Organization and governance in construction

Transaction cost analysis provides a viable theoretical perspective for the study of organization and governance in construction. The trilateral governance of a client, engineering consultant, and contractors commonly observed in industrial construction projects is detailed. The implications of a professional relationship between the client and the consultant and a clan-type relationship between the consultant and the contractors are discussed within the context of large construction projects.     

Long Frame Sync Words for Binary PSK Telemetry

Correlation criteria have previously been established for identifying whether a given binary sequence would be a good frame sync word for phase-shift keyed telemetry. In the past, the search for a goodK-bit sync word has involved the application of these criteria to the entire set of 2^KbinaryK-tuples. It is shown that restricting this search to a much smaller subset consisting ofK-bit prefixes of pseudonoise sequences results in sync words of comparable quality, with greatly reduced computer search times for larger values ofK. As an example, this procedure is used to find good sync words of length 16-63; from a storage viewpoint, each of these sequences can be generated by a 5- or 6-bit linear feedback shift register.     

Urine extravasation secondary to upper urinary tract obstruction

To the best of our knowledge, this is the first reported case of renal salvage in a neonate with presumed spontaneous perirenal leakage of urine associated with ureteropelvic junction obstruction. Many instances of such extravasation in this age group have been described with lower urinary tract obstructions. As in the latter cases, the occurrence of extravasation secondary to upper tract obstruction need not preclude primary reconstruction.     

Convoys of social support: An intergenerational analysis.

Within the Convoy Model, social networks are viewed as dynamic hierarchic structures surrounding the individual throughout life. As a step toward empirical definition of convoy structure and function across the life span, a bicultural sample (N?=?159) of young adult women, their mothers, and their grandmothers were queried. Comparable results were obtained across generations and cultures with regard to network size, the amount of support provided by the network, and the nomination of close family members as primary sources of support. However, there was a marked shift across generations in the balance of familial vs friendship relations. Younger persons included fewer family members and more friends in their networks, and they received more support from friends. These cross-sectional results are consistent with the Convoy Model and suggest that longitudinal research is warranted. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Characterizing the shape of anatomical structures with Poisson's equation

Poisson's equation, a fundamental partial differential equation in classical physics, has a number of properties that are interesting for shape analysis. In particular, the equipotential sets of the solution graph become smoother as the potential increases. We use the displacement map, the length of the streamlines formed by the gradient field of the solution, to measure the "complexity" (or smoothness) of the equipotential sets, and study its behavior as the potential increases. We believe that this function complexity = f(potential), which we call the shape characteristic, is a very natural way to express shape. Robust algorithms are presented to compute the solution to Poisson's equation, the displacement map, and the shape characteristic. We first illustrate our technique on two-dimensional synthetic examples and natural silhouettes. We then perform two shape analysis studies on three-dimensional neuroanatomical data extracted from magnetic resonance (MR) images of the brain. In the first study, we investigate changes in the caudate nucleus in Schizotypal Personality Disorder (SPD) and confirm previously published results on this structure. In the second study, we present a data set of caudate nuclei of premature infants with asymmetric white matter injury. Our method shows structural shape differences that volumetric measurements were unable to detect.     

MXene Composite and Coaxial Fibers with High Stretchability and Conductivity for Wearable Strain Sensing Textiles

The integration of nanomaterials with high conductivity into stretchable polymer fibers can achieve novel functionalities such as sensing physical deformations. With a metallic conductivity that exceeds other solution‐processed nanomaterials, 2D titanium carbide MXene is an attractive material to produce conducting and stretchable fibers. Here, a scalable wet‐spinning technique is used to produce Ti₃C₂T_x MXene/polyurethane (PU) composite fibers that show both conductivity and high stretchability. The conductivity at a very low percolation threshold of ≈1 wt% is demonstrated, which is lower than the previously reported values for MXene‐based polymer composites. When used as a strain sensor, the MXene/PU composite fibers show a high gauge factor of ≈12900 (≈238 at 50% strain) and a large sensing strain of ≈152%. The cyclic strain sensing performance is further improved by producing fibers with MXene/PU sheath and pure PU core using a coaxial wet‐spinning process. Using a commercial‐scale knitting machine, MXene/PU fibers are knitted into a one‐piece elbow sleeve, which can track various movements of the wearer's elbow. This study establishes fundamental insights into the behavior of MXene in elastomeric composites and presents strategies to achieve MXene‐based fibers and textiles with strain sensing properties suitable for applications in health, sports, and entertainment.     

Object–Oriented Enterprise Modeling and Simulation of AEC Projects

In this paper we describe an object–oriented framework for developing enterprise models of Architecture, Engineering, Construction projects, and a methodology for formalizing these models such that they can be used for discrete event simulation of information processing and coordination in project execution. The simulation results can be used to predict the probable effects of carrying out proposed changes in planning and managing projects.
In our enterprise modeling framework we represent engineering design projects in terms of deliverables (requirements and solutions), plans (activities and process relations), and organization (participants and organizational relations). The resulting project model is the starting point for identifying coordination requirements between project team participants. Our methodology uses matrix techniques derived from qualtiy function deployment (QFD) to identify interactions between project requirements and solutions and calculate measures of product complexity . We then describe information flow between project activities in a similar matrix and calculate measures of process uncertainty . Finally, we identify the responsibilities of project team members and use a matrix to point out organizational interdependencies .
We apply our framework and methodology to model and simulate engineering design for a major extension of an electrical power substation. Our simulation results demonstrate how project performance is contingent on the fit between the project policies and the objectives and preferences of the project team.     

Heterogeneous reactions of methylglyoxal in acidic media: implications for secondary organic aerosol formation

Recent environmental chamber studies have suggested that acid-catalyzed particle-phase reactions of organic carbonyls contribute to the formation of secondary organic aerosol (SOA). We report the first measurements of uptake of methylglyoxal on liquid H2SO4 over the temperature range of 250-298 K and acidic range of 55-85 wt %. From the time-dependent uptake the effective Henry's law solubility constant (H*) was determined. Heterogeneous reactions of methylglyoxal are shown to decrease with acidity and involve negligible formation of sulfate esters. Hydration and polymerization likely explain the measured uptake of methylglyoxal on H2SO4 and the measurements do not support an acid-catalyzed uptake of methylglyoxal. The results imply that heterogeneous reactions of methylglyoxal contribute to organic aerosol formation in less acidic media and hydration and polymerization of methylglyoxal in the atmospheric aerosol-phase are dependent on the hygroscopicity, rather than the acidity of the aerosols.