Solution of viscous transonic flow over wings

Knowledge of the viscous flow about wings is very important in 3-D wing design. In transonic flow about a typical supercritical wing, the viscous effect results in a sizable reduction of the lift-to-drag ratio. The Reynolds number dependence of the flow is not clearly defined, and no known similitude exists that can be used to scale the experimental data for a particular design. Recent advances in computer technology and numerical technique have relieved the difficulty of obtaining a theoretical solution somewhat, but the lack of a proper reliable method of treating the turbulence in a time-averaged Navier-Stokes solution remains the major stumbling block.For this paper, a “zonal” approach has been used for a viscid-inviscid interaction analysis to yield an iterative solution for the viscous flow about wings in the transonic flow regime. The chord Reynolds number considered was of the order of 10⁶ and above so that the flow was predominantly turbulent. The inviscid flow field was obtained by solving the 3-D potential flow equation. A parabolic coordinate mapping was used in the computation, in conjunction with a finite volume formulation. A new approximate factorization scheme has been developed for the iterative solution of the inviscid flow. A special far field asymptotic boundary condition that improves the accuracy and convergence of the method was derived. For the 3-D boundary layer calculation, the integral method of Myring-Smith-Stock was extensively modified to make it suitable for the interaction calculation. The effect of wing thickness was taken into account and the 3-D viscous wake was computed. The interaction calculation was formulated with a set of coupling conditions that includes the source flux distribution due to the surface boundary layer on the wing, the flux jump distribution due to the viscous wake, and the effect of the viscous wake curvature. The transpiration boundary conditions have been used for the inviscid flow in the coupled calculation. In addition, a method was devised so that the results of an analysis of the trailing edge strong interaction solution for a 2-D viscous airfoil could be adapted for the normal pressure correction near the trailing edge. The theory has been applied to supercritical wing geometries of practical interest. The converged viscous flow results compare favorably with experimental pressure data.     

Prospective intervention opportunities regarding device ownership and the reduction of damage to handheld ruggedized devices with shift workers

Industrial equipment such as ruggedized handheld computers, scanners, and label printers used within asset tracking environments are expensive to purchase and costly to repair. For organizations that use this equipment, there is value in understanding when and why damage occurs and how much of those costs are potentially associated with the employees’ own sense of psychological ownership and organizational pride. Given the connection between psychological ownership and pride, the purpose of this study was to analyze employee surveys to determine what methods, tools, or programs could reduce repair and replacement while developing a stronger sense of ownership for ruggedized devices used in material‐handling industries by shift workers. Unstructured interviews about device repair with management from a large industrial company were utilized to create a multiple‐choice, anonymous online survey (n = 353). Of the six interventions proposed, assigning the same device to the same employee every shift appeared to have the most consistent and positive response. Destruction rates and costs should be posted for employee viewing and managers of workgroups with consistently high destruction rates should receive additional training. An incentive‐based program for employees responsible for the least amount of device damage as well as an individual‐assignment of devices to employees may be considered. Applications for this student include providing a tool with which organizations can use to gauge employee ownership of equipment as well as to identify interventions that may aid in mitigating expenses associated with industrially rugged equipment.     

Ultraviolet spectrophotometric characteristics of unhydrogenated fish oils

Summary Typical ultraviolet spectrophotometric absorption curves are presented for unhydrogenated fish oils of commercial importance, before and after alkali isomerization. These curves show the usual maxima for isomerized polyunsaturated fatty acids, including five, and possibly six, double bonds. Tetraene absorption is sufficient to obliterate that of trienes completely. Such a method of analysis affords an easy means of detecting unhydrogenated fish oil contamination in the ordinary vegetable and animal oils and fats as well as a test for the presence of fish oils in admixture with raw linseed oil. Presented at 39th annual meeting of the American Oil Chemists' Society, New Orleans, La., May 4–6, 1948.     

Presence of Escherichia coli O157:H7, Listeria monocytogenes and Salmonella spp. in food from animal origin in Costa Rica

The presence of Escherichia coli O157:H7, Listeria monocytogenes and Salmonella spp was analyzed in two kinds of food from animal origin in Costa Rica. 100 samples of non pasteurized milk, from the principal producing zones of the country, and 100 samples of chicken giblets, purchased in retail markets, were analyzed according to the methodology described by Food and Drug Administration, 1995. Escherichia coli O157:H7 was analyzed in both kinds of food, while L. monocytogenes was evaluated in raw milk and Salmonella spp. in chicken giblets. Five strains of E. coli O157:H7 were isolated, three of them coming from chicken giblets and the other two from raw milk. 15% positivity for Salmonella spp. was found in chicken giblet samples and 3% positivity for L. monocytogenes in raw milk samples. The results obtained show the importance of the adequate processing of food from animal origin in order to decrease the potential transmission of pathogenic agents. The introduction of Hazard Analysis Critical Control Points system (HACCP) and Good Manufacturing practices in food industry keep on being the principal control measures and inocuity warranty.     

