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Sample records for vicinal torsion angle

  1. Anthropometric study of angle of femoral torsion in Maharashtrian population

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    Anil Kumar Dwivedi

    2016-01-01

    Full Text Available Introduction: Angle of femoral torsion is a normal torsion or twist present in femur that plays an important role in stability and function of the hip joint. The angle of femoral torsion can be defined as the angle formed by femoral condyle′s plane (bicondylar plane and a plane passing through center of neck and femoral head. Abnormal angle of femoral torsion has been implicated in the etiology of hip osteoarthrosis and developmental dysplasia of hip joint. Materials and Methods: This study was carried out on unpaired 280, adult human femora devoid of any gross pathology, 139 male (65 right and 74 left, and 141 female (71 right and 70 left from bone banks of three medical colleges of Maharashtra. The gender of each specimen was determined by the established practice. Femora were evaluated by Kingsley Olmsted method, and data were tabulated and statistically analyzed. Results: The average angle of femoral torsion 13.39° and 11.23° on the right and left side respectively in male, 16.21° and 13.23° on the right and left side, respectively, in female. Statistical analysis using Student′s "t"-test revealed significant difference (P < 0.05, greater angle of femoral torsion in female and on the right side. Conclusion: Knowledge of angle of femoral torsion is becoming significant nowadays with an increase in demand for total hip replacement, as the angle of femoral torsion is crucial to attain a normal activity of the replaced joint.

  2. Deep learning methods for protein torsion angle prediction.

    Science.gov (United States)

    Li, Haiou; Hou, Jie; Adhikari, Badri; Lyu, Qiang; Cheng, Jianlin

    2017-09-18

    Deep learning is one of the most powerful machine learning methods that has achieved the state-of-the-art performance in many domains. Since deep learning was introduced to the field of bioinformatics in 2012, it has achieved success in a number of areas such as protein residue-residue contact prediction, secondary structure prediction, and fold recognition. In this work, we developed deep learning methods to improve the prediction of torsion (dihedral) angles of proteins. We design four different deep learning architectures to predict protein torsion angles. The architectures including deep neural network (DNN) and deep restricted Boltzmann machine (DRBN), deep recurrent neural network (DRNN) and deep recurrent restricted Boltzmann machine (DReRBM) since the protein torsion angle prediction is a sequence related problem. In addition to existing protein features, two new features (predicted residue contact number and the error distribution of torsion angles extracted from sequence fragments) are used as input to each of the four deep learning architectures to predict phi and psi angles of protein backbone. The mean absolute error (MAE) of phi and psi angles predicted by DRNN, DReRBM, DRBM and DNN is about 20-21° and 29-30° on an independent dataset. The MAE of phi angle is comparable to the existing methods, but the MAE of psi angle is 29°, 2° lower than the existing methods. On the latest CASP12 targets, our methods also achieved the performance better than or comparable to a state-of-the art method. Our experiment demonstrates that deep learning is a valuable method for predicting protein torsion angles. The deep recurrent network architecture performs slightly better than deep feed-forward architecture, and the predicted residue contact number and the error distribution of torsion angles extracted from sequence fragments are useful features for improving prediction accuracy.

  3. Torsional Angle Driver (TorAD) System for HyperChem/Excel

    Science.gov (United States)

    Starkey, Ronald

    1999-02-01

    The torsional angle driver system for HyperChem/Excel is a package of several Excel spreadsheets and macro programs to be used with HyperChem to obtain and plot information, such as total energy, for the conformations that result from a 360° rotation about a torsional angle system in a molecule. The TorAD system also includes several HyperChem scripts to facilitate its use. TorAD was developed for use in the undergraduate organic chemistry laboratory. The results obtained with TorAD could be obtained manually with HyperChem, but it would take considerable time and would not be instructive to the students. Use of the TorAD system allows students to spend their time on the more important aspect of conformation analysisinterpretation of results. The Excel spreadsheet/macro programs in TorAD include: · Tor_xl_a and tor_xl obtain and plot the total energy at 5° torsional-angle intervals. The calculation method, the torsional-angle restraint, and the structure to be used at each angle can be set by the user. The advanced version, tor_xl_a, which requires HyperChem 4.5 or later, also allows torsional-angle structures to be saved for later recall as individual structures or, using a HyperChem script, in a movie format. It also provides a rapid scan of the 360° rotation where only single-point calculations, rather than geometry optimizations, are performed. The tor_xl system will perform routine tasks in a manner suitable for most instructional settings. · Tor_Comp performs molecular mechanics optimizations at 5° intervals and obtains and plots four energy parameters (total, torsional, nonbonded, and bond [bend plus stretch] energy) as a function of torsional angle. The calculation method and the restraint can be specified. · TorDipol produces a plot of the total energy and the calculated dipole moment at 5° steps of the torsional angle. The default calculation is the semi-empirical AM1 method, but other methods can be used. The calculation method and the restraint

  4. A laser speckle sensor to measure the distribution of static torsion angles of twisted targets

    DEFF Research Database (Denmark)

    Rose, B.; Imam, H.; Hanson, Steen Grüner

    1998-01-01

    A novel method for measuring the distribution of static torsion angles of twisted targets is presented. The method is based on Fourier transforming the scattered field in the direction perpendicular to the twist axis, while performing an imaging operation in the direction parallel to the axis....... A cylindrical lens serves to image the closely spaced lateral positions of the target along the twist axis onto corresponding lines of the two dimensional image sensor. Thus, every single line of the image sensor measures the torsion angle of the corresponding surface position along the twist axis of the target....... Experimentally, we measure the distribution of torsion angles in both uniform and non-uniform deformation zones. It is demonstrated both theoretically and experimentally that the measurements are insensitive to object shape and target distance if the image sensor is placed in the Fourier plane. A straightforward...

  5. Reliability and validity of measures of hammer toe deformity angle and tibial torsion.

    Science.gov (United States)

    Kwon, O Y; Tuttle, L J; Commean, P K; Mueller, M J

    2009-09-01

    Measures of second-fourth metatarsophalangeal joint (MTPJ) angle (indicator of hammer toe deformity) and clinical measures of tibial torsion have limited evidence for validity and reliability. The purposes of this study are to determine: (1) reliability of using a 3D digitizer (Metrecom) and computed tomography (CT) to measure MTPJ angle for toes 2-4; (2) reliability of goniometer, 3D digitizer, and CT to measure tibial torsion; (3) validity of MTPJ angle measures for toes 2-4 using goniometry and 3D digitizer compared to CT (gold standard) and (4) validity of tibial torsion measures using goniometry and 3D digitizer (Metrecom) compared to CT (gold standard). Twenty-nine subjects participated in this study. 27 feet with hammer toe deformity and 31 feet without hammer toe deformity were tested using standardized gonimetric, 3D digitizer and CT methods. ICCs (3,1), standard error of the measurement (SEM) values, and difference measures were used to characterize intrarater reliability. Pearson correlation coefficients and an analysis of variance were used to determine associations and differences between the measurement techniques. 3D digitizer and CT measures of MTPJ angle had high test-retest reliability (ICC = 0.95-0.96 and 0.98-0.99, respectively; SEM = 2.64-3.35 degrees and 1.42-1.47 degrees, respectively). Goniometry, 3D digitizer, and CT measures of tibial torsion had good test-retest reliability (ICC = 0.75, 0.85, and 0.98, respectively; SEM = 2.15 degrees, 1.74 degrees, and 0.72 degree, respectively). Both goniometric and 3D digitizer measures of MTPJ angle were highly correlated with CT measures of MTPJ angle (r = 0.84-0.90, r = 0.84-0.88, respectively) and tibial torsion (r = 0.72, r = 0.83). Goniometry, 3D digitizer, and CT measures were all different from each other for measures of hammer toe deformity (p Goniometry measures were different from CT measures and 3D digitizer measures of tibial torsion (p reliable. Goniometer and 3D digitizer measures of

  6. Determination of Femoral Neck Angle and Torsion Angle Utilizing a Novel Three-Dimensional Modeling and Analytical Technology Based on CT Datasets.

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    Maximilian J Hartel

    Full Text Available Exact knowledge of femoral neck inclination and torsion angles is important in recognizing, understanding and treating pathologic conditions in the hip joint. However, published results vary widely between different studies, which indicates that there are persistent difficulties in carrying out exact measurements.A three dimensional modeling and analytical technology was used for the analysis of 1070 CT datasets of skeletally mature femurs. Individual femoral neck angles and torsion angles were precisely computed, in order to establish whether gender, age, body mass index and ethnicity influence femoral neck angles and torsion angles.The median femoral neck angle was 122.2° (range 100.1-146.2°, IQR 117.9-125.6°. There are significant gender (female 123.0° vs. male 121.5°; p = 0.007 and ethnic (Asian 123.2° vs. Caucasian 121.9°; p = 0.0009 differences. The median femoral torsion angle was 14.2° (-23.6-48.7°, IQR 7.4-20.4°. There are significant gender differences (female 16.4° vs. male 12.1°; p = 0.0001. Femoral retroversion was found in 7.8% of the subjects.Precise femoral neck and torsion angles were obtained in over one thousand cases. Systematic deviations in measurement due to human error were eliminated by using automated high accuracy morphometric analysis. Small but significant gender and ethnic differences were found in femoral neck and torsion angles.

  7. Non Invasive Estimation of Left VentrNon Invasive Estimation of Left Ventricular Normalized Torsion Angle in Healthy Persons by Echo Tracking Algorithm: Short Axis Viewicular Normalized Torsion Angle in Healthy Persons by Echo Tracking Algorithm: Short Axis View

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    Zahra Arab Baferani

    2011-12-01

    Full Text Available Background: Left ventricular (LV torsion angle is a key parameter of cardiac performance but is difficult to measure. The purpose of this study is to describe a noninvasive imaging method for the assessment of these complex cardiac motions. Objectives: In this study, left ventricular torsion angle and normalized torsion angle were estimated in the short axis view for healthy persons. Patients and Methods: We acquired basal and apical short axis left ventricular LV images in the short axis view for 14 healthy men to estimate LV torsion angle by echo tracking under a block-matching (BM algorithm. By extracting the instantaneous changes in total displacement vector in the short axis view throughout a cardiac cycle, we calculated the instantaneous rotation and torsion angles in the short axis view. To account for differences in heart size, normalized torsion was calculated based on the radius of both the apical and basal slices in the end diastolic frame. Results: Apical and basal rotation was measured from short axis images by automatic frame-to-frame tracking of grayscale echo patterns. The vertical and horizontal displacements of the apical level were more than those of the basal level. All data are expressed as mean ± standard deviation (SD. Data was tested for normal distribution and homogeneity of variance by the Kolmogorov-Smirnov test (K-S and Levene’s test respectively. The peak rotation angles of the basal and apical levels and LV torsion angle in the short axis view were 8.0 ± 1.6°, 9.5 ± 1.8°, and 17.3 ± 2.5°, respectively. The normalized torsion was calculated as 7.8 ± 1.3°, based on the basal maximum radius, the apical maximum radius, and the distance between the apical and basal levels. Conclusions: We conclude that the normalized torsion angle is an important biomechanical parameter, because it is independent of heart size and distorted geometries in pathological ventricles.

  8. Sources of and Solutions to Problems in the Refinement of Protein NMR Structures against Torsion Angle Potentials of Mean Force

    Science.gov (United States)

    Kuszewski, John; Clore, G. Marius

    2000-10-01

    It is often the case that a substantial number of torsion angles (both backbone and sidechain) in structures of proteins and nucleic acids determined by NMR are found in physically unlikely and energetically unfavorable conformations. We have previously proposed a database-derived potential of mean force comprising one-, two-, three-, and four-dimensional potential surfaces which describe the likelihood of various torsion angle combinations to bias conformational sampling during simulated annealing refinement toward those regions that are populated in very high resolution (≤1.75 Å) crystal structures. We now note a shortcoming of our original implementation of this approach: namely, the forces it places on atoms are very rough. When the density of experimental restraints is low, this roughness can both hinder convergence to commonly populated regions of torsion angle space and reduce overall conformational sampling. In this paper we describe a modification that completely eliminates these problems by replacing the original potential surfaces by a sum of multidimensional Gaussian functions. Structures refined with the new Gaussian implementation now simultaneously enjoy excellent global sampling and excellent local choices of torsion angles.

  9. Conformational response of the phosphatidylcholine headgroup to bilayer surface charge: torsion angle constraints from dipolar and quadrupolar couplings in bicelles.

    Science.gov (United States)

    Semchyschyn, Darlene J; Macdonald, Peter M

    2004-02-01

    The effects of bilayer surface charge on the conformation of the phosphocholine group of phosphatidylcholine were investigated using a torsion angle analysis of quadrupolar and dipolar splittings in, respectively, (2)H and (13)C NMR spectra of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) labelled in the phosphocholine group with either deuterons (POPC-alpha-d(2), POPC-beta-d(2) and POPC-gamma-d(9)) or carbon-13 (POPC-alpha-(13)C and POPC-alphabeta-(13)C(2)) and incorporated into magnetically aligned bicelles containing various amounts of either the cationic amphiphile 1,2-dimyristoyl-3-trimethylammoniumpropane (DMTAP) or the anionic amphiphile 1,2-dimyristoyl-sn-glycero-3-phosphoglycerol (DMPG). Three sets of quadrupolar splittings, one from each of the three deuteron labelling positions, and three sets of dipolar splittings ((13)C(alpha)-(31)P, (13)C(alpha)-(13)C(beta), (13)C(beta)-(14)N), were measured at each surface charge, along with the (31)P residual chemical shift anisotropy. The torsion angle analysis assumed fast anisotropic rotation of POPC about its long molecular axis, thus projecting all NMR interactions onto that director axis of motion. Dipolar, quadrupolar and chemical shift anisotropies were calculated as a function of the phosphocholine internal torsion angles by first transforming into a common reference frame affixed to the phosphocholine group prior to motional averaging about the director axis. A comparison of experiment and calculation provided the two order parameters specifying the director orientation relative to the molecule, plus the torsion angles alpha(3), alpha(4) and alpha(5). Surface charge was found to have little effect on the torsion angle alpha(5) (rotations about C(alpha)-C(beta)), but to have large and inverse effects on torsion angles alpha(3) [rotations about P-O(11)] and alpha(4) [rotations about O(11)-C(alpha)], yielding a net upwards tilt of the P-N vector in the presence of cationic surface charge, and a

  10. Determination of magnetic anisotropies and miscut angles in epitaxial thin films on vicinal (111) substrate by the ferromagnetic resonance

    Science.gov (United States)

    Belyaev, B. A.; Izotov, A. V.; Solovev, P. N.; Yakovlev, I. A.

    2017-10-01

    A method for determining magnetic anisotropy parameters of a thin single-crystal film on vicinal (111) substrate as well as substrate miscut angles from angular dependence of ferromagnetic resonance field has been proposed. The method is based on the following: (i) a new approach for the solution of the system of nonlinear equations for equilibrium and resonance conditions; (ii) a new expression of the objective function for the fitting problem. The study of the iron silicide films grown on vicinal Si(111) substrates with different miscut angles confirmed the efficiency of the method. The proposed method can be easily generalized to determine parameters of single-crystal films grown on substrates with an arbitrary cut.

  11. Combined Monte Carlo/torsion-angle molecular dynamics for ensemble modeling of proteins, nucleic acids and carbohydrates.

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    Zhang, Weihong; Howell, Steven C; Wright, David W; Heindel, Andrew; Qiu, Xiangyun; Chen, Jianhan; Curtis, Joseph E

    2017-05-01

    We describe a general method to use Monte Carlo simulation followed by torsion-angle molecular dynamics simulations to create ensembles of structures to model a wide variety of soft-matter biological systems. Our particular emphasis is focused on modeling low-resolution small-angle scattering and reflectivity structural data. We provide examples of this method applied to HIV-1 Gag protein and derived fragment proteins, TraI protein, linear B-DNA, a nucleosome core particle, and a glycosylated monoclonal antibody. This procedure will enable a large community of researchers to model low-resolution experimental data with greater accuracy by using robust physics based simulation and sampling methods which are a significant improvement over traditional methods used to interpret such data. Published by Elsevier Inc.

  12. Effect of Relative Marker Movement on the Calculation of the Foot Torsion Axis Using a Combined Cardan Angle and Helical Axis Approach

    Directory of Open Access Journals (Sweden)

    Eveline S. Graf

    2012-01-01

    Full Text Available The two main movements occurring between the forefoot and rearfoot segment of a human foot are flexion at the metatarsophalangeal joints and torsion in the midfoot. The location of the torsion axis within the foot is currently unknown. The purpose of this study was to develop a method based on Cardan angles and the finite helical axis approach to calculate the torsion axis without the effect of flexion. As the finite helical axis method is susceptible to error due to noise with small helical rotations, a minimal amount of rotation was defined in order to accurately determine the torsion axis location. Using simulation, the location of the axis based on data containing noise was compared to the axis location of data without noise with a one-sample t-test and Fisher's combined probability score. When using only data with helical rotation of seven degrees or more, the location of the torsion axis based on the data with noise was within 0.2 mm of the reference location. Therefore, the proposed method allowed an accurate calculation of the foot torsion axis location.

  13. Effect of Relative Marker Movement on the Calculation of the Foot Torsion Axis Using a Combined Cardan Angle and Helical Axis Approach

    Science.gov (United States)

    Graf, Eveline S.; Wright, Ian C.; Stefanyshyn, Darren J.

    2012-01-01

    The two main movements occurring between the forefoot and rearfoot segment of a human foot are flexion at the metatarsophalangeal joints and torsion in the midfoot. The location of the torsion axis within the foot is currently unknown. The purpose of this study was to develop a method based on Cardan angles and the finite helical axis approach to calculate the torsion axis without the effect of flexion. As the finite helical axis method is susceptible to error due to noise with small helical rotations, a minimal amount of rotation was defined in order to accurately determine the torsion axis location. Using simulation, the location of the axis based on data containing noise was compared to the axis location of data without noise with a one-sample t-test and Fisher's combined probability score. When using only data with helical rotation of seven degrees or more, the location of the torsion axis based on the data with noise was within 0.2 mm of the reference location. Therefore, the proposed method allowed an accurate calculation of the foot torsion axis location. PMID:22666303

  14. Determination of the torsion angles of alanine and glycine residues of model compounds of spider silk (AGG){sub 10} using solid-state NMR methods

    Energy Technology Data Exchange (ETDEWEB)

    Ashida, Jun; Ohgo, Kosuke; Komatsu, Kohei; Kubota, Ayumi; Asakura, Tetsuo [Tokyo University of Agriculture and Technology, Department of Biotechnology (Japan)], E-mail: asakura@cc.tuat.ac.jp

    2003-02-15

    Spiders synthesize several kinds of silk fibers. In the primary structure of spider silk, one of the major ampullate (dragline, frame) silks, spidroin 1, and flagelliform silk (core fibers of adhesive spiral), there are common repeated X-Gly-Gly (X = Ala, Leu, Pro, Tyr, Glu, and Arg) sequences, which are considered to be related to the elastic character of these fibers. In this paper, two dimensional spin diffusion solid-state NMR under off magic angle spinning (OMAS), {sup 13}C chemical shift contour plots, and Rotational Echo DOuble Resonance (REDOR) were applied to determine the torsion angles of one Ala and two kinds of Gly residues in the Ala-Gly-Gly sequence of {sup 13}C=O isotope-labeled (Ala-Gly-Gly){sub 10}. The torsion angles were determined to be ({phi}, {psi}) = (-90 deg., 150 deg.) within an experimental error of {+-}10 deg. for each residue. This conformation is characterized as 3{sub 1} helix which is in agreement with the structure proposed from the X-ray powder diffraction pattern of poly(Ala-Gly-Gly). The 3{sub 1} helix of (Ala-Gly-Gly){sub 10} does not change by formic acid treatment although (Ala-Gly){sub 15} easily changes from the silk I conformation (the structure of Bombyx mori silk fibroin before spinning in the solid state) to silk II conformation (the structure of the silk fiber after spinning) by such treatment. Thus, the 3{sub 1} helix conformation of (Ala-Gly-Gly){sub 10} is considered very stable. Furthermore, the torsion angles of the 16th Leu residue of (Leu-Gly-Gly){sub 10} were also determined as ({phi}, {psi}) = (-90 deg., 150 deg.) and this peptide is also considered to take 3{sub 1} helix conformation.

  15. Dynamical torsion and torsion potential

    OpenAIRE

    Xie, Hong-Jun; Shirafuji, Takeshi

    1996-01-01

    We introduce a generalized tetrad which plays the role of a potential for torsion and makes torsion dynamic. Starting from the Einstein-Cartan action with torsion, we get two field equations, the Einstein equation and the torsion field equation by using the metric tensor and the torsion potential as independent variables; in the former equation the torsion potential plays the role of a matter field. We also discuss properties of local linear transformations of the torsion potential and give a...

  16. Singular value decomposition analysis of the torsional angles of dopamine reuptake inhibitor GBR 12909 analogs: effect of force field and charges.

    Science.gov (United States)

    Pandit, Deepangi; Fiorentino, Anna; Bindra, Supreet; Venanzi, Carol A

    2011-06-01

    Three-dimensional quantitative structure-activity relationship (3D-QSAR) analysis of large, flexible molecules, such as the dopamine reuptake inhibitor GBR 12909 (1), is complicated by the fact that they can take on a wide range of closely-related conformations. The first step in the analysis is to classify the conformers into groups. Over 600 conformers each of a piperazine (2) and piperidine (3) analog of 1 were generated by random search conformational analysis using the Merck Molecular Force Field (MMFF94). Singular value decomposition (SVD) was used to group the conformers of 2 and 3 by the similarity of their non-ring torsional angles. SVD uncovered subtle differences in their conformer populations due to that fact that the conformers separate along different principal components, and ultimately to the fact that different torsional angles are the chief contributors to these components. The results were compared to our previous SVD analysis (Fiorentino, et al., Journal of Computational Chemistry, 2006, 27, 609-620) of conformer populations of 2 and 3 generated by the Tripos force field and Gasteiger-Hückel charges. Except for the dominant contribution of angle B3 to principal component 8 seen with both force fields, the angles which are chiefly responsible for the grouping of the conformers of 2 and 3 are different with both force fields. This illustrates that SVD is useful in identifying unique groupings of conformers in large data sets of flexible molecules-a first step in selecting representative conformers for 3D-QSAR modeling studies.

  17. Measuring the {chi}{sub 1} torsion angle in protein by CH-CH cross-correlated relaxation: A new resolution-optimised experiment

    Energy Technology Data Exchange (ETDEWEB)

    Carlomagno, Teresa [Max Planck Institute for Biophysical Chemistry, Department of NMR-based Structural Biology (Germany)], E-mail: taco@nmr.mpibpc.mpg.de; Bermel, Wolfgang [Bruker Biospin GmbH (Germany); Griesinger, Christian [Max Planck Institute for Biophysical Chemistry, Department of NMR-based Structural Biology (Germany)], E-mail: cigr@nmr.mpibpc.mpg.de

    2003-10-15

    Here we introduce an experiment with high sensitivity and resolution for the measurement of CH-CH dipolar-dipolar cross-correlated relaxation rates (CCRR) in protein side-chains. The new methodology aims to the determination of structural and dynamical parameters around the torsion angle {chi}{sub 1} by measuring C{sub {alpha}}H{sub {alpha}}-C{sub {beta}}H{sub {beta}} cross-correlated relaxation rates. The method is validated on the protein ubiquitin: the {chi}{sub 1} angles determined from the CCRR data are compared with the {chi}{sub 1} angles of a previously determined NMR structure. The agreement between the two data sets is excellent for most residues. The few discrepancies that were found between the CCR-derived {chi}{sub 1} angles and the angles of the previously determined NMR structure could be explained by taking internal motion into account. The new methodology represents a very powerful tool to determine both structure and dynamics of protein side-chains in only one experiment.

  18. Torsion pendulum revisited

    Energy Technology Data Exchange (ETDEWEB)

    Bassan, Massimo [Dipartimento di Fisica, Università di Roma Tor Vergata, and INFN, Sezione di Roma Tor Vergata, I-00133 Roma (Italy); De Marchi, Fabrizio, E-mail: fabrizio.demarchi@roma2.infn.it [Dipartimento di Fisica, Università di Roma Tor Vergata, and INFN, Sezione di Roma Tor Vergata, I-00133 Roma (Italy); Marconi, Lorenzo [Dipartimento di Fisica ed Astronomia, Università degli Studi di Firenze, and INFN, Sezione di Firenze (Italy); Pucacco, Giuseppe [Dipartimento di Fisica, Università di Roma Tor Vergata, and INFN, Sezione di Roma Tor Vergata, I-00133 Roma (Italy); Stanga, Ruggero [Dipartimento di Fisica ed Astronomia, Università degli Studi di Firenze, and INFN, Sezione di Firenze (Italy); Visco, Massimo [IAPS-INAF, and INFN, Sezione di Roma Tor Vergata, I-00133 Roma (Italy)

    2013-10-01

    We present an analysis of the motion of a simple torsion pendulum and we describe how, with straightforward extensions to the usual basic dynamical model, we succeed in explaining some unexpected features we found in our data, like the modulation of the torsion mode at a higher frequency and the frequency splitting of the swinging motion. Comparison with observed values yields estimates for the misalignment angles and other parameters of the model.

  19. DNA minor groove electrostatic potential: influence of sequence-specific transitions of the torsion angle gamma and deoxyribose conformations.

    Science.gov (United States)

    Zhitnikova, M Y; Shestopalova, A V

    2017-11-01

    The structural adjustments of the sugar-phosphate DNA backbone (switching of the γ angle (O5'-C5'-C4'-C3') from canonical to alternative conformations and/or C2'-endo → C3'-endo transition of deoxyribose) lead to the sequence-specific changes in accessible surface area of both polar and non-polar atoms of the grooves and the polar/hydrophobic profile of the latter ones. The distribution of the minor groove electrostatic potential is likely to be changing as a result of such conformational rearrangements in sugar-phosphate DNA backbone. Our analysis of the crystal structures of the short free DNA fragments and calculation of their electrostatic potentials allowed us to determine: (1) the number of classical and alternative γ angle conformations in the free B-DNA; (2) changes in the minor groove electrostatic potential, depending on the conformation of the sugar-phosphate DNA backbone; (3) the effect of the DNA sequence on the minor groove electrostatic potential. We have demonstrated that the structural adjustments of the DNA double helix (the conformations of the sugar-phosphate backbone and the minor groove dimensions) induce changes in the distribution of the minor groove electrostatic potential and are sequence-specific. Therefore, these features of the minor groove sizes and distribution of minor groove electrostatic potential can be used as a signal for recognition of the target DNA sequence by protein in the implementation of the indirect readout mechanism.

  20. (2S,4R)-4-hydroxyproline(4-nitrobenzoate): strong induction of stereoelectronic effects via a readily synthesized proline derivative. Crystallographic observation of a correlation between torsion angle and bond length in a hyperconjugative interaction.

    Science.gov (United States)

    Pandey, Anil K; Yap, Glenn P A; Zondlo, Neal J

    2014-05-02

    (2S,4R)-4-Hydroxyproline(4-nitrobenzoate) was synthesized. The crystal structure revealed an exo ring pucker, with the nitrobenzoate pseudoaxial on the pyrrolidine envelope and antiperiplanar to C(β) and C(δ) C-H bonds. The unit cell exhibited variation in C(δ)-H/C(γ)-O and C(β)-H/C(γ)-O torsion angles, with a 15° increase in torsion angle (148° to 163°) observed to result in a 0.018 Å decrease in C(δ)-H/C(γ)-O bond length, consistent with favorable σC-H → σ*C-O hyperconjugative interactions increasing with greater orbital overlap.

  1. Appendicular Torsion

    Directory of Open Access Journals (Sweden)

    Siddharth Pramod Dubhashi

    2016-01-01

    Full Text Available Torsion of the vermiform appendix is a rare condition detectable only at operation. It can be primary or secondary. This is a case report of 52-year-old female with 180° anti-clockwise rotation of the appendix. Torsion can further leads to strangulation and infarction of the organ. Appendicular torsion could be included in the differential diagnosis of pain in right iliac fossa.

  2. Appendicular Torsion

    African Journals Online (AJOL)

    [4] It can be primary or subsequent to other pathological conditions like faecolith, mucocele, carcinoid tumor or ... KEYWORDS: Anti‑clockwise, appendix, primary, secondary, torsion. This is an open access article ... Valenciano‑Fuentes B. Torsion of vermiform appendix: Value of ultrasonographic findings. Eur J Pediatr Surg ...

  3. Testicular Torsion

    Science.gov (United States)

    ... Campbell-Walsh Urology. 10th ed. Philadelphia, Pa.: Saunders Elsevier; 2012. http://www.clinicalkey.com. Accessed Feb. 13, 2015. Somani BK, et al. Testicular torsion. BMJ. 2010;341:c3213. Cubillos J, et al. Familial testicular torsion. Journal of Urology. 2011;185:2469. Hittelman AB. Neonatal ...

  4. TESTICULAR TORSION:

    African Journals Online (AJOL)

    TESTICULAR TORSION: EXPERIENCE IN THE MIDDLE BELT OF NIGERIA. S.A. KURANGA AND G.A. RAHMAN. Department of Surgery, University of l/orin Teaching Hospital, Ilorin, Nigeria. Objective To determine the fate of the testis affected by testicular torsion (TT) in relation to the duration of the symptoms and to.

  5. Tibial Torsion Among Filipinos: A Cadaveric Study

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    Villamin CAC

    2012-07-01

    Full Text Available Tibial torsion, the twisting of the tibia about its long axis, can affect rotational positioning in total knee replacement. This angle varies depending on the ethnicity of the subject. There are no published studies to date to determine the tibial torsion among Filipinos. In this study, 28 cadaveric limbs were examined. Our results show that the average tibial torsion among adult Filipinos is 28.9°.

  6. Testicular torsion

    DEFF Research Database (Denmark)

    Brasso, K; Andersen, L; Kay, L

    1993-01-01

    Thirty-five patients were examined 6-11 years after operation for torsion of the testis. Loss of testicular tissue was significantly associated with long preoperative duration of symptoms and with low postoperative sperm counts. The sex hormones were normal in the majority of patients but there w......Thirty-five patients were examined 6-11 years after operation for torsion of the testis. Loss of testicular tissue was significantly associated with long preoperative duration of symptoms and with low postoperative sperm counts. The sex hormones were normal in the majority of patients...

  7. Appendicular Torsion

    African Journals Online (AJOL)

    A‑2/103, Shivranjan Towers, Someshwarwadi, Pashan, Pune ‑ 411 008,. Maharashtra, India. E‑mail: spdubhashi@gmail.com. INTRODUCTION. Acute appendicitis presents with pain in right iliac fossa. Torsion of the vermiform appendix, though rare, also presents in a similar fashion, and it is detectable only at operation.[1].

  8. Tibiofibular torsion in congenital clubfoot.

    Science.gov (United States)

    Farsetti, Pasquale; Dragoni, Massimiliano; Ippolito, Ernesto

    2012-01-01

    Tibiofibular torsion was measured by computed tomography in three series of patients affected by congenital clubfoot who were treated with different protocols. The normal leg of unilateral deformities served as the control. For the bilateral cases, only the right side was included in the study. The angle between the bicondylar axis of the tibia and the bimalleolar axis was the index of tibiofibular torsion. There were 34 clubfeet in the first series, treated with a posteromedial release, and 40 clubfeet in the second series, treated with a modified Ponseti method, whereas the third series included 16 clubfeet, treated with the original Ponseti method. All 90 clubfeet were graded at birth as group 3 according to the Manes classification. No patient had previous treatment. The patients of the first and the second series were followed up to maturity, whereas the patients of the third series were followed up to a maximum of 11 years of age. In the congenital clubfoot, the tibia and the fibula were externally rotated, in comparison with the normal leg; in fact, the average value of the angle of tibiofibular torsion was 32.2° in the first series, 23.9° in the second series, and 21.1° in the third series. In the normal tibiae, the average value of the angle of tibiofibular torsion was 21.4°. The difference between the first series and the normal controls was statistically significant, as was the difference between the first one and the other two series. The value of the tibiofibular torsion angle seems to be related to the manipulation technique used to treat clubfoot: when the manipulation does not allow a progressive eversion of the talus underneath the calcaneus, the external tibial torsion increases. At follow-up, an intoeing gait was present in seven treated clubfeet of the first series. In all of them except one, the highest value of the external tibial torsion angle was observed, with a low value of the Kite's angle and/or residual forefoot adduction. In the

  9. 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

  10. Characterization of ZnO thin film grown on c-plane substrates by MO-CVD: Effect of substrate annealing temperature, vicinal-cut angle and miscut direction

    Science.gov (United States)

    Boukadhaba, M. A.; Fouzri, A.; Sallet, V.; Hassani, S. S.; Amiri, G.; Lusson, A.; Oumezzine, M.

    2015-09-01

    The annealing effects of c-plane sapphire (α-Al2O3) substrate with a nominally vicinal-cut angle α (α ZnO films grown by metal organic chemical vapor deposition (MO-CVD) were studied. The atomic steps formed on sapphire substrate surface by annealing at high temperature were analyzed by atomic force microscopy (AFM). The annealing and the miscut direction of sapphire substrate on the microstructural and optical properties for ZnO films were examined by high resolution X-ray diffraction (HR-XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM) and photoluminescence spectroscopy (PL). Experimental results indicate that the film quality is strongly affected by annealing treatment and miscut direction of the sapphire substrate. X-ray diffraction study revealed that all films exhibit a wurtzite phase and have a c-axis orientation. ZnO films deposited on sapphire substrate (α ZnO layer deposited on annealed sapphire substrate with increase the annealing substrate temperature for all samples. AFM image show significant differences between morphologies of samples depending on annealing treatment and miscut direction of substrates but no significant differences on surface roughness have been found. Sapphire annealing at 1100 °C with a nominally vicinal-cut angle α = 0.25° toward the m-plane (1 0 1 bar 0), provides the best optical quality of ZnO film.

  11. Multidimensional Seismic Control by Tuned Mass Damper with Poles and Torsional Pendulums

    National Research Council Canada - National Science Library

    Haoxiang He; Wentao Wang; Honggang Xu

    2017-01-01

    .... In order to simultaneously control the translational responses and the torsional angle of asymmetry structures, a new type of tuned mass damper with tuned mass blocks, orthogonal poles, and torsional pendulums (TMDPP) is proposed...

  12. Torsion and entropy driven denaturation of DNA

    Energy Technology Data Exchange (ETDEWEB)

    Roy, Subhamoy Singha, E-mail: ssroy.science@gmail.com [Department of Physics, JIS College of Engineering (Autonomous), West Bengal University of Technology, Kalyani, Nadia 741235 (India); Bandyopadhyay, Pratul, E-mail: b_pratul@yahoo.co.in [Physics and Applied Mathematics Unit, Indian Statistical Institute, 203 B.T. Road, Kolkata 700108 (India)

    2013-11-29

    A unified theory of the denaturation transition having torsion energy as the control parameter has been formulated here in the framework of the mapping of a DNA molecule onto a Heisenberg spin system. The torsion energy incorporates the torque, tension and temperature, the latter being associated with the twist angle. The denaturation transition can be mapped onto the quantum phase transition induced by a quench when the temperature effect is incorporated in the quench time and torsion takes the role of the external field. The denaturation transition occurs when the entanglement entropy of the spin system vanishes.

  13. Measurement of tibial torsion by computer tomography

    Energy Technology Data Exchange (ETDEWEB)

    Jend, H.H.; Heller, M.; Dallek, M.; Schoettle, H. (Hamburg Univ. (Germany, F.R.))

    1981-01-01

    A CT procedure for objective measurements of tibial torsion independent of axial rotation in the nearby joints is described. Transverse sections in defined planes of the tibia permit easy calculation of normal and abnormal congenital or posttraumatic angles of torsion. In 69 limbs normal tibial torsion was 40/sup 0/+-9/sup 0/. In a series of 42 limbs with complicated healing of a fracture of both bones of the leg it is shown that tibial maltorsion is a deformity which in most cases leads to arthrosis of the ankle joint.

  14. Severely deformed Cu by using compression with oscillatory torsion method

    OpenAIRE

    K. Rodak

    2007-01-01

    Purpose: The present study is aimed at a quantitative description of microstructural parameters as a misorientationangle of Cu deformed by using compression with oscillatory torsion.Design/methodology/approach: Cu samples were deformed at torsion frequency (f) changed from 0 Hz(compression only) to 1.8 Hz under a constant torsion angle (α) ≈ 8° and compression speed (v)=0.1mm/s.Structural investigations were conducted by using transmission electron microscopy (TEM). Local misorientationhave b...

  15. Influence of the Torsion Angle in 3,3'-Dimethyl-2,2'-bipyridine on the Intermediate Valence of Yb in (C5Me5)2 Yb(3,3'-Me2-bipy)

    Energy Technology Data Exchange (ETDEWEB)

    Nocton, Gr& #233; gory; Booth, Corwin H.; Maron, Laurent; Andersen, Richard A.

    2014-06-26

    The synthesis and X-ray crystal structures of Cp-2*Yb(3,3'-Me(2)bipy) and [Cp-2 Yb(3,3'-Me(2)bipy)][Cp-2 YbCl1.6I0.4]center dot CH2Cl2 are described. In both complexes, the NCCN torsion angles are approximately 40 degrees. The temperature-independent value of n(f) of 0.17 shows that the valence of ytterbium in the neutral adduct is multiconfigurational, in reasonable agreement with a CASSCF calculation that yields a n(f) value of 0.27; that is, the two configurations in the wave function are f(13)(pi(1))(1) and f(14)(pi(1))(0) in a ratio of 0.27:0.73, respectively, and the open-shell singlet lies 0.28 eV below the triplet state (n(f) accounts for f-hole occupancy; that is, n(f) = 1 when the configuration is f(13) and n(f) = 0 when the configuration is f(14)). A correlation is outlined between the value of nf and the individual ytterbocene and bipyridine fragments such that, as the reduction potentials of the ytterbocene cation and the free x,x'-R-2-bipy ligands approach each other, the value of nf and therefore the f(13):f(14) ratio reaches a maximum; conversely, the ratio is minimized as the disparity increases.

  16. Normal and abnormal torsional development in children.

    Science.gov (United States)

    Fabry, G; Cheng, L X; Molenaers, G

    1994-05-01

    This study presents findings in a series of 123 children with intoeing gait. The intoeing was caused by increased femoral anteversion (IFA) in 70% of the cases, and internal tibial torsion (ITT) in 30%. Rotation of the hips, thigh-foot angle, Q-angle, and computed tomography measured anteversion and tibial torsion divided the two groups very clearly. In the IFA group, 40.3% of the patients presented with an externally rotated tibia and 59.7% had an internally rotated tibia. In the ITT group, the anteversion was normal for age and the tibial torsion was significantly decreased. Eighty children who corrected their intoeing gait, and of whom 83.4% had IFA, were also reviewed: a decrease in anteversion was observed in 20.5% of the patients; 62.9% showed no decrease in anteversion.

  17. Investigation of the torsional stiffness of flexible disc coupling

    Science.gov (United States)

    Buryy, A.; Simonovsky, V.; Obolonik, V.

    2017-08-01

    Calculation of flexible coupling torsional stiffness is required when analyzing the torsional vibrations of the reciprocating machinery train. While having the lowest torsional stiffness of all the elements of the train, flexible coupling has a significant influence on the natural frequencies of torsional vibration. However, considering structural complexity of coupling, precise definition of its torsional stiffness is quite a difficult task. The paper presents a method for calculating the torsional stiffness of flexible disc coupling based on the study of its finite element model response under the action of torque. The analysis of the basic parameters that quantitatively and qualitatively affect the coupling torsional stiffness has been also provided. The results of the calculation as well as model adequacy, sufficient for practical application, have been confirmed at the experimental measurement of flexible disc coupling torsional stiffness. The obtained elastic characteristics (dependences of applied torque and torsional stiffness versus twist angle) are nonlinear in the initial stage of loading. This feature should be taken into account when creating reliable mathematical models of torsional vibrations of reciprocating machinery trains containing flexible disc couplings.

  18. [Correlation analysis on the disorders of patella-femoral joint and torsional deformity of tibia].

    Science.gov (United States)

    Sun, Zhen-Jie; Yuan, Yi; Liu, Rui-Bo

    2015-03-01

    To reveal the possible mechanism involved in patella-femoral degenerative arthritis (PFDA) in- duced by torsion-deformity of tibia via analyzing the relationship between torsion-deformity of the tibia in patients with PFDA and the disorder of patella-femoral joint under the static and dynamic conditions. From October 2009 to October 2010, 50 patients (86 knees, 24 knees of male patients and 62 knees of female patients) with PFDA were classified as disease group and 16 people (23 knees, 7 knees of males and 16 knees of females) in the control group. The follow indexes were measured: the torsion-angle of tibia on CT scanning imagings, the patella-femoral congruence angle and lateral patella-femoral angle under static and dynamic conditions when the knee bent at 30 degrees of flexion. Based on the measurement results, the relationship between the torsion-deformity of tibias and the disorders of patella-femoral joints in patients with PFDA were analyzed. Finally,the patients were divided into three groups including large torsion-angle group, small torsion-angle group and normal group according to the size of torsion-angle, in order to analyze the relationship between torsion-deformity and disorders of patella-femoral joint, especially under the dynamic conditions. Compared with patients without PFDA, the ones with PFDA had bigger torsion-angle (30.30 ± 7.11)° of tibia, larger patella-femoral congruence angle (13.20 ± 3.94)° and smaller lateral patella-femoral angle (12.30 ± 3.04)°. The congruence angle and lateral patella-femoral angle under static and dynamic conditions had statistical differences respectively in both too-big torsion-angle group and too-small torsion-angle group. The congruence angle and lateral patella-femoral angle under static and dynamic conditions had no statistical differences in normal torsion-angle group. Torsion-deformity of tibia is the main reason for disorder of patella-femoral joint in the patients with PFDA. Torsion-deformity of

  19. Postcesarean Splenic Torsion

    Directory of Open Access Journals (Sweden)

    Yu-Hui Huang

    2006-09-01

    Conclusion: Splenic torsion is a rare cause of acute abdominal pain during pregnancy or postpartum, and the symptoms vary depending on the degree of torsion. Early involvement of many complementary specialty services enabled early recognition of this rare entity and timely definitive treatment.

  20. Intermittent Testicular Torsion

    African Journals Online (AJOL)

    2017-12-05

    Dec 5, 2017 ... Objective: The aim of this study is to highlight the clinical characteristics of patients with intermittent testicular torsion and draw attention to this underreported condition. Methods: Clinical and demographic data of all patients treated for intermittent testicular torsion from January 2007 to June 2015 were ...

  1. Gallbladder torsion. Case report

    DEFF Research Database (Denmark)

    Brasso, K; Rasmussen, O V

    1991-01-01

    Gallbladder torsion is a rare surgical emergency occurring primarily in elderly women. The anatomical background is a variation in the attachment of the gallbladder to the inferior margin of the liver. Increasing life span will probably lead to an increasing number of cases, and gallbladder torsion...

  2. Humeral torsion and passive shoulder range in elite volleyball players.

    Science.gov (United States)

    Schwab, Laura M; Blanch, Peter

    2009-05-01

    To evaluate variations in humeral torsion in elite male volleyball players and determine whether these changes are related to training history, retrospective injury history and volleyball performance. Cross sectional design. Twenty-four elite male volleyball players. Humeral torsion, passive gleno-humeral rotation ranges and the available internal and external rotation from the humeral torsion neutral position of the dominant and non-dominant arm were measured. Training history and retrospective injury status were ascertained from a questionnaire. Performance was assessed by coach perceived spiking ability and peak serve velocity measures. Humeral torsion angles demonstrated the dominant arm to be on average 9.6 degrees more retroverted than the non-dominant arm (p=0.00). In the comparison of volleyball players with and without a history of overuse upper limb injury the most significant finding is on the non-dominant side, those with a history of injury had significantly decreased available external rotation from the humeral torsion neutral position (mean difference=-15.1, p=0.04). There was an unexpected negative weak relationship between age commenced and decreased humeral retroversion (r=-0.413, p=0.045). There did not appear to be any relationship between humeral torsion and performance measures. The dominant arm of elite male volleyball athletes is more retroverted. There was a tendency for stronger findings in the non-dominant arm in volleyball players with retrospective injury history. We were unable to find any significant correlation between humeral torsion angle and performance measures.

  3. Torsional Strengthening of RC Beams Using GFRP Composites

    Science.gov (United States)

    Patel, Paresh V.; Jariwala, Vishnu H.; Purohit, Sharadkumar P.

    2016-09-01

    Fiber reinforced polymer as an external reinforcement is used extensively for axial, flexural and shear strengthening in structural systems. The strengthening of members subjected to torsion is recently being explored. The loading mechanism of beams located at the perimeter of buildings which carry loads from slabs, joists and beams from one side of the member generates torsion that are transferred from the beams to the columns. In this work an experimental investigation on the improvement of the torsional resistance of reinforced concrete beams using Glass Fiber Reinforced Polymer (GFRP) is presented. Total 24 RC beams have been cast in this work. Ten beams of dimension 150 mm × 150 mm × 1300 mm are subjected to pure torsion while fourteen beams of 150 mm × 150 mm × 1700 mm are subjected to combined torsion and bending. Two beams in each category are designated as control specimen and remaining beams are strengthened by GFRP wrapping of different configurations. Pure torsion on specimens is applied using specially fabricated support mechanism and universal testing machine. For applying combined torsion and bending a loading frame and test set up are fabricated. Measurements of angle of twist at regular interval of torque, torsion at first crack, and ultimate torque, are obtained for all specimens. Results of different wrapping configurations are compared for control and strengthened beams to suggest effective GFRP wrapping configuration.

  4. Testicular torsion repair

    Science.gov (United States)

    ... male growth, sex life, and fertility. Patient Instructions Surgical wound care - open Images Male reproductive anatomy Testicular torsion repair - series References ... of the testes and scrotum and their surgical management. In: Wein AJ, ed. Campbell-Walsh Urology . ...

  5. Ultrafine grained Cu processed by compression with oscillatory torsion

    OpenAIRE

    K. Rodak

    2007-01-01

    Purpose: The aim of this work is a study of Cu microstructure after severe plastic deformation process by usingcompression with oscillatory torsion test.Design/methodology/approach: Cu samples were deformed at torsion frequency (f) changed from 0 Hz(compression) to 1.8 Hz under a constant torsion angle (α) ≈8° and compression speed (v)=0.1mm/s. Structuralinvestigations were conducted by using light microscopy (LM) and transmission electron microscopy (TEM).Findings: The structural analysis ma...

  6. Torsional vibration analysis of bars including secondary torsional shear deformation effect by the boundary element method

    Science.gov (United States)

    Sapountzakis, E. J.; Tsipiras, V. J.; Argyridi, A. K.

    2015-10-01

    In this paper a boundary element method (BEM) is developed for the torsional vibration problem of bars of arbitrary doubly symmetric constant cross section, taking into account the nonuniform warping and secondary torsional shear deformation effects (STSDE). The bar is subjected to arbitrarily distributed or concentrated dynamic torsional loading along its length, while its edges are subjected to the most general torsional and warping boundary conditions. Apart from the angle of twist, the primary angle of twist per unit length is considered as an additional 1-D degree of freedom in order to account for the STSDE in the equations of motion of the bar. The warping shear stress distribution and the pertinent secondary torsional rigidity are computed by satisfying local equilibrium considerations under dynamic conditions without adhering to assumptions of Thin Tube Theory (TTT). By employing a distributed mass model system accounting for rotatory and warping inertia, an initial boundary value and two boundary value problems with respect to the variable along the bar time-dependent 1-D kinematical components, to the primary and secondary warping functions, respectively, are formulated. The latter are solved employing a pure BE method, requiring exclusively boundary discretization of the bar's cross section. The numerical solution of the aforementioned initial boundary value problem is performed through a BE method leading to a system of differential equations with displacement only unknowns, which is solved using an efficient direct time integration technique. Additionally, for the free vibrations case, a generalized eigenvalue problem is formulated through a similar BE technique. The accuracy and reliability of the results is assessed by FEM solutions employing solid or shell modelling. Both open- and closed-shaped cross section bars are examined and the necessity to include nonuniform torsional and STSD effects in the dynamic analysis of bars is demonstrated.

  7. Optical fiber accelerometer based on MEMS torsional micromirror

    Science.gov (United States)

    Zeng, Fanlin; Zhong, Shaolong; Xu, Jing; Wu, Yaming

    2008-03-01

    A novel structure of optical fiber accelerometer based on MEMS torsional micro-mirror is introduced, including MEMS torsional micro-mirror and optical signal detection. The micro-mirror is a non-symmetric one, which means that the torsional bar supporting the micro-mirror is not located in the axis where the center of the micro-mirror locates. The optical signal detection is composed of PIN diode and dual fiber collimator, which is very sensitive to the coupling angle between the input fiber and output fiber. The detection principle is that acceleration is first transformed into torsional angle of the micro-mirror, then, optical insertion loss of the dual fiber collimator caused by the angle can be received by PIN. So under the flow of acceleration to torsional angle to optical signal attenuation to optical power detection, the acceleration is detected. The theory about sensing and optical signal detect of the device are discussed in this paper. The sensitive structure parameters and performance parameters are calculated by MATLAB. To simulate the static and modal analysis, the finite element analysis, ANSYS, is employed. Based on the above calculation, several optimization methods and the final structure parameters are given. The micro-mirror is completed by using silicon-glass bonding and deep reactive ion etching (DRIE). In the experiment, the acceleration is simulated by electrostatic force and the test results show that the static acceleration detection agrees with the theory analysis very well.

  8. Higher Franz-Reidemeister torsion

    CERN Document Server

    Igusa, Kiyoshi

    2002-01-01

    The book is devoted to the theory of topological higher Franz-Reidemeister torsion in K-theory. The author defines the higher Franz-Reidemeister torsion based on Volodin's K-theory and Borel's regulator map. He describes its properties and generalizations and studies the relation between the higher Franz-Reidemeister torsion and other torsions used in K-theory: Whitehead torsion and Ray-Singer torsion. He also presents methods of computing higher Franz-Reidemeister torsion, illustrates them with numerous examples, and describes various applications of higher Franz-Reidemeister torsion, particularly for the study of homology of mapping class groups. Packed with up-to-date information, the book provides a unique research and reference tool for specialists working in algebraic topology and K-theory.

  9. Torsional Elastic Property Measurements of Selected Orthodontic Archwires.

    Science.gov (United States)

    1987-01-01

    Triple-Stranded Stainless Steel Wires - Evaluation of Mechanical Properties and Comparison with Titanium Alloy Alternatives. Angle Orthod 57:18-32...Greenberg AR: Effects of Composition and Cross-section on the Elastic Properties of Orthodontic Archwires. Angle Orthod 51:325-341, 1981. S11. Thurow, RC... Orthod 71:565-573, 1977. 14. Wagner JA, Nikolai RJ: Stiffness of Incisor Segments of Edgewise Arches in Torsion and Bending. Angle Orthod 55:37-50, 1985

  10. Clinical measurement of compensatory torsional eye movement during head tilt.

    Science.gov (United States)

    Lim, Han Woong; Kim, Ji Hong; Park, Seung Hun; Oh, Sei Yeul

    2017-03-01

    To measure the degree of compensatory torsional eye movement during head tilt using a fundus photography method. We enrolled 55 healthy subjects who were 20-66 years of age. Fundus photographs were obtained in the presumed baseline position and in stepwise head tilt positions to evaluate ocular torsion using a non-mydriatic fundus camera. Horizontal marks on the nose were photographed simultaneously to evaluate head tilt. Images were analysed using Photoshop to measure the degree of ocular torsion and head tilt. A consistent compensatory torsional eye movement was observed in all subjects during head tilt. The degree of compensatory torsional eye movement showed a positive correlation with the angle of head tilt. Ocular torsional disconjugacy was observed during head tilt, with larger excycloductional eye movement than incycloductional eye movement (4.88 ± 2.91° versus 4.50 ± 2.76°, p eye movement was significantly associated with the degree of head tilt (β = 0.191, p eye movement. Considering the availability of fundus photography in clinical ophthalmology practice, the proposed method can be used as a clinical tool to measure compensatory torsional eye movement. © 2016 Acta Ophthalmologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.

  11. Isolated Fallopian Tube Torsion

    Directory of Open Access Journals (Sweden)

    S. Kardakis

    2013-01-01

    Full Text Available Isolated torsion of the Fallopian tube is a rare gynecological cause of acute lower abdominal pain, and diagnosis is difficult. There are no pathognomonic symptoms; clinical, imaging, or laboratory findings. A preoperative ultrasound showing tubular adnexal masses of heterogeneous echogenicity with cystic component is often present. Diagnosis can rarely be made before operation, and laparoscopy is necessary to establish the diagnosis. Unfortunately, surgery often is performed too late for tube conservation. Isolated Fallopian tube torsion should be suspected in case of acute pelvic pain, and prompt intervention is necessary.

  12. Multiscale modeling and simulation of nanotube-based torsional oscillators

    Directory of Open Access Journals (Sweden)

    Xiao Shaoping

    2006-01-01

    Full Text Available AbstractIn this paper, we propose the first numerical study of nanotube-based torsional oscillators via developing a new multiscale model. The edge-to-edge technique was employed in this multiscale method to couple the molecular model, i.e., nanotubes, and the continuum model, i.e., the metal paddle. Without losing accuracy, the metal paddle was treated as the rigid body in the continuum model. Torsional oscillators containing (10,0 nanotubes were mainly studied. We considered various initial angles of twist to depict linear/nonlinear characteristics of torsional oscillators. Furthermore, effects of vacancy defects and temperature on mechanisms of nanotube-based torsional oscillators were discussed.

  13. Triorchidism with Torsion

    African Journals Online (AJOL)

    are retractile and more mobility is at increased risk for torsion. An increased prevalence of carcinoma has also been reported.[1]. Case Report. A 72-year-old man presented with vague pain in the lower abdomen and scrotum. There was no history of trauma and he stated that the pain was severe in nature and had been ...

  14. Tumour, Torsion or Trauma?

    African Journals Online (AJOL)

    finally revealed testicular torsion. Remarkably, the testis was viable and the finding of a hematoma of the epididymis suggested a history of trauma which was not forthcoming from the patient. The acute scrotum demands expeditious attention and the clinician must aim to reach a definitive diagnosis in the shortest time ...

  15. Triorchidism with Torsion

    African Journals Online (AJOL)

    scrotal mass. Of the remaining cases, 20% of the testes are inguinal and 5% are retroperitoneal.[1,2] Supernumerary testes are retractile and more mobility is at increased risk for torsion. An increased prevalence of carcinoma has also been reported.[1]. Case Report. A 72-year-old man presented with vague pain in the ...

  16. Tibiotalar torsion: bioengineering paradigm.

    Science.gov (United States)

    Michele, A A; Nielsen, P M

    1976-10-01

    1. Medial tibiotalar torsion is the most common disorder peculiar to mankind. 2. The pathogonomic findings are (a) an axial medially rotated and adducted distal third of the shaft of the tibia, (b) the plafond of the tibia with its mortise containing the "track-bound" talus, which is deflected strongly toward the tibial side, (c) an exaggerated midtarsal equinus, (d) ostensible restriction of dorsiflexion of the hindfoot against the tibia, (e) mild separation of the distal tibiofibular articulation, and (f) forward displacement of the gravitational axis to the naviculocunei-form joint. 3. Faulty leg crossing in utero resulting in an abnormal pelvofemoral-tibial design is discussed and its important consequences in the vulnerable 40 per cent of the population are emphasized. 4. The kinesiomechanics of the leg, ankle and foot is reviewed. 5. The radiographic parameters of medial tibiotalar torsion are presented, as well as the multiple facets of the clinical examination. 6. Methods of treatment depending on age and severity of the disorder are recommended. Surgery, detortional casts, and corrective footwear are discussed. Shoes presently available are inadequate for tibiotalar torsion and therefore engineering principles must be applied in the design and construction of all footwear, including sneakers and sportswear. This can be done only if the pathological biomechanics of this group of disorders is recognized. Biplane proximal tibial osteotomy is recommended in refractory cases, especially when tibiotalar torsion is demonstrated. 7. After 30 years of experience, the author finds that results with these patients have been uniformly good to excellent, depending on age and mode of treatment. 8. In medial tibiotalar torsion, the consequent adaptive changes are readily observed, but rarely are they recognized as the inevitable sequelae of medial tibiotalar torsion. 9. Adaptive compensating disorders are identified and their mechanism described. 10. The management of

  17. Computed tomographic determination of tibial torsion in the dog.

    Science.gov (United States)

    Aper, Rhonda; Kowaleski, Michael P; Apelt, Detlef; Drost, W Tod; Dyce, Jonathan

    2005-01-01

    The goal of this study was to develop a method for computed tomographic (CT) measurement of tibial torsion, and to compare this technique with direct anatomic measurement of tibial torsion in cadaveric canine tibiae. Paired hind limbs of 10 cadaveric dogs were mounted on a custom-designed limb holding apparatus. One-millimeter thick, contiguous, transverse CT slices were obtained from the distal femur to the proximal tibia and 2 mm CT slices were obtained from the distal tibia to the proximal tarsus. The tibiae were freed of soft tissues and digital photographic images of the proximal and distal articular surfaces were obtained with the camera lens aligned perpendicular to the long axis of the tibia. Multiple proximal and distal tibial axes were identified on the images; two proximal and two distal axes were found to be repeatable in all specimens in both the direct and CT methods. The torsion angle was calculated by determining the difference between the axis angles for each pair of proximal and distal axes. There was no significant difference in torsion angle identified between the direct photographic and CT method for any pair of proximal and distal axes. CT determination of tibial torsion is a rapid and accurate method, and warrants investigation in clinical patients.

  18. Management of adnexal torsion

    Directory of Open Access Journals (Sweden)

    Neslihan Erkal

    2014-03-01

    Full Text Available Objective: To evaluate clinical findings, operative reports, the pathological results of patients with diagnosis of adnexal torsion. Methods: Fourteen patients with diagnosis of adnexal torsion who presented to our clinic between January 2009 and March 2013 were included in this retrospective analysis. Data including clinical findings, operative reports, the pathological results were recorded. Results: The mean age of the patients was 28.1 ± 10.5 with a range of 16 to 52 years. All patients underwent ultrasonography, and a pelvic mass appearance was detected in all cases. The mean diameter of the mass was 8,04±2,96 cm. All of the patients had lower abdominal pain, nausea and vomiting. Six patients were operated laparoscopically, while eight patients had laparotomy. Detorsion and cystectomy was performed in 7 (50.0% of the patients. Two of patients were pregnant in operation time that treated by cystectomy and detorsion of the ovaries successfully in the first and third trimester (one by laparoscopy. There was one patient of isolated fallopian tube torsion due to hydrosalpinks treated by laparoscopic salpingectomy. Two of the patients had paratubal cyst and tubal torsion. Detorsion and cystectomy by laparoscopy and salpingectomy by laparotomy were performed for these patients respectively. The most common histopathology was serous cystadenoma (28,6%. Conclusion: Adnexal torsion is a rare gynecologic emergency of women and occur in reproductive ages mostly. Prompt diagnosis and conservative treatment is important for the safety of ovaries and fallopian tubes and future fertility. J Clin Exp Invest 2014; 5 (1: 7-11

  19. Assessment of Left Ventricular Torsion in Short Axis View between Healthy Subjects and Significant Coronary Artery Disease Patients

    Directory of Open Access Journals (Sweden)

    Zahra Arab

    2013-09-01

    Full Text Available Background: Coronary artery disease causes changes in biomechanical parameters and function of myocardial. Recently, torsion angle is one of the most important mechanical parameters. Therefore in this study, torsion angle in healthy subjects and LAD significant coronary artery disease patients, using echo tracking method in short axis view, was evaluated.Materials and Methods: In cross sectional study, 14 healthy subjects and 10 patients with significant stenosis of LAD were evaluated. Two dimensional echocardiography images were scanned in apical and basal parasternal short axis view were recorded. Successive ultrasonic images were processed by echo tracking under block matching algorithm and peak torsion angle were estimated. Difference between healthy group and patient group were extracted by using peak torsion angle by the confidence level of 95%.Results: In this study, basal rotation angle, apical rotation angle and torsion angle in short axis view in significant coronary artery disease patients significantly decreased 33%, 44% and 38% relative to healthy subjects, respectively. Also time to reach peak torsion angle in LAD coronary artery stenosis patients increased 19% relative to healthy group.Conclusion: It seems, torsion angle in short axis view, can diagnose LAD coronary artery stenosis patients reative to healthy subject.

