Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “Caloric”

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 271 records · Page 15

Food Acceptability, Menu Fatigue, and Aversion on ISS Missions

The acceptability of the spaceflight food system has been linked to caloric intake and associated nutritional benefits. The diets of the United States Operating Segment crewmembers during a mission are restricted to 200 processed and prepackaged standard menu items supplemented with personal preference foods. ISS crew members have noted in debriefs that they would prefer more food variety for the length of the missions and they tire of certain foods over six months. It is possible that menu fatigue leads to decreases in acceptability and increased aversion to available foods, potentially contributing to the body mass loss often experienced by ISS crew. However, the impact of repeat food consumption on acceptability within the current spaceflight food system has not yet been systematically investigated. Limited variety and crew preferences within food categories may have more severe physical and behavioral health and performance consequences as mission duration increases. Characterizing the relationship between food acceptability and mission duration will contribute to defining requirements for an acceptable food system that will support crew health and performance on long duration missions.

Douglas, Grace L.↗

A Regional Nuclear Conflict Would Compromise Global Food Security

A limited nuclear war between India and Pakistan could ignite fires large enough to emit more than 5 Tg of soot into the stratosphere. Climate model simulations have shown severe resulting climate perturbations with declines in global mean temperature by 1.8 ◦C and precipitation by 8%, for at least 5 y. Here we evaluate impacts for the global food system. Six harmonized state-of-the-art crop models show that global caloric production from maize, wheat, rice, and soybean falls by 13 (±1)%, 11 (±8)%, 3 (±5)%, and 17 (±2)% over 5 y. Total single-year losses of 12 (±4)% quadruple the largest observed historical anomaly and exceed impacts caused by historic droughts and volcanic eruptions. Colder temperatures drive losses more than changes in precipitation and solar radiation, leading to strongest impacts in temperate regions poleward of 30◦N, including the United States, Europe, and China for 10 to 15 y. Integrated food trade network analyses show that domestic reserves and global trade can largely buffer the production anomaly in the first year. Persistent multiyear losses, however, would constrain domestic food availability and propagate to the Global South, especially to food-insecure countries. By year 5, maize and wheat availability would decrease by 13% globally and by more than 20% in 71 countries with a cumulative population of 1.3 billion people. In view of increasing instability in South Asia, this study shows that a regional conflict using <1% of the worldwide nuclear arsenal could have adverse consequences for global food security unmatched in modern history.

Jaegermeyr, Jonas↗

Exploring uncertainties in global crop yield projections in a large ensemble of crop models and CMIP5 and CMIP6 climate scenarios

Concerns over climate change are motivated in large part because of their impact on human society. Assessing the effect of that uncertainty on specific potential impacts is demanding, since it requires a systematic survey over both climate and impacts models. We provide a comprehensive evaluation of uncertainty in projected crop yields for maize, spring and winter wheat, rice, and soybean, using a suite of nine crop models and up to 45 CMIP5 and 34 CMIP6 climate projections for three different forcing scenarios. To make this task computationally tractable, we use a new set of statistical crop model emulators. We find that climate and crop models contribute about equally to overall uncertainty. While the ranges of yield uncertainties under CMIP5 and CMIP6 projections are similar, median impact in aggregate total caloric production is typically more negative for the CMIP6 projections (+1% to −19%) than for CMIP5 (+5% to −13%). In the first half of the 21st century and for individual crops is the spread across crop models typically wider than that across climate models, but we find distinct differences between crops: globally, wheat and maize uncertainties are dominated by the crop models, but soybean and rice are more sensitive to the climate projections. Climate models with very similar global mean warming can lead to very different aggregate impacts so that climate model uncertainties remain a significant contributor to agricultural impacts uncertainty. These results show the utility of large-ensemble methods that allow comprehensively evaluating factors affecting crop yields or other impacts under climate change. The crop model ensemble used here is unbalanced and pulls the assumption that all projections are equally plausible into question. Better methods for consistent model testing, also at the level of individual processes, will have to be developed and applied by the crop modeling community.

