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Ackoff's circular structure has been successfully used to combine hierarchy and democracy in various industries. This paper argues that this structure is the most appropriate democratic structure for public schools' internal governance. A circularity of power relations between administrators and teachers would create genuinely empowering teacher participation and alleviate teacher shortages. (29 references) (MLH)

Critical scholars have often proclaimed that US colleges have failed to generate substantial levels of intellectualism among their graduates, and have emphasized career development at the expense of intellectual growth. [...]

Traditionally, ocean acoustic propagation models assume the sea surface can be treated as an idealized pressure release boundary. For flat surfaces, this can easily be accomplished through a variety of modeling techniques. Rough surfaces, however, introduce additional complexities in numerical models which assume a pressure release condition. An alternative approach is to model the physical water/air interface in a manner analogous to the water/sediment interface of the bottom. However, the ocean surface boundary introduces a much larger interface discontinuity than the bottom interface. In this work, a previously developed hybrid split-step Fourier/finite-difference approach is implemented at the water/air interface. Results are compared with standard SSF smoothing approaches. Normal mode and finite element models are utilized to provide benchmark solutions. Tradeoffs between accuracy and stability are discussed, as well as the model’s ability to accurately compute transmission across the water/air interface. [ABSTRACT FROM AUTHOR]

Even in upbeat times, educating a child or coping with the loss of a job is a sobering experience. These days, with commissions denouncing the educational system and economists warning [...]

This paper derives a spatial domain wave propagation solution of a cylindrical shell that contains periodically spaced ring stiffeners. Previous work in this area has modeled the stiffeners as having a very short or very long length. This paper models the stiffeners as finite length inclusions with forces that have spatial extent in three-dimensions. Furthermore, there is a well-defined separation distance between each stiffener. The new model uses Donnell shell equations with the stiffener forces applied in three-dimensions using Heaviside step functions. These equations of motion are orthogonalized in both the angular and longitudinal directions, resulting in a double fixed index matrix equation. These indices can be varied, which yields a set of double indexed matrix equations that are written together as a single global matrix. This global matrix can be solved, which results in a solution to the system displacements. Two specific external loading cases are investigated and convergence criteria are discussed. One of the models is verified with a comparison to finite element analysis. [ABSTRACT FROM AUTHOR]

A planewave, incident on a panel, produces an acoustic trace wavelength that propagates along the surface of the panel. The trace wavelength excites the panel into vibration, creating structural waves within the panel that propagate. These structural waves can be purposely Bragg scattered, creating replicas of the trace wavenumber. The replicas are shifted in wavenumber precisely by the inverse of the periodic separation distance ℓ. Hence, in principle, it should be possible to resolve the acoustic trace wavelength from one of the shifted replicas of the panel's response. The incident angle can then be ascertained from the replicated trace wavelengths. [ABSTRACT FROM AUTHOR]

Abstract: In this paper, we present the results of an investigation into the flow of a series of viscoelastic wormlike micelle solutions past a confined circular cylinder. Although this benchmark flow has been studied in great detail for polymer solutions, this paper reports the first experiments to use a viscoelastic wormlike micelle solution as the test fluid. The flow kinematics, stability and pressure drop were examined for two different wormlike micelle solutions over a wide range of Deborah numbers and cylinder to channel aspect ratios. A combination of particle image velocimetry and pressure drop measurements were used to characterize the flow kinematics, while flow-induced birefringence measurements were used to measure the micelle deformation and alignment in the flow. The pressure drop was found to decrease initially due to the shear thinning of the test fluid before increasing at higher flow rates as elastic effects begin to dominate the flow. Above a critical Deborah number, an elastic instability was observed for just one of the test fluids studied, the other remained stable for all Deborah number tested. Flow-induced birefringence and velocimetry measurements showed that observed instability originates in the extensional flow in the wake of the cylinder and appears not as periodic counter-rotating vortices as has been observed in the flow of polymer solutions past circular cylinders, but as a chaotic rupture event in the wake of the cylinder that propagates axially along the cylinder. Reducing the cylinder to channel aspect ratio and the degree of shearing introduced by the channel walls had a weak impact on the stability of the flow. These measurements, when taken in conjunction with previous work on flow of wormlike micelle solutions through a periodic array of cylinders, definitively show that the instability can be attributed to a breakdown of the wormlike micelle solutions in the extensional flow in the wake of the cylinder. [ABSTRACT FROM AUTHOR]

