Lehigh University

About: Lehigh University is a education organization based out in Bethlehem, Pennsylvania, United States. It is known for research contribution in the topics: Catalysis & Fracture mechanics. The organization has 12684 authors who have published 26550 publications receiving 770061 citations.

Understanding integrated global sourcing

Abstract: The ability to satisfy customer demands while responding to relentless competitive pressure requires creative and often complex approaches to managing a firm's supply chain. Perhaps more than any other area, executive managers increasingly believe that a concept called globalization offers the best opportunity to achieve major performance gains. One area where many companies can begin to capture the benefits of globalization is global sourcing, which involves the worldwide integration of engineering, operations, and procurement centers within the upstream portion of a firm's supply chain. Unfortunately, capturing the benefits potentially offered by globalization is often limited by a lack of understanding concerning how to pursue this important topic. To help overcome this limitation this article presents a five‐level continuum that illustrates the differences between international purchasing and global sourcing, examines the factors that are the most critical to global success, and concludes with a brief discussion of future global sourcing directions.

Nothing Succeeds Like Succession: A Critical Review of Leader Succession Literature Since 1994

Abstract: This article reviews leader succession research from 1994 to 2004. We begin with a brief summary of Kesner and Sebora’s [Kesner, I. F., & Sebora, T. C. (1994). Executive succession: Past, present and future. Journal of Management, 20, 327–372.] review of leader succession. We then critically examine intervening progress made by scholars regarding antecedents and consequences of succession. We conclude by critiquing the state of the field from both theoretical and methodological perspectives, and offering recommendations for future research. Generally, succession continues to be an attractive venue for scholars from a wide array of disciplines. Theory and methodology continue to be of variable quality, though some progress has been noted in the past decade on both fronts. Particularly notable research has generally either examined contextual aspects of succession, thus advancing our knowledge beyond main effects research, or used succession phenomena as windows into advancing organization theory.

Theory of incoherent self-focusing in biased photorefractive media

Abstract: A theory describing propagation and self-focusing of partially spatially incoherent light beams in nonlinear media is developed. It is shown that this process is effectively governed by an infinite set of coupled nonlinear Schr\"odinger-like equations, provided they are initially appropriately weighted with respect to the incoherent angular power spectrum of the source. The particular case of spatially incoherent beam propagation in biased photorefractive media is considered in detail. Numerical simulations indicate that spatial compression as well as self-trapped states are possible under appropriate conditions. Our results are in good agreement with recent experimental observations.

Prevention and Intervention with Young Children's Challenging Behavior: Perspectives regarding Current Knowledge:

Abstract: Challenging behavior exhibited by young children is becoming recognized as a serious impediment to social–emotional development and a harbinger of severe maladjustment in school and adult life. Con...

Rheological and geometric scaling of purely elastic flow instabilities

Abstract: We present a new dimensionless criterion that can be used to characterize and unify the critical conditions required for onset of purely elastic instabilities in a wide range of different flow geometries. This scaling incorporates both the presence of non-zero elastic normal stresses in the fluid plus the magnitude of the streamline curvature in the flow, and it can be thought of as the viscoelastic complement of the Gortler number. We present detailed experimental and theoretical evidence that justifies and generalizes the form of the dimensionless criterion. We show how this criterion naturally arises from the linearized stability equations governing the viscoelastic flow and apply it to analytical and experimental results in a number of standard benchmark problems. In geometrically simple flows (e.g. torsional flows such as those in a circular Couette cell or a cone-and-plate rheometer) a characteristic radius of curvature of the streamlines may be readily identified and an analytical solution for the undisturbed base flow can be found. However, in the more complex flows characteristic of those found in commercial polymer processing operations, the base flow must typically be determined numerically and the streamline curvature varies in a complex manner throughout the flow. In the former case, we show how our scaling reduces to well-established results in the literature and for the latter case we present a particularly simple approach for understanding and quantifying the sensitivity of the critical conditions for onset of elastic instability to dimensionless geometric design parameters such as the aspect ratio of the test cell. The generality of the scaling is confirmed by applying it to new experimental measurements in a lid-driven cavity and numerical linear stability calculations for flow past a cylinder in a channel. We also show how the scaling may be generalized to incorporate, at least qualitatively, the variation in the critical conditions with other rheological parameters such as changes in the solvent viscosity, shear-thinning in the viscometric functions, a spectrum of relaxation times and a non-zero second normal stress coefficient. In a number of cases, these modifications and the predicted scaling of the critical onset conditions for purely elastic instabilities in other complex geometries, such as planar contractions or eccentric rotating cylinders, remain to be confirmed by future experiments or calculations.