WorldWideScience

Sample records for sinusoidal tip growth

  1. Calcium homeostasis is required for contact-dependent helical and sinusoidal tip growth in Candida albicans hyphae

    OpenAIRE

    Brand, Alexandra; Lee, Keunsook; Veses, Veronica; Gow, Neil A R

    2009-01-01

    Hyphae of the dimorphic fungus, Candida albicans, exhibit directional tip responses when grown in contact with surfaces. On hard surfaces or in liquid media, the trajectory of hyphal growth is typically linear, with tip re-orientation events limited to encounters with topographical features (thigmotropism). In contrast, when grown on semisolid surfaces, the tips of C. albicans hyphae grow in an oscillatory manner to form regular two-dimensional sinusoidal curves and three-dimensional helices....

  2. Calcium homeostasis is required for contact-dependent helical and sinusoidal tip growth in Candida albicans hyphae.

    Science.gov (United States)

    Brand, Alexandra; Lee, Keunsook; Veses, Veronica; Gow, Neil A R

    2009-03-01

    Hyphae of the dimorphic fungus, Candida albicans, exhibit directional tip responses when grown in contact with surfaces. On hard surfaces or in liquid media, the trajectory of hyphal growth is typically linear, with tip re-orientation events limited to encounters with topographical features (thigmotropism). In contrast, when grown on semisolid surfaces, the tips of C. albicans hyphae grow in an oscillatory manner to form regular two-dimensional sinusoidal curves and three-dimensional helices. We show that, like thigmotropism, initiation of directional tip oscillation in C. albicans hyphae is severely attenuated when Ca2+ homeostasis is perturbed. Chelation of extracellular Ca2+ or deletion of the Ca2+ transporters that modulate cytosolic [Ca2+] (Mid1, Cch1 or Pmr1) did not affect hyphal length but curve formation was severely reduced in mid1Delta and cch1Delta and abolished in pmr1Delta. Sinusoidal hypha morphology was altered in the mid1Delta, chs3Delta and heterozygous pmr1Delta/PMR1 strains. Treatments that affect cell wall integrity, changes in surface mannosylation or the provision of additional carbon sources had significant but less pronounced effects on oscillatory growth. The induction of two- and three-dimensional sinusoidal growth in wild-type C. albicans hyphae is therefore the consequence of mechanisms that involve Ca2+ influx and signalling rather than gross changes in the cell wall architecture.

  3. Building a hair: tip growth in Arabidopsis thaliana root hairs.

    OpenAIRE

    Carol, Rachel J; Dolan, Liam

    2002-01-01

    The Arabidopsis thaliana root hair is used as a model for studying tip growth in plants. We review recent advances, made using physiological and genetic approaches, which give rise to different, yet compatible, current views of the establishment and maintenance of tip growth in epidermal cells. For example, an active calcium influx channel localized at the tip of Arabidopsis root hairs has been identified by patch-clamp measurements. Actin has been visualized in vivo in Arabidopsis root hairs...

  4. The cytoskeleton in plant and fungal cell tip growth

    NARCIS (Netherlands)

    Geitmann, A.; Emons, A.M.C.

    2000-01-01

    Tip-growing cells have a particular lifestyle that is characterized by the following features: (1) the cells grow in one direction, forming a cylindrical tube; (2) tip-growing cells are able to penetrate their growth environment, thus having to withstand considerable external forces; (3) the growth

  5. Building a hair: tip growth in Arabidopsis thaliana root hairs.

    Science.gov (United States)

    Carol, Rachel J; Dolan, Liam

    2002-06-29

    The Arabidopsis thaliana root hair is used as a model for studying tip growth in plants. We review recent advances, made using physiological and genetic approaches, which give rise to different, yet compatible, current views of the establishment and maintenance of tip growth in epidermal cells. For example, an active calcium influx channel localized at the tip of Arabidopsis root hairs has been identified by patch-clamp measurements. Actin has been visualized in vivo in Arabidopsis root hairs by using a green-fluorescent-protein-talin reporter and shown to form a dense mesh in the apex of the growing tip. The kojak gene, which encodes a protein similar to the catalytic subunit of cellulose synthase, is needed in the first stages of hair growth. A role for LRX1, a leucine-rich repeat extensin, in determining the morphology of the cell wall of root hairs has been established using reverse genetics. The new information can be integrated into a general and more advanced view of how these specialized plant cells grow.

  6. Iron assisted growth of copper-tipped multi-walled carbon nanotubes

    Science.gov (United States)

    Abrams, Z. R.; Szwarcman, D.; Lereah, Y.; Markovich, G.; Hanein, Y.

    2007-12-01

    Carbon nanotubes incorporating copper are highly sought after for nanoelectronic applications. Indeed, several recent studies have demonstrated the production of copper-tipped nanotubes using the chemical vapor deposition method. Here we present the growth and detailed characterization of such copper-tipped nanotubes. The nanotubes grown were of a 'bamboo-like' structure, consisting of stacked cups of graphene, and were produced by chemical vapor deposition employing iron and copper nanoparticles as a catalyst and metal source respectively. Transmission electron microscopy and electron holography analysis of the tips of these nanotubes revealed a small crystalline iron particle on the inner side of the copper tip, with the nanotube structure encapsulating the iron. This form of growth may allow the formation of similar structures with various other metal-tipped carbon nanotubes to be manufactured.

  7. Pollen tube and root-hair tip growth is disrupted in a mutant of Arabidopsis thaliana.

    Science.gov (United States)

    Schiefelbein, J; Galway, M; Masucci, J; Ford, S

    1993-11-01

    The expansion of both root hairs and pollen tubes occurs by a process known as tip growth. In this report, an Arabidopsis thaliana mutant (tip1) is described that displays defects in both root-hair and pollen-tube growth. The root hairs of the tip1 mutant plants are shorter than those of the wild-type plants and branched at their base. The tip1 pollen-tube growth defect was identified by the aberrant segregation ratio of phenotypically normal to mutant seeds in siliques from self-pollinated, heterozygous plants. Homozygous mutant seeds are not randomly distributed in the siliques, comprising only 14.4% of the total seeds, 5.3% of the seeds from the bottom half, and 2.2% of the seeds from the bottom quarter of the heterozygous siliques. Studies of pollen-tube growth in vivo showed that mutant pollen tubes grow more slowly than wild-type pollen through the transmitting tissue of wild-type flowers. Cosegregation studies indicate that the root-hair and pollen-tube defects are caused by the same genetic lesion. Based on these findings, the TIP1 gene is likely to encode a product involved in a fundamental aspect of tip growth in plant cells.

  8. Equivalence of the final stretch and crack tip opening angle criteria for plane strain crack growth

    International Nuclear Information System (INIS)

    Smith, E.

    1981-01-01

    The equivalence of the final stretch and crack tip opening angle criteria, as applied to the Dugdale-Bilby-Cottrell-Swinden type model for Mode I plane strain crack growth, is demonstrated. This equivalence is independent of the plastic zone size, geometrical parameters, and the stress distribution within the fracture process zone, if the yield stress is sufficiently low and the crack growth resistance is sufficiently high. The results therefore provide further support for the viability of crack tip opening angle as a crack growth chracterizing parameter. 7 refs

  9. Probing the effect of tip pressure on fungal growth: Application to Aspergillus nidulans

    Science.gov (United States)

    González-Bermúdez, Blanca; Li, Qingxuan; Guinea, Gustavo V.; Peñalva, Miguel A.; Plaza, Gustavo R.

    2017-08-01

    The study of fungal cells is of great interest due to their importance as pathogens and as fermenting fungi and for their appropriateness as model organisms. The differential pressure between the hyphal cytoplasm and the bordering medium is essential for the growth process, because the pressure is correlated with the growth rate. Notably, during the invasion of tissues, the external pressure at the tip of the hypha may be different from the pressure in the surrounding medium. We report the use of a method, based on the micropipette-aspiration technique, to study the influence of this external pressure at the hyphal tip. Moreover, this technique makes it possible to study hyphal growth mechanics in the case of very thin hyphae, not accessible to turgor pressure probes. We found a correlation between the local pressure at the tip and the growth rate for the species Arpergillus nidulans. Importantly, the proposed method allows one to measure the pressure at the tip required to arrest the hyphal growth. Determining that pressure could be useful to develop new medical treatments for fungal infections. Finally, we provide a mechanical model for these experiments, taking into account the cytoplasm flow and the wall deformation.

  10. On fatigue crack growth in ductile materials by crack-tip blunting

    DEFF Research Database (Denmark)

    Tvergaard, Viggo

    2004-01-01

    One of the basic mechanisms for fatigue crack growth in ductile metals is that depending on crack-tip blunting under tensile loads and re-sharpening of the crack-tip during unloading. In a standard numerical analysis accounting for finite strains it is not possible to follow this process during...... many cycles, as severe mesh distortion at the crack-tip results from the huge geometry changes developing during the cyclic plastic straining. In the present numerical studies, based on an elastic-perfectly plastic material model, crack growth computations are continued up to 200 full cycles by using...... remeshing at several stages of the plastic deformation. Three different values of the load ratio R = K-min/K-max are considered. It is shown that the crack-up opening displacement, CTOD, typically undergoes a transient behaviour, with no crack closure during many cycles, before a steady-state cycling...

  11. Nitrogen for growth of stock plants and production of strawberry runner tips

    Directory of Open Access Journals (Sweden)

    Djeimi Isabel Janisch

    2012-01-01

    Full Text Available The objective of this research was to determine growth and dry matter partitioning among organs of strawberry stock plants under five Nitrogen concentrations in the nutrient solution and its effects on emission and growth of runner tips. The experiment was carried out under greenhouse conditions, from September 2010 to March 2011, in a soilless system with Oso Grande and Camino Real cultivars. Nitrogen concentrations of 5.12, 7.6, 10.12 (control, 12.62 and 15.12 mmol L-1 in the nutrient solution were studied in a 5x2 factorial randomised experimental design. All runner tips bearing at least one expanded leaf (patent requested were collected weekly and counted during the growth period. The number of leaves, dry matter (DM of leaves, crown and root, specific leaf area and leaf area index (LAI was determined at the final harvest. Increasing N concentration in the nutrient solution from 5.12 to 15.12 mmol L-1 reduces growth of crown, roots and LAI of strawberry stock plants but did not affect emission and growth of runner tips. It was concluded that for the commercial production of plug plants the optimal nitrogen concentration in the nutrient solution should be 5.12 mmol L-1.

  12. Noise upon the Sinusoids

    DEFF Research Database (Denmark)

    Jensen, Karl Kristoffer

    2005-01-01

    Sinusoids are used for making harmonic and other sounds. In order to having life in the sounds and adding a wide variety of noises, irregularities are inserted in the frequency and amplitudes. A simple and intuitive noise model is presented, consisting of a low-pass filtered noise, and having...... control for strength and bandwidth. The noise is added on the frequency and amplitudes of the sinusoids, and the resulting irregularity’s (jitter and shimmer) bandwidth is derived. This, together with an overview of investigation methods of the jitter and shimmer results in an analysis of the necessary...

  13. Effect of biweekly shoot tip harvests on the growth and yield of Georgia Jet sweet potato grown hydroponically

    Science.gov (United States)

    Ogbuehi, Cyriacus R.; Loretan, Phil A.; Bonsi, C. K.; Hill, Walter A.; Morris, Carlton E.; Biswas, P. K.; Mortley, Desmond G.

    1989-01-01

    Sweet potato shoot tips have been shown to be a nutritious green vegetable. A study was conducted to determine the effect of biweekly shoot tip harvests on the growth and yield of Georgia Jet sweet potato grown in the greenhouse using the nutrient film technique (NFT). The nutrient solution consisted of a modified half Hoagland solution. Biweekly shoot tip harvests, beginning 42 days after planting, provided substantial amounts of vegetable greens and did not affect the fresh and dry foliage weights or the storage root number and fresh and dry storage root weights at final harvest. The rates of anion and cation uptake were not affected by tip harvests.

  14. EXO70C2 is a key regulatory factor for optimal tip growth of pollen

    KAUST Repository

    Synek, Lukas

    2017-03-30

    The exocyst, an eukaryotic tethering complex, co-regulates targeted exocytosis as an effector of small GTPases in polarized cell growth. In land plants, several exocyst subunits are encoded by double or triple paralogs, culminating in tens of EXO70 paralogs. Out of 23 Arabidopsis EXO70 isoforms, we analyzed seven isoforms expressed in pollen. Genetic and microscopic analyses of single mutants in EXO70A2, C1, C2, F1, H3, H5, and H6 genes revealed that only a loss-of-function EXO70C2 allele resulted in a significant male-specific transmission defect (segregation 40%:51%:9%) due to aberrant pollen tube growth. Mutant pollen tubes grown in vitro exhibited enhanced growth rate and a decreased thickness of the tip cell wall, causing tip bursts. However, exo70C2 pollen tubes could frequently recover and restart their speedy elongation, resulting in a repetitive stop-and-go growth dynamics. A pollen-specific depletion of the closest paralog, EXO70C1, using ami-RNA in the exo70C2 mutant background resulted in a complete pollen-specific transmission defect, suggesting redundant functions of EXO70C1 and EXO70C2. Both EXO70C1 and EXO70C2, GFP-tagged and expressed under their native promoters, localized in the cytoplasm of pollen grains, pollen tubes, and also root trichoblast cells. Expression of EXO70C2-GFP complemented aberrant growth of exo70C2 pollen tubes. The absent EXO70C2 interactions with core exocyst subunits in the yeast two-hybrid assay, cytoplasmic localization, and genetic effect suggest an unconventional EXO70 function possibly as a regulator of exocytosis outside the exocyst complex. In conclusion, EXO70C2 is a novel factor contributing to the regulation of optimal tip growth of Arabidopsis pollen tubes.

  15. A cyclic nucleotide-gated channel is essential for polarized tip growth of pollen.

    Science.gov (United States)

    Frietsch, Sabine; Wang, Yong-Fei; Sladek, Chris; Poulsen, Lisbeth R; Romanowsky, Shawn M; Schroeder, Julian I; Harper, Jeffrey F

    2007-09-04

    Ion signals are critical to regulating polarized growth in many cell types, including pollen in plants and neurons in animals. Genetic evidence presented here indicates that pollen tube growth requires cyclic nucleotide-gated channel (CNGC) 18. CNGCs are nonspecific cation channels found in plants and animals and have well established functions in excitatory signal transduction events in animals. In Arabidopsis, male sterility was observed for two cngc18 null mutations. CNGC18 is expressed primarily in pollen, as indicated from a promoter::GUS (beta-glucuronidase) reporter analysis and expression profiling. The underlying cause of sterility was identified as a defect in pollen tube growth, resulting in tubes that were kinky, short, often thin, and unable to grow into the transmitting tract. Expression of a GFP-tagged CNGC18 in mutant pollen provided complementation and evidence for asymmetric localization of CNGC18 to the plasma membrane at the growing tip, starting at the time of pollen grain germination. Heterologous expression of CNGC18 in Escherichia coli resulted in a time- and concentration-dependent accumulation of more Ca2+. Thus, CNGC18 provides a mechanism to directly transduce a cyclic nucleotide (cNMP) signal into an ion flux that can produce a localized signal capable of regulating the pollen tip-growth machinery. These results identify a CNGC that is essential to an organism's life cycle and raise the possibility that CNGCs have a widespread role in regulating cell-growth dynamics in both plant and animals.

  16. Growth of Pd-Filled Carbon Nanotubes on the Tip of Scanning Probe Microscopy

    Directory of Open Access Journals (Sweden)

    Tomokazu Sakamoto

    2009-01-01

    Full Text Available We have synthesized Pd-filled carbon nanotubes (CNTs oriented perpendicular to Si substrates using a microwave plasma-enhanced chemical vapor deposition (MPECVD for the application of scanning probe microscopy (SPM tip. Prior to the CVD growth, Al thin film (10 nm was coated on the substrate as a buffer layer followed by depositing a 5∼40 nm-thick Pd film as a catalyst. The diameter and areal density of CNTs grown depend largely on the initial Pd thickness. Scanning electron microscopy (SEM and transmission electron microscopy (TEM images clearly show that Pd is successfully encapsulated into the CNTs, probably leading to higher conductivity. Using optimum growth conditions, Pd-filled CNTs are successfully grown on the apex of the conventional SPM cantilever.

  17. Calcium-dependent protein kinases regulate polarized tip growth in pollen tubes.

    Science.gov (United States)

    Myers, Candace; Romanowsky, Shawn M; Barron, Yoshimi D; Garg, Shilpi; Azuse, Corinn L; Curran, Amy; Davis, Ryan M; Hatton, Jasmine; Harmon, Alice C; Harper, Jeffrey F

    2009-08-01

    Calcium signals are critical for the regulation of polarized growth in many eukaryotic cells, including pollen tubes and neurons. In plants, the regulatory pathways that code and decode Ca(2+) signals are poorly understood. In Arabidopsis thaliana, genetic evidence presented here indicates that pollen tube tip growth involves the redundant activity of two Ca(2+)-dependent protein kinases (CPKs), isoforms CPK17 and -34. Both isoforms appear to target to the plasma membrane, as shown by imaging of CPK17-yellow fluorescent protein (YFP) and CPK34-YFP in growing pollen tubes. Segregation analyses from two independent sets of T-DNA insertion mutants indicate that a double disruption of CPK17 and -34 results in an approximately 350-fold reduction in pollen transmission efficiency. The near sterile phenotype of homozygous double mutants could be rescued through pollen expression of a CPK34-YFP fusion. In contrast, a transgene rescue was blocked by mutations engineered to disrupt the Ca(2+)-activation mechanism of CPK34 (CPK34-YFP-E465A,E500A), providing in vivo evidence linking Ca(2+) activation to a biological function of a CPK. While double mutant pollen tubes displayed normal morphology, relative growth rates for the most rapidly growing tubes were reduced by more than three-fold compared with wild type. In addition, while most mutant tubes appeared to grow far enough to reach ovules, the vast majority (>90%) still failed to locate and fertilize ovules. Together, these results provide genetic evidence that CPKs are essential to pollen fitness, and support a mechanistic model in which CPK17 and -34 transduce Ca(2+) signals to increase the rate of pollen tube tip growth and facilitate a response to tropism cues.

  18. Sinusoidal Representation of Acoustic Signals

    Science.gov (United States)

    Honda, Masaaki

    Sinusoidal representation of acoustic signals has been an important tool in speech and music processing like signal analysis, synthesis and time scale or pitch modifications. It can be applicable to arbitrary signals, which is an important advantage over other signal representations like physical modeling of acoustic signals. In sinusoidal representation, acoustic signals are composed as sums of sinusoid (sine wave) with different amplitudes, frequencies and phases, which is based on the timedependent short-time Fourier transform (STFT). This article describes the principles of acoustic signal analysis/synthesis based on a sinusoid representation with focus on sine waves with rapidly varying frequency.

  19. Significance of power average of sinusoidal and non-sinusoidal ...

    Indian Academy of Sciences (India)

    Home; Journals; Pramana – Journal of Physics; Volume 87; Issue 1. Significance of power average of ... Additional sinusoidal and different non-sinusoidal periodic perturbations applied to the periodically forced nonlinear oscillators decide the maintainance or inhibitance of chaos. It is observed that the weak amplitude of ...

  20. A viscoplastic study of crack-tip deformation and crack growth in a nickel-based superalloy at elevated temperature

    Science.gov (United States)

    Zhao, L. G.; Tong, J.

    Viscoplastic crack-tip deformation behaviour in a nickel-based superalloy at elevated temperature has been studied for both stationary and growing cracks in a compact tension (CT) specimen using the finite element method. The material behaviour was described by a unified viscoplastic constitutive model with non-linear kinematic and isotropic hardening rules, and implemented in the finite element software ABAQUS via a user-defined material subroutine (UMAT). Finite element analyses for stationary cracks showed distinctive strain ratchetting behaviour near the crack tip at selected load ratios, leading to progressive accumulation of tensile strain normal to the crack-growth plane. Results also showed that low frequencies and superimposed hold periods at peak loads significantly enhanced strain accumulation at crack tip. Finite element simulation of crack growth was carried out under a constant Δ K-controlled loading condition, again ratchetting was observed ahead of the crack tip, similar to that for stationary cracks. A crack-growth criterion based on strain accumulation is proposed where a crack is assumed to grow when the accumulated strain ahead of the crack tip reaches a critical value over a characteristic distance. The criterion has been utilized in the prediction of crack-growth rates in a CT specimen at selected loading ranges, frequencies and dwell periods, and the predictions were compared with the experimental results.

  1. Pathology of the liver sinusoids

    NARCIS (Netherlands)

    Brunt, Elizabeth M.; Gouw, Annette S. H.; Hubscher, Stefan G.; Tiniakos, Dina G.; Bedossa, Pierre; Burt, Alastair D.; Callea, Francesco; Clouston, Andrew D.; Dienes, Hans P.; Goodman, Zachary D.; Roberts, Eve A.; Roskams, Tania; Terracciano, Luigi; Torbenson, Michael S.; Wanless, Ian R.

    The hepatic sinusoids comprise a complex of vascular conduits to transport blood from the porta hepatis to the inferior vena cava through the liver. Under normal conditions, portal venous and hepatic artery pressures are equalized within the sinusoids, oxygen and nutrients from the systemic

  2. SDN-1/syndecan regulates growth factor signaling in distal tip cell migrations in C. elegans.

    Science.gov (United States)

    Schwabiuk, Megan; Coudiere, Ludivine; Merz, David C

    2009-10-01

    Mutations in the sdn-1/syndecan gene act as genetic enhancers of the ventral-to-dorsal distal tip cell (DTC) migration defects caused by a weak allele of the netrin receptor gene unc-5. The sdn-1(ev697) allele was identified in a genetic screen for enhancers of unc-5 DTC migration defects, and carried a nonsense mutation predicted to truncate the SDN-1 protein prior to the transmembrane domain. The enhancement of unc-5 caused by an sdn-1 mutation was rescued by expression of wild-type sdn-1 in the hypodermis or nervous system rather than the DTCs, indicating a cell non-autonomous function of sdn-1. The enhancement was also partially reversed by mutations in the egl-17/FGF or egl-20/Wnt genes, suggesting that sdn-1 affects UNC-5 function through a mis-regulation of signaling in growth factor pathways. egl-20 reporter constructs exhibited increased and mis-localized EGL-20 distribution in sdn-1 mutants compared to wild-type animals. Finally, using loss of function mutations, we show that egl-17/Fgf and egl-20/Wnt are partially redundant in regulating the migration pattern of the posterior DTC, as double mutants exhibit significant frequencies of defects in migration phases along both the anteroposterior and dorsoventral axes. Together these results suggest that SDN-1 affects UNC-5 function by regulating the proper extracellular distribution of growth factors.

  3. Simultaneous angular alignment of segmented mirrors using sinusoidal pattern analysis

    Science.gov (United States)

    Choi, Heejoo; Trumper, Isaac; Dubin, Matthew; Zhao, Wenchuan; Kim, Dae Wook

    2017-08-01

    A segmented mirror is one of the most promising solutions to build an extremely large aperture telescope to reveal the secrets of the universe. In this manuscript, we present a simultaneous angle alignment method for segmented mirrors. By taking the displayed sinusoidal pattern reflecting off the mirrors, the tip-tilt angles are measured with 0.8 μrad resolution for a flat mirror. Due to the efficient calculation using Fourier analysis, the total measurement time for seven flat mirrors is 0.07 s. In addition, a multiplexed sinusoidal pattern is adapted to resolve the intrinsic 2π ambiguity problem in a sinusoidal signal. The presented method can measure any number of segmented mirrors provided that the camera's field of view can cover them all simultaneously.

  4. Sinusoids theory and technological applications

    CERN Document Server

    Kythe, Prem K

    2014-01-01

    A Complete Treatment of Current Research Topics in Fourier Transforms and Sinusoids Sinusoids: Theory and Technological Applications explains how sinusoids and Fourier transforms are used in a variety of application areas, including signal processing, GPS, optics, x-ray crystallography, radioastronomy, poetry and music as sound waves, and the medical sciences. With more than 200 illustrations, the book discusses electromagnetic force and sychrotron radiation comprising all kinds of waves, including gamma rays, x-rays, UV rays, visible light rays, infrared, microwaves, and radio waves. It also covers topics of common interest, such as quasars, pulsars, the Big Bang theory, Olbers' paradox, black holes, Mars mission, and SETI.The book begins by describing sinusoids-which are periodic sine or cosine functions-using well-known examples from wave theory, including traveling and standing waves, continuous musical rhythms, and the human liver. It next discusses the Fourier series and transform in both continuous and...

  5. Long-term benefits to the growth of ponderosa pines from controlling southwestern pine tip moth (Lepidoptera: Tortricidae) and weeds.

    Science.gov (United States)

    Wagner, Michael R; Chen, Zhong

    2004-12-01

    The southwestern pine tip moth, Rhyacionia neomexicana (Dyar) (Lepidoptera: Tortricidae), is a native forest pest that attacks seedlings and saplings of ponderosa pine, Pinus ponderosa Dougl. ex Laws, in the southwestern United States. Repeated attacks can cause severe deformation of host trees and significant long-term growth loss. Alternatively, effective control of R. neomexicana, vegetative competition, or both in young pine plantations may increase survival and growth of trees for many years after treatments are applied. We test the null hypothesis that 4 yr of R. neomexicana and weed control with insecticide, weeding, and insecticide plus weeding would not have any residual effect on survival and growth of trees in ponderosa pine plantation in northern Arizona 14 yr post-treatment, when the trees were 18 yr old. Both insecticide and weeding treatment increased tree growth and reduced the incidence of southwestern pine tip moth damage compared with the control. However, weeding alone also significantly increased tree survival, whereas insecticide alone did not. The insecticide plus weeding treatment had the greatest tree growth and survival, and the lowest rate of tip moth damage. Based on these results, we rejected our null hypothesis and concluded that there were detectable increases in the survival and growth of ponderosa pines 14 yr after treatments applied to control R. neomexicana and weeds.

  6. An evolutionarily conserved NIMA-related kinase directs rhizoid tip growth in the basal land plantMarchantia polymorpha.

    Science.gov (United States)

    Otani, Kento; Ishizaki, Kimitsune; Nishihama, Ryuichi; Takatani, Shogo; Kohchi, Takayuki; Takahashi, Taku; Motose, Hiroyasu

    2018-03-01

    Tip growth is driven by turgor pressure and mediated by the polarized accumulation of cellular materials. How a single polarized growth site is established and maintained is unclear. Here, we analyzed the function of NIMA-related protein kinase 1 (MpNEK1) in the liverwort Marchantia polymorpha In the wild type, rhizoid cells differentiate from the ventral epidermis and elongate through tip growth to form hair-like protrusions. In Mp nek1 knockout mutants, rhizoids underwent frequent changes in growth direction, resulting in a twisted and/or spiral morphology. The functional MpNEK1-Citrine protein fusion localized to microtubule foci in the apical growing region of rhizoids. Mp nek1 knockouts exhibited increases in both microtubule density and bundling in the apical dome of rhizoids. Treatment with the microtubule-stabilizing drug taxol phenocopied the Mp nek1 knockout. These results suggest that MpNEK1 directs tip growth in rhizoids through microtubule organization. Furthermore, MpNEK1 expression rescued ectopic outgrowth of epidermal cells in the Arabidopsis thaliana nek6 mutant, strongly supporting an evolutionarily conserved NEK-dependent mechanism of directional growth. It is possible that such a mechanism contributed to the evolution of the early rooting system in land plants. © 2018. Published by The Company of Biologists Ltd.

  7. Induction of contour sensing in Aspergillus niger by stress and its relevance to fungal growth mechanics and hyphal tip structure.

    Science.gov (United States)

    Bowen, Andrew D; Davidson, Fordyce A; Keatch, Robert; Gadd, Geoffrey M

    2007-06-01

    Thigmotropism (contour sensing) has been assigned an important role in both plant and human fungal pathogens. However, outside these systems, our knowledge of the function of thigmotropism in fungal growth control is relatively poor. Furthermore, the effects of environmental stress on thigmotropic responses have received scant attention. To try to elucidate some of the mechanisms behind hyphal contour sensing in response to nutrient-poor environments, we have used micro-engineered substrates and several imaging techniques to investigate the thigmotropic reactions of the ubiquitous fungus Aspergillus niger. This organism not appear to demonstrate thigmotropic growth under normal conditions. Our results show that A. niger undergoes significant morphological changes during growth on solid substrates and demonstrate that the intensity of contour sensing varies depending on the area of the hyphal tip which initiates contact with the substrate. We propose that growth under nutrient-limited conditions triggers several factors that combine to increase thigmotropic sensitivity while conversely creating a 60 degrees arc at the hyphal tip which is blind to topographical variations. This has important consequences for our general understanding of the hyphal mode of growth in fungi as well as more specific aspects of hyphal tip development under stress.

  8. Tip-Selective Growth of Silver on Gold Nanostars for Surface-Enhanced Raman Scattering.

    Science.gov (United States)

    Zhang, Weiqing; Liu, Jie; Niu, Wenxin; Yan, Heng; Lu, Xianmao; Liu, Bin

    2018-04-19

    Nanogaps as "hot spots" with highly localized surface plasmon can generate ultrastrong electromagnetic fields. Superior to the exterior nanogaps obtained via aggregation and self-assembly, interior nanogaps within Au and Ag nanostructures give stable and reproducible surface-enhanced Raman scattering (SERS) signals. However, the synthesis of nanostructures with interior hot spots is still challenging because of the lack of high-yield strategies and clear design principles. Herein, gold-silver nanoclusters (Au-Ag NCs) with multiple interior hot spots were fabricated as SERS platforms via selective growth of Ag nanoparticles on the tips of Au nanostars (Au NSs). Furthermore, the interior gap sizes of Au-Ag NCs can be facilely tuned by changing the amount of AgNO 3 used. Upon 785 nm excitation, single Au-Ag NC 350 exhibits 43-fold larger SERS enhancement factor and the optimal signal reproducibility relative to single Au NS. The SERS enhancement factors and signal reproducibility of Au-Ag NCs increase with the decrease of gap sizes. Collectively, the Au-Ag NCs could serve as a flexible, reproducible, and active platform for SERS investigation.

  9. Stress corrosion crack growth rates and general corrosion rates at crack tips of steels in high temperature water

    International Nuclear Information System (INIS)

    Speidel, M.O.; Magdowski, R.

    1995-01-01

    The maximum stress corrosion crack growth rates for a number of structural materials (steels and nickel alloys) have been measured in 288 C water. Also, the general corrosion rates of these materials have been determined from weight loss experiments in simulated stress corrosion crack tip electrolytes at 288 C. It is shown that the stress corrosion crack growth rates are typically twenty times faster than the general corrosion rates. This correlation holds over five orders of magnitude. It is concluded that strategies to prevent stress corrosion cracking in high temperature aqueous environments might include alloys of higher general corrosion resistance

  10. The sinusoid and the phasor

    OpenAIRE

    Shah, Kushal; Ramachandran, Harishankar

    2010-01-01

    Mathieu equation is widely used to study several natural phenomenon. In this paper, we show that replacing the sinusoid in the Mathieu equation with a phasor can lead to solutions that behave in a totally different way. Solutions of Mathieu equation are either bounded or grow unboundedly at an exponential rate. Solutions of this new equation are always unbounded and grow linearly with time.

  11. Comparison of HeNe laser and sinusoidal non-uniform magnetic field seed pre-sowing treatment effect on Glycine max (Var 90-I) germination, growth and yield.

    Science.gov (United States)

    Asghar, Tehseen; Iqbal, Munawar; Jamil, Yasir; Zia-Ul-Haq; Nisar, Jan; Shahid, Muhammad

    2017-01-01

    Recently, laser and magnetic field pre-sowing seed treatments attracted the attention of the scientific community in response to their positive effect on plant characteristics and the present study was exemplified for Glycine max Var 90-I. Seeds were exposed to laser (HeNe-wave length 632nm and density power of 1mW/cm 2 ) and magnetic field (sinusoidal non-uniform-50, 75 and 100mT for 3, 5min with exposure) and seed germination, seedling growth and yield attributes were compared. The germination (mean germination, germination percentage, emergence index, germination speed, relative germination coefficient, emergence coefficient of uniformity) growth (root dry weight, root length, shoot fresh weight and shoot dry weight, leaf dry & fresh weight, root fresh weight, leaf area, shoot length, plant total dry weight at different stages, stem diameter, number of leaves, vigor index I & II), biochemical (essential oil) and yield attributes (seed weight, count) were enhanced significantly in response to both laser and magnetic field treatments. However, magnetic field treatment furnished slightly higher response versus laser except relative water contents, whole plant weight and shoot length. Results revealed that both laser and magnetic field pre-sowing seed treatments affect the germination, seedling growth, and yield characteristics positively and could possibly be used to enhance Glycine max productivity. Copyright © 2016 Elsevier B.V. All rights reserved.

  12. Laser-induced asymmetric faceting and growth of a nano-protrusion on a tungsten tip

    Directory of Open Access Journals (Sweden)

    Hirofumi Yanagisawa

    2016-12-01

    Full Text Available Irradiation of a sharp tungsten tip by a femtosecond laser and exposed to a strong DC electric field led to reproducible surface modifications. By a combination of field emission microscopy and scanning electron microscopy, we observed asymmetric surface faceting with sub-ten nanometer high steps. The presence of faceted features mainly on the laser-exposed side implies that the surface modification was driven by a laser-induced transient temperature rise on a scale of a couple of picoseconds in the tungsten tip apex. Moreover, we identified the formation of a nano-tip a few nanometers high located at one of the corners of a faceted plateau. The results of simulations emulating the experimental conditions are consistent with the experimental observations. The presented technique would be a new method to fabricate a nano-tip especially for generating coherent electron pulses. The features may also help to explain the origin of enhanced field emission, which leads to vacuum arcs, in high electric field devices such as radio-frequency particle accelerators.

  13. Generation of Modified Sinusoidal Waves Using Operational ...

    African Journals Online (AJOL)

    The production of modified sinusoidal waves is currently a field of active research even in already developed countries as it combines the ease of production associated with square waves and avoids the low energy efficiency associated with true sinusoidal waves. This paper discusses the production of Modified Sinusoidal ...

  14. Expression of the citrus CsTIP2;1 gene improves tobacco plant growth, antioxidant capacity and physiological adaptation under stress conditions.

    Science.gov (United States)

    Martins, Cristina P S; Neves, Diana M; Cidade, Luciana C; Mendes, Amanda F S; Silva, Delmira C; Almeida, Alex-Alan F; Coelho-Filho, Mauricio A; Gesteira, Abelmon S; Soares-Filho, Walter S; Costa, Marcio G C

    2017-05-01

    Overexpression of the citrus CsTIP2;1 improves plant growth and tolerance to salt and drought stresses by enhancing cell expansion, H 2 O 2 detoxification and stomatal conductance. Tonoplast intrinsic proteins (TIPs) are a subfamily of aquaporins, belonging to the major intrinsic protein family. In a previous study, we have shown that a citrus TIP isoform, CsTIP2;1, is highly expressed in leaves and also transcriptionally regulated in leaves and roots by salt and drought stresses and infection by 'Candidatus Liberibacter asiaticus', the causal agent of the Huanglongbing disease, suggesting its involvement in the regulation of the flow of water and nutrients required during both normal growth and stress conditions. Here, we show that the overexpression of CsTIP2;1 in transgenic tobacco increases plant growth under optimal and water- and salt-stress conditions and also significantly improves the leaf water and oxidative status, photosynthetic capacity, transpiration rate and water use efficiency of plants subjected to a progressive soil drying. These results correlated with the enhanced mesophyll cell expansion, midrib aquiferous parenchyma abundance, H 2 O 2 detoxification and stomatal conductance observed in the transgenic plants. Taken together, our results indicate that CsTIP2;1 plays an active role in regulating the water and oxidative status required for plant growth and adaptation to stressful environmental conditions and may be potentially useful for engineering stress tolerance in citrus and other crop plants.

  15. The FEM based calculation of crack-tip strain rate for determining the crack growth rate of 304 stainless steel in BWR environments

    International Nuclear Information System (INIS)

    Lu, P.-C.

    2001-01-01

    This research calculates the crack growth rate (CGR) of the cooling pipe in the nuclear power plant. The crack is caused by the tension left in welding as well as by the coolant chemicals. There is, by far, no satisfactory deterministic model that can predict the crack growth rate. Although Macdonald's CEFM model is more close to a deterministic one, it requires accurate calculation of the crack-tip strain rate before the crack growth rate can be obtained by using Faraday's equation. The empirical equation used by the CEFM model for estimating the crack-tip strain rate is a drawback in making it a totally deterministic model. This research is set to make up this critical defect by applying non-linear finite element method to calculate the crack-tip strain rate. According to the metallic property, there is a plastic zone forming around the crack-tip. This research found when applying finite element method, the number of the elements (namely the mesh density) in the vicinity of the crack-tip has significant effects on the crack-tip strain obtained. Therefore, this research pioneered by using different mesh density in the vicinity of the crack-tip for the calculation of the crack-tip strain, the convergence of which is used for selecting the appropriate mesh density. The selected mesh density is then used to determine the dimension of the plastic zone, in which the crack-tip strain rate can be calculated. When the FEM results are compared with the experimental data, the nonlinear finite element method combined with CEFM shows a very satisfactory prediction capability

  16. Cosmology and the Sinusoidal Potential

    Science.gov (United States)

    Bartlett, David F.

    2006-06-01

    The nature of dark matter (and dark energy) remains a mystery. An alternative is being explored by several scientists: changing Newton's (and Einstein's) field equations. The sinusoidal potential is the latest attempt[1]. Here the gravitational law is alternately attractive and repulsive:φ = -GM cos(kor)/r, where λo=2π/ko = 1/20 of the distance from the sun to the center of the Milky Way. The proposal accommodates several structural features of the Milky Way including, paradoxically, its spiral shape and flat rotation curve. The sinusoidal potential's unique feature is strong galactic tidal forces (dg/dr). These may explain why the new planetoid Sedna is securely between the Kuiper Belt and the Oort cloud and why distant comets are more influenced by galactic tides that are in the r, rather than the z-direction.At this meeting I discuss the consequences of the sinusoidal potential for cosmology. Here the alternation of attraction and repulsion gives (i) an open universe, and (ii) gravitational lensing which is usually weak, but occasionally very strong. An open universe is one that, asymptotically, has a size R which varies directly as time t. The open universe conflicts both with the old Einstein-deSitter model (R α t2/3} and the new accelerating one. The evidence for an accelerating universe decisively rejects the Einstein-deSitter model. The rejection of an open (or empty) universe is less secure. This rejection is influenced by the different ways the groups studying the brightness of supernovae use the HST. Surprising additional inputs include neutrino masses, the equivalence principle, LSB galaxies, and "over-luminous" Sn1a. I thank Mostafa Jon Dadras and Patrick Motl for early help and John Cumalat for continual support. [1] D.F. Bartlett, "Analogies between electricity and gravity", Metrologia 41, S115-S124 (2004).

  17. The effect of creep damage formulation on crack tip fields, creep stress intensity factor and crack growth assessments

    Directory of Open Access Journals (Sweden)

    V. Shlyannikov

    2017-07-01

    Full Text Available Fields of stress, strain rate and process zone of a mode I creep crack growth are analyzed by employing damage evolution equations. Damage models for fracture of process zone represented by stress based formulation. Two expressions are presented to describe the stress-sensitive nature of multiaxial rupture behavior. Both damage free and defective creeping solids have been studied. The variation of creep stress and the crack-tip governing parameter in the form of creep In-integral with time and the evolution of creep damage were analyzed by using the FE-model. The effect of the introduced creep stress intensity factor as a function of creep time through the continuum damage mechanics of the creep crack growth are discussed in detail.

  18. Remembering tips

    Science.gov (United States)

    Memory aids; Alzheimer disease - remembering tips; Early memory loss - remembering tips; Dementia - remembering tips ... active: Read a lot if you have trouble remembering words. Keep a dictionary close by. Take part ...

  19. Tips for TIPS

    NARCIS (Netherlands)

    Cuijpers, C.F.

    2015-01-01

    The transjugular intrahepatic portosystemic shunt (TIPS) procedure is one of the most technically challenging procedures in interventional radiology. During the procedure, interventional radiologists (IRs) insert very thin and long instruments through a little incision in the patient’s neck. They

  20. Effect of Soil pH on Growth and Cation Deposition in the Root Tip of Zea mays L.

    Science.gov (United States)

    Walter; Silk; Schurr

    2000-03-01

    The effects of sandy soil pH on the distribution of growth velocities and on cation concentrations and deposition rates in root growth zones of Zea mays L. seedlings were investigated. The pH values of the rooting medium varied between 4.2 and 8.6 in sand culture (70% saturated) without external supply of nutrients. At all pH values, densities (in µmoles per g fresh weight) of potassium, magnesium, and calcium increased toward the root tip. Lower pH in the medium increased calcium tissue density fivefold and magnesium density 1.7-fold, whereas the density of potassium, the overall elongation rate, and the growth velocity distribution did not show any significant pH dependence. Throughout the growth zone the deposition rates of the divalent cations, as calculated on the basis of the continuity equation, increased with lower pH. The data are consistent with the hypothesis that the effects of pH on the cation deposition rates are due to the increase in the divalent cation concentration of the soil solution at low pH and that the abundant uronic acid residues of the young walls of the meristem provide a reservoir of storage capacity for Ca and Mg under conditions of low nutrient availability.

  1. Phytotoxic cyanamide affects maize (Zea mays) root growth and root tip function: from structure to gene expression.

    Science.gov (United States)

    Soltys, Dorota; Rudzińska-Langwald, Anna; Kurek, Wojciech; Szajko, Katarzyna; Sliwinska, Elwira; Bogatek, Renata; Gniazdowska, Agnieszka

    2014-05-01

    Cyanamide (CA) is a phytotoxic compound produced by four Fabaceae species: hairy vetch, bird vetch, purple vetch and black locust. Its toxicity is due to complex activity that involves the modification of both cellular structures and physiological processes. To date, CA has been investigated mainly in dicot plants. The goal of this study was to investigate the effects of CA in the restriction of the root growth of maize (Zea mays), representing the monocot species. CA (3mM) reduced the number of border cells in the root tips of maize seedlings and degraded their protoplasts. However, CA did not induce any significant changes in the organelle structure of other root cells, apart from increased vacuolization. CA toxicity was also demonstrated by its effect on cell cycle activity, endoreduplication intensity, and modifications of cyclins CycA2, CycD2, and histone HisH3 gene expression. In contrast, the arrangement of microtubules was not altered by CA. Treatment of maize seedlings with CA did not completely arrest mitotic activity, although the frequency of dividing cells was reduced. Furthermore, prolonged CA treatment increased the proportion of endopolyploid cells in the root tip. Cytological malformations were accompanied by an induction of oxidative stress in root cells, which manifested as enhanced accumulation of H2O2. Exposure of maize seedlings to CA resulted in an increased concentration of auxin and stimulated ethylene emission. Taken together, these findings suggested that the inhibition of root growth by CA may be a consequence of stress-induced morphogenic responses. Copyright © 2014. Published by Elsevier GmbH.

  2. Tip-induced domain growth on the non-polar cuts of lithium niobate single-crystals

    Science.gov (United States)

    Alikin, D. O.; Ievlev, A. V.; Turygin, A. P.; Lobov, A. I.; Kalinin, S. V.; Shur, V. Ya.

    2015-05-01

    Currently, ferroelectric materials with designed domain structures are considered as a perspective material for new generation of photonic, data storage, and data processing devices. Application of external electric field is the most convenient way of the domain structure formation. Lots of papers are devoted to the investigation of domain kinetics on polar surface of crystals while the forward growth remains one of the most mysterious stages due to lack of experimental methods allowing to study it. Here, we performed tip-induced polarization reversal on X- and Y-non-polar cuts in single-crystal of congruent lithium niobate which allows us to study the forward growth with high spatial resolution. The revealed difference in the shape and length of domains induced on X- and Y-cuts is beyond previously developed theoretical approaches used for the theoretical consideration of the domains growth at non-polar ferroelectric surfaces. To explain experimental results, we used kinetic approach with anisotropy of screening efficiency along different crystallographic directions.

  3. Geometric distortion correction for sinusoidally scanned images

    International Nuclear Information System (INIS)

    Xu, Lijun; Tian, Xiangrui; Li, Xiaolu; Shang, Guangyi; Yao, Junen

    2011-01-01

    A method for correcting the geometric distortion of sinusoidally scanned images was proposed. The generation mechanism of the geometric distortion in sinusoidally scanned images was analyzed. Based on the relationship between the coordinates of uniformly scanned points and those of sinusoidally scanned points, a transformation formula was obtained for correcting the geometric distortion when the sampling rate was a constant. By comparing the forward method with the inverse method, a hybrid method for correcting the geometric distortion of sinusoidally scanned images was proposed. This method takes advantage of both the forward and inverse methods and was proven to be better than either of them in terms of peak signal-to-noise ratio (PSNR). The time consumed by the hybrid method was between the other two. When a higher PSNR is desired, the hybrid method is recommended if time permits. In addition, it is a universal approach to the correction of geometric distortion of the images scanned in the sinusoidal mode

  4. Sinusoidal masks for single channel speech separation

    DEFF Research Database (Denmark)

    Mowlaee, Pejman; Christensen, Mads Græsbøll; Jensen, Søren Holdt

    2010-01-01

    In this paper we present a new approach for binary and soft masks used in single-channel speech separation. We present a novel approach called the sinusoidal mask (binary mask and Wiener filter) in a sinusoidal space. Theoretical analysis is presented for the proposed method, and we show that the......In this paper we present a new approach for binary and soft masks used in single-channel speech separation. We present a novel approach called the sinusoidal mask (binary mask and Wiener filter) in a sinusoidal space. Theoretical analysis is presented for the proposed method, and we show...... that the proposed method is able to minimize the target speech distortion while suppressing the crosstalk to a predetermined threshold. It is observed that compared to the STFTbased masks, the proposed sinusoidal masks improve the separation performance in terms of objective measures (SSNR and PESQ) and are mostly...

  5. Tipping Point

    Medline Plus

    Full Text Available ... death electrical fall furniture head injury product safety television tipover tv Watch the video in Adobe Flash ... tv tip-overs. The force of a large television falling from tipping furniture can be staggering. A ...

  6. Tipping Point

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    Full Text Available ... en español Blog About OnSafety CPSC Stands for Safety The Tipping Point Home > 60 Seconds of Safety (Videos) > The Tipping Point The Tipping Point by ... danger death electrical fall furniture head injury product safety television tipover tv Watch the video in Adobe ...

  7. Enhancing auxin accumulation in maize root tips improves root growth and dwarfs plant height.

    Science.gov (United States)

    Li, Zhaoxia; Zhang, Xinrui; Zhao, Yajie; Li, Yujie; Zhang, Guangfeng; Peng, Zhenghua; Zhang, Juren

    2018-01-01

    Maize is a globally important food, feed crop and raw material for the food and energy industry. Plant architecture optimization plays important roles in maize yield improvement. PIN-FORMED (PIN) proteins are important for regulating auxin spatiotemporal asymmetric distribution in multiple plant developmental processes. In this study, ZmPIN1a overexpression in maize increased the number of lateral roots and inhibited their elongation, forming a developed root system with longer seminal roots and denser lateral roots. ZmPIN1a overexpression reduced plant height, internode length and ear height. This modification of the maize phenotype increased the yield under high-density cultivation conditions, and the developed root system improved plant resistance to drought, lodging and a low-phosphate environment. IAA concentration, transport capacity determination and application of external IAA indicated that ZmPIN1a overexpression led to increased IAA transport from shoot to root. The increase in auxin in the root enabled the plant to allocate more carbohydrates to the roots, enhanced the growth of the root and improved plant resistance to environmental stress. These findings demonstrate that maize plant architecture can be improved by root breeding to create an ideal phenotype for further yield increases. © 2017 The Authors. Plant Biotechnology Journal published by Society for Experimental Biology and The Association of Applied Biologists and John Wiley & Sons Ltd.

  8. Tipping Point

    Medline Plus

    Full Text Available ... OnSafety CPSC Stands for Safety The Tipping Point Home > 60 Seconds of Safety (Videos) > The Tipping Point ... 24 hours a day. For young children whose home is a playground, it’s the best way to ...

  9. CPAP Tips

    Medline Plus

    Full Text Available ... a continuous positive airway pressure (CPAP) device when sleeping? Here are some tips from the U.S. Food ... 395,755 views 9:28 3 Tips for Sleeping With a CPAP - Duration: 2:02. WebMD 66, ...

  10. Encryption in Chaotic Systems with Sinusoidal Excitations

    Directory of Open Access Journals (Sweden)

    G. Obregón-Pulido

    2014-01-01

    Full Text Available In this contribution an encryption method using a chaotic oscillator, excited by “n” sinusoidal signals, is presented. The chaotic oscillator is excited by a sum of “n” sinusoidal signals and a message. The objective is to encrypt such a message using the chaotic behavior and transmit it, and, as the chaotic system is perturbed by the sinusoidal signal, the transmission security could be increased due to the effect of such a perturbation. The procedure is based on the regulation theory and consider that the receiver knows the frequencies of the perturbing signal, with this considerations the algorithm estimates the excitation in such a way that the receiver can cancel out the perturbation and all the undesirable dynamics in order to produce only the message. In this way we consider that the security level is increased.

  11. Cavitation on hydrofoils with sinusoidal leading edge

    Science.gov (United States)

    Johari, H.

    2015-12-01

    Cavitation characteristics of hydrofoils with sinusoidal leading edge were examined experimentally at a Reynolds number of 7.2 × 105. The hydrofoils had an underlying NACA 634-021 profile and an aspect ratio of 4.3. The sinusoidal leading edge geometries included three amplitudes of 2.5%, 5%, and 12% and two wavelengths of 25% and 50% of the mean chord length. Results revealed that cavitation on the leading edge-modified hydrofoils existed in pockets behind the troughs whereas the baseline hydrofoil produced cavitation along its entire span. Moreover, cavitation on the modified hydrofoils appeared at consistently lower angles of attack than on the baseline hydrofoil.

  12. Riding the Ferris Wheel: A Sinusoidal Model

    Science.gov (United States)

    Mittag, Kathleen Cage; Taylor, Sharon E.

    2011-01-01

    When thinking of models for sinusoidal waves, examples such as tides of the ocean, daily temperatures for one year in your town, light and sound waves, and certain types of motion are used. Many textbooks [1, p. 222] also present a "Ferris wheel description problem" for students to work. This activity takes the Ferris wheel problem out of the…

  13. Unidirectional Motion of Vehicle on Sinusoidal Path

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 17; Issue 4. Unidirectional Motion of Vehicle on Sinusoidal Path: Can it Cause Illusory Forward and Backward Motion? Anuj Bhatnagar. Classroom Volume 17 Issue 4 April 2012 pp 387-392 ...

  14. Sinusoidal cycling swimming pattern of reservoir fishes

    Czech Academy of Sciences Publication Activity Database

    Čech, Martin; Kubečka, Jan

    2002-01-01

    Roč. 61, č. 2 (2002), s. 456-471 ISSN 0022-1112 R&D Projects: GA AV ČR IAA6017901; GA AV ČR IAA6017201; GA ČR GA206/02/0520 Keywords : sinusoidal swimming * echosounder * reservoir Subject RIV: EH - Ecology, Behaviour Impact factor: 1.186, year: 2002

  15. Tipping Point

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    Full Text Available ... Point by CPSC Blogger September 22, 2009 appliance child Childproofing CPSC danger death electrical fall furniture head ... see news reports about horrible accidents involving young children and furniture, appliance and tv tip-overs. The ...

  16. CPAP Tips

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    Full Text Available ... make your opinion count. Sign in Loading... Loading... Transcript The interactive transcript could not be loaded. Loading... ... Dan Uses CPAP - Duration: 4:17. Harvard Medical School 7,950 views 4:17 Tips for building ...

  17. CPAP Tips

    Science.gov (United States)

    ... make your opinion count. Sign in Loading... Loading... Transcript The interactive transcript could not be loaded. Loading... ... Dan Uses CPAP - Duration: 4:17. Harvard Medical School 7,950 views 4:17 Tips for building ...

  18. Tipping Point

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    Full Text Available ... fall furniture head injury product safety television tipover tv Watch the video in Adobe Flash format. Almost ... accidents involving young children and furniture, appliance and tv tip-overs. The force of a large television ...

  19. Tipping Point

    Medline Plus

    Full Text Available ... impact can kill a child or cause severe injuries. About 16,000 (mostly young children) were treated in emergency rooms for tip-over related injuries in 2006, that’s about four times more injuries ...

  20. Tipping Point

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    Full Text Available ... appliance child Childproofing CPSC danger death electrical fall furniture head injury product safety television tipover tv Watch ... reports about horrible accidents involving young children and furniture, appliance and tv tip-overs. The force of ...

  1. Tipping Point

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    Full Text Available ... third story of a building. That kind of impact can kill a child or cause severe injuries. ... to prevent a tip-over tragedy. Share Post Facebook Twitter Google Plus Reddit Connect with Me:  Visit ...

  2. The Arabidopsis Phosphatidylinositol Phosphate 5-Kinase PIP5K3 is a key regulator of root hair tip growth

    NARCIS (Netherlands)

    Kusano, H.; Testerink, C.; Vermeer, J.E.M.; Tsuge, T.; Shimada, H.; Oka, A.; Munnik, T.; Aoyama, T.

    2008-01-01

    Phosphatidylinositol 4,5-bisphosphate [PtdIns(4,5)P2] functions as a site-specific signal on membranes to promote cytoskeletal reorganization and membrane trafficking. Localization of PtdIns(4,5)P2 to apices of growing root hairs and pollen tubes suggests that it plays an important role in tip

  3. Biphase sinusoidal oscillator based on negative resistor.

    Science.gov (United States)

    Bayard, Jean

    2010-06-01

    This paper describes a biphase sinusoidal generator which provides two signals: v(ref)=V(M) sin(omegat) and v(out)=V(M) sin(omegat+DeltaPhi), where DeltaPhi is in the range 0, pi/2 or -pi/2, 0 and is not dependent on the frequency value. It is based on a negative resistor and it requires very few components. SPICE simulations and measurements on an experimental setup confirm the theoretical analysis.

  4. Tipping Point

    Medline Plus

    Full Text Available ... 24 hours a day. For young children whose home is a playground, it’s the best way to prevent a tip-over tragedy. Share Post Facebook Twitter ... Security, and Legal Notice | Accessibility Policy | Open Government @ CPSC | ...

