Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “Unit Testing”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 721 records · Page 40
All sourcesNASA NTRSDOE OSTI
DOE OSTI2015

SECARB Initial Injection Period Reservoir Modeling Report

The Southeast Carbon Sequestration Partnership Phase III Anthropogenic Test at Citronelle Field is the United States’ largest CO 2 capture and transportation, injection, storage and monitoring project using CO 2 derived from a coal-fired power station. The project represents a U.S. Department of Energy research and development initiative designed to demonstrate deep underground injection and containment of 100,000 tonnes or more of anthropogenic-source CO 2 . A series of reservoir modeling runs will be performed during the pre-injection, injection, and post-injection phases of the project and will be used to predict plume migration and areal extent. Pressure, temperature, and downhole measurements (seismic, fluid and logging), all data collected as a part of the monitoring program, are utilized as reservoir performance parameters to tune the existing geophysical and geochemical simulation models. The ability to represent site injection activities with the produced detailed simulation models lend credence to long-term forecasts of CO 2 fate and the progress of the CO 2 plume. This report provides an assessment of the simulation model results for CO 2 injection at the Citronelle Anthropogenic Test site from the period of August 20, 2012 to August 31, 2013.

01 COAL, LIGNITE, AND PEAT↗
DOE OSTI2018

Radionuclide NESHAP Annual Report for CY 2017 Sandia National Laboratories, Nevada Tonopah Test Range

This report provides a summary of the radionuclide releases from the United States (U.S.) Department of Energy (DOE) National Nuclear Security Administration facilities at Sandia National Laboratories/Tonopah Test Range (SNL/TTR) during Calendar Year (CY) 2017, including the data, calculations, and supporting documentation for demonstrating compliance with 40 Code of Federal Regulation (CFR) 61, Subpart H--NATIONAL EMISSION STANDARDS FOR EMISSIONS OF RADIONUCLIDE OTHER THAN RADON FROM DEPARTMENT OF ENERGY FACILITIES (Radionuclide NESHAP).

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2017

Developing High PV Penetration Cases for Frequency Response Study of U.S. Western Interconnection

Recent large penetrations of solar photovoltaic (PV) generation and the inertial characteristics of inverter-based generation technologies have caught the attention of those in the electric power industry in the United States. This paper presents a systematic approach to developing test cases of high penetrations of PV for the Western Interconnection. First, to examine the accuracy of the base case model, the Western Electricity Coordinating Council (WECC) model is validated by using measurement data from synchronized phasor measurement units. Based on the 2022 Light Spring case, we developed four high PV penetration cases for the WECC system that are of interest to the industry: 5% PV+15 % wind, 25% PV+15% wind, 45% PV+15% wind, 65% PV+15% wind). Additionally, a method to project PV is proposed that is based on collected, realistic PV distribution information, including the current and future PV power plant locations and penetrations in the WECC system. Both the utility-scale PV plant and residential rooftop PV are included in this study.

