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NASA NTRS2019

Lipid Decontamination Procedures for Life Detection Missions

Molecular biosignatures are key targets for current, proposed, and future life detection missions. With the high accuracy and low limit of detection (LOD) that new and future instruments will require, decontamination of life detection hardware is necessary to prevent false positives. Lipids are a molecular biosignature of interest, as they are ubiquitous to all life as we know it, can survive unaltered in the geologic record for longer than any other biomolecule (i.e. billions of years), and form through both biotic and abiotic processes. Lipids display origin-diagnostic molecular patterns that can reveal biotic or abiotic synthesis, so finding them and ascertaining their molecular features is important for potentially detecting evidence of life elsewhere. Traditional methods of decontamination, or contamination control (CC), primarily clean hardware through fabrication in sterile (cleanroom) environments, killing microbes, and removing/flushing contaminants off instrument and spacecraft components. However, research suggests that some standard cleaning methods are either unlikely to remove lipid contaminants or are incompatible with life detection instrument materials. To solve this problem, I propose to find, test, and verify a decontamination method that thoroughly cleans instruments by destroying lipid molecules, but is simultaneously compatible with major materials used in these instruments. I will study the effects of traditional CC methods (including Dry Heat Microbial Reduction and Vapor phase Hydrogen Peroxide) and experimental CC methods (Electron Beam Irradiation) on lipid molecules for application to life detection instrumentation. I will then develop a CC plan for a novel lipid detector (ExCALiBR, Extractor for Chemical Analysis of Lipid Biomarkers in Regolith) searching for lipids in either soil or icy world scenarios. This plan will uphold planetary protection regulation requirements and validate experimental analyses of in-situ life detection tests.

Decontamination↗
NASA NTRS2019

Rewet Temperature Correlations for Liquid-Nitrogen Boiling Pipe Flows Across Varying Flow Conditions and Orientations

In many convective liquid-vapor phase change heat transfer engineering applications, cryogenic fluids are widely used in industrial processes, spacecraft and cryosurgery systems, and so on. For example, cryogens are usually used as liquid fuels such as liquid hydrogen and oxygen in the rocket industry, liquid nitrogen (LN2) and helium are frequently used to cool superconducting magnetic device for medical applications. In these systems, proper transport, handling, and storage of cryogenic fluids are of extreme importance. Among all the cryogenic transport processes performed in room temperatures, quenching, also termed chilldown, is a unavoidable initial, transient phase-change heat transfer process that brings the system down to the cryogenic condition. The Leidenfrost temperature or rewet temperature that signals the end of film boiling is practically considered the completion point of a quenching process. Therefore, rewet temperature has been considered the most important parameter for the engineering design of cryogenic thermal management systems. As most of the previous correlations for predicting the Leidenfrost temperature and the rewet temperature have been basically developed for water, they are shown to disagree with recent liquid nitrogen pipe chilldown experiments in upward and downward flow directions over a wide range of flow rates, pressures, and degrees of inlet subcooling. In addition to a complete review of the literature, two new correlations are presented in this work, one based on bubble growth and another based on the theoretical maximum limit of superheat. Each correlation performs well over the entire data set.

liquid nitrogen↗
NASA NTRS2019

MARCI-observed clouds in the Hellas Basin during northern hemisphere summer on Mars: Interpretation with the NASA/Ames Legacy Mars Global Climate Model

We present a study that is motivated by a population of water ice clouds in the Hellas Basin that has been observed by the MARs Color Imager (MARCI) instrument on the Mars Reconnaissance Orbiter (MRO) to persist throughout the majority of Northern Hemisphere (NH) summer. Although water ice clouds are present in Hellas at very low opacities throughout NH spring, they noticeably thicken after L(sub s) 60° and continue to do so until their peak optical thickness is attained at L(sub s) ~120°. They dissipate rapidly from L(sub s) 120° to 150°, and by L(sub s) 150°, the only clouds in Hellas are on the southern side of the basin and are indistinguishable from the polar hood clouds. We use the NASA/Ames Legacy Mars Global Climate Model (GCM), which is supported by the Agency’s Mars Climate Modeling Center, to investigate the dynamical and microphysical mechanisms that control the formation and evolution of Hellas water ice clouds. We show that water is transported from the North Polar Residual Cap (NPRC) southward across the equator and into the Hellas region. Water vapor is confined down low by cloud formation in the aphelion cloud belt, thus limiting the effectiveness of transport by the zonal mean overturning circulation (i.e., the Hadley cell). Thus, contrary to the commonly held conceptual understanding that the Hadley cell controls cross-equatorial water transport during this season, we show that the southward transport of water is done primarily in the vapor phase by stationary eddies at nearly all latitudes, including across the equator. Clouds form near the surface in the basin as moist air mixes with cold polar air on the western side of Hellas and are subsequently transported clockwise around the north side of the basin by the low-level cyclonic circulation. The simulated Hellas clouds have small particle sizes (~3–5 μm), are very low, and exist as long as the NPRC is exposed.

