potentially, precipitation of second phases due to local changes of composition, the finite lifetime of clusters will not lead to lasting, local compositional changes. A transition from highly dense interstitial and vacancy cluster distributions to the void swelling regime occurs when the thermal evaporation of vacancies from small vacancy clusters becomes significant at higher temperatures. Unequal clustering of vacancies and interstitials leads to an imbalance of their fluxes of in the matrix and, hence, to unequal contributions to atom transport by interstitials and by vacancies even in the quasi-steady state approximation

Characterization of point defects in monolayer arsenene

Science.gov (United States)

Liang, Xiongyi; Ng, Siu-Pang; Ding, Ning; Wu, Chi-Man Lawrence

2018-06-01

Topological defects that are inevitably found in 2D materials can dramatically affect their properties. Using density functional theory (DFT) calculations and ab initio molecular dynamics (AIMD) method, the structural, thermodynamic, electronic and magnetic properties of six types of typical point defects in arsenene, i.e. the Stone-Wales defect, single and double vacancies and adatoms, were systemically studied. It was found that these defects were all more easily generated in arsenene with lower formation energies than those with graphene and silicene. Stone-Wales defects can be transformed from pristine arsenene by overcoming a barrier of 2.19 eV and single vacancy defects tend to coalesce into double vacancy defects by diffusion. However, a type of adatom defect does not exhibit kinetic stability at room temperature. In addition, SV defects and another type of adatom defect can remarkably affect the electronic and magnetic properties of arsenene, e.g. they can introduce localized states near the Fermi level, as well as a strongly local magnetic moment due to dangling bond and unpaired electron. Furthermore, the simulated scanning tunneling microscopy (STM) and Raman spectroscopy were computed and the types of point defects can be fully characterized by correlating the STM images and Raman spectra to the defective atomistic structures. The results provide significant insights to the effect of defects in arsenene for potential applications, as well as identifications of two helpful tools (STM and Raman spectroscopy) to distinguish the type of defects in arsenene for future experiments.

Management of Anterior Skull Base Defect Depending on Its Size and Location

Science.gov (United States)

Bernal-Sprekelsen, Manuel; Rioja, Elena; Enseñat, Joaquim; Enriquez, Karla; Viscovich, Liza; Agredo-Lemos, Freddy Enrique; Alobid, Isam

2014-01-01

Introduction. We present our experience in the reconstruction of these leaks depending on their size and location. Material and Methods. Fifty-four patients who underwent advanced skull base surgery (large defects, >20 mm) and 62 patients with CSF leaks of different origin (small, 2–10 mm, and midsize, 11–20 mm, defects) were included in the retrospective study. Large defects were reconstructed with a nasoseptal pedicled flap positioned on fat and fascia lata. In small and midsized leaks. Fascia lata in an underlay position was used for its reconstruction covered with mucoperiosteum of either the middle or the inferior turbinate. Results. The most frequent etiology for small and midsized defects was spontaneous (48.4%), followed by trauma (24.2%), iatrogenic (5%). The success rate after the first surgical reconstruction was 91% and 98% in large skull base defects and small/midsized, respectively. Rescue surgery achieved 100%. Conclusions. Endoscopic surgery for any type of skull base defect is the gold standard. The size of the defects does not seem to play a significant role in the success rate. Fascia lata and mucoperiosteum of the turbinate allow a two-layer reconstruction of small and midsized defects. For larger skull base defects, a combination of fat, fascia lata, and nasoseptal pedicled flaps provides a successful reconstruction. PMID:24895567

Beating Birth Defects

Centers for Disease Control (CDC) Podcasts

Each year in the U.S., one in 33 babies is affected by a major birth defect. Women can greatly improve their chances of giving birth to a healthy baby by avoiding some of the risk factors for birth defects before and during pregnancy. In this podcast, Dr. Stuart Shapira discusses ways to improve the chances of giving birth to a healthy baby.

Behavior of duplex stainless steel casting defects under mechanical loadings

International Nuclear Information System (INIS)

Jayet-Gendrot, S.; Gilles, P.

2000-01-01

Several components in the primary circuit of pressurized water reactors are made of cast duplex stainless steels. This material contains small casting defects, mainly shrinkage cavities, due to the manufacturing process. In safety analyses, the structural integrity of the components is studied under the most severe assumptions: presence of a large defect, accidental loadings and end-of-life material properties accounting for its thermal aging embrittlement at the service temperature. The casting defects are idealized as semi-circular surface cracks or notches that have envelope dimensions. In order to assess the real severity of the casting defects under mechanical loadings, an experimental program was carried out. It consisted of testing, under both cyclic and monotonic solicitations, three-point bend specimens containing either a natural defect (in the form of a localized cluster of cavities) or a machined notch having the dimensions of the cluster's envelope. The results show that shrinkage cavities are far less harmful than envelope notches thanks to the metal bridges between cavities. Under fatigue loadings, the generalized initiation of a cluster of cavities (defined when the cluster becomes a crack of the same global size) is reached for a number of cycles that is much higher than the one leading to the initiation of a notch. In the case of monotonic loadings, specimens with casting defects offer a very high resistance to ductile tearing. The tests are analyzed in order to develop a method that takes into account the behavior of casting defects in a more realistic fashion than by an envelope crack. Various approaches are investigated, including the search of equivalent defects or of criteria based on continuum mechanics concepts, and compared with literature data. This study shows the conservatism of current safety analyses in modeling casting defects by envelope semi-elliptical cracks and contributes to the development of alternative approaches. (orig.)

Toward Intelligent Software Defect Detection

Science.gov (United States)

Benson, Markland J.

2011-01-01

Source code level software defect detection has gone from state of the art to a software engineering best practice. Automated code analysis tools streamline many of the aspects of formal code inspections but have the drawback of being difficult to construct and either prone to false positives or severely limited in the set of defects that can be detected. Machine learning technology provides the promise of learning software defects by example, easing construction of detectors and broadening the range of defects that can be found. Pinpointing software defects with the same level of granularity as prominent source code analysis tools distinguishes this research from past efforts, which focused on analyzing software engineering metrics data with granularity limited to that of a particular function rather than a line of code.

"Palmar pivot flap" for resurfacing palmar lateral defects of the fingers.

Science.gov (United States)

Yam, Andrew; Peng, Yeong-Pin; Pho, Robert Wan-Heng

2008-12-01

Soft tissue defects on the lateral borders of the digits are difficult to reconstruct using local or local-regional flaps. We describe a "palmar pivot flap" to resurface an adjacent defect on the palmar-lateral aspect of the digit. The surgical technique is described. This flap is an axial pattern flap based on the subcutaneous transverse branches of the digital artery. The flap is pivoted up to 90 degrees on the neurovascular bundle in its base, into an adjacent defect. The flap can be raised from either the proximal or the middle phalangeal segments. It can cover defects sited from the level of the proximal interphalangeal joint up to the fingertip. The donor defect is limited to the same digit and is covered with a full-thickness skin graft. We have used this flap on 3 patients with defects at the middle phalangeal segment, the distal interphalangeal joint, and the fingertip. All healed primarily. One patient had a mild flexion contracture of the proximal interphalangeal joint, whereas the other 2 had no complications. The patients with distal interphalangeal joint and fingertip defects had excellent sensation in the flap (2-point discrimination of 5-6 mm). The palmar pivot flap is useful for resurfacing otherwise difficult defects on the lateral borders of the digits around and distal to the proximal interphalangeal joint, including those at the fingertip. It provides sensate, glabrous skin. The donor defect is on the same digit and is well hidden, producing an aesthetic and functional reconstruction.

Automatically high accurate and efficient photomask defects management solution for advanced lithography manufacture

Science.gov (United States)

Zhu, Jun; Chen, Lijun; Ma, Lantao; Li, Dejian; Jiang, Wei; Pan, Lihong; Shen, Huiting; Jia, Hongmin; Hsiang, Chingyun; Cheng, Guojie; Ling, Li; Chen, Shijie; Wang, Jun; Liao, Wenkui; Zhang, Gary

2014-04-01

Defect review is a time consuming job. Human error makes result inconsistent. The defects located on don't care area would not hurt the yield and no need to review them such as defects on dark area. However, critical area defects can impact yield dramatically and need more attention to review them such as defects on clear area. With decrease in integrated circuit dimensions, mask defects are always thousands detected during inspection even more. Traditional manual or simple classification approaches are unable to meet efficient and accuracy requirement. This paper focuses on automatic defect management and classification solution using image output of Lasertec inspection equipment and Anchor pattern centric image process technology. The number of mask defect found during an inspection is always in the range of thousands or even more. This system can handle large number defects with quick and accurate defect classification result. Our experiment includes Die to Die and Single Die modes. The classification accuracy can reach 87.4% and 93.3%. No critical or printable defects are missing in our test cases. The missing classification defects are 0.25% and 0.24% in Die to Die mode and Single Die mode. This kind of missing rate is encouraging and acceptable to apply on production line. The result can be output and reloaded back to inspection machine to have further review. This step helps users to validate some unsure defects with clear and magnification images when captured images can't provide enough information to make judgment. This system effectively reduces expensive inline defect review time. As a fully inline automated defect management solution, the system could be compatible with current inspection approach and integrated with optical simulation even scoring function and guide wafer level defect inspection.

Nanocarbon: Defect Architectures and Properties

Science.gov (United States)

Vuong, Amanda

The allotropes of carbon make its solid phases amongst the most diverse of any element. It can occur naturally as graphite and diamond, which have very different properties that make them suitable for a wide range of technological and commercial purposes. Recent developments in synthetic carbon include Highly Oriented Pyrolytic Graphite (HOPG) and nano-carbons, such as fullerenes, nanotubes and graphene. The main industrial application of bulk graphite is as an electrode material in steel production, but in purified nuclear graphite form, it is also used as a moderator in Advanced Gas-cooled Reactors across the United Kingdom. Both graphene and graphite are damaged over time when subjected to bombardment by electrons, neutrons or ions, and these have a wide range of effects on their physical and electrical properties, depending on the radiation flux and temperature. This research focuses on intrinsic defects in graphene and dimensional change in nuclear graphite. The method used here is computational chemistry, which complements physical experiments. Techniques used comprise of density functional theory (DFT) and molecular dynamics (MD), which are discussed in chapter 2 and chapter 3, respectively. The succeeding chapters describe the results of simulations performed to model defects in graphene and graphite. Chapter 4 presents the results of ab initio DFT calculations performed to investigate vacancy complexes that are formed in AA stacked bilayer graphene. In AB stacking, carbon atoms surrounding the lattice vacancies can form interlayer structures with sp2 bonding that are lower in energy compared to in-plane reconstructions. From the investigation of AA stacking, sp2 interlayer bonding of adjacent multivacancy defects in registry creates a type of stable sp2 bonded wormhole between the layers. Also, a new class of mezzanine structure characterised by sp3 interlayer bonding, resembling a prismatic vacancy loop has also been identified. The mezzanine, which is a

A fast button surface defects detection method based on convolutional neural network

Science.gov (United States)

Liu, Lizhe; Cao, Danhua; Wu, Songlin; Wu, Yubin; Wei, Taoran

2018-01-01

Considering the complexity of the button surface texture and the variety of buttons and defects, we propose a fast visual method for button surface defect detection, based on convolutional neural network (CNN). CNN has the ability to extract the essential features by training, avoiding designing complex feature operators adapted to different kinds of buttons, textures and defects. Firstly, we obtain the normalized button region and then use HOG-SVM method to identify the front and back side of the button. Finally, a convolutional neural network is developed to recognize the defects. Aiming at detecting the subtle defects, we propose a network structure with multiple feature channels input. To deal with the defects of different scales, we take a strategy of multi-scale image block detection. The experimental results show that our method is valid for a variety of buttons and able to recognize all kinds of defects that have occurred, including dent, crack, stain, hole, wrong paint and uneven. The detection rate exceeds 96%, which is much better than traditional methods based on SVM and methods based on template match. Our method can reach the speed of 5 fps on DSP based smart camera with 600 MHz frequency.

Atrioventricular canal defect and associated genetic disorders: new insights into polydactyly syndromes

Directory of Open Access Journals (Sweden)

M. Cristina Digilio

2011-07-01

Full Text Available Atrioventricular canal defect (AVCD is a common congenital heart defect (CHD, representing 7.4% of all cardiac malformations, considered secondary to an extracellular matrix anomaly. The AVCD is associated with extracardiac defects in about 75% of the cases. In this review we analyzed different syndromic AVCDs, in particular those associated with polydactyly disorders, which show remarkable genotype-phenotype correlations. Chromo - some imbalances more frequently associated with AVCD include Down syndrome, deletion 8p23 and deletion 3p25, while mendelian disorders include Noonan syndrome and related RASopathies, several polydactyly syndromes, CHARGE and 3C (cranio-cerebello-cardiac syndrome. The complete form of AVCD is prevalent in patients with chromosomal imbalances. Additional cardiac defects are found in patients affected by chromosomal imbalances different from Down syndrome. Left-sided obstructive lesions are prevalently found in patients with RASopathies. Patients with deletion 8p23 often display AVCD with tetralogy of Fallot or with pulmonary valve stenosis. Tetralogy of Fallot is the only additional cardiac defect found in patients with Down syndrome and AVCD. On the other hand, the association of AVCD and tetralogy of Fallot is also quite characteristic of CHARGE and 3C syndromes. Heterotaxia defects, including common atrium and anomalous pulmonary venous return, occur in patients with AVCD associated with polydactyly syndromes (Ellis-van Creveld, short rib polydactyly, oral-facial-digital, Bardet-Biedl, and Smith-Lemli-Opitz syndromes. The initial clinical evidence of anatomic similarities between AVCD and heterotaxia in polydactyly syndromes was corroborated and explained by experimental studies in transgenic mice. These investigations have suggested the involvement of the Sonic Hedgehog pathway in syndromes with postaxial polydactyly and heterotaxia, and ciliary dysfunction was detected as pathomechanism for these disorders

Embedded defects

International Nuclear Information System (INIS)

Barriola, M.; Vachaspati, T.; Bucher, M.

1994-01-01

We give a prescription for embedding classical solutions and, in particular, topological defects in field theories which are invariant under symmetry groups that are not necessarily simple. After providing examples of embedded defects in field theories based on simple groups, we consider the electroweak model and show that it contains the Z string and a one-parameter family of strings called the W(α) string. It is argued that although the members of this family are gauge equivalent when considered in isolation, each member becomes physically distinct when multistring configurations are considered. We then turn to the issue of stability of embedded defects and demonstrate the instability of a large class of such solutions in the absence of bound states or condensates. The Z string is shown to be unstable for all values of the Higgs boson mass when θ W =π/4. W strings are also shown to be unstable for a large range of parameters. Embedded monopoles suffer from the Brandt-Neri-Coleman instability. Finally, we connect the electroweak string solutions to the sphaleron

Study of residue type defect formation mechanism and the effect of advanced defect reduction (ADR) rinse process

Science.gov (United States)

Arima, Hiroshi; Yoshida, Yuichi; Yoshihara, Kosuke; Shibata, Tsuyoshi; Kushida, Yuki; Nakagawa, Hiroki; Nishimura, Yukio; Yamaguchi, Yoshikazu

2009-03-01

Residue type defect is one of yield detractors in lithography process. It is known that occurrence of the residue type defect is dependent on resist development process and the defect is reduced by optimized rinsing condition. However, the defect formation is affected by resist materials and substrate conditions. Therefore, it is necessary to optimize the development process condition by each mask level. Those optimization steps require a large amount of time and effort. The formation mechanism is investigated from viewpoint of both material and process. The defect formation is affected by resist material types, substrate condition and development process condition (D.I.W. rinse step). Optimized resist formulation and new rinse technology significantly reduce the residue type defect.

Precise design-based defect characterization and root cause analysis

Science.gov (United States)

Xie, Qian; Venkatachalam, Panneerselvam; Lee, Julie; Chen, Zhijin; Zafar, Khurram

2017-03-01

As semiconductor manufacturing continues its march towards more advanced technology nodes, it becomes increasingly important to identify and characterize design weak points, which is typically done using a combination of inline inspection data and the physical layout (or design). However, the employed methodologies have been somewhat imprecise, relying greatly on statistical techniques to signal excursions. For example, defect location error that is inherent to inspection tools prevents them from reporting the true locations of defects. Therefore, common operations such as background-based binning that are designed to identify frequently failing patterns cannot reliably identify specific weak patterns. They can only identify an approximate set of possible weak patterns, but within these sets there are many perfectly good patterns. Additionally, characterizing the failure rate of a known weak pattern based on inline inspection data also has a lot of fuzziness due to coordinate uncertainty. SEM (Scanning Electron Microscope) Review attempts to come to the rescue by capturing high resolution images of the regions surrounding the reported defect locations, but SEM images are reviewed by human operators and the weak patterns revealed in those images must be manually identified and classified. Compounding the problem is the fact that a single Review SEM image may contain multiple defective patterns and several of those patterns might not appear defective to the human eye. In this paper we describe a significantly improved methodology that brings advanced computer image processing and design-overlay techniques to better address the challenges posed by today's leading technology nodes. Specifically, new software techniques allow the computer to analyze Review SEM images in detail, to overlay those images with reference design to detect every defect that might be present in all regions of interest within the overlaid reference design (including several classes of defects

Strained interface defects in silicon nanocrystals

Energy Technology Data Exchange (ETDEWEB)

Lee, Benjamin G.; Stradins, Paul [National Center for Photovoltaics, National Renewable Energy Laboratory, Golden, CO (United States); Hiller, Daniel; Zacharias, Margit [IMTEK - Faculty of Engineering, Albert-Ludwigs-University Freiburg (Germany); Luo, Jun-Wei; Beard, Matthew C. [Chemical and Materials Science, National Renewable Energy Laboratory, Golden, CO (United States); Semonin, Octavi E. [Chemical and Materials Science, National Renewable Energy Laboratory, Golden, CO (United States); Department of Physics, University of Colorado, Boulder, CO (United States)

2012-08-07

The surface of silicon nanocrystals embedded in an oxide matrix can contain numerous interface defects. These defects strongly affect the nanocrystals' photoluminescence efficiency and optical absorption. Dangling-bond defects are nearly eliminated by H{sub 2} passivation, thus decreasing absorption below the quantum-confined bandgap and enhancing PL efficiency by an order of magnitude. However, there remain numerous other defects seen in absorption by photothermal deflection spectroscopy; these defects cause non-radiative recombination that limits the PL efficiency to <15%. Using atomistic pseudopotential simulations, we attribute these defects to two specific types of distorted bonds: Si-Si and bridging Si-O-Si bonds between two Si atoms at the nanocrystal surface. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Craniotomy Frontal Bone Defect

African Journals Online (AJOL)

2018-03-01

Mar 1, 2018 ... Defect reconstruction and fixation of the graft: The defect of ... where all loose fragments of fractured frontal bone was removed via the ... Mandible. • Ilium. • Allograft ... pediatric patients owing to skull growth. Thus, autologous ...

Who named the quantum defect?

International Nuclear Information System (INIS)

Rau, A.R.P.; Inokuti, M.

1997-01-01

The notion of the quantum defect is important in atomic and molecular spectroscopy and also in unifying spectroscopy with collision theory. In the latter context, the quantum defect may be viewed as an ancestor of the phase shift. However, the origin of the term quantum defect does not seem to be explained in standard textbooks. It occurred in a 1921 paper by Schroedinger, preceding quantum mechanics, yet giving the correct meaning as an index of the short-range interactions with the core of an atom. The authors present the early history of the quantum-defect idea, and sketch its recent developments

Defect characterization in high-purity silicon after γ- and hadron irradiation

International Nuclear Information System (INIS)

Stahl, J.

2004-07-01

The challenge for silicon particle detectors in future high energy physics experiments caused by extreme radiation fields can only be met by an appropriate defect engineering of the starting material. Appreciable improvements had already been obtained by enriching high resistivity float zone silicon with oxygen as demonstrated by the CERN RD48 collaboration. This thesis will focus on the difference observed after irradiation between standard and oxygenated float zone and detector grade Czochralski silicon. Results obtained with diodes manufactured on epitaxial layers are also included, envisioning effects arising from the possible migration of impurities during the crystal growth from the oxygen rich Czochralski substrate. Deep level transient spectroscopy (DLTS) and thermally stimulated current (TSC) measurements have been performed for defect characterization after γ- and hadron irradiation. Also a new high resolution DLTS technique has been used for the first time to separate defect levels with similar parameters. During the microscopic studies additionally to the well known defects like VO i , V 2 , C i O i or VP, four new radiation induced defects have been discovered and characterized. Two of these defects are closely correlated with the detector performance: A deep acceptor labeled as I-defect, and a bistable donor (BD). The formation of the I-defect is strongly suppressed in oxygen rich materials, while the formation of the BD is suppressed in oxygen lean material. With their properties the I- and the BD-defect are able to explain the different macroscopic behavior of standard and oxygen enriched float zone silicon after γ-irradiation. Furthermore, the BD defect is most probably responsible for the observation that in Cz and Epi diodes space charge sign inversion does not occur even after high fluences of proton irradiation. Additionally the γ-irradiated diodes were annealed at temperatures between 100 C and 350 C. During these studies some new reaction

Some remarks on defects and T-duality

DEFF Research Database (Denmark)

Sarkissian, Gor; Schweigert, Christoph

2009-01-01

The equations of motion for a conformal field theory in the presence of defect lines can be derived from an action that includes contributions from bibranes. For T-dual toroidal compactifications, they imply a direct relation between Poincaré line bundles and the action of T-duality on boundary...

Internal hydriding in irradiated defected Zircaloy fuel rods: A review (LWBR Development Program)

International Nuclear Information System (INIS)

Clayton, J.C.

1987-10-01

Although not a problem in recent commercial power reactors, including the Shippingport Light Water Breeder Reactor, internal hydriding of Zircaloy cladding was a persistent cause of gross cladding failures during the 1960s. It occurred in the fuel rods of water-cooled nuclear power reactors that had a small cladding defect. This report summarizes the experimental findings, causes, mechanisms, and methods of minimizing internal hydriding in defected Zircaloy-clad fuel rods. Irradiation test data on the different types of defected fuel rods, intentionally fabricated defected and in-pile operationally defected rods, are compared. Significant factors affecting internal hydriding in defected Zircaloy-clad fuel rods (defect hole size, internal and external sources of hydrogen, Zircaloy cladding surface properties, nickel alloy contamination of Zircaloy, the effect of heat flux and fluence) are discussed. Pertinent in-pile and out-of-pile test results from Bettis and other laboratories are used as a data base in constructing a qualitative model which explains hydrogen generation and distribution in Zircaloy cladding of defected water-cooled reactor fuel rods. Techniques for minimizing internal hydride failures in Zircaloy-clad fuel rods are evaluated

Defect relaxation in disordered materials

International Nuclear Information System (INIS)

Crandell, R.S.

1989-01-01

Using an exponential distribution of activation barriers, annealing data for metastable effects in hydrogenated amorphous silicon, a-Si:H, are quantitatively explained. This includes the stretched exponential time dependence of annealing and a Meyer-Neldel rule for the annealing time constant. An exponential distribution of annealing energies arises because defects are frozen in during growth at high temperature. Mechanisms that lead to an exponential distribution of annealing energies are weak bond-breaking and charge trapping

Modified classification and single-stage microsurgical repair of posttraumatic infected massive bone defects in lower extremities.

Science.gov (United States)

Yang, Yun-fa; Xu, Zhong-he; Zhang, Guang-ming; Wang, Jian-wei; Hu, Si-wang; Hou, Zhi-qi; Xu, Da-chuan

2013-11-01

Posttraumatic infected massive bone defects in lower extremities are difficult to repair because they frequently exhibit massive bone and/or soft tissue defects, serious bone infection, and excessive scar proliferation. This study aimed to determine whether these defects could be classified and repaired at a single stage. A total of 51 cases of posttraumatic infected massive bone defect in lower extremity were included in this study. They were classified into four types on the basis of the conditions of the bone defects, soft tissue defects, and injured limb length, including Type A (without soft tissue defects), Type B (with soft tissue defects of 10 × 20 cm or less), Type C (with soft tissue defects of 10 × 20 cm or more), and Type D (with the limb shortening of 3 cm or more). Four types of single-stage microsurgical repair protocols were planned accordingly and implemented respectively. These protocols included the following: Protocol A, where vascularized fibular graft was implemented for Type A; Protocol B, where vascularized fibular osteoseptocutaneous graft was implemented for Type B; Protocol C, where vascularized fibular graft and anterior lateral thigh flap were used for Type C; and Protocol D, where limb lengthening and Protocols A, B, or C were used for Type D. There were 12, 33, 4, and 2 cases of Types A, B, C, and D, respectively, according to this classification. During the surgery, three cases of planned Protocol B had to be shifted into Protocol C; however, all microsurgical repairs were completed. With reference to Johner-Wruhs evaluation method, the total percentage of excellent and good results was 82.35% after 6 to 41 months of follow-up. It was concluded that posttraumatic massive bone defects could be accurately classified into four types on the basis of the conditions of bone defects, soft tissue coverage, and injured limb length, and successfully repaired with the single-stage repair protocols after thorough debridement. Thieme Medical

Paternal occupation and birth defects: findings from the National Birth Defects Prevention Study.

NARCIS (Netherlands)

Desrosiers, T.A.; Herring, A.H.; Shapira, S.K.; Hooiveld, M.; Luben, T.J.; Herdt-Losavio, M.L.; Lin, S.; Olshan, A.F.

2012-01-01

Objectives: Several epidemiological studies have suggested that certain paternal occupations may be associated with an increased prevalence of birth defects in offspring. Using data from the National Birth Defects Prevention Study, the authors investigated the association between paternal occupation

[Inconformity between soft tissue defect and bony defect in incomplete cleft palate].

Science.gov (United States)

Zhou, Xia; Ma, Lian

2014-12-01

To evaluate the inconformity between soft tissue defect and bony defect by observing the cleft extent of palate with complete secondary palate bony cleft in incomplete cleft palate patient. The patients with incomplete cleft palate treated in Hospital of Stomatology Peking University from July 2012 to June 2013 were reviewed, of which 75 cases with complete secondary palate bony cleft were selected in this study. The CT scan and intraoral photograph were taken before operation. The patients were classified as four types according to the extent of soft tissue defect. Type 1: soft tissue defect reached incisive foremen region, Type 2 was hard and soft cleft palate, Type 3 soft cleft palate and Type 4 submucous cleft palate. Type 1 was defined as conformity group (CG). The other three types were defined as inconformity group (ICG) and divided into three subgroups (ICG-I), (ICG-II) and (ICG-III). Fifty-seven patients were in ICG group, and the rate of inconformity was 76% (57/75). The percentage of ICG-I, ICG-II and ICG-III was 47% (27/57), 23% (13/57) and 30% (17/57), respevtively. There are different types of soft tissue deformity with complete secondary palate bony cleft. The inconformity between soft tissue and hard tissue defect exits in 3/4 of isolated cleft palate patients.

Chemical characterisation of non-defective and defective green arabica and robusta coffees by electrospray ionization-mass spectrometry (ESI-MS).

Science.gov (United States)

Mendonça, Juliana C F; Franca, Adriana S; Oliveira, Leandro S; Nunes, Marcella

2008-11-15

The coffee roasted in Brazil is considered to be of low quality, due to the presence of defective coffee beans that depreciate the beverage quality. These beans, although being separated from the non-defective ones prior to roasting, are still commercialized in the coffee trading market. Thus, it was the aim of this work to verify the feasibility of employing ESI-MS to identify chemical characteristics that will allow the discrimination of Arabica and Robusta species and also of defective and non-defective coffees. Aqueous extracts of green (raw) defective and non-defective coffee beans were analyzed by direct infusion electrospray ionization mass spectrometry (ESI-MS) and this technique provided characteristic fingerprinting mass spectra that not only allowed for discrimination of species but also between defective and non-defective coffee beans. ESI-MS profiles in the positive mode (ESI(+)-MS) provided separation between defective and non-defective coffees within a given species, whereas ESI-MS profiles in the negative mode (ESI(-)-MS) provided separation between Arabica and Robusta coffees. Copyright © 2008 Elsevier Ltd. All rights reserved.

Defects and diffusion, theory & simulation II

CERN Document Server

Fisher, David J

2010-01-01

This second volume in a new series covering entirely general results in the fields of defects and diffusion includes 356 abstracts of papers which appeared between the end of 2009 and the end of 2010. As well as the abstracts, the volume includes original papers on theory/simulation, semiconductors and metals: ""Predicting Diffusion Coefficients from First Principles ..."" (Mantina, Chen & Liu), ""Gouge Assessment for Pipes ..."" (Meliani, Pluvinage & Capelle), ""Simulation of the Impact Behaviour of ... Hollow Sphere Structures"" (Ferrano, Speich, Rimkus, Merkel & Öchsner), ""Elastic-Plastic

Geometrically unrestricted, topologically constrained control of liquid crystal defects using simultaneous holonomic magnetic and holographic optical manipulation

Science.gov (United States)

Varney, Michael C. M.; Jenness, Nathan J.; Smalyukh, Ivan I.

2014-02-01

Despite the recent progress in physical control and manipulation of various condensed matter, atomic, and particle systems, including individual atoms and photons, our ability to control topological defects remains limited. Recently, controlled generation, spatial translation, and stretching of topological point and line defects have been achieved using laser tweezers and liquid crystals as model defect-hosting systems. However, many modes of manipulation remain hindered by limitations inherent to optical trapping. To overcome some of these limitations, we integrate holographic optical tweezers with a magnetic manipulation system, which enables fully holonomic manipulation of defects by means of optically and magnetically controllable colloids used as "handles" to transfer forces and torques to various liquid crystal defects. These colloidal handles are magnetically rotated around determined axes and are optically translated along three-dimensional pathways while mechanically attached to defects, which, combined with inducing spatially localized nematic-isotropic phase transitions, allow for geometrically unrestricted control of defects, including previously unrealized modes of noncontact manipulation, such as the twisting of disclination clusters. These manipulation capabilities may allow for probing topological constraints and the nature of defects in unprecedented ways, providing the foundation for a tabletop laboratory to expand our understanding of the role defects play in fields ranging from subatomic particle physics to early-universe cosmology.

The role of defects and doping in 2D graphene sheets and 1D nanoribbons.

