Radiation Enhanced Absorption of Frank Loops by Nanovoids in Cu

DOE PAGES

Chen, Youxing; Zhang, Xinghang; Wang, Jian

2016-11-01

Neutron and heavy ion irradiation generally induces voids in metallic materials, and continuous radiations typically result in void swelling and mechanical failure of the irradiated materials. Recent experiments showed that nanovoids in nanotwinned copper could act as sinks for radiation-induced Frank loops, significantly mitigating radiation damage [Y. Chen et al., Nat. Commun. 6:7036 (2015)]. In this paper, we report on structural evolution of Frank loops under cascades and address the role of nanovoids in absorbing Frank loops in detail by using molecular dynamics simulations. Results show that a stand-alone Frank loop is stable under cascades. When Frank loops are adjacentmore » to nanovoids, the diffusion of a group of atoms from the loop into nanovoids is accomplished via the formation and propagation of dislocation loops. The loop-nanovoid interactions result in the shrinkage of the nanovoids and the Frank loops.« less

The results of the investigations of Russian Research Center - {open_quotes}Kurchatov Institute{close_quotes} on molten salt applications to problems of nuclear energy systems

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

Novikov, V.M.

1995-10-01

The results of investigations on molten salt (MS) applications to problems of nuclear energy systems that have been conducted in Russian Research {open_quotes}Kurchatov Institute{close_quotes} are presented and discussed. The spectrum of these investigations is rather broad and covers the following items: physical characteristics of molten salt nuclear energy systems (MSNES); nuclear and radiation safety of MSNES; construction materials compatible with MS of different compositions; technological aspects of MS loops; in-reactor loop testing. It is shown that main findings of completed program support the conclusion that there are no physical nor technological obstacles on way of MS application to different nuclearmore » energy systems.« less

Plastic flexible films waste management - A state of art review.

PubMed

Horodytska, O; Valdés, F J; Fullana, A

2018-04-21

Plastic flexible films are increasingly used in many applications due to their lightness and versatility. In 2014, the amount of plastic films represented 34% of total plastic packaging produced in UK. The flexible film waste generation rises according to the increase in number of applications. Currently, in developed countries, about 50% of plastics in domestic waste are films. Moreover, about 615,000 tonnes of agricultural flexible waste are generated in the EU every year. A review of plastic films recycling has been conducted in order to detect the shortcomings and establish guidelines for future research. This paper reviews plastic films waste management technologies from two different sources: post-industrial and post-consumer. Clean and homogeneous post-industrial waste is recycled through closed-loop or open-loop mechanical processes. The main differences between these methods are the quality and the application of the recycled materials. Further research should be focused on closing the loops to obtain the highest environmental benefits of recycling. This could be accomplished through minimizing the material degradation during mechanical processes. Regarding post-consumer waste, flexible films from agricultural and packaging sectors have been assessed. The agricultural films and commercial and industrial flexible packaging are recycled through open-loop mechanical recycling due to existing selective waste collection routes. Nevertheless, the contamination from the use phase adversely affects the quality of recycled plastics. Therefore, upgrading of current washing lines is required. On the other hand, household flexible packaging shows the lowest recycling rates mainly because of inefficient sorting technologies. Delamination and compatibilization methods should be further developed to ensure the recycling of multilayer films. Finally, Life Cycle Assessment (LCA) studies on waste management have been reviewed. A lack of thorough LCA on plastic films waste management systems was identified. Copyright © 2018 Elsevier Ltd. All rights reserved.

MaTrace: tracing the fate of materials over time and across products in open-loop recycling.

PubMed

Nakamura, Shinichiro; Kondo, Yasushi; Kagawa, Shigemi; Matsubae, Kazuyo; Nakajima, Kenichi; Nagasaka, Tetsuya

2014-07-01

Even for metals, open-loop recycling is more common than closed-loop recycling due, among other factors, to the degradation of quality in the end-of-life (EoL) phase. Open-loop recycling is subject to loss of functionality of original materials, dissipation in forms that are difficult to recover, and recovered metals might need dilution with primary metals to meet quality requirements. Sustainable management of metal resources calls for the minimization of these losses. Imperative to this is quantitative tracking of the fate of materials across different stages, products, and losses. A new input-output analysis (IO) based model of dynamic material flow analysis (MFA) is presented that can trace the fate of materials over time and across products in open-loop recycling taking explicit consideration of losses and the quality of scrap into account. Application to car steel recovered from EoL vehicles (ELV) showed that after 50 years around 80% of the steel is used in products, mostly buildings and civil engineering (infrastructure), with the rest mostly resided in unrecovered obsolete infrastructure and refinery losses. Sensitivity analysis was conducted to evaluate the effects of changes in product lifespan, and the quality of scrap.

Hybrid nodal loop metal: Unconventional magnetoresponse and material realization

NASA Astrophysics Data System (ADS)

Zhang, Xiaoming; Yu, Zhi-Ming; Lu, Yunhao; Sheng, Xian-Lei; Yang, Hui Ying; Yang, Shengyuan A.

2018-03-01

A nodal loop is formed by a band crossing along a one-dimensional closed manifold, with each point on the loop a linear nodal point in the transverse dimensions, and can be classified as type I or type II depending on the band dispersion. Here, we propose a class of nodal loops composed of both type-I and type-II points, which are hence termed as hybrid nodal loops. Based on first-principles calculations, we predict the realization of such loops in the existing electride material Ca2As . For a hybrid loop, the Fermi surface consists of coexisting electron and hole pockets that touch at isolated points for an extended range of Fermi energies, without the need for fine-tuning. This leads to unconventional magnetic responses, including the zero-field magnetic breakdown and the momentum-space Klein tunneling observable in the magnetic quantum oscillations, as well as the peculiar anisotropy in the cyclotron resonance.

Development of a Scanning Microscale Fast Neutron Irradiation Platform for Examining the Correlation Between Local Neutron Damage and Graphite Microstructure

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

Pinhero, Patrick; Windes, William

2015-03-10

The fast particle radiation damage effect of graphite, a main material in current and future nuclear reactors, has significant influence on the utilization of this material in fission and fusion plants. Atoms on graphite crystals can be easily replaced or dislocated by fast protons and result in interstitials and vacancies. The currently accepted model indicates that after most of the interstitials recombine with vacancies, surviving interstitials form clusters and furthermore gather to create loops with each other between layers. Meanwhile, surviving vacancies and interstitials form dislocation loops on the layers. The growth of these inserted layers cause the dimensional increase,more » i.e. swelling, of graphite. Interstitial and vacancy dislocation loops have been reported and they can easily been observed by electron microscope. However, observation of the intermediate atom clusters becomes is paramount in helping prove this model. We utilize fast protons generated from the University of Missouri Research Reactor (MURR) cyclotron to irradiate highly- oriented pyrolytic graphite (HOPG) as target for this research. Post-irradiation examination (PIE) of dosed targets with high-resolution transmission electron microscopy (HRTEM) has permit observation and analysis of clusters and dislocation loops to support the proposed theory. Another part of the research is to validate M.I. Heggie’s Ruck and Tuck model, which introduced graphite layers may fold under fast particle irradiation. Again, we employed microscopy to image irradiated specimens to determine how the extent of Ruck and Tuck by calculating the number of folds as a function of dose. Our most significant accomplishment is the invention of a novel class of high-intensity pure beta-emitters for long-term lightweight batteries. We have filed four invention disclosure records based on the research conducted in this project. These batteries are lightweight because they consist of carbon and tritium and can be fabricated to conform to many geometric shapes. In addition, we have published eight peer-reviewed American Nuclear Society (ANS) transactions, and presented our findings at ANS National Meetings, and several universities.« less

Means for accommodating large overstrain in lead wires. [by storing extra length of wire in stretchable loop

NASA Technical Reports Server (NTRS)

Rumble, C. V.; Driscoll, K. L. (Inventor)

1974-01-01

An electrical wire is reported along whose length loops are formed at intervals and retained in a plastic capsule that allows unfolding of the loop when tension is exerted on the opposite ends of the wire. The capsule is formed by encompassing each loop with a sleeve of heat shrinkable synthetic plastic material which overlaps the loop and heat shrinking the overlapping portions. Thus, a length of electrical wire is formed which stores extra lengths of wire in the quantity needed to match the expected stretching of materials or elements such as ropes, cords and the like of high elongation to which the electrical wire may be attached.

Behavior of sandhill cranes harnessed with different satellite transmitters

USGS Publications Warehouse

Olsen, Glenn H.; Ellis, D.H.; Landfried, S.E.; Miller, L.H.; Klugman, S.S.; Fuller, M.R.; Vermillion, C.H.

1992-01-01

The effectiveness of various attachment methods and designs of platform transmitting terminals (PTT's) was tested on captive sandhill cranes (Grus canadensis) at the Patuxent Wildlife Research Center, Laurel, Maryland, during 1989-91. Combinations of attachment and transmitter designs included neoprene cord harness with batteries separate from the transmitter (2 harness designs), Teflon ribbon harness with batteries incorporated into the transmitter package (4 transmitter models), and a package attached directly to the bird with epoxy glue only. Physical effects seen on cranes wearing PTT's ranged from skin lacerations (caused by rubbing of harness material) to no observed effects (other than feather wear). The most successful harness material and design utilized a Teflon ribbon harness with the 4 ribbon ends from the transmitter forming a neck loop and a body loop joined at the sternum. Time spent by sandhill cranes performing most activities did not change after transmitter attachment using this harness method.

FLiNaK Compatability Studies with Inconel 600 and Silicon Carbide

DOE PAGES

Yoder, Jr, Graydon L.; Heatherly, Dennis Wayne; Wilson, Dane F.; ...

2016-07-26

A small liquid fluoride salt test apparatus has been constructed and testing conducted to examine the compatibility of SiC, Inconel 600, and a spiral wound gasket material in FLiNaK salt. These tests were conducted to test materials and sealing systems that would be used in a FLiNaK salt test loop. Three months of testing at 700oC was used to assure that these materials and seals would be acceptable operating under expected test loop conditions. The SiC specimens showed little or no change over the test period while the spiral wound gasket material showed no degradation, except for the possibility ofmore » salt seeping into the outermost spirals of the gasket. The Inconel 600 specimens showed regions of voiding which penetrated the specimen surface to about 250 m in depth. Analysis indicated that the salt had leached chrome from the Inconel surface as was expected for this material. Because the test loop will have a limited working lifetime, it was concluded that these materials would be satisfactory for loop construction.« less

Structural defect accumulation in tungsten and tungsten-5wt.% tantalum under incremental proton damage

NASA Astrophysics Data System (ADS)

Ipatova, I.; Harrison, R. W.; Wady, P. T.; Shubeita, S. M.; Terentyev, D.; Donnelly, S. E.; Jimenez-Melero, E.

2018-04-01

We have performed proton irradiation of W and W-5wt.%Ta materials at 350 °C with a step-wise damage level increase up to 0.7 dpa and using two beam energies, namely 40 keV and 3 MeV, in order to probe the accumulation of radiation-induced lattice damage in these materials. Interstitial-type a/2 <111> dislocation loops are formed under irradiation, and their size increases in W-5Ta up to a loop width of 21 ± 4 nm at 0.3 dpa, where loop saturation takes place. In contrast, the loop length in W increases progressively up to 183 ± 50 nm at 0.7 dpa, whereas the loop width remains relatively constant at 29 ± 7 nm at >0.3 dpa, giving rise to dislocation strings. The dislocation loops and tangles are observed in both materials examined after a 3 MeV proton irradiation at 350 °C. Ta doping delays the evolution of radiation-induced dislocation structures in W, and can consequently impact the hydrogen isotope retention under plasma exposure.

Magnetic forces in high-Tc superconducting bearings

NASA Technical Reports Server (NTRS)

Moon, F. C.

1991-01-01

In September 1987, researchers at Cornell levitated a small rotor on superconducting bearings at 10,000 rpm. In April 1989, a speed of 120,000 rpm was achieved in a passive bearing with no active control. The bearing material used was YBa2Cu307. There is no evidence that the rotation speed has any significant effect on the lift force. Magnetic force measurements between a permanent rare-earth magnet and high T(sub c) superconducting material versus vertical and lateral displacements were made. A large hysteresis loop results for large displacements, while minor loops result for small displacements. These minor loops seem to give a slope proportional to the magnetic stiffness, and are probably indicative of flux pinning forces. Experiments of rotary speed versus time show a linear decay in a vacuum. Measurements of magnetic dipole over a high-T(sub c) superconducting disc of YBCO show that the lateral vibrations of levitated rotors were measured which indicates that transverse flux motion in the superconductor will create dissipation. As a result of these force measurements, an optimum shape for the superconductor bearing pads which gives good lateral and axial stability was designed. Recent force measurements on melt-quench processed superconductors indicate a substantial increase in levitation force and magnetic stiffness over free sintered materials. As a result, application of high-T(sub c) superconducting bearings are beginning to show great promise at this time.

State demonstration project : loop detectors.

DOT National Transportation Integrated Search

1985-01-01

The Virginia Department of Highways and Transportation frequently utilizes induction loops in its vehicle detector systems. Although not documented, there have been many instances of loop failure; therefore, the practices and materials used by the De...

Design and Calibration of the US Army Research Laboratory (ARL) Closed Loop Laboratory Radio Frequency (RF) Propagation Section

DTIC Science & Technology

2016-10-01

ARL-TR-7860 ● OCT 2016 US Army Research Laboratory Design and Calibration of the US Army Research Laboratory (ARL) Closed Loop ...ARL-TR-7860 ● OCT 2016 US Army Research Laboratory Design and Calibration of the US Army Research Laboratory (ARL) Closed Loop Laboratory...Design and Calibration of the US Army Research Laboratory (ARL) Closed Loop Laboratory Radio Frequency (RF) Propagation Section 5a. CONTRACT NUMBER

Attrition Rate of Oxygen Carriers in Chemical Looping Combustion Systems

NASA Astrophysics Data System (ADS)

Feilen, Harry Martin

This project developed an evaluation methodology for determining, accurately and rapidly, the attrition resistance of oxygen carrier materials used in chemical looping technologies. Existing test protocols, to evaluate attrition resistance of granular materials, are conducted under non-reactive and ambient temperature conditions. They do not accurately reflect the actual behavior under the unique process conditions of chemical looping, including high temperatures and cyclic operation between oxidizing and reducing atmospheres. This project developed a test method and equipment that represented a significant improvement over existing protocols. Experimental results obtained from this project have shown that hematite exhibits different modes of attrition, including both due to mechanical stresses and due to structural changes in the particles due to chemical reaction at high temperature. The test methodology has also proven effective in providing reactivity changes of the material with continued use, a property, which in addition to attrition, determines material life. Consumption/replacement cost due to attrition or loss of reactivity is a critical factor in the economic application of the chemical looping technology. This test method will allow rapid evaluation of a wide range of materials that are best suited for this technology. The most important anticipated public benefit of this project is the acceleration of the development of chemical looping technology for lowering greenhouse gas emissions from fossil fuel combustion.

Installation report, state demonstration project, loop detectors.

DOT National Transportation Integrated Search

1982-01-01

The Virginia Department of Highways and Transportation frequently utilizes induction loops in its vehicle detector systems. Although not documented, there have been many instances of loop failure; therefore, the practices and materials used by the De...

Material Data Representation of Hysteresis Loops for Hastelloy X Using Artificial Neural Networks

NASA Technical Reports Server (NTRS)

Alam, Javed; Berke, Laszlo; Murthy, Pappu L. N.

1993-01-01

The artificial neural network (ANN) model proposed by Rumelhart, Hinton, and Williams is applied to develop a functional approximation of material data in the form of hysteresis loops from a nickel-base superalloy, Hastelloy X. Several different ANN configurations are used to model hysteresis loops at different cycles for this alloy. The ANN models were successful in reproducing the hysteresis loops used for its training. However, because of sharp bends at the two ends of hysteresis loops, a drift occurs at the corners of the loops where loading changes to unloading and vice versa (the sharp bends occurred when the stress-strain curves were reproduced by adding stress increments to the preceding values of the stresses). Therefore, it is possible only to reproduce half of the loading path. The generalization capability of the network was tested by using additional data for two other hysteresis loops at different cycles. The results were in good agreement. Also, the use of ANN led to a data compression ratio of approximately 22:1.

Designing Hysteresis with Dipolar Chains

NASA Astrophysics Data System (ADS)

Concha, Andrés; Aguayo, David; Mellado, Paula

2018-04-01

Materials that have hysteretic response to an external field are essential in modern information storage and processing technologies. A myriad of magnetization curves of several natural and artificial materials have previously been measured and each has found a particular mechanism that accounts for it. However, a phenomenological model that captures all the hysteresis loops and at the same time provides a simple way to design the magnetic response of a material while remaining minimal is missing. Here, we propose and experimentally demonstrate an elementary method to engineer hysteresis loops in metamaterials built out of dipolar chains. We show that by tuning the interactions of the system and its geometry we can shape the hysteresis loop which allows for the design of the softness of a magnetic material at will. Additionally, this mechanism allows for the control of the number of loops aimed to realize multiple-valued logic technologies. Our findings pave the way for the rational design of hysteretical responses in a variety of physical systems such as dipolar cold atoms, ferroelectrics, or artificial magnetic lattices, among others.

Designing Hysteresis with Dipolar Chains.

PubMed

Concha, Andrés; Aguayo, David; Mellado, Paula

2018-04-13

Materials that have hysteretic response to an external field are essential in modern information storage and processing technologies. A myriad of magnetization curves of several natural and artificial materials have previously been measured and each has found a particular mechanism that accounts for it. However, a phenomenological model that captures all the hysteresis loops and at the same time provides a simple way to design the magnetic response of a material while remaining minimal is missing. Here, we propose and experimentally demonstrate an elementary method to engineer hysteresis loops in metamaterials built out of dipolar chains. We show that by tuning the interactions of the system and its geometry we can shape the hysteresis loop which allows for the design of the softness of a magnetic material at will. Additionally, this mechanism allows for the control of the number of loops aimed to realize multiple-valued logic technologies. Our findings pave the way for the rational design of hysteretical responses in a variety of physical systems such as dipolar cold atoms, ferroelectrics, or artificial magnetic lattices, among others.

Design of Test Loops for Forced Convection Heat Transfer Studies at Supercritical State

NASA Astrophysics Data System (ADS)

Balouch, Masih N.

Worldwide research is being conducted to improve the efficiency of nuclear power plants by using supercritical water (SCW) as the working fluid. One such SCW reactor considered for future development is the CANDU-Supercritical Water Reactor (CANDU-SCWR). For safe and accurate design of the CANDU-SCWR, a detailed knowledge of forced-convection heat transfer in SCW is required. For this purpose, two supercritical fluid loops, i.e. a SCW loop and an R-134a loop are developed at Carleton University. The SCW loop is designed to operate at pressures as high as 28 MPa, temperatures up to 600 °C and mass fluxes of up to 3000 kg/m2s. The R-134a loop is designed to operate at pressures as high as 6 MPa, temperatures up to 140 °C and mass fluxes in the range of 500-6000 kg/m2s. The test loops designs allow for up to 300 kW of heating power to be imparted to the fluid. Both test loops are of the closed-loop design, where flow circulation is achieved by a centrifugal pump in the SCW loop and three parallel-connected gear pumps in the R-134a loop, respectively. The test loops are pressurized using a high-pressure nitrogen cylinder and accumulator assembly, which allows independent control of the pressure, while simultaneously dampening pump induced pressure fluctuations. Heat exchangers located upstream of the pumps control the fluid temperature in the test loops. Strategically located measuring instrumentation provides information on the flow rate, pressure and temperature in the test loops. The test loops have been designed to accommodate a variety of test-section geometries, ranging from a straight circular tube to a seven-rod bundle, achieving heat fluxes up to 2.5 MW/m2 depending on the test-section geometry. The design of both test loops allows for easy reconfiguration of the test-section orientation relative to the gravitational direction. All the test sections are of the directly-heated design, where electric current passing through the pressure retaining walls of the test sections provides the Joule heating required to heat up the fluid to supercritical conditions. A high-temperature dielectric gasket isolates the current carrying parts of the test section from the rest of the assembly. Temperature and pressure drop data are collected at the inlet and outlet, and along the heated length of the test section. The test loops and test sections are designed according to American Society of Mechanical Engineers (ASME) Pressure Piping B31.1, and Boiler and Pressure Vessel Code, Section VIII-Division 1 rules. The final test loops and test sections assemblies are certified by Technical Standards and Safety Authority (TSSA). Every attempt is made to use off-the-shelf components where possible in order to streamline the design process and reduce costs. Following a rigorous selection process, stainless steel Types 316 and 316H are selected as the construction materials for the test loops, and Inconel 625 is selected as the construction material for the test sections. This thesis describes the design of the SCW and R-134a loops along with the three test-section geometries (i.e., tubular, annular and bundle designs).

INTESTINAL OBSTRUCTION

PubMed Central

Whipple, G. H.; Stone, H. B.; Bernheim, B. M.

1913-01-01

Closed duodenal loops may be made in dogs by ligatures placed just below the pancreatic duct and just beyond the duodenojejunal junction, together with a posterior gastro-enterostomy. These closed duodenal loop dogs die with symptoms like those of patients suffering from volvulus or high intestinal obstruction. This duodenal loop may simulate closely a volvulus in which there has been no vascular disturbance. Dogs with closed duodenal loops which have been washed out carefully survive a little longer on the average than animals with unwashed loops. The duration of life in the first instance is one to three days, with an average of about forty-eight hours. The dogs usually lose considerable fluid by vomiting and diarrhea. A weak pulse, low blood pressure and temperature are usually conspicuous in the last stages. Autopsy shows more or less splanchnic congestion which may be most marked in the mucosa of the upper small intestine. The peritoneum is usually clear and the closed loop may be distended with thin fluid, or collapsed, and contain only a small amount of pasty brown material. The mucosa of the loop may show ulceration and even perforation, but in the majority of cases it is intact and exhibits only a moderate congestion. Simple intestinal obstruction added to a closed duodenal loop does not modify the result in any manner, but it may hasten the fatal outcome. The liver plays no essential role as a protective agent against this poison, for a dog with an Eck fistula may live three days with a closed loop. A normal dog reacts to intraportal injection and to intravenous injection of the toxic substance in an identical manner. Drainage of this loop under certain conditions may not interfere with the general health over a period of weeks or months. Excision of the part of the duodenum included in this loop causes no disturbance. The material from the closed duodenal loops contains no bile, pancreatic juice, gastric juice, or split products from the food. It can be formed in no other way than by the activity of the intestinal mucosa and the growth of the intestinal bacteria. This material after dilution, autolysis, sterilization, and filtration produces a characteristic effect when introduced intravenously. When in toxic doses it causes a profound drop in blood pressure, general collapse, drop in temperature, salivation, vomiting, and profuse diarrhea, which is often blood-stained. Splanchnic congestion is the conspicuous feature at autopsy and shows especially in the villi of the duodenal and jejunal mucosæ. Adrenalin, during this period of low blood pressure and splanchnic congestion, will cause the usual reaction when given intravenously, but applied locally or given intravenously it causes no bleaching of the engorged intestinal mucosa. Secretin is not found in the duodenal loop fluid, and the loop material does not influence the pancreatic secretion. Intraportal injection of the toxic material gives a reaction similar to intravenous injection. Intraperitoneal and subcutaneous injections produce a relatively slow reaction which closely resembles the picture seen in the closed duodenal loop dog. In both cases there is a relatively slow absorption, but the splanchnic congestion and other findings, though less intense, are present in both groups. There seems, therefore, to be no escape from the conclusion that a poisonous substance is formed in this closed duodenal loop which is absorbed from it and causes intoxication and death. Injection of this toxic substance into a normal dog gives intoxication and a reaction more intense but similar to that developing in a closed-loop dog. PMID:19867644

46 CFR 160.060-3 - Materials-standard vests.

Code of Federal Regulations, 2010 CFR

2010-10-01

... Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) EQUIPMENT, CONSTRUCTION, AND MATERIALS..., Adult and Child § 160.060-3 Materials—standard vests. (a) General. All components used in the... body strap loops. The tie tapes and body strap loops for both adult and child sizes must be 3/4-inch...

Response of Nuclear Power Plant Instrumentation Cables Exposed to Fire Conditions.

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

Muna, Alice Baca; LaFleur, Chris Bensdotter; Brooks, Dusty Marie

This report presents the results of instrumentation cable tests sponsored by the US Nuclear Regulatory Commission (NRC) Office of Nuclear Regulatory Research and performed at Sandia National Laboratories (SNL). The goal of the tests was to assess thermal and electrical response behavior under fire-exposure conditions for instrumentation cables and circuits. The test objective was to assess how severe radiant heating conditions surrounding an instrumentation cable affect current or voltage signals in an instrumentation circuit. A total of thirty-nine small-scale tests were conducted. Ten different instrumentation cables were tested, ranging from one conductor to eight-twisted pairs. Because the focus of themore » tests was thermoset (TS) cables, only two of the ten cables had thermoplastic (TP) insulation and jacket material and the remaining eight cables were one of three different TS insulation and jacket material. Two instrumentation cables from previous cable fire testing were included, one TS and one TP. Three test circuits were used to simulate instrumentation circuits present in nuclear power plants: a 4–20 mA current loop, a 10–50 mA current loop and a 1–5 VDC voltage loop. A regression analysis was conducted to determine key variables affecting signal leakage time.« less

Research Opportunities Supporting the Vision for Space Exploration from the Transformation of the Former Microgravity Materials Science Program

NASA Technical Reports Server (NTRS)

Clinton, R. G., Jr.; Szofran, Frank; Bassler, Julie A.; Schlagheck, Ronald A.; Cook, Mary Beth

2005-01-01

The Microgravity Materials Science Program established a strong research capability through partnerships between NASA and the scientific research community. With the announcement of the vision for space exploration, additional emphasis in strategic materials science areas was necessary. The President's Commission recognized that achieving its exploration objectives would require significant technical innovation, research, and development in focal areas defined as "enabling technologies." Among the 17 enabling technologies identified for initial focus were: advanced structures, advanced power and propulsion; closed-loop life support and habitability; extravehicular activity systems; autonomous systems and robotics; scientific data collection and analysis, biomedical risk mitigation; and planetary in situ resource utilization. Mission success may depend upon use of local resources to fabricate a replacement part to repair a critical system. Future propulsion systems will require materials with a wide range of mechanical, thermophysical, and thermochemical properties, many of them well beyond capabilities of today's materials systems. Materials challenges have also been identified by experts working to develop advanced life support systems. In responding to the vision for space exploration, the Microgravity Materials Science Program aggressively transformed its research portfolio and focused materials science areas of emphasis to include space radiation shielding; in situ fabrication and repair for life support systems; in situ resource utilization for life support consumables; and advanced materials for exploration, including materials science for space propulsion systems and for life support systems. The purpose of this paper is to inform the scientific community of these new research directions and opportunities to utilize their materials science expertise and capabilities to support the vision for space exploration.

Cyclic softening based on dislocation annihilation at sub-cell boundary for SA333 Grade-6 C-Mn steel

NASA Astrophysics Data System (ADS)

Bhattacharjee, S.; Dhar, S.; Acharyya, S. K.; Gupta, S. K.

2018-01-01

In this work, the response of SA333 Grade-6 C-Mn steel subjected to uniaxial and in-phase biaxial tension-torsion cyclic loading is experimented and an attempt is made to model the material behaviour. Experimentally observed cyclic softening is modelled based on ‘dislocation annihilation at low angle grain boundary’, while Ohno-Wang kinematic hardening rule is used to simulate the stress-strain hysteresis loops. The relevant material parameters are extracted from the appropriate experimental results and metallurgical investigations. The material model is plugged as user material subroutine into ABAQUS FE platform to simulate pre-saturation low cycle fatigue loops with cyclic softening and other cyclic plastic behaviour under prescribed loading. The stress-strain hysteresis loops and peak stress with cycles were compared with the experimental results and good agreements between experimental and simulated results validated the material model.

Magnetization reversal modes in fourfold Co nano-wire systems

NASA Astrophysics Data System (ADS)

Blachowicz, T.; Ehrmann, A.

2015-09-01

Magnetic nano-wire systems are, as well as other patterned magnetic structures, of special interest for novel applications, such as magnetic storage media. In these systems, the coupling between neighbouring magnetic units is most important for the magnetization reversal process of the complete system, leading to a variety of magnetization reversal mechanisms. This article examines the influence of the magnetic material on hysteresis loop shape, coercive field, and magnetization reversal modes. While iron nano-wire systems exhibit flat or one-step hysteresis loops, systems consisting of cobalt nano-wires show hysteresis loops with several longitudinal steps and transverse peaks, correlated to a rich spectrum of magnetization reversal mechanisms. We show that changing the material parameters while the system geometry stays identical can lead to completely different hysteresis loops and reversal modes. Thus, especially for finding magnetic nano-systems which can be used as quaternary or even higher-order storage devices, it is rational to test several materials for the planned systems. Apparently, new materials may lead to novel and unexpected behaviour - and can thus result in novel functionalities.

Piezoelectricity and ferroelectricity of cellular polypropylene electrets films characterized by piezoresponse force microscopy

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

Miao, Hongchen; Sun, Yao; Zhou, Xilong

Cellular electrets polymer is a new ferroelectret material exhibiting large piezoelectricity and has attracted considerable attentions in researches and industries. Property characterization is very important for this material and current investigations are mostly on macroscopic properties. In this work, we conduct nanoscale piezoelectric and ferroelectric characterizations of cellular polypropylene (PP) films using piezoresponse force microscopy (PFM). First, both the single-frequency PFM and dual-frequency resonance-tracking PFM testings were conducted on the cellular PP film. The localized piezoelectric constant d{sub 33} is estimated to be 7–11pC/N by correcting the resonance magnification with quality factor and it is about one order lower thanmore » the macroscopic value. Next, using the switching spectroscopy PFM (SS-PFM), we studied polarization switching behavior of the cellular PP films. Results show that it exhibits the typical ferroelectric-like phase hysteresis loops and butterfly-shaped amplitude loops, which is similar to that of a poly(vinylidene fluoride) (PVDF) ferroelectric polymer film. However, both the phase and amplitude loops of the PP film are intensively asymmetric, which is thought to be caused by the nonzero remnant polarization after poling. Then, the D-E hysteresis loops of both the cellular PP film and PVDF film were measured by using the same wave form as that used in the SS-PFM, and the results show significant differences. Finally, we suggest that the ferroelectric-like behavior of cellular electrets films should be distinguished from that of typical ferroelectrics, both macroscopically and microscopically.« less

The Harvard Project Physics Film Program

ERIC Educational Resources Information Center

Bork, Alfred M.

1970-01-01

States the philosophy behind the Harvard Project Physics (HPP) film program. Describes the three long HPP films. Lists the 48 color film loops covering six broad topics, primarily motion and energy. The 8-mm silent loops are synchronized with the text materials. Explains some of the pedagogical possibilities of these film loops. (RR)

Stress-strain time-dependent behavior of A356.0 aluminum alloy subjected to cyclic thermal and mechanical loadings

NASA Astrophysics Data System (ADS)

Farrahi, G. H.; Ghodrati, M.; Azadi, M.; Rezvani Rad, M.

2014-08-01

This article presents the cyclic behavior of the A356.0 aluminum alloy under low-cycle fatigue (or isothermal) and thermo-mechanical fatigue loadings. Since the thermo-mechanical fatigue (TMF) test is time consuming and has high costs in comparison to low-cycle fatigue (LCF) tests, the purpose of this research is to use LCF test results to predict the TMF behavior of the material. A time-independent model, considering the combined nonlinear isotropic/kinematic hardening law, was used to predict the TMF behavior of the material. Material constants of this model were calibrated based on room-temperature and high-temperature low-cycle fatigue tests. The nonlinear isotropic/kinematic hardening law could accurately estimate the stress-strain hysteresis loop for the LCF condition; however, for the out-of-phase TMF, the condition could not predict properly the stress value due to the strain rate effect. Therefore, a two-layer visco-plastic model and also the Johnson-Cook law were applied to improve the estimation of the stress-strain hysteresis loop. Related finite element results based on the two-layer visco-plastic model demonstrated a good agreement with experimental TMF data of the A356.0 alloy.

Development of Passive Fuel Cell Thermal Management Technology

NASA Technical Reports Server (NTRS)

Burke, Kenneth A.; Jakupca, Ian; Colozza, Anthony

2011-01-01

The NASA Glenn Research Center is developing advanced passive thermal management technology to reduce the mass and improve the reliability of space fuel cell systems for the NASA exploration program. The passive thermal management system relies on heat conduction within the cooling plate to move the heat from the central portion of the cell stack out to the edges of the fuel cell stack rather than using a pumped loop cooling system to convectively remove the heat. Using the passive approach eliminates the need for a coolant pump and other cooling loop components which reduces fuel cell system mass and improves overall system reliability. Previous analysis had identified that low density, ultra-high thermal conductivity materials would be needed for the cooling plates in order to achieve the desired reductions in mass and the highly uniform thermal heat sink for each cell within a fuel cell stack. A pyrolytic graphite material was identified and fabricated into a thin plate using different methods. Also a development project with Thermacore, Inc. resulted in a planar heat pipe. Thermal conductivity tests were done using these materials. The results indicated that lightweight passive fuel cell cooling is feasible.