  5. CPAP Tips

    Medline Plus

    Full Text Available ... sleeping? Here are some tips from the U.S. Food and Drug Administration (FDA) on how to safely ... Copyright Creators Advertise Developers +YouTube Terms Privacy Policy & Safety Send feedback Test new features Loading... Working... Sign ...

  6. Regorafenib suppresses sinusoidal obstruction syndrome in rats.

    Science.gov (United States)

    Okuno, Masayuki; Hatano, Etsuro; Nakamura, Kojiro; Miyagawa-Hayashino, Aya; Kasai, Yosuke; Nishio, Takahiro; Seo, Satoru; Taura, Kojiro; Uemoto, Shinji

    2015-02-01

    Sinusoidal obstruction syndrome (SOS), a form of drug-induced liver injury related to oxaliplatin treatment, is associated with postoperative morbidity after hepatectomy. This study aimed to examine the impact of regorafenib, the first small-molecule kinase inhibitor to show efficacy against metastatic colorectal cancer, on a rat model of SOS. Rats with monocrotaline (MCT)-induced SOS were divided into two groups according to treatment with either regorafenib (6 mg/kg) or vehicle alone, which were administered at 12 and 36 h, respectively, before MCT administration. Histopathologic examination and serum biochemistry tests were performed 48 h after MCT administration. Sinusoidal endothelial cells were evaluated by immunohistochemistry and electron microscopy. To examine whether regorafenib preserved remnant liver function, a 30% hepatectomy was performed in each group. The rats in the vehicle group displayed typical SOS features, whereas these features were suppressed in the regorafenib group. The total SOS scores were significantly lower in the regorafenib group than in the vehicle group. Immunohistochemistry and electron microscopy showed that regorafenib had a protective effect on sinusoidal endothelial cells. The postoperative survival rate after 7 d was significantly better in the regorafenib group than that in the vehicle group (26.7% versus 6.7%, P Regorafenib reduced the phosphorylation of extracellular signal-regulated kinase, which induced matrix metalloproteinase-9 (MMP-9) activation and decreased the activity of MMP-9, one of the crucial mediators of SOS development. Regorafenib suppressed MCT-induced SOS, concomitant with attenuating extracellular signal-regulated kinase phosphorylation, and MMP-9 activation, suggesting that regorafenib may be a favorable agent for use in combination with oxaliplatin-based chemotherapy. Copyright © 2015 Elsevier Inc. All rights reserved.

  7. Tip enhancement

    CERN Document Server

    Kawata, Satoshi

    2007-01-01

    This book discusses the recent advances in the area of near-field Raman scattering, mainly focusing on tip-enhanced and surface-enhanced Raman scattering. Some of the key features covered here are the optical structuring and manipulations, single molecule sensitivity, analysis of single-walled carbon nanotubes, and analytic applications in chemistry, biology and material sciences. This book also discusses the plasmonic materials for better enhancement, and optical antennas. Further, near-field microscopy based on second harmonic generation is also discussed. Chapters have been written by some of the leading scientists in this field, who present some of their recent work in this field.·Near-field Raman scattering·Tip-enhanced Raman spectroscopy·Surface-enhanced Raman spectroscopy·Nano-photonics·Nanoanalysis of Physical, chemical and biological materials beyond the diffraction limits·Single molecule detection

  8. Surface wave propagation over sinusoidally varying topography: Theory and observation

    Science.gov (United States)

    Davies, A. G.; Heathershaw, A. D.

    Linear perturbation theory is used to show that the reflection coefficient of a patch of sinusoidal ripples on an otherwise flat bed is oscillatory in the quotient of the length of the patch and the surface wave length, and strongly dependent upon the quotient of the surface and bed wave numbers. Resonant interaction between the surface waves and the ripples if the surface wavenumber is half the ripple wavenumber is demonstrated. Few ripples, of relatively small steepness, are required to produce a substantial reflected wave. In resonant cases, the partially standing wave on the up-wave side of the ripple patch gives way, in an almost linear manner over the the ripple patch itself, to a progressive (transmitted) wave on the down-wave side. Wave tank data agree well with predictions, and suggest coupling between wave reflection and ripple growth on an erodible bed.

  9. Model selection and comparison for independents sinusoids

    DEFF Research Database (Denmark)

    Nielsen, Jesper Kjær; Christensen, Mads Græsbøll; Jensen, Søren Holdt

    2014-01-01

    In the signal processing literature, many methods have been proposed for estimating the number of sinusoidal basis functions from a noisy data set. The most popular method is the asymptotic MAP criterion, which is sometimes also referred to as the BIC. In this paper, we extend and improve this me....... Through simulations, we demonstrate that the lp-BIC outperforms the asymptotic MAP criterion and other state of the art methods in terms of model selection, de-noising and prediction performance. The simulation code is available online.......In the signal processing literature, many methods have been proposed for estimating the number of sinusoidal basis functions from a noisy data set. The most popular method is the asymptotic MAP criterion, which is sometimes also referred to as the BIC. In this paper, we extend and improve...... this method by considering the problem in a full Bayesian framework instead of the approximate formulation, on which the asymptotic MAP criterion is based. This leads to a new model selection and comparison method, the lp-BIC, whose computational complexity is of the same order as the asymptotic MAP criterion...

  10. New Approaches for Channel Prediction Based on Sinusoidal Modeling

    Directory of Open Access Journals (Sweden)

    Ekman Torbjörn

    2007-01-01

    Full Text Available Long-range channel prediction is considered to be one of the most important enabling technologies to future wireless communication systems. The prediction of Rayleigh fading channels is studied in the frame of sinusoidal modeling in this paper. A stochastic sinusoidal model to represent a Rayleigh fading channel is proposed. Three different predictors based on the statistical sinusoidal model are proposed. These methods outperform the standard linear predictor (LP in Monte Carlo simulations, but underperform with real measurement data, probably due to nonstationary model parameters. To mitigate these modeling errors, a joint moving average and sinusoidal (JMAS prediction model and the associated joint least-squares (LS predictor are proposed. It combines the sinusoidal model with an LP to handle unmodeled dynamics in the signal. The joint LS predictor outperforms all the other sinusoidal LMMSE predictors in suburban environments, but still performs slightly worse than the standard LP in urban environments.

  11. Amplitude Modulated Sinusoidal Signal Decomposition for Audio Coding

    DEFF Research Database (Denmark)

    Christensen, M. G.; Jacobson, A.; Andersen, S. V.

    2006-01-01

    In this paper, we present a decomposition for sinusoidal coding of audio, based on an amplitude modulation of sinusoids via a linear combination of arbitrary basis vectors. The proposed method, which incorporates a perceptual distortion measure, is based on a relaxation of a nonlinear least......-squares minimization. Rate-distortion curves and listening tests show that, compared to a constant-amplitude sinusoidal coder, the proposed decomposition offers perceptually significant improvements in critical transient signals....

  12. Compressed Domain Packet Loss Concealment of Sinusoidally Coded Speech

    DEFF Research Database (Denmark)

    Rødbro, Christoffer A.; Christensen, Mads Græsbøll; Andersen, Søren Vang

    2003-01-01

    We consider the problem of packet loss concealment for voice over IP (VoIP). The speech signal is compressed at the transmitter using a sinusoidal coding scheme working at 8 kbit/s. At the receiver, packet loss concealment is carried out working directly on the quantized sinusoidal parameters......, based on time-scaling of the packets surrounding the missing ones. Subjective listening tests show promising results indicating the potential of sinusoidal speech coding for VoIP....

  13. Sinusoidal Order Estimation Using Angles between Subspaces

    Directory of Open Access Journals (Sweden)

    Søren Holdt Jensen

    2009-01-01

    Full Text Available We consider the problem of determining the order of a parametric model from a noisy signal based on the geometry of the space. More specifically, we do this using the nontrivial angles between the candidate signal subspace model and the noise subspace. The proposed principle is closely related to the subspace orthogonality property known from the MUSIC algorithm, and we study its properties and compare it to other related measures. For the problem of estimating the number of complex sinusoids in white noise, a computationally efficient implementation exists, and this problem is therefore considered in detail. In computer simulations, we compare the proposed method to various well-known methods for order estimation. These show that the proposed method outperforms the other previously published subspace methods and that it is more robust to the noise being colored than the previously published methods.

  14. Stochastic analysis/synthesis using sinusoidal atoms

    DEFF Research Database (Denmark)

    Jensen, Kristoffer

    2008-01-01

    This work proposes a method for re-synthesizing music for use in perceptual experiments regarding structural changes and in music creation. Atoms are estimated from music audio, modelled in a stochastic model, and re-synthesized from the model pa- rameters. The atoms are found by splitting...... sinusoids into short segments, and modelled into amplitude and envelope shape, frequency, time and duration. A simple model for creating envelopes with percussive, sustained or crescendo shape is presented. Single variable and joint probability density functions are created from the atom parameters and used...... to re-create sounds with the same distribution of the atoms parameters. A novel method for visualization music, the musigram, permits a better understanding of the re- synthesized sounds....

  15. SHRIMP (CRANGON-CRANGON L) BROWSING UPON SIPHON TIPS INHIBITS FEEDING AND GROWTH IN THE BIVALVE MACOMA-BALTHICA (L)

    NARCIS (Netherlands)

    KAMERMANS, P; HUITEMA, HJ

    1994-01-01

    The influence of siphon browsing on the feeding behaviour and growth of Macoma balthica, a deposit-feeding bivalve, was studied in three manipulative experiments. Browsing was simulated by removing part of the inhalant siphon with scissors, or studied by exposing the bivalves to shrimps (Crangon

  16. Prom Health and Safety Tips

    Science.gov (United States)

    ... Autumn Tips Camping Tips Family Reunions Gardening Tips Halloween Tips Healthy Halloween Prom Tips Spring Break Valentine Tips Winter Holiday ... Breast Cancer Assess Your Relationships Be Safe on Halloween Be Smoke-Free Check Alarm Batteries Know Your ...

  17. Power Analysis of Traction Transformer under Non-Sinusoidal Conditions

    Directory of Open Access Journals (Sweden)

    Jaromir Kijonka

    2004-01-01

    Full Text Available Article deals with power analysis of traction transformer 100/27 kV, Sn= 10MVA under non-sinusoidal conditions. The power analysis is evaluated by means of IEEE Trial Use Standard Definitions of the Electric Power Quantities under Non-Sinusoidal Conditions, Document Number: IEEE 1459-2000.

  18. Parametric modeling for damped sinusoids from multiple channels

    DEFF Research Database (Denmark)

    Zhou, Zhenhua; So, Hing Cheung; Christensen, Mads Græsbøll

    2013-01-01

    The problem of parametric modeling for noisy damped sinusoidal signals from multiple channels is addressed. Utilizing the shift invariance property of the signal subspace, the number of distinct sinusoidal poles in the multiple channels is first determined. With the estimated number, the distinct...

  19. Variable Dimension Trellis-Coded Quantization of Sinusoidal Parameters

    DEFF Research Database (Denmark)

    Larsen, Morten Holm; Christensen, Mads G.; Jensen, Søren Holdt

    2008-01-01

    In this letter, we propose joint quantization of the parameters of a set of sinusoids based on the theory of trellis-coded quantization. A particular advantage of this approach is that it allows for joint quantization of a variable number of sinusoids, which is particularly relevant in variable...

  20. Tips for Daily Living

    Science.gov (United States)

    ... Tips and Gadgets for Daily Activities Dressing Tips Shopping Tips Modifying the Bathroom Driving After Stroke Medication ... and resources. Find a group in your area . Online Support If there is not a support group ...

  1. Quadratic sinusoidal analysis of voltage clamped neurons.

    Science.gov (United States)

    Magnani, Christophe; Moore, Lee E

    2011-11-01

    Nonlinear biophysical properties of individual neurons are known to play a major role in the nervous system, especially those active at subthreshold membrane potentials that integrate synaptic inputs during action potential initiation. Previous electrophysiological studies have made use of a piecewise linear characterization of voltage clamped neurons, which consists of a sequence of linear admittances computed at different voltage levels. In this paper, a fundamentally new theory is developed in two stages. First, analytical equations are derived for a multi-sinusoidal voltage clamp of a Hodgkin-Huxley type model to reveal the quadratic response at the ionic channel level. Second, the resulting behavior is generalized to a novel Hermitian neural operator, which uses an algebraic formulation capturing the entire quadratic behavior of a voltage clamped neuron. In addition, this operator can also be used for a nonlinear identification analysis directly applicable to experimental measurements. In this case, a Hermitian matrix of interactions is built with paired frequency probing measurements performed at specific harmonic and interactive output frequencies. More importantly, eigenanalysis of the neural operator provides a concise signature of the voltage dependent conductances determined by their particular distribution on the dendritic and somatic membrane regions of neurons. Finally, the theory is concretely illustrated by an analysis of an experimentally measured vestibular neuron, providing a remarkably compact description of the quadratic responses involved in the nonlinear processing underlying the control of eye position during head rotation, namely the neural integrator.

  2. Sinusoidal magnetic fields and chawki (silkworm) rearing in sericulture.

    Science.gov (United States)

    Qadri, S M H; Dhahira Beevi, N; Mani, A; Leelapriya, T; Dhilip, K S; Sanker Narayan, P V

    2006-01-01

    Effects of sinusoidal magnetic fields on chawki silkworm rearing have been studied. The experiment was conducted using a multi X Bi silkworm hybrid, PM x CSR 2. Disease-free layings were reared from hatching to cocooning and by subjecting first and second instar to three magnetic field frequencies: 0.1, 1.0, and 10 Hz at 1500 nT, pp, for six days at six hours per day. Controls were maintained simultaneously. Larval durations for both young-stage chawki (I and II) and late stage (III, IV, V) were calculated in days and hours, including the feeding and moulting periods for I to IV instars, and the feeding period for V instar up to the time of spinning. The study revealed that the magnetic exposures reduced both feeding and moulting times with no adverse effects on larval growth. The substantial reductions in time, 33 hours in instars I and II, and 64 hours in total larval duration, could be commercially important in chawki rearing, saving time, leaf consumption, and labor expenses.

  3. Asymptotic Theory of the Least Squares Estimators of Sinusoidal Signal

    National Research Council Canada - National Science Library

    Kundu, Debasis

    1997-01-01

    ... normality are derived for the sinusoidal signal under the assumption of normal error (Kundu; 1993) and under the assumptions of independent and identically distributed random variables in Kundu and Mitra...

  4. Converter for Measurement of non-sinusoidal current peak value

    DEFF Research Database (Denmark)

    Butvin, P.; Nielsen, Otto V; Brauer, Peter

    1997-01-01

    A linear-response toroid with core wound of rapidly quenched soft magnetic metallic ribbon and fitted with two windings is used to enable correct measurement of mean peak value of non-sinusoidal and not noise-free alternating current.......A linear-response toroid with core wound of rapidly quenched soft magnetic metallic ribbon and fitted with two windings is used to enable correct measurement of mean peak value of non-sinusoidal and not noise-free alternating current....

  5. On the relationship between endoreduplication and collet hair initiation and tip growth, as determined using six Arabidopsis thaliana root-hair mutants.

    Science.gov (United States)

    Sliwinska, Elwira; Mathur, Jaideep; Bewley, J Derek

    2015-06-01

    A positive correlation between nuclear DNA content and cell size, as postulated by the karyoplasmic theory, has been confirmed in many plant tissues. However, there is also evidence suggesting that there are exceptions. While in previous reports the cell size:ploidy relationship was studied in intact tissues containing cells of different sizes, here simultaneously developing single cells of collet hairs were used to study endoreduplication in Arabidopsis thaliana mutants that produce hairs of variable size and morphology. Endoreduplication in the root and collet zones of six different root-hair mutants was analysed before and after collet hair development using flow cytometry and confocal microscopy. Additionally, the changes in nuclear size (ploidy), shape, and movement in developing collet hairs of a hybrid between Arabidopsis transgenic line NLS-GFP-GUS and the rhd3 (root hair defective3) mutant were followed using time-lapse confocal microscopy. In this hybrid endoreduplication in the collet hairs was disturbed. However, based on the analyses of all mutants, no correlation was found between hair length and the ploidy of the cells in the collet and root regions. The results indicate that the karyoplasmic ratio is maintained at the beginning of collet-hair development, but tip growth proceeds in a DNA-amount-independent manner. The final size of a collet hair appears to be dependent more on genetic modifiers governing general cell physiology than on its DNA content. © The Author 2015. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For permissions, please email: journals.permissions@oup.com.

  6. Bayesian interpolation in a dynamic sinusoidal model with application to packet-loss concealment

    DEFF Research Database (Denmark)

    Nielsen, Jesper Kjær; Christensen, Mads Græsbøll; Cemgil, Ali Taylan

    2010-01-01

    In this paper, we consider Bayesian interpolation and parameter estimation in a dynamic sinusoidal model. This model is more flexible than the static sinusoidal model since it enables the amplitudes and phases of the sinusoids to be time-varying. For the dynamic sinusoidal model, we derive...

  7. Healthy Vision Tips

    Science.gov (United States)

    ... for Kids >> Healthy Vision Tips Listen All About Vision About the Eye Ask a Scientist Video Series ... Links to More Information Optical Illusions Printables Healthy Vision Tips Healthy vision starts with you! Use these ...

  8. Digestive Health Tips

    Science.gov (United States)

    ... Home / Digestive Health Topic / Digestive Health Tips Digestive Health Tips Basics 10 Tips on Belching, Bloating, and Flatulence Belching is caused by swallowed air from: Eating or drinking too fast Poorly fitting dentures; not chewing food completely Carbonated beverages Chewing gum or sucking on ...

  9. Transjugular Intrahepatic Portosystemic Shunt (TIPS): Current Status and Future Possibilities

    International Nuclear Information System (INIS)

    Bilbao, Jose Ignacio; Quiroga, Jorge; Herrero, Jose Ignacio; Benito, Alberto

    2002-01-01

    Since the insertion of the first TIPS in 1989 much has been learned about this therapeutic procedure. It has an established role for the treatment of some complications of portal hypertension: prevention of recurrent variceal bleeding and rescue of patients with acute uncontrollable variceal bleeding. In addition TIPS is useful for Budd-Chiari syndrome, refractory ascites and hepatorenal syndrome, although its specific role in these indications remains to be definitively established. However, the decrease in sinusoidal blood flow induced by TIPS can lead to the patient developing hepatic encephalopathy and liver failure in some cases. Therefore, TIPS should be used with caution in patients with very poor liver function. From a technical point of view, successful placement of TIPS is achieved in more than 98% of cases by experienced groups. At present, evaluation of TIPS dysfunction based on morphology probably leads to an overdiagnosis of this complication since most of these cases are not associated with clinical manifestations (recurrent bleeding or refractory ascites). The major disadvantage of TIPS remains its poor long-term patency requiring a mandatory surveillance program. The indicator for shunt function/malfunction should be the portosystemic pressure gradient, which is best assessed by intravascular measurements. Shunt obstructions may be prevented or reduced by the use of stent-grafts in the future

  10. Tip studies using CFD and comparison with tip loss models

    DEFF Research Database (Denmark)

    Hansen, Martin Otto Laver; Johansen, J.

    2004-01-01

    The flow past a rotating LM8.2 blade equipped with two different tips are computed using CFD. The different tip flows are analysed and a comparison with two different tip loss models is made. Keywords: tip flow, aerodynamics, CFD......The flow past a rotating LM8.2 blade equipped with two different tips are computed using CFD. The different tip flows are analysed and a comparison with two different tip loss models is made. Keywords: tip flow, aerodynamics, CFD...

  11. Production and propagation of Hermite-sinusoidal-Gaussian laser beams.

    Science.gov (United States)

    Tovar, A A; Casperson, L W

    1998-09-01

    Hermite-sinusoidal-Gaussian solutions to the wave equation have recently been obtained. In the limit of large Hermite-Gaussian beam size, the sinusoidal factors are dominant and reduce to the conventional modes of a rectangular waveguide. In the opposite limit the beams reduce to the familiar Hermite-Gaussian form. The propagation of these beams is examined in detail, and resonators are designed that will produce them. As an example, a special resonator is designed to produce hyperbolic-sine-Gaussian beams. This ring resonator contains a hyperbolic-cosine-Gaussian apodized aperture. The beam mode has finite energy and is perturbation stable.

  12. CNNs for sinusoidal signal recognition in hearing rehabilitation

    Science.gov (United States)

    Carnimeo, Leonarda; Giaquinto, Antonio

    2003-04-01

    In this paper, a contribution is given to provide a tool to the recognition of sinusoidal signals with a particular reference to the field of pediatric hearing rehabilitation. To this purpose, a synthesis technique previously developed by the authors' is used to design a Cellular Neural Network for an Associative Memory able to compare submitted discrete-time sinusoidal signals with memorized ones. A robustness analysis of the synthesized associative memory is also developed both for noisy inputs and for parameter variations. Simulation results are then reported to illustrate the performances of the designed network.

  13. The TIPS Liquidity Premium

    DEFF Research Database (Denmark)

    Andreasen, Martin Møller; Christensen, Jens H.E.; Simon Riddell, Simon

    We introduce an arbitrage-free term structure model of nominal and real yields that accounts for liquidity risk in Treasury inflation-protected securities (TIPS). The novel feature of our model is to identify liquidity risk from individual TIPS prices by accounting for the tendency that TIPS, like...... most fixed-income securities, go into buy-and-hold investors' portfolios as time passes. We find a sizable and countercyclical TIPS liquidity premium, which greatly helps our model in matching TIPS prices. Accounting for liquidity risk also improves the model's ability to forecast inflation and match...

  14. Arctic climate tipping points.

    Science.gov (United States)

    Lenton, Timothy M

    2012-02-01

    There is widespread concern that anthropogenic global warming will trigger Arctic climate tipping points. The Arctic has a long history of natural, abrupt climate changes, which together with current observations and model projections, can help us to identify which parts of the Arctic climate system might pass future tipping points. Here the climate tipping points are defined, noting that not all of them involve bifurcations leading to irreversible change. Past abrupt climate changes in the Arctic are briefly reviewed. Then, the current behaviour of a range of Arctic systems is summarised. Looking ahead, a range of potential tipping phenomena are described. This leads to a revised and expanded list of potential Arctic climate tipping elements, whose likelihood is assessed, in terms of how much warming will be required to tip them. Finally, the available responses are considered, especially the prospects for avoiding Arctic climate tipping points.

  15. Compressed Sensing Of Complex Sinusoids Off The Grid

    Science.gov (United States)

    Ping, Cheng; Liu, Shi; Jiaqun, Zhao

    2015-07-01

    To solve off-grid problem in compressed sensing, a new reconstruction algorithm for complex sinusoids is proposed. The compressed sensing reconstruction problem is transformed into a joint optimized problem. Based on coordinate descent approach and linear estimator, a new iteration algorithm is proposed. The results of experiments verify the effectiveness of the proposed method.

  16. Optimization for sinusoidal profiles in surface relief gratings ...

    Indian Academy of Sciences (India)

    2014-02-07

    Feb 7, 2014 ... filometry [7–9] and monitoring of surface self-diffusion of solids under ultrahigh vacuum conditions [10]. In the present work, recording parameters, i.e. exposure time and deve- lopment time for fabrication of such holographic gratings have been optimized to obtain nearly perfect sinusoidal profiles in the ...

  17. Harmonic analysis of DC capacitor current in sinusoidal and space ...

    Indian Academy of Sciences (India)

    triple-throw switch with the load terminal being the pole. The pole voltage vRO equals +0.5VDC, ... The harmonic content of the line current in a sinusoidally modulated NPC inverter is quite low when the switching ..... and the switching pulses for the switches SR2 and SR4 is generated by comparison with the bottom carrier.

  18. Optimization for sinusoidal profiles in surface relief gratings ...

    Indian Academy of Sciences (India)

    2014-02-07

    Feb 7, 2014 ... Astable sinusoidal pattern generated using a two-beam laser interferometric technique was recorded in thin films of positive photoresist deposited on glass substrates. Several gratings were generated by varying the exposure time of interference pattern and time of chemical development of exposed media.

  19. Sound waves in two-dimensional ducts with sinusoidal walls

    Science.gov (United States)

    Nayfeh, A. H.

    1974-01-01

    The method of multiple scales is used to analyze the wave propagation in two-dimensional hard-walled ducts with sinusoidal walls. For traveling waves, resonance occurs whenever the wall wavenumber is equal to the difference of the wavenumbers of any two duct acoustic modes. The results show that neither of these resonating modes could occur without strongly generating the other.

  20. Pelagic behaviour of reservoir fishes: sinusoidal swimming and associated behaviour

    OpenAIRE

    JAROLÍM, Oldřich

    2009-01-01

    Annotation Long-term fixed-location hydroacoustic study with uplooking transducer was performed during 2005 in Římov reservoir, Czech Republic. It dealt mainly with fish behaviour in the open water of reservoir, especially with sinusoidal swimming behaviour. The dependence of pelagic fish behaviour on environmental conditions was also studied.

  1. Using Antenna Arrays to Motivate the Study of Sinusoids

    Science.gov (United States)

    Becker, J. P.

    2010-01-01

    Educational activities involving antenna arrays to motivate the study of sinusoids are described. Specifically, using fundamental concepts related to phase and simple geometric arguments, students are asked to predict the location of interference nulls in the radiation pattern of two-element phased array antennas. The location of the radiation…

  2. Mechanical Behavior of Quasi-sinusoidal Corrugated Composite sheets

    Directory of Open Access Journals (Sweden)

    Pouyan Ghabezi

    2013-01-01

    Full Text Available An aircraft wing needs to display different mechanical behavior in different directions. 1- stiffness in the spanwise (transverse to the corrugation direction which enables the aerodynamic and inertial loads to be carried. 2- compliance in the chordwise (corrugation direction which would allow shape changes and increases in surface area; whereas a corrugated sheet due to their special geometry has potential to use in morphing applications. Therefore, in this paper the mechanical behaviour of quasi-sinusoidal corrugated composites is studied by commercial FEM software ABAQUS and a simple analytical model which is used for the initial stiffness of the quasi-sinusoidal corrugated composites (Yokozeki model. The elongation and effective stiffness in longitudinal and transverse directions of quasi-sinusoidal  corrugated  skins  and fat  composites  are  calculated  and  compared together.  Using  frst  and  second  Castigliano’s  theorem  and  Bernoulli-Euler  beam theorem can be used to calculate the defection and rotational angle of a beam (sheet. In this research, different dimensions of quasi-sinusoidal element for unidirectional and woven composites of E-glass/epoxy are investigated. FEM results and analytical model are compared together. Then, the analytical model is validated by experimental results of plain woven E-glass/epoxy composites. The results of FEM, experimental and analytical simulations show that how a corrugated composite can afford with certainty larger deformation than the fat composite in using this analytical model to predict the mechanical behavior of quasi-sinusoidal corrugated composites. It was found that the corrugated composites display extremely high anisotropic behavior and have high  tensile and fexural stiffness  in  transverse direction while exhibiting  low stiffness in longitudinal direction of corrugation.

  3. Nonlocal response functions for predicting shear flow of strongly inhomogeneous fluids. I. Sinusoidally driven shear and sinusoidally driven inhomogeneity.

    Science.gov (United States)

    Glavatskiy, Kirill S; Dalton, Benjamin A; Daivis, Peter J; Todd, B D

    2015-06-01

    We present theoretical expressions for the density, strain rate, and shear pressure profiles in strongly inhomogeneous fluids undergoing steady shear flow with periodic boundary conditions. The expressions that we obtain take the form of truncated functional expansions. In these functional expansions, the independent variables are the spatially sinusoidal longitudinal and transverse forces that we apply in nonequilibrium molecular-dynamics simulations. The longitudinal force produces strong density inhomogeneity, and the transverse force produces sinusoidal shear. The functional expansions define new material properties, the response functions, which characterize the system's nonlocal response to the longitudinal force and the transverse force. We find that the sinusoidal longitudinal force, which is mainly responsible for the generation of density inhomogeneity, also modulates the strain rate and shear pressure profiles. Likewise, we find that the sinusoidal transverse force, which is mainly responsible for the generation of sinusoidal shear flow, can also modify the density. These cross couplings between density inhomogeneity and shear flow are also characterized by nonlocal response functions. We conduct nonequilibrium molecular-dynamics simulations to calculate all of the response functions needed to describe the response of the system for weak shear flow in the presence of strong density inhomogeneity up to the third order in the functional expansion. The response functions are then substituted directly into the truncated functional expansions and used to predict the density, velocity, and shear pressure profiles. The results are compared to the directly evaluated profiles from molecular-dynamics simulations, and we find that the predicted profiles from the truncated functional expansions are in excellent agreement with the directly computed density, velocity, and shear pressure profiles.

  4. Nonlocal response functions for predicting shear flow of strongly inhomogeneous fluids. I. Sinusoidally driven shear and sinusoidally driven inhomogeneity

    Science.gov (United States)

    Glavatskiy, Kirill S.; Dalton, Benjamin A.; Daivis, Peter J.; Todd, B. D.

    2015-06-01

    We present theoretical expressions for the density, strain rate, and shear pressure profiles in strongly inhomogeneous fluids undergoing steady shear flow with periodic boundary conditions. The expressions that we obtain take the form of truncated functional expansions. In these functional expansions, the independent variables are the spatially sinusoidal longitudinal and transverse forces that we apply in nonequilibrium molecular-dynamics simulations. The longitudinal force produces strong density inhomogeneity, and the transverse force produces sinusoidal shear. The functional expansions define new material properties, the response functions, which characterize the system's nonlocal response to the longitudinal force and the transverse force. We find that the sinusoidal longitudinal force, which is mainly responsible for the generation of density inhomogeneity, also modulates the strain rate and shear pressure profiles. Likewise, we find that the sinusoidal transverse force, which is mainly responsible for the generation of sinusoidal shear flow, can also modify the density. These cross couplings between density inhomogeneity and shear flow are also characterized by nonlocal response functions. We conduct nonequilibrium molecular-dynamics simulations to calculate all of the response functions needed to describe the response of the system for weak shear flow in the presence of strong density inhomogeneity up to the third order in the functional expansion. The response functions are then substituted directly into the truncated functional expansions and used to predict the density, velocity, and shear pressure profiles. The results are compared to the directly evaluated profiles from molecular-dynamics simulations, and we find that the predicted profiles from the truncated functional expansions are in excellent agreement with the directly computed density, velocity, and shear pressure profiles.

  5. The sinusoidal lining cells in "normal" human liver. A scanning electron microscopic investigation

    DEFF Research Database (Denmark)

    Horn, T; Henriksen, Jens Henrik Sahl; Christoffersen, P

    1986-01-01

    The scanning electron microscopic was used to study the fenestrations of human liver sinusoids. Thirteen biopsies, where light microscopy and transmission electron microscopy revealed normal sinusoidal architecture, were investigated. The number of fenestrae was calculated in acinar zone 3...

  6. Tipping the balance: robustness of tip cell selection, migration and fusion in angiogenesis.

    Directory of Open Access Journals (Sweden)

    Katie Bentley

    2009-10-01

    Full Text Available Vascular abnormalities contribute to many diseases such as cancer and diabetic retinopathy. In angiogenesis new blood vessels, headed by a migrating tip cell, sprout from pre-existing vessels in response to signals, e.g., vascular endothelial growth factor (VEGF. Tip cells meet and fuse (anastomosis to form blood-flow supporting loops. Tip cell selection is achieved by Dll4-Notch mediated lateral inhibition resulting, under normal conditions, in an interleaved arrangement of tip and non-migrating stalk cells. Previously, we showed that the increased VEGF levels found in many diseases can cause the delayed negative feedback of lateral inhibition to produce abnormal oscillations of tip/stalk cell fates. Here we describe the development and implementation of a novel physics-based hierarchical agent model, tightly coupled to in vivo data, to explore the system dynamics as perpetual lateral inhibition combines with tip cell migration and fusion. We explore the tipping point between normal and abnormal sprouting as VEGF increases. A novel filopodia-adhesion driven migration mechanism is presented and validated against in vivo data. Due to the unique feature of ongoing lateral inhibition, 'stabilised' tip/stalk cell patterns show sensitivity to the formation of new cell-cell junctions during fusion: we predict cell fates can reverse. The fusing tip cells become inhibited and neighbouring stalk cells flip fate, recursively providing new tip cells. Junction size emerges as a key factor in establishing a stable tip/stalk pattern. Cell-cell junctions elongate as tip cells migrate, which is shown to provide positive feedback to lateral inhibition, causing it to be more susceptible to pathological oscillations. Importantly, down-regulation of the migratory pathway alone is shown to be sufficient to rescue the sprouting system from oscillation and restore stability. Thus we suggest the use of migration inhibitors as therapeutic agents for vascular

  7. Tips in Reading Instruction.

    Science.gov (United States)

    Ediger, Marlow

    Some tips can assist teachers in guiding each pupil to achieve more optimally, with respect to the ability to read well and reading comprehension. Among these 10 specific tips are: (1) teach individualized phonics in context; (2) assist the student to read in proper thought units by covering up words in sentences for clarification; (3) assist…

  8. ADHD: Tips to Try

    Science.gov (United States)

    ... Staying Safe Videos for Educators Search English Español ADHD: Tips to Try KidsHealth / For Teens / ADHD: Tips to Try Print en español TDAH: Consejos que puedes probar ADHD , short for attention deficit hyperactivity disorder , is a ...

  9. Total Telephone Tips.

    Science.gov (United States)

    Corder, Lloyd E.; And Others

    This manual of telephone behavior tips for business and sales professionals offers ways to handle the disgruntled caller and makes suggestions on topics relevant to the telephone. The manual is divided into the following sections and subsections: (1) Common Courtesy (staff tips, answering the telephone, screening calls, transferring calls, taking…

  10. Electric stimulation with sinusoids and white noise for neural prostheses

    Directory of Open Access Journals (Sweden)

    Daniel K Freeman

    2010-02-01

    Full Text Available We are investigating the use of novel stimulus waveforms in neural prostheses to determine whether they can provide more precise control over the temporal and spatial pattern of elicited activity as compared to conventional pulsatile stimulation. To study this, we measured the response of retinal ganglion cells to both sinusoidal and white noise waveforms. The use of cell-attached and whole cell patch clamp recordings allowed the responses to be observed without significant obstruction from the stimulus artifact. Electric stimulation with sinusoids elicited robust responses. White noise analysis was used to derive the linear kernel for the ganglion cell’s spiking response as well as for the underlying excitatory currents. These results suggest that in response to electric stimulation, presynaptic retinal neurons exhibit bandpass filtering characteristics with peak response that occur 25ms after onset. The experimental approach demonstrated here may be useful for studying the temporal response properties of other neurons in the CNS.

  11. Total harmonic distortion of an asymmetric quasi-sinusoidal current

    Directory of Open Access Journals (Sweden)

    Grebennikov Vitaliy

    2017-01-01

    Full Text Available This paper presents the correlation of factors that determine the quality of asymmetric quasi-sinusoidal output current and dynamic losses in the switches of the current generator circuit. The operating mode of the generator was obtained, especially of its power circuit elements, where combination of acceptable output current quality with relatively small dynamic losses in switches and mass-dimensional parameters of the inductor are provided. Achieved results can be used in designing this type of generators.

  12. Vibration Analysis of Composite Beams with Sinusoidal Periodically Varying Interfaces

    Science.gov (United States)

    Li, Botong; Liu, Chein-Shan; Zhu, Liangliang

    2017-12-01

    As an increasing variety of composite materials with complex interfaces are emerging, we develop a theory to investigate composite beams and shed some light on new physical insights into composite beams with sinusoidal periodically varying interfaces. For the natural vibration of composite beams with continuous or periodically varying interfaces, the governing equation has been derived according to the generalised Hamiltonian principle. For composite beams having different boundary conditions, we transform the governing equations into integral equations and solve them by using the sinusoidal functions as test functions as well as the basis of the vibration modes. Due to the orthogonality of the sinusoidal functions, expansion coefficients in closed form can be found. Therefore, the proposed iterative schemes, with the help of the Rayleigh quotient and boundary functions, can quickly find the eigenvalues and free vibration modes. The obtained natural frequencies agree well with those obtained using the finite element method. In addition, the proposed method can be extended easily to laminated composite beams in more general cases or complex components and geometries in vibration engineering. The effects of different material properties of the upper and lower components and varying interface geometry function on the frequency of the composite beams are examined. According to our investigation, the natural frequency of a laminated beam with a continuous or periodically varying interface can be changed by altering the density or elastic modulus. We also show the responses of the frequencies of the components to the varying periodic interface.

  13. Designing and Implementation of Stable Sinusoidal Rough-Neural Identifier.

    Science.gov (United States)

    Ahmadi, Ghasem; Teshnehlab, Mohammad

    2017-08-01

    A rough neuron is defined as a pair of conventional neurons that are called the upper and lower bound neurons. In this paper, the sinusoidal rough-neural networks (SR-NNs) are used to identify the discrete dynamic nonlinear systems (DDNSs) with or without noise in series-parallel configuration. In the identification of periodic nonlinear systems, sinusoidal activation functions provide more efficient neural networks than the sigmoidal activation functions. Based on the Lyapunov stability theory, an online learning algorithm is developed to train the SR-NNs. The asymptotically convergence of the identification error to zero and the boundedness of parameters as well as predictions are proved. SR-NNs are used to identify some DDNSs and the cement rotary kiln (CRK). CRK is a complex nonlinear system in the cement factory, which produces the cement clinker. The experiments show that the SR-NNs in the identification of nonlinear systems have better performances than multilayer perceptrons (MLPs), sinusoidal neural networks, and rough MLPs, particularly in the presence of noise.

  14. Increased sinusoidal volume and solute extraction during retrograde liver perfusion

    International Nuclear Information System (INIS)

    Bass, N.M.; Manning, J.A.; Weisiger, R.A.

    1989-01-01

    Retrograde isolated liver perfusion has been used to probe acinar functional heterogeneity, but the hemodynamic effects of backward flow have not been characterized. In this study, extraction of a long-chain fatty acid derivative, 12-N-methyl-7-nitrobenzo-2-oxa-1,3-diazol-amino stearate (12-NBDS), was greater during retrograde than during anterograde perfusion of isolated rat liver. To determine whether hemodynamic differences between anterograde and retrograde perfused livers could account for this finding, the hepatic extracellular space was measured for both directions of flow by means of [ 14 C]sucrose washout during perfusion as well as by direct measurement of [ 14 C]sucrose entrapped during perfusion. A three- to fourfold enlargement of the total hepatic extracellular space was found during retrograde perfusion by both approaches. Examination of perfusion-fixed livers by light microscopy and morphometry revealed that marked distension of the sinusoids occurred during retrograde perfusion and that this accounts for the observed increase in the [ 14 C]sucrose space. These findings support the hypothesis that maximum resistance to perfusate flow in the isolated perfused rat liver is located at the presinusoidal level. In addition, increased transit time of perfusate through the liver and greater sinusoidal surface area resulting from sinusoidal distension may account for the higher extraction of 12-NBDS and possibly other compounds by retrograde perfused liver

  15. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

    Medline Plus

    Full Text Available ... the liver). Portal hypertension can also occur in children, although children are much less likely to require a TIPS. ... intentionally to solve the problem. Although extremely rare, children may also require a TIPS procedure. TIPS in ...

  16. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

    Medline Plus

    Full Text Available ... vs. risks? What are the limitations of TIPS? What is a Transjugular Intrahepatic Portosystemic Shunt (TIPS)? A ... likely to require a TIPS. top of page What are some common uses of the procedure? A ...

  17. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

    Medline Plus

    Full Text Available ... pressure. top of page How does the procedure work? A TIPS reroutes blood flow in the liver ... TIPS is a minimally invasive procedure that typically has a shorter recovery time than surgery. Your TIPS ...

  18. The Relationship between Fenestrations, Sieve Plates and Rafts in Liver Sinusoidal Endothelial Cells

    Science.gov (United States)

    McNerney, Gregory P.; Owen, Dylan M.; Zencak, Dusan; Zykova, Svetlana N.; Crane, Harry; Huser, Thomas; Quinn, Ronald J.; Smedsrød, Bård; Le Couteur, David G.; Cogger, Victoria C.

    2012-01-01

    Fenestrations are transcellular pores in endothelial cells that facilitate transfer of substrates between blood and the extravascular compartment. In order to understand the regulation and formation of fenestrations, the relationship between membrane rafts and fenestrations was investigated in liver sinusoidal endothelial cells where fenestrations are grouped into sieve plates. Three dimensional structured illumination microscopy, scanning electron microscopy, internal reflectance fluorescence microscopy and two-photon fluorescence microscopy were used to study liver sinusoidal endothelial cells isolated from mice. There was an inverse distribution between sieve plates and membrane rafts visualized by structured illumination microscopy and the fluorescent raft stain, Bodipy FL C5 ganglioside GM1. 7-ketocholesterol and/or cytochalasin D increased both fenestrations and lipid-disordered membrane, while Triton X-100 decreased both fenestrations and lipid-disordered membrane. The effects of cytochalasin D on fenestrations were abrogated by co-administration of Triton X-100, suggesting that actin disruption increases fenestrations by its effects on membrane rafts. Vascular endothelial growth factor (VEGF) depleted lipid-ordered membrane and increased fenestrations. The results are consistent with a sieve-raft interaction, where fenestrations form in non-raft lipid-disordered regions of endothelial cells once the membrane-stabilizing effects of actin cytoskeleton and membrane rafts are diminished. PMID:23029409

  19. First Aid Tips

    Science.gov (United States)

    ... Program Diversity In Vision Research & Ophthalmology (DIVRO) Student Training Programs To search for current job openings visit HHS USAJobs Home » NEI for Kids » First Aid Tips Listen All About Vision About the Eye ...

  20. Tips for Daily Life

    Science.gov (United States)

    ... chapter Join our online community Tips for Daily Life Coping skills will help you handle day-to- ... challenges, maximize your independence and live a meaningful life with your diagnosis. Accepting changes Creating a coping ...

  1. Toilet training tips

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/patientinstructions/000944.htm Toilet training tips To use the sharing features on ... and 'pee'. Teaching Your Child to Use the Toilet Once your child is comfortable sitting on the ...

  2. Numerical analysis of beam with sinusoidally corrugated webs

    Science.gov (United States)

    Górecki, Marcin; Pieńko, Michał; Łagoda, GraŻyna

    2018-01-01

    The paper presents numerical tests results of the steel beam with sinusoidally corrugated web, which were performed in the Autodesk Algor Simulation Professional 2010. The analysis was preceded by laboratory tests including the beam's work under the influence of the four point bending as well as the study of material characteristics. Significant web's thickness and use of tools available in the software allowed to analyze the behavior of the plate girder as beam, and also to observe the occurrence of stresses in the characteristic element - the corrugated web. The stress distribution observed on the both web's surfaces was analyzed.

  3. Chaotic Dynamics of Red Blood Cells in a Sinusoidal Flow

    Science.gov (United States)

    Dupire, Jules; Abkarian, Manouk; Viallat, Annie

    2010-04-01

    We show that the motion of individual red blood cells in an oscillating moderate shear flow is described by a nonlinear system of three coupled oscillators. Our experiments reveal that the cell tank treads and tumbles either in a stable way with synchronized cell inclination, membrane rotation and hydrodynamic oscillations, or in an irregular way, very sensitively to initial conditions. By adapting our model described previously, we determine the theoretical diagram for the red cell motion in a sinusoidal flow close to physiological shear stresses and flow variation frequencies and reveal large domains of chaotic motions. Finally, fitting our observations allows a characterization of cell viscosity and membrane elasticity.

  4. The Casimir force for 2d sinusoidal gratings

    Directory of Open Access Journals (Sweden)

    Marachevsky Valery N.

    2016-01-01

    Full Text Available The Casimir free energy for 2d gratings separated by a vacuum slit is expressed in terms of Rayleigh coefficients, a novel general approach valid for arbitrary 2d surface profiles of gratings is outlined. The normal Casimir force in the system of two identical Si gratings with 2d sinusoidal surface profiles separated by a vacuum slit is computed for several amplitudes of surface profiles, distance dependence of the force is studied. A comparison with results for flat boundaries is performed.

  5. Monitoring sinusoidal vibration environments with a television system

    Energy Technology Data Exchange (ETDEWEB)

    Davis, J.W.; Anderson, F.O.; Lookabill, H.J.; Taylor, R.D.

    1975-02-01

    The development and prove-in work of this experiment established a technology for using television equipment to monitor hybrid microcircuits and other miniature assemblies in sinusoidal vibration environments. Production assemblies were run through sine vibration test sequences with television systems used to monitor the sequences. During the experiment different television lens systems were tried to obtain clean, sharp, highly magnified pictures of the assemblies being monitored. Successful monitoring of production assemblies during the experiment was accomplished, resulting in design changes to the assemblies and establishment of a television monitoring system.

  6. Adipogenesis: forces that tip the scales

    DEFF Research Database (Denmark)

    MacDougald, Ormond A; Mandrup, Susanne

    2001-01-01

    factors reviewed include Wnt, transforming growth factor beta, inflammatory cytokines and prostaglandin F(2alpha). Tipping the scales towards or away from adipogenesis has profound implications for human health. In this review, we describe recent contributions to the field and will focus on factors...

  7. Disproportionate abundance between ectomycorrhizal root tips and their associated mycelia

    DEFF Research Database (Denmark)

    Kjøller, Rasmus

    2006-01-01

    compared the ectomycorrhizal external mycelial community with the adjacent root-tip community in a Danish beech forest. Sand-filled in-growth mesh bags were used to trap external mycelia by incubating the mesh bags in the soil for 70 days. The adjacent ectomycorrhizal root-tip communities were recorded...

  8. Unusual spiral wave tip trajectories in a parametrically forced nonequilibrium system.

    Science.gov (United States)

    Lee, Jysoo; Kim, Jinha; Yi, Goen-hee; Lee, Kyoung J

    2002-04-01

    The effect of parametric modulations on spiral waves that form in a thin layer of liquid crystal under rotating magnetic field is studied in laboratory experiments and numerical simulations. Parametric forcings that are sinusoidal in time make a simply rotating spiral tip to meander, rendering a compound tip trajectory that is composed of a main circular orbit and a satellite orbit with an unusual crescent shape. No evidence of frequency locking is found. The underlying mechanism for the unusual shape of the satellite orbit is elucidated, and the dependence of the rotation frequency of the main circular orbit f(o) on the perturbation parameters are discussed.

  9. Hydraulic testing in granite using the sinusoidal variation of pressure

    International Nuclear Information System (INIS)

    Black, J.H.; Holmes, D.C.; Noy, D.J.

    1982-09-01

    Access to two boreholes at the Carwynnen test site in Cornwall enabled the trial of a number of innovative approaches to the hydrogeology of fractured crystalline rock. These methods ranged from the use of seisviewer data to measure the orientation of fractures to the use of the sinusoidal pressure technique to measure directional hydraulic diffusivity. The testing began with a short programme of site investigation consisting of borehole caliper and seisviewer logging followed by some single borehole hydraulic tests. The single borehole hydraulic testing was designed to assess whether the available boreholes and adjacent rock were suitable for testing using the sinusoidal method. The main testing methods were slug and pulse tests and were analysed using the fissured porous medium analysis proposed in Barker and Black (1983). Derived hydraulic conductivity (K) ranged from 2 x 10 -12 m/sec to 5 x 10 -7 m/sec with one near-surface zone of high K being perceived in both boreholes. The results were of the form which is typical of fractured rock and indicated a combination of high fracture frequency and permeable granite matrix. The results are described and discussed. (author)

  10. Propiedades de transporte de una superred de grafeno tipo sinusoidal

    Directory of Open Access Journals (Sweden)

    J. A. Briones-Torres

    2015-01-01

    Full Text Available En este trabajo usamos el método de la matriz de transferencia para estudiar el tunelamiento de los electrones de Dirac a través de superredes en grafeno. Consideramos una superred con potencial sinusoidal o polaridad invertida, para ello consideramos dos maneras de crearla, una por medio de sustratos mixtos junto con la aplicación de un campo perpendicular sobre el sustrato de Óxido de Silicio (SiO2, la otra por medio de potenciales alternados aplicados perpendicularmente sobre la sábana de grafeno. Calculamos las propiedades de transmisión, transporte y estructura electrónica, variando diferentes parámetros como ángulo de incidencia, anchos de pozos y barreras y diferente número de barreras. Se encontró (1 el importante papel que juega el efecto Klein en tales estructuras, (2 las propiedades de transmisión y transporte presentan cierta simetría respecto del origen de la energía, y (3 el carácter sinusoidal del sistema trae consigo una baja en el nivel de energía de las subbandas en el espectro de estados acotados, además las degenera y origina que la apertura-cierre de las minibandas sea en el mismo nivel de energía.

  11. Design and Optimization of Sinusoidal Formed Femur Prosthesis

    Directory of Open Access Journals (Sweden)

    Ahmet Zafer ŞENALP

    2015-01-01

    Full Text Available One of the major problems in hip replacement surgery is the hip replacement loosening. Hip replacement loosening occurs over time after the surgery and it is related to the discretization between the bone cement and prosthesis. The underlying factors of this situation are the stress occurring in the bone cement and the shape of the prosthesis. In this study, cortical and trabecular layers of the femur, bone cement and prosthesis were modeled. The models of bone cement and prosthesis were constructed parametrically and two different sinusoidal formed prostheses were developed unlike the former prostheses shapes. Analyses were conducted for these two different sinusoidal forms by using finite element method and optimization was conducted to obtain the appropriate prosthesis stem shape and bone cement thickness by using parametric modeling in finite element analyses. For finite element analyses and optimization, Ansys Workbench software was used and analyses were conducted for 316LS stainless steel material. Finally, the optimum prosthesis stem shape and bone cement thickness was determined by using the results of the analyses in the first stage

  12. Removal of Stationary Sinusoidal Noise from Random Vibration Signals.

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, Brian; Cap, Jerome S.

    2018-02-01

    In random vibration environments, sinusoidal line noise may appear in the vibration signal and can affect analysis of the resulting data. We studied two methods which remove stationary sine tones from random noise: a matrix inversion algorithm and a chirp-z transform algorithm. In addition, we developed new methods to determine the frequency of the tonal noise. The results show that both of the removal methods can eliminate sine tones in prefabricated random vibration data when the sine-to-random ratio is at least 0.25. For smaller ratios down to 0.02 only the matrix inversion technique can remove the tones, but the metrics to evaluate its effectiveness also degrade. We also found that using fast Fourier transforms best identified the tonal noise, and determined that band-pass-filtering the signals prior to the process improved sine removal. When applied to actual vibration test data, the methods were not as effective at removing harmonic tones, which we believe to be a result of mixed-phase sinusoidal noise.

  13. Three-dimensional tracking of plus-tips by lattice light-sheet microscopy permits the quantification of microtubule growth trajectories within the mitotic apparatus

    Science.gov (United States)

    Yamashita, Norio; Morita, Masahiko; Legant, Wesley R.; Chen, Bi-Chang; Betzig, Eric; Yokota, Hideo; Mimori-Kiyosue, Yuko

    2015-10-01

    Mitotic apparatus, which comprises hundreds of microtubules, plays an essential role in cell division, ensuring the correct segregation of chromosomes into each daughter cell. To gain insight into its regulatory mechanisms, it is essential to detect and analyze the behavior of individual microtubule filaments. However, the discrimination of discrete microtubule filaments within the mitotic apparatus is beyond the capabilities of conventional light microscopic technologies. Recently, we detected three-dimensional (3-D) microtubule growth dynamics within the cellular cytoplasmic space using lattice light-sheet microscopy in conjunction with microtubule growth marker protein end-binding 1, a microtubule plus-end-tracking protein, which was fused to green fluorescent protein (EB1-GFP). This technique enables high-resolution 3-D imaging at subsecond intervals. We adapted mathematical computing and geometric representation techniques to analyze spatial variations in microtubule growth dynamics within the mitotic spindle apparatus. Our analytical approach enabled the different dynamic properties of individual microtubules to be determined, including the direction and speed of their growth, and their growth duration within a 3-D spatial map. Our analysis framework provides an important step toward a more comprehensive understanding of the mechanisms driving cellular machinery at the whole-cell level.

  14. Improved linear ultrasonic motor performance with square-wave based driving-tip trajectory

    International Nuclear Information System (INIS)

    Le, Adam Y; Mills, James K; Benhabib, Beno

    2015-01-01

    This paper proposes the application of a non-sinusoidal periodic excitation voltage to induce a near-square-wave driving tip trajectory in linear ultrasonic motors (LUSMs). A square-wave-based trajectory can deliver superior frictional force to the moving stage in the forward stroke of the driving tip motion and reduced frictional force during the return stroke. This would reduce lost power in the periodic driving tip motion, thereby, increasing the output force and power of the LUSM. An implementation procedure is suggested to achieve the near-square-wave driving tip trajectory. The proposed approach is illustrated through realistic finite-element-based simulations using a bimodal LUSM configuration. (technical note)

  15. Construction of a liver sinusoid based on the laminar flow on chip and self-assembly of endothelial cells.

    Science.gov (United States)

    Mi, Shengli; Yi, Xiaoman; Du, Zhichang; Xu, Yuanyuan; Sun, Wei

    2018-02-20

    The liver is one of the main metabolic organs, and nearly all ingested drugs will be metabolized by the liver. Only a small fraction of drugs are able to come onto the market during drug development, and hepatic toxicity is a major cause for drug failure. Since drug development is costly in both time and materials, an in vitro liver model that can accelerate bioreactions in the liver and reduce drug consumption is imperative in the pharmaceutical industry. The liver on a chip is an ideal alternative for its controllable environment and tiny size, which means constructing a more biomimetic model, reducing material consumption as well as promoting drug diffusion and reaction. In this study, taking advantage of the laminar flow on chips and using natural degradable gel rat tail Collagen-I, we constructed a liver sinusoid on a chip. By synchronously injecting two kinds of cell-laden collagen, HepG2-laden collagen and HUVEC-laden collagen, we formed two collagen layers with a clear borderline. By controlling the HUVEC density and injection of growth factors, HUVECs in collagen formed a monolayer through self-assembly. Thus, a liver sinusoid on a chip was achieved in a more biomimetic environment with a more controllable and uniform distribution of discrete HUVECs. Viability, album secretion and urea synthesis of the live sinusoid on a chip were analysed on days 3, 5 and 7 after collagen injection with acetaminophen treatment at 0 (control), 10 and 20 mM. The results indicated that our liver sinusoid on a chip was able to maintain bioactivity and function for at least 7 d and was beneficial for hepatotoxic drug screening.