M. A. Kahre↗
NASA NTRSDate not supplied

Flow Boiling in Microgap Coolers - Suborbital Flight Results

Flow Boiling in Microgap Coolers (FBMC) is a thermal management technique that provides embedded, on-site heat removal for power dense electronic components and systems. The dielectric coolant undergoes liquid-to-vapor phase change as it passes through channels integrated within or between devices. By facilitating direct contact between the coolant and heat-generating devices and relying on phase change, the system provides tight temperature control, hot spot mitigation, very high heat transfer coefficients, and low pumping power. Ground tests demonstrated removal of high heat fluxes (up to 500 kW/m2), very high coefficients of performance (up to 40 W of heat transferred per W of pumping power), and consistent performance across five evaporator orientations under the appropriate conditions. As a follow-on study and to better assess the role of gravity on such two-phase systems, the FBMC payload was developed and flown twice aboard the Blue Origin New Shepard space vehicle in January and May 2019. Each flight exposed the payload to weightlessness (150 seconds below 0.01 g) and shorter periods of high-g during ascent (up to 3 g) and descent (up to 5 g). The flow boiling performance was consistent independent of the acceleration levels, which provides confidence that such systems will provide consistent performance when tested on the ground, orbiting or traveling through weightlessness, and operating on the surface of the Moon, Mars, and other planetary bodies. Details of the flight results, payload development, flight environment, and planned future testing will be presented.

Flow boiling↗
NASA NTRSDate not supplied

Dew Point Simulation and Analysis of the Heat Melt Compactor Gas Effluent

The effluent gases and water vapor of the Trash Compaction and Processing System (TCPS) can be vented through the Vacuum Exhaust System (VES) if requirements are met. One of the constraints in this venting scenario is the dew point of the exhaust gases disposed into the VES must be less than 15.5 °C. With simulations using Aspen Plus and the effluent gas sample results of the Heat Melt Compactor (HMC), flash calculations were conducted in the modeling study to calculate the feed temperature and dew point at fixed pressures. Saturated vapor curves were produced and provided a preliminary result on optimal feed conditions that satisfy the dew point and vapor-phase only requirements after flashing across the throttle valve towards the VES.

trash↗
NASA NTRS2004

Self-assembled InAsSb quantum dots on (001) InP substrates

Self-assembled InAsSb quantum dots (QD) on (001) InP substrates have been grown using metalorganic vapor phase epitaxy. The dot density and size are found to be strongly dependent on the presence of arsine. Direct deposition of InSb on InP and GaSb substrates formed large islands of InSb with low density of less than 53109/cm², however, InAsSb QDs of density as high as 4 X10¹º/cm² could be self-assembled by alternating group III and group V precursors, and high density almost pure InSb QDs were achieved on In0.53Ga0.47As/InP. The formation of high density InAsSb QDs is a result of a local nonequilibrium process and a reduction in mobility of In adatoms on the growth surface due to the presence of arsenic atoms, and in the case of high density almost pure InSb QDs on InGaAs/InP, the InAs interface layer is believed to be responsible. Photoluminescence shows that InSb QDs emit light at room temperature in the range of 1.7–2.2µm.

