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Sample records for cylinders dna unwinding

  1. DNA binding of dinuclear iron(II) metallosupramolecular cylinders. DNA unwinding and sequence preference

    Czech Academy of Sciences Publication Activity Database

    Malina, Jaroslav; Hannon, M.J.; Brabec, Viktor

    2008-01-01

    Roč. 36, č. 11 (2008), s. 3630-3638 ISSN 0305-1048 R&D Projects: GA AV ČR(CZ) KJB400040601; GA AV ČR(CZ) 1QS500040581; GA AV ČR(CZ) KAN200200651; GA MŠk(CZ) LC06030; GA MZd(CZ) NR8562 Grant - others:GA AV ČR(CZ) IAA400040803; GA MŠk(CZ) ME08017 Program:IA; ME Institutional research plan: CEZ:AV0Z50040507; CEZ:AV0Z50040702 Keywords : supramolecular chemistry * enantiomeric DNA binding * metallosupramolecular cylinder Subject RIV: AQ - Safety, Health Protection, Human - Machine Impact factor: 6.878, year: 2008

  2. Interaction of dinuclear ruthenium(II) supramolecular cylinders with DNA: sequence-specific binding, unwinding, and photocleavage

    Czech Academy of Sciences Publication Activity Database

    Malina, Jaroslav; Hannon, M.J.; Brabec, Viktor

    2008-01-01

    Roč. 14, - (2008), s. 10408-10414 ISSN 0947-6539 R&D Projects: GA AV ČR(CZ) KJB400040601; GA AV ČR(CZ) IAA400040803; GA AV ČR(CZ) 1QS500040581; GA AV ČR(CZ) KAN200200651; GA MŠk(CZ) LC06030; GA MŠk(CZ) ME08017; GA MZd(CZ) NR8562 Institutional research plan: CEZ:AV0Z50040507; CEZ:AV0Z50040702 Keywords : DNA unwinding and photocleavage * ruthenium * supramolecular chemistry Subject RIV: AQ - Safety, Health Protection, Human - Machine Impact factor: 5.454, year: 2008

  3. Putting two heads together to unwind DNA.

    Science.gov (United States)

    Takara, Thomas J; Bell, Stephen P

    2009-11-13

    The loading of replicative helicases onto DNA is tightly regulated in all organisms, yet the molecular mechanisms for this event remain poorly defined. Remus et al. (2009) provide important insights into helicase loading in eukaryotes, showing that the Mcm2-7 replicative helicase encircles double-stranded DNA as head-to-head double hexamers.

  4. DNA unwinding assay using streptavidin-bound oligonucleotides

    Directory of Open Access Journals (Sweden)

    Kelman Zvi

    2006-11-01

    Full Text Available Abstract Background Helicases play essential roles in many cellular processes including replication, transcription and translation. Most helicases translocate along one strand of the duplex while displacing the complementary strand (of either DNA or RNA. Thus, helicases have directionality. They move along nucleic acids in either the 3'→ 5' or 5'→ 3' direction. The directionality of helicases with low activity or of those that cannot initiate duplex unwinding from a substrate that contains only one single-stranded overhang region is difficult to determine. Results An improved assay to determine helicase directionality was developed that uses a substrate containing biotinylated oligonucleotides. As a proof of concept, it was shown that the substrates substantially improve helicase activity and directionality determination for several DNA helicases in comparison to more traditional substrates. In addition, a universal substrate that can be used to determine the directionality of both 3'→ 5' and 5'→ 3' helicases was developed. Conclusion It is shown here that the use of a biotin-streptavidin complex as a helicase substrate improves helicase activity and the determination of helicase directionality. The method described is simpler that the currently available techniques.

  5. Competition between the DNA unwinding and strand pairing activities of the Werner and Bloom syndrome proteins

    Directory of Open Access Journals (Sweden)

    Orren David K

    2006-01-01

    Full Text Available Abstract Background The premature aging and cancer-prone Werner and Bloom syndromes are caused by defects in the RecQ helicase enzymes WRN and BLM, respectively. Recently, both WRN and BLM (as well as several other RecQ members have been shown to possess a strand annealing activity in addition to the requisite DNA unwinding activity. Since an annealing function would appear to directly oppose the action of a helicase, we have examined in this study the dynamic equilibrium between unwinding and annealing mediated by either WRN or BLM. Results Our investigation into the competition between annealing and unwinding demonstrates that, under standard reaction conditions, WRN- or BLM-mediated annealing can partially or completely mask unwinding as measured in standard helicase assays. Several strategies were employed to suppress the annealing activity so that the actual strength of WRN- or BLM-dependent unwinding could be more accurately assessed. Interestingly, if a DNA oligomer complementary to one strand of the DNA substrate to be unwound is added during the helicase reaction, both WRN and BLM unwinding is enhanced, presumably by preventing protein-mediated re-annealing. This strategy allowed measurement of WRN-catalyzed unwinding of long (80 base pair duplex regions and fully complementary, blunt-ended duplexes, both of which were otherwise quite refractory to the helicase activity of WRN. Similarly, the addition of trap strand stimulated the ability of BLM to unwind long and blunt-ended duplexes. The stimulatory effect of the human replication protein A (hRPA, the eukaryotic single-stranded DNA binding protein on both WRN- and BLM-dependent unwinding was also re-examined in light of its possible role in preventing re-annealing. Our results show that hRPA influences the outcome of WRN and BLM helicase assays by both inhibiting re-annealing and directly promoting unwinding, with the larger contribution from the latter mechanism. Conclusion These

  6. Torsional regulation of hRPA-induced unwinding of double-stranded DNA

    NARCIS (Netherlands)

    De Vlaminck, I.; Vidic, I.; Van Loenhout, M.T.J.; Kanaar, R.; Lebbink, J.H.G.; Dekker, C.

    2010-01-01

    All cellular single-stranded (ss) DNA is rapidly bound and stabilized by single stranded DNA-binding proteins (SSBs). Replication protein A, the main eukaryotic SSB, is able to unwind double-stranded (ds) DNA by binding and stabilizing transiently forming bubbles of ssDNA. Here, we study the

  7. Anthraquinones quinizarin and danthron unwind negatively supercoiled DNA and lengthen linear DNA

    International Nuclear Information System (INIS)

    Verebová, Valéria; Adamcik, Jozef; Danko, Patrik; Podhradský, Dušan; Miškovský, Pavol; Staničová, Jana

    2014-01-01

    Highlights: • Anthraquinones quinizarin and danthron unwind negatively supercoiled DNA. • Anthraquinones quinizarin and danthron lengthen linear DNA. • Anthraquinones quinizarin and danthron possess middle binding affinity to DNA. • Anthraquinones quinizarin and danthron interact with DNA by intercalating mode. - Abstract: The intercalating drugs possess a planar aromatic chromophore unit by which they insert between DNA bases causing the distortion of classical B-DNA form. The planar tricyclic structure of anthraquinones belongs to the group of chromophore units and enables anthraquinones to bind to DNA by intercalating mode. The interactions of simple derivatives of anthraquinone, quinizarin (1,4-dihydroxyanthraquinone) and danthron (1,8-dihydroxyanthraquinone), with negatively supercoiled and linear DNA were investigated using a combination of the electrophoretic methods, fluorescence spectrophotometry and single molecule technique an atomic force microscopy. The detection of the topological change of negatively supercoiled plasmid DNA, unwinding of negatively supercoiled DNA, corresponding to appearance of DNA topoisomers with the low superhelicity and an increase of the contour length of linear DNA in the presence of quinizarin and danthron indicate the binding of both anthraquinones to DNA by intercalating mode

  8. Anthraquinones quinizarin and danthron unwind negatively supercoiled DNA and lengthen linear DNA

    Energy Technology Data Exchange (ETDEWEB)

    Verebová, Valéria [Institute of Biophysics, University of Veterinary Medicine and Pharmacy, Komenského 73, 041 81 Košice (Slovakia); Adamcik, Jozef [Food and Soft Materials Science, Institute of Food, Nutrition and Health, ETH Zurich, Schmelzbergstrasse 9, CH-8092 Zürich (Switzerland); Danko, Patrik; Podhradský, Dušan [Department of Biochemistry, Institute of Chemistry, Faculty of Sciences, P.J. Šafárik University, Moyzesova 11, 041 54 Košice (Slovakia); Miškovský, Pavol [Department of Biophysics, Faculty of Sciences, P.J. Šafárik University, Jesenná 5, 041 54 Košice (Slovakia); Center for Interdisciplinary Biosciences, Faculty of Sciences, P.J. Šafárik University, Jesenná 5, 041 54 Košice (Slovakia); Staničová, Jana, E-mail: jana.stanicova@uvlf.sk [Institute of Biophysics, University of Veterinary Medicine and Pharmacy, Komenského 73, 041 81 Košice (Slovakia)

    2014-01-31

    Highlights: • Anthraquinones quinizarin and danthron unwind negatively supercoiled DNA. • Anthraquinones quinizarin and danthron lengthen linear DNA. • Anthraquinones quinizarin and danthron possess middle binding affinity to DNA. • Anthraquinones quinizarin and danthron interact with DNA by intercalating mode. - Abstract: The intercalating drugs possess a planar aromatic chromophore unit by which they insert between DNA bases causing the distortion of classical B-DNA form. The planar tricyclic structure of anthraquinones belongs to the group of chromophore units and enables anthraquinones to bind to DNA by intercalating mode. The interactions of simple derivatives of anthraquinone, quinizarin (1,4-dihydroxyanthraquinone) and danthron (1,8-dihydroxyanthraquinone), with negatively supercoiled and linear DNA were investigated using a combination of the electrophoretic methods, fluorescence spectrophotometry and single molecule technique an atomic force microscopy. The detection of the topological change of negatively supercoiled plasmid DNA, unwinding of negatively supercoiled DNA, corresponding to appearance of DNA topoisomers with the low superhelicity and an increase of the contour length of linear DNA in the presence of quinizarin and danthron indicate the binding of both anthraquinones to DNA by intercalating mode.

  9. Coupling DNA unwinding activity with primer synthesis in the bacteriophage T4 primosome

    Science.gov (United States)

    Manosas, Maria; Spiering, Michelle M.; Zhuang, Zhihao; Benkovic, Stephen J.; Croquette, Vincent

    2009-01-01

    The unwinding and priming activities of the bacteriophage T4 primosome, which consists of a hexameric helicase (gp41) translocating 5′ to 3′ and an oligomeric primase (gp61) synthesizing primers 5′ to 3′, has been investigated on DNA hairpins manipulated by a magnetic trap. We find that the T4 primosome continuously unwinds the DNA duplex while allowing for primer synthesis through a primosome disassembly mechanism or a novel DNA looping mechanism. A fused gp61-gp41 primosome unwinds and primes DNA exclusively via the DNA looping mechanism. Other proteins within the replisome control the partitioning of these two mechanisms disfavoring primosome disassembly thereby increasing primase processivity. In contrast priming in bacteriophage T7 involves discrete pausing of the primosome and in Escherichia coli appears to be associated primarily with dissociation of the primase from the helicase. Thus nature appears to use several strategies to couple the disparate helicase and primase activities within primosomes. PMID:19838204

  10. Enzyme-catalyzed DNA unwinding: studies on Escherichia coli rep protein.

    Science.gov (United States)

    Yarranton, G T; Gefter, M L

    1979-04-01

    Replication in vitro of the replicative form (RF) I DNA of bacteriophage varphiX174 requires the phage-induced cistron A (cisA) protein, the host rep protein, DNA-binding protein, ATP, and DNA polymerase III plus replication factors. The rep protein is a single-stranded DNA-dependent ATPase. In this paper we show that varphiX174 RF I DNA cut by the cisA protein acts as a duplex DNA cofactor for the rep protein ATPase activity, provided that DNA-binding protein is present. In this latter reaction the duplex DNA is unwound by the rep protein with concomitant hydrolysis of ATP. The extents of ATP hydrolysis, DNA unwinding, and, where appropriate, DNA synthesis are proportional to the amounts of DNA-binding protein present. Two ATP molecules are hydrolyzed per base pair unwound. We propose that the obligatory requirement for the cisA protein in the unwinding of varphiX174 RF I DNA is not simply due to its endonuclease activity but rather is due to its provision of a site for the binding of the rep protein. The rep protein in the presence of DNA-binding protein, but in the absence of cisA protein, unwinds duplex DNA when one strand extends to generate a single-stranded leader region preceding the duplex. We show that rep protein translocates along the leader single strand in a 5'-to-3' direction only and then invades the duplex DNA. The rep protein shows a directional specificity for translocation and unwinding. A model is presented to explain the mechanism of DNA unwinding catalyzed by the rep protein.

  11. Structural basis for replication origin unwinding by an initiator primase of plasmid ColE2-P9: duplex DNA unwinding by a single protein.

    Science.gov (United States)

    Itou, Hiroshi; Yagura, Masaru; Shirakihara, Yasuo; Itoh, Tateo

    2015-02-06

    Duplex DNA is generally unwound by protein oligomers prior to replication. The Rep protein of plasmid ColE2-P9 (34 kDa) is an essential initiator for plasmid DNA replication. This protein binds the replication origin (Ori) in a sequence-specific manner as a monomer and unwinds DNA. Here we present the crystal structure of the DNA-binding domain of Rep (E2Rep-DBD) in complex with Ori DNA. The structure unveils the basis for Ori-specific recognition by the E2Rep-DBD and also reveals that it unwinds DNA by the concerted actions of its three contiguous structural modules. The structure also shows that the functionally unknown PriCT domain, which forms a compact module, plays a central role in DNA unwinding. The conservation of the PriCT domain in the C termini of some archaeo-eukaryotic primases indicates that it probably plays a similar role in these proteins. Thus, this is the first report providing the structural basis for the functional importance of the conserved PriCT domain and also reveals a novel mechanism for DNA unwinding by a single protein. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

  12. Structural insights into 5‧ flap DNA unwinding and incision by the human FAN1 dimer

    Science.gov (United States)

    Zhao, Qi; Xue, Xiaoyu; Longerich, Simonne; Sung, Patrick; Xiong, Yong

    2014-12-01

    Human FANCD2-associated nuclease 1 (FAN1) is a DNA structure-specific nuclease involved in the processing of DNA interstrand crosslinks (ICLs). FAN1 maintains genomic stability and prevents tissue decline in multiple organs, yet it confers ICL-induced anti-cancer drug resistance in several cancer subtypes. Here we report three crystal structures of human FAN1 in complex with a 5‧ flap DNA substrate, showing that two FAN1 molecules form a head-to-tail dimer to locate the lesion, orient the DNA and unwind a 5‧ flap for subsequent incision. Biochemical experiments further validate our model for FAN1 action, as structure-informed mutations that disrupt protein dimerization, substrate orientation or flap unwinding impair the structure-specific nuclease activity. Our work elucidates essential aspects of FAN1-DNA lesion recognition and a unique mechanism of incision. These structural insights shed light on the cellular mechanisms underlying organ degeneration protection and cancer drug resistance mediated by FAN1.

  13. DNA binding and unwinding by Hel308 helicase requires dual functions of a winged helix domain.

    Science.gov (United States)

    Northall, Sarah J; Buckley, Ryan; Jones, Nathan; Penedo, J Carlos; Soultanas, Panos; Bolt, Edward L

    2017-09-01

    Hel308 helicases promote genome stability linked to DNA replication in archaea, and have homologues in metazoans. In the crystal structure of archaeal Hel308 bound to a tailed DNA duplex, core helicase domains encircle single-stranded DNA (ssDNA) in a "ratchet" for directional translocation. A winged helix domain (WHD) is also present, but its function is mysterious. We investigated the WHD in full-length Hel308, identifying that mutations in a solvent exposed α-helix resulted in reduced DNA binding and unwinding activities. When isolated from the rest of Hel308, the WHD protein alone bound to duplex DNA but not ssDNA, and DNA binding by WHD protein was abolished by the same mutations as were analyzed in full-length Hel308. Isolated WHD from a human Hel308 homologue (HelQ) also bound to duplex DNA. By disrupting the interface between the Hel308 WHD and a RecA-like domain, a topology typical of Ski2 helicases, we show that this is crucial for ATPase and helicase activities. The data suggest a model in which the WHD promotes activity of Hel308 directly, through binding to duplex DNA that is distinct from ssDNA binding by core helicase, and indirectly through interaction with the RecA-like domain. We propose how the WHD may contribute to ssDNA translocation, resulting in DNA helicase activity or in removal of other DNA bound proteins by "reeling" ssDNA. Copyright © 2017 Elsevier B.V. All rights reserved.

  14. Mycobacterium smegmatis Lhr Is a DNA-dependent ATPase and a 3'-to-5' DNA translocase and helicase that prefers to unwind 3'-tailed RNA:DNA hybrids.

    Science.gov (United States)

    Ordonez, Heather; Shuman, Stewart

    2013-05-17

    We are interested in the distinctive roster of helicases of Mycobacterium, a genus of the phylum Actinobacteria that includes the human pathogen Mycobacterium tuberculosis and its avirulent relative Mycobacterium smegmatis. Here, we identify and characterize M. smegmatis Lhr as the exemplar of a novel clade of superfamily II helicases, by virtue of its biochemical specificities and signature domain organization. Lhr is a 1507-amino acid monomeric nucleic acid-dependent ATPase that uses the energy of ATP hydrolysis to drive unidirectional 3'-to-5' translocation along single strand DNA and to unwind duplexes en route. The ATPase is more active in the presence of calcium than magnesium. ATP hydrolysis is triggered by either single strand DNA or single strand RNA, yet the apparent affinity for a DNA activator is 11-fold higher than for an RNA strand of identical size and nucleobase sequence. Lhr is 8-fold better at unwinding an RNA:DNA hybrid than it is at displacing a DNA:DNA duplex of identical nucleobase sequence. The truncated derivative Lhr-(1-856) is an autonomous ATPase, 3'-to-5' translocase, and RNA:DNA helicase. Lhr-(1-856) is 100-fold better RNA:DNA helicase than DNA:DNA helicase. Lhr homologs are found in bacteria representing eight different phyla, being especially prevalent in Actinobacteria (including M. tuberculosis) and Proteobacteria (including Escherichia coli).

  15. Mycobacterium tuberculosis DinG is a structure-specific helicase that unwinds G4 DNA: implications for targeting G4 DNA as a novel therapeutic approach.

    Science.gov (United States)

    Thakur, Roshan Singh; Desingu, Ambika; Basavaraju, Shivakumar; Subramanya, Shreelakshmi; Rao, Desirazu N; Nagaraju, Ganesh

    2014-09-05

    The significance of G-quadruplexes and the helicases that resolve G4 structures in prokaryotes is poorly understood. The Mycobacterium tuberculosis genome is GC-rich and contains >10,000 sequences that have the potential to form G4 structures. In Escherichia coli, RecQ helicase unwinds G4 structures. However, RecQ is absent in M. tuberculosis, and the helicase that participates in G4 resolution in M. tuberculosis is obscure. Here, we show that M. tuberculosis DinG (MtDinG) exhibits high affinity for ssDNA and ssDNA translocation with a 5' → 3' polarity. Interestingly, MtDinG unwinds overhangs, flap structures, and forked duplexes but fails to unwind linear duplex DNA. Our data with DNase I footprinting provide mechanistic insights and suggest that MtDinG is a 5' → 3' polarity helicase. Notably, in contrast to E. coli DinG, MtDinG catalyzes unwinding of replication fork and Holliday junction structures. Strikingly, we find that MtDinG resolves intermolecular G4 structures. These data suggest that MtDinG is a multifunctional structure-specific helicase that unwinds model structures of DNA replication, repair, and recombination as well as G4 structures. We finally demonstrate that promoter sequences of M. tuberculosis PE_PGRS2, mce1R, and moeB1 genes contain G4 structures, implying that G4 structures may regulate gene expression in M. tuberculosis. We discuss these data and implicate targeting G4 structures and DinG helicase in M. tuberculosis could be a novel therapeutic strategy for culminating the infection with this pathogen. © 2014 by The American Society for Biochemistry and Molecular Biology, Inc.

  16. Cryo-EM Structure of a Relaxase Reveals the Molecular Basis of DNA Unwinding during Bacterial Conjugation.

    Science.gov (United States)

    Ilangovan, Aravindan; Kay, Christopher W M; Roier, Sandro; El Mkami, Hassane; Salvadori, Enrico; Zechner, Ellen L; Zanetti, Giulia; Waksman, Gabriel

    2017-05-04

    Relaxases play essential roles in conjugation, the main process by which bacteria exchange genetic material, notably antibiotic resistance genes. They are bifunctional enzymes containing a trans-esterase activity, which is responsible for nicking the DNA strand to be transferred and for covalent attachment to the resulting 5'-phosphate end, and a helicase activity, which is responsible for unwinding the DNA while it is being transported to a recipient cell. Here we show that these two activities are carried out by two conformers that can both load simultaneously on the origin of transfer DNA. We solve the structure of one of these conformers by cryo electron microscopy to near-atomic resolution, elucidating the molecular basis of helicase function by relaxases and revealing insights into the mechanistic events taking place in the cell prior to substrate transport during conjugation. Copyright © 2017 The Author(s). Published by Elsevier Inc. All rights reserved.

  17. Mitochondrial DNA Unwinding Enzyme Required for Liver Regeneration | Center for Cancer Research

    Science.gov (United States)

    The liver has an exceptional capacity to proliferate. This ability allows the liver to regenerate its mass after partial surgical removal or injury and is the key to successful partial liver transplants. Liver cells, called hepatocytes, are packed with mitochondria, and regulating mitochondrial DNA (mtDNA) copy number is crucial to mitochondrial function, including energy production, during proliferation. Yves Pommier, M.D., Ph.D., of CCR’s Developmental Therapeutics Branch, and his colleagues recently showed that the vertebrate mitochondrial topoisomerase, Top1mt, was critical in maintaining mitochondrial function in the heart after doxorubicin-induced damage. The group wondered whether Top1mt might play a similar role in liver regeneration.

  18. Double-check probing of DNA bending and unwinding by XPA-RPA: an architectural function in DNA repair

    Czech Academy of Sciences Publication Activity Database

    Missura, M.; Buterin, T.; Hindges, R.; Hübscher, U.; Kašpárková, Jana; Brabec, Viktor; Naegeli, H.

    2001-01-01

    Roč. 20, č. 13 (2001), s. 3554-3564 ISSN 0261-4189 Institutional research plan: CEZ:AV0Z5004920 Keywords : damage recognition * DNA repair * xeroderma pigmentosum Subject RIV: BO - Biophysics Impact factor: 12.450, year: 2001

  19. DNA unwinding by ASCC3 helicase is coupled to ALKBH3 dependent DNA alkylation repair and cancer cell proliferation

    Science.gov (United States)

    Dango, Sebastian; Mosammaparast, Nima; Sowa, Mathew E.; Xiong, Li-Jun; Wu, Feizhen; Park, Keyjung; Rubin, Mark; Gygi, Steve; Harper, J. Wade; Shi, Yang

    2011-01-01

    Summary Demethylation by the AlkB dioxygenases represents an important mechanism for repair of N-alkylated nucleotides. However, little is known about their functions in mammalian cells. We report the purification of the ALKBH3 complex and demonstrate its association with the Activating Signal Co-integrator Complex (ASCC). ALKBH3 is overexpressed in various cancers, and both ALKBH3 and ASCC are important for alkylation damage resistance in these tumor cell lines. ASCC3, the largest subunit of ASCC, encodes a 3′-5′ DNA helicase, whose activity is crucial for the generation of single-stranded DNA upon which ALKBH3 preferentially functions for dealkylation. In cell lines that are dependent on ALKBH3 and ASCC3 for alkylation damage resistance, loss of ALKBH3 or ASCC3 leads to increased 3-methylcytosine and reduced cell proliferation, which correlates with pH2A.X and 53BP1 foci formation. Our data provide a molecular mechanism by which ALKBH3 collaborates with ASCC to maintain genomic integrity in a cell type specific manner. PMID:22055184

  20. Unwinding after high salinity stress: Pea DNA helicase 45 over- expression in tobacco confers high salinity tolerance without affecting yield (abstract)

    International Nuclear Information System (INIS)

    Tuteja, N.

    2005-01-01

    Soil salinity is an increasing threat for agriculture and is a major factor in reducing plant productivity; therefore, it is necessary to obtain salinity-tolerant varieties. A typical characteristic of soil salinity is the induction of multiple stress- inducible genes. Some of the genes encoding osmolytes, ion channels or enzymes are able to confer salinity-tolerant phenotypes when transferred to sensitive plants. As salinity stress affects the cellular gene-expression machinery, it is evident that molecules involved in nucleic acid processing including helicases, are likely to be affected as well. DNA helicases unwind duplex DNA and are involved in replication, repair, recombination and transcription while RNA helicases unfold the secondary structures in RNA and are involved in transcription, ribosome biogenesis and translation initiation. We have earlier reported the isolation of a pea DNA helicase 45 (PDH45) that exhibits striking homology with eIF-4A (Plant J. 24:219-230,2000). Here we report that PDH45 mRNA is induced in pea seedlings in response to high salt and its over- expression driven by a constitutive CAMV-355-promoter in tobacco plants confers salinity tolerance, thus suggesting a new pathway for manipulating stress tolerance in crop plants. The T0 transgenic plants showed high-levels of PDH45 protein in normal and stress conditions, as compared to wild type (WT) plants. The T0 transgenics also showed tolerance to high salinity as tested by a leaf disc senescence assay. The T1 transgenics were able to grow to maturity and set normal viable seeds under continuous salinity stress, without any reduction in plant yield, in terms of seed weight. Measurement of Na/sup +/ ions in different parts of the plant showed higher accumulation in the old leaves and negligible in seeds of T1 transgenic lines as compared with the WT plants. The possible mechanism of salinity tolerance will be discussed. Over-expression of PDH45 provides a possible example of the

  1. Mycobacterium tuberculosis RecG binds and unwinds model DNA substrates with a preference for Holliday junctions.

    Science.gov (United States)

    Zegeye, Ephrem Debebe; Balasingham, Seetha V; Laerdahl, Jon K; Homberset, Håvard; Tønjum, Tone

    2012-08-01

    The RecG enzyme, a superfamily 2 helicase, is present in nearly all bacteria. Here we report for the first time that the recG gene is also present in the genomes of most vascular plants as well as in green algae, but is not found in other eukaryotes or archaea. The precise function of RecG is poorly understood, although ample evidence shows that it plays critical roles in DNA repair, recombination and replication. We further demonstrate that Mycobacterium tuberculosis RecG (RecG(Mtb)) DNA binding activity had a broad substrate specificity, whereas it only unwound branched-DNA substrates such as Holliday junctions (HJs), replication forks, D-loops and R-loops, with a strong preference for the HJ as a helicase substrate. In addition, RecG(Mtb) preferentially bound relatively long (≥40 nt) ssDNA, exhibiting a higher affinity for the homopolymeric nucleotides poly(dT), poly(dG) and poly(dC) than for poly(dA). RecG(Mtb) helicase activity was supported by hydrolysis of ATP or dATP in the presence of Mg(2+), Mn(2+), Cu(2+) or Fe(2+). Like its Escherichia coli orthologue, RecG(Mtb) is also a strictly DNA-dependent ATPase.

  2. How charge fluctuations modulate complexation of DNA around a histone cylinder

    Science.gov (United States)

    Kim, Won Kyu; Sung, Wokyung

    2013-10-01

    It is an enigma that in a nucleosome complex, a single DNA winds around a histone protein core about 1.6-1.8 times. We find that the optimal winding can be given by the charge density fluctuations on the DNA contour due to multivalent counterions binding and unbinding in a physiological ionic background. From a model free energy of the DNA wound on the histone cylinder, where the charge fluctuations induce the intra-DNA attraction, we establish the conditions and a phase diagram for stability of the complex as a function of the salt and divalent cations concentrations.

  3. Comparison of DNA double-strand break rejoining as measured by pulsed field gel electrophoresis, neutral sucrose gradient centrifugation and non-unwinding filter elution in irradiated plateau-phase CHO cells

    International Nuclear Information System (INIS)

    Iliakis, G.; Metzger, L.; Pantelias, G.

    1991-01-01

    The initial (up to 30 min) rate of DNA double-strand break (dsb) rejoining was measured in irradiated plateau-phase CHO cells, in a set of parallel experiments using the same cell suspension, by means of non-unwinding filter elution, neutral sucrose gradient centrifugation, and two pulsed-field gel electrophoresis assays: asymmetric field inversion gel electrophoresis (AFIGE) and clamped homogeneous electric field (CHEF) gel electrophoresis. The rate of DNA dsb rejoining was compared to the rate of rejoining of chromatin breaks measured, also in the same cell population, using the technique of premature chromosome condensation (PCC). Two radiation exposures, 25 Gy and/or 50 Gy, were used and applied to the individual parts of the experiments according to the sensitivity of the assay under investigation. The results suggest all major techniques currently used for assaying rejoining of DNA dsb give similar results, and indicate that more information is required before a direct correlation between rejoining of DNA dsb and rejoining of chromatin breaks can be established. (author)

  4. Unwinding in Hopfion vortex bunches

    Science.gov (United States)

    Jäykkä, Juha; Hietarinta, Jarmo

    2009-06-01

    We investigate the behavior of parallel Faddeev-Hopf vortices under energy minimization in a system with physically relevant, but unusual boundary conditions. The homotopy classification is no longer provided by the Hopf invariant, but rather by the set of integer homotopy invariants proposed by Pontrjagin. The nature of these invariants depends on the boundary conditions. A set of tightly wound parallel vortices of the usual Hopfion structure is observed to form a bunch of intertwined vortices or unwind completely, depending on the boundary conditions.

  5. Mycobacterium smegmatis HelY Is an RNA-Activated ATPase/dATPase and 3'-to-5' Helicase That Unwinds 3'-Tailed RNA Duplexes and RNA:DNA Hybrids.

    Science.gov (United States)

    Uson, Maria Loressa; Ordonez, Heather; Shuman, Stewart

    2015-10-01

    Mycobacteria have a large and distinctive ensemble of DNA helicases that function in DNA replication, repair, and recombination. Little is known about the roster of RNA helicases in mycobacteria or their roles in RNA transactions. The 912-amino-acid Mycobacterium smegmatis HelY (MSMEG_3885) protein is a bacterial homolog of the Mtr4 and Ski2 helicases that regulate RNA 3' processing and turnover by the eukaryal exosome. Here we characterize HelY as an RNA-stimulated ATPase/dATPase and an ATP/dATP-dependent 3'-to-5' helicase. HelY requires a 3' single-strand RNA tail (a loading RNA strand) to displace the complementary strand of a tailed RNA:RNA or RNA:DNA duplex. The findings that HelY ATPase is unresponsive to a DNA polynucleotide cofactor and that HelY is unable to unwind a 3'-tailed duplex in which the loading strand is DNA distinguish HelY from other mycobacterial nucleoside triphosphatases/helicases characterized previously. The biochemical properties of HelY, which resemble those of Mtr4/Ski2, hint at a role for HelY in mycobacterial RNA catabolism. RNA helicases play crucial roles in transcription, RNA processing, and translation by virtue of their ability to alter RNA secondary structure or remodel RNA-protein interactions. In eukarya, the RNA helicases Mtr4 and Ski2 regulate RNA 3' resection by the exosome. Mycobacterium smegmatis HelY, a bacterial homolog of Mtr4/Ski2, is characterized here as a unidirectional helicase, powered by RNA-dependent ATP/dATP hydrolysis, that tracks 3' to 5' along a loading RNA strand to displace the complementary strand of a tailed RNA:RNA or RNA:DNA duplex. The biochemical properties of HelY suggest a role in bacterial RNA transactions. HelY homologs are present in pathogenic mycobacteria (e.g., M. tuberculosis and M. leprae) and are widely prevalent in Actinobacteria and Cyanobacteria but occur sporadically elsewhere in the bacterial domain. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

  6. Is inflation from unwinding fluxes IIB?

    Energy Technology Data Exchange (ETDEWEB)

    Gautason, Fridrik Freyr [Instituut voor Theoretische Fysica, K.University Leuven,Celestijnenlaan 200D, B-3001 Leuven (Belgium); Institut de Physique Théorique, Université Paris Saclay, CEA, CNRS,Orme des Merisiers, F-91191 Gif-sur-Yvette (France); Schillo, Marjorie; Riet, Thomas Van [Instituut voor Theoretische Fysica, K.University Leuven,Celestijnenlaan 200D, B-3001 Leuven (Belgium)

    2017-03-07

    In this paper we argue that the mechanism of unwinding inflation is naturally present in warped compactifications of type IIB string theory with local throats. The unwinding of flux is caused by its annihilation against branes. The resulting inflaton potential is linear with periodic modulations. We initiate an analysis of the inflationary dynamics and cosmological observables, which are highly constrained by moduli stabilization. For the simplified model of single-Kähler Calabi-Yau spaces we find that many, though not all of the consistency constraints can be satisfied. Particularly, in this simple model geometric constraints are in tension with obtaining the observed amplitude of the scalar power spectrum. However, we do find 60 efolds of inflation with a trans-Planckian field excursion which offers the hope that slightly more complicated models can lead to a fully consistent explicit construction of large field inflation of this kind.

  7. Two-state model for helicase translocation and unwinding of nucleic acids

    Science.gov (United States)

    Garai, Ashok; Chowdhury, Debashish; Betterton, M. D.

    2008-06-01

    Helicases are molecular motors that unwind double-stranded nucleic acids (dsNA), such as DNA and RNA. Typically a helicase translocates along one of the NA single strands while unwinding and uses adenosine triphosphate (ATP) hydrolysis as an energy source. Here we model a helicase motor that can switch between two states, which could represent two different points in the ATP hydrolysis cycle. Our model is an extension of the earlier Betterton-Jülicher model of helicases to incorporate switching between two states. The main predictions of the model are the speed of unwinding of the dsNA and fluctuations around the average unwinding velocity. Motivated by a recent claim that the NS3 helicase of Hepatitis C virus follows a flashing-ratchet mechanism, we have compared the experimental results for the NS3 helicase with a special limit of our model which corresponds to the flashing-ratchet scenario. Our model accounts for one key feature of the experimental data on NS3 helicase. However, contradictory observations in experiments carried out under different conditions limit the ability to compare the model to experiments.

  8. A multi-step model for facilitated unwinding of the yeast U4/U6 RNA duplex

    Science.gov (United States)

    Rodgers, Margaret L.; Didychuk, Allison L.; Butcher, Samuel E.; Brow, David A.; Hoskins, Aaron A.

    2016-01-01

    The small nuclear RNA (snRNA) components of the spliceosome undergo many conformational rearrangements during its assembly, catalytic activation and disassembly. The U4 and U6 snRNAs are incorporated into the spliceosome as a base-paired complex within the U4/U6.U5 small nuclear ribonucleoprotein (tri-snRNP). U4 and U6 are then unwound in order for U6 to pair with U2 to form the spliceosome's active site. After splicing, U2/U6 is unwound and U6 annealed to U4 to reassemble the tri-snRNP. U6 rearrangements are crucial for spliceosome formation but are poorly understood. We have used single-molecule Förster resonance energy transfer and unwinding assays to identify interactions that promote U4/U6 unwinding and have studied their impact in yeast. We find that U4/U6 is efficiently unwound using DNA oligonucleotides by coupling unwinding of U4/U6 stem II with strand invasion of stem I. Unwinding is stimulated by the U6 telestem, which transiently forms in the intact U4/U6 RNA complex. Stabilization of the telestem in vivo results in accumulation of U4/U6 di-snRNP and impairs yeast growth. Our data reveal conserved mechanisms for U4/U6 unwinding and indicate telestem dynamics are critical for tri-snRNP assembly and stability. PMID:27484481

  9. Mycobacterium smegmatis RqlH defines a novel clade of bacterial RecQ-like DNA helicases with ATP-dependent 3'-5' translocase and duplex unwinding activities.

    Science.gov (United States)

    Ordonez, Heather; Unciuleac, Mihaela; Shuman, Stewart

    2012-05-01

    The Escherichia coli RecQ DNA helicase participates in a pathway of DNA repair that operates in parallel to the recombination pathway driven by the multisubunit helicase-nuclease machine RecBCD. The model mycobacterium Mycobacterium smegmatis executes homologous recombination in the absence of its helicase-nuclease machine AdnAB, though it lacks a homolog of E. coli RecQ. Here, we identify and characterize M. smegmatis RqlH, a RecQ-like helicase with a distinctive domain structure. The 691-amino acid RqlH polypeptide consists of a RecQ-like ATPase domain (amino acids 1-346) and tetracysteine zinc-binding domain (amino acids 435-499), separated by an RqlH-specific linker. RqlH lacks the C-terminal HRDC domain found in E. coli RecQ. Rather, the RqlH C-domain resembles bacterial ComF proteins and includes a phosphoribosyltransferase-like module. We show that RqlH is a DNA-dependent ATPase/dATPase that translocates 3'-5' on single-stranded DNA and has 3'-5' helicase activity. These functions inhere to RqlH-(1-505), a monomeric motor unit comprising the ATPase, linker and zinc-binding domains. RqlH homologs are distributed widely among bacterial taxa. The mycobacteria that encode RqlH lack a classical RecQ, though many other Actinobacteria have both RqlH and RecQ. Whereas E. coli K12 encodes RecQ but lacks a homolog of RqlH, other strains of E. coli have both RqlH and RecQ.

  10. Psychosomatic complaints and unwinding of sympathoadrenal activation after work

    NARCIS (Netherlands)

    Kuiper, J.I.; van der Beek, A.J.; Meijman, T.F.

    It is well known that chronically elevated catecholamine excretion rates are associated with health problems, indicating the importance of recovery after work. In 28 male truck drivers, unwinding after work was found to be insufficient. The resulting spillover of sympathoadrenal activation, as

  11. Unwinding of a carbon nanoscroll due to high speed rotation

    Directory of Open Access Journals (Sweden)

    Hang Yin

    2015-10-01

    Full Text Available A carbon nanoscroll (CNS can be formed easily by rolling a graphene sheet around a carbon nanotube (CNT [Zhang and Li, 2010, APL, 97, 081909]. When the CNS is driven by the rotary CNT to rotate at a high speed, the attractive interaction within the CNS or between the CNS and CNT is crippled by the centrifugal force on the CNS. The unwinding of CNS is triggered when the kinetic energy increment approaches to the variation of interaction energy of the system during CNS formation. Numerical experiments also indicate that the unwinding of CNS happens earlier when the CNT has a higher rotational speed or the system is at a higher temperature.

  12. Theoretical and Semi-Empirical Methods of Designing Ribbon Unwinders.

    Science.gov (United States)

    1982-06-01

    other hand, include the effects of parameters that exist during testing but are not included in the phisical analysis. Variations in test procedures and...0297 / 191 N UNLSFIEDmos EEmmoEEImiomEE EomhEmhhEmhhhhI EhohmhmhohEEEI,mEE~hEE~EEE IfLhI L. 2 28 AL . MICROCOPY RESOLUTION TEST CHART NATIONAL BUREAU...distrbution is Lnhm d 83 06 30 046 TABLE OF CONTENTS Page 1. INTRODUCTION & SUMMARY 1 2. EXPERIMENTAL. POGRAM 2.1 Test Plan 9 2.2 Ribbon Unwinder.Assembly 9

  13. DNA Structure Specificity Conferred on a Replicative Helicase by Its Loader*

    OpenAIRE

    Gupta, Milind K.; Atkinson, John; McGlynn, Peter

    2009-01-01

    Prokaryotic and eukaryotic replicative helicases can translocate along single-stranded and double-stranded DNA, with the central cavity of these multimeric ring helicases being able to accommodate both forms of DNA. Translocation by such helicases along single-stranded DNA results in the unwinding of forked DNA by steric exclusion and appears critical in unwinding of parental strands at the replication fork, whereas translocation over double-stranded DNA has no well-defined role. We have foun...

  14. Werner helicase wings DNA binding

    OpenAIRE

    Hoadley, Kelly A.; Keck, James L.

    2010-01-01

    In this issue of Structure, Kitano et al. describe the structure of the DNA-bound winged-helix domain from the Werner helicase. This structure of a RecQ/DNA complex offers insights into the DNA unwinding mechanisms of RecQ family helicases.

  15. Genotoxicity of cadmium chloride in the marine gastropod Nerita chamaeleon using comet assay and alkaline unwinding assay.

    Science.gov (United States)

    Sarkar, Anupam; Bhagat, Jacky; Ingole, Baban S; Rao, Durga P; Markad, Vijaykumar L

    2015-02-01

    This paper presents an evaluation of the genotoxic effects of cadmium chloride (CdCl2 ) on marine gastropod, Nerita chamaeleon following the technique of comet assay and the DNA alkaline unwinding assay (DAUA). In this study, the extent of DNA damage in gill cells of N. chamaeleon was measured after in vivo exposure to four different concentrations (10, 25, 50, and 75 µg/L) of CdCl2 . In vitro exposure of hydrogen peroxide (H2 O2 ; 1, 10, 25, and 50 µM) of the gill cells showed a significant increase in the percentage tail DNA, Olive tail moment, and tail length (TL). Significant changes in percentage tail DNA by CdCl2 exposure were observed in all exposed groups of snails with respect to those in control. Exposure to 75 µg/L of CdCl2 produced significant decrease in DNA integrity as measured by DAUA at all duration with respect to control. In vivo exposure to different concentrations of CdCl2 (10, 25, 50, and 75 µg/L) to N. chamaeleon showed considerable increase in DNA damage as observed by both alkaline comet assay and the DAUA. The extent of DNA damage in marine gastropods determined by the application of alkaline comet assay and DAUA clearly indicated the genotoxic responses of marine gastropod, N. chamaeleon to a wide range of cadmium concentration in the marine environment. © 2013 Wiley Periodicals, Inc.

  16. A Decoupling Control Algorithm for Unwinding Tension System Based on Active Disturbance Rejection Control

    Directory of Open Access Journals (Sweden)

    Shanhui Liu

    2013-01-01

    Full Text Available This paper presents a new control methodology based on active disturbance rejection control (ADRC for designing the tension decoupling controller of the unwinding system in a gravure printing machine. The dynamic coupling can be actively estimated and compensated in real time, which makes feedback control an ideal approach to designing the decoupling controller of the unwinding system. This feature is unique to ADRC. In this study, a nonlinear mathematical model is established according to the working principle of the unwinding system. A decoupling model is also constructed to determine the order and decoupling plant of the unwinding system. Based on the order and decoupling plant, an ADRC decoupling control methodology is designed to enhance the tension stability in the unwinding system. The effectiveness and capability of the proposed methodology are verified through simulation and experiments. The results show that the proposed strategy not only realises a decoupling control for the unwinding system but also has an effective antidisturbance capability and is robust.

  17. Unwinding focal segmental glomerulosclerosis [version 1; referees: 3 approved

    Directory of Open Access Journals (Sweden)

    Vasil Peev

    2017-04-01

    Full Text Available Focal segmental glomerulosclerosis (FSGS represents the most common primary glomerular disease responsible for the development of end-stage renal disease (ESRD in the United States (US. The disease progresses from podocyte injury to chronic kidney disease (CKD, ultimately leading to total nephron degeneration. Extensive basic science research has been conducted to unwind the mechanisms of FSGS and, with those insights, understand major contributors of CKD in general. As a result, several putative molecules and pathways have been studied, all implicated in the disease; some serve, in addition, as early biomarkers. The ongoing research is currently focusing on understanding how these molecules and pathways can interplay and be utilized as potential diagnostic and therapeutic targets. Among these molecules, the soluble urokinase plasminogen activating receptor (suPAR has been studied in detail, both clinically and from a basic science perspective. By now, it has emerged as the earliest and most robust marker of future CKD. Other circulating factors harming podocytes include anti-CD40 auto-antibody and possibly cardiotrophin-like cytokine factor-1. Understanding these factors will aid our efforts to ultimately cure FSGS and possibly treat a larger portion of CKD patients much more effectively.

  18. Facile synthesis of Graphene Oxide/Double-stranded DNA ...

    Indian Academy of Sciences (India)

    assembled liquid crystals and three-dimensional hydrogels of graphene oxidewith double-stranded DNA by simple mixing in an aqueous buffer media without unwinding double-strandedDNA to single-stranded DNA. The GO/dsDNA hydrogels have ...

  19. Dynamic torsional unwinding of southern pine tracheids as observed in the scanning electron microscope

    Science.gov (United States)

    C.W. McMillin

    1974-01-01

    In previous research on the process for making groundwood in a double-disk refiner, a theoretical stress analysis indicated that tracheids of Pinus taeda L. may fail while under torsional stress and unwind into ribbonlike elements. Such elements provide the coherence necessary for strength development in these pulps. Depending upon their physical...

  20. DNA-nuclear matrix interactions and ionizing radiation sensitivity

    International Nuclear Information System (INIS)

    Schwartz, J.L.; Chicago Univ., IL; Vaughan, A.T.M.

    1993-01-01

    The association between inherent ionizing radiation sensitivity and DNA supercoil unwinding in mammalian cells suggests that the DNA-nuclear matrix attachment region (MAR) plays an important role in radiation response. In radioresistant cells, the MAR structure may exist in a more stable, open configuration, limiting DNA unwinding following strand break induction and maintaining DNA ends in close proximity for more rapid and accurate rejoining. In addition, the open configuration at these matrix attachment sites may serve to facilitate rapid DNA processing of breaks by providing (1) sites for repair proteins to collect and (2) energy to drive enzymatic reactions

  1. Engine Cylinder Temperature Control

    Science.gov (United States)

    Kilkenny, Jonathan Patrick; Duffy, Kevin Patrick

    2005-09-27

    A method and apparatus for controlling a temperature in a combustion cylinder in an internal combustion engine. The cylinder is fluidly connected to an intake manifold and an exhaust manifold. The method and apparatus includes increasing a back pressure associated with the exhaust manifold to a level sufficient to maintain a desired quantity of residual exhaust gas in the cylinder, and varying operation of an intake valve located between the intake manifold and the cylinder to an open duration sufficient to maintain a desired quantity of fresh air from the intake manifold to the cylinder, wherein controlling the quantities of residual exhaust gas and fresh air are performed to maintain the temperature in the cylinder at a desired level.

  2. Cylinder monitoring program

    Energy Technology Data Exchange (ETDEWEB)

    Alderson, J.H. [Martin Marietta Energy Systems, Inc., Paducah, KY (United States)

    1991-12-31

    Cylinders containing depleted uranium hexafluoride (UF{sub 6}) in storage at the Department of Energy (DOE) gaseous diffusion plants, managed by Martin Marietta Energy Systems, Inc., are being evaluated to determine their expected storage life. Cylinders evaluated recently have been in storage service for 30 to 40 years. In the present environment, the remaining life for these storage cylinders is estimated to be 30 years or greater. The group of cylinders involved in recent tests will continue to be monitored on a periodic basis, and other storage cylinders will be observed as on a statistical sample population. The program has been extended to all types of large capacity UF{sub 6} cylinders.

  3. Antennas on circular cylinders

    DEFF Research Database (Denmark)

    Knudsen, H. L.

    1959-01-01

    On the basis of the results obtained by Silver and Saunders [4] for the field radiated from an arbitrary slot in a perfectly conducting circular cylinder, expressions have been derived for the field radiated by a narrow helical slot, with an arbitrary aperture field distribution, in a circular...... antenna in a circular cylinder. By a procedure similar to the one used by Silver and Saunders, expressions have been derived for the field radiated from an arbitrary surface current distribution on a cylinder surface coaxial with a perfectly conducting cylinder. The cases where the space between the two...

  4. Delamination of Composite Cylinders

    Science.gov (United States)

    Davies, Peter; Carlsson, Leif A.

    The delamination resistance of filament wound glass/epoxy cylinders has been characterized for a range of winding angles and fracture mode ratios using beam fracture specimens. The results reveal that the delamination fracture resistance increases with increasing winding angle and mode II (shear) fraction (GΠ/G). It was also found that interlaced fiber bundles in the filament wound cylinder wall acted as effective crack arresters in mode I loading. To examine the sensitivity of delamina-tion damage on the strength of the cylinders, external pressure tests were performed on filament-wound glass/epoxy composite cylinders with artificial defects and impact damage. The results revealed that the cylinder strength was insensitive to the presence of single delaminations but impact damage caused reductions in failure pressure. The insensitivity of the failure pressure to a single delamination is attributed to the absence of buckling of the delaminated sublaminates before the cylinder wall collapsed. The impacted cylinders contained multiple delaminations, which caused local reduction in the compressive load capability and reduction in failure pressure. The response of glass/epoxy cylinders was compared to impacted carbon reinforced cylinders. Carbon/epoxy is more sensitive to damage but retains higher implosion resistance while carbon/PEEK shows the opposite trend.

  5. Bypass of a protein barrier by a replicative DNA helicase

    NARCIS (Netherlands)

    Yardimci, Hasan; Wang, Xindan; Loveland, Anna B.; Tappin, Inger; Rudner, David Z.; Hurwitz, Jerard; van Oijen, Antoine M.; Walter, Johannes C.

    2012-01-01

    Replicative DNA helicases generally unwind DNA as a single hexamer that encircles and translocates along one strand of the duplex while excluding the complementary strand (known as steric exclusion). By contrast, large T antigen, the replicative DNA helicase of the simian virus 40 (SV40), is

  6. Effect of temperature on DNA double helix: An insight from ...

    Indian Academy of Sciences (India)

    The three-dimensional structure of DNA contains various sequence-dependent structural information, which control many cellular processes in life, such as replication, transcription, DNA repair, etc. For the above functions, DNA double helices need to unwind or melt locally, which is different from terminal melting, as often ...

  7. Fiber Tracking Cylinder Nesting

    International Nuclear Information System (INIS)

    Stredde, H.

    1999-01-01

    The fiber tracker consists of 8 concentric carbon fiber cylinders of varying diameters, from 399mm to 1032.2mm and two different lengths. 1.66 and 2.52 meters. Each completed cylinder is covered over the entire o.d. with scintillating fiber ribbons with a connector on each ribbon. These ribbons are axial (parallel to the beam line) at one end and stereo (at 3 deg. to the beam line) at the other. The ribbon connectors have dowel pins which are used to match with the connectors on the wave guide ribbons. These dowel pins are also used during the nesting operation, locating and positioning measurements. The nesting operation is the insertion of one cylinder into another, aligning them with one another and fastening them together into a homogeneous assembly. For ease of assembly. the nesting operation is accomplished working from largest diameter to smallest. Although the completed assembly of all 8 cylinders glued and bolted together is very stiff. individual cylinders are relatively flexible. Therefore. during this operation, No.8 must be supported in a manner which maintains its integrity and yet allows the insertion of No.7. This is accomplished by essentially building a set of dummy end plates which replicate a No.9 cylinder. These end plates are mounted on a wheeled cart that becomes the nesting cart. Provisions for a protective cover fastened to these rings has been made and will be incorporated in finished product. These covers can be easily removed for access to No.8 and/or the connection of No.8 to No.9. Another wheeled cart, transfer cart, is used to push a completed cylinder into the cylinder(s) already mounted in the nesting cart.

  8. Tandem Cylinder Noise Predictions

    Science.gov (United States)

    Lockard, David P.; Khorrami, Mehdi R.; CHoudhari, Meelan M.; Hutcheson, Florence V.; Brooks, Thomas F.; Stead, Daniel J.

    2007-01-01

    In an effort to better understand landing-gear noise sources, we have been examining a simplified configuration that still maintains some of the salient features of landing-gear flow fields. In particular, tandem cylinders have been studied because they model a variety of component level interactions. The present effort is directed at the case of two identical cylinders spatially separated in the streamwise direction by 3.7 diameters. Experimental measurements from the Basic Aerodynamic Research Tunnel (BART) and Quiet Flow Facility (QFF) at NASA Langley Research Center (LaRC) have provided steady surface pressures, detailed off-surface measurements of the flow field using Particle Image Velocimetry (PIV), hot-wire measurements in the wake of the rear cylinder, unsteady surface pressure data, and the radiated noise. The experiments were conducted at a Reynolds number of 166 105 based on the cylinder diameter. A trip was used on the upstream cylinder to insure a fully turbulent shedding process and simulate the effects of a high Reynolds number flow. The parallel computational effort uses the three-dimensional Navier-Stokes solver CFL3D with a hybrid, zonal turbulence model that turns off the turbulence production term everywhere except in a narrow ring surrounding solid surfaces. The current calculations further explore the influence of the grid resolution and spanwise extent on the flow and associated radiated noise. Extensive comparisons with the experimental data are used to assess the ability of the computations to simulate the details of the flow. The results show that the pressure fluctuations on the upstream cylinder, caused by vortex shedding, are smaller than those generated on the downstream cylinder by wake interaction. Consequently, the downstream cylinder dominates the noise radiation, producing an overall directivity pattern that is similar to that of an isolated cylinder. Only calculations based on the full length of the model span were able to

  9. Gas Cylinder Safety, Course 9518

    Energy Technology Data Exchange (ETDEWEB)

    Glass, George [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-10-27

    This course, Gas Cylinder Safety (#9518), presents an overview of the hazards and controls associated with handling, storing, using, and transporting gas cylinders. Standard components and markings of gas cylinders are also presented, as well as the process for the procurement, delivery, and return of gas cylinders at Los Alamos National Laboratory (LANL).

  10. Inhibition of RecBCD enzyme by antineoplastic DNA alkylating agents.

    Science.gov (United States)

    Dziegielewska, Barbara; Beerman, Terry A; Bianco, Piero R

    2006-09-01

    To understand how bulky adducts might perturb DNA helicase function, three distinct DNA-binding agents were used to determine the effects of DNA alkylation on a DNA helicase. Adozelesin, ecteinascidin 743 (Et743) and hedamycin each possess unique structures and sequence selectivity. They bind to double-stranded DNA and alkylate one strand of the duplex in cis, adding adducts that alter the structure of DNA significantly. The results show that Et743 was the most potent inhibitor of DNA unwinding, followed by adozelesin and hedamycin. Et743 significantly inhibited unwinding, enhanced degradation of DNA, and completely eliminated the ability of the translocating RecBCD enzyme to recognize and respond to the recombination hotspot chi. Unwinding of adozelesin-modified DNA was accompanied by the appearance of unwinding intermediates, consistent with enzyme entrapment or stalling. Further, adozelesin also induced "apparent" chi fragment formation. The combination of enzyme sequestering and pseudo-chi modification of RecBCD, results in biphasic time-courses of DNA unwinding. Hedamycin also reduced RecBCD activity, albeit at increased concentrations of drug relative to either adozelesin or Et743. Remarkably, the hedamycin modification resulted in constitutive activation of the bottom-strand nuclease activity of the enzyme, while leaving the ability of the translocating enzyme to recognize and respond to chi largely intact. Finally, the results show that DNA alkylation does not significantly perturb the allosteric interaction that activates the enzyme for ATP hydrolysis, as the efficiency of ATP utilization for DNA unwinding is affected only marginally. These results taken together present a unique response of RecBCD enzyme to bulky DNA adducts. We correlate these effects with the recently determined crystal structure of the RecBCD holoenzyme bound to DNA.

  11. Topoisomerase II-mediated DNA cleavage by adocia- and xestoquinones from the Philippine sponge Xestospongia sp.

    Science.gov (United States)

    Concepción, G P; Foderaro, T A; Eldredge, G S; Lobkovsky, E; Clardy, J; Barrows, L R; Ireland, C M

    1995-10-27

    Investigation of an orange Xestospongia sp. sponge collected at Cape Bolinao in northern Luzon, Philippines, yielded the known compounds adociaquinones A and B (1, 2) and six new metabolites, secoadociaquinones A and B (3, 4), 14-methoxyxestoquinone (5), 15-methoxyxestoquinone (6), 15-chloro-14-hydroxyxestoquinone (7), and 14-chloro-15-hydroxyxestoquinone (8). All compounds showed inhibition of topoisomerase II in catalytic DNA unwinding and/or decatenation assays. Furthermore, adociaquinone B showed activity in a KSDS assay, suggesting it inhibits the enzyme by freezing the enzyme-DNA cleavable complex. Interestingly, adociaquinone B did not displace ethidium bromide from DNA or unwind supercoiled DNA, implying it does not intercalate DNA.

  12. Recombinant human immunodeficiency virus type 1 nucleocapsid (NCp7) protein unwinds tRNA.

    Science.gov (United States)

    Khan, R; Giedroc, D P

    1992-04-05

    The nucleocapsid protein (NC) of all animal retroviruses, encoded by the gag gene, is the major structural protein of the core ribonucleoprotein complex, bound to genomic RNA in mature virions. NC is also thought to play one or more accessory roles in reverse transcription. Mature NC (p7NC) from human immunodeficiency virus type 1 (HIV-1) is a 71-amino acid, basic protein which contains two Cys3His Zn(II) retroviral-type zinc finger domains. Herein, we describe the subcloning and expression of HIV-1 NC, denoted NC71, from an inducible phage T7 RNA polymerase promoter in Escherichia coli. Purified NC71 can be reversibly reconstituted with 2 g.at Zn(II) determined by atomic absorption. Ultraviolet circulation dichroism spectroscopy has been used to characterize the complexes between highly purified NC71 and the RNA homopolynucleotide poly(A) and E. coli tRNA(mixed). On poly(A), Zn2 NC71 is characterized by an apparent site size n = 15 +/- 3 nucleotides and high affinity (Kapp = 3 x 10(7) M-1) and moderately cooperative (omega approximately 170 +/- 25) binding. A mixture of E. coli tRNA species (tRNA(mixed) was used to probe the conformational changes induced in tRNA upon binding of HIV-1 NC71. Two structural forms of tRNA(mixed), which differ in their degree of tertiary structure, were assayed for their susceptibility to denaturation by NC71. Five molar monomer equivalents of NC71 are required to denature the "inactive" tRNA in the absence of Mg2+. A Zn(II)-free, oxidized form of NC71 was also shown to unwind inactive tRNA with the same efficiency and stoichiometry. The detailed spectral changes which occur on NC-induced denaturation closely mimic temperature-induced denaturation of inactive tRNA(mixed). The prototype helix-destabilizing protein, T4 gene 32 protein, is unable to unwind this form of tRNA under the same conditions. The stoichiometry of unwinding of inactive tRNA by NC71 is consistent with the site size determined with poly(A). An "active" form of t

  13. BLM helicase measures DNA unwound before switching strands and hRPA promotes unwinding reinitiation

    Czech Academy of Sciences Publication Activity Database

    Yodh, J.G.; Stevens, B.C.; Kanagaraj, R.; Janščák, Pavel; Ha, T.

    2009-01-01

    Roč. 28, č. 4 (2009), s. 405-416 ISSN 0261-4189 Institutional research plan: CEZ:AV0Z50520514 Keywords : Bloom syndrome * FRET * helicase * hRPA * single molecule Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 8.993, year: 2009

  14. Structural basis for DNA strand separation by a hexameric replicative helicase

    Science.gov (United States)

    Chaban, Yuriy; Stead, Jonathan A.; Ryzhenkova, Ksenia; Whelan, Fiona; Lamber, Ekaterina P.; Antson, Alfred; Sanders, Cyril M.; Orlova, Elena V.

