502 research outputs found
Influence of Beef Carcass Weight on Carcass Chilling, Steak Case Life and Quality Traits
The objective of this thesis was to determine the influence of beef carcass weight on chilling and pH decline of beef carcasses, as well as color, case life and tenderness of steaks from the round, loin, rib and chuck. Twelve carcasses were allotted by hot carcass weight (HCW) into Heavyweight (HW) and Lightweight (LW) groups. Temperature decline, pH decline and thermal image temperature were measured in the round, loin, rib, and chuck for approximately 48 hours. Carcass data including 12th rib fat thickness, ribeye area, and marbling score were collected. The Semitendinosus (ST), Longissimus lumborum (LL), Longissimus thoracis (LT) and the Serratus ventralis (SV) were removed, weighed, cut into steaks for assessment of instrumental color, sensory color and Warner-Bratzler Shear Force (WBSF) analysis. HW carcasses had heavier (P \u3c 0.05) HCW and muscle weights compared to LW. No HCW × time or HCW main effects (P \u3e 0.05) were observed for pH decline. Ribs from HW had increased temperatures (P \u3c 0.05) the first 25 h of chilling compared to LW but were similar for remainder of chilling period (P \u3e 0.05). Temperature in the round was similar for the first 3 h of chilling (P \u3e 0.05), but HW had increased temperatures for remainder of chilling (P \u3c 0.05). Steaks from the ST of LW were more tender (P \u3c 0.05) than HW at d 5, but were similar at d 10, 14 and 21 (P \u3e 0.05). Steaks from the ST of HW were darker (P \u3c 0.05) throughout the display period. On d 1 of retail display, ST steaks from HW carcasses had decreased L* value (P \u3c 0.05), whereas the LW increased (P \u3c 0.05). Steaks from the ST of HW had lower a* and b* values (P \u3c 0.05) than LW. Steaks from the SV of HW had lower subjective color scores (P \u3c 0.05) compared to LW. These data suggest the slower temperature decline observed in HW carcasses can result in some negative meat quality traits. However, further research is needed to understand the influence of HCW on chilling time and meat quality outcomes
Development of a Common Research Model for Applied CFD Validation Studies
The development of a wing/body/nacelle/pylon/horizontal-tail configuration for a common research model is presented, with focus on the aerodynamic design of the wing. Here, a contemporary transonic supercritical wing design is developed with aerodynamic characteristics that are well behaved and of high performance for configurations with and without the nacelle/pylon group. The horizontal tail is robustly designed for dive Mach number conditions and is suitably sized for typical stability and control requirements. The fuselage is representative of a wide/body commercial transport aircraft; it includes a wing-body fairing, as well as a scrubbing seal for the horizontal tail. The nacelle is a single-cowl, high by-pass-ratio, flow-through design with an exit area sized to achieve a natural unforced mass-flow-ratio typical of commercial aircraft engines at cruise. The simplicity of this un-bifurcated nacelle geometry will facilitate grid generation efforts of subsequent CFD validation exercises. Detailed aerodynamic performance data has been generated for this model; however, this information is presented in such a manner as to not bias CFD predictions planned for the fourth AIAA CFD Drag Prediction Workshop, which incorporates this common research model into its blind test cases. The CFD results presented include wing pressure distributions with and without the nacelle/pylon, ML/D trend lines, and drag-divergence curves; the design point for the wing/body configuration is within 1% of its max-ML/D. Plans to test the common research model in the National Transonic Facility and the Ames 11-ft wind tunnels are also discussed
Influence of Beef Carcass Chilling Rate on Steak Case Life and Quality Traits
Objective To determine if beef carcass weight influences chilling rate, pH decline, beef color, case life and tenderness of steaks from the round, loin, rib and chuck
Drag Prediction for the NASA CRM Wing-Body-Tail Using CFL3D and OVERFLOW on an Overset Mesh
In response to the fourth AIAA CFD Drag Prediction Workshop (DPW-IV), the NASA Common Research Model (CRM) wing-body and wing-body-tail configurations are analyzed using the Reynolds-averaged Navier-Stokes (RANS) flow solvers CFL3D and OVERFLOW. Two families of structured, overset grids are built for DPW-IV. Grid Family 1 (GF1) consists of a coarse (7.2 million), medium (16.9 million), fine (56.5 million), and extra-fine (189.4 million) mesh. Grid Family 2 (GF2) is an extension of the first and includes a superfine (714.2 million) and an ultra-fine (2.4 billion) mesh. The medium grid anchors both families with an established build process for accurate cruise drag prediction studies. This base mesh is coarsened and enhanced to form a set of parametrically equivalent grids that increase in size by a factor of roughly 3.4 from one level to the next denser level. Both CFL3D and OVERFLOW are run on GF1 using a consistent numerical approach. Additional OVERFLOW runs are made to study effects of differencing scheme and turbulence model on GF1 and to obtain results for GF2. All CFD results are post-processed using Richardson extrapolation, and approximate grid-converged values of drag are compared. The medium grid is also used to compute a trimmed drag polar for both codes