  20. Inferior oblique weakening surgery on ocular torsion in congenital superior oblique palsy

    Directory of Open Access Journals (Sweden)

    Jinho Lee

    2015-06-01

    Full Text Available AIM:To investigate changes in fundus excyclotorsion after inferior oblique myectomy or myotomy.METHODS:The records of 21 patients undergoing strabismus surgery by a single surgeon between 2009 and 2012 were examined. Only patients who had undergone an inferior oblique myectomy or myotomy, with or without horizontal rectus muscle surgery, were evaluated. Digital fundus photographs were obtained, and the angle formed by a horizontal line passing through the optic disc center and a reference line connecting the foveola and optic disc center was measured. Associated clinical factors examined include age at the time of surgery, presence or absence of a head tilt, degree of preoperative vertical deviation, torsional angle, inferior oblique muscle overaction/superior oblique muscle underaction, and surgery laterality. Whether the procedure was performed alone or in combination with a horizontal rectus muscle surgery was also examined.RESULTS:Mean preoperative torsional angle was 12.0±6.4°, which decreased to 6.9±5.7° after surgery (P<0.001, paired t-test. Torsional angle also decreased from 15.1±7.0° to 6.2±4.3° in the myectomy group (P<0.001, paired t-test but there were no significant changes in the myotomy group (P=0.093, Wilcoxon signed rank test. Multivariable linear regression analysis showed that preoperative torsional angle, degree of inferior oblique overaction, and age at surgery independently and significantly affected postoperative torsional angle.CONCLUSION:Mean torsional angle decreased after inferior oblique myectomy. Degree of preoperative torsional angle, inferior oblique overaction, and age at surgery influence postoperative torsional angle.

  1. Nonlinear Hysteretic Torsional Waves.

    Science.gov (United States)

    Cabaret, J; Béquin, P; Theocharis, G; Andreev, V; Gusev, V E; Tournat, V

    2015-07-31

    We theoretically study and experimentally report the propagation of nonlinear hysteretic torsional pulses in a vertical granular chain made of cm-scale, self-hanged magnetic beads. As predicted by contact mechanics, the torsional coupling between two beads is found to be nonlinear hysteretic. This results in a nonlinear pulse distortion essentially different from the distortion predicted by classical nonlinearities and in a complex dynamic response depending on the history of the wave particle angular velocity. Both are consistent with the predictions of purely hysteretic nonlinear elasticity and the Preisach-Mayergoyz hysteresis model, providing the opportunity to study the phenomenon of nonlinear dynamic hysteresis in the absence of other types of material nonlinearities. The proposed configuration reveals a plethora of interesting phenomena including giant amplitude-dependent attenuation, short-term memory, as well as dispersive properties. Thus, it could find interesting applications in nonlinear wave control devices such as strong amplitude-dependent filters.

  2. Femtosecond torsional relaxation

    Science.gov (United States)

    Clark, J.; Nelson, T.; Tretiak, S.; Cirmi, G.; Lanzani, G.

    2012-03-01

    Molecular conformational reorganization following photon absorption is a fundamental process driving reactions such as the cis-trans isomerization at the heart of the primary step of vision and can be exploited for switching in artificial systems using photochromics. In general, conformational change occurs on a timescale defined by the energy of the main vibrational mode and the rate of energy dissipation. Typically, for a conformational change such as a twist around the backbone of a conjugated molecule, this occurs on the tens of picoseconds timescale. However, here we demonstrate experimentally that in certain circumstances the molecule, in this case an oligofluorene, can change conformation over two orders of magnitude faster (that is sub-100fs) in a manner analogous to inertial solvent reorganization demonstrated in the 1990s. Theoretical simulations demonstrate that non-adiabatic transitions during internal conversion can efficiently convert electronic potential energy into torsional kinetic energy, providing the `kick' that prompts sub-100fs torsional reorganization.

  3. Effects of torsion on the thermal conductivity of multi-layer graphene

    Science.gov (United States)

    Si, Chao; Lu, Gui; Cao, Bing-Yang; Wang, Xiao-Dong; Fan, Zhen; Feng, Zhi-Hai

    2017-05-01

    This work employs the equilibrium molecular dynamics method to study the effects of torsion on the thermal conductivity of multi-layer graphene. Thermal conductivities of twisted 10-layer 433.91 × 99.68 Å2 graphene with torsion angles of 0°, 11.25°, 22.5°, 33.75°, 45°, 67.5°, 90°, 112.5°, and 135° are calculated. The corresponding radial distribution functions and nearest atomic distances are calculated to reveal the effects of torsion on lattice structures. The spectral energy density (SED) method is utilized to analyze the phonon transport properties. It is very interesting that the thermal conductivity of multi-layer graphene decreases slightly at first and then increases with the increasing torsion angle, and the valley is located at θG = 22.5° with the lowest thermal conductivity of 4692.40 W m-1 K-1. The torsion effect can be considered as a combination of the compression effect and the dislocation effect. Further SED analysis confirms that the effect of dislocation on thermal conductivities can be negligible, while the compression effect decreases the phonon lifetimes of flexural out-of-plane acoustic (ZA) branches and increases the ZA group velocities and the phonon specific heat. The decrease becomes dominated when the torsion angle is small, whereas the increase becomes more and more dominated when the torsion angle becomes larger, which are responsible for the reported variation of thermal conductivities.

  4. Torsional Rigidity of Minimal Submanifolds

    DEFF Research Database (Denmark)

    Markvorsen, Steen; Palmer, Vicente

    2006-01-01

    We prove explicit upper bounds for the torsional rigidity of extrinsic domains of minimal submanifolds $P^m$ in ambient Riemannian manifolds $N^n$ with a pole $p$. The upper bounds are given in terms of the torsional rigidities of corresponding Schwarz symmetrizations of the domains in warped...... for the torsional rigidity are actually attained and give conditions under which the geometric average of the stochastic mean exit time for Brownian motion at infinity is finite....

  5. Stability in quadratic torsion theories

    Science.gov (United States)

    Vasilev, Teodor Borislavov; Cembranos, Jose A. R.; Valcarcel, Jorge Gigante; Martín-Moruno, Prado

    2017-11-01

    We revisit the definition and some of the characteristics of quadratic theories of gravity with torsion. We start from a Lagrangian density quadratic in the curvature and torsion tensors. By assuming that General Relativity should be recovered when the torsion vanishes and investigating the behaviour of the vector and pseudo-vector torsion fields in the weak-gravity regime, we present a set of necessary conditions for the stability of these theories. Moreover, we explicitly obtain the gravitational field equations using the Palatini variational principle with the metricity condition implemented via a Lagrange multiplier.

  6. Torsional behavior of chiral single-walled and double-walled carbon nanotubes

    Science.gov (United States)

    Dian-Rong, Han; Lei, Zhu; Ya-Fei, Dai; Cheng-Lin, Luo

    2017-10-01

    The torsional behavior of the chiral single-walled carbon nanotubes (SWCNTs) and double-walled carbon nanotubes (DWCNTs) is investigated using molecular dynamics (MD) method. The results show that the torsional behavior of chiral DWCNTs presents a weaker direction dependent than that of SWCNTs. The critical buckling shear strain of DWCNT in the untwisting direction of the outer tube is always greater than that in the opposite direction. The torsional rigidities of the DWCNT and its outer tubes are approximately identical. However, torsional elastic range of the DWCNT is much higher than that of the outer tube. Moreover, the torsional direction dependency of incommensurate chiral (n 1  +  m 1, -m1)@ (n 2,m 2) tube is weaker than that of commensurate (n 1,m 1)@ (n 2,m 2) tube, which implies that if the chiral angles of the inner and the outer tube of a DWCNT are arranged in opposite directions, the torsional direction dependency of a DWCNT will be further reduced. Meanwhile, rotational inertia of the DWCNT remains nearly unchanged under torsion in a quite large torsional range. These conclusions will be helpful in designing torsional components of NEMS (nano-electromechanical system) using carbon tubes.

  7. A STUDY ON TIBIAL TORSION IN ADULT DRY TIBIA OF EAST AND SOUTH INDIAN POPULATION

    Directory of Open Access Journals (Sweden)

    Jami Sagar Prusti

    2017-05-01

    Full Text Available BACKGROUND Rotational deformities of the lower limbs are very common. There is increasing evidence that abnormal torsion in the tibia is associated with severe knee and ankle arthritis. Primary knee osteoarthritis is a leading cause of disability in older persons. Varus or valgus alignment increases the risk of osteoarthritis. Coexistence of tibial torsional deformity may increase the risk further. Variability in the tibial torsion has been reported and is due to the torsional forces applied on tibia during development. The aim of the study is to estimate the angle of tibial torsion on both sides and both sexes. The present study was an attempt to provide baseline data of tibial torsion in the East and South Indian population. MATERIALS AND METHODS The study was conducted mechanically on 100 dry adult unpaired human tibia, i.e. 50 male and 50 female bones. The measurements were recorded and statistically analysed using Student’s unpaired t-test using GraphPad Prism 5.0 (free trial version. RESULTS Out of the 100 tibia undertaken, mean value of tibial torsion angle obtained is 25.8°. In males, it is 23.68° and in females it is about 27.86°. Statistical analysis revealed significant greater average angle of tibial torsion in female bones. The angle of the right-sided bones was more and this was statistically significant. CONCLUSION The gender variation for the angle could be the result of the difference in lifestyle in day-to-day activities. The knowledge of the angle in a population could be helpful in understanding the incidence of pathogenesis related to gait and knee osteoarthritis and in view of reconstructive surgeries in orthopaedic practice.

  8. Molecular dynamics study of effects of nickel coating on torsional behavior of single-walled carbon nanotube

    Energy Technology Data Exchange (ETDEWEB)

    Song Haiyang, E-mail: gsfshy@sohu.co [School of Science, Xi' an University of Posts and Telecommunications, Xi' an 710121 (China); Zha Xinwei [School of Science, Xi' an University of Posts and Telecommunications, Xi' an 710121 (China)

    2011-02-15

    The effects of nickel coating on the torsional behaviors of single-walled carbon nanotubes (SWCNTs) subject to torsion motion are investigated using the molecular dynamics (MD) simulation method. The simulation results show that regardless of chirality, defect or radius, nickel coating can considerably enhance the critical torque of SWCNTs. However, by comparing the critical torsion angle between nickel-coated SWCNTs and corresponding pristine SWCNTs, it is found that nickel coating in small-radius nanotubes does induce a reduction in the critical torsion angle. The results also show that the structural failure of nickel coated imperfect (9,0) SWCNT occurs at an obviously higher critical torque in comparison with uncoated (9,0) SWCNT with a vacancy defect. Furthermore, we also find that the critical torque of a short nickel coated SWCNT is bigger than that of a long one, while the critical torsion angle for a short tube is smaller than that for a long one.

  9. Testicular torsion: A surgical emergency

    Energy Technology Data Exchange (ETDEWEB)

    Prater, J.M.; Overdorf, B.S. (Surgical Residency Program at Yale University, New Haven, CT (USA))

    1991-09-01

    Testicular torsion is caused by twisting of the spermatic cord, which results in compromised testicular blood flow. The degree of ischemic injury is determined by the severity of arterial compression and the interval between the onset of symptoms and surgical intervention. Torsion usually occurs at puberty, and an anatomic defect known as bell-clapper deformity is usually present. Typical symptoms include acute scrotal pain with associated nausea and vomiting. Up to one-half of patients report previous similar episodes. On examination, the testis is high-riding, tender, swollen and firm. Testicular scan or Doppler ultrasound examination can be helpful in distinguishing torsion from acute epididymitis. Prompt surgical treatment is indicated to reduce the torsion, and bilateral orchiopexy is performed to prevent recurrence. Exocrine function, as determined by semen analysis, is often abnormal after unilateral torsion. 25 references.

  10. Torsion testing of bed joints

    DEFF Research Database (Denmark)

    Hansen, Klavs Feilberg; Pedersen, Carsten Mørk

    2008-01-01

    This paper describes a simple test method for determining the torsion strength of a single bed joint between two bricks and presents results from testing using this test method. The setup for the torsion test is well defined, require minimal preparation of the test specimen and the test can...... be carried out directly in a normal testing machine. The torsion strength is believed to be the most important parameter in out-of-plane resistance of masonry walls subjected to bending about an axis perpendicular to the bed joints. The paper also contains a few test results from bending of small walls about...... an axis perpendicular to the bed joints, which indicate the close connection between these results and results from torsion tests. These characteristics make the torsion strength well suited to act as substitute parameter for the bending strength of masonry about an axis perpendicular to the bed joints....

  11. Spin and torsion in gravitation

    CERN Document Server

    De Sabbata, Venzo

    1994-01-01

    This book gives an exposition of both the old and new results of spin and torsion effects on gravitational interactions with implications for particle physics, cosmology etc. Physical aspects are stressed and measurable effects in relation to other areas of physics are discussed.Among the topics discussed are: alternative ways of unifying gravity with electroweak and strong interactions by an energy dependent spin torsion coupling constant; the idea that all interactions can be understood as originating from spin curvature coupling; the possibility of cosmological models with torsion providing

  12. Hematosalpinx torsion in an adolescent

    Directory of Open Access Journals (Sweden)

    Inês Vaz

    2016-02-01

    Full Text Available Introduction: Isolated fallopian tube torsion is an uncommon cause of acute lower abdominal pain. Ectopic pregnancy, hydro or hematosalpinx, endometriosis, adnexal masses and other causes of adnexal disease are predisposing factors. The diagnosis is difficult and often delayed due to the lack of pathognomonic symptoms, characteristic physical signs, and specific imaging and laboratory studies. Defi nitive diagnosis requires a surgical approach. Case report: The authors present a case of hematosalpinx and its tubal torsion in a virgin teenager with no prior predisposing factors. Discussion: This rare case may highlight a new insight into pathophysiology of tubal torsion and recalls hematosalpinx as a differential diagnosis.

  13. Postoperative Change in Ocular Torsion in Intermittent Exotropia: Relationship with Postoperative Surgical Outcomes.

    Directory of Open Access Journals (Sweden)

    Ju-Yeun Lee

    Full Text Available The aim of this study was to determine whether objective ocular torsion in intermittent exotropia (IXT changes after recession surgery, and to evaluate the relationship between change in ocular torsion and clinical parameters in IXT. Sixty patients between 3 and 14 years of age underwent lateral rectus (LR recession for IXT. Digital fundus photographs were obtained from both eyes of each subject and the disc-foveal angle (ocular torsion was calculated using image software. We compared the preoperative and postoperative amount of ocular torsion, and analyzed the correlation between the difference in ocular torsion (DOC and clinical parameters including age, duration of strabismus, stereoacuity, amount of preoperative exodeviation, and mean dose response. We categorized the patients according to DOC value: positive DOC value as group 1, and negative DOC value as group 2. A correlation between ocular torsion dominance and fixation preference was also investigated using the Kappa test. The mean ocular torsion was 15.8 ± 4.6 degrees preoperatively and 13.7 ± 5.1 degrees postoperatively. Compared with preoperative values, the mean ocular torsion showed a significant decrease after LR recession (p<0.001, and a greater preoperative ocular torsion was significantly associated with the amount of DOC (r = 0.37, p<0.001. Degree of stereopsis, mean dose-response, and postoperative exodeviation were significantly different between group 1 (positive DOC and group 2 (negative DOC (p<0.001, 0.030, and 0.001 respectively. The Kappa test showed that there was a significant correlation between the dominance of ocular torsion and fixation preference (p = 0.020. Therefore, change in ocular torsion after LR recession can be a useful supplementary indicator for evaluating the degree of fusional control and for predicting postoperative surgical response in IXT.

  14. Computational and experimental study of probability of galloping and torsional divergence at span structure

    Directory of Open Access Journals (Sweden)

    Fedosova Anastasia

    2017-01-01

    Full Text Available The paper considers study of aeroeslatic stability of span structure using computational and experimental modelling of aerodynamics by wind-tunnel tests and numerical simulation at software package ANSYS CFX. Wind-tunnel test were conducted to to determine steady state wind load coefficients for zero wind attack angle. Using numerical simulation aerodynamic coefficients were obtained for different wind attack angles from −5 to 5 degree with verification to experimental data at zero wind attack angle. Using this approach of combination the accuracy of experimental studies and the convenience of numerical simulation the problems of forecasting phenomena such as galloping and torsion torsional divergence at span structures were solved.

  15. Optimum Shapes and Sizes on Torsion Behaviour of I-Beam with Web Opening

    Directory of Open Access Journals (Sweden)

    De’nan F.

    2016-01-01

    Full Text Available Numerical study on torsion behaviour of I-beam with web opening was carried out and presented in this paper. Optimum shapes and sizes which enhance the torsion behaviour of the I-beam with web opening as well as lead to economic design in terms of both manufacture and usage.Comparison is made between I-beam without web opening and I-beam with various shapes and sizes of web opening. Different types of finite elements model, sizes and types of web opening were used to investigate the effect of various shapes and sizes of web opening on the torsion behaviour. The results are expressed in terms of torsional rotation. It is concluded that I-beam without web opening has lower torsional resistance compared to that of I-beam with various shapes of web opening. Meanwhile, the model 2 is the optimum model compare to model 1.The size of opening has slightly effect on the torsional angles values. It was noted that the optimum web opening size is 0.5D due to the low values of the torsional angle values compared with 0.6D and 0.7D.

  16. Radiographic and computed tomographic determination of femoral varus and torsion in the dog.

    Science.gov (United States)

    Dudley, Robert M; Kowaleski, Michael P; Drost, Wm Tod; Dyce, Jonathan

    2006-01-01

    Diagnosis and quantification of femoral varus and femoral torsion using radiographs is technically challenging due to the difficulty in determining proper positioning. The purpose of this study is to describe a computed tomographic technique for determination of femoral varus and femoral torsion and to compare this technique, and standard radiography, to anatomic preparation, for the measurement of femoral varus and femoral torsion in normal dogs. Nine canine cadavers, visually and radiographically free of orthopedic disease of the hip and stifle joints, were utilized for analysis. Femoral varus was determined using a craniocaudal radiograph, a craniocaudal radiograph obtained after confirming accurate positioning using horizontal beam fluoroscopy, and computed tomography (CT). Femoral torsion (expressed as angle of version) was determined using an axial radiographic projection obtained from distal to proximal and CT. Each femur was dissected free of soft tissues, and direct determination of femoral varus and femoral torsion was performed using digital photographic images. All radiologic and photographic images were digitally measured to quantify the magnitude of femoral varus and femoral torsion. For femoral varus, no difference (P = 0.149) between the three different imaging techniques and the anatomic preparation was identified. For femoral torsion, no difference (P = 0.059) between the two imaging techniques and the anatomic preparation was identified. Well positioned radiographs and the described computed tomographic method are both as accurate as anatomic preparation for the measurement of both femoral varus and femoral torsion in normal dogs.

  17. Constraining spacetime torsion with LAGEOS

    Science.gov (United States)

    March, Riccardo; Bellettini, Giovanni; Tauraso, Roberto; Dell'Agnello, Simone

    2011-11-01

    We compute the corrections to the orbital Lense-Thirring effect (or frame-dragging) in the presence of spacetime torsion. We analyze the motion of a test body in the gravitational field of a rotating axisymmetric massive body, using the parametrized framework of Mao, Tegmark, Guth and Cabi. In the cases of autoparallel and extremal trajectories, we derive the specific approximate expression of the corresponding system of ordinary differential equations, which are then solved with methods of Celestial Mechanics. We calculate the secular variations of the longitudes of the node and of the pericenter. We also show how the LAser GEOdynamics Satellites (LAGEOS) can be used to constrain torsion parameters. We report the experimental constraints obtained using both the nodes and perigee measurements of the orbital Lense-Thirring effect. This makes LAGEOS and Gravity Probe B complementary frame-dragging and torsion experiments, since they constrain three different combinations of torsion parameters.

  18. Existence of Torsional Solitons in a Beam Model of Suspension Bridge

    Science.gov (United States)

    Benci, Vieri; Fortunato, Donato; Gazzola, Filippo

    2017-11-01

    This paper studies the existence of solitons, namely stable solitary waves, in an idealized suspension bridge. The bridge is modeled as an unbounded degenerate plate, that is, a central beam with cross sections, and displays two degrees of freedom: the vertical displacement of the beam and the torsional angles of the cross sections. Under fairly general assumptions, we prove the existence of solitons. Under the additional assumption of large tension in the sustaining cables, we prove that these solitons have a nontrivial torsional component. This appears relevant for security since several suspension bridges collapsed due to torsional oscillations.

  19. Harmonic structures and intrinsic torsion

    DEFF Research Database (Denmark)

    Conti, Diego; Madsen, Thomas Bruun

    We discuss the construction of 8-manifolds with harmonic Sp(2)Sp(1)-structures. In particular, we find 10 new examples of nilmanifolds that admit a closed 4-form Omega whose stabiliser is Sp(2)Sp(1). Our constructions entail the notion of SO(4)-structures on 7-manifolds. We present a thorough inv...... investigation of the intrinsic torsion of such structures; in addition to the construction of harmonic structures, this analysis leads to explicit Lie group examples with invariant intrinsic torsion....

  20. Harmonic structures and intrinsic torsion

    DEFF Research Database (Denmark)

    Conti, Diego; Madsen, Thomas Bruun

    2015-01-01

    We discuss the construction of Sp(2)Sp(1)-structures whose fundamental form is closed. In particular, we find 10 new examples of 8-dimensional nilmanifolds that admit an invariant closed 4-form with stabiliser Sp(2) Sp(1). Our constructions entail the notion of SO(4)-structures on 7-manifolds. We...... present a thorough investigation of the intrinsic torsion of such structures, leading to the construction of explicit Lie group examples with invariant intrinsic torsion....

  1. Thin-Walled Beam Theories and Their Applications in the Torsional Strength Analysis of Ship Hulls.

    Science.gov (United States)

    1987-01-01

    numerous deep web frames and transverse bulkheads. The system has been utilized in a study of a frigate under an assumed torsional/flexural load, the...transverse bulkheads and r deep web frames. Figure 18 indicates that, despite the poor agreement in twist angle, the axial stress results compare quite...under torsional loads. This will be the case for a typical warship hull, because of the large number of deep web frames and transverse bulkheads. The

  2. Effect of Torsional and Fatigue Preloading on HyFlex EDM Files.

    Science.gov (United States)

    Shen, Ya; Tra, Charles; Hieawy, Ahmed; Wang, Zhejun; Haapasalo, Markus

    2018-01-12

    The purpose of this study was to evaluate the effect of a low amount of torsional preloading on the fatigue life and different degrees of cyclic fatigue on torsional failure of HyFlex EDM (EDM; Coltene-Whaledent, Allstetten, Switzerland) and HyFlex CM (CM; Coltene-Whaledent) instruments. EDM and CM files were used. The fatigue resistance was examined in a 5-mm radius and 60° single curve, and the mean number of cycles to failure (Nf) was recorded. The torque and rotation angles at failure of the instruments were measured according to ISO 3630-1. New files were precycled to 0%, 50%, and 75% of the Nf, and torsional tests were then performed. Other new files were preloaded at 5%, 15%, 25%, and 50% of the mean rotation angles before the fatigue test. The fracture surfaces of the fragments were examined under a scanning electron microscope. The fatigue resistance of EDM instruments was higher than that of CM instruments (P < .05). The torque and angle of rotation at fracture of the files were similar. Torsional preloading lowered the Nf of EDM at 15% preloading (P < .05) and the Nf of CM at 50% preloading (P < .05). However, the Nf of EDM files even with 50% torsional preloading was significantly higher than unused CM files (P < .05). Fatigue prestressing even at 75% had no negative effect on the torque and rotation angle of the EDM files. Moderate precycling (50%) of EDM files increased their torsional resistance. The fractographic patterns corresponded to the pattern defined by the last stage test. A low amount (15%) of torsional preloading reduced the fatigue resistance of EDM files, whereas even extensive (75%) precyclic fatigue was not detrimental to their torsional resistance. Copyright © 2017 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  3. Can Ocular Torsion be Measured Using the Slitlamp Biomicroscope?

    Directory of Open Access Journals (Sweden)

    Kothari Mihir

    2005-03-01

    Full Text Available PURPOSE: To evaluate and compare a stereo-biomicroscopic technique of ocular torsion measurement with fundus photographic technique. METHODS: This prospective masked observational study included 72 eyes of 36 consecutive subjects with normal ocular motility. The disc-foveal angle was measured by two masked investigators using a slitlamp stereo-biomicroscopic and fundus photographic technique. RESULTS: The mean age was 13.7 years (6 - 44 years, and 15 (41.6% were males. The average torsion using the slitlamp technique was 5.5 3.3o and 6.1 4.3o with fundus photographic technique. Clinical agreement between the two techniques for 5o and 6o torsion was 81% and 90% respectively. The average difference between the two techniques was 3.0 2.6o. The mean inter-ocular difference was 3.3 2.7o (SD, 2.77 and 5.5 4.6o using the slitlamp and fundus photographic technique respectively. The Pearson correlation coefficient (r2 was 0.5 CONCLUSION: The fundus photographic technique remains the gold standard test for the measurement of ocular torsion. The slitlamp biomicroscopic method can be useful where a fundus camera is unavailable. Further studies are required to test the repeatability of these tests.

  4. Painless Ovarian Torsion Mimicking a Uterine Myoma

    Directory of Open Access Journals (Sweden)

    Cheng-Kuo Lin

    2006-12-01

    Conclusion: Ovarian torsion is a significant cause of acute lower abdominal pain in women and is a gynecologic surgical emergency. Nevertheless, surgical strategies are usually impeded because of ambiguous warning signs. Clinicians may be misled by certain conditions such as silent ovarian torsion. Although there may be no specific indication, the diagnosis of ovarian torsion should be considered on finding a pelvic mass.

  5. Influence of cyclic torsional preloading on cyclic fatigue resistance of nickel - titanium instruments.

    Science.gov (United States)

    Pedullà, E; Lo Savio, F; Boninelli, S; Plotino, G; Grande, N M; Rapisarda, E; La Rosa, G

    2015-11-01

    To evaluate the effect of different torsional preloads on cyclic fatigue resistance of endodontic rotary instruments constructed from conventional nickel-titanium (NiTi), M-Wire or CM-Wire. Eighty new size 25, 0.06 taper Mtwo instruments (Sweden & Martina), size 25, 0.06 taper HyFlex CM (Coltene/Whaledent, Inc) and X2 ProTaper Next (Dentsply Maillefer) were used. The Torque and distortion angles at failure of new instruments (n = 10) were measured, and 0% (n = 10), 25%, 50% and 75% (n = 20) of the mean ultimate torsional strength as preloading condition were applied according to ISO 3630-1 for each brand. The twenty files tested for every extent of preload were subjected to 20 or 40 torsional cycles (n = 10). After torsional preloading, the number of cycles to failure was evaluated in a simulated canal with 60° angle of curvature and 5 mm of radius of curvature. Data were analysed using two-way analysis of variance. The fracture surface of each fragment was examined with a scanning electron microscope (SEM). Data were analysed by two-way analyses of variance. Preload repetitions did not influence the cyclic fatigue of the three brands; however, the 25%, 50% and 75% torsional preloading significantly reduced the fatigue resistance of all instruments tested (P HyFlex CM preloaded with 25% of the maximum torsional strength (P > 0.05). Torsional preloads reduced the cyclic fatigue resistance of conventional and treated (M-wire and CM-wire) NiTi rotary instruments except for size 25, 0.06 taper HyFlex CM instruments with a 25% of torsional preloading. © 2014 International Endodontic Journal. Published by John Wiley & Sons Ltd.

  6. Pancreatic torsion in a dog

    OpenAIRE

    Brabson, Tamera L.; Maki, Lynn C.; Newell, Susan M.; Ralphs, S. Christopher

    2015-01-01

    A 6-month-old male intact Cane Corso mastiff dog was presented for a recent history of vomiting, abdominal pain, and lethargy. A diagnosis of pancreatic torsion was made during abdominal exploratory surgery and was confirmed with histopathology. The dog underwent partial pancreatectomy and recovered with no complications.

  7. [Testicular torsion: A case report].

    Science.gov (United States)

    García-Fernández, Gustavo; Bravo-Hernández, Alberto; Bautista-Cruz, Raúl

    The acute scrotum is an emergency. Testicular torsion represents approximately 25% of the causes. The annual incidence of testicular torsion is approximately 1/4,000 persons under 25 years, with highest prevalence between 12 and 18 years old. It usually occurs without apparent cause, but it has been associated with anatomical, traumatic, and environmental factors, among others. A male 15 year-old male, with no history of importance, was seen in the Emergency Department, presenting with a sudden and continuous pain in the left testicle. It was accompanied by a pain that radiated to the abdomen and left inguinal area, with nausea and vomiting of more than 12h onset. Doppler ultrasound showed changes suggestive of testicular torsion. Surgery was performed that showed findings of a necrotic left testicle with rotation of the spermatic cord of 360°. A left orchiectomy was performed. Testicular torsion should always be considered one of the leading causes of acute scrotal pain. Delays in diagnosis should be avoided as this is directly related to the percentage of testicular salvage or loss. Copyright © 2016 Academia Mexicana de Cirugía A.C. Publicado por Masson Doyma México S.A. All rights reserved.

  8. Torsion and Open Book Decompositions

    OpenAIRE

    Etnyre, John B.; Vela-Vick, David Shea

    2009-01-01

    We show that if (B,\\pi) is an open book decomposition of a contact 3-manifold (Y,\\xi), then the complement of the binding B has no Giroux torsion. We also prove the sutured Heegaard-Floer c-bar invariant of the binding of an open book is non-zero.

  9. Torsion of a wandering spleen

    African Journals Online (AJOL)

    splenic ligaments, particularly the gastrosplenic and splenorenal ligaments. Wandering spleen may present in varying forms, from an incidentally detected radiological mass to an asymptomatic, mobile intra-abdominal mass or, as in our case, the more sinister presentation of severe pain secondary to torsion. Case report.

  10. Left ventricular remodeling and torsion dynamics in hypertensive patients.

    Science.gov (United States)

    Cameli, Matteo; Lisi, Matteo; Righini, Francesca Maria; Massoni, Alberto; Mondillo, Sergio

    2013-01-01

    Left ventricular (LV) torsion is a fundamental component of wall motion and plays an important role to optimize ventricular ejection fraction. The aim of our study was to calculate by speckle tracking echocardiography LV twist angle in patients with hypertension and LV remodeling, analyzing torsional indices in all patterns of hypertrophy, in comparison to torsional dynamics of age-matched healthy subjects. Hypertensive patients (n = 202) were divided in three groups, patients with concentric remodeling (n = 70), concentric hypertrophy (n = 68) and eccentric hypertrophy (n = 64), in relation to the echocardiographic measurements of relative wall thickness and LV mass, analyzing their torsional patterns by speckle tracking in comparison to age-matched control group. Compared to healthy controls, LV twist angle was increased in patients with hypertension and concentric remodeling (15.2° ± 1.9° vs. 11.0° ± 1.6°; p < 0.001), reaching the highest value in patients with concentric hypertrophy (19.4° ± 2.6°); instead LV twist angle presented depressed in the group of patients that presented eccentric hypertrophy (5.0° ± 1.1°). Regarding LV untwisting rate, it was higher in the concentric remodeling and concentric hypertrophy groups (-123.1°/s ± 12.1°/s and -145.1°/s ± 15.5°/s, respectively) in comparison with the controls (-90.0°/s ± 10.1°/s; p < 0.0001 for both). Instead, lower values of LV untwisting rate were observed in the eccentric remodeling group (-81.6°/s ± 8.1°/s), not significantly different to controls' values (p = 0.09). Enhanced LV twist angle appears to be a compensatory mechanism in hypertensive patients during the earlier stages of concentric remodeling and concentric hypertrophy; this hyper-torsion is inevitably loss in the more advanced stage of eccentric hypertrophy.

  11. MR evaluation of femoral neck version and tibial torsion

    Energy Technology Data Exchange (ETDEWEB)

    Koenig, James Karl; Dwek, Jerry R. [University of California, San Diego, Children' s Hospital and Health Center, Department of Radiology, San Diego, CA (United States); Pring, Maya E. [Rady Children' s Hospital, Department of Pediatric Orthopedic Surgery, San Diego, CA (United States)

    2012-01-15

    Abnormalities of femoral neck version have been associated with a number of hip abnormalities in children, including slipped capital femoral epiphysis, proximal femoral focal deficiency, coxa vara, a deep acetabulum and, rarely, developmental dysplasia of the hip. Orthopedic surgeons also are interested in quantifying the femoral neck anteversion or retroversion in children especially to plan derotational osteotomies. Historically, the angle of femoral version and tibial torsion has been measured with the use of radiography and later by CT. Both methods carry with them the risks associated with ionizing radiation. Techniques that utilize MR are used less often because of the associated lengthy imaging times. This article describes a technique using MRI to determine femoral neck version and tibial torsion with total scan times of approximately 10 min. (orig.)

  12. Symmetry of chiral nanotubes: Natural torsion and diffraction evidence

    Energy Technology Data Exchange (ETDEWEB)

    Vukovic, Tatjana; Lazic, Natasa; Milosevic, Ivanka; Damnjanovic, Milan [NanoLab, Faculty of Physics, University of Belgrade, Studentski trg 12, Belgrade 11001 (Serbia)

    2012-12-15

    Optimizations performed with geometrical, molecular mechanics, and density functional models show that chiral carbon nanotube configuration is slightly twisted with respect to the rolled-up geometry. The torsion angle is small, <1 Aa{sup -1} for ultrathin tubes, and decreases with tube diameter. The effect can be explained through breaking of local symmetry of the equally distant neighbors in graphene, which is diminished by the torsion. Although, the twist is small, still, we single out features in diffraction patterns which can distinguish between twisted and non-twisted configurations, at least for narrow single-walled carbon nanotubes. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  13. Effects of torsional degree of freedom, geometric nonlinearity, and gravity on aeroelastic behavior of large-scale horizontal axis wind turbine blades under varying wind speed conditions

    DEFF Research Database (Denmark)

    Jeong, Min-Soo; Cha, Myung-Chan; Kim, Sang-Woo

    2014-01-01

    . In this study, a numerical analysis considering blade torsional degree of freedom, geometric nonlinearity, and gravity was utilized to examine the effects of these factors on the aeroelastic blade behavior of a large-scale horizontal axis wind turbine. The results predicted that flapwise deflection is mainly...... affected by the torsional degree of freedom, which causes the blade bending deflections to couple to torsional deformation, thereby varying the aerodynamic loads through changes in the effective angle of attack. Edgewise deflection and torsional deformation are mostly influenced by the periodic...

  14. TORSION OF THE VERMIFORM APPENDIX: A CASE REPORT

    Directory of Open Access Journals (Sweden)

    Dr. Imtiaz Wani

    2009-07-01

    Full Text Available Torsion of the vermiform appendix is a rare condition with few cases reported in the literature. Various factors predispose to torsion. Various factors predispose to torsion. We report a case of primary torsion of the vermiform appendix. The clinical presentation was indistinguishable from acute appendicitis and the diagnosis was made at operation. Appendix was preileal in position and the direction of torsion was anticlockwise. There was intrinsic torsion with no obvious factor for torsion identified. Appendectomy was performed.

  15. Influence of mistuning on blade torsional flutter

    Science.gov (United States)

    Srinivasan, A. V.

    1980-01-01

    An analytical technique for the prediction of fan blade flutter was evaluated by utilizing first stage fan flutter data from tests on an advanced high performance engine. The formulation includes both aerodynamic and mechanical coupling among all the blades of the assembly. Mistuning is accounted for in the analysis so that individual blade inertias, frequencies, or damping can be considered. Airfoil stability was predicted by calculating a flutter determinant, the eigenvalues of which indicate the extent of susceptibility to flutter. When blade to blade differences in frequencies are considered, a stable system is predicted for the test points examined. For a tuned system, it was found that torsional flutter can be predicted at a limited number of interblade phase angles. Examination of these phase angles indicated that they were "close" to the condition of acoustic resonance. For the range of Mach numbers and reduced frequencies considered, the so called subcritical flutter cannot be predicted. The essential influence of mechanical coupling among the blades is to change the frequencies of the system with little or no change in damping; however, aerodynamic coupling together with mechanical coupling could change not only frequencies, but also damping in the system, with a trend toward instability.

  16. Semiclassics of rotation and torsion.

    OpenAIRE

    Braun, Petr A.; Gerwinski, Peter; Haake, Fritz; Schomerus, Henning

    1996-01-01

    We discuss semiclassical approximations of the spectrum of the periodically kicked top, both by diagonalizing the semiclassically approximated Floquet matrix F and by employing periodic-orbit theory. In the regular case when F accounts only for a linear rotation periodic-orbit theory yields the exact spectrum. In the chaotic case the first method yields the quasienergies with an accuracy of better than 3% of the mean spacing. By working in the representation where the torsional part of the Fl...

  17. Investigations on Torsion of the Two-Chords Single Laced Members

    Science.gov (United States)

    Lorkowski, Paweł; Gosowski, Bronisław

    2017-06-01

    The paper presents experimental and numerical studies to determine the equivalent second moment of area of the uniform torsion of the two-chord steel single laced members. The members are used as poles of railway traction network gates, and steel columns of framed buildings as well. The stiffness of uniform torsion of this kind of columns allows to the determine the critical loads of the spatial stability. The experimental studies have been realized on a single - span members with rotation arrested at their ends, loaded by a torque applied at the mid-span. The relationship between angle of rotation of the considered cross-section and the torque has been determined. Appropriate numerical model was created in the ABAQUS program, based on the finite element method. A very good compatibility has been observed between experimental and numerical studies. The equivalent second moment of area of the uniform torsion for analysed members has been determined by comparing the experimental and analytical results to those obtained from differential equation of non-uniform torsion, based on Vlasov's theory. Additionally, the parametric analyses of similar members subjected to the uniform torsion, for the richer range of cross-sections have been carried out by the means of SOFiSTiK program. The purpose of the latter was determining parametrical formulas for calculation of the second moment of area of uniform torsion.

  18. In Situ SEM Torsion Test of Metallic Glass Microwires Based on Micro Robotic Manipulation

    Directory of Open Access Journals (Sweden)

    Chenchen Jiang

    2017-01-01

    Full Text Available Microwires, such as metallic, semiconductor, and polymer microwires and carbon fibers, have stimulated great interest due to their importance in various structural and functional applications. Particularly, metallic glass (MG microwires, because of their amorphous atoms arrangement, have some unique mechanical properties compared with traditional metals. Despite the fact that substantial research efforts have been made on the mechanical characterizations of metallic glass microwires under tension or flexural bending, the mechanical properties of microwires under torsional loading have not been well studied, mainly due to the experimental difficulties, such as the detection of torsion angle, quantitative measurement of the torsional load, and the alignment between the specimen and torque meter. In this work, we implemented the in situ SEM torsion tests of individual La50Al30Ni20 metallic glass (MG microwires successfully based on a self-developed micro robotic mechanical testing system. Unprecedented details, such as the revolving vein-pattern along the torsion direction on MG microwires fracture surface, were revealed. Our platform could provide critical insights into understanding the deformation mechanisms of other microwires under torsional loading and can even be further used for robotic micromanufacturing.

  19. Newton-Cartan gravity and torsion

    Science.gov (United States)

    Bergshoeff, Eric; Chatzistavrakidis, Athanasios; Romano, Luca; Rosseel, Jan

    2017-10-01

    We compare the gauging of the Bargmann algebra, for the case of arbitrary torsion, with the result that one obtains from a null-reduction of General Relativity. Whereas the two procedures lead to the same result for Newton-Cartan geometry with arbitrary torsion, the null-reduction of the Einstein equations necessarily leads to Newton-Cartan gravity with zero torsion. We show, for three space-time dimensions, how Newton-Cartan gravity with arbitrary torsion can be obtained by starting from a Schrödinger field theory with dynamical exponent z = 2 for a complex compensating scalar and next coupling this field theory to a z = 2 Schrödinger geometry with arbitrary torsion. The latter theory can be obtained from either a gauging of the Schrödinger algebra, for arbitrary torsion, or from a null-reduction of conformal gravity.

  20. Re-torsion of the ovaries

    DEFF Research Database (Denmark)

    Hyttel, Trine E W; Bak, Geske S; Larsen, Solveig B

    2015-01-01

    The increasing use of de-torsion of the ovaries may result in re-torsion. This review addresses risk of re-torsion and describes preventive strategies to avoid re-torsion in pre-menarcheal girls, and fertile and pregnant women. We clinically reviewed PubMed, Embase, Trip and Cochrane databases....... The main outcome measures were re-torsion and viability of ovary with fixation measures. A total of 38 publications including 71 girls, 363 fertile women, and 69 pregnant women were found to be relevant. All studies were case reports or case series, sometimes with non-randomized controls. The studies show...... considerable heterogeneity in design, population, management and outcome. Only four studies included more than 50 cases. In pregnancy the risk of re-torsion was as high as 19.5-37.5%; among fertile women it was 28.6%. Most articles concluded that fixation of the ovaries to the pelvic sidewall or plication...

  1. Dirac operators and Killing spinors with torsion; Dirac-Operatoren und Killing-Spinoren mit Torsion

    Energy Technology Data Exchange (ETDEWEB)

    Becker-Bender, Julia

    2012-12-17

    On a Riemannian spin manifold with parallel skew torsion, we use the twistor operator to obtain an eigenvalue estimate for the Dirac operator with torsion. We consider the equality case in dimensions four and six. In odd dimensions we describe Sasaki manifolds on which equality in the estimate is realized by Killing spinors with torsion. In dimension five we characterize all Killing spinors with torsion and obtain certain naturally reductive spaces as exceptional cases.

  2. Femoral Torsion: Impact of Femur Position on CT and Stereoradiography Measurements.

    Science.gov (United States)

    Morvan, Gérard; Guerini, Henri; Carré, Grégory; Vuillemin, Valérie

    2017-08-01

    The purpose of this study is to evaluate stereoradiographic measurements of femoral torsion with different femoral positions, in comparison with CT measurements, with use of the current standard axial-slice technique. We hypothesize that CT measurements vary with femoral spatial positioning because of the resulting projection onto the CT plane, whereas stereoradiographic measurements, which are derived from a 3D reconstruction of the femur, remain constant. Both in vitro and in vivo studies were conducted. CT and stereoradiographic examinations were performed using 30 dry femurs in the following six femoral positions: neutral position (with the femoral mechanical axis aligned with the longitudinal axis of the CT scanner or stereoradiography system), 10° of abduction, 10° of adduction, 5° of flexion, 10° of flexion, and 5° of extension. The impact of femoral position on torsion measurement was assessed using paired t tests. In addition, 18 patients (mean [± SD] age, 42.3 ± 19.9 years) who underwent both CT and stereoradiography examinations were retrospectively assessed. The correlation between femoral positioning and torsion measurement was determined using the Pearson correlation coefficient. Flexion and extension statistically significantly affected CT measurement of femoral torsion (p 0.21). A strong correlation existed between hip flexion and the difference between femoral torsion measured by CT and stereoradiography (r = -0.80). The accuracy of femoral torsion determined by axial CT depends on the position of the femur. Hip flexion significantly reduced the femoral torsion angle measured by CT. Conversely, the accuracy of stereoradiography was independent of femur positioning. Thus, stereoradiography is preferable to CT for accurate measurement of femoral torsion, while it also substantially reduces the radiation dose.

  3. Intranatal Torsion of Polydactyly: A Rare Event.

    Science.gov (United States)

    Gupta, Priyanka; Neogi, Sujoy; Shukla, Amlin; Patwari, A K

    2016-01-01

    Polydactyly is one of the most common anomalies of hand and/or foot. Postnatal torsion of pedunculated polydactyly is a well known complication but intranatal torsion has been infrequently described in published literature. Here, we describe a case of pedunculated ulnar polydactyly which was gangrenous at birth due to intranatal torsion. Controversies surrounding the management of narrow pedicled pedunculated polydactyly by traditional method of suture ligation at base are also discussed.

  4. Microstructural white matter changes in primary torsion dystonia.

    Science.gov (United States)

    Carbon, Maren; Kingsley, Peter B; Tang, Chengke; Bressman, Susan; Eidelberg, David

    2008-01-30

    Primary torsion dystonia (PTD) has been conceptualized as a disorder of the basal ganglia. However, recent data suggest a widespread pathology involving motor control pathways. In this report, we explored whether PTD is associated with abnormal anatomical connectivity within motor control pathways. We used diffusion tensor magnetic resonance imaging (DT-MRI) to assess the microstructure of white matter. We found that fractional anisotropy, a measure of axonal integrity and coherence, was significantly reduced in PTD patients in the pontine brainstem in the vicinity of the left superior cerebellar peduncle and bilaterally in the white matter of the sensorimotor region. Our data thus support the possibility of a disturbance in cerebello-thalamo-cortical pathways as a cause of the clinical manifestations of PTD. 2007 Movement Disorder Society

  5. Torsional Buckling and Writhing Dynamics of Elastic Cables and DNA

    Energy Technology Data Exchange (ETDEWEB)

    Goyal, S; Perkins, N C; Lee, C L

    2003-02-14

    Marine cables under low tension and torsion on the sea floor can undergo a dynamic buckling process during which torsional strain energy is converted to bending strain energy. The resulting three-dimensional cable geometries can be highly contorted and include loops and tangles. Similar geometries are known to exist for supercoiled DNA and these also arise from the conversion of torsional strain energy to bending strain energy or, kinematically, a conversion of twist to writhe. A dynamic form of Kirchhoff rod theory is presented herein that captures these nonlinear dynamic processes. The resulting theory is discretized using the generalized-method for finite differencing in both space and time. The important kinematics of cross-section rotation are described using an incremental rotation ''vector'' as opposed to traditional Euler angles or Euler parameters. Numerical solutions are presented for an example system of a cable subjected to increasing twist at one end. The solutions show the dynamic evolution of the cable from an initially straight element, through a buckled element in the approximate form of a helix, and through the dynamic collapse of this helix through a looped form.

  6. The odd side of torsion geometry

    DEFF Research Database (Denmark)

    Conti, Diego; Madsen, Thomas Bruun

    2014-01-01

    We introduce and study a notion of `Sasaki with torsion structure' (ST) as an odd-dimensional analogue of Kähler with torsion geometry (KT). These are normal almost contact metric manifolds that admit a unique compatible connection with 3-form torsion. Any odd-dimensional compact Lie group is shown......, we relate the ST structure to a KT structure on the space of leaves, and show that both the cylinder and the cone over an ST manifold are KT, although only the cylinder behaves well with respect to closedness of the torsion form. Finally, we introduce a notion of `G-moment map'. We provide criteria...

  7. Experimental and numerical research on forging with torsion

    Science.gov (United States)

    Petrov, Mikhail A.; Subich, Vadim N.; Petrov, Pavel A.

    2017-10-01

    Increasing the efficiency of the technological operations of blank production is closely related to the computer-aided technologies (CAx). On the one hand, the practical result represents reality exactly. On the other hand, the development procedure of new process development demands unrestricted resources, which are limited on the SMEs. The tools of CAx were successfully applied for development of new process of forging with torsion and result analysis as well. It was shown, that the theoretical calculations find the confirmation both in praxis and during numerical simulation. The mostly used constructional materials were under study. The torque angles were stated. The simulated results were evaluated by experimental procedure.

  8. Effect of bilateral superior oblique split lengthening on torsion

    Directory of Open Access Journals (Sweden)

    Jitendra Jethani

    2015-01-01

    Full Text Available Introduction: Superior oblique split lengthening (SOSL is done for weakening of superior oblique. It corrects the superior oblique overaction (SOOA and A pattern. Its effect on the torsion of the eye is not known. We present our data on the effect of this particular procedure on torsion. Materials and Methods: We did a study of 16 patients (32 eyes who underwent bilateral SOSL and compared the disc foveal angle (DFA preoperatively and postoperatively. The split lengthening was done from 4 mm to 7 mm depending upon the overaction of superior oblique. Results: The mean age was 15.3 ± 8.4 years. Mean preoperative DFA in the right eye (RE was −3.9° and in the left eye (LE was −2.9°. Mean postoperative DFA in RE was 0.2° and in LE was 0.9°. The mean change in the DFA for RE was 4.1° ± 1.3° and for LE was 3.8° ± 1.2°. All the patients were aligned horizontally within 6 prism diopter and no pattern and no diplopia postoperatively. The A pattern was corrected in all the patient postsurgery. For each mm of surgery, an improvement of 0.8° was seen in the DFA. Conclusion: We report the effect of SOSL on torsion. The SOSL reduces intorsion postsurgery and is, therefore, a valuable procedure in SOOA where both pattern and in torsion needs to be corrected.

  9. Electrothermally-Actuated Micromirrors with Bimorph Actuators—Bending-Type and Torsion-Type

    Directory of Open Access Journals (Sweden)

    Cheng-Hua Tsai

    2015-06-01

    Full Text Available Three different electrothermally-actuated MEMS micromirrors with Cr/Au-Si bimorph actuators are proposed. The devices are fabricated with the SOIMUMPs process developed by MEMSCAP, Inc. (Durham, NC, USA. A silicon-on-insulator MEMS process has been employed for the fabrication of these micromirrors. Electrothermal actuation has achieved a large angular movement in the micromirrors. Application of an external electric current 0.04 A to the bending-type, restricted-torsion-type, and free-torsion-type mirrors achieved rotation angles of 1.69°, 3.28°, and 3.64°, respectively.

  10. Simultaneous acute appendicitis with right testicular torsion

    Directory of Open Access Journals (Sweden)

    Tanveer Akhtar

    2012-01-01

    Full Text Available We present a child with both acute appendicitis and torsion of the right testis presenting at the same time. Testicular torsion possibly occurring due to vomiting in acute appendicitis so far has not been reported in the literature.

  11. Torsional vibrations of infinite composite poroelastic cylinders

    African Journals Online (AJOL)

    user

    Abstract. A study of torsional vibrations of an infinite composite poroelastic circular solid cylinder made of two different materials is made. The frequency equation of such torsional vibrations is obtained following analytical model based on Biot's theory of wave propagation in liquid saturated porous media. Each dilatation of ...

  12. EXPERIMENTAL AND ANALYTICAL COMPARISON OF TORSION ...

    African Journals Online (AJOL)

    This study investigated the effect of combined actions of torsional moments, bending moments and shear forces in reinforced concrete beams with concrete compressive strength of 30N/mm2.The ultimate torsional moments, bending moments, and shear forces of the beams were determined experimentally, through a simple ...

  13. Misdiagnosed Adult Testicular Torsion: Case Report | Ndaguatha ...

    African Journals Online (AJOL)

    Adult testicular torsion is thought to be rare if not relatively unusual. The rarity could be an underestimation since there are many episodes of missed torsions and misdiagnosis with other conditions of acute scrotum despite the now widespread ultra sound availability that are being reported in the literature. Such a ...

  14. Teenage testicular torsion. | Onuigbo | International Journal of ...

    African Journals Online (AJOL)

    Aim: To study testicular torsion in teenagers in the Igbo community. Method: A retrospective study was carried out as regards requests for pathological examination of specimens received at a Regional Reference Laboratory based in Enugu. Results: Over a period of 30 years, 28 surgical specimens of testicular torsion in ...

  15. Appendicular Torsion | Dubhashi | Nigerian Journal of Surgery

    African Journals Online (AJOL)

    . It can be primary or secondary. This is a case report of 52-year-old female with 180° anti-clockwise rotation of the appendix. Torsion can further leads to strangulation and infarction of the organ. Appendicular torsion could be included in the ...

  16. Right paratesticular abscess mimicking neonatal testicular torsion ...

    African Journals Online (AJOL)

    U.O. Ezomike

    Abstract. The clinical presentation of neonatal paratesticular abscess may closely resemble that of, neonatal testicular torsion and the use of scrotal ultrasonography to differentiate the two has low, sensitivity. We propose early operative treatment of suspected neonatal testicular torsion to salvage, the testicle in cases of ...

  17. TESTICULAR TORSION: CASE REPORT R. T. KUREMU ...

    African Journals Online (AJOL)

    hi-tech

    2004-05-05

    May 5, 2004 ... Possible precipitating factors in testicular torsion include cold, exercise, sexual fore play, abnormal position during sleep or sitting, sudden closing of thighs, trauma, tight pants, coughing and defection(2). Early diagnosis remains a clinical challenge. Even though the clinical features of torsion are typical, the.

  18. Torsional strain of TaS3 whiskers on the charge-density wave depinning.

    Science.gov (United States)

    Pokrovskii, V Ya; Zybtsev, S G; Gorlova, I G

    2007-05-18

    We find that an electric current I exceeding the threshold value results in torsional strain of o-TaS3 samples with one contact freely suspended. The rotation angle deltavarphi of the free end achieves several degrees and exhibits hysteresis as a function of I. The sign of deltavarphi depends on the I polarity; a polar axis along the conducting chains (the c axis) is pointed out. We associate the effect with surface shear of the charge-density wave (CDW) coupled to the crystal shear. The current-induced torsional strain could be treated in terms of enormous piezoelectric coefficients (>10(-4) cm/V) corresponding to shear. In essence, TaS3 appears to be a ready torsional actuator based on the unique intrinsic property of the CDW.

  19. Cyclic Axial-Torsional Deformation Behavior of a Cobalt-Base Superalloy

    Science.gov (United States)

    Bonacuse, Peter J.; Kalluri, Sreeramesh

    1995-01-01

    The cyclic, high-temperature deformation behavior of a wrought cobalt-base super-alloy, Haynes 188, is investigated under combined axial and torsional loads. This is accomplished through the examination of hysteresis loops generated from a biaxial fatigue test program. A high-temperature axial, torsional, and combined axial-torsional fatigue database has been generated on Haynes 188 at 760 C. Cyclic loading tests have been conducted on uniform gage section tubular specimens in a servohydraulic axial-torsional test rig. Test control and data acquisition were accomplished with a minicomputer. The fatigue behavior of Haynes 188 at 760 C under axial, torsional, and combined axial-torsional loads and the monotonic and cyclic deformation behaviors under axial and torsional loads have been previously reported. In this paper, the cyclic hardening characteristics and typical hysteresis loops in the axial stress versus axial strain, shear stress ,versus engineering shear strain, axial strain versus engineering shear strain. and axial stress versus shear stress spaces are presented for cyclic in-phase and out-of-phase axial-torsional tests. For in-phase tests, three different values of the proportionality constant lambda (the ratio of engineering shear strain amplitude to axial strain amplitude, are examined, viz. 0.86, 1.73, and 3.46. In the out-of-phase tests, three different values of the phase angle, phi (between the axial and engineering shear strain waveforms), are studied, viz., 30, 60, and 90 degrees with lambda equals 1.73. The cyclic hardening behaviors of all the tests conducted on Haynes 188 at 760 C are evaluated using the von Mises equivalent stress-strain and the maximum shear stress-maximum engineering shear strain (Tresca) curves. Comparisons are also made between the hardening behaviors of cyclic axial, torsional, and combined in-phase (lambda = 1.73 and phi = 0) and out-of-phase (lambda = 1.73 and phi = 90') axial-torsional fatigue tests. These comparisons

  20. Thermoelastic damping in torsion microresonators with coupling effect between torsion and bending

    Science.gov (United States)

    Tai, Yongpeng; Li, Pu; Fang, Yuming

    2014-02-01

    Predicting thermoelastic damping (TED) is crucial in the design of high Q MEMS resonators. In the past, there have been few works on analytical modeling of thermoelastic damping in torsion microresonators. This could be related to the assumption of pure torsional mode for the supporting beams in the torsion devices. The pure torsional modes of rectangular supporting beams involve no local volume change, and therefore, they do not suffer any thermoelastic loss. However, the coupled motion of torsion and bending usually exists in the torsion microresonator when it is not excited by pure torque. The bending component of the coupled motion causes flexural vibrations of supporting beams which may result in significant thermoelastic damping for the microresonator. This paper presents an analytical model for thermoelastic damping in torsion microresonators with the coupling effect between torsion and bending. The theory derives a dynamic model for torsion microresonators considering the coupling effect, and approximates the thermoelastic damping by assuming the energy loss to occur only in supporting beams of flexural vibrations. The thermoelastic damping obtained by the present model is compared to the measured internal friction of single paddle oscillators. It is found that thermoelastic damping contributes significantly to internal friction for the case of the higher modes at room temperature. The present model is validated by comparing its results with the finite-element method (FEM) solutions. The effects of structural dimensions and other parameters on thermoelastic damping are investigated for the representative case of torsion microresonators.

  1. Surgical management of persistent intoeing gait due to increased internal tibial torsion in children.

    Science.gov (United States)

    Davids, Jon R; Davis, Roy B; Jameson, Lisa C; Westberry, David E; Hardin, James W

    2014-06-01

    Intoeing gait is frequently seen in developing children, and in most cases it resolves with growth. However, persistent, extreme intoeing gait, due to increased internal tibial torsion, may disrupt gait function. At our institution, children with symptomatic intoeing gait are evaluated per a standardized protocol, which includes quantitative gait analysis. When the primary cause is increased internal tibial torsion, surgical correction by supramalleolar tibial rotational osteotomy is recommended. The study design was a retrospective case series, with normative controls (31 children), of typically developing children with symptomatic intoeing gait who were treated by isolated supramalleolar tibial rotation osteotomy (28 children, with 45 treated extremities). Preoperative and 1-year postoperative physical examination, kinematic, kinetic, and pedobarographic data were compared. Patient-reported and parent-reported outcomes in functional and satisfaction domains were assessed by items on a 7-point questionnaire. Internal tibial torsion, foot progression angle, and knee rotation were normalized following tibial rotation osteotomy. Compensatory external hip rotation and external knee progression angle were significantly improved but not normalized following tibial rotation osteotomy. An increased coronal plane knee varus moment was significantly decreased following surgery. Increased sagittal and transverse plane knee moments were significantly decreased but not normalized following surgery. Significant improvements were observed with respect to tripping, falling, foot/ankle pain, and knee pain following surgery. Children with symptomatic intoeing gait because of increased internal tibial torsion have characteristic primary and compensatory kinematic gait deviations that result in increased loading about the knee during the stance phase of gait. Correction of the internal tibial torsion by rotation osteotomy improves, but does not normalize, all the kinematic and

  2. The availability of radiological measurement of tibial torsion: three-dimensional computed tomography reconstruction.

    Science.gov (United States)

    Shin, Sang-Yeop; Yoon, Chul Ho; Lee, Eun Shin; Oh, Min-Kyun; Kim, A Ram; Park, Jong Moon; Shin, Jun-Hwa; Shin, Hee Suk

    2011-10-01

    To assess the intra-rater and inter-rater reliability for measuring tibial torsion measurements by a radiographic method using three-dimensional computed tomography reconstruction (3D-CT) and to compare the physical measures to those of 3D-CT. The study included 33 children who presented with intoeing gait. Tibial torsion was measured by 3D-CT. Distal reference point was the bimalleolar axis. Proximal reference points were the transtibial axis and posterior condylar axis. Physical measurements included thigh-foot angle (TFA) and bimalleolar angle (BMA). 3D-CT measurement and physical measurement were performed twice at both lower extremities by each rater. The intra-rater and inter-rater reliability were calculated by intraclass correlation coefficiency (ICC). The relationship between radiological and physical examination was calculated by Spearman correlation coefficient. The 3D-CT measures for tibial torsion were reliable within individual raters and between different raters. However, physical measures for tibial torsion were reliable within an individual rater but not reliable between raters. The 3D-CT measures by any proximal reference axis were more reliable within a rater and between raters than physical measurements. There was no significant impact introduced by the selection of the proximal reference axis. The correlation coefficiency between 3D-CT and physical measurement methods was low. Because the 3D-CT measurements for tibial torsion are more reliable than physical measurements, we recommend that accurate diagnosis of internal tibial torsion should be detected by using 3D-CT measurements. Also, considering the disadvantages of radiological measurements, physical measurement may be used for short term follow-up by same raters, as intra-rater reliability is relatively good.