  16. Nitrogen for growth of stock plants and production of strawberry runner tips Nitrogênio para crescimento das plantas matrizes e produção de pontas de estolões de morangueiro

    Directory of Open Access Journals (Sweden)

    Djeimi Isabel Janisch

    2012-01-01

    Full Text Available The objective of this research was to determine growth and dry matter partitioning among organs of strawberry stock plants under five Nitrogen concentrations in the nutrient solution and its effects on emission and growth of runner tips. The experiment was carried out under greenhouse conditions, from September 2010 to March 2011, in a soilless system with Oso Grande and Camino Real cultivars. Nitrogen concentrations of 5.12, 7.6, 10.12 (control, 12.62 and 15.12 mmol L-1 in the nutrient solution were studied in a 5x2 factorial randomised experimental design. All runner tips bearing at least one expanded leaf (patent requested were collected weekly and counted during the growth period. The number of leaves, dry matter (DM of leaves, crown and root, specific leaf area and leaf area index (LAI was determined at the final harvest. Increasing N concentration in the nutrient solution from 5.12 to 15.12 mmol L-1 reduces growth of crown, roots and LAI of strawberry stock plants but did not affect emission and growth of runner tips. It was concluded that for the commercial production of plug plants the optimal nitrogen concentration in the nutrient solution should be 5.12 mmol L-1.O objetivo do trabalho foi determinar o crescimento e a partição de massa seca entre órgãos de plantas matrizes de morangueiro cultivadas sob cinco concentrações de (N nitrogênio na solução nutritiva e seu efeito na emissão e no crescimento de pontas de estolões. O experimento foi desenvolvido em ambiente protegido, de setembro de 2010 a março de 2011, em sistema de cultivo fora do solo com as cultivares Oso Grande e Camino Real. Foram estudadas concentrações de N de 5,12; 7,6; 10,12 (testemunha; 12,62 e 15.12 mmol L-1 na solução nutritiva em um esquema fatorial 5x2 em delineamento inteiramente casualizado. Todas as pontas de estolões emitidas com pelo menos uma folha expandida (patente requerida foram semanalmente coletadas e contadas durante todo o per

  17. Magnet pole tips

    Science.gov (United States)

    Thorn, Craig E.; Chasman, Chellis; Baltz, Anthony J.

    1984-04-24

    An improved magnet which more easily provides a radially increasing magnetic field, as well as reduced fringe field and requires less power for a given field intensity. The subject invention comprises a pair of spaced, opposed magnetic poles which further comprise a pair of pole roots, each having a pole tip attached to its center. The pole tips define the gap between the magnetic poles and at least a portion of each pole tip is separated from its associated pole root. The separation begins at a predetermined distance from the center of the pole root and increases with increasing radial distance while being constant with azimuth within that portion. Magnets in accordance with the subject invention have been found to be particularly advantageous for use in large isochronous cyclotrons.

  18. Effect of adenine sulphate interaction on growth and development of shoot regeneration and inhibition of shoot tip necrosis under in vitro condition in adult Syzygium cumini L.--a multipurpose tree.

    Science.gov (United States)

    Naaz, Afshan; Shahzad, Anwar; Anis, Mohammad

    2014-05-01

    An efficient method for cloning Syzygium cumini (above 40 years old) through mature nodal segments has been successfully developed and that could be exploited for large-scale production of this valuable multipurpose tree. Nodal segments from mature tree were taken as explants and cultured on MS basal medium with different cytokinins (BA, Kin, AdS). The application of BA proved to be the best responsive cytokinin for the induction of shoot buds and shoots, but the proliferated shoots exhibited slower and stunted growth accompanied with abscission of leaves and shoot tip necrosis (STN). The problem of leaf abscission and STN was considerably reduced by the application of an adjuvant, adenine sulphate (AdS) in the optimal medium which led to the production of a maximum of 14 shoots. Further improvement in shoot bud regeneration and improved growth pattern of the regenerating tissue was obtained on the media comprised of MS + BA (10 μM) + GA3 (2.5 μM). A total number of 15 shoots with mean shoot length of 5.9 cm was obtained. The healthy elongated shoots were then rooted on MS basal augmented with NAA (5 μM). The plantlets obtained were healthy and were successfully acclimatized and transferred under field condition with 70 % survival rate.

  19. Phonological awareness and sinusoidal amplitude modulation in phonological dislexia

    Directory of Open Access Journals (Sweden)

    Yolanda Peñaloza-López

    2016-04-01

    Full Text Available ABSTRACT Objective Dyslexia is the difficulty of children in learning to read and write as results of neurological deficiencies. The objective was to test the Phonological awareness (PA and Sinusoidal amplitude modulation (SAM threshold in children with Phonological dyslexia (PD. Methods We performed a case-control, analytic, cross sectional study. We studied 14 children with PD and 14 control children from 7 to 11 years of age, by means of PA measurement and by SAM test. The mean age of dyslexic children was 8.39 years and in the control group was 8.15. Results Children with PD exhibited inadequate skills in PA, and SAM. We found significant correlations between PA and SAM at 4 Hertz frequency, and calculated regression equations that predicts between one-fourth and one-third of variance of measurements. Conclusion Alterations in PA and SAM found can help to explain basis of deficient language processing exhibited by children with PD.

  20. Current and Voltage Mode Multiphase Sinusoidal Oscillators Using CBTAs

    Directory of Open Access Journals (Sweden)

    M. Sagbas

    2013-04-01

    Full Text Available Current-mode (CM and voltage-mode (VM multiphase sinusoidal oscillator (MSO structures using current backward transconductance amplifier (CBTA are proposed. The proposed oscillators can generate n current or voltage signals (n being even or odd equally spaced in phase. n+1 CBTAs, n grounded capacitors and a grounded resistor are used for nth-state oscillator. The oscillation frequency can be independently controlled through transconductance (gm of the CBTAs which are adjustable via their bias currents. The effects caused by the non-ideality of the CBTA on the oscillation frequency and condition have been analyzed. The performance of the proposed circuits is demonstrated on third-stage and fifth-stage MSOs by using PSPICE simulations based on the 0.25 µm TSMC level-7 CMOS technology parameters.

  1. Phonological awareness and sinusoidal amplitude modulation in phonological dislexia.

    Science.gov (United States)

    Peñaloza-López, Yolanda; Herrera-Rangel, Aline; Pérez-Ruiz, Santiago J; Poblano, Adrián

    2016-04-01

    Dyslexia is the difficulty of children in learning to read and write as results of neurological deficiencies. The objective was to test the Phonological awareness (PA) and Sinusoidal amplitude modulation (SAM) threshold in children with Phonological dyslexia (PD). We performed a case-control, analytic, cross sectional study. We studied 14 children with PD and 14 control children from 7 to 11 years of age, by means of PA measurement and by SAM test. The mean age of dyslexic children was 8.39 years and in the control group was 8.15. Children with PD exhibited inadequate skills in PA, and SAM. We found significant correlations between PA and SAM at 4 Hertz frequency, and calculated regression equations that predicts between one-fourth and one-third of variance of measurements. Alterations in PA and SAM found can help to explain basis of deficient language processing exhibited by children with PD.

  2. New Realizations of Single OTRA-Based Sinusoidal Oscillators

    Directory of Open Access Journals (Sweden)

    Hung-Chun Chien

    2014-01-01

    Full Text Available This study proposes three new sinusoidal oscillators based on an operational transresistance amplifier (OTRA. Each of the proposed oscillator circuits consists of one OTRA combined with a few passive components. The first circuit is an OTRA-based minimum RC oscillator. The second circuit is capable of providing independent control on the condition of oscillation without affecting the oscillation frequency. The third circuit exhibits independent control of oscillation frequency through a capacitor. This study first introduces the OTRA and the related formulations of the proposed oscillator circuits, and then discusses the nonideal effects, sensitivity analyses, and frequency stability of the presented circuits. The proposed oscillators exhibit low sensitivities and good frequency stability. Because the presented circuits feature low impedance output, they can be connected directly to the next stage without cascading additional voltage buffers. HSPICE simulations and experimental results confirm the feasibility of the new oscillator circuits.

  3. Ageing monitoring in IGBT module under sinusoidal loading

    DEFF Research Database (Denmark)

    Ghimire, Pramod; Pedersen, Kristian Bonderup; Rannestad, Bjørn

    2015-01-01

    until failure. The characterization at different stages of lifetime indicates that the rise in resistance originates from thermo-mechanical degradation of interconnects. Post-test investigations: four-point probing and micro-sectioning indicate thermo-mechanical induced degradation of the chip topside...... different ways: calibration of power modules after 24 h of operation, offline characterization every 5 min of operation, and continuous measurement during normal converter operation. Four power modules are tested, which are cycled to different degradation levels by number of cycles, where one is tested......This paper presents monitoring of ageing in high power insulated gate bipolar transistor (IGBT) modules subjected to sinusoidal loading at nominal power level. On-state voltage for IGBT, diode, and rise in interconnection resistance are used as ageing parameters. These are measured in three...

  4. Tips from the Classroom.

    Science.gov (United States)

    Wilhelm, Kim Hughes; Leverett, Thomas; Barrett, Rob J.; Chur-Hansen, Anna; Dantas-Whitney, Maria; Zapata, Gabriela; Garcia, Juan Felix

    1998-01-01

    Five articles present tips for rallying English-as-a-Second-Language students to the enterprise of creating context, tools, and language itself. The articles focus on using original dramas created by students, teaching nonnative English-speaking medical students to comprehend their patients' colloquial language, conducting research with native…

  5. Air Travel Health Tips

    Science.gov (United States)

    ... Conditions Prevention and Wellness Staying Healthy Healthy Living Travel Occupational Health First Aid and Injury Prevention Crisis ... MoreDepression in Children and TeensRead MoreBMI Calculator International Travel: Tips for Staying HealthyTexting and DrivingTravel Needs for ...

  6. 10 Data Visualization Tips

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

    Office 2004 Test Drive User

    communicated through the use of design choices. (as indicated in tip 8). 8. Use colour, size, and position to help the reader see what is important. Colour adds emphasis, highlights particular data points, and draws connections between graphs. The hue, value, and intensity of the colour are significant and may have cultural ...

  7. Sports Dehydration Safety Tips

    Science.gov (United States)

    Sports Dehydration Safety Tips Everything you need to know to keep your kids safe from dehydration when playing sports. To keep kids in top ... to stay hydrated by drinking plenty of fluids. Dehydration occurs when a body loses more water than ...

  8. Representative Sinusoids for Hepatic Four-Scale Pharmacokinetics Simulations.

    Directory of Open Access Journals (Sweden)

    Lars Ole Schwen

    Full Text Available The mammalian liver plays a key role for metabolism and detoxification of xenobiotics in the body. The corresponding biochemical processes are typically subject to spatial variations at different length scales. Zonal enzyme expression along sinusoids leads to zonated metabolization already in the healthy state. Pathological states of the liver may involve liver cells affected in a zonated manner or heterogeneously across the whole organ. This spatial heterogeneity, however, cannot be described by most computational models which usually consider the liver as a homogeneous, well-stirred organ. The goal of this article is to present a methodology to extend whole-body pharmacokinetics models by a detailed liver model, combining different modeling approaches from the literature. This approach results in an integrated four-scale model, from single cells via sinusoids and the organ to the whole organism, capable of mechanistically representing metabolization inhomogeneity in livers at different spatial scales. Moreover, the model shows circulatory mixing effects due to a delayed recirculation through the surrounding organism. To show that this approach is generally applicable for different physiological processes, we show three applications as proofs of concept, covering a range of species, compounds, and diseased states: clearance of midazolam in steatotic human livers, clearance of caffeine in mouse livers regenerating from necrosis, and a parameter study on the impact of different cell entities on insulin uptake in mouse livers. The examples illustrate how variations only discernible at the local scale influence substance distribution in the plasma at the whole-body level. In particular, our results show that simultaneously considering variations at all relevant spatial scales may be necessary to understand their impact on observations at the organism scale.

  9. Fibers comprised of epitaxially grown single-wall carbon nanotubes, and a method for added catalyst and continuous growth at the tip

    Science.gov (United States)

    Kittrell, W. Carter; Wang, Yuhuang; Kim, Myung Jong; Hauge, Robert H.; Smalley, Richard E.; Marek leg, Irene Morin

    2010-06-01

    The present invention is directed to fibers of epitaxially grown single-wall carbon nanotubes (SWNTs) and methods of making same. Such methods generally comprise the steps of: (a) providing a spun SWNT fiber; (b) cutting the fiber substantially perpendicular to the fiber axis to yield a cut fiber; (c) etching the cut fiber at its end with a plasma to yield an etched cut fiber; (d) depositing metal catalyst on the etched cut fiber end to form a continuous SWNT fiber precursor; and (e) introducing feedstock gases under SWNT growth conditions to grow the continuous SWNT fiber precursor into a continuous SWNT fiber.

  10. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

    Medline Plus

    Full Text Available ... TIPS. top of page What are some common uses of the procedure? A TIPS is used to ... the scanner by a cord. Some exams may use different transducers (with different capabilities) during a single ...

  11. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

    Medline Plus

    Full Text Available ... or bypass, without the risks that accompany open surgery. TIPS is a minimally invasive procedure that typically has a shorter recovery time than surgery. Your TIPS should have less of an effect ...

  12. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

    Medline Plus

    Full Text Available ... then placed in this tunnel to keep the pathway open. Patients who typically need a TIPS have ... and stomach. A TIPS procedure involves creating a pathway through the liver that connects the portal vein ( ...

  13. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

    Medline Plus

    Full Text Available ... and/or hydrothorax (in the chest). Budd-Chiari syndrome , a blockage in one or more veins that ... intentionally to solve the problem. Although extremely rare, children may also require a TIPS procedure. TIPS in ...

  14. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

    Medline Plus

    Full Text Available ... heart while avoiding the liver. TIPS may successfully reduce internal bleeding in the stomach and esophagus in ... TIPS reroutes blood flow in the liver and reduces abnormally high blood pressure in the veins of ...

  15. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

    Medline Plus

    Full Text Available ... What are the limitations of TIPS? What is a Transjugular Intrahepatic Portosystemic Shunt (TIPS)? A transjugular intrahepatic ... taking our brief survey: Survey Do you have a personal story about radiology? Share your patient story ...

  16. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

    Medline Plus

    Full Text Available ... liver disease are at greater risk for worsening liver failure after TIPS. If your liver failure is severe, a TIPS may not be the best use and a different procedure may be needed to control your symptoms. ... ordinarily filtered out by the liver. The TIPS may cause too much of these ...

  17. Tip-modified Propellers

    DEFF Research Database (Denmark)

    Andersen, Poul

    1999-01-01

    The paper deals with tip-modified propellers and the methods which, over a period of two decades, have been applied to develop such propellers. The development is driven by the urge to increase the efficiency of propellers and can be seen as analogous to fitting end plates and winglets to aircraft...... propeller, have efficiency increases of a reasonable magnitude in both open-water and behind-ship conditions....

  18. Sinusoidal oscillators and waveform generators using modern electronic circuit building blocks

    CERN Document Server

    Senani, Raj; Singh, V K; Sharma, R K

    2016-01-01

    This book serves as a single-source reference to sinusoidal oscillators and waveform generators, using classical as well as a variety of modern electronic circuit building blocks. It provides a state-of-the-art review of a large variety of sinusoidal oscillators and waveform generators and includes a catalogue of over 600 configurations of oscillators and waveform generators, describing their relevant design details and salient performance features/limitations. The authors discuss a number of interesting, open research problems and include a comprehensive collection of over 1500 references on oscillators and non-sinusoidal waveform generators/relaxation oscillators. Offers readers a single-source reference to everything connected to sinusoidal oscillators and waveform generators, using classical as well as modern electronic circuit building blocks; Provides a state-of-the-art review of a large variety of sinusoidal oscillators and waveform generators; Includes a catalog of over 600 configurations of oscillato...

  19. Orbital component extraction by time-variant sinusoidal modeling.

    Science.gov (United States)

    Sinnesael, Matthias; Zivanovic, Miroslav; De Vleeschouwer, David; Claeys, Philippe; Schoukens, Johan

    2016-04-01

    Accurately deciphering periodic variations in paleoclimate proxy signals is essential for cyclostratigraphy. Classical spectral analysis often relies on methods based on the (Fast) Fourier Transformation. This technique has no unique solution separating variations in amplitude and frequency. This characteristic makes it difficult to correctly interpret a proxy's power spectrum or to accurately evaluate simultaneous changes in amplitude and frequency in evolutionary analyses. Here, we circumvent this drawback by using a polynomial approach to estimate instantaneous amplitude and frequency in orbital components. This approach has been proven useful to characterize audio signals (music and speech), which are non-stationary in nature (Zivanovic and Schoukens, 2010, 2012). Paleoclimate proxy signals and audio signals have in nature similar dynamics; the only difference is the frequency relationship between the different components. A harmonic frequency relationship exists in audio signals, whereas this relation is non-harmonic in paleoclimate signals. However, the latter difference is irrelevant for the problem at hand. Using a sliding window approach, the model captures time variations of an orbital component by modulating a stationary sinusoid centered at its mean frequency, with a single polynomial. Hence, the parameters that determine the model are the mean frequency of the orbital component and the polynomial coefficients. The first parameter depends on geologic interpretation, whereas the latter are estimated by means of linear least-squares. As an output, the model provides the orbital component waveform, either in the depth or time domain. Furthermore, it allows for a unique decomposition of the signal into its instantaneous amplitude and frequency. Frequency modulation patterns can be used to reconstruct changes in accumulation rate, whereas amplitude modulation can be used to reconstruct e.g. eccentricity-modulated precession. The time-variant sinusoidal model

  20. Perception of the dynamic visual vertical during sinusoidal linear motion.

    Science.gov (United States)

    Pomante, A; Selen, L P J; Medendorp, W P

    2017-10-01

    The vestibular system provides information for spatial orientation. However, this information is ambiguous: because the otoliths sense the gravitoinertial force, they cannot distinguish gravitational and inertial components. As a consequence, prolonged linear acceleration of the head can be interpreted as tilt, referred to as the somatogravic effect. Previous modeling work suggests that the brain disambiguates the otolith signal according to the rules of Bayesian inference, combining noisy canal cues with the a priori assumption that prolonged linear accelerations are unlikely. Within this modeling framework the noise of the vestibular signals affects the dynamic characteristics of the tilt percept during linear whole-body motion. To test this prediction, we devised a novel paradigm to psychometrically characterize the dynamic visual vertical-as a proxy for the tilt percept-during passive sinusoidal linear motion along the interaural axis (0.33 Hz motion frequency, 1.75 m/s 2 peak acceleration, 80 cm displacement). While subjects ( n =10) kept fixation on a central body-fixed light, a line was briefly flashed (5 ms) at different phases of the motion, the orientation of which had to be judged relative to gravity. Consistent with the model's prediction, subjects showed a phase-dependent modulation of the dynamic visual vertical, with a subject-specific phase shift with respect to the imposed acceleration signal. The magnitude of this modulation was smaller than predicted, suggesting a contribution of nonvestibular signals to the dynamic visual vertical. Despite their dampening effect, our findings may point to a link between the noise components in the vestibular system and the characteristics of dynamic visual vertical. NEW & NOTEWORTHY A fundamental question in neuroscience is how the brain processes vestibular signals to infer the orientation of the body and objects in space. We show that, under sinusoidal linear motion, systematic error patterns appear in the

  1. Four-Wire Delta Service Sinusoidal Operation and Compensation Simulator

    Directory of Open Access Journals (Sweden)

    Vicente León-Martínez

    2015-10-01

    Full Text Available An off-line simulator based on Excel used to evaluate the operation of four-wire delta (4WD services as well as the effects of reactive and imbalance compensators in sinusoidal steady-state conditions is described in this paper. Voltages, currents and powers in the primary and secondary windings of the transformer as well as in the high voltage (HV and low voltage (LV lines and in the loads are calculated through that simulator. The apparent powers in the mains, transformer and loads are determined applying Buchholz’s and unified power measurement (UPM formulations in both scalar and vector notations. The effects of the neutral current are especially examined, in order to minimize them, and the optimal wye load distribution is determined by the simulator. The simulator provides the necessary elements of passive reactive and unbalanced compensators that optimize the 4WD transformer operation too. Those compensators are determined for each load, and they can be separately selected and included in the simulation process or not. An application example is finally used to step by step explain how the simulator runs.

  2. Magnetic field components in a sinusoidally varying helical wiggler

    Energy Technology Data Exchange (ETDEWEB)

    Caspi, S.

    1994-07-27

    One may be interested in a pure multipole magnetic field (i.e., proportional to sin(n{theta}) or cos(n{theta}) whose strength varies purely as a Fourier sinusoidal series of the longitudinal coordinate z (say proportional to cos{sub L}/{sup (2m-1){pi}z}), where L denotes the half-period of the wiggler and m=1,2,3{hor_ellipsis}). Associated with such a z variation, there necessarily will be presented a z component of magnetic field which in the source-free region, in fact, will give rise to both normal and skew transverse fields associated with the functions A{sub n}(z) and {Angstrom}{sub n}(z) as expressed in Reference{sup bc}. In this note the field components and expression for the scalar potential both inside and outside a thin pure winding surface are included with additional contributions from a possible high permeable shield. It is also shown that for a pure dipole case of n=1 and pure axial variation of m=1 the transverse field can be derived from a simple two dimensional field.

  3. Response of rat skin flaps to sinusoidal electromagnetic fields

    International Nuclear Information System (INIS)

    Herbst, E.

    1987-01-01

    Electrical stimulation to heal bone fractures has been used clinically since the early 1970s. As a result of treatment with either direct current or electromagnetic fields, there was an indication that the electrical signals enhanced the ingrowth of blood vessels into the treated area. This possibility was one of the reasons for the initial studies on the influence of pulsed electromagnetic fields (PEMFs) on healing of skin flaps. These investigations reported a decrease in the amount of necrosis of a skin flap after PEMF treatment. The skin flap model was chosen in these studies, as it is generally accepted for the investigation of the influence of different treatments on wound healing. The skin flap is a partially detached portion of the skin which retains part of its blood supply. However, if the flap is too long for its width, part of it will die after the transfer. Flap necrosis, therefore, represents a difficult clinical problem, especially in classes where a large area has to be covered. In the present study the authors address whether enhanced skin flap survival after treatment with PEMF is signal specific, that is , whether one could obtain similar results using various sinusoidal electromagnetic fields (SEMFs). Specifically, they investigated the influence on skin flap survival of SEMFs with different frequencies but the same maximum of dB/dt

  4. Tipping point leadership.

    Science.gov (United States)

    Kim, W Chan; Mauborgne, Renée

    2003-04-01

    When William Bratton was appointed police commissioner of New York City in 1994, turf wars over jurisdiction and funding were rife and crime was out of control. Yet in less than two years, and without an increase in his budget, Bratton turned New York into the safest large city in the nation. And the NYPD was only the latest of five law-enforcement agencies Bratton had turned around. In each case, he succeeded in record time despite limited resources, a demotivated staff, opposition from powerful vested interests, and an organization wedded to the status quo. Bratton's turnarounds demonstrate what the authors call tipping point leadership. The theory of tipping points hinges on the insight that in any organization, fundamental changes can occur quickly when the beliefs and energies of a critical mass of people create an epidemic movement toward an idea. Bratton begins by overcoming the cognitive hurdles that block organizations from recognizing the need for change. He does this by putting managers face-to-face with operational problems. Next, he manages around limitations on funds, staff, or equipment by concentrating resources on the areas that are most in need of change and that have the biggest payoffs. He meanwhile solves the motivation problem by singling out key influencers--people with disproportionate power due to their connections or persuasive abilities. Finally, he closes off resistance from powerful opponents. Not every CEO has the personality to be a Bill Bratton, but his successes are due to much more than his personality. He relies on a remarkably consistent method that any manager looking to turn around an organization can use to overcome the forces of inertia and reach the tipping point.

  5. Full-Band Quasi-Harmonic Analysis and Synthesis of Musical Instrument Sounds with Adaptive Sinusoids

    Directory of Open Access Journals (Sweden)

    Marcelo Caetano

    2016-05-01

    Full Text Available Sinusoids are widely used to represent the oscillatory modes of musical instrument sounds in both analysis and synthesis. However, musical instrument sounds feature transients and instrumental noise that are poorly modeled with quasi-stationary sinusoids, requiring spectral decomposition and further dedicated modeling. In this work, we propose a full-band representation that fits sinusoids across the entire spectrum. We use the extended adaptive Quasi-Harmonic Model (eaQHM to iteratively estimate amplitude- and frequency-modulated (AM–FM sinusoids able to capture challenging features such as sharp attacks, transients, and instrumental noise. We use the signal-to-reconstruction-error ratio (SRER as the objective measure for the analysis and synthesis of 89 musical instrument sounds from different instrumental families. We compare against quasi-stationary sinusoids and exponentially damped sinusoids. First, we show that the SRER increases with adaptation in eaQHM. Then, we show that full-band modeling with eaQHM captures partials at the higher frequency end of the spectrum that are neglected by spectral decomposition. Finally, we demonstrate that a frame size equal to three periods of the fundamental frequency results in the highest SRER with AM–FM sinusoids from eaQHM. A listening test confirmed that the musical instrument sounds resynthesized from full-band analysis with eaQHM are virtually perceptually indistinguishable from the original recordings.

  6. Computationally Efficient Amplitude Modulated Sinusoidal Audio Coding using Frequency-Domain Linear Prediction

    DEFF Research Database (Denmark)

    Christensen, M. G.; Jensen, Søren Holdt

    2006-01-01

    A method for amplitude modulated sinusoidal audio coding is presented that has low complexity and low delay. This is based on a subband processing system, where, in each subband, the signal is modeled as an amplitude modulated sum of sinusoids. The envelopes are estimated using frequency......-domain linear prediction and the prediction coefficients are quantized. As a proof of concept, we evaluate different configurations in a subjective listening test, and this shows that the proposed method offers significant improvements in sinusoidal coding. Furthermore, the properties of the frequency...

  7. High resolution DAS via sinusoidal frequency scan OFDR (SFS-OFDR).

    Science.gov (United States)

    Leviatan, Eyal; Eyal, Avishay

    2015-12-28

    There are many advantages to using direct frequency modulation for OFDR based DAS. However, achieving sufficiently linear scan via direct frequency modulation is challenging and poses limits on the scan parameters. A novel method for analyzing sinusoidal frequency modulated light is presented and demonstrated for both static and dynamic sensing. SFS-OFDR projects the measured signal onto appropriate sinusoidal phase terms to obtain spatial information. Thus, by using SFS-OFDR on sinusoidal modulated light it is possible to make use of the many advantages offered by direct frequency modulation without the limitations posed by the linearity requirement.

  8. AERODYNAMICS OF WING TIP SAILS

    Directory of Open Access Journals (Sweden)

    MUSHTAK AL-ATABI

    2006-06-01

    Full Text Available Observers have always been fascinated by soaring birds. An interesting feature of these birds is the existence of few feathers extending from the tip of the wing. In this paper, small lifting surfaces were fitted to the tip of a NACA0012 wing in a fashion similar to that of wing tip feathers. Experimental measurements of induced drag, longitudinal static stability and trailing vortex structure were obtained.The tests showed that adding wing tip surfaces (sails decreased the induced drag factor and increased the longitudinal static stability. Results identified two discrete appositely rotated tip vortices and showed the ability of wing tip surfaces to break them down and to diffuse them.

  9. Size-effects at a crack-tip interacting with a number of voids

    DEFF Research Database (Denmark)

    Tvergaard, Viggo; Niordson, Christian Frithiof

    2008-01-01

    A strain gradient plasticity theory is used to analyse the growth of discretely represented voids in front of a blunting crack tip, in order to study the influence of size effects on two competing mechanisms of crack growth. For a very small void volume fraction the crack tip tends to interact...

  10. AC losses in HTS coils for high-frequency and non-sinusoidal currents

    Science.gov (United States)

    de Bruyn, B. J. H.; Jansen, J. W.; Lomonova, E. A.

    2017-09-01

    AC losses in racetrack coils that are wound of YBCO tapes are measured for sinusoidal and non-sinusoidal transport currents with fundamental frequencies up to 1 kHz. An electrical method to measure losses for non-sinusoidal currents is developed for this purpose. The measured losses are compared to the losses calculated by 2D finite element models with power-law material models. The frequency and waveform-dependency of the measured losses are shown and compared to the results of the models over a wide range of frequencies and waveforms. Finally, it is shown that the finite element models can accurately predict AC losses resulting from non-sinusoidal transport currents as are present in highly dynamic motors with AC armature coils.

  11. Study of stability of a bandpass sigma delta modulator with sinusoidal input

    Energy Technology Data Exchange (ETDEWEB)

    Iu, Herbert H.C. [School of Electrical, Electronic and Computer Engineering, University of Western Australia, 35 Stirling Highway, Crawley (Australia)]. E-mail: herbert@ee.uwa.edu.au

    2007-07-15

    Bandpass sigma delta modulators (SDMs) have applications in areas such as digital radio demodulation. Stability issues of bandpass SDMs have been widely studied. Usually, zero or step inputs are considered. In this paper, we study the stability and non-linear phenomena of a bandpass SDM with sinusoidal input. In particular, the effects of the amplitude and frequency of the sinusoidal input signal will be investigated.

  12. An optimized method for mouse liver sinusoidal endothelial cell isolation

    Energy Technology Data Exchange (ETDEWEB)

    Meyer, Jeremy, E-mail: jeremy.meyer@hcuge.ch [Division of Digestive and Transplantation Surgery, University Hospitals of Geneva, Rue Gabrielle-Perret-Gentil 4, 1211 Genève 14 (Switzerland); Unit of Surgical Research, University of Geneva, Rue Michel-Servet 1, 1206 Genève (Switzerland); Lacotte, Stéphanie, E-mail: stephanie.lacotte@unige.ch [Unit of Surgical Research, University of Geneva, Rue Michel-Servet 1, 1206 Genève (Switzerland); Morel, Philippe, E-mail: philippe.morel@hcuge.ch [Division of Digestive and Transplantation Surgery, University Hospitals of Geneva, Rue Gabrielle-Perret-Gentil 4, 1211 Genève 14 (Switzerland); Unit of Surgical Research, University of Geneva, Rue Michel-Servet 1, 1206 Genève (Switzerland); Gonelle-Gispert, Carmen, E-mail: carmen.gonelle@unige.ch [Unit of Surgical Research, University of Geneva, Rue Michel-Servet 1, 1206 Genève (Switzerland); Bühler, Léo, E-mail: leo.buhler@hcuge.ch [Division of Digestive and Transplantation Surgery, University Hospitals of Geneva, Rue Gabrielle-Perret-Gentil 4, 1211 Genève 14 (Switzerland); Unit of Surgical Research, University of Geneva, Rue Michel-Servet 1, 1206 Genève (Switzerland)

    2016-12-10

    The objective of the present study was to develop an accurate and reproducible method for liver sinusoidal endothelial cell (LSEC) isolation in mice. Non-parenchymal cells were isolated using a modified two-step collagenase digestion combined with Optiprep density gradient centrifugation. LSEC were further purified using two prevalent methods, short-term selective adherence and CD146+ magnetic-activated cell sorting (MACS), and compared in terms of cell yield, viability and purity to our purification technique using CD11b cell depletion combined with long-term selective adherence. LSEC purification using our technique allowed to obtain 7.07±3.80 million LSEC per liver, while CD146+ MACS and short-term selective adherence yielded 2.94±1.28 and 0.99±0.66 million LSEC, respectively. Purity of the final cell preparation reached 95.10±2.58% when using our method. In contrast, CD146+ MACS and short-term selective adherence gave purities of 86.75±3.26% and 47.95±9.82%, respectively. Similarly, contamination by non-LSEC was the lowest when purification was performed using our technique, with a proportion of contaminating macrophages of only 1.87±0.77%. Further, isolated cells analysed by scanning electron microscopy presented typical LSEC fenestrations organized in sieve plates, demonstrating that the technique allowed to isolate bona fide LSEC. In conclusion, we described a reliable and reproducible technique for the isolation of high yields of pure LSEC in mice. This protocol provides an efficient method to prepare LSEC for studying their biological functions. - Highlights: • This protocol provides an efficient method to prepare primary mouse LSEC for studying their biological functions. • The liver cell dispersion step was improved by performing a retrograde cannulation of the liver. • The cell yield and the purity obtained were higher than comparative techniques in mice. • Contaminating macrophages were removed by introducing a CD11b- magnetic

  13. Tips for Divorcing Parents

    Science.gov (United States)

    [Skip to Content] for Parents Parents site Sitio para padres General Health Growth & Development Infections Diseases & Conditions Pregnancy & Baby Nutrition & Fitness Emotions & Behavior School & Family ...

  14. Crashworthiness Analysis and Evaluation of Fuselage Section with Sub-floor Composite Sinusoidal Specimens

    Directory of Open Access Journals (Sweden)

    H.L. Mou

    Full Text Available Abstract Crashworthiness is one of the main concerns in civil aviation safety particularly with regard to the increasing ratio of carbon fiber reinforced plastic (CFRP in aircraft primary structures. In order to generate dates for model validations, the mechanical properties of T700/3234 were obtained by material performance tests, and energy-absorbing results were gained by quasi-static crushing tests of composite sinusoidal specimens. The correctness of composite material model and single-layer finite element model of composite sinusoidal specimens were verified based on the simulation results and test results that were in good agreement. A typical civil aircraft fuselage section with composite sinusoidal specimens under cargo floor was suggested. The crashworthiness of finite element model of fuselage section was assessed by simulating the vertical drop test subjected to 7 m/s impact velocity, and the influences of different thickness of sub-floor composite sinusoidal specimens on crashworthiness of fuselage section were also analyzed. The simulation results show that the established finite element model can accurately simulate the crushing process of composite sinusoidal specimens; the failure process of fuselage section is more stable, and the safety of occupants can be effectively improved because of the smaller peak accelerations that was limited to human tolerance, a critical thickness of sub-floor composite sinusoidal specimens can restrict the magnitude of acceleration peaks, which has certain reference values for enhancing crashworthiness capabilities of fuselage section and improving the survivability of passengers.

  15. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

    Medline Plus

    Full Text Available ... liver disease are at greater risk for worsening liver failure after TIPS. If your liver failure is severe, a TIPS may not be the ... children are more likely to be performed before liver transplant in those with ascites or variceal ... 08, 2017 Send us your feedback Did you find the ...

  16. Crack Tip Flipping Under Mode I/III Tearing

    DEFF Research Database (Denmark)

    Felter, Christian Lotz; Specht Jensen, Lasse; Nielsen, Kim Lau

    Crack tip flipping, where the fracture surface alternates from side to side in 45° shear bands, seems to be an overlooked propagation mode in Mode I sheet tearing often disregarded as  “transitional” or tied to randomness in the material. In fact, such observations rarely make it to the literature....... However, crack tip flipping is a true propagation mode, but unlike those already established: i) it never settles in a steady-state as the near tip stress/strain field continuously change, and ii) the mechanism governing failure evolves behind the leading crack tip. Recent research has revealed new...... insight into this intriguing behavior of a crack propagating by the void nucleation and growth mechanism, and the work presented compiles both published and unpublished experimental and numerical findings. E.g. in a recent attempt to gain control of the flipping crack a slight Mode III was imposed...

  17. Tipping the scales.

    Science.gov (United States)

    1998-12-01

    In the US, the October 1998 murder of a physician who performed abortions was an outward manifestation of the insidious battle against legal abortion being waged by radical Christian social conservatives seeking to transform the US democracy into a theocracy. This movement has been documented in a publication entitled, "Tipping the Scales: The Christian Right's Legal Crusade Against Choice" produced as a result of a 4-year investigation conducted by The Center for Reproductive Law and Policy. This publication describes how these fundamentalists have used sophisticated legal, lobbying, and communication strategies to further their goals of challenging the separation of church and state, opposing family planning and sexuality education that is not based solely on abstinence, promoting school prayer, and restricting homosexual rights. The movement has resulted in the introduction of more than 300 anti-abortion bills in states, 50 of which have passed in 23 states. Most Christian fundamentalist groups provide free legal representation to abortion clinic terrorists, and some groups solicit women to bring specious malpractice claims against providers. Sophisticated legal tactics are used by these groups to remove the taint of extremism and mask the danger posed to US constitutional principles being posed by "a well-financed and zealous brand of radical lawyers and their supporters."

  18. Torsional Phacoemulsification and Tip Selection

    Directory of Open Access Journals (Sweden)

    Fırat Helvacıoğlu

    2014-10-01

    Full Text Available One of the recent advances in cataract surgery is torsional phacoemulsification. It was developed to increase the efficacy of ultrasonic emulsification. In torsional phacoemulsification, the torsional movement of the tip is translated to side-to-side cutting action with the aid of bent phaco tips. Lens material is cut in both directions, rather than only during a forward stroke. The efficiency of this technique is further enhanced by an improvement in followability provided by the inherent non-repulsive nature of the side-to-side motion. Tip selection is very important for the efficiency of torsional phacoemulsification. Theoretically, there are 2 ways to enhance the cutting efficiency of the tip. First is the stroke length; the 22-degree bent 30-degree Kelman mini-flared tip cuts longer than the 12-degree bent 30-degree mini-flared Kelman tip. Second is the angulation or bevel; the higher the degree (45 degrees, the better cutting efficiency. Retrospective analyses of the previously published clinical studies clearly demonstrated that the efficacy of the torsional phacoemulsification has positive correlation with both the aperture angles and neck angles of the tips. (Turk J Ophthalmol 2014; 44: 392-5

  19. Crack tip strain evolution and crack closure during overload of a growing fatigue crack

    Directory of Open Access Journals (Sweden)

    De-Qiang Wang

    2017-07-01

    Full Text Available It is generally accepted that fatigue crack growth is retarded after an overload, which has been explained either by plasticity-induced crack closure or near-tip residual stress. However, any interpretation of overload effect is insufficient if strain evolution in front of crack tip is not properly considered. The current understanding of overload-induced retardation lacks the clarification of the relationship between crack closure at crack wake and strain evolution at crack tip. In this work, a material with low work hardening coefficient was used to study the effect of overload on crack tip strain evolution and crack closure by in-situ SEM observation and digital image correlation technique. Crack opening displacement (COD and crack tip strain were measured before and after the overload. It was observed that the evolution of crack tip strain follows the crack opening behaviour behind the crack tip, indicating a smaller influence of overload on micro-mechanical behaviour of fatigue crack growth. After the overload, plastic strain accumulation was responsible for crack growth. The strain at a certain distance to crack tip was mapped, and it was found that the crack tip plastic zone size correlated well with crack growth rate during post-overload fatigue crack propagation.

  20. Electronically Tunable Quadrature Sinusoidal Oscillator with Equal Output Amplitudes during Frequency Tuning Process

    Directory of Open Access Journals (Sweden)

    Den Satipar

    2017-01-01

    Full Text Available A new configuration of voltage-mode quadrature sinusoidal oscillator is proposed. The proposed oscillator employs two voltage differencing current conveyors (VDCCs, two resistors, and two grounded capacitors. In this design, the use of multiple/dual output terminal active building block is not required. The tuning of frequency of oscillation (FO can be done electronically by adjusting the bias current of active device without affecting condition of oscillation (CO. The electronic tuning can be done by controlling the bias current using a digital circuit. The amplitude of two sinusoidal outputs is equal when the frequency of oscillation is tuned. This makes the sinusoidal output voltages meet good total harmonic distortions (THD. Moreover, the proposed circuit can provide the sinusoidal output current with high impedance which is connected to external load or to another circuit without the use of buffer device. To confirm that the oscillator can generate the quadrature sinusoidal output signal, the experimental results using VDCC constructed from commercially available ICs are also included. The experimental results agree well with theoretical anticipation.

  1. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

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    Full Text Available ... the TIPS. top of page Additional Information and Resources Society of Interventional Radiology (SIR) - Patient Center This ... To locate a medical imaging or radiation oncology provider in your community, you can search the ACR- ...

  2. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

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    Full Text Available ... Videos About Us News Physician Resources Professions Site Index A-Z Transjugular Intrahepatic Portosystemic Shunt (TIPS) Transjugular ... in the portal vein system. This pressure buildup can cause blood to flow backward from the liver ...

  3. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

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    Full Text Available ... pressure. top of page How does the procedure work? A TIPS reroutes blood flow in the liver ... physician will numb an area just above your right collarbone with a local anesthetic . A very small ...

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  8. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

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    Full Text Available ... the hepatic vein in the liver. A small metal device called a stent is placed to keep ... open by the placement of a small, tubular metal device commonly called a stent . During a TIPS ...

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  11. Choking and Strangulation Prevention Tips

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    ... Safety Sponsors Recalls Media Center Blog Videos Newsletter facebook twitter instagram pinterest gplus youtube Search Menu Why It Matters ... Safety Sponsors Recalls Media Center Blog Videos Newsletter facebook twitter instagram pinterest gplus youtube Sign up for quick tips ...

  12. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

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  3. Search Tips: MedlinePlus

    Science.gov (United States)

    ... of this page: https://medlineplus.gov/searchtips.html Search Tips To use the sharing features on this page, please enable JavaScript. How do I search MedlinePlus? The search box appears at the top ...

  4. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

    Medline Plus

    Full Text Available ... to the heart while avoiding the liver. TIPS may successfully reduce internal bleeding in the stomach and ... conditions, allergies and medications you’re taking. You may be advised to stop taking aspirin, nonsteroidal anti- ...

  5. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

    Medline Plus

    Full Text Available ... risks. Other possible complications of the procedure include: fever muscle stiffness in the neck bruising on the ... filtered out by the liver. The TIPS may cause too much of these substances to bypass the ...

  6. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

    Medline Plus

    Full Text Available ... avoiding the liver. TIPS may successfully reduce internal bleeding in the stomach and esophagus in patients with ... stomach, lower esophagus, and intestines, causing enlarged vessels, bleeding and the accumulation of fluid in the chest ...

  7. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

    Medline Plus

    Full Text Available ... system. This pressure buildup can cause blood to flow backward from the liver into the veins of ... does the procedure work? A TIPS reroutes blood flow in the liver and reduces abnormally high blood ...

  8. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

    Medline Plus

    Full Text Available ... liver back to the heart. top of page How should I prepare? You should report to your ... heart beat and blood pressure. top of page How does the procedure work? A TIPS reroutes blood ...

  9. Computerized automatic tip scanning operation

    International Nuclear Information System (INIS)

    Nishikawa, K.; Fukushima, T.; Nakai, H.; Yanagisawa, A.

    1984-01-01

    In BWR nuclear power stations the Traversing Incore Probe (TIP) system is one of the most important components in reactor monitoring and control. In previous TIP systems, however, operators have suffered from the complexity of operation and long operation time required. The system presented in this paper realizes the automatic operation of the TIP system by monitoring and driving it with a process computer. This system significantly reduces the burden on customer operators and improves plant efficiency by simplifying the operating procedure, augmenting the accuracy of the measured data, and shortening operating time. The process computer is one of the PODIA (Plant Operation by Displayed Information Automation) systems. This computer transfers control signals to the TIP control panel, which in turn drives equipment by microprocessor control. The process computer contains such components as the CRT/KB unit, the printer plotter, the hard copier, and the message typers required for efficient man-machine communications. Its operation and interface properties are described

  10. Tips to Prevent Tick Bites

    Science.gov (United States)

    Using the right insect repellent and other preventive actions can discourage ticks, mosquitoes, and other biting insects from landing on you. Tips include avoiding tick habitats and minimizing exposed skin.

  11. Tips to Prevent Mosquito Bites

    Science.gov (United States)

    Using the right insect repellent and other preventive actions can discourage mosquitoes from landing on you. Tips include removing mosquito habitats such as standing water, minimizing exposed skin, and staying indoors while mosquitoes are most active.

  12. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

    Medline Plus

    Full Text Available ... Patients who typically need a TIPS have portal hypertension , meaning they have increased pressure in the portal ... leading to cirrhosis (scarring of the liver). Portal hypertension can also occur in children, although children are ...

  13. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

    Medline Plus

    Full Text Available ... deeply you are sedated. When the needle is advanced through the liver and the pathway is expanded ... are the limitations of TIPS? Patients with more advanced liver disease are at greater risk for worsening ...

  14. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

    Medline Plus

    Full Text Available ... in creating the TIPS. top of page Additional Information and Resources Society of Interventional Radiology (SIR) - Patient ... Send us your feedback Did you find the information you were looking for? Yes No Please type ...

  15. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

    Medline Plus

    Full Text Available ... of page What are some common uses of the procedure? A TIPS is used to treat the ... during the procedure. top of page What does the equipment look like? In this procedure, x-ray ...

  16. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

    Medline Plus

    Full Text Available ... is completed. top of page What are the benefits vs. risks? Benefits A TIPS is designed to produce the same ... urgent intervention heart arrhythmias or congestive heart failure radiation injury to the skin is a rare complication ( ...

  17. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

    Medline Plus

    Full Text Available ... local anesthetic medications, general anesthesia or to contrast materials containing iodine (sometimes referred to as "dye" or " ... the placement of the TIPS stent, a contrast material will be injected in the hepatic vein to ...

  18. Tip model of cold fission

    International Nuclear Information System (INIS)

    Goennenwein, F.; Boersig, B.

    1991-01-01

    Cold fission is defined to be the limiting case of nuclear fission where virtually all of the available energy is converted into the total kinetic energy of the fragments. The fragments have, therefore, to be born in or at least close to their respective ground states. Starting from the viewpoint that cold fission corresponds to most compact scission configurations, energy constraints have been exploited to calculate minimum tip distances between the two nascent fragments in binary fission. Crucial input parameters to this tip model of cold fission are the ground-state deformations of fragment nuclei. It is shown that the minimum tip distances being compatible with energy conservation vary strongly with both the mass and charge fragmentation of the fission prone nucleus. The tip distances refer to nuclei with equivalent sharp surfaces. In keeping with the size of the surface width of leptodermous nuclei, only configurations where the tip distances are smaller than a few fm may be considered as valid scission configurations. From a comparison with experimental data on cold fission this critical tip distance appears to be 3.0 fm for the model parameters chosen. Whenever the model calculation yields tip distances being smaller than the critical value, a necessary condition for attaining cold fission is considered to be fulfilled. It is shown that this criterion allows to understand in fair agreement with experiment which mass fragmentations are susceptible to lead to cold fission and which fragment-charge divisions are the most favored in each isobaric mass chain. Being based merely on energy arguments, the model cannot aim at predicting fragment yields in cold fission. However, the tip model proposed appears well suited to delineate the phase space where cold fission phenomena may come into sight. (orig.)

  19. Conversion of Radio-Frequency Pulses to Continuous-Wave Sinusoids by Fast Switching and Narrowband Filtering

    Science.gov (United States)

    2016-09-01

    ARL-TN-0783 ● SEP 2016 US Army Research Laboratory Conversion of Radio -Frequency Pulses to Continuous- Wave Sinusoids by Fast...ARL-TN-0783 ● SEP 2016 US Army Research Laboratory Conversion of Radio -Frequency Pulses to Continuous- Wave Sinusoids by Fast...08/2016 4. TITLE AND SUBTITLE Conversion of Radio -Frequency Pulses to Continuous- Wave Sinusoids by Fast Switching and Narrowband Filtering 5a

  20. Light scattering by sinusoidal surfaces: illumination windows and harmonics in standards.

    Science.gov (United States)

    Marx, E; Lettieri, T R; Vorburger, T V

    1995-03-01

    Sinusoidal surfaces can be used as material standards to help calibrate instruments that measure the angular distribution of the intensity of light scattered by arbitrary surfaces, because the power in the diffraction peaks varies over several orders of magnitude. The calculated power in the higher-order diffraction peaks from sinusoidal surfaces expressed in terms of Bessel functions is much smaller than the values determined from angular distributions that are measured or computed from measured profiles, both of which are determined mainly by the harmonic contents of the profile. The finite size of the illuminated area, represented by an illumination window, gives rise to a background that is much larger than the calculated power in the higher-order peaks. For a rectangular window of a size equal to an even number of periods of the sinusoid, a computation of the power distribution produces minima at or near the location of the diffraction angles for higher-order diffraction angles.

  1. Effects of chopped sinusoidal voltages on the behavior and performance of laying hens

    Energy Technology Data Exchange (ETDEWEB)

    Vidali, G.; Silversides, F.G.; Boily, R. [Laval Univ., Quebec, PQ (Canada). Faculte de Sciences et Genie; Villeneuve, P.; Joncas, R. [Quebec Ministere de l`Agriculture, des Pecheries et de l`Aminentation, Ste-Foy, PQ (Canada)

    1996-04-01

    Studies were conducted to measure the effects of sinusoidal voltages on hens. One hundred and twenty laying hens between 23 and 43 weeks of age were used in these experiments. Normal sinusoidal voltages with constant amplitudes of one to nine volts and pulses with random amplitudes of 3 to 18 volts were applied to the hens. The electrical resistance of hens was also measured to determine their path resistance to electrical currents. No effects on production performance or behavior of laying hens were found. Neither water and feed consumption, nor egg production and quality were affected by the treatments. No behavioral or health problems were observed. 15 refs., 6 tabs., 2 figs.

  2. Rebreathing in the Mapleson A, C and D breathing systems with sinusoidal and exponential flow waveforms.

    Science.gov (United States)

    Cook, L B

    1997-12-01

    The degree of rebreathing in Mapleson A, C and D breathing systems for sinusoidal and exponential flow waveforms is analysed mathematically. The effects of altering the I:E ratio and of introducing an expiratory pause are investigated. The results for sinusoidal waveforms closely resemble those for a square wave. Exponential flow waveforms produce results similar to triangular flow waveforms. The Mapleson A system is always the most efficient. The Mapleson C system is efficient when the I:E ratio is 1:1, becoming less efficient with longer expiration and very inefficient with an expiratory pause. The Mapleson D system becomes efficient when the expiratory pause is long.

  3. Preventing Childhood Obesity: Tips for Parents and Caregivers

    Science.gov (United States)

    ... of weight gain while allowing normal growth and development. Don’t put your child on a weight-reduction diet without talking to ... regular physical activity prescription including social support The importance of continuing these lifestyle changes well past ... your Child's Weight at the Doctor Preventing Childhood Obesity: Tips ...

  4. Defoliation of strawberry mother plants for the production of runner tips

    Directory of Open Access Journals (Sweden)

    Miriane Dal Picio

    2014-07-01

    Full Text Available The objective of this work was to determine the sink-source relationships and their effects on the number and growth of runner tips of 'Camino Real' strawberry stock plants. Three types of sources were evaluated: one defoliation at 96 days after planting (DAP, two defoliations at 50 and 96 DAP, and mother plants without defoliation. Four types of sink were accessed: runner tips collected weekly and monthly, four stolons with rooted runner tips in pots, and four freely-grown stolons. A completely randomized experimental design was used in a split-plot arrangement, with four replicates. The source types were placed in the plots, and sink types in the subplots. The number of runner tips, the crown diameter, and the dry matter mass were determined. Number and growth of tips were higher on plants without defoliation, and decreased 44.7% on twice-defoliated mother plants. The two-defoliation management did not reduce runner tip dry matter mass only on plants with rooted stolons, which produced runner tips 50% heavier. Defoliation of mother plants bearing rooting stolons can be used to reduce their growth, without reducing the emission and growth of runner tips.

  5. Stability of sinusoidal responses of marginally stable bandpass sigma delta modulators

    OpenAIRE

    Ho, Charlotte Yuk-Fan; Ling, Bingo Wing-Kuen; Reiss, Joshua

    2006-01-01

    In this paper, we analyze the stability of the sinusoidal responses of second order interpolative marginally stable bandpass sigma delta modulators (SDMs) with the sum of the numerator and denominator polynomials equal to one and explore new results on the more general second order interpolative marginally stable bandpass SDMs. These results can be further extended to the high order interpolative marginally stable bandpass SDMs.

  6. Comparison between the water activation effects by pulsed and sinusoidal helium plasma jets

    Science.gov (United States)

    Xu, Han; Liu, Dingxin; Xia, Wenjie; Chen, Chen; Wang, Weitao; Liu, Zhijie; Wang, Xiaohua; Kong, Michael G.

    2018-01-01

    Comparisons between pulsed and sinusoidal plasma jets have been extensively reported for the discharge characteristics and gaseous reactive species, but rarely for the aqueous reactive species in water solutions treated by the two types of plasma jets. This motivates us to compare the concentrations of aqueous reactive species induced by a pulsed and a sinusoidal plasma jet, since it is widely reported that these aqueous reactive species play a crucial role in various plasma biomedical applications. Experimental results show that the aqueous H2O2, OH/O2-, and O2-/ONOO- induced by the pulsed plasma jet have higher concentrations, and the proportional difference increases with the discharge power. However, the emission intensities of OH(A) and O(3p5P) are higher for the sinusoidal plasma jet, which may be attributed to its higher gas temperature since more water vapor could participate in the plasma. In addition, the efficiency of bacterial inactivation induced by the pulsed plasma jet is higher than that for the sinusoidal plasma jet, in accordance with the concentration relation of aqueous reactive species for the two types of plasma jets.

  7. The hepatic sinusoid in aging and cirrhosis: effects on hepatic substrate disposition and drug clearance.

    Science.gov (United States)

    Le Couteur, David G; Fraser, Robin; Hilmer, Sarah; Rivory, Laurent P; McLean, Allan J

    2005-01-01

    The fenestrated sinusoidal endothelium ('liver sieve') and space of Disse in the healthy liver do not impede the transfer of most substrates, including drugs and oxygen, from the sinusoidal lumen to the hepatocyte. Plasma components transfer freely in both directions through the endothelial fenestrations and into the space of Disse. The endothelium is attenuated, there is no basement membrane and there is minimum collagen in the space of Disse, thus minimising any barriers to substrate diffusion. Both cirrhosis and aging are associated with marked structural changes in the sinusoidal endothelium and space of Disse that are likely to influence bulk plasma transfer into the space of Disse, and diffusion through the endothelium and space of Disse. These changes, termed capillarisation and pseudocapillarisation in cirrhosis and aging, respectively, impede the transfer of various substrates. Capillarisation is associated with exclusion of albumin, protein-bound drugs and macromolecules from the space of Disse, and the progressive transformation of flow-limited to barrier-limited distribution of some substrates. There is evidence that the sinusoidal changes in cirrhosis and aging contribute to hepatocyte hypoxia, thus providing a mechanism for the apparent differential reduction of oxygen-dependent phase I metabolic pathways in these conditions. Structural change and subsequent dysfunction of the liver sieve warrant consideration as a significant factor in the impairment of overall substrate handling and hepatic drug metabolism in cirrhosis and aging.

