SEARCH · Search NASA

Results for “flat sheet”

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.

SourceResearch connectionFrom yearThrough year

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 55 records · Page 3

All sources NASA NTRS DOE OSTI

DOE OSTI2022

Kinetic Model for Moisture-Controlled CO 2 Sorption

The understanding of the sorption/desorption kinetics is essential for practical applications of moisture-controlled CO 2 sorption. We introduce an analytic model of the kinetics of moisture-controlled CO 2 sorption and its interpretation in two limiting cases. In one case, chemical reaction kinetics on pore surfaces dominates, in the other case, diffusive transport through the sorbent defines the kinetics. Here, we show that reaction kinetics, which is dominant in the first case, can be expressed as a linear combination of 1st and 2nd order kinetics in agreement with the static isotherm equation derived and validated in a previous paper. The interior transport kinetics can be described by non-linear diffusion equations. By combining all carbon species into a single equation, we can eliminate — in certain limits — the source terms associated with chemical reactions. In this case, the governing equation is ∂θ/∂t = –∇ · (–D eff ∇ θ ). For a sorbent in a form of a flat sheet or a membrane, one can maintain the same functional form of a diffusion equation by introducing a generalized effective diffusivity D M that combines contributions from both surface chemical reaction kinetics and interior diffusive transport kinetics. Experimental data of transient CO 2 flux in a preconditioned commercial anion exchange membrane fit well to the 1st order model as long as very dry states are avoided, validating the theory. The observed DM for a preconditioned commercial anion exchange membrane ranges from 6.6× 10 -14 to 7.1× 10 -14 m 2 s -1 at 35°C. These small values compared to typical ionic diffusivities imply a very slow kinetics, which will be the largest issue that needs to be addressed for practical application. The collected transient CO 2 flux data are used to predict the magnitude of a continuous CO 2 pumping flux in an active membrane that transports CO 2 against a CO 2 concentration gradient. The pumped CO 2 flux is supported by water flux due to a water concentration gradient.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

DOE OSTI2011

Improved Scanning Geometry to Collect 3D-Geometry Data in Flat Samples

3D integration through silicon technology of integrated circuits challenges non-destructive testing methods. 3D x-ray methods are the techniques of choice to localize defects in interconnects. The development of high-power x-ray sources enabled the use of x-ray microscopy in laboratory tools. Those devices are able to resolve features down to 40 nm in an acceptable measurement time. However, the field of view is very limited to 16 {mu}m in high-resolution mode and to 65 {mu}m in large-field-of-view mode. To record tomography data, the size of the samples must not exceed the field of view to circumvent specific artifacts. Semiconductor samples usually do not fulfill the condition mentioned above since they have the shape of flat sheets. Therefore limited-angle tomography is typically used. The missing angles cause typical capping artifacts and poor signal-to-noise ratio. We present a modified scanning geometry that overcomes some of the artifacts and yields a better image quality. The geometry and potential applications are presented in comparison to the traditional limited-angle tomography.

07 ISOTOPE AND RADIATION SOURCES↗

DOE OSTI2019

Inter-digital capacitive sensor for evaluating cable jacket and insulation aging

An inter-digital capacitive (TDC) sensor has previously been used to measure dielectric properties of cable insulation polymer material when placed in direct contact with the insulation. Often cable insulation is covered by a polymer jacket. The dielectric properties of many cable jacket and insulation polymers are known to change due to thermal and radiation exposure-related damage. These dielectric properties frequently track with other measures of cable aging, such as tensile elongation-at-break and indenter modulus that have been broadly established as cable insulation polymer assessment methods. The external jacket of a cable is likely to have a different permittivity from the underlying insulation, and frequently the jacket material exhibits more severe damage than the insulation material due to environmental exposure. Because the jacket serves primarily to guard the cable during installation, as long as the underlying insulation condition is acceptable, the jacket condition is relatively unimportant in service. As part of a continuing program to develop and evaluate nondestructive examination methods that may be applied to cable condition assessment, a set of tools has been developed including (1) a parallel-plate sensor to directly measure the permittivity spectrum of flat sheet material and (2) an TDC and fixture to measure the effect of cable polymer dielectric property change on the sensor response. The TDC consists of two fork-like electrodes facing each other with the fork tines interspersed and separated by a small gap. The electrodes are printed on one side of a flexible substrate that can be conformed to the surface of a cylindrical cable, with tines parallel to the cable axis. The electrodes are connected to a broad-frequency-spectral impedance meter that senses the capacitance between the narrowly gapped electrode tines. This capacitance is known to vary as a function of the permittivity of any material in close proximity to the electrodes. By finite element modeling (FEM) and experimentation, this study investigates the effect of tine spacing and other design parameters associated with the TDC on the voltage (potential) distribution and electric field depth of penetration. The TDC measurement of an unshielded ethylene-propylene rubber (EPR)-insulated cable is shown to track with the degree of aging and quantities obtained by established methods. For jacketed cable systems, the TDC response is dominated by the jacket but, by analyzing measurements from TDC sensors with different depths-of-field penetration into the cable under test, the influence of the chlorinated polyethylene (CPE) cable jacket material degradation can be separated from an assessment of the cable insulation thereby enabling assessment of the insulation beneath/through the jacket.

