We would like to welcome our readers to the twenty-eighth issue of 49 th Parallel and our second of 2012. In the last few months there have been some exciting developments at the journal and we hope that 49 th Parallel will continue to flourish in the future. We would like to welcome our new Articles Editor, Galateia Demetriou, to the 49 th Parallel team. Galateia is a second year doctoral rese...

THE RESPONSE of hitherto known practical forms of seismographs depends upon the relative motion of a pendulum and the moving ground to which ~ts supporting structure is fastened. The various kinds of seismographs differ in the type of pendulum used, such as gravity, spring, torsion, and/or they differ in the type of magnifying and recording elements which they employ. They all measure or indica...

Beijing’s mountainous areas have an important ecological significance because they are ecological conservation and water source protection areas of Beijing. The impact of precipitation on the vegetation coverage of Beijing’s mountainous areas is qualitatively analyzed using multi-temporal Landsat images obtained during the last 20 years. Firstly, the influence of external factors, such as pheno...

Hinge-based Ankle Foot Orthosis (HAFO) is one of the most common non-surgical solutions for the foot drop. In conventional HAFOs, the ankle joint is almost locked, and plantar flexion is restricted due to the high stiffness of the hinge mechanism. This often leads to a rigid walking gate cycle, poor muscle activity, and muscle atrophy. Since the ankle torque-angle loop has a non-linear profile,...

In this paper, the nonlinear conjugate map is applied based on the conjugate Hasofer-Lind and Rackwitz- Fiessler (CHL-RF) method to evaluate the reliability index using the first order reliability method of the embedded nanocomposite beam, which is made of a polymer reinforced with carbon nanotubes (CNTs). The structure is simulated with the Timoshenko beam model. The Mori-Tanaka model is appli...

in this paper, the nonlinear conjugate map based on the conjugate hasofer-lind and rackwitz- fiessler (chl-rf) method is applied to evaluate the reliability index using first order reliability method of the embedded noanocompsite beam, which is made from polymer reinforced with carbon nanotubs (cnts). the structure is simulated with timoshenko beam model. the mori-tanaka model is applied for ca...

Abstract We consider the relative motion of system two masses connected by a spring. analyze it in range Hooke’s law and show that equations are nonlinear once equilibrium length spring is nonzero. Although way deriving standard classical mechanics solving them complicated interesting problem mathematical physics. The analysis leads naturally to elliptic integrals. obtain complete formulas an i...

Solitons are a unique class of pulse-shaped waves that propagate in nonlinear dispersive media. In the course of propagation, they maintain spatial confinement of wave energy within the pulse shape without dispersion and exhibit remarkable nonlinear dynamics. Solitons are found throughout nature where fine balance between nonlinearity and dispersion is achieved. Dispersion alone would flatten o...

Quartz resonators in contact with metal-covered spheres have been used to study the tribology of micron-sized metal-metal contacts at high speed (1 m/sec and high frequency (12 MHz), while maintaining a shear amplitude in the nanometer range. The data aquisition is based on ring-down experiments, where the electrical excitation is periodically interrupted and the free decay of the oscillation i...

Implant placement under soft tissues operation is described. In this operation tissues can reach such deformations that nonlinear properties are appeared. A mass-spring model modification for modeling nonlinear tissue operation is developed. A method for creating elasticity module using splines is described. For Poisson ratio different stiffness for different types of springs in cubic grid is u...