Operating Temperature Research Articles

Improving third harmonic generation performance by elevating the operation temperature of KDP and DKDP crystals

Improving third harmonic generation performance by elevating the operation temperature of KDP and DKDP crystals

Assessing the effect of temperature drop on a stable anaerobic fermentation for volatile fatty acids production

ABSTRACT Anaerobic fermentation (AF) processes are sensitive to temperature fluctuations, which can influence the microbial activity and overall metabolic performances. Anaerobic reactors can face unforeseen temperature control failures, leading to instabilities in the process. The present study investigated the effect of two short-term temperature perturbations (down to 20°C and 15°C) on AF of food wastes (FWs). While 20°C did not exhibit a negative impact on AF performance maintaining the bioconversion yields over 40%, the reactor subjected to 15°C presented an acidogenic limitation, which decreased the bioconversion yields (36.4 ± 1.8%). As a result, 2.2 ± 0.5 g/L of succinic acid was accumulated in the reactor, being identified as a temperature failure indicator. Once the conditions were reestablished (operation temperature of 25ºC), the metabolic redundancies identified in the reactors allowed the AFs recovery to initial fermentation yields. 20°C was further tested as operational temperature resulting in stable bioconversion yield similar to the Control Reactor (43.2 ± 0.3%). These results showed the feasibility of conducting AF under low temperatures, indicating the potential of this technology to increase the cost-effectiveness of AF at psychrophilic conditions.

Designing a Lithium-Ion Cell for Studies of a Single Degradation Mechanism Over a Wide Temperature Range

Abstract 18650-sized cylindrical cells containing single crystal Li[Ni0.6Mn0.4Co0.0]O2, Li[Ni0.6Mn0.35Co0.05]O2, and Li[Ni0.6Mn0.3Co0.1]O2 positive electrodes along with artificial graphite negative electrodes were constructed to be balanced at 4.05 V. These cells were designed so that they would have only the single degradation mode of lithium inventory loss due to the solid-electrolyte interphase layer growth. Cells were cycled both at C/3 and C/20 over a wide temperature range from 20 to 100°C in order to accelerate degradation processes at higher temperatures and more rapidly predict low-temperature behaviour. A low upper cutoff voltage of 4.0 V was selected to avoid electrolyte oxidation, and an electrolyte composition incorporating pure lithium bis(fluorosulfonyl)imide salt was chosen based on the temperature and voltage range of operation. A thorough post-cycling analysis was performed to verify the elimination of all degradation modes except inventory loss and minor impedance growth, which enabled the application of a simple square root time model to make accurate lifetime predictions. In addition, the capacity retention of these cells at elevated temperature is incredible, with the best cells retaining 87% capacity after 1400 C/3 cycles (one year) continuously at 85°C.

Experimental Operation of a Prototype 750C Advanced Chloride Molten Salt Bellows Valve

To achieve DOE 2030 SunShot targets that reduce the cost of liquid-based solar by an additional 40% to 70% beyond 2018 costs, a more reliable, highly manufacturable flow valve, capable of achieving operational temperatures of >700°C is required [1]. This paper investigates the development of an innovative high-temperature chloride molten salt valve, with operation up to 750°C. This valve is intended to be employed within Gen 3 CSP liquid-based thermal energy storage (TES) systems as well as Gen 4 modular salt reactor (MSR) technologies. This work details the general design and flow testing of a bellows-seal flow control valve (FCV). This design includes an integrated closed-loop thermal control system to ensure robust design for freeze-thaw cycles. The self-contained thermal management STM system, is unique in the salt valve industry since it is an integrated solution to provide a consistent, repeatable alternative to typical heat tracing. Additionally, the design includes the employment of a novel heat pipe valve stem to facilitate enhanced passive thermal management into the valve assembly. This valve stem heat pipe is designed to facilitate natural circulation within the bonnet to ensure robust operation, during both nominal and transient thermal operation. The valve body and trim will be designed using SS316H, consistent with Flowserve Corporation’s existing product base and is code qualified but will utilize clad material for materials corrosion, manufacturing cost reduction and compatibility to ensure design flexibility. A test campaign was performed in this investigation utilizing a novel 750°C ternary chloride (20%NaCl/40%MgCl2/40%KCl by mol. wt. %) molten salt flow loop. A discussion about the design and installation of the valves within this test bed is provided for this investigation. Valve test results from this study assessed Cv curves as well as multiple actuator cycles, under varying thermodynamic and operational mode conditions, which would be characteristic within a commercial molten salt facility. The results indicate nominal operation for the baseline design, though improved performance and reliability is expected with the full designed FCV.