Cable NDE, Interdigital Capacitance, Cable test↗

DOE OSTI2025

Self-assembly of wood-based shape memory composites triggered by solar-thermal energy

Transporting and assembling large, complex structures poses significant challenges due to their size, geometry, and cost. Additionally, the installation sites are often inaccessible or hazardous for humans, necessitating self-assembling capabilities in these structures. To mitigate these challenges, we propose using 3D printing materials with shape memory effect (SME) for both transport and construction. This approach involves developing 3D modular components into flat sheets for easier transportation, and then self-assembling into 3D structures on-site using solar energy. To gain a deeper understanding of the factors influencing material memory performance, we have chosen a composite PLA/WF, which is polylactic acid (PLA) with 20 wt% wood flour (WF) for this purpose, leveraging its high tensile modulus at 0.966 GPa, low cost, and sustainability. Printed shapes with this material can maintain a recovery ratio over 90% after 3 cycles. While traditional composites fillers (e.g. glass or carbon fiber) are added to enhance mechanical and thermal properties, the addition of bio-based fillers like WF accomplish similar goals without compromising sustainability. We conducted multiple experiments to demonstrate how environmental conditions (i.e. temperature) maximize the material’s SME. Although still at an early stage, this study provides initial insights into bridging the gap between the small-scale nature of shape memory polymers (SMPs) and their potential for large-scale additive manufacturing, addressing a critical need for efficient and sustainable construction. In the long term, we hope our study contributes to the design vision of utilizing SMPs for transportation, assembly, and deployment of complex structures, providing a new pathway for sustainable construction and transportation of large-scale structures to hard-to-access locations such as disaster-affected areas and remote deserts, etc.

4D printing↗

DOE OSTI2021

Helical magnetic order and Fermi surface nesting in noncentrosymmetric ScFeGe

Here, an investigation of the structural, magnetic, thermodynamic, and charge transport properties of noncentrosymmetric hexagonal ScFeGe reveals it to be an anisotropic metal with a transition to a weak itinerant incommensurate helimagnetic state below T N =36 K. Neutron diffraction measurements discovered a temperature and field independent helical wave vector k = (0 0 0.193) with magnetic moments of 0.53 μ B per Fe confined to the ab-plane. Density functional theory calculations are consistent with these measurements and find several bands that cross the Fermi level along the c-axis with a nearly degenerate set of flat bands just above the Fermi energy. The anisotropy found in the electrical transport is reflected in the calculated Fermi surface, which consists of several warped flat sheets along the c-axis with two regions of significant nesting, one of which has a wave vector that closely matches that found in the neutron diffraction. The electronic structure calculations, along with a strong anomaly in the c-axis conductivity at TN, signal a Fermi surface driven magnetic transition, similar to that found in spin density wave materials. Magnetic fields applied in the ab-plane result in a metamagnetic transition with a threshold field of ≈ 6.7 T along with a sharp, strongly temperature dependent discontinuity and a change in sign of the magnetoresistance for in-plane currents. Thus, ScFeGe is an ideal system to investigate the effect of in-plane magnetic fields on a helimagnet with a c-axis propagation vector, where the relative strength of the magnetic interactions and anisotropies determine the topology and magnetic structure.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗

DOE OSTI2015

Protection of extreme ultraviolet lithography masks. II. Showerhead flow mitigation of nanoscale particulate contamination [Protection of EUV lithography masks II: Showerhead flow mitigation of nanoscale particulate contamination]