crop yield projections↗

Selection Factors for Space Crops

NASA is actively researching space crop production to determine its potential to contribute to food system security on long duration missions beyond Low Earth Orbit. Our near-term focus is on nutrient and variety supplementation of prepackaged food with fresh produce that requires little or no processing. The longer-term goal is caloric replacement to become less dependent on Earth, and this will require cultivation of staple crops, processing and cooking equipment, integration with spacecraft air, water, and power systems, and automation. There are numerous technology and knowledge gaps remaining for sustainable space crop production systems, but one high-impact area is in the development of crops specifically customized to meet the needs of controlled environment crop production, astronaut health and well-being, and space-unique environments. Modern crop breeding and genome engineering tools are allowing for rapid development of new genotypes with incredible specificity. Targeted aspects to optimize crops for space have been identified and characterized into five categories: plant growth and development, plant physiology, produce nutrition, produce organoleptic acceptability, and postharvest characteristics. Within each category there are several targets that further the development of crop production systems for spaceflight, such as crop size and harvest index, tolerance to specific environmental stresses, optimizing target nutrients that are low or degrade in the packaged diet, maintenance time requirements, and less indigestible structural material. NASA-funded PIs are already beginning to develop candidate crops, and spaceflight testing and validation of novel space crops is on the horizon. Crops developed for space also have the potential to benefit terrestrial controlled environment agriculture crop production systems. This research was supported by NASA’s Space Biology and Human Research Programs.

Space Crop Production↗

Gaps List KSC Space Crop Production Project Scientist: Interview Evaluation

The Space Crop Production (SCP) at the NASA Kennedy Space Center (KSC) is aimed at achieving nutrient supplementation and moving towards caloric independence from Earth by growing crops for astronauts. However, growing crops outside of Earth’s orbit creates many new challenges. The KCS SCP Project Scientists have developed a method of organizing these challenges, called the Gaps List. This Gaps List is a dynamic, taxonomically arranged list of missing knowledge and technologies needed to reach production goals. The purpose of this evaluation was to assess the effectiveness and current research coverage of the Gaps List by using it to document the KSC SCP Program research. In evaluating the research, it was determined that several needs within the SCP Program that are not being met, and many deficiencies within the Gaps List were encountered. Gaps involving hardware were largely unrecognized by the KSC researchers and the funding sources that would typically support them. The KSC SCP Project will require more engineering and physical sciences support to close those gaps. The Gaps List was found to be out of date and in need of rearrangement. A recommendation from this review was that the Gaps List be reassessed at regular intervals to ensure all gaps and relevant research topics are included. In order to better understand the gaps within the list, any assessment needs to include a measure of priority, dependency and breadth. These measures may be included within or along side the current taxonomical arrangement of the Gaps List.

Space Crop Production↗

Gaps List KSC Space Crop Production Project Scientist: Interview Evaluation

The Space Crop Production (SCP) Program at the NASA Kennedy Space Center (KSC) is aimed at achieving nutrient supplementation and moving towards caloric independence from Earth by growing crops for astronauts. However, growing crops outside of Earth’s orbit creates many new challenges. The KCS SCP Project Scientists have developed a method of organizing these challenges, called the Gaps List. This Gaps List is a dynamic, taxonomically arranged list of missing knowledge and technologies needed to reach production goals. The purpose of this evaluation was to assess the effectiveness and current research coverage of the Gaps List by using it to document KSC SCP Program research. It was determined that there are several needs within the SCP Program that are not being met, as well as, many deficiencies within the Gaps List. Gaps involving hardware were largely unrecognized by both the KSC researchers and the funding sources that would typically support them. The KSC SCP Project will require more engineering and physical sciences support to fill those gaps. The Gaps List was found to be out of date and in need of rearrangement. A recommendation from this review was that the Gaps List be reassessed at regular intervals to ensure all gaps, and relevant research topics are included. To better understand the gaps within the list, any assessment needs to include a measure of priority, dependency, and breadth. These measures may be included within or alongside the current taxonomical arrangement of the Gaps List.