Science.gov (United States)

Terrones, Humberto; Lv, Ruitao; Terrones, Mauricio; Dresselhaus, Mildred S

2012-06-01

Defects are usually seen as imperfections in materials that could significantly degrade their performance. However, at the nanoscale, defects could be extremely useful since they could be exploited to generate novel, innovative and useful materials and devices. Graphene and graphene nanoribbons are no exception. This review therefore tries to categorize defects, emphasize their importance, introduce the common routes to study and identify them and to propose new ways to construct novel devices based on 'defective' graphene-like materials. In particular, we will discuss defects in graphene-like systems including (a) structural (sp(2)-like) defects, (b) topological (sp(2)-like) defects, (c) doping or functionalization (sp(2)- and sp(3)-like) defects and (d) vacancies/edge type defects (non-sp(2)-like). It will be demonstrated that defects play a key role in graphene physicochemical properties and could even be critical to generate biocompatible materials. There are numerous challenges in this emerging field, and we intend to provide a stimulating account which could trigger new science and technological developments based on defective graphene-like materials that could be introduced into other atomic layered materials, such as BN, MoS(2) and WS(2), not discussed in this review.

24 CFR 3288.20 - Reporting a defect.

Science.gov (United States)

2010-04-01

... writing, including, but not limited to, e-mail, written letter, certified mail, or fax. The existence of... email. Persons who report an alleged defect by telephone should make a contemporaneous note of the... made using any of the following methods: (1) In writing at: HUD, Office of Regulatory Affairs and...

Topological defects from the multiverse

Science.gov (United States)

Zhang, Jun; Blanco-Pillado, Jose J.; Garriga, Jaume; Vilenkin, Alexander

2015-05-01

Many theories of the early universe predict the existence of a multiverse where bubbles continuously nucleate giving rise to observers in their interior. In this paper, we point out that topological defects of several dimensionalities will also be produced in de Sitter like regions of the multiverse. In particular, defects could be spontaneously nucleated in our parent vacuum. We study the evolution of these defects as they collide with and propagate inside of our bubble. We estimate the present distribution of defects in the observable part of the universe. The expected number of such nearby defects turns out to be quite small, even for the highest nucleation rate. We also study collisions of strings and domain walls with our bubble in our past light cone. We obtain simulated full-sky maps of the loci of such collisions, and find their angular size distribution. Similarly to what happens in the case of bubble collisions, the prospect of detecting any collisions of our bubble with ambient defects is greatly enhanced in the case where the cosmological constant of our parent vacuum is much higher than the vacuum energy density during inflation in our bubble.

Topological defects from the multiverse

Energy Technology Data Exchange (ETDEWEB)

Zhang, Jun [Institute of Cosmology, Department of Physics and Astronomy, Tufts University, Medford, MA 02155 (United States); Blanco-Pillado, Jose J. [Department of Theoretical Physics, University of the Basque Country UPV/EHU, 48080 Bilbao (Spain); IKERBASQUE, Basque Foundation for Science, 48013, Bilbao (Spain); Garriga, Jaume [Departament de Fisica Fonamental i Institut de Ciencies del Cosmos, Universitat de Barcelona, Marti i Franques, 1, 08028, Barcelona (Spain); Vilenkin, Alexander [Institute of Cosmology, Department of Physics and Astronomy, Tufts University, Medford, MA 02155 (United States)

2015-05-28

Many theories of the early universe predict the existence of a multiverse where bubbles continuously nucleate giving rise to observers in their interior. In this paper, we point out that topological defects of several dimensionalities will also be produced in de Sitter like regions of the multiverse. In particular, defects could be spontaneously nucleated in our parent vacuum. We study the evolution of these defects as they collide with and propagate inside of our bubble. We estimate the present distribution of defects in the observable part of the universe. The expected number of such nearby defects turns out to be quite small, even for the highest nucleation rate. We also study collisions of strings and domain walls with our bubble in our past light cone. We obtain simulated full-sky maps of the loci of such collisions, and find their angular size distribution. Similarly to what happens in the case of bubble collisions, the prospect of detecting any collisions of our bubble with ambient defects is greatly enhanced in the case where the cosmological constant of our parent vacuum is much higher than the vacuum energy density during inflation in our bubble.

Topological defects from the multiverse

International Nuclear Information System (INIS)

Zhang, Jun; Vilenkin, Alexander; Blanco-Pillado, Jose J.; Garriga, Jaume

2015-01-01

Many theories of the early universe predict the existence of a multiverse where bubbles continuously nucleate giving rise to observers in their interior. In this paper, we point out that topological defects of several dimensionalities will also be produced in de Sitter like regions of the multiverse. In particular, defects could be spontaneously nucleated in our parent vacuum. We study the evolution of these defects as they collide with and propagate inside of our bubble. We estimate the present distribution of defects in the observable part of the universe. The expected number of such nearby defects turns out to be quite small, even for the highest nucleation rate. We also study collisions of strings and domain walls with our bubble in our past light cone. We obtain simulated full-sky maps of the loci of such collisions, and find their angular size distribution. Similarly to what happens in the case of bubble collisions, the prospect of detecting any collisions of our bubble with ambient defects is greatly enhanced in the case where the cosmological constant of our parent vacuum is much higher than the vacuum energy density during inflation in our bubble

Metastable gravity on classical defects

International Nuclear Information System (INIS)

Ringeval, Christophe; Rombouts, Jan-Willem

2005-01-01

We discuss the realization of metastable gravity on classical defects in infinite-volume extra dimensions. In dilatonic Einstein gravity, it is found that the existence of metastable gravity on the defect core requires violation of the dominant energy condition for codimension N c =2 defects. This is illustrated with a detailed analysis of a six-dimensional hyperstring minimally coupled to dilaton gravity. We present the general conditions under which a codimension N c >2 defect admits metastable modes, and find that they differ from lower codimensional models in that, under certain conditions, they do not require violation of energy conditions to support quasilocalized gravity

Observation and analysis of defect cluster production and interactions with dislocations

International Nuclear Information System (INIS)

Zinkle, S.J.; Matsukawa, Y.

2004-01-01

The current understanding of defect production fundamentals in neutron-irradiated face centered cubic (FCC) and body centered cubic (BCC) metals is briefly reviewed, based primarily on transmission electron microscope observations. Experimental procedures developed by Michio Kiritani and colleagues have been applied to quantify defect cluster size, density, and nature. Differences in defect accumulation behavior of irradiated BCC and FCC metals are discussed. Depending on the defect cluster obstacle strength, either the dispersed barrier hardening model or the Friedel-Kroupa-Hirsch weak barrier model can be used to describe major aspects of radiation hardening. Irradiation at low temperature can cause a change in deformation mode from dislocation cell formation at low doses to twinning or dislocation channeling at higher doses. The detailed interaction between dislocations and defect clusters helps determine the dominant deformation mode. Recent observations of the microstructure created by plastic deformation of quenched and irradiated metals are summarized, including in situ deformation results. Examples of annihilation of stacking fault tetrahedra by gliding dislocations and subsequent formation of mobile superjogs are shown

Point-defect migration into an infinitesimal dislocation loop

International Nuclear Information System (INIS)

Woo, C.H.

1981-11-01

Point-defect migration into an infinitesimal dislocation loop in an isotropic linear elastic medium is described. Particular care has been taken to include the effects of the saddle-point shape anisotropy of the point defect. Expressions for the reaction radii and the bias are derived, both in the presence and absence of an external applied stress. These are found to depend on intrinsic parameters, such as the loop strength, the loop nature (vacancy or interstitial), the relaxation volume, the saddle-point shape, and extrinsic parameters, such as the magnitude and direction of the external stress, and the temperature. The implications of the results are discussed

Gerbode defect: A comprehensive review of its history, anatomy, embryology, pathophysiology, diagnosis, and treatment

Directory of Open Access Journals (Sweden)

Erfanul Saker

2017-10-01

Full Text Available The purpose of this paper is to survey the literature on Gerbode defect and provide an overview of its history, anatomy, development, pathophysiology, diagnosis, and treatment options. The available literature on this topic, including case reports, was thoroughly reviewed. Gerbode defect is defined as abnormal shunting between the left ventricle and right atrium resulting from either a congenital defect or prior cardiac insults. The pathophysiology underlying the development of Gerbode defect is a disease process that injures the atrioventricular septum and leads to the abnormal shunting of blood. Although the most prevalent cause of Gerbode defect has historically been congenital, an increasing trend towards acquired cases has recently been reported owing to improved diagnostic capabilities and a greater number of invasive cardiac procedures. In conclusion, Gerbode defect is an increasingly recognized condition that warrants further study.

Fabrication of a hollow bulb prosthesis for the rehabilitation of an acquired total maxillectomy defect

Science.gov (United States)

Vamsi Krishna, C H; Babu, Jaya Krishna; Fathima, Tanveer; Reddy, G V K

2014-01-01

The prosthodontic rehabilitation of maxillary defects is a challenging and demanding task which requires careful pre-surgical and post-surgical planning. Maxillary defects can be congenital or acquired. Acquired defects include those following trauma or surgical treatment of benign or malignant neoplasms. A prosthodontist encounters problems such as absence of support, poor retention, and lack of prosthesis stability in treating these patients. The present case report describes a procedure to fabricate a definitive hollow bulb obturator prosthesis for the rehabilitation of a total maxillectomy defect. PMID:24671313

Defects in new protective aprons

International Nuclear Information System (INIS)

Glaze, S.; LeBlanc, A.D.; Bushong, S.C.

1984-01-01

Upon careful examination, several defects have been detected in new protective aprons. The nature of the defects is identified and described. Although the occurrence of such defects has not exceeded 5%, they are significant enough to warrant return of the lead apron to the supplier. It is recommended that the integrity of all new protective aprons be verified upon receipt as well as at yearly intervals

Do NiTi instruments show defects before separation? Defects caused by torsional fatigue in hand and rotary nickel-titanium (NiTi) instruments which lead to failure during clinical use.

Science.gov (United States)

Chakka, N V Murali Krishna; Ratnakar, P; Das, Sanjib; Bagchi, Anandamy; Sudhir, Sudhir; Anumula, Lavanya

2012-11-01

Visual and microscopic evaluation of defects caused by torsional fatigue in hand and rotary nickel titanium (NiTi) instruments. Ninety-six NiTi greater taper instruments which were routinely used for root canal treatment only in anterior teeth were selected for the study. The files taken include ProTaper for hand use, ProTaper Rotary files and Endowave rotary files. After every use, the files were observed visually and microscopically (Stereomicroscope at 10×) to evaluate the defects caused by torsional fatigue. Scoring was given according to a new classification formulated which gives an indication of the severity of the defect or damage. Data was statistically analyzed using KruskallWallis and Mann-Whitney U test. Number of files showing defects were more under stereomicroscope than visual examination. But, the difference in the evaluation methods was not statistically significant. The different types of defects observed were bent instrument, straightening/stretching of twist contour and partial reverse twisting. Endowave files showed maximum number of defects followed by ProTaper for hand use and least in ProTaper Rotary. Visible defects due to torsional fatigue do occur in NiTi instruments after clinical use. Both visual and microscopic examinations were efficient in detecting defects caused due to torsional fatigue. This study emphasizes that all files should be observed for any visible defects before and after every instrumentation cycle to minimize the risk of instrument separation and failure of endodontic therapy.

Little string origin of surface defects

Energy Technology Data Exchange (ETDEWEB)

Haouzi, Nathan; Schmid, Christian [Center for Theoretical Physics, University of California, Berkeley,LeConte Hall, Berkeley (United States)

2017-05-16

We derive a large class of codimension-two defects of 4d N=4 Super Yang-Mills (SYM) theory from the (2,0) little string. The origin of the little string is type IIB theory compactified on an ADE singularity. The defects are D-branes wrapping the 2-cycles of the singularity. We use this construction to make contact with the description of SYM defects due to Gukov and Witten https://arxiv.org/abs/hep-th/0612073. Furthermore, we provide a geometric perspective on the nilpotent orbit classification of codimension-two defects, and the connection to ADE-type Toda CFT. The only data needed to specify the defects is a set of weights of the algebra obeying certain constraints, which we give explicitly. We highlight the differences between the defect classification in the little string theory and its (2,0) CFT limit.

Various Stone-Wales defects in phagraphene

Science.gov (United States)

Openov, L. A.; Podlivaev, A. I.

2016-08-01

Various Stone-Wales defects in phagraphene, which is a graphene allotrope, predicted recently are studied in terms of the nonorthogonal tight-binding model. The energies of the defect formation and the heights of energy barriers preventing the formation and annealing of the defects are found. Corresponding frequency factors in the Arrhenius formula are calculated. The evolution of the defect structure is studied in the real-time mode using the molecular dynamics method.

Defect identification in semiconductors with positron annihilation: experiment and theory

Science.gov (United States)

Tuomisto, Filip

2015-03-01

Positron annihilation spectroscopy is a very powerful technique for the detection, identification and quantification of vacancy-type defects in semiconductors. In the past decades, it has been used to reveal the relationship between opto-electronic properties and specific defects in a wide variety of materials - examples include parasitic yellow luminescence in GaN, dominant acceptor defects in ZnO and broad-band absorption causing brown coloration in natural diamond. In typical binary compound semiconductors, the selective sensitivity of the technique is rather strongly limited to cation vacancies that possess significant open volume and suitable charge (negative of neutral). On the other hand, oxygen vacancies in oxide semiconductors are a widely debated topic. The properties attributed to oxygen vacancies include the inherent n-type conduction, poor p-type dopability, coloration (absorption), deep level luminescence and non-radiative recombination, while the only direct experimental evidence of their existence has been obtained on the crystal surface. We will present recent advances in combining state-of-the-art positron annihilation experiments and ab initio computational approaches. The latter can be used to model both the positron lifetime and the electron-positron momentum distribution - quantities that can be directly compared with experimental results. We have applied these methods to study vacancy-type defects in III-nitride semiconductors (GaN, AlN, InN) and oxides such as ZnO, SnO2, In2O3andGa2O3. We will show that cation-vacancy-related defects are important compensating centers in all these materials when they are n-type. In addition, we will show that anion (N, O) vacancies can be detected when they appear as complexes with cation vacancies.

Heat-Treatment of Defective UiO-66 from Modulated Synthesis: Adsorption and Stability Studies

International Nuclear Information System (INIS)

Jiao, Yang; Liu, Yang; Zhu, Guanghui; Hungerford, Julian T.; Bhattacharyya, Souryadeep

2017-01-01

Defect engineering in metal-organic frameworks (MOFs) is an emerging strategy that can be used to control physical or chemical characteristics of MOFs, including adsorption behavior and textural, mechanical, and conductive properties. Understanding the impact of defects on textural properties and chemical stability of MOFs is imperative to the development of MOFs with tunable defect sites. In this work, systematic adsorption measurements were performed with three adsorbate molecules (SO 2 , benzene, and cyclohexane) to investigate changes in the pore size of defective UiO-66. Compared to the parent UiO-66, the defective UiO-66 shows significant changes in adsorption capacities among the selected adsorbate molecules, demonstrating that pore size is significantly enlarged by the missing cluster defects. BET surface area analysis and DFT calculations were also performed to interrogate the chemical stability of the defective MOFs after exposure to water and acidic environments. This work shows that pore size can be tuned as a function of defect concentration. Further, it is shown that the structural incorporation of trifluoroacetate groups in defective UiO-66 leads to an increase in average pore size without sacrificing chemical stability toward water and acidic species. The results of this work advance the understanding of textural properties and chemical stability of defect-engineered MOFs and also suggest a preparation method for synthesizing defective but stable MOFs.

Closure of Myelomeningocele Defects Using a Limberg Flap or Direct Repair

Directory of Open Access Journals (Sweden)

Jung-Hwan Shim

2016-01-01

Full Text Available BackgroundThe global prevalence of myelomeningocele has been reported to be 0.8–1 per 1,000 live births. Early closure of the defect is considered to be the standard of care. Various surgical methods have been reported, such as primary skin closure, local skin flaps, musculocutaneous flaps, and skin grafts. The aim of this study was to describe the clinical characteristics of myelomeningocele defects and present the surgical outcomes of recent cases of myelomeningocele at our institution.MethodsPatients who underwent surgical closure of myelomeningocele at our institution from January 2004 to December 2013 were included in this study. A retrospective chart review of their medical records was performed, and comorbidities, defect size, location, surgical procedures, complications, and the final results were analyzed.ResultsA total of 14 patients underwent surgical closure for myelomeningocele defects. Twelve cases were closed with direct skin repair, while two cases required local skin flaps to cover the skin defects. Three cases of infection occurred, requiring incision and either drainage or removal of allogenic materials. One case of partial flap necrosis occurred, requiring secondary revision using a rotational flap and a full-thickness skin graft. Despite these complications, all wounds eventually healed completely.ConclusionsMost myelomeningocele defects can be managed by direct skin repair alone. In cases of large defects, in which direct repair is not possible, local flaps may be used to cover the defect. Complications such as wound dehiscence and partial flap necrosis occurred in this study; however, all such complications were successfully managed with simple ancillary procedures.

Quantum computing with defects.

Science.gov (United States)

Weber, J R; Koehl, W F; Varley, J B; Janotti, A; Buckley, B B; Van de Walle, C G; Awschalom, D D

2010-05-11

Identifying and designing physical systems for use as qubits, the basic units of quantum information, are critical steps in the development of a quantum computer. Among the possibilities in the solid state, a defect in diamond known as the nitrogen-vacancy (NV(-1)) center stands out for its robustness--its quantum state can be initialized, manipulated, and measured with high fidelity at room temperature. Here we describe how to systematically identify other deep center defects with similar quantum-mechanical properties. We present a list of physical criteria that these centers and their hosts should meet and explain how these requirements can be used in conjunction with electronic structure theory to intelligently sort through candidate defect systems. To illustrate these points in detail, we compare electronic structure calculations of the NV(-1) center in diamond with those of several deep centers in 4H silicon carbide (SiC). We then discuss the proposed criteria for similar defects in other tetrahedrally coordinated semiconductors.

Charged Semiconductor Defects Structure, Thermodynamics and Diffusion

CERN Document Server

Seebauer, Edmund G

2009-01-01

The technologically useful properties of a solid often depend upon the types and concentrations of the defects it contains. Not surprisingly, defects in semiconductors have been studied for many years, in many cases with a view towards controlling their behavior through various forms of "defect engineering." For example, in the bulk, charging significantly affects the total concentration of defects that are available to mediate phenomena such as solid-state diffusion. Surface defects play an important role in mediating surface mass transport during high temperature processing steps such as epitaxial film deposition, diffusional smoothing in reflow, and nanostructure formation in memory device fabrication. Charged Semiconductor Defects details the current state of knowledge regarding the properties of the ionized defects that can affect the behavior of advanced transistors, photo-active devices, catalysts, and sensors. Features: Group IV, III-V, and oxide semiconductors; Intrinsic and extrinsic defects; and, P...

Syndromes and Disorders Associated with Omphalocele (III: Single Gene Disorders, Neural Tube Defects, Diaphragmatic Defects and Others

Directory of Open Access Journals (Sweden)

Chih-Ping Chen

2007-06-01

Full Text Available Omphalocele can be associated with single gene disorders, neural tube defects, diaphragmatic defects, fetal valproate syndrome, and syndromes of unknown etiology. This article provides a comprehensive review of omphalocele-related disorders: otopalatodigital syndrome type II; Melnick–Needles syndrome; Rieger syndrome; neural tube defects; Meckel syndrome; Shprintzen–Goldberg omphalocele syndrome; lethal omphalocele-cleft palate syndrome; cerebro-costo-mandibular syndrome; fetal valproate syndrome; Marshall–Smith syndrome; fibrochondrogenesis; hydrolethalus syndrome; Fryns syndrome; omphalocele, diaphragmatic defects, radial anomalies and various internal malformations; diaphragmatic defects, limb deficiencies and ossification defects of skull; Donnai–Barrow syndrome; CHARGE syndrome; Goltz syndrome; Carpenter syndrome; Toriello–Carey syndrome; familial omphalocele; Cornelia de Lange syndrome; C syndrome; Elejalde syndrome; Malpuech syndrome; cervical ribs, Sprengel anomaly, anal atresia and urethral obstruction; hydrocephalus with associated malformations; Kennerknecht syndrome; lymphedema, atrial septal defect and facial changes; and craniosynostosis- mental retardation syndrome of Lin and Gettig. Perinatal identification of omphalocele should alert one to the possibility of omphalocele-related disorders and familial inheritance and prompt a thorough genetic counseling for these disorders.

Application of elastic net and infrared spectroscopy in the discrimination between defective and non-defective roasted coffees.

Science.gov (United States)

Craig, Ana Paula; Franca, Adriana S; Oliveira, Leandro S; Irudayaraj, Joseph; Ileleji, Klein

2014-10-01

The quality of the coffee beverage is negatively affected by the presence of defective coffee beans and its evaluation still relies on highly subjective sensory panels. To tackle the problem of subjectivity, sophisticated analytical techniques have been developed and have been shown capable of discriminating defective from non-defective coffees after roasting. However, these techniques are not adequate for routine analysis, for they are laborious (sample preparation) and time consuming, and reliable, simpler and faster techniques need to be developed for such purpose. Thus, it was the aim of this study to evaluate the performance of infrared spectroscopic methods, namely FTIR and NIR, for the discrimination of roasted defective and non-defective coffees, employing a novel statistical approach. The classification models based on Elastic Net exhibited high percentage of correct classification, and the discriminant infrared spectra variables extracted provided a good interpretation of the models. The discrimination of defective and non-defective beans was associated with main chemical descriptors of coffee, such as carbohydrates, proteins/amino acids, lipids, caffeine and chlorogenic acids. Copyright © 2014 Elsevier B.V. All rights reserved.

Communication: The electronic entropy of charged defect formation and its impact on thermochemical redox cycles

Science.gov (United States)

Lany, Stephan

2018-02-01

The ideal material for solar thermochemical water splitting, which has yet to be discovered, must satisfy stringent conditions for the free energy of reduction, including, in particular, a sufficiently large positive contribution from the solid-state entropy. By inverting the commonly used relationship between defect formation energy and defect concentration, it is shown here that charged defect formation causes a large electronic entropy contribution manifesting itself as the temperature dependence of the Fermi level. This result is a general feature of charged defect formation and motivates new materials design principles for solar thermochemical hydrogen production.

The Co-Occurrence of Autism and Birth Defects: Prevalence and Risk in a Population-Based Cohort

Science.gov (United States)

Schendel, Diana E.; Autry, Andrew; Wines, Roberta; Moore, Cynthia

2009-01-01

Aim: To estimate the prevalence of major birth defects among children with autism, the prevalence of autism in children with birth defects, and the risk for autism associated with having birth defects. Method: Retrospective cohort including all children born in Atlanta, GA, USA, 1986 to 1993, who survived to age 3 years and were identified through…

Magnetoencephalography signals are influenced by skull defects.

Science.gov (United States)

Lau, S; Flemming, L; Haueisen, J

2014-08-01

Magnetoencephalography (MEG) signals had previously been hypothesized to have negligible sensitivity to skull defects. The objective is to experimentally investigate the influence of conducting skull defects on MEG and EEG signals. A miniaturized electric dipole was implanted in vivo into rabbit brains. Simultaneous recording using 64-channel EEG and 16-channel MEG was conducted, first above the intact skull and then above a skull defect. Skull defects were filled with agar gels, which had been formulated to have tissue-like homogeneous conductivities. The dipole was moved beneath the skull defects, and measurements were taken at regularly spaced points. The EEG signal amplitude increased 2-10 times, whereas the MEG signal amplitude reduced by as much as 20%. The EEG signal amplitude deviated more when the source was under the edge of the defect, whereas the MEG signal amplitude deviated more when the source was central under the defect. The change in MEG field-map topography (relative difference measure, RDM(∗)=0.15) was geometrically related to the skull defect edge. MEG and EEG signals can be substantially affected by skull defects. MEG source modeling requires realistic volume conductor head models that incorporate skull defects. Copyright © 2013 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

Meiotic sex ratio variation in natural populations of Ceratodon purpureus (Ditrichaceae).

Science.gov (United States)

Norrell, Tatum E; Jones, Kelly S; Payton, Adam C; McDaniel, Stuart F

2014-09-01

• Sex ratio variation is a common but often unexplained phenomenon in species across the tree of life. Here we evaluate the hypothesis that meiotic sex ratio variation can contribute to the biased sex ratios found in natural populations of the moss Ceratodon purpureus.• We obtained sporophytes from several populations of C. purpureus from eastern North America. From each sporophyte, we estimated the mean spore viability by germinating replicate samples on agar plates. We estimated the meiotic sex ratio of each sporophyte by inferring the sex of a random sample of germinated spores (mean = 77) using a PCR-RFLP test. We tested for among-sporophyte variation in viability using an ANOVA and for deviations from 1:1 sex ratio using a χ(2)-test and evaluated the relationship between these quantities using a linear regression.• We found among-sporophyte variation in spore viability and meiotic sex ratio, suggesting that genetic variants that contribute to variation in both of these traits segregate within populations of this species. However, we found no relationship between these quantities, suggesting that factors other than sex ratio distorters contribute to variation in spore viability within populations.• These results demonstrate that sex ratio distortion may partially explain the population sex ratio variation seen in C. purpureus, but more generally that genetic conflict over meiotic segregation may contribute to fitness variation in this species. Overall, this study lays the groundwork for future studies on the genetic basis of meiotic sex ratio variation. © 2014 Botanical Society of America, Inc.

Understanding mechanisms of rarity in pteridophytes: competition and climate change threaten the rare fern Asplenium scolopendrium var. americanum (Aspleniaceae).

Science.gov (United States)

Testo, Weston L; Watkins, James E

2013-11-01

Understanding the ecology of rare species can inform aspects of conservation strategies; however, the mechanisms of rarity remain elusive for most pteridophytes, which possess independent and ecologically distinct gametophyte and sporophyte generations. To elucidate factors contributing to recent declines of the rare fern Asplenium scolopendrium var. americanum, we studied the ecology and ecophysiology of its gametophyte generation, focusing on responses to competition, temperature, and water stress. Gametophytes of A. scolopendrium var. americanum, its widespread European relative A. scolopendrium var. scolopendrium, and five co-occurring fern species were grown from spores. Gametophytes were grown at 20°C and 25°C, and germination rates, intra- and interspecific competition, desiccation tolerance, and sporophyte production were determined for all species. Gametophytes of A. scolopendrium var. americanum had the lowest rates of germination and sporophyte production among all species studied and exhibited the greatest sensitivity to interspecific competition, temperature increases, and desiccation. Mature gametophytes of A. scolopendrium var. americanum grown at 25°C were 84.6% smaller than those grown at 20°C, and only 1.5% produced sporophytes after 200 d in culture. Similar responses were not observed in other species studied. The recent declines and current status of populations of A. scolopendrium var. americanum are linked to its gametophyte's limited capacity to tolerate competition and physiological stress linked to climate change. This is the first study to develop a mechanistic understanding of rarity and decline in a fern and demonstrates the importance of considering the ecology of the gametophyte in plants with independent sporophyte and gametophyte generations.

Enhancing native defect sensitivity for EUV actinic blank inspection: optimized pupil engineering and photon noise study

Science.gov (United States)

Wang, Yow-Gwo; Neureuther, Andrew; Naulleau, Patrick

2016-03-01

In this paper, we discuss the impact of optimized pupil engineering and photon noise on native defect sensitivity in EUV actinic blank inspection. Native defects include phase-dominated defects, absorber defects, and defects with a combination of phase and absorption behavior. First, we extend the idea of the Zernike phase contrast (ZPC) method and study the impact of optimum phase shift in the pupil plane on native defect sensitivity, showing a 23% signal-to-noise ratio (SNR) enhancement compare to bright field (BF) for a phase defect with 20% absorption. We also describe the possibility to increase target defect SNR on target defect sizes at the price of losing the sensitivity on smaller (non-critical) defects. Moreover, we show the advantage of the optimized phase contrast (OZPC) method over BF EUV actinic blank inspection. A single focus scan from OZPC has better inspection efficiency over BF. Second, we make a detailed comparison between the phase contrast with apodization (AZPC) method and dark field (DF) method based on defect sensitivity in the presence of both photon shot noise and camera noise. Performance is compared for a variety of photon levels, mask roughness conditions, and combinations of defect phase and absorption.

Electrical fingerprint of pipeline defects

International Nuclear Information System (INIS)

Mica, Isabella; Polignano, Maria Luisa; Marco, Cinzia De

2004-01-01

Pipeline defects are dislocations that connect the source region of the transistor with the drain region. They were widely reported to occur in CMOS, BiCMOS devices and recently in SOI technologies. They can reduce device yield either by affecting the devices functionality or by increasing the current consumption under stand-by conditions. In this work the electrical fingerprint of these dislocations is studied, its purpose is to enable us to identify these defects as the ones responsible for device failure. It is shown that the pipeline defects are responsible for a leakage current from source to drain in the transistors. This leakage has a resistive characteristic and it is lightly modulated by the body bias. It is not sensitive to temperature; vice versa the off-current of a good transistor exhibits the well-known exponential dependence on 1/T. The emission spectrum of these defects was studied and compared with the spectrum of a good transistor. The paper aims to show that the spectrum of a defective transistor is quite peculiar; it shows well defined peaks, whereas the spectrum of a good transistor under saturation conditions is characterized by a broad spectral light emission distribution. Finally the deep-level transient spectroscopy (DLTS) is tried on defective diodes

A study of process-related electrical defects in SOI lateral bipolar transistors fabricated by ion implantation

Science.gov (United States)

Yau, J.-B.; Cai, J.; Hashemi, P.; Balakrishnan, K.; D'Emic, C.; Ning, T. H.

2018-04-01

We report a systematic study of process-related electrical defects in symmetric lateral NPN transistors on silicon-on-insulator (SOI) fabricated using ion implantation for all the doped regions. A primary objective of this study is to see if pipe defects (emitter-collector shorts caused by locally enhanced dopant diffusion) are a show stopper for such bipolar technology. Measurements of IC-VCE and Gummel currents in parallel-connected transistor chains as a function of post-fabrication rapid thermal anneal cycles allow several process-related electrical defects to be identified. They include defective emitter-base and collector-base diodes, pipe defects, and defects associated with a dopant-deficient region in an extrinsic base adjacent its intrinsic base. There is no evidence of pipe defects being a major concern in SOI lateral bipolar transistors.

Defect spectroscopy of single ZnO microwires

Science.gov (United States)

Villafuerte, M.; Ferreyra, J. M.; Zapata, C.; Barzola-Quiquia, J.; Iikawa, F.; Esquinazi, P.; Heluani, S. P.; de Lima, M. M.; Cantarero, A.