Towards a More Efficient Design of High Temperature Concentrating Solar Power Plant With Cascaded Thermal Energy Storage

This work proposes a novel concentrating solar power (CSP) plant configuration aiming at a high operation temperature of 1000°C. The thermal energy storage system (TES) would be the focus of this research by modifying it and proposing four configurations to enhance the overall efficiency of high-temperature solar power towers. The objective is to identify the most thermodynamically efficient designs by analyzing the literature on the different components and comparing them to a reference base case of a conventional 100 MWe solar power tower plant (2-tank molten salt TES) operating at 565°C. The proposition consists of a Brayton/Rankine combined cycle with a double cascade TES. In the proposed cascade TES, the primary unit consists of a high-temperature air/ceramic packed-bed thermocline operating at 1000°C, while the secondary unit is a single molten salt tank used as sensible heat. The secondary TES is used as a heat sink during charge, improving efficiency and reducing the size of the air/ceramic-packed bed by extracting the thermocline out of the tank. Excess energy stored in the secondary TES is utilized for preheating during discharge. The methodology incorporates evaluating various combinations of solar block, TES, and power block integration. Combinations are selected from a comprehensive literature review. The study focuses on night-time operations. Further analysis of the cost-benefit of the designs would be required to compare the overall energy production and furthermore the LCOE.

Electrospun WO3/TiO2 Core–Shell Nanowires for Triethylamine Gas Sensing

In this work, WO3/TiO2 core–shell (C-S) nanowires (NWs) were successfully synthesized by the coaxial electrospinning method and subsequent high-temperature calcination treatment. After some microscopic structural characterizations, although the prepared WO3–TiO2 and TiO2–WO3 C-S NWs displayed quite different surface morphologies, both of the shell coatings were uniform and their typical shell thicknesses were extremely close, with mean values of 22 and 20 nm, respectively. In gas sensing tests, WO3/TiO2 C-S NWs exhibited good selectivity towards triethylamine (TEA) without significant interfering gases. Compared with bare WO3 and TiO2 NWs, WO3/TiO2 C-S NWs showed better gas sensing performance. Specifically, the optimal operating temperature and response of TiO2–WO3 C-S NWs to 100 ppm TEA were 130 °C and 106, which were reduced by 70 °C and increased by 5.73 times compared to bare WO3, respectively. Obviously, the C-S nanostructures contributed to improving the gas sensing performance of materials towards TEA. Finally, some hypothetical sensing mechanisms were proposed, which were expected to have important reference significance for the design of target products applied to TEA sensing.

Ultra-Sensitive Gas Sensor Based on CDs@ZnO

Ethylene glycol (EG) is a colorless and odorless organic compound, which is an important industrial raw material but harmful to the environment and human health. Thus, it is necessary to develop high-performance sensing materials to monitor EG gas. Herein, sea urchin-shaped ZnO was successfully synthesized by a hydrothermal method. Subsequently, a series of carbon dot (CD)-modified ZnO nanocomposites were successfully prepared using a simple mechanical grinding method. The prepared CDs@ZnO-1 sensor exhibits an excellent response to EG gas, with a response value of 1356.89 to 100 ppm EG at the optimal operating temperature (220 °C). After five cycles of detection, the sensor can still maintain a stable response. The enhanced sensing performance of EG can be attributed to rich oxygen vacancies that are generated on the surface of CDs@ZnO, and the heterojunction formed between p-type CDs and n-type ZnO. This study provides inspiration for the development of high-response semiconductor metal oxide sensors.