An analysis is presented of a method to protect the reticle (mask) in an extreme ultraviolet (EUV) mask inspection tool using a showerhead plenum to provide a continuous flow of clean gas over the surface of a reticle. The reticle is suspended in an inverted fashion (face down) within a stage/holder that moves back and forth over the showerhead plenum as the reticle is inspected. It is essential that no particles of 10-nm diameter or larger be deposited on the reticle during inspection. Particles can originate from multiple sources in the system, and mask protection from each source is explicitly analyzed. The showerhead plate has an internal plenum with a solid conical wall isolating the aperture. The upper and lower surfaces of the plate are thin flat sheets of porous-metal material. These porous sheets form the top and bottom showerheads that supply the region between the showerhead plate and the reticle and the region between the conical aperture and the Optics Zone box with continuous flows of clean gas. The model studies show that the top showerhead provides robust reticle protection from particles of 10-nm diameter or larger originating from the Reticle Zone and from plenum surfaces contaminated by exposure to the Reticle Zone. Protection is achieved with negligible effect on EUV transmission. Furthermore, the bottom showerhead efficiently protects the reticle from nanoscale particles originating from the Optics Zone.

36 MATERIALS SCIENCE↗

DOE OSTI2011

EVALUATION OF ALTERNATIVE FILTER MEDIA FOR THE ROTARY MICROFILTER

SRS is currently developing and testing several processes to treat high level radioactive liquid waste. These processes include the Integrated Salt Disposition Process (ISDP), the Salt Waste Processing Facility (SWPF), and the Small Column Ion Exchange Process (SCIX). Each of these processes has a solid-liquid separation process that limits its throughput. SRNL researchers identified and tested the rotary microfilter as a technology to increase solid-liquid separation throughput. The testing showed significant improvement in filter flux with the rotary microfilter over the baseline crossflow filter (i.e., 2.5-6.5X during scoping tests, as much as 10X in actual waste tests, and approximately 3X in pilot-scale tests). SRNL received funding from DOE EM-21, and subsequently DOE EM-31 to develop the rotary microfilter for high level radioactive service. The work has included upgrading the rotary microfilter for radioactive service, testing with simulated SRS waste streams, and testing it with simulated Hanford waste streams. While the filtration rate is better than that obtained during testing of crossflow filters, the authors believe the rotary microfilter throughput can be improved by using a better filter membrane. The rotary microfilter membrane is made of stainless steel (Pall PMM050). Previous testing, funded by DOE EM-21, showed that asymmetric filters composed of a ceramic membrane on top of a stainless steel support produced higher filter flux than 100% stainless steel symmetric filters in crossflow filter tests. In that testing, the Pall Accusep and Graver filters produced 13-21% larger filter flux than the baseline 0.1 {micro}m Mott filter. While the improvement in flux is not as dramatic as the improvement of the rotary filter over a crossflow filter, a 13-21% increase could reduce the lifetime of a 30 year process by 4-6 years, with significant cost savings. Subsequent rotary filter testing showed the Pall PMM050 stainless steel filter membrane produced higher flux than the Mott filter media in bench-scale and pilot-scale testing. The Accusep and Graver filter media were not evaluated in that testing, because they are not available as flat sheets. The Accusep filter was developed at ORNL and licensed to Pall Corporation. This filter has a stainless steel support structure with a zirconium oxide ceramic membrane. The pore size is 0.1 {micro}m absolute. The Graver filter has a stainless steel support structure with a titanium dioxide ceramic membrane. The pore size is 0.07 {micro}m absolute. SRNL and ORNL are working together to develop filter media similar to the Accusep and Graver media, and to test them in a bench-scale filtration apparatus to attempt to improve the throughput of the rotary microfilter. This report describes the effort.

