Curved centerline air intake for a gas turbine engine

An inlet for a gas turbine engine was disposed about a curved centerline for the purpose of accepting intake air that is flowing at an angle to engine centerline and progressively turning that intake airflow along a curved path into alignment with the engine. This curved inlet is intended for use in under the wing locations and similar regions where airflow direction is altered by aerodynamic characteristics of the airplane. By curving the inlet, aerodynamic loss and acoustic generation and emission are decreased

Effect of Meditation Before Eccentric Exercise on Induced Delayed Onset Muscle Soreness in Elbow Flexors of Normal Healthy Adults

Delayed onset muscle soreness (DOMS) is a condition characterized by discomfort and swelling in the muscle that typically occurs after high-intensity or eccentric exercise. The positive psychological and physiological effects of mindfulness meditation suggest that it may be useful as a method for preventing DOMS. PURPOSE: To examine the effect of mindfulness meditation on DOMS in normal, healthy adults. METHODS: Twenty-two undergraduate students, ages 18-22, participated in an eccentric bicep curl exercise protocol and 15-minute mindfulness meditation session. Participants exercised one arm before the meditation session (control arm), and one arm after the meditation session (experimental arm). Range of motion (ROM) measurements were taken using a plastic goniometer and pain-pressure threshold (PPT) measurements were taken using a force sensor directly before exercise and approximately 48 hours after exercise. A two-tailed paired t-test determined if there was a significant difference in the change in measurement from pre-testing to post-testing between the control and experimental arm. RESULTS: The mean (sd) pre- and post-test ROM values in degrees were 144.32 (4.47) and 138.32 (10.69) for the control arm and 143.91 (4.67) and 141.91(4.97) for the experimental arm. The ROM post-test values were 4.2% lower than the pre-test values for the control arm and 1.4% lower than the pre-test values for the experimental arm. There was no significant difference in the change in ROM between the control arm and the experimental arm (t(22)= -1.97, p = 0.063). The mean (sd) pre- and post-test PPT values in newtons were 15.92 (6.50) and 12.29 (5.62) for the control arm and 15.74 (5.43) and 12.53 (5.27) for the experimental arm. The PPT post-test values were 22.9% lower than the pre-test values for the control arm and 20.4% lower than the pre-test values for the experimental arm There was no significant difference in the change in PPT between the control arm and the experimental arm (t(22)= -0.54, p = 0.593). CONCLUSION: The present study demonstrates that mindfulness meditation did not have a significant effect on DOMS, suggesting that mindfulness meditation would not be an effective method for preventing DOMS

Environmental variables controlling soil respiration on diurnal, seasonal and annual time-scales in a mixed mountain forest in Switzerland

Studies on soil respiration in mountain forests are rather scarce compared to their broad distribution. Therefore, we investigated daily, seasonal and annual soil respiration rates in a mixed forest (Lägeren), located at about 700m in the Swiss Jura mountains, during 2years (2006 and 2007). Soil respiration (SR) was measured continuously with high temporal resolution (half-hourly) at one single point (SRautomated) and periodically with high spatial resolution (SRmanual) at 16 plots within the study site. Both, SRautomated and SRmanual showed a similar seasonal cycle. SR strongly depended on soil temperature in 2007 (R 2=0.82-0.92), but less so in 2006 (R 2=0.56-0.76) when SR was water limited during a summer drought. Including soil moisture improved the fit of the 2006 model significantly (R 2=0.78-0.97). Total annual SR for the study site was estimated as 869g C m−2year−1 for 2006 and as 907g C m−2year−1 for 2007 (uncertainty <10% at the 95% confidence interval, determined by bootstrapping). Selected environmental conditions were assessed in more detail: (1) Rapid, but contrasting changes of SR were found after summer rainfall. Depending on soil moisture at pre-rain conditions, summer rain could either cause a pulse of CO2 from the soil or an abrupt decrease of SRautomated due to water logging of soil pores. (2) Two contrasting winter seasons resulted in SR being about 60-70% (31.2-44.6g C m−2) higher during a mild winter (2007) compared to a harsh winter (2006). (3) Analysing SR for selected periods on a diurnal scale revealed a counter-clockwise hysteresis with soil surface temperatures. This indication of a time-lagged response of SR to temperature was further supported by a very strong relationship (R 2=0.86-0.90) of SR to soil temperature with a time-lag of 2-4

