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Volunteer cleanup operations collect large datasets on anthropogenic litter that are seldom analyzed. Here we assess the influence of land use in both near-stream and watershed scale source domains on anthropogenic litter concentration (standing stock, kg km−1) in riparian zones of Iowa, USA. We utilized riparian litter concentration data on four classes of anthropogenic litter (metal, recyclable, garbage, and tires) from volunteer cleanup operations. Anthropogenic litter data were tested for correlation with near-stream and watershed scale land uses (developed, road density, agricultural, and open lands). Road density (road length/area) and developed land use (% area) were significantly correlated to anthropogenic litter, but agricultural (% area) and open lands (% area) were not. Metal objects correlated to near-stream road density (r = 0.79, p = 0.02), while garbage and recyclable materials correlated to watershed scale road density (r = 0.69, p = 0.06 and r = 0.71, p = 0.05 respectively). These differences in the important spatial scales of land use may be related to differences in transport characteristics of anthropogenic litter. Larger, denser metal objects may be transported more slowly through the watershed/channelized system and thus, dependent on more proximal sources, whereas smaller, less dense garbage and recyclable material are likely transported more rapidly, resulting in concentrations that depend more on watershed scale supply. We developed a linear regression model that used near-stream road density and the total amount of observed litter to predict an average anthropogenic litter density of 188 kg km−1 and a standing stock of 946 t in all Iowa streams (>4th Strahler order). The techniques employed in this study can be applied to other professional and volunteer litter datasets to develop prevention and cleanup efforts, inform investigations of process, and assess management actions.

With the resurgence of nuclear power and increased interest in advanced nuclear reactors as an option to supply abundant energy without the associated greenhouse gas emissions of the more conventional fossil fuel energy sources, there is a need to establish internationally recognized standards for the verification and validation (V&V) of software used to calculate the thermal–hydraulic behavior of advanced reactor designs for both normal operation and hypothetical accident conditions. To address this need, ASME (American Society of Mechanical Engineers) Standards and Certification has established the V&V 30 Committee, under the jurisdiction of the V&V Standards Committee, to develop a consensus standard for verification and validation of software used for design and analysis of advanced reactor systems. The initial focus of this committee will be on the V&V of system analysis and computational fluid dynamics (CFD) software for nuclear applications. To limit the scope of the effort, the committee will further limit its focus to software to be used in the licensing of High-Temperature Gas-Cooled Reactors. Although software verification will be an important and necessary part of the standard, much of the initial effort of the committee will be focused on the validation of existing software and new models that could be used in the licensing process. In this framework, the Standard should conform to Nuclear Regulatory Commission (NRC) and other regulatory practices, procedures and methods for licensing of nuclear power plants as embodied in the United States (U.S.) Code of Federal Regulations and other pertinent documents such as Regulatory Guide 1.203, “Transient and Accident Analysis Methods” and NUREG-0800, “NRC Standard Review Plan”. In addition, the Standard should be consistent with applicable sections of ASME NQA-1-2008 “Quality Assurance Requirements for Nuclear Facility Applications (QA)”. This paper describes the general requirements for the proposed V&V 30 Standard, which includes: (a) applicable NRC and other regulatory requirements for defining the operational and accident domain of a nuclear system that must be considered if the system is to be licensed, (b) the corresponding calculation domain of the software that should encompass the nuclear operational and accident domain to be used to study the system behavior for licensing purposes, (c) the definition of the scaled experimental data set required to provide the basis for validating the software, (d) the ensemble of experimental data sets required to populate the validation matrix for the software in question, and (e) the practices and procedures to be used when applying a validation standard. Although this initial effort will focus on software for licensing of High-Temperature Gas-Cooled Reactors, it is anticipated that the practices and procedures developed for this Standard can eventually be extended to other nuclear and non-nuclear applications.

Virtual Globe software has become extremely popular both inside and outside of educational settings. This software allows users to explore the Earth in three dimensions while streaming satellite imagery, elevation, and other data from the Internet. Virtual Globes, such as Google Earth, NASA World Wind, and ESRI's ArcGIS Explorer can be effectively used in standards-based, inquiry-driven geography lessons. With some practice, mashups (using data from more than one source to create new data) can be constructed for practically any application or area of interest. Educators who have not already begun to use these tools may wish to investigate them to help their students to think spatially by investigating processes and places on the Earth's surface in a three-dimensional visualization environment.

The very high temperature reactor (VHTR) system behavior should be predicted during normal operating conditions and postulated accident conditions. The plant accident scenario and the passive safety behavior should be accurately predicted. Uncertainties in passive safety behavior could have large effects on the resulting system characteristics. Due to these performance issues in the VHTR, there is a need for development, testing and validation of design tools to demonstrate the feasibility of the design concepts and guide the improvement of the plant components. One of the identified design issues for the gas-cooled reactor is the thermal mixing of the coolant exiting the core into the outlet plenum. Incomplete thermal mixing may give rise to thermal stresses in the downstream components. To provide flow details, the analysis presented in this paper was performed by coupling a VHTR model generated in a thermal hydraulic systems code to a computational fluid dynamics (CFD) outlet plenum model. The outlet conditions obtained from the systems code VHTR model provide the inlet boundary conditions to the CFD outlet plenum model. By coupling the two codes in this manner, the important three-dimensional flow effects in the outlet plenum are well modeled while avoiding modeling the entire reactor with a computationally expensive CFD code. The values of pressure, mass flow rate and temperature across the coupled boundary showed differences of less than 5% in every location except for one channel. The coupling auxiliary program used in this analysis can be applied to many different cases requiring detailed three-dimensional modeling in a small portion of the domain.

