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At least 73 records · Page 4
All sourcesNASA NTRSDOE OSTI
NASA NTRS2011

Radiative Forcing Over Ocean by Ship Wakes

Changes in surface albedo represent one of the main forcing agents that can counteract, to some extent, the positive forcing from increasing greenhouse gas concentrations. Here, we report on enhanced ocean reflectance from ship wakes over the Pacific Ocean near the California coast, where we determined, based on airborne radiation measurements that ship wakes can increase reflected sunlight by more than 100%. We assessed the importance of this increase to climate forcing, where we estimated the global radiative forcing of ship wakes to be -0.00014 plus or minus 53% Watts per square meter assuming a global distribution of 32331 ships of size of greater than or equal to 100000 gross tonnage. The forcing is smaller than the forcing of aircraft contrails (-0.007 to +0.02 Watts per square meter), but considering that the global shipping fleet has rapidly grown in the last five decades and this trend is likely to continue because of the need of more inter-continental transportation as a result of economic globalization, we argue that the radiative forcing of wakes is expected to be increasingly important especially in harbors and coastal regions.

Gatebe, Charles K.↗
DOE OSTI2011

Lead sheathing of ship hulls in the Roman period: Archaeometallurgical characterisation

An archaeometallurgical analysis of samples of lead sheathing from five ships of the Roman period was carried out in order to determine their composition and microstructure, and to obtain a better understanding of their manufacturing processes. The examinations included optical microscopy of metallographic cross-sections, microhardness tests, scanning electron microscopy, including energy dispersive spectroscopy, and X-ray photoelectron spectroscopy. The results show that the samples were all composed of lead covered with an oxide layer. The sheet thicknesses, microhardness values and microhardness distribution, as well as the grain size distribution, led to the conclusion that all of the sheets were produced by the same technology, using hammering, and were probably used for the same purpose. The presence of antimony was observed in the sample from the Roman ship from Caesarea, which may hint at an Italian (Sardinian) origin of the material, and perhaps of the ship. - Research Highlights: {yields} During the Roman period ship hulls were sheathed with lead. {yields} Five samples have been analysed for their characteristics and manufacturing process. {yields} The process was cold-working (strain-hardening) using hammering. {yields} The lead was open-casted on a flat stone, and later hammered at room temperature. {yields} Antimony in the Caesarea shipwreck may indicate an Italian origin of construction.

36 MATERIALS SCIENCE↗
DOE OSTI2021

Adoption of Biofuels for the Marine Shipping Industry: A Long-Term Price and Scalability Assessment

One of the biggest challenges in the 21st Century is transforming the transportation sector into a low carbon-based sustainable industry, including maritime shipping. Bioenergy has an essential role in the transition to move maritime shipping toward carbon neutrality. Biomass-derived fuels can undoubtedly play a crucial role in the future of marine propulsion that as renewable alternatives can offer potential synergistic benefits when blended with petroleum fuels. With inherently zero- or low-sulfur and renewable carbon sources, biofuels will help mitigate marine shipping sulfur emissions, improve overall emission profiles, and enable the decarbonization transition. As biofuel for marine propulsion is still at its nascent stage, knowledge gaps exist, including the life cycle environmental impacts, compatibility of biofuel blending with conventional marine fuels, scalability, and cost. This study assessed the biofuel availability and cost aspects for marine use and was supported by the U.S. Department of Transportation’s Maritime Administration (MARAD) Office of Environment to project the long-term price and annual biofuel production capacity potential for marine propulsion in the United States. The study will shed light on the prospect of biofuel adoption for the maritime shipping industry.