Chloe Sophia Alexander↗

Gaps List KSC Space Crop Production Project Scientist: Interview Evaluation

The Space Crop Production (SCP) Program at the NASA Kennedy Space Center (KSC) is aimed at achieving nutrient supplementation and moving towards caloric independence from Earth by growing crops for astronauts. However, growing crops outside of Earth’s orbit creates many new challenges. The KCS SCP Project Scientists have developed a method of organizing these challenges, called the Gaps List. This Gaps List is a dynamic, taxonomically arranged list of missing knowledge and technologies needed to reach production goals. The purpose of this evaluation was to assess the effectiveness and current research coverage of the Gaps List by using it to document KSC SCP Program research. It was determined that there are several needs within the SCP Program that are not being met, as well as, many deficiencies within the Gaps List. Gaps involving hardware were largely unrecognized by both the KSC researchers and the funding sources that would typically support them. The KSC SCP Project will require more engineering and physical sciences support to fill those gaps. The Gaps List was found to be out of date and in need of rearrangement. A recommendation from this review was that the Gaps List be reassessed at regular intervals to ensure all gaps, and relevant research topics are included. To better understand the gaps within the list, any assessment needs to include a measure of priority, dependency, and breadth. These measures may be included within or alongside the current taxonomical arrangement of the Gaps List.

Chloe S. Alexander↗

Selection Factors for Space Crops

NASA is actively researching space crop production to determine its potential to contribute to food system security on long duration missions beyond Low Earth Orbit. Our near-term focus is on nutrient and variety supplementation of prepackaged food with fresh produce that requires little or no processing. The longer-term goal is caloric replacement to become less dependent on Earth, and this will require cultivation of staple crops, processing and cooking equipment, integration with spacecraft air, water, and power systems, and automation. There are numerous technology and knowledge gaps remaining for sustainable space crop production systems, but one high-impact area is in the development of crops specifically customized to meet the needs of controlled environment crop production, astronaut health and well-being, and space-unique environments. Modern crop breeding and genome engineering tools are allowing for rapid development of new genotypes with incredible specificity. Targeted aspects to optimize crops for space have been identified and characterized into five categories: plant growth and development, plant physiology, produce nutrition, produce organoleptic acceptability, and postharvest characteristics. Within each category there are several targets that further the development of crop production systems for spaceflight, such as crop size and harvest index, tolerance to specific environmental stresses, optimizing target nutrients that are low or degrade in the packaged diet, maintenance time requirements, and less indigestible structural material. NASA-funded PIs are already beginning to develop candidate crops, and spaceflight testing and validation of novel space crops is on the horizon. Crops developed for space also have the potential to benefit terrestrial controlled environment agriculture crop production systems. This research was supported by NASA’s Space Biology and Human Research Programs.

Space Crop Production↗

Food Acceptability, Menu Fatigue, and Aversion During the Sirius-21 Analog Mission

Spaceflight food systems are closed systems, meaning they are restricted to the variety and quantity of food launched within resource limitations of the mission. The acceptability of the food system has been linked to caloric intake and associated nutritional benefits. ISS crew members receive substantial personal food preferences (around 25% of their total intake) but have noted in debriefs that they would prefer more food variety and preference for the length of the missions and they tire of certain foods over six months. Limits on variety and personal preference are expected to increase as missions become further from Earth. It is possible that menu fatigue leads to decreases in acceptability and increased aversion to available foods that may contribute to the body mass loss often experienced by spaceflight crews. However, the impact of repeat food consumption on acceptability has not yet been systematically investigated across potential spaceflight food systems. Limited variety and crew preferences within food categories may have more severe physical and behavioral health and performance consequences as mission duration increases. Characterizing the relationship between food acceptability and mission duration will contribute to defining requirements for an acceptable food system that will support crew health and performance on long duration missions. This study evaluated acceptability of the food system used in the SIRIUS-21 8-month mission in Moscow, Russia. To capture in situ scoring of repeat consumption experiences, we administered a weekly food acceptability questionnaire to all 5 crewmembers throughout the mission. Crewmembers scored foods they consumed at 3 meals every 6 days on a 9-point hedonic scale and provided open-ended feedback regarding food context, attributes, and the meal. The sequence was intended to capture all days in the 7-day menu cycle. The repetition was intended to target repeat food ratings that may provide insight into onset of menu fatigue where they might stop eating some foods or limit their choices to their favorites. Every 30 days crewmembers completed two additional surveys to characterize the food system, any changes to the food system, and their experience with the food system. Data collection is complete. Data are currently being assessed by descriptive statistics and visualizations of the ratings over time. The primary goal is to look for trends in the trajectories of ratings of the food items over time – both within and between individuals – to determine if there are substantial decreases in acceptability across all foods, or within specific food categories (e.g., vegetables). The number of times a particular item is scored provides some information on the frequency of consumption (preference), and the overall number of unique items can give a measure of overall variety. We will assess whether individuals were more likely to have more observations on food items that are rated higher, and whether those who rated foods higher had more or less overall variety. Since the data are composed of longitudinal subjective ratings, repeated measures techniques will be used to quantify trends over time and how these may relate to preference and variety. We will assess how these trends relate to their characterization of and experience with the SIRIUS-21 food system. We will also provide content analysis of any additional feedback collected on the open-ended questions and debrief interviews.

