In-situ microwave-assisted catalytic upgrading of heavy oil: Experimental validation and effect of catalyst pore structure on activity.

In-situ combustion alone may not provide sufficient heating for downhole, catalytic upgrading of heavy oil in the Toe-to-Heel Air Injection (THAI) process. In this study, a new microwave heating technique has been proposed as a strategy to provide the requisite heating. Microwave technology is alone able to provide rapid heating which can be targeted at the catalyst packing and/or the incoming oil in its immediate vicinity. It was demonstrated, contrary to previous assertions, that heavy oil can be heated directly with microwaves to 425 °C, which is the temperature needed for successful catalytic upgrading, without the need for an additional microwave susceptor. Upgrading of >3.2° API points, a reduction in viscosity to less than 100 cP, and >12% reduction in sulfur content was achieved using commercially available hydrodesulfurization (HDS) catalyst. The HDS catalyst induced dehydrogenation, with nearly 20% hydrogen detected in the gas product. Hence, in THAI field settings, part of the oil-in-place could be sacrificed for dehydrogenation, with the produced hydrogen directed to aid hydrodesulfurization and improve upgrading. Further, this could provide a route for downhole hydrogen production, which can contribute to the efforts towards the hydrogen economy. A single, unified model of evolving catalyst structure was developed. The model incorporated the unusual gas sorption data, computerized x-ray tomography and electron microprobe characterization, as well as the reaction behavior. The proposed model also highlighted the significant impact of the particular catalyst fabrication process on the catalytic activity.

Characterisation of potato crisp effective porosity using micro-CT.

BACKGROUND: The effective porosity is an important quantitative parameter for food products that has a significant effect on taste and quality. It is challenging to quantify the apparent porosity of fried potato crisps as they have a thin irregularly shaped cross section containing oil and water. This study uses a novel micro-CT technique to determine the solid volume fraction and hence the effective porosity of three types of potato crisps: standard continuously fried crisps, microwaved crisps, and continuously fried 'kettle' crisps. RESULTS: It was found that continuously fried kettle crisps had the lowest effective porosity at 0.54, providing the desired crunchy taste and lower oil contents. Crisps produced using a microwave process designed to mimic the dehydration process of standard continuous fried crisps had an effective porosity of 0.65, which was very similar to the effective porosity of 0.63 for standard continuously fried crisps. The results were supported by the findings of a forced preference consumer test. CONCLUSION: The effective porosity affects the product taste and is therefore a critical parameter. This study shows that micro-CT analysis can be used to characterise the change in effective porosity of a thin irregularly shaped food product, caused by a change of cooking procedure. © 2016 Society of Chemical Industry.

Multi-granularity Parallel Computing in a Genome-Scale Molecular Evolution Application.

Previously [1], we reported a coarse-grained parallel computational approach to identifying rare molecular evolutionary events often referred to as horizontal gene transfers. Very high degrees of parallelism (up to 65x speedup on 4,096 processors) were reported, yet the overall execution time for a realistic problem size was still on the order of 12 days. With the availability of large numbers of compute clusters, as well as genomic sequence from more than 2,000 species containing as many as 35,000 genes each, and trillions of sequence nucleotides in all, we demonstrated the computational feasibility of a method to examine "clusters" of genes using phylogenetic tree similarity as a distance metric. A full serial solution to this problem requires years of CPU time, yet only makes modest IPC and memory demands; thus, it is an ideal candidate for a grid computing approach involving low-cost compute nodes. This paper now describes a multiple granularity parallelism solution that includes exploitation of multi-core shared memory nodes to address fine-grained aspects in the tree-clustering phase of our previous deployment of XenoCluster 1.0. In addition to benchmarking results that show up to 80% speedup efficiency on 8 CPU cores, we report on the biological accuracy and relevance of our results compared to a reported set of known xenologs in yeast.

Adsorbate-limited conductivity of graphene.

We present a theory of electronic transport in graphene in the presence of randomly placed adsorbates. Our analysis predicts a marked asymmetry of the conductivity about the Dirac point, as well as a negative weak-localization magnetoresistivity. In the region of strong scattering, renormalization group corrections drive the system further towards insulating behavior. These results explain key features of recent experiments, and are validated by numerical transport computations.

GENDER CONVERGENCE IN THE AMERICAN HERITAGE TIME USE STUDY (AHTUS).

We present evidence from a new comprehensive database of harmonized national time-diary data that standardizes information on almost 40 years of daily life in America. The advantages of the diary method over other ways of calculating how time is spent are reviewed, along with its ability to generate more reliable and accurate measures of productive activity than respondent estimates or other alternatives. We then discuss the various procedures used to develop these harmonized data, both to standardize reporting detail and to match with Census Bureau population characteristics. We then use these data to document historical shifts in Americans' use of time, particularly focusing on gendered change in paid and unpaid work. We explore these data to find new and more complex evidence of continuing gender convergence, not just in aggregated totals of hours worked, but also in (1) the distributions of activity through the day and the week, (2) the sorts of activities that marital partners do together, as well as (3) the processes of construction of the diary accounts themselves.

Surface acoustic-wave-induced magnetoresistance oscillations in a two-dimensional electron gas.

We study the geometrical commensurability oscillations imposed on the resistivity of 2D electrons in a perpendicular magnetic field by a propagating surface acoustic wave (SAW). We show that, for omega

A framework to contain a spatially distributed model of the degradation of solid waste in landfills.

This paper describes the concept and development of a generic spatially distributed numerical model that can contain and link sub-models of landfill processes in order to simulate solid waste degradation and gas generation in landfills. The model has been designed to simulate anaerobic degradation of solid waste saturated in leachate, and to reflect the effect on degradation of the control of both the flow and chemistry of the leachate in the pore space of the solids. The model can accommodate different profiles of waste constituents and therefore has the potential to simulate the effects of pre-treatment techniques such as shredding and inoculation. Components of the model simulate the transport of leachate and gases, and the consolidation of the solid waste. The results of some prototype calculations are presented.

ESTprep: preprocessing cDNA sequence reads.

MOTIVATION: High accuracy of data always governs the large-scale gene discovery projects. The data should not only be trustworthy but should be correctly annotated for various features it contains. Sequence errors are inherent in single-pass sequences such as ESTs obtained from automated sequencing. These errors further complicate the automated identification of EST-related sequencing. A tool is required to prepare the data prior to advanced annotation processing and submission to public databases. RESULTS: This paper describes ESTprep, a program designed to preprocess expressed sequence tag (EST) sequences. It identifies the location of features present in ESTs and allows the sequence to pass only if it meets various quality criteria. Use of ESTprep has resulted in substantial improvement in accurate EST feature identification and fidelity of results submitted to GenBank. AVAILABILITY: The program is freely available for download from http://genome.uiowa.edu/pubsoft/software.html