Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “small systems”

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 757 records · Page 42

Small Unmanned Aerial Systems (sUAS) on the NNSS White Paper

The Nevada National Security Site (NNSS) prides itself on being the premier outdoor, indoor, and underground national laboratory. It is the preferred location for experiments supporting the National Nuclear Security Administration’s nuclear weapons Stockpile Stewardship Programs, national defense programs, and national security research, development, and training programs, as well as vital programs of other federal agencies. Work at the NNSS supports the Stockpile Stewardship Program, Global and Homeland Security programs, and Environmental Management. The NNSS looks to incorporate safer work practices and continuous improvements. Unmanned Aerial Surveys (UAS) have already been implemented in areas off the NNSS for multiple uses. Using these best practices with systems catered to the NNSS would allow integration of new technology and would allow work at the NNSS to maintain the high level of quality already exhibited. The Management and Operating Contractor (M&O) has shown experience in multiple UAS platforms. Through the coordination and experience developed through these projects, the M&O can further improve the quality and cost effectiveness of services currently rendered and offer new services not currently available today. Several NNSS departments that could implement UAS technology are Emergency Response, Facility Management, Environmental Management, and Training. These departments would be able to improve their capabilities and expand personnel effectiveness with the inclusion of UASs and the information they provide.

61 RADIATION PROTECTION AND DOSIMETRY↗

Characteristics of refrigerant leaks from small HVAC&R systems

Reduced use of high global warming potential (GWP) hydrofluorocarbon (HFC) refrigerants is desired. However, many lower-GWP alternatives are flammable, some of higher flammability levels, or A3, and others of lower flammability (A2 or A2L).Safety standards for A2 and A3 flammable refrigerants, including the International Electrotechnical Commission (IEC) standard IEC 60335-2-40 calculate maximum flammable refrigerant charge limits using a fixed 4-minute leak time based on the time to leak 150 g of CO2 through a capillary tube.Actual refrigerant leak times depend on the equipment type, leak location, leak orifice diameter and equipment operation condition (on or off).Five systems were installed in test chambers with leak quantities and rates measured by tracking total system weight during the leak event. Among the major results were that almost all of the system charge was shown to escape the units, >80% within the first 10 minutes.

Patel, Viral↗

Experimentation of Synchronous and Variable Speed Small Scale Hydropower Systems

Hydropower is the one of the oldest renewable energy technologies and is wrongly thought of today as having little room to grow. The opportunity for new hydropower capacity is immense through both technology advancement and run-of-river new stream reach projects. Despite the age of hydropower, a divide in opinion is forming regarding how we should proceed with generating power from smaller undisturbed rivers and canals. Hydropower generation techniques have been primarily fixed speed since its inception in the late 19th century, but it seems as though variable speed generation could hold the key to more efficiently utilizing new stream reach resources. This research aims to provide a cost benefit analysis of fixed speed vs. variable speed hydropower generation topologies, and distinguish the performance advantages that variable speed generation could hold in other aspects of hydropower. Simulation results are validated with hardware.

13 HYDRO ENERGY↗

NASA Small Spacecraft and Distributed Systems Program - Recent and Upcoming Technology Demonstrations and Development Efforts

NASA’s Small Spacecraft & Distributed Systems (SSDS) program strengthens U.S. ability to conduct unique missions by rapidly developing and demonstrating capabilities for SmallSat exploration, science, and commercial space. In collaboration with NASA Centers, other government agencies, commercial industry, and academia, SSDS advances next generation SmallSat technologies like power, processing, propulsion, communications, autonomous navigation, architectures (swarms), and applications (AI/ML/Edge Computing)—to extend missions beyond LEO into cislunar and planetary space. Various investment mechanisms exist for SSDS to select and fund projects that will ultimately advance NASA’s Moon to Mars Architecture. Presented here are the latest achievements and findings from recently completed SSDS projects, along with updates from ongoing efforts and planned future work. Successful missions like Starling and CAPSTONE continue to demonstrate their capability after several years on-orbit. Advancements in next generation swarm configurations are being implemented by Starling for space traffic monitoring and management applications. Findings from recent SSDS flight projects are discussed: DiskSat, a unique SmallSat platform alternative to canisterized nanosatellites, launched December 2025 and is gathering data; the PTD series of missions concluded in December 2025. Current SSDS efforts are focused on addressing NASA Shortfalls relating to rendezvous and proximity operations, neuromorphic computing, and space situational awareness.