Rural communities of sub-Saharan Africa are under increasing adaptive pressure resulting from decline in the quality of land resources. To increase food, generate income, and safeguard against risks and shocks, families are engaging in multiple livelihood strategies. This study was conducted to: 1) evaluate livelihood strategies; 2) examine the dynamic diversification process in the agrarian and non-agrarian continuum; and 3) investigate how type and availability of assets influences choice of a livelihood strategy. Results from our investigation in western Kenya suggest that as land is subjected to degradation, there is a shift in the type of assets that families can draw upon. Among the Luo, collision between deeply embedded cultural beliefs and access to land, is leading to a shift from farming to non-farming activities. They are heavily reliant on human labor to make a living hence becoming less resilient, and more vulnerable to existing and emerging risks and shocks. The overriding scenario is escalated land degradation, increased poverty levels, and a failed social support system. Asset diversification and intensification processes among the Kipsigis are closely intertwined with rapid social-cultural change and strong bonding and bridging ties. They are involved in an asset-led intensification and diversification strategies. Overall, our findings suggest that the ability to make a meaningful livelihood is dependent not only on the quality and quantity of assets that an individual household possesses, but also having capabilities to use and transform the assets as well.

The main objective of this project was to identify and characterize the conditions under which abnormal heat transfer phenomena would occur in a Very High Temperature Reactor (VHTR) with a prismatic core. High pressure/high temperature experiments have been conducted to obtain data that could be used for validation of VHTR design and safety analysis codes. The focus of these experiments was on the generation of benchmark data for design and off-design heat transfer for forced, mixed and natural circulation in a VHTR core. In particular, a flow laminarization phenomenon was intensely investigated since it could give rise to hot spots in the VHTR core.

An enduring relationship developed between the University of Uppsala, Sweden, and the University of Illinois, Chicago, as a result of the author’s two opportunities to study and lecture in Uppsala through the auspices of the Fulbright Scholarship Awards, first at the invitation of Professor Tord Skoog in 1960, and then by Professor Valdemar Skoog in 2003. Some anecdotes and observations related to these dates and the 43-year interval are presented.

PURPOSE: To determine the accuracy of glaucoma detection by frequency-doubling perimetry. METHODS: Stereoview optic nerve photographs, visual field examination, intraocular pressure measurements, medical and ocular history, and a screening and full threshold frequency-doubling perimetry examination were performed in a prospective study of consecutive subjects. Inclusion criteria included age of 45 years or older, absence of ocular disease other than glaucoma, cataract, or mild drusen, and Snellen visual acuity of 20/60 or better. A total of 125 eyes in 102 glaucoma subjects and 95 eyes of 95 normal subjects were included. Each eye was classified as “normal,” “glaucoma,” or “uncertain” by each of three ophthalmologists on the basis of all available clinical information with the exception of frequency-doubling perimetry results. Those in the glaucoma group were subclassified as having early (n = 51), moderate (n = 42), or severe (n = 32) glaucoma on the basis of automated Humphrey visual field criteria. In the glaucoma group, two eyes from a subject were allowed to be included (23 of 102 subjects) if they differed in level of damage because they were never analyzed within the same statistical analysis. RESULTS: Several diagnostic algorithms were evaluated. Algorithms based on the most depressed single point, pair of adjacent points, and cluster of three points performed nearly identically. For the screening test, if any abnormality was identified, specificity was 95%, whereas sensitivity was 39%, 86%, and 100% for early, moderate, and severe glaucoma, respectively. For the full threshold test, with at least one point depressed to the P < 0.5% level, specificity measured 91%, whereas sensitivity was 35%, 88%, and 100% for early, moderate, and severe glaucoma, respectively. The two global indices, mean deviation and pattern standard deviation, were also evaluated and were generally less accurate. CONCLUSION: Frequency-doubling perimetry, which is rapid and easily administered, is effective at detecting moderate and severe disease and appears well suited for glaucoma screening.

In this study, computational fluid dynamics solutions are obtained for a General Atomics GT-MHR reactor core under a depressurization scenario involving highly compressible flow. It is found that w...

Super-resolution enhancement algorithms are used to estimate a high-resolution video still (HRVS) from several low-resolution frames, provided that objects within the digital image sequence move with subpixel increments. A Bayesian multi_frame enhancement algorithm is presented to compute an HRVS using the spatial information present within each frame as well as the temporal information present due to object motion between frames. However, the required subpixel-resolution motion vectors must be estimated from low-resolution and noisy video frames, resulting in an inaccurate motion field which can adversely impact the quality of the enhanced image. Several subpixel motion estimation techniques are incorporated into the Bayesian multiframe enhancement algorithm to determine their efficacy in the presence of global data transformations between frames (i.e., camera pan, rotation, tilt, and zoom) and independent object motion. Visual and quantitative comparisons of the resulting high-resolution video stills computed from two video frames and the corresponding estimated motion fields show that the eight-parameter projective motion model is appropriate for global scene changes, while block matching and Horn?Schunck optical flow estimation each have their own advantages and disadvantages when used to estimate independent object motion.

