Search NASA⌕ Search

SEARCH · Search NASA

Results for “MAC”

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 37 records · Page 2
All sourcesNASA NTRSDOE OSTI
NASA NTRS1994

Micromechanics Analysis Code (MAC) User Guide: Version 1.0

The ability to accurately predict the thermomechanical deformation response of advanced composite materials continues to play an important role in the development of these strategic materials. Analytical models that predict the effective behavior of composites are used not only by engineers performing structural analysis of large-scale composite components but also by material scientists in developing new material systems. For an analytical model to fulfill these two distinct functions it must be based on a micromechanics approach which utilizes physically based deformation and life constitutive models and allows one to generate the average (macro) response of a composite material given the properties of the individual constituents and their geometric arrangement. Here the user guide for the recently developed, computationally efficient and comprehensive micromechanics analysis code, MAC, who's predictive capability rests entirely upon the fully analytical generalized method of cells, GMC, micromechanics model is described. MAC is a versatile form of research software that 'drives' the double or triple ply periodic micromechanics constitutive models based upon GMC. MAC enhances the basic capabilities of GMC by providing a modular framework wherein (1) various thermal, mechanical (stress or strain control), and thermomechanical load histories can be imposed; (2) different integration algorithms may be selected; (3) a variety of constituent constitutive models may be utilized and/or implemented; and (4) a variety of fiber architectures may be easily accessed through their corresponding representative volume elements.

Wilt, T. E.↗
NASA NTRS1996

Micromechanics Analysis Code (MAC). User Guide: Version 2.0

The ability to accurately predict the thermomechanical deformation response of advanced composite materials continues to play an important role in the development of these strategic materials. Analytical models that predict the effective behavior of composites are used not only by engineers performing structural analysis of large-scale composite components but also by material scientists in developing new material systems. For an analytical model to fulfill these two distinct functions it must be based on a micromechanics approach which utilizes physically based deformation and life constitutive models and allows one to generate the average (macro) response of a composite material given the properties of the individual constituents and their geometric arrangement. Here the user guide for the recently developed, computationally efficient and comprehensive micromechanics analysis code's (MAC) who's predictive capability rests entirely upon the fully analytical generalized method of cells (GMC), micromechanics model is described. MAC is a versatile form of research software that 'drives' the double or triply periodic micromechanics constitutive models based upon GMC. MAC enhances the basic capabilities of GMC by providing a modular framework wherein (1) various thermal, mechanical (stress or strain control) and thermomechanical load histories can be imposed, (2) different integration algorithms may be selected, (3) a variety of constituent constitutive models may be utilized and/or implemented, and (4) a variety of fiber and laminate architectures may be easily accessed through their corresponding representative volume elements.

Wilt, T. E.↗
NASA NTRS2002

Sunyaev-Zeldovich Effect Imaging of MACS Galaxy Clusters at z greater than 0.5

We present 30 GHz interferometric SZE measurements of a redshift limited, X-ray selected cluster sample from the Massive Cluster Survey (MACS). All eight of the high redshift (z.0.5, dec greater than -15) galaxy clusters were detected. Additional observations were made at 4.8 GHz with the Very Large Array to help constrain the amount of point source contamination to the SZE decrements. From SZE data alone, we derive electron temperatures in the range 5.5-18.5 keV and total masses between 1.5 and 2.6 x 10 circumflex 14 M_sun within a 65 arcsecond radius for the eight clusters. Six of the clusters are MACS discoveries, while two (C10016+1609 and MS 0451.6-0305) were detected by previous X-ray observations and have been recently observed with the Chandra observatory. The X-ray derived temperatures and masses for Cl0016+ 1609 and MS 0451.6-0305 are in good agreement with the SZE-derived values. Strong detections of the SZE signal in this sample of MACS objects confirms that they are hot, massive clusters.

Laroque, S. J.↗
NASA NTRS2003

Sunyaev-Zeldovich Effect Imaging of Macs Galaxy Clusters at =>0.5

We present 30 GHz interferometric Sunyaev-Zeldovich effect (SZE) measurements of a redshift-limited, X-ray-selected cluster sample from the Massive Cluster Survey (MACS). All eight of the high-redshift (z > 0.5, delta > -15 deg) galaxy clusters were detected. Additional observations were made at 4.8 GHz with the Very Large Array to help constrain the amount of point source contamination to the SZE decrements. From SZE data alone, we derive electron temperatures in the range 5.5-18.5 keV and total masses between 1.5 and 2.6 x 10(exp 14)/h solar masses within a 65 minute radius (0.28/h Mpc at z = 0.5) for the eight clusters. Six of the clusters are MACS discoveries, while two (C10016+1609 and MS 0451.6-0305) were detected by previous X-ray observations and have been recently observed with the Chandra observatory. The X-ray-derived temperatures and masses for C10016+1609 and MS 0451.6-0305 are in good agreement with the SZE derived values. Strong detections of the SZE signal in this sample of MACS objects confirm that they are hot, massive clusters.

