I use a game theoretic model of diversionary war incentives to help explain the lack of a consistent empirical relationship between domestic conditions and the use of force abroad. I argue that when diversionary behavior is about demonstrating competence rather than creating a short-term ‘‘rally round the flag’’ effect, a leader has incentives to use force against a challenging target, and this...

This paper describes a dynamic system-a system that develops order only when dissipating energy-comprising millimeter to centimeter scale gears that self-assemble into a simple machine at a fluid/air interface. The gears are driven externally and indirectly by magnetic interactions; they are made of poly(dimethylsiloxane) (PDMS) or magnetically doped PDMS, and fabricated by soft lithography. Tr...

In this paper, the forming principle, meshing features and tooth surface equation were introduced. And the modal parameters distribution of cylindrical gears with arcuate tooth trace was researched. The results show: 1. The modulus was the biggest impact factor for modal and natural frequency of cylindrical gears with arcuate tooth trace, then tooth width, and the radius of tooth line have the ...

The importance of plastic gears for modern industry is growing every year. The engineer sizing plastic gears has a very difficult task. There is no international standard available for the strength analysis. The only method publicly accepted is the German guideline VDI2545. In addition to a lack of calculation methods there is a need for measuring material properties. This paper shall give an o...

The tooth flanks of bevel gears with involute teeth are still cut using approximations such as Tredgold’s and octoid curves, while the geometry of the exact spherical involute is well known. The modeling of the tooth flanks of gears with skew axes, however, still represents a challenge to geometers. Hence, there is a need to develop algorithms for the geometric modeling of these gears. As a mat...

The recently available capability for the free-form milling of gears of various gear types and sizes — all within one manufacturing system — is becoming increasingly recognized as a flexible machining process for gears. This paper addresses the manufacturing and quality of gears made by free-form milling, with an added focus on the specific process properties of the parts. Finally, the potentia...

Centrifugal compressor and turbine manufacturers are building machines that operate at increasingly higher speeds to reduce the size and cost of their equipment. Helical gears are commonly used to step down the speed of these machines to match nominal motor and generator speeds. The demand for higher compressor and turbine speeds has resulted in an increase in the maximum pitch line velocities ...

There were severe pitting corrosions on the surface of transmission gears in diesels. The cause of metal fatigue pitting of gear surface is analyzed in the paper, which based on the contact fatigue experiment of 18Cr2Ni4WA carburizing and quenching gears used in the diesel engine. Causes of pitting on harden tooth surface are studied from three aspects: gear surface residual stress field, oil f...

This paper extends the multi-body dynamics modelling strategy for rigid gears to include compliant gear bodies in multi-mesh transmissions. Only external, fixed center, helical or spur gears are considered. This formulation combines distributed gear mesh stiffness and gear blank compliance models in a multi-body dynamics framework resulting in a set of non-linear differential equations with tim...

by Jason L. Taylor Editor’s Note: This edition features current research, practice, and policy related to the Joyce Foundation’s Shifting Gears initiative beginning with an interview with Whitney Smith, Manager of the Employment Program at the Joyce Foundation. Julie Strawn, Center for Law and Social Policy, presents a national perspective of basic skills reform efforts similar to Shifting Gear...