Incorporating Inductances in Tissue-Scale Models of Cardiac Electrophysiology
In standard models of cardiac electrophysiology, including the bidomain and
monodomain models, local perturbations can propagate at infinite speed. We
address this unrealistic property by developing a hyperbolic bidomain model
that is based on a generalization of Ohm's law with a Cattaneo-type model for
the fluxes. Further, we obtain a hyperbolic monodomain model in the case that
the intracellular and extracellular conductivity tensors have the same
anisotropy ratio. In one spatial dimension, the hyperbolic monodomain model is
equivalent to a cable model that includes axial inductances, and the relaxation
times of the Cattaneo fluxes are strictly related to these inductances. A
purely linear analysis shows that the inductances are negligible, but models of
cardiac electrophysiology are highly nonlinear, and linear predictions may not
capture the fully nonlinear dynamics. In fact, contrary to the linear analysis,
we show that for simple nonlinear ionic models, an increase in conduction
velocity is obtained for small and moderate values of the relaxation time. A
similar behavior is also demonstrated with biophysically detailed ionic models.
Using the Fenton-Karma model along with a low-order finite element spatial
discretization, we numerically analyze differences between the standard
monodomain model and the hyperbolic monodomain model. In a simple benchmark
test, we show that the propagation of the action potential is strongly
influenced by the alignment of the fibers with respect to the mesh in both the
parabolic and hyperbolic models when using relatively coarse spatial
discretizations. Accurate predictions of the conduction velocity require
computational mesh spacings on the order of a single cardiac cell. We also
compare the two formulations in the case of spiral break up and atrial
fibrillation in an anatomically detailed model of the left atrium, and [...].Comment: 20 pages, 12 figure
Influence of Carcass Chilling System on Chuck, Loin, and Round Temperature Decline, Carcass Characteristics, and Tenderness
Objective Determine the effect of chilling systems on beef carcass temperature decline, carcass characteristics, and tenderness
Drag Prediction for the DLR-F6 Wing/Body and DPW Wing using CFL3D and OVERFLOW Overset Mesh
A series of overset grids was generated in response to the 3rd AIAA CFD Drag Prediction Workshop (DPW-III) which preceded the 25th Applied Aerodynamics Conference in June 2006. DPW-III focused on accurate drag prediction for wing/body and wing-alone configurations. The grid series built for each configuration consists of a coarse, medium, fine, and extra-fine mesh. The medium mesh is first constructed using the current state of best practices for overset grid generation. The medium mesh is then coarsened and enhanced by applying a factor of 1.5 to each (I,J,K) dimension. The resulting set of parametrically equivalent grids increase in size by a factor of roughly 3.5 from one level to the next denser level. CFD simulations were performed on the overset grids using two different RANS flow solvers: CFL3D and OVERFLOW. The results were post-processed using Richardson extrapolation to approximate grid converged values of lift, drag, pitching moment, and angle-of-attack at the design condition. This technique appears to work well if the solution does not contain large regions of separated flow (similar to that seen n the DLR-F6 results) and appropriate grid densities are selected. The extra-fine grid data helped to establish asymptotic grid convergence for both the OVERFLOW FX2B wing/body results and the OVERFLOW DPW-W1/W2 wing-alone results. More CFL3D data is needed to establish grid convergence trends. The medium grid was utilized beyond the grid convergence study by running each configuration at several angles-of-attack so drag polars and lift/pitching moment curves could be evaluated. The alpha sweep results are used to compare data across configurations as well as across flow solvers. With the exception of the wing/body drag polar, the two codes compare well qualitatively showing consistent incremental trends and similar wing pressure comparisons
