Candidate Options Research Articles

Determining Colors for Traffic Control Devices at Transponder-Controlled Tollbooth Lanes with a Sign Simulator

The number of toll roads is increasing in the United States, and drivers face signing practices that vary greatly across jurisdictions. In addition to the increase in toll roads, there is an increase in the use of electronic toll collection (ETC) transponders. The present study was undertaken to develop standard signing practices—specifically for background color, legend color, underlay color (i.e., the background color for the pictographs), and pictograph—for ETC-supported toll road signs. The study reviewed selected ETC toll road signs in the United States to help select candidate elements and options to be used in a laboratory experiment. On the basis of that review, 120 signs depicted on 35-mm slides were developed with a standard sign-design software package. The signs were presented to 60 participants (equally divided by sex and age group) in the recently updated Turner–Fairbank Highway Research Center's sign simulator. The signs were shown to participants starting at a simulated distance of approximately 1,125 ft (343 m), and then the image was zoomed toward the participants at a constant speed controlled by the laboratory's computer. Each participant's detection distance, guidance legibility distance, and pictograph legibility distance were recorded. The results showed that, overall, green as a background color obtained the longest guidance information legibility distance. Also, fonts that provided the highest contrast to the background color (such as white on black) were the most effective for legibility. Underlay colors that showed the highest contrast to the pictographs were the most effective and included all of the lighter colors tested (white, yellow, and blue).

Sustainable urban transportation: impact of CO<SUB align=right>2 mitigation strategies on local pollutants

This paper assesses CO2 mitigation strategies in Delhi and Mumbai against the dynamics of local pollutants. After testing against techno-economic feasibility, compressed natural gas (CNG) technology, four-stroke two-wheelers and battery-operated vehicles (BOV) were selected as candidate options for Mumbai and Delhi. Multiple constrained optimisation for finding out the optimal mix of vehicles to meet the travel demand under the business-as-usual scenario for the period of CO2 mitigation targets of 5, 10, 15, 20, 25% resulted in reduced stock of diesel and petrol vehicles, with the reduction spanning over different points of the above time period. In the case of Mumbai, battery-operated three-wheelers dominated the vehicular mix, with the share of CNG vehicles remaining at a standard level. CO2 reduction targets did not influence the CNG option significantly. CO2 mitigation influenced the dynamics of local pollutants considerably in both Delhi and Mumbai. In Delhi, TSP and SOx reduction levels against the CO2 mitigation target were found to be significant. In Mumbai, the percentage reduction in local pollution (TSP in particular) was higher than the target CO2 reduction. Local pollutants other than TSP and SOx showed an increasing trend against the CO2 mitigation strategies in Delhi. In the case of Mumbai, all non-target pollutants showed a falling trend against the CO2 mitigation strategies, though insignificantly for pollutants other than TSP and SOx.

Review and evaluation of methods for application of epitaxial buffer and superconductor layers

Abstract The recent achievements of critical currents exceeding 1,000,000 amps/cm 2 at 77 K in YBCO deposited over suitably textured substrate have stimulated interest in the potential applications of coated conductors at high temperatures and in high magnetic fields. Currently, ion-beam assisted deposition (IBAD), and rolling assisted bi-axially textured substrate (RABiTS), represent two available options for obtaining textured substrates. For applying suitable coatings of buffer and high temperature superconductor (HTS) material over textured substrates, several options are available which include sputtering, electron-beam evaporation, laser ablation, electrophoresis, chemical vapor deposition (including metal organics chemical vapor deposition), sol-gel, metal organics decomposition, electrodeposition and aerosol/spray pyrolysis. A commercial continuous long-length wire/tape manufacturing scheme developed out of any suitable combination of the above techniques would consist of operations involving preparation of the substrate and application of buffer, HTS and passivation/insulation materials and special treatment steps such as post-annealing. These operations can be effected by various process parameters that can be classified into chemistry, materials, engineering and environmental related parameters. To carry out an engineering evaluation: (i) the process flow schemes were developed for various candidate options identifying the major operating steps, process conditions, and process streams; (ii) to evaluate quantifiable parameters such as process severity (e.g. temperature and pressure), coating thickness and deposition rate for HTS material, achieved maximum J c value, and cost of chemicals and material utilization efficiency, the multi-attribute method was used to determine attributes/merits for various parameters and candidate options. To determine similar attribute values for the non-quantifiable parameters, a subjective evaluation was used. Results of the two evaluations were then combined to calculate the overall merit/utility of a given option using weighting factors. To evaluate the effect of arbitrarily determined weighting factors, a sensitivity analysis was carried out by using three different sets of weighting factors. In the end, the results of the overall utility/merit values calculated using different sets of weighting factors were utilized to determine the preliminary ranking among the candidate options. The process flow schemes developed for various options, as well as the results of the engineering evaluation carried out for the candidate options using these schemes, are given in this paper.

Plutonium disposition in the BN-600 fast-neutron reactor at the Beloyarsk nuclear power plant

In 1996, the United States and the Russian Federation completed an initial joint study that evaluated the candidate options for the disposition of surplus weapons-derived plutonium in both countries. While Russia advocates building new reactors for converting weapons-derived plutonium to spent fuel, the cost is high, and the continuing joint study of the Russian options is considering only the use of the existing VVER-1000 LWRs in Russia (and possibly in Ukraine) and the existing BN-600 fast-neutron reactor at the Beloyarsk Nuclear Power Plant in Russia. The BN-600 reactor, which currently uses enriched uranium fuel, is capable with certain design modifications of converting up to 1.3 metric tons (MT) of surplus weapons-derived plutonium to spent fuel each year. The steps needed to convert BN-600 to a plutonium-burner core will be discussed. The step involving the hybrid core allows an early and timely start that takes advantage of the limited capacity for fabricating uranium–plutonium mixed-oxide fuel early in the disposition program. The design lifetime of BN-600 must safely and reliably be extended by 10 yr to at least 2020 so that a sufficient amount of plutonium (∼20 MT) can be converted to spent fuel.

Assessment of Options for Attractive Commercial and Demonstration Tokamak Fusion Power Plants

The Starlite Project was initiated to investigate the mission, requirements and goals, features, and the R&D needs of the Fusion Demonstration Power Plant based on tokamak confinement concept. It is obvious that the Fusion Demo should demonstrate that a commercial fusion power plant would be accepted by utility and industry (i.e., it is affordable and profitable) and by the general public and government (i.e., it has superior safety and environmental features). Therefore, as the first step in the Starlite project, a set of quantifiable top-level requirements, and goals for both commercial fusion power plants and the Fusion Demo were developed. Next, several candidate options for physics operation regime as well engineering design of various components (e.g., choice of structural material, coolant, breeder) have been developed and assessed. In each area, this assessment was aimed at investigating (1) the potential to satisfy the requirements and goals, and (2) the feasibility e.g., critical issues and credibility (e.g., degree extrapolation required from present data base). This assessment led to the choice of the reversed-shear as the tokamak plasma operation regime and a self-cooled lithium design with vanadium alloy for blanket and in-vessel structures for detailed design. This paper presents a summary of top-level requirements and goals for fusion power and overviews the results of our assessment of tokamak plasma physics and technology options and designs.