This study considers the optimization of operations for an integrated fossil-renewable energy system with CO₂ capture. The system treated consists of a coal-fired power station, a temperature-swing ...absorption CO₂ capture facility powered by a natural gas combustion turbine, and wind generation. System components are represented in a modular fashion using energy and mass balances. Optimization is applied to determine hourly system dispatch to maximize operating profit given energy prices and wind generation data. A CO₂ emission constraint, modeled after a California law, is enforced. Idealized and realistic scenarios are considered, along with several different system specifications. For a year of operation, simulated using available wind and energy price data, operating profit for optimized operation is shown to be approximately 20% greater than profit using a heuristic procedure. The benefit from optimization is positively correlated with electricity price variability and mean wind generation. The impact of different component specifications and different CO₂ absorption solvents on the optimal operation of the energy system is also assessed. In total, this study demonstrates that the effective operating cost of an integrated energy system operating under a CO₂ emission constraint can be substantially reduced via optimal flexible operation.
Recently, the permanent magnet-assisted synchronous reluctance motor (PMa-SynRM) that can replace induction motor has been more studying because of the needs of the high efficiency motor development ...for minimum energy performance standard. PMa-SynRM requires the speed and position information of rotor to control motor correctly. However, sensor for rotor information has many problems such as mounting space shortage and the additional system cost. Therefore, in this paper, the speed-sensorless control based on reference model adaptive control is introduced to eliminate the sensor. And mechanical design is improved for control. The proposed method is verified by simulation.
In this paper the role of validity and reliability in the development of physical employment standards (PESs) and the consideration of these factors in determining the final pass/fail criteria for a ...PES and ultimately the legal defensibility of a PES is examined. Particular attention is paid to the use of subject-matter experts, the levels of evidence used in the establishment of the minimum acceptable pace/intensity for the completion of critical tasks, and the considerations needed in physical test selection.
Celotno besedilo
Dostopno za:
DOBA, FSPLJ, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
We sampled vegetation communities across plant invasion gradients at multiple wetland and stream mitigation sites in the Coastal Plain and Piedmont physiographic provinces of Virginia, USA. Impacts ...of invasion were evaluated by tracking changes in species composition and native vegetation community properties along the abundance gradients of multiple plant invaders. We found that native species richness, diversity, and floristic quality were consistently highest at moderate levels of invasion (ca. 5-10% relative abundance of invader), regardless of the identity of the invasive species or the type of mitigation (wetland or stream). Likewise, native species composition was similar between uninvaded and moderately invaded areas, and only diminished when invaders were present at higher abundance values. Currently, low thresholds for invasive species performance standards (e.g., below 5% relative abundance of invader) compel mitigation managers to use non-selective control methods such as herbicides to reduce invasive plant cover. Our results suggest that this could cause indiscriminate mortality of desirable native species at much higher levels of richness, diversity, and floristic quality than previously thought. From our data, we recommend an invasive species performance standard of 10% relative invader(s) abundance on wetland and stream mitigation sites, in combination with vigilant invasive plant mapping strategies. Based on our results, this slightly higher standard would strike a balance between proactive management and unnecessary loss of plant community functions at the hands of compulsory invasive species management.
The Ottawa Paramedic Physical Ability Test (OPPAT) is a physical employment standard (PES) that candidates must pass as a pre-hire requirement and that incumbents may have to pass prior to returning ...to work after absence, to demonstrate their physical capabilities as required to safely meet the demands of paramedic work. Consistent with best practice guidelines for PES development, it is important to establish reliability and to investigate sex-based performance differences. Active duty paramedics completed the OPPAT twice while candidates completed the OPPAT six times. Across all participants, a median improvement of 76.0 s was observed in OPPAT performance (922.0-846.0 s) between trial 1 and trial 2. Among candidates, OPPAT performance stabilised by the fourth trial confirming reliability. Sex-based analyses revealed median differences in OPPAT performance time of 39.0 and 63.0 s between males and females during the first and second trials respectively.
Practitioner summary: Active duty paramedics and candidates performed the Ottawa Paramedic Physical Ability Test (OPPAT) faster following familiarisation. Among candidates, performance time stabilised by the fourth trial. Performance time was slower among females, but this had less impact on females' ability to meet the OPPAT standard.