Experiments, Theory, and Simulation on the Evolution of Fabric in Granular Materials

DTIC Science & Technology

1992-07-27

Evolution of Fabric in Granular- Materials "I S ELECTE AU 27 199Z A 60 0 1C cb t H" Thi f, : :,ent h,- beo:n approved t f,:,z p, L~i- an-. .,!,’c d ...Hall 6.1102F Ithaca, New York 14853-1503 SPONSORING/MOYITORI G AGENCY NAME( S ) AND ADDRESS(ES) 10. SPONSORING/MONITORING LFOSR / / V . AGENCY REPORT...else loop j (1,jgp) xvel(l,j) = svel xvel(igp,j) = - s -vel end-loop end .if end ;--- analysis function --- def analyse d -vol = 0.0 loop i (1,izones

Approaches to flame resistant polymeric materials

NASA Technical Reports Server (NTRS)

Liepins, R.

1975-01-01

Four research and development areas are considered for further exploration in the quest of more flame-resistant polymeric materials. It is suggested that improvements in phenolphthalein polycarbonate processability may be gained through linear free energy relationship correlations. Looped functionality in the backbone of a polymer leads to both improved thermal resistance and increased solubility. The guidelines used in the pyrolytic carbon production constitute a good starting point for the development of improved flame-resistant materials. Numerous organic reactions requiring high temperatures and the techniques of protected functionality and latent functionality constitute the third area for exploration. Finally, some well-known organic reactions are suggested for the formation of polymers that were not made before.

Application Potential of Nanocrystalline Ribbons Still Pending

NASA Astrophysics Data System (ADS)

Butvin, Pavol; Butvinová, Beata; Švec, Peter; Sitek, Jozef

2010-09-01

Nanocrystalline soft-magnetic ribbons promised a wide-spread practical use when introduced at the beginning of nineties. After 20 years of extensive research there are still unclear material problems which are thought to be the principal reason why these materials show but marginal use. Poorly controllable magnetic anisotropy due to spontaneous intrinsic macroscopic stress that comes from an inevitable heterogeneity of the ribbon materials is pointed to in this work. Certain stress-based mechanisms are shown to induce the unintended anisotropy in the already familiar Finemets as well as in the newer Hitperms. Hysteresis loops, domain structure and power loss is used to reveal the anisotropy consequences and particular connected but still unanswered questions are pinpointed.

Inverse spin Hall effect in a closed loop circuit

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

Omori, Y.; Auvray, F.; Wakamura, T.

We present measurements of inverse spin Hall effects (ISHEs), in which the conversion of a spin current into a charge current via the ISHE is detected not as a voltage in a standard open circuit but directly as the charge current generated in a closed loop. The method is applied to the ISHEs of Bi-doped Cu and Pt. The derived expression of ISHE for the loop structure can relate the charge current flowing into the loop to the spin Hall angle of the SHE material and the resistance of the loop.

Insights from Placing Photosynthetic Light Harvesting into Context.

PubMed

Demmig-Adams, Barbara; Stewart, Jared J; Burch, Tyson A; Adams, William W

2014-08-21

Solar-energy conversion through natural photosynthesis forms the base of virtually all food chains on Earth and provides fiber, materials, and fuels, as well as inspiration for the design of biomimetic energy-conversion systems. We summarize well-known as well as recently discovered feedback loops between natural light-harvesting systems and whole-organism function in natural settings. We propose that the low effective quantum yield of natural light-harvesting systems in high light is caused by downstream limitations rather than unavoidable intrinsic vulnerabilities. We evaluate potential avenues, and their costs and benefits, for increasing the maximal rate and photon yield of photosynthesis in high light in plants and photosynthetic microbes. By summarizing mechanisms observable only in complex systems (whole plants, algae, or, in some cases, intact leaves), we aim to stimulate future research efforts on reciprocal feedback loops between light harvesting and downstream processes in whole organisms and to provide additional arguments for the significance of research on photosynthetic light harvesting.

Soft Robotics: from scientific challenges to technological applications

NASA Astrophysics Data System (ADS)

Laschi, C.

2016-05-01

Soft robotics is a recent and rapidly growing field of research, which aims at unveiling the principles for building robots that include soft materials and compliance in the interaction with the environment, so as to exploit so-called embodied intelligence and negotiate natural environment more effectively. Using soft materials for building robots poses new technological challenges: the technologies for actuating soft materials, for embedding sensors into soft robot parts, for controlling soft robots are among the main ones. This is stimulating research in many disciplines and many countries, such that a wide community is gathering around initiatives like the IEEE TAS TC on Soft Robotics and the RoboSoft CA - A Coordination Action for Soft Robotics, funded by the European Commission. Though still in its early stages of development, soft robotics is finding its way in a variety of applications, where safe contact is a main issue, in the biomedical field, as well as in exploration tasks and in the manufacturing industry. And though the development of the enabling technologies is still a priority, a fruitful loop is growing between basic research and application-oriented research in soft robotics.

Unmixing Magnetic Hysteresis Loops

NASA Astrophysics Data System (ADS)

Heslop, D.; Roberts, A. P.

2012-04-01

Magnetic hysteresis loops provide important information in rock and environmental magnetic studies. Natural samples often contain an assemblage of magnetic particles composed of components with different origins. Each component potentially carries important environmental information. Hysteresis loops, however, provide information concerning the bulk magnetic assemblage, which makes it difficult to isolate the specific contributions from different sources. For complex mineral assemblages an unmixing strategy with which to separate hysteresis loops into their component parts is therefore essential. Previous methods to unmix hysteresis data have aimed at separating individual loops into their constituent parts using libraries of type-curves thought to correspond to specific mineral types. We demonstrate an alternative approach, which rather than decomposing a single loop into monomineralic contributions, examines a collection of loops to determine their constituent source materials. These source materials may themselves be mineral mixtures, but they provide a genetically meaningful decomposition of a magnetic assemblage in terms of the processes that controlled its formation. We show how an empirically derived hysteresis mixing space can be created, without resorting to type-curves, based on the co-variation within a collection of measured loops. Physically realistic end-members, which respect the expected behaviour and symmetries of hysteresis loops, can then be extracted from the mixing space. These end-members allow the measured loops to be described as a combination of invariant parts that are assumed to represent the different sources in the mixing model. Particular attention is paid to model selection and estimating the complexity of the mixing model, specifically, how many end-members should be included. We demonstrate application of this approach using lake sediments from Butte Valley, northern California. Our method successfully separates the hysteresis loops into sources with a variety of terrigenous and authigenic origins.

Behaviour of F82H mod. stainless steel in lead-bismuth under temperature gradient

NASA Astrophysics Data System (ADS)

Gómez Briceño, D.; Martín Muñoz, F. J.; Soler Crespo, L.; Esteban, F.; Torres, C.

2001-07-01

Austenitic steels can be used in a hybrid system in contact with liquid lead-bismuth eutectic if the region of operating temperatures is not beyond 400°C. For higher temperatures, martensitic steels are recommended. However, at long times, the interaction between the structural material and the eutectic leads to the dissolution of some elements of the steel (Ni, Cr and Fe, mainly) in the liquid metal. In a non-isothermal lead-bismuth loop, the material dissolution takes place at the hot leg of the circuit and, due to the mass transfer, deposition occurs at the cold leg. One of the possible ways to improve the performance of structural materials in lead-bismuth is the creation of an oxide layer. Tests have been performed in a small natural convection loop built of austenitic steel (316L) that has been operating for 3000 h. This loop contains a test area in which several samples of F82Hmod. martensitic steel have been tested at different times. A gas with an oxygen content of 10 ppm was bubbled in the hot area of the circuit during the operation time. The obtained results show that an oxide layer is formed on the samples introduced in the loop at the beginning of the operation and this layer increases with time. However, the samples introduced at different times during the loop operation, are not protected by oxide layers and present material dissolution in some cases.

Active Knits for Radical Change Air Force Structures

DTIC Science & Technology

2012-10-01

for self - healing structures, but the material distribution could be optimized to achieve desired mechanical properties or obtain a predetermined...causes the material to transition from the soft martensite phase to the stiff austenite phase. When heated the loops attempt to return to their...nominally straight, is bent into the loop shape when in the cold, relatively soft martensite state. When heated to the relatively stiff austenite

Heterogeneous dislocation loop formation near grain boundaries in a neutron-irradiated commercial FeCrAl alloy

DOE PAGES

Field, Kevin G.; Briggs, Samuel A.; Hu, Xunxiang; ...

2016-11-01

FeCrAl alloys are an attractive materials class for nuclear power applications due to their increased environmental compatibility over more traditional nuclear materials. Preliminary studies into the radiation tolerance of FeCrAl alloys under accelerated neutron testing between 300-400 °C have shown post-irradiation microstructures containing dislocation loops and Cr-rich ' phase. Although these initial works established the post-irradiation microstructures, little to no focus was applied towards the influence of pre-irradiation microstructures on this response. Here, a well annealed commercial FeCrAl alloy, Alkrothal 720, was neutron irradiated to 1.8 dpa at 382 °C and then the role of random high angle grain boundariesmore » on the spatial distribution and size of dislocation loops, dislocation loops, and black dot damage was analyzed using on-zone scanning transmission electron microscopy. Results showed a clear heterogeneous dislocation loop formation with dislocation loops showing an increased number density and size, black dot damage showing a significant number density decrease, and an increased size of dislocation loops in the vicinity directly adjacent to the grain boundary. Lastly, these results suggest the importance of the pre-irradiation microstructure on the radiation tolerance of FeCrAl alloys.« less

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

Calabrese, G.; Capineri, L., E-mail: lorenzo.capineri@unifi.it; Granato, M.

This paper describes the design of a system for the characterization of magnetic hysteresis behavior in soft ferrite magnetic cores. The proposed setup can test magnetic materials exciting them with controlled arbitrary magnetic field waveforms, including the capability of providing a DC bias, in a frequency bandwidth up to 500 kHz, with voltages up to 32 V peak-to-peak, and currents up to 10 A peak-to-peak. In order to have an accurate control of the magnetic field waveform, the system is based on a voltage controlled current source. The electronic design is described focusing on closed loop feedback stabilization and passivemore » components choice. The system has real-time hysteretic loop acquisition and visualization. The comparisons between measured hysteresis loops of sample magnetic materials and datasheet available ones are shown. Results showing frequency and thermal behavior of the hysteresis of a test sample prove the system capabilities. Moreover, the B-H loops obtained with a multiple waveforms excitation signal, including DC bias, are reported. The proposal is a low-cost and replicable solution for hysteresis characterization of magnetic materials used in power electronics.« less

Research on phase locked loop in optical memory servo system

NASA Astrophysics Data System (ADS)

Qin, Liqin; Ma, Jianshe; Zhang, Jianyong; Pan, Longfa; Deng, Ming

2005-09-01

Phase locked loop (PLL) is a closed loop automatic control system, which can track the phase of input signal. It widely applies in each area of electronic technology. This paper research the phase locked loop in optical memory servo area. This paper introduces the configuration of digital phase locked loop (PLL) and phase locked servo system, the control theory, and analyses system's stability. It constructs the phase locked loop experiment system of optical disk spindle servo, which based on special chip. DC motor is main object, this system adopted phase locked servo technique and digital signal processor (DSP) to achieve constant linear velocity (CLV) in controlling optical spindle motor. This paper analyses the factors that affect the stability of phase locked loop in spindle servo system, and discusses the affection to the optical disk readout signal and jitter due to the stability of phase locked loop.

Acoustic velocity measurements in materials using a regenerative method

DOEpatents

Laine, Edwin F.

1986-01-01

Acoustic energy is propagated through earth material between an electro-acoustic generator and a receiver which converts the received acoustic energy into electrical signals. A closed loop is formed by a variable gain amplifier system connected between the receiver and the generator. The gain of the amplifier system is increased until sustained oscillations are produced in the closed loop. The frequency of the oscillations is measured as an indication of the acoustic propagation velocity through the earth material. The amplifier gain is measured as an indication of the acoustic attenuation through the earth materials. The method is also applicable to the non-destructive testing of structural materials, such as steel, aluminum and concrete.

Acoustic-velocity measurements in materials using a regenerative method

DOEpatents

Laine, E.F.

1982-09-30

Acoustic energy is propatated through earth material between an electro-acoustic generator and a receiver which converts the received acoustic energy into electrical signals. A closed loop is formed by a variable gain amplifier system connected between the receiver and the generator. The gain of the amplifier system is increased until sustained oscillations are produced in the closed loop. The frequency of the oscillations is measured as an indication of the acoustic propagation velocity through the earth material. The amplifier gain is measured as an indication of the acoustic attenuation through the earth materials. The method is also applicable to the non-destructive testing of structural materials, such as steel, aluminum and concrete.

Polymeric heat pipe wick

NASA Technical Reports Server (NTRS)

Seidenberg, Benjamin

1988-01-01

A wick for use in a capillary loop pump heat pipe is described. The wick material is an essentially uniformly porous, permeable, open-cell, polyethylene thermoplastic foam having an ultrahigh average molecular weight of from approximately 1 to 5 million, and an average pore size of about 10 to 12 microns. A representative material having these characteristics is POREX UF, which has an average molecular weight of about 3 million. This material is fully compatible with the FREONs and anhydrous ammonia and allows for the use of these very efficient working fluids in capillary loops.

Analytical and experimental investigation of flutter suppression by piezoelectric actuation

NASA Technical Reports Server (NTRS)

Heeg, Jennifer

1993-01-01

The objective of this research was to analytically and experimentally study the capabilities of piezoelectric plate actuators for suppressing flutter. Piezoelectric materials are characterized by their ability to produce voltage when subjected to a mechanical strain. The converse piezoelectric effect can be utilized to actuate a structure by applying a voltage. For this investigation, a two-degree-of-freedom wind tunnel model was designed, analyzed, and tested. The model consisted of a rigid wing and a flexible mount system that permitted a translational and a rotational degree of freedom. The model was designed such that flutter was encountered within the testing envelope of the wind tunnel. Actuators made of piezoelectric material were affixed to leaf springs of the mount system. Command signals, applied to the piezoelectric actuators, exerted control over the damping and stiffness properties. A mathematical aeroservoelastic model was constructed by using finite element methods, laminated plate theory, and aeroelastic analysis tools. Plant characteristics were determined from this model and verified by open loop experimental tests. A flutter suppression control law was designed and implemented on a digital control computer. Closed loop flutter testing was conducted. The experimental results represent the first time that adaptive materials have been used to actively suppress flutter. They demonstrate that small, carefully placed actuating plates can be used effectively to control aeroelastic response.

Magnetic and Electrical Characteristics of Permalloy Thin Tape Bobbin Cores

NASA Technical Reports Server (NTRS)

Schwarze, Gene E.; Wieserman, William R.; Niedra, Janis M.

2005-01-01

The core loss, that is, the power loss, of a soft ferromagnetic material is a function of the flux density, frequency, temperature, excitation type (voltage or current), excitation waveform (sine, square, etc.) and lamination or tape thickness. In previously published papers we have reported on the specific core loss and dynamic B-H loop results for several polycrystalline, nanocrystalline, and amorphous soft magnetic materials. In this previous research we investigated the effect of flux density, frequency, temperature, and excitation waveform for voltage excitation on the specific core loss and dynamic B-H loop. In this paper, we will report on an experimental study to investigate the effect of tape thicknesses of 1, 1/2, 1/4, and 1/8-mil Permalloy type magnetic materials on the specific core loss. The test cores were fabricated by winding the thin tapes on ceramic bobbin cores. The specific core loss tests were conducted at room temperature and over the frequency range of 10 kHz to 750 kHz using sine wave voltage excitation. The results of this experimental investigation will be presented primarily in graphical form to show the effect of tape thickness, frequency, and magnetic flux density on the specific core loss. Also, the experimental results when applied to power transformer design will be briefly discussed.

Research on the man in the loop control system of the robot arm based on gesture control

NASA Astrophysics Data System (ADS)

Xiao, Lifeng; Peng, Jinbao

2017-03-01

The Man in the loop control system of the robot arm based on gesture control research complex real-world environment, which requires the operator to continuously control and adjust the remote manipulator, as the background, completes the specific mission human in the loop entire system as the research object. This paper puts forward a kind of robot arm control system of Man in the loop based on gesture control, by robot arm control system based on gesture control and Virtual reality scene feedback to enhance immersion and integration of operator, to make operator really become a part of the whole control loop. This paper expounds how to construct a man in the loop control system of the robot arm based on gesture control. The system is a complex system of human computer cooperative control, but also people in the loop control problem areas. The new system solves the problems that the traditional method has no immersion feeling and the operation lever is unnatural, the adjustment time is long, and the data glove mode wears uncomfortable and the price is expensive.

Thermal management systems and methods

DOEpatents

Gering, Kevin L.; Haefner, Daryl R.

2006-12-12

A thermal management system for a vehicle includes a heat exchanger having a thermal energy storage material provided therein, a first coolant loop thermally coupled to an electrochemical storage device located within the first coolant loop and to the heat exchanger, and a second coolant loop thermally coupled to the heat exchanger. The first and second coolant loops are configured to carry distinct thermal energy transfer media. The thermal management system also includes an interface configured to facilitate transfer of heat generated by an internal combustion engine to the heat exchanger via the second coolant loop in order to selectively deliver the heat to the electrochemical storage device. Thermal management methods are also provided.

Heterogeneous dislocation loop formation near grain boundaries in a neutron-irradiated commercial FeCrAl alloy

NASA Astrophysics Data System (ADS)

Field, Kevin G.; Briggs, Samuel A.; Hu, Xunxiang; Yamamoto, Yukinori; Howard, Richard H.; Sridharan, Kumar

2017-01-01

FeCrAl alloys are an attractive class of materials for nuclear power applications because of their increased environmental compatibility compared with more traditional nuclear materials. Preliminary studies into the radiation tolerance of FeCrAl alloys under accelerated neutron testing between 300 and 400 °C have shown post-irradiation microstructures containing dislocation loops and a Cr-rich α‧ phase. Although these initial studies established the post-irradiation microstructures, there was little to no focus on understanding the influence of pre-irradiation microstructures on this response. In this study, a well-annealed commercial FeCrAl alloy, Alkrothal 720, was neutron irradiated to 1.8 displacements per atom (dpa) at 382 °C and then the effect of random high-angle grain boundaries on the spatial distribution and size of a〈100〉 dislocation loops, a/2〈111〉 dislocation loops, and black dot damage was analyzed using on-zone scanning transmission electron microscopy. Results showed a clear heterogeneous dislocation loop formation with a/2〈111〉 dislocation loops showing an increased number density and size, black dot damage showing a significant number density decrease, and a〈100〉 dislocation loops exhibiting an increased size in the vicinity of the grain boundary. These results suggest the importance of the pre-irradiation microstructure and, specifically, defect sink density spacing to the radiation tolerance of FeCrAl alloys.

Relationships between Perron-Frobenius eigenvalue and measurements of loops in networks

NASA Astrophysics Data System (ADS)

Chen, Lei; Kou, Yingxin; Li, Zhanwu; Xu, An; Chang, Yizhe

2018-07-01

The Perron-Frobenius eigenvalue (PFE) is widely used as measurement of the number of loops in networks, but what exactly the relationship between the PFE and the number of loops in networks is has not been researched yet, is it strictly monotonically increasing? And what are the relationships between the PFE and other measurements of loops in networks? Such as the average loop degree of nodes, and the distribution of loop ranks. We make researches on these questions based on samples of ER random network, NW small-world network and BA scale-free network, and the results confirm that, both the number of loops in network and the average loop degree of nodes of all samples do increase with the increase of the PFE in general trend, but neither of them are strictly monotonically increasing, so the PFE is capable to be used as a rough estimative measurement of the number of loops in networks and the average loop degree of nodes. Furthermore, we find that a majority of the loop ranks of all samples obey Weibull distribution, of which the scale parameter A and the shape parameter B have approximate power-law relationships with the PFE of the samples.

PRESENT CONDITION OF FOOD WASTE RECYCLING LOOP BASED ON RECYCLING PROJECT CERTIFICATION OF THE FOOD WASTE RECYCLING LAW

NASA Astrophysics Data System (ADS)

Kita, Tomoko; Kanaya, Ken

Purpose of this research is to clear present condition of food waste recycling loops based on recycling project certification of the Food Waste Recycling Law. Method of this research is questionnaire survey to companies constituting the loops. Findings of this research are as follows: 1. Proponents of the loop is most often the recycling companies. 2. Food waste recycling rate is 61% for the food retailing industry and 81% for the food service industry. These values are higher than the national average in 2006. The effect of the revision of recycling project certification is suggested.

Damage-tolerant nanotwinned metals with nanovoids under radiation environments

PubMed Central

Chen, Y.; Yu, K Y.; Liu, Y.; Shao, S.; Wang, H.; Kirk, M. A.; Wang, J.; Zhang, X.

2015-01-01

Material performance in extreme radiation environments is central to the design of future nuclear reactors. Radiation induces significant damage in the form of dislocation loops and voids in irradiated materials, and continuous radiation often leads to void growth and subsequent void swelling in metals with low stacking fault energy. Here we show that by using in situ heavy ion irradiation in a transmission electron microscope, pre-introduced nanovoids in nanotwinned Cu efficiently absorb radiation-induced defects accompanied by gradual elimination of nanovoids, enhancing radiation tolerance of Cu. In situ studies and atomistic simulations reveal that such remarkable self-healing capability stems from high density of coherent and incoherent twin boundaries that rapidly capture and transport point defects and dislocation loops to nanovoids, which act as storage bins for interstitial loops. This study describes a counterintuitive yet significant concept: deliberate introduction of nanovoids in conjunction with nanotwins enables unprecedented damage tolerance in metallic materials. PMID:25906997

Damage-tolerant nanotwinned metals with nanovoids under radiation environments.

PubMed

Chen, Y; Yu, K Y; Liu, Y; Shao, S; Wang, H; Kirk, M A; Wang, J; Zhang, X

2015-04-24

Material performance in extreme radiation environments is central to the design of future nuclear reactors. Radiation induces significant damage in the form of dislocation loops and voids in irradiated materials, and continuous radiation often leads to void growth and subsequent void swelling in metals with low stacking fault energy. Here we show that by using in situ heavy ion irradiation in a transmission electron microscope, pre-introduced nanovoids in nanotwinned Cu efficiently absorb radiation-induced defects accompanied by gradual elimination of nanovoids, enhancing radiation tolerance of Cu. In situ studies and atomistic simulations reveal that such remarkable self-healing capability stems from high density of coherent and incoherent twin boundaries that rapidly capture and transport point defects and dislocation loops to nanovoids, which act as storage bins for interstitial loops. This study describes a counterintuitive yet significant concept: deliberate introduction of nanovoids in conjunction with nanotwins enables unprecedented damage tolerance in metallic materials.

Damage-tolerant nanotwinned metals with nanovoids under radiation environments

DOE PAGES

Chen, Y.; Yu, K. Y.; Liu, Y.; ...

2015-04-24

Material performance in extreme radiation environments is central to the design of future nuclear reactors. Radiation induces significant damage in the form of dislocation loops and voids in irradiated materials, and continuous radiation often leads to void growth and subsequent void swelling in metals with low stacking fault energy. Here we show that by using in situ heavy ion irradiation in a transmission electron microscope, pre-introduced nanovoids in nanotwinned Cu efficiently absorb radiation-induced defects accompanied by gradual elimination of nanovoids, enhancing radiation tolerance of Cu. In situ studies and atomistic simulations reveal that such remarkable self-healing capability stems from highmore » density of coherent and incoherent twin boundaries that rapidly capture and transport point defects and dislocation loops to nanovoids, which act as storage bins for interstitial loops. This study describes a counterintuitive yet significant concept: deliberate introduction of nanovoids in conjunction with nanotwins enables unprecedented damage tolerance in metallic materials.« less

Versatile retraction mechanics: Implant assisted en-masse retraction with a boot loop.

PubMed

Philip, Pramod; Jose, Nidhin Philip

2015-03-01

The purpose of this paper is to explain the versatility offered by the use of arch wires with boot loops in retraction mechanics while taking direct anchorage from mini-screws. The materials include the mini screws placed at the appropriate location and retraction arches made of 0.019 X 0.025 SS with boot loops placed distal to the lateral incisors. Mini screw provides a stable anchorage for enmasse retraction of the anterior teeth with the help of a boot loop using sliding and/or loop mechanics. The arch wires with boot loops have a definite advantage over the soldered/crimpable hooks because of the versatility it offers during the process of retraction. An innovative approach combining the advantages of absolute anchorage using mini implants and a retraction arch with boot loop is presented here.

Heat Pipes and Heat Rejection Component Testing at NASA Glenn Research Center

NASA Technical Reports Server (NTRS)

Sanzi, James L.; Jaworske, Donald A.

2012-01-01

Titanium-water heat pipes are being evaluated for use in the heat rejection system for space fission power systems. The heat rejection syst em currently comprises heat pipes with a graphite saddle and a composite fin. The heat input is a pumped water loop from the cooling of the power conversion system. The National Aeronautics and Space Administration has been life testing titanium-water heat pipes as well as eval uating several heat pipe radiator designs. The testing includes thermal modeling and verification of model, material compatibility, frozen startup of heat pipe radiators, and simulating low-gravity environments. Future thermal testing of titanium-water heat pipes includes low-g ravity testing of thermosyphons, radiation testing of heat pipes and fin materials, water pump performance testing, as well as Small Busine ss Innovation Research funded deliverable prototype radiator panels.

Tunable Composite Metamaterials with Imbedded Coherently Controllable Atomic or Molecular Materials

DTIC Science & Technology

2010-10-07

using nanoporous alumina templates [G. Sauer, G. Brehm, and S. Schneider, “Highly ordered monocrystalline silver nanowire arrays” J. Appl...using stimulated Raman Scattering into the Stokes modes. Fig. 2: Left panel : A cross-sectional view of a typical unit cell of the plasmonic loop...Right panel : Magnetic response of an isolated loop inclusion illustrating the concentration of the magnetic field inside the loop at resonance, when

Diagnostics of electron-heated solar flare models. III - Effects of tapered loop geometry and preheating

NASA Technical Reports Server (NTRS)

Emslie, A. G.; Li, Peng; Mariska, John T.

1992-01-01

A series of hydrodynamic numerical simulations of nonthermal electron-heated solar flare atmospheres and their corresponding soft X-ray Ca XIX emission-line profiles, under the conditions of tapered flare loop geometry and/or a preheated atmosphere, is presented. The degree of tapering is parameterized by the magnetic mirror ratio, while the preheated atmosphere is parameterized by the initial upper chromospheric pressure. In a tapered flare loop, it is found that the upward motion of evaporated material is faster compared with the case where the flare loop is uniform. This is due to the diverging nozzle seen by the upflowing material. In the case where the flare atmosphere is preheated and the flare geometry is uniform, the response of the atmosphere to the electron collisional heating is slow. The upward velocity of the hydrodynamic gas is reduced due not only to the large coronal column depth, but also to the increased inertia of the overlying material. It is concluded that the only possible electron-heated scenario in which the predicted Ca XIX line profiles agree with the BCS observations is when the impulsive flare starts in a preheated dense corona.

Ceramic heat pipe wick

NASA Technical Reports Server (NTRS)

Seidenberg, Benjamin (Inventor); Swanson, Theodore (Inventor)

1989-01-01

A wick for use in a capillary loop pump heat pipe is disclosed. The wick material is an essentially uniformly porous, permeable, open-cell, silicon dioxide/aluminum oxide inorganic ceramic foam having a silica fiber ratio, by weight, of about 78 to 22, respectively, a density of 6 lbs/cu ft, and an average pore size of less than 5 microns. A representative material having these characteristics is Lockheed Missile and Space Company, Inc.'s HTP 6-22. This material is fully compatible with the freons and anhydrous ammonia and allows for the use of these very efficient working fluids, and others, in capillary loops.

Skylab

NASA Image and Video Library

1973-01-01

Breaking the grip of the closed magnetic loops that constrain other gases around it, a spray of chromospheric material surges upward, free of the Sun. Views 1 through 5 were recorded about 5 minutes apart by Skylab and comprise a composite of separate images made in chromospheric (red), transition region (green), and coronal (blue) temperatures of an ultraviolet sequence that depicts a solar eruption. Eruption begins (view 2) as material in or near a small, compact loop develops enough energy to overcome the Sun's magnetic bonds.

A Unified Approach for Modeling Inelastic Behavior of Structural Metals under Complex Cyclic Loadings.

DTIC Science & Technology

1977-05-01

this report are not to be used for advertising , publication, or promotional purposes. Citat ion of trade names does not constitute an off icial... Vs . Real Materials 3 PLASTIC HYSTERESIS PHENOMENA 12 Observed Transient Phenomena Analysis of Hysteresis Loops Observed Typical Yie ld Range...strain or stress amp litude). Fitr examp le , if varm m uus sited hyshet esis loops produced by the model a me super- Memory Modei Vs . Real Materials

Methods of forming thermal management systems and thermal management methods

DOEpatents

Gering, Kevin L.; Haefner, Daryl R.

2012-06-05

A thermal management system for a vehicle includes a heat exchanger having a thermal energy storage material provided therein, a first coolant loop thermally coupled to an electrochemical storage device located within the first coolant loop and to the heat exchanger, and a second coolant loop thermally coupled to the heat exchanger. The first and second coolant loops are configured to carry distinct thermal energy transfer media. The thermal management system also includes an interface configured to facilitate transfer of heat generated by an internal combustion engine to the heat exchanger via the second coolant loop in order to selectively deliver the heat to the electrochemical storage device. Thermal management methods are also provided.

a Multi Objective Model for Optimization of a Green Supply Chain Network

NASA Astrophysics Data System (ADS)

Paksoy, Turan; Özceylan, Eren; Weber, Gerhard-Wilhelm

2010-06-01

This study develops a model of a closed-loop supply chain (CLSC) network which starts with the suppliers and recycles with the decomposition centers. As a traditional network design, we consider minimizing the all transportation costs and the raw material purchasing costs. To pay attention for the green impacts, different transportation choices are presented between echelons according to their CO2 emissions. The plants can purchase different raw materials in respect of their recyclable ratios. The focuses of this paper are conducting the minimizing total CO2 emissions. Also we try to encourage the customers to use recyclable materials as an environmental performance viewpoint besides minimizing total costs. A multi objective linear programming model is developed via presenting a numerical example. We close the paper with recommendations for future researches.

Estimation of changes in insulation resistance with various design parameters of interdigitated wire loops.

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

Cordaro, Joseph Gabriel; Jones, Reese E.; Neel, Wiley Christopher

2015-09-01

In this report we explore the sensitivities of the insulation resistance between two loops of wire embedded in insulating materials with a simple, approximate model. We discuss limita- tions of the model and ideas for improvements.

FY 2017-Progress Report on the Design and Construction of the Sodium Loop SMT-3

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

Natesan, K.; Momozaki, Y.

This report provides an update on the design of a forced-convection sodium loop to be used for the evaluation of sodium compatibility of advanced Alloy 709 with emphasis on long term exposures of tensile, creep, fatigue, creep fatigue, and fracture toughness ASTM-size specimens in support of ASME Code qualification and NRC licensing. The report is a deliverable (Level 4) in FY17 (M4AT-17AN1602094), under the Work Package AT-17AN160209, “Sodium Compatibility” performed by Argonne National Laboratory (ANL), as part of the Advanced Materials Program for the Advanced Reactor Technology. This work package enables the development of advanced structural materials by providing corrosion,more » microstructure, and mechanical property data from the standpoint of sodium compatibility of advanced structural alloys. The first sodium loop (SMT-1) with a single tank was constructed in 2011 at ANL and has been in operation for exposure of subsize sheet specimens of advanced alloys at a single temperature. The second sodium loop with dual tanks (SMT-2) was constructed in 2013 and has been in operation for the exposure of subsize sheet specimens of advanced alloys at two different temperatures. The current loop (SMT-3) has been designed to incorporate sufficient chamber capacity to expose a large number of ASTM-size specimens to evaluate the sodium effects on tensile, creep, fatigue, creep-fatigue, and fracture toughness properties, in support of ASME Code Qualification and USNRC Licensing. The design of individual components for the third sodium loop SMT-3 is almost complete. The design also has been sent to an outside vendor for piping analysis to be in compliance with ASME Code. A purchase order has been placed with an outside vendor for the fabrication of major components such as the specimen exposure tanks. However, we have contracted with another vendor to establish the piping design in compliance with ASME design codes. The piping design was completed in FY2017 and the information is being transmitted to the tank fabricator. The SMT-3 loop will be located in Building 206 adjacent to the currently operating SMT-2 loop. In addition, we have demolished the aged power supply system in Building 206 and installed a new transformer, wiring, and power panels for the new loop. Procurement of some of the long lead items such as valves, EM pumps, EM flowmeters, etc. is in progress and will continue in FY 2018. The construction of components such as cold trap, economizers, piping arrangement etc. will be performed in the central shops at ANL. About 150 liters of sodium for the loop will be procured in early FY2018. The loop system is designed to circulate sodium through the sample tanks and the associated loop without an operator for an extended period of time. With the three sodium loops (with single-tank, dual-tank and four–tanks), materials can be tested at different sodium temperatures, and large tensile, creep, fatigue, creep-fatigue, and fracture toughness specimens can be exposed to sodium for extended periods of time and generate data on mechanical properties in support of ASME Code Qualification and USNRC Licensing of advanced Alloy 709 for use as a structural material in SFRs.« less

Experimental Investigation of DC-Bias Related Core Losses in a Boost Inductor (Postprint)

DTIC Science & Technology

2014-08-01

dc bias-flux conditions. These dc bias conditions result in distorted hysteresis loops , increased core losses, and have been shown to be independent...These dc bias conditions result in dis- torted hysteresis loops , increased core losses, and have been shown to be independent of core material. The...controllable converter load currents, this topology is ideal to study dc-related losses. Inductor core hysteresis loop characterization was accomplished

IN-PILE CORROSION TEST LOOPS FOR AQUEOUS HOMOGENEOUS REACTOR SOLUTIONS

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

Savage, H.C.; Jenks, G.H.; Bohlmann, E.G.