  3. Radiography, computed tomography and virtual bronchoscopy in four dogs and two cats with lung lobe torsion.

    Science.gov (United States)

    Schultz, R M; Peters, J; Zwingenberger, A

    2009-07-01

    This report describes the imaging features of radiography, computed tomography and virtual bronchoscopy in dogs and cats with lung lobe torsions. The medical records, thoracic radiographs and computed tomography images of four dogs and two cats with confirmed lung lobe torsions were retrospectively reviewed. Computed tomography with virtual bronchoscopy showed bronchial narrowing, collapse or occlusion in all six animals, while this was only appreciated on one radiographic examination. A tapering terminating angle of the air-filled bronchus proximal or distal to the collapsed region was seen only on computed tomography and virtual bronchoscopy in all six animals. The vesicular emphysema pattern typical of lung lobe torsion was seen on three computed tomographies but only on one radiographic examination. The lung lobe torsion-specific findings of vesicular emphysema and a proximally narrowed or occluded bronchus were more easily recognised on computed tomography and virtual bronchoscopy than with radiographs. Computed tomography slices acquired through the bronchus and lung lobe of interest in a cat or dog with possible lung lobe torsion can be reformatted into virtual bronchoscopic images that can be utilised along with computed tomography to help make a more definitive preoperative diagnosis.

  4. Improvement of torsional resistance from bond strength and reinforcement indexes in fibrous normal strength concrete beams

    Science.gov (United States)

    Karim, F. R.; Abu Bakar, B. H.; Kok Keong, Choong; Aziz, O. Q.

    2017-10-01

    This paper highlights the effect of tension stiffening index on the torsional resistance at the crack and peak loads in under-reinforced fibrous normal strength concrete beams under pure torsional loading. The different grades of steel reinforcements were used with different surface texture of the reinforcements. Four fibrous normal strength concrete beams were cast and tested under pure torsional loading. The beams were designed based on ACI 318, where the clear span to depth ratio and aspect ratio of the section were kept constant at 5.72 and 1.22, respectively. The test results verified that the torsional resistance of peak load was improved up to 12.91% due to the reduction of tension stiffening index, whereas the cracking torsional resistance and the value of twisting angle were slightly influenced. Moreover, due to the reduction of tension stiffening index up to 11.66%, the strain in transverse and longitudinal reinforcements were enhanced up to 91.8% and 73.6%, respectively.

  5. Acute and intermittent testicular torsion: Analysis of presentation ...

    African Journals Online (AJOL)

    Background: Testicular torsion compromises the blood supply to the testes and may result in testicular loss or damage if not dealt with promptly. It can occur either as acute testicular torsion (ATT) or intermittent testicular torsion (ITT). This study examines the presentation, management, and outcome of adult testicular torsion.

  6. Torsion of the vermiform appendix: A case report | Wani | Internet ...

    African Journals Online (AJOL)

    Torsion of the vermiform appendix is a rare condition with few cases reported in the literature. Various factors predispose to torsion. Various factors predispose to torsion. We report a case of primary torsion of the vermiform appendix. The clinical presentation was indistinguishable from acute appendicitis and the diagnosis ...

  7. Ultrasonographic diagnosis of adnexal torsion in pregnancy

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Eun Ju; Kim, Jai Keun [Ajou University School of Medicine, Suwon (Korea, Republic of)

    2002-06-15

    To evaluate the usefulness of ultrasonography (US) and color Doppler sonography (CDS) in the diagnosis of adnexal torsion in pregnancy.US and CDS findings of 31 patients with surgically proven adnexal torsion during pregnancy were retrospectively reviewed. On US, the presence of twisted vascular pedicle (TVP), ovary, or adnexal mass were evaluate while te presence of blood flow within the TVP and ovary or adnexal mass were evaluated on CDS. Adnexal torsion was diagnosed by the detection of TVP and absent flow to the ovary, and the diagnostic accuracy of US was assessed. TVP was detectable on US in 25 of 31 cases (80.7%) with adnexal torsion during pregnancy. In four cases, torsion of the ovary was seen as the multiple peripherally located in the enlarged ovary, and in one case, torsion of the hyperstimulated ovary appeared as multiple cysts measuring between 2 to 7 cm in diameter combined with swollen parenchyma. Ovarian mass was detected on the same side of the torsion in 27 cases, the diameter ranging from 3.5 to 22 cm (mean=8.4 cm); 15 of them were mostly cystic while nine masses with the mixture of cystic and solid portions and two masses consisted of solid portion were also observed on US. The blood flow was present in the twisted vessels on CDS in 13 of 25 cases with TVP, and flow within the ovary or an adnexal mass was seen in 12 cases. The remaining 12 cases showed no flow within TVP and the ovary. In six cases with no visible TVP, the blood flow of the ovary was present in five cases and absent in one case. Torsion was confidently diagnosed in 25 cases with the visible TVP and in one case with absent ovarian flow on US and CDS, showing the diagnostic accuracy of 83.9%. US and CDS can be useful diagnostic modalities in the diagnosis of adnexal torsion in pregnancy.

  8. Left-sided omental torsion: CT appearance

    Energy Technology Data Exchange (ETDEWEB)

    Aoun, N.; Haddad-Zebouni, S.; Slaba, S.; Ghossain, M. [Hotel-Dieu de France Hospital, Beirut (Lebanon). Dept. of Radiology; Noun, R. [Hotel-Dieu de France Hospital, Beirut (Lebanon). Dept. of General Surgery

    2001-01-01

    A 34-year-old male presented with exquisite left flank pain. Computed tomography showed a hyperdense vascular structure surrounded by whirling linear streaks situated in the greater omentum under the splenic flexure of the colon. Omental stranding extended caudally into the pelvis where part of the inflamed omentum entered a left inguinal hernia sac. Surgery revealed left-sided torsion of the greater omentum. Left-sided omental torsion is infrequent and pre-operative diagnosis is rarely established. The CT findings of an omental fatty mass with a whirling pattern is characteristic of omental torsion. Preoperative diagnosis is important because conservative management has been suggested. (orig.)

  9. Femoral Shaft Torsion in Injured and Uninjured Ballet Dancers and Its Association with Other Hip Measures: A Cross-sectional Study.

    Science.gov (United States)

    Hafiz, Eliza; Hiller, Claire E; Nicholson, Leslie L; Nightingale, Elizabeth J; Grimaldi, Alison; Refshauge, Kathryn M

    2016-03-01

    Low range femoral torsion, termed "lateral shaft torsion," has been associated with greater range of hip external rotation and turnout in dancers. It is also hypothesized that achieving greater turnout at the hip minimizes torsion at the knee, shank, ankle, and foot, and consequently reduces incidence of lower limb injuries. The primary aims of this study were to investigate: 1. differences in range of femoral shaft torsion between dancers with and without lower limb injuries; and 2. the relationship between femoral shaft torsion, hip external rotation range, and turnout. A secondary aim was to examine the relationship between femoral shaft torsion and other hip measures: hip strength, lower limb joint hypermobility, hip stability, and foot progression angle, as explanatory variables. Demographic, dance, and injury data were collected, along with physical measures of femoral shaft torsion, hip rotation range of motion, and turnout. Hip strength, control, lower limb hypermobility, and foot progression angle were also measured. Eighty female dancers, 50 with lower limb injury (20.7 ± 4.8 years of age) and 30 without lower limb injury (17.8 ± 4.1 years of age), participated in the study. There was no difference in range of femoral shaft torsion between the groups (p = 0.941). Femoral shaft torsion was weakly correlated with range of hip external rotation (r = -0.034, p = 0.384) and turnout (r = -0.066, p = 0.558). Injured dancers had a significantly longer training history than non-injured dancers (p = 0.001). It was concluded that femoral shaft torsion does not appear to be associated with the overall incidence of lower limb injury in dancers or to be a primary factor influencing extent of turnout in this population.

  10. Torsion vehicle model test for automotive vehicle

    Science.gov (United States)

    Nor, M. K. Mohd; Ho, C. S.; Ma'at, N.

    2017-04-01

    Torsion vehicle model test of Simple Structural Surfaces (SSS) model for automotive vehicle sedan is proposed in this paper to demonstrate the importance of providing continuous load path within the vehicle structures. The proposed approach is relatively easy to understand as compared to Finite Element Method (FEM). The results prove that the proposed vehicle model test is capable to show that a satisfactory load paths can five a sufficient structural stiffness within the vehicle structure. It is clearly observed that the global torsion stiffness reduces significantly when only one panel is removed from the complete SSS model. The results also five a food agreement with respect to the theoretical hypothesis as the structure is less stiff in torsion in an open section condition. The SSS model and the corresponding torsion test is obviously useful to give an overview of vehicle structural integrity. It can be potentially integrated with FEM to speed up the design process of automotive vehicle.

  11. Torsion and geometrostasis in covariant superstrings

    Energy Technology Data Exchange (ETDEWEB)

    Zachos, C.

    1985-01-01

    The covariant action for freely propagating heterotic superstrings consists of a metric and a torsion term with a special relative strength. It is shown that the strength for which torsion flattens the underlying 10-dimensional superspace geometry is precisely that which yields free oscillators on the light cone. This is in complete analogy with the geometrostasis of two-dimensional sigma-models with Wess-Zumino interactions. 13 refs.

  12. The natural evolution of internal tibial torsion.

    Science.gov (United States)

    Weiner, D S; Weiner, S D

    1979-11-01

    Faced with a confusing body of literature concerning the necessity for treatment of internal tibial torsion, the authors conducted a retrospective review of 395 consecutive cases of manifest intoeing arising from internal tibial torsion. An additional Group of 200 uninvolved teenagers served as older controls. The conclusion drawn supports an attitude of patience and observation as spontaneous resolution is to be routinely expected by skeletal maturity. Copyright 2013, SLACK Incorporated.

  13. Vaidya-like exact solutions with torsion

    CERN Document Server

    Blagojević, M

    2015-01-01

    Starting from the Oliva-Tempo-Troncoso black hole, a solution of the Bergshoeff-Hohm-Townsend massive gravity, a new class of the Vaidya-like exact solutions with torsion is constructed in the three-dimensional Poincar\\'e gauge theory. A particular subclass of these solutions is shown to possess the asymptotic conformal symmetry. The related canonical energy contains a contribution stemming from torsion.

  14. Torsion of Wandering Gallbladder following Colonoscopy

    Directory of Open Access Journals (Sweden)

    Sean R. Warfe

    2013-01-01

    Full Text Available Torsion of the gallbladder is an uncommon condition that may present as an acute abdomen. Its preoperative diagnosis can often be challenging due to its variable presentation, with specific sonographic signs seen infrequently. We describe, to our knowledge, the first case of torsion of a wandering gallbladder following a colonoscopy in a 69-year-old female who presented with acute abdominal pain after procedure. This was discovered intraoperatively, and after a subsequent cholecystectomy, she had an uncomplicated recovery.

  15. Attentional Modulation of Eye Torsion Responses

    Science.gov (United States)

    Stevenson, Scott B.; Mahadevan, Madhumitha S.; Mulligan, Jeffrey B.

    2016-01-01

    Eye movements generally have both reflexive and voluntary aspects, but torsional eye movements are usually thought of as a reflexive response to image rotation around the line of sight (torsional OKN) or to head roll (torsional VOR). In this study we asked whether torsional responses could be modulated by attention in a case where two stimuli rotated independently, and whether attention would influence the latency of responses. The display consisted of rear-projected radial "pinwheel" gratings, with an inner annulus segment extending from the center to 22 degrees eccentricity, and an outer annulus segment extending from 22 degrees out to 45 degrees eccentricity. The two segments rotated around the center in independent random walks, stepping randomly 4 degrees clockwise or counterclockwise at 60 Hz. Subjects were asked to attend to one or the other while keeping fixation steady at the center of the display. To encourage attention on one or the other segment of the display, subjects were asked to move a joystick in synchrony with the back and forth rotations of one part of the image while ignoring the other. Eye torsion was recorded with the scleral search coil technique, sampled at 500 Hz. All four subjects showed roughly 50% stronger torsion responses to the attended compared to unattended segments. Latency varied from 100 to 150 msec across subjects and was unchanged by attention. These findings suggest that attention can influence eye movement responses that are not typically under voluntary control.

  16. Are Vicinal Metal Surfaces Stable?

    DEFF Research Database (Denmark)

    Frenken, J. W. M.; Stoltze, Per

    1999-01-01

    We use effective medium theory to demonstrate that the energies of many metal surfaces are lowered when these surfaces are replaced by facets with lower-index orientations. This implies that the low-temperature equilibrium shapes of many metal crystals should be heavily faceted. The predicted ins...... instability of vicinal metal surfaces is at variance with the almost generally observed stability of these surfaces. We argue that the unstable orientations undergo a defaceting transition at relatively low temperatures, driven by the high vibrational entropy of steps....

  17. Feedback control of torsion balance in measurement of gravitational constant G with angular acceleration method.

    Science.gov (United States)

    Quan, Li-Di; Xue, Chao; Shao, Cheng-Gang; Yang, Shan-Qing; Tu, Liang-Cheng; Wang, Yong-Ji; Luo, Jun

    2014-01-01

    The performance of the feedback control system is of central importance in the measurement of the Newton's gravitational constant G with angular acceleration method. In this paper, a PID (Proportion-Integration-Differentiation) feedback loop is discussed in detail. Experimental results show that, with the feedback control activated, the twist angle of the torsion balance is limited to [Formula: see text] at the signal frequency of 2 mHz, which contributes a [Formula: see text] uncertainty to the G value.

  18. Torsional oscillations of strange stars

    Directory of Open Access Journals (Sweden)

    Mannarelli Massimo

    2014-01-01

    Full Text Available Strange stars are one of the hypothetical compact stellar objects that can be formed after a supernova explosion. The existence of these objects relies on the absolute stability of strange collapsed quark matter with respect to standard nuclear matter. We discuss simple models of strange stars with a bare quark matter surface, thus standard nuclear matter is completely absent. In these models an electric dipole layer a few hundreds Fermi thick should exist close to the star surface. Studying the torsional oscillations of the electrically charged layer we estimate the emitted power, finding that it is of the order of 1045 erg/s, meaning that these objects would be among the brightest compact sources in the heavens. The associated relaxation times are very uncertain, with values ranging between microseconds and minutes, depending on the crust thickness. Although part of the radiated power should be absorbed by the electrosphere surrounding the strange star, a sizable fraction of photons should escape and be detectable.

  19. Effect of web openings on the structural behavior of RC beams subjected to pure torsion

    Directory of Open Access Journals (Sweden)

    Abdo Taha

    2017-01-01

    Full Text Available In the construction of modern buildings, the presence of openings became a necessity nowadays in order to accommodate the many pipes and ducts required for the different services. On the other hand, the presence of these openings in RC beams affects their structural behavior. One important behavior that needs further study would be torsion. Currently, there are no guide lines available to analyze or design RC beams with web openings under pure torsion. Thus, the main objective of this research is to investigate the behavior of simply supported RC beams with openings subjected to pure torsion. In the first part of this paper, an experimental study is conducted on seven beams subjected to pure torsion loading in order to investigate the effect of the number of openings, the spacing between stirrups, and beam depth. All beams have a constant clear span length of 1800 mm and a constant beam width of 150 mm. The beams have varying opening number and stirrups arrangement as well as varying beam depth in order to investigate the effect of these parameters on the behavior of the beams. Systematic measurements such as the cracking torque, the ultimate torque, the angle of rotation of the beam at cracking, and the angle of rotation of the beam at the ultimate load are conducted for further understanding of the beam behavior under torsion. In the second part of the paper, the experimental results are compared with the numerical results obtained using the non-linear finite element analysis program, ANSYS. Good agreement between the experimental and numerical results is found.

  20. Size-dependent pull-in instability of torsional nano-actuator

    Science.gov (United States)

    Tadi Beni, Y.; Abadyan, M.

    2013-11-01

    It is well established that the mechanical behavior of ultra-small elements is size-dependent. In this paper, strain gradient continuum theory is applied for modeling the size-dependent pull-in instability of torsional nano-actuator. An actuator with a general hexagonal shape main plate is considered. The governing equation of the actuator is derived taking the effect of electrostatic and Casimir forces into account. Variation of the tilt angle as a function of the applied voltage is calculated. Moreover, the pull-in voltage and pull-in angle of the actuator are determined. Results show that when the thickness of the torsional beam is comparable with the intrinsic material length scales, size effect can substantially increase the instability voltage and angle of the rotational actuator. Moreover, the effect of the Casimir force on the size-dependent pull-in instability of the torsional actuator is discussed. Interestingly, the proposed model is able to predict the experimental results more accurately than the previous classic models and reduce the gap between previous theories and experimental measurements.

  1. The effect of stem curvature on torsional stability of a generalized cemented joint replacement system.

    Science.gov (United States)

    Hosein, Yara K; Clynick, Meghan P; McLachlin, Stewart D; King, Graham J W; Dunning, Cynthia E

    2013-12-16

    Implant loosening is a common complication that compromises the stability of joint replacement systems. Stem geometry is particularly influential in the stability of cemented implants, both before and after debonding occurs at the stem-cement interface. There are few studies assessing the effect of stem longitudinal curvature as a geometric factor in cemented implant stability. The purpose of this study was to compare the torsional stability of four generalized cemented implant stems (i.e., non-specific to joint), with varying degrees of longitudinal curvatures--zero, two, four, and six degrees. Twelve specimens of each curvature angle were potted to a depth of 20 mm using bone cement, given 24 hours to cure, and then tested in a materials testing machine. Torque was applied to the stems under monotonic loading at a rate of 2.5 degrees/min, until five degrees of rotation had occurred. There were no differences in torsional stability among the four stem curvature angles, when the magnitudes of peak torque (P=.72; 1-β = 0.13), rotation of the stem at peak torque (P=0.23; 1-β = 0.38) and work required for five degrees of stem rotation (P=.58; 1-β = 0.07) were compared. The findings from this study demonstrate that for short stems, stem curvature angles up to six degrees does not improve torsional stability when compared to the straight stem design.

  2. Hydroxyl free radical production during torsional phacoemulsification.

    Science.gov (United States)

    Aust, Steven D; Hebdon, Thomas; Humbert, Jordan; Dimalanta, Ramon

    2010-12-01

    To quantitate free radical generation during phacoemulsification using an ultrasonic phacoemulsification device that includes a torsional mode and evaluate tip designs specific to the torsional mode. Chemistry and Biochemistry Department, Utah State University, Logan, Utah, USA. Experimental study. Experiments were performed using the Infiniti Vision System and OZil handpiece. Hydroxyl radical concentrations in the aspirated irrigation solution during torsional phacoemulsification were quantitated as nanomolar malondialdehyde (nM MDA) and determined spectrophotometrically using the deoxyribose assay. The mean free radical production during phacoemulsification with torsional modality at 100% amplitude was 30.1 nM MDA ± 5.1 (SD) using a 0.9 mm 45-degree Kelman tapered ABS tip. With other tip designs intended for use with the torsional modality, free radical production was further reduced when fitted with the 0.9 mm 45-degree Kelman mini-flared ABS tip (13.2 ± 5.6 nM MDA) or the 0.9 mm 45-degree OZil-12 mini-flared ABS tip (14.3 ± 6.7 nM MDA). Although the measurements resulting from the use of the latter 2 tips were not statistically significantly different (P ≈ .25), they were different from those of the tapered tip (P<.0001). The MDA concentration in the aspirated irrigation solution using the torsional modality was approximately one half that reported for the handpiece's longitudinal modality in a previous study using the same bent-tip design (Kelman tapered, P<.0001). The level of MDA was further reduced approximately one half with torsional-specific tips. Copyright © 2010 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

  3. Ultimate Strength of Ship Hulls under Torsion

    DEFF Research Database (Denmark)

    Paik, Jeom Kee; Thayamballi, Anil K.; Pedersen, Preben Terndrup

    2001-01-01

    For a ship hull with large deck openings such as container vessels and some large bulk carriers, the analysis of warping stresses and hatch opening deformations is an essential part of ship structural analyses. It is thus of importance to better understand the ultimate torsional strength characte......For a ship hull with large deck openings such as container vessels and some large bulk carriers, the analysis of warping stresses and hatch opening deformations is an essential part of ship structural analyses. It is thus of importance to better understand the ultimate torsional strength...... characteristics of ships with large hatch openings. The primary aim of the present study is to investigate the ultimate strength characteristics of ship hulls with large hatch openings under torsion. Axial (warping) as well as shear stresses are normally developed for thin-walled beams with open cross sections...... subjected to torsion. A procedure for calculating these stresses is briefly described. As an illustrative example, the distribution and magnitude of warping and shear stresses for a typical container vessel hull cross section under unit torsion is calculated by the procedure. By theoretical and numerical...

  4. Light deflection with torsion effects caused by a spinning cosmic string

    Energy Technology Data Exchange (ETDEWEB)

    Jusufi, Kimet [State University of Tetovo, Physics Department, Tetovo (Macedonia, The Former Yugoslav Republic of)

    2016-06-15

    Using a new geometrical method introduced by Werner, we find the deflection angle in the weak limit approximation by a spinning cosmic string in the context of the Einstein-Cartan (EC) theory of gravity. We begin by adopting the String-Randers optical metric, then we apply the Gauss-Bonnet theorem to the optical geometry and derive the leading terms of the deflection angle in the equatorial plane. Calculation shows that light deflection is affected by the intrinsic spin of the cosmic string and torsion. (orig.)

  5. Light Deflection with Torsion Effects Caused by a Spinning Cosmic String

    CERN Document Server

    Jusufi, Kimet

    2016-01-01

    Using a new geometrical method introduced by Werner, we find the deflection angle in the weak limit approximation by a spinning cosmic string in the context of the Einstein-Cartan (EC) theory of gravity. We begin by adopting the String-Randers optical metric, then we apply the Gauss-Bonnet theorem to the optical geometry and derive the leading terms of the deflection angle in the equatorial plane. Calculations shows that light deflection is affected by the intrinsic spin of the cosmic string and torsion.

  6. TIBIAL TORSION; DOES IT DIFFER IN CHILDREN WITH CONGENITAL TALIPES EQUINOVARUS (CTEV COMPARED TO NORMAL ONES?

    Directory of Open Access Journals (Sweden)

    Amol Sanap, Tushar Chaudhari, Binoti Sheth, Dhruvilkumar Gandhi, Kaustubh Gate, Arun AA

    2015-10-01

    Full Text Available Background: Congenital talipes equinovarus (CTEV or clubfoot is one of the commonest congenital orthopaedic conditions requiring intensive treatment. A typical clubfoot consists of a deformed foot in equinus ,varus, adduction. In some cases a cavus component is also there. Tibial torsion is the angle between the transverse axes of the proximal and distal tibial articular surfaces. Controversy exists concerning the presence or absence of excessive medial or internal tibial torsion in CTEV. Materials & Methods: A cross sectional study was done of thirty consenting patients with CTEV and thirty children with injuries not involving the tibia or fibula selected by convenience sampling attending the orthopaedic clinic of a tertiary care hospital of Western Maharashtra . We measured the angular difference between the proximal and distal posterior tibial planes as defined by ultrasound scans thus minimising the error introduced by the posterior shifting of lower end fibula in the fibular notch after manipulative correction. The data was entered in excel and appropriate statistic test was applied. Results: The mean external torsion of the tibia in children with CTEV was 18 degrees (standard deviation 2.7, which was significantly less than the mean external torsion of tibia in normal children (38.13 degrees; standard deviation 9.194 (p<0.05. Conclusions: The children with CTEV have a relative tibial intorsion, as compared to normal children.

  7. Torsional rigidity of submanifolds with controlled geometry

    DEFF Research Database (Denmark)

    Hurtado, Ana; Markvorsen, Steen; Palmer, Vicente

    2009-01-01

    We prove explicit upper and lower bounds for the torsional rigidity of extrinsic domains of submanifolds ^m$ with controlled radial mean curvature in ambient Riemannian manifolds ^n$ with a pole $ and with sectional curvatures bounded from above and from below, respectively. These bounds are given...... in terms of the torsional rigidities of corresponding Schwarz symmetrizations of the domains in warped product model spaces. Our main results are obtained using methods from previously established isoperimetric inequalities, as found in e.g. [MP4] and [MP5]. As in [MP4] we also characterize the geometry...... of those situations in which the bounds for the torsional rigidity are actually attained and study the behavior at infinity of the so-called geometric average of the mean exit time for Brownian motion....

  8. Torsional fatigue resistance of pathfinding instruments manufactured from several nickel-titanium alloys.

    Science.gov (United States)

    Alcalde, M P; Duarte, M A H; Bramante, C M; Tanomaru-Filho, M; Vasconcelos, B C; Só, M V R; Vivan, R R

    2017-11-24

    To evaluate the torsional properties of pathfinding nickel-titanium (NiTi) rotary instruments manufactured from several NiTi alloys, ProGlider (M-wire), Hyflex GPF (conventional NiTi Wire and controlled memory wire), Logic (conventional NiTi wire and controlled memory wire) and Mtwo (conventional NiTi wire). A total of 56 NiTi instruments from Glidepath rotary systems (n = 8) were used: Logic (size 25, .01 taper), Logic CM (size 25, .01 taper), ProGlider (size 16, .02 taper), Hyflex GPF (size 15, .01 taper), Hyflex GPF CM (size 15, .02 taper; size 20, .02 taper) and Mtwo (size 10, .04 taper). The torsion tests were performed based on ISO 3630-1 (1992). Three millimetres of each instrument tip was clamped to a small load cell by a lever arm linked to the torsion axis. Data were analysed using a one-way analysis of variance (anova) and Tukey test with a significance level at a = 5%. The Logic size 25, .01 taper had significantly higher torsional strength values (P Hyflex GPF size 15, .01 taper and size 15, .02 taper (P Hyflex GPF size 15, .01 taper and size 15, .02 taper (P Hyflex GPF groups (size 15, .01 taper; size 15, .02 taper; size 20, .02 taper). In relation to the angle of rotation, Logic CM size 25, .01 taper and Hyflex GPF size 15, .01 taper had the highest angle values (P < 0.05). The ProGlider had the lowest angle values in comparison with all the groups (P < 0.05) followed by Mtwo size 10, .04 taper. The Logic size 25, .01 taper had significantly higher angle of rotation values than ProGlider and Mtwo size 10, .04 taper (P < 0.05). The Logic size 25, .01 taper instrument made of conventional NiTi alloy had the highest torsional strength of all instruments tested. In addition, the ProGlider instrument manufactured from M-Wire alloy had the lowest angle of rotation to fracture in comparison with the other instruments. © 2017 International Endodontic Journal. Published by John Wiley & Sons Ltd.

  9. Torsional wave propagation in solar tornadoes

    Science.gov (United States)

    Vasheghani Farahani, S.; Ghanbari, E.; Ghaffari, G.; Safari, H.

    2017-03-01

    Aims: We investigate the propagation of torsional waves in coronal structures together with their collimation effects in the context of magnetohydrodynamic (MHD) theory. The interplay of the equilibrium twist and rotation of the structure, e.g. jet or tornado, together with the density contrast of its internal and external media is studied to shed light on the nature of torsional waves. Methods: We consider a rotating magnetic cylinder embedded in a plasma with a straight magnetic field. This resembles a solar tornado. In order to express the dispersion relations and phase speeds of the axisymmetric magnetohydrodynamic waves, the second-order thin flux tube approximation is implemented for the internal medium and the ideal MHD equations are implemented for the external medium. Results: The explicit expressions for the phase speed of the torsional wave show the modification of the torsional wave speed due to the equilibrium twist, rotation, and density contrast of the tornado. The speeds could be either sub-Alfvénic or ultra-Alfvénic depending on whether the equilibrium twist or rotation is dominant. The equilibrium twist increases the phase speed while the equilibrium rotation decreases it. The good agreement between the explicit versions for the phase speed and that obtained numerically proves adequate for the robustness of the model and method. The density ratio of the internal and external media also play a significant role in the speed and dispersion. Conclusions: The dispersion of the torsional wave is an indication of the compressibility of the oscillations. When the cylinder is rotating or twisted, in contrast to when it only possesses a straight magnetic field, the torsional wave is a collective mode. In this case its phase speed is determined by the Alfvén waves inside and outside the tornado.

  10. The Effect of Taper Angle and Spline Geometry on the Initial Stability of Tapered, Splined Modular Titanium Stems.

    Science.gov (United States)

    Pierson, Jeffery L; Small, Scott R; Rodriguez, Jose A; Kang, Michael N; Glassman, Andrew H

    2015-07-01

    Design parameters affecting initial mechanical stability of tapered, splined modular titanium stems (TSMTSs) are not well understood. Furthermore, there is considerable variability in contemporary designs. We asked if spline geometry and stem taper angle could be optimized in TSMTS to improve mechanical stability to resist axial subsidence and increase torsional stability. Initial stability was quantified with stems of varied taper angle and spline geometry implanted in a foam model replicating 2cm diaphyseal engagement. Increased taper angle and a broad spline geometry exhibited significantly greater axial stability (+21%-269%) than other design combinations. Neither taper angle nor spline geometry significantly altered initial torsional stability. Copyright © 2015 Elsevier Inc. All rights reserved.

  11. Spontaneous lung lobe torsion in two pugs.

    Science.gov (United States)

    Rooney, M B; Lanz, O; Monnet, E

    2001-01-01

    Two, young adult, male pugs presented for spontaneous left-cranial lung lobe torsions. Clinical signs associated with these two cases included increased weakness, increased respiratory effort, tachypnea, acute collapse, lethargy, anorexia, and cyanosis. The torsed lung lobes were excised using a thoracoabdominal stapling device without detorsing the lobes. Both dogs recovered uneventfully, and at least one year postoperatively, no clinical abnormalities were noted by their owners. Results of this report suggest that spontaneous lung lobe torsion in pugs occurs and should be a differential diagnosis for pugs with increased respiratory effort, tachypnea, nonproductive cough, acute collapse, cyanosis, and lethargy. Surgical excision may be curative.

  12. Torsional Performance of Wind Turbine Blades

    DEFF Research Database (Denmark)

    Branner, Kim; Berring, Peter; Berggreen, Christian

    2007-01-01

    The present work investigates how well different finite element modeling techniques can predict bending and torsion behavior of a wind turbine blade. Two shell models are investigated. One model has element offsets and the other has the elements at the mid-thickness surfaces of the model. The last...... two models investigated use a combination of shell and solid elements. The results from the numerical investigations are compared with measurements from testing of a section of a full-scale wind turbine blade. It is found that only the combined shell/solid models give reliable results in torsion. Both...

  13. Tussive syncope in a pug with lung-lobe torsion

    Science.gov (United States)

    Davies, John A.; Snead, Elisabeth C.R.; Pharr, John W.

    2011-01-01

    The most common presenting clinical signs of lung-lobe torsion include dyspnea, tachypnea, lethargy, and anorexia. Tussive syncope secondary to lung-lobe torsion has not been documented. This article describes the presentation, diagnosis, management, and outcome of a pug with tussive syncope secondary to lung-lobe torsion. PMID:22131584

  14. The relationship between torsional rigidity and bending strength ...

    African Journals Online (AJOL)

    The modulus of rigidity, G, and bending moment of elasticity, MOE, of SA pine are evaluated from a direct torsion test and bending tests. Specimens were subjected to a series of tests with the view to determining direct torsional rigidity, apparent bending modulus of elasticity and pure bending modulus of elasticity. Torsional ...

  15. Testicular torsion: case report | Kuremu | East African Medical Journal

    African Journals Online (AJOL)

    This is a report of bilateral testicular torsion. The objective of the report is to highlight the serious implications of misdiagnosis of testicular torsion. Other than loss of the testis due to necrosis in unilateral torsion, immunological damage of the opposite testis occurs. Early, accurate diagnosis, and institution of the appropriate ...

  16. Acute and intermittent testicular torsion: Analysis of presentation ...

    African Journals Online (AJOL)

    2015-11-18

    Nov 18, 2015 ... Background: Testicular torsion compromises the blood supply to the testes and may result in testicular loss or damage if not dealt with promptly. It can occur either as acute testicular torsion (ATT) or intermittent testicular torsion (ITT). This study examines the presentation, management, and outcome of adult ...

  17. Torsion of the gallbladder: a case report

    Directory of Open Access Journals (Sweden)

    Ijaz Samia

    2008-07-01

    Full Text Available Abstract Introduction Torsion of the gallbladder is a rare condition that most commonly affects the elderly. Pre-operative diagnosis is the exception rather than the rule. Any delay in treatment can be fatal as the gallbladder may rupture, leading to biliary peritonitis. Case presentation We present the case of an 80-year-old woman who was admitted with right upper quadrant pain initially thought to be secondary to acute cholecystitis. Subsequent ultrasound and computed tomography scans of the abdomen revealed signs suggestive of acute cholecystitis but neither modality detected any gallstones. As the patient's symptoms failed to resolve on conservative management, she was taken to theatre for an open cholecystectomy. Intra-operatively, the gallbladder had undergone complete torsion and appeared gangrenous. A routine cholecystectomy followed and she recovered from the operation without incident. Conclusion It is rare to diagnose torsion of the gallbladder pre-operatively despite advances in diagnostic imaging. However, this differential diagnosis should be borne in mind particularly in the elderly patient, without proven gallstones, who fails to improve on conservative management. An emergency cholecystectomy is indicated in the event of diagnosing torsion of the gallbladder to avert the potentially lethal sequelae of biliary peritonitis.

  18. Torsion of the gallbladder: a case report.

    Science.gov (United States)

    Ijaz, Samia; Sritharan, Kaji; Russell, Neil; Dar, Manzoor; Bhatti, Tahir; Ormiston, Michael

    2008-07-24

    Torsion of the gallbladder is a rare condition that most commonly affects the elderly. Pre-operative diagnosis is the exception rather than the rule. Any delay in treatment can be fatal as the gallbladder may rupture, leading to biliary peritonitis. We present the case of an 80-year-old woman who was admitted with right upper quadrant pain initially thought to be secondary to acute cholecystitis. Subsequent ultrasound and computed tomography scans of the abdomen revealed signs suggestive of acute cholecystitis but neither modality detected any gallstones. As the patient's symptoms failed to resolve on conservative management, she was taken to theatre for an open cholecystectomy. Intra-operatively, the gallbladder had undergone complete torsion and appeared gangrenous. A routine cholecystectomy followed and she recovered from the operation without incident. It is rare to diagnose torsion of the gallbladder pre-operatively despite advances in diagnostic imaging. However, this differential diagnosis should be borne in mind particularly in the elderly patient, without proven gallstones, who fails to improve on conservative management. An emergency cholecystectomy is indicated in the event of diagnosing torsion of the gallbladder to avert the potentially lethal sequelae of biliary peritonitis.

  19. Fermion Helicity Flip Induced by Torsion Field

    OpenAIRE

    Capozziello, S.; Iovane, G.; Lambiase, G.; Stornaiolo, C.

    1999-01-01

    We show that in theories of gravitation with torsion the helicity of fermion particles is not conserved and we calculate the probability of spin flip, which is related to the anti-symmetric part of affine connection. Some cosmological consequences are discussed.

  20. Plant-based torsional actuator with memory

    Science.gov (United States)

    Nayomi Plaza; Samuel L. Zelinka; Don S. Stone; Joseph E. Jakes

    2013-01-01

    A bundle of a few loblolly pine (Pinus taeda) cells are moisture-activated torsional actuators that twist multiple revolutions per cm length in direct proportion to moisture content. The bundles generate 10 N m kg􀀀1 specific torque during both twisting and untwisting, which is higher than an electric motor. Additionally, the bundles exhibit a moisture-...

  1. Regional assessment of left ventricular torsion by CMR tagging

    Directory of Open Access Journals (Sweden)

    Marcus J Tim

    2008-05-01

    Full Text Available Abstract Purpose To introduce a standardized method for calculation of left ventricular torsion by CMR tagging and to determine the accuracy of torsion analysis in regions using an analytical model. Methods Torsion between base and apex, base and mid, and mid and apex levels was calculated using CSPAMM tagging and Harmonic Phase tracking. The accuracy of torsion analysis on a regional basis (circumferential segments and transmural layers was analyzed using an analytical model of a deforming cylinder with a displaced axis of rotation (AoR. Regional peak torsion values from twelve healthy volunteers calculated by the described method were compared to literature. Results The deviation from the analytical torsion per % AoR-displacement (of the radius was 0.90 ± 0.44% for the circumferential segments and only 0.05% for the transmural layers. In the subjects, circumferentially, anterolateral torsion was larger than inferior (12.4 ± 3.9° vs. 5.0 ± 3.3°, N.S.. Transmurally, endocardial torsion was smaller than epicardial (7.5 ± 1.3° vs. 8.0 ± 1.5°, p Conclusion Variability in the position of the AoR causes a large variability in torsion in circumferential segments. This effect was negligible for global torsion, and torsion calculated in transmural layers. Results were documented for the healthy human heart and are in agreement with data from literature.

  2. Inelastic Seismic Torsional Behaviour of Elevated Tanks

    Science.gov (United States)

    DUTTA, S. C.; JAIN, S. K.; MURTY, C. V. R.

    2001-04-01

    Torsional failure of elevated tanks has occurred in past earthquakes. The overall axisymmetric structural geometry and mass distribution of such structures may leave only a small accidental eccentricity between centre of stiffness and centre of mass. Such a small accidental eccentricity is not expected to cause a torsional failure. This paper studies the possibility of amplified torsional behaviour of elevated water tanks due to such small accidental eccentricity in inelastic range through detailed case studies; using two simple idealized systems with two coupled lateral-torsional degrees of freedom and, strength-deteriorating and elasto-plastic hysteresis models. The systems are capable of retaining the characteristics of two extreme categories of water tanks namely, (a) tanks on staging with less number of columns and panels and (b) tanks on staging with large number of columns and panels. The study shows that the presence of a small eccentricity may lead to localized unsymmetrical yielding in some of the reinforced concrete staging elements. This may lead to progressive strength deterioration through successive yieldings in same elements under cyclic loading during earthquakes. Such localized strength drop may increasingly develop large strength eccentricity resulting in large localized inelastic displacement and ductility demand, leading to failure. These observations are also verified for a real-life example elevated tank. The tanks supported on staging with fewer columns and panels are found to have greater torsional vulnerability. The tanks located near a fault are found to be vulnerable under near-fault pulses with a large duration compared to the lateral period of tank.

  3. Bending-torsional flutter of a cantilevered pipe conveying fluid with an inclined terminal nozzle

    Science.gov (United States)

    Firouz-Abadi, R. D.; Askarian, A. R.; Kheiri, M.

    2013-06-01

    Stability analysis of a horizontal cantilevered pipe conveying fluid with an inclined terminal nozzle is considered in this paper. The pipe is modelled as a cantilevered Euler-Bernoulli beam, and the flow-induced inertia, Coriolis and centrifugal forces along the pipe as well as the follower force induced by the jet-flow are taken into account. The governing equations of the coupled bending-torsional vibrations of the pipe are obtained using extended Hamilton's principle and are then discretized via the Galerkin method. The resulting eigenvalue problem is then solved, and several cases are examined to determine the effect of nozzle inclination angle, nozzle aspect ratio, mass ratio and bending-to-torsional rigidity ratio on flutter speed of the system.

  4. Carbon nanotube torsional springs for regenerative braking systems

    Science.gov (United States)

    Liu, Sanwei; Martin, Corbin; Lashmore, David; Schauer, Mark; Livermore, Carol

    2015-10-01

    The modeling and demonstration of large stroke, high energy density and high power density torsional springs based on carbon nanotube (CNT) yarns is reported, as well as their application as energy-storing actuators for regenerative braking systems. An originally untwisted CNT yarn is cyclically loaded and unloaded in torsion, with the maximum rotation angle increasing incrementally until failure. The measured average extractable energy density values are 2.9 kJ kg-1  ±  1.2 kJ kg-1 and 3.4 kJ kg-1  ±  0.4 kJ kg-1 for 1-ply CNT yarns and 2-ply CNT yarns, respectively. Additionally, a regenerative braking system is demonstrated to capture the kinetic energy of a wheel and store it as elastic energy in twisted CNT yarns. When the yarn’s twist is released, the stored energy reaccelerates the wheel. The measured energy and mean power densities of the CNT yarns in the simple regenerative braking setup are on average 3.3 kJ kg-1 and 0.67 kW kg-1, respectively, with maximum measured values of up to 4.7 kJ kg-1 and 1.2 kW kg-1, respectively. A slightly lower energy density of up to 1.2 kJ kg-1 and a 0.29 kW kg-1 mean power density are measured for CNT yarns in a more complex setup that mimics a unidirectional rotating regenerative braking mechanism.

  5. Intramolecular surfaces for vicinal proton-proton coupling constants 3JHH

    Science.gov (United States)

    Díez, Ernesto; Esteban, Angel L.; San Fabián, Jesús; Galache, María P.; Casanueva, Jorge; Contreras, Rubén H.

    2014-08-01

    Equations for the intramolecular surfaces of the 3JHH coupling constants in ethane, ethylene, and acetylene are formulated, and the corresponding coefficients are estimated from calculations at the DFT/B3LYP level. The chosen variables are changes in bond lengths, in the torsion angle φ between the coupled protons Ha and Hb, in bond angles, and in dihedral angles. The 3JHH surface of ethane is formulated as an extended Karplus equation with the coefficients of a truncated Fourier series on the torsion angle φ expanded as second-order Taylor series in the chosen variables taking into account the invariance of 3JHH under reflections and rotations of nuclear coordinates. Partial vibrational contributions from linear and square terms corresponding to changes in the geometry of the Ha - Ca - Cb - Hb fragment are important while those from cross terms are small with a few exceptions. The 3JHH surface of ethane is useful to predict contributions to 3JHH from changes in local geometry of derivatives but vibrational contributions are predicted less satisfactorily. The predicted values at the B3LYP/BS2 level of the 3JHH couplings (vibrational contributions at 300 K) from equilibrium geometries are 9.79 (-0.17) for acetylene, and 17.08 (1.93) and 10.73(0.93) for the trans and cis couplings of ethylene.

  6. From vicinal to rough crystal surfaces

    Science.gov (United States)

    Balibar, S.; Guthmann, C.; Rolley, E.

    1993-06-01

    One generally expects the properties of a vicinal surface to be independent of the existence of steps as soon as these steps overlap, i.e. when their mutual distance is smaller than their width. By using the roughening theory by Nozières and Gallet [1], we show that, at least for surfaces weakly coupled to the lattice, this overlap occurs for distances significantly larger than the commonly defined width. Our prediction is supported by an analysis of the various measurements of the angular variation of the surface stiffness of helium crystals, which were performed by Wolf et al. [2], Andreeva et al. [3] and Babkin et al. [4]. As a consequence, the interaction between crystal steps should be studied on vicinal surfaces with a much smaller tilt angle than previously thought. This article is also an opportunity to return to the relation between the step width and the correlation length on smooth surfaces, as well as to the treatment of the various finite size effects which occur in the problem of roughening. We finally reconsider how the weak coupling hypothesis applies to the case of helium crystals. On s'attend généralement à ce que les propriétés d'une surface vicinale ne soient plus contrôlées par l'existence des marches lorsque celles-ci se recouvrent, donc lorsque leur distance mutuelle devient inférieure à leur largeur. En reprenant la théorie de la transition rugueuse élaborée par Nozières et Gallet [1], nous montrons que, pour des surfaces faiblement couplées au réseau cristallin, ce recouvrement doit se produire pour des distances nettement plus grandes que la largeur (telle qu'elle est habituellement définie). Notre prédiction est confirmée par l'analyse des différentes mesures de la variation angulaire de la rigidité de surface des cristaux d'hélium réalisées par Wolf et al. [2], Andreeva et al. [3] and Babkin et al. [4]. Il s'ensuit que l'étude de l'interaction entre marches cristallines doit être effectuée sur des surfaces

  7. Habitat--Monterey Canyon and Vicinity, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the habitat map of the seafloor of the Monterey Canyon and Vicinity map area, California. The vector data file is included in...

  8. Contours--Monterey Canyon and Vicinity, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents bathymetric contours for several seafloor maps of the Monterey Canyon and Vicinity map area, California. The raster data file is...

  9. Torsion and transverse bending of cantilever plates

    Science.gov (United States)

    Reissner, Eric; Stein, Manuel

    1951-01-01

    The problem of combined bending and torsion of cantilever plates of variable thickness, such as might be considered for solid thin high-speed airplane or missile wings, is considered in this paper. The deflections of the plate are assumed to vary linearly across the chord; minimization of the potential energy by means of the calculus of variations then leads to two ordinary linear differential equations for the bending deflections and the twist of the plate. Because the cantilever is analyzed as a plate rather than as a beam, the effect of constraint against axial warping in torsion is inherently included. The application of this method to specific problems involving static deflection, vibration, and buckling of cantilever plates is presented. In the static-deflection problems, taper and sweep are considered.

  10. Torsional Kinematic Model for Concentric Tube Robots.

    Science.gov (United States)

    Dupont, Pierre E; Lock, Jesse; Butler, Evan

    2009-05-12

    A recent approach to steerable needle design is based on combining pre-curved tubes concentrically. By rotating and extending the tubes with respect to each other, the position and orientation of the needle tip, as well as the shape of the inserted length, can be controlled. Prior models neglected torsional twisting in the curved portions of the tubes. This paper presents a mechanics model that includes torsion, applies to any number of tubes and allows curvature and stiffness to vary with arc length. While the general model is comprised of differential equations, an analytic solution is given for two tubes of constant curvature. This solution enables analytic prediction of "snap through" instability based on a single dimensionless parameter. Simulation and experiments are used to illustrate the results.

  11. Torsion of a giant mesenteric lipoma

    Energy Technology Data Exchange (ETDEWEB)

    Wolko, Jonathan D.; Rosenfeld, David L.; Lazar, Michael J.; Underberg-Davis, Sharon J. [Department of Radiology, University of Medicine and Dentistry of New Jersey, Robert Wood Johnson Medical School, P.O. Box 19, New Brunswick, NJ 08903-0019 (United States)

    2003-01-01

    Mesenteric lipoma is a rare benign neoplastic condition that can grow to be very large and mimic other midgut fatty tumors. These benign tumors can cause various gastrointestinal symptoms such as obstruction and abdominal pain. We report the case of a 9-year-old boy who presented with a small bowel obstruction caused by torsion of a large mesenteric lipoma. This is an important but unusual tumor and should be considered in the differential of fatty lesions within the mesentery. (orig.)

  12. Is Torsion a Fundamental Physical Field?

    CERN Document Server

    Lecian, Orchidea Maria; Montani, Giovanni

    2016-01-01

    The local Lorentz group is introduced in flat space-time, where the resulting Dirac and Yang-Mills equations are found, and then generalized to curved space-time: if matter is neglected, the Lorentz connection is identified with the contortion field, while, if matter is taken into account, both the Lorentz connection and the spinor axial current are illustrated to contribute to the torsion of space-time.

  13. Electrostatically actuated torsional resonant sensors and switches

    KAUST Repository

    Younis, Mohammad I.

    2016-12-29

    Embodiments in accordance of a torsional resonant sensor disclosure is configured to actuate a beam structure using electrostatic actuation with an AC harmonic load (e.g., AC and DC voltage sources) that is activated upon detecting a particular agent having a mass above a predefined level. In various embodiments, the beam structure may be different types of resonant structures that is at least partially coated or layered with a selective material.

  14. Piezoelectric d36 in-plane shear-mode of lead-free BZT-BCT single crystals for torsion actuation

    Science.gov (United States)

    Berik, P.; Chang, W.-Y.; Jiang, X.

    2017-01-01

    We report the study of piezoelectric direct torsion actuation mechanism using lead-free piezoelectric d36 in-plane shear-mode BZT-BCT single crystals. The generated angle of twist of the piezoelectric torsion actuator was obtained from the transverse deflection measurement using a laser vibrometer. The bi-morph torsional actuator, consisting of two lead-free piezoelectric BZT-BCT in-plane shear-mode single crystals with a giant piezoelectric d36 shear strain coefficient of 1590 pC/N, provided a rate of twist of 34.12 mm/m under a quasi-static 15 V drive. The experimental benchmark was further modelled and verified by the ANSYS software using three dimensional (3D) piezoelectric finite elements. The experimental results revealed that lead-free piezoelectric BZT-BCT d36-mode single crystal is a superior candidate for piezoelectric torsion actuation. This lead-free piezoelectric BZT-BCT d36-mode torsion actuator can be effectively applied in torsional deformation control by taking into account the environmental considerations.

  15. the Analysis of Coupled Lateral Torsional Vibrations

    Directory of Open Access Journals (Sweden)

    Tomasz Szolc

    2000-01-01

    Full Text Available In the paper, dynamic investigations of the rotor shaft systems are performed by means of the discrete-continuous mechanical models. In these models the rotor shaft segments are represented by the rotating cylindrical flexurally and torsionally deformable continuous viscoelastic elements. These elements are mutually connected according to the structure of the real system in the form of a stepped shaft which is suspended on concentrated inertial viscoelastic supports of linear or non-linear characteristics. At appropriate shaft crosssections, by means of massless membranes, there are attached rigid rings representing rotors, disks, gears, flywheels and others. The proposed model enables us to investigate coupled linear or non-linear lateral torsional Vibrations of the rotating systems in steady-state and transient operating conditions. As demonstrative examples, for the steam turbo-compressor under coupled lateral torsional vibrations, the transient response due to a blade falling out from the turbine rotor as well as the steady-state response in the form of parametric resonance caused by residual unbalances are presented.

  16. Perinatal testicular torsion and medicolegal considerations.

    Science.gov (United States)

    Massoni, F; Troili, G M; Pelosi, M; Ricci, S

    2014-06-01

    Perinatal testicular torsion (PTT) is a very complex condition because of rarity of presentation and diagnostic and therapeutic difficulties. In presence of perinatal testicular torsion, the involvement of contralateral testis can be present also in absence of other indications which suggest the bilateral involvement; therefore, occurrences supported by literature do not exclude the use of surgery to avoid the risk of omitted or delayed diagnosis. The data on possible recovery of these testicles are not satisfactory, and treatment consists of an observational approach ("wait-and-see") or an interventional approach. The hypothesis of randomized clinical trials seems impracticable because of rarity of disease. The authors present a case of PTT, analyzing injuries due to clinical and surgical management of these patients, according to medicolegal profile. The delayed diagnosis and the choice of an incorrect therapeutic approach can compromise the position of healthcare professionals, defective in terms of skill, prudence and diligence. Endocrine insufficiency is an unfortunate event. The analysis of literature seems to support, because of high risk, a surgical approach aimed not only at resolution of unilateral pathology or prevention of a relapse, but also at prevention of contralateral testicular torsion.

  17. Isolated Fallopian Tube Torsion in Adolescents

    Directory of Open Access Journals (Sweden)

    S. Rajaram

    2013-01-01

    Full Text Available Background. Fallopian tube torsion is a rare cause of acute abdomen, occurring commonly in females of reproductive age. It lacks pathognomonic symptoms, signs, or imaging features, thus causing delay in surgical intervention. Case. We report two cases of isolated fallopian tube torsion in adolescent girls. In the first case a 19-year-old patient presented with acute pain in the left iliac region associated with episodes of vomiting for one day and mild tenderness on examination. Laparoscopy revealed left sided twisted fallopian tube associated with hemorrhagic cyst of ovary. The tube was untwisted and salvaged. In another case an 18-year-old virgin girl presented with similar complaints since one week, associated with mild tenderness in the lower abdomen and tender cystic mass on per rectal examination. On laparoscopy right twisted fallopian tube associated with a paratubal cyst was found. Salpingectomy was done as the tube was gangrenous. Conclusion. Fallopian tube torsion, though rare, should be considered in women of reproductive age with unilateral pelvic pain. Early diagnostic laparoscopy is important for an accurate diagnosis and could salvage the tube.

  18. Isolated Penile Torsion in Brothers: A Case Report

    Directory of Open Access Journals (Sweden)

    Metin Gunduz

    2012-04-01

    Full Text Available Penile torsion can be congenital and associated with hypospadias and chordee, or can be acquired after circumcision. The incidence of isolated neonatal penile torsion was 1.7 to 27% in the literature. The majority were between 10 and deg; and 20 and deg;. Generally, torsion was to the left in cases. The techniques for correction of penile torsion described in the literature are penile de-gloving and reattaching of skin, resection of Buck's fascia incising the base of the penis and removing angular ellipses of corporeal tissue with subsequent plication of tunica, and dorsal dartos flap rotation in severe cases. In conclusion, penile torsion may be familial. Therefore, brothers should be examined carefully. The degloving and realignment technique is successful in isolated penile torsion. [Arch Clin Exp Surg 2012; 1(2.000: 122-124

  19. Nonminimal couplings, gravitational waves, and torsion in Horndeski's theory

    Science.gov (United States)

    Barrientos, José; Cordonier-Tello, Fabrizio; Izaurieta, Fernando; Medina, Perla; Narbona, Daniela; Rodríguez, Eduardo; Valdivia, Omar

    2017-10-01

    The Horndeski Lagrangian brings together all possible interactions between gravity and a scalar field that yield second-order field equations in four-dimensional spacetime. As originally proposed, it only addresses phenomenology without torsion, which is a non-Riemannian feature of geometry. Since torsion can potentially affect interesting phenomena such as gravitational waves and early universe inflation, in this paper we allow torsion to exist and propagate within the Horndeski framework. To achieve this goal, we cast the Horndeski Lagrangian in Cartan's first-order formalism and introduce wave operators designed to act covariantly on p -form fields that carry Lorentz indices. We find that nonminimal couplings and second-order derivatives of the scalar field in the Lagrangian are indeed generic sources of torsion. Metric perturbations couple to the background torsion, and new torsional modes appear. These may be detected via gravitational waves but not through Yang-Mills gauge bosons.

  20. Radiographic evaluation of femoral torsion and correlation with computed tomographic techniques in labrador retrievers with and without cranial cruciate ligament disease.

    Science.gov (United States)

    Mostafa, Ayman A; Griffon, Dominique J; Thomas, Michael W; Constable, Peter D

    2014-07-01

    To (1) develop a technique to determine the anteversion angle (AA) of the femur on a single radiograph; (2) determine the correlation between this technique and other published radiographic and computed tomographic (CT) methods; and (3) compare the diagnostic outcome of these methods in determining the level at which femoral torsion occurred in Labrador Retrievers with cranial cruciate ligament (CCL) deficiency. Cross-sectional clinical study. Mature pure-bred Labrador Retrievers (n = 30). Pelvic limbs (n = 28) of 14 dogs without CCL deficiency were classified as control, whereas limbs of 16 dogs (18 limbs) with CCL deficiency were considered as diseased. Femoral torsion was evaluated using radiography and CT and variables were compared among limb groups by use of a mixed-model ANOVA, with P < .05 considered significant. There was a significant association between biplanar and lateral plane AAs but neither correlated with CT assessment of femoral torsion. On CT, a significant correlation was identified between overall AA and each of the distal, proximal, and femoral head trochanteric angles. Biplanar and lateral plane AAs did not differ between normal and CCL deficient limbs. On CT, overall and distal AAs were increased in CCL deficient limbs compared to control. Biplanar determination of femoral torsion can be estimated based on a single lateral radiograph but the results will be inaccurate as only CT identified and localized the site of femoral torsion. © Copyright 2014 by The American College of Veterinary Surgeons.

  1. Design of a nonlinear torsional vibration absorber

    Science.gov (United States)

    Tahir, Ammaar Bin

    Tuned mass dampers (TMD) utilizing linear spring mechanisms to mitigate destructive vibrations are commonly used in practice. A TMD is usually tuned for a specific resonant frequency or an operating frequency of a system. Recently, nonlinear vibration absorbers attracted attention of researchers due to some potential advantages they possess over the TMDs. The nonlinear vibration absorber, or the nonlinear energy sink (NES), has an advantage of being effective over a broad range of excitation frequencies, which makes it more suitable for systems with several resonant frequencies, or for a system with varying excitation frequency. Vibration dissipation mechanism in an NES is passive and ensures that there is no energy backflow to the primary system. In this study, an experimental setup of a rotational system has been designed for validation of the concept of nonlinear torsional vibration absorber with geometrically induced cubic stiffness nonlinearity. Dimensions of the primary system have been optimized so as to get the first natural frequency of the system to be fairly low. This was done in order to excite the dynamic system for torsional vibration response by the available motor. Experiments have been performed to obtain the modal parameters of the system. Based on the obtained modal parameters, the design optimization of the nonlinear torsional vibration absorber was carried out using an equivalent 2-DOF modal model. The optimality criterion was chosen to be maximization of energy dissipation in the nonlinear absorber attached to the equivalent 2-DOF system. The optimized design parameters of the nonlinear absorber were tested on the original 5-DOF system numerically. A comparison was made between the performance of linear and nonlinear absorbers using the numerical models. The comparison showed the superiority of the nonlinear absorber over its linear counterpart for the given set of primary system parameters as the vibration energy dissipation in the former is

  2. Regenerative braking systems with torsional springs made of carbon nanotube yarn

    Science.gov (United States)

    Liu, S.; Martin, C.; Lashmore, D.; Schauer, M.; Livermore, C.

    2014-11-01

    The demonstration of large stroke, high energy density and high power density torsional springs based on carbon nanotube (CNT) yarns is reported, as well as their application as an energy-storing actuator for regenerative braking systems. Originally untwisted CNT yarn is cyclically loaded and unloaded in torsion, with the maximum rotation angle increasing until failure. The maximum extractable energy density is measured to be as high as 6.13 kJ/kg. The tests also reveal structural reorganization and hysteresis in the torsional loading curves. A regenerative braking system is built to capture the kinetic energy of a wheel and store it as elastic energy in twisted CNT yarns. When the yam's twist is released, the stored energy reaccelerates the wheel. The measured energy and mean power densities of the CNT yarns in the simple regenerative braking system are up to 4.69 kJ/kg and 1.21 kW/kg, respectively. A slightly lower energy density of up to 1.23 kJ/kg and a 0.29 kW/kg mean power density are measured for the CNT yarns in a more complex system that mimics a unidirectional rotating regenerative braking mechanism. The lower energy densities for CNT yarns in the regenerative braking systems as compared with the yarns themselves reflect the frictional losses of the regenerative systems.

