United States Department of Energy

About: United States Department of Energy is a government organization based out in Washington D.C., District of Columbia, United States. It is known for research contribution in the topics: Coal & Catalysis. The organization has 13656 authors who have published 14177 publications receiving 556962 citations. The organization is also known as: DOE & Department of Energy.

Closing the efficiency gap: barriers to the efficient use of energy

Abstract: Only half of the potential for improving U.S. energy efficiency over the next 20 years is likely to be achieved, given current government policies and programs. This large untapped potential to save money, improve environmental quality, and reduce the foreign trade deficit exists because of structural and market barriers that inhibit adoption of cost-effective energy-efficient practices and measures. Structural barriers include distortions in fuel prices, uncertainty about future fuel prices, limited access to capital, government fiscal and regulatory policies, codes and standards, and supply infrastructure limitations. Behavioral barriers include attitudes toward energy efficiency, perceived risk of energy-efficiency investments, information gaps, and misplaced incentives.

Thermodynamic and Transport Properties of Superconducting Mg 10 B 2

Abstract: Transport and thermodynamic properties of a sintered pellet of the newly discovered ${\mathrm{MgB}}_{2}$ superconductor have been measured to determine the characteristic critical magnetic fields and critical current densities. Both resistive transition and magnetization data give similar values of the upper critical field, ${H}_{c2}$, with magnetization data giving ${\mathrm{dH}}_{c2}/dT\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}0.44\mathrm{T}/\mathrm{K}$ at the transition temperature of ${T}_{c}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}40.2\mathrm{K}$. Close to the transition temperature, magnetization curves are thermodynamically reversible, but at low temperatures the trapped flux can be on the order of 1 T. The value of ${\mathrm{dH}}_{c}/\mathrm{dT}$ at ${T}_{c}$ is estimated to be about $12\mathrm{mT}/\mathrm{K}$, a value similar to classical superconductors like Sn. Hence, the Ginzburg-Landau parameter $\ensuremath{\kappa}\ensuremath{\sim}26$. Estimates of the critical supercurrent density, ${J}_{c}$, using hysteresis loops and the Bean model, give critical current densities on the order of ${10}^{5}\mathrm{A}/{\mathrm{cm}}^{2}$. Hence the supercurrent coupling through the grain boundaries is comparable to intermetallics like ${\mathrm{Nb}}_{3}\mathrm{Sn}$.

Gold-Adatom-Mediated Bonding in Self-Assembled Short-Chain Alkanethiolate Species on the Au(111) Surface

Abstract: Microscopic evidence for Au-adatom-induced self-assembly of alkanethiolate species on the Au(111) surface is presented. Based on STM measurements and density-functional theory calculations, a new model for the low-coverage self-assembled monolayer of alkanethiolate on the Au(111) surface is developed, which involves the adsorbate complexes incorporating Au adatoms. It is also concluded that the Au(111) herringbone reconstruction is lifted by the alkanethiolate self-assembly because the reconstructed surface layer provides reactive Au adatoms that drive self-assembly.

Chemically Bonded Phosphorus/Graphene Hybrid as a High Performance Anode for Sodium-Ion Batteries

Abstract: Room temperature sodium-ion batteries are of great interest for high-energy-density energy storage systems because of low-cost and natural abundance of sodium. Here, we report a novel phosphorus/graphene nanosheet hybrid as a high performance anode for sodium-ion batteries through facile ball milling of red phosphorus and graphene stacks. The graphene stacks are mechanically exfoliated to nanosheets that chemically bond with the surfaces of phosphorus particles. This chemical bonding can facilitate robust and intimate contact between phosphorus and graphene nanosheets, and the graphene at the particle surfaces can help maintain electrical contact and stabilize the solid electrolyte interphase upon the large volume change of phosphorus during cycling. As a result, the phosphorus/graphene nanosheet hybrid nanostructured anode delivers a high reversible capacity of 2077 mAh/g with excellent cycling stability (1700 mAh/g after 60 cycles) and high Coulombic efficiency (>98%). This simple synthesis approach and...

Environmental genomics reveals a single-species ecosystem deep within Earth.

Abstract: DNA from low-biodiversity fracture water collected at 2.8-kilometer depth in a South African gold mine was sequenced and assembled into a single, complete genome. This bacterium, Candidatus Desulforudis audaxviator, composes >99.9% of the microorganisms inhabiting the fluid phase of this particular fracture. Its genome indicates a motile, sporulating, sulfate-reducing, chemoautotrophic thermophile that can fix its own nitrogen and carbon by using machinery shared with archaea. Candidatus Desulforudis audaxviator is capable of an independent life-style well suited to long-term isolation from the photosphere deep within Earth's crust and offers an example of a natural ecosystem that appears to have its biological component entirely encoded within a single genome.