Bidirectional cargo transport by molecular motors in cells is a complex phenomenon in which the cargo (usually a vesicle) alternately moves in retrograde and anterograde directions. In this case, teams of oppositely pulling motors (e.g., kinesin and dynein) bind to the cargo, simultaneously, and 'coordinate' their activity such that the motion consists of spells of positively and negatively dir...

Wind tunnel experiments have shown that bumps on the leading edge of model humpback whale flippers cause them to "stall" (i.e., lose lift dramatically) more gradually and at a higher angle of attack. Here we develop an aerodynamic model which explains the observed increase in stall angle. The model predicts that as the amplitude of the bumps is increased, the lift curve flattens out, leading to...

Wind tunnel experiments were conducted to understand boundary layer separation control on airfoils. The objective of this research was to better implement flow control strategies with single dielectric barrier discharge (SDBD) plasma actuator designs for airfoils that exhibit both leading and trailing edge stall characteristics at realistic flight speeds and Reynolds numbers. The NASA energy ef...

Ribosome stalling on mRNAs can decrease protein expression. To decipher ribosome kinetics at stall sites, we induced ribosome stalling at specific codons by starving the bacterium Escherichia coli for the cognate amino acid. We measured protein synthesis rates from a reporter library of over 100 variants that encoded systematic perturbations of translation initiation rate, the number of stall s...

A multidisciplinary research effort that combines aerodynamic modeling and gain-scheduled control design for aircraft flight at post-stall conditions is described. The aerodynamic modeling uses a decambering approach for rapid prediction of post-stall aerodynamic characteristics of multiple-wing configurations using known section data. The approach is successful in bringing to light multiple so...

To reduce the negative impacts of stall and surge on compressor performance, a novel combined casing treatment (CCT) structure with axial skewed slots injection groove is proposed in this paper. The aerodynamic as well mechanisms loss generation, transonic NASA Rotor 67 are investigated numerically. simulation results indicate that, compared individual method, CCT works effectively regard to op...

In this short paper we briefly describe the results of analyzing a large-scale data set of actual YouTube stall patterns collected world-wide as part of Columbia University’s YouSlow project, and how we used it to create a simple model for generating realistic stalling patterns with a given number of stalls, a given average stall duration, and a pattern structure (describing the relative length...

Unsteady numerical simulation of single passage was carried out on NASA Rotor 35 to study the influence radial inclined angle self-circulation casing treatment (SCT) performance and stability a transonic compressor at 100% design speed. The angles were set 0°(D0), °(D30) 60°(D60), respectively. calculated result indicates an increase in stall margin improvement (SMI) efficiency (DEI) as increas...

An unsteady two-dimensional finite-volume solver was developed based on Van Leer’s flux splitting algorithm in conjunction with “Monotonic Upstream Scheme for Conservation Laws (MUSCL)” limiters and the two-layer Baldwin-Lomax turbulence model was also implemented. To validate the solver, two test cases were prepared and the computed results had good agreements with reference data. The rotating...