Ku-band high efficiency GaAs MMIC power amplifiers

NASA Technical Reports Server (NTRS)

Tserng, H. Q.; Witkowski, L. C.; Wurtele, M.; Saunier, Paul

1988-01-01

The development of Ku-band high efficiency GaAs MMIC power amplifiers is examined. Three amplifier modules operating over the 13 to 15 GHz frequency range are to be developed. The first MMIC is a 1 W variable power amplifier (VPA) with 35 percent efficiency. On-chip digital gain control is to be provided. The second MMIC is a medium power amplifier (MPA) with an output power goal of 1 W and 40 percent power-added efficiency. The third MMIC is a high power amplifier (HPA) with 4 W output power goal and 40 percent power-added efficiency. An output power of 0.36 W/mm with 49 percent efficiency was obtained on an ion implanted single gate MESFET at 15 GHz. On a dual gate MESFET, an output power of 0.42 W/mm with 27 percent efficiency was obtained. A mask set was designed that includes single stage, two stage, and three stage single gate amplifiers. A single stage 600 micron amplifier produced 0.4 W/mm output power with 40 percent efficiency at 14 GHz. A four stage dual gate amplifier generated 500 mW of output power with 20 dB gain at 17 GHz. A four-bit digital-to-analog converter was designed and fabricated which has an output swing of -3 V to +/- 1 V.

EDITORIAL: Safety aspects of fusion power plants

NASA Astrophysics Data System (ADS)

Kolbasov, B. N.

2007-07-01

importance for the fusion power plant research programmes. The objective of this Technical Meeting was to examine in an integrated way all the safety aspects anticipated to be relevant to the first fusion power plant prototype expected to become operational by the middle of the century, leading to the first generation of economically viable fusion power plants with attractive S&E features. After screening by guest editors and consideration by referees, 13 (out of 28) papers were accepted for publication. They are devoted to the following safety topics: power plant safety; fusion specific operational safety approaches; test blanket modules; accident analysis; tritium safety and inventories; decommissioning and waste. The paper `Main safety issues at the transition from ITER to fusion power plants' by W. Gulden et al (EU) highlights the differences between ITER and future fusion power plants with magnetic confinement (off-site dose acceptance criteria, consequences of accidents inside and outside the design basis, occupational radiation exposure, and waste management, including recycling and/or final disposal in repositories) on the basis of the most recent European fusion power plant conceptual study. Ongoing S&E studies within the US inertial fusion energy (IFE) community are focusing on two design concepts. These are the high average power laser (HAPL) programme for development of a dry-wall, laser-driven IFE power plant, and the Z-pinch IFE programme for the production of an economically-attractive power plant using high-yield Z-pinch-driven targets. The main safety issues related to these programmes are reviewed in the paper `Status of IFE safety and environmental activities in the US' by S. Reyes et al (USA). The authors propose future directions of research in the IFE S&E area. In the paper `Recent accomplishments and future directions in the US Fusion Safety & Environmental Program' D. Petti et al (USA) state that the US fusion programme has long recognized that the S

Code TESLA for Modeling and Design of High-Power High-Efficiency Klystrons

DTIC Science & Technology

2011-03-01

CODE TESLA FOR MODELING AND DESIGN OF HIGH - POWER HIGH -EFFICIENCY KLYSTRONS * I.A. Chernyavskiy, SAIC, McLean, VA 22102, U.S.A. S.J. Cooke, B...and multiple-beam klystrons as high - power RF sources. These sources are widely used or proposed to be used in accelerators in the future. Comparison...of TESLA modelling results with experimental data for a few multiple-beam klystrons are shown. INTRODUCTION High - power and high -efficiency

High-Gain High-Field Fusion Plasma

PubMed Central

Li, Ge

2015-01-01

A Faraday wheel (FW)—an electric generator of constant electrical polarity that produces huge currents—could be implemented in an existing tokamak to study high-gain high-field (HGHF) fusion plasma, such as the Experimental Advanced Superconducting Tokamak (EAST). HGHF plasma can be realized in EAST by updating its pulsed-power system to compress plasma in two steps by induction fields; high gains of the Lawson trinity parameter and fusion power are both predicted by formulating the HGHF plasma. Both gain rates are faster than the decrease rate of the plasma volume. The formulation is checked by earlier ATC tests. Good agreement between theory and tests indicates that scaling to over 10 T at EAST may be possible by two-step compressions with a compression ratio of the minor radius of up to 3. These results point to a quick new path of fusion plasma study, i.e., simulating the Sun by EAST. PMID:26507314

High-Efficiency Hall Thruster Discharge Power Converter

NASA Technical Reports Server (NTRS)

Jaquish, Thomas

2015-01-01

Busek Company, Inc., is designing, building, and testing a new printed circuit board converter. The new converter consists of two series or parallel boards (slices) intended to power a high-voltage Hall accelerator (HiVHAC) thruster or other similarly sized electric propulsion devices. The converter accepts 80- to 160-V input and generates 200- to 700-V isolated output while delivering continually adjustable 300-W to 3.5-kW power. Busek built and demonstrated one board that achieved nearly 94 percent efficiency the first time it was turned on, with projected efficiency exceeding 97 percent following timing software optimization. The board has a projected specific mass of 1.2 kg/kW, achieved through high-frequency switching. In Phase II, Busek optimized to exceed 97 percent efficiency and built a second prototype in a form factor more appropriate for flight. This converter then was integrated with a set of upgraded existing boards for powering magnets and the cathode. The program culminated with integrating the entire power processing unit and testing it on a Busek thruster and on NASA's HiVHAC thruster.

Status and future prospects of laser fusion and high power laser applications

NASA Astrophysics Data System (ADS)

Mima, Kunioki

2010-08-01

In Asia, there are many institutes for the R&D of high power laser science and applications. They are 5 major institutes in Japan, 4 major institutes in China, 2 institutes in Korea, and 3 institutes in India. The recent achievements and future prospects of those institutes will be over viewed. In the laser fusion research, the FIREX-I project in Japan has been progressing. The 10kJ short pulse LFEX laser has completed and started the experiments with a single beam. About 1kJ pulse energy will be injected into a cone target. The experimental results of the FIREX experiments will be presented. As the target design for the experiments, a new target, namely, a double cone target was proposed, in which the high energy electrons are well confined and the heating efficiency is significantly improved. Together with the fusion experiments, Osaka University has carried out laboratory astrophysics experiments on photo ionizing plasmas to observe a unique X-ray spectrum from non-LTE plasmas. In 2008, Osaka university has started a new Photon research center in relation with the new program: Consortium for Photon Science and Technology: C-PhoST, in which ultra intense laser plasmas research and related education will be carried out for 10 years. At APRI, JAEA, the fundamental science on the relativistic laser plasmas and the applications of laser particle acceleration has been developed. The application of laser ion acceleration has been investigated on the beam cancer therapy since 2007. In China, The high power glass laser: Shenguan-II and a peta watt beam have been operated to work on radiation hydro dynamics at SIOFM Shanghai. The laser material and optics are developed at SIOFM and LFRC. The IAPCM and the IOP continued the studies on radiation hydrodynamics and on relativistic laser plasmas interactions. At LFRC in China, the construction of Shenguan III glass laser of 200kJ in blue has progressed and will be completed in 2012. Together with the Korean program, I will

Energy analysis of coal, fission, and fusion power plants

NASA Astrophysics Data System (ADS)

Tsoulfanidis, N.

1981-04-01

The method of net energy analysis has been applied to coal, fission, and fusion power plants. Energy consumption over the lifetime of the plants has been calculated for construction, operation and maintenance, fuel, public welfare, and land use and restoration. Thermal and electric energy requirements were obtained separately for each energy consuming sector. The results of the study are presented in three ways: total energy requirements, energy gain ratio, and payback periods. All three types of power plants are net producers of energy. The coal and fusion power plants are superior to fission plants from the energy efficiency point of view. Fission plants will improve considerably if the centrifuge replaces the gaseous diffusion as a method of enrichment.

The Physics of Advanced High-Gain Targets for Inertial Fusion Energy

NASA Astrophysics Data System (ADS)

Perkins, L. John

2010-11-01

In ca. 2011-2012, the National Ignition Facility is poised to demonstrate fusion ignition and gain in the laboratory for the first time. This key milestone in the development of inertial confinement fusion (ICF) can be expected to engender interest in the development of inertial fusion energy (IFE) and expanded efforts on a number of advanced targets that may achieve high fusion energy gain at lower driver energies. In this tutorial talk, we will discuss the physics underlying ICF ignition and thermonuclear burn, examine the requirements for high gain, and outline candidate R&D programs that will be required to assess the performance of these target concepts under various driver systems including lasers, heavy-ions and pulsed power. Such target concepts include those operating by fast ignition, shock ignition, impact ignition, dual-density, magnetically-insulated, one- and two-sided drive, etc., some of which may have potential to burn advanced, non-DT fusion fuels. We will then delineate the role of such targets in their application to the production of high average fusion power. Here, systems studies of IFE economics suggest that we should strive for target fusion gains of around 100 at drive energies of 1MJ, together with corresponding rep-rates of up to 10Hz and driver electrical efficiencies around 15%. In future years, there may be exciting opportunities to study such ``innovative confinement concepts'' with prospects of fielding them on facilities such as NIF to obtain high fusion energy gains on a single shot basis.

Fusion power: a challenge for materials science.

PubMed

Duffy, D M

2010-07-28

The selection and design of materials that will withstand the extreme conditions of a fusion power plant has been described as one of the greatest materials science challenges in history. The high particle flux, high thermal load, thermal mechanical stress and the production of transmutation elements combine to produce a uniquely hostile environment. In this paper, the materials favoured for the diverse roles in a fusion power plant are discussed, along with the experimental and modelling techniques that are used to advance the understanding of radiation damage in materials. Areas where further research is necessary are highlighted.

High-Energy Space Propulsion Based on Magnetized Target Fusion

NASA Technical Reports Server (NTRS)

Thio, Y. C. F.; Freeze, B.; Kirkpatrick, R. C.; Landrum, B.; Gerrish, H.; Schmidt, G. R.

1999-01-01

A conceptual study is made to explore the feasibility of applying magnetized target fusion (MTF) to space propulsion for omniplanetary travel. Plasma-jet driven MTF not only is highly amenable to space propulsion, but also has a number of very attractive features for this application: 1) The pulsed fusion scheme provides in situ a very dense hydrogenous liner capable of moderating the neutrons, converting more than 97% of the neutron energy into charged particle energy of the fusion plasma available for propulsion. 2) The fusion yield per pulse can be maintained at an attractively low level (< 1 GJ) despite a respectable gain in excess of 70. A compact, low-weight engine is the result. An engine with a jet power of 25 GW, a thrust of 66 kN, and a specific impulse of 77,000 s, can be achieved with an overall engine mass of about 41 metric tons, with a specific power density of 605 kW/kg, and a specific thrust density of 1.6 N/kg. The engine is rep-rated at 40 Hz to provide this power and thrust level. At a practical rep-rate limit of 200 Hz, the engine can deliver 128 GW jet power and 340 kN of thrust, at specific power and thrust density of 1,141 kW/kg and 3 N/kg respectively. 3) It is possible to operate the magnetic nozzle as a magnetic flux compression generator in this scheme, while attaining a high nozzle efficiency of 80% in converting the spherically radial momentum of the fusion plasma to an axial impulse. 4) A small fraction of the electrical energy generated from the flux compression is used directly to recharge the capacitor bank and other energy storage equipment, without the use of a highvoltage DC power supply. A separate electrical generator is not necessary. 5) Due to the simplicity of the electrical circuit and the components, involving mainly inductors, capacitors, and plasma guns, which are connected directly to each other without any intermediate equipment, a high rep-rate (with a maximum of 200 Hz) appears practicable. 6) All fusion related

New High Gain Target Design for a Laser Fusion Power Plant

DTIC Science & Technology

2000-06-07

target with a minimum energy gain, about 100. Demonstration of ignition or low gain is only important for fusion energy if it leads into a target concept...nonlinear saturation of these instabilities. Our approach is to try to avoid them. 4. A Development Path to Fusion Energy The laser and target concept...on the exact date required to develop fusion energy , it would be worthwhile for a power plant development program to provide enough time and funds

High efficiency solar photovoltaic power module concept

NASA Technical Reports Server (NTRS)

Bekey, I.

1978-01-01

The investigation of a preliminary concept for high efficiency solar power generation in space is presented. The concept was a synergistic combination of spectral splitting, tailored bandgap cells, high concentration ratios, and cool cell areas.

High Power High Efficiency Diode Laser Stack for Processing

NASA Astrophysics Data System (ADS)

Gu, Yuanyuan; Lu, Hui; Fu, Yueming; Cui, Yan

2018-03-01

High-power diode lasers based on GaAs semiconductor bars are well established as reliable and highly efficient laser sources. As diode laser is simple in structure, small size, longer life expectancy with the advantages of low prices, it is widely used in the industry processing, such as heat treating, welding, hardening, cladding and so on. Respectively, diode laser could make it possible to establish the practical application because of rectangular beam patterns which are suitable to make fine bead with less power. At this power level, it can have many important applications, such as surgery, welding of polymers, soldering, coatings and surface treatment of metals. But there are some applications, which require much higher power and brightness, e.g. hardening, key hole welding, cutting and metal welding. In addition, High power diode lasers in the military field also have important applications. So all developed countries have attached great importance to high-power diode laser system and its applications. This is mainly due their low performance. In this paper we will introduce the structure and the principle of the high power diode stack.

Fusion Power.

ERIC Educational Resources Information Center

Dingee, David A.

1979-01-01

Discusses the extraordinary potential, the technical difficulties, and the financial problems that are associated with research and development of fusion power plants as a major source of energy. (GA)

High Efficiency Microwave Power Amplifier: From the Lab to Industry

NASA Technical Reports Server (NTRS)

Sims, William Herbert, III; Bell, Joseph L. (Technical Monitor)

2001-01-01

Since the beginnings of space travel, various microwave power amplifier designs have been employed. These included Class-A, -B, and -C bias arrangements. However, shared limitation of these topologies is the inherent high total consumption of input power associated with the generation of radio frequency (RF)/microwave power. The power amplifier has always been the largest drain for the limited available power on the spacecraft. Typically, the conversion efficiency of a microwave power amplifier is 10 to 20%. For a typical microwave power amplifier of 20 watts, input DC power of at least 100 watts is required. Such a large demand for input power suggests that a better method of RF/microwave power generation is required. The price paid for using a linear amplifier where high linearity is unnecessary includes higher initial and operating costs, lower DC-to-RF conversion efficiency, high power consumption, higher power dissipation and the accompanying need for higher capacity heat removal means, and an amplifier that is more prone to parasitic oscillation. The first use of a higher efficiency mode of power generation was described by Baxandall in 1959. This higher efficiency mode, Class-D, is achieved through distinct switching techniques to reduce the power losses associated with switching, conduction, and gate drive losses of a given transistor.

High-Efficiency Microwave Power Amplifier

NASA Technical Reports Server (NTRS)

Sims, Williams H.

2005-01-01

A high-efficiency power amplifier that operates in the S band (frequencies of the order of a few gigahertz) utilizes transistors operating under class-D bias and excitation conditions. Class-D operation has been utilized at lower frequencies, but, until now, has not been exploited in the S band. Nominally, in class D operation, a transistor is switched rapidly between "on" and "off" states so that at any given instant, it sustains either high current or high voltage, but not both at the same time. In the ideal case of zero "on" resistance, infinite "off" resistance, zero inductance and capacitance, and perfect switching, the output signal would be a perfect square wave. Relative to the traditional classes A, B, and C of amplifier operation, class D offers the potential to achieve greater power efficiency. In addition, relative to class-A amplifiers, class-D amplifiers are less likely to go into oscillation. In order to design this amplifier, it was necessary to derive mathematical models of microwave power transistors for incorporation into a larger mathematical model for computational simulation of the operation of a class-D microwave amplifier. The design incorporates state-of-the-art switching techniques applicable only in the microwave frequency range. Another major novel feature is a transmission-line power splitter/combiner designed with the help of phasing techniques to enable an approximation of a square-wave signal (which is inherently a wideband signal) to propagate through what would, if designed in a more traditional manner, behave as a more severely band-limited device (see figure). The amplifier includes an input, a driver, and a final stage. Each stage contains a pair of GaAs-based field-effect transistors biased in class D. The input signal can range from -10 to +10 dBm into a 50-ohm load. The table summarizes the performances of the three stages

808nm high-power high-efficiency GaAsP/GaInP laser bars

NASA Astrophysics Data System (ADS)

Wang, Ye; Yang, Ye; Qin, Li; Wang, Chao; Yao, Di; Liu, Yun; Wang, Lijun

2008-11-01

808nm high power diode lasers, which is rapidly maturing technology technically and commercially since the introduction in 1999 of complete kilowatt-scale diode laser systems, have important applications in the fields of industry and pumping solid-state lasers (DPSSL). High power and high power conversion efficiency are extremely important in diode lasers, and they could lead to new applications where space, weight and electrical power are critical. High efficiency devices generate less waste heat, which means less strain on the cooling system and more tolerance to thermal conductivity variation, a lower junction temperature and longer lifetimes. Diode lasers with Al-free materials have superior power conversion efficiency compared with conventional AlGaAs/GaAs devices because of their lower differential series resistance and higher thermal conductivity. 808nm GaAsP/GaInP broad-waveguide emitting diode laser bars with 1mm cavity length have been fabricated. The peak power can reach to 100.9W at 106.5A at quasicontinuous wave operation (200μs, 1000Hz). The maximum power conversion efficiency is 57.38%. Based on these high power laser bars, we fabricate a 1x3 arrays, the maximum power is 64.3W in continuous wave mode when the current is 25.0A. And the threshold current is 5.9A, the slope efficiency is 3.37 W/A.

A new simpler way to obtain high fusion power gain in tandem mirrors

NASA Astrophysics Data System (ADS)

Fowler, T. K.; Moir, R. W.; Simonen, T. C.

2017-05-01

From the earliest days of fusion research, Richard F. Post and other advocates of magnetic mirror confinement recognized that mirrors favor high ion temperatures where nuclear reaction rates < σ v> begin to peak for all fusion fuels. In this paper we review why high ion temperatures are favored, using Post’s axisymmetric Kinetically Stabilized Tandem Mirror as the example; and we offer a new idea that appears to greatly improve reactor prospects at high ion temperatures. The idea is, first, to take advantage of recent advances in superconducting magnet technology to minimize the size and cost of End Plugs; and secondly, to utilize parallel advances in gyrotrons that would enable intense electron cyclotron heating (ECH) in these high field End Plugs. The yin-yang magnets and thermal barriers that complicated earlier tandem mirror designs are not required. We find that, concerning end losses, intense ECH in symmetric End Plugs could increase the fusion power gain Q, for both DT and Catalyzed DD fuel cycles, to levels competitive with steady-state tokamaks burning DT fuel. Radial losses remain an issue that will ultimately determine reactor viability.

Thermionic/AMTEC cascade converter concept for high-efficiency space power

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hagan, T.H. van; Smith, J.N. Jr.; Schuller, M.

1996-12-31

This paper presents trade studies that address the use of the thermionic/AMTEC cell--a cascaded, high-efficiency, static power conversion concept that appears well-suited to space power applications. Both the thermionic and AMTEC power conversion approaches have been shown to be promising candidates for space power. Thermionics offers system compactness via modest efficiency at high heat rejection temperatures, and AMTEC offers high efficiency at modest heat rejection temperature. From a thermal viewpoint the two are ideally suited for cascaded power conversion: thermionic heat rejection and AMTEC heat source temperatures are essentially the same. In addition to realizing conversion efficiencies potentially as highmore » as 35--40%, such a cascade offers the following perceived benefits: survivability; simplicity; technology readiness; and technology growth. Mechanical approaches and thermal/electric matching criteria for integrating thermionics and AMTEC into a single conversion device are described. Focusing primarily on solar thermal space power applications, parametric trends are presented to show the performance and cost potential that should be achievable with present-day technology in cascaded thermionic/AMTEC systems.« less

Ka-Band TWT High-Efficiency Power Combiner for High-Rate Data Transmission

NASA Technical Reports Server (NTRS)

Wintucky, Edwin G.; Simons, Rainee; Vaden, Karl R.; Lesny, Gary G.; Glass, Jeffrey L.

2007-01-01

A four-port magic-T hybrid waveguide junction serves as the central component of a high-efficiency two-way power combiner circuit for transmitting a high-rate phase-modulated digital signal at a carrier frequency in the Ka-band (between 27 and 40 GHz). This power combiner was developed to satisfy a specific requirement to efficiently combine the coherent outputs of two traveling-wavetube (TWT) amplifiers that are typically characterized by power levels on the order of 100 W or more. In this application, the use of a waveguide-based power combiner (instead of a coaxial-cable- or microstrip-based power combiner, for example) is dictated by requirements for low loss, high power-handling capability, and broadband response. Combiner efficiencies were typically 90 percent or more over both the linear and saturated output power regions of operation of the TWTs . Figure 1 depicts the basic configuration of the magic-T hybrid junction. The coherent outputs of the two TWTs enter through ports 1 and 4. As a result of the orientations of the electromagnetic fields, which also provides a needed high port-to-port isolation, of these two input signals and the interior design of the magic-T junction, the input powers are divided so as to add in phase at one output port (port 2), and to be opposite in phase and hence cancel each other at the opposite coplanar output port (port 3). The net result is that the output power at port 2 is essentially double that of the output of one TWT, minus the power lost in the magic-T hybrid junction. Optimum performance as a high-efficiency power combiner thus requires a balance of both power and phase at the input ports of the magic-T. Replicas of this two-way combiner can be arranged in a binary configuration to obtain a 2n-way (where n is an integer) combiner. For example, Figure 2 illustrates the use of three two-way combiners to combine the outputs of four TWTs.

Fusion power for space propulsion.

NASA Technical Reports Server (NTRS)

Roth, R.; Rayle, W.; Reinmann, J.

1972-01-01

Principles of operation, interplanetary orbit-to-orbit mission capabilities, technical problems, and environmental safeguards are examined for thermonuclear fusion propulsion systems. Two systems examined include (1) a fusion-electric concept in which kinetic energy of charged particles from the plasma is converted into electric power (for accelerating the propellant in an electrostatic thrustor) by the van de Graaf generator principle and (2) the direct fusion rocket in which energetic plasma lost from the reactor has a suitable amount of added propellant to obtain the optimum exhaust velocity. The deuterium-tritium and the deuterium/helium-3 reactions are considered as suitable candidates, and attention is given to problems of cryogenic refrigeration systems, magnet shielding, and high-energy particle extraction and guidance.

An accelerated fusion power development plan

NASA Astrophysics Data System (ADS)

Dean, Stephen O.; Baker, Charles C.; Cohn, Daniel R.; Kinkead, Susan D.

1991-06-01

Energy for electricity and transportation is a national issue with worldwide environmental and political implications. The world must have energy options for the next century that are not vulnerable to possible disruption for technical, environmental, public confidence, or other reasons. Growing concerns about the greenhouse effect and the safety of transporting oil may lead to reduced burning of coal and other fossil fuels, and the incidents at Three Mile Island and Chernobyl, as well as nuclear waste storage problems, have eroded public acceptance of nuclear fission. Meeting future world energy needs will require improvements in energy efficiency and conservation. However, the world will soon need new central station power plants and increasing amounts of fuel for the transportation sector. The use of fossil fuels, and possibly even fission power, will very likely be restricted because of environmental, safety, and, eventually, supply considerations. Time is running out for policymakers. New energy technologies cannot be brought to the marketplace overnight. Decades are required to bring a new energy production technology from conception to full market penetration. With the added urgency to mitigate deleterious environmental effects of energy use, policymakers must act decisively now to establish and support vigorous energy technology development programs. The U.S. has invested 8 billion over the past 40 years in fusion research and development. If the U.S. fusion program proceeds according to its present strategy, an additional 40 years, and more money, will be expended before fusion will provide commercial electricity. Such an extended schedule is neither cost-effective nor technically necessary. It is time to launch a national venture to construct and operate a fusion power pilot plant. Such a plant could be operational within 15 years of a national commitment to proceed.

A low-power, high-efficiency Ka-band TWTA

NASA Technical Reports Server (NTRS)

Curren, A. N.; Dayton, J. A., Jr.; Palmer, R. W.; Force, D. A.; Tamashiro, R. N.; Wilson, J. F.; Dombro, L.; Harvey, W. L.

1991-01-01

A NASA-sponsored program is described for developing a high-efficiency low-power TWTA operating at 32 GHz and meeting the requirements for the Cassini Mission to study Saturn. The required RF output power of the helix TWT is 10 watts, while the dc power from the spacecraft is limited to about 30 watts. The performance level permits the transmission to earth of all mission data. Several novel technologies are incorporated into the TWT to achieve this efficiency including an advanced dynamic velocity taper characterized by a nonlinear reduction in pitch in the output helix section and a multistage depressed collector employing copper electrodes treated for secondary electron-emission suppression. Preliminary program results are encouraging: RF output power of 10.6 watts is obtained at 14-mA beam current and 5.2-kV helix voltage with overall TWT efficiency exceeding 40 percent.

A low-power, high-efficiency Ka-band TWTA

NASA Astrophysics Data System (ADS)

Curren, A. N.; Dayton, J. A., Jr.; Palmer, R. W.; Force, D. A.; Tamashiro, R. N.; Wilson, J. F.; Dombro, L.; Harvey, W. L.

1991-11-01

A NASA-sponsored program is described for developing a high-efficiency low-power TWTA operating at 32 GHz and meeting the requirements for the Cassini Mission to study Saturn. The required RF output power of the helix TWT is 10 watts, while the dc power from the spacecraft is limited to about 30 watts. The performance level permits the transmission to earth of all mission data. Several novel technologies are incorporated into the TWT to achieve this efficiency including an advanced dynamic velocity taper characterized by a nonlinear reduction in pitch in the output helix section and a multistage depressed collector employing copper electrodes treated for secondary electron-emission suppression. Preliminary program results are encouraging: RF output power of 10.6 watts is obtained at 14-mA beam current and 5.2-kV helix voltage with overall TWT efficiency exceeding 40 percent.

High Power High Efficiency Ka-Band Power Combiners for Solid-State Devices

NASA Technical Reports Server (NTRS)

Freeman, Jon C.; Wintucky, Edwin G.; Chevalier, Christine T.

2006-01-01

Wide-band power combining units for Ka-band are simulated for use as MMIC amplifier applications. Short-slot couplers as well as magic-tees are the basic elements for the combiners. Wide bandwidth (5 GHz) and low insertion (approx.0.2 dB) and high combining efficiencies (approx.90 percent) are obtained.

Overview on the high power excimer laser technology

NASA Astrophysics Data System (ADS)

Liu, Jingru

2013-05-01

High power excimer laser has essential applications in the fields of high energy density physics, inertial fusion energy and industry owing to its advantages such as short wavelength, high gain, wide bandwidth, energy scalable and repetition operating ability. This overview is aimed at an introduction and evaluation of enormous endeavor of the international high power excimer laser community in the last 30 years. The main technologies of high power excimer laser are reviewed, which include the pumping source technology, angular multiplexing and pulse compressing, beam-smoothing and homogenous irradiation, high efficiency and repetitive operation et al. A high power XeCl laser system developed in NINT of China is described in detail.

AMTEC: High efficiency static conversion for space power

NASA Technical Reports Server (NTRS)

Bankston, C. P.; Shirbacheh, M.

1986-01-01

Future manned and unmanned space missions will require reliable, high efficiency energy conversion systems. For a manned Mars mission, power levels in the range of 10 to 100 kWe will be needed. The Alkali Metal Thermoelectric Converter (AMTEC) is a direct energy conversion technology with the potential to meet these needs. The AMTEC is a thermally regenerative electrochemical device that derives its operation from the sodium ion conducting properties of beta-alumina solid electrolyte (BASE). To date, an efficiency of 19%, area power density of 1 W/sq cm, and a lifetime of 10,000 hours at high temperature were demonstrated in laboratory devices. Systems studies show that projected AMTEC systems equal or surpass the performance of other static or dynamic systems in applications of 1 kWe-1 MWe. Thus, the laboratory experiments and applications studies conducted to date have shown that the AMTEC posseses great potential. In order to bring this technology to the stage where prototype units can be built and operated, several technical issues must be addressed. These include the need for long life, high power electrodes, minimization of radiative parasitic losses, and high temperature seals. In summary, the evidence shows that if AMTEC is developed, it can play a significant role in future space power applications.

High Efficiency Ka-Band Solid State Power Amplifier Waveguide Power Combiner

NASA Technical Reports Server (NTRS)

Wintucky, Edwin G.; Simons, Rainee N.; Chevalier, Christine T.; Freeman, Jon C.

2010-01-01

A novel Ka-band high efficiency asymmetric waveguide four-port combiner for coherent combining of two Monolithic Microwave Integrated Circuit (MMIC) Solid State Power Amplifiers (SSPAs) having unequal outputs has been successfully designed, fabricated and characterized over the NASA deep space frequency band from 31.8 to 32.3 GHz. The measured combiner efficiency is greater than 90 percent, the return loss greater than 18 dB and input port isolation greater than 22 dB. The manufactured combiner was designed for an input power ratio of 2:1 but can be custom designed for any arbitrary power ratio. Applications considered are NASA s space communications systems needing 6 to 10 W of radio frequency (RF) power. This Technical Memorandum (TM) is an expanded version of the article recently published in Institute of Engineering and Technology (IET) Electronics Letters.

Propulsion and Power Generation Capabilities of a Dense Plasma Focus (DPF) Fusion System for Future Military Aerospace Vehicles

NASA Astrophysics Data System (ADS)

Knecht, Sean D.; Thomas, Robert E.; Mead, Franklin B.; Miley, George H.; Froning, David

2006-01-01

The objective of this study was to perform a parametric evaluation of the performance and interface characteristics of a dense plasma focus (DPF) fusion system in support of a USAF advanced military aerospace vehicle concept study. This vehicle is an aerospace plane that combines clean ``aneutronic'' dense plasma focus (DPF) fusion power and propulsion technology, with advanced ``lifting body''-like airframe configurations utilizing air-breathing MHD propulsion and power technology within a reusable single-stage-to-orbit (SSTO) vehicle. The applied approach was to evaluate the fusion system details (geometry, power, T/W, system mass, etc.) of a baseline p-11B DPF propulsion device with Q = 3.0 and thruster efficiency, ɛprop = 90% for a range of thrust, Isp and capacitor specific energy values. The baseline details were then kept constant and the values of Q and ɛprop were varied to evaluate excess power generation for communication systems, pulsed-train plasmoid weapons, ultrahigh-power lasers, and gravity devices. Thrust values were varied between 100 kN and 1,000 kN with Isp of 1,500 s and 2,000 s, while capacitor specific energy was varied from 1 - 15 kJ/kg. Q was varied from 3.0 to 6.0, resulting in gigawatts of excess power. Thruster efficiency was varied from 0.9 to 1.0, resulting in hundreds of megawatts of excess power. Resulting system masses were on the order of 10's to 100's of metric tons with thrust-to-weight ratios ranging from 2.1 to 44.1, depending on capacitor specific energy. Such a high thrust/high Isp system with a high power generation capability would allow military versatility in sub-orbital space, as early as 2025, and beyond as early as 2050. This paper presents the results that coincide with a total system mass between 15 and 20 metric tons.

High efficiency GaP power conversion for Betavoltaic applications

NASA Astrophysics Data System (ADS)

Sims, Paul E.; Dinetta, Louis C.; Barnett, Allen M.

1994-09-01

AstroPower is developing a gallium phosphide (GaP) based energy converter optimized for radio luminescent light-based power supplies. A 'two-step' or 'indirect' process is used where a phosphor is excited by radioactive decay products to produce light that is then converted to electricity by a photovoltaic energy converter. This indirect conversion of beta-radiation to electrical energy can be realized by applying recent developments in tritium based radio luminescent (RL) light sources in combination with the high conversion efficiencies that can be achieved under low illumination with low leakage, gallium phosphide based devices. This tritium to light approach is inherently safer than battery designs that incorporate high activity radionuclides because the beta particles emitted by tritium are of low average energy and are easily stopped by a thin layer of glass. GaP layers were grown by liquid phase epitaxy and p/n junction devices were fabricated and characterized for low light intensity power conversion. AstroPower has demonstrated the feasibility of the GaP based energy converter with the following key results: 23.54 percent conversion efficiency under 968 muW/sq cm 440 nm blue light, 14.59 percent conversion efficiency for 2.85 muW/sq cm 440 nm blue light, and fabrication of working 5 V array. We have also determined that at least 20 muW/sq cm optical power is available for betavoltaic power systems. Successful developments of this device is an enabling technology for low volume, safe, high voltage, milliwatt power supplies with service lifetimes in excess of 12 years.

High efficiency GaP power conversion for Betavoltaic applications

NASA Technical Reports Server (NTRS)

Sims, Paul E.; Dinetta, Louis C.; Barnett, Allen M.

1994-01-01

AstroPower is developing a gallium phosphide (GaP) based energy converter optimized for radio luminescent light-based power supplies. A 'two-step' or 'indirect' process is used where a phosphor is excited by radioactive decay products to produce light that is then converted to electricity by a photovoltaic energy converter. This indirect conversion of beta-radiation to electrical energy can be realized by applying recent developments in tritium based radio luminescent (RL) light sources in combination with the high conversion efficiencies that can be achieved under low illumination with low leakage, gallium phosphide based devices. This tritium to light approach is inherently safer than battery designs that incorporate high activity radionuclides because the beta particles emitted by tritium are of low average energy and are easily stopped by a thin layer of glass. GaP layers were grown by liquid phase epitaxy and p/n junction devices were fabricated and characterized for low light intensity power conversion. AstroPower has demonstrated the feasibility of the GaP based energy converter with the following key results: 23.54 percent conversion efficiency under 968 muW/sq cm 440 nm blue light, 14.59 percent conversion efficiency for 2.85 muW/sq cm 440 nm blue light, and fabrication of working 5 V array. We have also determined that at least 20 muW/sq cm optical power is available for betavoltaic power systems. Successful developments of this device is an enabling technology for low volume, safe, high voltage, milliwatt power supplies with service lifetimes in excess of 12 years.

A low-power, high-efficiency Ka-band TWTA

NASA Astrophysics Data System (ADS)

Curren, Arthur N.; Dayton, James A., Jr.; Palmer, Raymond W.; Force, Dale A.; Tamashiro, Rodney N.; Wilson, John F.; Dombro, Louis; Harvey, Wayne L.

1992-03-01

NASA has developed a new class of Ka-band TWT amplifiers (TWTAs) which achieve their high efficiency/low power performance goals by means of an advanced dynamic velocity taper (DVT). The DVT is characterized by a continuous, nonlinear reduction in helix pitch from its initial synchronous value in the output section of the TWT to near the end of the helix. Another efficiency-maximizing feature is the inclusion of a multistage depressed collector employing oxygen-free, high-conductivity Cu electrodes treated for secondary electron emission suppression by means of ion bombardment. An efficiency of 43 percent is expected to be reached.

High Efficiency Power Combining of Ka-Band TWTs for High Data Rate Communications

NASA Technical Reports Server (NTRS)

Wintucky, E. G.; Simons, R. N.; Vaden, K. R.; Lesny, G. G.; Glass, J. L.

2006-01-01

Future NASA deep space exploration missions are expected in some cases to require telecommunication systems capable of operating at very high data rates (potentially 1 Gbps or more) for the transmission back to Earth of large volumes of scientific data, which means high frequency transmitters with large bandwidth. Among the Ka band frequencies of interest are the present 500 MHz Deep Space Network (DSN) band of 31.8 to 32.3 GHz and a broader band at 37-38 GHz allocated for space science [1]. The large distances and use of practical antenna sizes dictate the need for high transmitter power of up to 1 kW or more. High electrical efficiency is also a requirement. The approach investigated by NASA GRC is a novel wave guide power combiner architecture based on a hybrid magic-T junction for combining the power output from multiple TWTs [1,2]. This architecture was successfully demonstrated and is capable of both high efficiency (90-95%, depending on frequency) and high data rate transmission (up to 622 Mbps) in a two-way power combiner circuit for two different pairs of Ka band TWTs at two different frequency bands. One pair of TWTs, tested over a frequency range of 29.1 to 29.6 GHz, consisted of two 110-115W TWTs previously used in uplink data transmission evaluation terminals in the NASA Advanced Communications Technology Satellite (ACTS) program [1,2]. The second pair was two 100W TWTs (Boeing 999H) designed for high efficiency operation (greater than 55%) over the DSN frequency band of 31.8 to 32.3 GHz [3]. The presentation will provide a qualitative description of the wave guide circuit, results for power combining and data transmission measurements, and results of computer modeling of the magic-T and alternative hybrid junctions for improvements in efficiency and power handling capability. The power combiner results presented here are relevant not only to NASA deep space exploration missions, but also to other U.S. Government agency programs.

A broadband high-efficiency Doherty power amplifier using symmetrical devices

NASA Astrophysics Data System (ADS)

Cheng, Zhiqun; Zhang, Ming; Li, Jiangzhou; Liu, Guohua

2018-04-01

This paper proposes a method for broadband and high-efficiency amplification of Doherty power amplifier (DPA) using symmetric devices. In order to achieve the perfect load modulation, the carrier amplifier output circuit total power length is designed to odd multiple of 90°, and the peak amplifier output total power length is designed to even multiple of 180°. The proposed method is demonstrated by designing a broadband high-efficiency DPA using identical 10-W packaged GaN HEMT devices. Measurement results show that over 51% drain efficiency is achieved at 6-dB back-off power, over the frequency band of 1.9–2.4 GHz. Project supported by the National Natural Science Foundation of China (No. 60123456), the Zhejiang Provincial Natural Science Foundation of China (No. LZ16F010001), and the Zhejiang Provincial Public Technology Research Project (No. 2016C31070).

A flexible data fusion architecture for persistent surveillance using ultra-low-power wireless sensor networks

NASA Astrophysics Data System (ADS)

Hanson, Jeffrey A.; McLaughlin, Keith L.; Sereno, Thomas J.

2011-06-01

We have developed a flexible, target-driven, multi-modal, physics-based fusion architecture that efficiently searches sensor detections for targets and rejects clutter while controlling the combinatoric problems that commonly arise in datadriven fusion systems. The informational constraints imposed by long lifetime requirements make systems vulnerable to false alarms. We demonstrate that our data fusion system significantly reduces false alarms while maintaining high sensitivity to threats. In addition, mission goals can vary substantially in terms of targets-of-interest, required characterization, acceptable latency, and false alarm rates. Our fusion architecture provides the flexibility to match these trade-offs with mission requirements unlike many conventional systems that require significant modifications for each new mission. We illustrate our data fusion performance with case studies that span many of the potential mission scenarios including border surveillance, base security, and infrastructure protection. In these studies, we deployed multi-modal sensor nodes - including geophones, magnetometers, accelerometers and PIR sensors - with low-power processing algorithms and low-bandwidth wireless mesh networking to create networks capable of multi-year operation. The results show our data fusion architecture maintains high sensitivities while suppressing most false alarms for a variety of environments and targets.

A high-efficiency high-power-generation system for automobiles

DOE Office of Scientific and Technical Information (OSTI.GOV)

Naidu, M.; Boules, N.; Henry, R.

This paper presents a new scheme for the efficient generation of high electric power demanded for future automobiles. The new system consists of a permanent-magnet (PM) alternator having high-energy MAGNEQUENCH (MQ) magnets and split winding and a novel electronic voltage-regulation scheme. A proof-of-concept system, capable of providing 100/250 A (idle/cruising) at 14 V, has been built and tested in the laboratory with encouraging results. This high output is provided at 15--20 percentage points higher efficiencies than conventional automotive alternators, which translates into considerable fuel economy savings. The system is 8 dB quieter and has a rotor inertia of only 2/3more » that of an equivalent production alternator, thus allowing for a belt drive without excessive slippage.« less

A high-efficiency, high power generation system for automobiles

DOE Office of Scientific and Technical Information (OSTI.GOV)

Naidu, M.; Boules, N.; Henry, R.

The paper presents a new scheme for the efficient generation of high electric power, demands for future automobiles. The new system, consists of a permanent magnet (PM) alternator having high energy MAGNEQUENCH (MQ) magnets and split winding; and a novel electronic voltage regulation scheme. A proof of concept system, capable of providing 100/250 A (idle/cruising) at 14 V, has been built and tested in the laboratory with encouraging results. This high output is provided at 15--20 percentage points higher efficiencies than conventional automotive alternators, which translates into considerable fuel economy savings. The system is 8 dB quieter and has amore » rotor inertia of only 2/3 that of an equivalent production alternator, thus allowing for a belt drive without excessive slippage.« less

Liquid lithium loop system to solve challenging technology issues for fusion power plant

NASA Astrophysics Data System (ADS)

Ono, M.; Majeski, R.; Jaworski, M. A.; Hirooka, Y.; Kaita, R.; Gray, T. K.; Maingi, R.; Skinner, C. H.; Christenson, M.; Ruzic, D. N.

2017-11-01

Steady-state fusion power plant designs present major divertor technology challenges, including high divertor heat flux both in steady-state and during transients. In addition to these concerns, there are the unresolved technology issues of long term dust accumulation and associated tritium inventory and safety issues. It has been suggested that radiation-based liquid lithium (LL) divertor concepts with a modest lithium-loop could provide a possible solution for these outstanding fusion reactor technology issues, while potentially improving reactor plasma performance. The application of lithium (Li) in NSTX resulted in improved H-mode confinement, H-mode power threshold reduction, and reduction in the divertor peak heat flux while maintaining essentially Li-free core plasma operation even during H-modes. These promising results in NSTX and related modeling calculations motivated the radiative liquid lithium divertor concept and its variant, the active liquid lithium divertor concept, taking advantage of the enhanced or non-coronal Li radiation in relatively poorly confined divertor plasmas. To maintain the LL purity in a 1 GW-electric class fusion power plant, a closed LL loop system with a modest circulating capacity of ~1 l s-1 is envisioned. We examined two key technology issues: (1) dust or solid particle removal and (2) real time recovery of tritium from LL while keeping the tritium inventory level to an acceptable level. By running the LL-loop continuously, it can carry the dust particles and impurities generated in the vacuum vessel to the outside where the dust/impurities can be removed by relatively simple dust filter, cold trap and/or centrifugal separation systems. With ~1 l s-1 LL flow, even a small 0.1% dust content by weight (or 0.5 g s-1) suggests that the LL-loop could carry away nearly 16 tons of dust per year. In a 1 GW-electric (or ~3 GW fusion power) fusion power plant, about 0.5 g s-1 of tritium is needed to maintain the fusion fuel cycle

High efficiency and brightness fluorescent organic light emitting diode by triplet-triplet fusion

DOEpatents

Forrest, Stephen; Zhang, Yifan

2015-02-10

A first device is provided. The first device further comprises an organic light emitting device. The organic light emitting device further comprises an anode, a cathode, and an emissive layer disposed between the anode and the cathode. The emissive layer may include an organic host compound and at least one organic emitting compound capable of fluorescent emission at room temperature. Various configurations are described for providing a range of current densities in which T-T fusion dominates over S-T annihilation, leading to very high efficiency fluorescent OLEDs.

High power, high efficiency, continuous-wave supercontinuum generation using standard telecom fibers.

PubMed

Arun, S; Choudhury, Vishal; Balaswamy, V; Prakash, Roopa; Supradeepa, V R

2018-04-02

We demonstrate a simple module for octave spanning continuous-wave supercontinuum generation using standard telecom fiber. This module can accept any high power ytterbium-doped fiber laser as input. The input light is transferred into the anomalous dispersion region of the telecom fiber through a cascade of Raman shifts. A recently proposed Raman laser architecture with distributed feedback efficiently performs these Raman conversions. A spectrum spanning over 1000nm (>1 octave) from 880 to 1900nm is demonstrated. The average power from the supercontinuum is ~34W with a high conversion efficiency of 44%. Input wavelength agility is demonstrated with similar supercontinua over a wide input wavelength range.

High power, high efficiency, continuous-wave supercontinuum generation using standard telecom fibers

NASA Astrophysics Data System (ADS)

Arun, S.; Choudhury, Vishal; Balaswamy, V.; Prakash, Roopa; Supradeepa, V. R.

2018-04-01

We demonstrate a simple module for octave spanning continuous-wave supercontinuum generation using standard telecom fiber. This module can accept any high power Ytterbium-doped fiber laser as input. The input light is transferred into the anomalous dispersion region of the telecom fiber through a cascade of Raman shifts. A recently proposed Raman laser architecture with distributed feedback efficiently performs these Raman conversions. A spectrum spanning over 1000nm(>1 octave) from 880-1900nm is demonstrated. The average power from the supercontinuum is ~34W with a high conversion efficiency of 44%. Input wavelength agility is demonstrated with similar supercontinua over a wide input wavelength range.

High-Efficiency Ka-Band Waveguide Two-Way Asymmetric Power Combiner

NASA Technical Reports Server (NTRS)

Wintucky, E. G.; Simons, R. N.; Freeman, J. C.; Chevalier, C. T.

2011-01-01

NASA is planning a number of Space Exploration, Earth Observation and Space Science missions where Ka-band solid-state power amplifiers (SSPAs) could have a role. Monolithic microwave integrated circuit (MMIC) based SSPAs with output powers on the order of 10 W at Ka-band frequencies would be adequate to satisfy the data transmission rate requirements at the distances involved. MMICs are a type of integrated circuit fabricated on a GaAs wafer, which operates at micro wave frequencies and performs the function of signal amplification. The highest power Ka-band (31.8 to 32.3 GHz) SSPA to have flown in space had an output power of 2.6 W with an overall efficiency of 14.3 percent. This SSPA was built around discrete GaAs pHEMT (high electron mobility transistor) devices and flew aboard the Deep Space One spacecraft. State-of-the-art GaAs pHEMT-based MMIC power amplifiers (PAs) can deliver RF power at Ka-band frequencies anywhere from 3 W with a power added efficiency (PAE) of 32 percent to 6 W with a PAE of 26 percent. However, to achieve power levels higher than 6 W, the output of several MMIC PAs would need to be combined using a high-efficiency power combiner. Conventional binary waveguide power combiners, based on short-slot and magic-T circuits, require MMIC PAs with identical amplitude and phase characteristics for high combining efficiency. However, due to manufacturing process variations, the output powers of the MMIC PAs tend to be unequal, and hence the need to develop unequal power combiners. A two-way asymmetric magic-T based power combiner for MMIC power amplifiers, which can take in unequal inputs, has been successfully designed, fabricated, and characterized over NASA s Deep Space Network (DSN) frequency range of 31.8 to 32.3 GHz. The figure is a transparent view of the a sym - metric combiner that shows the 4-port configuration and the internal structure. The rod, post, and iris are positioned by design to achieve the desired asymmetric power ratio

Volume Bragg grating narrowed high-power and highly efficient cladding-pumped Raman fiber laser.

PubMed

Liu, Jun; Yao, Weichao; Zhao, Chujun; Shen, Deyuan; Fan, Dianyuan

2014-12-10

High-power and highly efficient operation of a single-mode cladding-pumped Raman fiber laser with narrow lasing bandwidth is demonstrated. The spectral narrowing was realized by an external cavity containing a volume Bragg grating with a center wavelength of 1658 nm. A maximum output power of 10.4 W at 1658.3 nm with a spectral linewidth (FWHM) of ∼0.1  nm was obtained for the launched pump power of 18.4 W, corresponding to a slope efficiency of 109% with respect to the launched pump power. Lasing characteristics of free-running operation are also evaluated and discussed.

