Implications of space and time for distributed work: an interpretive study of US–Norwegian systems development teams

In this paper, utilizing the often taken-for-granted notions of space and time, we develop an understanding of how collaboration is possible among virtual team-members spread across the globe. We do so by interpretively examining the actual experiences and work practices of virtual team-members located in the US & Norway, engaged in information systems development (ISD) projects. We identify a number of collaboration inhibitors, along with strategies used by team-members to address the challenges posed by the mismatch in time zones and the lack of physical proximity.     

A review of different perspectives on uncertainty and risk and an alternative modeling paradigm

The literature in economics, finance, operations research, engineering and in general mathematics is first reviewed on the subject of defining uncertainty and risk. The review goes back to 1901. Different perspectives on uncertainty and risk are examined and a new paradigm to model uncertainty and risk is proposed using relevant ideas from this study. This new paradigm is used to represent, aggregate and propagate uncertainty and interpret the resulting variability in a challenge problem developed by Oberkampf et al. [2004, Challenge problems: uncertainty in system response given uncertain parameters. Reliab Eng Syst Safety 2004; 85(1): 11-9]. The challenge problem is further extended into a decision problem that is treated within a multicriteria decision making framework to illustrate how the new paradigm yields optimal decisions under uncertainty. The accompanying risk is defined as the probability of an unsatisfactory system response quantified by a random function of the uncertainty.     

请不要留下您的碳足迹

尽管各国正在不断为应对全球变暖作出协同努力,但在哥本哈根召开的联合国气候变化会议已清楚地告诉我们,要达成关于二氧化碳减排的一致协议,我们仍还有大量的工作要做。     

A new smart coating of polyaniline–SiO2 composite for protection of mild steel against corrosion in strong acidic medium

Organic coating approaches for corrosion protection with inherently conducting polymers have become important because of restriction on the use of heavy metals and chromates in coatings due to their environmental problems. The present work is directed towards the synthesis of polyaniline (PANI) and polyaniline–SiO₂ composites (PSCs) by chemical oxidation polymerization in the presence of phosphoric acid and evaluation of synthesized PANI and PSCs for protection of mild steel from corrosion in a strong aggressive medium (i.e. 1.0 mol L^–1 HCl). A suitable coating with PSC was formed on mild steel using epoxy resin by the powder coating technique. A comparative study of the corrosion protection efficiency of mild steel coated with PANI and PSC in 1.0 mol L^–1 HCl solution was evaluated using the Tafel extrapolation, chrono‐amperometry and weight loss methods. The PSC coating showed that a significant reduction in the corrosion current density reflects the better protection of mild steel in an acidic environment. Higher protection efficiency up to 99% was achieved by using PSC‐coated mild steel at 6.0 wt% loading of PSC in epoxy resin. The coating performance and corrosion rate of mild steel were investigated by using immersion of polymer‐coated mild steel in 1.0 mol L^–1 HCl for 60 days and indicated that PSC‐coated mild steel showed better performance from corrosion than PANI in an acidic medium.© 2012 Society of Chemical Industry     

Investigating the structure of non-graphitising carbons using electron energy loss spectroscopy in the transmission electron microscope

We have investigated the structure and bonding in phenolic resin-based carbons as a function of heat treatment using a combination of high resolution transmission electron microscopy, electron energy loss spectroscopy, X-ray diffraction, gas adsorption and density measurements. On heat treatment, the initially amorphous material transforms to a micro-porous material containing small graphitic packets enclosing elongated pores, with a relatively small change in density but an appreciable change in planar carbon sp²-content as well as the development of significant curvature in the graphitic layers. The results from the different characterisation techniques are discussed and wherever possible, cross-correlated. They are also compared with proposed models for the microstructural development in non-graphitising carbons and also with the corresponding data obtained from graphitisable carbons. Overall the data provides strong evidence for a fullerene-based model for the microstructural development in non-graphitising carbons and more generally, the interpretation of the current EELS data has important implications for the spatially localised analysis of poorly crystalline carbon materials.     

Conductivity hysteresis in polymer electrolytes incorporating poly(tetrahydrofuran)

Conductivity hysteresis and room temperature ionic conductivities >10⁻³ S/cm were recently reported for electrolytes prepared from blends of an amphiphilic comb copolymer, poly[2,5,8,11,14-pentaoxapentadecamethylene (5-hexadecyloxy-1,3-phenylene)] (polymer I), and a linear multiblock copolymer, poly(oligotetrahydrofuran-co-dodecamethylene) (polymer II), following thermal treatment [F. Chia, Y. Zheng, J. Liu, N. Reeves, G. Ungar, P.V. Wright, Electrochim. Acta 43 (2003) 1939]. To investigate the origin of these effects, polymers I and II were synthesized in this work, and the conductivity and thermal properties of the individual polymers were investigated. AC impedance measurements were conducted on I and II doped with LiBF₄ or LiClO₄ during gradual heating to 110 °C and slow cooling to room temperature. Significant conductivity hysteresis was seen for polymer II, and was similarly observed for poly(tetrahydrofuran) (PTHF) homopolymer at equivalent doping levels. From thermogravimetic analysis (TGA), gel permeation chromatography (GPC) and ¹H NMR spectroscopy, both polymer II and PTHF were found to partially decompose to THF during heat treatment, resulting in a self-plasticizing effect on conductivity.     

A dynamic model for the interaction between a solid particle and an advancing solid/liquid interface

Most models that describe the interaction of an insoluble particle with an advancing solid-liquid interface are based on the assumption of steady state. However, as demonstrated by experimental work, the process does not reach steady state until the particle is pushed for a while by the interface. In this work, a dynamic mathematical model was developed. The dynamic model demonstrates that this interaction is essentially non-steady state and that steady state eventually occurs only when solidification is conducted at subcritical velocities. The model was tested for three systems: aluminum-zirconia particles, succinonitrile-polystyrene particles, and biphenyl-glass particles. The calculated values for critical velocity of the pushing/engulfment transition were in the same range with the experimental ones.     

HOW TO HELP INTELLIGENT SYSTEMS WITH DIFFERENT UNCERTAINTY REPRESENTATIONS COOPERATE WITH EACH OTHER

In order to solve a complicated problem one must use the knowledge from different domains. Therefore, if we want to automatize the solution of these problems, we have to help the knowledge-based systems that correspond to these domains cooperate, that is. communicate facts and conclusions to each other in the process of decision making. One of the main obstacles to such cooperation is the fact that different intelligent systems use differenl methods of knowledge acquisition and different methods and formalisms for uncertainty representation. So we need an interface f, “translating” the values x, y, which represent uncertainly of the experts’ knowledge in one system, into the values f(x), f(y) appropriate for another one.

In the present report we formulate the problem of designing such an interface as a mathematical problem, and solve it. We show that the interface must be fractionally linear: f(x) = (ax + b)/(cx + d).