1960-12-21

An in-pile corrosion test loop is described which is used to study the effect of reactor radiation on the corrosion of materials of construction and the chemical stability of fuel solutions of interest to the Aqueous Homogeneous Reactor Program at ORNL. Aqueous solutions of uranyl sulfate are circulated in the loop by means of a 5-gpm canned-rotor pump, and the pump loop is designed for operation at temperatures to 300 ts C and pressures to 2000 psia while exposed to reactor radiation in beam-hole facilities of the LITR and ORR. Operation of the first loop in-pile was begun in Octobermore » 1954, and since that time 17 other in-pile loop experiments were completed. Design criteria of the pump loop and its associated auxiliary equipment and instrumentation are described. In-pile operating procedures, safety features, and operating experience are presented. A cost summary of the design, fabrication, and installation of the loop and experimental facillties is also included. (auth)« less

Structural materials challenges for advanced reactor systems

NASA Astrophysics Data System (ADS)

Yvon, P.; Carré, F.

2009-03-01

Key technologies for advanced nuclear systems encompass high temperature structural materials, fast neutron resistant core materials, and specific reactor and power conversion technologies (intermediate heat exchanger, turbo-machinery, high temperature electrolytic or thermo-chemical water splitting processes, etc.). The main requirements for the materials to be used in these reactor systems are dimensional stability under irradiation, whether under stress (irradiation creep or relaxation) or without stress (swelling, growth), an acceptable evolution under ageing of the mechanical properties (tensile strength, ductility, creep resistance, fracture toughness, resilience) and a good behavior in corrosive environments (reactor coolant or process fluid). Other criteria for the materials are their cost to fabricate and to assemble, and their composition could be optimized in order for instance to present low-activation (or rapid desactivation) features which facilitate maintenance and disposal. These requirements have to be met under normal operating conditions, as well as in incidental and accidental conditions. These challenging requirements imply that in most cases, the use of conventional nuclear materials is excluded, even after optimization and a new range of materials has to be developed and qualified for nuclear use. This paper gives a brief overview of various materials that are essential to establish advanced systems feasibility and performance for in pile and out of pile applications, such as ferritic/martensitic steels (9-12% Cr), nickel based alloys (Haynes 230, Inconel 617, etc.), oxide dispersion strengthened ferritic/martensitic steels, and ceramics (SiC, TiC, etc.). This article gives also an insight into the various natures of R&D needed on advanced materials, including fundamental research to investigate basic physical and chemical phenomena occurring in normal and accidental operating conditions, lab-scale tests to characterize candidate materials mechanical properties and corrosion resistance, as well as component mock-up tests on technology loops to validate potential applications while accounting for mechanical design rules and manufacturing processes. The selection, assessment and validation of materials necessitate a large number of experiments, involving rare and expensive facilities such as research reactors, hot laboratories or corrosion loops. The modelling and the codification of the behaviour of materials will always involve the use of such technological experiments, but it is of utmost importance to develop also a predictive material science. Finally, the paper stresses the benefit of prospects of multilateral collaboration to join skills and share efforts of R&D to achieve in the nuclear field breakthroughs on materials that have already been achieved over the past decades in other industry sectors (aeronautics, metallurgy, chemistry, etc.).

Comparison of cervical dysplasia treatment with leep-loop method and CO2 laser vaporization

NASA Astrophysics Data System (ADS)

Wozniak, Jakub; Rzymski, Pawel; Opala, Tomasz; Wilczak, Maciej; Sajdak, Stefan

2003-10-01

There are several methods of treating cervical dysplasia, including surgical and electric conisation, laservaporisation. The aim of our study was to evaluate leep-loop method and laservaporisation wtih CO2 laser. Material consisted of 49 women, 28 underwent leep-loop conisation and 21 lavervaporisation. The effectiveness of laser treatment was 90,4% and with leep-loop 96,4%, but the difference was not statistically significant. Mean time of wound healing and frequency of pain was shorter after laser treatment, but the differences were not statistically significant. Conclusions: Effect treatment with both methods is comparable.

Overview of Research Transition Products

NASA Technical Reports Server (NTRS)

Robinson, John

2014-01-01

Demonstrate increased, more consistent use of Performance- Based Navigation (PBN). Accelerate transfer of NASA scheduling and spacing technologies for inclusion in late mid-term NAS. During high-fidelity human-in-the-loop simulations of Terminal Sequencing and Spacing, air traffic controllers have significantly improved their use of PBN procedures during busy traffic periods without increased workload. Executed an aggressive, short timeframe development schedule. Developed TSS prototype based upon FAA operational systems. Conducted multiple joint FAA/NASA human-in-the-loop simulations. Performed repeated incremental deliveries of tech transfer material to non-traditional RTT stakeholders. Will continue to participate in later phases of FAA acquisition process. ATD-1 transferred Terminal Sequencing and Spacing (TSS) technologies to the FAA. TSS enables routine use of underutilized advanced avionics and PBN procedures. Potential benefits to airlines operating at initial TSS sites estimated to be $300-400M/year. FAA is planning for an initial capability in the NAS in 2018.

Low Pressure Seeder Development for PIV in Large Scale Open Loop Wind Tunnels

NASA Astrophysics Data System (ADS)

Schmit, Ryan

2010-11-01

A low pressure seeding techniques have been developed for Particle Image Velocimetry (PIV) in large scale wind tunnel facilities was performed at the Subsonic Aerodynamic Research Laboratory (SARL) facility at Wright-Patterson Air Force Base. The SARL facility is an open loop tunnel with a 7 by 10 foot octagonal test section that has 56% optical access and the Mach number varies from 0.2 to 0.5. A low pressure seeder sprayer was designed and tested in the inlet of the wind tunnel. The seeder sprayer was designed to produce an even and uniform distribution of seed while reducing the seeders influence in the test section. ViCount Compact 5000 using Smoke Oil 180 was using as the seeding material. The results show that this low pressure seeder does produce streaky seeding but excellent PIV images are produced.

Stimuli sensitive polymers and self regulated drug delivery systems: a very partial review.

PubMed

Siegel, Ronald A

2014-09-28

Since the early days of the Journal of Controlled Release, there has been considerable interest in materials that can release drug on an "on-demand" basis. So called "stimuli-responsive" and "intelligent" systems have been designed to deliver drug at various times or at various sites in the body, according to a stimulus that is either endogenous or externally applied. In the past three decades, research along these lines has taken numerous directions, and each new generation of investigators has discovered new physicochemical principles and chemical schemes by which the release properties of materials can be altered. No single review could possibly do justice to all of these approaches. In this article, some general observations are made, and a partial history of the field is presented. Both open loop and closed loop systems are discussed. Special emphasis is placed on stimuli-responsive hydrogels, and on systems that can respond repeatedly. It is argued that the most success at present and in the foreseeable future is with systems in which biosensing and actuation (i.e. drug delivery) are separated, with a human and/or cybernetic operator linking the two. Copyright © 2014 Elsevier B.V. All rights reserved.

High temperature corrosion of cold worked YUS409D bellows of bellow-sealed valve in LBE

NASA Astrophysics Data System (ADS)

Mustari1, A. P. A.; Irwanto1, D.; Takahashi, M.

2017-01-01

Lead-bismuth eutectic (LBE) loop test is highly contributes to the lead-alloy-cooled fast breeder reactor (LFR) and accelerator driven system (ADS) research and development by providing comprehensive results of both corrosion and erosion phenomenon. Bellows-sealed valve is a crucial part in the LBE loop test apparatus, due to its capability of preventing corrosion on valve spring, thus improves the operation time of the system. LBE is very corrosive to stainless steel by formation of oxide layer or elemental dissolution, e.g. Ni. Thus, new type of bellows for bellows-sealed valve made of nickel free material, i.e. YUS409D, is proposed to be used in the LBE. Bellows material undergo heat treatments for mechanical improvement including cold working and annealing. The thickness reduction by the heat treatments is about 90% of initial condition. Corrosion behavior of the bellows has been studied in stagnant LBE at 500 and 600 °C for 500 hours. The oxygen concentration was controlled at about 10-7 wt%. Typical oxide layers were developed on the surface. Oxidation rate was sharply increased at 600°C.

Stimuli Sensitive Polymers and Self Regulated Drug Delivery Systems: A Very Partial Review

PubMed Central

Siegel, Ronald A.

2014-01-01

Since the early days of the Journal of Controlled Release, there has been considerable interest in materials that can release drug on an “on-demand” basis. So called “stimuli-responsive” and “intelligent” systems have been designed to deliver drug at various times or at various sites in the body, according to a stimulus that is either endogenous or externally applied. In the past three decades, research along these lines has taken numerous directions, and each new generation of investigators has discovered new physicochemical principles and chemical schemes by which the release properties of materials can be altered. No single review could possibly do justice to all of these approaches. In this article, some general observations are made, and a partial history of the field is presented. Both open loop and closed loop systems are discussed. Special emphasis is placed on stimuli-responsive hydrogels, and on systems that can respond repeatedly. It is argued that the most success at present and in the foreseeable future is with systems in which biosensing and actuation (i.e. drug delivery) are separated, with a human and/or cybernetic operator linking the two. PMID:24984012

Vanadium—lithium in-pile loop for comprehensive tests of vanadium alloys and multipurpose coatings

NASA Astrophysics Data System (ADS)

Lyublinski, I. E.; Evtikhin, V. A.; Ivanov, V. B.; Kazakov, V. A.; Korjavin, V. M.; Markovchev, V. K.; Melder, R. R.; Revyakin, Y. L.; Shpolyanskiy, V. N.

1996-10-01

The reliable information on design and material properties of self-cooled Li sbnd Li blanket and liquid metal divertor under neutron radiation conditions can be obtained using the concept of combined technological and material in-pile tests in a vanadium—lithium loop. The method of in-pile loop tests includes studies of vanadium—base alloys resistance, weld resistance under mechanical stress, multipurpose coating formation processes and coatings' resistance under the following conditions: high temperature (600-700°C), lithium velocities up to 10 m/s, lithium with controlled concentration of impurities and technological additions, a neutron load of 0.4-0.5 MW/m 2 and level of irradiation doses up to 5 dpa. The design of such an in-pile loop is considered. The experimental data on corrosion and compatibility with lithium, mechanical properties and welding technology of the vanadium alloys, methods of coatings formation and its radiation tests in lithium environment in the BOR-60 reactor (fast neutron fluence up to 10 26 m -2, irradiation temperature range of 500-523°C) are presented and analyzed as a basis for such loop development.

Blowout Surge due to Interaction between a Solar Filament and Coronal Loops

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

Li, Haidong; Jiang, Yunchun; Yang, Jiayan

2017-06-20

We present an observation of the interaction between a filament and the outer spine-like loops that produces a blowout surge within one footpoint of large-scale coronal loops on 2015 February 6. Based the observation of the AIA 304 and 94 Å, the activated filament is initially embedded below a dome of a fan-spine configuration. Due to the ascending motion, the erupting filament reconnects with the outer spine-like field. We note that the material in the filament blows out along the outer spine-like field to form the surge with a wider spire, and a two-ribbon flare appears at the site ofmore » the filament eruption. In this process, small bright blobs appear at the interaction region and stream up along the outer spine-like field and down along the eastern fan-like field. As a result, a leg of the filament becomes radial and the material in it erupts, while another leg forms the new closed loops. Our results confirm that the successive reconnection occurring between the erupting filament and the coronal loops may lead to a strong thermal/magnetic pressure imbalance, resulting in a blowout surge.« less

Loop-bed combustion apparatus

DOEpatents

Shang, Jer-Yu; Mei, Joseph S.; Slagle, Frank D.; Notestein, John E.

1984-01-01

The present invention is directed to a combustion apparatus in the configuration of a oblong annulus defining a closed loop. Particulate coal together with a sulfur sorbent such as sulfur or dolomite is introduced into the closed loop, ignited, and propelled at a high rate of speed around the loop. Flue gas is withdrawn from a location in the closed loop in close proximity to an area in the loop where centrifugal force imposed upon the larger particulate material maintains these particulates at a location spaced from the flue gas outlet. Only flue gas and smaller particulates resulting from the combustion and innerparticle grinding are discharged from the combustor. This structural arrangement provides increased combustion efficiency due to the essentially complete combustion of the coal particulates as well as increased sulfur absorption due to the innerparticle grinding of the sorbent which provides greater particle surface area.

Renewable Energy Generation and Storage Models | Grid Modernization | NREL

Science.gov Websites

-the-loop testing Projects Generator, Plant, and Storage Modeling, Simulation, and Validation NREL power plants. Power Hardware-in-the-Loop Testing NREL researchers are developing software-and-hardware -combined simulation testing methods known as power hardware-in-the-loop testing. Power hardware in the loop

N-Loop Learning: Part II--An Empirical Investigation

ERIC Educational Resources Information Center

Simonin, Bernard L.

2017-01-01

Purpose: Through a survey of firm's experiences with strategic alliances and a structural equation modeling approach, the aim of this study is to stimulate further interest in modeling and empirical research in the area of N-loop learning. Although the concepts of single-loop and double-loop learning, in particular, are well established in the…

Investigation of Inner Loop Flight Control Strategies for High-Speed Research

NASA Technical Reports Server (NTRS)

Newman, Brett; Kassem, Ayman

1999-01-01

This report describes the activities and findings conducted under contract NAS1-19858 with NASA Langley Research Center. Subject matter is the investigation of suitable flight control design methodologies and solutions for large, flexible high-speed vehicles. Specifically, methodologies are to address the inner control loops used for stabilization and augmentation of a highly coupled airframe system possibly involving rigid-body motion, structural vibrations, unsteady aerodynamics, and actuator dynamics. Techniques considered in this body of work are primarily conventional-based, and the vehicle of interest is the High-Speed Civil Transport (HSCT). Major findings include 1) current aeroelastic vehicle modeling procedures require further emphasis and refinement, 2) traditional and nontraditional inner loop flight control strategies employing a single feedback loop do not appear sufficient for highly flexible HSCT class vehicles, 3) inner loop flight control systems will, in all likelihood, require multiple interacting feedback loops, and 4) Ref. H HSCT configuration presents major challenges to designing acceptable closed-loop flight dynamics.

Selection of a platinum-binding sequence in a loop of a four-helix bundle protein.

PubMed

Yagi, Sota; Akanuma, Satoshi; Kaji, Asumi; Niiro, Hiroya; Akiyama, Hayato; Uchida, Tatsuya; Yamagishi, Akihiko

2018-02-01

Protein-metal hybrids are functional materials with various industrial applications. For example, a redox enzyme immobilized on a platinum electrode is a key component of some biofuel cells and biosensors. To create these hybrid materials, protein molecules are bound to metal surfaces. Here, we report the selection of a novel platinum-binding sequence in a loop of a four-helix bundle protein, the Lac repressor four-helix protein (LARFH), an artificial protein in which four identical α-helices are connected via three identical loops. We created a genetic library in which the Ser-Gly-Gln-Gly-Gly-Ser sequence within the first inter-helical loop of LARFH was semi-randomly mutated. The library was then subjected to selection for platinum-binding affinity by using the T7 phage display method. The majority of the selected variants contained the Tyr-Lys-Arg-Gly-Tyr-Lys (YKRGYK) sequence in their randomized segment. We characterized the platinum-binding properties of mutant LARFH by using quartz crystal microbalance analysis. Mutant LARFH seemed to interact with platinum through its loop containing the YKRGYK sequence, as judged by the estimated exclusive area occupied by a single molecule. Furthermore, a 10-residue peptide containing the YKRGYK sequence bound to platinum with reasonably high affinity and basic side chains in the peptide were crucial in mediating this interaction. In conclusion, we have identified an amino acid sequence, YKRGYK, in the loop of a helix-loop-helix motif that shows high platinum-binding affinity. This sequence could be grafted into loops of other polypeptides as an approach to immobilize proteins on platinum electrodes for use as biosensors among other applications. Copyright © 2017 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

Testing of the permanent magnet material Mn-Al-C for potential use in propulsion motors for electric vehicles

NASA Technical Reports Server (NTRS)

Abdelnour, Z. A.; Mildrum, H. F.; Strnat, K. J.

1980-01-01

The development of Mn-Al-C permanent magnets is reviewed. The general properties of the material are discussed and put into perspective relative to alnicos and ferrites. The commercial material now available is described by the manufacturer's data. The traction motor designer's demands of a permanent magnet for potential use in electric vehicle drives are reviewed. From this, a list of the needed specific information is extracted. A plan for experimental work is made which would generate this information, or verify data supplied by the producer. The results of these measurements are presented in the form of tables and graphs. The tests determined magnetic design data and some mechanical strength properties. Easy axis hysteresis and demagnetization curves, recoil loops and other minor loop fields were measured over a temperature range from -50 C to +150 C. Hysteresis loops were also measured for three orthogonal directions (the easy and 2 hard axes of magnetization).

Porous Foam Based Wick Structures for Loop Heat Pipes

NASA Technical Reports Server (NTRS)

Silk, Eric A.

2012-01-01

As part of an effort to identify cost efficient fabrication techniques for Loop Heat Pipe (LHP) construction, NASA Goddard Space Flight Center's Cryogenics and Fluids Branch collaborated with the U.S. Naval Academy s Aerospace Engineering Department in Spring 2012 to investigate the viability of carbon foam as a wick material within LHPs. The carbon foam was manufactured by ERG Aerospace and machined to geometric specifications at the U.S. Naval Academy s Materials, Mechanics and Structures Machine Shop. NASA GSFC s Fractal Loop Heat Pipe (developed under SBIR contract #NAS5-02112) was used as the validation LHP platform. In a horizontal orientation, the FLHP system demonstrated a heat flux of 75 Watts per square centimeter with deionized water as the working fluid. Also, no failed start-ups occurred during the 6 week performance testing period. The success of this study validated that foam can be used as a wick structure. Furthermore, given the COTS status of foam materials this study is one more step towards development of a low cost LHP.

Emerging Science and Research Opportunities for Metals and Metallic Nanostructures

NASA Astrophysics Data System (ADS)

Handwerker, Carol A.; Pollock, Tresa M.

2014-07-01

During the next decade, fundamental research on metals and metallic nanostructures (MMNs) has the potential to continue transforming metals science into innovative materials, devices, and systems. A workshop to identify emerging and potentially transformative research areas in MMNs was held June 13 and 14, 2012, at the University of California Santa Barbara. There were 47 attendees at the workshop (listed in the Acknowledgements section), representing a broad range of academic institutions, industry, and government laboratories. The metals and metallic nanostructures (MMNs) workshop aimed to identify significant research trends, scientific fundamentals, and recent breakthroughs that can enable new or enhanced MMN performance, either alone or in a more complex materials system, for a wide range of applications. Additionally, the role that MMN research can play in high-priority research and development (R&D) areas such as the U.S. Materials Genome Initiative, the National Nanotechnology Initiative, the Advanced Manufacturing Initiative, and other similar initiatives that exist internationally was assessed. The workshop also addressed critical issues related to materials research instrumentation and the cyberinfrastructure for materials science research and education, as well as science, technology, engineering, and mathematics (STEM) workforce development, with emphasis on the United States but with an appreciation that similar challenges and opportunities for the materials community exist internationally. A central theme of the workshop was that research in MMNs has provided and will continue to provide societal benefits through the integration of experiment, theory, and simulation to link atomistic, nanoscale, microscale, and mesoscale phenomena across time scales for an ever-widening range of applications. Within this overarching theme, the workshop participants identified emerging research opportunities that are categorized and described in more detail in the following sections in terms of the following: three-dimensional (3-D) and four-dimensional (4-D) materials science. Structure evolution and the challenge of heterogeneous and multicomponent systems. The science base for property prediction across the length scales. Nanoscale phenomena at surfaces—experiment, theory, and simulation. Prediction and control of the morphology, microstructure, and properties of "bulk" nanostructured metals. Functionality and control of materials far from equilibrium. Hybrid and multifunctional materials assemblies. Materials discovery and design: enhancing the theory-simulation-experiment loop. Following an introduction, these emerging research opportunities are discussed in detail, along with challenges and opportunities for the materials community in the areas of instrumentation, cyberinfrastructure, education, and workforce development.

Control of polymer network topology in semi-batch systems

NASA Astrophysics Data System (ADS)

Wang, Rui; Olsen, Bradley; Johnson, Jeremiah

Polymer networks invariably possess topological defects: loops of different orders. Since small loops (primary loops and secondary loops) both lower the modulus of network and lead to stress concentration that causes material failure at low deformation, it is desirable to greatly reduce the loop fraction. We have shown that achieving loop fraction close to zero is extremely difficult in the batch process due to the slow decay of loop fraction with the polymer concentration and chain length. Here, we develop a modified kinetic graph theory that can model network formation reactions in semi-batch systems. We demonstrate that the loop fraction is not sensitive to the feeding policy if the reaction volume maintains constant during the network formation. However, if we initially put concentrated solution of small junction molecules in the reactor and continuously adding polymer solutions, the fractions of both primary loop and higher-order loops will be significantly reduced. There is a limiting value (nonzero) of loop fraction that can be achieved in the semi-batch system in condition of extremely slow feeding rate. This minimum loop fraction only depends on a single dimensionless variable, the product of concentration and with single chain pervaded volume, and defines an operating zone in which the loop fraction of polymer networks can be controlled through adjusting the feeding rate of the semi-batch process.

Evaluating Mathematics Achievement of Middle School Students in a Looping Environment

ERIC Educational Resources Information Center

Franz, Dana Pomykal; Thompson, Nicole L.; Fuller, Bob; Hare, R. Dwight; Miller, Nicole C.; Walker, Jacob

2010-01-01

Looping, a school structure where students remain with one group of teachers for two or more school years, is used by middle schools to meet the diverse needs of young adolescents. However, little research exists on how looping effects the academic performance of students. This study was designed to determine if looping influenced middle school…

Loop-mediated isothermal amplification (LAMP) based detection of Colletotrichum falcatum causing red rot in sugarcane

USDA-ARS?s Scientific Manuscript database

Red rot, caused by Colletotrichum falcatum, is a destructive disease prevalent in most sugarcane-producing countries. Disease-free sugarcane planting materials are essential as the pathogen spreads primarily through infected setts. The present study was undertaken to develop loop-mediated isothermal...

Further Development of Crack Growth Detection Techniques for US Test and Research Reactors

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

Kohse, Gordon; Carpenter, David M.; Ostrovsky, Yakov

One of the key issues facing Light Water Reactors (LWRs) in extending lifetimes beyond 60 years is characterizing the combined effect of irradiation and water chemistry on material degradation and failure. Irradiation Assisted Stress Corrosion Cracking (IASCC), in which a crack propagates in a susceptible material under stress in an aggressive environment, is a mechanism of particular concern. Full understanding of IASCC depends on real time crack growth data acquired under relevant irradiation conditions. Techniques to measure crack growth in actively loaded samples under irradiation have been developed outside the US - at the Halden Boiling Water Reactor, for example.more » Several types of IASCC tests have also been deployed at the MITR, including passively loaded crack growth measurements and actively loaded slow strain rate tests. However, there is not currently a facility available in the US to measure crack growth on actively loaded, pre-cracked specimens in LWR irradiation environments. A joint program between the Idaho National Laboratory (INL) and the Massachusetts Institute of Technology (MIT) Nuclear Reactor Laboratory (NRL) is currently underway to develop and demonstrate such a capability for US test and research reactors. Based on the Halden design, the samples will be loaded using miniature high pressure bellows and a compact loading mechanism, with crack length measured in real time using the switched Direct Current Potential Drop (DCPD) method. The basic design and initial mechanical testing of the load system and implementation of the DCPD method have been previously reported. This paper presents the results of initial autoclave testing at INL and the adaptation of the design for use in the high pressure, high temperature water loop at the MITR 6 MW research reactor, where an initial demonstration is planned in mid-2015. Materials considerations for the high pressure bellows are addressed. Design modifications to the loading mechanism required by the size constraints of the MITR water loop are described. The safety case for operation of the high pressure gas-driven bellows mechanism is also presented. Key issues are the design and response of systems to limit gas flow in the event of a high pressure gas leak in the in-core autoclave. Integrity of the autoclave must be maintained and reactivity effects due to voiding of the loop coolant must be shown to be within the reactor technical specifications. The technical development of the crack growth monitor for application in the INL Advanced Test Reactor or the MITR can act as a template for adaptation of this technology in other reactors. (authors)« less

The strainrange conversion principle for treating cumulative fatigue damage in the creep range

NASA Technical Reports Server (NTRS)

Manson, S. S.

1983-01-01

A formula is derived for combining effects of successive hysteresis loops in the creep range of materials when one loop has excess tensile creep, while the other contains excess compressive creep. The resultant effect resembles single loops involving balanced tensile and compressive creep. The attempt to use the Interaction Damage Rule as a tool in combining loops of non-equal size and complex strainrange content has led to important new concepts useful in future studies of creep-fatigue. It turns out that the Interaction Damage Rule is basically an expression of how a set of hysteresis loops involving only single generic strains can combine to produce the same micromechanistic damage as the loop containing the combined strainranges which it analyzes. Making use of the underlying concept of Strainrange Partitioning that only the strainrange content of a hysteresis loop governs fatigue life, not order of introducing strainranges, a rational derivation of the Interaction Damage Rule is provided, showing also how it can effectively be used to synthesize independent loops and determine both damaging and healing effects.

Closed-loop thrust and pressure profile throttling of a nitrous oxide/hydroxyl-terminated polybutadiene hybrid rocket motor

NASA Astrophysics Data System (ADS)

Peterson, Zachary W.

Hybrid motors that employ non-toxic, non-explosive components with a liquid oxidizer and a solid hydrocarbon fuel grain have inherently safe operating characteristics. The inherent safety of hybrid rocket motors offers the potential to greatly reduce overall operating costs. Another key advantage of hybrid rocket motors is the potential for in-flight shutdown, restart, and throttle by controlling the pressure drop between the oxidizer tank and the injector. This research designed, developed, and ground tested a closed-loop throttle controller for a hybrid rocket motor using nitrous oxide and hydroxyl-terminated polybutadiene as propellants. The research simultaneously developed closed-loop throttle algorithms and lab scale motor hardware to evaluate the fidelity of the throttle simulations and algorithms. Initial open-loop motor tests were performed to better classify system parameters and to validate motor performance values. Deep-throttle open-loop tests evaluated limits of stable thrust that can be achieved on the test hardware. Open-loop tests demonstrated the ability to throttle the motor to less than 10% of maximum thrust with little reduction in effective specific impulse and acoustical stability. Following the open-loop development, closed-loop, hardware-in-the-loop tests were performed. The closed-loop controller successfully tracked prescribed step and ramp command profiles with a high degree of fidelity. Steady-state accuracy was greatly improved over uncontrolled thrust.

The wire material and cross-section effect on double delta closing loops regarding load and spring rate magnitude: an in vitro study.

PubMed

Ferreira, M do A

1999-03-01

The mechanical behavior of orthodontics closing loops, with three different wire materials (stainless steel, cobalt-chromium and titanium-molybdenum) and with different cross-sections and a double delta design, was studied in tension tests. The springs were stress-relieved, except the titanium-molybdenum wires. There were 72 sample springs, divided into 33 stainless steel, 26 cobalt-chromium and 13 titanium-molybdenum, activated at 0.5 mm intervals, from neutral position to 3.0 mm. It was hypothesized that loads, after spring activation, and spring rate, are dependent on cross-section, wire material, and activation. The analysis of variance and the Tukey-Kramer test were applied to verify the differences between all coupled averages of the loads. Regression analysis was also used to verify if closing loops behavior was in accordance with Hooke's law and to obtain the spring rate. The results show that the loads are dependent on activation, cross-section, and wire material. Titanium-molybdenum 0.017 x 0.025 inch (Ormco) springs showed the smallest loads and the best spring rate. (beta = 84.9 g/mm)

Teachers' Attitudes and Perceptions of Looping and the Effect of Looping on Students' Academic Achievement

ERIC Educational Resources Information Center

Williams-Wright, Vera

2013-01-01

The purpose of this research study was two-fold. The first purpose was to investigate the impact of looping on academic achievement of students in selected public schools in Mississippi. The students' results on the 2010 and 2011 Mississippi Curriculum Test, Second Edition (MCT2) were used to determine whether looping students score differently in…

Dynamics of flare sprays. [in sun

NASA Technical Reports Server (NTRS)

Tandberg-Hanssen, E.; Martin, S. F.; Hansen, R. T.

1980-01-01

During solar cycle No. 20 new insight into the flare-spray phenomenon has been attained due to several innovations in solar optical-observing techniques (higher spatial resolution cinema-photography, tunable passband filters, multislit spectroscopy and extended angular field coronagraphs). From combined analysis of 13 well-observed sprays which occurred between 1969-1974 it is concluded that (1) the spray material originates from a preexisting active region filament which undergoes increased absorption some tens of minutes prior to the abrupt chromospheric brightening at the 'flare-start', and (2) the spray material is confined within a steadily expanding, loop-shaped (presumable magnetically controlled) envelope with part of the materials draining back down along one or both legs of the loop.

WannierTools: An open-source software package for novel topological materials

NASA Astrophysics Data System (ADS)

Wu, QuanSheng; Zhang, ShengNan; Song, Hai-Feng; Troyer, Matthias; Soluyanov, Alexey A.

2018-03-01

We present an open-source software package WannierTools, a tool for investigation of novel topological materials. This code works in the tight-binding framework, which can be generated by another software package Wannier90 (Mostofi et al., 2008). It can help to classify the topological phase of a given material by calculating the Wilson loop, and can get the surface state spectrum, which is detected by angle resolved photoemission (ARPES) and in scanning tunneling microscopy (STM) experiments. It also identifies positions of Weyl/Dirac points and nodal line structures, calculates the Berry phase around a closed momentum loop and Berry curvature in a part of the Brillouin zone (BZ).

Apparatus for Use in Determining Surface Conductivity at Microwave Frequencies

NASA Technical Reports Server (NTRS)

Hearn, Chase P. (Inventor)

1995-01-01

An apparatus is provided for use in determining surface conductivity of a flat or shaped conductive material at microwave frequencies. A plate has an electrically conductive surface with first and second holes passing through the plate. An electrically conductive material under test (MUT) is maintained in a spaced apart relationship with the electrically conductive surface of the plate by one or more nonconductive spacers. A first coupling loop is electrically shielded within the first hole while a second coupling loop is electrically shielded within the second hole. A dielectric resonator element is positioned between the first and second coupling loops, while also being positioned closer to the MUT than the electrically conductive surface of the plate. Microwave energy at an operating frequency f is supplied from a signal source to the first coupling loop while microwave energy received at the second coupling loop is measured. The apparatus is capable of measuring the Q-factor of the dielectric resonator situated in the 'cavity' existing between the electrically conductive surface of the plate and the MUT. Surface conductivity of the electrically conductive surface can be determined via interpolation using: 1 ) the measured Q-factor with the electrically conductive surface in place, and 2) the measured Q-factor when the MUT is replaced with reference standards having known surface conductivities.

Proton Irradiation Induced Effects in Titanium Carbide and Titanium Nitride: An Evaluation of Microstructures and Mechanical Properties

NASA Astrophysics Data System (ADS)

Dickerson, Clayton A.

The materials TiC and TiN have been identified as potential candidate materials for advanced coated nuclear fuel components for the gas-cooled fast reactor (GFR). While a number of their thermal and mechanical properties have been studied, little is known about how these ceramics respond to particle irradiation. The goal of this study was to investigate the radiation effects in TiC and TiN by analyzing the irradiated microstructures and mechanical properties. Irradiations of TiC and TiN were conducted with 2.6 MeV protons at the University of Wisconsin -- Madison to simulate proposed conditions expected in a reactor. Each material was subjected to three incident proton fluences resulting in doses of ˜0.2 dpa to ˜1 dpa at three temperatures, 600°C, 800°C, and 900°C. Post irradiation examination included microstructural analysis via TEM, lattice parameter determinations with XRD, and mechanical property measurements with micro indentation hardness and fracture toughness tests. The predominant irradiation induced aggregate defects found by high resolution TEM and diffraction contrast TEM in both irradiated TiC and TiN were interstitial faulted dislocation loops. Only circular loops were identified in TiC while both circular and triangular loops were present in TiN. The influences on the microstructural evolution from a high inherent density of dislocations and high porosity were also determined. The strains resulting from the development of the defective microstructures were measured with XRD and shown to be highly dependent on the density of dislocation loops. Maximum strains for the irradiated samples were on the order of 0.5%. Measurements of the fracture toughness of Tic samples were made by ion milling the surface of the samples to create micro cantilever beams which were subsequently fractured by nano indentation. The formation of high densities of dislocation loops in the irradiated samples was found to significantly decrease the material's fracture toughness.

