Symmetry Analysis in Linear Hydrodynamic Stability Theory: Classical and New Modes in Linear Shear

We present a symmetry classification of the linearised Navier-Stokes equations for a two-dimensional unbounded linear shear flow of an incompressible fluid. The full set of symmetries is employed to systematically derive invariant ansatz functions. The symmetry analysis grasps three approaches. Two of them are existing ones, representing the classical normal modes and the Kelvin modes, while the third is a novel approach and leads to a new closed-form solution of traveling modes, showing qualitatively different behaviour in energetics, shape and kinematics when compared to the classical approaches. The last modes are energy conserving in the inviscid case. They are localized in the cross-stream direction and periodic in the streamwise direction. As for the kinematics, they travel at constant velocity in the cross-stream direction, whilst in the streamwise direction they are accelerated by the base flow. In the viscous case, the modes break down due to damping of high wavenumber contributions

The asymptotics of the moving contact line: cracking an old nut

This article has been published in a revised form in Journal of Fluid Mechanics https://doi.org/10.1017/jfm.2014.702. This version is free to view and download for private research and study only. Not for re-distribution, re-sale or use in derivative works. © Cambridge University Press.For contact line motion where the full Stokes flow equations hold, full matched asymptotic solutions using slip models have been obtained for droplet spreading and more general geometries. These solutions to the singular perturbation problem in the slip length, however, all involve matching through an intermediate region that is taken to be separate from the outer-inner regions. Here, we show that the intermediate region is in fact an overlap region representing extensions of both the outer and the inner region, allowing direct matching to proceed. In particular, we investigate in detail how a previously seen result of the matching of the cubes of the free surface slope is justified in the lubrication setting. We also extend this two-region direct matching to the more general Stokes flow case, offering a new perspective on the asymptotics of the moving contact line problem

The contact line behaviour of solid-liquid-gas diffuse-interface models

A solid-liquid-gas moving contact line is considered through a diffuse-interface model with the classical boundary condition of no-slip at the solid surface. Examination of the asymptotic behaviour as the contact line is approached shows that the relaxation of the classical model of a sharp liquid-gas interface, whilst retaining the no-slip condition, resolves the stress and pressure singularities associated with the moving contact line problem while the fluid velocity is well defined (not multi-valued). The moving contact line behaviour is analysed for a general problem relevant for any density dependent dynamic viscosity and volume viscosity, and for general microscopic contact angle and double well free-energy forms. Away from the contact line, analysis of the diffuse-interface model shows that the Navier--Stokes equations and classical interfacial boundary conditions are obtained at leading order in the sharp-interface limit, justifying the creeping flow problem imposed in an intermediate region in the seminal work of Seppecher [Int. J. Eng. Sci. 34, 977--992 (1996)]. Corrections to Seppecher's work are given, as an incorrect solution form was originally used.Comment: 33 pages, 3 figure

Effectiveness of Pork Quality Assurance Training for Youth

Over 3,500 youth in Nebraska were trained and certified in Pork Quality Assurance (PQA) in 1999. Quality assurance training had an impact on the youths’ opinions about quality assurance and consumers and on the youths’ knowledge of quality assurance practices. Emphasis on character development and decision-making skills translated into positive responses about the responsibilities of a livestock producer to animals and consumers. While most youth understood at least some of their responsibilities prior to completing the training, the quality assurance training served to reinforce the understanding of those youth and also to help all youth recognize the breadth of the responsibilities that they have as livestock producers. Educating youth about quality assurance will also benefit the livestock industry. The youths’ knowledge of quality assurance practices will strengthen the livestock industry’s standards for producing safe and wholesome food products, both currently and in the future. While the livestock produced by these youth may not represent a large proportion of today’s livestock industry, the youth themselves represent the future of the livestock industry. Only a small proportion may be directly involved in production and use their skills in that manner, but all will be consumers. Food safety has been and will continue to be an issue to consumers. These youth will be consumers and should have a better appreciation and understanding of the measures that livestock producers take to ensure a safe, high quality, and wholesome food supply