Recent Trends in Fusion Gyrotron Development at KIT

NASA Astrophysics Data System (ADS)

Gantenbein, G.; Avramidis, K.; Franck, J.; Illy, S.; Ioannidis, Z. C.; Jin, J.; Jelonnek, J.; Kalaria, P.; Pagonakis, I. Gr.; Ruess, S.; Rzesnicki, T.; Thumm, M.; Wu, C.

2017-10-01

ECRH&CD is one of the favorite heating system for magnetically confined nuclear fusion plasmas. KIT is strongly involved in the development of high power gyrotrons for use in ECRH systems for nuclear fusion. KIT is upgrading the sub-components of the existing 2 MW, 170 GHz coaxial-cavity short-pulse gyrotron to support long-pulse operation up to 1 s, all components will be equipped with a specific active cooling system. Two important developments for future high power, highly efficient gyrotrons will be discussed: design of gyrotrons with high operating frequency (˜ 240 GHz) and efficiency enhancement by using advanced collector designs with multi-staged voltage depression.

Phase-I investigation of high-efficiency power amplifiers for 325 and 650 MHz

DOE Office of Scientific and Technical Information (OSTI.GOV)

Raab, Frederick

2018-01-27

This Phase-I SBIR grant investigated techniques for high-efficiency power amplification for DoE particle accelerators such as Project X that operate at 325 and 650 MHz. The recommended system achieves high efficiency, high reliability, and hot-swap capability by integrating class-F power amplifiers, class-S modulators, power combiners, and a digital signal processor. Experimental evaluations demonstrate the production of 120 W per transistor with overall efficiencies from 86 percent at 325 MHz and 80 percent at 650 MHz.

Propulsion and Power Generation Capabilities of a Dense Plasma Focus (DPF) Fusion System for Future Military Aerospace Vehicles

DOE Office of Scientific and Technical Information (OSTI.GOV)

Knecht, Sean D.; Mead, Franklin B.; Thomas, Robert E.

2006-01-20

The objective of this study was to perform a parametric evaluation of the performance and interface characteristics of a dense plasma focus (DPF) fusion system in support of a USAF advanced military aerospace vehicle concept study. This vehicle is an aerospace plane that combines clean 'aneutronic' dense plasma focus (DPF) fusion power and propulsion technology, with advanced 'lifting body'-like airframe configurations utilizing air-breathing MHD propulsion and power technology within a reusable single-stage-to-orbit (SSTO) vehicle. The applied approach was to evaluate the fusion system details (geometry, power, T/W, system mass, etc.) of a baseline p-11B DPF propulsion device with Q =more » 3.0 and thruster efficiency, {eta}prop = 90% for a range of thrust, Isp and capacitor specific energy values. The baseline details were then kept constant and the values of Q and {eta}prop were varied to evaluate excess power generation for communication systems, pulsed-train plasmoid weapons, ultrahigh-power lasers, and gravity devices. Thrust values were varied between 100 kN and 1,000 kN with Isp of 1,500 s and 2,000 s, while capacitor specific energy was varied from 1 - 15 kJ/kg. Q was varied from 3.0 to 6.0, resulting in gigawatts of excess power. Thruster efficiency was varied from 0.9 to 1.0, resulting in hundreds of megawatts of excess power. Resulting system masses were on the order of 10's to 100's of metric tons with thrust-to-weight ratios ranging from 2.1 to 44.1, depending on capacitor specific energy. Such a high thrust/high Isp system with a high power generation capability would allow military versatility in sub-orbital space, as early as 2025, and beyond as early as 2050. This paper presents the results that coincide with a total system mass between 15 and 20 metric tons.« less

ADX: a high field, high power density, advanced divertor and RF tokamak

NASA Astrophysics Data System (ADS)

LaBombard, B.; Marmar, E.; Irby, J.; Terry, J. L.; Vieira, R.; Wallace, G.; Whyte, D. G.; Wolfe, S.; Wukitch, S.; Baek, S.; Beck, W.; Bonoli, P.; Brunner, D.; Doody, J.; Ellis, R.; Ernst, D.; Fiore, C.; Freidberg, J. P.; Golfinopoulos, T.; Granetz, R.; Greenwald, M.; Hartwig, Z. S.; Hubbard, A.; Hughes, J. W.; Hutchinson, I. H.; Kessel, C.; Kotschenreuther, M.; Leccacorvi, R.; Lin, Y.; Lipschultz, B.; Mahajan, S.; Minervini, J.; Mumgaard, R.; Nygren, R.; Parker, R.; Poli, F.; Porkolab, M.; Reinke, M. L.; Rice, J.; Rognlien, T.; Rowan, W.; Shiraiwa, S.; Terry, D.; Theiler, C.; Titus, P.; Umansky, M.; Valanju, P.; Walk, J.; White, A.; Wilson, J. R.; Wright, G.; Zweben, S. J.

2015-05-01

The MIT Plasma Science and Fusion Center and collaborators are proposing a high-performance Advanced Divertor and RF tokamak eXperiment (ADX)—a tokamak specifically designed to address critical gaps in the world fusion research programme on the pathway to next-step devices: fusion nuclear science facility (FNSF), fusion pilot plant (FPP) and/or demonstration power plant (DEMO). This high-field (⩾6.5 T, 1.5 MA), high power density facility (P/S ˜ 1.5 MW m-2) will test innovative divertor ideas, including an ‘X-point target divertor’ concept, at the required performance parameters—reactor-level boundary plasma pressures, magnetic field strengths and parallel heat flux densities entering into the divertor region—while simultaneously producing high-performance core plasma conditions that are prototypical of a reactor: equilibrated and strongly coupled electrons and ions, regimes with low or no torque, and no fuelling from external heating and current drive systems. Equally important, the experimental platform will test innovative concepts for lower hybrid current drive and ion cyclotron range of frequency actuators with the unprecedented ability to deploy launch structures both on the low-magnetic-field side and the high-magnetic-field side—the latter being a location where energetic plasma-material interactions can be controlled and favourable RF wave physics leads to efficient current drive, current profile control, heating and flow drive. This triple combination—advanced divertors, advanced RF actuators, reactor-prototypical core plasma conditions—will enable ADX to explore enhanced core confinement physics, such as made possible by reversed central shear, using only the types of external drive systems that are considered viable for a fusion power plant. Such an integrated demonstration of high-performance core-divertor operation with steady-state sustainment would pave the way towards an attractive pilot plant, as envisioned in the ARC concept

Development of high-efficiency power amplifiers for PIP2 (Project X), Phase II

DOE Office of Scientific and Technical Information (OSTI.GOV)

Raab, Frederick

The Fermi Lab PIP II (formerly Project X) accelerator will require the generation of over a megawatt of radio-frequency (RF) power at 325 and 650 MHz. This Phase-II SBIR grant developed techniques to generate this RF power efficienly. The basis of this approach is a system comprising high-efficiency RF power amplifiers, high-efficiency class-S modulators to maintain efficiency at all power levels, and low-loss power combiners. A digital signal processor adjusts signal parameters to obtain the maximum efficiency while producing a signal of the desired amplitude and phase. Components of 4-kW prototypes were designed, assembled, and tested. The 500-W modules producemore » signals at 325 MHz with an overall efficiency of 83 percent and signals at 650 MHz with an overall efficiency of 79 percent. This efficiency is nearly double that available from conventional techniques, which makes it possible to cut the power consumption nearly in half. The system is designed to be scalable to the multi-kilowatt level and can be adapted to other DoE applications.« less

Fusion powered human transport to Mars (UWFR94)

NASA Technical Reports Server (NTRS)

Cappellari, John; Grota, Susan; Hagedorn, David; Hirai, Yoshi; Remmel, Mark; Schmidt, Deanna; Sveum, Matt; Wandow, Helena

1994-01-01

In the future, two important technological dreams will have become reality: fusion will be a viable power source, and human settlement on Mars will be feasible, desirable, and even necessary. Merging these two concepts is especially attractive for the aerospace engineer because of the high specific power that will be possible with fusion (on the order 10 kW/kg). The UWFR94, a large, fusion-powered, human-transport ship, is designed to transport 100 passengers between earth and Mars in approximately thirty days. This relatively short transit time, which mitigates the need for artificial gravity, is made possible by a Polywell inertial electrostatic fusion reactor capable of 20 kW/kg. The mass of each reactor is 37 metric tons and the fuel used is (3)He-(3)He. The electricity generated drives the propulsion system, composed of nine ion thrusters and 780 tons of xenon propellant. The payload consists of three independent, identical cylinders housing the crew, and has a mass of approximately 400 tons. The aluminum cylinders' radius and length are 3 and 12 meters, respectively, with a thickness of 6 cm (15 cm in the solar flare safe rooms). Atmospheric reentry is avoided by constructing and repairing the UWFR94 in space, and by transferring crew and cargo to shuttle-like vehicles for transportation to the planet upon arrival.

A high efficiency C-band internally-matched harmonic tuning GaN power amplifier

NASA Astrophysics Data System (ADS)

Lu, Y.; Zhao, B. C.; Zheng, J. X.; Zhang, H. S.; Zheng, X. F.; Ma, X. H.; Hao, Y.; Ma, P. J.

2016-09-01

In this paper, a high efficiency C-band gallium nitride (GaN) internally-matched power amplifier (PA) is presented. This amplifier consists of 2-chips of self-developed GaN high-electron mobility transistors (HEMTs) with 16 mm total gate width on SiC substrate. New harmonic manipulation circuits are induced both in the input and output matching networks for high efficiency matching at fundamental and 2nd-harmonic frequency, respectively. The developed amplifier has achieved 72.1% power added efficiency (PAE) with 107.4 W output power at 5 GHz. To the best of our knowledge, this amplifier exhibits the highest PAE in C-band GaN HEMT amplifiers with over 100 W output power. Additionally, 1000 hours' aging test reveals high reliability for practical applications.

Apparatus and method for extracting power from energetic ions produced in nuclear fusion

DOEpatents

Fisch, N.J.; Rax, J.M.

1994-12-20

An apparatus and method of extracting power from energetic ions produced by nuclear fusion in a toroidal plasma to enhance respectively the toroidal plasma current and fusion reactivity. By injecting waves of predetermined frequency and phase traveling substantially in a selected poloidal direction within the plasma, the energetic ions become diffused in energy and space such that the energetic ions lose energy and amplify the waves. The amplified waves are further adapted to travel substantially in a selected toroidal direction to increase preferentially the energy of electrons traveling in one toroidal direction which, in turn, enhances or generates a toroidal plasma current. In an further adaptation, the amplified waves can be made to preferentially increase the energy of fuel ions within the plasma to enhance the fusion reactivity of the fuel ions. The described direct, or in situ, conversion of the energetic ion energy provides an efficient and economical means of delivering power to a fusion reactor. 4 figures.

Apparatus and method for extracting power from energetic ions produced in nuclear fusion

DOEpatents

Fisch, Nathaniel J.; Rax, Jean M.

1994-01-01

An apparatus and method of extracting power from energetic ions produced by nuclear fusion in a toroidal plasma to enhance respectively the toroidal plasma current and fusion reactivity. By injecting waves of predetermined frequency and phase traveling substantially in a selected poloidal direction within the plasma, the energetic ions become diffused in energy and space such that the energetic ions lose energy and amplify the waves. The amplified waves are further adapted to travel substantially in a selected toroidal direction to increase preferentially the energy of electrons traveling in one toroidal direction which, in turn, enhances or generates a toroidal plasma current. In an further adaptation, the amplified waves can be made to preferentially increase the energy of fuel ions within the plasma to enhance the fusion reactivity of the fuel ions. The described direct, or in situ, conversion of the energetic ion energy provides an efficient and economical means of delivering power to a fusion reactor.

Liquid lithium loop system to solve challenging technology issues for fusion power plant

DOE PAGES

Ono, Masayuki; Majeski, Richard P.; Jaworski, Michael A.; ...

2017-07-12

Here, steady-state fusion power plant designs present major divertor technology challenges, including high divertor heat flux both in steady-state and during transients. In addition to these concerns, there are the unresolved technology issues of long term dust accumulation and associated tritium inventory and safety issues. It has been suggested that radiation-based liquid lithium (LL) divertor concepts with a modest lithium-loop could provide a possible solution for these outstanding fusion reactor technology issues, while potentially improving reactor plasma performance. The application of lithium (Li) in NSTX resulted in improved H-mode confinement, H-mode power threshold reduction, and reduction in the divertor peakmore » heat flux while maintaining essentially Li-free core plasma operation even during H-modes. These promising results in NSTX and related modeling calculations motivated the radiative liquid lithium divertor (RLLD) concept and its variant, the active liquid lithium divertor concept (ARLLD), taking advantage of the enhanced or non-coronal Li radiation in relatively poorly confined divertor plasmas. To maintain the LL purity in a 1 GW-electric class fusion power plant, a closed LL loop system with a modest circulating capacity of ~ 1 liter/second (l/sec) is envisioned. We examined two key technology issues: 1) dust or solid particle removal and 2) real time recovery of tritium from LL while keeping the tritium inventory level to an acceptable level. By running the LL-loop continuously, it can carry the dust particles and impurities generated in the vacuum vessel to the outside where the dust / impurities can be removed by relatively simple dust filter, cold trap and/or centrifugal separation systems. With ~ 1 l/sec LL flow, even a small 0.1% dust content by weight (or 0.5 g per sec) suggests that the LL-loop could carry away nearly 16 tons of dust per year. In a 1 GW-electric (or ~ 3 GW fusion power) fusion power plant, about 0.5 g / sec of

Liquid lithium loop system to solve challenging technology issues for fusion power plant

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ono, Masayuki; Majeski, Richard P.; Jaworski, Michael A.

Here, steady-state fusion power plant designs present major divertor technology challenges, including high divertor heat flux both in steady-state and during transients. In addition to these concerns, there are the unresolved technology issues of long term dust accumulation and associated tritium inventory and safety issues. It has been suggested that radiation-based liquid lithium (LL) divertor concepts with a modest lithium-loop could provide a possible solution for these outstanding fusion reactor technology issues, while potentially improving reactor plasma performance. The application of lithium (Li) in NSTX resulted in improved H-mode confinement, H-mode power threshold reduction, and reduction in the divertor peakmore » heat flux while maintaining essentially Li-free core plasma operation even during H-modes. These promising results in NSTX and related modeling calculations motivated the radiative liquid lithium divertor (RLLD) concept and its variant, the active liquid lithium divertor concept (ARLLD), taking advantage of the enhanced or non-coronal Li radiation in relatively poorly confined divertor plasmas. To maintain the LL purity in a 1 GW-electric class fusion power plant, a closed LL loop system with a modest circulating capacity of ~ 1 liter/second (l/sec) is envisioned. We examined two key technology issues: 1) dust or solid particle removal and 2) real time recovery of tritium from LL while keeping the tritium inventory level to an acceptable level. By running the LL-loop continuously, it can carry the dust particles and impurities generated in the vacuum vessel to the outside where the dust / impurities can be removed by relatively simple dust filter, cold trap and/or centrifugal separation systems. With ~ 1 l/sec LL flow, even a small 0.1% dust content by weight (or 0.5 g per sec) suggests that the LL-loop could carry away nearly 16 tons of dust per year. In a 1 GW-electric (or ~ 3 GW fusion power) fusion power plant, about 0.5 g / sec of

High power-efficient asynchronous SAR ADC for IoT devices

NASA Astrophysics Data System (ADS)

Zhang, Beichen; Yao, Bingbing; Liu, Liyuan; Liu, Jian; Wu, Nanjian

2017-10-01

This paper presents a power-efficient 100-MS/s, 10-bit asynchronous successive approximation register (SAR) ADC. It includes an on-chip reference buffer and the total power dissipation is 6.8 mW. To achieve high performance with high power-efficiency in the proposed ADC, bootstrapped switch, redundancy, set-and-down switching approach, dynamic comparator and dynamic logic techniques are employed. The prototype was fabricated using 65 nm standard CMOS technology. At a 1.2-V supply and 100 MS/s, the ADC achieves an SNDR of 56.2 dB and a SFDR of 65.1 dB. The ADC core consumes only 3.1 mW, resulting in a figure of merit (FOM) of 30.27 fJ/conversionstep and occupies an active area of only 0.009 mm2.

Design Considerations for Clean QED Fusion Propulsion Systems

NASA Astrophysics Data System (ADS)

Bussard, Robert W.; Jameson, Lorin W.

1994-07-01

The direct production of electric power appears possible from fusion reactions between fuels whose products consist solely of charged particles and thus do not present radiation hazards from energetic neutron production, as do reactions involving deuteron-bearing fuels. Among these are the fuels p, 11B, 3He, and 6Li. All of these can be ``burned'' in inertial-electrostatic-fusion (IEF) devices to power QED fusion-electric rocket engines. These IEF sources provide direct-converted electrical power at high voltage (MeV) to drive e-beams for efficient propellant heating to extreme temperatures, with resulting high specific impulse performance capabilities. IEF/QED engine systems using p11B can outperform all other advanced concepts for controlled fusion propulsion by 2-3 orders of magnitude, while 6Li6Li fusion yields one order of magnitude less advance. Either of these fusion rocket propulsion systems can provide very rapid transit for solar system missions, with high payload fractions in single-stage vehicles. The 3He3He reaction can not be used practically for direct electric conversion because of the wide spread in energy of its fusion products. However, it may eventually prove useful for thermal/electrical power generation in central station power plants, or for direct-fusion-product (DFP) propellant heatingin advanced deep-space rocket engines.

IEC fusion: The future power and propulsion system for space

NASA Astrophysics Data System (ADS)

Hammond, Walter E.; Coventry, Matt; Hanson, John; Hrbud, Ivana; Miley, George H.; Nadler, Jon

2000-01-01

Rapid access to any point in the solar system requires advanced propulsion concepts that will provide extremely high specific impulse, low specific power, and a high thrust-to-power ratio. Inertial Electrostatic Confinement (IEC) fusion is one of many exciting concepts emerging through propulsion and power research in laboratories across the nation which will determine the future direction of space exploration. This is part of a series of papers that discuss different applications of the Inertial Electrostatic Confinement (IEC) fusion concept for both in-space and terrestrial use. IEC will enable tremendous advances in faster travel times within the solar system. The technology is currently under investigation for proof of concept and transitioning into the first prototype units for commercial applications. In addition to use in propulsion for space applications, terrestrial applications include desalinization plants, high energy neutron sources for radioisotope generation, high flux sources for medical applications, proton sources for specialized medical applications, and tritium production. .

Efficient, High-Power Mid-Infrared Laser for National Securityand Scientific Applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kiani, Leily S.

The LLNL fiber laser group developed a unique short-wave-infrared, high-pulse energy, highaverage- power fiber based laser. This unique laser source has been used in combination with a nonlinear frequency converter to generate wavelengths, useful for remote sensing and other applications in the mid-wave infrared (MWIR). Sources with high average power and high efficiency in this MWIR wavelength region are not yet available with the size, weight, and power requirements or energy efficiency necessary for future deployment. The LLNL developed Fiber Laser Pulsed Source (FiLPS) design was adapted to Erbium doped silica fibers for 1.55 μm pumping of Cadmium Silicon Phosphidemore » (CSP). We have demonstrated, for the first time optical parametric amplification of 2.4 μm light via difference frequency generation using CSP with an Erbium doped fiber source. In addition, for efficiency comparison purposes, we also demonstrated direct optical parametric generation (OPG) as well as optical parametric oscillation (OPO).« less

Micro-engineered first wall tungsten armor for high average power laser fusion energy systems

NASA Astrophysics Data System (ADS)

Sharafat, Shahram; Ghoniem, Nasr M.; Anderson, Michael; Williams, Brian; Blanchard, Jake; Snead, Lance; HAPL Team

2005-12-01

The high average power laser program is developing an inertial fusion energy demonstration power reactor with a solid first wall chamber. The first wall (FW) will be subject to high energy density radiation and high doses of high energy helium implantation. Tungsten has been identified as the candidate material for a FW armor. The fundamental concern is long term thermo-mechanical survivability of the armor against the effects of high temperature pulsed operation and exfoliation due to the retention of implanted helium. Even if a solid tungsten armor coating would survive the high temperature cyclic operation with minimal failure, the high helium implantation and retention would result in unacceptable material loss rates. Micro-engineered materials, such as castellated structures, plasma sprayed nano-porous coatings and refractory foams are suggested as a first wall armor material to address these fundamental concerns. A micro-engineered FW armor would have to be designed with specific geometric features that tolerate high cyclic heating loads and recycle most of the implanted helium without any significant failure. Micro-engineered materials are briefly reviewed. In particular, plasma-sprayed nano-porous tungsten and tungsten foams are assessed for their potential to accommodate inertial fusion specific loads. Tests show that nano-porous plasma spray coatings can be manufactured with high permeability to helium gas, while retaining relatively high thermal conductivities. Tungsten foams where shown to be able to overcome thermo-mechanical loads by cell rotation and deformation. Helium implantation tests have shown, that pulsed implantation and heating releases significant levels of implanted helium. Helium implantation and release from tungsten was modeled using an expanded kinetic rate theory, to include the effects of pulsed implantations and thermal cycles. Although, significant challenges remain micro-engineered materials are shown to constitute potential

The effect of multispectral image fusion enhancement on human efficiency.

PubMed

Bittner, Jennifer L; Schill, M Trent; Mohd-Zaid, Fairul; Blaha, Leslie M

2017-01-01

The visual system can be highly influenced by changes to visual presentation. Thus, numerous techniques have been developed to augment imagery in an attempt to improve human perception. The current paper examines the potential impact of one such enhancement, multispectral image fusion, where imagery captured in varying spectral bands (e.g., visible, thermal, night vision) is algorithmically combined to produce an output to strengthen visual perception. We employ ideal observer analysis over a series of experimental conditions to (1) establish a framework for testing the impact of image fusion over the varying aspects surrounding its implementation (e.g., stimulus content, task) and (2) examine the effectiveness of fusion on human information processing efficiency in a basic application. We used a set of rotated Landolt C images captured with a number of individual sensor cameras and combined across seven traditional fusion algorithms (e.g., Laplacian pyramid, principal component analysis, averaging) in a 1-of-8 orientation task. We found that, contrary to the idea of fused imagery always producing a greater impact on perception, single-band imagery can be just as influential. Additionally, efficiency data were shown to fluctuate based on sensor combination instead of fusion algorithm, suggesting the need for examining multiple factors to determine the success of image fusion. Our use of ideal observer analysis, a popular technique from the vision sciences, provides not only a standard for testing fusion in direct relation to the visual system but also allows for comparable examination of fusion across its associated problem space of application.

Fusion Breeding for Sustainable, Mid Century, Carbon Free Power

NASA Astrophysics Data System (ADS)

Manheimer, Wallace

2015-11-01

If ITER achieves Q ~10, it is still very far from useful fusion. The fusion power, and the driver power will allow only a small amount of power to be delivered, <~50MW for an ITER scale tokamak. It is unlikely, considering ``conservative design rules'' that tokamaks can ever be economical pure fusion power producers. Considering the status of other magnetic fusion concepts, it is also very unlikely that any alternate concept will either. Laser fusion does not seem to be constrained by any conservative design rules, but considering the failure of NIF to achhieve ignition, at this point it has many more obstacles to overcome than magnetic fusion. One way out of this dilemma is to use an ITER size tokamak, or a NIF size laser, as a fuel breeder for searate nuclear reactors. Hence ITER and NIF become ends in themselves, instead of steps to who knows what DEMO decades later. Such a tokamak can easily live within the consrtaints of conservative design rules. This has led the author to propose ``The Energy Park'' a sustainable, carbon free, economical, and environmently viable power source without prolifertion risk. It is one fusion breeder fuels 5 conventional nuclear reactors, and one fast neutron reactor burns the actinide wastes.

The NASA-Lewis program on fusion energy for space power and propulsion, 1958-1978

NASA Technical Reports Server (NTRS)

Schulze, Norman R.; Roth, J. Reece

1990-01-01

An historical synopsis is provided of the NASA-Lewis research program on fusion energy for space power and propulsion systems. It was initiated to explore the potential applications of fusion energy to space power and propulsion systems. Some fusion related accomplishments and program areas covered include: basic research on the Electric Field Bumpy Torus (EFBT) magnetoelectric fusion containment concept, including identification of its radial transport mechanism and confinement time scaling; operation of the Pilot Rig mirror machine, the first superconducting magnet facility to be used in plasma physics or fusion research; operation of the Superconducting Bumpy Torus magnet facility, first used to generate a toroidal magnetic field; steady state production of neutrons from DD reactions; studies of the direct conversion of plasma enthalpy to thrust by a direct fusion rocket via propellant addition and magnetic nozzles; power and propulsion system studies, including D(3)He power balance, neutron shielding, and refrigeration requirements; and development of large volume, high field superconducting and cryogenic magnet technology.

High-Efficiency Power Module

NASA Technical Reports Server (NTRS)

Simons, Rainee N (Inventor); Wintucky, Edwin G (Inventor)

2013-01-01

One or more embodiments of the present invention pertain to an all solid-state microwave power module. The module includes a plurality of solid-state amplifiers configured to amplify a signal using a low power stage, a medium power stage, and a high power stage. The module also includes a power conditioner configured to activate a voltage sequencer (e.g., bias controller) when power is received from a power source. The voltage sequencer is configured to sequentially apply voltage to a gate of each amplifier and sequentially apply voltage to a drain of each amplifier.

High-Efficiency Power Module

NASA Technical Reports Server (NTRS)

Simons, Rainee N. (Inventor); Wintucky, Edwin G. (Inventor)

2015-01-01

One or more embodiments of the present invention pertain to an all solid-state microwave power module. The module includes a plurality of solid-state amplifiers configured to amplify a signal using a low power stage, a medium power stage, and a high power stage. The module also includes a power conditioner configured to activate a voltage sequencer (e.g., bias controller) when power is received from a power source. The voltage sequencer is configured to sequentially apply voltage to a gate of each amplifier and sequentially apply voltage to a drain of each amplifier.

Control of a laser inertial confinement fusion-fission power plant

DOEpatents

Moses, Edward I.; Latkowski, Jeffery F.; Kramer, Kevin J.

2015-10-27

A laser inertial-confinement fusion-fission energy power plant is described. The fusion-fission hybrid system uses inertial confinement fusion to produce neutrons from a fusion reaction of deuterium and tritium. The fusion neutrons drive a sub-critical blanket of fissile or fertile fuel. A coolant circulated through the fuel extracts heat from the fuel that is used to generate electricity. The inertial confinement fusion reaction can be implemented using central hot spot or fast ignition fusion, and direct or indirect drive. The fusion neutrons result in ultra-deep burn-up of the fuel in the fission blanket, thus enabling the burning of nuclear waste. Fuels include depleted uranium, natural uranium, enriched uranium, spent nuclear fuel, thorium, and weapons grade plutonium. LIFE engines can meet worldwide electricity needs in a safe and sustainable manner, while drastically shrinking the highly undesirable stockpiles of depleted uranium, spent nuclear fuel and excess weapons materials.

'Squeezing' near-field thermal emission for ultra-efficient high-power thermophotovoltaic conversion.

PubMed

Karalis, Aristeidis; Joannopoulos, J D

2016-07-01

We numerically demonstrate near-field planar ThermoPhotoVoltaic systems with very high efficiency and output power, at large vacuum gaps. Example performances include: at 1200 °K emitter temperature, output power density 2 W/cm(2) with ~47% efficiency at 300 nm vacuum gap; at 2100 °K, 24 W/cm(2) with ~57% efficiency at 200 nm gap; and, at 3000 °K, 115 W/cm(2) with ~61% efficiency at 140 nm gap. Key to this striking performance is a novel photonic design forcing the emitter and cell single modes to cros resonantly couple and impedance-match just above the semiconductor bandgap, creating there a 'squeezed' narrowband near-field emission spectrum. Specifically, we employ surface-plasmon-polariton thermal emitters and silver-backed semiconductor-thin-film photovoltaic cells. The emitter planar plasmonic nature allows for high-power and stable high-temperature operation. Our simulations include modeling of free-carrier absorption in both cell electrodes and temperature dependence of the emitter properties. At high temperatures, the efficiency enhancement via resonant mode cross-coupling and matching can be extended to even higher power, by appropriately patterning the silver back electrode to enforce also an absorber effective surface-plasmon-polariton mode. Our proposed designs can therefore lead the way for mass-producible and low-cost ThermoPhotoVoltaic micro-generators and solar cells.

A high efficiency PWM CMOS class-D audio power amplifier

NASA Astrophysics Data System (ADS)

Zhangming, Zhu; Lianxi, Liu; Yintang, Yang; Han, Lei

2009-02-01

Based on the difference close-loop feedback technique and the difference pre-amp, a high efficiency PWM CMOS class-D audio power amplifier is proposed. A rail-to-rail PWM comparator with window function has been embedded in the class-D audio power amplifier. Design results based on the CSMC 0.5 μm CMOS process show that the max efficiency is 90%, the PSRR is -75 dB, the power supply voltage range is 2.5-5.5 V, the THD+N in 1 kHz input frequency is less than 0.20%, the quiescent current in no load is 2.8 mA, and the shutdown current is 0.5 μA. The active area of the class-D audio power amplifier is about 1.47 × 1.52 mm2. With the good performance, the class-D audio power amplifier can be applied to several audio power systems.

Burning high-level TRU waste in fusion fission reactors

NASA Astrophysics Data System (ADS)

Shen, Yaosong

2016-09-01

Recently, the concept of actinide burning instead of a once-through fuel cycle for disposing spent nuclear fuel seems to get much more attention. A new method of burning high-level transuranic (TRU) waste combined with Thorium-Uranium (Th-U) fuel in the subcritical reactors driven by external fusion neutron sources is proposed in this paper. The thorium-based TRU fuel burns all of the long-lived actinides via a hard neutron spectrum while outputting power. A one-dimensional model of the reactor concept was built by means of the ONESN_BURN code with new data libraries. The numerical results included actinide radioactivity, biological hazard potential, and much higher burnup rate of high-level transuranic waste. The comparison of the fusion-fission reactor with the thermal reactor shows that the harder neutron spectrum is more efficient than the soft. The Th-U cycle produces less TRU, less radiotoxicity and fewer long-lived actinides. The Th-U cycle provides breeding of 233U with a long operation time (>20 years), hence significantly reducing the reactivity swing while improving safety and burnup.

Indirect drive targets for fusion power

DOEpatents

Amendt, Peter A.; Miles, Robin R.

2016-10-11

A hohlraum for an inertial confinement fusion power plant is disclosed. The hohlraum includes a generally cylindrical exterior surface, and an interior rugby ball-shaped surface. Windows over laser entrance holes at each end of the hohlraum enclose inert gas. Infrared reflectors on opposite sides of the central point reflect fusion chamber heat away from the capsule. P2 shields disposed on the infrared reflectors help assure an enhanced and more uniform x-ray bath for the fusion fuel capsule.

Advanced Power Sources for Space Missions

DTIC Science & Technology

1989-01-01

Range indicate that extremely high power levels hav- ing fast time-ramping capabilities must be provided during the tests. Only highly efficient prime...system efficiency results from advantages in thermal storage versus battery storage and from the increased conversion efficiency of a solar-dynamic... thermal manage- ment, power flow, and voltage levels, and may be in the same power range already experienced in the very- high -power radar and fusion

Technology for radiation efficiency measurement of high-power halogen tungsten lamp used in calibration of high-energy laser energy meter.

PubMed

Wei, Ji Feng; Hu, Xiao Yang; Sun, Li Qun; Zhang, Kai; Chang, Yan

2015-03-20

The calibration method using a high-power halogen tungsten lamp as a calibration source has many advantages such as strong equivalence and high power, so it is very fit for the calibration of high-energy laser energy meters. However, high-power halogen tungsten lamps after power-off still reserve much residual energy and continually radiate energy, which is difficult to be measured. Two measuring systems were found to solve the problems. One system is composed of an integrating sphere and two optical spectrometers, which can accurately characterize the radiative spectra and power-time variation of the halogen tungsten lamp. This measuring system was then calibrated using a normal halogen tungsten lamp made of the same material as the high-power halogen tungsten lamp. In this way, the radiation efficiency of the halogen tungsten lamp after power-off can be quantitatively measured. In the other measuring system, a wide-spectrum power meter was installed far away from the halogen tungsten lamp; thus, the lamp can be regarded as a point light source. The radiation efficiency of residual energy from the halogen tungsten lamp was computed on the basis of geometrical relations. The results show that the halogen tungsten lamp's radiation efficiency was improved with power-on time but did not change under constant power-on time/energy. All the tested halogen tungsten lamps reached 89.3% of radiation efficiency at 50 s after power-on. After power-off, the residual energy in the halogen tungsten lamp gradually dropped to less than 10% of the initial radiation power, and the radiation efficiency changed with time. The final total radiation energy was decided by the halogen tungsten lamp's radiation efficiency, the radiation efficiency of residual energy, and the total power consumption. The measuring uncertainty of total radiation energy was 2.4% (here, the confidence factor is two).

Multi-mode multi-band power amplifier module with high low-power efficiency

NASA Astrophysics Data System (ADS)

Xuguang, Zhang; Jie, Jin

2015-10-01

Increasingly, mobile communications standards require high power efficiency and low currents in the low power mode. This paper proposes a fully-integrated multi-mode and multi-band power amplifier module (PAM) to meet these requirements. A dual-path PAM is designed for high-power mode (HPM), medium-power mode (MPM), and low-power mode (LPM) operations without any series switches for different mode selection. Good performance and significant current saving can be achieved by using an optimized load impedance design for each power mode. The PAM is tapeout with the InGaP/GaAs heterojunction bipolar transistor (HBT) process and the 0.18-μm complementary metal-oxide semiconductor (CMOS) process. The test results show that the PAM achieves a very low quiescent current of 3 mA in LPM. Meanwhile, across the 1.7-2.0 GHz frequency, the PAM performs well. In HPM, the output power is 28 dBm with at least 39.4% PAE and -40 dBc adjacent channel leakage ratio 1 (ACLR1). In MPM, the output power is 17 dBm, with at least 21.3% PAE and -43 dBc ACLR1. In LPM, the output power is 8 dBm, with at least 18.2% PAE and -40 dBc ACLR1. Project supported by the National Natural Science Foundation of China (No. 61201244).

A high-efficiency tunable TEM-TE11 mode converter for high-power microwave applications

NASA Astrophysics Data System (ADS)

Wang, Xiao-Yu; Fan, Yu-Wei; Shu, Ting; Yuan, Cheng-wei; Zhang, Qiang

2017-03-01

The tunable high power microwave source (HPM's) is considered to be an important research direction. However, the corresponding mode converter has been researched little. In this paper, a high-efficiency tunable mode converter (HETMC) is investigated for high-power microwave applications. The HETMC that is consisted of coaxial inner and outer conductors, with four metal plates arranged radially, at 90° in the coaxial gap, and matching rods can transform coaxial transverse electromagnetic (TEM) mode to TE11 coaxial waveguide mode. The results show that adjusting the length of the downstream plate, and the distance between the rods installed upstream and the closest edges of the plates, can improve the conversion efficiency and bandwidth remarkably. Moreover, when the frequency ranges from 1.63 GHz to 2.12 GHz, the conversion efficiency is above 95% between 1.63 GHz and 2.12 GHz with a bandwidth of 26.1%. Besides, the unwished reflection and transmission can be eliminated effectively in the HETMC.

Advanced Fusion Reactors for Space Propulsion and Power Systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chapman, John J.

In recent years the methodology proposed for conversion of light elements into energy via fusion has made steady progress. Scientific studies and engineering efforts in advanced fusion systems designs have introduced some new concepts with unique aspects including consideration of Aneutronic fuels. The plant parameters for harnessing aneutronic fusion appear more exigent than those required for the conventional fusion fuel cycle. However aneutronic fusion propulsion plants for Space deployment will ultimately offer the possibility of enhanced performance from nuclear gain as compared to existing ionic engines as well as providing a clean solution to Planetary Protection considerations and requirements. Protonmore » triggered 11Boron fuel (p- 11B) will produce abundant ion kinetic energy for In-Space vectored thrust. Thus energetic alpha particles' exhaust momentum can be used directly to produce high Isp thrust and also offer possibility of power conversion into electricity. p-11B is an advanced fusion plant fuel with well understood reaction kinematics but will require some new conceptual thinking as to the most effective implementation.« less

Advanced Fusion Reactors for Space Propulsion and Power Systems

NASA Technical Reports Server (NTRS)

Chapman, John J.

2011-01-01

In recent years the methodology proposed for conversion of light elements into energy via fusion has made steady progress. Scientific studies and engineering efforts in advanced fusion systems designs have introduced some new concepts with unique aspects including consideration of Aneutronic fuels. The plant parameters for harnessing aneutronic fusion appear more exigent than those required for the conventional fusion fuel cycle. However aneutronic fusion propulsion plants for Space deployment will ultimately offer the possibility of enhanced performance from nuclear gain as compared to existing ionic engines as well as providing a clean solution to Planetary Protection considerations and requirements. Proton triggered 11Boron fuel (p- 11B) will produce abundant ion kinetic energy for In-Space vectored thrust. Thus energetic alpha particles "exhaust" momentum can be used directly to produce high ISP thrust and also offer possibility of power conversion into electricity. p- 11B is an advanced fusion plant fuel with well understood reaction kinematics but will require some new conceptual thinking as to the most effective implementation.

Fusion for Space Propulsion

NASA Technical Reports Server (NTRS)

Thio, Y. C. Francis; Schmidt, George R.; Santarius, John F.; Turchi, Peter J.; Siemon, Richard E.; Rodgers, Stephen L. (Technical Monitor)

2002-01-01

The need for fusion propulsion for interplanetary flights is discussed. For a propulsion system, there are three important system attributes: (1) The absolute amount of energy available, (2) the propellant exhaust velocity, and (3) the jet power per unit mass of the propulsion system (specific power). For efficient and affordable human exploration of the solar system, propellant exhaust velocity in excess of 100 km/s and specific power in excess of 10 kW/kg are required. Chemical combustion obviously cannot meet the requirement in propellant exhaust velocity. Nuclear fission processes typically result in producing energy in the form of heat that needs to be manipulated at temperatures limited by materials to about 2,800 K. Using the fission energy to heat a low atomic weight propellant produces propellant velocity of the order of 10 kinds. Alternatively the fission energy can be converted into electricity that is used to accelerate particles to high exhaust velocity. However, the necessary power conversion and conditioning equipment greatly increases the mass of the propulsion system. Fundamental considerations in waste heat rejection and power conditioning in a fission electric propulsion system place a limit on its jet specific power to the order of about 0.2 kW/kg. If fusion can be developed for propulsion, it appears to have the best of all worlds - it can provide the largest absolute amount of energy, the propellant exhaust velocity (> 100 km/s), and the high specific jet power (> 10 kW/kg). An intermediate step towards fusion propulsion might be a bimodal system in which a fission reactor is used to provide some of the energy to drive a fusion propulsion unit. There are similarities as well as differences between applying fusion to propulsion and to terrestrial electrical power generation. The similarities are the underlying plasma and fusion physics, the enabling component technologies, the computational and the diagnostics capabilities. These physics and

A stabilized headless measles virus attachment protein stalk efficiently triggers membrane fusion.

PubMed

Brindley, Melinda A; Suter, Rolf; Schestak, Isabel; Kiss, Gabriella; Wright, Elizabeth R; Plemper, Richard K

2013-11-01

Paramyxovirus attachment and fusion (F) envelope glycoprotein complexes mediate membrane fusion required for viral entry. The measles virus (MeV) attachment (H) protein stalk domain is thought to directly engage F for fusion promotion. However, past attempts to generate truncated, fusion-triggering-competent H-stem constructs remained fruitless. In this study, we addressed the problem by testing the hypothesis that truncated MeV H stalks may require stabilizing oligomerization tags to maintain intracellular transport competence and F-triggering activity. We engineered H-stems of different lengths with added 4-helix bundle tetramerization domains and demonstrate restored cell surface expression, efficient interaction with F, and fusion promotion activity of these constructs. The stability of the 4-helix bundle tags and the relative orientations of the helical wheels of H-stems and oligomerization tags govern the kinetics of fusion promotion, revealing a balance between H stalk conformational stability and F-triggering activity. Recombinant MeV particles expressing a bioactive H-stem construct in the place of full-length H are viable, albeit severely growth impaired. Overall, we demonstrate that the MeV H stalk represents the effector domain for MeV F triggering. Fusion promotion appears linked to the conformational flexibility of the stalk, which must be tightly regulated in viral particles to ensure efficient virus entry. While the pathways toward assembly of functional fusion complexes may differ among diverse members of the paramyxovirus family, central elements of the triggering machinery emerge as highly conserved.

A High-Density, High-Efficiency, Isolated On-Board Vehicle Battery Charger Utilizing Silicon Carbide Power Devices

DOE Office of Scientific and Technical Information (OSTI.GOV)

Whitaker, B; Barkley, A; Cole, Z

2014-05-01

This paper presents an isolated on-board vehicular battery charger that utilizes silicon carbide (SiC) power devices to achieve high density and high efficiency for application in electric vehicles (EVs) and plug-in hybrid EVs (PHEVs). The proposed level 2 charger has a two-stage architecture where the first stage is a bridgeless boost ac-dc converter and the second stage is a phase-shifted full-bridge isolated dc-dc converter. The operation of both topologies is presented and the specific advantages gained through the use of SiC power devices are discussed. The design of power stage components, the packaging of the multichip power module, and themore » system-level packaging is presented with a primary focus on system density and a secondary focus on system efficiency. In this work, a hardware prototype is developed and a peak system efficiency of 95% is measured while operating both power stages with a switching frequency of 200 kHz. A maximum output power of 6.1 kW results in a volumetric power density of 5.0 kW/L and a gravimetric power density of 3.8 kW/kg when considering the volume and mass of the system including a case.« less

The High Field Path to Practical Fusion Energy

NASA Astrophysics Data System (ADS)

Mumgaard, Robert; Whyte, D.; Greenwald, M.; Hartwig, Z.; Brunner, D.; Sorbom, B.; Marmar, E.; Minervini, J.; Bonoli, P.; Irby, J.; Labombard, B.; Terry, J.; Vieira, R.; Wukitch, S.

2017-10-01

We propose a faster, lower cost development path for fusion energy enabled by high temperature superconductors, devices at high magnetic field, innovative technologies and modern approaches to technology development. Timeliness, scale, and economic-viability are the drivers for fusion energy to combat climate change and aid economic development. The opportunities provided by high-temperature superconductors, innovative engineering and physics, and new organizational structures identified over the last few years open new possibilities for realizing practical fusion energy that could meet mid-century de-carbonization needs. We discuss re-factoring the fusion energy development path with an emphasis on concrete risk retirement strategies utilizing a modular approach based on the high-field tokamak that leverages the broader tokamak physics understanding of confinement, stability, and operational limits. Elements of this plan include development of high-temperature superconductor magnets, simplified immersion blankets, advanced long-leg divertors, a compact divertor test tokamak, efficient current drive, modular construction, and demountable magnet joints. An R&D plan culminating in the construction of an integrated pilot plant and test facility modeled on the ARC concept is presented.

Editorially Speaking - Fusion Power: Reasons for Higher Priority

ERIC Educational Resources Information Center

Lippincott, William T.

1973-01-01

Discusses current research trends in the use of laser-fusion technology in combustion chambers to eradicate energy shortages. Indicates that fusion power could be made available at a relatively low expense. (CC)

NASA satellite communications application research. Phase 2: Efficient high power, solid state amplifier for EFH communications

NASA Technical Reports Server (NTRS)

Benet, James

1993-01-01

The final report describes the work performed from 9 Jun. 1992 to 31 Jul. 1993 on the NASA Satellite Communications Application Research (SCAR) Phase 2 program, Efficient High Power, Solid State Amplifier for EHF Communications. The purpose of the program was to demonstrate the feasibility of high-efficiency, high-power, EHF solid state amplifiers that are smaller, lighter, more efficient, and less costly than existing traveling wave tube (TWT) amplifiers by combining the output power from up to several hundred solid state amplifiers using a unique orthomode spatial power combiner (OSPC).

‘Squeezing’ near-field thermal emission for ultra-efficient high-power thermophotovoltaic conversion

PubMed Central

Karalis, Aristeidis; Joannopoulos, J. D.

2016-01-01

We numerically demonstrate near-field planar ThermoPhotoVoltaic systems with very high efficiency and output power, at large vacuum gaps. Example performances include: at 1200 °K emitter temperature, output power density 2 W/cm2 with ~47% efficiency at 300 nm vacuum gap; at 2100 °K, 24 W/cm2 with ~57% efficiency at 200 nm gap; and, at 3000 °K, 115 W/cm2 with ~61% efficiency at 140 nm gap. Key to this striking performance is a novel photonic design forcing the emitter and cell single modes to cros resonantly couple and impedance-match just above the semiconductor bandgap, creating there a ‘squeezed’ narrowband near-field emission spectrum. Specifically, we employ surface-plasmon-polariton thermal emitters and silver-backed semiconductor-thin-film photovoltaic cells. The emitter planar plasmonic nature allows for high-power and stable high-temperature operation. Our simulations include modeling of free-carrier absorption in both cell electrodes and temperature dependence of the emitter properties. At high temperatures, the efficiency enhancement via resonant mode cross-coupling and matching can be extended to even higher power, by appropriately patterning the silver back electrode to enforce also an absorber effective surface-plasmon-polariton mode. Our proposed designs can therefore lead the way for mass-producible and low-cost ThermoPhotoVoltaic micro-generators and solar cells. PMID:27363522

LIFE: a sustainable solution for developing safe, clean fusion power.

PubMed

Reyes, Susana; Dunne, Mike; Kramer, Kevin; Anklam, Tom; Havstad, Mark; Mazuecos, Antonio Lafuente; Miles, Robin; Martinez-Frias, Joel; Deri, Bob

2013-06-01

The National Ignition Facility (NIF) at the Lawrence Livermore National Laboratory (LLNL) in California is currently in operation with the goal to demonstrate fusion energy gain for the first time in the laboratory-also referred to as "ignition." Based on these demonstration experiments, the Laser Inertial Fusion Energy (LIFE) power plant is being designed at LLNL in partnership with other institutions with the goal to deliver baseload electricity from safe, secure, sustainable fusion power in a time scale that is consistent with the energy market needs. For this purpose, the LIFE design takes advantage of recent advances in diode-pumped, solid-state laser technology and adopts the paradigm of Line Replaceable Units used on the NIF to provide high levels of availability and maintainability and mitigate the need for advanced materials development. The LIFE market entry plant will demonstrate the feasibility of a closed fusion fuel cycle, including tritium breeding, extraction, processing, refueling, accountability, and safety, in a steady-state power-producing device. While many fusion plant designs require large quantities of tritium for startup and operations, a range of design choices made for the LIFE fuel cycle act to reduce the in-process tritium inventory. This paper presents an overview of the delivery plan and the preconceptual design of the LIFE facility with emphasis on the key safety design principles being adopted. In order to illustrate the favorable safety characteristics of the LIFE design, some initial accident analysis results are presented that indicate potential for a more attractive licensing regime than that of current fission reactors.