2014-04-01

The point defects of single ZnO microwires grown by carbothermal reduction were studied by microphotoluminescence, photoresistance excitation spectra, and resistance as a function of the temperature. We found the deep level defect density profile along the microwire showing that the concentration of defects decreases from the base to the tip of the microwires and this effect correlates with a band gap narrowing. The results show a characteristic deep defect levels inside the gap at 0.88 eV from the top of the VB. The resistance as a function of the temperature shows defect levels next to the bottom of the CB at 110 meV and a mean defect concentration of 4 × 1018 cm-3. This combination of techniques allows us to study the band gap values and defects states inside the gap in single ZnO microwires and opens the possibility to be used as a defect spectroscopy method.

A Study on the Effects of Ball Defects on the Fatigue Life in Hybrid Bearings

Science.gov (United States)

Tang, Ching-Yao; Foerster, Chad E.; O'Brien, Michael J.; Hardy, Brian S.; Goyal, Vinay K.; Nelson, Benjamin A.; Robinson, Ernest Y.; Ward, Peter C.; Hilton, Michael R.

2014-01-01

Hybrid ball bearings using silicon nitride ceramic balls with steel rings are increasingly being used in space mechanism applications due to their high wear resistance and long rolling contact fatigue life. However, qualitative and quantitative reports of the effects of ball defects that cause early fatigue failure are rare. We report on our approach to study these effects. Our strategy includes characterization of defects encountered in use, generation of similar defects in a laboratory setting, execution of full-scale bearing tests to obtain lifetimes, post-test characterization, and related finite-element modeling to understand the stress concentration of these defects. We have confirmed that at least one type of defect of appropriate size can significantly reduce fatigue life. Our method can be used to evaluate other defects as they occur or are encountered.

Defect properties from X-ray scattering experiments

International Nuclear Information System (INIS)

Peisl, H.

1976-01-01

Lattice distortions due to defects in crystals can be studied most directly by elastic X-ray or neutron scattering experiments. The 'size' of the defects can be determined from the shift of the Bragg reflections. Defect induced diffuse scattering intensity close to and between Bragg reflections gives information on the strength and symmetry of the distortion fields and yields the atomic structure of point defects (interstitials, vacancies, small aggregates). Diffuse scattering is a very sensitive method to decide whether defects are present as isolated point defects or have formed aggregates. X-ray scattering has been used to study defects produced in various ionic crystals by γ- and neutron irradiation. After an introduction to the principles of the method the experimental results will be reviewed and discussed in some detail. (orig.) [de

Modeling of Powder Bed Manufacturing Defects

Science.gov (United States)

Mindt, H.-W.; Desmaison, O.; Megahed, M.; Peralta, A.; Neumann, J.

2018-01-01

Powder bed additive manufacturing offers unmatched capabilities. The deposition resolution achieved is extremely high enabling the production of innovative functional products and materials. Achieving the desired final quality is, however, hampered by many potential defects that have to be managed in due course of the manufacturing process. Defects observed in products manufactured via powder bed fusion have been studied experimentally. In this effort we have relied on experiments reported in the literature and—when experimental data were not sufficient—we have performed additional experiments providing an extended foundation for defect analysis. There is large interest in reducing the effort and cost of additive manufacturing process qualification and certification using integrated computational material engineering. A prerequisite is, however, that numerical methods can indeed capture defects. A multiscale multiphysics platform is developed and applied to predict and explain the origin of several defects that have been observed experimentally during laser-based powder bed fusion processes. The models utilized are briefly introduced. The ability of the models to capture the observed defects is verified. The root cause of the defects is explained by analyzing the numerical results thus confirming the ability of numerical methods to provide a foundation for rapid process qualification.

Talbot effect of the defective grating in deep Fresnel region

Science.gov (United States)

Teng, Shuyun; Wang, Junhong; Zhang, Wei; Cui, Yuwei

2015-02-01

Talbot effect of the grating with different defect is studied theoretically and experimentally in this paper. The defects of grating include the loss of the diffraction unit, the dislocation of the diffraction unit and the modulation of the unit separation. The exact diffraction distributions of three kinds of defective gratings are obtained according to the finite-difference time-domain (FDTD) method. The calculation results show the image of the missing or dislocating unit appears at the Talbot distance (as mentioned in K. Patorski Prog. Opt., 27, 1989, pp.1-108). This is the so-called self-repair ability of grating imaging. In addition, some more phenomena are discovered. The loss or the dislocation of diffraction unit causes the diffraction distortion within a certain radial angle. The regular modulation of unit separation changes the original diffraction, but the new periodicity of the diffraction distribution rebuilds. The self-imaging of grating with smaller random modulation still keeps the partial self-repair ability, and yet this characteristic depends on the modulation degree of defective grating. These diffraction phenomena of the defective gratings are explained by use of the diffraction theory of grating. The practical experiment is also performed and the experimental results confirm the theoretic predictions.

The incidence and functional consequences of RT-associated cardiac perfusion defects

International Nuclear Information System (INIS)

Marks, Lawrence B.; Yu Xiaoli; Prosnitz, Robert G.; Zhou Sumin; Hardenbergh, Patricia H.; Blazing, Michael; Hollis, Donna; Lind, Pehr; Tisch, Andrea; Wong, Terence Z.; Borges-Neto, Salvador

2005-01-01

Purpose: Radiation therapy (RT) for left-sided breast cancer has been associated with cardiac dysfunction. We herein assess the temporal nature and volume dependence of RT-induced left ventricular perfusion defects and whether these perfusion defects are related to changes in cardiac wall motion or alterations in ejection fraction. Methods: From 1998 to 2001, 114 patients were enrolled onto an IRB-approved prospective clinical study to assess changes in regional and global cardiac function after RT for left-sided breast cancer. Patients were imaged 30 to 60 minutes after injection of technetium 99m sestamibi or tetrofosmin. Post-RT perfusion scans were compared with the pre-RT studies to assess for RT-induced perfusion defects as well as functional changes in wall motion and ejection fraction. Two-tailed Fisher's exact test and the Cochran-Armitage test for linear trends were used for statistical analysis. Results: The incidence of new perfusion defects 6, 12, 18, and 24 months after RT was 27%, 29%, 38%, and 42%, respectively. New defects occurred in approximately 10% to 20% and 50% to 60% of patients with less than 5%, and greater than 5%, of their left ventricle included within the RT fields, respectively (p = 0.33 to 0.00008). The rates of wall motion abnormalities in patients with and without perfusion defects were 12% to 40% versus 0% to 9%, respectively; p values were 0.007 to 0.16, depending on the post-RT interval. Conclusions: Radiation therapy causes volume-dependent perfusion defects in approximately 40% of patients within 2 years of RT. These perfusion defects are associated with corresponding wall-motion abnormalities. Additional study is necessary to better define the long-term functional consequences of RT-induced perfusion defects

Defect-mediated magnetism of transition metal doped zinc oxide thin films

Science.gov (United States)

Roberts, Bradley Kirk

Magnetism in transition metal doped wide band-gap materials is of interest to further the fundamental science of materials and future spintronics applications. Large inter-dopant separations require mediation of ferromagnetism by some method; carrier-mediated mechanisms are typically applicable to dilute magnetic semiconductors with low Curie temperatures. Dilute magnetic oxides, commonly with poor conductivity and TC above room temperature, cannot be described within this theory. Recent experiment and theory developments suggest that ferromagnetic exchange in these materials can be mediated by defects. This research includes experimental results justifying and developing this approach. Thin films of Cr doped ZnO (band gap ˜3.3 eV) were deposited with several processing variations to enhance the effects of either 0-dimensional (vacancy, hydrogen-related defect) or two-dimensional defects (surface/interface) and thereby affect magnetism and conductivity. We observe surface magnetism in dielectric thin films of oxygen-saturated ZnO:Cr with spontaneous magnetic moment and conductance dropping approximately exponentially with increasing thickness. Uniform defect concentrations would not result in such magnetic ordering behavior indicating that magnetism is mediated either by surface defects or differing concentrations of point defects near the surface. Polarized neutron reflectivity profiling confirms a magnetically active region of ˜8 nm at the film surface. Hydrogen is notoriously present as a defect and carrier dopant in ZnO, and artificial introduction of hydrogen in dielectric ZnO:Cr films results in varying electronic and magnetic behavior. Free carriers introduced with hydrogen doping are not spin-polarized requiring an alternative explanation for ferromagnetism. We find from positron annihilation spectroscopy measurements that hydrogen doping increases the concentration of an altered VZn-related defect (a preliminary interpretation) throughout the film, which

[Ultrasound scanning of the distraction regenerate in case of multilocus elongation of the fragments in patients with defects of long bones].

Science.gov (United States)

Menshikova, T I; Borzunov, D Iu; Dolganova, T I

2014-01-01

It was done ultrasound examination of distraction regenerates in patients with defect of bone tissue. The first group included 4 patients who had the size of congenital bone tissue defect 15.8±8.1 cm; the second group (3 patients) included posttraumatic defects with defect size 11.75±3.6 cm; the third group (4 patients) included posttraumatic defects with defect size 11±5.3 cm. It was discovered the particularities of distraction regenerate structural condition in case of low level of reparative osteogenesis. In the first group "ischemic" regenerate was characterized by slow formation of bone trabecules. In the second group "ischemic" regenerate had one or two hypo-echogenic cystic-like formations in the intermediate regenerate area. All patients of the third group had organotypic remodeling of the regenerate according to terms of distraction and fixation.

Determination of defect content and defect profile in semiconductor heterostructures

International Nuclear Information System (INIS)

Zubiaga, A; Garcia, J A; Plazaola, F; Zuniga-Perez, J; Munoz-Sanjose, V

2011-01-01

In this article we present an overview of the technique to obtain the defects depth profile and width of a deposited layer and multilayer based on positron annihilation spectroscopy. In particular we apply the method to ZnO and ZnO/ZnCdO layers deposited on sapphire substrates. After introducing some terminology we first calculate the trend that the W/S parameters of the Doppler broadening measurements must follow, both in a qualitative and quantitative way. From this point we extend the results to calculate the width and defect profiles in deposited layer samples.

Determination of defect content and defect profile in semiconductor heterostructures

Energy Technology Data Exchange (ETDEWEB)

Zubiaga, A [Laboratory of Physics, HUT, PO Box 1100, 02015 TKK, Espoo (Finland); Garcia, J A; Plazaola, F [Zientzia eta Teknologia Fakultatea, Euskal Herriko Unbertsitatea, P. K. 644, 48080, Bilbao (Spain); Zuniga-Perez, J; Munoz-Sanjose, V, E-mail: fernando.plazaola@ehu.es [Universitat de Valencia, Departamento de Fisica Aplicada i Electromagnetisme, Dr. Moliner 50, 46100 Burjassot, Valencia (Spain)

2011-01-10

In this article we present an overview of the technique to obtain the defects depth profile and width of a deposited layer and multilayer based on positron annihilation spectroscopy. In particular we apply the method to ZnO and ZnO/ZnCdO layers deposited on sapphire substrates. After introducing some terminology we first calculate the trend that the W/S parameters of the Doppler broadening measurements must follow, both in a qualitative and quantitative way. From this point we extend the results to calculate the width and defect profiles in deposited layer samples.

[BIPADDLED SPLIT PECTORALIS MAJOR MYOCUTANEOUS FLAPS FOR IMMEDIATE RECONSTRUCTION OF ORAL MUCOSAL DEFECTS AND NECK DEFECTS AFTER RESECTION OF RECURRENT ORAL CANCER].

Science.gov (United States)

Chen, Jie; Jiang, Canhua; Li, Ning; Gao, Zhengyang; Chen, Lichun; Wu, Xiaoshan; Chen, Xinqun; Jian, Xinchun

2015-07-01

To investigate the feasibility of the bipaddled split pectoralis major myocutaneous flap for immediate reconstruction of oral mucosal defects and neck defects after resection of recurrent oral cancer. Six patients with oral mucosal defects combined with neck defects after recurrent oral cancer resection were treated with bipaddled split pectoralis major myocutaneous flap between September 2013 and September 2014. There were 5 males and 1 female with an average age of 54.7 years (range, 45-62 years), including 4 cases of recurrent tongue cancer, 1 case of recurrent mandibular gingival cancer, and 1 case of mouth floor carcinoma. All patients underwent local recurrence at 8 to 14 months after first operation, with no distant metastasis. The defects of the intraoral mucosa was 4.0 cm x 2.5 cm to 6.5 cm x 3.5 cm and the defect of the neck skin was 5.5 cm x 3.5 cm to 7.5 cm x 5.0 cm. The pectoralis major myocutaneous flaps (14.0 cm x 3.5 cm to 17.0 cm x 5.5 cm) were incised at the level of the 3rd to the 4th rib, and then split down along the muscle fiber till about 2 cm away from the thoracoacromial vessels, forming 2 independent skin paddles with 1-2 branch vessels to the pedicles of the distal ones. The distal skin paddles were used for oral reconstruction while the proximal paddles for repair of neck defects. The chest donor sites were sutured directly. Cervical haematoma and infection happened in 1 patient respectively after operation, and were cured after symptomatic treatment. All 6 split pectoralis major myocutaneous flaps with 12 skin paddles completely survived. All patients were followed up 6 to 18 months (mean, 11 months). One patient died of pulmonary metastasis at 8 months after operation and the other 5 survived without relapse or metastasis during follow-up. The intraoral paddles showed good shape with satisfactory speech function and swallowing recovery. The paddles also healed perfectly on the neck with flat outlooks, and all patients obtained full

Infrared birefringence imaging of residual stress and bulk defects in multicrystalline silicon

Energy Technology Data Exchange (ETDEWEB)

Ganapati, Vidya; Schoenfelder, Stephan; Castellanos, Sergio; Oener, Sebastian; Koepge, Ringo; Sampson, Aaron; Marcus, Matthew A.; Lai, Barry; Morhenn, Humphrey; Hahn, Giso; Bagdahn, Joerg; Buonassisi1, Tonio

2010-05-05

This manuscript concerns the application of infrared birefringence imaging (IBI) to quantify macroscopic and microscopic internal stresses in multicrystalline silicon (mc-Si) solar cell materials. We review progress to date, and advance four closely related topics. (1) We present a method to decouple macroscopic thermally-induced residual stresses and microscopic bulk defect related stresses. In contrast to previous reports, thermally-induced residual stresses in wafer-sized samples are generally found to be less than 5 MPa, while defect-related stresses can be several times larger. (2) We describe the unique IR birefringence signatures, including stress magnitudes and directions, of common microdefects in mc-Si solar cell materials including: {beta}-SiC and {beta}-Si{sub 3}N{sub 4} microdefects, twin bands, nontwin grain boundaries, and dislocation bands. In certain defects, local stresses up to 40 MPa can be present. (3) We relate observed stresses to other topics of interest in solar cell manufacturing, including transition metal precipitation, wafer mechanical strength, and minority carrier lifetime. (4) We discuss the potential of IBI as a quality-control technique in industrial solar cell manufacturing.

Photoluminescence as a tool for characterizing point defects in semiconductors

Science.gov (United States)

Reshchikov, Michael

2012-02-01

Photoluminescence is one of the most powerful tools used to study optically-active point defects in semiconductors, especially in wide-bandgap materials. Gallium nitride (GaN) and zinc oxide (ZnO) have attracted considerable attention in the last two decades due to their prospects in optoelectronics applications, including blue and ultraviolet light-emitting devices. However, in spite of many years of extensive studies and a great number of publications on photoluminescence from GaN and ZnO, only a few defect-related luminescence bands are reliably identified. Among them are the Zn-related blue band in GaN, Cu-related green band and Li-related orange band in ZnO. Numerous suggestions for the identification of other luminescence bands, such as the yellow band in GaN, or green and yellow bands in ZnO, do not stand up under scrutiny. In these conditions, it is important to classify the defect-related luminescence bands and find their unique characteristics. In this presentation, we will review the origin of the major luminescence bands in GaN and ZnO. Through simulations of the temperature and excitation intensity dependences of photoluminescence and by employing phenomenological models we are able to obtain important characteristics of point defects such as carrier capture cross-sections for defects, concentrations of defects, and their charge states. These models are also used to find the absolute internal quantum efficiency of photoluminescence and obtain information about nonradiative defects. Results from photoluminescence measurements will be compared with results of the first-principle calculations, as well as with the experimental data obtained by other techniques such as positron annihilation spectroscopy, deep-level transient spectroscopy, and secondary ion mass spectrometry.

Additive manufacturing for in situ repair of osteochondral defects

International Nuclear Information System (INIS)

Cohen, Daniel L; Lipton, Jeffrey I; Bonassar, Lawrence J; Lipson, Hod

2010-01-01

Tissue engineering holds great promise for injury repair and replacement of defective body parts. While a number of techniques exist for creating living biological constructs in vitro, none have been demonstrated for in situ repair. Using novel geometric feedback-based approaches and through development of appropriate printing-material combinations, we demonstrate the in situ repair of both chondral and osteochondral defects that mimic naturally occurring pathologies. A calf femur was mounted in a custom jig and held within a robocasting-based additive manufacturing (AM) system. Two defects were induced: one a cartilage-only representation of a grade IV chondral lesion and the other a two-material bone and cartilage fracture of the femoral condyle. Alginate hydrogel was used for the repair of cartilage; a novel formulation of demineralized bone matrix was used for bone repair. Repair prints for both defects had mean surface errors less than 0.1 mm. For the chondral defect, 42.8 ± 2.6% of the surface points had errors that were within a clinically acceptable error range; however, with 1 mm path planning shift, an estimated ∼75% of surface points could likely fall within the benchmark envelope. For the osteochondral defect, 83.6 ± 2.7% of surface points had errors that were within clinically acceptable limits. In addition to implications for minimally invasive AM-based clinical treatments, these proof-of-concept prints are some of the only in situ demonstrations to-date, wherein the substrate geometry was unknown a priori. The work presented herein demonstrates in situ AM, suggests potential biomedical applications and also explores in situ-specific issues, including geometric feedback, material selection and novel path planning techniques.

Defining defect specifications to optimize photomask production and requalification

Science.gov (United States)

Fiekowsky, Peter

2006-10-01

Reducing defect repairs and accelerating defect analysis is becoming more important as the total cost of defect repairs on advanced masks increases. Photomask defect specs based on printability, as measured on AIMS microscopes has been used for years, but the fundamental defect spec is still the defect size, as measured on the photomask, requiring the repair of many unprintable defects. ADAS, the Automated Defect Analysis System from AVI is now available in most advanced mask shops. It makes the use of pure printability specs, or "Optimal Defect Specs" practical. This software uses advanced algorithms to eliminate false defects caused by approximations in the inspection algorithm, classify each defect, simulate each defect and disposition each defect based on its printability and location. This paper defines "optimal defect specs", explains why they are now practical and economic, gives a method of determining them and provides accuracy data.

Metastable and bistable defects in silicon

International Nuclear Information System (INIS)

Mukashev, Bulat N; Abdullin, Kh A; Gorelkinskii, Yurii V

2000-01-01

Existing data on the properties and structure of metastable and bistable defects in silicon are analyzed. Primary radiation-induced defects (vacancies, self-interstitial atoms, and Frenkel pairs), complexes of oxygen, carbon, hydrogen, and other impurity atoms and defects with negative correlation energy are considered. (reviews of topical problems)

Topological defects in extended inflation

International Nuclear Information System (INIS)

Copeland, E.J.; Kolb, E.W.; Chicago Univ., IL; Liddle, A.R.

1990-04-01

We consider the production of topological defects, especially cosmic strings, in extended inflation models. In extended inflation, the Universe passes through a first-order phase transition via bubble percolation, which naturally allows defects to form at the end of inflation. The correlation length, which determines the number density of the defects, is related to the mean size of bubbles when they collide. This mechanism allows a natural combination of inflation and large-scale structure via cosmic strings. 18 refs

Topological defects in extended inflation

International Nuclear Information System (INIS)

Copeland, E.J.; Kolb, E.W.; Liddle, A.R.

1990-01-01

We consider the production of topological defects, especially cosmic strings, in extended-inflation models. In extended inflation, the Universe passes through a first-order phase transition via bubble percolation, which naturally allows defects to form at the end of inflation. The correlation length, which determines the number density of the defects, is related to the mean size of the bubbles when they collide. This mechanism allows a natural combination of inflation and large-scale structure via cosmic strings

Defect accumulation under cascade damage conditions

DEFF Research Database (Denmark)

Trinkaus, H.; Singh, B.N.; Woo, C.H.

1994-01-01

in terms of this reaction kinetics taking into account cluster production, dissociation, migration and annihilation at extended sinks. Microstructural features which are characteristic of cascade damage and cannot be explained in terms of the conventional single defect reaction kinetics are emphasized......There is now ample evidence from both experimental and computer simulation studies that in displacement cascades not only intense recombination takes place but also efficient clustering of both self-interstitial atoms (SIAs) and vacancies. The size distributions of the two types of defects produced...... reactions kinetics associated with the specific features of cascade damage is described, with emphasis on asymmetries between SIA and vacancy type defects concerning their production, stability, mobility and interactions with other defects. Defect accumulation under cascade damage conditions is discussed...

A Baseline-Free Defect Imaging Technique in Plates Using Time Reversal of Lamb Waves

International Nuclear Information System (INIS)

Jeong, Hyunjo; Cho, Sungjong; Wei, Wei

2011-01-01

We present an analytical investigation for a baseline-free imaging of a defect in plate-like structures using the time-reversal of Lamb waves. We first consider the flexural wave (A 0 mode) propagation in a plate containing a defect, and reception and time reversal process of the output signal at the receiver. The received output signal is then composed of two parts: a directly propagated wave and a scattered wave from the defect. The time reversal of these waves recovers the original input signal, and produces two additional sidebands that contain the time-of-flight information on the defect location. One of the side-band signals is then extracted as a pure defect signal. A defect localization image is then constructed from a beamforming technique based on the time-frequency analysis of the side band signal for each transducer pair in a network of sensors. The simulation results show that the proposed scheme enables the accurate, baseline-free imaging of a defect. (fundamental areas of phenomenology(including applications))

Building defects in Danish construction: project characteristics influencing the occurrence of defects at handover

DEFF Research Database (Denmark)

Schultz, Casper Siebken; Jørgensen, Kirsten; Bonke, Sten

2015-01-01

Defects in construction have gained much attention from both the public and academia. Danish construction is no exception and a number of political initiatives have been established to address the unsatisfying amounts of defects. One of the political initiatives, benchmarking, collects and provides...... those with many and/or serious defects. The article reviews the results from studying two quantitative data sets: (I) benchmarking data from 329 building projects and 621 contracts and (II) questionnaire data from an electronic survey comprising 130 contractors. This study provides in-depth knowledge...

Direct Observation of Radiation Defects: Experiment and Interpretation

International Nuclear Information System (INIS)

Dudarev, S.L.

2012-01-01

Electron microscopy is arguably the only available experimental method suitable for the direct visualization of nano-scale defect structures formed under irradiation. Images of dislocation loops and point-defect clusters in crystals are usually produced using diffraction contrast methods. For relatively large defects, a combination of dynamical imaging and image contrast simulations is required for determining the nature of visible radiation defects. At the same time, density functional theory (DFT) models developed over the last decade have provided unique information about the structure of nano-scale defects produced by irradiation, including the defects that are so small that they cannot be observed in an electron microscope, and about the pathways of migration and interaction between radiation defects. DFT models, involving no experimental input parameters and being as quantitatively accurate and informative as the most advanced experimental techniques for the direct observation of defects, have created a new paradigm for the scientific investigation of radiation damage phenomena. In particular, DFT models offer new insight into the origin of temperature-dependent response of materials to irradiation, a problem of pivotal significance for applications. By combining information derived from the first-principles models for radiation defects with information derived from small-scale experimental observations it may be possible to acquire quantitative knowledge about how materials respond to irradiation and, using this knowledge, develop materials suitable for advanced applications in fission and fusion. It now appears possible to pose the question about the development of integrated fusion power plant models, combining neutron transport calculations and microscopic models for microstructural evolution of materials, for example models for ab initio prediction of helium embrittlement. Such models, based on scientific principles and quantitative data, and developed

SCATTERING OF SPIN WAVES BY MAGNETIC DEFECTS

Energy Technology Data Exchange (ETDEWEB)

Callaway, Joseph

1962-12-15

The scattering of spin waves by magnetic point defects is considered using a Green's function method. A partial wave expansion for the scattering amplitude is derived. An expression for the cross section is determined that includes the effect of resonant states. Application is made to the calculation of the thermal conductivity of an insulating ferromagnet. (auth)

Quantum computing with defects

Science.gov (United States)

Varley, Joel

2011-03-01

The development of a quantum computer is contingent upon the identification and design of systems for use as qubits, the basic units of quantum information. One of the most promising candidates consists of a defect in diamond known as the nitrogen-vacancy (NV-1) center, since it is an individually-addressable quantum system that can be initialized, manipulated, and measured with high fidelity at room temperature. While the success of the NV-1 stems from its nature as a localized ``deep-center'' point defect, no systematic effort has been made to identify other defects that might behave in a similar way. We provide guidelines for identifying other defect centers with similar properties. We present a list of physical criteria that these centers and their hosts should meet and explain how these requirements can be used in conjunction with electronic structure theory to intelligently sort through candidate systems. To elucidate these points, we compare electronic structure calculations of the NV-1 center in diamond with those of several deep centers in 4H silicon carbide (SiC). Using hybrid functionals, we report formation energies, configuration-coordinate diagrams, and defect-level diagrams to compare and contrast the properties of these defects. We find that the NC VSi - 1 center in SiC, a structural analog of the NV-1 center in diamond, may be a suitable center with very different optical transition energies. We also discuss how the proposed criteria can be translated into guidelines to discover NV analogs in other tetrahedrally coordinated materials. This work was performed in collaboration with J. R. Weber, W. F. Koehl, B. B. Buckley, A. Janotti, C. G. Van de Walle, and D. D. Awschalom. This work was supported by ARO, AFOSR, and NSF.

Reliability analysis of digital radiography systems in the testing of real material defects

International Nuclear Information System (INIS)

Kanzler, Daniel

2016-01-01

Nondestructive testing (ndt) systems are essential for areas in our lives, in which there is a high risk for failures that would induce high costs or even damage to people and the environment (i.e. transportation, energy production, chemical industry). It is necessary to find and to characterise every defect in the material which might jeopardise the functionality of the tested part. But in the praxis the testing system will be used at their limits, i.e. for detecting small defects. Thus, there is a probability that critical defects might be overseen, which must be quantified. The evaluation is especially important for safety-relevant areas. The probability of detection (POD) characteristic is an objective number, which is widely used in these cases. It is used to provide a statement about the tested ndt system. The POD can provide the statement whether the system is working well enough to be accepted to find the defects. The original POD method was developed for one-dimensional defects in thin parts used in the aircraft industry. In reality, the evaluation is a compromise between statistics and costs. On the one hand, the real testing situation should be evaluated for the later use. On the other hand, the evaluation of real defects including the metallography and the comparison with the signals is a complex and expensive task. To find a coordinate system to compare the data is, therefore, an important prerequisite, before starting to evaluate. Therefore, this thesis will present a practical approach. The research community, as well, sees the POD of the real defects as a challenge. It is necessary to extend the one-parametric POD approach by evaluating the whole NDT indication. The area of the NDT indication is one important fact which should be included. The thesis will introduce two new aspects to the calculation of the POD: 1. The area of the indication will be introduced by using a smoothing algorithm, which is based on the known Observer-POD. The Observer

3D modeling of missing pellet surface defects in BWR fuel

Energy Technology Data Exchange (ETDEWEB)

Spencer, B.W., E-mail: Benjamin.Spencer@inl.gov; Williamson, R.L.; Stafford, D.S.; Novascone, S.R.; Hales, J.D.; Pastore, G.

2016-10-15

Highlights: • A global/local analysis procedure for missing pellet surface defects is proposed. • This is applied to defective BWR fuel under blade withdrawal and high power ramp conditions. • Sensitivity of the cladding response to key model parameters is studied. - Abstract: One of the important roles of cladding in light water reactor fuel rods is to prevent the release of fission products. To that end, it is essential that the cladding maintain its integrity under a variety of thermal and mechanical loading conditions. Local geometric irregularities in fuel pellets caused by manufacturing defects known as missing pellet surfaces (MPS) can in some circumstances lead to elevated cladding stresses that are sufficiently high to cause cladding failure. Accurate modeling of these defects can help prevent these types of failures. The BISON nuclear fuel performance code developed at Idaho National Laboratory can be used to simulate the global thermo-mechanical fuel rod behavior, as well as the local response of regions of interest, in either 2D or 3D. In either case, a full set of models to represent the thermal and mechanical properties of the fuel, cladding and plenum gas is employed. A procedure for coupling 2D full-length fuel rod models to detailed 3D models of the region of the rod containing a MPS defect is detailed here. The global and local model each contain appropriate physics and behavior models for nuclear fuel. This procedure is demonstrated on a simulation of a boiling water reactor (BWR) fuel rod containing a pellet with an MPS defect, subjected to a variety of transient events, including a control blade withdrawal and a ramp to high power. The importance of modeling the local defect using a 3D model is highlighted by comparing 3D and 2D representations of the defective pellet region. Parametric studies demonstrate the effects of the choice of gaseous swelling model and of the depth and geometry of the MPS defect on the response of the cladding

Point defects in hexagonal germanium carbide monolayer: A first-principles calculation

International Nuclear Information System (INIS)

Ersan, Fatih; Gökçe, Aytaç Gürhan; Aktürk, Ethem

2016-01-01

Highlights: • Semiconductor GeC turns into metal by introducing a carbon vacancy. • Semiconductor GeC becomes half-metal by a single Ge vacancy. • Band gap value of GeC system can be tuned in the range of 0.308–1.738 eV by antisite or Stone–Wales defects. - Abstract: On the basis of first-principles plane-wave calculations, we investigated the electronic and magnetic properties of various point defects including single Ge and C vacancies, Ge + C divacancy, Ge↔C antisites and the Stone–Wales (SW) defects in a GeC monolayer. We found that various periodic vacancy defects in GeC single layer give rise to crucial effects on the electronic and magnetic properties. The band gaps of GeC monolayer vary significantly from 0.308 eV to 1.738 eV due to the presence of antisites and Stone–Wales defects. While nonmagnetic ground state of semiconducting GeC turns into metal by introducing a carbon vacancy, it becomes half-metal by a single Ge vacancy with high magnetization (4 μ_B) value per supercell. All the vacancy types have zero net magnetic moments, except single Ge vacancy.