Ecolabels are designed to help consumers identify environmentally superior products and services; however, they are not all created equal. Some ecolabels have strong rules that promote environmental ...improvements, while others have weaker rules that permit free‐riding. Because information about ecolabel design and rule strength is typically not readily available at the point of purchase, consumers struggle to differentiate stronger ecolabels from weaker ones. We investigate whether ecolabel sponsorship is a signal that can help consumers distinguish between ecolabels according to the quality of their institutional design. Using data of 189 prominent ecolabels, we find that while most ecolabels have basic rules for environmental performance, monitoring, and conformance, the strength of these rules varies across labels according to sponsoring organization. Independent sponsors have the strongest ecolabel rules, followed by governments. Industry sponsored ecolabels have the weakest rule structures. Taken as a whole, these findings suggest that sponsorship may provide important information about whether an ecolabel is designed with rules that effectively condition firms to promote meaningful environmental improvements.
The US Government embarked on a modernization effort for GPS starting in the late 1990s. As a result, 8 additional signals were defined - along with numerous other capabilities - and acquisitions ...were initiated to implement the modernized signals and capabilities, in the form of the IIR-M, IIF and GPS III satellite blocks and upgrades to the ground segment. Modernized GPS is currently being deployed and used worldwide, and the performance of the system continues to improve to remain the gold standard for GNSS. The paper describes how GPS is currently being modernized and quantifies the impact of this current round of modernization on GPS performance. Given this new baseline, opportunities and drivers are identified for the next round of capabilities.
The FAA is looking to develop streamlined launch and reentry licensing requirements for the evolving commercial space industry. A central goal is to move from prescriptive requirements to performance ...requirements. By focusing on outcomes, performance standards give to developers flexibility and make it possible to find lowest-cost means to achieve compliance. Performance standards can generally accommodate technological change and the emergence of new technology driven hazards in ways that prescriptive standards cannot. However, how performance standards are designed and how they are implemented and enforced matters greatly. This paper uses the case of the Boeing B-737 MAX MCAS certification to illustrate the following mistakes to be avoided when using performance-based safety requirements: excessive trust on quantitative performance requirements, inadequate risk-based design process, and lack of independent design verification by experts.
Marine industries face a number of risks that necessitate careful analysis prior to making decisions on the siting of operations and facilities. An important emerging regulatory framework on ...environmental sustainability for business operations is the International Finance Corporation’s Performance Standard 6 (IFC PS6). Within PS6, identification of biodiversity significance is articulated through the concept of “Critical Habitat”, a definition developed by the IFC and detailed through criteria aligned with those that support internationally accepted biodiversity designations. No publicly available tools have been developed in either the marine or terrestrial realm to assess the likelihood of sites or operations being located within PS6-defined Critical Habitat. This paper presents a starting point towards filling this gap in the form of a preliminary global map that classifies more than 13 million km2 of marine and coastal areas of importance for biodiversity (protected areas, Key Biodiversity Areas KBA, sea turtle nesting sites, cold- and warm-water corals, seamounts, seagrass beds, mangroves, saltmarshes, hydrothermal vents and cold seeps) based on their overlap with Critical Habitat criteria, as defined by IFC. In total, 5798×103km2 (1.6%) of the analysis area (global ocean plus coastal land strip) were classed as Likely Critical Habitat, and 7526×103km2 (2.1%) as Potential Critical Habitat; the remainder (96.3%) were Unclassified. The latter was primarily due to the paucity of biodiversity data in marine areas beyond national jurisdiction and/or in deep waters, and the comparatively fewer protected areas and KBAs in these regions. Globally, protected areas constituted 65.9% of the combined Likely and Potential Critical Habitat extent, and KBAs 29.3%, not accounting for the overlap between these two features. Relative Critical Habitat extent in Exclusive Economic Zones varied dramatically between countries. This work is likely to be of particular use for industries operating in the marine and coastal realms as an early screening aid prior to in situ Critical Habitat assessment; to financial institutions making investment decisions; and to those wishing to implement good practice policies relevant to biodiversity management. Supplementary material (available online) includes other global datasets considered, documentation and justification of biodiversity feature classification, detail of IFC PS6 criteria/scenarios, and coverage calculations.
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•A global map identifying potential and likely Critical Habitat, marine and coastal.•Critical Habitat as per ‘International Finance Corporation Performance Standard 6’.•Eleven biodiversity features: protected areas, seagrass beds, corals, seeps, etc.•The ocean was 1.6% ‘Likely Critical Habitat’, and 2.1% ‘Potential Critical Habitat’.•The map can be used as an early screening aid by industries.
Glucose meter performance specifications provide limits for 95% of results, which is the same as total error. A popular total error model is that total error equals (average) bias plus 2 times ...imprecision. This model has been used to specify combinations of average bias and imprecision that satisfy total error goals. But this model is incomplete and its conclusions are suspect. It is shown that when interferences occur in glucose meters as exemplified by hematocrit interference, the total error model proposed by Boyd and Bruns cannot distinguish between meters that differ in performance. The CLSI standard EP21-A, does not have this problem because it directly estimates total error bypassing the need for a model. An example illustrates these points.
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