Effect of thermal stress on the life of DC link capacitors for smart grid

Thermal stress is an important factor affecting the life of a DC link capacitor (DCLC). However, relevant studies on thermal stress mechanism directly influencing the lifetime of the capacitor are rarely reported. In this paper, the heat setting and thermal stress of DCLC has been analyzed, and the relevant experimental platforms have been developed to evaluate the breakdown strength of DCLC at two heat setting temperatures (HSTs). Simultaneously, the life aging analysis of DCLC at different HSTs and the life aging tests at various temperatures were also executed to attain insights into the influence of thermal stress on the lifetime of DCLC. The results showed that the stress caused by heat setting and operating temperature influenced the breakdown voltage capability and the lifetime of DCLC. With an increase in HST by 5 °C, a step-increase in the withstand voltage capability of DCLC from 7,000 V to 7,200 V was observed that demonstrated an enhancement of 2.86% in the breakdown strength performance. Correspondingly, the lifetime of DCLC with a capacitance change rate of -3% enhanced from 1,500 h to 1,700 h. However, severe deterioration in the life span of DCLC from 4,200 h to 500 h was observed with an increasing operating temperature from 55 °C to 85 °C, respectively. The lifetime could be enhanced by increasing the HST as well as reducing the operating temperature. The presented results could be termed a harbinger for industrial production of high-performance DCLC with enhanced lifetime that augers well for high-power applications.

Habitat conservation enhances the resilience of the lizard Liolaemus cuyumhue to high summer temperatures

Habitat degradation from human activities affects essential microhabitats, threatening ecological processes like foraging, mating, locomotion, predator evasion, and competition among reptiles. We assessed how microhabitat selection and body temperature of the endangered lizard Liolaemus cuyumhue respond to differences in vegetation composition and thermal conditions between a disturbed site and an undisturbed site impacted by oil and gas activities in Argentina. During five expeditions between September 2022 and March 2023, we searched for L. cuyumhue and collected data on body temperature, substrate and air temperatures, body mass, snout-vent length, sex, and habitat characteristics. We also measured operative temperatures and assessed vegetation cover and microhabitat availability at each site. Our results showed significant differences in microhabitat characteristics and selection between sites. The undisturbed site had higher vegetation and lower operative temperatures, while the disturbed site had higher temperatures and lower vegetation, especially in summer. Lizards at the disturbed site showed higher body temperatures, suggesting stressful thermal conditions, and preferred microhabitats with lower bare ground cover. Capturing lizards in the disturbed site required more effort than in the undisturbed site. This study emphasizes the impact of habitat disturbance on the thermal environment and behavior of L. cuyumhue. Conservation efforts should prioritize maintaining and restoring vegetation to support the species’ thermoregulation needs, especially under global warming.

Enhancing electrochemical properties of PNb9O25 anodes at elevated temperature via surface modification by nitrogen-doped carbon

Improving the performance of electrode materials is a crucial step for enhancing the intrinsic safety of batteries, especially during high operating temperature and rapid charge/discharge processes. The aggravation of side reactions caused by electro-thermal behaviors especially at high operating temperature is the main factor causing the instability of surface structure. In this work, we focus on the titanium-free, coarse-grained PNb9O25 (PNO) anode and enhance its electrochemical performance at an elevated temperature of 45 °C using a nitrogen-doped carbon (N-C) surface modification strategy. The homogeneous N-C passivation layer provides favorable electronic conductivity and fast Li+ diffusion kinetics, significantly reducing chemical reactivity and improving the interfacial charge transfer capability. As a result, PNO@N-C demonstrates exceptional high-rate capacity retention (249 mAh g–1 at 0.1 A g–1 and 173 mAh g–1 at 6 A g–1 under 45 °C) and superior cycling stability, maintaining a high capacity of 147 mAh g–1 after 1000 rapid charging cycles at a current density of 4 A g–1 (∼20 C, 45 °C). This approach provides a practical strategy for further development of electrode materials for high-rate lithium-ion batteries operating at high temperatures.

Synthesis of Polyether Ester Plasticizer and Its Application Performance in Hydrogenated Nitrile Butadiene Rubber

ABSTRACTFour polyether ester plasticizers containing both ester groups and ether bonds were synthesized using 1,4‐butanediol, adipic acid, and alkyl ether alcohols as raw materials. By varying the type of end‐capping alcohol ether, the following plasticizers were prepared: poly (butylene adipate dibutyl ether) (PBADBE), poly (butylene adipate butyl ether) (PBABE), poly (butylene adipate dimethyl ether) (PBADME), and poly (butylene adipate methyl ether) (PBAME). These plasticizers were characterized by Fourier transform infrared (FTIR) spectroscopy, proton nuclear magnetic resonance spectroscopy (1H‐NMR), and thermogravimetric (TG) analysis. Furthermore, their differences in cold resistance, heat resistance, and physical‐mechanical properties in hydrogenated nitrile‐butadiene rubber (HNBR) were investigated. The results showed that among the rubber compounds containing the four polyether‐ester plasticizers, the compound with PBADME demonstrated superior heat resistance and low‐temperature performance. Specifically, the PBADME‐containing compound exhibited a TR10 temperature of −39.9°C and a brittleness temperature of −54°C. This significantly broadened the operating temperature range of the plasticizer, making it suitable for applications requiring both high‐temperature and low‐temperature performance.

