NNSS 3013 Staging and Enhanced Staging Program (ESP) Update
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3013 and ESP presentation for MIS↗
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ADVANCED RADIOLOGICAL MATERIAL STAGING: THE ENHANCED STAGING PROGRAM AT NNSS
The poster that will be presented at the PATRAM conference that is based on the previously submitted DOE/NV/03624--2192.
42 ENGINEERING↗
ADVANCED RADIOLOGICAL MATERIAL STAGING: THE ENHANCED STAGING PROGRAM AT NNSS
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Pulciano, Frank J. [Nevada National Security Site/↗
Controlling the operating speed of stages of an asynchronous pipeline
An asynchronous pipeline includes a first stage and one or more second stages. A controller provides control signals to the first stage to indicate a modification to an operating speed of the first stage. The modification is determined based on a comparison of a completion status of the first stage to one or more completion statuses of the one or more second stages. In some cases, the controller provides control signals indicating modifications to an operating voltage applied to the first stage and a drive strength of a buffer in the first stage. Modules can be used to determine the completion statuses of the first stage and the one or more second stages based on the monitored output signals generated by the stages, output signals from replica critical paths associated with the stages, or a lookup table that indicates estimated completion times.
97 MATHEMATICS AND COMPUTING↗
Controlling the operating speed of stages of an asynchronous pipeline
An asynchronous pipeline includes a first stage and one or more second stages. A controller provides control signals to the first stage to indicate a modification to an operating speed of the first stage. The modification is determined based on a comparison of a completion status of the first stage to one or more completion statuses of the one or more second stages. In some cases, the controller provides control signals indicating modifications to an operating voltage applied to the first stage and a drive strength of a buffer in the first stage. Modules can be used to determine the completion statuses of the first stage and the one or more second stages based on the monitored output signals generated by the stages, output signals from replica critical paths associated with the stages, or a lookup table that indicates estimated completion times.
Sadowski, Greg↗
Thermal performance of an absorption-assisted two-stage ejector air-to-water heat pump
In this work, a gas-fired air-to-water ejector heat pump (EHP) for domestic hot water production is proposed and analyzed thermodynamically. The COP of the EHP is improved by using binary fluids (HFE7500 and water), and the high backpressure in the primary ejector (first-stage) is actively controlled by either a second-stage ejector and/or a LiBr-H 2 O absorption subsystem. A thermodynamic model is established for analysis and performance evaluation. A case study shows the backpressure of the first-stage ejector is reduced by 53.5%, and the backpressure control using the second-stage ejector increases the system COP by 21.0% compared with that using LiBr-H 2 O absorption. Parametric studies are conducted to investigate the roles of the first-stage ejector, the second-stage ejector, and the LiBr-H 2 O absorption subsystem. The first-stage ejector plays a dominant role in the EHP system performance. The EHP’s heating COP can reach 2.0 with an entrainment ratio of 0.12 in the first-stage ejector. EHP performance can be improved with a high entrainment ratio and a low-temperature primary working fluid in the first-stage and second-stage ejectors, a low condensation temperature in the first-stage ejector, and a high generating temperature and a low concentration of the LiBr-H 2 O solution.
30 DIRECT ENERGY CONVERSION↗
Numerical Modeling of a Two-Stage Ocean Current Turbine
The Equinox Ocean Turbines (EQOT) current energy converter has a unique design with power generation in two small-diameter turbines attached to the tips of a large-diameter passive rotor. This configuration offers some key advantages for capturing ocean currents. With no centrally placed generator, almost no reaction torque is required at the nacelle of the main large-diameter rotor, and the small-diameter tip turbine generators operate at a higher speed and lower torque. The physics that determine the performance and loads on the turbine are also unique. The interactions of the flow field between the two stages and the general architecture of the system cannot be captured with traditional mid-fidelity modeling tools. For design iterations and large sets of load cases, it is important to have mid-fidelity models that can capture the important phenomenon with enough accuracy to identify global trends. This work uses a limited set of high-fidelity computational fluid dynamics (CFD) simulations to help inform the selection of and construction of a custom mid-fidelity model. Mid-fidelity modeling approaches were verified by comparing key turbine performance quantities to those found with the CFD model. Hydrodynamic interactions of the two-stage rotor were identified through high-fidelity CFD modeling. This highlighted the impact of the main rotor tip vortex and wake on the secondary rotor apparent inflow. This results in a relative flow rotation and sharp deficit, that change the optimal secondary rotor rotation speed and adds unsteadiness to the blade loading respectively. Multiple mid-fidelity approaches were evaluated for their ability to capture these effects. A simple approximation of the combined-stage performance based on single-stage BEM provides a reasonable rough prediction, especially near the peak TSR values, with some larger discrepancy at higher TSRs. Predicting the combined-stage performance based on single-stage CFD data improves this prediction across the TSR range. Although the combined-stage modeling in OLAF was not successful in this stage of the project, it showed promise as a mid-fidelity method, assuming the parameters can be tuned to account for the significant differences in time and length scales between the main and secondary rotors. This may be addressed through code changes in future work. A significant finding from the OLAF work was the agreement between the vortex core radius values found independently via a parameter space search and via CFD. The technique of using single-stage secondary rotor BEM, with a custom inflow taken from single-stage main rotor CFD or OLAF, provides an efficient method to capture one-way coupled flow interactions. This method provided generally good predictions of the impact of the flow rotation on the secondary rotor but struggled to accurately predict the peaks of the unsteady load progression. Future work could include some superposition of a tuned main rotor trailing edge viscous wake into the custom inflow to better predict this interaction.