Grace L. Douglas↗

A Computational Study of Plume Modeling for Space Launch System Abort Scenarios

A series of viscous CFD simulations depicting Space Launch System (SLS) post Mode-1abort scenarios are conducted and analyzed. The primary purpose of these simulations is to study the effect of launch abort vehicle attitude control motor (ACM) and abort motor(AM) plume modeling fidelity on the drag of the aborted core stage. The simulations are first conducted with a fully-coupled, multi-species and chemically reacting model for the freestream gases and the solid rocket abort motor combustion products. Following this, equivalent species are created for the ACM and AM exhaust gases. These equivalent species aim to provide near the same results for core stage drag as the chemically reacting model at a significantly lower computational cost. Finally, the exhaust gases are modeled as calorically perfect air. It was concluded that under most scenarios, both the equivalent species and the perfect air models predict the drag of the aborted core stage sufficiently close to that predicted by the chemically reacting simulations. In these cases, the flow and geometry conditions did not induce significant changes in the composition of the ‘true’ exhaust gas via afterburning of the combustion products. For cases where this was not the case, the properties of the essentially frozen equivalent species and perfect air models deviated from the true mixture, yielding unsatisfactory results. Finally, the accuracy improvements by using the chemically reacting model are weighed against the significant increase in associated computational costs. It was found that the simplified exhaust gas models are at least 4 times less expensive than the chemically reacting model. This may justify the judicious use of these simple models in future work.

CFD↗

A Computational Study of Plume Modeling for Space Launch System Abort Scenarios

A series of viscous CFD simulations depicting Space Launch System (SLS) post Mode-1abort scenarios are conducted and analyzed. The primary purpose of these simulations is to study the effect of launch abort vehicle attitude control motor (ACM) and abort motor(AM) plume modeling fidelity on the drag of the aborted core stage. The simulations are first conducted with a fully-coupled, multi-species and chemically reacting model for the freestream gases and the solid rocket abort motor combustion products. Following this, equivalent species are created for the ACM and AM exhaust gases. These equivalent species aim to provide near the same results for core stage drag as the chemically reacting model at a significantly lower computational cost. Finally, the exhaust gases are modeled as calorically perfect air. It was concluded that under most scenarios, both the equivalent species and the perfect air models predict the drag of the aborted core stage sufficiently close to that predicted by the chemically reacting simulations. In these cases, the flow and geometry conditions did not induce significant changes in the composition of the ‘true’ exhaust gas via afterburning of the combustion products. For cases where this was not the case, the properties of the essentially frozen equivalent species and perfect air models deviated from the true mixture, yielding unsatisfactory results. Finally, the accuracy improvements by using the chemically reacting model are weighed against the significant increase in associated computational costs. It was found that the simplified exhaust gas models are at least 4 times less expensive than the chemically reacting model. This may justify the judicious use of these simple models in future work.

CFD↗

Turbulence Model Validation through Joint Experimental / Computational Studies of Separated Flow Over a Three-Dimensional Tapered Bump: Part II - Computational Investigation