Atomistic aspects of ductile responses of cubic silicon carbide during nanometric cutting

Cubic silicon carbide (SiC) is an extremely hard and brittle material having unique blend of material properties which makes it suitable candidate for microelectromechanical systems and nanoelectromechanical systems applications. Although, SiC can be machined in ductile regime at nanoscale through single-point diamond turning process, the root cause of the ductile response of SiC has not been understood yet which impedes significant exploitation of this ceramic material. In this paper, molecular dynamics simulation has been carried out to investigate the atomistic aspects of ductile response of SiC during nanometric cutting process. Simulation results show that cubic SiC undergoes sp³-sp² order-disorder transition resulting in the formation of SiC-graphene-like substance with a growth rate dependent on the cutting conditions. The disorder transition of SiC causes the ductile response during its nanometric cutting operations. It was further found out that the continuous abrasive action between the diamond tool and SiC causes simultaneous sp³-sp² order-disorder transition of diamond tool which results in graphitization of diamond and consequent tool wear.     

AE Monitoring and Analysis of HVOF Thermal Spraying Process

This work presents an in situ monitoring of HVOF thermal spraying process through an acoustic emission (AE) technique in an industrial coating chamber. Single layer thermal spraying on substrate was carried out through slits. Continuous multilayer thermal spraying onto the sample without slit was also conducted. The AE was measured using a broadband piezoelectric AE sensor positioned on the back of the substrate. A mathematical model has been developed to determine the total kinetic energy of particles impacting the substrate through slits. Results of this work demonstrate that AE associated with particle impacts can be used for in situ monitoring of coating process. Results also show that the amplitude and AE energy is related to the spray gun transverse speed and the oxy-fuel pressure. The measured AE energy was found to vary with the number of particles impacting the substrate, determined using the mathematical model.     

X-ray photoelectron spectroscopic investigation of the durability of siloxane plasma polymer coatings in a steam atmosphere

Thin-film plasma polymer coatings were deposited on to titanium, stainless steel and 70/30 copper-nickel substrates from hexamethyldisiloxane (HMDSO) as potential permanent promoters of dropwise condensation of steam. Long-term durability condensation tests showed that HMDSO films on titanium exposed to low-velocity steam performed well with some lifetimes in excess of 12 000 h. X-ray photoelectron spectroscopy (XPS) was used to monitor the dependence of chemical composition of the films on the deposition conditions and it was shown that composition was not critically dependent on deposition conditions. Additionally, XPS was used to monitor chemical composition before and after exposure of specimens to steam in an attempt to identify the failure mechanisms for films which had ceased to sustain dropwise condensation over their entire surface. Furthermore, short tube sections were coated with plasma-polymerized HMDSO and exposed to steam at elevated velocities. In this case the durability was poor and this is attributed to water droplet impingement erosion on the tube surfaces. This was confirmed by a subsequent test where no water droplets were present in the steam flow and the coating lifetime was seen to increase.     

Review of What works for whom? A critical review of psychotherapy research.

Reviews the book, What works for whom? A critical review of psychotherapy research by Anthony Roth and Peter Fonagy (see record 1996-98691-000). This book presents a comprehensive review of the status of psychotherapy research. The authors look at the evidence dealing with both efficacy and effectiveness of psychotherapy for the more common DSM-IV disorders. All of the chapters are geared toward the goal of providing the practitioner with a list of treatments for which there is empirical support. The reviewer notes that the amount of information covered in this text is extensive and provides sufficient evidence for the efficacy of psychotherapy for many of the diagnostic categories. Despite an overemphasis on cognitive/behavioral treatments, the authors do present the best of the research in psychodynamic therapy. The reviewer recommends this volume to both to researchers and practitioners. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

An ecological perspective on integrating personality and social psychology.

We use the Gibsonian ecological construct of affordance to integrate personality and social psychology. Illustrative applications include the interpersonal implications of depression, the nature of social competence, the meaning of traits, and various aspects of the structure and function of attitudes. We also use the affordance concept to derive a lock-and-key metaphor for integrating personality and social psychology. (PsycINFO Database Record (c) 2010 APA, all rights reserved)