09 BIOMASS FUELS↗
NASA NTRS1991

Aircraft Ship Operations

The interest in the use of shipborne aircraft is widespread among NATO countries. Major weapons systems like aircraft carriers with conventional fixed-wing aircraft, VSTOL aircraft or helicopters embarked, are operated by the United States, the United Kingdom, France, Italy and Spain. Nearly all NATO countries employ various classes of smaller ships as helicopter platforms for amphibious assault, anti-submarine warfare or search and rescue. The deployment of aircraft on board ships presents unusual and difficult technical and operational problems. Considering the multi-national interest in aircraft/ship operations it was considered meaningful and timely for the Flight Mechanics Panel to sponsor a symposium on this topic. This symposium considered problems of mutual interest connected with fixed and rotary wing aircraft operations from ships, and the application of new technology to enhance such operations. The Symposium reviewed and assessed the current problems and possible future progress in: - The ship environment in terms of wind, temperature, precipitation, turbulence and deck motion. - Guidance, Controls and Displays, primarily in the approach and landing phase. - Flight Test and Simulation Techniques. - Launch, Recovery and Handling Systems Developments. - Operational/Pilot Views. - Future Developments.

Aircraft carriers↗
DOE OSTI2014

THERMAL EVALUATION OF ALTERNATE SHIPPING CASK FOR GTRI EXPERIMENTS

The Global Threat Reduction Initiative (GTRI) has many experiments yet to be irradiated in support of the High Performance Research Reactor fuels development program. Most of the experiments will be irradiated in the Advanced Test Reactor (ATR) at Idaho National Laboratory (INL), then later shipped to the Hot Fuel Examination Facility (HFEF) located at the Materials and Fuels Complex for post irradiation examination. To date, the General Electric (GE)-2000 cask has been used to transport GTRI experiments between these facilities. However, the availability of the GE-2000 cask to support future GTRI experiments is at risk. In addition, the internal cavity of the GE-2000 cask is too short to accommodate shipping the larger GTRI experiments. Therefore, an alternate shipping capability is being pursued. The Battelle Energy Alliance, LLC, Research Reactor (BRR) cask has been determined to be the best alternative to the GE-2000 cask. An evaluation of the thermal performance of the BRR cask is necessary before proceeding with fabrication of the newly designed cask hardware and the development of handling, shipping, and transport procedures. This paper presents the results of the thermal evaluation of the BRR cask loaded with a representative set of fueled and non-fueled experiments. When analyzed with identical payloads, experiment temperatures were found to be lower with the BRR cask than with the GE-2000 cask. From a thermal standpoint, the BRR cask was found to be a suitable alternate to the GE-2000 cask.

42 ENGINEERING↗
DOE OSTI2025

Ship Motion Testing Needs Evaluation

The American Bureau of Shipping performed an evaluation of national maritime nuclear testing capabilities and determined there currently is an inability to test maritime nuclear power plants in a ship motion environment. A Ship Motion Test Facility (SMTF) is proposed to fill this gap. To inform design of this facility, this report documents an evaluation performed by a panel of technical experts that identifies key physical phenomena associated with maritime nuclear power plant operation that are important to safety and reliability and have a low state of knowledge. This evaluation concluded that all of the major test needs to understand a nuclear plant's behavior in a ship motion environment are for thermal-hydraulics related phenomena. Based on this finding, the evaluation panel concluded that the SMTF would not be required to use nuclear fuel to provide a heat source for the fluids. This would significantly decrease the cost, timeline, and complexity for this test facility to enable the advancement of maritime nuclear technology.

22 - GENERAL STUDIES OF NUCLEAR REACTORS↗
DOE OSTI2024

Design of Muon Campus full flow purifier for varying operational conditions and horizontal shipping

Constant ingress of impurities in Muon Campus g-2 experiment at Fermilab has resulted in reduction of efficiency of cryogenic expanders and occasional undesired downtime to flush the impurities. Due to insufficiency of current 0.06 kg/s mobile purifier, a full flow purifier is designed to be used in Muon Campus which purifies 0.24 kg/s of Helium throughput of 4 compressors through charcoal bed at 80 K and returns ambient Helium back to the system. The purifier is designed to be operated near liquid Nitrogen temperature during cold operations and up to 400 K during regeneration. Both warm and cold operational range of the purifier has required use of appropriate clearances in design due to expansion and contraction. The vessel of around 5.5 m height which is designed to be operated vertically is to be shipped horizontally. The asymmetrical position of heavy stainless steel heat exchanger in the purifier support frame and 5g vertical load design consideration for shipping has required use of shipping supports and heat exchanger rotational stops to comply with design requirements. FEA of purifier system is performed in cold, warm and shipping cases to verify that the purifier satisfies the design requirements.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2018

