Microstructural Characterization and Role of Glassy Layer Developed on Inconel 690 During a Nuclear High-Level Waste Vitrification Process

The interaction of Inconel 690 metallic components with borosilicate melt leads to development of a partially amorphous and a partially crystalline layer within borosilicate melt adjacent to the interface. Such a heterogeneous layer is referred to here as a glassy layer. In the present investigation, the glassy layer is constituted of several phases, e.g. a Cr₂O₃ layer, a Ni₂CrO₄ needle, and NiCr₂O₄ cubic phases. Incorporation of such a glassy layer within the melt pool can lead to significant microstructural changes in the melt. Formation of barium chromate and nickel silicate has been observed in a sodium barium borosilicate melt with excess amount of Cr₂O₃ and NiO, respectively.     

3D segmentation of abdominal CT imagery with graphical models,conditional random fields and learning

Probabilistic graphical models have had a tremendous impact in machine learning and approaches based on energy function minimization via techniques such as graph cuts are now widely used in image segmentation. However, the free parameters in energy function-based segmentation techniques are often set by hand or using heuristic techniques. In this paper, we explore parameter learning in detail. We show how probabilistic graphical models can be used for segmentation problems to illustrate Markov random fields (MRFs), their discriminative counterparts conditional random fields (CRFs) as well as kernel CRFs. We discuss the relationships between energy function formulations, MRFs, CRFs, hybrids based on graphical models and their relationships to key techniques for inference and learning. We then explore a series of novel 3D graphical models and present a series of detailed experiments comparing and contrasting different approaches for the complete volumetric segmentation of multiple organs within computed tomography imagery of the abdominal region. Further, we show how these modeling techniques can be combined with state of the art image features based on histograms of oriented gradients to increase segmentation performance. We explore a wide variety of modeling choices, discuss the importance and relationships between inference and learning techniques and present experiments using different levels of user interaction. We go on to explore a novel approach to the challenging and important problem of adrenal gland segmentation. We present a 3D CRF formulation and compare with a novel 3D sparse kernel CRF approach we call a relevance vector random field. The method yields state of the art performance and avoids the need to discretize or cluster input features. We believe our work is the first to provide quantitative comparisons between traditional MRFs with edge-modulated interaction potentials and CRFs for multi-organ abdominal segmentation and the first to explore the 3D adrenal gland segmentation problem. Finally, along with this paper we provide the labeled data used for our experiments to the community.     

Dynamic pricing of call rates: Bayesian approach

In this paper, we present different cases and their possible solutions in the telecommunications market by incorporating dynamically changing call rates over the channel depending upon the network congestion. Since dynamic pricing of call rates is beneficial from both the perspectives of subscribers and service providers, our solution can significantly help to adapt this pricing mechanism in real market scenario. In order to deploy this scheme, we have incorporated the competing network provider's strategy into the mechanism of deciding dynamic price. Establishment of Nash equilibrium with the competing network provider has stabilized our pricing mechanism.     

Location and time do matter: A long tail study of website requests

There has been a tremendous growth in the amount and range of information available on the Internet. The users' requests for online information can be captured by a long tail model. A few popular websites enjoy a high number of visitations while the majority of the rest are less frequently requested. In this study we use real world data to investigate this phenomenon and show that both users' physical location and time of access affect the heterogeneity of website requests. The effect can partially be explained by differences in demographic characteristics at locations and diverse user browsing behavior in weekdays and weekends. These results can be used to design better online marketing strategies, affiliate advertising models, and Internet caching algorithms with sensitivities to user location and time of access differences.     

Seamless live migration of virtual machines over the MAN/WAN

The “VM Turntable” demonstrator at iGRID 2005 pioneered the integration of Virtual Machines (VMs) with deterministic “lightpath” network services across a MAN/WAN. The results provide for a new stage of virtualization—one for which computation is no longer localized within a data center but rather can be migrated across geographical distances, with negligible downtime, transparently to running applications and external clients. A noteworthy data point indicates that a live VM was migrated between Amsterdam, NL and San Diego, USA with just 1–2 s of application downtime. When compared to intra-LAN local migrations, downtime is only about 5–10 times greater despite 1000 times higher round-trip times.     

Sol-gel poly(ethylene glycol) stationary phase for high-resolution capillary gas chromatography