Point defects in hexagonal germanium carbide monolayer: A first-principles calculation

Energy Technology Data Exchange (ETDEWEB)

Ersan, Fatih [Department of Physics, Adnan Menderes University, 09100 Aydın (Turkey); Gökçe, Aytaç Gürhan [Department of Physics, Adnan Menderes University, 09100 Aydın (Turkey); Department of Physics, Dokuz Eylül University, 35160 İzmir (Turkey); Aktürk, Ethem, E-mail: ethem.akturk@adu.edu.tr [Department of Physics, Adnan Menderes University, 09100 Aydın (Turkey); Nanotechnology Application and Research Center, Adnan Menderes University, 09100 Aydın (Turkey)

2016-12-15

Highlights: • Semiconductor GeC turns into metal by introducing a carbon vacancy. • Semiconductor GeC becomes half-metal by a single Ge vacancy. • Band gap value of GeC system can be tuned in the range of 0.308–1.738 eV by antisite or Stone–Wales defects. - Abstract: On the basis of first-principles plane-wave calculations, we investigated the electronic and magnetic properties of various point defects including single Ge and C vacancies, Ge + C divacancy, Ge↔C antisites and the Stone–Wales (SW) defects in a GeC monolayer. We found that various periodic vacancy defects in GeC single layer give rise to crucial effects on the electronic and magnetic properties. The band gaps of GeC monolayer vary significantly from 0.308 eV to 1.738 eV due to the presence of antisites and Stone–Wales defects. While nonmagnetic ground state of semiconducting GeC turns into metal by introducing a carbon vacancy, it becomes half-metal by a single Ge vacancy with high magnetization (4 μ{sub B}) value per supercell. All the vacancy types have zero net magnetic moments, except single Ge vacancy.

Defect identification using positrons

International Nuclear Information System (INIS)

Beling, C.D.; Fung, S.

2001-01-01

The current use of the lifetime and Doppler broadening techniques in defect identification is demonstrated with two studies, the first being the identification of carbon vacancy in n-6H SiC through lifetime spectroscopy, and the second the production of de-hydrogenated voids in α-Si:H through light soaking. Some less conventional ideas are presented for more specific defect identification, namely (i) the amalgamation of lifetime and Doppler techniques with conventional deep level transient spectroscopy in what may be called ''positron-deep level transient spectroscopy'', and (ii) the extraction of more spatial information on vacancy defects by means of what may be called ''Fourier transform Doppler broadening of annihilation radiation spectroscopy'' (orig.)

Integrating image processing and classification technology into automated polarizing film defect inspection

Science.gov (United States)

Kuo, Chung-Feng Jeffrey; Lai, Chun-Yu; Kao, Chih-Hsiang; Chiu, Chin-Hsun

2018-05-01

In order to improve the current manual inspection and classification process for polarizing film on production lines, this study proposes a high precision automated inspection and classification system for polarizing film, which is used for recognition and classification of four common defects: dent, foreign material, bright spot, and scratch. First, the median filter is used to remove the impulse noise in the defect image of polarizing film. The random noise in the background is smoothed by the improved anisotropic diffusion, while the edge detail of the defect region is sharpened. Next, the defect image is transformed by Fourier transform to the frequency domain, combined with a Butterworth high pass filter to sharpen the edge detail of the defect region, and brought back by inverse Fourier transform to the spatial domain to complete the image enhancement process. For image segmentation, the edge of the defect region is found by Canny edge detector, and then the complete defect region is obtained by two-stage morphology processing. For defect classification, the feature values, including maximum gray level, eccentricity, the contrast, and homogeneity of gray level co-occurrence matrix (GLCM) extracted from the images, are used as the input of the radial basis function neural network (RBFNN) and back-propagation neural network (BPNN) classifier, 96 defect images are then used as training samples, and 84 defect images are used as testing samples to validate the classification effect. The result shows that the classification accuracy by using RBFNN is 98.9%. Thus, our proposed system can be used by manufacturing companies for a higher yield rate and lower cost. The processing time of one single image is 2.57 seconds, thus meeting the practical application requirement of an industrial production line.

Influence of point defects on the near edge structure of hexagonal boron nitride

Science.gov (United States)

McDougall, Nicholas L.; Partridge, Jim G.; Nicholls, Rebecca J.; Russo, Salvy P.; McCulloch, Dougal G.

2017-10-01

Hexagonal boron nitride (hBN) is a wide-band-gap semiconductor with applications including gate insulation layers in graphene transistors, far-ultraviolet light emitting devices and as hydrogen storage media. Due to its complex microstructure, defects in hBN are challenging to identify. Here, we combine x-ray absorption near edge structure (XANES) spectroscopy with ab initio theoretical modeling to identify energetically favorable defects. Following annealing of hBN samples in vacuum and oxygen, the B and N K edges exhibited angular-dependent peak modifications consistent with in-plane defects. Theoretical calculations showed that the energetically favorable defects all produce signature features in XANES. Comparing these calculations with experiments, the principle defects were attributed to substitutional oxygen at the nitrogen site, substitutional carbon at the boron site, and hydrogen passivated boron vacancies. Hydrogen passivation of defects was found to significantly affect the formation energies, electronic states, and XANES. In the B K edge, multiple peaks above the major 1 s to π* peak occur as a result of these defects and the hydrogen passivated boron vacancy produces the frequently observed doublet in the 1 s to σ* transition. While the N K edge is less sensitive to defects, features attributable to substitutional C at the B site were observed. This defect was also calculated to have mid-gap states in its band structure that may be responsible for the 4.1-eV ultraviolet emission frequently observed from this material.

Electronic structure of point defects in semiconductors

International Nuclear Information System (INIS)

Bruneval, Fabien

2014-01-01

This 'Habilitation a diriger des Recherches' memoir presents most of my scientific activities during the past 7 years, in the field of electronic structure calculations of defects in solids. Point defects (vacancies, interstitials, impurities) in functional materials are a key parameter to determine if these materials will actually fill the role they have been assigned or not. Indeed, the presence of defects cannot be avoided when the temperature is increased or when the material is subjected to external stresses, such as irradiation in the nuclear reactors and in artificial satellites with solar radiations. However, in many cases, defects are introduced in the materials on purpose to tune the electronic transport, optical or even magnetic properties. This procedure is called the doping of semiconductors, which is the foundation technique for transistors, diodes, or photovoltaic cells. However, doping is not always straightforward and unexpected features may occur, such as doping asymmetry or Fermi level pinning, which can only be explained by complex phenomena involving different types of defects or complexes of defects. In this context, the calculations of electronic structure ab initio is an ideal tool to complement the experimental observations, to gain the understanding of phenomena at the atomic level, and even to predict the properties of defects. The power of the ab initio calculations comes from their ability to describe any system of electrons and nuclei without any specific adjustment. But although there is a strong need for numerical simulations in this field, the ab initio calculations for defects are still under development as of today. The work presented in this memoir summarizes my contributions to methodological developments on this subject. These developments have followed two main tracks. The first topic is the better understanding of the unavoidable finite size effects. Indeed, defects in semiconductors or insulators are generally present in

Point defects and atomic transport in crystals

International Nuclear Information System (INIS)

Lidiard, A.B.

1981-02-01

There are two principle aspects to the theory of atomic transport in crystals as caused by the action of point defects, namely (1) the calculation of relevant properties of the point defects (energies and other thermodynamic characteristics of the different possible defects, activation energies and other mobility parameters) and (2) the statistical mechanics of assemblies of defects, both equilibrium and non-equilibrium assemblies. In the five lectures given here both these aspects are touched on. The first two lectures are concerned with the calculation of relevant point defect properties, particularly in ionic crystals. The first lecture is more general, the second is concerned particularly with some recent calculations of the free volumes of formation of defects in various ionic solids; these solve a rather long-standing problem in this area. The remaining three lectures are concerned with the kinetic theory of defects mainly in relaxation, drift and diffusion situations

Characterization of electrically-active defects in ultraviolet light-emitting diodes with laser-based failure analysis techniques

International Nuclear Information System (INIS)

Miller, Mary A.; Tangyunyong, Paiboon; Cole, Edward I.

2016-01-01

Laser-based failure analysis techniques demonstrate the ability to quickly and non-intrusively screen deep ultraviolet light-emitting diodes (LEDs) for electrically-active defects. In particular, two laser-based techniques, light-induced voltage alteration and thermally-induced voltage alteration, generate applied voltage maps (AVMs) that provide information on electrically-active defect behavior including turn-on bias, density, and spatial location. Here, multiple commercial LEDs were examined and found to have dark defect signals in the AVM indicating a site of reduced resistance or leakage through the diode. The existence of the dark defect signals in the AVM correlates strongly with an increased forward-bias leakage current. This increased leakage is not present in devices without AVM signals. Transmission electron microscopy analysis of a dark defect signal site revealed a dislocation cluster through the pn junction. The cluster included an open core dislocation. Even though LEDs with few dark AVM defect signals did not correlate strongly with power loss, direct association between increased open core dislocation densities and reduced LED device performance has been presented elsewhere [M. W. Moseley et al., J. Appl. Phys. 117, 095301 (2015)

Characterization of electrically-active defects in ultraviolet light-emitting diodes with laser-based failure analysis techniques

Energy Technology Data Exchange (ETDEWEB)

Miller, Mary A.; Tangyunyong, Paiboon; Cole, Edward I. [Sandia National Laboratories, Albuquerque, New Mexico 87185-1086 (United States)

2016-01-14

Laser-based failure analysis techniques demonstrate the ability to quickly and non-intrusively screen deep ultraviolet light-emitting diodes (LEDs) for electrically-active defects. In particular, two laser-based techniques, light-induced voltage alteration and thermally-induced voltage alteration, generate applied voltage maps (AVMs) that provide information on electrically-active defect behavior including turn-on bias, density, and spatial location. Here, multiple commercial LEDs were examined and found to have dark defect signals in the AVM indicating a site of reduced resistance or leakage through the diode. The existence of the dark defect signals in the AVM correlates strongly with an increased forward-bias leakage current. This increased leakage is not present in devices without AVM signals. Transmission electron microscopy analysis of a dark defect signal site revealed a dislocation cluster through the pn junction. The cluster included an open core dislocation. Even though LEDs with few dark AVM defect signals did not correlate strongly with power loss, direct association between increased open core dislocation densities and reduced LED device performance has been presented elsewhere [M. W. Moseley et al., J. Appl. Phys. 117, 095301 (2015)].

Antigravity from a spacetime defect

OpenAIRE

Klinkhamer, F. R.; Queiruga, J. M.

2018-01-01

We argue that there may exist spacetime defects embedded in Minkowski spacetime, which have negative active gravitational mass. One such spacetime defect then repels a test particle, corresponding to what may be called "antigravity."

Sub-surface defect detection using transient thermography

International Nuclear Information System (INIS)

Mohd Zaki Umar; Huda Abdullah; Abdul Razak Hamzah; Wan Saffiey Wan Abdullah; Ibrahim Ahmad; Vavilov, Vladimir

2009-04-01

An experimental research had been carried out to study the potential of transient thermography in detecting sub-surface defect of non-metal material. In this research, eight pieces of bakelite material were used as samples. Each samples had a sub-surface defect in the circular shape with different diameters and depths. Experiment was conducted using one-sided Pulsed Thermal technique. Heating of samples were done using 30 k Watt adjustable quartz lamp while infra red (IR) images of samples were recorded using THV 550 IR camera. These IR images were then analysed with thermo fit TM Pro software to obtain the Maximum Absolute Differential Temperature Signal value, ΔT max and the time of its appearance, τ max (ΔT). Result showed that all defects were able to be detected even for the smallest and deepest defect (diameter = 5 mm and depth = 4 mm). However the highest value of Differential Temperature Signal (ΔT max ), were obtained at defect with the largest diameter, 20 mm and at the shallowest depth, 1 mm. As a conclusion, the sensitivity of the pulsed thermography technique to detect sub-surface defects of bakelite material is proportionately related with the size of defect diameter if the defect area at the same depth. On the contrary, the sensitivity of the pulsed thermography technique inversely related with the depth of defect if the defects have similar diameter size. (author)

How Do We Define Congenital Heart Defects for Scientific Studies?

DEFF Research Database (Denmark)

Garne, Ester; Olsen, Morten Smaerup; Johnsen, Søren Paaske

2012-01-01

of echocardiography in neonatal intensive care, a patent ductus arteriosus (PDA) or flow over the atrial septum will often be visible. These findings may be coded as CHD at discharge and in this way falsely increase the CHD prevalence in the population. There are several purposes for which population-based data...... practice. We include PDA and atrial septal defects as CHD cases if these defects are still open 2 months after birth. International consensus on how to define CHD would improve the validity and comparability of epidemiological studies on CHD....

Mapping genes governing flower architecture and pollen development in a double mutant population of carrot

Directory of Open Access Journals (Sweden)

Holger eBudahn

2014-10-01

Full Text Available A linkage map of carrot (Daucus carota L. was developed in order to study reproductive traits. The F2 mapping population derived from an initial cross between a yellow leaf (yel chlorophyll mutant and a compressed lamina (cola mutant with unique flower defects of the sporophytic parts of male and female organs. The genetic map has a total length of 781 cM and included 285 loci. The length of the nine linkage groups ranged between 65 cM and 145 cM. All linkage groups have been anchored to the reference map. The objective of this study was the generation of a well-saturated linkage map of D. carota. Mapping of the cola-locus associated with flower development and fertility was successfully demonstrated. Two MADS-box genes (DcMADS3, DcMADS5 with prominent roles in flowering and reproduction as well as three additional genes (DcAOX2a, DcAOX2b, DcCHS2 with further importance for male reproduction were assigned to different loci that did not co-segregate with the cola-locus.

Electron irradiation-induced defects in {beta}-SiC

Energy Technology Data Exchange (ETDEWEB)

Oshima, Ryuichiro [Osaka Prefectural Univ., Sakai (Japan). Reseach Inst. for Advanced Science and Technology

1996-04-01

To add information of point defects in cubic crystal SiC, polycrystal {beta}-SiC on the market was used as sample and irradiated by neutron and electron. In situ observation of neutron and electron irradiation-induced defects in {beta}-SiC were carried out by ultra high-voltage electronic microscope (UHVEM) and ordinary electronic microscope. The obtained results show that the electron irradiation-induced secondary defects are micro defects less than 20 nm at about 1273K, the density of defects is from 2x10{sup 17} to 1x10{sup 18}/cc, the secondary defects may be hole type at high temperature and the preexistant defects control nuclear formation of irradiation-induced defects, effective sink. (S.Y.)

48 CFR 52.215-10 - Price Reduction for Defective Certified Cost or Pricing Data.

Science.gov (United States)

2010-10-01

... Defective Certified Cost or Pricing Data. 52.215-10 Section 52.215-10 Federal Acquisition Regulations System... Text of Provisions and Clauses 52.215-10 Price Reduction for Defective Certified Cost or Pricing Data... or Pricing Data (OCT 2010) (a) If any price, including profit or fee, negotiated in connection with...

Proteomic approach to characterize biochemistry of meat quality defects.

Science.gov (United States)

Schilling, M W; Suman, S P; Zhang, X; Nair, M N; Desai, M A; Cai, K; Ciaramella, M A; Allen, P J

2017-10-01

Proteomics can be used to characterize quality defects including pale, soft, and exudative (PSE) meat (pork and poultry), woody broiler breast meat, reddish catfish fillets, meat toughness, and beef myoglobin oxidation. PSE broiler meat was characterized by 15 proteins that differed in abundance in comparison to normal broiler breast meat, and eight proteins were differentially expressed in woody breast meat in comparison to normal breast meat. Hemoglobin was the only protein that was differentially expressed between red and normal catfish fillets. However, inducing low oxygen and/or heat stress conditions to catfish fillets did not lead to the production of red fillets. Proteomic data provided information pertaining to the protein differences that exist in meat quality defects. However, these data need to be evaluated in conjunction with information pertaining to genetics, nutrition, environment of the live animal, muscle to meat conversion, meat quality analyses and sensory attributes to understand causality, protein biomarkers, and ultimately how to prevent quality defects. Copyright © 2017 Elsevier Ltd. All rights reserved.

Reconstruction for Skull Base Defect Using Fat-Containing Perifascial Areolar Tissue.

Science.gov (United States)

Choi, Woo Young; Sung, Ki Wook; Kim, Young Seok; Hong, Jong Won; Roh, Tai Suk; Lew, Dae Hyun; Chang, Jong Hee; Lee, Kyu Sung

2017-06-01

Skull base reconstruction is a challenging task. The method depends on the anatomical complexity and size of the defect. We obtained tissue by harvesting fat-containing perifascial areolar tissue (PAT) for reconstruction of limited skull base defects and volume augmentation. We demonstrated the effective option for reconstruction of limited skull base defects and volume augmentation. From October 2013 to November 2015, 5 patients underwent operations using fat-containing PAT to fill the defect in skull base and/or perform volume replacement in the forehead. Perifascial areolar tissue with 5- to 10-mm fat thickness was harvested from the inguinal region. The fat-containing PAT was grafted to the defect contacting the vascularized wound bed. Patients were followed up in terms of their clinical symptoms and postoperative magnetic resonance imaging findings. Four patients were treated using fat-containing PAT after tumor resection. One patient was treated for a posttraumatic forehead depression deformity. The fat-containing PAT included 5- to 9-mm fat thickness in all cases. The mean size of grafted PAT was 65.6 cm (28-140 cm). The mean follow-up period was 18.6 months (12-31 months). There was no notable complication. There was no donor site morbidity. We can harvest PAT with fat easily and obtain the sufficient volume to treat the defect. It also could be used with other reconstructive method, such as a free flap or a regional flap to fill the left dead space. Therefore, fat-containing PAT could be additional options to reconstruction of skull base defect.

Betaine supplementation reduces congenital defects after prenatal alcohol exposure (Conference Presentation)

Science.gov (United States)

Karunamuni, Ganga; Gu, Shi; Doughman, Yong Qiu; Sheehan, Megan M.; Ma, Pei; Peterson, Lindsy M.; Linask, Kersti K.; Jenkins, Michael W.; Rollins, Andrew M.; Watanabe, Michiko

2016-03-01

Over 500,000 women per year in the United States drink during pregnancy, and 1 in 5 of this population also binge drink. As high as 20-50% of live-born children with prenatal alcohol exposure (PAE) present with congenital heart defects including outflow and valvuloseptal anomalies that can be life-threatening. Previously we established a model of PAE (modeling a single binge drinking episode) in the avian embryo and used optical coherence tomography (OCT) imaging to assay early-stage cardiac function/structure and late-stage cardiac defects. At early stages, alcohol/ethanol-exposed embryos had smaller cardiac cushions and increased retrograde flow. At late stages, they presented with gross morphological defects in the head and chest wall, and also exhibited smaller or abnormal atrio-ventricular (AV) valves, thinner interventricular septae (IVS), and smaller vessel diameters for the aortic trunk branches. In other animal models, the methyl donor betaine (found naturally in many foods such as wheat bran, quinoa, beets and spinach) ameliorates neurobehavioral deficits associated with PAE but the effects on heart structure are unknown. In our model of PAE, betaine supplementation led to a reduction in gross structural defects and appeared to protect against certain types of cardiac defects such as ventricular septal defects and abnormal AV valvular morphology. Furthermore, vessel diameters, IVS thicknesses and mural AV leaflet volumes were normalized while the septal AV leaflet volume was increased. These findings highlight the importance of betaine and potentially methylation levels in the prevention of PAE-related birth defects which could have significant implications for public health.

Exploring atomic defects in molybdenum disulphide monolayers

KAUST Repository

Hong, Jinhua; Hu, Zhixin; Probert, Matt; Li, Kun; Lv, Danhui; Yang, Xinan; Gu, Lin; Mao, Nannan; Feng, Qingliang; Xie, Liming; Zhang, Jin; Wu, Dianzhong; Zhang, Zhiyong; Jin, Chuanhong; Ji, Wei; Zhang, Xixiang; Yuan, Jun; Zhang, Ze

2015-01-01

Defects usually play an important role in tailoring various properties of two-dimensional materials. Defects in two-dimensional monolayer molybdenum disulphide may be responsible for large variation of electric and optical properties. Here we present a comprehensive joint experiment-theory investigation of point defects in monolayer molybdenum disulphide prepared by mechanical exfoliation, physical and chemical vapour deposition. Defect species are systematically identified and their concentrations determined by aberration-corrected scanning transmission electron microscopy, and also studied by ab-initio calculation. Defect density up to 3.5 × 10 13 cm '2 is found and the dominant category of defects changes from sulphur vacancy in mechanical exfoliation and chemical vapour deposition samples to molybdenum antisite in physical vapour deposition samples. Influence of defects on electronic structure and charge-carrier mobility are predicted by calculation and observed by electric transport measurement. In light of these results, the growth of ultra-high-quality monolayer molybdenum disulphide appears a primary task for the community pursuing high-performance electronic devices.

Areva solutions for management of defective fuel

International Nuclear Information System (INIS)

Morlaes, I.; Vo Van, V.

2014-01-01

Defective fuel management is a major challenge for nuclear operators when all fuel must be long-term managed. This paper describes AREVA solutions for managing defective fuel. Transport AREVA performs shipments of defective fuel in Europe and proposes casks that are licensed for that purpose in Europe and in the USA. The paper presents the transport experience and the new European licensing approach of defective fuel transport. Dry Interim Storage AREVA is implementing the defective fuel storage in the USA, compliant with the Safety Authority's requirements. In Europe, AREVA is developing a new, more long-term oriented storage solution for defective fuel, the best available technology regarding safety requirements. The paper describes these storage solutions. Treatment Various types of defective fuel coming from around the world have been treated in the AREVA La Hague plant. Specific treatment procedures were developed when needed. The paper presents operational elements related to this experience. (authors)

Exploring atomic defects in molybdenum disulphide monolayers

KAUST Repository

Hong, Jinhua

2015-02-19

Defects usually play an important role in tailoring various properties of two-dimensional materials. Defects in two-dimensional monolayer molybdenum disulphide may be responsible for large variation of electric and optical properties. Here we present a comprehensive joint experiment-theory investigation of point defects in monolayer molybdenum disulphide prepared by mechanical exfoliation, physical and chemical vapour deposition. Defect species are systematically identified and their concentrations determined by aberration-corrected scanning transmission electron microscopy, and also studied by ab-initio calculation. Defect density up to 3.5 × 10 13 cm \\'2 is found and the dominant category of defects changes from sulphur vacancy in mechanical exfoliation and chemical vapour deposition samples to molybdenum antisite in physical vapour deposition samples. Influence of defects on electronic structure and charge-carrier mobility are predicted by calculation and observed by electric transport measurement. In light of these results, the growth of ultra-high-quality monolayer molybdenum disulphide appears a primary task for the community pursuing high-performance electronic devices.

Defect-impurity interactions in ion-implanted metals

International Nuclear Information System (INIS)

Turos, A.

1986-01-01

An overview of defect-impurity interactions in metals is presented. When point defects become mobile they migrate towards the sinks and on the way can be captured by impurity atoms forming stable associations so-called complexes. In some metallic systems complexes can also be formed athermally during ion implantation by trapping point defects already in the collision cascade. An association of a point defect with an impurity atom leads to its displacement from the lattice site. The structure and stability of complexes are strongly temperature dependent. With increasing temperature they dissociate or grow by multiple defect trapping. The appearance of freely migrating point defects at elevated temperatures, due to ion bombardment or thermal annealing, causes via coupling with defect fluxes, important impurity redistribution. Because of the sensitivity of many metal-in-metal implanted systems to radiation damage the understanding of this processes is essential for a proper interpretation of the lattice occupancy measurements and the optimization of implantation conditions. (author)

Birth prevalence of neural tube defects and orofacial clefts in India: a systematic review and meta-analysis.

Directory of Open Access Journals (Sweden)

Komal Preet Allagh

Full Text Available In the last two decades, India has witnessed a substantial decrease in infant mortality attributed to infectious disease and malnutrition. However, the mortality attributed to birth defects remains constant. Studies on the prevalence of birth defects such as neural tube defects and orofacial clefts in India have reported inconsistent results. Therefore, we conducted a systematic review of observational studies to document the birth prevalence of neural tube defects and orofacial clefts.A comprehensive literature search for observational studies was conducted in MEDLINE and EMBASE databases using key MeSH terms (neural tube defects OR cleft lip OR cleft palate AND Prevalence AND India. Two reviewers independently reviewed the retrieved studies, and studies satisfying the eligibility were included. The quality of included studies was assessed using selected criteria from STROBE statement.The overall pooled birth prevalence (random effect of neural tube defects in India is 4.5 per 1000 total births (95% CI 4.2 to 4.9. The overall pooled birth prevalence (random effect of orofacial clefts is 1.3 per 1000 total births (95% CI 1.1 to 1.5. Subgroup analyses were performed by region, time period, consanguinity, and gender of newborn.The overall prevalence of neural tube defects from India is high compared to other regions of the world, while that of orofacial clefts is similar to other countries. The majority of studies included in the review were hospital based. The quality of these studies ranged from low to moderate. Further well-designed, high quality community-based observational studies are needed to accurately estimate the burden of neural tube defects and orofacial clefts in India.

Congenital Heart Defects (For Parents)

Science.gov (United States)

... to be associated with genetic disorders, such as Down syndrome . But the cause of most congenital heart defects isn't known. While they can't be prevented, many treatments are available for the defects and related health ...

Superficial temporal artery flap for reconstruction of complex facial defects: A new algorithm

Directory of Open Access Journals (Sweden)

Tarek M. Elbanoby

2018-03-01

Full Text Available Background A variety of island flaps can be based on the superficial temporal artery with variable tissue composition. They can be used for defect reconstruction, cavity resurfacing, facial hair restoration, or contracture release. Methods Seventy-two patients underwent facial reconstruction using a superficial temporal artery island flap from October 2010 to October 2014. The defects had various etiologies, including trauma, burns, tumors, exposed hardware, and congenital causes. We classified the patients by indication into 5 groups: cavity resurfacing, contracture release, facial hair restoration, skin coverage, and combined. The demographic data of the patients, defect characteristics, operative procedures, postoperative results, and complications were retrospectively documented. The follow-up period ranged from 24 to 54 months. Results A total of 24 females and 48 males were included in this study. The mean age of the patients was 33.7±15.6 years. The flaps were used for contracture release in 13 cases, cavity resurfacing in 10 cases, skin coverage in 17 cases, facial hair restoration in 19 cases, and combined defects in 13 cases. No major complications were reported. Conclusion: Based on our experiences with the use of superficial temporal artery island flaps, we have developed a detailed approach for the optimal management of patients with composite facial defects. The aim of this article is to provide the reader with a systematic algorithm to use for such patients.

Momentum conserving defects in affine Toda field theories

Energy Technology Data Exchange (ETDEWEB)

Bristow, Rebecca; Bowcock, Peter [Department of Mathematical Sciences, Durham University,Durham, DH1 3LE (United Kingdom)

2017-05-30

Type II integrable defects with more than one degree of freedom at the defect are investigated. A condition on the form of the Lagrangian for such defects is found which ensures the existence of a conserved momentum in the presence of the defect. In addition it is shown that for any Lagrangian satisfying this condition, the defect equations of motion, when taken to hold everywhere, can be extended to give a Bäcklund transformation between the bulk theories on either side of the defect. This strongly suggests that such systems are integrable. Momentum conserving defects and Bäcklund transformations for affine Toda field theories based on the A{sub n}, B{sub n}, C{sub n} and D{sub n} series of Lie algebras are found. The defect associated with the D{sub 4} affine Toda field theory is examined in more detail. In particular classical time delays for solitons passing through the defect are calculated.

Porosity Defect Remodeling and Tensile Analysis of Cast Steel

Directory of Open Access Journals (Sweden)

Linfeng Sun

2016-02-01

Full Text Available Tensile properties on ASTM A216 WCB cast steel with centerline porosity defect were studied with radiographic mapping and finite element remodeling technique. Non-linear elastic and plastic behaviors dependent on porosity were mathematically described by relevant equation sets. According to the ASTM E8 tensile test standard, matrix and defect specimens were machined into two categories by two types of height. After applying radiographic inspection, defect morphologies were mapped to the mid-sections of the finite element models and the porosity fraction fields had been generated with interpolation method. ABAQUS input parameters were confirmed by trial simulations to the matrix specimen and comparison with experimental outcomes. Fine agreements of the result curves between simulations and experiments could be observed, and predicted positions of the tensile fracture were found to be in accordance with the tests. Chord modulus was used to obtain the equivalent elastic stiffness because of the non-linear features. The results showed that elongation was the most influenced term to the defect cast steel, compared with elastic stiffness and yield stress. Additional visual explanations on the tensile fracture caused by void propagation were also given by the result contours at different mechanical stages, including distributions of Mises stress and plastic strain.

Topological defects in confined populations of spindle-shaped cells

Science.gov (United States)

Duclos, Guillaume; Erlenkämper, Christoph; Joanny, Jean-François; Silberzan, Pascal

2017-01-01

Most spindle-shaped cells (including smooth muscles and sarcomas) organize in vivo into well-aligned `nematic’ domains, creating intrinsic topological defects that may be used to probe the behaviour of these active nematic systems. Active non-cellular nematics have been shown to be dominated by activity, yielding complex chaotic flows. However, the regime in which live spindle-shaped cells operate, and the importance of cell-substrate friction in particular, remains largely unexplored. Using in vitro experiments, we show that these active cellular nematics operate in a regime in which activity is effectively damped by friction, and that the interaction between defects is controlled by the system’s elastic nematic energy. Due to the activity of the cells, these defects behave as self-propelled particles and pairwise annihilate until all displacements freeze as cell crowding increases. When confined in mesoscopic circular domains, the system evolves towards two identical +1/2 disclinations facing each other. The most likely reduced positions of these defects are independent of the size of the disk, the cells’ activity or even the cell type, but are well described by equilibrium liquid crystal theory. These cell-based systems thus operate in a regime more stable than other active nematics, which may be necessary for their biological function.