Uhl, David↗
NASA NTRSDate not supplied

Crystal Growth in the SUBSA furnace in MSG: 2002 to 2022

In 2002, the investigation “Solidification Using a Baffle In Sealed Ampoules (SUBSA)” was the first investigation to utilize the Microgravity Science Glovebox (MSG) Facility on the International Space Station (ISS). The SUBSA furnace was designed for growth of indium antimonide. It features a transparent section, which allows a side view of the melt, the solid-liquid (SL) interface and the growing crystal. In 2002, four Te-doped and three Zn-doped InSb crystals were grown in microgravity. Subsequently, the SUBSA furnace was used in several materials science investigations, including growing the radiation detector materials, InI and Cs2LiYCl6:Ce from the melt and vapor phase (2017 to 2019) and “Brazing of Aluminum alloys in Space (BRAINS)”. A review of the SUBSA furnace features and parameters will be presented, including the design of the growth ampoules, charge preparation, and the procedures used to grow InSb (in 2002) and InI (in 2019).

Aleksandar Ostrogorsky↗
NASA NTRSDate not supplied

Simulation-Aided Design and Interpretation of Results of Microgravity-Based Solidification Experiments

The preparation and interpretation of microgravity experiments conducted on the International Space Station (ISS) can be challenging because of the remote location of the equipment. Although a “ground unit” is typically available on Earth, it is not located in the laboratory of the principal investigator. Furthermore, test experiments in the ground unit cannot fully duplicate heat transfer conditions of the weightless environment, and thus be a reliable reference for experiment design. Under such conditions, numerical simulations are a valuable tool both for preparing the experiments and interpreting the results obtained under terrestrial and micro-gravity conditions. In this work, we developed a detailed 3D model of the “SUBSA” furnace located at the ISS, and demonstrate its use in our present investigation which includes melt growth and vapor growth of InI crystals on the ISS. In 2002, the SUBSA furnace was designed and built for the growth of InSb crystals in the Microgravity Science Glovebox (MSG) at the ISS. The SUBSA furnace features a transparent section without heating elements, where the axial temperature gradient is high. In our present investigation, we have used the same furnace to grow four InI crystals from the melt, and two InI crystals from the vapor phase (2018-2021). InI crystals have ~20 times lower thermal conductivity than InSb crystals. As a result, during melt growth, the InI crystals were exposed to extremely high temperature gradients. To reduce the axial temperature gradient, we added external jackets made from high thermal conductivity material to the growth ampoules. The SUBSA furnace could not be modeled as asymmetric because of its rectangular shape and right-angled transparent section, which contains a convoluted geometry. The rectangular shape of the transparent section further complicates modelling of radiative heat transfer, which dominates in the zone. At present, numerical simulations are being conducted to resolve an apparent discrepancy between the readings of the 5 thermocouples located in the SUBSA furnace, and the observed position of the solid and molten material. The 3D simulation will be presented, along with the calibration and growth experiment results conducted in microgravity and in the SUBSA ground unit. The developed model should be useful for upcoming microgravity investigations planned to be conducted in the SUBSA facility.

V Riabov↗
NASA NTRS2022

Characterization of Lunar Polar Volatiles for Curation and ISRU - Executive Summary

The goal of this project is to support lunar exploration by simulating and characterizing ice and volatile-rich materials expected to be found at the lunar poles. These materials are highly sensitive to heating, which could significantly alter their composition and prevent scientific studies on lunar samples. During FY19, we obtained materials for and designed a simulated lunar environment, within which volatile-rich simulant could be made. We also refined the procedure for moderate-fidelity lunar simulants at cryogenic temperatures. In FY20, we completed our test setup, and we can now reach cryogenic temperatures and near-lunar pressures with active compositional monitoring of volatiles in the vapor phase. For FY21, we: 1) progressed towards developing sample storage temperature requirements for volatile-rich samples by completing storage testing, along with materials testing for Artemis geologic sampling, 2) obtained instrumentation for solid sample monitoring to characterize solid species, and 3) progressed towards water extraction testing for ISRU. Our test results will directly feed into Artemis science requirements, hardware designs for sample return, vehicle requirements (HLS, Gateway, Orion), and operations planning for lunar exploration activities.

Julie L Mitchell↗
NASA NTRSDate not supplied

Crystal Growth in the SUBSA furnace at the International Space Station (ISS)

In 2002, our investigation Solidification Using a Baffle In Sealed Ampoules (SUBSA) was the first investigation to utilize the Microgravity Science Glovebox (MSG) Facility on the International Space Station (ISS). The SUBSA furnace was designed for growth of indium antimonide. It features a transparent section, which allows a side view of the melt, the solid-liquid (SL) interface and the growing crystal. In 2002, four Te- doped and three Zn-doped InSb crystals were grown in microgravity. Subsequently, the SUBSA furnace was used in several other materials science investigations, including growing the radiation detector materials InI and Cs2LiYCl6:Ce from the melt and vapor phase (2017 to 2019) and Brazing of Aluminum alloys in Space (BRAINS). A review of the SUBSA furnace features and parameters will be presented, including the design of the growth ampoules, charge preparation, and the procedures used to grow InSb (in 2002) and InI (in 2019).