36 MATERIALS SCIENCE↗

DOE OSTI2017

Advanced, Energy-Efficient Hybrid Membrane System for Industrial Water Reuse

In the U.S. manufacturing sector, current industrial water use practices are energy-intensive and utilize and discharge high volumes of waters, rendering them not sustainable especially in light of the growing scarcity of suitable water supplies. To help address this problem, the goal of this project was to develop an advanced, cost-effective, hybrid membrane-based water treatment system that can improve the energy efficiency of industrial wastewater treatment while allowing at least 50% water reuse efficiency. This hybrid process would combine emerging Forward Osmosis (FO) and Membrane Distillation (MD) technology components into an integrated FO-MD system that can beneficially utilize low-grade waste heat (i.e., T < 450 °F) in industrial facilities to produce distilled-quality product water for reuse. In this project, laboratory-, bench-, and pilot-scale experiments on the hybrid FO-MD system were conducted for industrial wastewater treatment. It was demonstrated at laboratory, bench, and pilot scales that FO-MD membrane technology can concentrate brine to very high total dissolved solids (TDS) levels (>200,000 ppm) that are at least 2.5 times higher than the TDS level to which RO can achieve. In laboratory testing, currently available FO and MD membranes were tested to select for high-performing membranes with high salt rejection and high water flux. Multiple FO membrane/draw-salt solution combinations that gave high water flux with higher than 98% salt rejection were also identified. Reverse draw-salt fluxes were observed to be much lower for divalent salts than for monovalent salts. MD membranes were identified that had 99.9+% salt rejection and water flux as high as 50-90 L/(m 2 ·h) for flat-sheet membranes and >20 L/(m 2 ·h) for hollow fibers. In bench-scale testing, a single unit of commercially available FO and MD membrane modules were evaluated for continuous, integrated operation. Using the laboratory- and bench-scale test data, numerical modeling was performed on the FO and MD processes to estimate engineering parameters for a larger-scale pilot unit. Based on the experimental studies and modeling results, a pilot-scale, integrated FO-MD prototype unit was designed and built for trailer-mounted operation. This prototype system was fed real industrial wastewater, which could not be further treated by conventional technologies, from an oil production facility and was successfully operated for over 15 weeks without major stoppage. About 90% water recovery was possible, while concentrating the TDS from 12,000 ppm up to 190,500 ppm. The FO-MD prototype rejected most wastewater contaminants while producing water with <300 ppm TDS, even when the feed TDS was higher than 150,000 ppm. No chemical cleaning was necessary during the pilot testing period. Flushing the system with dechlorinated tap water was sufficient to reset the membranes for the next set of test conditions. Pilot performance and membrane autopsy showed that, even though the feed was concentrated more than 10 times, membrane fouling was unnoticeable and no defects were detected on the FO and MD membrane surfaces. This project demonstrated the technical feasibility of the hybrid FO-MD process by taking water already treated to the limit with the highest level of current technologies and further concentrating it 10-fold by using mostly low-cost materials. Because no membranes suitable for full-scale plant applications are available at present, economical feasibility of the hybrid technology is still uncertain, but it is expected that broader industry participation can further reduce FO-MD process costs.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗

DOE OSTI2023

Membrane Adsorbents Comprising Self-Assembled Inorganic Nanocages (SINCs) for Super-fast Direct Air Capture Enabled by Passive Cooling

The objectives of the proposed project were to develop highly porous membrane adsorbents comprising CO 2 -philic polymers and self-assembled inorganic nanocages (SINCs) for rapid temperature swing adsorption using electricity-free solar heating and radiative cooling, enabling an economically viable approach for direct air capture (DAC). Our core technical activities combine three key innovations. (1) Highly porous flat-sheet membrane adsorbents contain CO 2 -philic amines that can be easily produced using a phase inversion method. (2) CO 2 -philic SINCs can be easily dispersed in the polymers with great stability (compared with the metal-organic frameworks or MOFs). (3) The adsorption and desorption are integrated with solar heating and radiative cooling for rapid continuous operation, in contrast to traditional long-cycle separate operation. The membrane adsorbents containing amines, polymers, and SINCs were produced using a one-step industrial process. The porous membranes coupled with porous SINCs offer low resistance for gas flow and fast CO 2 sorption/desorption cycles, while the incorporation of the additional amine groups provides high CO 2 sorption capacity. The key achievements are summarized below. (1) Membrane adsorbents with high PEI loading (>40%), high porosity of >80%, and low gasflow resistance were prepared in one step using commercially available, low-cost materials. (2) Membrane adsorbents based on Solupor and PEI show CO 2 sorption capacity of >1.5 mmol/g using air containing 400 ppm at a relative humidity of 15%. (3) Effect of the adsorbent compositions (such as PEI type, PEI content, SINC content, porosity) on the CO 2 sorption was systematically investigated. (4) Effect of the processing conditions (such as CO 2 content, temperature, and relative humidity) on the CO 2 sorption was systematically investigated; (5) The stability of the membrane adsorption against many cycles of sorption and desorption was studied. The higher molecular weight of PEI (PEI25k) shows better stability than PEI800. (6) Advanced materials with radiative cooling were developed, which can decrease the temperature by 5-7 °C compared to the ambient temperature. (7) Preliminary techno-economic analysis shows that our process may achieve a capture cost of $1,343/tonne CO 2 with a total OPEX cost of $1,112/tonne CO 2 . The adsorbent replacement cost accounted for 52% of the total OPEX cost. Membrane adsorbents with lower costs and longer operation life can significantly decrease the cost. The proposed project directly addresses the requirement of DE-FOA-0002188, i.e., novel materials with CO 2 adsorption capacity for direct air capture with integrated solar heating and radiative cooling to reduce the cost of the DAC. Our future work will focus on the development of low-cost adsorbents that can be stable at the sorption and desorption conditions for long term.