Dual approaches for defects condensation

Energy Technology Data Exchange (ETDEWEB)

Rougemont, Romulo; Grigorio, Leonardo de Souza; Wotzasek, Clovis [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil); Guimaraes, Marcelo Santos [Universidade do Estado do Rio de Janeiro (UERJ), RJ (Brazil)

2009-07-01

Full text. Due to the fact that the QCD running coupling constant becomes larger as we go into the low energy (or large distance) limit of the theory, a perturbative treatment of its infrared (IR) region is impossible. In particular, a formal mathematical demonstration of color confinement and a complete physical understanding of the exact mechanism that confines quarks and gluons are two missing points in our current knowledge of the IR-QCD. It was known that due to the Meissner effect of expulsion of magnetic fields in a electric condensate that usual superconductors should confine magnetic monopoles. That point led to the conjecture that the QCD vacuum could be a condensate of chromomagnetic monopoles, a dual superconductor (DSC). Such a chromomagnetic condensate should be responsible for the dual Meissner effect which is expected to lead to the confinement of color charges immersed in this medium. In dual superconductor models of color confinement, magnetic monopoles appear as topological defects in points of the space where the abelian projection becomes singular. Also, condensation of other kinds of defects such as vortices in superfluids and line-like defects in solids are responsible for a great variety of phase transitions, which once more proves the relevance of the subject. In the present work we review two methods that allow us to approach the condensation of defects: the Kleinert Mechanism (KM) and the Julia-Toulouse Mechanism (JTM). We show that in the limit where the vortex gauge field goes to zero, which we identify as the signature of the condensation of defects in the dual picture, these are two equivalent dual prescriptions for obtaining an effective theory for a phase where defects are condensed, starting from the fundamental theory defined in the normal phase where defects are diluted. (author)

Defects in conformal field theory

International Nuclear Information System (INIS)

Billò, Marco; Gonçalves, Vasco; Lauria, Edoardo; Meineri, Marco

2016-01-01

We discuss consequences of the breaking of conformal symmetry by a flat or spherical extended operator. We adapt the embedding formalism to the study of correlation functions of symmetric traceless tensors in the presence of the defect. Two-point functions of a bulk and a defect primary are fixed by conformal invariance up to a set of OPE coefficients, and we identify the allowed tensor structures. A correlator of two bulk primaries depends on two cross-ratios, and we study its conformal block decomposition in the case of external scalars. The Casimir equation in the defect channel reduces to a hypergeometric equation, while the bulk channel blocks are recursively determined in the light-cone limit. In the special case of a defect of codimension two, we map the Casimir equation in the bulk channel to the one of a four-point function without defect. Finally, we analyze the contact terms of the stress-tensor with the extended operator, and we deduce constraints on the CFT data. In two dimensions, we relate the displacement operator, which appears among the contact terms, to the reflection coefficient of a conformal interface, and we find unitarity bounds for the latter.

Defects in conformal field theory

Energy Technology Data Exchange (ETDEWEB)

Billò, Marco [Dipartimento di Fisica, Università di Torino, and Istituto Nazionale di Fisica Nucleare - sezione di Torino,Via P. Giuria 1 I-10125 Torino (Italy); Gonçalves, Vasco [Centro de Física do Porto,Departamento de Física e Astronomia Faculdade de Ciências da Universidade do Porto, Rua do Campo Alegre 687, 4169-007 Porto (Portugal); ICTP South American Institute for Fundamental Research Instituto de Física Teórica,UNESP - University Estadual Paulista,Rua Dr. Bento T. Ferraz 271, 01140-070, São Paulo, SP (Brazil); Lauria, Edoardo [Institute for Theoretical Physics, KU Leuven, Celestijnenlaan 200D, B-3001 Leuven (Belgium); Meineri, Marco [Perimeter Institute for Theoretical Physics,Waterloo, Ontario, N2L 2Y5 (Canada); Scuola Normale Superiore, and Istituto Nazionale di Fisica Nucleare - sezione di Pisa,Piazza dei Cavalieri 7 I-56126 Pisa (Italy)

2016-04-15

We discuss consequences of the breaking of conformal symmetry by a flat or spherical extended operator. We adapt the embedding formalism to the study of correlation functions of symmetric traceless tensors in the presence of the defect. Two-point functions of a bulk and a defect primary are fixed by conformal invariance up to a set of OPE coefficients, and we identify the allowed tensor structures. A correlator of two bulk primaries depends on two cross-ratios, and we study its conformal block decomposition in the case of external scalars. The Casimir equation in the defect channel reduces to a hypergeometric equation, while the bulk channel blocks are recursively determined in the light-cone limit. In the special case of a defect of codimension two, we map the Casimir equation in the bulk channel to the one of a four-point function without defect. Finally, we analyze the contact terms of the stress-tensor with the extended operator, and we deduce constraints on the CFT data. In two dimensions, we relate the displacement operator, which appears among the contact terms, to the reflection coefficient of a conformal interface, and we find unitarity bounds for the latter.

Diagnosis of fetal neural tube defects by MRI

International Nuclear Information System (INIS)

Dong Suzhen; Zhu Ming; Zhong Yumin; Zhang Hong; Pan Huihong

2010-01-01

Objective: To explore the diagnostic value of MRI on fetal neural tube defects. Methods: Ten pregnant women, aged from 25 to 35 years (average 28 years) and with gestation from 20-39 weeks (average 33 weeks) were studied with a 1.5 T superconductive MR unit within 24 to 48 hours after ultrasound (US) studies. The imaging protocol included fast-imaging employing steady-state acquisition, single-shot FSE and T 1 -weighted fast inversion recovery motion insensitive sequences in the axial, fromtal, and sagittal planes relative to the fetal brain, thorax, abdomen, and spines. Prenatal US and MRI findings were compared with postnatal MRI diagnoses (3 fetuses) or autopsy (7 fetuses). Results: Ten pregnant women (9 with a single fetus and 1 with twin fetuses) were examined. For all cases, the diagnoses established by MRI were correct when compared with postnatal diagnosis or autopsy. In 7 cases, US and MRI findings were in complete agreement with postnatal diagnoses. US missed the diagnosis in 1 cases and misdiagnosed in 2 cases. Ten neural tube defects in this study included anencephaly (1 case), exencephaly (1 case), meningoencephalocele associated with amniotic band sequence (1 case), meningocele (1 case), thoracic myelomeningocele (1 case), lumbar spinal bifida (1 case), sacroiliac myelomeningocele (2 cases), sacroiliac large cystic spinal meningocele (1 case), sacroiliac spinal bifida (1 case). Conclusions: Prenatal MRI is effective in the assessment of fetal neural tube defects. It can exactly discriminate herniated contents and locate the spinal lesion level. (authors)

Racial/ethnic variations in the prevalence of selected major birth defects, metropolitan Atlanta, 1994-2005.

Science.gov (United States)

Kucik, James E; Alverson, Clinton J; Gilboa, Suzanne M; Correa, Adolfo

2012-01-01

Birth defects are the leading cause of infant mortality and are responsible for substantial child and adult morbidity. Documenting the variation in prevalence of birth defects among racial/ethnic subpopulations is critical for assessing possible variations in diagnosis, case ascertainment, or risk factors among such groups. We used data from the Metropolitan Atlanta Congenital Defects Program, a population-based birth defects registry with active case ascertainment. We estimated the racial/ethnic variation in prevalence of 46 selected major birth defects among live births, stillbirths, and pregnancy terminations at >20 weeks gestation among mothers residing in the five central counties of metropolitan Atlanta between 1994 and 2005, adjusting for infant sex, maternal age, gravidity, and socioeconomic status (SES). We also explored SES as a potential effect measure modifier. Compared with births to non-Hispanic white women, births to non-Hispanic black women had a significantly higher prevalence of five birth defects and a significantly lower prevalence of 10 birth defects, while births to Hispanic women had a significantly higher prevalence of four birth defects and a significantly lower prevalence of six birth defects. The racial/ethnic disparities in the prevalence of some defects varied by SES, but no clear pattern emerged. Racial/ethnic disparities were suggested in 57% of included birth defects. Disparities in the prevalence of birth defects may result from different underlying genetic susceptibilities; exposure to risk factors; or variability in case diagnosis, ascertainment, or reporting among the subpopulations examined. Policies that improve early diagnosis of birth defects could reduce associated morbidity and mortality.

Concurrence of metaphyseal fibrous defect and osteosarcoma

International Nuclear Information System (INIS)

Kyriakos, M.; Murphy, W.A.

1981-01-01

The case of a 15-year-old girl with juxtaposition of a femoral metaphyseal fibrous defect (fibrous cortical defect) and an osteosarcoma is reported. Despite the relatively common occurrence of metaphyseal fibrous defects, their reported association with other bone tumors is exceedingly rare. Only two previous acceptable examples of this association were found. Reports of malignant transformation of metaphyseal fibrous defect were reviewed and rejected because they lacked convincing radiologic or histopathologic evidence of a pre-existent benign fibrous lesion. The finding of a malignant bone tumor in association with a metaphyseal fibrous defect appears to be a chance occurrence. (orig.)

Extrusion product defects: a statistical study

International Nuclear Information System (INIS)

Qamar, S.Z.; Arif, A.F.M.; Sheikh, A.K.

2003-01-01

In any manufacturing environment, defects resulting in rework or rejection are directly related to product cost and quality, and indirectly linked with process, tooling and product design. An analysis of product defects is therefore integral to any attempt at improving productivity, efficiency and quality. Commercial aluminum extrusion is generally a hot working process and consists of a series of different but integrated operations: billet preheating and sizing, die set and container preheating, billet loading and deformation, product sizing and stretching/roll-correction, age hardening, and painting/anodizing. Product defects can be traced back to problems in billet material and preparation, die and die set design and maintenance, process variable aberrations (ram speed, extrusion pressure, container temperature, etc), and post-extrusion treatment (age hardening, painting/anodizing, etc). The current paper attempts to analyze statistically the product defects commonly encountered in a commercial hot aluminum extrusion setup. Real-world rejection data, covering a period of nine years, has been researched and collected from a local structural aluminum extrusion facility. Rejection probabilities have been calculated for all the defects studied. The nine-year rejection data have been statistically analyzed on the basis of (i) an overall breakdown of defects, (ii) year-wise rejection behavior, (iii) breakdown of defects in each of three cost centers: press, anodizing, and painting. (author)

The reverse sural artery fasciomusculocutaneous flap for small lower-limb defects: the use of the gastrocnemius muscle cuff as a plug for small bony defects following debridement of infected/necrotic bone.

Science.gov (United States)

Al-Qattan, M M

2007-09-01

The reverse sural artery fasciomusculocutaneous flap is a modification of the original fasciocutaneous flap in which a midline gastrocnemius muscle cuff around the buried sural pedicle is included in the flap. This modification was done to improve the blood supply of the distal part of the flap, which is harvested from the upper leg. The aim of this paper is to demonstrate that there is another important advantage of the modified flap: the use of the muscle cuff as a "plug" for small lower limb defects following debridement of infected/necrotic bone. A total of 10 male adult patients with small complex lower-limb defects with underlying bone pathology were treated with the modified flap using the muscle component to fill up the small bony defects. The bony pathology included necrotic exposed bone without evidence of osteomyelitis or wound infection (n = 1), an underlying neglected tibial fracture with wound infection (n = 4), and a sinus at the heel with underlying calcaneal osteomyelitis (n = 5). Primary wound healing of the flap into the defect was noted in all patients. No recurrence of calcaneal osteomyelitis was seen and all tibial fractures united following appropriate orthopedic fixation. It was concluded that the reverse sural artery fasciomusculocutaneous flap is well suited for small complex lower-limb defects with underlying bone pathology.

Defect detection and classification of machined surfaces under multiple illuminant directions

Science.gov (United States)

Liao, Yi; Weng, Xin; Swonger, C. W.; Ni, Jun

2010-08-01

Continuous improvement of product quality is crucial to the successful and competitive automotive manufacturing industry in the 21st century. The presence of surface porosity located on flat machined surfaces such as cylinder heads/blocks and transmission cases may allow leaks of coolant, oil, or combustion gas between critical mating surfaces, thus causing damage to the engine or transmission. Therefore 100% inline inspection plays an important role for improving product quality. Although the techniques of image processing and machine vision have been applied to machined surface inspection and well improved in the past 20 years, in today's automotive industry, surface porosity inspection is still done by skilled humans, which is costly, tedious, time consuming and not capable of reliably detecting small defects. In our study, an automated defect detection and classification system for flat machined surfaces has been designed and constructed. In this paper, the importance of the illuminant direction in a machine vision system was first emphasized and then the surface defect inspection system under multiple directional illuminations was designed and constructed. After that, image processing algorithms were developed to realize 5 types of 2D or 3D surface defects (pore, 2D blemish, residue dirt, scratch, and gouge) detection and classification. The steps of image processing include: (1) image acquisition and contrast enhancement (2) defect segmentation and feature extraction (3) defect classification. An artificial machined surface and an actual automotive part: cylinder head surface were tested and, as a result, microscopic surface defects can be accurately detected and assigned to a surface defect class. The cycle time of this system can be sufficiently fast that implementation of 100% inline inspection is feasible. The field of view of this system is 150mm×225mm and the surfaces larger than the field of view can be stitched together in software.

Reverse Abdominoplasty Flap in Reconstruction of Post-Bilateral Mastectomies Anterior Chest Wall Defect

Directory of Open Access Journals (Sweden)

William HC Tiong

2014-01-01

Full Text Available Reverse abdominoplasty was originally described for epigastric lift. Since the work by Baroudi and Huger in the 1970s, it has become clear that reverse abdominoplasty application can be extended beyond just aesthetic procedure. Through the knowledge of anterior abdominal wall vascularity, its application had included reconstructive prospect in the coverage of various chest wall defects. To date, reverse abdominoplasty flap has been used to reconstruct unilateral anterior chest wall defect or for larger defect but only in combination with other reconstructive techniques. Here, we presented a case where it is used as a standalone flap to reconstruct bilateral anterior chest wall soft tissue defect post-bilateral mastectomies in oncological resection. In conclusion, reverse abdominoplasty flap provided us with a simple, faster, and satisfactory reconstructive outcome.

Automatic classification of defects in weld pipe

International Nuclear Information System (INIS)

Anuar Mikdad Muad; Mohd Ashhar Hj Khalid; Abdul Aziz Mohamad; Abu Bakar Mhd Ghazali; Abdul Razak Hamzah

2000-01-01

With the advancement of computer imaging technology, the image on hard radiographic film can be digitized and stored in a computer and the manual process of defect recognition and classification may be replace by the computer. In this paper a computerized method for automatic detection and classification of common defects in film radiography of weld pipe is described. The detection and classification processes consist of automatic selection of interest area on the image and then classify common defects using image processing and special algorithms. Analysis of the attributes of each defect such as area, size, shape and orientation are carried out by the feature analysis process. These attributes reveal the type of each defect. These methods of defect classification result in high success rate. Our experience showed that sharp film images produced better results

Primordial inhomogeneities from massive defects during inflation

Energy Technology Data Exchange (ETDEWEB)

Firouzjahi, Hassan; Karami, Asieh; Rostami, Tahereh, E-mail: firouz@ipm.ir, E-mail: karami@ipm.ir, E-mail: t.rostami@ipm.ir [School of Astronomy, Institute for Research in Fundamental Sciences (IPM), P.O. Box 19395-5531, Tehran (Iran, Islamic Republic of)

2016-10-01

We consider the imprints of local massive defects, such as a black hole or a massive monopole, during inflation. The massive defect breaks the background homogeneity. We consider the limit that the physical Schwarzschild radius of the defect is much smaller than the inflationary Hubble radius so a perturbative analysis is allowed. The inhomogeneities induced in scalar and gravitational wave power spectrum are calculated. We obtain the amplitudes of dipole, quadrupole and octupole anisotropies in curvature perturbation power spectrum and identify the relative configuration of the defect to CMB sphere in which large observable dipole asymmetry can be generated. We observe a curious reflection symmetry in which the configuration where the defect is inside the CMB comoving sphere has the same inhomogeneous variance as its mirror configuration where the defect is outside the CMB sphere.

Automatic classification of defects in weld pipe

International Nuclear Information System (INIS)

Anuar Mikdad Muad; Mohd Ashhar Khalid; Abdul Aziz Mohamad; Abu Bakar Mhd Ghazali; Abdul Razak Hamzah

2001-01-01

With the advancement of computer imaging technology, the image on hard radiographic film can be digitized and stored in a computer and the manual process of defect recognition and classification may be replaced by the computer. In this paper, a computerized method for automatic detection and classification of common defects in film radiography of weld pipe is described. The detection and classification processes consist of automatic selection of interest area on the image and then classify common defects using image processing and special algorithms. Analysis of the attributes of each defect such area, size, shape and orientation are carried out by the feature analysis process. These attributes reveal the type of each defect. These methods of defect classification result in high success rate. Our experience showed that sharp film images produced better results. (Author)

Scanning Laser Polarimetry and Optical Coherence Tomography for Detection of Retinal Nerve Fiber Layer Defects

Science.gov (United States)

Oh, Jong-Hyun

2009-01-01

Purpose To compare the ability of scanning laser polarimetry with variable corneal compensation (GDx-VCC) and Stratus optical coherence tomography (OCT) to detect photographic retinal nerve fiber layer (RNFL) defects. Methods This retrospective cross-sectional study included 45 eyes of 45 consecutive glaucoma patients with RNFL defects in red-free fundus photographs. The superior and inferior temporal quadrants in each eye were included for data analysis separately. The location and presence of RNFL defects seen in red-free fundus photographs were compared with those seen in GDx-VCC deviation maps and OCT RNFL analysis maps for each quadrant. Results Of the 90 quadrants (45 eyes), 31 (34%) had no apparent RNFL defects, 29 (32%) had focal RNFL defects, and 30 (33%) had diffuse RNFL defects in red-free fundus photographs. The highest agreement between GDx-VCC and red-free photography was 73% when we defined GDx-VCC RNFL defects as a cluster of three or more color-coded squares (p<5%) along the traveling line of the retinal nerve fiber in the GDx-VCC deviation map (kappa value, 0.388; 95% confidence interval (CI), 0.195 to 0.582). The highest agreement between OCT and red-free photography was 85% (kappa value, 0.666; 95% CI, 0.506 to 0.825) when a value of 5% outside the normal limit for the OCT analysis map was used as a cut-off value for OCT RNFL defects. Conclusions According to the kappa values, the agreement between GDx-VCC deviation maps and red-free photography was poor, whereas the agreement between OCT analysis maps and red-free photography was good. PMID:19794943

IR thermography methods for evaluation of internal defects in light composite armours

International Nuclear Information System (INIS)

Swiderski, W.; Szabra, D.; Szudrowicz, M.

2009-01-01

Complete text of publication follows. Light composite armour is a preferred solution against military and paramilitary sources of present threats as the reducing mass of battle vehicles provides a possibility of their quick air-transport. The light armours of these vehicles should be resistant against: common and rifle bullets, grenades, anti-personal mines, IED - improvised explosive devices. The range of military applications anticipated for composite armours covers a broad spectrum of materials and designs. Materials of composite armours include graphite epoxy, glass epoxy and aramid fiber composites. The composites that have been examined can include a variety of defects, such as ballistic impacts, embedded defects, manufacturing defects, thermal damage, moisture ingress and other induced defects. Methods for testing ballistic protection of light armours are known and used. First of all they consist of checking armours resistance against the bullets where the bullet velocity is known. Moreover the V50 velocity is defined during the test. In this method the V 50 velocity of a round or standard fragment is defined (according to STANAG 2920) as the velocity at which armour is penetrated at the probability 50%. The distribution of points hit by bullets or fragments on the surface of an armour is also important. In fact, only correct distribution of these points provides a guaranty for an impartial assessment of tested designs. After hitting by a bullet, shape and size of an area of damage in composite armours depends on the type and design of armour, and type of reinforcing material is particularly important. Knowledge of damage characteristics allows to arrange hitting points to avoid overlapping of damaged areas. Nondestructive testing by using IR thermography methods is very useful in evaluation of internal defects. In the paper we present the dependence between the energy of fragments/or bullets and the dimension of internal defects. (author)

Large-Scale Molecular Simulations on the Mechanical Response and Failure Behavior of a defective Graphene: Cases of 5-8-5 Defects

Science.gov (United States)

Wang, Shuaiwei; Yang, Baocheng; Yuan, Jinyun; Si, Yubing; Chen, Houyang

2015-10-01

Understanding the effect of defects on mechanical responses and failure behaviors of a graphene membrane is important for its applications. As examples, in this paper, a family of graphene with various 5-8-5 defects are designed and their mechanical responses are investigated by employing molecular dynamics simulations. The dependence of fracture strength and strain as well as Young’s moduli on the nearest neighbor distance and defect types is examined. By introducing the 5-8-5 defects into graphene, the fracture strength and strain become smaller. However, the Young’s moduli of DL (Linear arrangement of repeat unit 5-8-5 defect along zigzag-direction of graphene), DS (a Slope angle between repeat unit 5-8-5 defect and zigzag direction of graphene) and DZ (Zigzag-like 5-8-5 defects) defects in the zigzag direction become larger than those in the pristine graphene in the same direction. A maximum increase of 11.8% of Young’s modulus is obtained. Furthermore, the brittle cracking mechanism is proposed for the graphene with 5-8-5 defects. The present work may provide insights in controlling the mechanical properties by preparing defects in the graphene, and give a full picture for the applications of graphene with defects in flexible electronics and nanodevices.

Research on Mechanisms and Controlling Methods of Macro Defects in TC4 Alloy Fabricated by Wire Additive Manufacturing.

Science.gov (United States)

Ji, Lei; Lu, Jiping; Tang, Shuiyuan; Wu, Qianru; Wang, Jiachen; Ma, Shuyuan; Fan, Hongli; Liu, Changmeng

2018-06-28

Wire feeding additive manufacturing (WFAM) has broad application prospects because of its advantages of low cost and high efficiency. However, with the mode of lateral wire feeding, including wire and laser additive manufacturing, gas tungsten arc additive manufacturing etc., it is easy to generate macro defects on the surface of the components because of the anisotropy of melted wire, which limits the promotion and application of WFAM. In this work, gas tungsten arc additive manufacturing with lateral wire feeding is proposed to investigate the mechanisms of macro defects. The results illustrate that the defect forms mainly include side spatters, collapse, poor flatness, and unmelted wire. It was found that the heat input, layer thickness, tool path, and wire curvature can have an impact on the macro defects. Side spatters are the most serious defects, mainly because the droplets cannot be transferred to the center of the molten pool in the lateral wire feeding mode. This research indicates that the macro defects can be controlled by optimizing the process parameters. Finally, block parts without macro defects were fabricated, which is meaningful for the further application of WFAM.

Analysis of Side-Wall Structure of Grown-in Twin-Type Octahedral Defects in Czochralski Silicon

Science.gov (United States)

Ueki, Takemi; Itsumi, Manabu; Takeda, Tadao

1998-04-01

We analyzed the side-wall structure of grown-in octahedral defects in Czochralski silicon standard wafers for large-scale integrated circuits. There are two types of twin octahedral defects: an overlapping type and an adjacent type. In the twin octahedral defects of the overlapping type, a hole is formed in the connection part. The side-wall layer in the hole part is formed continually and is the same thickness as the side-wall layers of both octahedrons. In the twin octahedral defects of the adjacent type, a partition layer is formed in the connection part. Our electron energy-loss spectroscopy analyses identified that the side-wall layer includes SiO2.

Purity and Defect Characterization of Single-Wall Carbon Nanotubes Using Raman Spectroscopy

Directory of Open Access Journals (Sweden)

Yasumitsu Miyata

2011-01-01

Full Text Available We investigated the purity and defects of single-wall carbon nanotubes (SWCNTs produced by various synthetic methods including chemical vapor deposition, arc discharge, and laser ablation. The SWCNT samples were characterized using scanning electron microscopy (SEM, thermogravimetric analysis (TGA, and Raman spectroscopy. Quantitative analysis of SEM images suggested that the G-band Raman intensity serves as an index for the purity. By contrast, the intensity ratio of G-band to D-band (G/D ratio reflects both the purity and the defect density of SWCNTs. The combination of G-band intensity and G/D ratio is useful for a quick, nondestructive evaluation of the purity and defect density of a SWCNT sample.

Model for transport and reaction of defects and carriers within displacement cascades in gallium arsenide

International Nuclear Information System (INIS)

Wampler, William R.; Myers, Samuel M.

2015-01-01

A model is presented for recombination of charge carriers at evolving displacement damage in gallium arsenide, which includes clustering of the defects in atomic displacement cascades produced by neutron or ion irradiation. The carrier recombination model is based on an atomistic description of capture and emission of carriers by the defects with time evolution resulting from the migration and reaction of the defects. The physics and equations on which the model is based are presented, along with the details of the numerical methods used for their solution. The model uses a continuum description of diffusion, field-drift and reaction of carriers, and defects within a representative spherically symmetric cluster of defects. The initial radial defect profiles within the cluster were determined through pair-correlation-function analysis of the spatial distribution of defects obtained from the binary-collision code MARLOWE, using recoil energies for fission neutrons. Properties of the defects are discussed and values for their parameters are given, many of which were obtained from density functional theory. The model provides a basis for predicting the transient response of III-V heterojunction bipolar transistors to displacement damage from energetic particle irradiation

Defect-Tolerant Monolayer Transition Metal Dichalcogenides

DEFF Research Database (Denmark)

Pandey, Mohnish; Rasmussen, Filip Anselm; Kuhar, Korina

2016-01-01

Localized electronic states formed inside the band gap of a semiconductor due to crystal defects can be detrimental to the material's optoelectronic properties. Semiconductors with a lower tendency to form defect induced deep gap states are termed defect-tolerant. Here we provide a systematic first...... the gap. These ideas are made quantitative by introducing a descriptor that measures the degree of similarity of the conduction and valence band manifolds. Finally, the study is generalized to nonpolar nanoribbons of the TMDs where we find that only the defect sensitive materials form edge states within......-principles investigation of defect tolerance in 29 monolayer transition metal dichalcogenides (TMDs) of interest for nanoscale optoelectronics. We find that the TMDs based on group VI and X metals form deep gap states upon creation of a chalcogen (S, Se, Te) vacancy, while the TMDs based on group IV metals form only...

Production of freely-migrating defects during irradiation

International Nuclear Information System (INIS)

Rehn, L.E.; Okamoto, P.R.

1986-09-01

During irradiation at elevated temperatures, vacancy and interstitial defects that escape can produce several different types of microstructural changes. Hence the production rate of freely-migrating defects must be known as a function of irradiating particle species and energy before quantitative correlations can be made between microstructural changes. Our fundamental knowledge of freely-migrating defect production has increased substantially in recent years. Critical experimental findings that led to the improved understanding are reviewed in this paper. A strong similarity is found for the dependence of freely-migrating defect production on primary recoil energy as measured in a variety of metals and alloys by different authors. The efficiency for producing freely-migrating defects decreases much more strongly with increasing primary recoil energy than does the efficiency for creating stable defects at liquid helium temperatures. The stronger decrease can be understood in terms of additional intracascade recombination that results from the nonrandom distribution of defects existing in the primary damage state for high primary recoil energies. Although the existing data base is limited to fcc materials, the strong similarity in the reported investigations suggests that the same dependence of freely-migrating defect production on primary recoil energy may be characteristic of a wide variety of other alloy systems as well. 52 refs., 4 figs

Detecting Topological Defect Dark Matter Using Coherent Laser Ranging System

Science.gov (United States)

Yang, Wanpeng; Leng, Jianxiao; Zhang, Shuangyou; Zhao, Jianye

2016-01-01

In the last few decades, optical frequency combs with high intensity, broad optical bandwidth, and directly traceable discrete wavelengths have triggered rapid developments in distance metrology. However, optical frequency combs to date have been limited to determine the absolute distance to an object (such as satellite missions). We propose a scheme for the detection of topological defect dark matter using a coherent laser ranging system composed of dual-combs and an optical clock via nongravitational signatures. The dark matter field, which comprises a defect, may interact with standard model particles, including quarks and photons, resulting in the alteration of their masses. Thus, a topological defect may function as a dielectric material with a distinctive frequency-depend index of refraction, which would cause the time delay of a periodic extraterrestrial or terrestrial light. When a topological defect passes through the Earth, the optical path of long-distance vacuum path is altered, this change in optical path can be detected through the coherent laser ranging system. Compared to continuous wavelength(cw) laser interferometry methods, dual-comb interferometry in our scheme excludes systematic misjudgement by measuring the absolute optical path length. PMID:27389642

Repair of a mandibular defect with a free vascularized coccygeal vertebra transfer in a dog.

Science.gov (United States)

Yeh, L S; Hou, S M

1994-01-01

Bilateral mandibular defects in a male mongrel dog were repaired. On the left side, a free vascularized coccygeal bone graft that included the median caudal artery and caudal vein was used to correct the defect. On the right side, the defect was bridged with a bone plate and screws. For further immobilization, the muzzle was temporarily taped for 3 weeks and a pharyngostomy tube was used for nutritional support. The dog was able to eat dry commercial food satisfactorily within 2 months of surgery despite mild malocclusion. Radiographs taken 2 months and 18 months postoperatively showed bony union with graft hypertrophy in the left mandible, whereas the right mandibular defect showed protracted nonunion. The results indicate that vascularized coccygeal vertebra transfer provides an alternative for the management of canine mandibular defects.

Human diseases associated with defective DNA repair

International Nuclear Information System (INIS)

Friedberg, E.C.; Ehmann, U.K.; Williams, J.I.

1979-01-01

The observations on xeroderma pigmentosum (XP) cells in culture were the first indications of defective DNA repair in association with human disease. Since then, a wealth of information on DNA repair in XP, and to a lesser extent in other diseases, has accumulated in the literature. Rather than clarifying the understanding of DNA repair mechanisms in normal cells and of defective DNA repair in human disease, the literature suggests an extraordinary complexity of both of the phenomena. In this review a number of discrete human diseases are considered separately. An attempt was made to systematically describe the pertinent clinical features and cellular and biochemical defects in these diseases, with an emphasis on defects in DNA metabolism, particularly DNA repair. Wherever possible observations have been correlated and unifying hypotheses presented concerning the nature of the basic defect(s) in these diseases. Discussions of the following diseases are presented: XP, ataxia telangiectasia; Fanconi's anemia; Hutchinson-Gilford progeria syndrome; Bloom's syndrome, Cockayne's syndrome; Down's syndrome; retinoblastoma; chronic lymphocytic leukemia; and other miscellaneous human diseases with possble DNA repair defects

Defect tolerance in resistor-logic demultiplexers for nanoelectronics.