  3. Surface strain gradient effects in the torsion of a circular bar with radial cracks

    Science.gov (United States)

    Xu, Yang; Wang, Xu

    2016-12-01

    We study the contribution of surface strain gradient elasticity to the Saint-Venant torsion problem of a circular cylinder containing a radial crack. The surface strain gradient elasticity is incorporated by using an enriched version of the continuum-based surface/interface model of Gurtin and Murdoch. By using Green's function method, the original boundary value problem is reduced to a Cauchy singular integro-differential equation which can be numerically solved by using the Gauss-Chebyshev integration formula, the Chebyshev polynomials and the collocation method. Due to the presence of surface strain gradient elasticity on the crack faces, the stresses are bounded at the crack tips. The torsion problem of a circular cylinder containing two symmetric collinear radial cracks of equal length with surface strain gradient elasticity is also solved by using a similar method. Numerical results indicate that the surface strain gradient effect exerts a significant influence on the torsional rigidity and the jump in warping function. In particular, the jump in warping function forms a cusp shape with zero enclosed angle at the crack tips.

  4. Investigating Fracture Behaviors of Polymer and Polymeric Composite Materials Using Spiral Notch Torsion Test

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Jy-An John [ORNL; Ren, Fei [ORNL; Tan, Ting [ORNL; Lara-Curzio, Edgar [ORNL; Agastra, Pancasatya [Montana State University; Mandell, John [Montana State University; Bertelsen, Williams D. [Gougeon Brothers, Inc.; LaFrance, Carl M. [Molded Fiber Glass Companies

    2011-01-01

    Wind turbine blades are usually fabricated from fiber reinforced polymeric (FRP) materials, which are subject to complex loading conditions during service. The reliability of the blades thus depends on the mechanical behaviors of the FRP under various loading conditions. Specifically, the fracture behavior of FRP is of great importance to both the scientific research community and the wind industry. In the current project, a new testing technique is proposed based on the spiral notch torsion test (SNTT) to study the fracture behavior of composite structures under mixed mode loading conditions, particularly under combined Mode I (flexural or normal tensile stress) and Mode III (torsional shear stress) loading. For the SNTT test method, round-rod specimens with V-grooved spiral lines are subjected to pure torsion. Depending on the pitch angle of the spiral lines, pure Mode I, pure Mode III, or mixed Mode I/Mode III loading conditions can be simulated. A three dimensional finite element analysis is then used to evaluate the fracture toughness and energy release rate of SNTT specimens. In the current study, both epoxy and fiberglass reinforced epoxy materials are investigated using the SNTT technique. This paper will discuss the fracture behaviors of mode I and mixed mode samples, with or without fatigue precrack. In addition, results from fractographic study and finite element analysis will be presented and discussed in detail.

  5. Association of Torsion With Testicular Cancer: A Retrospective Study.

    Science.gov (United States)

    Uguz, Sami; Yilmaz, Sercan; Guragac, Ali; Topuz, Bahadır; Aydur, Emin

    2016-02-01

    Testicular torsion is a medical emergency that usually requires surgical exploration. However, testicular malignancy has been anecdotally reported with the association of torsion in surgical specimens, and the published data remain scant on the association of torsion with testicular tumors. By retrospective medical record review, we identified 32 patients who had been diagnosed with testicular torsion, 20 of whom had undergone orchiectomy. Of these 20 patients, 2 were diagnosed with a malignancy. Our study, the largest case series to date, has shown an association between testicular torsion and testicular cancer of 6.4%. Testicular torsion is a medical emergency that usually requires surgical exploration. However, testicular malignancy has been anecdotally reported in association with torsion in surgical specimens. However, the published data remain scant on the association between torsion and the presence of testicular tumors. The present retrospective study explored the association between torsion and testicular cancer in patients with testicular torsion undergoing orchiectomy during scrotal exploration. A medical record review was performed of patients who had had a diagnosis of testicular torsion from January 2003 to February 2015. The clinicopathologic characteristics of the patients were recorded. A total of 32 patients were identified. Their mean age was 21.1 years (range, 7-39 years). All the patients had unilateral testicular torsion, which affected the left side in 17 and the right side in 15. Manual detorsion was successful in 6 patients, and 26 patients underwent emergency surgery with testicular detorsion (6 fixation surgery and 20 orchiectomy). The type of incision was scrotal in 6, inguinal in 10, and unspecified in 4. Pathologic examination of the orchiectomy specimens showed malignancy in 2 cases (seminoma and malign mixed germ cell tumor). To the best of our knowledge, the present single-center case series is the largest case series to date of

  6. Secondary Torsion of Vermiform Appendix with Mucinous Cystadenoma

    Directory of Open Access Journals (Sweden)

    Maki Kitagawa

    2007-06-01

    Full Text Available Torsion of the vermiform appendix is a rare disorder, which causes abdominal symptoms indistinguishable from acute appendicitis. We report a case (a 34-year-old male of secondary torsion of the vermiform appendix with mucinous cystadenoma. This case was characterized by mild inflammatory responses, pentazocine-resistant abdominal pain, and appendiceal tumor, which was not enhanced by the contrast medium on computed tomography presumably because of reduced blood flow by the torsion. These findings may be helpful for the preoperative diagnosis of secondary appendiceal torsion.

  7. Quantifying Mapping Orbit Performance in the Vicinity of Primitive Bodies

    Science.gov (United States)

    Pavlak, Thomas A.; Broschart, Stephen B.; Lantoine, Gregory

    2015-01-01

    Predicting and quantifying the capability of mapping orbits in the vicinity of primitive bodies is challenging given the complex orbit geometries that exist and the irregular shape of the bodies themselves. This paper employs various quantitative metrics to characterize the performance and relative effectiveness of various types of mapping orbits including terminator, quasi-terminator, hovering, ping pong, and conic-like trajectories. Metrics of interest include surface area coverage, lighting conditions, and the variety of viewing angles achieved. The metrics discussed in this investigation are intended to enable mission designers and project stakeholders to better characterize candidate mapping orbits during preliminary mission formulation activities. The goal of this investigation is to understand the trade space associated with carrying out remote sensing campaigns at small primitive bodies in the context of a robotic space mission. Specifically, this study seeks to understand the surface viewing geometries, ranges, etc. that are available from several commonly proposed mapping orbits architectures

  8. Cyclic and Torsional Fatigue Resistance of Reciprocating Single Files Manufactured by Different Nickel-titanium Alloys.

    Science.gov (United States)

    Alcalde, Murilo P; Tanomaru-Filho, Mario; Bramante, Clovis M; Duarte, Marco Antonio H; Guerreiro-Tanomaru, Juliane Maria; Camilo-Pinto, Jader; Só, Marcus Vinicius Reis; Vivan, Rodrigo Ricci

    2017-07-01

    The aim of this study was to evaluate the cyclic and torsional fatigue resistance of the following reciprocating single-file systems: ProDesign R 25.06 (Easy Equipamentos Odontológicos, Belo Horizonte, Brazil), Reciproc R25 (VDW GmbH, Munich, Germany), and Unicone L25 (Medin SA, Nové Město in Moravě, Czech Republic). Sixty instruments of the ProDesign R, Reciproc R25, and Unicone L25 systems (n = 20) were used. Cyclic fatigue resistance was tested measuring the time to failure in an artificial stainless steel canal with a 60° angle and a 5-mm radius of curvature (n = 10). Torque and angle of rotation at failure of new instruments (n = 10) in the 3 mm from the tip portion were measured during torsional testing according to ISO 3630-1. The fractured surface of each fragment was examined by scanning electron microscopy. Data were analyzed using 1-way analysis of variance and Tukey tests, and the level of significance was set at 5%. The cyclic fatigue resistance values of ProDesign R 25.06 were significantly higher than the other groups (P < .05). Reciproc R25 showed higher fatigue resistance than Unicone L25 (P < .05). In relation to the torsional test, the ProDesign R 25.06 and Unicone L25 systems showed higher angular rotation until fracture than Reciproc R25 (P < .05). However, Reciproc R25 and Unicone L25 showed higher torque load than ProDesign R 25.06 (P < .05). Scanning electron microscopic analysis showed similar and typical features of cyclic and torsional failure for all instruments tested. ProDesign R presented the highest cyclic fatigue resistance and angular rotation to failure compared with Reciproc and Unicone. However, Reciproc showed higher torsional strength to failure. Copyright © 2017 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  9. Nonlinear nonuniform torsional vibrations of bars by the boundary element method

    Science.gov (United States)

    Sapountzakis, E. J.; Tsipiras, V. J.

    2010-05-01

    In this paper a boundary element method is developed for the nonuniform torsional vibration problem of bars of arbitrary doubly symmetric constant cross-section taking into account the effect of geometrical nonlinearity. The bar is subjected to arbitrarily distributed or concentrated conservative dynamic twisting and warping moments along its length, while its edges are supported by the most general torsional boundary conditions. The transverse displacement components are expressed so as to be valid for large twisting rotations (finite displacement-small strain theory), thus the arising governing differential equations and boundary conditions are in general nonlinear. The resulting coupling effect between twisting and axial displacement components is considered and torsional vibration analysis is performed in both the torsional pre- or post-buckled state. A distributed mass model system is employed, taking into account the warping, rotatory and axial inertia, leading to the formulation of a coupled nonlinear initial boundary value problem with respect to the variable along the bar angle of twist and to an "average" axial displacement of the cross-section of the bar. The numerical solution of the aforementioned initial boundary value problem is performed using the analog equation method, a BEM based method, leading to a system of nonlinear differential-algebraic equations (DAE), which is solved using an efficient time discretization scheme. Additionally, for the free vibrations case, a nonlinear generalized eigenvalue problem is formulated with respect to the fundamental mode shape at the points of reversal of motion after ignoring the axial inertia to verify the accuracy of the proposed method. The problem is solved using the direct iteration technique (DIT), with a geometrically linear fundamental mode shape as a starting vector. The validity of negligible axial inertia assumption is examined for the problem at hand.

  10. Torsional Failure of Carbon Fiber Composite Plates Versus Stainless Steel Plates for Comminuted Distal Fibula Fractures.

    Science.gov (United States)

    Wilson, William K; Morris, Randal P; Ward, Adam J; Carayannopoulos, Nikoletta L; Panchbhavi, Vinod K

    2016-05-01

    Carbon fiber composite implants are gaining popularity in orthopedics, but with few independent studies of their failure characteristics under supra-physiologic loads. The objective of this cadaveric study was to compare torsional failure properties of bridge plating a comminuted distal fibula fracture with carbon fiber polyetheretherketone (PEEK) composite and stainless steel one-third tubular plates. Comminuted fractures were simulated in 12 matched pairs of fresh-frozen human fibulas with 2-mm osteotomies located 3 cm proximal to the tibiotalar joint. Each fibula pair was randomized for fixation and implanted with carbon fiber and stainless steel 5-hole one-third tubular plates. The constructs were loaded in external rotation at a rate of 1-degree/sec until failure with a materials testing system. Torsional stiffness and mode of failure, as well as displacement, torque, and energy absorption for the first instance of failure and peak failure, were determined. Statistical analysis was performed with paired t tests and chi-square. There were no significant differences among the 12 pairs for torsional stiffness, first failure torque, peak failure displacement, peak failure torque, or peak failure energy. Stainless steel plates exhibited significantly higher displacement (P steel plates permanently deformed significantly more often than the carbon fiber plates (P = .035). Carbon fiber plates exhibited no plastic deformation with delamination of the composite, and brittle catastrophic failure in 1 specimen. In a comminuted human fibula fracture fixation model, carbon fiber implants exhibited multiple pre-peak failures at significantly lower angles than the first failure for the stainless steel implants, with some delamination of composite layers and brittle catastrophic failure rather than plastic deformation. The torsional failure properties of carbon fiber composite one-third tubular plates determined in this independent study provide novel in vitro data for this

  11. Microstructure characterization of Cu processed by compression with oscillatory torsion

    Energy Technology Data Exchange (ETDEWEB)

    Rodak, K., E-mail: kinga.rodak@polsl.pl [Institute of Materials Science, Silesian University of Technology, Krasińskiego 8, 40-019 Katowice (Poland); Pawlicki, J., E-mail: jacek.pawlicki@polsl.pl [Department of Automotive Vehicle Construction, Silesian University of Technology, Krasińskiego 8, 40–019 Katowice (Poland)

    2014-08-15

    High purity Cu (99.9%) was subjected to severe plastic deformation up to a total effective strain ε{sub ft} = 130 through compression with the oscillatory torsion method at room temperature. This method produces an ultrafine grain microstructure. The microstructure evolution was investigated with respect to the value of the total effective strain using a scanning electron microscope with an electron-backscattered diffraction technique and a scanning transmission electron microscope. The results of the structural analyses show that increasing ε{sub ft} from 2 to 50 causes progress in the grain refinement. A quantitative study of the microstructure parameters, such as fraction of high angle boundaries, grain and subgrain diameter, and the area fraction of grains up to 1 μm, shows that deformation at ε{sub ft} = 45 guaranteed the best conditions for refining the microstructure of Cu. Using high values of ε{sub ft} in the range 60 to 130 restricts grain refinement because intensive recovery begins to dominate in the microstructure. - Highlights: • Cu was processed by SPD metodto an effective strain 130. • The microstructure evolution has been investigated. • The method allows to produce an ultrafine grain microstructure.

  12. Observation of Intralaminar Cracking in the Edge Crack Torsion Specimen

    Science.gov (United States)

    Czabaj, Michael W.; Ratcliffe, James G.; Davidson, Barry D.

    2013-01-01

    The edge crack torsion (ECT) test is evaluated to determine its suitability for measuring fracture toughness associated with mode III delamination growth onset. A series of ECT specimens with preimplanted inserts with different lengths is tested and examined using nondestructive and destructive techniques. Ultrasonic inspection of all tested specimens reveals that delamination growth occurs at one interface ply beneath the intended midplane interface. Sectioning and optical microscopy suggest that the observed delamination growth results from coalescence of angled intralaminar matrix cracks that form and extend across the midplane plies. The relative orientation of these cracks is approximately 45 deg with respect to the midplane, suggesting their formation is caused by resolved principal tensile stresses arising due to the global mode-III shear loading. Examination of ECT specimens tested to loads below the level corresponding to delamination growth onset reveals that initiation of intralaminar cracking approximately coincides with the onset of nonlinearity in the specimen's force-displacement response. The existence of intralaminar cracking prior to delamination growth onset and the resulting delamination extension at an unintended interface render the ECT test, in its current form, unsuitable for characterization of mode III delamination growth onset. The broader implications of the mechanisms observed in this study are also discussed with respect to the current understanding of shear-driven delamination in tape-laminate composites.

  13. Comparative analysis of torsional and bending behavior through finite-element models of 5 Ni-Ti endodontic instruments.

    Science.gov (United States)

    Arbab-Chirani, Reza; Chevalier, Valérie; Arbab-Chirani, Shabnam; Calloch, Sylvain

    2011-01-01

    The objectives of this study were to compare numerically the bending and torsional mechanical behavior of 5 endodontic rotary Ni-Ti instruments with equivalent size and various designs for tapers, pitch, and cutting blades.First, the geometries of Hero (20/0.06), HeroShaper (20/0.06), ProFile (20/0.06), Mtwo (20/0.06), and ProTaper F1 were generated by finite element code. Then, the 2 most representative clinical loadings, i.e., bending and torsion, were studied with an ad hoc model for the superelasticity of Ni-Ti. Bending was generated by tip deflection and torsion by a constant twist-angle of the tip. Mechanical behavior of these 5 endodontic rotary Ni-Ti instruments could be evaluated and compared. Protaper F1 presented the greatest level of bending stress and torque. Hero and HeroShaper were more rigid than ProFile and Mtwo. This numerical comparison evaluated the effects of the geometrical parameters on the instrumental mechanical behavior. The 5 endodontic instruments, investigated in the present study, do not have the same bending and torsional mechanical behavior. Each clinician must be aware of these behavior differences so as to use the adequate file according to the clinical situation and to the manufacturer's recommendations. Copyright © 2011 Mosby, Inc. All rights reserved.

  14. Toward laboratory torsional spine magnetic reconnection

    Science.gov (United States)

    Chesny, David L.; Orange, N. Brice; Oluseyi, Hakeem M.; Valletta, David R.

    2017-12-01

    Magnetic reconnection is a fundamental energy conversion mechanism in nature. Major attempts to study this process in controlled settings on Earth have largely been limited to reproducing approximately two-dimensional (2-D) reconnection dynamics. Other experiments describing reconnection near three-dimensional null points are non-driven, and do not induce any of the 3-D modes of spine fan, torsional fan or torsional spine reconnection. In order to study these important 3-D modes observed in astrophysical plasmas (e.g. the solar atmosphere), laboratory set-ups must be designed to induce driven reconnection about an isolated magnetic null point. As such, we consider the limited range of fundamental resistive magnetohydrodynamic (MHD) and kinetic parameters of dynamic laboratory plasmas that are necessary to induce the torsional spine reconnection (TSR) mode characterized by a driven rotational slippage of field lines - a feature that has yet to be achieved in operational laboratory magnetic reconnection experiments. Leveraging existing reconnection models, we show that within a 3$ apparatus, TSR can be achieved in dense plasma regimes ( 24~\\text{m}-3$ ) in magnetic fields of -1~\\text{T}$ . We find that MHD and kinetic parameters predict reconnection in thin current sheets on time scales of . While these plasma regimes may not explicitly replicate the plasma parameters of observed astrophysical phenomena, studying the dynamics of the TSR mode within achievable set-ups signifies an important step in understanding the fundamentals of driven 3-D magnetic reconnection and the self-organization of current sheets. Explicit control of this reconnection mode may have implications for understanding particle acceleration in astrophysical environments, and may even have practical applications to fields such as spacecraft propulsion.

  15. Heterogeneous flow during high-pressure torsion

    Directory of Open Access Journals (Sweden)

    Roberto B. Figueiredo

    2013-06-01

    Full Text Available High-Pressure Torsion (HPT has attracted significant attention in recent years as an effective technique to process ultrafine and nanostructured materials. The hydrostatic pressure developed during processing prevents the occurrence of cracks and the low thickness to diameter ratio provides the opportunity for developing high strains at low numbers of rotations. The present work analyses the plastic flow during HPT. Experimental results and computer modeling are used to describe heterogeneous plastic flow. It is shown that variations in structure, hardness and in the distribution of strain are observed along the disc thickness. The sources of these heterogeneities are discussed.

  16. Adnexal torsion in third trimester of pregnancy

    Science.gov (United States)

    Passarinho, Rita Marquez; Afonso, Énio; Reis, Luís; Santos Silva, Isabel

    2012-01-01

    The authors report an unusual case of adnexal torsion in a patient in the third trimester of pregnancy. A 32-year-old woman, gravida 1, para 0, in the 32nd week of gestation initially presented with clinical signs of acute appendicitis. On laparotomy, it was identified that a necrotic mass of the right adnexa and performed a unilateral salpingo-oophorectomy. The postoperative period was uneventful. In the 37th week of gestation, the labour was induced by fetal intrauterine growth restriction. She delivered vaginally, a healthy baby, with 2085 g and an Apgar score of 9 and 10 at the first and fifth minute, respectively. PMID:23109412

  17. A Patient Presenting with Concurrent Testis Torsion and Epididymal Leiomyoma

    Directory of Open Access Journals (Sweden)

    E. Arpali

    2013-01-01

    Full Text Available Leiomyomas are the second most common tumors of epididymis. Patients with leiomyomas are sometimes misdiagnosed with testicular tumors. A Case of a patient with a scrotal mass presenting with testicular torsion is reported. Concurrent occurrence of testicular torsion and epididymal leiomyoma is an extremely rare condition.

  18. CONSTRAINING SPACETIME TORSION WITH THE MOON, MERCURY AND LAGEOS

    Directory of Open Access Journals (Sweden)

    Riccardo March

    2013-12-01

    Full Text Available We consider an extension of Einstein General Relativity where, beside the Riemann curvature tensor, we suppose the presence of a torsion tensor. Using a parametrized theory based on symmetry arguments, we report on some results concerning the constraints that can be put on torsion parameters by studying the orbits of a test body in the solar system.

  19. Correlation of severity of penile torsion with type of hypospadias ...

    African Journals Online (AJOL)

    A. Bhat

    Abstract. Objective: This study was carried out to evaluate the correlation between the severity of penile torsion on the one hand and the degree of ventral penile curvature and the type of hypospadias on the other. We also assessed the effectiveness of correction of chordee and torsion by penile degloving and mobilization ...

  20. Mechanical origins of rightward torsion in early chick brain development

    Science.gov (United States)

    Chen, Zi; Guo, Qiaohang; Dai, Eric; Taber, Larry

    2015-03-01

    During early development, the neural tube of the chick embryo undergoes a combination of progressive ventral bending and rightward torsion. This torsional deformation is one of the major organ-level left-right asymmetry events in development. Previous studies suggested that bending is mainly due to differential growth, however, the mechanism for torsion remains poorly understood. Since the heart almost always loops rightwards that the brain twists, researchers have speculated that heart looping affects the direction of brain torsion. However, direct evidence is lacking, nor is the mechanical origin of such torsion understood. In our study, experimental perturbations show that the bending and torsional deformations in the brain are coupled and that the vitelline membrane applies an external load necessary for torsion to occur. Moreover, the asymmetry of the looping heart gives rise to the chirality of the twisted brain. A computational model and a 3D printed physical model are employed to help interpret these findings. Our work clarifies the mechanical origins of brain torsion and the associated left-right asymmetry, and further reveals that the asymmetric development in one organ can induce the asymmetry of another developing organ through mechanics, reminiscent of D'Arcy Thompson's view of biological form as ``diagram of forces''. Z.C. is supported by the Society in Science - Branco Weiss fellowship, administered by ETH Zurich. L.A.T acknowledges the support from NIH Grants R01 GM075200 and R01 NS070918.

  1. experimental and analytical comparison of torsion, bending moment

    African Journals Online (AJOL)

    HOD

    from the beam's principal axis at the mid-span, using. Computerized Universal Testing Machine TUE-C-100. BS 8110, Euro code 2 and ACI 318 were used to calculate the ... Less attention was paid in the past by reinforced concrete designers to these effects of torsion in reinforced concrete members. When torsion is.

  2. Quantum gravity effect in torsion driven inflation and CP violation

    Energy Technology Data Exchange (ETDEWEB)

    Choudhury, Sayantan [Department of Theoretical Physics, Tata Institute of Fundamental Research,Colaba, 1, Homi Bhabha Road, Mumbai 400005 (India); Pal, Barun Kumar [Inter-University Centre for Astronomy and Astrophysics,Ganeshkhind, Pune 411007 (India); Netaji Nagar College for Women,Regent Estate, Kolkata 700092 (India); Basu, Banasri; Bandyopadhyay, Pratul [Physics and Applied Mathematics Unit, Indian Statistical Institute,203 B.T. Road, Kolkata 700 108 (India)

    2015-10-28

    We have derived an effective potential for inflationary scenario from torsion and quantum gravity correction in terms of the scalar field hidden in torsion. A strict bound on the CP violating θ parameter, O(10{sup −10})<θ

  3. Lingular segment torsion following a left upper division segmentectomy.

    Science.gov (United States)

    Taira, Naohiro; Kawasaki, Hidenori; Takahara, Sayako; Furugen, Tomonori; Ichi, Takaharu; Kushi, Kazuaki; Yohena, Tomofumi; Kawabata, Tsutomu

    2017-01-01

    Numerous publications regarding lung torsion have reported lobar torsion after lobectomy. On the other hand, torsion of the remaining segment after segmentectomy is extremely rare. We herein report a rare case of lingular segment torsion following a left upper division segmentectomy. A 68-year old female underwent thoracoscopic segmentectomy of the left upper division. She underwent chest radiography immediately after the initial surgery, which revealed complete expansion on the operated side. Routine chest radiograph findings on postoperative day 1 demonstrated atelectasis on the operated side, although she did not have any symptoms. Chest computed tomography was conducted because a follow-up chest radiograph on postoperative day 5 showed no improvement, and she was diagnosed with torsion of the lingular segment. We performed an exploratory thoracotomy. Based on intraoperative findings, the lingular segment was found to have a 90° clockwise torsion along the pedicle axis, although the segment was viable. We straightened the kinked lingular segment and affixed the lingular segment to the left lower lobe. The postoperative course was uneventful. Although lobectomy is the most common cause of lung torsion, physicians should check for lung segment torsion when performing segmentectomy. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

  4. Correlation of severity of penile torsion with type of hypospadias ...

    African Journals Online (AJOL)

    Objective: This study was carried out to evaluate the correlation between the severity of penile torsion on the one hand and the degree of ventral penile curvature and the type of hypospadias on the other. We also assessed the effectiveness of correction of chordee and torsion by penile degloving and mobilization of the ...

  5. Primary omental torsion in children: case report | Khalid | Pan ...

    African Journals Online (AJOL)

    Primary omental torsion is a rare cause of acute abdominal pain, we report a case of 10-year-old boy admitted with crampy abdominal pain, routine laboratory tests and plain abdominal radiography was normal, the patient underwent surgical exploration with the initial diagnosis of appendicitis, primary omental torsion was ...

  6. Case series on testicular torsion: an educational emergency for sub ...

    African Journals Online (AJOL)

    305 records ... Testicular torsion remains a common surgical emergency of adolescent males presenting with sudden onset of intense scrotal pain in Africa. While the magnitude of testicular torsion is not known it has been identified as a cause of male infertility. Testicular loss in Africa is directly related to delay in surgery and ...

  7. Dismal salvage of testicular torsion: A call to action! | Maranya ...

    African Journals Online (AJOL)

    Background: Testicular ischaemia and infarction in cases of torsion depend on the duration and degree of twisting. Early evaluation and treatment are associated with high salvage reports. Objective: To determine the salvage rates of testicular torsion in selected hospitals at the Coast Province of Kenya Design: A ...

  8. Intermittent Testicular Torsion | Obi | Nigerian Journal of Clinical ...

    African Journals Online (AJOL)

    Objective: The aim of this study is to highlight the clinical characteristics of patients with intermittent testicular torsion and draw attention to this underreported condition. Methods: Clinical and demographic data of all patients treated for intermittent testicular torsion from January 2007 to June 2015 were prospectively collected ...

  9. Torsion of the Spermatic Cord: Is Bilateral Orchidopexy Really ...

    African Journals Online (AJOL)

    Aim: To evaluate the rationale for bilateral orchidopexy as treatment for unilateral torsion of the testis, by determining how frequently the contralateral testis shows an abnormal pathology in unilateral testicular torsion. Patients and Methods:This is a retrospective study using adult urology patients treated for both acute and ...

  10. Manual Detorsion of Testicular Torsion - A Primary Care Intervention ...

    African Journals Online (AJOL)

    Testicular torsion is one of the known acute urological emergencies that require prompt intervention. Salvage of the testis is only possible if derotation is performed within 6 hours of onset of symptoms. The objective of this paper is to report successful manual detorsion of the testes of patients with testicular torsion.

  11. Prediction of Torsional Strength for Very High Early Strength Geopolymer

    Directory of Open Access Journals (Sweden)

    Woraphot PRACHASAREE

    2017-11-01

    Full Text Available Very early high strength geopolymers are gaining acceptance as alternative repair materials for highways and other infrastructure. In this study, a very rapid geopolymer binder based on Metakaolin (MK and Parawood ash (PWA, developed by the authors, was experimentally tested and a prediction model for its torsional strength is proposed. The geopolymer samples were subjected to uniaxial compression, flexural beam, and torsion tests. The modulus of rupture and torsional strength in terms of compression strength were found to be well approximated by 0.7(f’c1/2 and 1/7(x2y (f’c1/2, respectively. Also an interaction relation to describe combined bending and torsion was developed in this study. In addition, the effects of aspect ratio (y/x were studied on both torsional strength and combined bending and torsion. It was found that an aspect ratio of y/x = 3 significantly reduced the torsional resistance, to about 50 % of the torsional strength of a square section.DOI: http://dx.doi.org/10.5755/j01.ms.23.4.17280

  12. Effects of toughness anisotropy and combined tension, torsion, and bending loads on fracture behavior of ferritic nuclear pipe

    Energy Technology Data Exchange (ETDEWEB)

    Mohan, R.; Marshall, C.; Ghadiali, N.; Wilkowski, G. [Battelle, Columbus, OH (United States)

    1997-04-01

    This paper summarizes work on angled through-wall-crack initiation and combined loading effects on ferritic nuclear pipe performed as part of the Nuclear Regulatory Commission`s research program entitled {open_quotes}Short Cracks In Piping an Piping Welds{close_quotes}. The reader is referred to Reference 1 for details of the experiments and analyses conducted as part of this program. The major impetus for this work stemmed from the observation that initially circumferentially oriented cracks in carbon steel pipes exhibited a high tendency to grow at a different angle when the cracked pipes were subjected to bending or bending plus pressure loads. This failure mode was little understood, and the effect of angled crack grown from an initially circumferential crack raised questions about how cracks in a piping system subjected to combined loading with torsional stresses would behave. There were three major efforts undertaken in this study. The first involved a literature review to assess the causes of toughness anisotropy in ferritic pipes and to develop strength and toughness data as a function of angle from the circumferential plane. The second effort was an attempt to develop a screening criterion based on toughness anisotropy and to compare this screening criterion with experimental pipe fracture data. The third and more significant effort involved finite element analyses to examine why cracks grow at an angle and what is the effect of combined loads with torsional stresses on a circumferentially cracked pipe. These three efforts are summarized.

  13. Peculiar torsion dynamical response of spider dragline silk

    Science.gov (United States)

    Liu, Dabiao; Yu, Longteng; He, Yuming; Peng, Kai; Liu, Jie; Guan, Juan; Dunstan, D. J.

    2017-07-01

    The torsional properties of spider dragline silks from Nephila edulis and Nephila pilipes spiders are investigated by using a torsion pendulum technique. A permanent torsional deformation is observed after even small torsional strain. This behaviour is quite different from that of the other materials tested here, i.e., carbon fiber, thin metallic wires, Kevlar fiber, and human hair. The spider dragline thus displays a strong energy dissipation upon the initial excitation (around 75% for small strains and more for a larger strain), which correspondingly reduces the amplitude of subsequent oscillations around the new equilibrium position. The variation of torsional stiffness in relaxation dynamics of spider draglines for different excitations is also determined. The experimental result is interpreted in the light of the hierarchical structure of dragline silk.

  14. Krukenberg Tumor: A Rare Cause of Ovarian Torsion

    Directory of Open Access Journals (Sweden)

    Sameer Sandhu

    2012-01-01

    Full Text Available Ovarian torsion is the fifth most common gynecological surgical emergency. Ovarian torsion is usually associated with a cyst or a tumor, which is typically benign. The most common is mature cystic teratoma. We report the case of a 43-year-old woman who came to the Emergency Department with rare acute presentation of bilateral Krukenberg tumors, due to unilateral ovarian torsion. In this case report, we highlight the specific computed tomography (CT features of ovarian torsion and demonstrate the unique radiological findings on CT imaging. Metastasis to the ovary is not rare and 5 to 10% of all ovarian malignancies are metastatic. The stomach is the common primary site in most Krukenberg tumors (70%; an acute presentation of metastatic Krukenberg tumors with ovarian torsion is rare and not previously reported in radiology literature.

  15. Lung lobe torsion in seven juvenile dogs.

    Science.gov (United States)

    Latimer, Christian R; Lux, Cassie N; Sutton, Jessie S; Culp, William T N

    2017-12-15

    CASE DESCRIPTION 7 juvenile (< 12 months old) dogs with lung lobe torsion were evaluated. CLINICAL FINDINGS All patients were male; breeds included Pug (n = 5), Chinese Shar-Pei (1), and Bullmastiff (1). Dyspnea and lethargy were the most common initial complaints, with a duration of clinical signs ranging from 1 to 10 days. A CBC showed leukocytosis and neutrophilia in all dogs. Anemia was present in 6 dogs, 2 of which received packed RBC transfusions. The diagnosis was made on the basis of results of thoracic radiography, CT, ultrasonography, or a combination of modalities. The left cranial lung lobe was most commonly affected (n = 4), followed by the right middle lung lobe (2) and the right cranial lung lobe (1). TREATMENT AND OUTCOME A lateral intercostal thoracotomy with lobectomy of the affected lobe was performed in all patients. All dogs survived to be discharged between 1 and 2 days postoperatively. Six of 7 owners contacted for follow-up information 7 to 170 months after discharge reported satisfaction with the treatment and no apparent signs of recurrence of disease. CLINICAL RELEVANCE The juvenile patients of this report were successfully treated surgically with no apparent complications. Clinicians should be aware of the possibility of lung lobe torsion when evaluating young dogs with clinical signs related to the respiratory system, including those with vague signs, to avoid undue delays in treatment.

  16. Analytical approach to calculate bending, longitudinal and torsional local stiffness of an asymmetric circumferential crack with contact condition

    Science.gov (United States)

    Sharafi, Mojtaba Meidan; Nikravesh, Majid Yadavar; Safarpour, Pedram

    2017-09-01

    In this paper, bending, longitudinal and torsional stiffness of an eccentric circumferential crack is investigated with taking into account contact condition on the crack surfaces based on fracture mechanics. Although several researches have analyzed stress intensity factors of symmetric circumferential crack, the stiffness of an asymmetric circumferential crack in different directions (along and perpendicular to eccentricity) regarding contact condition has not been studied by an analytical method until now. In this paper we aim to describe behavior of eccentric circumferential crack under axial loading and establish a relation between axial force and the resulting displacement vector. The twisting angle of asymmetric circumferential crack due to torsional loading is also calculated and compared to twisting angle of a symmetric crack. In order to simulate the local bending stiffness in the contact condition, nonlinear governing equations of bending stiffness associated to cracked beam section is developed by dividing it to strip elements and utilizing stiffness equations related to noncontact condition. It is validated by 3D finite element (FE) nonlinear model. Results show a significant compatibility between presented analytical and 3D FE methods. Moreover results of simulations show that without taking into account contact condition, axial, torsional and bending stiffness of symmetric and asymmetric circumferential crack are equal and radius of un-cracked area is the only influential factor.

  17. Torsion Des Courbes Elliptiques Sur Les Corps Cubiques. (torsion Of Elliptic Curves Over Cubic Fields)

    CERN Document Server

    Parent, P

    2000-01-01

    Given a number field $K$ and an elliptic curve $E$ defined over $K$, there exists only finitely many torsion points in $E(K)$; this is the theorem of L. Merel in [Zbl 936.11037]. How is the torsion subgroup of $E(K)$ made? Let $d$ be a positive integer, let $S(d)$ be the set of all the prime numbers $p$ such that there exists a number field $K$ of degree $d$ over ${\\Bbb Q}$ and an elliptic curve $E$ defined over $K$ with a rational point of order $p$, not equal to the origin of $E$. The set $S(d)$ is finite, and $S(1)=\\{2,3,5,7\\}$ (B. Mazur [Zbl 394.14008]), $S(2)=\\{2,3,5,7,11,13\\}$ (S. Kamienny [Zbl 832.14023]). More generally if $p\\in S(d)$ then $p\\leq(1+3^{d/2})^2$ if $d\

  18. Online Identification and Verification of the Elastic Coupling Torsional Stiffness

    Directory of Open Access Journals (Sweden)

    Wanyou Li

    2016-01-01

    Full Text Available To analyze the torsional vibration of a diesel engine shaft, the torsional stiffness of the flexible coupling is a key kinetic parameter. Since the material properties of the elastic element of the coupling might change after a long-time operation due to the severe working environment or improper use and the variation of such properties will change dynamic feature of the coupling, it will cause a relative large calculation error of torsional vibration to the shaft system. Moreover, the torsional stiffness of the elastic coupling is difficult to be determined, and it is inappropriate to measure this parameter by disassembling the power unit while it is under normal operation. To solve these problems, this paper comes up with a method which combines the torsional vibration test with the calculation of the diesel shafting and uses the inherent characteristics of shaft torsional vibration to identify the dynamic stiffness of the elastic coupling without disassembling the unit. Analysis results show that it is reasonable and feasible to identify the elastic coupling dynamic torsional stiffness with this method and the identified stiffness is accurate. Besides, this method provides a convenient and practical approach to examine the dynamic behavior of the long running elastic coupling.

  19. Experimental investigation of torsional vibration isolation using Magneto Rheological Elastomer

    Directory of Open Access Journals (Sweden)

    Praveen Shenoy K

    2018-01-01

    Full Text Available Rotating systems suffer from lateral and torsional vibrations which have detrimental effect on the roto-dynamic performance. Many available technologies such as vibration isolators and vibration absorbers deal with the torsional vibrations to a certain extent, however passive isolators and absorbers find less application when the input conditions are dynamic. The present work discusses use of a smart material called as Magneto Rheological Elastomer (MRE, whose properties can be changed based on magnetic field input, as a potential isolator for torsional vibrations under dynamic loading conditions. Carbonyl Iron Particles (CIP of average size 5 μm were mixed with RTV Silicone rubber to form the MRE. The effect of magnetic field on the system parameters was comprehended under impulse loading conditions using a custom built in-house system. Series arrangement of accelerometers were used to differentiate between the torsional and the bending modes of vibration of the system. Impact hammer tests were carried out on the torsional system to study its response, in the presence and absence of magnetic field. The tests revealed a shift in torsional frequency in the presence of magnetic field which elucidates the ability of MRE to work as a potential vibration isolator for torsional systems.

  20. Uterine torsion in a Sprague Dawley rat (Rattus norvegicus

    Directory of Open Access Journals (Sweden)

    K. H. Erlwanger

    2011-04-01

    Full Text Available Uterine torsion is a twisting of the uterus or uterine horn perpendicular to its long axis.We report a case of uterine torsion in an adult breeding Sprague Dawley rat. The rat died a month after her last recorded delivery. Post mortem examination of the rat revealed 270° torsion of the right uterine horn. The uterus contained a single foetus. The liver was pale and enlarged. The rest of the viscera appeared normal. Histopathological examination showed acute hepatic necrosis and pulmonary congestion with mild lymphocytic infiltrates peribronchially. The acute hepatic necrosis may have been associated with septicaemia due to compromised blood vessels following the uterine torsion. The presence of a single foetus could have resulted in foeto-maternal disproportion with resultant uterine torsion. Torsion of the uterus can be accompanied by haemostatic and metabolic complications, which could have caused the death of the rat. Although uterine torsion is a rare condition in rats, it should be considered as a potential complication of gestation in animal breeding units.

  1. Cyclic fatigue and torsional strength of three different thermally treated reciprocating nickel-titanium instruments.

    Science.gov (United States)

    Alcalde, Murilo Priori; Duarte, Marco Antonio Hungaro; Bramante, Clovis Monteiro; de Vasconselos, Bruno Carvalho; Tanomaru-Filho, Mario; Guerreiro-Tanomaru, Juliane Maria; Pinto, Jader Camilo; Só, Marcus Vinicius Reis; Vivan, Rodrigo Ricci

    2017-12-09

    The aim of this study was to evaluate the cyclic and torsional fatigue resistance of the reciprocating single-file systems Reciproc Blue 25.08 (VDW GmbH, Munich, Germany), Prodesign R 25.06 (Easy Dental Equipment, Belo Horizonte, Brazil), and WaveOne Gold 25.07 (Dentsply/Tulsa Dental Specialties, Tulsa, OK, USA). Sixty reciprocating instruments of the systems Reciproc Blue R25 (RB #25 .08 taper), Prodesign R (PDR #25 .06 taper), and WaveOne Gold (WOG #25 .07 taper) (n = 20) were used. Cyclic fatigue resistance testing was performed by measuring the time to failure in an artificial stainless steel canal with a 60° angle of curvature and a 5-mm radius located 5 mm from the tip (n = 10). The torsional test (ISO 3630-1) evaluated the torque and angle of rotation at failure of new instruments (n = 10) in the portion 3 mm from the tip. The fractured surface of each fragment was also observed using scanning electron microscopy (SEM). In addition, a supplementary examination was performed to measure the cross-sectional area of each instrument 3 and 5 mm from the tip. The data were analyzed using one-way ANOVA and Tukey's test, and the level of significance was set at 5%. The cyclic fatigue resistance values of PDR 25.06 were significantly higher (P  0.05). PDR 25.06 showed higher angular rotation values than RB 25.08 and WOG 25.07 (P < 0.05). RB 25.08 presented higher angular rotation than WOG 25.07 (P < 0.05). The cross-sectional area analysis showed that PDR 25.06 presented the smallest cross-sectional areas at 3 and 5 mm from the tip (P < 0.05). PDR 25.06 presented the highest cyclic fatigue resistance and angular rotation until fracture compared to RB 25.08 and WOG 25.07. In addition, RB 25.08 and WOG 25.07 had higher torsional strength than PDR 25.06. In endodontic practice, thermally treated reciprocating instruments have been used for the root canal preparation of curved and constricted canals; therefore, these instruments should

  2. Torsion based universal MEMS logic device

    KAUST Repository

    Ilyas, Saad

    2015-10-28

    In this work we demonstrate torsion based complementary MEMS logic device, which is capable, of performing INVERTER, AND, NAND, NOR, and OR gates using one physical structure within an operating range of 0-10 volts. It can also perform XOR and XNOR with one access inverter using the same structure with different electrical interconnects. The paper presents modeling, fabrication and experimental calculations of various performance features of the device including lifetime, power consumption and resonance frequency. The fabricated device is 535 μm by 150 μm with a gap of 1.92 μm and a resonant frequency of 6.51 kHz. The device is capable of performing the switching operation with a frequency of 1 kHz.

  3. A new method for tibial torsion measurement by computerized tomography.

    Science.gov (United States)

    Madadi, Firooz; Madadi, Firoozeh; Maleki, Arash; Shamie, Arya Nick; Washington, Eleby Rudolph; Yazdanshenas, Hamed

    2016-03-01

    Computerized tomography (CT) is the gold standard technique for tibial torsion assessment. This study compared two methods of tibial torsion assessment and proposed a new method, which could be of value in cases of abnormal fibular changes. The CT-scanograms of 60 participants were assessed by using two different techniques, differed in determination of the distal tibial axis. The interobserver reliability was 0.861 and 0.863 in the first and second methods, respectively. The intraobserver reliability in both measurement methods was 0.868. We proposed a reliable method, independent of the fibular midpoint, in assessment of tibial torsion by CT.

  4. The Torsional Eccentricity of the Structures in Miscellaneous Design Codes

    Directory of Open Access Journals (Sweden)

    Ioana Olteanu

    2010-03-01

    Full Text Available Structures rarely achieve structural symmetry. Even in symmetric structures, the asymmetric position of the structural components tends to produce an effective asymmetric structure. Such an asymmetry even if is small, can produce a torsional response coupled with translational response. In the torsional analysis, the provisions of the seismic norms are based on determining the static eccentricity. In this paper is presented a general way of computing the eccentricity in torsional design. The purpose of this article is to make a comparison of the general rules used to determine the eccentricity and their values. Are taken into account the norms from: Romania, Europe, Japan, Germany and the United States of America.

  5. Evaluation of the Cyclic Fatigue and Torsional Resistance of Novel Nickel-Titanium Rotary Files with Various Alloy Properties.

    Science.gov (United States)

    Kaval, Mehmet Emin; Capar, Ismail Davut; Ertas, Hüseyin

    2016-12-01

    The purpose of this study was to evaluate the cyclic fatigue and torsional resistance of Hyflex EDM, ProTaper Gold (PTG), and ProTaper Universal (PTU) instruments. For the cyclic fatigue test, 10 instruments from each group were tested by using a stainless steel block with 1.5-mm diameter and 3-mm radius of 60° angle of curvature. The instruments were allowed to rotate by using a low-torque motor, and number of cycles from the beginning to the fracture was recorded. Torsional resistance of the instruments (n = 10) was evaluated according to ISO 3630-1. The rotational speed of the instruments was set in the clockwise direction at 2 rpm. The maximum torque and angular deflection until fracture of the instrument were recorded. The data were analyzed by using one-way analysis of variance followed by post hoc Tukey test (P = .05). HyFlex EDM instruments exhibited the highest cyclic fatigue resistance and were followed by PTG and PTU groups, respectively. The mean fragment length for PTU instruments was significantly shorter than that for Hyflex EDM and PTG instruments. PTG instruments demonstrated significantly higher torsional resistance than HyFlex EDM files (P = .025), and the distortion angle of the instruments ranged as follows: PTU Hyflex EDM files. Hyflex EDM files demonstrated significantly higher cyclic fatigue resistance. Although PTG and PTU have similar cross-sectional design, PTG instruments presented higher cyclic fatigue and torsional resistance than PTU instruments. The enhanced alloy properties of PTG might be considered as the main reason for those differences. Copyright © 2016 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  6. Glaucoma, Open-Angle

    Science.gov (United States)

    ... USAJobs Home > Statistics and Data > Glaucoma, Open-angle Glaucoma, Open-angle Open-angle Glaucoma Defined In open-angle glaucoma, the fluid passes ... 2010 2010 U.S. Age-Specific Prevalence Rates for Glaucoma by Age and Race/Ethnicity The prevalence of ...

  7. Spin-torsion effects in the hyperfine structure of methanol

    Science.gov (United States)

    Coudert, L. H.; Gutlé, C.; Huet, T. R.; Grabow, J.-U.; Levshakov, S. A.

    2015-07-01

    The magnetic hyperfine structure of the non-rigid methanol molecule is investigated experimentally and theoretically. 12 hyperfine patterns are recorded using molecular beam microwave spectrometers. These patterns, along with previously recorded ones, are analyzed in an attempt to evidence the effects of the magnetic spin-torsion coupling due to the large amplitude internal rotation of the methyl group [J. E. M. Heuvel and A. Dymanus, J. Mol. Spectrosc. 47, 363 (1973)]. The theoretical approach setup to analyze the observed data accounts for this spin-torsion in addition to the familiar magnetic spin-rotation and spin-spin interactions. The theoretical approach relies on symmetry considerations to build a hyperfine coupling Hamiltonian and spin-rotation-torsion wavefunctions compatible with the Pauli exclusion principle. Although all experimental hyperfine patterns are not fully resolved, the line position analysis yields values for several parameters including one describing the spin-torsion coupling.

  8. Isolated adnexal torsion in a 20-week spontaneous twin pregnancy

    Directory of Open Access Journals (Sweden)

    Ilker Kahramanoglu

    2016-01-01

    Discussion: Adnexal torsion as a cause of acute abdomen may be kept in mind in pregnants, even if there is no predisposing factor. Laparoscopy may be performed safely in 2nd trimester for acute abdomen.

  9. Outcomes of Surgery for Posterior Polar Cataract Using Torsional Ultrasound

    Directory of Open Access Journals (Sweden)

    Selçuk Sızmaz

    2013-10-01

    Full Text Available Purpose: The aim of this study is to report outcomes of surgery for posterior polar cataract using torsional ultrasound. Material and Method: Medical records of 26 eyes of 21 consecutive patients with posterior polar cataract who had cataract surgery using the torsional phacoemulsification were evaluated retrospectively. The surgical procedure used, phacoemulsification parameters, intraoperative complications, and postoperative visual outcome were recorded. Results: Of the 26 eyes, 24 (92.3% had small to medium posterior polar opacity. Two eyes had large opacity. All surgeries were performed using the torsional handpiece. Posterior capsule rupture occurred in 4 (15.3% eyes. The mean visual acuity improved significantly after surgery (p<0.001. The postoperative visual acuity was worse than 20/20 in 5 eyes. The cause of the low acuity was amblyopia. Discussion: Successful surgical results and good visual outcome can be achieved with phacoemulsification using the torsional handpiece. (Turk J Ophthalmol 2013; 43: 345-7

  10. Evaluation of left ventricular torsion in children with hypertrophic cardiomyopathy.

    Science.gov (United States)

    Prinz, Christian; Faber, Lothar; Horstkotte, Dieter; Körperich, Hermann; Moysich, Axel; Haas, Nikolaus; Kececioglu, Deniz; Thorsten Laser, Kai

    2014-04-01

    To evaluate the role of torsion in hypertrophic cardiomyopathy in children. A total of 88 children with idiopathic hypertrophic cardiomyopathy (n = 24) and concentric hypertrophy (n = 20) were investigated with speckle-tracking echocardiography and compared with age- and gender-matched healthy controls (n = 44). In hypertrophic cardiomyopathy, we found increased torsion (2.8 ± 1.6 versus 1.9 ± 1.0°/cm [controls], p Hypertrophic cardiomyopathy patients demonstrated a negative correlation between left ventricular muscle mass and torsion (r = -0.7, p hypertrophic cardiomyopathy is characterised by predominantly enhanced systolic basal clockwise rotation. Diastolic untwisting is delayed in both groups. Torsion may be an interesting marker to guide patients with hypertrophic cardiomyopathy.

  11. Amplitude-temperature analysis of hard rubber by torsional vibration

    Czech Academy of Sciences Publication Activity Database

    Šulc, Petr; Pešek, Luděk; Bula, Vítězslav; Cibulka, Jan; Košina, Jan

    2016-01-01

    Roč. 821, č. 2016 (2016), s. 295-302 ISSN 1660-9336 Institutional support: RVO:61388998 Keywords : hard rubber * torsion vibration * finite deformation * parameter identification Subject RIV: BI - Acoustics

  12. Torsion of a wandering spleen | Carapinha | South African Journal of ...

    African Journals Online (AJOL)

    Abstract. Torsion of a wandering spleen is a rare and difficult diagnosis in the paediatric population, with death a possible outcome. In this paper we present our experience of a single case and discuss the embryology and management thereof.

  13. Perinatal testicular torsion: literature review and local experience

    African Journals Online (AJOL)

    IUTT) and postnatal testicular torsion (PTT). IUTT includes cases of vanished testis and testicular mass presenting at birth. Controversies exist regarding the need for urgent exploration and contralateral orchiopexy. The aim of this study is to ...

  14. Damping of Torsional Beam Vibrations by Control of Warping Displacement

    DEFF Research Database (Denmark)

    Høgsberg, Jan Becker; Hoffmeyer, David; Ejlersen, Christian

    2016-01-01

    Supplemental damping of torsional beam vibrations is considered by viscous bimoments acting on the axial warping displacement at the beam supports. The concept is illustrated by solving the governing eigenvalue problem for various support configurations with the applied bimoments represented...

  15. In vitro transcription of a torsionally constrained template

    DEFF Research Database (Denmark)

    Bentin, Thomas; Nielsen, Peter E

    2002-01-01

    of torsionally constrained DNA by free RNAP. We asked whether or not a newly synthesized RNA chain would limit transcription elongation. For this purpose we developed a method to immobilize covalently closed circular DNA to streptavidin-coated beads via a peptide nucleic acid (PNA)-biotin conjugate in principle...... mimicking a SAR/MAR attachment. We used this construct as a torsionally constrained template for transcription of the beta-lactamase gene by Escherichia coli RNAP and found that RNA synthesis displays similar characteristics in terms of rate of elongation whether or not the template is torsionally...... constrained. We conclude that transcription of a natural bacterial gene may proceed with high efficiency despite the fact that newly synthesized RNA is entangled around the template in the narrow confines of torsionally constrained supercoiled DNA....

  16. Axial Torsion of Gangrenous Meckel's Diverticulum Causing Small ...

    African Journals Online (AJOL)

    Axial Torsion of Gangrenous Meckel's Diverticulum Causing. Small Bowel Obstruction. K. Sasikumar, Ravinder Naik Noonavath, G. S. Sreenath, Nanda Kishore Maroju. INTRODUCTION. Meckel's diverticulum (MD) is a commonly encountered congenital anomaly of the small intestine. Autopsy studies estimate overall.

  17. Torsion of an undescended testis located in the inguinal canal.

    Science.gov (United States)

    Weiss, Andrew P; Van Heukelom, Jon

    2012-05-01

    Torsion of undescended testis located within the inguinal canal is a rare finding in the emergency department (ED). This diagnosis can present as undifferentiated abdominal or groin pain, and a full genitourinary examination is essential to making this diagnosis. We present this case to increase awareness among emergency physicians regarding torsion of undescended testis. A 5-year-old boy presented to the ED with abdominal pain and a mass in his right groin. Physical examination and Doppler ultrasound were used to diagnose torsion of undescended testis. In a patient with undescended testis, torsion must be considered as a cause of abdominal or groin pain. Full genitourinary examination is essential to making this diagnosis. Copyright © 2012 Elsevier Inc. All rights reserved.

  18. Perinatal testicular torsion: literature review and local experience ...

    African Journals Online (AJOL)

    IUTT) and postnatal testicular torsion (PTT). IUTT includes cases of vanished testis and testicular mass presenting at birth. Controversies exist regarding the need for urgent exploration and contralateral orchiopexy. The aim of this study is to ...

  19. Torsion-induced optical rotation in isotropic glass media.

    Science.gov (United States)

    Vasylkiv, Yuriy; Adamenko, Dmitro; Kvasnyuk, Oleksiy; Smaga, Ihor; Skab, Ihor; Shopa, Yaroslav; Vlokh, Rostyslav

    2015-03-20

    We have revealed that torsion stresses produce an optical activity effect in initially isotropic glass media. The optical activity caused by spatially inhomogeneous mechanical stresses has been experimentally studied for a standard glass BK7 subjected to torques, using a single-beam polarimetry and a polarizer-sample-analyzer scheme. The torsion-gyration coefficient for the BK7 glass has been determined as (3.96±0.82)×10-17  m3/N.

  20. A fake plane via 2-adic uniformization with torsion

    OpenAIRE

    Allcock, Daniel; Kato, Fumiharu

    2014-01-01

    We adapt the theory of non-Archimedean uniformization to construct a smooth surface from a lattice in PGL3(Q2) that has nontrivial torsion. It turns out to be a fake projective plane, commensurable with Mumford's fake plane yet distinct from it and the other fake planes that arise from 2-adic uniformization by torsion-free groups. As part of the proof, and of independent interest, we compute the homotopy type of the Berkovich space of our plane.

  1. A Numerical Model for Torsion Analysis of Composite Ship Hulls

    Directory of Open Access Journals (Sweden)

    Ionel Chirica

    2012-01-01

    Full Text Available A new methodology based on a macroelement model proposed for torsional behaviour of the ship hull made of composite material is proposed in this paper. A computer program has been developed for the elastic analysis of linear torsion. The results are compared with the FEM-based licensed soft COSMOS/M results and measurements on the scale simplified model of a container ship, made of composite materials.

  2. Outcomes of Surgery for Posterior Polar Cataract Using Torsional Ultrasound

    OpenAIRE

    Selçuk Sızmaz; Aysel Pelit

    2013-01-01

    Purpose: The aim of this study is to report outcomes of surgery for posterior polar cataract using torsional ultrasound. Material and Method: Medical records of 26 eyes of 21 consecutive patients with posterior polar cataract who had cataract surgery using the torsional phacoemulsification were evaluated retrospectively. The surgical procedure used, phacoemulsification parameters, intraoperative complications, and postoperative visual outcome were recorded. Results: Of the 26 eyes...

  3. Torsional Moment Measurement on Bucket Wheel Shaft of Giant Machine

    Directory of Open Access Journals (Sweden)

    Jiří FRIES

    2011-06-01

    Full Text Available Bucket wheel loading at the present time (torsional moment on wheel shaft, peripheral cutting force is determined from electromotor incoming power or reaction force measured on gearbox hinge. Both methods together are weighted by steel construction absorption of driving units and by inertial forces of motor rotating parts. In the article is described direct method of the torsional moment measurement, which eliminates mentioned unfavourable impacts except absorption of steel construction of bucket wheel itself.

  4. Bicavitary effusion secondary to liver lobe torsion in a dog

    Directory of Open Access Journals (Sweden)

    Khan Z

    2016-04-01

    Full Text Available Zaheda Khan,1 Kathryn Gates,2 Stephen A Simpson,31Emergency and Critical Care, Animal Specialty and Emergency Center, Los Angeles, CA, 2Emergency and Critical Care, Advanced Critical Care, Emergency and Specialty Services, Culver City, CA 3Emergency and Critical Care, Southern California Veterinary Specialty Hospital, Irvine, CA, USA Abstract: We described the diagnosis and successful treatment of pleural and peritoneal effusion secondary to liver lobe torsion in a dog. A 12-year-old female spayed Borzoi dog was referred for heart failure. Emergency room thoracic and abdominal ultrasound showed a large volume of pleural effusion with mild peritoneal effusion and an abdominal mass. Pleural fluid analysis classified the effusion as exudative. A complete ultrasound revealed mild peritoneal effusion and decreased blood flow to the right liver lobe. Other causes of bicavitary effusion were ruled out based on blood work, ultrasound, echocardiogram, and computed tomography. The patient was taken to surgery and diagnosed with caudate liver lobe torsion and had a liver lobectomy. At the 2-week postoperative recheck, the patient was doing well and there was complete resolution of the pleural effusion. Liver lobe torsion is a rare occurrence in dogs and can be difficult to diagnose. Clinical signs are nonspecific for liver lobe torsion and patients may present in respiratory distress with significant pleural fluid accumulation. When assessing patients with pleural and peritoneal effusion, liver lobe torsion should be considered as a differential diagnosis.Keywords: pleural effusion, peritoneal effusion, hepatic torsion

  5. A new hybrid longitudinal-torsional magnetostrictive ultrasonic transducer

    Science.gov (United States)

    Karafi, Mohammad Reza; Hojjat, Yousef; Sassani, Farrokh

    2013-06-01

    In this paper, a novel hybrid longitudinal-torsional magnetostrictive ultrasonic transducer (HL-TMUT) is introduced. The transducer is composed of a magnetostrictive exponential horn and a stainless steel tail mass. In this transducer a spiral magnetic field made up of longitudinal and circumferential magnetic fields is applied to the magnetostrictive horn. As a result, the magnetostrictive horn oscillates simultaneously both longitudinally and torsionally in accordance with the Joule and Wiedemann effects. The magnetostrictive exponential horn is designed in such a manner that it has the same longitudinal and torsional resonant frequency. It is made up of ‘2V Permendur’, which has isotropic magnetic properties. The differential equations of the torsional and longitudinal vibration of the horn are derived, and a HL-TMUT is designed with a resonant frequency of 20 573 Hz. The natural frequency and mode shapes of the transducer are considered theoretically and numerically. The experimental results show that this transducer resonates torsionally and longitudinally with frequencies of 20 610 Hz and 20 830 Hz respectively. The maximum torsional displacement is 1.5 mrad m-1 and the maximum longitudinal displacement is 0.6 μm. These are promising features for industrial applications.

  6. Self-assembled nanostructures on vicinal surfaces

    Science.gov (United States)

    Petrovykh, Dmitri Yourievich

    2000-10-01

    One of the first methods for visualizing crystal planes and atomic steps has been step decoration with gold on alkali-halide surfaces. An impressive body of work has been conducted since then on the role of steps in controlling surface diffusion and adsorption rates, catalytic and chemical activity, and other physical and chemical surface properties. Due to these special characteristics, vicinal surfaces offer an approach for creating self-assembled structures with one or more dimensions on nanometer scale. The storage and communications industries have been revolutionized by applications of two-dimensional electron gas confined in thin films, so an interest in one and zero-dimensional systems is not surprising. This work demonstrates how macroscopic amounts of low-dimensional structures can be produced by self-assembly using stepped surfaces as nanometer-scale templates. High-quality templates of step arrays can be prepared on vicinal Si(111) surfaces. Sub-monolayer CaF2/Si(111) heteroepitaxial growth is examined in a series of experiments. A new growth mode is observed in addition to the ones typical in three dimensions. With increasing coverage, the growth front changes from rough to smooth geometry, driven by the elastic interactions between the multiple growth fronts and the surface steps. The mechanism is thus unique to the two-dimensional growth on stepped surfaces. The possible arrangements of the CaF2 self-assembled nanostructures are arrays of stripes or islands, both interesting as potential masks for silicon nanolithography. Anisotropic surface reconstructions, such as Ca and Au induced 3 x 1 and 5 x 2 on Si(111), are effectively self-assembled one-dimensional atomic chains. Reconstructions are single-domain on vicinal surfaces and with odd electron count a metallic one-dimensional state is expected in both the above examples. However in angular-resolved photoemission both appear as semiconductors, and Au-Si(111)5 x 2 exhibits a continuous one

  7. INFLUENCE OF TWIST TECHNOLOGY BY METHOD OF DOUBLE TORSION ON FORMATION OF RESIDUAL TORSIONS AND STRAIGHTNESS OF METAL CORD

    Directory of Open Access Journals (Sweden)

    V. P. Fetisov

    2012-01-01

    Full Text Available The purpose of the present work is research of influence of the technological factors, changing the elasticplastic state of twisted product, on stability within time of residual torsions and straightness of metal cord.

