Hypersonic Boundary Layer Turbulence

Kevin WanklynHypersonic flow involves an extremely complex flow system. The parameters that affect laminar to turbulent flow, especially at hypersonic speeds, play a large role in developing accurate predictions of drag and heating. Transition from laminar to turbulent flow involves a multifaceted scheme consisting of a variety of mechanisms. The study of these conditions has yielded a reliable understanding of their role pertaining to planar bodies or axisymmetric shapes. The Boundary Layer Transition (BOLT1) flight experiment was developed to stimulate the advancement of transition predictions and assess experimental capabilities by introducing a more geometrically complex surface. The new geometry includes a concave surface; however, its most prominent features are the leading edges. BOLT is a collaborative effort spanning multiple organizations whose purpose is to establish new flow predictions and collect experimental data for the complex surface. This project includes the Air Force Office of Scientific Research (AFOSR), Air Force Research Lab (AFRL), Purdue University, Texas A&M University (TAMU), University of Minnesota, John Hopkins University Applied Physics Laboratory (JUAPL), and NASA-Langley. Hypersonic flow measurements for BOLT1 were taken by utilizing the advanced wind tunnel facilities housed at TAMU, NASA, and Purdue. Each facility tested the scale model and data was collected and compared to the computational fluid dynamics (CFD) analysis and predictions performed by Minnesota and TAMU. The new studies conducted are on Boundary Layer Turbulence (BOLT2). BOLT2 is an extended geometry of BOLT1 and focuses more on the effects of turbulent flow on the model. BOLT2 IR thermography was conducted in TAMU's Mach 6 Quiet Tunnel (M6QT) and the Actively Controlled Expansion (ACE) hypersonic tunnel. Measurements and CFD conducted on BOLT2 will yield a better understanding of the turbulent flow and boundary layer transition

Potential methodological influences on the determination of particle retention efficiency by suspension feeders: Mytilus edulis and Ciona intestinalis

The retention efficiency (RE) of suspension-feeding bivalve molluscs depends on particle size and is generally assumed to decline below a maximum retention of particles larger than 3 to 7 µm. Previous suggestions that the RE spectrum of mussels Mytilus edulis can exhibit variability, possibly as a result of physiological regulation, have been attributed to artifacts associated with the indirect method. The possibility that variable physical properties of seston particles and/or miscalculations can result in inaccurate RE measurements was examined using 3 methodologies (static, flow-through and a new approach based on the static method) and 3 particle sources (natural seston, algal cell monocultures and clay). Measurements obtained with the static method varied depending on the selected sampling interval. However, this artifact can be removed using frequent sampling and a regression analysis approach. Accurate RE measurements can be obtained with the flow-through method when feeding behaviour is flow independent. For all particle suspensions and methods, mussels from the study site in Lysefjord, Norway, had a maximum RE for particles >8–11 µm (1 to 5 September 2015). The RE for smaller particles declined gradually, with 50–60% retention of 4 µm particles and 30–40% retention of 2 µm particles. Differences in the RE size spectra of mussels and tunicates Ciona intestinalis, collected and measured at the same site, further indicated that RE was not influenced by potentially confounding methodological factors. Assumptions regarding the RE spectrum of bivalves have contributed to many conclusions on their ecosystem interactions. The reliability of clearance rate measurements obtained using the indirect method can only be assured if the effective retention of tracer particles is confirmed and not assumed.publishedVersio

"Je suis moy-mesmes la matiere de mon livre": Sexual Ambiguities and Friendship in Montaigne's Essais

While ambiguity's ultimate role is to create "infinis Essais" in the minds of Montaigne's readers, gender, sexuality and friendship play decisive roles in the significance of this ambiguity. Montaigne's oscillation between misogyny and feminism is manifested in the female voice and female persona that the essayist establishes for himself. His exploration of friendship with men and women offers the reader a plethora of contradictions, problematizations, destabilization and uncertainty; "De l'amitié" is at the same time an hommage to and mourning for Etienne de La Boétie. Montaigne makes his readers consider love between men in ways they most certainly had not before. He recreates the ancients' debate about love between men, thus continuing their contemplation of homosexuality to an infinity that is atemporal. Montaigne's friendship with Marie de Gournay enables her to multiply the meaning of his Essais with a feminist objective, thereby problematizing the misogynistic passages in Montaigne's Essais

Comparison of the Standardized Video Interview and Interview Assessments of Professionalism and Interpersonal Communication Skills in Emergency Medicine

ObjectivesThe Association of American Medical Colleges Standardized Video Interview (SVI) was recently added as a component of emergency medicine (EM) residency applications to provide additional information about interpersonal communication skills (ICS) and knowledge of professionalism (PROF) behaviors. Our objective was to ascertain the correlation between the SVI and residency interviewer assessments of PROF and ICS. Secondary objectives included examination of 1) inter‐ and intrainstitutional assessments of ICS and PROF, 2) correlation of SVI scores with rank order list (ROL) positions, and 3) the potential influence of gender on interview day assessments.MethodsWe conducted an observational study using prospectively collected data from seven EM residency programs during 2017 and 2018 using a standardized instrument. Correlations between interview day PROF/ICS scores and the SVI were tested. A one‐way analysis of variance was used to analyze the association of SVI and ROL position. Gender differences were assessed with independent‐groups t‐tests.ResultsA total of 1,264 interview‐day encounters from 773 unique applicants resulted in 4,854 interviews conducted by 151 interviewers. Both PROF and ICS demonstrated a small positive correlation with the SVI score (r = 0.16 and r = 0.17, respectively). ROL position was associated with SVI score (p < 0.001), with mean SVI scores for top‐, middle‐, and bottom‐third applicants being 20.9, 20.5, and 19.8, respectively. No group differences with gender were identified on assessments of PROF or ICS.ConclusionsInterview assessments of PROF and ICS have a small, positive correlation with SVI scores. These residency selection tools may be measuring related, but not redundant, applicant characteristics. We did not identify gender differences in interview assessments.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/150548/1/aet210346_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/150548/2/aet210346.pd

