SeaMicro Volume Server Power Reduction
Fact sheet about saving 75% of computing energy through an inter-connected array of low-power central processing units.
Data Center↗
SEARCH · Engineering Papers
Results for “ITP”
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.
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Yahoo! Compute Coop Next Generation Passive Cooling Design for Data Centers
Fact sheet about using outside air to cool data center equipment.
Data Center↗
Data Center Energy Practitioner (DCEP) Program
This document provides details about the U.S. Department of Energy Data Center Energy Practitioner (DCEP) Program.
Data Center↗
Nissan North America: How Sub-Metering Changed the Way a Plant Does Business
Case study - For Nissan, sub-metering data now drives decision-making and has empowered plant staff, helped senior leadership understand the bottom-line impact of proposed projects, and produced meaningful energy savings.
Case Study↗
Freescale Semiconductor Successfully Implements an Energy Management System
Through the Superior Energy Performance (SEP) plant certification program, Freescale Semiconductor implemented projects at the company's Oak Hill Fab plant that reduced annual energy consumption by 28 million kilowatt hours (kWh) of electricity and 26,000 million British thermal units (Btu) of natural gas between 2006 and 2009, saving more than $2 million each year. The plant is now certified at the SEP silver level, and has a management system in place to proactively manage the facility's energy resources in the future.
Case Study↗
MEDE 5-Zone Furnace System Checkout at NHL and EDL (Qualification)
This document contains instructions for the assembly and checkout of the Melt Evaporate Drain (MEDE) project 5-Zone Furnace system that is required for demonstration of sodium removal from a Fermi-1 reactor blanket element.
42 ENGINEERING↗
Dynamical Heating from Dark Compact Objects and Axion Minihalos: Implications for the 21-cm Signal
The temperature of baryons at the end of the cosmic dark ages can be inferred from observations of the 21-cm hyperfine transition in neutral hydrogen. Any energy injection from the dark sector can therefore be detected through these measurements. Dark compact objects and dark-matter substructures can modify the baryon temperature by transferring heat via dynamical friction. In this work, we evaluate the prospects for detecting dynamical friction-induced heating from dark compact objects with a mass in the range $10^2 M_{\odot}$ to $10^5 M_{\odot}$, as well as from axion minihalos, using upcoming 21-cm experiments. We find that both the 21-cm global signal and power-spectrum measurements will be sensitive to dark compact objects that constitute about 10% of the dark matter, and will substantially improve our sensitivity to axion-like particles with masses in the range $10^{-18}$ eV to $10^{-9}$ eV.
Bhalla, Badal [Oklahoma U.] (ORCID:000000030488664↗
First constraints on causal sources of primordial gravitational waves from BICEP/Keck, SPTpol, SPT-3G, Planck and WMAP $B$-mode data
Non-inflationary sources of gravitational waves in the early Universe generically predict causality-limited tensor power spectra at low frequencies. We report the first-ever constraints on such sources based on cosmic microwave background (CMB) $B$-mode polarization measurements. Using data from BICEP/Keck, SPTpol, SPT-3G, Planck, and WMAP, we constrain the amplitude of an early causal tensor (ECT) power spectrum parameterized by $r_{ect}$, the ratio of causal tensor power to total scalar power at $k~=~0.01$ Mpc$^{-1}$, and obtain a 95% CL upper limit of $r_{ect}<$ 0.0077. Since $r_{ect}$ can easily be related to the parameters of a given theory, our bound robustly constrains a broad class of well-motivated gravitational wave sources in the early universe, including first-order cosmological phase transitions, enhanced small-scale density perturbations, and various topological defects. Finally, we translate our limit into a bound on the present-day energy density in gravitational waves at ultra-low frequencies otherwise inaccessible to traditional gravitational wave detection strategies, including pulsar timing arrays, interferometers, and resonant cavities.
Zebrowski, Jessica A. [Fermilab; Chicago U., KICP]↗
Broadband multiwavelength properties of the archetypal blazar 3C 279 during the 2017 Event Horizon Telescope campaign
The archetypal blazar 3C 279 hosts a prominent relativistic jet and exhibits strong broadband variability across the electromagnetic spectrum. In April 2017, the Event Horizon Telescope (EHT) observed 3C 279, alongside one of the most extensive quasi-simultaneous multiwavelength (MWL) campaigns ever conducted. With the aim of investigating the physical processes governing 3C 279, we analyzed individual observations and multiband light curves, and constructed a new quasi-simultaneous MWL spectrum. We also performed phenomenological modeling using the turbulent extreme multi-zone (TEMZ) model to constrain the fundamental physical properties of the source. The EHT observations reveal a clear flux increase in the innermost core between April 5 and 11, 2017. Over a broader timescale, radio measurements at longer wavelengths show concurrent enhancements in core flux and polarization around mid-April, coinciding with the ejection of a superluminal knot. Record UV-optical flares with strong polarization variability occurred in late March, followed by gamma-ray activity that declined before the end of the EHT observing period. During this interval, the source remained in a low X-ray state and showed no detectable VHE emission. The TEMZ modeling suggests that the broadband spectrum and variability of 3C 279 can be explained within a jet scenario in which turbulent plasma cells are compressed by a stationary conical shock. However, alternative interpretations, such as magnetic reconnection or a moving shock-in-jet event, remain plausible. This coordinated MWL campaign advances our understanding of the origin of jet and gamma-ray emission in 3C 279, while also providing a comprehensive publicly available dataset that will serve as a valuable reference for future studies.
Principe, G. [Trieste U.; INFN, Trieste; Bologna, ↗