  8. Effects of Friction and Anvil Design on Plastic Deformation during the Compression Stage of High-Pressure Torsion

    Energy Technology Data Exchange (ETDEWEB)

    Song, Yuepeng; Chen, Miaomiao; Xu, Baoyan; Guo, Jing; Xu, Lingfeng; Wang, Zheng [Mechanical and Electronic Engineering College, Tai’an (China); Gao, Dongsheng [Shandong Provincial Key Laboratory of Horticultural Machineries and Equipments, Tai’an (China); Kim, Hyoung Seop [Department of Materials Science and Engineering, Pohang (Korea, Republic of)

    2016-11-15

    Herein, we report the results of our investigation on the effect of friction and anvil design on the heterogeneous plastic-deformation characteristics of copper during the compressive stage of high-pressure torsion (HPT), using the finite element method. The results indicate that the friction and anvil geometry play important roles in the homogeneity of the deformation. These variables affect the heterogeneous level of strain in the HPT compressed disks, as well as the flash in the disk edge region. The heterogeneous plastic deformation of the disks becomes more severe with the increasing depth of the cavity, as anvil angle and friction coefficient increase. However, the homogeneity increases with increases in the wall angle. The length of flash and the area of the dead metal zone increase with the depth of the cavity, while they decrease at a wall angle of 180°.

  9. Effectiveness of lycopene on experimental testicular torsion.

    Science.gov (United States)

    Güzel, Mahmut; Sönmez, Mehmet Fatih; Baştuğ, Osman; Aras, Necip Fazıl; Öztürk, Ayşe Betül; Küçükaydın, Mustafa; Turan, Cüneyt

    2016-07-01

    We aimed to demonstrate the long term effectiveness of lycopene, a precursor of vitamin A, on the testes for ischemia-reperfusion injury. Seventy male Wistar albino rats were used for this experiment. The rats were divided into seven groups. Group 1 served as the control group; group 2 was sham-operated; group 3 received 20mg/kg/day lycopene (intraperitoneally); in group 4, the right testes of rats were kept torted for 2hours and then were detorted and the animals lived for three days; in group 5, the right testes of rats were kept torted for 2hours and then were detorted and the animals lived for ten days; in group 6, the right testes of the rats were kept torted for 2hours and then detorted and the animals received 20mg/kg/day lycopene (intraperitoneally) for three days; in group 7, the right testes of the rats were kept torted for 2hours and then were detorted and the animals received 20mg/kg/day lycopene (intraperitoneally) for ten days. Lycopene was used intraperitoneally. Some of the testes tissues were used for biochemical analyses and the other tissues were used for histological procedures. The Johnsen's score was used for seminiferous tubule deterioration. The TUNEL method was utilized to show apoptosis of testicular tissue. Testosterone levels were measured from blood samples and SOD, MDA, TNF-α, IL-1β and IL-6 measurements were recorded from tissue samples. The results were analyzed statistically. In groups 1, 2 and 3 there was normal testicular structure. Rats in groups 4 and 5 had damaged testicular tissues. In groups 6 and 7, in which we used lycopene, the testes were not better than those in groups 4 and 5. The MSTD and JTBS values were better in group 6, but not in group 7 among the torsion groups. As a result, MDA, SOD, TNF-α and IL-1β were increased and serum testosterone and IL-6 levels were decreased in groups 4 and 5 compared to group 1. There was no improvement in the groups treated with lycopene for therapeutic purposes. It was shown that

  10. Energy harvesting from a multifrequency response of a tuned bending-torsion system

    Science.gov (United States)

    Abdelkefi, A.; Nayfeh, A. H.; Hajj, M. R.; Najar, F.

    2012-07-01

    We investigate the benefits of tuning the frequencies of an energy harvester to extract more energy from a base excitation that comprises three frequency components. The energy harvester is composed of a unimorph cantilever beam with asymmetric tip masses. By adjusting the asymmetry of the tip masses, we can tune this beam-mass structure to harvest energy from multifrequency components of a base excitation. We model the beam using the Euler-Bernoulli beam theory and use the first three global mode shapes of the harvester in a Galerkin procedure to derive a reduced-order model describing its response. We derive an exact analytical solution for the tip deflection, twisting angle, voltage output, and harvested electrical power. Using this solution, we investigate the advantages of harvesting energy from a response that contains multifrequencies in comparison to a response that contains a single frequency by tuning only the fundamental frequency. The advantages of this bending-torsion energy harvester and the effect of its tuning are investigated for different short- and open-circuit configurations. The results show that, through a proper tuning of this bending-torsion harvester, the harvested power can be increased significantly and it can be made to cover a wide range of electrical load resistances.

  11. Contact Angle Goniometer

    Data.gov (United States)

    Federal Laboratory Consortium — Description:The FTA32 goniometer provides video-based contact angle and surface tension measurement. Contact angles are measured by fitting a mathematical expression...

  12. Torsional Behaviour and Finite Element Analysis of the Hybrid Laminated Composite Shafts: Comparison of VARTM with Vacuum Bagging Manufacturing Method

    Directory of Open Access Journals (Sweden)

    Mehmet Emin Taşdelen

    2016-01-01

    Full Text Available Braided sleeve composite shafts are produced and their torsional behavior is investigated. The braided sleeves are slid over an Al tube to create very strong and rigid tubular form shafts and they are in the form of 2/2 twill biaxial fiber fabric that has been woven into a continuous sleeve. Carbon and glass fibers braided sleeves are used for the fabrication of the composite shafts. VARTM (vacuum assisted resin transfer molding and Vacuum Bagging are the two different types of manufacturing methods used in the study. Torsional behaviors of the shafts are investigated experimentally in terms of fabrication methods and various composite materials parameters such as fiber types, layer thickness, and ply angles. Comparing the two methods in terms of the torque forces and strain angles, the shafts producing entirely carbon fiber show the highest torque capacities; however, considering the cost and performance criteria, the hybrid shaft made up of carbon and glass fibers is the optimum solution for average demanded properties. Additionally, FE (finite element model of the shafts was created and analyzed by using ANSYS workbench environment. Results of finite element analysis are compared with the values of twisting angle and torque obtained by experimental tests.

  13. Magnetic resonance imaging findings in adnexial torsion

    Directory of Open Access Journals (Sweden)

    Ronald Meira Castro Trindade

    2010-03-01

    Full Text Available Adnexial torsion is an unusual event, but a major cause of abdominal pain in women. It is often associated with ovarian tumor or cyst, but can occur in normal ovaries, especially in children. The twisting of adnexial structures may involve the ovary or tube, but frequently affects both. In most cases, it is unilateral, with slight predilection for the right side. In imaging findings, increased ovarian volume and adnexial masses are observed, with reduced or absent vascularization. In cases of undiagnosed or untreated complete twist, hemorrhagic necrosis may occur leading to complications; in that, peritonitis is the most frequent. Early diagnosis helps preventing irreversible damage with conservative treatment, thereby saving the ovary. Limitations in performing physical examination, possible inconclusive results in ultrasound and exposure to radiation in computed tomography makes magnetic resonance imaging a valuable tool in emergency assessment of gynecological diseases. The objective of this study was to report two confirmed cases of adnexial twist, emphasizing the contribution of magnetic resonance imaging in the diagnosis of this condition.

  14. Magnetic resonance imaging findings in adnexial torsion

    Energy Technology Data Exchange (ETDEWEB)

    Trindade, Ronald Meira Castro; Quadros, Marianne Siquara de [Hospital Albert Einstein, Sao Paulo, SP (Brazil). Instituto de Ensino e Pesquisa], e-mail: rtrindade@einstein.br; Baroni, Ronaldo Hueb; Rosemberg, Michelle; Racy, Marcelo de Castro Jorge; Tachibana, Adriano [Hospital Albert Einstein, Sao Paulo, SP (Brazil); Funari, Marcelo Buarque de Gusmao [Hospital Albert Einstein, Sao Paulo, SP (Brazil). Imaging Service

    2010-01-15

    Adnexial torsion is an unusual event, but a major cause of abdominal pain in women. It is often associated with ovarian tumor or cyst, but can occur in normal ovaries, especially in children. The twisting of adnexial structures may involve the ovary or tube, but frequently affects both. In most cases, it is unilateral, with slight predilection for the right size. In imaging findings, increased ovarian volume and adnexial masses are observed, with reduced or absent vascularisation. In cases of undiagnosed or untreated complete twist, hemorrhagic necrosis may occur leading to complications; in that, peritonitis is the most frequent. Early diagnosis helps preventing irreversible damage with conservative treatment, thereby saving the ovary. Limitations in performing physical examination, possible inconclusive results in ultrasound and exposure to radiation in computed tomography makes magnetic resonance imaging a valuable tool in emergency assessment of gynecological diseases. The objective of this study was to report two confirmed cases of adnexial twist, emphasizing the contribution of magnetic resonance imaging in the diagnosis of this condition. (author)

  15. Wing-pitch modulation in maneuvering fruit flies is explained by an interplay between aerodynamics and a torsional spring.

    Science.gov (United States)

    Beatus, Tsevi; Cohen, Itai

    2015-08-01

    While the wing kinematics of many flapping insects have been well characterized, understanding the underlying sensory, neural, and physiological mechanisms that determine these kinematics is still a challenge. Two main difficulties in understanding the physiological mechanisms arise from the complexity of the interaction between a flapping wing and its own unsteady flow, as well as the intricate mechanics of the insect wing hinge, which is among the most complicated joints in the animal kingdom. These difficulties call for the application of reduced-order approaches. Here this strategy is used to model the torques exerted by the wing hinge along the wing-pitch axis of maneuvering fruit flies as a damped torsional spring with elastic and damping coefficients as well as a rest angle. Furthermore, we model the air flows using simplified quasistatic aerodynamics. Our findings suggest that flies take advantage of the passive coupling between aerodynamics and the damped torsional spring to indirectly control their wing-pitch kinematics by modulating the spring parameters. The damped torsional-spring model explains the changes measured in wing-pitch kinematics during roll correction maneuvers through modulation of the spring damping and elastic coefficients. These results, in conjunction with the previous literature, indicate that flies can accurately control their wing-pitch kinematics on a sub-wing-beat time scale by modulating all three effective spring parameters on longer time scales.

  16. Single cycle to failure in torsion of three standard and five locking plate constructs.

    Science.gov (United States)

    Cabassu, J B; Kowaleski, M P; Skorinko, J K; Shorinko, J K; Blake, C A; Gaudette, G R; Boudrieau, R J

    2011-01-01

    The biomechanical properties of standard plates and recently designed locking plates were compared in torsion. We hypothesized that titanium (Ti) constructs would have the greatest deformation, and String of Pearls (SOP) constructs the greatest strength and stiffness. Dynamic compression plates (DCP), stainless steel (SS) limited contact (LC)-DCP, Ti LC-DCP, locking compression plate (LCP), 10 mm and 11 mm Advanced Locking Plate System (ALPS) 10 and 11, SOP and Fixin plates were applied to a validated bone model simulating a bridging osteosynthesis. Yield torque (strength), yield angle (deformation) and stiffness were compared using one-way ANOVA with post hoc Tukey (p rationale for selecting these implants for fracture repair likely needs to be based upon their differing biomechanical properties inherent to the diverse implant systems.

  17. Torsion as a dark matter candidate from the Higgs portal

    Science.gov (United States)

    Belyaev, Alexander S.; Thomas, Marc C.; Shapiro, Ilya L.

    2017-05-01

    Torsion is a metric-independent component of gravitation, which may provide a more general geometry than the one taking place within general relativity. On the other hand, torsion could lead to interesting phenomenology in both particle physics and cosmology. In the present work it is shown that a torsion field interacting with the SM Higgs doublet and having a negligible coupling to standard model (SM) fermions is protected from decaying by a Z2 symmetry, and therefore becomes a promising dark matter (DM) candidate. This model provides a good motivation for Higgs portal vector DM scenario. We evaluate the DM relic density and explore direct DM detection and collider constraints on this model to understand its consistency with experimental data and establish the most up-to-date limits on its parameter space. We have found in the model when the Higgs boson is only partly responsible for the generation of torsion mass, there is a region of parameter space where torsion contributes 100% to the DM budget of the Universe. Furthermore, we present the first results on the potential of the LHC to probe the parameter space of minimal scenario with Higgs portal vector DM using mono-jet searches and have found that LHC at high luminosity will be sensitive to the substantial part of model parameter space which cannot be probed by other experiments.

  18. Prune belly syndrome, splenic torsion, and malrotation: a case report.

    Science.gov (United States)

    Tran, Sifrance; Grossman, Eric; Barsness, Katherine A

    2013-02-01

    An 18 year old male with a history of prune belly syndrome (PBS) presented with acute abdominal pain and palpable left upper quadrant mass. Computed tomography (CT) of the abdomen revealed a medialized spleen with a "whirl sign" in the splenic vessels, consistent with splenic torsion. Coincidentally, the small bowel was also noted to be on the right side of the abdomen, while the colon was located on the left, indicative of malrotation. Emergent diagnostic laparoscopy confirmed splenic torsion and intestinal malrotation. Successful laparoscopic reduction of the splenic torsion was achieved, however, conversion to an open procedure by a vertical midline incision was necessary owing to the patient's unique anatomy. Open splenopexy with a mesh sling and Ladd's procedure were subsequently performed. Malrotation and wandering spleen are known, rare associated anomalies in PBS; however, both have not been reported concurrently in a patient with PBS in the literature. In patients with PBS, acute abdominal pain, and an abdominal mass, high clinical suspicion for gastrointestinal malformations and prompt attention can result in spleen preservation and appropriate malrotation management. We present a case of a teenager who presented with a history of PBS, acute abdominal pain, and a palpable abdominal mass. The patient was found to have splenic torsion and intestinal malrotation. The clinical findings, diagnostic imaging, and surgical treatment options of splenic torsion are reviewed. Copyright © 2013 Elsevier Inc. All rights reserved.

  19. Malpractice Litigation and Testicular Torsion: A Legal Database Review.

    Science.gov (United States)

    Colaco, Marc; Heavner, Matthew; Sunaryo, Peter; Terlecki, Ryan

    2015-12-01

    The litigious nature of the American medical environment is a major concern for physicians, with an estimated annual cost of $10 billion. The purpose of this study is to identify causes of litigation in cases of testicular torsion and what factors contribute to verdicts or settlements resulting in indemnity payments. Publicly available jury verdict reports were retrieved from the Westlaw legal database (Thomson Reuters, New York, NY). In order to identify pertinent cases, we used the search terms "medical malpractice" and "testicular torsion" with date ranging from 2000 to 2013. Jury verdicts, depositions, and narrative summaries were evaluated for their medical basis, alleged malpractice, findings, and indemnity payment(s) (if any). Fifty-two cases were identified that were relevant to this study. Fifty-one percent of relevant cases were found in favor of the defendant physician, with the remaining 49% involving an indemnity payment (13% of which were settled). The most commonly sued medical providers were emergency physicians (48% of defendants), with urologists being second most common and making up 23% of the defendant pool. Emergency physicians were significantly more likely to make indemnity payments than urologists. Testicular torsion is a delicate condition and requires expertise in evaluation and treatment. When emergency physicians choose not to consult an urologist for possible torsion, they leave themselves open to litigation risk. When an urologist is involved in torsion litigation, they are rarely unsuccessful in their defense. Finally, ultrasound is no guarantee for success against litigation. Copyright © 2015 Elsevier Inc. All rights reserved.

  20. Autoparallel vs. Geodesic Trajectories in a Model of Torsion Gravity

    Directory of Open Access Journals (Sweden)

    Luis Acedo

    2015-11-01

    Full Text Available We consider a parametrized torsion gravity model for Riemann–Cartan geometry around a rotating axisymmetric massive body. In this model, the source of torsion is given by a circulating vector potential following the celestial parallels around the rotating object. Ours is a variant of the Mao, Tegmark, Guth and Cabi (MTGC model in which the total angular momentum is proposed as a source of torsion. We study the motion of bodies around the rotating object in terms of autoparallel trajectories and determine the leading perturbations of the orbital elements by using standard celestial mechanics techniques. We find that this torsion model implies new gravitational physical consequences in the Solar system and, in particular, secular variations of the semi-major axis of the planetary orbits. Perturbations on the longitude of the ascending node and the perihelion of the planets are already under discussion in the astronomical community, and if confirmed as truly non-zero effects at a statistically significant level, we might be at the dawn of an era of torsion phenomenology in the Solar system.

  1. Autoparallel vs. Geodesic Trajectories in a Model of Torsion Gravity

    Science.gov (United States)

    Acedo, Luis

    2015-11-01

    We consider a parametrized torsion gravity model for Riemann-Cartan geometry around a rotating axisymmetric massive body. In this model, the source of torsion is given by a circulating vector potential following the celestial parallels around the rotating object. Ours is a variant of the Mao, Tegmark, Guth and Cabi (MTGC model) in which the total angular momentum is proposed as a source of torsion. We study the motion of bodies around the rotating object in terms of autoparallel trajectories and determine the leading perturbations of the orbital elements by using standard celestial mechanics techniques. We find that this torsion model implies new gravitational physical consequences in the Solar system and, in particular, secular variations of the semi-major axis of the planetary orbits. Perturbations on the longitude of the ascending node and the perihelion of the planets are already under discussion in the astronomical community, and if confirmed as truly non-zero effects at a statistically significant level, we might be at the dawn of an era of torsion phenomenology in the Solar system.

  2. [Torsion of wandering spleen in a teenager: about a case].

    Science.gov (United States)

    Dème, Hamidou; Akpo, Léra Géraud; Fall, Seynabou; Badji, Nfally; Ka, Ibrahima; Guèye, Mohamadou Lamine; Touré, Mouhamed Hamine; Niang, El Hadj

    2016-01-01

    Wandering or migrating spleen is a rare anomaly which is usually described in children. Complications, which include pedicle torsion, are common and can be life-threatening. We report the case of a 17 year-old patient with a long past medical history of epigastric pain suffering from wandering spleen with chronic torsion of the pedicle. The clinical picture was marked by spontaneously painful epigastric mass, evolved over the past 48 hours. Abdominal ultrasound objectified heterogeneous hypertrophied ectopic spleen in epigastric position and a subcapsular hematoma. Doppler showed a torsion of splenic pedicle which was untwisted 2 turns and a small blood stream on the splenic artery. Abdominal CT scan with contrast injection showed a lack of parenchymal enhancement of large epigastric ectopic spleen and a subcapsular hematoma. The diagnosis of wandering spleen with chronic torsion of the pedicle complicated by necrosis and subcapsular hematoma was confirmed. The patient underwent splenectomy. The postoperative course was uneventful. We here discuss the contribution of ultrasound and CT scan in the diagnosis of wandering spleen with chronic torsion of the pedicle.

  3. A Descriptive Study of Lower Limb Torsional Kinematic Profiles in Children With Spastic Diplegia.

    Science.gov (United States)

    Simon, Anne-Laure; Ilharreborde, Brice; Megrot, Fabrice; Mallet, Cindy; Azarpira, Reza; Mazda, Keyvan; Presedo, Ana; Penneçot, Georges F

    2015-09-01

    Lower limb rotational anomalies in spastic diplegic children with cerebral palsy (CP) are common and difficult to identify through physical examination alone. The identification and treatment of the overall rotational disorders must be considered to restore physiological lever-arms lengths and lever-arms orientation.The aims of the study were to assess the prevalence of lower limb rotational malalignment and to describe the distribution of the different kinematic torsional profiles in children with spastic diplegia. Instrumented gait analysis data from 188 children with spastic diplegia were retrospectively reviewed. None of the patients had undergone surgery previously or received botulinum toxin treatment within 6 months before the review. Kinematic data, collected at the midstance phase, included: pelvic, hip, and ankle rotation and foot progression angle. The prevalence of kinematic rotational deviations was 98.4%. Sixty-one percent of the children walked with an internal foot progression angle and 21% exhibited external alignment. The pelvis was internally rotated in 41% of the cases and externally in another 27%. Hip rotation was internal in 29% and external in 27% of the cases. Ankle rotation was internal in 55% and external in 16% of the cases. Lower limb rotational anomalies involved more than one level in 77% of the limbs. A kinematic compensatory deviation was identified in at least one level in 48% of the limbs. Kinematic rotational anomalies were identified in nearly all the 188 children in the study. The multilevel involvement of lower limb malalignment was not systematically associated with compensatory mechanisms between the levels. Ankle rotational anomalies were the most frequent cause of lower limb torsional deviations followed by pelvic malalignment. Level IV.

  4. Angles in Complex Vector Spaces

    OpenAIRE

    Scharnhorst, K.

    1999-01-01

    The article reviews some of the (fairly scattered) information available in the mathematical literature on the subject of angles in complex vector spaces. The following angles and their relations are considered: Euclidean, complex, and Hermitian angles, (Kasner's) pseudo-angle, the Kaehler angle (synonyms for the latter used in the literature are: angle of inclination, characteristic deviation, holomorphic deviation, holomorphy angle, Wirtinger angle, slant angle).

  5. Effect of Steel Fibers on the Behavior of Over-Reinforced Beams Subjected to Pure Torsion

    National Research Council Canada - National Science Library

    Warnitchai P; Rama Seshu D; Gunneswara Rao T.D

    2010-01-01

    .... Torsion tests on the 15 reinforced steel fiber reinforced concrete beams revealed that, fiber has noticeable effect on the cracking torque and very little effect on the ultimate torsional strength of the member...

  6. Torsional wave propagation in multiwalled carbon nanotubes using nonlocal elasticity

    Science.gov (United States)

    Arda, Mustafa; Aydogdu, Metin

    2016-03-01

    Torsional wave propagation in multiwalled carbon nanotubes is studied in the present work. Governing equation of motion of multiwalled carbon nanotube is obtained using Eringen's nonlocal elasticity theory. The effect of van der Waals interaction coefficient is considered between inner and outer nanotubes. Dispersion relations are obtained and discussed in detail. Effect of nonlocal parameter and van der Waals interaction to the torsional wave propagation behavior of multiwalled carbon nanotubes is investigated. It is obtained that torsional van der Waals interaction between adjacent tubes can change the rotational direction of multiwalled carbon nanotube as in-phase or anti-phase. The group and escape velocity of the waves converge to a limit value in the nonlocal elasticity approach.

  7. Standing torsional waves in a fully saturated, porous, circular cylinder

    CERN Document Server

    Solorza, S; 10.1111/j.1365-246X.2004.02198.x

    2004-01-01

    For dynamic measurement of the elastic moduli of a porous material saturated with viscous fluid using the resonance-bar technique, one also observes attenuation. In this article we have carried out the solution of the boundary-value problem associated with standing torsional oscillations of a finite, poroelastic, circular cylinder cast in the framework of volume-averaged theory of poroelasticity. Analysing this solution by eigenvalue perturbation approach we are able to develop expressions for torsional resonance and temporal attenuation frequencies in which the dependence upon the material properties are transparent. It shows how the attenuation is controlled by the permeability and the fluid properties, and how the resonance frequency drops over its value for the dry solid-frame due to the drag effect of fluid mass. Based upon this work we have a firm basis to determine solid-frame shear modulus, permeability, and tortuosity factor from torsional oscillation experiments.

  8. Fault diagnosis of planetary gearboxes via torsional vibration signal analysis

    Science.gov (United States)

    Feng, Zhipeng; Zuo, Ming J.

    2013-04-01

    Torsional vibration signals are theoretically free from the amplitude modulation effect caused by time variant vibration transfer paths due to the rotation of planet carrier and sun gear, and therefore their spectral structure are simpler than transverse vibration signals. Thus, it is potentially easy and effective to diagnose planetary gearbox faults via torsional vibration signal analysis. We give explicit equations to model torsional vibration signals, considering both distributed gear faults (like manufacturing or assembly errors) and local gear faults (like pitting, crack or breakage of one tooth), and derive the characteristics of both the traditional Fourier spectrum and the proposed demodulated spectra of amplitude envelope and instantaneous frequency. These derivations are not only effective to diagnose single gear fault of planetary gearboxes, but can also be generalized to detect and locate multiple gear faults. We validate experimentally the signal models, as well as the Fourier spectral analysis and demodulation analysis methods.

  9. Mechanical Design of AM Fabricated Prismatic Rods under Torsion

    Directory of Open Access Journals (Sweden)

    Manzhirov Alexander V.

    2017-01-01

    Full Text Available We study the stress-strain state of viscoelastic prismatic rods fabricated or repaired by additive manufacturing technologies under torsion. An adequate description of the processes involved is given by methods of a new scientific field, mechanics of growing solids. Three main stages of the deformation process (before the beginning of growth, in the course of growth, and after the termination of growth are studied. Two versions of statement of two problems are given: (i given the torque, find the stresses, displacements, and torsion; (ii given the torsion, find the stresses, displacements, and torque. Solution methods using techniques of complex analysis are presented. The results can be used in mechanical and instrument engineering.

  10. Abnormalities of Penile Curvature: Chordee and Penile Torsion

    Directory of Open Access Journals (Sweden)

    Sylvia Montag

    2011-01-01

    Full Text Available Congenital chordee and penile torsion are commonly observed in the presence of hypospadias, but can also be seen in boys with the meatus in its orthotopic position. Varying degrees of penile curvature are observed in 4–10% of males in the absence of hypospadias. Penile torsion can be observed at birth or in older boys who were circumcised at birth. Surgical management of congenital curvature without hypospadias can present a challenge to the pediatric urologist. The most widely used surgical techniques include penile degloving and dorsal plication. This paper will review the current theories for the etiology of penile curvature, discuss the spectrum of severity of congenital chordee and penile torsion, and present varying surgical techniques for the correction of penile curvature in the absence of hypospadias.

  11. The quadriceps angle

    DEFF Research Database (Denmark)

    Miles, James Edward; Frederiksen, Jane V.; Jensen, Bente Rona

    2012-01-01

    OBJECTIVES: To evaluate the effect of measurement technique and limb positioning on quadriceps (Q) angle measurement, intra- and interobserver reliability, potential sources of error, and the effect of Q angle variation. STUDY DESIGN: Cadaveric radiographic study and computer modeling. ANIMALS......: Pelvic limbs from red foxes (Vulpes vulpes). METHODS: Q angles were measured on hip dysplasia (HD) and whole limb (WL) view radiographs of each limb between the acetabular rim, mid-point (Q1: patellar center, Q2: femoral trochlea), and tibial tuberosity. Errors of 0.5-2.0 mm at measurement landmarks...... alone and in combination were modeled to identify the effect on Q angle. The effect of measured Q angles on the medial force exerted on the patella (F(MEDIAL) ) was calculated. RESULTS: The HD position yielded significantly (P angles than the WL position. No significant difference...

  12. Sonographic Finding of Extravaginal Testicular Torsion in a Neonate: A Case Report

    Energy Technology Data Exchange (ETDEWEB)

    Son, Jee Young; Kim, Young Jun; Park, Hee Sun; Jeon, Hae Jeong; Park, Hyoung Keun; Paick, Sung Hyun; Kim, Hyeong Gon; Lho, Yong Soo; Lim, So Dug; Jung, Sung Il [Konkuk University School of Medicine, Seoul (Korea, Republic of)

    2011-06-15

    Extravaginal testicular torsion is known to be the predominant mechanism of the torsion in fetuses and neonates. In this torsion, twisting of the spermatic cord occurs outside the sac of the tunica vaginalis in the scrotum. Herein, we describe the sonographic findings of an extravaginal testicular torsion in a newborn baby who presented with a hard scrotal mass. Gray-scale ultrasound (US) showed hypoechoic linear striations in the testis with a thick hyperechoic peritesticular rim. Surgical exploration revealed an extravaginally twisted testis

  13. Effects of mistuning on blade torsional flutter

    Science.gov (United States)

    Srinivasan, A. V.; Kurkov, A.

    1981-01-01

    An analytical model for the prediction of fan blade flutter is presented and evaluated using data from NASA tests on an advanced high performance engine. For the cascade conditions appropriate to the test points studied, the aerodynamic theory cannot predict subcritical flutter. Under the assumptions of a tuned assembly, the imaginary part of the aerodynamic coefficients does indicate flutter for a limited number of interblade phase angles, but these interblade phase angles are close to those at which the acoustic resonance is predicted. Upon using the individual blade frequencies and solving the mistuned system with aerodynamic coupling only, the results show a stable system. Eigenvectors calculated for the mistuned system demonstrate the presence of several harmonics in each mistuned mode. Inclusion of both mechanical and aerodynamic coupling in the solution of the eigenproblem influences not only the frequencies but also damping in the system with a trend toward stability.

  14. Torsional instanton effects in quantum gravity

    CERN Document Server

    Kaul, Romesh K

    2014-01-01

    We show that, in the first order gravity theory coupled to axions, the instanton number of the Giddings-Strominger wormhole can be interpreted as the Nieh-Yan topological index. The axion charge of the baby universes is quantized in terms of the Nieh-Yan integers. Tunneling between universes of different Nieh-Yan charges implies a nonperturbative vacuum state. The associated topological vacuum angle can be identified with the Barbero-Immirzi parameter.

  15. Coupling a small torsional oscillator to large optical angular momentum

    Science.gov (United States)

    Shi, H.; Bhattacharya, M.

    2013-03-01

    We propose a new configuration for realizing torsional optomechanics: an optically trapped windmill-shaped dielectric interacting with Laguerre-Gaussian cavity modes containing both angular and radial nodes. In contrast to existing schemes, our method can couple mechanical oscillators smaller than the optical beam waist to the in-principle unlimited orbital angular momentum that can be carried by a single photon, and thus generate substantial optomechanical interactions. Combining the advantages of small mass, large coupling, and low clamping losses, our work conceptually opens the way for the observation of quantum effects in torsional optomechanics.

  16. Seasonal preponderance in testicular torsion: is it a myth?

    Science.gov (United States)

    Karakan, Tolga; Bagcioglu, Murat; Özcan, Serkan; Telli, Onur; Turgut, Hasan; Özkan, Mehmet; Germiyanoglu, Cancon

    2015-12-01

    In this study, we aimed to investigate the relation of testicular torsion and weather conditions, and to report results from Turkey, a country located between temperate and sub-tropical climate zones. A total of 56 patients that had surgery with the diagnosis of testicular torsion in Ankara Education and Research Hospital Urology Clinic between 2005 and 2014 were included in the study. Age of the patient, side of torsion, date and time at onset of pain, scrotal exploration time, ischemia duration, degree of cord torsion, the surgical procedure performed, and scrotal Doppler ultrasound (USG) findings at the time of diagnosis and 1 month after surgery were retrospectively analyzed. The web archives of Turkish Republic Meteorology General Directorate was used to determine the seasonal and mean temperatures at the time of diagnosis. The data were analyzed with SPSS v. 16 statistical package program using Chi-square, Mann- Whitney U and Wilcoxon tests. The mean age of 56 males included in the study was 18.88 ± 0.73 years. Right testicular torsion was seen in 23, and left testicular torsion was seen in 33 patients. Testicular arterial flow was absent in 37, arterial flow was moderately decreased in 12, and significantly decreased in 7 patients on Doppler USG. Detorsion procedure was performed in 46 patients while 10 patients had orchiectomy. Nine patients were admitted in summer, 14 in fall, 15 in winter, and 18 in spring. The mean air temperature at the time of admittance was 9.31 ± 1.05 °C. The prevalence of testicular torsion was not found different among the seasons (p=0.39). The analysis of air temperature at the time of admittance of the patients revealed that it was below 15 °C in 40 patients while it was above 15 °C in 16 patients, with a significant difference in between (p=0.002). The prevalence of testicular torsion did not change in relation with the seasons. However, it was determined that its prevalence was directly proportional to the air temperature

  17. A black hole with torsion in 5D Lovelock gravity

    Science.gov (United States)

    Cvetković, B.; Simić, D.

    2018-03-01

    We analyze static spherically symmetric solutions of five dimensional (5D) Lovelock gravity in the first order formulation. In the Riemannian sector, when torsion vanishes, the Boulware–Deser black hole represents a unique static spherically symmetric black hole solution for the generic choice of the Lagrangian parameters. We show that a special choice of the Lagrangian parameters, different from the Lovelock Chern–Simons gravity, leads to the existence of a static black hole solution with torsion, the metric of which is asymptotically anti-de Sitter (AdS). We calculate the conserved charges and thermodynamical quantities of this black hole solution.

  18. Catastrophic failure of nacre under pure shear stresses of torsion.

    Science.gov (United States)

    Alghamdi, Saleh; Tan, Ting; Hale-Sills, Christopher; Vilmont, Floyd; Xia, Tian; Yang, Jie; Huston, Dryver; Dewoolkar, Mandar

    2017-10-13

    Nacre, a composite made from biogenic aragonite and proteins, exhibits excellent strength and toughness. Here, we show that nacreous sections can exhibit complete brittle fracture along the tablet interfaces at the proportional limit under pure shear stresses of torsion. We quantitatively separate the initial tablet sliding primarily resisted by nanoscale aragonite pillars from the following sliding resisted by various microscale toughening mechanisms. We postulate that the ductility of nacre can be limited by eliminating tablet interactions during crack propagations. Our findings should help pursuing further insights of layered materials by using torsion.

  19. Primary decomposition of torsion R[X]-modules

    Directory of Open Access Journals (Sweden)

    William A. Adkins

    1994-01-01

    Full Text Available This paper is concerned with studying hereditary properties of primary decompositions of torsion R[X]-modules M which are torsion free as R-modules. Specifically, if an R[X]-submodule of M is pure as an R-submodule, then the primary decomposition of M determines a primary decomposition of the submodule. This is a generalization of the classical fact from linear algebra that a diagonalizable linear transformation on a vector space restricts to a diagonalizable linear transformation of any invariant subspace. Additionally, primary decompositions are considered under direct sums and tensor product.

  20. Pediatric ovarian malignancy presenting as ovarian torsion: incidence and relevance.

    Science.gov (United States)

    Oltmann, Sarah C; Fischer, Anne; Barber, Robert; Huang, Rong; Hicks, Barry; Garcia, Nilda

    2010-01-01

    With ovarian torsion, concern for underlying malignancy in the enlarged ovary has previously driven surgeons to resection. Detorsion alone has been recommended to allow for resolution of edema of the ovary with follow-up ultrasound surveillance to evaluate for a persistent mass, yet is not routine practice. However, the incidence of malignancies presenting as ovarian torsion is not documented. Does the risk of an underlying malignancy justify salpingoophorectomy and decreased fertility? After institutional review board exemption (IRB#-022008-095), a 15(1/2)-year retrospective review was conducted to identify cases of operative ovarian torsion in our medical center. Tumors with neoplastic pathology (malignant and benign) were analyzed and compared with all reported cases in the literature. A total of 114 patients (mean +/- SEM age, 10 years, 2 days to 19 years +/- 0.53) with operatively proven ovarian torsion were identified. Four malignancies (3.5%) and 26 benign neoplasms (23%) were present in this age group. Malignancies consisted of serous borderline tumors (2), juvenile granulosa cell tumor (1), and dysgerminoma (1). All were stage I: the former were stage IA and cured with resection alone, and 1 was a stage IB dysgerminoma, which required chemotherapy. The literature yielded a total of 593 cases of operative ovarian torsion with 9 (1.5%) malignancies and 193 (33%) benign neoplasms. The malignancies were juvenile granulosa cell tumor (n = 4), dysgerminoma (n = 2), serous borderline tumors (n = 2), and 1 undifferentiated adenocarcinoma. By combining our series with 13 in the literature, a 1.8% malignancy rate occurred in 707 patients with ovarian torsion, markedly less than the reported malignancy rate of 10% in children with ovarian masses. Thus, neither a pathologic nor malignant lead point should be assumed in cases of torsion. In our series, which represents the largest series of torsion in the pediatric literature, all malignancies presented as stage I

  1. Ultrasonographic diagnosis of torsion of testicular appendages; Diagnostico por ecografia de la torsion de los apendices testiculares

    Energy Technology Data Exchange (ETDEWEB)

    Esparza, J.; Gonzalez, A.; Cordero, J. L. [Hospital Virgen del Camino. Pamplona (Spain)

    2000-07-01

    To determine the efficacy of ultrasound in boys presenting torsion of a testicular appendage. A series of 30 boys with acute scrotal pain due to torsion of a testicular appendage was studied. Nine patients underwent surgery. The clinical findings and course in the remaining 21 suggested the presence of this abnormality. All of them underwent conventional and color Doppler ultrasound using a 7.5 MHz transducer. In 15 boys, ultrasound images depicted the affected appendage as a mass between the epididymal head and the testicle. In 13 cases, only signs of a inflammatory reaction, with enlargement of the epididymal head and tunicas presenting hyperflow and hydrocele, mimicking acute epididymities. In two cases, the images were normal. There is no definitive, distinguishing ultrasound image corresponding to testicular appendage torsion. Therefore, this diagnostic technique should be accompanied by clinical assessment. (Author) 14 refs.

  2. Determining the energetics of vicinal perovskite oxide surfaces

    NARCIS (Netherlands)

    Wessels, W.A.; Bollmann, Tjeerd Rogier Johannes; Koster, Gertjan; Zandvliet, Henricus J.W.; Rijnders, Augustinus J.H.M.

    2017-01-01

    The energetics of vicinal SrTiO3(001) and DyScO3(110), prototypical perovskite vicinal surfaces, has been studied using topographic atomic force microscopy imaging. The kink formation and strain relaxation energies are extracted from a statistical analysis of the step meandering. Both perovskite

  3. Nanostructured sapphire vicinal surfaces as templates for the growth of self-organized oxide nanostructures

    Energy Technology Data Exchange (ETDEWEB)

    Thune, E., E-mail: elsa.thune@unilim.fr [Laboratoire Sciences des Procedes Ceramiques et de Traitements de Surface (SPCTS), UMR CNRS 6638, ENSCI, 47-73 Avenue Albert Thomas, F-87065 Limoges Cedex (France); Boulle, A. [Laboratoire Sciences des Procedes Ceramiques et de Traitements de Surface (SPCTS), UMR CNRS 6638, ENSCI, 47-73 Avenue Albert Thomas, F-87065 Limoges Cedex (France); Babonneau, D.; Pailloux, F. [Laboratoire de Physique des Materiaux (PHYMAT), UMR CNRS 6630, Universite de Poitiers, Boulevard Marie et Pierre Curie - Teleport 2, BP 30179, F-86962 Futuroscope - Chasseneuil Cedex (France); Hamd, W.; Guinebretiere, R. [Laboratoire Sciences des Procedes Ceramiques et de Traitements de Surface (SPCTS), UMR CNRS 6638, ENSCI, 47-73 Avenue Albert Thomas, F-87065 Limoges Cedex (France)

    2009-11-15

    Vicinal substrates of sapphire with miscut angle of 10 deg. from the (0 0 1) planes towards the [1 1 0] direction have been annealed in air in the range from 1000 to 1500 deg. C. The behaviour of these surfaces has been characterized as a function of the temperature and the thermal treatment time by Atomic Force Microscopy observations. A thermal treatment at 1250 deg. C allows to stabilize a surface made of periodically spaced nanosized step-bunches. Such stepped surfaces were used as template to grow self-patterned epitaxial oxide nanoparticles by thermal annealing of yttria-stabilized zirconia thin films produced by sol-gel dip-coating. Grazing Incidence Small Angle X-ray Scattering and High-Resolution Transmission Electron Microscopy were used to study the morphology of the nanoparticles and their epitaxial relationships with the substrate.

  4. Molecular dynamics study on resonance frequency change due to axial-strain-induced torsions of single-walled carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Jeong Won, E-mail: jwkang@cjnu.ac.k [Department of Computer Engineering, Chungju National University, Chungju 380-702 (Korea, Republic of); Kim, Ki-Sub, E-mail: kks1114@cjnu.ac.k [Department of Chemical and Biological Engineering, Chungju National University, Chungju 380-702 (Korea, Republic of); Byun, Ki Ryang [School of Electrical and Electronic Engineering, Chung-Ang University, Seoul 156-756 (Korea, Republic of); Hwang, Ho Jung, E-mail: hjhwang@cau.ac.k [School of Electrical and Electronic Engineering, Chung-Ang University, Seoul 156-756 (Korea, Republic of)

    2011-03-21

    We investigated, via the classical MD simulation method based on Tersoff-Brenner potential, the fundamental resonance frequency changes of single-walled carbon nanotube (SWCNT) resonators originated from the purely mechanical coupling of the axial-strain-induced torsion (ASIT) response. The fundamental frequency changes were also negligible where the ASIT responses were negligible in achiral SWCNTs whereas those were explicitly found under both compression and tension for the chiral SWCNTs with the obvious ASIT responses. Specially, for SWCNT with the chiral angle of {pi}/12, where the highest ASIT response can be found, the fundamental resonance frequency changes were highest. The fundamental resonance frequencies under the tensioning increased almost linearly with increasing the axial strain whereas they rapidly decreased under compression with increasing the compressive strain. - Research highlights: Frequency changes of nanotube resonators due to the axial-strain-induced torsion. Resonant frequency changes were highest for nanotube with the chiral angle of {pi}/12. Resonant frequencies under tensioning increase linearly with increasing the strain. Resonant frequencies rapidly decrease with increasing the compression.

  5. Angles in hyperbolic lattices

    DEFF Research Database (Denmark)

    Risager, Morten S.; Södergren, Carl Anders

    2017-01-01

    It is well known that the angles in a lattice acting on hyperbolic n -space become equidistributed. In this paper we determine a formula for the pair correlation density for angles in such hyperbolic lattices. Using this formula we determine, among other things, the asymptotic behavior of the den...

  6. Effects of torsion on intervertebral disc gene expression and biomechanics, using a rat tail model.

    Science.gov (United States)

    Barbir, Ana; Godburn, Karolyn E; Michalek, Arthur J; Lai, Alon; Monsey, Robert D; Iatridis, James C

    2011-04-15

    In vitro and in vivo rat tail model to assess effects of torsion on intervertebral disc biomechanics and gene expression. Investigate effects of torsion on promoting biosynthesis and producing injury in rat caudal intervertebral discs. Torsion is an important loading mode in the disc and increased torsional range of motion is associated with clinical symptoms from disc disruption. Altered elastin content is implicated in disc degeneration, but its effects on torsional loading are unknown. Although effects of compression have been studied, the effect of torsion on intervertebral disc gene expression is unknown. In vitro biomechanical tests were performed in torsion on rat tail motion segments subjected to 4 treatments: elastase, collagenase, genipin, control. In vivo tests were performed on rats with Ilizarov-type fixators implanted to caudal motion segments with five 90 minute loading groups: 1 Hz cyclic torsion to ± 5 ± 15° and ± 30°, static torsion to + 30°, and sham. Anulus and nucleus tissues were separately analyzed using qRT-PCR for gene expression of anabolic, catabolic, and proinflammatory cytokine markers. In vitro tests showed decreased torsional stiffness following elastase treatment and no changes in stiffness with frequency. In vivo tests showed no significant changes in dynamic stiffness with time. Cyclic torsion upregulated elastin expression in the anulus fibrosus. Up regulation of TNF-α and IL-1β was measured at ±30°. We conclude that strong differences in the disc response to cyclic torsion and compression are apparent with torsion increasing elastin expression and compression resulting in a more substantial increase in disc metabolism in the nucleus pulposus. Results highlight the importance of elastin in torsional loading and suggest that elastin remodels in response to shearing. Torsional loading can cause injury to the disc at excessive amplitudes that are detectable biologically before they are biomechanically.

  7. Quantum torsion with non-zero standard deviation: Non-perturbative approach for cosmology

    Energy Technology Data Exchange (ETDEWEB)

    Dzhunushaliev, Vladimir, E-mail: v.dzhunushaliev@gmail.com [Dept. Theor. and Nucl. Phys., KazNU, Almaty, 010008 (Kazakhstan); Institute for Basic Research, Eurasian National University, Astana, 010008 (Kazakhstan); Institute of Physicotechnical Problems and Material Science of the NAS of the Kyrgyz Republic, 265 a, Chui Street, Bishkek, 720071 (Kyrgyzstan); Institut für Physik, Universität Oldenburg, Postfach 2503, D-26111 Oldenburg (Germany); Folomeev, Vladimir, E-mail: vfolomeev@mail.ru [Institute of Physicotechnical Problems and Material Science of the NAS of the Kyrgyz Republic, 265 a, Chui Street, Bishkek, 720071 (Kyrgyzstan); Institut für Physik, Universität Oldenburg, Postfach 2503, D-26111 Oldenburg (Germany); Kleihaus, Burkhard, E-mail: b.kleihaus@uni-oldenburg.de [Institut für Physik, Universität Oldenburg, Postfach 2503, D-26111 Oldenburg (Germany); Kunz, Jutta, E-mail: jutta.kunz@uni-oldenburg.de [Institut für Physik, Universität Oldenburg, Postfach 2503, D-26111 Oldenburg (Germany)

    2013-02-12

    Cosmology with non-perturbative quantum corrections resulting from torsion is considered. It is shown that the evolution of closed, open and flat Universes is changed because of the presence of a non-zero dispersion of quantum torsion. The evolution of a Universe with quantum torsion and with one type of average curvature can be similar to the evolution of a Universe without quantum torsion and with another type of average curvature. For the description of the non-perturbative quantum torsion, a vector field approximation is applied.

  8. Correlation of severity of penile torsion with type of hypospadias ...

    African Journals Online (AJOL)

    A. Bhat

    shaft (torsion) toward either side of the midline and ventral curvature was measured using a sterile small protractor around the penile shaft. ... ing with skin re-attachment [2,4,5], dorsal dartos wrap rotation [3], pubicperiostealstitch[6] ... the parents/patients was taken for data evaluation, photographs and inclusion in study.

  9. Torsion of the Spermatic Cord: An Exemplary Early Presentation ...

    African Journals Online (AJOL)

    Unfortunately, in many series, late presentation is still the norm. In the index patient, the presentation time was very short. In our environment, patients with torsion of the spermatic cord can present early and be operated promptly if we can provide public health education, mobile phones, commercial taxis, and good road ...

  10. Static balancing of an inverted pendulum with prestressed torsion bars

    NARCIS (Netherlands)

    Radaelli, G.; Buskermolen, R; Barents, R; Herder, J.L.

    2017-01-01

    This paper presents a method for the design of a statically balanced inverted pendulum. The non-linear moment-rotation characteristic of the pendulum's weight is approximated by a piecewise linear characteristic. Each transition is realized by engaging or disengaging one or more torsion bars, by

  11. Clinical characteristics of adnexal torsion in premenarchal patients.

    Science.gov (United States)

    Ganer Herman, Hadas; Shalev, Amir; Ginat, Shimon; Kerner, Ram; Keidar, Ran; Bar, Jacob; Sagiv, Ron

    2016-03-01

    To compare clinical characteristics of adnexal torsion in premenarchal patients as compared to postmenarchal ones. A retrospective 22-year cohort of all cases of surgically verified adnexal torsion in premenarchal and postmenarchal patients (excluding postmenopausal and pregnant patients). Data collected included symptoms, signs and imaging at presentation, surgical mode, and procedure and histology. 16 cases of adnexal torsion among premenarchal patients were compared to 302 cases among postmenarchal ones. Clinical presentation was similar, notable only for more nausea and vomiting among the premenarchal group. Ovarian cysts were more commonly demonstrated among postmenarchal patients (82.4 and 30.8%, p appearance on ultrasound, which was more common in premenarchal patients (69.3 vs. 17.2%, p trend for detorsion and cystectomy/fenestration, which were more common in postmenarchal surgeries (25 vs. 50.6%, p = 0.06). Histology was similar among both groups, with no cases of malignancy in premenarchal patients. Adnexal torsion in premenarchal patients is rare, presents similarly to older patients, but involves a normal adnexa in 69% of cases, therefore requiring a high index of suspicion in any premenarchal patient with acute onset abdominal pain.

  12. Influence of rigid boundary on the propagation of torsional surface ...

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Earth System Science; Volume 124; Issue 1. Influence of rigid boundary on the propagation of torsional ... rigid boundary, whereas it does at the free boundary. Graphical user interface (GUI) software has been developed using MATLAB 7.5 to generalize the effect of various parameter discussed.

  13. Determination of ocular torsion by means of automatic pattern recognition

    NARCIS (Netherlands)

    Groen, Eric; Bos, Jelte E.; Nacken, Peter F M; De Graaf, Bernd

    A new, automatic method for determination of human ocular torsion (OT) was developed based on the tracking of iris patterns in digitized video images. Instead of quantifying OT by means of cross-correlation of circular iris samples, a procedure commonly applied, this new method automatically selects

  14. Determination of ocular torsion by means of automatic pattern recognition

    NARCIS (Netherlands)

    Groen, E.L.; Bos, J.E.; Nacken, P.F.M.; Graaf, B. de

    1996-01-01

    A new, automatic method for determination of human ocular torsion (OT) was devel-oped based on the tracking of iris patterns in digitized video images. Instead of quanti-fying OT by means of cross-correlation of circular iris samples, a procedure commonly applied, this new method automatically

  15. Torsion of an Epiploic Appendix Pretending as Acute Appendicitis

    Directory of Open Access Journals (Sweden)

    Kamran Ahmad Malik

    2010-07-01

    Full Text Available Torsion of an epiploic appendix is a rare surgical entity. Its unusual symptomatology, wide variation in physical findings and the absence of helpful laboratory and radiological studies makes it very difficult to diagnose pre-operatively. This is a report of this rare entity found in a patient upon diagnostic laparoscopy performed for suspected acute appendicitis

  16. Penile torsion correction by diagonal corporal plication sutures

    Directory of Open Access Journals (Sweden)

    Brent W. Snow

    2009-02-01

    Full Text Available Penile torsion is commonly encountered. It can be caused by skin and dartos adherence or Buck’s fascia attachments. The authors suggest a new surgical approach to solve both problems. If Buck’s fascia involvement is demonstrated by artificial erection then a new diagonal corporal plication suture is described to effectively solve this problem.

  17. The dynamic characteristics of a torsionally flexible metal coupling

    Directory of Open Access Journals (Sweden)

    Krzysztof FILIPOWICZ

    2008-01-01

    Full Text Available At work a structure was presented to the new structural form of the metal coupling about the great torsion susceptibility and description of the research stands and methodology of determining its dynamic characteristics and also to get research findings determining exchanged characterizations which were presented.

  18. Torsional vibration of thin-walled elastic beams with doubly ...

    African Journals Online (AJOL)

    In this paper, the problem of analyzing the torsional vibration of thin-walled elastic beams, with open cross-sections that are doubly symmetric and traversed by moving concentrated masses at constant speeds is addressed. The mathematical model adopted accounts for both the gravitational and inertial effects of the ...

  19. Investigation of torsional vibrations in thick walled hollow poroelastic ...

    Indian Academy of Sciences (India)

    Abstract. This paper deals with the study of torsional vibrations of thick walled hollow poroelastic cylinder using Biot's extension theory. Considering the boundaries to be stress free, the frequency equation is obtained in the presence of dissipation which is transcendental and complex valued in nature. In the special case of ...

  20. Investigation of torsional vibrations in thick walled hollow poroelastic ...

    Indian Academy of Sciences (India)

    This paper deals with the study of torsional vibrations of thick walled hollow poroelastic cylinder using Biot's extension theory. Considering the boundaries to be stress free, the frequency equation is obtained in the presence of dissipation which is transcendental and complex valued in nature. In the special case of ...

  1. Torsional Newton-Cartan geometry and the Schrodinger algebra

    NARCIS (Netherlands)

    Bergshoeff, Eric A.; Hartong, Jelle; Rosseel, Jan

    2015-01-01

    We show that by gauging the Schrodinger algebra with critical exponent z and imposing suitable curvature constraints, that make diffeomorphisms equivalent to time and space translations, one obtains a geometric structure known as (twistless) torsional Newton-Cartan geometry (TTNC). This is a version

  2. Numerical Simulation of Gleeble Torsion Testing of HSLA-65 Steel

    Science.gov (United States)

    2008-04-01

    3800 Torsion machine on AISI 304L and HSLA-65 steels to simulate the friction stir welding of these materials. A photograph of the experimental setup...strain rate levels = 420 flow stress values provided in the dataset for DEFORM 3D. Because of lack of data as well as some inconsistencies between

  3. Torsion of the appendix testis in an undescended testicle | Hajji ...

    African Journals Online (AJOL)

    Physical examination revealed a tender, swollen and painful undescended testis located in the inguinal area with an empty ipsilateral hemiscrotum. Men presenting with pain and undescended testis are more likely to have testicular torsion, malignancy, associated inguinal hernia or trauma. The extra-scrotal position of the ...

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

    African Journals Online (AJOL)

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

  5. Algebraic deformations arising from orbifolds with discrete torsion

    OpenAIRE

    Căldăraru, Andrei; Giaquinto, Anthony; Witherspoon, Sarah

    2002-01-01

    We develop methods for computing Hochschild cohomology groups and deformations of crossed product rings. We use these methods to find deformations of a ring associated to a particular orbifold with discrete torsion, and give a presentation of the center of the resulting deformed ring. This connects with earlier calculations by Vafa and Witten of chiral numbers and deformations of a similar orbifold.

  6. Colonic stricture secondary to torsion of an ovarian cyst

    Energy Technology Data Exchange (ETDEWEB)

    Karmazyn, Boaz; Ziv, Nitza; Horev, Gadi [Department of Diagnostic Radiology, Schneider Children' s Medical Center of Israel, Petah Tiqva (Israel); Steinberg, Ran; Zer, Michael [Pediatric Surgery, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv (Israel)

    2002-01-01

    Intestinal obstruction in the newborn is a potentially life-threatening complication. The most common causes are meconium plug, meconium ileus, intestinal atresia, intestinal malrotation, and Hirschprung's disease. We present an unusual case of intestinal obstruction caused by torsion of an ovarian cyst. The left fimbria and ovary swirled around the sigmoid colon, causing colonic stricture. (orig.)

  7. Adnexal torsion: MR imaging findings of viable ovary

    Energy Technology Data Exchange (ETDEWEB)

    Haque, T.L.; Konishi, J. [Dept. of Nuclear Medicine, Hitachi Medical Corp., Kyoto (Japan); Togashi, K.; Kobayashi, H. [Dept. of Diagnostic and Interventional Imageology, Hitachi Medical Corp., Kyoto (Japan); Fujii, S. [Dept. of Gynecology and Obstetrics, Kyoto Univ. (Japan)

    2000-12-01

    We report a case of torsed ovarian cystic tumor, in which contrast-enhanced high-resolution MR images accurately contributed to the diagnosis of torsion despite the lack of symptoms and to the preoperative evaluation of viability of the edematous ovary. Accurate preoperative assessment by MR images and prompt conservative surgical approach succeeded in salvaging the involved ovary. (orig.)

  8. Penile Torsion: an Overlooked Anomaly with Distal Hypospadias

    African Journals Online (AJOL)

    HussamHassan

    Purpose: To identify the incidence of penile torsion among patients with hypospadias, while using a simple and objective method to measure the degree of rotation. Materials & Methods: From December 2007 to March 2009, all boys presenting to our department for hypospadias repair. (100 boys) were examined for ...

  9. Triorchidism with Torsion | Kumar | Annals of Medical and Health ...

    African Journals Online (AJOL)

    Polyorchidism is a rare anomaly; triorchidism is the commonest type and is frequently associated with cryptorchidism, inguinal hernia, and testicular torsion. It is also reported as an increased risk of testicular malignancy. We report a case of 72.year.old man with left supernumerary testes in the left hemiscrotum.

  10. Torsion Pendulum Experiment at the International Physics Olympiad

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 5; Issue 6. Torsion Pendulum Experiment at the International Physics Olympiad. Sandeep Bala. Classroom Volume 5 Issue 6 June 2000 pp 76-85. Fulltext. Click here to view fulltext PDF. Permanent link:

  11. Effect of irregularity on torsional surface waves in an initially ...

    Indian Academy of Sciences (India)

    The present paper is concerned with the propagation of torsional surface waves in an initially stressedanisotropic porous layer sandwiched between homogeneous and non-homogeneous half-space. We assumethe quadratic inhomogeneity in rigidity and density in the lower half-space and irregularity is taken inthe form of ...

  12. Spectral Action for Torsion with and without Boundaries

    DEFF Research Database (Denmark)

    Iochum, B.; Levy, Cyril Olivier; Vassilevich, D.

    2012-01-01

    We derive a commutative spectral triple and study the spectral action for a rather general geometric setting which includes the (skew-symmetric) torsion and the chiral bag conditions on the boundary. The spectral action splits into bulk and boundary parts. In the bulk, we clarify certain issues...

  13. Penile Torsion: an Overlooked Anomaly with Distal Hypospadias ...

    African Journals Online (AJOL)

    Purpose: To identify the incidence of penile torsion among patients with hypospadias, while using a simple and objective ethod to measure the degree of rotation. Materials & Methods: From December 2007 to March 2009, all boys presenting to our department for hypospadias repair (100 boys) were examined for ...

  14. Portal venous thrombosis developing after torsion of a wandering ...

    African Journals Online (AJOL)

    Torsion of a wandering spleen is a rare disease. The symptoms and signs of this condition are only present when the splenic pedicle torts. The etiological factors are the congenital absence of the ligaments that hold the spleen in its normal anatomic position, or the relaxation of these ligaments resulting from conditions like ...

  15. Torsion of the Spermatic Cord: An Exemplary Early Presentation

    African Journals Online (AJOL)

    2017-10-26

    Oct 26, 2017 ... How to cite this article: Oluyemi OY. Torsion of the spermatic cord: an exemplary early presentation. Niger J Clin Pract 2017;XX;000-000. This is an open access article distributed under the terms of the Creative Commons. Attribution-Non Commercial-Share Alike 3.0 License, which allows others to remix,.

  16. Revisiting the Zassenhaus conjecture on torsion units for the integral ...

    Indian Academy of Sciences (India)

    Abstract. In recent years several new restrictions on integral partial augmentations for torsion units of ZG have been introduced, which have improved the effectiveness of the Luthar–Passi method for checking the Zassenhaus conjecture for specific groups. G. In this note, we report that the Luthar–Passi method with the new ...

  17. Portal Venous Thrombosis Developing after Torsion of a Wandering ...

    African Journals Online (AJOL)

    2017-03-06

    Mar 6, 2017 ... Website: www.njcponline.com. DOI:10.4103/1119-3077.201431. Case Report. How to cite this article: Yilmaz Ö, Kiziltan R, Almali N, Aras A. Portal venous thrombosis developing after torsion of a wandering spleen. Niger J Clin. Pract 2017;20:394-6. This is an open access article distributed under the terms ...