Compression Stress-Relaxation and Oxygen Consumption Behavior of 9975 Shipping Package O-rings

The 9975 shipping package is used within the DOE complex for shipping special nuclear materials. The shipping packages are currently approved for up to 20 years storage in K-Area Complex (KAC) and work continues to provide technical basis to extend that period. Several techniques have been used at Savannah River National Laboratory to monitor the aging performance of Viton ® GLT or GLT-S fluoroelastomer O-rings. These experiments all involve accelerated aging of the O-ring samples at elevated temperatures. This report describes efforts to extend the service life estimate of GLT and GLT-S O-rings used in the 9975 shipping package.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2018

Understanding the Opportunities of Biofuels for Marine Shipping

This report examines the potential benefits, feasibility, and barriers to the use of biofuels in place of heavy fuel oil (HFO) and marine gas oil for marine vessels. More than 90% of world’s shipped goods travel by marine cargo vessels powered by internal combustion (diesel) engines using primarily low-cost residual HFO, which is high in sulfur content. Recognizing that marine shipping is the largest source of anthropogenic sulfur emissions and is a significant source of other pollutants including particulates, nitrogen oxides, and carbon dioxide (CO 2 ), the International Maritime Organization enacted regulations to lower the fuel sulfur content from 3.5 wt.% to 0.5 wt.% in 2020. These regulations require ship operators either to use higher-cost, low-sulfur HFO or to seek other alternatives for reducing sulfur emissions (i.e., scrubbers, natural gas, distillates, and/or biofuels). The near-term options for shipowners to comply with regulations include fueling with low-sulfur HFO or distillate fuels or installing emissions control systems. However, few refineries are equipped to produce low-sulfur HFO. Likewise, the current production rates of distillates do not allow the necessary expansion required to fuel the world fleet of shipping vessels (which consume around 330 million metric tons). This quantity is more than twice that used in the United States for cars and trucks. The other near-term option is to install emission control systems, which also requires a significant investment. All of these options significantly increase operational costs. Because of such costs, biofuels have become an attractive alternative since they are inherently low in sulfur and potentially also offer greenhouse gas benefits. Based on this preliminary assessment, replacing HFO in large marine vessels with minimally processed, heavy biofuels appears to have potential as a path to reduced emissions of sulfur, CO 2 , and criteria emissions. Realizing this opportunity will require deeper knowledge of (1) the combustion characteristics of biofuels in marine applications, (2) their compatibility for blending with conventional marine fuels (including HFO), (3) needs and costs for scaling up production and use, and (4) a systems assessment of their life cycle environmental impacts and costs. It is recommended that a research program investigating each of these aspects be undertaken to better assess the efficacy of biofuels for marine use.

09 BIOMASS FUELS↗
DOE OSTI2011

Early ship-based upper-air data and comparison with the Twentieth Century Reanalysis

