Twist Angle
Mostrando 1-12 de 32 artigos, teses e dissertações.
-
1. Impact response of functionally graded conical shells
This paper presents low velocity impact response of functionally graded pretwisted conical shells. The modified Hertzian contact law which accounts for permanent indentation is utilized to compute the contact force and other impact parameter. The time dependent equations are solved by Newmark's time integration scheme. An eight noded isoparametric quadratic
Lat. Am. j. solids struct.. Publicado em: 2015-01
-
2. Projeto, construção e teste de uma máquina de torção / Design, construction and testing of a torsion machine
Durante o cumprimento deste trabalho foi criado o projeto de um equipamento para efetuar o ensaio de torção seguindo padrões de normas disponíveis para o teste. O equipamento foi construído e testado nos últimos dois anos, e o principal objetivo de tal desenvolvimento foi obter um aparelho de baixo custo com capacidade de realizar ensaios com boa preci
Publicado em: 2011
-
3. Construção e testes de máquina de ensaio de torção plástica para levantamento do comportamento plástico de metais
A computerized prototype machine for cold torsion testing has been developed, constructed and tested in the Laboratory of Metal Forming at UDESC (University the State the Santa Catarina) - Joinville. The equipment consists of a horizontal torsion machine, employing an electric motor, a wheel, a horizontal axle and a control and acquisition data system. The g
Publicado em: 2004
-
4. The effect of the superhelicity on the double helix twist angle in DNA.
An attempt to estimate the relative contributions of twisting and bending to the free energy of superhelix formation from the relaxed DNA is undertaken. The extent of teritiary ordering (number of DNA axis turns tau) and that of secondary ordering (duplex twist angle beta) have been taken as thermodynamical parameters, which characterize the state of the sup
-
5. The ten helical twist angles of B-DNA.
On the assumption that the twist angles between adjacent base-pairs in the DNA molecule are additive a linear system of 40 equations was derived from experimental measurements of the total twist angles for different pieces of DNA of known sequences. This system of equations is found to be statistically consistent providing a solution for all ten possible twi
-
6. A sequence analysis system encompassing rules for DNA helical distortion.
Recently, it has been shown by Calladine (1982) and Dickerson (1983) that DNA distortions due to steric clashes between opposing purines and pyrimidines can be quantitated based upon four sum functions. The distortions involve helical twist, roll, torsion angle variations and propeller twist. It is the contention of the authors that these perturbations in st
-
7. A molecular mechanical model to predict the helix twist angles of B-DNA.
We present here a model for the prediction of helix twist angles in B-DNA, a model composed of a collection of torsional springs. Statistically averaged conformational energy calculations show that, for a specified basepair step, the basepair-basepair conformational energy is quadratically dependent on the helix twist angle, so the calculations provide the s
-
8. DNA bending: the prevalence of kinkiness and the virtues of normality.
DNA bending in 86 complexes with sequence-specific proteins has been examined using normal vector plots, matrices of normal vector angles between all base pairs in the helix, and one-digit roll/slide/twist tables. FREEHELIX, a new program especially designed to analyze severely bent and kinked duplexes, generates the foregoing quantities plus local roll, til
-
9. Identification of a DNA structural motif that includes the binding sites for Sp1, p53 and GA-binding protein.
We have analyzed predicted helical twist angles in the 21-bp repeat region of the SV40 genome, using a semi-empirical model previously shown to accurately predict backbone conformations. Unexpectedly, the pattern of twist angles characteristic of the six GC-boxes is repeated an additional five times at positions that are regularly interspersed with the six G
-
10. Computer graphics program to reveal the dependence of the gross three-dimensional structure of the B-DNA double helix on primary structure.
Programs are presented to plot the gross three-dimensional structure of the DNA double helix with the base sequence as input information. The rules that determine the overall structure of the double helix are those that predict the dependence of local helix parameters (specifically, helix twist angle and relative basepair roll angle) on sequence. For this pu
-
11. New insights into DNA triplexes: residual twist and radial difference as measures of base triplet non-isomorphism and their implication to sequence-dependent non-uniform DNA triplex
DNA triplexes are formed by both isomorphic (structurally alike) and non-isomorphic (structurally dissimilar) base triplets. It is espoused here that (i) the base triplet non-isomorphism may be articulated in structural terms by a residual twist (Δt°), the angle formed by line joining the C1′…C1′ atoms of the adjacent Hoogsteen or reverse Hoogsteen (
Oxford University Press.
-
12. X-ray scattering from the superhelix in circular DNA.
This communication presents measurements, made with a newly constructed position-sensitive detector, of the small-angle x-ray scattering from the first-order superhelix of native COP608 plasmid DNA. This instrument measures intensities free of slit effects and provides good resolution in the region of interest. The reported observations, made both in the pre