Development of optimized, graded-permeability axial groove heat pipes

Heat pipe performance can usually be improved by uniformly varying or grading wick permeability from end to end. A unique and cost effective method for grading the permeability of an axial groove heat pipe is described - selective chemical etching of the pipe casing. This method was developed and demonstrated on a proof-of-concept test article. The process improved the test article's performance by 50 percent. Further improvement is possible through the use of optimally etched grooves

Continuous and first-order jamming transition in crossing pedestrian traffic flows

After reviewing the main results obtained within a model for the intersection of two perpendicular flows of pedestrians, we present a new finding: the changeover of the jamming transition from continuous to first order when the size of the intersection area increases.Comment: 14 pages, 9 figure

Exact domain wall theory for deterministic TASEP with parallel update

Domain wall theory (DWT) has proved to be a powerful tool for the analysis of one-dimensional transport processes. A simple version of it was found very accurate for the Totally Asymmetric Simple Exclusion Process (TASEP) with random sequential update. However, a general implementation of DWT is still missing in the case of updates with less fluctuations, which are often more relevant for applications. Here we develop an exact DWT for TASEP with parallel update and deterministic (p=1) bulk motion. Remarkably, the dynamics of this system can be described by the motion of a domain wall not only on the coarse-grained level but also exactly on the microscopic scale for arbitrary system size. All properties of this TASEP, time-dependent and stationary, are shown to follow from the solution of a bivariate master equation whose variables are not only the position but also the velocity of the domain wall. In the continuum limit this exactly soluble model then allows us to perform a first principle derivation of a Fokker-Planck equation for the position of the wall. The diffusion constant appearing in this equation differs from the one obtained with the traditional `simple' DWT.Comment: 5 pages, 4 figure

Crossing pedestrian traffic flows,diagonal stripe pattern, and chevron effect

We study two perpendicular intersecting flows of pedestrians. The latter are represented either by moving hard core particles of two types, eastbound (\symbp) and northbound (\symbm), or by two density fields, \rhop_t(\brr) and \rhom_t(\brr). Each flow takes place on a lattice strip of width $M$ so that the intersection is an $M\times M$ square. We investigate the spontaneous formation, observed experimentally and in simulations, of a diagonal pattern of stripes in which alternatingly one of the two particle types dominates. By a linear stability analysis of the field equations we show how this pattern formation comes about. We focus on the observation, reported recently, that the striped pattern actually consists of chevrons rather than straight lines. We demonstrate that this `chevron effect' occurs both in particle simulations with various different update schemes and in field simulations. We quantify the effect in terms of the chevron angle $\Delta\theta_0$ and determine its dependency on the parameters governing the boundary conditions.Comment: 36 pages, 22 figure

Challenging the Installed Base: Deploying a Large Scale IS in a Global Organization

Economic theory and business strategists have pointed at the phenomenon of positive externalities and the related enabling and constraining aspects of an installed base. For instance, in the development of a standards strategy for technology products these externalities are of profound importance [11]. Likewise, deployment of large-scale IS creates interdependencies horizontally throughout the organization, and are constrained by a continuously evolving and socio-technical installed base of information, systems, artifacts, practices, and organizational structures. This paper draws from a case study of a global company and illuminates the role of an installed base in relation to the organizing visions in the deployment of a large-scale IS. The case illustrates that deployment of a large-scale IS in a global company is likely to be more similar to the development of infrastructures than traditional IS development and ITstrategy planning

Some Information Systems Research Trends over the Past Decade

In order to gain an understanding of the recent evolution and the current state of information systems (IS) development research, three sub-topic areas within IS development, were examined: IS development methodology, IS architecture, and IS design and modeling. Relevant papers were selected from the Association for Information Systems (AIS) basket of eight journals. Using these articles, an empirical method based on author keywords was used to identify categorical research trends in each of the three areas. Research trends observed in each of the categories over the past decade are discussed

The issue of competence in transforming the Norwegian welfare sector: some implications for future e-government initiatives

In this paper we argue that e-government initiatives need to take the competence involved in producing high-quality services for citizens into account. We draw on insights from a Pilot project in a Norwegian municipal aiming at radically re-structuring the Norwegian welfare sector and show how the competence to provide high-quality services rely on the collective achievement of individuals’ knowing-in-practice when dealing with particular cases and situations. Furthermore, we show how competence in terms of ‘processes of knowing’ is intrinsically related to organization structure and existing information systems (IS). Transforming the Norwegian Welfare Sector then, involves transforming a socio-technical network of heterogeneous elements, where existing processes of knowing plays an important role. Based on this, we then discuss some implications for implementing e-government in local municipals, and in particular e-government initiatives that aim at introducing all-embracing integrated IT-solutions across organizational and geographical borders. The paper concludes by sketching some implications for future research on e-government