STEAM OXIDATION OF CARBON FORMED BY THERMAL DEGRADATION OF PMMA IN ALUMINA

In the processing of multilayer ceramic multichip modules (MCM's), a ceramic substrate, such as alumina, along with a polymer, such as poly(methyl methacrylate) (PMMA), solvents, plasticizers, flocculants, is thermally degraded before sintering. The thermal degradation of PMMA from the green body of oxide ceramics leaves behind some amount of residual carbon in the ceramic. Carbon concentration above 100 ppm has a deleterious effect on the physical properties such as fkxural strength, density, breakdown voltage and dcnsification behavior of the ceramic. This paper discusses the kinetics of oxidation of carbon formed by the thermal degradation of poly(methyt methacrylate) in alumina. Pellets of 5 urn and I urn size alumina were made at 6000 psig in a single step change. Kinetic runs were made in the temperature range of 673 to 993 K with steam as the oxidant at a flow rate of 9.96E-03 g/cm² sec. The organics (polymethyl methacrylate, methyl ethyl ketone, methanol) concentration was varied from 5 to 20 by weight%. The oxidation products were analyzed using a Varian 3700 gas chromatograph coupled with CDS 111 integrator, and by volumetric analysis. Carbon analysis was carried out at the IBM Fishkill center using a Leco analyzer. Kinetic rates and activation energies are evaluated.     

Extending the two‐stage information systems continuance model: incorporating UTAUT predictors and the role of context

This study presents two extensions to the two‐stage expectation‐confirmation theory of information systems (IS) continuance. First, we expand the belief set from perceived usefulness in the original IS continuance model to include three additional predictors identified in the unified theory of acceptance and use of technology, namely effort expectancy, social influence and facilitating conditions. Second, we ground the IS continuance model in the context of transactional systems that involve transmission of personal and sensitive information and include trust as a key contextual belief in the model. To test the expanded IS continuance model, we conducted a longitudinal field study of 3159 Hong Kong citizens across two electronic government (e‐government) technologies that enable citizens' access to government services. In general, the results support the expanded model that provides a rich understanding of the changes in the pre‐usage beliefs and attitudes through the emergent constructs of disconfirmation and satisfaction, ultimately influencing IS continuance intention. Finally, we discuss the theoretical and practical implications of the expanded model.     

Identifying and overcoming the challenges of implementing a project management office

With the ongoing challenge of successfully managing information technology (IT) projects, organizations are recognizing the need for greater project management discipline. For many organizations, this has meant ratcheting up project management skills, processes, and governance structures by implementing a project management office (PMO). While anecdotal evidence suggests that implementing a PMO can be quite difficult, few studies discuss the specific challenges involved, and how organizations can overcome them. To address this gap in existing knowledge, we conducted a Delphi study to (1) identify the challenges of implementing a PMO for managing IT projects, (2) rank these challenges in order of importance, (3) discover ways in which some organizations have overcome the top-ranked challenges, and (4) understand the role of PMO structure, metrics, and tools in the implementation of a PMO.We identified 34 unique challenges to implementing a PMO and refined this list to 13 challenges that our Delphi panelists considered most important. The top-three challenges were (1) rigid corporate culture and failure to manage organizational resistance to change, (2) lack of experienced project managers (PMs) and PMO leadership, and (3) lack of appropriate change management strategy. Through follow-up interviews with selected panelists, we identified a series of actions that can be taken to overcome these challenges including having a strong PMO champion, starting small and demonstrating the value of the PMO, obtaining support from opinion leaders, hiring an experienced program manager who understands the organization, bringing the most talented PMs into the PMO implementation team, adopting a flexible change management strategy, and standardizing processes prior to PMO implementation. The interviews were also used to better understand the role of PMO structure, metrics, and tools. In terms of PMO structure, we found that ‘light’ PMOs were more likely to be implemented successfully. Most organizations eschew formal metrics, instead relying on subjective indicators of PMO success. Lastly, it appears that PMO tools are difficult to implement unless a project management culture has been established.     

Stable inversion and parameter variations

As part of the process of automatically guiding an aircraft, we have been successful in using stable inversion to compute a desired bounded state trajectory and corresponding bounded control. In addition to this feedforward control, we must also construct a regulator to address modeling errors and disturbances. With respect to modeling errors we find that the stable inversion procedures used are so accurate that the regulator can assume a simple form, say a linear regulator about the desired trajectory. We show that under the appropriate assumptions, the bounded state trajectory and bounded control computed through stable inversion depend continuously on the parameters of the system. This is a consequence of a mathematical result that we prove about the continuous dependence of the “particular solution” of a time varying nonlinear system driven by a bounded input. This is distinct from the usual continuous dependence of the initial value problem for systems.     

