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At least 163 records · Page 9

Primer on the Cost of Marine Fuels Compliant with IMO 2020 Rule

This report aims to provide information for owners and operators of U.S. ocean-going marine cargo vessels on the cost of different approaches to compliance with the IMO mandate to reduce the sulfur content of marine fuels (outside emission control areas) to no more than 0.5%. The IMO 2020 rule came into effect on January 1, 2020. The report discusses a suite of options for compliance including low-sulfur petroleum-based fuels and alternative fuels. Since fuel prices are a primary factor in determining the cost of the various alternatives, the document also includes a discussion of the main drivers of marine fuel prices. The cost analysis compares the average annual costs (capital and fuel) out to 2050 of each compliance approach under alternative scenarios regarding fuel prices, policy, and technology innovation. The cost calculations focus on representative U.S. fleet vessels for containership and tanker types. Even though the analysis focuses on average cost of approaches to comply with IMO 2020, the comparison of approaches also acknowledges other benefits or risks including fuel price risk and the contribution of the approach to achieving other potential environmental performance objectives or regulations.

02 PETROLEUM↗

Potential safety impacts associated with production of gaseous PuF 6 due to reactions between 3013-compliant PuO 2 with Novec TM 1230 at temperature

A part of the NNSA/SRNS Surplus Plutonium Disposition (SPD) project is a planned expansion of an existing facility with capabilities to handle, process, package, and characterize large amounts of plutonium oxide materials for permanent disposition at WIPP. The facility design for this future processing capability will include glovebox operations, HEPA filters, and exhaust/ventilation systems. An NNSA review of the facility support systems included comments on the potential residual reactivity of previously-stabilized PuO 2 , and on the possibility of chemical interactions between stabilized PuO 2 and a new fire suppressant (Novec TM 1230), a replacement for chlorinated/brominated compounds such as HALON TM , to be employed in the event of a room/glovebox fire where PuO 2 will be processed.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗

L4-3 Developing DOE M441.1-1 Compliant Container Components: Filter Cup Experimental Fixture Test Data Verification

This document serves to provide technical documentation and justification for using the Filter Cup Experimental Fixture (FCEP) for filter efficiency and pressure drop testing in the Enhanced Filter Test System (EFTS). This document assumes that the reader has prior knowledge related to both of these systems, as well as the SAVY-4000® nuclear material container series filter technology.

42 ENGINEERING↗

Dynamic Wind Loading on Compliant, Floating PV Arrays: Cooperative Research and Development (Final Report)

PV panels are subjected to wind loads during normal outdoor operation, where th wind speed, wind direction, panel angle, and array layout play a large role in the overall loading magnitude. For floating PV systems, where panels are installed on floating rafts, these forces can lead to a dynamic displacement of the raft and mounted PV hardware. The Contractor and Participant will perform fluid-structure interaction simulations of this phenomenon for a variety of wind speeds, directions, and panel angles to characterize these forces and help design mooring/tethering lines to resist and anchor raft movement.

14 SOLAR ENERGY↗

Transient Stability Study of IEEE 2800-2022 Standard Negative-Sequence-Current Compliant GFM IBRs

The primary function of grid-forming (GFM) inverter-based resources (IBRs) is to maintain voltage and fre- quency/phase angle stability; however, during unbalanced grid faults, IEEE Std. 2800-2022 requires IBRs to inject both positive- and negative-sequence reactive current. Enforcing compliance with this standard could compromise the stability of GFM IBRs under such fault conditions. This paper presents a preliminary transient stability study focused on the power angle stability of GFM IBRs operating in compliance with IEEE Std. 2800 during unbalanced faults. The goal is to assess potential stability issues associated with the standard's current injection requirements under fault ride-through conditions. The results show that injecting positive-sequence current with d-axis priority during unbalanced faults better preserves the power angle stability than the q-axis priority while still enabling negative-sequence current injection. These findings suggest that, to ensure stability, GFM IBRs might need to partially comply with IEEE Std. 2800 by prioritizing positive-sequence current injection along the d-axis.

14 SOLAR ENERGY↗

Studying the Impact of Momentary Cessation of IBRs Compliant With IEEE Std. 2800-2022 on Transmission Line Protection Elements

This paper examines the impact of inverter-based resource (IBR) momentary cessation timing on transmission system protection relays. IEEE Std. 2800 mandates voltage ride-through, requiring IBRs to remain online during voltage disturbances. However, for severe voltage dips (|V| = 0.1 p.u.), the standard permits current blocking. In practice, vendors implement momentary cessation with varying delays, potentially affecting relay operation if IBRs cease too early. This article studies the impact of the time IBRs enter momentary cessation on transmission line protective relays. Using an electromagnetic transient (EMT) simulation, this study models IBR momentary cessation with tunable delays in a realistic transmission network. COMTRADE files generated from EMT simulations are analyzed in MATLAB using detailed protective relay models. Results indicate that IBRs must sustain operation for at least one cycle to ensure proper relay response; otherwise, relays may fail to oper- ate. These findings guide IBR vendors in optimizing momentary cessation settings to enhance transmission line protection.