Wide-temperature and high-voltage Li||LiCoO2 cells enabled by a nonflammable partially-fluorinated electrolyte with fine-tuning solvation structure

Efficient, safe, and reliable energy output from high-energy-density lithium metal batteries (LMBs) at all climates is crucial for portable electronic devices operating in complex environments. The performance of corresponding cathodes and lithium (Li) metal anodes, however, faces significant challenges under such demanding conditions. Herein, a nonflammable electrolyte for high-voltage Li||LCO cells has been designed, including partially-fluorinated ethyl 4,4,4-trifluorobutyrate (ETFB) as the key solvent, guided by theoretical calculations. With this ETFB-based electrolyte, Li||LCO cells exhibit enhanced reversible capacities and superior capacity retention at an elevated charge voltage of 4.5 V and a wide operating temperature range spanning from −60 °C to 70 °C. The cells achieve 67.1% discharge capacity at −60 °C, relative to room temperature capacity, and 85.9% 100th-cycle retention at 70 °C. The outstanding properties are attributed to the LiF-rich interphases formed in the ETFB-based electrolyte with a fine-tuned solvation structure, in which the coordination environment in the vicinity of Li+ cations and the distance between anion and solvents are subtly adjusted by introducing ETFB. This solvation structure has been mutually elucidated through joint spectra characterizations and atomistic simulations. This work presents a new strategy for the design of electrolytes to achieve all-climate reliable and safe application of LMBs.

Real-Time Temperature Monitoring VHMS Dashboard Development to Reduce Component Unscheduled Breakdown

The coal mining industry relies on heavy equipment such as excavators and bulldozers and their efficiencies are critical for the productivity. This paper addresses the issue of unscheduled breakdowns due to high operational temperatures which impacts productivity, equipment availability and maintenance costs. The existing Vehicle Health Monitoring System (VHMS) from Komatsu Original Manufacturing lacks of real-time data for coolant temperature. The data recording is only every 20 hours and data reporting to the monitoring system is transferred daily. This lack of data is leading to unable for identifying the causes of problems. This study proposes a real-time temperature monitoring dashboard for the VHMS to track and manage Komatsu equipment temperature limits and to upgrade the existing system to record temperature data in every second instead of every 20 hours. This fine data collection provides enough information for a comprehensive analysis of machine conditions. This allows for quick identification of abnormal temperature trends, leading to timely maintenance and failures prevention. The new dashboard system provides immediate access to detailed temperature data, facilitating prompt decision-making in maintenance process. It also involves setting new temperature limits to prevent overheating and reduce unscheduled component breakdown from 25% in 2019 to 0% in 2023 and 2024. Implementing a real-time temperature monitoring dashboard is expected to improve equipment availability, reduce breakdowns, optimize maintenance schedules and lower operational costs in the coal mining industry.

In Situ Formation of a Melt‐Solid Interface Toward Stable Oxygen Reduction in Protonic Ceramic Fuel Cells

AbstractProtonic ceramic fuel cells (PCFCs) are one of the promising routes to generate power efficiently from various fuels at economically viable temperatures (500–700 °C) due to the use of fast proton conducting oxides as electrolytes. However, the power density and durability of the PCFCs are still limited by their cathodes made from solid metal oxides, which are challenging to address the sluggish oxygen reduction reaction and susceptibility to CO2 simultaneously. Here, an alternative approach is reported to address this challenge by developing a new melt‐solid interface through the in situ alkali metal surface segregation and consecutive eutectic formation at perovskite oxide surface at PCFC operating temperatures. This new approach in cathode engineering is successfully demonstrated over lithium and sodium co‐doped BaCo0.4Fe0.4Zr0.1Y0.1O3‐δ perovskite as the model material. These experimental results unveil that the unique in situ formed melt‐solid surface stabilizes the catalytically active phase in bulk and promotes catalytically active sites at surface. The novel engineered melt‐solid interface enhances the stability of the cathode against poisoning in 10% CO2 by a factor of 1.5 in a symmetrical cell configuration and by a factor of more than two in PCFC single cells.

