Project Organizations as Social Networks

High-performance teams achieve outcomes that exceed the expectations of the project and often demonstrate unique or innovative approaches within a final solution. The foundation of this high performance is the ability to focus on the success of the team over individual objectives. However, the recognition of this emphasis is based on the establishment of professional trust and strong communications between the team members. The social network model of construction introduced a dual-focused approach to enhancing these elements and creating high-performance project teams. The approach emphasizes balancing both a traditional project management emphasis on efficiency of communications with a focus on the social factors that move the project team from efficient to effective. In this paper, the model is extended to present the results of four studies of organizations that are full-service engineering companies that also provide construction oversight services. The paper presents the results of these studies in terms of the social network model and the achievement of high performance in the project teams. Analytical and graphical results are presented based on social network analysis techniques to provide a multiperspective analysis of the project teams.     

On Floating‐Point Normal Vectors

In this paper we analyze normal vector representations. We derive the error of the most widely used representation, namely 3D floating‐point normal vectors. Based on this analysis, we show that, in theory, the discretization error inherent to single precision floating‐point normals can be achieved by 2^50.2 uniformly distributed normals, addressable by 51 bits. We review common sphere parameterizations and show that octahedron normal vectors perform best: they are fast and stable to compute, have a controllable error, and require only 1 bit more than the theoretical optimal discretization with the same error.     

Simulation of Fluid Flow and Oscillation of the Argon Oxygen Decarburization (AOD) Process

The oscillation of argon oxygen decarburization (AOD) converters is flow related and depends on the process parameters (e.g., vessel geometry, melt fill height, process gas type and blowing rate, vessel tilting angle, as well as geometry, number, and arrangement of the side-wall nozzles). For a 120-ton AOD converter with seven submerged side-wall nozzles, plant tests, physical simulations on a 1:4 scale water model, and computational fluid dynamics simulations have been done. The investigations show that the penetration depth of an inert gas jet into the melt does not exceed approximately 0.4 m. The plumes are located close to the nozzle-side converter wall and induce a large-scale primary vortex as well as intensive surface movements; both are responsible for the oscillation. Several process mechanisms were investigated. The oscillation is highest in the last stage of the dynamic blow and is still high during the reduction stage. As the amount of inert gas increases, the vibration level also increases. Inert gas has a greater influence on the oscillation than oxygen. Tilting the converter around 8 deg clearly leads to more intensive oscillations. Increasing the blowing rate increases the forces and torques acting on the vessel, whereas the oscillation frequency remains nearly constant. A varying fill level does not influence the vibration level the same way as the blowing rate. The operational test shows, for example, that the maximum torque does not depend on the heat size when the latter varies between –8 pct and +21 pct of the nominal heat size. The water model test shows decreasing forces and torques with a rising fill level.     

Direct comparison between hot pressing and electric field-assisted sintering of submicron alumina

This study compares hot pressing (HP) and the electric field-assisted sintering technique (FAST) of two different electrically insulating Al₂O₃ submicron powders with median particle sizes of 150 and 500 nm. Sample geometry, heating schedule, applied pressure and atmosphere were identical for both sintering methods. The densification behavior and characterization of the microstructure revealed that FAST sintered samples reached a higher density compared with HP, in particular for the finer powder. It was found that an increase in dwell time was required to reach the same final density by HP. However, analysis of the sintering curves showed that the densification mechanism for both sintering methods was grain boundary diffusion. Increasing the heating rate up to 150 K min^?1 did not modify the densification mechanism. The sintering trajectory showed that the grain size was only dependent on density and was insensitive to the sintering method, in addition to showing a lack of preferential grain orientation.     

Vorwort der Herausgeber

Ohne Zusammenfassung     

Personal self-regulation of development: Cross-sequential analyses of development-related control beliefs and emotions.

This study is part of a larger research project centering on personal self-regulation of development in adulthood. Cross-sectional, longitudinal, and correlational findings are presented for selected parameters of personal development (subjective developmental attainment, self-corrective tendency, personal control over development, depressive outlook on personal development, and perceived marital support) derived from questionnaire data. The findings highlight the importance of development-related control efforts and beliefs for achieving a subjectively favorable balance of developmental gains and losses and for maintaining an optimistic perspective in middle and later adulthood. Results are discussed with reference to a theoretical model of development-related control activities. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Integrating Scientometric Indicators into Sociological Studies: Methodical and Methodological Problems

This article discusses the methodological problems of integrating scientometric methods into a qualitative study. Integrative attempts of this kind are poorly supported by the methodologies of both the sociology of science and scientometrics. Therefore it was necessary to develop a project-specific methodological approach that linked scientometric methods to theoretical considerations. The methodological approach is presented and used to discuss general methodological problems concerning the relation between (qualitative) theory and scientometric methods. This discussion enables some conclusions to be drawn as to the relations that exist between scientometrics and the sociology of science. This revised version was published online in June 2006 with corrections to the Cover Date.     

An integrated approach for validating micro mechanical systems based on simulation and test

Miniaturization of macroscopic mechanical systems enables the opening of new areas of application for micro technological systems. Because of technological restrictions, especially when applying miniaturized conventional manufacturing techniques, shape and material deviations cannot be scaled down in the same dimension like micro parts. Thus, the long-term objective is to ensure the functioning by appropriate design measures. In doing so, determination of the transfer behavior by modeling and simulation is required. This work presents two ways for ensuring the required properties of micro gears and describes how the results do correlate. The experimental way uses the radial composite inspection as it is used in the macroscopic world. The simulative way deploys a rolling simulation by utilization of finite element analysis. The virtual prototypes are originated on measured real test gears. When comparing experiment and simulation of the rolling behavior, in some short and long wave areas deviations can be recognized. These can be ascribed to the reduction from three to two dimensions when modeling. Other deviations might be based on inaccuracies when mounting into the test rig. In other areas quite good correlations of test and simulation could be ascertained.