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At least 1,495 records · Page 83
All sourcesNASA NTRSDOE OSTI
NASA NTRS2013

A Parameter Estimation Scheme for Multiscale Kalman Smoother (MKS) Algorithm Used in Precipitation Data Fusion

A new approach is presented in this paper to effectively obtain parameter estimations for the Multiscale Kalman Smoother (MKS) algorithm. This new approach has demonstrated promising potentials in deriving better data products based on data of different spatial scales and precisions. Our new approach employs a multi-objective (MO) parameter estimation scheme (called MO scheme hereafter), rather than using the conventional maximum likelihood scheme (called ML scheme) to estimate the MKS parameters. Unlike the ML scheme, the MO scheme is not simply built on strict statistical assumptions related to prediction errors and observation errors, rather, it directly associates the fused data of multiple scales with multiple objective functions in searching best parameter estimations for MKS through optimization. In the MO scheme, objective functions are defined to facilitate consistency among the fused data at multiscales and the input data at their original scales in terms of spatial patterns and magnitudes. The new approach is evaluated through a Monte Carlo experiment and a series of comparison analyses using synthetic precipitation data. Our results show that the MKS fused precipitation performs better using the MO scheme than that using the ML scheme. Particularly, improvements are significant compared to that using the ML scheme for the fused precipitation associated with fine spatial resolutions. This is mainly due to having more criteria and constraints involved in the MO scheme than those included in the ML scheme. The weakness of the original ML scheme that blindly puts more weights onto the data associated with finer resolutions is overcome in our new approach.

multiscale↗
NASA NTRS2017

Experimental Observations of Nuclear Activity in Deuterated Materials Subjected to a Low-Energy Photon Beam

Exposure of highly deuterated materials to a low-energy (nom. 2 MeV) photon beam resulted in nuclear activity of both the parent metals of hafnium and erbium and a witness material (molybdenum) mixed with the reactants. Gamma spectral analysis of all deuterated materials, ErD2.8+C36D74+Mo and HfD2+C36D74+Mo, showed that nuclear processes had occurred as shown by unique gamma signatures. For the deuterated erbium specimens, posttest gamma spectra showed evidence of radioisotopes of erbium ((163)Er and (171)Er) and of molybdenum ((99)Mo and (101)Mo) and by beta decay, technetium (99mTc and 101Tc). For the deuterated hafnium specimens, posttest gamma spectra showed evidence of radioisotopes of hafnium (180mHf and 181Hf) and molybdenum ((99)Mo and (101)Mo), and by beta decay, technetium ((99m)Tc and (101)Tc). In contrast, when either the hydrogenated or non-gas-loaded erbium or hafnium materials were exposed to the gamma flux, the gamma spectra revealed no new isotopes. Neutron activation materials showed evidence of thermal and epithermal neutrons. CR-39 solid-state nuclear track detectors showed evidence of fast neutrons with energies between 1.4 and 2.5 MeV and several instances of triple tracks, indicating (is) greater than 10 MeV neutrons. Further study is required to determine the mechanism causing the nuclear activity.

Steinetz, Bruce M.↗
DOE OSTI2023

Cathodes and electrolytes for rechargeable magnesium batteries and methods of manufacture

The invention relates to Chevrel-phase materials and methods of preparing these materials utilizing a precursor approach. The Chevrel-phase materials are useful in assembling electrodes, e.g., cathodes, for use in electrochemical cells, such as rechargeable batteries. The Chevrel-phase materials have a general formula of Mo 6 Z 8 (Z=sulfur) or Mo 6 Z 1 8-yZ 2 y (Z 1 =sulfur; Z 2 =selenium), and partially cuprated Cu 1 Mo 6 S 8 as well as partially de-cuprated Cu 1-x Mg x Mo 6 S 8 and the precursors have a general formula of M x Mo 6 Z 8 or M x Mo 6 Z 1 8-yZ 2 y , M=Cu. The cathode containing the Chevrel-phase material in accordance with the invention can be combined with a magnesium-containing anode and an electrolyte.