  18. Torsion of bars with regular polygonal sections | Zongo | Global ...

    African Journals Online (AJOL)

    In this article, the study of the torsion of cylindrical bars using large singular finite elements method leads to the resolution of the system of linear equations using MATLAB software. Particularly, the numerical solution of the problem of beams with regular section shows clearly the precision of the method depending upon the ...

  19. Effect of irregularity on torsional surface waves in an initially ...

    Indian Academy of Sciences (India)

    The present paper is concerned with the propagation of torsional surface waves in an initially stressed anisotropic porous layer sandwiched between homogeneous and non-homogeneous half-space. We assume the quadratic inhomogeneity in rigidity and density in the lower half-space and irregularity is taken in the form ...

  20. Tumour, Torsion or Trauma? | Nduhiu | Annals of African Surgery

    African Journals Online (AJOL)

    We present a case of a 22 year old who was managed by various levels of clinicians for a 12 day period prior to testicular exploration which finally revealed testicular torsion. Remarkably, the testis was viable and the finding of a hematoma of the epididymis suggested a history of trauma which was not forthcoming from the ...

  1. Testicular torsion on the Jos Plateau | Ugwu | West African Journal ...

    African Journals Online (AJOL)

    In order to determine the pattern and the factors that influenced outcome, we retrospectively studied fifty-seven patients with torsion of the testis admitted to the Jos University Teaching hospital between August 1993 and July 2001. The age ranged from 2 to 55 years with a mean of 22.7 years. Majority (79%) of the patients ...

  2. Origin of methyl torsional potential barrier–An overview

    Indian Academy of Sciences (India)

    This paper presents the evolution of views on methyl internal rotation potential barrier. Various mechanisms proposed for the origin of torsional barrier in ethane have been reviewed. Inadequacy of one dimensional description of internal rotation has been highlighted in small methyl conjugated molecules in the light of its ...

  3. Influence of rigid boundary on the propagation of torsional surface ...

    Indian Academy of Sciences (India)

    The present work illustrates a theoretical study on the effect of rigid boundary for the propagation of torsional surface wave in an inhomogeneous crustal layer over an inhomogeneous half space. It is believed that the inhomogeneity in the half space arises due to hyperbolic variation in shear modulus and density whereas ...

  4. The Torsion-Extension Coupling in Pretwisted Elastic Beams

    DEFF Research Database (Denmark)

    Krenk, Steen

    1983-01-01

    An explicit asymptotic formula is derived for the untwist of a pretwisted elastic beam subjected to homogeneous extension or equivalently for the longitudinal contraction produced by a torsional moment. It is based on an asymptotic expansion of the three dimensional equations of linear elasticity...

  5. Testicular torsion: Needless testicular loss can be prevented | Njeze ...

    African Journals Online (AJOL)

    Background: The risk of losing the testis is an ever present threat in patients with testicular torsion, who delay before presenting to the surgeon. A retrospective study was carried out to audit patients with acute scrotal pain who came to the Trans Ekulu Hospital Enugu, the promptness of offering them surgical treatment and ...

  6. Timoshenko–Wagner–Kappus Torsion Bending Theory and Wind ...

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 7; Issue 10. Timoshenko–Wagner–Kappus Torsion Bending Theory and Wind Tunnel Balance Design. S P Govinda Raju K R Y Simha. General Article Volume 7 Issue 10 October 2002 pp 54-58 ...

  7. Torsion Dependence of Domain Transition and MI Effect of Melt-Extracted Co68.15Fe4.35Si12.25B13.25Nb1Cu1 Microwires

    Directory of Open Access Journals (Sweden)

    Dawei Xing

    2015-01-01

    Full Text Available We present the torsional stress induced magnetoimpedance (MI effect and surface domain structure evolution of magnetostrictive melt-extracted Co68.15Fe4.35Si12.25B13.25Nb1Cu1 microwires. Experimental results indicate that the surface domain structures observed by magnetic force microscope (MFM transform from the weak circumferential domain of as-cast state to the helical domain under large torsional strain of 81.6 (2π rad/m. Domain wall movement distorts at torsional strain ξ=20.4 (2π rad/m and forms a helical anisotropy with an angle of around 30° versus axial direction of wire. At 15 MHz, the maximum of GMI ratio ΔZ/Z(% increases to 194.4% at ξ=20.4 (2π rad/m from 116.3% of the as-cast state and then decreases to 134.9% at ξ=102.0 (2π rad/m. The torsion magnetoimpedance (TMI ratio ΔZ/Zξ(% is up to 290%. Based on this large torsional strain and high MI ratio, the microwire can be as an referred candidate for high-performance TMI sensor application.

  8. University of Florida Torsion Pendulum for Testing Key LISA Technology

    Science.gov (United States)

    Apple, Stephen; Chilton, Andrew; Olatunde, Taiwo Janet; Hillsberry, Daniel; Parry, Samantha; Ciani, Giacomo; Wass, Peter; Mueller, Guido; Conklin, John

    2018-01-01

    This presentation will describe the design and performance of a new torsion pendulum at the University of Florida used for testing inertial sensors and associated technologies for use in space – based gravitational wave observatories and geodesy missions. In particular this new torsion pendulum facility is testing inertial sensors and associated technology for the upcoming LISA (laser interferometer space antenna) space-based gravitational wave observatory mission. The torsion pendulum apparatus is comprised of a suspended cross bar assembly that has LISA test mass mockups at each of its ends. Two of the test mass mockups are enclosed by capacitive sensors which provide actuation and position sensing. The entire assembly is housed in a vacuum chamber. The pendulum cross-bar converts rotational motion of the test masses about the suspension fiber axis into translational motion. The 22 cm cross bar arm length along with the extremely small torsional spring constant of the suspension fiber results in a near free fall condition in the translational degree-of-freedom orthogonal to both the member and the suspension fiber. The test masses are electrically isolated from the pendulum assembly and their charge is controlled via photoemission using fiber coupled UV LEDS. Position of the test masses is measured using both capacitive and interferometric readout. The broadband sensitivity of the capacitive readout and laser interferometer readout is 30 nm/√Hz and 0.5 nm/√Hz respectively. The performance of the pendulum measured in equivalent acceleration noise acting on a LISA test mass is approximately 3 × 10-13 ms-2/√Hz at 2 mHz. This presentation will also discuss the design and fabrication of a flight-like gravitational reference sensor that will soon be integrated into the torsion pendulum facility. This flight-like GRS will allow for noise performance measurements in a more LISA-like configuration.

  9. Continuity of the torsionless limit as a selection rule for gravity theories with torsion

    CERN Document Server

    Fabbri, Luca

    2014-01-01

    While one can in principle augment gravity theory with torsion, it is generally thought that any such torsion affects would be too small to be of consequence. Here we show that this cannot in general be the case. We show that the limit of vanishing torsion is not necessarily a continuous one, with the theory obtained in the limit not necessarily coinciding with the theory in which torsion had never been present at all. However, for a standard torsion tensor that is antisymmetric in two of its indices we have found two cases in which the vanishing torsion limit is in fact continuous, namely Einstein gravity and conformal gravity. For other gravity theories of common interest to possess a continuous limit the torsion tensor would need to be antisymmetric in all three of its indices.

  10. Photoelectric angle converter

    Science.gov (United States)

    Podzharenko, Volodymyr A.; Kulakov, Pavlo I.

    2001-06-01

    The photo-electric angle transmitter of rotation is offered, at which the output voltage is linear function of entering magnitude. In a transmitter the linear phototransducer is used on the basis of pair photo diode -- operating amplifier, which output voltage is linear function of the area of an illuminated photosensitive stratum, and modulator of a light stream of the special shape, which ensures a linear dependence of this area from an angle of rotation. The transmitter has good frequent properties and can be used for dynamic measurements of an angular velocity and angle of rotation, in systems of exact drives and systems of autocontrol.

  11. The lateral angle revisited

    DEFF Research Database (Denmark)

    Morgan, Jeannie; Lynnerup, Niels; Hoppa, R.D.

    2013-01-01

    This article presents the results of a validation study of a previously published method of sex determination from the temporal bone. The purpose of this study was to evaluate the lateral angle method for the internal acoustic canal for accurately determining the sex of human skeletal remains using...... measurements taken from computed tomography (CT) scans. Previous reports have observed that the lateral angle size in females is significantly larger than in males. The method was applied to an independent series of 77 postmortem CT scans (42 males, 35 females) to validate its accuracy and reliability....... The mean lateral angle of the internal acoustic canal was found to be larger in females (46.5°) than in males (43.4°). However, the difference was not statistically significant and the sex differences reported in previous studies were not substantiated. In light of the observed results, the lateral angle...

  12. Reliability of the assessment of lower limb torsion using computed tomography: analysis of five different techniques

    Energy Technology Data Exchange (ETDEWEB)

    Liodakis, Emmanouil; Doxastaki, Iosifina; Chu, Kongfai; Krettek, Christian; Gaulke, Ralph; Citak, Musa [Hannover Medical School, Trauma Department, Hannover (Germany); Kenawey, Mohamed [Sohag University Hospital, Orthopaedic Surgery Department, Sohag (Egypt)

    2012-03-15

    Various methods have been described to define the femoral neck and distal tibial axes based on a single CT image. The most popular are the Hernandez and Weiner methods for defining the femoral neck axis and the Jend, Ulm, and bimalleolar methods for defining the distal tibial axis. The purpose of this study was to calculate the intra- and interobserver reliability of the above methods and to determine intermethod differences. Three physicians separately measured the rotational profile of 44 patients using CT examinations on two different occasions. The average age of patients was 36.3 {+-} 14.4 years, and there were 25 male and 19 female patients. After completing the first two sessions of measurements, one observer chose certain cuts at the levels of the femoral neck, femoral condylar area, tibial plateau, and distal tibia. The three physicians then repeated all measurements using these CT cuts. The greatest interclass correlation coefficients were achieved with the Hernandez (0.99 intra- and 0.93 interobserver correlations) and bimalleolar methods (0.99 intra- and 0.92 interobserver correlations) for measuring the femoral neck and distal tibia axes, respectively. A statistically significant decrease in the interobserver median absolute differences could be achieved through the use of predefined CT scans only for measurements of the femoral condylar axis and the distal tibial axis using the Ulm method. The bimalleolar axis method underestimated the tibial torsion angle by an average of 4.8 and 13 compared to the Ulm and Jend techniques, respectively. The methods with the greatest inter- and intraobserver reliabilities were the Hernandez and bimalleolar methods for measuring femoral anteversion and tibial torsion, respectively. The high intermethod differences make it difficult to compare measurements made with different methods. (orig.)

  13. Torsion and bending properties of shape memory and superelastic nickel-titanium rotary instruments.

    Science.gov (United States)

    Ninan, Elizabeth; Berzins, David W

    2013-01-01

    Recently introduced into the market are shape memory nickel-titanium (NiTi) rotary files. The objective of this study was to investigate the torsion and bending properties of shape memory files (CM Wire, HyFlex CM, and Phoenix Flex) and compare them with conventional (ProFile ISO and K3) and M-Wire (GT Series X and ProFile Vortex) NiTi files. Sizes 20, 30, and 40 (n = 12/size/taper) of 0.02 taper CM Wire, Phoenix Flex, K3, and ProFile ISO and 0.04 taper HyFlex CM, ProFile ISO, GT Series X, and Vortex were tested in torsion and bending per ISO 3630-1 guidelines by using a torsiometer. All data were statistically analyzed by analysis of variance and the Tukey-Kramer test (P = .05) to determine any significant differences between the files. Significant interactions were present among factors of size and file. Variability in maximum torque values was noted among the shape memory files brands, sometimes exhibiting the greatest or least torque depending on brand, size, and taper. In general, the shape memory files showed a high angle of rotation before fracture but were not statistically different from some of the other files. However, the shape memory files were more flexible, as evidenced by significantly lower bending moments (P < .008). Shape memory files show greater flexibility compared with several other NiTi rotary file brands. Copyright © 2013 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  14. Effectiveness of damped braces to mitigate seismic torsional response of unsymmetric-plan buildings

    Science.gov (United States)

    Mazza, Fabio; Pedace, Emilia; Favero, Francesco Del

    2017-02-01

    The seismic retrofitting of unsymmetric-plan reinforced concrete (r.c.) framed buildings can be carried out by the incorporation of damped braces (DBs). Yet most of the proposals to mitigate the seismic response of asymmetric framed buildings by DBs rest on the hypothesis of elastic (linear) structural response. The aim of the present work is to evaluate the effectiveness and reliability of a Displacement-Based Design procedure of hysteretic damped braces (HYDBs) based on the nonlinear behavior of the frame members, which adopts the extended N2 method considered by Eurocode 8 to evaluate the higher mode torsional effects. The Town Hall of Spilinga (Italy), a framed structure with an L-shaped plan built at the beginning of the 1960s, is supposed to be retrofitted with HYDBs to attain performance levels imposed by the Italian seismic code (NTC08) in a high-risk zone. Ten structural solutions are compared by considering two in-plan distributions of the HYDBs, to eliminate (elastic) torsional effects, and different design values of the frame ductility combined with a constant design value of the damper ductility. A computer code for the nonlinear dynamic analysis of r.c. spatial framed structures is adopted to evaluate the critical incident angle of bidirectional earthquakes. Beams and columns are simulated with a lumped plasticity model, including flat surface modeling of the axial load-biaxial bending moment elastic domain at the end sections, while a bilinear law is used to idealize the behavior of the HYDBs. Damage index domains are adopted to estimate the directions of least seismic capacity, considering artificial earthquakes whose response spectra match those adopted by NTC08 at serviceability and ultimate limit states.

  15. Comparison of left ventricular torsion and strain with biventricular pacing in patients with underlying right bundle branch block versus those with left bundle branch block.

    Science.gov (United States)

    De, Sabe; Popović, Zoran B; Verhaert, David; Dresing, Thomas; Wilkoff, Bruce; Starling, Randall; Tang, W H Wilson; Thomas, James D; Grimm, Richard A

    2015-04-01

    The benefits of biventricular pacing in patients with cardiac resynchronization therapy (CRT) remain poorly understood in those with right bundle branch block (RBBB). The aim of this study was to examine the differences in several speckle tracking-derived parameters, including left ventricular torsion and longitudinal strain with CRT on and off for patients with underlying left bundle branch block (LBBB) and RBBB. Twelve patients with CRT and RBBB were compared with a similar group of patients with underlying LBBB who were sent for evaluation and atrioventricular optimization. Echocardiographic images were acquired with biventricular pacing on and off. The 2 groups had similar baseline characteristics, including age, the ejection fraction, and QRS duration. During intrinsic conduction (CRT off), patients with LBBB had lower torsion angles than those with RBBB (2.3 ± 1.0° in those with LBBB vs 6.3 ± 1.0° in those with RBBB, p = 0.03) but trended toward improvements in torsional parameters, including torsional angle and peak untwisting velocity with CRT on, whereas these parameters worsened in patients with RBBB. Compared with CRT off, analyses of septal and lateral strain curves showed significant improvements in septal strain during 100% and 200% of systole with CRT on in patients with LBBB, whereas biventricular pacing resulted in a trend toward worsening of septal strain in patients with RBBB. Negligible changes were noted in lateral strain values. In conclusion, CRT favorably improves regional mechanics in patients with LBBB primarily involving the ventricular septum, with a negligible positive impact on cardiac function in patients with underlying RBBB. Copyright © 2015 Elsevier Inc. All rights reserved.

  16. Angle-Ply Weaving

    Science.gov (United States)

    Farley, Gary L.

    1990-01-01

    Bias-direction or angle-ply weaving is proposed new process for weaving fibers along bias in conventional planar fabric or in complicated three-dimensional multilayer fabric preform of fiber-reinforced composite structure. Based upon movement of racks of needles and corresponding angle yarns across fabric as fabric being formed. Fibers woven along bias increases shear stiffness and shear strength of preform, increasing value of preform as structural member.

  17. Deposition and properties of Fe(Se,Te) thin films on vicinal CaF2 substrates

    Science.gov (United States)

    Bryja, Hagen; Hühne, Ruben; Iida, Kazumasa; Molatta, Sebastian; Sala, Alberto; Putti, Marina; Schultz, Ludwig; Nielsch, Kornelius; Hänisch, Jens

    2017-11-01

    We report on the growth of epitaxial Fe1+δ Se0.5Te0.5 thin films on 0°, 5°, 10°, 15° and 20° vicinal cut CaF2 single crystals by pulsed laser deposition. In situ electron and ex situ x-ray diffraction studies reveal a tilted growth of the Fe1+δ Se0.5Te0.5 films, whereby under optimized deposition conditions the c-axis alignment coincides with the substrate [001] tilted axis up to a vicinal angle of 10°. Atomic force microscopy shows a flat island growth for all films. From resistivity measurements in longitudinal and transversal directions, the ab- and c-axis components of resistivity are derived and the mass anisotropy parameter is determined. Analysis of the critical current density indicates that no effective c-axis correlated defects are generated by vicinal growth, and pinning by normal point core defects dominates. However, for H∣∣ab the effective pinning centers change from surface defects to point core defects near the superconducting transition due to the vicinal cut. Furthermore, we show in angular-dependent critical current density data a shift of the ab-planes maxima position with the magnetic field strength.

  18. Faults--Drakes Bay and Vicinity Map Area, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data of faults for the geologic and geomorphologic map of the Drakes Bay and Vicinity map area, California. The vector data file is...

  19. BackscatterB [EM300]--Monterey Canyon and Vicinity, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the acoustic-backscatter map of Monterey Canyon and Vicinity map area, California. Backscatter data are provided as separate...

  20. BackscatterC [7125]--Monterey Canyon and Vicinity, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the acoustic-backscatter map of Monterey Canyon and Vicinity map area, California. Backscatter data are provided as separate...

  1. Folds--Monterey Canyon and Vicinity Map Area, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the folds for the geologic and geomorphic map of Monterey Canyon and Vicinity, California. The vector data file is included in...

  2. Backscatter A [8101]--Drakes Bay and Vicinity, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the acoustic-backscatter map of Drakes bay and Vicinity map area, California. Backscatter data are provided as separate grids...

  3. Backscatter C [7125]--Drakes Bay and Vicinity, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the acoustic-backscatter map of Drakes bay and Vicinity map area, California. Backscatter data are provided as separate grids...

  4. Faults--Monterey Canyon and Vicinity Map Area, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the faults for the geologic and geomorphic map of Monterey Canyon and Vicinity, California. The vector data file is included in...

  5. establishment of background radiation dose rate in the vicinity

    African Journals Online (AJOL)

    nb

    .ac.tz). *Permanent address: Department of Physics, University of Dodoma. P. O. Box 339 Dodoma. ABSTRACT. The absorbed dose rate in air in the vicinity of the proposed Manyoni uranium mining project located in Singida region, Tanzania, ...

  6. Folds--Drakes Bay and Vicinity Map Area, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data of folds for the geologic and geomorphologic map of the Drakes Bay and Vicinity map area, California. The vector data file is...

  7. Paleoshorelines--Monterey Canyon and Vicinity Map Area, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the paleoshorelines for the geologic and geomorphic map of Monterey Canyon and Vicinity, California. The vector data file is...

  8. Aerial survey of sea otters in the Cordova vicinity

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The movement of significantly large numbers of sea otters into the Cordova vicinity has generated a local storm of protest concerning the ability of sea otters to...

  9. Submesoscale Dispersion in the Vicinity of the Deepwater Horizon Spill

    Science.gov (United States)

    2014-09-02

    RESPONSIBLE PERSON 19b. TELEPHONE NUMBER (Include area code) 11-03-2014 Journal Article Submesoscale dispersion in the vicinity of the Deepwater ...ecosystems, society, and the economy as evidenced by the Deepwater Horizon oil spill in the Gulf of Mexico in 2010 and the Fukushima nuclear plant...vicinity of the Deepwater Horizon spill Andrew C. Pojea, Tamay M. Özgökmenb,1, Bruce L. Lipphardt, Jr.c, Brian K. Hausb, Edward H. Ryanb, Angelique C

  10. Application of Concrete Segment Panels for Reduction of Torsional Vibration Responses of Girder Bridges

    Directory of Open Access Journals (Sweden)

    Kwark Jong-Won

    2015-01-01

    Full Text Available The dynamic flexural behaviour of railway bridges is influenced by the torsional behaviour, and the flexural response tends to be amplified as the flexural natural frequency (the 1st vibrational mode and torsional frequency (the 2nd vibrational mode are adjoining. To avoid this phenomenon, the installation of concrete segment panels was considered for the reinforcement of torsional stiffness by connecting bottom flanges between girders. This alternative can increase the torsional stiffness by providing the restraint in torsional vibration and reduce the influence of torsional behaviour on the amplification of flexural responses. This study investigates the effect of the concrete segment panels on the control of torsional dynamic responses and on the increment of torsional frequency. The excitation tests on a full-size bridge specimen with 30 m span length were conducted with respect to the installation length of concrete panels up to 7 m from each ends. The results show that the installation of concrete segment panel augments the torsional frequency up to 22 % while the flexural frequency keeps its original value. It is concluded that the dynamic behaviour of girder bridges can be controlled by the adjustment of installation length of concrete panels, thereby reducing the torsional responses.

  11. Influence of humeral torsion on interpretation of posterior shoulder tightness measures in overhead athletes.

    Science.gov (United States)

    Myers, Joseph B; Oyama, Sakiko; Goerger, Benjamin M; Rucinski, Terri Jo; Blackburn, J Troy; Creighton, R Alexander

    2009-09-01

    To measure the influence of humeral torsion on interpretation of clinical indicators of posterior shoulder tightness in overhead athletes. Cross-sectional control group comparison. A university-based sports medicine research laboratory. Twenty-nine healthy intercollegiate baseball players and 25 college-aged control individuals with no history of participation in overhead athletics were enrolled. In all participants, bilateral humeral rotation and humeral horizontal adduction variables were measured with a digital inclinometry. Bilateral humeral torsion was measured with ultrasonography. Group and limb comparisons were made for clinical indicators of posterior shoulder tightness (humeral rotation and horizontal adduction variables) and humeral torsion variables. The relationship between humeral torsion and clinical indicators of posterior shoulder tightness were established. The dominant limb of the baseball players demonstrated greater humeral torsion, and less internal rotation and total rotation range of motion, compared with control participants and the nondominant limb in both groups. Once corrected for torsion, no group or limb differences in internal rotation were present. Statistically significant relationships existed between the amount of humeral torsion and measures of posterior shoulder tightness. Although limb differences in clinical indicators of posterior tightness exist in healthy overhead athletes, these measures appear to be influenced by humeral torsion rather than soft tissue tightness. Once torsion is accounted for, the limb differences observed clinically were minimal in healthy overhead athletes. When possible, accounting for humeral torsion when interpreting clinical measures of posterior shoulder tightness may aid in treatment decisions.

  12. The effect to bending fatigue strength of 65 mn under torsion strain-hardening

    Science.gov (United States)

    Zou, Guangping; Xue, Qichao; Li, Wei

    2010-03-01

    Bending Fatigue experiments for 65Mn are carried out to study the effects of torsion strain-hardening. Firstly bending fatigue specimens are pre-twisted for torsion strain-hardening by using torsion testing machine. And specimens are divided as 8 groups and each group has 8 specimens. A series of plastic shear strains are applied to each group. Then bending fatigue experiments are carried on to estimate torsion fatigue strength by fatigue bending machine. Finally micrograms of fatigue damage are taken by stereo microscope. The test results showed that torsion strain-hardening has a certain effects that when torsion plastic strain is small, bending fatigue strength is increased. Oppositely, when torsion plastic strain is large, bending fatigue strength are all decreased in a large rate compared with specimens without torsion strain-hardening. Comparing different test results and corresponding paragraphs obtained from stereo microscope, a reasonable explanation can be deduced by using metal micromechanics theory and crystal lattice dislocation theory. A possible reason is that when torsion plastic strain is small, there will be more dislocation in crystal lattice, which can raise the fatigue strength. And when torsion plastic strain is large, dislocations are piled up in some position which can bring flaws under loads, which reduce the fatigue strength of specimen.

  13. Testicular torsion and weather conditions: analysis of 21,289 cases in Brazil

    Directory of Open Access Journals (Sweden)

    Fernando Korkes

    2012-04-01

    Full Text Available PURPOSE: The hypothesis of association between testicular torsion and hyperactive cremasteric reflex, worsened by cold weather, has not been proved. Thirteen studies in the literature evaluated this issue, with inconclusive results. The aim of the present study was to evaluate the seasonality of testicular torsion in a large subset of patients surgically treated in Brazil, and additionally to estimate the incidence of testicular torsion. MATERIALS AND METHODS: Brazilian Public Health System Database was assessed from 1992-2010 to evaluate hospital admissions associated with treatment of testicular torsion. Average monthly temperature between 1992-2010 was calculated for each region. RESULTS: We identified 21,289 hospital admissions for treatment of testicular torsion. There was a higher number of testicular torsions during colder months (p = 0.002. To estimate the incidence of testicular torsion, we have related our findings to data from the last Brazilian census (2010. In 2010, testicular torsion occurred in 1.4:100,000 men in Brazil. CONCLUSIONS:Testicular torsion occurred at an annual incidence of approximately 1.4:100,000 men in Brazil in 2010. Seasonal variations do occur, with a significant increase of events during winter. Our findings support the theory of etiological role of cold weather to the occurrence of testicular torsion. Strategies to prevent these events can be based on these findings.

  14. Three-dimensional assessment of curvature, torsion, and canal flare index of the humerus of skeletally mature nonchondrodystrophic dogs.

    Science.gov (United States)

    Smith, Emily J; Marcellin-Little, Denis J; Harrysson, Ola L A; Griffith, Emily H

    2017-10-01

    OBJECTIVE To assess 3-D geometry of the humerus of dogs and determine whether the craniocaudal canal flare index (CFI) is associated with specific geometric features. SAMPLE CT images (n = 40) and radiographs (38) for 2 groups of skeletally mature nonchondrodystrophic dogs. PROCEDURES General dimensions (length, CFI, cortical thickness, and humeral head offset), curvature (shaft, humeral head, and glenoid cavity), version (humeral head and greater tubercle), and torsion were evaluated on CT images. Dogs were allocated into 3 groups on the basis of the craniocaudal CFI, and results were compared among these 3 groups. The CT measurements were compared with radiographic measurements obtained for another group of dogs. RESULTS Mean ± SD humeral head version was -75.9 ± 9.6° (range, -100.7° to -59.4°). Mean mechanical lateral distal humeral angle, mechanical caudal proximal humeral angle, and mechanical cranial distal humeral angle were 89.5 ± 3.5°, 50.2 ± 4.5°, and 72.9 ± 7.8°, respectively, and did not differ from corresponding radiographic measurements. Mean humeral curvature was 20.4 ± 4.4° (range, 9.6° to 30.5°). Mean craniocaudal CFI was 1.74 ± 0.18 (range, 1.37 to 2.10). Dogs with a high craniocaudal CFI had thicker cranial and medial cortices than dogs with a low craniocaudal CFI. Increased body weight was associated with a lower craniocaudal CFI. Radiographic and CT measurements of craniocaudal CFI and curvature differed significantly. CONCLUSIONS AND CLINICAL RELEVANCE CT-based 3-D reconstructions allowed the assessment of shaft angulation, torsion, and CFI. Radiographic and CT measurements of shaft curvature and CFI may differ.

  15. Torsion of the fallopian the mimicking appendicitis in a pregnant woman; Torsion de la trompa de Falopio en una mujer gestante simulando apendicitis

    Energy Technology Data Exchange (ETDEWEB)

    Tapia-Vine, M.; Pedrosa, I.; Escribano, N. [Hospital Clinico San Carlos (Spain)

    2000-07-01

    Isolated torsion of the fallopian tube is an uncommon entity. Given the difficulties involved in the preoperative diagnosis, the ultrasound findings characteristic of this anomaly are not widely known. We present a case of tubal torsion associated with a cyst, describing the ultrasound images in our case and those reported in the literature. (Author) 18 refs.

  16. Clinical assessment of left ventricular systolic torsion: effects of myocardial infarction and ischemia.

    Science.gov (United States)

    Bansal, Manish; Leano, Rodel L; Marwick, Thomas H

    2008-08-01

    The helical arrangement of myocardial fibers leads to left ventricular (LV) torsion, a vital contributor to systolic and diastolic function. Rotation and torsion can now be measured; we sought to determine the utility of torsion as a marker of LV function at rest and after stress in patients with myocardial infarctions (MIs) and ischemia. Dobutamine echocardiography was performed in 125 patients. After the exclusion of 40 patients with suboptimal images, LV systolic rotation and torsion were measured offline using speckle-tracking echocardiography in 44 patients with and 41 without prior MIs. Hemodynamic findings and the extent of infarction and ischemia were correlated with length-corrected torsion measurements at baseline and at peak-dose dobutamine. Resting global and regional LV systolic torsion were significantly reduced in patients with compared with those without previous MIs (1.16 +/- 1.15 degrees /cm vs 3.16 +/- 1.3 degrees /cm, P anteroapical or inferoposterior infarcts (1.81 +/- 1.13 degrees /cm vs 2.27 +/- 1.18 degrees /cm, P = NS) and no differences in regional torsion. Torsion was most impaired in patients with multiple areas of infarction (1.03 +/- 0.89 degrees /cm, P < .001). However, dobutamine-induced ischemia (2.59 +/- 1.14 ischemic segments) had no effect on global and regional systolic torsion at peak dose or change in torsion from rest to peak dose. The influence of MI on LV systolic torsion appears to be related to infarct size rather than site, and torsion was an independent determinant of resting function. LV torsion was not significantly influenced by stress-induced myocardial ischemia.

  17. NASA/University JOint VEnture (JOVE) Program: Transverse Shear Moduli Using the Torsional Responses of Rectangular Laminates

    Science.gov (United States)

    Bogan, Sam

    2001-01-01

    The first year included a study of the non-visible damage of composite overwrapped pressure vessels with B. Poe of the Materials Branch of Nasa-Langley. Early determinations showed a clear reduction in non-visible damage for thin COPVs when partially pressurized rather than unpressurized. Literature searches on Thicker-wall COPVs revealed surface damage but clearly visible. Analysis of current Analytic modeling indicated that that current COPV models lacked sufficient thickness corrections to predict impact damage. After a comprehensive study of available published data and numerous numerical studies based on observed data from Langley, the analytic framework for modeling the behavior was determined lacking and both Poe and Bogan suggested any short term (3yr) result for Jove would be overly ambitious and emphasis should be placed on transverse shear moduli studies. Transverse shear moduli determination is relevant to the study of fatigue, fracture and aging effects in composite structures. Based on the techniques developed by Daniel & Tsai, Bogan and Gates determined to verify the results for K3B and 8320. A detailed analytic and experimental plan was established and carried out that included variations in layup, width, thickness, and length. As well as loading rate variations to determine effects and relaxation moduli. The additional axial loads during the torsion testing were studied as was the placement of gages along the composite specimen. Of the proposed tasks, all of tasks I and 2 were completed with presentations given at Langley, SEM conferences and ASME/AIAA conferences. Sensitivity issues with the technique associated with the use of servohydraulic test systems for applying the torsional load to the composite specimen limited the torsion range for predictable and repeatable transverse shear properties. Bogan and Gates determined to diverge on research efforts with Gates continuing the experimental testing at Langley and Bogan modeling the apparent non

  18. MAJOR OIL PLAYS IN UTAH AND VICINITY

    Energy Technology Data Exchange (ETDEWEB)

    Thomas C. Chidsey; Craig D. Morgan; Kevin McClure; Grant C. Willis

    2003-09-01

    Arizona. Outcrop analogs are found in the stratigraphically equivalent Navajo Sandstone of southern Utah which displays large-scale dunal cross-strata with excellent reservoir properties and interdunal features such as oases, wadi, and playa lithofacies with poor reservoir properties. Hydrocarbons in the Paradox Formation are stratigraphically trapped in carbonate buildups (or phylloid-algal mounds). Similar carbonate buildups are exposed in the Paradox along the San Juan River of southeastern Utah. Reservoir-quality porosity may develop in the types of facies associated with buildups such as troughs, detrital wedges, and fans, identified from these outcrops. When combined with subsurface geological and production data, these outcrop analogs can improve (1) development drilling and production strategies such as horizontal drilling, (2) reservoir-simulation models, (3) reserve calculations, and (4) design and implementation of secondary/tertiary oil recovery programs and other best practices used in the oil fields of Utah and vicinity. During this quarter, technology transfer activities consisted of exhibiting the project plans, objectives, and products at a booth at the 2003 annual convention of the American Association of Petroleum Geologists. The project home page was updated on the Utah Geological Survey Internet web site.

  19. A method of measuring micro-impulse with torsion pendulum based on multi-beam laser heterodyne

    Science.gov (United States)

    Li, Yan-Chao; Wang, Chun-Hui

    2012-02-01

    In this paper, we propose a novel method of multi-beam laser heterodyne measurement for micro-impulse. The measurement of the micro-impulse, which is converted into the measurement of the small tuning angle of the torsion pendulum, is realized by considering the interaction between pulse laser and working medium. Based on Doppler effect and heterodyne technology, the information regarding the small tuning angle is loaded to the frequency difference of the multi-beam laser heterodyne signal by the frequency modulation of the oscillating mirror, thereby obtaining many values of the small tuning angle after the multi-beam laser heterodyne signal demodulation simultaneously. Processing these values by weighted-average, the small tuning angle can be obtained accurately and the value of the micro-impulse can eventually be calculated. Using Polyvinylchlorid+2%C as a working medium, this novel method is used to simulate the value of the micro-impulse by MATLAB which is generated by considering the interaction between the pulse laser and the working medium, the obtained result shows that the relative error of this method is just 0.5%.

  20. A torsional artificial muscle from twisted nitinol microwire

    Science.gov (United States)

    Mirvakili, Seyed M.; Hunter, Ian W.

    2017-04-01

    Nitinol microwires of 25 μm in diameter can have tensile actuation of up to 4.5% in less than 100 ms. A work density of up to 480 MPa can be achieved from these microwires. In the present work, we are showing that by twisting the microwires in form of closed-loop two-ply yarn we can create a torsional actuator. We achieved a revisable torsional stroke of 46°/mm with peak rotational speed of up to 10,000 rpm. We measured a gravimetric torque of up to 28.5 N•m/kg which is higher than the 3 - 6 N•m/kg for direct-drive commercial electric motors. These remarkable performance results are comparable to those of guest-infiltrated carbon nanotube twisted yarns.

  1. Omental torsion in a captive polar bear (Ursus maritimus).

    Science.gov (United States)

    Mendez-Angulo, Jose L; Funes, Francisco J; Trent, Ava M; Willette, Michelle; Woodhouse, Kerry; Renier, Anna C

    2014-03-01

    This is the first case report of an omental torsion in a polar bear (Ursus maritimus). A captive, 23-yr-old, 250-kg, intact female polar bear presented to the University of Minnesota Veterinary Medical Center with a 2-day history of lethargy, depression, and vomiting. Abdominal ultrasound identified large amounts of hyperechoic free peritoneal fluid. Ultrasound-guided abdominocentesis was performed and yielded thick serosanguinous fluid compatible with a hemoabdomen. An exploratory laparotomy revealed a large amount of malodorous, serosanguineous fluid and multiple necrotic blood clots associated with a torsion of the greater omentum and rupture of a branch of the omental artery. A partial omentectomy was performed to remove the necrotic tissue and the abdomen was copiously lavaged. The polar bear recovered successfully and is reported to be clinically well 6 mo later. This condition should be considered as a differential in bears with clinical signs of intestinal obstruction and hemoabdomen.

  2. TORSIONAL DEFORMATION AND FATIGUE BEHAVIOUR OF 6061 ALUMINIUM ALLOY

    Directory of Open Access Journals (Sweden)

    marini marno

    2012-02-01

    Full Text Available Torsional deformation and fatigue behaviour of both solid and thin-walled tubular specimens were made from as-received and heat treated 6061 aluminium alloy were studied. 6061 aluminium alloy have been widely used as a candidate material in automobile, aerospace, aircraft and structural application because of their superior mechanical properties such as high strength to weight ratio, good ductility and others. The differences in cyclic deformation and fatigue behaviours between round and solid specimens where a stress gradient exist, and thin-walled tubular specimens where a uniform stress state is commonly assumed, are also discussed. Von Mises and Tresca criteria has been used to predict the monotonic and cyclic deformation curve and compared to the torsional data obtained from the experiment. The S-N curve was used to present and evaluate the fatigue life of the specimens. Through fractographic analysis, failure criteria of fracture surfaces were observed and discussed. 

  3. Structural plasticity of single chromatin fibers revealed by torsional manipulation

    CERN Document Server

    Bancaud, Aurelien; Barbi, Maria; Wagner, Gaudeline; Allemand, Jean-Francois; Mozziconacci, Julien; Lavelle, Christophe; Croquette, Vincent; Victor, Jean-Marc; Prunell, Ariel; Viovy, Jean-Louis

    2006-01-01

    Magnetic tweezers are used to study the mechanical response under torsion of single nucleosome arrays reconstituted on tandem repeats of 5S positioning sequences. Regular arrays are extremely resilient and can reversibly accommodate a large amount of supercoiling without much change in length. This behavior is quantitatively described by a molecular model of the chromatin 3-D architecture. In this model, we assume the existence of a dynamic equilibrium between three conformations of the nucleosome, which are determined by the crossing status of the entry/exit DNAs (positive, null or negative). Torsional strain, in displacing that equilibrium, extensively reorganizes the fiber architecture. The model explains a number of long-standing topological questions regarding DNA in chromatin, and may provide the ground to better understand the dynamic binding of most chromatin-associated proteins.

  4. On Polya's inequality for torsional rigidity and first Dirichlet eigenvalue

    OpenAIRE

    Berg, M. van den; Ferone, V.; Nitsch, C.; Trombetti, C.

    2016-01-01

    Let $\\Omega$ be an open set in Euclidean space with finite Lebesgue measure $|\\Omega|$. We obtain some properties of the set function $F:\\Omega\\mapsto \\R^+$ defined by $$ F(\\Omega)=\\frac{T(\\Omega)\\lambda_1(\\Omega)}{|\\Omega|} ,$$ where $T(\\Omega)$ and $\\lambda_1(\\Omega)$ are the torsional rigidity and the first eigenvalue of the Dirichlet Laplacian respectively. We improve the classical P\\'olya bound $F(\\Omega)\\le 1,$ and show that $$F(\\Omega)\\le 1- \

  5. The Attenuation of Torsional Strain Wave in a PMMA Rod

    OpenAIRE

    田辺, 裕治; 前川, 一郎; 半田, 晋一; 原, 利昭; Tanabe, Yuji; Maekawa, Ichiro; Handa, Shinichi; Hara, Toshiaki

    1990-01-01

    In order to clarify the strain attenuation during shear wave propagation, impact torsion experiments are carried out using a PMMA rod specimen. The strain pulses measured by strain gages are complicated due to the superposition of many reflected and transmitted waves from the supported end of the specimen. To obtain data from such pulses for determining a viscoelastic model, a method which modifies the pulse form is developed taking into account wave propagation behavior in the experimental s...

  6. Effect of Axial Torsion on sp Carbon Atomic Wires

    OpenAIRE

    Ravagnan, L.; Manini, N.; Cinquanta, E.; Onida, G.; Motta, C.; Sangalli, D.; Bordoni, A; Devetta, M.; Piseri, P.; Milani, P.

    2009-01-01

    Ab-initio calculations within Density Functional Theory combined with experimental Raman spectra on cluster-beam deposited pure carbon films provide a consistent picture of sp-carbon chains stabilized by sp^3 or sp^2 terminations, the latter being sensitive to torsional strain. This unexplored effect promises many exciting applications since it allows one to modify the conductive states near the Fermi level and to switch on and off the on-chain pi-electron magnetism.

  7. Effect of axial torsion on sp carbon atomic wires.

    Science.gov (United States)

    Ravagnan, Luca; Manini, Nicola; Cinquanta, Eugenio; Onida, Giovanni; Sangalli, Davide; Motta, Carlo; Devetta, Michele; Bordoni, Andrea; Piseri, Paolo; Milani, Paolo

    2009-06-19

    Ab initio calculations within density-functional theory combined with experimental Raman spectra on cluster-beam deposited pure-carbon films provide a consistent picture of sp-carbon chains stabilized by sp;{3} or sp;{2} terminations, the latter being sensitive to torsional strain. This unexplored effect promises many exciting applications since it allows one to modify the conductive states near the Fermi level and to switch on and off the on-chain pi-electron magnetism.

  8. Metatarsal torsion in monkeys, apes, humans and australopiths.

    Science.gov (United States)

    Drapeau, Michelle S M; Harmon, Elizabeth H

    2013-01-01

    This paper presents an analysis of metatarsal torsion in apes, cercopithecoids and humans, compares australopiths with these species, and discusses their inferred foot morphology and function relative to prehensility, arboreality and the presence or absence of a longitudinal arch. Our results show that locomotor modes are reflected in metatarsal torsion values. Apes, which climb vertically with their foot inverted, have hallucal metatarsal heads that are turned toward the other toes and lateral toes that are inverted. Cercopithecoids, which tend to orient their feet in an axis more parallel to the line of motion, present signs of prehensility by having inverted 2nd metatarsals that oppose the hallux, while their two lateral-most metatarsals are strongly everted. Humans, with their rigid feet and longitudinal arches, have all toes that present their plantar surface toward the ground, resulting in hallucal and 2nd metatarsals that are relatively untwisted and the others that are strongly everted. Humans are different from all taxa only for the 2nd and 3rd metatarsal. It is hypothesized that the untwisted 2nd metatarsal reflects the lack of digit opposability of the medial foot and the strongly everted 3rd metatarsal reflects the longitudinal arch. Australopithecus afarensis was characterized by an everted lateral foot, the prerequisite for the development, but not necessarily an indicator, of a longitudinal arch. In Australopithecus africanus, torsion of fragmentary and complete 1st, 2nd, 3rd and 5th metatarsals suggest that the species did not have a foot with monkey- or ape-like prehensile capabilities and did not have a human-like longitudinal arch. In the Swartkrans remains, torsion is consistent with an unprehensile foot. The morphology of the fossils indicates that there was strong selection to orient the plantar surface of the toes facing the ground at the expense of a grasping foot and inversion ability. Copyright © 2012 Elsevier Ltd. All rights reserved.

  9. A measurement of G with a cryogenic torsion pendulum.

    Science.gov (United States)

    Newman, Riley; Bantel, Michael; Berg, Eric; Cross, William

    2014-10-13

    A measurement of Newton's gravitational constant G has been made with a cryogenic torsion pendulum operating below 4 K in a dynamic mode in which G is determined from the change in torsional period when a field source mass is moved between two orientations. The source mass was a pair of copper rings that produced an extremely uniform gravitational field gradient, whereas the pendulum was a thin fused silica plate, a combination that minimized the measurement's sensitivity to error in pendulum placement. The measurement was made using an as-drawn CuBe torsion fibre, a heat-treated CuBe fibre, and an as-drawn Al5056 fibre. The pendulum operated with a set of different large torsional amplitudes. The three fibres yielded high Q-values: 82 000, 120 000 and 164 000, minimizing experimental bias from fibre anelasticity. G-values found with the three fibres are, respectively: {6.67435(10),6.67408(15),6.67455(13)}×10(-11) m(3) kg(-1) s(-2), with corresponding uncertainties 14, 22 and 20 ppm. Relative to the CODATA2010 G-value, these are higher by 77, 37 and 107 ppm, respectively. The unweighted average of the three G-values, with the unweighted average of their uncertainties, is 6.67433(13)×10(-11) m(3) kg(-1) s(-2) (19 ppm). © 2014 The Author(s) Published by the Royal Society. All rights reserved.

  10. Microstructural White Matter Changes in Primary Torsion Dystonia

    OpenAIRE

    Carbon, Maren; Kingsley, Peter B.; Tang, Chengke; Bressman, Susan; Eidelberg, David

    2008-01-01

    Primary torsion dystonia (PTD) has been conceptualized as a disorder of the basal ganglia. However, recent data suggest a widespread pathology involving motor control pathways. In this report, we explored whether PTD is associated with abnormal anatomical connectivity within motor control pathways. We used diffusion tensor magnetic resonance imaging (DT-MRI) to assess the microstructure of white matter. We found that fractional anisotropy, a measure of axonal integrity and coherence, was sign...

  11. Quantitative software analysis of ultrasonographic textures in experimental testicular torsion.

    Science.gov (United States)

    Aslan, Mustafa; Kucukaslan, Ibrahim; Mulazimoglu, Serkan; Soyer, Tutku; Şenyücel, Mine; Çakmak, Murat; Scholbach, Jakob; Aslan, Selim

    2013-04-01

    Ultrasonography (US) has high diagnostic value in testicular torsion but is vulnerable to several potential errors, especially in the early period. Echotexture (ETX) analysis software provides a numerical expression of B-mode images and allows quantitative evaluation of blood flow due to ischemic damage using power Doppler US (PDUS) analysis. Our aim in this study was to determine the diagnostic value and effective parameters of EXT analysis software in the early period of torsion using B-mode and PDUS images. In this study, eight rats were used. Following anesthesia, the right testis was rotated to a 1080-degree counterclockwise position whereas the left testis was left in place to have a control group. B-mode and PDUS images of both sides were recorded with a portable US device immediately (0 hour) and 1 and 2 hours after torsion. The B-mode images were analyzed in terms of gradient, homogeneity, and contrast using the BS200pro software (BAB Digital Imaging System 2007, Ankara, Turkey). Intensity (I)-red and area (A)-red values were measured on PDUS images with the Pixelflux (Version 1.0, Chameleon-Software, Leipzig, Germany). The data were evaluated by the Mann-Whitney U and Wilcoxon tests. Data from B-mode US image EXT analysis showed no significant difference between the right and left testicles in 0 to 2 hours (p > 0.05). The values obtained from PDUS analysis (I-red and A-red) significantly decreased at the testicular torsion side at the end of the second hour (p 0.05) whereas the flow was significantly lower at 2 hours (p analysis. Georg Thieme Verlag KG Stuttgart · New York.

  12. Impact of intelligent phacoemulsification software on torsional phacoemulsification surgery

    OpenAIRE

    Canturk Ugurbas S; Caliskan S; Alpay A; Ugurbas SH

    2012-01-01

    Silay Canturk Ugurbas, Sinan Caliskan, Atilla Alpay, Suat Hayri UgurbasDepartment of Ophthalmology, Bulent Ecevit University School of Medicine, Zonguldak, TurkeyBackground: The purpose of this study was to compare phacoemulsification energy parameters during torsional phacoemulsification with or without the use of intelligent phacoemulsification (IP) software.Methods: One hundred and twenty-eight eyes with nuclear grades ranging from 1 to 5 were enrolled in this randomized prospective study....

  13. Calculation of characteristics of torsionally vibrating mechatronic system

    OpenAIRE

    A. Buchacz

    2007-01-01

    Purpose: of this paper is the application of the approximate method to solve the task of assigning the frequencymodalanalysis and characteristics of a mechatronic system.Design/methodology/approach: was the formulated and solved as a problem in the form of a set of differentialequations of motion and state equations of the considered mechatronic model of an object. To obtain thesolution, Galerkin’s method was used. The discussed torsionally vibrating mechanical system is a continuousbar of ci...

  14. Elasto-plastic torsion problem as an infinity Laplace's equation

    Directory of Open Access Journals (Sweden)

    Ahmed Addou

    2006-12-01

    Full Text Available In this paper, we study a perturbed infinity Laplace's equation, the perturbation corresponds to an Leray-Lions operator with no coercivity assumption. We consider the case where data are distributions or $L^{1}$ elements. We show that this problem has an unique solution which is the solution to the variational inequality arising in the elasto-plastic torsion problem, associated with an operator $A$.

  15. Factors affecting pediatric patient transfer in testicular torsion.

    Science.gov (United States)

    Lodwick, Daniel L; Cooper, Jennifer N; Minneci, Peter C; Deans, Katherine J; McLeod, Daryl

    2016-06-01

    Testicular torsion is a surgical emergency, and interhospital transfer could delay care and increase the risk of orchiectomy. This study identifies factors associated with transfer for pediatric testicular torsion. This retrospective cross-sectional study examined emergency department (ED) visits for testicular torsion by men aged 1-21 y in National Emergency Department Sample from 2006 to 2012. Freestanding children's hospitals were excluded. Analyses were weighted to produce nationally representative estimates. Patient- and institutional-level predictors of transfer were evaluated using Rao-Scott chi-square tests and multivariable logistic regression. There were 11,435 ED visits for testicular torsion resulting in admission or transfer. In multivariable regression, the probability of transfer decreased with increasing age but remained higher for patients aged 15-17 y than for those aged 18-21 y (odds ratio [OR] = 1.51, P patients living in zip codes in the highest income quartile (OR = 0.69 versus lowest, P = 0.003) or with listed comorbidities (OR = 0.55, P Transfer was less likely in the Northeast (OR = 0.28 versus Midwest, P Transfer was less common with increasing annual pediatric ED volume (OR = 0.95 per 1000 patients, P Transfer rates increased significantly over the study period (23.6%-38.8%, P transferred than young adults. Interhospital transfers in these patients may represent a potential target for improving care. Future work should focus on evaluating the effect of transfer on the risk for undergoing orchiectomy. Copyright © 2016 Elsevier Inc. All rights reserved.

  16. Torsion of a wandering spleen: a case report.

    Science.gov (United States)

    Kaabar, Néjib; Ben Abdallah, Rabiaa; Yengui, Houssem; Hellal, Youssef; Ben Malek, Riadh; Bouthour, Habib; Sayed, Sadok

    2014-04-01

    Wandering spleen is a rare entity in child. It is generated by laxity or failure of development of spleen ligaments causing the migration of the spleen from its normal anatomical site to another abdominal or pelvic location. It can be congenital or acquired. The most dangerous complication is the occurrence of torsion of the spleen around its pedicle. aim: Report of a new observation and present the diagnostic, treatment and outcome aspects of torsion of ectopic spleen. We report the case of a 17 years old girl who was admitted for an acute abdomen pain and fever. Clinical examination revealed generalized abdominal defence and an under umbilical mass which was very painful on palpation. Ultrasound and CT scans have visualized the pelvic mass, which measured four inches long axis. The spleen wasn't on its normal seat. The patient was operated urgently. Surgical exploration showed that the mass corresponded to a wandering spleen in pelvic position, necrotic and twisted around its pedicle. A splenectomy was performed with simple sequences. torsion of the wandering spleen can progress to total necrosis of the spleen mass. This complication is feared in any ectopic and painful spleen.

  17. Diesel engine torsional vibration control coupling with speed control system

    Science.gov (United States)

    Guo, Yibin; Li, Wanyou; Yu, Shuwen; Han, Xiao; Yuan, Yunbo; Wang, Zhipeng; Ma, Xiuzhen

    2017-09-01

    The coupling problems between shafting torsional vibration and speed control system of diesel engine are very common. Neglecting the coupling problems sometimes lead to serious oscillation and vibration during the operation of engines. For example, during the propulsion shafting operation of a diesel engine, the oscillation of engine speed and the severe vibration of gear box occur which cause the engine is unable to operate. To find the cause of the malfunctions, a simulation model coupling the speed control system with the torsional vibration of deformable shafting is proposed and investigated. In the coupling model, the shafting is simplified to be a deformable one which consists of several inertias and shaft sections and with characteristics of torsional vibration. The results of instantaneous rotation speed from this proposed model agree with the test results very well and are successful in reflecting the real oscillation state of the engine operation. Furthermore, using the proposed model, the speed control parameters can be tuned up to predict the diesel engine a stable and safe running. The results from the tests on the diesel engine with a set of tuned control parameters are consistent with the simulation results very well.

  18. An ultrasonic piezoelectric motor utilizing axial-torsional coupling in a pretwisted non-circular cross-sectioned prismatic beam.

    Science.gov (United States)

    Wajchman, David; Liu, Kuang-Chen; Friend, James; Yeo, Leslie

    2008-04-01

    A rotary piezoelectric motor design with simple structural components and the potential for miniaturization using a pretwisted beam stator is demonstrated in this paper. The beam acts as a vibration converter to transform axial vibration input from a piezoelectric element into combined axial-torsional vibration. The axial vibration of the stator modulates the torsional friction forces transmitted to the rotor. Prototype stators measuring 6.5 x 6.5 x 67.5 mm were constructed using aluminum (2024-T6) twisted beams with rectangular cross-section and multilayer piezoelectric actuators. The stall torque and noload speed attained for a rectangular beam with an aspect ratio of 1.44 and pretwist helix angle of 17.7 degrees C were 0.17 mNm and 840 rpm with inputs of 184.4 kHz and 149 mW, respectively. Operation in both clockwise and counterclockwise directions was obtained by choosing either 70.37 or 184.4 kHz for the operating frequency. The effects of rotor preload and power input on motor performance were investigated experimentally. The results suggest that motor efficiency is higher at low power input, and that efficiency increases with preload to a maximum beyond which it begins to drop.

  19. Major Oil Plays in Utah and Vicinity

    Energy Technology Data Exchange (ETDEWEB)

    Thomas C. Chidsey; Craig D. Morgan; Kevin McClure; Douglas A. Sprinkel; Roger L. Bon; Hellmut H. Doelling

    2003-12-31

    fractured and sealed by overlying argillaceous and non-fractured units. The best outcrop analogs for Twin Creek reservoirs are found at Devils Slide and near the town of Peoa, Utah, where fractures in dense, homogeneous non-porous limestone beds are in contact with the basal siltstone units (containing sealed fractures) of the overlying units. The shallow marine, Mississippian Leadville Limestone is a major oil and gas reservoir in the Paradox Basin of Utah and Colorado. Hydrocarbons are produced from basement-involved, northwest-trending structural traps with closure on both anticlines and faults. Excellent outcrops of Leadville-equivalent rocks are found along the south flank of the Uinta Mountains, Utah. For example, like the Leadville, the Mississippian Madison Limestone contains zones of solution breccia, fractures, and facies variations. When combined with subsurface geological and production data, these outcrop analogs can improve (1) development drilling and production strategies such as horizontal drilling, (2) reservoir-simulation models, (3) reserve calculations, and (4) design and implementation of secondary/tertiary oil recovery programs and other best practices used in the oil fields of Utah and vicinity. In the southern Green River Formation play of the Uinta Basin, optimal drilling, development, and production practices consist of: (1) owning drilling rigs and frac holding tanks; (2) perforating sandstone beds with more than 8 percent neutron porosity and stimulate with separate fracture treatments; (3) placing completed wells on primary production using artificial lift; (4) converting wells relatively soon to secondary waterflooding maintaining reservoir pressure above the bubble point to maximize oil recovery; (5) developing waterflood units using an alternating injector--producer pattern on 40-acre (16-ha) spacing; and (6) recompleting producing wells by perforating all beds that are productive in the waterflood unit. As part of technology transfer

  20. At Right Angles

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 17; Issue 9. At Right Angles. Shailesh A Shirali. Information and Announcements Volume 17 Issue 9 September 2012 pp 920-920. Fulltext. Click here to view fulltext PDF. Permanent link: http://www.ias.ac.in/article/fulltext/reso/017/09/0920-0920 ...

  1. Application of a boundary element method to the study of dynamical torsion of beams

    Science.gov (United States)

    Czekajski, C.; Laroze, S.; Gay, D.

    1982-01-01

    During dynamic torsion of beam elements, consideration of nonuniform warping effects involves a more general technical formulation then that of Saint-Venant. Nonclassical torsion constants appear in addition to the well known torsional rigidity. The adaptation of the boundary integral element method to the calculation of these constants for general section shapes is described. The suitability of the formulation is investigated with some examples of thick as well as thin walled cross sections.

  2. Appendiceal torsion associated with undescended caecum: a case report and review of the literature

    Science.gov (United States)

    Dimitriadis, Panagiotis A; Makar, Ragai R; Randall, Jon K; Ramus, James

    2012-01-01

    Torsion of the vermiform appendix is a rare disorder that causes symptoms similar to those of acute appendicitis. Primary and secondary causes of appendiceal torsion have been reported in the literature. Laparoscopy appears to be the most appropriate modality for diagnosis and treatment where the condition is suspected. To our knowledge this is the first case of appendiceal torsion in an adult causing right upper quadrant pain related to caecal malposition. PMID:23010467

  3. Deep brain stimulation and neuromodulation for torsion dystonia

    Directory of Open Access Journals (Sweden)

    Jing WANG

    2015-10-01

    Full Text Available Objective To discuss the curative effect and safety of deep brain stimulation (DBS and neuromodulation in the treatment of patients with torsion dystonia. Methods Ten patients with torsion dystonia underwent subthalamic nucleus DBS (STN-DBS and 3 patients with torsion dystonia underwent globus pallidus internus DBS (GPi-DBS. Regulate the stimulus parameters, evaluate the improvement of torsion dystonia by using Burke-Fahn-Marsden Dystonia Rating Scale (BFMDRS and record related adverse events. Results Among the 13 patients, 6 patients were improved by over 60% in 1-3 d and 3 patients one week after stimulation, and the improvement rate was > 75% in 6 months and > 85% in one year. Two patients showed improvement 2 months after stimulation, and the improvement rate was > 60% in 6 months and > 80% in one year. One patient showed slight improvement immediately after operation, and the improvement rate increased to 45% in 6 months and 75% in one year. One patient removed the stimulator. No adverse event related to the operation was found in all 13 patients. The stimulus parameters for STN-DBS were voltage 1.50-2.00 V, frequency 130-145 Hz, pulse width 60-90 μs at 6 months postoperatively, and were voltage 2.00-2.50 V, frequency 130-150 Hz, pulse width 60-90 μs at one year postoperatively. The stimulus parameters for GPi-DBS were voltage 2.50-2.80 V, frequency 130-160 Hz, pulse width 60-90 μs at 6 months postoperatively, and were voltage 2.50-4.00 V, frequency 145-170 Hz, pulse width 60-90 μs at one year postoperatively. Conclusions Both STN-DBS and GPi-DBS have good curative effect and safety in the treatment for torsion dystonia. Besides, patients should be treated with individual neuromodulation. DOI: 10.3969/j.issn.1672-6731.2015.10.007

  4. Molecular Symmetry Analysis of Low-Energy Torsional and Vibrational States in the S_{0} and S_{1} States of p-XYLENE to Interpret the Rempi Spectrum

    Science.gov (United States)

    Groner, Peter; Gardner, Adrian M.; Tuttle, William Duncan; Wright, Timothy G.

    2017-06-01

    The electronic transition S_{1} ← S_{0} of p-xylene (pXyl) has been observed by REMPI spectroscopy. Its analysis required a detailed investigation of the molecular symmetry of pXyl whose methyl groups are almost free internal rotors. The molecular symmetry group of pXyl has 72 operators. This group, called [33]D_{2h}, is isomorphic to G_{36}(EM), the double group for ethane and dimethyl acetylene even though it is NOT a double group for pXyl. Loosely speaking, the group symbol, [33]D_{2h}, indicates that is for a molecule with two threefold rotors on a molecular frame with D_{2h} point group symmetry. The transformation properties of the (i) free internal rotor basis functions for the torsional coordinates, (ii) the asymmetric rotor (Wang) basis functions for the Eulerian angles, (iii) nuclear spin functions, (iv) potential function, and (v) transitions dipole moment functions were determined. The forms of the torsional potential in the S_{0} and S_{1} states and the dependence of the first order torsional splittings on the potential coefficients have been obtained. AM Gardner, WD Tuttle, P. Groner, TG Wright, J. Chem. Phys., submitted Dec 2016 P Groner, JR Durig, J. Chem. Phys., 66 (1977) 1856 PR Bunker, P Jensen, Molecular Symmetry and Spectroscopy (1998, NRC Research Press, Ottawa, 2nd ed.)