High Efficiency, Low Power-Consumption DFB Quantum Cascade Lasers Without Lateral Regrowth

NASA Astrophysics Data System (ADS)

Jia, Zhi-Wei; Wang, Li-Jun; Zhang, Jin-Chuan; Liu, Feng-Qi; Zhou, Yu-Hong; Wang, Dong-Bo; Jia, Xue-Feng; Zhuo, Ning; Liu, Jun-Qi; Zhai, Shen-Qiang; Wang, Zhan-Guo

2017-04-01

Very low power-consumption distributed feedback (DFB) quantum cascade lasers (QCLs) at the wavelength around 4.9 μm were fabricated by conventional process without lateral regrowth of InP:Fe or using sidewall grating. Benefitted from the optimized materials and low waveguide loss, very low threshold current density of 0.5 kA/cm2 was obtained for a device with cavity length of 2 mm. Combined with the partial-high-reflection coating, the 1-mm-long DFB QCL achieved low power-consumption continuous wave (CW) operation up to 105 °C. The CW threshold power-consumptions were 0.72 and 0.78 W at 15 and 25 °C, respectively. The maximum CW output power was over 110 mW at 15 °C and still more than 35 mW at 105 °C. At 15 °C, wall-plug efficiency of 5.5% and slope efficiency of 1.8 W/A were deduced, which were very high for low power-consumption DFB QCLs.

Evolution of Automotive Chopper Circuits Towards Ultra High Efficiency and Power Density

NASA Astrophysics Data System (ADS)

Pavlovsky, Martin; Tsuruta, Yukinori; Kawamura, Atsuo

Automotive industry is considered to be one of the main contributors to environmental pollution and global warming. Therefore, many car manufacturers are in near future planning to introduce hybrid electric vehicles (HEV), fuel cell electric vehicles (FCEV) and pure electric vehicles (EV) to make our cars more environmentally friendly. These new vehicles require highly efficient and small power converters. In recent years, considerable improvements were made in designing such converters. In this paper, an approach based on so called Snubber Assisted Zero Voltage and Zero Current Switching topology otherwise also known as SAZZ is presented. This topology has evolved to be one of the leaders in the field of highly efficient converters with high power densities. Evolution and main features of this topology are briefly discussed. Capabilities of the topology are demonstrated on two case study prototypes based on different design approaches. The prototypes are designed to be fully bi-directional for peak power output of 30kW. Both designs reached efficiencies close to 99% in wide load range. Power densities over 40kW/litre are attainable in the same time. Combination of MOSFET technology and SAZZ topology is shown to be very beneficial to converters designed for EV applications.

Research on the technical requirements standards of high efficiency precipitator in power industries for assessment

NASA Astrophysics Data System (ADS)

Jin, Huang; Ling, Lin; Jun, Guo; Jianguo, Li; Yongzhong, Wang

2017-11-01

Facing the increasingly severe situation of air pollution, China are now positively promoting the evaluation of high efficiency air pollution control equipments and the research of the relative national standards. This paper showed the significance and the effect of formulating the technical requirements of high efficiency precipitator equipments for assessment national standards in power industries as well as the research thoughts and principle of these standards. It introduce the qualitative and quantitative evaluation requirements of high efficiency precipitators using in power industries and the core technical content such as testing, calculating, evaluation methods and so on. The implementation of a series of national standards is in order to lead and promote the production and application of high efficiency precipitator equipments in the field of the prevention of air pollution in national power industries.

Introduction to Nuclear Fusion Power and the Design of Fusion Reactors. An Issue-Oriented Module.

ERIC Educational Resources Information Center

Fillo, J. A.

This three-part module focuses on the principles of nuclear fusion and on the likely nature and components of a controlled-fusion power reactor. The physical conditions for a net energy release from fusion and two approaches (magnetic and inertial confinement) which are being developed to achieve this goal are described. Safety issues associated…

High Power LaB6 Plasma Source Performance for the Lockheed Martin Compact Fusion Reactor Experiment

NASA Astrophysics Data System (ADS)

Heinrich, Jonathon

2016-10-01

Lockheed Martin's Compact Fusion Reactor (CFR) concept is a linear encapsulated ring cusp. Due to the complex field geometry, plasma injection into the device requires careful consideration. A high power thermionic plasma source (>0.25MW; >10A/cm2) has been developed with consideration to phase space for optimal coupling. We present the performance of the plasma source, comparison with alternative plasma sources, and plasma coupling with the CFR field configuration. ©2016 Lockheed Martin Corporation. All Rights Reserved.

High Efficiency, Low Power-Consumption DFB Quantum Cascade Lasers Without Lateral Regrowth.

PubMed

Jia, Zhi-Wei; Wang, Li-Jun; Zhang, Jin-Chuan; Liu, Feng-Qi; Zhou, Yu-Hong; Wang, Dong-Bo; Jia, Xue-Feng; Zhuo, Ning; Liu, Jun-Qi; Zhai, Shen-Qiang; Wang, Zhan-Guo

2017-12-01

Very low power-consumption distributed feedback (DFB) quantum cascade lasers (QCLs) at the wavelength around 4.9 μm were fabricated by conventional process without lateral regrowth of InP:Fe or using sidewall grating. Benefitted from the optimized materials and low waveguide loss, very low threshold current density of 0.5 kA/cm 2 was obtained for a device with cavity length of 2 mm. Combined with the partial-high-reflection coating, the 1-mm-long DFB QCL achieved low power-consumption continuous wave (CW) operation up to 105 °C. The CW threshold power-consumptions were 0.72 and 0.78 W at 15 and 25 °C, respectively. The maximum CW output power was over 110 mW at 15 °C and still more than 35 mW at 105 °C. At 15 °C, wall-plug efficiency of 5.5% and slope efficiency of 1.8 W/A were deduced, which were very high for low power-consumption DFB QCLs.

Intense fusion neutron sources

NASA Astrophysics Data System (ADS)

Kuteev, B. V.; Goncharov, P. R.; Sergeev, V. Yu.; Khripunov, V. I.

2010-04-01

The review describes physical principles underlying efficient production of free neutrons, up-to-date possibilities and prospects of creating fission and fusion neutron sources with intensities of 1015-1021 neutrons/s, and schemes of production and application of neutrons in fusion-fission hybrid systems. The physical processes and parameters of high-temperature plasmas are considered at which optimal conditions for producing the largest number of fusion neutrons in systems with magnetic and inertial plasma confinement are achieved. The proposed plasma methods for neutron production are compared with other methods based on fusion reactions in nonplasma media, fission reactions, spallation, and muon catalysis. At present, intense neutron fluxes are mainly used in nanotechnology, biotechnology, material science, and military and fundamental research. In the near future (10-20 years), it will be possible to apply high-power neutron sources in fusion-fission hybrid systems for producing hydrogen, electric power, and technological heat, as well as for manufacturing synthetic nuclear fuel and closing the nuclear fuel cycle. Neutron sources with intensities approaching 1020 neutrons/s may radically change the structure of power industry and considerably influence the fundamental and applied science and innovation technologies. Along with utilizing the energy produced in fusion reactions, the achievement of such high neutron intensities may stimulate wide application of subcritical fast nuclear reactors controlled by neutron sources. Superpower neutron sources will allow one to solve many problems of neutron diagnostics, monitor nano-and biological objects, and carry out radiation testing and modification of volumetric properties of materials at the industrial level. Such sources will considerably (up to 100 times) improve the accuracy of neutron physics experiments and will provide a better understanding of the structure of matter, including that of the neutron itself.

High-Power, High-Efficiency Ka-Band Space Traveling-Wave Tube

NASA Technical Reports Server (NTRS)

Krawczyk, Richard; Wilson, Jeffrey; Simons, Rainee; Williams, Wallace; Bhasin, Kul; Robbins, Neal; Dibb, Daniel; Menninger, William; Zhai, Xiaoling; Benton, Robert;

Improvement of force factor of magnetostrictive vibration power generator for high efficiency

NASA Astrophysics Data System (ADS)

Kita, Shota; Ueno, Toshiyuki; Yamada, Sotoshi

2015-05-01

We develop high power magnetostrictive vibration power generator for battery-free wireless electronics. The generator is based on a cantilever of parallel beam structure consisting of coil-wound Galfenol and stainless plates with permanent magnet for bias. Oscillating force exerted on the tip bends the cantilever in vibration yields stress variation of Galfenol plate, which causes flux variation and generates voltage on coil due to the law of induction. This generator has advantages over conventional, such as piezoelectric or moving magnet types, in the point of high efficiency, highly robust, and low electrical impedance. Our concern is the improvement of energy conversion efficiency dependent on the dimension. Especially, force factor, the conversion ratio of the electromotive force (voltage) on the tip velocity in vibration, has an important role in energy conversion process. First, the theoretical value of the force factor is formulated and then the validity was verified by experiments, where we compare four types of prototype with parameters of the dimension using 7.0 × 1.5 × 50 mm beams of Galfenol with 1606-turn wound coil. In addition, the energy conversion efficiency of the prototypes depending on load resistance was measured. The most efficient prototype exhibits the maximum instantaneous power of 0.73 W and energy of 4.7 mJ at a free vibration of frequency of 202 Hz in the case of applied force is 25 N. Further, it was found that energy conversion efficiency depends not only on the force factor but also on the damping (mechanical loss) of the vibration.

Impact of Energy Gain and Subsystem Characteristics on Fusion Propulsion Performance

NASA Technical Reports Server (NTRS)

Chakrabarti, S.; Schmidt, G. R.

2001-01-01

Rapid transport of large payloads and human crews throughout the solar system requires propulsion systems having very high specific impulse (I(sub sp) > 10(exp 4) to 10(exp 5) s). It also calls for systems with extremely low mass-power ratios (alpha < 10(exp -1) kg/kW). Such low alpha are beyond the reach of conventional power-limited propulsion, but may be attainable with fusion and other nuclear concepts that produce energy within the propellant. The magnitude of energy gain must be large enough to sustain the nuclear process while still providing a high jet power relative to the massive energy-intensive subsystems associated with these concepts. This paper evaluates the impact of energy gain and subsystem characteristics on alpha. Central to the analysis are general parameters that embody the essential features of any 'gain-limited' propulsion power balance. Results show that the gains required to achieve alpha = 10(exp -1) kg/kW with foreseeable technology range from approximately 100 to over 2000, which is three to five orders of magnitude greater than current fusion state of the arL Sensitivity analyses point to the parameters exerting the most influence for either: (1) lowering a and improving mission performance or (2) relaxing gain requirements and reducing demands on the fusion process. The greatest impact comes from reducing mass and increasing efficiency of the thruster and subsystems downstream of the fusion process. High relative gain, through enhanced fusion processes or more efficient drivers and processors, is also desirable. There is a benefit in improving driver and subsystem characteristics upstream of the fusion process, but it diminishes at relative gains > 100.

Fusion energy for space: Feasibility demonstration. A proposal to NASA

NASA Technical Reports Server (NTRS)

Schulze, Norman R.

1992-01-01

This proposed program is to initiate a space flight research and development program to develop fusion energy for the space applications of direct space propulsion and direct space power, that is, a Space Fusion Energy (SFE) program. 'Direct propulsion' refers to the use of plasma energy directly for thrust without requiring other energy conversion systems. Further, to provide space missions with large electrical power, 'direct space power' is proposed whereby the direct conversion of charged particles into electricity is used, thereby avoiding thermal conversion system losses. The energy release from nuclear fusion reactions makes these highly efficient, high power space systems possible. The program as presented conducts in an orderly, hierarchical manner the necessary planning, analyses, and testing to demonstrate the practical use of fusion energy for space. There is nothing discussed that is known to be theoretically impossible. Validation of the engineering principles is sought in this program which uses a cost-benefit approach. Upon successful program completion, space will become more accessible and space missions more safely conducted. The country will have taken a giant step toward the commercialization of space. The mission enabling capability provided by fusion energy is well beyond mission planners' current dreams.

Safety and Environment aspects of Tokamak- type Fusion Power Reactor- An Overview

NASA Astrophysics Data System (ADS)

Doshi, Bharat; Reddy, D. Chenna

2017-04-01

Naturally occurring thermonuclear fusion reaction (of light atoms to form a heavier nucleus) in the sun and every star in the universe, releases incredible amounts of energy. Demonstrating the controlled and sustained reaction of deuterium-tritium plasma should enable the development of fusion as an energy source here on Earth. The promising fusion power reactors could be operated on the deuterium-tritium fuel cycle with fuel self-sufficiency. The potential impact of fusion power on the environment and the possible risks associated with operating large-scale fusion power plants is being studied by different countries. The results show that fusion can be a very safe and sustainable energy source. A fusion power plant possesses not only intrinsic advantages with respect to safety compared to other sources of energy, but also a negligible long term impact on the environment provided certain precautions are taken in its design. One of the important considerations is in the selection of low activation structural materials for reactor vessel. Selection of the materials for first wall and breeding blanket components is also important from safety issues. It is possible to fully benefit from the advantages of fusion energy if safety and environmental concerns are taken into account when considering the conceptual studies of a reactor design. The significant safety hazards are due to the tritium inventory and energetic neutron fluence induced activity in the reactor vessel, first wall components, blanket system etc. The potential of release of radioactivity under operational and accident conditions needs attention while designing the fusion reactor. Appropriate safety analysis for the quantification of the risk shall be done following different methods such as FFMEA (Functional Failure Modes and Effects Analysis) and HAZOP (Hazards and operability). Level of safety and safety classification such as nuclear safety and non-nuclear safety is very important for the FPR (Fusion

High Efficiency Thermoelectric Radioisotope Power Systems

NASA Technical Reports Server (NTRS)

El-Genk, Mohamed; Saber, Hamed; Caillat, Thierry

2004-01-01

The work performed and whose results presented in this report is a joint effort between the University of New Mexico s Institute for Space and Nuclear Power Studies (ISNPS) and the Jet Propulsion Laboratory (JPL), California Institute of Technology. In addition to the development, design, and fabrication of skutterudites and skutterudites-based segmented unicouples this effort included conducting performance tests of these unicouples for hundreds of hours to verify theoretical predictions of the conversion efficiency. The performance predictions of these unicouples are obtained using 1-D and 3-D models developed for that purpose and for estimating the actual performance and side heat losses in the tests conducted at ISNPS. In addition to the performance tests, the development of the 1-D and 3-D models and the development of Advanced Radioisotope Power systems for Beginning-Of-Life (BOM) power of 108 We are carried out at ISNPS. The materials synthesis and fabrication of the unicouples are carried out at JPL. The research conducted at ISNPS is documented in chapters 2-5 and that conducted at JP, in documented in chapter 5. An important consideration in the design and optimization of segmented thermoelectric unicouples (STUs) is determining the relative lengths, cross-section areas, and the interfacial temperatures of the segments of the different materials in the n- and p-legs. These variables are determined using a genetic algorithm (GA) in conjunction with one-dimensional analytical model of STUs that is developed in chapter 2. Results indicated that when optimized for maximum conversion efficiency, the interfacial temperatures between various segments in a STU are close to those at the intersections of the Figure-Of-Merit (FOM), ZT, curves of the thermoelectric materials of the adjacent segments. When optimizing the STUs for maximum electrical power density, however, the interfacial temperatures are different from those at the intersections of the ZT curves, but

High-power and highly efficient diode-cladding-pumped Ho3+-doped silica fiber lasers.

PubMed

Jackson, Stuart D; Bugge, Frank; Erbert, Götz

2007-11-15

We demonstrate high-power operation from a singly Ho3+-doped silica fiber laser that is cladding pumped directly with diode lasers operating at 1150 nm. Internal slope efficiencies approaching the Stokes limit were produced, and the maximum output power was 2.2W. This result was achieved using a low Ho3+-ion concentration and La3+-ion codoping, which together limit the transfer of energy between excited Ho3+ ions.

High energy efficiency and high power density proton exchange membrane fuel cells: Electrode kinetics and mass transport

NASA Technical Reports Server (NTRS)

Srinivasan, Supramaniam; Velev, Omourtag A.; Parthasathy, Arvind; Manko, David J.; Appleby, A. John

1991-01-01

The development of proton exchange membrane (PEM) fuel cell power plants with high energy efficiencies and high power densities is gaining momentum because of the vital need of such high levels of performance for extraterrestrial (space, underwater) and terrestrial (power source for electric vehicles) applications. Since 1987, considerable progress has been made in achieving energy efficiencies of about 60 percent at a current density of 200 mA/sq cm and high power densities (greater than 1 W/sq cm) in PEM fuel cells with high (4 mg/sq cm) or low (0.4 mg/sq cm) platinum loadings in electrodes. The following areas are discussed: (1) methods to obtain these high levels of performance with low Pt loading electrodes - by proton conductor impregnation into electrodes, localization of Pt near front surface; (2) a novel microelectrode technique which yields electrode kinetic parameters for oxygen reduction and mass transport parameters; (3) demonstration of lack of water transport from anode to cathode; (4) modeling analysis of PEM fuel cell for comparison with experimental results and predicting further improvements in performance; and (5) recommendations of needed research and development for achieving the above goals.

Commercial objectives, technology transfer, and systems analysis for fusion power development

NASA Astrophysics Data System (ADS)

Dean, Stephen O.

1988-03-01

Fusion is an essentially inexhaustible source of energy that has the potential for economically attractive commercial applications with excellent safety and environmental characteristics. The primary focus for the fusion-energy development program is the generation of centralstation electricity. Fusion has the potential, however, for many other applications. The fact that a large fraction of the energy released in a DT fusion reaction is carried by high-energy neutrons suggests potentially unique applications. These include breeding of fissile fuels, production of hydrogen and other chemical products, transmutation or “burning” of various nuclear or chemical wastes, radiation processing of materials, production of radioisotopes, food preservation, medical diagnosis and medical treatment, and space power and space propulsion. In addition, fusion R&D will lead to new products and new markets. Each fusion application must meet certain standards of economic and safety and environmental attractiveness. For this reason, economics on the one hand, and safety and environment and licensing on the other hand, are the two primary criteria for setting long-range commercial fusion objectives. A major function of systems analysis is to evaluate the potential of fusion against these objectives and to help guide the fusion R&D program toward practical applications. The transfer of fusion technology and skills from the national laboratories and universities to industry is the key to achieving the long-range objective of commercial fusion applications.

High Speed and High Functional Inverter Power Supplies for Plasma Generation and Control, and their Performance

NASA Astrophysics Data System (ADS)

Uesugi, Yoshihiko; Razzak, Mohammad A.; Kondo, Kenji; Kikuchi, Yusuke; Takamura, Shuichi; Imai, Takahiro; Toyoda, Mitsuhiro

The Rapid development of high power and high speed semiconductor switching devices has led to their various applications in related plasma fields. Especially, a high speed inverter power supply can be used as an RF power source instead of conventional linear amplifiers and a power supply to control the magnetic field in a fusion plasma device. In this paper, RF thermal plasma production and plasma heating experiments are described emphasis placed on using a static induction transistor inverter at a frequency range between 200 kHz and 2.5 MHz as an RF power supply. Efficient thermal plasma production is achieved experimentally by using a flexible and easily operated high power semiconductor inverter power supply. Insulated gate bipolar transistor (IGBT) inverter power supplies driven by a high speed digital signal processor are applied as tokamak joule coil and vertical coil power supplies to control plasma current waveform and plasma equilibrium. Output characteristics, such as the arbitrary bipolar waveform generation of a pulse width modulation (PWM) inverter using digital signal processor (DSP) can be successfully applied to tokamak power supplies for flexible plasma current operation and fast position control of a small tokamak.

X-ray conversion efficiency of high-Z hohlraum wall materials for indirect drive ignition

NASA Astrophysics Data System (ADS)

Dewald, E. L.; Rosen, M.; Glenzer, S. H.; Suter, L. J.; Girard, F.; Jadaud, J. P.; Schein, J.; Constantin, C.; Wagon, F.; Huser, G.; Neumayer, P.; Landen, O. L.

2008-07-01

The conversion efficiency of 351nm laser light to soft x rays (0.1-5keV) was measured for Au, U, and high Z mixture "cocktails" used as hohlraum wall materials in indirect drive fusion experiments. For the spherical targets in a direct drive geometry, flattop laser pulses and laser smoothing with phase plates are employed to achieve constant and uniform laser intensities of 1014 and 1015W/cm2 over the target surface that are relevant for the future ignition experiments at the National Ignition Facility [G. H. Miller, E. I. Moses, and C. R. Wuest, Nucl. Fusion 44, 228 (2004)]. The absolute time and spectrally resolved radiation flux is measured with a multichannel soft x-ray power diagnostic. The conversion efficiency is then calculated by dividing the measured x-ray power by the incident laser power from which the measured laser backscattering losses are subtracted. After ˜0.5ns, the time resolved x-ray conversion efficiency reaches a slowly increasing plateau of 95% at 1014W/cm2 laser intensity and of 80% at 1015W/cm2. The M-band flux (2-5keV) is negligible at 1014W/cm2 reaching ˜1% of the total x-ray flux for all target materials. In contrast, the M-band flux is significant and depends on the target material at 1015W/cm2 laser intensity, reaching values between 10% of the total flux for U and 27% for Au. LASNEX simulations [G. B. Zimmerman and W. L. Kruer, Comm. Plasma Phys. Contr. Fusion 2, 51 (1975)] show good agreement in conversion efficiency and radiated spectra with data when using XSN atomic physics model and a flux limiter of 0.15, but they underestimate the generated M-band flux.

Design of an Ultra-High Efficiency GaN High-Power Amplifier for SAR Remote Sensing

NASA Technical Reports Server (NTRS)

Thrivikraman, Tushar; Hoffman, James

2013-01-01

This work describes the development of a high-power amplifier for use with a remote sensing SAR system. The amplifier is intended to meet the requirements for the Sweep-SAR technique for use in the proposed DESDynI SAR instrument. In order to optimize the amplifier design, active load-pull technique is employed to provide harmonic tuning to provide efficiency improvements. In addition, some of the techniques to overcome the challenges of load-pulling high power devices are presented. The design amplifier was measured to have 49 dBm of output power with 75% PAE, which is suitable to meet the proposed system requirements.

Efficient replication of a paramyxovirus independent of full zippering of the fusion protein six-helix bundle domain

PubMed Central

Brindley, Melinda A.; Plattet, Philippe; Plemper, Richard Karl

2014-01-01

Enveloped viruses such as HIV and members of the paramyxovirus family use metastable, proteinaceous fusion machineries to merge the viral envelope with cellular membranes for infection. A hallmark of the fusogenic glycoproteins of these pathogens is refolding into a thermodynamically highly stable fusion core structure composed of six antiparallel α-helices, and this structure is considered instrumental for pore opening and/or enlargement. Using a paramyxovirus fusion (F) protein, we tested this paradigm by engineering covalently restricted F proteins that are predicted to be unable to close the six-helix bundle core structure fully. Several candidate bonds formed efficiently, resulting in F trimers and higher-order complexes containing covalently linked dimers. The engineered F complexes were incorporated into recombinant virions efficiently and were capable of refolding into a postfusion conformation without temporary or permanent disruption of the disulfide bonds. They efficiently formed fusion pores based on virus replication and quantitative cell-to-cell and virus-to-cell fusion assays. Complementation of these F mutants with a monomeric, fusion-inactive F variant enriched the F oligomers for heterotrimers containing a single disulfide bond, without affecting fusion complementation profiles compared with standard F protein. Our demonstration that complete closure of the fusion core does not drive paramyxovirus entry may aid the design of strategies for inhibiting virus entry. PMID:25157143

Efficient replication of a paramyxovirus independent of full zippering of the fusion protein six-helix bundle domain.

PubMed

Brindley, Melinda A; Plattet, Philippe; Plemper, Richard Karl

2014-09-09

Enveloped viruses such as HIV and members of the paramyxovirus family use metastable, proteinaceous fusion machineries to merge the viral envelope with cellular membranes for infection. A hallmark of the fusogenic glycoproteins of these pathogens is refolding into a thermodynamically highly stable fusion core structure composed of six antiparallel α-helices, and this structure is considered instrumental for pore opening and/or enlargement. Using a paramyxovirus fusion (F) protein, we tested this paradigm by engineering covalently restricted F proteins that are predicted to be unable to close the six-helix bundle core structure fully. Several candidate bonds formed efficiently, resulting in F trimers and higher-order complexes containing covalently linked dimers. The engineered F complexes were incorporated into recombinant virions efficiently and were capable of refolding into a postfusion conformation without temporary or permanent disruption of the disulfide bonds. They efficiently formed fusion pores based on virus replication and quantitative cell-to-cell and virus-to-cell fusion assays. Complementation of these F mutants with a monomeric, fusion-inactive F variant enriched the F oligomers for heterotrimers containing a single disulfide bond, without affecting fusion complementation profiles compared with standard F protein. Our demonstration that complete closure of the fusion core does not drive paramyxovirus entry may aid the design of strategies for inhibiting virus entry.

Power-Efficient, High-Current-Density, Long-Life Thermionic Cathode Developed for Microwave Amplifier Applications

NASA Technical Reports Server (NTRS)

Wintucky, Edwin G.

2002-01-01

A power-efficient, miniature, easily manufactured, reservoir-type barium-dispenser thermionic cathode has been developed that offers the significant advantages of simultaneous high electron-emission current density (>2 A/sq cm) and very long life (>100,000 hr of continuous operation) when compared with the commonly used impregnated-type barium-dispenser cathodes. Important applications of this cathode are a wide variety of microwave and millimeter-wave vacuum electronic devices, where high output power and reliability (long life) are essential. We also expect it to enable the practical development of higher purveyance electron guns for lower voltage and more reliable device operation. The low cathode heater power and reduced size and mass are expected to be particularly beneficial in traveling-wave-tube amplifiers (TWTA's) for space communications, where future NASA mission requirements include smaller onboard spacecraft systems, higher data transmission rates (high frequency and output power) and greater electrical efficiency.

Ultra High Power and Efficiency Space Traveling-Wave Tube Amplifier Power Combiner with Reduced Size and Mass for NASA Missions

NASA Technical Reports Server (NTRS)

Simons, Rainee N.; Wintucky, Edwin G.; Wilson, Jeffrey D.; Force, Dale A.

2009-01-01

In the 2008 International Microwave Symposium (IMS) Digest version of our paper, recent advances in high power and efficiency space traveling-wave tube amplifiers (TWTAs) for NASA s space-to-Earth communications are presented. The RF power and efficiency of a new K-Band amplifier are 40 W and 50 percent and that of a new Ka-Band amplifier are 200 W and 60 percent. An important figure-of-merit, which is defined as the ratio of the RF power output to the mass (W/kg) of a TWT, has improved by a factor of ten over the previous generation Ka-Band devices. In this extended paper, a high power, high efficiency Ka-band combiner for multiple TWTs, based on a novel hybrid magic-T waveguide circuit design, is presented. The measured combiner efficiency is as high as 90 percent. In addition, at the design frequency of 32.05 GHz, error-free uncoded BPSK/QPSK data transmission at 8 megabits per second (Mbps), which is typical for deep space communications is demonstrated. Furthermore, QPSK data transmission at 622 Mbps is demonstrated with a low bit error rate of 2.4x10(exp -8), which exceeds the deep space state-of-the-art data rate transmission capability by more than two orders of magnitude. A potential application of the TWT combiner is in deep space communication systems for planetary exploration requiring transmitter power on the order of a kilowatt or higher.

Propagation of nuclear data uncertainties for fusion power measurements

NASA Astrophysics Data System (ADS)

Sjöstrand, Henrik; Conroy, Sean; Helgesson, Petter; Hernandez, Solis Augusto; Koning, Arjan; Pomp, Stephan; Rochman, Dimitri

2017-09-01

Neutron measurements using neutron activation systems are an essential part of the diagnostic system at large fusion machines such as JET and ITER. Nuclear data is used to infer the neutron yield. Consequently, high-quality nuclear data is essential for the proper determination of the neutron yield and fusion power. However, uncertainties due to nuclear data are not fully taken into account in uncertainty analysis for neutron yield calibrations using activation foils. This paper investigates the neutron yield uncertainty due to nuclear data using the so-called Total Monte Carlo Method. The work is performed using a detailed MCNP model of the JET fusion machine; the uncertainties due to the cross-sections and angular distributions in JET structural materials, as well as the activation cross-sections in the activation foils, are analysed. It is found that a significant contribution to the neutron yield uncertainty can come from uncertainties in the nuclear data.

High Efficiency and Low Cost Thermal Energy Storage System

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sienicki, James J.; Lv, Qiuping; Moisseytsev, Anton

BgtL, LLC (BgtL) is focused on developing and commercializing its proprietary compact technology for processes in the energy sector. One such application is a compact high efficiency Thermal Energy Storage (TES) system that utilizes the heat of fusion through phase change between solid and liquid to store and release energy at high temperatures and incorporate state-of-the-art insulation to minimize heat dissipation. BgtL’s TES system would greatly improve the economics of existing nuclear and coal-fired power plants by allowing the power plant to store energy when power prices are low and sell power into the grid when prices are high. Comparedmore » to existing battery storage technology, BgtL’s novel thermal energy storage solution can be significantly less costly to acquire and maintain, does not have any waste or environmental emissions, and does not deteriorate over time; it can keep constant efficiency and operates cleanly and safely. BgtL’s engineers are experienced in this field and are able to design and engineer such a system to a specific power plant’s requirements. BgtL also has a strong manufacturing partner to fabricate the system such that it qualifies for an ASME code stamp. BgtL’s vision is to be the leading provider of compact systems for various applications including energy storage. BgtL requests that all technical information about the TES designs be protected as proprietary information. To honor that request, only non-proprietay summaries are included in this report.« less

Broadband linearisation of high-efficiency power amplifiers

NASA Technical Reports Server (NTRS)

Kenington, Peter B.; Parsons, Kieran J.; Bennett, David W.

1993-01-01

A feedforward-based amplifier linearization technique is presented which is capable of yielding significant improvements in both linearity and power efficiency over conventional amplifier classes (e.g. class-A or class-AB). Theoretical and practical results are presented showing that class-C stages may be used for both the main and error amplifiers yielding practical efficiencies well in excess of 30 percent, with theoretical efficiencies of much greater than 40 percent being possible. The levels of linearity which may be achieved are required for most satellite systems, however if greater linearity is required, the technique may be used in addition to conventional pre-distortion techniques.

Efficiency limits of laser power converters for optical power transfer applications

NASA Astrophysics Data System (ADS)

Mukherjee, J.; Jarvis, S.; Perren, M.; Sweeney, S. J.

2013-07-01

We have developed III-V-based high-efficiency laser power converters (LPCs), optimized specifically for converting monochromatic laser radiation at the eye-safe wavelength of 1.55 µm into electrical power. The applications of these photovoltaic cells include high-efficiency space-based and terrestrial laser power transfer and subsequent conversion to electrical power. In addition, these cells also find use in fibre-optic power delivery, remote powering of subcutaneous equipment and several other optical power delivery applications. The LPC design is based on lattice-matched InGaAsP/InP and incorporates elements for photon-recycling and contact design for efficient carrier extraction. Here we compare results from electro-optical design simulations with experimental results from prototype devices studied both in the lab and in field tests. We analyse wavelength and temperature dependence of the LPC characteristics. An experimental conversion efficiency of 44.6% [±1%] is obtained from the prototype devices under monochromatic illumination at 1.55 µm (illumination power density of 1 kW m-2) at room temperature. Further design optimization of our LPC is expected to scale the efficiency beyond 50% at 1 kW m-2.

Beyond ITER: neutral beams for a demonstration fusion reactor (DEMO) (invited).

PubMed

McAdams, R

2014-02-01

In the development of magnetically confined fusion as an economically sustainable power source, International Tokamak Experimental Reactor (ITER) is currently under construction. Beyond ITER is the demonstration fusion reactor (DEMO) programme in which the physics and engineering aspects of a future fusion power plant will be demonstrated. DEMO will produce net electrical power. The DEMO programme will be outlined and the role of neutral beams for heating and current drive will be described. In particular, the importance of the efficiency of neutral beam systems in terms of injected neutral beam power compared to wallplug power will be discussed. Options for improving this efficiency including advanced neutralisers and energy recovery are discussed.

New amplifying laser concept for inertial fusion driver

NASA Astrophysics Data System (ADS)

Mourou, G. A.; Labaune, C.; Hulin, D.; Galvanauskas, A.

2008-05-01

This paper presents a new amplifying laser concept designed to produce high energy in either short or long pulses using coherent or incoherent addition of few millions fibers. These are called respectively CAN for Coherent Amplification Network and FAN for Fiber Amplification Network. The fibers would be large core or Large Mode Area (LMA) which have demonstrated up to 10, mJ output energy per fiber1. Such a system could meet the driver criteria of Inertial Fusion Energy (IFE) power plants based on Inertial Confinement Fusion (ICF), in particular high efficiency and high repetition rate.

Review of fusion synfuels

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fillo, J.A.

1980-01-01

Thermonuclear fusion offers an inexhaustible source of energy for the production of hydrogen from water. Depending on design, electric generation efficiencies of approx. 40 to 60% and hydrogen production efficiencies by high-temperature electrolysis of approx. 50 to 65% are projected for fusion reactors using high-temperatures blankets. Fusion/coal symbiotic systems appear economically promising for the first generation of commercial fusion synfuels plants. Coal production requirements and the environmental effects of large-scale coal usage would be greatly reduced by a fusion/coal system. In the long term, there could be a gradual transition to an inexhaustible energy system based solely on fusion.

High-Efficiency Food Production in a Renewable Energy Based Micro-Grid Power System

NASA Technical Reports Server (NTRS)

Bubenheim, David; Meiners, Dennis

2016-01-01

Controlled Environment Agriculture (CEA) systems can be used to produce high-quality, desirable food year round, and the fresh produce can positively contribute to the health and well being of residents in communities with difficult supply logistics. While CEA has many positive outcomes for a remote community, the associated high electric demands have prohibited widespread implementation in what is typically already a fully subscribed power generation and distribution system. Recent advances in CEA technologies as well as renewable power generation, storage, and micro-grid management are increasing system efficiency and expanding the possibilities for enhancing community supporting infrastructure without increasing demands for outside supplied fuels. We will present examples of how new lighting, nutrient delivery, and energy management and control systems can enable significant increases in food production efficiency while maintaining high yields in CEA. Examples from Alaskan communities where initial incorporation of renewable power generation, energy storage and grid management techniques have already reduced diesel fuel consumption for electric generation by more than 40% and expanded grid capacity will be presented. We will discuss how renewable power generation, efficient grid management to extract maximum community service per kW, and novel energy storage approaches can expand the food production, water supply, waste treatment, sanitation and other community support services without traditional increases of consumable fuels supplied from outside the community. These capabilities offer communities with a range of choices to enhance their communities. The examples represent a synergy of technology advancement efforts to develop sustainable community support systems for future space-based human habitats and practical implementation of infrastructure components to increase efficiency and enhance health and well being in remote communities today and tomorrow.

High Level Information Fusion (HLIF) with nested fusion loops

NASA Astrophysics Data System (ADS)

Woodley, Robert; Gosnell, Michael; Fischer, Amber

2013-05-01

Situation modeling and threat prediction require higher levels of data fusion in order to provide actionable information. Beyond the sensor data and sources the analyst has access to, the use of out-sourced and re-sourced data is becoming common. Through the years, some common frameworks have emerged for dealing with information fusion—perhaps the most ubiquitous being the JDL Data Fusion Group and their initial 4-level data fusion model. Since these initial developments, numerous models of information fusion have emerged, hoping to better capture the human-centric process of data analyses within a machine-centric framework. 21st Century Systems, Inc. has developed Fusion with Uncertainty Reasoning using Nested Assessment Characterizer Elements (FURNACE) to address challenges of high level information fusion and handle bias, ambiguity, and uncertainty (BAU) for Situation Modeling, Threat Modeling, and Threat Prediction. It combines JDL fusion levels with nested fusion loops and state-of-the-art data reasoning. Initial research has shown that FURNACE is able to reduce BAU and improve the fusion process by allowing high level information fusion (HLIF) to affect lower levels without the double counting of information or other biasing issues. The initial FURNACE project was focused on the underlying algorithms to produce a fusion system able to handle BAU and repurposed data in a cohesive manner. FURNACE supports analyst's efforts to develop situation models, threat models, and threat predictions to increase situational awareness of the battlespace. FURNACE will not only revolutionize the military intelligence realm, but also benefit the larger homeland defense, law enforcement, and business intelligence markets.

Evaluation of power transfer efficiency for a high power inductively coupled radio-frequency hydrogen ion source

NASA Astrophysics Data System (ADS)

Jain, P.; Recchia, M.; Cavenago, M.; Fantz, U.; Gaio, E.; Kraus, W.; Maistrello, A.; Veltri, P.

2018-04-01

Neutral beam injection (NBI) for plasma heating and current drive is necessary for International Thermonuclear Experimental reactor (ITER) tokamak. Due to its various advantages, a radio frequency (RF) driven plasma source type was selected as a reference ion source for the ITER heating NBI. The ITER relevant RF negative ion sources are inductively coupled (IC) devices whose operational working frequency has been chosen to be 1 MHz and are characterized by high RF power density (˜9.4 W cm-3) and low operational pressure (around 0.3 Pa). The RF field is produced by a coil in a cylindrical chamber leading to a plasma generation followed by its expansion inside the chamber. This paper recalls different concepts based on which a methodology is developed to evaluate the efficiency of the RF power transfer to hydrogen plasma. This efficiency is then analyzed as a function of the working frequency and in dependence of other operating source and plasma parameters. The study is applied to a high power IC RF hydrogen ion source which is similar to one simplified driver of the ELISE source (half the size of the ITER NBI source).

High Power Klystrons for Efficient Reliable High Power Amplifiers.

DTIC Science & Technology

1980-11-01

techniques to obtain high overall efficiency. One is second harmonic space charge bunching. This is a process whereby the fundamental and second harmonic...components of the space charge waves in the electron beam of a microwave tube are combined to produce more highly concentrated electron bunches raising the...the drift lengths to enhance the 2nd harmonic component in the space charge waves. The latter method was utilized in the VKC-7790. Computer

Hot Fusion: an efficient method to clone multiple DNA fragments as well as inverted repeats without ligase.

PubMed

Fu, Changlin; Donovan, William P; Shikapwashya-Hasser, Olga; Ye, Xudong; Cole, Robert H

2014-01-01

Molecular cloning is utilized in nearly every facet of biological and medical research. We have developed a method, termed Hot Fusion, to efficiently clone one or multiple DNA fragments into plasmid vectors without the use of ligase. The method is directional, produces seamless junctions and is not dependent on the availability of restriction sites for inserts. Fragments are assembled based on shared homology regions of 17-30 bp at the junctions, which greatly simplifies the construct design. Hot Fusion is carried out in a one-step, single tube reaction at 50 °C for one hour followed by cooling to room temperature. In addition to its utility for multi-fragment assembly Hot Fusion provides a highly efficient method for cloning DNA fragments containing inverted repeats for applications such as RNAi. The overall cloning efficiency is in the order of 90-95%.

High efficiency fourth-harmonic generation from nanosecond fiber master oscillator power amplifier

NASA Astrophysics Data System (ADS)

Mu, Xiaodong; Steinvurzel, Paul; Rose, Todd S.; Lotshaw, William T.; Beck, Steven M.; Clemmons, James H.

2016-03-01

We demonstrate high power, deep ultraviolet (DUV) conversion to 266 nm through frequency quadrupling of a nanosecond pulse width 1064 nm fiber master oscillator power amplifier (MOPA). The MOPA system uses an Yb-doped double-clad polarization-maintaining large mode area tapered fiber as the final gain stage to generate 0.5-mJ, 10 W, 1.7- ns single mode pulses at a repetition rate of 20 kHz with measured spectral bandwidth of 10.6 GHz (40 pm), and beam qualities of Mx 2=1.07 and My 2=1.03, respectively. Using LBO and BBO crystals for the second-harmonic generation (SHG) and fourth-harmonic generation (FHG), we have achieved 375 μJ (7.5 W) and 92.5 μJ (1.85 W) at wavelengths of 532 nm and 266 nm, respectively. To the best of our knowledge these are the highest narrowband infrared, green and UV pulse energies obtained to date from a fully spliced fiber amplifier. We also demonstrate high efficiency SHG and FHG with walk-off compensated (WOC) crystal pairs and tightly focused pump beam. An SHG efficiency of 75%, FHG efficiency of 47%, and an overall efficiency of 35% from 1064 nm to 266 nm are obtained.

High Efficiency Variable Speed Versatile Power Air Conditioning System for Military Vehicles

DTIC Science & Technology

2013-08-01

MOBILITY (P&M) MINI-SYMPOSIUM AUGUST 21-22, 2013 - TROY , MICHIGAN High efficiency variable speed versatile power air conditioning system for...power draw was measured using a calibrated Watt meter. The schematic of the setup is shown in Figure 5 and the setup is shown in Figure 6. Figure...Rocky Research environmental chamber. Cooling Capacity was directly measured in Btu/hr or Watts via measuring the Air flow velocity and the air

Stable, high power, high efficiency picosecond ultraviolet generation at 355 nm in K3B6O10 Br crystal

NASA Astrophysics Data System (ADS)

Hou, Z. Y.; Wang, L. R.; Xia, M. J.; Yan, D. X.; Zhang, Q. L.; Zhang, L.; Liu, L. J.; Xu, D. G.; Zhang, D. X.; Wang, X. Y.; Li, R. K.; Chen, C. T.

2018-06-01

We demonstrate a high efficiency and high power picosecond ultraviolet source at 355 nm with stable output by sum frequency generation from a Nd:YAG laser using a type-I critically phase matched K3B6O10 Br crystal as nonlinear optical material. Conversion efficiency as high as 30.8% was achieved using a 25 ps laser at 1064 nm operated at 10 Hz. Similar work is done by using a 35 W 10 ps laser at 1064 nm as the pump source with a repetition rate of 80 MHz, and the highest average output power obtained was up to 5.3 W. In addition, the power stability of the 355 nm output power measurement shows that the standard deviation fluctuations of the average power are ±0.69% and ±0.91% at 3.0 W and 3.5 W, respectively.

Lunar He-3, fusion propulsion, and space development

NASA Technical Reports Server (NTRS)

Santarius, John F.

1992-01-01

The recent identification of a substantial lunar resource of the fusion energy fuel He-3 may provide the first terrestrial market for a lunar commodity and, therefore, a major impetus to lunar development. The impact of this resource-when burned in D-He-3 fusion reactors for space power and propulsion-may be even more significant as an enabling technology for safe, efficient exploration and development of space. One possible reactor configuration among several options, the tandem mirror, illustrates the potential advantages of fusion propulsion. The most important advantage is the ability to provide either fast, piloted vessels or high-payload-fraction cargo vessels due to a range of specific impulses from 50 sec to 1,000,000 sec at thrust-to-weight ratios from 0.1 to 5x10(exp -5). Fusion power research has made steady, impressive progress. It is plausible, and even probable, that fusion rockets similar to the designs presented here will be available in the early part of the twenty-first century, enabling a major expansion of human presence into the solar system.

ADX: a high field, high power density, Advanced Divertor test eXperiment

NASA Astrophysics Data System (ADS)

Vieira, R.; Labombard, B.; Marmar, E.; Irby, J.; Shiraiwa, S.; Terry, J.; Wallace, G.; Whyte, D. G.; Wolfe, S.; Wukitch, S.; ADX Team

2014-10-01

The MIT PSFC and collaborators are proposing an advanced divertor experiment (ADX) - a tokamak specifically designed to address critical gaps in the world fusion research program on the pathway to FNSF/DEMO. This high field (6.5 tesla, 1.5 MA), high power density (P/S ~ 1.5 MW/m2) facility would utilize Alcator magnet technology to test innovative divertor concepts for next-step DT fusion devices (FNSF, DEMO) at reactor-level boundary plasma pressures and parallel heat flux densities while producing high performance core plasma conditions. The experimental platform would also test advanced lower hybrid current drive (LHCD) and ion-cyclotron range of frequency (ICRF) actuators and wave physics at the plasma densities and magnetic field strengths of a DEMO, with the unique ability to deploy launcher structures both on the low-magnetic-field side and the high-field side - a location where energetic plasma-material interactions can be controlled and wave physics is most favorable for efficient current drive, heating and flow drive. This innovative experiment would perform plasma science and technology R&D necessary to inform the conceptual development and accelerate the readiness-for-deployment of FNSF/DEMO - in a timely manner, on a cost-effective research platform. Supported by DE-FC02-99ER54512.

Hot Fusion: An Efficient Method to Clone Multiple DNA Fragments as Well as Inverted Repeats without Ligase

PubMed Central

Fu, Changlin; Donovan, William P.; Shikapwashya-Hasser, Olga; Ye, Xudong; Cole, Robert H.

2014-01-01

Molecular cloning is utilized in nearly every facet of biological and medical research. We have developed a method, termed Hot Fusion, to efficiently clone one or multiple DNA fragments into plasmid vectors without the use of ligase. The method is directional, produces seamless junctions and is not dependent on the availability of restriction sites for inserts. Fragments are assembled based on shared homology regions of 17–30 bp at the junctions, which greatly simplifies the construct design. Hot Fusion is carried out in a one-step, single tube reaction at 50°C for one hour followed by cooling to room temperature. In addition to its utility for multi-fragment assembly Hot Fusion provides a highly efficient method for cloning DNA fragments containing inverted repeats for applications such as RNAi. The overall cloning efficiency is in the order of 90–95%. PMID:25551825

Investigating Data Motion Power Trends to Enable Power-Efficient OpenSHMEM Implementations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mintz, Tiffany M; D'Azevedo, Eduardo F.; Gorentla Venkata, Manjunath

2016-01-01

As we continue to develop extreme-scale systems, it is becoming increasingly important to be mindful and more in control of power consumed by these systems. With high performance requirements being more constrained by power and data movement quickly becoming the critical concern for both power and performance, now is an opportune time for OpenSHMEM implementations to address the need for more power-efficient data movement. In order to enable power efficient OpenSHMEM implementations, we have formulated power trend studies that emphasize power consumption for one-sided communications and the disparities in power consumption across multiple implementations. In this paper, we present powermore » trend analysis, generate targeted hypotheses for increasing power efficiency with OpenSHMEM, and discuss prospective research for power efficient OpenSHMEM implementations.« less

Extended Logic Intelligent Processing System for a Sensor Fusion Processor Hardware

NASA Technical Reports Server (NTRS)

Stoica, Adrian; Thomas, Tyson; Li, Wei-Te; Daud, Taher; Fabunmi, James

2000-01-01

The paper presents the hardware implementation and initial tests from a low-power, highspeed reconfigurable sensor fusion processor. The Extended Logic Intelligent Processing System (ELIPS) is described, which combines rule-based systems, fuzzy logic, and neural networks to achieve parallel fusion of sensor signals in compact low power VLSI. The development of the ELIPS concept is being done to demonstrate the interceptor functionality which particularly underlines the high speed and low power requirements. The hardware programmability allows the processor to reconfigure into different machines, taking the most efficient hardware implementation during each phase of information processing. Processing speeds of microseconds have been demonstrated using our test hardware.

Magnetic-confinement fusion

NASA Astrophysics Data System (ADS)

Ongena, J.; Koch, R.; Wolf, R.; Zohm, H.