On the moving contact line singularity: Asymptotics of a diffuse-interface model

The behaviour of a solid-liquid-gas system near the three-phase contact line is considered using a diffuse-interface model with no-slip at the solid and where the fluid phase is specified by a continuous density field. Relaxation of the classical approach of a sharp liquid-gas interface and careful examination of the asymptotic behaviour as the contact line is approached is shown to resolve the stress and pressure singularities associated with the moving contact line problem. Various features of the model are scrutinised, alongside extensions to incorporate slip, finite-time relaxation of the chemical potential, or a precursor film at the wall.Comment: 14 pages, 3 figure

LOW-POWER DEVICE OPERATION

An electronic device sleep mode system places an Internet connected electronic device in a low-power “sleep” mode. The system identifies a battery level of the Internet connected electronic device. When the system determines that the battery level has reached a predetermined low battery threshold, the system wirelessly transmits a notification indicating the low battery level to a user of the Internet connected electronic device. After transmitting the notification, the system places the device in a low-power sleep mode. In the low-power sleep mode, the system switches off all wireless connection radios of the device such as WiFi, 3G, etc. The system also stops any active background operations such as: suspending downloads, suspending device upgrade activity. The system also suspends activities that might demand high processing power

Evaluation of Growth Performance, Energy Utilization, and Carcass Trait Responses of Finishing Lambs Administered Zeranol

The objective of this research was to determine the influence of implanting heavy wether lambs with 12 mg zeranol (1 pellet Ralgro, Merck Animal Health. Madison, NJ) 59 d before harvest. Average daily gain (ADG), feed efficiency, and carcass merit were evaluated. Polpypay and crossbred wethers (n = 32 total) were equally divided into two treatment groups within a randomized complete block design. Sixteen pens were used resulting in 8 replicate pens per treatment. Wethers were fed a finishing diet consisting of cracked corn, soybean meal and soybean hulls ad libitum for 59 d. Lambs had access to clean water at all times from water fountains. Lambs were weighed on d 0, 1, 14, and 59 lambs. On d 59, 16 lambs (8 lambs/treatment) were harvested in the South Dakota State University Meat Lab. Hot carcass weight (HCW), dressing percent (DP), rib fat, body wall thickness, ribeye area, boneless closely trimmed retail cut percentages and yield grades were recorded. Final body weight (BW), cumulative ADG and gain efficiency were greater (P ≤ 0.01) for implanted lambs by 2.9%, 25.0%, and 35.2%, while dry matter intake (DMI) was not appreciably influenced by implant treatment (P = 0.18). No appreciable differences were noted (P ≥ 0.17) between treatments for any carcass traits measured. These results indicate that zeranol improves growth performance without detriment to carcass quality which implies that producers can improve profitability due to increased gains and efficiency

Dynamic Capabilities for People-Centric Management in Turbulent Times

We have all observed examples of poor leaders who exhibit dark side behaviors like destructive and negative leadership, narcissism, greed, and more. Sometimes it seems like some powerful Sith Lord from Star Wars has seduced managers and leaders to the Dark Side of The Force. Powerful forces inside and outside of the organization combined with the leader’s personality traits can combine to bring out the dark side of many managers and leaders. The question becomes, can a management structure be created to combat the Sith Lord to make good leaders Jedi Knights and steer weaker leaders toward the good side of The Force. We believe that a people-centric approach to management design can do exactly that, but it is not easy. Developing the dynamic capabilities needed for a people-centric approach to management requires reflection and objective evaluation of many intangible, unseen, forces that are constantly at work in all organizations. Readers of this chapter are exposed to a model for people-centric management and asked probing questions to encourage them to consider many elements of a dynamic people-centric organization. I hope that with reflection, readers can gain insight into their organizations and find ways to develop Jedi Knights to defeat the evil Sith Lord