Science.gov (United States)

Kuekes, Philip J; Robinett, Warren; Williams, R Stanley

2006-05-28

Since defect rates are expected to be high in nanocircuitry, we analyse the performance of resistor-based demultiplexers in the presence of defects. The defects observed to occur in fabricated nanoscale crossbars are stuck-open, stuck-closed, stuck-short, broken-wire, and adjacent-wire-short defects. We analyse the distribution of voltages on the nanowire output lines of a resistor-logic demultiplexer, based on an arbitrary constant-weight code, when defects occur. These analyses show that resistor-logic demultiplexers can tolerate small numbers of stuck-closed, stuck-open, and broken-wire defects on individual nanowires, at the cost of some degradation in the circuit's worst-case voltage margin. For stuck-short and adjacent-wire-short defects, and for nanowires with too many defects of the other types, the demultiplexer can still achieve error-free performance, but with a smaller set of output lines. This design thus has two layers of defect tolerance: the coding layer improves the yield of usable output lines, and an avoidance layer guarantees that error-free performance is achieved.

Altering graphene line defect properties using chemistry

Science.gov (United States)

Vasudevan, Smitha; White, Carter; Gunlycke, Daniel

2012-02-01

First-principles calculations are presented of a fundamental topological line defect in graphene that was observed and reported in Nature Nanotech. 5, 326 (2010). These calculations show that atoms and smaller molecules can bind covalently to the surface in the vicinity of the graphene line defect. It is also shown that the chemistry at the line defect has a strong effect on its electronic and magnetic properties, e.g. the ferromagnetically aligned moments along the line defect can be quenched by some adsorbates. The strong effect of the adsorbates on the line defect properties can be understood by examining how these adsorbates affect the boundary-localized states in the vicinity of the Fermi level. We also expect that the line defect chemistry will significantly affect the scattering properties of incident low-energy particles approaching it from graphene.

Challenges in the reconstruction of bilateral maxillectomy defects.

Science.gov (United States)

Joseph, Shawn T; Thankappan, Krishnakumar; Buggaveeti, Rahul; Sharma, Mohit; Mathew, Jimmy; Iyer, Subramania

2015-02-01

Bilateral maxillectomy defects, if not adequately reconstructed, can result in grave esthetic and functional problems. The purpose of this study was to investigate the outcome of reconstruction of such defects. This is a retrospective case series. The defects were analyzed for their components and the flaps used for reconstruction. Outcomes for flap loss and functional indices, including oral diet, speech, and dental rehabilitation, also were evaluated. Ten consecutive patients who underwent bilateral maxillectomy reconstruction received 14 flaps. Six patients had malignancies of the maxilla, and 4 patients had nonmalignant indications. Ten bony free flaps were used. Four soft tissue flaps were used. The fibula free flap was the most common flap used. Three patients had total flap loss. Seven patients were alive and available for functional evaluation. Of these, 4 were taking an oral diet with altered consistency and 2 were on a regular diet. Speech was intelligible in all patients. Only 2 patients opted for dental rehabilitation with removable dentures. Reconstruction after bilateral maxillectomy is essential to prevent esthetic and functional problems. Bony reconstruction is ideal. The fibula bone free flap is commonly used. The complexity of the defect makes reconstruction difficult and the initial success rate of free flaps is low. Secondary reconstructions after the initial flap failures were successful. A satisfactory functional outcome can be achieved. Copyright © 2015 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.

FOREWORD International Conference on Defects in Insulating Materials

Science.gov (United States)

Valerio, Mário Ernesto Giroldo; Jackson, R. A.

2010-11-01

These proceedings represent a sample of the scientific works presented during ICDIM2008, the 16th International Conference on Defects in Insulating Materials, held at the Federal University of Sergipe, Aracaju, Brazil from 24-29 August 2008. The conference was the latest in a series which began at Argonne in 1956, and which has been held most recently in Riga, Latvia (2004) and Johannesburg, South Africa (2000). The conference was also related scientifically to the EURODIM series, which have been held most recently in Milan, Italy (2006), Wroclaw, Poland (2002) and Pecs, Hungary (2010). The aim of the conference was to bring together physicists, chemists and materials scientist to discuss defects in insulating materials and their effect on materials, including their optical, mass/charge transport, energy storage and sensor properties. The conference featured 6 plenary lectures, 60 contributed lectures and about 130 posters. The posters were displayed for the whole conference, but discussed in two three-hour sessions. We are grateful to the International Advisory Committee for suggesting invited speakers and to the Programme Committee for their help in refereeing all the abstracts and choosing the contributed oral contributions. We would also like to thank the Local Organising Committee and the Brazilian Physical Society for their help with local organisation and the online registration/payment process respectively. The chairpersons would like to specially thanks all the sponsors listed below for financial support. The Federal University of Sergipe, one of the public and 'free tuition' Universities of the Country, run by the Brazilian Ministry of Education, were pleased to host this 16th meeting, the first one in Latin America. Mario E G Valerio Conference Chair Robert A Jackson Programme Chair Conference Scope Scope of the Conference was the presentation of the latest investigations on point and extended defects in bulk materials and thin films. Technological

Interventions for visual field defects in patients with stroke.

Science.gov (United States)

Pollock, Alex; Hazelton, Christine; Henderson, Clair A; Angilley, Jayne; Dhillon, Baljean; Langhorne, Peter; Livingstone, Katrina; Munro, Frank A; Orr, Heather; Rowe, Fiona J; Shahani, Uma

2011-10-05

Visual field defects are estimated to affect 20% to 57% of people who have had a stroke. Visual field defects can affect functional ability in activities of daily living (commonly affecting mobility, reading and driving), quality of life, ability to participate in rehabilitation, and depression, anxiety and social isolation following stroke. There are many interventions for visual field defects, which are proposed to work by restoring the visual field (restitution); compensating for the visual field defect by changing behaviour or activity (compensation); substituting for the visual field defect by using a device or extraneous modification (substitution); or ensuring appropriate diagnosis, referral and treatment prescription through standardised assessment or screening, or both. To determine the effects of interventions for people with visual field defects after stroke. We searched the Cochrane Stroke Group Trials Register (February 2011), the Cochrane Eyes and Vision Group Trials Register (December 2009) and nine electronic bibliographic databases including CENTRAL (The Cochrane Library 2009, Issue 4), MEDLINE (1950 to December 2009), EMBASE (1980 to December 2009), CINAHL (1982 to December 2009), AMED (1985 to December 2009), and PsycINFO (1967 to December 2009). We also searched reference lists and trials registers, handsearched journals and conference proceedings and contacted experts. Randomised trials in adults after stroke, where the intervention was specifically targeted at improving the visual field defect or improving the ability of the participant to cope with the visual field loss. The primary outcome was functional ability in activities of daily living and secondary outcomes included functional ability in extended activities of daily living, reading ability, visual field measures, balance, falls, depression and anxiety, discharge destination or residence after stroke, quality of life and social isolation, visual scanning, adverse events and death. Two

Stability and kinetics of point defects in SiO2 and in SiC

International Nuclear Information System (INIS)

Roma, G.

2012-01-01

This document is conceived as an overview of Guido Roma's research achievements on defects stability and kinetics in two materials of interest in nuclear science and for many other application domains: silicon dioxide and silicon carbide. An extended summary in french is followed by the main document, in english. Chapter 1 describes the context, introduces the approach and explains the choice of silicon dioxide and silicon carbide. Chapter 2 discusses several approximations and specific issues of the application of Density Functional Theory to point defects in non-metallic materials for the study of defects energetics and diffusion. Chapter 3 is devoted to native defects in silicon dioxide and the understanding of self-diffusion in crystalline and amorphous SiO 2 . Chapter 4 summarises the results on native defects and palladium impurities in silicon carbide. A conclusion, including suggestions for future developments, closes the main part of the document. (author) [fr

Iatrogenic Urethral Defect Repairment: A Case Report

Directory of Open Access Journals (Sweden)

Ulas Fidan

2013-10-01

Full Text Available    Iatrogenic urethral defect is a complication that occurs after vaginal surgical procedures. Many surgical methods according to place of defect are described in case of injury of urethra. In this article, we reported the repairment of distal urethral defect with the help of greft taken from labia minor. This defect is made by the excision of the granulation tissue that occurred after chronic paraurethral  gland infection.

Repairing Nanoparticle Surface Defects.

Science.gov (United States)

Marino, Emanuele; Kodger, Thomas E; Crisp, Ryan W; Timmerman, Dolf; MacArthur, Katherine E; Heggen, Marc; Schall, Peter

2017-10-23

Solar devices based on semiconductor nanoparticles require the use of conductive ligands; however, replacing the native, insulating ligands with conductive metal chalcogenide complexes introduces structural defects within the crystalline nanostructure that act as traps for charge carriers. We utilized atomically thin semiconductor nanoplatelets as a convenient platform for studying, both microscopically and spectroscopically, the development of defects during ligand exchange with the conductive ligands Na 4 SnS 4 and (NH 4 ) 4 Sn 2 S 6 . These defects can be repaired via mild chemical or thermal routes, through the addition of L-type ligands or wet annealing, respectively. This results in a higher-quality, conductive, colloidally stable nanomaterial that may be used as the active film in optoelectronic devices. © 2017 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA.

Reproductive output of mosses under experimental warming on Fildes Peninsula, King George Island, maritime Antarctica

OpenAIRE

Casanova-Katny, A.; Torres-Mellado, G. A.; Eppley, S. M.

2016-01-01

BACKGROUND: Mosses dominate much of the vegetation in the Antarctic, but the effect of climatic change on moss growth and sexual reproduction has scarcely been studied. In Antarctica, mosses infrequently produce sporophytes; whether this is due to physiological limitation or an adaptive response is unknown. We studied the effect of experimental warming (with Open Top Chambers, OTCs) on sporophyte production on Fildes Peninsula, King George Island for four moss species (Bartramia patens, Henne...

Management of segmental bony defects: the role of osteoconductive orthobiologics.

Science.gov (United States)

McKee, Michael D

2006-01-01

Our knowledge about, and the availability of, orthobiologic materials has increased exponentially in the last decade. Although previously confined to the experimental or animal-model realm, several orthobiologics have been shown to be useful in a variety of clinical situations. As surgical techniques in vascular anastomosis, soft-tissue coverage, limb salvage, and fracture stabilization have improved, the size and frequency of bony defects (commensurate with the severity of the initial injury) have increased, as well. Because all methods of managing segmental bony defects have drawbacks, a need remains for a readily available, void-filling, inexpensive bone substitute. Such a bone substitute fulfills a permissive role in allowing new bone to grow into a given defect. Such potential osteoconductive materials include ceramics, calcium sulfate or calcium phosphate compounds, hydroxyapatite, deproteinized bone, corals, and recently developed polymers. Some materials that have osteoinductive properties, such as demineralized bone matrix, also display prominent osteoconductive properties.

The carbon-substitutional-carbon-interstitial (CsCi) defect pair in silicon from hybrid functional calculations

CSIR Research Space (South Africa)

Ouma, CNM

2016-06-01

Full Text Available defects and defect complexes. Very few theoretical studies have attempted to investigate defect metastability[23,24]. 2.0 Computational details All DFT calculations were done based on the generalized Kohn-Sham approach[25] and the projector... (2014) 141–143. [25] W. Kohn, L.J. Sham, Self-Consistent Equations Including Exchange and Correlation Effects, Phys. Rev. 140 (1965) A1133–A1138. doi:10.1103/PhysRev.140.A1133. [26] G. Kresse, D. Joubert, From ultrasoft pseudopotentials...

Aspects of defects in 3d-3d correspondence

International Nuclear Information System (INIS)

Gang, Dongmin; Kim, Nakwoo; Romo, Mauricio; Yamazaki, Masahito

2016-01-01

In this paper we study supersymmetric co-dimension 2 and 4 defects in the compactification of the 6d (2,0) theory of type A_N_−_1 on a 3-manifold M. The so-called 3d-3d correspondence is a relation between complexified Chern-Simons theory (with gauge group SL(N,ℂ)) on M and a 3d N=2 theory T_N[M]. We study this correspondence in the presence of supersymmetric defects, which are knots/links inside the 3-manifold. Our study employs a number of different methods: state-integral models for complex Chern-Simons theory, cluster algebra techniques, domain wall theory T[SU(N)], 5d N=2 SYM, and also supergravity analysis through holography. These methods are complementary and we find agreement between them. In some cases the results lead to highly non-trivial predictions on the partition function. Our discussion includes a general expression for the cluster partition function, which can be used to compute in the presence of maximal and certain class of non-maximal punctures when N>2. We also highlight the non-Abelian description of the 3d N=2T_N[M] theory with defect included, when such a description is available. This paper is a companion to our shorter paper http://dx.doi.org/10.1088/1751-8113/49/30/30LT02, which summarizes our main results.

[Progress of Masquelet technique to repair bone defect].

Science.gov (United States)

Yin, Qudong; Sun, Zhenzhong; Gu, Sanjun

2013-10-01

To summarize the progress of Masquelet technique to repair bone defect. The recent literature concerning the application of Masquelet technique to repair bone defect was extensively reviewed and summarized. Masquelet technique involves a two-step procedure. First, bone cement is used to fill the bone defect after a thorough debridement, and an induced membrane structure surrounding the spacer formed; then the bone cement is removed after 6-8 weeks, and rich cancellous bone is implanted into the induced membrane. Massive cortical bone defect is repaired by new bone forming and consolidation. Experiments show that the induced membrane has vascular system and is also rich in vascular endothelial growth factor, transforming growth factor beta1, bone morphogenetic protein 2, and bone progenitor cells, so it has osteoinductive property; satisfactory results have been achieved in clinical application of almost all parts of defects, various types of bone defect and massive defect up to 25 cm long. Compared with other repair methods, Masquelet technique has the advantages of reliable effect, easy to operate, few complications, low requirements for recipient site, and wide application. Masquelet technique is an effective method to repair bone defect and is suitable for various types of bone defect, especially for bone defects caused by infection and tumor resection.

Prevention of congenital defects induced by prenatal alcohol exposure (Conference Presentation)

Science.gov (United States)

Sheehan, Megan M.; Karunamuni, Ganga; Pedersen, Cameron J.; Gu, Shi; Doughman, Yong Qiu; Jenkins, Michael W.; Watanabe, Michiko; Rollins, Andrew M.

2017-02-01

Over 500,000 women per year in the United States drink during pregnancy, and 1 in 5 of this population also binge drink. Up to 40% of live-born children with prenatal alcohol exposure (PAE) present with congenital heart defects (CHDs) including life-threatening outflow and valvuloseptal anomalies. Previously we established a PAE model in the avian embryo and used optical coherence tomography (OCT) imaging to assay looping-stage (early) cardiac function/structure and septation-stage (late) cardiac defects. Early-stage ethanol-exposed embryos had smaller cardiac cushions (valve precursors) and increased retrograde flow, while late-stage embryos presented with gross head/body defects, and exhibited smaller atrio-ventricular (AV) valves, interventricular septae, and aortic vessels. However, supplementation with the methyl donor betaine reduced gross defects, prevented cardiac defects such as ventricular septal defects and abnormal AV valves, and normalized cardiac parameters. Immunofluorescent staining for 5-methylcytosine in transverse embryo sections also revealed that DNA methylation levels were reduced by ethanol but normalized by co-administration of betaine. Furthermore, supplementation with folate, another methyl donor, in the PAE model appeared to normalize retrograde flow levels which are typically elevated by ethanol exposure. Studies are underway to correlate retrograde flow numbers for folate with associated cushion volumes. Finally, preliminary findings have revealed that glutathione, a key endogenous antioxidant which also regulates methyl group donation, is particularly effective in improving alcohol-impacted survival and gross defect rates. Current investigations will determine whether glutathione has any positive effect on PAE-related CHDs. Our studies could have significant implications for public health, especially related to prenatal nutrition recommendations.

The defect chemistry of UO2 ± x from atomistic simulations

Science.gov (United States)

Cooper, M. W. D.; Murphy, S. T.; Andersson, D. A.

2018-06-01

Control of the defect chemistry in UO2 ± x is important for manipulating nuclear fuel properties and fuel performance. For example, the uranium vacancy concentration is critical for fission gas release and sintering, while all oxygen and uranium defects are known to strongly influence thermal conductivity. Here the point defect concentrations in thermal equilibrium are predicted using defect energies from density functional theory (DFT) and vibrational entropies calculated using empirical potentials. Electrons and holes have been treated in a similar fashion to other charged defects allowing for structural relaxation around the localized electronic defects. Predictions are made for the defect concentrations and non-stoichiometry of UO2 ± x as a function of oxygen partial pressure and temperature. If vibrational entropy is omitted, oxygen interstitials are predicted to be the dominant mechanism of excess oxygen accommodation over only a small temperature range (1265 K-1350 K), in contrast to experimental observation. Conversely, if vibrational entropy is included oxygen interstitials dominate from 1165 K to 1680 K (Busker potential) or from 1275 K to 1630 K (CRG potential). Below these temperature ranges, excess oxygen is predicted to be accommodated by uranium vacancies, while above them the system is hypo-stoichiometric with oxygen deficiency accommodated by oxygen vacancies. Our results are discussed in the context of oxygen clustering, formation of U4O9, and issues for fuel behavior. In particular, the variation of the uranium vacancy concentrations as a function of temperature and oxygen partial pressure will underpin future studies into fission gas diffusivity and broaden the understanding of UO2 ± x sintering.

Delayed closure of the palatal defect using buccal inversion and palatal rotation flaps after maxillectomy.

Science.gov (United States)

Jung, Seunggon; Kook, Min-Suk; Park, Hong-Ju; Oh, Hee-Kyun

2013-03-01

Maxillectomy leaves oronasal and oroantral defects that result in functional impairment of mastication, deglutition, and speech. Many treatment options are suggested and tried including the palatal flap as local flap. Although palatal flaps have been used to repair various oral cavity defects, they have certain limitations due to the dimensions. The amount and location of the palatal tissues available are important for palatal repair. Secondary intentional healing after maxillectomy will allow the epithelialization of the defect margin adjacent to remained palate, and there will be more mucosa that is available for closure of the defect. We delayed the closure of the palatal defect, while the patient underwent prosthetic treatment for functional recovery in 5 maxillectomy patients. Delayed closure of palatal defect with local flap was done at 10.8 ± 7.9 months after the maxillectomy. While delayed closure in hemimaxillectomy patients left postoperative fistula, it provided separation of the oral cavity and nasal/sinus cavity and adequate surface for prosthesis in partial maxillectomy patients.

Optical properties of GaSb(001)-c(2 x 6): The role of surface antisite defects

Energy Technology Data Exchange (ETDEWEB)

Hogan, Conor; Del Sole, Rodolfo [Department of Physics, CNR-INFM-SMC, Roma (Italy); European Theoretical Spectroscopy Facility (ETSF), University of Rome ' ' Tor Vergata' ' , Roma (Italy); Magri, Rita [Centro S3-CNR-Istituto di Nanoscienze, Modena (Italy); Department of Physics, University of Modena and Reggio Emilia, Modena (Italy)

2010-08-15

We consider the formation of surface antisite defects on a previously proposed model for the GaSb(001)-c(2 x 6) surface. Based on ab initio total energy calculations, we show how these defects stabilize the otherwise metallic surface and how their formation is driven by the excess charge associated with the Sb-rich surface conditions. The surface-sensitive optical technique of reflectance anisotropy spectroscopy is shown to be crucial for detecting the defects, and computation of spectra yields a good agreement with experiment when defects are included in the surface reconstruction. (Abstract Copyright [2010], Wiley Periodicals, Inc.)

Defect pin behaviour in the DFR

International Nuclear Information System (INIS)

Sloss, W.M.; Bagley, K.Q.; Edmonds, E.; Potter, P.E.

1979-01-01

A program of defective fuel pin irradiations has been carried out in the DFR. This program employed fuel pins which had failed during previous irradiations (natural defects) and pins in which simulated failures (artificial defects) had been induced prior to irradiation or during an intermediate examination stage at moderate or substantial burnups. The artificial defects simulated longitudinal ruptures and were normally located at positions near the top, middle and bottom of the pin where clad temperatures were 450, 540 and 630 0 C respectively. The fuel was mixed U-Pu oxide, and fuel form, stoichiometry, clad type, pin diameter, linear rating, and burnup were among the variables examined. The defect pin tests were normally carried out in single pin or trefoil type vehicles. After irradiation all the pins were subjected to the normal nondestructive examination procedures and the visual, radiographic, gamma-scanning, and dimensional change results are presented. Several pins were destructively examined and the metallographic data are discussed

Defect kinetics in novel detector materials

CERN Document Server

MacEvoy, B C

2000-01-01

Silicon particle detectors will be used extensively in experiments at the CERN Large Hadron Collider, where unprecedented particle fluences will cause significant atomic displacement damage. We present a model of the evolution of defect concentrations and consequent electrical behaviour in "novel" detector materials with various oxygen and carbon impurity concentrations. The divacancy-oxygen (V/sub 2/O) defect is identified as the cause of changes in device characteristics during /sup 60/Co gamma irradiation. In the case of hadron irradiation changes in detector doping concentration (N/sub eff/) are dominated by cluster defects, in particular the divacancy (V/sub 2/), which exchange charge directly via a non-Shockley-Read- Hall mechanism. The V/sub 2/O defect also contributes to Ne/sub eff/. This defect is more copiously produced during 24 GeV/c proton irradiation than during 1 MeV neutron irradiation on account of the higher vacancy introduction rate, hence the radiation hardness of materials is more sensiti...

Positron annihilation spectroscopy in defects of semiconductors

International Nuclear Information System (INIS)

Fujinami, Masanori

2002-01-01

Interaction of positron and defects, application to research of defects of semiconductor and defects on the surface of semiconductor are explained. Cz (Czochralski)-Si single crystal with 10 18 cm -3 impurity oxygen was introduced defects by electron irradiation and the positron lifetime was measured at 90K after annealing. The defect size and recovery temperature were determined by the lifetime measurement. The distribution of defects in the depth direction is shown by S-E curve. The chemical state analysis is possible by CBS (Coincidence Doppler Broadening) spectra. The application to silicon-implanted (100 keV, 2x10 15 cm -2 ) silicon and oxygen-implanted (180 keV, 2x10 15 cm -2 ) silicon are stated. On the oxygen-implanted silicon, the main product was V2 after implantation, V 6 O 2 at 600degC and V 10 O 6 at 800degC. (S.Y.)

Defects in semiconductors

International Nuclear Information System (INIS)

Pimentel, C.A.F.

1983-01-01

Some problems openned in the study of defects in semiconductors are presented. In particular, a review is made of the more important problems in Si monocrystals of basic and technological interest: microdefects and the presence of oxigen and carbon. The techniques usually utilized in the semiconductor material characterization are emphatized according its potentialities. Some applications of x-ray techniques in the epitaxial shell characterization in heterostructures, importants in electronic optics, are shown. The increase in the efficiency of these defect analysis methods in semiconductor materials with the use of synchrotron x-ray sources is shown. (L.C.) [pt

Assisted reproductive technology and major birth defects in Western Australia.

Science.gov (United States)

Hansen, Michele; Kurinczuk, Jennifer J; de Klerk, Nicholas; Burton, Peter; Bower, Carol

2012-10-01

To estimate the prevalence of major birth defects diagnosed by 6 years of age in all births and terminations of pregnancy for fetal anomaly conceived by assisted reproductive technology (when this included intracytoplasmic sperm injection and in vitro fertilization [IVF]) and the remainder of nonassisted reproductive technology-conceived children born in Western Australia from 1994 to 2002. This retrospective cohort study used data linkage between three population-based registers (Reproductive Technology Register, Western Australian Register of Developmental Anomalies, and Midwives' Notification of Birth System) to identify all assisted reproductive technology (n=2,911) and nonassisted reproductive technology (n=210,997) births with and without birth defects diagnosed by age 6 and all terminations of pregnancy for fetal anomaly. A major birth defect was diagnosed in 8.7% of assisted reproductive technology and 5.4% of nonassisted reproductive technology singletons (odds ratio [OR] 1.53, 95% confidence interval [CI] 1.30-1.79), as well as 7.1% of assisted reproductive technology twins and 5.9% of nonassisted reproductive technology twins of unlike sex (OR 1.08, 95% CI 0.77-1.51). The prevalence of birth defects in assisted reproductive technology singletons and twins decreased markedly over the study period. This change was evident across all three clinics contributing data over the whole study and was particularly marked for children conceived as a result of IVF. There has been a decrease in the prevalence of birth defects over time in children born as a result of assisted reproductive technology in Western Australia; however, the prevalence of major birth defects in assisted reproductive technology singletons remains increased compared with nonassisted reproductive technology singletons. II.

Wafer plane inspection for advanced reticle defects

Science.gov (United States)

Nagpal, Rajesh; Ghadiali, Firoz; Kim, Jun; Huang, Tracy; Pang, Song

2008-05-01

Readiness of new mask defect inspection technology is one of the key enablers for insertion & transition of the next generation technology from development into production. High volume production in mask shops and wafer fabs demands a reticle inspection system with superior sensitivity complemented by a low false defect rate to ensure fast turnaround of reticle repair and defect disposition (W. Chou et al 2007). Wafer Plane Inspection (WPI) is a novel approach to mask defect inspection, complementing the high resolution inspection capabilities of the TeraScanHR defect inspection system. WPI is accomplished by using the high resolution mask images to construct a physical mask model (D. Pettibone et al 1999). This mask model is then used to create the mask image in the wafer aerial plane. A threshold model is applied to enhance the inspectability of printing defects. WPI can eliminate the mask restrictions imposed on OPC solutions by inspection tool limitations in the past. Historically, minimum image restrictions were required to avoid nuisance inspection stops and/or subsequent loss of sensitivity to defects. WPI has the potential to eliminate these limitations by moving the mask defect inspections to the wafer plane. This paper outlines Wafer Plane Inspection technology, and explores the application of this technology to advanced reticle inspection. A total of twelve representative critical layers were inspected using WPI die-to-die mode. The results from scanning these advanced reticles have shown that applying WPI with a pixel size of 90nm (WPI P90) captures all the defects of interest (DOI) with low false defect detection rates. In validating CD predictions, the delta CDs from WPI are compared against Aerial Imaging Measurement System (AIMS), where a good correlation is established between WPI and AIMSTM.

Disinfection By-Product Exposures and the Risk of Specific Cardiac Birth Defects

Science.gov (United States)

Wright, J. Michael; Evans, Amanda; Kaufman, John A.; Rivera-Núñez, Zorimar; Narotsky, Michael G.

2016-01-01

Background: Epidemiological studies suggest that women exposed to disinfection by-products (DBPs) have an increased risk of delivering babies with cardiovascular defects (CVDs). Objective: We examined nine CVDs in relation to categorical DBP exposures including bromoform, chloroform, dibromochloromethane (DBCM), bromodichloromethane (BDCM), monobromoacetic acid (MBAA), dichloroacetic acid (DCAA), trichloroacetic acid (TCAA), and summary DBP measures (HAA5, THMBr, THM4, and DBP9). Methods: We calculated adjusted odds ratios (aORs) in a case–control study of birth defects in Massachusetts with complete quarterly 1999–2004 trihalomethane (THM) and haloacetic acid (HAA) data. We randomly matched 10 controls each to 904 CVD cases based on week of conception. Weight-averaged aggregate first-trimester DBP exposures were assigned to individuals based on residence at birth. Results: We detected associations for tetralogy of Fallot and the upper exposure categories for TCAA, DCAA, and HAA5 (aOR range, 3.34–6.51) including positive exposure–response relationships for DCAA and HAA5. aORs consistent in magnitude were detected between atrial septal defects and bromoform (aOR = 1.56; 95% CI: 1.01, 2.43), as well as DBCM, chloroform, and THM4 (aOR range, 1.26–1.67). Ventricular septal defects (VSDs) were associated with the highest bromoform (aOR = 1.85; 95% CI: 1.20, 2.83), MBAA (aOR = 1.81; 95% CI: 0.85, 3.84), and DBCM (aOR = 1.54; 95% CI: 1.00, 2.37) exposure categories. Conclusions: To our knowledge, this is the first birth defect study to develop multi-DBP adjusted regression models as well as the first CVD study to evaluate HAA exposures and the second to evaluate bromoform exposures. Our findings, therefore, inform exposure specificity for the consistent associations previously reported between THM4 and CVDs including VSDs. Citation: Wright JM, Evans A, Kaufman JA, Rivera-Núñez Z, Narotsky MG. 2017. Disinfection by-product exposures and the risk of specific

Energetics of intrinsic point defects in uranium dioxide from electronic-structure calculations

International Nuclear Information System (INIS)

Nerikar, Pankaj; Watanabe, Taku; Tulenko, James S.; Phillpot, Simon R.; Sinnott, Susan B.

2009-01-01

The stability range of intrinsic point defects in uranium dioxide is determined as a function of temperature, oxygen partial pressure, and non-stoichiometry. The computational approach integrates high accuracy ab initio electronic-structure calculations and thermodynamic analysis supported by experimental data. In particular, the density functional theory calculations are performed at the level of the spin polarized, generalized gradient approximation and includes the Hubbard U term; as a result they predict the correct anti-ferromagnetic insulating ground state of uranium oxide. The thermodynamic calculations enable the effects of system temperature and partial pressure of oxygen on defect formation energy to be determined. The predicted equilibrium properties and defect formation energies for neutral defect complexes match trends in the experimental literature quite well. In contrast, the predicted values for charged complexes are lower than the measured values. The calculations predict that the formation of oxygen interstitials becomes increasingly difficult as higher temperatures and reducing conditions are approached

Reduction of Defects in Jewelry Manufacturing

Science.gov (United States)

Ayudhya, Phitchaya Phanomwan na; Tangjitsitcharoen, Somkiat

2017-06-01

The aim of this research was to reduce the defects of gem bracelet found during manufacturing process at a jewelry company. It was found that gem bracelet product has the highest rejects compared to the rejects found in ring, earring, and pendant products. Types of defect were classified by using Pareto Diagram consisting of gem falling, seam, unclean casting, impinge, and deformation. The causes of defect were analyzed by Cause and Effect Diagram and applied Failure Mode and Effects Analysis (FMEA) was applied during manufacturing processes. This research found that the improvement of manufacturing process could reduce the Risk Priority Number (RPN) and total of all defects by 48.70% and 48.89%, respectively.

Ultrasonic defect detection method for socket welding joint

International Nuclear Information System (INIS)

Tominaga, Masaaki; Matsuo, Toshiyuki; Ueno, Akihiro; Watanabe, Kunimichi; Kawamata, Kunio.