Impact of water based nanofluids in heat exchanger type active solar PV cooling systems: A comparative CFD analysis

Solar photovoltaic technology is a fast growing form of renewable energy with many positive factors such as low cost, environmental friendliness, energy independence, etc. But, one of the major drawbacks of solar photovoltaic technology is the less efficiency compared to other forms of renewable energy technologies. There are many factors affecting the efficiency of a solar PV system such as temperature, solar irradiance, material quality, reflection losses, cell design etc. Researchers are focusing on different aspects to control the above factors to improve the efficiency of solar PV systems. Solar photovoltaic cooling system is one such solution which can be used to control the operating temperature of solar photovoltaic cells. The most common coolant used in these systems is water due to its superior thermo physical properties. In this research we are focusing on improvement of the thermophysical properties of water using nanotechnology. This article presents a CFD (Computational Fluid Dynamics) analysis conducted for a heat exchanger type solar PV cooling system integrated with a solar photovoltaic panel for water based nanofluids mainly focusing on three metal oxide nanoparticles Al2O3, CuO, and TiO2. Initially the heat exchanger model was developed using Solid Edge 2022 software and the thermo physical properties were simulated using Ansys 2019 software for different water based nanofluids. The obtained results were analyzed comparatively with the performance of water as a coolant in the same heat exchanger system. The results conclude that metal oxide/water based nanofluids have comparatively better thermal properties than water and can be suggested as possible alternatives for water in closed loop heat exchanger applications.

A Review on Advancements in Solid‐State Hydrogen Storage: The Role of Porous Hollow Carbon Nanospheres

AbstractThe hydrogen economy provides an alternative energy source that can be adopted for a long period. One of its key components is an efficient storage system, which has become a topic of significant research interest to meet the energy goals set by the US Department of Energy (DOE). The US DOE outlines the criteria for suitable hydrogen storage materials, which include cost‐effectiveness (specifically $300/kg H2 by 2025 and ultimately $266/kg H2), moderate operation temperatures (233–358 K), high storage capacity (5.5 wt% 40 g/L 2025, 11 wt%, 79 g/L ultimate), efficient adsorption/desorption cycles, as well as long lifetime operation (1500 cycles). Nanomaterials, particularly porous hollow carbon nanospheres (PHCNs), have attracted considerable attention due to their high storage capacity and unique characteristics, such as high surface area, tunable pore size, and superior kinetics. As a result, PHCNs may help to increase the hydrogen storage capacity of the solid‐state hydrogen storage systems. This paper offered an in‐depth analysis of the applications of PHCNs in hydrogen storage, comprising their synthesis, characterization methods, infiltration techniques, and the recent progress on the catalytic effects of the materials concerning hydrogen storage. The review concluded with a suggestion for future studies to increase the storage capacity of PHCNs in solid‐state hydrogen storage systems comprehensively, as it represents a pivotal step toward a hydrogen‐based economy, promoting energy security, and carbon‐neutral energy cycles.

Thermostable terahertz metasurface enabled by graphene assembly film for plasmon-induced transparency

With the increasing demand on high-density integration and better performance of micro-nano optoelectronic devices, the operation temperatures are expected to significantly increase under some extreme conditions, posing a risk of degradation to metal-based micro-/nano-structured metasurfaces due to their low tolerance to high temperature. Therefore, it is urgent to find new materials with high-conductivity and excellent high-temperature resistance to replace traditional micro-nano metal structures. Herein, we have proposed and fabricated a thermally stable graphene assembly film (GAF), which is calcined at ultra-high temperature (~ 3000 ℃) during the reduction of graphite oxide (GO). Compared with micro-nano metals that usually degrade at around 550 ℃, the proposed GAF maintains a high extent of stability at an extremely high temperature up to 900 ℃. In addition, to make GAF a prime candidate to replace micro-nano metals, we have modified its fabrication process for improving its conductivity to 1.3 × 106 S/m, which is quite close to metals. Thus, micro-nano optoelectronic devices could retain high efficiency even when GAF replaces the crucial micro-nano metals. To verify the thermostability of optoelectronic devices composed of GAF, we have compared the high-temperature resistance performance of two structures capable of achieving plasmon-induced transparency (PIT) at the THz region, one using micro-nano metals (Aluminum) and the other GAF. The Al metasurface displayed a near-complete loss of PIT effects after a high-temperature treatment, while GAF could remain excellent PIT properties at above 900 ℃, thus enable to fulfil its optimum performance. Overall, the proposed thermostable metasurface provides new pathway for the construction of thermostable optoelectronic devices that can operate under ultra-high temperature scenario.