2016-05-01

Our modern society requires environmentally friendly solutions for energy production. Energy can be released not only from the fission of heavy nuclei but also from the fusion of light nuclei. Nuclear fusion is an important option for a clean and safe solution for our long-term energy needs. The extremely high temperatures required for the fusion reaction are routinely realized in several magnetic-fusion machines. Since the early 1990s, up to 16 MW of fusion power has been released in pulses of a few seconds, corresponding to a power multiplication close to break-even. Our understanding of the very complex behaviour of a magnetized plasma at temperatures between 150 and 200 million °C surrounded by cold walls has also advanced substantially. This steady progress has resulted in the construction of ITER, a fusion device with a planned fusion power output of 500 MW in pulses of 400 s. ITER should provide answers to remaining important questions on the integration of physics and technology, through a full-size demonstration of a tenfold power multiplication, and on nuclear safety aspects. Here we review the basic physics underlying magnetic fusion: past achievements, present efforts and the prospects for future production of electrical energy. We also discuss questions related to the safety, waste management and decommissioning of a future fusion power plant.

Development of D+3He Fusion Electric Thrusters and Power Supplies for Space

NASA Astrophysics Data System (ADS)

Morse, Thomas M.

1994-07-01

Development of D+3He Fusion Electric Thrusters (FET) and Power Supplies (FPS) should occur at a lunar base because of the following: availability of helium-3, a vacuum better than on Earth, low K in shade reachable by radiant cooling, supply of ``high temp'' superconducting ceramic-metals, and a low G environment. The early FET will be much smaller than an Apollo engine, with specific impulse of 10,000-100,000-s. Solar power and low G will aid early development. To counter the effect of low G on humans, centrifuges will be employed for sleeping and resting. Work will be done by telerobotic view control. The FPS will be of comparable size, and will generate power mainly by having replaceable rectennas, resonant to the fusion synchrotron radiation. FPSs are used for house keeping power and initiating superconduction. Spaceships will carry up to ten FETs and two FPSs. In addition to fusion fuel, the FET will inject H or Li low mass propellant into the fusion chamber. Developing an FET would be difficult on Earth. FET spaceships will park between missions in L1, and an FET Bus will fetch humans/supplies from Moon and Earth. Someday FETs, with rocket assist, will lift spaceships from Earth, and make space travel to planets far cheaper, faster, and safer, than at present. Too long a delay due to the space station, or the huge cost of getting into space by current means, will damage the morale of the space program.

Analysis and design of high-power and efficient, millimeter-wave power amplifier systems using zero degree combiners

NASA Astrophysics Data System (ADS)

Tai, Wei; Abbasi, Mortez; Ricketts, David S.

2018-01-01

We present the analysis and design of high-power millimetre-wave power amplifier (PA) systems using zero-degree combiners (ZDCs). The methodology presented optimises the PA device sizing and the number of combined unit PAs based on device load pull simulations, driver power consumption analysis and loss analysis of the ZDC. Our analysis shows that an optimal number of N-way combined unit PAs leads to the highest power-added efficiency (PAE) for a given output power. To illustrate our design methodology, we designed a 1-W PA system at 45 GHz using a 45 nm silicon-on-insulator process and showed that an 8-way combined PA has the highest PAE that yields simulated output power of 30.6 dBm and 31% peak PAE.

High-Energy Space Propulsion Based on Magnetized Target Fusion

NASA Technical Reports Server (NTRS)

Thio, Y. C. F.; Landrum, D. B.; Freeze, B.; Kirkpatrick, R. C.; Gerrish, H.; Schmidt, G. R.

1999-01-01

Magnetized target fusion is an approach in which a magnetized target plasma is compressed inertially by an imploding material wall. A high energy plasma liner may be used to produce the required implosion. The plasma liner is formed by the merging of a number of high momentum plasma jets converging towards the center of a sphere where two compact toroids have been introduced. Preliminary 3-D hydrodynamics modeling results using the SPHINX code of Los Alamos National Laboratory have been very encouraging and confirm earlier theoretical expectations. The concept appears ready for experimental exploration and plans for doing so are being pursued. In this talk, we explore conceptually how this innovative fusion approach could be packaged for space propulsion for interplanetary travel. We discuss the generally generic components of a baseline propulsion concept including the fusion engine, high velocity plasma accelerators, generators of compact toroids using conical theta pinches, magnetic nozzle, neutron absorption blanket, tritium reprocessing system, shock absorber, magnetohydrodynamic generator, capacitor pulsed power system, thermal management system, and micrometeorite shields.

High power tapered lasers with optimized photonic crystal structure for low divergence and high efficiency

NASA Astrophysics Data System (ADS)

Ma, Xiaolong; Qu, Hongwei; Qi, Aiyi; Zhou, Xuyan; Ma, Pijie; Liu, Anjin; Zheng, Wanhua

2018-04-01

High power tapered lasers are designed and fabricated. A one-dimensional photonic crystal structure in the vertical direction is adopted to narrow the far field divergence. The thickness of the defect layer and the photonic crystal layers are optimized by analyzing the optical field theoretically. For tapered lasers, the continuous-wave power is 7.3 W and the pulsed power is 17 W. A maximum wall-plug efficiency of 46% under continuous-wave operation and 49.3% in pulsed mode are obtained. The beam divergences are around 11° and 6° for the vertical and lateral directions, respectively. High beam qualities are also obtained with a vertical M2 value of 1.78 and a lateral M2 value of 1.62. As the current increases, the lateral M2 value increases gradually while the vertical M2 value remains around 2.

Fusion Propulsion and Power for Future Flight

NASA Technical Reports Server (NTRS)

Froning, H. D., Jr.

1996-01-01

There are innovative magnetic and electric confinement fusion power and propulsion system designs with potential for: vacuum specific impulses of 1500-2000 seconds with rocket engine thrust/mass ratios of 5-10 g's; environmentally favorable exhaust emissions if aneutronic fusion propellants can be used; a 2 to 3-fold reduction in the mass of hypersonic airliners and SSTO aerospace planes; a 10 to 20 fold reduction in Mars expedition mass and cost (if propellant from planetary atmospheres is used); and feasibility or in-feasibility of these systems could be confirmed with a modest applied research and exploratory development cost.

Field-Reversed Configuration Power Plant Critical-Issue Scoping Study

DOE Office of Scientific and Technical Information (OSTI.GOV)

Santarius, J. F.; Mogahed, E. A.; Emmert, G. A.

A team from the Universities of Wisconsin, Washington, and Illinois performed an engineering scoping study of critical issues for field-reversed configuration (FRC) power plants. The key tasks for this research were (1) systems analysis for deuterium-tritium (D-T) FRC fusion power plants, and (2) conceptual design of the blanket and shield module for an FRC fusion core. For the engineering conceptual design of the fusion core, the project team focused on intermediate-term technology. For example, one decision was to use steele structure. The FRC systems analysis led to a fusion power plant with attractive features including modest size, cylindrical symmetry, goodmore » thermal efficiency (52%), relatively easy maintenance, and a high ratio of electric power to fusion core mass, indicating that it would have favorable economics.« less

A Fusion Protein of the p53 Transaction Domain and the p53-Binding Domain of the Oncoprotein MdmX as an Efficient System for High-Throughput Screening of MdmX Inhibitors.

PubMed

Chen, Rong; Zhou, Jingjing; Qin, Lingyun; Chen, Yao; Huang, Yongqi; Liu, Huili; Su, Zhengding

2017-06-27

In nearly half of cancers, the anticancer activity of p53 protein is often impaired by the overexpressed oncoprotein Mdm2 and its homologue, MdmX, demanding efficient therapeutics to disrupt the aberrant p53-MdmX/Mdm2 interactions to restore the p53 activity. While many potent Mdm2-specific inhibitors have already undergone clinical investigations, searching for MdmX-specific inhibitors has become very attractive, requiring a more efficient screening strategy for evaluating potential scaffolds or leads. In this work, considering that the intrinsic fluorescence residue Trp23 in the p53 transaction domain (p53p) plays an important role in determining the p53-MdmX/Mdm2 interactions, we constructed a fusion protein to utilize this intrinsic fluorescence signal to monitor high-throughput screening of a compound library. The fusion protein was composed of the p53p followed by the N-terminal domain of MdmX (N-MdmX) through a flexible amino acid linker, while the whole fusion protein contained a sole intrinsic fluorescence probe. The fusion protein was then evaluated using fluorescence spectroscopy against model compounds. Our results revealed that the variation of the fluorescence signal was highly correlated with the concentration of the ligand within 65 μM. The fusion protein was further evaluated with respect to its feasibility for use in high-throughput screening using a model compound library, including controls. We found that the imidazo-indole scaffold was a bona fide scaffold for template-based design of MdmX inhibitors. Thus, the p53p-N-MdmX fusion protein we designed provides a convenient and efficient tool for high-throughput screening of new MdmX inhibitors. The strategy described in this work should be applicable for other protein targets to accelerate drug discovery.

Fusion energy for space missions in the 21st century: Executive summary

NASA Technical Reports Server (NTRS)

Schulze, Norman R.

1991-01-01

Future space missions were hypothesized and analyzed, and the energy source of their accomplishment investigated. The missions included manned Mars, scientific outposts to and robotic sample return missions from the outer planets and asteroids, as well as fly-by and rendezvous missions with the Oort Cloud and the nearest star, Alpha Centauri. Space system parametric requirements and operational features were established. The energy means for accomplishing missions where delta v requirements range from 90 km/sec to 30,000 km/sec (High Energy Space Mission) were investigated. The need to develop a power space of this magnitude is a key issue to address if the U.S. civil space program is to continue to advance as mandated by the National Space Policy. Potential energy options which could provide the propulsion and electrical power system and operational requirements were reviewed and evaluated. Fusion energy was considered to be the preferred option and was analyzed in depth. Candidate fusion fuels were evaluated based upon the energy output and neutron flux. Additionally, fusion energy can offer significant safety, environmental, economic, and operational advantages. Reactors exhibiting a highly efficient use of magnetic fields for space use while at the same time offering efficient coupling to an exhaust propellant or to a direct energy convertor for efficient electrical production were examined. Near term approaches were identified. A strategy that will produce fusion powered vehicles as part of the space transportation infrastructure was developed. Space program resources must be directed toward this issue as a matter of the top policy priority.

Magnetized Target Fusion

NASA Technical Reports Server (NTRS)

Griffin, Steven T.

2002-01-01

Magnetized target fusion (MTF) is under consideration as a means of building a low mass, high specific impulse, and high thrust propulsion system for interplanetary travel. This unique combination is the result of the generation of a high temperature plasma by the nuclear fusion process. This plasma can then be deflected by magnetic fields to provide thrust. Fusion is initiated by a small traction of the energy generated in the magnetic coils due to the plasma's compression of the magnetic field. The power gain from a fusion reaction is such that inefficiencies due to thermal neutrons and coil losses can be overcome. Since the fusion reaction products are directly used for propulsion and the power to initiate the reaction is directly obtained from the thrust generation, no massive power supply for energy conversion is required. The result should be a low engine mass, high specific impulse and high thrust system. The key is to successfully initiate fusion as a proof-of-principle for this application. Currently MSFC is implementing MTF proof-of-principle experiments. This involves many technical details and ancillary investigations. Of these, selected pertinent issues include the properties, orientation and timing of the plasma guns and the convergence and interface development of the "pusher" plasma. Computer simulations of the target plasma's behavior under compression and the convergence and mixing of the gun plasma are under investigation. This work is to focus on the gun characterization and development as it relates to plasma initiation and repeatability.

Developing structural, high-heat flux and plasma facing materials for a near-term DEMO fusion power plant: The EU assessment

NASA Astrophysics Data System (ADS)

Stork, D.; Agostini, P.; Boutard, J. L.; Buckthorpe, D.; Diegele, E.; Dudarev, S. L.; English, C.; Federici, G.; Gilbert, M. R.; Gonzalez, S.; Ibarra, A.; Linsmeier, Ch.; Li Puma, A.; Marbach, G.; Morris, P. F.; Packer, L. W.; Raj, B.; Rieth, M.; Tran, M. Q.; Ward, D. J.; Zinkle, S. J.

2014-12-01

The findings of the EU 'Materials Assessment Group' (MAG), within the 2012 EU Fusion Roadmap exercise, are discussed. MAG analysed the technological readiness of structural, plasma facing and high heat flux materials for a DEMO concept to be constructed in the early 2030s, proposing a coherent strategy for R&D up to a DEMO construction decision. A DEMO phase I with a 'Starter Blanket' and 'Starter Divertor' is foreseen: the blanket being capable of withstanding ⩾2 MW yr m-2 fusion neutron fluence (∼20 dpa in the front-wall steel). A second phase ensues for DEMO with ⩾5 MW yr m-2 first wall neutron fluence. Technical consequences for the materials required and the development, testing and modelling programmes, are analysed using: a systems engineering approach, considering reactor operational cycles, efficient maintenance and inspection requirements, and interaction with functional materials/coolants; and a project-based risk analysis, with R&D to mitigate risks from material shortcomings including development of specific risk mitigation materials. The DEMO balance of plant constrains the blanket and divertor coolants to remain unchanged between the two phases. The blanket coolant choices (He gas or pressurised water) put technical constraints on the blanket steels, either to have high strength at higher temperatures than current baseline variants (above 650 °C for high thermodynamic efficiency from He-gas coolant), or superior radiation-embrittlement properties at lower temperatures (∼290-320 °C), for construction of water-cooled blankets. Risk mitigation proposed would develop these options in parallel, and computational and modelling techniques to shorten the cycle-time of new steel development will be important to achieve tight R&D timescales. The superior power handling of a water-cooled divertor target suggests a substructure temperature operating window (∼200-350 °C) that could be realised, as a baseline-concept, using tungsten on a copper

PBFA II, a 100 TW Pulsed Power Driver for the Inertial Confinement Fusion Program

DTIC Science & Technology

1985-06-01

providing a 30 MV, 15 ns output pulse,which accelerates lithium ions. The ions will focus onto a pellet containing deuterium-tritium, producing fusion ... energy . Several research areas will be reviewed: low jitter, highly reliable 370 kJ Marx generators; highly synchronized gas switching at 5 MV; efficient

High Temperature Fusion Reactor Cooling Using Brayton Cycle Based Partial Energy Conversion

NASA Astrophysics Data System (ADS)

Juhasz, Albert J.; Sawicki, Jerzy T.

2004-02-01

For some future space power systems using high temperature nuclear heat sources most of the output energy will be used in other than electrical form, and only a fraction of the total thermal energy generated will need to be converted to electrical work. The paper describes the conceptual design of such a ``partial energy conversion'' system, consisting of a high temperature fusion reactor operating in series with a high temperature radiator and in parallel with dual closed cycle gas turbine (CCGT) power systems, also referred to as closed Brayton cycle (CBC) systems, which are supplied with a fraction of the reactor thermal energy for conversion to electric power. Most of the fusion reactor's output is in the form of charged plasma which is expanded through a magnetic nozzle of the interplanetary propulsion system. Reactor heat energy is ducted to the high temperature series radiator utilizing the electric power generated to drive a helium gas circulation fan. In addition to discussing the thermodynamic aspects of the system design the authors include a brief overview of the gas turbine and fan rotor-dynamics and proposed bearing support technology along with performance characteristics of the three phase AC electric power generator and fan drive motor.

High Temperature Fusion Reactor Cooling Using Brayton Cycle Based Partial Energy Conversion

NASA Technical Reports Server (NTRS)

Juhasz, Albert J.; Sawicki, Jerzy T.

2003-01-01

For some future space power systems using high temperature nuclear heat sources most of the output energy will be used in other than electrical form, and only a fraction of the total thermal energy generated will need to be converted to electrical work. The paper describes the conceptual design of such a partial energy conversion system, consisting of a high temperature fusion reactor operating in series with a high temperature radiator and in parallel with dual closed cycle gas turbine (CCGT) power systems, also referred to as closed Brayton cycle (CBC) systems, which are supplied with a fraction of the reactor thermal energy for conversion to electric power. Most of the fusion reactor's output is in the form of charged plasma which is expanded through a magnetic nozzle of the interplanetary propulsion system. Reactor heat energy is ducted to the high temperature series radiator utilizing the electric power generated to drive a helium gas circulation fan. In addition to discussing the thermodynamic aspects of the system design the authors include a brief overview of the gas turbine and fan rotor-dynamics and proposed bearing support technology along with performance characteristics of the three phase AC electric power generator and fan drive motor.

Electrical heating of soils using high efficiency electrode patterns and power phases

DOEpatents

Buettner, Harley M.

1999-01-01

Powerline-frequency electrical (joule) heating of soils using a high efficiency electrode configuration and power phase arrangement. The electrode configuration consists of several heating or current injection electrodes around the periphery of a volume of soil to be heated, all electrodes being connected to one phase of a multi-phase or a single-phase power system, and a return or extraction electrode or electrodes located inside the volume to be heated being connected to the remaining phases of the multi-phase power system or to the neutral side of the single-phase power source. This electrode configuration and power phase arrangement can be utilized anywhere where powerline frequency soil heating is applicable and thus has many potential uses including removal of volatile organic compounds such as gasoline and tricholorethylene (TCE) from contaminated areas.

Gasification of high ash, high ash fusion temperature bituminous coals

DOEpatents

Liu, Guohai; Vimalchand, Pannalal; Peng, WanWang

2015-11-13

This invention relates to gasification of high ash bituminous coals that have high ash fusion temperatures. The ash content can be in 15 to 45 weight percent range and ash fusion temperatures can be in 1150.degree. C. to 1500.degree. C. range as well as in excess of 1500.degree. C. In a preferred embodiment, such coals are dealt with a two stage gasification process--a relatively low temperature primary gasification step in a circulating fluidized bed transport gasifier followed by a high temperature partial oxidation step of residual char carbon and small quantities of tar. The system to process such coals further includes an internally circulating fluidized bed to effectively cool the high temperature syngas with the aid of an inert media and without the syngas contacting the heat transfer surfaces. A cyclone downstream of the syngas cooler, operating at relatively low temperatures, effectively reduces loading to a dust filtration unit. Nearly dust- and tar-free syngas for chemicals production or power generation and with over 90%, and preferably over about 98%, overall carbon conversion can be achieved with the preferred process, apparatus and methods outlined in this invention.

Research on the Automatic Fusion Strategy of Fixed Value Boundary Based on the Weak Coupling Condition of Grid Partition

NASA Astrophysics Data System (ADS)

Wang, X. Y.; Dou, J. M.; Shen, H.; Li, J.; Yang, G. S.; Fan, R. Q.; Shen, Q.

2018-03-01

With the continuous strengthening of power grids, the network structure is becoming more and more complicated. An open and regional data modeling is used to complete the calculation of the protection fixed value based on the local region. At the same time, a high precision, quasi real-time boundary fusion technique is needed to seamlessly integrate the various regions so as to constitute an integrated fault computing platform which can conduct transient stability analysis of covering the whole network with high accuracy and multiple modes, deal with the impact results of non-single fault, interlocking fault and build “the first line of defense” of the power grid. The boundary fusion algorithm in this paper is an automatic fusion algorithm based on the boundary accurate coupling of the networking power grid partition, which takes the actual operation mode for qualification, complete the boundary coupling algorithm of various weak coupling partition based on open-loop mode, improving the fusion efficiency, truly reflecting its transient stability level, and effectively solving the problems of too much data, too many difficulties of partition fusion, and no effective fusion due to mutually exclusive conditions. In this paper, the basic principle of fusion process is introduced firstly, and then the method of boundary fusion customization is introduced by scene description. Finally, an example is given to illustrate the specific algorithm on how it effectively implements the boundary fusion after grid partition and to verify the accuracy and efficiency of the algorithm.

Tritium Breeding Blanket for a Commercial Fusion Power Plant - A System Engineering Assessment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Meier, Wayne R.

The goal of developing a new source of electric power based on fusion has been pursued for decades. If successful, future fusion power plants will help meet growing world-wide demand for electric power. A key feature and selling point for fusion is that its fuel supply is widely distributed globally and virtually inexhaustible. Current world-wide research on fusion energy is focused on the deuterium-tritium (DT for short) fusion reaction since it will be the easiest to achieve in terms of the conditions (e.g., temperature, density and confinement time of the DT fuel) required to produce net energy. Over the pastmore » decades countless studies have examined various concepts for TBBs for both magnetic fusion energy (MFE) and inertial fusion energy (IFE). At this time, the key organizations involved are government sponsored research organizations world-wide. The near-term focus of the MFE community is on the development of TBB mock-ups to be tested on the ITER tokamak currently under construction in Caderache France. TBB concepts for IFE tend to be different from MFE primarily due to significantly different operating conditions and constraints. This report focuses on longer-term commercial power plants where the key stakeholders include: electric utilities, plant owner and operator, manufacturer, regulators, utility customers, and in-plant subsystems including the heat transfer and conversion systems, fuel processing system, plant safety systems, and the monitoring control systems.« less

Neural network fusion capabilities for efficient implementation of tracking algorithms

NASA Astrophysics Data System (ADS)

Sundareshan, Malur K.; Amoozegar, Farid

1997-03-01

The ability to efficiently fuse information of different forms to facilitate intelligent decision making is one of the major capabilities of trained multilayer neural networks that is now being recognized. While development of innovative adaptive control algorithms for nonlinear dynamical plants that attempt to exploit these capabilities seems to be more popular, a corresponding development of nonlinear estimation algorithms using these approaches, particularly for application in target surveillance and guidance operations, has not received similar attention. We describe the capabilities and functionality of neural network algorithms for data fusion and implementation of tracking filters. To discuss details and to serve as a vehicle for quantitative performance evaluations, the illustrative case of estimating the position and velocity of surveillance targets is considered. Efficient target- tracking algorithms that can utilize data from a host of sensing modalities and are capable of reliably tracking even uncooperative targets executing fast and complex maneuvers are of interest in a number of applications. The primary motivation for employing neural networks in these applications comes from the efficiency with which more features extracted from different sensor measurements can be utilized as inputs for estimating target maneuvers. A system architecture that efficiently integrates the fusion capabilities of a trained multilayer neural net with the tracking performance of a Kalman filter is described. The innovation lies in the way the fusion of multisensor data is accomplished to facilitate improved estimation without increasing the computational complexity of the dynamical state estimator itself.

Magnetic fusion commercial power plants

NASA Astrophysics Data System (ADS)

Sheffield, J.

Toroidal magnetic systems present the best opportunity to make a commercial fusion power plant. They offer potential solutions to the main requirements that confront a power plant designer. An ideal system may be postulated in which the coils are a very small part of the cost, and the cost stems primarily from the inescapable components: minimal plasma heating (and sustaining system), tritium breeding blanket, shield, particle input, removal and treatment system, heat transfer system, generators, buildings, and balance of plant. No present system meets the ideal standards; however, toroidal systems contain among them the elements required. Consequently, a logical program may be based upon an evolutionary development, building on the contributions of the tokamak, which has been the mainline of research for a number of years.

Cost Modeling and Design of Field-Reversed Configuration Fusion Power Plants

NASA Astrophysics Data System (ADS)

Kirtley, David; Slough, John; Helion Team

2017-10-01

The Inductively Driven Liner (IDL) fusion concept uses the magnetically driven implosion of thin (0.5-1 mm) Aluminum hoops to magnetically compress a merged Field-Reversed Configuration (FRC) plasma to fusion conditions. Both the driver and the target have been studied experimentally and theoretically by researchers at Helion Energy, MSNW, and the University of Washington, demonstrating compression fields greater than 100 T and suitable fusion targets. In the presented study, a notional power plant facility using this approach will be described. In addition, a full cost study based on the LLNL Z-IFE and HYLIFE-II studies, the ARIES Tokamak concept, and RAND power plant studies will be described. Finally, the expected capital costs, development requirements, and LCOE for 50 and 500 MW power plants will be given. This analysis includes core FRC plant scaling, metallic liner recycling, radiation shielding, operations, and facilities capital requirements.

Rapid heating of matter using high power lasers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bang, Woosuk

2016-04-08

This slide presentation describes motivation (uniform and rapid heating of a target, opportunity to study warm dense matter, study of nuclear fusion reactions), rapid heating of matter with intense laser-driven ion beams, visualization of the expanding warm dense gold and diamond, and nuclear fusion experiments using high power lasers (direct heating of deuterium spheres (radius ~ 10nm) with an intense laser pulse.

Should the US abandon efforts to develop commercial fusion power

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kay, W.D.; Kinter, E.E.

1993-01-22

This article presents viewpoints and rationale for continuing and disbanding the US efforts to develop commercial fusion power. The views of W.D. Kay, an assistant professor of political science at Northeastern University, are presented regarding - yes, abandon efforts. Meanwhile, the views of Edwin Keutes, former director of the Magnetic Fusion Program for DOE, are presented for continued development.

High-efficiency power transfer for silicon-based photonic devices

NASA Astrophysics Data System (ADS)

Son, Gyeongho; Yu, Kyoungsik

2018-02-01

We demonstrate an efficient coupling of guided light of 1550 nm from a standard single-mode optical fiber to a silicon waveguide using the finite-difference time-domain method and propose a fabrication method of tapered optical fibers for efficient power transfer to silicon-based photonic integrated circuits. Adiabatically-varying fiber core diameters with a small tapering angle can be obtained using the tube etching method with hydrofluoric acid and standard single-mode fibers covered by plastic jackets. The optical power transmission of the fundamental HE11 and TE-like modes between the fiber tapers and the inversely-tapered silicon waveguides was calculated with the finite-difference time-domain method to be more than 99% at a wavelength of 1550 nm. The proposed method for adiabatic fiber tapering can be applied in quantum optics, silicon-based photonic integrated circuits, and nanophotonics. Furthermore, efficient coupling within the telecommunication C-band is a promising approach for quantum networks in the future.

Highly efficient X-range AlGaN/GaN power amplifier

NASA Astrophysics Data System (ADS)

Tural'chuk, P. A.; Kirillov, V. V.; Osipov, P. E.; Vendik, I. B.; Vendik, O. G.; Parnes, M. D.

2017-09-01

The development of microwave power amplifiers (PAs) based on transistors with an AlGaN/GaN heterojunction are discussed in terms of the possible enhancement of their efficiency. The main focus is on the synthesis of the transforming circuits, which ensure the reactive load at the second- and third-harmonic frequencies and complex impedance at the fundamental frequency. This makes it possible to optimize the complex operation mode of a PA; i.e., to reduce the scattering power and enhance the efficiency. A microwave PA based on the Schottky-barrier-gate field-effect transistor with 80 electrodes based on the GaN pHEMT transistor with a gate length of 0.25 nm and a gate width of 125 nm is experimentally investigated. The amplifier has a pulse output power of 35 W and a power-added efficiency of at least 50% at a working frequency of 9 GHz.

Power and Efficiency.

ERIC Educational Resources Information Center

Boyd, James N.

1991-01-01

Presents a mathematical problem that, when examined and generalized, develops the relationships between power and efficiency in energy transfer. Offers four examples of simple electrical and mechanical systems to illustrate the principle that maximum power occurs at 50 percent efficiency. (MDH)

Space fusion energy conversion using a field reversed configuration reactor: A new technical approach for space propulsion and power

NASA Technical Reports Server (NTRS)

Schulze, Norman R.; Miley, George H.; Santarius, John F.

1991-01-01

The fusion energy conversion design approach, the Field Reversed Configuration (FRC) - when burning deuterium and helium-3, offers a new method and concept for space transportation with high energy demanding programs, like the Manned Mars Mission and planetary science outpost missions require. FRC's will increase safety, reduce costs, and enable new missions by providing a high specific power propulsion system from a high performance fusion engine system that can be optimally designed. By using spacecraft powered by FRC's the space program can fulfill High Energy Space Missions (HESM) in a manner not otherwise possible. FRC's can potentially enable the attainment of high payload mass fractions while doing so within shorter flight times.

Plasma Power Station with Quasi Spherical Direct Drive Capsule for Fusion Yield and Inverse Diode for Driver-Target Coupling

DOE PAGES

VanDevender, J. P.; Cuneo, M. E.; Slutz, S. A.; ...

2012-01-01

The Meier-Moir economic model for Pulsed Power Driven Inertial Fusion Energy shows at least two approaches for fusion energy at 7 to 8 cents/kw-hr: One with large yield at 0.1 Hz and presented by M. E. Cuneo at ICENES 2011 and one with smaller yield at 3 Hz presented in this paper. Both use very efficient and low cost Linear Transformer Drivers (LTDs) for the pulsed power. Here, we report the system configuration and end-to-end simulation for the latter option, which is called the Plasma Power Station (PPS), and report the first results on the two, least mature, enabling technologies:more » a magnetically driven Quasi Spherical Direct Drive (QSDD) capsule for the fusion yield and an Inverse Diode for coupling the driver to the target. In addition, we describe the issues and propose to address the issues with a prototype of the PPS on the Saturn accelerator and with experiments on a short pulse modification of the Z accelerator test the validity of simulations showing megajoule thermonuclear yield with DT on a modified Z.« less

High-power waveguide resonator second harmonic device with external conversion efficiency up to 75%

NASA Astrophysics Data System (ADS)

Stefszky, M.; Ricken, R.; Eigner, C.; Quiring, V.; Herrmann, H.; Silberhorn, C.

2018-06-01

We report on a highly efficient waveguide resonator device for the production of 775 nm light using a titanium indiffused LiNbO3 waveguide resonator. When scanning the resonance, the device produces up to 110 mW of second harmonic power with 140 mW incident on the device—an external conversion efficiency of 75%. The cavity length is also locked, using a Pound–Drever–Hall type locking scheme, involving feedback to either the cavity temperature or the laser frequency. With laser frequency feedback, a stable output power of approximately 28 mW from a 52 mW pump is seen over one hour.

Flywheel induction motor-generator for magnet power supply in small fusion device

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hatakeyma, S., E-mail: hatakeyama.shoichi@torus.nr.titech.ac.jp; Yoshino, F.; Tsutsui, H.

2016-04-15

A flywheel motor-generator (MG) for the toroidal field (TF) coils of a small fusion device was developed which utilizes a commercially available squirrel-cage induction motor. Advantages of the MG are comparably-long duration, quick power response, and easy implementation of power control compared with conventional capacitor-type power supply. A 55-kW MG was fabricated, and TF coils of a small fusion device were energized. The duration of the current flat-top was extended to 1 s which is much longer than those of conventional small devices (around 10–100 ms).

Flywheel induction motor-generator for magnet power supply in small fusion device.

PubMed

Hatakeyma, S; Yoshino, F; Tsutsui, H; Tsuji-Iio, S

2016-04-01

A flywheel motor-generator (MG) for the toroidal field (TF) coils of a small fusion device was developed which utilizes a commercially available squirrel-cage induction motor. Advantages of the MG are comparably-long duration, quick power response, and easy implementation of power control compared with conventional capacitor-type power supply. A 55-kW MG was fabricated, and TF coils of a small fusion device were energized. The duration of the current flat-top was extended to 1 s which is much longer than those of conventional small devices (around 10-100 ms).

The Pulsed Fission-Fusion (PUFF) Concept for Deep Space Exploration and Terrestrial Power Generation

NASA Technical Reports Server (NTRS)

Adams, Robert; Cassibry, Jason; Schillo, Kevin

2017-01-01

This team is exploring a modified Z-pinch geometry as a propulsion system, imploding a liner of liquid lithium onto a pellet containing both fission and fusion fuel. The plasma resulting from the fission and fusion burn expands against a magnetic nozzle, for propulsion, or a magnetic confinement system, for terrestrial power generation. There is considerable synergy in the concept; the lithium acts as a temporary virtual cathode, and adds reaction mass for propulsion. Further, the lithium acts as a radiation shield against generated neutrons and gamma rays. Finally, the density profile of the column can be tailored using the lithium sheath. Recent theoretical and experimental developments (e.g. tailored density profile in the fuel injection, shear stabilization, and magnetic shear stabilization) have had great success in mitigating instabilities that have plagued previous fusion efforts. This paper will review the work in evaluating the pellet sizes and z-pinch conditions for optimal PuFF propulsion. Trades of pellet size and composition with z-pinch power levels and conditions for the tamper and lithium implosion are evaluated. Current models, both theoretical and computational, show that a z-pinch can ignite a small (1 cm radius) fission-fusion target with significant yield. Comparison is made between pure fission and boosted fission targets. Performance is shown for crewed spacecraft for high speed Mars round trip missions and near interstellar robotic missions. The PuFF concept also offers a solution for terrestrial power production. PuFF can, with recycling of the effluent, achieve near 100% burnup of fission fuel, providing a very attractive power source with minimal waste. The small size of PuFF relative to today's plants enables a more distributed power network and less exposure to natural or man-made disruptions.

CONFERENCE REPORT: Summary of the 8th IAEA Technical Meeting on Fusion Power Plant Safety

NASA Astrophysics Data System (ADS)

Girard, J. Ph.; Gulden, W.; Kolbasov, B.; Louzeiro-Malaquias, A.-J.; Petti, D.; Rodriguez-Rodrigo, L.

2008-01-01

Reports were presented covering a selection of topics on the safety of fusion power plants. These included a review on licensing studies developed for ITER site preparation surveying common and non-common issues (i.e. site dependent) as lessons to a broader approach for fusion power plant safety. Several fusion power plant models, spanning from accessible technology to more advanced-materials based concepts, were discussed. On the topic related to fusion-specific technology, safety studies were reported on different concepts of breeding blanket modules, tritium handling and auxiliary systems under normal and accident scenarios' operation. The testing of power plant relevant technology in ITER was also assessed in terms of normal operation and accident scenarios, and occupational doses and radioactive releases under these testings have been determined. Other specific safety issues for fusion have also been discussed such as availability and reliability of fusion power plants, dust and tritium inventories and component failure databases. This study reveals that the environmental impact of fusion power plants can be minimized through a proper selection of low activation materials and using recycling technology helping to reduce waste volume and potentially open the route for its reutilization for the nuclear sector or even its clearance into the commercial circuit. Computational codes for fusion safety have been presented in support of the many studies reported. The on-going work on establishing validation approaches aiming at improving the prediction capability of fusion codes has been supported by experimental results and new directions for development have been identified. Fusion standards are not available and fission experience is mostly used as the framework basis for licensing and target design for safe operation and occupational and environmental constraints. It has been argued that fusion can benefit if a specific fusion approach is implemented, in particular

A novel "gain chip" concept for high-power lasers (Conference Presentation)

NASA Astrophysics Data System (ADS)

Li, Min; Li, Mingzhong; Wang, Zhenguo; Yan, Xiongwei; Jiang, Xinying; Zheng, Jiangang; Cui, Xudong; Zhang, Xiaomin

2017-05-01

High-power lasers, including high-peak power lasers (HPPL) and high-average power lasers (HAPL), attract much interest for enormous variety of applications in inertial fusion energy (IFE), materials processing, defense, spectroscopy, and high-field physics research. To meet the requirements of high efficiency and quality, a "gain chip" concept is proposed to properly design the pumping, cooling and lasing fields. The gain chip mainly consists of the laser diode arrays, lens duct, rectangle wave guide and slab-shaped gain media. For the pumping field, the pump light will be compressed and homogenized by the lens duct to high irradiance with total internal reflection, and further coupled into the gain media through its two edge faces. For the cooling field, the coolant travels along the flow channel created by the adjacent slabs in the other two edge-face direction, and cool the lateral faces of the gain media. For the lasing field, the laser beam travels through the lateral faces and experiences minimum thermal wavefront distortions. Thereby, these three fields are in orthogonality offering more spatial freedom to handle them during the construction of the lasers. Transverse gradient doping profiles for HPPL and HAPL have been employed to achieve uniform gain distributions (UGD) within the gain media, respectively. This UGD will improve the management for both amplified spontaneous emission (ASE) and thermal behavior. Since each "gain chip" has its own pump source, power scaling can be easily achieved by placing identical "gain chips" along the laser beam axis without disturbing the gain and thermal distributions. To detail our concept, a 1-kJ pulsed amplifier is designed and optical-to-optical efficiency up to 40% has been obtained. We believe that with proper coolant (gas or liquid) and gain media (Yb:YAG, Nd:glass or Nd:YAG) our "gain chip" concept might provide a general configuration for high-power lasers with high efficiency and quality.

High-power and highly efficient diode-cladding-pumped holmium-doped fluoride fiber laser operating at 2.94 microm.

PubMed

Jackson, Stuart D

2009-08-01

A high-power diode-cladding-pumped Ho(3+), Pr(3+)-doped fluoride glass fiber laser is demonstrated. The laser produced a maximum output power of 2.5 W at a slope efficiency of 32% using diode lasers emitting at 1,150 nm. The long-emission wavelength of 2.94 microm measured at maximum pump power, which is particularly suited to medical applications, indicates that tailoring of the proportion of Pr(3+) ions can provide specific emission wavelengths while providing sufficient de-excitation of the lower laser level.

Fusion for Space Propulsion

NASA Technical Reports Server (NTRS)

Thio, Y. C. Francis; Schafer, Charles (Technical Monitor)

2001-01-01

There is little doubt that humans will attempt to explore and develop the solar system in this century. A large amount of energy will be required for accomplishing this. The need for fusion propulsion is discussed. For a propulsion system, there are three important thermodynamical attributes: (1) The absolute amount of energy available, (2) the propellant exhaust velocity, and (3) the jet power per unit mass of the propulsion system (specific power). For human exploration and development of the solar system, propellant exhaust velocity in excess of 100 km/s and specific power in excess of 10 kW/kg are required. Chemical combustion can produce exhaust velocity up to about 5 km/s. Nuclear fission processes typically result in producing energy in the form of heat that needs to be manipulated at temperatures limited by materials to about 2,800 K. Using the energy to heat a hydrogen propellant increases the exhaust velocity by only a factor of about two. Alternatively the energy can be converted into electricity which is then used to accelerate particles to high exhaust velocity. The necessary power conversion and conditioning equipment, however, increases the mass of the propulsion system for the same jet power by more than two orders of magnitude over chemical system, thus greatly limits the thrust-to-weight ratio attainable. The principal advantage of the fission process is that its development is relatively mature and is available right now. If fusion can be developed, fusion appears to have the best of all worlds in terms of propulsion - it can provide the absolute amount, the propellant exhaust velocity, and the high specific jet power. An intermediate step towards pure fusion propulsion is a bimodal system in which a fission reactor is used to provide some of the energy to drive a fusion propulsion unit. The technical issues related to fusion for space propulsion are discussed. The technical priorities for developing and applying fusion for propulsion are

Ultra Clean 1.1MW High Efficiency Natural Gas Engine Powered System

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zurlo, James; Lueck, Steve

Dresser, Inc. (GE Energy, Waukesha gas engines) will develop, test, demonstrate, and commercialize a 1.1 Megawatt (MW) natural gas fueled combined heat and power reciprocating engine powered package. This package will feature a total efficiency > 75% and ultra low CARB permitting emissions. Our modular design will cover the 1 – 6 MW size range, and this scalable technology can be used in both smaller and larger engine powered CHP packages. To further advance one of the key advantages of reciprocating engines, the engine, generator and CHP package will be optimized for low initial and operating costs. Dresser, Inc. willmore » leverage the knowledge gained in the DOE - ARES program. Dresser, Inc. will work with commercial, regulatory, and government entities to help break down barriers to wider deployment of CHP. The outcome of this project will be a commercially successful 1.1 MW CHP package with high electrical and total efficiency that will significantly reduce emissions compared to the current central power plant paradigm. Principal objectives by phases for Budget Period 1 include: • Phase 1 – market study to determine optimum system performance, target first cost, lifecycle cost, and creation of a detailed product specification. • Phase 2 – Refinement of the Waukesha CHP system design concepts, identification of critical characteristics, initial evaluation of technical solutions, and risk mitigation plans. Background« less

Generating High-Brightness Ion Beams for Inertial Confinement Fusion

NASA Astrophysics Data System (ADS)

Cuneo, M. E.

1997-11-01

The generation of high current density ion beams with applied-B ion diodes showed promise in the late-1980's as an efficient, rep-rate, focusable driver for inertial confinement fusion. These devices use several Tesla insulating magnetic fields to restrict electron motion across anode-cathode gaps of order 1-2 cm, while accelerating ions to generate ≈ 1 kA/cm^2, 5 - 15 MeV beams. These beams have been used to heat hohlraums to about 65 eV. However, meeting the ICF driver requirements for low-divergence and high-brightness lithium ion beams has been more technically challenging than initially thought. Experimental and theoretical work over the last 5 years shows that high-brightness beams meeting the requirements for inertial confinement fusion are possible. The production of these beams requires the simultaneous integration of at least four conditions: 1) rigorous vacuum cleaning techniques for control of undesired anode, cathode, ion source and limiter plasma formation from electrode contaminants to control impurity ions and impedance collapse; 2) carefully tailored insulating magnetic field geometry for uniform beam generation; 3) high magnetic fields (V_crit/V > 2) and other techniques to control the electron sheath and the onset of a high divergence electromagnetic instability that couples strongly to the ion beam; and 4) an active, pre-formed, uniform lithium plasma for low source divergence which is compatible with the above electron-sheath control techniques. These four conditions have never been simultaneously present in any lithium beam experiment, but simulations and experimental tests of individual conditions have been done. The integration of these conditions is a goal of the present ion beam generation program at Sandia. This talk will focus on the vacuum cleaning techniques for ion diodes and pulsed power devices in general, including experimental results obtained on the SABRE and PBFA-II accelerators over the last 3 years. The current status of

A review on applications of magnetoelectric composites: from heterostructural uncooled magnetic sensors, energy harvesters to highly efficient power converters

NASA Astrophysics Data System (ADS)

Leung, Chung Ming; Li, Jiefang; Viehland, D.; Zhuang, X.

2018-07-01

Over the past two decades, magnetoelectric (ME) composites and their devices have been an important topic of research. Potential applications ranging from low-power sensing to high-power converters have been investigated. This review, first begins with a summary of multiferroic materials that work at room temperature. Such ME materials are usually in composites, and their ME effect generated as a product property of magnetostrictive and piezoelectric composite layers. After that, mechanisms, working principles, and applications of ME composites from heterostructural uncooled magnetic sensors, energy harvesters to highly efficient power converters will be discussed. First, the development of ME sensors in terms of materials and structures to enhance their sensitivities and to reduce noise level is reviewed and discussed. Second, the structure of ME-based energy harvesters is discussed and summarized. Third, the development of ME gyrators is summarized for power applications, including current/voltage conversion, power efficiency, power density and figures of merit. Results demonstrate that our ME gyrator has the ability to satisfy the needs of power conversion with superior efficiency (>90%), offering potential uses in power electronic applications.

High Power and Efficiency Space Traveling-Wave Tube Amplifiers With Reduced Size and Mass for NASA Missions

NASA Technical Reports Server (NTRS)

Simons, Rainee N.; Wilson, Jeffrey D.; Force, Dale A.

2008-01-01

Recent advances in high power and efficiency space traveling-wave tube amplifiers (TWTAs) for NASA s space-to-Earth communications are presented in this paper. The RF power and efficiency of a new K-Band amplifier are 40 W and 50 percent and that of a new Ka-Band amplifier are 200 W and 60 percent. An important figure-of-merit, which is defined as the ratio of the RF power output to the mass (W/kg) of a TWT has improved by a factor of ten over the previous generation Ka-Band devices.

Evaluation of performance of select fusion experiments and projected reactors

NASA Technical Reports Server (NTRS)

Miley, G. H.

1978-01-01

The performance of NASA Lewis fusion experiments (SUMMA and Bumpy Torus) is compared with other experiments and that necessary for a power reactor. Key parameters cited are gain (fusion power/input power) and the time average fusion power, both of which may be more significant for real fusion reactors than the commonly used Lawson parameter. The NASA devices are over 10 orders of magnitude below the required powerplant values in both gain and time average power. The best experiments elsewhere are also as much as 4 to 5 orders of magnitude low. However, the NASA experiments compare favorably with other alternate approaches that have received less funding than the mainline experiments. The steady-state character and efficiency of plasma heating are strong advantages of the NASA approach. The problem, though, is to move ahead to experiments of sufficient size to advance in gain and average power parameters.

Fusion energy for space missions in the 21st Century

NASA Technical Reports Server (NTRS)

Schulze, Norman R.

1991-01-01

Future space missions were hypothesized and analyzed and the energy source for their accomplishment investigated. The mission included manned Mars, scientific outposts to and robotic sample return missions from the outer planets and asteroids, as well as fly-by and rendezvous mission with the Oort Cloud and the nearest star, Alpha Centauri. Space system parametric requirements and operational features were established. The energy means for accomplishing the High Energy Space Mission were investigated. Potential energy options which could provide the propulsion and electric power system and operational requirements were reviewed and evaluated. Fusion energy was considered to be the preferred option and was analyzed in depth. Candidate fusion fuels were evaluated based upon the energy output and neutron flux. Reactors exhibiting a highly efficient use of magnetic fields for space use while at the same time offering efficient coupling to an exhaust propellant or to a direct energy convertor for efficient electrical production were examined. Near term approaches were identified.

High efficiency laser-pumped emerald lasers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lai, S.T.

1987-09-25

Highly efficient laser operation has been achieved in emerald. In a quasi-cw laser-pumped emerald laser, 64% output slope efficiency has been measured at 768 nm, corresponding to a laser quantum yield of 76%. An output power of 1.6 W was reached at 3.6 W of pump power at 647.1 nm from a krypton laser, and was pump power limited. The emerald laser has a tuning range of 720 to 842 nm. The round trip loss excluding the excited state absorption (ESA) is 0.4%/cm. These results indicate the high laser efficiency and the high optical quality of the emerald attainable inmore » the present laser.« less

High-efficiency power production from natural gas with carbon capture

NASA Astrophysics Data System (ADS)

Adams, Thomas A.; Barton, Paul I.

A unique electricity generation process uses natural gas and solid oxide fuel cells at high electrical efficiency (74%HHV) and zero atmospheric emissions. The process contains a steam reformer heat-integrated with the fuel cells to provide the heat necessary for reforming. The fuel cells are powered with H 2 and avoid carbon deposition issues. 100% CO 2 capture is achieved downstream of the fuel cells with very little energy penalty using a multi-stage flash cascade process, where high-purity water is produced as a side product. Alternative reforming techniques such as CO 2 reforming, autothermal reforming, and partial oxidation are considered. The capital and energy costs of the proposed process are considered to determine the levelized cost of electricity, which is low when compared to other similar carbon capture-enabled processes.

High power gas laser - Applications and future developments

NASA Technical Reports Server (NTRS)

Hertzberg, A.

1977-01-01

Fast flow can be used to create the population inversion required for lasing action, or can be used to improve laser operation, for example by the removal of waste heat. It is pointed out that at the present time all lasers which are capable of continuous high-average power employ flow as an indispensable aspect of operation. High power laser systems are discussed, taking into account the gasdynamic laser, the HF supersonic diffusion laser, and electric discharge lasers. Aerodynamics and high power lasers are considered, giving attention to flow effects in high-power gas lasers, aerodynamic windows and beam manipulation, and the Venus machine. Applications of high-power laser technology reported are related to laser material working, the employment of the laser in controlled fusion machines, laser isotope separation and photochemistry, and laser power transmission.

Fusion Energy and Stopping Power in a Degenerate DT Pellet Driven by a Laser-Accelerated Proton Beam

NASA Astrophysics Data System (ADS)

Mehrangiz, M.; Ghasemizad, A.; Jafari, S.; Khanbabaei, B.