Teaching rock mechanics in the undergraduate curriculum can have two important impacts: (1) it promotes systematic thinking about geologic principles, and (2) it can motivate improved learning in other quantitative courses in the geosciences. Many of the formal critical-thinking techniques, applied judiciously, along with other nontraditional classroom techniques, can be used to convey complex mathematical and physical concepts successfully to the student.

Although use of thrombolytic therapy during primary angioplasty is controversial, the development of a monoclonal antibody (c7E3 Fab) to the platelet glycoprotein IIb/IIIa receptor has been a tremendous breakthrough in the field of interventional cardiology. Use of the antibody during high-risk angioplasty or atherectomy procedures has been shown to significantly reduce the incidence of death, MI, or emergent repeat revascularization. We describe four cases in which c7E3 Fab was used as an adjunct to coronary stenting in the peri-infarct period in patients with cardiogenic shock. To our knowledge, no other reports have addressed the use of glycoprotein IIb/IIIa receptor inhibitors with coronary stent implantation. Our experience in this small population suggests that coronary stenting for myocardial infarctions may be a feasible option in selected patients to allow maximal luminal dilation and successful reperfusion. We emphasize that our results are preliminary, and we eagerly await the results of the EPILOG study which will provide more definitive data on the safety and efficacy of c7E3 Fab and coronary stenting from the perspective of a large, randomized trial. © 1996 Willey-Liss, Inc.

Gemcitabine is a new deoxycytidine analog that exhibits significant cytotoxicity against a variety of cultured murine and human tumor cells. The cytotoxic action of gemcitabine appears to be due to the inhibition of DNA synthesis by inhibition of ribonucleotide reductase and by competition with dCTP for incorporation into DNA. We have previously shown that gemcitabine, but not cytosine arabinoside (ara-C), has a broad spectrum of antitumor activity against 7 different types of murine solid tumors. The activity of gemcitabine was schedule dependent. To further characterize its activity, gemcitabine was tested against 12 human carcinoma xenografts. When given on an every 3 day x 4 schedule, the following percent inhibitions (at maximally tolerated doses [MTD]; MTD/2) in tumor growth were seen: MX-1 mammary (93%; 80%), CX-1 colon (92%; 82%), HC-1 colon (96%; 92%), GC3 colon (98%; 94%), VRC5 colon (99%; 100%), LX-1 lung (76%; 61%), CALU-6 lung (75%; 38%), NCI-H460 lung (45%; 46%), HS766T pancreatic (73%; not tested), PaCa-2 pancreatic (69%; 40%), PANC-1 pancreatic (70%; 60%), and BxPC-3 pancreatic (9%; 19%). In contrast, only the LX-1 lung carcinoma xenograft was responsive to ara-C treatment, which inhibited tumor growth by a marginal 62 percent. Thus, like its activity against murine solid tumors, gemcitabine has excellent antitumor activity against a broad spectrum of human solid tumors.

Pancreatic cancer is the fifth leading cause of death from malignant disease in the Western world. The majority of patients with carcinoma of the exocrine pancreas haveunresectable, incurable disease at the time of diagnosis. At present, no medical treatment can be considered as standard therapy in advanced or locally unresectable pancreatic carcinoma. Since no chemotherapeutic regimen has been demonstrated to offer a clear survival benefit for these patients, future clinical trials should be designed to evaluate quality of life and palliation of symptoms, such as recent observations with gemcitabine, a novel nucleoside analogue. In this review, recent developments in our understanding of the biology and pathogenesis of pancreatic carcinoma are described. Future progress in the cellular and molecular aspects of this disease may lead to potential new remedies.

Agriculture in the United States makes intensive use of large portions, of the nation's arable landscape. This landscape is dominated by large fields of annual crops with few perennial buffering communities within them. Agroforestry systems such as riparian buffers, alleycropping, windbreaks, tree/pasture systems, and forest farming provide buffering opportunities within these landscapes. Riparian buffers and alleycropping systems provide two unique opportunities toward sustainable production by reducing nonpoint source pollution while increasing ecological diversity. The major impediment to agroforestry in the United States is a lack of identity. Agroforestry as a practice is not officially recognized by federal and most state agencies and thus does not qualify for cost-share support or funding for research and establishment of demonstrations. A recent white paper, prepared by representatives from government agencies, academic institutions, and nongovernment organizations, identified eight major actions that could provide the support, for making agroforestry an acceptable alternative to nonsustainable agriculture. Ames, Iowa. Project No. 3209.