  8. A Perceptual Model for Sinusoidal Audio Coding Based on Spectral Integration

    NARCIS (Netherlands)

    Van de Par, S.; Kohlrausch, A.; Heusdens, R.; Jensen, J.; Holdt Jensen, S.

    2005-01-01

    Psychoacoustical models have been used extensively within audio coding applications over the past decades. Recently, parametric coding techniques have been applied to general audio and this has created the need for a psychoacoustical model that is specifically suited for sinusoidal modelling of

  9. A Perceptual Model for Sinusoidal Audio Coding Based on Spectral Integration

    Directory of Open Access Journals (Sweden)

    Jensen Søren Holdt

    2005-01-01

    Full Text Available Psychoacoustical models have been used extensively within audio coding applications over the past decades. Recently, parametric coding techniques have been applied to general audio and this has created the need for a psychoacoustical model that is specifically suited for sinusoidal modelling of audio signals. In this paper, we present a new perceptual model that predicts masked thresholds for sinusoidal distortions. The model relies on signal detection theory and incorporates more recent insights about spectral and temporal integration in auditory masking. As a consequence, the model is able to predict the distortion detectability. In fact, the distortion detectability defines a (perceptually relevant norm on the underlying signal space which is beneficial for optimisation algorithms such as rate-distortion optimisation or linear predictive coding. We evaluate the merits of the model by combining it with a sinusoidal extraction method and compare the results with those obtained with the ISO MPEG-1 Layer I-II recommended model. Listening tests show a clear preference for the new model. More specifically, the model presented here leads to a reduction of more than 20% in terms of number of sinusoids needed to represent signals at a given quality level.

  10. A perceptual model for sinusoidal audio coding based on spectral integration

    NARCIS (Netherlands)

    Van de Par, S.; Kohlrauch, A.; Heusdens, R.; Jensen, J.; Jensen, S.H.

    2005-01-01

    Psychoacoustical models have been used extensively within audio coding applications over the past decades. Recently, parametric coding techniques have been applied to general audio and this has created the need for a psychoacoustical model that is specifically suited for sinusoidal modelling of

  11. Measurement of definite integral of sinusoidal signal absolute value third power using digital stochastic method

    Directory of Open Access Journals (Sweden)

    Beljić Željko

    2017-01-01

    Full Text Available In this paper a special case of digital stochastic measurement of the third power of definite integral of sinusoidal signal’s absolute value, using 2-bit AD converters is presented. This case of digital stochastic method had emerged from the need to measure power and energy of the wind. Power and energy are proportional to the third power of wind speed. Anemometer output signal is sinusoidal. Therefore an integral of the third power of sinusoidal signal is zero. Two approaches are proposed for the third power calculation of the wind speed signal. One approach is to use absolute value of sinusoidal signal (before AD conversion for which there is no need of multiplier hardware change. The second approach requires small multiplier hardware change, but input signal remains unchanged. For the second approach proposed minimal hardware change was made to calculate absolute value of the result after AD conversion. Simulations have confirmed theoretical analysis. Expected precision of wind energy measurement of proposed device is better than 0,00051% of full scale. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. TR32019

  12. Liver sinusoidal endothelial cells induce immunosuppressive IL-10-producing Th1 cells via the Notch pathway

    NARCIS (Netherlands)

    Neumann, Katrin; Rudolph, Christine; Neumann, Christian; Janke, Marko; Amsen, Derk; Scheffold, Alexander

    2015-01-01

    Under homeostasis, liver sinusoidal endothelial cells (LSECs) shift intrahepatic T-cell responses towards tolerance. However, the role of LSECs in the regulation of T-cell-induced liver inflammation is less clear. Here, we studied the capacity of LSECs to modulate pro-inflammatory Th1-cell

  13. Stress singularities in a model of a wood disk under sinusoidal pressure

    Science.gov (United States)

    Jay A. Johnson; John C. Hermanson; Steven M. Cramer; Charles Amundson

    2005-01-01

    A thin, solid, circular wood disk, cut from the transverse plane of a tree stem, can be modeled as a cylindrically orthotropic elastic material. It is known that a stress singularity can occur at the center of a cylindrically orthotropic disk subjected to uniform pressure. If a solid cylindrically orthotropic disk is subjected to sinusoidal pressure distributions, then...

  14. Nanobits: customizable scanning probe tips

    DEFF Research Database (Denmark)

    Kumar, Rajendra; Shaik, Hassan Uddin; Sardan Sukas, Özlem

    2009-01-01

    We present here a proof-of-principle study of scanning probe tips defined by planar nanolithography and integrated with AFM probes using nanomanipulation. The so-called 'nanobits' are 2-4 mu m long and 120-150 nm thin flakes of Si3N4 or SiO2, fabricated by electron beam lithography and standard...... or dislocation of the tips of the nanobit after several scans. This approach allows an unprecedented freedom in adapting the shape and size of scanning probe tips to the surface topology or to the specific application....... silicon processing. Using a microgripper they were detached from an array and fixed to a standard pyramidal AFM probe or alternatively inserted into a tipless cantilever equipped with a narrow slit. The nanobit-enhanced probes were used for imaging of deep trenches, without visible deformation, wear...

  15. Effects of irradiation on physicochemical and sensory qualities of fermented shoot tip of sweet potato

    International Nuclear Information System (INIS)

    Cui Li; Liu Chunquan; Li Dajing; Song Jiangfeng; Jiang Ning; Liu Chunju; Wu Haihong; Zhu Danyu

    2011-01-01

    The effect of irradiation on sensory quality, physicochemical and functional prosperities of fermented shoot tips of sweet potatoes were studied. The results showed that total content of free amino acids in fermented shoot tips of sweet potato were not influenced at 4 kGy irradiation, but increased at 6 kGy. Total content of organic acids in shoot tips were not influenced by 2 ∼ 6 kGy of irradiation. The total viable cells of the tips was reduced from 7.35 to 4.67 log CFU/g at 2 kGy irradiation, and no growth of total viable cells was observed at 4 and 6 kGy irradiated fermented shoot tips. It is recommended that 4 kGy was the endurance irradiation dose for fermented shoot tips of sweet potato to ensure the maximum retention of taste quality and health-relevant functionality. (authors)

  16. Defining tipping points for social-ecological systems scholarship—an interdisciplinary literature review

    Science.gov (United States)

    Milkoreit, Manjana; Hodbod, Jennifer; Baggio, Jacopo; Benessaiah, Karina; Calderón-Contreras, Rafael; Donges, Jonathan F.; Mathias, Jean-Denis; Rocha, Juan Carlos; Schoon, Michael; Werners, Saskia E.

    2018-03-01

    The term tipping point has experienced explosive popularity across multiple disciplines over the last decade. Research on social-ecological systems (SES) has contributed to the growth and diversity of the term’s use. The diverse uses of the term obscure potential differences between tipping behavior in natural and social systems, and issues of causality across natural and social system components in SES. This paper aims to create the foundation for a discussion within the SES research community about the appropriate use of the term tipping point, especially the relatively novel term ‘social tipping point.’ We review existing literature on tipping points and similar concepts (e.g. regime shifts, critical transitions) across all spheres of science published between 1960 and 2016 with a special focus on a recent and still small body of work on social tipping points. We combine quantitative and qualitative analyses in a bibliometric approach, rooted in an expert elicitation process. We find that the term tipping point became popular after the year 2000—long after the terms regime shift and critical transition—across all spheres of science. We identify 23 distinct features of tipping point definitions and their prevalence across disciplines, but find no clear taxonomy of discipline-specific definitions. Building on the most frequently used features, we propose definitions for tipping points in general and social tipping points in SES in particular.

  17. Influence of residual stresses and loading frequencies on corrosion fatigue crack growth behavior of weldments

    Science.gov (United States)

    Kitsunai, Y.; Tanaka, M.; Yoshihisa, E.

    1998-04-01

    The effect of residual stresses and loading frequencies on corrosion fatigue crack growth behavior under synthetic seawater with a free corrosion potential was examined using center-cracked tension (CCT) and single edge-cracked tension (SECT) specimens machined from mild steel butt-welded joints and the parent material. A series of fatigue crack growth tests were carried out with a sinusoidal loading wave form at a stress ratio of 0.05 with a loading frequency of 0.017 to 6.7 Hz. The results show that the crack growth resistance of a weld metal in the SECT specimen is higher than that in the CCT specimen regardless of testing conditions. The discrepancy is attributed to the differences in residual stress distribution at the crack tip in the two specimen geometries. The crack growth rate of the weld metal in the CCT specimen in seawater increased with decreasing loading frequency. The acceleration of the crack growth rate may be related to the occurrence of brittle striation or cleavage due to hydrogen embrittlement. It was found that the corrosion fatigue crack growth rate of a welded joint with tensile residual stress can be predicted using the effective stress intensity factor range, which takes into account both the residual stress and the loading frequency effects.

  18. Tip-over stability of spent fuel storage cask subjected to seismic load

    International Nuclear Information System (INIS)

    Shirai, Koji; Ito, Chihiro; Saegusa, Toshiari; Ryu, Hiroshi.

    1994-01-01

    Cask storage method is the most preferable to store spent fuel at a reactor site. Since the cask is vertically oriented within the storage facility, it is necessary to investigate the tipping-over stability of the cask subjected to seismic load. In this paper, an evaluation method of the seismic response of the cask subjected to earthquake motions is proposed. Firstly, shaking table tests were conducted using a scaled cask model on a reinforced concrete base, considering a similarity law. According to these test results, the characteristics of the tipping-over response of the cask under sinusoidal waves and natural earthquake waves were investigated, and the tipping-over stability of the cask subjected to seismic load was confirmed. Secondly, based on the assumption that the tipping-over behavior could be treated as a two-dimensional problem, the numerical simulations were carried out by means of distinct element method and compared with the experimental results. As a result, the applicability of this code for seismic response of the cask was made clear. (author)

  19. ZBrush Professional Tips and Techniques

    CERN Document Server

    Gaboury, Paul

    2012-01-01

    Learn to work effectively and creatively with all versions of ZBrush! ZBrush is used by top artists in Hollywood to model and sculpt characters in such films as Avatar, Iron Man, and Pirates of the Caribbean. In addition, this amazing technology is also used in jewelry design, forensic science, aerospace, video games, toy creation, and the medical field. Written by Pixologic's in-house ZBrush expert Paul Gaboury, this full-color, beautifully illustrated guide provides you with the ultimate tips and tricks to maximize your use of all versions of ZBrush. Reveals numerous little-known tips and tr

  20. Office 2010 Visual Quick Tips

    CERN Document Server

    Gunter, Sherry Kinkoph

    2010-01-01

    Get more done in Office 2010 in less time with these Quick Tips!. Whether you're new to Microsoft Office or updating from older versions, this is the perfect resource to get you quickly up to speed on Office 2010. Every application is covered, including Word, Excel, PowerPoint, Outlook, and Publisher. Full-color screenshots and numbered steps clearly explain dozens of features and functions-while quick shortcuts, tips, and tricks help you save time and boost productivity. You'll also find great new ways to access and use some Office apps right from the Web.: Walks you through dozens of new fea

  1. Dynamic Strain Evolution around a Crack Tip under Steady- and Overloaded-Fatigue Conditions

    Directory of Open Access Journals (Sweden)

    Soo Yeol Lee

    2015-11-01

    Full Text Available We investigated the evolution of the strain fields around a fatigued crack tip between the steady- and overloaded-fatigue conditions using a nondestructive neutron diffraction technique. The two fatigued compact-tension specimens, with a different fatigue history but an identical applied stress intensity factor range, were used for the direct comparison of the crack tip stress/strain distributions during in situ loading. While strains behind the crack tip in the steady-fatigued specimen are irrelevant to increasing applied load, the strains behind the crack tip in the overloaded-fatigued specimen evolve significantly under loading, leading to a lower driving force of fatigue crack growth. The results reveal the overload retardation mechanism and the correlation between crack tip stress distribution and fatigue crack growth rate.

  2. Numerical Prediction of Tip Vortex Cavitation for Marine Propellers in Non-uniform Wake

    Science.gov (United States)

    Zhu, Zhi-Feng; Zhou, Fang; Li, Dan

    2017-07-01

    Tip vortex cavitation is the first type of cavitation to take place around most marine propellers. But the numerical prediction of tip vortex cavitation is one of the challenges for propeller wake because of turbulence dissipation during the numerical simulation. Several parameters of computational mesh and numerical algorithm are tested by mean of the predicted length of tip vortex cavtiation to validate a developed method. The predicted length of tip vortex cavtiation is on the increase about 0.4 propeller diameters using the developed numerical method. The predicted length of tip vortex cavtiation by RNG k - ɛ model is about 3 times of that by SST k - ω model. Therefore, based on the validation of the present approach, the cavitating flows generated by two rotating propellers under a non-uniform inflow are calculated further. The distributions of axial velocity, total pressure and vapor volume fraction in the transversal planes across tip vortex region are shown to be useful in analyzing the feature of the cavitating flow. The strongest kernel of tip vortex cavitation is not at the position most close to blade tip but slightly far away from the region. During the growth of tip vortex cavitation extension, it appears short and thick, and then it becomes long and thin. The pressure fluctuations at the positions inside tip vortex region also validates the conclusion. A key finding of the study is that the grids constructed especially for tip vortex flows by using separated computational domain is capable of decreasing the turbulence dissipation and correctly capturing the feature of propeller tip vortex cavitation under uniform and non-uniform inflows. The turbulence model and advanced grids is important to predict tip vortex cavitation.

  3. Effect of crack propagation on crack tip fields

    Directory of Open Access Journals (Sweden)

    F.V. Antunes

    2013-07-01

    Full Text Available Crack closure influences fatigue crack growth rate and must be included in the design of components. Plasticity induced crack closure is intimately linked with the crack tip plastic deformation, which becomes residual as the crack propagates. The objective here is to study numerically the effect of crack propagation on crack tip fields. The transient effect observed at the beginning of crack propagation is linked to the hardening behavior of material. The effect of mesh refinement is studied, and a singular behavior is evident, which is explained by the sharp crack associated with mesh topology, composed of a regular pattern of square elements. The plastic zone size measured perpendicularly to crack flank in the residual plastic wake is quantified and compared with literature models. Finally, the removal of material at the first node behind crack tip with load cycling was observed for plane strain state and some hardening models in plane stress state.

  4. The tip of the iceberg

    DEFF Research Database (Denmark)

    Bjørst, Lill Rastad

    2010-01-01

      Abstract: The tip of the iceberg: Ice as a nonhuman actor of the climate change debate   The global climate change debate has the Arctic as a core region of concern and ice has become a central aspect of discourses. This article discusses ice representations from six different contexts linked...

  5. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

    Medline Plus

    Full Text Available ... in creating the TIPS. top of page Additional Information and Resources Society of Interventional Radiology (SIR) - Patient Center This page ... of Use | Links | Site Map Copyright © 2018 ... To help ensure current and accurate information, we do not permit copying but encourage linking ...

  6. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

    Medline Plus

    Full Text Available ... pressure. top of page How does the procedure work? A TIPS reroutes blood flow in the liver and reduces abnormally high blood pressure in the veins of the stomach, esophagus, bowel and liver, reducing the risk of bleeding from enlarged veins across the esophagus ...

  7. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

    Medline Plus

    Full Text Available ... failure is severe, a TIPS may not be the best use and a different procedure may be needed to control your symptoms. They are also at risk for encephalopathy , which is an alteration of normal brain function that can lead to confusion. This is ...

  8. Food Allergy: Tips to Remember

    Science.gov (United States)

    ... or get better on their own. Outgrowing Food Allergies Most children outgrow their allergies to cow’s milk, egg, soy ... can help you learn when you or your child’s food allergies are resolving with time. Healthy Tips • Always ask ...

  9. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

    Medline Plus

    Full Text Available Toggle navigation Test/Treatment Patient Type Screening/Wellness Disease/Condition Safety En Español More Info Images/Videos ... limitations of TIPS? Patients with more advanced liver disease are at greater risk for worsening liver failure ...

  10. Assigning Effective Homework. Classroom Tips

    Science.gov (United States)

    American Federation of Teachers (NJ), 2010

    2010-01-01

    Each new school year brings high hopes, great expectations and challenges for both new and seasoned educators. The American Federation of Teachers (AFT) has developed a series called "Classroom Tips" to help educators start the year right and anticipate the year ahead. Over the past 40 years, most research studies on homework have found that…

  11. Predicting casualties implied by TIPs

    Science.gov (United States)

    Trendafiloski, G.; Wyss, M.; Wyss, B. M.

    2009-12-01

    When an earthquake is predicted, forecast, or expected with a higher than normal probability, losses are implied. We estimated the casualties (fatalities plus injured) that should be expected if earthquakes in TIPs (locations of Temporarily Increased Probability of earthquakes) defined by Kossobokov et al. (2009) should occur. We classified the predictions of losses into the categories red (more than 400 fatalities or more than 1,000 injured), yellow (between 100 and 400 fatalities), green (fewer than 100 fatalities), and gray (undetermined). TIPs in Central Chile, the Philippines, Papua, and Taiwan are in the red class, TIPs in Southern Sumatra, Nicaragua, Vanatu, and Honshu in the yellow class, and TIPs in Tonga, Loyalty Islands, Vanatu, S. Sandwich Islands, Banda Sea, and the Kuriles, are classified as green. TIPs where the losses depend moderately on the assumed point of major energy release were classified as yellow; TIPs such as in the Talaud Islands and in Tonga, where the losses depend very strongly on the location of the epicenter, were classified as gray. The accuracy of loss estimates after earthquakes with known hypocenter and magnitude are affected by uncertainties in transmission and soil properties, the composition of the building stock, the population present, and the method by which the numbers of casualties are calculated. In the case of TIPs, uncertainties in magnitude and location are added, thus we calculate losses for a range of these two parameters. Therefore, our calculations can only be considered order of magnitude estimates. Nevertheless, our predictions can come to within a factor of two of the observed numbers, as in the case of the M7.6 earthquake of October 2005 in Pakistan that resulted in 85,000 fatalities (Wyss, 2005). In subduction zones, the geometrical relationship between the earthquake source capable of a great earthquake and the population is clear because there is only one major fault plane available, thus the epicentral

  12. Effect of material damage on the stress-strain state near a crack tip in creep

    Science.gov (United States)

    Astaf'ev, V. I.; Grigorova, T. V.; Pastukhov, V. A.

    1992-02-01

    The asymptotic stress and damage fields near the tip of a growing crack are determined for a creep-damaged material described by Rabotnov-Hayhurst-Leckie constitutive equations. It is found that the singular stress field, characteristic of the crack theory, is absent near the crack tip, which is consistent with the results of finite element solutions for tearing cracks. A crack growth law is obtained which provides a qualitative description of the crack growth process in stainless steels under constant loading.

  13. Mini-flared Kelman tip, reverse tip, and sidewinder tip with torsional phaco: a prospective randomized comparative study

    Directory of Open Access Journals (Sweden)

    Wilson Takashi Hida

    2015-02-01

    Full Text Available Purpose: To compare the efficiency of surgical procedures using three phaco tip designs in torsional phacoemulsification using the bevel-down technique. Methods: In this prospective, comparative, masked study, patients were randomly assigned to have torsional coaxial microincision cataract surgery using the mini-flared 45-degree Kelman tip, reversed mini-flared 30-degree Kelman tip, or Sidewinder 30-degree Kelman tip. Clinical measurements included preoperative and 3-month postoperative corrected distance visual acuity (CDVA, endothelial cell counts (ECC, and preoperative and 1-day postoperative central corneal thickness (CCT. Intraoperative measurements included phaco time, torsional time, aspiration time, case time, cumulative dissipated energy (CDE, and balanced salt solution volume (BSS. Results: The study evaluated 150 eyes of 150 patients. Intraoperatively, there was no statistically significant difference in cumulative dissipated energy, case time, torsional time, and aspiration time between the three tip configurations. However, less phaco time was used with the mini-flared 45-degree Kelman tip (p=0.02 than that with the Sidewinder 30-degree Kelman tip or reversed mini-flared 30-degree Kelman tip. The mini-flared 45-degree Kelman tip and the reversed mini-flared 30-degree Kelman tip required significantly less balanced salt solution volume than that required by the Sidewinder 30-degree Kelman tip (p=0.009. There was no statistically significant difference in corrected distance visual acuity and endothelial cell counts between tips 3 months postoperatively (p>0.05. Conclusion: All three tips were effective with no intraoperative complications. When using torsional phacoemulsification through microincisions and the prefracture technique with the bevel-down technique, the mini-flared 45-degree Kelman tip required a lower mean phaco time than the reversed mini-flared 30-degree Kelman tip and the Sidewinder 30-degree Kelman tip.

  14. Direct Fabrication of Carbon Nanotubes STM Tips by Liquid Catalyst-Assisted Microwave Plasma-Enhanced Chemical Vapor Deposition

    Directory of Open Access Journals (Sweden)

    Fa-Kuei Tung

    2009-01-01

    Full Text Available Direct and facile method to make carbon nanotube (CNT tips for scanning tunneling microscopy (STM is presented. Cobalt (Co particles, as catalysts, are electrochemically deposited on the apex of tungsten (W STM tip for CNT growth. It is found that the quantity of Co particles is well controlled by applied DC voltage, concentration of catalyst solution, and deposition time. Using optimum growth condition, CNTs are successfully synthesized on the tip apex by catalyst-assisted microwave-enhanced chemical vapor deposition (CA-MPECVD. A HOPG surface is clearly observed at an atomic scale using the present CNT-STM tip.

  15. Parenting Tips: How to Improve Toddler Behavior

    Science.gov (United States)

    ... issues. To encourage listening and cooperation, follow these parenting tips. By Mayo Clinic Staff Life can be ... and a degree of routine. Consider these practical parenting tips. Make sure your displays of affection for ...

  16. Tips for Good Oral Health during Pregnancy

    Science.gov (United States)

    Tips for Good Oral Health During Pregnancy B elow are tips for taking care of your oral health while you are pregnant. Getting oral health care, practicing good oral hygiene, eating healthy foods, ...

  17. School Avoidance: Tips for Concerned Parents

    Science.gov (United States)

    ... Email Print Share School Avoidance: Tips for Concerned Parents Page Content ​School avoidance – sometimes called school refusal ... school bully) Actual physical harm Tips for Concerned Parents: As a first step, the management of school ...

  18. Radiofrequency Wire Recanalization of Chronically Thrombosed TIPS

    Energy Technology Data Exchange (ETDEWEB)

    Majdalany, Bill S., E-mail: bmajdala@med.umich.edu [University of Michigan Health System, Division of Interventional Radiology, Department of Radiology (United States); Elliott, Eric D., E-mail: eric.elliott@osumc.edu [The Ohio State University Wexner Medical Center, Division of Interventional Radiology, Department of Radiology (United States); Michaels, Anthony J., E-mail: Anthony.michaels@osumc.edu; Hanje, A. James, E-mail: James.Hanje@osumc.edu [The Ohio State University Wexner Medical Center, Division of Gastroenterology and Hepatology, Department of Medicine (United States); Saad, Wael E. A., E-mail: wsaad@med.umich.edu [University of Michigan Health System, Division of Interventional Radiology, Department of Radiology (United States)

    2016-07-15

    Radiofrequency (RF) guide wires have been applied to cardiac interventions, recanalization of central venous thromboses, and to cross biliary occlusions. Herein, the use of a RF wire technique to revise chronically occluded transjugular intrahepatic portosystemic shunts (TIPS) is described. In both cases, conventional TIPS revision techniques failed to revise the chronically thrombosed TIPS. RF wire recanalization was successfully performed through each of the chronically thrombosed TIPS, demonstrating initial safety and feasibility in this application.

  19. Fracture mechanics by three-dimensional crack-tip synchrotron X-ray microscopy.

    Science.gov (United States)

    Withers, P J

    2015-03-06

    To better understand the relationship between the nucleation and growth of defects and the local stresses and phase changes that cause them, we need both imaging and stress mapping. Here, we explore how this can be achieved by bringing together synchrotron X-ray diffraction and tomographic imaging. Conventionally, these are undertaken on separate synchrotron beamlines; however, instruments capable of both imaging and diffraction are beginning to emerge, such as ID15 at the European Synchrotron Radiation Facility and JEEP at the Diamond Light Source. This review explores the concept of three-dimensional crack-tip X-ray microscopy, bringing them together to probe the crack-tip behaviour under realistic environmental and loading conditions and to extract quantitative fracture mechanics information about the local crack-tip environment. X-ray diffraction provides information about the crack-tip stress field, phase transformations, plastic zone and crack-face tractions and forces. Time-lapse CT, besides providing information about the three-dimensional nature of the crack and its local growth rate, can also provide information as to the activation of extrinsic toughening mechanisms such as crack deflection, crack-tip zone shielding, crack bridging and crack closure. It is shown how crack-tip microscopy allows a quantitative measure of the crack-tip driving force via the stress intensity factor or the crack-tip opening displacement. Finally, further opportunities for synchrotron X-ray microscopy are explored.

  20. Injector tip for an internal combustion engine

    Science.gov (United States)

    Shyu, Tsu Pin; Ye, Wen

    2003-05-20

    This invention relates to a the tip structure of a fuel injector as used in a internal combustion engine. Internal combustion engines using Homogeneous Charge Compression Ignition (HCCI) technology require a tip structure that directs fuel spray in a downward direction. This requirement necessitates a tip design that is capable of withstanding mechanical stresses associated with the design.

  1. The two dynamical states in sinusoidal potentials: An analog simulation experiment

    Science.gov (United States)

    Sawkmie, Ivan Skhem; Mahato, Mangal C.

    2018-04-01

    The phenomenon of stochastic resonance (SR) is usually found to occur theoretically as well as experimentally in bi-stable systems [1]. Recently, it was numerically shown that SR is found to occur in underdamped (friction coefficient γ) sinusoidal potentials also. The occurrence of SR is explained in terms of two competing dynamical states of trajectories as a response to the external periodic drive. We setup an analog simulation experiment similar to the analog simulation work done earlier to study stochastic nonlinear dynamics [2], to verify the existence of the two dynamical states and to investigate the occurrence of SR in sinusoidal potentials obtained earlier [3]. We discuss our experimental setup and the results obtained in detail.

  2. Human thermal sensation: frequency response to sinusoidal stimuli at the surface of the skin

    DEFF Research Database (Denmark)

    Ring, J.W.; de Dear, Richard; Melikov, Arsen Krikor

    1993-01-01

    . A psychosensory intensity (PSI) model has been developed to relate experimentally derived sensation data to simulated cutaneous thermoreceptor responses to the temperature ramp-plateaux and step stimuli applied to the skin surface by thermodes. From the point of view of signal processing, a natural extension...... of this approach is to ask what the response would be to sinusoidally varying stimuli of differing frequencies, or, in other words, what would be the frequency response of this skin system? The purpose of this paper is to extend the PSI model and apply these sinusoids to it and hence find the frequency response...... function. This function is then compared with the functional form found in two experiments where the stimuli were pulsating airflows of differing frequency. The PSI model seems to simulate well the form of the response of the human skin system to varying temperature changes of a whole range of frequencies...

  3. Credibility Test for Frequency Estimation of Sinusoid Using Chebyshev’s Inequality

    Directory of Open Access Journals (Sweden)

    Hu Guobing

    2014-01-01

    Full Text Available Estimation of sinusoid frequency is a key research problem related to radar, sonar, and communication systems. The results of numerous investigations on frequency estimation have been reported in the literature. Nevertheless, to the best of our knowledge, none of them have dealt with credibility evaluation, which is used to decide whether an individual frequency estimate of the sinusoid is accurate or not. In this study, the credibility problem is modeled as a hypothesis test based on Chebyshev’s inequality (CI. The correlation calculated from the received signal and the reference signal generated according to the frequency estimate is used as a test statistic. A threshold is determined based on CI, and the analytical expression for the frequency estimation credibility detection performance is derived. Simulations show that the proposed method performs well even at low signal-to-noise ratios.

  4. Rapid and efficient clearance of blood-borne virus by liver sinusoidal endothelium.

    Directory of Open Access Journals (Sweden)

    Latha P Ganesan

    2011-09-01

    Full Text Available The liver removes quickly the great bulk of virus circulating in blood, leaving only a small fraction to infect the host, in a manner characteristic of each virus. The scavenger cells of the liver sinusoids are implicated, but the mechanism is entirely unknown. Here we show, borrowing a mouse model of adenovirus clearance, that nearly all infused adenovirus is cleared by the liver sinusoidal endothelial cell (LSEC. Using refined immunofluorescence microscopy techniques for distinguishing macrophages and endothelial cells in fixed liver, and identifying virus by two distinct physicochemical methods, we localized adenovirus 1 minute after infusion mainly to the LSEC (∼90%, finding ∼10% with Kupffer cells (KC and none with hepatocytes. Electron microscopy confirmed our results. In contrast with much prior work claiming the main scavenger to be the KC, our results locate the clearance mechanism to the LSEC and identify this cell as a key site of antiviral activity.

  5. Multilevel-Dc-Bus Inverter For Providing Sinusoidal And Pwm Electrical Machine Voltages

    Science.gov (United States)

    Su, Gui-Jia [Knoxville, TN

    2005-11-29

    A circuit for controlling an ac machine comprises a full bridge network of commutation switches which are connected to supply current for a corresponding voltage phase to the stator windings, a plurality of diodes, each in parallel connection to a respective one of the commutation switches, a plurality of dc source connections providing a multi-level dc bus for the full bridge network of commutation switches to produce sinusoidal voltages or PWM signals, and a controller connected for control of said dc source connections and said full bridge network of commutation switches to output substantially sinusoidal voltages to the stator windings. With the invention, the number of semiconductor switches is reduced to m+3 for a multi-level dc bus having m levels. A method of machine control is also disclosed.

  6. Analysis and Implementation of Multiple Bionic Motion Patterns for Caterpillar Robot Driven by Sinusoidal Oscillator

    OpenAIRE

    Yanhe Zhu; Xiaolu Wang; Jizhuang Fan; Sajid Iqbal; Dongyang Bie; Jie Zhao

    2014-01-01

    Articulated caterpillar robot has various locomotion patterns—which make it adaptable to different tasks. Generally, the researchers have realized undulatory (transverse wave) and simple rolling locomotion. But many motion patterns are still unexplored. In this paper, peristaltic locomotion and various additional rolling patterns are achieved by employing sinusoidal oscillator with fixed phase difference as the joint controller. The usefulness of the proposed method is verified using simulati...

  7. Identification of moving sinusoidal wave loads for sensor structural configuration by finite element inverse method

    Science.gov (United States)

    Zhang, B.; Yu, S.

    2018-03-01

    In this paper, a beam structure of composite materials with elastic foundation supports is established as the sensor model, which propagates moving sinusoidal wave loads. The inverse Finite Element Method (iFEM) is applied for reconstructing moving wave loads which are compared with true wave loads. The conclusion shows that iFEM is accurate and robust in the determination of wave propagation. This helps to seek a suitable new wave sensor method.

  8. A Novel Modular Bioreactor to In Vitro Study the Hepatic Sinusoid

    OpenAIRE

    Illa, Xavi; Vila, Sergi; Yeste, Jose; Peralta, Carmen; Gracia-Sancho, Jordi; Villa, Rosa

    2014-01-01

    We describe a unique, versatile bioreactor consisting of two plates and a modified commercial porous membrane suitable for in vitro analysis of the liver sinusoid. The modular bioreactor allows i) excellent control of the cell seeding process; ii) cell culture under controlled shear stress stimulus, and; iii) individual analysis of each cell type upon completion of the experiment. The advantages of the bioreactor detailed here are derived from the modification of a commercial porous membrane ...

  9. Realization of Electronically Tunable Current- Mode Multiphase Sinusoidal Oscillators Using CFTAs

    OpenAIRE

    Prungsak Uttaphut

    2012-01-01

    An implementation of current-mode multiphase sinusoidal oscillators is presented. Using CFTA-based lossy integrators, odd and odd/even phase systems can be realized with following advantages. The condition of oscillation and frequency of oscillation can be orthogonally tuned. The high output impedances facilitate easy driving an external load without additional current buffers. The proposed MSOs provide odd or even phase signals that are equally spaced in phase and equal amplitude. The circui...

  10. Synthesis of Voltages of Multiple Uniform PWM, Generated by Trapezoidal and Sinusoidal Functions

    Directory of Open Access Journals (Sweden)

    A. G. Ctryzhniou

    2013-01-01

    Full Text Available The problem of synthesis and qualitative estimation of the harmonic composition of voltages of multiple uniform PWM pulses generated by trapezoidal and sinusoidal functions is considered. Analytical expressions for PWM pulses parameters ai  and ti have been received and they can be used for program-based generation of multiple uniform PWM, determination of n-harmonic magnitude in pulse-width regulation and AC motor operation simulation.

  11. Evaluation of Steel Shear Walls Behavior with Sinusoidal and Trapezoidal Corrugated Plates

    Directory of Open Access Journals (Sweden)

    Emad Hosseinpour

    2015-01-01

    Full Text Available Reinforcement of structures aims to control the input energy of unnatural and natural forces. In the past four decades, steel shear walls are utilized in huge constructions in some seismic countries such as Japan, United States, and Canada to lessen the risk of destructive forces. The steel shear walls are divided into two types: unstiffened and stiffened. In the former, a series of plates (sinusoidal and trapezoidal corrugated with light thickness are used that have the postbuckling field property under overall buckling. In the latter, steel profile belt series are employed as stiffeners with different arrangement: horizontal, vertical, or diagonal in one side or both sides of wall. In the unstiffened walls, increasing the thickness causes an increase in the wall capacity under large forces in tall structures. In the stiffened walls, joining the stiffeners to the wall is costly and time consuming. The ANSYS software was used to analyze the different models of unstiffened one-story steel walls with sinusoidal and trapezoidal corrugated plates under lateral load. The obtained results demonstrated that, in the walls with the same dimensions, the trapezoidal corrugated plates showed higher ductility and ultimate bearing compared to the sinusoidal corrugated plates.

  12. Analysis of Passive Mixing in a Serpentine Microchannel with Sinusoidal Side Walls

    Directory of Open Access Journals (Sweden)

    Muhammad Usman Javaid

    2017-12-01

    Full Text Available Sample mixing is difficult in microfluidic devices because of laminar flow. Micromixers are designed to ensure the optimal use of miniaturized devices. The present study aims to design a chaotic-advection-based passive micromixer with enhanced mixing efficiency. A serpentine-shaped microchannel with sinusoidal side walls was designed, and three cases, with amplitude to wavelength (A/λ ratios of 0.1, 0.15, and 0.2 were investigated. Numerical simulations were conducted using the Navier–Stokes equations, to determine the flow field. The flow was then coupled with the convection–diffusion equation to obtain the species concentration distribution. The mixing performance of sinusoidal walled channels was compared with that of a simple serpentine channel for Reynolds numbers ranging from 0.1 to 50. Secondary flows were observed at high Reynolds numbers that mixed the fluid streams. These flows were dominant in the proposed sinusoidal walled channels, thereby showing better mixing performance than the simple serpentine channel at similar or less mixing cost. Higher mixing efficiency was obtained by increasing the A/λ ratio.

  13. Frequency response evaluation of radial artery catheter-manometer systems: sinusoidal frequency analysis versus flush method.

    Science.gov (United States)

    Schwid, H A

    1988-07-01

    It is well recognized that catheter-manometer systems significantly distort direct radial artery pressure measurements. Sinusoidal frequency analysis and the flush method of assessing the degree of distortion caused by the monitoring system were compared to determine whether these two methods agree in the estimation of natural frequency and damping coefficient. The frequency response of 30 radial artery catheter-manometer systems used for intensive-care unit patients was measured by the flush method and sinusoidal frequency analysis. The monitoring system consisted of a 20-gauge cannula, 150-cm pressure tubing, two plastic stopcocks, a continuous infusion device with fast flush valve, an American Edwards dome, a Hewlett-Packard quartz transducer, and a Hewlett-Packard blood pressure amplifier. Sinusoidal frequency analysis demonstrated second-order underdamped response for all 30 catheter-manometer systems. No secondary resonance peaks were observed up to a frequency of 200 Hz. The measured frequency response demonstrated that the average catheter-manometer system in use in our intensive care unit would cause significant distortion of the radial artery pressure, with the mean natural frequency (fn) of 14.7 +/- 3.7 Hz and the mean damping coefficient (zeta) of 0.24 +/- 0.07. Although the 30 monitoring systems had identical configurations and visible bubbles were carefully removed, a wide range of frequency responses was found (fn = 10.2 to 25.3; zeta = 0.15 to 0.44).(ABSTRACT TRUNCATED AT 250 WORDS)

  14. Intravascular Immune Surveillance by CXCR6+ NKT Cells Patrolling Liver Sinusoids

    Directory of Open Access Journals (Sweden)

    Geissmann Frederic

    2005-01-01

    Full Text Available We examined the in vivo behavior of liver natural killer T cells (NKT cells by intravital fluorescence microscopic imaging of mice in which a green fluorescent protein cDNA was used to replace the gene encoding the chemokine receptor CXCR6. NKT cells, which account for most CXCR6+ cells in liver, were found to crawl within hepatic sinusoids at 10-20 µm/min and to stop upon T cell antigen receptor activation. CXCR6-deficient mice exhibited a selective and severe reduction of CD1d-reactive NKT cells in the liver and decreased susceptibility to T-cell-dependent hepatitis. CXCL16, the cell surface ligand for CXCR6, is expressed on sinusoidal endothelial cells, and CXCR6 deficiency resulted in reduced survival, but not in altered speed or pattern of patrolling of NKT cells. Thus, NKT cells patrol liver sinusoids to provide intravascular immune surveillance, and CXCR6 contributes to liver-based immune responses by regulating their abundance.

  15. Nonpulsed sinusoidal electromagnetic fields as a noninvasive strategy in bone repair: the effect on human mesenchymal stem cell osteogenic differentiation.

    Science.gov (United States)

    Ledda, Mario; D'Emilia, Enrico; Giuliani, Livio; Marchese, Rodolfo; Foletti, Alberto; Grimaldi, Settimio; Lisi, Antonella

    2015-02-01

    In vivo control of osteoblast differentiation is an important process needed to maintain the continuous supply of mature osteoblast cells for growth, repair, and remodeling of bones. The regulation of this process has also an important and significant impact on the clinical strategies and future applications of cell therapy. In this article, we studied the effect of nonpulsed sinusoidal electromagnetic field radiation tuned at calcium-ion cyclotron frequency of 50 Hz exposure treatment for bone differentiation of human mesenchymal stem cells (hMSCs) alone or in synergy with dexamethasone, their canonical chemical differentiation agent. Five days of continuous exposure to calcium-ion cyclotron resonance affect hMSC proliferation, morphology, and cytoskeletal actin reorganization. By quantitative real-time polymerase chain reaction, we also observed an increase of osteoblast differentiation marker expression such as Runx2, alkaline phosphatase (ALP), osteocalcin (OC), and osteopontin (OPN) together with the osteoprotegerin mRNA modulation. Moreover, in these cells, the increase of the protein expression of OPN and ALP was also demonstrated. These results demonstrate bone commitment of hMSCs through a noninvasive and biocompatible differentiating physical agent treatment and highlight possible applications in new regenerative medicine protocols.

  16. Numerical investigation of J-characterization of growing crack tips

    International Nuclear Information System (INIS)

    Nilsson, F.

    1992-01-01

    Two different geometries, a centrally cracked panel and a three-point bend bar, are modelled with aid of the finite element program ABAQUS. Elastic-plastic behaviour with a realistic linear hardening modulus is assumed. By simulation of the growth with the aid of nodal relaxation, the J-value for a remote path around the growing tip is obtained for some different local-crack growth histories. The J F -value is compared to the J D -value that results if the crack tip is assumed to be stationary at the current length. It is found that the J C - and J F -values agree well for crack growth histories satisfying the criteria for J-characterization. However, after examination of the crack surface displacements it was found that the results for the bend geometry and the tension geometry, respectively, did not coincide for corresponding J-values, except at low load levels. This raises doubt about the abilities of J to characterize the state at a growing tip. (orig.)

  17. Windows 8 visual quick tips

    CERN Document Server

    McFedries, Paul

    2012-01-01

    Easy-in, easy-out format covers all the bells and whistles of Windows 8 If you want to learn how to work smarter and faster in Microsoft's Windows 8 operating system, this easy-to-use, compact guide delivers the goods. Designed for visual learners, it features short explanations and full-color screen shots on almost every page, and it's packed with timesaving tips and helpful productivity tricks. From enhancing performance and managing digital content to setting up security and much more, this handy guide will help you get more out of Windows 8. Uses full-color screen shots and short, step-by-

  18. Twitter Tips, Tricks, and Tweets

    CERN Document Server

    McFedries, Paul

    2010-01-01

    Maximize your fun and boost your productivity with this updated, full-color guide to tantalizing Twitter tips!. The popularity of Twitter continues to soar, and is fast becoming the most popular social networking site online. Whether you're looking to learn how to set up an account for the first time or are on the prowl for some cool third-party Twitter apps, this full-color guide will boost your entire Twitter experience. Allowing you to communicate with fellow Twitters within a 140-character limit, this fun and fascinating social networking tool is easier than maintaining a blog and quicker

  19. TIP60 represses telomerase expression by inhibiting Sp1 binding to the TERT promoter.

    Directory of Open Access Journals (Sweden)

    Deepa Rajagopalan

    2017-10-01

    Full Text Available HIV1-TAT interactive protein (TIP60 is a haploinsufficient tumor suppressor. However, the potential mechanisms endowing its tumor suppressor ability remain incompletely understood. It plays a vital role in virus-induced cancers where TIP60 down-regulates the expression of human papillomavirus (HPV oncoprotein E6 which in turn destabilizes TIP60. This intrigued us to identify the role of TIP60, in the context of a viral infection, where it is targeted by oncoproteins. Through an array of molecular biology techniques such as Chromatin immunoprecipitation, expression analysis and mass spectrometry, we establish the hitherto unknown role of TIP60 in repressing the expression of the catalytic subunit of the human telomerase complex, TERT, a key driver for immortalization. TIP60 acetylates Sp1 at K639, thus inhibiting Sp1 binding to the TERT promoter. We identified that TIP60-mediated growth suppression of HPV-induced cervical cancer is mediated in part due to TERT repression through Sp1 acetylation. In summary, our study has identified a novel substrate for TIP60 catalytic activity and a unique repressive mechanism acting at the TERT promoter in virus-induced malignancies.

  20. Rebleeding rates following TIPS for variceal hemorrhage in the Viatorr era: TIPS alone versus TIPS with variceal embolization.

    Science.gov (United States)

    Gaba, Ron C; Bui, James T; Cotler, Scott J; Kallwitz, Eric R; Mengin, Olga T; Martinez, Brandon K; Berkes, Jaime L; Carrillo, Tami C; Knuttinen, M Grace; Owens, Charles A

    2010-08-06

    To compare rebleeding rates following treatment of variceal hemorrhage with TIPS alone versus TIPS with variceal embolization in the covered stent-graft era. In this retrospective study, 52 patients (M:F 29:23, median age 52 years) with hepatic cirrhosis and variceal hemorrhage underwent TIPS insertion between 2003 and 2008. Median Child-Pugh and MELD scores were 8.5 and 13.5. Generally, 10-mm diameter TIPS were created using covered stent-grafts (Viatorr; W.L. Gore and Associates, Flagstaff, AZ). A total of 37 patients underwent TIPS alone, while 15 patients underwent TIPS with variceal embolization. The rates of rebleeding and survival were compared. All TIPS were technically successful. Median portosystemic pressure gradient reductions were 13 versus 11 mmHg in the embolization and non-embolization groups. There were no statistically significant differences in Child-Pugh and MELD score, or portosystemic pressure gradients between each group. A trend toward increased rebleeding was present in the non-embolization group, where 8/37 (21.6%) patients rebled while 1/15 (6.7%) patients in the TIPS with embolization group rebled (P = 0.159) during median follow-up periods of 199 and 252 days (P = 0.374). Rebleeding approached statistical significance among patients with acute hemorrhage, where 8/32 (25%) versus 0/14 (0%) rebled in the non-embolization and embolization groups (P = 0.055). A trend toward increased bleeding-related mortality was seen in the non-embolization group (P = 0.120). TIPS alone showed a high incidence of rebleeding in this series, whereas TIPS with variceal embolization resulted in reduced recurrent hemorrhage. The efficacy of embolization during TIPS performed for variceal hemorrhage versus TIPS alone should be further compared with larger prospective randomized trials.

  1. Numerical Analysis of Joule Heating Behavior and Residual Compressive Stress around Crack Tip under High Electric Load

    Directory of Open Access Journals (Sweden)

    Thomas Jin-Chee Liu

    2017-01-01

    Full Text Available This paper discusses the Joule heating effect and residual compressive stress near the crack tip under the electro-thermo-structural coupling state. For the crack tip field, the compressive condition is important for retarding or stopping the crack growth.

  2. Production of factor VIII by human liver sinusoidal endothelial cells transplanted in immunodeficient uPA mice.

    Directory of Open Access Journals (Sweden)

    Marina E Fomin

    Full Text Available Liver sinusoidal endothelial cells (LSECs form a semi-permeable barrier between parenchymal hepatocytes and the blood. LSECs participate in liver metabolism, clearance of pathological agents, immunological responses, architectural maintenance of the liver and synthesis of growth factors and cytokines. LSECs also play an important role in coagulation through the synthesis of Factor VIII (FVIII. Herein, we phenotypically define human LSECs isolated from fetal liver using flow cytometry and immunofluorescence microscopy. Isolated LSECs were cultured and shown to express endothelial markers and markers specific for the LSEC lineage. LSECs were also shown to engraft the liver when human fetal liver cells were transplanted into immunodeficient mice with liver specific expression of the urokinase-type plasminogen activator (uPA transgene (uPA-NOG mice. Engrafted cells expressed human Factor VIII at levels approaching those found in human plasma. We also demonstrate engraftment of adult LSECs, as well as hepatocytes, transplanted into uPA-NOG mice. We propose that overexpression of uPA provides beneficial conditions for LSEC engraftment due to elevated expression of the angiogenic cytokine, vascular endothelial growth factor. This work provides a detailed characterization of human midgestation LSECs, thereby providing the means for their purification and culture based on their expression of CD14 and CD32 as well as a lack of CD45 expression. The uPA-NOG mouse is shown to be a permissive host for human LSECs and adult hepatocytes, but not fetal hepatoblasts. Thus, these mice provide a useful model system to study these cell types in vivo. Demonstration of human FVIII production by transplanted LSECs encourages further pursuit of LSEC transplantation as a cellular therapy for the treatment of hemophilia A.

  3. 3D hepatic cultures simultaneously maintain primary hepatocyte and liver sinusoidal endothelial cell phenotypes.

    Directory of Open Access Journals (Sweden)

    Yeonhee Kim

    Full Text Available Developing in vitro engineered hepatic tissues that exhibit stable phenotype is a major challenge in the field of hepatic tissue engineering. However, the rapid dedifferentiation of hepatic parenchymal (hepatocytes and non-parenchymal (liver sinusoidal endothelial, LSEC cell types when removed from their natural environment in vivo remains a major obstacle. The primary goal of this study was to demonstrate that hepatic cells cultured in layered architectures could preserve or potentially enhance liver-specific behavior of both cell types. Primary rat hepatocytes and rat LSECs (rLSECs were cultured in a layered three-dimensional (3D configuration. The cell layers were separated by a chitosan-hyaluronic acid polyelectrolyte multilayer (PEM, which served to mimic the Space of Disse. Hepatocytes and rLSECs exhibited several key phenotypic characteristics over a twelve day culture period. Immunostaining for the sinusoidal endothelial 1 antibody (SE-1 demonstrated that rLSECs cultured in the 3D hepatic model maintained this unique feature over twelve days. In contrast, rLSECs cultured in monolayers lost their phenotype within three days. The unique stratified structure of the 3D culture resulted in enhanced heterotypic cell-cell interactions, which led to improvements in hepatocyte functions. Albumin production increased three to six fold in the rLSEC-PEM-Hepatocyte cultures. Only rLSEC-PEM-Hepatocyte cultures exhibited increasing CYP1A1/2 and CYP3A activity. Well-defined bile canaliculi were observed only in the rLSEC-PEM-Hepatocyte cultures. Together, these data suggest that rLSEC-PEM-Hepatocyte cultures are highly suitable models to monitor the transformation of toxins in the liver and their transport out of this organ. In summary, these results indicate that the layered rLSEC-PEM-hepatocyte model, which recapitulates key features of hepatic sinusoids, is a potentially powerful medium for obtaining comprehensive knowledge on liver metabolism

  4. Impact Testing and Simulation of a Sinusoid Foam Sandwich Energy Absorber

    Science.gov (United States)

    Jackson, Karen E.; Fasanella, Edwin L; Littell, Justin D.

    2015-01-01

    A sinusoidal-shaped foam sandwich energy absorber was developed and evaluated at NASA Langley Research Center through multi-level testing and simulation performed under the Transport Rotorcraft Airframe Crash Testbed (TRACT) research project. The energy absorber, designated the "sinusoid," consisted of hybrid carbon- Kevlar® plain weave fabric face sheets, two layers for each face sheet oriented at +/-45deg with respect to the vertical or crush direction, and a closed-cell ELFOAM(TradeMark) P200 polyisocyanurate (2.0-lb/ft3) foam core. The design goal for the energy absorber was to achieve an average floor-level acceleration of between 25- and 40-g during the full-scale crash test of a retrofitted CH-46E helicopter airframe, designated TRACT 2. Variations in the design were assessed through quasi-static and dynamic crush testing of component specimens. Once the design was finalized, a 5-ft-long subfloor beam was fabricated and retrofitted into a barrel section of a CH-46E helicopter. A vertical drop test of the barrel section was conducted onto concrete to evaluate the performance of the energy absorber prior to retrofit into TRACT 2. Finite element models were developed of all test articles and simulations were performed using LSDYNA ®, a commercial nonlinear explicit transient dynamic finite element code. Test analysis results are presented for the sinusoid foam sandwich energy absorber as comparisons of load-displacement and acceleration-time-history responses, as well as predicted and experimental structural deformations and progressive damage for each evaluation level (component testing through barrel section drop testing).

  5. Unique cell type-specific junctional complexes in vascular endothelium of human and rat liver sinusoids.

    Directory of Open Access Journals (Sweden)

    Cyrill Géraud

    Full Text Available Liver sinusoidal endothelium is strategically positioned to control access of fluids, macromolecules and cells to the liver parenchyma and to serve clearance functions upstream of the hepatocytes. While clearance of macromolecular debris from the peripheral blood is performed by liver sinusoidal endothelial cells (LSECs using a delicate endocytic receptor system featuring stabilin-1 and -2, the mannose receptor and CD32b, vascular permeability and cell trafficking are controlled by transcellular pores, i.e. the fenestrae, and by intercellular junctional complexes. In contrast to blood vascular and lymphatic endothelial cells in other organs, the junctional complexes of LSECs have not yet been consistently characterized in molecular terms. In a comprehensive analysis, we here show that LSECs express the typical proteins found in endothelial adherens junctions (AJ, i.e. VE-cadherin as well as α-, β-, p120-catenin and plakoglobin. Tight junction (TJ transmembrane proteins typical of endothelial cells, i.e. claudin-5 and occludin, were not expressed by rat LSECs while heterogenous immunreactivity for claudin-5 was detected in human LSECs. In contrast, junctional molecules preferentially associating with TJ such as JAM-A, B and C and zonula occludens proteins ZO-1 and ZO-2 were readily detected in LSECs. Remarkably, among the JAMs JAM-C was considerably over-expressed in LSECs as compared to lung microvascular endothelial cells. In conclusion, we show here that LSECs form a special kind of mixed-type intercellular junctions characterized by co-occurrence of endothelial AJ proteins, and of ZO-1 and -2, and JAMs. The distinct molecular architecture of the intercellular junctional complexes of LSECs corroborates previous ultrastructural findings and provides the molecular basis for further analyses of the endothelial barrier function of liver sinusoids under pathologic conditions ranging from hepatic inflammation to formation of liver metastasis.

  6. U.S. Tech Cities are at a Tipping Point

    OpenAIRE

    Singh, Paul; Langellier, Mike

    2017-01-01

    "U.S. Tech Cities Are at a Tipping Point" The growth of tech in the United States has disrupted not only industries and business models, it's also disrupting cities, often times with very challenging consequences for millions of people who live in them. Join a discussion with Mike Langellier, CEO TechPoint--a tech ecosystem growth accelerator--and Paul Sing--serial entrepreneur and venture capital investor who traveled to 70 cities in the past year--to learn what is happening, where, why, and...

  7. Generation of hyperchaos from the Chen-Lee system via sinusoidal perturbation

    Energy Technology Data Exchange (ETDEWEB)

    Tam, L.M. [Department of Electromechanical Engineering, Faculty of Science and Technology, University of Macau, Av. Padre Thomas Pereira S.J., Taipa, Macau (China)], E-mail: fstlmt@umac.mo; Chen, J.H. [Department of Mechanical Engineering, Chung Hua University, Hsinchu, Taiwan (China); Chen, H.K. [Department of Mechanical Engineering, Hsiuping Institute of Technology, Taichung, Taiwan (China); Wai Meng Si Tou [Department of Electromechanical Engineering, Faculty of Science and Technology, University of Macau, Av. Padre Thomas Pereira S.J., Taipa, Macau (China)

    2008-11-15

    A system with more than one positive Lyapunov exponent can be classified as a hyperchaotic system. In this study, a sinusoidal perturbation was designed for generating hyperchaos from the Chen-Lee chaotic system. The hyperchaos was identified by the existence of two positive Lyapunov exponents and bifurcation diagrams. The system is hyperchaotic in several different regions of the parameters c, {epsilon}, and {omega}. It was found that this method not only can enhance or suppress chaotic behavior, but also induces chaos in non-chaotic parameter ranges. In addition, two interesting dynamical behaviors, Hopf bifurcation and intermittency, were also found in this study.

  8. Analysis and Implementation of Multiple Bionic Motion Patterns for Caterpillar Robot Driven by Sinusoidal Oscillator

    Directory of Open Access Journals (Sweden)

    Yanhe Zhu

    2014-05-01

    Full Text Available Articulated caterpillar robot has various locomotion patterns—which make it adaptable to different tasks. Generally, the researchers have realized undulatory (transverse wave and simple rolling locomotion. But many motion patterns are still unexplored. In this paper, peristaltic locomotion and various additional rolling patterns are achieved by employing sinusoidal oscillator with fixed phase difference as the joint controller. The usefulness of the proposed method is verified using simulation and experiment. The design parameters for different locomotion patterns have been calculated that they can be replicated in similar robots immediately.