Roger C Hunter↗

Calculating potential energy curves with fixed-node diffusion Monte Carlo: CO and N 2

This study reports on the prospect for the routine use of Quantum Monte Carlo (QMC) for the electronic structure problem, applying fixed-node Diffusion Monte Carlo (DMC) to generate highly accurate Born-Oppenheimer potential energy curves (PECs) for small molecular systems. The singlet ground electronic states of CO and N 2 were used as test cases. The PECs obtained by DMC employing multiconfigurational trial wavefunctions were compared with those obtained by conventional high-accuracy electronic structure methods such as multireference configuration interaction and/or the best available empirical spectroscopic curves. The goal was to test whether a straightforward procedure using available QMC codes could be applied robustly and reliably. Results obtained with DMC codes were found to be in close agreement with the benchmark PECs, and the n 3 scaling with the number of electrons (compared with n 7 or worse for conventional high-accuracy quantum chemistry) could be advantageous depending on the system size. Due to a large pre-factor in the scaling, for the small systems tested here, it is currently still much more computationally intensive to compute PECs with QMC. Nevertheless, QMC algorithms are particularly well-suited to large-scale parallelization and are therefore likely to become more relevant for future massively parallel hardware architectures.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

Novel collective phenomena in high-energy proton–proton and proton–nucleus collisions

The observation of long-range rapidity correlations among particles in high-multiplicity p–p and p–Pb collisions created new opportunities for investigating novel high-density QCD phenomena in small colliding systems. We also review experimental results related to the study of collective phenomena in small systems at RHIC and the LHC along with the related developments in theory and phenomenology. Finally, perspectives on possible future directions for research are discussed with the aim of exploring emergent QCD phenomena.

74 ATOMIC AND MOLECULAR PHYSICS↗

Melting and freezing of a skyrmion lattice

We report comprehensive Monte–Carlo studies of the melting of skyrmion lattices (SkL) in systems of small, medium, and large sizes with the number of skyrmions ranging from 10 3 to over 10 5 . Large systems exhibit hysteresis similar to that observed in real experiments on the melting of SkLs. For sufficiently small systems which achieve thermal equilibrium, a fully reversible sharp solid–liquid transition on temperature with no intermediate hexatic phase is observed. A similar behavior is found on changing the magnetic field that provides the control of pressure in the SkL. Here, we find that on heating the melting transition occurs via a formation of grains with different orientations of hexagonal axes. On cooling, the fluctuating grains coalesce into larger clusters until a uniform orientation of hexagonal axes is slowly established. The observed scenario is caused by collective effects involving defects and is more complex than a simple picture of a transition driven by the unbinding and annihilation of dislocation and disclination pairs.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗

The Minitron system for growth of small plants under controlled environment conditions

The design and operation of a system is described in which small plants can be grown under controlled environment conditions. Important features of this 'Minitron' system include precise control of temperature and CO2 concentration in a flowing atmosphere. Plants can be grown either hydroponically or in solid root support medium. For either culture method, nutrient solution or water is added from an external reservoir, altering neither atmospheric composition nor temperature equilibrium within a closed Minitron chamber.

Akers, Carolyn P.↗

Mockup Small-Diameter Air Distribution System

This report investigates the feasibility of using a home-run manifold small-diameter duct system to provide space conditioning air to individual thermal zones in a low-load home. This compact layout allows duct systems to be brought easily within conditioned space via interior partition walls. Centrally locating the air hander unit in the house significantly reduces duct lengths. The plenum box is designed so that each connected duct receives an equal amount of airflow, regardless of the duct position on the box. Furthermore, within a reasonable set of length restrictions, each duct continues to receive similar airflow. The design method uses an additive approach to reach the total needed zonal airflow. Once the cubic feet per minute needed to satisfy the thermal load of a zone has been determined, the total number of duct runs to a zone can be calculated by dividing the required airflow by the standard airflow from each duct. The additive approach greatly simplifies the design effort and reduces the potential for duct design mistakes to be made. Measured results indicate that this plenum design can satisfy the heating load. However, the total airflow falls short of satisfying the cooling load in a hypothetical building. Static pressure inside the plenum box of 51.5 Pa limited the total airflow of the attached mini-split heat pump blower, thus limiting the total thermal capacity. Fan energy consumption is kept to 0.16 to 0.22 watt/CFM by using short duct runs and smooth duct material.

