Research on the underlying structure of psychopathology has found that a single general psychopathology factor may underlie all mental disorders. This finding is consistent with decades of research showing that the same risk factors are associated with many different disorders. We review these findings and discuss a primary implication: that clinicians could potentially use the same treatment for individuals with different and comorbid mental disorders. Such a transdiagnostic approach is not a new concept, but these treatments are receiving renewed interest. Recently developed transdiagnostic treatments have been shown to be effective in research settings, but these treatments do not meet several community mental health needs. Consequently, we provide an evidence-based rationale for a continuous-enrollment, fully transdiagnostic cognitive-behavioral group treatment that is informed by research on the structure of psychopathology. We conclude with suggestions for future research that integrate basic science research, treatment research, and clinical practice.

This paper presents rotordynamic data obtained within a test facility studying the aerodynamics of a high-speed centrifugal compressor for aero-engine applications. The experimental overhung compressor is supported by two rolling element bearings. The compressor-end ball bearing is supported by an oil-fed squeeze film damper. After some period of operation, the compressor began to exhibit a unique nonlinear increase in the rotordynamic response followed by an unexpected subsynchronous whirl instability as the speed continued to increase. Finally, as the rotor speed was increased further, the rotor re-stabilized. A numerical model of the compressor system was created using a commercially available software suite. This model indicates the effective weight of the damper support has a significant effect on the frequency of the second critical speed. Increasing this weight causes the second critical speed, originally predicted at 35,200 RPM, to shift down to 15,650 RPM. This increase in the support weight is due to inertial interaction between the damper support and the surrounding static structure. The increased shaft deflection that occurs as the rotor passes through this shifted critical speed causes the damper to lockup, resulting in the increased response observed experimentally. At a slightly higher speed, Alford-type aerodynamic cross-coupling forces excite the two subsynchronous critical speeds. Finally, as the rotor departs from the second critical speed, the damper unlocks and is able to effectively suppress the Alford-type instabilities, allowing the rotor to return to stable operation.

Computational tools have become increasingly important in design and research applications in recent years due to increasing computational resources. In most cases, model geometry and flow-physics are simplified to reduce the complexity of the computational model. While this was necessary historically, modern computational tools are capable of including realistic features such as fillets, surface roughness, and heat transfer. This work presents extensive and systematic numerical results from a simulation of a centrifugal compressor stage for an aero-engine application. Numerical results are compared to detailed experimental data to investigate the effect of various modelling decisions, including turbulence models, on the predicted aerodynamics developing through the diffuser passage. Roughness and the inclusion of fillets significantly impact the flow development, especially with the SST turbulence model. This approach leads to the conclusion that the BSL-EARSM model is best able to predict the experimentally determined diffuser flow profiles and overall performance trends with the inclusion of the previously mentioned model features. Additionally, the misleading conclusions can be reached if modelling decisions are based on merely matching overall performance values. Finally, frozen rotor simulations are used to roughly approximate the impact of unsteadiness on the flow field. The results show a significant impact and also that the inclusion of approximate unsteady effects tends to further improve the predictive capability of the computational models that were considered.

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An additive manufactured (AM) vaned diffuser for use in a centrifugal compressor research facility was designed and implemented. Utilizing an AM process to manufacture the diffuser reduces the long lead time that is associated with conventionally manufactured diffusers, and it increases the instrumentation capabilities within the flow path. Several AM techniques and a variety of plastic and metal materials were evaluated for this application. A high-temperature, stereolithography (SL) resin was chosen because of the tight dimensional tolerances maintained by the SL process. Utilizing a high-temperature plastic also results in manufacturing costs that are significantly less than using a metal material. Samples of the chosen material were subjected to mechanical testing to investigate the effects of build direction (BD) and to verify its properties in the high-temperature compressor environment. To fit within the manufacturing space of an SL machine, the AM diffuser consists of seven radially symmetric sections that are assembled to form a complete flow path. Considerations for modifying the research facility to allow for this unique installation are presented. Precision measurements of the AM components were obtained to compare printed and modeled geometry, and they demonstrate close alignment of flow path dimensions.