  9. New Results on Single-Channel Speech Separation Using Sinusoidal Modeling

    DEFF Research Database (Denmark)

    Mowlaee, Pejman; Christensen, Mads Græsbøll; Jensen, Søren Holdt

    2011-01-01

    We present new results on single-channel speech separation and suggest a new separation approach to improve the speech quality of separated signals from an observed mix- ture. The key idea is to derive a mixture estimator based on sinusoidal parameters. The proposed estimator is aimed at finding...... the proposed method over other methods are confirmed by employing perceptual evaluation of speech quality (PESQ) as an objective measure and a MUSHRA listening test as a subjective evaluation for both speaker-dependent and gender-dependent scenarios....

  10. A Statistical and Spectral Model for Representing Noisy Sounds with Short-Time Sinusoids

    Directory of Open Access Journals (Sweden)

    Myriam Desainte-Catherine

    2005-07-01

    Full Text Available We propose an original model for noise analysis, transformation, and synthesis: the CNSS model. Noisy sounds are represented with short-time sinusoids whose frequencies and phases are random variables. This spectral and statistical model represents information about the spectral density of frequencies. This perceptually relevant property is modeled by three mathematical parameters that define the distribution of the frequencies. This model also represents the spectral envelope. The mathematical parameters are defined and the analysis algorithms to extract these parameters from sounds are introduced. Then algorithms for generating sounds from the parameters of the model are presented. Applications of this model include tools for composers, psychoacoustic experiments, and pedagogy.

  11. Voltage-Mode Four-Phase Sinusoidal Generator and Its Useful Extensions

    Directory of Open Access Journals (Sweden)

    Sudhanshu Maheshwari

    2013-01-01

    Full Text Available This paper introduces a new voltage-mode second-order sinusoidal generator circuit with four active elements and six passive elements, including grounded capacitors. The frequency and condition of oscillation can be independently controlled. The effect of active element’s nonidealities and parasitic effects is also studied; the proposed topology is good in absorbing several parasitic elements involved with the active elements. The circuit is advantageous for generating high frequency signals which is demonstrated for 25 MHz outputs. Several circuit extensions are also given which makes the new proposal useful for real circuit adoption. The proposed theory is validated through simulation results.

  12. Exact solution of unsteady flow generated by sinusoidal pressure gradient in a capillary tube

    Directory of Open Access Journals (Sweden)

    M. Abdulhameed

    2015-12-01

    Full Text Available In this paper, the mathematical modeling of unsteady second grade fluid in a capillary tube with sinusoidal pressure gradient is developed with non-homogenous boundary conditions. Exact analytical solutions for the velocity profiles have been obtained in explicit forms. These solutions are written as the sum of the steady and transient solutions for small and large times. For growing times, the starting solution reduces to the well-known periodic solution that coincides with the corresponding solution of a Newtonian fluid. Graphs representing the solutions are discussed.

  13. Investigation of phase error correction for digital sinusoidal phase-shifting fringe projection profilometry

    Science.gov (United States)

    Ma, S.; Quan, C.; Zhu, R.; Tay, C. J.

    2012-08-01

    Digital sinusoidal phase-shifting fringe projection profilometry (DSPFPP) is a powerful tool to reconstruct three-dimensional (3D) surface of diffuse objects. However, a highly accurate profile is often hindered by nonlinear response, color crosstalk and imbalance of a pair of digital projector and CCD/CMOS camera. In this paper, several phase error correction methods, such as Look-Up-Table (LUT) compensation, intensity correction, gamma correction, LUT-based hybrid method and blind phase error suppression for gray and color-encoded DSPFPP are described. Experimental results are also demonstrated to evaluate the effectiveness of each method.

  14. OTRA based second and third order sinusoidal oscillators and their phase noise performance

    Science.gov (United States)

    Komanapalli, Gurumurthy; Pandey, Neeta; Pandey, Rajeshwari

    2017-07-01

    In this paper operational transresistance amplifier (OTRA) based second and third order sinusoidal oscillators are proposed. The proposed second order oscillator is designed using single OTRA based Sallen Key low pass filter structure and third order oscillator is obtained by cascading three low pass filters and placing in a loop. The non-ideality and phase noise analyses of the circuits are also presented with necessary mathematical formulations. Workability of the proposed oscillators are verified through PSPICE simulations using 0.18µm AGILENT CMOS process parameters. The total harmonic distortion (THD) for proposed second order and third order oscillators are found as 3.27% and 0.631% respectively.

  15. Theory of sinusoidal modulation of the resonant neutron scattering in high-temperature superconductors

    International Nuclear Information System (INIS)

    Li Tao

    2001-01-01

    A model with interlayer pairing is proposed to explain the sinusoidal modulation of the resonant neutron scattering in high-temperature superconductors. It is found that the interlayer pairing has s-wave symmetry in the CuO 2 plane and has comparable magnitude with the d-wave intralayer pairing. It is also found that the interlayer pairing mainly affects momentum close to the hot spots on the Fermi surface while its effect on the gap nodes is negligible. It is pointed out that these characteristics of the interlayer pairing can be understood in a model in which the superconducting pairing originates from the exchange of the antiferromagnetic spin fluctuation

  16. Application of Lattice-Boltzmann method and analysis of fluid flow between two sinusoidal plates

    Directory of Open Access Journals (Sweden)

    Marković Jelena Đ.

    2010-01-01

    Full Text Available This paper is concerned with numerical study of fluid flow through a pair of corrugated platest. The aim was to observe and understand the behavior of the flow and vortex formation through channels where the fluid is subjected to a periodic increase and decrease in cross-section area. The plates modeled for the study had sinusoidal profiles. A pair of plates with 180° phase shift was simulated in two-dimensional spaces. The Reynolds number was a function of the average plate spacing (Havg and the laminar flow velocity and it was in the range between 200 and 1000.

  17. Measuring Fan-Blade-Tip Displacements

    Science.gov (United States)

    Berry, Robert F., Jr.

    1988-01-01

    Magnets and Hall-effect transducers used to monitor tip-to-shroud clearances. Mounting permanent magnet in end of fan blade and monitoring tip-to-shroud distance by use of output of Hall-effect transducers affixed to surface of shroud. Transducers provide real-time information. By placing magnets in each fan-blade tip, complete set monitored sequentially as each blade rotates past sensor. Application in many rotating machines, providing surrounding materials nonmagnetic and temperatures not severe.

  18. Fatigue crack growth in mixed mode I+III+III non proportional loading conditions in a 316 stainless steel, experimental analysis and modelization of the effects of crack tip plasticity

    International Nuclear Information System (INIS)

    Fremy, F.

    2012-01-01

    This thesis deals with fatigue crack growth in non-proportional variable amplitude mixed mode I + II + III loading conditions and analyses the effects of internal stresses stemming from the confinement of the plastic zone in small scale yielding conditions. The tests showed that there are antagonistic long-distance and short-distance effects of the loading history on fatigue crack growth. The shape of loading path, and not only the maximum and minimum values in this path, is crucial and, by comparison, the effects of contact and friction are of lesser importance. Internal stresses play a major role on the fatigue crack growth rate and on the crack path. An approach was developed to analyze the elastic-plastic behavior of a representative section of the crack front using the FEA. A model reduction technic is used to extract the relevant information from the FE results. To do so, the velocity field is partitioned into mode I, II, III elastic and plastic components, each component being characterized by an intensity factor and a fixed spatial distribution. The calculations were used to select seven loading paths in I + II and I + II + III mixed mode conditions, which all have the same amplitudes for each mode, the same maximum, minimum and average values. These paths are supposed to be equivalent in the sense of common failure criteria, but differ significantly when the elastic-plastic behavior of the material is accounted for. The results of finite element simulations and of simulations using a simplified model proposed in this thesis are both in agreement with experimental results. The approach was also used to discuss the role of mode III loading steps. Since the material behavior is nonlinear, the nominal loading direction does not coincide with the plastic flow direction. Adding a mode III loading step in a mode I+II fatigue cycle, may, in some cases, significantly modify the behaviour of the crack (crack growth rate, crack path and plastic flow). (author)

  19. Controlled generation of nonlinear resonances through sinusoidal lattice modes in Bose–Einstein condensate

    International Nuclear Information System (INIS)

    Das, Priyam; Panigrahi, Prasanta K

    2015-01-01

    We study Bose–Einstein condensate in the combined presence of time modulated optical lattice and harmonic trap in the mean-field approach. Through the self-similar method, we show the existence of sinusoidal lattice modes in this inhomogeneous system, commensurate with the lattice potential. A significant advantage of this system is wide tunability of the parameters through chirp management. The combined effect of the interaction, harmonic trap and lattice potential leads to the generation of nonlinear resonances, exactly where the matter wave changes its direction. When the harmonic trap is switched off, the BEC undergoes a nonlinear compression for the static optical lattice potential. For better understanding of chirp management and the nature of the sinusoidal excitation, we investigate the energy spectrum of the condensate, which clearly reveals the generation of nonlinear resonances in the appropriate regime. We have also identified a classical dynamical phase transition occurring in the system, where loss of superfluidity takes the superfluid phase to an insulating state. (paper)

  20. The 3-D alignment of objects in dynamic PET scans using filtered sinusoidal trajectories of sinogram

    International Nuclear Information System (INIS)

    Kostopoulos, Aristotelis E.; Happonen, Antti P.; Ruotsalainen, Ulla

    2006-01-01

    In this study, our goal is to employ a novel 3-D alignment method for dynamic positron emission tomography (PET) scans. Because the acquired data (i.e. sinograms) often contain noise considerably, filtering of the data prior to the alignment presumably improves the final results. In this study, we utilized a novel 3-D stackgram domain approach. In the stackgram domain, the signals along the sinusoidal trajectory signals of the sinogram can be processed separately. In this work, we performed angular stackgram domain filtering by employing well known 1-D filters: the Gaussian low-pass filter and the median filter. In addition, we employed two wavelet de-noising techniques. After filtering we performed alignment of objects in the stackgram domain. The local alignment technique we used is based on similarity comparisons between locus vectors (i.e. the signals along the sinusoidal trajectories of the sinogram) in a 3-D neighborhood of sequences of the stackgrams. Aligned stackgrams can be transformed back to sinograms (Method 1), or alternatively directly to filtered back-projected images (Method 2). In order to evaluate the alignment process, simulated data with different kinds of additive noises were used. The results indicated that the filtering prior to the alignment can be important concerning the accuracy

  1. Biliary obstruction dissipates bioelectric sinusoidal-canalicular barrier without altering taurocholate uptake

    International Nuclear Information System (INIS)

    Cotting, J.; Zysset, T.; Reichen, J.

    1989-01-01

    To study immediate events during extrahepatic cholestasis, we investigated the effect of short-term biliary obstruction on the bioelectrical sinusoidal-canalicular barrier in the rat using molecular weight-matched uncharged and negatively charged inert solute pairs. The bioelectrical barrier averaged -22 +/- 5 and -18 +/- 4 mV (NS) using the pair carboxy-/methoxyinulin and ferrocyanide/sucrose, respectively. After a 20-min biliary obstruction both decreased by 61 and 11%, respectively, but only the large molecular weight pair (the inulins) returned to base line after release of the obstruction. Inert solute clearances were increased after short biliary obstruction depending on molecular size and negative charge (ferrocyanide greater than sucrose greater than carboxyinulin greater than inulin), suggesting that both permeability and bioelectrical barriers were affected by obstruction. The hepatic extraction in vivo of a passively transported drug not excreted into bile (D-propranolol) was not affected by obstruction, whereas that of an actively transported drug (glycocholate) decreased from 66 +/- 8 to 41 +/- 20% during biliary obstruction (P less than 0.01). Unidirectional transfer of glycocholate was not affected by short-term biliary obstruction in the situ perfused rat liver; however, 2 min after [14C]glycocholate administration, increased return was observed in hepatic venous effluent in obstructed animals. Our findings demonstrate a loss of the bioelectrical barrier immediately after short-term biliary obstruction. Decreased hepatic extraction in the view of unaltered sinusoidal uptake demonstrates regurgitation of bile into blood during short-term biliary obstruction

  2. Automatic fringe enhancement with novel bidimensional sinusoids-assisted empirical mode decomposition.

    Science.gov (United States)

    Wang, Chenxing; Kemao, Qian; Da, Feipeng

    2017-10-02

    Fringe-based optical measurement techniques require reliable fringe analysis methods, where empirical mode decomposition (EMD) is an outstanding one due to its ability of analyzing complex signals and the merit of being data-driven. However, two challenging issues hinder the application of EMD in practical measurement. One is the tricky mode mixing problem (MMP), making the decomposed intrinsic mode functions (IMFs) have equivocal physical meaning; the other is the automatic and accurate extraction of the sinusoidal fringe from the IMFs when unpredictable and unavoidable background and noise exist in real measurements. Accordingly, in this paper, a novel bidimensional sinusoids-assisted EMD (BSEMD) is proposed to decompose a fringe pattern into mono-component bidimensional IMFs (BIMFs), with the MMP solved; properties of the resulted BIMFs are then analyzed to recognize and enhance the useful fringe component. The decomposition and the fringe recognition are integrated and the latter provides a feedback to the former, helping to automatically stop the decomposition to make the algorithm simpler and more reliable. A series of experiments show that the proposed method is accurate, efficient and robust to various fringe patterns even with poor quality, rendering it a potential tool for practical use.

  3. A novel modular bioreactor to in vitro study the hepatic sinusoid.

    Directory of Open Access Journals (Sweden)

    Xavi Illa

    Full Text Available We describe a unique, versatile bioreactor consisting of two plates and a modified commercial porous membrane suitable for in vitro analysis of the liver sinusoid. The modular bioreactor allows i excellent control of the cell seeding process; ii cell culture under controlled shear stress stimulus, and; iii individual analysis of each cell type upon completion of the experiment. The advantages of the bioreactor detailed here are derived from the modification of a commercial porous membrane with an elastomeric wall specifically moulded in order to define the cell culture area, to act as a gasket that will fit into the bioreactor, and to provide improved mechanical robustness. The device presented herein has been designed to simulate the in vivo organization of a liver sinusoid and tested by co-culturing endothelial cells (EC and hepatic stellate cells (HSC. The results show both an optimal morphology of the endothelial cells as well as an improvement in the phenotype of stellate cells, most probably due to paracrine factors released from endothelial cells. This device is proposed as a versatile, easy-to-use co-culture system that can be applied to biomedical research of vascular systems, including the liver.

  4. CFD study on NACA 4415 airfoil implementing spherical and sinusoidal Tubercle Leading Edge.

    Directory of Open Access Journals (Sweden)

    S M A Aftab

    Full Text Available The Humpback whale tubercles have been studied for more than a decade. Tubercle Leading Edge (TLE effectively reduces the separation bubble size and helps in delaying stall. They are very effective in case of low Reynolds number flows. The current Computational Fluid Dynamics (CFD study is on NACA 4415 airfoil, at a Reynolds number 120,000. Two TLE shapes are tested on NACA 4415 airfoil. The tubercle designs implemented on the airfoil are sinusoidal and spherical. A parametric study is also carried out considering three amplitudes (0.025c, 0.05c and 0.075c, the wavelength (0.25c is fixed. Structured mesh is utilized to generate grid and Transition SST turbulence model is used to capture the flow physics. Results clearly show spherical tubercles outperform sinusoidal tubercles. Furthermore experimental study considering spherical TLE is carried out at Reynolds number 200,000. The experimental results show that spherical TLE improve performance compared to clean airfoil.

  5. Aerosol absorption measurement with a sinusoidal phase modulating fiber optic photo thermal interferometer

    Science.gov (United States)

    Li, Shuwang; Shao, Shiyong; Mei, Haiping; Rao, Ruizhong

    2016-10-01

    Aerosol light absorption plays an important role in the earth's atmosphere direct and semi-direct radiate forcing, simultaneously, it also has a huge influence on the visibility impairment and laser engineering application. Although various methods have been developed for measuring aerosol light absorption, huge challenge still remains in precision, accuracy and temporal resolution. The main reason is that, as a part of aerosol light extinction, aerosol light absorption always generates synchronously with aerosol light scattering, and unfortunately aerosol light scattering is much stronger in most cases. Here, a novel photo-thermal interferometry is proposed only for aerosol absorption measurement without disturbance from aerosol scattering. The photo-thermal interferometry consists of a sinusoidal phase-modulating single mode fiber-optic interferometer. The thermal dissipation, caused by aerosol energy from photo-thermal conversion when irritated by pump laser through interferometer, is detected. This approach is completely insensitive to aerosol scattering, and the single mode fiber-optic interferometer is compact, low-cost and insensitive to the polarization shading. The theory of this technique is illustrated, followed by the basic structure of the sinusoidal phase-modulating fiber-optic interferometer and demodulation algorithms. Qualitative and quantitative analysis results show that the new photo-thermal interference is a potential approach for aerosol absorption detection and environmental pollution detection.

  6. Scavenger receptor-mediated endocytosis by sinusoidal cells in rat bone marrow

    International Nuclear Information System (INIS)

    Geoffroy, J.S.

    1987-01-01

    Endocytosis of serum albumin by sinusoidal endothelial cells in rat bone marrow was investigated initially at the ultrastructural level with subsequent biochemical investigation of the specificity mediating this event. Bovine serum albumin adsorbed to 20nm colloidal gold particles (AuBSA) was chosen as the electron microscopic probe. Morphological data strongly suggested that a receptor was involved in uptake of AuBSA. Confirmation of receptor involvement in the uptake of AuBSA by marrow sinusoidal endothelial cells was achieved utilizing an in situ isolated hind limb perfusion protocol in conjunction with unlabeled, radiolabeled, and radio-/colloidal gold labeled probes. The major findings of competition and saturation experiments were: (1) endocytosis of AuBSA was mediated by a receptor for modified/treated serum albumin; (2) endocytosis of formaldehyde-treated serum albumin was mediated by a binding site which may be the same or closely related to the site responsible for the uptake of AuBSA; and (3) endocytosis of native untreated albumin was not mediated by receptor and probably represents fluid-phase pinocitosis

  7. A Comparison Study of Sinusoidal PWM and Space Vector PWM Techniques for Voltage Source Inverter

    Directory of Open Access Journals (Sweden)

    Ömer Türksoy

    2017-06-01

    Full Text Available In this paper, the methods used to control voltage source inverters which have been intensively investigated in recent years are compared. Although the most efficient result is obtained with the least number of switching elements in the inverter topologies, the method used in the switching is at least as effective as the topology. Besides, the selected switching method to control the inverter will play an effective role in suppressing harmonic components while producing the ideal output voltage. There are many derivatives of pulse width modulation techniques that are commonly used to control voltage source inverters. Some of widespread methods are sinusoidal pulse width modulation and space vector pulse width modulation techniques. These modulation techniques used for generating variable frequency and amplitude output voltage in voltage source inverters, have been simulated by using MATLAB/SIMULINK. And, the total harmonic distortions of the output voltages are compared. As a result of simulation studies, sinusoidal pulse width modulation has been found to have more total harmonic distortion in output voltages of voltage source inverters in the simulation. Space vector pulse width modulation has been shown to produce a more efficient output voltage with less total harmonic distortion.

  8. The tip of the iceberg

    DEFF Research Database (Denmark)

    Bjørst, Lill Rastad

    2010-01-01

      Abstract: The tip of the iceberg: Ice as a nonhuman actor of the climate change debate   The global climate change debate has the Arctic as a core region of concern and ice has become a central aspect of discourses. This article discusses ice representations from six different contexts linked...... to the 2009 United Nations Climate Change Conference (COP15) in Copenhagen. The author argues that even though the discussions often seem to be centred on ice alone, the latter gets inscribed in narratives and metaphors which have wider implications for how the Arctic and its Indigenous peoples...... are represented. Ice becomes a nonhuman actor, framing the discussions, acting in specific ways, and linking hybrid networks. Indeed it is used in diverse platforms by scientists, politicians, governments, NGOs, as well as Inuit hunters and fishermen...

  9. CFD analysis of cloud cavitation on three tip-modified propellers with systematically varied tip geometry

    DEFF Research Database (Denmark)

    Shin, K. W.; Andersen, Poul

    2015-01-01

    The blade tip loading is often reduced as an effort to restrain sheet and tip vortex cavitation in the design of marine propellers. This CFD analysis demonstrates that an excessive reduction of the tip loading can cause cloud cavitation responsible for much of noise and surface erosion. Detached...

  10. Observations on Hydride Structures at the Tip of Arrested Cracks Grown under Conditions of Delayed Hydride Cracking

    International Nuclear Information System (INIS)

    Pettersson, Kjell; Oskarsson, Magnus; Bergqvist, Hans

    2003-04-01

    One sample of Zr2.5%Nb and one sample of cold worked and stress relieved Zircaloy-4 which have been tested for hydrogen induced crack growth have been examined in the crack tip region with the aim of determining the mechanism behind the growth of cracks. The proposed mechanisms are brittle failure of a crack tip hydride and hydrogen enhanced localized shear. The examinations were done by TEM and SEM. However attempts to produce a TEM specimen with a thinned region at the tip of the crack were unsuccessful in both samples. One feature observed in the Zr2.5%Nb material may however be an indication of intense shear deformation at the tip of the crack. On the other hand all observations on the Zircaloy-4 sample indicate precipitation of hydrides ahead of the crack tip and the presence of hydrides on the crack flanks

  11. Safety Tips: Basketball (For Parents)

    Science.gov (United States)

    [Skip to Content] for Parents Parents site Sitio para padres General Health Growth & Development Infections Diseases & Conditions Pregnancy & Baby Nutrition & Fitness Emotions & Behavior School & Family ...

  12. Safety Tips: Baseball (For Parents)

    Science.gov (United States)

    [Skip to Content] for Parents Parents site Sitio para padres General Health Growth & Development Infections Diseases & Conditions Pregnancy & Baby Nutrition & Fitness Emotions & Behavior School & Family ...

  13. Twelve Tips for Effective Electronic Presentation.

    Science.gov (United States)

    Crosby, Joy

    1994-01-01

    Offers 12 tips for effective electronic presentation. This article is intended for readers who may be considering using electronic presentation for the first time. Offers reasons for its popularity and occasions when it may be used. The tips offer assistance in the design and presentation of electronic material. (LZ)

  14. Economics of tipping the climate dominoes

    Science.gov (United States)

    Lemoine, Derek; Traeger, Christian P.

    2016-05-01

    Greenhouse gas emissions can trigger irreversible regime shifts in the climate system, known as tipping points. Multiple tipping points affect each other’s probability of occurrence, potentially causing a `domino effect’. We analyse climate policy in the presence of a potential domino effect. We incorporate three different tipping points occurring at unknown thresholds into an integrated climate-economy model. The optimal emission policy considers all possible thresholds and the resulting interactions between tipping points, economic activity, and policy responses into the indefinite future. We quantify the cost of delaying optimal emission controls in the presence of uncertain tipping points and also the benefit of detecting when individual tipping points have been triggered. We show that the presence of these tipping points nearly doubles today’s optimal carbon tax and reduces peak warming along the optimal path by approximately 1 °C. The presence of these tipping points increases the cost of delaying optimal policy until mid-century by nearly 150%.

  15. Liver sinusoidal endothelial cells contribute to CD8 T cell tolerance toward circulating carcinoembryonic antigen in mice.

    Science.gov (United States)

    Höchst, Bastian; Schildberg, Frank A; Böttcher, Jan; Metzger, Christina; Huss, Sebastian; Türler, Andreas; Overhaus, Markus; Knoblich, Andreas; Schneider, Berthold; Pantelis, Dimitrios; Kurts, Christian; Kalff, Jörg C; Knolle, Percy; Diehl, Linda

    2012-11-01

    Immunity against cancer is impeded by local mechanisms promoting development of tumor-specific T cell tolerance, such as regulatory T cells, myeloid-derived suppressor cells, or immunosuppressive factors in the tumor microenvironment. The release of soluble antigens, such as carcinoembryonic antigen (CEA) from colorectal carcinoma (CRC) cells, has been investigated for diagnostic purposes, but not for its immunological consequences. Here, we address the question of whether soluble CEA influences tumor-specific immunity. Mice were injected with soluble CEA protein, and CEA-specific CD8 T cells were analyzed for their phenotype and functionality by means of restimulation ex vivo or antitumor efficacy in vivo. We furthermore characterized the CD8 T cell population in peripheral blood mononuclear cell (PBMCs) from healthy donors and colorectal carcinoma patients. In mice, circulating CEA was preferentially taken up in a mannose receptor-dependent manner and cross-presented by liver sinusoidal endothelial cells, but not dendritic cells, to CD8 T cells. Such systemically circulating CEA promoted tolerization of CEA-specific CD8 T cells in the endogenous T cell repertoire through the coinhibitory molecule B7H1. These CD8 T cells were not deleted but were rendered nonresponsive to antigen-specific stimulation and failed to control growth of CEA-expressing tumor cells. These nonresponsive CD8 T cells were phenotypically similar to central memory T cells being CD44(high) CD62L(high) CD25(neg) . We found T cells with a similar phenotype in PBMCs of healthy donors and at increased frequency also in patients with colorectal carcinoma. Our results provide evidence for the existence of an unrecognized tumor immune escape involving cross-presentation of systemically circulating tumor antigens that may influence immunotherapy of cancer. Copyright © 2012 American Association for the Study of Liver Diseases.

  16. Nanobits - exchangable and customisable scanning probe tips

    DEFF Research Database (Denmark)

    Yildiz, Izzet

    Invention of atomic force microscopy (AFM) pioneered a novel aspect for the surface metrology concept. A range of scanning probe methods have been developed over the years based on different sorts of tip-surface interaction: electrical, optical, thermal, force. Reproducible and fast fabrication...... miniaturisation requires the scanning probes to adapt into finer geometries to provide higher lateral resolution. To meet these needs critical dimension AFM (CD-AFM) and deep trench AFM (DT-AFM) were invented, which use different types of AFM tips: high-aspect-ratio tips for DT-AFM and CD tips for CD...... replacement could greatly increase the efficiency and adaptability of a CD system. In this PhD study, NanoBits – nano-sized customisable and exchangeable scanning probe tips – were developed to meet the demands of current AFM applications. Two different methods were followed for the fabrication of Nano...

  17. Crack Tip Flipping under Mode I Tearing: Investigated by X-Ray Tomography

    DEFF Research Database (Denmark)

    Nielsen, Kim Lau; Gundlach, Carsten

    2017-01-01

    is on a crack tip where the flip is underway. Extensive growth of single edge cracks under mode I loading is achieved in a purpose build test set-up. Here, considering a 4 mm plate of normal strength / high strain hardening steel which has been found to display successive flipping of the slant crack face. While...... undergoing a shear band switch, such that the flipping mechanism is active, the plate tearing test is interrupted and the crack tip extracted for further investigation. The conducted X-ray tomography scans reveal the failure process ahead of the advancing crack tip to resemble the ductile slant crack growth...... at an angle to the primary tunneling slant crack. Eventually, these secondary crack fronts catch up on the primary slant crack front and overtake the growth to complete the shear band switch. Once the crack slants, an out-of-plane action occurs due to the loss of symmetry in the system. It is this out...

  18. The tipping point: A mathematical model for the profit-driven abandonment of restaurant tipping

    Science.gov (United States)

    Clifton, Sara M.; Herbers, Eileen; Chen, Jack; Abrams, Daniel M.

    2018-02-01

    The custom of voluntarily tipping for services rendered has gone in and out of fashion in America since its introduction in the 19th century. Restaurant owners that ban tipping in their establishments often claim that social justice drives their decisions, but we show that rational profit-maximization may also justify the decisions. Here, we propose a conceptual model of restaurant competition for staff and customers, and we show that there exists a critical conventional tip rate at which restaurant owners should eliminate tipping to maximize profits. Because the conventional tip rate has been increasing steadily for the last several decades, our model suggests that restaurant owners may abandon tipping en masse when that critical tip rate is reached.

  19. Tip-splitting instabilities in the channel Saffman-Taylor flow of constant viscosity elastic fluids

    International Nuclear Information System (INIS)

    Vlad, D. H.; Maher, J. V.

    2000-01-01

    Boger fluids are used to study viscous fingering growth in viscoelastic fluids in channel Hele-Shaw flow. We have found that the viscous finger growing in the Boger fluid is unstable to tip splitting at high velocities, in a regime where a Newtonian viscous finger is stable. No fracturelike instabilities were observed. We show that the viscoelastic normal stress differences arising in shear and extensional flow reach very high values at shear and extensional rates comparable to those achieved at the tip of the finger at the onset of tip splitting, and the fluid becomes highly anisotropic. The viscoelastic stress could affect the dynamics of the finger and induce the tip-splitting instability. (c) 2000 The American Physical Society

  20. Mathieu function solutions for photoacoustic waves in sinusoidal one-dimensional structures.

    Science.gov (United States)

    Wu, Binbin; Diebold, Gerald J

    2012-07-01

    The photoacoustic effect for a one-dimensional structure, the sound speed of which varies sinusoidally in space, is shown to be governed by an inhomogeneous Mathieu equation with the forcing term dependent on the spatial and temporal properties of the exciting optical radiation. New orthogonality relations, traveling wave Mathieu functions, and solutions to the inhomogeneous Mathieu equation are found, which are used to determine the character of photoacoustic waves in infinite and finite length phononic structures. Floquet solutions to the Mathieu equation give the positions of the band gaps, the damping of the acoustic waves within the band gaps, and the dispersion relation for photoacoustic waves. The solutions to the Mathieu equation give the photoacoustic response of the structure, show the space equivalent of subharmonic generation and acoustic confinement when waves are excited within band gaps.

  1. A feedback control system for vibration of magnetostrictive plate subjected to follower force using sinusoidal shear

    Directory of Open Access Journals (Sweden)

    A. Ghorbanpour Arani

    2016-03-01

    Full Text Available In this research, the vibrational behavior of magnetostrictive plate (MsP as a smart component is studied. The plate is subjected to an external follower force and a magnetic field in which the vibration response of MsP has been investigated for both loading combinations. The velocity feedback gain parameter is evaluated to study the effect of magnetic field which is generated by the coil. Sinusoidal shear deformation theory is utilized due to its accuracy of polynomial function with respect to other plate theories. Equations of motion are derived using Hamilton’s principle and solved by differential quadrature method (DQM considering general boundary conditions. The effects of aspect ratio, thickness ratio, follower force and velocity feedback gain are investigated on the frequency response of MsP. Results indicate that magneto-mechanical coupling in MsM helps to control vibrational behaviors of systems such as electro-hydraulic actuator, wireless linear Motors and sensors.

  2. Continuously varying skin potentials elicited by sinusoidally varying electric shock potentials

    Science.gov (United States)

    Senders, J. W.; Senders, V. L.; Tursky, B.

    1973-01-01

    An investigation was carried out to determine whether a form of quasi-linear systems analysis can be applied to electrodormal responses to yield new insights into the nature of the response mechanisms and their interrelationships. The response investigated was the electrodermal response (galvanic skin potential, GSP) as elicited by an electric shock stimulus applied to the skin. The response subsequent to this stimulation was examined and its characteristics measured. A series of experimental runs on three Ss was accomplished, using sinusoidal modulation envelopes of frequencies. Results showed that it was possible to drive the GSP and to achieve relatively high coherence between the driving frequency and the response itself. The analysis was limited to Fourier analysis of the response in order to determine the relative energies at the driving frequency and at successive harmonics of that driving frequency, and correlational analysis in order to determine the degree of linear relationship between the driving frequency and the driven response.

  3. Influence of muscle cooling on the viscoelastic response of the human ankle to sinusoidal displacements.

    Science.gov (United States)

    Price, R; Lehmann, J F

    1990-09-01

    The changes in passive mechanical muscle properties due to cooling of the calf in healthy human volunteers were investigated. The technique, using sinusoidal driving of the foot, permitted the separation of muscle stiffness response into its elastic and viscous components. Cooling the calf with ice for 30 minutes increases the rate of change of elastic stiffness with frequency, and it increases the frictional stiffness over a frequency range of 3 to 12Hz. Such cooling would produce an estimated 3% to 10% increase in total stiffness, on average, in a spastic person. This increase in stiffness would counteract reductions in total stiffness achieved during the application of cryotherapy to relieve spasticity. However, one could expect that for a clinically significant reduction of spasticity, the increase in passive stiffness of the muscle generated by cooling would be largely overshadowed by the decrease in reflex reactivity.

  4. Exponential sinusoidal model for predicting temperature inside underground wine cellars from a Spanish region

    Energy Technology Data Exchange (ETDEWEB)

    Mazarron, Fernando R.; Canas, Ignacio [Departamento de Construccion y Vias Rurales, Escuela Tecnica Superior de Ingenieros Agronomos, Universidad Politecnica de Madrid, Avda. Complutense s/n, 28040 Madrid (Spain)

    2008-07-01

    This article develops a mathematical model for determining the annual cycle of air temperature inside traditional underground wine cellars in the Spanish region of ''Ribera del Duero'', known because of the quality of its wines. It modifies the sinusoidal analytical model for soil temperature calculation. Results obtained when contrasting the proposed model with experimental data of three subterranean wine cellars for 2 years are satisfactory. The RMSE is below 1 C and the index of agreement is above 0.96 for the three cellars. When using the average of experimental data corresponding to the 2 years' time, results improve noticeably: the RMSE decreases by more than 30% and the mean d reaches 0.99. This model should be a useful tool for designing underground wine cellars making the most of soil energy advantages. (author)

  5. Accurate estimation of the illumination pattern's orientation and wavelength in sinusoidal structured illumination microscopy.

    Science.gov (United States)

    Lahrberg, Marcel; Singh, Mandeep; Khare, Kedar; Ahluwalia, Balpreet Singh

    2018-02-10

    Structured illumination microscopy is able to improve the spatial resolution of wide-field fluorescence imaging by applying sinusoidal stripe pattern illumination to the sample. The corresponding computational image reconstruction requires precise knowledge of the pattern's parameters, which are its phase (ϕ) and wave vector (p). Here, a computationally inexpensive method for estimation of p from the raw data is proposed and illustrated with simulations. The method estimates p through a selective discrete Fourier transform at tunable subpixel precision. This results in an accurate p estimation for all the illumination patterns and subsequently improves the superresolution image recovery by a factor of 10 around sharp edges as compared to an integer pixel approach. The technique as presented here is of major interest to the large variety of custom-build systems that are used. The feasibility of the presented method is proven in comparison with published data.

  6. Engraftment and reconstitution of hematopoiesis is dependent on VEGFR2-mediated regeneration of sinusoidal endothelial cells.

    Science.gov (United States)

    Hooper, Andrea T; Butler, Jason M; Nolan, Daniel J; Kranz, Andrea; Iida, Kaoruko; Kobayashi, Mariko; Kopp, Hans-Georg; Shido, Koji; Petit, Isabelle; Yanger, Kilangsungla; James, Daylon; Witte, Larry; Zhu, Zhenping; Wu, Yan; Pytowski, Bronislaw; Rosenwaks, Zev; Mittal, Vivek; Sato, Thomas N; Rafii, Shahin

    2009-03-06

    Myelosuppression damages the bone marrow (BM) vascular niche, but it is unclear how regeneration of bone marrow vessels contributes to engraftment of transplanted hematopoietic stem and progenitor cells (HSPCs) and restoration of hematopoiesis. We found that chemotherapy and sublethal irradiation induced minor regression of BM sinusoidal endothelial cells (SECs), while lethal irradiation induced severe regression of SECs and required BM transplantation (BMT) for regeneration. Within the BM, VEGFR2 expression specifically demarcated a continuous network of arterioles and SECs, with arterioles uniquely expressing Sca1 and SECs uniquely expressing VEGFR3. Conditional deletion of VEGFR2 in adult mice blocked regeneration of SECs in sublethally irradiated animals and prevented hematopoietic reconstitution. Similarly, inhibition of VEGFR2 signaling in lethally irradiated wild-type mice rescued with BMT severely impaired SEC reconstruction and prevented engraftment and reconstitution of HSPCs. Therefore, regeneration of SECs via VEGFR2 signaling is essential for engraftment of HSPCs and restoration of hematopoiesis.

  7. Compact ASD Topologies for Single-Phase Integrated Motor Drives with Sinusoidal Input Current

    DEFF Research Database (Denmark)

    Klumpner, Christian; Blaabjerg, Frede; Thoegersen, Paul

    2005-01-01

    A standard configuration of an Adjustable Speed Drive (ASD) consists of two separate units: an AC motor, which runs with fixed speed when it is supplied from a constant frequency grid voltage and a frequency converter, which is used to provide the motor with variable voltage-variable frequency......-density integration of the converter caused by the large size of the passive components (electrolytic capacitors and iron chokes) and vibration of the converter enclosure. This paper analyzes the implementation aspects for obtaining a compact and cost effective single-phase ASD with sinusoidal input current...... for high frequency operation, higher core losses will occur, but outside the converter enclosure. The advantages are: the reduction of the number of active semiconductor devices, the reduction of the ASD size and the better integration potential....

  8. Performance of pyrolyzed photoresist carbon films in a microchip capillary electrophoresis device with sinusoidal voltammetric detection.

    Science.gov (United States)

    Hebert, Nicole E; Snyder, Brian; McCreery, Richard L; Kuhr, Werner G; Brazill, Sara A

    2003-08-15

    Pyrolyzed photoresist films (PPF) are introduced as planar carbon electrodes in a PDMS-quartz hybrid microchip device. The utility of PPF in electroanalytical applications is demonstrated by the separation and detection of various neurotransmitters. PPF is found to form a stable, low-capacitance, durable layer on quartz, which can then be used in conjunction with a microchip capillary electrophoretic device. Sinusoidal voltammetric detection at PPF electrodes is shown to be very sensitive, with a detection limit (S/N = 3) of 100 nM for dopamine, corresponding to a mass detection limit (S/N = 3) of 2 amol. The selectivity of analysis in the frequency domain is demonstrated by isolating each individual signal in a pair of analytes that are chromatographically unresolved. Effectively decoupling the electrophoresis and electrochemical systems allows the electrodes to be placed just inside the separation channel, which results in efficient separations (80 000-100 000 plates/m).

  9. A "Brick Mass Spectrometer" Driven by a Sinusoidal Frequency Scanning Technique.

    Science.gov (United States)

    Jiang, Ting; Zhang, Hongjia; Tang, Yang; Zhai, Yanbing; Xu, Wei; Xu, Hualei; Zhao, Xinying; Li, Dayu; Xu, Wei

    2017-05-16

    In this work, a "brick" size miniature mass spectrometer (28 cm × 21 cm × 16 cm) was developed and characterized, which was enabled by the development of a new frequency scanning technique. Different from the conventional voltage scanning method or the digital waveforms used on a digital ion trap, a sinusoidal frequency scanning technique was developed to drive the linear ion trap of the brick mass spectrometer (BMS). Both an in-vacuum plasma ionization source and an electrospray ionization source were coupled with this BMS for the analyses of volatile and nonvolatile samples. Stability diagram, sensitivity, mass resolution, and mass range of the BMS were explored. This new frequency scanning technique could not only reduce the size and power consumption of a miniature mass spectrometer but also improve its analytical performances, especially in terms of mass range and resolution. Analogous to the development of cell phones, this BMS would be an important step from "brick" mass spectrometer to "cell" mass spectrometer.

  10. Real-time detection of musical onsets with linear prediction and sinusoidal modeling

    Science.gov (United States)

    Glover, John; Lazzarini, Victor; Timoney, Joseph

    2011-12-01

    Real-time musical note onset detection plays a vital role in many audio analysis processes, such as score following, beat detection and various sound synthesis by analysis methods. This article provides a review of some of the most commonly used techniques for real-time onset detection. We suggest ways to improve these techniques by incorporating linear prediction as well as presenting a novel algorithm for real-time onset detection using sinusoidal modelling. We provide comprehensive results for both the detection accuracy and the computational performance of all of the described techniques, evaluated using Modal, our new open source library for musical onset detection, which comes with a free database of samples with hand-labelled note onsets.

  11. Sensitivity of echo enabled harmonic generation to sinusoidal electron beam energy structure

    Directory of Open Access Journals (Sweden)

    E. Hemsing

    2017-06-01

    Full Text Available We analytically examine the bunching factor spectrum of a relativistic electron beam with sinusoidal energy structure that then undergoes an echo-enabled harmonic generation (EEHG transformation to produce high harmonics. The performance is found to be described primarily by a simple scaling parameter. The dependence of the bunching amplitude on fluctuations of critical parameters is derived analytically, and compared with simulations. Where applicable, EEHG is also compared with high gain harmonic generation (HGHG and we find that EEHG is generally less sensitive to several types of energy structure. In the presence of intermediate frequency modulations like those produced by the microbunching instability, EEHG has a substantially narrower intrinsic bunching pedestal.

  12. Dynamic Buckling of Embedded Laminated Nanocomposite Plates Based on Sinusoidal Shear Deformation Theory

    Directory of Open Access Journals (Sweden)

    Mohammd Sharif Zarei

    2016-12-01

    Full Text Available In this study, the dynamic buckling of the embedded laminated nanocomposite plates is investigated. The plates are reinforced with the single-walled carbon nanotubes (SWCNTs, and the Mori-Tanaka model is applied to obtain the equivalent material properties of them. Based on the sinusoidal shear deformation theory (SSDT, the motion equations are derived using the energy method and Hamilton's principle. The Navier’s method is used in conjunction with the Bolotin's method for obtaining the dynamic instability region (DIR of the structure. The effects of different parameters such as the volume percentage of SWCNTs, the number and orientation angle of the layers, the elastic medium, and the geometrical parameters of the plates are shown on DIR of the structure. Results indicate that by increasing the volume percentage of SWCNTs the resonance frequency increases, and DIR shifts to right. Moreover, it is found that the present results are in good agreement with the previous researches.

  13. Optimal sinusoidal modelling of gear mesh vibration signals for gear diagnosis and prognosis

    Science.gov (United States)

    Man, Zhihong; Wang, Wenyi; Khoo, Suiyang; Yin, Juliang

    2012-11-01

    In this paper, the synchronous signal average of gear mesh vibration signals is modelled with the multiple modulated sinusoidal representations. The signal model parameters are optimised against the measured signal averages by using the batch learning of the least squares technique. With the optimal signal model, all components of a gear mesh vibration signal, including the amplitude modulations, the phase modulations and the impulse vibration component induced by gear tooth cracking, are identified and analysed with insight of the gear tooth crack development and propagation. In particular, the energy distribution of the impulse vibration signal, extracted from the optimal signal model, provides sufficient information for monitoring and diagnosing the evolution of the tooth cracking process, leading to the prognosis of gear tooth cracking. The new methodologies for gear mesh signal modelling and the diagnosis of the gear tooth fault development and propagation are validated with a set of rig test data, which has shown excellent performance.

  14. Neural adaptive control for vibration suppression in composite fin-tip of aircraft.

    Science.gov (United States)

    Suresh, S; Kannan, N; Sundararajan, N; Saratchandran, P

    2008-06-01

    In this paper, we present a neural adaptive control scheme for active vibration suppression of a composite aircraft fin tip. The mathematical model of a composite aircraft fin tip is derived using the finite element approach. The finite element model is updated experimentally to reflect the natural frequencies and mode shapes very accurately. Piezo-electric actuators and sensors are placed at optimal locations such that the vibration suppression is a maximum. Model-reference direct adaptive neural network control scheme is proposed to force the vibration level within the minimum acceptable limit. In this scheme, Gaussian neural network with linear filters is used to approximate the inverse dynamics of the system and the parameters of the neural controller are estimated using Lyapunov based update law. In order to reduce the computational burden, which is critical for real-time applications, the number of hidden neurons is also estimated in the proposed scheme. The global asymptotic stability of the overall system is ensured using the principles of Lyapunov approach. Simulation studies are carried-out using sinusoidal force functions of varying frequency. Experimental results show that the proposed neural adaptive control scheme is capable of providing significant vibration suppression in the multiple bending modes of interest. The performance of the proposed scheme is better than the H(infinity) control scheme.

  15. Numerical study on Wells turbine with penetrating blade tip treatments for wave energy conversion

    Directory of Open Access Journals (Sweden)

    Ying Cui

    2016-09-01

    Full Text Available In order to optimize the performance of a Wells turbine with fixed guide vanes, the designs of an end plate and a ring on the tip of the turbine rotor are proposed as penetrating blade tip treatments. In this study, numerical investigations are made using computational fluid dynamics (CFD-based ANSYS Fluent software, and validated by corresponding experimental data. The flow fields are analyzed and non-dimensional coefficients CA, CT and η are calculated under steady-state conditions. Numerical results show that the stalling phenomenon on a ring-type Wells turbine occurs at a flow coefficient of ϕ = 0.36, and its peak efficiency can reach 0.54, which is 16% higher than that of an unmodified turbine and 9% higher than in the case of an endplate-type turbine. In addition, quasi-steady analysis is used to calculate the mean efficiency and output work of a wave cycle under sinusoidal flow conditions. As a result, it has been found that the ring-type turbine is superior to other types of Wells turbines.

  16. Crack Tip Mechanics in Distortion Gradient Plasticity

    DEFF Research Database (Denmark)

    Fuentes-Alonso, Sandra; Martínez Pañeda, Emilio

    2017-01-01

    The important role of geometrically necessary dislocations in structural integrity assessment has encouraged an extensive use of strain gradient plasticity theories to characterize the behavior at the small scales involved in crack tip deformation. However, despite the popularity of Distortion...... Gradient Plasticity (DGP), the influence on crack tip mechanics of DGP's distinguishing features that entail superior modelling capabilities has not been investigated yet. In this work crack tip fields are thoroughly examined by implementing the higher order theory of DGP in an implicit finite element...

  17. CFD analysis of cloud cavitation on three tip-modified propellers with systematically varied tip geometry

    Science.gov (United States)

    Shin, K. W.; Andersen, P.

    2015-12-01

    The blade tip loading is often reduced as an effort to restrain sheet and tip vortex cavitation in the design of marine propellers. This CFD analysis demonstrates that an excessive reduction of the tip loading can cause cloud cavitation responsible for much of noise and surface erosion. Detached eddy simulations (DES) are made for cavitating flows on three tip- modified propellers, of which one is a reference propeller having an experimental result from a cavitation tunnel test with a hull model, and the other two are modified from the reference propeller by altering the blade tip loading. DES results have been validated against the experiment in terms of sheet and cloud cavitation. In DES, non-uniform hull wake is modelled by using the inlet flow and momentum sources instead of including a hull model. A 4-bladed Kappel propeller with a smooth tip bending towards the suction side is used as the reference propeller. For the reference propeller, sheet cavitation extends over a whole chord length in the hull wake peak. As the blade gets out of the wake peak, the rear part of sheet cavity is detached in a form of cloud cavitation. For the reference propeller, the tip pitch reduction from the maximum is about 35%. When decreasing the tip pitch reduction to 10%, tip vortex cavitation is formed and cloud cavitation is significantly weakened. When increasing the tip pitch reduction to 60%, sheet cavitation slightly moves to inner radii and cloud cavitation grows larger.

  18. A novel tracking tool for the analysis of plant-root tip movements

    International Nuclear Information System (INIS)

    Russino, A; Ascrizzi, A; Popova, L; Tonazzini, A; Mancuso, S; Mazzolai, B

    2013-01-01

    The growth process of roots consists of many activities, such as exploring the soil volume, mining minerals, avoiding obstacles and taking up water to fulfil the plant's primary functions, that are performed differently, depending on environmental conditions. Root movements are strictly related to a root decision strategy, which helps plants to survive under stressful conditions by optimizing energy consumption. In this work, we present a novel image-analysis tool to study the kinematics of the root tip (apex), named analyser for root tip tracks (ARTT). The software implementation combines a segmentation algorithm with additional software imaging filters in order to realize a 2D tip detection. The resulting paths, or tracks, arise from the sampled tip positions through the acquired images during the growth. ARTT allows work with no markers and deals autonomously with new emerging root tips, as well as handling a massive number of data relying on minimum user interaction. Consequently, ARTT can be used for a wide range of applications and for the study of kinematics in different plant species. In particular, the study of the root growth and behaviour could lead to the definition of novel principles for the penetration and/or control paradigms for soil exploration and monitoring tasks. The software capabilities were demonstrated by experimental trials performed with Zea mays and Oryza sativa. (paper)

  19. Continuous and discontinuous fatigue crack growth of irradiated ultrahigh molecular mass polyethylene in saline solution at 37oC

    International Nuclear Information System (INIS)

    Zeng, Z.P.; Buggy, M.; Griffin, J.; Little, E.G.

    1992-01-01

    To provide data for prosthesis design, the fatigue crack growth resistance of irradiated ultrahigh molecular mass polyethylene (UHMMPE) in saline solution at 37 o C was determined from tests performed on compact tension specimens, comparable in size to the components in knee prostheses. The specimens were cyclically loaded by using a sinusoidal wave form at 1 Hz with a minimum-to-maximum load ratio of 0.1. Scanning electron microscopic fractography was used to examine the fracture surfaces. At higher stress levels, the Paris's Law was used to analyse the data, and a striation pattern with each striation corresponding to multi-cycles was observed. At lower stress levels, discontinuous fatigue crack growth was found, a phenomenon which dominated the fatigue life of the material and had not been reported previously in this material. A craze zone ahead of the crack tip was observed, which formed the discontinuous crack growth band with a length relevant to the Dugdale plastic zone length. (author)

  20. Continuous and discontinuous fatigue crack growth of irradiated ultrahigh molecular mass polyethylene in saline solution at 37 sup o C

    Energy Technology Data Exchange (ETDEWEB)

    Zeng, Z.P.; Buggy, M.; Griffin, J.; Little, E.G. (Limerick Univ. (Ireland). Dept. of Mechanical and Production Engineering)

    1992-07-01

    To provide data for prosthesis design, the fatigue crack growth resistance of irradiated ultrahigh molecular mass polyethylene (UHMMPE) in saline solution at 37{sup o}C was determined from tests performed on compact tension specimens, comparable in size to the components in knee prostheses. The specimens were cyclically loaded by using a sinusoidal wave form at 1 Hz with a minimum-to-maximum load ratio of 0.1. Scanning electron microscopic fractography was used to examine the fracture surfaces. At higher stress levels, the Paris's Law was used to analyse the data, and a striation pattern with each striation corresponding to multi-cycles was observed. At lower stress levels, discontinuous fatigue crack growth was found, a phenomenon which dominated the fatigue life of the material and had not been reported previously in this material. A craze zone ahead of the crack tip was observed, which formed the discontinuous crack growth band with a length relevant to the Dugdale plastic zone length. (author).

  1. Smooth School Transitions: Tips for Military Families

    Science.gov (United States)

    ... Life Listen Text Size Email Print Share Smooth School Transitions: Tips for Military Families Page Content Article ... Internet is a great resource for this. District & School Web sites Parents and children can visit the ...

  2. Helping Your Child: Tips for Parents

    Science.gov (United States)

    ... inactive computer and video games, or listening to music on hand-held devices while sitting down. Tips ... habits or weight. Remember, you play the biggest role in your children's lives. You can help your ...

  3. Tips for Teens with Diabetes: About Diabetes

    Science.gov (United States)

    National Diabetes Education Program (NDEP), 2010

    2010-01-01

    Diabetes is a serious disease. It means that one's blood glucose, also called blood sugar, is too high. Having too much glucose in a person's blood is not healthy. This paper offers tips for managing diabetes.

  4. Winter Safety Tips for Older Adults

    Science.gov (United States)

    Winter Safety Tips for Older Adults Expert Information from Healthcare Professionals Who Specialize in the Care of ... thick clothing. Think about getting your thermals! –Essential winter wears: hats, gloves or preferably mittens, winter coat, ...

  5. Essential Outdoor Sun Safety Tips for Winter

    Science.gov (United States)

    ... Vitamin D Essential Outdoor Sun Safety Tips for Winter Winter sports enthusiasts are at increased risk for overexposure ... associated with sun exposure. "It's easy to associate winter with frostbite and windburn, but most people are ...

  6. Can't sleep? Try these tips

    Science.gov (United States)

    ... medlineplus.gov/ency/patientinstructions/000853.htm Can't sleep? Try these tips To use the sharing features ... time. But if it happens often, lack of sleep can affect your health and make it hard ...

  7. Sleep Tips: 7 Steps to Better Sleep

    Science.gov (United States)

    ... turn every night. Consider simple tips for better sleep, from setting a sleep schedule to including physical activity in your daily ... factors that can interfere with a good night's sleep — from work stress and family responsibilities to unexpected ...

  8. Impetigo: Tips for Treatment and Prevention

    Science.gov (United States)

    ... DO Videos Contact Close ‹ Back to Healthy Living Impetigo: Tips for Treatment and Prevention The symptoms of ... to other parts of their bodies. Causes of Impetigo Impetigo usually affects preschool and school-aged children, ...

  9. Next Stop Adulthood: Tips for Parents

    Science.gov (United States)

    ... Email Print Share Next Stop Adulthood: Tips For Parents Page Content Article Body Becoming a young adult is exciting, difficult, and scary for both parents and teens. It is a time of increasing ...

  10. 6 Tips: IBS and Complementary Health Practices

    Science.gov (United States)

    ... health practice for IBS, here are 6 tips: Hypnotherapy (hypnosis). This practice involves the power of suggestion by ... IBS. According to reviews of the scientific literature, hypnotherapy may be a helpful treatment for managing IBS ...

  11. Tips to Manage Anxiety and Stress

    Science.gov (United States)

    ... 2018 Conference Snapshot Tips to Manage Anxiety and Stress When you're feeling anxious or stressed, the ... Subscribe to ADAA Triumph: Free Monthly E-News Stress Relief Kits Feeling stressed? Get an ADAA stress ...

  12. Research on a new magnetic-field-modulated brushless double-rotor machine with sinusoidal-permeance modulating ring

    Science.gov (United States)

    Zheng, Ping; Liu, Jiaqi; Bai, Jingang; Song, Zhiyi; Liu, Yong

    2017-05-01

    The magnetic-field-modulated brushless double-rotor machine (MFM-BDRM), composed of a stator, a modulating ring rotor, and a PM rotor, is a kind of power-split device for hybrid electric vehicles (HEVs). In this paper, a new MFM-BDRM with sinusoidal-permeance modulating ring named Sinusoidal-Permeance-Modulating-Ring Brushless Double-Rotor Machine (SPMR-BDRM) is proposed to solve the problem of poor mechanical strength and large iron loss. The structure and the operating principle of the MFM-BDRM are introduced. The design principle of the sinusoidal-permeance modulating ring is analyzed and derived. The main idea of that is to minimize the harmonic permeance of air gap, thereby the harmonic magnetic fields can be restrained. There are comparisons between a MFM-BDRM with sinusoidal-permeance modulating ring and a same size MFM-BDRM with traditional modulating ring, including magnetic field distributions and electromagnetic performances. Most importantly, the iron losses are compared under six different conditions. The result indicates that the harmonic magnetic fields in the air gap are restrained; the electromagnetic torque and power factor are almost the same with same armature current; the torque ripples of the modulating ring rotor and the PM rotor are reduced; the stator loss is reduced by 13% at least and the PM loss is reduced by 20% at least compared with the same size traditional MFM-BDRM under the same operating conditions.