Three Way Comparison between Two OMI/Aura and One POLDER/PARASOL Cloud Pressure Products
The cloud pressures determined by three different algorithms, operating on reflectances measured by two space-borne instruments in the "A" train, are compared with each other. The retrieval algorithms are based on absorption in the oxygen A-band near 760 nm, absorption by a collision induced absorption in oxygen near 477nm, and the filling in of Fraunhofer lines by rotational Raman scattering. The first algorithm operates on data collected by the POLDER instrument on board PARASOL, while the latter two operate on data from the OMI instrument on board Aura. The satellites sample the same air mass within about 15 minutes. Using one month of data, the cloud pressures from the three algorithms are found to show a similar behavior, with correlation coefficients larger than 0.85 between the data sets for thick clouds. The average differences in the cloud pressure are also small, between 2 and 45 hPa, for the whole data set. For optically thin to medium thick clouds, the cloud pressure the distribution found by POLDER is very similar to that found by OMI using the O2 - O2 absorption. Somewhat larger differences are found for very thick clouds, and we hypothesise that the strong absorption in the oxygen A-band causes the POLDER instrument to retrieve lower pressures for those scenes
Characteristics of Academic Anesthesiologist’s Elected to an Institutional Academy of Master Educators
Background. The educational experience and success of academic anesthesiologists may be elusive to quantify. We wished to examine the characteristics of a cohort of anesthesiology faculty who were inducted into a medical school master educator academy over the last decade.
Methods. After IRB approval with waiver of consent, all 10 anesthesiology faculty inductees into the academy supplied relevant data for their accomplishments at the time of induction in multiple educational domains, including teaching and assessment, mentoring and advising, evidence of scholarship and production of enduring materials, and educational leadership. These were deidentified and analyzed.
Results. The cohort had evidence of a consistent, visible footprint in the department, medical school, affiliated associations and state and national professional organizations. These included educational leadership positions, numerous teaching recognition and awards, substantial committee service, active mentorship exceeding usual faculty effort and robust portfolios of publications and presentations related to teaching and/or incorporating and supporting mentees as co-authors. Neither time in rank or academic progress was a limitation with several achieving induction in \u3c 5 years.
Conclusions. It is possible for full-time anesthesiology clinicians to achieve success in educational recognition within the medical school body. This summary of characteristics of one department’s cohort may be useful to others seeking such recognition and serve. Based on the aggregate findings, we make recommendations for faculty wishing to pursue excellence in education
Potential of a cyclone prototype spacer to improve in vitro dry powder delivery
Copyright The Author(s) 2013. This article is published with open access at Springerlink.com. This article is distributed under the terms of the Creative Commons Attribution License which permits any use, distribution, and reproduction in any medium, provided the original author(s) and the source are creditedPurpose: Low inspiratory force in patients with lung disease is associated with poor deagglomeration and high throat deposition when using dry powder inhalers (DPIs). The potential of two reverse flow cyclone prototypes as spacers for commercial carrierbased DPIs was investigated. Methods: Cyclohaler®, Accuhaler® and Easyhaler® were tested with and without the spacers between 30-60 Lmin-1. Deposition of particles in the next generation impactor and within the devices was determined by high performance liquid chromatography. Results: Reduced induction port deposition of the emitted particles from the cyclones was observed due to the high retention of the drug within the spacers (e.g. salbutamol sulphate (SS): 67.89 ± 6.51 % at 30 Lmin-1 in Cheng 1). Fine particle fractions of aerosol as emitted from the cyclones were substantially higher than the DPIs alone. Moreover, the aerodynamic diameters of particles emitted from the cyclones were halved compared to the DPIs alone (e.g. SS from the Cyclohaler® at 4 kPa: 1.08 ± 0.05 μm vs. 3.00 ± 0.12 μm, with and without Cheng 2, respectively) and unaltered with increased flow rates. Conclusion: This work has shown the potential of employing a cyclone spacer for commercial carrier-based DPIs to improve inhaled drug delivery.Peer reviewe
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