Aerospace Science and Technology
In this paper, we propose a quaternion based spacecraft model that describes the nadir pointing spacecraft with momentum wheel under gravity gradient torque disturbance. This state space model uses only three components of the quaternion. From this nonlinear model, we derive a linearized state space model for the spacecraft system. We show that unlike all existing quaternion models, this linearized state space model is fully controllable. Therefore, all modern control system design methods can be directly applied to the attitude control system design for momentum biased nadir pointing spacecraft. Source
Uthus D.C.,NRC |
Aha D.W.,U.S. Navy
We survey research on the analysis of multiparticipant chat. Multiple research and applied communities (e.g., AI, educational, law enforcement, military) have interest in this topic. After introducing some context, we describe relevant problems and how these have been addressed using AI techniques. We also identify recent research trends and unresolved issues that could benefit from more attention. © 2013 Elsevier B.V. Source
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The first customer for a small modular reactor (SMR) in the U.S. has selected a site located about 50 miles west of Idaho Falls, ID, for construction of a 50 MW unit. Utah Associated Municipal Power Systems (UAMPS) announced this week that the firm had chosen a preferred site within the boundaries of the Idaho National Laboratory (INL). Doug Hunter, CEO of UAMPS, made the announcement at the Intermountain Energy Summit being held in Idaho Falls. The 35-acre site is located about six miles south of the Lost River Rest Stop west of the intersection of U.S. Highways 20 & 26 and due north of EBR-1 where atomic energy was first used to generate electricity in December 1951. The site is geologically stable and far enough away from other facilities at the INL that it will not impact their operation. The INL encompasses an area of 890 square miles. The entire facility will eventually include up to 12 50 MW SMRs, turbines, storage for spent nuclear fuel, administrative offices, and transportation access. A rail line from Blackfoot, ID, to the INL may be developed further to support delivery of large reactor components. Officials in Idaho Falls said in a press statement the project could create over 1,000 jobs. Earlier this year the U.S. Department of Energy issued a permit to UAMPS as part of the site selection process. The permit opened the door to the utility to evaluate the alternative locations and make a decision to eventually build on one of them. At the same conference, Mike McGough, Chief Commercial Officer for NuScale, said that the firm is “nearly ready” to submit its SMR for design certification by the Nuclear Regulatory Commission (NRC). The company has said previously that it expects the application to be delivered to the agency by late 2016. That process will take three-to-four years after which, if successful, UAMPS will apply to the NRC for a COL to build and operate the reactors. UAMPS sells electricity at the wholesale level to utilities in seven western states. It formed the partnership with NuScale in 2013. A federal judge has ordered the Department of Energy (DOE) to let the court examine documents sought by former Idaho Governor Cecil Andrus that describe shipments of spent nuclear fuel to the INL. U.S. District Court Judge Lynn Winmill said the court will review the documents to determine if they can be released for public review. Andrus, a long time arch foe of nuclear spent fuel R&D at the INL, had sought the documents under a Freedom of Information Act request. However, DOE delivered papers with most of the information blacked out. Andrus is seeking information on several proposed small shipments of spent nuclear fuel that DOE wants to send to the INL for R&D evaluation. The shipments would require a waiver of the 1995 Settlement Agreement which sets terms for progress on cleanup of nuclear waste at the INL. Andrus has argued that no waiver can be granted until DOE can make progress with its Integrated Waste Treatment Unit (IWTW) that is supposed to turn about 1 million gallons of liquid nuclear waste into dry powder which can then be shipped to a geologic repository in New Mexico. Work began on the IWTU in 2005 at an estimated cost of about $160M. Since then costs have escalated to almost $600M and the technology is getting a review by a new site contractor, who took over this year, to find a way to make it work. Andrus filed the lawsuit when he got a pile of paper from DOE with black magic marker streaks instead of the information he wanted from the agency. He claims that granting the waiver would allow DOE to use the INL as an interim storage facility for spent nuclear fuel from the nation’s commercial reactors which are storing 77,000 tons of spent fuel. In blunt language, Andrus told the Associated Press (AP) this past week that he is suspicious of the DOE’s intentions. “We have to know what’s going on,” Andrus said. “Their stonewalling and reluctance lends credence to my suspicion. That’s all I have right now — a strong suspicion backed up by a history of an agency that has run roughshod over the public for way too many years.” AP reported that the Energy Department argues that the information can’t be made public because it involves internal communications that fall under an exemption to the act. The agency also cited attorney work-product privilege, and attorney-client privilege. Winmill in his 29-page ruling said the Energy Department’s