    2015-01-01

    Hexameric helicases are processive DNA unwinding machines but how they engage with a replication fork during unwinding is unknown. Using electron microscopy and single particle analysis we determined structures of the intact hexameric helicase E1 from papillomavirus and two complexes of E1 bound to a DNA replication fork end-labelled with protein tags. By labelling a DNA replication fork with streptavidin (dsDNA end) and Fab (5′ ssDNA) we located the positions of these labels on the helicase surface, showing that at least 10 bp of dsDNA enter the E1 helicase via a side tunnel. In the currently accepted ‘steric exclusion’ model for dsDNA unwinding, the active 3′ ssDNA strand is pulled through a central tunnel of the helicase motor domain as the dsDNA strands are wedged apart outside the protein assembly. Our structural observations together with nuclease footprinting assays indicate otherwise: strand separation is taking place inside E1 in a chamber above the helicase domain and the 5′ passive ssDNA strands exits the assembly through a separate tunnel opposite to the dsDNA entry point. Our data therefore suggest an alternative to the current general model for DNA unwinding by hexameric helicases. PMID:26240379

  15. Phase unwinding for dictionary compression with multiple channel transmission in magnetic resonance fingerprinting.

    Science.gov (United States)

    Lattanzi, Riccardo; Zhang, Bei; Knoll, Florian; Assländer, Jakob; Cloos, Martijn A

    2017-12-24

    Magnetic Resonance Fingerprinting reconstructions can become computationally intractable with multiple transmit channels, if the B 1 + phases are included in the dictionary. We describe a general method that allows to omit the transmit phases. We show that this enables straightforward implementation of dictionary compression to further reduce the problem dimensionality. We merged the raw data of each RF source into a single k-space dataset, extracted the transceiver phases from the corresponding reconstructed images and used them to unwind the phase in each time frame. All phase-unwound time frames were combined in a single set before performing SVD-based compression. We conducted synthetic, phantom and in-vivo experiments to demonstrate the feasibility of SVD-based compression in the case of two-channel transmission. Unwinding the phases before SVD-based compression yielded artifact-free parameter maps. For fully sampled acquisitions, parameters were accurate with as few as 6 compressed time frames. SVD-based compression performed well in-vivo with highly under-sampled acquisitions using 16 compressed time frames, which reduced reconstruction time from 750 to 25min. Our method reduces the dimensions of the dictionary atoms and enables to implement any fingerprint compression strategy in the case of multiple transmit channels. Copyright © 2018 Elsevier Inc. All rights reserved.

  16. QCM-based rupture force measurement as a tool to study DNA dehybridization and duplex stability.

    Science.gov (United States)

    Dultsev, Fedor N; Kolosovsky, Eugeny A; Lomzov, Alexander A; Pyshnyi, Dmitrii V

    2017-02-01

    The stability of double-stranded DNA (dsDNA) was assessed on the basis of unwinding force measurement. Unwinding force was measured directly with a quartz crystal microbalance (QCM). The amplitude of its surface oscillations was controlled by supplying variable alternate voltage. Under smoothly increasing amplitude of QCM surface oscillations, dsDNA fixed on QCM surface through one of its ends got unwound. This procedure allows reliable measurement of rupture force as small as 5-10 pN. It was demonstrated that oscillations of the surface, with dsDNA bound through one of its ends to this surface, at a frequency of 14 MHz, cause helix unwinding to form two complementary parts due to viscous forces of the liquid medium. Unwinding starts at the upper end. This was proven using oligonucleotide duplexes containing mismatches in different positions. For duplexes containing complementary 20 base pairs, the helix unwinding force is equal to 30-40 pN, which is in agreement with the data obtained by means of atomic-force microscopy (AFM) for the case of unzipping mode. Graphical Abstract Rupture force depending on mismatch position in dsDNA.

  17. DNA conformation of Chinese hamster V79 cells and sensitivity to ionizing radiation

    International Nuclear Information System (INIS)

    Olive, P.L.; Hilton, J.; Durand, R.E.

    1986-01-01

    Chinese hamster V79 cells grown for 20 h in suspension culture form small clusters of cells (spheroids) which are more resistant to killing by ionizing radiation than V79 cells grown as monolayers. This resistance appears to be due to the greater capacity of cells grown in contact to repair radiation damage. Attempts to relate this ''contact effect'' to differences in DNA susceptibility or DNA repair capacity have provided conflicting results. Two techniques, alkaline sucrose gradient sedimentation and alkaline elution, show no difference in the amounts of radiation-induced DNA single-strand breakage or its repair between suspension or monolayer cells. However, using the alkali-unwinding assay, the rate of DNA unwinding is much slower for suspension cells than for monolayer cells. Interestingly, a decrease in salt concentration or in pH of the unwinding solution eliminates these differences in DNA unwinding kinetics. A fourth assay, sedimentation of nucleoids on neutral sucrose gradients, also shows a significant decrease in radiation damage produced in suspension compared to monolayer cultures. It is believed that this assay measures differences in DNA conformation (supercoiling) as well as differences in DNA strand breakage. We conclude from these four assays that the same number of DNA strand breaks/Gy is produced in monolayer and spheroid cells. However, changes in DNA conformation or packaging occur when cells are grown as spheroids, and these changes are responsible for reducing DNA damage by ionizing radiation

  18. Anti-Unwinding Attitude Control with Fixed-Time Convergence for a Flexible Spacecraft

    Directory of Open Access Journals (Sweden)

    Chutiphon Pukdeboon

    2017-01-01

    Full Text Available This paper investigates the fixed-time attitude tracking control problem for flexible spacecraft with unknown bounded disturbances. First, with the knowledge of norm upper bounds of external disturbances and the coupling effect of flexible modes, a novel robust fixed-time controller is designed to deal with this problem. Second, the controller is further enhanced by an adaptive law to avoid the knowledge of norm upper bounds of external disturbances and coupling effect of flexible modes. This control law guarantees the convergence of attitude tracking errors in fixed time where the settling time is bounded by a constant independent of initial conditions. Moreover, the proposed controllers can prevent the unwinding phenomenon. Simulation results are presented to demonstrate the performance of the proposed control scheme.

  19. Anaesthesia gas supply: gas cylinders.

    Science.gov (United States)

    Srivastava, Uma

    2013-09-01

    Invention of oxygen cylinder was one of the most important developments in the field of medical practice. Oxygen and other gases were compressed and stored at high pressure in seamless containers constructed from hand-forged steel in1880. Materials technology has continued to evolve and now medical gas cylinders are generally made of steel alloys or aluminum. The filling pressure as well as capacity has increased considerably while at the same time the weight of cylinders has reduced. Today oxygen cylinder of equivalent size holds a third more oxygen but weighs about 20 kg less. The cylinders are of varying sizes and are color coded. They are tested at regular intervals by the manufacturer using hydraulic, impact, and tensile tests. The top end of the cylinder is fitted with a valve with a variety of number and markings stamped on it. Common valve types include: Pin index valve, bull nose, hand wheel and integral valve. The type of valve varies with cylinder size. Small cylinders have a pin index valve while large have a bull nose type. Safety features in the cylinder are: Color coding, pin index, pressure relief device, Bodok seal, and label attached etc., Safety rules and guidelines must be followed during storage, installation and use of cylinders to ensure safety of patients, hospital personnel and the environment.

  20. Anaesthesia gas supply: Gas cylinders

    Directory of Open Access Journals (Sweden)

    Uma Srivastava

    2013-01-01

    Full Text Available Invention of oxygen cylinder was one of the most important developments in the field of medical practice. Oxygen and other gases were compressed and stored at high pressure in seamless containers constructed from hand-forged steel in1880. Materials technology has continued to evolve and now medical gas cylinders are generally made of steel alloys or aluminum. The filling pressure as well as capacity has increased considerably while at the same time the weight of cylinders has reduced. Today oxygen cylinder of equivalent size holds a third more oxygen but weighs about 20 kg less. The cylinders are of varying sizes and are color coded. They are tested at regular intervals by the manufacturer using hydraulic, impact, and tensile tests. The top end of the cylinder is fitted with a valve with a variety of number and markings stamped on it. Common valve types include: Pin index valve, bull nose, hand wheel and integral valve. The type of valve varies with cylinder size. Small cylinders have a pin index valve while large have a bull nose type. Safety features in the cylinder are: Color coding, pin index, pressure relief device, Bodok seal, and label attached etc., Safety rules and guidelines must be followed during storage, installation and use of cylinders to ensure safety of patients, hospital personnel and the environment.

  1. Anaesthesia Gas Supply: Gas Cylinders

    OpenAIRE

    Srivastava, Uma

    2013-01-01

    Invention of oxygen cylinder was one of the most important developments in the field of medical practice. Oxygen and other gases were compressed and stored at high pressure in seamless containers constructed from hand-forged steel in1880. Materials technology has continued to evolve and now medical gas cylinders are generally made of steel alloys or aluminum. The filling pressure as well as capacity has increased considerably while at the same time the weight of cylinders has reduced. Today o...

  2. Focal surfaces of hyperbolic cylinders

    Science.gov (United States)

    Georgiev, Georgi Hristov; Pavlov, Milen Dimov

    2017-12-01

    Cylindrical surfaces have many applications in geometric modeling, architecture and other branches of engineering. In this paper, we describe two cylindrical surfaces associated to a given hyperbolic cylinder. The first one is a focal surface which is determined by reciprocal principle curvature of the hyperbolic cylinder. The second one is a generalized focal surface obtained by reciprocal mean curvature of the same hyperbolic cylinder. In particular, we show that each of these surfaces admits three different parametric representations. As consequence, it is proved that the focal and generalized focal surfaces of the hyperbolic cylinder are rational surfaces. An illustrative example is included.

  3. Carcinogenic heavy metals replace Ca2+ for DNA binding and annealing activities of mono-ubiquitinated annexin A1 homodimer.

    Science.gov (United States)

    Hirata, Aiko; Corcoran, George B; Hirata, Fusao

    2010-10-01

    Mono-ubiquitinated annexin A1 was purified from rat liver nuclei. The homodimer form of mono-ubiquitinated annexin A1 was able to unwind dsDNA in a Mg(2+)- and ATP-dependent manner, and to anneal ssDNA in a Ca(2+)-dependent manner. Phospholipids decreased the concentration of Ca(2+) required for maximal annealing activity. Heavy metals such as As(3+), Cr(6+), Pb(2+) and Cd(2+) substituted for Ca(2+) in the ssDNA binding and annealing activities of annexin A1. While these metals inhibited the unwinding of dsDNA by nuclear annexin A1 in the presence of Mg(2+) and ATP, they enhanced dsDNA-dependent ATPase activity of annexin A1. Heavy metals may have produced dsDNA, a substrate for the DNA unwinding reaction, via the DNA annealing reaction. DNA synthesomes were isolated from L5178Y tk(+/-) mouse lymphoma cells in exponential growth, and were found to contain helicase activities. The As(3+)- or Cr(6+)-induced increases in ssDNA binding activity of DNA synthesomes were reduced by a mono-specific anti-annexin A1 antibody, but not by anti-Ig antibody. Anti-annexin A1 antibody also blocked the inhibitory and stimulatory effects of As(3+) or Cr(6+) towards DNA unwinding and annealing activities of DNA synthesomes. Based on these observations, it can be concluded that the effects of heavy metals on DNA annealing and unwinding activities are mediated, at least in substantial part, through actions of the mono-ubiquitinated annexin A1 homodimer. Copyright (c) 2010 Elsevier Inc. All rights reserved.

  4. Brachistochrone for a rolling cylinder

    Science.gov (United States)

    Legeza, V. P.

    2010-02-01

    The motion of a heavy homogeneous cylinder is considered as a no-slip rolling along the desired curve. We obtain a functional in the form of the total time of the cylinder rolling and solve the corresponding variational problem of minimizing this functional. We obtain an algebraic equation for the directional line of steepest descent, brachistochrone, in parametric form. We use the equation of motion of the cylinder with constraint reaction to determine the conditions of implementation of its pure rolling without separation and slip with respect to the brachistochrone.

  5. Enzymatic activities and DNA substrate specificity of Mycobacterium tuberculosis DNA helicase XPB.

    Science.gov (United States)

    Balasingham, Seetha V; Zegeye, Ephrem Debebe; Homberset, Håvard; Rossi, Marie L; Laerdahl, Jon K; Bohr, Vilhelm A; Tønjum, Tone

    2012-01-01

    XPB, also known as ERCC3 and RAD25, is a 3' → 5' DNA repair helicase belonging to the superfamily 2 of helicases. XPB is an essential core subunit of the eukaryotic basal transcription factor complex TFIIH. It has two well-established functions: in the context of damaged DNA, XPB facilitates nucleotide excision repair by unwinding double stranded DNA (dsDNA) surrounding a DNA lesion; while in the context of actively transcribing genes, XPB facilitates initiation of RNA polymerase II transcription at gene promoters. Human and other eukaryotic XPB homologs are relatively well characterized compared to conserved homologs found in mycobacteria and archaea. However, more insight into the function of bacterial helicases is central to understanding the mechanism of DNA metabolism and pathogenesis in general. Here, we characterized Mycobacterium tuberculosis XPB (Mtb XPB), a 3'→5' DNA helicase with DNA-dependent ATPase activity. Mtb XPB efficiently catalyzed DNA unwinding in the presence of significant excess of enzyme. The unwinding activity was fueled by ATP or dATP in the presence of Mg(2+)/Mn(2+). Consistent with the 3'→5' polarity of this bacterial XPB helicase, the enzyme required a DNA substrate with a 3' overhang of 15 nucleotides or more. Although Mtb XPB efficiently unwound DNA model substrates with a 3' DNA tail, it was not active on substrates containing a 3' RNA tail. We also found that Mtb XPB efficiently catalyzed ATP-independent annealing of complementary DNA strands. These observations significantly enhance our understanding of the biological roles of Mtb XPB.

  6. Enzymatic activities and DNA substrate specificity of Mycobacterium tuberculosis DNA helicase XPB.

    Directory of Open Access Journals (Sweden)

    Seetha V Balasingham

    Full Text Available XPB, also known as ERCC3 and RAD25, is a 3' → 5' DNA repair helicase belonging to the superfamily 2 of helicases. XPB is an essential core subunit of the eukaryotic basal transcription factor complex TFIIH. It has two well-established functions: in the context of damaged DNA, XPB facilitates nucleotide excision repair by unwinding double stranded DNA (dsDNA surrounding a DNA lesion; while in the context of actively transcribing genes, XPB facilitates initiation of RNA polymerase II transcription at gene promoters. Human and other eukaryotic XPB homologs are relatively well characterized compared to conserved homologs found in mycobacteria and archaea. However, more insight into the function of bacterial helicases is central to understanding the mechanism of DNA metabolism and pathogenesis in general. Here, we characterized Mycobacterium tuberculosis XPB (Mtb XPB, a 3'→5' DNA helicase with DNA-dependent ATPase activity. Mtb XPB efficiently catalyzed DNA unwinding in the presence of significant excess of enzyme. The unwinding activity was fueled by ATP or dATP in the presence of Mg(2+/Mn(2+. Consistent with the 3'→5' polarity of this bacterial XPB helicase, the enzyme required a DNA substrate with a 3' overhang of 15 nucleotides or more. Although Mtb XPB efficiently unwound DNA model substrates with a 3' DNA tail, it was not active on substrates containing a 3' RNA tail. We also found that Mtb XPB efficiently catalyzed ATP-independent annealing of complementary DNA strands. These observations significantly enhance our understanding of the biological roles of Mtb XPB.

  7. Rolling Cylinder Phase 1bis

    DEFF Research Database (Denmark)

    Margheritini, Lucia

    Cylinder Phase 1: proof of concept and first optimization”, DCE report 115, ISSN 1901-726X, and it is recommended that the two are consulted together as they were firstly agreed to be in one document. The present report aims at estimate the efficiency of the Rolling Cylinder long model (previously...... optimized), by mean of physical tests in irregular waves. Several difficulties have been encountered during the testing, the biggest of witch being the extremely unfriendly torque measuring system....

  8. Video analysis of rolling cylinders

    Science.gov (United States)

    Phommarach, S.; Wattanakasiwich, P.; Johnston, I.

    2012-03-01

    In this work, we studied the rolling motion of solid and hollow cylinders down an inclined plane at different angles. The motions were captured on video at 300 frames s - 1, and the videos were analyzed frame by frame using video analysis software. Data from the real motion were compared with the theory of rolling down an inclined plane without slipping. From the experiment, the acceleration does not depend on the cylinder mass as indicated from the theory. For the wood-steel surface, we found that the coefficient of static friction was equal to 0.131 and the critical angle for the solid cylinder was 21.45°. The critical angle for the hollow cylinder depends on the inner and outer radius of the cylinder. Motion paths of a point on the hollow cylinder at small and large angles were shown to elucidate the pure rolling condition. Finally, we demonstrated that total mechanical energy was conserved during the pure rolling motion. This confirms that work done by the friction force is zero. We will use these results to design an interactive lecture demonstration on rolling without slipping.

  9. Pressure cylinders under fire condition

    Directory of Open Access Journals (Sweden)

    Jan Hora

    2016-03-01

    Full Text Available The presence of pressure cylinders under fire conditions significantly increases the risk rate for the intervening persons. It is considerably problematic to predict the pressure cylinders behaviour during heat exposition, its destruction progress and possible following explosion of the produced air–gas mixture because pressure cylinders and its environment generate a highly complicated dynamic system during an uncontrolled destruction. The large scale tests carried out by the Pilsen Fire and Rescue Department and the Rapid Response Unit of the Czech Republic Police in October 2012 and in May 2014 in the Military area Brdy and in the area of the former Lachema factory in Kaznějov had several objectives, namely, to record, qualify and quantify some of the aspects of an uncontrolled heat destruction procedure of an exposed pressure cylinder in an enclosed space and to qualify and describe the process of a controlled destruction of a pressure cylinder by shooting through it including basic tactical concepts. The article describes the experiments that were carried out.

  10. Single molecule measurements of DNA helicase activity with magnetic tweezers and t-test based step-finding analysis

    Science.gov (United States)

    Seol, Yeonee; Strub, Marie-Paule; Neuman, Keir C.

    2016-01-01

    Magnetic tweezers is a versatile and easy to implement single-molecule technique that has become increasingly prevalent in the study of nucleic acid based molecular motors. Here, we provide a description of the magnetic tweezers instrument and guidelines for measuring and analyzing DNA helicase activity. Along with experimental methods, we describe a robust method of single-molecule trajectory analysis based on the Student’s t-test that accommodates continuous transitions in addition to the discrete transitions assumed in most widely employed analysis routines. To illustrate the single-molecule unwinding assay and the analysis routine, we provide DNA unwinding measurements of Escherichia coli RecQ helicase under a variety of conditions (Na+, ATP, temperature, and DNA substrate geometry). These examples reveal that DNA unwinding measurements under various conditions can aid in elucidating the unwinding mechanism of DNA helicase but also emphasize that environmental effects on DNA helicase activity must be considered in relation to in vivo activity and mechanism. PMID:27131595

  11. A mechanical mechanism for translocation of ring-shaped helicases on DNA and its demonstration in a macroscopic simulation system

    Science.gov (United States)

    Chou, Y. C.

    2018-04-01

    The asymmetry in the two-layered ring structure of helicases and the random thermal fluctuations of the helicase and DNA molecules are considered as the bases for the generation of the force required for translocation of the ring-shaped helicase on DNA. The helicase comprises a channel at its center with two unequal ends, through which strands of DNA can pass. The random collisions between the portion of the DNA strand in the central channel and the wall of the channel generate an impulsive force toward the small end. This impulsive force is the starting point for the helicase to translocate along the DNA with the small end in front. Such a physical mechanism may serve as a complementary for the chemomechanical mechanism of the translocation of helicase on DNA. When the helicase arrives at the junction of ssDNA and dsDNA (a fork), the collision between the helicase and the closest base pair may produce a sufficient impulsive force to break the weak hydrogen bond of the base pair. Thus, the helicase may advance and repeat the process of unwinding the dsDNA strand. This mechanism was tested in a macroscopic simulation system where the helicase was simulated using a truncated-cone structure and DNA was simulated with bead chains. Many features of translocation and unwinding such as translocation on ssDNA and dsDNA, unwinding of dsDNA, rewinding, strand switching, and Holliday junction resolution were reproduced.

  12. Filament winding cylinders. I - Process model

    Science.gov (United States)

    Lee, Soo-Yong; Springer, George S.

    1990-01-01

    A model was developed which describes the filament winding process of composite cylinders. The model relates the significant process variables such as winding speed, fiber tension, and applied temperature to the thermal, chemical and mechanical behavior of the composite cylinder and the mandrel. Based on the model, a user friendly code was written which can be used to calculate (1) the temperature in the cylinder and the mandrel, (2) the degree of cure and viscosity in the cylinder, (3) the fiber tensions and fiber positions, (4) the stresses and strains in the cylinder and in the mandrel, and (5) the void diameters in the cylinder.

  13. Enhancement of polarizabilities of cylinders with cylinder-slab resonances.

    Science.gov (United States)

    Xiao, Meng; Huang, Xueqin; Liu, H; Chan, C T

    2015-02-02

    If an object is very small in size compared with the wavelength of light, it does not scatter light efficiently. It is hence difficult to detect a very small object with light. We show using analytic theory as well as full wave numerical calculation that the effective polarizability of a small cylinder can be greatly enhanced by coupling it with a superlens type metamaterial slab. This kind of enhancement is not due to the individual resonance effect of the metamaterial slab, nor due to that of the object, but is caused by a collective resonant mode between the cylinder and the slab. We show that this type of particle-slab resonance which makes a small two-dimensional object much "brighter" is actually closely related to the reverse effect known in the literature as "cloaking by anomalous resonance" which can make a small cylinder undetectable. We also show that the enhancement of polarizability can lead to strongly enhanced electromagnetic forces that can be attractive or repulsive, depending on the material properties of the cylinder.

  14. Protein Displacement by Herpes Helicase-Primase and the Key Role of UL42 during Helicase-Coupled DNA Synthesis by the Herpes Polymerase.

    Science.gov (United States)

    Dickerson, Sarah Michelle; Kuchta, Robert D

    2017-05-30

    The herpes helicase-primase (UL5-UL8-UL52) very inefficiently unwinds double-stranded DNA. To better understand the mechanistic consequences of this inefficiency, we investigated protein displacement activity by UL5-UL8-UL52, as well as the impact of coupling DNA synthesis by the herpes polymerase with helicase activity. While the helicase can displace proteins bound to the lagging strand template, bound proteins significantly impede helicase activity. Remarkably, UL5-UL8-UL52, an extremely inefficient helicase, disrupts the exceptionally tight interaction between streptavidin and biotin on the lagging strand template. It also unwinds DNA containing streptavidin bound to the leading strand template, although it does not displace the streptavidin. These data suggest that the helicase may largely or completely wrap around the lagging strand template, with minimal interactions with the leading strand template. We utilized synthetic DNA minicircles to study helicase activity coupled with the herpes polymerase-processivity factor (UL30-UL42). Coupling greatly enhances unwinding of DNA, although bound proteins still inhibit helicase activity. Surprisingly, while UL30-UL42 and two noncognate polymerases (Klenow Fragment and T4 DNA polymerase) all stimulate unwinding of DNA by the helicase, the isolated UL30 polymerase (i.e., no UL42 processivity factor) binds to the replication fork but in a manner that is incompetent in terms of coupled helicase-polymerase activity.

  15. Cycloidal pendulum with a rolling cylinder

    Science.gov (United States)

    Legeza, V. P.

    2012-07-01

    Free vibrations of a heavy homogeneous cylinder rolling in a cylindrical cavity whose directing curve is a brachistochrone are considered. The equation of motion of the cylinder is derived and the circular frequency of free vibrations of the cylinder center of mass is determined. An analogy between the cycloidal pendulum with a rolling cylinder and the classical cycloidal pendulum in the form of a material point is obtained.

  16. Cylinder components properties, applications, materials

    CERN Document Server

    2016-01-01

    Owing to the ever-increasing requirements to be met by gasoline and diesel engines in terms of CO2 reduction, emission behavior, weight, and service life, a comprehensive understanding of combustion engine components is essential today. It is no longer possible for professionals in automotive engineering to manage without the corresponding expertise, whether they work in the field of design, development, testing, or maintenance. This technical book provides in-depth answers to questions about design, production, and machining of cylinder components. In this second edition, every section has been revised and expanded to include the latest developments in the combustion engine. Content Piston rings Piston pins and piston pin circlips Bearings Connecting rods Crankcase and cylinder liners Target audience Engineers in the field of engine development and maintenanceLecturers and students in the areas of mechanical engineering, engine technology, and vehicle constructionAnyone interested in technology Publisher MAH...

  17. Vortex shedding from tandem cylinders

    Science.gov (United States)

    Alam, Md. Mahbub; Elhimer, Mehdi; Wang, Longjun; Jacono, David Lo; Wong, C. W.

    2018-03-01

    An experimental investigation is conducted on the flow around tandem cylinders for ranges of diameter ratio d/ D = 0.25-1.0, spacing ratio L/ d = 5.5-20, and Reynolds number Re = 0.8 × 104-2.42 × 104, where d and D are the diameters of the upstream and downstream cylinders, respectively, L is the distance from the upstream cylinder center to the forward stagnation point of the downstream one. The focus is given on examining the effects of d/ D, L/ d and Re on Strouhal number St, flow structures and fluid forces measured using hotwire, particle image velocimetry (PIV) and load cell measurement techniques, respectively. Changes in d/ D and L/ d in the ranges examined lead to five flow regimes, namely lock-in, intermittent lock-in, no lock-in, subharmonic lock-in and shear-layer reattachment regimes. Time-mean drag coefficient ( C D) and fluctuating drag and lift coefficients ({C^'D} and {C^'L}) are more sensitive to L/ d than d/ D. The scenario is opposite for St where d/ D is more prominent than L/ d to change the St. The detailed facet of the dependence on d/ D and L/ d of C D, {C^'D}, {C^'L} and St is discussed based on shear-layer velocity, approaching velocity, vortex formation length, and wake width.

  18. Photo-induced morphological winding and unwinding motion of nanoscrolls composed of niobate nanosheets with a polyfluoroalkyl azobenzene derivative

    Science.gov (United States)

    Nabetani, Yu; Takamura, Hazuki; Uchikoshi, Akino; Hassan, Syed Zahid; Shimada, Tetsuya; Takagi, Shinsuke; Tachibana, Hiroshi; Masui, Dai; Tong, Zhiwei; Inoue, Haruo

    2016-06-01

    Photo-responsive nanoscrolls can be successfully fabricated by mixing a polyfluoroalkyl azobenzene derivative and a niobate nanosheet, which is exfoliated from potassium hexaniobate. In this study, we have found that the photo-responsive nanoscroll shows a morphological motion of winding and unwinding, which is basically due to the nanosheet sliding within the nanoscroll, by efficient photo-isomerization reactions of the intercalated azobenzene in addition to the interlayer distance change of the nanoscrolls. The relative nanosheet sliding of the nanoscroll is estimated to be ca. 280 nm from the AFM morphology analysis. The distance of the sliding motion is over 20 times that of the averaged nanosheet sliding in the azobenzene/niobate hybrid film reported previously. Photo-responsive nanoscrolls can be expected to be novel photo-activated actuators and artificial muscle model materials.Photo-responsive nanoscrolls can be successfully fabricated by mixing a polyfluoroalkyl azobenzene derivative and a niobate nanosheet, which is exfoliated from potassium hexaniobate. In this study, we have found that the photo-responsive nanoscroll shows a morphological motion of winding and unwinding, which is basically due to the nanosheet sliding within the nanoscroll, by efficient photo-isomerization reactions of the intercalated azobenzene in addition to the interlayer distance change of the nanoscrolls. The relative nanosheet sliding of the nanoscroll is estimated to be ca. 280 nm from the AFM morphology analysis. The distance of the sliding motion is over 20 times that of the averaged nanosheet sliding in the azobenzene/niobate hybrid film reported previously. Photo-responsive nanoscrolls can be expected to be novel photo-activated actuators and artificial muscle model materials. Electronic supplementary information (ESI) available: Fig. S1. Photo-isomerization reaction of nanoscrolls. See DOI: 10.1039/c6nr02177h

  19. Near-atomic structural model for bacterial DNA replication initiation complex and its functional insights.

    Science.gov (United States)

    Shimizu, Masahiro; Noguchi, Yasunori; Sakiyama, Yukari; Kawakami, Hironori; Katayama, Tsutomu; Takada, Shoji

    2016-12-13

    Upon DNA replication initiation in Escherichia coli, the initiator protein DnaA forms higher-order complexes with the chromosomal origin oriC and a DNA-bending protein IHF. Although tertiary structures of DnaA and IHF have previously been elucidated, dynamic structures of oriC-DnaA-IHF complexes remain unknown. Here, combining computer simulations with biochemical assays, we obtained models at almost-atomic resolution for the central part of the oriC-DnaA-IHF complex. This complex can be divided into three subcomplexes; the left and right subcomplexes include pentameric DnaA bound in a head-to-tail manner and the middle subcomplex contains only a single DnaA. In the left and right subcomplexes, DnaA ATPases associated with various cellular activities (AAA+) domain III formed helices with specific structural differences in interdomain orientations, provoking a bend in the bound DNA. In the left subcomplex a continuous DnaA chain exists, including insertion of IHF into the DNA looping, consistent with the DNA unwinding function of the complex. The intervening spaces in those subcomplexes are crucial for DNA unwinding and loading of DnaB helicases. Taken together, this model provides a reasonable near-atomic level structural solution of the initiation complex, including the dynamic conformations and spatial arrangements of DnaA subcomplexes.

  20. Fire testing of bare uranium hexafluoride cylinders

    Energy Technology Data Exchange (ETDEWEB)

    Pryor, W.A. [PAI Corp., Oak Ridge, TN (United States)

    1991-12-31

    In 1965, the Oak Ridge Gaseous Diffusion Plant (ORGDP), now the K-25 Site, conducted a series of tests in which bare cylinders of uranium hexafluoride (UF{sub 6}) were exposed to engulfing oil fires for the US Atomic Energy Commission (AEC), now the US Department of Energy (DOE). The tests are described and the results, conclusions, and observations are presented. Two each of the following types of cylinders were tested: 3.5-in.-diam {times} 7.5-in.-long cylinders of Monel (Harshaw), 5.0-in.-diam {times} x 30-in.-long cylinders of Monel, and 8-in.-diam {times} 48-in.-long cylinders of nickel. The cylinders were filled approximately to the standard UF{sub 6} fill limits of 5, 55, and 250 lb, respectively, with a U-235 content of 0.22%. The 5-in.- and 8-in.-diam cylinders were tested individually with and without their metal valve covers. For the 3.5-in.-diam Harshaw cylinders and the 5.0-in.-diam cylinder without a valve cover, the valves failed and UF{sub 6} was released. The remaining 6 cylinders ruptured explosively in time intervals ranging from about 8.5 to 11 min.

  1. Fire testing of bare uranium hexafluoride cylinders

    Energy Technology Data Exchange (ETDEWEB)

    Pryor, W.A. [PAI Corp., Oak Rige, TN (United States)

    1991-12-31

    In 1965, the Oak Ridge Gaseous Diffusion Plant (ORGDP), now the K-25 Site, conducted a series of tests in which bare cylinders of uranium hexafluoride (UF{sub 6}) were exposed to engulfing oil fires for the US Atomic Energy Commission (AEC), now the US Department of Energy (DOE). The tests are described and the results, conclusions, and observations are presented. Two each of the following types of cylinders were tested: 3.5-in.-diam {times} 7.5-in.-long cylinders of Monel (Harshaw), 5.0-in.-diam {times} 30-in.-long cylinders of Monel, and 8-in.-diam {times} 48-in.-long cylinders of nickel. The cylinders were filled approximately to the standard UF{sub 6} fill limits of 5, 55, and 250 lb, respectively, with a U-235 content of 0.22%. The 5-in.- and 8-in.-diam cylinders were tested individually with and without their metal valve covers. For the 3.5-in.-diam Harshaw cylinders and the 5.0-in.-diam cylinder without a valve cover the valves failed and UF{sub 6} was released. The remaining cylinders ruptured explosively in time intervals ranging from about 8.5 to 11 min.

  2. Caledon Propane first to import composite cylinders

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    2007-11-15

    The Ontario-based company Caledon Transport will be the first company in Canada to import lightweight fiberglass propane cylinders. The Ragasco liquid propane gas (LPG) cylinder is constructed from non-metallic composite materials in 3 different layers. The thermoplastic single-piece layer provides a gas barrier, while the composite layer on the outside of the cylinder is reinforced with continuous fiberglass and resin. The outer casing was designed to provide impact protection for the pressure cylinder and valve. At 18 pounds, the lightweight cylinder is only 18.9 inches high and 12.1 inches in diameter. The propane level is visible at all times. The cylinder was constructed to provide improved stacking and lifting advantages for both customers and gas company employees. 2 figs.

  3. Cylinder valve packing nut studies

    Energy Technology Data Exchange (ETDEWEB)

    Blue, S.C. [Martin Marietta Energy Systems, Inc., Paducah, KY (United States)

    1991-12-31

    The design, manufacture, and use of cylinder valve packing nuts have been studied to improve their resistance to failure from stress corrosion cracking. Stress frozen photoelastic models have been analyzed to measure the stress concentrations at observed points of failure. The load effects induced by assembly torque and thermal expansion of stem packing were observed by strain gaging nuts. The effects of finishing operations and heat treatment were studied by the strain gage hole boring and X-ray methods. Modifications of manufacturing and operation practices are reducing the frequency of stress corrosion failures.

  4. DNA nanotechnology for nucleic acid analysis: multifunctional molecular DNA machine for RNA detection.

    Science.gov (United States)

    Cox, A J; Bengtson, H N; Rohde, K H; Kolpashchikov, D M

    2016-12-06

    The Nobel prize in chemistry in 2016 was awarded for 'the design and synthesis of molecular machines'. Here we designed and assembled a molecular machine for the detection of specific RNA molecules. An association of several DNA strands, named multifunctional DNA machine for RNA analysis (MDMR1), was designed to (i) unwind RNA with the help of RNA-binding arms, (ii) selectively recognize a targeted RNA fragment, (iii) attract a signal-producing substrate and (iv) amplify the fluorescent signal by catalysis. MDMR1 enabled detection of 16S rRNA at concentrations ∼24 times lower than that by a traditional deoxyribozyme probe.

  5. Transient Magnetic Field in a Conducting Cylinder

    Directory of Open Access Journals (Sweden)

    Zygmunt Piatek

    2004-01-01

    Full Text Available In the paper we determine the transient magnetic field in a conducting cylinder placed in external longitudinal sine-shaped magnetic field using the solution of Bessell equation in cylindrical co-ordinates, and also applying integral Laplace transformations, attenuation and diffusion of the magnetic field strength in the cylinder. The resulting equations can be used to describe volume density of the power lost in the cylinder and to determine substitute parameters of the inductor-cylindrical work system.

  6. Accidental death resulting from acetylene cylinder impact.

    Science.gov (United States)

    Rani, Mukta; Gupta, Avneesh; Dikshit, P C; Aggrawal, Anil; Setia, Puneet; Dhankar, Vijay

    2005-06-01

    Acetylene is an inflammable gas commonly used for welding in small-scale industries. We present a case of a 34-year-old male welder who died following injuries sustained from explosion of an acetylene gas-welding cylinder. In this case report, we discuss the circumstances leading to the explosion of the welding cylinder, the autopsy findings, and a brief review of the literature on deaths resulting from blasts of acetylene cylinders.

  7. A transcription fork model for Pol IV and Pol V-dependent RNA-directed DNA methylation.

    Science.gov (United States)

    Pikaard, C S; Haag, J R; Pontes, O M F; Blevins, T; Cocklin, R

    2012-01-01

    In Arabidopsis thaliana, nuclear multisubunit RNA polymerase IV (Pol IV) and RNA-DEPENDENT RNA POLYMERASE 2 (RDR2) are required for the biogenesis of 24-nucleotide small interfering RNAs (siRNAs) that direct DNA methylation and transcriptional silencing at target loci transcribed by nuclear multisubunit RNA polymerase V (Pol V). Pol IV and RDR2 physically associate and RDR2's polymerase activity in vitro is dependent on Pol IV. RDR2 transcription of nascent Pol IV transcripts might result in discontinuous second strands, analogous to lagging-strand Okazaki fragments generated during DNA replication. In vitro, Pol V is unable to displace nontemplate DNA during transcriptional elongation. This suggests a need for DNA duplex unwinding by helper proteins, perhaps analogous to the helicase-mediated duplex unwinding that occurs at replication forks to enable leading strand synthesis by DNA polymerase ε. A multiprotein complex (DRD1, DMS3, DMS11, RDM1) known to enable Pol V transcription might facilitate duplex unwinding via ATP-dependent DNA translocase, single-stranded DNA binding, and cohesin-like strand capture activities. These considerations are discussed and incorporated into a "transcription fork" model for Pol IV and Pol V-dependent RNA-directed DNA methylation.

  8. Fire exposure of empty 30B cylinders

    Energy Technology Data Exchange (ETDEWEB)

    Ziehlke, K.T. [MJB Technical Associates, Inc., Knoxville, TN (United States)

    1991-12-31

    Cylinders for UF{sub 6} handling, transport, and storage are designed and built as unfired pressure vessels under ASME Boiler and Pressure Vessel Code criteria and standards. They are normally filled and emptied while UF{sub 6} is in its liquid phase. Transport cylinders such as the Model 30B are designed for service at 200 psi and 250{degrees}F, to sustain the process conditions which prevail during filling or emptying operations. While in transport, however, at ambient temperature the UF{sub 6} is solid, and the cylinder interior is well below atmospheric pressure. When the cylinders contain isotopically enriched product (above 1.0 percent U-235), they are transported in protective overpacks which function to guard the cylinders and their contents against thermal or mechanical damage in the event of possible transport accidents. Two bare Model 30B cylinders were accidentally exposed to a storage warehouse fire in which a considerable amount of damage was sustained by stored materials and the building structure, as well as by the cylinder valves and valve protectors. The cylinders were about six years old, and had been cleaned, inspected, hydrotested, and re-certified for service, but were still empty at the time of the fire. The privately-owned cylinders were transferred to DOE for testing and evaluation of the fire damage.

  9. Optimization and improvement of Halbach cylinder design

    DEFF Research Database (Denmark)

    Bjørk, Rasmus; Bahl, Christian Robert Haffenden; Smith, Anders

    2008-01-01

    In this paper we describe the results of a parameter survey of a 16 segmented Halbach cylinder in three dimensions in which the parameters internal radius, rin, external radius, rex, and length, L, have been varied. Optimal values of rex and L were found for a Halbach cylinder with the least...... that this parameter was optimal for long Halbach cylinders with small rex. Using the previously mentioned additional blocks of magnets can improve the parameter by as much as 15% as well as improve the homogeneity of the field in the cylinder bore. ©2008 American Institute of Physics...

  10. The Permeability of Boolean Sets of Cylinders

    Directory of Open Access Journals (Sweden)

    Willot F.

    2016-07-01

    Full Text Available Numerical and analytical results on the permeability of Boolean models of randomly-oriented cylinders with circular cross-section are reported. The present work investigates cylinders of prolate (highly-elongated and oblate (nearly flat types. The fluid flows either inside or outside of the cylinders. The Stokes flow is solved using full-fields Fourier-based computations on 3D binarized microstructures. The permeability is given for varying volume fractions of pores. A new upper-bound is derived for the permeability of the Boolean model of oblate cylinders. The behavior of the permeability in the dilute limit is discussed.

  11. Inner cylinder of the CMS vacuum tank.

    CERN Document Server

    Patrice Loïez

    2002-01-01

    The vacuum tank of the CMS magnet system consists of inner and outer stainless-steel cylinders and houses the superconducting coil. The inner cylinder contains all the barrel sub-detectors, which it supports via a system of horizontal rails. The cylinder is pictured here in the vertical position on a yellow platform mounted on the ferris-wheel support structure. This will allow it to be pivoted and inserted into the outer cylinder already attached to the innermost ring of the barrel yoke.

  12. Overseas shipments of 48Y cylinders

    Energy Technology Data Exchange (ETDEWEB)

    Tanaka, R.T.; Furlan, A.S. [Cameco Corp., Port Hope, Ontario (Canada)

    1991-12-31

    This paper describes experiences with two incidents of overseas shipments of uranium hexafluoride (UF{sub 6}) cylinders. The first incident involved nine empty UF{sub 6} cylinders in enclosed sea containers. Three UF{sub 6} cylinders broke free from their tie-downs and damaged and contaminated several sea containers. This paper describes briefly how decontamination was carried out. The second incident involved a shipment of 14 full UF{sub 6} cylinders. Although the incident did not cause an accident, the potential hazard was significant. The investigation of the cause of the near accident is recounted. Recommendations to alleviate future similar incidents for both cases are presented.

  13. Swap your propane cylinder with SWOP

    International Nuclear Information System (INIS)

    Anon.

    1997-01-01

    A very successful propane cylinder exchange program operated by South Western Ontario Propane (SWOP) Inc., was described. The company specializes in propane cylinder exchange and in the refurbishing and marketing of top quality domestic and commercial propane cylinders. The company, currently operating out of Bradford, Ontario, was started in 1991. It employs a staff of 25 in peak season. It has some 200 exchange outlets throughout Ontario and has accepted outdated tanks from as far west as Manitoba and as far east as Quebec. A typical transaction involves bringing an empty cylinder to the nearest SWOP location and exchanging it for a full SWOP cylinder. SWOP does about 50,000 to 60,000 exchanges a year. For the consumer, the program is said to be cheaper, safer and more convenient than getting refills. As far as dealers are concerned operating a SWOP exchange outlet can add extra profits, attract new customers, and build additional consumer loyalty without the need for extra staff or additional indoor space. SWOP delivers full cylinders to exchange outlets on a weekly basis when it also picks up the empty cylinders. At dealer locations, the cylinders (full or empty) are stored in company -designed vandal-proof metal cages. Major expansion of the network of outlets and the cylinder refurbishing and refilling facilities are planned for 1998

  14. Internal combustion engine cylinder-to-cylinder balancing with balanced air-fuel ratios

    Science.gov (United States)

    Harris, Ralph E.; Bourn, Gary D.; Smalley, Anthony J.

    2006-01-03

    A method of balancing combustion among cylinders of an internal combustion engine. For each cylinder, a normalized peak firing pressure is calculated as the ratio of its peak firing pressure to its combustion pressure. Each cylinder's normalized peak firing pressure is compared to a target value for normalized peak firing pressure. The fuel flow is adjusted to any cylinder whose normalized peak firing pressure is not substantially equal to the target value.

  15. Determination of physical adsorption loss of primary standard gas mixtures in cylinders using cylinder-to-cylinder division

    Science.gov (United States)

    Lee, Sangil; Eon Kim, Mi; Hyub Oh, Sang; Seog Kim, Jin

    2017-12-01

    Primary standard gas mixtures (PSMs) are typically prepared in cylinders and the amount-of-substance fractions are determined by purity analysis and gravimetric method. However, the actual amount-of-substance fraction can be different from the gravimetrically determined value due to adsorption loss onto the internal surface of cylinders. The resulted difference due to the adsorption loss can be larger than the PSM uncertainty. In this study, the cylinder-to-cylinder division method is proposed to evaluate any potential physical adsorption loss onto the internal surface of cylinders. A method for estimating the amount of adsorption loss, the corrected amount-of-substance fraction and its uncertainty due to the adsorption loss is described.

  16. Flexural vibrations of finite composite poroelastic cylinders

    Indian Academy of Sciences (India)

    infinite hollow poroelastic cylinders. Axially symmetric vibrations of finite composite poroe- lastic cylinders that are bonded end to end are investigated by Shah & Tajuddin (2009). The analysis of the flexural vibrations in cylindrical structures has wide applications in the field of acoustics structural design and Biomechanics, ...

  17. Topping pressure for gas-storage cylinders

    Science.gov (United States)

    Haben, R. L.

    1979-01-01

    With charts derived from gas-storage system model, required topping pressure can be determined from initial cylinder pressure and temperature of gas entering cylinder. Charts are available for hydrogen and oxygen and can be developed for other important industrial gases as well.

  18. On certain geodesic conjugacies of flat cylinders

    Indian Academy of Sciences (India)

    We prove C 0 -conjugacy rigidity of any flat cylinder among two different classes of metrics on the cylinder, namely among the class of rotationally symmetric metrics and among the class of metrics without conjugate points. Author Affiliations. C S ARAVINDA1 H A GURURAJA2. TIFR Centre for Applicable Mathematics, P.O. ...

  19. Longitudinal shear vibrations of composite poroelastic cylinders ...

    African Journals Online (AJOL)

    Employing Biot's theory of wave propagation in liquid saturated porous media, longitudinal shear vibrations of composite poroelastic cylinders of infinite extent are investigated. The composite poroelastic cylinder is made of two different poroelastic materials. The dilatations of liquid and solid media are zero, hence liquid ...

  20. NUMERICAL STUDY OF NATURAL CONVECTION FROM TWO PARALLEL HORIZONTAL CYLINDERS ENCLOSED BY CIRCULAR CYLINDER

    Directory of Open Access Journals (Sweden)

    Mahmood Husain Ali

    2013-05-01

    Full Text Available In this paper, numerical solution is presented for the steady state, two dimensional natural convection heat transfer from two parallel horizontal cylinders enclosed by circular cylinder. The inner cylinders are heated and maintained at constant surface temperature, while the outer cylinder is cooled at constant surface temperature. Boundary fitted coordinate system is used to solve governing equations. The vorticity-stream function and energy equations is solved using explicit finite deference method and stream function equation solved by successive iteration method. (20Deferent cases are studied cover rang of Rayleigh number from (1,000 to (25,000 based on the inner cylinder diameter. These cases study the effect of the  varying inner cylinders position horizontally and vertically within outer cylinder on the heat transfer and buoyancy that causes the flow. Outputs are displayed in terms of streamline, isothermal contours and local and average Nusselt number. The results showed that the position of the inner cylinders highly affects the heat transfer and flow movements in the gap. At low Rayleigh numbers the average Nusselt number increases with increase of horizontal distance between inner cylinders but the state is reversed at high Rayleigh numbers, while the average Nusselt number is increases with inner cylinder moving down at all Rayleigh numbers. The optimal position of inner cylinders for maximum and minimum heat transfer is located at each Rayleigh number so can be employed in isolation process or cooling process.

  1. Rewinding Frankenstein and the body-machine: organ transplantation in the dystopian young adult fiction series Unwind.

    Science.gov (United States)

    Wohlmann, Anita; Steinberg, Ruth

    2016-12-01

    While the separation of body and mind (and the entailing metaphor of the body as a machine) has been a cornerstone of Western medicine for a long time, reactions to organ transplantation among others challenge this clear-cut dichotomy. The limits of the machine-body have been negotiated in science fiction, most canonically in Mary Shelley's Frankenstein (1818). Since then, Frankenstein's monster itself has become a motif that permeates both medical and fictional discourses. Neal Shusterman's contemporary dystology for young adults, Unwind, draws on traditional concepts of the machine-body and the Frankenstein myth. This article follows one of the young protagonists in the series, who is entirely constructed from donated tissue, and analyses how Shusterman explores the complicated relationship between body and mind and between self and other as the teenager matures into an adult. It will be shown that, by framing the story of a transplanted individual along the lines of a coming-of-age narrative, Shusterman inter-relates the acceptance of a donor organ with the transitional space of adolescence and positions the quest for embodied selfhood at the centre of both developments. By highlighting the interconnections between medical discourse and a literary tradition, the potential contribution of the series to the treatment and understanding of post-transplant patients will be addressed. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

  2. The Barley stripe mosaic virus γb protein promotes chloroplast-targeted replication by enhancing unwinding of RNA duplexes.

    Directory of Open Access Journals (Sweden)

    Kun Zhang

    2017-04-01

    Full Text Available RNA viruses encode various RNA binding proteins that function in many steps of viral infection cycles. These proteins function as RNA helicases, methyltransferases, RNA-dependent RNA polymerases, RNA silencing suppressors, RNA chaperones, movement proteins, and so on. Although many of the proteins bind the viral RNA genome during different stages of infection, our knowledge about the coordination of their functions is limited. In this study, we describe a novel role for the Barley stripe mosaic virus (BSMV γb as an enhancer of αa RNA helicase activity, and we show that the γb protein is recruited by the αa viral replication protein to chloroplast membrane sites of BSMV replication. Mutagenesis or deletion of γb from BSMV resulted in reduced positive strand (+ RNAα accumulation, but γb mutations abolishing viral suppressor of RNA silencing (VSR activity did not completely eliminate genomic RNA replication. In addition, cis- or trans-expression of the Tomato bushy stunt virus p19 VSR protein failed to complement the γb replication functions, indicating that the direct involvement of γb in BSMV RNA replication is independent of VSR functions. These data support a model whereby two BSMV-encoded RNA-binding proteins act coordinately to regulate viral genome replication and provide new insights into strategies whereby double-stranded viral RNA unwinding is regulated, as well as formation of viral replication complexes.

  3. The Barley stripe mosaic virus γb protein promotes chloroplast-targeted replication by enhancing unwinding of RNA duplexes

    Science.gov (United States)

    Yang, Meng; Liu, Songyu; Li, Zhenggang; Wang, Xianbing; Han, Chenggui; Yu, Jialin

    2017-01-01

    RNA viruses encode various RNA binding proteins that function in many steps of viral infection cycles. These proteins function as RNA helicases, methyltransferases, RNA-dependent RNA polymerases, RNA silencing suppressors, RNA chaperones, movement proteins, and so on. Although many of the proteins bind the viral RNA genome during different stages of infection, our knowledge about the coordination of their functions is limited. In this study, we describe a novel role for the Barley stripe mosaic virus (BSMV) γb as an enhancer of αa RNA helicase activity, and we show that the γb protein is recruited by the αa viral replication protein to chloroplast membrane sites of BSMV replication. Mutagenesis or deletion of γb from BSMV resulted in reduced positive strand (+) RNAα accumulation, but γb mutations abolishing viral suppressor of RNA silencing (VSR) activity did not completely eliminate genomic RNA replication. In addition, cis- or trans-expression of the Tomato bushy stunt virus p19 VSR protein failed to complement the γb replication functions, indicating that the direct involvement of γb in BSMV RNA replication is independent of VSR functions. These data support a model whereby two BSMV-encoded RNA-binding proteins act coordinately to regulate viral genome replication and provide new insights into strategies whereby double-stranded viral RNA unwinding is regulated, as well as formation of viral replication complexes. PMID:28388677

  4. Coupled electromechanical model of an imperfect piezoelectric vibrating cylinder gyroscope

    CSIR Research Space (South Africa)

    Loveday, PW

    1996-01-01

    Full Text Available Coupled electromechanical equations of motion, describing the dynamics of a vibrating cylinder gyroscope, are derived using Hamilton's principle and the Rayleigh-Ritz method. The vibrating cylinder gyroscope comprises a thin walled steel cylinder...

  5. Brachistochrone curve of a fluid filled cylinder

    Science.gov (United States)

    Sarma, Srikanth; Raja, Sharan; Mahapatra, Pallab Sinha; Panchangnula, Mahesh

    2017-11-01

    The brachistochrone curve for a non-dissipative particle tries to maximize inertia of the particle but for a fluid filled cylinder, increasing inertia would amount to high dissipative losses. Hence the trade off between inertia and dissipation plays a vital role in the dynamics of a fluid filled cylinder. This trade off manifests itself in the form of an integro-differential equation governing the angular acceleration of the cylinder. Here, we compute the brachistochrone curve using optimal control principles and investigate the effect of the fore mentioned trade off on the deviation of the brachistochrone curve from that of a non-dissipative particle. Also, we investigate the effects of the non-dimensional parameters of the problem on the shape of the brachistochrone curve. We analyze the dissipation rate during the cylinder's motion and show that energy based arguments don't hold good for a fluid filled cylinder. We then analyze the stability of the time varying fluid flow in the cylinder and find an admissible region for the terminal point which would ensure the stability of the fluid flow as the cylinder rolls over the brachistochrone curve.

  6. Dynamical instability of a charged gaseous cylinder

    Science.gov (United States)

    Sharif, M.; Mumtaz, Saadia

    2017-10-01

    In this paper, we discuss dynamical instability of a charged dissipative cylinder under radial oscillations. For this purpose, we follow the Eulerian and Lagrangian approaches to evaluate linearized perturbed equation of motion. We formulate perturbed pressure in terms of adiabatic index by applying the conservation of baryon numbers. A variational principle is established to determine characteristic frequencies of oscillation which define stability criteria for a gaseous cylinder. We compute the ranges of radii as well as adiabatic index for both charged and uncharged cases in Newtonian and post-Newtonian limits. We conclude that dynamical instability occurs in the presence of charge if the gaseous cylinder contracts to the radius R*.

  7. Flow induced by a skewed vortex cylinder

    DEFF Research Database (Denmark)

    Branlard, Emmanuel Simon Pierre

    2017-01-01

    The velocity field induced by a skewed vortex cylinder of longitudinal and tangential vorticity is derived in this chapter by direct integration of the Biot– Savart law. The derivation steps are provided in details. The results of Castles and Durham for the skewed semi-infinite cylinder....... The content of this chapter is based on the publication of the author entitled "Cylindrical vortex wake model: skewed cylinder, application to yawed or tilted rotors" [1]. Results from this chapter are applied: in Chap. 21 to model a wind turbine (or rotor) in yaw, in Chap. 22 to derive a new yaw...

  8. Multi-cylinder hot gas engine

    Science.gov (United States)

    Corey, John A.

    1985-01-01

    A multi-cylinder hot gas engine having an equal angle, V-shaped engine block in which two banks of parallel, equal length, equally sized cylinders are formed together with annular regenerator/cooler units surrounding each cylinder, and wherein the pistons are connected to a single crankshaft. The hot gas engine further includes an annular heater head disposed around a central circular combustor volume having a new balanced-flow hot-working-fluid manifold assembly that provides optimum balanced flow of the working fluid through the heater head working fluid passageways which are connected between each of the cylinders and their respective associated annular regenerator units. This balanced flow provides even heater head temperatures and, therefore, maximum average working fluid temperature for best operating efficiency with the use of a single crankshaft V-shaped engine block.

  9. Theory of interacting dislocations on cylinders.

    Science.gov (United States)

    Amir, Ariel; Paulose, Jayson; Nelson, David R

    2013-04-01

    We study the mechanics and statistical physics of dislocations interacting on cylinders, motivated by the elongation of rod-shaped bacterial cell walls and cylindrical assemblies of colloidal particles subject to external stresses. The interaction energy and forces between dislocations are solved analytically, and analyzed asymptotically. The results of continuum elastic theory agree well with numerical simulations on finite lattices even for relatively small systems. Isolated dislocations on a cylinder act like grain boundaries. With colloidal crystals in mind, we show that saddle points are created by a Peach-Koehler force on the dislocations in the circumferential direction, causing dislocation pairs to unbind. The thermal nucleation rate of dislocation unbinding is calculated, for an arbitrary mobility tensor and external stress, including the case of a twist-induced Peach-Koehler force along the cylinder axis. Surprisingly rich phenomena arise for dislocations on cylinders, despite their vanishing Gaussian curvature.

  10. Investigations of Flow past Spinning Cylinders

    Science.gov (United States)

    Mehmedagic, Igbal; Carlucci, Pasquale; Buckley, Liam; Carlucci, Donald; Aljallis, Elias; Thangam, Siva

    2013-11-01

    A subsonic wind tunnel is used to perform experiments on flow past spinning cylinders. The blunt cylinders are sting-mounted and oriented such that their axis of rotation is aligned with the mean flow. The experiments cover a Reynolds number range of up to 300000 and rotation numbers of up to 1.2 (based on cylinder diameter). The results for spinning cylinders with both rear-mounted and fore-mounted stings are presented. Computations are performed using a two-equation anisotropic turbulence model that is based on proper representation of the energy spectrum to capture rotation and curvature. The model performance is validated with benchmark experimental flows and implemented for analyzing the flow configuration used in the experimental study. Funded in part by U. S. Army, ARDEC.

  11. Experimental Investigations of Flow past Spinning Cylinders

    Science.gov (United States)

    Carlucci, Pasquale; Buckley, Liam; Mehmedagic, Igbal; Carlucci, Donald; Thangam, Siva

    2015-11-01

    Experimental investigations of flow past spinning cylinders is presented in the context of their application and relevance to flow past projectiles. A subsonic wind tunnel is used to perform experiments on flow past spinning cylinders that are sting-mounted and oriented such that their axis of rotation is aligned with the mean flow. The experiments cover a Reynolds number range of up to 300000 and rotation numbers of up to 2 (based on cylinder diameter). The experimental validation of the tunnel characteristics and the benchmarking of the flow field in the tunnel are described. The experimental results for spinning cylinders with both rear-mounted and fore-mounted stings are presented along with available computational and experimental findings. This work was funded in part by U. S. Army ARDEC.

  12. Origins of DNA Replication and Amplification in the Breast Cancer Genome

    Science.gov (United States)

    2013-09-01

    somatic mutations or other genomic changes. We wish to ask if a genomic change (genetic or epigenetic) might produce novel binding site(s) for the...bacteriophages, animal viruses , and unicellular eukaryotes studied thus far have high AT content, presumably to facilitate unwinding of the DNA. Task (3...have the GC skew, which is more consistent with the base composition of replication origins from bacteria, viruses and yeast.  Performed

  13. Helicase and polymerase move together close to the fork junction and copy DNA in one-nucleotide steps

    Science.gov (United States)

    Pandey, Manjula; Patel, Smita S.

    2014-01-01

    SUMMARY By simultaneously measuring DNA synthesis and dNTP hydrolysis, we show that T7 DNA polymerase and T7 gp4 helicase move in sync during leading strand synthesis taking one-nucleotide steps and hydrolyzing one dNTP per base-pair unwound-copied. The cooperative catalysis enables the helicase and polymerase to move at a uniformly fast rate without GC-dependency or idling with futile NTP hydrolysis. We show that the helicase and polymerase are located close to the replication fork junction. This architecture enables the polymerase to use its strand-displacement synthesis to increase the unwinding rate while the helicase aids this process by translocating along single-stranded DNA and trapping the unwound bases. Thus, in contrast to the helicase-only unwinding model, our results suggest a new model where the helicase and polymerase are moving in one-nucleotide steps and DNA synthesis drives fork unwinding and a role of the helicase is to trap the unwound bases and prevent DNA reannealing. PMID:24630996

  14. Helicase and Polymerase Move Together Close to the Fork Junction and Copy DNA in One-Nucleotide Steps

    Directory of Open Access Journals (Sweden)

    Manjula Pandey

    2014-03-01

    Full Text Available By simultaneously measuring DNA synthesis and dNTP hydrolysis, we show that T7 DNA polymerase and T7 gp4 helicase move in sync during leading-strand synthesis, taking one-nucleotide steps and hydrolyzing one dNTP per base-pair unwound/copied. The cooperative catalysis enables the helicase and polymerase to move at a uniformly fast rate without guanine:cytosine (GC dependency or idling with futile NTP hydrolysis. We show that the helicase and polymerase are located close to the replication fork junction. This architecture enables the polymerase to use its strand-displacement synthesis to increase the unwinding rate, whereas the helicase aids this process by translocating along single-stranded DNA and trapping the unwound bases. Thus, in contrast to the helicase-only unwinding model, our results suggest a model in which the helicase and polymerase are moving in one-nucleotide steps, DNA synthesis drives fork unwinding, and a role of the helicase is to trap the unwound bases and prevent DNA reannealing.