The Modular High Temperature Gas-Cooled Reactor (MHTGR) has been chosen as a reference design for the Next Generation Nuclear Plant (NGNP) project. This reactor consists of concentric stacks of graphite blocks containing embedded fuel elements. Helium will be used as the coolant and will flow through designed coolant channels interspaced axially within the graphite blocks as well as in the gaps separating the blocks (called the bypass flow). A key phenomenon that may lead to localized hot spots in the reactor is the degradation of heat transfer effects in the bypass flow due to geometry distortions. Geometry distortions are the result of the graphite blocks being irradiated with energetic neutrons as well as coefficient of thermal expansion effects due to temperature changes. Idaho State University is studying heat transfer within the bypass flow and is developing an experiment to study the deterioration of heat transfer in the bypass flow stemming from these geometry distortions. Experimental data gathered from this project will be used to benchmark numerical codes used in the design and safety analysis of the MHTGR.Baseline MHTGR operating conditions are for a system pressure of approximately 7 MPa and a helium exit temperature from the reactor of approximately 850 °C. In place of using helium at these extreme conditions, it is our desire to perform the experiments with air entering the experiment at atmospheric pressure and temperature. Additionally, it is desirable to have an open-air system as opposed to a closed helium system. In order to quantify the impacts on temperature increase as well as pressure drop, a scaling analysis will be performed to compare the respective values from both helium and air. Important non-dimensional parameters, such as Reynolds number, non-dimensional heat flux, the acceleration factor, and non-dimensional buoyancy, will be matched for the various conditions in order to provide a similitude between the helium and air. These factors cannot be matched all at once, except by using actual conditions. The range of Reynolds number will be chosen to ensure an operating regime from the purely laminar to completely turbulent. This paper presents the results of this scaling analysis.Copyright © 2012 by ASME

VLSI technology scaling in the 32-nm node and beyond has presented designers with increasing challenges to obtain performance gains, power and area reductions each successive generation. Maximum voltage limits, decreasing interconnect performance, and device changes have forced designers to rethink system and circuit design for enhanced system performance and improved user experience.

Core bypass flow has been one of key issues in the very high temperature reactor (VHTR) design for securing core thermal margins and achieving target temperatures at the core exit. The bypass flow in a prismatic VHTR core occurs through the control element holes and the radial and axial gaps between the graphite blocks for manufacturing and refueling tolerances. These gaps vary with the core life cycles because of the irradiation swelling/shrinkage characteristic of the graphite blocks such as fuel and reflector blocks, which are main components of a core's structure. Thus, the core bypass flow occurs in a complicated multidimensional way. The accurate prediction of this bypass flow and counter-measures to minimize it are thus of major importance in assuring core thermal margins and securing higher core efficiency. Even with this importance, there has not been much effort in quantifying and accurately modeling the effect of the core bypass flow. The main objectives of this project were to generate experimental data for validating the software to be used to calculate the bypass flow in a prismatic VHTR core, validate thermofluid analysis tools and their model improvements, and identify and assess measures for reducing the bypass flow. To achieve thesemore » objectives, tasks were defined to (1) design and construct experiments to generate validation data for software analysis tools, (2) determine the experimental conditions and define the measurement requirements and techniques, (3) generate and analyze the experimental data, (4) validate and improve the thermofluid analysis tools, and (5) identify measures to control the bypass flow and assess its performance in the experiment.« less

A survey, conducted in 1990–1991 on agroforestry and forestry-related systems in eight Midwestern states, showed that three traditional and three nontraditional agroforestry systems are practiced in the region. Of 46 traditional systems reported, most common was agrisilviculture (28), then silvipasture (12) and agrisilvipasture (6). These systems often involved corn, soybeans, and hay planted with tree species for nut, timber, or Christmas tree production, and cattle. Non-traditional agroforestry systems were field windbreaks/shelterbelts (29), treeshrub intercropping systems (21), and boundary plantings (11). These systems involved a variety of northern hardwood species evergreens, and shrubs. There was also a preponderance of specialized systems (97) of growing trees with the production of mushrooms, nuts, syrup, wildlife, and other nonwood products. The survey is exploratory in nature and, although the results may not represent a complete count of people involved with agroforestry in the region, the numbers reported may indicate where a practice may be prevalent. The results reflect the fact that much work still needs to be done by agroforesters in this region. They also provide some basis for further research on more suitable systems, and for identifying other researchable questions on agroforestry for the region. The methodology also made possible a bigger nucleus for networking of agroforesters and other interested people in the Midwest. Finally, although not normally considered as agroforestry, the significance of the other specialized systems reported in this survey is that they offer varied ways of connecting forestry with other activities in a largely agricultural landscape, and that they may even be seen as opportunities for easier transition into agroforestry.

The oval shaped face is generally accepted as having the most beautiful configuration and the ‘golden proportion’ (1:1.618) ideal. Such a configuration can be altered to a square or rectangular shape by an increase in width of the lower face. This broadened morphology can be caused by three anatomical elements: hypertrophy of the masseter muscles, hypertrophy and flaring of the mandibular angles, and hypertrophy or herniation of the buccal fat pads of Bichat. The first two anatomical structures can occasionally become enlarged through work hypertrophy related to malocclusion or dental disease, and the latter displaced through traumatic herniation. Each of these contributing anatomical anomalies can be reduced in size by a single intraoral operative procedure with minimal risk to achieve an aesthetically pleasing oval shaped configuration to the face. There are very few hazards to this procedure and the results are routinely satisfying to both the patient and the surgeon.