  5. Effect of screw position on single cycle to failure in bending and torsion of a locking plate-rod construct in a synthetic feline femoral gap model.

    Science.gov (United States)

    Niederhäuser, Simone K; Tepic, Slobodan; Weber, Urs T

    2015-05-01

    To evaluate the effect of screw position on strength and stiffness of a combination locking plate-rod construct in a synthetic feline femoral gap model. 30 synthetic long-bone models derived from beechwood and balsa wood. 3 constructs (2 locking plate-rod constructs and 1 locking plate construct; 10 specimens/construct) were tested in a diaphyseal bridge plating configuration by use of 4-point bending and torsion. Variables included screw position (near the fracture gap and far from the fracture gap) and application of an intramedullary pin. Constructs were tested to failure in each loading mode to determine strength and stiffness. Failure was defined as plastic deformation of the plate or breakage of the bone model or plate. Strength, yield angle, and stiffness were compared by use of a Wilcoxon test. Placement of screws near the fracture gap did not increase bending or torsional stiffness in the locking plate-rod constructs, assuming the plate was placed on the tension side of the bone. Addition of an intramedullary pin resulted in a significant increase in bending strength of the construct. Screw positioning did not have a significant effect on any torsion variables. Results of this study suggested that, in the investigated plate-rod construct, screw insertion adjacent to the fracture lacked mechanical advantages over screw insertion at the plate ends. For surgeons attempting to minimize soft tissue dissection, the decision to make additional incisions for screw placement should be considered with even more caution.

  6. Adnexal Torsion with Dystrophic Calcifications in an Adolescent: A Chronic Entity?

    Directory of Open Access Journals (Sweden)

    Pinar Solmaz Hasdemir

    2013-01-01

    Full Text Available Intermittent pelvic pain caused by ovarian cysts in adolescence may be due to torsion or partial torsion of the ovary. We present a case of 18-year old adolescent with symptomatic left ovarian torsion with calcifications demonstrated by pelvic MRI and ultrasonography prior to surgery. The pathologic investigation demonstrated dystrophic calcifications. We speculated that the pattern of the intermittent pain in the story of the patient and the dystrophic calcifications in pathologic investigation which is thought that it might have been potentially developed as a result of chronic hypoxia due to intermittent partial torsions over a period of two years.

  7. Torsional stress and resistance of concrte member. Concrete buzai no nejiri oryoku to tairyoku

    Energy Technology Data Exchange (ETDEWEB)

    Saeki, N. (Hokkaido University, Sapporo (Japan). Faculty of Engineering)

    1991-09-01

    Torsional stress and resistance are discussed for designing concrete members. A hypothesis was given that, in the simple torsion elasticity theory, the axial displacement is freely variable and no stress is created. In spherical and cylindrical cross section, no axial deformation will occur, but a displacement can occur in rectangular cross section. The general torsion elasticity theory can be applied also to a case where an axial stress is created. A discussion was also given to the plasticity theory in which shear stress enters the plastic region. A plain concrete is destructed at the same time as cracks develop, hence it reaches its resistance limit when the calculated value for a tensile stress caused from a torsional stress exceeds its tensile strength. Torsional resistance of a reinforced concrete after cracks have developed is calculated generally by the space truss theory, wherein the torsional load is thought shared in the lateral reinforcing bars, axial reinforcing bars, and diagonal concrete members. The pure torsion or torsion-pure bending resistance may be calculated theoretically, but the combined torsion-bending resistance is sought generally based on correlative curves derived from experiments. 25 refs., 14 figs., 2 tabs.

  8. Effect of Soil Structure Interaction on Torsional Response of Structure Supported by Asymmetric Soil Foundation System

    Directory of Open Access Journals (Sweden)

    Fangyuan Zhou

    2016-01-01

    Full Text Available The torsional response of a structure supported by asymmetric foundation was investigated in this study. Several types of the asymmetric soil foundation system were employed to analyze the effect of soil structure interaction on torsional response of the superstructure. It can be concluded from the study that torsional response would be generated for a structure supported by asymmetric soil foundation system under horizontal seismic excitation, and the generated torsional response of the superstructure changed with the degree of the asymmetry of the foundation.

  9. An induction motor model for high-frequency torsional vibration analysis

    Science.gov (United States)

    Widdle, R. D.; Krousgrill, C. M.; Sudhoff, S. D.

    2006-03-01

    High-frequency torsional oscillations of a 50 horsepower (hp) induction motor are investigated up to approximately 30 kHz. It is experimentally determined that torsional oscillations, due to the switching harmonics of the motor drive, contribute significantly to the torsional oscillation of the output shaft. Two torsional vibration models are developed. One model assumes the rotor to be rigid, while the other has a compliant rotor. The compliant model allows for greater transmission of high-frequency oscillations, and a better prediction of the measured output shaft vibration.

  10. Effect of Microstructure on Torsional Fatigue Endurance of Martensitic Carbon Steel

    National Research Council Canada - National Science Library

    TOYODA, Shunsuke; ISHIGURO, Yasuhide; KAWABATA, Yoshikazu; SAKATA, Kei; SATO, Akio; SAKAI, Jun'ichi

    2009-01-01

    The microstructural influence of martensitic carbon steel on torsional fatigue endurance was investigated, taking into consideration the application of high strength steel electric resistance welded (ERW...

  11. A combined experimental and theoretical study on realizing and using laser controlled torsion of molecules

    DEFF Research Database (Denmark)

    Madsen, Christian Bruun; Madsen, Lars Bojer; Viftrup, Simon

    2009-01-01

    It is demonstrated that strong laser pulses can introduce torsional motion in the axially chiral molecule 3,5-difluoro-3',5'-dibromobiphenyl. A nanosecond laser pulse spatially aligns the stereogenic carbon-carbon (C–C) bond axis allowing a perpendicularly polarized, intense femtosecond pulse...... to initiate torsional motion accompanied by a rotation about the fixed axis. We monitor the induced motion by femtosecond time-resolved Coulomb explosion imaging. Our theoretical analysis corroborates the experimental findings and on the basis of these results we discuss future applications of laser......-induced torsion, viz., time-resolved studies of deracemization and laser controlled molecular junctions based on molecules with torsion....

  12. Unusual cause of acute abdominal pain in a postmenopausal woman: adnexal torsion

    Directory of Open Access Journals (Sweden)

    Alper Biler

    2016-03-01

    Full Text Available Adnexal torsion is an infrequent but significant cause of acute lower abdominal pain in women. While adnexal torsion is generally considered in premenopausal women presenting with acute abdominal pain and a pelvic mass, it is a rare cause of acute abdominal pain during postmenopausal period. The diagnosis of adnexal torsion is often challenging due to nonspesific clinical, laboratory and physical examination findings. Causes of adnexal torsion is also different in premenopausal and postmenopausal women. While a simple functional cyst is often the cause of torsion in premenopausal women, it is more rarely the cause in postmenopausal women. Adnexal torsion is a surgical emergency. The surgery of adnexal torsion is performed either via conventional exploratory laparotomy or laparoscopic surgery. Adnexal torsion in postmenopausal women should be considered not only in the setting of sudden onset pain, but also in long-term abdominal discomfort. In this article, we presented a case with adnexal torsion that rarely cause acute abdominal pain in postmenopausal women. [Cukurova Med J 2016; 41(1.000: 167-170

  13. Tibial torsion in non-arthritic Indian adults: A computer tomography study of 100 limbs

    Directory of Open Access Journals (Sweden)

    Mullaji Arun

    2008-01-01

    Full Text Available Background: Knowledge of normal tibial torsion is mandatory during total knee replacement (TKR, deformity correction and fracture management of tibia. Different values of tibial torsion have been found in different races due to biological and mechanical factors. Value of normal tibial torsion in Indian limbs is not known, hence this study to determine the norm of tibial torsional value in normal Indian population. Materials and Methods: Computer tomography (CT scans were performed in 100 non-arthritic limbs of 50 Indian adults (42 males, eight females; age 26-40 years. Value of tibial torsion was measured using dorsal tangent to tibial condyles proximally and bimalleolar axis distally. Results: Normal tibial torsion was found to be 21.6 ± 7.6 (range 4.8 to 39.5 with none of the values in internal rotation. Right tibia was externally rotated by 2 degrees as compared to the left side ( P 0.029. No significant difference was found in male and female subjects. Value of tibial torsion was less than in Caucasian limbs, but was comparable to Japanese limbs when studies using similar measurement technique were compared. Conclusions: Indian limbs have less tibial torsion than Caucasian limbs but the value of tibial torsion is comparable to Japanese limbs.

  14. Pulsed-laser deposition of vicinal and c-axis oriented high temperature superconducting thin films

    CERN Document Server

    Rössler, R

    2000-01-01

    respect to the temperature, oxygen pressure and laser fluence. (Re,Hg)Ba sub 2 Ca sub ( n-1)Cu sub n O sub x films are synthesized on (001) and vicinal SrTiO sub 3 substrates in a two step process employing pulsed-laser deposition of Hg-free precursor films and Hg-vapour annealing in a sealed quartz tube. The sealed quartz tube technique is described in detail and the thermodynamics and the phase formation are discussed. The influence of the Hg-vapour pressure and the annealing temperature on the film properties are investigated. The influence of Hg-vapour annealing on Bi sub 2 Sr sub 2 CaCu sub 2 O sub x films is described. YBa sub 2 Cu sub 3 O sub x films with thicknesses 20 to 480 nm are deposited on vicinal SrTiO sub 3 substrates (10 degrees tilt angle). Variation of the resistivities and changes in the film morphology depending on film thickness are described. The influence of post-annealing treatments on the film properties is discussed. Pulsed-laser deposition (PLD) of high temperature superconducting ...

  15. Evaluation of the End Effect Impact on the Torsion Test for Determining the Shear Modulus of a Timber Beam through a Photogrammetry Approach

    OpenAIRE

    Gharavi, Niaz.; Zhang, Hexin.; Xie, Yanjun

    2017-01-01

    The timber beam end effect in the torsion test is evaluated using binocular stereo vision system. It is recommended by BS EN 408:2010+A1:2012 to exclude a distance of two to three times of cross-sectional thickness (b) from ends to avoid the end effect; whereas, this study indicates that this distance is not sufficiently far enough to remove this effect in slender cross-sections. The shear modulus of six timber beams with different aspect ratios is determined at the various angles and cross-s...

  16. Insertion angle of orthodontic mini-implants and their biomechanical performance: finite element analysis

    Directory of Open Access Journals (Sweden)

    Vinícius de Oliveira Rossi Arantes

    Full Text Available AbstractObjectiveThe aim of this study was to assess the stresses and strains generated after the application of two types of forces (traction of 200 gf and torsion of 20 N.cm in two types of orthodontic mini-implants inserted at different (45° and 90° to the cortical bone angles.Material and methodthree-dimensional models of two brands of mini-implant (SIN – Sao Paulo, Brazil, and RMO – South Korea were exported and analyzed by finite element analysis (FEA. Analyses were performed on simulations of cortical bone, cancellous bone and the screw.ResultFEA analysis showed that RMO mini-implants had greater elastic deformation when subjected to tensile and torsional forces when compared with SIN mini-implants. For both trademarks and insertion angles tested, there was greater cortical bone deformation, but with the greatest strain located on the mini-implant. Tension on the mini-implant was located in its transmucosal profile region.ConclusionWhen comparing the two brands of mini-implants by FEA, it is fair to conclude that that the larger number of threads and their greater angle of inclination resulted in less resistance to deformation and induced a higher level of tension in the mini-implant and cortical bone when subjected to forces, especially when inserted at an angle of 45º to the cortical bone.

  17. A Different Angle on Perspective

    Science.gov (United States)

    Frantz, Marc

    2012-01-01

    When a plane figure is photographed from different viewpoints, lengths and angles appear distorted. Hence it is often assumed that lengths, angles, protractors, and compasses have no place in projective geometry. Here we describe a sense in which certain angles are preserved by projective transformations. These angles can be constructed with…

  18. Surface-Step-Induced Double Magnetic Switching of Fe on Vicinal W(100)

    Energy Technology Data Exchange (ETDEWEB)

    Mireles, Hector C.; Erskine, J. L.

    2001-07-16

    Two-level magnetic switching of a bilayer epitaxial Fe film grown on a graded stepped W(100) surface is observed using the magneto-optic Kerr effect. Hysteresis loops produced by the film at a location on the curved W(100) surface corresponding to a vicinal angle of 6.4{sup o} exhibit two abrupt jumps in magnetization following spin orientation perpendicular to the steps resulting from surface-step-induced anisotropy. The two-step process can be understood in terms of abrupt depinning of spins in two inequivalent microdomains associated with the stepped surface. The results suggest a new realm of ultrathin film micromagnetics in which characteristic dimensions of 20--30{angstrom} can play a dominant role.

  19. Surface-step-induced double magnetic switching of Fe on vicinal W(100).

    Science.gov (United States)

    Mireles, H C; Erskine, J L

    2001-07-16

    Two-level magnetic switching of a bilayer epitaxial Fe film grown on a graded stepped W(100) surface is observed using the magneto-optic Kerr effect. Hysteresis loops produced by the film at a location on the curved W(100) surface corresponding to a vicinal angle of 6.4 degrees exhibit two abrupt jumps in magnetization following spin orientation perpendicular to the steps resulting from surface-step-induced anisotropy. The two-step process can be understood in terms of abrupt depinning of spins in two inequivalent microdomains associated with the stepped surface. The results suggest a new realm of ultrathin film micromagnetics in which characteristic dimensions of 20-30 A can play a dominant role.

  20. Small Angle Neutron Scattering

    Energy Technology Data Exchange (ETDEWEB)

    Urban, Volker S [ORNL

    2012-01-01

    Small Angle Neutron Scattering (SANS) probes structural details at the nanometer scale in a non-destructive way. This article gives an introduction to scientists who have no prior small-angle scattering knowledge, but who seek a technique that allows elucidating structural information in challenging situations that thwart approaches by other methods. SANS is applicable to a wide variety of materials including metals and alloys, ceramics, concrete, glasses, polymers, composites and biological materials. Isotope and magnetic interactions provide unique methods for labeling and contrast variation to highlight specific structural features of interest. In situ studies of a material s responses to temperature, pressure, shear, magnetic and electric fields, etc., are feasible as a result of the high penetrating power of neutrons. SANS provides statistical information on significant structural features averaged over the probed sample volume, and one can use SANS to quantify with high precision the structural details that are observed, for example, in electron microscopy. Neutron scattering is non-destructive; there is no need to cut specimens into thin sections, and neutrons penetrate deeply, providing information on the bulk material, free from surface effects. The basic principles of a SANS experiment are fairly simple, but the measurement, analysis and interpretation of small angle scattering data involves theoretical concepts that are unique to the technique and that are not widely known. This article includes a concise description of the basics, as well as practical know-how that is essential for a successful SANS experiment.

  1. [The functional sport shoe parameter "torsion" within running shoe research--a literature review].

    Science.gov (United States)

    Michel, F I; Kälin, X; Metzger, A; Westphal, K; Schweizer, F; Campe, S; Segesser, B

    2009-12-01

    Within the sport shoe area torsion is described as the twisting and decoupling of the rear-, mid- and forefoot along the longitudinal axis of the foot. Studies have shown that running shoes restrict the torsion of the foot and thus they increase the pronation of the foot. Based on the findings, it is recommended to design running shoes, which allow the natural freedom of movement of the foot. The market introduction of the first torsion concept through adidas(R) took place in 1989. Independently of the first market introduction, only one epidemiological study was conducted in the running shoe area. The study should investigate the occurrence of Achilles tendon problems of the athletes running in the new "adidas Torsion(R) shoes". However, further studies quantifying the optimal region of torsionability concerning the reduction of injury incidence are still missing. Newer studies reveal that the criterion torsion only plays a secondary roll regarding the buying decision. Moreover, athletes are not able to perceive torsionability as a discrete functional parameter. It is to register, that several workgroups are dealing intensively with the detailed analysis of the foot movement based on kinematic multi-segment-models. However, scientific as well as popular scientific contributions display that the original idea of the torsion concept is still not completely understood. Hence, the "inverse" characteristic is postulated. The present literature review leads to the deduction that the functional characteristics of the torsion concept are not fully implemented within the running shoe area. This implies the necessity of scientific studies, which investigate the relevance of a functional torsion concept regarding injury prevention based on basic and applied research. Besides, biomechanical studies should analyse systematically the mechanism and the effects of torsion relevant technologies and systems.

  2. A torsional MRE joint for a C-shaped robotic leg

    Science.gov (United States)

    Christie, M. D.; Sun, S. S.; Ning, D. H.; Du, H.; Zhang, S. W.; Li, W. H.

    2017-01-01

    Serving to improve stability and energy efficiency during locomotion, in nature, animals modulate their leg stiffness to adapt to their terrain. Now incorporated into many locomotive robot designs, such compliance control can enable disturbance rejection and improved transition between changing ground conditions. This paper presents a novel design of a variable stiffness leg utilizing a magnetorheological elastomer joint in a literal rolling spring loaded inverted pendulum (R-SLIP) morphology. Through the semi-active control of this hybrid permanent-magnet and coil design, variable stiffness is realized, offering a design which is capable of both softening and stiffening in an adaptive sort of way, with a maximum stiffness change of 48.0%. Experimental characterization first serves to assess the stiffness variation capacity of the torsional joint, and through later comparison with force testing of the leg, the linear stiffness is characterized with the R-SLIP-like behavior of the leg being demonstrated. Through the force relationships applied, a generalized relationship for determining linear stiffness based on joint rotation angle is also proposed, further aiding experimental validation.

  3. In-fiber torsion sensor based on dual polarized Mach-Zehnder interference.

    Science.gov (United States)

    Chen, Lei; Zhang, Wei-Gang; Wang, Li; Zhang, Hao; Sieg, Jonathan; Zhou, Quan; Zhang, Li-Yu; Wang, Biao; Yan, Tie-Yi

    2014-12-29

    This paper presents a novel optical fiber torsion sensor based on dual polarized Mach-Zehnder interference (DPMZI). Unlike the conventional fiber sensor, the proposed sensor is composed of a sensor part and a demodulator. The demodulator is made by a bared single mode fiber (SMF) loop, and the sensor part is a segment of a coated SMF placed before the loop. A mathematical model is proposed based on DPMZI mechanism and from the model when the sensor part is twisted, the E-field rotational angle will bring a quasi-linear impact on the resonance dip wavelength in their matched detecting range. A proof-of-concept experiment was performed to verify the theoretical prediction. From the experimental data, a sensitivity of -0.3703, -1.00962, and -0.59881 nm•m/rad is achieved with the determining range of 12.0936, 7.6959, and 10.4444 rad/m respectively. The sensor which is composed only of the SMF has the advantages of low insertion loss (~-2dB), healthy structure, low manufacture cost, and easy assembly and application.

  4. Torsional and Cyclic Fatigue Resistance of a New Nickel-Titanium Instrument Manufactured by Electrical Discharge Machining.

    Science.gov (United States)

    Pedullà, Eugenio; Lo Savio, Fabio; Boninelli, Simona; Plotino, Gianluca; Grande, Nicola M; La Rosa, Guido; Rapisarda, Ernesto

    2016-01-01

    The purpose of this study was to evaluate the torsional and cyclic fatigue resistance of the new Hyflex EDM OneFile (Coltene/Whaledent AG, Altstatten, Switzerland) manufactured by electrical discharge machining and compare the findings with the ones of Reciproc R25 (VDW, Munich, Germany) and WaveOne Primary (Dentsply Maillefer, Ballaigues, Switzerland). One hundred-twenty new Hyflex EDM OneFile (#25/0.08), Reciproc R25, and WaveOne Primary files were used. Torque and angle of rotation at failure of new instruments (n = 20) were measured according to ISO 3630-1 for each brand. Cyclic fatigue resistance was tested measuring the number of cycles to failure in an artificial stainless steel canal with a 60° angle and a 3-mm radius of curvature. Data were analyzed using the analysis of variance test and the Student-Newman-Keuls test for multiple comparisons. The fracture surface of each fragment was examined with a scanning electron microscope. The cyclic fatigue of Hyflex EDM was significantly higher than the one of Reciproc R25 and WaveOne Primary (P  .05). The new Hyflex EDM instruments (controlled memory wire) have higher cyclic fatigue resistance and angle of rotation to fracture but lower torque to failure than Reciproc R25 and WaveOne Primary files (M-wire for both files). Copyright © 2016 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  5. Ocular torsion responses to sinusoidal electrical vestibular stimulation.

    Science.gov (United States)

    Mackenzie, Stuart W; Reynolds, Raymond F

    2017-11-21

    Eye movements evoked by electrical vestibular stimulation (EVS) offer potential for diagnosing vestibular dysfunction. However, ocular recording techniques are often too invasive or impractical for routine clinical use. Furthermore, the kinematic nature of the EVS signal is not fully understood in terms of movement sensations. We apply sinusoidal EVS stimuli varying from 0.05 to 20Hz, and record the eye in darkness using an infrared camera. Eye movement was measured offline using commercially available software to track iris striations. Response gain and phase were calculated separately for eye position, velocity and acceleration across all frequencies, to determine how the brain interprets the EVS signal. Ocular torsion responses were observed at the same frequency as the stimulus, for all frequencies, while lateral/vertical responses were minimal or absent. Response gain and phase resembled previously reported responses to natural rotation, but only when analysing eye velocity, not position or acceleration. Our method offers a simple, affordable, reliable and non-invasive method for tracking the ocular response to EVS. It is more convenient than scleral coil recordings, or marking the sclera to aid video tracking. It also allows us to assess the torsional VOR at frequencies not possible with natural stimuli. Ocular torsion responses to EVS can be readily assessed using sinusoidal stimuli combined with an infrared camera. Gain and phase analysis suggests that the central nervous system interprets the stimulus as head roll velocity. Future work will assess the diagnostic potential for patients with vestibular disorders. Copyright © 2017 The Author(s). Published by Elsevier B.V. All rights reserved.

  6. The torsion of a wandering pelvic spleen: A case report.

    Science.gov (United States)

    Feroci, Francesco; Miranda, Egidio; Moraldi, Luca; Moretti, Renato

    2008-09-10

    A 15 years old patient was taken to the operative room for an explorative laparotomy due to abdominal pain and a pelvic spleen at preoperative computed tomography: was pointed out the absence of all splenic ligamentous attachments and short gastric vessels with a consequently dislocation of a bigger and congested spleen in the pelvis. This organ, wrapped in the omentum, was in a serious ischemic suffering due to a 720 degrees clock torsion around its exceptionally long pedicle (about 20 cm); besides was confirmed pancreatic body and tail ectopy. Following the derotation, the volume of the organ has decreased but became fixed in above norm dimensions. A total splenectomy was executed.

  7. Electromagnetic calibration system for sub-micronewton torsional thrust stand

    Science.gov (United States)

    Lam, J. K.; Koay, S. C.; Cheah, K. H.

    2017-12-01

    It is critical for a micropropulsion system to be evaluated. Thrust stands are widely recognised as the instrument to complete such tasks. This paper presents the development of an alternative electromagnetic calibration technique for thrust stands. Utilising the commercially made voice coils and permanent magnets, the proposed system is able to generate repeatable and also consistent steady-state calibration forces at over four orders of magnitude (30 – 23000 μN). The system is then used to calibrate a custom-designed torsional thrust stand, where its inherent ability in ease of setup is well demonstrated.

  8. Torsion bar antenna in the proper reference frame with rotation

    CERN Document Server

    Nakamura, Kouji

    2014-01-01

    The resultant response of the rotating torsion bar antenna for gravitational waves discussed in [M. Ando et al., Phys. Rev. Lett. {\\bf 105} (2010), 161101.] is re-investigate from a general-relativistic point of view. To do this, the equation of motion of a free falling particle in the proper reference frame of a rotating observer is used. As a result, the resultant response derived in the above paper is also valid even when $\\omega_{g}\\sim\\Omega$, where $\\omega_{g}$ and $\\Omega$ are the angular frequencies of gravitational waves and the rotation of the antenna, respectively.

  9. Relationship between the angle of repose and angle of internal ...

    African Journals Online (AJOL)

    Abstract. Click on the link to view the abstract. Keywords: Angle of repose, angle of internal friction, granular materials, triaxial compression machine, moisture content. Tanzania J. Agric. Sc. (1998) Vol.1 No.2, 187-194 ...

  10. Article Original Les torsions du cordon spermatique chez l'enfant

    African Journals Online (AJOL)

    mn

    ... (après corrections): 26/12/2009 d'une ischémie testiculaire par torsion du cordon spermatique constitue une hantise de tout chirurgien pédiatre devant une grosse bourse aigue de l'enfant. Dans notre pratique, les torsions du cor- don spermatique constituent une cause des grosses bourses douloureuses dont les carac- ...

  11. Should Torsion Balance Technique Continue to be Taught to Pharmacy Students?

    Science.gov (United States)

    Bilger, Rhonda; Chereson, Rasma

    2017-01-01

    Objective. To determine the types of balances used in compounding pharmacies: torsion or digital. Methods. A survey was mailed to the pharmacist-in-charge at 698 pharmacies, representing 47% of the pharmacies in Missouri as of July 2013. The pharmacies were randomly selected and stratified by region into eight regions to ensure a representative sample. Information was gathered regarding the type and use of balances and pharmacists’ perspectives on the need to teach torsion balance technique to pharmacy students. Results. The response rate for the survey was 53.3%. Out of the total responses received, those pharmacies having a torsion balance, digital balance or both were 46.8%, 27.4% and 11.8%, respectively. About 68.3% of respondents compound prescriptions. The study showed that 52% of compounding pharmacies use torsion balances in their practice. Of those with a balance in their pharmacy, 65.6% favored continuation of torsion balance instruction. Conclusions. Digital balances have become increasingly popular and have replaced torsion balances in some pharmacies, especially those that compound a significant number of prescriptions. The results of this study indicate that torsion balances remain integral to compounding practice. Therefore, students should continue being taught torsion balance technique at the college. PMID:28720913

  12. Nonspecificity of the rim sign in the scintigraphic diagnosis of missed testicular torsion

    Energy Technology Data Exchange (ETDEWEB)

    Vieras, F.; Kuhn, C.R.

    1983-02-01

    Causes of a hyperemic peritesticular rim on dynamic and static scintigrams are reviewed. Of 6 patients exhibiting such a pattern, 3 had missed testicular torsion; the other 3 had tumor, trauma, or inflamation. The authors conclude that a hyperemic peritesticular rim is a nonspecific finding reflecting underlying pathophysiological changes and is not pathognomonic of missed torsion.

  13. Should Torsion Balance Technique Continue to be Taught to Pharmacy Students?

    Science.gov (United States)

    Bilger, Rhonda; Chereson, Rasma; Salama, Noha Nabil

    2017-06-01

    Objective. To determine the types of balances used in compounding pharmacies: torsion or digital. Methods. A survey was mailed to the pharmacist-in-charge at 698 pharmacies, representing 47% of the pharmacies in Missouri as of July 2013. The pharmacies were randomly selected and stratified by region into eight regions to ensure a representative sample. Information was gathered regarding the type and use of balances and pharmacists' perspectives on the need to teach torsion balance technique to pharmacy students. Results. The response rate for the survey was 53.3%. Out of the total responses received, those pharmacies having a torsion balance, digital balance or both were 46.8%, 27.4% and 11.8%, respectively. About 68.3% of respondents compound prescriptions. The study showed that 52% of compounding pharmacies use torsion balances in their practice. Of those with a balance in their pharmacy, 65.6% favored continuation of torsion balance instruction. Conclusions. Digital balances have become increasingly popular and have replaced torsion balances in some pharmacies, especially those that compound a significant number of prescriptions. The results of this study indicate that torsion balances remain integral to compounding practice. Therefore, students should continue being taught torsion balance technique at the college.

  14. Ruptured Ectopic Pregnancy with Contralateral Ovarian Serous Cyst Adenoma Torsion: Laparoscopic Management of Double Trouble.

    Science.gov (United States)

    Ganesh, Deepa; Rajkumar, Anirudh; Rajkumar, J S; Guru, Venkatesan

    2016-01-01

    Adnexal torsion is responsible for 2.7% of all gynecological emergencies. Ectopic pregnancy is relatively common, occurring in 2% of all pregnancies. We report the second case of ruptured right tubal ectopic gestation with torsion of serous cystadenoma of left ovary. This was diagnosed after emergency laparoscopy done for acute abdomen. Right salpingectomy and left ovarian detorsion followed by cystectomy were done laparoscopically.

  15. Aerodynamic stability of long span suspension bridges with low torsional natural frequencies

    DEFF Research Database (Denmark)

    Andersen, Michael Styrk; Johansson, Jens; Brandt, Anders

    2016-01-01

    Classical flutter of suspended bridge decks can be avoided if the torsional frequencies are lower than the vertical. Wind tunnel tests of single boxes and twin box section models with torsional natural frequencies above and below the vertical frequency has been conducted. Flutter was avoided in a...

  16. Linear and Non Linear Effects on the Newtonian Gravitational Constant as deduced from the Torsion Balance

    OpenAIRE

    Rossi, Michele; Zaninetti, Lorenzo

    2008-01-01

    The Newtonian gravitational constant has still 150 parts per million of uncertainty. This paper examines the linear and nonlinear equations governing the rotational dynamics of the torsion gravitational balance. A nonlinear effect modifying the oscillation period of the torsion gravitational balance is carefully explored.

  17. Open string fluctuations in AdS space with and without torsion

    DEFF Research Database (Denmark)

    Larsen, A.L.; Lomholt, Michael Andersen

    2003-01-01

    The equations of motion and boundary conditions for the fluctuations around a classical open string, in a curved space-time with torsion, are considered in compact and world-sheet covariant form. The rigidly rotating open strings in anti-de Sitter space with and without torsion are investigated...

  18. Unsteady flow due to a disk executing non-torsional oscillation and ...

    Indian Academy of Sciences (India)

    This paper is concerned with the unsteady flow of a disk performing non-torsional oscillation in its own plane and a Newtonian fluid at infinity while they are initially rotating with the same angular velocity about non-coaxial axes. For a more general study, it is considered that the disk executes non-torsional oscillation along ...

  19. Management of Testicular torsion in Mulago Hospital over a 5-year ...

    African Journals Online (AJOL)

    A retrospective study of patients seen in Mulago Hospital with a clinical diagnosis of testicular torsion between 1993 and 1997 inclusive was undertaken. There were a total of 102 cases of torsion of the testis. Their ages ranged between 16 and 20 years. Over 50% of the patients reported to the hospital more than 48 hours ...

  20. Uterine Torsion in a West African Dwarf Ewe in Ibadan, Nigeria ...

    African Journals Online (AJOL)

    Keywords: Uterine torsion, West African Dwarf Ewe, Ibadan A case of uterine torsion in a 21/2 year old pluriparous West Africa Dwarf (WAD) ewe raised semi intensively with adequate veterinary care before the death of the dam and the lamb is presented. The dam had been off feed for 3 days and was found straining a night ...

  1. Management of Testicular torsion in Mulago Hospital over a 5-year ...

    African Journals Online (AJOL)

    Management of Testicular torsion in Mulago Hospital over a 5-year period. Ibingira C B R. hI hled (Surg). 1-ecturer in Anatom!; Makerere University hfedical School. P O Box 7072, Itorsion, and management. A retrospective study of patients seen in. Mulago Hospital with a ...

  2. Assessment of radial torsion using computed tomography in dogs with and without antebrachial limb deformity.

    Science.gov (United States)

    Kroner, Kevin; Cooley, Katie; Hoey, Seamus; Hetzel, Scott J; Bleedorn, Jason A

    2017-01-01

    To evaluate the reliability of radial torsion assessment in dogs using computed tomography (CT). Cadaveric and retrospective observational clinical study. Thoracic limbs (n = 40) from bilateral normal cadaveric canine specimens (10 pairs) and unilateral antebrachial angular limb deformity (ALD) dogs (10 uniapical and 10 biapical deformities). Limbs were evaluated using CT. Frontal, sagittal, and axial plane (torsion) values were obtained using published guidelines and compared between groups and limbs. Radial torsion reliability was assessed among 3 observers using intraclass correlation coefficients (ICC). The mean (±SD) radial torsion of normal dogs was 3.6° ± 6.4° and contained a significant right to left limb variation of 2.6°. Mean radial torsion in uniapical ALD limbs (3.6° ± 18.7°) was not significantly different from biapical ALD limbs (8.9° ± 17.9°). There was a wide range of torsion values in normal and ALD limbs. The interobserver reliability was excellent (ICC > 0.8) for normal dogs, good (0.73) for uniapical, and excellent (0.89) for biapical ALD limbs. The intraobserver reliability was excellent (>0.8) for all groups. There was a small side-to-side variation of radial torsion in normal dogs. With directed training, torsion assessment using CT is reliable in dogs with and without antebrachial bone deformity. © 2016 The American College of Veterinary Surgeons.

  3. Bathymetry of the Republic of the Marshall Islands and vicinity

    Science.gov (United States)

    Hein, James R.; Wong, Florence L.; Mosier, Dan L.

    1999-01-01

    The bathymetric map of the Republic of the Marshall Islands and vicinity is bounded by a window of latitude 3 to 17 degrees North, longitude 153 to 175 degrees East. The map was compiled from surveys conducted by the USGS, Korean Ocean Research and Development Institute, and published gridded data. In addition to national jurisdictions, island and atoll coastlines are indicated on the map.

  4. Chemo- and Regioselective Oxidation of Secondary Alcohols in Vicinal Diols

    NARCIS (Netherlands)

    Eisink, Niek; Minnaard, Adriaan; Witte, Martin

    Oxidation of secondary hydroxyl groups in vicinal diols enables the straightforward functionalization of biomolecules and biomaterials. The resulting hydroxy ketone can for example be used to form derivatives, such as the epimeric alcohol and imines, and it may be employed for chemical probe

  5. Landsat - SRTM Shaded Relief Comparison, Los Angeles and Vicinity

    Science.gov (United States)

    2002-01-01

    Digital elevation models (DEMs), such as those produced by the Shuttle Radar Topography Mission (SRTM), allow user-controlled visualization of the Earth's landforms that is not possible using satellite imagery alone. This three-view comparison shows Los Angeles, Calif., and vicinity, with a Landsat image (only) on the left, a shaded relief rendering of the SRTM DEM on the right, and a merge of the two data sets in the middle. Note that topographic expression in the Landsat image alone is very subtle due to the fairly high sun angle (63 degrees above the horizon) during the satellite overflight in late morning of a mid-Spring day (May 4, 2001). In contrast, computer generated topographic shading of the DEM provides a pure and bold image of topographic expression with a user specified illumination direction. The middle image shows how combining the Landsat and DEM shaded relief can result in a topographically enhanced satellite image in which the information content of both data sets is merged into a single view.Landsat has been providing visible and infrared views of the Earth since 1972. SRTM elevation data matches the 30-meter (98-foot) resolution of most Landsat images and helps in analyzing the large and growing Landsat image archive, managed by the U.S. Geological Survey (USGS).Elevation data used in this image was acquired by the Shuttle Radar Topography Mission (SRTM) aboard the Space Shuttle Endeavour, launched on Feb. 11, 2000. SRTM used the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) that flew twice on the Space Shuttle Endeavour in 1994. SRTM was designed to collect 3-D measurements of the Earth's surface. To collect the 3-D data, engineers added a 60-meter (approximately 200-foot) mast, installed additional C-band and X-band antennas, and improved tracking and navigation devices. The mission is a cooperative project between NASA, the National Imagery and Mapping Agency (NIMA) of the U

  6. Normal left ventricular torsion mechanics in healthy children: age related changes of torsion parameters are closely related to changes in heart rate.

    Science.gov (United States)

    Kim, Hye Jin; Yoon, Ji-Hong; Lee, Eun-Jung; Oh, Jin Hee; Lee, Jae Young; Lee, Soon Ju; Han, Ji Whan

    2015-03-01

    This study was aimed at assessing left ventricular torsion (LVtor) mechanics using speckle tracking echocardiography (STE), establishing normal reference values of principal LVtor parameters, and analyzing the age-related changes in normal children. Eighty children (aged 3 months to 15 years) with normal cardiac function and rhythm were recruited. LVtor parameters including rotations, twist and untwist, torsion, and their rate indices were measured using STE. Age and heart rate related changes of the parameters were analyzed. Speckle tracking echocardiography analyses for LVtor parameters had excellent reliability in 64 of 80 subjects (80%) (intraclass correlation coefficients; 0.93-0.97). Early systolic twist (EST) motions (-8.4--0.1°) were observed in all subjects during an early 20±7% of systolic time intervals. The peak systolic twist and torsion were 17.0±6.5° and 2.9±1.3°/cm, respectively. The peak twist velocity was recorded at 51±13% of systolic time and the peak untwist velocity at 13.8±11.5% of diastolic time intervals. Multivariate analysis showed that heart rate change was an independent predictor of changes in torsion parameters; significantly decreasing LV length-normalized apical and basal rotation, torsion, and twist and untwist rate with increasing age. Isovolumetric recoil rate was independent of change in age and heart rate. Left ventricle showed unique torsion mechanics in children with EST, torsion, and untwists. Heart rate was an independent predictor of the change in torsion parameters with aging.

  7. Complete acute gallbladder torsion diagnosed with abdominal ultrasonography and colour Doppler imaging.

    Science.gov (United States)

    Ohkura, Yu; Hashimoto, Masaji; Sasaki, Kazunari; Watanabe, Goro

    2013-03-14

    An 82-year-old woman was admitted to our hospital with a provisional diagnosis of acute cholecystitis. Abdominal ultrasonography and colour Doppler imaging played the most important role in confirming a diagnosis of gallbladder torsion preoperatively, and we decided to treat it laparoscopically. Operative findings showed that gallbladder was rotated 360° counterclockwise around the cystic duct and artery. This was a complete torsion of a gross type I wandering gallbladder. The patient had an uneventful postoperative course and was discharged. Laparoscopic cholecystectomy has recently been recommended for treating gallbladder torsion. Because the gallbladder is typically minimally adherent to the liver bed, cholecystectomy can be performed easily with minimal invasion. Gallbladder torsion is a relatively rare cause of an acute abdomen and is difficult to diagnose preoperatively, but we could diagnose complete, acute gallbladder torsion preoperatively with ultrasonography and colour Doppler imaging in this case, allowing for safe and completely curative laparoscopic cholecystectomy.

  8. Adnexal torsion in the first trimester of pregnancy: A case report

    Directory of Open Access Journals (Sweden)

    Mohammed Khairy Ali

    2013-12-01

    Full Text Available Adnexal torsion is a rare cause of acute abdominal pain during pregnancy. It is frequently associated with ovarian stimulation for in vitro fertilization (IVF or with ovarian masses, mainly of functional origin. It is uncommon for a normal-sized ovary to undergo torsion. Torsion of the ovary during pregnancy is common during third trimester. Adnexal torsion is rarely bilateral and is more common on the right side, perhaps because the sigmoid colon leaves a limited space for left adnexal mobility. Here we report a case of 23-year-old primigravida with 8 weeks pregnancy presented with sever left abdominal pain. Left abdominal tenderness was detected. Transabdominal ultrasound scan reported left adnexal torsion. Laparotomy and then left salpingo-oophorectomy were performed.

  9. Torsional diffusion Monte Carlo: A method for quantum simulations of proteins

    Science.gov (United States)

    Clary, David C.

    2001-06-01

    The quantum diffusion Monte Carlo (DMC) method is extended to the treatment of coupled torsional motions in proteins. A general algorithm and computer program has been developed by interfacing this torsional-DMC method with all-atom force-fields for proteins. The method gives the zero-point energy and atomic coordinates averaged over the coupled torsional motions in the quantum ground state of the protein. Application of the new algorithm is made to the proteins gelsolin (356 atoms and 142 torsions) and gp41-HIV (1101 atoms and 452 torsions). The results indicate that quantum-dynamical effects are important for the energies and geometries of typical proteins such as these.

  10. Scaling of misorientation angle distributions

    DEFF Research Database (Denmark)

    Hughes, D.A.; Chrzan, D.C.; Liu, Q.

    1998-01-01

    The measurement of misorientation angle distributions following different amounts of deformation in cold-rolled aluminum and nickel and compressed stainless steel is reported. The sealing of the dislocation cell boundary misorientation angle distributions is studied. Surprisingly, the distributions...

  11. Variable angle correlation spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Young Kyo [Univ. of California, Berkeley, CA (United States)

    1994-05-01

    In this dissertation, a novel nuclear magnetic resonance (NMR) technique, variable angle correlation spectroscopy (VACSY) is described and demonstrated with 13C nuclei in rapidly rotating samples. These experiments focus on one of the basic problems in solid state NMR: how to extract the wealth of information contained in the anisotropic component of the NMR signal while still maintaining spectral resolution. Analysis of the anisotropic spectral patterns from poly-crystalline systems reveal information concerning molecular structure and dynamics, yet in all but the simplest of systems, the overlap of spectral patterns from chemically distinct sites renders the spectral analysis difficult if not impossible. One solution to this problem is to perform multi-dimensional experiments where the high-resolution, isotropic spectrum in one dimension is correlated with the anisotropic spectral patterns in the other dimensions. The VACSY technique incorporates the angle between the spinner axis and the static magnetic field as an experimental parameter that may be incremented during the course of the experiment to help correlate the isotropic and anisotropic components of the spectrum. The two-dimensional version of the VACSY experiments is used to extract the chemical shift anisotropy tensor values from multi-site organic molecules, study molecular dynamics in the intermediate time regime, and to examine the ordering properties of partially oriented samples. The VACSY technique is then extended to three-dimensional experiments to study slow molecular reorientations in a multi-site polymer system.

  12. Angle performance on optima MDxt

    Energy Technology Data Exchange (ETDEWEB)

    David, Jonathan; Kamenitsa, Dennis [Axcelis Technologies, Inc., 108 Cherry Hill Dr, Beverly, MA 01915 (United States)

    2012-11-06

    Angle control on medium current implanters is important due to the high angle-sensitivity of typical medium current implants, such as halo implants. On the Optima MDxt, beam-to-wafer angles are controlled in both the horizontal and vertical directions. In the horizontal direction, the beam angle is measured through six narrow slits, and any angle adjustment is made by electrostatically steering the beam, while cross-wafer beam parallelism is adjusted by changing the focus of the electrostatic parallelizing lens (P-lens). In the vertical direction, the beam angle is measured through a high aspect ratio mask, and any angle adjustment is made by slightly tilting the wafer platen prior to implant. A variety of tests were run to measure the accuracy and repeatability of Optima MDxt's angle control. SIMS profiles of a high energy, channeling sensitive condition show both the cross-wafer angle uniformity, along with the small-angle resolution of the system. Angle repeatability was quantified by running a channeling sensitive implant as a regular monitor over a seven month period and measuring the sheet resistance-to-angle sensitivity. Even though crystal cut error was not controlled for in this case, when attributing all Rs variation to angle changes, the overall angle repeatability was measured as 0.16 Degree-Sign (1{sigma}). A separate angle repeatability test involved running a series of V-curves tests over a four month period using low crystal cut wafers selected from the same boule. The results of this test showed the angle repeatability to be <0.1 Degree-Sign (1{sigma}).

  13. Rat disc torsional mechanics: effect of lumbar and caudal levels and axial compression load.

    Science.gov (United States)

    Espinoza Orías, Alejandro A; Malhotra, Neil R; Elliott, Dawn M

    2009-03-01

    Rat models with altered loading are used to study disc degeneration and mechano-transduction. Given the prominent role of mechanics in disc function and degeneration, it is critical to measure mechanical behavior to evaluate changes after model interventions. Axial compression mechanics of the rat disc are representative of the human disc when normalized by geometry, and differences between the lumbar and caudal disc have been quantified in axial compression. No study has quantified rat disc torsional mechanics. Compare the torsional mechanical behavior of rat lumbar and caudal discs, determine the contribution of combined axial load on torsional mechanics, and compare the torsional properties of rat discs to human lumbar discs. Cadaveric biomechanical study. Cyclic torsion without compressive load followed by cyclic torsion with a fixed compressive load was applied to rat lumbar and caudal disc levels. The apparent torsional modulus was higher in the lumbar region than in the caudal region: 0.081+/-0.026 (MPa/degrees, mean+/-SD) for lumbar axially loaded; 0.066+/-0.028 for caudal axially loaded; 0.091+/-0.033 for lumbar in pure torsion; and 0.056+/-0.035 for caudal in pure torsion. These values were similar to human disc properties reported in the literature ranging from 0.024 to 0.21 MPa/degrees. Use of the caudal disc as a model may be appropriate if the mechanical focus is within the linear region of the loading regime. These results provide support for use of this animal model in basic science studies with respect to torsional mechanics.

  14. A new torsion pendulum for gravitational reference sensor technology development.

    Science.gov (United States)

    Ciani, Giacomo; Chilton, Andrew; Apple, Stephen; Olatunde, Taiwo; Aitken, Michael; Mueller, Guido; Conklin, John W

    2017-06-01

    We report on the design and sensitivity of a new torsion pendulum for measuring the performance of ultra-precise inertial sensors and for the development of associated technologies for space-based gravitational wave observatories and geodesy missions. The apparatus comprises a 1 m-long, 50 μm-diameter tungsten fiber that supports an inertial member inside a vacuum system. The inertial member is an aluminum crossbar with four hollow cubic test masses at each end. This structure converts the rotation of the torsion pendulum into translation of the test masses. Two test masses are enclosed in capacitive sensors which provide readout and actuation. These test masses are electrically insulated from the rest of the crossbar and their electrical charge is controlled by photoemission using fiber-coupled ultraviolet light emitting diodes. The capacitive readout measures the test mass displacement with a broadband sensitivity of 30 nm∕Hz and is complemented by a laser interferometer with a sensitivity of about 0.5 nm∕Hz. The performance of the pendulum, as determined by the measured residual torque noise and expressed in terms of equivalent force acting on a single test mass, is roughly 200 fN∕Hz around 2 mHz, which is about a factor of 20 above the thermal noise limit of the fiber.

  15. Isolated fallopian tube torsion: sonographic and CT features

    Energy Technology Data Exchange (ETDEWEB)

    Harmon, Jenna C.; Binkovitz, Larry A.; Binkovitz, Leah E. [Columbus Children' s Hospital, Department of Radiology, Columbus, OH (United States)

    2008-02-15

    Isolated fallopian tube torsion (IFTT) rarely occurs in pediatric patients and is difficult to diagnose preoperatively. To determine the common sonographic and CT findings in girls with IFTT. We retrospectively reviewed the hospital charts and imaging studies of the eight girls diagnosed with and treated for IFTT at Columbus Children's Hospital between January 1995 and June 2006 whose final diagnosis was IFTT. The mean age was 13 years with a range of 12 to 15 years. Two girls were premenarcheal. The most common presenting symptom was acute pelvic pain (n = 5). All patients were imaged. Six girls were imaged first with US, and the most common finding was a complex cystic pelvic mass in the midline (n = 5) and normal uterus and ovaries. Three of the eight girls had imaging with CT. In two girls, the torsed tube could be identified. In 63% of the girls, the uterus was deviated toward the side of torsion. The correct preoperative diagnosis was made in only one girl. None of the torsed fallopian tubes was salvaged at surgery. Pathological findings included ipsilateral adnexal cysts associated with the torsed tube (n = 7). IFTT should be considered in the differential diagnosis for perimenarcheal girls who present with acute pelvic pain and who demonstrate a cystic mass in a midline position (either in the cul-de-sac or superior to the uterus) associated with a normal ipsilateral ovary. (orig.)

  16. Uterine torsion in a full-term pregnant cat.

    Science.gov (United States)

    Kuroda, Kohei; Osaki, Tomohiro; Harada, Kazuki; Yamashita, Masamichi; Murahata, Yusuke; Azuma, Kazuo; Tsuka, Takeshi; Ito, Norihiko; Imagawa, Tomohiro; Okamoto, Yoshiharu

    2017-01-01

    A 5-year-old intact female Maine Coon cat presented with a 2 day history of lethargy, anorexia and anaemia. The cat had bred 60 days previously and jumped from a height 3 days earlier, which was followed by a worsening of its condition. Ultrasonography revealed that two fetuses had died and one remained alive. Urgent surgical intervention was deemed necessary, and the cat underwent a blood transfusion and laparotomy. The right uterine horn was dark red in appearance and had rotated 360° in the clockwise direction at its base. Subsequently, an ovariohysterectomy and caesarean section were performed, and the fetus in the left uterine horn initially survived. Although the cat appeared to recover from anaemia and physical injury, the kitten died on postoperative day 1. In cases involving only one twisted uterine horn, the fetuses located in the contralateral horn could potentially survive; however, many such fetuses do not survive, and only a few reports have described fetal survival in a pregnant cat with uterine torsion. In the present case, early surgical intervention and blood transfusion allowed us to save the cat. Our findings demonstrate the life-saving abilities of initial support treatment and early surgical intervention for both the pregnant cat and fetuses in cases of acute abdomen caused by uterine torsion.

  17. A new torsion pendulum for gravitational reference sensor technology development

    Science.gov (United States)

    Ciani, Giacomo; Chilton, Andrew; Apple, Stephen; Olatunde, Taiwo; Aitken, Michael; Mueller, Guido; Conklin, John W.

    2017-06-01

    We report on the design and sensitivity of a new torsion pendulum for measuring the performance of ultra-precise inertial sensors and for the development of associated technologies for space-based gravitational wave observatories and geodesy missions. The apparatus comprises a 1 m-long, 50 μm-diameter tungsten fiber that supports an inertial member inside a vacuum system. The inertial member is an aluminum crossbar with four hollow cubic test masses at each end. This structure converts the rotation of the torsion pendulum into translation of the test masses. Two test masses are enclosed in capacitive sensors which provide readout and actuation. These test masses are electrically insulated from the rest of the crossbar and their electrical charge is controlled by photoemission using fiber-coupled ultraviolet light emitting diodes. The capacitive readout measures the test mass displacement with a broadband sensitivity of 30 nm/√{Hz} and is complemented by a laser interferometer with a sensitivity of about 0.5 nm/√{Hz}. The performance of the pendulum, as determined by the measured residual torque noise and expressed in terms of equivalent force acting on a single test mass, is roughly 200 fN/√{Hz} around 2 mHz, which is about a factor of 20 above the thermal noise limit of the fiber.

  18. Giant Meckel’s diverticulum torsion that mimics adnexal pathology

    Directory of Open Access Journals (Sweden)

    Serdar Kirmizi

    2016-01-01

    Full Text Available Meckel’s diverticulum is a real diverticulum located at the antimesenteric portion of intestinal loops and including all layers of the intestinal wall. It is the most common congenital anomaly of the gastrointestinal tract, and its incidence is 1–3%. Many asymptomatic cases are diagnosed when complications occur. A 23-year-old female patient applied to gynaecology emergency clinic with pelvic pain complaint. Laparotomy was performed with the diagnosis of acute abdomen because the physical examination and imaging studies did not exclude tuboovary pathology. Giant Meckel’s diverticulitis and ischemic bowel loops that had been torsion were observed. Obstruction is the most common complication and generally originates from inflammation, adhesions, intussusception and omphalo-mesenteric band. In this case, it was seen that mobilized diverticulitis can be complicated without any fibrous band or adhesion to adjacent organs. This case supports that there can be torsion of bowel in free Meckel’s diverticulum. Meckel’s diverticulum settled in the pelvic region can make a clinical manifestation that is difficult to distinguish from adnexal diseases. It should be kept in mind for cases that start with pelvic pain, form adnexal pathology suspicion and cause an acute abdomen.

  19. Acute gallbladder torsion - a continued pre-operative diagnostic dilemma

    Directory of Open Access Journals (Sweden)

    Desrochers Randal

    2011-04-01

    Full Text Available Abstract Acute gallbladder volvulus continues to remain a relatively uncommon process, manifesting itself usually during exploration for an acute surgical abdomen with a presumptive diagnosis of acute cholecystitis. The pathophysiology is that of mechanical organo-axial torsion along the gallbladder's longitudinal axis involving the cystic duct and cystic artery, and with a pre-requisite of local mesenteric redundancy. The demographic tendency is septua- and octo-genarians of the female sex, and its overall incidence is increasing, this being attributed to increasing life expectancy. We discuss two cases of elderly, fragile women presenting to the emergency department complaining of sudden onset right upper quadrant abdominal pain. Their subsequent evaluation suggested acute cholecystitis. Ultimately both were taken to the operating room where the correct diagnosis of gallbladder torsion was made. Pre-operative diagnosis continues to be a major challenge with only 4 cases reported in the literature diagnosed with pre-operative imaging; the remainder were found intra-operatively. Consequently, a delay in diagnosis can have devastating patient outcomes. Herein we propose a necessary high index of suspicion for gallbladder volvulus in the outlined patient demographic with symptoms and signs mimicking acute cholecystitis.

  20. A strain gradient plasticity theory with application to wire torsion

    KAUST Repository

    Liu, J. X.

    2014-06-05

    Based on the framework of the existing strain gradient plasticity theories, we have examined three kinds of relations for the plastic strain dependence of the material intrinsic length scale, and thus developed updated strain gradient plasticity versions with deformation-dependent characteristic length scales. Wire torsion test is taken as an example to assess existing and newly built constitutive equations. For torsion tests, with increasing plastic strain, a constant intrinsic length predicts too high a torque, while a decreasing intrinsic length scale can produce better predictions instead of the increasing one, different from some published observations. If the Taylor dislocation rule is written in the Nix-Gao form, the derived constitutive equations become singular when the hardening exponent gets close to zero, which seems questionable and calls for further experimental clarifications on the exact coupling of hardening due to statistically stored dislocations and geometrically necessary dislocations. Particularly, when comparing the present model with the mechanism-based strain gradient plasticity, the present model satisfies the reciprocity relation naturally and gives different predictions even under the same parameter setting. © The Author(s) 2014 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

  1. Torsional Ultrasound Sensor Optimization for Soft Tissue Characterization

    Directory of Open Access Journals (Sweden)

    Juan Melchor

    2017-06-01

    Full Text Available Torsion mechanical waves have the capability to characterize shear stiffness moduli of soft tissue. Under this hypothesis, a computational methodology is proposed to design and optimize a piezoelectrics-based transmitter and receiver to generate and measure the response of torsional ultrasonic waves. The procedure employed is divided into two steps: (i a finite element method (FEM is developed to obtain a transmitted and received waveform as well as a resonance frequency of a previous geometry validated with a semi-analytical simplified model and (ii a probabilistic optimality criteria of the design based on inverse problem from the estimation of robust probability of detection (RPOD to maximize the detection of the pathology defined in terms of changes of shear stiffness. This study collects different options of design in two separated models, in transmission and contact, respectively. The main contribution of this work describes a framework to establish such as forward, inverse and optimization procedures to choose a set of appropriate parameters of a transducer. This methodological framework may be generalizable for other different applications.

  2. Prevention of torsion-induced testicular injury by Rhodiola rosea.

    Science.gov (United States)

    Uyeturk, Ugur; Terzi, E Hakan; Gucuk, Adnan; Kemahli, Eray; Ozturk, Hayrettin; Tosun, Mehmet

    2013-07-01

    To evaluate the efficacy of Rhodiola rosea (R. rose) extract in terms of preventing tissue injury induced by testicular torsion and subsequent ischemia/reperfusion (I/R). Twenty-one Wistar albino male rats were divided into 3 groups: group 1 = control group, group 2 = I/R group, and group 3 = I/R + extract group. After 2 hours of ischemia and 4 hours of reperfusion, testes were removed and evaluated histologically by hematoxylin and eosin staining. Apoptosis in spermatogonial cells of seminiferous tubules was determined by transferase biotin-2'-deoxyuridine, 5'-triphosphate nick end labeling (TUNEL). To assess oxidative damage, serum malondialdehyde (MDA) and glutathione (GSH) levels were measured. Median MDA and GSH levels were, respectively, 12 ± 3 pmol/mL and 24.8 ± 3.8 μM in group 1, 38 ± 11 pmol/mL and 10.3 ± 1.7 μM in group 2, and 19 ± 5 pmol/mL and 17.6 ± 1.3 μM in group 3 (P rosea extract was shown to have partially preventive effects on testicular injury induced by torsion in this rat model. The mechanism by which R. rosea extract cause these effects merits further investigation. Copyright © 2013 Elsevier Inc. All rights reserved.

  3. Extravaginal testicular torsion: a clinical entity with unspecified surgical anatomy

    Directory of Open Access Journals (Sweden)

    Iason D. Kyriazis

    2008-10-01

    Full Text Available PURPOSE: To review and evaluate the anatomical definitions of perinatal extravaginal torsion (EVT of the testis. MATERIALS AND METHODS: An extensive review of the literature was made to reveal the prevalent anatomical background predisposing to EVT. Gross appearance of twisted testes obtained during surgery for 14 cases of EVT was used to test the validity of the above theories. RESULTS: The most commonly accepted suggestions describe an EVT within dartos muscle that includes all layers of spermatic cord or an EVT outside parietal layer of tunica vaginalis within internal spermatic fascia. However, both of them were found inadequately documented, while a large volume of controversial data has been accumulated, that raises doubts regarding the validity of such definitions. The gross appearance of twisted testes failed to confirm both an EVT including all layers of the spermatic cord and also an EVT outside tunica vaginalis as possible mechanisms of torsion. CONCLUSION: The anatomical basis of EVT remains unclear and further investigation is required.

  4. Spinning optical resonator sensor for torsional vibrational applications measurements

    Science.gov (United States)

    Ali, Amir R.; Gatherer, Andrew; Ibrahim, Mariam S.

    2016-03-01

    Spinning spherical resonators in the torsional vibrational applications could cause a shift in its whispering gallery mode (WGM). The centripetal force acting on the spinning micro sphere resonator will leads to these WGM shifts. An analysis and experiment were carried out in this paper to investigate and demonstrate this effect using different polymeric resonators. In this experiment, centripetal force exerted by the DC-Motor on the sphere induces an elastic deformation of the resonator. This in turn induces a shift in the whispering gallery modes of the sphere resonator. Materials used for the sphere are polydimethylsiloxane (PDMS 60:1 where 60 parts base silicon elastomer to 1 part polymer curing agent by volume) with shear modulus (G≍1kPa), (PDMS 10:1) with shear modulus (G≍300kPa), polymethylmethacrylate (PMMA, G≍2.6×109GPa) and silica (G≍3×1010 GPa). The sphere size was kept constant with 1mm in diameter for all above materials. The optical modes of the sphere exit using a tapered single mode optical fiber that is coupled to a distributed feedback laser. The transmission spectrum through the fiber is monitored to detect WGM shifts. The results showed the resonators with smaller shear modulus G experience larger WGM shift due to the larger mechanical deformation induced by the applied external centripetal force. Also, the results show that angular velocity sensors used in the torsional vibrational applications could be designed using this principle.

  5. Axial and torsional stiffness of pediatric prosthetic feet.

    Science.gov (United States)

    Taboga, Paolo; Grabowski, Alena M

    2017-02-01

    Prosthetic stiffness likely affects the walking biomechanics of toddlers and children with leg amputations, but the actual stiffness values for prostheses are not reported by manufacturers or in standardized testing procedures. We measured axial (k A ) and torsional (k T ) stiffness from four brands of pediatric prosthetic feet (Trulife, Kingsley Mfg. Co., TRS Incorporated, and College Park Industries) over a range of foot sizes. We applied forces and torques onto prostheses with a materials testing machine that replicated those exhibited in vivo by using the kinetics measured from four non-amputee toddlers (2-3years) during walking. Across brands, k A averaged 35.2kN/m during heel loading, was more stiff during midfoot loading (121.8kN/m, Pfeet. Plantarflexion torsional stiffness (k T1 ), was not statistically different across brands. For every 1cm increase in foot size, k T1 increased 0.16kN·m/rad (Pfeet should be publically reported to health practitioners to ensure evidence-based decisions and meet the specific needs of each patient with a leg amputation. Copyright © 2017 Elsevier Ltd. All rights reserved.