  15. W-76 PBX 9501 cylinder tests

    Energy Technology Data Exchange (ETDEWEB)

    Hill, L.G.; Catanach, R.A.

    1998-07-01

    Five 1-inch diameter cylinder tests were fired in support of the W-76 high explosive surveillance program. Three of the tests used baseline material, and two used stockpile return material. The diagnostics were electrical pins to measure detonation velocity and a streak camera to measure wall motion. The data was analyzed for cylinder energy, Gurney energy, and detonation velocity. The results of all three measures were consistent for all five tests, to within the experimental accuracy.

  16. Dynamic Fracture Simulations of Explosively Loaded Cylinders

    Energy Technology Data Exchange (ETDEWEB)

    Arthur, Carly W. [Univ. of California, Davis, CA (United States). Dept. of Civil and Environmental Engineering; Goto, D. M. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2015-11-30

    This report documents the modeling results of high explosive experiments investigating dynamic fracture of steel (AerMet® 100 alloy) cylinders. The experiments were conducted at Lawrence Livermore National Laboratory (LLNL) during 2007 to 2008 [10]. A principal objective of this study was to gain an understanding of dynamic material failure through the analysis of hydrodynamic computer code simulations. Two-dimensional and three-dimensional computational cylinder models were analyzed using the ALE3D multi-physics computer code.

  17. Multiple Cylinder Free-Piston Stirling Machinery

    Science.gov (United States)

    Berchowitz, David M.; Kwon, Yong-Rak

    In order to improve the specific power of piston-cylinder type machinery, there is a point in capacity or power where an advantage accrues with increasing number of piston-cylinder assemblies. In the case of Stirling machinery where primary energy is transferred across the casing wall of the machine, this consideration is even more important. This is due primarily to the difference in scaling of basic power and the required heat transfer. Heat transfer is found to be progressively limited as the size of the machine increases. Multiple cylinder machines tend to preserve the surface area to volume ratio at more favorable levels. In addition, the spring effect of the working gas in the so-called alpha configuration is often sufficient to provide a high frequency resonance point that improves the specific power. There are a number of possible multiple cylinder configurations. The simplest is an opposed pair of piston-displacer machines (beta configuration). A three-cylinder machine requires stepped pistons to obtain proper volume phase relationships. Four to six cylinder configurations are also possible. A small demonstrator inline four cylinder alpha machine has been built to demonstrate both cooling operation and power generation. Data from this machine verifies theoretical expectations and is used to extrapolate the performance of future machines. Vibration levels are discussed and it is argued that some multiple cylinder machines have no linear component to the casing vibration but may have a nutating couple. Example applications are discussed ranging from general purpose coolers, computer cooling, exhaust heat power extraction and some high power engines.

  18. Maximal liquid bridges between horizontal cylinders

    Science.gov (United States)

    Huppert, Herbert E.; Neufeld, Jerome A.

    2016-01-01

    We investigate two-dimensional liquid bridges trapped between pairs of identical horizontal cylinders. The cylinders support forces owing to surface tension and hydrostatic pressure that balance the weight of the liquid. The shape of the liquid bridge is determined by analytically solving the nonlinear Laplace–Young equation. Parameters that maximize the trapping capacity (defined as the cross-sectional area of the liquid bridge) are then determined. The results show that these parameters can be approximated with simple relationships when the radius of the cylinders is small compared with the capillary length. For such small cylinders, liquid bridges with the largest cross-sectional area occur when the centre-to-centre distance between the cylinders is approximately twice the capillary length. The maximum trapping capacity for a pair of cylinders at a given separation is linearly related to the separation when it is small compared with the capillary length. The meniscus slope angle of the largest liquid bridge produced in this regime is also a linear function of the separation. We additionally derive approximate solutions for the profile of a liquid bridge, using the linearized Laplace–Young equation. These solutions analytically verify the above-mentioned relationships obtained for the maximization of the trapping capacity. PMID:27616922

  19. 30 CFR 57.16006 - Protection of gas cylinder valves.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Protection of gas cylinder valves. 57.16006... Storage and Handling § 57.16006 Protection of gas cylinder valves. Valves on compressed gas cylinders shall be protected by covers when being transported or stored, and by a safe location when the cylinders...

  20. 30 CFR 56.16006 - Protection of gas cylinder valves.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Protection of gas cylinder valves. 56.16006... Storage and Handling § 56.16006 Protection of gas cylinder valves. Valves on compressed gas cylinders shall be protected by covers when being transported or stored, and by a safe location when the cylinders...

  1. Results of ultrasonic testing evaluations on UF6 storage cylinders

    International Nuclear Information System (INIS)

    Lykins, M.L.

    1997-02-01

    The three site cylinder management program is responsible for the safe storage of the DOE owned UF 6 storage cylinders at PORTS, PGDP and at the K-25 site. To ensure the safe storage of the UF 6 in the cylinders, the structural integrity of the cylinders must be evaluated. This report represents the latest cylinder integrity investigation that utilized wall thickness evaluations to identify thinning due to atmospheric exposure

  2. Molecular models for DNA damaged by photoreaction

    International Nuclear Information System (INIS)

    Pearlman, D.A.; Holbrook, S.R.; Pirkle, D.H.; Kim, S.H.

    1985-01-01

    Structural models of a DNA molecule containing a radiation-induced psoralen cross-link and of a DNA containing a thymine photodimer were constructed by applying energy-minimization techniques and model-building procedures to data from x-ray crystallographic studies. The helical axes of the models show substantial kinking and unwinding at the sites of the damage, which may have long-range as well as local effects arising from the concomitant changes in the supercoiling and overall structure of the DNA. The damaged areas may also serve as recognition sites for repair enzymes. These results should help in understanding the biologic effects of radiation-induced damage on cells

  3. Resistance to DNA denaturation in irradiated Chinese hamster V79 fibroblasts is linked to cell shape

    International Nuclear Information System (INIS)

    Olive, P.L.; Vanderbyl, S.; MacPhail, S.H.

    1991-01-01

    Exponentially growing Chinese hamster V79-171b lung fibroblasts seeded at high density on plastic (approximately 7 x 10(3) cells/cm2) flatten, elongate, and produce significant amounts of extracellular fibronectin. When lysed in weak alkali/high salt, the rate of DNA denaturation following exposure to ionizing radiation is exponential. Conversely, cells plated at low density (approximately 7 x 10(2) cells/cm2) on plastic are more rounded 24 h later, produce little extracellular fibronectin, and display unusual DNA denaturation kinetics after X-irradiation. DNA in these cells resists denaturation, as though constraints to DNA unwinding have developed. Cell doubling time and distribution of cells in the growth cycle are identical for both high and low density cultures as is cell survival in response to radiation damage. The connection between DNA conformation and cell shape was examined further in low density cultures grown in conditioned medium. Under these conditions, cells at low density were able to elongate, and DNA denaturation of low density cultures was identical to that of high density cultures. Conversely, cytochalasin D, which interferes with actin polymerization causing cells to round up and release fibronectin, allowed development of constraints in high density cultures. These results suggest that DNA conformation is sensitive to changes in cell shape which result when cells are grown in different environments. However, these changes in DNA conformation detected by the DNA unwinding assay do not appear to play a direct role in radiation-induced cell killing

  4. Binding and interaction of di- and tri-substituted organometallic triptycene palladium complexes with DNA.

    Science.gov (United States)

    Kumari, Rina; Bhowmick, Sourav; Das, Neeladri; Das, Prolay

    2014-10-01

    Two triptycene-based ligands with pendant bromophenyl units have been prepared. These triptycene derivatives have been used as synthons for the synthesis of di and tri nuclear palladium complexes. The organic molecules and their corresponding organometallic complexes have been fully characterized using nuclear magnetic resonance (NMR), infrared (IR) spectroscopy and mass spectrometry. The mode of binding and effect of the complexes on pUC19 plasmid, calf thymus DNA and oligomer duplex DNA have been investigated by a host of analytical methods. The complexes brought about unwinding of supercoiled plasmid and the unwinding angle was found to be related to the binding affinity of the complexes with DNA, where both these parameters were guided by the structure of the complexes. Concentration-dependent inhibition of endonuclease activity of SspI and BamHI by the complexes indicates preference for G/C sequence for binding to DNA. However, neither the complexes did not introduce any cleavage at abasic site in oligomer duplex DNA, nor they created linear form of the plasmid upon co-incubation with the DNA samples. The interactions of the complexes with DNA were found to be strongly guided by the structure of the complexes, where intercalation as well as groove binding was observed, without inflicting any damage to the DNA. The mode of interaction of the complexes with DNA was further confirmed by isothermal calorimetry.

  5. Effect of longitudinal and transverse vibrations of an upstream square cylinder on vortex shedding behind two inline square cylinders

    International Nuclear Information System (INIS)

    Patil, Pratish P; Tiwari, Shaligram

    2009-01-01

    The characteristics of unsteady wakes behind a stationary square cylinder and another upstream vibrating square cylinder have been investigated numerically with the help of a developed computational code. The effect of longitudinal as well as transverse vibrations of the upstream cylinder is studied on the coupled wake between the two cylinders, which is found to control the vortex shedding behavior behind the downstream stationary cylinder. Computations are carried out for a fixed value of Reynolds number (Re = 200) and three different values of excitation frequencies of the upstream cylinder, namely less than, equal to and greater than the natural frequency of vortex shedding corresponding to flow past a stationary square cylinder. The vortex shedding characteristics of the unsteady wakes behind the vibrating and stationary cylinders are found to differ significantly for longitudinal and transverse modes of vibration of the upstream cylinder. The wake of the downstream stationary cylinder is found to depict a synchronization behavior with the upstream cylinder vibration. The spacing between the two cylinders has been identified to be the key parameter influencing the synchronization phenomenon. The effect of cylinder spacing on the wake synchronization and the hydrodynamic forces has been examined. In addition, a comparison of the drag forces for flow past transversely vibrating square and circular cylinders for similar amplitudes and frequencies of cylinder vibration has been presented while employing the tested computational code.

  6. Evaluation of impairment of DNA in marine gastropod, Morula granulata as a biomarker of marine pollution.

    Digital Repository Service at National Institute of Oceanography (India)

    Sarkar, A.; Bhagat, J.; Sarker, S.

    parameters measured in this assay were the amount of double-stranded (dsDNA), single stranded (ss-DNA) and the fraction of double-stranded remaining after alkaline unwinding (au-DNA) for a specified time under defined condition of pH and temperature. After... on ice to minimize endogenous damage occurring during slide preparation. The trypan blue exclusion test was used for viability assessment. 2.7. Comet assay The comet assay was performed according to the method described by Singh et al. (1988) with minor...

  7. Prediction of external corrosion for steel cylinders

    International Nuclear Information System (INIS)

    Lyon, B.F.

    1997-02-01

    The US Department of Energy (DOE) currently manages the UF 6 Cylinder Program (the program). The program was formed to address the depleted-uranium hexafluoride (UF 6 ) stored in approximately 50,000 carbon steel cylinders. The cylinders are located at three DOE sites: the K-25 site (K-25) at Oak Ridge, Tennessee; the Paducah Gaseous Diffusion Plant (PGDP) in Paducah, Kentucky, and the Portsmouth Gaseous Diffusion Plant (PORTS) in Portsmouth, Ohio. The System Requirements Document (SRD) (LMES 1996a) delineates the requirements of the program. The appropriate actions needed to fulfill these requirements are then specified within the System Engineering Management Plan (SEMP) (LMES 1996b). The report presented herein documents activities that in whole or in part satisfy specific requirements and actions stated in the UF 6 Cylinder Program SRD and SEMP with respect to forecasting cylinder conditions. The wall thickness projections made in this report are based on the assumption that the corrosion trends noted will continue. Some activities planned may substantially reduce the rate of corrosion, in which case the results presented here are conservative. The results presented here are intended to supersede those presented previously, as the quality of several of the datasets has improved

  8. Oscillatory Stokes Flow Past a Slip Cylinder

    Science.gov (United States)

    Palaniappan, D.

    2013-11-01

    Two-dimensional transient slow viscous flow past a circular cylinder with Navier slip boundary conditions is considered in the limit of low-Reynolds number. The oscillatory Stokes flow problem around a cylinder is solved using the stream function method leading to an analytic solution in terms of modified Bessel functions of the second kind. The corresponding steady-state behavior yields the familiar paradoxical result first detected by Stokes. It is noted that the two key parameters, viz., the frequency λ, and the slip coefficient ξ have a significant impact on the flow field in the vicinity of the cylinder contour. In the limit of very low frequency, the flow is dominated by a term containing a well-known biharmonic function found by Stokes that has a singular behavior at infinity. Local streamlines for small times show interesting flow patterns. Attached eddies due to flow separation - observed in the no-slip case - either get detached or pushed away from the cylinder surface as ξ is varied. Computed asymptotic results predict that the flow exhibits inviscid behavior far away from the cylinder in the frequency range 0 < λ << 1 . Although the frequency of oscillations is finite, our exact solutions reveal fairly rapid transitions in the flow domain. Research Enhancement grant, TAMUCC.

  9. UF{sub 6} cylinder fire test

    Energy Technology Data Exchange (ETDEWEB)

    Park, S.H. [Oak Ridge K-25 Site, Oak Ridge, TN (United States)

    1991-12-31

    With the increasing number of nuclear reactors for power generation, there is a comparable increase in the amount of UF{sub 6} being transported. Likewise, the probability of having an accident involving UF{sub 6}-filled cylinders also increases. Accident scenarios which have been difficult to assess are those involving a filled UF{sub 6} cylinder subjected to fire. A study is underway at the Oak Ridge K-25 Site, as part of the US DOE Enrichment Program, to provide empirical data and a computer model that can be used to evaluate various cylinder-in-fire scenarios. It is expected that the results will provide information leading to better handling of possible fire accidents as well as show whether changes should be made to provide different physical protection during shipment. The computer model being developed will be capable of predicting the rupture of various cylinder sizes and designs as well as the amount of UF{sub 6}, its distribution in the cylinder, and the conditions of the fire.

  10. Corrosion of breached UF6 storage cylinders

    International Nuclear Information System (INIS)

    Barber, E.J.; Taylor, M.S.; DeVan, J.H.

    1993-01-01

    This paper describes the corrosion processes that occurred following the mechanical failure of two steel 14-ton storage cylinders containing depleted UF 6 . The failures both were traced to small mechanical tears that occurred during stacking of the cylinders. Although subsequent corrosion processes greatly extended the openings in the wall. the reaction products formed were quite protective and prevented any significant environmental insult or loss of uranium. The relative sizes of the two holes correlated with the relative exposure times that had elapsed from the time of stacking. From the sizes and geometries of the two holes, together with analyses of the reaction products, it was possible to determine the chemical reactions that controlled the corrosion process and to develop a scenario for predicting the rate of hydrolysis of UF 6 , the loss rate of HF, and chemical attack of a breached UF 6 storage cylinder

  11. Stability of cylinder arrangement in potential flow

    International Nuclear Information System (INIS)

    Benaouicha, M.; Longatte, E.; Baj, F.

    2014-01-01

    Fluid-structure interaction and flow-induced vibration in square cylinder arrangement under incompressible, ideal and irrotational cross flow are investigated in the present paper. The purpose of this study is to contribute to better understanding of external fluid loads exerted on long thin cylinders inducing the flow perturbations. Indeed, in presence of high flow confinement, the thin cylinders could be subjected to strong vibrations, which may lead to instability development and therefore to a risk of break or collision. The dynamic instability of the mobile tube, according to some geometric and flow parameters such as reduced velocity and pitch ratio, is then studied. A semi-analytical approach is used to determine a stability criterion of the dynamical system. In addition, the influence of key physical parameters on fluid-solid dynamics interaction is quantified in the studied configuration. (authors)

  12. Free Vibration of Thick Multilayer Cylinders

    Directory of Open Access Journals (Sweden)

    H. R. Hamidzadeh

    1995-01-01

    Full Text Available In this study of the free vibration of multilayer thick cylinders, the medium is modeled by laminated linear viscoelastic cylinders of an infinite extent. The analytical modeling is based on three-dimensional wave propagation utilizing constant complex elastic moduli. The solution is achieved by determining the displacements and stresses for each interface and by complying with requirements at the interfaces. A propagator matrix relating the boundary displacements to boundary stresses is developed. Dimensionless natural frequencies and modal loss factors for different circumferential and axial wave numbers are determined. The validity of the proposed method is verified by comparing the results for one-, two-, and three-layer elastic cylinders with properties similar to those reported for an equivalent single layer.

  13. UF{sub 6} cylinder inspections at PGDP

    Energy Technology Data Exchange (ETDEWEB)

    Lamb, G.W.; Whinnery, W.N. [Martin Marietta Energy Systems, Inc., Paducah, KY (United States)

    1991-12-31

    Routine inspections of all UF{sub 6} cylinders at the Paducah Gaseous Diffusion Plant have been mandated by the Department of Energy. A specific UF{sub 6} cylinder inspection procedure for what items to inspect and training for the operators prior to inspection duty are described. The layout of the cylinder yards and the forms used in the inspections are shown. The large number of cylinders (>30,000) to inspect and the schedule for completion on the mandated time table are discussed. Results of the inspections and the actions to correct the deficiencies are explained. Future inspections and movement of cylinders for relocation of certain cylinder yards are defined.

  14. Evaluation of Concrete Cylinder Tests Using Finite Elements

    DEFF Research Database (Denmark)

    Saabye Ottosen, Niels

    1984-01-01

    Nonlinear axisymmetric finite element analyses are performed on the uniaxial compressive test of concrete cylinders. The models include thick steel loading plates, and cylinders with height‐to‐diameter ratios (h/d) ranging from 1‐3 are treated. A simple constitutive model of the concrete...... cylinders the strain softening is more pronounced along the surface of the cylinder middle, whereas longer cylinders exhibit a more uniform distribution of strain softening. The failure modes for force and displacement controlled tests are found to be similar. If long cylinders are to provide the true...

  15. Electromagnetic Invisibility of Elliptic Cylinder Cloaks

    International Nuclear Information System (INIS)

    Kan, Yao; Chao, Li; Fang, Li

    2008-01-01

    Structures with unique electromagnetic properties are designed based on the approach of spatial coordinate transformations of Maxwell's equations. This approach is applied to scheme out invisible elliptic cylinder cloaks, which provide more feasibility for cloaking arbitrarily shaped objects. The transformation expressions for the anisotropic material parameters and the field distribution are derived. The cloaking performances of ideal and lossy elliptic cylinder cloaks are investigated by finite element simulations. It is found that the cloaking performance will degrade in the forward direction with increasing loss. (fundamental areas of phenomenology (including applications))

  16. EC Hidraulic Drive Cylinder Relief Vlave Test

    Energy Technology Data Exchange (ETDEWEB)

    Wu, J.; /Fermilab

    1991-04-03

    This engineering note documents the testing of the set pressure of the EC hydraulic drive cylinder relief valve. The purpose of the relief valve is to provide a safety measure in the event that oil becomes trapped in the rod side of the cylinder and pressure is applied to the cap side. The note includes an explanation of the procedure used and a summary of the result of the testing done on February 14, 1991 by Gary Trotter. The result was that the cylinder relief valve relieved at the correct set pressure of 10,500 psig. The basic concern is for the protection of the cylinder. The pump is capable of providing up to 10,500 psi of pressure to either side of the cylinder. The cylinder is rated for 10,500 psi. Under normal operating conditions, the valves would be open, and the pumping pressure would automatically flow oil into one side, and remove oil from the other side. If, however, the valve for the other side was closed, so that oil could not be removed, then the pressure would build in that side. If the rod side is pressurized to the maximum pump pressure of 10,500 psi, the cross sectional area ratio of 2.29 results in a pressure of approximately 4600 psi in the cap side, which is well under the rated pressure. If, however, the cap side is pressurized to 10,500 psi, the cross sectional area would produce a pressure of approximately 24,000 psi in the rod side, which could damage the cylinder. Therefore, the pressure on the rod side must be limited to the rated pressure of 10,500 psi. In reality, the maximum operating force on the piston would be under 11,000 Ibs., which would result in the maximum cylinder pressure being under 8000 psi to the rod side, and under 3500 psi to the cap side. Therefore, the relief is only needed as a safety precaution in the case that oil becomes trapped.

  17. The bacterial DnaA-trio replication origin element specifies single-stranded DNA initiator binding.

    Science.gov (United States)

    Richardson, Tomas T; Harran, Omar; Murray, Heath

    2016-06-16

    DNA replication is tightly controlled to ensure accurate inheritance of genetic information. In all organisms, initiator proteins possessing AAA+ (ATPases associated with various cellular activities) domains bind replication origins to license new rounds of DNA synthesis. In bacteria the master initiator protein, DnaA, is highly conserved and has two crucial DNA binding activities. DnaA monomers recognize the replication origin (oriC) by binding double-stranded DNA sequences (DnaA-boxes); subsequently, DnaA filaments assemble and promote duplex unwinding by engaging and stretching a single DNA strand. While the specificity for duplex DnaA-boxes by DnaA has been appreciated for over 30 years, the sequence specificity for single-strand DNA binding has remained unknown. Here we identify a new indispensable bacterial replication origin element composed of a repeating trinucleotide motif that we term the DnaA-trio. We show that the function of the DnaA-trio is to stabilize DnaA filaments on a single DNA strand, thus providing essential precision to this binding mechanism. Bioinformatic analysis detects DnaA-trios in replication origins throughout the bacterial kingdom, indicating that this element is part of the core oriC structure. The discovery and characterization of the novel DnaA-trio extends our fundamental understanding of bacterial DNA replication initiation, and because of the conserved structure of AAA+ initiator proteins these findings raise the possibility of specific recognition motifs within replication origins of higher organisms.

  18. On certain geodesic conjugacies of flat cylinders

    Indian Academy of Sciences (India)

    called Cr-conjugacy rigid if whenever (M,g) is Cr geodesically conjugate to a complete. Riemannian manifold (N , h), ... to an infinite right circular cylinder in the three dimensional Euclidean space. Moreover, the radius of ... Also, it follows from the geodesic equation that a parallel r = r0 of S is a closed geodesic if and only if.

  19. UF6 cylinder lifting equipment enhancements

    International Nuclear Information System (INIS)

    Hortel, J.M.

    1991-01-01

    This paper presents numerous enhancements that have been made to the Portsmouth lifting equipment to ensure the safe handling of cylinders containing liquid uranium hexafluoride (UF 6 ). The basic approach has been to provide redundancy to all components of the lift path so that any one component failure would not cause the load to drop or cause any undesirable movement. 4 figs

  20. A jumping cylinder in an incline

    Science.gov (United States)

    Gomez, Raul W.; Hernandez, Jorge; Marquina, Vivianne

    2012-02-01

    The problem of a cylinder of mass m and radius r, with its center of mass out of the cylinder axis, rolling in an incline that makes an angle α respect to the horizontal is analyzed. The equation of motion is solved to obtain the site where the cylinder loses contact with the incline (jumps). Several simplifications are made: the analyzed system consists of an homogeneous disc with a one dimensional straight line of mass parallel to the disc axis at a distance d Styrofoam cylinder of radius r = 10.0 ± 0.05 cm, high h = 5.55 ± 0.05 cm and a mass m1 = 24.45 ± 0.05 g, to which a 9.50 ± 0.01 mm diameter and 5.10 ± 0.001 cm long brass road of mass m2 = 30.75 ± 0.05 g was imbibed parallel to the disc axis at a distance of 5.40 ± 0.05 cm from it. Then the disc rolls on a 3.20 m long wooden ramp inclined at 30 and 45 respect to the horizontal. To determine the jumping site, the movements were recorded with a high-speed video camera (Casio EX ZR100) at 400 frames per second. The experimental results agree well with the theoretical predictions.

  1. The Experience Cylinder, an immersive interactive platform

    DEFF Research Database (Denmark)

    Andreasen, Troels; Gallagher, John Patrick; Møbius, Nikolaj

    2011-01-01

    This paper describes the development of an experimental interactive installation, a so-called "experience cylinder", intended as a travelogue and developed specifically to provide a narrative about the Viking ship Sea Stallion’s (Havhingst) voyage from Roskilde to Dublin and back. The installatio...

  2. Cylindrical vortex wake model: right cylinder

    DEFF Research Database (Denmark)

    Branlard, Emmanuel; Gaunaa, Mac

    2015-01-01

    The vortex system consisting of a bound vortex disk, a root vortex and a vortex cylinder as introduced by Joukowski in 1912 is further studied in this paper. This system can be used for simple modeling of rotors (e.g. wind turbines) with infinite number of blades and finite tip-speed ratios. For ...

  3. Over cylinders en eiwit in urine

    NARCIS (Netherlands)

    Meyler, Leopold

    1932-01-01

    Bij de chronische nefritis ziet men heel vaak onder invloed van eiwitarm voedsel, dat de albuminurie teruggaat en dat de cylinders geheel uit de urine verdwijnen. Men mag dit niet aan een verbetering van den toestand toeschrijven, immers de nierfunctie wordt ondertusschen vaak nog slechter. Als

  4. Reshaping the perfect electrical conductor cylinder arbitrarily

    International Nuclear Information System (INIS)

    Chen Huanyang; Zhang Xiaohe; Luo Xudong; Ma Hongru; Chan Cheting

    2008-01-01

    A general method is proposed to design a cylindrical cloak, concentrator and superscatterer with an arbitrary cross section. The method is demonstrated by the design of a perfect electrical conductor (PEC) reshaper which is able to reshape a PEC cylinder arbitrarily by combining the concept of cloak, concentrator and superscatterer together. Numerical simulations are performed to demonstrate its properties.

  5. Breached cylinder incident at the Portsmouth gaseous diffusion plant

    Energy Technology Data Exchange (ETDEWEB)

    Boelens, R.A. [Martin Marietta Energy Systems, Inc., Piketon, OH (United States)

    1991-12-31

    On June 16, 1990, during an inspection of valves on partially depleted product storage cylinders, a 14-ton partially depleted product cylinder was discovered breached. The cylinder had been placed in long-term storage in 1977 on the top row of Portsmouth`s (two rows high) storage area. The breach was observed when an inspector noticed a pile of green material along side of the cylinder. The breach was estimated to be approximately 8- inches wide and 16-inches long, and ran under the first stiffening ring of the cylinder. During the continuing inspection of the storage area, a second 14-ton product cylinder was discovered breached. This cylinder was stacked on the bottom row in the storage area in 1986. This breach was also located adjacent to a stiffening ring. This paper will discuss the contributing factors of the breaching of the cylinders, the immediate response, subsequent actions in support of the investigation, and corrective actions.

  6. Analysis of fatigue life for tube trailer cylinders

    OpenAIRE

    Xinqi YU; Bolong SONG; Zhao ZHANG; Qinggang LIU

    2015-01-01

    Risk of fatigue failure exists in the tube trailer cylinders under the condition of internal pressure variation and inertial load caused through road transport. In order to estimate the safety state of the cylinders under the action of alternating load, the model of certain geometry sizes is built based on the widely used tube trailer cylinders. The fatigue analysis of tube trailer gas cylinders is made aiming at the action of the internal pressure and the inertial load. The fatigue life dist...

  7. Inner and outer cylinders of the CMS vacuum tank.

    CERN Document Server

    Patrice Loïez

    2002-01-01

    The vacuum tank of the CMS magnet system consists of inner and outer stainless-steel cylinders and houses the superconducting coil. The inner cylinder contains all the barrel sub-detectors, which it supports via a system of horizontal rails. The cylinder is pictured here in the vertical position on a yellow platform mounted on the ferris-wheel support structure. This will allow it to be pivoted and inserted into the already installed outer cylinder, through which this photo was taken.

  8. Open revolver cylinder at the suicide death scene.

    Science.gov (United States)

    Wetli, Charles V; Krivosta, George; Sturiano, Jack V

    2002-09-01

    Revolvers with an open cylinder were found at three death scenes of apparently self-inflicted gunshot wounds. All three handguns were Smith & Wesson.38 or.357 revolvers. Investigation revealed that firing the gun with the thumb on the cylinder release latch could disengage the cylinder. A combination of gravity and recoil impact against the thumb would open the cylinder and even allow the casing and the unspent cartridges to fall from the gun, creating a confusing death scene.

  9. Strength Tests of Thin-Walled Duralumin Cylinders in Compression

    Science.gov (United States)

    Lundquist, Eugene E

    1934-01-01

    This report is the second of a series presenting the results of strength tests of thin-walled duralumin cylinders and truncated cones of circular and elliptic section. It contains the results obtained from compression tests on 45 thin-walled duralumin cylinders of circular section with ends clamped to rigid bulkheads. In addition to the tests on duralumin cylinders, there are included the results of numerous tests on rubber, celluloid, steel, and brass cylinders obtained from various sources.

  10. Theoretical and experimental stress analyses of ORNL thin-shell cylinder-to-cylinder model 2

    International Nuclear Information System (INIS)

    Gwaltney, R.C.; Bolt, S.E.; Bryson, J.W.

    1975-10-01

    Model 2 in a series of four thin-shell cylinder-to-cylinder models was tested, and the experimentally determined elastic stress distributions were compared with theoretical predictions obtained from a thin-shell finite-element analysis. Both the cylinder and the nozzle of model 2 had outside diameters of 10 in., giving a d 0 /D 0 ratio of 1.0, and both had outside diameter/thickness ratios of 100. Sixteen separate loading cases in which one end of the cylinder was rigidly held were analyzed. An internal pressure loading, three mutually perpendicular force components, and three mutually perpendicular moment components were individually applied at the free end of the cylinder and at the end of the nozzle. In addition to these 13 loadings, 3 additional loads were applied to the nozzle (in-plane bending moment, out-of-plane bending moment, and axial force) with the free end of the cylinder restrained. The experimental stress distributions for each of the 16 loadings were obtained using 152 three-gage strain rosettes located on the inner and outer surfaces. All the 16 loading cases were also analyzed theoretically using a finite-element shell analysis. The analysis used flat-plate elements and considered five degrees of freedom per node in the final assembled equations. The comparisons between theory and experiment show reasonably good general agreement, and it is felt that the analysis would be satisfactory for most engineering purposes. (auth)

  11. DNA Interaction Studies of Selected Polyamine Conjugates

    Directory of Open Access Journals (Sweden)

    Marta Szumilak

    2016-09-01

    Full Text Available The interaction of polyamine conjugates with DNA double helix has been studied. Binding properties were examined by ethidium bromide (EtBr displacement and DNA unwinding/topoisomerase I/II (Topo I/II activity assays, as well as dsDNA thermal stability studies and circular dichroism spectroscopy. Genotoxicity of the compounds was estimated by a comet assay. It has been shown that only compound 2a can interact with dsDNA via an intercalative binding mode as it displaced EtBr from the dsDNA-dye complex, with Kapp = 4.26 × 106 M−1; caused an increase in melting temperature; changed the circular dichroism spectrum of dsDNA; converted relaxed plasmid DNA into a supercoiled molecule in the presence of Topo I and reduced the amount of short oligonucleotide fragments in the comet tail. Furthermore, preliminary theoretical study has shown that interaction of the discussed compounds with dsDNA depends on molecule linker length and charge distribution over terminal aromatic chromophores.

  12. 30 CFR 57.16005 - Securing gas cylinders.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Securing gas cylinders. 57.16005 Section 57.16005 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL... Storage and Handling § 57.16005 Securing gas cylinders. Compressed and liquid gas cylinders shall be...

  13. 46 CFR 197.338 - Compressed gas cylinders.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Compressed gas cylinders. 197.338 Section 197.338... STANDARDS GENERAL PROVISIONS Commercial Diving Operations Equipment § 197.338 Compressed gas cylinders. Each compressed gas cylinder must— (a) Be stored in a ventilated area; (b) Be protected from excessive heat; (c...

  14. 30 CFR 56.16005 - Securing gas cylinders.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Securing gas cylinders. 56.16005 Section 56.16005 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL... and Handling § 56.16005 Securing gas cylinders. Compressed and liquid gas cylinders shall be secured...

  15. Image analysis of moving seeds in an indented cylinder

    DEFF Research Database (Denmark)

    Buus, Ole; Jørgensen, Johannes Ravn

    2010-01-01

    inspection in seed cleaning equipment. A prototype of an indented cylinder will be constructed. To make it more dynamic, the cylinder itself will be manufactured using 3D printing technology. The input will come either from 3D scans of existing cylinders or by defining their topology using parametric B...

  16. Investigation of breached depleted UF{sub 6} cylinders

    Energy Technology Data Exchange (ETDEWEB)

    DeVan, J.H. [Martin Marietta Energy Systems, Inc., Oak Ridge, TN (United States)

    1991-12-31

    In June 1990, during a three-site inspection of cylinders being used for long-term storage of solid depleted UF{sub 6}, two 14-ton cylinders at Portsmouth, Ohio, were discovered with holes in the barrel section of the cylinders. An investigation team was immediately formed to determine the cause of the failures and their impact on future storage procedures and to recommend corrective actions. Subsequent investigation showed that the failures most probably resulted from mechanical damage that occurred at the time that the cylinders had been placed in the storage yard. In both cylinders evidence pointed to the impact of a lifting lug of an adjacent cylinder near the front stiffening ring, where deflection of the cylinder could occur only by tearing the cylinder. The impacts appear to have punctured the cylinders and thereby set up corrosion processes that greatly extended the openings in the wall and obliterated the original crack. Fortunately, the reaction products formed by this process were relatively protective and prevented any large-scale loss of uranium. The main factors that precipitated the failures were inadequate spacing between cylinders and deviations in the orientations of lifting lugs from their intended horizontal position. After reviewing the causes and effects of the failures, the team`s principal recommendation for remedial action concerned improved cylinder handling and inspection procedures. Design modifications and supplementary mechanical tests were also recommended to improve the cylinder containment integrity during the stacking operation.

  17. Imperfection effects on the buckling of hydrostatically loaded cylinders

    DEFF Research Database (Denmark)

    Pinna, Rodney; Madsen, Søren

    2015-01-01

    imperfection sensitivity. Work on cylinders with other loading conditions, such as hydrostatic loading, is more limited. Similarly, there is limited work on cylinders with boundary conditions other than simply-supported ends. This paper looks at the case of cylinders under hydrostatic load, which is often...

  18. Energy Absorption of Monolithic and Fibre Reinforced Aluminium Cylinders

    NARCIS (Netherlands)

    De Kanter, J.L.C.G.

    2006-01-01

    Summary accompanying the thesis: Energy Absorption of Monolithic and Fibre Reinforced Aluminium Cylinders by Jens de Kanter This thesis presents the investigation of the crush behaviour of both monolithic aluminium cylinders and externally fibre reinforced aluminium cylinders. The research is based

  19. NS3 from Hepatitis C Virus Strain JFH-1 Is an Unusually Robust Helicase That Is Primed To Bind and Unwind Viral RNA

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Ting; Ren, Xiaoming; Adams, Rebecca L.; Pyle, Anna Marie; Ou, J. -H. James

    2017-10-25

    Hepatitis C viruses (HCV) encode a helicase enzyme that is essential for viral replication and assembly (nonstructural protein 3 [NS3]). This helicase has become the focus of extensive basic research on the general helicase mechanism, and it is also of interest as a novel drug target. Despite the importance of this protein, mechanistic work on NS3 has been conducted almost exclusively on variants from HCV genotype 1. Our understanding of NS3 from the highly active HCV strains that are used to study HCV genetics and mechanism in cell culture (such as JFH-1) is lacking. We therefore set out to determine whether NS3 from the replicatively efficient genotype 2a strain JFH-1 displays novel functional or structural properties. Using biochemical assays for RNA binding and duplex unwinding, we show that JFH-1 NS3 binds RNA much more rapidly than the previously studied NS3 variants from genotype 1b. Unlike NS3 variants from other genotypes, JFH-1 NS3 binds RNA with high affinity in a functionally active form that is capable of immediately unwinding RNA duplexes without undergoing rate-limiting conformational changes that precede activation. Unlike other superfamily 2 (SF2) helicases, JFH-1 NS3 does not require long 3' overhangs, and it unwinds duplexes that are flanked by only a few nucleotides, as in the folded HCV genome. To understand the physical basis for this, we solved the crystal structure of JFH-1 NS3, revealing a novel conformation that contains an open, positively charged RNA binding cleft that is primed for productive interaction with RNA targets, potentially explaining robust replication by HCV JFH-1.

    IMPORTANCEGenotypes of HCV are as divergent as different types of flavivirus, and yet mechanistic features of HCV variants are presumed to be held in common. One of the most well-studied components of the HCV replication complex is a helicase known as nonstructural protein 3 (NS3). We set out to determine whether this important

  20. Stabilization of flow past a cylinder with rounded corners

    Science.gov (United States)

    Zhang, Wei; Samtaney, Ravi

    2015-11-01

    We present results of global linear stability analysis for flow past a cylinder in the low Reynolds number regime Re = 50 - 110 . The four corners of the square cylinder are rounded with a radius of curvature R+ = R / D in which R is the rounding radius and D is the cylinder diameter. Analysis is carried out for R+ = 0 . 00 (square cylinder with sharp corners) to R+ = 0 . 50 (circular cylinder) to investigate its effect on the stability characteristics of the flow. The results reveal that the flow may be stabilized by the rounding of the corners for Re Gene/P Shaheen at KAUST was utilized for the simulations.

  1. Upgraded Analytical Model of the Cylinder Test

    Energy Technology Data Exchange (ETDEWEB)

    Souers, P. Clark [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States). Energetic Materials Center; Lauderbach, Lisa [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States). Energetic Materials Center; Garza, Raul [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States). Energetic Materials Center; Ferranti, Louis [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States). Energetic Materials Center; Vitello, Peter [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States). Energetic Materials Center

    2013-03-15

    A Gurney-type equation was previously corrected for wall thinning and angle of tilt, and now we have added shock wave attenuation in the copper wall and air gap energy loss. Extensive calculations were undertaken to calibrate the two new energy loss mechanisms across all explosives. The corrected Gurney equation is recommended for cylinder use over the original 1943 form. The effect of these corrections is to add more energy to the adiabat values from a relative volume of 2 to 7, with low energy explosives having the largest correction. The data was pushed up to a relative volume of about 15 and the JWL parameter ω was obtained directly. Finally, the total detonation energy density was locked to the v = 7 adiabat energy density, so that the Cylinder test gives all necessary values needed to make a JWL.

  2. Upgraded Analytical Model of the Cylinder Test

    Energy Technology Data Exchange (ETDEWEB)

    Souers, P. Clark; Lauderbach, Lisa; Garza, Raul; Ferranti, Louis; Vitello, Peter

    2013-03-15

    A Gurney-type equation was previously corrected for wall thinning and angle of tilt, and now we have added shock wave attenuation in the copper wall and air gap energy loss. Extensive calculations were undertaken to calibrate the two new energy loss mechanisms across all explosives. The corrected Gurney equation is recommended for cylinder use over the original 1943 form. The effect of these corrections is to add more energy to the adiabat values from a relative volume of 2 to 7, with low energy explosives having the largest correction. The data was pushed up to a relative volume of about 15 and the JWL parameter ω was obtained directly. The total detonation energy density was locked to the v=7 adiabat energy density, so that the Cylinder test gives all necessary values needed to make a JWL.

  3. Fluid structural response of axially cracked cylinders

    International Nuclear Information System (INIS)

    Garnich, M.R.; Simoneh, F.A.

    1985-01-01

    The fluid structural (FS) response of a cylindrical pressure vessel to a suddenly occurring longitudinal through-wall crack is predicted. The effects of vessel internals and depressurization of the compressed water on dynamic crack opening displacements are investigated. A three dimensional (3D) structural finite element model is used as a basis for the development of a two dimensional (2D) FS model. A slice of the vessel taken at the crack midspan and normal to the cylinder axis is modeled. Crack opening displacements are compared between the 2D and 3D models, between the different assumptions about fluid depressurization, and between the static and dynamic solutions. The results show that effects of dynamic amplification associated with the sudden opening of the crack in the cylinder are largely offset by the local depressurization of the fluid adjacent to the crack

  4. BLM–DNA2–RPA–MRN and EXO1–BLM–RPA–MRN constitute two DNA end resection machineries for human DNA break repair

    Science.gov (United States)

    Nimonkar, Amitabh V.; Genschel, Jochen; Kinoshita, Eri; Polaczek, Piotr; Campbell, Judith L.; Wyman, Claire; Modrich, Paul; Kowalczykowski, Stephen C.

    2011-01-01

    Repair of dsDNA breaks requires processing to produce 3′-terminated ssDNA. We biochemically reconstituted DNA end resection using purified human proteins: Bloom helicase (BLM); DNA2 helicase/nuclease; Exonuclease 1 (EXO1); the complex comprising MRE11, RAD50, and NBS1 (MRN); and Replication protein A (RPA). Resection occurs via two routes. In one, BLM and DNA2 physically and specifically interact to resect DNA in a process that is ATP-dependent and requires BLM helicase and DNA2 nuclease functions. RPA is essential for both DNA unwinding by BLM and enforcing 5′ → 3′ resection polarity by DNA2. MRN accelerates processing by recruiting BLM to the end. In the other, EXO1 resects the DNA and is stimulated by BLM, MRN, and RPA. BLM increases the affinity of EXO1 for ends, and MRN recruits and enhances the processivity of EXO1. Our results establish two of the core machineries that initiate recombinational DNA repair in human cells. PMID:21325134

  5. Analysis of fatigue life for tube trailer cylinders

    Directory of Open Access Journals (Sweden)

    Xinqi YU

    2015-08-01

    Full Text Available Risk of fatigue failure exists in the tube trailer cylinders under the condition of internal pressure variation and inertial load caused through road transport. In order to estimate the safety state of the cylinders under the action of alternating load, the model of certain geometry sizes is built based on the widely used tube trailer cylinders. The fatigue analysis of tube trailer gas cylinders is made aiming at the action of the internal pressure and the inertial load. The fatigue life distribution of cylinders is obtained under the condition of different loads through the numerical simulation by ANSYS Workbench. The analysis results show that under internal pressure, gas cylinders have limited fatigue life, but can satisfy the requirements; when the inertial load exceeds a certain value, natural gas cylinders of tube trailer is under finite life state, which does not meet the requirements of strength, therefore the inertial load should be controlled.

  6. Radiation levels on empty cylinders containing heel material

    Energy Technology Data Exchange (ETDEWEB)

    Shockley, C.W. [Martin Marietta Energy Systems, Inc., Paducah, KY (United States)

    1991-12-31

    Empty UF{sub 6} cylinders containing heel material were found to emit radiation levels in excess of 200 mr/hr, the maximum amount stated in ORO-651. The radiation levels were as high as 335 mr/hr for thick wall (48X and 48Y) cylinders and 1050 mr/hr for thin wall (48G and 48H) cylinders. The high readings were found only on the bottom of the cylinders. These radiation levels exceeded the maximum levels established in DOT 49 CFR, Part 173.441 for shipment of cylinders. Holding periods of four weeks for thick-wall cylinders and ten weeks for thin-wall cylinders were established to allow the radiation levels to decay prior to shipment.

  7. Carbon fiber reinforced hierarchical orthogrid stiffened cylinder: Fabrication and testing

    Science.gov (United States)

    Wu, Hao; Lai, Changlian; Sun, Fangfang; Li, Ming; Ji, Bin; Wei, Weiyi; Liu, Debo; Zhang, Xi; Fan, Hualin

    2018-04-01

    To get strong, stiff and light cylindrical shell, carbon fiber reinforced hierarchical orthogrid stiffened cylinders are designed and fabricated. The cylinder is stiffened by two-scale orthogrid. The primary orthogrid has thick and high ribs and contains several sub-orthogrid cells whose rib is much thinner and lower. The primary orthogrid stiffens the bending rigidity of the cylinder to resist the global instability while the sub-orthogrid stiffens the bending rigidity of the skin enclosed by the primary orthogrid to resist local buckling. The cylinder is fabricated by filament winding method based on a silicone rubber mandrel with hierarchical grooves. Axial compression tests are performed to reveal the failure modes. With hierarchical stiffeners, the cylinder fails at skin fracture and has high specific strength. The cylinder will fail at end crushing if the end of the cylinder is not thickened. Global instability and local buckling are well restricted by the hierarchical stiffeners.

  8. Mechanical Cushion Design Influence on Cylinder Dynamics

    DEFF Research Database (Denmark)

    Borghi, Massimo; Milani, Massimo; Conrad, Finn

    2005-01-01

    The paper deals with the simulation and the experimental verification of the dynamic behaviour of a linear actuator equipped with different configurations of mechanical cushion. A numerical model, developed and tailored to describe the influence of different modulation of the discharged flow....... experimental comparison, involving the piston velocity and the cylinder chambers pressure. After, with the aim of highlighting the effect of mechanical cushions design on a two effect linear actuator dynamic performances, the characteristics modulation of four alternative cushioning systems are determined...

  9. Combined convective heat transfer from short cylinders

    International Nuclear Information System (INIS)

    Oosthuizen, P.H.; Paul, J.T.

    1985-01-01

    Considerable experimental evidence has been produced recently showing that the free convective heat transfer rate from horizontal circular cylinders becomes influenced by the length to diameter ratio L/D. The major aim of the present study was to determine the influence of the L/D ratio on the conditions under which buoyancy forces cause the heat transfer rate to start to deviate significantly from that existing in purely forced convection

  10. Chaotic Rotation of a Towed Elliptical Cylinder

    OpenAIRE

    Weymouth, G D

    2013-01-01

    In this paper I consider the self-excited rotation of an elliptical cylinder towed in a viscous fluid as a canonical model of nonlinear fluid structure interactions with possible applications in the design of sensors and energy extraction devices. First, the self-excited ellipse system is shown to be analogous to the forced bistable oscillators studied in classic chaos theory. A single variable, the distance between the pivot and the centroid, governs the system bifurcation into bi-stability....

  11. Genotoxicity of cadmium chloride in the marine gastropod Nerita chamaeleon using comet assay and alkaline unwinding assay

    Digital Repository Service at National Institute of Oceanography (India)

    Sarkar, A.; Bhagat, J.; Ingole, B.S.; Rao, P.V.S.S.D.P.; Markad, V.L.

    in control. Exposure to 75 mu g/L of CdCl2 produced significant decrease in DNA integrity as measured by DAUA at all duration with respect to control. In vivo exposure to different concentrations of CdCl2 (10, 25, 50, and 75 mu g/L) to N...

  12. Repair of radiation-induced DNA damage in rat epidermis as a function of age

    International Nuclear Information System (INIS)

    Sargent, E.V.; Burns, F.J.

    1985-01-01

    The rate of repair of radiation-induced DNA damage in proliferating rat epidermal cells diminished progressively with increasing age of the animal. The dorsal skin was irradiated with 1200 rad of 0.8 MeV electrons at various ages, and the amount of DNA damage was determined as a function of time after irradiation by the method of alkaline unwinding followed by S 1 nuclease digestion. The amount of DNA damage immediately after irradiation was not age dependent, while the rate of damage removal from the DNA decreased with increasing age. By fitting an exponential function to the relative amount of undamaged DNA as a function of time after irradiation, DNA repair halftimes of 20, 27, 69, and 107 min were obtained for 28, 100-, 200-, and 400-day-old animals, respectively

  13. Theoretical and experimental stress analyses of ORNL thin-shell cylinder-to-cylinder model 3

    International Nuclear Information System (INIS)

    Gwaltney, R.C.; Bolt, S.E.; Corum, J.M.; Bryson, J.W.

    1975-06-01

    The third in a series of four thin-shell cylinder-to-cylinder models was tested, and the experimentally determined elastic stress distributions were compared with theoretical predictions obtained from a thin-shell finite-element analysis. The models are idealized thin-shell structures consisting of two circular cylindrical shells that intersect at right angles. There are no transitions, reinforcements, or fillets in the junction region. This series of model tests serves two basic purposes: the experimental data provide design information directly applicable to nozzles in cylindrical vessels; and the idealized models provide test results for use in developing and evaluating theoretical analyses applicable to nozzles in cylindrical vessels and to thin piping tees. The cylinder of model 3 had a 10 in. OD and the nozzle had a 1.29 in. OD, giving a d 0 /D 0 ratio of 0.129. The OD/thickness ratios for the cylinder and the nozzle were 50 and 7.68 respectively. Thirteen separate loading cases were analyzed. In each, one end of the cylinder was rigidly held. In addition to an internal pressure loading, three mutually perpendicular force components and three mutually perpendicular moment components were individually applied at the free end of the cylinder and at the end of the nozzle. The experimental stress distributions for all the loadings were obtained using 158 three-gage strain rosettes located on the inner and outer surfaces. The loading cases were also analyzed theoretically using a finite-element shell analysis developed at the University of California, Berkeley. The analysis used flat-plate elements and considered five degrees of freedom per node in the final assembled equations. The comparisons between theory and experiment show reasonably good agreement for this model. (U.S.)

  14. Theoretical and experimental stress analyses of ORNL thin-shell cylinder-to-cylinder model 4

    International Nuclear Information System (INIS)

    Gwaltney, R.C.; Bolt, S.E.; Bryson, J.W.

    1975-06-01

    The last in a series of four thin-shell cylinder-to-cylinder models was tested, and the experimentally determined elastic stress distributions were compared with theoretical predictions obtained from a thin-shell finite-element analysis. The models in the series are idealized thin-shell structures consisting of two circular cylindrical shells that intersect at right angles. There are no transitions, reinforcements, or fillets in the junction region. This series of model tests serves two basic purposes: (1) the experimental data provide design information directly applicable to nozzles in cylindrical vessels, and (2) the idealized models provide test results for use in developing and evaluating theoretical analyses applicable to nozzles in cylindrical vessels and to thin piping tees. The cylinder of model 4 had an outside diameter of 10 in., and the nozzle had an outside diameter of 1.29 in., giving a d 0 /D 0 ratio of 0.129. The OD/thickness ratios were 50 and 20.2 for the cylinder and nozzle respectively. Thirteen separate loading cases were analyzed. For each loading condition one end of the cylinder was rigidly held. In addition to an internal pressure loading, three mutually perpendicular force components and three mutually perpendicular moment components were individually applied at the free end of the cylinder and at the end of the nozzle. The experimental stress distributions for each of the 13 loadings were obtained using 157 three-gage strain rosettes located on the inner and outer surfaces. Each of the 13 loading cases was also analyzed theoretically using a finite-element shell analysis developed at the University of California, Berkeley. The analysis used flat-plate elements and considered five degrees of freedom per node in the final assembled equations. The comparisons between theory and experiment show reasonably good agreement for this model. (U.S.)

  15. Measurements of the Flowfield Interaction Between Tandem Cylinders

    Science.gov (United States)

    Neuhart, Dan H.; Jenkins, Luther N.; Choudhari, Meelan M.; Khorrami, Mehdi R.

    2009-01-01

    This paper presents the most recent measurements from an ongoing investigation of the unsteady wake interference between a pair of circular cylinders in tandem. The purpose of this investigation is to help build an in-depth experimental database for this canonical flow configuration that embodies the effects of component interaction in landing gear noise. This new set of measurements augments the previous database at the primary Reynolds number (based on tunnel speed and cylinder diameter) of 1.66 105 in four important respects. First, better circumferential resolution of surface pressure fluctuations is obtained via cylinder "clocking". Second, higher resolution particle image velocimetry measurements of the shear layer separating from the cylinders are achieved. Third, the effects of simultaneous boundary layer trips along both the front and rear cylinders, versus front cylinder alone in the previous measurements, are studied. Lastly, on-surface and off-surface characteristics of unsteady flow near the "critical" cylinder spacing, wherein the flow switches intermittently between two states that are characteristic of lower and higher spacings, are examined. This critical spacing occurs in the middle of a relatively sudden change in the drag of either cylinder and is characterized by a loud intermittent noise and a flow behavior that randomly transitions between shear layer attachment to the rear cylinder and constant shedding and rollup in front of it. Analysis of this bistable flow state reveals much larger spanwise correlation lengths of surface pressure fluctuations than those at larger and smaller values of the cylinder spacing.

  16. Differences in scour around a single surface-piercing cylinder and a submerged cylinder

    Science.gov (United States)

    Beninati, M. L.; Volpe, M. A.; Riley, D. R.; Krane, M.

    2011-12-01

    The equilibrium state of scour for a single surface piercing cylinder and a submerged cylinder of specific aspect ratio are presented. The equilibrium state is defined by a scour depth and associated time interval for a given set of flow conditions. Control variables such as sediment coarseness (or grain size) and cylinder size are held constant, while the flow intensity is varied. Sediment bed form topology is characterized with a series of two-dimensional slices across the bed for both the surface-piercing and submerged cylinder cases. Test results will help identify the geometry and pattern of the scour around the cylinders to aid in the optimal design of marine hydrokinetic (MHK) support structures in an effort to help minimize the deleterious impact of these devices on the local substrate. This study is performed in the small-scale testing platform in the hydraulic flume facility (32 ft long, 4 ft wide and 1.25 ft deep) in the Environmental Fluid Mechanics and Hydraulics Laboratory (EFM&H) at Bucknell University. The cylinders, of the same material and diameter, are placed centrally in the sediment filled test section (2.5 ft long, 2 ft wide and 0.75 ft deep) of the platform. Flow field measurements are taken with a 16-MHz Micro Acoustic Doppler Velocimeter while water depth is acquired using an ultrasonic distance sensor. These devices are attached to a gantry system that can be accurately positioned anywhere in the test section. Clear-water conditions (in the absence of live-bed scour) are maintained to study the effect of the horseshoe and wake vortices on the displacement of sediment around the cylinder as well as downstream of the device. Bed form topology is measured using an HR Wallingford 2D Sediment Bed Profiler with a low-powered laser distance sensor to accurately characterize changes in bed form around the cylinders. Additionally, specifications for testing such as operational procedures for start-up and shut-down of the facility are given.

  17. Electrochemical DNA probe for Hg(2+) detection based on a triple-helix DNA and Multistage Signal Amplification Strategy.

    Science.gov (United States)

    Wang, Huan; Zhang, Yihe; Ma, Hongmin; Ren, Xiang; Wang, Yaoguang; Zhang, Yong; Wei, Qin

    2016-12-15

    In this work, an ultrasensitive electrochemical sensor was developed for detection of Hg(2+). Gold nanoparticles decorated bovine serum albumin reduction of graphene oxide (AuNP-BSA-rGO) were used as subsurface material for the immobilization of triple-helix DNA. The triple-helix DNA containing a thiol labelled single-stranded DNA (sDNA) and a thymine-rich DNA (T-rich DNA), which could be unwinded in the present of Hg(2+) to form more stable thymine-Hg(2+)-thymine (T-Hg(2+)-T) complex. T-Hg(2+)-T complex was then removed and the sDNA was left on the electrode. At this time, gold nanoparticle carrying thiol labelled cytosine-rich complementary DNA (cDNA-AuNP) could bind with the free sDNA. Meanwhile, the other free cDNA on AuNP could bind with each other in the present of Ag(+) to form the stable cytosine-Ag(+)-cytosine (C-Ag(+)-C) complex and circle amplification. Plenty of C-Ag(+)-C could form silver nanoclusters by electrochemical reduction and the striping signal of Ag could be measured for purpose of the final electrochemical detection of Hg(2+). This sensor could detect Hg(2+) over a wide concentration range from 0.1 to 130nM with a detection limit of 0.03nM. Copyright © 2016 Elsevier B.V. All rights reserved.

  18. Adaptronic tools for superfinishing of cylinder bores

    Science.gov (United States)

    Roscher, Hans-Jürgen; Hochmuth, Carsten; Hoffmann, Michael; Praedicow, Michael

    2012-04-01

    Today in the production of internal combustion engines it is possible to make pistons as well as cylinders, for all practical purposes, perfectly round. The negative consequences of the subsequent assembly processes and operation of the engine is that the cylinders and pistons are deformed, resulting in a loss of power and an increase in fuel consumption. This problem can be solved by using an adaptronic tool, which can machine the cylinder to a predetermined nonround geometry, which will deform to the required geometry during assembly and operation of the engine. The article describes the actuatory effect of the tool in conjunction with its measuring and controlling algorithms. The adaptronic tool consists out the basic tool body and three axially-staggered floating cutter groups, these cutter groups consist out of guides, actuators and honing stones. The selective expansion of the tool is realised by 3 piezoelectric multilayer-actuators deployed in a series - parallel arrangement. It is also possible to superimpose actuator expansion on the conventional expansion. A process matrix is created during the processing of the required and actual contour data in a technology module. This is then transferred over an interface to the machine controller where it is finally processed and the setting values for the piezoelectric actuators are derived, after which an amplifier generates the appropriate actuator voltages. A slip ring system on the driveshaft is used to transfer the electricity to the actuators in the machining head. The functioning of the adaptronic form-honing tool and process were demonstrated with numerous experiments. The tool provides the required degrees of freedom to generate a contour that correspond to the inverse compound contour of assembled and operational engines.

  19. Active aerodynamic drag reduction on morphable cylinders

    Science.gov (United States)

    Guttag, M.; Reis, P. M.

    2017-12-01

    We study a mechanism for active aerodynamic drag reduction on morphable grooved cylinders, whose topography can be modified pneumatically. Our design is inspired by the morphology of the Saguaro cactus (Carnegiea gigantea), which possesses an array of axial grooves, thought to help reduce aerodynamic drag, thereby enhancing the structural robustness of the plant under wind loading. Our analog experimental samples comprise a spoked rigid skeleton with axial cavities, covered by a stretched elastomeric film. Decreasing the inner pressure of the sample produces axial grooves, whose depth can be accurately varied, on demand. First, we characterize the relation between groove depth and pneumatic loading through a combination of precision mechanical experiments and finite element simulations. Second, wind tunnel tests are used to measure the aerodynamic drag coefficient (as a function of Reynolds number) of the grooved samples, with different levels of periodicity and groove depths. We focus specifically on the drag crisis and systematically measure the associated minimum drag coefficient and the critical Reynolds number at which it occurs. The results are in agreement with the classic literature of rough cylinders, albeit with an unprecedented level of precision and resolution in varying topography using a single sample. Finally, we leverage the morphable nature of our system to dynamically reduce drag for varying aerodynamic loading conditions. We demonstrate that actively controlling the groove depth yields a drag coefficient that decreases monotonically with Reynolds number and is significantly lower than the fixed sample counterparts. These findings open the possibility for the drag reduction of grooved cylinders to be operated over a wide range of flow conditions.