2016-06-01

In this paper, we have improved the fast ignition scheme in order to have more authority needed for high-energy-gain. Due to the more penetrability and energy deposition of the particle beams in fusion targets, we employ a laser-to-ion converter foil as a scheme for generating energetic ion beams to ignite the fusion fuel. We find the favorable intensity and wavelength of incident laser by evaluating the laser-proton conversion gain. By calculating the source-target distance, proton beam power and energy are estimated. Our analysis is generalized to the plasma degeneracy effects which can increase the fusion gain several orders of magnitude by decreasing the ion-electron collisions in the plasma. It is found that the wavelength of 0.53 μm and the intensity of about 1020 W/cm2, by saving about 10% conversion coefficient, are the suitable measured values for converting a laser into protons. Besides, stopping power and fusion burn calculations have been done in degenerate and non-degenerate plasma mediums. The results indicate that in the presence of degeneracy, the rate of fusion enhances. Supported by the Research Council of University of Guilan

Magnetized target fusion: An ultra high energy approach in an unexplored parameter space

NASA Astrophysics Data System (ADS)

Lindemuth, I. R.

Magnetized target fusion is a concept that may lead to practical fusion applications in a variety of settings. However, the crucial first step is to demonstrate that it works as advertised. Among the possibilities for doing this is an ultrahigh energy approach to magnetized target fusion, one powered by explosive pulsed power generators that have become available for application to thermonuclear fusion research. In a collaborative effort between Los Alamos and the All-Russian Scientific Institute for Experimental Physics (VNIIEF) a very powerful helical generator with explosive power switching has been used to produce an energetic magnetized plasma. Several diagnostics have been fielded to ascertain the properties of this plasma. We are intensively studying the results of the experiments and calculationally analyzing the performance of this experiment.

Optimization of the SHX Fusion Powered Transatmospheric Propulsion Concept

NASA Technical Reports Server (NTRS)

Adams, Robert B.; Landrum, D. Brian

2001-01-01

Existing propulsion technology has not achieved cost effective payload delivery rates to low earth orbit. A fusion based propulsion system, denoted as the Simultaneous Heating and eXpansion (SHX) engine, has been proposed in earlier papers. The SHX couples energy generated by a fusion reactor to the engine flowpath by use of coherent beam emitters. A quasi-one-dimensional flow model was used to quantify the effects of area expansion and energy input on propulsive efficiency for several beam models. Entropy calculations were included to evaluate the lost work in the system.

The challenge of developing structural materials for fusion power systems

NASA Astrophysics Data System (ADS)

Bloom, Everett E.

1998-10-01

Nuclear fusion can be one of the most attractive sources of energy from the viewpoint of safety and minimal environmental impact. Central in the goal of designing a safe, environmentally benign, and economically competitive fusion power system is the requirement for high performance, low activation materials. The general performance requirements for such materials have been defined and it is clear that materials developed for other applications (e.g. aerospace, nuclear fission, fossil energy systems) will not fully meet the needs of fusion. Advanced materials, with composition and microstructure tailored to yield properties that will satisfy the specific requirements of fusion must be developed. The international fusion programs have made significant progress towards this goal. Compositional requirements for low activation lead to a focus of development efforts on silicon carbide composites, vanadium alloys, and advanced martensitic steels as candidate structural material systems. Control of impurities will be critically important in actually achieving low activation but this appears possible. Neutron irradiation produces significant changes in the mechanical and physical properties of each of these material systems raising feasibility questions and design limitations. A focus of the research and development effort is to understand these effects, and through the development of specific compositions and microstructures, produce materials with improved and adequate performance. Other areas of research that are synergistic with the development of radiation resistant materials include fabrication, joining technology, chemical compatibility with coolants and tritium breeders and specific questions relating to the unique characteristics of a given material (e.g. coatings to reduce gas permeation in SiC composites) or design concept (e.g. electrical insulator coatings for liquid metal concepts).

Development of an efficient DC-DC SEPIC converter using wide bandgap power devices for high step-up applications

NASA Astrophysics Data System (ADS)

Al-bayati, Ali M. S.; Alharbi, Salah S.; Alharbi, Saleh S.; Matin, Mohammad

2017-08-01

A highly efficient high step-up dc-dc converter is the major requirement in the integration of low voltage renewable energy sources, such as photovoltaic panel module and fuel cell stacks, with a load or utility. This paper presents the development of an efficient dc-dc single-ended primary-inductor converter (SEPIC) for high step-up applications. Three SEPIC converters are designed and studied using different combinations of power devices: a combination based on all Si power devices using a Si-MOSFET and a Si-diode and termed as Si/Si, a combination based on a hybrid of Si and SiC power devices using the Si-MOSFET and a SiC-Schottky diode and termed as Si/SiC, and a combination based on all SiC power devices using a SiC-MOSFET and the SiC-Schottky diode and termed as SiC/SiC. The switching behavior of the Si-MOSFET and SiC-MOSFET is characterized and analyzed within the different combinations at the converter level. The effect of the diode type on the converter's overall performance is also discussed. The switching energy losses, total power losses, and the overall performance effciency of the converters are measured and reported under different switching frequencies. Furthermore, the potential of the designed converters to operate efficiently at a wide range of input voltages and output powers is studied. The analysis and results show an outstanding performance efficiency of the designed SiC/SiC based converter under a wide range of operating conditions.

Accelerators for Fusion Materials Testing

NASA Astrophysics Data System (ADS)

Knaster, Juan; Okumura, Yoshikazu

Fusion materials research is a worldwide endeavor as old as the parallel one working toward the long term stable confinement of ignited plasma. In a fusion reactor, the preservation of the required minimum thermomechanical properties of the in-vessel components exposed to the severe irradiation and heat flux conditions is an indispensable factor for safe operation; it is also an essential goal for the economic viability of fusion. Energy from fusion power will be extracted from the 14 MeV neutron freed as a product of the deuterium-tritium fusion reactions; thus, this kinetic energy must be absorbed and efficiently evacuated and electricity eventually generated by the conventional methods of a thermal power plant. Worldwide technological efforts to understand the degradation of materials exposed to 14 MeV neutron fluxes >1018 m-2s-1, as expected in future fusion power plants, have been intense over the last four decades. Existing neutron sources can reach suitable dpa (“displacement-per-atom”, the figure of merit to assess materials degradation from being exposed to neutron irradiation), but the differences in the neutron spectrum of fission reactors and spallation sources do not allow one to unravel the physics and to anticipate the degradation of materials exposed to fusion neutrons. Fusion irradiation conditions can be achieved through Li (d, xn) nuclear reactions with suitable deuteron beam current and energy, and an adequate flowing lithium screen. This idea triggered in the late 1970s at Los Alamos National Laboratory (LANL) a campaign working toward the feasibility of continuous wave (CW) high current linacs framed by the Fusion Materials Irradiation Test (FMIT) project. These efforts continued with the Low Energy Demonstrating Accelerator (LEDA) (a validating prototype of the canceled Accelerator Production of Tritium (APT) project), which was proposed in 2002 to the fusion community as a 6.7MeV, 100mA CW beam injector for a Li (d, xn) source to bridge

Accelerators for Fusion Materials Testing

NASA Astrophysics Data System (ADS)

Knaster, Juan; Okumura, Yoshikazu

Fusion materials research is a worldwide endeavor as old as the parallel one working toward the long term stable confinement of ignited plasma. In a fusion reactor, the preservation of the required minimum thermomechanical properties of the in-vessel components exposed to the severe irradiation and heat flux conditions is an indispensable factor for safe operation; it is also an essential goal for the economic viability of fusion. Energy from fusion power will be extracted from the 14 MeV neutron freed as a product of the deuterium-tritium fusion reactions; thus, this kinetic energy must be absorbed and efficiently evacuated and electricity eventually generated by the conventional methods of a thermal power plant. Worldwide technological efforts to understand the degradation of materials exposed to 14 MeV neutron fluxes > 1018 m-2s-1, as expected in future fusion power plants, have been intense over the last four decades. Existing neutron sources can reach suitable dpa ("displacement-per-atom", the figure of merit to assess materials degradation from being exposed to neutron irradiation), but the differences in the neutron spectrum of fission reactors and spallation sources do not allow one to unravel the physics and to anticipate the degradation of materials exposed to fusion neutrons. Fusion irradiation conditions can be achieved through Li (d, xn) nuclear reactions with suitable deuteron beam current and energy, and an adequate flowing lithium screen. This idea triggered in the late 1970s at Los Alamos National Laboratory (LANL) a campaign working toward the feasibility of continuous wave (CW) high current linacs framed by the Fusion Materials Irradiation Test (FMIT) project. These efforts continued with the Low Energy Demonstrating Accelerator (LEDA) (a validating prototype of the canceled Accelerator Production of Tritium (APT) project), which was proposed in 2002 to the fusion community as a 6.7MeV, 100mA CW beam injector for a Li (d, xn) source to bridge

High efficiency 4H-SiC betavoltaic power sources using tritium radioisotopes

NASA Astrophysics Data System (ADS)

Thomas, Christopher; Portnoff, Samuel; Spencer, M. G.

2016-01-01

Realization of an 18.6% efficient 4H-silicon carbide (4H-SiC) large area betavoltaic power source using the radioisotope tritium is reported. A 200 nm 4H-SiC P+N junction is used to collect high-energy electrons. The electron source is a titanium tritide (TiH3x) foil, or an integrated titanium tritide region formed by the diffusion of tritium into titanium. The specific activity of the source is directly measured. Dark current measured under short circuit conditions was less than 6.1 pA/cm2. Samples measured with an external tritium foil produced an open circuit voltage of 2.09 V, short circuit current of 75.47 nA/cm2, fill factor of 0.86, and power efficiency of 18.6%. Samples measured with an integrated source produced power efficiencies of 12%. Simulations were done to determine the beta spectrum (modified by self absorption) exiting the source and the electron hole pair generation function in the 4H-SiC. The electron-hole pair generation function in 4H-SiC was modeled as a Gaussian distribution, and a closed form solution of the continuity equation was used to analyze the cell performance. The effective surface recombination velocity in our samples was found to be 105-106 cm/s. Our analysis demonstrated that the surface recombination dominates the performance of a tritium betavoltaic device but that using a thin P+N junction structure can mitigate some of the negative effects.

Magnetized Target Fusion: Prospects for Low-Cost Fusion Energy

NASA Technical Reports Server (NTRS)

Siemon, Richard E.; Turchi, Peter J.; Barnes, Daniel C.; Degnan, James; Parks, Paul; Ryutov, Dmitri D.; Thio, Y. C. Francis; Schafer, Charles (Technical Monitor)

2001-01-01

Magnetized Target Fusion (MTF) has attracted renewed interest in recent years because it has the potential to resolve one of the major problems with conventional fusion energy research - the high cost of facilities to do experiments and in general develop practical fusion energy. The requirement for costly facilities can be traced to fundamental constraints. The Lawson condition implies large system size in the case of conventional magnetic confinement, or large heating power in the case of conventional inertial confinement. The MTF approach is to use much higher fuel density than with conventional magnetic confinement (corresponding to megabar pressures), which results in a much-reduced system size to achieve Lawson conditions. Intrinsically the system must be pulsed because the pressures exceed the strength of any known material. To facilitate heating the fuel (or "target") to thermonuclear conditions with a high-power high-intensity source of energy, magnetic fields are used to insulate the high-pressure fuel from material surroundings (thus "magnetized target"). Because of magnetic insulation, the required heating power intensity is reduced by many orders of magnitude compared to conventional inertial fusion, even with relatively poor energy confinement in the magnetic field, such as that characterized by Bohm diffusion. In this paper we show semi-quantitatively why MTF-should allow fusion energy production without costly facilities within the same generally accepted physical constraints used for conventional magnetic and inertial fusion. We also briefly discuss potential applications of this technology ranging from nuclear rockets for space propulsion to a practical commercial energy system. Finally, we report on the exploratory research underway, and the interesting physics issues that arise in the MTF regime of parameters. Experiments at Los Alamos are focused on formation of a suitable plasma target for compression, utilizing the knowledge base for compact

Power efficient optical communications for space applications

NASA Technical Reports Server (NTRS)

Lesh, J. R.

1982-01-01

Optical communications technology promises substantial size, weight and power consumption savings for space to space high data rate communications over presently used microwave technology. These benefits are further increased by making the most efficient use of the available optical signal energy. This presentation will describe the progress to date on a project to design, build and demonstrate in the laboratory an optical communication system capable of conveying 2.5 bits of information per effective received photon. Such high power efficiencies will reduce the need for photon collection at the receiver and will greatly reduce the requirements for optical pointing accuracy, both at the transmitter as well as the receiver. A longer range program to demonstrate even higher photon efficiencies will also be described.

Laser or charged-particle-beam fusion reactor with direct electric generation by magnetic flux compression

DOEpatents

Lasche, George P.

1988-01-01

A high-power-density laser or charged-particle-beam fusion reactor system maximizes the directed kinetic energy imparted to a large mass of liquid lithium by a centrally located fusion target. A fusion target is embedded in a large mass of lithium, of sufficient radius to act as a tritium breeding blanket, and provided with ports for the access of beam energy to implode the target. The directed kinetic energy is converted directly to electricity with high efficiency by work done against a pulsed magnetic field applied exterior to the lithium. Because the system maximizes the blanket thickness per unit volume of lithium, neutron-induced radioactivities in the reaction chamber wall are several orders of magnitude less than is typical of other fusion reactor systems.

Laser or charged-particle-beam fusion reactor with direct electric generation by magnetic flux compression

DOEpatents

Lasche, G.P.

1987-02-20

A high-power-density-laser or charged-particle-beam fusion reactor system maximizes the directed kinetic energy imparted to a large mass of liquid lithium by a centrally located fusion target. A fusion target is embedded in a large mass of lithium, of sufficient radius to act as a tritium breeding blanket, and provided with ports for the access of beam energy to implode the target. The directed kinetic energy is converted directly to electricity with high efficiency by work done against a pulsed magnetic field applied exterior to the lithium. Because the system maximizes the blanket thickness per unit volume of lithium, neutron-induced radioactivities in the reaction chamber wall are several orders of magnitude less than is typical of other fusion reactor systems. 25 figs.

Medium Bandgap Conjugated Polymer for High Performance Polymer Solar Cells Exceeding 9% Power Conversion Efficiency.

PubMed

Jung, Jae Woong; Liu, Feng; Russell, Thomas P; Jo, Won Ho

2015-12-02

Two medium-bandgap polymers composed of benzo[1,2-b:4,5-b']dithiohpene and 2,1,3-benzothiadiazole with 6-octyl-thieno[3,2-b]thiophene as a π-bridge unit are synthesized and their photovoltaic properties are analyzed. The two polymers have deep highest occupied molecular orbital energy levels, high crystallinity, optimal bulk-heterojunction morphology, and efficient charge transport, resulting in a power conversion efficiency of as high as 9.44% for a single-junction polymer solar-cell device. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Developmental validation of the PowerPlex(®) Fusion 6C System.

PubMed

Ensenberger, Martin G; Lenz, Kristy A; Matthies, Learden K; Hadinoto, Gregory M; Schienman, John E; Przech, Angela J; Morganti, Michael W; Renstrom, Daniel T; Baker, Victoria M; Gawrys, Kori M; Hoogendoorn, Marlijn; Steffen, Carolyn R; Martín, Pablo; Alonso, Antonio; Olson, Hope R; Sprecher, Cynthia J; Storts, Douglas R

2016-03-01

The PowerPlex(®) Fusion 6C System is a 27-locus, six-dye, multiplex that includes all markers in the expanded CODIS core loci and increases overlap with STR database standards throughout the world. Additionally, it contains two, rapidly mutating, Y-STRs and is capable of both casework and database workflows, including direct amplification. A multi-laboratory developmental validation study was performed on the PowerPlex(®) Fusion 6C System. Here, we report the results of that study which followed SWGDAM guidelines and includes data for: species specificity, sensitivity, stability, precision, reproducibility and repeatability, case-type samples, concordance, stutter, DNA mixtures, and PCR-based procedures. Where appropriate we report data from both extracted DNA samples and direct amplification samples from various substrates and collection devices. Samples from all studies were separated on both Applied Biosystems 3500 series and 6-dye capable 3130 series Genetic Analyzers and data is reported for each. Together, the data validate the design and demonstrate the performance of the PowerPlex(®) Fusion 6C System. Copyright © 2015 The Authors. Published by Elsevier Ireland Ltd.. All rights reserved.

Spatial filter with volume gratings for high-peak-power multistage laser amplifiers

NASA Astrophysics Data System (ADS)

Tan, Yi-zhou; Yang, Yi-sheng; Zheng, Guang-wei; Shen, Ben-jian; Pan, Heng-yue; Liu, Li

2010-08-01

The regular spatial filters comprised of lens and pinhole are essential component in high power laser systems, such as lasers for inertial confinement fusion, nonlinear optical technology and directed-energy weapon. On the other hand the pinhole is treated as a bottleneck of high power laser due to harmful plasma created by the focusing beam. In this paper we present a spatial filter based on angular selectivity of Bragg diffraction grating to avoid the harmful focusing effect in the traditional pinhole filter. A spatial filter consisted of volume phase gratings in two-pass amplifier cavity were reported. Two-dimensional filter was proposed by using single Pi-phase-shifted Bragg grating, numerical simulation results shown that its angular spectrum bandwidth can be less than 160urad. The angular selectivity of photo-thermorefractive glass and RUGATE film filters, construction stability, thermal stability and the effects of misalignments of gratings on the diffraction efficiencies under high-pulse-energy laser operating condition are discussed.

Multiple beam induction accelerators for heavy ion fusion

NASA Astrophysics Data System (ADS)

Seidl, Peter A.; Barnard, John J.; Faltens, Andris; Friedman, Alex; Waldron, William L.

2014-01-01

Induction accelerators are appealing for heavy-ion driven inertial fusion energy (HIF) because of their high efficiency and their demonstrated capability to accelerate high beam current (≥10 kA in some applications). For the HIF application, accomplishments and challenges are summarized. HIF research and development has demonstrated the production of single ion beams with the required emittance, current, and energy suitable for injection into an induction linear accelerator. Driver scale beams have been transported in quadrupole channels of the order of 10% of the number of quadrupoles of a driver. We review the design and operation of induction accelerators and the relevant aspects of their use as drivers for HIF. We describe intermediate research steps that would provide the basis for a heavy-ion research facility capable of heating matter to fusion relevant temperatures and densities, and also to test and demonstrate an accelerator architecture that scales well to a fusion power plant.

BInGaN alloys nearly lattice-matched to GaN for high-power high-efficiency visible LEDs

NASA Astrophysics Data System (ADS)

Williams, Logan; Kioupakis, Emmanouil

2017-11-01

InGaN-based visible light-emitting diodes (LEDs) find commercial applications for solid-state lighting and displays, but lattice mismatch limits the thickness of InGaN quantum wells that can be grown on GaN with high crystalline quality. Since narrower wells operate at a higher carrier density for a given current density, they increase the fraction of carriers lost to Auger recombination and lower the efficiency. The incorporation of boron, a smaller group-III element, into InGaN alloys is a promising method to eliminate the lattice mismatch and realize high-power, high-efficiency visible LEDs with thick active regions. In this work, we apply predictive calculations based on hybrid density functional theory to investigate the thermodynamic, structural, and electronic properties of BInGaN alloys. Our results show that BInGaN alloys with a B:In ratio of 2:3 are better lattice matched to GaN compared to InGaN and, for indium fractions less than 0.2, nearly lattice matched. Deviations from Vegard's law appear as bowing of the in-plane lattice constant with respect to composition. Our thermodynamics calculations demonstrate that the solubility of boron is higher in InGaN than in pure GaN. Varying the Ga mole fraction while keeping the B:In ratio constant enables the adjustment of the (direct) gap in the 1.75-3.39 eV range, which covers the entire visible spectrum. Holes are strongly localized in non-bonded N 2p states caused by local bond planarization near boron atoms. Our results indicate that BInGaN alloys are promising for fabricating nitride heterostructures with thick active regions for high-power, high-efficiency LEDs.

Combined Heat and Power Systems Technology Development and Demonstration 370 kW High Efficiency Microturbine

DOE Office of Scientific and Technical Information (OSTI.GOV)

none,

The C370 Program was awarded in October 2010 with the ambitious goal of designing and testing the most electrically efficient recuperated microturbine engine at a rated power of less than 500 kW. The aggressive targets for electrical efficiency, emission regulatory compliance, and the estimated price point make the system state-of-the-art for microturbine engine systems. These goals will be met by designing a two stage microturbine engine identified as the low pressure spool and high pressure spool that are based on derivative hardware of Capstone’s current commercially available engines. The development and testing of the engine occurred in two phases. Phasemore » I focused on developing a higher power and more efficient engine, that would become the low pressure spool which is based on Capstone’s C200 (200kW) engine architecture. Phase II integrated the low pressure spool created in Phase I with the high pressure spool, which is based on Capstone’s C65 (65 kW) commercially available engine. Integration of the engines, based on preliminary research, would allow the dual spool engine to provide electrical power in excess of 370 kW, with electrical efficiency approaching 42%. If both of these targets were met coupled with the overall CHP target of 85% total combined heating and electrical efficiency California Air Resources Board (CARB) level emissions, and a price target of $600 per kW, the system would represent a step change in the currently available commercial generation technology. Phase I of the C370 program required the development of the C370 low pressure spool. The goal was to increase the C200 engine power by a minimum of 25% — 250 kW — and efficiency from 32% to 37%. These increases in the C200 engine output were imperative to meet the power requirements of the engine when both spools were integrated. An additional benefit of designing and testing the C370 low pressure spool was the possibility of developing a stand-alone product for possible

Numerical Design of Megawatt Gyrotron with 120 GHz Frequency and 50% Efficiency for Plasma Fusion Application

NASA Astrophysics Data System (ADS)

Kumar, Nitin; Singh, Udaybir; Kumar, Anil; Bhattacharya, Ranajoy; Singh, T. P.; Sinha, A. K.

2013-02-01

The design of 120 GHz, 1 MW gyrotron for plasma fusion application is presented in this paper. The mode selection is carried out considering the aim of minimum mode competition, minimum cavity wall heating, etc. On the basis of the selected operating mode, the interaction cavity design and beam-wave interaction computation are carried out by using the PIC code. The design of triode type Magnetron Injection Gun (MIG) is also presented. Trajectory code EGUN, synthesis code MIGSYN and data analysis code MIGANS are used in the MIG designing. Further, the design of MIG is also validated by using the another trajectory code TRAK. The design results of beam dumping system (collector) and RF window are also presented. Depressed collector is designed to enhance the overall tube efficiency. The design study confirms >1 MW output power with tube efficiency around 50% (with collector efficiency).

Solution-Processed Phosphorescent Organic Light-Emitting Diodes with Ultralow Driving Voltage and Very High Power Efficiency

NASA Astrophysics Data System (ADS)

Wang, Shumeng; Wang, Xingdong; Yao, Bing; Zhang, Baohua; Ding, Junqiao; Xie, Zhiyuan; Wang, Lixiang

2015-07-01

To realize power efficient solution-processed phosphorescent organic light-emitting diodes (s-PhOLEDs), the corresponding high driving voltage issue should be well solved. To solve it, efforts have been devoted to the exploitation of novel host or interfacial materials. However, the issues of charge trapping of phosphor and/or charge injection barrier are still serious, largely restraining the power efficiency (PE) levels. Herein, with the utilization of an exciplex-forming couple 4, 4‧, 4″ -tris[3-methylphenyl(phenyl)amino]triphenylamine (m-MTDATA) and 1,3,5-tri(m-pyrid-3-yl-phenyl)benzene (TmPyPB), the efficient charge injection and transporting, barrier-free hole-electron recombination for the formation of the interfacial exciplex, and elimination of charge traps of phosphors in the emissive layer are realized simultaneously, resulting in a turn-on voltage of 2.36 V, a record high PE of 97.2 lm W-1, as well as extremely low driving voltage of 2.60 V at 100 cd m-2, 3.03 V at 1000 cd m-2 and 4.08 V at 10000 cd m-2. This report is the first time that the PE performance of s-PhOLED approaches 100 lm W-1 high level, even superior to the corresponding state-of-the-art performance of the same color vacuum-deposited PhOLED (v-PhOLED) counterpart. We anticipate this report opens a new avenue for achieving power efficient monochromatic and white s-PhOLEDs with simple structures.

Solution-Processed Phosphorescent Organic Light-Emitting Diodes with Ultralow Driving Voltage and Very High Power Efficiency

PubMed Central

Wang, Shumeng; Wang, Xingdong; Yao, Bing; Zhang, Baohua; Ding, Junqiao; Xie, Zhiyuan; Wang, Lixiang

2015-01-01

To realize power efficient solution-processed phosphorescent organic light-emitting diodes (s-PhOLEDs), the corresponding high driving voltage issue should be well solved. To solve it, efforts have been devoted to the exploitation of novel host or interfacial materials. However, the issues of charge trapping of phosphor and/or charge injection barrier are still serious, largely restraining the power efficiency (PE) levels. Herein, with the utilization of an exciplex-forming couple 4, 4′, 4″ -tris[3-methylphenyl(phenyl)amino]triphenylamine (m-MTDATA) and 1,3,5-tri(m-pyrid-3-yl-phenyl)benzene (TmPyPB), the efficient charge injection and transporting, barrier-free hole-electron recombination for the formation of the interfacial exciplex, and elimination of charge traps of phosphors in the emissive layer are realized simultaneously, resulting in a turn-on voltage of 2.36 V, a record high PE of 97.2 lm W−1, as well as extremely low driving voltage of 2.60 V at 100 cd m−2, 3.03 V at 1000 cd m−2 and 4.08 V at 10000 cd m−2. This report is the first time that the PE performance of s-PhOLED approaches 100 lm W−1 high level, even superior to the corresponding state-of-the-art performance of the same color vacuum-deposited PhOLED (v-PhOLED) counterpart. We anticipate this report opens a new avenue for achieving power efficient monochromatic and white s-PhOLEDs with simple structures. PMID:26204810

Solution-Processed Phosphorescent Organic Light-Emitting Diodes with Ultralow Driving Voltage and Very High Power Efficiency.

PubMed

Wang, Shumeng; Wang, Xingdong; Yao, Bing; Zhang, Baohua; Ding, Junqiao; Xie, Zhiyuan; Wang, Lixiang

2015-07-24

To realize power efficient solution-processed phosphorescent organic light-emitting diodes (s-PhOLEDs), the corresponding high driving voltage issue should be well solved. To solve it, efforts have been devoted to the exploitation of novel host or interfacial materials. However, the issues of charge trapping of phosphor and/or charge injection barrier are still serious, largely restraining the power efficiency (PE) levels. Herein, with the utilization of an exciplex-forming couple 4, 4', 4″-tris[3-methylphenyl(phenyl)amino]triphenylamine (m-MTDATA) and 1,3,5-tri(m-pyrid-3-yl-phenyl)benzene (TmPyPB), the efficient charge injection and transporting, barrier-free hole-electron recombination for the formation of the interfacial exciplex, and elimination of charge traps of phosphors in the emissive layer are realized simultaneously, resulting in a turn-on voltage of 2.36 V, a record high PE of 97.2 lm W(-1), as well as extremely low driving voltage of 2.60 V at 100 cd m(-2), 3.03 V at 1000 cd m(-2) and 4.08 V at 10000 cd m(-2). This report is the first time that the PE performance of s-PhOLED approaches 100 lm W(-1) high level, even superior to the corresponding state-of-the-art performance of the same color vacuum-deposited PhOLED (v-PhOLED) counterpart. We anticipate this report opens a new avenue for achieving power efficient monochromatic and white s-PhOLEDs with simple structures.

High efficiency 4H-SiC betavoltaic power sources using tritium radioisotopes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Thomas, Christopher; Portnoff, Samuel; Spencer, M. G.

Realization of an 18.6% efficient 4H-silicon carbide (4H-SiC) large area betavoltaic power source using the radioisotope tritium is reported. A 200 nm 4H-SiC P{sup +}N junction is used to collect high-energy electrons. The electron source is a titanium tritide (TiH{sup 3}{sub x}) foil, or an integrated titanium tritide region formed by the diffusion of tritium into titanium. The specific activity of the source is directly measured. Dark current measured under short circuit conditions was less than 6.1 pA/cm{sup 2}. Samples measured with an external tritium foil produced an open circuit voltage of 2.09 V, short circuit current of 75.47 nA/cm{sup 2}, fill factor of 0.86,more » and power efficiency of 18.6%. Samples measured with an integrated source produced power efficiencies of 12%. Simulations were done to determine the beta spectrum (modified by self absorption) exiting the source and the electron hole pair generation function in the 4H-SiC. The electron-hole pair generation function in 4H-SiC was modeled as a Gaussian distribution, and a closed form solution of the continuity equation was used to analyze the cell performance. The effective surface recombination velocity in our samples was found to be 10{sup 5}–10{sup 6 }cm/s. Our analysis demonstrated that the surface recombination dominates the performance of a tritium betavoltaic device but that using a thin P{sup +}N junction structure can mitigate some of the negative effects.« less

High efficiency H6 single-phase transformerless grid-tied PV inverter with proposed modulation for reactive power generation

NASA Astrophysics Data System (ADS)

Almasoudi, Fahad M.; Alatawi, Khaled S.; Matin, Mohammad

2017-08-01

Implementation of transformerless inverters in PV grid-tied system offer great benefits such as high efficiency, light weight, low cost, etc. Most of the proposed transformerless inverters in literature are verified for only real power application. Currently, international standards such as VDE-AR-N 4105 has demanded that PV grid-tied inverters should have the ability of controlling a specific amount of reactive power. Generation of reactive power cannot be accomplished in single phase transformerless inverter topologies because the existing modulation techniques are not adopted for a freewheeling path in the negative power region. This paper enhances a previous high efficiency proposed H6 trnasformerless inverter with SiC MOSFETs and demonstrates new operating modes for the generation of reactive power. A proposed pulse width modulation (PWM) technique is applied to achieve bidirectional current flow through freewheeling state. A comparison of the proposed H6 transformerless inverter using SiC MOSFETs and Si MOSFTEs is presented in terms of power losses and efficiency. The results show that reactive power control is attained without adding any additional active devices or modification to the inverter structure. Also, the proposed modulation maintains a constant common mode voltage (CM) during every operating mode and has low leakage current. The performance of the proposed system verifies its effectiveness in the next generation PV system.

High-gain magnetized inertial fusion.

PubMed

Slutz, Stephen A; Vesey, Roger A

2012-01-13

Magnetized inertial fusion (MIF) could substantially ease the difficulty of reaching plasma conditions required for significant fusion yields, but it has been widely accepted that the gain is not sufficient for fusion energy. Numerical simulations are presented showing that high-gain MIF is possible in cylindrical liner implosions based on the MagLIF concept [S. A. Slutz et al Phys. Plasmas 17, 056303 (2010)] with the addition of a cryogenic layer of deuterium-tritium (DT). These simulations show that a burn wave propagates radially from the magnetized hot spot into the surrounding much denser cold DT given sufficient hot-spot areal density. For a drive current of 60 MA the simulated gain exceeds 100, which is more than adequate for fusion energy applications. The simulated gain exceeds 1000 for a drive current of 70 MA.

Shock ignition: a new approach to high gain inertial confinement fusion on the national ignition facility.

PubMed

Perkins, L J; Betti, R; LaFortune, K N; Williams, W H

2009-07-24

Shock ignition, an alternative concept for igniting thermonuclear fuel, is explored as a new approach to high gain, inertial confinement fusion targets for the National Ignition Facility (NIF). Results indicate thermonuclear yields of approximately 120-250 MJ may be possible with laser drive energies of 1-1.6 MJ, while gains of approximately 50 may still be achievable at only approximately 0.2 MJ drive energy. The scaling of NIF energy gain with laser energy is found to be G approximately 126E (MJ);{0.510}. This offers the potential for high-gain targets that may lead to smaller, more economic fusion power reactors and a cheaper fusion energy development path.

FusionAnalyser: a new graphical, event-driven tool for fusion rearrangements discovery

PubMed Central

Piazza, Rocco; Pirola, Alessandra; Spinelli, Roberta; Valletta, Simona; Redaelli, Sara; Magistroni, Vera; Gambacorti-Passerini, Carlo

2012-01-01

Gene fusions are common driver events in leukaemias and solid tumours; here we present FusionAnalyser, a tool dedicated to the identification of driver fusion rearrangements in human cancer through the analysis of paired-end high-throughput transcriptome sequencing data. We initially tested FusionAnalyser by using a set of in silico randomly generated sequencing data from 20 known human translocations occurring in cancer and subsequently using transcriptome data from three chronic and three acute myeloid leukaemia samples. in all the cases our tool was invariably able to detect the presence of the correct driver fusion event(s) with high specificity. In one of the acute myeloid leukaemia samples, FusionAnalyser identified a novel, cryptic, in-frame ETS2–ERG fusion. A fully event-driven graphical interface and a flexible filtering system allow complex analyses to be run in the absence of any a priori programming or scripting knowledge. Therefore, we propose FusionAnalyser as an efficient and robust graphical tool for the identification of functional rearrangements in the context of high-throughput transcriptome sequencing data. PMID:22570408

FusionAnalyser: a new graphical, event-driven tool for fusion rearrangements discovery.

PubMed

Piazza, Rocco; Pirola, Alessandra; Spinelli, Roberta; Valletta, Simona; Redaelli, Sara; Magistroni, Vera; Gambacorti-Passerini, Carlo

2012-09-01

Gene fusions are common driver events in leukaemias and solid tumours; here we present FusionAnalyser, a tool dedicated to the identification of driver fusion rearrangements in human cancer through the analysis of paired-end high-throughput transcriptome sequencing data. We initially tested FusionAnalyser by using a set of in silico randomly generated sequencing data from 20 known human translocations occurring in cancer and subsequently using transcriptome data from three chronic and three acute myeloid leukaemia samples. in all the cases our tool was invariably able to detect the presence of the correct driver fusion event(s) with high specificity. In one of the acute myeloid leukaemia samples, FusionAnalyser identified a novel, cryptic, in-frame ETS2-ERG fusion. A fully event-driven graphical interface and a flexible filtering system allow complex analyses to be run in the absence of any a priori programming or scripting knowledge. Therefore, we propose FusionAnalyser as an efficient and robust graphical tool for the identification of functional rearrangements in the context of high-throughput transcriptome sequencing data.

The VISTA spacecraft: Advantages of ICF (Inertial Confinement Fusion) for interplanetary fusions propulsion applications

NASA Technical Reports Server (NTRS)

Orth, Charles D.; Klein, Gail; Sercel, Joel; Hoffman, Nate; Murray, Kathy; Chang-Diaz, Franklin

1987-01-01

Inertial Confinement Fusion (ICF) is an attractive engine power source for interplanetary manned spacecraft, especially for near-term missions requiring minimum flight duration, because ICF has inherent high power-to-mass ratios and high specific impulses. We have developed a new vehicle concept called VISTA that uses ICF and is capable of round-trip manned missions to Mars in 100 days using A.D. 2020 technology. We describe VISTA's engine operation, discuss associated plasma issues, and describe the advantages of DT fuel for near-term applications. Although ICF is potentially superior to non-fusion technologies for near-term interplanetary transport, the performance capabilities of VISTA cannot be meaningfully compared with those of magnetic-fusion systems because of the lack of a comparable study of the magnetic-fusion systems. We urge that such a study be conducted.

Highly efficient solid state magnetoelectric gyrators

NASA Astrophysics Data System (ADS)

Leung, Chung Ming; Zhuang, Xin; Friedrichs, Daniel; Li, Jiefang; Erickson, Robert W.; Laletin, V.; Popov, M.; Srinivasan, G.; Viehland, D.

2017-09-01

An enhancement in the power-conversion-efficiency (η) of a magneto-electric (ME) gyrator has been found by the use of Mn-substituted nickel zinc ferrite. A trilayer gyrator of Mn-doped Ni0.8Zn0.2Fe2O3 and Pb(Zr,Ti)O3 has η = 85% at low power conditions (˜20 mW/in3) and η ≥ 80% at high power conditions (˜5 W/in3). It works close to fundamental electromechanical resonance in both direct and converse modes. The value of η is by far the highest reported so far, which is due to the high mechanical quality factor (Qm) of the magnetostrictive ferrite. Such highly efficient ME gyrators with a significant power density could become important elements in power electronics, potentially replacing electromagnetic and piezoelectric transformers.

High power microwave generator

DOEpatents

Ekdahl, Carl A.

1986-01-01

A microwave generator efficiently converts the energy of an intense relativistic electron beam (REB) into a high-power microwave emission using the Smith-Purcell effect which is related to Cerenkov radiation. Feedback for efficient beam bunching and high gain is obtained by placing a cylindrical Smith-Purcell transmission grating on the axis of a toroidal resonator. High efficiency results from the use of a thin cold annular highly-magnetized REB that is closely coupled to the resonant structure.

High power microwave generator

DOEpatents

Ekdahl, C.A.

1983-12-29

A microwave generator efficiently converts the energy of an intense relativistic electron beam (REB) into a high-power microwave emission using the Smith-Purcell effect which is related to Cerenkov radiation. Feedback for efficient beam bunching and high gain is obtained by placing a cylindrical Smith-Purcell transmission grating on the axis of a toroidal resonator. High efficiency results from the use of a thin cold annular highly-magnetized REB that is closely coupled to the resonant structure.

Design of high-efficiency Joule-Thomson cycles for high-temperature superconductor power cable cooling

NASA Astrophysics Data System (ADS)

Jin, Lingxue; Lee, Cheonkyu; Baek, Seungwhan; Jeong, Sangkwon

2018-07-01

Liquid nitrogen (LN2) is commonly used as the coolant of a high temperature superconductor (HTS) power cable. The LN2 is continuously cooled by a subcooler to maintain an appropriate operating temperature of the cable. This paper proposes two Joule-Thomson (JT) refrigeration cycles for subcooling the LN2 coolant by using nitrogen itself as the working fluid. Additionally, an innovative HTS cooling cycle, of which the cable coolant and the refrigerant are unified and supplied from the same source, is suggested and analyzed in detail. Among these cycles, the highest COP is obtained in the JT cycle with a vacuum pump (Cycle A) which is 0.115 at 78 K, and the Carnot efficiency is 32.8%. The integrated HTS cooling cycle (Cycle C) can reach the maximum COP of 0.087, and the Carnot efficiency of 24.8%. Although Cycle C has a relatively low cycle efficiency when compared to that of the separated refrigeration cycle, it can be a good alternative in engineering applications, because the assembled hardware has few machinery components in a more compact configuration than the other cycles.

An Integrated Power-Efficient Active Rectifier With Offset-Controlled High Speed Comparators for Inductively Powered Applications

PubMed Central

Lee, Hyung-Min; Ghovanloo, Maysam

2011-01-01

We present an active full-wave rectifier with offset-controlled high speed comparators in standard CMOS that provides high power conversion efficiency (PCE) in high frequency (HF) range for inductively powered devices. This rectifier provides much lower dropout voltage and far better PCE compared to the passive on-chip or off-chip rectifiers. The built-in offset-control functions in the comparators compensate for both turn-on and turn-off delays in the main rectifying switches, thus maximizing the forward current delivered to the load and minimizing the back current to improve the PCE. We have fabricated this active rectifier in a 0.5-μm 3M2P standard CMOS process, occupying 0.18 mm2 of chip area. With 3.8 V peak ac input at 13.56 MHz, the rectifier provides 3.12 V dc output to a 500 Ω load, resulting in the PCE of 80.2%, which is the highest measured at this frequency. In addition, overvoltage protection (OVP) as safety measure and built-in back telemetry capabilities have been incorporated in our design using detuning and load shift keying (LSK) techniques, respectively, and tested. PMID:22174666

High-Power, High-Thrust Ion Thruster (HPHTion)

NASA Technical Reports Server (NTRS)

Peterson, Peter Y.

2015-01-01

Advances in high-power photovoltaic technology have enabled the possibility of reasonably sized, high-specific power solar arrays. At high specific powers, power levels ranging from 50 to several hundred kilowatts are feasible. Ion thrusters offer long life and overall high efficiency (typically greater than 70 percent efficiency). In Phase I, the team at ElectroDynamic Applications, Inc., built a 25-kW, 50-cm ion thruster discharge chamber and fabricated a laboratory model. This was in response to the need for a single, high-powered engine to fill the gulf between the 7-kW NASA's Evolutionary Xenon Thruster (NEXT) system and a notional 25-kW engine. The Phase II project matured the laboratory model into a protoengineering model ion thruster. This involved the evolution of the discharge chamber to a high-performance thruster by performance testing and characterization via simulated and full beam extraction testing. Through such testing, the team optimized the design and built a protoengineering model thruster. Coupled with gridded ion thruster technology, this technology can enable a wide range of missions, including ambitious near-Earth NASA missions, Department of Defense missions, and commercial satellite activities.

Laser or charged-particle-beam fusion reactor with direct electric generation by magnetic flux compression

DOEpatents

Lasche, G.P.

1983-09-29

The invention is a laser or particle-beam-driven fusion reactor system which takes maximum advantage of both the very short pulsed nature of the energy release of inertial confinement fusion (ICF) and the very small volumes within which the thermonuclear burn takes place. The pulsed nature of ICF permits dynamic direct energy conversion schemes such as magnetohydrodynamic (MHD) generation and magnetic flux compression; the small volumes permit very compact blanket geometries. By fully exploiting these characteristics of ICF, it is possible to design a fusion reactor with exceptionally high power density, high net electric efficiency, and low neutron-induced radioactivity. The invention includes a compact blanket design and method and apparatus for obtaining energy utilizing the compact blanket.

Fusion-Enabled Pluto Orbiter and Lander

NASA Technical Reports Server (NTRS)

Thomas, Stephanie

2017-01-01

The Pluto orbiter mission proposed here is credible and exciting. The benefits to this and all outer-planet and interstellar-probe missions are difficult to overstate. The enabling technology, Direct Fusion Drive, is a unique fusion engine concept based on the Princeton Field-Reversed Configuration (PFRC) fusion reactor under development at the Princeton Plasma Physics Laboratory. The truly game-changing levels of thrust and power in a modestly sized package could integrate with our current launch infrastructure while radically expanding the science capability of these missions. During this Phase I effort, we made great strides in modeling the engine efficiency, thrust, and specific impulse and analyzing feasible trajectories. Based on 2D fluid modeling of the fusion reactors outer stratum, its scrape-off-layer (SOL), we estimate achieving 2.5 to 5 N of thrust for each megawatt of fusion power, reaching a specific impulse, Isp, of about 10,000 s. Supporting this model are particle-in-cell calculations of energy transfer from the fusion products to the SOL electrons. Subsequently, this energy is transferred to the ions as they expand through the magnetic nozzle and beyond. Our point solution for the Pluto mission now delivers 1000 kg of payload to Pluto orbit in 3.75 years using 7.5 N constant thrust. This could potentially be achieved with a single 1 MW engine. The departure spiral from Earth orbit and insertion spiral to Pluto orbit require only a small portion of the total delta-V. Departing from low Earth orbit reduces mission cost while increasing available mission mass. The payload includes a lander, which utilizes a standard green propellant engine for the landing sequence. The lander has about 4 square meters of solar panels mounted on a gimbal that allows it to track the orbiter, which beams 30 to 50 kW of power using a 1080 nm laser. Optical communication provides dramatically high data rates back to Earth. Our mass modeling investigations revealed that if

High-efficiency resonant coupled wireless power transfer via tunable impedance matching

NASA Astrophysics Data System (ADS)

Anowar, Tanbir Ibne; Barman, Surajit Das; Wasif Reza, Ahmed; Kumar, Narendra

2017-10-01

For magnetic resonant coupled wireless power transfer (WPT), the axial movement of near-field coupled coils adversely degrades the power transfer efficiency (PTE) of the system and often creates sub-resonance. This paper presents a tunable impedance matching technique based on optimum coupling tuning to enhance the efficiency of resonant coupled WPT system. The optimum power transfer model is analysed from equivalent circuit model via reflected load principle, and the adequate matching are achieved through the optimum tuning of coupling coefficients at both the transmitting and receiving end of the system. Both simulations and experiments are performed to evaluate the theoretical model of the proposed matching technique, and results in a PTE over 80% at close coil proximity without shifting the original resonant frequency. Compared to the fixed coupled WPT, the extracted efficiency shows 15.1% and 19.9% improvements at the centre-to-centre misalignment of 10 and 70 cm, respectively. Applying this technique, the extracted S21 parameter shows more than 10 dB improvements at both strong and weak couplings. Through the developed model, the optimum coupling tuning also significantly improves the performance over matching techniques using frequency tracking and tunable matching circuits.

Toward high-energy-density, high-efficiency, and moderate-temperature chip-scale thermophotovoltaics

PubMed Central

Chan, Walker R.; Bermel, Peter; Pilawa-Podgurski, Robert C. N.; Marton, Christopher H.; Jensen, Klavs F.; Senkevich, Jay J.; Joannopoulos, John D.; Soljačić, Marin; Celanovic, Ivan

2013-01-01

The challenging problem of ultra-high-energy-density, high-efficiency, and small-scale portable power generation is addressed here using a distinctive thermophotovoltaic energy conversion mechanism and chip-based system design, which we name the microthermophotovoltaic (μTPV) generator. The approach is predicted to be capable of up to 32% efficient heat-to-electricity conversion within a millimeter-scale form factor. Although considerable technological barriers need to be overcome to reach full performance, we have performed a robust experimental demonstration that validates the theoretical framework and the key system components. Even with a much-simplified μTPV system design with theoretical efficiency prediction of 2.7%, we experimentally demonstrate 2.5% efficiency. The μTPV experimental system that was built and tested comprises a silicon propane microcombustor, an integrated high-temperature photonic crystal selective thermal emitter, four 0.55-eV GaInAsSb thermophotovoltaic diodes, and an ultra-high-efficiency maximum power-point tracking power electronics converter. The system was demonstrated to operate up to 800 °C (silicon microcombustor temperature) with an input thermal power of 13.7 W, generating 344 mW of electric power over a 1-cm2 area. PMID:23440220

Extreme triple asymmetric (ETAS) epitaxial designs for increased efficiency at high powers in 9xx-nm diode lasers

NASA Astrophysics Data System (ADS)

Kaul, T.; Erbert, G.; Maaßdorf, A.; Martin, D.; Crump, P.

2018-02-01

Broad area lasers that are tailored to be most efficient at the highest achievable optical output power are sought by industry to decrease operation costs and improve system performance. Devices using Extreme-Double-ASymmetric (EDAS) epitaxial designs are promising candidates for improved efficiency at high optical output powers due to low series resistance, low optical loss and low carrier leakage. However, EDAS designs leverage ultra-thin p-side waveguides, meaning that the optical mode is shifted into the n-side waveguide, resulting in a low optical confinement in the active region, low gain and hence high threshold current, limiting peak performance. We introduce here explicit design considerations that enable EDAS-based devices to be developed with increased optical confinement in the active layer without changing the p-side layer thicknesses. Specifically, this is realized by introducing a third asymmetric component in the vicinity of the quantum well. We call this approach Extreme-Triple-ASymmetric (ETAS) design. A series of ETAS-based vertical designs were fabricated into broad area lasers that deliver up to 63% power conversion efficiency at 14 W CW optical output power from a 100 μm stripe laser, which corresponds to the operation point of a kW optical output power in a laser bar. The design process, the impact of structural changes on power saturation mechanisms and finally devices with improved performance will be presented.

High efficiency quantum cascade laser frequency comb.