A sol-gel chemistry-based method was developed for the preparation of highly stable capillary gas chromatography (GC) columns with surface-bonded poly(ethylene glycol) (PEG) stationary phase. Through a single-step procedure, it concurrently provided column deactivation, stationary-phase coating, and chemical immobilization of the coated film. Sol-gel reactions were carried out within fused-silica capillaries that were filled with properly designed sol solutions containing two sol-gel precursors, two different triethoxysilyl-derivatized poly(ethylene glycol)s, two sol-gel catalysts, and a deactivation reagent. Hydrolytic polycondensation reactions led to the formation of a sol-gel coating chemically bonded to the inner walls of the capillary. A number of sol-gel coated fused-silica capillary columns were prepared using sol-gel-active PEG derivatives. These columns demonstrated many inherent advantages, the main being the strong anchoring of the coating to the capillary wall resulting from chemical bonding with the silanol groups on the fused-silica capillary inner surface. This chemical bonding yielded strongly immobilized PEG coatings with outstanding thermal stability (up to 320 degrees C). To our knowledge, such a high thermal stability has not been achieved so far on conventionally prepared PEG GC columns. Sol-gel PEG columns provided excellent chromatographic performances: high number of theoretical plates, excellent run-to-run and column-to-column reproducibility, and pronounced selectivity for a wide range of test solutes. Using n-octadecane as a test solute (k = 7.14), an efficiency value of 3200 theoretical plates/m was obtained on a 10 m x 0.25 mm i.d. fused-silica capillary column. Five sol-gel PEG columns provided RSD values of 1.09% for column efficiency (solute, n-octadecane), 1.37% for retention factor (solute, n-octadecane), and 0.9% for separation factor (for solute pair o- and p-xylene). In five replicate measurements using the same column, RSD values of less than 0.50% for the retention time and 1.36% for retention factor (k) were obtained.     

Detection of drugs of abuse in saliva by surface-enhanced Raman spectroscopy (SERS)

Eighty drugs of abuse and metabolites were successfully measured by surface-enhanced Raman spectroscopy (SERS) using gold- and silver-doped sol-gels immobilized in glass capillaries. A method was developed that provided consistent detection of 50 ppb cocaine in saliva in a focused study. This general method was successfully applied to the detection of a number of additional drugs in saliva, such as amphetamine, diazepam, and methadone.     

Microwave-assisted low-cost synthesis of sucrose-soya ester from vegetable oil refinery by-product and its application in toothpaste formulation for oral hygiene

The major drawbacks of the sucrose ester (SE), in spite of being a green nonionic surfactant, are the difficulty of synthesis and higher cost. Distilled soya acid oil (DSAO) obtained as by-product from a vegetable oil refinery was used for the synthesis of fatty acid methyl ester (SAFAME). Microwave-assisted method (680 watts system), which is greener and more efficient was used for the synthesis of SAFAME at 99.3% conversion using 2 wt% sulfuric acid catalyst within 30 min as well as for the synthesis of SE at 82.5% conversion using 5 wt% K₂CO₃ catalyst within 45 min. Both synthesis steps were monitored and characterized by using thin-layer chromatography, gas chromatography, ¹H NMR, and FT-IR. The surface tension of 1% aq. solution of SE was 29.58 mN m⁻¹, while the interfacial tension of n-heptane-1% aq. solution was observed to be 3.29 mN m⁻¹. The critical micelle concentration was 74.24 mg L⁻¹. Foaming properties, emulsion stability, and wetting power were determined by using standard techniques. The SE was used for the development of desensitizing anticavity toothpaste formulation and the various properties were evaluated in comparison with the commercial toothpaste formulation available in the market. The results show that the partially renewable surfactants like sodium dodecyl sulfate (SDS) and sodium lauryl ether sulfate (SLES) can be replaced partially or fully with the biobased renewable SE surfactants in the various personal care formulations including toothpaste.     

Teaching Real-World Issues through Case Studies*

Engineering students are expected to be not only technically proficient, but, also to exhibit a sound awareness of real-world issues such as marketing, finance, communications, and interpersonal relations. We found that this is best learned by participating in a case study method of instruction. This paper describes the results of a research undertaken by the authors to develop a teaching methodology to bring real-world issues into engineering classrooms. It describes the steps taken in developing an engineering-management case study, administering this case study in a classroom, and results of evaluating the effectiveness of this method of instruction. In particular, it focuses on the students' and professional engineers' perceptions on the utility of the case study method of instruction in engineering classes. The results of the research lead to recommendations to funding agencies and educators on the need to develop interdisciplinary technical case studies so that the innovations happening in the engineering world can be communicated to the students in the classrooms.     

Structured Model for Batch Culture Growth of Lactobacillus bulgaricus

Batch fermentation kinetics of Lactobacillus bulgaricus were examined in detail using the methodology of cybernetic modelling. The effect of pH and lactate ion on the activity of the enzyme β-galactosidase was simulated. Cybernetic modelling is mainly used for simulation of growth on multiple substrates. Here, it has been incorporated in a model which simulates pH effects on single-substrate batch growth. The expression of active enzyme is crucial for substrate and growth. It was seen that the effect of lactate ion on the activity of the enzyme was dependant on the system pH. A semi-empirical expression was obtained for the relative amount of active enzyme present in the organism and used to model the enzyme, biomass, substrate and lactic acid concentrations for the batch fermentation. The rate of biomass formation and product formation depended on the amount of enzyme synthesised, which in turn was dependant on the pH value of the system. The model developed simulates the effect of pH and lactate concentration on the expression and degradation of the enzyme. © 1997 SCI.