background: elastomeric chains are commonly used in orthodontics. force decay in these materials poses clinical problems. the aim of this study was to evaluate the effects of three different mouthwashes on the force decay of orthodontic chains. materials and methods: in this experimental study, elastomeric chains with two different confi gurations were divided into eight groups (two control and...

objectives: the purpose of this study was to compare scapular kinematics during elevation phase of abduction, flexion, and scapular plane elevation phase between fifteen persons with shoulder impingement syndrome (sis) and thirteen persons without it. methods: values of scapular kinematics include scapular superior and lateral translations, upward rotation, external rotation, and posterior tipp...

This paper considers collinear lumped-parameter structures where each mass in the structure has a single degree of freedom. Specifically, we analyze the zeros and relative degree of the single-input, single-output (SISO) transfer function from the force applied to an arbitrary mass to the position, velocity, or acceleration of another mass. In particular, we show that every SISO force-to-motion...

The magnetic properties of 1 nm thick in-plane anisotropic Co ultrathin film on ZnO(0001) were investigated through successive 500 eV nitrogen-ion sputtering. Magneto-optical Faraday effects were used to observe the evolution of the ion-irradiated sample in longitudinal and perpendicular magnetic fields. The ferromagnetic phase of the initial in-plane anisotropic fcc β-Co phase transformation t...

In this article, the anti-plane deformation of an orthotropic sector with multiple defects is studied analytically. The solution of a Volterra-type screw dislocation problem in a sector is first obtained by means of a finite Fourier cosine transform. The closed form solution is then derived for displacement and stress fields over the sector domain. Next, the distributed dislocation method is em...

BACKGROUND Knee joint sagittal plane forces are a proposed mechanism of anterior cruciate ligament injury during sport movements such as sidestep cutting. Ligament force magnitudes for these movements however, remain unknown. The need to examine injury-causing events suggests elucidation via model-based investigations is possible. Using this approach, the current study determined whether sagitt...

agricultural crops and food materials exert frictional forces on agricultural machinery elements and on storage walls during their harvest, transportation, processing and storage. coefficient of friction is an important parameter to be predetermined in designing equipments and evaluating processes. an assessment of the coefficient of friction for agricultural materials is usually done through s...

impact is one of the most important subjects which always have been considered in mechanical science. nature of impact is such that which makes its control a hard task. therefore it is required to adopt a safe and secure mechanism for transferring the impact to other vulnerable parts of a structure, when it is necessary. one of the best methods of absorbing impact energy is using thin-walled tu...

As is well-known, any ordinary differential equation in one dimension can be cast as the Euler–Lagrange of an appropriate Lagrangian. Additionally, if initial autonomous, Lagrangian always chosen to time-independent. In two dimensions, however, situation more complex, and there exist systems ODEs which cannot described by this paper we display Hamiltonians describe behaviour a charged particle ...