Effects of heat and drought on carbon and water dynamics in a regenerating semi-arid pine forest: a combined experimental and modeling approach

Predicting the net effects on the carbon and water balance of semi-arid forests under future conditions depends on ecosystem processes responding to changes in soil and atmospheric drought. Here we apply a combination of field observations and soil-plant-atmosphere modeling (SPA) to study carbon and water dynamics in a regenerating ponderosa pine forest. The effects of soil and atmospheric drought were quantified based on a field irrigation experiment combined with model simulations. To assess future effects of intensifying drought on ecosystem processes, the SPA model was run using temperature and precipitation scenarios for 2040 and 2080. Experimentally increased summer water availability clearly affected tree hydraulics and enhanced C uptake in both the observations and the model. Simulation results showed that irrigation was sufficient to eliminate soil water limitation and maintaining transpiration rates, but gross primary productivity (GPP) continued to decrease. Observations of stomatal conductance indicated a dominant role of vapor pressure deficit (VPD) in limiting C uptake. This was confirmed by running the simulation under reduced atmospheric drought (VPD of 1 kPa), which largely maintained GPP rates at pre-drought conditions. The importance of VPD as a dominant driver was underlined by simulations of extreme summer conditions. We found GPP to be affected more by summer temperatures and VPD as predicted for 2080 (-17%) than by reductions in summer precipitation (-9%). Because heterotrophic respiration responded less to heat (-1%) than to reductions in precipitation (-10%), net ecosystem C uptake declined strongest under hotter (-38%) compared to drier summer conditions (-8%). Considering warming trends across all seasons (September-May: +3 °C and June-August: +4.5 °C), the negative drought effects were largely compensated by an earlier initiation of favorable growing conditions and bud break, enhancing early season GPP and needle biomass. An adverse effect, triggered by changes in early season allocation patterns, was the decline of wood and root biomass. This imbalance may increase water stress over the long term to a threshold at which ponderosa pine may not survive, and highlights the need for an integrated process understanding of the combined effects of trends and extremes

Interdisciplinary Team Teaching: Lessons for Engineering Instructors from a Capstone Course in Environmental Studies

The capstone course teaches students to analyze global environmental issues, resources, and human activities with a systems approach based on scientific, economic, political, social and ethical perspectives. Such an intrinsically multifaceted subject demands interdisciplinary treatment. To deliver the interdisciplinary treatment, the course uses diverse faculty teams comprised of faculty from fields in the natural and social sciences, engineering, and business. This work describes the interdisciplinary team teaching strategies adopted for the course and how they evolved with subsequent offerings of the course. We present assessment data measuring how well students achieve course objectives. Finally, experience gleaned from this course for non-majors has produced ideas for lessons engineering instructors can apply to their own courses

Dying by drying: Timing of physiological stress thresholds related to tree death is not significantly altered by highly elevated CO2_{2}

Drought‐induced tree mortality is expected to occur more frequently under predicted climate change. However, the extent of a possibly mitigating effect of simultaneously rising atmospheric [CO$_{2}$] on stress thresholds leading to tree death is not fully understood, yet. Here, we studied the drought response, the time until critical stress thresholds were reached and mortality occurrence of Pinus halepensis (Miller). In order to observe a large potential benefit from eCO$_{2}$, the seedlings were grown with ample of water and nutrient supply under either highly elevated [CO$_{2}$] (eCO$_{2}$, c. 936 ppm) or ambient (aCO$_{2}$, c. 407 ppm) during 2 years. The subsequent exposure to a fast or a slow lethal drought was monitored using whole‐tree gas exchange chambers, measured leaf water potential and non‐structural carbohydrates. Using logistic regressions to derive probabilities for physiological parameters to reach critical drought stress thresholds, indicated a longer period for halving needle starch storage under eCO$_{2}$ than aCO$_{2}$. Stomatal closure, turgor loss, the duration until the daily tree C balance turned negative, leaf water potential at thresholds and time‐of‐death were unaffected by eCO$_{2}$. Overall, our study provides for the first‐time insights into the chronological interplay of physiological drought thresholds under long‐term acclimation to elevated [CO$_{2}$]