Kumta, Prashant N.↗
DOE OSTI2020

Investigating the compressive strength and strain localization of nanotwinned nickel alloys

Sputter deposited nickel-molybdenum-tungsten (Ni-Mo-W) thin films possess a beneficial suite of properties that stem from the extremely fine growth twins that form during the deposition process. Previously these materi- als were only characterized in tension, however, in this study in situ micropillar compression and post-mortem microstructural analysis of nanotwinned Ni 84 Mo 11 W 5 micropillars were employed to measure the compressive response and elucidate the attendant deformation mechanisms. The pillars exhibit Hookean behavior to com- pressive strengths of 3-3.5 GPa and the onset of non-linear plastic flow was manifest by discrete strain bursts and highly localized shear bands. Plastic deformation was concentrated at the top of the pillar, while the bulk of the micropillar was nominally unaffected. Post-mortem investigations indicate that at sufficiently high stresses shear banding is triggered, resulting in intense and highly localized plastic deformation that led to the formation of twin-free nanocrystalline grains within highly deformed shear bands. By contrast, the regions adjacent to the shear bands were unaffected. The absence of detwinning and dislocation glide mechanisms was unexpected and in direct contrast to what has been observed in nanotwinned Cu-Al. Post-mortem observations of the Ni-Mo-W micropillars suggest that the ultrafine twins create a unique form of dislocation starvation and source-limited plasticity. The ultrahigh compressive strength is governed by the triggering of shear bands rather than the activa- tion of dislocation glide. Finally, the specialized nature of plasticity in nanotwinned Ni-Mo-W is clear, even though the precise trigger for shear band formation in nanotwinned Ni-Mo-W remains to be identified.

36 MATERIALS SCIENCE↗
DOE OSTI2025

Comparison of the earliest NC and CC planetesimals: Evidence from ungrouped iron meteorites

Isotope anomalies in meteorites reveal a fundamental dichotomy between Non-Carbonaceous- (NC) and Carbonaceous-type (CC) planetary bodies. Until now, this dichotomy is established for the major meteorite groups, representing about 36 distinct parent bodies. Ungrouped meteorites represent an even larger number of additional parent bodies, but whether they conform to the overall NC-CC dichotomy is unknown. Here, the genetics and chronology of 26 ungrouped iron meteorites are considered through nucleosynthetic Mo and radiogenic W isotopic compositions. Secondary cosmic ray-induced modifications of these isotope compositions are corrected using Pt isotope measurements on the same samples. We find that all of the ungrouped irons have Mo isotope anomalies within the range of the major meteorite groups and confirm the NC-CC dichotomy for Mo, where NC and CC meteorites define two distinct, subparallel s-process mixing lines. All ungrouped NC irons fall on the NC-line, which is now precisely defined for 41 distinct parent bodies. The ungrouped CC irons show scatter around the CC-line indicative of small r-process Mo heterogeneities among these samples. These r-process Mo isotope variations correlate with O isotope anomalies, most likely reflecting mixing of CI chondrite-like matrix, chondrule precursors, and Ca-Al-rich inclusions. This implies that CC iron meteorite parent bodies accreted the same nebular components as the later-formed carbonaceous chondrites. The Hf-W model ages of core formation for the ungrouped irons overlap with those of the iron meteorite groups from each reservoir and reveal a narrow age peak at ∼3.3 Ma after Ca-Al-rich inclusions for the CC irons. By contrast, the NC irons display more variable ages, including younger ages indicative of impact-induced melting events, which seem absent among the CC irons. This is attributed to the more fragile and porous nature of the CC bodies, making impact-induced melting on their surfaces difficult. The chemical characteristics of all iron meteorites together reveal slightly more oxidizing conditions during core formation for CC compared to NC irons. More strikingly, strong depletions in moderately volatile elements, typical of many iron meteorite parent bodies, predominantly occur among CC irons, for reasons that remain unclear at present.