Extension of 3-D atmospheric data products back into the past is desirable for a wide range of applications. Historical upper-air data are important in this endeavour, particularly in the maritime regions of the tropics and the southern hemisphere, where observations are extremely sparse. Here we present newly digitized and re-evaluated early ship-based upper-air data from two cruises: (1) kite and registering balloon profiles from onboard the ship SMS Planet on a cruise from Europe around South Africa and across the Indian Ocean to the western Pacific in 1906/1907, and (2) ship-based radiosonde data from onboard the MS Schwabenland on a cruise from Europe across the Atlantic to Antarctica and back in 1938/1939. We describe the data and provide estimations of the errors. We compare the data with a recent reanalysis (the Twentieth Century Reanalysis Project, 20CR, Compo et al., 2011) that provides global 3-D data back to the 19th century based on an assimilation of surface pressure data only (plus monthly mean sea-surface temperatures). In cruise (1), the agreement is generally good, but large temperature differences appear during a period with a strong inversion. In cruise (2), after a subset of the data are corrected, close agreement between observations and 20CR is found for geopotential height (GPH) and temperature notwithstanding a likely cold bias of 20CR at the tropopause level. Results are considerably worse for relative humidity, which was reportedly inaccurately measured. Note that comparing 20CR, which has limited skill in the tropical regions, with measurements from ships in remote regions made under sometimes difficult conditions can be considered a worst case assessment. In view of that fact, the anomaly correlations for temperature of 0.3–0.6 in the lower troposphere in cruise (1) and of 0.5–0.7 for tropospheric temperature and GPH in cruise (2) are considered as promising results. Moreover, they are consistent with the error estimations. The results suggest room for further improvement of data products in remote regions.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2024

Exploring ship track spreading rates with a physics-informed Langevin particle parameterization

Abstract. The rate at which aerosols spread from a point source injection, such as from a ship or other stationary pollution source, is critical for accurately representing subgrid plume spreading in a climate model. Such climate model results will guide future decisions regarding the feasibility and application of large-scale intentional marine cloud brightening (MCB). Prior modeling studies have shown that the rate at which ship plumes spread may be strongly dependent on meteorological conditions, such as precipitating versus non-precipitating boundary layers and shear. In this study, we apply a Lagrangian particle model (PM-ABL v1.0), governed by a Langevin stochastic differential equation, to create a simplified framework for predicting the rate of spreading from a ship-injected aerosol plume in sheared, precipitating, and non-precipitating boundary layers. The velocity and position of each stochastic particle is predicted with the acceleration of each particle being driven by the turbulent kinetic energy, dissipation rate, momentum variance, and mean wind. These inputs to the stochastic particle velocity equation are derived from high-fidelity large-eddy simulations (LES) equipped with a prognostic aerosol–cloud microphysics scheme (UW-SAM) to simulate an aerosol injection from a ship into a cloud-topped marine boundary layer. The resulting spreading rate from the reduced-order stochastic model is then compared to the spreading rate in the LES. The stochastic particle velocity representation is shown to reasonably reproduce spreading rates in sheared, precipitating, and non-precipitating cases using domain-averaged turbulent statistics from the LES.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2012

ARM Navigation Best Estimate 10 Hz (NAVBE) and 1-min (NAVBE1M) Value Added Products (VAP) for Ship Deployments

The Navigation Best Estimate (NAVBE) VAP was developed in response to the 2012-2013 Marine ARM GPCI Investigation of Clouds (MAGIC) deployment, the first ship-based deployment of the second ARM Mobile Facility (AMF2). It has since been applied to the 2015 ARM Cloud Aerosol Precipitation EXperiment (ACAPEX) deployment. A number of different instruments on the ships collected Global Positioning System (GPS) and Inertial Navigation System (INS) measurements during the MAGIC campaign. The motivation of the NAVBE VAP is to consolidate many different sources of this information in a single, continuous datastream to be used when information is required about ship location and orientation and to provide a more complete estimate than would be available from any one instrument. The result is 10 Hz and 1-min data streams reporting ship position and attitude

54 ENVIRONMENTAL SCIENCES↗
NASA NTRS1972

A technique for breaking ice in the path of a ship

A technique is described for breaking ice in the path of a ship. A laser is placed on the bow of the ship with apparatus to scan the ice in the path of the ship with the laser beam. The beam cuts or shatters the ice, enabling the ship to break the ice in its path.

Saunders, A. R.↗
NASA NTRS1977

Seakeeping considerations in the employment of V/STOL on Naval ships

Compatibility of Naval ships as V/STOL support platforms and the ship motions that V/STOL aircraft must endure are discussed. A methodology which evaluates the impact of motion criteria such as the maximum ship motion allowable during V/STOL landing/launch is presented. Emphasis is given to design alternatives that reduce ship motion.

