Critical Assessment of Hybrid RANS-LES Modeling for Attached and Separated Flows

The objective of this study is to evaluate a recently proposed dynamic hybrid Reynolds-averaged Navier-Stokes (RANS)-Large Eddy Simulation (LES) modeling framework that seeks to effectively address issues regarding RANS-to-LES transition and explicit grid dependence inherent in most current hybrid RANS-LES (HRL) models. RANS-to-LES transition in the investigated dynamic HRL (DHRL) model is based on the physical concept of maintaining continuity of total turbulence production using two rigorously separated turbulent stress parameters, where one is obtained from the RANS model and the other from the LES model. Computations of two canonical test cases—two-dimensional turbulent channel flow and backward facing step flow—were performed to assess the potential of the DHRL model for predicting both attached and separated turbulent flows. This investigation attempts to evaluate the ability of the DHRL method to reproduce the detailed physics of attached and separated turbulent flows, as well as to resolve the issues concerning log-layer mismatch and delayed break down of separated shear layers. The DHRL model simulation results are compared with experimental and DNS data, along with the computational results for other HRL and RANS models. In summary, these comparisons demonstrate that the DHRL framework does address many of the weaknesses inherent in most current HRL models

Economic Impacts of the Ethanol Industry in Nebraska

The U.S. Department of Energy data on Nebraska’s ethanol production started in 1985 at 9 million gallons per year. Ten years later in 1995 it was 200 million gallons as shown below. A little over ten years later starting in 2007, the big jump in production was 858 million gallons, and five years later by 2011 it was 2,062 million. The twenty year growth from 1995 to 2014 was approximately tenfold. Since 2007 the effects on Nebraska’s economy and rural areas have been both sustained and substantial. The purpose of this economic study is to estimate for a five year period the value of production and compare that value to major commodity production values in Nebraska. In addition, the study will measure productive capacity, employment, net returns, in-state utilization and out-of- state shipments. The economic impacts are composed of direct and indirect effects associated with output, employment, labor and indirect business taxes

The Relationship Between Tolerance For Ambiguity And Students Propensity To Cheat On A College Exam

Businesses in the United States are being ravaged internally for a total of up to $400 billion yearly by white-collar crime (Martin, 1998).   Fraud, the culprit, is defined as, “deceit; trickery; cheating” (Webster’s New World dictionary, 1978).  This phenomenon knows no bounds, has no feelings, respects no one; and its perpetrators are described as the “greatest threat to businesses of all sizes” by Mark Simmons, a New York-based auditor with 20 years’ experience of fighting fraud (Applegate, 1998).  This exploratory study is aimed at gaining a greater understanding of the psychological consistency of these perpetrators, who remain a constant threat to business education

Lower pollen nutritional quality delays nest building and egg laying in Bombus terrestris audax micro-colonies leading to reduced biomass gain

This version of the article has been accepted for publication, after peer review (when applicable) and is subject to Springer Nature’s AM terms of use, but is not the Version of Record and does not reflect post-acceptance improvements, or any corrections. The Version of Record is available online at: http://dx.doi.org/10.1007/s13592-021-00885-3The performance of Bombus terrestris micro-colonies fed five diets differing in pollen species composition and level of nine essential amino acids (EAA; leucine, lysine, valine, arginine, isoleucine, phenylalanine, threonine, histidine, methionine) was assessed for 37 days by recording total biomass gain, nest building initiation, brood production (eggs, small and large larvae, pupae, drones), nectar, and pollen collection. Stronger colony performance was linked to higher amino acid levels but no consistent differences in biomass gain were recorded between mono- and poly-species diets. Poorest performance occurred in micro-colonies offered pure oilseed rape (OSR) pollen which contained the lowest EAA levels. Reduced micro-colony development (delayed nest initiation and lower brood production) was related to OSR proportion in the diet and lower EAA levels. Results are discussed in relation to selection of plant species in the design of habitats to promote bee populations

A sham-controlled study of neurofeedback for pain management

Background: Neurofeedback (NFB) attempts to alter the brain’s electrophysiological activity and has shown potential as a pain management technique. Existing studies, however, often lack appropriate control groups or fail to assess whether electrophysiological activity has been successfully regulated. The current study is a randomized controlled trial comparing changes in brain activity and pain during NFB with those of a sham-control group. Methods: An experimental pain paradigm in healthy participants was used to provide optimal control of pain sensation. Twenty four healthy participants were blind randomized to receive either 10 × NFB (with real EEG feedback) or 10 × sham (with false EEG feedback) sessions during noxious cold stimulation. Prior to actual NFB training, training protocols were individually determined for each participant based on a comparison of an initial 32-channel qEEG assessment administered at both baseline and during an experimental pain task. Each individual protocol was based on the electrode site and frequency band that showed the greatest change in amplitude during pain, with alpha or theta up-regulation at various electrode sites (especially Pz) the most common protocols chosen. During the NFB sessions themselves, pain was assessed at multiple times during each session on a 0–10 rating scale, and ANOVA was used to examine changes in pain ratings and EEG amplitude both across and during sessions for both NFB and sham groups. Results: For pain, ANOVA trend analysis found a significant general linear decrease in pain across the 10 sessions (p = 0.015). However, no significant main or interaction effects of group were observed suggesting decreases in pain occurred independently of NFB. For EEG, there was a significant During Session X Group interaction (p = 0.004), which indicated that EEG amplitude at the training site was significantly closer to the target amplitude for the NFB compared to the sham group during painful stimulation, but this was only the case at the beginning of the cold task. Conclusion: While these results must be interpreted within the context of an experimental pain model, they underline the importance of including an appropriate comparison group to avoid attributing naturally occurring changes to therapeutic effects

Lower pollen nutritional quality delays nest building and egg laying in Bombus terrestris audax micro-colonies leading to reduced biomass gain

The performance of Bombus terrestris micro-colonies fed five diets differing in pollen species composition and level of nine essential amino acids (EAA; leucine, lysine, valine, arginine, isoleucine, phenylalanine, threonine, histidine, methionine) was assessed for 37 days by recording total biomass gain, nest building initiation, brood production (eggs, small and large larvae, pupae, drones), nectar, and pollen collection. Stronger colony performance was linked to higher amino acid levels but no consistent differences in biomass gain were recorded between mono- and poly-species diets. Poorest performance occurred in micro-colonies offered pure oilseed rape (OSR) pollen which contained the lowest EAA levels. Reduced micro-colony development (delayed nest initiation and lower brood production) was related to OSR proportion in the diet and lower EAA levels. Results are discussed in relation to selection of plant species in the design of habitats to promote bee populations

Experiments with polarized 3He at MAMI

Experiments with polarized 3He at MAMI have already a long tradition. The A3 collaboration started in 1993 with the aim to measure the electric form factor of the neutron. At this time MAMI was the second accelerator where experiments with 3He were possible. Some years before this pilot experiment the development of the apparatus to polarize 3He in Mainz started. There are two techniques which allow to polarize sufficient large quantities of 3He. Both techniques will be compared and the benefit of 3He for nuclear physics will be discussed. An review of the experiments done so far with 3He at MAMI will be given and the progress in the target development, the detector setup and the electron beam performance will be pointed out.Comment: Contribution to the Symposium "20 Years of Physics at the Mainz Microtron MAMI", to be published in Eur. Phys. Journal