16 TIDAL AND WAVE POWER↗
A Single-Stage Multilevel AC-DC Bidirectional Converter With Natural Grid Harmonic Elimination
Generally, AC-DC converters have an AC-DC stage followed by a DC-DC stage. In these two stage approaches, the AC-DC stage is hard-switched, whereas the DC-DC stage is soft-switched. Therefore, the devices in the AC-DC stage can be switched only at tens of kHz to avoid excessive switching losses, thus limiting the bandwidth of the current control loop. Hence, the control of these converters with distorted grid voltages requires multiple harmonic compensation loops or other complex control algorithms in order for the grid currents to comply with IEEE standards. By integrating both the stages, the devices in the AC-DC stage can also be soft-switched, thus facilitating higher switching frequency, and thereby higher current control bandwidth. This paper proposes an integrated multilevel bidirectional AC-DC converter with improved control bandwidth and disturbance rejection. It is shown experimentally that the high bandwidth current control loop of the converter can reject grid harmonic current disturbances, without the need for any compensation loops or complex control techniques, and comply with IEEE standards.
30 DIRECT ENERGY CONVERSION↗
Method and precision nanopositioning apparatus with compact vertical and horizontal linear nanopositioning flexure stages for implementing enhanced nanopositioning performance
An enhanced method and precision nanopositioning apparatus for implementing enhanced nanopositioning performance is provided. The nanopositioning apparatus includes a vertical linear nanopositioning flexure stage and a horizontal linear nanopositioning flexure stage. The vertical linear nanopositioning flexure stage includes a stage base, a symmetrically configured flexure linear guiding mechanism with precision motion enhancement structure, and a stage carriage. The horizontal linear nanopositioning flexure stage is mounted on the stage carriage of the vertical linear nanopositioning flexure stage, and includes a middle-bar relative position control mechanism to enhance the stiffness of a flexure linear guiding mechanism.
77 NANOSCIENCE AND NANOTECHNOLOGY↗
Biofluid-based staging of Alzheimer’s disease
Recently, conceptual systems for the in vivo staging of Alzheimer’s disease (AD) using fluid biomarkers have been suggested. Thus, it is important to assess whether available fluid biomarkers can successfully stage AD into clinically and biologically relevant categories. In the TRIAD cohort, we explored whether p-tau217, p-tau205 and NTA-tau (biomarkers of early, intermediate and late AD pathology, respectively) have potential for biofluid-based staging in cerebrospinal fluid (CSF; n = 219) and plasma (n = 150), and compared them in a paired CSF and plasma subset (n = 76). Our findings suggest a good concordance between biofluid staging and underlying pathology when classifying amyloid-positivity into three categories based on neurofibrillary pathology: minimal/non-existent (p-tau217 positive), early-to-intermediate (p-tau217 and p-tau205 positivity), and advanced tau tangle deposition (p-tau217, p-tau205 and NTA-tau positive), as indexed by tau-PET. Discordant cases accounted for 4.6% and 13.3% of all CSF and plasma measurements respectively (9.2% and 11.8% in paired samples). Notably, CSF- and plasma-based staging matched one another in 61.7% of the cases, while approximately 32% of the remaining participants were one to three biofluid stages higher in CSF as compared to plasma. Overall, these exploratory results suggest that biofluid staging of AD holds potential for offering valuable insights into underlying AD hallmarks and disease severity. However, its applicability beyond molecular characterization at research settings has yet to be demonstrated.