A case of intrapericardial giant lymph node hyperplasia (localized hyaline-vascular variant of Castleman's disease) is reported. The large tumor was successfully removed, and at a twelve-year follow-up there are no signs of recurrence. This is the first case reported in the literature of an intrapericardial Castleman's disease localization. Embryologic, surgical, and prognostic implications of this finding are briefly discussed.

The purpose of the fluid dynamics experiments in the MIR (Matched Index of-Refraction) flow system at Idaho National Laboratory (INL) is to develop benchmark databases for the assessment of Computational Fluid Dynamics (CFD) solutions of the momentum equations, scalar mixing, and turbulence models for the flow ratios between coolant channels and bypass gaps in the interstitial regions of typical prismatic standard fuel element (SFE) or upper reflector block geometries of typical Modular High-temperature Gas-cooled Reactors (MHTGR) in the limiting case of negligible buoyancy and constant fluid properties. The experiments use Particle Image Velocimetry (PIV) to measure the velocity fields that will populate the bypass flow study database.

The Unmanned Aircraft Systems Engineering (UASE) team at the University of North Dakota has been conducting research on autonomous target tracking for UAS operations for the last few years. A predictive algorithm was developed to improve and assist in the pointing knowledge and tracking accuracy of a ground based two-axis gimbal system. By utilizing the global positioning system (GPS) data provided by the aircrafts autopilot system, a closed form analytical expression of the gimbal position angles was developed. Before predictive pointing, a method that used the aircrafts last updated location to develop a pointing vector was utilized. This methodology proved to lack in pointing accuracy due to the lack of knowledge of the aircrafts real-time location. The process flow involves multiple subsystems that are used to develop the required rotational angles and velocities of the gimbal system. Therefore, by the time this data is calculated the aircraft will have moved to a different location resulting in the gimbal pointing to an incorrect location lagging the actual target. To accurately track the target the predictive algorithm uses a combination of position and velocity control algorithms to calculate the current and future locations of the aircraft. The position control is used for the initial tracking of the aircraft, while the velocity control allows the gimbal to continually move to each new location without starting and stopping between inputs. In this manner the gimbal is able to “keep up” with the target since the gimbal is in continual motion, as is the aircraft. By storing the aircrafts past known locations in an array, a predicted location of the aircraft is able to be calculated using a various number of past locations to best fit the trajectory. This algorithm has been tested in simulation, mobile ground testing, and flight testing. Initial flight tests were conducted in North Dakota in early July 2010. For the flight tests a camera was attached to the gimbal as it tracked the aircraft. The system showed that the tracking of the aircraft was more accurate than the original non-predictive tracking algorithm.

A high frequency stabilization mount to compensate for small attitude fluctuations is developed for enhanced imaging and pointing systems on Unmanned Aircraft Systems (UAS). This system consists of a custom camera mount, piezoelectric actuators, and a digital controller to actively control flight vibrations. Payload designs that acquire views of the Earth surface and stationary or moving targets require stable cameras for precision viewing. Placing cameras onboard these small aircraft are vital to the Intelligence, Surveillance, and Reconnaissance (ISR) mission of many payload designs. It is necessary to have real time precision viewing imaging systems while in flight, but it is increasingly difficult as the small planes reach higher altitudes. A slight change in the camera angle at high altitudes results in a large shift from the designated target. This project focuses on high frequency analysis for small oscillations rather than large attitude changes that are accomplished with a gimbal. The two systems work together to handle both the high frequency oscillations due to engine vibration and turbulence as well as large low frequency attitude changes. Results will include laboratory testing and simulation data to further prove the effectiveness of this specialized stabilization system.

Purpose: The purpose of this prospective study is to evaluate the postoperative visual acuity, refractive error, intraocular pressure, and status of the posterior capsule in children with traumatic cataracts who undergo extracapsular cataract extraction and insertion of a posterior chamber lens. Methods: Extracapsular cataract extraction and primary endocapsular fixation of a posterior chamber lens implant were performed in eight children (age range, 4–17 years) with unilateral traumatic cataracts. Results: There were no intraoperative complications, and seven of eight eyes achieved 20/40 or greater spectacle visual acuity during an average follow-up interval of 10 months (range, 5–20 months). The average postoperative spherical equivalent refractive error was +0.33 diopter (D) (range, −2.25 to +2.12 D); the average postoperative anisometropia was approximately 1 D (range, 0–2.25 D). In one patient, a coagulase-negative staphylococcal endophthalmitis developed 10 days after surgery. In three eyes that had opacified posterior capsules, YAG laser capsulotomy was performed. Conclusions: These preliminary results suggest that intraocular lens (IOL) implantation may be a safe and effective method of optical correction for children with traumatic cataracts.