14 SOLAR ENERGY↗
DOE OSTI2016

A New Light Weight Structural Material for Nuclear Structures

Radiation shielding materials are commonly used in nuclear facilities to attenuate the background ionization radiations to a minimum level for creating a safer workplace, meeting regulatory requirements and maintaining high quality performance. The conventional radiation shielding materials have a number of drawbacks: heavy concrete contains a high amount of elements that are not desirable for an effective shielding such as oxygen, silicon, and calcium; a well known limitation of lead is its low machinability and toxicity, which is causing a major environmental concern. Therefore, an effective and environmentally friendly shielding material with increased attenuation and low mass density is desirable. Close-cell composite metal foams (CMFs) and open-cell Al foam with fillers are light-weight candidate materials that we have studied in this project. Close-cell CMFs possess several suitable properties that are unattainable by conventional radiation shielding materials such as low density and high strength for structural applications, high surface area to volume ratio for excellent thermal isolation with an extraordinary energy absorption capability. Open-cell foam is made up of a network of interconnected solid struts, which allows gas or fluid media to pass through it. This unique structure provided a further motive to investigate its application as radiation shields by infiltrating original empty pores with high hydrogen or boron compounds, which are well known for their excellent neutron shielding capability. The resulting open-cell foam with fillers will not only exhibit light weight and high specific surface area, but also possess excellent radiation shielding capability and good processability. In this study, all the foams were investigated for their radiation shielding efficiency in terms of X-ray, gamma ray and neutron. X-ray transmission measurements were carried out on a high-resolution microcomputed tomography (microCT) system. Gamma-emitting sources: 3.0mCi 60 Co, 1.8mCi 137 Cs, 13.5mCi 241 Am, and 5.0mCi 133 Ba were used for gamma-ray attenuation analysis. The evaluations of neutron transmission measurements were conducted at the Neutron Powder Diffractometer beam facility at North Carolina State University. The experimental results were verified theoretically through XCOM and Monte Carlo Z-particle Transport Code (MCNP). A mechanical investigation was performed by means of quasi-static compressive testing. Thermal characterizations were carried out through effective thermal conductivity and thermal expansion analyses in terms of high temperature guarded-comparative-longitudinal heat flow technique and thermomechanical analyzer (TMA), respectively. The experimental results were compared with analytical results obtained from, respectively, Brailsford and Major’s model and modified Turner’s model for verification. Flame test was performed in accordance with United States Nuclear Regulatory Commission (USNRC) standard. CMF sample and a 304L stainless steel control sample were subjected to a fully engulfing fire with an average flame temperature of 800°C for a period of 30 minutes. Finite Element Analysis was conducted to secure the credibility of the experimental results. This research indicates the potential of utilizing the light-weight close-cell CMFs and open-cell Al foam with fillers as shielding material replacing current heavy structures with additional advantage of high-energy absorption and excellent thermal characteristics.

36 MATERIALS SCIENCE↗
DOE OSTI2025

NSTTF Voucher Program RPPR-1 (Final Report)

Sandia issued a Request for Proposals (RFP) to solicit proposals from industry, academia, research laboratories, government agencies, and individuals on the use of the National Solar Thermal Test Facility (NSTTF) to increase CSP technology market adoption across the United States. The voucher funds will be used to cover the cost of NSTTF test facilities usage and technical staff support for analysis, design and test planning and execution. Sandia will collect submitted proposals, coordinate their review through DOE SETO, and work in partnership or under contract with the applicants to complete the funded research. Through this program, participants will be supported in their use of the world class facilities and expertise available at the NSTTF at Sandia in Albuquerque, NM to accelerate the advancement of CST technologies toward meeting 2030 SETO goals for CSP. The goals of this semi-annual reporting period were to complete all administrative tasks and contracting, begin testing on three of the vouchers, and report on initial findings. The fourth voucher (University of Michigan) is predicated on the results of an ongoing heat exchanger test that is expected to conclude by the end of FY22.

14 SOLAR ENERGY↗
DOE OSTI2014

Field Study of Performance, Comfort, and Sizing of Two Variable-Speed Heat Pumps Installed in a Single 2-Story Residence

With the recent advancements in the application of variable-speed (VS) compressors to residential HVAC systems, opportunities are now available to size heat pumps (HPs) to more effectively meet heating and cooling loads in many of the climate zones in the US with limited use of inefficient resistance heat. This is in contrast to sizing guidance for traditional single-speed HPs that limits the ability to oversize with regard to cooling loads, because of risks of poor dehumidification during the cooling season and increased cycling losses. VS-drive HPs can often run at 30-40% of their rated cooling capacity to reduce cycling losses, and can adjust fan speed to provide better indoor humidity control. Detailed air-side performance data was collected on two VS-drive heat pumps installed in a single unoccupied research house in Knoxville, TN, a mixed-humid climate. One system provided space conditioning for the upstairs, while the other unit provided space conditioning for the downstairs. Occupancy was simulated by operating the lights, shower, appliances, other plug loads, etc. to simulate the sensible and latent loads imposed on the building space by internal electric loads and human occupants according to the Building America Research Benchmark (2008). The seasonal efficiency and energy use of the units are calculated. Annual energy use is compared to that of the single speed minimum efficiency HPs tested in the same house previously. Sizing of the units relative to the measured building load and manual J design load calculations is examined. The impact of the unit sizing with regards to indoor comfort is also evaluated.