LaRoque, Samuel↗
NASA NTRS2005

A network architecture for precision formation flying using the IEEE 802.11 MAC Protocol

Precision Formation Flying missions involve the tracking and maintenance of spacecraft in a desired geometric formation. The strong coupling of spacecraft in formation flying control requires inter-spacecraft communication to exchange information. In this paper, we present a network architecture that supports PFF control, from the initial random deployment phase to the final formation. We show that a suitable MAC layer for the application protocol is IEEE's 802.11 MAC protocol. IEEE 802.11 MAC has two modes of operations: DCF and PCF. We show that DCF is suitable for the initial deployment phase while switching to PCF when the spacecraft are in formation improves jitter and throughput. We also consider the effect of routing on protocol performance and suggest when it is profitable to turn off route discovery to achieve better network performance.

precision formation flying↗
DOE OSTI2026

Microscopy and Characterization Suite (MaCS) and National Synchrotron Light Source-II (NSLS-II) FY 2025 Annual Report

The Microscopy and Characterization Suite (MaCS) laboratory at the Critical Materials and Energy Systems Innovation Center (CMESIC), formerly the Center for Advanced Energy Studies (CAES) and the National Synchrotron Light Source-II (NSLS-II) at Brookhaven National Laboratory (BNL) partner with the Nuclear Science User Facilities (NSUF). These partnerships provide funding that allows researchers to access these facilities at no cost for studying irradiation effects on nuclear fuels and materials. Through NSUF, both MaCS and NSLS-II support post-irradiation examination (PIE) and irradiation activities for NSUF Rapid Turnaround Experiments (RTE) and NSUF Consolidated Innovative Nuclear Research (CINR) awards.

36 - MATERIALS SCIENCE↗
DOE OSTI2016

Young galaxy candidates in the Hubble Frontier Fields. III. MACS J0717.5+3745

In this paper we present the results of our search for and study of z≳6 galaxy candidates behind the third Frontier Fields (FFs) cluster, MACS J0717.5+3745, and its parallel field, combining data from Hubble and Spitzer. We select 39 candidates using the Lyman break technique, for which the clear non-detection in optical make the extreme mid-z interlopers hypothesis unlikely. We also take benefit from z≳6 samples selected using the previous FF data sets of Abell 2744 and MACS 0416 to improve the constraints on the properties of very high redshift objects. We compute the redshift and the physical properties such emission lines properties, star formation rate, reddening, and stellar mass for all FF objects from their spectral energy distribution using templates including nebular emission lines. We study the relationship between several physical properties and confirm the trend already observed in previous surveys for evolution of star formation rate with galaxy mass and between the size and the UV luminosity of our candidates. The analysis of the evolution of the UV luminosity function with redshift seems more compatible with an evolution of density. Moreover, no robust z⩾8.5 object is selected behind the cluster field and few z∼9 candidates have been selected in the two previous data sets from this legacy survey, suggesting a strong evolution in the number density of galaxies between z∼8 and 9. Thanks to the use of the lensing cluster, we study the evolution of the star formation rate density produced by galaxies with L > 0.03 L{sup ⋆}, and confirm the strong decrease observed between z∼8 and 9.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2020

