Method of welding joint in closed vessel improves quality of seam

To facilitate welding of closed vessels, a metal backup strip is used at the junction inside the vessel. After welding from the outside, this strip is dissolved by a chemically reactive solvent poured through a filler hole into the vessel

Clinical and magnetic resonance imaging features of idiopathic oculomotor neuropathy in 14 dogs: Canine Idiopathic Oculomotor Neuropathy

Ophthalmoplegia/ophthalmoparesis (internal, external, or both) has been reported in dogs secondary to neoplasia affecting the oculomotor nerve and is usually given a poor prognosis. The purpose of this retrospective study was to describe the clinical findings, magnetic resonance imaging (MRI) findings, management, outcome, and follow-up in a group of canine cases with idiopathic oculomotor neuropathy. Inclusion criteria included cases with ophthalmoplegia/ophthalmoparesis (internal, external or both) as sole neuroophthalmologic signs, complete ophthalmic and neurologic examination, head MRI, and a minimum follow-up period of 1 year. Dogs with progressive neurological signs not related to oculomotor neuropathy were excluded. Fourteen cases met the inclusion criteria. All cases were unilaterally affected. Magnetic resonance imaging showed equivocal enlargement of the oculomotor nerve in three cases, mild enlargement in five, and marked enlargement in six. Contrast enhancement was present in 12 cases, being marked in six. When present, the contrast enhancement was focal in eight cases and diffuse in four. The median follow-up time was 25 months. External ophthalmoparesis improved in seven cases, five cases under no treatment and two under systemic corticosteroid therapy. The clinical signs in the other seven cases remained unchanged. Idiopathic oculomotor neuropathy should be included as a differential diagnosis in dogs presenting with unilateral ophthalmoplegia/ophthalmoparesis (internal, external, or both) with the absence of other neurologic and ophthalmic signs, and with the MRI findings restricted to the oculomotor nerve. Idiopathic oculomotor neuropathy has a good prognosis as the clinical signs do not deteriorate and they can improve without treatment

Aerodynamic characteristics of a 1/6-scale powered model of the rotor systems research aircraft

A wind-tunnel investigation was conducted to determine the effects of the main-rotor wake on the aerodynamic characteristics of the rotor systems research aircraft (RSRA). For the investigation, a 1/6-scale model with a four-blade articulated main rotor was used. Tests were conducted with and without the main rotor. Both the helicopter and the compound helicopter were tested. The latter configuration included the auxiliary thrust engines and the variable-incidence wing. Data were obtained over ranges of angle of attack, angle of sideslip, and main-rotor collective pitch angle at several main-rotor advance ratios. Results are presented for the total loads on the airframe as well as the loads on the rotor, the wing, and the tail. The results indicated that without the effect of the rotor wake, the RSRA had static longitudinal and directional stability and positive effective dihedral. With the effect of the main rotor and its wake, the RSRA exhibited longitudinal instability but retained static directional stability and positive effective dihedral

Dynamic stability characteristics of the combination space shuttle orbiter and ferry vehicle

Subsonic forced-oscillation tests of a 0.015 scale model of the space shuttle orbiter/747 ferry vehicle were conducted in the Langley high speed 7- by 10-foot tunnel at Mach numbers of 0.2, 0.4, and 0.5 for angles of attack up to 12 deg. Tests were made of the basic 747 airplane, of the modified 747 (tip fins and struts added), of the ferry configuration, (747 plus orbiter at an incidence angle of 3 deg), and of the approach and landing test configuration (747 plus orbiter at an incidence angle of 6 deg)

Aerodynamic characteristics of a powered tilt-proprotor wind tunnel model

An investigation was conducted in the Langley V/STOL tunnel to determine the performance, stability and control, and rotor-wake interaction effects of a powered tilt-proprotor aircraft model with gimbal-hub rotors. Tests were conducted at representative flight conditions for hover, helicopter, transition, and airplane flight. Force and moment data were obtained for the complete model and for each of the two rotors. In addition to wind-speed variation, the angle of attack, angle of sideslip, rotor speed, rotor collective pitch, longitudinal cyclic pitch, rotor pylon angle, and configuration geometry were varied. The results, presented in graphical form, are available in tabular form to facilitate the validation of analytical methods of defining the aerodynamic characteristics of tilt-proprotor configurations