A.G. Ostrogorsk↗
NASA NTRS2024

2023 Cleanroom Monitoring for OSIRIS-REx

OSIRIS-REx is an asteroid sample return mission that delivered asteroid regolith from Bennu to Earth on 9/24/2023 [1]. Cleanroom monitoring of OSIRIS-REx Curation facilities has been ongoing since 2021 when construction of the OSIRIS-REx lab at Johnson Space Center (JSC) was completed [2]. The monitoring continues inside of the OSIRIS-REx lab in Houston. Monitoring was also conducted on a temporary cleanroom constructed inside a hangar at the Utah Test and Training Range (UTTR) to initially receive the Sample Return Capsule (SRC) upon its landing there. The following reports on cleanroom monitoring that has taken place in the months leading up to as well as after OSIRIS-REx return. Monitoring techniques used include particle counts, deployment of Si wafer witness plates (Balazs, Inc.) and Al foil witness plates, gas sampling (Balazs, Inc.) and microbiological monitoring. We collected particle counts at both the lab at JSC as well as the temporary cleanroom at UTTR. Particle counts were taken monthly from six locations in the lab at JSC. Particle counts were taken from seven locations at UTTR in July, August, and September. The UTTR cleanroom particle counts were taken daily in the five days leading to OSIRIS-REx return as well as consistently the day of return (every 2 minutes and 15 seconds 7:21 am- 6:27 pm) from one location inside the cleanroom. The particle counts at UTTR consistently stayed well within the ranges of its required ISO 7 equivalent classification (352,000 maximum particles/ m3 ≥ 0.5 μm). Most analysis showed that the particle counts were far below ISO 7 requirements (highest measured count was 61,484 particles/ m3 ≥ 0.5 um). but the elevated instances correlated to exterior hangar doors being open. Particle counts were reduced when keeping exterior hangar doors closed. The particle counts at JSC have stayed consistently within their ISO 5 equivalent classification (3,520 maximum particles/ m3 ≥ 0.5 um). In most instances, the counts are much better except in one instance where the count measured 13,381 particles/ m3 ≥ 0.5 um. The high spike in particle counts in the JSC lab correlated with the air handlers being shut down temporarily the previous day. The particle counts taken in the same location quickly reduced and measured 0 when taken a month later with the air handlers on. We deployed 8-inch semiconductor polished Si wafer witness plates for 24-hour periods inside of the OSIRIS-REx Curation lab at JSC (in July, August, September, and November 2023) and the cleanroom at UTTR (July and September 2023) to test for possible organic and inorganic contaminants. We also deployed these wafers inside of the OSIRIS-REx Touch-and-Go sample Acquisition Mechanism (TAGSAM) glovebox (where Bennu sample processing occurs) and desiccator (Bennu sample storage) at JSC in August 2023. These samples were all sent to Balazs for analysis via Thermal Desorption Gas Chromatography Mass Spectroscopy (TD-GC-MS) to quantify organic compounds and vapor phase decomposition inductively coupled plasma mass spectrometry (VPD-ICP-MS) to quantify inorganic contaminants. We collected air samples using an adsorbent tube connected to a pump for six hours (100 mL/minute) inside of both the JSC lab and the UTTR cleanroom. These samples were taken at JSC in July, August, September, November, and December and at UTTR in July and September. Additionally, a sample was taken just outside of the TAGSAM glovebox airlock door in July. These samples were sent to Balazs for analysis of volatile organics in air. Overall, the OSIRIS-REx lab at JSC and cleanroom at UTTR yielded very low organic and inorganic contaminants (similar results to Genesis lab at JSC which is ISO 4 equivalent) except for boron, which is attributed to the borosilicate glass in the fan filter units. We collected monthly surface and air samples inside the JSC lab to monitor potential microbial contamination. We report the recovery rate for each sampling event, which is defined as the number of samples exhibiting bacterial or fungal growth divided by the total number of samples collected. Since the lab was commissioned in 2021 the median recovery rate is 29%. This recovery rate is consistent with other ISO 5 equivalent labs used to curate astromaterials collections. Increases in recovery rate correspond to construction and/or extra activity in the lab. However, increases in recovery rate do not reliably correlate to increases in particle counts, which highlights the need for a dedicated microbial monitoring program for biologically sensitive collections. We sampled the temporary clean room at UTTR in July, August, and September of 2023 to monitor potential microbial contamination. The recovery rate decreased from 80% in August to 29% in September. However, in all instances, the diversity of bacteria and fungi was higher in the UTTR cleanroom than in the JSC lab. We routinely collected more than twenty different organisms from the UTTR cleanroom. In the JSC lab the median diversity is 2 organisms. Based on these results we hypothesize that microbes from UTTR could be transported back to JSC with the Bennu samples. To mitigate this risk, in September of 2023, we implemented additional cleaning procedures in the JSC lab to reduce the bioburden on surfaces that could come into direct contact with hardware used to process Bennu samples. Since adopting these additional cleaning measures, the median recovery rate has decreased to 14%. We did not observe an increase in fungal or bacterial diversity in the lab in the October sampling. We will continue to monitor this trend closely for the next several months. Supported by NASA under Award NNH09ZDA007O and Contract NNM10AA11C.

