Control of jet noise continues to be an important research topic. Exhaust-nozzle chevrons have been shown to reduce jet noise, but parametric effects are not well understood. Additionally, thrust loss due to chevrons at cruise suggests significant benefit from active chevrons. The focus of this study is development of an active chevron concept for the primary purpose of parametric studies for j...

condylar dislocation is not an uncommon condition and occurs when the condyles are displaced anterior to the articular eminence and are unable to reduce back into the glenoid fossa. long-standing dislocations are difficult to treat with the conservative methods and usually need surgical intervention. in this paper, a long-standing dislocation treated by bilateral extra-oral ramus osteotomy is d...

This paper presents the modified design of a bidirectional electrothermal chevron beam microtweezer proposed by J. K. Luo [1]. The original design has been modified to include inward in-plane motion. Thus, the modified design is capable of bidirectional motion. The structures are designed and simulated using COMSOL Multiphysics 4.2a. The bidirectional chevron beam microtweezer shows an in-plane...

We study the de Gennes free energy for smectic A liquid crystals over S2-valued vector fields to understand the chevron (zigzag) pattern formed in the presence of an applied magnetic field. We identify a small dimensionless parameter ε, and investigate the behaviors of the minimizers when the field strength is of order O(ε−1). In this regime, we show via Γ-convergence that a chevron structure w...

We examined the apparent dissociation of perceived length and perceived position with respect to the Müller-Lyer (M-L) illusion. With the traditional (two-chevron) figure, participants made accurate open-loop pointing responses at the endpoints of the shaft, despite the presence of a strong length illusion. This apparently non-Euclidean outcome replicated that of Mack, Heuer, Villardi, and Cham...

o bjectives: the aim of this study was to investigate the displacement and stress distri- bution during surgically assisted rapid maxillary expansion under different surgical conditions with tooth- and bone-borne devices. materials and methods: three-dimensional (3d) finite element model of a maxilla was constructed and an expansion force of 100 n was applied to the left and right molars and pr...

This study presents the status and results from an effort to design, fabricate, and test an adaptive jet engine chevron concept based upon embedding shape memory alloy (SMA) actuators in a composite laminate, termed a SMA hybrid composite (SMAHC). The approach for fabricating the adaptive SMAHC chevrons involves embedding prestrained Nitinol actuators on one side of the mid-plane of the composi...

Chevron mixing devices are used to reduce noise from commercial separate-flow turbofan engines. Mechanical chevron serrations at the nozzle trailing edge generate axial vorticity that enhances jet plume mixing and consequently reduces far-field noise. “Fluidic chevrons” generated with air injected near the nozzle trailing edge create a vorticity field similar to that of the mechanical chevrons ...