The practical problem. In many practical situations, it is extremely important to be able to detect hidden cracks (and other possible faults) in aerospace and other structures. One way of testing the structural integrity of such structures is by using ultrasonic waves. For thin plates, Lamb waves (which direct the energy along the plate) are especially useful. To use these waves, we set up a tr...

An algorithm is presented for assembling tiles into a variable spaced grating, the one-dimensional analog of a Fresnel zone plate. The algorithm supports multi-level gratings. The x-ray properties of such a grating, assumed to be constructed from DNA are estimated, leading to the conclusion that thick structures may be useful for intermediate energy x rays, but that thin structures for soft x r...

Reliable and simple techniques for rapid assembly and patterning of colloid architectures advance the discovery and implementation of such nanomaterials. This work demonstrates rapid electrokinetic two-dimensional assembly of colloidal structures guided by the geometry of thin film heaters within a parallel-plate device. This system is designed to enable either independently addressable or mass...

Navigation for neurosurgical procedures must be highly accurate. Often small structures are hardly seen on pre-operative scans. Fitting a 3D electronic neuroanatomical atlas on the data assists with the localization of small structures and dim outlines. During surgery also brainshifts occurs. With intra-operative MRI the preoperative MRI can be warped to the real 3D situation. The paper describ...

We study the dynamical regime of wave turbulence of a vibrated thin elastic plate based on experimental and numerical observations. We focus our study on the strongly nonlinear regime described in a previous Letter by Yokoyama and Takaoka. At small forcing, a weakly nonlinear regime is compatible with the weak turbulence theory when the dissipation is localized at high wave number. When the for...

We report a new approach to adjust and improve nanostructures after their initial fabrication, which can reduce the trench width and hole diameter to sub-10 nm, while smoothing edge roughness and perfecting pattern shapes. In this method, termed pressed self-perfection by liquefaction (P-SPEL), a flat guiding plate is pressed on top of the structures (which are soften or molten transiently) on ...

A microactuator technology utilizing magnetic thin films and polysilicon flexures is applied to torsional micro-structures. These structures are constructed in a batch-fabrication process that combines electroplating with conventional IC-lithography, materials, and equipment. A microactuated mirror made from a 430x130x15 µm 3 nickel-iron plate attached to a pair of 400x2.2x2.2 µm 3 polysilicon ...

in design and optimization process of laminated composite structures, the number of layers, layer angles, stacking sequence, material types and etc should be specified. each of aforesaid parameters can be applied as a design variable. in this paper the target is to minimize the weight of laminated composite pin loaded structures. the laminated composite structures are designed based on the load...

Performing a craniotomy will cause brain tissue to shift. As a result of the craniotomy, the accuracy of stereotactic localization techniques is reduced unless the brain shift can be accurately measured. If an ultrasound probe is tracked by a 3D optical tracking system, intraoperative ultrasound images acquired through the craniotomy can be compared to pre-operative MRI images to quantify the s...

The qualitative and quantitative comparison of preand postoperative image data is an important possibility to validate computer assisted surgical procedures. Due to deformations after surgery a non-rigid registration scheme is a prerequisite for a precise comparison. Interactive landmark-based schemes are a suitable approach. Incorporation of a priori knowledge about the anatomical structures t...