Munk, Jeffrey D↗
DOE OSTI2026

Bench-Scale Development of Promoted High-Capacity Structured Sorbents (Final Technical Report)

The project objective was to develop high-capacity structured sorbent capable of achieving low CO 2 removal from air. The sorbent framework consists of an amine-functionalized onto hydrophobic polymer backbone with an added promoter. The functionalized amine provides high CO 2 capacity and adsorption rates and the polymer backbone to reduce water uptake. For the sorbent development, multiple functionalized amines and promoters were assessed to select a candidate that achieved high CO 2 capacity, high adsorption rate, and high stability. A sorbent-coated filter design was selected as the structured sorbent, which provides high sorbent loading capacity and contains an electrically conductive nonwoven filter substrate that can be Joule-heated to provide efficient utilization of available electricity for sorbent regeneration. A commercial partner operated a pilot filter manufacturing line to produce the filter panels coated with the developed sorbent. A 1 kg CO 2 /day bench unit was designed and fabricated to test the structured filter sorbent. The key achievements from the structured sorbent development activity were demonstrating that existing filter industrial-scale processes can be used for manufacturing Susteon’s structured sorbent and completing a proof-of-concept demonstration of the commercially manufactured structured sorbent filters for CO 2 capture from air with direct, Joule-heated regeneration. A techno-economic assessment with sensitivity analysis was conducted on a 100,000 TPY facility with 85% operating capacity. Through sorbent optimization and process design improvements, it is estimated that the cost of capture was reduced from $\$$349/tCO 2 to $\$$241/tCO 2 . The TEA projects further reductions to $165/tCO 2 through enhancements in CO 2 adsorption rate and sorbent capacity and reducing manufacturing and scale up risks. A life cycle analysis was conducted on the same 100,000 TPY facility and confirmed that the facility’s electricity demand drives its greenhouse gas impact. It was determined that electricity supplied through the current grid mix would result in net-positive CO 2 emissions and that achieving net-negative emissions is only possible by powering the system with renewable electricity or fossil fuel sources equipped with carbon capture and sequestration.

36 MATERIALS SCIENCE↗
DOE OSTI2024

Effect of Part Size, Displacement Rate, and Aging on Compressive Properties of Elastomeric Parts of Different Unit Cell Topologies Formed by Vat Photopolymerization Additive Manufacturing

Due to its ability to achieve geometric complexity at high resolution and low length scales, additive manufacturing (AM) has increasingly been used for fabricating cellular structures (e.g., foams and lattices) for a variety of applications. Specifically, elastomeric cellular structures offer tunability of compliance as well as energy absorption and dissipation characteristics. However, there are limited data available on compression properties for printed elastomeric cellular structures of different designs and testing parameters. In this work, the authors evaluate how unit cell topology, part size, the rate of compression, and aging affect the compressive response of polyurethane-based simple cubic, body-centered, and gyroid structures formed by vat photopolymerization AM. Finite element simulations incorporating hyperelastic and viscoelastic models were used to describe the data, and the simulated results compared well with the experimental data. Of the designs tested, only the parts with the body-centered unit cell exhibited differences in stress–strain responses at different part sizes. Of the compression rates tested, the highest displacement rate (1000 mm/min) often caused stiffer compressive behavior, indicating deviation from the quasi-static assumption and approaching the intermediate rate response. The cellular structures did not change in compression properties across five weeks of aging time, which is desirable for cushioning applications. This work advances knowledge on the structure–property relationships of printed elastomeric cellular materials, which will enable more predictable compressive properties that can be traced to specific unit cell designs.

36 MATERIALS SCIENCE↗
DOE OSTI2026

BIL High Speed Fuel Cell Stack Manufacturing

General Motors LLC (GM) was awarded a project to develop and implement technologies for manufacturing 20,000 units of Fuel Cell Stacks per year on two shifts per day basis. GM leveraged prior in-house expertise in designing the Fuel Cells, deploying the manufacturing process steps in the laboratory environment as well as the deployment in the industrial environment on a smaller scale. The project focus was to design, build, and deploy a manufacturing line consisting of an anode and cathode electrode processing, unitized electrode assembly, fuel cell stacking, compression, testing, and final assembly of the fuel cell stack. The project was terminated in the first budget period.