PubMed

Lu, Quanyong; Wu, Donghai; Slivken, Steven; Razeghi, Manijeh

2017-03-06

An efficient mid-infrared frequency comb source is of great interest to high speed, high resolution spectroscopy and metrology. Here we demonstrate a mid-IR quantum cascade laser frequency comb with a high power output and narrow beatnote linewidth at room temperature. The active region was designed with a strong-coupling between the injector and the upper lasing level for high internal quantum efficiency and a broadband gain. The group velocity dispersion was engineered for efficient, broadband mode-locking via four wave mixing. The comb device exhibits a narrow intermode beatnote linewidth of 50.5 Hz and a maximum wall-plug efficiency of 6.5% covering a spectral coverage of 110 cm -1 at λ ~ 8 μm. The efficiency is improved by a factor of 6 compared with previous demonstrations. The high power efficiency and narrow beatnote linewidth will greatly expand the applications of quantum cascade laser frequency combs including high-precision remote sensing and spectroscopy.

High efficiency quantum cascade laser frequency comb

PubMed Central

Lu, Quanyong; Wu, Donghai; Slivken, Steven; Razeghi, Manijeh

2017-01-01

An efficient mid-infrared frequency comb source is of great interest to high speed, high resolution spectroscopy and metrology. Here we demonstrate a mid-IR quantum cascade laser frequency comb with a high power output and narrow beatnote linewidth at room temperature. The active region was designed with a strong-coupling between the injector and the upper lasing level for high internal quantum efficiency and a broadband gain. The group velocity dispersion was engineered for efficient, broadband mode-locking via four wave mixing. The comb device exhibits a narrow intermode beatnote linewidth of 50.5 Hz and a maximum wall-plug efficiency of 6.5% covering a spectral coverage of 110 cm−1 at λ ~ 8 μm. The efficiency is improved by a factor of 6 compared with previous demonstrations. The high power efficiency and narrow beatnote linewidth will greatly expand the applications of quantum cascade laser frequency combs including high-precision remote sensing and spectroscopy. PMID:28262834

Non-electric applications for magneto-inertial fusion

NASA Astrophysics Data System (ADS)

Slough, John

2016-10-01

In addition to the generation of commercial electric power, there are several other applications for an intense pulse of neutrons that would be produced by magneto-inertial fusion (MIF) systems. Many of these applications can be achieved without the need for a fully developed reactor at high gain, and could thus be pursued at a much earlier stage of development which would dramatically reduce the risk of the long-term development and concern for the expense of an all-encompassing, single use system such as the tokamak or stellerator. A short list of applications well suited for MIF would include: (1) production of radioisotopes for medical applications and research, (2) efficient, high power propulsion through direct fusion heating of lithium propellants (3) Noninvasive interrogation of objects for homeland security (4) neutron radiography and tomography (5) destruction of long-lived radioactive waste, and (6) breeding of proliferation proof fissile fuel for existing nuclear reactors. These applications could all be pursued at lower neutron yield, but clearly the energy goals are by far the most significant and far reaching such as applying fusion energy as a hybrid to enable thorium cycle reactors which produce very little waste compared to the current uranium reactors. A discussion of how MIF could be configured and utilized to realize several of these uses will be discussed.

Present status of liquid metal research for a fusion reactor

NASA Astrophysics Data System (ADS)

Tabarés, Francisco L.

2016-01-01

Although the use of solid materials as targets of divertor plasmas in magnetic fusion research is accepted as the standard solution for the very challenging issue of power and particle handling in a fusion reactor, a generalized feeling that the present options chosen for ITER will not represent the best choice for a reactor is growing up. The problems found for tungsten, the present selection for the divertor target of ITER, in laboratory tests and in hot plasma fusion devices suggest so. Even in the absence of the strong neutron irradiation expected in a reactor, issues like surface melting, droplet ejection, surface cracking, dust generation, etc., call for alternative solutions in a long pulse, high efficient fusion energy-producing continuous machine. Fortunately enough, decades of research on plasma facing materials based on liquid metals (LMs) have produced a wealth of appealing ideas that could find practical application in the route to the realization of a commercial fusion power plant. The options presently available, although in a different degree of maturity, range from full coverage of the inner wall of the device with liquid metals, so that power and particle exhaust together with neutron shielding could be provided, to more conservative combinations of liquid metal films and conventional solid targets basically representing a sort of high performance, evaporative coating for the alleviation of the surface degradation issues found so far. In this work, an updated review of worldwide activities on LM research is presented, together with some open issues still remaining and some proposals based on simple physical considerations leading to the optimization of the most conservative alternatives.

Block Ignition Inertial Confinement Fusion (ICF) with Condensed Matter Cluster Type Targets for p-B11 Powered Space Propulsion

DOE Office of Scientific and Technical Information (OSTI.GOV)

Miley, George H.; Hora, H.; Badziak, J.

The use of laser-driven Inertial Confinement Fusion (ICF) for space propulsion has been the subject of several earlier conceptual design studies, (see: Orth, 1998; and other references therein). However, these studies were based on older ICF technology using either 'direct' or 'in-direct x-ray driven' type target irradiation. Important new directions have opened for laser ICF in recent years following the development of 'chirped' lasers capable of ultra short pulses with powers of TW up to few PW which leads to the concept of 'fast ignition (FI)' to achieve higher energy gains from target implosions. In a recent publication the authorsmore » showed that use of a modified type of FI, termed 'block ignition' (Miley et al., 2008), could meet many of the requirements anticipated (but not then available) by the designs of the Vehicle for Interplanetary Space Transport Applications (VISTA) ICF fusion propulsion ship (Orth, 2008) for deep space missions. Subsequently the first author devised and presented concepts for imbedding high density condensed matter 'clusters' of deuterium into the target to obtain ultra high local fusion reaction rates (Miley, 2008). Such rates are possible due to the high density of the clusters (over an order of magnitude above cryogenic deuterium). Once compressed by the implosion, the yet higher density gives an ultra high reaction rate over the cluster volume since the fusion rate is proportional to the square of the fuel density. Most recently, a new discovery discussed here indicates that the target matrix could be composed of B{sup 11} with proton clusters imbedded. This then makes p-B{sup 11} fusion practical, assuming all of the physics issues such as stability of the clusters during compression are resolved. Indeed, p-B{sup 11} power is ideal for fusion propulsion since it has a minimum of unwanted side products while giving most of the reaction energy to energetic alpha particles which can be directed into an exhaust (propulsion

Cyanopyridine Based Bipolar Host Materials for Green Electrophosphorescence with Extremely Low Turn-On Voltages and High Power Efficiencies.

PubMed

Li, Wei; Li, Jiuyan; Liu, Di; Li, Deli; Wang, Fang

2016-08-24

Low driving voltage and high power efficiency are basic requirements when practical applications of organic light emitting diodes (OLEDs) in displays and lighting are considered. Two novel host materials m-PyCNmCP and 3-PyCNmCP incorporating cyanopyridine moiety as electron-transporting unit are developed for use in fac-tris(2-phenylpyridine)iridium(III) (Ir(ppy)3) based green phosphorescent OLEDs (PhOLEDs). Extremely low turn-on voltages of 2.01 and 2.27 V are realized, which are even lower than the theoretical limit of the emitted photon energy (hv)/electron charge (e) (2.37 V) of Ir(ppy)3. High power efficiency of 101.4 lm/W (corresponding to a maximum external quantum efficiency of 18.4%) and 119.3 lm/W (24.7%) are achieved for m-PyCNmCP and 3-PyCNmCP based green PhOLEDs. The excellent EL performance benefits from the ideal parameters of host materials by combining cyano and pyridine to enhance the n-type feature. The energetic favorable alignment of HOMO/LUMO levels of hosts with adjacent layers and the dopant for easy charge injections and direct charge trapping by dopant, their bipolar feature to balance charge transportations, sufficiently high triplet energy and small singlet/triplet energy difference (0.38 and 0.43 eV) combine to be responsible for the extremely low driving voltages and high power efficiencies of the green PhOLEDs.

confFuse: High-Confidence Fusion Gene Detection across Tumor Entities.

PubMed

Huang, Zhiqin; Jones, David T W; Wu, Yonghe; Lichter, Peter; Zapatka, Marc

2017-01-01

Background: Fusion genes play an important role in the tumorigenesis of many cancers. Next-generation sequencing (NGS) technologies have been successfully applied in fusion gene detection for the last several years, and a number of NGS-based tools have been developed for identifying fusion genes during this period. Most fusion gene detection tools based on RNA-seq data report a large number of candidates (mostly false positives), making it hard to prioritize candidates for experimental validation and further analysis. Selection of reliable fusion genes for downstream analysis becomes very important in cancer research. We therefore developed confFuse, a scoring algorithm to reliably select high-confidence fusion genes which are likely to be biologically relevant. Results: confFuse takes multiple parameters into account in order to assign each fusion candidate a confidence score, of which score ≥8 indicates high-confidence fusion gene predictions. These parameters were manually curated based on our experience and on certain structural motifs of fusion genes. Compared with alternative tools, based on 96 published RNA-seq samples from different tumor entities, our method can significantly reduce the number of fusion candidates (301 high-confidence from 8,083 total predicted fusion genes) and keep high detection accuracy (recovery rate 85.7%). Validation of 18 novel, high-confidence fusions detected in three breast tumor samples resulted in a 100% validation rate. Conclusions: confFuse is a novel downstream filtering method that allows selection of highly reliable fusion gene candidates for further downstream analysis and experimental validations. confFuse is available at https://github.com/Zhiqin-HUANG/confFuse.

OSIRIS and SOMBRERO Inertial Fusion Power Plant Designs, Volume 2: Designs, Assessments, and Comparisons

DOE Office of Scientific and Technical Information (OSTI.GOV)

Meier, W. R.; Bieri, R. L.; Monsler, M. J.

1992-03-01

This is a comprehensive design study of two Inertial Fusion Energy (IFE) electric power plants. Conceptual designs are presented for a fusion reactor (called Osiris) using an induction-linac heavy-ion beam driver, and another (called SOMBRERO) using a KrF laser driver. The designs covered all aspects of IFE power plants, including the chambers, heat transport and power conversion systems, balance-of-plant facilities, target fabrication, target injection and tracking, as well as the heavy-ion and KrF drivers. The point designs were assessed and compared in terms of their environmental & safety aspects, reliability and availability, economics, and technology development needs.

Changing computing paradigms towards power efficiency

PubMed Central

Klavík, Pavel; Malossi, A. Cristiano I.; Bekas, Costas; Curioni, Alessandro

2014-01-01

Power awareness is fast becoming immensely important in computing, ranging from the traditional high-performance computing applications to the new generation of data centric workloads. In this work, we describe our efforts towards a power-efficient computing paradigm that combines low- and high-precision arithmetic. We showcase our ideas for the widely used kernel of solving systems of linear equations that finds numerous applications in scientific and engineering disciplines as well as in large-scale data analytics, statistics and machine learning. Towards this goal, we developed tools for the seamless power profiling of applications at a fine-grain level. In addition, we verify here previous work on post-FLOPS/W metrics and show that these can shed much more light in the power/energy profile of important applications. PMID:24842033

The strategy of fusion genes construction determines efficient expression of introduced transcription factors.

PubMed

Adamus, Tomasz; Konieczny, Paweł; Sekuła, Małgorzata; Sułkowski, Maciej; Majka, Marcin

2014-01-01

The main goal in gene therapy and biomedical research is an efficient transcription factors (TFs) delivery system. SNAIL, a zinc finger transcription factor, is strongly involved in tumor, what makes its signaling pathways an interesting research subject. The necessity of tracking activation of intracellular pathways has prompted fluorescent proteins usage as localization markers. Advanced molecular cloning techniques allow to generate fusion proteins from fluorescent markers and transcription factors. Depending on fusion strategy, the protein expression levels and nuclear transport ability are significantly different. The P2A self-cleavage motif through its cleavage ability allows two single proteins to be simultaneously expressed. The aim of this study was to compare two strategies for introducing a pair of genes using expression vector system. We have examined GFP and SNAI1 gene fusions by comprising common nucleotide polylinker (multiple cloning site) or P2A motif in between them, resulting in one fusion or two independent protein expressions respectively. In each case transgene expression levels and translation efficiency as well as nuclear localization of expressed protein have been analyzed. Our data showed that usage of P2A motif provides more effective nuclear transport of SNAIL transcription factor than conventional genes linker. At the same time the fluorescent marker spreads evenly in subcellular space.

High Efficiency mm-Wave Transmitter Array

DTIC Science & Technology

2016-09-01

SECURITY CLASSIFICATION OF: High efficiency, high power transmitters integrated in silicon at 45, 94 and 138 GHz were developed. Our approach...employs CMOS-SOI and SiGe HBT unit amplifiers, power -combined in free-space using antenna arrays to attain high power levels. In the baseline approach...the-art were made. At 45GHz, a single CMOS chip produced an RF power of 630mW, which yielded an EIRP of 1. REPORT DATE (DD-MM-YYYY) 4. TITLE AND

High-performance and power-efficient 2×2 optical switch on Silicon-on-Insulator.

PubMed

Han, Zheng; Moille, Grégory; Checoury, Xavier; Bourderionnet, Jérôme; Boucaud, Philippe; De Rossi, Alfredo; Combrié, Sylvain

2015-09-21

A compact (15µm × 15µm) and highly-optimized 2×2 optical switch is demonstrated on a CMOS-compatible photonic crystal technology. On-chip insertion loss are below 1 dB, static and dynamic contrast are 40 dB and >20 dB respectively. Owing to efficient thermo-optic design, the power consumption is below 3 mW while the switching time is 1 µs.

16 W output power by high-efficient spectral beam combining of DBR-tapered diode lasers.

PubMed

Müller, André; Vijayakumar, Deepak; Jensen, Ole Bjarlin; Hasler, Karl-Heinz; Sumpf, Bernd; Erbert, Götz; Andersen, Peter E; Petersen, Paul Michael

2011-01-17

Up to 16 W output power has been obtained using spectral beam combining of two 1063 nm DBR-tapered diode lasers. Using a reflecting volume Bragg grating, a combining efficiency as high as 93.7% is achieved, resulting in a single beam with high spatial coherence. The result represents the highest output power achieved by spectral beam combining of two single element tapered diode lasers. Since spectral beam combining does not affect beam propagation parameters, M2-values of 1.8 (fast axis) and 3.3 (slow axis) match the M2-values of the laser with lowest spatial coherence. The principle of spectral beam combining used in our experiments can be expanded to combine more than two tapered diode lasers and hence it is expected that the output power may be increased even further in the future.

(Power sector efficiency analysis in Costa Rica). [Power Sector Efficiency Analysis in Costa Rica

DOE Office of Scientific and Technical Information (OSTI.GOV)

Waddle, D.B.

I traveled to San Jose, Costa Rica, to review the state of the electric power utility with a team of specialists, including a transmission and distribution specialist, a hydroelectric engineering specialist, and a thermal power plant specialist. The purpose of the mission was to determine the costs and benefits of efficiency improvements to supply side technologies employed by the Instituto Costarricense de Electricidad, the national power company in Costa Rica, and the potential contribution of these efficiency measures to the future electric power needs of Costa Rica.

Exercise efficiency of low power output cycling.

PubMed

Reger, M; Peterman, J E; Kram, R; Byrnes, W C

2013-12-01

Exercise efficiency at low power outputs, energetically comparable to daily living activities, can be influenced by homeostatic perturbations (e.g., weight gain/loss). However, an appropriate efficiency calculation for low power outputs used in these studies has not been determined. Fifteen active subjects (seven females, eight males) performed 14, 5-min cycling trials: two types of seated rest (cranks vertical and horizontal), passive (motor-driven) cycling, no-chain cycling, no-load cycling, cycling at low (10, 20, 30, 40 W), and moderate (50, 60, 80, 100, 120 W) power outputs. Mean delta efficiency was 57% for low power outputs compared to 41.3% for moderate power outputs. Means for gross (3.6%) and net (5.7%) efficiencies were low at the lowest power output. At low power outputs, delta and work efficiency values exceeded theoretical values. In conclusion, at low power outputs, none of the common exercise efficiency calculations gave values comparable to theoretical muscle efficiency. However, gross efficiency and the slope and intercept of the metabolic power vs mechanical power output regression provide insights that are still valuable when studying homeostatic perturbations. © 2012 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Conceptual design of a laser fusion power plant. Part I. An integrated facility

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

This study is a new preliminary conceptual design and economic analysis of an inertial confinement fusion (ICF) power plant performed by Bechtel under the direction of Lawrence Livermore National Laboratory (LLNL). The purpose of a new conceptual design is to examine alternatives to the LLNL HYLIFE power plant and to incorporate information from the recent liquid metal cooled power plant conceptual design study (CDS) into the reactor system and balance of plant design. A key issue in the design of a laser fusion power plant is the degree of symmetry in the illumination of the target that will be requiredmore » for a proper burn. Because this matter is expected to remain unresolved for some time, another purpose of this study is to determine the effect of symmetry requirements on the total plant size, layout, and cost.« less

More Efficient Power Conversion for EVs: Gallium-Nitride Advanced Power Semiconductor and Packaging

DOE Office of Scientific and Technical Information (OSTI.GOV)

None

2010-02-01

Broad Funding Opportunity Announcement Project: Delphi is developing power converters that are smaller and more energy efficient, reliable, and cost-effective than current power converters. Power converters rely on power transistors which act like a very precisely controlled on-off switch, controlling the electrical energy flowing through an electrical circuit. Most power transistors today use silicon (Si) semiconductors. However, Delphi is using semiconductors made with a thin layer of gallium-nitride (GaN) applied on top of the more conventional Si material. The GaN layer increases the energy efficiency of the power transistor and also enables the transistor to operate at much higher temperatures,more » voltages, and power-density levels compared to its Si counterpart. Delphi is packaging these high-performance GaN semiconductors with advanced electrical connections and a cooling system that extracts waste heat from both sides of the device to further increase the device’s efficiency and allow more electrical current to flow through it. When combined with other electronic components on a circuit board, Delphi’s GaN power transistor package will help improve the overall performance and cost-effectiveness of HEVs and EVs.« less

A local approach for focussed Bayesian fusion

NASA Astrophysics Data System (ADS)

Sander, Jennifer; Heizmann, Michael; Goussev, Igor; Beyerer, Jürgen

2009-04-01

Local Bayesian fusion approaches aim to reduce high storage and computational costs of Bayesian fusion which is separated from fixed modeling assumptions. Using the small world formalism, we argue why this proceeding is conform with Bayesian theory. Then, we concentrate on the realization of local Bayesian fusion by focussing the fusion process solely on local regions that are task relevant with a high probability. The resulting local models correspond then to restricted versions of the original one. In a previous publication, we used bounds for the probability of misleading evidence to show the validity of the pre-evaluation of task specific knowledge and prior information which we perform to build local models. In this paper, we prove the validity of this proceeding using information theoretic arguments. For additional efficiency, local Bayesian fusion can be realized in a distributed manner. Here, several local Bayesian fusion tasks are evaluated and unified after the actual fusion process. For the practical realization of distributed local Bayesian fusion, software agents are predestinated. There is a natural analogy between the resulting agent based architecture and criminal investigations in real life. We show how this analogy can be used to improve the efficiency of distributed local Bayesian fusion additionally. Using a landscape model, we present an experimental study of distributed local Bayesian fusion in the field of reconnaissance, which highlights its high potential.

Changing computing paradigms towards power efficiency.

PubMed

Klavík, Pavel; Malossi, A Cristiano I; Bekas, Costas; Curioni, Alessandro

2014-06-28

Power awareness is fast becoming immensely important in computing, ranging from the traditional high-performance computing applications to the new generation of data centric workloads. In this work, we describe our efforts towards a power-efficient computing paradigm that combines low- and high-precision arithmetic. We showcase our ideas for the widely used kernel of solving systems of linear equations that finds numerous applications in scientific and engineering disciplines as well as in large-scale data analytics, statistics and machine learning. Towards this goal, we developed tools for the seamless power profiling of applications at a fine-grain level. In addition, we verify here previous work on post-FLOPS/W metrics and show that these can shed much more light in the power/energy profile of important applications. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

High-Frequency ac Power-Distribution System

NASA Technical Reports Server (NTRS)

Hansen, Irving G.; Mildice, James

1987-01-01

Loads managed automatically under cycle-by-cycle control. 440-V rms, 20-kHz ac power system developed. System flexible, versatile, and "transparent" to user equipment, while maintaining high efficiency and low weight. Electrical source, from dc to 2,200-Hz ac converted to 440-V rms, 20-kHz, single-phase ac. Power distributed through low-inductance cables. Output power either dc or variable ac. Energy transferred per cycle reduced by factor of 50. Number of parts reduced by factor of about 5 and power loss reduced by two-thirds. Factors result in increased reliability and reduced costs. Used in any power-distribution system requiring high efficiency, high reliability, low weight, and flexibility to handle variety of sources and loads.

Requirements for high-efficiency solar cells

NASA Technical Reports Server (NTRS)

Sah, C. T.

1986-01-01

Minimum recombination and low injection level are essential for high efficiency. Twenty percent AM1 efficiency requires a dark recombination current density of 2 x 10 to the minus 13th power A/sq cm and a recombination center density of less than 10 to the 10th power /cu cm. Recombination mechanisms at thirteen locations in a conventional single crystalline silicon cell design are reviewed. Three additional recombination locations are described at grain boundaries in polycrystalline cells. Material perfection and fabrication process optimization requirements for high efficiency are outlined. Innovative device designs to reduce recombination in the bulk and interfaces of single crystalline cells and in the grain boundary of polycrystalline cells are reviewed.

Fusion energy from the Moon for the twenty-first century

NASA Technical Reports Server (NTRS)

Kulcinski, G. L.; Cameron, E. N.; Santarius, J. F.; Sviatoslavsky, I. N.; Wittenberg, L. J.; Schmitt, Harrison H.

1992-01-01

It is shown in this paper that the D-He-3 fusion fuel cycle is not only credible from a physics standpoint, but that its breakeven and ignition characteristics could be developed on roughly the same time schedule as the DT cycle. It was also shown that the extremely low fraction of power in neutrons, the lack of significant radioactivity in the reactants, and the potential for very high conversion efficiencies, can result in definite advantages for the D-He-3 cycle with respect to DT fusion and fission reactors in the twenty-first century. More specifically, the D-He-3 cycle can accomplish the following: (1) eliminate the need for deep geologic waste burial facilities and the wastes can qualify for Class A, near-surface land burial; (2) allow 'inherently safe' reactors to be built that, under the worst conceivable accident, cannot cause a civilian fatality or result in a significant (greater than 100 mrem) exposure to a member of the public; (3) reduce the radiation damage levels to a point where no scheduled replacement of reactor structural components is required, i.e., full reactor lifetimes (approximately 30 FPY) can be credibly claimed; (4) increase the reliability and availability of fusion reactors compared to DT systems because of the greatly reduced radioactivity, the low neutron damage, and the elimination of T breeding; and (5) greatly reduce the capital costs of fusion power plants (compared to DT systems) by as much as 50 percent and present the potential for a significant reduction on the COE. The concepts presented in this paper tie together two of the most ambitious high-technology endeavors of the twentieth century: the development of controlled thermonuclear fusion for civilian power applications and the utilization of outer space for the benefit of mankind on Earth.

Fusion energy from the Moon for the twenty-first century

NASA Astrophysics Data System (ADS)

Kulcinski, G. L.; Cameron, E. N.; Santarius, J. F.; Sviatoslavsky, I. N.; Wittenberg, L. J.; Schmitt, Harrison H.

1992-09-01

It is shown in this paper that the D-He-3 fusion fuel cycle is not only credible from a physics standpoint, but that its breakeven and ignition characteristics could be developed on roughly the same time schedule as the DT cycle. It was also shown that the extremely low fraction of power in neutrons, the lack of significant radioactivity in the reactants, and the potential for very high conversion efficiencies, can result in definite advantages for the D-He-3 cycle with respect to DT fusion and fission reactors in the twenty-first century. More specifically, the D-He-3 cycle can accomplish the following: (1) eliminate the need for deep geologic waste burial facilities and the wastes can qualify for Class A, near-surface land burial; (2) allow 'inherently safe' reactors to be built that, under the worst conceivable accident, cannot cause a civilian fatality or result in a significant (greater than 100 mrem) exposure to a member of the public; (3) reduce the radiation damage levels to a point where no scheduled replacement of reactor structural components is required, i.e., full reactor lifetimes (approximately 30 FPY) can be credibly claimed; (4) increase the reliability and availability of fusion reactors compared to DT systems because of the greatly reduced radioactivity, the low neutron damage, and the elimination of T breeding; and (5) greatly reduce the capital costs of fusion power plants (compared to DT systems) by as much as 50 percent and present the potential for a significant reduction on the COE. The concepts presented in this paper tie together two of the most ambitious high-technology endeavors of the twentieth century: the development of controlled thermonuclear fusion for civilian power applications and the utilization of outer space for the benefit of mankind on Earth.

Task toward a Realization of Commercial Tokamak Fusion Plants in 2050 -The Role of ITER and the Succeeding Developments- 4.Technology and Material Research in Fusion Power Plant Development

NASA Astrophysics Data System (ADS)

Akiba, Masato; Matsui, Hideki; Takatsu, Hideyuki; Konishi, Satoshi

Technical issues regarding the fusion power plant that are required to be developed in the period of ITER construction and operation, both with ITER and with other facilities that complement ITER are described in this section. Three major fields are considered to be important in fusion technology. Section 4.1 summarizes blanket study, and ITER Test Blanket Module (TBM) development that focuses its effort on the first generation power blanket to be installed in DEMO. ITER will be equipped with 6 TBMs which are developed under each party's fusion program. In Japan, the solid breeder using water as a coolant is the primary candidate, and He-cooled pebble bed is the alternative. Other liquid options such as LiPb, Li or molten salt are developed by other parties' initiatives. The Test Blanket Working Group (TBWG) is coordinating these efforts. Japanese universities are investigating advanced concepts and fundamental crosscutting technologies. Section 4.2 introduces material development and particularly, the international irradiation facility, IFMIF. Reduced activation ferritic/martensitic steels are identified as promising candidates for the structural material of the first generation fusion blanket, while and vanadium alloy and SiC/SiC composite are pursued as advanced options. The IFMIF is currently planning the next phase of joint activity, EVEDA (Engineering Validation and Engineering Design Activity) that encompasses construction. Material studies together with the ITER TBM will provide essential technical information for development of the fusion power plant. Other technical issues to be addressed regarding the first generation fusion power plant are summarized in section 4.3. Development of components for ITER made remarkable progress for the major essential technology also necessary for future fusion plants, however many still need further improvements toward power plant. Such areas includes; the divertor, plasma heating/current drive, magnets, tritium, and

An efficient method for the fusion of light field refocused images

NASA Astrophysics Data System (ADS)

Wang, Yingqian; Yang, Jungang; Xiao, Chao; An, Wei

2018-04-01

Light field cameras have drawn much attention due to the advantage of post-capture adjustments such as refocusing after exposure. The depth of field in refocused images is always shallow because of the large equivalent aperture. As a result, a large number of multi-focus images are obtained and an all-in-focus image is demanded. Consider that most multi-focus image fusion algorithms do not particularly aim at large numbers of source images and traditional DWT-based fusion approach has serious problems in dealing with lots of multi-focus images, causing color distortion and ringing effect. To solve this problem, this paper proposes an efficient multi-focus image fusion method based on stationary wavelet transform (SWT), which can deal with a large quantity of multi-focus images with shallow depth of fields. We compare SWT-based approach with DWT-based approach on various occasions. And the results demonstrate that the proposed method performs much better both visually and quantitatively.

Self-Powered Wireless Smart Sensor Node Enabled by an Ultrastable, Highly Efficient, and Superhydrophobic-Surface-Based Triboelectric Nanogenerator.

PubMed

Zhao, Kun; Wang, Zhong Lin; Yang, Ya

2016-09-27

Wireless sensor networks will be responsible for a majority of the fast growth in intelligent systems in the next decade. However, most of the wireless smart sensor nodes require an external power source such as a Li-ion battery, where the labor cost and environmental waste issues of replacing batteries have largely limited the practical applications. Instead of using a Li-ion battery, we report an ultrastable, highly efficient, and superhydrophobic-surface-based triboelectric nanogenerator (TENG) to scavenge wind energy for sustainably powering a wireless smart temperature sensor node. There is no decrease in the output voltage and current of the TENG after continuous working for about 14 h at a wind speed of 12 m/s. Through a power management circuit, the TENG can deliver a constant output voltage of 3.3 V and a pulsed output current of about 100 mA to achieve highly efficient energy storage in a capacitor. A wireless smart temperature sensor node can be sustainably powered by the TENG for sending the real-time temperature data to an iPhone under a working distance of 26 m, demonstrating the feasibility of the self-powered wireless smart sensor networks.

High efficiency, long life terrestrial solar panel

NASA Technical Reports Server (NTRS)

Chao, T.; Khemthong, S.; Ling, R.; Olah, S.

1977-01-01

The design of a high efficiency, long life terrestrial module was completed. It utilized 256 rectangular, high efficiency solar cells to achieve high packing density and electrical output. Tooling for the fabrication of solar cells was in house and evaluation of the cell performance was begun. Based on the power output analysis, the goal of a 13% efficiency module was achievable.

Log-Gabor Energy Based Multimodal Medical Image Fusion in NSCT Domain

PubMed Central

Yang, Yong; Tong, Song; Huang, Shuying; Lin, Pan

2014-01-01

Multimodal medical image fusion is a powerful tool in clinical applications such as noninvasive diagnosis, image-guided radiotherapy, and treatment planning. In this paper, a novel nonsubsampled Contourlet transform (NSCT) based method for multimodal medical image fusion is presented, which is approximately shift invariant and can effectively suppress the pseudo-Gibbs phenomena. The source medical images are initially transformed by NSCT followed by fusing low- and high-frequency components. The phase congruency that can provide a contrast and brightness-invariant representation is applied to fuse low-frequency coefficients, whereas the Log-Gabor energy that can efficiently determine the frequency coefficients from the clear and detail parts is employed to fuse the high-frequency coefficients. The proposed fusion method has been compared with the discrete wavelet transform (DWT), the fast discrete curvelet transform (FDCT), and the dual tree complex wavelet transform (DTCWT) based image fusion methods and other NSCT-based methods. Visually and quantitatively experimental results indicate that the proposed fusion method can obtain more effective and accurate fusion results of multimodal medical images than other algorithms. Further, the applicability of the proposed method has been testified by carrying out a clinical example on a woman affected with recurrent tumor images. PMID:25214889

Insulin chains as efficient fusion tags for prokaryotic expression of short peptides.

PubMed

Deng, Ligang; Xue, Xiaoying; Shen, Cangjie; Song, Xiaohan; Wang, Chunyang; Wang, Nan

2017-10-01

Insulin chains are usually expressed in Escherichia coli as fusion proteins with different tags, including various low molecular weight peptide tags. The objective of this study was to determine if insulin chains could facilitate the recombinant expression of other target proteins, with an emphasis on low molecular weight peptides. A series of short peptides were fused to mini-proinsulin, chain B or chain A, and induced for expression in Escherichia coli. All the tested peptides including glucagon-like peptide 1 (GLP-1), a C-terminal extended GLP-1, oxyntomodulin, enfuvirtide, linaclotide, and an unstructured artificial peptide were expressed with reasonable yields, identified by Tricine-SDS-PAGE and immunoblotting. All recombinant products were expressed in inclusion bodies. The effective accumulation of products was largely attributed to the insoluble expression induced by fusion with insulin chains, and was confirmed by the fusion expression of transthyretin. Insulin chains thus show promise as efficient fusion tags for mass production of heterologous peptides in prokaryotes. Copyright © 2017 Elsevier Inc. All rights reserved.

Process Model of A Fusion Fuel Recovery System for a Direct Drive IFE Power Reactor

NASA Astrophysics Data System (ADS)

Natta, Saswathi; Aristova, Maria; Gentile, Charles

2008-11-01

A task has been initiated to develop a detailed representative model for the fuel recovery system (FRS) in the prospective direct drive inertial fusion energy (IFE) reactor. As part of the conceptual design phase of the project, a chemical process model is developed in order to observe the interaction of system components. This process model is developed using FEMLAB Multiphysics software with the corresponding chemical engineering module (CEM). Initially, the reactants, system structure, and processes are defined using known chemical species of the target chamber exhaust. Each step within the Fuel recovery system is modeled compartmentally and then merged to form the closed loop fuel recovery system. The output, which includes physical properties and chemical content of the products, is analyzed after each step of the system to determine the most efficient and productive system parameters. This will serve to attenuate possible bottlenecks in the system. This modeling evaluation is instrumental in optimizing and closing the fusion fuel cycle in a direct drive IFE power reactor. The results of the modeling are presented in this paper.

High power diode laser Master Oscillator-Power Amplifier (MOPA)

NASA Technical Reports Server (NTRS)

Andrews, John R.; Mouroulis, P.; Wicks, G.

1994-01-01

High power multiple quantum well AlGaAs diode laser master oscillator - power amplifier (MOPA) systems were examined both experimentally and theoretically. For two pass operation, it was found that powers in excess of 0.3 W per 100 micrometers of facet length were achievable while maintaining diffraction-limited beam quality. Internal electrical-to-optical conversion efficiencies as high as 25 percent were observed at an internal amplifier gain of 9 dB. Theoretical modeling of multiple quantum well amplifiers was done using appropriate rate equations and a heuristic model of the carrier density dependent gain. The model gave a qualitative agreement with the experimental results. In addition, the model allowed exploration of a wider design space for the amplifiers. The model predicted that internal electrical-to-optical conversion efficiencies in excess of 50 percent should be achievable with careful system design. The model predicted that no global optimum design exists, but gain, efficiency, and optical confinement (coupling efficiency) can be mutually adjusted to meet a specific system requirement. A three quantum well, low optical confinement amplifier was fabricated using molecular beam epitaxial growth. Coherent beam combining of two high power amplifiers injected from a common master oscillator was also examined. Coherent beam combining with an efficiency of 93 percent resulted in a single beam having diffraction-limited characteristics. This beam combining efficiency is a world record result for such a system. Interferometric observations of the output of the amplifier indicated that spatial mode matching was a significant factor in the less than perfect beam combining. Finally, the system issues of arrays of amplifiers in a coherent beam combining system were investigated. Based upon experimentally observed parameters coherent beam combining could result in a megawatt-scale coherent beam with a 10 percent electrical-to-optical conversion efficiency.

High efficiency III-nitride light-emitting diodes

DOEpatents

Crawford, Mary; Koleske, Daniel; Cho, Jaehee; Zhu, Di; Noemaun, Ahmed; Schubert, Martin F; Schubert, E. Fred

2013-05-28

Tailored doping of barrier layers enables balancing of the radiative recombination among the multiple-quantum-wells in III-Nitride light-emitting diodes. This tailored doping enables more symmetric carrier transport and uniform carrier distribution which help to reduce electron leakage and thus reduce the efficiency droop in high-power III-Nitride LEDs. Mitigation of the efficiency droop in III-Nitride LEDs may enable the pervasive market penetration of solid-state-lighting technologies in high-power lighting and illumination.

Highly Efficient Amplifier for Ka-Band Communications

NASA Technical Reports Server (NTRS)

1996-01-01

An amplifier developed under a Small Business Innovation Research (SBIR) contract will have applications for both satellite and terrestrial communications. This power amplifier uses an innovative series bias arrangement of active devices to achieve over 40-percent efficiency at Ka-band frequencies with an output power of 0.66 W. The amplifier is fabricated on a 2.0- by 3.8-square millimeter chip through the use of Monolithic Microwave Integrated Circuit (MMIC) technology, and it uses state-of-the-art, Pseudomorphic High-Electron-Mobility Transistor (PHEMT) devices. Although the performance of the MMIC chip depends on these high-performance devices, the real innovations here are a unique series bias scheme, which results in a high-voltage chip supply, and careful design of the on-chip planar output stage combiner. This design concept has ramifications beyond the chip itself because it opens up the possibility of operation directly from a satellite power bus (usually 28 V) without a dc-dc converter. This will dramatically increase the overall system efficiency. Conventional microwave power amplifier designs utilize many devices all connected in parallel from the bias supply. This results in a low-bias voltage, typically 5 V, and a high bias current. With this configuration, substantial I(sup 2) R losses (current squared times resistance) may arise in the system bias-distribution network. By placing the devices in a series bias configuration, the total current is reduced, leading to reduced distribution losses. Careful design of the on-chip planar output stage power combiner is also important in minimizing losses. Using these concepts, a two-stage amplifier was designed for operation at 33 GHz and fabricated in a standard MMIC foundry process with 0.20-m PHEMT devices. Using a 20-V bias supply, the amplifier achieved efficiencies of over 40 percent with an output power of 0.66 W and a 16-dB gain over a 2-GHz bandwidth centered at 33 GHz. With a 28-V bias, a power

Short-term scheduling of crude oil operations in refinery with high-fusion-point oil and two transportation pipelines

NASA Astrophysics Data System (ADS)

Wu, NaiQi; Zhu, MengChu; Bai, LiPing; Li, ZhiWu

2016-07-01

In some refineries, storage tanks are located at two different sites, one for low-fusion-point crude oil and the other for high one. Two pipelines are used to transport different oil types. Due to the constraints resulting from the high-fusion-point oil transportation, it is challenging to schedule such a system. This work studies the scheduling problem from a control-theoretic perspective. It proposes to use a hybrid Petri net method to model the system. It then finds the schedulability conditions by analysing the dynamic behaviour of the net model. Next, it proposes an efficient scheduling method to minimize the cost of high-fusion-point oil transportation. Finally, it gives a complex industrial case study to show its application.

Modelling structural and plasma facing materials for fusion power plants: Recent advances and outstanding issues in the EURATOM fusion materials programme

NASA Astrophysics Data System (ADS)

Boutard, Jean-Louis; Dudarev, Sergei; Rieth, Michael

2011-10-01

EFDA Fusion Materials Topical Group was established at the end of 2007 to coordinate the EU effort on the development of structural and protection materials able to withstand the very demanding operating conditions of a future DEMO power plant. Focusing on a selection of well identified materials issues, including the behaviour of Reduced Activation Ferritic-Martensitic steels, and W-alloys under the foreseen operation conditions in a future DEMO, this paper describes recent advances in physical modelling and experimental validation, contributing to the definition of chemical composition and microstructure of materials with improved in-service stability at high temperature, high neutron flux and intense ion bombardment.

High-Efficiency, Low-Weight Power Transformer

NASA Technical Reports Server (NTRS)

Welsh, J. P.

1986-01-01

Technology for design and fabrication of radically new type of conductioncooled high-power (25 kVA) lightweight transformer having outstanding thermal and electrical characteristics. Fulfills longstanding need for conduction-cooled transformers and magnetics with low internal thermal resistances. Development techniques limited to conductive heat transfer, since other techniques such as liquid cooling, forced liquid cooling, and evaporative cooling of transformers impractical in zero-gravity space environment. Transformer uniquely designed: mechanical structure also serves as thermal paths for conduction cooling of magnetic core and windings.

Fusion Studies in Japan

NASA Astrophysics Data System (ADS)

Ogawa, Yuichi

2016-05-01

A new strategic energy plan decided by the Japanese Cabinet in 2014 strongly supports the steady promotion of nuclear fusion development activities, including the ITER project and the Broader Approach activities from the long-term viewpoint. Atomic Energy Commission (AEC) in Japan formulated the Third Phase Basic Program so as to promote an experimental fusion reactor project. In 2005 AEC has reviewed this Program, and discussed on selection and concentration among many projects of fusion reactor development. In addition to the promotion of ITER project, advanced tokamak research by JT-60SA, helical plasma experiment by LHD, FIREX project in laser fusion research and fusion engineering by IFMIF were highly prioritized. Although the basic concept is quite different between tokamak, helical and laser fusion researches, there exist a lot of common features such as plasma physics on 3-D magnetic geometry, high power heat load on plasma facing component and so on. Therefore, a synergetic scenario on fusion reactor development among various plasma confinement concepts would be important.

Resonantly pumped high efficiency Ho:YAG laser.

PubMed

Shen, Ying-Jie; Yao, Bao-Quan; Duan, Xiao-Ming; Dai, Tong-Yu; Ju, You-Lun; Wang, Yue-Zhu

2012-11-20

High-efficient CW and Q-switched Ho:YAG lasers resonantly dual-end-pumped by two diode-pumped Tm:YLF lasers at 1908 nm were investigated. A maximum slope efficiency of 74.8% in CW operation as well as a maximum output power of 58.7 W at 83.2 W incident pump power was achieved, which corresponded to an optical-to-optical conversion efficiency of 70.6%. The maximum pulse energy of 2.94 mJ was achieved, with a 31 ns FWHM pulse width and a peak power of approximately 94.7 kW.

Design of High Efficiency High Power Electron Accelerator Systems Based on Normal Conducting RF Technology for Energy and Environmental Applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dolgashev, Valery; Tantawi, Sami

The goal of this project was to perform engineering design studies of three extremely high efficiency electron accelerators with the following parameters [1]: 2 MeV output beam energy and 1 MW average beam power; 10 MeV output energy and 10 MW; 10 MeV output energy and 1 MW. These linacs are intended for energy and environmental applications [2]. We based our designs on normal conducting radio-frequency technology. We have successfully reached this goal where we show rf-to-beam efficiency of 96.7 %, 97.2 %, and 79.6 % for these linacs.

Laser driven nuclear science and applications: The need of high efficiency, high power and high repetition rate Laser beams

NASA Astrophysics Data System (ADS)

Gales, S.

2015-10-01

Extreme Light Infrastructure (ELI) is a pan European research initiative selected on the European Strategy Forum on Research Infrastructures Roadmap that aims to close the gap between the existing laboratory-based laser driven research and international facility-grade research centre. The ELI-NP facility, one of the three ELI pillars under construction, placed in Romania and to be operational in 2018, has as core elements a couple of new generation 10 PW laser systems and a narrow bandwidth Compton backscattering gamma source with photon energies up to 19 MeV. ELI-NP will address nuclear photonics, nuclear astrophysics and quantum electrodynamics involving extreme photon fields. Prospective applications of high power laser in nuclear astrophysics, accelerator physics, in particular towards future Accelerator Driven System, as well as in nuclear photonics, for detection and characterization of nuclear material, and for nuclear medicine, will be discussed. Key issues in these research areas will be at reach with significant increase of the repetition rates and of the efficiency at the plug of the high power laser systems as proposed by the ICAN collaboration.

High density operation for reactor-relevant power exhaust

NASA Astrophysics Data System (ADS)

Wischmeier, M.; ASDEX Upgrade Team; Jet Efda Contributors

2015-08-01

With increasing size of a tokamak device and associated fusion power gain an increasing power flux density towards the divertor needs to be handled. A solution for handling this power flux is crucial for a safe and economic operation. Using purely geometric arguments in an ITER-like divertor this power flux can be reduced by approximately a factor 100. Based on a conservative extrapolation of current technology for an integrated engineering approach to remove power deposited on plasma facing components a further reduction of the power flux density via volumetric processes in the plasma by up to a factor of 50 is required. Our current ability to interpret existing power exhaust scenarios using numerical transport codes is analyzed and an operational scenario as a potential solution for ITER like divertors under high density and highly radiating reactor-relevant conditions is presented. Alternative concepts for risk mitigation as well as strategies for moving forward are outlined.

Power-efficient dual-rate optical transceiver.

PubMed

Zuo, Yongrong; Kiamiley, Fouad E; Wang, Xiaoqing; Gui, Ping; Ekman, Jeremy; Wang, Xingle; McFadden, Michael J; Haney, Michael W

2005-11-20

A dual-rate (2 Gbit/s and 100 Mbit/s) optical transceiver designed for power-efficient connections within and between modern high-speed digital systems is described. The transceiver can dynamically adjust its data rate according to performance requirements, allowing for power-on-demand operation. Dynamic power management permits energy saving and lowers device operating temperatures, improving the reliability and lifetime of optoelectronic-devices such as vertical-cavity surface-emitting lasers (VCSELs). To implement dual-rate functionality, we include in the transmitter and receiver circuits separate high-speed and low-power data path modules. The high-speed module is designed for gigabit operation to achieve high bandwidth. A simpler low-power module is designed for megabit data transmission with low power consumption. The transceiver is fabricated in a 0.5 microm silicon-on-sapphire complementary metal-oxide semiconductor. The VCSEL and photodetector devices are attached to the transceiver's integrated circuit by flip-chip bonding. A free-space optical link system is constructed to demonstrate correct dual-rate functionality. Experimental results show reliable link operation at 2 Gbit/s and 100 Mbit/s data transfer rates with approximately 104 and approximately 9 mW power consumption, respectively. The transceiver's switching time between these two data rates is demonstrated as 10 micros, which is limited by on-chip register reconfiguration time. Improvement of this switching time can be obtained by use of dedicated input-output pads for dual-rate control signals.

High Efficiency GPS Block III L1 band Envelope Tracking Power Amplifier

DTIC Science & Technology

2016-03-31

intermo asymmetric ri nction and is d 30.69MHz w measured with pe Amplifier e CGH40120F Sub-System: F e RFPA and E Fig. 7: Nati The switcher the...Paul T. The Efficiency W ack Power Am Dongsu Ki Bumman, "Hi lator for Enve ess Componen Hassan, M. ing power-sup z LTE Envelop ts Conference

Electrode architectures for efficient electronic and ionic transport pathways in high power lithium ion batteries

NASA Astrophysics Data System (ADS)

Faulkner, Ankita Shah

As the demand for clean energy sources increases, large investments have supported R&D programs aimed at developing high power lithium ion batteries for electric vehicles, military, grid storage and space applications. State of the art lithium ion technology cannot meet power demands for these applications due to high internal resistances in the cell. These resistances are mainly comprised of ionic and electronic resistance in the electrode and electrolyte. Recently, much attention has been focused on the use of nanoscale lithium ion active materials on the premise that these materials shorten the diffusion length of lithium ions and increase the surface area for electrochemical charge transfer. While, nanomaterials have allowed significant improvements in the power density of the cell, they are not a complete solution for commercial batteries. Due to their large surface area, they introduce new challenges such as a poor electrode packing densities, high electrolyte reactivity, and expensive synthesis procedures. Since greater than 70% of the cost of the electric vehicle is due to the cost of the battery, a cost-efficient battery design is most critical. To address the limitations of nanomaterials, efficient transport pathways must be engineered in the bulk electrode. As a part of nanomanufacturing research being conducted the Center for High-rate Nanomanufacturing at Northeastern University, the first aim of the proposed work is to develop electrode architectures that enhance electronic and ionic transport pathways in large and small area lithium ion electrodes. These architectures will utilize the unique electronic and mechanical properties of carbon nanotubes to create robust electrode scaffolding that improves electrochemical charge transfer. Using extensive physical and electrochemical characterization, the second aim is to investigate the effect of electrode parameters on electrochemical performance and evaluate the performance against standard commercial

Weldability of Advanced High Strength Steels using Ytterbium:Yttrium Aluminium Garnet high power laser for Tailor-Welded Blank applications

NASA Astrophysics Data System (ADS)

Sharma, Rajashekhar Shivaram

transverse direction were evaluated. Metallographic examinations determined that most of the fusion zone is martensitic with small regions of bainite and ferrite. High microhardness values of the order of 550--600 Hv were noted in most joints, which are attributed to high alloy content of the fusion zone as well as high rates of cooling typical of laser welds. During tensile, fatigue and formability tests, no fractures in the fusion or heat affected zones were observed. Geometric variability evaluations indicated that coatings such as aluminum (in the case of USIBOR) and galvanized zinc (TRIP780) can affect the variability of the weld zone and the surface roughness on the top of the weld. Excessive variability in the form of weld concavity in the weld zones can lead to fractures in the weld region, even though higher hardness can, to some extent, compensate for these surface irregularities. The 2-factor design of experiments further confirmed that coatings adversely affect the surface roughness on the top of the welds. Although thickness differentials alone do not make a significant impact on surface roughness, together with coatings, they can have an adverse effect on roughness. Tensile tests in the direction of rolling as well as in the transverse direction indicate that TRIP780 seems weaker in the direction of rolling when compared to transverse direction while mild steel is stronger in the direction of rolling. Weldability analyses revealed that the typical melting efficiency is on the order of 50--70% for full penetration welding. Formability tests showed that TR/MS joints fractured in a direction parallel to the weld line when tested with the loads perpendicular to the weld line. Tests have also confirmed that weld speed and power have no impact on the outcome of formability results. Overall, this work conclusively proves that high power Yb:YAG lasers can effectively join high strength materials such as DP980, TRIP780, USIBOR, as well as mild steel, for use in tailor

Advantages of Production of New Fissionable Nuclides for the Nuclear Power Industry in Hybrid Fusion-Fission Reactors

NASA Astrophysics Data System (ADS)

Tsibulskiy, V. F.; Andrianova, E. A.; Davidenko, V. D.; Rodionova, E. V.; Tsibulskiy, S. V.

