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.

Modular package for cooling a laser diode array

Abstract: A laser diode array is disclosed that includes a plurality of planar packages and active cooling. The laser diode array may be operated in a long duty cycle, or in continuous operation. A laser diode bar and a microchannel heat sink are thermally coupled in a compact, thin planar package having the laser diode bar located proximate to one edge. In an array, a number of such thin planar packages are secured together in a stacked configuration, in close proximity so that the laser diodes are spaced closely. The cooling means includes a microchannel heat sink that is attached proximate to the laser bar so that it absorbs heat generated by laser operation. To provide the coolant to the microchannels, each thin planar package comprises a thin inlet manifold and a thin outlet manifold connected to an inlet corridor and an outlet corridor. The inlet corridor comprises a hole extending through each of the packages in the array, and the outlet corridor comprises a hole extending through each of the packages in the array. The inlet and outlet corridors are connected to a conventional coolant circulation system. The laser diode array with active cooling has application as an optical pump for high power solid state lasers. Further, it can be incorporated in equipment such as communications devices and active sensors, and in military and space applications, and it can be useful in applications having space constraints and energy limitations.

Superconducting state magnetization and critical fields of single- crystal YNi2B2C

Abstract: Single crystals of YNi 2 B 2 C have been grown via high-temperature flux growth, using Ni 2 B as a solvent. Magnetization measurements have been carried out over a large portion of the magnetic field-temperature plane on a single crystal of YNi 2 B 2 C for field applied parallel to the c -axis in order to determine the range of thermodynamic reversibility and the critical magnetic fields. The magnetization is thermodynamically reversible within 2% of the magnetization for fields above 0.5 T and temperatures above 3 K. Near T c , the upper critical field has a slope of -0.32 T/K. The zero-temperature Ginzburg-Landau parameter κ is 13≈15, the penetration depth λ ab is about 150 nm, and the coherence distance λ ab is about 10 nm. The irreversibility line H irr ( T ) obeys H irr ( T ) = H irr (0) (1- T / T c ) 1.16 . The magnetization data below T c closely follow a logarithmic dependence on applied field, in the intermediate region, as predicted by the London model. The magnetization versus temperature curves shift uniformly to lower temperature as the field increases. Based on these measurements, YNi 2 B 2 C seems more similar to conventional low- T c superconductors than to high- T c superconductors.

Underground Mine Water for Heating and Cooling using Geothermal Heat Pump Systems

Abstract: In many regions of the world, flooded mines are a potentially cost-effective option for heating and cooling using geothermal heat pump systems. For example, a single coal seam in Pennsylvania, West Virginia, and Ohio contains 5.1 x 1012 L of water. The growing volume of water discharging from this one coal seam totals 380,000 L/min, which could theoretically heat and cool 20,000 homes. Using the water stored in the mines would conservatively extend this option to an order of magnitude more sites. Based on current energy prices, geothermal heat pump systems using mine water could reduce annual costs for heating by 67% and cooling by 50% over conventional methods (natural gas or heating oil and standard air conditioning).