The GOODSTEP project: General Object-Oriented Database for Software Engineering Processes

The goal of the GOODSTEP project is to enhance and improve the functionality of a fully object-oriented database management system to yield a platform suited for applications such as software development environments (SDEs). The baseline of the project is the O2 database management system (DBMS). The O2 DBMS already includes many of the features regulated by SDEs. The project has identified enhancements to O2 in order to make it a real software engineering DBMS. These enhancements are essentially upgrades of the existing O2 functionality, and hence require relatively easy extensions to the O2 system. They have been developed in the early stages of the project and are now exploited and validated by a number of software engineering tools built on top of the enhanced O2 DBMS. To ease tool construction, the GOODSTEP platform encompasses tool generation capabilities which allow for generation of integrated graphical and textual tools from high-level specifications. In addition, the GOODSTEP platform provides a software process toolset which enables modeling, analysis and enaction of software processes and is also built on top of the extended O2 database. The GOODSTEP platform is to be validated using two CASE studies carried out to develop an airline application and a business application

Comparing conventional and improved organic vegetable rotations, yields and nitrogen husbandry

During 2005 to 2009 three approaches to organic vegetable rotations were compared to a conventional rotation in an interdisciplinary project. The organic rotations differed in their reliance on animal manure vs. cover crops and intercrops, but the rotation of main vegetable and cereal crops were identical in the four rotations. One organic rotation (O1) relied on import of manure for supply of nutrients, in another (O2) cover crops were used to replace most of the manure import, and in (O3) also intercrops were grown to improve natural pest regulation. The yearly import of nitrogen were on average 149, 94, 28, and 28 kg N.ha-1 in C, O1, O2, and O3 respectively. On average the yield in the O1 system was 83% of the yield in the conventional system. In the O2 rotation the yield was the same, though the nutrient import was much lower, whereas the intercrops in O3 reduced the yield to 70% of the conventional fotation. The effect on single crops varied with organic yields ranging from 60% (onion) to almost 100% (carrots, oats) of conventional yields. Crop root growth varied strongly among crops with rooting depths of less than 0.4 m (onions) to more than 2 m (cabbage, rye, fodder radish catch crop). Root growth was unaffected by cropping system, but the inclusion of deep rooted catch crops and green manures in O2 and O3 increased the total root exploitation of the soil strongly. Thus, while the O1 and O2 systems had almost identical yields and N uptake there were large differences in their effects on soil N; e.g. the subsoil (1-2.5 m) N content was on average 18 kg N.ha-1 in the O2 compared 61 and 53 kg N.ha-1 in the C and O1 respectively, indicating strongly reduced N leaching losses in O2

Thermal analysis, optimization and design of a Martian oxygen production plant

The objective is to optimally design the thermal components of a system that uses carbon dioxide (CO2) from the Martian atmosphere to produce oxygen (O2) for spacecraft propulsion and/or life-support. Carbon dioxide is thermally decomposed into carbon monoxide (CO) and O2 followed by the electrochemical separation of O2. The design of the overall system and its various individual components depends on, among other things, the fraction of the stoichiometric yield of O2 that can be realized in the system and the temperature of operation of the electrochemical separation membrane. The analysis indicates that a substantial reduction could be obtained in the mass and power requirements of the system if the unreacted CO2 were to be recycled. The concepts of an optimum temperature of the zirconia cell and impracticality of plant operation at low cell efficiencies are also discussed. The design of the thermal equipment is such that the mass and power requirements of the individual components and of the overall system are optimized

Methodology and calibration for continuous measurements of biogeochemical trace gas and O2 concentrations from a 300-m tall tower in central Siberia

We present an integrated system for measuring atmospheric concentrations of CO2, O2, CH4, CO, and N2O in central Siberia. Our project aims to demonstrate the feasibility of establishing long-term, continuous, high precision atmospheric measurements to elucidate greenhouse gas processes from a very remote, mid-continental boreal environment. Air is sampled from five heights on a custom-built 300-m tower. Common features to all species' measurements include air intakes, an air drying system, flushing procedures, and data processing methods. Calibration standards are shared among all five measured species by extending and optimising a proven methodology for long-term O2 calibration. Our system achieves the precision and accuracy requirements specified by the European Union's "CarboEurope" and "ICOS" (Integrated Carbon Observing System) programmes in the case of CO2, O2, and CH4, while CO and N2O require some further improvements. It was found that it is not possible to achieve these high precision measurements without skilled technical assistance on-site, primarily because of 2–3 month delays in access to data and diagnostic information. We present results on the stability of reference standards in high pressure cylinders. It was also found that some previous methods do not mitigate fractionation of O2 in a sample airstream to a satisfactory level

Water formation at low temperatures by surface O2 hydrogenation I: characterization of ice penetration

Water is the main component of interstellar ice mantles, is abundant in the solar system and is a crucial ingredient for life. The formation of this molecule in the interstellar medium cannot be explained by gas-phase chemistry only and its surface hydrogenation formation routes at low temperatures (O, O2, O3 channels) are still unclear and most likely incomplete. In a previous paper we discussed an unexpected zeroth-order H2O production behavior in O2 ice hydrogenation experiments compared to the first-order H2CO and CH3OH production behavior found in former studies on hydrogenation of CO ice. In this paper we experimentally investigate in detail how the structure of O2 ice leads to this rare behavior in reaction order and production yield. In our experiments H atoms are added to a thick O2 ice under fully controlled conditions, while the changes are followed by means of reflection absorption infrared spectroscopy (RAIRS). The H-atom penetration mechanism is systematically studied by varying the temperature, thickness and structure of the O2 ice. We conclude that the competition between reaction and diffusion of the H atoms into the O2 ice explains the unexpected H2O and H2O2 formation behavior. In addition, we show that the proposed O2 hydrogenation scheme is incomplete, suggesting that additional surface reactions should be considered. Indeed, the detection of newly formed O3 in the ice upon H-atom exposure proves that the O2 channel is not an isolated route. Furthermore, the addition of H2 molecules is found not to have a measurable effect on the O2 reaction channel.Comment: 1 page, 1 figur