2017-12-01

A concept of a large-scale nuclear power engineering system equipped with fusion and fission reactors is presented. The reactors have a joint fuel cycle, which imposes the lowest risk of the radiation impact on the environment. The formation of such a system is considered within the framework of the evolution of the current nuclear power industry with the dominance of thermal reactors, gradual transition to the thorium fuel cycle, and integration into the system of the hybrid fusion-fission reactors for breeding nuclear fuel for fission reactors. Such evolution of the nuclear power engineering system will allow preservation of the existing structure with the dominance of thermal reactors, enable the reprocessing of the spent nuclear fuel (SNF) with low burnup, and prevent the dangerous accumulation of minor actinides. The proposed structure of the nuclear power engineering system minimizes the risk of radioactive contamination of the environment and the SNF reprocessing facilities, decreasing it by more than one order of magnitude in comparison with the proposed scheme of closing the uranium-plutonium fuel cycle based on the reprocessing of SNF with high burnup from fast reactors.

Fusion Propulsion Z-Pinch Engine Concept

NASA Technical Reports Server (NTRS)

Miernik, J.; Statham, G.; Fabisinski, L.; Maples, C. D.; Adams, R.; Polsgrove, T.; Fincher, S.; Cassibry, J.; Cortez, R.; Turner, M.;

Commercial objectives, technology transfer, and systems analysis for fusion power development

NASA Astrophysics Data System (ADS)

Dean, Stephen O.

1988-09-01

Fusion is an inexhaustible source of energy that has the potential for economic commercial applications with excellent safety and environmental characteristics. The primary focus for the fusion energy development program is the generation of central station electricity. Fusion has the potential, however, for many other applications. The fact that a large fraction of the energy released in a DT fusion reaction is carried by high energy neutrons suggests potentially unique applications. In addition, fusion R and D will lead to new products and new markets. Each fusion application must meet certain standards of economic and safety and environmental attractiveness. For this reason, economics on the one hand, and safety and environment and licensing on the other, are the two primary criteria for setting long range commercial fusion objectives. A major function of systems analysis is to evaluate the potential of fusion against these objectives and to help guide the fusion R and D program toward practical applications. The transfer of fusion technology and skills from the national labs and universities to industry is the key to achieving the long range objective of commercial fusion applications.

Commercial objectives, technology transfer, and systems analysis for fusion power development

NASA Technical Reports Server (NTRS)

Dean, Stephen O.

1988-01-01

Fusion is an inexhaustible source of energy that has the potential for economic commercial applications with excellent safety and environmental characteristics. The primary focus for the fusion energy development program is the generation of central station electricity. Fusion has the potential, however, for many other applications. The fact that a large fraction of the energy released in a DT fusion reaction is carried by high energy neutrons suggests potentially unique applications. In addition, fusion R and D will lead to new products and new markets. Each fusion application must meet certain standards of economic and safety and environmental attractiveness. For this reason, economics on the one hand, and safety and environment and licensing on the other, are the two primary criteria for setting long range commercial fusion objectives. A major function of systems analysis is to evaluate the potential of fusion against these objectives and to help guide the fusion R and D program toward practical applications. The transfer of fusion technology and skills from the national labs and universities to industry is the key to achieving the long range objective of commercial fusion applications.

High-efficiency, broad band, high-damage threshold high-index gratings for femtosecond pulse compression.

PubMed

Canova, Frederico; Clady, Raphael; Chambaret, Jean-Paul; Flury, Manuel; Tonchev, Svtelen; Fechner, Renate; Parriaux, Olivier

2007-11-12

High efficiency, broad-band TE-polarization diffraction over a wavelength range centered at 800 nm is obtained by high index gratings placed on a non-corrugated mirror. More than 96% efficiency wide band top-hat diffraction efficiency spectra, as well as more than 1 J/cm(2) damage threshold under 50 fs pulses are demonstrated experimentally. This opens the way to high-efficiency Chirped Pulse Amplification for high average power laser machining by means of all-dielectric structures as well as for ultra-short high energy pulses by means of metal-dielectric structures.

Magnetized Target Fusion Driven by Plasma Liners

NASA Technical Reports Server (NTRS)

Thio, Y. C. Francis; Kirkpatrick, Ronald C.; Knapp, Charles E.; Rodgers, Stephen L. (Technical Monitor)

2002-01-01

Magnetized target fusion is an emerging, relatively unexplored approach to fusion for electrical power and propulsion application. The physical principles of the concept are founded upon both inertial confinement fusion (ICF) and magnetic confinement fusion (MCF). It attempts to combine the favorable attributes of both these orthogonal approaches to fusion, but at the same time, avoiding the extreme technical challenges of both by exploiting a fusion regime intermediate between them. It uses a material liner to compress, heat and contain the fusion reacting plasma (the target plasma) mentally. By doing so, the fusion burn could be made to occur at plasma densities as high as six orders of magnitude higher than conventional MCF such as tokamak, thus leading to an approximately three orders of magnitude reduction in the plasma energy required for ignition. It also uses a transient magnetic field, compressed to extremely high intensity (100's T to 1000T) in the target plasma, to slow down the heat transport to the liner and to increase the energy deposition of charged-particle fusion products. This has several compounding beneficial effects. It leads to longer energy confinement time compared with conventional ICF without magnetized target, and thus permits the use of much lower plasma density to produce reasonable burn-up fraction. The compounding effects of lower plasma density and the magneto-insulation of the target lead to greatly reduced compressional heating power on the target. The increased energy deposition rate of charged-particle fusion products also helps to lower the energy threshold required for ignition and increasing the burn-up fraction. The reduction in ignition energy and the compressional power compound to lead to reduced system size, mass and R&D cost. It is a fusion approach that has an affordable R&D pathway, and appears attractive for propulsion application in the nearer term.

Development of high frequency low weight power magnetics for aerospace power systems

NASA Technical Reports Server (NTRS)

Schwarze, G. E.

1984-01-01

A dominant design consideration in the development of space type power mangetic devices is the application of reliable thermal control methods to prevent device failure which is due to excessive temperature rises and hot temperatures in critical areas. The resultant design must also yield low weight, high efficiency, high reliability and maintainability, and long life. The weight savings and high efficiency that results by going to high frequency and unique thermal control techniques is demonstrated by the development of a 25 kVA, 20 kHz space type transformer under the power magnetics technology program. Work in the area of power rotary transformer is also discussed.

High-energy krypton fluoride lasers for inertial fusion.

PubMed

Obenschain, Stephen; Lehmberg, Robert; Kehne, David; Hegeler, Frank; Wolford, Matthew; Sethian, John; Weaver, James; Karasik, Max

2015-11-01

Laser fusion researchers have realized since the 1970s that the deep UV light from excimer lasers would be an advantage as a driver for robust high-performance capsule implosions for inertial confinement fusion (ICF). Most of this research has centered on the krypton-fluoride (KrF) laser. In this article we review the advantages of the KrF laser for direct-drive ICF, the history of high-energy KrF laser development, and the present state of the art and describe a development path to the performance needed for laser fusion and its energy application. We include descriptions of the architecture and performance of the multi-kilojoule Nike KrF laser-target facility and the 700 J Electra high-repetition-rate KrF laser that were developed at the U.S. Naval Research Laboratory. Nike and Electra are the most advanced KrF lasers for inertial fusion research and energy applications.

Lead (Pb) Hohlraum: Target for Inertial Fusion Energy

PubMed Central

Ross, J. S.; Amendt, P.; Atherton, L. J.; Dunne, M.; Glenzer, S. H.; Lindl, J. D.; Meeker, D.; Moses, E. I.; Nikroo, A.; Wallace, R.

2013-01-01

Recent progress towards demonstrating inertial confinement fusion (ICF) ignition at the National Ignition Facility (NIF) has sparked wide interest in Laser Inertial Fusion Energy (LIFE) for carbon-free large-scale power generation. A LIFE-based fleet of power plants promises clean energy generation with no greenhouse gas emissions and a virtually limitless, widely available thermonuclear fuel source. For the LIFE concept to be viable, target costs must be minimized while the target material efficiency or x-ray albedo is optimized. Current ICF targets on the NIF utilize a gold or depleted uranium cylindrical radiation cavity (hohlraum) with a plastic capsule at the center that contains the deuterium and tritium fuel. Here we show a direct comparison of gold and lead hohlraums in efficiently ablating deuterium-filled plastic capsules with soft x rays. We report on lead hohlraum performance that is indistinguishable from gold, yet costing only a small fraction. PMID:23486285

Lead (Pb) hohlraum: target for inertial fusion energy.

PubMed

Ross, J S; Amendt, P; Atherton, L J; Dunne, M; Glenzer, S H; Lindl, J D; Meeker, D; Moses, E I; Nikroo, A; Wallace, R

2013-01-01

Recent progress towards demonstrating inertial confinement fusion (ICF) ignition at the National Ignition Facility (NIF) has sparked wide interest in Laser Inertial Fusion Energy (LIFE) for carbon-free large-scale power generation. A LIFE-based fleet of power plants promises clean energy generation with no greenhouse gas emissions and a virtually limitless, widely available thermonuclear fuel source. For the LIFE concept to be viable, target costs must be minimized while the target material efficiency or x-ray albedo is optimized. Current ICF targets on the NIF utilize a gold or depleted uranium cylindrical radiation cavity (hohlraum) with a plastic capsule at the center that contains the deuterium and tritium fuel. Here we show a direct comparison of gold and lead hohlraums in efficiently ablating deuterium-filled plastic capsules with soft x rays. We report on lead hohlraum performance that is indistinguishable from gold, yet costing only a small fraction.

Highly Efficient Wireless Powering for Autonomous Structural Health Monitoring and Test/Evaluation Systems

DTIC Science & Technology

2016-07-27

ADDRESS (ES) U.S. Army Research Office P.O. Box 12211 Research Triangle Park, NC 27709-2211 Wireless Power Transfer , Structural Health Monitoring...efficient strongly coupled magnetic resonant systems, Wireless Power Transfer , (03 2014): 0. doi: 10.1017/wpt.2014.3 TOTAL: 1 Received Paper TOTAL...2016 Received Paper . Miniaturized Strongly Coupled Magnetic Resonant Systems for Wireless Power Transfer , 2016 IEEE Antennas Propagat. Society

Multi-Kilowatt Power Module for High-Power Hall Thrusters

NASA Technical Reports Server (NTRS)

Pinero, Luis R.; Bowers, Glen E.

2005-01-01

Future NASA missions will require high-performance electric propulsion systems. Hall thrusters are being developed at NASA Glenn for high-power, high-specific impulse operation. These thrusters operate at power levels up to 50 kW of power and discharge voltages in excess of 600 V. A parallel effort is being conducted to develop power electronics for these thrusters that push the technology beyond the 5kW state-of-the-art power level. A 10 kW power module was designed to produce an output of 500 V and 20 A from a nominal 100 V input. Resistive load tests revealed efficiencies in excess of 96 percent. Load current share and phase synchronization circuits were designed and tested that will allow connecting multiple modules in parallel to process higher power.

ELIPS: Toward a Sensor Fusion Processor on a Chip

NASA Technical Reports Server (NTRS)

Daud, Taher; Stoica, Adrian; Tyson, Thomas; Li, Wei-te; Fabunmi, James

1998-01-01

The paper presents the concept and initial tests from the hardware implementation of a low-power, high-speed reconfigurable sensor fusion processor. The Extended Logic Intelligent Processing System (ELIPS) processor is developed to seamlessly combine rule-based systems, fuzzy logic, and neural networks to achieve parallel fusion of sensor in compact low power VLSI. The first demonstration of the ELIPS concept targets interceptor functionality; other applications, mainly in robotics and autonomous systems are considered for the future. The main assumption behind ELIPS is that fuzzy, rule-based and neural forms of computation can serve as the main primitives of an "intelligent" processor. Thus, in the same way classic processors are designed to optimize the hardware implementation of a set of fundamental operations, ELIPS is developed as an efficient implementation of computational intelligence primitives, and relies on a set of fuzzy set, fuzzy inference and neural modules, built in programmable analog hardware. The hardware programmability allows the processor to reconfigure into different machines, taking the most efficient hardware implementation during each phase of information processing. Following software demonstrations on several interceptor data, three important ELIPS building blocks (a fuzzy set preprocessor, a rule-based fuzzy system and a neural network) have been fabricated in analog VLSI hardware and demonstrated microsecond-processing times.

Theoretical z -pinch scaling relations for thermonuclear-fusion experiments.

PubMed

Stygar, W A; Cuneo, M E; Vesey, R A; Ives, H C; Mazarakis, M G; Chandler, G A; Fehl, D L; Leeper, R J; Matzen, M K; McDaniel, D H; McGurn, J S; McKenney, J L; Muron, D J; Olson, C L; Porter, J L; Ramirez, J J; Seamen, J F; Speas, C S; Spielman, R B; Struve, K W; Torres, J A; Waisman, E M; Wagoner, T C; Gilliland, T L

2005-08-01

We have developed wire-array z -pinch scaling relations for plasma-physics and inertial-confinement-fusion (ICF) experiments. The relations can be applied to the design of z -pinch accelerators for high-fusion-yield (approximately 0.4 GJ/shot) and inertial-fusion-energy (approximately 3 GJ/shot) research. We find that (delta(a)/delta(RT)) proportional (m/l)1/4 (Rgamma)(-1/2), where delta(a) is the imploding-sheath thickness of a wire-ablation-dominated pinch, delta(RT) is the sheath thickness of a Rayleigh-Taylor-dominated pinch, m is the total wire-array mass, l is the axial length of the array, R is the initial array radius, and gamma is a dimensionless functional of the shape of the current pulse that drives the pinch implosion. When the product Rgamma is held constant the sheath thickness is, at sufficiently large values of m/l, determined primarily by wire ablation. For an ablation-dominated pinch, we estimate that the peak radiated x-ray power P(r) proportional (I/tau(i))(3/2)Rlphigamma, where I is the peak pinch current, tau(i) is the pinch implosion time, and phi is a dimensionless functional of the current-pulse shape. This scaling relation is consistent with experiment when 13 MA < or = I < or = 20 MA, 93 ns < or = tau(i) < or = 169 ns, 10 mm < or = R < or = 20 mm, 10 mm < or = l < or = 20 mm, and 2.0 mg/cm < or = m/l < or = 7.3 mg/cm. Assuming an ablation-dominated pinch and that Rlphigamma is held constant, we find that the x-ray-power efficiency eta(x) congruent to P(r)/P(a) of a coupled pinch-accelerator system is proportional to (tau(i)P(r)(7/9 ))(-1), where P(a) is the peak accelerator power. The pinch current and accelerator power required to achieve a given value of P(r) are proportional to tau(i), and the requisite accelerator energy E(a) is proportional to tau2(i). These results suggest that the performance of an ablation-dominated pinch, and the efficiency of a coupled pinch-accelerator system, can be improved substantially by decreasing the

Power and Efficiency Optimized in Traveling-Wave Tubes Over a Broad Frequency Bandwidth

NASA Technical Reports Server (NTRS)

Wilson, Jeffrey D.

2001-01-01

A traveling-wave tube (TWT) is an electron beam device that is used to amplify electromagnetic communication waves at radio and microwave frequencies. TWT's are critical components in deep space probes, communication satellites, and high-power radar systems. Power conversion efficiency is of paramount importance for TWT's employed in deep space probes and communication satellites. A previous effort was very successful in increasing efficiency and power at a single frequency (ref. 1). Such an algorithm is sufficient for narrow bandwidth designs, but for optimal designs in applications that require high radiofrequency power over a wide bandwidth, such as high-density communications or high-resolution radar, the variation of the circuit response with respect to frequency must be considered. This work at the NASA Glenn Research Center is the first to develop techniques for optimizing TWT efficiency and output power over a broad frequency bandwidth (ref. 2). The techniques are based on simulated annealing, which has the advantage over conventional optimization techniques in that it enables the best possible solution to be obtained (ref. 3). Two new broadband simulated annealing algorithms were developed that optimize (1) minimum saturated power efficiency over a frequency bandwidth and (2) simultaneous bandwidth and minimum power efficiency over the frequency band with constant input power. The algorithms were incorporated into the NASA coupled-cavity TWT computer model (ref. 4) and used to design optimal phase velocity tapers using the 59- to 64-GHz Hughes 961HA coupled-cavity TWT as a baseline model. In comparison to the baseline design, the computational results of the first broad-band design algorithm show an improvement of 73.9 percent in minimum saturated efficiency (see the top graph). The second broadband design algorithm (see the bottom graph) improves minimum radiofrequency efficiency with constant input power drive by a factor of 2.7 at the high band edge (64

Silicon-Carbide Power MOSFET Performance in High Efficiency Boost Power Processing Unit for Extreme Environments

NASA Technical Reports Server (NTRS)

Ikpe, Stanley A.; Lauenstein, Jean-Marie; Carr, Gregory A.; Hunter, Don; Ludwig, Lawrence L.; Wood, William; Del Castillo, Linda Y.; Fitzpatrick, Fred; Chen, Yuan

2016-01-01

Silicon-Carbide device technology has generated much interest in recent years. With superior thermal performance, power ratings and potential switching frequencies over its Silicon counterpart, Silicon-Carbide offers a greater possibility for high powered switching applications in extreme environment. In particular, Silicon-Carbide Metal-Oxide- Semiconductor Field-Effect Transistors' (MOSFETs) maturing process technology has produced a plethora of commercially available power dense, low on-state resistance devices capable of switching at high frequencies. A novel hard-switched power processing unit (PPU) is implemented utilizing Silicon-Carbide power devices. Accelerated life data is captured and assessed in conjunction with a damage accumulation model of gate oxide and drain-source junction lifetime to evaluate potential system performance at high temperature environments.

A fission-fusion hybrid reactor in steady-state L-mode tokamak configuration with natural uranium

DOE Office of Scientific and Technical Information (OSTI.GOV)

Reed, Mark; Parker, Ronald R.; Forget, Benoit

2012-06-19

This work develops a conceptual design for a fusion-fission hybrid reactor operating in steady-state L-mode tokamak configuration with a subcritical natural or depleted uranium pebble bed blanket. A liquid lithium-lead alloy breeds enough tritium to replenish that consumed by the D-T fusion reaction. The fission blanket augments the fusion power such that the fusion core itself need not have a high power gain, thus allowing for fully non-inductive (steady-state) low confinement mode (L-mode) operation at relatively small physical dimensions. A neutron transport Monte Carlo code models the natural uranium fission blanket. Maximizing the fission power gain while breeding sufficient tritiummore » allows for the selection of an optimal set of blanket parameters, which yields a maximum prudent fission power gain of approximately 7. A 0-D tokamak model suffices to analyze approximate tokamak operating conditions. This fission blanket would allow the fusion component of a hybrid reactor with the same dimensions as ITER to operate in steady-state L-mode very comfortably with a fusion power gain of 6.7 and a thermal fusion power of 2.1 GW. Taking this further can determine the approximate minimum scale for a steady-state L-mode tokamak hybrid reactor, which is a major radius of 5.2 m and an aspect ratio of 2.8. This minimum scale device operates barely within the steady-state L-mode realm with a thermal fusion power of 1.7 GW. Basic thermal hydraulic analysis demonstrates that pressurized helium could cool the pebble bed fission blanket with a flow rate below 10 m/s. The Brayton cycle thermal efficiency is 41%. This reactor, dubbed the Steady-state L-mode non-Enriched Uranium Tokamak Hybrid (SLEUTH), with its very fast neutron spectrum, could be superior to pure fission reactors in terms of breeding fissile fuel and transmuting deleterious fission products. It would likely function best as a prolific plutonium breeder, and the plutonium it produces could actually be more

A fission-fusion hybrid reactor in steady-state L-mode tokamak configuration with natural uranium

NASA Astrophysics Data System (ADS)

Reed, Mark; Parker, Ronald R.; Forget, Benoit

2012-06-01

This work develops a conceptual design for a fusion-fission hybrid reactor operating in steady-state L-mode tokamak configuration with a subcritical natural or depleted uranium pebble bed blanket. A liquid lithium-lead alloy breeds enough tritium to replenish that consumed by the D-T fusion reaction. The fission blanket augments the fusion power such that the fusion core itself need not have a high power gain, thus allowing for fully non-inductive (steady-state) low confinement mode (L-mode) operation at relatively small physical dimensions. A neutron transport Monte Carlo code models the natural uranium fission blanket. Maximizing the fission power gain while breeding sufficient tritium allows for the selection of an optimal set of blanket parameters, which yields a maximum prudent fission power gain of approximately 7. A 0-D tokamak model suffices to analyze approximate tokamak operating conditions. This fission blanket would allow the fusion component of a hybrid reactor with the same dimensions as ITER to operate in steady-state L-mode very comfortably with a fusion power gain of 6.7 and a thermal fusion power of 2.1 GW. Taking this further can determine the approximate minimum scale for a steady-state L-mode tokamak hybrid reactor, which is a major radius of 5.2 m and an aspect ratio of 2.8. This minimum scale device operates barely within the steady-state L-mode realm with a thermal fusion power of 1.7 GW. Basic thermal hydraulic analysis demonstrates that pressurized helium could cool the pebble bed fission blanket with a flow rate below 10 m/s. The Brayton cycle thermal efficiency is 41%. This reactor, dubbed the Steady-state L-mode non-Enriched Uranium Tokamak Hybrid (SLEUTH), with its very fast neutron spectrum, could be superior to pure fission reactors in terms of breeding fissile fuel and transmuting deleterious fission products. It would likely function best as a prolific plutonium breeder, and the plutonium it produces could actually be more

Modeling of high efficiency solar cells under laser pulse for power beaming applications

NASA Technical Reports Server (NTRS)

Jain, Raj K.; Landis, Geoffrey A.

1994-01-01

Solar cells have been used to convert sunlight to electrical energy for many years and also offer great potential for non-solar energy conversion applications. Their greatly improved performance under monochromatic light compared to sunlight, makes them suitable as photovoltaic (PV) receivers in laser power beaming applications. Laser beamed power to a PV array receiver could provide power to satellites, an orbital transfer vehicle, or a lunar base. Gallium arsenide (GaAs) and indium phosphide (InP) solar cells have calculated efficiencies of more than 50 percent under continuous illumination at the optimum wavelength. Currently high power free-electron lasers are being developed which operate in pulsed conditions. Understanding cell behavior under a laser pulse is important in the selection of the solar cell material and the laser. An experiment by NAsA lewis and JPL at the AVLIS laser facility in Livermore, CA presented experimental data on cell performance under pulsed laser illumination. Reference 5 contains an overview of technical issues concerning the use of solar cells for laser power conversion, written before the experiments were performed. As the experimental results showed, the actual effects of pulsed operation are more complicated. Reference 6 discusses simulations of the output of GaAs concentrator solar cells under pulsed laser illumination. The present paper continues this work, and compares the output of Si and GaAs solar cells.

High Efficiency Turbine Generator for Instream Electric Power Production

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kelecy, Patrick M.

Concerns over global warming due to carbon emissions have spurred an interest in such renewable energy alternatives as hydroelectric, wind, solar, geothermal, and biomass. Of all of these, hydroelectric power offers perhaps the greatest potential for supplying a significant portion of our nation's energy needs. To realize this potential, however, this technology needs to expand beyond traditional dam based installations (for which there are relatively few suitable remaining sites) into the vast number of open flow installations potentially available in rivers, canals, tidal streams and open ocean sites. To help promote this expansion, this project focused on the development ofmore » an advanced, vertical axis, hydrokinetic power generator (HPG) technology for open flow applications. Two key features investigated for this were (1) an active blade pitch control system that provides independent control of the turbine blades, and (2) a low-profile, low-speed, high-torque electric generator suitable for direct coupling to the turbine (no gearbox). Both systems are based on a unique, disk-shape, high performance electromechanical design that is potentially low cost, compact, light-weight, and efficient. Blade actuator and generator designs were developed and optimized for this application. They were then incorporated into several HPG designs based on an optimized H-Darrieus turbine structure that was also developed. Three HPG sizes were explored (10kW, 25kW and 50kW) to assess scalability. For each size, two HPG versions were developed: one with the electric generator mounted above the turbine and one with it integrated into the turbine body. Each provided certain benefits and illustrated the versatility of this technology. Design and performance specifications were calculated and comparisons were made with commercial hydrokinetic turbine products. Based on these comparisons, this technology was smaller and significantly lighter (by up to 50%) in the higher power

Method and apparatus to produce high specific impulse and moderate thrust from a fusion-powered rocket engine

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cohen, Samuel A.; Pajer, Gary A.; Paluszek, Michael A.

A system and method for producing and controlling high thrust and desirable specific impulse from a continuous fusion reaction is disclosed. The resultant relatively small rocket engine will have lower cost to develop, test, and operate that the prior art, allowing spacecraft missions throughout the planetary system and beyond. The rocket engine method and system includes a reactor chamber and a heating system for heating a stable plasma to produce fusion reactions in the stable plasma. Magnets produce a magnetic field that confines the stable plasma. A fuel injection system and a propellant injection system are included. The propellant injectionmore » system injects cold propellant into a gas box at one end of the reactor chamber, where the propellant is ionized into a plasma. The propellant and fusion products are directed out of the reactor chamber through a magnetic nozzle and are detached from the magnetic field lines producing thrust.« less

Modelling the power deposition into a spherical tokamak fusion power plant

NASA Astrophysics Data System (ADS)

Windsor, C. G.; Morgan, J. G.; Buxton, P. F.; Costley, A. E.; Smith, G. D. W.; Sykes, A.

2017-03-01

Numerical studies have been made to improve the performance of the central column of a superconducting spherical tokamak fusion pilot plant. The assumed neutron shield includes concentric layers of tungsten carbide and water. The relative thickness of the water layers was varied and a minimum power deposition was found at about 17% of water. It was found advantageous to have an approximately 1.7 times thicker water layer next to the core and a similarly thinner layer next to the plasma. The use of tungsten boride instead of tungsten carbide was shown to make an improvement especially if placed close to the central superconducting core, the inner layer alone reducing the power deposition by 29%. Engineering features such as a central steel tie-bar, an insulating thermal vacuum gap, a wall gap next to the plasma and knowledge of the vertical energy distribution are essential to a successful design and their effects on the power deposition are shown in an appendix. The results have been fitted to model distributions and incorporated into the Tokamak Energy System Code, which can then give predictions of the power deposition as a function of other parameters such as the plasma major radius and the maximum magnetic field permitted on the superconductors.

CMOS Amperometric ADC With High Sensitivity, Dynamic Range and Power Efficiency for Air Quality Monitoring.

PubMed

Li, Haitao; Boling, C Sam; Mason, Andrew J

2016-08-01

Airborne pollutants are a leading cause of illness and mortality globally. Electrochemical gas sensors show great promise for personal air quality monitoring to address this worldwide health crisis. However, implementing miniaturized arrays of such sensors demands high performance instrumentation circuits that simultaneously meet challenging power, area, sensitivity, noise and dynamic range goals. This paper presents a new multi-channel CMOS amperometric ADC featuring pixel-level architecture for gas sensor arrays. The circuit combines digital modulation of input currents and an incremental Σ∆ ADC to achieve wide dynamic range and high sensitivity with very high power efficiency and compact size. Fabricated in 0.5 [Formula: see text] CMOS, the circuit was measured to have 164 dB cross-scale dynamic range, 100 fA sensitivity while consuming only 241 [Formula: see text] and 0.157 [Formula: see text] active area per channel. Electrochemical experiments with liquid and gas targets demonstrate the circuit's real-time response to a wide range of analyte concentrations.

Switching coordination of distributed dc-dc converters for highly efficient photovoltaic power plants

DOEpatents

Agamy, Mohammed; Elasser, Ahmed; Sabate, Juan Antonio; Galbraith, Anthony William; Harfman Todorovic, Maja

2014-09-09

A distributed photovoltaic (PV) power plant includes a plurality of distributed dc-dc converters. The dc-dc converters are configured to switch in coordination with one another such that at least one dc-dc converter transfers power to a common dc-bus based upon the total system power available from one or more corresponding strings of PV modules. Due to the coordinated switching of the dc-dc converters, each dc-dc converter transferring power to the common dc-bus continues to operate within its optimal efficiency range as well as to optimize the maximum power point tracking in order to increase the energy yield of the PV power plant.

Fusion for Space Propulsion and Plasma Liner Driven MTF

NASA Technical Reports Server (NTRS)

Thio, Y.C. Francis; Rodgers, Stephen L. (Technical Monitor)

2001-01-01

The need for fusion propulsion for interplanetary flights is discussed. For a propulsion system, there are three important system attributes: (1) The absolute amount of energy available, (2) the propellant exhaust velocity, and (3) the jet power per unit mass of the propulsion system (specific power). For human exploration and development of the solar system, propellant exhaust velocity in excess of 100 km/s and specific power in excess of 10 kW/kg are required. Chemical combustion cannot meet the requirement in propellant exhaust velocity. Nuclear fission processes typically result in producing energy in the form of heat that needs to be manipulated at temperatures limited by materials to about 2,800 K. Using the energy to heat a low atomic weight propellant cannot overcome the problem. Alternatively the energy can be converted into electricity which is then used to accelerate particles to high exhaust velocity. The necessary power conversion and conditioning equipment, however, increases the mass of the propulsion system for the same jet power by more than two orders of magnitude over chemical system, thus greatly limits the thrust-to-weight ratio attainable. If fusion can be developed, fusion appears to have the best of all worlds in terms of propulsion - it can provide the absolute amount, the propellant exhaust velocity, and the high specific jet power. An intermediate step towards pure fusion propulsion is a bimodal system in which a fission reactor is used to provide some of the energy to drive a fusion propulsion unit. The technical issues related to fusion for space propulsion are discussed. There are similarities as well as differences at the system level between applying fusion to propulsion and to terrestrial electrical power generation. The differences potentially provide a wider window of opportunities for applying fusion to propulsion. For example, pulsed approaches to fusion may be attractive for the propulsion application. This is particularly so

Performance study of highly efficient 520 W average power long pulse ceramic Nd:YAG rod laser

NASA Astrophysics Data System (ADS)

Choubey, Ambar; Vishwakarma, S. C.; Ali, Sabir; Jain, R. K.; Upadhyaya, B. N.; Oak, S. M.

2013-10-01

We report the performance study of a 2% atomic doped ceramic Nd:YAG rod for long pulse laser operation in the millisecond regime with pulse duration in the range of 0.5-20 ms. A maximum average output power of 520 W with 180 J maximum pulse energy has been achieved with a slope efficiency of 5.4% using a dual rod configuration, which is the highest for typical lamp pumped ceramic Nd:YAG lasers. The laser output characteristics of the ceramic Nd:YAG rod were revealed to be nearly equivalent or superior to those of high-quality single crystal Nd:YAG rod. The laser pump chamber and resonator were designed and optimized to achieve a high efficiency and good beam quality with a beam parameter product of 16 mm mrad (M2˜47). The laser output beam was efficiently coupled through a 400 μm core diameter optical fiber with 90% overall transmission efficiency. This ceramic Nd:YAG laser will be useful for various material processing applications in industry.

High-Power Microwave Transmission and Mode Conversion Program

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vernon, Ronald J.

2015-08-14

This is a final technical report for a long term project to develop improved designs and design tools for the microwave hardware and components associated with the DOE Plasma Fusion Program. We have developed basic theory, software, fabrication techniques, and low-power measurement techniques for the design of microwave hardware associated gyrotrons, microwave mode converters and high-power microwave transmission lines. Specifically, in this report we discuss our work on designing quasi-optical mode converters for single and multiple frequencies, a new method for the analysis of perturbed-wall waveguide mode converters, perturbed-wall launcher design for TE0n mode gyrotrons, quasi-optical traveling-wave resonator design formore » high-power testing of microwave components, and possible improvements to the HSX microwave transmission line.« less

Flexible, highly efficient all-polymer solar cells

PubMed Central

Kim, Taesu; Kim, Jae-Han; Kang, Tae Eui; Lee, Changyeon; Kang, Hyunbum; Shin, Minkwan; Wang, Cheng; Ma, Biwu; Jeong, Unyong; Kim, Taek-Soo; Kim, Bumjoon J.

2015-01-01

All-polymer solar cells have shown great potential as flexible and portable power generators. These devices should offer good mechanical endurance with high power-conversion efficiency for viability in commercial applications. In this work, we develop highly efficient and mechanically robust all-polymer solar cells that are based on the PBDTTTPD polymer donor and the P(NDI2HD-T) polymer acceptor. These systems exhibit high power-conversion efficiency of 6.64%. Also, the proposed all-polymer solar cells have even better performance than the control polymer-fullerene devices with phenyl-C61-butyric acid methyl ester (PCBM) as the electron acceptor (6.12%). More importantly, our all-polymer solar cells exhibit dramatically enhanced strength and flexibility compared with polymer/PCBM devices, with 60- and 470-fold improvements in elongation at break and toughness, respectively. The superior mechanical properties of all-polymer solar cells afford greater tolerance to severe deformations than conventional polymer-fullerene solar cells, making them much better candidates for applications in flexible and portable devices. PMID:26449658

INFORM Lab: a testbed for high-level information fusion and resource management

NASA Astrophysics Data System (ADS)

Valin, Pierre; Guitouni, Adel; Bossé, Eloi; Wehn, Hans; Happe, Jens

2011-05-01

DRDC Valcartier and MDA have created an advanced simulation testbed for the purpose of evaluating the effectiveness of Network Enabled Operations in a Coastal Wide Area Surveillance situation, with algorithms provided by several universities. This INFORM Lab testbed allows experimenting with high-level distributed information fusion, dynamic resource management and configuration management, given multiple constraints on the resources and their communications networks. This paper describes the architecture of INFORM Lab, the essential concepts of goals and situation evidence, a selected set of algorithms for distributed information fusion and dynamic resource management, as well as auto-configurable information fusion architectures. The testbed provides general services which include a multilayer plug-and-play architecture, and a general multi-agent framework based on John Boyd's OODA loop. The testbed's performance is demonstrated on 2 types of scenarios/vignettes for 1) cooperative search-and-rescue efforts, and 2) a noncooperative smuggling scenario involving many target ships and various methods of deceit. For each mission, an appropriate subset of Canadian airborne and naval platforms are dispatched to collect situation evidence, which is fused, and then used to modify the platform trajectories for the most efficient collection of further situation evidence. These platforms are fusion nodes which obey a Command and Control node hierarchy.

Discourse, Power, and Knowledge in the Management of "Big Science": The Production of Consensus in a Nuclear Fusion Research Laboratory.

ERIC Educational Resources Information Center

Kinsella, William J.

1999-01-01

Extends a Foucauldian view of power/knowledge to the archetypical knowledge-intensive organization, the scientific research laboratory. Describes the discursive production of power/knowledge at the "big science" laboratory conducting nuclear fusion research and illuminates a critical incident in which the fusion research…

High-Efficiency Photovoltaic System Using Partially-Connected DC-DC Converter

NASA Astrophysics Data System (ADS)

Uno, Masatoshi; Kukita, Akio; Tanaka, Koji

Power conversion electronics for photovoltaic (PV) systems are desired to operate as efficiently as possible to exploit the power generated by PV modules. This paper proposes a novel PV system in which a dc-dc converter is partially connected to series-connected PV modules. The proposed system achieves high power-conversion efficiency by reducing the passing power and input/output voltages of the converter. The theoretical operating principle was experimentally validated. Resultant efficiency performances of the proposed and conventional systems demonstrated that the proposed system was more efficient in terms of power conversion though the identical converter was used for the both systems.

Design and characterization of a durable and highly efficient energy-harvesting electrochromic window

NASA Astrophysics Data System (ADS)

Amasawa, Eri

With the growing global energy demands, electrochromic window (ECW) technology has attracted great attention for its ability to reversibly change the transmittance of incoming light through applied moderate potential. While ECW has a great potential to conserve energy from lighting and air conditioning in buildings, ECW still consumes energy; ECW should be self-powered for further energy conservation. In this study, a new design of energy-harvesting electrochromic window (EH-ECW) based on fusion of two technologies, organic electrochromic window and dye-sensitized solar cell (DSSC) is presented. Unlike other self-powered smart windows such as photoelectrochromic device that only contains two states (i.e. closed circuit colored state and open circuit bleaching state), EH-ECW allows active tuning of transmittance through varying applied potential and function as a photovoltaic cell based on DSSC. The resulting device demonstrates fast switching rate of 1 second in both bleaching and coloring process through the use of electrochromic polymer as a counter electrode layer. In order to increase the transmittance of the device, cobalt redox couple and light colored yet efficient organic dye are employed. The organic dye utilized contains polymeric structure, which contributes to high cyclic stability. The device exhibits power conversion efficiency (PCE) of 4.5 % under AM 1.5 irradiation (100 mW/cm2), change in transmittance (Delta T = Tmax - Tmin) of 34 % upon applied potential, and shows only 3 % degradation in PCE after 5000 cycles.

Inertial Confinement Fusion and the National Ignition Facility (NIF)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ross, P.

2012-08-29

Inertial confinement fusion (ICF) seeks to provide sustainable fusion energy by compressing frozen deuterium and tritium fuel to extremely high densities. The advantages of fusion vs. fission are discussed, including total energy per reaction and energy per nucleon. The Lawson Criterion, defining the requirements for ignition, is derived and explained. Different confinement methods and their implications are discussed. The feasibility of creating a power plant using ICF is analyzed using realistic and feasible numbers. The National Ignition Facility (NIF) at Lawrence Livermore National Laboratory is shown as a significant step forward toward making a fusion power plant based on ICF.more » NIF is the world’s largest laser, delivering 1.8 MJ of energy, with a peak power greater than 500 TW. NIF is actively striving toward the goal of fusion energy. Other uses for NIF are discussed.« less

Investigation on efficiency declines due to spectral overlap between LDAs pump and laser medium in high power double face pumped slab laser

NASA Astrophysics Data System (ADS)

Lang, Ye; Chen, Yanzhong; Liao, Lifen; Guo, Guangyan; He, Jianguo; Fan, Zhongwei

2018-03-01

In high power diode lasers, the input cooling water temperature would affect both output power and output spectrum. In double face pumped slab laser, the spectrum of two laser diode arrays (LDAs) must be optimized for efficiency reason. The spectrum mismatch of two LDAs would result in energy storing decline. In this work, thermal induced efficiency decline due to spectral overlap between high power LDAs and laser medium was investigated. A numerical model was developed to describe the energy storing variation with changing LDAs cooling water temperature and configuration (series/parallel connected). A confirmatory experiment was conducted using a double face pumped slab module. The experiment results show good agreements with simulations.

Cryogenic ultra-high power infrared diode laser bars

NASA Astrophysics Data System (ADS)

Crump, Paul; Frevert, C.; Hösler, H.; Bugge, F.; Knigge, S.; Pittroff, W.; Erbert, G.; Tränkle, G.

2014-02-01

GaAs-based high power diode lasers are the most efficient source of optical energy, and are in wide use in industrial applications, either directly or as pump sources for other laser media. Increased output power per laser is required to enable new applications (increased optical power density) and to reduce cost (more output per component leads to lower cost in $/W). For example, laser bars in the 9xx nm wavelength range with the very highest power and efficiency are needed as pump sources for many high-energy-class solid-state laser systems. We here present latest performance progress using a novel design approach that leverages operation at temperatures below 0°C for increases in bar power and efficiency. We show experimentally that operation at -55°C increases conversion efficiency and suppresses thermal rollover, enabling peak quasi-continuous wave bar powers of Pout > 1.6 kW to be achieved (1.2 ms, 10 Hz), limited by the available current. The conversion efficiency at 1.6 kW is 53%. Following on from this demonstration work, the key open challenge is to develop designs that deliver higher efficiencies, targeting > 80% at 1.6 kW. We present an analysis of the limiting factors and show that low electrical resistance is crucial, meaning that long resonators and high fill factor are needed. We review also progress in epitaxial design developments that leverage low temperatures to enable both low resistance and high optical performance. Latest results will be presented, summarizing the impact on bar performance and options for further improvements to efficiency will also be reviewed.

Lightweight High Efficiency Electric Motors for Space Applications

NASA Technical Reports Server (NTRS)

Robertson, Glen A.; Tyler, Tony R.; Piper, P. J.

2011-01-01

Lightweight high efficiency electric motors are needed across a wide range of space applications from - thrust vector actuator control for launch and flight applications to - general vehicle, base camp habitat and experiment control for various mechanisms to - robotics for various stationary and mobile space exploration missions. QM Power?s Parallel Path Magnetic Technology Motors have slowly proven themselves to be a leading motor technology in this area; winning a NASA Phase II for "Lightweight High Efficiency Electric Motors and Actuators for Low Temperature Mobility and Robotics Applications" a US Army Phase II SBIR for "Improved Robot Actuator Motors for Medical Applications", an NSF Phase II SBIR for "Novel Low-Cost Electric Motors for Variable Speed Applications" and a DOE SBIR Phase I for "High Efficiency Commercial Refrigeration Motors" Parallel Path Magnetic Technology obtains the benefits of using permanent magnets while minimizing the historical trade-offs/limitations found in conventional permanent magnet designs. The resulting devices are smaller, lower weight, lower cost and have higher efficiency than competitive permanent magnet and non-permanent magnet designs. QM Power?s motors have been extensively tested and successfully validated by multiple commercial and aerospace customers and partners as Boeing Research and Technology. Prototypes have been made between 0.1 and 10 HP. They are also in the process of scaling motors to over 100kW with their development partners. In this paper, Parallel Path Magnetic Technology Motors will be discussed; specifically addressing their higher efficiency, higher power density, lighter weight, smaller physical size, higher low end torque, wider power zone, cooler temperatures, and greater reliability with lower cost and significant environment benefit for the same peak output power compared to typically motors. A further discussion on the inherent redundancy of these motors for space applications will be provided.

High efficiency solar panel /HESP/

NASA Technical Reports Server (NTRS)

Stella, P. M.; Gay, C.; Uno, F.; Scott-Monck, J.

1978-01-01

A family of high efficiency, weldable silicon solar cells, incorporating nearly every feature of advanced cell technology developed in the past four years, was produced and subjected to space qualification testing. This matrix contained both field and non-field cells ranging in thickness from 0.10 mm to 0.30 mm, and in base resistivity from nominal two to one hundred ohm-cm. Initial power outputs as high as 20 mW/sq cm (14.8% AM0 efficiency) were produced by certain cell types within the matrix.

Possible application of electromagnetic guns to impact fusion

NASA Astrophysics Data System (ADS)

Kostoff, R. N.; Peaslee, A. T., Jr.; Ribe, F. L.

1982-01-01

The possible application of electromagnetic guns to impact fusion for the generation of electric power is discussed, and advantages of impact fusion over the more conventional inertial confinement fusion concepts are examined. It is shown that impact fusion can achieve the necessary high yields, of the order of a few gigajoules, which are difficult to achieve with lasers except at unrealistically high target gains. The rail gun accelerator is well adapted to the delivery of some 10-100 megajoules of energy to the fusion target, and the electrical technology involved is relatively simple: inductive storage or rotating machinery and capacitors. It is concluded that the rail gun has the potential of developing into an impact fusion macroparticle accelerator.

Telescoping Solar Array Concept for Achieving High Packaging Efficiency

NASA Technical Reports Server (NTRS)

Mikulas, Martin; Pappa, Richard; Warren, Jay; Rose, Geoff

2015-01-01

Lightweight, high-efficiency solar arrays are required for future deep space missions using high-power Solar Electric Propulsion (SEP). Structural performance metrics for state-of-the art 30-50 kW flexible blanket arrays recently demonstrated in ground tests are approximately 40 kW/cu m packaging efficiency, 150 W/kg specific power, 0.1 Hz deployed stiffness, and 0.2 g deployed strength. Much larger arrays with up to a megawatt or more of power and improved packaging and specific power are of interest to mission planners for minimizing launch and life cycle costs of Mars exploration. A new concept referred to as the Compact Telescoping Array (CTA) with 60 kW/cu m packaging efficiency at 1 MW of power is described herein. Performance metrics as a function of array size and corresponding power level are derived analytically and validated by finite element analysis. Feasible CTA packaging and deployment approaches are also described. The CTA was developed, in part, to serve as a NASA reference solar array concept against which other proposed designs of 50-1000 kW arrays for future high-power SEP missions could be compared.

Z-Pinch Fusion Propulsion

NASA Technical Reports Server (NTRS)

Miernik, Janie

2011-01-01

Fusion-based nuclear propulsion has the potential to enable fast interplanetary transportation. Shorter trips are better for humans in the harmful radiation environment of deep space. Nuclear propulsion and power plants can enable high Ispand payload mass fractions because they require less fuel mass. Fusion energy research has characterized the Z-Pinch dense plasma focus method. (1) Lightning is form of pinched plasma electrical discharge phenomena. (2) Wire array Z-Pinch experiments are commonly studied and nuclear power plant configurations have been proposed. (3) Used in the field of Nuclear Weapons Effects (NWE) testing in the defense industry, nuclear weapon x-rays are simulated through Z-Pinch phenomena.

High-Efficiency Synthesis of Human α-Endorphin and Magainin in the Erythrocytes of Transgenic Mice: A Production System for Therapeutic Peptides

NASA Astrophysics Data System (ADS)

Sharma, Ajay; Khoury-Christianson, Anastasia M.; White, Steven P.; Dhanjal, Nirpal K.; Huang, Wen; Paulhiac, Clara; Friedman, Eric J.; Manjula, Belur N.; Kumar, Ramesh

1994-09-01

Chemical synthesis of peptides, though feasible, is hindered by considerations of cost, purity, and efficiency of synthesizing longer chains. Here we describe a transgenic system for producing peptides of therapeutic interest as fusion proteins at low cost and high purity. Transgenic hemoglobin expression technology using the locus control region was employed to produce fusion hemoglobins in the erythrocytes of mice. The fusion hemoglobin contains the desired peptide as an extension at the C end of human α-globin. A protein cleavage site is inserted between the C end of the α-globin chain and the N-terminal residue of the desired peptide. The peptide is recovered after cleavage of the fusion protein with enzymes that recognize this cleavage signal as their substrate. Due to the selective compartmentalization of hemoglobin in the erythrocytes, purification of the fusion hemoglobin is easy and efficient. Because of its compact and highly ordered structure, the internal sites of hemoglobin are resistant to protease digestion and the desired peptide is efficiently released and recovered. The applicability of this approach was established by producing a 16-mer α-endorphin peptide and a 26-mer magainin peptide in transgenic mice. Transgenic animals and their progeny expressing these fusion proteins remain healthy, even when the fusion protein is expressed at >25% of the total hemoglobin in the erythrocytes. Additional applications and potential improvements of this methodology are discussed.

