This study presents an edge detection and speckle tracking (EDST) based algorithm to calculate distensibility as percentage of change of vessel diameter during cardiac cycles. Canny edge detector, Vandermonde matrix representation, Kanade Lucas Tomasi algorithm with pyramidal segmentation, and penalized least squares technique identifies the vessel lumen edge, track the vessel diameter, detrend the signal and find peaks and valleys when the vessel is fully distended or contracted. An upper extremity artery from 10 patients underwent an ultrasound examination as part of preoperative evaluation before arteriovenous fistula surgery. Three studies were performed to evaluate EDST with automatic peak and valley selection versus manual speckle selection of expert users using manual peak and valley selection. Results demonstrate the effectiveness of the proposed methodology, to obtain comparable results as those obtained by expert-users, and considerably reducing the variability associated with external factors such as excessive motion, fluctuations in stroke volume, beatto-beat blood pressure changes, breathing cycles, and armtransducer pressure.

The famous Lorenz system is studied and analyzed for a particular set of parameters originally proposed by Lorenz. With those parameters, the system has a single globally attracting strange attractor, meaning that almost all initial conditions in its 3D state space approach the attractor as time advances. However, with a slight change in one of the parameters, the chaotic attractor coexists with a symmetric pair of stable equilibrium points, and the resulting tri-stable system has three intertwined basins of attraction. The advent of 3D printers now makes it possible to visualize the topology of such basins of attraction as the results presented here illustrate.

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3D printing, a kind of emerging technology in additive manufacturing (AM), has been applied in many areas and aroused significant interests in academia and industry, for it promotes the development of democratizing design and manufacturing at lower overall costs. However, most 3D printers use open-loop stepper motor in their extrusion systems, which leads to unstable printing quality because it cannot change extrusion speed accordingly when manufacturing defects occur. Addressing this problem, this paper focuses on improving 3D printer feeding motor's ability of responding to inconstant filament diameter and provides a feasible solution including a conceptual design for feeding motor adaptive control as well as the possible printer configurations. In addition, by comparing series simulation results between the performance of stepper motor and servomotor operating within 3D printer feeding system, we conclude that servomotor can achieve and stabilize at a target value in a shorter time, thus inconstant extrusion caused by filament diameter variations and the slippage can be solved.