  20. Effect of Surface Coatings on Cylinders Exposed to Underwater Shock

    Directory of Open Access Journals (Sweden)

    Y.W. Kwon

    1994-01-01

    Full Text Available The response of a coated cylinder (metallic cylinder coated with a rubber material subjected to an underwater explosion is analyzed numerically. The dynamic response of the coated cylinder appears to be adversely affected when impacted by an underwater shock wave under certain conditions of geometry and material properties of the coating. When adversely affected, significant deviations in values of axial stress, hoop stress, and strain are observed. The coated cylinder exhibits a larger deformation and higher internal energy in the metallic material. Rubber coatings appeared to inhibit energy dissipation from the metallic material to the surrounding water medium. A parametric study of various coatings was performed on both aluminum and steel cylinders. The adverse effect of the coating decreased when the stiffness of the rubber layer increased, indicating the existence of a threshold value. The results of this study indicate that the stiffness of the coating is a critical factor to the shock hardening of the coated cylinder.

  1. Numerical Study of Shock-Cylinder Banks Interactions

    International Nuclear Information System (INIS)

    Wang, S.P.; Anderson, M.H.; Oakley, J.G.; Bonazza, R.

    2003-01-01

    A numerical parametric study of shock-cylinder banks interactions is presented using a high resolution Euler solver. Staggered cylinder banks of five rows are chosen with the purpose of modeling IFE reactor cooling tube banks. The effect of the aspect ratio of the intercylinder pitch to the distance between successive cylinder rows on the vertical pressure forces acting on the cylinders with different geometries is investigated. Preliminary results show that the largest vertical force develops on the cylinders of the second or third row. This peak pressure force increases with decreasing values of the aspect ratio. It is shown that an increasing second force peak also appears on the successive rows, starting with the second one, with decreasing aspect ratio. It is also observed that the force on the last-row cylinders basically decreases to the level of that on the first row. The results are useful for the optimal design of the cooling tubes system of IFE reactors

  2. Acoustics and Surface Pressure Measurements from Tandem Cylinder Configurations

    Science.gov (United States)

    Hutcheson, Florence V.; Brooks, Thomas F.; Lockard, David P.; Choudhari, Meelan M.; Stead, Daniel J.

    2014-01-01

    Acoustic and unsteady surface pressure measurements from two cylinders in tandem configurations were acquired to study the effect of spacing, surface trip and freestream velocity on the radiated noise. The Reynolds number ranged from 1.15x10(exp 5) to 2.17x10(exp 5), and the cylinder spacing varied between 1.435 and 3.7 cylinder diameters. The acoustic and surface pressure spectral characteristics associated with the different flow regimes produced by the cylinders' wake interference were identified. The dependence of the Strouhal number, peak Sound Pressure Level and spanwise coherence on cylinder spacing and flow velocity was examined. Directivity measurements were performed to determine how well the dipole assumption for the radiation of vortex shedding noise holds for the largest and smallest cylinder spacing tested.

  3. Mounting with compliant cylinders for deformable mirrors.

    Science.gov (United States)

    Reinlein, Claudia; Goy, Matthias; Lange, Nicolas; Appelfelder, Michael

    2015-04-01

    A method is presented to mount large aperture unimorph deformable mirrors by compliant cylinders (CC). The CCs are manufactured from a soft silicone, and shear testing is performed in order to evaluate the Young's modulus. A scale mirror model is assembled to evaluate mount-induced change of piezoelectric deformation, and its applicability for tightly focusing mirrors. Experiments do not show any decrease of piezoelectric stroke. Further it is shown that the changes of surface fidelity by the attachment of the deformable mirror to its mount are neglectable.

  4. Scattering by closely spaced infinite cylinders in an absorbing medium

    Directory of Open Access Journals (Sweden)

    S.-C. Lee

    2011-09-01

    Full Text Available Scattering by closely spaced parallel infinite cylinders in an absorbing medium is considered in this paper. The source wave is arbitrarily polarized and propagates in a general direction at the cylinders. The formulation utilizes the Hertz potential approach, and the scattering cross section and intensity distribution in the far-field are developed. Numerical results are presented to illustrate the influence of the absorbing medium on the scattering properties of two configurations of closely-spaced cylinders.

  5. Electromagnetic forces on type-II superconducting rotating cylinders

    International Nuclear Information System (INIS)

    Saif, A.G.; Refai, T.F.; El-Sabagh, M.A.

    1995-01-01

    Analytical solutions of the electromagnetic fields are presented for a system composed of an infinitely long superconducting cylinder rotating about its axis and placed parallel to two infinitely long normal conducting wires. Both wires carry the same alternating current. From the obtained electromagnetic fields the electromagnetic power loss on the cylinder surface, electromagnetic forces due to induced currents, electromagnetic torque, and the work opposing the rotation of the cylinder are calculated. (orig.)

  6. A model of filament-wound thin cylinders

    Science.gov (United States)

    Calius, Emilio P.; Springer, George S.

    1990-01-01

    A model was developed for simulating he manufacturing process of filament-wound cylinders made of a thermoset matrix composite. The model relates the process variables (winding speed, fiber tension, applied temperature) to the parameters characterizing the composite cylinder and the mandrel. The model is applicable to cylinders for which the diameter is large compared to the wall thickness. The model was implemented by a user-friendly computer code suitable for generating numerical results.

  7. PIV Measurements of He II Counterflow Around a Cylinder

    International Nuclear Information System (INIS)

    Fuzier, S.; Van Stiver, S. W.; Zhang, T.

    2006-01-01

    The induced flow field of counterflow He II across a circular cylinder has been quantitatively studied using the particle image velocimetry (PIV) technique. Two different size cylinders (6.35 mm and 2 mm in diameter) were used and placed in a 20 mm wide rectangular channel. In these experiments, large-scale eddy motion generated by the He II counterflow was observed both in front of and behind the cylinder, an effect which has no analogue in classical fluids

  8. Medical Gas Cylinder with Mismatched Colour and Pin Index

    Directory of Open Access Journals (Sweden)

    Mukherjee S

    2014-08-01

    Full Text Available The medical gas cylinders have various safety features to prevent the administration of wrong gas to the patient. Most of the features have visual impact (colour, label, markings on the cylinder body except pin index system on the cylinder valve, so error in this feature is difficult to analyze and is highly unpredictable. We had received one such cylinder in our institution where all other features (label, colour, marking pointed to nitrous oxide except the pin index which resembled with that of oxygen

  9. An update on corrosion monitoring in cylinder storage yards

    Energy Technology Data Exchange (ETDEWEB)

    Henson, H.M.; Newman, V.S.; Frazier, J.L. [Oak Ridge K-25 Site, TN (United States)

    1991-12-31

    Depleted uranium, from US uranium isotope enrichment activities, is stored in the form of solid uranium hexafluoride (UF{sub 6}) in A285 and A516 steel cylinders designed and manufactured to ASME Boiler and Pressure Vessel Code criteria. In general, storage facilities are open areas adjacent to the enrichment plants where the cylinders are exposed to weather. This paper describes the Oak Ridge program to determine the general corrosion behavior of UF{sub 6} cylinders, to determine cylinder yard conditions which are likely to affect long term storage of this material, and to assess cylinder storage yards against these criteria. This program is targeted at conditions specific to the Oak Ridge cylinder yards. Based on (a) determination of the current cylinder yard conditions, (b) determination of rusting behavior in regions of the cylinders showing accelerated attack, (c) monitoring of corrosion rates through periodic measurement of test coupons placed within the cylinder yards, and (d) establishment of a computer base to incorporate and retain these data, the technical division is working with the enrichment sites to implement an upgraded system for storage of this material until such time as it is used or converted.

  10. Self-accelerating parabolic cylinder waves in 1-D

    Energy Technology Data Exchange (ETDEWEB)

    Yuce, C., E-mail: cyuce@anadolu.edu.tr

    2016-11-25

    Highlights: • We find a new class of self-accelerating waves. • We show that parabolic cylinder waves self-accelerates in a parabolic potential. • We discuss that truncated parabolic cylinder waves propagates large distance without almost being non-diffracted in free space. - Abstract: We introduce a new self-accelerating wave packet solution of the Schrodinger equation in one dimension. We obtain an exact analytical parabolic cylinder wave for the inverted harmonic potential. We show that truncated parabolic cylinder waves exhibits their accelerating feature.

  11. Enrichment Assay Methods Development for the Integrated Cylinder Verification System

    Energy Technology Data Exchange (ETDEWEB)

    Smith, Leon E.; Misner, Alex C.; Hatchell, Brian K.; Curtis, Michael M.

    2009-10-22

    International Atomic Energy Agency (IAEA) inspectors currently perform periodic inspections at uranium enrichment plants to verify UF6 cylinder enrichment declarations. Measurements are typically performed with handheld high-resolution sensors on a sampling of cylinders taken to be representative of the facility's entire product-cylinder inventory. Pacific Northwest National Laboratory (PNNL) is developing a concept to automate the verification of enrichment plant cylinders to enable 100 percent product-cylinder verification and potentially, mass-balance calculations on the facility as a whole (by also measuring feed and tails cylinders). The Integrated Cylinder Verification System (ICVS) could be located at key measurement points to positively identify each cylinder, measure its mass and enrichment, store the collected data in a secure database, and maintain continuity of knowledge on measured cylinders until IAEA inspector arrival. The three main objectives of this FY09 project are summarized here and described in more detail in the report: (1) Develop a preliminary design for a prototype NDA system, (2) Refine PNNL's MCNP models of the NDA system, and (3) Procure and test key pulse-processing components. Progress against these tasks to date, and next steps, are discussed.

  12. Flow past two tandem square cylinders vibrating transversely in phase

    International Nuclear Information System (INIS)

    Mithun, M G; Tiwari, Shaligram

    2014-01-01

    Numerical investigations have been carried out to study the wake characteristics of flow past two tandem square cylinders vibrating in phase. Both the cylinders vibrate in a transverse direction, i.e., perpendicular to the incoming flow with the same frequency and amplitude. The frequency of vibration of the cylinders and the inter-cylinder spacing are varied for fixed values of the Reynolds number (Re = 100) and the amplitude ratio (A/D = 0.4). The synchronous or lock-in regime for the oscillatory wake of the vibrating cylinders has been identified by varying the frequency of the vibration from f e  = 0.4 f 0 to 1.6 f 0 (f 0 being the frequency of vortex shedding behind a stationary square cylinder). The characteristics of lift and drag and the mechanism of vortex shedding are studied by varying the excitation frequency within the lock-in range for each value of inter-cylinder spacing. The complex interaction of flow between the cylinders gives rise to a variety of characteristically different shedding patterns in their wake. For values of inter-cylinder spacing equal to 2D and 3D, periodic, as well as quasi-periodic, lock-in behaviors are observed in the synchronous range. (paper)

  13. Prediction of External Corrosion for Steel Cylinders--2007 Report

    Energy Technology Data Exchange (ETDEWEB)

    Schmoyer, Richard L [ORNL

    2008-01-01

    Depleted uranium hexafluoride (DUF{sub 6}) is stored in over 62,000 containment cylinders at the Paducah Gaseous Diffusion Plant (PGDP) in Paducah, Kentucky, and at the Portsmouth Gaseous Diffusion Plant (PORTS) in Portsmouth, Ohio. Over 4,800 of the cylinders at Portsmouth were recently moved there from the East Tennessee Technology Park (ETTP) in Oak Ridge, Tennessee. The cylinders range in age up to 56 years and come in various models, but most are 48-inch diameter 'thin-wall'(312.5 mil) and 'thick-wall' (625 mil) cylinders and 30-inch diameter '30A' (including '30B') cylinders with 1/2-inch (500 mil) walls. Most of the cylinders are carbon steel, and they are subject to corrosion. The United States Department of Energy (DOE) manages the cylinders to maintain them and the DUF{sub 6} they contain. Cylinder management requirements are specified in the System Requirements Document (LMES 1997a), and the activities to fulfill them are specified in the System Engineering Management Plan (LMES 1997b). This report documents activities that address DUF{sub 6} cylinder management requirements involving measuring and forecasting cylinder wall thicknesses. As part of these activities, ultrasonic thickness (UT) measurements are made on samples of cylinders. For each sampled cylinder, multiple measurements are made in an attempt to find, approximately, the minimum wall thickness. Some cylinders have a skirt, which is an extension of the cylinder wall to protect the head (end) and valve. The head/skirt interface crevice is thought to be particularly vulnerable to corrosion, and for some skirted cylinders, in addition to the main body UT measurements, a separate suite of measurements is also made at the head/skirt interface. The main-body and head/skirt minimum thickness data are used to fit models relating minimum thickness to cylinder age, nominal thicknesses, and cylinder functional groups defined in terms of plant site, storage yard

  14. Terminal project heat convection in thin cylinders

    International Nuclear Information System (INIS)

    Morales Corona, J.

    1992-01-01

    Heat convection in thin cylinders and analysis about natural convection for straight vertical plates, and straight vertical cylinders submersed in a fluid are presented some works carry out by different authors in the field of heat transfer. In the part of conduction, deduction of the equation of heat conduction in cylindrical coordinates by means of energy balance in a control volume is presented. Enthalpy and internal energy are used for the outlining of the equation and finally the equation in its vectorial form is obtained. In the convection part development to calculate the Nusselt number for a straight vertical plate by a forces analysis, an energy balance and mass conservation over a control volume is outlined. Several empiric correlations to calculate the Nusselt number and its relations with other dimensionless numbers are presented. In the experimental part the way in which a prototype rode is assembled is presented measurements of temperatures attained in steady state and in free convection for working fluids as air and water are showed in tables. Also graphs of Nusselt numbers obtained in the experimental way through some empiric correlations are showed (Author)

  15. The capillary interaction between two vertical cylinders

    KAUST Repository

    Cooray, Himantha

    2012-06-27

    Particles floating at the surface of a liquid generally deform the liquid surface. Minimizing the energetic cost of these deformations results in an inter-particle force which is usually attractive and causes floating particles to aggregate and form surface clusters. Here we present a numerical method for determining the three-dimensional meniscus around a pair of vertical circular cylinders. This involves the numerical solution of the fully nonlinear Laplace-Young equation using a mesh-free finite difference method. Inter-particle force-separation curves for pairs of vertical cylinders are then calculated for different radii and contact angles. These results are compared with previously published asymptotic and experimental results. For large inter-particle separations and conditions such that the meniscus slope remains small everywhere, good agreement is found between all three approaches (numerical, asymptotic and experimental). This is as expected since the asymptotic results were derived using the linearized Laplace-Young equation. For steeper menisci and smaller inter-particle separations, however, the numerical simulation resolves discrepancies between existing asymptotic and experimental results, demonstrating that this discrepancy was due to the nonlinearity of the Laplace-Young equation. © 2012 IOP Publishing Ltd.

  16. Mycobacterium tuberculosis UvrB Is a Robust DNA-Stimulated ATPase That Also Possesses Structure-Specific ATP-Dependent DNA Helicase Activity.

    Science.gov (United States)

    Thakur, Manoj; Kumar, Mohan B J; Muniyappa, K

    2016-10-18

    Much is known about the Escherichia coli nucleotide excision repair (NER) pathway; however, very little is understood about the proteins involved and the molecular mechanism of NER in mycobacteria. In this study, we show that Mycobacterium tuberculosis UvrB (MtUvrB), which exists in solution as a monomer, binds to DNA in a structure-dependent manner. A systematic examination of MtUvrB substrate specificity reveals that it associates preferentially with single-stranded DNA, duplexes with 3' or 5' overhangs, and linear duplex DNA with splayed arms. Whereas E. coli UvrB (EcUvrB) binds weakly to undamaged DNA and has no ATPase activity, MtUvrB possesses intrinsic ATPase activity that is greatly stimulated by both single- and double-stranded DNA. Strikingly, we found that MtUvrB, but not EcUvrB, possesses the DNA unwinding activity characteristic of an ATP-dependent DNA helicase. The helicase activity of MtUvrB proceeds in the 3' to 5' direction and is strongly modulated by a nontranslocating 5' single-stranded tail, indicating that in addition to the translocating strand it also interacts with the 5' end of the substrate. The fraction of DNA unwound by MtUvrB decreases significantly as the length of the duplex increases: it fails to unwind duplexes longer than 70 bp. These results, on one hand, reveal significant mechanistic differences between MtUvrB and EcUvrB and, on the other, support an alternative role for UvrB in the processing of key DNA replication intermediates. Altogether, our findings provide insights into the catalytic functions of UvrB and lay the foundation for further understanding of the NER pathway in M. tuberculosis.

  17. 77 FR 26738 - High Pressure Steel Cylinders From the People's Republic of China: Final Affirmative...

    Science.gov (United States)

    2012-05-07

    ... liquefied gas (``high pressure steel cylinders''). High pressure steel cylinders are fabricated of chrome... Cylinders From the People's Republic of China: Final Affirmative Countervailing Duty Determination AGENCY... producers and exporters of high pressure steel cylinders (steel cylinders) from the People's Republic of...

  18. 49 CFR 173.303 - Charging of cylinders with compressed gas in solution (acetylene).

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Charging of cylinders with compressed gas in....303 Charging of cylinders with compressed gas in solution (acetylene). (a) Cylinder, filler and... specification cylinders, the pressure in the cylinder containing acetylene gas may not exceed 250 psig at 70 °F...

  19. DNA replication origins in archaea

    Directory of Open Access Journals (Sweden)

    Zhenfang eWu

    2014-04-01

    Full Text Available DNA replication initiation, which starts at specific chromosomal site (known as replication origins, is the key regulatory stage of chromosome replication. Archaea, the third domain of life, use a single or multiple origin(s to initiate replication of their circular chromosomes. The basic structure of replication origins is conserved among archaea, typically including an AT-rich unwinding region flanked by several conserved repeats (origin recognition box, ORB that are located adjacent to a replication initiator gene. Both the ORB sequence and the adjacent initiator gene are considerably diverse among different replication origins, while in silico and genetic analyses have indicated the specificity between the initiator genes and their cognate origins. These replicator-initiator pairings are reminiscent of the oriC-dnaA system in bacteria, and a model for the negative regulation of origin activity by a downstream cluster of ORB elements has been recently proposed in haloarchaea. Moreover, comparative genomic analyses have revealed that the mosaics of replicator-initiator pairings in archaeal chromosomes originated from the integration of extrachromosomal elements. This review summarizes the research progress in understanding of archaeal replication origins with particular focus on the utilization, control and evolution of multiple replication origins in haloarchaea.

  20. Optimized Dose Distribution of Gammamed Plus Vaginal Cylinders

    International Nuclear Information System (INIS)

    Supe, Sanjay S.; Bijina, T.K.; Varatharaj, C.; Shwetha, B.; Arunkumar, T.; Sathiyan, S.; Ganesh, K.M.; Ravikumar, M.

    2009-01-01

    Endometrial carcinoma is the most common malignancy arising in the female genital tract. Intracavitary vaginal cuff irradiation may be given alone or with external beam irradiation in patients determined to be at risk for locoregional recurrence. Vaginal cylinders are often used to deliver a brachytherapy dose to the vaginal apex and upper vagina or the entire vaginal surface in the management of postoperative endometrial cancer or cervical cancer. The dose distributions of HDR vaginal cylinders must be evaluated carefully, so that clinical experiences with LDR techniques can be used in guiding optimal use of HDR techniques. The aim of this study was to optimize dose distribution for Gammamed plus vaginal cylinders. Placement of dose optimization points was evaluated for its effect on optimized dose distributions. Two different dose optimization point models were used in this study, namely non-apex (dose optimization points only on periphery of cylinder) and apex (dose optimization points on periphery and along the curvature including the apex points). Thirteen dwell positions were used for the HDR dosimetry to obtain a 6-cm active length. Thus 13 optimization points were available at the periphery of the cylinder. The coordinates of the points along the curvature depended on the cylinder diameters and were chosen for each cylinder so that four points were distributed evenly in the curvature portion of the cylinder. Diameter of vaginal cylinders varied from 2.0 to 4.0 cm. Iterative optimization routine was utilized for all optimizations. The effects of various optimization routines (iterative, geometric, equal times) was studied for the 3.0-cm diameter vaginal cylinder. The effect of source travel step size on the optimized dose distributions for vaginal cylinders was also evaluated. All optimizations in this study were carried for dose of 6 Gy at dose optimization points. For both non-apex and apex models of vaginal cylinders, doses for apex point and three dome

  1. Prediction of External Corrosion for Steel Cylinders--2004 Report

    International Nuclear Information System (INIS)

    Schmoyer, RLS

    2004-01-01

    Depleted uranium hexafluoride (UF 6 ) is stored in over 60,000 steel cylinders at the East Tennessee Technology Park (ETTP) in Oak Ridge, Tennessee, at the Paducah Gaseous Diffusion Plant (PGDP) in Paducah, Kentucky, and at the Portsmouth Gaseous Diffusion Plant (PORTS) in Portsmouth, Ohio. The cylinders range in age from 4 to 53 years. Although when new the cylinders had wall thicknesses specified to within manufacturing tolerances, over the years corrosion has reduced their actual wall thicknesses. The UF 6 Cylinder Project is managed by the United States Department of Energy (DOE) to safely maintain the UF 6 and the cylinders containing it. This report documents activities that address UF 6 Cylinder Project requirements and actions involving forecasting cylinder wall thicknesses. These requirements are delineated in the System Requirements Document (LMES 1997a), and the actions needed to fulfill them are specified in the System Engineering Management Plan (LMES 1997b). The report documents cylinder wall thickness projections based on models fit to ultrasonic thickness (UT) measurement data. UT data is collected at various locations on randomly sampled cylinders. For each cylinder sampled, the minimum UT measurement approximates the actual minimum thickness of the cylinder. Projections of numbers of cylinders expected to fail various thickness criteria are computed from corrosion models relating minimum wall thickness to cylinder age, initial thickness estimates, and cylinder subpopulations defined in terms of plant site, yard, top or bottom storage positions, nominal thickness, etc. In this report, UT data collected during FY03 is combined with UT data collected in earlier years (FY94-FY02), and all of the data is inventoried chronologically and by various subpopulations. The UT data is used to fit models of maximum pit depth and minimum thickness, and the fitted models are used to extrapolate minimum thickness estimates into the future and in turn to compute

  2. Prediction of External Corrosion for Steel Cylinders--2004 Report

    Energy Technology Data Exchange (ETDEWEB)

    Schmoyer, RLS

    2004-07-07

    Depleted uranium hexafluoride (UF{sub 6}) is stored in over 60,000 steel cylinders at the East Tennessee Technology Park (ETTP) in Oak Ridge, Tennessee, at the Paducah Gaseous Diffusion Plant (PGDP) in Paducah, Kentucky, and at the Portsmouth Gaseous Diffusion Plant (PORTS) in Portsmouth, Ohio. The cylinders range in age from 4 to 53 years. Although when new the cylinders had wall thicknesses specified to within manufacturing tolerances, over the years corrosion has reduced their actual wall thicknesses. The UF{sub 6} Cylinder Project is managed by the United States Department of Energy (DOE) to safely maintain the UF{sub 6} and the cylinders containing it. This report documents activities that address UF{sub 6} Cylinder Project requirements and actions involving forecasting cylinder wall thicknesses. These requirements are delineated in the System Requirements Document (LMES 1997a), and the actions needed to fulfill them are specified in the System Engineering Management Plan (LMES 1997b). The report documents cylinder wall thickness projections based on models fit to ultrasonic thickness (UT) measurement data. UT data is collected at various locations on randomly sampled cylinders. For each cylinder sampled, the minimum UT measurement approximates the actual minimum thickness of the cylinder. Projections of numbers of cylinders expected to fail various thickness criteria are computed from corrosion models relating minimum wall thickness to cylinder age, initial thickness estimates, and cylinder subpopulations defined in terms of plant site, yard, top or bottom storage positions, nominal thickness, etc. In this report, UT data collected during FY03 is combined with UT data collected in earlier years (FY94-FY02), and all of the data is inventoried chronologically and by various subpopulations. The UT data is used to fit models of maximum pit depth and minimum thickness, and the fitted models are used to extrapolate minimum thickness estimates into the future and in

  3. UF{sub 6} pressure excursions during cylinder heating

    Energy Technology Data Exchange (ETDEWEB)

    Brown, P.G. [Martin Marietta Energy Systems, Inc., Paducah, KY (United States)

    1991-12-31

    As liquid UF{sub 6} inside a cylinder changes from a liquid to a solid, it forms a porous solid which occupies approximately the same volume as that of the liquid before cooling. Simultaneously as the liquid cools, UF{sub 6} vapor in the cylinder ullage above the liquid desublimes on the upper region of the inner cylinder wall. This solid is a dense, glass-like material which can accumulate to a significant thickness. The thickness of the solid coating on the upper cylinder wall and directly behind the cylinder valve area will vary depending on the conditions during the cooling stage. The amount of time lapsed between UF{sub 6} solidification and UF{sub 6} liquefaction can also affect the UF{sub 6} coating. This is due to the daily ambient heat cycle causing the coating to sublime from the cylinder wall to cooler areas, thus decreasing the thickness. Structural weakening of the dense UF{sub 6} layer also occurs due to cylinder transport vibration and thermal expansion. During cylinder heating, the UF{sub 6} nearest the cylinder wall will liquefy first. As the solid coating behind the cylinder valve begins to liquefy, it results in increased pressure depending upon the available volume for expansion. At the Paducah Gaseous Diffusion Plant (PGDP) during the liquefaction of the UF{sub 6} in cylinders in the UF{sub 6} feed and sampling autoclaves, this pressure increase has resulted in the activation of the systems rupture discs which are rated at 100 pounds per square inch differential.

  4. The ideal dimensions of a Halbach cylinder of finite length

    DEFF Research Database (Denmark)

    Bjørk, Rasmus

    2011-01-01

    In this paper the smallest or optimal dimensions of a Halbach cylinder of a finite length for a given sample volume and desired flux density are determined using numerical modeling and parameter variation. A sample volume that is centered in and shaped as the Halbach cylinder bore but with a poss...

  5. Corotating light cylinders and Alfv\\'en waves

    OpenAIRE

    Gourgouliatos, K. N.; Lynden-Bell, D.

    2010-01-01

    Exact relativistic force free fields with cylindrical symmetry are explored. Such fields are generated in the interstellar gas via their connection to pulsar magnetospheres both inside and outside their light cylinders. The possibility of much enhanced interstellar fields wound on cylinders of Solar system dimensions is discussed but these are most likely unstable.

  6. Facial and eye injury following a fridge cylinder gas explosion

    African Journals Online (AJOL)

    and then diclofenac (Cataflam) tablets 50mg 8 hourly, metronidazole tablets 200mg 8 hourly and cefuroxime. (Zinnat) ... The mechanism of cylinder gas explosion injury are mainly divided into 4 stages [1]. 1. ... Another possible mechanism may be secondary injury. Facial abrasion from flying fragment of the gas cylinder.

  7. Torsional vibrations of infinite composite poroelastic cylinders | Shah ...

    African Journals Online (AJOL)

    The displacements of second and third torsional modes are determined and presented graphically for the ratio of radius of composite poroelastic solid cylinder to the radius of the inner solid cylinder. Results of previous works are shown as special case of the present analysis. By ignoring liquid effects, the results of purely ...

  8. Minimization of material volume of three layer compound cylinder ...

    African Journals Online (AJOL)

    This paper introduces the methodology for minimization of volume of shrink-fitted three layer compound cylinder and to get equal maximum hoop stresses in all the cylinders. The analytical results are validated in comparison with FEM in ANSYS Workbench. Both the results agree with each other. Thus methodology can be ...

  9. Strength Tests on Paper Cylinder in Compression, Bending and Shear

    Science.gov (United States)

    Rhodes, Richard V; Lundquist, Eugene E

    1931-01-01

    Static tests on paper cylinders were conducted at the Langley Memorial Aeronautical Laboratory at Langley Field, Virginia, to obtain qualitative information in connection with a study of the strength of stressed-skin fuselages. The effects of radius-thickness ratio and bulkhead spacing were investigated with the cylinders in compression, bending, combined bending and shear, and torsion.

  10. Clean Air Program : cylinder issues associated with alternative fuels

    Science.gov (United States)

    1999-01-01

    A number of incidents of compressed natural gas (CNG) cylinder leaks have occurred while transit buses were either in service or at a bus maintenance facility. This study was initiated to determine the degree to which cylinder problems still exist in...

  11. Robust cylinder fitting in three-dimensional point cloud data

    NARCIS (Netherlands)

    Nurunnabi, Abdul; Sadahiro, Yukio; Lindenbergh, R.C.

    2017-01-01

    This paper investigates the problems of cylinder fitting in laser scanning three-dimensional Point Cloud Data (PCD). Most existing methods require full cylinder data, do not study the presence of outliers, and are not statistically robust. But especially mobile laser scanning often has incomplete

  12. Curing A Large Composite Cylinder Without An Autoclave

    Science.gov (United States)

    Frazer, Robert E.

    1992-01-01

    Proposed technique provides application of heat and pressure to cure fiber-wound composite cylinder too large to fit in autoclave. Tube wound around cylinder applies pressure. Blanket distributes pressure. Pressure expels gas bubbles from material. Heat applied by conventional methods.

  13. 30 CFR 57.4601 - Oxygen cylinder storage.

    Science.gov (United States)

    2010-07-01

    ....4601 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-UNDERGROUND METAL AND NONMETAL MINES Fire Prevention and Control Welding/cutting/compressed Gases § 57.4601 Oxygen cylinder storage. Oxygen cylinders shall...

  14. 30 CFR 56.4601 - Oxygen cylinder storage.

    Science.gov (United States)

    2010-07-01

    ....4601 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-SURFACE METAL AND NONMETAL MINES Fire Prevention and Control Welding/cutting/compressed Gases § 56.4601 Oxygen cylinder storage. Oxygen cylinders shall not be...

  15. Faraday effect in hollow quantum cylinder of finite thickness

    International Nuclear Information System (INIS)

    Ismailov, T.G.; Jabrailova, G.G.

    2009-01-01

    The interband Faraday rotation in hollow quantum cylinder of finite thickness is theoretically investigated. Faraday rotation in the dependence on incident light energy for different values of cylinder thickness. It is seen that the resonance peaks appear on Faraday rotation curve. The roles of selection are obtained

  16. Investigation on carbon nanomaterials: Coaxial CNT-cylinders and ...

    Indian Academy of Sciences (India)

    The macroscopic coaxial carbon cylinders (dia. ∼ 0.5 cm with varying lengths, ∼ 7–10 cm) consisting of aligned carbon nanotube (CNT) stacks have been prepared by controlled spray pyrolysis method. The coaxial carbon cylinders of CNT stacks have been formed directly inside the quartz tube. Another study is done on ...

  17. Investigation on carbon nanomaterials: Coaxial CNT-cylinders and ...

    Indian Academy of Sciences (India)

    Wintec

    Abstract. The macroscopic coaxial carbon cylinders (dia. ~0⋅5 cm with varying lengths, ~7–10 cm) consisting of aligned carbon nanotube (CNT) stacks have been prepared by controlled spray pyrolysis method. The coaxial carbon cylinders of CNT stacks have been formed directly inside the quartz tube. Another study is ...

  18. Mechanical Integrity of Copper Canister Lid and Cylinder. Sensitivity study

    International Nuclear Information System (INIS)

    Karlsson, Marianne

    2002-08-01

    This report is part of a study of the mechanical integrity of canisters used for disposal of nuclear fuel waste. The overall objective is to determine and ensure the static and long-term strength of the copper canister lid and cylinder casing. The canisters used for disposal nuclear fuel waste of type BWR consists of an inner part (insert) of ductile cast iron and an outer part of copper. The copper canister is to provide a sealed barrier between the contents of the canister and the surroundings. The study in this report complements the finite element analyses performed in an earlier study. The analyses aim to evaluate the sensitivity of the canister to tolerances regarding the gap between the copper cylinder and the cast iron insert. Since great uncertainties regarding the material's long term creep properties prevail, analyses are also performed to evaluate the effect of different creep data on the resulting strain and stress state. The report analyses the mechanical response of the lid and flange of the copper canister when subjected to loads caused by pressure from swelling bentonite and from groundwater at a depth of 500 meter. The loads acting on the canister are somewhat uncertain and the cases investigated in this report are possible cases. Load cases analysed are: Pressure 15 MPa uniformly distributed on lid and 5 MPa uniformly distributed on cylinder; Pressure 5 MPa uniformly distributed on lid and 15 MPa uniformly distributed on cylinder; Pressure 20 MPa uniformly distributed on lid and cylinder; and Side pressures 10 MPa and 20 MPa uniformly distributed on part of the cylinder. Creep analyses are performed for two of the load cases. For all considered designs high principal stresses appear on the outside of the copper cylinder in the region from the weld down to the level of the lid lower edge. Altering the gap between lid and cylinder and/or between cylinder and insert only marginally affects the resulting stress state. Fitting the lid in the cylinder

  19. Modeling a High Explosive Cylinder Experiment

    Science.gov (United States)

    Zocher, Marvin A.

    2017-06-01

    Cylindrical assemblies constructed from high explosives encased in an inert confining material are often used in experiments aimed at calibrating and validating continuum level models for the so-called equation of state (constitutive model for the spherical part of the Cauchy tensor). Such is the case in the work to be discussed here. In particular, work will be described involving the modeling of a series of experiments involving PBX-9501 encased in a copper cylinder. The objective of the work is to test and perhaps refine a set of phenomenological parameters for the Wescott-Stewart-Davis reactive burn model. The focus of this talk will be on modeling the experiments, which turned out to be non-trivial. The modeling is conducted using ALE methodology.

  20. Topograph for inspection of engine cylinder walls.

    Science.gov (United States)

    Franz, S; Leonhardt, K; Windecker, R; Tiziani, H J

    1999-12-20

    The microstructural inspection of engine cylinder walls is an important task for quality management in the automotive industry. Until recently, mainly tactile methods were used for this purpose. We present an optical instrument based on microscopic fringe projection that permits fast, reliable, and nondestructive measurements of microstructure. The field of view is 0.8 mm x 1.2 mm, with a spatial sampling of 1100 x 700 pixels. In contrast to conventional tactile sensors, the optical method provides fast in situ three-dimensional surface characterizations that provide more information about the surface than do line profiles. Measurements are presented, and advantages of this instrument for characterization of a surface are discussed.

  1. Switchable and Tunable Aerodynamic Drag on Cylinders

    Science.gov (United States)

    Guttag, Mark; Lopéz Jiménez, Francisco; Upadhyaya, Priyank; Kumar, Shanmugam; Reis, Pedro

    We report results on the performance of Smart Morphable Surfaces (Smporhs) that can be mounted onto cylindrical structures to actively reduce their aerodynamic drag. Our system comprises of an elastomeric thin shell with a series of carefully designed subsurface cavities that, once depressurized, lead to a dramatic deformation of the surface topography, on demand. Our design is inspired by the morphology of the giant cactus (Carnegiea gigantea) which possesses an array of axial grooves, thought to help reduce aerodynamic drag, thereby enhancing the structural robustness of the plant under wind loading. We perform systematic wind tunnel tests on cylinders covered with our Smorphs and characterize their aerodynamic performance. The switchable and tunable nature of our system offers substantial advantages for aerodynamic performance when compared to static topographies, due to their operation over a wider range of flow conditions.

  2. Mechanical Cushion Design Influence on Cylinder Dynamics

    DEFF Research Database (Denmark)

    Borghi, Massimo; Milani, Massimo; Conrad, Finn

    2005-01-01

    The paper deals with the simulation and the experimental verification of the dynamic behaviour of a linear actuator equipped with different configurations of mechanical cushion. A numerical model, developed and tailored to describe the influence of different modulation of the discharged flow....... experimental comparison, involving the piston velocity and the cylinder chambers pressure. After, with the aim of highlighting the effect of mechanical cushions design on a two effect linear actuator dynamic performances, the characteristics modulation of four alternative cushioning systems are determined...... and deeply analyzed. Finally, a sensitivity analysis about the influence of the variation of the main geometrical parameters is introduced and, thanks to the introduction of some dimensional and non-dimensional parameters of engineering interest, some useful guidelines in selecting the most effective cushion...

  3. Mechanical Cushion Design Influence on Cylinder Dynamics

    DEFF Research Database (Denmark)

    Borghi, Massimo; Milani, Massimo; Conrad, Finn

    2005-01-01

    . experimental comparison, involving the piston velocity and the cylinder chambers pressure. After, with the aim of highlighting the effect of mechanical cushions design on a two effect linear actuator dynamic performances, the characteristics modulation of four alternative cushioning systems are determined......The paper deals with the simulation and the experimental verification of the dynamic behaviour of a linear actuator equipped with different configurations of mechanical cushion. A numerical model, developed and tailored to describe the influence of different modulation of the discharged flow......-rate (and of the correspondent discharging orifice design) on the cushioning characteristics variation is firstly introduced. Then, with respect to the case of the cylindrical cushioning engagement, both the reliability and the limits of the numerical approach are highlighted through a numerical vs...

  4. The Role of the N-Terminal Domains of Bacterial Initiator DnaA in the Assembly and Regulation of the Bacterial Replication Initiation Complex

    Science.gov (United States)

    Zawilak-Pawlik, Anna; Nowaczyk, Małgorzata; Zakrzewska-Czerwińska, Jolanta

    2017-01-01

    The primary role of the bacterial protein DnaA is to initiate chromosomal replication. The DnaA protein binds to DNA at the origin of chromosomal replication (oriC) and assembles into a filament that unwinds double-stranded DNA. Through interaction with various other proteins, DnaA also controls the frequency and/or timing of chromosomal replication at the initiation step. Escherichia coli DnaA also recruits DnaB helicase, which is present in unwound single-stranded DNA and in turn recruits other protein machinery for replication. Additionally, DnaA regulates the expression of certain genes in E. coli and a few other species. Acting as a multifunctional factor, DnaA is composed of four domains that have distinct, mutually dependent roles. For example, C-terminal domain IV interacts with double-stranded DnaA boxes. Domain III drives ATP-dependent oligomerization, allowing the protein to form a filament that unwinds DNA and subsequently binds to and stabilizes single-stranded DNA in the initial replication bubble; this domain also interacts with multiple proteins that control oligomerization. Domain II constitutes a flexible linker between C-terminal domains III–IV and N-terminal domain I, which mediates intermolecular interactions between DnaA and binds to other proteins that affect DnaA activity and/or formation of the initiation complex. Of these four domains, the role of the N-terminus (domains I–II) in the assembly of the initiation complex is the least understood and appears to be the most species-dependent region of the protein. Thus, in this review, we focus on the function of the N-terminus of DnaA in orisome formation and the regulation of its activity in the initiation complex in different bacteria. PMID:28489024

  5. Rotating cylinder drag balance with application to riblets

    Science.gov (United States)

    Hall, T.; Joseph, D.

    2000-12-01

    Experimental results are reported and discussed for a rotating cylinder drag balance designed to predict drag reduction by surfaces like riblets. The apparatus functions by measuring the torque applied to the inner cylinder by a fluid, such as water, that is set in motion by the controlled rotation of the outer cylinder. The instrument was validated by calibration for laminar flow and comparison of turbulent flow results to the those of G. I. Taylor. The ability to predict drag reduction was demonstrated by testing 114 m symmetric sawtooth riblets, which gave a maximum reduction of about 5% and an overall drag reduction range of 5cylinder surface and to use cylinders for which the curvature of the flow is minimized.

  6. Magnetic susceptibility in the edged topological disordered nanoscopic cylinder

    International Nuclear Information System (INIS)

    Faizabadi, Edris; Omidi, Mahboubeh

    2011-01-01

    The effects of edged topological disorder on magnetic susceptibility are investigated in a nanoscopic cylinder threaded by a magnetic flux. Persistent current versus even or odd number of electrons shows different signs in ordered and disordered cylinders and also in short or long ones. In addition, temperature-averaged susceptibility has only diamagnetic signs in strong regimes and it is associated with paramagnetic signs in ordered and weak disordered ones. Besides, in an edged topological disordered cylinder, the temperature-averaged susceptibility decreases by raising the temperature somewhat and then increasing initiates and finally at high temperature tends to zero as the ordered one. - Research highlights: → Magnetic susceptibility in one-dimensional topological disordered quantum ring. → Edged topological disorder effect on magnetic susceptibility in nanoscopic cylinder. → Edged topological disorder effect on temperature-averaged susceptibility in cylinder.

  7. Network design for cylinder gas distribution

    Directory of Open Access Journals (Sweden)

    Tejinder Pal Singh

    2015-01-01

    Full Text Available Purpose: Network design of the supply chain is an important and strategic aspect of logistics management. In this paper, we address the network design problem specific to packaged gases (cylinder supply chain. We propose an integrated framework that allows for the determination of the optimal facility locations, the filling plant production capacities, the inventory at plants and hubs, and the number of packages to be routed in primary and secondary transportation. Design/methodology/approach: We formulate the problem as a mixed integer program and then develop a decomposition approach to solve it. We illustrate the proposed framework with numerical examples from real-life packaged gases supply chain. The results show that the decomposition approach is effective in solving a broad range of problem sizes. Findings: The main finding of this paper is that decomposing the network design problem into two sub-problems is very effective to tackle the real-life large scale network design problems occurring in cylinder gas distribution by optimizing strategic and tactical decisions and approximating the operational decisions. We also benchmark the results from the decomposition approach by solving the complete packaged gases network design model for smaller test cases. Originality/value: The main contribution of our work is that it integrates supply chain network design decisions without fixing the fillings plant locations with inventory and resource allocation decisions required at the plants. We also consider the transportation costs for the entire supply chain including the transhipment costs among different facilities by deciding the replenishment frequency.

  8. The Federal Cylinder Project: A Guide to Field Cylinder Collections in Federal Agencies. Volume 8, Early Anthologies.

    Science.gov (United States)

    Lee, Dorothy Sara, Ed; And Others

    This catalog describes wax cylinder recordings of music collected by two pioneers in ethnomusicology. The 101 cylinders in the Benjamin Ives Gilman Collection recorded at the 1893 World's Columbian Exposition in Chicago contain Fijian, Samoan, Uvean, Javanese, Turkish, and Kwakiutl or Vancouver Island Indian music. The Gilman Collection is…

  9. Design for a Simple and Inexpensive Cylinder-within-a-Cylinder Gradient Maker for the Undergraduate Biochemistry Laboratory

    Science.gov (United States)

    Sims, Paul A.; O'Mealey, Gary B.; Khan, Nabeel A.; Larabee, Chelsea M.

    2011-01-01

    A design for a simple and inexpensive gradient maker is described. The gradient maker is assembled by (i) cutting the tops off two plastic bottles of differing diameters to produce two cylinders with intact bottoms; (ii) drilling a small hole toward the bottom of the smaller diameter cylinder and plugging the hole with a size 00 cork stopper; and…

  10. A methodology to identify the intake charge cylinder-to-cylinder distribution in turbocharged direct injection Diesel engines

    Science.gov (United States)

    Luján, José M.; Galindo, José; Serrano, José R.; Pla, Benjamín

    2008-06-01

    Exhaust gas recirculation (EGR) is currently the most important NOx emission control system. During the last few years the EGR rate has increased progressively as pollutant emission regulations have become more restrictive. High EGR rate levels have given the effect of the unsuitable EGR and air distribution between cylinders away, which causes undesirable engine behavior. In this sense, the study of the EGR distribution between cylinders achieves high importance. However, despite the fact that the EGR is continuously under study, not many studies have been undertaken to approach its distribution between cylinders. In concordance with the aspects outlined before, the aim of this paper is to propose a methodology that permits us to identify the EGR cylinder-to-cylinder dispersion in a commercial engine. In order to achieve this objective, experimental tests have been combined with both one-dimensional and three-dimensional fluid dynamic models.

  11. Application of the exact solution for scattering by an infinite cylinder to the estimation of scattering by a finite cylinder.

    Science.gov (United States)

    Wang, R T; van de Hulst, H C

    1995-05-20

    A new algorithm for cylindrical Bessel functions that is similar to the one for spherical Bessel functions allows us to compute scattering functions for infinitely long cylinders covering sizes ka = 2πa/λ up to 8000 through the use of only an eight-digit single-precision machine computation. The scattering function and complex extinction coefficient of a finite cylinder that is seen near perpendicular incidence are derived from those of an infinitely long cylinder by the use of Huygens's principle. The result, which contains no arbitrary normalization factor, agrees quite well with analog microwave measurements of both extinction and scattering for such cylinders, even for an aspect ratio p = l/(2a) as low as 2. Rainbows produced by cylinders are similar to those for spherical drops but are brighter and have a lower contrast.

  12. DNA Sequences Proximal to Human Mitochondrial DNA Deletion Breakpoints Prevalent in Human Disease Form G-quadruplexes, a Class of DNA Structures Inefficiently Unwound by the Mitochondrial Replicative Twinkle Helicase*

    Science.gov (United States)

    Bharti, Sanjay Kumar; Sommers, Joshua A.; Zhou, Jun; Kaplan, Daniel L.; Spelbrink, Johannes N.; Mergny, Jean-Louis; Brosh, Robert M.

    2014-01-01

    Mitochondrial DNA deletions are prominent in human genetic disorders, cancer, and aging. It is thought that stalling of the mitochondrial replication machinery during DNA synthesis is a prominent source of mitochondrial genome instability; however, the precise molecular determinants of defective mitochondrial replication are not well understood. In this work, we performed a computational analysis of the human mitochondrial genome using the “Pattern Finder” G-quadruplex (G4) predictor algorithm to assess whether G4-forming sequences reside in close proximity (within 20 base pairs) to known mitochondrial DNA deletion breakpoints. We then used this information to map G4P sequences with deletions characteristic of representative mitochondrial genetic disorders and also those identified in various cancers and aging. Circular dichroism and UV spectral analysis demonstrated that mitochondrial G-rich sequences near deletion breakpoints prevalent in human disease form G-quadruplex DNA structures. A biochemical analysis of purified recombinant human Twinkle protein (gene product of c10orf2) showed that the mitochondrial replicative helicase inefficiently unwinds well characterized intermolecular and intramolecular G-quadruplex DNA substrates, as well as a unimolecular G4 substrate derived from a mitochondrial sequence that nests a deletion breakpoint described in human renal cell carcinoma. Although G4 has been implicated in the initiation of mitochondrial DNA replication, our current findings suggest that mitochondrial G-quadruplexes are also likely to be a source of instability for the mitochondrial genome by perturbing the normal progression of the mitochondrial replication machinery, including DNA unwinding by Twinkle helicase. PMID:25193669

  13. Three-dimensional structure of N-terminal domain of DnaB helicase and helicase-primase interactions in Helicobacter pylori.

    Directory of Open Access Journals (Sweden)

    Tara Kashav

    2009-10-01

    Full Text Available Replication initiation is a crucial step in genome duplication and homohexameric DnaB helicase plays a central role in the replication initiation process by unwinding the duplex DNA and interacting with several other proteins during the process of replication. N-terminal domain of DnaB is critical for helicase activity and for DnaG primase interactions. We present here the crystal structure of the N-terminal domain (NTD of H. pylori DnaB (HpDnaB helicase at 2.2 A resolution and compare the structural differences among helicases and correlate with the functional differences. The structural details of NTD suggest that the linker region between NTD and C-terminal helicase domain plays a vital role in accurate assembly of NTD dimers. The sequence analysis of the linker regions from several helicases reveals that they should form four helix bundles. We also report the characterization of H. pylori DnaG primase and study the helicase-primase interactions, where HpDnaG primase stimulates DNA unwinding activity of HpDnaB suggesting presence of helicase-primase cohort at the replication fork. The protein-protein interaction study of C-terminal domain of primase and different deletion constructs of helicase suggests that linker is essential for proper conformation of NTD to interact strongly with HpDnaG. The surface charge distribution on the primase binding surface of NTDs of various helicases suggests that DnaB-DnaG interaction and stability of the complex is most probably charge dependent. Structure of the linker and helicase-primase interactions indicate that HpDnaB differs greatly from E.coli DnaB despite both belong to gram negative bacteria.

  14. RecBCD (Exonuclease V) is inhibited by DNA adducts produced by cisplatin and ultraviolet light.

    Science.gov (United States)

    Leung, Wai Y; Chung, Long H; Kava, Hieronimus W; Murray, Vincent

    2018-01-01

    The presence of adducts on the DNA double-helix can have major consequences for the efficient functioning of DNA repair enzymes. E. coli RecBCD (exonuclease V) is involved in recombinational repair of double-strand breaks that are caused by defective DNA replication, DNA damaging agents and other factors. The holoenzyme possesses a bipolar helicase activity which helps unwind DNA from both 3'- and 5'-directions and is coupled with a potent exonuclease activity that is also capable of digesting DNA from both 3'- and 5'-ends. In this study, DNA sequences were damaged with cisplatin or UV followed by RecBCD treatment. DNA damaging agents such as cisplatin and UV induce the formation of intrastrand adducts in the DNA template. It was demonstrated that RecBCD degradation was inhibited by either cisplatin-damaged or UV-damaged DNA sequences. This is the first occasion that RecBCD has been demonstrated to be inhibited by DNA adducts induced by cisplatin or UV. In addition, we quantified the amounts of DNA remaining after RecBCD treatment and observed that the level of inhibition was concentration and dose dependent. A DNA-targeted 9-aminoacridinecarboxamide cisplatin analogue was also found to inhibit RecBCD activity. Crown Copyright © 2017. Published by Elsevier Inc. All rights reserved.

  15. Vortex suppression in the wake of counter rotating cylinders

    Science.gov (United States)

    Dewey, Peter; Smits, Alexander J.

    2009-11-01

    Digital particle image velocimetry is used to study the flow past a pair of counter rotating cylinders placed side-by-side normal to the freestream flow direction. The Reynolds numbers based on cylinder diameter is varied from 100 to 200 and gap-to-diameter ratios of 1, 3 and 5 are considered. An unsteady wake consisting of a pair of von K'arm'an vortex streets is present in the flow field when the cylinders are rotated below a critical value. Above this critical value, counter rotation of the cylinders suppresses vortex formation. The critical rotational speed varies only slightly with Reynolds number but exhibits a strong dependence on the gap-to-diameter ratio. As the gap-to-diameter ratio increases, the critical rotational speed approaches values expected to suppress vortex formation for a single rotating cylinder, indicating that the wakes of the cylinder pair have more interaction for small gap-to-diameter ratios. At sufficiently high rotational speeds the streamlines around the cylinder pair resemble a doublet potential flow. The experiments were inspired by the computations performed by Andy Chan and Antony Jameson at Stanford University.

  16. Habitat Demonstration Unit (HDU) Vertical Cylinder Habitat

    Science.gov (United States)

    Howe, Alan; Kennedy, Kriss J.; Gill, Tracy R.; Tri, Terry O.; Toups, Larry; Howard, Robert I.; Spexarth, Gary R.; Cavanaugh, Stephen; Langford, William M.; Dorsey, John T.

    2014-01-01

    NASA's Constellation Architecture Team defined an outpost scenario optimized for intensive mobility that uses small, highly mobile pressurized rovers supported by portable habitat modules that can be carried between locations of interest on the lunar surface. A compact vertical cylinder characterizes the habitat concept, where the large diameter maximizes usable flat floor area optimized for a gravity environment and allows for efficient internal layout. The module was sized to fit into payload fairings for the Constellation Ares V launch vehicle, and optimized for surface transport carried by the All-Terrain Hex-Limbed Extra-Terrestrial Explorer (ATHLETE) mobility system. Launch and other loads are carried through the barrel to a top and bottom truss that interfaces with a structural support unit (SSU). The SSU contains self-leveling feet and docking interfaces for Tri-ATHLETE grasping and heavy lift. A pressurized module needed to be created that was appropriate for the lunar environment, could be easily relocated to new locations, and could be docked together in multiples for expanding pressurized volume in a lunar outpost. It was determined that horizontally oriented pressure vessels did not optimize floor area, which takes advantage of the gravity vector for full use. Hybrid hard-inflatable habitats added an unproven degree of complexity that may eventually be worked out. Other versions of vertically oriented pressure vessels were either too big, bulky, or did not optimize floor area. The purpose of the HDU vertical habitat module is to provide pressurized units that can be docked together in a modular way for lunar outpost pressurized volume expansion, and allow for other vehicles, rovers, and modules to be attached to the outpost to allow for IVA (intra-vehicular activity) transfer between them. The module is a vertically oriented cylinder with a large radius to allow for maximal floor area and use of volume. The modular, 5- m-diameter HDU vertical habitat

  17. Heat transfer measurements for Stirling machine cylinders

    Science.gov (United States)

    Kornhauser, Alan A.; Kafka, B. C.; Finkbeiner, D. L.; Cantelmi, F. C.

    1994-01-01

    The primary purpose of this study was to measure the effects of inflow-produced heat turbulence on heat transfer in Stirling machine cylinders. A secondary purpose was to provide new experimental information on heat transfer in gas springs without inflow. The apparatus for the experiment consisted of a varying-volume piston-cylinder space connected to a fixed volume space by an orifice. The orifice size could be varied to adjust the level of inflow-produced turbulence, or the orifice plate could be removed completely so as to merge the two spaces into a single gas spring space. Speed, cycle mean pressure, overall volume ratio, and varying volume space clearance ratio could also be adjusted. Volume, pressure in both spaces, and local heat flux at two locations were measured. The pressure and volume measurements were used to calculate area averaged heat flux, heat transfer hysteresis loss, and other heat transfer-related effects. Experiments in the one space arrangement extended the range of previous gas spring tests to lower volume ratio and higher nondimensional speed. The tests corroborated previous results and showed that analytic models for heat transfer and loss based on volume ratio approaching 1 were valid for volume ratios ranging from 1 to 2, a range covering most gas springs in Stirling machines. Data from experiments in the two space arrangement were first analyzed based on lumping the two spaces together and examining total loss and averaged heat transfer as a function of overall nondimensional parameter. Heat transfer and loss were found to be significantly increased by inflow-produced turbulence. These increases could be modeled by appropriate adjustment of empirical coefficients in an existing semi-analytic model. An attempt was made to use an inverse, parameter optimization procedure to find the heat transfer in each of the two spaces. This procedure was successful in retrieving this information from simulated pressure-volume data with artificially

  18. Competitive dynamics of two erosion patterns around a cylinder

    Science.gov (United States)

    Lachaussée, F.; Bertho, Y.; Morize, C.; Sauret, A.; Gondret, P.

    2018-01-01

    We investigate experimentally the local erosion of a granular bed near a fixed vertical cylinder that emerges from the bed. The onset of erosion arising at the base of the cylinder and usually ascribed to the wrapping horseshoe vortex is determined and rationalized by a flow contraction effect. We report another erosion pattern visible downstream of the cylinder that consists of two side-by-side elongated holes. This pattern is observed for flow regimes close to the horseshoe scour onset, whose growth usually inhibits its spatiotemporal development.

  19. CYLINDER OF THE DISPOSABLE MASS EXCHANGE DEVICE FOR HEMOSORPTION

    Directory of Open Access Journals (Sweden)

    F. I. Kazakov

    2015-01-01

    Full Text Available BACKGROUND. Hemocarboperfusion, previously widely used in our country, can universally pass out of use due to the lack of industrial production of disposable mass exchange devices.MATERIAl AND METHODS. Physicochemical properties of materials and design features of the body samples elements of various sizes have been studied.RESULTS. The elements and materials properties of the hemosorption mass exchanger cylinder have been studied. Hydrodynamic parameters of manipulation using the developed cylinders at different perfusion rates have been studied in bench experiments.CONCLUSION. The original cylinder of the disposable mass exchange device for hemosorption, which meets the current clinical needs, has been developed. 

  20. Oscillatory flow about a cylinder pair with unequal radii

    Energy Technology Data Exchange (ETDEWEB)

    Coenen, W, E-mail: wcoenen@ing.uc3m.es [Área de Mecánica de Fluidos, Universidad Carlos III de Madrid, Avenida Universidad 30, E-28911 Leganés, Madrid (Spain)

    2013-10-15

    We consider the oscillating flow about a pair of circular cylinders of unequal diameter. In addition to the relative size of the cylinders, the distance between them can be varied, as can the angle that the undisturbed oscillatory flow makes with the line joining the cylinder centres. For small-amplitude vibrations a time-independent, or steady streaming, motion develops that persists beyond the Stokes layer that forms at the solid boundary. This persistent streaming is considered for large values of a suitably defined streaming Reynolds number. (paper)

  1. Flow instability in flow past O-grooved circular cylinder

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jaehee; Yang, Kyungsoo [Inha University, Inchun (Korea, Republic of)

    2015-04-15

    This study was devoted to elucidating the change in the flow characteristics of a laminar flow past a circular cylinder by modifying the cylinder shape with O-grooves. A numerical analysis was performed in a two-dimensional framework. The cylinder was represented using an immersed boundary method and marker particles on a Cartesian grid system. The number and locations of the O-grooves were the key parameters. An analysis of the flow pattern and flow induced forces was performed at Re = 40 and 50. In addition, we calculated the critical Reynolds number depending on the number of O-grooves and their locations.

  2. Electromagnetic Fields at the Surface of Human-Body Cylinders

    DEFF Research Database (Denmark)

    Kammersgaard, Nikolaj Peter Iversen; Kvist, Søren H.; Thaysen, Jesper

    2016-01-01

    The electromagnetic fields around an infinitely long cylinder with different material parameters are analyzed. The cylinder is modeled as muscle, skin, fat, and perfect electric conductor respectively. The cylinder is illuminated by a plane wave incident from different angles and with both...... transverse electric and transverse magnetic polarization. The results show that the material assumption when modeling the human body as a homogeneous material is very important. Furthermore, it is shown that one assumption might lead to higher fields for a specific polarization, angle of incidence...

  3. Coulomb problem on single- and double-wall cylinders

    International Nuclear Information System (INIS)

    Deinega, Alexei; Voronova, Nina; Lozovik, Yurii

    2012-01-01

    In this paper we calculate the energies of ground and excited states of two opposite charge carriers confined on a single- or double-wall cylindrical surface. A nontrivial dependence of excited state energies on cylinder radius value (for the case of a single-wall cylinder) is found, and the explanation of this behavior is based on symmetry properties of the corresponding wavefunctions. The crossover from a one-dimensional problem to a two-dimensional one with increase of the radius value is discussed in detail. For the double-wall cylinder, we obtain and analyze the dependence of ground state energy on interwall distance and ratio between particle masses. (paper)

  4. Flow around a confined cylinder: LES and PIV study

    Directory of Open Access Journals (Sweden)

    Palkin Egor

    2017-01-01

    Full Text Available We study the flow over a cylinder placed between two parallel rigid walls using Large-eddy simulations and Particle Image Velocimetry. The Reynolds number based on the inflow velocity and diameter of the cylinder is 3750 corresponding to the subcritical regime with laminar separation. Three-dimensional visualization shows the presence of the horseshoe vortex system prior to the cylinder. The comparison of time-averaged velocity fields and fluctuations shows good agreement between simulations and experiments. Spectral analysis suggests the presence of low-frequency modulations of the recirculating bubble.