BIOREACTOR DESIGN - OUTER LOOP LANDFILL, LOUISVILLE, KY

EPA Science Inventory

Bioreactor field demonstration projects are underway at the Outer Loop Landfill in Louisville, KY, USA. The research effort is a cooperative research effort between US EPA and Waste Management Inc. Two primary kinds of municipal waste bioreactors are under study at this site. ...

Electronic Warfare Closed Loop Laboratory (EWCLL) Antenna Motor Software and Hardware Development

DTIC Science & Technology

2016-09-01

ARL-TN-0779 ● SEP 2016 US Army Research Laboratory Electronic Warfare Closed Loop Laboratory (EWCLL) Antenna Motor Software and...Electronic Warfare Closed Loop Laboratory (EWCLL) Antenna Motor Software and Hardware Development by Neal Tesny Sensors and Electron Devices Directorate...TITLE AND SUBTITLE Electronic Warfare Closed Loop Laboratory (EWCLL) Antenna Motor Software and Hardware Development 5a. CONTRACT NUMBER 5b

High frequency, high temperature specific core loss and dynamic B-H hysteresis loop characteristics of soft magnetic alloys

NASA Technical Reports Server (NTRS)

Wieserman, W. R.; Schwarze, G. E.; Niedra, J. M.

1990-01-01

Limited experimental data exists for the specific core loss and dynamic B-H loops for soft magnetic materials for the combined conditions of high frequency and high temperature. This experimental study investigates the specific core loss and dynamic B-H loop characteristics of Supermalloy and Metglas 2605SC over the frequency range of 1 to 50 kHz and temperature range of 23 to 300 C under sinusoidal voltage excitation. The experimental setup used to conduct the investigation is described. The effects of the maximum magnetic flux density, frequency, and temperature on the specific core loss and on the size and shape of the B-H loops are examined.

On the thermal stability of coronal loop plasma

NASA Technical Reports Server (NTRS)

Antiochos, S. K.; Emslie, A. G.; Shoub, E. C.; An, C. H.

1982-01-01

The stability to thermal perturbation of static models of coronal loops is considered including the effects of cool, radiatively stable material at the loop base. The linear stability turns out to be sensitive only to the boundary conditions assumed on the velocity at the loop base. The question of the appropriate boundary conditions is discussed, and it is concluded that the free surface condition (the pressure perturbation vanishes), rather than the rigid wall (the velocity vanishes), is relevant to the solar case. The static models are found to be thermally unstable, with a growth time of the order of the coronal cooking time. The physical implications of these results for the solar corona and transition region are examined.

Equilibrium, metastability, and hysteresis in a model spin-crossover material with nearest-neighbor antiferromagnetic-like and long-range ferromagnetic-like interactions

NASA Astrophysics Data System (ADS)

Rikvold, Per Arne; Brown, Gregory; Miyashita, Seiji; Omand, Conor; Nishino, Masamichi

2016-02-01

Phase diagrams and hysteresis loops were obtained by Monte Carlo simulations and a mean-field method for a simplified model of a spin-crossover material with a two-step transition between the high-spin and low-spin states. This model is a mapping onto a square-lattice S =1 /2 Ising model with antiferromagnetic nearest-neighbor and ferromagnetic Husimi-Temperley (equivalent-neighbor) long-range interactions. Phase diagrams obtained by the two methods for weak and strong long-range interactions are found to be similar. However, for intermediate-strength long-range interactions, the Monte Carlo simulations show that tricritical points decompose into pairs of critical end points and mean-field critical points surrounded by horn-shaped regions of metastability. Hysteresis loops along paths traversing the horn regions are strongly reminiscent of thermal two-step transition loops with hysteresis, recently observed experimentally in several spin-crossover materials. We believe analogous phenomena should be observable in experiments and simulations for many systems that exhibit competition between local antiferromagnetic-like interactions and long-range ferromagnetic-like interactions caused by elastic distortions.

Numerical simulations of flares on M dwarf stars. I - Hydrodynamics and coronal X-ray emission

NASA Technical Reports Server (NTRS)

Cheng, Chung-Chieh; Pallavicini, Roberto

1991-01-01

Flare-loop models are utilized to simulate the time evolution and physical characteristics of stellar X-ray flares by varying the values of flare-energy input and loop parameters. The hydrodynamic evolution is studied in terms of changes in the parameters of the mass, energy, and momentum equations within an area bounded by the chromosphere and the corona. The zone supports a magnetically confined loop for which processes are described including the expansion of heated coronal gas, chromospheric evaporation, and plasma compression at loop footpoints. The intensities, time profiles, and average coronal temperatures of X-ray flares are derived from the simulations and compared to observational evidence. Because the amount of evaporated material does not vary linearly with flare-energy input, large loops are required to produce the energy measured from stellar flares.

Linking Outcomes to Organizational Planning.

ERIC Educational Resources Information Center

Ligon, Glynn; Jackson, Elaine

Linking Outcomes to Organizational Planning (LOOP) was initiated during the 1984-85 school year in the Austin (Texas) Independent School District. LOOP was designed to ensure that evaluation, research, and informal findings became part of the instructional planning loop; to provide information to the Superintendent on progress toward priorities…

Development Trends in Porous Adsorbents for Carbon Capture.

PubMed

Sreenivasulu, Bolisetty; Sreedhar, Inkollu; Suresh, Pathi; Raghavan, Kondapuram Vijaya

2015-11-03

Accumulation of greenhouse gases especially CO2 in the atmosphere leading to global warming with undesirable climate changes has been a serious global concern. Major power generation in the world is from coal based power plants. Carbon capture through pre- and post- combustion technologies with various technical options like adsorption, absorption, membrane separations, and chemical looping combustion with and without oxygen uncoupling have received considerable attention of researchers, environmentalists and the stake holders. Carbon capture from flue gases can be achieved with micro and meso porous adsorbents. This review covers carbonaceous (organic and metal organic frameworks) and noncarbonaceous (inorganic) porous adsorbents for CO2 adsorption at different process conditions and pore sizes. Focus is also given to noncarbonaceous micro and meso porous adsorbents in chemical looping combustion involving insitu CO2 capture at high temperature (>400 °C). Adsorption mechanisms, material characteristics, and synthesis methods are discussed. Attention is given to isosteric heats and characterization techniques. The options to enhance the techno-economic viability of carbon capture techniques by integrating with CO2 utilization to produce industrially important chemicals like ammonia and urea are analyzed. From the reader's perspective, for different classes of materials, each section has been summarized in the form of tables or figures to get a quick glance of the developments.

VICTORIA Class Submarine Human-in-the-Loop Experimentation Plan

DTIC Science & Technology

2014-06-01

1472G. VICTORIA Class Submarine Human-in-the-Loop Experimentation Plan and Preliminary Results © Her Majesty the Queen in Right of...19 th International Command and Control Research and Technology Symposium Title: VICTORIA Class Submarine Human-in-the-Loop...TYPE 3. DATES COVERED 00-00-2014 to 00-00-2014 4. TITLE AND SUBTITLE VICTORIA Class Submarine Human-in-the-Loop Experimentation Plan 5a. CONTRACT

Mini-filament Eruption as the Initiation of a Jet along Coronal Loops

NASA Astrophysics Data System (ADS)

Hong, Junchao; Jiang, Yunchun; Yang, Jiayan; Yang, Bo; Xu, Zhe; Xiang, Yongyuan

2016-10-01

Minifilament eruptions (MFEs) and coronal jets are different types of solar small-scale explosive events. We report an MFE observed at the New Vacuum Solar Telescope (NVST). As seen in the NVST Hα images, during the rising phase, the minifilament erupts outward orthogonally to its length, accompanied with a flare-like brightening at the bottom. Afterward, dark materials are found to possibly extend along the axis of the expanded filament body. The MFE is analogous to large filament eruptions. However, a simultaneous observation of the Solar Dynamics Observatory shows that a jet is initiated and flows out along nearby coronal loops during the rising phase of the MFE. Meanwhile, small hot loops, which connect the original eruptive site of the minifilament to the footpoints of the coronal loops, are formed successively. A differential emission measure analysis demonstrates that, on the top of the new small loops, a hot cusp structure exists. We conjecture that the magnetic fields of the MFE interact with magnetic fields of the coronal loops. This interaction is interpreted as magnetic reconnection that produces the jet and the small hot loops.

Testing of the permanent magnet material Mn-Al-C for potential use in propulsion motors for electric vehicles

NASA Technical Reports Server (NTRS)

Abdelnour, Z.; Mildrun, H.; Strant, K.

1981-01-01

The development of Mn-Al-C permanent magnets is reviewed. The general properties of the material are discussed and put into perspective relative to alnicos and ferrites. The traction motor designer's demands of a permanent magnet for potential use in electric vehicle drives are reviewed. Tests determined magnetic design data and mechanical strength properties. Easy axis hysteresis and demagnetization curves, recoil loops and other minor loop fields were measured over a temperature range from -50 to 150 C. Hysteresis loops were also measured for three orthogonal directions (the one easy and two hard axes of magnetization). Extruded rods of three different diameters were tested. The nonuniformity of properties over the cross section of the 31 mm diameter rod was studied. Mechanical compressive and bending strength at room temperature was determined on individual samples from the 31 mm rod.

Documentation of programs that compute 1) quasi-static tilts produced by an expanding dislocation loop in an elastic and viscoelastic material, and 2) surface shear stresses, strains, and shear displacements produced by screw dislocations in a vertical slab with modulus contrast

USGS Publications Warehouse

McHugh, Stuart

1976-01-01

The material in this report can be grouped into two categories: 1) programs that compute tilts produced by a vertically oriented expanding rectangular dislocation loop in an elastic or viscoelastic material and 2) programs that compute the shear stresses, strains, and shear displacements in a three-phase half-space (i.e. a half-space containing a vertical slab). Each section describes the relevant theory, and provides a detailed guide to the operation of the programs. A series of examples is provided at the end of each section.

Telecommunications Policy Research Conference. Competition in the Local Loop Section. Papers.

ERIC Educational Resources Information Center

Telecommunications Policy Research Conference, Inc., Washington, DC.

Four papers consider competition, new technology and economics of local telephone companies in a deregulated environment: (1) "An Engineering and Policy Analysis of Fiber Introduction into the Residential Subscriber Loop" (Marvin Sirbu, Frank Ferrante, and David Reed); (2) "Competition in the Local Loop: Pricing Carrier Access"…

Design and material selection for inverter transformer cores

NASA Technical Reports Server (NTRS)

Mclyman, W. T.

1973-01-01

Report is announced which studied magnetic properties of candidate materials for use in spacecraft transformers, static inverters, converters, and transformer-rectifier power supplies. Included are material characteristics for available alloy compositions in tabular form, including: trade names, saturated flux density, dc coercive force, loop squareness, material density, and watts per pound at 3 KHz.

Power in the loop real time simulation platform for renewable energy generation

NASA Astrophysics Data System (ADS)

Li, Yang; Shi, Wenhui; Zhang, Xing; He, Guoqing

2018-02-01

Nowadays, a large scale of renewable energy sources has been connecting to power system and the real time simulation platform is widely used to carry out research on integration control algorithm, power system stability etc. Compared to traditional pure digital simulation and hardware in the loop simulation, power in the loop simulation has higher accuracy and degree of reliability. In this paper, a power in the loop analog digital hybrid simulation platform has been built and it can be used not only for the single generation unit connecting to grid, but also for multiple new energy generation units connecting to grid. A wind generator inertia control experiment was carried out on the platform. The structure of the inertia control platform was researched and the results verify that the platform is up to need for renewable power in the loop real time simulation.

46 CFR 160.047-3 - Materials.

Code of Federal Regulations, 2010 CFR

2010-10-01

... GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) EQUIPMENT, CONSTRUCTION, AND MATERIALS... and Child § 160.047-3 Materials. (a) General. All components used in the construction of buoyant vests... loops for an adult or child size buoyant vest specified by this subpart must be 3/4-inch cotton webbing...

Magnetic loops, downflows, and convection in the solar corona

NASA Technical Reports Server (NTRS)

Foukal, P.

1978-01-01

Optical and extreme-ultraviolet observations of solar loop structures show that flows of cool plasma from condensations near the loop apex are a common property of loops associated with radiations whose maximum temperature is greater than approximately 7000 K and less than approximately 3,000,000 K. It is suggested that the mass balance of these structures indicates reconnection by means of plasma motion across field lines under rather general circumstances (not only after flares). It is shown that the cool material has lower gas pressure than the surrounding coronal medium. The density structure of the bright extreme ultraviolet loops suggests that downflows of cool gas result from isobaric condensation of plasma that is either out of thermal equilibrium with the local energy deposition rate into the corona, or is thermally unstable. The evidence is thought to indicate that magnetic fields act to induce a pattern of forced convection.

Improvement of logistics education from the point of view environmental management

NASA Astrophysics Data System (ADS)

Bányai, Á.

2009-04-01

The paper briefly presents the influence of environmental management on the improvement of the logistics education and research structure of the Department of Materials Handling and Logistics at the University of Miskolc, Hungary. The logistics, as an integrated science offers a very good possibility to demonstrate the effect of new innovative knowledge on the migration of the priorities of education and research of sciences. The importance of logistics in the field of recycling (or in wider sense in the field of environmental management) can be justified by the high proportion of logistic costs (as investment and operation costs) and these costs show that optimum logistic solutions are able to decrease the financial outcomes and lead to the establishment of a profitable system. Technological change constantly creates new demands on both education and research. The most important objective of the department is to create a unique logistics education in the country. For this reason the department offered up-to-date integrated knowledge at all level: undergraduate, master degree and PhD education. The integration of logistics means traditionally the joint use of technology of material handling, method of material flow, technology method of traffic, information technology, management sciences, production technology, marketing, market research, technology of services, mathematics and optimization, communication technology, system engineering, electronics and automation, mechatronics [1, 3]. The education and research portfolio of the department followed this tradition till 1993. The new lectures in the field of sustainability (logistics of recycling, logistics of quality management and recycling, closed loop economy, EU logistics or global logistics) became more and more important in the logistics education. The results of fast developments in closed loop economy, recycling, waste management, environmental protection are more and more used in the industry and this effected a revolutionary change in the education and research structure of logistics [2]. The European Community policy in the environment sectors aims at a high level of protection. Four principles were defined: the precautionary principle, the principle that preventive action should be taken, that environmental damages should as a priority be rectified at source and that the polluter should pay. All of these four principles have a very strong logistics background, especially in the field of import/export operations, traffic/transportation, inventory control, materials handling, fleet operations, customer service, supply chain management, distribution, strategic planning, warehousing, information systems of logistics, purchasing. These facts effect the development of different topics of logistics in each field of the education of the department: collection logistics of used products (especially WEEE), optimization of collection systems, design and control of disassembly systems, distribution of fractions of disassembled used products, design and control of recycling parks, possibilities of virtual networks in the field of recycling logistics, integration of logistics, recycling and total quality management, identification systems and recycling, etc. Within the framework of different supports our department has the opportunity to take part in European networks and research projects in the field of sustainability, environmental protection, recycling and closed loop economy. One of the biggest networks was developed within the framework of a Brite-Euram project entitled ‘Closing the loop from the product design to the end of life technologies'. The importance of logistics is certified by the fact, that this network defined the milestones of the improvement of an economically beneficial closed loop economy as quality aspects, communication and marketing, logistics and qualification. Within the frame of this project the logistics focused on the improvement of technologies (disassembly, reuse, refurbishment, remanufacturing and recycling), collection systems, and development of the concept for collection logistics and pre-disassembly, market survey in waste management. The Regional Knowledge Centre of Mechatronics and Logistics Systems was established in 2005. The overall objective of Knowledge Centre is to develop knowledge-intensive mechatronics and logistics systems in the leading edge of the world and to integrate the results in the economy and society through utilising the knowledge. The realisation of the objective requires the establishment and operation of a networking system of relations between those involved in sciences, the economy and society. The knowledge centre is a "knowledge integration tool" of the university in the field of mechanical engineering, and plays an important part in the intensification of the integration of the philosophy of sustainability into the related sciences. The program of the knowledge centre is focused on three well definable strategic fields, which are the vertical elements of the model. These are the R&D programs: world of products, materials and technologies, and integrated systems. The programs cover the implementation of seven, internationally competitive, application-oriented part tasks. These seven part tasks and the sustainability are closely related. The realisation of the part tasks through networking offers considerable results and economical-ecological benefits, forth for the participants and the region. The activities include basic and applied research, experimental development, technology transfer, as well as education and training and preparing the new scientific generation. The horizontal elements of the model are given by the utilisation of knowledge that can be interpreted in different dimensions: technical/engineering, legal, sustainability, economic, and social. The program relies on the continuation of existing relations in networks, and its regional nature is embodied in the cooperation of the higher education institutes and companies of the three counties. This publication was supported by the National Office for Research and Technology within the frame of Pázmány Péter programme. Any opinions, findings and conclusions or recommendations expressed in this material are those of the author and do not necessarily reflect the views of the National Office for Research and Technology. Literature: [1] J. Cselényi, Gy. Fischer, J. Murvai, B. Mang: Typical models of the recycling logistics of worn out product. Proceedings of XIV. International Conference on Material Handling and Warehousing in Belgrade, 1996. pp. 138-143. [2] R. Knoth, M. Hoffmann, B. Kopacek, P. Kopacek: A logistic concept to improve the re-usability of electric and electronic equipment, Electronics and the Environment, 2001. Proceedings of the 2001 IEEE International Symposium. 2001. pp. 115 - 118. [3] L. Cser, B. Mang: Cleaner Technologies and Recycling in Hungary. Proceedings of Int. Workshop on Environmental Conscious Manufacturing in Hertogenbosch, The Netherlands, 1997. pp. 48-56.

High-flux neutron source based on a liquid-lithium target

NASA Astrophysics Data System (ADS)

Halfon, S.; Feinberg, G.; Paul, M.; Arenshtam, A.; Berkovits, D.; Kijel, D.; Nagler, A.; Eliyahu, I.; Silverman, I.

2013-04-01

A prototype compact Liquid Lithium Target (LiLiT), able to constitute an accelerator-based intense neutron source, was built. The neutron source is intended for nuclear astrophysical research, boron neutron capture therapy (BNCT) in hospitals and material studies for fusion reactors. The LiLiT setup is presently being commissioned at Soreq Nuclear research Center (SNRC). The lithium target will produce neutrons through the 7Li(p,n)7Be reaction and it will overcome the major problem of removing the thermal power generated by a high-intensity proton beam, necessary for intense neutron flux for the above applications. The liquid-lithium loop of LiLiT is designed to generate a stable lithium jet at high velocity on a concave supporting wall with free surface toward the incident proton beam (up to 10 kW). During off-line tests, liquid lithium was flown through the loop and generated a stable jet at velocity higher than 5 m/s on the concave supporting wall. The target is now under extensive test program using a high-power electron-gun. Up to 2 kW electron beam was applied on the lithium flow at velocity of 4 m/s without any flow instabilities or excessive evaporation. High-intensity proton beam irradiation will take place at SARAF (Soreq Applied Research Accelerator Facility) superconducting linear accelerator currently in commissioning at SNRC.

High-flux neutron source based on a liquid-lithium target

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

Halfon, S.; Feinberg, G.; Paul, M.

2013-04-19

A prototype compact Liquid Lithium Target (LiLiT), able to constitute an accelerator-based intense neutron source, was built. The neutron source is intended for nuclear astrophysical research, boron neutron capture therapy (BNCT) in hospitals and material studies for fusion reactors. The LiLiT setup is presently being commissioned at Soreq Nuclear research Center (SNRC). The lithium target will produce neutrons through the {sup 7}Li(p,n){sup 7}Be reaction and it will overcome the major problem of removing the thermal power generated by a high-intensity proton beam, necessary for intense neutron flux for the above applications. The liquid-lithium loop of LiLiT is designed to generatemore » a stable lithium jet at high velocity on a concave supporting wall with free surface toward the incident proton beam (up to 10 kW). During off-line tests, liquid lithium was flown through the loop and generated a stable jet at velocity higher than 5 m/s on the concave supporting wall. The target is now under extensive test program using a high-power electron-gun. Up to 2 kW electron beam was applied on the lithium flow at velocity of 4 m/s without any flow instabilities or excessive evaporation. High-intensity proton beam irradiation will take place at SARAF (Soreq Applied Research Accelerator Facility) superconducting linear accelerator currently in commissioning at SNRC.« less

LOOP: Linking Outcomes to Organizational Planning, First Quarterly Report: 25 School Board Priorities.

ERIC Educational Resources Information Center

Ligon, Glynn; Wicker, Maria L. R.

The Austin Independent School District Superintendent of Schools required a process for monitoring district activities. The Office of Research and Evaluation developed LOOP (Linking Outcomes to Organizational Planning). LOOP is a management information system through which progress in a number of activities within the school system may be…

Use of Double-Loop Learning to Combat Advanced Persistent Threat: Multiple Case Studies

ERIC Educational Resources Information Center

Lamb, Christopher J.

2013-01-01

The Advanced Persistent Threat (APT) presents an ever present and more growing threat to organizations across the globe. Traditional Information Technology (IT) incident response falls short in effectively addressing this threat. This researcher investigated the use of single-loop and double-loop learning in two organizations with internal…

Identification of processed Chinese medicinal materials using DNA mini-barcoding.

PubMed

Song, Ming; Dong, Gang-Qiang; Zhang, Ya-Qin; Liu, Xia; Sun, Wei

2017-07-01

Most of Chinese medicinal herbs are subjected to traditional processing procedures, including stir-frying, charring, steaming, boiling, and calcining before they are released into dispensaries. The marketing and identification of processed medicinal materials is a growing issue in the marketplace. However, conventional methods of identification have limitations, while DNA mini-barcoding, based on the sequencing of a short-standardized region, has received considerable attention as a new potential means to identify processed medicinal materials. In the present study, six DNA barcode loci including ITS2, psbA-trnH, rbcL, matK, trnL (UAA) intron and its P6 loop, were employed for the authentication of 45 processed samples belonging to 15 species. We evaluated the amplification efficiency of each locus. We also examined the identification accuracy of the potential mini-barcode locus, of trnL (UAA) intron P6 loop. Our results showed that the five primary barcode loci were successfully amplified in only 8.89%-20% of the processed samples, while the amplification rates of the trnL (UAA) intron P6 loop were higher, at 75.56% successful amplification. We compared the mini-barcode sequences with Genbank using the Blast program. The analysis showed that 45.23% samples could be identified to genus level, while only one sample could be identified to the species level. We conclude that trnL (UAA) p6 loop is a candidate mini-barcode that has shown its potential and may become a universal mini-barcode as complementary barcode for authenticity testing and will play an important role in medicinal materials control. Copyright © 2017 China Pharmaceutical University. Published by Elsevier B.V. All rights reserved.

NY TBO Research: Integrated Demand Management (IDM): IDM Concept, Tools, and Training Package

NASA Technical Reports Server (NTRS)

Smith, Nancy

2016-01-01

A series of human-in-the-loop simulation sessions were conducted in the Airspace Operations Laboratory (AOL) to evaluate a new traffic management concept called Integrated Demand Management (IDM). The simulation explored how to address chronic equity, throughput and delay issues associated with New Yorks high-volume airports by operationally integrating three current and NextGen capabilities the Collaborative Trajectory Options Program (CTOP), Time-Based Flow Management (TBFM) and Required Time of Arrival (RTA) in order to better manage traffic demand within the National Air Traffic System. A package of presentation slides was developed to describe the concept, tools, and training materials used in the simulation sessions. The package will be used to outbrief our stakeholders by both presenting orally and disseminating of the materials via email.

Shape Morphing Adaptive Radiator Technology (SMART) Updates to Techport Entry

NASA Technical Reports Server (NTRS)

Erickson, Lisa; Bertagne, Christopher; Hartl, Darren; Witcomb, John; Cognata, Thomas

2017-01-01

The Shape-Morphing Adaptive Radiator Technology (SMART) project builds off the FY16 research effort that developed a flexible composite radiator panel and demonstrated its ability to actuate from SMA's attached to it. The proposed FY17 Shape-Morphing Adaptive Radiator Technology (SMART) project's goal is to 1) develop a practical radiator design with shape memory alloys (SMAs) bonded to the radiator's panel, and 2) build a multi-panel radiator prototype for subsequent system level thermal vacuum tests. The morphing radiator employs SMA materials to passively change its shape to adapt its rate of heat rejection to vehicle requirements. Conceptually, the radiator panel has a naturally closed position (like a cylinder) in a cold environment. Whenever the radiator's temperature gradually rises, SMA's affixed to the face sheet will pull the face sheet open a commensurate amount - increasing the radiators view to space and causing it to reject more heat. In a vehicle, the radiator's variable heat rejection capabilities would reduce the number of additional heat rejection devices in a vehicle's thermal control system. This technology aims to help achieve the required maximum to minimum heat rejection ratio required for manned space vehicles to adopt a lighter, simpler, single loop thermal control architecture (ATCS). Single loop architectures are viewed as an attractive means to reduce mass and complexity over traditional dual-loop solutions. However, fluids generally considered safe enough to flow within crewed cabins (e.g. propylene glycol-water mixtures) have much higher freezing points and viscosities than those used in the external sides of dual loop ATCSs (e.g. Ammonia and HFE7000).

Improvement in thrust force estimation of solenoid valve considering minor hysteresis loop

NASA Astrophysics Data System (ADS)

Yoon, Myung-Hwan; Choi, Yun-Yong; Hong, Jung-Pyo

2017-05-01

Solenoid valve is a very important hydraulic actuator for an automatic transmission in terms of shift quality. The same form of pressure for the clutch and the input current are required for an ideal control. However, the gap between a pressure and a current can occur which brings a delay in a transmission and a decrease in quality. This problem is caused by hysteresis phenomenon. As the ascending or descending magnetic field is applied to the solenoid, different thrust forces are generated. This paper suggests the calculation method of the thrust force considering the hysteresis phenomenon and consequently the accurate force can be obtained. Such hysteresis occurs in ferromagnetic materials, however the hysteresis phenomenon includes a minor hysteresis loop which begins with an initial magnetization curve and is generated by DC biased field density. As the core of the solenoid is ferromagnetic material, an accurate thrust force is obtained by applying the minor hysteresis loop compared to the force calculated by considering only the initial magnetization curve. An analytical background and the detailed explanation of measuring the minor hysteresis loop are presented. Furthermore experimental results and finite element analysis results are compared for the verification.

Quasiparticle interference mapping of ZrSiS

NASA Astrophysics Data System (ADS)

Lodge, Michael; Hosen, Md Mofazzle; Neupane, Madhab; Ishigami, Masa; Chang, Guoqing; Singh, Bahadur; Lin, Hsin; Weber, Bent; Hellerstedt, Jack; Edmonds, Mark; Fuhrer, Michael; Kaczorowski, Dariusz

The emergent class of 3D Dirac semimetals presents intriguing new systems in which to study the rich physics of the robust, topologically-protected quasiparticles hosted within their bulk. For example, in nodal-line Dirac semimetals, the conductance and valence bands meet along a closed loop in momentum space and disperse linearly in the vicinity of the resultant line node. This results in novel scattering phenomena, owing to the unique Fermi surfaces and scattering selection rules of these systems. Here, we have performed scanning tunneling microscopy and spectroscopy of ZrSiS, one such nodal-line Dirac semimetal,at 4.5 K. We have visualized quasiparticle scattering using differential conductance mapping. In conjunction with numerical modeling, we identify at least six allowed scattering vectors in the material, which gives insight into the scattering selection rules of these novel materials. This work is based upon research supported by the National Science Foundation under Grant No. 0955625 (MSL and MI) and Fellowship No. 1614303 (MSL), and by the Australian Research Council under DECRA Fellowship No. DE160101334 (BW).

ISS Material Science Research Rack HWIL Interface Simulation

NASA Technical Reports Server (NTRS)

Williams, Philip J.; Ballard, Gary H.; Crumbley, Robert T. (Technical Monitor)

2002-01-01

In this paper, the first Material Science Research Rack (MSRR-1) hardware-in-the-loop (HWIL) interface simulation is described. Dynamic Concepts developed this HWIL simulation system with funding and management provided by the Flight Software group (ED14) of NASA-MSFC's Avionics Department. The HWIL system has been used both as a flight software development environment and as a software qualification tool. To fulfill these roles, the HWIL simulator accurately models the system dynamics of many MSRR-1 subsystems and emulates most of the internal interface signals. The modeled subsystems include the Experiment Modules, the Thermal Environment Control System, the Vacuum Access System, the Solid State Power Controller Module, and the Active Rack Isolation Systems. The emulated signals reside on three separate MIL-STD-1553B digital communication buses, the ISS Medium Rate Data Link, and several analog controller and sensor signals. To enhance the range of testing, it was necessary to simulate several off-nominal conditions that may occur in the interfacing subsystems.

Preisach modeling of piezoceramic and shape memory alloy hysteresis

NASA Astrophysics Data System (ADS)

Hughes, Declan; Wen, John T.

1997-06-01

Smart materials such as piezoceramics, magnetostrictive materials, and shape memory alloys exhibit hysteresis, and the larger the input signal the larger the effect. Hysteresis can lead to unwanted harmonics, inaccuracy in open loop control, and instability in closed loop control. The Preisach independent domain hysteresis model has been shown to capture the major features of hysteresis arising in ferromagnetic materials. Noting the similarity between the microscopic domain kinematics that generate static hysteresis effects in ferromagnetics, piezoceramics, and shape memory alloys (SMAs), we apply the Preisach model for the hysteresis in piezoceramic and shape memory alloy materials. This paper reviews the basic properties of the Preisach model, discusses control-theoretic issues such as identification, simulation, and inversion, and presents experimental results for piezoceramic sheet actuators bonded to a flexible aluminum beam, and a Nitinol SMA wire muscle that applies a bending force to the end of a beam.

Preisach modeling of piezoceramic and shape memory alloy hysteresis

NASA Astrophysics Data System (ADS)

Hughes, Declan C.; Wen, John T.

1996-05-01

Smart materials such as piezoceramics, magnetostrictive materials, and shape memory alloys exhibit significant hysteresis, especially when driven with large input signals. Hysteresis can lead to unwanted harmonics, inaccuracy in open loop control, and instability in closed loop control. The Preisach independent domain hysteresis model has been shown to capture the major features of hysteresis arising in ferromagnetic materials. Noting the similarity between the microscopic domain kinematics that generate static hysteresis effects in ferromagnetics, piezoceramics, and shape memory alloys, we apply the Preisach model for the hysteresis in piezoceramic and shape memory alloy materials. This paper reviews the basic properties of the Preisach model, discusses control-theoretic issues such as identification, simulation, and inversion, and presents experimental results for piezoceramic sheet actuators bonded to a flexible aluminum beam, and a Nitinol SMA wire muscle that applies a bending force to the end of a beam.

Comparison of the CO2 laser and Leep-Loop method in treatment of changes in uterine cervix

NASA Astrophysics Data System (ADS)

Wozniak, Jakub; Wilczak, Maciej; Sajdak, Stefan; Opala, Tomasz; Rabiega, Dorota

2000-11-01

Electric leep-loop and lasersurgery are modern methods in treatment of diseases of uterine cervix that we can use often exchangeable. Differences first of all relates indications. Lasersurgery we can apply in diseases of uterine cervix channel. Application of electric leep in dysplasia of small grade of uterus cervix channel is possible. Before lasersurgery we should exclude cervical carcinoma, because we don't have histopathological material. Leep-loop conisation we shouldn't apply at young women, who plan pregnancy (risk of cicatristaion and dystokia of uterine cervix.)

Active vibration damping using smart material

NASA Technical Reports Server (NTRS)

Baras, John S.; Yan, Zhuang

1994-01-01

We consider the modeling and active damping of an elastic beam using distributed actuators and sensors. The piezoelectric ceramic material (PZT) is used to build the actuator. The sensor is made of the piezoelectric polymer polyvinylidene fluoride (PVDF). These materials are glued on both sides of the beam. For the simple clamped beam, the closed loop controller has been shown to be able to extract energy from the beam. The shape of the actuator and its influence on the closed loop system performance are discussed. It is shown that it is possible to suppress the selected mode by choosing the appropriate actuator layout. It is also shown that by properly installing the sensor and determining the sensor shape we can further extract and manipulate the sensor signal for our control need.