  6. Rheology of deformed Carrara marble: Insights from torsion experiments

    Science.gov (United States)

    Bruijn, R. H. C.; Delle Piane, C.; de Raadt, W. S.

    2012-04-01

    Rock deformation experiments are essential for understanding lithosphere dynamics, strain localization processes and deformation mechanisms in polymineral aggregates, as they provide rheological parameters and record fabric development of rock-forming minerals, aiding the geological interpretation of naturally deformed rocks. Carrara marble received significant attention in the rock deformation community due to its homogeneous fabric and low impurities content, making it a laboratory standard. When the torsion actuator was developed for the Paterson-type gas-medium apparatus, it became possible to perform high strain experiments and reach true steady state flow conditions in Carrara marble. At the center of these ground breakings developments stood Luigi Burlini and his students. Their work showed for the first time, the importance of fabric development on steady state flow stress in response to high strain deformation and recrystallization. In the last years of Luigi's life, he and his students took rock deformation studies to a different direction by investigating the effect of initial strain and quantifying the coupling between fabric and flow stress. We present here an overview of the four types of torsion experiment that were performed on Carrara marble with varied pre-existing strain. Earlier torsion experiments on homogeneous Carrara marble provided the framework in which these newer experiments were evaluated. In type I experiments samples were subjected to a torsion deformation leading to a maximum shear strain of 1 to 5, immediately followed by a reversed straining of equal magnitude. In type II and III experiments, a composite sample consisting of a segment of undeformed and one (type II) or two (type III) segment(s) of previously twisted Carrara marble, were deformed. In type IV experiments, a cylindrical segment of dynamically recrystallized Carrara marble was annealed 727 °C for up to five hours at to recover the original grain size without removing

  7. Pictorial review: Foot axes and angles

    OpenAIRE

    Gentili, A; Masih, S; Yao, L; Seeger, LL

    1996-01-01

    Using radiographs and diagrams, this article reviews the most commonly used axes and angles of the foot, including: longitudinal axis of the rearfoot, collum tall axis, talocalcaneal angle, cuboid abduction angle, longitudinal axis of the lesser tarsus, lesser tarsus angle, talonavicular angle, longitudinal axis of the metatarsus, forefoot adductus angle, metatarsus adductus angle, first intermetatarsal angle, hallux valgus angle, proximal and distal articular set angles, and hallux interphal...

  8. Improving prediction of secondary structure, local backbone angles, and solvent accessible surface area of proteins by iterative deep learning.

    Science.gov (United States)

    Heffernan, Rhys; Paliwal, Kuldip; Lyons, James; Dehzangi, Abdollah; Sharma, Alok; Wang, Jihua; Sattar, Abdul; Yang, Yuedong; Zhou, Yaoqi

    2015-06-22

    Direct prediction of protein structure from sequence is a challenging problem. An effective approach is to break it up into independent sub-problems. These sub-problems such as prediction of protein secondary structure can then be solved independently. In a previous study, we found that an iterative use of predicted secondary structure and backbone torsion angles can further improve secondary structure and torsion angle prediction. In this study, we expand the iterative features to include solvent accessible surface area and backbone angles and dihedrals based on Cα atoms. By using a deep learning neural network in three iterations, we achieved 82% accuracy for secondary structure prediction, 0.76 for the correlation coefficient between predicted and actual solvent accessible surface area, 19° and 30° for mean absolute errors of backbone φ and ψ angles, respectively, and 8° and 32° for mean absolute errors of Cα-based θ and τ angles, respectively, for an independent test dataset of 1199 proteins. The accuracy of the method is slightly lower for 72 CASP 11 targets but much higher than those of model structures from current state-of-the-art techniques. This suggests the potentially beneficial use of these predicted properties for model assessment and ranking.

  9. Ocular torsion as a test of the asymmetry hypothesis of space motion sickness

    Science.gov (United States)

    Diamond, Shirley G.; Markham, Charles H.

    linear and angular acceleration to the head and by visual stimuli. Between one-half and two-thirds of astronauts and cosmonauts have SMS 3 — and the remainder do not. The most likely explanation is the hypothesis advanced by von Baumgarten and Thümler, 1 i.e. in certain individuals there is an asymmetry in the otolith apparatus on the two sides of the head which becomes compensated in a lifetime in a 1 G environment, but this compensation is lost when exposed to the hypogravity of space flight. One thing that makes SMS unique is that there is no correlation with motion sickness in a earth-based environment, whether it be on land, sea or in the air. This is perhaps the main reason it has not been possible, until the present investigations, to predict who would get SMS. We shall review here work relating alterations in ocular torsional movements induced by repeated exposure to transient episodes of O G and 1.8 G during parabolic airplane flight to SMS. Several questions were asked: Could we predict in a blinded analysis which astronaut-subjects had had prior SMS (and which had not)? Based on what appears to be a positive answer, 4 we then asked whether the observed ocular torsional disconjugacy could be modified by an increasing number of parabolas; and whether observed disconjugacy seen in the subject in the upright position could be reduced or "nulled" by parabolic stimuli with the subjects tipped at different angles in the right ear down and left ear down directions.

  10. Lorentz violation bounds from torsion trace fermion sector and galaxy M 51 data and chiral dynamos

    Science.gov (United States)

    Garcia de Andrade, L. C.

    2017-06-01

    Earlier we have computed a Lorentz violation (LV) bound for torsion terms via galactic dynamos and found bounds similar to the one obtained by Kostelecky et al. (Phys Rev Lett 100:111102, 2008) which is of the order of 10^{-31} GeV. Their result was found making use of the axial torsion vector in terms of Dirac spinors and minimal torsion coupling in flat space-time of fermions. In this paper, a torsion dynamo equation obtained using the variation of the torsion trace and galaxy M51 data of 500 pc are used to place an upper bound of 10^{-26} GeV in LV, which agrees with the one by Kostelecky and his group using an astrophysical framework background. Their lowest bound was obtained in earth laboratory using dual masers. One of the purposes of this paper is to apply the Faraday self-induction magnetic equation, recently extended to torsioned space-time, by the author to show that it lends support to physics in Riemann-Cartan space-time, in several distinct physical backgrounds. Backreaction magnetic effects are used to obtain the LV bounds. Previously Bamba et al. (JCAP 10:058, 2012) have used the torsion trace in their teleparallel investigation of the IGMF, with the argument that the torsion trace leads to less weaker effects than the other irreducible components of the torsion tensor. LV is computed in terms of a chiral-torsion-like current in the new dynamo equation analogous to the Dvornikov and Semikoz dynamo equation with chiral magnetic currents. Making use of the chiral-torsion dynamo equation we estimate the LV bounds in the early universe to be of the order of 10^{-24} GeV, which was the order of the charged-lepton sector. Our main result is that it is possible to obtain more stringent bounds than the ones found in the fermion sector of astrophysics in the new revised 2017 data table for CPT and Lorentz violation by Kostelecky and Mewes. They found in several astrophysical backgrounds, orders of magnitude such as 10^{-24} and 10^{-23} GeV which are not so

  11. Lorentz violation bounds from torsion trace fermion sector and galaxy M51 data and chiral dynamos

    Energy Technology Data Exchange (ETDEWEB)

    Garcia de Andrade, L.C. [IF-UERJ, Departamento de Fisica Teorica, Rio de Janeiro, RJ (Brazil)

    2017-06-15

    Earlier we have computed a Lorentz violation (LV) bound for torsion terms via galactic dynamos and found bounds similar to the one obtained by Kostelecky et al. (Phys Rev Lett 100:111102, 2008) which is of the order of 10{sup -31} GeV. Their result was found making use of the axial torsion vector in terms of Dirac spinors and minimal torsion coupling in flat space-time of fermions. In this paper, a torsion dynamo equation obtained using the variation of the torsion trace and galaxy M51 data of 500 pc are used to place an upper bound of 10{sup -26} GeV in LV, which agrees with the one by Kostelecky and his group using an astrophysical framework background. Their lowest bound was obtained in earth laboratory using dual masers. One of the purposes of this paper is to apply the Faraday self-induction magnetic equation, recently extended to torsioned space-time, by the author to show that it lends support to physics in Riemann-Cartan space-time, in several distinct physical backgrounds. Backreaction magnetic effects are used to obtain the LV bounds. Previously Bamba et al. (JCAP 10:058, 2012) have used the torsion trace in their teleparallel investigation of the IGMF, with the argument that the torsion trace leads to less weaker effects than the other irreducible components of the torsion tensor. LV is computed in terms of a chiral-torsion-like current in the new dynamo equation analogous to the Dvornikov and Semikoz dynamo equation with chiral magnetic currents. Making use of the chiral-torsion dynamo equation we estimate the LV bounds in the early universe to be of the order of 10{sup -24} GeV, which was the order of the charged-lepton sector. Our main result is that it is possible to obtain more stringent bounds than the ones found in the fermion sector of astrophysics in the new revised 2017 data table for CPT and Lorentz violation by Kostelecky and Mewes. They found in several astrophysical backgrounds, orders of magnitude such as 10{sup -24} and 10{sup -23} Ge

  12. Heterodyne Interferometer Angle Metrology

    Science.gov (United States)

    Hahn, Inseob; Weilert, Mark A.; Wang, Xu; Goullioud, Renaud

    2010-01-01

    A compact, high-resolution angle measurement instrument has been developed that is based on a heterodyne interferometer. The common-path heterodyne interferometer metrology is used to measure displacements of a reflective target surface. In the interferometer setup, an optical mask is used to sample the measurement laser beam reflecting back from a target surface. Angular rotations, around two orthogonal axes in a plane perpendicular to the measurement- beam propagation direction, are determined simultaneously from the relative displacement measurement of the target surface. The device is used in a tracking telescope system where pitch and yaw measurements of a flat mirror were simultaneously performed with a sensitivity of 0.1 nrad, per second, and a measuring range of 0.15 mrad at a working distance of an order of a meter. The nonlinearity of the device is also measured less than one percent over the measurement range.

  13. different outer cone angle

    Directory of Open Access Journals (Sweden)

    Smyk Emil

    2017-01-01

    Full Text Available One of the method of flow separation control is application of axisymmetric valve. It is composed of nozzle with core. Normally the main flow is attached to inner cone and flow by preferential collector to primary flow pipe. If through control nozzle starts flow jet (control jet the main flow is switched to annular secondary collector. In both situation the main flow is deflected to inner or outer cone (placed at the outlet of the valve’s nozzle by Coanda effect. The paper deals with the numerical simulation of this axisymetric annular nozzle with integrated synthetic jet actuator. The aim of the work is influence examination of outer cone angle on deflection on main stream.

  14. The role of nonlinear torsional contributions on the stability of flexural-torsional oscillations of open-cross section beams

    Science.gov (United States)

    Di Egidio, Angelo; Contento, Alessandro; Vestroni, Fabrizio

    2015-12-01

    An open-cross section thin-walled beam model, already developed by the authors, has been conveniently simplified while maintaining the capacity of accounting for the significant nonlinear warping effects. For a technical range of geometrical and mechanical characteristics of the beam, the response is characterized by the torsional curvature prevailing over the flexural ones. A Galerkin discretization is performed by using a suitable expansion of displacements based on shape functions. The attention is focused on the dynamic response of the beam to a harmonic force, applied at the free end of the cantilever beam. The excitation is directed along the symmetry axis of the beam section. The stability of the one-component oscillations has been investigated using the analytical model, showing the importance of the internal resonances due to the nonlinear warping coupling terms. Comparison with the results provided by a computational finite element model has been performed. The good agreement among the results of the analytical and the computational models confirms the effectiveness of the simplified model of a nonlinear open-cross section thin-walled beam and overall the important role of the warping and of the torsional elongation in the study of the one-component dynamic oscillations and their stability.

  15. Tilt boundary formation in GeSi/Si (001 vicinal heterosystem

    Directory of Open Access Journals (Sweden)

    Aleksei V. Kolesnikov

    2015-03-01

    Full Text Available The structural state of GexSi1-x films grown on Si substrates with the vicinal orientation (1 1 13 has been studied. The (1 1 13 orientation has been obtained by rotating the singular plane (001 around the [1 1 ¯0] axis. The x parameter of GexSi1-x films in different samples ranged from 0.083 to 0.268. Triclinic distortions arising in film crystal lattice have been analyzed using our technique developed for the determination of epitaxial layer structural parameters based on the X-ray diffractometry data. It has been established that during the epitaxial process the film lattice turns around the direction of surface steps due to the introduction of misfit dislocations into the interface. Dislocations with Burgers vector a/2〈110〉 which is not parallel to the interface create an analog of a tilt boundary. The turning angle value ψ is proportional to the misfit dislocation density. This phenomenon is associated with a decrease of the interface symmetry that leads to a change in the efficiency of stress relieving by dislocations belonging to different families. The influence of these families on the low-angle boundary formation is considered. Experimental values of the ψ angle and shear strain for the [13 13 2¯] and [1¯ 1 0] directions lying in the interface (1 1 13 have been defined. A comparison of the experimental and calculated values of ψ for the [13 13 2¯] direction is provided.

  16. Omental torsion in acute abdomen: a case report

    Directory of Open Access Journals (Sweden)

    Alibakhshi A

    2010-01-01

    Full Text Available "n Normal 0 false false false EN-US X-NONE AR-SA MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:Arial; mso-bidi-theme-font:minor-bidi;} Background: Management of acute abdomen usually does not necessitate accurate pre-operative diagnosis but the surgeon should make a decision about the need for emergent laparotomy. This fact is somehow different for localized peritonitis (e.g. acute appendicitis in which the clinical presentation directs straightly to the diagnosis. However, acute appendicitis has lots of differential diagnoses, finding the normal appendix during laparotomy is just a start point to look for other diagnoses. Omental torsion is a rare cause for acute abdomen that is usually missed. Knowing about this rare condition and its frequently encountered presentation at the operating room (sero-sanguinous fluid coming out of peritoneal cavity may prevent missing the diagnosis and doing a malpractice."n"nCase report: Report a 9 year- old boy presented with acute abdomen which turned out to be an omental torsion after the operation."n"nConclusion: Knowledge about this rare condition "omental torsion" and its clinical and intra operative presentations may prevent missing the diagnosis and a malpractice.

  17. Dose-dependent protective effect of baicalin against testicular torsion-detorsion in rats.

    Science.gov (United States)

    Fouad, A A; Qutub, H O; Jresat, I

    2017-02-01

    Testicular torsion/detorsion induces oxidative/nitrosative stress, inflammation and apoptosis of testicular tissues. Baicalin exerts antioxidant and anti-inflammatory properties. This study investigated the possible protective effect of baicalin against testicular torsion-detorsion injury in rats. Surgical testicular torsion was induced for 2 h, followed by detorsion which was continued for 24 h. Baicalin was administered in three different doses (25, 50 and 100 mg kg-1 , by intraperitoneal injection). Each dose was given twice, the first 30 min before and the second 12 h after testicular detorsion. Baicalin, in a dose-dependent manner, decreased the torsion/detorsion-induced elevations of testicular malondialdehyde, nitric oxide, tumour necrosis factor-α, BCL2-associated X protein (Bax), cytosolic cytochrome c and caspase-3 and caspase-9 activities. Baicalin, dose dependently, attenuated the reductions of B-cell leucemia/lymphoma 2 (Bcl-2), and glutathione peroxidase and superoxide dismutase activities in testicular tissues resulted from torsion/detorsion. In addition, baicalin ameliorated the histopathological testicular tissue damage and reduced the expression of Fas ligand in rat testes exposed to torsion/detorsion in a dose-dependent manner. It was concluded that baicalin, dose dependently, ameliorated testicular injury induced by torsion/detorsion via its antioxidant, antinitrosative, anti-inflammatory and anti-apoptotic effects. © 2016 Blackwell Verlag GmbH.

  18. Study on Forced Torsional Vibration of CFRP Drive-Line System with Internal Damping

    Science.gov (United States)

    Yang, Mo; Hu, Yefa; Zhang, Jinguang; Ding, Guoping; Song, Chunsheng

    2017-12-01

    The use of CFRP transmission shaft has positive effect on the weight and flexural vibration reduction of drive-line system. However, the application of CFRP transmission shaft will greatly reduce the torsional stiffness of the drive-line, and may cause strong transient torsional vibration. Which will seriously affect the performance of CFRP drive-line. In this study, the forced torsional vibration of the CFRP drive-line system is carried out using the lumped parameter model. In addition, the effect of rotary inertia, internal damping, coupling due to the composite laminate, and excitation torque are incorporated in the modified transfer matrix model (TMM). Then, the modified TMM is used to predict the torsional frequency and forced torsional vibration of a CFRP drive-line with three-segment drive shafts. The results of modified TMM shown that the rotational speed difference of the CFRP transmission shaft segment is much larger than metal transmission shaft segment under excitation torque. And compared the results from finite element simulation, modified TMM and torsional vibration experiment respectively, and it has shown that the modified TMM can accurately predict forced torsional vibration behaviors of the CFRP drive-line system.

  19. Transabdominal color doppler ultrasonography: A relevant approach for assessment of effects of uterine torsion in buffaloes

    Directory of Open Access Journals (Sweden)

    Devender

    2016-08-01

    Full Text Available Aim: The present study was conducted on advanced pregnant buffaloes suffering from uterine torsion to assess the status of fetus and uterus by transabdominal ultrasonography, and the findings were compared with normal advanced pregnant buffaloes. Materials and Methods: The study was conducted on 20 clinical cases of uterine torsion and 20 normal advanced pregnant buffaloes (control group. The lower ventral area just lateral to linea alba (on both sides of the udder in standing animals was scanned transabdominally by the two-dimensional convex transducer for various ultrasonographic findings. The data collected were statistically analyzed by “one-way ANOVA” and “independent sample t-test” using computerized SPSS 16.0 software program. Results: Transabdominal ultrasonography revealed dead fetus in 95% uterine torsion cases and proved useful in imaging internal structures of fetuses while no dead fetus was reported in the control group. Size of umbilicus was found significantly decreased (p0.05 in uterine torsion group. Average thickness of the uterine wall and mean pixel values of fetal fluids (echogenicity were found significantly increased (p<0.05 in uterine torsion affected buffaloes in comparison to control group. Conclusion: Status of fetus (whether live or dead, internal status of uterus, and its contents could be determined by transabdominal ultrasonography in uterine torsion cases and thus determining the prognosis of the uterine torsion cases before going for further manipulations. This will also help in taking all the precautions to avoid death of the fetus.

  20. Experimental investigation on rectangular reinforced concrete beam subjected to bi-axial shear and torsion

    Directory of Open Access Journals (Sweden)

    Chayanon Hansapinyo

    2003-01-01

    Full Text Available This paper presents the experimental investigation on the failure mechanism and ultimate capacity of rectangular reinforced concrete beam under combined action of bi-axial shear accompanied with torsion through the test of four reinforced concrete members. The simple experimental set-up for a simply-supported beam under one point loading is introduced in this study by applying eccentric load to the tilted beam. This requires only one hydraulic jack to produce the complicated bi-axial shear and torsional loading. The main parameter is the magnitude of torsion induced to specimens which is relatively represented by the torsion-to-shear ratio. In addition, the influence of torsion on ultimate capacity of reinforced concrete with different ratio of two shears is investigated. From the experimental results, it is found that the increase in the magnitude of torsion about 69 percent drastically decreases bi-axial shear capacity as much as 12 to 39 percent according to the ratio of bi-axial shears. The experimental results are compared with the capacities calculated by the available interaction formula between uni-axial shear and torsion in the current design codes. The comparison indicates that the current design codes give quite conservative values of ultimate capacity.

  1. Transabdominal color doppler ultrasonography: A relevant approach for assessment of effects of uterine torsion in buffaloes.

    Science.gov (United States)

    Devender; Chandolia, Ramesh Kumar; Pandey, Anand Kumar; Yadav, Vishal; Kumar, Parveen; Dalal, Jasmer

    2016-08-01

    The present study was conducted on advanced pregnant buffaloes suffering from uterine torsion to assess the status of fetus and uterus by transabdominal ultrasonography, and the findings were compared with normal advanced pregnant buffaloes. The study was conducted on 20 clinical cases of uterine torsion and 20 normal advanced pregnant buffaloes (control group). The lower ventral area just lateral to linea alba (on both sides of the udder) in standing animals was scanned transabdominally by the two-dimensional convex transducer for various ultrasonographic findings. The data collected were statistically analyzed by "one-way ANOVA" and "independent sample t-test" using computerized SPSS 16.0 software program. Transabdominal ultrasonography revealed dead fetus in 95% uterine torsion cases and proved useful in imaging internal structures of fetuses while no dead fetus was reported in the control group. Size of umbilicus was found significantly decreased (p0.05) in uterine torsion group. Average thickness of the uterine wall and mean pixel values of fetal fluids (echogenicity) were found significantly increased (p<0.05) in uterine torsion affected buffaloes in comparison to control group. Status of fetus (whether live or dead), internal status of uterus, and its contents could be determined by transabdominal ultrasonography in uterine torsion cases and thus determining the prognosis of the uterine torsion cases before going for further manipulations. This will also help in taking all the precautions to avoid death of the fetus.

  2. Radiation Field in the Vicinity of the Collider Center

    Energy Technology Data Exchange (ETDEWEB)

    Stevens, A. J. [Brookhaven National Lab. (BNL), Upton, NY (United States)

    1994-10-26

    The Collider Center and the adjoining cryogenic support building are unique among the buildings close to the collider tunnel because these are locations where the occupancy by non-radiation workers is high. This note describes calculations of the dose equivalent from local beam loss at both the nearest point of these buildings to the collider ring and on the berm in the vicinity of these buildings.

  3. Environmental surveillance in the vicinity of Hanford for January 1968

    Energy Technology Data Exchange (ETDEWEB)

    Wooldridge, C.B. (ed.)

    1968-04-15

    The concentrations of most radionuclides in the vicinity of Hanford during January 1968 were below comparable measurements for a year ago. Slightly increased concentrations of I-131 in Richland drinking water were observed during the last two weeks of the month. Radioiodine detected in several milk samples (maximum 25 pCi/l) was attributed to fallout from an announced nuclear weapons test of December 24, 1967. Increased beta activities on air filters were also attributed to fallout.

  4. Determining the shear fracture properties of HIP joints of reduced-activation ferritic/martensitic steel by a torsion test

    Science.gov (United States)

    Nozawa, Takashi; Noh, Sanghoon; Tanigawa, Hiroyasu

    2012-08-01

    Hot isostatic pressing (HIP) is a key technology used to fabricate a first wall with cooling channels for the fusion blanket system utilizing a reduced-activation ferritic/martensitic steel. To qualify the HIPped components, small specimen test techniques are beneficial not only to evaluate the thin-wall cooling channels containing the HIP joint but also to use in neutron irradiation studies. This study aims to develop the torsion test method with special emphasis on providing a reasonable and comprehensive method to determine interfacial shear properties of HIP joints during the torsional fracture process. Torsion test results identified that the torsion process shows yield of the base metal followed by non-elastic deformation due to work hardening of the base metal. By considering this work hardening issue, we propose a reasonable and realistic solution to determine the torsional yield shear stress and the ultimate torsional shear strength of the HIPped interface. Finally, a representative torsion fracture process was identified.

  5. Optical monitoring of testicular torsion using a miniaturized near infrared spectroscopy sensor

    Science.gov (United States)

    Shadgan, Babak; Kajbafzadeh, Majid; Nigro, Mark; Kajbafzadeh, A. M.; Macnab, Andrew

    2017-02-01

    Background: Testicular torsion is an acute urological emergency occurring in children and adolescents. Accurate and fast diagnosis is important as the resulting ischemia can destroy the testis. Currently, Doppler ultrasound is the preferred diagnostic method. Ultrasound is not readily available in all centers which may delay surgical treatment. In this study, a rat model was used to examine the feasibility and sensitivity of using spatially-resolved near infrared spectroscopy (SR-NIRS) with a custom-made miniaturized optical sensor probe to detect and study changes in testicular hemodynamics and oxygenation during three degrees of induced testicular torsion, and after detorsion. Methods: Eight anesthetized rats (16 testes) were studied using SR-NIRS with the miniaturized optical probe applied directly onto the surface of the surgically exposed testis during 360, 720 and 1080 degrees of torsion followed by detorsion. Oxygenated, deoxygenated and total hemoglobin and TOI% were studied pre-and post-manipulations. Results: NIRS monitoring reflected acute testicular ischemia and hypoxia on induction of torsion, and tissue reperfusionreoxygenation after detorsion. Testicular torsion at 720 degrees induced the maximum observed degree of hypoxic changes. In all cases, rhythmic changes were observed in the NIRS signals before inducing torsion; these disappeared after applying 360 degrees of torsion and did not reappear after detorsion. Conclusion: This animal study indicates that SR-NIRS monitoring of the testes using a directly applied miniature sensor is a feasible and sensitive method to detect testicular ischemia and hypoxia immediately after torsion occurs, and testicular reperfusion upon detorsion. This study offers the potential for a SR-NIRS system with a miniaturized sensor to be explored further as a rapid, noninvasive, optical method for detecting testicular torsion in children.

  6. MERA: a webserver for evaluating backbone torsion angle distributions in dynamic and disordered proteins from NMR data

    Energy Technology Data Exchange (ETDEWEB)

    Mantsyzov, Alexey B. [M.V. Lomonosov Moscow State University, Faculty of Fundamental Medicine (Russian Federation); Shen, Yang; Lee, Jung Ho [National Institutes of Health, Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases (United States); Hummer, Gerhard [Max Planck Institute of Biophysics (Germany); Bax, Ad, E-mail: bax@nih.gov [National Institutes of Health, Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases (United States)

    2015-09-15

    MERA (Maximum Entropy Ramachandran map Analysis from NMR data) is a new webserver that generates residue-by-residue Ramachandran map distributions for disordered proteins or disordered regions in proteins on the basis of experimental NMR parameters. As input data, the program currently utilizes up to 12 different parameters. These include three different types of short-range NOEs, three types of backbone chemical shifts ({sup 15}N, {sup 13}C{sup α}, and {sup 13}C′), six types of J couplings ({sup 3}J{sub HNHα}, {sup 3}J{sub C′C′}, {sup 3}J{sub C′Hα}, {sup 1}J{sub HαCα}, {sup 2}J{sub CαN} and {sup 1}J{sub CαN}), as well as the {sup 15}N-relaxation derived J(0) spectral density. The Ramachandran map distributions are reported in terms of populations of their 15° × 15° voxels, and an adjustable maximum entropy weight factor is available to ensure that the obtained distributions will not deviate more from a newly derived coil library distribution than required to account for the experimental data. MERA output includes the agreement between each input parameter and its distribution-derived value. As an application, we demonstrate performance of the program for several residues in the intrinsically disordered protein α-synuclein, as well as for several static and dynamic residues in the folded protein GB3.

  7. Cofactor-binding sites in proteins of deviating sequence: comparative analysis and clustering in torsion angle, cavity, and fold space.

    Science.gov (United States)

    Stegemann, Björn; Klebe, Gerhard

    2012-02-01

    Small molecules are recognized in protein-binding pockets through surface-exposed physicochemical properties. To optimize binding, they have to adopt a conformation corresponding to a local energy minimum within the formed protein-ligand complex. However, their conformational flexibility makes them competent to bind not only to homologous proteins of the same family but also to proteins of remote similarity with respect to the shape of the binding pockets and folding pattern. Considering drug action, such observations can give rise to unexpected and undesired cross reactivity. In this study, datasets of six different cofactors (ADP, ATP, NAD(P)(H), FAD, and acetyl CoA, sharing an adenosine diphosphate moiety as common substructure), observed in multiple crystal structures of protein-cofactor complexes exhibiting sequence identity below 25%, have been analyzed for the conformational properties of the bound ligands, the distribution of physicochemical properties in the accommodating protein-binding pockets, and the local folding patterns next to the cofactor-binding site. State-of-the-art clustering techniques have been applied to group the different protein-cofactor complexes in the different spaces. Interestingly, clustering in cavity (Cavbase) and fold space (DALI) reveals virtually the same data structuring. Remarkable relationships can be found among the different spaces. They provide information on how conformations are conserved across the host proteins and which distinct local cavity and fold motifs recognize the different portions of the cofactors. In those cases, where different cofactors are found to be accommodated in a similar fashion to the same fold motifs, only a commonly shared substructure of the cofactors is used for the recognition process. Copyright © 2011 Wiley Periodicals, Inc.

  8. Testicular Torsion in Cerebral Palsy - Resident's Grey Area.

    Science.gov (United States)

    Ghalige, Hemanth S; N, Babitha; Maibam, Chetan; Sharma, M Birkumar; Singh, Th Sudhir Chandra

    2014-10-01

    The association of testicular torsion and cerebral palsy is a well-known fact. But the infrequent presentation to emergency room makes the clinician sceptical. Such a presentation often puzzles the residents regarding the diagnosis and the treatment. Here we present a case of an adolescent boy aged with cerebral palsy 13 years with incessant crying and not feeding well for last 3days. Right inguinal region showed a tender globular swelling with absence of testis in scrotum along with signs of septicaemia. The inguinal exploration was performed under general anaesthesia which revealed gangrenous right testis. Right orchidectomy and left orchidopexy was performed and the patient recovered well. This case is reported for its complexity due to lack of reliable history, delayed presentation and associated comorbidities posing challenges to the treating surgeons.

  9. Stick-slip and Torsional Friction Factors in Inclined Wellbores

    Directory of Open Access Journals (Sweden)

    Aarsnes Ulf Jakob F.

    2018-01-01

    The model is shown to have a good match with the surface and downhole behavior of two deviated wellbores for depths ranging from 1500 to 3000 meters. In particular, the model replicates the amplitude and period of the oscillations, in both the topside torque and the downhole RPM, as caused by the along-string stick slip. It is further shown that by using the surface behavior of the drill-string during rotational startup, an estimate of the static and dynamic friction factors along the wellbore can be obtained, even during stick-slip oscillations, if axial tension in the drillstring is considered. This presents a possible method to estimate friction factors in the field when off-bottom stick slip is encountered, and points in the direction of avoiding stick slip through the design of an appropriate torsional start-up procedure without the need of an explicit friction test.

  10. Appearance of singularities of optical fields under torsion of crystals containing threefold symmetry axes.

    Science.gov (United States)

    Skab, Ihor; Vasylkiv, Yurij; Zapeka, Bohdan; Savaryn, Viktoriya; Vlokh, Rostyslav

    2011-07-01

    We present an analysis of the effect of torsion stresses on the spatial distribution of optical birefringence in crystals of different point symmetry groups. The symmetry requirements needed so that the optical beam carries dislocations of the phase front are evaluated for the case when the crystals are twisted and the beam closely corresponds to a plane wave. It is shown that the torsion stresses can produce screw-edge, pure screw, or pure edge dislocations of the phase front in the crystals belonging to cubic and trigonal systems. The conditions for appearance of canonical and noncanonical vortices in the conditions of crystal torsion are analyzed. © 2011 Optical Society of America

  11. Torsion biomechanics of the spine following lumbar laminectomy: a human cadaver study.

    Science.gov (United States)

    Bisschop, Arno; van Dieën, Jaap H; Kingma, Idsart; van der Veen, Albert J; Jiya, Timothy U; Mullender, Margriet G; Paul, Cornelis P L; de Kleuver, Marinus; van Royen, Barend J

    2013-08-01

    Lumbar laminectomy affects spinal stability in shear loading. However, the effects of laminectomy on torsion biomechanics are unknown. The purpose of this study was to investigate the effect of laminectomy on torsion stiffness and torsion strength of lumbar spinal segments following laminectomy and whether these biomechanical parameters are affected by disc degeneration and bone mineral density (BMD). Ten human cadaveric lumbar spines were obtained (age 75.5, range 59-88). Disc degeneration (MRI) and BMD (DXA) were assessed. Disc degeneration was classified according to Pfirrmann and dichotomized in mild or severe. BMD was defined as high BMD (≥median BMD) or low BMD (biomechanical effects of a lumbar laminectomy.

  12. Longitudinal colonic torsion as a cause of tenesmus in an adult Irish Water Spaniel.

    Science.gov (United States)

    Milner, H R; Newington, A N

    2004-02-01

    Torsion of the descending colon was diagnosed by barium enema radiography in an adult Irish Water Spaniel which had presented with tenesmus of 24 h duration. Treatment involved exploratory laparotomy, repositioning of the colon, colopexy and repair of a mesenteric rent. No definitive cause of the torsion could be established. The dog made an uneventful recovery from surgery. Animals presenting with constipation of undetermined cause should have large intestinal obstruction ruled out prior to administering bowel cleansing solutions per os and/or colonic enemas. Colonic obstruction by torsion should be considered as a possible differential diagnosis in all cases of tenesmus.

  13. Fiber-Optic Sensors for Measurements of Torsion, Twist and Rotation: A Review.

    Science.gov (United States)

    Budinski, Vedran; Donlagic, Denis

    2017-02-23

    Optical measurement of mechanical parameters is gaining significant commercial interest in different industry sectors. Torsion, twist and rotation are among the very frequently measured mechanical parameters. Recently, twist/torsion/rotation sensors have become a topic of intense fiber-optic sensor research. Various sensing concepts have been reported. Many of those have different properties and performances, and many of them still need to be proven in out-of-the laboratory use. This paper provides an overview of basic approaches and a review of current state-of-the-art in fiber optic sensors for measurements of torsion, twist and/or rotation.Invited Paper.

  14. Fiber-Optic Sensors for Measurements of Torsion, Twist and Rotation: A Review †

    Science.gov (United States)

    Budinski, Vedran; Donlagic, Denis

    2017-01-01

    Optical measurement of mechanical parameters is gaining significant commercial interest in different industry sectors. Torsion, twist and rotation are among the very frequently measured mechanical parameters. Recently, twist/torsion/rotation sensors have become a topic of intense fiber-optic sensor research. Various sensing concepts have been reported. Many of those have different properties and performances, and many of them still need to be proven in out-of-the laboratory use. This paper provides an overview of basic approaches and a review of current state-of-the-art in fiber optic sensors for measurements of torsion, twist and/or rotation. PMID:28241510

  15. Single umbilical artery and umbilical cord torsion leading to fetal death. A case report.

    Science.gov (United States)

    Hadar, Amnon; Hallak, Mordechai

    2003-09-01

    Intrauterine fetal death is a complication that cannot often be predicted by standard obstetric management. Cord accident may be responsible for about 5% of cases. Umbilical cord torsion is an extremely rare cause of intrauterine fetal death. An 18-year-old, nulliparous woman presented with a complaint of decreased fetal movement at 38 weeks' gestation. Intrauterine fetal death was diagnosed on ultrasound. The pathologic examination revealed umbilical cord torsion and confirmed a single umbilical artery that was diagnosed on ultrasound. Umbilical cord torsion that leads to intrauterine fetal death is extremely rare. A pregnancy with a single umbilical artery may need fetal monitoring during the third trimester.

  16. Numerical Investigation of Damping of Torsional Beam Vibrations by Viscous Bimoments

    DEFF Research Database (Denmark)

    Hoffmeyer, David; Høgsberg, Jan Becker

    2017-01-01

    Damping of torsional beam vibrations of slender beam–structures with thin–walled cross–sections is investigated. Analytical results from solving the differential equation governing torsion with viscous bimoments imposed at the boundary, are compared with a numerical approach with three......–dimensional, is oparametric elements. The viscous bimoments act on the axial warping displacements associated with in homogeneous torsion, and are in a numerical format realized by suitable configurations of concentrated, axial forces describing discrete dampers.It is illustrated by an example that significant damping ratios...

  17. Generators for the l-torsion subgroup of Jacobians of Genus Two Curves

    DEFF Research Database (Denmark)

    Ravnshøj, Christian Robenhagen

    2008-01-01

    We give an explicit description of the matrix representation of the Frobenius endomorphism on the Jacobian of a genus two curve on the subgroup of l-torsion points. By using this description, we can describe the matrix representation of the Weil-pairing on the subgroup of l-torsion points...... explicitly. Finally, the explicit description of the Weil-pairing provides us with an efficient, probabilistic algorithm to find generators of the subgroup of l-torsion points on the Jacobian of a genus two curve....

  18. Damped gyroscopic effects and axial-flexural-torsional coupling using spinning finite elements for wind-turbine blades characterization

    Science.gov (United States)

    Velazquez, Antonio; Swartz, R. Andrew

    2013-04-01

    Renewable energy sources like wind are important technologies, useful to alleviate for the current fossil-fuel crisis. Capturing wind energy in a more efficient way has resulted in the emergence of more sophisticated designs of wind turbines, particularly Horizontal-Axis Wind Turbines (HAWTs). To promote efficiency, traditional finite element methods have been widely used to characterize the aerodynamics of these types of multi-body systems and improve their design. Given their aeroelastic behavior, tapered-swept blades offer the potential to optimize energy capture and decrease fatigue loads. Nevertheless, modeling special complex geometries requires huge computational efforts necessitating tradeoffs between faster computation times at lower cost, and reliability and numerical accuracy. Indeed, the computational cost and the numerical effort invested, using traditional FE methods, to reproduce dependable aerodynamics of these complex-shape beams are sometimes prohibitive. A condensed Spinning Finite Element (SFE) method scheme is presented in this study aimed to alleviate this issue by means of modeling wind-turbine rotor blades properly with tapered-swept cross-section variations of arbitrary order via Lagrangian equations. Axial-flexural-torsional coupling is carried out on axial deformation, torsion, in-plane bending and out-of-plane bending using super-convergent elements. In this study, special attention is paid for the case of damped yaw effects, expressed within the described skew-symmetric damped gyroscopic matrix. Dynamics of the model are analyzed by achieving modal analysis with complex-number eigen-frequencies. By means of mass, damped gyroscopic, and stiffness (axial-flexural-torsional coupling) matrix condensation (order reduction), numerical analysis is carried out for several prototypes with different tapered, swept, and curved variation intensities, and for a practical range of spinning velocities at different rotation angles. A convergence study

  19. Discrete Torsion, (Anti) de Sitter D4-Brane and Tunneling

    Science.gov (United States)

    Singh, Abhishek K.; Pandey, P. K.; Singh, Sunita; Kar, Supriya

    2014-06-01

    We obtain quantum geometries on a vacuum created pair of a (DDbar)3-brane, at a Big Bang singularity, by a local two form on a D4-brane. In fact our analysis is provoked by an established phenomenon leading to a pair creation by a gauge field at a black hole horizon by Stephen Hawking in 1975. Importantly, the five dimensional microscopic black holes are described by an effective non-perturbative curvature underlying a discrete torsion in a second order formalism. In the case for a non-propagating torsion, the effective curvature reduces to Riemannian, which in a low energy limit may describe Einstein vacuum in the formalism. In particular, our analysis suggests that a non-trivial space begin with a hot de Sitter brane-Universe underlying a nucleation of a vacuum pair of (DDbar)-instanton at a Big Bang. A pair of instanton nucleats a D-particle which in turn combines with an anti D-particle to describe a D-string and so on. The nucleation of a pair of higher dimensional pair of brane/anti-brane from a lower dimensional pair may be viewed via an expansion of the brane-Universe upon time. It is in conformity with the conjecture of a branes within a brane presumably in presence of the non-zero modes of two form. Interestingly, we perform a thermal analysis underlying various emergent quantum de Sitter vacua on a D4-brane and argue for the plausible tunneling geometries underlying a thermal equilibrium. It is argued that a de Sitter Schwarzschild undergoes quantum tunneling to an AdS-brane Schwarzschild via Nariai and de Sitter topological black hole.

  20. Technology development for the LISA using the UF Torsion Pendulu

    Science.gov (United States)

    Conklin, John W.; Chilton, Andrew; Olatunde, Taiwo; Apple, Stephen; Ciani, Giacomo; Mueller, Guido

    2015-08-01

    Space-based gravitational wave observatories like LISA measure picometer changes in the distances between free falling test masses separated by millions of kilometers caused by gravitational waves. A test mass and its associated sensing, actuation, charge control and caging subsystems are referred to as a gravitational reference sensor (GRS). LISA will observe gravitational wave sources ranging from super-massive black hole mergers to compact galactic binaries in the millihertz region, and LISA science has consistently been ranked in the top two for future large space missions in the last two NASA astrophysics decadal reviews. With the 2015 launch of LISA Pathfinder (LPF) and the expected detection of gravitational waves by aLIGO and/or Pulsar Timing Arrays within in the next several years, this can arguably be called the decade of gravitational waves. Following a successful demonstration of the baseline LISA GRS by LPF, the measurement principle will be carried forward, but improvements in several GRS components are possible over the next ten years that will lead to cost savings and potential noise reductions. The UF LISA group has constructed the UF Torsion Pendulum to increase U.S. competency in this critical area and to have a facility where new technologies can be developed and evaluated. This experimental facility is based on the design of a similar facility at the University of Trento, and consists of a vacuum enclosed torsion pendulum that suspends mock-ups of the LISA test masses, surrounded by electrode housings. This presentation will describe this facility, focusing on its mechanical design, capacitive sensing and electrostatic actuation systems, and overall acceleration noise performance

  1. Thermomechanical responses of nonlinear torsional vibration with NiTi shape memory alloy - Alternative stable states and their jumps

    Science.gov (United States)

    Xia, Minglu; Sun, Qingping

    2017-05-01

    The dynamic response of nonlinear torsional vibration system with phase transformable NiTi Shape Memory Alloy (SMA) wire is investigated by experiment in this paper. The thermomechanical responses of the NiTi wire as a softening nonlinear damping spring in the torsional vibration system are measured by synchronized acquisition of rotational angle and temperature under external excitation. Frequency Response Curves (FRCs) at fixed excitation amplitude and Amplitude Response Curves (ARCs) at fixed frequency are obtained in the frequency and amplitude domains respectively. It is found that, as the deformation of NiTi wire goes into the softening nonlinear phase transition region, the smooth and stable dynamic responses along one branch of FRC or ARC will gradually enter into metastable region and eventually become unstable and drastically switch to a new contrasting alternative stable state along the other branch. The jump phenomenon between the alternative stable states on the lower and upper branches of the FRC or ARC and the hysteresis between the jump-up and jump-down are identified by experiments. In addition, the effects of external disturbance (both magnitude and direction) on triggering the jumps between the alternative stable states along the two metastable branches are examined in the time domain. The stability of the nonlinear dynamic response is analyzed by the Duffing oscillator model and interpreted via the stability landscape. For the first time, we directly reveal the alternative stable states and jump phenomena of thermomechanical responses by experiments in the frequency, amplitude and time domains. The results not only show the important roles of phase transition nonlinearity in bringing multiple equilibrium states and their fast switches, but also provide a solid experimental base for the identification of metastable regions as well as further management of the undesired dynamic responses of vibration system where NiTi is used as a nonlinear

  2. Lateral-torsional response of base-isolated buildings with curved surface sliding system subjected to near-fault earthquakes

    Science.gov (United States)

    Mazza, Fabio

    2017-08-01

    The curved surface sliding (CSS) system is one of the most in-demand techniques for the seismic isolation of buildings; yet there are still important aspects of its behaviour that need further attention. The CSS system presents variation of friction coefficient, depending on the sliding velocity of the CSS bearings, while friction force and lateral stiffness during the sliding phase are proportional to the axial load. Lateral-torsional response needs to be better understood for base-isolated structures located in near-fault areas, where fling-step and forward-directivity effects can produce long-period (horizontal) velocity pulses. To analyse these aspects, a six-storey reinforced concrete (r.c.) office framed building, with an L-shaped plan and setbacks in elevation, is designed assuming three values of the radius of curvature for the CSS system. Seven in-plan distributions of dynamic-fast friction coefficient for the CSS bearings, ranging from a constant value for all isolators to a different value for each, are considered in the case of low- and medium-type friction properties. The seismic analysis of the test structures is carried out considering an elastic-linear behaviour of the superstructure, while a nonlinear force-displacement law of the CSS bearings is considered in the horizontal direction, depending on sliding velocity and axial load. Given the lack of knowledge of the horizontal direction at which near-fault ground motions occur, the maximum torsional effects and residual displacements are evaluated with reference to different incidence angles, while the orientation of the strongest observed pulses is considered to obtain average values.

  3. Kinetics and mechanism of the oxidation of some vicinal and non ...

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Chemical Sciences; Volume 115; Issue 2. Kinetics and ... Kinetics of oxidation of five vicinal and four non-vicinal diols, and two of their monoethers, by tetrabutylammonium tribromide (TBATB) has been studied. The vicinal diols ... Department of Chemistry, JNV University, Jodhpur 342 005, India ...

  4. The Critical Angle Can Override the Brewster Angle

    Science.gov (United States)

    Froehle, Peter H.

    2009-01-01

    As a culminating activity in their study of optics, my students investigate polarized light and the Brewster angle. In this exercise they encounter a situation in which it is impossible to measure the Brewster angle for light reflecting from a particular surface. This paper describes the activity and explains the students' observations.

  5. Small angle neutron scattering

    Directory of Open Access Journals (Sweden)

    Cousin Fabrice

    2015-01-01

    Full Text Available Small Angle Neutron Scattering (SANS is a technique that enables to probe the 3-D structure of materials on a typical size range lying from ∼ 1 nm up to ∼ a few 100 nm, the obtained information being statistically averaged on a sample whose volume is ∼ 1 cm3. This very rich technique enables to make a full structural characterization of a given object of nanometric dimensions (radius of gyration, shape, volume or mass, fractal dimension, specific area… through the determination of the form factor as well as the determination of the way objects are organized within in a continuous media, and therefore to describe interactions between them, through the determination of the structure factor. The specific properties of neutrons (possibility of tuning the scattering intensity by using the isotopic substitution, sensitivity to magnetism, negligible absorption, low energy of the incident neutrons make it particularly interesting in the fields of soft matter, biophysics, magnetic materials and metallurgy. In particular, the contrast variation methods allow to extract some informations that cannot be obtained by any other experimental techniques. This course is divided in two parts. The first one is devoted to the description of the principle of SANS: basics (formalism, coherent scattering/incoherent scattering, notion of elementary scatterer, form factor analysis (I(q→0, Guinier regime, intermediate regime, Porod regime, polydisperse system, structure factor analysis (2nd Virial coefficient, integral equations, characterization of aggregates, and contrast variation methods (how to create contrast in an homogeneous system, matching in ternary systems, extrapolation to zero concentration, Zero Averaged Contrast. It is illustrated by some representative examples. The second one describes the experimental aspects of SANS to guide user in its future experiments: description of SANS spectrometer, resolution of the spectrometer, optimization of

  6. Role of OH-stretch/torsion coupling and quantum yield effects in the first OH overtone spectrum of cis-cis HOONO

    Science.gov (United States)

    McCoy, Anne B.; Fry, Juliane L.; Francisco, Joseph S.; Mollner, Andrew K.; Okumura, Mitchio

    2005-03-01

    A joint theoretical and experimental investigation is undertaken to study the effects of OH-stretch/HOON torsion coupling and of quantum yield on the previously reported first overtone action spectrum of cis-cis HOONO (peroxynitrous acid). The minimum energy path along the HOON dihedral angle is computed at the coupled cluster singles and doubles with perturbative triples level with correlation consistent polarized quadruple ζ basis set, at the structure optimized using the triple ζ basis set (CCSD(T)/cc-pVQZ//CCSD(T)/cc-pVTZ). The two-dimensional ab initio potential energy and dipole moment surfaces for cis-cis HOONO are calculated as functions of the HOON torsion and OH bond length about the minimum energy path at the CCSD(T)/cc-pVTZ and QCISD/AUG-cc-pVTZ (QCISD—quadratic configuration interaction with single and double excitation and AUG-augmented with diffuse functions) level of theory/basis, respectively. The OH-stretch vibration depends strongly on the torsional angle, and the torsional potential possesses a broad shelf at ˜90°, the cis-perp conformation. The calculated electronic energies and dipoles are fit to simple functional forms and absorption spectra in the region of the OH fundamental and first overtone are calculated from these surfaces. While the experimental and calculated spectra of the OH fundamental band are in good agreement, significant differences in the intensity patterns are observed between the calculated absorption spectrum and the measured action spectrum in the 2νOH region. These differences are attributed to the fact that several of the experimentally accessible states do not have sufficient energy to dissociate to OH+NO2 and therefore are not detectable in an action spectrum. Scaling of the intensities of transitions to these states, assuming D0=82.0kJ/mol, is shown to produce a spectrum that is in good agreement with the measured action spectrum. Based on this agreement, we assign two of the features in the spectrum to Δn=0

  7. Sensitivity on materials optical properties of single beam torsional Casimir actuation

    Science.gov (United States)

    Tajik, Fatemeh; Sedighi, Mehdi; Palasantzas, George

    2017-05-01

    Here, we investigate the dynamical sensitivity of electrostatic torsional type microelectromechanical systems (MEMS) on the optical properties of interacting materials. This is accomplished by considering the combined effect of mechanical Casimir and electrostatic torques to drive the device actuation. The bifurcation curves and the phase portraits of the actuation dynamics have been analyzed to compare the sensitivity of a single beam torsional device operating between materials with conductivities that differ by several orders of magnitude. It is shown that the range of stable operation of torsional MEMS against stiction instabilities can increase by decreasing the conductivity of interacting materials. Moreover, the introduction of controlled dissipation, corresponding to a finite quality factor, in an otherwise unstable torsional system, could alter an unstable motion towards stiction to dissipative stable motion.

  8. Centre of mass in spaces with torsion free flat linear connection

    OpenAIRE

    Iliev, Bozhidar Z.

    2004-01-01

    The concept "centre of mass" is analyzed in spaces with torsion free flat linear connection. It is shown that under sufficiently general conditions it is almost uniquely defined, the corresponding arbitrariness in its definition being explicitly described.

  9. Eye torsion associated with disparity-induced vertical vergence in humans

    NARCIS (Netherlands)

    L.J. van Rijn (Laurentius); H. Collewijn (Han)

    1994-01-01

    textabstractRecently, Enright described an unexpected association between disparity-induced vertical vergence and cycloversion (conjugate eye torsion) [Enright (1992)Vision Research, 415, 279]. The present experiments were performed to verify these findings and investigate the nature of this

  10. Adnexal Incarceration in a Posterior Pelvic Peritoneal Defect Mimics Ovarian Torsion.

    Science.gov (United States)

    Jackson, Amanda M; Hope, Erica R; Phippen, Neil T

    2015-01-01

    Surgery for suspected ovarian torsion sometimes reveals unexpected sources of pelvic pain, such as internal hernias, adhesions, or anatomic defects. A 23-year-old nulligravida with Alagille syndrome was taken to the operating room with suspected ovarian torsion. Intraoperatively, the right adnexa bulged out of a right-sided, posterior peritoneal cleft that incarcerated most of the enlarged ovary. No ovarian torsion was identified. The left adnexa appeared to be normal; however, it dwelled within a left-sided posterior peritoneal cleft. The bilateral posterior peritoneal defects that housed the adnexa were likely of congenital etiology. Although adnexal incarceration is a rare finding at surgery for suspected ovarian torsion, it should be part of the differential diagnosis when evaluating acute pelvic pain. Published by Elsevier Inc.

  11. Theoretical model for the mechanical behavior of prestressed beams under torsion

    Directory of Open Access Journals (Sweden)

    Sérgio M.R. Lopes

    2014-12-01

    Full Text Available In this article, a global theoretical model previously developed and validated by the authors for reinforced concrete beams under torsion is reviewed and corrected in order to predict the global behavior of beams under torsion with uniform longitudinal prestress. These corrections are based on the introduction of prestress factors and on the modification of the equilibrium equations in order to incorporate the contribution of the prestressing reinforcement. The theoretical results obtained with the new model are compared with some available results of prestressed concrete (PC beams under torsion found in the literature. The results obtained in this study validate the proposed computing procedure to predict the overall behavior of PC beams under torsion.

  12. Contrast-enhanced ultrasonographic findings in three dogs with lung lobe torsion.

    Science.gov (United States)

    Caivano, Domenico; Birettoni, Francesco; Bufalari, Antonello; De Monte, Valentina; Angeli, Giovanni; Giorgi, Maria Elena; Patata, Valentina; Porciello, Francesco

    2016-03-01

    Lung lobe torsion is rare but life-threatening condition in the dog. Thoracic radiographs and conventional ultrasonography cannot be conclusive for the diagnosis, and computed tomography is useful but is limited by cost and availability. This report describes the findings of contrast-enhanced ultrasonography in 3 dogs with lung lobe torsion. Contrast-enhanced ultrasonography showed the absence or reduction of pulmonary vascularization secondary to twisting of the lung lobe around its bronchovascular pedicle in all three dogs. Moreover, contrast-enhanced ultrasonography distinguished partial pulmonary atelectasis from a lung lobe torsion. These preliminary results suggest that contrast-enhanced ultrasonography can improve the accuracy of conventional ultrasonography for detection of pulmonary blood flow compromise in dogs with lung lobe torsion.

  13. Low success rate of salvage surgery for testicular torsion in newborns

    DEFF Research Database (Denmark)

    Jensen, Rie Overgaard; Pedersen, Mark Ellebæk; Rasmussen, Lars

    2015-01-01

    INTRODUCTION: Testicular torsion within the first 30 days of life is rare. The treatment is controversial, and the prognosis for testis viability varies from 0 to 40% in the literature. The aim of this study was to review our institutional results for surgery for testicular torsion in the neonatal...... period with a special focus on salvage surgery. METHODS: Patient records were reviewed for all children in the age up to 30 days who were operated for testicular torsion at our hospital during the past 20 years. RESULTS: A total of 13 patients were included, two with bilateral affection. Emergency...... was only salvaged in cases with urgent surgery at symptom recognition. Cases that presented within the first day of life resulted in a non-salvageable testis despite emergency surgery. The reason may be prenatal torsion. Doctor's delay was common for this rare disease. FUNDING: not relevant. TRIAL...

  14. Twin stability in highly nanotwinned Cu under compression, torsion and tension

    DEFF Research Database (Denmark)

    Hodge, A.M.; Furnish, T.A.; Shute, C.J.

    2012-01-01

    Twin stability under four distinct mechanical loading states has been investigated for highly nanotwinned Cu containing parallel nanotwins 40 nm thick. Observed deformation-induced microstructural changes under tension, compression, tension–tension fatigue and torsion are qualitatively compared...

  15. Mannitol has a protective effect on testicular torsion: An experimental rat model.

    Science.gov (United States)

    Kurt, Omer; Yazici, Cenk Murat; Erboga, Mustafa; Turan, Cuneyt; Bozdemir, Yeliz; Akbas, Alpaslan; Turker, Polat; Aktas, Cevat; Aydin, Murat; Yesildag, Ebru

    2016-06-01

    Testicular torsion is an emergency condition that causes testicular injury. Any treatment opportunity reducing the destructive effect of testicular torsion is important for the future life of patients. In this experimental study we investigated the protective effect of mannitol on ischemia-reperfusion (I/R) injury in a rat testes torsion model. In total, 32 male Sprague Dawley rats were included. Four experimental groups included eight rats each. Group A was a sham group in which the right testis was brought out through a scrotal incision and then replaced in the scrotum without torsion. In Group B, the right testis was torsioned, by rotating 720° clockwise and fixed to the scrotum with no treatment. In Group C, the same testicular torsion process was performed with saline infusion just after testicular torsion. In group D, mannitol infusion was used just after testicular torsion. Testicles were detorsioned after 3 h and left inside for more than 2 h before orchiectomy. Histopathological, immunohistochemical, and biochemical analyses were performed. Testicular architecture was disturbed significantly in the torsion groups without mannitol infusion. However, testicular tissue structure was significantly better in the mannitol-treated group, demonstrating a protective effect. Similar findings were also shown for the proliferating cell nuclear antigen (PCNA) index and antioxidant activity; both were higher in the mannitol group than in the no-treatment and saline groups (p mannitol-treated group compared with the no treatment and saline groups (p mannitol treatment was significantly disturbed, whereas the structural disruption was considerably less in the mannitol group. Mannitol treatment also decreased reactive oxygen radical levels significantly and was able to decrease apoptosis. These results were consistent with other organ model studies that evaluated the protective effects of mannitol treatment in I/R injury. Mannitol infusion had a protective effect

  16. Torsion of a Wandering Pelvic Spleen; Acute Abdomen in a Child

    OpenAIRE

    Metin GUNDUZ; ABASIYANIK, Adnan

    2012-01-01

    Wandering spleen is an uncommon clinical entity. Acute splenic torsion of wandering spleen is a potentially fatal surgical emergency case, and its correct and early identification continues to represent a challenge especially in children. A 11 years old girl was taken to the operative room for an explorative laparotomy due to abdominal pain, tenderness, and a midabdominal mass. Preoperative computerise tomography showed a torsion of an enlarged wandering pelvic spleen which was in a serious ...

  17. Warping effect in a multifiber beam model for nonlinear analysis of reinforced concrete structures under torsion

    OpenAIRE

    CAPDEVIELLE, Sophie; GRANGE, Stephane; DUFOUR, Frederic; DESPREZ, Cedric

    2013-01-01

    A procedure is developed to account for torsional warping in the computation of fiber deformations in multifiber beam element models. The theoretical and numerical formulations to compute the cross section warping are presented and validated against axial displacements in a 3D finite element model of a column. The global nonlinear response of a column under torsion is then computed using a multifiber beam model. Differences in global and local behavior between both models with and without war...

  18. Effect of web openings on the structural behavior of RC beams subjected to pure torsion

    OpenAIRE

    Abdo Taha; Mabrouk Rasha

    2017-01-01

    In the construction of modern buildings, the presence of openings became a necessity nowadays in order to accommodate the many pipes and ducts required for the different services. On the other hand, the presence of these openings in RC beams affects their structural behavior. One important behavior that needs further study would be torsion. Currently, there are no guide lines available to analyze or design RC beams with web openings under pure torsion. Thus, the main objective of this researc...

  19. Ruptured Ectopic Pregnancy with Contralateral Ovarian Serous Cyst Adenoma Torsion: Laparoscopic Management of Double Trouble

    Science.gov (United States)

    Rajkumar, Anirudh; Rajkumar, J. S.; Guru, Venkatesan

    2016-01-01

    Adnexal torsion is responsible for 2.7% of all gynecological emergencies. Ectopic pregnancy is relatively common, occurring in 2% of all pregnancies. We report the second case of ruptured right tubal ectopic gestation with torsion of serous cystadenoma of left ovary. This was diagnosed after emergency laparoscopy done for acute abdomen. Right salpingectomy and left ovarian detorsion followed by cystectomy were done laparoscopically. PMID:27840755

  20. ACCOUNT FOR PERFORMANCE OF CORRUGATED WEB BEAMS IN THE ANALYSIS OF CONSTRAINED TORSION

    OpenAIRE

    Solovev Aleksey Vitalevich; Lukin Aleksey Olegovich; Alpatov Vadim Yurevich; Savostyanov Vadim Nikolaevich

    2012-01-01

    The authors cover the problems of the numerical analysis of corrugated web beams exposed to constrained torsion. The calculation is performed using the finite element method. Virtual solid models and software package "Lira" are employed to perform the structural analysis. The results of the comparative analysis of performance of beams that have flat and corrugated webs and that are exposed to constrained torsion are presented in the article. Corrugated web beams that have diffe...