  13. Generation of sinusoidal fringes with a holographic phase grating and a phase-only spatial light modulator

    International Nuclear Information System (INIS)

    Berberova, Natalia; Stoykova, Elena; Sainov, Ventseslav

    2012-01-01

    A variety of pattern projection methods for the three-dimensional capture of objects is based on the generation of purely sinusoidal fringes. This is not an easy task, especially when a portable non-interferometric system for outdoor usage is required. The use of phase gratings with coherent illumination as a possible solution has the advantage of providing good stability and a large measurement volume. In this work, we analyze the quality of fringes projected with two sinusoidal phase gratings. The first grating is recorded on a silver-halide holographic plate by means of a Michelson interferometer. The spatial resolution of the silver-halide material used is greater than 6000 lines per millimeter, and the recorded grating is practically analogous to a smooth variation of the phase profile. The second grating is formed as a sinusoidal phase variation on a liquid crystal-on-silicon phase-only reflective display with a resolution of 1920×1080 pixels, a pixel pitch of 8 μm and 256 phase levels. The frequency content of the fringes projected with both gratings is analyzed and compared on the basis of the calculated Fresnel diffraction pattern, taking into account that the sinusoidal phase distribution in the case of a spatial light modulator is both sampled and quantized. Experimental fringe patterns projected using both gratings are also provided.

  14. Research on a new magnetic-field-modulated brushless double-rotor machine with sinusoidal-permeance modulating ring

    Directory of Open Access Journals (Sweden)

    Ping Zheng

    2017-05-01

    Full Text Available The magnetic-field-modulated brushless double-rotor machine (MFM-BDRM, composed of a stator, a modulating ring rotor, and a PM rotor, is a kind of power-split device for hybrid electric vehicles (HEVs. In this paper, a new MFM-BDRM with sinusoidal-permeance modulating ring named Sinusoidal-Permeance-Modulating-Ring Brushless Double-Rotor Machine (SPMR-BDRM is proposed to solve the problem of poor mechanical strength and large iron loss. The structure and the operating principle of the MFM-BDRM are introduced. The design principle of the sinusoidal-permeance modulating ring is analyzed and derived. The main idea of that is to minimize the harmonic permeance of air gap, thereby the harmonic magnetic fields can be restrained. There are comparisons between a MFM-BDRM with sinusoidal-permeance modulating ring and a same size MFM-BDRM with traditional modulating ring, including magnetic field distributions and electromagnetic performances. Most importantly, the iron losses are compared under six different conditions. The result indicates that the harmonic magnetic fields in the air gap are restrained; the electromagnetic torque and power factor are almost the same with same armature current; the torque ripples of the modulating ring rotor and the PM rotor are reduced; the stator loss is reduced by 13% at least and the PM loss is reduced by 20% at least compared with the same size traditional MFM-BDRM under the same operating conditions.

  15. Using composite sinusoidal patterns in structured-illumination reflectance imaging (SIRI) for enhanced detection of defects in food

    Science.gov (United States)

    This study presented a first exploration of using composite sinusoidal patterns that integrated two and three spatial frequencies of interest, in structured-illumination reflectance imaging (SIRI) for enhanced detection of defects in food (e.g., bruises in apples). Three methods based on Fourier tra...

  16. Tip velocity tracking control for elastic manipulators

    Science.gov (United States)

    Sever, Manfred Dieter Martin

    A unique approach to tip velocity control of an elastic robotic manipulator is presented. This method has potential application in teleoperation control and in applications where the trajectory is generated in real-time. Control is effected by reducing the tip velocity tracking error between the desired tip velocity and the measured tip velocity. Thus, in teleoperation, the concept of dead reckoning is used, so that while the manipulator's desired tip velocity is specified, the goal is for the tip to follow a path, leading toward a desired terminal position. This is done by concentrating the controller's effort on the manipulator tip while allowing the manipulator's links to deform., The controller utilizes a gain scheduling scheme to arrive at an appropriate feedback law. The control algorithm is implemented using a parallel-processing scheme on a multiprocessor system which consists of INMOS TransputersRTM . Experimental results are obtained using Radius, the Space Robotics Laboratory Facility at the University of Toronto Institute for Aerospace Studies. Radius was designed to serve specifically as a test-bed for the development and evaluation of control methods for elastic manipulators. For the present work Radius is configured as a two-link manipulator with both links structurally flexible. One of the trajectories used for the simulations and experiment is a square, which is quite difficult for an elastic manipulator to execute. This box trajectory is more demanding than trajectories typically executed by Canadarm and so link elasticity becomes an important consideration. The effect of elasticity is demonstrated using an independent joint PD controller. In simulation, excellent tip velocity tracking was achieved using the proposed controller. In the experiment, reasonable accuracy in following the desired tip path was attained, however, disturbances, mainly a result of unmodeled joint dynamics, caused degraded performance. The controller may be improved by

  17. Full tip imaging in atom probe tomography

    Energy Technology Data Exchange (ETDEWEB)

    Du, Sichao [School of Physics, The University of Sydney, NSW 2006 (Australia); Burgess, Timothy [Department of Electronic Materials Engineering, Research School of Physics and Engineering, The Australian National University, Canberra, ACT 0200 (Australia); Tjing Loi, Shyeh [Australian Centre for Microscopy and Microanalysis, The University of Sydney, NSW 2006 (Australia); Gault, Baptiste [Australian Centre for Microscopy and Microanalysis, The University of Sydney, NSW 2006 (Australia); School of Aerospace, Mechanical and Mechatronic Engineering, The University of Sydney, NSW 2006 (Australia); Department of Materials Science and Engineering, McMaster University, 1280 Main St W, Hamilton, ON, Canada L8S 4L8 (Canada); Gao, Qiang [Department of Electronic Materials Engineering, Research School of Physics and Engineering, The Australian National University, Canberra, ACT 0200 (Australia); Bao, Peite; Li, Li [School of Physics, The University of Sydney, NSW 2006 (Australia); Cui, Xiangyuan; Kong Yeoh, Wai [Australian Centre for Microscopy and Microanalysis, The University of Sydney, NSW 2006 (Australia); Hoe Tan, Hark; Jagadish, Chennupati [Department of Electronic Materials Engineering, Research School of Physics and Engineering, The Australian National University, Canberra, ACT 0200 (Australia); Ringer, Simon P. [Australian Centre for Microscopy and Microanalysis, The University of Sydney, NSW 2006 (Australia); School of Aerospace, Mechanical and Mechatronic Engineering, The University of Sydney, NSW 2006 (Australia); Zheng, Rongkun, E-mail: rongkun.zheng@sydney.edu.au [School of Physics, The University of Sydney, NSW 2006 (Australia)

    2013-01-15

    Atom probe tomography (APT) is capable of simultaneously revealing the chemical identities and three dimensional positions of individual atoms within a needle-shaped specimen, but suffers from a limited field-of-view (FOV), i.e., only the core of the specimen is effectively detected. Therefore, the capacity to analyze the full tip is crucial and much desired in cases that the shell of the specimen is also the region of interest. In this paper, we demonstrate that, in the analysis of III-V nanowires epitaxially grown from a substrate, the presence of the flat substrate positioned only micrometers away from the analyzed tip apex alters the field distribution and ion trajectories, which provides extra image compression that allows for the analysis of the entire specimen. An array of experimental results, including field desorption maps, elemental distributions, and crystallographic features clearly demonstrate the fact that the whole tip has been imaged, which is confirmed by electrostatic simulations. -- Highlights: Black-Right-Pointing-Pointer The full tip has been imaged by atom probe tomography. Black-Right-Pointing-Pointer The conductive substrate close to specimen tip introduces extra image compression. Black-Right-Pointing-Pointer The apex of the tip is far from a hemispherical shape. Black-Right-Pointing-Pointer This work demonstrates a way to increase the FOV of APT.

  18. THE SINUSOIDAL EFFLUX OF DIBROMOSULFOPHTHALEIN FROM RAT-LIVER IS STIMULATED BY ALBUMIN, LIGANDIN AND FATTY-ACID-BINDING PROTEIN BUT NOT BY OTHER DIBROMOSULFOPHTHALEIN BINDING-PROTEINS

    NARCIS (Netherlands)

    NIJSSEN, HMJ; PIJNING, T; PROOST, JH; MEIJER, DKF; GROOTHUIS, GMM

    Organic anions can be excreted from the liver into the bile or back into the general circulation (sinusoidal efflux). It has previously been shown that the net sinusoidal efflux rate of dibromosulfophthalein from the perfused liver into the perfusate is the result of actual efflux from and reuptake

  19. A scanning microscopy technique based on capacitive coupling with a field-effect transistor integrated with the tip.

    Science.gov (United States)

    Shin, Kumjae; Kang, Dae sil; Lee, Sang hoon; Moon, Wonkyu

    2015-12-01

    We propose a method for measuring the capacitance of a thin layer using a Tip-on-Gate of Field-Effect Transistor (ToGoFET) probe. A ToGoFET probe with a metal-oxide-semiconductor field-effect transistor (MOSFET) with an ion-implant channel was embedded at the end of a cantilever and a Pt tip was fabricated using micro-machining. The ToGoFET probe was used to detect an alternating electric field at the dielectric surface. A dielectric buried metal sample was prepared; a sinusoidal input signal was applied to the buried metal lines; and the ToGoFET probe detected the electric field at the tip via the dielectric. The AC signal detected by the ToGoFET probe was demodulated by a simple AC-to-DC converter. Experimentally, it was shown that an electric field could be measured at the surface of the dielectric layer above a buried metal line. This promising result shows that it is possible to measure the surface local capacitance. Copyright © 2015 Elsevier B.V. All rights reserved.

  20. GPR182 is a novel marker for sinusoidal endothelial differentiation with distinct GPCR signaling activity in vitro.

    Science.gov (United States)

    Schmid, Christian David; Schledzewski, Kai; Mogler, Carolin; Waldburger, Nina; Kalna, Viktoria; Marx, Alexander; Randi, Anna Maria; Géraud, Cyrill; Goerdt, Sergij; Koch, Philipp-Sebastian

    2018-02-01

    Endothelial cells (EC) along the vascular tree exhibit organ-specific angiodiversity. Compared to most other ECs, liver sinusoidal endothelial cells (LSEC) that constitute the organ-specific microvasculature of the liver are morphologically and functionally unique. Previously, we showed that transcription factor Gata4 acts as a master regulator controlling LSEC differentiation. Upon analysis of the molecular signature of LSEC, we identified GPR182 as a potential LSEC-specific orphan G-protein coupled receptor (GPCR). Here, we demonstrate that GPR182 is expressed by LSEC and by EC with sinusoidal differentiation in spleen, lymph node and bone marrow in healthy human tissues. In a tissue microarray analysis of human hepatocellular carcinoma (HCC) samples, endothelial GPR182 expression was significantly reduced in tumor samples compared to peritumoral liver tissue samples (p = 0.0105). Loss of endothelial GPR182 expression was also seen in fibrotic and cirrhotic liver tissues. In vitro, GPR182 differentially regulated canonical GPCR signaling pathways as shown using reporter luciferase assays in HEK293T cells. Whereas ERK and RhoA signaling were inhibited, CREB and Calcium signaling were activated by ectopic GPR182 overexpression. Our data demonstrate that GPR182 is an endothelial subtype-specific marker for human sinusoidal EC of the liver, spleen, lymph node and bone marrow. In addition, we provide evidence for GPR182-dependent downstream signaling via ERK and SRF pathways that may be involved in regulating endothelial subtype-specific sinusoidal differentiation and sinusoidal functions such as permeability. Copyright © 2018 The Author(s). Published by Elsevier Inc. All rights reserved.

  1. Nonlocal response functions for predicting shear flow of strongly inhomogeneous fluids. II. Sinusoidally driven shear and multisinusoidal inhomogeneity.

    Science.gov (United States)

    Dalton, Benjamin A; Glavatskiy, Kirill S; Daivis, Peter J; Todd, B D

    2015-07-01

    We use molecular-dynamics computer simulations to investigate the density, strain-rate, and shear-pressure responses of a simple model atomic fluid to transverse and longitudinal external forces. We have previously introduced a response function formalism for describing the density, strain-rate, and shear-pressure profiles in an atomic fluid when it is perturbed by a combination of longitudinal and transverse external forces that are independent of time and have a simple sinusoidal spatial variation. In this paper, we extend the application of the previously introduced formalism to consider the case of a longitudinal force composed of multiple sinusoidal components in combination with a single-component sinusoidal transverse force. We find that additional harmonics are excited in the density, strain-rate, and shear-pressure profiles due to couplings between the force components. By analyzing the density, strain-rate, and shear-pressure profiles in Fourier space, we are able to evaluate the Fourier coefficients of the response functions, which now have additional components describing the coupling relationships. Having evaluated the Fourier coefficients of the response functions, we are then able to accurately predict the density, velocity, and shear-pressure profiles for fluids that are under the influence of a longitudinal force composed of two or three sinusoidal components combined with a single-component sinusoidal transverse force. We also find that in the case of a multisinusoidal longitudinal force, it is sufficient to include only pairwise couplings between different longitudinal force components. This means that it is unnecessary to include couplings between three or more force components in the case of a longitudinal force composed of many Fourier components, and this paves the way for a highly accurate but tractable treatment of nonlocal transport phenomena in fluids with density and strain-rate inhomogeneities on the molecular length scale.

  2. Astronomical component estimation (ACE v.1) by time-variant sinusoidal modeling

    Science.gov (United States)

    Sinnesael, Matthias; Zivanovic, Miroslav; De Vleeschouwer, David; Claeys, Philippe; Schoukens, Johan

    2016-09-01

    Accurately deciphering periodic variations in paleoclimate proxy signals is essential for cyclostratigraphy. Classical spectral analysis often relies on methods based on (fast) Fourier transformation. This technique has no unique solution separating variations in amplitude and frequency. This characteristic can make it difficult to correctly interpret a proxy's power spectrum or to accurately evaluate simultaneous changes in amplitude and frequency in evolutionary analyses. This drawback is circumvented by using a polynomial approach to estimate instantaneous amplitude and frequency in orbital components. This approach was proven useful to characterize audio signals (music and speech), which are non-stationary in nature. Paleoclimate proxy signals and audio signals share similar dynamics; the only difference is the frequency relationship between the different components. A harmonic-frequency relationship exists in audio signals, whereas this relation is non-harmonic in paleoclimate signals. However, this difference is irrelevant for the problem of separating simultaneous changes in amplitude and frequency. Using an approach with overlapping analysis frames, the model (Astronomical Component Estimation, version 1: ACE v.1) captures time variations of an orbital component by modulating a stationary sinusoid centered at its mean frequency, with a single polynomial. Hence, the parameters that determine the model are the mean frequency of the orbital component and the polynomial coefficients. The first parameter depends on geologic interpretations, whereas the latter are estimated by means of linear least-squares. As output, the model provides the orbital component waveform, either in the depth or time domain. Uncertainty analyses of the model estimates are performed using Monte Carlo simulations. Furthermore, it allows for a unique decomposition of the signal into its instantaneous amplitude and frequency. Frequency modulation patterns reconstruct changes in

  3. Neuronal Oscillations with Non-sinusoidal Morphology Produce Spurious Phase-to-Amplitude Coupling and Directionality

    Science.gov (United States)

    Lozano-Soldevilla, Diego; ter Huurne, Niels; Oostenveld, Robert

    2016-01-01

    Neuronal oscillations support cognitive processing. Modern views suggest that neuronal oscillations do not only reflect coordinated activity in spatially distributed networks, but also that there is interaction between the oscillations at different frequencies. For example, invasive recordings in animals and humans have found that the amplitude of fast oscillations (>40 Hz) occur non-uniformly within the phase of slower oscillations, forming the so-called cross-frequency coupling (CFC). However, the CFC patterns might be influenced by features in the signal that do not relate to underlying physiological interactions. For example, CFC estimates may be sensitive to spectral correlations due to non-sinusoidal properties of the alpha band wave morphology. To investigate this issue, we performed CFC analysis using experimental and synthetic data. The former consisted in a double-blind magnetoencephalography pharmacological study in which participants received either placebo, 0.5 or 1.5 mg of lorazepam (LZP; GABAergic enhancer) in different experimental sessions. By recording oscillatory brain activity with during rest and working memory (WM), we were able to demonstrate that posterior alpha (8–12 Hz) phase was coupled to beta-low gamma band (20–45 Hz) amplitude envelope during all sessions. Importantly, bicoherence values around the harmonics of the alpha frequency were similar both in magnitude and topographic distribution to the cross-frequency coherence (CFCoh) values observed in the alpha-phase to beta-low gamma coupling. In addition, despite the large CFCoh we found no significant cross-frequency directionality (CFD). Critically, simulations demonstrated that a sizable part of our empirical CFCoh between alpha and beta-low gamma coupling and the lack of CFD could be explained by two-three harmonics aligned in zero phase-lag produced by the physiologically characteristic alpha asymmetry in the amplitude of the peaks relative to the troughs. Furthermore, we

  4. Neuronal oscillations with non-sinusoidal morphology produce spurious phase-to-amplitude coupling and directionality.

    Directory of Open Access Journals (Sweden)

    Diego Lozano-Soldevilla

    2016-08-01

    Full Text Available Neuronal oscillations support cognitive processing. Modern views suggest that neuronal oscillations do not only reflect coordinated activity in spatially distributed networks, but also that there is interaction between the oscillations at different frequencies. For example, invasive recordings in animals and humans have found that the amplitude of fast oscillations (> 40 Hz occur non-uniformly within the phase of slower oscillations, forming the so-called cross-frequency coupling (CFC. However, the CFC patterns be influenced by features in the signal that do not relate to underlying physiological interactions. For example, CFC estimates may be sensitive to spectral correlations due to non-sinusoidal properties of the alpha band wave morphology. To investigate this issue, we performed CFC analysis using experimental and synthetic data. The former consisted in a double-blind magnetoencephalography pharmacological study in which participants received either placebo, 0.5 mg or 1.5 mg of lorazepam (LZP; GABAergic enhancer in different experimental sessions. By recording oscillatory brain activity with during rest and working memory (WM, we were able to demonstrate that posterior alpha (8 – 12 Hz phase was coupled to beta-low gamma band (20 – 45 Hz amplitude envelope during all sessions. Importantly, bicoherence values around the harmonics of the alpha frequency were similar both in magnitude and topographic distribution to the cross-frequency coherence (CFCoh values observed in the alpha-phase to beta-low gamma coupling. In addition, despite the large CFCoh we found no significant cross-frequency directionality (CFD. Critically, simulations demonstrated that a sizable part of our empirical CFCoh between alpha and beta-low gamma coupling and the lack of CFD could be explained by two-three harmonics aligned in zero phase-lag produced by the physiologically characteristic alpha asymmetry in the amplitude of the peaks relative to the troughs

  5. Mechanisms of arm-tip regeneration in the sea star, Leptasterias hexactis.

    Science.gov (United States)

    Mladenov, Philip V; Bisgrove, Brent; Asotra, Satish; Burke, Robert D

    1989-05-01

    Wound healing and regeneration following amputation of arm-tips of the sea star, Leptasterias hexactis, are described using light microscopy, SEM, TEM, and [ 3 H] thymidine autoradiography. The process can be divided into a number of stages. Initially, the wound is closed by contractions of the stump-tip. Re-epithelialization then occurs through migration of epidermal cells from adjacent areas over the wound to form a thin wound epidermis. This is converted into a thicker, permanent covering in concurrence with the onset of cell cycle activity in the wound epidermis and adjacent epidermal regions. Histolysis and phagocytosis of damaged tissues occur beneath the new epidermis and a small connective tissue scar develops at the wound site within which muscle differentiates. At this time, elevated levels of [ 3 H]thymidine incorporation are initiated in the sub-epidermal tissues of the arm-tip. A variety of differentiated cell types enter the cell cycle including cells of the parietal peritoneum, lining of the radial water canal, and the dermis. Cell division is accompanied by the development of a small new arm-tip complete with terminal ossicle, terminal tentacle, and optic cushion. The radial water canal, radial nerve, and perivisceral coelom extend by outgrowth into this newly developing tip. Accelerated growth of the regenerate then occurs in a zone just proximal to the new tip. There is no evidence of a blastema-like mass of rapidly dividing undifferentiated cells at the tip of regenerating arms. Arm-tip regeneration in this sea star may therefore be best described as a morphallactic-like process in which a true blastema is not formed, but in which scattered cell proliferation plays an essential role.

  6. Use of stable isotopes to investigate keratin deposition in the claw tips of ducks.

    Science.gov (United States)

    Hopkins, John B; Cutting, Kyle A; Warren, Jeffrey M

    2013-01-01

    Stable isotopes derived from the claws of birds could be used to determine the migratory origins of birds if the time periods represented in excised sections of claws were known. We investigated new keratin growth in the claws of adult female Lesser Scaup (Aythya affinis) by estimating the equilibration rates of stable isotopes (δ (13)C, δ (15)N, and δ (2)H) from the breeding grounds into 1 mm claw tips. We sampled birds on their breeding ground through time and found that it took approximately 3-3.5 months for isotope values in most claw tips to equilibrate to isotope values that reflected those present in the environment on their breeding grounds. Results from this study suggest that isotopes equilibrate slowly into claw tips of Lesser Scaup, suggesting isotopes could potentially be used to determine the wintering grounds of birds. We suggest using controlled feeding experiments or longitudinal field investigations to understand claw growth and isotopic equilibration in claw tips. Such information would be valuable in ascertaining whether claw tips can be used in future studies to identify the migratory origins of birds.

  7. Flagellum motion in 2-D: Work rate and efficiency of the non-sinusoidal approach

    Science.gov (United States)

    Viridi, Sparisoma; Nuraini, Nuning; Stephanie, Monica; Rifqi, Ainur; Christina, Dina; Thania, Elsa; Sihite, Erland

    2018-03-01

    Today microorganisms have been widely used to support human life. Some examples include foodstuffs (Spirulina.sp), to help with medical needs, for mining purposes and more. On the other hand, the development of technology is also very big influence on human life. The combination of technology and health science will be very useful if we can develop it. One is the cancer treatment by utilizing the movement of the flagella to be made a nanorobot used as a carrier of cancer drugs. Movement of flagella that resembles the shape of the arc and straight line can be searched formulation and then applied to the manufacture of nanorobot tail. Then the nanorobot will carry a cancer drug that leads directly to the cancer cells. So hopefully with this nanorobot, can minimize the death of healthy cells around cancer cells. From the results of research and analysis of the movement of flagella, it can be concluded that the smaller the mass of the flagella, the greater the efficiency will be or will be more efficient. So, the energy needed nanorobot will be smaller. Model with non-sinusoidal approach (Brokaw, 1965) is discussed in this work and formulation to get the energy efficiency is proposed and analyzed. Unfortunately, there is a negative value in the formulation.

  8. Measurement of electroosmotic and electrophoretic velocities using pulsed and sinusoidal electric fields.

    Science.gov (United States)

    Sadek, Samir H; Pimenta, Francisco; Pinho, Fernando T; Alves, Manuel A

    2017-04-01

    In this work, we explore two methods to simultaneously measure the electroosmotic mobility in microchannels and the electrophoretic mobility of micron-sized tracer particles. The first method is based on imposing a pulsed electric field, which allows to isolate electrophoresis and electroosmosis at the startup and shutdown of the pulse, respectively. In the second method, a sinusoidal electric field is generated and the mobilities are found by minimizing the difference between the measured velocity of tracer particles and the velocity computed from an analytical expression. Both methods produced consistent results using polydimethylsiloxane microchannels and polystyrene micro-particles, provided that the temporal resolution of the particle tracking velocimetry technique used to compute the velocity of the tracer particles is fast enough to resolve the diffusion time-scale based on the characteristic channel length scale. Additionally, we present results with the pulse method for viscoelastic fluids, which show a more complex transient response with significant velocity overshoots and undershoots after the start and the end of the applied electric pulse, respectively. © 2016 The Authors. Electrophoresis published by Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Mixed Over-Voltage Decomposition Using Atomic Decompositions Based on a Damped Sinusoids Atom Dictionary

    Directory of Open Access Journals (Sweden)

    Lin Chen

    2011-09-01

    Full Text Available The main purpose of this paper is to establish a signal decomposition system aiming at mixed over-voltages in power systems. In an electric power system, over-voltage presents a great threat for the system safety. Analysis and identification of over-voltages is helpful to improve the stability and safety of power systems. Through statistical analysis of a collection of field over-voltage records, it was found that a kind of complicated signals created by mixing of multiple different over-voltages is difficult to identify correctly with current classification algorithms. In order to improve the classification and identification accuracy of over-voltages, a mixed over-voltage decomposition system based on the atomic decomposition and a damped sinusoid atom dictionary has been established. This decomposition system is optimized by using particle swarm optimization and the fast Fourier transform. Aiming at possible fault decomposition results during decomposition of the over-voltage signal, a double-atom decomposition algorithm is proposed in this paper. By taking three typical mixed over-voltages as examples, the validity of the algorithm is demonstrated.

  10. Effects of chronic alcoholism in the sensitivity to luminance contrast in vertical sinusoidal gratings

    Directory of Open Access Journals (Sweden)

    Éllen Dias Nicácio da Cruz

    2016-01-01

    Full Text Available Abstract The aim of this study was to measure visual contrast sensitivity (CS of luminance using vertical sinusoidal gratings with spatial frequencies of 0.6, 2.5, 5.0 and 20.0 cycles per degree of visual angle in chronic alcoholics in abstinence period. The participants were 20 volunteers (26–59 years of age divided into two groups: the study group (SG consisted of 10 volunteers with a clinical history of chronic alcoholism abstinence and the control group (CG consisted of 10 healthy volunteers. Each group had five female and five male participants. All participants had normal or corrected visual acuity and were free of identifiable diseases. The psychophysical method of forced choice between two temporal alternatives (2AFC was used to measure visual CS of luminance of 41.2 cd/m2. The results showed significant differences between groups for all spatial frequencies tested (p< 0.001. These results suggest alterations in the visual perception related to chronic alcohol consumption even after years of abstinence.

  11. Sensorless Sinusoidal Drives for Fan and Pump Motors by V/f Control

    Science.gov (United States)

    Kiuchi, Mitsuyuki; Ohnishi, Tokuo

    This paper proposes sensorless sinusoidal driving methods of permanent magnet synchronous motors for fans and pumps by V/f control. The proposed methods are simple methods that control the motor peak current constant by voltage or frequency control, and are characterized by DC link current detection using a single shunt resistor at carrier wave signal bottom timing. As a result of the dumping factor from square torque load characteristics of fan and pump motors, it is possible to control stable starting and stable steady state by V/f control. In general, pressure losses as a result of the fluid pass of fan and pump systems are nearly constant; therefore, the flow rate and motor torque are determined by revolutions. Accordingly, high efficiency driving is possible by setting corresponding currents to q-axis currents (torque currents) at target revolutions. Because of the simple current detection and motor control methods, the proposed methods are optimum for fan and pump motor driving systems of home appliances.

  12. Fine tuning of optical signals in nanoporous anodic alumina photonic crystals by apodized sinusoidal pulse anodisation.

    Science.gov (United States)

    Santos, Abel; Law, Cheryl Suwen; Chin Lei, Dominique Wong; Pereira, Taj; Losic, Dusan

    2016-11-03

    In this study, we present an advanced nanofabrication approach to produce gradient-index photonic crystal structures based on nanoporous anodic alumina. An apodization strategy is for the first time applied to a sinusoidal pulse anodisation process in order to engineer the photonic stop band of nanoporous anodic alumina (NAA) in depth. Four apodization functions are explored, including linear positive, linear negative, logarithmic positive and logarithmic negative, with the aim of finely tuning the characteristic photonic stop band of these photonic crystal structures. We systematically analyse the effect of the amplitude difference (from 0.105 to 0.840 mA cm -2 ), the pore widening time (from 0 to 6 min), the anodisation period (from 650 to 950 s) and the anodisation time (from 15 to 30 h) on the quality and the position of the characteristic photonic stop band and the interferometric colour of these photonic crystal structures using the aforementioned apodization functions. Our results reveal that a logarithmic negative apodisation function is the most optimal approach to obtain unprecedented well-resolved and narrow photonic stop bands across the UV-visible-NIR spectrum of NAA-based gradient-index photonic crystals. Our study establishes a fully comprehensive rationale towards the development of unique NAA-based photonic crystal structures with finely engineered optical properties for advanced photonic devices such as ultra-sensitive optical sensors, selective optical filters and all-optical platforms for quantum computing.

  13. Blood-borne LPS is rapidly eliminated by liver sinusoidal endothelial cells via HDL

    Science.gov (United States)

    Yao, Zhili; Mates, Jessica M.; Cheplowitz, Alana M.; Hammer, Lindsay P.; Maiseyeu, Andrei; Phillips, Gary S.; Wewers, Mark D.; Rajaram, Murugesan V.S.; Robinson, John M.; Anderson, Clark L.; Ganesan, Latha P.

    2016-01-01

    During Gram-negative bacterial infections, excessive lipopolysaccharide (LPS) induces inflammation and sepsis via action on immune cells. However, the bulk of LPS can be cleared from circulation by the liver. Liver clearance is thought to be a slow process mediated exclusively by phagocytic resident macrophages, Kupffer cells (KC). However, we discovered that LPS disappears rapidly from the circulation, with a half-life of 2–4 minutes in mice and liver eliminates about three quarters of LPS from blood circulation. Using microscopic techniques, we found that ~75% of fluor-tagged LPS in liver became associated with liver sinusoidal endothelial cells (LSEC) and only ~25% with KC. Notably, the ratio of LSEC-KC associated LPS remained unchanged 45 min after infusion, indicating that LSEC independently processes the LPS. Most interestingly, results of kinetic analysis of LPS bioactivity, using modified limulus amebocyte lysate assay, suggest that recombinant factor-C, an LPS binding protein, competitively inhibits HDL-mediated LPS association with LSEC early in the process. Supporting the previous notion 3 min post-infusion, 75% of infused fluorescently-tagged LPS-HDL complex associates with LSEC, suggesting that HDL facilitates LPS clearance. These results lead us to propose a new paradigm of LSEC and HDL in clearing LPS with a potential to avoid inflammation during sepsis. PMID:27534554

  14. Optimization of the sinusoidal phase modulation technique in resonant fiber optic gyro

    Science.gov (United States)

    Wang, Linglan; Li, Hanzhao; Zhang, Jianjie; Ma, Huilian; Jin, Zhonghe

    2017-03-01

    The sinusoidal wave phase modulation and demodulation have been widely used in the signal processing system of the resonant fiber optic gyro (RFOG). An appropriate selection of the modulation frequency is of great importance, for the frequency value directly affects the slope of the demodulation curve at the resonance point which carries the gyro output information. A large demodulation slope is pursued in a high-performance RFOG. In this paper, an analytical expression of the demodulation slope is for the first time deduced in both transmission-type and reflection-type fiber ring resonators without any approximation. The relationship between the slope value and the modulation frequency at the resonance point is accurately calculated. The calculated best modulation frequency maximizing the demodulation slope at the resonance point is different from previous widely used optimal frequency given by the Lorentzian approximation method. More importantly, both theoretical and experimental results indicate that the achieved maximal demodulation slope from the proposed analytical expression method is double of that obtaining from the Lorentzian approximation method.

  15. Engraftment and reconstitution of hematopoiesis is dependent on VEGFR2 mediated regeneration of sinusoidal endothelial cells

    Science.gov (United States)

    Hooper, Andrea T.; Butler, Jason M.; Nolan, Daniel J; Kranz, Andrea; Iida, Kaoruko; Kobayashi, Mariko; Kopp, Hans-Georg; Shido, Koji; Petit, Isabelle; Yanger, Kilangsungla; James, Daylon; Witte, Larry; Zhu, Zhenping; Wu, Yan; Pytowski, Bronislaw; Rosenwaks, Zev; Mittal, Vivek; Sato, Thomas N.; Rafii, Shahin

    2011-01-01

    SUMMARY The phenotypic attributes and molecular determinants for the regeneration of bone marrow (BM) sinusoidal endothelial cells (SECs) and their contribution to hematopoiesis are unknown. We show that after myelosuppression VEGFR2 activation promotes reassembly of regressed SECs, reconstituting hematopoietic stem and progenitor cells (HSPCs). VEGFR2 and VEGFR3 expression are restricted to BM vasculature, demarcating a continuous network of VEGFR2+VEGFR3+Sca1− SECs and VEGFR2+VEGFR3−Sca1+ arterioles. While chemotherapy (5FU) and sublethal irradiation (650 rad) induce minor SEC regression, lethal irradiation (950 rad) induces severe regression of SECs requiring BM transplantation (BMT) for regeneration. Conditional deletion of VEGFR2 in adult mice blocks regeneration of SECs in sublethally irradiated animals, preventing hematopoietic reconstitution. Inhibition of VEGFR2 signaling in lethally irradiated wild type mice rescued with BMT severely impairs SEC reconstruction, preventing engraftment and reconstitution of HSPCs. Therefore, activation of VEGFR2 is critical for regeneration of VEGFR3+Sca1− SECs that are essential for engraftment and restoration of HSPCs and hematopoiesis. PMID:19265665

  16. Experimental study of fluid flow in the entrance of a sinusoidal channel

    International Nuclear Information System (INIS)

    Oviedo-Tolentino, F.; Romero-Mendez, R.; Hernandez-Guerrero, A.; Giron-Palomares, B.

    2008-01-01

    An experimental flow visualization study of the entrance section of channels formed with sinusoidal plates was made. The experiments were conducted in a water tunnel and a laser illuminated particle tracking was used as the technique of flow visualization. The geometric parameters of the plates were maintained constant while the distance between plates, phase angle, and the Reynolds number were varied during the experiments. The flow regimes that were found in the experiments are steady, unsteady and significantly-mixed flows. Instabilities of the flow first appear near the exit of the channel, and move closer to the inlet waves as the Reynolds number grows, but in the first wave from inlet the flow is always steady. The results show that, for all other parameters fixed, the Reynolds number at which unsteady flow first appears grows with the distance between plates. The phase angle that best promotes unsteady flow depends on the average distance between plates: for certain average distance between plates, there is a phase angle that best disturbs the flow. For the set of parameters used in this experiment, a channel with eight waves is sufficiently long and the flow features presented in the first eight waves of a longer channel will be similar to what was observed here

  17. A metabonomic evaluation of the monocrotaline-induced sinusoidal obstruction syndrome (SOS) in rats

    Energy Technology Data Exchange (ETDEWEB)

    Conotte, R.; Colet, J.-M., E-mail: jean-marie.colet@umons.ac.be

    2014-04-15

    The main curative treatment of colorectal cancer remains the surgery. However, when metastases are suspected, surgery is followed by a preventive chemotherapy using oxaliplatin which, unfortunately, may cause liver sinusoidal obstruction syndrome (SOS). Such hepatic damage is barely detected during or after chemotherapy due to a lack of effective diagnostic procedures, but liver biopsy. The primary objective of the present study was to identify potential early diagnosis biomarkers of SOS using a metabonomic approach. SOS was induced in rats by monocrotaline, a prototypical toxic substance. {sup 1}H NMR spectroscopy analysis of urine samples collected from rats treated with monocrotaline showed significant metabolic changes as compared to controls. During a first phase, cellular protective mechanisms such as an increased synthesis of GSH (reduced taurine) and the recruitment of cell osmolytes in the liver (betaine) were seen. In the second phase, the disturbance of the urea cycle (increased ornithine and urea reduction) leading to the depletion of NO, the alteration in the GSH synthesis (increased creatine and GSH precursors (glutamate, dimethylglycine and sarcosine)), and the liver necrosis (decrease taurine and increase creatine) all indicate the development of SOS. - Highlights: • Urine metabonomic profiles of SOS have been identified. • Urine osmoprotectants and anti-oxidants indicated an initial liver protection. • Liver necrosis was demonstrated by increased urine levels of taurine and creatine. • NO depletion was suggested by changes in ornithine and urea.

  18. Human liver sinusoidal endothelial cells but not hepatocytes contain factor VIII.

    Science.gov (United States)

    Shahani, T; Covens, K; Lavend'homme, R; Jazouli, N; Sokal, E; Peerlinck, K; Jacquemin, M

    2014-01-01

    Although the liver is the major site of coagulation factor VIII (FVIII) synthesis, the type of cells producing FVIII within the liver is still unclear. To measure FVIII in extracts of primary liver sinusoidal endothelial cells (LSECs) and hepatocytes, thereby preventing potential bias resulting from the modifications of the cell phenotype that can take place during in vitro culture. LSECs were purified by flow cytometry cell sorting on the basis of their coexpression of Tie2 and CD32b. The purity of the cells was controlled by RNA sequencing. FVIII activity (FVIII:C) in extracts of purified cells was measured with a sensitive FVIII chromogenic assay, in which the specificity of the reaction is controlled by neutralization of FVIII activity with specific inhibitor antibodies. The FVIII:C concentration in purified LSECs ranged from 0.3 to 2.8 nU per cell. In contrast, FVIII:C was undetectable in hepatocytes. The intracellular FVIII:C concentrations are therefore at least 10-100-fold higher in LSECs than in hepatocytes. Our data demonstrate that LSECs, but not hepatocytes, contain measurable amounts of FVIII:C, and suggest that the former are the main cells producing FVIII in the human liver. © 2013 International Society on Thrombosis and Haemostasis.

  19. Spline-based high-accuracy piecewise-polynomial phase-to-sinusoid amplitude converters.

    Science.gov (United States)

    Petrinović, Davor; Brezović, Marko

    2011-04-01

    We propose a method for direct digital frequency synthesis (DDS) using a cubic spline piecewise-polynomial model for a phase-to-sinusoid amplitude converter (PSAC). This method offers maximum smoothness of the output signal. Closed-form expressions for the cubic polynomial coefficients are derived in the spectral domain and the performance analysis of the model is given in the time and frequency domains. We derive the closed-form performance bounds of such DDS using conventional metrics: rms and maximum absolute errors (MAE) and maximum spurious free dynamic range (SFDR) measured in the discrete time domain. The main advantages of the proposed PSAC are its simplicity, analytical tractability, and inherent numerical stability for high table resolutions. Detailed guidelines for a fixed-point implementation are given, based on the algebraic analysis of all quantization effects. The results are verified on 81 PSAC configurations with the output resolutions from 5 to 41 bits by using a bit-exact simulation. The VHDL implementation of a high-accuracy DDS based on the proposed PSAC with 28-bit input phase word and 32-bit output value achieves SFDR of its digital output signal between 180 and 207 dB, with a signal-to-noise ratio of 192 dB. Its implementation requires only one 18 kB block RAM and three 18-bit embedded multipliers in a typical field-programmable gate array (FPGA) device. © 2011 IEEE

  20. Liver sinusoidal endothelial cells induce immunosuppressive IL-10-producing Th1 cells via the Notch pathway.

    Science.gov (United States)

    Neumann, Katrin; Rudolph, Christine; Neumann, Christian; Janke, Marko; Amsen, Derk; Scheffold, Alexander

    2015-07-01

    Under homeostasis, liver sinusoidal endothelial cells (LSECs) shift intrahepatic T-cell responses towards tolerance. However, the role of LSECs in the regulation of T-cell-induced liver inflammation is less clear. Here, we studied the capacity of LSECs to modulate pro-inflammatory Th1-cell differentiation in mice. Using in vitro co-culture systems and subsequent cytokine analysis, we showed that LSECs induced high amounts of the anti-inflammatory cytokine IL-10 in developing Th1 cells. These LSEC-stimulated Th1 cells had no pro-inflammatory capacity in vivo but instead actively suppressed an inflammatory Th1-cell-induced delayed-type hypersensitivity reaction. Blockage of IL-10 signaling in vivo inhibited immunosuppressive activity of LSEC-stimulated Th1 cells. We identified the Notch pathway as a mechanism how LSECs trigger IL-10 expression in Th1 cells. LSECs expressed high levels of the Delta-like and Jagged family of Notch ligands and induced expression of the Notch target genes hes-1 and deltex-1 in Th1 cells. Blockade of Notch signaling selectively inhibited IL-10 induction in Th1 cells by LSECs. Our findings suggest that LSEC-induced IL-10 expression in Th1 cells via the Notch pathway may contribute to the control of hepatic inflammatory immune responses by induction of a self-regulatory mechanism in pro-inflammatory Th1 cells. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Flame Structure and Chemiluminescence Emissions of Inverse Diffusion Flames under Sinusoidally Driven Plasma Discharges

    Directory of Open Access Journals (Sweden)

    Maria Grazia De Giorgi

    2017-03-01

    Full Text Available Reduction of nitric oxides (NOx in aircraft engines and in gas turbines by lean combustion is of great interest in the design of novel combustion systems. However, the stabilization of the flame under lean conditions is a main issue. In this context, the present work investigates the effects of sinusoidal dielectric barrier discharge (DBD on a lean inverse diffusive methane/air flame in a Bunsen-type burner under different actuation conditions. The flame appearance was investigated with fixed methane loading (mass flux, but with varying inner airflow rate. High-speed flame imaging was done by using an intensified (charge-coupled device CCD camera equipped with different optical filters in order to selectively record signals from the chemiluminescent species OH*, CH*, or CO2* to evaluate the flame behavior in presence of plasma actuation. The electrical power consumption was less than 33 W. It was evident that the plasma flame enhancement was significantly influenced by the plasma discharges, particularly at high inner airflow rates. The flame structure changes drastically when the dissipated plasma power increases. The flame area decreases due to the enhancement of mixing and chemical reactions that lead to a more anchored flame on the quartz exit with a reduction of the flame length.

  2. Elementary steps of contraction probed by sinusoidal analysis technique in rabbit psoas fibers.

    Science.gov (United States)

    Kawai, M; Zhao, Y; Halvorson, H R

    1993-01-01

    Elementary steps of contraction were probed by sinusoidal analysis technique in skinned fibers from the rabbit psoas muscle during maximal Ca2+ activation (pCa 4.55-4.82) at 20 degrees C and 200 mM ionic strength. Our study included the effects of MgATP, MgADP, and Pi concentrations, and an ATP hydrolysis rate measurement. We increased the frequency range up to 350 Hz, and resolved an extra process (D), in addition to well defined processes (A), (B), and (C). Based on these studies, we established a cross-bridge scheme consisting of six attached states, one detached state, and transitions between these states. We deduced all kinetic constants to specify the scheme. The scheme uniquely explains our data, and no other scheme with an equal degree of simplicity could explain our data. We correlated process (D) to ATP isomerization, process (C) to cross-bridge detachment, and process (B) to cross-bridge attachment. We deduced the tension per cross-bridge state, which indicates that force is generated on cross-bridge attachment and before Pi-release. We also found that the rate constants of elementary steps become progressively slower starting from ATP binding to the myosin head and ending by ADP isomerization, and this stepwise slowing may be the essential and integral part of the energy transduction mechanism by muscle.

  3. Morphology and force probing of primary murine liver sinusoidal endothelial cells.

    Science.gov (United States)

    Zapotoczny, B; Owczarczyk, K; Szafranska, K; Kus, E; Chlopicki, S; Szymonski, M

    2017-07-01

    Liver sinusoidal endothelial cells (LSECs) represent unique type of endothelial cells featured by their characteristic morphology, ie, lack of a basement membrane and presence of fenestrations-transmembrane pores acting as a dynamic filter between the vascular space and the liver parenchyma. Delicate structure of LSECs membrane combined with a submicron size of fenestrations hinders their visualization in live cells. In this work, we apply atomic force microscopy contact mode to characterize fenestrations in LSECs. We reveal the structure of fenestrations in live LSECs. Moreover, we show that the high-resolution imaging of fenestrations is possible for the glutaraldehyde-fixed LSECs. Finally, thorough information about the morphology of LSECs including great contrast in visualization of sieve plates and fenestrations is provided using Force Modulation mode. We show also the ability to precisely localize the cell nuclei in fixed LSECs. It can be helpful for more precise description of nanomechanical properties of cell nuclei using atomic force microscopy. Presented methodology combining high-quality imaging of fixed cells with an additional nanomechanical information of both live and fixed LSECs provides a unique approach to study LSECs morphology and nanomechanics that could foster understanding of the role of LSECs in maintaining liver homeostasis. Copyright © 2017 John Wiley & Sons, Ltd.

  4. Numerical simulation of turbulent flow and heat transfer though sinusoidal ducts

    Science.gov (United States)

    Abroshan, Hamid

    2018-02-01

    Turbulent forced convection heat transfer in corrugated plate surfaces was studied by means of CFD. Flow through corrugated plates, which are sets of sinusoidal ducts, was analyzed for different inlet flow angles (0° to 50°), aspect ratios (0.1 to 10), Reynolds numbers (2000 to 40,000) and Prantdel numbers (0.7 to 5). Heat transfer is affected significantly by variation of aspect ratio. A maximum heat transfer coefficient is observed at a particular aspect ratio although the aspect ratio has a minor effect on friction factor. Enlarging inlet flow angle also leads to a higher heat transfer coefficient and pressure loss in aspect ratios close to unity. Dependency of Nusselt and friction factor on the angle and aspect ratio was interpreted by means of appearance of secondary motions and coexistence of laminar and turbulent flow in a cross section. Comparing the results with experimental data shows a maximum 12.8% difference. By evaluating the results, some correlations were proposed to calculate Nusselt number and friction factor for entrance and fully developed regions. A corrugated plate with an aspect ratio equal to 1.125 and an inlet flow angle equal to 50° gives the best heat transfer and pressure drop characteristics.

  5. An Improved Walsh Function Algorithm for Use in Sinusoidal and Nonsinusoidal Power Components Measurement

    Directory of Open Access Journals (Sweden)

    Saifulnizam Bin Abdul Khalid

    2013-01-01

    Full Text Available This paper presents an improved Walsh function IWF algorithms as an alternative approach for active and reactive powers measurement in linear and nonlinear, balanced and unbalanced sinusoidal three-phase load system. It takes advantage of Walsh function unified approach, simple algorithm and its intrinsic high level of accuracy as a result of coefficient characteristics and energy behaviour representation. The developed algorithm was modeled on the Matlab Simulink software; different types of load, linear and nonlinear, were also modeled based on practical voltage and current waveforms and tested with the proposed improved Walsh algorithms. The IEEE standard 1459–2000 which is based on fast Fourier transform FFT approach was used as benchmark for the linear load system. The data obtained from laboratory experiment to determine power components in harmonic load systems using Fluke 435 power quality analyzer PQA which complies with IEC/EN61010-1-2001 standard was modeled and used to validate the improved algorithm for nonlinear load measurement. The results showed that the algorithm has the potential to effectively measure three-phase power components under different load conditions.

  6. Hepatic sinusoidal obstruction syndrome caused by herbal medicine: CT and MRI features

    International Nuclear Information System (INIS)

    Zhou, Hua; Lou, Hai Yan; Wang, Yi Xiang J.; Xu, Xiao Jun; Zhang, Min Ming

    2014-01-01

    To describe the CT and MRI features of hepatic sinusoidal obstruction syndrome (HSOS) caused by herbal medicine Gynura segetum. The CT and MRI features of 16 consecutive Gynura segetum induced HSOS cases (12 men, 4 women) were analyzed. Eight patients had CT; three patients had MRI, and the remaining five patients had both CT and MRI examinations. Based on their clinical presentations and outcomes, the patients were classified into three categories: mild, moderate, and severe. The severity of the disease was also evaluated radiologically based on the abnormal hepatic patchy enhancement in post-contrast CT or MRI images. Ascites, patchy liver enhancement, and main right hepatic vein narrowing or occlusion were present in all 16 cases. Hepatomegaly and gallbladder wall thickening were present in 14 cases (87.5%, 14/16). Periportal high intensity on T2-weighted images was present in 6 cases (75%, 6/8). Normal liver parenchymal enhancement surrounding the main hepatic vein forming a clover-like sign was observed in 4 cases (25%, 4/16). The extent of patchy liver enhancement was statistically associated with clinical severity classification (kappa = 0.565). Ascites, patchy liver enhancement, and the main hepatic veins narrowing were the most frequent signs of herbal medicine induced HSOS. The grade of abnormal patchy liver enhancement was associated with the clinical severity.

  7. Hepatic sinusoidal obstruction syndrome caused by herbal medicine: CT and MRI features

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Hua; Lou, Hai Yan [Dept. of Radiology, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou (China); Wang, Yi Xiang J. [Dept. of Radiology, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou (China); Xu, Xiao Jun; Zhang, Min Ming [Dept. of Radiology, The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou (China)

    2014-04-15

    To describe the CT and MRI features of hepatic sinusoidal obstruction syndrome (HSOS) caused by herbal medicine Gynura segetum. The CT and MRI features of 16 consecutive Gynura segetum induced HSOS cases (12 men, 4 women) were analyzed. Eight patients had CT; three patients had MRI, and the remaining five patients had both CT and MRI examinations. Based on their clinical presentations and outcomes, the patients were classified into three categories: mild, moderate, and severe. The severity of the disease was also evaluated radiologically based on the abnormal hepatic patchy enhancement in post-contrast CT or MRI images. Ascites, patchy liver enhancement, and main right hepatic vein narrowing or occlusion were present in all 16 cases. Hepatomegaly and gallbladder wall thickening were present in 14 cases (87.5%, 14/16). Periportal high intensity on T2-weighted images was present in 6 cases (75%, 6/8). Normal liver parenchymal enhancement surrounding the main hepatic vein forming a clover-like sign was observed in 4 cases (25%, 4/16). The extent of patchy liver enhancement was statistically associated with clinical severity classification (kappa = 0.565). Ascites, patchy liver enhancement, and the main hepatic veins narrowing were the most frequent signs of herbal medicine induced HSOS. The grade of abnormal patchy liver enhancement was associated with the clinical severity.

  8. Unsteady flow damping force prediction of MR dampers subjected to sinusoidal loading

    Science.gov (United States)

    Yu, M.; Wang, S. Q.; Fu, J.; Peng, Y. X.

    2013-02-01

    So far quasi-steady models are usually used to design magnetorheological (MR) dampers, but these models are not sufficient to describe the MR damper behavior under unsteady dynamic loading, for fluid inertia is neglected in quasi-steady models, which will bring more error between computer simulation and experimental results. Under unsteady flow model, the fluid inertia terms will bring error calculated upto 10%, so it is necessary to be considered in the governing equation. In this paper, force-stroke behavior of MR damper with flow mode due to sinusoidal loading excitation is mainly investigated, to simplify the analysis, the one-dimensional axisymmetric annular duct geometry of MR dampers is approximated as a rectangular duct. The rectangular duct can be divided into 3 regions for the velocity profile of the incompressible MR fluid flow, in each region, a partial differential equation is composed of by Navier-Stokes equations, boundary conditions and initial conditions to determine the velocity solution. In addition, in this work, not only Bingham plastic model but the Herschel—Bulkley model is adopted to analyze the MR damper performance. The damping force resulting from the pressure drop of unsteady MR dampers can be obtained and used to design or size MR dampers. Compared with the quasi-steady flow damping force, the damping force of unsteady MR dampers is more close to practice, particularly for the high-speed unsteady movement of MR dampers.

  9. Unsteady flow damping force prediction of MR dampers subjected to sinusoidal loading

    International Nuclear Information System (INIS)

    Yu, M; Fu, J; Wang, S Q; Peng, Y X

    2013-01-01

    So far quasi-steady models are usually used to design magnetorheological (MR) dampers, but these models are not sufficient to describe the MR damper behavior under unsteady dynamic loading, for fluid inertia is neglected in quasi-steady models, which will bring more error between computer simulation and experimental results. Under unsteady flow model, the fluid inertia terms will bring error calculated upto 10%, so it is necessary to be considered in the governing equation. In this paper, force-stroke behavior of MR damper with flow mode due to sinusoidal loading excitation is mainly investigated, to simplify the analysis, the one-dimensional axisymmetric annular duct geometry of MR dampers is approximated as a rectangular duct. The rectangular duct can be divided into 3 regions for the velocity profile of the incompressible MR fluid flow, in each region, a partial differential equation is composed of by Navier-Stokes equations, boundary conditions and initial conditions to determine the velocity solution. In addition, in this work, not only Bingham plastic model but the Herschel—Bulkley model is adopted to analyze the MR damper performance. The damping force resulting from the pressure drop of unsteady MR dampers can be obtained and used to design or size MR dampers. Compared with the quasi-steady flow damping force, the damping force of unsteady MR dampers is more close to practice, particularly for the high-speed unsteady movement of MR dampers.

  10. Diagnostic performance of Contrast-enhanced CT in Pyrrolizidine Alkaloids-induced Hepatic Sinusoidal Obstructive Syndrome

    Science.gov (United States)

    Kan, Xuefeng; Ye, Jin; Rong, Xinxin; Lu, Zhiwen; Li, Xin; Wang, Yong; Yang, Ling; Xu, Keshu; Song, Yuhu; Hou, Xiaohua

    2016-01-01

    Hepatic sinusoidal obstruction syndrome (HSOS) can be caused by pyrrolizidine alkaloids(PAs)-containing herbals. Since PAs exposure is obscure and clinical presentation of HSOS is unspecific, it is challenge to establish the diagnosis of PAs-induced HSOS. Gynura segetum is one of the most wide-use herbals containing PAs. The aim of our study is to describe the features of contrast-enhanced computed tomography (CT) in gynura segetum-induced HSOS, and then determine diagnostic performance of radiological signs. We retrospectively analyzed medical records and CT images of HSOS patients (71 cases) and the controls (222 cases) enrolled from January 1, 2008, to Oct 31, 2015. The common findings of contrast CT in PAs-induced HSOS included: ascites (100%), hepatomegaly (78.87%), gallbladder wall thickening (86.96%), pleural effusion (70.42%), hepatic vein narrowing (87.32%), patchy liver enhancement (92.96%), and heterogeneous hypoattenuation (100%); of these signs, patchy enhancement and heterogeneous hypoattenuation were valuable features. Then, the result of diagnostic performance demonstrated that contrast CT possessed better performance in diagnosing PAs-induced HSOS compared with various parameters of Seattle criteria. In conclusion, the patients with PAs-induced HSOS display distinct radiologic features at CT-scan, which reveals that contrast-enhanced CT provides an effective noninvasive method for diagnosing PAs-induced HSOS. PMID:27897243

  11. Using spatiotemporal source separation to identify prominent features in multichannel data without sinusoidal filters.