14 SOLAR ENERGY↗

DOE OSTI2024

CFD Modeling of High-Flux Plate-and-Frame Membrane modules for industrial carbon capture

In this work, we explore the use of CO2-selective flat sheet membranes for capturing CO2 from point sources. We employ Computational Fluid Dynamics (CFD) models to design high-flux plate-and-frame membrane modules to achieve uniform flow distribution among membrane elements, minimize dead-end zones, and ease the common concentration polarization issue for gas separation membranes. The goal is to drive membrane technology improvements by providing better module designs for given membrane properties and operating conditions.

Dosso, Cheick↗

DOE OSTI2012

High-Surface-Area Inorganic Membrane for Process Water Removal: Application to Ethanol Fuel Production

This report summarizes process research results about concept development of thin flat sheet water-selective molecular sieve membrane – a breakthrough membrane product technology for separation of water from ethanol-enriched process streams. The studies include 1) membrane separation performance testing with real-world feeds sampled from Pacific Ethanol Inc’s ethanol plant at Boardman, Oregon and 2) process design and simulation of membrane separation implementation into a corn ethanol plant. The separation tests were conducted on a laboratory-bench testing apparatus in a batch operation mode with small membrane samples (about 1-inch diameter) but under practical conditions, while the process simulation was performed using ASPEN and USDA models. A two-stage membrane separation system is proposed to conduct ethanol enrichment and purification by replacing respective distillation and adsorption process. More than 90% energy saving can be obtained using the membrane separation. It is estimated that the membrane unit for a 40 million gal/year of ethanol plant can be fairly compact - about the sizes of a plate heat exchanger due to high flux of the new membrane. The cost and lifetime of this new membrane product are critical factors to lower the capital cost. This membrane technology is promising for upgrading of existing corn ethanol plants and for building of new cellulosic ethanol plants in the future as well. The results obtained in this work warrant further development of membrane module prototypes and demonstration of their long-term operation stability with slip streams at ethanol plants, which is necessary to move the technology toward commercialization.

09 BIOMASS FUELS↗

DOE OSTI2024

Optimization of Membrane-based Carbon Capture using Dimensional Analysis, CFD and Process System Engineering

Carbon capture is a promising option to mitigate CO2 emissions from existing coal-fired power plants, cement and steel industries, and petrochemical complexes. Among the available technologies, membrane-based carbon capture presents the lowest energy consumption, operating costs, and carbon footprint. In addition, membrane processes have important operational flexibil-ity and response times. On the other hand, the major challenges to widespread application of this technology are related to reducing capital costs and improving membrane stability and durability.To upscale the technology into stacked flat sheet configurations, high fidelity computational fluid dynamics (CFD) that describes the separation process accurately are required. High fidelity simulations have been shown to be effective in studying the complex transport phenomena in membrane systems. In addition, obtaining high CO2 recovery percentages and product purity requires a multi-stage membrane process, where the optimal network configuration of the membrane modules must be studied in a systematic way. In order to address the design problem at process scale, we formulate a superstructure for the membrane-based carbon capture, including up to three separation stages. In the formulation of the optimization problem, we include reduced models, based on rigorous CFD simulations of the membrane modules. Numerical results indicate that the optimal design includes three membrane stages, and the capture cost is 45.4 $/t-CO2.