Chondrite components↗
DOE OSTI2022

An investigation of the failure modes in U-10Mo monolithic fuel irradiated to high burnup

Here, this study investigated possible failure mode sequences in U-10Mo monolithic fuel irradiated to very-high-burnup. The U-Mo fuel plate used in this study was characterized using scanning electron microscopy (SEM), wavelength dispersive spectroscopy (WDS), and image analysis techniques to investigate how microstructural features may initiate crack formation and propagation through the microstructure, potentially leading to blistering. Distinctly large fission gas pores (FGPs) were observed to preferentially align 5-15µm away from the U-10Mo/Zr interface, parallel to the Zr diffusion barrier. Preferential growth, alignment, and interconnection of FGP could initiate blistering in the fuel plate by creating a fission gas channel, parallel to the U-Mo/Zr interface. FGP alignment in the fuel phase near the U-Mo/Zr interface is believed to be one of the precursors to crack and Type 2 blister formation in monolithic U-Mo fuels. The chemical maps revealed differences in fission product behavior near the U-Mo/Zr interface such that Nd remains in the fuel matrix at the FGP sites. On the other hand, other fission products like Xe and Cs can get trapped in FGPs by Nd in the fuel phase and/or diffuse toward the Zr diffusion barrier.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2020

Materials Data on Lu6Sb2Mo by Materials Project

Lu6MoSb2 crystallizes in the hexagonal P-62m space group. The structure is three-dimensional. there are two inequivalent Lu sites. In the first Lu site, Lu is bonded in a 5-coordinate geometry to one Mo and four equivalent Sb atoms. The Lu–Mo bond length is 3.12 Å. All Lu–Sb bond lengths are 3.27 Å. In the second Lu site, Lu is bonded to two equivalent Mo and two equivalent Sb atoms to form a mixture of distorted corner and edge-sharing LuSb2Mo2 tetrahedra. Both Lu–Mo bond lengths are 2.88 Å. Both Lu–Sb bond lengths are 3.11 Å. Mo is bonded in a 9-coordinate geometry to nine Lu atoms. Sb is bonded in a 9-coordinate geometry to nine Lu atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on GaTe4(MoSe)4 by Materials Project

GaMo4Se4Te4 crystallizes in the cubic F-43m space group. The structure is three-dimensional. Mo+3.25+ is bonded in a 3-coordinate geometry to three equivalent Te2- and three equivalent Se2- atoms. All Mo–Te bond lengths are 2.94 Å. All Mo–Se bond lengths are 2.50 Å. Ga3+ is bonded in a tetrahedral geometry to four equivalent Te2- atoms. All Ga–Te bond lengths are 2.58 Å. Te2- is bonded in a 1-coordinate geometry to three equivalent Mo+3.25+ and one Ga3+ atom. Se2- is bonded in a 12-coordinate geometry to three equivalent Mo+3.25+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Be2Mo by Materials Project

Be2Mo is Hexagonal Laves structured and crystallizes in the hexagonal P6_3/mmc space group. The structure is three-dimensional. there are two inequivalent Be sites. In the first Be site, Be is bonded to six equivalent Be and six equivalent Mo atoms to form a mixture of corner, edge, and face-sharing BeBe6Mo6 cuboctahedra. All Be–Be bond lengths are 2.24 Å. All Be–Mo bond lengths are 2.61 Å. In the second Be site, Be is bonded to six Be and six equivalent Mo atoms to form a mixture of corner, edge, and face-sharing BeBe6Mo6 cuboctahedra. There are two shorter (2.19 Å) and two longer (2.26 Å) Be–Be bond lengths. All Be–Mo bond lengths are 2.61 Å. Mo is bonded in a 12-coordinate geometry to twelve Be atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Al2Mo3C by Materials Project

