The fine structure of Bombyx mori silk fibroin was investigated by electron microscopy and X-ray diffraction techniques. Examination of silk fibers fragmented with ultrasonic radiation and negatively stained revealed the presence of ribbon-like filaments of well-defined lateral dimensions. Analysis of the breadths of the equatorial reflections in the X-ray diffraction pattern of fibroin yielded...

The picosecond holographic grating generation and detection of ultrasonic waves are described. Two mechanisms, a heating mechanism and a stimulated Brillouin scattering mechanism, are described. These permit the generation of tunable ultrasonic waves in the MHz to GHz range. It is demonstrated that the two mechanisms can be distinguished by the distinct time dependences of the diffraction of a ...

The objectives of this work were (i) to validate electrical zone sensing and laser diffraction for the analysis of primary particle size in the case of inhalation dry powders and (ii) to study the influence of the aggregation state of the powder on the sizing techniques. Free-flowing dry powders were prepared by spray-drying with a combination of albumin, lactose, and dipalmitoylphosphatidylcho...

the dried nitrate-urea gels exhibit the combination of autoicatatric combustion behavior and ultrasonic, whichcan be used to synthesize the nanocatalyst ferrite powders. cu and ni unites nanocatalyst powders sithcomposition of caned], and nife204 were synthesized by a sol-gel auto catalnic combustion process. themolar ratio between metal ions and urea was 11.2. the sob gel process was done at 8...

This work has three goals. The first is to derive closed-form spatially averaged two-way diffraction corrections for focused piston transducers operating in pulsed mode. The goal is attained by (i) establishing that the arccos and Lommel diffraction formulations form an approximate Fourier transform pair and (ii) exploiting this newly established Fourier equivalence in rigorous and original der...

Time-of-flight diffraction method (ToFD) is an amplitude-independent sizing method which is based on the measurement of time-of-flight of defect tip diffracted waves. Although ToFD can measure through-wall length of defect accurately, this method is not capable of measuring horizontal defect size. In this paper, a new ToFD method for evaluating horizontal planar defects is presented. The finite...

in recent years many research works have been carried out on anti-corrosive nanocomposites coatings containing mineral reinforcements. the most important criteria in these attempts are polymerization method and the type of matrix and reinforcement of nanocomposites. in this regard, the physical and mechanical properties of the polymers in which a small amount of filler is used can be improved. ...

There are several techniques that may be used in the tomographic imaging of structural and geotechnical systems. X-ray tomography and ultrasonic imaging are two of the extreme techniques as functions of resolution and costs. On one hand, X-ray tomography allows the collection of high-resolution images in small specimens that may be removed from the structure. The application of X-rays in the fi...