08 HYDROGEN↗
DOE OSTI2015

SU-E-T-595: Output Factor Calculation for a Uniform Scanning Proton Therapy System

Purpose: To develop an analytical model that predicts dose output factors for patient treatment fields in a uniform scanning proton therapy system. Methods: A model to predict output factors for patient specific treatment fields was produced based on the methods developed by Kooy et al. (2003). The Kooy model predicts the output factor based on the ratio of the entrance dose under calibration conditions to that for a given range and modulation corrected for the inverse square effect. Field specific output factors were plotted as a function of a single parameter r, where r = (Range-Modulation)/Modulation. The model targeted user range 1 sub-span 3 through user range 2 sup-span 2 of the IBA uniform scanning proton therapy system. The data set included points measured using the 10 cm and 18 cm snout sizes to eliminate stem effects on the monitor unit chambers. The data was fit using equation 15 from Kooy et al. (2003), and the resulting model was tested against measurements that were not included in the original data set. Results: For the range and sub span investigated, 120 data points were tested against the model prediction. The model predicted the output factor within 2% for 96% of the points tested and within 2.5% for 99% of the points tested. All points were within 3% of the predicted values. Conclusion: Monitor units for patient treatment fields with proton ranges that fall within the tested interval can be predicted using a model based on the methods developed at MGH. With further evaluation, it will be possible to model all user ranges and sub-spans of the IBA system. Further testing is also needed to predict output factors using a 25 cm snout which introduces variable scanning pattern sizes and stem effects on the monitor unit chambers.

61 RADIATION PROTECTION AND DOSIMETRY↗
DOE OSTI2017

Physical mechanisms for multiphase flow associated with hydrate formation

Many Arctic hydrate reservoirs such as those of the Prudhoe Bay and Kuparuk River area on the Alaska North Slope (ANS) are believed originally to be natural gas accumulations converted to hydrate accumulations after being placed in the gas hydrate stability zone (GHSZ) in response to ancient climate cooling. In this paper, the implications of a previously described mechanistic model for the transport of gaseous and aqueous phases are studied using a transient 1-D transport model during the conversion of a gas reservoir to a hydrate reservoir. The mechanistic model predicts/explains the vertical profile of hydrate saturation in “converted free gas” hydrate reservoirs. The initial gas phase saturation with depth is estimated from the profile of capillary entry pressure, which is estimated from grain size distributions measured in cores. The gas accumulation is assumed to be disconnected from its original source so that methane transport occurs only within it. As the base of the GHSZ descends through the sediment, hydrate forms within the GHSZ. The net volume reduction associated with hydrate formation creates a “sink” which drives flow of gaseous and aqueous phases to the hydrate formation zone. Mechanisms by which this fluid movement could have occurred are analyzed. Flow driven by saturation gradients plays a key role in creating reservoirs of large hydrate saturations, as observed in Mount Elbert stratigraphic test well in the Milne Point Unit of Alaska North Slope (ANS). Viscous-dominated pressure-driven flow of gaseous and aqueous phases cannot explain large hydrate saturations originated from large-saturation gas accumulations. The mode of hydrate formation for a wide range of rate of hydrate formation, the rate of descent of the base of GHSZ, and host sediment characteristics are analyzed and characterized based on dimensionless groups. The proposed transport model is also consistent with field data from hydrate-bearing sand units in Mount Elbert well. Finally, results show that not only the petrophysical properties of the host sediment but also the rate of hydrate formation and the rate of temperature cooling at the surface contribute greatly to the final hydrate saturation profiles.

58 GEOSCIENCES↗
DOE OSTI2015

Pre-conceptual Development and characterization of an extruded graphite composite fuel for the TREAT Reactor

In an effort to explore fuel systems that are more robust under accident scenarios, the DOE-NE has identified the need to resume transient testing. The Transient Reactor Test (TREAT) facility has been identified as the preferred option for the resumption of transient testing of nuclear fuel in the United States. In parallel, NNSA’s Global Threat Reduction Initiative (GTRI) Convert program is exploring the needs to replace the existing highly enriched uranium (HEU) core with low enriched uranium (LEU) core. In order to construct a new LEU core, materials and fabrication processes similar to those used in the initial core fabrication must be identified, developed and characterized. In this research, graphite matrix fuel blocks were extruded and materials properties of were measured. Initially the extrusion process followed the historic route; however, the project was expanded to explore methods to increase the graphite content of the fuel blocks and explore modern resins. Materials properties relevant to fuel performance including density, heat capacity and thermal diffusivity were measured. The relationship between process defects and materials properties will be discussed.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2017