Mo3Al2C crystallizes in the cubic P4_132 space group. The structure is three-dimensional. Mo is bonded in a distorted bent 150 degrees geometry to six equivalent Al and two equivalent C atoms. There are four shorter (2.84 Å) and two longer (2.93 Å) Mo–Al bond lengths. Both Mo–C bond lengths are 2.16 Å. Al is bonded to nine equivalent Mo and three equivalent Al atoms to form AlAl3Mo9 cuboctahedra that share corners with fifteen equivalent AlAl3Mo9 cuboctahedra, edges with three equivalent CMo6 octahedra, faces with ten equivalent AlAl3Mo9 cuboctahedra, and faces with four equivalent CMo6 octahedra. All Al–Al bond lengths are 2.56 Å. C is bonded to six equivalent Mo atoms to form distorted CMo6 octahedra that share corners with six equivalent CMo6 octahedra, edges with six equivalent AlAl3Mo9 cuboctahedra, and faces with eight equivalent AlAl3Mo9 cuboctahedra. The corner-sharing octahedral tilt angles are 25°.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Y5(MoO6)2 by Materials Project

Y5Mo2O12 crystallizes in the monoclinic C2/m space group. The structure is three-dimensional. there are three inequivalent Y3+ sites. In the first Y3+ site, Y3+ is bonded to six O2- atoms to form YO6 octahedra that share corners with four equivalent MoO6 octahedra, corners with four equivalent YO7 pentagonal bipyramids, and edges with two equivalent YO7 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 39°. There are two shorter (2.23 Å) and four longer (2.34 Å) Y–O bond lengths. In the second Y3+ site, Y3+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of Y–O bond distances ranging from 2.30–2.52 Å. In the third Y3+ site, Y3+ is bonded to seven O2- atoms to form distorted YO7 pentagonal bipyramids that share corners with two equivalent YO6 octahedra, an edgeedge with one YO6 octahedra, edges with two equivalent MoO6 octahedra, and edges with two equivalent YO7 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 56°. There are a spread of Y–O bond distances ranging from 2.30–2.47 Å. Mo+4.50+ is bonded to six O2- atoms to form MoO6 octahedra that share corners with two equivalent YO6 octahedra, edges with two equivalent MoO6 octahedra, and edges with two equivalent YO7 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 39°. There are a spread of Mo–O bond distances ranging from 1.95–2.14 Å. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded to two Y3+ and two equivalent Mo+4.50+ atoms to form distorted OY2Mo2 trigonal pyramids that share corners with eight OY4 tetrahedra, edges with four equivalent OY3Mo tetrahedra, and an edgeedge with one OY2Mo2 trigonal pyramid. In the second O2- site, O2- is bonded in a 3-coordinate geometry to one Y3+ and two equivalent Mo+4.50+ atoms. In the third O2- site, O2- is bonded to four Y3+ atoms to form OY4 tetrahedra that share corners with ten OY4 tetrahedra, corners with three equivalent OY2Mo2 trigonal pyramids, and edges with four OY4 tetrahedra. In the fourth O2- site, O2- is bonded to three Y3+ and one Mo+4.50+ atom to form distorted OY3Mo tetrahedra that share corners with ten OY4 tetrahedra, a cornercorner with one OY2Mo2 trigonal pyramid, edges with three OY4 tetrahedra, and edges with two equivalent OY2Mo2 trigonal pyramids.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on PrSi2Mo2C by Materials Project

PrMo2Si2C crystallizes in the tetragonal P4/mmm space group. The structure is three-dimensional. Pr3+ is bonded in a distorted linear geometry to eight equivalent Si4- and two equivalent C4- atoms. All Pr–Si bond lengths are 3.23 Å. Both Pr–C bond lengths are 2.72 Å. Mo+4.50+ is bonded to four equivalent Si4- and two equivalent C4- atoms to form a mixture of distorted face, edge, and corner-sharing MoSi4C2 octahedra. The corner-sharing octahedral tilt angles are 0°. All Mo–Si bond lengths are 2.60 Å. Both Mo–C bond lengths are 2.12 Å. Si4- is bonded in a 9-coordinate geometry to four equivalent Pr3+, four equivalent Mo+4.50+, and one Si4- atom. The Si–Si bond length is 2.42 Å. C4- is bonded to two equivalent Pr3+ and four equivalent Mo+4.50+ atoms to form corner-sharing CPr2Mo4 octahedra. The corner-sharing octahedral tilt angles are 0°.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on HfSiMo by Materials Project