FINE STRUCTURES AND OVERLYING LOOPS OF CONFINED SOLAR FLARES

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

Yang, Shuhong; Zhang, Jun; Xiang, Yongyuan, E-mail: shuhongyang@nao.cas.cn

2014-10-01

Using the Hα observations from the New Vacuum Solar Telescope at the Fuxian Solar Observatory, we focus on the fine structures of three confined flares and the issue why all the three flares are confined instead of eruptive. All the three confined flares take place successively at the same location and have similar morphologies, so can be termed homologous confined flares. In the simultaneous images obtained by the Solar Dynamics Observatory, many large-scale coronal loops above the confined flares are clearly observed in multi-wavelengths. At the pre-flare stage, two dipoles emerge near the negative sunspot, and the dipolar patches aremore » connected by small loops appearing as arch-shaped Hα fibrils. There exists a reconnection between the small loops, and thus the Hα fibrils change their configuration. The reconnection also occurs between a set of emerging Hα fibrils and a set of pre-existing large loops, which are rooted in the negative sunspot, a nearby positive patch, and some remote positive faculae, forming a typical three-legged structure. During the flare processes, the overlying loops, some of which are tracked by activated dark materials, do not break out. These direct observations may illustrate the physical mechanism of confined flares, i.e., magnetic reconnection between the emerging loops and the pre-existing loops triggers flares and the overlying loops prevent the flares from being eruptive.« less

Evaluation of the reverse transcription loop-mediated isothermal amplification (RT-LAMP) as a screening method for the detection of influenza viruses in the fecal materials of water birds.

PubMed

Yoshida, Hiromi; Sakoda, Yoshihiro; Endo, Mayumi; Motoshima, Masayuki; Yoshino, Fumi; Yamamoto, Naoki; Okamatsu, Masatoshi; Soejima, Takahiro; Senba, Syouhei; Kanda, Hidetoshi; Kida, Hiroshi

2011-06-01

Migratory water birds are a natural reservoir for influenza A viruses. Viruses replicate in the intestines of ducks and are shed with the fecal materials. Virus isolation from collected fecal materials, therefore, is an integral part of the surveillance of avian influenza in water birds. In the present study, reverse transcription loop-mediated isothermal amplification (RT-LAMP) was assessed for its usefulness in detecting the RNA of influenza A viruses in fecal materials. It was found that, RT-LAMP specifically and sensitively detects the matrix gene of influenza A viruses. Influenza A viruses were isolated from the fecal materials in which viral RNA were detected by RT-LAMP in 35 min. The present findings indicate that RT-LAMP is useful as a high throughput screening method for field samples prior to virus isolation, allowing the processing of hundreds of samples per day.

Integrated Research/Education University Aircraft Design Program Development

DTIC Science & Technology

2017-04-06

iterations and loop shaping compared to MIMO control methods. Despite the drawbacks, loop closure and classical methods are the design methods most commonly...AFRL-AFOSR-VA-TR-2017-0077 Integrated Research/Education University Aircraft Design Program Development Eli Livne UNIVERSITY OF WASHINGTON 4333...SUBTITLE Integrated Research/Education University Aircraft Design Program Development 5a.  CONTRACT NUMBER 5b.  GRANT NUMBER FA9550-14-1-0027 5c.  PROGRAM

Explaining Warm Coronal Loops

NASA Technical Reports Server (NTRS)

Klimchuk, James A.; Karpen, Judy T.; Patsourakos, Spiros

2008-01-01

One of the great mysteries of coronal physics that has come to light in the last few years is the discovery that warn (- 1 INK) coronal loops are much denser than expected for quasi-static equilibrium. Both the excess densities and relatively long lifetimes of the loops can be explained with bundles of unresolved strands that are heated impulsively to very high temperatures. Since neighboring strands are at different stages of cooling, the composite loop bundle is multi-thermal, with the distribution of temperatures depending on the details of the "nanoflare storm." Emission hotter than 2 MK is predicted, but it is not clear that such emission is always observed. We consider two possible explanations for the existence of over-dense warm loops without corresponding hot emission: (1) loops are bundles of nanoflare heated strands, but a significant fraction of the nanoflare energy takes the form of a nonthermal electron beam rather then direct plasma heating; (2) loops are bundles of strands that undergo thermal nonequilibrium that results when steady heating is sufficiently concentrated near the footpoints. We present numerical hydro simulations of both of these possibilities and explore the observational consequences, including the production of hard X-ray emission and absorption by cool material in the corona.

ESF GROUND SUPPORT - MATERIAL DEDICATION ANALYSIS FOR STRUCTURAL STEEL AND ACCESSORIES FROM A COMMERCIAL GRADE SOURCE

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

M.D. Stine

1996-01-23

The purpose of this analysis is to select the critical characteristics to be verified for steel sets and accessories and the verification methods to be implemented through a material dedication process for the procurement and use of commercial grade structural steel sets and accessories (which have a nuclear safety function) to be used in ground support (with the exception of alcove ground support and alcove opening framing, which are not addressed in this analysis) for the Exploratory Studies Facility (ESF) Topopah Spring (TS) Loop. The ESF TS Loop includes the North Ramp, Main Drift, and South Ramp underground openings.

The Role of the Phonological Loop in English Word Learning: A Comparison of Chinese ESL Learners and Native Speakers

ERIC Educational Resources Information Center

Hamada, Megumi; Koda, Keiko

2011-01-01

Although the role of the phonological loop in word-retention is well documented, research in Chinese character retention suggests the involvement of non-phonological encoding. This study investigated whether the extent to which the phonological loop contributes to learning and remembering visually introduced words varies between college-level…

Energy Systems Integration News | Energy Systems Integration Facility |

Science.gov Websites

photovoltaic (PV) energy for its power. PV inverter hardware-in the loop testing was conducted at NREL's Energy -scale power-hardware-in-the-loop testing at the ESIF, which allows researchers and manufacturers to test field. In addition, the CGI provides hardware-in-the-loop capability combined with NWTC dynamometers

Development of near real time performance measurements for closed-loop signal systems (CLS) using historical traffic data from existing loop detectors and signal timing data.

DOT National Transportation Integrated Search

2014-10-01

The overarching goal of this research project was to investigate the potential for the NCDOT Central Office Signal Timing : (COST) Section to monitor and assess the quality of field deployed closed-loop signal system plans using the data inherent in ...

Fort Knox, KY Containment Berm Unit Installation

DTIC Science & Technology

2013-02-01

There is interest from the range community in establishing a sustainable, closed loop small arms firing range (SAFR) bullet impact system or Containment... system . The metals from the bullets will be retained, stabilized, in the berm material with the addition of proper amendments. Following sufficient...replaced or placed back in the connex. This provides a closed loop containment system for sustainable range training purposes. The Containment Berm

Centrifuge Testing of a Partially-Confined FC-72 Spray

DTIC Science & Technology

2006-11-01

induced body forces. Heat transfer associated with closed - loop spray cooling will be affected by acceleration body forces, the extent of which is not...impingement cooling, spray cooling, heat pipes , loop heat pipes , carbon foam impregnated with phase-change materials, and combinations of the above...reduced gravity and elevated gravity experiments to help prove viability of pulsating heat pipes (PHPs) for space applications. The PHPs, filled

Rotor systems research aircraft simulation mathematical model

NASA Technical Reports Server (NTRS)

Houck, J. A.; Moore, F. L.; Howlett, J. J.; Pollock, K. S.; Browne, M. M.

1977-01-01

An analytical model developed for evaluating and verifying advanced rotor concepts is discussed. The model was used during in both open loop and real time man-in-the-loop simulation during the rotor systems research aircraft design. Future applications include: pilot training, preflight of test programs, and the evaluation of promising concepts before their implementation on the flight vehicle.

Advanced physical-chemical life support systems research

NASA Technical Reports Server (NTRS)

Evanich, Peggy L.

1988-01-01

A proposed NASA space research and technology development program will provide adequate data for designing closed loop life support systems for long-duration manned space missions. This program, referred to as the Pathfinder Physical-Chemical Closed Loop Life Support Program, is to identify and develop critical chemical engineering technologies for the closure of air and water loops within the spacecraft, surface habitats or mobility devices. Computerized simulation can be used both as a research and management tool. Validated models will guide the selection of the best known applicable processes and in the development of new processes. For the integration of the habitat system, a biological subsystem would be introduced to provide food production and to enhance the physical-chemical life support functions on an ever-increasing basis.

Substrate With Low Secondary Emissions

NASA Technical Reports Server (NTRS)

Jensen, Kenneth A. (Inventor); Curren, Arthur N. (Inventor); Roman, Robert F. (Inventor)

2000-01-01

The present invention is directed to a method and apparatus for producing a highly -textured surface on a copper substrate -with only extremely small amounts of texture-inducing seeding or masking material. The texture-inducing seeding material is delivered to the copper substrate electrically switching the seeding material in and out of a circuit loop.

MULTI-MEDIA CATALOG OF THE INSTRUCTIONAL MATERIALS CENTER.

ERIC Educational Resources Information Center

Saginaw County Intermediate School District, MI.

THIS IS A LISTING OF MATERIALS FOR K-12 AVAILABLE FOR TEACHERS AND PLANNERS, INCLUDING FILM LOOPS, TAPE RECORDINGS, FILMSTRIPS, SLIDES, TRANSPARENCIES, RECORDS, STUDY AND ART PRINTS, MODELS AND REALIA, SCULPTURE AND KITS. AN OVERALL SUBJECT INDEX IS FOLLOWED BY SEPARATE SUBJECT LISTS FOR EACH TYPE OF MATERIAL. A BRIEF DESCRIPTION OF EACH…

NETL - Thermogravimetric Analysis Laboratory

ScienceCinema

Richards, George

2018-06-22

Researchers in NETL's Thermal Analysis Laboratory are investigating chemical looping combustion. As a clean and efficient fossil fuel technology, chemical looping combustion controls CO2 emissions and offers a promising alternative to traditional combustion.

Automated Droplet Manipulation Using Closed-Loop Axisymmetric Drop Shape Analysis.

PubMed

Yu, Kyle; Yang, Jinlong; Zuo, Yi Y

2016-05-17

Droplet manipulation plays an important role in a wide range of scientific and industrial applications, such as synthesis of thin-film materials, control of interfacial reactions, and operation of digital microfluidics. Compared to micron-sized droplets, which are commonly considered as spherical beads, millimeter-sized droplets are generally deformable by gravity, thus introducing nonlinearity into control of droplet properties. Such a nonlinear drop shape effect is especially crucial for droplet manipulation, even for small droplets, at the presence of surfactants. In this paper, we have developed a novel closed-loop axisymmetric drop shape analysis (ADSA), integrated into a constrained drop surfactometer (CDS), for manipulating millimeter-sized droplets. The closed-loop ADSA generalizes applications of the traditional drop shape analysis from a surface tension measurement methodology to a sophisticated tool for manipulating droplets in real time. We have demonstrated the feasibility and advantages of the closed-loop ADSA in three applications, including control of drop volume by automatically compensating natural evaporation, precise control of surface area variations for high-fidelity biophysical simulations of natural pulmonary surfactant, and steady control of surface pressure for in situ Langmuir-Blodgett transfer from droplets. All these applications have demonstrated the accuracy, versatility, applicability, and automation of this new ADSA-based droplet manipulation technique. Combining with CDS, the closed-loop ADSA holds great promise for advancing droplet manipulation in a variety of material and surface science applications, such as thin-film fabrication, self-assembly, and biophysical study of pulmonary surfactant.

The looped adhesive strip: An example of coplanar delamination interaction

NASA Technical Reports Server (NTRS)

Bottega, W. J.

1990-01-01

The phenomenon of peeling and debonding of thin layers is a subject of interest to those concerned with adhesives, thin films, and layered materials. In recent years much attention has been focused on such problems as a result of increased interest and application of advanced composites and thin film coatings. A related problem which is of interest for its own sake but also represents a simple example of a tangled adhesive strip and of coplanar delamination interaction, is the problem of a looped adhesive strip. This is the subject of the present study. Researchers consider here the problem of an elastic strip which possesses an adherend on (at least) one of its surfaces. If the strip is deformed so that two portions of such a surface are brought into contact, a position of the strip becomes bonded and a loop is formed. Researchers are interested in determining the equilibrium configuration of such a strip and investigating the behavior of the strip when its edges are pulled apart. The problem is approached as a moving interior boundary problem in the calculus of variations with the strip modeled as an inextensible elastica and the bond strength characterized by its surface energy. A Griffith type energy criterion is employed for debonding, and solutions corresponding to the problem of interest obtained. The solution obtained will be seen to predict the interesting phenomenon of bond point propagation, as well as the more standard peeling type behavior. Numerical results demonstrating the phenomena of interest are presented as well and will be seen to reveal both stable and unstable propagation of the boundaries of the bonded portion of the strip, depending upon the loading conditions.

Characterization of fine-grain piezoceramic stack actuators

NASA Astrophysics Data System (ADS)

Davis, Christopher L.; Morris, Donald G.; Calkins, Frederick T.

2001-07-01

Samples of fine grain piezoelectric ceramics (less than or equal to 1 micrometers ) exhibit increased mechanical strength and improved machinability over conventional materials, which should result in actuators which have increased reliability with fewer rejected parts. The focus of the work presented here is to compare the properties of several fine grain and conventional actuators provided by TRS Ceramics. Specimens are constructed of TRS200 (a PZT-5A or DOD Type II equivalent material) and TRS600 (a PZT-5H or DOD Type VI equivalent material). All of the actuators consist of ceramic wafers bonded together with electrodes between them to form a stack. Several actuator overall dimensions and two wafer thicknesses (250 micrometers and 500 micrometers ) are investigated as well as material which has been subjected to hot isopress. The two main figures of merit in the stack actuator comparisons are free strain and blocked stress. Strain and stress loops are measured under a variety of field levels, including negative fields up to the coercive limit (full butterfly loops were not performed). Also compared are values of energy density and hysteresis in the strain, stress and electric displacement vs. field loops. Stack longevity is addressed through duration tests in which stacks are used to drive representative mechanical impedance for an extended period. Results show that fine grain stacks completed 109 continuous actuation cycles with no sign of performance degradation.

The magnetization process: Hysteresis

NASA Technical Reports Server (NTRS)

Balsamel, Richard

1990-01-01

The magnetization process, hysteresis (the difference in the path of magnetization for an increasing and decreasing magnetic field), hysteresis loops, and hard magnetic materials are discussed. The fabrication of classroom projects for demonstrating hysteresis and the hysteresis of common magnetic materials is described in detail.

Mesohysteresis model for ferromagnetic materials by minimization of the micromagnetic free energy

NASA Astrophysics Data System (ADS)

van den Berg, A.; Dupré, L.; Van de Wiele, B.; Crevecoeur, G.

2009-04-01

To study the connection between macroscopic hysteretic behavior and the microstructural properties, this paper presents and validates a new material dependent three-dimensional mesoscopic magnetic hysteresis model. In the presented mesoscopic description, the different micromagnetic energy terms are reformulated on the space scale of the magnetic domains. The sample is discretized in cubic cells, each with a local stress state, local bcc crystallographic axes, etc. The magnetization is assumed to align with one of the three crystallographic axes, in positive or negative sense, defining six volume fractions within each cell. The micromagnetic Gibbs free energy is described in terms of these volume fractions. Hysteresis loops are computed by minimizing the mesoscopic Gibbs free energy using a modified gradient search for a sequence of external applied fields. To validate the mesohysteresis model, we studied the magnetic memory properties. Numerical experiments reveal that (1) minor hysteresis loops are indeed closed and (2) the closed minor loops are erased from the memory.

Application of a Loop-Type Laboratory Biofilm Reactor to the Evaluation of Biofilm for Some Metallic Materials and Polymers such as Urinary Stents and Catheters.

PubMed

Kanematsu, Hideyuki; Kudara, Hikonaru; Kanesaki, Shun; Kogo, Takeshi; Ikegai, Hajime; Ogawa, Akiko; Hirai, Nobumitsu

2016-10-11

A laboratory biofilm reactor (LBR) was modified to a new loop-type closed system in order to evaluate novel stents and catheter materials using 3D optical microscopy and Raman spectroscopy. Two metallic specimens, pure nickel and cupronickel (80% Cu-20% Ni), along with two polymers, silicone and polyurethane, were chosen as examples to ratify the system. Each set of specimens was assigned to the LBR using either tap water or an NB (Nutrient broth based on peptone from animal foods and beef extract mainly)-cultured solution with E-coli formed over 48-72 h. The specimens were then analyzed using Raman Spectroscopy. 3D optical microscopy was employed to corroborate the Raman Spectroscopy results for only the metallic specimens since the inherent roughness of the polymer specimens made such measurements difficult. The findings suggest that the closed loop-type LBR together with Raman spectroscopy analysis is a useful method for evaluating biomaterials as a potential urinary system.

The Psychological Costs of Knowledge Specialization in Groups: Unique Expertise Leaves You out of the Loop

ERIC Educational Resources Information Center

Jones, Eric E.; Kelly, Janice R.

2013-01-01

Knowledge specialization, such as that present in cross-functional teams, produces both positive and negative outcomes. Our research investigated how unique expertise can lead to feelings of ostracism in the form of being out of the loop. Compared to group members with shared expertise, members with unique expertise felt out of the loop and…

The Impact of Curriculum Looping on Standardized Literacy and Mathematics Test Scores

ERIC Educational Resources Information Center

Nessler, Ralph D.

2010-01-01

There is a lack of research on the practice of curriculum looping and student achievement. The purpose of this study was to examine academic achievement between students in looping classes and those in nonlooping classes. The theoretical model of this study was based on the social cognitive theory of Bandura and Maslow's hierarchy of needs theory.…

Investigation of fluvial landforms in the north-eastern Pannonian Basin, using cartographic materials from the XIX-XXI Centuries

NASA Astrophysics Data System (ADS)

Robu, Delia; Niga, Bogdan; Perşoiu, Ioana

2015-04-01

The study area is located in the north-eastern Pannonian Basin, and covers approximately 3700 km2. Using cartographic materials for the last 155 years, we analyzed and defined river network and relict fluvial morphologies created by the rivers Tur, Someş, Homorod and Crasna. Database extraction from each set of historical maps was performed by field verification and validation, associated to GIS techniques. Relict fluvial morphologies on the Someş alluvial cone comprise a wide variety of channel typologies and sizes, drainage directions and their consequent typology, which indicates a complex fluvial evolution. The dominant category of relict fluvial morphology is represented by the meander loop. Following the quantitative analysis on the successive sets of maps we identified and delimited meander loops and meandering paths formed prior to the reference year 1860. Generally, the post-1860 relict fluvial morphologies are secondary morphologies, as the keynote is given by those formed previous to the reference moment 1860. An analysis of the share of the relict fluvial morphologies on the three sets of reference cartographic materials (the second Austro-Hungarian topographic survey, Google Earth and orthophotoplans) highlights that most relict fluvial morphologies were identified on the second Austro-Hungarian topographic survey, followed by those identified in Google Earth and orthophotoplans. The map of fluvial morphologies constructed in this study enables a discussion on drainage directions, based on the observation that a series of abandoned meander loops and segments follow clear directions. We applied several quantitative indices in assessing the relict fluvial morphology (radius of curvature, paleochannel width). Consequently, we identified underfit stream sectors with meander loops larger than the modern ones Someş meanders (on the Racta River), uncharacteristic features such as braided riverbed reaches, a high frequency of meander scrolls present on the right bank of Crasna at its entrance in the plain, or the occurrence of wetlands in an area affected by subsidence (the Ecedeea Plain). Despite the ample human intervention in our study area through sewers, dams, meander cuts, the river network evolution trend remained the same between 1860 and 2005, with evolution and formation of meanders, although the change rate has diminished. "ACKNOWLEDGMENT This paper has been financially supported within the project entitled "SOCERT. Knowledge society, dynamism through research", contract number POSDRU/159/1.5/S/132406. This project is co-financed by European Social Fund through Sectoral Operational Programme for Human Resources Development 2007-2013. Investing in people!"

Solar Scientist Confirm Existence of Flux Ropes on the Sun

NASA Image and Video Library

2013-02-14

Caption: This is an image of magnetic loops on the sun, captured by NASA's Solar Dynamics Observatory (SDO). It has been processed to highlight the edges of each loop to make the structure more clear. A series of loops such as this is known as a flux rope, and these lie at the heart of eruptions on the sun known as coronal mass ejections (CMEs.) This is the first time scientists were able to discern the timing of a flux rope's formation. (SDO AIA 131 and 171 difference blended image of flux ropes during CME.) Credit: NASA/Goddard Space Flight Center/SDO ---- On July 18, 2012, a fairly small explosion of light burst off the lower right limb of the sun. Such flares often come with an associated eruption of solar material, known as a coronal mass ejection or CME – but this one did not. Something interesting did happen, however. Magnetic field lines in this area of the sun's atmosphere, the corona, began to twist and kink, generating the hottest solar material – a charged gas called plasma – to trace out the newly-formed slinky shape. The plasma glowed brightly in extreme ultraviolet images from the Atmospheric Imaging Assembly (AIA) aboard NASA’s Solar Dynamics Observatory (SDO) and scientists were able to watch for the first time the very formation of something they had long theorized was at the heart of many eruptive events on the sun: a flux rope. Eight hours later, on July 19, the same region flared again. This time the flux rope's connection to the sun was severed, and the magnetic fields escaped into space, dragging billions of tons of solar material along for the ride -- a classic CME. "Seeing this structure was amazing," says Angelos Vourlidas, a solar scientist at the Naval Research Laboratory in Washington, D.C. "It looks exactly like the cartoon sketches theorists have been drawing of flux ropes since the 1970s. It was a series of figure eights lined up to look like a giant slinky on the sun." To read more about this new discovery go to: 1.usa.gov/14UHsTt

Solar Scientist Confirm Existence of Flux Ropes on the Sun

NASA Image and Video Library

2017-12-08

Caption: This is an image of magnetic loops on the sun, captured by NASA's Solar Dynamics Observatory (SDO). It has been processed to highlight the edges of each loop to make the structure more clear. A series of loops such as this is known as a flux rope, and these lie at the heart of eruptions on the sun known as coronal mass ejections (CMEs.) This is the first time scientists were able to discern the timing of a flux rope's formation. (SDO AIA 131 and 171 difference blended image of flux ropes during CME.) Credit: NASA/Goddard Space Flight Center/SDO ---- On July 18, 2012, a fairly small explosion of light burst off the lower right limb of the sun. Such flares often come with an associated eruption of solar material, known as a coronal mass ejection or CME – but this one did not. Something interesting did happen, however. Magnetic field lines in this area of the sun's atmosphere, the corona, began to twist and kink, generating the hottest solar material – a charged gas called plasma – to trace out the newly-formed slinky shape. The plasma glowed brightly in extreme ultraviolet images from the Atmospheric Imaging Assembly (AIA) aboard NASA’s Solar Dynamics Observatory (SDO) and scientists were able to watch for the first time the very formation of something they had long theorized was at the heart of many eruptive events on the sun: a flux rope. Eight hours later, on July 19, the same region flared again. This time the flux rope's connection to the sun was severed, and the magnetic fields escaped into space, dragging billions of tons of solar material along for the ride -- a classic CME. "Seeing this structure was amazing," says Angelos Vourlidas, a solar scientist at the Naval Research Laboratory in Washington, D.C. "It looks exactly like the cartoon sketches theorists have been drawing of flux ropes since the 1970s. It was a series of figure eights lined up to look like a giant slinky on the sun." To read more about this new discovery go to: 1.usa.gov/14UHsTt

Low Gravity Materials Science Research for Space Exploration

NASA Technical Reports Server (NTRS)

Clinton, R. G., Jr.; Semmes, Edmund B.; Schlagheck, Ronald A.; Bassler, Julie A.; Cook, Mary Beth; Wargo, Michael J.; Sanders, Gerald B.; Marzwell, Neville I.

2004-01-01

On January 14, 2004, the President of the United States announced a new vision for the United States civil space program. The Administrator of the National Aeronautics and Space Administration (NASA) has the responsibility to implement this new vision. The President also created a Presidential Commission 'to obtain recommendations concerning implementation of the new vision for space exploration.' The President's Commission recognized that achieving the exploration objectives would require significant technical innovation, research, and development in focal areas defined as 'enabling technologies.' Among the 17 enabling technologies identified for initial focus were advanced structures; advanced power and propulsion; closed-loop life support and habitability; extravehicular activity system; autonomous systems and robotics; scientific data collection and analysis; biomedical risk mitigation; and planetary in situ resource utilization. The Commission also recommended realignment of NASA Headquarters organizations to support the vision for space exploration. NASA has aggressively responded in its planning to support the vision for space exploration and with the current considerations of the findings and recommendations from the Presidential Commission. This presentation will examine the transformation and realignment activities to support the vision for space exploration that are underway in the microgravity materials science program. The heritage of the microgravity materials science program, in the context of residence within the organizational structure of the Office of Biological and Physical Research, and thematic and sub-discipline based research content areas, will be briefly examined as the starting point for the ongoing transformation. Overviews of future research directions will be presented and the status of organizational restructuring at NASA Headquarters, with respect to influences on the microgravity materials science program, will be discussed. Additional information is included in the original extended abstract.

Piezoelectric and dielectric performance of poled lead zirconate titanate subjected to electric cyclic fatigue

NASA Astrophysics Data System (ADS)

Wang, Hong; Matsunaga, Tadashi; Lin, Hua-Tay; Mottern, Alexander M.

2012-02-01

Poled lead zirconate titanate (PZT) material as a single-layer plate was tested using a piezodilatometer under electric cyclic loading in both unipolar and bipolar modes. Its responses were evaluated using unipolar and bipolar measurements on the same setup. The mechanical strain and charge density loops exhibited various variations when the material was cycled for more than 108 cycles. The various quantities including loop amplitude, hysteresis, switchable polarization, and coercive field were characterized accordingly under the corresponding measurement conditions. At the same time, the offset polarization and bias electric field of the material were observed to be changed and the trend was found to be related to the measurement conditions also. Finally, the piezoelectric and dielectric coefficients were analyzed and their implications for the application of interest have been discussed.

NaK Plugging Meter Design for the Feasibility Test Loops

NASA Technical Reports Server (NTRS)

Pearson, J. Boise; Godfroy, Thomas J.; Reid, Robert S.; Polzin, Kurt A.

2008-01-01

The design and predicted performance of a plugging meter for use in the measurement of NaK impurity levels are presented. The plugging meter is incorporated into a Feasibility Test Loop (FTL), which is a small pumped-NaK loop designed to enable the rapid, small-scale evaluation of techniques such as in situ purification methods and to permit the measurement of bulk material transport effects (not mechanisms) under flow conditions that are representative of a fission surface power reactor. The FTL operates at temperatures similar to those found in a reactor, with a maximum hot side temperature of 900 K and a corresponding cold side temperature of 860 K. In the plugging meter a low flow rate bypass loop is cooled until various impurities (primarily oxides) precipitate out of solution. The temperatures at which these impurities precipitate are indicative of the level of impurities in the NaK. The precipitates incrementally plug a small orifice in the bypass loop, which is detected by monitoring changes in the liquid metal flow rate.

Opto-electronic oscillator: moving toward solutions based on polymer materials

NASA Astrophysics Data System (ADS)

Nguyên, Lâm Duy; Journet, Bernard; Zyss, Joseph

2008-02-01

Optoelectronic oscillators have been studied since many years now, their high spectral purity being one of their most interesting quality for photonics signal processing, communication or radio over fiber systems. One part of the structure is a long fiber optic feedback loop acting as a delay line. Different techniques have been introduced such as multiple loops in order to get very narrow spectral lines and large mode spacing. One of the problems due to long fiber loops is the size and the requirement of temperature control. In order to go toward integrated solutions it is also possible to introduce optical resonators instead of a delay line structure (as for classical electronic oscillators). But such resonators should present very high quality factor. In this paper we demonstrate solutions using resonators based on polymer materials such as PMMA-DCM. Structures such as micro-rings, micro-disks or stadium-shaped resonator have been realized at the laboratory. Quality factor of 6000 have already been achieved leading to an equivalent fiber loop of 19 m for an oscillator at 10 GHz. But it has been already theoretically proved that quality factor greater than one thousand hundred could be obtained. These resonators can be directly implemented with Mach-Zehnder optical modulators based on electro-optic polymer such as PMMA-DR1 leading to integrated solutions. And in the future it should be also possible to add a laser made with polymer material, with a structure as stadium-shape polymer micro-laser. The fully integrated photonic chip is not so far. The last important function to be implemented is the tuning of the oscillation frequency.

Characterisation of radiation damage in W and W-based alloys from 2MeV self-ion near-bulk implantations

DOE PAGES

Yi, Xiaoou; Culham Science Centre, Abingdon; Jenkins, Michael L.; ...

2015-04-21

The displacement damage induced in bulk W and W-5 wt.% Re and W-5 wt.% Ta alloys by 2 MeV W + irradiation to doses 3.3×10 17 - 2.5×10 19 W +/m 2 at temperatures ranging from 300 to750°C has been characterized by transmission electron microscopy. An automated sizing and counting approach based on Image J has been proposed and performed for all irradiation data. In all cases the damage comprised dislocation loops, mostly of interstitial type, with Burgers vectors b = ½<111> (> 60%) and b = <100>. The diameters of loops did not exceed 20 nm, with the majoritymore » being ≤ 6 nm. The loop number density varied between 10 22 and 10 23 loops/m 3 . With increasing irradiation temperature, the loop size distributions shifted towards larger sizes, and there was a substantial decrease in loop number densities. The damage microstructure was less sensitive to dose than to temperature. Under the same irradiation conditions, loop number densities in the alloys were higher than in pure W but loops were smaller. In grains with normals close to z = <001>, loop strings developed in W at temperatures ≥ 500°C and doses ≥ 1.2 dpa, but such strings were not observed in the W-Re or W-Ta alloys. However, in other grain orientations complex structures appeared in all materials and dense dislocation networks formed at higher doses.« less

Orbital loop currents in iron-based superconductors

NASA Astrophysics Data System (ADS)

Klug, Markus; Kang, Jian; Fernandes, Rafael M.; Schmalian, Jörg

2018-04-01

We show that the antiferromagnetic state commonly observed in the phase diagrams of the iron-based superconductors necessarily triggers loop currents characterized by charge transfer between different Fe 3 d orbitals. This effect is rooted on the glide-plane symmetry of these materials and on the existence of an atomic spin-orbit coupling that couples states at the X and Y points of the 1-Fe Brillouin zone. In the particular case in which the magnetic moments are aligned parallel to the magnetic ordering vector direction, which is the moment configuration most commonly found in the iron-based superconductors, these loop currents involve the dx y orbital and either the dy z orbital (if the moments point along the y axis) or the dx z orbitals (if the moments point along the x axis). We show that the two main manifestations of the orbital loop currents are the emergence of magnetic moments in the pnictide/chalcogen site and an orbital-selective band splitting in the magnetically ordered state, both of which could be detected experimentally. Our results highlight the unique intertwining between orbital and spin degrees of freedom in the iron-based superconductors, and reveal the emergence of an unusual correlated phase that may impact the normal state and superconducting properties of these materials.

Direct Observation of Sink-Dependent Defect Evolution in Nanocrystalline Iron under Irradiation

DOE PAGES

El Atwani, Osman; Nathaniel, James; Leff, Asher C.; ...

2017-05-12

Crystal defects generated during irradiation can result in severe changes in morphology and an overall degradation of mechanical properties in a given material. Nanomaterials have been proposed as radiation damage tolerant materials, due to the hypothesis that defect density decreases with grain size refinement due to the increase in grain boundary surface area. The lower defect density should arise from grain boundary-point defect absorption and enhancement of interstitial-vacancy annihilation. In this study, low energy helium ion irradiation on free-standing iron thin films were performed at 573 K. Interstitial loops of a 0 /2 [111] Burgers vector were directly observed asmore » a result of the displacement damage. Loop density trends with grain size demonstrated an increase in the nanocrystalline (<100 nm) regime, but scattered behavior in the transition from the nanocrystalline to the ultra-fine regime (100–500 nm). To examine the validity of such trends, loop density and area for different grains at various irradiation doses were compared and revealed efficient defect absorption in the nanocrystalline grain size regime, but loop coalescence in the ultra-fine grain size regime. Lastly, a relationship between the denuded zone formation, a measure of grain boundary absorption efficiency, grain size, grain boundary type and misorientation angle is determined.« less

Direct Observation of Sink-Dependent Defect Evolution in Nanocrystalline Iron under Irradiation

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

El Atwani, Osman; Nathaniel, James; Leff, Asher C.

Crystal defects generated during irradiation can result in severe changes in morphology and an overall degradation of mechanical properties in a given material. Nanomaterials have been proposed as radiation damage tolerant materials, due to the hypothesis that defect density decreases with grain size refinement due to the increase in grain boundary surface area. The lower defect density should arise from grain boundary-point defect absorption and enhancement of interstitial-vacancy annihilation. In this study, low energy helium ion irradiation on free-standing iron thin films were performed at 573 K. Interstitial loops of a 0 /2 [111] Burgers vector were directly observed asmore » a result of the displacement damage. Loop density trends with grain size demonstrated an increase in the nanocrystalline (<100 nm) regime, but scattered behavior in the transition from the nanocrystalline to the ultra-fine regime (100–500 nm). To examine the validity of such trends, loop density and area for different grains at various irradiation doses were compared and revealed efficient defect absorption in the nanocrystalline grain size regime, but loop coalescence in the ultra-fine grain size regime. Lastly, a relationship between the denuded zone formation, a measure of grain boundary absorption efficiency, grain size, grain boundary type and misorientation angle is determined.« less

THE CONTRACTION OF OVERLYING CORONAL LOOP AND THE ROTATING MOTION OF A SIGMOID FILAMENT DURING ITS ERUPTION

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

Yan, X. L.; Qu, Z. Q.; Xue, Z. K.