  5. Cylinder gauge measurement using a position sensitive detector

    International Nuclear Information System (INIS)

    St John, W. Doyle

    2007-01-01

    A position sensitive detector (PSD) has been used to determine the diameter of cylindrical pins based on the shift in a laser beam's centroid. The centroid of the light beam is defined here as the weighted average of position by the local intensity. A shift can be observed in the centroid of an otherwise axially symmetric light beam, which is partially obstructed. Additionally, the maximum shift in the centroid is a unique function of the obstructing cylinder diameter. Thus to determine the cylinder diameter, one only needs to detect this maximum shift as the cylinder is swept across the beam

  6. Interaction of hnRNP A1 with telomere DNA G-quadruplex structures studied at the single molecule level

    DEFF Research Database (Denmark)

    Krüger, Asger Christian; Raarup, Merete Krog; Nielsen, Morten Muhlig

    2010-01-01

    G-rich telomeric DNA sequences can form G-quadruplex structures. The heterogeneous nuclear ribonucleoprotein A1 (hnRNP A1) and a shortened derivative (UP1) are active in telomere length regulation, and it has been reported that UP1 can unwind G-quadruplex structures. Here, we investigate...... the interaction of hnRNP A1 with G-quadruplex DNA structures containing the human telomere repeat (TTAGGG) by gel retardation assays, ensemble fluorescence energy transfer (FRET) spectroscopy, and single molecule FRET microscopy. Our biochemical experiments show that hnRNP A1 binds well to the G...... to the previously reported crystal structures of UP1-telomere DNA complexes where the DNA oligo within the protein-DNA complex is in a fully open conformation....

  7. Modal Structures in flow past a cylinder

    Science.gov (United States)

    Murshed, Mohammad

    2017-11-01

    With the advent of data, there have been opportunities to apply formalism to detect patterns or simple relations. For instance, a phenomenon can be defined through a partial differential equation which may not be very useful right away, whereas a formula for the evolution of a primary variable may be interpreted quite easily. Having access to data is not enough to move on since doing advanced linear algebra can put strain on the way computations are being done. A canonical problem in the field of aerodynamics is the transient flow past a cylinder where the viscosity can be adjusted to set the Reynolds number (Re). We observe the effect of the critical Re on the certain modes of behavior in time scale. A 2D-velocity field works as an input to analyze the modal structure of the flow using the Proper Orthogonal Decomposition and Koopman Mode/Dynamic Mode Decomposition. This will enable prediction of the solution further in time (taking into account the dependence on Re) and help us evaluate and discuss the associated error in the mechanism.

  8. Stability of a rolling fluid filled cylinder

    Science.gov (United States)

    Supekar, Rohit; Panchagnula, Mahesh

    2014-11-01

    We present an analytical solution to the problem of a fluid filled hollow cylindrical shell rolling on an inclined plane and then investigate the temporal stability of the system using linear stability analysis. We study the motion in two dimensions by analyzing the interaction between the fluid and the hollow cylinder. We show that the terminal state is associated with a constant acceleration, similar to a rigid body motion. Surprisingly, it is independent of the liquid viscosity and only depends on the ratio of the mass of the shell to the mass of the fluid contained (say, πm) . We analyze this base flow for its stability behavior using the frozen-time approximation. In this approach, we treat time as a parameter, the evolution of which causes the flow to transition from a stable to an unstable state. The point of neutral stability is noted and the spatial modes that show the maximum growth rate are analyzed. It was observed that instability sets in due to long wavelength axial waves, which are transverse to the flow direction. We find a critical Reynolds number based on the time to instability, above which the flow becomes unstable. Again, this Reynolds number appears to be only a function of πm.

  9. Reluctance Machine for a Hollow Cylinder Flywheel

    Directory of Open Access Journals (Sweden)

    Magnus Hedlund

    2017-03-01

    Full Text Available A hollow cylinder flywheel rotor with a novel outer rotor switched reluctance machine (SRM mounted on the interior rim is presented, with measurements, numerical analysis and analytical models. Practical experiences from the construction process are also discussed. The flywheel rotor does not have a shaft and spokes and is predicted to store 181 Wh / kg at ultimate tensile strength (UTS according to simulations. The novel SRM is an axial flux machine, chosen due to its robustness and tolerance for high strain. The computed maximum tip speed of the motor at UTS is 1050 m / s . A small-scale proof-of-concept electric machine prototype has been constructed, and the machine inductance has been estimated from measurements of voltage and current and compared against results from analytical models and finite element analysis (FEA. The prototype measurements were used to simulate operation during maximal speed for a comparison towards other high-speed electric machines, in terms of tip speed and power. The mechanical design of the flywheel was performed with an analytical formulation assuming planar stress in concentric shells of orthotropic (unidirectionally circumferentially wound carbon composites. The analytical approach was verified with 3D FEA in terms of stress and strain.

  10. Ancient DNA

    DEFF Research Database (Denmark)

    Willerslev, Eske; Cooper, Alan

    2004-01-01

    ancient DNA, palaeontology, palaeoecology, archaeology, population genetics, DNA damage and repair......ancient DNA, palaeontology, palaeoecology, archaeology, population genetics, DNA damage and repair...

  11. Structure and function of DnaA N-terminal domains: specific sites and mechanisms in inter-DnaA interaction and in DnaB helicase loading on oriC.

    Science.gov (United States)

    Abe, Yoshito; Jo, Takaaki; Matsuda, Yusaku; Matsunaga, Chika; Katayama, Tsutomu; Ueda, Tadashi

    2007-06-15

    DnaA forms a homomultimeric complex with the origin of chromosomal replication (oriC) to unwind duplex DNA. The interaction of the DnaA N terminus with the DnaB helicase is crucial for the loading of DnaB onto the unwound region. Here, we determined the DnaA N terminus structure using NMR. This region (residues 1-108) consists of a rigid region (domain I) and a flexible region (domain II). Domain I has an alpha-alpha-beta-beta-alpha-beta motif, similar to that of the K homology (KH) domain, and has weak affinity for oriC single-stranded DNA, consistent with KH domain function. A hydrophobic surface carrying Trp-6 most likely forms the interface for domain I dimerization. Glu-21 is located on the opposite surface of domain I from the Trp-6 site and is crucial for DnaB helicase loading. These findings suggest a model for DnaA homomultimer formation and DnaB helicase loading on oriC.

  12. DNA secondary structure of the released strand stimulates WRN helicase action on forked duplexes without coordinate action of WRN exonuclease

    Energy Technology Data Exchange (ETDEWEB)

    Ahn, Byungchan, E-mail: bbccahn@mail.ulsan.ac.kr [Department of Life Sciences, University of Ulsan, Ulsan (Korea, Republic of); Bohr, Vilhelm A. [Laboratory of Molecular Gerontology, Biomedical Research Center, National Institute on Aging, Baltimore, MD (United States)

    2011-08-12

    Highlights: {yields} In this study, we investigated the effect of a DNA secondary structure on the two WRN activities. {yields} We found that a DNA secondary structure of the displaced strand during unwinding stimulates WRN helicase without coordinate action of WRN exonuclease. {yields} These results imply that WRN helicase and exonuclease activities can act independently. -- Abstract: Werner syndrome (WS) is an autosomal recessive premature aging disorder characterized by aging-related phenotypes and genomic instability. WS is caused by mutations in a gene encoding a nuclear protein, Werner syndrome protein (WRN), a member of the RecQ helicase family, that interestingly possesses both helicase and exonuclease activities. Previous studies have shown that the two activities act in concert on a single substrate. We investigated the effect of a DNA secondary structure on the two WRN activities and found that a DNA secondary structure of the displaced strand during unwinding stimulates WRN helicase without coordinate action of WRN exonuclease. These results imply that WRN helicase and exonuclease activities can act independently, and we propose that the uncoordinated action may be relevant to the in vivo activity of WRN.

  13. Detection of DNA damage induced in vivo by a cross-linking agent with a circular channel crucible oscillating viscometer.

    Science.gov (United States)

    Balbi, C; Abelmoschi, M L; Roner, R; Giaretti, W; Parodi, S; Santi, L

    1985-11-01

    DNA damage induced in vivo by the cross-linking agent mitomycin C (MMC) was investigated with a new oscillating crucible viscometer. Viscosity was measured by lysing rat liver nuclei in an alkaline lysing solution (pH 12.5; 25 degrees C). In control samples the viscosity increased very slowly with time, reaching a plateau only after 10-12 h. The process was accelerated and the maximum viscosity was decreased by alkaline single-stranded breaks arising from methylation and subsequent depurination of DNA in vitro with dimethylsulphate (DMS). MMC, when given alone, had no evident effect on the time needed for reaching plateau viscosity but it induced a small increase in maximum viscosity. When MMC was given in association with DMS, the time of disentanglement remained unchanged (accelerated) but maximum viscosity was increased in a dose dependent way. We conclude that these data clearly confirm that the slow steady increase of the viscosity of control DNA with time reflects mainly the process of unwinding of the two strands. The speed of this process seems to depend only from the number of unwinding points in DNA (breaks).

  14. Convectively driven flow past an infinite moving vertical cylinder with ...

    Indian Academy of Sciences (India)

    , free convective flow over an infinite moving vertical cylinder under combined buoyancy effects of heat and mass transfer with thermal and mass stratifications. Laplace transform technique is adopted for finding solutions for velocity, ...

  15. Steady particulate flows in a horizontal rotating cylinder

    Science.gov (United States)

    Yamane, K.; Nakagawa, M.; Altobelli, S. A.; Tanaka, T.; Tsuji, Y.

    1998-06-01

    Results of discrete element method (DEM) simulation and magnetic resonance imaging (MRI) experiments are compared for monodisperse granular materials flowing in a half-filled horizontal rotating cylinder. Because opacity is not a problem for MRI, a long cylinder with an aspect ratio ˜7 was used and the flow in a thin transverse slice near the center was studied. The particles were mustard seeds and the ratio of cylinder diameter to particle diameter was approximately 50. The parameters compared were dynamic angle of repose, velocity field in a plane perpendicular to the cylinder axis, and velocity fluctuations at rotation rates up to 30 rpm. The agreement between DEM and MRI was good when the friction coefficient and nonsphericity were adjusted in the simulation for the best fit.

  16. Nonlinear Fracture Mechanics and Plasticity of the Split Cylinder Test

    DEFF Research Database (Denmark)

    Olesen, John Forbes; Østergaard, Lennart; Stang, Henrik

    2006-01-01

    The split cylinder testis subjected to an analysis combining nonlinear fracture mechanics and plasticity. The fictitious crack model is applied for the analysis of splitting tensile fracture, and the Mohr-Coulomb yield criterion is adopted for modelling the compressive crushing/sliding failure. Two...... demonstrates the influence of varying geometry or constitutive properties. For a split cylinder test in load control it is shown how the ultimate load is either plasticity dominated or fracture mechanics dominated. The transition between the two modes is related to changes in geometry or constitutive...... properties. This implies that the linear elastic interpretation of the ultimate splitting force in term of the uniaxial tensile strength of the material is only valid for special situations, e.g. for very large cylinders. Furthermore, the numerical analysis suggests that the split cylinder test is not well...

  17. Erosion patterns on a granular bed around a vertical cylinder

    Directory of Open Access Journals (Sweden)

    Lachaussée Florent

    2017-01-01

    Full Text Available We report on two different patterns that can be observed at the bed surface close to a vertical cylinder when submitted to a strong enough steady water flow. The classical scour pattern observed at the cylinder foot and due to the “horseshoe” vortex around occurs at a critical velocity Uc1 below the critical velocity Uc0 for erosion without any cylinder, thus under clear-water conditions. But we observe also another pattern downstream the cylinder which consists of two symmetrical ovoid holes that look like “bunny ears”. This new scour pattern referred as BES can be observed at lower velocities that the horseshoe scour (HSS, above a critical velocity Uc2 < Uc1 , with a timescale formation much higher that the one of HSS.

  18. The optimal spacing for cylinders in crossflow forced convection

    International Nuclear Information System (INIS)

    Bejan, A.

    1995-01-01

    In this note I draw attention to a new fundamental aspect of the heat transfer performance of a bundle of parallel cylinders with crossflow forced convection, namely, the maximization of the thermal contact between the bundle and the fluid, when the volume occupied by the bundle is fixed. In the experiments described by Jubran et al. we have seen empirical evidence that the total heat transfer rate is maximum when the cylinder-to-cylinder spacing S has a certain value. This finding is important because it has been overlooked for decades, while forced convection from cylinders in crossflow grew into one of the most researched topics in heat transfer. 8 refs., 3 figs

  19. Experimental and Computational Investigations of Flow past Spinning Cylinders

    Science.gov (United States)

    Carlucci, Pasquale; Mehmedagic, Igbal; Buckley, Liam; Carlucci, Donald; Thangam, Siva

    2011-11-01

    Experiments are performed in a low speed subsonic wind tunnel to analyze flow past spinning cylinders. The sting-mounted cylinders are oriented such that their axis of rotation is aligned with the mean flow. Data from spinning cylinders with both rear-mounted and fore-mounted stings are presented for a Reynolds numbers of up to 260000 and rotation numbers of up to 1.2 (based on cylinder diameter). Computations are performed using a two-equation turbulence model that is capable of capturing the effects of swirl and curvature. The model performance was validated with benchmark experimental flows and implemented for analyzing the flow configuration used in the experimental study. The results are analyzed and the predictive capability of the model is discussed. Funded in part by U. S. Army, ARDEC.

  20. The Friction of Vehicle Brake Tandem Master Cylinder

    Energy Technology Data Exchange (ETDEWEB)

    Kao, M J [Graduate Institute of Mechanical and Electrical Engineering, National Taipei University of Technology, 1 Sec.3, Chung Hsiao E. Rd. 10608, Taipei, Taiwan (China); Chang, H [Graduate Institute of Mechanical and Electrical Engineering, National Taipei University of Technology, 1 Sec.3, Chung Hsiao E. Rd. 10608, Taipei, Taiwan (China); Tsung, T T [Graduate Institute of Mechanical and Electrical Engineering, National Taipei University of Technology, 1 Sec.3, Chung Hsiao E. Rd. 10608, Taipei, Taiwan (China); Lin, H M [Department of Materials Engineering, Tatung University, Taipei, Taiwan (China)

    2006-10-15

    The behaviour of an elastomeric seal for vehicle brake Tandem master cylinder is measured and analyzed in temperature and brake fluids changed. Working conditions are simulated for different piston rod velocity and cylinder supply pressure, in temperature rising, brakefluid boundary and Nanoaluminum oxide brakefluid oxide brakefluid lubrication. The result shows that Nanoaluminum oxide brakefluid with its ball shape can highly reduce friction coefficient to avoid seal excessive wear and reduce slick slip in brake applications.

  1. The Friction of Vehicle Brake Tandem Master Cylinder

    Science.gov (United States)

    Kao, M. J.; Chang, H.; Tsung, T. T.; Lin, H. M.

    2006-10-01

    The behaviour of an elastomeric seal for vehicle brake Tandem master cylinder is measured and analyzed in temperature and brake fluids changed. Working conditions are simulated for different piston rod velocity and cylinder supply pressure, in temperature rising, brakefluid boundary and Nanoaluminum oxide brakefluid oxide brakefluid lubrication. The result shows that Nanoaluminum oxide brakefluid with its ball shape can highly reduce friction coefficient to avoid seal excessive wear and reduce slick slip in brake applications.

  2. Robust Cylinder Fitting in Three-Dimensional Point Cloud Data

    Science.gov (United States)

    Nurunnabi, A.; Sadahiro, Y.; Lindenbergh, R.

    2017-05-01

    This paper investigates the problems of cylinder fitting in laser scanning three-dimensional Point Cloud Data (PCD). Most existing methods require full cylinder data, do not study the presence of outliers, and are not statistically robust. But especially mobile laser scanning often has incomplete data, as street poles for example are only scanned from the road. Moreover, existence of outliers is common. Outliers may occur as random or systematic errors, and may be scattered and/or clustered. In this paper, we present a statistically robust cylinder fitting algorithm for PCD that combines Robust Principal Component Analysis (RPCA) with robust regression. Robust principal components as obtained by RPCA allow estimating cylinder directions more accurately, and an existing efficient circle fitting algorithm following robust regression principles, properly fit cylinder. We demonstrate the performance of the proposed method on artificial and real PCD. Results show that the proposed method provides more accurate and robust results: (i) in the presence of noise and high percentage of outliers, (ii) for incomplete as well as complete data, (iii) for small and large number of points, and (iv) for different sizes of radius. On 1000 simulated quarter cylinders of 1m radius with 10% outliers a PCA based method fit cylinders with a radius of on average 3.63 meter (m); the proposed method on the other hand fit cylinders of on average 1.02 m radius. The algorithm has potential in applications such as fitting cylindrical (e.g., light and traffic) poles, diameter at breast height estimation for trees, and building and bridge information modelling.

  3. Cylinder expansion test and gas gun experiment comparison

    Energy Technology Data Exchange (ETDEWEB)

    Harrier, Danielle [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-06-30

    This is a summer internship presentation by the Hydro Working Group at Los Alamos National Laboratory (LANL) and goes into detail about their cylinder expansion test and gas gun experiment comparison. Specifically, the gas gun experiment is detailed along with applications, the cylinder expansion test is detailed along with applications, there is a comparison of the methods with pros and cons and limitations listed, the summer project is detailed, and future work is talked about.

  4. Radiation dose rates from UF{sub 6} cylinders

    Energy Technology Data Exchange (ETDEWEB)

    Friend, P.J. [Urenco, Capenhurst (United Kingdom)

    1991-12-31

    This paper describes the results of many studies, both theoretical and experimental, which have been carried out by Urenco over the last 15 years into radiation dose rates from uranium hexafluoride (UF{sub 6}) cylinders. The contents of the cylinder, its history, and the geometry all affect the radiation dose rate. These factors are all examined in detail. Actual and predicted dose rates are compared with levels permitted by IAEA transport regulations.

  5. Longitudinal Weld Land Buckling in Compression-Loaded Orthogrid Cylinders

    Science.gov (United States)

    Thornburgh, Robert P.; Hilburger, Mark W.

    2010-01-01

    Large stiffened cylinders used in launch vehicles (LV), such as the Space Shuttle External Tank, are manufactured by welding multiple curved panel sections into complete cylinders. The effects of the axial weld lands between the panel sections on the buckling load were studied, along with the interaction between the acreage stiffener arrangement and the weld land geometry. This document contains the results of the studies.

  6. MATHEMATICAL METHODS TO DETERMINE THE INTERSECTION CURVES OF THE CYLINDERS

    Directory of Open Access Journals (Sweden)

    POPA Carmen

    2010-07-01

    Full Text Available The aim of this paper is to establish the intersection curves between cylinders, by using the Mathematica program. This thing can be obtained by introducing the curves equations, which are inferred, in Mathematica program. This paper take into discussion three right cylinders and another inclined to 45 degrees. The intersection curves can also be obtained by using the classical methods of the descriptive geometry.

  7. Relaxation of Thick-Walled Cylinders and Spheres

    DEFF Research Database (Denmark)

    Saabye Ottosen, N.

    1982-01-01

    Using the nonlinear creep law proposed by Soderberg, (1936) closed-form solutions are derived for the relaxation of incompressible thick-walled spheres and cylinders in plane strain. These solutions involve series expressions which, however, converge very quickly. By simply ignoring these series...... expressions, extremely simple approximate solutions are obtained. Despite their simplicity these approximations possess an accuracy that is superior to approximations currently in use. Finally, several physical aspects related to the relaxation of cylinders and spheres are discussed...

  8. ROBUST CYLINDER FITTING IN THREE-DIMENSIONAL POINT CLOUD DATA

    Directory of Open Access Journals (Sweden)

    A. Nurunnabi

    2017-05-01

    Full Text Available This paper investigates the problems of cylinder fitting in laser scanning three-dimensional Point Cloud Data (PCD. Most existing methods require full cylinder data, do not study the presence of outliers, and are not statistically robust. But especially mobile laser scanning often has incomplete data, as street poles for example are only scanned from the road. Moreover, existence of outliers is common. Outliers may occur as random or systematic errors, and may be scattered and/or clustered. In this paper, we present a statistically robust cylinder fitting algorithm for PCD that combines Robust Principal Component Analysis (RPCA with robust regression. Robust principal components as obtained by RPCA allow estimating cylinder directions more accurately, and an existing efficient circle fitting algorithm following robust regression principles, properly fit cylinder. We demonstrate the performance of the proposed method on artificial and real PCD. Results show that the proposed method provides more accurate and robust results: (i in the presence of noise and high percentage of outliers, (ii for incomplete as well as complete data, (iii for small and large number of points, and (iv for different sizes of radius. On 1000 simulated quarter cylinders of 1m radius with 10% outliers a PCA based method fit cylinders with a radius of on average 3.63 meter (m; the proposed method on the other hand fit cylinders of on average 1.02 m radius. The algorithm has potential in applications such as fitting cylindrical (e.g., light and traffic poles, diameter at breast height estimation for trees, and building and bridge information modelling.

  9. Magnus effect on laminar flow around a rotating cylinder

    International Nuclear Information System (INIS)

    Amarante, J.C.A.

    1989-01-01

    The laminar flow around a rotating cylinder is studied, through the numerical solution of the full Navier-Stokes equations, for Reynolds number, based on cylinder radius, varying between 0.5 and 25 and for non-dimensional tangential velocities of the body surface between zero and 8. The Taylor and Hughes method is employed in the theoretical investigation. The Magnus lift coefficient and the drag coefficient are obtained and the presure and vorticity distribution are calculated. (author)

  10. Optimization of In-Cylinder Pressure Filter for Engine Research

    Science.gov (United States)

    2017-06-01

    ARL-TR-8034 ● JUN 2017 US Army Research Laboratory Optimization of In-Cylinder Pressure Filter for Engine Research by Kenneth...Destroy this report when it is no longer needed. Do not return it to the originator. ARL-TR-8034 ● JUN 2017 US Army Research ...Laboratory Optimization of In-Cylinder Pressure Filter for Engine Research by Kenneth S Kim, Michael T Szedlmayer, Kurt M Kruger, and Chol-Bum M

  11. Mathematic modelling of circular cylinder deformation under inner grouwth

    Directory of Open Access Journals (Sweden)

    A. V. Siasiev

    2009-09-01

    Full Text Available A task on the intensive deformed state (IDS of a viscoelastic declivous cylinder, which is grown under the action of inner pressure, is considered. The process of continuous increase takes a place on an internal radius so, that a radius and pressure change on set to the given law. The special case of linear law of creeping is considered, and also numeral results are presented as the graphs of temporal dependence of tensions and moving for different points of cylinder.

  12. Criticality concerns in cleaning large uranium hexafluoride cylinders

    International Nuclear Information System (INIS)

    Sheaffer, M.K.; Keeton, S.C.; Lutz, H.F.

    1995-06-01

    Cleaning large cylinders used to transport low-enriched uranium hexafluoride (UF 6 ) presents several challenges to nuclear criticality safety. This paper presents a brief overview of the cleaning process, the criticality controls typically employed and their bases. Potential shortfalls in implementing these controls are highlighted, and a simple example to illustrate the difficulties in complying with the Double Contingency Principle is discussed. Finally, a summary of recommended criticality controls for large cylinder cleaning operations is presented

  13. A characteristic analysis of the fluidic muscle cylinder

    Science.gov (United States)

    Kim, Dong-Soo; Bae, Sang-Kyu; Hong, Sung-In

    2005-12-01

    The fluidic muscle cylinder consists of an air bellows tube, flanges and lock nuts. It's features are softness of material and motion, simplicity of structure, low production cost and high power efficiency. Recently, unlikely the pneumatic cylinder, the fluidic muscle cylinder without air leakage, stick slip, friction, and seal was developed as a new concept actuator. It has the characteristics such as light weight, low price, high response, durable design, long life, high power, high contraction, which is innovative product fulfilling RT(Robot Technology) which is one of the nation-leading next generation strategy technologies 6T as well as cleanness technology. The application fields of the fluidic muscle cylinder are so various like fatigue tester, brake, accelerator, high technology testing device such as driving simulator, precise position, velocity, intelligent servo actuator under special environment such as load controlling system, and intelligent robot. In this study, we carried out the finite element modeling and analysis about the main design variables such as contraction ration and force, diameter increment of fluidic muscle cylinder. On the basis of finite element analysis, the prototype of fluidic muscle cylinder was manufactured and tested. Finally, we compared the results between the test and the finite element analysis.

  14. Passively Enhancing Convection Heat Transfer Around Cylinder Using Shrouds

    Science.gov (United States)

    Samaha, Mohamed A.; Kahwaji, Ghalib Y.

    2017-11-01

    Natural convection heat transfer around a horizontal cylinder has received considerable attention through decades since it has been used in several viable applications. However, investigations into passively enhancement of the free convective cooling using external walls and chimney effect are lacking. In this work, a numerical simulation to study natural convection from a horizontal cylinder configured with semicircular shrouds with an expended chimney is employed. The fluid flow and convective heat transfer around the cylinder are modeled. The bare cylinder is also simulated for comparison. The present study are aimed at improving our understanding of the parameters advancing the free convective cooling of the cylinder implemented with the shrouds configuration. For validation, the present results for the bare tube are compared with data reported in the literature. The numerical simulations indicate that applying the shrouds configuration with extended chimney to a tube promotes the convection heat transfer from the cylinder. Such a method is less expensive and simpler in design than other configurations (e.g. utilizing extended surfaces, fins), making the technology more practical for industrial productions, especially for cooling systems. Dubai Silicon Oasis Authority (DSOA) Grants.

  15. Universal SCFs and optimal chamfering in cross-bored cylinders

    International Nuclear Information System (INIS)

    Kihiu, J.M.; Rading, G.O.; Mutuli, S.M.

    2007-01-01

    A three-dimensional finite element computer program was developed to establish the stress distributions and stress concentration factors (SCFs) in chamfered cross-bored cylinders under internal pressure. The displacement formulation using eight noded brick and four noded tetrahedron isoparametric elements was used. The Frontal solution technique was used due to limited computing facilities. For several thickness ratios and cross bore to main bore radius ratios, the variation of SCF with chamfer angle for various chamfer length (clr) ratios was investigated. In each case, a universal SCF value corresponding to a unique value of chamfer angle was established. For most clr and chamfer angle combinations, the SCF was higher than that of a plain cross-bored cylinder. However, for some combinations, the SCF curve had an optimum value lower than that of a plain cross-bored cylinder. In optimal chamfered cylinders with thickness ratio between 2.25 and 3, the SCF was found to increase with decrease of thickness ratio. Where thickness ratio was between 1.25 and 2, a cross bore to main bore radius ratio of 0.075 was found to be a geometrical constant with a corresponding SCF of 2.65. Thick cylinders were found to be more suited to chamfering than thin cylinders. The resulting data in this work provides a useful and quick design tool

  16. Universal SCFs and optimal chamfering in cross-bored cylinders

    Energy Technology Data Exchange (ETDEWEB)

    Kihiu, J.M. [Department of Mechanical Engineering, Jomo Kenyatta University of Agriculture and Technology, PO Box 62000, 00200 Nairobi (Kenya); Rading, G.O. [University of Nairobi (Kenya); Mutuli, S.M. [University of Nairobi (Kenya)

    2007-06-15

    A three-dimensional finite element computer program was developed to establish the stress distributions and stress concentration factors (SCFs) in chamfered cross-bored cylinders under internal pressure. The displacement formulation using eight noded brick and four noded tetrahedron isoparametric elements was used. The Frontal solution technique was used due to limited computing facilities. For several thickness ratios and cross bore to main bore radius ratios, the variation of SCF with chamfer angle for various chamfer length (clr) ratios was investigated. In each case, a universal SCF value corresponding to a unique value of chamfer angle was established. For most clr and chamfer angle combinations, the SCF was higher than that of a plain cross-bored cylinder. However, for some combinations, the SCF curve had an optimum value lower than that of a plain cross-bored cylinder. In optimal chamfered cylinders with thickness ratio between 2.25 and 3, the SCF was found to increase with decrease of thickness ratio. Where thickness ratio was between 1.25 and 2, a cross bore to main bore radius ratio of 0.075 was found to be a geometrical constant with a corresponding SCF of 2.65. Thick cylinders were found to be more suited to chamfering than thin cylinders. The resulting data in this work provides a useful and quick design tool.

  17. Flow induced vibrations in arrays of irregularly spaced cylinders

    Science.gov (United States)

    Taub, Gordon; Michelin, Sébastien

    2014-11-01

    Historically the main industrial applications of cylinder arrays in cross flows favored regular arrangements of cylinders. For this reason, most past studies of Flow Induced Vibrations (FIV) in large cylinder arrays have focused on such arrangements. Recently there has been some interest in generating renewable energy using FIV of bluff bodies. In such applications it will likely be beneficial to enhance, rather than suppress FIV. It is not known a priori if regular or irregularly spaced arrays are most adequate for this type of application. In this study, wind tunnel experiments were conducted on one regularly spaced array and four different irregularly spaced arrays of cylinders in a cross flow. Each arrangement of cylinders was examined under eight different orientations to a cross flow ranging between 10 m/s and 17 m/s. The average amplitude of vibration of the cylinders was found to highly depend on arrangement and orientation. The typical amplitude of vibration of the rods in the irregular arrangements were found to be an order of magnitude larger than that of the regular array. A simple model was proposed in order to predict if a given arrangement was likely to produce large oscillations, and the validity of the model was examined. This research was supported by a Marie Curie International Reintegration Grant within the 7th European Community Framework Program (Grant PIRG08-GA-2010-276762).

  18. 76 FR 71124 - Safety Advisory: Unauthorized Marking of Compressed Gas Cylinders

    Science.gov (United States)

    2011-11-16

    .... PHMSA-2011-0241, (Notice No. 11-10)] Safety Advisory: Unauthorized Marking of Compressed Gas Cylinders... Notice. SUMMARY: An undetermined number of high pressure DOT specification cylinders were improperly... these cylinders, a person must verify that the cylinder has been properly requalified by an authorized...

  19. 77 FR 1975 - Safety Advisory: Unauthorized Marking of Compressed Gas Cylinders

    Science.gov (United States)

    2012-01-12

    .... PHMSA-2011-0328; Notice No. 11-15] Safety Advisory: Unauthorized Marking of Compressed Gas Cylinders... Jackson Plaza, Ann Arbor, MI improperly requalified and marked high pressure compressed gas cylinders... DOT specification cylinders after its authority to requalifiy high pressure cylinders expired on...

  20. 76 FR 33023 - Safety Advisory; Unauthorized Marking of Compressed Gas Cylinders

    Science.gov (United States)

    2011-06-07

    .... PHMSA-2011-0122, Notice No. 11-4] Safety Advisory; Unauthorized Marking of Compressed Gas Cylinders... of certain (aluminum) cylinders were improperly marked and represented as DOT specification 3AL cylinders. The cylinders were neither marked nor certified by an authorized independent inspection agency...

  1. 30 CFR 75.1106-4 - Use of liquefied and nonliquefied compressed gas cylinders; general requirements.

    Science.gov (United States)

    2010-07-01

    ... gas cylinders; general requirements. 75.1106-4 Section 75.1106-4 Mineral Resources MINE SAFETY AND...-UNDERGROUND COAL MINES Fire Protection § 75.1106-4 Use of liquefied and nonliquefied compressed gas cylinders... compressed gas unit, consisting of one oxygen cylinder and one additional gas cylinder, shall be used to...

  2. 78 FR 16045 - Safety Advisory: Unauthorized Marking of Compressed Gas Cylinders

    Science.gov (United States)

    2013-03-13

    .... PHMSA-2013-0019; Notice No. 13-03] Safety Advisory: Unauthorized Marking of Compressed Gas Cylinders... specification cylinders. Cylinders described in this safety advisory that are filled with an atmospheric gas... of certain high pressure DOT specification cylinders marked with a requalification identification...

  3. Compression Tests on Circular Cylinders Stiffened Longitudinally by Closely Spaced Z-Section Stringers

    Science.gov (United States)

    Peterson, James P.; Dow, Marvin B.

    1959-01-01

    Six circular cylinders stiffened longitudinally by closely spaced Z-section stringers were loaded to failure in compression. The results obtained are presented and compared with available theoretical results for the buckling of orthotropic cylinders. The results indicate that the large disparity that exists between theory and experiment for unstiffened compression cylinders may be significantly smaller for stiffened cylinders.

  4. Modelling and numerical simulation of vortex induced vibrations of single cylinder or cylinder arrays

    International Nuclear Information System (INIS)

    Jus, Y.

    2011-01-01

    This research thesis fits into the frame of researches achieved in the nuclear field in order to optimize the predictive abilities of sizing models of nuclear plant components. It more precisely addresses the modelling of the action exerted by the flowing fluid and the induced feedback by the structure dynamics. The objective is herein to investigate the interaction between the turbulence at the wall vicinity and the effects of non-conservative and potentially destabilizing unsteady coupling. The peculiar case of a single cylinder in infinite environment, and submitted to a transverse flow, is studied statically and then dynamically. The influence of flow regimes on dynamic response is characterized, and the quantification of fluid-structure interaction energy is assessed. The author then addresses the case of an array of cylinders, and highlights the contribution of three-dimensional macro-simulations for the analysis of flow-induced structure vibrations in subcritical regime within a High Performance Calculation (HPC) framework, and the interest of a CFD/CSM (computational fluid dynamics/computational structure mechanics) coupling in the case of turbulent flows in an industrial environment

  5. Mechanism of drag reduction for circular cylinders with patterned surface

    International Nuclear Information System (INIS)

    Butt, U.; Jehring, L.; Egbers, C.

    2014-01-01

    Highlights: • Reduced drag of patterned cylinders over a wide range of Re numbers. • Hexagonal patterns cannot be characterized as roughness structures. • Hexagonal bumps affect the flow like spherical dimples of smaller k/d ratio do. • Main separation is delayed caused by a partial separation. • Angle of a separation line is not constant over the length of cylinder. -- Abstract: In this paper, the flow over cylinders with a patterned surface (k/d = 1.98 × 10 −2 ) is investigated in a subsonic wind tunnel over Reynolds numbers ranging from 3.14 × 10 4 to 2.77 × 10 5 by measuring drag, flow visualization and measuring velocity profiles above the surface of the cylinders, to observe the effect of hexagonal patterns on the flow of air. These patterns can also be referred as hexagonal dimples or bumps depending on their configuration. The investigations revealed that a patterned cylinder with patterns pressed outwards has a drag coefficient of about 0.65 times of a smooth one. Flow visualization techniques including surface oil-film technique and velocity profile measurement were employed to elucidate this effect, and hence present the mechanism of drag reduction. The measurement of velocity profiles using hot-wire anemometry above the surface reveal that a hexagonal bump cause local separation generating large turbulence intensity along the separating shear layer. Due to this increased turbulence, the flow reattaches to the surface with higher momentum and become able to withstand the pressure gradient delaying the main separation significantly. Besides that, the separation does not appear to occur in a straight line along the length of the cylinder as in case of most passive drag control methods, but follow exactly the hexagonal patterns forming a wave with its crest at 115° and trough at 110°, in contrast to the laminar separation line at 85° for a smooth cylinder

  6. Treatment of anxiety in patients with coronary heart disease: Rationale and design of the UNderstanding the benefits of exercise and escitalopram in anxious patients WIth coroNary heart Disease (UNWIND) randomized clinical trial.

    Science.gov (United States)

    Blumenthal, James A; Feger, Bryan J; Smith, Patrick J; Watkins, Lana L; Jiang, Wei; Davidson, Jonathan; Hoffman, Benson M; Ashworth, Megan; Mabe, Stephanie K; Babyak, Michael A; Kraus, William E; Hinderliter, Alan; Sherwood, Andrew

    2016-06-01

    Anxiety is highly prevalent among patients with coronary heart disease (CHD), and there is growing evidence that high levels of anxiety are associated with worse prognosis. However, few studies have evaluated the efficacy of treating anxiety in CHD patients for reducing symptoms and improving clinical outcomes. Exercise and selective serotonin reuptake inhibitors have been shown to be effective in treating patients with depression, but have not been studied in cardiac patients with high anxiety. The UNWIND trial is a randomized clinical trial of patients with CHD who are at increased risk for adverse events because of comorbid anxiety. One hundred fifty participants with CHD and elevated anxiety symptoms and/or with a diagnosed anxiety disorder will be randomly assigned to 12 weeks of aerobic exercise (3×/wk, 35 min, 70%-85% VO2peak), escitalopram (5-20 mg qd), or placebo. Before and after 12 weeks of treatment, participants will undergo assessments of anxiety symptoms and CHD biomarkers of risk, including measures of inflammation, lipids, hemoglobin A1c, heart rate variability, and vascular endothelial function. Primary outcomes include post-intervention effects on symptoms of anxiety and CHD biomarkers. Secondary outcomes include clinical outcomes (cardiovascular hospitalizations and all-cause death) and measures of quality of life. The UNWIND trial (ClinicalTrials.gov NCT02516332) will evaluate the efficacy of aerobic exercise and escitalopram for improving anxiety symptoms and reducing risk for adverse clinical events in anxious CHD patients. Copyright © 2016 Elsevier Inc. All rights reserved.

  7. Conversion of low BMEP 4-cylinder to high BMEP 2-cylinder large bore natural gas engine

    Science.gov (United States)

    Ladd, John

    There are more than 6,000 integral compressor engines in use on US natural gas pipelines, operating 24 hours a day, 365 days a year. Many of these engines have operated continuously for more than 50 years, with little to no modifications. Due to recent emission regulations at the local, state and federal levels much of the aging infrastructure requires retrofit technology to remain within compliance. The Engines and Energy Conversion Laboratory was founded to test these retrofit technologies on its large bore engine testbed (LBET). The LBET is a low brake mean effective pressure (BMEP) Cooper Bessemer GMVTF-4. Newer GMV models, constructed in 1980's, utilize turbocharging to increase the output power, achieving BMEP's nearly double that of the LBET. To expand the lab's testing capability and to reduce the LBET's running cost: material testing, in-depth modeling, and on engine testing was completed to evaluate the feasibility of uprating the LBET to a high BMEP two cylinder engine. Due to the LBET's age, the crankcase material properties were not known. Material samples were removed from engine to conduct an in-depth material analysis. It was found that the crankcase was cast out of a specific grade of gray iron, class 25 meehanite. A complete three dimensional model of the LBET's crankcase and power cylinders was created. Using historical engine data, the force inputs were created for a finite element analysis model of the LBET, to determine the regions of high stress. The areas of high stress were instrumented with strain gauges to iterate and validate the model's findings. Several test cases were run at the high and intermediate BMEP engine conditions. The model found, at high BMEP conditions the LBET would operate at the fatigue limit of the class 25 meehanite, operating with no factor of safety but the intermediate case were deemed acceptable.

  8. AFM tip-sample convolution effects for cylinder protrusions

    Science.gov (United States)

    Shen, Jian; Zhang, Dan; Zhang, Fei-Hu; Gan, Yang

    2017-11-01

    A thorough understanding about the AFM tip geometry dependent artifacts and tip-sample convolution effect is essential for reliable AFM topographic characterization and dimensional metrology. Using rigid sapphire cylinder protrusions (diameter: 2.25 μm, height: 575 nm) as the model system, a systematic and quantitative study about the imaging artifacts of four types of tips-two different pyramidal tips, one tetrahedral tip and one super sharp whisker tip-is carried out through comparing tip geometry dependent variations in AFM topography of cylinders and constructing the rigid tip-cylinder convolution models. We found that the imaging artifacts and the tip-sample convolution effect are critically related to the actual inclination of the working cantilever, the tip geometry, and the obstructive contacts between the working tip's planes/edges and the cylinder. Artifact-free images can only be obtained provided that all planes and edges of the working tip are steeper than the cylinder sidewalls. The findings reported here will contribute to reliable AFM characterization of surface features of micron or hundreds of nanometers in height that are frequently met in semiconductor, biology and materials fields.

  9. Spatial damping of propagating sausage waves in coronal cylinders

    Science.gov (United States)

    Guo, Ming-Zhe; Chen, Shao-Xia; Li, Bo; Xia, Li-Dong; Yu, Hui

    2015-09-01

    Context. Sausage modes are important in coronal seismology. Spatially damped propagating sausage waves were recently observed in the solar atmosphere. Aims: We examine how wave leakage influences the spatial damping of sausage waves propagating along coronal structures modeled by a cylindrical density enhancement embedded in a uniform magnetic field. Methods: Working in the framework of cold magnetohydrodynamics, we solve the dispersion relation (DR) governing sausage waves for complex-valued, longitudinal wavenumber k at given real angular frequencies ω. For validation purposes, we also provide analytical approximations to the DR in the low-frequency limit and in the vicinity of ωc, the critical angular frequency separating trapped from leaky waves. Results: In contrast to the standing case, propagating sausage waves are allowed for ω much lower than ωc. However, while able to direct their energy upward, these low-frequency waves are subject to substantial spatial attenuation. The spatial damping length shows little dependence on the density contrast between the cylinder and its surroundings, and depends only weakly on frequency. This spatial damping length is of the order of the cylinder radius for ω ≲ 1.5vAi/a, where a and vAi are the cylinder radius and the Alfvén speed in the cylinder, respectively. Conclusions: If a coronal cylinder is perturbed by symmetric boundary drivers (e.g., granular motions) with a broadband spectrum, wave leakage efficiently filters out the low-frequency components.

  10. Hydrogen Bubbles as a Visualization Tool for Cylinder Shedding

    Science.gov (United States)

    Sigurdson, Lorenz; Gilbert, Stuart

    2004-11-01

    We examine the behavior of hydrogen bubbles formed by electrolysis of water on a 2.54 mm cylindrical electrode in a water tunnel. The Reynolds Number based on cylinder diameter varies from 400 to 1100, and tunnel velocities range from 17 to 50 cm/s. At the lowest velocity buoyancy is a strong effect which inhibits accurate flow tracking by the bubbles. This effect largely disappears by 25 cm/s. As the tunnel velocity increases, bubble size decreases, reflected light for photography is reduced, and bubbles begin to track the von Karman vortex street vortex cores near the cylinder. The vortex cores have a sufficiently low pressure to capture the bubbles. Vortex street wavelength is seen to discretely increase as vortices proceed downstream. The location of this scale-change becomes nearer the cylinder as Re increases. Voids of bubbles occur in continuous linear downstream segments originating near the cylinder. They seem to be due to vortex modification in the wake similar to what other cylinder shedding researchers have found.

  11. Performance of a Horizontal Triple Cylinder Type Pulping Machine

    Directory of Open Access Journals (Sweden)

    Sukrisno Widyotomo

    2011-05-01

    Full Text Available Pulping is one important step in wet coffee processing method. Pulping process usually uses a machine which constructed by wood or metal materials. A horizontal single cylinder type of fresh coffee cherries pulping machine is the most popular machine in coffee processing. One of the weaknesses of a horizontal single cylinder type of fresh coffee cherries pulping machine is higher in broken beans. Broken bean is one of mayor aspects in defect system that contribute to low quality. Indonesian Coffee and Cocoa Research Institute has designed and tested a horizontal double cylinder type of fresh coffee cherries pulping machine which resulted in 12.6—21.4% of broken beans. To reduce percentage of broken beans, Indonesian Coffee and Cocoa Research Institute has developed and tested a horizontal triple cylinder type of fresh coffee cherries pulping machine. Material tested was fresh mature Robusta coffee cherries, 60—65% (wet basis moisture content; has classified on 3 levels i.e. unsorted, small and medium, and clean from metal and foreign materials. The result showed that the machine produced 6,340 kg/h in optimal capacity for operational conditions, 1400 rpm rotor rotation speed for unsorted coffee cherries with composition 55.5% whole parchment coffee, 3.66% broken beans, and 1% beans in wet skin.Key words : coffee, pulp, pulper, cylinder, quality.

  12. Composite reinforced metallic cylinder for high-speed rotation

    Science.gov (United States)

    Pradhan, Sahadev, , Dr.

    The objective of the present study is to design and development of the composite reinforced thin metallic cylinder to increase the peripheral speed significantly and thereby? improve the separation performance in a centrifugal gas separation processes through? proper optimization of the internal parameters. According to Dirac equation (Cohen? (1951)), the maximum separative work for a centrifugal gas separation process increases? with 4th power of the peripheral speed. Therefore, it has been intended to reinforce the? metallic cylinder with composites (carbon fibers: T-700 and T- 1000 grade with suitable? epoxy resin) to increase the stiffness and hoop stress so that the peripheral speed can? be increased significantly, and thereby enhance the separative output. Here, we have developed the mathematical model to investigate the elastic stresses of? a laminated cylinder subjected to mechanical, thermal and thermo-mechanical loading.? A detailed analysis is carried out to underline the basic hypothesis of each formulation.? Further, we evaluate the steady state creep response of the rotating cylinder and analyze? the stresses and strain rates in the cylinder. Dr. Sahadev Pradhan Department of Chemical Engineering, Indian Institute of Science, Bangalore-560 012, India.

  13. Composite reinforced metallic cylinder for? high-speed rotation

    Science.gov (United States)

    Pradhan, Sahadev, , Dr.

    2017-01-01

    The objective of the present study is to design and development of the composite reinforced thin metallic cylinder to increase the peripheral speed significantly and thereby? improve the separation performance in a centrifugal gas separation processes through? proper optimization of the internal parameters. According to Dirac equation (Cohen? (1951)), the maximum separative work for a centrifugal gas separation process increase? with 4th power of the peripheral speed. Therefore, it has been intended to reinforce the? metallic cylinder with composites (carbon fibers: T-700 and T- 1000 grade with suitable? epoxy resin) to increase the stiffness and hoop stress so that the peripheral speed can? be increased significantly, and thereby enhance the separative output. Here, we have developed the mathematical model to investigate the elastic stresses of? a laminated cylinder subjected to mechanical, thermal and thermo-mechanical loading? A detailed analysis is carried out to underline the basic hypothesis of each formulation? Further, we evaluate the steady state creep response of the rotating cylinder and analyze? the stresses and strain rates in the cylinder.

  14. Composite reinforced metallic cylinder for high speed rotation

    Science.gov (United States)

    Pradhan, Sahadev

    2017-11-01

    The objective of the present study is to design and development of the composite reinforced thin metallic cylinder to increase the peripheral speed significantly and thereby improve the separation performance in a centrifugal gas separation processes through proper optimization of the internal parameters. According to Dirac equation (Cohen (1951)), the maximum separative work for a centrifugal gas separation process increase with 4th power of the peripheral speed. Therefore, it has been intended to reinforce the metallic cylinder with composites (carbon fibers: T-700 and T- 1000 grade with suitable epoxy resin) to increase the stiffness and hoop stress so that the peripheral speed can be increased significantly, and thereby enhance the separative output. Here, we have developed the mathematical model to investigate the elastic stresses of a laminated cylinder subjected to mechanical, thermal and thermo-mechanical loading. A detailed analysis is carried out to underline the basic hypothesis of each formulation. Further, we evaluate the steady state creep response of the rotating cylinder and analyze the stresses and strain rates in the cylinder.

  15. Experimental study on flow past a rotationally oscillating cylinder

    Science.gov (United States)

    Gao, Yang-yang; Yin, Chang-shan; Yang, Kang; Zhao, Xi-zeng; Tan, Soon Keat

    2017-08-01

    A series of experiments was carried out to study the flow behaviour behind a rotationally oscillating cylinder at a low Reynolds number (Re=300) placed in a recirculation water channel. A stepper motor was used to rotate the cylinder clockwise- and- counterclockwise about its longitudinal axis at selected frequencies. The particle image velocimetry (PIV) technique was used to capture the flow field behind a rotationally oscillating cylinder. Instantaneous and timeaveraged flow fields such as the vorticity contours, streamline topologies and velocity distributions were analyzed. The effects of four rotation angle and frequency ratios F r ( F r= f n/ f v, the ratio of the forcing frequency f n to the natural vortex shedding frequency f v) on the wake in the lee of a rotationally oscillating cylinder were also examined. The significant wake modification was observed when the cylinder undergoes clockwise-and-counterclockwise motion with amplitude of π, especially in the range of 0.6≤ F r≤1.0.

  16. Atilt rolling movement of a gas cylinder: a case study.

    Science.gov (United States)

    Chen, Yi-Lang; Chiang, Hsi-Ting

    2014-01-01

    We analyzed a case study for rolling gas cylinders for a large technology company in Taiwan. Four experienced employees participated in this study. The cylinder transporting postures of participants were photographed for Rapid Upper Limb Assessment (RULA) and a goniometer was used for data gathering. The results showed that for atilt rolling movement and positioning of gas cylinders, the postures assessed by RULA all exceeded Action Level 3. The repetitive activity for each wrist was as high as 1 time/s. The radial deviation for each wrist and the dorsiflexion on the right wrist nearly reached the maximum range of motion. This suggested that the tasks might potentially cause injury to the upper limbs (particularly the wrists) and require action "investigation and changes are required soon", as suggested by RULA. The results of this case analysis can be preliminarily used as a reference for related operation evaluation and improvement.

  17. Hoop Tensile Properties of Ceramic Matrix Composite Cylinders

    Science.gov (United States)

    Verrilli, Michael J.; DiCarlo, James A.; Yun, HeeMan; Barnett, Terry

    2004-01-01

    Tensile stress-strain properties in the hoop direction were obtained for 100-mm diameter SiC/SiC ceramic matrix composite cylinders using ring specimens machined form the cylinder ends. The cylinders were fabricated from 2D balanced SiC fabric with several material variants, including wall thickness (6,8, and 12 plies), SiC fiber type (Sylramic, Sylramic-iBN, Hi-Nicalon, and Hi-Nicalon S), fiber sizing type, and matrix type (full CVI SiC, and partial CVI SiC plus slurry cast + melt-infiltrated SiC-Si). Fiber ply splices existed in all the hoops. Tensile hoop measurements are made at room temperature and 1200 C using hydrostatic ring test facilities. The failure mode of the hoops, determined through microstructural examination, is presented. The hoop properties are compared with in-plane data measured on flat panels using same material variants, but containing no splices.

  18. Mathematical modeling of a hydrophilic cylinder floating on water.

    Science.gov (United States)

    Mao, Zai-Sha; Yang, Chao; Chen, Jiayong

    2012-07-01

    In this paper, a hydrostatic model of the surface profile anchored to the upper edge of a vertical cylinder is proposed to explain why coins can float on water surface. The sharp edge of a cylinder is thus modeled as a round smooth surface on which the contact line may be anchored at a position according to the weight of the cylinder. The mathematical model of the surface profile is established based on the hydrostatics and a third order ordinary differential equation is resulted. Numerical solution of the model demonstrates under practical conditions the existence of the surface profiles that provide reasonable uplifting force at the contact line so that the force is available for floating coins on water surface. The proposed model explains the obviously enlarged apparent contact angle and the edge effect in the literature. The numerical simulation is found in very good agreement with the experimental data in the literature. Copyright © 2012 Elsevier Inc. All rights reserved.

  19. Analysis of residual stresses in a long hollow cylinder

    International Nuclear Information System (INIS)

    Tokovyy, Yuriy V.; Ma, Chien-Ching

    2011-01-01

    This paper presents an analytical method for solving the axisymmetric stress problem for a long hollow cylinder subjected to locally-distributed residual (incompatible) strains. This method is based on direct integration of the equilibrium and compatibility equations, which thereby have been reduced to the set of two governing equations for two key functions with corresponding boundary and integral conditions. The governing equations were solved by making use of the Fourier integral transformation. Application of the method is illustrated with an analysis of the welding residual stresses in a butt-welded thick-walled pipe. - Highlights: → A solution to the axisymmetric stress problem for a hollow cylinder is constructed. → The cylinder is subjected to a field of locally-distributed residual strains. → The method is based on direct integration of the equilibrium equations. → An application of our solution to analysis of welding residual stresses is considered.

  20. Filament winding cylinders. II - Validation of the process model

    Science.gov (United States)

    Calius, Emilio P.; Lee, Soo-Yong; Springer, George S.

    1990-01-01

    Analytical and experimental studies were performed to validate the model developed by Lee and Springer for simulating the manufacturing process of filament wound composite cylinders. First, results calculated by the Lee-Springer model were compared to results of the Calius-Springer thin cylinder model. Second, temperatures and strains calculated by the Lee-Springer model were compared to data. The data used in these comparisons were generated during the course of this investigation with cylinders made of Hercules IM-6G/HBRF-55 and Fiberite T-300/976 graphite-epoxy tows. Good agreement was found between the calculated and measured stresses and strains, indicating that the model is a useful representation of the winding and curing processes.

  1. Flow past an axially aligned spinning cylinder: Experimental Study

    Science.gov (United States)

    Carlucci, Pasquale; Buckley, Liam; Mehmedagic, Igbal; Carlucci, Donald; Thangam, Siva

    2017-11-01

    Experimental investigation of flow past a spinning cylinder is presented in the context of its application and relevance to flow past projectiles. A subsonic wind tunnel is used to perform experiments on the flow past a spinning cylinder that is mounted on a forward sting and oriented such that its axis of rotation is aligned with the mean flow. The experiments cover a Reynolds number of range of up to 45000 and rotation numbers of up to 2 (based on cylinder diameter). Time-averaged mean flow and turbulence profiles in the wake flow are presented with and without spin along with comparison to published experimental data. Funded in part by the U. S. Army ARDEC, Picatinny Arsenal, NJ.

  2. Pulsatility role in cylinder flow dynamics at low Reynolds number

    KAUST Repository

    Qamar, Adnan

    2012-01-01

    We present dynamics of pulsatile flow past a stationary cylinder characterized by three non-dimensional parameters: the Reynolds number (Re), non-dimensional amplitude (A) of the pulsatile flow velocity, and Keulegan-Carpenter number (KC = Uo/Dωc). This work is motivated by the development of total artificial lungs (TAL) device, which is envisioned to provide ambulatory support to patients. Results are presented for 0.2 ≤ A ≤ 0.6 and 0.57 ≤ KC ≤ 2 at Re = 5 and 10, which correspond to the operating range of TAL. Two distinct fluid regimes are identified. In both regimes, the size of the separated zone is much greater than the uniform flow case, the onset of separation is function of KC, and the separation vortex collapses rapidly during the last fraction of the pulsatile cycle. The vortex size is independent of KC, but with an exponential dependency on A. In regime I, the separation point remains attached to the cylinder surface. In regime II, the separation point migrates upstream of the cylinder. Two distinct vortex collapse mechanisms are observed. For A < 0.4 and all KC and Re values, collapse occurs on the cylinder surface, whereas for A > 0.4 the separation vortex detaches from the cylinder surface and collapses at a certain distance downstream of the cylinder. The average drag coefficient is found to be independent of A and KC, and depends only on Re. However, for A > 0.4, for a fraction of the pulsatile cycle, the instantaneous drag coefficient is negative indicating a thrust production. © 2012 American Institute of Physics.

  3. Light diffusion in a radially N-layered cylinder.

    Science.gov (United States)

    Liemert, André; Kienle, Alwin

    2011-10-01

    Analytical solutions of the diffusion equation for a radially N-layered cylinder were derived in the steady-state, frequency, and time domains. Solutions for axially infinite and finite cylinders are presented. The derived formulas were compared to a known solution of the diffusion equation for a layered semi-infinite geometry and to Monte Carlo simulations, showing excellent and good agreement, respectively. The analytical solutions were applied to calculate the light propagation in models of the forearm and the finger, demonstrating the improvement in analysis of hemodynamics measurements compared to the formulas used so far.

  4. Plasmonic modes and extinction properties of a random nanocomposite cylinder

    Energy Technology Data Exchange (ETDEWEB)

    Moradi, Afshin, E-mail: a.moradi@kut.ac.ir [Department of Basic Sciences, Kermanshah University of Technology, Kermanshah, Iran and Department of Nano Science, Institute for Studies in Theoretical Physics and Mathematics (IPM), Tehran (Iran, Islamic Republic of)

    2014-04-15

    We study the properties of surface plasmon-polariton waves of a random metal-dielectric nanocomposite cylinder, consisting of bulk metal embedded with dielectric nanoparticles. We use the Maxwell-Garnett formulation to model the effective dielectric function of the composite medium and show that there exist two surface mode bands. We investigate the extinction properties of the system, and obtain the dependence of the extinction spectrum on the nanoparticles’ shape and concentration as well as the cylinder radius and the incidence angle for both TE and TM polarization.

  5. An experiment in heat conduction using hollow cylinders

    Energy Technology Data Exchange (ETDEWEB)

    Ortuno, M; Marquez, A; Gallego, S; Neipp, C; Belendez, A, E-mail: a.belendez@ua.es [Departamento de Fisica, IngenierIa de Sistemas y TeorIa de la Senal, Universidad de Alicante, Apartado 99, E-03080 Alicante (Spain)

    2011-07-15

    An experimental apparatus was designed and built to allow students to carry out heat conduction experiments in hollow cylinders made of different materials, as well as to determine the thermal conductivity of these materials. The evolution of the temperature difference between the inner and outer walls of the cylinder as a function of time is analysed, and when the process reaches the steady state regime the thermal conductivity can be easily calculated. Several materials such as wood, plastic and metals are considered and the values of their thermal conductivities, obtained experimentally, are compared with those given in the reference list.

  6. Transverse magnetic scattering by parallel conducting elliptic cylinders

    Science.gov (United States)

    Sebak, A.

    1991-10-01

    A boundary value solution to the problem of transverse magnetic multiple scattering by M parallel perfectly conducting elliptic cylinders is presented. The solution is an exact one and based on the separation-of-variables technique and the addition theorem for Mathieu functions. It is expressed in terms of a system of simultaneous linear equations of infinite order, which is then truncated for numerical computations. Representative numerical results for the scattered field by two cylinders are then generated, for some selected sizes and orientations parameters, and presented.

  7. Basic tests on 48Y-Cylinder for integrity evaluation

    International Nuclear Information System (INIS)

    Wataru, M.; Ozaki, S.; Kobayashi, S.; Gomi, Y.; Kosaki, A.; Yamakawa, H.; Fujiwara, H.

    1993-01-01

    In this study, tension test was carried out of carbon steel for moderate-/lower-temperature that is used for structural material of 48Y-cylinder at high temperature, and material strength data were obtained. By the test results, it was confirmed that measured strength data at temperature above 500degC did not make much difference from the former extrapolated data. The surface emissivity of the cylinder was measured at temperature up to 800degC, and it was confirmed that the emissivity is about 0.6 at temperature above 400degC. (J.P.N.)

  8. Black holes on cylinders are not algebraically special

    International Nuclear Information System (INIS)

    Smet, Pieter-Jan de

    2002-01-01

    We give a Petrov classification for five-dimensional metrics. We give an almost complete classification of Ricci-flat metrics that are static, have an SO(3) isometry group and have Petrov type 22. We use this classification to look for the metric of a black hole on a cylinder, i.e., a black hole with asymptotic geometry four-dimensional Minkowski space times a circle. Although a black string wrapped around the S 1 and the five-dimensional black hole are both algebraically special, it turns out that the black hole on a cylinder is not

  9. Assembly for electrical conductivity measurements in the piston cylinder device

    Science.gov (United States)

    Watson, Heather Christine [Dublin, CA; Roberts, Jeffrey James [Livermore, CA

    2012-06-05

    An assembly apparatus for measurement of electrical conductivity or other properties of a sample in a piston cylinder device wherein pressure and heat are applied to the sample by the piston cylinder device. The assembly apparatus includes a body, a first electrode in the body, the first electrode operatively connected to the sample, a first electrical conductor connected to the first electrode, a washer constructed of a hard conducting material, the washer surrounding the first electrical conductor in the body, a second electrode in the body, the second electrode operatively connected to the sample, and a second electrical conductor connected to the second electrode.

