Determination of inorganic improvised explosive device signatures using laser electrospray mass spectrometry detection with offline classification

The mass spectral detection of low vapor pressure, inorganic-based explosive signatures including ammonium nitrate, chlorate, perchlorate, sugar, and the constituents contained within black powder are reported using laser electrospray mass spectrometry. The ambient pressure mass spectrometry technique combining nonresonant, femtosecond laser vaporization with electrospray postionization revealed primary and secondary signatures for trace quantities of inorganic explosives. A mixture of complexation agents in the electrospray solvent enabled the simultaneous detection of vaporized cations, anions, and neutrals in a single measurement. An offline classifier discriminated the inorganic-based explosives based on the mass spectral signatures resulting in high fidelity identification.     

Is biodegradability a desirable attribute for discarded solid waste? Perspectives from a national landfill greenhouse gas inventory model

There is increasing interest in the use of biodegradable materials because they are believed to be "greener". In a landfill, these materials degrade anaerobically to form methane and carbon dioxide. The fraction of the methane that is collected can be utilized as an energy source and the fraction of the biogenic carbon that does not decompose is stored in the landfill. A landfill life-cycle model was developed to represent the behavior of MSW components and new materials disposed in a landfill representative of the U.S. average with respect to gas collection and utilization over a range of environmental conditions (i.e., arid, moderate wet, and bioreactor). The behavior of materials that biodegrade at relatively fast (food waste), medium (biodegradable polymer) and slow (newsprint and office paper) rates was studied. Poly(3-hydroxybutyrate-co-3-hydroxyoctanoate) (PHBO) was selected as illustrative for an emerging biodegradable polymer. Global warming potentials (GWP) of 26, 720, -1000, 990, and 1300 kg CO(2)e wet Mg(-1) were estimated for MSW, food waste, newsprint, office paper, and PHBO, respectively in a national average landfill. In a state-of-the-art landfill with gas collection and electricity generation, GWP's of -250, 330, -1400, -96, and -420 kg CO(2)e wet Mg(-1) were estimated for MSW, food waste, newsprint, office paper and PHBO, respectively. Additional simulations showed that for a hypothetical material, a slower biodegradation rate and a lower extent of biodegradation improve the environmental performance of a material in a landfill representative of national average conditions.     

Mass analysis of biological macromolecules at atmospheric pressure using nonresonant femtosecond laser vaporization and electrospray ionization

A nonresonant femtosecond laser pulse, with an intensity of 10(13) Wcm(-2), vaporizes proteins and biomolecules intact, regardless of molecular structure, size or electronic structure for subsequent electrospray ionization and transfer into a mass spectrometer. Rapid, direct analysis from dried sample, aqueous solution and cellular material is demonstrated at atmospheric pressure using laser electrospray mass spectrometry (LEMS). Measurements are presented for lysozyme (14.3 kDa), hemoglobin from human blood, ovalbumin (45 kDa) from hen egg white and phospholipids from hen egg yolk. Mass analysis of biological material is performed without dilution, extraction or sample preparation, other than placing the biological material onto the sample plate.     

On generating distributed intelligence systems architectures usinggenetic algorithms

A methodology for generating large scale distributed intelligence systems (DIS's) using genetic algorithms is presented. An organizational structure (chromosome) is characterized by generic interactions (genes) among the individual nodes comprising it. The objective function evaluates each structure in the generated population against a set of structural constraints and some user defined criteria. The structures satisfying these constraints are feasible solutions to the design problem     

Optimal stochastic enforcement of parking regulations

Effective enforcement of no parking regulations, an essential operation in urban areas, is labor intensive and thus costly. Efficient, implementable enforcement strategies that can raise and keep compliance at a desired high level are needed. It is the objective of this work to determine such strategies. First a model relating enforcement (input) to compliance (output) was obtained on the basis of experimental data; its form is that of a homogeneous bilinear Markov process. Then several optimization problems that reflect different operating conditions were formulated and the corresponding enforcement strategies were derived via dynamic programming. Finally, simulations were used to analyze the practical implications of the results.     

Nonresonant femtosecond laser vaporization with electrospray postionization for ex vivo plant tissue typing using compressive linear classification

Laser electrospray mass spectrometry (LEMS) with offline classification is used to discriminate plant tissues at atmospheric pressure using an intense (10(13) W cm(-2)), nonresonant (800 nm) femtosecond laser pulse to vaporize cellular content for subsequent mass analysis. The tissue content of the plant within the 0.05 mm(2) laser interaction region is vaporized into the electrospray plume where the molecules are ionized prior to transfer into the mass spectrometer. The measurements for a flower petal, leaf, and stem of an impatiens plant reveal mass spectral signatures that enable discrimination as performed using a compressive linear classifier. The statistical analysis of the plant tissue samples reveals reproducibility of the data for replicate tissue samples and within a single tissue sample. A similar degree of discrimination was achieved for the green and white regions of aphelandra squarrosa (zebra plant) leaves.     

Active demand management for substitute products through price optimisation

This paper presents a systematic mathematical programming approach for active demand management in process industries. The proposed methodology aims to determine optimal pricing policies as well as output levels for substitute products, while taking into consideration manufacturing costs, resource availability, customer demand elasticity, outsourcing and market competition. First, profit maximisation analytical formulae are derived for determining Nash equilibrium in prices for a duopolistic market environment where each company produces only one product. An iterative algorithm is then proposed so as to determine the decision-making process by solving a series of non-linear mathematical programming (NLP) models before determining the Nash equilibrium in prices for the competing companies. The proposed algorithm is extended in order to accommodate the case of multi-product companies, each one selling a set of substitute products at different prices. The applicability of the proposed methodology is demonstrated by a number of illustrative examples.     

Composition and biosynthesis of the major hexose containing sphingolipids of pig leucocytes

The oligohexosyl ceramides of two preparations of blood leucocytes taken from large white pigs, weighing 80 kg were analyzed and found to comprise as major constituents trihexosyl ceramide, with glucose-galactose in a molar ratio of 1∶2, and glucosyl ceramide. The mean value of the two preparations was 4.9% and 1.35% of the total lipids, respectively, for the two glycolipids. Lactosyl ceramide is the major component of human leucocytes, in contrast to the pig leucocytes where it was detected in minor quantities. U-¹⁴C-glucose, incubated with bone marrow cells of young pigs (20 kg living weight), was mainly incorporated into the carbohydrate moiety of glucosyl ceramide and trihexosyl ceramide. Further analysis of this compound indicated that all three hexoses were labeled with¹⁴C and that the glucose attached to the ceramide had the highest specific activity. Time studies showed a decline in the incorporation of¹⁴C into glucosyl ceramide as compared to its incorporation into trihexosyl ceramide.