    Science.gov (United States)

    Cohen, Michael X

    2017-09-27

    The number of simultaneously recorded electrodes in neuroscience is steadily increasing, providing new opportunities for understanding brain function, but also new challenges for appropriately dealing with the increase in dimensionality. Multivariate source separation analysis methods have been particularly effective at improving signal-to-noise ratio while reducing the dimensionality of the data and are widely used for cleaning, classifying and source-localizing multichannel neural time series data. Most source separation methods produce a spatial component (that is, a weighted combination of channels to produce one time series); here, this is extended to apply source separation to a time series, with the idea of obtaining a weighted combination of successive time points, such that the weights are optimized to satisfy some criteria. This is achieved via a two-stage source separation procedure, in which an optimal spatial filter is first constructed and then its optimal temporal basis function is computed. This second stage is achieved with a time-delay-embedding matrix, in which additional rows of a matrix are created from time-delayed versions of existing rows. The optimal spatial and temporal weights can be obtained by solving a generalized eigendecomposition of covariance matrices. The method is demonstrated in simulated data and in an empirical electroencephalogram study on theta-band activity during response conflict. Spatiotemporal source separation has several advantages, including defining empirical filters without the need to apply sinusoidal narrowband filters. © 2017 Federation of European Neuroscience Societies and John Wiley & Sons Ltd.

  12. Sinusoidal Parameter Estimation Using Quadratic Interpolation around Power-Scaled Magnitude Spectrum Peaks

    Directory of Open Access Journals (Sweden)

    Kurt James Werner

    2016-10-01

    Full Text Available The magnitude of the Discrete Fourier Transform (DFT of a discrete-time signal has a limited frequency definition. Quadratic interpolation over the three DFT samples surrounding magnitude peaks improves the estimation of parameters (frequency and amplitude of resolved sinusoids beyond that limit. Interpolating on a rescaled magnitude spectrum using a logarithmic scale has been shown to improve those estimates. In this article, we show how to heuristically tune a power scaling parameter to outperform linear and logarithmic scaling at an equivalent computational cost. Although this power scaling factor is computed heuristically rather than analytically, it is shown to depend in a structured way on window parameters. Invariance properties of this family of estimators are studied and the existence of a bias due to noise is shown. Comparing to two state-of-the-art estimators, we show that an optimized power scaling has a lower systematic bias and lower mean-squared-error in noisy conditions for ten out of twelve common windowing functions.

  13. In-vitro study on haemodiluted blood flow in a sinusoidal microstenosis.

    Science.gov (United States)

    Kang, M J; Ji, H-S; Lee, S J

    2010-01-01

    In-vitro experiments were carried out to investigate the haemodynamic and haemorheological behaviours of haemodiluted blood flow through a microstenosis using a micro-particle image velocimetry (PIV) technique. The micro-PIV system employed in this study consisted of a two-head neodymium:yttrium-aluminium-garnet (Nd:YAG) laser, a cooled charge-coupled device camera, and a delay generator. To simulate blood flow in a stenosed vascular vessel, a polydimethylsiloxane (PDMS) microchannel with a sinusoidal throat of 80 per cent severity was employed. The width and depth of the microchannel were 100 microm and 50 microm, respectively. To compare the flow characteristics in the microstenosis, the same experiments were repeated in a straight microchannel under the same flow conditions. Using a syringe pump, human blood with 5 per cent haematocrit was supplied into the microstenosis channel. The flow characteristics and transport of blood cells through the microstenosis were investigated with various flowrates. The mean velocity fields were nearly symmetric with respect to the channel centreline. In the contraction section, the oncoming blood flow was accelerated rapidly, and the maximum velocity at the throat was almost 4.99 times faster than that of the straight microchannel without stenosis. In the diffusion section, the blood cells show rolling, deformation, twisting, and tumbling motion due to the flow-choking characteristics at the stenotic region. The results from this study will provide useful basic data for comparison with those obtained by clinical researchers.

  14. Thermodynamic analysis of fluid flow in channels with wavy sinusoidal walls

    Directory of Open Access Journals (Sweden)

    Bahaidarah Haitham M.S.

    2013-01-01

    Full Text Available Entropy generation in channels with non-uniform cross-section that can be found in many fluid flow systems is an important concern from the thermodynamic design point of view. In this regard, the entropy generation in channels with periodic wavy sinusoidal walls has been considered in present study. The flow is assumed to be two-dimensional steady laminar and the main parameters considered are the Re number, height ratio Hmin/Hmax and module length ratio L/a. The fluid enters the channel with uniform axial velocity and temperature. The wall of the channel is assumed to be at uniform temperature which is different that of the fluid at the inlet of the channel. The distribution of the entropy generation as well as the total entropy generation has been studied numerically. It is found that the Re number and the geometric parameters, height ratio and module length ratio have significant effect on both the local concentrations of entropy generation as well as the total entropy generation in the channel. Flow separation and re-circulation size, strength and location of flow are found to be major concern in determining the local entropy generation.

  15. A high current sinusoidal pulse generator for the diluter magnets of the LHC beam dump system

    CERN Document Server

    Vossenberg, Eugène B; Ducimetière, L; Schröder, G H

    2000-01-01

    CERN is constructing the Large Hadron Collider (LHC), a superconducting accelerator that will collide protons at a center of mass energy of 14 TeV. The two colliding beams will each store an energy of up to 540 MJ, which must be safely deposited within one beam revolution of 89 mu s on two external absorbers located about 700 m from the extraction points at the end of dedicated extraction tunnels. To avoid evaporation of the graphite absorber material by the very high energy density of the incident beams, the deposition area of the beams on the absorber front face will be increased. This is done by a pair of sinusoidally powered orthogonal magnet systems producing approximately an e-shape figure of about 35 mm diameter, with a minimum velocity of 10 mm/ mu s during the dumping process. The pulse generators of the horizontally and vertically deflecting diluter magnets are composed of capacitor banks, discharged by stacks of solid state closing switches. They are connected to the magnets by 28 m long low induct...

  16. 78 FR 13402 - Proposed Collection; Comment Request for Tip Reporting Alternative Tip Agreement Used in the...

    Science.gov (United States)

    2013-02-27

    ... Used in the Cosmetology and Barber Industry AGENCY: Internal Revenue Service (IRS), Treasury. ACTION..., the IRS is soliciting comments concerning tip reporting alternative commitment used in the cosmetology...: Tip Reporting Alternative Commitment Agreement used in the Cosmetology and Barber Industry. OMB Number...

  17. 75 FR 11226 - Proposed Collection; Comment Request for Tip Reporting Alternative Tip Agreement Used in the...

    Science.gov (United States)

    2010-03-10

    ... Used in the Cosmetology and Barber Industry AGENCY: Internal Revenue Service (IRS), Treasury. ACTION..., the IRS is soliciting comments concerning Tip Reporting Alternative Commitment used in the Cosmetology...: Tip Reporting Alternative Commitment Agreement used in the Cosmetology and Barber Industry. OMB Number...

  18. Tip vortices in the actuator line model

    Science.gov (United States)

    Martinez, Luis; Meneveau, Charles

    2017-11-01

    The actuator line model (ALM) is a widely used tool to represent the wind turbine blades in computational fluid dynamics without the need to resolve the full geometry of the blades. The ALM can be optimized to represent the `correct' aerodynamics of the blades by choosing an appropriate smearing length scale ɛ. This appropriate length scale creates a tip vortex which induces a downwash near the tip of the blade. A theoretical frame-work is used to establish a solution to the induced velocity created by a tip vortex as a function of the smearing length scale ɛ. A correction is presented which allows the use of a non-optimal smearing length scale but still provides the downwash which would be induced using the optimal length scale. Thanks to the National Science Foundation (NSF) who provided financial support for this research via Grants IGERT 0801471, IIA-1243482 (the WINDINSPIRE project) and ECCS-1230788.

  19. Tipping elements in the Arctic marine ecosystem.

    Science.gov (United States)

    Duarte, Carlos M; Agustí, Susana; Wassmann, Paul; Arrieta, Jesús M; Alcaraz, Miquel; Coello, Alexandra; Marbà, Núria; Hendriks, Iris E; Holding, Johnna; García-Zarandona, Iñigo; Kritzberg, Emma; Vaqué, Dolors

    2012-02-01

    The Arctic marine ecosystem contains multiple elements that present alternative states. The most obvious of which is an Arctic Ocean largely covered by an ice sheet in summer versus one largely devoid of such cover. Ecosystems under pressure typically shift between such alternative states in an abrupt, rather than smooth manner, with the level of forcing required for shifting this status termed threshold or tipping point. Loss of Arctic ice due to anthropogenic climate change is accelerating, with the extent of Arctic sea ice displaying increased variance at present, a leading indicator of the proximity of a possible tipping point. Reduced ice extent is expected, in turn, to trigger a number of additional tipping elements, physical, chemical, and biological, in motion, with potentially large impacts on the Arctic marine ecosystem.

  20. La red sobre trabajo infantil peligroso (Red Tip The hazardous child labor network (Red Tip

    Directory of Open Access Journals (Sweden)

    Walter Varillas

    2003-01-01

    Full Text Available En el mundo, aproximadamente 351.7 millones de niños entre 5 y 17 años realizaban algún tipo de actividad económica, de ellos 170.5 millones (48.5% realizaban algún tipo de trabajo considerado peligroso. Un alto porcentaje se encuentra en la agricultura, otros en minas, manufacturas, ladrilleras, predominantemente en la economía informal. El Convenio 138 (cobre la edad mínima de admisión en el empleo de la OIT y el Convenio 182 (sobre las peores formas de trabajo infantil, definen como trabajo infantil peligroso el que puede afectar la salud, seguridad y moralidad de los menores. Estudios específicos sobre los menores muestran su susceptibilidad particular frente a los riesgos laborales, aumentando la peligrosidad para su normal desarrollo y crecimiento: "los niños no son adultos pequeños". Los profesionales de la seguridad y salud en el trabajo pueden colaborar con los profesionales y las organizaciones especializadas en el trabajo infantil, en la definición y caracterización de lo que significa el trabajo infantil peligroso. Para ello se ha conformado la Red sobre Trabajo Infantil Peligroso (Red TIP, con la finalidad de articular estos dos espacios, orientados a eliminar el trabajo infantil peligroso y rescatar al menor y devolverle la oportunidad de sonreír ahora y en el futuro.In the world, approximately 351.7 millions children between 5 and 17 years old work. Of them, 170,5 millions (48.5% work at the hazardous child labor forms. A high percentage is in agriculture, others in mines, manufactures, brick makers, predominantly in informal economy. The 138 Convention of ILO and the 182 Convention, define as hazardous child labor activities that can affect the health, safety and morality of the children. Studies on the children at work point out their particular susceptibility to some occupational risks, increasing the danger for their normal development and growth. "They are not little adults". The occupational health

  1. Computer simulation of creep damage at crack tip in short fibre composites

    Science.gov (United States)

    Shuangyin, Zhang; Tsai, L. W.

    1994-08-01

    Creep damage at crack tip in short fibre composites has been simulated by using the finite element method (FEM). The well-known Schapery non-linear viscoelastic constitutive relationship was used to characterize time-dependent behaviour of the material. A modified recurrence equation was adopted to accelerate the iteration. Kachanov-Rabotnov's damage evolution law was employed. The growth of the damage zone with time around the crack tip was calculated and the results were shown with the so-called “digit photo”, which was produced by the printer.

  2. The electronic states calculated using the sinusoidal potential for Cd1-xZnxS quantum dot superlattices

    International Nuclear Information System (INIS)

    Sakly, A.; Safta, N.; Mejri, H.; Lamine, A. Ben

    2011-01-01

    Research highlights: → This paper is dedicated to structures based on Cd 1-x Zn x S. - Abstract: The present work reports on a theoretical investigation of superlattices based on Cd 1-x Zn x S quantum dots embedded in an insulating material. The system to model is assumed to be a series of flattened cylindrical quantum dots with a finite barrier at the boundary and is studied using a sinusoidal potential. The electronic states of both Γ 1 - (ground) and Γ 2 - (first excited) minibands have been computed as a function of inter-quantum dot separation and Zn composition. An analysis of the results shows that the widths of Γ 1 - and Γ 2 - minibands decrease as the superlattice period and Zn content increase separately. Moreover, the sinusoidal shape of the confining potential accounts for the coupling between quantum dots quantitatively less than the Kronig-Penney potential model.

  3. An all digital phase locked loop for synchronization of a sinusoidal signal embedded in white Gaussian noise

    Science.gov (United States)

    Reddy, C. P.; Gupta, S. C.

    1973-01-01

    An all digital phase locked loop which tracks the phase of the incoming sinusoidal signal once per carrier cycle is proposed. The different elements and their functions and the phase lock operation are explained in detail. The nonlinear difference equations which govern the operation of the digital loop when the incoming signal is embedded in white Gaussian noise are derived, and a suitable model is specified. The performance of the digital loop is considered for the synchronization of a sinusoidal signal. For this, the noise term is suitably modelled which allows specification of the output probabilities for the two level quantizer in the loop at any given phase error. The loop filter considered increases the probability of proper phase correction. The phase error states in modulo two-pi forms a finite state Markov chain which enables the calculation of steady state probabilities, RMS phase error, transient response and mean time for cycle skipping.

  4. Tip-Based Nanofabrication for Scalable Manufacturing

    Directory of Open Access Journals (Sweden)

    Huan Hu

    2017-03-01

    Full Text Available Tip-based nanofabrication (TBN is a family of emerging nanofabrication techniques that use a nanometer scale tip to fabricate nanostructures. In this review, we first introduce the history of the TBN and the technology development. We then briefly review various TBN techniques that use different physical or chemical mechanisms to fabricate features and discuss some of the state-of-the-art techniques. Subsequently, we focus on those TBN methods that have demonstrated potential to scale up the manufacturing throughput. Finally, we discuss several research directions that are essential for making TBN a scalable nano-manufacturing technology.

  5. Social tipping points and Earth systems dynamics

    Directory of Open Access Journals (Sweden)

    R. Alexander eBentley

    2014-08-01

    Full Text Available Recently, Early Warning Signals (EWS have been developed to predict tipping points in Earth Systems. This discussion highlights the potential to apply EWS to human social and economic systems, which may also undergo similar critical transitions. Social tipping points are particularly difficult to predict, however, and the current formulation of EWS, based on a physical system analogy, may be insufficient. As an alternative set of EWS for social systems, we join with other authors encouraging a focus on heterogeneity, connectivity through social networks and individual thresholds to change.

  6. Windows 7 Annoyances Tips, Secrets, and Solutions

    CERN Document Server

    Karp, David

    2010-01-01

    Windows 7 may be faster and more stable than Vista, but it's a far cry from problem-free. David A. Karp comes to the rescue with the latest in his popular Windows Annoyances series. This thorough guide gives you the tools you need to fix the troublesome parts of this operating system, plus the solutions, hacks, and timesaving tips to make the most of your PC. Streamline Windows Explorer, improve the Search tool, eliminate the Green Ribbon of Death, and tame User Account Control promptsExplore powerful Registry tips and tools, and use them to customize every aspect of Windows and solve its sho

  7. Associations between levels of insulin-like growth factor 1 and sinusoidal obstruction syndrome after allogeneic haematopoietic stem cell transplantation

    DEFF Research Database (Denmark)

    Weischendorff, Sarah; Kielsen, Katrine; Sengeløv, H

    2017-01-01

    Allogeneic myeloablative haematopoietic stem cell transplantation (HSCT) is challenged by severe adverse events, as cytotoxic effects of the conditioning may result in systemic inflammation, leaky epithelial barriers and organ toxicities, contributing to treatment-related morbidity and mortality...... SDS decrease in IGF-1 (95% CI: 1.45-16.67), P=0.011 and OR=5.00 (1.37-20.00), P=0.015, respectively). Furthermore, low pre-transplant levels of IGF-1 and IGFBP-3 were associated with increased fluid retention during the first 21 days post transplant (OR=7.69 (95% CI: 1.59-33.33), P=0.012, and OR=2...

  8. Sinusoidal 50-Hz magnetic fields depress rat pineal NAT activity and serum melatonin. Role of duration and intensity of exposure.

    Science.gov (United States)

    Selmaoui, B; Touitou, Y

    1995-01-01

    The purpose of this study was to determine whether the exposure to a 50-Hz sinusoidal magnetic field could influence serum melatonin concentration and pineal enzymes activities in rats. The effects of both duration and intensity of exposure were also looked at. Two groups of Wistar male rats were exposed to 50-Hz magnetic fields of either 1, 10 or 100 microT. The first group was exposed for 12 hours and the second for 30 days (18 hours per day). During this time the animals were kept under a standard 12:12 light: dark cycle with a temperature of 25 degrees C and a relative humidity of 45 to 50%. Control (Sham-exposed) animals were kept in a similar environment but without exposure to a magnetic field. The animals were sacrificed under red dim light. Serum melatonin concentration and pineal N-acetyltransferase (NAT) and hydroxyindole-O-methyltransferase (HIOMT) activities were studied. Long-term exposure to a magnetic field (10 and 100 microT) significantly depressed the nocturne peak of serum melatonin concentration and pineal NAT activity whereas no effect was observed on HIOMT activity. Short-term exposure depressed both pineal NAT activity and nocturnal serum melatonin concentration but only with the highest intensity used (100 microT). Our results suggest that sinusoidal magnetic fields alter the production of melatonin through an inhibition of pineal NAT activity. Both duration and intensity of exposure play an important role in this effect. This work shows that, 1) sinusoidal magnetic field depresses NAT activity as static magnetic field does whereas HIOMT activity remains unaltered whatever the type of experiment and the intensity used, 2) the effect observed is related to both the duration of exposure and the intensity of magnetic fields, 3) the sensitivity threshold to magnetic fields vary with the duration of exposure which strongly suggests a cumulative effect of sinusoidal magnetic fields on pineal function.

  9. Large right ventricular sinusoids in an infant with aorta-left ventricular tunnel and proximal right coronary artery atresia.

    Science.gov (United States)

    Chen, Peter C; Spinner, Joseph A; Heinle, Jeffrey S

    2018-04-16

    We report a 1-month-old infant diagnosed with an aorta-left ventricular tunnel, ventricular septal defect, and right coronary atresia with right ventricular sinusoids. The patient's anatomy and physiology did not indicate right-ventricular-dependent coronary circulation, and therefore right ventricular decompression could be performed without compromising coronary perfusion during surgical correction. A detailed understanding of the coronary anatomy is critical in managing this defect when coronary anomalies are present.

  10. Sinusoidal oscillators with lower gain requirements at higher frequencies based on an explicit tanh(x) nonlinearity

    KAUST Repository

    Elwakil, Ahmed S.

    2009-04-28

    Two novel sinusoidal oscillator structures with an explicit tanh(x) nonlinearity are proposed. The oscillators have the attractive feature: the higher the operating frequency, the lower the necessary gain required to start oscillations. A nonlinear model for the two oscillators is derived and verified numerically. Spice simulations using AMS BiCMOS 0.35 μ model parameters and experimental results are shown. Copyright © 2009 John Wiley & Sons, Ltd.

  11. Turbine blade squealer tip rail with fence members

    Science.gov (United States)

    Little, David A

    2012-11-20

    A turbine blade includes an airfoil, a blade tip section, a squealer tip rail, and a plurality of chordally spaced fence members. The blade tip section includes a blade tip floor located at an end of the airfoil distal from the root. The blade tip floor includes a pressure side and a suction side joined together at chordally spaced apart leading and trailing edges of the airfoil. The squealer tip rail extends radially outwardly from the blade tip floor adjacent to the suction side and extends from a first location adjacent to the airfoil trailing edge to a second location adjacent to the airfoil leading edge. The fence members are located between the airfoil leading and trailing edges and extend radially outwardly from the blade tip floor and axially from the squealer tip rail toward the pressure side.

  12. Three-Orthogonal-Direction Stress Mapping around a Fatigue-Crack Tip Using Neutron Diffraction

    Science.gov (United States)

    Huang, E.-Wen; Lee, Soo Yeol; Woo, Wanchuck; Lee, Kuan-Wei

    2012-08-01

    Quantitative determination of the stress fields around the crack tip is a challenging and important subject to understand the fatigue crack-growth mechanism. In the current study, we measured the distribution of residual stresses and the evolution of the stress fields around a fatigue crack tip subjected to the constant-amplitude cyclic loading in a 304L stainless steel compact-tension (CT) specimen. The three orthogonal stress components ( i.e., crack growth, crack opening, and through thickness) of the CT specimen were determined as a function of distance from the crack tip with 1-mm spatial resolution along the crack-propagation direction. In-situ neutron-diffraction results show that the enlarged tensile stresses were developed during loading along the through-thickness direction at a localized volume close to the crack tip, resulting in the lattice expansion in all three orthogonal directions during P max. The current study suggests that the atypical plane strainlike behavior observed at the midthickness position might be the reason for the mechanism of the faster crack-growth rate inside the interior than that near the surface.

  13. Dielectrophoretic positioning of single nanoparticles on atomic force microscope tips for tip-enhanced Raman spectroscopy.

    Science.gov (United States)

    Leiterer, Christian; Deckert-Gaudig, Tanja; Singh, Prabha; Wirth, Janina; Deckert, Volker; Fritzsche, Wolfgang

    2015-05-01

    Tip-enhanced Raman spectroscopy, a combination of Raman spectroscopy and scanning probe microscopy, is a powerful technique to detect the vibrational fingerprint of molecules at the nanometer scale. A metal nanoparticle at the apex of an atomic force microscope tip leads to a large enhancement of the electromagnetic field when illuminated with an appropriate wavelength, resulting in an increased Raman signal. A controlled positioning of individual nanoparticles at the tip would improve the reproducibility of the probes and is quite demanding due to usually serial and labor-intensive approaches. In contrast to commonly used submicron manipulation techniques, dielectrophoresis allows a parallel and scalable production, and provides a novel approach toward reproducible and at the same time affordable tip-enhanced Raman spectroscopy tips. We demonstrate the successful positioning of an individual plasmonic nanoparticle on a commercial atomic force microscope tip by dielectrophoresis followed by experimental proof of the Raman signal enhancing capabilities of such tips. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Tip off the HAT- Epigenetic control of learning and memory by Drosophila Tip60.

    Science.gov (United States)

    Xu, Songjun; Elefant, Felice

    2015-01-01

    Disruption of epigenetic gene control mechanisms involving histone acetylation in the brain causes cognitive impairment, a debilitating hallmark of most neurodegenerative disorders. Histone acetylation regulates cognitive gene expression via chromatin packaging control in neurons. Unfortunately, the histone acetyltransferases (HATs) that generate such neural epigenetic signatures and their mechanisms of action remain unclear. Our recent findings provide insight into this question by demonstrating that Tip60 HAT action is critical for morphology and function of the mushroom body (MB), the learning and memory center in the Drosophila brain. We show that Tip60 is robustly produced in MB Kenyon cells and extending axonal lobes and that targeted MB Tip60 HAT loss results in axonal outgrowth disruption. Functional consequences of loss and gain of Tip60 HAT levels in the MB are evidenced by defects in memory. Tip60 ChIP-Seq analysis reveals enrichment for genes that function in cognitive processes and accordingly, key genes representing these pathways are misregulated in the Tip60 HAT mutant fly brain. Remarkably, increasing levels of Tip60 in the MB rescues learning and memory deficits resulting from Alzheimer's disease associated amyloid precursor protein (APP) induced neurodegeneration. Our studies highlight the potential of HAT activators as a therapeutic option for cognitive disorders.

  15. Design of Helical Capacitance Sensor for Holdup Measurement in Two-Phase Stratified Flow: A Sinusoidal Function Approach.

    Science.gov (United States)

    Lim, Lam Ghai; Pao, William K S; Hamid, Nor Hisham; Tang, Tong Boon

    2016-07-04

    A 360° twisted helical capacitance sensor was developed for holdup measurement in horizontal two-phase stratified flow. Instead of suppressing nonlinear response, the sensor was optimized in such a way that a 'sine-like' function was displayed on top of the linear function. This concept of design had been implemented and verified in both software and hardware. A good agreement was achieved between the finite element model of proposed design and the approximation model (pure sinusoidal function), with a maximum difference of ±1.2%. In addition, the design parameters of the sensor were analysed and investigated. It was found that the error in symmetry of the sinusoidal function could be minimized by adjusting the pitch of helix. The experiments of air-water and oil-water stratified flows were carried out and validated the sinusoidal relationship with a maximum difference of ±1.2% and ±1.3% for the range of water holdup from 0.15 to 0.85. The proposed design concept therefore may pose a promising alternative for the optimization of capacitance sensor design.

  16. Design of Helical Capacitance Sensor for Holdup Measurement in Two-Phase Stratified Flow: A Sinusoidal Function Approach

    Directory of Open Access Journals (Sweden)

    Lam Ghai Lim

    2016-07-01

    Full Text Available A 360° twisted helical capacitance sensor was developed for holdup measurement in horizontal two-phase stratified flow. Instead of suppressing nonlinear response, the sensor was optimized in such a way that a ‘sine-like’ function was displayed on top of the linear function. This concept of design had been implemented and verified in both software and hardware. A good agreement was achieved between the finite element model of proposed design and the approximation model (pure sinusoidal function, with a maximum difference of ±1.2%. In addition, the design parameters of the sensor were analysed and investigated. It was found that the error in symmetry of the sinusoidal function could be minimized by adjusting the pitch of helix. The experiments of air-water and oil-water stratified flows were carried out and validated the sinusoidal relationship with a maximum difference of ±1.2% and ±1.3% for the range of water holdup from 0.15 to 0.85. The proposed design concept therefore may pose a promising alternative for the optimization of capacitance sensor design.

  17. Design of Helical Capacitance Sensor for Holdup Measurement in Two-Phase Stratified Flow: A Sinusoidal Function Approach

    Science.gov (United States)

    Lim, Lam Ghai; Pao, William K. S.; Hamid, Nor Hisham; Tang, Tong Boon

    2016-01-01

    A 360° twisted helical capacitance sensor was developed for holdup measurement in horizontal two-phase stratified flow. Instead of suppressing nonlinear response, the sensor was optimized in such a way that a ‘sine-like’ function was displayed on top of the linear function. This concept of design had been implemented and verified in both software and hardware. A good agreement was achieved between the finite element model of proposed design and the approximation model (pure sinusoidal function), with a maximum difference of ±1.2%. In addition, the design parameters of the sensor were analysed and investigated. It was found that the error in symmetry of the sinusoidal function could be minimized by adjusting the pitch of helix. The experiments of air-water and oil-water stratified flows were carried out and validated the sinusoidal relationship with a maximum difference of ±1.2% and ±1.3% for the range of water holdup from 0.15 to 0.85. The proposed design concept therefore may pose a promising alternative for the optimization of capacitance sensor design. PMID:27384567

  18. Cooperative effect of monoclinic distortion and sinusoidal modulation in the martensitic structure of Ni2FeGa

    International Nuclear Information System (INIS)

    Lu, J.B.; Yang, H.X.; Tian, H.F.; Zeng, L.J.; Ma, C.; Feng, L.; Wu, G.H.; Li, J.Q.; Jansen, J.

    2010-01-01

    The structural features of the '5M' martensitic phase in Ni 2 FeGa alloys have been determined by electron diffraction using the multi-slice least-squares (MSLS) method. The results demonstrate that the '5M' phase contains an evident cooperative effect of monoclinic distortion and sinusoidal modulation along the [110] c direction. Theoretical simulations based on our refined data suggest that the '5M' martensitic phase observed in Ni-Fe-Ga and Ni-Mn-Ga has visible common behaviors in both stacking sequence and local structural distortion. Considering the cooperative effect of monoclinic distortion and sinusoidal modulation, we demonstrate that the '7M' martensitic phase could adopt two equivalent structural phases corresponding with the stacking sequences of (43 - ) 2 and (52 - ) 2 , respectively. - Graphical abstract: The structural model of the '5M' Ni 2 FeGa martensite viewed along the [001] c (i.e. [010] m ) zone axis, demonstrating the cooperative effect of monoclinic distortion and sinusoidal modulation along the [110] c direction.

  19. Sinusoidal echo-planar imaging with parallel acquisition technique for reduced acoustic noise in auditory fMRI.

    Science.gov (United States)

    Zapp, Jascha; Schmitter, Sebastian; Schad, Lothar R

    2012-09-01

    To extend the parameter restrictions of a silent echo-planar imaging (sEPI) sequence using sinusoidal readout (RO) gradients, in particular with increased spatial resolution. The sound pressure level (SPL) of the most feasible configurations is compared to conventional EPI having trapezoidal RO gradients. We enhanced the sEPI sequence by integrating a parallel acquisition technique (PAT) on a 3 T magnetic resonance imaging (MRI) system. The SPL was measured for matrix sizes of 64 × 64 and 128 × 128 pixels, without and with PAT (R = 2). The signal-to-noise ratio (SNR) was examined for both sinusoidal and trapezoidal RO gradients. Compared to EPI PAT, the SPL could be reduced by up to 11.1 dB and 5.1 dB for matrix sizes of 64 × 64 and 128 × 128 pixels, respectively. The SNR of sinusoidal RO gradients is lower by a factor of 0.96 on average compared to trapezoidal RO gradients. The sEPI PAT sequence allows for 1) increased resolution, 2) expanded RO frequency range toward lower frequencies, which is in general beneficial for SPL, or 3) shortened TE, TR, and RO train length. At the same time, it generates lower SPL compared to conventional EPI for a wide range of RO frequencies while having the same imaging parameters. Copyright © 2012 Wiley Periodicals, Inc.

  20. Dynamical pattern formation in a low-concentration magnetorheological fluid under two orthogonal sinusoidal fields

    International Nuclear Information System (INIS)

    Yépez, L.D.; Carrillo, J.L.; Donado, F.; Sausedo-Solorio, J.M.; Miranda-Romagnoli, P.

    2016-01-01

    The dynamical pattern formation of clusters of magnetic particles in a low-concentration magnetorheological fluid, under the influence of a superposition of two perpendicular sinusoidal fields, is studied experimentally. By varying the frequency and phase shift of the perpendicular fields, this configuration enables us to experimentally analyze a wide range of field configurations, including the case of a pure rotating field and the case of an oscillating unidirectional field. The fields are applied parallel to the horizontal plane where the fluid lies or in the vertical plane. For fields applied in the horizontal plane, we observed that, when the ratio of the frequencies increases, the average cluster size exhibits a kind of periodic resonances. When the phase shift between the fields is varied, the average chain length reaches maximal values for the cases of the rotating field and the unidirectional case. We analyze and discuss these results in terms of a weighted average of the time-dependent Mason number. In the case of a rotating field on the vertical plane, we also observe that the competition between the magnetic and the viscous forces determines the average cluster size. We show that this configuration generates a series of physically meaningful self-organization of clusters and transport phenomena. - Highlights: • A weighted average of the time-dependent Mason number is proposed. • The self-propelling clusters appear when a vertical rotating magnetic field is applied. • The largest average chain lengths are reached when frequencies are multiples one another. • Rotating and unidirectional alternating fields produce the largest average chain length values.

  1. Dynamical pattern formation in a low-concentration magnetorheological fluid under two orthogonal sinusoidal fields

    Energy Technology Data Exchange (ETDEWEB)

    Yépez, L.D.; Carrillo, J.L. [Instituto de Física de la Universidad Autónoma de Puebla, Ciudad Universitaria, Edif. 110 A, Puebla 72570 (Mexico); Donado, F.; Sausedo-Solorio, J.M.; Miranda-Romagnoli, P. [Instituto de Ciencias Básicas e Ingeniería Universidad Autónoma del Estado de Hidalgo, Pachuca 42090, Pachuca (Mexico)

    2016-06-15

    The dynamical pattern formation of clusters of magnetic particles in a low-concentration magnetorheological fluid, under the influence of a superposition of two perpendicular sinusoidal fields, is studied experimentally. By varying the frequency and phase shift of the perpendicular fields, this configuration enables us to experimentally analyze a wide range of field configurations, including the case of a pure rotating field and the case of an oscillating unidirectional field. The fields are applied parallel to the horizontal plane where the fluid lies or in the vertical plane. For fields applied in the horizontal plane, we observed that, when the ratio of the frequencies increases, the average cluster size exhibits a kind of periodic resonances. When the phase shift between the fields is varied, the average chain length reaches maximal values for the cases of the rotating field and the unidirectional case. We analyze and discuss these results in terms of a weighted average of the time-dependent Mason number. In the case of a rotating field on the vertical plane, we also observe that the competition between the magnetic and the viscous forces determines the average cluster size. We show that this configuration generates a series of physically meaningful self-organization of clusters and transport phenomena. - Highlights: • A weighted average of the time-dependent Mason number is proposed. • The self-propelling clusters appear when a vertical rotating magnetic field is applied. • The largest average chain lengths are reached when frequencies are multiples one another. • Rotating and unidirectional alternating fields produce the largest average chain length values.

  2. First evidence of pyrrolizidine alkaloid N-oxide-induced hepatic sinusoidal obstruction syndrome in humans.

    Science.gov (United States)

    Yang, Mengbi; Ruan, Jianqing; Gao, Hong; Li, Na; Ma, Jiang; Xue, Junyi; Ye, Yang; Fu, Peter Pi-Cheng; Wang, Jiyao; Lin, Ge

    2017-12-01

    Pyrrolizidine alkaloids (PAs) are among the most potent phytotoxins widely distributed in plant species around the world. PA is one of the major causes responsible for the development of hepatic sinusoidal obstruction syndrome (HSOS) and exerts hepatotoxicity via metabolic activation to form the reactive metabolites, which bind with cellular proteins to generate pyrrole-protein adducts, leading to hepatotoxicity. PA N-oxides coexist with their corresponding PAs in plants with varied quantities, sometimes even higher than that of PAs, but the toxicity of PA N-oxides remains unclear. The current study unequivocally identified PA N-oxides as the sole or predominant form of PAs in 18 Gynura segetum herbal samples ingested by patients with liver damage. For the first time, PA N-oxides were recorded to induce HSOS in human. PA N-oxide-induced hepatotoxicity was further confirmed on mice orally dosed of herbal extract containing 170 μmol PA N-oxides/kg/day, with its hepatotoxicity similar to but potency much lower than the corresponding PAs. Furthermore, toxicokinetic study after a single oral dose of senecionine N-oxide (55 μmol/kg) on rats revealed the toxic mechanism that PA N-oxides induced hepatotoxicity via their biotransformation to the corresponding PAs followed by the metabolic activation to form pyrrole-protein adducts. The remarkable differences in toxicokinetic profiles of PAs and PA N-oxides were found and attributed to their significantly different hepatotoxic potency. The findings of PA N-oxide-induced hepatotoxicity in humans and rodents suggested that the contents of both PAs and PA N-oxides present in herbs and foods should be regulated and controlled in use.

  3. Removing damped sinusoidal vibrations in adaptive optics systems using a DFT-based estimation method

    Science.gov (United States)

    Kania, Dariusz

    2017-06-01

    The problem of a vibrations rejection in adaptive optics systems is still present in publications. These undesirable signals emerge because of shaking the system structure, the tracking process, etc., and they usually are damped sinusoidal signals. There are some mechanical solutions to reduce the signals but they are not very effective. One of software solutions are very popular adaptive methods. An AVC (Adaptive Vibration Cancellation) method has been presented and developed in recent years. The method is based on the estimation of three vibrations parameters and values of frequency, amplitude and phase are essential to produce and adjust a proper signal to reduce or eliminate vibrations signals. This paper presents a fast (below 10 ms) and accurate estimation method of frequency, amplitude and phase of a multifrequency signal that can be used in the AVC method to increase the AO system performance. The method accuracy depends on several parameters: CiR - number of signal periods in a measurement window, N - number of samples in the FFT procedure, H - time window order, SNR, THD, b - number of A/D converter bits in a real time system, γ - the damping ratio of the tested signal, φ - the phase of the tested signal. Systematic errors increase when N, CiR, H decrease and when γ increases. The value of systematic error for γ = 0.1%, CiR = 1.1 and N = 32 is approximately 10^-4 Hz/Hz. This paper focuses on systematic errors of and effect of the signal phase and values of γ on the results.

  4. Effects of δ-hydride precipitation at a crack tip on crack propagation in delayed hydride cracking of Zircaloy-2

    Science.gov (United States)

    Kubo, T.; Kobayashi, Y.

    2013-08-01

    Delayed hydride cracking (DHC) of Zircaloy-2 is one possible mechanism for the failure of boiling water reactor fuel rods in ramp tests at high burnup. Analyses were made for hydrogen diffusion around a crack tip to estimate the crack velocity of DHC in zirconium alloys, placing importance on effects of precipitation of δ-hydride. The stress distribution around the crack tip is significantly altered by precipitation of hydride, which was strictly analyzed using a finite element computer code. Then, stress-driven hydrogen diffusion under the altered stress distribution was analyzed by a differential method. Overlapping of external stress and hydride precipitation at a crack tip induces two stress peaks; one at a crack tip and the other at the front end of the hydride precipitate. Since the latter is larger than the former, more hydrogen diffuses to the front end of the hydride precipitate, thereby accelerating hydride growth compared with that in the absence of the hydride. These results indicated that, after hydride was formed in front of the crack tip, it grew almost steadily accompanying the interaction of hydrogen diffusion, hydride growth and the stress alteration by hydride precipitation. Finally, crack velocity was estimated from the calculated hydrogen flux into the crack tip as a function of temperature, stress intensity factor and material strength. There was qualitatively good agreement between calculation results and experimental data. The stress distribution around the crack tip is significantly altered by precipitation of hydride. Overlapping of external stress and hydride precipitation at a crack tip induces two stress peaks; one at a crack tip and the other at the front end of the hydride precipitate. Since the latter is larger than the former, more hydrogen diffuses to the front end of the hydride precipitate, thereby accelerating hydride growth compared with that in the absence of the hydride. These results indicated that, after hydride was formed

  5. The kinesin-4 protein Kif7 regulates mammalian Hedgehog signalling by organizing the cilium tip compartment.

    Science.gov (United States)

    He, Mu; Subramanian, Radhika; Bangs, Fiona; Omelchenko, Tatiana; Liem, Karel F; Kapoor, Tarun M; Anderson, Kathryn V

    2014-07-01

    Mammalian Hedgehog (Hh) signal transduction requires a primary cilium, a microtubule-based organelle, and the Gli-Sufu complexes that mediate Hh signalling, which are enriched at cilia tips. Kif7, a kinesin-4 family protein, is a conserved regulator of the Hh signalling pathway and a human ciliopathy protein. Here we show that Kif7 localizes to the cilium tip, the site of microtubule plus ends, where it limits cilium length and controls cilium structure. Purified recombinant Kif7 binds the plus ends of growing microtubules in vitro, where it reduces the rate of microtubule growth and increases the frequency of microtubule catastrophe. Kif7 is not required for normal intraflagellar transport or for trafficking of Hh pathway proteins into cilia. Instead, a central function of Kif7 in the mammalian Hh pathway is to control cilium architecture and to create a single cilium tip compartment, where Gli-Sufu activity can be correctly regulated.

  6. Optical fiber tips for biological applications: From light confinement, biosensing to bioparticles manipulation.

    Science.gov (United States)

    Paiva, Joana S; Jorge, Pedro A S; Rosa, Carla C; Cunha, João P S

    2018-05-01

    The tip of an optical fiber has been considered an attractive platform in Biology. The simple cleaved end of an optical fiber can be machined, patterned and/or functionalized, acquiring unique properties enabling the exploitation of novel optical phenomena. Prompted by the constant need to measure and manipulate nanoparticles, the invention of the Scanning Near-field Optical Microscopy (SNOM) triggered the optimization and development of novel fiber tip microfabrication methods. In fact, the fiber tip was soon considered a key element in SNOM by confining light to sufficiently small extensions, challenging the diffraction limit. As result and in consequence of the newly proposed "Lab On Tip" concept, several geometries of fiber tips were applied in three main fields: imaging (in Microscopy/Spectroscopy), biosensors and micromanipulation (Optical Fiber Tweezers, OFTs). These are able to exert forces on microparticles, trap and manipulate them for relevant applications, as biomolecules mechanical study or protein aggregates unfolding. This review presents an overview of the main achievements, most impactful studies and limitations of fiber tip-based configurations within the above three fields, along the past 10 years. OFTs could be in future a valuable tool for studying several cellular phenomena such as neurodegeneration caused by abnormal protein fibrils or manipulating organelles within cells. This could contribute to understand the mechanisms of some diseases or biophenomena, as the axonal growth in neurons. To the best of our knowledge, no other review article has so far provided such a broad view. Despite of the limitations, fiber tips have key roles in Biology/Medicine. Copyright © 2018 Elsevier B.V. All rights reserved.

  7. Discrete modelling of ductile crack growth by void growth to coalescence

    DEFF Research Database (Denmark)

    Tvergaard, Viggo

    2007-01-01

    of the ligaments between the crack-tip and a void or between voids involves the development of very large strains, which are included in the model by using remeshing at several stages of the plastic deformation. The material is here described by standard isotropic hardening Mises theory. For a very small void......Ductile crack growth is analyzed by discrete representation of the voids growing near a blunting crack-tip. Coalescence of the nearest void with the crack-tip is modeled, followed by the subsequent coalescence of other discretely represented voids with the newly formed crack-tip. Necking...... volume fraction the crack-tip tends to interact with one void at a time, while larger void volume fractions lead to simultaneous interaction of multiple voids on the plane ahead of the crack-tip. In some cases a change from one of these mechanisms to the other is seen during growth through the many voids...

  8. Tip Saves Energy, Money for Pennsylvania Plant

    Science.gov (United States)

    A wastewater treatment plant in Berks County, Pennsylvania is saving nearly $45,000 a year and reducing hundreds of metric tons of greenhouse gases since employing an energy conservation tip offered by the Water Protection Division in EPA’s R3 and PADEP.

  9. International Travel: Tips for Staying Healthy

    Science.gov (United States)

    ... Conditions Prevention and Wellness Staying Healthy Healthy Living Travel Occupational Health First Aid and Injury Prevention Crisis ... MoreDepression in Children and TeensRead MoreBMI Calculator Air Travel Health TipsTexting and DrivingTravel Needs for SeniorsFood PoisoningAcute ...

  10. Barbecue Basics: Tips to Prevent Foodborne Illness

    Medline Plus

    Full Text Available ... Español Search FDA Submit search Popular Content Home Food Drugs Medical Devices Radiation-Emitting Products Vaccines, ... Biologics Animal & Veterinary Cosmetics Tobacco Products For Consumers Home For Consumers Consumer Updates Barbecue Basics: Tips to ...

  11. What Do You Mean, 'Tipping Point'?

    NARCIS (Netherlands)

    Nes, van E.H.; Shojaei Arani, M.; Staal, A.; Bolt, van der B.; Flores, Bernardo M.; Bathiany, S.; Scheffer, M.

    2016-01-01

    Over the past 10 years the use of the term ‘tipping point’ in the scientific literature has exploded. It was originally used loosely as a metaphor for the phenomenon that, beyond a certain threshold, runaway change propels a system to a new state. Although several specific mathematical definitions

  12. Direct calculation of wind turbine tip loss

    DEFF Research Database (Denmark)

    Wood, D.H.; Okulov, Valery; Bhattacharjee, D.

    2016-01-01

    . We develop three methods for the direct calculation of the tip loss. The first is the computationally expensive calculation of the velocities induced by the helicoidal wake which requires the evaluation of infinite sums of products of Bessel functions. The second uses the asymptotic evaluation...

  13. The Tipping Points of Technology Development

    Directory of Open Access Journals (Sweden)

    Tauno Kekäle

    2014-07-01

    Full Text Available The tipping point, the decisive point in time in the competition between old and new, is an interesting phenomenon in physics of today. This aspect in technology acceptance is connected to many business decisions such as technology investments, product releases, resource allocation, sales forecasts and, ultimately, affects the profitability and even survival of a company. The tipping point itself is based on many stochastic and dynamic variables, and the process may at least partly be described as path-dependent. This paper analyses the tipping point from three aspects: (1 product performance, (2 features of the market and infrastructure (including related technologies and human network externalities, and (3 actions of the incumbents (including customer lock-in, systems lock-in, and sustaining innovation. The paper is based on the Bass s-curve idea and the technology trajectory concept proposed by Dosi. Three illustrative cases are presented to make the point of the multiple factors affecting technology acceptance and, thus, the tipping point. The paper also suggests outlines for further research in field of computer simulation.

  14. Tips for Airline Travelers with Sjogren's Syndrome

    Science.gov (United States)

    Tips for Airline Travelers with Sjögren’s Syndrome For more information on Sjogren's syndrome, visit the SSF Web site at www.sjogrens. ... org for more information on Sjögren’s syndrome. New airline rules can have a profound effect on those ...

  15. Final Technical Report: Electrohydrodynamic Tip Streaming

    Energy Technology Data Exchange (ETDEWEB)

    Basaran, Osman [Purdue Univ., West Lafayette, IN (United States)

    2016-01-06

    When subjected to strong electric fields, liquid drops and films form conical tips and emit thin jets from their tips. Such electrodydrodynamic (EDH) tip streaming or cone-jetting phenomena, which are sometimes referred to as electrospraying, occur widely in nature, e.g., in ejection of streams of small charged drops from pointed tips of raindrops in thunderclouds, and technology, e.g., in electrospray mass spectrometry or electric field-driven solvent extraction. More recently, EHD cone-jetting has emerged as a powerful technique for direct printing of solar cells, micro- and nano- particle production, and microencapsulation for controlled release. In many of the aforementioned situations, of equal importance to the processes by which one drop disintegrates to form several drops are those by which (a) two drops come together and coalesce and (b) two drops are coupled to form a double droplet system (DDS) or a capillary switch (CS). the main objective of this research program is to advance through simulation, theory, and experiment the breakup, coalescence, and oscillatory dynamics of single and pairs of charged as well as uncharged drops.

  16. Tip cells: master regulators of tubulogenesis?

    Science.gov (United States)

    Weavers, Helen; Skaer, Helen

    2014-07-01

    The normal development of an organ depends on the coordinated regulation of multiple cell activities. Focusing on tubulogenesis, we review the role of specialised cells or groups of cells that are selected from within tissue primordia and differentiate at the outgrowing tips or leading edge of developing tubules. Tip or leading cells develop distinctive patterns of gene expression that enable them to act both as sensors and transmitters of intercellular signalling. This enables them to explore the environment, respond to both tissue intrinsic signals and extrinsic cues from surrounding tissues and to regulate the behaviour of their neighbours, including the setting of cell fate, patterning cell division, inducing polarity and promoting cell movement and cell rearrangements by neighbour exchange. Tip cells are also able to transmit mechanical tension to promote tissue remodelling and, by interacting with the extracellular matrix, they can dictate migratory pathways and organ shape. Where separate tubular structures fuse to form networks, as in the airways of insects or the vascular system of vertebrates, specialised fusion tip cells act to interconnect disparate elements of the developing network. Finally, we consider their importance in the maturation of mature physiological function and in the development of disease. Copyright © 2014 The Authors. Published by Elsevier Ltd.. All rights reserved.

  17. Study of tip loss corrections using CFD rotor computations

    DEFF Research Database (Denmark)

    Shen, Wen Zhong; Zhu, Wei Jun; Sørensen, Jens Nørkær

    2014-01-01

    Tip loss correction is known to play an important role for engineering prediction of wind turbine performance. There are two different types of tip loss corrections: tip corrections on momentum theory and tip corrections on airfoil data. In this paper, we study the latter using detailed CFD compu...... and compared with CFD results for the NordTank 500 kW turbine and the NREL 5 MW turbine. Comparisons show that BEM with the new tip loss function can predict correctly the loading near the blade tip.......Tip loss correction is known to play an important role for engineering prediction of wind turbine performance. There are two different types of tip loss corrections: tip corrections on momentum theory and tip corrections on airfoil data. In this paper, we study the latter using detailed CFD...... computations for wind turbines with sharp tip. Using the technique of determination of angle of attack and the CFD results for a NordTank 500 kW rotor, airfoil data are extracted and a new tip loss function on airfoil data is derived. To validate, BEM computations with the new tip loss function are carried out...

  18. Influence of the Periodicity of Sinusoidal Boundary Condition on the Unsteady Mixed Convection within a Square Enclosure Using an Ag–Water Nanofluid

    Directory of Open Access Journals (Sweden)

    Azharul Karim

    2017-12-01

    Full Text Available A numerical study of the unsteady mixed convection heat transfer characteristics of an Ag–water nanofluid confined within a square shape lid-driven cavity has been carried out. The Galerkin weighted residual of the finite element method has been employed to investigate the effects of the periodicity of sinusoidal boundary condition for a wide range of Grashof numbers (Gr (105 to 107 with the parametric variation of sinusoidal even and odd frequency, N, from 1 to 6 at different instants (for τ = 0.1 and 1. It has been observed that both the Grashof number and the sinusoidal even and odd frequency have a significant influence on the streamlines and isotherms inside the cavity. The heat transfer rate enhanced by 90% from the heated surface as the Grashof number (Gr increased from 105 to 107 at sinusoidal frequency N = 1 and τ = 1.

  19. Tips for Good Health in Later Life: For Older Women

    Science.gov (United States)

    ... Geriatrics Osteoporosis Prevention Related Documents PDF Tips for Good Health in Later Life: For Older Women Download Join our e-newsletter! Resources Tips for Good Health in Later Life: For Older Women Tools ...

  20. Tips to Make Fast Food Friendlier for Kids

    Science.gov (United States)

    ... Workplace Food and Beverage Toolkit Tips to Make Fast Food Friendlier for Kids Updated:Feb 6,2017 Finding ... reheated or eaten on the road. But when fast food is your only option, try these tips to ...

  1. Cytology of root tips of Dioscoreophyllum cumminsii (STAPF) diel ...

    African Journals Online (AJOL)

    , University of Nigeria Nsukka. Root tips for the chromosome work were obtained from three sources: runners originating from main vine; sprouting pieces of tubers and redifferentiated root tips from callus. The results showed that normal ...

  2. Effect of Stress on Corrosion at Crack Tip on Pipeline Steel in a Near-Neutral pH Solution

    Science.gov (United States)

    Yang, Yao; Cheng, Y. Frank

    2016-11-01

    In this work, the local corrosion at crack tip on an API 5L X46 pipeline steel specimens was investigated under various applied loads in a near-neutral pH solution. Electrochemical measurements, including potentiodynamic polarization and electrochemical impedance spectroscopy, combined with micro-electrochemical technique and surface characterization, were conducted to investigate the effect of stress on local anodic solution of the steel at the crack tip. The stress corrosion cracking of the steel was dominated by an anodic dissolution mechanism, while the effect of hydrogen was negligible. The applied load (stress) increased the corrosion rate at the crack tip, contributing to crack propagation. The deposit of corrosion products at the crack tip could protect somewhat from further corrosion. At sufficiently large applied loads such as 740 N in the work, it was possible to generate separated cathode and anode, further accelerating the crack growth.

  3. Expression of tomato SlTIP2;2 enhances the tolerance to salt stress in the transgenic Arabidopsis and interacts with target proteins.

    Science.gov (United States)

    Xin, Shichao; Yu, Guohong; Sun, Linlin; Qiang, Xiaojing; Xu, Na; Cheng, Xianguo

    2014-11-01

    Three independent transgenic Arabidopsis lines expressing SlTIP2;2 from Solanum lycopersicum L. cv. Lichun under the control of its endogenous promoter were used to analyze the expression of SlTIP2;2 and the salt stress tolerance under NaCl concentration gradient treatment. The expression patterns of SlTIP2;2 were shown to be tissue-specific and NaCl dose-dependent under salt stress. SlTIP2;2-transformed Arabidopsis plants exhibited enhanced salt stress tolerance, and the physiological parameters suggested that SlTIP2;2 has close links with the ion homeostasis and antioxidant enzymes activities in salt-stressed transgenic Arabidopsis. Moreover, SlTIP2;2 expression significantly affected the Na(+) and K(+) fluxes from the root meristematic zones and resulted in remarkable changes in the morphology of the pith ray cells in the inflorescence stems of transgenic Arabidopsis. Based on the yeast growth assay, β-galactosidase activity testing and bimolecular fluorescence complementation, SlTIP1;1, SlTIP2;1 and an UDP-galactose transporter were confirmed to interact with SlTIP2;2, which may greatly broaden our understanding of the physiological functions of aquaporins.

  4. Tracking Blade Tip Vortices for Numerical Flow Simulations of Hovering Rotorcraft

    Science.gov (United States)

    Kao, David L.

    2016-01-01

    Blade tip vortices generated by a helicopter rotor blade are a major source of rotor noise and airframe vibration. This occurs when a vortex passes closely by, and interacts with, a rotor blade. The accurate prediction of Blade Vortex Interaction (BVI) continues to be a challenge for Computational Fluid Dynamics (CFD). Though considerable research has been devoted to BVI noise reduction and experimental techniques for measuring the blade tip vortices in a wind tunnel, there are only a handful of post-processing tools available for extracting vortex core lines from CFD simulation data. In order to calculate the vortex core radius, most of these tools require the user to manually select a vortex core to perform the calculation. Furthermore, none of them provide the capability to track the growth of a vortex core, which is a measure of how quickly the vortex diffuses over time. This paper introduces an automated approach for tracking the core growth of a blade tip vortex from CFD simulations of rotorcraft in hover. The proposed approach offers an effective method for the quantification and visualization of blade tip vortices in helicopter rotor wakes. Keywords: vortex core, feature extraction, CFD, numerical flow visualization

  5. 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.

  6. Mechanisms for enlarging lesion size during irrigated tip radiofrequency ablation

    DEFF Research Database (Denmark)

    Petersen, Helen Høgh; Roman-Gonzalez, Javier; Johnson, Susan B

    2004-01-01

    INTRODUCTION: Irrigated tip radiofrequency ablation of cardiac arrhythmias was developed to increase the size of the radiofrequency-induced lesion, since cooling of the electrode tip allows use of higher power settings. The purpose of this study was to determine if the increased lesion size during......(3) (P radiofrequency irrigated-tip ablation is that higher power levels can be used...

  7. Modular design of AFM probe with sputtered silicon tip

    DEFF Research Database (Denmark)

    Rasmussen, Peter; Thaysen, Jacob; Bouwstra, Siebe

    2001-01-01

    of the thin films constituting the cantilever. The AFM probe has an integrated tip made of a thick sputtered silicon layer, which is deposited after the probe has been defined and just before the cantilevers are released. The tips are so-called rocket tips made by reactive ion etching. We present probes...

