An experimental investigation of the aerodynamics of a NACA 64A010 airfoil-flap combination with and without flap oscillations. Part 1: Steady-state characteristics

A NACA 64A010 airfoil with a sealed-gap 1/4-chord flap was tested between splitter plates in the NASA Ames 11- by 11-Foot Transonic Wind Tunnel at Mach numbers from 0.50 to 0.85, and Reynolds numbers based on chord from 3 to 13 million. Although the main purpose of the test was to obtain unsteady pressure data with the flap oscillating, no unsteady data are presented in this paper. The steady-state data are presented and compared with other test data to provide a basis for evaluating the results. Pressure data at two span stations are used to deduce early boundary-layer transitions at the midspan at higher Mach numbers, angles of attack, and flap angles. The effects of flap angle on pressures, normal force, pitching moment, and hinge moment are also presented in the report. Mach number errors caused by the splitter-plate configuration and the angle of attack are evaluated using pressure measurements near the floor and ceiling of the wind tunnel

Alternative project delivery in rural Alaska: experiences, quality and claims

Master's Project (M.S.) University of Alaska Fairbanks, 2015The popularity of alternative project delivery systems has expanded beyond the private sector and into the public sector. Alaska embodies unique challenges that may present obstacles while using alternative project delivery systems. This analysis will provide an understanding of alternative project delivery systems in Alaska and how local experiences, quality and claims are affected. Alaska's unique characteristics present both challenges and opportunities for implementing alternative project delivery systems. This report begins with a discussion of experiences from several rural Alaska projects, and how alternative project delivery systems can be utilized. Some impacts that alternative project delivery systems have on quality are then presented, including a perspective on quality and recommendations for achieving customer satisfaction. A treatment of construction claims is then provided, followed by conclusions and recommendations for stakeholders in selecting an appropriate project delivery system. Alternative project delivery systems were researched by means of scholarly literature reviews, professional interviews and seminars. The report of these findings is intended to provide owners and contractors with a concise presentation of the challenges and advantages for using alternative project delivery systems in Alaska

Complex Saddles in Two-dimensional Gauge Theory

We study numerically the saddle point structure of two-dimensional (2D) lattice gauge theory, represented by the Gross-Witten-Wadia unitary matrix model. The saddle points are in general complex-valued, even though the original integration variables and action are real. We confirm the trans-series/instanton gas structure in the weak-coupling phase, and identify a new complex-saddle interpretation of non-perturbative effects in the strong-coupling phase. In both phases, eigenvalue tunneling refers to eigenvalues moving off the real interval, into the complex plane, and the weak-to-strong coupling phase transition is driven by saddle condensation.Comment: 4+4 pages RevTeX, 9 figures; v2: version published in PR

A practical experience with independent verification and validation

One approach to reducing software cost and increasing reliability is the use of an independent verification and validation (IV & V) methodology. The Software Engineering Laboratory (SEL) applied the IV & V methodology to two medium-size flight dynamics software development projects. Then, to measure the effectiveness of the IV & V approach, the SEL compared these two projects with two similar past projects, using measures like productivity, reliability, and maintain ablilty. Results indicated that the use of the IV & V methodology did not help the overall process nor improve the product in these cases