A Multiwavelength Study of the Cool Core Cluster MACS J1447.4+0827

Clusters of galaxies are outstanding laboratories for understanding the physics of supermassive black hole (SMBH) feedback. Here we present the first Chandra, Karl G. Jansky Very Large Array, and Hubble Space Telescope analysis of MACS J1447.4+0827 (z = 0.3755), one of the strongest cool core clusters known, in which extreme feedback from its central SMBH is needed to prevent the hot intracluster gas from cooling. Using this multiwavelength approach, including 70 ks of Chandra X-ray observations, we detect the presence of collimated jetted outflows that coincide with a southern and a northern X-ray cavity. The total mechanical power associated with these outflows (P {sub cav} ≈ 6 × 10{sup 44} erg s{sup −1}) is roughly consistent with the energy required to prevent catastrophic cooling of the hot intracluster gas (L {sub cool} = 1.71 ± 0.01 × 10{sup 45} erg s{sup −1} for t {sub cool} = 7.7 Gyr), implying that powerful SMBH feedback was in place several Gyr ago in MACS J1447.7+0827. In addition, we detect the presence of a radio minihalo that extends over 300 kpc in diameter (P {sub 1.4GHz} = 3.0 ± 0.3 × 10{sup 24} W Hz{sup −1}). The X-ray observations also reveal an ∼20 kpc plumelike structure that coincides with optical dusty filaments that surround the central galaxy. Overall, this study demonstrates that the various physical phenomena occurring in the most nearby clusters of galaxies are also occurring in their more distant analogs.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2017

Young Galaxy Candidates in the Hubble Frontier Fields. IV. MACS J1149.5+2223

We search for high-redshift dropout galaxies behind the Hubble Frontier Fields (HFF) galaxy cluster MACS J1149.5+2223, a powerful cosmic lens that has revealed a number of unique objects in its field. Using the deep images from the Hubble and Spitzer space telescopes, we find 11 galaxies at z > 7 in the MACS J1149.5+2223 cluster field, and 11 in its parallel field. The high-redshift nature of the bright z ≃ 9.6 galaxy MACS1149-JD, previously reported by Zheng et al., is further supported by non-detection in the extremely deep optical images from the HFF campaign. With the new photometry, the best photometric redshift solution for MACS1149-JD reduces slightly to z = 9.44 ± 0.12. The young galaxy has an estimated stellar mass of (7±2)×10{sup 8} M{sub ⊙}, and was formed at z=13.2{sub −1.6}{sup +1.9} when the universe was ≈300 Myr old. Data available for the first four HFF clusters have already enabled us to find faint galaxies to an intrinsic magnitude of M{sub UV}≃−15.5, approximately a factor of 10 deeper than the parallel fields.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2017

Joining X-Ray to Lensing: An Accurate Combined Analysis of MACS J0416.1–2403

We present a novel approach for a combined analysis of X-ray and gravitational lensing data and apply this technique to the merging galaxy cluster MACS J0416.1–2403. The method exploits the information on the intracluster gas distribution that comes from a fit of the X-ray surface brightness and then includes the hot gas as a fixed mass component in the strong-lensing analysis. With our new technique, we can separate the collisional from the collision-less diffuse mass components, thus obtaining a more accurate reconstruction of the dark matter distribution in the core of a cluster. We introduce an analytical description of the X-ray emission coming from a set of dual pseudo-isothermal elliptical mass distributions, which can be directly used in most lensing softwares. By combining Chandra observations with Hubble Frontier Fields imaging and Multi Unit Spectroscopic Explorer spectroscopy in MACS J0416.1–2403, we measure a projected gas-to-total mass fraction of approximately 10% at 350 kpc from the cluster center. Compared to the results of a more traditional cluster mass model (diffuse halos plus member galaxies), we find a significant difference in the cumulative projected mass profile of the dark matter component and that the dark matter over total mass fraction is almost constant, out to more than 350 kpc. In the coming era of large surveys, these results show the need of multiprobe analyses for detailed dark matter studies in galaxy clusters.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2019

RELICS: Strong Lensing Analysis of MACS J0417.5–1154 and Predictions for Observing the Magnified High-redshift Universe with JWST

Strong gravitational lensing by clusters of galaxies probes the mass distribution at the core of each cluster and magnifies the universe behind it. MACS J0417.5–1154 at z = 0.443 is one of the most massive clusters known based on weak lensing, X-ray, and Sunyaev–Zel'dovich analyses. In this work we compute a strong lens model of MACS J0417 based on Hubble Space Telescope imaging observations collected, in part, by the Reionization Lensing Cluster Survey (RELICS), and recently reported spectroscopic redshifts from the MUSE instrument on the Very Large Telescope (VLT). We measure an Einstein radius of ${\theta }_{E}\simeq 36^{\prime\prime} $ at z = 9 and a mass projected within 200 kpc of ${M}_{(200\mathrm{kpc})}={1.78}_{-0.03}^{+0.01}\times {10}^{14}$ M ${}_{\odot }$. Using this model, we measure a ratio between the mass attributed to cluster-member galaxy halos and the main cluster halo of order 1:100. We assess the probability to detect magnified high-redshift galaxies in the field of this cluster, both for comparison with RELICS HST results and as a prediction for the James Webb Space Telescope (JWST) Guaranteed Time Observations upcoming for this cluster. Our lensing analysis suggests that this cluster has similar lensing strength to other clusters in the RELICS program. Our lensing analysis predicts a detection of at least a few z ~ 6–8 galaxies behind this cluster, at odds with a recent analysis that yielded no such candidates in this field. Reliable strong lensing models are important for accurately predicting the intrinsic properties of lensed galaxies. As part of the RELICS program, our strong lensing model produced with the Lenstool parametric method is publicly available through the Mikulski Archive for Space Telescopes.