Pedrozo, Hector A.↗

DOE OSTI2024

CFD Modeling of High-Flux Plate-and-Frame Membrane Modules for Industrial Carbon Capture

Dosso, Cheick↗

DOE OSTI2024

Membrane-based Carbon Capture Process Optimization using CFD Modeling

Carbon capture is a promising option to mitigate CO2 emissions from existing coal-fired power plants, cement and steel industries, and petrochemical complexes. Among the available technologies, membrane-based carbon capture presents the lowest energy consumption, operating costs, and carbon footprint. In addition, membrane processes have important operational flexibility and response times. On the other hand, the major challenges to widespread application of this technology are related to reducing capital costs and improving membrane stability and durability. To upscale the technology into stacked flat sheet configurations, high fidelity computational fluid dynamics (CFD) that describes the separation process accurately are required. High fidelity simulations have been shown to be effective in studying the complex transport phenomena in membrane systems. In addition, obtaining high CO2 recovery percentages and product purity re-quires a multi-stage membrane process, where the optimal network configuration of the mem-brane modules must be studied in a systematic way. In order to address the design problem at process scale, we formulate a superstructure for the membrane-based carbon capture, including up to three separation stages. In the formulation of the optimization problem, we include reduced models, based on rigorous CFD simulations of the membrane modules.

Pedrozo, Hector A.↗

DOE OSTI2025

Scalable and Regenerable Fibrous Amine-functionalized Matrix (FAM) sorbent for Efficient Enrichment of Critical Minerals from Coal Wastewaters

The poster presents the latest progress on utilizing a commercially scalable flat sheet sorbent for the effective enrichment of critical minerals from coal wastewater. It highlights the performance, scalability, and potential for industrial applications, addressing key challenges in critical recovery from complex wastewater streams.

critical metals↗

DOE OSTI2021

Effect of Polyphenylsulfone and Polysulfone Incompatibility on the Structure and Performance of Blend Membranes for Ultrafiltration

This study deals with the modification of polyphenylsulfone ultrafiltration membranes by introduction of an incompatible polymer polysulfone to the polyphenylsulfone casting solution to improve the permeability. The correlation between properties of the blend polyphenylsulfone/polysulfone solutions and porous anisotropic membranes for ultrafiltration prepared from these solutions was revealed. The blend polyphenylsulfone/polysulfone solutions were investigated using a turbidity spectrum method, optical microscopy and measurements of dynamic viscosity and turbidity. The structure of the prepared blend flat sheet membranes was studied using scanning electron microscopy. Membrane separation performance was investigated in the process of ultrafiltration of human serum albumin buffered solutions. It was found that with the introduction of polysulfone to the polyphenylsulfone casting solution in N-methyl-2-pyrrolidone the size of supramolecular particles significantly increases with the maximum at (40–60):(60:40) polyphenylsulfone:polysulfone blend ratio from 76 nm to 196–354 nm. It was shown that polyphenylsulfone/polysulfone blend solutions, unlike the solutions of pristine polymers, are two-phase systems (emulsions) with the maximum droplet size and highest degree of polydispersity at polyphenylsulfone/polysulfone blend ratios (30–60):(70–40). Pure water flux of the blend membranes passes through a maximum in the region of the most heterogeneous structure of the casting solution, which is associated with the imposition of a polymer-polymer phase separation on the non-solvent induced phase separation upon membrane preparation. The application of polyphenylsulfone/polysulfone blends as membrane-forming polymers and polyethylene glycol (Mn = 400 g·mol -1 ) as a pore-forming agent to the casting solutions yields the formation of ultrafiltration membranes with high membrane pure water flux (270 L·m -2 ·h -1 at 0.1MPa) and human serum albumin rejection of 85%.

36 MATERIALS SCIENCE↗

NASA NTRS1971

Foldable patterns form construction blocks

Building blocks with interlocking tabs can be constructed from flat sheets of material using minimum of tools and equipment. Blocks can be used for storing and shipping supplies to remote areas, then filled with soil and stacked to form inhabitable structures which can be dismantled and reused.

Huber, W. C.↗

NASA NTRS1972

Hailstone impact simulator.

The hailstone impact simulator was constructed to provide experimental data in support of a program to develop the analytical methods for predicting hail damage to aircraft structures. This paper describes the simulator, its operation, the type of data obtained, and the resulting damage by individual hailstones to metallic flat sheets and spherical caps. Simulated hailstones of 1.3, 2.5, 3.8, and 5.1 cm in diameter were used at impact velocities of 60 to 600 m/s.

Alfaro-Bou, E.↗