Abstract: Solutions of self-assembled wormlike micelles are used with ever increasing frequency in a multitude of consumer products ranging from cosmetic to industrial applications. Owing to the wide range of applications, flows of interest are often complex in nature; exhibiting both extensional and shear regions that can make modeling and prediction both challenging and valuable. Adding to the complexity, the micellar dynamics are continually changing, resulting in a number of interesting phenomena, such as shear banding and extensional flow instabilities. In this paper, we present the results of our investigation into the flow fields generated by a controllable and idealized porous media: a periodic array of cylinders. Our test channel geometry consists of six equally spaced cylinders, arranged perpendicular to the flow. By systematically varying the Deborah number, the flow kinematics, stability and pressure drop were measured. A combination of particle image velocimetry in conjunction with flush mount pressure transducers were used to characterize the flow, while flow induced birefringence measurements were used to determine micelle deformation and alignment. The pressure drop was found to decrease initially due to the shear thinning of the test fluid, and then exhibit a dramatic upturn as other elastic effects begin to dominate. We present evidence of the onset of an elastic instability in one of the test fluids above a critical Deborah number manifest in fluctuating transient pressure drop measurements and asymmetric streamlines. We argue that this disparity in the two test fluids can be attributed to the measurable differences in their extensional rheology. [Copyright &y& Elsevier]

Demonstrates that six major criminological perspectives, these being social control, self-control, strain, labeling, feminist, and social learning, appear to have the capacity to provide criminological accounts of Semai nonviolence that are relevant and plausible. Background information on the Semai; Findings of anthropological accounts of Semai culture; Universal socialization of their members; Revelations of previous theories of crime; Affect of these theories on the individual.

This paper classifies and analyzes the major findings of the literature concerning employee ownership in the USA utilizing Bolman and Deal's four-frame classification of the literature on organization theory, management and behavior structural, human resource, political and symbolic. It is intended to serve as a basis on which to build a comprehensive theory of employee ownership and tentatively concludes that, although employee ownership is enhancing employee participation programs at a growing number of US firms, it is not likely to have any fundamental transformative impact on a significant number of US organizations unless the USA undergoes major cultural and political changes. [ABSTRACT FROM PUBLISHER]

Under laminar, microscale flow conditions, rapid mixing can be difficult to achieve. In these low Reynolds number flows, mixing rates are governed by molecular diffusion, and in the absence of enhanced mixing techniques, mixing lengths and residence times can be much longer than most applications will allow. A number of active mixing techniques have been developed to improve mixing; however, they can be complex to implement and expensive to fabricate. In this paper, we describe a passive mixing method that utilizes a series of ultrahydrophobic surfaces. Our previous experiments have demonstrated that a shear-free air-water interface supported between hydrophobic microridges results in large slip velocities along these ultrahydrophobic surfaces, and significant drag reduction. By aligning the microridges and therefore the air-water interface at an oblique angle to the flow direction, a secondary flow is generated, which is shown to efficiently stretch and fold the fluid elements and reduce the mixing length by more than an order of magnitude compared to that of a smooth microchannel. The designs of the ultrahydrophobic surfaces were optimized through experiments and numerical simulations. A Y-shaped channel was used to bring two streams of water together, one tagged with a fluorescent dye. A confocal microscope was used to measure fluorescence intensity and dye concentration. Quantitative agreement between the experiments and the numerical simulations was achieved for both the flow patterns and degree of mixing. Increasing the angle of the microridges was found to reduce the mixing length up to a critical angle of about 60 degrees , beyond which the mixing length was found to increase with further increases to the angle of the microridge. The mixing enhancement was found to be much less sensitive to changes in microridge width or separation.