Enhanced techniques on sequential unit commitment with interchangetransactions

This paper presents two enhanced techniques for improving the solution optimality and computation performance of the sequential unit commitment (SC) method with interchange transactions. The conventional SC method, although often presenting superior performance over other methods, can lead to nonnear-optimal solutions in some circumstances due to the use of a local decision scheme to identify the best unit to be committed at each stage. The proposed technique, instead, uses a global-like decision scheme. It defines a small set of locally advantageous units which are individually examined globally by generating tentative commitment schedules to identify the globally best unit to commit at each stage. Studies have shown that the global-like decision scheme can effectively improve the solution optimality. Meanwhile, while an interchange transaction is incorporated with the unit commitment study, the constant transaction price often causes solution oscillation during iterations. A varying-λ technique is proposed in this paper. This technique properly models the impact of the interchange transactions on the power system hourly energy prices and, hence, successfully overcomes the oscillation problem such that the loading level of a transaction can be optimally determined similarly as for a generating unit     

Changes in organic acid composition during incubation of aseptically-grown grass

The organic acid composition of aseptically-grown timothy grass (Phleum pratense) was examined. Changes in organic acids of the grass during incubation in small test tubes with and without the addition of lactic acid bacteria were studied. Malic acid, a major acid of the grass, was broken down during incubation mainly by the activity of bacterial enzymes. The amount of succinic acid was increased by the action of both plant and bacterial enzymes. Citric acid was not detected in the aseptically-grown timothy grass but two unidentified acids formed a major part of the total organic acid fraction.     

Control of concentration during academic tasks.

Evaluated 3 strategies for controlling concentration during academic tasks. 82 undergraduates served as Ss. One strategy, self-initiated relaxation (SIR), required Ss to employ a combination of relaxation techniques to set and maintain constructive study and test-taking states. The 2nd strategy, self-coaching (SC), was an extension of the positive self-talk techniques developed by D. Meichenbaum (1972). Ss were taught to coach (talk) themselves into constructive states and to maintain these states during studying and test taking. Finally, a 3rd strategy that combined SIR and SC was created. Results indicate that the 3rd strategy, SIR plus SC, significantly facilitated some aspects of academic performance in comparison to a no-treatment control group. (18 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Combining liquid chromatography with MALDI mass spectrometry using a heated droplet interface

A novel interfacing technology is described to combine solution-based separation techniques such as liquid chromatography (LC) with matrix-assisted laser desorption ionization (MALDI) mass spectrometry. The interface includes a transfer tube having an inlet and an outlet, the inlet being adapted to accept the LC effluents and the outlet being adapted to form continuously replaced, hanging droplets of the liquid stream, and a MALDI sample plate mounted below the outlet of the transfer tube for collecting the droplets. The liquid stream in the transfer tube is heated to a temperature sufficient to cause partial evaporation of the carrier solvent from the hanging droplets. The droplets are dislodged to the MALDI plate, which is heated to above the boiling point of the carrier solvent to cause further evaporation of the carrier solvent from the collected droplets. It is found that analytes can be fractionated and deposited to a sample spot of 0.8 mm in diameter when a liquid flow rate of up to 50 microL/min and a fractionation interval of 1 min/spot are used. Flow rate of up to 200 microL/min can be used with a deposition sample spot of 2.4 mm in diameter on a commercial MALDI target. This heated droplet interface does not introduce sample loss, and the detection sensitivity of LC/MALDI is similar to that of standard MALDI, i.e., low femtomoles for peptide analysis with a microliter sample deposition. It is compatible with microbore and narrow-bore column separation, thus allowing the injection of a larger amount of sample for separation and analysis, compared to a capillary column LC/MALDI system. The detection dynamic range is shown to be in the order of 10(6) for peptide mixture analysis, which is 4 orders of magnitude greater than standard MALDI. The application of this interface for combining LC with MALDI MS/MS is demonstrated in the proteome analysis of water-soluable protein components of E. coli K12 extracts.     

Calibration measurements and standards for radiation protection dosimetry

The safe use of ionising radiation for applications in medicine, electric power production and industrial processes requires accurate measurements that are traceable to national standards. Radiological calibration laboratories provide measurements that may be used to determine the calibration coefficients for personal dosemeters and survey meters. The wide range of ionising radiation applications results in the need for a wide range of reference radiation types and intensities to be available in the calibration laboratory. The methods used and the problems encountered while developing reference radiations are discussed.     

FTMS structure elucidation of natural products: application to muraymycin antibiotics using ESI multi-CHEF SORI-CID FTMS(n), the top-down/bottom-up approach,and HPLC ESI capillary-skimmer CID FTMS

The molecular formulas for the structures and substructures of muraymycin antibiotics A1 (C52H90N14O19, MW 1214) and B1 (C49H83N11O18, MW 1113) were determined using electrospray ionization (ESI) Fourier transform mass spectrometry (FTMS). The muraymycin A1 and B1 structures were elucidated by utilizing capillary-skimmer fragmentation with up to five stages of mass spectrometry (MS5). Multi-CHEF, a multiple ion isolation method, was used at each stage of MS(n) to isolate a parent ion and up to four reference ions, for exact-mass calibration. The parent ions were fragmented by SORI-CID and the product ions internally calibrated with average absolute mass errors less than 1 ppm at each stage in the fragmentation processes. Using the top-down/bottom-up approach, the molecular formulas for the antibiotics were determined by summing the elemental formulas of the neutral losses, obtained by measuring the mass differences (<500 Da) between the genetically related sequential parent ion masses in the MS(n) spectra, with the unique elemental formula of the lowest parent ion mass (<500 Da). The structures of 12 additional compounds in the muraymycin complex were elucidated using HPLC ESI capillary-skimmer CID FTMS by correlating their fragmentation patterns with those of muraymycins A1 and B1. Sequential neutral losses of an aminosugar, a valine, a uridine, and an ester fatty acid from the muraymycin parent ions provided diagnostic fragments for characterization.     

Behavioral influences of proximal alarms

Confidence in and responses to an unreliable test alarm were studied in the presence of nearby unspecified alarms. The test alarm's reliability rate was represented as averaging "true" only 50% or 60% of the time. Confidence or response rates ranged proportionately from 23% to 97% with the number of active alarms within 5, 6, 7, or 9 annunciator arrays. Adjacent alarms resulted in confidence estimates that were higher (by about 10%) than those with the same number of active alarms spaced up to 3 positions away. Simultaneously activated alarms resulted in a more than 20% increase in "true" responses compared with the same number of alarms offset in time by up to 32 s, regardless of which came first. Active alarms "known" to be functionally related to, or independent of, the test alarm substantially raised or lowered responding but did not completely overcome prior effects. These findings indicate that presumptions that operators' responses are not influenced by nearby alarms, regardless of their function, may be unwarranted. Applications of this research include suggestions to improve responding and training recommendations.