One of the great challenges of designing and licensing the Very High Temperature Reactor (VHTR) is to confirm that the intended VHTR analysis tools can be used confidently to make decisions and to assure all that the reactor systems are safe and meet the performance objectives of the Generation IV Program. The research and development (R&D) projects defined in the Next Generation Nuclear Plant (NGNP) Design Methods Development and Validation Program will ensure that the tools used to perform the required calculations and analyses can be trusted. The Methods R&D tasks are designed to ensure that the calculational envelope of the tools used to analyze the VHTR reactor systems encompasses, or is larger than, the operational and transient envelope of the VHTR itself. The Methods R&D focuses on the development of tools to assess the neutronic and thermal fluid behavior of the plant. The fuel behavior and fission product transport models are discussed in the Advanced Gas Reactor (AGR) program plan. Various stress analysis and mechanical design tools will also need to be developed and validated and will ultimately also be included in the Methods R&D Program Plan. The calculational envelope of the neutronics and thermal-fluids software tools intended tomore » be used on the NGNP is defined by the scenarios and phenomena that these tools can calculate with confidence. The software tools can only be used confidently when the results they produce have been shown to be in reasonable agreement with first-principle results, thought-problems, and data that describe the “highly ranked” phenomena inherent in all operational conditions and important accident scenarios for the VHTR.« less

One of the great challenges of designing and licensing the Very High Temperature Reactor (VHTR) is to confirm that the intended VHTR analysis tools can be used confidently to make decisions and to assure all that the reactor systems are safe and meet the performance objectives of the Generation IV Program. The research and development (R&D) projects defined in the Next Generation Nuclear Plant (NGNP) Design Methods Development and Validation Program will ensure that the tools used to perform the required calculations and analyses can be trusted. The Methods R&D tasks are designed to ensure that the calculational envelope of the tools used to analyze the VHTR reactor systems encompasses, or is larger than, the operational and transient envelope of the VHTR itself. The Methods R&D focuses on the development of tools to assess the neutronic and thermal fluid behavior of the plant. The fuel behavior and fission product transport models are discussed in the Advanced Gas Reactor (AGR) program plan. Various stress analysis and mechanical design tools will also need to be developed and validated and will ultimately also be included in the Methods R&D Program Plan. The calculational envelope of the neutronics and thermal-fluids software tools intended tomore » be used on the NGNP is defined by the scenarios and phenomena that these tools can calculate with confidence. The software tools can only be used confidently when the results they produce have been shown to be in reasonable agreement with first-principle results, thought-problems, and data that describe the “highly ranked” phenomena inherent in all operational conditions and important accident scenarios for the VHTR.« less

[1] Thrust faults along the southern margin of the Thaumasia Highlands, Mars, comprise a set of discrete subparallel south verging structures. Previous work proposed that the faults collectively define a narrow Earth‐like orogenic belt composed of a deformed lithospheric section translating southward through Tharsis above a regional decollement. This hypothesis is tested here by comparing topographic slopes across the Thaumasia Highlands to the values required by thrust faulting in a critical taper wedge setting. In general, topographic slopes across the Thaumasia Highlands, 0.418–1.017°, are too shallow for the Martian lithosphere to have deformed as a critical taper wedge, assuming reasonable values for pore fluid pressure ratios and frictional strengths of the wedge material and putative decollement. Combined with the absence of a mechanism to provide the necessary values of horizontal shortening (hundreds of km), nearly lithostatic pore fluid pressure ratios, and nearly frictionless decollements over regional scales on Mars that would be necessary for lithospheric translation as a wedge, the results are consistent with thrust fault deformation across Mars that is not integrated at depth into subhorizontal structures, but which function instead as discrete structures. Citation: Nahm, A. L., and R. A. Schultz (2010), Evaluation of the orogenic belt hypothesis for the formation of the Thaumasia Highlands, Mars, J. Geophys. Res., 115, E04008, doi:10.1029/2009JE003327.

Unmanned Aircraft System (UAS) applications include Intelligence, Surveillance, Target Acquisition, and Reconnaissance (ISTAR) missions over the battlefield, as well as those military and civilian missions that are too “dull, dirty, or dangerous” for humans piloting manned aircraft. However, to faultlessly integrate UAS vehicles into the U.S. National Airspace System (NAS), the Federal Aviation Administration (FAA) requires “an equivalent level of safety, comparable to see-and-avoid requirements for manned aircraft.” In other words, an “ownship” unmanned aerial vehicle (UAV) must be capable of sensing intruder aircraft that are both cooperative (i.e., aircraft equipped with a transponder) and noncooperative [i.e., air traffic that either cannot or choose to not communicate with Air Traffic Control (ATC) and other air traffic, including, crop sprayers, sail planes, gliders, hot air balloons, and flocks of birds], as well as executing autonomous maneuvers to avoid intruder aircraft in mid-air. The University of North Dakota has been actively developing enabling airborne sense and avoid (SAA) technology under a series of projects funded by the Department of Defense (DoD). A Local Airspace Surveillance Terminal (LAST) based on the Automatic Dependent Surveillance – Broadcast (ADS-B) transceiver was designed for recording the flight activities in the Grand Forks regional airspace. Approximately 12710 flight hours of flight data, including both UND Aerospace and non-UND Aerospace flights, was recorded over a span of six weeks. The recorded data was used to characterize the local airspace so that nominal flight paths could be generated for realistic simulations. To prove the robustness of an airborne SAA prototype system also based on the ADS-B transceiver software-in-the-loop (SWIL) and hardware-in-the-loop (HWIL) simulation environments have been developed, particularly for the reliability assessment of a mid-air collision avoidance algorithm. This paper depicts the ADS-B data gathering, post processing, and aircraft encounter modeling methods along with preliminary simulation results.