air distribution↗

Building America Case Study: Mockup Small-Diameter Air Distribution System

This report investigates the feasibility of using a home-run manifold small-diameter duct system to provide space conditioning air to individual thermal zones in a low-load home. This compact layout allows duct systems to be brought easily within conditioned space via interior partition walls. Centrally locating the air hander unit in the house significantly reduces duct lengths. The plenum box is designed so that each connected duct receives an equal amount of airflow, regardless of the duct position on the box. Furthermore, within a reasonable set of length restrictions, each duct continues to receive similar airflow. The design method uses an additive approach to reach the total needed zonal airflow. Once the cubic feet per minute needed to satisfy the thermal load of a zone has been determined, the total number of duct runs to a zone can be calculated by dividing the required airflow by the standard airflow from each duct. The additive approach greatly simplifies the design effort and reduces the potential for duct design mistakes to be made. Measured results indicate that this plenum design can satisfy the heating load. However, the total airflow falls short of satisfying the cooling load in a hypothetical building. Static pressure inside the plenum box of 51.5 Pa limited the total airflow of the attached mini-split heat pump blower, thus limiting the total thermal capacity. Fan energy consumption is kept to 0.16 to 0.22 watt/CFM by using short duct runs and smooth duct material.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗

Performance Analysis of a Modular Small-Diamter Air Distribution System

This report investigates the feasibility of using a home-run manifold small-diameter duct system to provide space conditioning air to individual thermal zones in a low-load home. This compact layout allows duct systems to be brought easily within conditioned space via interior partition walls. Centrally locating the air handler unit in the house significantly reduces duct lengths. The plenum box is designed so that each connected duct receives an equal amount of airflow, regardless of the duct position on the box. Furthermore, within a reasonable set of length restrictions, each duct continues to receive similar airflow. The design method uses an additive approach to reach the total needed zonal airflow. Once the cubic feet per minute needed to satisfy the thermal load of a zone has been determined, the total number of duct runs to a zone can be calculated by dividing the required airflow by the standard airflow from each duct. The additive approach greatly simplifies the design effort and reduces the potential for duct design mistakes to be made. Measured results indicate that this plenum design can satisfy the heating load. However, the total airflow falls short of satisfying the cooling load in a hypothetical building. Static pressure inside the plenum box of 51.5 Pa limited the total airflow of the attached mini-split heat pump blower, thus limiting the total thermal capacity. Fan energy consumption is kept to 0.16 to 0.22 watt/CFM by using short duct runs and smooth duct material.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗

Performance Analysis of a Modular Small-Diameter Air Distribution System

This report investigates the feasibility of using a home-run manifold small-diameter duct system to provide space-conditioning air to individual thermal zones in a low-load home. This compact layout allows duct systems to easily be brought within conditioned space via interior partition walls. Centrally locating the air handling unit in the house significantly reduces duct lengths. The plenum box is designed so that each connected duct receives a similar amount of airflow—regardless of its position on the box. Furthermore, within a reasonable set of length restrictions each duct continues to receive similar airflow.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗

Usability of Pre-Flight Planning Interfaces for Supplemental Data Service Provider Tools to Support Uncrewed Aircraft System Traffic Management

Small uncrewed aircraft systems (sUASs) operate in low-altitude, uncontrolled airspace – where support services for their operators (UASOs) are not currently provided. NASA’s System-Wide Safety (SWS) project is identifying the potential risks and hazards to sUAS operations to provide, inform, and improve the designs of In-time Aviation Safety Management Systems (IASMS). The IASMS will include a suite of data-driven tools that compile and analyze data collected from aviation systems and environmental sources to predict hazards, and provide information to allow operators to mitigate these risks (Young et al., 2020). These risk and hazard services can be run and displayed to operators on graphical user interfaces (GUIs), as they relate to a vehicle(s)’ route of flight. These interfaces offer both a means to present hazard service output and offer an opportunity to test user understanding of the information, user decision making, and the best ways to present such data to an operator. Based on these future technologies and intended missions, it is important to investigate interface requirements and evaluate how operators might use these tools. Presenting salient and meaningful risk assessment information to operators is necessary to increase situation awareness and ultimately safety. Building on previous research (Feldman et al., 2022), a usability study comparing two GUIs was conducted to explore how individuals interacted with different styles of information displays. A series of pre-flight hazard and risk-assessment tasks were developed to evaluate participant performance using the Supplemental Data Service Provider Consolidated Dashboard and the Human Automation Team Interface System interfaces. Participants were trained to use both GUIs and their performance was analysed across different scenarios involving multiple sUASs. Performance on simple tasks and the System Usability Scale scores were reported by Feldman et al., 2023. Additional analyses and evaluations on more complex tasks (e.g., risk assessment, prioritization), workload and response times are examined in this paper.

sUAV interfaces↗