Rachel Comstock Funk↗
NASA NTRSDate not supplied

Investigating Commercial Off-The-Shelf (COTS) Glovebox and Support Components Compared to Custom Curatorial Laboratories

There is a need envisioned to investigate the application of commercial off-the-shelf (COTS) systems as tools that could be used within commercial preliminary curation as the expected space economy is supported and begins to take flight. NASA is involved with supporting and developing the space economy [1] and therefore it’s feasible that at some point, a commercial space company would bring back materials and either store initially, or permanently, within COTS equipment as a stand-in for custom curation laboratories. While utilizing opportunities to explore this capability at NASA-Johnson Space Center (JSC) during the establishment of other laboratories [2] it was realized that cleanliness and/or other properties could be evaluated for these COTS systems during their installation in advanced research facilities that are not ISO-class rated clean rooms. Several aspects of a COTS-Curation system were explored including various gloves for curation manipulation within a negative pressure glovebox (Fig.1), Balazs organic and inorganic contaminant levels testing prior to glovebox ever being used, mode swapping comparison of recirculation vs. single pass, constant monitoring of oxygen (O2) and moisture (H2O) levels in various conditions, etc. To acquire inorganic and organic compound loads inside the glovebox, Balazs wafer testing and gas sampling were implemented. These are standardized analytical tests provided by Balazs™ NanoAnalysis, a division of Air Liquide USA. Deployment of 8-inch silicon wafer witness plates for 24-hours in an undisturbed environment capture the organic compound load and inorganic trace metal contents which can be obtained by Vapor Phase Decomposition Inductively Coupled Plasma Mass Spectrometry (VPD ICP-MS). Balazs gas sample analysis was also performed for better measurements of volatile organic compounds (VOC) in glovebox air analyzed by Thermal Desorption Gas Chromatography Mass Spectrometry (TD GC-MS). These analytical testings were carried out in a controlled ultra high pure (UHP) gaseous nitrogen (N2)-purged environment where oxygen and moisture contents were continuously monitored at certain temperature and pressure. The preliminary outcomes of these testings are promising. The COTS systems appear to maintain the steady-state controlled environment for days, if not weeks, with uninterrupted gaseous N2-supply which was operated from a standard medium pressure LN2 250L 230L dewar, exchanged as needed. The outgassing load can be maintained by selecting the glove materials that have the least outgassing and particle shedding performances. Further experiments will be considered to validate the preliminary findings. While this project is exploratory, it is not intended as an endorsement by NASA Curation for approved materials or usage for advanced curatorial activities. NASA does not endorse nor promote any one particular product or company. References: [1] McCubbin F. M. et al. (2019) Space Science Reviews 215:A48. [2] Lewis, E.K. et. al (2024) LPSC LV, Abstract #2457.