Colloidal Quantum-Dot Heterojunction Imagers for Room-Temperature Thermal Imaging.

Room-temperature operation or high-operation temperature (HOT) is essential for mid-wave infrared (MWIR) optoelectronics devices providing low-cost and compact systems for numerous applications. Colloidal quantum dots (CQDs) have emerged as a rising candidate to enable photodetectors to operate at HOT or room temperature and develop the next-generation infrared focal plane array (FPA) imagers. Here, band-engineered heterojunctions are demonstrated to suppress dark current with well-passivated mercury telluride (HgTe) CQDs enabling room-temperature MWIR imaging by single-pixel scanning and 640×512 FPA sensitive thermal imaging above 250K. As a result, the room-temperature detectivity reaches as high as 1.26×1010 Jones, and the noise equivalent temperature difference (NETD) is as good as 25mK up to 200K.

Operation of a Compression Ignition Engine at Idling Load Under Simulated Cold Weather Conditions

Abstract Heavy-duty compression ignition (CI) engines can be subject to long periods of idling during their duty cycles. In colder climates, getting the engine and exhaust aftertreatment (EAT) system to ideal operating temperatures can be challenging under such idling and low load conditions. This may lead to high emissions of criteria pollutants especially nitrogen oxides (NOx). Increasing the engine load and idling speed may help mitigate NOx emissions but typically leads to higher greenhouse gas emissions. Therefore, the objective of this study is to evaluate the performance of a heavy-duty CI engine operating at various idling conditions and determine suitability for exhaust aftertreatment system operation. Tests are conducted on a heavy-duty single cylinder CI research engine fueled with diesel. As per the United States' (U.S.) Code of Federal Regulations (CFR), CI engines can be certified for the optional Clean Idle NOx emission standard. A corresponding two-mode Clean Idle Test (CIT) is specified in CFR which requires the engine to be operating in fully warmed-up condition at two engine speeds. Steady-state tests are conducted at these two engine speeds of 650 and 1100 rpm, and cold weather operation is simulated by operating the engine at suboptimal coolant, lubricant, and intake air temperatures. The steady-state tests are used to determine suitable diesel injection timing for performing the CIT under standard and simulated cold weather conditions. At the lowest load and 650 rpm idling speed, use of multiple injections and exhaust gas recirculation (EGR) are insufficient for raising the exhaust gas temperature above 200 °C. A combination of higher load, EGR, and 1100 rpm idling speed can create conditions for light-off selective catalytic reduction (LO-SCR) operation at the expense of higher fuel consumption. The modified CIT results show that the optional Clean Idle NOx emission standards can be met with the use of EGR at both test modes. The mode 2 conditions at 1100 rpm may allow LO-SCR activation as well. There are also distinct differences between results under fully and partially warmed-up conditions.

Calibration of RAFM Micromechanical Model for Creep Using Bayesian Optimization for Functional Output

Abstract A Bayesian optimization procedure is presented for calibrating a multimechanism micromechanical model for creep to experimental data of F82H steel. Reduced activation ferritic martensitic (RAFM) steels based on Fe(8–9)%Cr are the most promising candidates for some fusion reactor structures. Although there are indications that RAFM steel could be viable for fusion applications at temperatures up to 600∘C, the maximum operating temperature will be determined by the creep properties of the structural material and the breeder material compatibility with the structural material. Due to the relative paucity of available creep data on F82H steel compared to other alloys such as Grade 91 steel, micromechanical models are sought for simulating creep based on relevant deformation mechanisms. As a point of departure, this work recalibrates a model form that was previously proposed for Grade 91 steel to match creep curves for F82H steel. Due to the large number of parameters (9) and cost of the nonlinear simulations, an automated approach for tuning the parameters is pursued using a recently developed Bayesian optimization for functional output (BOFO) framework (Huang et al., 2021, “Bayesian optimization of functional output in inverse problems,” Optim. Eng., 22, pp. 2553–2574). Incorporating extensions such as batch sequencing and weighted experimental load cases into BOFO, a reasonably small error between experimental and simulated creep curves at two load levels is achieved in a reasonable number of iterations. Validation with an additional creep curve provides confidence in the fitted parameters obtained from the automated calibration procedure to describe the creep behavior of F82H steel.