China's Rise: Challenges and Opportunities

The global economic crisis has made clear China's importance and expanding role on the world stage. China's Rise: Challenges and Opportunities, explains actions both China and the United States can take that will not only maximize the opportunities for China's constructive integration into the international community but also help form a domestic consensus that will provide a stable foundation for such policies. This book is unique in that it analyzes the authoritative data on China's economy, foreign and domestic policy, and national security. China is confronting domestic challenges that are in many ways side effects of its economic successes, while simultaneously trying to take advantage of the foreign policy benefits of those same successes. * The book from The China Balance Sheet Project, a joint, multiyear project of the Center for Strategic and International Studies and the Peterson Institute, discusses China's military modernization, China's increasing soft power influence in Asia and around the world, China's policy toward Taiwan, domestic political development, Beijing's political relations with China's provincial and municipal authorities, corruption and social unrest, rebalancing China's economic growth, the exchange rate controversy, energy and the environment, industrial policy, trade disputes, and investment issues. The paperback book features a new introduction that addresses events since fall of 2008 and provides context for the book in light of those events.

Aerodynamic characteristics of a 1/6-scale model of the rotor systems research aircraft with the rotors removed

A wind-tunnel investigation was conducted to refine the aerodynamic characteristics of the rotor systems research aircraft. For the investigation, a 1/6-scale model without a main rotor or a tail rotor was used. The model provided the capability for testing different engine nacelle sizes, engine pylon fairings, and tail configurations. The engine thrust effects were modeled by small engine simulators (fans). Data were obtained primarily over an angle-of-attack range from -13 deg to 13 deg at several values of sideslip. Stability characteristics and control effectiveness were investigated. The model with the scaled engine nacelles and the combination T-tail and lower horizontal tail displayed longitudinal and lateral-directional stability. Results show that by reducing the horizontal or vertical-tail span the longitudinal stability is decreased. Reducing the engine nacelle size increases the static stability of the model. Effective dihedral is essentially zero at 0 deg angle of attack and 0 deg wing incidence

Robust CNOT gates from almost any interaction

There are many cases where the interaction between two qubits is not precisely known, but single qubit operations are available. In this paper we show how, regardless of an incomplete knowledge of the strength or form of the interaction between two qubits, it is often possible to construct a CNOT gate which has arbitrarily high fidelity. In particular, we show that oscillations in the strength of the exchange interaction in solid state Si and Ge structures are correctable.Comment: 5 pages, 2 figure

China's Rise: Challenges and Opportunities

China has emerged as an economic powerhouse (projected to have the largest economy in the world in a little over a decade) and is taking an ever-increasing role on the world stage. China's Rise: Challenges and Opportunities will help the United States and the rest of the world better comprehend the facts and dynamics underpinning China's rise--an understanding that becomes more and more important with each passing day. Additionally, the authors suggest actions both China and the United States can take that will not only maximize the opportunities for China's constructive integration into the international community but also help form a domestic consensus that will provide a stable foundation for such policies. Filled with facts for policymakers, this much anticipated book's narrative-driven, accessible style will appeal to the general reader. This book is unique in that it analyzes the authoritative data on China's economy, foreign and domestic policy, and national security. * The expert judgments in this book paint a picture of a China confronting domestic challenges that are in many ways side effects of its economic successes, while simultaneously trying to take advantage of the foreign policy benefits of those same successes. China's Rise: Challenges and Opportunities from The China Balance Sheet Project, a joint, multiyear project of the Center for Strategic and International Studies and the Peterson Institute, discusses China's military modernization, China's increasing soft power influence in Asia and around the world, China's policy toward Taiwan, domestic political development, Beijing's political relations with China's provincial and municipal authorities, corruption and social unrest, rebalancing China's economic growth, the exchange rate controversy, energy and the environment, industrial policy, trade disputes, and investment issues.

The Shape of Dark Matter Haloes II. The Galactus HI Modelling & Fitting Tool

We present a new HI modelling tool called \textsc{Galactus}. The program has been designed to perform automated fits of disc-galaxy models to observations. It includes a treatment for the self-absorption of the gas. The software has been released into the public domain. We describe the design philosophy and inner workings of the program. After this, we model the face-on galaxy NGC2403, using both self-absorption and optically thin models, showing that self-absorption occurs even in face-on galaxies. It is shown that the maximum surface brightness plateaus seen in Paper I of this series are indeed signs of self-absorption. The apparent HI mass of an edge-on galaxy can be drastically lower compared to that same galaxy seen face-on. The Tully-Fisher relation is found to be relatively free from self-absorption issues.Comment: Accepted for publication by Monthly Notices RAS. Hi-res. version available at www.astro.rug.nl/~vdkruit/Petersetal-II.pd