Status of linear boundary-layer stability and the e to the nth method, with emphasis on swept-wing applications

The-state-of-the-art for the application of linear stability theory and the e to the nth power method for transition prediction and laminar flow control design are summarized, with analyses of previously published low disturbance, swept wing data presented. For any set of transition data with similar stream distrubance levels and spectra, the e to the nth power method for estimating the beginning of transition works reasonably well; however, the value of n can vary significantly, depending upon variations in disturbance field or receptivity. Where disturbance levels are high, the values of n are appreciably below the usual average value of 9 to 10 obtained for relatively low disturbance levels. It is recommended that the design of laminar flow control systems be based on conservative estimates of n and that, in considering the values of n obtained from different analytical approaches or investigations, the designer explore the various assumptions which entered into the analyses

Combined riblet and lebu drag reduction system

The invention is a system of flow control devices which result in reduced skin friction on aerodynamic and hydrodynamic surfaces. The devices cause a breakup of large-scale disturbances in the boundary layer of the flow field. The riblet device acts to reduce disturbances near the boundary layer wall by the use of longitudinal striations forming V-shaped grooves. These grooves are dimensional on the order of the wall vortices and turbulent burst dimensions. The large eddy breakup device is a small strip or airfoil which is suspended in the upper region of the boundary layer. Various physical mechanisms cause a disruption of the large-scale vortices. The combination of the devices of this invention result in a substantial reduction in skin friction drag

Effect of geometry variations on lee-surface vortex-induced heating for flat-bottom three-dimensional bodies at Mach 6

Studies have shown that vortices can produce relatively severe heating on the leeward surfaces of conceptual hypersonic vehicles and that surface geometry can strongly influence this vortex-induced heating. Results which show the effects of systematic geometry variations on the vortex-induced lee-surface heating on simple flat-bottom three-dimensional bodies at angles of attack of 20 deg and 40 deg are presented. The tests were conducted at a free-stream Mach number of 6 and at a Reynolds number of 1.71 x 10 to the 7th power per meter

Downstream influence of swept slot injection in hypersonic turbulent flow

Results of an experimental and numerical investigation of tangential swept slot injection into a thick turbulent boundary layer at Mach 6 are presented. Film cooling effectiveness, skin friction, and flow structure downstream of the swept slot injection were investigated. The data were compared with that for unswept slots, and it was found that cooling effectiveness and skin friction reductions are not significantly affected by sweeping the slot

THERMAL RADIATIVE HEAT TRANSFER TO SPACE FROM A BODY ENCLOSED BY A SEMITRANSPARENT BODY

Bumpers were proposed for protecting space radiator systems from penetration by meteoroids. The development of equations to determine the thermal energy dissipation to space by a hot body completely enclosed by a second body is presented. The particular case of heat dissipation from space radiators enclosed within the bumpers is considered, and the criteria for selection of bumper materials for a minimum weight radiator system are discussed. (auth

Predicted Effects of Tangential Slot Injection on Turbulent Boundary Layer Flow o?er a Wide Speed Range

Paper describes a numerical calculation method using eddy viscosity/mixing length-concepts for tangential slot injection (wall-wake

Improving the patient experience through patient portals: Insights from experienced portal users

Background: Patient portals have become part of the ecosystem of care as both patients and providers use them for a range of activities both individually and collaboratively. As patients and providers gain greater experience using portals, their use and needs related to portals may evolve. Objective: This study aimed to learn from experienced patient portal users to improve our understanding of their perspectives on portal use for collaboration and engagement as well as explore how using a portal influenced their experiences with primary care providers. Methods: Qualitative study involving 29 semi-structured interviews with family medicine patients from a large Academic Medical Center (AMC). Interviewees were patients with chronic conditions who had been identified by their providers as experienced portal users. Interview transcripts were analyzed using rigorous qualitative methods. Results: Common themes emerged around both logistical and psychological benefits of portal use. Logistical benefits included increased efficiency, improved ability to track their health information, and better documentation of communications and information during and between office visits. Psychological benefits were a greater sense of collaboration in care, increased trust in providers, and enhanced engagement in health care activities. Conclusion: Experienced portal users discussed ways in which patient portals improved both their ability to manage their care and their relationships with providers. Frequent users described a sense of collaboration with their providers and greater trust in the relationship. These findings suggest that portal use may be a mechanism through which patients can increase patient engagement and improve the patient experience

Assessing capacity to engage in healthcare to improve the patient experience through health information technology

Patient engagement is viewed as a means to improve patient care, increase population health, and decrease health care costs. Efforts to improve engagement are prevalent across healthcare, particularly through health information technology (HIT) tools such as patient portals. However, we know that not all patients have the same ability to engage, leading to potential disparities. We present the Engagement Capacity Framework and suggest that examining capacity for engagement would improve our ability to address currently unmeasured factors that facilitate engagement. The objective was to examine factors that influence an individual’s capacity for engagement through HIT. We administered a paper survey to patients seen for care in a Family Medicine Clinic at a large Academic Medical Center, measuring potential components of the Engagement Capacity Framework. 142 patients completed the survey. Respondents reported high self-efficacy, high resilience, and good or better quality of life. Most were willing to use the Internet. Almost 30% of respondents did not use a patient portal and 37% of these respondents were very or somewhat unwilling to use a portal. We observed significant positive correlations (p \u3e 0.05) between portal use and searching for health information online, using email and owning technology. For those who did not use a portal we asked about willingness to use a portal; portal willingness was positively correlated with willingness to use the Internet (p \u3c 0.01). Our findings emphasize the importance of assessing capacity for engagement in order to target interventions to those most in need, connecting them to necessary resources to allow more full participation in their care. Experience Framework This article is associated with the Innovation & Technology lens of The Beryl Institute Experience Framework. (http://bit.ly/ExperienceFramework) Access other PXJ articles related to this lens. Access other resources related to this len

A quality monitor and monitoring technique employing optically stimulated electron emission

A light source directs ultraviolet light onto a test surface and a detector detects a current of photoelectrons generated by the light. The detector includes a collector which is positively biased with respect to the test surface. Quality is indicated based on the photoelectron current. The collector is then negatively biased to replace charges removed by the measurement of a nonconducting substrate to permit subsequent measurements. Also, the intensity of the ultraviolet light at a particular wavelength is monitored and the voltage of the light source varied to maintain the light a constant desired intensity. The light source is also cooled via a gas circulation system. If the test surface is an insulator, the surface is bombarded with ultraviolet light in the presence of an electron field to remove the majority of negative charges from the surface. The test surface is then exposed to an ion field until it possesses no net charge. The technique described above is then performed to assess quality