  10. Cylinder head fastening structure for internal combustion engines

    Energy Technology Data Exchange (ETDEWEB)

    Futakuchi, Y.; Oshiro, N.

    1988-01-26

    In a construction for an overhead cam internal combustion engine comprising a cylinder head adapted to be affixed to another component of the engine by at least one fastener having a tool receiving portion for tightening thereof and having a bearing cap affixed to the cylinder head and rotatably journaling the overhead camshaft, the improvement is described comprising the bearing cap having a portion overlying the fastener tool receiving portion, and means defining an access opening passing through the bearing cap and adapted to pass a tool for tightening of the fastener without removal of the bearing cap.

  11. Resonances and dipole moments in dielectric, magnetic, and magnetodielectric cylinders

    DEFF Research Database (Denmark)

    Dirksen, A.; Arslanagic, Samel; Breinbjerg, Olav

    2011-01-01

    An eigenfunction solution to the problem of plane wave scattering by dielectric, magnetic, and magnetodielectric cylinders is used for a systematic investigation of their resonances. An overview of the resonances with electric and magnetic dipole moments, needed in, e.g., the synthesis of metamat......An eigenfunction solution to the problem of plane wave scattering by dielectric, magnetic, and magnetodielectric cylinders is used for a systematic investigation of their resonances. An overview of the resonances with electric and magnetic dipole moments, needed in, e.g., the synthesis...

  12. Single-stranded DNA cleavage by divergent CRISPR-Cas9 enzymes

    Science.gov (United States)

    Ma, Enbo; Harrington, Lucas B.; O’Connell, Mitchell R.; Zhou, Kaihong; Doudna, Jennifer A.

    2015-01-01

    Summary Double-stranded DNA (dsDNA) cleavage by Cas9 is a hallmark of type II CRISPR-Cas immune systems. Cas9–guide RNA complexes recognize 20-base-pair sequences in DNA and generate a site-specific double-strand break, a robust activity harnessed for genome editing. DNA recognition by all studied Cas9 enzymes requires a protospacer adjacent motif (PAM) next to the target site. We show that Cas9 enzymes from evolutionarily divergent bacteria can recognize and cleave single-stranded DNA (ssDNA) by an RNA-guided, PAM-independent recognition mechanism. Comparative analysis shows that in contrast to the type II-A S. pyogenes Cas9 that is widely used for genome engineering, the smaller type II-C Cas9 proteins have limited dsDNA binding and unwinding activity and promiscuous guide-RNA specificity. These results indicate that inefficiency of type II-C Cas9 enzymes for genome editing results from a limited ability to cleave dsDNA, and suggest that ssDNA cleavage was an ancestral function of the Cas9 enzyme family. PMID:26545076

  13. Noncovalent DNA Binding Drives DNA Alkylation by Leinamycin. Evidence That the Z,E-5-(Thiazol-4-yl)-penta-2,4-dienone Moiety of the Natural Product Serves As An Atypical DNA Intercalator

    Science.gov (United States)

    Fekry, Mostafa I.; Szekely, Jozsef; Dutta, Sanjay; Breydo, Leonid; Zang, Hong; Gates, Kent S.

    2012-01-01

    Molecular recognition and chemical modification of DNA are important in medicinal chemistry, toxicology, and biotechnology. Historically, natural products have revealed many interesting and unexpected mechanisms for noncovalent DNA binding and covalent DNA modification. The studies reported here characterize the molecular mechanisms underlying the efficient alkylation of duplex DNA by the Streptomyces-derived natural product leinamycin. Previous studies suggested that alkylation of duplex DNA by activated leinamycin (2) is driven by noncovalent association of the natural product with the double helix. This is striking because leinamycin does not contain a classical noncovalent DNA-binding motif such as an intercalating unit, a groove binder, or a polycation. The experiments described here provide evidence that leinamycin is an atypical DNA-intercalating agent. A competition binding assay involving daunomycin-mediated inhibition of DNA alkylation by leinamycin provided evidence that activated leinamycin binds to duplex DNA with an apparent binding constant of approximately 4.3 ± 0.4 × 103 M−1. Activated leinamycin caused duplex unwinding and hydrodynamic changes in DNA-containing solutions that are indicative of DNA intercalation. Characterization of the reaction of activated leinamycin with palindromic duplexes containing 5'-CG and 5'-GC target sites, bulge-containing duplexes, and 5-methylcytosine-containing duplexes provided evidence regarding the orientation of leinamycin with respect to target guanine residues. The data allows construction of a model for the leinamycin-DNA complex suggesting how a modest DNA-binding constant combines with proper positioning of the natural product to drive efficient alkylation of guanine residues in the major groove of duplex DNA. PMID:21954957

  14. Effects of trypsin on cellular, chromosomal and DNA damage induced by X-rays

    Science.gov (United States)

    Sprunt, Elizabeth A.

    When cells are trypsinized before irradiation, potentiation of cell killing is seen; this is known as the 'trypsin effect'. The trypsin effect is re-examined here in the light of experiments in which enzymatic modifications of DNA in permeabilized cells has become a powerful experimental tool (Bryant et al, 1978, Ahnstrom and Bryant,1982; Natarajan et al, 1980; Bryant, 1984, 1985; Natarajan and Obe, 1984) and where in some cases it is suspected that trypsinization as part of the technique could significantly alter cell membrane permeability and chromatin structure (Obe et al, 1985; Obe and Winkel, 1985; Bryant and Christie, 1989). The trypsin effect was investigated at various cellular levels, assaying for cell survival (to verify the potentiation), anaphase chromosomal aberrations, DNA damage and repair and lastly using a nucleoid assay to investigate the effect of trypsin on DNA-nuclear matrix interactions. Each of these are considered in separate chapters as individual studies, then all compared in the final discussion. A small potentiation effect of X-ray damage on cell killing was seen when using Chinese Hamster Ovary (CHO) cells but no potentiating effect was found in the murine Ehrlich ascites tumour (EAT) cell line. Trypsinization was found to increase the number of X-ray induced chromosomal anaphase abnormalities in EAT cells. To investigate the possibility that the basis of the trypsin effect lies in its action at the DNA level, further experiments were performed to monitor DNA damage and repair using the DNA unwinding and neutral elution techniques. No difference was seen in the unwinding kinetics or in the DNA unwinding dose-effect curves for induction of DNA single strand breakage (ssb); when using neutral elution however. treatment of cells with trypsin or buffer alone increased the incidence of X-ray induced double strand breaks (dsb) at higher doses. Trypsinized EAT cells were found to repair ssb after 12 Gy less rapidly than those treated with

  15. Refractive cylinder outcomes after calculating toric intraocular lens cylinder power using total corneal refractive power

    Directory of Open Access Journals (Sweden)

    Davison JA

    2015-08-01

    Full Text Available James A Davison,1 Richard Potvin21Wolfe Eye Clinic, Marshalltown, IA, USA; 2Science in Vision, Akron, NY, USAPurpose: To determine whether the total corneal refractive power (TCRP value, which is based on measurement of both anterior and posterior corneal astigmatism, is effective for toric intraocular lens (IOL calculation with AcrySof® Toric IOLsPatients and methods: A consecutive series of cataract surgery cases with AcrySof toric IOL implantation was studied retrospectively. The IOLMaster® was used for calculation of IOL sphere, the Pentacam® TCRP 3.0 mm apex/ring value was used as the keratometry input to the AcrySof Toric IOL Calculator and the VERION™ Digital Marker for surgical orientation. The keratometry readings from the VERION reference unit were recorded but not used in the actual calculation. Vector differences between expected and actual residual refractive cylinder were calculated and compared to simulated vector errors using the collected VERION keratometry data.Results: In total, 83 eyes of 56 patients were analyzed. Residual refractive cylinder was 0.25 D or lower in 58% of eyes and 0.5 D or lower in 80% of eyes. The TCRP-based calculation resulted in a statistically significantly lower vector error (P<0.01 and significantly more eyes with a vector error ≤0.5 D relative to the VERION-based calculation (P=0.02. The TCRP and VERION keratometry readings suggested a different IOL toric power in 53/83 eyes. In these 53 eyes the TCRP vector error was lower in 28 cases, the VERION error was lower in five cases, and the error was equal in 20 cases. When the anterior cornea had with-the-rule astigmatism, the VERION was more likely to suggest a higher toric power and when the anterior cornea had against-the-rule astigmatism, the VERION was less likely to suggest a higher toric power.Conclusion: Using the TCRP keratometry measurement in the AcrySof toric calculator may improve overall postoperative refractive results

  16. Effect of High Porosity Screen on the Near Wake of a Circular Cylinder

    Directory of Open Access Journals (Sweden)

    Sahin B.

    2013-04-01

    Full Text Available The change in flow characteristics downstream of a circular cylinder (inner cylinder surrounded by a permeable cylinder (outer cylinder made of a high porosity screen was investigated in shallow water using Particle Image Velocimetry (PIV technique. The diameter of the inner cylinder, outer cylinder and the water height were kept constant during the experiments as d = 50 mm, D = 100 mm and hw = 50 mm, respectively. The depth-averaged free stream velocity was also kept constant as U = 180 mm/s which corresponded to a Reynolds number of Red = 9000 based on the inner cylinder diameter. It was shown that the outer permeable cylinder had a substantialeffect on the vortex formation and consequent vortex shedding downstream of the circular cylinder, especially in the near wake. The time averaged vorticity layers, streamlines and velocity vector field depict that the location of the interaction of vortices considerably changed by the presence of the outer cylinder. Turbulent statistics clearly demonstrated that in comparison to the natural cylinder, turbulent kinetic energy and Reynolds stresses decreased remarkably downstream of the inner cylinder. Moreover, spectra of streamwise velocity fluctuations showed that the vortex shedding frequency significantly reduced compared to the natural cylinder case.

  17. Semiconservative and unscheduled DNA-synthesis of rat thymocytes under the influence of some radioprotecting and radiosensitizing agents

    Energy Technology Data Exchange (ETDEWEB)

    Tempel, K.; Wulffius-Kock, M.; Winkle, J.; Schmerold, I.

    1982-02-01

    The effects of aminoethylisothiuroniumbromide (AET), cysteamine (CY-A), cysteine (CY-E), glutathione (GLU), mercaptoethanol (MA), mercaptopropionylglycine (MPG), N-ethylmaleimide (NEM), metronidazole (MNA), nitroacetophenone (NAP), nitrofurazone (NFA), arabinofuranosylcytosine (araC), fluorouracil (FU), adriamycin (AM), ethidiumbromide (E), bleomycin (BM), and diethyldithiocarbamate (DDC) on the semiconservative and unscheduled incorporation of /sup 3/H-thymidine into the DNA were tested on rat thymocytes in vitro. DNA damage has been measured using the hydroxylapatite system. Unscheduled DNA synthesis was induced by UV-light and/or X-irradiation. The semiconservative DNA synthesis was inhibited by the above substances-with exception of MA and MPG. Aminothioles, NAP, NFA, and BM enhanced, araC, FU, AM, E, and DDC diminished unscheduled DNA synthesis. After alkaline unwinding, the duplex form of DNA decreased under the influence of CY-A, CY-E, GLU, MPG, NEM, NAP, NFA, araC, FU, AM, E, and BM. It is suggested that stimulation of unscheduled DNA synthesis combined with a transient decrease of semiconservative DNA synthesis will amplify the DNA repair capacity of thymocytes, whereas radiation damage may be intensified by araC, FU, AM,E, and DDC - at least partly, through inhibition of unscheduled DNA synthesis. With respect to the action of NAP, NFA, and BM, DNA repair may be concerned in a more indirect manner.

  18. Heat convection in a set of three vertical cylinders

    International Nuclear Information System (INIS)

    Serrano Ramirez, M.L. de.

    1993-01-01

    Experimental results on temperature and heat flow in a set of three vertical cylinders with internal generation of heat, water submerged and in free convection are presented in this work . Temperature distribution, Nusselt number and convective coefficient (h) for each rod, developed for the distance between the axis of cylinders in vertical position, as a consequence of the application of power in its outside, are analyzed. Experimental information about heat transfer by free convection in vertical cylinders and surfaces is analyzed. Information of the several author who have carried out studies about the heat transfer on vertical cylinders was compiled, and the proposed equations with the experimental data obtained in the thermo fluids laboratory of National Institute of Nuclear Research (ININ) were tested. The way in which separation distance, s, distribution temperature array, Nusselt number, and convective coefficient calculated for the proposed channel with the Keyhani, Dutton and experimental equations are tabulated and they are plotted for each power value and for each separation between rods. The scheme of the used equipment and the experimentation description as well as the observations of tests and graphical results are included. (Author)

  19. Lift of a rotating circular cylinder in unsteady flows

    DEFF Research Database (Denmark)

    Carstensen, Stefan; Mandviwalla, Xerxes; Vita, Luca

    2012-01-01

    A cylinder rotating in steady current experiences a lift known as the Magnus effect. In the present study the effect of waves on the Magnus effect has been investigated. This situation is experienced with the novel floating offshore vertical axis wind turbine (VAWT) concept called the DEEPWIND...

  20. 49 CFR 178.35 - General requirements for specification cylinders.

    Science.gov (United States)

    2010-10-01

    ... of part 107 of this chapter; or (2) For DOT Specifications 3B, 3BN, 3E, 4B, 4BA, 4D (water capacity...) The word “spun” or “plug” must be placed near the DOT specification marking when an end closure in the... certifies that the processes of manufacture and heat treatment of cylinders were observed and found...

  1. 49 CFR 173.316 - Cryogenic liquids in cylinders.

    Science.gov (United States)

    2010-10-01

    ... filling density for hydrogen, cryogenic liquid is defined as the percent ratio of the weight of lading in... 49 Transportation 2 2010-10-01 2010-10-01 false Cryogenic liquids in cylinders. 173.316 Section... REQUIREMENTS FOR SHIPMENTS AND PACKAGINGS Gases; Preparation and Packaging § 173.316 Cryogenic liquids in...

  2. UF{sub 6} cylinder lifting equipment enhancements

    Energy Technology Data Exchange (ETDEWEB)

    Hortel, J.M. [Martin Marietta Energy Systems, Inc., Piketon, OH (United States)

    1991-12-31

    This paper presents numerous enhancements that have been made to the Portsmouth lifting equipment to ensure the safe handling of cylinders containing liquid uranium hexafluoride (UF{sub 6}). The basic approach has been to provide redundancy to all components of the lift path so that any one component failure would not cause the load to drop or cause any undesirable movement.

  3. Alternative method of retesting UF{sub 6} cylinders

    Energy Technology Data Exchange (ETDEWEB)

    Christ, R. [Nuclear Crago + Service GmbH, Hanau (Germany)

    1991-12-31

    The paper describes an alternative method to perform the periodic inspection of UF{sub 6} cylinders. The hydraulic test is replaced by ultrasonic checking of wall thickness and by magnetic particle testing of all the weld seams. Information about the legal background, the air leak test and the qualification of inspectors is also given.

  4. Temporary patching of damaged UF{sub 6} cylinders

    Energy Technology Data Exchange (ETDEWEB)

    Cardenas, A.L. [Martin Marietta Energy Systems, Inc., OH (United States)

    1991-12-31

    Patching techniques based on application of epoxy resins have been developed for temporarily repairing UF{sub 6} cylinders which have sustained relatively minor damage and must be safely emptied. The method is considerably faster and simpler than metallurgical weld repairs. Laboratory tests, detailed operational procedures, and case histories of experience at the Portsmouth Gaseous Diffusion Plant are described.

  5. Suppression of vortex shedding around a square cylinder using ...

    Indian Academy of Sciences (India)

    Direct numerical simulation (DNS) of flow past a square cylinder at a Reynolds number of 100 has been carried out to explore the effect of blowing in the form of jet(s) on vortex shedding. Higher order spatial as well as temporal discretization has been employed for the discretization of governing equations. The varying ...

  6. Facial and eye injury following a fridge cylinder gas explosion ...

    African Journals Online (AJOL)

    Facial and eye injury following a fridge cylinder gas explosion. Monsudi Kehinde Fasasi, Ehumadu Chioma Nwabugwu, Gero Na'allah Rumu. Abstract. No Abstract. Full Text: EMAIL FREE FULL TEXT EMAIL FREE FULL TEXT · DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT · AJOL African Journals Online. HOW TO ...

  7. 2D Flow around a Rectangular Cylinder: A Computational Study ...

    African Journals Online (AJOL)

    The velocity across the rectangular cylinders varies from 0.089 to 1.02m/s. The forces caused by vortex shedding phenomenon must be taken into account when designing buildings for safe, effective and economical engineering designs. Keywords: Vortex shedding, laminar, Aerodynamic, Strouhal number, Wake and Von ...

  8. 3D Flow around a Rectangular Cylinder: a review | Odesola ...

    African Journals Online (AJOL)

    Different simulations around bluff bodies were reviewed and the results obtained through different methodologies are presented. The effect of change by vortex shedding on the magnitude of fluid forces of rectangular cylinders are examined and reported. The aerodynamic integral parameters obtained from different papers ...

  9. Experimental and numerical thermal buckling studies on cylinders

    International Nuclear Information System (INIS)

    Brochard, J.; Combescure, A.; Locatelli, T.; Tomassian, R.

    1989-01-01

    An important program of buckling experiments is carried out by C.E.A./D.E.M.T on thin cylinders subjected to a very strong axial gradient of temperature, an axial tension stress, and an external pressure, in order to evaluate: - damage due to thermal buckling, - influence of a thermal load on reduction of buckling pressure, - progressive buckling under a cyclic thermal load

  10. Design of nested Halbach cylinder arrays for magnetic refrigeration applications

    Energy Technology Data Exchange (ETDEWEB)

    Trevizoli, Paulo V., E-mail: trevizoli@polo.ufsc.br; Lozano, Jaime A.; Peixer, Guilherme F.; Barbosa Jr, Jader R.

    2015-12-01

    We present an experimentally validated analytical procedure to design nested Halbach cylinder arrays for magnetic cooling applications. The procedure aims at maximizing the magnetic flux density variation in the core of the array for a given set of design parameters, namely the inner diameter of the internal magnet, the air gap between the magnet cylinders, the number of segments of each magnet and the remanent flux density of the Nd{sub 2}Fe{sub 14}B magnet grade. The design procedure was assisted and verified by 3-D numerical modeling using a commercial software package. An important aspect of the optimal design is to maintain an uniform axial distribution of the magnetic flux density in the region of the inner gap occupied by the active magnetocaloric regenerator. An optimal nested Halbach cylinder array was manufactured and experimentally evaluated for the magnetic flux density in the inner gap. The analytically calculated magnetic flux density variation agreed to within 5.6% with the experimental value for the center point of the magnet gap. - Highlights: • An analytical procedure to design nested Halbach cylinder arrays is proposed. • An optimal magnet configuration was built based on the analytical procedure. • The procedure was validated with 3D COMSOL simulations and experimental data.

  11. Foucault Dissipation in a Rolling Cylinder: A Webcam Quantitative Study

    Science.gov (United States)

    Bonanno, A.; Bozzo, G.; Camarca, M.; Sapia, P.

    2011-01-01

    In this paper we present an experimental strategy to measure the micro power dissipation due to Foucault "eddy" currents in a copper cylinder rolling on two parallel conductive rails in the presence of a magnetic field. Foucault power dissipation is obtained from kinematical measurements carried out by using a common PC webcam and video analysis…

  12. Infinitely long cylinder in a sinusoidal field (Problem 2)

    International Nuclear Information System (INIS)

    Ida, N.

    1986-01-01

    The results presented here were obtained with a 2-D (and axisymmetric) eddy current program called EDDYNDT. The program uses the magnetic vector potential formulation and was specifically designed for the calculation of coil impedances in NDT applications. For normal applications, flux densities, forces, eddy current densities and stored and dissipated energies are not calculated. The program required minor modifications to calculated these quantities form the magnetic vector potential. In its present form, program EDDYNDT cannot handle flux normal boundary conditions. To avoid this, half the cylinder was modeled as opposed to the quarter cylinder in the mesh recommended in the problem outline. This increased the number of elements and nodes but did not change their density or location. Both a solution without the cylinder and a solution with the cylinder are presented. The fields presented are calculated at the center of each element. For this reason, the values presented are interpolated between neighboring elements. This creates a problem, particularly at discontinuities where the errors are largest

  13. Unbalance and Balancing of the 4 Cylinder Engine: A Critical ...

    African Journals Online (AJOL)

    The 4 cylinder 4 stroke engine is the most widely used IC engine type for cars, light and medium commerical vehicles and tractors as well as for small and medium stationary applications. These engines work with either the Otto (spark ignition) or Diesel (compression ignition) operation cycles. The large scale of application ...

  14. Bubbly flows around a two-dimensional circular cylinder

    Science.gov (United States)

    Lee, Jubeom; Park, Hyungmin

    2016-11-01

    Two-phase cross flows around a bluff body occur in many thermal-fluid systems like steam generators, heat exchangers and nuclear reactors. However, our current knowledge on the interactions among bubbles, bubble-induced flows and the bluff body are limited. In the present study, the gas-liquid bubbly flows around a solid circular cylinder are experimentally investigated while varying the mean void fraction from 5 to 27%. The surrounding liquid (water) is initially static and the liquid flow is only induced by the air bubbles. For the measurements, we use the high-speed two-phase particle image velocimetry techniques. First, depending on the mean void fraction, two regimes are classified with different preferential concentration of bubbles in the cylinder wake, which are explained in terms of hydrodynamic force balances acting on rising bubbles. Second, the differences between the two-phase and single-phase flows (while matching their Reynolds numbers) around a circular cylinder will be discussed in relation to effects of bubble dynamics and the bubble-induced turbulence on the cylinder wake. Supported by a Grant (MPSS-CG-2016-02) through the Disaster and Safety Management Institute funded by Ministry of Public Safety and Security of Korean government.

  15. Suppression of vortex shedding around a square cylinder using ...

    Indian Academy of Sciences (India)

    Abstract. Direct numerical simulation (DNS) of flow past a square cylinder at a. Reynolds number of 100 has been carried out to explore the effect of blowing in the form of jet(s) on vortex shedding. Higher order spatial as well as temporal discretiza- tion has been employed for the discretization of governing equations.

  16. Viscoelastic flow simulations through an array of cylinders

    NARCIS (Netherlands)

    Gillissen, J.J.J.

    2013-01-01

    Polymer solution flow is studied numerically in a periodic, hexagonal array of cylinders as a model for a porous medium. We use a lattice Boltzmann method supplemented by a polymer stress, where the polymers are modeled as finitely extensible, nonlinear, elastic dumbbells. The simulated,

  17. Inflation of polymer melts into elliptic and circular cylinders

    DEFF Research Database (Denmark)

    Rasmussen, Henrik Koblitz; Christensen, Jens Horslund; Gøttsche, Søren

    2000-01-01

    of the inflating membrane is detected by fibreoptic sensors positioned in the cylinder. The pressure difference across the inflating membrane is measured as well. Measurements were performed on a polyisobutylene melt. As the deformation in this device is highly non-uniform, the response of the material is modelled...... simulations and experimental measurements of the membrane inflation....

  18. Closed-loop-manipulated wake of a stationary square cylinder

    Science.gov (United States)

    Zhang, M. M.; Zhou, Y.; Cheng, L.

    2005-07-01

    Vortex shedding from a fixed rigid square cylinder in a cross flow was manipulated by perturbing the cylinder surface using piezo-ceramic actuators, which were activated by a feedback hot-wire signal via a proportional integral derivative (PID) controller. The manipulated flow was measured at a Reynolds number (Re) of 7,400 using particle image velocimetry (PIV), laser-induced fluorescence (LIF) flow visualisation, two-component laser Doppler anemometry (LDA), hot wires and load cells. It is observed that the vortex circulation, fluctuating streamwise velocity, lift and drag coefficients and mean drag coefficient may decrease by 71%, 40%, 51%, 42% and 20%, respectively, compared with the unperturbed flow, if the perturbation velocity of the cylinder surface is anti-phased with the flow lateral velocity associated with vortex shedding. On the other hand, these quantities may increase by 152%, 90%, 60%, 67% and 37%, respectively, given in-phased cylinder surface perturbation and vortex shedding. Similar effects are obtained at Re=3,200 and 9,500, respectively. The relationship between the perturbation and flow modification is examined, which provides insight into the physics behind the observation.

  19. Large eight.cylinder Stirling engine for biofuels

    DEFF Research Database (Denmark)

    Carlsen, Henrik; Biedermann, F.; Bovin, Jonas Kabell

    2003-01-01

    A large Stirling engine with an electric power output of 70 kW has been developed for small-scale CHP using wood chips and other sorts of biomass as fuel. The development of the engine is based on the results from the development of a four-cylinder Stirling engine with a power output of 35 k......W, which has been reported before. The new 70 kW engine has eight cylinders, which are connected in a 2 x 4 double acting configuration. Like the four-cylinder engine, the eight-cylinder engine is designed as a hermetically sealed unit. A 75 kW asynchronous generator, which is incorporated...... transfer by radiation and heat transfer by convection. The convection part the heater has been optimised in order to obtain an equal distribution of heat transfer on each tube and at the same time maximise the heat transfer from the combustion products to the engine. In a double acting Stirling engine...

  20. Controlling a negative loaded hydraulic cylinder using pressure feedback

    DEFF Research Database (Denmark)

    Hansen, M.R.; Andersen, T.O.

    2010-01-01

    This paper is concerned with the inherent oscillatory nature of pressure compensated velocity control of a hydraulic cylinder subjected to a negative load and suspended by means of an over-center valve. Initially, a linearized stability analysis of such a hydraulic circuit is carried out clearly ...... in a nonlinear time domain simulation model validating the linear stability analysis....

  1. Molecular architecture of the recombinant human MCM2-7 helicase in complex with nucleotides and DNA

    DEFF Research Database (Denmark)

    Boskovic, Jasminka; Bragado-Nilsson, Elisabeth; Saligram Prabhakar, Bhargav

    2016-01-01

    DNA replication is a key biological process that involves different protein complexes whose assembly is rigorously regulated in a successive order. One of these complexes is a replicative hexameric helicase, the MCM complex, which is essential for the initiation and elongation phases of replication....... After the assembly of a double heterohexameric MCM2-7 complex at replication origins in G1, the 2 heterohexamers separate from each other and associate with Cdc45 and GINS proteins in a CMG complex that is capable of unwinding dsDNA during S phase. Here, we have reconstituted and characterized...... the purified human MCM2-7 (hMCM2-7) hexameric complex by co-expression of its 6 different subunits in insect cells. The conformational variability of the complex has been analyzed by single particle electron microscopy in the presence of different nucleotide analogs and DNA. The interaction with nucleotide...

  2. Non-essential MCM-related proteins mediate a response to DNA damage in the archaeon Methanococcus maripaludis.

    Science.gov (United States)

    Walters, Alison D; Chong, James P J

    2017-05-01

    The single minichromosome maintenance (MCM) protein found in most archaea has been widely studied as a simplified model for the MCM complex that forms the catalytic core of the eukaryotic replicative helicase. Organisms of the order Methanococcales are unusual in possessing multiple MCM homologues. The Methanococcus maripaludis S2 genome encodes four MCM homologues, McmA-McmD. DNA helicase assays reveal that the unwinding activity of the three MCM-like proteins is highly variable despite sequence similarities and suggests additional motifs that influence MCM function are yet to be identified. While the gene encoding McmA could not be deleted, strains harbouring individual deletions of genes encoding each of the other MCMs display phenotypes consistent with these proteins modulating DNA damage responses. M. maripaludis S2 is the first archaeon in which MCM proteins have been shown to influence the DNA damage response.

  3. Variation in assessment of oxidatively damaged DNA in mononuclear blood cells by the comet assay with visual scoring

    DEFF Research Database (Denmark)

    Forchhammer, Lykke; Bräuner, Elvira Vaclavik; Folkmann, Janne Kjaersgaard

    2008-01-01

    The comet assay is popular for assessments of genotoxicity, but the comparison of results between studies is challenging because of differences in experimental procedures and reports of DNA damage in different units. We investigated the variation of DNA damage in mononuclear blood cells (MNBCs......) measured by the comet assay with focus on the variation related to alkaline unwinding and electrophoresis time, number of cells scored, as well as the putative benefits of transforming the primary end points to common units by the use of reference standards and calibration curves. Eight experienced......, our results indicate that inter-investigator difference in scoring is a strong determinant of DNA damage levels measured by the comet assay....

  4. Natural convection heat transfer from horizontal concentric and eccentric cylinder systems cooling in the ambient air and determination of inner cylinder location

    Science.gov (United States)

    Atayılmaz, Ş. Özgür; Demir, Hakan; Sevindir, Mustafa Kemal; Ağra, Özden; Teke, İsmail; Dalkılıç, Ahmet Selim

    2017-08-01

    Heat transfer characteristics of horizontal copper concentric cylinders in the case of natural convection was investigated numerically and experimentally. While the inner cylinder had an electric heater to keep it at a constant temperature, annulus was filled with water. There were two different test sections as bare and concentric cylinder systems located in different ambient temperatures in a conditioned room for the comparison of the results. Comparison of average Nusselt numbers for the air side of the concentric cylinder system and the effective thermal conductivity of the annulus were calculated with both experimental data, numerical results and a well-known correlation. Annulus and the air side isotherms and streamlines are shown for RaL = 9 × 105-5 × 106 and Ra = 2 × 105-7 × 105 respectively. Additionally, a numerical study was conducted by forming eccentric cylinder systems to determine the optimum location of inner cylinder to maximize the heat transfer rate. Comparison of heat transfer rates from bare and concentric horizontal cylinders were done under steady state conditions. Heat transfer enhancement, the effect of the decrease in condensing temperature of the inner cylinder surface on COP of an ideal Carnot refrigeration cycle and rise in COP were determined in the study. Also the optimum location of inner cylinder to maximize the heat transfer rate was determined as at the bottom quadrant of outer cylinder.

  5. Dual daughter strand incision is processive and increases the efficiency of DNA mismatch repair.

    Science.gov (United States)

    Hermans, Nicolaas; Laffeber, Charlie; Cristovão, Michele; Artola-Borán, Mariela; Mardenborough, Yannicka; Ikpa, Pauline; Jaddoe, Aruna; Winterwerp, Herrie H K; Wyman, Claire; Jiricny, Josef; Kanaar, Roland; Friedhoff, Peter; Lebbink, Joyce H G

    2016-08-19

    DNA mismatch repair (MMR) is an evolutionarily-conserved process responsible for the repair of replication errors. In Escherichia coli, MMR is initiated by MutS and MutL, which activate MutH to incise transiently-hemimethylated GATC sites. MMR efficiency depends on the distribution of these GATC sites. To understand which molecular events determine repair efficiency, we quantitatively studied the effect of strand incision on unwinding and excision activity. The distance between mismatch and GATC site did not influence the strand incision rate, and an increase in the number of sites enhanced incision only to a minor extent. Two GATC sites were incised by the same activated MMR complex in a processive manner, with MutS, the closed form of MutL and MutH displaying different roles. Unwinding and strand excision were more efficient on a substrate with two nicks flanking the mismatch, as compared to substrates containing a single nick or two nicks on the same side of the mismatch. Introduction of multiple nicks by the human MutLα endonuclease also contributed to increased repair efficiency. Our data support a general model of prokaryotic and eukaryotic MMR in which, despite mechanistic differences, mismatch-activated complexes facilitate efficient repair by creating multiple daughter strand nicks. © The Author(s) 2016. Published by Oxford University Press on behalf of Nucleic Acids Research.

  6. Induction of DNA strand breaks in 14C-labelled cells

    International Nuclear Information System (INIS)

    Sundell-Bergman, S.; Johanson, K.J.

    1979-01-01

    Chinese hamster cells grown in vitro were labelled with 14 C-thymidine for 18 hours and after 3 hours in non-radioactive medium they were stored at 0 0 C for various periods ( 1 to 12 hours). During this treatment a number of DNA strand breaks were induced by 14 C decay which were not repaired at 0 0 C. The number of DNA strand breaks was determined using the DNA unwinding technique. At 0.5-1 dpm per cell a detectable number of DNA strand breaks were found. Treatment for six hours (1 dpm per cell) reduced the percentage of double-stranded DNA from 80 to 70%, corresponding to about 750 DNA strand breaks per cell. The rejoining of DNA strand breaks was studied after treatment for 12 hours at 0 0 C followed by incubation of the cells for various periods at 37 0 C. Most of the DNA strand breaks induced by 14 C decay at 0 0 C were repaired after incubation at 37 0 C for 15 minutes. Assuming an absorbed dose of 1.8 mGy per 14 C decay to the cell nucleus an RBE value close to 1 was found for internal irradiation from 14 C decay as compared with 60 Co-gamma irradiation. (author)

  7. Double-stranded DNA dissociates into single strands when dragged into a poor solvent.

    Science.gov (United States)

    Cui, Shuxun; Yu, Jin; Kühner, Ferdinand; Schulten, Klaus; Gaub, Hermann E

    2007-11-28

    DNA displays a richness of biologically relevant supramolecular structures, which depend on both sequence and ambient conditions. The effect of dragging double-stranded DNA (dsDNA) from water into poor solvent on the double-stranded structure is still unclear because of condensation. Here, we employed single molecule techniques based on atomic force microscopy and molecular dynamics (MD) simulations to investigate the change in structure and mechanics of DNA during the ambient change. We found that the two strands are split apart when the dsDNA is pulled at one strand from water into a poor solvent. The findings were corroborated by MD simulations where dsDNA was dragged from water into poor solvent, revealing details of the strand separation at the water/poor solvent interface. Because the structure of DNA is of high polarity, all poor solvents show a relatively low polarity. We speculate that the principle of spontaneous unwinding/splitting of dsDNA by providing a low-polarity (in other word, hydrophobic) micro-environment is exploited as one of the catalysis mechanisms of helicases.

  8. Sequence-influenced interactions of oligoacridines with DNA detected by retarded gel electrophorectic migrations

    International Nuclear Information System (INIS)

    Nielsen, P.E.; Zhen, W.; Henriksen, U.; Buchardt, O.

    1988-01-01

    The authors have found that di-, tri-, tetra-, and hexa-9-acridinylamines are so efficiently associated with DNA during electrophoresis in polyacrylamide or agarose gels that they retard its migration. The retardation is roughly proportional to the reagent to base pair ratio, and the magnitude of the retardation indicates that a combined charge neutralization/helix extension mechanism is mainly responsible for the effect. Furthermore, DNA sequence dependent differences are observed. Thus, the pUC 19 restriction fragments (HaeIII or AluI), which in the native state comigrate upon gel electrophoretic analysis, could be separated in the presence of a diacridine, and specific DNA fragments responded differently to different diacridines. These results suggest that the effect also is due to a contribution from the DNA conformation and that the DNA conformation dynamics are influenced differently upon binding of different diacridines. They foresee three applications of this observation: (1) in analytical gel electrophoretic separation of otherwise comigrating DNA molecules, (2) in studies of polyintercalator-DNA interaction, and (3) in measurements of polyintercalator-induced DNA unwinding

  9. Gas cylinder disposal pit remediation waste minimization and management

    International Nuclear Information System (INIS)

    Alas, C.A.; Solow, A.; Criswell, C.W.; Spengler, D.; Brannon, R.; Schwender, J.M.; Eckman, C.K.; Rusthoven, T.

    1995-01-01

    A remediation of a gas cylinder disposal pit at Sandia National Laboratories, New Mexico has recently been completed. The cleanup prevented possible spontaneous releases of hazardous gases from corroded cylinders that may have affected nearby active test areas at Sandia's Technical Area III. Special waste management, safety, and quality plans were developed and strictly implemented for this project. The project was conceived from a waste management perspective, and waste minimization and management were built into the planning and implementation phases. The site layout was planned to accommodate light and heavy equipment, storage of large quantities of suspect soil, and special areas to stage and treat gases and reactive chemicals removed from the pit, as well as radiation protection areas. Excavation was a tightly controlled activity using experienced gas cylinder and reactive chemical specialists. Hazardous operations were conducted at night under lights, to allow nearby daytime operations to function unhindered. The quality assurance plan provided specific control of, and documentation for, critical decisions, as well as the record of daily operations. Both hand and heavy equipment excavation techniques were utilized. Hand excavation techniques were utilized. Hand excavation techniques allows sealed glass containers to be exhumed unharmed. In the end, several dozen thermal batteries; 5 pounds (2.3 kg) of lithium metal; 6.6 pounds (3.0 kg) of rubidium metal; several kilograms of unknown chemicals; 140 cubic yards (107 cubic meters) of thorium-contaminated soil; 270 cubic yards (205 cubic meters) of chromium-contaminated soil; and 450 gas cylinders, including 97 intact cylinders containing inert, flammable, toxic, corrosive, or oxidizing gases were removed and effectively managed to minimize waste

  10. Fracture analysis of the NESC-1 spinning cylinder experiment

    International Nuclear Information System (INIS)

    Keeney, J.A.; Bass, B.R.

    1995-01-01

    This paper presents finite-element analyses of the cylinder specimen being used in the international Network for Evaluating Steel Components (NESC) large-scale spinning-cylinder project (NESC-1). The objective of the NESC-1 project is to focus on a complete process for assessing the structural integrity of aged reactor pressure vessels. A new cylinder specimen was reconstituted from segments of the previously tested SC-4 and SC-6 specimens because the relatively high fracture toughness of the original specimen might preclude achieving the test objectives. The wall thickness is greater for the reconstituted specimen when compared with the previous specimen geometry (175 vs 150 mm). Also, the initial and coolant temperatures for the proposed thermal shock may be reduced as much as 25 C to increase the probability of achieving cleavage initiation. Analyses were carried out to determine the combined effects of increasing the wall thickness and lowering the initial and coolant temperatures in the experiment. Estimates were made of the change in hoop strain on the clad inner surface directly above a subclad crack due to initiation and axial propagation of cladded cylinder were generated with 6:1 and 2:1 semielliptical 70-mm-deep subclad cracks. The cylinder specimen was subjected to thermal-shock and centrifugal loading conditions and analyzed with a thermo-elastic-plastic material model. The analytical results indicate that lowering the initial and coolant temperatures by 25 C will not significantly change the peak driving force, but will shift the stress-intensity factor (K I ) vs temperature curves so that the crack will become critical at an earlier time in the transient. The peak K I value occurs at a lower temperature, which increases the probability of achieving cleavage initiation. Also, the calculated hoop strains for the two crack aspect ratios provide an estimated change in hoop strain inn the range of 3 to 4% on the clad inner surface

  11. Fracture analysis of the NESC-1 spinning cylinder experiment

    International Nuclear Information System (INIS)

    Keeney, J.A.; Bass, B.R.

    1995-01-01

    This paper presents finite-element analyses of the cylinder specimen being used in the international Network for Evaluating Steel Components (NESC) large-scale spinning-cylinder project (NESC-1). The objective of the NESC-1 project is to focus on a complete process for assessing the structural integrity of aged reactor pressure vessels. A new cylinder specimen was reconstituted from segments of the previously tested SC-4 and SC-6 specimens because the relatively high fracture toughness of the original specimen might preclude achieving the test objectives. Also, the initial and coolant temperatures for the proposed thermal shock may be reduced as much as 25 C to increase the probability of achieving cleavage initiation. Analyses were carried out to determine the combined effects of increasing the wall thickness and lowering the initial and coolant temperatures in the experiment. Estimates were made of the change in hoop strain on the clad inner surface directly above a subclad crack due to initiation and axial propagation of the crack. Three-dimensional finite-element models of the cladded cylinder were generated with 6:1 and 2:1 semielliptical 70-mm-deep subclad cracks. The cylinder specimen was subjected to thermal-shock and centrifugal loading conditions and analyzed with a thermo-elastic-plastic material model. The analytical results indicate that lowering the initial and coolant temperatures by 25 C will not significantly change the peak driving force, but will shift the stress-intensity factor (K I ) vs temperature curves so that the crack will become critical at an earlier time in the transient. The peak K I value occurs at a lower temperature which increases the probability of achieving cleavage initiation

  12. Structure of DNA damaged by UV and psoralen

    International Nuclear Information System (INIS)

    Sung-hou Kim; Tomic, M.T.; Wemmer, D.E.; Pearlman, D.; Holbrook, S.

    1988-01-01

    The authors have used NMR methods to determine a three-dimensional model of an 8 base-pair DNA fragment cross-linked with psoralen. The duplex form of the self-complementary deoxyribonucleotide d-GGGTACCC, contains a psoralen cross-linkable site at the center of the duplex. The cross-link was formed by UV irradiation of a mixture of the purified DNA octamer and 4'-(aminomethyl)-4,5',8-trimethylpsoralen (AMT). Structural information was obtained using one and two-dimensional NMR techniques. Two-dimensional NOE experiments were used to assign the spectrum and estimate distances for many pairs of protons in the cross-linked DNA. Structural parameters obtained are qualitatively consistent with a previously proposed model for kinked and unwound cross-linked B-form DNA derived from crystallography and molecular modeling. The NMR derived model has a 53 degree bend into the major groove occuring primarily at the site of drug addition, and a 56 degree unwinding spanning the 8 base pair duplex. (author)

  13. Shaping the Microstructure of Cast Iron Automobile Cylinder Liners Aimed at Providing High Service Properties

    Directory of Open Access Journals (Sweden)

    Orłowicz A.W.

    2015-06-01

    Full Text Available The paper presents an analysis of factors affecting the wear of cylinder liners. The effect of the graphite precipitation morphology on the cylinder liner wear mechanism is presented. Materials used to cast cylinder liners mounted in a number of engines have been examined for their conformity with requirements set out in applicable Polish industrial standard. A casting for a prototype cylinder liner has been made with a microstructure guaranteeing good service properties of the part.

  14. Conceptual Ideas for New Nondestructive UF6 Cylinder Assay Techniques

    Energy Technology Data Exchange (ETDEWEB)

    Miller, Karen A. [Los Alamos National Laboratory

    2012-05-02

    Nondestructive assay (NDA) measurements of uranium cylinders play an important role in helping the International Atomic Energy Agency (IAEA) safeguard uranium enrichment plants. Traditionally, these measurements have consisted of a scale or load cell to determine the mass of UF{sub 6} in the cylinder combined with a gamma-ray measurement of the 186 keV peak from {sup 235}U to determine enrichment. More recently, Los Alamos National Laboratory (LANL) and Pacific Northwest National Laboratory (PNNL) have developed systems that exploit the passive neutron signal from UF{sub 6} to determine uranium mass and/or enrichment. These include the Uranium Cylinder Assay System (UCAS), the Passive Neutron Enrichment Meter (PNEM), and the Hybrid Enrichment Verification Array (HEVA). The purpose of this report is to provide the IAEA with new ideas on technologies that may or may not be under active development but could be useful for UF{sub 6} cylinder assay. To begin, we have included two feasibility studies of active interrogation techniques. There is a long history of active interrogation in the field of nuclear safeguards, especially for uranium assay. Both of the active techniques provide a direct measure of {sup 235}U content. The first is an active neutron method based on the existing PNEM design that uses a correlated {sup 252}Cf interrogation source. This technique shows great promise for UF{sub 6} cylinder assay and is based on advanced technology that could be implemented in the field in the near term. The second active technique is nuclear resonance fluorescence (NRF). In the NRF technique, a bremsstrahlung photon beam could be used to illuminate the cylinder, and high-resolution gamma-ray detectors would detect the characteristic de-excitation photons. The results of the feasibility study show that under certain measurement geometries, NRF is impractical for UF6 cylinder assay, but the 'grazing transmission' and 'secant transmission' geometries

  15. Gas-lubricated seal for sealing between a piston and a cylinder wall

    Science.gov (United States)

    Hoult, D.P.

    1985-09-10

    A piston-cylinder seal uses gas for a lubricant and has a runner supported on a gapless structure and placed in the space between the piston and the cylinder wall. The runner is deformed elastically under the influence of the operating pressures to follow and compensate for variations in the piston-cylinder fit and maintain a seal. 4 figs.

  16. 77 FR 64590 - Safety Advisory: Unauthorized Marking of Compressed Gas Cylinders

    Science.gov (United States)

    2012-10-22

    .... PHMSA-2012-0170, Notice No. 12-7] Safety Advisory: Unauthorized Marking of Compressed Gas Cylinders... of high pressure compressed gas cylinders by George Welding & Supply Co., Inc. located at 205 Tombs... compressed gas cylinders as being properly requalified in accordance with the Hazardous Materials Regulations...

  17. 30 CFR 75.1106-3 - Storage of liquefied and nonliquefied compressed gas cylinders; requirements.

    Science.gov (United States)

    2010-07-01

    ... compressed gas cylinders; requirements. 75.1106-3 Section 75.1106-3 Mineral Resources MINE SAFETY AND HEALTH... Fire Protection § 75.1106-3 Storage of liquefied and nonliquefied compressed gas cylinders; requirements. (a) Liquefied and nonliquefied compressed gas cylinders stored in an underground coal mine shall...

  18. 41 CFR 50-204.65 - Inspection of compressed gas cylinders.

    Science.gov (United States)

    2010-07-01

    ... gas cylinders. 50-204.65 Section 50-204.65 Public Contracts and Property Management Other Provisions... FEDERAL SUPPLY CONTRACTS Gases, Vapors, Fumes, Dusts, and Mists § 50-204.65 Inspection of compressed gas cylinders. Each contractor shall determine that compressed gas cylinders under his extent that this can be...

  19. 30 CFR 75.1106-2 - Transportation of liquefied and nonliquefied compressed gas cylinders; requirements.

    Science.gov (United States)

    2010-07-01

    ... compressed gas cylinders; requirements. 75.1106-2 Section 75.1106-2 Mineral Resources MINE SAFETY AND HEALTH... Fire Protection § 75.1106-2 Transportation of liquefied and nonliquefied compressed gas cylinders; requirements. (a) Liquefied and nonliquefied compressed gas cylinders transported into or through an...

  20. 78 FR 42817 - Safety Advisory: Unauthorized Filling of Compressed Gas Cylinders

    Science.gov (United States)

    2013-07-17

    .... PHMSA-2013-0176, Notice No. 13-11] Safety Advisory: Unauthorized Filling of Compressed Gas Cylinders... transportation high pressure compressed gas cylinders without verifying that they met the appropriate safety... high pressure US DOT and special permit cylinders with compressed gases without verifying that they met...

  1. 49 CFR 180.209 - Requirements for requalification of specification cylinders.

    Science.gov (United States)

    2010-10-01

    ... mixtures of these gases with up to 30 percent by volume of carbon dioxide, provided the gas has a dew point....205(i). This provision does not apply to cylinders used for carbon dioxide, fire extinguisher or other... all traces of water. (v) The cylinder is not used for underwater breathing. (vi) Each cylinder is...

  2. Conditions for pure rolling of a heavy cylinder along a brachistochrone

    Science.gov (United States)

    Legeza, V. P.

    2010-11-01

    Algebraic equations for the line of steepest descent of a cylinder are derived in parametric form. Conditions for rolling without slipping and separation of the cylinder along a brachistochrone are established based on the equations of motion with constraint reaction. The important conclusion is drawn that the center of mass of a cylinder moving along a brachistochrone describes a cycloid

  3. Vorticity generation and wake transition for a translating circular cylinder: Wall proximity and rotation effects

    DEFF Research Database (Denmark)

    Hourigan, K.; Rao, A.; Brøns, Morten

    2013-01-01

    dramatically under the influence of cylinder rotation and wall proximity. At gaps between the cylinder and the wall of less than approximately 0.25 cylinder diameter, the wake becomes three dimensional prior to becoming unsteady, while for larger gaps the initial transition is to an unsteady two...

  4. Classification of gap flow regimes in two side-by-side circular cylinders

    CSIR Research Space (South Africa)

    Atkins, M

    2014-02-01

    Full Text Available at an intermediate gap spacing ranging between e.g., 1.2 = T/D = 2.2. The flow passing between the cylinders - gap flow - is biased towards one cylinder (Fig.1.(b)). The wake pattern behind that cylinder has a narrow near-wake (n) with a higher vortex shedding...

  5. Formation of whispering gallery modes by scattering of an electromagnetic plane wave by two cylinders

    Energy Technology Data Exchange (ETDEWEB)

    Abramov, Arnold, E-mail: qulaser@gmail.com [Kuang-Chi Institute of Advanced Technology, Shenzhen, 518057 (China); Kostikov, Alexander [Donbass State Engineering Academy, 84303, Kramatorsk, Donetsk (Ukraine)

    2017-03-26

    We report the effect of scattering of electromagnetic plane waves by two cylinders on whispering gallery mode (WGM) formation in a cylinder. WGM can occur because of the presence of additional cylinder scatterers at specific location, while WGMs can only form in a single cylinder for specific cylinder radius and/or wavelength values, the matching accuracy required would be much greater than that required in our model for the additional cylinders locations. Analysis of the general solution to the problem showed that the effect can be explained by the interference of waves scattered by additional cylinders and incident on the main cylinder. - Highlights: • We consider scattering of electromagnetic plane waves by two cylinders. • WGMs occur because of the presence of additional cylinder at specific location. • The accuracy for the locations is much less than required for specific values of single cylinder. • The interference of waves scattered by additional cylinders and incident on the main is responsible for the effect.

  6. Stokes flow past a swarm of porous circular cylinders with Happel ...

    Indian Academy of Sciences (India)

    The problem of creeping flow past a swarm of porous circular cylinders with Happel and Kuwabara boundary conditions is investigated. The Brinkman equation for the flow inside the porous cylinder and the Stokes equation outside the porous cylinder in their stream function formulations are used. The force experienced by ...

  7. Conformation effects of CpG methylation on single-stranded DNA oligonucleotides: analysis of the opioid peptide dynorphin-coding sequences.

    Directory of Open Access Journals (Sweden)

    Malik Mumtaz Taqi

    Full Text Available Single-stranded DNA (ssDNA is characterized by high conformational flexibility that allows these molecules to adopt a variety of conformations. Here we used native polyacrylamide gel electrophoresis (PAGE, circular dichroism (CD spectroscopy and nuclear magnetic resonance (NMR spectroscopy to show that cytosine methylation at CpG sites affects the conformational flexibility of short ssDNA molecules. The CpG containing 37-nucleotide PDYN (prodynorphin fragments were used as model molecules. The presence of secondary DNA structures was evident from differences in oligonucleotide mobilities on PAGE, from CD spectra, and from formation of A-T, G-C, and non-canonical G-T base pairs observed by NMR spectroscopy. The oligonucleotides displayed secondary structures at 4°C, and some also at 37°C. Methylation at CpG sites prompted sequence-dependent formation of novel conformations, or shifted the equilibrium between different existing ssDNA conformations. The effects of methylation on gel mobility and base pairing were comparable in strength to the effects induced by point mutations in the DNA sequences. The conformational effects of methylation may be relevant for epigenetic regulatory events in a chromatin context, including DNA-protein or DNA-DNA recognition in the course of gene transcription, and DNA replication and recombination when double-stranded DNA is unwinded to ssDNA.

  8. Structure of the Cpf1 endonuclease R-loop complex after target DNA cleavage

    DEFF Research Database (Denmark)

    Stella, Stefano; Alcón, Pablo; Montoya, Guillermo

    2017-01-01

    involved in DNA unwinding to form a CRISPR RNA (crRNA)-DNA hybrid and a displaced DNA strand. The protospacer adjacent motif (PAM) is recognized by the PAM-interacting domain. The loop-lysine helix-loop motif in this domain contains three conserved lysine residues that are inserted in a dentate manner...... into the double-stranded DNA. Unzipping of the double-stranded DNA occurs in a cleft arranged by acidic and hydrophobic residues facilitating the crRNA-DNA hybrid formation. The PAM single-stranded DNA is funnelled towards the nuclease site through a mixed hydrophobic and basic cavity. In this catalytic...... conformation, the PAM-interacting domain and the helix-loop-helix motif in the REC1 domain adopt a 'rail' shape and 'flap-on' conformations, respectively, channelling the PAM strand into the cavity. A steric barrier between the RuvC-II and REC1 domains forms the 'septum', separating the displaced PAM strand...

  9. Inhibition of DNA replication and repair by anthralin or danthron in cultured human cells

    Energy Technology Data Exchange (ETDEWEB)

    Clark, J.M.; Hanawalt, P.C.

    1982-07-01

    The comparative effects of the tumor promoter anthralin and its analog, danthron, on semiconservative DNA replication and DNA repair synthesis were studied in cultured human cells. Bromodeoxyuridine was used as density label together with /sup 3/H-thymidine to distinguish replication from repair synthesis in isopycnic CsCl gradients. Anthralin at 1.1 microgram inhibited replication in T98G cells by 50%. In cells treated with 0.4 or 1.3 microM anthralin and additive effect was observed on the inhibition of replication by ultraviolet light (254 nm). In cells irradiated with 20 J/m2, 2.3 microM anthralin was required to inhibit repair synthesis by 50%. Thus there was no selective inhibitory effect of anthralin on repair synthesis. Danthron exhibited no detectable effect on either semiconservative replication or repair synthesis at concentrations below about 5.0 microM. Neither compound stimulated repair synthesis in the absence of ultraviolet irradiation. Thus, anthralin and danthron do not appear to react with DNA to form adducts that are subject to excision repair. Although both compounds appear to intercalate into supercoiled DNA in vitro to a limited extent, the degree of unwinding introduced by the respective drugs does not correlate with their relative effects on DNA synthesis in vivo. Therefore the inhibitory effect of anthralin on DNA replication and repair synthesis in T98G cells does not appear to result from the direct interaction of the drug with DNA.

  10. Improvement of the Magnetic Shielding Effects by the Superposition of a Multi-Layered Ferromagnetic Cylinder over an HTS Cylinder: Relationship Between the Shielding Effects and the Layer Number of the Ferromagnetic Cylinder

    International Nuclear Information System (INIS)

    Yasui, K; Tarui, Y; Itoh, M

    2006-01-01

    The idealized magnetic shielded vessel can be realized by making use of a high-critical temperature superconductor (HTS). It is difficult for practical applications, however, to fabricate a shielding vessel that has a high value of the maximum shielded magnetic flux density B s0 . The present authors have improved the value of B s0 for the Bi-Pb-Sr-Ca-Cu-O (BPSCCO) cylinder used as the shielding vessel, by the superposition of a four-layered softiron cylinder over the BPSCCO cylinder, termed the four-layered superimposed cylinder. The B s4 value of 610 x 10 -4 T for the four-layered superimposed cylinder, is found to be about 4 times larger than that of a single-BPSCCO cylinder, and is theoretically analyzed by use of a new analysis method. The experimental values of the maximum shielded magnetic flux density B sn of n-layered superimposed cylinders are found to agree well with those of the theoretical analysis. Experimental results revealed several characteristics of the magnetic shielding within the n-layered superimposed cylinders. Also discussed is the new analysis method for the relationship between the n and B sn

  11. Two cylinder permanent magnet stirrer for liquid metals

    Science.gov (United States)

    Bojarevičs, A.; Baranovskis, R.; Kaldre, I.; Milgrāvis, M.; Beinerts, T.

    2017-07-01

    To achieve a uniform liquid metal composition and temperature distribution, stirring is often necessary for industrial processes. Here, a novel permanent magnet system for liquid melt stirring is proposed. It promises very low energy consumption and options for multiple different flow types compared to traditional travelling magnetic field inductors or mechanical stirrers. The proposed system has a simple design: it consists of two rotating permanent magnet cylinders, which are magnetized transversely to the axis of the cylinders. The experimental device was developed and tested under various regimes using GaInSn alloy in a cylindrical crucible. Aluminum stirring by permanent magnets in laboratory scale is tested, and stirring impact on directional solidification of metallic alloys is experimentally investigated.

  12. Transient thermal stresses in a circular cylinder with constrained ends

    International Nuclear Information System (INIS)

    Goshima, Takahito; Miyao, Kaju

    1986-01-01

    This paker deals with the transient thermal stresses in a finite circular cylinder constrained at both end surfaces and subjected to axisymmetric temperature distribution on the lateral surface. The thermoelastic problem is formulated in terms of a thermoelastic displacement potential and three harmonic stress functions. Numerical calculations are carried out for the case of the uniform temperature distribution on the lateral surface. The stress distributions on the constrained end and the free suface are shown graphically, and the singularity in stresses appearing at the circumferencial edge is considered. Moreover, the approximate solution based upon the plane strain theory is introduced in order to compare the rigorous one, and it is considered how the length of the cylinder and the time proceeds affect on the accuracy of the approximation. (author)

  13. Circular cylinders and pressure vessels stress analysis and design

    CERN Document Server

    Vullo, Vincenzo

    2014-01-01

    This book provides comprehensive coverage of stress and strain analysis of circular cylinders and pressure vessels, one of the classic topics of machine design theory and methodology. Whereas other books offer only a partial treatment of the subject and frequently consider stress analysis solely in the elastic field, Circular Cylinders and Pressure Vessels broadens the design horizons, analyzing theoretically what happens at pressures that stress the material beyond its yield point and at thermal loads that give rise to creep. The consideration of both traditional and advanced topics ensures that the book will be of value for a broad spectrum of readers, including students in postgraduate, and doctoral programs and established researchers and design engineers. The relations provided will serve as a sound basis for the design of products that are safe, technologically sophisticated, and compliant with standards and codes and for the development of innovative applications.

  14. Relationship of pressure to temperature rise in overfilled cylinders

    International Nuclear Information System (INIS)

    Barber, E.J.

    1979-01-01

    Mild steel pressure vessels containing uranium hexafluoride are heated in 96-inch diameter autoclaves to allow the feed material to enter the gaseous diffusion process equipment for enrichment in the uranium 235 isotope. For purposes of safety analysis it is necessary to establish the ability of the instrumentation to shut off the steam supply to the autoclave prior to cylinder rupture if the cylinder has been overfilled. To make this determination requires estimates of the rate of change of pressure with respect to change of temperature at constant volume as a function of the temperature at which the ullage disappears. The paper presents the calculations for the estimation of this rate of change for liquid uranium hexafluoride using the ratio of the coefficients of expansion and compressibility using empirical liquid density data and the Eyring equation of state for liquids. 5 figs. (MB)

  15. OPAL Forward Calorimeter (half cylinder with lead scintillator)

    CERN Multimedia

    1 half cylinder piece is available for loan. The OPAL forward Detector Calorimeter was made in 4 half cylindrical pieces. Two full cylinders were placed round the LEP beam pipe about 3m downstream of the interaction point. The detector was used primarily to measure the luminosity of LEP (rate of interactions) and also to trigger on 2-photon events. In addition it formed an essential part of the detector coverage which OPAL needed to carry out searches for new particles such as the Higgs boson. The detector is made of scintillators sandwiched between lead sheets. The light from the scintillators passes via bars of wavelength shifter and light guides on its way to be measured by photomultipliers. There is a layer of gas filled tube chambers within the calorimeter. These provide a measure of the position of the particles interacting in the calorimeter.

  16. Integrated two-cylinder liquid piston Stirling engine

    International Nuclear Information System (INIS)

    Yang, Ning; Rickard, Robert; Pluckter, Kevin; Sulchek, Todd

    2014-01-01

    Heat engines utilizing the Stirling cycle may run on low temperature differentials with the capacity to function at high efficiency due to their near-reversible operation. However, current approaches to building Stirling engines are laborious and costly. Typically the components are assembled by hand and additional components require a corresponding increase in manufacturing complexity, akin to electronics before the integrated circuit. We present a simple and integrated approach to fabricating Stirling engines with precisely designed cylinders. We utilize computer aided design and one-step, planar machining to form all components of the engine. The engine utilizes liquid pistons and displacers to harness useful work from heat absorption and rejection. As a proof of principle of the integrated design, a two-cylinder engine is produced and characterized and liquid pumping is demonstrated.

