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

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

Das Konzept des "controlled traffic farming" im ökologischen Gemüseanbau

Problems of machinery induced soil compaction are evident in organic vegetable production, resulting in stunted root growth and reduced yield. Controlled traffic farming (CTF) provides a possibility to restrict soil compaction to wheel tracks and create traffic-free vegetable beds with improved soil structure. A field experiment was established at a commercial organic vegetable farm in Denmark to investigate the effect of CTF on the growth of cabbage (Brassica oleracea), potato (Solanum tuberosum) and beetroot (Beta vulgaris). Random traffic farming (RTF) served as the control. Preliminary results show that root intensity was higher in the CTF treatment compared to the RTF treatment for cabbage at the end of the growing season, indicating a better soil structure in this system. Crop yields were 23 to 70% higher in all three investigated crops in the CTF treatments. These results point towards the potential to increase the use of the CTF system in organic vegetable production

Controlled traffic farming increases root growth, crop and soil nitrogen in vegetable cropping systems

Results from field trials on sandy and sandy loam of controlled traffic farmin

Controlled traffic farming increased crop yield, root growth, and nitrogen supply at two organic vegetable farms

Increased farm machinery weight in agricultural production results in soil compaction. Controlled traffic farming (CTF) restricts traffic to permanent lanes, thereby creating traffic free beds for crop production. Field experiments were conducted at two organic vegetable farms in Denmark, on a sandy loam (2013–2016) and on coarse sand (2013–2015) to investigate CTF effects compared with random traffic farming (RTF) on vegetable yield, root growth, and soil mineral nitrogen (N). Root growth was measured using minirhizotrons. White cabbage, potato, and beetroot yield increased by 27%, 70% and 42%, respectively, in CTF compared with RTF in 2015 and winter squash indicated a yield increase of 43% on sandy loam in 2016. White cabbage (2015) and potato, beetroot and winter squash (2016) grew 2–25 times more roots and beetroot grew deeper roots under CTF compared with RTF on sandy loam in 2016. On coarse sandy soil, beetroot root frequency was 1.4 times greater under CTF than under RTF and beetroot roots grew deeper than 1.5 m under both treatments in 2015. Soil mineral N and potential net N mineralization were equal between treatments or higher in CTF by 2–41 kg ha−1 and 11 mg kg−1 35 days−1, respectively, indicating N supply was maintained or increased in this system. Despite the variability in crop and root growth responses to traffic between years and crops, the effects were always equal or positive for CTF following treatment implementation. Therefore, our results encourage the use of CTF for organic vegetable production under temperate conditions

Development of a 611 MHz feed for a 9-meter reflector

A 2 by 2 array of fan dipoles was designed as a feed for an existing 9.14 meter diameter reflector. Baffles (conducting fences) were utilized to reduce mutual coupling between dipoles and to improve the feed radiation pattern in the H plane. Significant strut scattering effects are noted in the secondary patterns of the reflector antenna

Effect of Compliant Wall Motion on Turbulent Boundary Layers

A critical analysis of available compliant wall data which indicated drag reduction under turbulent boundary layers is presented. Detailed structural dynamic calculations suggest that the surfaces responded in a resonant, rather than a compliant, manner. Alternate explanations are given for drag reductions observed in two classes of experiments: (1) flexible pipe flows and (2) water-backed membranes in air. Analysis indicates that the wall motion for the remaining data is typified by short wavelengths in agreement with the requirements of a possible compliant wall drag reduction mechanism recently suggested by Langley. Copyright © 1977 American Institute of Physics

Any general conclusions to draw on deep roots from the complex effects of cropping systems?

Overview of deep roots in vegetable cropping system

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