24 POWER TRANSMISSION AND DISTRIBUTION↗

Forced vibrations of multi-component compliant tanks and feedlines

An analytical and experimental research program was performed to investigate the effects of flexible tanks and lines and the total system dynamic response of a simple physical system which had some of the essential features of a liquid-fueled launch vehicle. Several vessel-wall materials were used to obtain a range of elastic moduli. Water was used to simulate the fuel and an electromagnetic shaker provided external excitation such as might originate from a rocket-propulsion system. Experimental data were compared to values obtained from mathematical models for the many degree-of-freedom lumped-mass representation.

Smith, H. W.↗

Analysis and compensation of an aircraft simulator control loading system with compliant linkage

A hydraulic control loading system for aircraft simulation was analyzed to find the causes of undesirable low frequency oscillations and loading effects in the output. The hypothesis of mechanical compliance in the control linkage was substantiated by comparing the behavior of a mathematical model of the system with previously obtained experimental data. A compensation scheme based on the minimum integral of the squared difference between desired and actual output was shown to be effective in reducing the undesirable output effects. The structure of the proposed compensation was computed by use of a dynamic programing algorithm and a linear state space model of the fixed elements in the system.

Johnson, P. R.↗

Design and performance of compliant thrust bearing with spiral-groove membranes on resilient supports

Novel thrust bearings with spiral-groove flexible membranes mounted on resilient supports were designed and their performance demonstrated. Advantages of surface compliance were combined with the superior load-capacity of the spiral-groove geometry. Loads of 127-150N were supported on an area 42 sq cm, at speeds of 43,000-45,000 rpm and mean clearances of 15-20 microns. Support-worthiness was proved when tested in conjunction with foil journal-bearings and a 19N rotor, excited in a pitching mode by a total unbalance of 43 micron-N.

Licht, L.↗

Experimental investigation of drag on a compliant surface

The feasibility of reducing turbulent skin-friction drag by means of surface compliance was studied experimentally in a fully developed flat-plate turbulent boundary layer in air, using a membranous surface backed by a thin cavity containing a layer of polyurethane foam. Surface motion characteristics, boundary layer structure, and overall drag were measured over a range of freestream speeds from 7 to 30 m/sec, and a range of membrane tensions from 44 to 350 N/m. Low-amplitude long-wavelength motions predominate, and no significant change from the rigid surface skin-friction coefficients was observed.

Mcmichael, J. M.↗

Fully plasma-sprayed compliant backed ceramic turbine seal

A seal with a high temperature abradable lining material which encircles the tips of turbine blades in turbomachinery was designed. The seal is directed to maintaining the minimum operating clearances between the blade tips and the lining of a high pressure turbine. A low temperature easily decomposable material in powder form is blended with a high temperature oxidation resistant metal powder. The two materials are simultaneously deposited on a substrate formed by the turbine casing. Alternately, the polymer powder may be added to the metal powder during plasma spraying. A ceramic layer is then deposited directly onto the metal-polymer composite. The polymer additive mixed with the metal is then completely volatilized to provide a porous layer between the ceramic layer and the substrate. Thermal stresses are reduced by the porous structure which gives a cushion effect. No brazing is required by using only plasma spraying for depositing both the powders of the metal and polymer material as well as the ceramic powder.

Bill, R. C.↗

Fully plasma-sprayed compliant backed ceramic turbine seal

A seal having a high temperature abradable lining material encircling the tips of turbine blades in turbomachinery is discussed. The minimum operating clearances between the blade tips and the lining of a high pressure turbine are maintained. A low temperature easily decomposable material, such as a polymer, in powder form is blended with a high temperature oxidation resistant metal powder. The two materials are simultaneously deposited on a substrate formed by the turbine casing. Alternately, the polymer powder may be added to the metal powder during plasma spraying. A ceramic layer is then deposited directly onto the metal polymer composite. The polymer additive mixed with the metal is then completely volatilized to provide a porous layer between the ceramic layer and the substrate.

Bill, R. C.↗

A compliant, high failure strain, fibre-reinforced glass-matrix composite

A glass-matrix composite reinforced by discontinuous graphite fibers was produced by hot pressing glass-powder-impregnated two-dimensional arrays of in-plane randomly oriented graphite fibers held together by approximately 5-10% by weight of organic binder (generally polyester). The composite tensile behavior is characterized by a highly nonlinear stress-strain curve which differs markedly from that of either unreinforced glass or a similarly reinforced epoxy-matrix composite. By virtue of this nonlinearity, the composite is able to redistribute applied stresses to achieve a high load-carrying capacity. The fibrous microstructure and the low fiber-matrix bond provide a mechanism for achieving high fracture toughness and unusually high compliance. For a 96%-silica-matrix composite, the strength is retained to over 1000 C.

Prewo, K. M.↗