Olson, S. R.↗
NASA NTRS1981

A low cost maritime control aircraft-ship-weapons system

It is pointed out that the long-range antiship standoff missile is emerging as the foremost threat on the seas. Delivered by high speed bombers, surface ships, and submarines, a missile attack can be mounted against selected targets from any point on the compass. An investigation is conducted regarding the configuration of a system which could most efficiently identify and destroy standoff threats before they launch their weapons. It is found that by using ships for carrying and launching missiles, and employing aircraft with a powerful radar only for search and missile directing operations, aircraft cost and weight can be greatly reduced. The employment of V/STOL aircraft in preference to other types of aircraft makes it possible to use ships of smaller size for carrying the aircraft. However, in order to obtain an all-weather operational capability for the system, ships are selected which are still big enough to display the required stability in heavy seas.

Fluk, H.↗
NASA NTRS1985

An investigation into the vertical axis control power requirements for landing VTOL type aircraft onboard nonaviation ships in various sea states

The problem of determining the vertical axis control requirements for landing a VTOL aircraft on a moving ship deck in various sea states is examined. Both a fixed-base piloted simulation and a nonpiloted simulation were used to determine the landing performance as influenced by thrust-to-weight ratio, vertical damping, and engine lags. The piloted simulation was run using a fixed-based simulator at Ames Research center. Simplified versions of an existing AV-8A Harrier model and an existing head-up display format were used. The ship model used was that of a DD963 class destroyer. Simplified linear models of the pilot, aircraft, ship motion, and ship air-wake turbulence were developed for the nonpiloted simulation. A unique aspect of the nonpiloted simulation was the development of a model of the piloting strategy used for shipboard landing. This model was refined during the piloted simulation until it provided a reasonably good representation of observed pilot behavior.

Stevens, M. E.↗
NASA NTRS1990

A comparison of ship and Coastal Zone Color Scanner mapped distribution of phytoplankton in the southeastern Bering Sea

Twenty-one Coastal Zone Color Scanner (CZCS) images of the southeastern Bering Sea are examined in order to map the near-surface distribution of phytoplankton during 1979 and 1980. The information is compared with the mesoscale (100-1000 km) distribution of phytoplankton inferred from pooled ship sampling obtained during the Processes and Resources of the Bering Shelf (PROBES) intensive field study during the late 1970s and early 1980s. The imagery indicates that open-water phytoplankton blooms occur first in late April in coastal waters, peak in early May over the middle shelf, and decay rapidly afterwards, reaching concentration minima in June in both regions. These patterns show that the earlier ship observations are valid for most of the eastern Bering shelf. A very tight correlation is found between the PROBES surface chlorophyll a concentrations and mean mixed-layer chlorophyll concentrations. The significant discrepancies between CZCS and ship-based chlorophyll estimates may be due to aliasing in time by the CZCS. It is concluded that neither satellite nor ship alone can do an adequate job of characterizing the physics or biological dynamics of the ocean.

Mcclain, C. R.↗
NASA NTRS2001

Reduction of Cloud Water in Ship Tracks: Observations and Large-Eddy Simulations

Ship tracks represent a natural laboratory to study the effects of aerosols on clouds. A number of observations and simulations have shown that increased droplet concentrations in ship tracks increase their total cross-sectional area, thereby enhancing cloud albedo and providing a negative radiative forcing at the surface and the top of the atmosphere. In some cases, cloud water has been found to be enhanced in ship tracks, which has been attributed to suppression of drizzle and implies an enhanced susceptibility of cloud albedo to droplet concentrations. However, more recently compiled observations indicate that cloud water is instead reduced in daytime ship tracks on average. Such a response is consistent with cloud-burning due to solar absorption by soot (the semi-direct radiative forcing of aerosols), recently suggested to be suppressing trade cumulus cloud coverage over the Indian Ocean. We will summarize observational evidence and present large-eddy simulations that consider these competing mechanisms in the effects of aerosols on cloud albedo.

Ackerman, A. S.↗