  8. Twelve tips for facilitating Millennials' learning.

    Science.gov (United States)

    Roberts, David H; Newman, Lori R; Schwartzstein, Richard M

    2012-01-01

    The current, so-called "Millennial" generation of learners is frequently characterized as having deep understanding of, and appreciation for, technology and social connectedness. This generation of learners has also been molded by a unique set of cultural influences that are essential for medical educators to consider in all aspects of their teaching, including curriculum design, student assessment, and interactions between faculty and learners.  The following tips outline an approach to facilitating learning of our current generation of medical trainees.  The method is based on the available literature and the authors' experiences with Millennial Learners in medical training.  The 12 tips provide detailed approaches and specific strategies for understanding and engaging Millennial Learners and enhancing their learning.  With an increased understanding of the characteristics of the current generation of medical trainees, faculty will be better able to facilitate learning and optimize interactions with Millennial Learners.

  9. Reconstruction of nasal tip and columella.

    Science.gov (United States)

    Faris, Callum; Vuyk, Hade D

    2011-02-01

    Reconstruction of nasal tip and columella defects is demanding area with a range of reconstructive options, varying in complexity depending on requirements from simple skin grafting to multiple stage reconstruction with regional flaps. A framework is suggested to aid the reader in choice of reconstruction by classifying the defect based on size and the requirements of one to three layer (full thickness) reconstruction. Copyright © 2011 Elsevier Inc. All rights reserved.

  10. Oracle Apex reporting tips and tricks

    CERN Document Server

    Bara, George

    2013-01-01

    Take advantage of all the exciting Reporting features of Oracle Application Express 4.2. Designed for a hands-on approach, this book contains in-depth practical guidelines from George Bara, a well-known Oracle Apex expert and blogger. From Classic to Interactive Reports, Web Services and Pdf Printing, "Oracle Apex Reporting Tips & Tricks" is a must-have for all database developers that want to make the most out of the Oracle Apex reporting engine.

  11. Exodontia: tips and techniques for better outcomes.

    Science.gov (United States)

    Dym, Harry; Weiss, Adam

    2012-01-01

    This article reviews and highlights exodontia tips as well as new techniques to make simple and complex exodontia more predictable and efficient with improved patient outcomes. A discussion of a powered periotome that has been developed to aid in the atraumatic extraction of teeth and another new device, the piezosurgery, increasingly used for outpatient oral surgery procedures are included. Physics forceps, a new type of exodontia forceps, is also discussed in this article. Copyright © 2012 Elsevier Inc. All rights reserved.

  12. Dynamics of the Josephson multi-junction system with junctions characterized by non-sinusoidal current - phase relationship

    International Nuclear Information System (INIS)

    Abal'osheva, I.; Lewandowski, S.J.

    2004-01-01

    It is shown that the inclusion of junctions characterized by non-sinusoidal current - phase relationship in the systems composed of multiple Josephson junctions - results in the appearance of additional system phase states. Numerical simulations and stability considerations confirm that those phase states can be realized in practice. Moreover, spontaneous formation of the grain boundary junctions in high-T c superconductors with non-trivial current-phase relations due to the d-wave symmetry of the order parameter is probable. Switching between the phase states of multiple grain boundary junction systems can lead to additional 1/f noise in high-T c superconductors. (author)

  13. Monocular and binocular steady-state flicker VEPs: frequency-response functions to sinusoidal and square-wave luminance modulation.

    Science.gov (United States)

    Nicol, David S; Hamilton, Ruth; Shahani, Uma; McCulloch, Daphne L

    2011-02-01

    Steady-state VEPs to full-field flicker (FFF) using sinusoidally modulated light were compared with those elicited by square-wave modulated light across a wide range of stimulus frequencies with monocular and binocular FFF stimulation. Binocular and monocular VEPs were elicited in 12 adult volunteers to FFF with two modes of temporal modulation: sinusoidal or square-wave (abrupt onset and offset, 50% duty cycle) at ten temporal frequencies ranging from 2.83 to 58.8 Hz. All stimuli had a mean luminance of 100 cd/m(2) with an 80% modulation depth (20-180 cd/m(2)). Response magnitudes at the stimulus frequency (F1) and at the double and triple harmonics (F2 and F3) were compared. For both sinusoidal and square-wave flicker, the FFF-VEP magnitudes at F1 were maximal for 7.52 Hz flicker. F2 was maximal for 5.29 Hz flicker, and F3 magnitudes are largest for flicker stimulation from 3.75 to 7.52 Hz. Square-wave flicker produced significantly larger F1 and F2 magnitudes for slow flicker rates (up to 5.29 Hz for F1; at 2.83 and 3.75 Hz for F2). The F3 magnitudes were larger overall for square-wave flicker. Binocular FFF-VEP magnitudes are larger than those of monocular FFF-VEPs, and the amount of this binocular enhancement is not dependant on the mode of flicker stimulation (mean binocular: monocular ratio 1.41, 95% CI: 1.2-1.6). Binocular enhancement of F1 for 21.3 Hz flicker was increased to a factor of 2.5 (95% CI: 1.8-3.5). In the healthy adult visual system, FFF-VEP magnitudes can be characterized by the frequency-response functions of F1, F2 and F3. Low-frequency roll-off in the FFF-VEP magnitudes is greater for sinusoidal flicker than for square-wave flicker for rates ≤ 5.29 Hz; magnitudes for higher-frequency flicker are similar for the two types of flicker. Binocular FFF-VEPs are larger overall than those recorded monocularly, and this binocular summation is enhanced at 21.3 Hz in the mid-frequency range.

  14. Tip loss correction for actuator / Navier Stokes computations

    DEFF Research Database (Denmark)

    Shen, Wen Zhong; Sørensen, Jens Nørkær; Mikkelsen, Robert Flemming

    2004-01-01

    The new tip loss correction, initially developed for ID BEM computations [1], is now extended to 2D Actuator Disc / Navier-Stokes (AD/NS) computations and 3D Actuator Line / Navier-Stokes (AL/NS) computations. As shown in the paper, the tip loss correction is an important and necessary step...... for actuator / Navier-Stokes models. Comparisons of the present results with those obtained from a EM code with new tip correction and experimental data show that the tip loss correction is correctly implemented in the actuator / Navier-Stokes models. The results demonstrate also that difference between......, Actuator Line, Navier-Stokes equations, Tip loss correction....

  15. Selection of case studies describing PICC tip malposition.

    Science.gov (United States)

    Jackson, Andrew; Buttle, Andrew

    2016-07-28

    This article presents a number of case studies, spanning a 12-month period, associated with peripherally inserted central catheter (PICC) tip location. The aim is to generate debate around the journey PICC tips may take; it is not the purpose of this article to debate technological solutions to the issue of PICC tip location. The discussion of each case illustrates a wide range of potential aberrant PICC tip locations and offers an insight into how the abberant tip location was resolved in each case.

  16. Numerical investigation of magnetic field effect on mixed convection heat transfer of nanofluid in a channel with sinusoidal walls

    International Nuclear Information System (INIS)

    Rashidi, M.M.; Nasiri, Mohammad; Khezerloo, Marzieh; Laraqi, Najib

    2016-01-01

    In this study, mixed convection heat transfer of nano-fluid flow in vertical channel with sinusoidal walls under magnetic field effect is investigated numerically. The heat transfer and hydrodynamic characteristics have been examined. This study has performed for 500≤Re≤1000, 5×104≤Gr≤1×106 , three amplitude sine wave (0.1, 0.2 and 0.3) and three values of Hartman numbers (0, 5 and 10). Water was utilized as the base fluid and Al2O3 is the considered nano-particle. Flow is assumed two dimensional, laminar, steady and incompressible. As well the thermo-physical properties of nano-fluid are considered constant. The Boussinesq approximation used for calculated the density variations. The average Nusslet number increases by increasing the Grashof number for nano-fluids with different volume fraction. The average Nusselt and Poiseuille number increase as Reynolds number increases. Also, the average Nusselt number and Poiseuille number increases by increasing the Hartman number. - Highlights: • Mixed convection of nanofluid flow in a sinusoidal vertical channel is studied. • MHD effects on heat transfer and hydrodynamic characteristics are investigated. • The Nusselt number increases by adding the nanoparticles to the base fluid. • With applying a magnetic field, the velocity profile will be more uniform. • The Nusselt number increases by increasing the Hartman number.

  17. Numerical investigation of magnetic field effect on mixed convection heat transfer of nanofluid in a channel with sinusoidal walls

    Energy Technology Data Exchange (ETDEWEB)

    Rashidi, M.M., E-mail: mm_rashidi@sawtc.com [Shanghai Key Lab of Vehicle Aerodynamics and Vehicle Thermal Management Systems, Shanghai (China); ENN-Tongji Clean Energy Institute of Advanced Studies, Shanghai (China); Nasiri, Mohammad, E-mail: m.nasiri1989@gmail.com [Faculty of Mechanical Engineering, University of Tabriz, Tabriz (Iran, Islamic Republic of); Khezerloo, Marzieh, E-mail: m.khezerloo91@ms.tabrizu.ac.ir [Faculty of Mechanical Engineering, University of Tabriz, Tabriz (Iran, Islamic Republic of); Laraqi, Najib, E-mail: najib.laraqi@u-paris10.fr [Universite Paris 10, LTIE, EA 4415, GTE, 50 Rue de Sevres, F92410 Ville d' Avray (France)

    2016-03-01

    In this study, mixed convection heat transfer of nano-fluid flow in vertical channel with sinusoidal walls under magnetic field effect is investigated numerically. The heat transfer and hydrodynamic characteristics have been examined. This study has performed for 500≤Re≤1000, 5×104≤Gr≤1×106 , three amplitude sine wave (0.1, 0.2 and 0.3) and three values of Hartman numbers (0, 5 and 10). Water was utilized as the base fluid and Al2O3 is the considered nano-particle. Flow is assumed two dimensional, laminar, steady and incompressible. As well the thermo-physical properties of nano-fluid are considered constant. The Boussinesq approximation used for calculated the density variations. The average Nusslet number increases by increasing the Grashof number for nano-fluids with different volume fraction. The average Nusselt and Poiseuille number increase as Reynolds number increases. Also, the average Nusselt number and Poiseuille number increases by increasing the Hartman number. - Highlights: • Mixed convection of nanofluid flow in a sinusoidal vertical channel is studied. • MHD effects on heat transfer and hydrodynamic characteristics are investigated. • The Nusselt number increases by adding the nanoparticles to the base fluid. • With applying a magnetic field, the velocity profile will be more uniform. • The Nusselt number increases by increasing the Hartman number.

  18. Effect of a selective rise in sinusoidal norepinephrine on HGP is due to an increase in glycogenolysis.

    Science.gov (United States)

    Chu, C A; Sindelar, D K; Neal, D W; Allen, E J; Donahue, E P; Cherrington, A D

    1998-01-01

    To determine the effect of a selective rise in liver sinusoidal norepinephrine (NE) on hepatic glucose production (HGP), norepinephrine (50 ng.kg-1.min-1) was infused intraportally (Po-NE) for 3 h into five 18-h-fasted conscious dogs with a pancreatic clamp. In the control protocol, NE (0.2 ng.kg-1.min-1) and glucose were infused peripherally to match the arterial NE and blood glucose levels in the Po-NE group. Hepatic sinusoidal NE levels rose approximately 30-fold in the Po-NE group but did not change in the control group. The arterial NE levels did not change significantly in either group. During the portal NE infusion, HGP increased from 1.9 +/- 0.2 to 3.5 +/- 0.4 mg.kg-1.min-1 (15 min; P glycogenolysis. Compared with the previously determined effects of epinephrine or glucagon on HGP, the effect of NE is, on a molar basis, less potent but more sustained over time.

  19. Sinusoidal obstruction syndrome (veno-occlusive disease in a patient receiving bevacizumab for metastatic colorectal cancer: a case report

    Directory of Open Access Journals (Sweden)

    Agarwal Vijay

    2008-07-01

    Full Text Available Abstract Introduction We present the case of a patient with colon cancer who, while receiving bevacizumab, developed sinusoidal obstruction syndrome (veno-occlusive disease (SOSVOD. Certain antitumour agents such as 6-mercaptopurine and 6-thioguanine have also been reported to initiate hepatic SOSVOD in isolated cases. There have been no reports so far correlating bevacizumab with SOSVOD. Case presentation A 77-year-old man was being treated with oxaliplatin and a modified de Gramont regimen of 5-fluorouracil for metastatic colon cancer. Bevacizumab (7.5 mg/kg was added from the seventh cycle onwards. Protracted neutropenia and thrombocytopenia led to discontinuation of oxaliplatin after the ninth cycle. A computed tomography scan showed complete response and bevacizumab was continued for another 3 months, after which time the patient developed right hypochondrial pain, transudative ascites, splenomegaly and abnormal liver function tests. Upper gastrointestinal endoscopy showed oesophageal varices. Liver biopsy showed features considered to be consistent with SOSVOD. Bevacizumab was stopped and a policy of watchful waiting was adopted. He tolerated the acute damage to his liver and subsequently the ascites resolved and liver function tests normalised. Conclusion We need to be aware that bevacizumab can cause sinusoidal obstruction syndrome (veno-occlusive disease and that the occurrence of ascites should not be attributed to progressive disease without appropriate evaluation.

  20. Time-frequency analyses of fluid–solid interaction under sinusoidal translational shear deformation of the viscoelastic rat cerebrum

    Science.gov (United States)

    Leahy, Lauren N.; Haslach, Henry W.

    2018-02-01

    During normal extracellular fluid (ECF) flow in the brain glymphatic system or during pathological flow induced by trauma resulting from impacts and blast waves, ECF-solid matter interactions result from sinusoidal shear waves in the brain and cranial arterial tissue, both heterogeneous biological tissues with high fluid content. The flow in the glymphatic system is known to be forced by pulsations of the cranial arteries at about 1 Hz. The experimental shear stress response to sinusoidal translational shear deformation at 1 Hz and 25% strain amplitude and either 0% or 33% compression is compared for rat cerebrum and bovine aortic tissue. Time-frequency analyses aim to correlate the shear stress signal frequency components over time with the behavior of brain tissue constituents to identify the physical source of the shear nonlinear viscoelastic response. Discrete fast Fourier transformation analysis and the novel application to the shear stress signal of harmonic wavelet decomposition both show significant 1 Hz and 3 Hz components. The 3 Hz component in brain tissue, whose magnitude is much larger than in aortic tissue, may result from interstitial fluid induced drag forces. The harmonic wavelet decomposition locates 3 Hz harmonics whose magnitudes decrease on subsequent cycles perhaps because of bond breaking that results in easier fluid movement. Both tissues exhibit transient shear stress softening similar to the Mullins effect in rubber. The form of a new mathematical model for the drag force produced by ECF-solid matter interactions captures the third harmonic seen experimentally.

  1. Contrast-enhanced ultrasonography of hepatocellular carcinoma: Correlation between quantitative parameters and arteries in neoangiogenesis or sinusoidal capillarization

    International Nuclear Information System (INIS)

    Pei Xiaoqing; Liu Longzhong; Zheng Wei; Cai Muyan; Han Feng; He Jiehua; Li Anhua; Chen Minshan

    2012-01-01

    Objective: The quantitative parameters in contrast-enhanced ultrasonography-time–intensity curve of hepatocellular carcinoma (HCC) were studied to explore their potential importance in monitoring the effects of anti-angiogenic therapy for HCC. Methods: 115 HCC patients were studied with contrast-enhanced ultrasonography-time–intensity curve (CEUS-TIC) and with immunohistochemical analysis of tissue sections. The CEUS images were analyzed off-line to obtained quantitative parameters including maximum of intensity (IMAX), rise time (RT), time to peak (TTP), mean transit time (mTT), rise slope (RS), and washout time (WT). Monoclonal antibodies specific for smooth muscle actin and anti-CD34 were used to observe unpaired arteries (UAs) and microvessel area (MVA) of sinusoidal capillarization, respectively. The UAs and MVA of 82 HCC cases were successfully stained. Results: The number of UAs had moderate correlation with RT (r = −0.446), TTP (r = −0.432), and RS (r = 0.431) (P < 0.05), and it had mild correlation with IMAX (r = 0.303) and WT (r = 0.285) (P < 0.05). MVA of sinusoidal capillarization had no correlation with perfusion parameters. Conclusion: Quantitative CEUS-TIC parameters reflecting hemodynamics of tumors are correlated with UAs, but not with MVA, and they might be used to monitor the effects of anti-angiogenic therapy on HCC.

  2. Relocalization of human chromatin remodeling cofactor TIP48 in mitosis

    International Nuclear Information System (INIS)

    Sigala, Barbara; Edwards, Mina; Puri, Teena; Tsaneva, Irina R.

    2005-01-01

    TIP48 is a highly conserved eukaryotic AAA + protein which is an essential cofactor for several complexes involved in chromatin acetylation and remodeling, transcriptional and developmental regulation and nucleolar organization and trafficking. We show that TIP48 abundance in HeLa cells did not change during the cell cycle, nor did its distribution in various biochemical fractions. However, we observed distinct changes in the subcellular localization of TIP48 during M phase using immunofluorescence microscopy. Our studies demonstrate that in interphase cells TIP48 was found mainly in the nucleus and exhibited a distinct localization in the nuclear periphery. As the cells entered mitosis, TIP48 was excluded from the condensing chromosomes but showed association with the mitotic apparatus. During anaphase, some TIP48 was detected in the centrosome colocalizing with tubulin but the strongest staining appeared in the mitotic equator associated with the midzone central spindle. Accumulation of TIP48 in the midzone and the midbody was observed in late telophase and cytokinesis. This redeployment of TIP48 during anaphase and cytokinesis was independent of microtubule assembly. The relocation of endogenous TIP48 to the midzone/midbody under physiological conditions suggests a novel and distinct function for TIP48 in mitosis and possible involvement in the exit of mitosis

  3. Numerical Simulation of LVAD Inflow Cannulas with Different Tip

    Directory of Open Access Journals (Sweden)

    Guang-Mao Liu

    2012-01-01

    Full Text Available The tip structure of LVAD inflow cannula is one of major factors to lead adverse events such as thrombosis and suction leading to obstruction. In this research, four kinds of tips that had been used in inflow cannulas were selected and designed. The flow field of the four inflow cannulas inserted into the apex of left ventricle (LV was numerically computed by computational fluid dynamics. The flow behavior was analyzed in order to compare the blood compatibility and suction in left ventricle and cannulas after the inflow cannulas with different tips were inserted to the apex of LV. The results showed that the cannula tip structure affected the LVAD performance. Among these four cannulas, the trumpet-tipped inflow cannula owned the best performance in smooth flow velocity distribution without backflow or low-velocity flow so that it was the best in blood compatibility. Nevertheless, the caged tipped cannula was the worst in blood compatibility. And the blunt-tipped and beveled tipped inflow cannulas may obstruct more easily than trumpet and caged tipped inflow cannulas because of their shape. The study indicated that the trumpet tip was the most preferable for the inflow cannula of long-term LVAD.

  4. [Plastic micro-tips for drug delivery].

    Science.gov (United States)

    Muslija, A; Guber, A E; Heckele, M; Herrmann, D; Pfleging, W; Schaller, Th

    2002-01-01

    Removal or exact transfer of minimum substance volumes from reservoirs or microfluidic systems may be accomplished by means of miniaturized tips with integrated through-going capillaries. Applications in biomedical engineering, e.g. for the application of drugs, or in life sciences, e.g. equipping of microarrays, require the use of disposable plastic products for hygienic reasons and reasons of costs. For this purpose, a method to fabricate microtips out of plastic by doublesided molding has been developed at the Forschungszentrum Karlsruhe.

  5. Semi-empirical crack tip analysis

    Science.gov (United States)

    Chudnovsky, A.; Ben Ouezdon, M.

    1988-01-01

    Experimentally observed crack opening displacements are employed as the solution of the multiple crack interaction problem. Then the near and far fields are reconstructed analytically by means of the double layer potential technqiue. Evaluation of the effective stress intensity factor resulting from the interaction of the main crack and its surrounding crazes in addition to the remotely applied load is presented as an illustrative example. It is shown that crazing (as well as microcracking) may constitute an alternative mechanism to Dugdale-Berenblatt models responsible for the cancellation of the singularity at the crack tip.

  6. Efficient Transdermal Delivery of Alendronate, a Nitrogen-Containing Bisphosphonate, Using Tip-Loaded Self-Dissolving Microneedle Arrays for the Treatment of Osteoporosis.

    Science.gov (United States)

    Katsumi, Hidemasa; Tanaka, Yutaro; Hitomi, Kaori; Liu, Shu; Quan, Ying-Shu; Kamiyama, Fumio; Sakane, Toshiyasu; Yamamoto, Akira

    2017-08-17

    To improve the transdermal bioavailability and safety of alendronate (ALN), a nitrogen-containing bisphosphonate, we developed self-dissolving microneedle arrays (MNs), in which ALN is loaded only at the tip portion of micron-scale needles by a dip-coating method (ALN(TIP)-MN). We observed micron-scale pores in rat skin just after application of ALN(TIP)-MN, indicating that transdermal pathways for ALN were created by MN. ALN was rapidly released from the tip of MNs as observed in an in vitro release study. The tip portions of MNs completely dissolved in the rat skin within 5 min after application in vivo. After application of ALN(TIP)-MN in mice, the plasma concentration of ALN rapidly increased, and the bioavailability of ALN was approximately 96%. In addition, the decrease in growth plate was effectively suppressed by this efficient delivery of ALN in a rat model of osteoporosis. Furthermore, no skin irritation was observed after application of ALN(TIP)-MN and subcutaneous injection of ALN, while mild skin irritation was induced by whole-ALN-loaded MN (ALN-MN)-in which ALN is contained in the whole of the micron-scale needles fabricated from hyaluronic acid-and intradermal injection of ALN. These findings indicate that ALN(TIP)-MN is a promising transdermal formulation for the treatment of osteoporosis without skin irritation.

  7. Driving and control strategies in alternative current machines of permanent magnet with non-sinusoidal flux; Estrategias de acionamento e controle em maquinas CA de ima permanente com fluxo nao senoidal

    Energy Technology Data Exchange (ETDEWEB)

    Monteiro, Jose Roberto Boffino de Almeida

    1997-07-01

    The aim of this work is to study and analyze the torque performance of brush less machines with non-sinusoidal distributed magnetic fluxes. The machine type considered is a surface mount permanent magnet brush less machine. Three mathematical models for the machine are considered: the per stator phase, the vectorial and the linear second order speed-voltage models. Machines with different stator windings are compared including the permanent magnet synchronous machines with sinusoidal distributed stator windings. The torque outputs of these machines are obtained considering two kinds of open loop driving systems: one with a six-pulse waveform and other with a sinusoidal waveform. Finally, a vectorial control is proposed for the non-sinusoidal machines. The torque ripple as well the overall performance of non-sinusoidal machines with vectorial control is compared to that of sinusoidal machines. (author)

  8. High Throughput Nanofabrication of Silicon Nanowire and Carbon Nanotube Tips on AFM Probes by Stencil-Deposited Catalysts

    DEFF Research Database (Denmark)

    Engstrøm, Daniel Southcott; Savu, Veronica; Zhu, Xueni

    2011-01-01

    A new and versatile technique for the wafer scale nanofabrication of silicon nanowire (SiNW) and multiwalled carbon nanotube (MWNT) tips on atomic force microscope (AFM) probes is presented. Catalyst material for the SiNW and MWNT growth was deposited on prefabricated AFM probes using aligned wafer...

  9. Kinetics-Driven Crystal Facets Evolution at the Tip of Nanowires: A New Implementation of the Ostwald-Lussac Law.

    Science.gov (United States)

    Yin, Xin; Wang, Xudong

    2016-11-09

    Nanocrystal facets evolution is critical for designing nanomaterial morphology and controlling their properties. In this work, we report a unique high-energy crystal facets evolution phenomenon at the tips of wurtzite zinc oxide nanowires (NWs). As the zinc vapor supersaturation decreased at the NW deposition region, the NW tip facets evolved from the (0001) surface to the {101̅3} surface and subsequently to the {112̅2} surface and eventually back to the flat (0001) surface. A series of NW tip morphology was observed in accordance to the different combinations of exposed facets. Exposure of the high-energy facets was attributed to the fluctuation of the energy barriers for the formation of different crystal facets during the layer-by-layer growth of the NW tip. The energy barrier differences between these crystal facets were quantified from the surface area ratios as a function of supersaturation. On the basis of the experimental observation and kinetics analysis, we argue that at appropriate deposition conditions exposure of the crystal facets at NW growth front is not merely determined by the surface energy. Instead, the NW may choose to expose the facets with minimal formation energy barrier, which can be determined by the Ehrlich-Schwoebel barrier variation. This empirical law for the NW tip facet formation was in analogy to the Ostwald-Lussac law of phase transformation, which brings a new insight toward nanostructure design and controlled synthesis.

  10. Turbine-blade tip clearance and tip timing measurements using an optical fiber bundle sensor

    Science.gov (United States)

    Garcia, Iker; Beloki, Josu; Zubia, Joseba; Durana, Gaizka; Aldabaldetreku, Gotzon

    2013-04-01

    Traditional limitations of capacitive, inductive or discharging probe sensor for tip timing and tip clearance measurements are overcome by reflective intensity modulated optical fiber sensors. This paper presents the signals and results corresponding to a one stage turbine rig which rotor has 146 blades, obtained from a transonic wind-tunnel test. The probe is based on a trifurcated bundle of optical fibers that is mounted on turbine casing. It is composed of a central illuminating fiber that guides the light from a laser to the turbine blade, and two concentric rings of receiving fibers that collect the reflected light. Two photodetectors turn this reflected light signal from the receiving rings into voltage. The electrical signals are acquired and saved by a high-sample-rate oscilloscope. In tip clearance calculations the ratio of the signals provided by each ring of receiving fibers is evaluated and translated into distance. In the case of tip timing measurements, only one of the signals is considered to get the arrival time of the blade. The differences between the real and theoretical arrival times of the blades are used to obtain the deflections amplitude. The system provides the travelling wave spectrum, which presents the average vibration amplitude of the blades at a certain nodal diameter. The reliability of the results in the turbine rig testing facilities suggests the possibility of performing these measurements in real turbines under real working conditions.

  11. Quantification of tip-broadening in non-contact atomic force microscopy with carbon nanotube tips

    DEFF Research Database (Denmark)

    Meinander, Kristoffer; Jensen, Thomas N.; Simonsen, Soren B.

    2012-01-01

    Carbon nanotube terminated atomic force microscopy (AFM) probes have been used for the imaging of 5 nm wide surface supported Pt nanoclusters by non-contact (dynamic mode) AFM in an ultra-high vacuum. The results are compared to AFM measurements done with conventional Si-tips, as well...

  12. Tipping point analysis of ocean acoustic noise

    Science.gov (United States)

    Livina, Valerie N.; Brouwer, Albert; Harris, Peter; Wang, Lian; Sotirakopoulos, Kostas; Robinson, Stephen

    2018-02-01

    We apply tipping point analysis to a large record of ocean acoustic data to identify the main components of the acoustic dynamical system and study possible bifurcations and transitions of the system. The analysis is based on a statistical physics framework with stochastic modelling, where we represent the observed data as a composition of deterministic and stochastic components estimated from the data using time-series techniques. We analyse long-term and seasonal trends, system states and acoustic fluctuations to reconstruct a one-dimensional stochastic equation to approximate the acoustic dynamical system. We apply potential analysis to acoustic fluctuations and detect several changes in the system states in the past 14 years. These are most likely caused by climatic phenomena. We analyse trends in sound pressure level within different frequency bands and hypothesize a possible anthropogenic impact on the acoustic environment. The tipping point analysis framework provides insight into the structure of the acoustic data and helps identify its dynamic phenomena, correctly reproducing the probability distribution and scaling properties (power-law correlations) of the time series.

  13. Ten tips for authors of scientific articles.

    Science.gov (United States)

    Hong, Sung-Tae

    2014-08-01

    Writing a good quality scientific article takes experience and skill. I propose 'Ten Tips' that may help to improve the quality of manuscripts for scholarly journals. It is advisable to draft first version of manuscript and revise it repeatedly for consistency and accuracy of the writing. During the drafting and revising the following tips can be considered: 1) focus on design to have proper content, conclusion, points compliant with scope of the target journal, appropriate authors and contributors list, and relevant references from widely visible sources; 2) format the manuscript in accordance with instructions to authors of the target journal; 3) ensure consistency and logical flow of ideas and scientific facts; 4) provide scientific confidence; 5) make your story interesting for your readers; 6) write up short, simple and attractive sentences; 7) bear in mind that properly composed and reflective titles increase chances of attracting more readers; 8) do not forget that well-structured and readable abstracts improve citability of your publications; 9) when revising adhere to the rule of 'First and Last' - open your text with topic paragraph and close it with resolution paragraph; 10) use connecting words linking sentences within a paragraph by repeating relevant keywords.

  14. Aperiodicity Correction for Rotor Tip Vortex Measurements

    Science.gov (United States)

    Ramasamy, Manikandan; Paetzel, Ryan; Bhagwat, Mahendra J.

    2011-01-01

    The initial roll-up of a tip vortex trailing from a model-scale, hovering rotor was measured using particle image velocimetry. The unique feature of the measurements was that a microscope was attached to the camera to allow much higher spatial resolution than hitherto possible. This also posed some unique challenges. In particular, the existing methodologies to correct for aperiodicity in the tip vortex locations could not be easily extended to the present measurements. The difficulty stemmed from the inability to accurately determine the vortex center, which is a prerequisite for the correction procedure. A new method is proposed for determining the vortex center, as well as the vortex core properties, using a least-squares fit approach. This approach has the obvious advantage that the properties are derived from not just a few points near the vortex core, but from a much larger area of flow measurements. Results clearly demonstrate the advantage in the form of reduced variation in the estimated core properties, and also the self-consistent results obtained using three different aperiodicity correction methods.

  15. Tipping point analysis of ocean acoustic noise

    Directory of Open Access Journals (Sweden)

    V. N. Livina

    2018-02-01

    Full Text Available We apply tipping point analysis to a large record of ocean acoustic data to identify the main components of the acoustic dynamical system and study possible bifurcations and transitions of the system. The analysis is based on a statistical physics framework with stochastic modelling, where we represent the observed data as a composition of deterministic and stochastic components estimated from the data using time-series techniques. We analyse long-term and seasonal trends, system states and acoustic fluctuations to reconstruct a one-dimensional stochastic equation to approximate the acoustic dynamical system. We apply potential analysis to acoustic fluctuations and detect several changes in the system states in the past 14 years. These are most likely caused by climatic phenomena. We analyse trends in sound pressure level within different frequency bands and hypothesize a possible anthropogenic impact on the acoustic environment. The tipping point analysis framework provides insight into the structure of the acoustic data and helps identify its dynamic phenomena, correctly reproducing the probability distribution and scaling properties (power-law correlations of the time series.

  16. Effects of plastic anisotropy on crack-tip behaviour

    DEFF Research Database (Denmark)

    Legarth, Brian Nyvang; Tvergaard, Viggo; Kuroda, Mitsutoshi

    2002-01-01

    For a crack in a homogeneous material the effect of plastic anisotropy on crack-tip blunting and on the near-tip stress and strain fields is analyzed numerically. The full finite strain analyses are carried out for plane strain under small scale yielding conditions, with purely symmetric mode I...... loading remote from the crack-tip. In cases where the principal axes of the anisotropy are inclined to the plane of the crack it is found that the plastic zones as well as the stress and strain fields just around the blunted tip of the crack become non-symmetric. In these cases the peak strain...... on the blunted tip occurs off the center line of the crack, thus indicating that the crack may want to grow in a different direction. When the anisotropic axes are parallel to the crack symmetry is retained, but the plastic zones and the near-tip fields still differ from those predicted by standard isotropic...

  17. Dynamic of cold-atom tips in anharmonic potentials

    Science.gov (United States)

    Menold, Tobias; Federsel, Peter; Rogulj, Carola; Hölscher, Hendrik; Fortágh, József

    2016-01-01

    Background: Understanding the dynamics of ultracold quantum gases in an anharmonic potential is essential for applications in the new field of cold-atom scanning probe microscopy. Therein, cold atomic ensembles are used as sensitive probe tips to investigate nanostructured surfaces and surface-near potentials, which typically cause anharmonic tip motion. Results: Besides a theoretical description of this anharmonic tip motion, we introduce a novel method for detecting the cold-atom tip dynamics in situ and real time. In agreement with theory, the first measurements show that particle interactions and anharmonic motion have a significant impact on the tip dynamics. Conclusion: Our findings will be crucial for the realization of high-sensitivity force spectroscopy with cold-atom tips and could possibly allow for the development of advanced spectroscopic techniques such as Q-control. PMID:28144505

  18. Embolization with the Amplatzer Vascular Plug in TIPS Patients

    International Nuclear Information System (INIS)

    Pattynama, Peter M. T.; Wils, Alexandra; Linden, Edwin van der; Dijk, Lukas C. van

    2007-01-01

    Vessel embolization can be a valuable adjunct procedure in transjugular intrahepatic portosystemic shunt (TIPS). During the creation of a TIPS, embolization of portal vein collaterals supplying esophageal varices may lower the risk of secondary rebleeding. And after creation of a TIPS, closure of the TIPS itself may be indicated if the resulting hepatic encephalopathy severely impairs mental functioning. The Amplatzer Vascular Plug (AVP; AGA Medical, Golden Valley, MN) is well suited for embolization of large-diameter vessels and has been employed in a variety of vascular lesions including congenital arteriovenous shunts. Here we describe the use of the AVP in the context of TIPS to embolize portal vein collaterals (n = 8) or to occlude the TIPS (n = 2)

  19. Temperature-controlled irrigated tip radiofrequency catheter ablation

    DEFF Research Database (Denmark)

    Petersen, H H; Chen, X; Pietersen, Adrian

    1998-01-01

    INTRODUCTION: In patients with ventricular tachycardias due to structural heart disease, catheter ablation cures radiofrequency ablation. Irrigated tip radiofrequency ablation using power control and high infusion rates enlarges lesion......: We conclude that temperature-controlled radiofrequency ablation with irrigated tip catheters using low target temperature and low infusion rate enlarges lesion size without increasing the incidence of cratering and reduces coagulum formation of the tip....

  20. DO SLOVENIAN DEALERS USE TECHNIQUES FOR INCREASING THEIR TIPS?

    Directory of Open Access Journals (Sweden)

    Andrej Raspor

    2016-05-01

    Full Text Available In 1996 Michael Lynn introduced the idea that restaurant managers could increase tips for their waiters and thus increase turnover by training the waiters to engage tip-enhancing behaviours. Since then, the list of tip-enhancing behaviours has expanded. Therefore the potential to increase tips is more accessible. The purpose of this paper was to examine how Slovenian dealers use strategies to increase their tips. We tested fourteen techniques to increase tips. The study was carried out among 473 gaming employees, 279 of which are dealers, in the Slovenian gaming industry, in order to find out how they use these techniques and which of them can bring about an increase in their tips. The study showed that Slovenian dealers mostly do not use these techniques, and that the dealers who do use them tend to receive tips more often. The findings imply that managers and employees should be informed of these techniques in order to increase tips and their overall income. Practical implications are that we suggest that management considers these ideas for increasing flexibility and reducing the cost of work: (1 informing dealers on ways of increasing tips, (2 including the acquisition of this specific knowledge in their career plans, (3 carrying out a reform of the reward system which would include tips. Social implications will be shown in a higher gaming revenue. It is very likely – as shown in our research – that employees will receive higher wages as these will be topped up by tips. The state, in turn, will collect more taxes.

  1. Energy Savers Tips on Saving Energy& Money at Home

    Energy Technology Data Exchange (ETDEWEB)

    2003-06-01

    Provides consumers with home energy and money savings tips such as insulation, weatherization, heating, cooling, water heating, energy efficient windows, landscaping, lighting, and energy efficient appliances

  2. Is a Drain Tip Culture Required After Spinal Surgery?

    Science.gov (United States)

    Kobayashi, Kazuyoshi; Imagama, Shiro; Ito, Zenya; Ando, Kei; Yagi, Hideki; Hida, Tetsuro; Ito, Kenyu; Ishikawa, Yoshimoto; Tsushima, Mikito; Ishiguro, Naoki

    2017-10-01

    The efficacy of use of a drain tip culture for early detection of surgical-site infection (SSI) was investigated in 329 patients after spinal surgery. To examine the efficacy of a wound drain tip culture for detection of SSI in spinal surgery. A complication of SSI after spinal surgery has high associated morbidity and mortality, and is often difficult to treat. The subjects were patients who underwent spinal surgery at our institution between January 2010 and March 2013. All subjects were treated with antimicrobial prophylaxis based on evidence-based guidelines and were followed for at least 6 months after surgery. Data from culture studies using the distal tip of the wound drain were used for analysis. Drain tip cultures were positive in 34 cases and there were 19 SSIs. Ten of the 34-tip culture-positive wounds developed SSI. Drain tip cultures had a sensitivity of 52%, specificity of 92%, positive predictive value (PPV) of 29%, and negative predictive value of 97% for predicting a wound infection. The association between a positive suction tip culture and wound infection was significant (P<0.05). The PPV for SSI was 60% in cases in which methicillin-resistant bacteria were detected in a drain tip, and the SSI rate in these cases differed significantly compared with those with non-methicillin-resistant bacteria (P=0.01). A drain tip culture is useful for early detection of SSI caused by methicillin-resistant bacteria.

  3. Microneedles array with biodegradable tips for transdermal drug delivery

    Science.gov (United States)

    Iliescu, Ciprian; Chen, Bangtao; Wei, Jiashen; Tay, Francis E. H.

    2008-12-01

    The paper presented an enhancement solution for transdermal drug delivery using microneedles array with biodegradable tips. The microneedles array was fabricated by using deep reactive ion etching (DRIE) and the biodegradable tips were made to be porous by electrochemical etching process. The porous silicon microneedle tips can greatly enhance the transdermal drug delivery in a minimum invasion, painless, and convenient manner, at the same time; they are breakable and biodegradable. Basically, the main problem of the silicon microneedles consists of broken microneedles tips during the insertion. The solution proposed is to fabricate the microneedle tip from a biodegradable material - porous silicon. The silicon microneedles are fabricated using DRIE notching effect of reflected charges on mask. The process overcomes the difficulty in the undercut control of the tips during the classical isotropic silicon etching process. When the silicon tips were formed, the porous tips were then generated using a classical electrochemical anodization process in MeCN/HF/H2O solution. The paper presents the experimental results of in vitro release of calcein and BSA with animal skins using a microneedle array with biodegradable tips. Compared to the transdermal drug delivery without any enhancer, the microneedle array had presented significant enhancement of drug release.

  4. Terahertz Nanofocusing with Cantilevered Terahertz-Resonant Antenna Tips.

    Science.gov (United States)

    Mastel, Stefan; Lundeberg, Mark B; Alonso-González, Pablo; Gao, Yuanda; Watanabe, Kenji; Taniguchi, Takashi; Hone, James; Koppens, Frank H L; Nikitin, Alexey Y; Hillenbrand, Rainer

    2017-11-08

    We developed THz-resonant scanning probe tips, yielding strongly enhanced and nanoscale confined THz near fields at their tip apex. The tips with length in the order of the THz wavelength (λ = 96.5 μm) were fabricated by focused ion beam (FIB) machining and attached to standard atomic force microscopy (AFM) cantilevers. Measurements of the near-field intensity at the very tip apex (25 nm radius) as a function of tip length, via graphene-based (thermoelectric) near-field detection, indicate their first and second order geometrical antenna resonances for tip length of 33 and 78 μm, respectively. On resonance, we find that the near-field intensity is enhanced by one order of magnitude compared to tips of 17 μm length (standard AFM tip length), which is corroborated by numerical simulations that further predict remarkable intensity enhancements of about 10 7 relative to the incident field. Because of the strong field enhancement and standard AFM operation of our tips, we envision manifold and straightforward future application in scattering-type THz near-field nanoscopy and THz photocurrent nanoimaging, nanoscale nonlinear THz imaging, or nanoscale control and manipulation of matter employing ultrastrong and ultrashort THz pulses.

  5. Energy Savers: Tips on Saving Money & Energy at Home

    Energy Technology Data Exchange (ETDEWEB)

    None

    2011-12-01

    Provides consumers with home energy and money savings tips such as insulation, weatherization, heating, cooling, water heating, energy efficient windows, landscaping, lighting, and energy efficient appliances.

  6. Dependence of electric field on STM tip preparation

    DEFF Research Database (Denmark)

    Huang, D.H.; Grey, Francois; Aono, M.

    1998-01-01

    Voltage pulses applied between an STM tip and a surface can modify the surface on the nanometer scale due to electric-field-induced evaporation. However, at present, different groups have achieved surface modification with quite different bias conditions, and it is still difficult to obtain high...... reproducibility in such experiments. In this paper, we measure the tip displacement during a pulse at constant tunnelling current, and deduce that the electric field produced by the pulse depends in a systematic way on tip preparation, The results show how differences in tip preparation can be a major source...

  7. Energy Saver: Tips on Saving Money & Energy at Home

    Energy Technology Data Exchange (ETDEWEB)

    None

    2017-09-01

    Provides consumers with home energy and money savings tips such as insulation, weatherization, heating, cooling, water heating, energy efficient windows, landscaping, lighting, and energy efficient appliances.

  8. Wettability of AFM tip influences the profile of interfacial nanobubbles

    Science.gov (United States)

    Teshima, Hideaki; Takahashi, Koji; Takata, Yasuyuki; Nishiyama, Takashi

    2018-02-01

    To accurately characterize the shape of interfacial nanobubbles using atomic force microscopy (AFM), we investigated the effect of wettability of the AFM tip while operating in the peak force tapping (PFT) mode. The AFM tips were made hydrophobic and hydrophilic by Teflon AF coating and oxygen plasma treatment, respectively. It was found that the measured base radius of nanobubbles differed between AFM height images and adhesion images, and that this difference depended on the tip wettability. The force curves obtained during the measurements were also different depending on the wettability, especially in the range of the tip/nanobubble interaction and in the magnitude of the maximum attractive force in the retraction period. The difference suggests that hydrophobic tips penetrate the gas/liquid interface of the nanobubbles, with the three phase contact line being pinned on the tip surface; hydrophilic tips on the other hand do not penetrate the interface. We then quantitatively estimated the pinning position and recalculated the true profiles of the nanobubbles by comparing the height images and adhesion images. As the AFM tip was made more hydrophilic, the penetration depth decreased and eventually approached zero. This result suggests that the PFT measurement using a hydrophilic tip is vital for the acquisition of reliable nanobubble profiles.

  9. On open and closed tips of bunsen burner flames

    Science.gov (United States)

    Kozlovsky, G.; Sivashinsky, G. I.

    1994-04-01

    An adiabatic, constant-density reaction-diffusion-advection model for the Bunsen burner flame tip is studied numerically. It is shown that for Lewis numbers exceeding unity the reaction rate and flame speed gradually increase toward the flame tip. For small Lewis numbers the picture is quite different. The reaction rate drops near the tip. In spite of this the flame survives and, moreover, manages to consume all the fuel supplied to the reaction zone. There is no leakage of the fuel through the front. The flame speed varies nonmonotonously along the front from gradual reduction to steep increase near the tip.

  10. Energy Savers: Tips on Saving Money & Energy at Home

    Energy Technology Data Exchange (ETDEWEB)

    None

    2014-05-01

    Provides consumers with home energy and money savings tips such as insulation, weatherization, heating, cooling, water heating, energy efficient windows, landscaping, lighting, and energy efficient appliances.

  11. Study of Heat Transfer with Nonlinear Thermal Radiation on Sinusoidal Motion of Magnetic Solid Particles in a Dusty Fluid

    Science.gov (United States)

    Bhatti, M. M.; Zeeshan, A.; Ellahi, R.

    2016-09-01

    In this article, heat transfer with nonlinear thermal radiation on sinusoidal motion of magnetic solid particles in a dust Jeffrey fluid has been studied. The effects of Magnetohydrodynamic (MHD) and hall current are also taken under consideration. The governing equation of motion and energy equation are modelled with help of Ohms law for fluid and dust phases. The solutions of the resulting ordinary coupled partial differential equations are solved analytically. The impact of all the physical parameters of interest such as Hartmann number, slip parameter, Hall parameter, radiation parameter, Prandtl number, Eckert number and particle volume fraction are demonstrated mathematically and graphically. Trapping mechanism is also discussed in detail by drawing contour lines. The present analysis affirms many interesting behaviours, which permit further study on solid particles motion with heat and mass transfer.

  12. Three dimensional dynamic study of a metal halide thallium iodine discharge plasma powered by a sinusoidal and square signal

    Science.gov (United States)

    Bechir Ben Hamida, Mohamed; Charrada, Kamel

    2016-01-01

    The purpose of this paper is to study the dynamic of a metal halide thallium iodine discharge lamp fed by a sinusoidal and square power supply. For this, a chemical model under Local Thermodynamic Equilibrium conditions has been developed to compute the plasma composition and transport coefficients such as thermal conductivity, viscosity and electric conductivity. This is then coupled with a three-dimensional time-dependent code that solves the system of the mass, energy and momentum equations, as well as the Laplace equation for the plasma using Comsol Multiphysics with Matlab. After validation with the experimental results, this model was applied to analyze the influence of the key parameters on the discharge behavior such as frequency for an AC arc current and the atomic ratio for square arc-current wave form on the convective process.

  13. "Pre-emptive strike"-the case for early treatment of hepatic sinusoidal obstruction syndrome with defibrotide.

    Science.gov (United States)

    Rajagopal, Revathi; Phillips, Marianne; Gottardo, Nicholas G

    2018-03-14

    The initial signs of hepatic sinusoidal obstruction syndrome (HSOS) can be challenging to recognize in children, especially outside the hematopoietic stem cell transplantation setting. To assist clinicians to promptly identify HSOS, the European Society for Blood and Marrow Transplantation has proposed pediatric HSOS diagnostic criteria which emphasize unexplained consumptive and transfusion-refractory thrombocytopenia. To highlight the importance of these "bellwether" early signs of HSOS and the efficacy of pre-emptive treatment with defibrotide, we describe the case of a child with a right 11th rib primitive neuroectodermal tumor who developed HSOS following focal radiotherapy and actinomycin-D treatment. © 2018 The Authors. Pediatric Blood & Cancer Published by Wiley Periodicals, Inc.

  14. Manifestations and management of veno-occlusive disease/sinusoidal obstruction syndrome in the era of contemporary therapies.

    Science.gov (United States)

    Tewari, Priti; Wallis, Whitney; Kebriaei, Partow

    2017-02-01

    The concept of veno-occlusive disease (VOD), along with our understanding of it, has historically been and remains an evolving phenomenon. This review presents a broad view of VOD, also known as sinusoidal obstruction syndrome (SOS), including (1) traditional hematopoietic stem cell transplant-associated VOD/SOS, (2) late-onset VOD/SOS, (3) pulmonary VOD, and (4) VOD/SOS associated with chemotherapy only. Several VOD/SOS management modalities exist that include modes for both prophylaxis and treatment. An extensive review of the literature on monoclonal antibodies, both approved and pending approval by the US Food and Drug Administration, reveals that only a few have been associated with an increased risk for VOD/SOS. In fact, bevacizumab appears to have a protective effect against the development of VOD/SOS. As the landscape of cancer treatment changes, careful attention needs to be focused on how new therapies affect the incidence of VOD/SOS.

  15. Adaptive backstepping control, synchronization and circuit simulation of a 3-D novel jerk chaotic system with two hyperbolic sinusoidal nonlinearities

    Directory of Open Access Journals (Sweden)

    Vaidyanathan Sundarapandian

    2014-09-01

    Full Text Available In this research work, a six-term 3-D novel jerk chaotic system with two hyperbolic sinusoidal nonlinearities has been proposed, and its qualitative properties have been detailed. The Lyapunov exponents of the novel jerk system are obtained as L1 = 0.07765,L2 = 0, and L3 = −0.87912. The Kaplan-Yorke dimension of the novel jerk system is obtained as DKY = 2.08833. Next, an adaptive backstepping controller is designed to stabilize the novel jerk chaotic system with two unknown parameters. Moreover, an adaptive backstepping controller is designed to achieve complete chaos synchronization of the identical novel jerk chaotic systems with two unknown parameters. Finally, an electronic circuit realization of the novel jerk chaotic system using Spice is presented in detail to confirm the feasibility of the theoretical model

  16. TIPS Placement in Swine, Guided by Electromagnetic Real-Time Needle Tip Localization Displayed on Previously Acquired 3-D CT

    International Nuclear Information System (INIS)

    Solomon, Stephen B.; Magee, Carolyn; Acker, David E.; Venbrux, Anthony C.

    1999-01-01

    Purpose: To determine the feasibility of guiding a transjugular intrahepatic portosystemic shunt (TIPS) procedure with an electromagnetic real-time needle tip position sensor coupled to previously acquired 3-dimensional (3-D) computed tomography (CT) images. Methods: An electromagnetic position sensor was placed at the tip of a Colapinto needle. The real-time position and orientation of the needle tip was then displayed on previously acquired 3-D CT images which were registered with the five swine. Portal vein puncture was then attempted in all animals. Results: The computer calculated accuracy of the position sensor was on average 3 mm. Four of five portal vein punctures were successful. In the successes, only one or two attempts were necessary and success was achieved in minutes. Conclusion: A real-time position sensor attached to the tip of a Colapinto needle and coupled to previously acquired 3-D CT images may potentially aid in entering the portal vein during the TIPS procedure

  17. Assessing physiological tipping points in response to ocean acidification

    Science.gov (United States)

    Dupont, S. T.; Dorey, N.; Lançon, P.; Thorndyke, M. S.

    2011-12-01

    Impact of near-future ocean acidification on marine invertebrates was mostly assessed in single-species perturbation experiment. Moreover, most of these experiments are short-term, only consider one life-history stage and one or few parameters. They do not take into account important processes such as natural variability and acclimation and evolutionary processes. In many studies published so far, there is a clear lack between the observed effects and individual fitness, most of the deviation from the control being considered as potentially negative for the tested species. However, individuals are living in a fluctuating world and changes can also be interpreted as phenotypic plasticity and may not translate into negative impact on fitness. For example, a vent mussel can survive for decades in very acidic waters despite a significantly reduced calcification compare to control (Tunnicliffe et al. 2009). This is possible thanks to the absence of predatory crabs as a result of acidic conditions that may also inhibit carapace formation. This illustrates the importance to take into account ecological interactions when interpreting single-species experiments and to consider the relative fitness between interacting species. To understand the potential consequence of ocean acidification on any given ecosystem, it is then critical to consider the relative impact on fitness for every interactive species and taking into account the natural fluctuation in environment (e.g. pH, temperature, food concentration, abundance) and discriminate between plasticity with no direct impact on fitness and teratology with direct consequence on survival. In this presentation, we will introduce the concept of "physiological tipping point" in the context of ocean acidification. This will be illustrated by some work done on sea urchin development. Embryos and larvae of the sea urchin Strongylocentrotus droebachiensis were exposed to a range of pH from 8.1 to 6.5. When exposed to low pH, growth

  18. 3D palmprint and hand imaging system based on full-field composite color sinusoidal fringe projection technique.

    Science.gov (United States)

    Zhang, Zonghua; Huang, Shujun; Xu, Yongjia; Chen, Chao; Zhao, Yan; Gao, Nan; Xiao, Yanjun

    2013-09-01

    Palmprint and hand shape, as two kinds of important biometric characteristics, have been widely studied and applied to human identity recognition. The existing research is based mainly on 2D images, which lose the third-dimensional information. The biological features extracted from 2D images are distorted by pressure and rolling, so the subsequent feature matching and recognition are inaccurate. This paper presents a method to acquire accurate 3D shapes of palmprint and hand by projecting full-field composite color sinusoidal fringe patterns and the corresponding color texture information. A 3D imaging system is designed to capture and process the full-field composite color fringe patterns on hand surface. Composite color fringe patterns having the optimum three fringe numbers are generated by software and projected onto the surface of human hand by a digital light processing projector. From another viewpoint, a color CCD camera captures the deformed fringe patterns and saves them for postprocessing. After compensating for the cross talk and chromatic aberration between color channels, three fringe patterns are extracted from three color channels of a captured composite color image. Wrapped phase information can be calculated from the sinusoidal fringe patterns with high precision. At the same time, the absolute phase of each pixel is determined by the optimum three-fringe selection method. After building up the relationship between absolute phase map and 3D shape data, the 3D palmprint and hand are obtained. Color texture information can be directly captured or demodulated from the captured composite fringe pattern images. Experimental results show that the proposed method and system can yield accurate 3D shape and color texture information of the palmprint and hand shape.

  19. [Predictable tip suture techniques in rhinoplasty].

    Science.gov (United States)

    Papel, I D

    2010-09-01

    Recontouring the nasal tip in rhinoplastic procedures has generated a wide range of surgical techniques. These range from aggressive cartilage resection, division, grafting, or suture methods. Each of these categories contains many variations described in hundreds of publications. The goal of this communication is to describe a predictable, reproducible technique that can be used in a wide variety of rhinoplasty operations. Based on pre-existing anatomy variations of this technique can be adopted. The author described the basic technique in 2004 [1].The cornerstone of the technique is a predictable method of narrowing the interdomal space utilizing a suture technique. This procedure employs a pair of permanent sutures designed to minimize distortion, valve impingement and overcorrection. It can be performed through intranasal or external approaches. This paper will define the wide interdomal space, describe the technique, and demonstrate the efficacy of the technique in 250 rhinoplasty procedures. In addition, variations of the technique for specific goals will be shown.

  20. Twelve tips for developing an integrated curriculum.

    Science.gov (United States)

    Malik, Alam Sher; Malik, Rukhsana Hussain

    2011-01-01

    Integration of curriculum is meant to make the teaching/learning activities meaningful; however, the interpretation of 'integration' varies in different institutions and among individuals. Many medical schools find it hard to change their existing curriculum or develop a new integrated curriculum mainly because of lack of will, infrastructure and understanding the process of change. Drawn from experience, these 12 tips relating to staff development, establishing working groups, organizing the teaching/learning materials under themes and developing some innovative teaching/learning and assessment strategies, are the techniques that a teaching institution can use to change the existing curriculum to an integrated one or develop a new curriculum. Knowing about the different levels of integration and steps for developing an integrated curriculum can make it easier to integrate an existing curriculum or develop a new one.