Courage

In this chapter, DeYoung looks at the culturally and historically recognized virtue of courage. She specifically questions how we should think of all the pictures of courage and where we might look for Christlike examples of courage. To do this, DeYoung explores courage as it relates to fear and love and then delves into how courage can be a Christian practice

Optimum lattice arrangement developed from a rigorous analytical basis

The spanwise vortex-lattice arrangement is mathematically established by lattice solutions of the slender wing which are shown to be analogous to the chordwise vortex-lattice thin wing solution. Solutions for any number N of panels wing theory lift and induced drag and thin wing theory lift and moment are predicted exactly. As N approaches infinity, the slender wing elliptic spanwise loading and thin wing cotangent chordwise loading are predicted, which proves there is mathematical convergence of the vortex-lattice method to the exact answer. Based on this planform spanwise lattice arrangement, an A-vortex-lattice spanwise system is developed for an arbitrary aspect ratio A. This A-lattice has the optimum characteristic of predicting lift accurately for any value of N

Historical evolution of vortex-lattice methods

A review of the beginning and some orientation of the vortex-lattice method were given. The historical course of this method was followed in conjunction with its field of computational fluid dynamics, spanning the period from L.F. Richardson's paper in 1910 to 1975. The following landmarks were pointed out: numerical analysis of partial differential equations, lifting-line theory, finite-difference method, 1/4-3/4 rule, block relaxation technique, application of electronic computers, and advanced panel methods

Practicing Hope

In this essay, I consider how the theological virtue of hope might be practiced. I will first explain Thomas Aquinas’s account of this virtue, including its structural relation to the passion of hope, its opposing vices, and its relationship to the friendship of charity. Then, using narrative and character analysis from the film The Shawshank Redemption, I examine a range of hopeful and proto-hopeful practices concerning both the goods one hopes for and the power one relies on to attain those goods. In particular, I show how the film’s picture of the role friends and friendship play in catalyzing hope is a compelling metaphor for Christian hope’s reliance on Go

Safety, soundness, and the evolution of the U.S. banking industry

Although the banking system appears to be safer and sounder today than it was two decades ago, new risk challenges have arisen that could not have been anticipated in the 1980s. This article outlines the fundamental structural changes in the U.S. commercial banking industry since then. ; The author's strategic analysis of the current state of the industry compares the "transactions banking" business model practiced by large financial companies to the more traditional relationship-based banking business model. In particular, the author focuses on the different production technologies, product mixes, strategic behaviors, and risk-return trade-offs that characterize these two opposite approaches. In closing, the article discusses what these new developments may mean for the industry's ongoing safety and soundness.Banks and banking ; Bank supervision

Aircraft control by propeller cyclic blades

A theory is developed for aircraft control obtained from the propeller forces and moments generated by blade angle variation during a blade revolution. The propeller blade is pitched harmonically one cycle per propeller revolution which results in vehicle control forces and moments, termed cyclic-control. Using a power series respresentation of an arbitrary function of cyclic-blade angle, cyclic-control theory is developed which leads to exact solutions in terms of derivatives of steady-state thrust and power with respect to blade angle. An alternative solution, when the cyclic-blade angle function is limited to a sinusoidal cycle, is in terms of Bessel functions. An estimate of non-steady azimuth angle change or lag is presented. Cyclic-control analysis applied to the counter-rotating propeller shows that control forces or moments can be uniquely isolated from each other. Thus the dual rotor, in hovering mode, has propulsion without rotor tilt or moments, or, when in propeller mode at the tail of an air ship or submarine, vehicle control with no vehicle movement. Control isolation is also attainable from three or more propellers in-line

The Internet's place in the banking industry

Internet ; Electronic commerce

Overview and future direction for blackbody solar-pumped lasers

A review of solar-pumped blackbody lasers is given which addresses their present status and suggests future research directions. The blackbody laser concept is one system proposed to scale to multimegawatt power levels for space-to-space power transmissions for such applications as onboard spacecraft electrical or propulsion needs. Among the critical technical issues are the scalability to high powers and the laser wavelength which impacts the transmission optics size as well as the laser-to-electric converter at the receiver. Because present blackbody solar-pumped lasers will have laser wavelengths longer than 4 microns, simple photovoltaic converters cannot be used, and transmission optics will be large. Thus, future blackbody laser systems should emphasize near visible laser wavelengths

Potential of solar-simulator-pumped alexandrite lasers

An attempt was made to pump an alexandrite laser rod using a Tamarak solar simulator and also a tungsten-halogen lamp. A very low optical laser cavity was used to achieve the threshold minimum pumping-power requirement. Lasing was not achieved. The laser threshold optical-power requirement was calculated to be approximately 626 W/sq cm for a gain length of 7.6 cm, whereas the Tamarak simulator produces 1150 W/sq cm over a gain length of 3.3 cm, which is less than the 1442 W/sq cm required to reach laser threshold. The rod was optically pulsed with 200 msec pulses, which allowed the alexandrite rod to operate at near room temperature. The optical intensity-gain-length product to achieve laser threshold should be approximately 35,244 solar constants-cm. In the present setup, this product was 28,111 solar constants-cm