MoSiHf is delta Molybdenum Boride-derived structured and crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. Hf is bonded in a 9-coordinate geometry to four equivalent Mo and five equivalent Si atoms. There are two shorter (2.97 Å) and two longer (3.08 Å) Hf–Mo bond lengths. There are a spread of Hf–Si bond distances ranging from 2.74–2.91 Å. Mo is bonded in a 12-coordinate geometry to four equivalent Hf and four equivalent Si atoms. There are a spread of Mo–Si bond distances ranging from 2.52–2.69 Å. Si is bonded in a 9-coordinate geometry to five equivalent Hf and four equivalent Mo atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on MoPRu by Materials Project

MoRuP crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. Mo is bonded in a 3-coordinate geometry to six equivalent Ru and five equivalent P atoms. There are a spread of Mo–Ru bond distances ranging from 2.86–2.89 Å. There are a spread of Mo–P bond distances ranging from 2.43–2.79 Å. Ru is bonded in a 12-coordinate geometry to six equivalent Mo, two equivalent Ru, and four equivalent P atoms. Both Ru–Ru bond lengths are 2.76 Å. There are a spread of Ru–P bond distances ranging from 2.30–2.42 Å. P is bonded in a 9-coordinate geometry to five equivalent Mo and four equivalent Ru atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Mo3S3Br by Materials Project

Mo3S3Br crystallizes in the trigonal R-3 space group. The structure is three-dimensional. Mo+2.33+ is bonded to four equivalent S2- and one Br1- atom to form a mixture of edge and corner-sharing MoS4Br square pyramids. There are a spread of Mo–S bond distances ranging from 2.41–2.51 Å. The Mo–Br bond length is 2.65 Å. S2- is bonded in a 4-coordinate geometry to four equivalent Mo+2.33+ atoms. Br1- is bonded in a 6-coordinate geometry to three equivalent Mo+2.33+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Be22Mo by Materials Project

Be22Mo crystallizes in the cubic Fd-3m space group. The structure is three-dimensional. there are four inequivalent Be sites. In the first Be site, Be is bonded to twelve Be atoms to form a mixture of face, edge, and corner-sharing BeBe12 cuboctahedra. There are six shorter (2.05 Å) and six longer (2.25 Å) Be–Be bond lengths. In the second Be site, Be is bonded in a distorted linear geometry to twelve equivalent Be and two equivalent Mo atoms. All Be–Be bond lengths are 2.46 Å. Both Be–Mo bond lengths are 2.50 Å. In the third Be site, Be is bonded to twelve Be atoms to form a mixture of distorted face, edge, and corner-sharing BeBe12 cuboctahedra. There are a spread of Be–Be bond distances ranging from 2.19–2.29 Å. In the fourth Be site, Be is bonded to eleven Be and one Mo atom to form a mixture of face, edge, and corner-sharing BeBe11Mo cuboctahedra. There are a spread of Be–Be bond distances ranging from 2.14–2.35 Å. The Be–Mo bond length is 2.54 Å. Mo is bonded in a 4-coordinate geometry to sixteen Be atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ni2Mo3N by Materials Project