60 APPLIED LIFE SCIENCES↗
Optimal design of multi-stage vacuum membrane distillation and integration with supercritical water desalination for improved zero liquid discharge desalination
Herein this paper proposes a novel concept for the optimal design of multi-stage vacuum membrane distillation (VMD). Generally, a multi-stage VMD is designed with an equal temperature difference between each stage. However, such a design is energy inefficient and increases VMD area. An analytical methodology for calculating the optimal stage temperature is proposed. By selecting the optimal stage temperature, the energy efficiency and required membrane area can be potentially improved by 16% and 30%, respectively. The proposed concept applies to all heat sources, including latent, sensible, and waste heat. To illustrate the method, multi-stage VMD is integrated with the waste heat from a supercritical water desalination (SCWD) system to achieve zero liquid discharge. SCWD is an energy-intensive process, requires high-quality thermal heat (>450 °C), and exhibits high waste heat rejection. The integrated VMD-SCWD approach is approximately 50% more energy-efficient and 35% more cost-efficient than the standalone SCWD system. Compared to the commercially used brine concentrator and crystallizer, the multi-stage VMD-SCWD system is more energy efficient for feed concentrations >5%. VMD-SCWD system is 30% cheaper, due to less expensive membrane distillation modules compared to a brine concentrator. The proposed design concept can replace the brine concentrator and crystallizer as an improved alternative for a zero-liquid discharge desalination system.
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
Performance and flexibility improvements of Staged Pressurized Oxy-Combustion
Staged Pressurized Oxy-Combustion (SPOC) is a low-carbon coal combustion power technology being developed by Washington University in St. Louis (WUSTL). Oxy-combustion plants enable straightforward capture of carbon dioxide (CO 2 ) by removing most of the nitrogen in the combustion air prior to use, thereby burning fuel in near-pure oxygen instead of air, producing a flue gas containing primarily CO 2 and water. CO 2 capture at amounts > 90% is possible, often using cryogenic air separation. Oxy-combustion typically relies on flue gas recycle (FGR) to reduce the peak temperature and radiation that would otherwise occur in a fuel/oxygen only flame. SPOC reduces the peak temperatures of combustion by utilizing two or more pressurized boiler modules connected in series to produce fuel staging; hence, only a portion of the fuel is combusted in any given furnace module. This means that the thermal energy released at each stage can be captured and removed from the gases prior to subsequent stages, when more fuel is introduced. This allows the SPOC process to operate with minimal FGR, avoiding the associated efficiency losses and additional costs. Also, the process operates at an elevated gas-side pressure, reducing boiler size, enhancing heat transfer to achieve a compact boiler configuration as compared to an atmospheric-pressure boiler design, and allowing for recovery of the latent heat of the water from the flue gas at a temperature useful to the steam cycle. The resultant net efficiency of the system is over 3 percentage points greater than traditional atmospheric-pressure oxy-combustion, and 7 percentage points greater than the post combustion variant, representing a step-change improvement over first-generation capture technologies. To further develop the concept, WUSTL and the Electric Power Research Institute, Inc., organized a project with American Air Liquide, Inc., Doosan Babcock Limited, and the U.S. Department of Energy to investigate a practicable and workable boiler design. The team has identified the potential for enhanced process flexibility for controlling power generation over a wider load range than is normally available to conventional coal-fired power plants due to the staged nature of the heat release. With increasing intermittent renewable generator contribution, on-demand generators need to be highly flexible to participate in the future energy market, requiring extensive operation at reduced load. Conventional coal-fired steam generators typically face challenges in maintaining temperature control of the reheat steam and main steam at reduced loads. This results in inefficient operation, both in terms of the boiler efficiency and steam turbine heat rate. The results of this project show the SPOC process is capable of exceptional turndown, both on a stage basis and with the ability to bypass entire stages. Oxygen-supply flexibility was also investigated, as this is also a key consideration for the overall flexibility of the SPOC process given the operating constraints of conventional air separation units. A boiler design concept assessment was conducted and was focused on delivering compact and constructible design. The assessment checked appropriate tube operating metal temperatures at full load and at lower operating loads, balanced against the needs of efficient coal combustion, and the resultant slagging and ash environments. Combustion testing in the 100-kWth pressurized combustion test rig at WUSTL was carried out to validate the combustion, heat flux profiles and burnout at multiple loads. Combustion parameters investigated were flame stability, fuel burnout, ash composition, radiative heat flux, and temperature profiles. The results of these tests formed the basis of a full-scale boiler design that will encompass improvements in both efficiency and flexibility over conventional oxy-combustion processes. The air separation unit flexibility was investigated, and associated cost implications were addressed. Detailed economic assessment results for a 550 MWe net power block are also provided, allowing for a comparison against the baseline NETL oxy-combustion and post combustion capture cases.