1995-01-01

The present invention provides a method of detecting defects over a wide range of a socket weld portion of various kinds of pipelines used, for example, in a nuclear power plant. Namely, an inclined probe is disposed to a jig for detecting defects by ultrasonic waves. This is rotated at least by one turn along the peripheral surface of the material to be detected such as weld tube joints. Defects of weld portion of the material can be detected automatically by using ultrasonic waves during the rotation. The inclined probe for detecting defects by ultrasonic waves comprises a transmission portion having a planar transmittance oscillator disposed to a wedge on the transmission side and a receiving portion comprising a planar receiving oscillator disposed to a wedge on the receiving side. With such a constitution, ultrasonic waves are emitted from the transmission portion to the defect detection portion in the welded portion. If a defect is present, defective echo is reflected to the receiving portion disposed ahead of the probe. Since the defective echo changes depending on the height of the detective portion, the estimation of the height of the defect can be facilitated. (I.S.)

Tracking architectural defects in university building in Malaysia

Directory of Open Access Journals (Sweden)

Mohd Isa Haryati

2016-01-01

Full Text Available Building defects are always the key concern in the construction industry. Defects represent not only a loss to the project but also hamper the smooth operation of a building. Recognising the need to resolve these continuing problems, a research was mooted to track from the study of defects that occurred during the Defects Liability Period in a public university in Malaysia. This paper presents part of the research which investigates what can be learnt from the analysis of architectural defects in these projects. Two research objectives were developed (1 to investigate types of architectural defects that occurred and (2 to analyse the causes of the defects. A mixed methods approach is adopted. Data for the quantitative element of the research was drawn from defects audit records of the project. They were sorted, grouped and transferred into the SPSS software for analysis using the measure of central tendencies and frequency analysis. The findings suggest that with a proper methodology in place, defects can be effectively traced and categorised. This can provide very useful insights to their root cause and how this can be avoided in future projects.

Experimental study of defect power reactor fuel. Final report

International Nuclear Information System (INIS)

Forsyth, R.S.; Jonsson, T.

1982-01-01

Two BWR fuel rods, one intact and one defect, with the same manufacturing and irradiation data have been examined in a comparative study. The defect rod has been irradiated in a defect condition during approximately one reactor cycle and has consequently some secondary defects. The defect rod has two penetrating defects at a distance of about 1.5 meters from each other. Comparison with the intact rod shows a large Cs loss from the defect rod, especially between the cladding defects, where the loss is measured to about 30 %. The leachibility in deionized water is higher for Cs, U and Cm for fuel from the defect rod. The leaching results are more complex for Sr-90, Pu and Am. The fuel in the defect rod has undergone a change of structure with gain growth and formation of oriented fuel structure. The cladding of the defect rod is hydrided locally in some parts of the lower part of the rod and furthermore over a more extended region near the end of the rod. (Authors)

Channeling studies of impurity-defect interactions in silicon

International Nuclear Information System (INIS)

Wiggers, L.W.

1978-01-01

This thesis deals with the mechanism of defect production and interaction of introduced defects with impurity atoms in silicon single crystals. Defects are created by irradiation with energetic light particles (.2 - 3 MeV H + or He + ions). Mostly simple defects like vacancies and interstitials are produced during bombardment. (Auth.)

Fibrous metaphyseal defect (fibrous cortical defect, non-ossifying fibroma)

International Nuclear Information System (INIS)

Freyschmidt, J.; Saure, D.; Dammenhain, S.

1981-01-01

Fibrous cortical defect and nonossifying fibromas can be classified together as fibrous metaphyseal defects (FMD) since they have the same pahtological substrate, with a tendency to the same localisation around the knee, and occuring at the same age. They have a tendency to spontaneous healing, are clinically silent and are usually discovered accidentally during radiological examination. A radiological survey fo 5.674 metaphyseal regions in the upper and lower extremities of 2.065 unselected patients aged one to 20 years revealed an incidence of 1.8%; exlcusive examination of the distal femur showed an incidence of 2.7%. 96% of all lesions were in the lower extremities and only 4% in the upper. The marked discrepancy in the incidence rate between American and German publications is discussed. (orig.) [de

Noonan syndrome gain-of-function mutations in NRAS cause zebrafish gastrulation defects

Directory of Open Access Journals (Sweden)

Vincent Runtuwene

2011-05-01

Noonan syndrome is a relatively common developmental disorder that is characterized by reduced growth, wide-set eyes and congenital heart defects. Noonan syndrome is associated with dysregulation of the Ras–mitogen-activated-protein-kinase (MAPK signaling pathway. Recently, two mutations in NRAS were reported to be associated with Noonan syndrome, T50I and G60E. Here, we report a mutation in NRAS, resulting in an I24N amino acid substitution, that we identified in an individual bearing typical Noonan syndrome features. The I24N mutation activates N-Ras, resulting in enhanced downstream signaling. Expression of N-Ras-I24N, N-Ras-G60E or the strongly activating mutant N-Ras-G12V, which we included as a positive control, results in developmental defects in zebrafish embryos, demonstrating that these activating N-Ras mutants are sufficient to induce developmental disorders. The defects in zebrafish embryos are reminiscent of symptoms in individuals with Noonan syndrome and phenocopy the defects that other Noonan-syndrome-associated genes induce in zebrafish embryos. MEK inhibition completely rescued the activated N-Ras-induced phenotypes, demonstrating that these defects are mediated exclusively by Ras-MAPK signaling. In conclusion, mutations in NRAS from individuals with Noonan syndrome activated N-Ras signaling and induced developmental defects in zebrafish embryos, indicating that activating mutations in NRAS cause Noonan syndrome.

Noonan syndrome gain-of-function mutations in NRAS cause zebrafish gastrulation defects

Science.gov (United States)

Runtuwene, Vincent; van Eekelen, Mark; Overvoorde, John; Rehmann, Holger; Yntema, Helger G.; Nillesen, Willy M.; van Haeringen, Arie; van der Burgt, Ineke; Burgering, Boudewijn; den Hertog, Jeroen

2011-01-01

SUMMARY Noonan syndrome is a relatively common developmental disorder that is characterized by reduced growth, wide-set eyes and congenital heart defects. Noonan syndrome is associated with dysregulation of the Ras–mitogen-activated-protein-kinase (MAPK) signaling pathway. Recently, two mutations in NRAS were reported to be associated with Noonan syndrome, T50I and G60E. Here, we report a mutation in NRAS, resulting in an I24N amino acid substitution, that we identified in an individual bearing typical Noonan syndrome features. The I24N mutation activates N-Ras, resulting in enhanced downstream signaling. Expression of N-Ras-I24N, N-Ras-G60E or the strongly activating mutant N-Ras-G12V, which we included as a positive control, results in developmental defects in zebrafish embryos, demonstrating that these activating N-Ras mutants are sufficient to induce developmental disorders. The defects in zebrafish embryos are reminiscent of symptoms in individuals with Noonan syndrome and phenocopy the defects that other Noonan-syndrome-associated genes induce in zebrafish embryos. MEK inhibition completely rescued the activated N-Ras-induced phenotypes, demonstrating that these defects are mediated exclusively by Ras-MAPK signaling. In conclusion, mutations in NRAS from individuals with Noonan syndrome activated N-Ras signaling and induced developmental defects in zebrafish embryos, indicating that activating mutations in NRAS cause Noonan syndrome. PMID:21263000

Tutorial: Junction spectroscopy techniques and deep-level defects in semiconductors

Science.gov (United States)

Peaker, A. R.; Markevich, V. P.; Coutinho, J.

2018-04-01

The term junction spectroscopy embraces a wide range of techniques used to explore the properties of semiconductor materials and semiconductor devices. In this tutorial review, we describe the most widely used junction spectroscopy approaches for characterizing deep-level defects in semiconductors and present some of the early work on which the principles of today's methodology are based. We outline ab-initio calculations of defect properties and give examples of how density functional theory in conjunction with formation energy and marker methods can be used to guide the interpretation of experimental results. We review recombination, generation, and trapping of charge carriers associated with defects. We consider thermally driven emission and capture and describe the techniques of Deep Level Transient Spectroscopy (DLTS), high resolution Laplace DLTS, admittance spectroscopy, and scanning DLTS. For the study of minority carrier related processes and wide gap materials, we consider Minority Carrier Transient Spectroscopy (MCTS), Optical DLTS, and deep level optical transient spectroscopy together with some of their many variants. Capacitance, current, and conductance measurements enable carrier exchange processes associated with the defects to be detected. We explain how these methods are used in order to understand the behaviour of point defects and the determination of charge states and negative-U (Hubbard correlation energy) behaviour. We provide, or reference, examples from a wide range of materials including Si, SiGe, GaAs, GaP, GaN, InGaN, InAlN, and ZnO.

The Boomerang-shaped Pectoralis Major Musculocutaneous Flap for Reconstruction of Circular Defect of Cervical Skin.

Science.gov (United States)

Azuma, Shuchi; Arikawa, Masaki; Miyamoto, Shimpei

2017-11-01

We report on a patient with a recurrence of oral cancer involving a cervical lymph node. The patient's postexcision cervical skin defect was nearly circular in shape, and the size was about 12 cm in diameter. The defect was successfully reconstructed with a boomerang-shaped pectoralis major musculocutaneous flap whose skin paddle included multiple intercostal perforators of the internal mammary vessels. This flap design is effective for reconstructing an extensive neck skin defect and enables primary closure of the donor site with minimal deformity.

A magnetically tunable non-Bragg defect mode in a corrugated waveguide filled with liquid crystals

Science.gov (United States)

Zhang, Lu; Fan, Ya-Xian; Liu, Huan; Han, Xu; Lu, Wen-Qiang; Tao, Zhi-Yong

2018-04-01

A magnetically tunable, non-Bragg defect mode (NBDM) was created in the terahertz frequency range by inserting a defect in the middle of a periodically corrugated waveguide filled with liquid crystals (LCs). In the periodic waveguide, non-Bragg gaps beyond the Bragg ones, which appear in the transmission spectra, are created by different transverse mode resonances. The transmission spectra of the waveguide containing a defect showed that a defect mode was present inside the non-Bragg gap. The NBDM has quite different features compared to the Bragg defect mode, which includes more complex, high-order guided wave modes. In our study, we filled the corrugated waveguide with LCs to realize the tunability of the NBDM. The simulated results showed that the NBDM in a corrugated waveguide filled with LCs can be used in filters, sensors, switches, and other terahertz integrated devices.

Guiding, bending, and splitting of coupled defect surface modes in a surface-wave photonic crystal

Energy Technology Data Exchange (ETDEWEB)

Gao, Zhen; Gao, Fei [Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore, Singapore 637371 (Singapore); Zhang, Baile, E-mail: blzhang@ntu.edu.sg [Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore, Singapore 637371 (Singapore); Centre for Disruptive Photonic Technologies, Nanyang Technological University, Singapore, Singapore 637371 (Singapore)

2016-01-25

We experimentally demonstrate a type of waveguiding mechanism for coupled surface-wave defect modes in a surface-wave photonic crystal. Unlike conventional spoof surface plasmon waveguides, waveguiding of coupled surface-wave defect modes is achieved through weak coupling between tightly localized defect cavities in an otherwise gapped surface-wave photonic crystal, as a classical wave analogue of tight-binding electronic wavefunctions in solid state lattices. Wave patterns associated with the high transmission of coupled defect surface modes are directly mapped with a near-field microwave scanning probe for various structures including a straight waveguide, a sharp corner, and a T-shaped splitter. These results may find use in the design of integrated surface-wave devices with suppressed crosstalk.

Guiding, bending, and splitting of coupled defect surface modes in a surface-wave photonic crystal

International Nuclear Information System (INIS)

Gao, Zhen; Gao, Fei; Zhang, Baile

2016-01-01

We experimentally demonstrate a type of waveguiding mechanism for coupled surface-wave defect modes in a surface-wave photonic crystal. Unlike conventional spoof surface plasmon waveguides, waveguiding of coupled surface-wave defect modes is achieved through weak coupling between tightly localized defect cavities in an otherwise gapped surface-wave photonic crystal, as a classical wave analogue of tight-binding electronic wavefunctions in solid state lattices. Wave patterns associated with the high transmission of coupled defect surface modes are directly mapped with a near-field microwave scanning probe for various structures including a straight waveguide, a sharp corner, and a T-shaped splitter. These results may find use in the design of integrated surface-wave devices with suppressed crosstalk

A novel inspection system for cosmetic defects

Science.gov (United States)

Hazra, S.; Roy, R.; Williams, D.; Aylmore, R.; Hollingdale, D.

2013-12-01

The appearance of automotive skin panels creates desirability for a product and differentiates it from the competition. Because of the importance of skin panels, considerable care is taken in minimizing defects such as the 'hollow' defect that occur around door-handle depressions. However, the inspection process is manual, subjective and time-consuming. This paper describes the development of an objective and inspection scheme for the 'hollow' defect. In this inspection process, the geometry of a panel is captured using a structured lighting system. The geometry data is subsequently analyzed by a purpose-built wavelet-based algorithm to identify the location of any defects that may be present and to estimate the perceived severity of the defects without user intervention. This paper describes and critically evaluates the behavior of this physically-based algorithm on an ideal and real geometry and compares its result to an actual audit. The results show that the algorithm is capable of objectively locating and classifying 'hollow' defects in actual panels.

Defects quantization in industrial radiographs by image processing

International Nuclear Information System (INIS)

Briand, F.Y.; Brillault, B.; Philipp, S.

1988-01-01

This paper refers to the industrial application of image processing using Non Destructive Testing by radiography. The various problems involved by the conception of a numerical tool are described. This tool intends to help radiograph experts to quantify defects and to follow up their evolution, using numerical techniques. The sequences of processings that achieve defect segmentation and quantization are detailed. They are based on the thorough knowledge of radiographs formation techniques. The process uses various methods of image analysis, including textural analysis and morphological mathematics. The interface between the final product and users will occur in an explicit language, using the terms of radiographic expertise without showing any processing details. The problem is thoroughly described: image formation, digitization, processings fitted to flaw morphology and finally product structure in progress. 12 refs [fr

Mutations in STRA6 cause a broad spectrum of malformations including anophthalmia, congenital heart defects, diaphragmatic hernia, alveolar capillary dysplasia, lung hypoplasia, and mental retardation

NARCIS (Netherlands)

Pasutto, Francesca; Sticht, Heinrich; Hammersen, Gerhard; Gillessen-Kaesbach, Gabriele; Fitzpatrick, David R.; Nuernberg, Gudrun; Brasch, Frank; Schirmer-Zimmermann, Heidemarie; Tolmie, John L.; Chitayat, David; Houge, Gunnar; Fernandez-Martinez, Lorena; Keating, Sarah; Mortier, Geert; Hennekam, Raoul C. M.; von der Wense, Axel; Slavotinek, Anne; Meinecke, Peter; Bitoun, Pierre; Becker, Christian; Nuernberg, Peter; Reis, Andre; Rauch, Anita

2007-01-01

We observed two unrelated consanguineous families with malformation syndromes sharing anophthalmia and distinct eyebrows as common signs, but differing for alveolar capillary dysplasia or complex congenital heart defect in one and diaphragmatic hernia in the other family. Homozygosity mapping

A tungsten-rhenium interatomic potential for point defect studies

Science.gov (United States)

Setyawan, Wahyu; Gao, Ning; Kurtz, Richard J.

2018-05-01

A tungsten-rhenium (W-Re) classical interatomic potential is developed within the embedded atom method interaction framework. A force-matching method is employed to fit the potential to ab initio forces, energies, and stresses. Simulated annealing is combined with the conjugate gradient technique to search for an optimum potential from over 1000 initial trial sets. The potential is designed for studying point defects in W-Re systems. It gives good predictions of the formation energies of Re defects in W and the binding energies of W self-interstitial clusters with Re. The potential is further evaluated for describing the formation energy of structures in the σ and χ intermetallic phases. The predicted convex-hulls of formation energy are in excellent agreement with ab initio data. In pure Re, the potential can reproduce the formation energies of vacancies and self-interstitial defects sufficiently accurately and gives the correct ground state self-interstitial configuration. Furthermore, by including liquid structures in the fit, the potential yields a Re melting temperature (3130 K) that is close to the experimental value (3459 K).

Peculiarities of radiation defect formation and annealing in n-Si due to their interaction with each other and defect clusters

International Nuclear Information System (INIS)

Lugakov, P.F.; Lukyanitsa, V.V.

1984-01-01

Rearrangement processes proceeding during annealing (T/sub a/ = 50 to 500 0 C) of radiation defects in 60 Co γ-irradiated (T/sub irr/ 0 C) n-Si crystals (rho = 100 to 600 Ωcm) grown by the vacuum float-zone technique are studied. The temperature dependences of the Hall coefficient are measured. The results obtained are interpreted taking into account the interaction during annealing of vacancy-type defects (E-centres, divacancies) with each other and interstitial radiation defects (C/sub i/-C/sub s/ complexes, interstitial carbon C/sub i/). Phosphorus-two vacancies complexes, stable to T/sub a/ >= 500 0 C, are shown to be formed as a result of rearrangements and interaction of E-centres between themselves. The character of interaction of vacancy defects with interstitial ones is found to change significantly in the presence of defect clusters in the bulk of the crystal which are formed under heat treatment (T = 800 0 C, two hours) of the samples preliminary irradiated with fast neutrons (flux PHI/sub n/ = 1x10 14 to 1x10 16 cm -2 ). The peculiarities of radiation defects annealing observed in this case are explained taking into account the influence of defect clusters on the migration processes of mobile defects. Nature of radiation defects being formed at various stages of annealing is discussed. (author)

Pullout Performances of Grouted Rockbolt Systems with Bond Defects

Science.gov (United States)

Xu, Chang; Li, Zihan; Wang, Shanyong; Wang, Shuren; Fu, Lei; Tang, Chunan

2018-03-01

This paper presents a numerical study on the pullout behaviour of fully grouted rockbolts with bond defects. The cohesive zone model (CZM) is adopted to model the bond-slip behaviour between the rockbolt and grout material. Tensile tests were also conducted to validate the numerical model. The results indicate that the defect length can obviously influence the load and stress distributions along the rockbolt as well as the load-displacement response of the grouted system. Moreover, a plateau in the stress distribution forms due to the bond defect. The linear limit and peak load of the load-displacement response decrease as the defect length increases. A bond defect located closer to the loaded end leads to a longer nonlinear stage in the load-displacement response. However, the peak loads measured from the specimens made with various defect locations are almost approximately the same. The peak load for a specimen with the defects equally spaced along the bolt is higher than that for a specimen with defects concentrated in a certain zone, even with the same total defect length. Therefore, the dispersed pattern of bond defects would be much safer than the concentrated pattern. For the specimen with dispersed defects, the peak load increases with an increase in the defect spacing, even if the total defect length is the same. The peak load for a grouted rockbolt system with defects increases with an increases in the bolt diameter. This work leads to a better understanding of the load transfer mechanism for grouted rockbolt systems with bond defects, and paves the way towards developing a general evaluation method for damaged rockbolt grouted systems.

Self-Reported Health Experiences of Children Living with Congenital Heart Defects: Including Patient-Reported Outcomes in a National Cohort Study.

Science.gov (United States)

Knowles, Rachel Louise; Tadic, Valerija; Hogan, Ailbhe; Bull, Catherine; Rahi, Jugnoo Sangeeta; Dezateux, Carol

2016-01-01

Understanding children's views about living with congenital heart defects (CHDs) is fundamental to supporting their successful participation in daily life, school and peer relationships. As an adjunct to a health and quality of life outcomes questionnaire, we asked school-age children who survived infant heart procedures to describe their experiences of living with CHDs. In a UK-wide cohort study, children aged 10 to 14 years with CHDs self-completed postal questionnaires that included an open question about having a 'heart problem'. We compared the characteristics of children with more and less severe cardiac diagnoses and, through collaborative inductive content analysis, investigated the subjective experiences and coping strategies described by children in both clinical severity groups. Text and/or drawings were returned by 436 children (246 boys [56%], mean age 12.1 years [SD 1.0; range 10-14]); 313 had less severe (LS) and 123 more severe (MS) cardiac diagnoses. At the most recent hospital visit, a higher proportion of the MS group were underweight (more than two standard deviations below the mean for age) or cyanosed (underweight: MS 20.0%, LS 9.9%; cyanosed: MS 26.2%, LS 3.5%). Children in the MS group described concerns about social isolation and feeling 'different', whereas children with less severe diagnoses often characterised their CHD as 'not a big thing'. Some coping strategies were common to both severity groups, including managing health information to avoid social exclusion, however only children in the LS group considered their CHD 'in the past' or experienced a sense of survivorship. Children's reported experiences were not dependent on their cardiac diagnosis, although there were clear qualitative differences by clinical severity group. Children's concerns emphasised social participation and our findings imply a need to shift the clinical focus from monitoring cardiac function to optimising participation. We highlight the potential for informing

Defect detection of wall thinning defect in pipes using lock-in photo-infrared thermography technique

Energy Technology Data Exchange (ETDEWEB)

Jang, Su Ok; Park, Jong Hyun; Choi, Tae Ho; Jung, Hyun Chul; Kim, Kyoung Suk [Chosun Univ., Gwangju (Korea, Republic of)

2008-07-01

Piping in the Nuclear Power plants (NPP) are mostly consisted of carbon steel pipe. The wall thinning defect is mainly occurred by the affect of the Flow Accelerated Corrosion (FAC) of fluid which flows in carbon steel pipes. This type of defect becomes the cause of damage or destruction of piping. Therefore, it is very important to measure defect which is existed not only on the welding partbut also on the whole field of pipe. Over the years, Infrared Thermography (IRT) has been used as a non destructive testing methods of the various kinds of materials. This technique has many merits and applied to the industrial field but has limitation to the materials. Therefore, this method was combined with lock-in technique. So IRT detection resolution has been progressively improved using lock-in technique. In this paper, the quantitative analysis results of the location and the size of wall thinning defect that is artificially processed inside the carbon steel pipe by using IRT are obtained.

Blockage of ultrafast and directional diffusion of Li atoms on phosphorene with intrinsic defects.

Science.gov (United States)

Zhang, Ruiqi; Wu, Xiaojun; Yang, Jinlong

2016-02-21

The diffusion of Li in electrode materials is a key factor for the charging/discharging rate capacity of a Li-ion battery (LIB). Recently, two-dimensional phosphorene has been proposed as a very promising electrode material due to its ultrafast and directional lithium diffusion, as well as large energy capacity. Herein, on the basis of density functional theory, we report that intrinsic point defects, including vacancy and stone-wales defects, will block the directional ultrafast diffusion of lithium in phosphorene. On the defect-free phosphorene, diffusion of Li along the zig-zag lattice direction is 1.6 billion times faster than along the armchair lattice direction, and 260 times faster than that in graphite. After introducing intrinsic vacancy and stone-wales defect, the diffusion energy barrier of Li along the zig-zag lattice direction increases sharply to the range of 0.17-0.49 eV, which blocks the ultrafast migration of lithium along the zig-zag lattice direction. Moreover, the open circuit voltage increases with the emergence of defects, which is not suitable for anode materials. In addition, the formation energies of the defects in phosphorene are considerably lower than those in graphene and silicene sheet; therefore, it is highly important to generate defect-free phosphorene for LIB applications.

Disc defect classification for optical disc drives

NARCIS (Netherlands)

Helvoirt, van J.; Leenknegt, G.A.L.; Steinbuch, M.; Goossens, H.J.

2005-01-01

Optical disc drives are subject to various disturbances and faults. A special type of fault is the so-called disc defect. In this paper we present an approach for disc defect classification. It is based on hierarchical clustering of measured signals that are affected by disc defects. The

Defect grating modes as superimposed grating states

NARCIS (Netherlands)

van Groesen, Embrecht W.C.; Sopaheluwakan, A.; Andonowati, A.; de Ridder, R.M; de Ridder, R.M.; Altena, G; Altena, G.; Geuzebroek, D.H.; Geuzenboek, D.; Dekker, R.; Dekker, R

2003-01-01

For a symmetric grating structure with a defect, we show that a fully transmitted defect mode in the band gap can be obtained as a superposition of two steady states: an amplified and an attenuated defect state. Without scanning the whole band gap by transmission calculations, this simplifies the

Malnutrition-related early childhood exposures and enamel defects in the permanent dentition: A longitudinal study from the Bolivian Amazon.

Science.gov (United States)

Masterson, Erin E; Fitzpatrick, Annette L; Enquobahrie, Daniel A; Mancl, Lloyd A; Conde, Esther; Hujoel, Philippe P

2017-10-01

We investigated the relationship between early childhood malnutrition-related measures and subsequent enamel defects in the permanent dentition. This cohort study included 349 Amerindian adolescents (10-17 years, 52% male) from the Bolivian Amazon. Exposures included: stunted growth (height-for-age z-scores), underweight (weight-for-age z-scores), anemia (hemoglobin), acute inflammation (C-reactive protein) and parasitic infection (hookworm). We measured the occurrence (no/yes) and extent (2/3) of enamel defects. We estimated associations between childhood exposures and enamel defect measures using log-binomial and multinomial logistic regression. The prevalence of an enamel defect characterized by an orange peel texture on a large central depression on the labial surface of the central maxillary incisors was 92.3%. During childhood (1-4 years), participants had a high prevalence of stunted growth (75.2%), anemia (56.9%), acute inflammation (39.1%), and hookworm infection (49.6%). We observed associations between childhood height-for-age (OR = 0.65; P = 0.028 for >2/3 extent vs. no EH) and gastrointestinal hookworm infection (OR = 3.43; P = 0.035 for >2/3 extent vs. no defects or malnutrition-related measures in early childhood, including stunted growth and parasitic helminth infection, with the observed enamel defects. © 2017 Wiley Periodicals, Inc.

Defect engineering of ZnO

Energy Technology Data Exchange (ETDEWEB)

Weber, M.H. [Center for Materials Research and Department of Physics and Astronomy, Washington State University, Pullman, WA 99164-2711 (United States)], E-mail: m_weber@wsu.edu; Selim, F.A.; Solodovnikov, D.; Lynn, K.G. [Center for Materials Research and Department of Physics and Astronomy, Washington State University, Pullman, WA 99164-2711 (United States)

2008-10-31

The defect responsible for the transparent to red color change of nominally undoped ZnO bulk single crystals is investigated. Upon annealing in the presence of metallic Zn as reported by Halliburton et al. and also Ti and Zr a native defect forms with an energy level about 0.7 eV below the conduction band. This change is reversible upon annealing in oxygen. Optical transmission data along with positron depth profiles and annealing studies are combined to identify the defect as oxygen vacancies. Vacancy clustering occurs at about 500 deg. C if isolated zinc and oxygen vacancies. In the absence of zinc vacancies, clusters form at about 800 deg. C.

Defect engineering of ZnO

International Nuclear Information System (INIS)

Weber, M.H.; Selim, F.A.; Solodovnikov, D.; Lynn, K.G.

2008-01-01

The defect responsible for the transparent to red color change of nominally undoped ZnO bulk single crystals is investigated. Upon annealing in the presence of metallic Zn as reported by Halliburton et al. and also Ti and Zr a native defect forms with an energy level about 0.7 eV below the conduction band. This change is reversible upon annealing in oxygen. Optical transmission data along with positron depth profiles and annealing studies are combined to identify the defect as oxygen vacancies. Vacancy clustering occurs at about 500 deg. C if isolated zinc and oxygen vacancies. In the absence of zinc vacancies, clusters form at about 800 deg. C

Male-female crosstalk during pollen germination, tube growth and guidance, and double fertilization.

Science.gov (United States)

Dresselhaus, Thomas; Franklin-Tong, Noni

2013-07-01

Sperm cells of flowering plants are non-motile and thus require transportation to the egg apparatus via the pollen tube to execute double fertilization. During its journey, the pollen tube interacts with various sporophytic cell types that support its growth and guide it towards the surface of the ovule. The final steps of tube guidance and sperm delivery are controlled by the cells of the female gametophyte. During fertilization, cell-cell communication events take place to achieve and maximize reproductive success. Additional layers of crosstalk exist, including self-recognition and specialized processes to prevent self-fertilization and consequent inbreeding. In this review, we focus on intercellular communication between the pollen grain/pollen tube including the sperm cells with the various sporophytic maternal tissues and the cells of the female gametophyte. Polymorphic-secreted peptides and small proteins, especially those belonging to various subclasses of small cysteine-rich proteins (CRPs), reactive oxygen species (ROS)/NO signaling, and the second messenger Ca(2+), play center stage in most of these processes.

Grinding assembly, grinding apparatus, weld joint defect repair system, and methods

Science.gov (United States)

Larsen, Eric D.; Watkins, Arthur D.; Bitsoi, Rodney J.; Pace, David P.

2005-09-27

A grinding assembly for grinding a weld joint of a workpiece includes a grinder apparatus, a grinder apparatus includes a grinding wheel configured to grind the weld joint, a member configured to receive the grinding wheel, the member being configured to be removably attached to the grinder apparatus, and a sensor assembly configured to detect a contact between the grinding wheel and the workpiece. The grinding assembly also includes a processing circuitry in communication with the grinder apparatus and configured to control operations of the grinder apparatus, the processing circuitry configured to receive weld defect information of the weld joint from an inspection assembly to create a contour grinding profile to grind the weld joint in a predetermined shape based on the received weld defect information, and a manipulator having an end configured to carry the grinder apparatus, the manipulator further configured to operate in multiple dimensions.

Eddy current inspection of weld defects in tubing

Science.gov (United States)

Katragadda, G.; Lord, W.

1992-01-01

An approach using differential probes for the inspection of weld defects in tubing is studied. Finite element analysis is used to model the weld regions and defects. Impedance plane signals are predicted for different weld defect types and compared wherever possible with signals from actual welds in tubing. Results show that detection and sizing of defects in tubing is possible using differential eddy current techniques. The phase angle of the impedance plane trajectory gives a good indication of the sizing of the crack. Data on the type of defect can be obtained from the shape of the impedance plane trajectory and the phase. Depending on the skin depth, detection of outer wall, inner wall, and subsurface defects is possible.

Infrared computations of defect Schur indices

Energy Technology Data Exchange (ETDEWEB)

Córdova, Clay [School of Natural Sciences, Institute for Advanced Study,1 Einstein Dr., Princeton, NJ (United States); Gaiotto, Davide [Perimeter Institute for Theoretical Physics,31 Caroline St., Waterloo, Ontario, N2L 2Y5 (Canada); Shao, Shu-Heng [Jefferson Physical Laboratory, Harvard University,17 Oxford St., Cambridge, MA (United States); School of Natural Sciences, Institute for Advanced Study,1 Einstein Dr., Princeton, NJ (United States)

2016-11-18

We conjecture a formula for the Schur index of four-dimensional N=2 theories in the presence of boundary conditions and/or line defects, in terms of the low-energy effective Seiberg-Witten description of the system together with massive BPS excitations. We test our proposal in a variety of examples for SU(2) gauge theories, either conformal or asymptotically free. We use the conjecture to compute these defect-enriched Schur indices for theories which lack a Lagrangian description, such as Argyres-Douglas theories. We demonstrate in various examples that line defect indices can be expressed as sums of characters of the associated two-dimensional chiral algebra and that for Argyres-Douglas theories the line defect OPE reduces in the index to the Verlinde algebra.