79 ASTRONOMY AND ASTROPHYSICS↗
NASA NTRS1991

NASA 1990 Multisensor Airborne Campaigns (MACs) for ecosystem and watershed studies

The Multisensor Airborne Campaign (MAC) focus within NASA's former Land Processes research program was conceived to achieve the following objectives: to acquire relatively complete, multisensor data sets for well-studied field sites, to add a strong remote sensing science component to ecology-, hydrology-, and geology-oriented field projects, to create a research environment that promotes strong interactions among scientists within the program, and to more efficiently utilize and compete for the NASA fleet of remote sensing aircraft. Four new MAC's were conducted in 1990: the Oregon Transect Ecosystem Research (OTTER) project along an east-west transect through central Oregon, the Forest Ecosystem Dynamics (FED) project at the Northern Experimental Forest in Howland, Maine, the MACHYDRO project in the Mahantango Creek watershed in central Pennsylvania, and the Walnut Gulch project near Tombstone, Arizona. The OTTER project is testing a model that estimates the major fluxes of carbon, nitrogen, and water through temperate coniferous forest ecosystems. The focus in the project is on short time-scale (days-year) variations in ecosystem function. The FED project is concerned with modeling vegetation changes of forest ecosystems using remotely sensed observations to extract biophysical properties of forest canopies. The focus in this project is on long time-scale (decades to millenia) changes in ecosystem structure. The MACHYDRO project is studying the role of soil moisture and its regulating effects on hydrologic processes. The focus of the study is to delineate soil moisture differences within a basin and their changes with respect to evapotranspiration, rainfall, and streamflow. The Walnut Gulch project is focused on the effects of soil moisture in the energy and water balance of arid and semiarid ecosystems and their feedbacks to the atmosphere via thermal forcing.

Wickland, Diane E.↗
NASA NTRS1992

MAC Europe 1991: Evaluation of AVIRIS, GER imaging spectrometry data for the land application testsite Oberpfaffenhofen

During the MAC Europe 91 Campaign, the area of Oberpfaffenhofen including the land application testsite Oberpfaffenhofen was flown by the AVIRIS imaging spectrometer, the GER 2 imaging spectrometer (63 band scanner), and two SAR systems (NASA/JPL AIRSAR and DLR E-SAR). In parallel to the overflights ground spectrometry (ASD, IRIS M IV) and atmospheric measurements were carried out in order to provide data for optical sensor calibration. Ground spectrometry measurements were carried out in the runway area of the DLR research center Oberpfaffenhofen. This area was used as well during the GER 2 European flight campaign EISAC 89 as a calibration target. The land application testsite Oberpfaffenhofen is located 3 km north of the DLR research center. During the MAC Europe 91 Campaign a ground survey was carried out for documentation in the ground information data base (vegetation type, vegetation geometry, soil type, and soil mixture). Crop stands analyzed were corn, barley and rape. The DLR runway area and the land application testsite Oberpfaffenhofen were flown with the AVIRIS on 29 July and with the GER 2 on 12 and 23 July and 3 Sep. AVIRIS and GER 2 scenes were processed and atmospherically corrected for optical data analysis of optical and radar data. For the AVIRIS and the GER 2 scenes, signal-to-noise ratios (SNR) estimates were calculated. An example of the reflectance of 6 calibration targets inside a GER 2 scene of Oberpfaffenhofen is given. SNR values for the GER 2 for a medium albedo target are given. The integrated analysis for the optical and radar data was carried out in cooperation with the DLR Institute for Microwave Technologies.