20 FOSSIL-FUELED POWER PLANTS↗
A nomogram for prediction of stage III/IV gastric cancer outcome after surgery: A multicenter population‐based study
Abstract Most patients with gastric cancer (GC) are first diagnosed at stage III‐IV and surgery resection remains the primary therapeutic modality for these patients. However, clinical staging used for prediction of those patients provides limited information. We collected clinicopathological data and disease‐progression information from 508 patients with stage III‐IV GC at three Chinese hospitals and 1298 patients from the Surveillance, Epidemiology, and End Results database. Based on the stepwise multivariate regression model, we constructed a novel nomogram to predict overall survival (OS). The performance of discrimination for this model was measured using Harrell's concordance index (C‐index) and receiver‐operating characteristic curve (ROC), and was validated using calibration plots. Multivariate Cox regression analyses showed that tumor size, age at diagnosis, N stage, tumor grade, and distant metastases were outstanding independent prognostic factors of stage III‐IV GC. We developed a nomogram based on these five prognostic predictors. In the training set, the C‐index of the nomogram was 0.645 (95% CI: 0.611‐0.679), which was higher than that of the American Joint Committee on Cancer TNM system alone (sixth TNM: 0.544; seventh TNM: 0.575; eighth TNM: 0.568). Similar results were observed in validation cohort. Moreover, calibration blots demonstrated good consistency between the actual and predicted OS probabilities. According to the nomogram, GC individuals could be classified into three groups (low‐, middle‐, and high‐risk) ( P < .001). Our nomogram complements the current staging system for prediction of individual prognosis with stage III‐IV GC, and may be helpful for making individualized treatment decisions.
Gao, Zhiying↗
Multi-stage load partitioning in additively manufactured Al6061+TiC nanocomposite characterized by in-situ neutron diffraction
Metal matrix composites (MMCs), combining metal matrix and ceramic particles, exhibit high mechanical strength and stiffness compared to conventional metallic materials. During fusion-based additive manufacturing (AM), MMCs undergo a rapid heating and cooling thermal history, which affects the interfacial bonding, thermal misfit stress and mechanical load transfer behavior between the metal matrix and particles, thus impacting the bulk mechanical performance. Here, we investigate the deformation dynamics and phase-specific load transfer in fusion-based AMed Al6061 +TiC MMCs through in-situ neutron diffraction. By calculating the phase-specific lattice strains, a multi-stage load transfer and deformation behavior during uniaxial compression is revealed: (1) elastic deformation in Stage I for both phases; (2) sudden stress rebalance between two phases in Stage II, evidenced by a sudden decrease in Al lattice strain and increase in TiC; (3) active load carrying by both phases in Stage III, with both phases experiencing an increase in lattice strains. Further, the deformation mechanism of each stage is deducted by correlating the evolutions of the interphase stresses and peaks’ broadening and intensity of the Al matrix. The local plastic deformation of the Al matrix near the phase interface is triggered and leads to stress rebalancing in Stage II. The global plastic deformation subsequently propagates throughout the Al matrix in Stage III, and the composite is further hardened through both dislocation multiplication and load transfer. The findings offer valuable insights into deformation and load-sharing behavior in AMed MMCs.