Holographic entanglement entropy of surface defects

International Nuclear Information System (INIS)

Gentle, Simon A.; Gutperle, Michael; Marasinou, Chrysostomos

2016-01-01

We calculate the holographic entanglement entropy in type IIB supergravity solutions that are dual to half-BPS disorder-type surface defects in N=4 supersymmetric Yang-Mills theory. The entanglement entropy is calculated for a ball-shaped region bisected by a surface defect. Using the bubbling supergravity solutions we also compute the expectation value of the defect operator. Combining our result with the previously-calculated one-point function of the stress tensor in the presence of the defect, we adapt the calculation of Lewkowycz and Maldacena http://dx.doi.org/10.1007/JHEP05(2014)025 to obtain a second expression for the entanglement entropy. Our two expressions agree up to an additional term, whose possible origin and significance is discussed.

Holographic entanglement entropy of surface defects

Energy Technology Data Exchange (ETDEWEB)

Gentle, Simon A.; Gutperle, Michael; Marasinou, Chrysostomos [Department of Physics and Astronomy, University of California,Los Angeles, CA 90095 (United States)

2016-04-12

We calculate the holographic entanglement entropy in type IIB supergravity solutions that are dual to half-BPS disorder-type surface defects in N=4 supersymmetric Yang-Mills theory. The entanglement entropy is calculated for a ball-shaped region bisected by a surface defect. Using the bubbling supergravity solutions we also compute the expectation value of the defect operator. Combining our result with the previously-calculated one-point function of the stress tensor in the presence of the defect, we adapt the calculation of Lewkowycz and Maldacena http://dx.doi.org/10.1007/JHEP05(2014)025 to obtain a second expression for the entanglement entropy. Our two expressions agree up to an additional term, whose possible origin and significance is discussed.

Anal sphincter defects and fecal incontinence 15-24 years after first delivery: a cross-sectional study.

Science.gov (United States)

Guzmán Rojas, R A; Salvesen, K Å; Volløyhaug, I

2018-05-01

To establish the prevalence of external (EAS) and internal (IAS) anal sphincter defects present 15-24 years after childbirth according to mode of delivery, and their association with development of fecal incontinence (FI). The study additionally aimed to compare the proportion of women with obstetric anal sphincter injuries (OASIS) reported at delivery with the proportion of women with sphincter defect detected on ultrasound 15-24 years later. This was a cross-sectional study including 563 women who delivered their first child between 1990 and 1997. Women responded to a validated questionnaire (Pelvic Floor Distress Inventory) in 2013-2014, from which the proportion of women with FI was recorded. Information about OASIS was obtained from the National Birth Registry. Study participants underwent four-dimensional transperineal ultrasound examination. Defect of EAS or IAS of ≥ 30° in at least four of six slices on tomographic ultrasound was considered a significant defect and was recorded. Four study groups were defined based on mode of delivery of the first child. Women who had delivered only by Cesarean section (CS) constituted the CS group. Women in the normal vaginal delivery (NVD) group had NVD of their first child and subsequent deliveries could be NVD or CS. The forceps delivery (FD) group included women who had FD, NVD or CS after FD of their first born. The vacuum delivery (VD) group included women who had VD, NVD or CS after VD of their first born. Multiple logistic regression was used to calculate adjusted odds ratios (aORs) for comparison of prevalence of an EAS defect following different modes of delivery and to test its association with FI. Fisher's exact test was used to calculate crude odds ratios (ORs) for IAS defects. Defects of EAS and IAS were found after NVD (n = 201) in 10% and 1% of cases, respectively, after FD (n = 144) in 32% and 7% of cases and after VD (n = 120) in 15% and 4% of cases. No defects were found after CS (n�

Insight into point defects and impurities in titanium from first principles

Science.gov (United States)

Nayak, Sanjeev K.; Hung, Cain J.; Sharma, Vinit; Alpay, S. Pamir; Dongare, Avinash M.; Brindley, William J.; Hebert, Rainer J.

2018-03-01

Titanium alloys find extensive use in the aerospace and biomedical industries due to a unique combination of strength, density, and corrosion resistance. Decades of mostly experimental research has led to a large body of knowledge of the processing-microstructure-properties linkages. But much of the existing understanding of point defects that play a significant role in the mechanical properties of titanium is based on semi-empirical rules. In this work, we present the results of a detailed self-consistent first-principles study that was developed to determine formation energies of intrinsic point defects including vacancies, self-interstitials, and extrinsic point defects, such as, interstitial and substitutional impurities/dopants. We find that most elements, regardless of size, prefer substitutional positions, but highly electronegative elements, such as C, N, O, F, S, and Cl, some of which are common impurities in Ti, occupy interstitial positions.

Phosphorous–vacancy–oxygen defects in silicon

KAUST Repository

Wang, Hao

2013-07-30

Electronic structure calculations employing the hybrid functional approach are used to gain fundamental insight in the interaction of phosphorous with oxygen interstitials and vacancies in silicon. It recently has been proposed, based on a binding energy analysis, that phosphorous–vacancy–oxygen defects may form. In the present study we investigate the stability of this defect as a function of the Fermi energy for the possible charge states. Spin polarization is found to be essential for the charge neutral defect.

Loop Growth and Point-Defect Profiles during HVEM Irradiation

DEFF Research Database (Denmark)

Leffers, Torben; Singh, Bachu Narain

1979-01-01

The point-defect profile in a thin foil is included in the model for the growth of dislocation loops during HVEM irradiation suggested by Kiritani, Yoshida, Takata, and Maehara, and the possible effect of divacancies is discussed. It is found that there is a fairly wide transition range between...

An Mcm10 Mutant Defective in ssDNA Binding Shows Defects in DNA Replication Initiation.

Science.gov (United States)

Perez-Arnaiz, Patricia; Kaplan, Daniel L

2016-11-20

Mcm10 is an essential protein that functions to initiate DNA replication after the formation of the replication fork helicase. In this manuscript, we identified a budding yeast Mcm10 mutant (Mcm10-m2,3,4) that is defective in DNA binding in vitro. Moreover, this Mcm10-m2,3,4 mutant does not stimulate the phosphorylation of Mcm2 by Dbf4-dependent kinase (DDK) in vitro. When we expressed wild-type levels of mcm10-m2,3,4 in budding yeast cells, we observed a severe growth defect and a substantially decreased DNA replication. We also observed a substantially reduced replication protein A- chromatin immunoprecipitation signal at origins of replication, reduced levels of DDK-phosphorylated Mcm2, and diminished Go, Ichi, Ni, and San (GINS) association with Mcm2-7 in vivo. mcm5-bob1 bypasses the growth defect conferred by DDK-phosphodead Mcm2 in budding yeast. However, the growth defect observed by expressing mcm10-m2,3,4 is not bypassed by the mcm5-bob1 mutation. Furthermore, origin melting and GINS association with Mcm2-7 are substantially decreased for cells expressing mcm10-m2,3,4 in the mcm5-bob1 background. Thus, the origin melting and GINS-Mcm2-7 interaction defects we observed for mcm10-m2,3,4 are not explained by decreased Mcm2 phosphorylation by DDK, since the defects persist in an mcm5-bob1 background. These data suggest that DNA binding by Mcm10 is essential for the initiation of DNA replication. Copyright © 2016 Elsevier Ltd. All rights reserved.

Reconstruction of mandibular defects using nonvascularized autogenous bone graft in Nigerians

Directory of Open Access Journals (Sweden)

Kizito Chioma Ndukwe

2014-01-01

Full Text Available Objectives: The aim of this study is to evaluate the success rate and complications of mandibular reconstruction with nonvascularized bone graft in Ile-Ife, Nigeria. Patients and Methods: A total of 25 patients who underwent reconstruction of mandibular discontinuity defects between January 2003 and February 2012, at the Obafemi Awolowo University Teaching Hospitals Complex, Ile-Ife constituted the study sample. Relevant information was retrieved from the patients′ records. This information include patients′ demographics (age and sex as well as the type of mandibular defect, cause of the defect, type of mandibular resection done, source of the bone graft used, and the method of graft immobilization. Morbidity associated with the graft procedures were assessed by retrieving information on graft failures, length of hospital stay following surgery, rehabilitation device used and associated graft donor and recipient site complications. Result: There were 12 males and 13 females with a male:female ratio was 1:1.1. The age of the patients ranged from 13 to 73 years with a mean age for males 32.7 ± standard deviation (SD 12.9 and for females 35.0 ± SD 17.1. Jaw defect was caused by resection for tumours and other jaw pathologies in 92% of cases. Complete symphyseal involvement defect was the most common defect recorded 11 (44%. Reconstruction with nonvascularized rib graft accounted for 68% of cases while iliac crest graft was used in 32% of the patients. Successful take of the grafts was recorded in 22 patients while three cases failed. Wound dehiscence (two patients and postoperative wound infection (eight patients were the most common complications recorded. Conclusion: The use of nonvascularized graft is still relevant in the reconstruction of large mandibular defects caused by surgical ablation of benign conditions in Nigerians. Precise surgical planning and execution, extended antibiotic therapy, and meticulous postoperative care

Lumber defect detection by ultrasonics

Science.gov (United States)

K. A. McDonald

1978-01-01

Ultrasonics, the technology of high-frequency sound, has been developed as a viable means for locating most defects In lumber for use in digital form in decision-making computers. Ultrasonics has the potential for locating surface and internal defects in lumber of all species, green or dry, and rough sawn or surfaced.

Angiographic differentiation of type of ventricular septal defects

International Nuclear Information System (INIS)

Cheon, Mal Soon; Park, Hee Young; Kim, Yang Sook

1989-01-01

Defects of the ventricular septum are the commonest type of congenital cardiac malformations. A classification with axial angiography of the subtypes of ventricular septal defects is proposed on the study of 126 patients with defects of the ventricular septum. The results were as follows: 1. The incidence of the ventricular septal defects was 39.6% of congenital heart malformation. 2. The sex distribution of cases were 70 males and 56 females, the age ranged from 13 months to 26 years. 3. Angiographic features seen by axial angiography were as follows: a. Perimembranous defects as seen on long axial view of left ventriculogram were in continuity wity aortic valve. The relation of the defect to the tricuspid valve allows distinction of the extension of the preimembranous defect toward inlet, trabecular, or infundibular zones. This relation was determined angiographically, using the course of the contrast medium from the left ventricle through the ventricular septal defect, opacifying the right ventricle. In inlet excavation, the shunted blood opacified the recess between septal leaflet of tricuspid valve and interventricular septum in early phase, in infundibular excavation, opacified the recess between anterior leaflet of tricuspid valve and anterior free wall of right ventricle and in trabecular excavation, the shunted blood traversed anterior portion of tricuspid valve ring, opacified trabecular portion of right ventricle. b. Muscular defects were separated from the semilunar and atrioventricular valves. c, Subarterial defects were related to both semilunar valves, and they were best demonstrated on the elongated right anterior oblique view of the left ventriculogram. d. Total infundibular defects were profiled in right anterior oblique 30 and long axial view, subaortic in location in both views

A large-scale molecular dynamics study of the divacancy defect in graphene

International Nuclear Information System (INIS)

Leyssale, Jean-Marc; Vignoles, Gerard L.

2014-01-01

We report on the dynamical behavior of single divacancy defects in large graphene sheets as studied by extensive classical molecular dynamics (MD) simulations at high temperatures and static calculations. In the first part of the paper, the ability of the used interatomic potential to properly render the stability and dynamics (energy barriers) of such defects is validated against electronic structure calculations from the literature. Then, results from MD simulations are presented. In agreement with recent TEM studies, some mobility is observed through a series of Stone-Wales-like bond rotations involving the 5-8-5, 555-777, and 5555-6-7777 reconstructions. Although these three structures are by far the most probable structures of the DV defect, not less than 18 other full reconstructions, including the experimentally observed 55-66-77 defect, were occasionally observed in the ∼1.5 μs of MD trajectories analyzed in this work. Most of these additional reconstructions have moderate formation energies and can be formed by a bond rotation mechanism from one of the aforementioned structures, with a lower activation energy than the one required to form a Stone-Wales defect in graphene. Therefore their future experimental observation is highly probable. The results presented here also suggest that the barrier to a conventional Stone-Wales transformation (the formation of two pentagon/heptagon pairs from four hexagons) can be significantly reduced in the vicinity of an existing defect, strengthening a recently proposed melting mechanism for graphene based on the aggregation of Stone-Wales defects. From a structural point of view, in addition to pentagons, heptagons, and octagons, these new DV reconstructions can also contain four- and nine-member rings and show a particularly large spatial extent of up to 13 rings (42 atoms) against three (14 atoms) for the original 5-8-5 defect. (authors)

Stringy models of modified gravity: space-time defects and structure formation

International Nuclear Information System (INIS)

Mavromatos, Nick E.; Sakellariadou, Mairi; Yusaf, Muhammad Furqaan

2013-01-01

Starting from microscopic models of space-time foam, based on brane universes propagating in bulk space-times populated by D0-brane defects (''D-particles''), we arrive at effective actions used by a low-energy observer on the brane world to describe his/her observations of the Universe. These actions include, apart from the metric tensor field, also scalar (dilaton) and vector fields, the latter describing the interactions of low-energy matter on the brane world with the recoiling point-like space-time defect (D-particle). The vector field is proportional to the recoil velocity of the D-particle and as such it satisfies a certain constraint. The vector breaks locally Lorentz invariance, which however is assumed to be conserved on average in a space-time foam situation, involving the interaction of matter with populations of D-particle defects. In this paper we clarify the role of fluctuations of the vector field on structure formation and galactic growth. In particular we demonstrate that, already at the end of the radiation era, the (constrained) vector field associated with the recoil of the defects provides the seeds for a growing mode in the evolution of the Universe. Such a growing mode survives during the matter dominated era, provided the variance of the D-particle recoil velocities on the brane is larger than a critical value. We note that in this model, as a result of specific properties of D-brane dynamics in the bulk, there is no issue of overclosing the brane Universe for large defect densities. Thus, in these models, the presence of defects may be associated with large-structure formation. Although our string inspired models do have (conventional, from a particle physics point of view) dark matter components, nevertheless it is interesting that the role of ''extra'' dark matter is also provided by the population of massive defects. This is consistent with the weakly interacting character of the D-particle defects, which predominantly interact only

The Boomerang-shaped Pectoralis Major Musculocutaneous Flap for Reconstruction of Circular Defect of Cervical Skin

Directory of Open Access Journals (Sweden)

Shuchi Azuma, MD

2017-11-01

Full Text Available Summary:. We report on a patient with a recurrence of oral cancer involving a cervical lymph node. The patient’s postexcision cervical skin defect was nearly circular in shape, and the size was about 12 cm in diameter. The defect was successfully reconstructed with a boomerang-shaped pectoralis major musculocutaneous flap whose skin paddle included multiple intercostal perforators of the internal mammary vessels. This flap design is effective for reconstructing an extensive neck skin defect and enables primary closure of the donor site with minimal deformity.

Defect Chemistry of Oxides for Energy Applications.

Science.gov (United States)

Schweke, Danielle; Mordehovitz, Yuval; Halabi, Mahdi; Shelly, Lee; Hayun, Shmuel

2018-05-31

Oxides are widely used for energy applications, as solid electrolytes in various solid oxide fuel cell devices or as catalysts (often associated with noble metal particles) for numerous reactions involving oxidation or reduction. Defects are the major factors governing the efficiency of a given oxide for the above applications. In this paper, the common defects in oxide systems and external factors influencing the defect concentration and distribution are presented, with special emphasis on ceria (CeO 2 ) based materials. It is shown that the behavior of a variety of oxide systems with respect to properties relevant for energy applications (conductivity and catalytic activity) can be rationalized by general considerations about the type and concentration of defects in the specific system. A new method based on transmission electron microscopy (TEM), recently reported by the authors for mapping space charge defects and measuring space charge potentials, is shown to be of potential importance for understanding conductivity mechanisms in oxides. The influence of defects on gas-surface reactions is exemplified on the interaction of CO 2 and H 2 O with ceria, by correlating between the defect distribution in the material and its adsorption capacity or splitting efficiency. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Heterogeneous rates for birth defects in Latin America: hints on causality.

Science.gov (United States)

Lopez-Camelo, J S; Orioli, I M

1996-01-01

The aim of this work was to disclose risk factors associated with birth defects which were heterogeneously distributed in the different geographic regions sampled by the Latin American Collaborative Study of Congenital Malformations (ECLAMC). The material included 2,159,065 hospital births, delivered in the 1967-1989 period in 24 geographic regions of Latin America. Birth defect types with 50 case-control pairs or more were analyzed. A risk factor was defined as that available variable with differential geographic rates, correlated with those of a given birth defect type. Identified factors were tested by case-control multivariate logistic regression to confirm their role in the occurrence of the defect. Altitude and maternal acute illness during first trimester of pregnancy, named influenza, were risk factors for microtia. Prenatal drug exposure, mainly sex hormones, were connected with the occurrence of hypospadias in low frequency areas, while Native ancestry was a "protective" factor in the same regions. Acute (influenza), and chronic (epilepsy and syphilis) maternal illness during first trimester of pregnancy and gravidity higher than four were risk factors for cleft lip. The independence of these variables from maternal age suggested that low maternal socioeconomic level could explain the high birth defect order and, perhaps, syphilis in mothers. Postaxial polydactyly was associated with parental consanguinity, as well as Afro-American ancestry, suggesting genetic heterogeneity.

Gastrointestinal system malformations in children are associated with congenital heart defects.

Science.gov (United States)

Orün, Utku Arman; Bilici, Meki; Demirçeken, Fulya G; Tosun, Mahya; Ocal, Burhan; Cavuşoğlu, Yusuf Hakan; Erdoğan, Derya; Senocak, Filiz; Karademir, Selmin

2011-03-01

To determine the frequency of congenital heart defects (CHD) in children with gastrointestinal malformations (GISM) and mortality rates in patients with GISM. Two hundred and forty two consecutive children patients with GISM followed up in Pediatric Surgery Clinics of our hospital were examined for cardiovascular anomaly by the Department of Pediatric Cardiology, and the CHD incidence was investigated by examining the records of the patients retrospectively. Chi-square test was used for the statistical analysis of data. Two hundred and forty two patients with gastrointestinal system malformations were included in the study. Of 242 patients, 135 (55.8%) were male and 107 (44.2%) were female, and their age range was 0-15 years. The most frequent GISM were anorectal malformations (43.2%), atresia involving stomach, ileum or colon (21%) and esophageal atresia/tracheoesophageal fistula (18.3%). Congenital heart defects were observed in 28.5% of the participants. The most frequent defects were as follows; atrial septal defect (31 patients, 44.9%) a, ventricular septal defect (17 patients, 24.6%) and patent ductus arteriosus (5 patients, 7.2%). There was no significant difference (p>0.05) in mortality rate in patients with CHD (16.7%) and without CHD (13.3%) undergoing operations for GISM. We would like to emphasize the importance of the earliest possible cardiological evaluation of all patients with gastrointestinal system malformations.

Defect detectability of eddy current testing for underwater laser beam welding

International Nuclear Information System (INIS)

Ueno, Souichi; Kobayashi, Noriyasu; Ochiai, Makoto; Kasuya, Takashi; Yuguchi, Yasuhiro

2011-01-01

We clarified defect detectability of eddy current testing (ECT) as a surface inspection technique for underwater laser beam welding works of dissimilar metal welding (DMW) of reactor vessel nozzle. The underwater laser beam welding procedure includes groove caving as a preparation, laser beam welding in the grooves and welded surface grinding as a post treatment. Therefore groove and welded surface inspections are required in the underwater condition. The ECT is a major candidate as this inspection technique because a penetrant testing is difficult to perform in the underwater condition. Several kinds of experiments were curried out using a cross coil an ECT probe and ECT data acquisition system in order to demonstrate the ECT defect detectability. We used specimens, simulating groove and DMW materials at an RV nozzle, with electro-discharge machining (EDM) slits over it. Additionally, we performed a detection test for artificial stress corrosion cracking (SCC) defects. From these experimental results, we confirmed that an ECT was possible to detect EDM slits 0.3 mm or more in depth and artificial SCC defects 0.02 mm to 0.48 mm in depth on machined surface. Furthermore, the underwater ECT defect detectability is equivalent to that in air. We clarified an ECT is sufficiently usable as a surface inspection technique for underwater laser beam welding works. (author)

A conceptual model for the fuel oxidation of defective fuel

International Nuclear Information System (INIS)

Higgs, J.D.; Lewis, B.J.; Thompson, W.T.; He, Z.

2007-01-01

A mechanistic conceptual model has been developed to predict the fuel oxidation behaviour in operating defective fuel elements for water-cooled nuclear reactors. This theoretical work accounts for gas-phase transport and sheath reactions in the fuel-to-sheath gap to determine the local oxygen potential. An improved thermodynamic analysis has also been incorporated into the model to describe the equilibrium state of the oxidized fuel. The fuel oxidation kinetics treatment accounts for multi-phase transport including normal diffusion and thermodiffusion for interstitial oxygen migration in the solid, as well as gas-phase transport in the fuel pellet cracks. The fuel oxidation treatment is further coupled to a heat conduction equation. A numerical solution of the coupled transport equations is obtained by a finite-element technique with the FEMLAB 3.1 software package. The model is able to provide radial-axial profiles of the oxygen-to-uranium ratio and the fuel temperatures as a function of time in the defective element for a wide range of element powers and defect sizes. The model results are assessed against coulometric titration measurements of the oxygen-to-metal profile for pellet samples taken from ten spent defective elements discharged from the National Research Universal Reactor at the Chalk River Laboratories and commercial reactors

Endotracheal tube defects: Hidden causes of airway obstruction

Directory of Open Access Journals (Sweden)

Sofi Khalid

2010-01-01

Full Text Available Manufacturing defects of endotracheal tube (ETT are still encountered in anesthesia practice. Many such defects go unnoticed during routine inspection prior to their use. Such defects in ETT may lead to partial or complete airway obstruction in an intubated patient. We report a case of partial airway obstruction with a prepacked, single use, uncuffed ETT due to a manufacturing defect in the form of a plastic meniscus at the distal end of the tube. This case report highlights the significance of standard monitoring of ventilation and the role of a vigilant clinician in detecting such defects in avoiding critical events as can arise from the use of such defective ETTs. It also emphasizes the need for double checking ETTs prior to their use.

Dissociation and diffusion of hydrogen on defect-free and vacancy defective Mg (0001) surfaces: A density functional theory study

Energy Technology Data Exchange (ETDEWEB)

Han, Zongying [College of Chemical and Environmental Engineering, Shandong University of Science and Technology, Qingdao 266590 (China); Union Research Center of Fuel Cell, School of Chemical and Environmental Engineering, China University of Mining and Technology, Beijing 100083 (China); Chen, Haipeng [College of Chemical and Environmental Engineering, Shandong University of Science and Technology, Qingdao 266590 (China); College of Mechanical and Electronic Engineering, Shandong University of Science and Technology, Qingdao 266590 (China); Zhou, Shixue, E-mail: zhoushixue66@163.com [College of Chemical and Environmental Engineering, Shandong University of Science and Technology, Qingdao 266590 (China); College of Mechanical and Electronic Engineering, Shandong University of Science and Technology, Qingdao 266590 (China)

2017-02-01

Highlights: • Clarify the effect of vacancy defect on H{sub 2} dissociation on Mg (0001) surface. • Demonstrate the effects of vacancy defect on H atom diffusion. • Reveal the minimum energy diffusion path of H atom from magnesium surface into bulk. - Abstract: First-principles calculations with the density functional theory (DFT) have been carried out to study dissociation and diffusion of hydrogen on defect-free and vacancy defective Mg (0001) surfaces. Results show that energy barriers of 1.42 eV and 1.28 eV require to be overcome for H{sub 2} dissociation on defect-free and vacancy defective Mg (0001) surfaces respectively, indicating that reactivity of Mg (0001) surface is moderately increased due to vacancy defect. Besides, the existence of vacancy defect changes the preferential H atom diffusion entrance to the subsurface and reduces the diffusion energy barrier. An interesting remark is that the minimum energy diffusion path of H atom from magnesium surface into bulk is a spiral channel formed by staggered octahedral and tetrahedral interstitials. The diffusion barriers computed for H atom penetration from the surface into inner-layers are all less than 0.70 eV, which is much smaller than the activation energy for H{sub 2} dissociation on the Mg (0001) surface. This suggests that H{sub 2} dissociation is more likely than H diffusion to be rate-limiting step for magnesium hydrogenation.

Prediction of high-temperature point defect formation in TiO2 from combined ab initio and thermodynamic calculations

International Nuclear Information System (INIS)

He, J.; Behera, R.K.; Finnis, M.W.; Li, X.; Dickey, E.C.; Phillpot, S.R.; Sinnott, S.B.

2007-01-01

A computational approach that integrates ab initio electronic structure and thermodynamic calculations is used to determine point defect stability in rutile TiO 2 over a range of temperatures, oxygen partial pressures and stoichiometries. Both donors (titanium interstitials and oxygen vacancies) and acceptors (titanium vacancies) are predicted to have shallow defect transition levels in the electronic-structure calculations. The resulting defect formation energies for all possible charge states are then used in thermodynamic calculations to predict the influence of temperature and oxygen partial pressure on the relative stabilities of the point defects. Their ordering is found to be the same as temperature increases and oxygen partial pressure decreases: titanium vacancy → oxygen vacancy → titanium interstitial. The charges on these defects, however, are quite sensitive to the Fermi level. Finally, the combined formation energies of point defect complexes, including Schottky, Frenkel and anti-Frenkel defects, are predicted to limit the further formation of point defects

Vibration of carbon nanotubes with defects: order reduction methods

Science.gov (United States)

Hudson, Robert B.; Sinha, Alok

2018-03-01

Order reduction methods are widely used to reduce computational effort when calculating the impact of defects on the vibrational properties of nearly periodic structures in engineering applications, such as a gas-turbine bladed disc. However, despite obvious similarities these techniques have not yet been adapted for use in analysing atomic structures with inevitable defects. Two order reduction techniques, modal domain analysis and modified modal domain analysis, are successfully used in this paper to examine the changes in vibrational frequencies, mode shapes and mode localization caused by defects in carbon nanotubes. The defects considered are isotope defects and Stone-Wales defects, though the methods described can be extended to other defects.

Fetal Alcohol Spectrum Disorder (FASD) Associated Neural Defects: Complex Mechanisms and Potential Therapeutic Targets.

Science.gov (United States)

Muralidharan, Pooja; Sarmah, Swapnalee; Zhou, Feng C; Marrs, James A

2013-06-19

Fetal alcohol spectrum disorder (FASD), caused by prenatal alcohol exposure, can result in craniofacial dysmorphism, cognitive impairment, sensory and motor disabilities among other defects. FASD incidences are as high as 2% to 5 % children born in the US, and prevalence is higher in low socioeconomic populations. Despite various mechanisms being proposed to explain the etiology of FASD, the molecular targets of ethanol toxicity during development are unknown. Proposed mechanisms include cell death, cell signaling defects and gene expression changes. More recently, the involvement of several other molecular pathways was explored, including non-coding RNA, epigenetic changes and specific vitamin deficiencies. These various pathways may interact, producing a wide spectrum of consequences. Detailed understanding of these various pathways and their interactions will facilitate the therapeutic target identification, leading to new clinical intervention, which may reduce the incidence and severity of these highly prevalent preventable birth defects. This review discusses manifestations of alcohol exposure on the developing central nervous system, including the neural crest cells and sensory neural placodes, focusing on molecular neurodevelopmental pathways as possible therapeutic targets for prevention or protection.

Fetal Alcohol Spectrum Disorder (FASD Associated Neural Defects: Complex Mechanisms and Potential Therapeutic Targets

Directory of Open Access Journals (Sweden)

James A. Marrs

2013-06-01

Full Text Available Fetal alcohol spectrum disorder (FASD, caused by prenatal alcohol exposure, can result in craniofacial dysmorphism, cognitive impairment, sensory and motor disabilities among other defects. FASD incidences are as high as 2% to 5 % children born in the US, and prevalence is higher in low socioeconomic populations. Despite various mechanisms being proposed to explain the etiology of FASD, the molecular targets of ethanol toxicity during development are unknown. Proposed mechanisms include cell death, cell signaling defects and gene expression changes. More recently, the involvement of several other molecular pathways was explored, including non-coding RNA, epigenetic changes and specific vitamin deficiencies. These various pathways may interact, producing a wide spectrum of consequences. Detailed understanding of these various pathways and their interactions will facilitate the therapeutic target identification, leading to new clinical intervention, which may reduce the incidence and severity of these highly prevalent preventable birth defects. This review discusses manifestations of alcohol exposure on the developing central nervous system, including the neural crest cells and sensory neural placodes, focusing on molecular neurodevelopmental pathways as possible therapeutic targets for prevention or protection.

Improving the Quality of Recycled Fine Aggregate by Selective Removal of Brittle Defects

OpenAIRE

Ogawa, Hideo; Nawa, Toyoharu

2012-01-01

Crushed recycled aggregate contains particles with brittle defects such as cracks, pores, and voids. This study presents a method for improving the quality of recycled fine aggregate by selectively removing these defects. Fourteen recycled fine aggregates were manufactured by three types of processors including a jaw crusher, ball mill, and granulator. The influence of the recycled fine aggregate on the flowability and strength of the mortar was evaluated by multivariate analysis. The results...

Defect branes as Alice strings

International Nuclear Information System (INIS)

Okada, Takashi; Sakatani, Yuho

2015-01-01

There exist various defect-brane backgrounds in supergravity theories which arise as the low energy limit of string theories. These backgrounds typically have non-trivial monodromies, and if we move a charged probe around the center of a defect, its charge will be changed by the action of the monodromy. During the process, the charge conservation law seems to be violated. In this paper, to resolve this puzzle, we examine a dynamics of the charge changing process and show that the missing charge of the probe is transferred to the background. We then explicitly construct the resultant background after the charge transfer process by utilizing dualities. This background has the same monodromy as the original defect brane, but has an additional charge which does not have any localized source. In the literature, such a charge without localized source is known to appear in the presence of Alice strings. We argue that defect branes can in fact be regarded as a realization of Alice strings in string theory and examine the charge transfer process from that perspective.