explanation for blacking out pages of documents didn’t say whether the redactions “buried information relating to substantive policy about the transport and storage of large quantities of potentially dangerous nuclear waste, disclosure of which may very well be in the public’s interest.” Idaho Attorney General Lawrence Wasden has refused to sign a waiver for shipment of the spent fuel. Earlier this year DOE diverted the first shipment from INL to the Oak Ridge National Laboratory (ORNL) and also sent the R&D money to evaluate it to that lab. A second shipment is pending. DOE says it wants an evaluation of “high-burnup” fuel by the INL which is why it scheduled the shipments. The Department of Energy (DOE) announced this week that Rita Baranwal is the new director for the Gateway for Accelerated Innovation in Nuclear (GAIN) program. Baranwal was Director of Technology Development at Westinghouse. Baranwal brings deep private sector experience to GAIN’s mission of driving advanced nuclear toward commercialization in domestic and global markets. Baranwal takes over a program that is a bright star in the government’s efforts to promote advanced nuclear technologies. Recent accomplishments include. The GAIN initiative, announced at a White House Summit in November 2015, was created to provide support for the nearly 50 advanced nuclear startups that have been established across the U.S. Joshua Freed, a Vice President of the Third Way, a Washington, DC, think tank, wrote in a blog post that GAIN is also supporting the inaugural Nuclear Innovation Bootcamp at University of California, Berkeley. He wrote that the competitive educational program is aimed at helping young innovators develop nuclear-specific entrepreneurial skills. Additionally, the bootcamp includes opportunities for nontechnical students with backgrounds in the arts, communications, policy, and international affairs to participate as well, opening the doors to groups who traditionally have not been a part of the workforce pipeline, but are now understood as having valuable expertise for the future of nuclear.
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NRC is an independent safety regulator working for the US public Its services mainly benefit customers that in electricity service areas that include nuclear power plants as suppliers Customers will benefit by cost efficient, effective safety regulations that enable continuous improvement in plant operations and performance. Customers will benefit by cost efficient, effective safety reviews for new technologies that offer the promise for even greater improvements in performance, fuel efficiency, waste reduction, security and reliable safety features or systems The NRC annual operating budget today is approximately $950 million. It is paid, not directly by customers, but by the regulated entities. The vast majority of the NRC’s budget comes from companies operating existing nuclear power plants. This results in a situation where established suppliers in a market can influence the ability of an independent regulatory agency to approve new entrants into their market. Elected officials tend to pay attention when large companies complain about the unfairness of charging them for “services” that they are not using. Only a small portion of the operating companies are currently interested in advanced nuclear reactors or SMRs, for example. The current fee system also means that the regulatory body does not believe that it should better serve nuclear energy customers by enabling increased nuclear electricity production at lower costs. That does not mean lower requirements or scrutiny; it means implementing changes that reduce redundancy, eliminate excessively long comment periods, streamline obstructionist hearing processes, and eliminate — without a costly, time-consuming, uncertain “exemption process” — rules that are specifically written for a particular technology. Fund the activities of the Nuclear Regulatory Commission with a designated tax on nuclear generated electricity. One to two mils per kilowatt hour (0.1-0.2 cents) would be sufficient. This has been shown to be an effective and logical way to collect revenues to pay for public services and infrastructure generated by using nuclear energy. It is the way that the Nuclear Waste Fund has accumulated a balance of $30 billion. It is similar to the way that highways are funded by collecting taxes on gasoline and diesel fuel and the way that the FAA and TSA are funded by fees added to airline tickets. Any excess fees collected should be allowed to accumulate — perhaps with a certain carryover limit — because NRC expenses aren’t well suited for an annual budget cycle. The customers for the service — in this case, the portion of the public served by nuclear generated electricity — are the ones who should pay the agency providing the service. It’s always been kind of a wry joke inside the nuclear industry that regulated entities are required to pay for “the services” provided by someone who comes and inspects your work, adds new requirements, questions every statement, reviews every program, and imposes fines if errors or emissions are found. This is a “half-baked” BFO concept with a lot of details to flesh out. You have to expect materials like this sometimes when you visit a blog offered to the public by an opinionated and not terribly disciplined thinker. Comments are welcome. Revisions to the original post should be expected. The post Proposal: Fund NRC by a fee on each kw-hr generated by nuclear energy appeared first on Atomic Insights.