  17. Nonideal ultrathin mantle cloak for electrically large conducting cylinders.

    Science.gov (United States)

    Liu, Shuo; Zhang, Hao Chi; Xu, He-Xiu; Cui, Tie Jun

    2014-09-01

    Based on the concept of the scattering cancellation technique, we propose a nonideal ultrathin mantle cloak that can efficiently suppress the total scattering cross sections of an electrically large conducting cylinder (over one free-space wavelength). The cloaking mechanism is investigated in depth based on the Mie scattering theory and is simultaneously interpreted from the perspective of far-field bistatic scattering and near-field distributions. We remark that, unlike the perfect transformation-optics-based cloak, this nonideal cloaking technique is mainly designed to minimize simultaneously several scattering multipoles of a relatively large geometry around considerably broad bandwidth. Numerical simulations and experimental results show that the antiscattering ability of the metasurface gives rise to excellent total scattering reduction of the electrically large cylinder and remarkable electric-field restoration around the cloak. The outstanding cloaking performance together with the good features of and ultralow profile, flexibility, and easy fabrication predict promising applications in the microwave frequencies.

  18. Kinematic Parameters Of Rotary Transmission With Hydraulic Cylinders

    Directory of Open Access Journals (Sweden)

    Blaschuk Mikhail

    2017-01-01

    Full Text Available The issue of designing drives, which provide low frequency (max. 1 rotation per minute rotation with a big moment (min 1 MN m of large technical bodies utilized in restricted spaces, is a complex and contradictory one. The drives of geokhod propeller, rotor actuators of tunneling machines with overload protection, as well as actuators of other machinery meeting aforementioned requirements are examples of such machines. The paper considers mathematical model developed by the authors which determines the relation of design factors of transmission tooled with hydraulic cylinders to kinematic parameters of output element movement. The paper also provides description of methods to determine pumping unit efficiency for rotary transmission tooled with hydraulic cylinders.

  19. Angular Momentum Transport in Turbulent Flow between Independently Rotating Cylinders

    International Nuclear Information System (INIS)

    Paoletti, M. S.; Lathrop, D. P.

    2011-01-01

    We present measurements of the angular momentum flux (torque) in Taylor-Couette flow of water between independently rotating cylinders for all regions of the (Ω 1 , Ω 2 ) parameter space at high Reynolds numbers, where Ω 1 (Ω 2 ) is the inner (outer) cylinder angular velocity. We find that the Rossby number Ro=(Ω 1 -Ω 2 )/Ω 2 fully determines the state and torque G as compared to G(Ro=∞)≡G ∞ . The ratio G/G ∞ is a linear function of Ro -1 in four sections of the parameter space. For flows with radially increasing angular momentum, our measured torques greatly exceed those of previous experiments [Ji et al., Nature (London), 444, 343 (2006)], but agree with the analysis of Richard and Zahn [Astron. Astrophys. 347, 734 (1999)].

  20. Rotational oscillations of a cylinder in cross-flow

    International Nuclear Information System (INIS)

    Al-Mdallal, Q.M.; Kocabiyik, S.

    2005-01-01

    The laminar unsteady periodic flow motion found in the wake of rotationally oscillating circular cylinder is investigated numerically at a Reynolds number of 855 over a wide range of oscillation amplitude and frequency ratio. The governing Navier-Stokes equations are integrated to determine the flow field structure for large values of the time using an accurate spectral finite difference method, but with the boundary vorticity calculated using global vorticity conditions rather than local finite-difference approximations. The lock on phenomenon has been predicted and its effect on the flow hydrodynamics has been determined. The numerical scheme is verified by applying it to the special case of a steadily rotating cylinder (no forced oscillations) and good qualitative agreements are found. (author)

  1. Development of control system of coating of rod hydraulic cylinders

    Science.gov (United States)

    Aizhambaeva, S. Zh; Maximova, A. V.

    2018-01-01

    In this article, requirements to materials of hydraulic cylinders and methods of eliminating the main factors affecting the quality of the applied coatings rod hydraulic cylinders. The chromium plating process - one of ways of increase of anti-friction properties of coatings rods, stability to the wear and corrosion. The article gives description of differences of the stand-speed chromium plating process from other types of chromium plating that determines a conclusion about cutting time of chromium plating process. Conducting the analysis of technological equipment suggested addressing the modernization of high-speed chromium plating processes by automation and mechanization. Control system developed by design of schematic block diagram of a modernized and stand-speed chromium plating process.

  2. Lubrication of ceramics in ring/cylinder applications

    International Nuclear Information System (INIS)

    Gaydos, P.A.; Dufrane, K.F.

    1989-01-01

    In support of efforts to apply ceramics to advanced heat engines, a study was performed of the wear mechanisms of ceramics at the ring/cylinder interface. A laboratory apparatus was constructed to reproduce most of the conditions of an actual engine but used easily prepared ring and cylinder specimens to facilitate their fabrication. Plasma-sprayed coatings of Cr 2 O 3 and hypersonic flame-sprayed coatings of cobalt-bonded WC performed particularly well as ring coatings. Similar performance was obtained with these coatings operating against SiC, Si 3 N 4 , SiC whisker-reinforced Al 2 O 3 and Cr 2 O 2 coatings. The study demonstrated the critical need for lubrication and evaluated the performance of two available lubricants

  3. Grinding efficiency improvement of hydraulic cylinders parts for mining equipment

    Directory of Open Access Journals (Sweden)

    Korotkov Aleksandr

    2017-01-01

    Full Text Available The aim of the article is to find out ways to improve parts treatment and components of mining equipment on the example of hydraulic cylinders parts, used as pillars for mine roof supports, and other actuator mechanisms. In the course of the research work methods of machine retaining devices design were used, the scientific approaches for the selection of progressive grinding schemes were applied; theoretical and practical experience in the design and production of new constructions of grinding tools was used. As a result of this work it became possible to create a progressive construction of a machine retaining device for grinding of large parts of hydraulic cylinders, to apply an effective scheme of rotary abrasive treatment, to create and implement new design of grinding tools by means of grains with controllable shape and orientation. Implementation of the results obtained in practice will improve the quality and performance of repairing and manufacturing of mining equipment.

  4. Experimental investigation of axially aligned flow past spinning cylinders

    Science.gov (United States)

    Carlucci, Pasquale; Buckley, Liam; Mehmedagic, Igbal; Carlucci, Donald; Thangam, Siva

    2016-11-01

    Experimental and numerical results of ongoing subsonic investigations of the flow field about axially aligned spinning cylinders with variable inter-cylinder spacing are presented. The experimental design is capable of investigating wake dynamics of the modeled system up to a Reynolds Number of 300,000 and rotation numbers up to 2. The experimental results are used to validate and confirm numerical simulations with and without the effects of swirl. The focus of the overall effort is an understanding of the dynamics of multi-body problems in a flow field, as such we relate the ongoing effort to previous studies by both the authors and the community at large and our ongoing work in developing accurate plant models for use in engineering analysis and design. Funded in part by U. S. Army ARDEC, Picatinny Arsenal, NJ.

  5. Flow Features of Three Side-by-side Circular Cylinders at Low Reynolds Number

    Directory of Open Access Journals (Sweden)

    Liu Junkao

    2016-01-01

    Full Text Available In order to study the fluctuation of kinetic parameter of cylinder matrix in incompressible stationary flow, the flow fluid around three side-by-side circular cylinders are simulated using Immersed Boundary–Lattice Boltzmann method (IB-LBM. Drag and lift force of the three cylinders are investigated as the interval between each cylinder varied from zero to five times of the cylinder diameter. Five flow patterns are defined according to the vortices structure in the downstream of the cylinders. Power spectrum analysis of lift force is developed to explain the vortex patterns. Through the research, we find the strength and phase of the gap flow play an important role in the vortex formatting process. The vortices shedding from different cylinders neutralize and combine in the near wake, contributing a lot to the variation of forces.

  6. Cracked lifting lug welds on ten-ton UF{sub 6} cylinders

    Energy Technology Data Exchange (ETDEWEB)

    Dorning, R.E. [Martin Marietta Energy Systems, Inc., Piketon, OH (United States)

    1991-12-31

    Ten-ton, Type 48X, UF{sub 6} cylinders are used at the Portsmouth Gaseous Diffusion Plant to withdraw enriched uranium hexafluoride from the cascade, transfer enriched uranium hexafluoride to customer cylinders, and feed enriched product to the cascade. To accomplish these activities, the cylinders are lifted by cranes and straddle carriers which engage the cylinder lifting lugs. In August of 1988, weld cracks on two lifting lugs were discovered during preparation to lift a cylinder. The cylinder was rejected and tagged out, and an investigating committee formed to determine the cause of cracking and recommend remedial actions. Further investigation revealed the problem may be general to this class of cylinder in this use cycle. This paper discusses the actions taken at the Portsmouth site to deal with the cracked lifting lug weld problem. The actions include inspection activities, interim corrective actions, metallurgical evaluation of cracked welds, weld repairs, and current monitoring/inspection program.

  7. Effect of catalytic cylinders on autothermal reforming of methane for hydrogen production in a microchamber reactor.

    Science.gov (United States)

    Yan, Yunfei; Guo, Hongliang; Zhang, Li; Zhu, Junchen; Yang, Zhongqing; Tang, Qiang; Ji, Xin

    2014-01-01

    A new multicylinder microchamber reactor is designed on autothermal reforming of methane for hydrogen production, and its performance and thermal behavior, that is, based on the reaction mechanism, is numerically investigated by varying the cylinder radius, cylinder spacing, and cylinder layout. The results show that larger cylinder radius can promote reforming reaction; the mass fraction of methane decreased from 26% to 21% with cylinder radius from 0.25 mm to 0.75 mm; compact cylinder spacing corresponds to more catalytic surface and the time to steady state is decreased from 40 s to 20 s; alteration of staggered and aligned cylinder layout at constant inlet flow rates does not result in significant difference in reactor performance and it can be neglected. The results provide an indication and optimize performance of reactor; it achieves higher conversion compared with other reforming reactors.

  8. Effect of Catalytic Cylinders on Autothermal Reforming of Methane for Hydrogen Production in a Microchamber Reactor

    Directory of Open Access Journals (Sweden)

    Yunfei Yan

    2014-01-01

    Full Text Available A new multicylinder microchamber reactor is designed on autothermal reforming of methane for hydrogen production, and its performance and thermal behavior, that is, based on the reaction mechanism, is numerically investigated by varying the cylinder radius, cylinder spacing, and cylinder layout. The results show that larger cylinder radius can promote reforming reaction; the mass fraction of methane decreased from 26% to 21% with cylinder radius from 0.25 mm to 0.75 mm; compact cylinder spacing corresponds to more catalytic surface and the time to steady state is decreased from 40 s to 20 s; alteration of staggered and aligned cylinder layout at constant inlet flow rates does not result in significant difference in reactor performance and it can be neglected. The results provide an indication and optimize performance of reactor; it achieves higher conversion compared with other reforming reactors.

  9. Research on torsional vibration modelling and control of printing cylinder based on particle swarm optimization

    Science.gov (United States)

    Wang, Y. M.; Xu, W. C.; Wu, S. Q.; Chai, C. W.; Liu, X.; Wang, S. H.

    2018-03-01

    The torsional oscillation is the dominant vibration form for the impression cylinder of printing machine (printing cylinder for short), directly restricting the printing speed up and reducing the quality of the prints. In order to reduce torsional vibration, the active control method for the printing cylinder is obtained. Taking the excitation force and moment from the cylinder gap and gripper teeth open & closing cam mechanism as variable parameters, authors establish the dynamic mathematical model of torsional vibration for the printing cylinder. The torsional active control method is based on Particle Swarm Optimization(PSO) algorithm to optimize input parameters for the serve motor. Furthermore, the input torque of the printing cylinder is optimized, and then compared with the numerical simulation results. The conclusions are that torsional vibration active control based on PSO is an availability method to the torsional vibration of printing cylinder.

  10. On the heat transfer of enhancement condensation of vapor over the surface of an axisymmetric cylinder

    International Nuclear Information System (INIS)

    Xiou, W.J.; Ru, Y.A.; Mo, C.S.; Yi, H.S.

    1987-01-01

    The heat transfer of enhancement condensation of the vapor over the surface of an axisymmetric cylinder has been first studied theoretically in this paper. The problems of an axisymmetric cylinder are transformed into plate problems. The effects of some parameters on heat transfer coefficients of the vapor condensation over the surface of an axisymmetric cylinder have been discussed here. The heat transfer of the vapor condensation over an elliptical cylinder and an axisymmetric wing-shape cylinder has compared with the heat transfer of the vapor condensation over a tube surface. The conclusion is that the heat transfer of the vapor condensation over an elliptical cylinder and an axisymmetric wing-shape cylinder is greater than that over tubes

  11. Structure of the Cpf1 endonuclease R-loop complex after target DNA cleavage.

    Science.gov (United States)

    Stella, Stefano; Alcón, Pablo; Montoya, Guillermo

    2017-06-22

    Cpf1 is an RNA-guided endonuclease that is emerging as a powerful genome-editing tool. Here we provide insight into its DNA-targeting mechanism by determining the structure of Francisella novicida Cpf1 with the triple-stranded R-loop generated after DNA cleavage. The structure reveals the machinery involved in DNA unwinding to form a CRISPR RNA (crRNA)-DNA hybrid and a displaced DNA strand. The protospacer adjacent motif (PAM) is recognized by the PAM-interacting domain. The loop-lysine helix-loop motif in this domain contains three conserved lysine residues that are inserted in a dentate manner into the double-stranded DNA. Unzipping of the double-stranded DNA occurs in a cleft arranged by acidic and hydrophobic residues facilitating the crRNA-DNA hybrid formation. The PAM single-stranded DNA is funnelled towards the nuclease site through a mixed hydrophobic and basic cavity. In this catalytic conformation, the PAM-interacting domain and the helix-loop-helix motif in the REC1 domain adopt a 'rail' shape and 'flap-on' conformations, respectively, channelling the PAM strand into the cavity. A steric barrier between the RuvC-II and REC1 domains forms the 'septum', separating the displaced PAM strand and the crRNA-DNA hybrid, avoiding DNA re-annealing. Mutations in key residues reveal a mechanism linking the PAM and DNA nuclease sites. Analysis of the Cpf1 structures proposes a singular working model of RNA-guided DNA cleavage, suggesting new avenues for redesign of Cpf1.

  12. DESIGN OF THE FRONT CYLINDER TOOL FOR MILLINGHELICAL PUMP ROTORS

    Directory of Open Access Journals (Sweden)

    MORARESCU Ana

    2015-06-01

    Full Text Available The paper advances an algorithm for profiling the primary surface of a cylinder tool based on the substitution circle families. The composite profile of the worms in a helical pump is divided into zones of well defined shapes. By employing the AutoCAD program the worm gearing line can be plotted by a succession of points as well as the shape of axial –cross section of the tool.

  13. DESIGN OF THE FRONT CYLINDER TOOL FOR MILLINGHELICAL PUMP ROTORS

    OpenAIRE

    MORARESCU Ana

    2015-01-01

    The paper advances an algorithm for profiling the primary surface of a cylinder tool based on the substitution circle families. The composite profile of the worms in a helical pump is divided into zones of well defined shapes. By employing the AutoCAD program the worm gearing line can be plotted by a succession of points as well as the shape of axial –cross section of the tool.

  14. Detection of Buried Inhomogeneous Elliptic Cylinders by a Memetic Algorithm

    OpenAIRE

    Caorsi, Salvatore; Massa, Andrea; Pastorino, Matteo; Raffetto, Mirco; Randazzo, Andrea

    2003-01-01

    The application of a global optimization procedure to the detection of buried inhomogeneities is studied in the present paper. The object inhomogeneities are schematized as multilayer infinite dielectric cylinders with elliptic cross sections. An efficient recursive analytical procedure is used for the forward scattering computation. A functional is constructed in which the field is expressed in series solution of Mathieu functions. Starting by the input scattered data, the iterative minimiza...

  15. Laminar vortex shedding behind a cooled circular cylinder

    Czech Academy of Sciences Publication Activity Database

    Trávníček, Zdeněk; Wang, A. B.; Tu, W.Y.

    2014-01-01

    Roč. 55, č. 2 (2014), s. 1-12 ISSN 0723-4864 R&D Projects: GA ČR GA14-08888S Institutional support: RVO:61388998 Keywords : vortex shedding * cooled circular cylinder * thermal effect Subject RIV: JU - Aeronautics, Aerodynamics, Aircrafts Impact factor: 1.670, year: 2014 http://link.springer.com/journal/348/55/2/page/1

  16. Structural Design of Two-Cylinder Single Overhead Camshaft

    Science.gov (United States)

    Zhao, Yuxia; Zhang, Kangsheng; Di, Jiejian

    2018-01-01

    Due to the higher performance demand, the camshaft is the key driving part in the engine. Because it is eccentric circular section part, it is very difficult to design and manufacture this kind of axial parts. Take two-cylinder single overhead camshaft for an example, the entire process of camshaft design is analyzed. The practice has proved that the method has simple, flexible and efficient advantages, and it can greatly shorten the design of artificial computing time.

  17. Feasibility study of electromechanical cylinder drivetrain for offshore mechatronic systems

    DEFF Research Database (Denmark)

    Hagen, D.; Pawlus, W.; Ebbesen, M. K.

    2017-01-01

    Currently, there is an increasing focus on the environmental impact and energy consumption of the oil and gas industry. In offshore drilling equipment, electric motors tend to replace traditionally used hydraulic motors, especially in rotational motion control applications. However, force densities...... cylinder drivetrain. The simulation results are analyzed and discussed together with a literature study regarding advantages and disadvantages of the proposed solution considering the design criteria of offshore drilling equipment. It is concluded that the selected drivetrain can only satisfy the static...

  18. The videopulse scattering in inhomogeneous media containing conductive cylinder objects

    OpenAIRE

    Varianytsia-Roshchupkina, Liudmyla A.

    2003-01-01

    The results of the computer simulation of videopulse scattering on the conductive cylinder objects buried in homogeneous media are presented in this work. The finite difference time domain method (FDTD) and Mur's absorbing boundary conditions of second order were used to regularize the problem. The analysis and the comparison of the scattered electromagnetic fields obtained at different dielectric parameters of the media and different sizes of the conductive objects were carried out.

  19. Properties of Sub-wavelength Resonances in Metamaterial Cylinders

    DEFF Research Database (Denmark)

    Arslanagic, Samel; Clausen, N.C.J.; Pedersen, R.R.

    2008-01-01

    The analytical solution for the canonical configuration with electric line source illumination of concentric metamaterial cylinders is employed to study the properties of the observed sub-wavelength resonances. The near- and far-field distributions, the frequency and geometry bandwidths, and the ......, and the line source impedance are investigated for varying electromagnetic and geometrical parameters. The results of this study are of importance for metamaterial-based miniaturization of antennas....

  20. Filament winding cylinders. III - Selection of the process variables

    Science.gov (United States)

    Lee, Soo-Yong; Springer, George S.

    1990-01-01

    By using the Lee-Springer filament winding model temperatures, degrees of cure, viscosities, stresses, strains, fiber tensions, fiber motions, and void diameters were calculated in graphite-epoxy composite cylinders during the winding and subsequent curing. The results demonstrate the type of information which can be generated by the model. It is shown, in reference to these results, how the model, and the corresponding WINDTHICK code, can be used to select the appropriate process variables.

  1. Multi-black-hole configurations on the cylinder

    International Nuclear Information System (INIS)

    Dias, Oscar J. C.; Harmark, Troels; Obers, Niels A.; Myers, Robert C.

    2007-01-01

    We construct the metric of new multi-black-hole configurations on a d-dimensional cylinder R d-1 xS 1 , in the limit of small total mass (or equivalently in the limit of a large cylinder). These solutions are valid to first order in the total mass and describe configurations with several small black holes located at different points along the circle direction of the cylinder. We explain that a static configuration of black holes is required to be in equilibrium such that the external force on each black hole is zero, and we examine the resulting conditions. The first-order corrected thermodynamics of the solutions is obtained and a Newtonian interpretation of it is given. We then study the consequences of the multi-black-hole configurations for the phase structure of static Kaluza-Klein black holes and show that our new solutions imply continuous nonuniqueness in the phase diagram. The new multi-black-hole configurations raise the question of existence of new nonuniform black strings. Finally, a further analysis of the three-black-hole configuration suggests the possibility of a new class of static lumpy black holes in Kaluza-Klein space

  2. Evaluation of Analysis Techniques for Fluted-Core Sandwich Cylinders

    Science.gov (United States)

    Lovejoy, Andrew E.; Schultz, Marc R.

    2012-01-01

    Buckling-critical launch-vehicle structures require structural concepts that have high bending stiffness and low mass. Fluted-core, also known as truss-core, sandwich construction is one such concept. In an effort to identify an analysis method appropriate for the preliminary design of fluted-core cylinders, the current paper presents and compares results from several analysis techniques applied to a specific composite fluted-core test article. The analysis techniques are evaluated in terms of their ease of use and for their appropriateness at certain stages throughout a design analysis cycle (DAC). Current analysis techniques that provide accurate determination of the global buckling load are not readily applicable early in the DAC, such as during preliminary design, because they are too costly to run. An analytical approach that neglects transverse-shear deformation is easily applied during preliminary design, but the lack of transverse-shear deformation results in global buckling load predictions that are significantly higher than those from more detailed analysis methods. The current state of the art is either too complex to be applied for preliminary design, or is incapable of the accuracy required to determine global buckling loads for fluted-core cylinders. Therefore, it is necessary to develop an analytical method for calculating global buckling loads of fluted-core cylinders that includes transverse-shear deformations, and that can be easily incorporated in preliminary design.

  3. Natural Gas Vehicle Cylinder Safety, Training and Inspection Project

    Energy Technology Data Exchange (ETDEWEB)

    Hank Seiff

    2008-12-31

    Under the auspices of the National Energy Technology Laboratory and the US Department of Energy, the Clean Vehicle Education Foundation conducted a three-year program to increase the understanding of the safe and proper use and maintenance of vehicular compressed natural gas (CNG) fuel systems. High-pressure fuel systems require periodic inspection and maintenance to insure safe and proper operation. The project addressed the needs of CNG fuel containers (cylinders) and associated high-pressure fuel system components related to existing law, codes and standards (C&S), available training and inspection programs, and assured coordination among vehicle users, public safety officials, fueling station operators and training providers. The program included a public and industry awareness campaign, establishment and administration of a cylinder inspector certification training scholarship program, evaluation of current safety training and testing practices, monitoring and investigation of CNG vehicle incidents, evaluation of a cylinder recertification program and the migration of CNG vehicle safety knowledge to the nascent hydrogen vehicle community.

  4. Inertial rise of a meniscus on a vertical cylinder

    KAUST Repository

    O’Kiely, Doireann

    2015-03-03

    © © 2015 Cambridge University PressA. We consider the inertia-dominated rise of a meniscus around a vertical circular cylinder. Previous experiments and scaling analysis suggest that the height of the meniscus, h-{m}, grows with the time following the initiation of rise, t, like h-{m}\\\\propto t^{1/2}. This is in contrast to the rise on a vertical plate, which obeys the classic capillary-inertia scaling h-{m}\\\\propto t^{2/3}. We highlight a subtlety in the scaling analysis that yielded h-{m}\\\\propto t^{1/2} and investigate the consequences of this subtlety. We develop a potential flow model of the dynamic problem, which we solve using the finite element method. Our numerical results agree well with previous experiments but suggest that the correct early time behaviour is, in fact, h-{m}\\\\propto t^{2/3}. Furthermore, we show that at intermediate times the dynamic rise of the meniscus is governed by two parameters: the contact angle and the cylinder radius measured relative to the capillary length scale, t^{2/3}. This result allows us to collapse previous experimental results with different cylinder radii (but similar static contact angles) onto a single master curve.

  5. Research on a lubricating grease print process for cylindrical cylinder

    Science.gov (United States)

    Yang, Liu; Zhang, Xuan; Wang, XianYan; Tan, XiaoYan

    2017-09-01

    In vehicle braking system and clutch system of transmission, there is always a kind of cylindrical component dose reciprocating motion. The main working method is the reciprocating motion between the rubber sealing parts and cylindrical parts, the main factor affects the service life of the product is the lubricating performance of the moving parts. So the lubricating performance between cylinders and rubber sealing rings is particularly important, same as the quality of the grease applies on the surface of the surface of cylinder. Traditional method of manually applying grease has some defects such as applying unevenly, applying tools like brush and cloth easily falls off and affect the cleanness of products, contact skin easily cause allergy, waste grease due to the uncontrollable of grease quantity using in applying, low efficiency of manual operation. An automatic, quantitative and high pressure applying equipment is introduced in this document to replace the traditional manually applying method, which can guarantee the applying quality of the grease which are painted on the surface of cylinder and bring economic benefits to the company.

  6. SIMULATION OF SCOURING AROUND A VERTICAL CYLINDER DUE TO TSUNAMI

    Directory of Open Access Journals (Sweden)

    Kuswandi

    2017-06-01

    Full Text Available Local scour due to tsunami is damaging especially on shallow foundation. Although relatively in a short duration, tsunami attack may scour material around buildings that led to destruction. A number of formulae on local scouring due to flood and tsunami have been available. The local scouring pattern and depth produced by tsunami may be affected by tsunami duration and tsunami surge Froude number and hence different to that resulted by flood which normally have much longer duration and lower Froude number. The research used a relatively short flume to create short duration tsunami surge that run-up on 1:20 beach slope and hit a vertical cylinder on land. Both the pattern and the depth of local scouring around the cylinder were observed and the results were compared with similar research but with different tsunami surge characteristic. It was shown that the maximum scour depth was significantly deeper than the final scour depth. When compared with other experimental study of local scour due to tsunami, the present local scour maximum depth seemed to be slightly less. This could have been caused by the relatively short duration of the present experiment. It was also found that the sidewall effect was insignificant when the ratio of cylinder diameter to the flume width was less then approximately 0.15.

  7. Computational and Experimental Investigations of Flow past Spinning Cylinders

    Science.gov (United States)

    Mehmedagic, Igbal; Buckley, Liam; Carlucci, Pasquale; Carlucci, Donald; Aljalis, Elias; Thangam, Siva; Stevens-Ardec Collaboration

    2012-11-01

    An anisotropic two-equation Reynolds-stress model is developed by considering the modifications to the energy spectrum and through invariance based scaling. In this approach the effect of rotation is used to modify the energy spectrum, while the influence of swirl is modeled based on scaling laws. The resulting generalized model is validated for benchmark turbulent flows with swirl and curvature. The time-averaged equations of motion and energy are solved using the modeled form of transport equations for the turbulence kinetic energy and the scalar form of turbulence dissipation with an efficient finite-volume algorithm. Computations for flow past an axially rotating cylinder with a free-spinning base are performed along with experiments for a range of spin rates and free stream flow conditions. A subsonic wind tunnel with a forward-sting mounted spinning cylinder is used for experiments. The experimental results of Carlucci & Thangam (2001) are used to benchmark flow over spinning cylinders. The data is extended to munitions spinning in the wake of other munitions and applications involving the design of projectiles are discussed. This work was funded in part by U. S. Army ARDEC.

  8. Performance Evaluation of Rotating Cylinder Type Coffee Bean Roaster

    Directory of Open Access Journals (Sweden)

    Sutarsi

    2010-04-01

    Full Text Available One strategy attempts to reduce dependence on primary commodity markets are overseas market expansion and development of secondary products. In the secondary product processing coffee beans is required of supporting equipment to facilitate these efforts. Research Center for Indonesian Coffee and Cocoa has developed coffee bean roaster. However, there are still many people who do not know about the technical aspects of roaster machine type of rotating cylinder so that more people use traditional ways to roast coffee beans. In order for the benefits of this machine is better known society it is necessary to study on the technical aspects. The purpose of this research is to evaluate the technical performance of the coffee beans roaster machine type of rotating cylinder. These include the technical aspects of work capacity of the machine, roasting technical efficiency, fuel requirements, and power requirements of using roaster machine. Research methods are including data collection, calculation and analysis. The results showed that the roaster machine type of a rotating cylinder has capacity of 12.3 kg/hour. Roasting efficiency is 80%. Fuel consumption is 0.6 kg. The calculated amount of the used power of current measurement is the average of 0.616 kW.

  9. Natural convection heat transfer on two horizontal cylinders in liquid sodium

    Energy Technology Data Exchange (ETDEWEB)

    Hata, K.; Shiotsu, M.; Takeuchi, Y. [Institute of Atomic Energy, Kyoto Univ. (Japan)] [and others

    1995-09-01

    Natural convection heat transfer on two horizontal 7.6 mm diameter test cylinders assembled with the ratio of the distance between each cylinder axis to the cylinder diameter, S/D, of 2 in liquid sodium was studied experimentally and theoretically. The heat transfer coefficients on the cylinder surface due to the same heat inputs ranging from 1.0 X 10{sup 7} to 1.0 x 10{sup 9} W/m{sup 3} were obtained experimentally for various setting angeles, {gamma}, between vertical direction and the plane including both of these cylinder axis over the range of zero to 90{degrees}. Theoretical equations for laminar natural convection heat transfer from the two horizontal cylinders were numerically solved for the same conditions as the experimental ones considering the temperature dependence of thermophysical properties concerned. The average Nusselt numbers, Nu, values on the Nu versus modified Rayleigh number, R{sub f}, graph. The experimental values of Nu for the upper cylinder are about 20% lower than those for the lower cylinder at {gamma} = 0{degrees} for the range of R{sub f} tested here. The value of Nu for the upper cylinder becomes higher and approaches that for the lower cylinder with the increase in {gamma} over range of 0 to 90{degrees}. The values of Nu for the lower cylinder at each {gamma} are almost in agreement with those for a single cylinder. The theoretical values of Nu on two cylinders except those for R{sub f}<4 at {gamma} = 0{degrees} are in agreement with the experimental data at each {gamma} with the deviations less than 15%. Correlations for Nu on the upper and lower cylinders were obtained as functions of S/D and {gamma} based n the theoretical solutions for the S/D ranged over 1.5 to 4.0.

  10. Carboplatin enhances the production and persistence of radiation-induced DNA single-strand breaks

    International Nuclear Information System (INIS)

    Yang, L.; Douple, E.B.; O'Hara, J.A.; Wang, H.J.

    1995-01-01

    Fluorometric analysis of DNA unwinding and alkaline elution were used to investigate the production and persistence of DNA single-strand breaks (SSBs) in Chinese hamster V79 and xrs-5 cells treated with the chemotherapeutic agent carboplatin in combination with radiation. Carboplatin was administered to cells before irradiation in hypoxic conditions, or the drug was added immediately after irradiation during the postirradiation recovery period in air. The results of DNA unwinding studies suggest that carboplatin enhances the production of radiation-induced SSBs in hypoxic V79 cells and xrs-5 cells by a factor of 1.86 and 1.83, respectively, when combined with radiation compared to the SSBs produced by irradiation alone. Carboplatin alone did not produce a measureable number of SSBs. Alkaline elution profiles also indicated that the rate of elution of SSBs was higher in cells treated with the carboplatin is present after irradiation and during the postirradiation recovery period, the rejoining of radiation-induced SSBs by a factor of 1.46 in V79 cells with 20 Gy irradiation and by a factor of 2.02 in xrs-5 cells with 20 Gy irradiation. When carboplatin is present after irradiation and during the postirradiation recovery period, the rejoining of radiation-induced SSBs is inhibited during this postirradiation incubation period (radiopotentiation) with a relative inhibition factor at 1 h postirradiation of 1.25 in V79 cells and 1.15 in xrs-5 cells. An increased production and persistence of SSBs resulting from the interaction of carboplatin with radiation may be an important step in the mechanism responsible for the potentiated cell killing previously from studies in animal tumors and in cultured cells. 31 refs., 7 figs

  11. Helical cylinders or multicompartment cylinders through the solution assembly of charged block copolymers with multivalent organic counterions

    Science.gov (United States)

    Pochan, Darrin; Zhong, Sheng; Cui, Honggang; Chen, Zhiyun; Wooley, Karen

    2008-03-01

    By manipulating the interaction of charged block copolymer hydrophilic corona blocks with multivalent organic counterions, and controlling the kinetics of block copolymer solution self-assembly, desired micelle geometries can be formed. Specifically, polyacrylic acid-b-polymethylacrylate-b-polystyrene amphiphilic triblock copolymers were studied in water/THF solvent mixtures with organic multiamines as counterions. By manipulating block copolymer and solvent composition, different micelle geometries were formed. However, by altering the chemical structure and/or concentration of the multiamine counterions, as well as the kinetic pathway through which the molecules are assembled, complex nanostructures were formed. An example of nanostructure from kinetic control includes spherical micelles that can be controllably assembled into 1-d multicompartment cylinders. Examples of nanostructure from control of the type and amount of multivalent organic counterion added are helical cylinder superstructures many micrometers in length. The system has been investigated by means of cryogenic transmission electron microscopy (cryo-TEM) and small angle neutron scattering (SANS).

  12. SPACETRAN, Radiation Leakage from Cylinder with ANISN Flux Calculation

    International Nuclear Information System (INIS)

    Cramer, S.N.; Solomito, M.

    1974-01-01

    1 - Nature of physical problem solved: SPACETRAN is designed to calculate the energy-dependent total flux or some proportional quantity such as kerma, due to the radiation leakage from the surface of a right-circular cylinder at detector positions located at arbitrary distances from the surface. The assumptions are made that the radiation emerging from the finite cylinder has no spatial dependence and that a vacuum surrounds the cylinder. 2 - Method of solution: There are three versions of the program in the code package. SPACETRAN-I uses the surface angular fluxes calculated by the discrete ordinates SN code ANISN, as input. SPACETRAN-II assumes that the surface angular flux for all energies can be represented as a function (Cos(PHI))**N, where PHI is the angle between surface outward normal and radiation direction, and N is an integer specified by the user. For both versions the energy group structure and the number and location of detectors is arbitrary. The flux (or response function) for a given energy group at some detection point is computed by summing the contributions from each surface area element over the entire surface. The surface area elements are defined by input data. SPACETRAN-III uses surface angular fluxes from DOT-3. SPACETRAN-I handles contributions either from a cylinder 'end' or 'side', so the total contributions must be obtained by adding the results of separate end and side runs. ANISN angular fluxes are specified for discrete directions. In general, the direction between the detector and contributing area will not exactly coincide with one of these discrete directions. In this case, the ANISN angular flux for the 'closest' discrete direction is used to approximate the contribution to the detector. SPACETRAN-II handles contributions from both the side and end of a cylinder in a single run. Since the assumed angular distribution is specified by a continuous function, it is not necessary to perform the angle selection described above. For

  13. A nonlinear model for a towed flexible cylinder

    Science.gov (United States)

    Kheiri, M.; Païdoussis, M. P.; Amabili, M.

    2013-04-01

    In this paper, a weakly nonlinear equation of motion is derived for the dynamics of a towed, neutrally buoyant flexible slender cylinder. The cylinder is terminated by end-pieces at its two ends and is fastened via a massless towrope to a support rigidly fixed upstream. The motions are considered to take place in a horizontal plane. The equation of motion is obtained via Hamilton's principle after obtaining the Lagrangian of the system and the virtual work associated with the fluid dynamic forces. For convenience, the fluid-related forces are derived separately: inviscid hydrodynamic forces are modelled by an extension of Lighthill's slender-body work to third-order accuracy, and the viscous forces are derived to the same accuracy, by elaboration of Taylor's expressions. The Galerkin method is used to discretize the equation of motion with the free-free Euler-Bernoulli beam eigenfunctions, and the resulting set of first-order equations are solved numerically using a time-integration solver. Numerical results are obtained to illustrate the typical dynamical behaviour of a towed flexible cylinder, generally confirming experimental observations and linear theory predictions made in the past. Also, the effect of the towrope-length to cylinder-length ratio and the effect of the tail end-piece shape on the dynamics and stability of the system are investigated. The results confirm that for a towed flexible cylinder, if the tail end-piece is not blunt and the towrope not too short, both rigid-body and flexural instabilities may develop as the flow velocity is increased. The former occur at low flow velocities, in the form of oscillatory and then static instabilities, whereas the latter generally occur at higher flow velocities in the form of second- and then third-mode flutter. Moreover, it is found that the system becomes less stable and is subject to larger deformations if the towrope is longer. On the other hand, making the tail end-piece sufficiently blunt can

  14. Some Investigations of the General Instability of Stiffened Metal Cylinders VII : Stiffened Metal Cylinders Subjected to Combined Bending and Torsion

    Science.gov (United States)

    1943-01-01

    This report summarizes the work that has been carried on in the experimental investigation of the problem of the general instability of stiffened metal cylinders subjected to combined bending and torsion at the C.I.T. This part of the investigation included tests on 26 sheet-covered specimens. An interaction curve for the case of combined bending and torsion is presented. The results of tests of 17 specimens subjected to pure torsion are also given.

  15. 78 FR 55679 - High Pressure Steel Cylinders From the People's Republic of China; Rescission of the 2011-2013...

    Science.gov (United States)

    2013-09-11

    ... liquefied gas (``high pressure steel cylinders''). High pressure steel cylinders are fabricated of chrome... Cylinders From the People's Republic of China; Rescission of the 2011-2013 Antidumping Duty Administrative... antidumping duty order on high pressure steel cylinders from the People's Republic of China (``PRC'') for the...

  16. A computational study of drag reduction and vortex shedding suppression of flow past a square cylinder in presence of small control cylinders

    Science.gov (United States)

    Islam, Shams-Ul.; Manzoor, Raheela; Islam, Zia-Ul.; Kalsoom, Shazia; Ying, Zhou Chao

    2017-04-01

    This article presents a two-dimensional numerical study of the unsteady laminar flow from a square cylinder in presence of multiple small control cylinders. The cylinders are placed in an unconfined medium at low Reynolds numbers (Re = 100 and 160). Different flow phenomena are captured for the gap spacings (g = s/D, where s is the surface-to-surface distance between the main cylinder and small control cylinders and D is the size of the main cylinder) between 0.25 - 3 and angle of attack (θ) ranging from 300 to 1800. Numerical calculations are performed by using a lattice Boltzmann method. In this paper, the important flow physics of different observed flow patterns in terms of instantaneous vorticity contours visualization, time-trace analysis of drag and lift coefficients and power spectra analysis of lift coefficient are presented and discussed. Drag reduction and suppression of vortex shedding is also discussed in detail and compared with the available experimental and numerical results qualitatively as well as quantitatively. In addition, the mean drag coefficient, Strouhal number, root-mean-square values of the drag and lift coefficients are determined and compared with a single square cylinder without small control cylinders. We found that the drag is reduced 99.8% and 97.6% for (θ, g) = (300, 3) at Re = 100 and 160, respectively.

  17. Reynolds number effects on three-dimensional flow control over a square cylinder

    Science.gov (United States)

    Malekzadeh, S.; Mirzaee, I.; Pourmahmoud, N.

    2018-04-01

    In this article, the effects of Reynolds number on three-dimensional flow over a square cylinder with flow control are discussed at moderate Reynolds numbers, i.e. Re W = 200–1000 (based on the width of the square cylinder and the inlet flow velocity). The flow is controlled by a thin vertical plate placed upstream of the cylinder. The vorticity structures at different Reynolds numbers, turbulent kinetic energy, Reynolds stresses, and mean and fluctuating fluid forces on the square cylinder in the presence of the control plate are investigated in order to determine the characteristics of the transient flow regime at the wake region behind the square cylinder. The results show that the transitional process of the flow regime from laminar to turbulent in the wake region behind the square cylinder at Re W = 300–600 causes the pulsation phenomena to happen in the instantaneous lift signals of the square cylinder, and both of spanwise instability modes of A and B, as well as the dislocation phenomena are presented in the wake region behind the cylinder. It is also found that the mean and fluctuating fluid forces of the square cylinder in the presence of the control plate decrease in comparison to the single square cylinder, except for the rms drag coefficient at Re W = 300.

  18. Preliminary Concept of Operations for a Global Cylinder Identification and Monitoring System

    Energy Technology Data Exchange (ETDEWEB)

    Whitaker, J. M. [ORNL; White-Horton, J. L. [ORNL; Morgan, J. B. [InSolves Associates

    2013-08-01

    This report describes a preliminary concept of operations for a Global Cylinder Identification and Monitoring System that could improve the efficiency of the International Atomic Energy Agency (IAEA) in conducting its current inspection activities and could provide a capability to substantially increase its ability to detect credible diversion scenarios and undeclared production pathways involving UF6 cylinders. There exist concerns that a proliferant State with access to enrichment technology could obtain a cylinder containing natural or low-enriched uranium hexafluoride (UF6) and produce a significant quantity (SQ)1 of highly enriched uranium in as little as 30 days. The National Nuclear Security Administration (NNSA) through the Next Generation Safeguards Initiative sponsored a multi-laboratory team to develop an integrated system that provides for detecting scenarios involving 1) diverting an entire declared cylinder for enrichment at a clandestine facility, 2) misusing a declared cylinder at a safeguarded facility, and 3) using an undeclared cylinder at a safeguarded facility. An important objective in developing this integrated system was to improve the timeliness for detecting the cylinder diversion and undeclared production scenarios. Developing this preliminary concept required in-depth analyses of current operational and safeguards practices at conversion, enrichment, and fuel fabrication facilities. The analyses evaluated the processing, movement, and storage of cylinders at the facilities; the movement of cylinders between facilities (including cylinder fabrication); and the misuse of safeguarded facilities.

  19. Impact of vaginal cylinder diameter on outcomes following brachytherapy for early stage endometrial cancer.

    Science.gov (United States)

    Qian, Jack M; Stahl, John M; Young, Melissa R; Ratner, Elena; Damast, Shari

    2017-11-01

    To examine the outcomes (tolerability, toxicity, and recurrence) of vaginal brachytherapy (VBT) among endometrial cancer (EC) patients treated with small cylinder size. Patients with EC who received adjuvant VBT between September 2011 and December 2015 were reviewed. Patients were fitted with the largest vaginal cylinder they could comfortably accommodate, from 2.0-3.0 cm diameter. Small cylinders were defined as size 2.3 cm or less. Patient, tumor, or treatment characteristics were correlated with need for small cylinders. Treatment tolerability, measures of gastrointestinal (GI), genitourinary (GU), and vaginal toxicity, and rates of recurrence were analyzed. Three hundred four patients were included. Small cylinders were used in 51 patients (17%). Normal body mass index (BMI; pvaginal length (pvaginal symptoms were low (10%, 11%, and 19%, respectively). Small cylinder size was associated with increased likelihood of reporting acute GI (pvaginal symptoms. Small cylinder size was associated with higher risk of grade 1-2 vaginal stenosis (odds ratio [OR]=4.7; 95% confidence interval [CI]=1.5-14.7; p=0.007). There was no association between cylinder size and recurrence rate (p=0.55). VBT is generally very well tolerated, however, patients fitted with smaller cylinders (commonly nulligravid and low BMI) may have increased side effects. Further study to improve the dosimetry of VBT for patients requiring small cylinders may be worthwhile. Copyright © 2017. Asian Society of Gynecologic Oncology, Korean Society of Gynecologic Oncology

  20. Vortex shedding control of circular cylinder by perforated shroud in deep water

    Directory of Open Access Journals (Sweden)

    Ozkan Gokturk M.

    2017-01-01

    Full Text Available The aim of the present study is to control the vortex shedding downstream of a circular cylinder (inner cylinder by the existence of outer perforated cylinder concentrically located around the inner cylinder in deep water. The flow characteristics downstream of concentrically placed coupled cylinders were investigated quantitatively by the Particle Image Velocimetry (PIV technique. Diameter of the outer perforated cylinder and inner cylinder were kept constant as Do=100 mm and Di=50 mm. The depth-averaged free-stream velocity was also kept constant as U=100 mm/s which corresponded to the Reynolds number of ReDo=10,000 based on the outer cylinder diameter. Experiments were conducted for six porosities (β = 0.3, 0.4, 0.5, 0.6, 0.7 and 0.8 in order to show the effect of these parameters on the flow control. Maximum values of both Reynolds shear stress, and turbulence kinetic energy, significantly decreased with the existence of outer perforated cylinder and also, the location of peak magnitudes of turbulence statistics occurred at locations further downstream compared to the bare cylinder case. The most effective control was revealed for the porosity of β=0.7.

  1. Vortex shedding control of circular cylinder by perforated shroud in deep water

    Science.gov (United States)

    Ozkan, Gokturk M.; Durhasan, Tahir; Pinar, Engin; Aksoy, Muhammed M.; Akilli, Huseyin; Sahin, Beşir

    The aim of the present study is to control the vortex shedding downstream of a circular cylinder (inner cylinder) by the existence of outer perforated cylinder concentrically located around the inner cylinder in deep water. The flow characteristics downstream of concentrically placed coupled cylinders were investigated quantitatively by the Particle Image Velocimetry (PIV) technique. Diameter of the outer perforated cylinder and inner cylinder were kept constant as Do=100 mm and Di=50 mm. The depth-averaged free-stream velocity was also kept constant as U=100 mm/s which corresponded to the Reynolds number of ReDo=10,000 based on the outer cylinder diameter. Experiments were conducted for six porosities (β = 0.3, 0.4, 0.5, 0.6, 0.7 and 0.8) in order to show the effect of these parameters on the flow control. Maximum values of both Reynolds shear stress, and turbulence kinetic energy, significantly decreased with the existence of outer perforated cylinder and also, the location of peak magnitudes of turbulence statistics occurred at locations further downstream compared to the bare cylinder case. The most effective control was revealed for the porosity of β=0.7.

  2. Mycobacterial UvrD1 is a Ku-dependent DNA helicase that plays a role in multiple DNA repair events, including double-strand break repair.

    Science.gov (United States)

    Sinha, Krishna Murari; Stephanou, Nicolas C; Gao, Feng; Glickman, Michael S; Shuman, Stewart

    2007-05-18

    Mycobacterium tuberculosis and other bacterial pathogens have a Ku-dependent nonhomologous end joining pathway of DNA double-strand break repair. Here we identify mycobacterial UvrD1 as a novel interaction partner for Ku in a genome-wide yeast two-hybrid screen. UvrD1 per se is a vigorous DNA-dependent ATPase but a feeble DNA helicase. Ku stimulates UvrD1 to catalyze ATP-dependent unwinding of 3'-tailed DNAs. UvrD1, Ku, and DNA form a stable ternary complex in the absence of ATP. The Ku binding determinants are located in the distinctive C-terminal segment of UvrD1. A second mycobacterial paralog, UvrD2, is a vigorous Ku-independent DNA helicase. Ablation of UvrD1 sensitizes Mycobacterium smegmatis to killing by ultraviolet and ionizing radiation and to a single chromosomal break generated by I-SceI endonuclease. The physical and functional interactions of bacterial Ku and UvrD1 highlight the potential for cross-talk between components of nonhomologous end joining and nucleotide excision repair pathways.

  3. Distal corporoplasty for distal cylinders extrusion after penile prosthesis implantation.

    Science.gov (United States)

    Carrino, Maurizio; Chiancone, Francesco; Battaglia, Gaetano; Pucci, Luigi; Fedelini, Paolo

    2017-02-03

    Distal extrusion of cylinders is a potential complication of the penile prosthesis implantation. Several methods have been proposed for repairing a distal penile erosion. We present our preliminary experience in "Distal corporoplasty" technique. We enrolled 18 consecutive patients whose underwent a distal corporoplasty with simultaneous reimplantation of an "AMS 700 inflatable penile prosthesis (LGX)" from January 2013 to November 2015 at our hospital. All procedures were performed by a single surgical team. Intraoperative and postoperative complications have been classified and reported according to Satava6 and Clavien-Dindo (CD) system.7 Mean values with standard deviations (±SD) were computed and reported for all items. Mean age of the patients was 53.61 (±11.90) years. Mean body max index (BMI) was 24.22 (±2.51). Mean operative time was 85.2 (±13.1) minutes. Blood losses were minimal. No intraoperative complications are reported according to Satava classification. Four out of 18 patients (22.22%) experienced postoperative complications according to CD system. All patients had sexual intercourse for the first time postsurgery after a mean of 59.11 ± 2.08 days. Mean follow-up was 22.11 (±9.95). Distal extrusion of cylinders is a potential complication of the penile prosthesis implantation. Distal corporoplasty was first described by Mulcahy. He reported a series of 14 patients with a follow-up of about 2 years with optimal functional outcomes. Moreover, distal corporoplasty resulted in shorter operative time, better function, less pain, and fewer recurrences than Gortex windsock repair.10 In our experience, distal corporoplasty is a simple and safe procedure in the treatment of distal cylinders extrusion when the prosthetic material is not exposed to the exterior.

  4. ABOUT WAVEFORM OF BRAKING CYLINDER FILLING IN FREIGHT CARS

    Directory of Open Access Journals (Sweden)

    L. V. Ursuliak

    2016-04-01

    Full Text Available Purpose. As part of the scientific paper it is necessary to study the waveform impact of the braking cylinders filling on longitudinal train dynamics at different modes of braking. At this one should estimate the level of maximum longitudinal forces and braking distance size in freight cars of various lengths. Methodology. In this paper we attempt to approximate the actual diagram of braking cylinders filling with rational functions of varying degrees. In selection of coefficients in the required functions the highest values of the longitudinal forces and braking distances were used as controlled parameters. They were compared with similar values obtained as a result of experimental rides. The level of longitudinal forces and braking distances amount were evaluated by means of mathematical modeling of train longitudinal vibrations, caused by different braking modes. Findings. At mathematical modeling was assumed that the train consists of 60 uniform four-axle gondola cars, weight of 80 tons, equipped with air dispenser No. 483 included in the median operation, composite braking blocks, and one locomotive VL-8. Train before braking has been pre-stretched. Various types of pneumatic braking (emergency, full service and adjusting braking of the freight train on the horizontal section of the track were simulated. As the calculation results were obtained values of the longitudinal forces, braking distances amounts and reduction time in speed at various braking modes. Originality. Waveform impact of the braking cylinders filling on the longitudinal forces level and braking distances amount in freight trains were investigated. Also the longitudinal loading of freight trains at various pneumatic braking was investigated. Practical value. Obtained results can be used to assess the level of largest longitudinal forces and braking distances in the freight trains of different lengths by mathematical modeling of different braking modes.

  5. Tailoring Effective Media by Mie Resonances of Radially-Anisotropic Cylinders

    Directory of Open Access Journals (Sweden)

    Henrik Kettunen

    2015-05-01

    Full Text Available This paper studies constructing advanced effective materials using arrays of circular radially-anisotropic (RA cylinders. Homogenization of such cylinders is considered in an electrodynamic case based on Mie scattering theory. The homogenization procedure consists of two steps. First, we present an effectively isotropic model for individual cylinders, and second, we discuss the modeling of a lattice of RA cylinders. Radial anisotropy brings us extra parameters, which makes it possible to adjust the desired effective response for a fixed frequency. The analysis still remains simple enough, enabling a derivation of analytical design equations. The considered applications include generating artificial magnetism using all-dielectric cylinders, which is currently a very sought-after phenomenon in optical frequencies. We also study how negative refraction is achieved using magnetodielectric RA cylinders.

  6. Control of the flow in the annular region of a shrouded cylinder with splitter plate

    Directory of Open Access Journals (Sweden)

    Ozkan Gokturk Memduh

    2017-01-01

    Full Text Available In the present study, the flow control with a splitter plate was studied considering the annular region of a shrouded cylinder. The effect of splitter plate angle, α which was defined according to the cylinder centreline is investigated experimentally in deep water using Particle image Velocimetry (PIV technique and flow visualization by dye injection method. The range of splitter plate angle was selected within 60°≤ α ≤180° with an increment of 30°. The porosity of the shroud which is a perforated cylinder was selected as β=0.7 in order to have larger fluid entrainment through the cylinder. The results were compared with the no-plate case and showed that the splitter plate located in the annular region of shrouded cylinders is effective on reducing the turbulence levels just behind the cylinder base, as well as the near wake of the perforated shroud.

  7. Effect of non-homogeneity on orthotropic creep stresses in a pressurized circular cylinder

    Science.gov (United States)

    Sharma, Sanjeev; Panchal, Rekha

    2017-10-01

    The effect of anisotropy on the creep stresses of a functionally graded infinite hollow cylinder with inhomogeneity in terms of compressibility varying according to power law is investigated. Transition theory given by Seth for finite deformation is used for analysis of creep stresses which overcome the use of creep strain laws and jump conditions. Analytical solution for orthotropic and isotropic cylinder subjected to internal and external pressure is derived. The results indicate that the effect of inhomogeneity is very pronounced. Highly non-homogeneous isotropic material Steel with non-linear measure is safer for the design as compared to orthotropic material Barite and Uranium (alpha) as hoop stress generated are less. Circumferential creep stresses generated for the cylinder are less for highly functionally graded cylinder as compared to less functionally graded cylinder. Also, the cylinder with isotropic properties is on the safer side of design.

  8. Effect of intake swirl on the performance of single cylinder direct injection diesel engine

    Science.gov (United States)

    Sharma, Vinod Kumar; Mohan, Man; Mouli, Chandra

    2017-11-01

    In the present work, the effect of inlet manifold geometry and swirl intensity on the direct injection (DI) diesel engine performance was investigated experimentally. Modifications in inlet manifold geometry have been suggested to achieve optimized swirl for the better mixing of fuel with air. The intake swirl intensities of modified cylinder head were measured in swirl test rig at different valve lifts. Later, the overall performance of 435 CC DI diesel engine was measured using modified cylinder head. In addition, the performance of engine was compared for both modified and old cylinder head. For same operating conditions, the brake power and brake specific fuel consumption was improved by 6% and 7% respectively with modified cylinder head compared to old cylinder head. The maximum brake power of 9 HP was achieved for modified cylinder head. The results revealed that the intake swirl has great influence on engine performance.

  9. System and method of cylinder deactivation for optimal engine torque-speed map operation

    Science.gov (United States)

    Sujan, Vivek A; Frazier, Timothy R; Follen, Kenneth; Moon, Suk-Min

    2014-11-11

    This disclosure provides a system and method for determining cylinder deactivation in a vehicle engine to optimize fuel consumption while providing the desired or demanded power. In one aspect, data indicative of terrain variation is utilized in determining a vehicle target operating state. An optimal active cylinder distribution and corresponding fueling is determined from a recommendation from a supervisory agent monitoring the operating state of the vehicle of a subset of the total number of cylinders, and a determination as to which number of cylinders provides the optimal fuel consumption. Once the optimal cylinder number is determined, a transmission gear shift recommendation is provided in view of the determined active cylinder distribution and target operating state.

  10. Control of the flow in the annular region of a shrouded cylinder with splitter plate

    Science.gov (United States)

    Ozkan, Gokturk Memduh; Durhasan, Tahir; Pinar, Engin; Yenicun, Arda; Akilli, Huseyin; Sahin, Besir

    In the present study, the flow control with a splitter plate was studied considering the annular region of a shrouded cylinder. The effect of splitter plate angle, α which was defined according to the cylinder centreline is investigated experimentally in deep water using Particle image Velocimetry (PIV) technique and flow visualization by dye injection method. The range of splitter plate angle was selected within 60°≤ α ≤180° with an increment of 30°. The porosity of the shroud which is a perforated cylinder was selected as β=0.7 in order to have larger fluid entrainment through the cylinder. The results were compared with the no-plate case and showed that the splitter plate located in the annular region of shrouded cylinders is effective on reducing the turbulence levels just behind the cylinder base, as well as the near wake of the perforated shroud.

  11. Aharanov--Bohm currents in thin superconducting cylinders

    International Nuclear Information System (INIS)

    Kunstatter, G.; Revzen, M.; Trainor, L.E.H.

    1983-01-01

    The Aharanov--Bohm effect is the influence of classically inaccessible electromagnetic fields on quantum wave functions. In this paper we consider the Ginsburg--Landau (GL) equations for the stationary states of a thin, superconducting cylinder in the presence of a curl-free, static electromagnetic potential corresponding to zero fields. We solve the GL equations explicitly to obtain self-consistent solutions for the current density, the induced field and the free energy in a well-defined and accessible approximation. The analysis makes quantitative predictions which can, in principle, be experimentally tested to provide a clear and convincing demonstration of the Aharanov--Bohm effect

  12. Control of 12-Cylinder Camless Engine with Neural Networks

    OpenAIRE

    Ashhab Moh’d Sami

    2017-01-01

    The 12-cyliner camless engine breathing process is modeled with artificial neural networks (ANN’s). The inputs to the net are the intake valve lift (IVL) and intake valve closing timing (IVC) whereas the output of the net is the cylinder air charge (CAC). The ANN is trained with data collected from an engine simulation model which is based on thermodynamics principles and calibrated against real engine data. A method for adapting single-output feed-forward neural networks is proposed and appl...

  13. Terahertz surface plasmon polariton waveguiding with periodic metallic cylinders

    KAUST Repository

    Zhang, Ying

    2017-06-15

    We demonstrated a structure with periodic cylinders arranged bilaterally and a thin dielectric layer covered inside that supports bound modes of surface plasmon polaritons at terahertz frequencies. This structure can confine the surface plasmon polaritons in the lateral direction, and at the same time reduce the field expansion into space. We examined and explored the characteristics of several different structures using scanning near-field terahertz microscopy. The proposed designs pave a novel way to terahertz waveguiding and may have important applications in the development of flexible, wideband and compact photonic circuits operating at terahertz frequencies.

  14. Natural convection in polygonal enclosures with inner circular cylinder

    Directory of Open Access Journals (Sweden)

    Habibis Saleh

    2015-12-01

    Full Text Available This study investigates the natural convection induced by a temperature difference between cold outer polygonal enclosure and hot inner circular cylinder. The governing equations are solved numerically using built-in finite element method of COMSOL. The governing parameters considered are the number of polygonal sides, aspect ratio, radiation parameter, and Rayleigh number. We found that the number of contra-rotative cells depended on polygonal shapes. The convection heat transfer becomes constant at L / D > 0 . 77 and the polygonal shapes are no longer sensitive to the Nusselt number profile.

  15. Lift of a rotating circular cylinder in unsteady flows

    DEFF Research Database (Denmark)

    Carstensen, Stefan; Mandviwalla, Xerxes; Vita, Luca

    2012-01-01

    A cylinder rotating in steady current experiences a lift known as the Magnus effect. In the present study the effect of waves on the Magnus effect has been investigated. This situation is experienced with the novel floating offshore vertical axis wind turbine (VAWT) concept called the DEEPWIND...... concept, which incorporates a rotating spar buoy and thereby utilizes seawater as a roller-bearing. The a priori assumption and the results suggest that the lift in waves, to a first approximation, may be represented by a formulation similar to the well-known Morison formulation. The force coefficients...