Ni2Mo3N crystallizes in the cubic P4_132 space group. The structure is three-dimensional. Mo is bonded in a bent 150 degrees geometry to six equivalent Ni and two equivalent N atoms. There are a spread of Mo–Ni bond distances ranging from 2.74–2.83 Å. Both Mo–N bond lengths are 2.09 Å. Ni is bonded to nine equivalent Mo and three equivalent Ni atoms to form NiNi3Mo9 cuboctahedra that share corners with fifteen equivalent NiNi3Mo9 cuboctahedra, edges with three equivalent NMo6 octahedra, faces with ten equivalent NiNi3Mo9 cuboctahedra, and faces with four equivalent NMo6 octahedra. All Ni–Ni bond lengths are 2.48 Å. N is bonded to six equivalent Mo atoms to form distorted NMo6 octahedra that share corners with six equivalent NMo6 octahedra, edges with six equivalent NiNi3Mo9 cuboctahedra, and faces with eight equivalent NiNi3Mo9 cuboctahedra. The corner-sharing octahedral tilt angles are 26°.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ag6Mo10O33 by Materials Project

Ag6Mo10O33 crystallizes in the triclinic P-1 space group. The structure is three-dimensional. there are five inequivalent Mo6+ sites. In the first Mo6+ site, Mo6+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Mo–O bond distances ranging from 1.75–2.30 Å. In the second Mo6+ site, Mo6+ is bonded in a 4-coordinate geometry to six O2- atoms. There are a spread of Mo–O bond distances ranging from 1.75–2.51 Å. In the third Mo6+ site, Mo6+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Mo–O bond distances ranging from 1.76–2.45 Å. In the fourth Mo6+ site, Mo6+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Mo–O bond distances ranging from 1.74–2.30 Å. In the fifth Mo6+ site, Mo6+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Mo–O bond distances ranging from 1.74–2.40 Å. There are three inequivalent Ag1+ sites. In the first Ag1+ site, Ag1+ is bonded in a 4-coordinate geometry to five O2- atoms. There are a spread of Ag–O bond distances ranging from 2.22–2.92 Å. In the second Ag1+ site, Ag1+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Ag–O bond distances ranging from 2.30–3.03 Å. In the third Ag1+ site, Ag1+ is bonded in a distorted trigonal bipyramidal geometry to five O2- atoms. There are a spread of Ag–O bond distances ranging from 2.34–2.71 Å. There are seventeen inequivalent O2- sites. In the first O2- site, O2- is bonded in a 3-coordinate geometry to three Mo6+ atoms. In the second O2- site, O2- is bonded in a 3-coordinate geometry to three Mo6+ atoms. In the third O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Mo6+ and one Ag1+ atom. In the fourth O2- site, O2- is bonded in a linear geometry to one Mo6+ and one Ag1+ atom. In the fifth O2- site, O2- is bonded to three Mo6+ and one Ag1+ atom to form a mixture of distorted corner and edge-sharing OAgMo3 tetrahedra. In the sixth O2- site, O2- is bonded to three Mo6+ and one Ag1+ atom to form a mixture of distorted corner and edge-sharing OAgMo3 tetrahedra. In the seventh O2- site, O2- is bonded in a 2-coordinate geometry to one Mo6+ and two Ag1+ atoms. In the eighth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Mo6+ and one Ag1+ atom. In the ninth O2- site, O2- is bonded in a square co-planar geometry to four Mo6+ atoms. In the tenth O2- site, O2- is bonded in a distorted bent 120 degrees geometry to two Mo6+ and one Ag1+ atom. In the eleventh O2- site, O2- is bonded in a distorted trigonal planar geometry to two Mo6+ and one Ag1+ atom. In the twelfth O2- site, O2- is bonded in a distorted linear geometry to one Mo6+ and one Ag1+ atom. In the thirteenth O2- site, O2- is bonded in a 2-coordinate geometry to one Mo6+ and one Ag1+ atom. In the fourteenth O2- site, O2- is bonded in a distorted single-bond geometry to two Mo6+ atoms. In the fifteenth O2- site, O2- is bonded in a 1-coordinate geometry to one Mo6+ and two Ag1+ atoms. In the sixteenth O2- site, O2- is bonded in a 1-coordinate geometry to one Mo6+ and two Ag1+ atoms. In the seventeenth O2- site, O2- is bonded in a distorted single-bond geometry to two Mo6+ and one Ag1+ atom.

36 MATERIALS SCIENCE↗