New insights into the effects of several environmental parameters on the relative fitness of a numerically dominant class of evolved niche specialist

Adaptive radiation in bacteria has been investigated using Wrinkly Spreaders (WS), a morphotype which colonises the air-liquid (A-L) interface of static microcosms by biofilm formation with a significant fitness advantage over competitors growing lower down in the O2-limited liquid column. Here, we investigate several environmental parameters which impact the ecological opportunity that the Wrinkly Spreaders exploit in this model system. Manipulation of surface area/volume ratios suggests that the size of the WS niche was not as important as the ability to dominate the A-L interface and restrict competitor growth. The value of this niche to the Wrinkly Spreaders, as determined by competitive fitness assays, was found to increase as O2 flux to the A-L interface was reduced, confirming that competition for O2 was the main driver of WS fitness. The effect of O2 on fitness was also found to be dependent on the availability of nutrients, reflecting the need to take up both for optimal growth. Finally, the meniscus trap, a high-O2 region formed by the interaction of the A-L interface with the vial walls, was also important for fitness during the early stages of biofilm formation. These findings reveal the complexity of this seemingly simple model system and illustrate how changes in environmental physicality alter ecological opportunity and the fitness of the adaptive morphotype

Kinetics and mechanism of the formation of water cluster ions from O2(plus) and H2O in He, Ar, N2, and O2 at 296 K

The reaction sequence leading from O2(+) to H3O(+)-H2O was examined in He, Ar, N2 and O2 carrier gases in a flowing afterglow system. The rate constants for the reactions were measured and the kinetic analysis for their determination is presented. For M = N2, two new steps involving the formation and reaction of O2(+)-N2 were proposed and examined. The rate constants are discussed and compared with other experimental values

Oxygen electrode bifunctional electrocatalyst NiCo2O4 spinel

A significant increase in energy density may be possible if a two-unit alkaline regenerative H2-O2 fuel cell is replaced with a single-unit system that uses passive means for H2O transfer and thermal control. For this single-unit system, new electrocatalysts for the O2 electrode will be required which are not only bifunctionally active but also chemically and electrochemically stable between the voltage range of about 0.7 and 1.5 V. NiCo2O4 spinel is reported to have certain characteristics that make it useful for a study of electrode fabrication techniques. High surface area NiCo2O4 powder was fabricated into unsupported, bifunctional, PTFE-bonded, porous gas fuel cell electrodes by commercial sources using varying PTFE contents and sintering temperatures. The object of this study is to measure the bifunctional activities of these electrodes and to observe what performance differences might result from different commercial electrode fabricators. O2 evolution and O2 reduction data were obtained at 80 C (31 percent KOH). An irreversible reaction (i.e., aging) occurred during O2 evolution at potentials greater than about 1.5 V. Anodic Tafel slopes of 0.06 and 0.12 V/decade were obtained for the aged electrodes. Within the range of 15 to 25 percent, the PTFE content was not a critical parameter for optimizing the electrode for O2 evolution activity. Sintering temperatures between 300 and 340 C may be adequate but heating at 275 C may not be sufficient to properly sinter the PTFE-NiCo2O4 mixture. Electrode disintegration was observed during O2 reduction. Transport of O2 to the NiCo2O4 surface became prohibitive at greater than about -0.02 A/sq cm. Cathodic Tafel slopes of -0.6 and -0.12 V/decade were assumed for the O2 reduction process. A PTFE content of 25 percent (or greater) appears to be preferable for sintering the PTFE-NiCo2O4 mixture

Heavy elements in Galactic and Magellanic Cloud HII regions: recombination-line versus forbidden-line abundances

We have obtained deep optical, long-slit spectrophotometry of the Galactic HII regions M 17, NGC 3576 and of the Magellanic Cloud HII regions 30 Doradus, LMC N11B and SMC N66, recording the optical recombination lines (ORLs) of CII, NII and OII. Temperature-insensitive ORL C2+/O2+ and N2+/O2 ratios are obtained for all nebulae except SMC N66. The ORL C2+/O2+ ratios show remarkable agreement within each galactic system, while also being in agreement with the corresponding CEL ratios. For all five nebulae, the O2+/H+ abundance derived from multiple OII ORLs is found to be higher than the corresponding value derived from the strong [OIII] 4959, 5007A CELs, by factors of 1.8--2.7 for four of the nebulae. The LMC N11B nebula exhibits a more extreme discrepancy factor for the O2+ ion, ~5. Thus these HII regions exhibit ORL/CEL abundance discrepancy factors that are similar to those previously encountered amongst planetary nebulae. Our optical CEL O2+/H+ abundances agree to within 20-30 per cent with published O2+/H+ abundances that were obtained from observations of infrared fine-structure lines. Since the low excitation energies of the latter make them insensitive to variations about typical nebular temperatures, fluctuations in temperature are ruled out as the cause of the observed ORL/CEL O2+ abundance discrepancies. We present evidence that the observed OII ORLs from these HII regions originate from gas of very similar density (<3500 cm-3) to that emitting the observed heavy-element optical and infrared CELs, ruling out models that employ high-density ionized inclusions in order to explain the abundance discrepancy. We consider a scenario whereby much of the heavy-element ORL emission originates from cold (<=500 K) metal-rich ionized regions.Comment: 24 pages; 9 figures; accepted by Monthly Notices of the Royal Astronomical Societ