36 MATERIALS SCIENCE↗
Multi-stage heat pump with two-phase injection for cold climate applications implementing natural refrigerants
Heat pump adoption in cold climates is limited by various technical challenges, including heat capacity degradation, compressor deterioration, and frost accumulation on the outdoor heat exchanger. Furthermore, wide-spread adoption of heat pumps with high global warming potential presents a possible environmental concern. Thus, we present a heat pump concept termed the “saturation cycle,” which uses numerous compression stages to improve energy efficiency and injects two-phase refrigerant between compression stages to dramatically reduce compressor discharge temperatures. Given the growing interest in heat pumps, there is a need for a straightforward framework for parametric evaluation of natural refrigerants in high-efficiency heat pump cycle architectures, like the saturation cycle, in adverse climates. This work develops a thermodynamic modeling framework and focuses on the application of natural refrigerants to explore the performance trends at extremely cold climates down to −25 °C. This study shows that a two-stage saturation cycle and four-stage saturation cycle can reduce the compressor discharge superheating by up to 51–57 % or 73–80 %, respectively, depending on the refrigerant. Furthermore, at −25 °C, a two-stage R-290 saturation cycle heat pump theoretically can use 25 % less power than a single-stage heat pump or can provide up to 59 % more heating capacity when using the same compressor power as the baseline single-stage heat pump. The exergetic parametric analyses show that two-phase refrigerant injection fundamentally improves the thermodynamic performance of the heat pump, reducing overall exergy destruction by 10 % compared to a vapor-injection heat pump, compared at −25 °C. Thus, the saturation cycle is a promising heat pump cycle architecture for cold climate applications due to its superior energy savings (or capacity improvement) and substantial de-superheating capabilities.
32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
Comparison of multi-stage air treatment process divided by the same temperature and enthalpy difference
The multi-stage air treatment system has been proposed recently, and lower grade chilled/hot water could be used and energy efficiency could be improved. However, it has not been studied which division method of air treatment processes has higher energy efficiency. In this study, the model to calculate the energy consumption of multi-stage air treatment process is introduced, and the effects of two division methods, i.e. multi-stage air treatment process divided by the same temperature difference (ST method) or same enthalpy difference (SE method) between inlet and outlet at each stage, under 9 different air inlet parameters in the 2-stage and 3-stage air treatment processes are analysed and compared. The results show that (1) the system energy consumption of the SE method is generally lower than that of the ST method; (2) there is generally a larger energy consumption reduction rate of SE method when the air relative humidity is 70% compared to relative humidity of 50% and 90%; (3) the difference between ST method and SE method is not great, so both methods can be used for the design of multi-stage treatment system although SE method is normally recommended.
Wang, Wentao↗
Design of Multi-Stage Solvent Extraction Process for Separation of Rare Earth Elements
Flowsheet design and stage determination for the separation of rare earth elements (REEs) using solvent extraction (SX) is a challenging task because of the chemical similarity of the REEs. Low separation factors between the elements and complex equilibrium chemistry provide unique challenges to designing an efficient flowsheet for the separation of elements. The multi-stage nature of the SX process adds further complexity, making the assessment of products for a proposed design and stage combination difficult. Therefore, to develop a SX flowsheet, it is essential to quantify the performance for various design and separation conditions. This paper attempts to address the challenge by utilizing an equilibrium and process modeling approach. Results from a bench-scale study performed on a 10 g/L rare earth salt mixture were used in studying the extraction/stripping behavior and developing equilibrium models. DEHPA with TBP as a phase modifier was used as an extractant, while hydrochloric acid was utilized as a stripping agent. The results obtained were used in developing extraction/stripping models, which were integrated into a process framework of a SX train in a Matlab/Simulink environment. The models were programmed as a function block routine and used for developing a flowsheet, which was simulated for differing separation and design conditions. To identify optimum stage combinations, a particle swarm optimization (PSO) routine was developed and implemented for each SX train. Recovery and purity of elements of interest were used as objective function criteria. The stage combination leading to the minimization of the objective function was used to identify the optimum stage combination for a series of SX trains to attempt a balance of purity and recovery. The models and optimization method were implemented to separate a feed mixture containing REEs, which indicated that 99.52 and 85.41 percent purity is achievable for Yttrium and Lanthanum separation using 8-12-3 and 10-3-5 stage combination for loading, scrubbing, and striping. The model also indicated difficult separability between neodymium, praseodymium, and cerium.
Srivastava, Vaibhav (ORCID:0000000212645987)↗
Single-stage transmitter for wireless power transfer
A single-stage transmitter for wireless power transfer is provided. The transmitter includes a rectifier stage and an inverter stage sharing a first phase leg. The rectifier stage further includes a rectifying leg including two diodes connected in series, and a boost inductor coupling the first phase leg and the rectifying leg to an input port. The inverter stage further includes a second phase leg. Each phase leg includes two switches connected in series. The first and second phase legs are coupled to an output port. A bus capacitor is coupled across the first phase, second phase, and rectifying legs. A controller is programmed to determine first and second parameters, based on an output power at the output port, to simultaneously control the rectifier stage and the inverter stage to maintain constant bus voltage and achieve high power factor and low total harmonic distortion at the input port.
Costinett, Daniel Jes↗