Three solutions for providing roll and pitch image stabilization on small UAS (Unmanned Aircraft Systems) were developed. Stabilization is provided in the roll and pitch axes through the use of a gimbaled mirror system that maintains a constant orthogonal view of the ground. A consistent orthogonal view provides better quality imagery for visual evaluation as well as image mosaicing. Three different stabilization solutions are presented for qualitative, quantitative, and logistic comparisons. Each system has a unique driving device for stabilization. The first system uses a mechanical gyroscope, the second system uses an infrared horizon sensor, and the third system uses an IMU (Inertial Measurement Unit). Laboratory testing as well as flight testing are discussed.

Free space laser communications provides wide bandwidth and high security capabilities to Unmanned Aircraft Systems (UAS) in order to successfully accomplish Intelligence, Surveillance, Target Acquisition, and Reconnaissance (ISTAR) missions. A practical implementation of a laser-based video communications payload flown by a small UAS aircraft is described as a proof-of-concept. The two-axis gimbal pointing control algorithm calculates the line-of-sight vector in real-time by using differential GPS and IMU information gathered from the UAS vehicle's autopilot so that the laser transmitter in the airborne payload can accurately track a ground-based photodiode array receiver with a known GPS location. One of the future goals of the project is to move from UAS-to-ground communications to UAS-to-UAS free space laser communications.

Unmanned Aircraft Systems (UAS) have been used in many military and civilian applications, particularly surveillance. One of the best ways to use the capacity of a UAS imaging system is by constructing a mosaic of the recorded video. In this paper, we present a novel algorithm to calculate a super-resolution mosaic for UAS, which is both fast and robust. In this algorithm, the features points between frames are found using SIFT (Scale-Invariant Feature Transform), and then RANSAC (Random Sample Consensus) is used to estimate the homography between two consecutive frames. Next, a low-resolution (LR) mosaic is computed. LR images are extracted from the LR mosaic, and then they are subtracted from the input frames to form LR error images. These images are used to compute an error mosaic. The regularization technique uses Huber prior information and is added to the error mosaic to form the superresolution (SR) mosaic. The proposed algorithm was implemented using both a GPU (Graphics Processing Unit) and a CPU (Central Processing Unit). The first part of the algorithm, which is the construction of the LR mosaic, is performed by the GPU, and the rest is performed by the CPU. As a result, there is a significant speed-up of the algorithm. The proposed algorithm has been tested in both the infrared (IR) and visible spectra, using real and synthetic data. The results for all these cases show a great improvement in resolution, with a PSNR of 41.10 dB for synthetic data, and greater visual detail for the real UAV surveillance data.

Unmanned Aircraft Systems (UAS) have been used in many military and civil applications, particularly surveillance. One of the best ways to use the capacity of a UAS imaging system is by constructing a mosaic of the recorded video. This paper presents a novel algorithm for the construction of superresolution mosaicking. The algorithm is based on the Levenberg Marquardt (LM) method. Hubert prior is used together with four different cliques to deal with the ill-conditioned inverse problem and to preserve edges. Furthermore, the Lagrange multiplier is compute without using sparse matrices. We present the results with synthetic and real UAS surveillance data, resulting in a great improvement of the visual resolution. For the case of synthetic images, we obtained a PSNR of 47.0 dB, as well as a significant increase in the details visible for the case of real UAS frames in only ten iterations.

With the resurgence of nuclear power and increased interest in advanced nuclear reactors as an option to supply abundant energy without the associated greenhouse gas emissions of the more conventional fossil fuel energy sources, there is a need to establish internationally recognized standards for the verification and validation (V&V) of software used to calculate the thermal-hydraulic behavior of advanced reactor designs for both normal operation and hypothetical accident conditions. To address this need, ASME (American Society of Mechanical Engineers) Standards and Certification has established the V&V 30 Committee, under the jurisdiction of the V&V Standards Committee, to develop a consensus standard for verification and validation of software used for design and analysis of advanced reactor systems. The initial focus of this committee will be on the V&V of system analysis and computational fluid dynamics (CFD) software for nuclear applications. To limit the scope of the effort, the committee will further limit its focus to software to be used in the licensing of High-Temperature Gas-Cooled Reactors. In this framework, the Standard should conform to Nuclear Regulatory Commission (NRC) and other regulatory practices, procedures and methods for licensing of nuclear power plants as embodied in the United States (U.S.) Code of Federal Regulations and other pertinent documents such as Regulatory Guide 1.203, “Transient and Accident Analysis Methods” and NUREG-0800, “NRC Standard Review Plan”. In addition, the Standard should be consistent with applicable sections of ASME NQA-1-2008 “Quality Assurance Requirements for Nuclear Facility Applications (QA)”. This paper describes the general requirements for the proposed V&V 30 Standard, which includes; (a) applicable NRC and other regulatory requirements for defining the operational and accident domain of a nuclear system that must be considered if the system is to be licensed, (b) the corresponding calculation domain of the software that should encompass the nuclear operational and accident domain to be used to study the system behavior for licensing purposes, (c) the definition of the scaled experimental data set required to provide the basis for validating the software, (d) the ensemble of experimental data sets required to populate the validation matrix for the software in question, and (e) the practices and procedures to be used when applying a validation standard. Although this initial effort will focus on software for licensing of High-Temperature Gas-Cooled Reactors, it is anticipated that the practices and procedures developed for this Standard can eventually be extended to other nuclear and non-nuclear applications.