We present an observation of overlying coronal loop contraction and rotating motion of the sigmoid filament during its eruption on 2012 May 22 observed by the Solar Dynamics Observatory (SDO). Our results show that the twist can be transported into the filament from the lower atmosphere to the higher atmosphere. The successive contraction of the coronal loops was due to a suddenly reduced magnetic pressure underneath the filament, which was caused by the rising of the filament. Before the sigmoid filament eruption, there was a counterclockwise flow in the photosphere at the right feet of the filament and the contractionmore » loops and a convergence flow at the left foot of the filament. The hot and cool materials have inverse motion along the filament before the filament eruption. Moreover, two coronal loops overlying the filament first experienced brightening, expansion, and contraction successively. At the beginning of the rising and rotation of the left part of the filament, the second coronal loop exhibited rapid contraction. The top of the second coronal loop also showed counterclockwise rotation during the contraction process. After the contraction of the second loop, the left part of the filament rotated counterclockwise and expanded toward the right of NOAA AR 11485. During the filament expansion, the right part of the filament also exhibited counterclockwise rotation like a tornado.« less

The Contraction of Overlying Coronal Loop and the Rotating Motion of a Sigmoid Filament during Its Eruption

NASA Astrophysics Data System (ADS)

Yan, X. L.; Pan, G. M.; Liu, J. H.; Qu, Z. Q.; Xue, Z. K.; Deng, L. H.; Ma, L.; Kong, D. F.

2013-06-01

We present an observation of overlying coronal loop contraction and rotating motion of the sigmoid filament during its eruption on 2012 May 22 observed by the Solar Dynamics Observatory (SDO). Our results show that the twist can be transported into the filament from the lower atmosphere to the higher atmosphere. The successive contraction of the coronal loops was due to a suddenly reduced magnetic pressure underneath the filament, which was caused by the rising of the filament. Before the sigmoid filament eruption, there was a counterclockwise flow in the photosphere at the right feet of the filament and the contraction loops and a convergence flow at the left foot of the filament. The hot and cool materials have inverse motion along the filament before the filament eruption. Moreover, two coronal loops overlying the filament first experienced brightening, expansion, and contraction successively. At the beginning of the rising and rotation of the left part of the filament, the second coronal loop exhibited rapid contraction. The top of the second coronal loop also showed counterclockwise rotation during the contraction process. After the contraction of the second loop, the left part of the filament rotated counterclockwise and expanded toward the right of NOAA AR 11485. During the filament expansion, the right part of the filament also exhibited counterclockwise rotation like a tornado.

Component and Technology Development for Advanced Liquid Metal Reactors

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

Anderson, Mark

2017-01-30

The following report details the significant developments to Sodium Fast Reactor (SFR) technologies made throughout the course of this funding. This report will begin with an overview of the sodium loop and the improvements made over the course of this research to make it a more advanced and capable facility. These improvements have much to do with oxygen control and diagnostics. Thus a detailed report of advancements with respect to the cold trap, plugging meter, vanadium equilibration loop, and electrochemical oxygen sensor is included. Further analysis of the university’s moving magnet pump was performed and included in a section ofmore » this report. A continuous electrical resistance based level sensor was built and tested in the sodium with favorable results. Materials testing was done on diffusion bonded samples of metal and the results are presented here as well. A significant portion of this work went into the development of optical fiber temperature sensors which could be deployed in an SFR environment. Thus, a section of this report presents the work done to develop an encapsulation method for these fibers inside of a stainless steel capillary tube. High temperature testing was then done on the optical fiber ex situ in a furnace. Thermal response time was also explored with the optical fiber temperature sensors. Finally these optical fibers were deployed successfully in a sodium environment for data acquisition. As a test of the sodium deployable optical fiber temperature sensors they were installed in a sub-loop of the sodium facility which was constructed to promote the thermal striping effect in sodium. The optical fibers performed exceptionally well, yielding unprecedented 2 dimensional temperature profiles with good temporal resolution. Finally, this thermal striping loop was used to perform cross correlation velocimetry successfully over a wide range of flow rates.« less

Metrics for Systems Thinking in the Human Dimension

DTIC Science & Technology

2016-11-01

corpora of documents. 2 Methodology Overview We present a human-in-the- loop methodology that assists researchers and analysts by characterizing...supervised learning methods. Building on this foundation, we present an unsupervised, human-in-the- loop methodology that utilizes topic models to...the definition of strong systems thinking and in the interpretation of topics, but this is what makes the human-in-the- loop methodology so effective

Method and Apparatus for Producing a Substrate with Low Secondary Electron Emissions

NASA Technical Reports Server (NTRS)

Jensen, Kenneth A. (Inventor); Curren, Arthur N. (Inventor); Roman, Robert F. (Inventor)

1998-01-01

The present invention is directed to a method and apparatus for producing a highly-textured surface on a copper substrate with only extremely small amounts of texture-inducing seeding of masking material. The texture-inducing seeding material is delivered to the copper substrate electrically switching the seeding material in and out of a circuit loop.

Development of closed loop roll control for magnetic balance systems

NASA Technical Reports Server (NTRS)

Covert, E. E.; Haldeman, C. W.; Ramohalli, G.; Way, P.

1982-01-01

This research was undertaken with the goal of demonstrating closed loop control of the roll degree of freedom on the NASA prototype magnetic suspension and balance system at the MIT Aerophysics Laboratory, thus, showing feasibility for a roll control system for any large magnetic balance system which might be built in the future. During the research under this grant, study was directed toward the several areas of torque generation, position sensing, model construction and control system design. These effects were then integrated to produce successful closed loop operation of the analogue roll control system. This experience indicated the desirability of microprocessor control for the angular degrees of freedom.

The insertion of human dynamics models in the flight control loops of V/STOL research aircraft. Appendix 2: The optimal control model of a pilot in V/STOL aircraft control loops

NASA Technical Reports Server (NTRS)

Zipf, Mark E.

1989-01-01

An overview is presented of research work focussed on the design and insertion of classical models of human pilot dynamics within the flight control loops of V/STOL aircraft. The pilots were designed and configured for use in integrated control system research and design. The models of human behavior that were considered are: McRuer-Krendel (a single variable transfer function model); and Optimal Control Model (a multi-variable approach based on optimal control and stochastic estimation theory). These models attempt to predict human control response characteristics when confronted with compensatory tracking and state regulation tasks. An overview, mathematical description, and discussion of predictive limitations of the pilot models is presented. Design strategies and closed loop insertion configurations are introduced and considered for various flight control scenarios. Models of aircraft dynamics (both transfer function and state space based) are developed and discussed for their use in pilot design and application. Pilot design and insertion are illustrated for various flight control objectives. Results of pilot insertion within the control loops of two V/STOL research aricraft (Sikorski Black Hawk UH-60A, McDonnell Douglas Harrier II AV-8B) are presented and compared against actual pilot flight data. Conclusions are reached on the ability of the pilot models to adequately predict human behavior when confronted with similar control objectives.

The Aircraft Morphing Program

NASA Technical Reports Server (NTRS)

Wlezien, R. W.; Horner, G. C.; McGowan, A. R.; Padula, S. L.; Scott, M. A.; Silcox, R. J.; Simpson, J. O.

1998-01-01

In the last decade smart technologies have become enablers that cut across traditional boundaries in materials science and engineering. Here we define smart to mean embedded actuation, sensing, and control logic in a tightly coupled feedback loop. While multiple successes have been achieved in the laboratory, we have yet to see the general applicability of smart devices to real aircraft systems. The NASA Aircraft Morphing program is an attempt to couple research across a wide range of disciplines to integrate smart technologies into high payoff aircraft applications. The program bridges research in seven individual disciplines and combines the effort into activities in three primary program thrusts. System studies are used to assess the highest- payoff program objectives, and specific research activities are defined to address the technologies required for development of smart aircraft systems. In this paper we address the overall program goals and programmatic structure, and discuss the challenges associated with bringing the technologies to fruition.

Transcription of telomeric DNA leads to high levels of homologous recombination and t-loops.

PubMed

Kar, Anirban; Willcox, Smaranda; Griffith, Jack D

2016-11-02

The formation of DNA loops at chromosome ends (t-loops) and the transcription of telomeres producing G-rich RNA (TERRA) represent two central features of telomeres. To explore a possible link between them we employed artificial human telomeres containing long arrays of TTAGGG repeats flanked by the T7 or T3 promoters. Transcription of these DNAs generates a high frequency of t-loops within individual molecules and homologous recombination events between different DNAs at their telomeric sequences. T-loop formation does not require a single strand overhang, arguing that both terminal strands insert into the preceding duplex. The loops are very stable and some RNase H resistant TERRA remains at the t-loop, likely adding to their stability. Transcription of DNAs containing TTAGTG or TGAGTG repeats showed greatly reduced loop formation. While in the cell multiple pathways may lead to t-loop formation, the pathway revealed here does not depend on the shelterins but rather on the unique character of telomeric DNA when it is opened for transcription. Hence, telomeric sequences may have evolved to facilitate their ability to loop back on themselves. © The Author(s) 2016. Published by Oxford University Press on behalf of Nucleic Acids Research.

Selected Analytical Methods for Environmental Remediation ...

EPA Pesticide Factsheets

The US Environmental Protection Agency’s Office of Research and Development (ORD) conducts cutting-edge research that provides the underpinning of science and technology for public health and environmental policies and decisions made by federal, state and other governmental organizations. ORD’s six research programs identify the pressing research needs with input from EPA offices and stakeholders. Research is conducted by ORD’s 3 labs, 4 centers, and 2 offices located in 14 facilities. The EPA booth at APHL will have several resources available to attendees, mostly in the form of print materials, that showcase our research labs, case studies of research activities, and descriptions of specific research projects. The Selected Analytical Methods for Environmental Remediation and Recovery (SAM), a library of selected methods that are helping to increase the nation's laboratory capacity to support large-scale emergency response operations, will be demoed by EPA scientists at the APHL Experience booth in the Exhibit Hall on Tuesday during the morning break. Please come to the EPA booth #309 for more information! To be on a loop at our ORD booth demo during APHL.

Dirac node arcs in PtSn 4

DOE PAGES

Wu, Yun; Wang, Lin -Lin; Mun, Eundeok; ...

2016-04-04

In topological quantum materials 1,2,3 the conduction and valence bands are connected at points or along lines in the momentum space. A number of studies have demonstrated that several materials are indeed Dirac/Weyl semimetals 4,5,6,7,8. However, there is still no experimental confirmation of materials with line nodes, in which the Dirac nodes form closed loops in the momentum space 2,3. Here we report the discovery of a novel topological structure—Dirac node arcs—in the ultrahigh magnetoresistive material PtSn 4 using laser-based angle-resolved photoemission spectroscopy data and density functional theory calculations. Unlike the closed loops of line nodes, the Dirac node arcmore » structure arises owing to the surface states and resembles the Dirac dispersion in graphene that is extended along a short line in the momentum space. Here, we propose that this reported Dirac node arc structure is a novel topological state that provides an exciting platform for studying the exotic properties of Dirac fermions.« less

Comparison of high temperature, high frequency core loss and dynamic B-H loops of a 2V-49Fe-49Co and a grain oriented 3Si-Fe alloy

NASA Technical Reports Server (NTRS)

Wieserman, W. R.; Schwarze, G. E.; Niedra, J. M.

1992-01-01

The design of power magnetic components such as transformers, inductors, motors, and generators, requires specific knowledge about the magnetic and electrical characteristics of the magnetic materials used in these components. Limited experimental data exists that characterizes the performance of soft magnetic materials for the combined conditions of high temperature and high frequency over a wide flux density range. An experimental investigation of a 2V-49-Fe-49Co (Supermendur) and a grain oriented 3 Si-Fe (Magnesil) alloy was conducted over the temperature range of 23 to 300 C and frequency range of 0.1 to 10 kHz. The effects of temperature, frequency, and maximum flux density on the core loss and dynamic B-H loops for sinusoidal voltage excitation conditions are examined for each of these materials. A comparison of the core loss of these two materials is also made over the temperature and frequency range investigated.

Abdomen after a Puestow procedure: postoperative CT appearance, complications, and potential pitfalls.

PubMed

Freed, K S; Paulson, E K; Frederick, M G; Keogan, M T; Pappas, T N

1997-06-01

To evaluate the postoperative computed tomographic (CT) appearance, complications, and potential pitfalls after a Puestow procedure (lateral side-to-side pancreaticojejunostomy). Forty CT examinations were performed after the Puestow procedure in 20 patients. Images were retrospectively reviewed by three radiologists. The pancreaticojejunal anastomosis was identified at 30 examinations and was immediately anterior to the pancreatic body or tail. The anastomosis contained fluid or gas on 11 scans and oral contrast material on four scans. On 15 scans, the anastomosis appeared as collapsed bowel without gas, fluid, or oral contrast material. The Roux-en-Y loop was identified on 28 (70%) scans and contained fluid or gas on 16 scans and oral contrast material on six scans. The Roux-en-Y loop appeared as collapsed bowel on six scans. When the anastomosis or Roux-en-Y loop contained fluid and gas, the appearance mimicked that of a pancreatic or parapancreatic abscess. Peripancreatic stranding was present on 28 scans and was due to either ongoing pancreatitis or postoperative change. Complications included 15 transient fluid collections, three abscesses, four pseudocysts, one hematoma, and one small-bowel and Roux-en-Y obstruction. Knowledge of the anatomy after a Puestow procedure is essential for accurate interpretation of CT scans.

Localizing softness and stress along loops in 3D topological metamaterials

NASA Astrophysics Data System (ADS)

Baardink, Guido; Souslov, Anton; Paulose, Jayson; Vitelli, Vincenzo

2018-01-01

Topological states can be used to control the mechanical properties of a material along an edge or around a localized defect. The rigidity of elastic networks is characterized by a topological invariant called the polarization; materials with a well-defined uniform polarization display a dramatic range of edge softness depending on the orientation of the polarization relative to the terminating surface. However, in all 3D mechanical metamaterials proposed to date, the topological modes are mixed with bulk soft modes, which organize themselves in Weyl loops. Here, we report the design of a 3D topological metamaterial without Weyl lines and with a uniform polarization that leads to an asymmetry between the number of soft modes on opposing surfaces. We then use this construction to localize topological soft modes in interior regions of the material by including defect lines—dislocation loops—that are unique to three dimensions. We derive a general formula that relates the difference in the number of soft modes and states of self-stress localized along the dislocation loop to the handedness of the vector triad formed by the lattice polarization, Burgers vector, and dislocation-line direction. Our findings suggest a strategy for preprogramming failure and softness localized along lines in 3D, while avoiding extended soft Weyl modes.

Self sufficient wireless transmitter powered by foot-pumped urine operating wearable MFC.

PubMed

Taghavi, M; Stinchcombe, A; Greenman, J; Mattoli, V; Beccai, L; Mazzolai, B; Melhuish, C; Ieropoulos, I A

2015-12-10

The first self-sufficient system, powered by a wearable energy generator based on microbial fuel cell (MFC) technology is introduced. MFCs made from compliant material were developed in the frame of a pair of socks, which was fed by urine via a manual gaiting pump. The simple and single loop cardiovascular fish circulatory system was used as the inspiration for the design of the manual pump. A wireless programmable communication module, engineered to operate within the range of the generated electricity, was employed, which opens a new avenue for research in the utilisation of waste products for powering portable as well as wearable electronics.

Human-in-the-loop development of soft wearable robots

NASA Astrophysics Data System (ADS)

Walsh, Conor

2018-06-01

The field of soft wearable robotics offers the opportunity to wear robots like clothes to assist the movement of specific body parts or to endow the body with functionalities. Collaborative efforts of materials, apparel and robotics science have already led to the development of wearable technologies for physical therapy. Optimizing the human-robot system by human-in-the-loop approaches will pave the way for personalized soft wearable robots for a variety of applications.

MINI-FILAMENT ERUPTION AS THE INITIATION OF A JET ALONG CORONAL LOOPS

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

Hong, Junchao; Jiang, Yunchun; Yang, Jiayan

Minifilament eruptions (MFEs) and coronal jets are different types of solar small-scale explosive events. We report an MFE observed at the New Vacuum Solar Telescope (NVST). As seen in the NVST H α images, during the rising phase, the minifilament erupts outward orthogonally to its length, accompanied with a flare-like brightening at the bottom. Afterward, dark materials are found to possibly extend along the axis of the expanded filament body. The MFE is analogous to large filament eruptions. However, a simultaneous observation of the Solar Dynamics Observatory shows that a jet is initiated and flows out along nearby coronal loopsmore » during the rising phase of the MFE. Meanwhile, small hot loops, which connect the original eruptive site of the minifilament to the footpoints of the coronal loops, are formed successively. A differential emission measure analysis demonstrates that, on the top of the new small loops, a hot cusp structure exists. We conjecture that the magnetic fields of the MFE interact with magnetic fields of the coronal loops. This interaction is interpreted as magnetic reconnection that produces the jet and the small hot loops.« less

Mechanical characteristics and comparisons of cerclage wires: introduction of the double-wrap and loop/twist tying methods.

PubMed

Roe, S C

1997-01-01

Evaluate the mechanical properties of twist, loop, double loop, double-wrap and loop/twist cerclage. The initial tension generated by 18 cerclage of each type was determined using a materials testing machine after tying around a testing jig. Six wires from each type were distracted and the initial stiffness and yield load were determined. Yield behavior was further investigated in six wires of each type by determining the load required to reduce cerclage tension below 30 Newton (N) following and incremental (50 N) stepwise load and unload regimen. The amount of collapse of the simulated bone fragments that resulted in the reduction of initial tension to 30 N was measured for the final six wires of each group. Data were analyzed by analysis of variance and a multiple comparison test. Twist type cerclage generated less tension than loop-type cerclage. The yield load of these two types was similar. Double-loop and double-wrap cerclage generated superior tension and resisted a greater load before loosening. Loop/twist cerclage had an intermediate initial tension but had the greatest resistance to loading. In the collapse test, the greater the initial tension, the more collapse could occur before the wire was loose. For all types of cerclage wire fixation, a reduction of diameter of the testing jig of more than 1% caused loosening. Double-loop and double-wrap cerclage provide greater compression of fragments and resist loads associated with weight-bearing better than the twist and loop methods. Loop/twist cerclage may have advantages because of their superior resistance to loading. All cerclage will loosen if fracture fragments collapse.

OUTER LOOP LANDFILL CASE STUDY

EPA Science Inventory

This presentation will describe the interim data reaulting from a CRADA between USEPA and Waste Management, Inc. at the outer Loop Landfill Bioreactor research project located in Louisville, KY. Recently updated data will be presented covering landfill solids, gas being collecte...

Evaluation of dual-loop data accuracy using video ground truth data

DOT National Transportation Integrated Search

2002-01-01

Washington State Department of Transportation (WSDOT) initiated a : research project entitled Monitoring Freight on Puget Sound Freeways in September : 1999. Dual-loop data from the Seattle area freeway system were selected as the main data : s...

Topological Interaction by Entangled DNA Loops

NASA Astrophysics Data System (ADS)

Feng, Lang; Sha, Ruojie; Seeman, Nadrian. C.; Chaikin, Paul. M.

2012-11-01

We have discovered a new type of interaction between micro- or nanoscale particles that results from the entanglement of strands attached to their surfaces. Self-complementary DNA single strands on a particle can hybridize to form loops. A similar proximal particle can have its loops catenate with those of the first. Unlike conventional thermodynamic interparticle interactions, the catenation interaction is strongly history and protocol dependent, allowing for nonequilibrium particle assembly. The interactions can be controlled by an interesting combination of forces, temperature, light sensitive cross-linking and enzymatic unwinding of the topological links. This novel topological interaction may lead to new materials and phenomena such as particles strung on necklaces, confined motions on designed contours and surfaces, and colloidal Olympic gels.

A simplified technique for a totally diverting transverse loop colostomy and distal irrigation.

PubMed

Rose, D; Koniges, F; Frazier, T G

1985-12-01

This technique of totally diverting loop colostomy may be performed as an independent procedure or with exploratory laparotomy and surgical treatment on the distal part of the colon. Either a transverse or sigmoid loop colostomy can be used for diversion without the risk of fecal contamination of the peritoneal cavity, particularly when working with unprepared intestine. When distal irrigation is desired to purge the intestine of fecal material, either intraoperatively or as part of a subsequent intestinal preparation, it can easily be accomplished by placing an irrigating catheter distal to the staple line. In addition, the use of a small rubber suspension bar facilitates application of standard colostomy appliances for the stoma.

Neutron tomography of axially symmetric objects using 14 MeV neutrons from a portable neutron generator

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

Andersson, P., E-mail: peter.andersson@physics.uu.se; Andersson-Sunden, E.; Sjöstrand, H.

2014-08-01

In nuclear boiling water reactor cores, the distribution of water and steam (void) is essential for both safety and efficiency reasons. In order to enhance predictive capabilities, void distribution assessment is performed in two-phase test-loops under reactor-relevant conditions. This article proposes the novel technique of fast-neutron tomography using a portable deuterium-tritium neutron generator to determine the time-averaged void distribution in these loops. Fast neutrons have the advantage of high transmission through the metallic structures and pipes typically concealing a thermal-hydraulic test loop, while still being fairly sensitive to the water/void content. However, commercially available fast-neutron generators also have the disadvantagemore » of a relatively low yield and fast-neutron detection also suffers from relatively low detection efficiency. Fortunately, some loops are axially symmetric, a property which can be exploited to reduce the amount of data needed for tomographic measurement, thus limiting the interrogation time needed. In this article, three axially symmetric test objects depicting a thermal-hydraulic test loop have been examined; steel pipes with outer diameter 24 mm, thickness 1.5 mm, and with three different distributions of the plastic material POM inside the pipes. Data recorded with the FANTOM fast-neutron tomography instrument have been used to perform tomographic reconstructions to assess their radial material distribution. Here, a dedicated tomographic algorithm that exploits the symmetry of these objects has been applied, which is described in the paper. Results are demonstrated in 20 rixel (radial pixel) reconstructions of the interior constitution and 2D visualization of the pipe interior is demonstrated. The local POM attenuation coefficients in the rixels were measured with errors (RMS) of 0.025, 0.020, and 0.022 cm{sup −1}, solid POM attenuation coefficient. The accuracy and precision is high enough to provide a useful indication on the flow mode, and a visualization of the radial material distribution can be obtained. A benefit of this system is its potential to be mounted at any axial height of a two-phase test section without requirements for pre-fabricated entrances or windows. This could mean a significant increase in flexibility of the void distribution assessment capability at many existing two-phase test loops.« less

Neutron tomography of axially symmetric objects using 14 MeV neutrons from a portable neutron generator.

PubMed

Andersson, P; Andersson-Sunden, E; Sjöstrand, H; Jacobsson-Svärd, S

2014-08-01

In nuclear boiling water reactor cores, the distribution of water and steam (void) is essential for both safety and efficiency reasons. In order to enhance predictive capabilities, void distribution assessment is performed in two-phase test-loops under reactor-relevant conditions. This article proposes the novel technique of fast-neutron tomography using a portable deuterium-tritium neutron generator to determine the time-averaged void distribution in these loops. Fast neutrons have the advantage of high transmission through the metallic structures and pipes typically concealing a thermal-hydraulic test loop, while still being fairly sensitive to the water/void content. However, commercially available fast-neutron generators also have the disadvantage of a relatively low yield and fast-neutron detection also suffers from relatively low detection efficiency. Fortunately, some loops are axially symmetric, a property which can be exploited to reduce the amount of data needed for tomographic measurement, thus limiting the interrogation time needed. In this article, three axially symmetric test objects depicting a thermal-hydraulic test loop have been examined; steel pipes with outer diameter 24 mm, thickness 1.5 mm, and with three different distributions of the plastic material POM inside the pipes. Data recorded with the FANTOM fast-neutron tomography instrument have been used to perform tomographic reconstructions to assess their radial material distribution. Here, a dedicated tomographic algorithm that exploits the symmetry of these objects has been applied, which is described in the paper. Results are demonstrated in 20 rixel (radial pixel) reconstructions of the interior constitution and 2D visualization of the pipe interior is demonstrated. The local POM attenuation coefficients in the rixels were measured with errors (RMS) of 0.025, 0.020, and 0.022 cm(-1), solid POM attenuation coefficient. The accuracy and precision is high enough to provide a useful indication on the flow mode, and a visualization of the radial material distribution can be obtained. A benefit of this system is its potential to be mounted at any axial height of a two-phase test section without requirements for pre-fabricated entrances or windows. This could mean a significant increase in flexibility of the void distribution assessment capability at many existing two-phase test loops.

Structure and dynamics of coronal plasmas

NASA Technical Reports Server (NTRS)

Golub, Leon

1995-01-01

The Normal Incidence X-ray Telescope (NIXT) obtained a unique set of high resolution full disk solar images which were exposed simultaneously by X-rays in a passband at 63.5 A and by visible light. The perfect alignment of a photospheric visible light image with a coronal X-ray image enables us to present observations of X-ray intensity vs an accurately determined height above the visible limb. The height at which the observed X-ray intensity peak varies from 4000 km in active regions to 9000 km in quiet regions of the sun. The interpretation of the observations stems from the previously established fact that, for the coronal loops, emission in the NIXT bandpass peaks sharply just above the footpoints. Because there is not a sharp peak in the observed X-ray intensity vs off limb height, we conclude that the loop footpoints, when viewed at the limb, are obscured by absorption in chromospheric material along the line of sight. We calculate the X-ray intensity vs height predicted by a number of different idealizations of the solar atmosphere, and we compare these calculations with the observed X-ray intensity vs height. The calculations use existing coronal and chromospheric models. In order for the calculations to reproduce the observed off limb X-ray intensities, we are forced to assume an atmosphere in which the footpoints of coronal loops are interspersed along the line of sight with cooler chromospheric material extending to heights well above the loop footpoints. We argue that the absorption coefficient for NIXT X-rays by chromospheric material is roughly proportional to the neutral hydrogen density, and we estimate an average neutral hydrogen density and scale height implied by the data.

Rare Presentation of a Primary Cutaneous well Differentiated Liposarcoma

DTIC Science & Technology

2018-02-16

Roberts, Capt Jared 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) 59th Clinical Research Division 1100 Willford Hall Loop, Bldg 4430 JBSA-Lackland...TX 78236-9908 210-292-7141 9. SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES) 59th Clinical Research Division 1100 Willford Hall Loop, Bldg...been proposed to aid in identifying lipoblasts. Lipoblasts should have a hyperchromatic indented or sharply scalloped nucleus, a lipid -rich droplets

Aircraft flight test trajectory control

NASA Technical Reports Server (NTRS)

Menon, P. K. A.; Walker, R. A.

1988-01-01

Two control law design techniques are compared and the performance of the resulting controllers evaluated. The design requirement is for a flight test trajectory controller (FTTC) capable of closed-loop, outer-loop control of an F-15 aircraft performing high-quality research flight test maneuvers. The maneuver modeling, linearization, and design methodologies utilized in this research, are detailed. The results of applying these FTTCs to a nonlinear F-15 simulation are presented.

Wireless Power Transfer for Space Applications

NASA Technical Reports Server (NTRS)

Ramos, Gabriel Vazquez; Yuan, Jiann-Shiun

2011-01-01

This paper introduces an implementation for magnetic resonance wireless power transfer for space applications. The analysis includes an equivalent impedance study, loop material characterization, source/load resonance coupling technique, and system response behavior due to loads variability. System characterization is accomplished by executing circuit design from analytical equations and simulations using Matlab and SPICE. The theory was validated by a combination of different experiments that includes loop material consideration, resonance coupling circuits considerations, electric loads considerations and a small scale proof-of-concept prototype. Experiment results shows successful wireless power transfer for all the cases studied. The prototype provided about 4.5 W of power to the load at a separation of -5 cm from the source using a power amplifier rated for 7 W.

Application of a Loop-Type Laboratory Biofilm Reactor to the Evaluation of Biofilm for Some Metallic Materials and Polymers such as Urinary Stents and Catheters

PubMed Central

Kanematsu, Hideyuki; Kudara, Hikonaru; Kanesaki, Shun; Kogo, Takeshi; Ikegai, Hajime; Ogawa, Akiko; Hirai, Nobumitsu

2016-01-01

A laboratory biofilm reactor (LBR) was modified to a new loop-type closed system in order to evaluate novel stents and catheter materials using 3D optical microscopy and Raman spectroscopy. Two metallic specimens, pure nickel and cupronickel (80% Cu-20% Ni), along with two polymers, silicone and polyurethane, were chosen as examples to ratify the system. Each set of specimens was assigned to the LBR using either tap water or an NB (Nutrient broth based on peptone from animal foods and beef extract mainly)—cultured solution with E-coli formed over 48–72 h. The specimens were then analyzed using Raman Spectroscopy. 3D optical microscopy was employed to corroborate the Raman Spectroscopy results for only the metallic specimens since the inherent roughness of the polymer specimens made such measurements difficult. The findings suggest that the closed loop-type LBR together with Raman spectroscopy analysis is a useful method for evaluating biomaterials as a potential urinary system. PMID:28773945

Scanning SQUID sampler with 40-ps time resolution

NASA Astrophysics Data System (ADS)

Cui, Zheng; Kirtley, John R.; Wang, Yihua; Kratz, Philip A.; Rosenberg, Aaron J.; Watson, Christopher A.; Gibson, Gerald W.; Ketchen, Mark B.; Moler, Kathryn. A.

2017-08-01

Scanning Superconducting QUantum Interference Device (SQUID) microscopy provides valuable information about magnetic properties of materials and devices. The magnetic flux response of the SQUID is often linearized with a flux-locked feedback loop, which limits the response time to microseconds or longer. In this work, we present the design, fabrication, and characterization of a novel scanning SQUID sampler with a 40-ps time resolution and linearized response to periodically triggered signals. Other design features include a micron-scale pickup loop for the detection of local magnetic flux, a field coil to apply a local magnetic field to the sample, and a modulation coil to operate the SQUID sampler in a flux-locked loop to linearize the flux response. The entire sampler device is fabricated on a 2 mm × 2 mm chip and can be scanned over macroscopic planar samples. The flux noise at 4.2 K with 100 kHz repetition rate and 1 s of averaging is of order 1 mΦ0. This SQUID sampler will be useful for imaging dynamics in magnetic and superconducting materials and devices.

Scanning SQUID sampler with 40-ps time resolution.

PubMed

Cui, Zheng; Kirtley, John R; Wang, Yihua; Kratz, Philip A; Rosenberg, Aaron J; Watson, Christopher A; Gibson, Gerald W; Ketchen, Mark B; Moler, Kathryn A

2017-08-01

Scanning Superconducting QUantum Interference Device (SQUID) microscopy provides valuable information about magnetic properties of materials and devices. The magnetic flux response of the SQUID is often linearized with a flux-locked feedback loop, which limits the response time to microseconds or longer. In this work, we present the design, fabrication, and characterization of a novel scanning SQUID sampler with a 40-ps time resolution and linearized response to periodically triggered signals. Other design features include a micron-scale pickup loop for the detection of local magnetic flux, a field coil to apply a local magnetic field to the sample, and a modulation coil to operate the SQUID sampler in a flux-locked loop to linearize the flux response. The entire sampler device is fabricated on a 2 mm × 2 mm chip and can be scanned over macroscopic planar samples. The flux noise at 4.2 K with 100 kHz repetition rate and 1 s of averaging is of order 1 mΦ 0 . This SQUID sampler will be useful for imaging dynamics in magnetic and superconducting materials and devices.

A simple model of hysteresis behavior using spreadsheet analysis

NASA Astrophysics Data System (ADS)

Ehrmann, A.; Blachowicz, T.

2015-01-01

Hysteresis loops occur in many scientific and technical problems, especially as field dependent magnetization of ferromagnetic materials, but also as stress-strain-curves of materials measured by tensile tests including thermal effects, liquid-solid phase transitions, in cell biology or economics. While several mathematical models exist which aim to calculate hysteresis energies and other parameters, here we offer a simple model for a general hysteretic system, showing different hysteresis loops depending on the defined parameters. The calculation which is based on basic spreadsheet analysis plus an easy macro code can be used by students to understand how these systems work and how the parameters influence the reactions of the system on an external field. Importantly, in the step-by-step mode, each change of the system state, compared to the last step, becomes visible. The simple program can be developed further by several changes and additions, enabling the building of a tool which is capable of answering real physical questions in the broad field of magnetism as well as in other scientific areas, in which similar hysteresis loops occur.