On seasonal and semi-annual approach for flood frequency analysis

As a supplementary method to the conventional flood frequency analysis based on annual peak flows, we propose an approach in this paper to infer the flood frequency distribution on quarterly and semi-annual time scale, which are then converted to annual time scale to obtain the floods corresponding to return periods in unit of year. Two criteria for test of data independence, namely, minimum 7 and 15-day interval between two consecutive peak flows, are tested. The proposed approach was applied to Des Moines River at Fort Dodge, Iowa, USA using its 62 years of observation daily flows. The results show that the estimated floods for given return periods from quarter-annual data series are in general higher than the corresponding estimated floods from semi-annual data series, which is further larger than estimated floods from annual peak flows. In conclusion, the floods estimated from semi-annual data series agree well with the results of previous US Geological Survey study.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2017

Influence of tumor location on the intensity-modulated radiation therapy plan of helical tomotherapy

Given the design of the Helical TomoTherapy device, the patient's central axis is routinely aligned with the machine's rotational axis to prevent the patient's body from colliding with the machine walls. However, for treatment of tumors located away from the patient's central axis, this position may not be optimal as the adequate radiation dose may not reach the affected site. Our study aimed to investigate the influence of tumor location on dose quality and delivery efficiency of tomotherapy plans. A phantom and 15 patients were selected for this study. Two plans, A and B, were implemented for each case. In plan A, the patient's central axis was aligned with the machine's rotational axis, whereas in plan B, the center of the planning target volume (PTV) was aligned with the machine's rotational axis. Both plans were optimized with the same planning parameters, and the dose quality of the plans was evaluated using dosimetrics. The delivery efficiency was determined from delivery time and monitor units (MUs). A paired t-test or nonparametric Wilcoxon signed-rank test was performed for statistical comparison. In the phantom study, the median delivery times were 358 and 336 seconds for plans A and B, respectively, and this difference was significant (p = 0.005). In the patient study, the median delivery times were 348 and 317 seconds for plans A and B, respectively, and this difference was also significant (p = 0.001). The dose qualities of both plans for each patient were nearly identical. No significant differences were found in the conformal index, heterogeneity index, and mean dose delivered to normal tissue between the plans. Both phantom and patient studies showed that for normal-sized patients, the delivery time reduced as the distance between the PTV and the patient's central axis increased when the PTV center was aligned with the machine axis. In conclusion, aligning the PTV center with the machine's rotational axis by shifting the patient during tomotherapy reduces the delivery time without compromising the dose quality of intensity-modulated radiation therapy.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2023

Micro X-ray computed tomography examination of mini plate fuel with hot isostatic pressed aluminum cladding

In order to minimize proliferation risks and improve security of nuclear material, the United States high performance research and test reactors (USHPRR) program is tasked with converting nuclear reactors that are fueled with highly enriched uranium (HEU) fuels to operate with low-enriched uranium (LEU) nuclear fuels. One favorable LEU fuel configuration is plate fuel with a metallic uranium-molybdenum foil clad within an aluminum alloy (AA 6061). In this fuel, the aluminum cladding is bonded with a hot isostatic pressing (HIP) method to seal the cladding around the fuel meat. However, the HIP process parameters influence the cladding performance, as a defective or incomplete bond can cause a pathway for corrosion. Micro X-ray computed tomography (XCT), a nondestructive technique that provides volumetric imaging, can be applied to inspect fuel plate cladding at the engineering scale. In this work, XCT methodology was developed and successfully utilized to not only observe the bond line of unirradiated mini fuel plates, but to also identify subsurface abnormalities in the plates’ cladding. Importantly, in future work, this technique could be applied to fuel plates, pre- and post-irradiation, to quantify irradiation effects on cladding defects and bond line integrity.

36 MATERIALS SCIENCE↗