Collaboration Environments for Construction: Implementation Case Studies

Although emerging technologies offer the construction industry many opportunities for computer supported collaboration environments, the companies adopting these technologies usually fail in achieving the full benefits from their implementations. The reason for this is found to be focusing too much on the technical factors and ignoring or underestimating the factors related to change, implementation, human and organizational factors, and the roles of the management and end users. Each new information technology (IT) implementation involves some change for the organization and the employees, and is therefore a source of resistance and confusion unless special attention is paid to managing this change. This paper aims to review the related theoretical concepts and previous work on success factors for collaboration environment implementations and failure reasons for IT, and to present the current approaches adopted by construction organizations implementing collaboration environments. In order to achieve these aims, the results of an extensive literature review on general causes of failure in IT implementations are presented, and the key areas to focus on during IT design and implementation are highlighted and explained. The results of exploratory case studies are summarized to show the current IT implementation and collaborative working approaches in the United Kingdom construction industry and interpreted using a systems thinking approach. The paper then concludes with some insights into how construction organizations can improve the implementation of collaboration systems.     

Effect of Al2O3 Additions on the Thermal Expansion Behavior of a Li2O-ZnO-SiO2 Glass-Ceramic

The effect of Al₂O₃ substitution on the thermal expansion behavior of a Li₂O-ZnO-SiO₂ glass-ceramic was investigated using differential thermal analysis, X-ray diffractometry, and dilatometry. The coefficient of thermal expansion of the original Al₂O₃-free glass-ceramic measured between 20° and 900°C decreased from 12.4 × 10^-6°C^-1 to 6.3 × 10^-6°C^-1 with Al₂O₃ substitution for ZnO up to 11 wt%. The results were correlated to the changes in the phase assemblage with Al₂O₃ addition.     

Detection of the frequency, antimicrobial susceptibility, and genotypic discrimination of Aeromonas strains isolated from municipally treated tap water samples by cultivation and AP-PCR

The frequency, antibiotic susceptibility, and genotypic discrimination of Aeromonas strains isolated from municipally treated drinking tap water distribution systems were investigated in this study. We have analyzed 148 tap water samples collected from 8 different locations by bacterial cultivation and arbitrarily primed polymerase chain reaction (AP-PCR). Gram negative, hemolytic, oxidase (+) and catalase (+) bacterial colonies were applied to the study. Identification of bacterial colonies was done by conventional biochemical method and API ID 20E panel (BioMerieux-France). Molecular epidemiological discrimination of the isolates was done by AP-PCR. Aeromonas spp. was detected in 6 of 148 (4%) tap water samples from 8 different locations. Five isolates were identified as Aeromonas hydrophila and one isolate was identified as Vibrio fluvialis by conventional biochemical method. These data were also confirmed by API 20E panel. One of 6 isolates was resistant to gentamicin, 2 of 6 isolates were resistant to trimethoprim/sulfamethoxazole, 4 of 6 isolates were resistant to ampicillin and ampicillin-sulbactam and all of 6 isolates were resistant to cephalothin. All isolates were found to be susceptible to amikacin, aztreonam, ceftazidime, ceftriaxone, ciprofloxacin. All 6 strains of Aeromonas were discriminated by AP-PCR and were determined that all isolates were from different genotypic sources. Although the frequency of the isolates was under the standard limits, the results indicate that hemolytic A. hydrophila are present in municipally treated tap water samples in Mersin City. While all strains were genotypically distinct, all of them were resistant to first generation beta lactam antibiotics tested in this study.     

Gabapentin-induced coma in a patient with renal failure

We describe a 60-year-old woman who became comatose after a single dose of gabapentin for right-sided sciatalgia. The patient was improved by hemodialysis. Gabapentin toxicity should be considered when mental status changes develop in patients with renal failure after even a single dose.     

Fluence rate distribution in laser-induced interstitial thermotherapy by mesh free collocation

The present work introduces an alternative method for calculating the spatial distribution of interstitial fluence rate in laser-induced interstitial thermotherapy. The method originates from the un-simplified integral–differential radiant transport equation, which is then solved by the radial basis function collocation technique. After comparing with the Monte Carlo and finite volume methods, it is concluded that this method is able to provide accurate predictions of fluence rate distributions along the penetration depth, particularly around the boundary.     

Analysis and performance assessment of NH3 and H2 fed SOFC with proton-conducting electrolyte

The present paper investigates the performance of a solid oxide fuel cell based on proton-conducting electrolyte (SOFC-H⁺) using one-dimensional steady-state model. The analysis covers a detailed electro-chemical model for H₂ and NH₃ fuels. The direct internal reforming of NH₃ is examined, and the effects of some operating parameters (e.g. temperature, pressure, fuel utilization and oxidant utilization) on the reversible cell potential are investigated. In addition, the overpotentials (including activation, ohmic and concentration) are calculated to study the irreversible behavior of the SOFC-H⁺ with some actual data operating conditions and material properties taken from the literature. In addition, effects of some operation and structural parameters on cell performance were examined. The present results indicate that the activation and the ohmic losses are considerable. The concentration overpotential at the anode side is negligible due to the fact that H₂O is produced at the cathode side. The maximum power density is calculated as 3212 and 3113 W/m² at 1073 K and 1 atm for the fuels of H₂ and NH₃. The results further show that H₂ provides better performance than NH₃ at the same partial pressure. Moreover, NH₃ is an excellent hydrogen carrier which is a potential candidate for SOFC-H⁺ due to its high hydrogen content and considerable cell performance.     

Some new binary quasi-cyclic codes from codes over the ring \mathbb F _2+u\mathbb F _2+v\mathbb F _2+uv\mathbb F _2

We consider quasi-cyclic codes over the ring $\mathbb{F }_2+u\mathbb{F }_2+v\mathbb{F }_2+uv\mathbb{F }_2$ , a finite non-chain ring that has been recently studied in coding theory. The Gray images of these codes are shown to be binary quasi-cyclic codes. Using this method we have obtained seventeen new binary quasi-cyclic codes that are new additions to the database of binary quasi-cyclic codes. Moreover, we also obtain a number of binary quasi-cyclic codes with the same parameters as best known binary linear codes that otherwise have more complicated constructions.     

A Review of Cooling in Microchannels

Advancements in electronic performance result in a decrease in device size and increase in power density. Because of these advancements, current cooling mechanisms for electronic devices are beginning to be ineffective. Within the localized hot spots, the materials of the components are reaching temperature values that can lead to improper functioning of the device. Many techniques have been successful in the past, such as heat sinks, cavities or grooves, micro pin-fins, etc., but still do not provide adequate cooling necessary to maintain temperature values low enough for the electronic components to operate. Microchannels, with their large heat transfer surface to volume ratio, cooled with either gas or liquid coolant, have shown some potential. By modifying the walls of the microchannel with fins, pins, or grooves, the cooling performance can be improved. A possible fin material used to increase the surface area of a microchannel is carbon nanotubes, which possess excellent thermal and mechanical properties. Numerical and computational methods needed to analyze flow at the micro- and nano-scale are also introduced. The numerical methods such as lattice Boltzmann, molecular dynamics, and computational fluid dynamics may lessen the cost and time that often accompany experimentation.