High-power 671  nm laser by second-harmonic generation with 93% efficiency in an external ring cavity.

PubMed

Cui, Xing-Yang; Shen, Qi; Yan, Mei-Chen; Zeng, Chao; Yuan, Tao; Zhang, Wen-Zhuo; Yao, Xing-Can; Peng, Cheng-Zhi; Jiang, Xiao; Chen, Yu-Ao; Pan, Jian-Wei

2018-04-15

Second-harmonic generation (SHG) is useful for obtaining single-frequency continuous-wave laser sources at various wavelengths for applications ranging from biology to fundamental physics. Using an external power-enhancement cavity is an effective approach to improve the frequency conversion efficiency. However, thermal effects limit the efficiency, particularly, in high-power operation. Therefore, reducing thermal effects is important when designing a cavity. This Letter reports the use of an external ring cavity for SHG, yielding a 5.2 W, 671 nm laser light with a conversion efficiency of 93.8±0.8% which, to the best of our knowledge, is a new record of conversion efficiency for an external ring cavity. It is achieved using a 10 mm length periodically poled potassium titanyl phosphate crystal and a 65 μm radius beam waist in the cavity so as to minimize thermal dephasing and thermal lensing. Furthermore, a method is developed to determine a conversion efficiency more accurately based on measuring the pump depletion using a photodiode detector and a maximum pump depletion up to 97% is recorded. In this method, the uncertainty is much less than that achieved in a common method by direct measuring with a power meter.

Efficient, high power, Q-switched Nd:YLF slab laser end-pumped by diode stack

NASA Astrophysics Data System (ADS)

Zhang, Hengli; Li, Daijun; Shi, Peng; Diart, Rober; Shell, Alexander; Haas, Claus R.; Du, Keming

2005-06-01

A high power diode stack end-pumped electro-optically Q-switched Nd:YLF slab laser with a stable and off-axis negative-branch confocal unstable hybrid resonator was demonstrated. By using a cylindrical lens in the stable direction the thermal lens effect was compensated. Pulse energy of 25 mJ was obtained with a pulse width of 22.4 ns at repetition rates of 500 Hz and a conversion efficiency of 22%. The stability was better than 0.8% and the beam propagation M2 factor was about 1.2.

On Heat Loading, Novel Divertors, and Fusion Reactors

NASA Astrophysics Data System (ADS)

Kotschenreuther, Mike

2006-10-01

A new magnetic divertor geometry has been proposed to solve reactor heat exhaust problems, which are far more severe for a reactor than for ITER. Using reactor-compatible coils to generate an extra X-point downstream from the main X-point, the new X-divertor (XD) is shown to greatly expand magnetic flux at the divertor plates. As a result, the heat is distributed over a larger area and the line length is greatly increased. The heat-flux limitations of a standard divertor (SD) force a high core radiation fraction (fRad) in most reactor designs that necessarily have a several times higher ratio of heating power to radius (P/R) than ITER. It is argued that such high values of fRad will probably have serious deleterious consequences on the core confinement and stability of a burning plasma. Operation with internal transport barriers (ITBs) does not appear to overcome this problem. By reducing the core fRad within an acceptable range, the X-divertor is shown to substantially lower the core confinement requirement for a fusion reactor. As a bonus, the XD also enables the use of liquid metals by reducing the MHD drag. A possible series of experiments for an efficient and attractive path to practical fusion power is suggested.

CRISPRscan: designing highly efficient sgRNAs for CRISPR/Cas9 targeting in vivo

PubMed Central

Moreno-Mateos, Miguel A.; Vejnar, Charles E.; Beaudoin, Jean-Denis; Fernandez, Juan P.; Mis, Emily K.; Khokha, Mustafa K.; Giraldez, Antonio J.

2015-01-01

CRISPR/Cas9 technology provides a powerful system for genome engineering. However, variable activity across different single guide RNAs (sgRNAs) remains a significant limitation. We have analyzed the molecular features that influence sgRNA stability, activity and loading into Cas9 in vivo. We observe that guanine enrichment and adenine depletion increase sgRNA stability and activity, while loading, nucleosome positioning and Cas9 off-target binding are not major determinants. We additionally identified truncated and 5′ mismatch-containing sgRNAs as efficient alternatives to canonical sgRNAs. Based on these results, we created a predictive sgRNA-scoring algorithm (CRISPRscan.org) that effectively captures the sequence features affecting Cas9/sgRNA activity in vivo. Finally, we show that targeting Cas9 to the germ line using a Cas9-nanos-3′-UTR fusion can generate maternal-zygotic mutants, increase viability and reduce somatic mutations. Together, these results provide novel insights into the determinants that influence Cas9 activity and a framework to identify highly efficient sgRNAs for genome targeting in vivo. PMID:26322839

Impact of physics and technology innovations on compact tokamak fusion pilot plants

NASA Astrophysics Data System (ADS)

Menard, Jonathan

2016-10-01

For magnetic fusion to be economically attractive and have near-term impact on the world energy scene it is important to focus on key physics and technology innovations that could enable net electricity production at reduced size and cost. The tokamak is presently closest to achieving the fusion conditions necessary for net electricity at acceptable device size, although sustaining high-performance scenarios free of disruptions remains a significant challenge for the tokamak approach. Previous pilot plant studies have shown that electricity gain is proportional to the product of the fusion gain, blanket thermal conversion efficiency, and auxiliary heating wall-plug efficiency. In this work, the impact of several innovations is assessed with respect to maximizing fusion gain. At fixed bootstrap current fraction, fusion gain varies approximately as the square of the confinement multiplier, normalized beta, and major radius, and varies as the toroidal field and elongation both to the third power. For example, REBCO high-temperature superconductors (HTS) offer the potential to operate at much higher toroidal field than present fusion magnets, but HTS cables are also beginning to access winding pack current densities up to an order of magnitude higher than present technology, and smaller HTS TF magnet sizes make low-aspect-ratio HTS tokamaks potentially attractive by leveraging naturally higher normalized beta and elongation. Further, advances in kinetic stabilization and feedback control of resistive wall modes could also enable significant increases in normalized beta and fusion gain. Significant reductions in pilot plant size will also likely require increased plasma energy confinement, and control of turbulence and/or low edge recycling (for example using lithium walls) would have major impact on fusion gain. Reduced device size could also exacerbate divertor heat loads, and the impact of novel divertor solutions on pilot plant configurations is addressed. For

The connotation interpretation of high-efficiency agriculture under the perspective of a combined agriculture with tourism

NASA Astrophysics Data System (ADS)

Zhou, Jie; Zhang, Feng-tai; Gai, Yuan-jin; Deng, Bao-kun; Shao, Ji-xin; An, You-zhi

2017-08-01

Through literature review, the article points out that the existing of the high-efficiency agriculture definition is limited to results oriented thinking, apparently lack of process oriented thinking. Combined with the connotation of fusion agriculture and tourism, respectively from the time and space utilization efficiency, cash cost, elements of input and output form, etc, gives high-efficiency agriculture a new connotation. Under the perspective of a combined agriculture with tourism, efficient use of time and space, low realized cost, less costs and output form of agriculture, this is highly effective agriculture.

Advanced Power Conversion Efficiency in Inventive Plasma for Hybrid Toroidal Reactor

NASA Astrophysics Data System (ADS)

Hançerlioğullari, Aybaba; Cini, Mesut; Güdal, Murat

2013-08-01

Apex hybrid reactor has a good potential to utilize uranium and thorium fuels in the future. This toroidal reactor is a type of system that facilitates the occurrence of the nuclear fusion and fission events together. The most important feature of hybrid reactor is that the first wall surrounding the plasma is liquid. The advantages of utilizing a liquid wall are high power density capacity good power transformation productivity, the magnitude of the reactor's operational duration, low failure percentage, short maintenance time and the inclusion of the system's simple technology and material. The analysis has been made using the MCNP Monte Carlo code and ENDF/B-V-VI nuclear data. Around the fusion chamber, molten salts Flibe (LI2BeF4), lead-lithium (PbLi), Li-Sn, thin-lityum (Li20Sn80) have used as cooling materials. APEX reactor has modeled in the torus form by adding nuclear materials of low significance in the specified percentages between 0 and 12 % to the molten salts. In this study, the neutronic performance of the APEX fusion reactor using various molten salts has been investigated. The nuclear parameters of Apex reactor has been searched for Flibe (LI2BeF4) and Li-Sn, for blanket layers. In case of usage of the Flibe (LI2BeF4), PbLi, and thin-lityum (Li20Sn80) salt solutions at APEX toroidal reactors, fissile material production per source neutron, tritium production speed, total fission rate, energy reproduction factor has been calculated, the results obtained for both salt solutions are compared.

Thermal investigation on high power dfb broad area lasers at 975 nm, with 60% efficiency

NASA Astrophysics Data System (ADS)

Mostallino, R.; Garcia, M.; Deshayes, Y.; Larrue, A.; Robert, Y.; Vinet, E.; Bechou, L.; Lecomte, M.; Parillaud, O.; Krakowski, M.

2016-03-01

The demand of high power diode lasers in the range of 910-980nm is regularly growing. This kind of device for many applications, such as fiber laser pumping [1], material processing [1], solid-state laser pumping [1], defense and medical/dental. The key role of this device lies in the efficiency (𝜂𝐸) of converting input electrical power into output optical power. The high value of 𝜂𝐸 allows high power level and reduces the need in heat dissipation. The requirement of wavelength stabilization with temperature is more obvious in the case of multimode 975nm diode lasers used for pumping Yb, Er and Yb/Er co-doped solid-state lasers, due to the narrow absorption line close to this wavelength. Such spectral width property (<1 nm), combined with wavelength thermal stabilization (0.07 𝑛𝑚 • °𝐶-1), provided by a uniform distributed feedback grating (DFB) introduced by etching and re-growth process techniques, is achievable in high power diode lasers using optical feedback. This paper reports on the development of the diode laser structure and the process techniques required to write the gratings taking into account of the thermal dissipation and optical performances. Performances are particularly determined in terms of experimental electro-optical characterizations. One of the main objectives is to determine the thermal resistance of the complete assembly to ensure the mastering of the diode laser temperature for operating condition. The classical approach to determine junction temperature is based on the infrared thermal camera, the spectral measurement and the pulse electrical method. In our case, we base our measurement on the spectral measurement but this approach is not well adapted to the high power diodes laser studied. We develop a new measurement based on the pulse electrical method and using the T3STERequipment. This method is well known for electronic devices and LEDs but is weakly developed for the high

The defects and microstructure in the fusion zone of multipass laser welded joints with Inconel 52M filler wire for nuclear power plants

NASA Astrophysics Data System (ADS)

Li, Gang; Lu, Xiaofeng; Zhu, Xiaolei; Huang, Jian; Liu, Luwei; Wu, Yixiong

2017-09-01

The defects and microstructure in the fusion zone of multipass laser welded joints with Inconel 52M filler wire are investigated for nuclear power plants. Experimental results indicate that the incomplete fusion forms as the deposited metals do not completely cover the groove during multipass laser welding. The dendritic morphologies are observed on the inner surface of the porosity in the fusion zone. Many small cellular are found in the zones near the fusion boundary. With solidification preceding, cellular gradually turn into columnar dendrites and symmetrical columnar dendrites are exhibited in the weld center of the fusion zone. The fine equiaxed grains form and columnar dendrites disappear in the remelted zone of two passes. The dendrite arm spacing in the fusion zone becomes widened with increasing welding heat input. Nb-rich carbides/carbonitrides are preferentially precipitated in the fusion zone of multipass laser welded joints. In respect to high cooling rate during multipass laser welding, element segregation could be insufficient to achieve the component of Laves phase.

High to ultra-high power electrical energy storage.

PubMed

Sherrill, Stefanie A; Banerjee, Parag; Rubloff, Gary W; Lee, Sang Bok

2011-12-14

High power electrical energy storage systems are becoming critical devices for advanced energy storage technology. This is true in part due to their high rate capabilities and moderate energy densities which allow them to capture power efficiently from evanescent, renewable energy sources. High power systems include both electrochemical capacitors and electrostatic capacitors. These devices have fast charging and discharging rates, supplying energy within seconds or less. Recent research has focused on increasing power and energy density of the devices using advanced materials and novel architectural design. An increase in understanding of structure-property relationships in nanomaterials and interfaces and the ability to control nanostructures precisely has led to an immense improvement in the performance characteristics of these devices. In this review, we discuss the recent advances for both electrochemical and electrostatic capacitors as high power electrical energy storage systems, and propose directions and challenges for the future. We asses the opportunities in nanostructure-based high power electrical energy storage devices and include electrochemical and electrostatic capacitors for their potential to open the door to a new regime of power energy.

Parametric Instabilities During High Power Helicon Wave Injection on DIII-D

NASA Astrophysics Data System (ADS)

Porkolab, M.; Pinsker, R. I.

2017-10-01

High power helicon (whistler) waves at a frequency of 0.47 GHz are being considered for efficient off-axis current generation in high performance DIII-D plasmas and in K-Star [3]. The need for deploying helicon waves for current profile control has been noted in previous publications since penetration to the core of reactor grade plasmas is easier than with lower hybrid slow waves (LHCD) which suffer from accessibility limitations and strong electron Landau absorption in fusion grade high temperature plasmas. In this work we show that under typical experimental conditions in present day tokamaks with 1 MW of RF power coupled per antenna, the associated perpendicular electric fields of the order of 40 kV/m can drive strong parametric decay instabilities near the lower hybrid layer. The EXB and polarization drift velocities which are the dominant driver of the PDI can be comparable to the speed of sound in the outer plasma layers, a key measure of driving PDI instabilities. Here we calculate growth rates and convective thresholds for PDIs, and we find that decay waves into hot ion lower hybrid waves and ion cyclotron quasi modes dominate in the vicinity of the lower hybrid layer, possibly leading to pump depletion. Such instabilities in future reactor grade high temperature plasmas are less likely.

Recycled Thermal Energy from High Power Light Emitting Diode Light Source.

PubMed

Ji, Jae-Hoon; Jo, GaeHun; Ha, Jae-Geun; Koo, Sang-Mo; Kamiko, Masao; Hong, JunHee; Koh, Jung-Hyuk

2018-09-01

In this research, the recycled electrical energy from wasted thermal energy in high power Light Emitting Diode (LED) system will be investigated. The luminous efficiency of lights has been improved in recent years by employing the high power LED system, therefore energy efficiency was improved compared with that of typical lighting sources. To increase energy efficiency of high power LED system further, wasted thermal energy should be re-considered. Therefore, wasted thermal energy was collected and re-used them as electrical energy. The increased electrical efficiency of high power LED devices was accomplished by considering the recycled heat energy, which is wasted thermal energy from the LED. In this work, increased electrical efficiency will be considered and investigated by employing the high power LED system, which has high thermal loss during the operating time. For this research, well designed thermoelement with heat radiation system was employed to enhance the collecting thermal energy from the LED system, and then convert it as recycled electrical energy.

Control of mechanically activated polymersome fusion: Factors affecting fusion

DOE PAGES

Henderson, Ian M.; Paxton, Walter F.

2014-12-15

Previously we have studied the mechanically-activated fusion of extruded (200 nm) polymer vesicles into giant polymersomes using agitation in the presence of salt. In this study we have investigated several factors contributing to this phenomenon, including the effects of (i) polymer vesicle concentration, (ii) agitation speed and duration, and iii) variation of the salt and its concentration. It was found that increasing the concentration of the polymer dramatically increases the production of giant vesicles through the increased collisions of polymersomes. Our investigations also found that increasing the frequency of agitation increased the efficiency of fusion, though ultimately limited the sizemore » of vesicle which could be produced due to the high shear involved. Finally it was determined that salt-mediation of the fusion process was not limited to NaCl, but is instead a general effect facilitated by the presence of solvated ionic compounds, albeit with different salts initiating fusion at different concentration.« less

Pulsed Power Design for a Small Repetitively Pulsed Electron Beam Pumped KrF Laser

DTIC Science & Technology

2003-06-01

fusion energy (IFE) requirements for rep-rate, efficiency, durability and cost. We have designed a pulsed power system for the pre-amplifier in the Electra...new advanced pulsed power topology that can meet the fusion energy requirements for durability, repetition rate, and cost. The pulsed power will first

Exploring lower-cost pathways to economical fusion power

DOE PAGES

Hsu, Scott C.

2017-08-04

This project, the Plasma Liner Experiment–ALPHA (PLX-α)5,is one of nine projects supported by the ALPHA Program6 of the Advanced Research Projects Agency–Energy (ARPA-E) of the U.S. Department of Energy (DOE). We use innovative, low-cost coaxial plasma guns (Fig. 1), developed and built by partner HyperV Technologies Corp.7, to launch a spherically converging array of supersonic plasma jets toward the middle of a large, spherical vacuum chamber (Fig. 2). A key near-term goal of PLX-α is to merge up to 60 plasma jets to form a spherically imploding plasma liner, as a low-cost, high-shot-rate driver for compressing magnetised target plasmas tomore » fusion conditions. Our approach is known as plasma-jet-driven MIF (or PJMIF)8. A new startup company HyperJet Fusion Corporation (which recently received seed funding from Strong Atomics, LLC, a new fusion venture fund) aims to develop PJMIF under continued public and private sponsorship.« less

Exploring lower-cost pathways to economical fusion power

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hsu, Scott C.

This project, the Plasma Liner Experiment–ALPHA (PLX-α)5,is one of nine projects supported by the ALPHA Program6 of the Advanced Research Projects Agency–Energy (ARPA-E) of the U.S. Department of Energy (DOE). We use innovative, low-cost coaxial plasma guns (Fig. 1), developed and built by partner HyperV Technologies Corp.7, to launch a spherically converging array of supersonic plasma jets toward the middle of a large, spherical vacuum chamber (Fig. 2). A key near-term goal of PLX-α is to merge up to 60 plasma jets to form a spherically imploding plasma liner, as a low-cost, high-shot-rate driver for compressing magnetised target plasmas tomore » fusion conditions. Our approach is known as plasma-jet-driven MIF (or PJMIF)8. A new startup company HyperJet Fusion Corporation (which recently received seed funding from Strong Atomics, LLC, a new fusion venture fund) aims to develop PJMIF under continued public and private sponsorship.« less

Investigating power capping toward energy-efficient scientific applications: Investigating Power Capping toward Energy-Efficient Scientific Applications

DOE PAGES

Haidar, Azzam; Jagode, Heike; Vaccaro, Phil; ...

2018-03-22

The emergence of power efficiency as a primary constraint in processor and system design poses new challenges concerning power and energy awareness for numerical libraries and scientific applications. Power consumption also plays a major role in the design of data centers, which may house petascale or exascale-level computing systems. At these extreme scales, understanding and improving the energy efficiency of numerical libraries and their related applications becomes a crucial part of the successful implementation and operation of the computing system. In this paper, we study and investigate the practice of controlling a compute system's power usage, and we explore howmore » different power caps affect the performance of numerical algorithms with different computational intensities. Further, we determine the impact, in terms of performance and energy usage, that these caps have on a system running scientific applications. This analysis will enable us to characterize the types of algorithms that benefit most from these power management schemes. Our experiments are performed using a set of representative kernels and several popular scientific benchmarks. Lastly, we quantify a number of power and performance measurements and draw observations and conclusions that can be viewed as a roadmap to achieving energy efficiency in the design and execution of scientific algorithms.« less

Investigating power capping toward energy-efficient scientific applications: Investigating Power Capping toward Energy-Efficient Scientific Applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Haidar, Azzam; Jagode, Heike; Vaccaro, Phil

The emergence of power efficiency as a primary constraint in processor and system design poses new challenges concerning power and energy awareness for numerical libraries and scientific applications. Power consumption also plays a major role in the design of data centers, which may house petascale or exascale-level computing systems. At these extreme scales, understanding and improving the energy efficiency of numerical libraries and their related applications becomes a crucial part of the successful implementation and operation of the computing system. In this paper, we study and investigate the practice of controlling a compute system's power usage, and we explore howmore » different power caps affect the performance of numerical algorithms with different computational intensities. Further, we determine the impact, in terms of performance and energy usage, that these caps have on a system running scientific applications. This analysis will enable us to characterize the types of algorithms that benefit most from these power management schemes. Our experiments are performed using a set of representative kernels and several popular scientific benchmarks. Lastly, we quantify a number of power and performance measurements and draw observations and conclusions that can be viewed as a roadmap to achieving energy efficiency in the design and execution of scientific algorithms.« less

Highly efficient white OLEDs for lighting applications

NASA Astrophysics Data System (ADS)

Murano, Sven; Burghart, Markus; Birnstock, Jan; Wellmann, Philipp; Vehse, Martin; Werner, Ansgar; Canzler, Tobias; Stübinger, Thomas; He, Gufeng; Pfeiffer, Martin; Boerner, Herbert

2005-10-01

The use of organic light-emitting diodes (OLEDs) for large area general lighting purposes is gaining increasing interest during the recent years. Especially small molecule based OLEDs have already shown their potential for future applications. For white light emission OLEDs, power efficiencies exceeding that of incandescent bulbs could already be demonstrated, however additional improvements are needed to further mature the technology allowing for commercial applications as general purpose illuminating sources. Ultimately the efficiencies of fluorescent tubes should be reached or even excelled, a goal which could already be achieved in the past for green OLEDs.1 In this publication the authors will present highly efficient white OLEDs based on an intentional doping of the charge carrier transport layers and the usage of different state of the art emission principles. This presentation will compare white PIN-OLEDs based on phosphorescent emitters, fluorescent emitters and stacked OLEDs. It will be demonstrated that the reduction of the operating voltage by the use of intentionally doped transport layers leads to very high power efficiencies for white OLEDs, demonstrating power efficiencies of well above 20 lm/W @ 1000 cd/m2. The color rendering properties of the emitted light is very high and CRIs between 85 and 95 are achieved, therefore the requirements for standard applications in the field of lighting applications could be clearly fulfilled. The color coordinates of the light emission can be tuned within a wide range through the implementation of minor structural changes.

LED power efficiency of biomass, fatty acid, and carotenoid production in Nannochloropsis microalgae.

PubMed

Ma, Ruijuan; Thomas-Hall, Skye R; Chua, Elvis T; Eltanahy, Eladl; Netzel, Michael E; Netzel, Gabriele; Lu, Yinghua; Schenk, Peer M

2018-03-01

The microalga Nannochloropsis produces high-value omega-3-rich fatty acids and carotenoids. In this study the effects of light intensity and wavelength on biomass, fatty acid, and carotenoid production with respect to light output efficiency were investigated. Similar biomass and fatty acid yields were obtained at high light intensity (150 μmol m -2  s -1 ) LEDs on day 7 and low light intensity (50 μmol m -2  s -1 ) LEDs on day 11 during cultivation, but the power efficiencies of biomass and fatty acid (specifically eicosapentaenoic acid) production were higher for low light intensity. Interestingly, low light intensity enhanced both, carotenoid power efficiency of carotenoid biosynthesis and yield. White LEDs were neither advantageous for biomass and fatty acid yields, nor the power efficiency of biomass, fatty acid, and carotenoid production. Noticeably, red LED resulted in the highest biomass and fatty acid power efficiency, suggesting that LEDs can be fine-tuned to grow Nannochloropsis algae more energy-efficiently. Copyright © 2017 Elsevier Ltd. All rights reserved.

The value of materials R&D in the fast track development of fusion power

NASA Astrophysics Data System (ADS)

Ward, D. J.; Taylor, N. P.; Cook, I.

2007-08-01

The objective of the international fusion program is the creation of power plants with attractive safety and environmental features and viable economics. There is a range of possible plants that can meet these objectives, as studied for instance in the recent EU studies of power plant concepts. All of the concepts satisfy safety and environmental objectives but the economic performance is interpreted differently in different world regions according to the perception of future energy markets. This leads to different materials performance targets and the direction and timescales of the materials development programme needed to meet those targets. In this paper, the implications for materials requirements of a fast track approach to fusion development are investigated. This includes a quantification of the overall benefits of more advanced materials: including the effect of trading off an extended development time against a reduced cost of electricity for resulting power plants.

Cosmic Evolution of Accretion Power and Fusion Power: AGN and Starbursts at High Redshifts

NASA Astrophysics Data System (ADS)

Arnold Malkan, Matthew

2009-05-01

Extragalactic astronomers have been working for decades on obtaining robust measures of the luminosities galaxies produce from stars, and from active galactic nuclei. Our ultimate goal is deriving the cosmic evolution of all radiation produced by fusion and by black hole accretion. The combined effects of dust reddening and redshift make it impossible to achieve this with optical observations alone. Fortunately, infrared thermal continuum and forbidden line emission--from warm dust grains and ionized gas, respectively--can now be measured with excellent sensitivity. However, when measuring entire galaxies, these dust and gas emissions are powered by both active galactic nuclei and starbursts, which may be hard to separate spatially. We must use the fact that the patterns of IR energy output from AGN and SBs differ, with AGN making more ionized gas and hotter dust grains. Low-resolution spectroscopy, or even narrow-band filters can sort out the line emission from both processes when they are mixed in the same galaxy. The hope is that these spectroscopic determinations of star formation rate, and mass accretion rate in relatively small samples of bright galaxies will allow a calibration of broadband continuum measures. The dust continuum emission will then be measured in enormous samples of galaxies spanning their full range of masses, metallicities, environments and redshifts. Along the way, we should learn the astrophysical basis of black hole/galaxy "co-evolution." I will summarize some of the first specific infrared steps of this ambitious agenda, taken with IRAS and ISO to 2MASS, Akari and Spitzer and other telescopes. Time permitting, some of the exciting upcoming observational prospects will be advertised.

A polymer tandem solar cell with 10.6% power conversion efficiency.

PubMed

You, Jingbi; Dou, Letian; Yoshimura, Ken; Kato, Takehito; Ohya, Kenichiro; Moriarty, Tom; Emery, Keith; Chen, Chun-Chao; Gao, Jing; Li, Gang; Yang, Yang

2013-01-01

An effective way to improve polymer solar cell efficiency is to use a tandem structure, as a broader part of the spectrum of solar radiation is used and the thermalization loss of photon energy is minimized. In the past, the lack of high-performance low-bandgap polymers was the major limiting factor for achieving high-performance tandem solar cell. Here we report the development of a high-performance low bandgap polymer (bandgap <1.4 eV), poly[2,7-(5,5-bis-(3,7-dimethyloctyl)-5H-dithieno[3,2-b:2',3'-d]pyran)-alt-4,7-(5,6-difluoro-2,1,3-benzothia diazole)] with a bandgap of 1.38 eV, high mobility, deep highest occupied molecular orbital. As a result, a single-junction device shows high external quantum efficiency of >60% and spectral response that extends to 900 nm, with a power conversion efficiency of 7.9%. The polymer enables a solution processed tandem solar cell with certified 10.6% power conversion efficiency under standard reporting conditions (25 °C, 1,000 Wm(-2), IEC 60904-3 global), which is the first certified polymer solar cell efficiency over 10%.

A new topology of fuel cell hybrid power source for efficient operation and high reliability

NASA Astrophysics Data System (ADS)

Bizon, Nicu

2011-03-01

This paper analyzes a new fuel cell Hybrid Power Source (HPS) topology having the feature to mitigate the current ripple of the fuel cell inverter system. In the operation of the inverter system that is grid connected or supplies AC motors in vehicle application, the current ripple normally appears at the DC port of the fuel cell HPS. Consequently, if mitigation measures are not applied, this ripple is back propagated to the fuel cell stack. Other features of the proposed fuel cell HPS are the Maximum Power Point (MPP) tracking, high reliability in operation under sharp power pulses and improved energy efficiency in high power applications. This topology uses an inverter system directly powered from the appropriate fuel cell stack and a controlled buck current source as low power source used for ripple mitigation. The low frequency ripple mitigation is based on active control. The anti-ripple current is injected in HPS output node and this has the LF power spectrum almost the same with the inverter ripple. Consequently, the fuel cell current ripple is mitigated by the designed active control. The ripple mitigation performances are evaluated by indicators that are defined to measure the mitigation ratio of the low frequency harmonics. In this paper it is shown that good performances are obtained by using the hysteretic current control, but better if a dedicated nonlinear controller is used. Two ways to design the nonlinear control law are proposed. First is based on simulation trials that help to draw the characteristic of ripple mitigation ratio vs. fuel cell current ripple. The second is based on Fuzzy Logic Controller (FLC). The ripple factor is up to 1% in both cases.

Review of controlled fusion research using laser heating.

NASA Technical Reports Server (NTRS)

Hertzberg, A.

1973-01-01

Development of methods for generating high laser pulse energy has stimulated research leading to new ideas for practical controlled thermonuclear fusion machines. A review is presented of some important efforts in progress, and two different approaches have been selected as examples for discussion. One involves the concept of very short pulse lasers with power output tailored, in time, to obtain a nearly isentropic compression of a deuterium-tritium pellet to very high densities and temperatures. A second approach utilizing long wavelength, long pulse, efficient gas lasers to heat a column of plasma contained in a solenoidal field is also discussed. The working requirements of the laser and various magnetic field geometries of this approach are described.

High-efficiency concentration/multi-solar-cell system for orbital power generation

NASA Technical Reports Server (NTRS)

Onffroy, J. R.; Stoltzmann, D. E.; Lin, R. J. H.; Knowles, G. R.

1980-01-01

An analysis was performed to determine the economic feasibility of a concentrating spectrophotovoltaic orbital electrical power generation system. In this system dichroic beam-splitting mirrors are used to divide the solar spectrum into several wavebands. Absorption of these wavebands by solar cells with matched energy bandgaps increases the cell efficiency while decreasing the amount of heat which must be rejected. The optical concentration is performed in two stages. The first concentration stage employs a Cassegrain-type telescope, resulting in a short system length. The output from this stage is directed to compound parabolic concentrators which comprise the second stage of concentration. Ideal efficiencies for one-, two-, three-, and four-cell systems were calculated under 1000 sun, AMO conditions, and optimum energy bands were determined. Realistic efficiencies were calculated for various combinations of Si, GaAs, Ge and GaP. Efficiencies of 32 to 33 percent were obtained with the multicell systems. The optimum system consists of an f/3.5 optical system, a beam splitter to divide the spectrum at 0.9 microns, and two solar cell arrays, GaAs and Si.

Effects of interval between fusion and activation, cytochalasin B treatment, and number of transferred embryos, on cloning efficiency in goats.

PubMed

Liu, J; Li, L L; Du, S; Bai, X Y; Zhang, H D; Tang, S; Zhao, M T; Ma, B H; Quan, F S; Zhao, X E; Zhang, Y

2011-10-01

To improve the efficiency of somatic cell nuclear transfer (SCNT) in goats, we evaluated the effects of the interval between fusion and activation (1 to 5 h), cytochalasin B (CB) treatment after electrofusion, and the number of transferred embryos on the in vivo and in vitro development of cloned caprine embryos. The majority of the reconstructed embryos had condensed chromosomes and metaphase-like chromosomes at 2 and 3 h after fusion; cleavage and blastocyst rates from those two groups were higher (P < 0.05) than those of embryos activated 1, 4, or 5 h after fusion. Treatment with CB between fusion and activation improved in vitro and in vivo development of nuclear transfer (NT) goat embryos by reducing the fragmentation rate (P < 0.05). Although there were no significant differences in NT efficiency, pregnancy rate and kids born per recipient were increased by transfer of 20 or 30 embryos per recipient compared with 10 embryos. We concluded that CB treatment for 2 to 3 h between fusion and activation was an efficient method for generating cloned goats by somatic cell NT. In addition, increasing the number of embryos transferred to each recipient resulted in more live offspring from fewer recipients. Copyright © 2011 Elsevier Inc. All rights reserved.

Compact, high power, energy efficient transmit systems for UUVs using single crystal transducers

NASA Astrophysics Data System (ADS)

Robinson, Harold

2004-05-01

UUVs are currently being designed to perform a multiplitude of tasks in ocean exploration and Naval warfighting. Many of these tasks require the use of active acoustic projectors, and many may require the UUV to operate independently for hours, days, or even weeks. In order for a UUV to be as versatile as possible, its active transmit system must be versatile as well, implying that broad acoustic bandwidths are a must. However, due to size and battery life limitations, this broadband system must also be compact and energy efficient. By virtue of their extraordinary material properties, ferroelectric single crystals are the ideal transduction material for developing such broadband systems. The effect of their high coupling factor on transmit systems shall be illustrated by showing the dramatic impact on amplifier size, power factor, and acoustic response that is possible using these materials. In particular, a transducer built with these materials can be well matched to the power amplifier, i.e., 80% or more of the amplifier power reaches the transducer, over decades of frequency. Measured results from several prototype single crystal transducers shall be presented to demonstrate that the theoretical gains are actually realizable in practical devices. [Work sponsored by DARPA.

Carnot efficiency at divergent power output

NASA Astrophysics Data System (ADS)

Polettini, Matteo; Esposito, Massimiliano

2017-05-01

The widely debated feasibility of thermodynamic machines achieving Carnot efficiency at finite power has been convincingly dismissed. Yet, the common wisdom that efficiency can only be optimal in the limit of infinitely slow processes overlooks the dual scenario of infinitely fast processes. We corroborate that efficient engines at divergent power output are not theoretically impossible, framing our claims within the theory of Stochastic Thermodynamics. We inspect the case of an electronic quantum dot coupled to three particle reservoirs to illustrate the physical rationale.

Data fusion and photometric restoration

NASA Astrophysics Data System (ADS)

Pirzkal, Norbert; Hook, Richard N.

2001-11-01

The current generation of 8-10m optical ground-based telescopes have a symbiotic relationship with space telescopes. For direct imaging in the optical the former can collect photons relatively cheaply but the latter can still achieve, even in the era of adaptive optics, significantly higher spatial resolution, point-spread function stability and astrometric fidelity over fields of a few arcminutes. The large archives of HST imaging already in place, when combined with the ease of access to ground-based data afforded by the virtual observatory currently under development, will make space-ground data fusion a powerful tool for the future. We describe a photometric image restoration method that we have developed which allows the efficient and accurate use of high-resolution space imaging of crowded fields to extract high quality photometry from very crowded ground-based images. We illustrate the method using HST and ESO VLT/FORS imaging of a globular cluster and demonstrate quantitatively the photometric measurements quality that can achieved using the data fusion approach instead of just using data from just one telescope. This method can handle most of the common difficulties encountered when attempting this problem such as determining the geometric mapping to the requisite precision, deriving the PSF and the background.

Performance evaluation of a high power DC-DC boost converter for PV applications using SiC power devices

NASA Astrophysics Data System (ADS)

Almasoudi, Fahad M.; Alatawi, Khaled S.; Matin, Mohammad

2016-09-01

The development of Wide band gap (WBG) power devices has been attracted by many commercial companies to be available in the market because of their enormous advantages over the traditional Si power devices. An example of WBG material is SiC, which offers a number of advantages over Si material. For example, SiC has the ability of blocking higher voltages, reducing switching and conduction losses and supports high switching frequency. Consequently, SiC power devices have become the affordable choice for high frequency and power application. The goal of this paper is to study the performance of 4.5 kW, 200 kHz, 600V DC-DC boost converter operating in continuous conduction mode (CCM) for PV applications. The switching behavior and turn on and turn off losses of different switching power devices such as SiC MOSFET, SiC normally ON JFET and Si MOSFET are investigated and analyzed. Moreover, a detailed comparison is provided to show the overall efficiency of the DC-DC boost converter with different switching power devices. It is found that the efficiency of SiC power switching devices are higher than the efficiency of Si-based switching devices due to low switching and conduction losses when operating at high frequencies. According to the result, the performance of SiC switching power devices dominate the conventional Si power devices in terms of low losses, high efficiency and high power density. Accordingly, SiC power switching devices are more appropriate for PV applications where a converter of smaller size with high efficiency, and cost effective is required.

Power Budget Analysis for High Altitude Airships

NASA Technical Reports Server (NTRS)

Choi, Sang H.; Elliott, James R.; King, Glen C.

2006-01-01

The High Altitude Airship (HAA) has various potential applications and mission scenarios that require onboard energy harvesting and power distribution systems. The energy source considered for the HAA s power budget is solar photon energy that allows the use of either photovoltaic (PV) cells or advanced thermoelectric (ATE) converters. Both PV cells and an ATE system utilizing high performance thermoelectric materials were briefly compared to identify the advantages of ATE for HAA applications in this study. The ATE can generate a higher quantity of harvested energy than PV cells by utilizing the cascaded efficiency of a three-staged ATE in a tandem mode configuration. Assuming that each stage of ATE material has the figure of merit of 5, the cascaded efficiency of a three-staged ATE system approaches the overall conversion efficiency greater than 60%. Based on this estimated efficiency, the configuration of a HAA and the power utility modules are defined.

Lightweight Damage Tolerant, High-Temperature Radiators for Nuclear Power and Propulsion

NASA Technical Reports Server (NTRS)

Craven, Paul D.; SanSoucie, Michael P.

2015-01-01

NASA is increasingly emphasizing exploration to bodies beyond near-Earth orbit. New propulsion systems and new spacecraft are being built for these missions. As the target bodies get further out from Earth, high energy density systems, e.g., nuclear fusion, for propulsion and power will be advantageous. The mass and size of these systems, including supporting systems such as the heat exchange system, including thermal radiators, will need to be as small as possible. Conventional heat exchange systems are a significant portion of the total thermal management mass and size. Nuclear electric propulsion (NEP) is a promising option for high-speed, in-space travel due to the high energy density of nuclear fission power sources and efficient electric thrusters. Heat from the reactor is converted to power for use in propulsion or for system power. The heat not used in the power conversion is then radiated to space as shown in figure 1. Advanced power conversion technologies will require high operating temperatures and would benefit from lightweight radiator materials. Radiator performance dictates power output for nuclear electric propulsion systems. Pitch-based carbon fiber materials have the potential to offer significant improvements in operating temperature, thermal conductivity, and mass. These properties combine to allow significant decreases in the total mass of the radiators and significant increases in the operating temperature of the fins. A Center-funded project at NASA Marshall Space Flight Center has shown that high thermal conductivity, woven carbon fiber fins with no matrix material, can be used to dissipate waste heat from NEP systems and because of high specific power (kW/kg), will require less mass and possibly less total area than standard metal and composite radiator fins for radiating the same amount of heat. This project uses an innovative approach to reduce the mass and size required for the thermal radiators to the point that in-space NEP and power

A metamaterial electromagnetic energy rectifying surface with high harvesting efficiency

NASA Astrophysics Data System (ADS)

Duan, Xin; Chen, Xing; Zhou, Lin

2016-12-01

A novel metamaterial rectifying surface (MRS) for electromagnetic energy capture and rectification with high harvesting efficiency is presented. It is fabricated on a three-layer printed circuit board, which comprises an array of periodic metamaterial particles in the shape of mirrored split rings, a metal ground, and integrated rectifiers employing Schottky diodes. Perfect impedance matching is engineered at two interfaces, i.e. one between free space and the surface, and the other between the metamaterial particles and the rectifiers, which are connected through optimally positioned vias. Therefore, the incident electromagnetic power is captured with almost no reflection by the metamaterial particles, then channeled maximally to the rectifiers, and finally converted to direct current efficiently. Moreover, the rectifiers are behind the metal ground, avoiding the disturbance of high power incident electromagnetic waves. Such a MRS working at 2.45 GHz is designed, manufactured and measured, achieving a harvesting efficiency up to 66.9% under an incident power density of 5 mW/cm2, compared with a simulated efficiency of 72.9%. This high harvesting efficiency makes the proposed MRS an effective receiving device in practical microwave power transmission applications.

ITER Fusion Energy

ScienceCinema

Holtkamp, Norbert

2018-01-09

ITER (in Latin “the way”) is designed to demonstrate the scientific and technological feasibility of fusion energy. Fusion is the process by which two light atomic nuclei combine to form a heavier over one and thus release energy. In the fusion process two isotopes of hydrogen – deuterium and tritium – fuse together to form a helium atom and a neutron. Thus fusion could provide large scale energy production without greenhouse effects; essentially limitless fuel would be available all over the world. The principal goals of ITER are to generate 500 megawatts of fusion power for periods of 300 to 500 seconds with a fusion power multiplication factor, Q, of at least 10. Q ? 10 (input power 50 MW / output power 500 MW). The ITER Organization was officially established in Cadarache, France, on 24 October 2007. The seven members engaged in the project – China, the European Union, India, Japan, Korea, Russia and the United States – represent more than half the world’s population. The costs for ITER are shared by the seven members. The cost for the construction will be approximately 5.5 billion Euros, a similar amount is foreseen for the twenty-year phase of operation and the subsequent decommissioning.

Efficient high-power narrow-linewidth all-fibred linearly polarized ytterbium laser source

NASA Astrophysics Data System (ADS)

Bertrand, Anthony; Liégeois, Flavien; Hernandez, Yves; Giannone, Domenico

2012-06-01

We report on experimental results on a high power, all-fibred, linearly polarized, mode-locked laser at 1.03 μm. The laser generates pulses of 40 ps wide at a repetition rate of 52 MHz, exhibiting 12 kW peak power. Dispersion in optical fibres is controlled to obtain both high power and narrow spectral linewidth. The average output power reached is 25 W with a spectral linewidth of 380 pm and a near diffraction limit beam (M2 < 1.2). This laser is an ideal candidate for applications like IR spectroscopy, where high peak power and narrow linewidth are required for subsequent wavelength conversion.

Low pressure and high power rf sources for negative hydrogen ions for fusion applications (ITER neutral beam injection).

PubMed

Fantz, U; Franzen, P; Kraus, W; Falter, H D; Berger, M; Christ-Koch, S; Fröschle, M; Gutser, R; Heinemann, B; Martens, C; McNeely, P; Riedl, R; Speth, E; Wünderlich, D

2008-02-01

The international fusion experiment ITER requires for the plasma heating and current drive a neutral beam injection system based on negative hydrogen ion sources at 0.3 Pa. The ion source must deliver a current of 40 A D(-) for up to 1 h with an accelerated current density of 200 Am/(2) and a ratio of coextracted electrons to ions below 1. The extraction area is 0.2 m(2) from an aperture array with an envelope of 1.5 x 0.6 m(2). A high power rf-driven negative ion source has been successfully developed at the Max-Planck Institute for Plasma Physics (IPP) at three test facilities in parallel. Current densities of 330 and 230 Am/(2) have been achieved for hydrogen and deuterium, respectively, at a pressure of 0.3 Pa and an electron/ion ratio below 1 for a small extraction area (0.007 m(2)) and short pulses (<4 s). In the long pulse experiment, equipped with an extraction area of 0.02 m(2), the pulse length has been extended to 3600 s. A large rf source, with the width and half the height of the ITER source but without extraction system, is intended to demonstrate the size scaling and plasma homogeneity of rf ion sources. The source operates routinely now. First results on plasma homogeneity obtained from optical emission spectroscopy and Langmuir probes are very promising. Based on the success of the IPP development program, the high power rf-driven negative ion source has been chosen recently for the ITER beam systems in the ITER design review process.

Evaluation of annual efficiencies of high temperature central receiver concentrated solar power plants with thermal energy storage.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ehrhart, Brian David; Gill, David Dennis

The current study has examined four cases of a central receiver concentrated solar power plant with thermal energy storage using the DELSOL and SOLERGY computer codes. The current state-of-the-art base case was compared with a theoretical high temperature case which was based on the scaling of some input parameters and the estimation of other parameters based on performance targets from the Department of Energy SunShot Initiative. This comparison was done for both current and high temperature cases in two configurations: a surround field with an external cylindrical receiver and a north field with a single cavity receiver. There is amore » fairly dramatic difference between the design point and annual average performance, especially in the solar field and receiver subsystems, and also in energy losses due to the thermal energy storage being full to capacity. Additionally, there are relatively small differences (<2%) in annual average efficiencies between the Base and High Temperature cases, despite an increase in thermal to electric conversion efficiency of over 8%. This is due the increased thermal losses at higher temperature and operational losses due to subsystem start-up and shut-down. Thermal energy storage can mitigate some of these losses by utilizing larger thermal energy storage to ensure that the electric power production system does not need to stop and re-start as often, but solar energy is inherently transient. Economic and cost considerations were not considered here, but will have a significant impact on solar thermal electric power production strategy and sizing.« less

High-efficiency L-band T/R Module: Development Results

NASA Technical Reports Server (NTRS)

Edelstein, Wendy N.; Andricos, Constantine; Wang, Feiyu; Rutled, David B.

2005-01-01

Future interferometric synthetic aperture radar (InSAR) systems require electronically scanned phased-array antennas, where the transmit/receive (T/R) module is a key component. The T/R module efficiency is a critical figure of merit and has direct implications on the power dissipation and power generation requirements of the system. Significant improvements in the efficiency of the T/R module will make SAR missions more feasible and affordable. The results of two high-efficiency T/R modules are presented, each based on different power amplifier technologies. One module uses a 30W GaAs Class-AlB power amplifier and the second module uses a 70W LD-MOS Class-ElF power amplifier, where both modules use a common low power section. Each module operates over an 80MHz bandwidth at L-band (1.2GHz) with an overall module efficiency greater than 58%. We will present the results of these two T/R modules that have been designed, built and tested.

Highly Simplified Tandem Organic Light-Emitting Devices Incorporating a Green Phosphorescence Ultrathin Emitter within a Novel Interface Exciplex for High Efficiency.

PubMed

Xu, Ting; Zhou, Jun-Gui; Huang, Chen-Chao; Zhang, Lei; Fung, Man-Keung; Murtaza, Imran; Meng, Hong; Liao, Liang-Sheng

2017-03-29

Herein we report a novel design philosophy of tandem OLEDs incorporating a doping-free green phosphorescent bis[2-(2-pyridinyl-N)phenyl-C](acetylacetonato)iridium(III) (Ir(ppy) 2 (acac)) as an ultrathin emissive layer (UEML) into a novel interface-exciplex-forming structure of 1,1-bis[(di-4-tolylamino)phenyl]cyclohexane (TAPC) and 1,3,5-tri(p-pyrid-3-yl-phenyl)benzene (TmPyPB). Particularly, relatively low working voltage and remarkable efficiency are achieved and the designed tandem OLEDs exhibit a peak current efficiency of 135.74 cd/A (EQE = 36.85%) which is two times higher than 66.2 cd/A (EQE = 17.97%) of the device with a single emitter unit. This might be one of the highest efficiencies of OLEDs applying ultrathin emitters without light extraction. Moreover, with the proposed structure, the color gamut of the displays can be effectively increased from 76% to 82% NTSC if the same red and blue emissions as those in the NTSC are applied. A novel form of harmonious fusion among interface exciplex, UEML, and tandem structure is successfully realized, which sheds light on further development of ideal OLED structure with high efficiency, simplified fabrication, low power consumption, low cost, and improved color gamut, simultaneously.

Novel Fusion Protein Approach for Efficient High-Throughput Screening of Small Molecule–Mediating Protein-Protein Interactions in Cells and Living Animals