An Integrated Ecosystem Approach for Assessing the Potential Role of Cultivated Bivalve Shells as Part of the Carbon Trading System

The role of bivalve mariculture in the CO2 cycle has been commonly evaluated as the balance between respiration, shell calcium carbonate sequestration and CO2 release during biogenic calcification. However, this approach neglects the ecosystem implications of cultivating bivalves at high densities, e.g. the impact on phytoplankton dynamics and benthic-pelagic coupling, which can significantly contribute to the CO2 cycle. Therefore, an ecosystem approach that accounts for the trophic interactions of bivalve aquaculture, including dissolved and particulate organic and inorganic carbon cycling, is needed to provide a rigorous assessment of the role of bivalve mariculture in the CO2 cycle. On the other hand, the discussion about the inclusion of shells of cultured bivalves into the carbon trading system should be framed within the context of ecosystem goods and services. Humans culture bivalves with the aim of producing food, not sequestering CO2 in their shells, therefore the main ecosystem good provided by bivalve aquaculture is meat production, and shells should be considered as by-products of this human activity. This reasoning provides justification for dividing up respired CO2 between meat and shell when constructing a specific bivalve CO2 budget for potential use of bivalve shells in the carbon trading system. Thus, an integrated ecosystem approach, as well as an understanding of the ecosystems goods and services of bivalve aquaculture, are 2 essential requisites for providing a reliable assessment of the role of bivalve shells in the CO2 cycle

Simulating the effect of high-intensity sound on cetaceans: Modeling approach and a case study for Cuvier’s beaked whale ( Ziphius cavirostris

A finite element model is formulated to study the steady-state vibration response of the anatomy of a whale (Cetacea) submerged in seawater. The anatomy was reconstructed from a combination of two-dimensional (2D) computed tomography (CT) scan images, identification of Hounsfield units with tissue types, and mapping of mechanical properties. A partial differential equation model describes the motion of the tissues within a Lagrangean framework. The computational model was applied to the study of the response of the tissues within the head of a neonate Cuvier's beaked whale Ziphius cavirostris. The characteristics of the sound stimulus was a continuous wave excitation at 3500 Hz and 180 dB re: 1 mu Pa received level, incident as a plane wave. We model the beaked whale tissues embedded within a volume of seawater. To account for the finite dimensions of the computational volume, we increased the damping for viscous shear stresses within the water volume, in an attempt to reduce the contribution of waves reflected from the boundaries of the computational box. The mechanical response of the tissues was simulated including: strain amplitude; dissipated power; and pressure. The tissues are not likely to suffer direct mechanical or thermal damage, within the range of parameters tested. (c) 2006 Acoustical Society of America

MMN and Differential Waveform

A mismatch negativity response (MMN) and a new differential waveform were derived in an effort to evaluate a neural refractory or recovery effect in adult listeners. The MMN was elicited using oddball test runs in which the standard and deviant stimuli differed in frequency. To derive the differential waveform, the same standard and deviant stimuli were presented alone. MMN responses were obtained by subtracting the averaged responses to standards from the deviants. The differential waveforms were obtained by subtracting the averaged responses to standards presented alone from deviants presented alone. Scalp topography for the MMN and differential waveforms were similar. A significant (p < .05) positive and negative correlation was found between the earlier and later components of the bimodal MMN and the N1 and P2 component of the differential waveform, respectively. Further, N1 and P2 of the differential waveform were significant (p < .05) predictor variables of early and late peak amplitudes of the MMN. These results suggest that refractory effects may overlay/modify the morphology of the MMN waveform

Ecosystem models of bivalve aquaculture: Implications for supporting goods and services

In this paper we focus on the role of ecosystem models in improving our understanding of the complex relationships between bivalve farming and the dynamics of lower trophic levels. To this aim, we review spatially explicit models of phytoplankton impacted by bivalve grazing and discuss the results of three case studies concerning an estuary (Baie des Veys, France), a bay, (Tracadie Bay, Prince Edward Island, Canada) and an open coastal area (Adriatic Sea, Emilia-Romagna coastal area, Italy). These models are intended to provide insight for aquaculture management, but their results also shed light on the spatial distribution of phytoplankton and environmental forcings of primary production. Even though new remote sensing technologies and remotely operated in situ sensors are likely to provide relevant data for assessing some the impacts of bivalve farming at an ecosystem scale, the results here summarized indicate that ecosystem modelling will remain the main tool for assessing ecological carrying capacity and providing management scenarios in the context of global drivers, such as climate change

Cave spiders choose optimal environmental factors with respect to the generated entropy when laying their cocoon

The choice of a suitable area to spiders where to lay eggs is promoted in terms of Darwinian fitness. Despite its importance, the underlying factors behind this key decision are generally poorly understood. Here, we designed a multidisciplinary study based both on in-field data and laboratory experiments focusing on the European cave spider Meta menardi (Araneae, Tetragnathidae) and aiming at understanding the selective forces driving the female in the choice of the depositional area. Our in-field data analysis demonstrated a major role of air velocity and distance from the cave entrance within a particular cave in driving the female choice. This has been interpreted using a model based on the Entropy Generation Minimization - EGM - method, without invoking best fit parameters and thanks to independent lab experiments, thus demonstrating that the female chooses the depositional area according to minimal level of thermo-fluid-dynamic irreversibility. This methodology may pave the way to a novel approach in understanding evolutionary strategies for other living organisms