Phase-field Model for Interstitial Loop Growth Kinetics and Thermodynamic and Kinetic Models of Irradiated Fe-Cr Alloys

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

Li, Yulan; Hu, Shenyang Y.; Sun, Xin

2011-06-15

Microstructure evolution kinetics in irradiated materials has strongly spatial correlation. For example, void and second phases prefer to nucleate and grow at pre-existing defects such as dislocations, grain boundaries, and cracks. Inhomogeneous microstructure evolution results in inhomogeneity of microstructure and thermo-mechanical properties. Therefore, the simulation capability for predicting three dimensional (3-D) microstructure evolution kinetics and its subsequent impact on material properties and performance is crucial for scientific design of advanced nuclear materials and optimal operation conditions in order to reduce uncertainty in operational and safety margins. Very recently the meso-scale phase-field (PF) method has been used to predict gas bubblemore » evolution, void swelling, void lattice formation and void migration in irradiated materials,. Although most results of phase-field simulations are qualitative due to the lake of accurate thermodynamic and kinetic properties of defects, possible missing of important kinetic properties and processes, and the capability of current codes and computers for large time and length scale modeling, the simulations demonstrate that PF method is a promising simulation tool for predicting 3-D heterogeneous microstructure and property evolution, and providing microstructure evolution kinetics for higher scale level simulations of microstructure and property evolution such as mean field methods. This report consists of two parts. In part I, we will present a new phase-field model for predicting interstitial loop growth kinetics in irradiated materials. The effect of defect (vacancy/interstitial) generation, diffusion and recombination, sink strength, long-range elastic interaction, inhomogeneous and anisotropic mobility on microstructure evolution kinetics is taken into account in the model. The model is used to study the effect of elastic interaction on interstitial loop growth kinetics, the interstitial flux, and sink strength of interstitial loop for interstitials. In part II, we present a generic phase field model and discuss the thermodynamic and kinetic properties in phase-field models including the reaction kinetics of radiation defects and local free energy of irradiated materials. In particular, a two-sublattice thermodynamic model is suggested to describe the local free energy of alloys with irradiated defects. Fe-Cr alloy is taken as an example to explain the required thermodynamic and kinetic properties for quantitative phase-field modeling. Finally the great challenges in phase-field modeling will be discussed.« less

A Dynamic Model of Sustainment Investment

DTIC Science & Technology

2015-02-01

Sustainment System Dynamics Model 11 Figure 7: Core Structure of Sustainment Work 12 Figure 8: Bandwagon Effect Loop 13 Figure 9: Limits to Growth Loop 14...Dynamics Model sustainment capacity sustainment performance gap Bandwagon Effect R1 Limits to Growth B1 S Work Smarter B3 Work Bigger B2 desired...which is of concern primarily when using the model as a vehicle for research. Figure 8 depicts a reinforcing loop called the “ Bandwagon Effect

Stretchable Random Lasers with Tunable Coherent Loops.

PubMed

Sun, Tzu-Min; Wang, Cih-Su; Liao, Chi-Shiun; Lin, Shih-Yao; Perumal, Packiyaraj; Chiang, Chia-Wei; Chen, Yang-Fang

2015-12-22

Stretchability represents a key feature for the emerging world of realistic applications in areas, including wearable gadgets, health monitors, and robotic skins. Many optical and electronic technologies that can respond to large strain deformations have been developed. Laser plays a very important role in our daily life since it was discovered, which is highly desirable for the development of stretchable devices. Herein, stretchable random lasers with tunable coherent loops are designed, fabricated, and demonstrated. To illustrate our working principle, the stretchable random laser is made possible by transferring unique ZnO nanobrushes on top of polydimethylsiloxane (PDMS) elastomer substrate. Apart from the traditional gain material of ZnO nanorods, ZnO nanobrushes were used as optical gain materials so they can serve as scattering centers and provide the Fabry-Perot cavity to enhance laser action. The stretchable PDMS substrate gives the degree of freedom to mechanically tune the coherent loops of the random laser action by changing the density of ZnO nanobrushes. It is found that the number of laser modes increases with increasing external strain applied on the PDMS substrate due to the enhanced possibility for the formation of coherent loops. The device can be stretched by up to 30% strain and subjected to more than 100 cycles without loss in laser action. The result shows a major advance for the further development of man-made smart stretchable devices.

Organic Solar Cells beyond One Pair of Donor-Acceptor: Ternary Blends and More.

PubMed

Yang, Liqiang; Yan, Liang; You, Wei

2013-06-06

Ternary solar cells enjoy both an increased light absorption width, and an easy fabrication process associated with their simple structures. Significant progress has been made for such solar cells with demonstrated efficiencies over 7%; however, their fundamental working principles are still under investigation. This Perspective is intended to offer our insights on the three major governing mechanisms in these intriguing ternary solar cells: charge transfer, energy transfer, and parallel-linkage. Through careful analysis of exemplary cases, we summarize the advantages and limitations of these three major mechanisms and suggest future research directions. For example, incorporating additional singlet fission or upconversion materials into the energy transfer dominant ternary solar cells has the potential to break the theoretical efficiency limit in single junction organic solar cells. Clearly, a feedback loop between fundamental understanding and materials selection is in urgent need to accelerate the efficiency improvement of these ternary solar cells.

Investigation of a “Sharps” Incident

DOE PAGES

Cournoyer, Michael Edward; Trujillo, Stanley; Schreiber, Stephen Bruce

2016-08-03

Special nuclear material research, process development, technology demonstration, and manufacturing capabilities are provided at the Los Alamos National Laboratory Plutonium Facility. Engineered barriers provide the most effective protection from radioactive and hazardous materials. The Worker Safety Security Team augments these passive safety feature by investigating incidents to identify appropriate prevention and mitigation measures. “Learning Teams” facilitate employee feedback loop and integration toward process improvement. Here, this article reports an investigation of a “Sharps” incident and reviews a case study of a technician that cuts his left thumb while making a gasket. Causal analysis of the sharps incident uncovered contributing factorsmore » that created the environment in which the incident occurred. Finally, latent organizational conditions that created error-likely situations or weakened defenses were identified and controlled. Effective improvements that reduce the probability or consequence of similar sharps incidents were implemented.« less

Low-temperature magnetotransport in Si/SiGe heterostructures on 300 mm Si wafers

NASA Astrophysics Data System (ADS)

Scappucci, Giordano; Yeoh, L.; Sabbagh, D.; Sammak, A.; Boter, J.; Droulers, G.; Kalhor, N.; Brousse, D.; Veldhorst, M.; Vandersypen, L. M. K.; Thomas, N.; Roberts, J.; Pillarisetty, R.; Amin, P.; George, H. C.; Singh, K. J.; Clarke, J. S.

Undoped Si/SiGe heterostructures are a promising material stack for the development of spin qubits in silicon. To deploy a qubit into high volume manufacturing in a quantum computer requires stringent control over substrate uniformity and quality. Electron mobility and valley splitting are two key electrical metrics of substrate quality relevant for qubits. Here we present low-temperature magnetotransport measurements of strained Si quantum wells with mobilities in excess of 100000 cm2/Vs fabricated on 300 mm wafers within the framework of advanced semiconductor manufacturing. These results are benchmarked against the results obtained in Si quantum wells deposited on 100 mm Si wafers in an academic research environment. To ensure rapid progress in quantum wells quality we have implemented fast feedback loops from materials growth, to heterostructure FET fabrication, and low temperature characterisation. On this topic we will present recent progress in developing a cryogenic platform for high-throughput magnetotransport measurements.

Impact of Somatic Mutations in the D-Loop of Mitochondrial DNA on the Survival of Oral Squamous Cell Carcinoma Patients

PubMed Central

Lin, Jin-Ching; Wang, Chen-Chi; Jiang, Rong-San; Wang, Wen-Yi; Liu, Shih-An

2015-01-01

Objectives The aim of this study was to investigate somatic mutations in the D-loop of mitochondrial DNA (mtDNA) and their impact on survival in oral squamous cell carcinoma patients. Materials and Methods Surgical specimen confirmed by pathological examination and corresponding non-cancerous tissues were collected from 120 oral squamous cell carcinoma patients. The sequence in the D-loop of mtDNA from non-cancerous tissues was compared with that from paired cancer samples and any sequence differences were recognized as somatic mutations. Results Somatic mutations in the D-loop of mtDNA were identified in 75 (62.5%) oral squamous cell carcinoma patients and most of them occurred in the poly-C tract. Although there were no significant differences in demographic and tumor-related features between participants with and without somatic mutation, the mutation group had a better survival rate (5 year disease-specific survival rate: 64.0% vs. 43.0%, P = 0.0266). Conclusion Somatic mutation in D-loop of mtDNA was associated with a better survival in oral squamous cell carcinoma patients. PMID:25906372

Complexities of high temperature metal fatigue: Some steps toward understanding

NASA Technical Reports Server (NTRS)

Manson, S. S.; Halford, G. R.

1983-01-01

After pointing out many of the complexities that attend high temperature metal fatigue beyond those already studied in the sub-creep range, a description of the micromechanisms of deformation and fracture is presented for several classes of materials that were studied over the past dozen years. Strainrange Partitioning (SRP) is used as a framework for interpreting the results. Several generic types of behavior were observed with regard both to deformation and fracture and each is discussed in the context of the micromechanisms involved. Treatment of cumulative fatigue damage and the possibility of ""healing'' of damage in successive loading loops, has led to a new interpretation of the Interaction Damage Rule of SRP. Using the concept of ""equivalent micromechanistic damage'' -- that the same damage on a microscopic scale is induced if the same hysteresis loops are generated, element for element -- it turns out the Interaction Damage Rule essentially compounds a number of variants of hysteresis loops, all of which have the same damage according to SRP concepts, into a set of loops each containing only one of the generic SRP strainranges. Thus the damage associcated with complex loops comprising several types of strainrange is analyzed by considering a combination of loops each containing only one type of strainrange. This concept is expanded to show how several independent loops can combine to ""heal'' creep damage in a complex loading history.

Open-Loop HIRF Experiments Performed on a Fault Tolerant Flight Control Computer

NASA Technical Reports Server (NTRS)

Koppen, Daniel M.

1997-01-01

During the third quarter of 1996, the Closed-Loop Systems Laboratory was established at the NASA Langley Research Center (LaRC) to study the effects of High Intensity Radiated Fields on complex avionic systems and control system components. This new facility provided a link and expanded upon the existing capabilities of the High Intensity Radiated Fields Laboratory at LaRC that were constructed and certified during 1995-96. The scope of the Closed-Loop Systems Laboratory is to place highly integrated avionics instrumentation into a high intensity radiated field environment, interface the avionics to a real-time flight simulation that incorporates aircraft dynamics, engines, sensors, actuators and atmospheric turbulence, and collect, analyze, and model aircraft performance. This paper describes the layout and functionality of the Closed-Loop Systems Laboratory, and the open-loop calibration experiments that led up to the commencement of closed-loop real-time flight experiments.

Based on optical fiber Michelson interferometer for acoustic emission detection experimental research

NASA Astrophysics Data System (ADS)

Liang, Yijun; Qu, Dandan; Deng, Hu

2013-08-01

A type of Michelson interferometer with two optical fiber loop reflectors acoustic emission sensor is proposed in the article to detect the vibrations produced by ultrasonic waves propagating in a solid body. Two optical fiber loop reflectors are equivalent to the sensing arm and the reference arm instead of traditional Michelson interferometer end reflecter Theoretical analyses indicate that the sensitivity of the system has been remarkably increased because of the decrease of the losses of light energy. The best operating point of optical fiber sensor is fixed by theoretical derivation and simulation of computer, and the signal frequency which is detected by the sensor is the frequency of input signal. PZT (Piezoelectric Ceramic) is powered by signal generator as known ultrasonic source, The Polarization controller is used to make the reflected light interference，The fiber length is changed by adjusting the DC voltage on the PZT with the fiber loop to make the sensor system response that ΔΦ is closed to π/2. the signal basis frequency detected by the sensor is the frequency of the input signal. Then impacts the surface of the marble slab with home-made mechanical acoustic emission source. And detect it. and then the frequency characteristic of acoustic emission signal is obtained by Fourier technique. The experimental results indicate that the system can identify the frequency characteristic of acoustic emission signal, and it can be also used to detect the surface feeble vibration which is generated by ultrasonic waves propagating in material structure.

Hysteresis modeling and identification of a dielectric electro-active polymer actuator using an APSO-based nonlinear Preisach NARX fuzzy model

NASA Astrophysics Data System (ADS)

Truong, Bui Ngoc Minh; Nam, Doan Ngoc Chi; Ahn, Kyoung Kwan

2013-09-01

Dielectric electro-active polymer (DEAP) materials are attractive since they are low cost, lightweight and have a large deformation capability. They have no operating noise, very low electric power consumption and higher performance and efficiency than competing technologies. However, DEAP materials generally have strong hysteresis as well as uncertain and nonlinear characteristics. These disadvantages can limit the efficiency in the use of DEAP materials. To address these limitations, this research will present the combination of the Preisach model and the dynamic nonlinear autoregressive exogenous (NARX) fuzzy model-based adaptive particle swarm optimization (APSO) identification algorithm for modeling and identification of the nonlinear behavior of one typical type of DEAP actuator. Firstly, open loop input signals are applied to obtain nonlinear features and to investigate the responses of the DEAP actuator system. Then, a Preisach model can be combined with a dynamic NARX fuzzy structure to estimate the tip displacement of a DEAP actuator. To optimize all unknown parameters of the designed combination, an identification scheme based on a least squares method and an APSO algorithm is carried out. Finally, experimental validation research is carefully completed, and the effectiveness of the proposed model is evaluated by employing various input signals.

Storm water monitoring along loop 202 and Salt River.

DOT National Transportation Integrated Search

2010-10-01

A comprehensive research program for the characterization of storm water runoff from an Arizona : highway was conducted from January through December 2007. The study area covered a portion of : the Loop 202 freeway west of Mesa Drive to a retention b...

SUSTAINABLE COLLEGE COMMUNITIES: INCORPORATING A SUSTAINABLE FOOD LOOP

EPA Science Inventory

The results of this project will include the physical components of the food loop (the composting system and the organic garden), as well as student research, education programs and partnerships with community organizations. An outward facing web site that chronicles the succe...

DIMENSIONS OF SIMULATION.

ERIC Educational Resources Information Center

CRAWFORD, MEREDITH P.

OPEN AND CLOSED LOOP SIMULATION IS DISCUSSED FROM THE VIEWPOINT OF RESEARCH AND DEVELOPMENT IN TRAINING TECHNIQUES. AREAS DISCUSSED INCLUDE--(1) OPEN-LOOP ENVIRONMENTAL SIMULATION, (2) SIMULATION NOT INVOLVING PEOPLE, (3) ANALYSIS OF OCCUPATIONS, (4) SIMULATION FOR TRAINING, (5) REAL-SIZE SYSTEM SIMULATION, (6) TECHNIQUES OF MINIATURIZATION, AND…

A Cleaner Process for Selective Recovery of Valuable Metals from Electronic Waste of Complex Mixtures of End-of-Life Electronic Products.

PubMed

Sun, Zhi; Xiao, Y; Sietsma, J; Agterhuis, H; Yang, Y

2015-07-07

In recent years, recovery of metals from electronic waste within the European Union has become increasingly important due to potential supply risk of strategic raw material and environmental concerns. Electronic waste, especially a mixture of end-of-life electronic products from a variety of sources, is of inherently high complexity in composition, phase, and physiochemical properties. In this research, a closed-loop hydrometallurgical process was developed to recover valuable metals, i.e., copper and precious metals, from an industrially processed information and communication technology waste. A two-stage leaching design of this process was adopted in order to selectively extract copper and enrich precious metals. It was found that the recovery efficiency and extraction selectivity of copper both reached more than 95% by using ammonia-based leaching solutions. A new electrodeposition process has been proven feasible with 90% current efficiency during copper recovery, and the copper purity can reach 99.8 wt %. The residue from the first-stage leaching was screened into coarse and fine fractions. The coarse fraction was returned to be releached for further copper recovery. The fine fraction was treated in the second-stage leaching using sulfuric acid to further concentrate precious metals, which could achieve a 100% increase in their concentrations in the residue with negligible loss into the leaching solution. By a combination of different leaching steps and proper physical separation of light materials, this process can achieve closed-loop recycling of the waste with significant efficiency.

Loop and void damage during heavy ion irradiation on nanocrystalline and coarse grained tungsten: Microstructure, effect of dpa rate, temperature, and grain size

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

El-Atwani, O.; Esquivel, E.; Efe, M.

Displacement damage, through heavy ion irradiation was studied on two tungsten grades (coarse grained tungsten (CGW) and nanocrystalline and ultrafine grained tungsten (NCW)) using different displacement per atom rates and different irradiation temperatures (RT and 1050 K). Percentage of <111> and <100> type loops at the irradiation conditions was determined. Irradiation damage in the microstructure was quantified using average loop areas and densities (method A) and loop areal fraction in the grain matrices under 2-beam diffraction conditions (method B). Average values of <111> and <100> loops were calculated from method A. Loop coalescence was shown to occur for CGW atmore » 0.25 dpa. Using both methods of quantifying microstructural damage, no effect of dpa rate was observed and damage in CGW was shown to be the same at RT and 1050 K. Swelling from voids observed at 1050 K was quantified. The loop damage in NCW was compared to CGW at the same diffraction and imaging conditions. NCW was shown to possess enhanced irradiation resistance at RT regarding loop damage and higher swelling resistance at 1050 K compared to CGW. For irradiation at 1050 K, the NCW was shown to have a similar defect densities to the CGW which is attributed to higher surface effects in the CGW, vacancy loop growth to voids and a better sink efficiency in the CGW deduced from the vacancy distribution profiles from Kinetic Monte Carlo simulations. Loop density and swelling was shown to have similar values in grains sizes that range from 80-600 nm. No loop or void denuded zones occurred at any of the irradiation conditions. This work has a collection of experiments and conclusions that are of vital importance to materials and nuclear communities.« less

Loop and void damage during heavy ion irradiation on nanocrystalline and coarse grained tungsten: Microstructure, effect of dpa rate, temperature, and grain size

DOE PAGES

El-Atwani, O.; Esquivel, E.; Efe, M.; ...

2018-02-20

Displacement damage, through heavy ion irradiation was studied on two tungsten grades (coarse grained tungsten (CGW) and nanocrystalline and ultrafine grained tungsten (NCW)) using different displacement per atom rates and different irradiation temperatures (RT and 1050 K). Percentage of <111> and <100> type loops at the irradiation conditions was determined. Irradiation damage in the microstructure was quantified using average loop areas and densities (method A) and loop areal fraction in the grain matrices under 2-beam diffraction conditions (method B). Average values of <111> and <100> loops were calculated from method A. Loop coalescence was shown to occur for CGW atmore » 0.25 dpa. Using both methods of quantifying microstructural damage, no effect of dpa rate was observed and damage in CGW was shown to be the same at RT and 1050 K. Swelling from voids observed at 1050 K was quantified. The loop damage in NCW was compared to CGW at the same diffraction and imaging conditions. NCW was shown to possess enhanced irradiation resistance at RT regarding loop damage and higher swelling resistance at 1050 K compared to CGW. For irradiation at 1050 K, the NCW was shown to have a similar defect densities to the CGW which is attributed to higher surface effects in the CGW, vacancy loop growth to voids and a better sink efficiency in the CGW deduced from the vacancy distribution profiles from Kinetic Monte Carlo simulations. Loop density and swelling was shown to have similar values in grains sizes that range from 80-600 nm. No loop or void denuded zones occurred at any of the irradiation conditions. This work has a collection of experiments and conclusions that are of vital importance to materials and nuclear communities.« less

ADVANCED CUTTINGS TRANSPORT STUDY

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

Stefan Miska; Troy Reed; Ergun Kuru

2004-09-30

The Advanced Cuttings Transport Study (ACTS) was a 5-year JIP project undertaken at the University of Tulsa (TU). The project was sponsored by the U.S. Department of Energy (DOE) and JIP member companies. The objectives of the project were: (1) to develop and construct a new research facility that would allow three-phase (gas, liquid and cuttings) flow experiments under ambient and EPET (elevated pressure and temperature) conditions, and at different angle of inclinations and drill pipe rotation speeds; (2) to conduct experiments and develop a data base for the industry and academia; and (3) to develop mechanistic models for optimizationmore » of drilling hydraulics and cuttings transport. This project consisted of research studies, flow loop construction and instrumentation development. Following a one-year period for basic flow loop construction, a proposal was submitted by TU to the DOE for a five-year project that was organized in such a manner as to provide a logical progression of research experiments as well as additions to the basic flow loop. The flow loop additions and improvements included: (1) elevated temperature capability; (2) two-phase (gas and liquid, foam etc.) capability; (3) cuttings injection and removal system; (4) drill pipe rotation system; and (5) drilling section elevation system. In parallel with the flow loop construction, hydraulics and cuttings transport studies were preformed using drilling foams and aerated muds. In addition, hydraulics and rheology of synthetic drilling fluids were investigated. The studies were performed under ambient and EPET conditions. The effects of temperature and pressure on the hydraulics and cuttings transport were investigated. Mechanistic models were developed to predict frictional pressure loss and cuttings transport in horizontal and near-horizontal configurations. Model predictions were compared with the measured data. Predominantly, model predictions show satisfactory agreements with the measured data. As a part of this project, instrumentation was developed to monitor cuttings beds and characterize foams in the flow loop. An ultrasonic-based monitoring system was developed to measure cuttings bed thickness in the flow loop. Data acquisition software controls the system and processes the data. Two foam generating devices were designed and developed to produce foams with specified quality and texture. The devices are equipped with a bubble recognition system and an in-line viscometer to measure bubble size distribution and foam rheology, respectively. The 5-year project is completed. Future research activities will be under the umbrella of Tulsa University Drilling Research Projects. Currently the flow loop is being used for testing cuttings transport capacity of aqueous and polymer-based foams under elevated pressure and temperature conditions. Subsequently, the effect of viscous sweeps on cuttings transport under elevated pressure and temperature conditions will be investigated using the flow loop. Other projects will follow now that the ''steady state'' phase of the project has been achieved.« less

AGARD (Advisory Group for Aerospace Research & Development) Index of Publications, 1986-1988

DTIC Science & Technology

1989-08-01

measurements are used in forming the navigation and the baro-inertial loop as well The system communicates with equations to solve for the user position...processing techniques in the tracking ROBERT P. DENARO and G JEFFREY GEIER In AGARD, The loops . and later in the navigation processing ot the Kalman...avionics investigations to predict the dynamic structural response of flexible assessment. The current status of real time, pilot-in-the- loop flight

A distance estimate to the Cygnus Loop based on the distances to two stars located within the remnant

NASA Astrophysics Data System (ADS)

Fesen, Robert A.; Neustadt, Jack M. M.; Black, Christine S.; Milisavljevic, Dan

2018-04-01

Underlying nearly every quantitative discussion of the Cygnus Loop supernova remnant is uncertainty about its distance. Here, we present optical images and spectra of nebulosities around two stars whose mass-loss material appears to have interacted with the remnant's expanding shock front and thus can be used to estimate the Cygnus Loop's distance. Narrow passband images reveal a small emission-line nebula surrounding an M4 red giant near the remnant's eastern nebula NGC 6992. Optical spectra of the nebula show it to be shock-heated with significantly higher electron densities than seen in the remnant's filaments. This along with a bow-shaped morphology suggests it is likely red giant mass-loss material shocked and accelerated by passage of the Cygnus Loop's blast wave. We also identify a B7 V star located along the remnant's northwestern limb, which also appears to have interacted with the remnant's shock wave. It lies within a small arc of nebulosity in an unusually complex region of curved and distorted filaments along the remnant's northern shock front suggestive of a localized disturbance of the shock front due to the B star's stellar winds. Based on the assumption that these two stars lie inside the remnant, combined with an estimated distance to a molecular cloud situated along the remnant's western limb, we propose a distance to the Cygnus Loop of 1.0 ± 0.2 kpc. Although larger than several recent estimates of 500-800 pc, a distance ≃1 kpc helps resolve difficulties with the remnant's postshock cosmic ray and gas pressure ratio and estimated supernova explosion energy.

How do postgraduate GP trainees regulate their learning and what helps and hinders them? A qualitative study.

PubMed

Sagasser, Margaretha H; Kramer, Anneke W M; van der Vleuten, Cees P M

2012-08-06

Self-regulation is essential for professional development. It involves monitoring of performance, identifying domains for improvement, undertaking learning activities, applying newly learned knowledge and skills and self-assessing performance. Since self-assessment alone is ineffective in identifying weaknesses, learners should seek external feedback too. Externally regulated educational interventions, like reflection, learning portfolios, assessments and progress meetings, are increasingly used to scaffold self-regulation.The aim of this study is to explore how postgraduate trainees regulate their learning in the workplace, how external regulation promotes self-regulation and which elements facilitate or impede self-regulation and learning. In a qualitative study with a phenomenologic approach we interviewed first- and third-year GP trainees from two universities in the Netherlands. Twenty-one verbatim transcripts were coded. Through iterative discussion the researchers agreed on the interpretation of the data and saturation was reached. Trainees used a short and a long self-regulation loop. The short loop took one week at most and was focused on problems that were easy to resolve and needed minor learning activities. The long loop was focused on complex or recurring problems needing multiple and planned longitudinal learning activities. External assessments and formal training affected the long but not the short loop. The supervisor had a facilitating role in both loops. Self-confidence was used to gauge competence.Elements influencing self-regulation were classified into three dimensions: personal (strong motivation to become a good doctor), interpersonal (stimulation from others) and contextual (organizational and educational features). Trainees did purposefully self-regulate their learning. Learning in the short loop may not be visible to others. Trainees should be encouraged to actively seek and use external feedback in both loops. An important question for further research is which educational interventions might be used to scaffold learning in the short loop. Investing in supervisor quality remains important, since they are close to trainee learning in both loops.

How do postgraduate GP trainees regulate their learning and what helps and hinders them? A qualitative study

PubMed Central

2012-01-01

Background Self-regulation is essential for professional development. It involves monitoring of performance, identifying domains for improvement, undertaking learning activities, applying newly learned knowledge and skills and self-assessing performance. Since self-assessment alone is ineffective in identifying weaknesses, learners should seek external feedback too. Externally regulated educational interventions, like reflection, learning portfolios, assessments and progress meetings, are increasingly used to scaffold self-regulation. The aim of this study is to explore how postgraduate trainees regulate their learning in the workplace, how external regulation promotes self-regulation and which elements facilitate or impede self-regulation and learning. Methods In a qualitative study with a phenomenologic approach we interviewed first- and third-year GP trainees from two universities in the Netherlands. Twenty-one verbatim transcripts were coded. Through iterative discussion the researchers agreed on the interpretation of the data and saturation was reached. Results Trainees used a short and a long self-regulation loop. The short loop took one week at most and was focused on problems that were easy to resolve and needed minor learning activities. The long loop was focused on complex or recurring problems needing multiple and planned longitudinal learning activities. External assessments and formal training affected the long but not the short loop. The supervisor had a facilitating role in both loops. Self-confidence was used to gauge competence.Elements influencing self-regulation were classified into three dimensions: personal (strong motivation to become a good doctor), interpersonal (stimulation from others) and contextual (organizational and educational features). Conclusions Trainees did purposefully self-regulate their learning. Learning in the short loop may not be visible to others. Trainees should be encouraged to actively seek and use external feedback in both loops. An important question for further research is which educational interventions might be used to scaffold learning in the short loop. Investing in supervisor quality remains important, since they are close to trainee learning in both loops. PMID:22866981

A Conversion of Wheatstone Bridge to Current-Loop Signal Conditioning for Strain Gages

NASA Technical Reports Server (NTRS)

Anderson, Karl F.

1995-01-01

Current loop circuitry replaced Wheatstone bridge circuitry to signal-condition strain gage transducers in more than 350 data channels for two different test programs at NASA Dryden Flight Research Center. The uncorrected test data from current loop circuitry had a lower noise level than data from comparable Wheatstone bridge circuitry, were linear with respect to gage-resistance change, and were uninfluenced by varying lead-wire resistance. The current loop channels were easier for the technicians to set up, verify, and operate than equivalent Wheatstone bridge channels. Design choices and circuit details are presented in this paper in addition to operational experience.

Irradiation Testing Vehicles for Fast Reactors from Open Test Assemblies to Closed Loops

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

Sienicki, James J.; Grandy, Christopher

A review of irradiation testing vehicle approaches and designs that have been incorporated into past Sodium-Cooled Fast Reactors (SFRs) or envisioned for incorporation has been carried out. The objective is to understand the essential features of the approaches and designs so that they can inform test vehicle designs for a future U.S. Fast Test Reactor. Fast test reactor designs examined include EBR-II, FFTF, JOYO, BOR-60, PHÉNIX, JHR, and MBIR. Previous designers exhibited great ingenuity in overcoming design and operational challenges especially when the original reactor plant’s mission changed to an irradiation testing mission as in the EBRII reactor plant. Themore » various irradiation testing vehicles can be categorized as: Uninstrumented open assemblies that fit into core locations; Instrumented open test assemblies that fit into special core locations; Self-contained closed loops; and External closed loops. A special emphasis is devoted to closed loops as they are regarded as a very desirable feature of a future U.S. Fast Test Reactor. Closed loops are an important technology for irradiation of fuels and materials in separate controlled environments. The impact of closed loops on the design of fast reactors is also discussed in this report.« less

Characterisation of case depth in induction-hardened medium carbon steels based on magnetic minor hysteresis loop measurement technique

NASA Astrophysics Data System (ADS)

He, Cunfu; Yang, Meng; Liu, Xiucheng; Wang, Xueqian; Wu, Bin

2017-11-01

The magnetic hysteresis behaviours of ferromagnetic materials vary with the heat treatment-induced micro-structural changes. In the study, the minor hysteresis loop measurement technique was used to quantitatively characterise the case depth in two types of medium carbon steels. Firstly, high-frequency induction quenching was applied in rod samples to increase the volume fraction of hard martensite to the soft ferrite/pearlite (or sorbite) in the sample surface. In order to determine the effective and total case depth, a complementary error function was employed to fit the measured hardness-depth profiles of induction-hardened samples. The cluster of minor hysteresis loops together with the tangential magnetic field (TMF) were recorded from all the samples and the comparative study was conducted among three kinds of magnetic parameters, which were sensitive to the variation of case depth. Compared to the parameters extracted from an individual minor loop and the distortion factor of the TMF, the magnitude of three-order harmonic of TMF was more suitable to indicate the variation in case depth. Two new minor-loop coefficients were introduced by combining two magnetic parameters with cumulative statistics of the cluster of minor-loops. The experimental results showed that the two coefficients monotonically linearly varied with the case depth within the carefully selected magnetisation region.

Optical microresonator for application to an opto-electronic oscillator

NASA Astrophysics Data System (ADS)

Wu, Yu-Mei; Vivien, Laurent; Cassan, Eric; Luong, Vu Hai Nam; Nguyen, Lam Duy; Journet, Bernard

2010-02-01

Optoelectronic oscillators are classically based on a feedback fiber loop acting as a delay line for high spectral purity. One of the problems due to long fiber loops is the size and the requirement of temperature control. Going toward integrated solutions requires the introduction of optical resonators with a very high quality factor. A structure based on silicon on insulator material has been designed for application to an oscillator working at 8 GHz. The micro-resonator has a stadium shape with a ridge of 30 nm height, 1 μm width, a millimetric radius and a gap of some microns in agreement with the required free spectral range. A quality factor of 500000 can be achieved leading to an equivalent fiber loop of 2 km.

Imagery and spectroscopy of supernova remnants and H-2 regions

NASA Technical Reports Server (NTRS)

Dufour, R. J.

1984-01-01

Research activities relating to supernova remnants were summarized. The topics reviewed include: progenitor stars of supernova remnants, UV/optical/radio/X-ray imagery of selected regions in the Cygnus Loop, UV/optical spectroscopy of the Cygnus Loop spur, and extragalactic supernova remnant spectra.

A 5 Gb/s CMOS adaptive equalizer for serial link

NASA Astrophysics Data System (ADS)

Wu, Hongbing; Wang, Jingyu; Liu, Hongxia

2018-04-01

A 5 Gb/s adaptive equalizer with a new adaptation scheme is presented here by using 0.13 μm CMOS process. The circuit consists of the combination of equalizer amplifier, limiter amplifier and adaptation loop. The adaptive algorithm exploits both the low frequency gain loop and the equalizer loop to minimize the inter-symbol interference (ISI) for a variety of cable characteristics. In addition, an offset cancellation loop is used to alleviate the offset influence of the signal path. The adaptive equalizer core occupies an area of 0.3567 mm2 and consumes a power consumption of 81.7 mW with 1.8 V power supply. Experiment results demonstrate that the equalizer could compensate for a designed cable loss with 0.23 UI peak-to-peak jitter. Project supported by the National Natural Science Foundation of China (No. 61376099), the Foundation for Fundamental Research of China (No. JSZL2016110B003), and the Major Fundamental Research Program of Shaanxi (No. 2017ZDJC-26).

Real-time flutter analysis of an active flutter-suppression system on a remotely piloted research aircraft

NASA Technical Reports Server (NTRS)

Gilyard, G. B.; Edwards, J. W.

1983-01-01

Flight flutter-test results of the first aeroelastic research wing (ARW-1) of NASA's drones for aerodynamic and structural testing program are presented. The flight-test operation and the implementation of the active flutter-suppression system are described as well as the software techniques used to obtain real-time damping estimates and the actual flutter testing procedure. Real-time analysis of fast-frequency aileron excitation sweeps provided reliable damping estimates. The open-loop flutter boundary was well defined at two altitudes; a maximum Mach number of 0.91 was obtained. Both open-loop and closed-loop data were of exceptionally high quality. Although the flutter-suppression system provided augmented damping at speeds below the flutter boundary, an error in the implementation of the system resulted in the system being less stable than predicted. The vehicle encountered system-on flutter shortly after crossing the open-loop flutter boundary on the third flight and was lost. The aircraft was rebuilt. Changes made in real-time test techniques are included.

