Beckmann's theory of scattering from rough surfaces is applied to obtain, from the experimental veiling glare functions, a diffuser that when placed at the pupil plane would produce the same scattering halo as the ocular media. This equivalent diffuser is introduced in a schematic eye model, and its influence on the point-spread function and the modulation-transfer function of the eye is analyzed.

Regions of positive slope in the pressure-discharge characteristics can result in a reduction or even lack of damping of system instabilities. They are therefore one of the major concerns in design and operation of centrifugal pumps as they are limiting the admissible operating range. The considered preliminary hydraulic design of an industrial double suction pump of medium specific speed ν = 0...

SUMMARY The aerodynamic design and experimental performance of a centrifugal compressor designed for a pressure ratio of 6.5 and a specific speed of 68 are described, The compressor consisted of a radially-vaned impeller and a transonic, vaned radial diffuser. At design speed a peak overall total-to-total isentropic efficiency of 0.746 was achieved at the maximum pressure ratio of 5.9, rising t...

In this paper, we report a simple technique for the fabrication of planar valveless micropumps. The technique utilizes MEMS fabrication methods by using a double sided etch technique. Instead of using several masks and process steps, an anisotropic wet etch technique at both sides of a silicon substrate is implemented at the same time for creating the pump membrane and the diffuser/ nozzle elem...

A new approach to the evaluation of the performance of diffusers is presented. It is assumed that part of the juice in bagasse is easily extracted, by mill o r diffuser, and attention is therefore focussed on the remaining tightly-held or bound juice. This "difficult juice" is defined according to an analytical method. Preliminary results on the performance of diffusers, based on the extraction...

Personal electronic devices such as cell phones and tablets continue to decrease in size while the number of features and add-ons keep increasing. One particular feature of great interest is an integrated projector system. Laser pico-projectors have been considered, but the technology has not been developed enough to warrant integration. With new advancements in diode technology and MEMS device...

Air supply volumes and velocities in cleanrooms are monitored by airflow measuring hoods and anemometers but these measuring methods can be inaccurate if used incorrectly. It is demonstrated in this article that measuring hoods are accurate if the air supply passes evenly out of the hood, as occurs when the air volume is measured from a four-way diffuser or no air supply diffuser. However, when...

The performance of a diffuser in a pump stage depends on its configuration and placement within the stage. The influence of vane shape on the hydrodynamic performance of a diffuser has been studied. The goal of this effort has been to improve the performance of a pump stage by optimizing the shape of the diffuser vanes. The shape of the vanes was defined using Bezier curves and circular arcs. S...

A general theory is presented of optimum diffusion via multi-dimensional 2point transforms over the ring of integers modulo a power of 2. This theory, which makes extensive use of graph-theoretic techniques, establishes the optimality of the transform diffuser used in the cipher SAFER+. A complete characterization is given of the matrix that describes an optimum transform diffuser. Finally, som...