This report serves as documentation of activities related to Computational Fluid Dynamics (CFD) analysis applied to the Smooth Body Separation Experiment designed to produce validation-quality experimental data from wind-tunnel tests performed at the University of Notre Dame. All CFD analysis utilized the Boeing CFD (BCFD) flow solver. BCFD was used to analyze flow over the Boeing Speed Bump with second-order accuracy in space and time. Inviscid fluxes were computed using the HLLE scheme for steady-state simulations, and the Low-Dissipation Roe scheme for time-accurate simulations. The working fluid was modeled as calorically perfect air using Sutherland's law for viscosity. Thermal diffusivity was determined by assuming a constant molecular Prandtl number of 0.72, and a turbulent Prandtl number of 0.9. Reynolds Averaged Navier-Stokes (RANS) simulations were conducted using the one-equation Spalart-Allmaras turbulence model with rotation correction3 and the quadratic constitutive relation (SA-RC-QCR), as well as Menter's two-equation, Shear-Stress Transport (SST) model. Time-accurate computations were conducted using Delayed Detached eddy Simulation (DDES) with the one-equation RANS model, and Large Eddy Stress balance (LESb) with the two-equation RANS model. Implicit dual-time stepping was used to achieve second-order temporal accuracy. The experimental investigation conducted during the course of this study is described in detail in an accompanying report.

Flow separation↗

CALOR2012 XVth International Conference on Calorimetry in High Energy Physics

The International Conferences on Calorimetry in High Energy Physics, or the CALOR series, have always been where the calorimeter experts come together to review the state of calorimetry and bring forth new ideas every two years. The fteenth conference, CALOR2012, in Santa Fe was no exception. Although they were built roughly a decade ago, we are now witnessing the exceptional power of the LHC calorimeters and the crucial role they have been playing in the discovery of the 125 GeV Higgs-like boson. As we ruminate on the coming generation of experiments at the next (linear) collider and on the upgrades at the LHC, we are heartened by the substantial advances we made in calorimetry in the last decade. These advances will certainly help uncover new physics in the years to come, not only at colliders but also in astroparticle experiments that take advantage of natural elements such as air, water, and ice. The proceedings were published by the IOP in Journal of Physics, Vol 404 2011. The conference web site is calor2012.ttu.edu.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

R 5 T 4 compounds - unique multifunctional intermetallics for basic research and applications

The unique properties of the rare-earth elements and their alloys have brought them from relative obscurity to high profile use in common high-tech applications. The broad technological impact of these remarkable materials may have never been known by the general public if not for the supply concerns that placed the rare-earth materials on the front page of newspapers and magazines. Neodymium and dysprosium, two essential components of Nd 2 Fe 14 B-based high-performance permanent magnets, have drawn much attention and have been deemed critical materials for many energy-related applications. Ironically, the notoriety of rare-earth elements and their alloys is the result of a global movement to reduce their use in industrial applications and, thus, ease concerns about their supply and ultimately to reduce their position in high-tech supply chains. Research into the applications of lanthanide alloys has been de-emphasized recently due to the perception that industry is moving away from the use of rare-earth elements in new products. While lanthanide supply challenges justify efforts to diversify the supply chain, a strategy to completely replace the materials overlooks the reasons rare earths became important in the first place -- their unique properties are too beneficial to ignore. Rare-earth alloys and compounds possess truly exciting potential for basic science exploration and application development such as solid-state caloric cooling. In this brief review, we touch upon several promising systems containing lanthanide elements that show important and interesting magnetism-related phenomena.

36 MATERIALS SCIENCE↗

Estrategias de agua caliente para edificios comerciales: Una guia breve

Las calderas comerciales utilizan gas combustible o petroleo, y a veces electricidad, para producir agua caliente o vapor que se distribuye en un edificio para calefaccion de espacios y/o agua caliente sanitaria. Las calderas se encuentran en edificios de todos los tamanos, desde viviendas residenciales hasta grandes complejos comerciales y, en general, las calderas se vuelven menos eficientes y confiables con el tiempo. La vida util media de una caldera de gas es de 24 a 35 anos1 y, aunque la caldera continue funcionando, se debe planificar su reemplazo alrededor de los 15 a 20 anos de antiguedad o cuando aumentan las necesidades de mantenimiento. La lista de opciones de equipo para reemplazar calderas a gas esta creciendo, especialmente en lo que respecta a bombas de calor. Es fundamental evaluar las opciones para identificar la mejor solucion antes de su instalacion, antes de que sea necesario un reemplazo urgente. En muchos edificios existentes, el equipo se reemplaza con poca planificacion, lo que puede resultar en una operacion ineficiente, mayores costos y mantener al edificio en un ciclo de 25 anos de alto consumo energetico y emisiones. Al planificar un nuevo sistema de agua caliente, se deben considerar las emisiones de carbono, el consumo de energia, los costos y los cambios en las demandas del edificio para lograr un sistema optimo. Un enfoque colaborativo, integral e innovador puede resultar en un sistema mas limpio, energeticamente eficiente y rentable que cumpla con las necesidades de su instalacion y favorezca la disminucion de emisiones en el lugar. Este documento informativo asiste a propietarios y administradores de edificios en la planificacion del reemplazo de calderas, comprendiendo las opciones y encontrando las soluciones mas adecuadas para su situacion.