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Home > Press > Changing the color of single photons in a diamond quantum memory Abstract: Researchers from the Institute for Quantum Computing at the University of Waterloo and the National Research Council of Canada (NRC) have, for the first time, converted the colour and bandwidth of ultrafast single photons using a room-temperature quantum memory in diamond. Shifting the colour of a photon, or changing its frequency, is necessary to optimally link components in a quantum network. For example, in optical quantum communication, the best transmission through an optical fibre is near infrared, but many of the sensors that measure them work much better for visible light, which is a higher frequency. Being able to shift the colour of the photon between the fibre and the sensor enables higher performance operation, including bigger data rates. The research, published in Nature Communications, demonstrated small frequency shifts that are useful for a communication protocol known as wavelength division multiplexing. This is used today when a sender needs to transmit large amounts of information through a transmission so the signal is broken into smaller packets of slightly different frequencies and sent through together. The information is then organized at the other end based on those frequencies. In the experiments conducted at NRC, the researchers demonstrated the conversion of both the frequency and bandwidth of single photons using a room-temperature diamond quantum memory. "Originally there was this thought that you just stop the photon, store it for a little while and get it back out. The fact that we can manipulate it at the same time is exciting," said Kent Fisher a PhD student at the Institute for Quantum Computing and with the Department of Physics and Astronomy at Waterloo. "These findings could open the door for other uses of quantum memory as well." The diamond quantum memory works by converting the photon into a particular vibration of the carbon atoms in the diamond, called a phonon. This conversion works for many different colours of light allowing for the manipulation of a broad spectrum of light. The energy structure of diamond allows for this to occur at room temperature with very low noise. Researchers used strong laser pulses to store and retrieve the photon. By controlling the colours of these laser pulses, researchers controlled the colour of the retrieved photon. "The fragility of quantum systems means that you are always working against the clock," remarked Duncan England, researcher at NRC. "The interesting step that we've shown here is that by using extremely short pulses of light, we are able to beat the clock and maintain quantum performance." The integrated platform for photon storage and spectral conversion could be used for frequency multiplexing in quantum communication, as well as build up a very large entangled state - something called a cluster state. Researchers are interested in exploiting cluster states as the resource for quantum computing driven entirely by measurements. "Canada is a power-house in quantum research and technology. This work is another example of what partners across the country can achieve when leveraging their joint expertise to build next-generation technologies," noted Ben Sussman, program leader for NRC's Quantum Photonics program. About University of Waterloo University of Waterloo is Canada's top innovation university. With more than 36,000 students we are home to the world's largest co-operative education system of its kind. Our unmatched entrepreneurial culture, combined with an intensive focus on research, powers one of the top innovation hubs in the world. For more information, please click If you have a comment, please us. Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.