Curation↗
DOE OSTI2024

A Review of Modeling Approaches for Predicting Frost Growth and Defrosting on Tube-Fin Heat Exchangers: Preprint

Frost formation and growth on the evaporator surface is a common process that deteriorates the air-refrigerant heat transfer and restricts airflow. This degrades the performance of the vapor compression system by increasing temperature lift and air-side pressure drop. To accurately predict these effects during coil frosting, as well as the energy use and duration of the defrost process, there is a need to estimate the heat and mass transfer, momentum transport, and solid-liquid and liquid-vapor phase change. Therefore, in the past few decades, continuous effort has been made to model frosting and defrosting processes using approaches ranging from empirical correlations to computational fluid dynamic models. To provide a clearer overview for researchers, engineers, and manufacturers in this field, this paper provides a comprehensive literature review for frosting and defrosting models. The paper begins with theoretical background of frost formation and defrost processes, and then reviews the common modeling approaches in literature and their underlying assumptions when trying to account for various physical phenomenon. Based on the literature review, the most critical modeling effort for frost formation is the determination of frost densification rate and frost growth rate. Various methods to predict these two parameters are reviewed. Empirical correlations commonly used for frost density and thermal conductivity are presented and compared. For the defrost process, various multi-stage models have been proposed with different assumptions. Some assume the presence of air gap between the tube wall and the frost, while others consider the melted frost flow due to gravity. We also review physics-based and empirical approaches to integrate defrost models into heat pump models. We conclude by identifying research gaps and providing recommendations.

defrost↗
DOE OSTI2024

Development of a rate-based ENRTL-RK process model for a water-lean solvent

Advanced water-lean solvents (WLS) for post-combustion CO2 capture offer several advantages over the aqueous amine solvents . WLS have lower parasitic energy penalty, lower corrosion, lower temperature and high-pressure CO2 regeneration leading to lower cost of CO2 capture. RTI International, with funding from the US Department of Energy, has been developing its novel water-lean solvent, that has shown specific reboiler duty of 2.3 GJ/t-CO2 at the 60-kWe pilot testing unit (Tiller Plant, SINTEF, Norway) and 2.6 GJ/t-CO2 at the engineering scale testing system (12 MWe) at the Technology Centre Mongstad (TCM) in Norway. All heat duties, including the one from TCM testing, were consistent with Aspen Plus modeling of the specific configuration of each test plant. This work focuses on the development of a detailed process model using in-house laboratory measurements and process data at pilot scale. The eNTRL-RK model used in this work is based on an unsymmetric activity coefficient model with the reference states chosen to be pure liquids for solvents and ideal dilute solution at unit solute molality (resulting in activity coefficient of unity at infinite dilution) for electrolytes. It uses the Redlich-Kwong equation of state for vapor phase properties and Henry’s law for solubility of supercritical gases. The model was validated using process data from the pilot-scale campaign at the Tiller plant, and the engineering scale test campaign at TCM. Data on CO2 capture rate, absorber, and regenerator temperature profiles and specific reboiler duties from two different test campaigns at Tiller and TCM, were used to further refine and validate the model and the model compares favorably to experimental data. The validation results against TCM campaign will be presented in this work.

CO2 capture↗
NASA NTRS1971

Third-harmonic generation in phase-matched Rb vapor.

The generation of 0.3547-micron radiation was performed by tripling 1.064-micron radiation in a phase-matched mixture of rubidium vapor and xenon. A third-harmonic nonlinear susceptibility in Rb vapor is confirmed. It is about 100,000 times greater than that of He. This large susceptibility is due to the large oscillator strengths and resonant enhancements resulting from Rb transitions in the near infrared, visible, and UV.

Young, J. F.↗
DOE OSTI2025

Quantitative phase imaging around water vapor microbubbles under pulsed laser illumination

We measured water temperature around a self-oscillating water vapor-rich bubble using diffraction phase microscopy equipped with a pulsed laser. The water vapor-rich bubble, which causes a strong water flow around it, was generated by locally heating degassed water through the photothermal conversion properties of an FeSi2 thin film. The generation of the flow is related to the self-oscillation of the bubble at sub-MHz frequencies and the temperature distribution around it. Here, the refractive index of the surrounding water was measured using a pulsed laser with a 3.5-ns pulse duration, which guarantees a time resolution of less than 1/200 of the oscillation cycle of the bubble. The temperature distribution around the bubble was calculated from the measured refractive index.

Narihira, Kyoshiro [Kyoto University, Japan]↗