caldera↗

Background model systematics for the Fermi GeV excess

The possible gamma-ray excess in the inner Galaxy and the Galactic center (GC) suggested by Fermi-LAT observations has triggered a large number of studies. It has been interpreted as a variety of different phenomena such as a signal from WIMP dark matter annihilation, gamma-ray emission from a population of millisecond pulsars, or emission from cosmic rays injected in a sequence of burst-like events or continuously at the GC. We present the first comprehensive study of model systematics coming from the Galactic diffuse emission in the inner part of our Galaxy and their impact on the inferred properties of the excess emission at Galactic latitudes 2° < |b| < 20° and 300 MeV to 500 GeV. We study both theoretical and empirical model systematics, which we deduce from a large range of Galactic diffuse emission models and a principal component analysis of residuals in numerous test regions along the Galactic plane. We show that the hypothesis of an extended spherical excess emission with a uniform energy spectrum is compatible with the Fermi-LAT data in our region of interest at 95% CL. Assuming that this excess is the extended counterpart of the one seen in the inner few degrees of the Galaxy, we derive a lower limit of 10.0° (95% CL) on its extension away from the GC. We show that, in light of the large correlated uncertainties that affect the subtraction of the Galactic diffuse emission in the relevant regions, the energy spectrum of the excess is equally compatible with both a simple broken power-law of break energy E{sub break} = 2.1 ± 0.2 GeV, and with spectra predicted by the self-annihilation of dark matter, implying in the case of b-bar b final states a dark matter mass of m{sub χ}=49{sup +6.4}{sub −5.4} GeV.

79 ASTRONOMY AND ASTROPHYSICS↗

The Galactic Center GeV excess from a series of leptonic cosmic-ray outbursts

It has been proposed that a recent outburst of cosmic-ray electrons could account for the excess of GeV-scale gamma rays observed from the region surrounding the Galactic Center. After studying this possibility in some detail, we identify scenarios in which a series of leptonic cosmic-ray outbursts could plausibly generate the observed excess. The morphology of the emission observed outside of ∼1{sup o}−2{sup o} from the Galactic Center can be accommodated with two outbursts, one which took place approximately ∼10{sup 6} years ago, and another (injecting only about 10% as much energy as the first) about ∼10{sup 5} years ago. The emission observed from the innermost ∼1{sup o}−2{sup o} requires one or more additional recent outbursts and/or a contribution from a centrally concentrated population of unresolved millisecond pulsars. In order to produce a spectrum that is compatible with the measured excess (whose shape is approximately uniform over the region of the excess), the electrons from the older outburst must be injected with significantly greater average energy than those injected more recently, enabling their spectra to be similar after ∼10{sup 6} years of energy losses.

79 ASTRONOMY AND ASTROPHYSICS↗

Unlocking large compressive strains in thin active elastocaloric layers

Elastocaloric cooling attracts broad interest and rapidly growing attention due to its potential for high efficiency and low environmental impact. While it is common knowledge that triggering reversible entropy and temperature changes with stress applied in compression prevents rapid failures of materials, realizing this regime in elastocaloric systems is highly challenging because nearly all geometries suited for efficient heat transfer are prone to buckling even under modest loads. This work describes a concept of a novel composite, where an active NiTi layer is embedded into a polymer support structure such that the elastocaloric material is entirely in compression when the assembly is subjected to bending. The active layer achieves 8.1 K temperature change at 2.5% compressive strain without buckling. After 10,000 cycles at 2% compressive strain, the composite maintains mechanical integrity without degradation of the elastocaloric effect. The results demonstrate that NiTi and, potentially, other elastocalorically active materials in geometries previously thought impossible can be successfully implemented in regenerative cooling systems operating in compression.

42 ENGINEERING↗