1,347 research outputs found
An experience of introducing last planner into a UK construction project
The Last Planner methodology developed by the Lean Construction Institute is a production control tool which has possible benefits for improving planning in the UK construction industry. Its application has been considered in countries outside the UK but there is scope for considering whether it is a practical tool for use in UK construction projects. The application of the methodology to a UK construction project was studied with a view to establishing the value of the tool and the possible barriers to its implementation. After training by the writers the method was developed for use on a project by the project team and applied to the main activities. The writers observed the process and interviewed the participants. The methodology had some success in terms of improving structure and discipline in planning but there were structural and cultural barriers identified which need to be addressed before it can be fully successful
Implementing lean: UK culture and systems change
For the IGLC 12 Conference the authors reported the results of implementing Last PlannerTM methods with a large UK contracting company. The projects studied demonstrated some success but also some cultural, organizational and systemic barriers to its effective implementation. Alarcon and Conte’s White Paper for the IGLC11 conference discussed these issues and invited researchers to consider them. In response, the authors have reflected upon and critically re-analysed the research as a means to refocus their future work in implementing Lean Construction methods in UK construction. Based on a review of the literature on construction culture we have identified theoretical factors that, together with Alarcon and Conte's list of critical organizational elements, provide a framework against which the results of the research have been considered. We conclude that the implementation of Last Planner was hindered by not fully considering cultural, organizational and systemic problems and by failing to recognize how deepseated these problems could be. We intend, in future projects, to take a more considered, and wider approach to Lean Construction (possibly using the LCI’s Lean Project Delivery System) and to focus our attention upon construction ventures where efforts at culture change have already started - in particular, where strategic partnering arrangements are in place
DFT-Assisted Design and Evaluation of Bifunctional Amine/Pyridine-Oxazoline Metal Catalysts for Additions of Ketones to Unactivated Alkenes and Alkynes
Bifunctional catalyst systems for the direct addition of Âketones to unactivated alkenes/alkynes were designed and modeled by density functional theory (DFT). The designed catalysts possess bidentate ligands suitable for binding of pi-acidic group 10 metals capable of activating alkenes/alkynes, and a tethered organocatalyst amine to Âactivate the ketone via formation of a nucleophilic enamine intermediate. The structures of the designed catalysts before and after C–C bond formation were optimized using DFT, and reaction steps involving group 10 metals were predicted to be significantly exergonic. A novel oxazoline precatalyst with a tethered amine separated by a meta-substituted benzene spacer was synthesized via a 10-step sequence that Âincludes a key regioselective epoxide ring-opening step. It was combined with group 10 metal salts, including cationic Pd(II) and Pt(II), and screened for the direct addition of ketones to several alkenes and an Âinternal alkyne. 1H NMR studies suggest that catalyst-catalyst interÂactions with this system via amine–metal coordination may preclude the desired addition reactions. The catalyst design approach disclosed here, and the promising calculations obtained with square planar group 10 metals, light a path for the discovery of novel bifunctional catalysts for C–C bond formation
An Analysis of the Relationship between Fish Harvesting and Processing Sectors in New England
Using annual data from 1981 to 2002, the relationship between harvesting and processing of fish and the effects of imports on processing in New England were analyzed. Additionally, cause and effect relationships between harvesting and processing and between processing and imports were examined using Granger causality tests. Output from the fish processing sector is jointly driven by local fish landings and fish imports and unidirectional causalities exist from local landings to processing and from processing to imports. Generally, processors optimize business operations over multiple species and multiple supply sources. Rebuilding the groundfish stock would not lead to a dramatic and immediate increase in the processing industry. Instead, the actual growth in the processing sector would be relatively smaller than that in the harvesting sector.Fish processing, fish harvesting, fish imports, causality., Q2, Q22, L66, Resource /Energy Economics and Policy,
Taking the Plunge: Requiring the ETD
It made sense for Caltech, the California Institute of Technology (a private, technically focused, U.S. university, http://www.caltech.edu), to go electronic when it comes to theses. It took, however, more than three years: From March 1999 when Prof. Ed Fox of the Virginia Technical University spoke at Caltech to July 2002 when ETDs became required for all PhD candidates. How was it done and what are the lessons learned
Comparing Community Structure to Characteristics in Online Collegiate Social Networks
We study the structure of social networks of students by examining the graphs
of Facebook "friendships" at five American universities at a single point in
time. We investigate each single-institution network's community structure and
employ graphical and quantitative tools, including standardized pair-counting
methods, to measure the correlations between the network communities and a set
of self-identified user characteristics (residence, class year, major, and high
school). We review the basic properties and statistics of the pair-counting
indices employed and recall, in simplified notation, a useful analytical
formula for the z-score of the Rand coefficient. Our study illustrates how to
examine different instances of social networks constructed in similar
environments, emphasizes the array of social forces that combine to form
"communities," and leads to comparative observations about online social lives
that can be used to infer comparisons about offline social structures. In our
illustration of this methodology, we calculate the relative contributions of
different characteristics to the community structure of individual universities
and subsequently compare these relative contributions at different
universities, measuring for example the importance of common high school
affiliation to large state universities and the varying degrees of influence
common major can have on the social structure at different universities. The
heterogeneity of communities that we observe indicates that these networks
typically have multiple organizing factors rather than a single dominant one.Comment: Version 3 (17 pages, 5 multi-part figures), accepted in SIAM Revie
Highly nonlinear solitary waves in periodic dimer granular chains
We investigate the propagation of highly nonlinear solitary waves in heterogeneous, periodic granular media using experiments, numerical simulations, and theoretical analysis. We examine periodic arrangements of particles in experiments in which stiffer and heavier beads (stainless steel) are alternated with softer and lighter ones (polytetrafluoroethylene beads). We find good agreement between experiments and numerics in a model with Hertzian interactions between adjacent beads, which in turn agrees very well with a theoretical analysis of the model in the long-wavelength regime that we derive for heterogeneous environments and general bead interactions. Our analysis encompasses previously studied examples as special cases and also provides key insights into the influence of the dimer lattice on the properties (width and propagation speed) of the highly nonlinear wave solutions
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