Images obtained through the gel electrophoresis technique contain important genetic information. However, due to degradations and abnormalities from which these images suffer, extracting this information can be a tedious task and may lead to reproducibility issues. Image processing techniques that are commonly used to analyze gel electrophoresis images require three main steps: band detection, band matching, and quantification. Although several techniques were proposed to automate all steps fully, gel image analysis still requires researchers to extract information manually. This type of extraction is time consuming and subject to human errors. This paper proposes a fully automated system to analyze the gel electrophoresis images. This system involves four main steps: lane separation, lane segmentation, band detection, and data quantification.

Advanced light water reactor systems are designed to use passive emergency core cooling systems with horizontal pipes that provide highly subcooled water from water storage tanks or passive heat exchangers to the reactor vessel core under accident conditions. Because passive systems are driven by density gradients, the horizontal pipes often do not flow full and thus have a free surface that is exposed to saturated steam and stratified flow is present. The subcooled water flows into the reactor vessel via the downcomer—which is an annular region separated from the core by a cylindrical, steel, inner liner. Under accident conditions, where the horizontal pipes are only partially full, both saturated water and saturated steam from the downcomer are likely to be present in the pipe. The saturated water is quasi-static and the fraction of the free surface that is saturated water is dictated by the physics of the flow. The saturated steam is usually flowing in the countercurrent direction to the subcooled water. Consequently the flow may be a three-layered system with saturated steam over a static saturated liquid layer over a flowing subcooled layer. The conditions leading to a saturated liquid layer that separates the saturated steam from flowing subcooled water are explored. The variables that influence the formation of the saturated liquid layer and enable the saturated layer to be maintained for a spectrum of conditions, including steam flow in the countercurrent direction to the subcooled water, are derived, and compared to experimental data. Conclusions regarding this type of flow are given. Finally, typical steam flow velocities that may induce wave-bridging, leading to condensation-induced-water hammer, are identified.

An axillodistal abdominal aorta bypass graft is proposed as an alterative procedure for revascularization of the lower limbs when intraabdominal and intrathoracic approaches are not feasible. This simple and safe procedure is proposed instead of the axillobifemoral bypass graft for the treatment of selected patients with abdominal aortic occlusive or aneurysmal disease and aortic graft infection. A case of a patient who underwent axilloabdominal aortic grafting because of a ruptured infrarenal abdominal aortic aneurysm, combined with severe chronic obstructive pulmonary disease, is reported.

Two main challenges lie in tracking the partially occluded targets in a high-similarity background: 1) similar intensities increase the difficulty of discriminating targets from the background, and 2) occlusion (illumination and shape) decreases the relativity of targets to templates. In this paper, a novel eigenspace-based hybrid particle filter tracking method combined with online non-local appearance model is proposed to track the objects under highly similar environment with occlusions. By on-line training of the templates through non-local methods to generate the active appearance model, it is more likely find the maximum-likelihood distribution correctly. The projective transformation is utilized to cover all of the possible motion factors between the templates. The extended and unscented Kalman filters are switched to update the particles according to the linearity of the motion parameters. The experiment results show the effectiveness of our algorithm while dealing with occluded target in a high-similarity background.

The United States Department of Energy is promoting the resurgence of nuclear power in the U. S. for both electrical power generation and production of process heat required for industrial processes such as the manufacture of hydrogen for use as a fuel in automobiles. The DOE project is called the next generation nuclear plant (NGNP) and is based on a Generation IV reactor concept called the very high temperature reactor (VHTR), which will use helium as the coolant at temperatures ranging from 450 oC to perhaps 1000 oC. While computational fluid dynamics (CFD) has not been used for past safety analysis for nuclear reactors in the U. S., it is being considered for safety analysis for existing and future reactors. It is fully recognized that CFD simulation codes will have to be validated for flow physics reasonably close to actual fluid dynamic conditions expected in normal and accident operational situations. To this end, experimental data have been obtained in a scaled model of a narrow slice of the lower plenum of a prismatic VHTR. The present report presents results of CFD examinations of these data to explore potential issues with the geometry, the initial conditions, the flow dynamics and the data needed to fully specify the inlet and boundary conditions; results for several turbulence models are examined. Issues are addressed and recommendations about the data are made.

The Unmanned Aircraft Systems Engineering (UASE) laboratory at the University of North Dakota (UND) has developed an autonomous system tracking device for an aircraft transmitting its Global Positioning System (GPS) coordinates. This pointing system uses GPS coordinates from the aircraft to point directional communication antennas. The pointing algorithm is a closed form analytical expression that specifies the rotation angles of the gimbal. This device also eliminates the presence of ground personnel required to angle the directional antennas at the aircraft. The directional antennas provide better signal bandwidth and strength for communication purposes. Through the use of already developed technology and payload systems, the integration of this technology proves to be a valuable addition to existing unmanned aircrafts and payloads.