Lehmann, F.↗
NASA NTRS1993

Application of MAC-Europe AVIRIS data to the analysis of various alteration stages in the Landdmannalauger Hydrothermal Area (South Iceland)

In June 1991 extensive airborne remote sensing data-sets have been acquired over Iceland in the framework of the joint NASA/ESA Multisensor Airborne Campaign Europe (MAC-Europe). The study area is located within the Torfajokull central volcanic complex in South Iceland. This complex is composed by anomalously abundant rhyolitic acid volcanics, which underwent intensive hydrothermal alteration. Detailed studies of surface alteration of rhyolitic rocks in the area showed that all the major elements are leached as the rock is affected by complex mineralogical changes. Montmorillonite appears during the earliest stages of alteration. In the ultimate alteration product montmorillonite is absent and the rock consists mostly of amorphous silica, anatase, up to a volume of 50% kaolinite and variable amounts of native sulphur and pyrite. The case study presented shall endeavor to assess the potential of MAC-Europe AVIRIS and TMS data in determining a possible zonation of hydrothermal alteration in relationship to the active geo-thermal fields and structural features. To this end, the airborne data is analysed in comparison with laboratory spectral measurements of characteristics rock, soil, and vegetation samples collected in the study areaduring the summer of 1992. Various spectral mapping algorithms as well as unmixing approaches are tested and evaluated. Detailed geological and structural mapping as well as geochemical analysis of the main rock and soil types were performed to underpin the analysis of the airborne data.

Sommer, S.↗
NASA NTRS2014

Thrust Removal Scheme for the FAST-MAC Circulation Control Model Tested in the National Transonic Facility

A second wind tunnel test of the FAST-MAC circulation control semi-span model was recently completed in the National Transonic Facility at the NASA Langley Research Center. The model allowed independent control of four circulation control plenums producing a high momentum jet from a blowing slot near the wing trailing edge that was directed over a 15% chord simple-hinged flap. The model was configured for transonic testing of the cruise configuration with 0deg flap deflection to determine the potential for drag reduction with the circulation control blowing. Encouraging results from analysis of wing surface pressures suggested that the circulation control blowing was effective in reducing the transonic drag on the configuration, however this could not be quantified until the thrust generated by the blowing slot was correctly removed from the force and moment balance data. This paper will present the thrust removal methodology used for the FAST-MAC circulation control model and describe the experimental measurements and techniques used to develop the methodology. A discussion on the impact to the force and moment data as a result of removing the thrust from the blowing slot will also be presented for the cruise configuration, where at some Mach and Reynolds number conditions, the thrust-removed corrected data showed that a drag reduction was realized as a consequence of the blowing.

Chan, David T.↗
NASA NTRS2017

Transonic Drag Reduction Through Trailing-Edge Blowing on the FAST-MAC Circulation Control Model

A third wind tunnel test of the FAST-MAC circulation control semi-span model was completed in the National Transonic Facility at the NASA Langley Research Center where the model was configured for transonic testing of the cruise configuration with 0deg flap detection to determine the potential for transonic drag reduction with the circulation control blowing. The model allowed independent control of four circulation control plenums producing a high momentum jet from a blowing slot near the wing trailing edge that was directed over a 15% chord simple-hinged ap. Recent upgrades to transonic semi-span flow control testing at the NTF have demonstrated an improvement to overall data repeatability, particularly for the drag measurement, that allows for increased confidence in the data results. The static thrust generated by the blowing slot was removed from the wind-on data using force and moment balance data from wind-o thrust tares. This paper discusses the impact of the trailing-edge blowing to the transonic aerodynamics of the FAST-MAC model in the cruise configuration, where at flight Reynolds numbers, the thrust-removed corrected data showed that an overall drag reduction and increased aerodynamic efficiency was realized as a consequence of the blowing.

Chan, David T.↗
DOE OSTI2025

NSUF FY 2024 Annual Report: Microscopy and Characterization Suite (MaCS) and National Synchrotron Light Source-II (NSLS-II)

The Microscopy and Characterization Suite (MaCS) laboratory at the Center for Advanced Energy Studies (CAES) and the National Synchrotron Light Source-II (NSLS-II) at Brookhaven National Laboratory (BNL) partner with the Nuclear Science User Facilities (NSUF). This partnership provides funding that allows researchers to access these facilities at no cost for studying irradiation effects on nuclear fuels and materials. Through NSUF, both MaCS and NSLS-II support post-irradiation examination (PIE) and irradiation activities for NSUF Rapid Turnaround Experiments (RTE) and NSUF Consolidated Innovative Nuclear Research (CINR) awards. This report details the work completed at these facilities for NSUF competitively selected awards during fiscal year 2024.

99 GENERAL AND MISCELLANEOUS↗