  16. CFD model of laser additive manufacturing process of cylinders

    CSIR Research Space (South Africa)

    Tamsaout, T

    2017-11-01

    Full Text Available Figure 12: Temperature history and heating/cooling rates at points 1, 2, and 3 for the circular contour Figure 13: Temperature history and heating/cooling rates at points 1, 2, and 3 for hatch filling step Figure 14: Temperature history... and heating/cooling rates at point 4 (centre) for hatch filling step An important accumulation of heat in the already deposited part (cylinder) during the filling stage is observed. This accumulation can be attributed to the continuous nature of the process...

  17. Wake behind circular cylinder excited by spanwise periodic disturbances

    Science.gov (United States)

    Sasaki, Yudai; Uchida, Iwami; Sakakibara, Jun

    2017-11-01

    We experimentally investigated the influence of flow control of the wake behind a circular cylinder excited by temporal periodic disturbances with spanwise phase variations using plasma actuators, motivated by reducing drag forces by suppressing development of large scale vortices. Plasma actuators were segmented in the spanwise direction, phase differences were given to adjacent electrodes. This experiment was conducted at Re =8000 and the wake was visualized by PIV. Compared to without forcing, when the phase difference is 180° and non-dimensional forcing frequency is higher than approximately 1.0, small vortices induced by periodic disturbance emerged in the free shear layer and the drag forces decreased.

  18. Nanoaccuracy Position Control of a Pneumatic Cylinder Driven Table

    Science.gov (United States)

    Pai, Kei-Ren; Shih, Ming-Chang

    The development of ultraprecision positioning technology is urgently required with the incessant demand for higher accuracy in high technology manufacturing. In this study, therefore, a linear pneumatic-driven ultraprecision table is built; and, a velocity compensator is designed to overcome the stick-slip effect of the pneumatic table. The velocity compensation signal is directly added to the conventional PD and Fuzzy controller to control the table, respectively. This method is effective not only to overcome the stick-slip phenomenon of the cylinder but also to improve the positioning accuracy of the pneumatic servo system. The experimental results have shown that the table has the positioning accuracy of 20nm.

  19. The legal status of UF{sub 6}-cylinder testing and licensing in Germany (and Europe)

    Energy Technology Data Exchange (ETDEWEB)

    Wieser, K.E. [Federal Institute for Material Research and Testing (BAM), Berlin (Germany); Tietze, A. [Bergische Universitaet - Gesamthochschule Wuppertal (Germany)

    1991-12-31

    New German and European transport regulations for road and rail transport of UF{sub 6}-cylinders are presented, in particular those provisions which have direct impact on the majority of cylinders used in shipments touching ADR and RID member states. First experiences and difficulties in it`s application are highlighted taking into account experiences of a for running German regulation. A summary of research efforts on the behaviour of cylinders in fire environments concludes the paper.

  20. Brachistochrone curve of a fluid filled cylinder: Not too fast, not too slow

    OpenAIRE

    Gurram, Srikanth Sarma; Raja, Sharan; Panchagnula, Mahesh V.; Mahapatra, Pallab Sinha

    2017-01-01

    The brachistochrone curve for a non-dissipative particle tries to maximize inertia of the particle but for a fluid filled cylinder, increasing inertia would amount to increased dissipative losses. Hence the trade-off between inertia and dissipation plays a vital role in determining the brachistochrone curve of a fluid filled cylinder. This trade-off manifests itself in the form of an integro-differential equation governing the angular acceleration of the cylinder. Here, we compute the brachis...

  1. Thermography Inspection for Detection and Tracking of Composite Cylinder Damage During Load Testing

    Science.gov (United States)

    Zalameda, J. N.; Winfree, W. P.; Seebo, J. P.; Johnston, P. H.

    2010-01-01

    Two thermography techniques, passive and active, are used to detect damage initiation and progression in a cyclically loaded composite cylinder. The passive thermography tracks damage progression in real time during cyclic loading. Active flash thermography, using a flash tube enclosed within the cylinder, images delaminations in a cylinder under different loads. A differential thermography processing technique eliminates normal material variations and improves sensitivity to and sizing of delaminations. The thermography results were compared to nonimmersion ultrasonic results.

  2. Case Report: Facial and eye injury following a fridge cylinder gas explosion

    OpenAIRE

    Monsudi Kehinde Fasasi; Ehumadu Chioma Nwabugwu; Gero Na'allah Rumu

    2017-01-01

    Fridge cylinders contain liquefied petroleum gas (LPG), an inflammable gas of mixture of propane and butane [1]. It’s colourless but odourised to give warning during leakage. Injury from accidental fridge cylinder explosion is similar to any other blast injuries in terms of the release of hot gases, blast wave and metal fragments resulting in extensive skin burns, abrasions, penetrating injury and tissue loss [2-4]. Ocular trauma following gas cylinder explosion is rare however, Babar et al...

  3. Methods and results for stress analyses on 14-ton, thin-wall depleted UF6 cylinders

    International Nuclear Information System (INIS)

    Kirkpatrick, J.R.; Chung, C.K.; Frazier, J.L.; Kelley, D.K.

    1996-10-01

    Uranium enrichment operations at the three US gaseous diffusion plants produce depleted uranium hexafluoride (DUF 6 ) as a residential product. At the present time, the inventory of DUF 6 in this country is more than half a million tons. The inventory of DUF 6 is contained in metal storage cylinders, most of which are located at the gaseous diffusion plants. The principal objective of the project is to ensure the integrity of the cylinders to prevent causing an environmental hazard by releasing the contents of the cylinders into the atmosphere. Another objective is to maintain the cylinders in such a manner that the DUF 6 may eventually be converted to a less hazardous material for final disposition. An important task in the DUF 6 cylinders management project is determining how much corrosion of the walls can be tolerated before the cylinders are in danger of being damaged during routine handling and shipping operations. Another task is determining how to handle cylinders that have already been damaged in a manner that will minimize the chance that a breach will occur or that the size of an existing breach will be significantly increased. A number of finite element stress analysis (FESA) calculations have been done to analyze the stresses for three conditions: (1) while the cylinder is being lifted, (2) when a cylinder is resting on two cylinders under it in the customary two-tier stacking array, and (3) when a cylinder is resting on tis chocks on the ground. Various documents describe some of the results and discuss some of the methods whereby they have been obtained. The objective of the present report is to document as many of the FESA cases done at Oak Ridge for 14-ton thin-wall cylinders as possible, giving results and a description of the calculations in some detail

  4. Differences in Scour for Submerged and Surface Piercing Circular Cylinders in Tandem

    Science.gov (United States)

    Pulvino, N. T.; Riley, D.; Beninati, M. L.; Krane, M.; Fontaine, A.

    2012-12-01

    An experimental study was conducted to investigate how the scour hole of surface piercing and submerged cylinders in tandem is affected by the separation of the cylinders. The study was motivated by the need to predict the environmental effects of Marine Hydrokinetic (MHK) turbines arrays where the cylinders used represent the bluff bodies of MHK turbines. Small scale experiments were performed to find scour rate and scour statistics; including: scour size and deposition. The cases studied were tandem cylinders separated by 1, 2, 3, 4, 6, 8, 10, and 12 diameters (D = 2.54 cm). These studies were performed in a test section in the hydraulic flume facility (1.22-m-wide, 0.38-m-deep, and 9.75-m-long) at Bucknell University. The bottoms of each cylinder tested were taped in 0.318 cm color-coded increments and buried beneath the sediment. This allowed for visual determination of the scour rate by looking at how many strips had been uncovered at intervals over three hours of testing at live bed conditions. Subsequently, bed form topology was measured using an HR Wallingford 2D Sediment Bed Profiler with a low-powered laser distance sensor. Results show that surface piercing cylinders in tandem consistently have a wider scour hole than submerged cylinders. Furthermore, it is determined that the threshold for when the tandem cylinders have separate scour holes occurring at a separation of 10 diameters for both sets of cylinders.

  5. Scattering of Electromagnetic Radiation by Dimers of Two Finite Dielectric Cylinders

    Science.gov (United States)

    Kovtun-Kuzhel, V. A.; Ponyavina, A. N.

    2017-07-01

    We performed a numerical simulation of the scattering phase function for scattering of light by dimers of dielectric cylinders of finite length, using the volume integral equation formalism. We have studied the dependence of the scattering phase function on the optical and geometric parameters of the individual cylinders and their relative positions. We show that electrodynamic interaction between the cylinders leads to a substantial difference between the angular distribution of radiation scattered by this system and the angular distribution of radiation scattered by two cylinders with no electrodynamic coupling.

  6. Stress and magnetostriction in an infinite hollow superconducting cylinder with a filling in its central hole

    International Nuclear Information System (INIS)

    Yang, Yumei; Wang, Xingzhe

    2013-01-01

    Highlights: ► An analytical solution is showed to evaluate the stress of a superconductor cylinder. ► The stress concentration near the hole is certainly suppressed by a filling method. ► The penetration field parameter has a significant influence on stress of the cylinder. ► A maximum magnetostriction of the cylinder is achieved during a cycled field. -- Abstract: In this paper, the stress and magnetostriction induced by flux pinning in an infinite hollow cylinder of type-II superconductor with a non-superconductive filling in its central hole are analytically investigated. Based on the exponent model of critical state of superconductor, the magnetic and current distributions in the hollow cylinder superconductor are obtained firstly. The stress and magnetostriction of the composite superconductive cylinder are then formulated and the magnetoelastic behaviors are characterized analytically. The results show that the hoop stress concentration near the central hole is dominant due to the tension Lorentz force and it is certainly suppressed by filling a non-superconductive material in the hole. Without change of the magnetization characteristic of the superconductor, the filling material provides effective way to remedy the stress state at the verge of the hollow in the superconductive cylinder by adjusting its Young modulus. The magnetostriction of the composite cylinder under the cycled magnetic field is further presented. Effect of the applied maximum field, complete penetration field parameter and filling material parameter on the profile of the cycled magnetostriction for the composite superconducting cylinder is discussed in detail

  7. Low-Re flow past an isolated cylinder with rounded corners

    KAUST Repository

    Zhang, Wei

    2016-06-29

    Direct numerical simulation is performed for flow past an isolated cylinder at Re=1,000. The corners of the cylinder are rounded at different radii, with the non-dimensional radius of curvature varying from R+=R/D=0.000 (square cylinder with sharp corners) to 0.500 (circular cylinder), in which R is the corner radius and D is the cylinder diameter. Our objective is to investigate the effect of the rounded corners on the development of the separated and transitional flow past the cylinder in terms of time-averaged statistics, time-dependent behavior, turbulent statistics and three-dimensional flow patterns. Numerical results reveal that the rounding of the corners significantly reduces the time-averaged drag and the force fluctuations. The wake flow downstream of the square cylinder recovers the slowest and has the largest wake width. However, the statistical quantities do not monotonically vary with the corner radius, but exhibit drastic variations between the cases of square cylinder and partially rounded cylinders, and between the latter and the circular cylinder. The free shear layer separated from the R+=0.125 cylinder is the most stable in which the first roll up of the wake vortex occurs furthest from the cylinder and results in the largest recirculation bubble, whose size reduces as R+ further increases. The coherent and incoherent Reynolds stresses are most pronounced in the near-wake close to the reattachment point, while also being noticeable in the shear layer for the square and R+=0.125 cylinders. The wake vortices translate in the streamwise direction with a convection velocity that is almost constant at approximately 80% of the incoming flow velocity. These vortices exhibit nearly the same trajectory for the rounded cylinders and are furthest away from the wake centerline for the square one. The flow past the square cylinder is strongly three-dimensional as indicated by the significant primary and secondary enstrophy, while it is dominated by the

  8. Boundary value problems of the circular cylinders in the strain-gradient theory of linear elasticity

    International Nuclear Information System (INIS)

    Kao, B.G.

    1979-11-01

    Three boundary value problems in the strain-gradient theory of linear elasticity are solved for circular cylinders. They are the twisting of circular cylinder, uniformly pressuring of concentric circular cylinder, and pure-bending of simply connected cylinder. The comparisons of these solutions with the solutions in classical elasticity and in couple-stress theory reveal the differences in the stress fields as well as the apparent stress fields due to the influences of the strain-gradient. These aspects of the strain-gradient theory could be important in modeling the failure behavior of structural materials

  9. Flow structure from a horizontal cylinder coincident with a free surface in shallow water flow

    Directory of Open Access Journals (Sweden)

    Kahraman Ali

    2012-01-01

    Full Text Available Vortex formation from a horizontal cylinder coincident with a free surface of a shallow water flow having a depth of 25.4 [mm] was experimentally investigated using the PIV technique. Instantaneous and time-averaged flow patterns in the wake region of the cylinder were examined for three different cylinder diameter values under the fully developed turbulent boundary layer condition. Reynolds numbers were in the range of 1124£ Re£ 3374 and Froude numbers were in the range of 0.41 £ Fr £ 0.71 based on the cylinder diameter. It was found that a jet-like flow giving rise to increasing the flow entrainment between the core and wake regions depending on the cylinder diameter was formed between the lower surface of the cylinder and bottom surface of the channel. Vorticity intensity, Reynolds stress correlations and the primary recirculating bubble lengths were grown to higher values with increasing the cylinder diameter. On the other hand, in the case of the lowest level of the jet-like flow emanating from the beneath of the smallest cylinder, the variation of flow characteristics were attenuated significantly in a shorter distance. The variation of the reattachment location of the separated flow to the free-surface is a strong function of the cylinder diameter and the Froude number.

  10. Electrorefining cell with parallel electrode/concentric cylinder cathode

    Science.gov (United States)

    Gay, Eddie C.; Miller, William E.; Laidler, James J.

    1997-01-01

    A cathode-anode arrangement for use in an electrolytic cell is adapted for electrochemically refining spent nuclear fuel from a nuclear reactor and recovering purified uranium for further treatment and possible recycling as a fresh blanket or core fuel in a nuclear reactor. The arrangement includes a plurality of inner anodic dissolution baskets that are each attached to a respective support rod, are submerged in a molten lithium halide salt, and are rotationally displaced. An inner hollow cylindrical-shaped cathode is concentrically disposed about the inner anodic dissolution baskets. Concentrically disposed about the inner cathode in a spaced manner are a plurality of outer anodic dissolution baskets, while an outer hollow cylindrical-shaped is disposed about the outer anodic dissolution baskets. Uranium is transported from the anode baskets and deposited in a uniform cylindrical shape on the inner and outer cathode cylinders by rotating the anode baskets within the molten lithium halide salt. Scrapers located on each anode basket abrade and remove the spent fuel deposits on the surfaces of the inner and outer cathode cylinders, with the spent fuel falling to the bottom of the cell for removal. Cell resistance is reduced and uranium deposition rate enhanced by increasing the electrode area and reducing the anode-cathode spacing. Collection efficiency is enhanced by trapping and recovery of uranium dendrites scrapped off of the cylindrical cathodes which may be greater in number than two.

  11. Acoustic scattering by multiple elliptical cylinders using collocation multipole method

    International Nuclear Information System (INIS)

    Lee, Wei-Ming

    2012-01-01

    This paper presents the collocation multipole method for the acoustic scattering induced by multiple elliptical cylinders subjected to an incident plane sound wave. To satisfy the Helmholtz equation in the elliptical coordinate system, the scattered acoustic field is formulated in terms of angular and radial Mathieu functions which also satisfy the radiation condition at infinity. The sound-soft or sound-hard boundary condition is satisfied by uniformly collocating points on the boundaries. For the sound-hard or Neumann conditions, the normal derivative of the acoustic pressure is determined by using the appropriate directional derivative without requiring the addition theorem of Mathieu functions. By truncating the multipole expansion, a finite linear algebraic system is derived and the scattered field can then be determined according to the given incident acoustic wave. Once the total field is calculated as the sum of the incident field and the scattered field, the near field acoustic pressure along the scatterers and the far field scattering pattern can be determined. For the acoustic scattering of one elliptical cylinder, the proposed results match well with the analytical solutions. The proposed scattered fields induced by two and three elliptical–cylindrical scatterers are critically compared with those provided by the boundary element method to validate the present method. Finally, the effects of the convexity of an elliptical scatterer, the separation between scatterers and the incident wave number and angle on the acoustic scattering are investigated.

  12. Control of 12-Cylinder Camless Engine with Neural Networks

    Directory of Open Access Journals (Sweden)

    Ashhab Moh’d Sami

    2017-01-01

    Full Text Available The 12-cyliner camless engine breathing process is modeled with artificial neural networks (ANN’s. The inputs to the net are the intake valve lift (IVL and intake valve closing timing (IVC whereas the output of the net is the cylinder air charge (CAC. The ANN is trained with data collected from an engine simulation model which is based on thermodynamics principles and calibrated against real engine data. A method for adapting single-output feed-forward neural networks is proposed and applied to the camless engine ANN model. As a consequence the overall 12-cyliner camless engine feedback controller is upgraded and the necessary changes are implemented in order to contain the adaptive neural network with the objective of tracking the cylinder air charge (driver’s torque demand while minimizing the pumping losses (increasing engine efficiency. All the needed measurements are extracted only from the two conventional and inexpensive sensors, namely, the mass air flow through the throttle body (MAF and the intake manifold absolute pressure (MAP sensors. The feedback controller’s capability is demonstrated through computer simulation.

  13. A Method for Turbocharging Four-Stroke Single Cylinder Engines

    Science.gov (United States)

    Buchman, Michael; Winter, Amos

    2014-11-01

    Turbocharging is not conventionally used with single cylinder engines due to the timing mismatch between when the turbo is powered and when it can deliver air to the cylinder. The proposed solution involves a fixed, pressurized volume - which we call an air capacitor - on the intake side of the engine between the turbocharger and intake valves. The capacitor acts as a buffer and would be implemented as a new style of intake manifold with a larger volume than traditional systems. This talk will present the flow analysis used to determine the optimal size for the capacitor, which was found to be four to five times the engine capacity, as well as its anticipated contributions to engine performance. For a capacitor sized for a one-liter engine, the time to reach operating pressure was found to be approximately two seconds, which would be acceptable for slowly accelerating applications and steady state applications. The air density increase that could be achieved, compared to ambient air, was found to vary between fifty percent for adiabatic compression and no heat transfer from the capacitor, to eighty percent for perfect heat transfer. These increases in density are proportional to, to first order, the anticipated power increases that could be realized. This material is based upon work supported by the National Science Foundation Graduate Research Fellowship under Grant No. 1122374.

  14. Manipulation of plasmonic resonances in graphene coated dielectric cylinders

    KAUST Repository

    Ge, Lixin

    2016-11-16

    Graphene sheets can support surface plasmon as the Dirac electrons oscillate collectively with electromagnetic waves. Compared with the surface plasmon in conventional metal (e.g., Ag and Au), graphene plasmonic owns many remarkable merits especially in Terahertz and far infrared frequencies, such as deep sub-wavelength, low loss, and high tunability. For graphene coated dielectric nano-scatters, localized surface plasmon (LSP)exist and can be excited under specific conditions. The LSPs are associated with the Mie resonance modes, leading to extraordinary large scattering and absorption cross section. In this work, we study systematically the optical scattering properties for graphene coated dielectric cylinders. It is found that the LSP can be manipulated by geometrical parameters and external electric gating. Generally, the resonance frequencies for different resonance modes are not the same. However, under proper design, we show that different resonance modes (e.g., dipole mode, quadruple mode etc.) can be excited at the same frequency. Thus, the scattering and absorption by graphene coated dielectric cylinders can indeed overcome the single channel limit. Our finding may open up new avenues in applications for the graphene-based THz optoelectronic devices.

  15. Polymerase and Exonuclease Activities in Herpes Simplex Virus Type 1 DNA Polymerase Are Not Highly Coordinated

    Science.gov (United States)

    2015-01-01

    The herpes polymerase–processivity factor complex consists of the catalytic UL30 subunit containing both polymerase and proofreading exonuclease activities and the UL42 subunit that acts as a processivity factor. Curiously, the highly active exonuclease has minimal impact on the accumulation of mismatches generated by the polymerase activity. We utilized a series of oligonucleotides of defined sequence to define the interactions between the polymerase and exonuclease active sites. Exonuclease activity requires unwinding of two nucleotides of the duplex primer–template. Surprisingly, even though the exonuclease rate is much higher than the rate of DNA dissociation, the exonuclease degrades both single- and double-stranded DNA in a nonprocessive manner. Efficient proofreading of incorrect nucleotides incorporated by the polymerase would seem to require efficient translocation of DNA between the exonuclease and polymerase active sites. However, we found that translocation of DNA from the exonuclease to polymerase active site is remarkably inefficient. Consistent with inefficient translocation, the DNA binding sites for the exonuclease and polymerase active sites appear to be largely independent, such that the two activities appear noncoordinated. Finally, the presence or absence of UL42 did not impact the coordination of the polymerase and exonuclease activities. In addition to providing fundamental insights into how the polymerase and exonuclease function together, these activities provide a rationale for understanding why the exonuclease minimally impacts accumulation of mismatches by the purified polymerase and raise the question of how these two activities function together in vivo. PMID:25517265

  16. Mitochondrial DNA.

    Science.gov (United States)

    Wright, Russell G.; Bottino, Paul J.

    1986-01-01

    Provides background information for teachers on mitochondrial DNA, pointing out that it may have once been a free-living organism. Includes a ready-to-duplicate exercise titled "Using Microchondrial DNA to Measure Evolutionary Distance." (JN)

  17. Modeling DNA

    Science.gov (United States)

    Robertson, Carol

    2016-01-01

    Deoxyribonucleic acid (DNA) is life's most amazing molecule. It carries the genetic instructions that almost every organism needs to develop and reproduce. In the human genome alone, there are some three billion DNA base pairs. The most difficult part of teaching DNA structure, however, may be getting students to visualize something as small as a…

  18. The influence of chromatin structure on the frequency of radiation-induced DNA strand breaks: a study using nuclear and nucleoid monolayers

    International Nuclear Information System (INIS)

    Ljungman, M.

    1991-01-01

    To assess the influence of chromatin structure on the frequency of radiation-induced DNA strand breaks, the alkaline unwinding technique was applied to nuclear and nucleoid monolayers. These chromatin substrates were prepared by treating human fibroblasts grown as monolayers with the nonionic detergent Triton X-100 and varying concentrations of cations. The chromatin structure was modified either by a stepwise removal of DNA-bound proteins by extraction in increasing concentrations of monovalent salt, or by the addition or deletion of mono- and divalent cations to condense or decondense the chromatin, respectively. It was found that the stepwise removal of DNA-bound proteins from the chromatin dramatically increased the frequency of radiation-induced DNA strand breaks. The DNA-bound proteins showed a qualitative difference in their ability to protect the DNA where proteins removed by salt concentrations above 1.0 M exerted the greatest protection. Furthermore, the frequency of radiation-induced DNA strand breaks was found to be 6 times lower in condensed chromatin than in decondensed chromatin and about 80 times lower than in protein-depleted chromatin. It is concluded that the presence of DNA-bound proteins and the folding of the chromatin into higher-order structures protect the DNA against radiation-induced strand breaks

  19. Mathematical modelling of the automated FADU assay for the quantification of DNA strand breaks and their repair in human peripheral mononuclear blood cells

    International Nuclear Information System (INIS)

    Junk, Michael; Salzwedel, Judy; Sindlinger, Thilo; Bürkle, Alexander; Moreno-Villanueva, Maria

    2014-01-01

    Cells continuously undergo DNA damage from exogenous agents like irradiation or genotoxic chemicals or from endogenous radicals produced by normal cellular metabolic activities. DNA strand breaks are one of the most common genotoxic lesions and they can also arise as intermediates of DNA repair activity. Unrepaired DNA damage can lead to genomic instability, which can massively compromise the health status of organisms. Therefore it is important to measure and quantify DNA damage and its repair. We have previously published an automated method for measuring DNA strand breaks based on fluorimetric detection of alkaline DNA unwinding [1], and here we present a mathematical model of the FADU assay, which enables to an analytic expression for the relation between measured fluorescence and the number of strand breaks. Assessment of the formation and also the repair of DNA strand breaks is a crucial functional parameter to investigate genotoxicity in living cells. A reliable and convenient method to quantify DNA strand breakage is therefore of significant importance for a wide variety of scientific fields, e.g. toxicology, pharmacology, epidemiology and medical sciences

  20. Accuracy of Oxygen Flow Delivered by Compressed-Gas Cylinders in Hospital and Prehospital Emergency Care.

    Science.gov (United States)

    Duprez, Frédéric; Michotte, Jean Bernard; Cuvelier, Gregory; Legrand, Alexandre; Mashayekhi, Sharam; Reychler, Gregory

    2018-03-01

    Oxygen cylinders are widely used both in hospital and prehospital care. Excessive or inappropriate F IO 2 may be critical for patients with hypercapnia or hypoxia. Moreover, over-oxygenation could be deleterious in ischemic disorders. Supplemental oxygen from oxygen cylinder should therefore be delivered accurately. The aim of this study was to assess the accuracy of oxygen flows for oxygen cylinder in hospital and prehospital care. A prospective trial was conducted to evaluate accuracy of delivered oxygen flows (2, 4, 6, 9 and 12 L/min) for different oxygen cylinder ready for use in different hospital departments. Delivered flows were analyzed randomly using a calibrated thermal mass flow meter. Two types of oxygen cylinder were evaluated: 78 oxygen cylinder with a single-stage regulator and 70 oxygen cylinder with a dual-stage regulator. Delivered flows were compared to the required oxygen flow. The residual pressure value for each oxygen cylinder was considered. A coefficient of variation was calculated to compare the variability of the delivered flow between the two types of oxygen cylinder. The median values of delivered flows were all ≥ 100% of the required flow for single stage (range 100-109%) and cylinders (no. = 148) ranged from 73 to 2,900 pounds per square inch, and no significant difference was observed between the 2 types ( P = .86). The calculated coefficient of variation ranged from 7% (±1%) for dual stage to 8% (±2%) for single stage. This study shows good accuracy of oxygen flow delivered via oxygen cylinders. This accuracy was higher with dual stage. Single stage was also accurate, however, at low flow this accuracy is slightly less. Moreover, with single stage, when residual pressure decreases, the median value of delivered flow decreased. Copyright © 2018 by Daedalus Enterprises.

  1. Results of the remote sensing feasibility study for the uranium hexafluoride storage cylinder yard program

    International Nuclear Information System (INIS)

    Balick, L.K.; Bowman, D.R.

    1997-02-01

    The US DOE manages the safe storage of approximately 650,000 tons of depleted uranium hexafluoride remaining from the Cold War. This slightly radioactive, but chemically active, material is contained in more than 46,000 steel storage cylinders that are located at Oak Ridge, Tennessee; Paducah, Kentucky; and Portsmouth, Ohio. Some of the cylinders are more than 40 years old, and approximately 17,500 are considered problem cylinders because their physical integrity is questionable. These cylinders require an annual visual inspection. The remainder of the 46,000-plus cylinders must be visually inspected every four years. Currently, the cylinder inspection program is extremely labor intensive. Because these inspections are accomplished visually, they may not be effective in the early detection of leaking cylinders. The inspection program requires approximately 12--14 full-time-equivalent (FTE) employees. At the cost of approximately $125K per FTE, this translates to $1,500K per annum just for cylinder inspection. As part of the technology-development portion of the DOE Cylinder Management Program, the DOE Office of Facility Management requested the Remote Sensing Laboratory (RSL) to evaluate remote sensing techniques that have potential to increase the effectiveness of the inspection program and, at the same time, reduce inspection costs and personnel radiation exposure. During two site visits (March and May 1996) to the K-25 Site at Oak Ridge, TN, RSL personnel tested and characterized seven different operating systems believed to detect leakage, surface contamination, thickness and corrosion of cylinder walls, and general area contamination resulting from breached cylinders. The following techniques were used and their performances are discussed: Laser-induced fluorescent imaging; Long-range alpha detection; Neutron activation analysis; Differential gamma-ray attenuation; Compton scatterometry; Active infrared inspection; and Passive thermal infrared imaging

  2. Results of the remote sensing feasibility study for the uranium hexafluoride storage cylinder yard program

    Energy Technology Data Exchange (ETDEWEB)

    Balick, L.K.; Bowman, D.R. [Bechtel Nevada, Las Vegas, NV (United States). Remote Sensing Lab.; Bounds, J.H. [Los Alamos National Lab., NM (United States)] [and others

    1997-02-01

    The US DOE manages the safe storage of approximately 650,000 tons of depleted uranium hexafluoride remaining from the Cold War. This slightly radioactive, but chemically active, material is contained in more than 46,000 steel storage cylinders that are located at Oak Ridge, Tennessee; Paducah, Kentucky; and Portsmouth, Ohio. Some of the cylinders are more than 40 years old, and approximately 17,500 are considered problem cylinders because their physical integrity is questionable. These cylinders require an annual visual inspection. The remainder of the 46,000-plus cylinders must be visually inspected every four years. Currently, the cylinder inspection program is extremely labor intensive. Because these inspections are accomplished visually, they may not be effective in the early detection of leaking cylinders. The inspection program requires approximately 12--14 full-time-equivalent (FTE) employees. At the cost of approximately $125K per FTE, this translates to $1,500K per annum just for cylinder inspection. As part of the technology-development portion of the DOE Cylinder Management Program, the DOE Office of Facility Management requested the Remote Sensing Laboratory (RSL) to evaluate remote sensing techniques that have potential to increase the effectiveness of the inspection program and, at the same time, reduce inspection costs and personnel radiation exposure. During two site visits (March and May 1996) to the K-25 Site at Oak Ridge, TN, RSL personnel tested and characterized seven different operating systems believed to detect leakage, surface contamination, thickness and corrosion of cylinder walls, and general area contamination resulting from breached cylinders. The following techniques were used and their performances are discussed: Laser-induced fluorescent imaging; Long-range alpha detection; Neutron activation analysis; Differential gamma-ray attenuation; Compton scatterometry; Active infrared inspection; and Passive thermal infrared imaging.

  3. The Q Motif Is Involved in DNA Binding but Not ATP Binding in ChlR1 Helicase.

    Directory of Open Access Journals (Sweden)

    Hao Ding

    Full Text Available Helicases are molecular motors that couple the energy of ATP hydrolysis to the unwinding of structured DNA or RNA and chromatin remodeling. The conversion of energy derived from ATP hydrolysis into unwinding and remodeling is coordinated by seven sequence motifs (I, Ia, II, III, IV, V, and VI. The Q motif, consisting of nine amino acids (GFXXPXPIQ with an invariant glutamine (Q residue, has been identified in some, but not all helicases. Compared to the seven well-recognized conserved helicase motifs, the role of the Q motif is less acknowledged. Mutations in the human ChlR1 (DDX11 gene are associated with a unique genetic disorder known as Warsaw Breakage Syndrome, which is characterized by cellular defects in genome maintenance. To examine the roles of the Q motif in ChlR1 helicase, we performed site directed mutagenesis of glutamine to alanine at residue 23 in the Q motif of ChlR1. ChlR1 recombinant protein was overexpressed and purified from HEK293T cells. ChlR1-Q23A mutant abolished the helicase activity of ChlR1 and displayed reduced DNA binding ability. The mutant showed impaired ATPase activity but normal ATP binding. A thermal shift assay revealed that ChlR1-Q23A has a melting point value similar to ChlR1-WT. Partial proteolysis mapping demonstrated that ChlR1-WT and Q23A have a similar globular structure, although some subtle conformational differences in these two proteins are evident. Finally, we found ChlR1 exists and functions as a monomer in solution, which is different from FANCJ, in which the Q motif is involved in protein dimerization. Taken together, our results suggest that the Q motif is involved in DNA binding but not ATP binding in ChlR1 helicase.

  4. Dna Sequencing

    Science.gov (United States)

    Tabor, Stanley; Richardson, Charles C.

    1995-04-25

    A method for sequencing a strand of DNA, including the steps off: providing the strand of DNA; annealing the strand with a primer able to hybridize to the strand to give an annealed mixture; incubating the mixture with four deoxyribonucleoside triphosphates, a DNA polymerase, and at least three deoxyribonucleoside triphosphates in different amounts, under conditions in favoring primer extension to form nucleic acid fragments complementory to the DNA to be sequenced; labelling the nucleic and fragments; separating them and determining the position of the deoxyribonucleoside triphosphates by differences in the intensity of the labels, thereby to determine the DNA sequence.

  5. Thermal behaviour of the type 30 B cylinder equipped with the 21 PF.1 overpack and study of protective covers for the 48 Y cylinder valve

    International Nuclear Information System (INIS)

    Warniez, P.; Ringot, C.; Bernard, H.

    1988-12-01

    This paper describes the tests which have been performed in France: first to verify the behaviour of 30B cylinders with their 21 PF.1 protective overpack, secondly to develop a better mechanical protection of the valve. The thermal tests have been performed on real packagings filled with UF 6 , after the mechanical AIEA tests (free drop 9 m and 1 m on a pitch). The results were very satisfactory, the maximal temperatures which were measured on the external overpack of the 30B cylinder being much lower than the filling temperature. In the Mont Louis wreckage, some of the valves of 48Y cylinders were damaged. A new valve protector was designed and was tested under impact situations. The tests have demonstrated that the new design which has the same weight as the original one and which may be used without any modifications of the cylinder, has a better behaviour, increasing the safety during transport

  6. The Change of Printouts' Quality Depending on Pressure of a Blanket Cylinder Against an Impression Cylinder and a Plate Cylinder in Offset Machine

    Directory of Open Access Journals (Sweden)

    Jurkiewicz Agnieszka

    2014-03-01

    Full Text Available According to lots of books, the pressure in offset printing affects the optical density and the quality of printouts. One of the quality parameters is a tone value increase. An advantage of our research method is obtaining printing effects for different pressures on one printout, thus meaning for identical printing conditions. We obtained the same printing conditions through using different amounts of underlay sheets fixed to the blanket cylinder, under a blanket. The pressure was increased from optimal settings - in accordance with the machine manufacturer’s recommendation. The test printouts were printed using Adast Dominant 515, on a coated and an uncoated paper. The optical density value was measured on the tone value scale from 10% to 100% stepping regularly by 10%. For this scale the tone value increase was computed. The research shows that for both types of paper the optical density and the tone value increase changes not very much above the optimal pressure recommended by the machine manufacturer. A difference in the optical density and in the tone value increase is bigger for coated paper than for uncoated paper. Changes in these two parameters are negligible in places where used form 0 to 4 underlay sheets and are quite significant in the place where 5 underlay sheets were.

  7. Synthesis of PLGA nanoparticles of tea polyphenols and their strong in vivo protective effect against chemically induced DNA damage

    Directory of Open Access Journals (Sweden)

    Srivastava AK

    2013-04-01

    Full Text Available Amit Kumar Srivastava,1 Priyanka Bhatnagar,2 Madhulika Singh,1 Sanjay Mishra,1 Pradeep Kumar,2 Yogeshwer Shukla,1 Kailash Chand Gupta1,2 1Proteomics Laboratory, Indian Institute of Toxicology Research (CSIR, Lucknow, India; 2Nucleic Acid Research Laboratory, Institute of Genomics and Integrative Biology (CSIR, Delhi University Campus, India Abstract: In spite of proficient results of several phytochemicals in preclinical settings, the conversion rate from bench to bedside is not very encouraging. Many reasons are attributed to this limited success, including inefficient systemic delivery and bioavailability under in vivo conditions. To achieve improved efficacy, polyphenolic constituents of black (theaflavin [TF] and green (epigallocatechin-3-gallate [EGCG] tea in poly(lactide-co-glycolide nanoparticles (PLGA-NPs were entrapped with entrapment efficacy of ~18% and 26%, respectively. Further, their preventive potential against 7,12-dimethylbenzanthracene (DMBA-induced DNA damage in mouse skin using DNA alkaline unwinding assay was evaluated. Pretreatment (topically of mouse skin with either TF or EGCG (100 µg/mouse doses exhibits protection of 45.34% and 28.32%, respectively, against DMBA-induced DNA damage. However, pretreatment with TF-loaded PLGA-NPs protects against DNA damage 64.41% by 1/20th dose of bulk, 71.79% by 1/10th dose of bulk, and 72.46% by 1/5th dose of bulk. Similarly, 51.28% (1/20th of bulk, 57.63% (1/10th of bulk, and 63.14% (1/5th of bulk prevention was noted using EGCG-loaded PLGA-NP doses. These results showed that tea polyphenol-loaded PLGA-NPs have ~30-fold dose-advantage than bulk TF or EGCG doses. Additionally, TF- or EGCG-loaded PLGA-NPs showed significant potential for induction of DNA repair genes (XRCC1, XRCC3, and ERCC3 and suppression of DNA damage responsive genes (p53, p21, MDM2, GADD45α, and COX-2 as compared with respective bulk TF or EGCG doses. Taken together, TF- or EGCG-loaded PLGA-NPs showed a superior

  8. Gas storage cylinder formed from a composition containing thermally exfoliated graphite

    Science.gov (United States)

    Prud'Homme, Robert K. (Inventor); Aksay, Ilhan A. (Inventor)

    2012-01-01

    A gas storage cylinder or gas storage cylinder liner, formed from a polymer composite, containing at least one polymer and a modified graphite oxide material, which is a thermally exfoliated graphite oxide with a surface area of from about 300 m(exp 2)/g to 2600 m(exp 2)2/g.

  9. 78 FR 58604 - Safety Advisory: Unauthorized Filling of Compressed Gas Cylinders

    Science.gov (United States)

    2013-09-24

    .... PHMSA-2013-0195, Notice No. 13-12] Safety Advisory: Unauthorized Filling of Compressed Gas Cylinders... compressed gas cylinders (DOT Specification 3A, 3AA and 3AL) without verifying that they met the appropriate... 9, 2013 that Komer Carbonic [[Page 58605

  10. Mixed convection of ferrofluids in a lid driven cavity with two rotating cylinders

    Directory of Open Access Journals (Sweden)

    Fatih Selimefendigil

    2015-09-01

    Full Text Available Mixed convection of ferrofluid filled lid driven cavity in the presence of two rotating cylinders were numerically investigated by using the finite element method. The cavity is heated from below, cooled from driven wall and rotating cylinder surfaces and side vertical walls of the cavity are assumed to be adiabatic. A magnetic dipole source is placed below the bottom wall of the cavity. The study is performed for various values of Reynolds numbers (100 ≤ Re ≤ 1000, angular rotational speed of the cylinders (−400 ≤ Ω ≤ 400, magnetic dipole strengths (0 ≤ γ ≤ 500, angular velocity ratios of the cylinders (0.25≤Ωi/Ωj≤4 and diameter ratios of the cylinders (0.5≤Di/Dj≤2. It is observed that flow patterns and thermal transport within the cavity are affected by variation in Reynolds number and magnetic dipole strength. The results of this investigation revealed that cylinder angular velocities, ratio of the angular velocities and diameter ratios have profound effect on heat transfer enhancement within the cavity. Averaged heat transfer enhancements of 181.5 % is achieved for clockwise rotation of the cylinder at Ω = −400 compared to motionless cylinder case. Increasing the angular velocity ratio from Ω2/Ω1=0.25 to Ω2/Ω1=4 brings about 91.7 % of heat transfer enhancement.

  11. Mass transfer behavior of rotating square cylinder electrochemical reactor in relation to wastewater treatment

    International Nuclear Information System (INIS)

    Abdel-Aziz, M.S.M.; El-Shazly, A.H.; Farag, H.A.; Sedahmed, G.H.

    2011-01-01

    Highlights: → The work explores a new electrochemical reactor by using square rotating cylinders. → The results show that it is superior to the traditional circular rotating cylinder. → A dimensionless design equation for the new reactor was correlated. → The oxalic acid removal by the new reactor was succeeded and found promising. → The energy consumption per kg oxalic acid removed by the unit was calculated. - Abstract: Rates of mass transfer at a rotating square cylinder were measured by an electrochemical technique which involved measuring the limiting current of the cathodic reduction of K 3 Fe(CN) 6 in a large excess of NaOH solution. Variables studied were: cylinder rotation speed, physical properties of the solution and cylinder equivalent diameter. The data for the condition 1577 0.33 Re 0.45 For a given set of conditions the rate of mass transfer at the square rotating cylinder was found to be higher than that at the traditional circular rotating cylinder by an amount ranging from 47% to 200% depending on Re. The use of the square rotating cylinder electrode in removing oxalic acid from wastewater by anodic oxidation on Pb/PbO anode was examined and found to be promising.

  12. Investigation of the Rolling Motion of a Hollow Cylinder Using a Smartphone's Digital Compass

    Science.gov (United States)

    Wattanayotin, Phattara; Puttharugsa, Chokchai; Khemmani, Supitch

    2017-01-01

    This study used a smartphone's digital compass to observe the rolling motion of a hollow cylinder on an inclined plane. The smartphone (an iPhone 4s) was attached to the end of one side of a hollow cylinder to record the experimental data using the SensorLog application. In the experiment, the change of angular position was measured by the…

  13. Variation of the Friction Coefficient for a Cylinder Rolling down an Inclined Board

    Science.gov (United States)

    Yan, Zixiang; Xia, Heming; Lan, Yueheng; Xiao, Jinghua

    2018-01-01

    A cylinder rolling down an inclined board is a commonly seen and interesting object to study and it is also easy to experiment with and model. Following what has become a popular practice, we use smartphones to measure the angular acceleration of a cylinder rolling down a plane of different inclining angles. The friction force deviates from the…

  14. Combined natural convection and radiation from heated cylinders inside a container

    Science.gov (United States)

    Zhao, Z.; Poulikakos, D.; Ren, Z.

    1992-12-01

    In this article a numerical investigation verified by experiments is reported on steady-state heat transfer from three electrically heated cylinders equally spaced and resting at the bottom wall of a rectangular container. The investigation simulates heat transfer from power cables sparsely laid inside rectangular trays. The results indicate that a multicellular flow pattern existed in the system. At high Grashof numbers, the flow in the right half of the system consisted of a large cell rotating above the cylinders and two small cells trapped between the cylinders. Results for the average Nusselt number and the average and maximum temperature of the center cylinder are also reported in the present study. The average Nusselt number differs markedly from that for a single cylinder in an infinite space underlying the importance of the interaction of the cylinders with each other and with the container. The spacing of the cylinders had a visible effect on the magnitude and the location of the maximum temperature of the center cylinder.

  15. 76 FR 55736 - Safety Advisory: Unauthorized Marking of Compressed Gas Cylinders

    Science.gov (United States)

    2011-09-08

    ... certain of high- and low-pressure compressed gas cylinders, primarily fire extinguishers, by Atlas Fire.... Investigations conducted by PHMSA's field operations in 2009, 2010, and 2011, revealed that some high- and low- pressure cylinders serviced by Atlas Fire Protection were marked and represented as requalified (visually...

  16. Rotational friction coefficient of a permeable cylinder in a viscous fluid

    NARCIS (Netherlands)

    Wiegel, F.W.

    1979-01-01

    An exact expression is derived for the rotational friction coefficient of a cylinder of infinite length and constant permeability immersed in an incompressible viscous fluid. An asymptotic expression for the translational friction coefficient of a permeable cylinder moving in a sheet of viscous

  17. 49 CFR 178.60 - Specification 8AL steel cylinders with porous fillings for acetylene.

    Science.gov (United States)

    2010-10-01

    ... at least 24 times thickness with a width not over 6 times thickness is authorized when a cylinder... permanent strain occurs may be determined with sufficient accuracy by calculating the elastic extension of... filling material is authorized if the total clearance between the cylinder shell and filling material...

  18. Reduction of sound transmission across plenum windows by incorporating an array of rigid cylinders

    Science.gov (United States)

    Tang, S. K.

    2018-02-01

    The potential improvement of plenum window noise reduction by installing rigid circular cylinder arrays into the window cavity is investigated numerically using the finite-element method in this study. A two-dimensional approach is adopted. The sound transmission characteristics and propagation within the plenum window are also examined in detail. Results show that the installation of the cylinders in general gives rise to broadband improvement of noise reduction across a plenum window regardless of the direction of sound incidence. Such acoustical performance becomes better when more cylinder columns are installed, but it is suggested that the number of cylinder rows should not exceed two. Results also show that the cylinder positions relative to the nodal/anti-nodal planes of the acoustic modes are crucial in the noise reduction enhancement mechanisms. Noise reduction can further be enhanced by staggering the cylinder rows, such that each cylinder row supports the development of a different acoustic mode. For the simple cylinder arrangements considered in this study, the traffic noise reduction enhancement observed in this study can be as high as 4-5 dB, which is already comparable to or higher than the maximum achieved by installing sound absorption into a plenum window.

  19. Lift and Drag on Cylinder of Octagonal Cross-Section in a Turbulent Stream

    Directory of Open Access Journals (Sweden)

    Md. Jomir Hossain

    2013-12-01

    Full Text Available An experimental investigation of surface static pressure distributions on octagonal cylinder in uniform and turbulent flows was carried out. The study was performed on both the single cylinder and the group of two cylinders, two cylinders were used, one was at the upstream side, and the other was at the downstream side of the flow. They were placed centrally along the flow direction. The inter-spacing space between the two cylinders was varied at 1D, 2D, 3D, 4D, 5D, 6D, 7D and 8D, where D is the width of the cylinder across the flow direction. The pressure coefficients were calculated from the measured values of the surface static pressure distribution on the cylinder. Then the drag and lift coefficients were obtained from the pressure coefficients by the numerical integration method. It was observed that at various angles of attack, the values of the lift coefficients and drag coefficients were insignificant compared to those for a sharp-edged square cylinder. The strength of the vortex shedding was shown to be reduced as the intensity of the incident turbulence was increased. Measurements of drag at various angles of attack (0° to 40° showed that with increase in turbulence level the minimum drag occurred at smaller values of angle of attack.

  20. Calculation of thermal stress condition in long metal cylinder under heating by continuous laser radiation

    International Nuclear Information System (INIS)

    Uglov, A.A.; Uglov, S.A.; Kulik, A.N.

    1997-01-01

    The method of determination of temperature field and unduced thermal stresses in long metallic cylinder under its heating by cw-laser normally distributed heat flux is offered. The graphically presented results of calculation show the stress maximum is placed behind of center of laser heat sport along its movement line on the cylinder surface

  1. 77 FR 37384 - High Pressure Steel Cylinders From the People's Republic of China: Countervailing Duty Order

    Science.gov (United States)

    2012-06-21

    ..., finish or coatings. Excluded from the scope of the order are high pressure steel cylinders manufactured... DEPARTMENT OF COMMERCE International Trade Administration [C-570-978] High Pressure Steel...''), the Department is issuing a countervailing duty order on high pressure steel cylinders (``steel...

  2. 77 FR 37377 - High Pressure Steel Cylinders From the People's Republic of China: Antidumping Duty Order

    Science.gov (United States)

    2012-06-21

    ... scope of the order are high pressure steel cylinders manufactured to UN-ISO-9809-1 and 2 specifications... DEPARTMENT OF COMMERCE International Trade Administration [A-570-977] High Pressure Steel... Department is issuing an antidumping duty order on high pressure steel cylinders from the People's Republic...

  3. The amplitude of fluid-induced vibration of cylinders in axial flow

    International Nuclear Information System (INIS)

    Paidoussis, M.P.

    1965-03-01

    This report describes a new empirical expression of the amplitude of transverse vibration of cylindrical beams and clusters of cylinders in axial flow, for application to reactor fuel. The expression is based on reported experimental observations covering a variety of geometries, cylinder materials and types of support in water, superheated steam and two-phase mixture flows. (author)

  4. SURFACE WAKE OF A CIRCULAR CYLINDER IN DILUTE AQUEOUS SOLUTIONS OF POLY(ETHYLENE OXIDE).

    Science.gov (United States)

    The wake formed by surface-piercing circular cylinders towed through 0, 100, and 200 parts per million (by weight) aqueous solutions of Poly( ethylene ... oxide ), Polyox WSR-301, was examined photographically. Cylinder diameters ranged from 1/4 in. to 2 in.; Froude numbers from 0.6 to 10. Measurements

  5. Background-oriented schlieren imaging of flow around a circular cylinder at low Mach numbers

    Science.gov (United States)

    Stadler, Hannes; Bauknecht, André; Siegrist, Silvan; Flesch, Robert; Wolf, C. Christian; van Hinsberg, Nils; Jacobs, Markus

    2017-09-01

    The background-oriented schlieren (BOS) imaging method has, for the first time, been applied in the investigation of the flow around a circular cylinder at low Mach numbers (Msuccessive imaging at incremental angular positions around the cylinder. This density distribution has been found to agree well with the pressure measurements and with potential theory where appropriate.

  6. Convective heat transfer from a heated elliptic cylinder at uniform wall temperature

    Energy Technology Data Exchange (ETDEWEB)

    Kaprawi, S.; Santoso, Dyos [Mechanical Department of Sriwijaya University, Jl. Raya Palembang-Prabumulih Km. 32 Inderalaya 50062 Ogan Ilir (Indonesia)

    2013-07-01

    This study is carried out to analyse the convective heat transfer from a circular and an elliptic cylinders to air. Both circular and elliptic cylinders have the same cross section. The aspect ratio of cylinders range 0-1 are studied. The implicit scheme of the finite difference is applied to obtain the discretized equations of hydrodynamic and thermal problem. The Choleski method is used to solve the discretized hydrodynamic equation and the iteration method is applied to solve the discretized thermal equation. The circular cylinder has the aspect ratio equal to unity while the elliptical cylinder has the aspect ratio less than unity by reducing the minor axis and increasing the major axis to obtain the same cross section as circular cylinder. The results of the calculations show that the skin friction change significantly, but in contrast with the elliptical cylinders have greater convection heat transfer than that of circular cylinder. Some results of calculations are compared to the analytical solutions given by the previous authors.

  7. Beating motion of a circular cylinder in vortex-induced vibrations

    Science.gov (United States)

    Shen, Linwei; Chan, Eng-Soon; Wei, Yan

    2018-04-01

    In this paper, beating phenomenon of a circular cylinder in vortex-induced vibration is studied by numerical simulations in a systematic manner. The cylinder mass coefficients of 2 and 10 are considered, and the Reynolds number is 150. Two distinctive frequencies, namely cylinder oscillation and vortex shedding frequencies, are obtained from the harmonic analysis of the cylinder displacement. The result is consistent with that observed in laboratory experiments. It is found that the cylinder oscillation frequency changes with the natural frequency of the cylinder while the reduced velocity is varied. The added-mass coefficient of the cylinder in beating motion is therefore estimated. Meanwhile, the vortex shedding frequency does not change dramatically in the beating situations. In fact, it is very close to 0.2. Accordingly, the lift force coefficient has two main components associated with these two frequencies. Besides, higher harmonics of the cylinder oscillation frequency appear in the spectrum of the lift coefficient. Moreover, the vortex shedding timing is studied in the beating motion by examining the instantaneous flow fields in the wake, and two scenarios of the vortex formation are observed.

  8. Effect of constant heat flux at outer cylinder on stability of viscous ...

    African Journals Online (AJOL)

    DR OKE

    However, in many chemical, electrical and mechanical engineering applications the temperature of both cylinders cannot remain the same. Thus, due to the change in the temperature of both cylinders, there exist a temperature gradient and the stability of the fluid flow is affected by the temperature gradient. The effects of a ...

  9. A Design to Digitalize Hydraulic Cylinder Control of a Machine Tool ...

    African Journals Online (AJOL)

    Conventionally hydraulic piston - cylinder servos are actuated using analogue controls for machine tool axis drives. In this paper a design of the axis control system of an NC milling machine which employs a small stepping motor to digitally actuated hydraulic piston - cylinder servo drives existing on the machines Y-axis is ...

  10. Criticality safety review of 2 1/2-, 10-, and 14-ton UF6 cylinders

    International Nuclear Information System (INIS)

    Broadhead, B.L.

    1991-10-01

    Currently, UF 6 cylinders designed to contain 2 1/2 tons of UF 6 are classified as Fissile Class 2 packages with a transport index (TI) of 5 for the purpose of transportation. The 10-ton UF 6 cylinders are classified as Fissile Class 1 with no TI assigned for transportation. The 14-ton cylinders, although not certified for transport with enrichments greater than 1 wt % because they have no approved overpack, can be used in on-site operations for enrichments greater than 1 wt %. The maximum 235 U enrichments for these cylinders are 5.0 wt % for the 2 1/2-ton cylinder and 4.5 wt % for the 10- and 14-ton cylinders. This work reviews the suitability for reclassification of the 2 1/2-ton UF 6 packages as Fissile Class 1 with a maximum 235 U enrichment of 5 wt %. Additionally, the 10- and 14-ton cylinders are reviewed to address a change in maximum 235 U enrichment from 4.5 to 5 wt %. Based on this evaluation, the 2 1/2-ton UF 6 cylinders meet the 10 CFR.71 criteria for Fissile Class 1 packages, and no TI is needed for criticality safety purposes; however, a TI may be required based on radiation from the packages. Similarly, the 10- and 14-ton UF 6 packages appear acceptable for a maximum enrichment rating change to 5 wt % 235 U. 11 refs., 13 figs., 7 tabs

  11. Characteristics of Sulfuric Acid Condensation on Cylinder Liners of Large Two-Stroke Marine Engines

    DEFF Research Database (Denmark)

    Cordtz, Rasmus Lage; Mayer, Stefan; Schramm, Jesper

    The present work seeks to clarify the characteristics of sulfuric acid condensation on the cylinder liner of a large two–stroke marine engine. The liner is directly exposed to the cylin-der gas (i.e. no protective lube oil film) and is represented by a constant temperature over the full stroke. F...

  12. Flow and Convective Heat Transfer of Cylinder Misaligned from Aerodynamic Axis of Cyclone Flow

    Directory of Open Access Journals (Sweden)

    I. L. Leukhin

    2008-01-01

    Full Text Available The paper provides and analyzes results of experimental investigations on physical specific features of hydrodynamics and convective heat transfer of a cyclone flow with a group of round cylinders located symmetrically relative to its aerodynamic axis, calculative equations for average and local heat transfer factors at characteristic sections of cylinder surface.

  13. Influence of the stacking sequence of layers on the mechanical behavior of polymeric composite cylinders

    International Nuclear Information System (INIS)

    Carvalho, Osni de

    2006-01-01

    This work evaluated experimentally the influence of the stacking sequence of layers symmetrical and asymmetrical on the mechanical behavior of polymeric composite cylinders. For so much, two open-ended cylinders groups were manufactured by filament winding process, which had different stacking sequence related to the laminate midplane, characterizing symmetrical and asymmetrical laminates. The composite cylinders were made with epoxy matrix and carbon fiber as reinforcement. For evaluation of the mechanical strength, the cylinders were tested hydrostatically, which consisted of internal pressurization in a hydrostatic device through the utilization of a fluid until the cylinders burst. Additionally, were compared the strains and failure modes between the cylinders groups. The utilization of a finite element program allowed to conclude that this tool, very used in design, does not get to identify tensions in the fiber direction in each composite layer, as well as interlaminar shear stress, that appears in the cylinders with asymmetrical stacking sequence. The tests results showed that the stacking sequence had influence in the mechanical behavior of the composite cylinders, favoring the symmetrical construction. (author)

  14. Effect of constant heat flux at outer cylinder on stability of viscous ...

    African Journals Online (AJOL)

    In this paper, the stability of the Couette flow of a viscous incompressible fluid between two concentric rotating cylinders is studied in the presence of a radial temperature gradient, when the outer cylinder is maintained at a constant heat flux. The analytical solution of the eigen-value problem is obtained by using the ...

  15. Effect of volume of solution per cylinder on estimation of antibiotic potency in diffusion assay.

    Science.gov (United States)

    Ragheb, H S

    1988-01-01

    The volume of antibiotic solutions in cylinders used for diffusion assays is assumed to have no significant effect on estimation of potency. The size of zones of inhibition from cylinders containing 0.10, 0.20, and 0.30 mL of sample solution was compared with zones of inhibition from cylinders containing 0.20 mL of standard solutions. For zinc bacitracin, chlortetracycline.HCl, oxytetracycline, lincomycin.HCl, monensin Na, neomycin sulfate, K penicillin, streptomycin sulfate, and tylosin, the percent recovery (95-102) was optimum when both standard and sample cylinders contained the same volume (0.20 mL/cylinder). At 0.30 mL/cylinder for sample and 0.20 mL for standard solutions, there was a positive bias in potency of about 50%. At 0.10 mL/cylinder, there was a negative bias of approximately 25% except for neomycin, monensin, and bacitracin. For these antibiotics, the bias was about -50%. For hygromycin B, variation in volume of solution per cylinder has little effect on assay results. Experiments on commercial feeds and premixes gave essentially the same results as for the standard solutions experiments.

  16. Localized surface plasmon modes in a system of two interacting metallic cylinders

    DEFF Research Database (Denmark)

    Babicheva, Viktoriia; Vergeles, Sergey S.; Vorobev, Petr E.

    2012-01-01

    We study an optical response of a system of two parallel close metallic cylinders having nanoscale dimensions. Surface plasmon excitation in the gap between the cylinders are specifically analyzed. In particular, resonance frequencies and field enhancement were investigated as functions of geomet...

  17. 77 FR 31551 - Hazardous Materials; Miscellaneous Amendments Pertaining to DOT Specification Cylinders (RRR)

    Science.gov (United States)

    2012-05-29

    ... accuracy, calibrated cylinder design requirements, and certain omissions. On July 17, 2009, CGA published... cylinders that served as a component of a kitchen fire suppression system and must use the proper shipping... technologies into the production and transportation stream. Federal hazmat law authorizes the Secretary to...

  18. Analysis of the magnetic field, force, and torque for two-dimensional Halbach cylinders

    DEFF Research Database (Denmark)

    Bjørk, Rasmus; Smith, Anders; Bahl, Christian Robert Haffenden

    2010-01-01

    for a two dimensional Halbach cylinder are derived. The remanent flux density of a Halbach magnet is characterized by the integer p. For a number of applications the force and torque between two concentric Halbach cylinders are important. These quantities are calculated and the force is shown to be zero...

  19. Development of Accept Reject Criteria for Requalification of High Pressure Steel and Aluminum Cylinders

    Science.gov (United States)

    Toughiry, M.

    2002-07-01

    Seamless steel cylinders that are used to transport high pressure gases are required to meet safety regulations promulgated by the U.S. Department of Transportation and other national authorities. As part of these safety regulations the cylinders are required to be periodically retested during their lifetime. This report describes a study where the performance of selected cylinders was evaluated based on the principals of structural integrity analysis. The effect of various types and sizes of flaws on the performance of seamless steel cylinders was evaluated by analytical modeling that was verified by using data from other studies which involved extensive testing of steel cylinders containing flaws. The API 579 Recommended Practice Fitness-for-Service methods of analysis were shown to reliably define the critical flaw sizes for flaws in seamless steel cylinders. Allowable flaw sizes can be established by calculating the amount of fatigue crack growth during the use of the cylinder using established fatigue crack growth data and analysis. The allowable flaw sizes are then used to set the acceptance levels for flaws at the time of inspection or retesting the cylinders.

  20. 49 CFR 180.205 - General requirements for requalification of specification cylinders.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false General requirements for requalification of... Cylinders § 180.205 General requirements for requalification of specification cylinders. (a) General. Each... subchapter. (b) Persons performing requalification functions. No person may represent that a repair or...