Understanding e‐Government portal use in rural India: role of demographic and personality characteristics

Electronic government (e‐Government) is one of the most important ways to bridge the digital divide in developing countries. We develop a model of e‐Government portal use. We use various individual characteristics, namely demographics and personality, as predictors of e‐Government portal use. Specifically, our predictors were (1) gender, age, income and education; (2) the Big Five personality characteristics, i.e. extraversion, neuroticism, conscientiousness, agreeableness and openness to experience; and (3) personal innovativeness with information technology. We conducted a field study in a village in India. We collected data from over 300 heads of household. We found support for our model, with most variables being significant and explaining 40% of the variance in e‐Government portal use.     

Experimental and computational infrared imaging of bluff body stabilized laminar diffusion flames

The concept of comparing measured and computed images is extended to the mid-infrared spectrum to provide a non-intrusive technique for studying flames. Narrowband radiation intensity measurements of steady and unsteady bluff body stabilized laminar ethylene diffusion flames are acquired using an infrared camera. Computational infrared images are rendered by solving the radiative transfer equation for parallel lines-of-sight through the flame and using a narrowband radiation model with computed scalar values. Qualitative and quantitative comparisons of the measured and computed infrared images provide insights into the flame stabilization region and beyond. The unique shapes and sizes of the flames observed in the measured and computed infrared images are similar with a few exceptions which are shown to be educational. The important differences occur in the flame stabilization region suggesting improvements in thermal control of the experiment and soot formation and heat loss models.     

Pre-disaster investment decisions for strengthening a highway network

We address a pre-disaster planning problem that seeks to strengthen a highway network whose links are subject to random failures due to a disaster. Each link may be either operational or non-functional after the disaster. The link failure probabilities are assumed to be known a priori, and investment decreases the likelihood of failure. The planning problem seeks connectivity for first responders between various origin–destination (O–D) pairs and hence focuses on uncapacitated road conditions. The decision-maker's goal is to select the links to invest in under a limited budget with the objective of maximizing the post-disaster connectivity and minimizing traversal costs between the origin and destination nodes. The problem is modeled as a two-stage stochastic program in which the investment decisions in the first stage alter the survival probabilities of the corresponding links. We restructure the objective function into a monotonic non-increasing multilinear function and show that using the first order terms of this function leads to a knapsack problem whose solution is a local optimum to the original problem. Numerical experiments on real-world data related to strengthening Istanbul's urban highway system against earthquake risk illustrate the tractability of the method and provide practical insights for decision-makers.     

Preparation and study of YSTZ-Al2O3 nanocomposites

Yttria stabilized zirconia-alumina (YSTZ-Al₂O₃) nanocomposite system with various Al₂O₃ concentrations has been synthesized by sol-gel route. The experimental techniques XRD, DTA, TGA, FT-Raman, FT-IR, SEM, Vickers hardness measurements, density measurements and Impedance spectroscopy were used to characterize the synthesized specimens. DTA result shows two exothermic reactions: one around 760°C and another around 960°C. XRD results confirm that the specimen starts to crystallize on heating above 750°C. Well resolved XRD reflections corresponding to tetragonal (t) ZrO₂ were obtained after the specimens were heated at 1000°C. FT-Raman results confirmed that the crystallites developed above 750°C was t-ZrO₂. It was observed from the XRD and DTA results that the bulk and grain boundary region crystallize independently in two different temperatures with a difference in temperature of about 200°C. The crystallization temperatures increase with Al₂O₃ contents. At 1300°C, the pure YSTZ and 5 and 10 wt % Al₂O₃ added YSTZ specimens underwent structural transformation from tetragonal to monoclinic ZrO₂. But, the tetragonal symmetry remains stable at 1300°C with an addition of 15 wt % Al₂O₃. The system which retain its tetragonal symmetry at its processing temperature (1300°C) gives high hardness and maximum density values. Almost 100% theoretical density value was obtained at 1300°C with an addition of 15 wt % of Al₂O₃.     

Vapor phase oxidation of p-xylene

The kinetics of the vapor phase oxidation of p-xylene over ferric molybdate catalyst were studied in an isothermal, differential, tubular flow reactor in the temperature range of 360 to 420° C. The major product obtained was p-tolualdehyde with small amounts of maleic anhydride and p-toluic acid. No terephthalic acid or CO₂ were observed. The reaction rate data collected fit the redox model given by Equation 1. The values of activation energies E_x, E_o and frequency factors A_x, A_o obtained are 72, 63 kJ/mol and 0.64, 2.89 m³/kg catalyst s respectively. The reaction mechanism was established by studying the oxidation of p-tolualdehyde, toluic and terephthalic acids. It is concluded that the reaction follows a parallel-consecutive scheme.