Analysis and Design of a Speed and Position System for Maglev Vehicles

PubMed Central

Dai, Chunhui; Dou, Fengshan; Song, Xianglei; Long, Zhiqiang

2012-01-01

This paper mainly researches one method of speed and location detection for maglev vehicles. As the maglev train doesn't have any physical contact with the rails, it has to use non-contact measuring methods. The technology based on the inductive loop-cable could fulfill the requirement by using an on-board antenna which could detect the alternating magnetic field produced by the loop-cable on rails. This paper introduces the structure of a speed and position system, and analyses the electromagnetic field produced by the loop-cable. The equivalent model of the loop-cable is given and the most suitable component of the magnetic flux density is selected. Then the paper also compares the alternating current (AC) resistance and the quality factor between two kinds of coils which the antenna is composed of. The effect of the rails to the signal receiving is also researched and then the structure of the coils is improved. Finally, considering the common-mode interference, 8-word coils are designed and analyzed. PMID:23012504

Analysis and design of a speed and position system for maglev vehicles.

PubMed

Dai, Chunhui; Dou, Fengshan; Song, Xianglei; Long, Zhiqiang

2012-01-01

This paper mainly researches one method of speed and location detection for maglev vehicles. As the maglev train doesn't have any physical contact with the rails, it has to use non-contact measuring methods. The technology based on the inductive loop-cable could fulfill the requirement by using an on-board antenna which could detect the alternating magnetic field produced by the loop-cable on rails. This paper introduces the structure of a speed and position system, and analyses the electromagnetic field produced by the loop-cable. The equivalent model of the loop-cable is given and the most suitable component of the magnetic flux density is selected. Then the paper also compares the alternating current (AC) resistance and the quality factor between two kinds of coils which the antenna is composed of. The effect of the rails to the signal receiving is also researched and then the structure of the coils is improved. Finally, considering the common-mode interference, 8-word coils are designed and analyzed.

Modeling Plasticity of Ni3Al-Based L12 Intermetallic Single Crystals-I. Anomalous Temperature Dependence of the Flow Behavior (Preprint)

DTIC Science & Technology

2006-07-01

dislocation-loop expansion . The new model was used to simulate the thermally reversible flow behaviour for C-S type two-step deformation, and the results are...implemented into the finite element software ABAQUS through a User MATerial subroutine (UMAT). A tangent modulus method [48] was used for the time...locking under a dislocation loop- expansion configuration. This approach was motivated by modern understanding of dislocation mechanisms for Ni3Al

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

None

Oberlin College’s Adam Joseph Lewis Center for Environmental Studies is a high-performance building featuring an expansive photovoltaic system and a closed-loop groundwater heat pump system. Designers incorporated energy-efficient components and materials

Integration of Carbon Fiber Composite Materials into Air-Cooled Reciprocating Piston Engines for UA V Applications

DTIC Science & Technology

2012-05-04

Wrapping Pre-impregnated CFRP unidirectional and +/-45° woven carbon fiber fabric prepreg was used for the loop. Pre-impregnated material was a...viable application for the connecting rod because there are no complex geometries for the CFRP to negotiate. Prepreg aids in maintaining proper fiber

Audiovisual Materials for the Engineering Technologies.

ERIC Educational Resources Information Center

O'Brien, Janet S., Comp.

A list of audiovisual materials suitable for use in engineering technology courses is provided. This list includes titles of 16mm films, 8mm film loops, slidetapes, transparencies, audio tapes, and videotapes. Given for each title are: source, format, length of film or tape or number of slides or transparencies, whether color or black-and-white,…

Displacement Fields and Self-Energies of Circular and Polygonal Dislocation Loops in Homogeneous and Layered Anisotropic Solids

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

Gao, Yanfei; Larson, Ben C.

There are large classes of materials problems that involve the solutions of stress, displacement, and strain energy of dislocation loops in elastically anisotropic solids, including increasingly detailed investigations of the generation and evolution of irradiation induced defect clusters ranging in sizes from the micro- to meso-scopic length scales. Based on a two-dimensional Fourier transform and Stroh formalism that are ideal for homogeneous and layered anisotropic solids, we have developed robust and computationally efficient methods to calculate the displacement fields for circular and polygonal dislocation loops. Using the homogeneous nature of the Green tensor of order -1, we have shown thatmore » the displacement and stress fields of dislocation loops can be obtained by numerical quadrature of a line integral. In addition, it is shown that the sextuple integrals associated with the strain energy of loops can be represented by the product of a pre-factor containing elastic anisotropy effects and a universal term that is singular and equal to that for elastic isotropic case. Furthermore, we have found that the self-energy pre-factor of prismatic loops is identical to the effective modulus of normal contact, and the pre-factor of shear loops differs from the effective indentation modulus in shear by only a few percent. These results provide a convenient method for examining dislocation reaction energetic and efficient procedures for numerical computation of local displacements and stresses of dislocation loops, both of which play integral roles in quantitative defect analyses within combined experimental–theoretical investigations.« less

Displacement Fields and Self-Energies of Circular and Polygonal Dislocation Loops in Homogeneous and Layered Anisotropic Solids

DOE PAGES

Gao, Yanfei; Larson, Ben C.

2015-06-19

There are large classes of materials problems that involve the solutions of stress, displacement, and strain energy of dislocation loops in elastically anisotropic solids, including increasingly detailed investigations of the generation and evolution of irradiation induced defect clusters ranging in sizes from the micro- to meso-scopic length scales. Based on a two-dimensional Fourier transform and Stroh formalism that are ideal for homogeneous and layered anisotropic solids, we have developed robust and computationally efficient methods to calculate the displacement fields for circular and polygonal dislocation loops. Using the homogeneous nature of the Green tensor of order -1, we have shown thatmore » the displacement and stress fields of dislocation loops can be obtained by numerical quadrature of a line integral. In addition, it is shown that the sextuple integrals associated with the strain energy of loops can be represented by the product of a pre-factor containing elastic anisotropy effects and a universal term that is singular and equal to that for elastic isotropic case. Furthermore, we have found that the self-energy pre-factor of prismatic loops is identical to the effective modulus of normal contact, and the pre-factor of shear loops differs from the effective indentation modulus in shear by only a few percent. These results provide a convenient method for examining dislocation reaction energetic and efficient procedures for numerical computation of local displacements and stresses of dislocation loops, both of which play integral roles in quantitative defect analyses within combined experimental–theoretical investigations.« less

Flexor Tendon Repair With Looped Suture: 1 Versus 2 Knots.

PubMed

Gil, Joseph A; Skjong, Christian; Katarincic, Julia A; Got, Christopher

2016-03-01

To assess the strength of flexor tendon repair with looped suture. We hypothesized that, after passing the intact looped suture in the desired repair configuration, splitting the loop and tying 2 independent knots would increase the strength of flexor tendon repair. Thirty-two flexor tendons were harvested and were sharply transected in zone II. The tendons were repaired with a 4-strand core suture repair using 3-0 looped nonabsorbable nylon suture. The harvested tendons were randomly assigned and repaired with either a 1- or a 2-knot construct. The repaired flexor tendons were fixed in a servohydraulic material testing system and were loaded to failure either with uniaxial tension or cyclically. The average force at failure was 43 N for the 1-knot repair and 28 N for the 2-knot repair. The mode of failure of 15 of the flexor tendon repairs that were cyclically loaded to failure was suture pull-out. The average number of cycles and force in cyclic testing that caused failure of flexor tendon repairs was 134 cycles and 31 N for tendons repaired with looped 3-0 suture tied with 1 knot and 94 cycles and 33 N for tendons repaired with looped 3-0 suture tied with 2 knots. Our hypothesis was disproved by the results of this study. This study suggests that, when using looped suture, tying 2 independent knots instead of tying a single knot does not increase the strength of the flexor tendon repair. Copyright © 2016 American Society for Surgery of the Hand. Published by Elsevier Inc. All rights reserved.

Calibrating Nonlinear Soil Material Properties for Seismic Analysis Using Soil Material Properties Intended for Linear Analysis

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

Spears, Robert Edward; Coleman, Justin Leigh

2015-08-01

Seismic analysis of nuclear structures is routinely performed using guidance provided in “Seismic Analysis of Safety-Related Nuclear Structures and Commentary (ASCE 4, 1998).” This document, which is currently under revision, provides detailed guidance on linear seismic soil-structure-interaction (SSI) analysis of nuclear structures. To accommodate the linear analysis, soil material properties are typically developed as shear modulus and damping ratio versus cyclic shear strain amplitude. A new Appendix in ASCE 4-2014 (draft) is being added to provide guidance for nonlinear time domain SSI analysis. To accommodate the nonlinear analysis, a more appropriate form of the soil material properties includes shear stressmore » and energy absorbed per cycle versus shear strain. Ideally, nonlinear soil model material properties would be established with soil testing appropriate for the nonlinear constitutive model being used. However, much of the soil testing done for SSI analysis is performed for use with linear analysis techniques. Consequently, a method is described in this paper that uses soil test data intended for linear analysis to develop nonlinear soil material properties. To produce nonlinear material properties that are equivalent to the linear material properties, the linear and nonlinear model hysteresis loops are considered. For equivalent material properties, the shear stress at peak shear strain and energy absorbed per cycle should match when comparing the linear and nonlinear model hysteresis loops. Consequently, nonlinear material properties are selected based on these criteria.« less

Numerical analysis of stress effects on Frank loop evolution during irradiation in austenitic Fe&z.sbnd;Cr&z.sbnd;Ni alloy

NASA Astrophysics Data System (ADS)

Tanigawa, Hiroyasu; Katoh, Yutai; Kohyama, Akira

1995-08-01

Effects of applied stress on early stages of interstitial type Frank loop evolution were investigated by both numerical calculation and irradiation experiments. The final objective of this research is to propose a comprehensive model of complex stress effects on microstructural evolution under various conditions. In the experimental part of this work, the microstructural analysis revealed that the differences in resolved normal stress caused those in the nucleation rates of Frank loops on {111} crystallographic family planes, and that with increasing external applied stress the total nucleation rate of Frank loops was increased. A numerical calculation was carried out primarily to evaluate the validity of models of stress effects on nucleation processes of Frank loop evolution. The calculation stands on rate equuations which describe evolution of point defects, small points defect clusters and Frank loops. The rate equations of Frank loop evolution were formulated for {111} planes, considering effects of resolved normal stress to clustering processes of small point defects and growth processes of Frank loops, separately. The experimental results and the predictions from the numerical calculation qualitatively coincided well with each other.

Eye patches: Protein assembly of index-gradient squid lenses

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

Cai, J.; Townsend, J. P.; Dodson, T. C.

A parabolic relationship between lens radius and refractive index allows spherical lenses to avoid spherical aberration. We show that in squid, patchy colloidal physics resulted from an evolutionary radiation of globular S-crystallin proteins. Small-angle x-ray scattering experiments on lens tissue show colloidal gels of S-crystallins at all radial positions. Sparse lens materials form via low-valence linkages between disordered loops protruding from the protein surface. The loops are polydisperse and bind via a set of hydrogen bonds between disordered side chains. Peripheral lens regions with low particle valence form stable, volume-spanning gels at low density, whereas central regions with higher averagemore » valence gel at higher densities. The proteins demonstrate an evolved set of linkers for self-assembly of nanoparticles into volumetric materials.« less

The Business Emergency Operations Center (BEOC) - A Model for Inter-Agency and Inter-Sector Communication and Collaboration

DTIC Science & Technology

2011-06-01

of Observe, Orient, Decide, Act (OODA) and Sense, Interpret, Decide, Act ( SIDA ) loops is important to understand and research as part of this...C2 process loops, OODA, developed by John Boyd, (Coram 2002, Lind 1985) and/or SIDA , (Haeckel 2001) are functioning at multiple levels and the...model of C2 is grounded in OODA and SIDA loops addressed earlier in this paper. During exercises, the salient activity of moving through the process

RELAP5-3D Modeling of Heat Transfer Components (Intermediate Heat Exchanger and Helical-Coil Steam Generator) for NGNP Application

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

N. A. Anderson; P. Sabharwall

2014-01-01

The Next Generation Nuclear Plant project is aimed at the research and development of a helium-cooled high-temperature gas reactor that could generate both electricity and process heat for the production of hydrogen. The heat from the high-temperature primary loop must be transferred via an intermediate heat exchanger to a secondary loop. Using RELAP5-3D, a model was developed for two of the heat exchanger options a printed-circuit heat exchanger and a helical-coil steam generator. The RELAP5-3D models were used to simulate an exponential decrease in pressure over a 20 second period. The results of this loss of coolant analysis indicate thatmore » heat is initially transferred from the primary loop to the secondary loop, but after the decrease in pressure in the primary loop the heat is transferred from the secondary loop to the primary loop. A high-temperature gas reactor model should be developed and connected to the heat transfer component to simulate other transients.« less

Rigid Body Rate Inference from Attitude Variation

NASA Technical Reports Server (NTRS)

Bar-Itzhack, I. Y.; Harman, Richard R.; Thienel, Julie K.

2006-01-01

In this paper we research the extraction of the angular rate vector from attitude information without differentiation, in particular from quaternion measurements. We show that instead of using a Kalman filter of some kind, it is possible to obtain good rate estimates, suitable for spacecraft attitude control loop damping, using simple feedback loops, thereby eliminating the need for recurrent covariance computation performed when a Kalman filter is used. This considerably simplifies the computations required for rate estimation in gyro-less spacecraft. Some interesting qualities of the Kalman filter gain are explored, proven and utilized. We examine two kinds of feedback loops, one with varying gain that is proportional to the well known Q matrix, which is computed using the measured quaternion, and the other type of feedback loop is one with constant coefficients. The latter type includes two kinds; namely, a proportional feedback loop, and a proportional-integral feedback loop. The various schemes are examined through simulations and their performance is compared. It is shown that all schemes are adequate for extracting the angular velocity at an accuracy suitable for control loop damping.

On the Extraction of Angular Velocity from Attitude Measurements

NASA Technical Reports Server (NTRS)

Bar-Itzhack, I. Y.; Harman, Richard R.; Thienel, Julie K.

2006-01-01

In this paper we research the extraction of the angular rate vector from attitude information without differentiation, in particular from quaternion measurements. We show that instead of using a Kalman filter of some kind, it is possible to obtain good rate estimates, suitable for spacecraft attitude control loop damping, using simple feedback loops, thereby eliminating the need for recurrent covariance computation performed when a Kalman filter is used. This considerably simplifies the computations required for rate estimation in gyro-less spacecraft. Some interesting qualities of the Kalman filter gain are explored, proven and utilized. We examine two kinds of feedback loops, one with varying gain that is proportional to the well known Q matrix, which is computed using the measured quaternion, and the other type of feedback loop is one with constant coefficients. The latter type includes two kinds; namely, a proportional feedback loop, and a proportional-integral feedback loop. The various schemes are examined through simulations and their performance is compared. It is shown that all schemes are adequate for extracting the angular velocity at an accuracy suitable for control loop damping.

Dislocation loop models for the high temperature creep of Al-5.5 at.% Mg alloy

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

An, S.U.; Blum, W.

1995-04-15

The Al-5.5 at.% Mg alloy is a typical class I type solution hardened material. The dislocation loop models proposed by Orlova and Cadek and by Mills et al., respectively are widely applied models in describing the high temperature creep behavior of the Al-5.5 at.% Mg alloy. These models, however, are in conflict in explaining dislocation loop theory. Orlova and Cadek suggest that in class I solution hardened alloys screw dislocations are relatively easier to migrate because they are subject to a smaller resistance in motion than edge dislocations. Consequently, the migration rate of screw dislocations is higher than that ofmore » edge dislocations. However, since dislocation loops are composed of both screw and edge components, the overall migration rate of screw dislocations are reduced by that of the edge component. Mills et al. on the contrary, used a different dislocation loop model. As the loop grows while it moves, it takes on the shape of an ellipsoid due to the unbalance in growth rate, the score segment moving much easier than the edge. Therefore, as shown in the results of the stress reduction tests, rapid elastic ({Delta} {var_epsilon}{sub el}) and anelastic contraction ({Delta} {var_epsilon}{sub an}) occur simultaneously directly after stress reduction. During the movement of the dislocation loop, the screw component hence becomes severely curved, while the edge component retains a straight line. This has been proved through dislocation structure observations by TEM.« less

Saturable inductor and transformer structures for magnetic pulse compression

DOEpatents

Birx, Daniel L.; Reginato, Louis L.

1990-01-01

Saturable inductor and transformer for magnetic compression of an electronic pulse, using a continuous electrical conductor looped several times around a tightly packed core of saturable inductor material.

Loop Diuretics in the Treatment of Hypertension.

PubMed

Malha, Line; Mann, Samuel J

2016-04-01

Loop diuretics are not recommended in current hypertension guidelines largely due to the lack of outcome data. Nevertheless, they have been shown to lower blood pressure and to offer potential advantages over thiazide-type diuretics. Torsemide offers advantages of longer duration of action and once daily dosing (vs. furosemide and bumetanide) and more reliable bioavailability (vs. furosemide). Studies show that the previously employed high doses of thiazide-type diuretics lower BP more than furosemide. Loop diuretics appear to have a preferable side effect profile (less hyponatremia, hypokalemia, and possibly less glucose intolerance). Studies comparing efficacy and side effect profiles of loop diuretics with the lower, currently widely prescribed, thiazide doses are needed. Research is needed to fill gaps in knowledge and common misconceptions about loop diuretic use in hypertension and to determine their rightful place in the antihypertensive arsenal.

Loops of Jupiter

NASA Astrophysics Data System (ADS)

Opolski, Antoni

2014-12-01

Professor Antoni Opolski was actively interested in astronomy after his retirement in 1983. He especially liked to study the works of the famous astronomer Copernicus getting inspiration for his own work. Opolski started his work on planetary loops in 2011 continuing it to the end of 2012 . During this period calculations, drawings, tables, and basic descriptions of all the planets of the Solar System were created with the use of a piece of paper and a pencil only. In 2011 Antoni Opolski asked us to help him in editing the manuscript and preparing it for publication. We have been honored having the opportunity to work on articles on planetary loops with Antoni Opolski in his house for several months. In the middle of 2012 the detailed material on Jupiter was ready. However, professor Opolski improved the article by smoothing the text and preparing new, better drawings. Finally the article ''Loops of Jupiter'', written by the 99- year old astronomer, was published in the year of his 100th birthday.

Flow Components in a NaK Test Loop Designed to Simulate Conditions in a Nuclear Surface Power Reactor

NASA Astrophysics Data System (ADS)

Polzin, Kurt A.; Godfroy, Thomas J.

2008-01-01

A test loop using NaK as the working fluid is presently in use to study material compatibility effects on various components that comprise a possible nuclear reactor design for use on the lunar surface. A DC electromagnetic (EM) pump has been designed and implemented as a means of actively controlling the NaK flow rate through the system and an EM flow sensor is employed to monitor the developed flow rate. These components allow for the matching of the flow rate conditions in test loops with those that would be found in a full-scale surface-power reactor. The design and operating characteristics of the EM pump and flow sensor are presented. In the EM pump, current is applied to a set of electrodes to produce a Lorentz body force in the fluid. A measurement of the induced voltage (back-EMF) in the flow sensor provides the means of monitoring flow rate. Both components are compact, employing high magnetic field strength neodymium magnets thermally coupled to a water-cooled housing. A vacuum gap limits the heat transferred from the high temperature NaK tube to the magnets and a magnetically-permeable material completes the magnetic circuit. The pump is designed to produce a pressure rise of 34.5 kPa, and the flow sensor's predicted output is roughly 20 mV at the loop's nominal flow rate of 0.114 m3/hr.

Flow Components in a NaK Test Loop Designed to Simulate Conditions in a Nuclear Surface Power Reactor

NASA Technical Reports Server (NTRS)

Polzin, Kurt A.; Godfroy, Thomas J.

2008-01-01

A test loop using NaK as the working fluid is presently in use to study material compatibility effects on various components that comprise a possible nuclear reactor design for use on the lunar surface. A DC electromagnetic (EM) pump has been designed and implemented as a means of actively controlling the NaK flow rate through the system and an EM flow sensor is employed to monitor the developed flow rate. These components allow for the matching of the flow rate conditions in test loops with those that would be found in a full-scale surface-power reactor. The design and operating characteristics of the EM pump and flow sensor are presented. In the EM pump, current is applied to a set of electrodes to produce a Lorentz body force in the fluid. A measurement of the induced voltage (back-EMF) in the flow sensor provides the means of monitoring flow rate. Both components are compact, employing high magnetic field strength neodymium magnets thermally coupled to a water-cooled housing. A vacuum gap limits the heat transferred from the high temperature NaK tube to the magnets and a magnetically-permeable material completes the magnetic circuit. The pump is designed to produce a pressure rise of 5 psi, and the flow sensor's predicted output is roughly 20 mV at the loop's nominal flow rate of 0.5 GPM.

A numerical study of the thermal stability of low-lying coronal loops

NASA Technical Reports Server (NTRS)

Klimchuk, J. A.; Antiochos, S. K.; Mariska, J. T.

1986-01-01

The nonlinear evolution of loops that are subjected to a variety of small but finite perturbations was studied. Only the low-lying loops are considered. The analysis was performed numerically using a one-dimensional hydrodynamical model developed at the Naval Research Laboratory. The computer codes solve the time-dependent equations for mass, momentum, and energy transport. The primary interest is the active region filaments, hence a geometry appropriate to those structures was considered. The static solutions were subjected to a moderate sized perturbation and allowed to evolve. The results suggest that both hot and cool loops of the geometry considered are thermally stable against amplitude perturbations of all kinds.

Energy Conversion Loop: A Testbed for Nuclear Hybrid Energy Systems Use in Biomass Pyrolysis

NASA Astrophysics Data System (ADS)

Verner, Kelley M.

Nuclear hybrid energy systems are a possible solution for contemporary energy challenges. Nuclear energy produces electricity without greenhouse gas emissions. However, nuclear power production is not as flexible as electrical grids demand and renewables create highly variable electricity. Nuclear hybrid energy systems are able to address both of these problems. Wasted heat can be used in processes such as desalination, hydrogen production, or biofuel production. This research explores the possible uses of nuclear process heat in bio-oil production via biomass pyrolysis. The energy conversion loop is a testbed designed and built to mimic the heat from a nuclear reactor. Small scale biomass pyrolysis experiments were performed and compared to results from the energy conversion loop tests to determine future pyrolysis experimentation with the energy conversion loop. Further improvements must be made to the energy conversion loop before more complex experiments may be performed. The current conditions produced by the energy conversion loop are not conducive for current biomass pyrolysis experimentation.tion.

The pressure and energy balance of the cool corona over sunspots

NASA Technical Reports Server (NTRS)

Foukal, P. V.

1976-01-01

The 22 largest sunspots observed with the Skylab SO55 spectrometer are studied for a relation between their EUV radiation and their umbral size or magnetic classification. The ultimate goal is to determine why the coronal plasma is so cool over a sunspot and how this cool plasma manages to support itself against gravity. Based on the time behavior of the EUV emission, a steady-state model is developed for the pressure and energy balance of the cool coronal-plasma loops over the spots. Analysis of the temperature structure in a typical loop indicates that the loop is exceedingly well insulated from the outside corona, that its energy balance is determined purely by internal heating and cooling processes, and that a heat input of about 0.0001 erg/cu cm per sec is required along the full length of the loop. It is proposed that: (1) coronal material flows steadily across the field lines at the tops of the loops and falls downward along both sides under gravity; (2) the corona is heated by mechanical-energy transport across the very thin transition region immediately over network-cell interiors; and (3) strong magnetic fields tend to inhibit mechanical-energy dissipation in the corona.

The early history of the closed loop fiber optic gyro and derivative sensors at McDonnell Douglas, Blue Road Research and Columbia Gorge Research

NASA Astrophysics Data System (ADS)

Udd, Eric

2016-05-01

On September 29, 1977 the first written disclosure of a closed loop fiber optic gyro was witnessed and signed off by four people at McDonnell Douglas Astronautics Company in Huntington Beach, California. Over the next ten years a breadboard demonstration unit, and several prototypes were built. In 1987 the fundamental patent for closed loop operation began a McDonnell Douglas worldwide licensing process. Internal fiber optic efforts were redirected to derivative sensors and inventions. This included development of acoustic, strain and distributed sensors as well as a Sagnac interferometer based secure fiber optic communication system and the new field of fiber optic smart structures. This paper provides an overview of these activities and transitions.

Non-Toxic, Low-Freezing, Drop-In Replacement Heat Transfer Fluids

NASA Technical Reports Server (NTRS)

Cutbirth, J. Michael

2012-01-01

A non-toxic, non-flammable, low-freezing heat transfer fluid is being developed for drop-in replacement within current and future heat transfer loops currently using water or alcohol-based coolants. Numerous water-soluble compounds were down-selected and screened for toxicological, physical, chemical, compatibility, thermodynamic, and heat transfer properties. Two fluids were developed, one with a freezing point near 0 C, and one with a suppressed freezing point. Both fluids contain an additive package to improve material compatibility and microbial resistance. The optimized sub-zero solution had a freezing point of 30 C, and a freezing volume expansion of 10-percent of water. The toxicity of the solutions was experimentally determined as LD(50) greater than 5g/kg. The solutions were found to produce minimal corrosion with materials identified by NASA as potentially existing in secondary cooling loops. Thermal/hydrodynamic performance exceeded that of glycol-based fluids with comparable freezing points for temperatures Tf greater than 20 C. The additive package was demonstrated as a buffering agent to compensate for CO2 absorption, and to prevent microbial growth. The optimized solutions were determined to have physically/chemically stable shelf lives for freeze/thaw cycles and longterm test loop tests.

Dissolved oxygen control and monitoring implementation in the liquid lead bismuth eutectic loop: HELIOS

NASA Astrophysics Data System (ADS)

Nam, Hyo On; Lim, Jun; Han, Dong Yoon; Hwang, Il Soon

2008-06-01

A 12 m tall LBE coolant loop, named as HELIOS, has been developed by thermal-hydraulic scaling of the PEACER-300MWe. Thermo-hydraulic experiment and materials test are the principal purposes of HELIOS operation. In this study, an yttria stabilized zirconia (YSZ) based oxygen sensor that was hermetically sealed for long-term applications using the electromagnetically swaged metal-ceramic joining method, have been developed for high temperature oxygen control application over a long period of time. The rugged electrode design has been calibrated to absolute metal-oxide equilibrium by using a first principle of detecting pure metal-oxide transition using electrochemical impedance spectroscopy (EIS). During the materials tests in HELIOS, dissolved oxygen concentration was administered at the intended condition of 10 -6 wt% by direct gas bubbling with Ar + 4%H 2, Ar + 5%O 2 and/or pure Ar while corrosion tests were conducted for up to 1000 h with inspection after each 333 h. During the total 1000 h corrosion test, oxygen concentration was measured by oxygen sensor. The result confirmed that the direct gas bubbling method is a viable and practical option for controlling oxygen concentration in large loops including HELIOS.

First Experiences with the New Chalmers Gasifier

NASA Astrophysics Data System (ADS)

Thunman, H.; Seemann, M. C.

During summer 2007 a 2-6 MWth indirect gasification section was integrated into the loop of the existing 82➀2 MWth circulating fluidized bed boiler at Chalmers University. With help of a particle distributor the gasification unit is connected to the loop after the cyclone. Hot bed material entrained from the boiler is so transferred to the gasifier providing the heat for the production of a nearly nitrogen free product gas. Non-gasified char is returned together with the bed material into the boiler and converted. Biomass can be fed into both sections; the boiler and the gasifier. The gasification is separated from the boiler via two loop seals and a particle distributer, directing particles either back to the boiler or into the gasification section. For that reason the CFB boiler can be operated even after the retrofit independently, just like before, or in combined combustion/gasification mode. This possibility keeps the risk for a retrofit low. As, furthermore, the investment costs for the integration are considerably lower than standalone gasification units of that size, the retrofit is an easy way to extend the potential of a CFB Boiler towards bi- and tri-generation (heat, power, fuel) and enter new markets.

Equilibrium, metastability, and hysteresis in a model spin-crossover material with nearest-neighbor antiferromagnetic-like and long-range ferromagnetic-like interactions

DOE PAGES

Rikvold, Per Arne; Brown, Gregory; Miyashita, Seiji; ...

2016-02-16

Phase diagrams and hysteresis loops were obtained by Monte Carlo simulations and a mean- field method for a simplified model of a spin-crossovermaterialwith a two-step transition between the high-spin and low-spin states. This model is a mapping onto a square-lattice S = 1/2 Ising model with antiferromagnetic nearest-neighbor and ferromagnetic Husimi-Temperley ( equivalent-neighbor) long-range interactions. Phase diagrams obtained by the two methods for weak and strong long-range interactions are found to be similar. However, for intermediate-strength long-range interactions, the Monte Carlo simulations show that tricritical points decompose into pairs of critical end points and mean-field critical points surrounded by horn-shapedmore » regions of metastability. Hysteresis loops along paths traversing the horn regions are strongly reminiscent of thermal two-step transition loops with hysteresis, recently observed experimentally in several spin-crossover materials. As a result, we believe analogous phenomena should be observable in experiments and simulations for many systems that exhibit competition between local antiferromagnetic-like interactions and long-range ferromagnetic-like interactions caused by elastic distortions.« less

Levitation of superconducting composites

NASA Technical Reports Server (NTRS)

Chiang, C. K.; Turchinskaya, M.; Swartzendruber, L. J.; Shull, R. D.; Bennett, L. H.

1991-01-01

The inverse levitation of a high temperature superconductor polymer composite consisting of powdered quench melt growth Ba2YCu3O(7-delta) and cyanoacrylate is reported. Magnetic hysteresis loop measurements for the composite are compared to those measured for the bulk material prior to powdering. Differences in the flux pining capability between the two material forms are small but significant.

Improved vortex reactor system

DOEpatents

Diebold, James P.; Scahill, John W.

1995-01-01

An improved vortex reactor system for affecting fast pyrolysis of biomass and Refuse Derived Fuel (RDF) feed materials comprising: a vortex reactor having its axis vertically disposed in relation to a jet of a horizontally disposed steam ejector that impels feed materials from a feeder and solids from a recycle loop along with a motive gas into a top part of said reactor.

Development of a Thin Film Primary Surface Heat Exchanger for Advanced Power Cycles

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

Allison, Tim; Beck, Griffin; Bennett, Jeffrey

This project objective is to develop a high-temperature design upgrade for an existing primary surface heat exchanger so that the redesigned hardware is capable of operation in CO 2 at temperatures up to 1,510°F (821°C) and pressure differentials up to 130 psi (9 bar). The heat exchanger is proposed for use as a recuperator in an advanced low-pressure oxy-fuel Brayton cycle that is predicted to achieve over 50% thermodynamic efficiency, although the heat exchanger could also be used in other high-temperature, low-differential pressure cycles. This report describes the progress to date, which includes continuing work performed to select and testmore » new candidate materials for the recuperator redesign, final mechanical and thermal performance analysis results of various redesign concepts, and the preliminary design of a test loop for the redesigned recuperator including a budgetary estimate for detailed test loop design, procurement, and test operation. A materials search was performed in order to investigate high-temperature properties of many candidate materials, including high-temperature strength and nickel content. These properties were used to rank the candidate materials, resulting in a reduced list of nine materials for corrosion testing. Multiple test rigs were considered and analyzed for short-term corrosion testing and Thermal Gravimetric Analysis (TGA) was selected as the most cost-effective option for evaluating corrosion resistance of the candidate materials. In addition, tantalum, niobium, and chromium coatings were identified as potential options for increased corrosion resistance. The test results show that many materials exhibit relatively low weight gain rates, and that niobium and tantalum coatings may improve corrosion resistance for many materials, while chromium coatings appear to oxidize and debond quickly. Metallurgical analysis of alloys was also performed, showing evidence of intergranular attack in 282 that may cause long-term reliability problems in CO 2 service at these temperatures. However, long-term testing in a flowing environment is recommended in order to understand accurately the severity of the attack. Detailed economic modeling of the existing air cycle recuperator and CO 2 cycle recuperator options was also completed, including costs for material, fabrication, fuel, maintenance, and operation. The analysis results show that the increased capital cost for high-temperature materials may be offset by higher cycle efficiencies, decreasing the overall lifetime cost of the system. The economic analysis also examines costs associated with increased pressure drop and material changes for two redesign options. These results show that, even with slightly reduced performance and/or higher material costs, the lifetime cost per energy production may still be reduced by over 12%. The existing recuperator design information was provided by Solar Turbines, Inc. via several models, drawings, and design handoff meetings. Multiple fluid/thermal and structural models were created in order to analyze critical recuperator performance and mechanical strength in critical areas throughout the redesign process. These models were analyzed for a baseline condition (consistent with current Mercury 50 operation) for validation purposes. Results are presented for heat transfer coefficients and pressure drops, matching well with the existing operational data. Simulation of higher-temperature CO 2 conditions was also performed, showing a slight expected increase in both heat transfer and pressure drop. Mechanical analysis results for critical areas on the cross-flow and counter-flow sheets have also been obtained for air and CO 2 cases. These results show similar stresses in both cases but significantly reduced safety factors for the CO 2 case due to reduced yield and creep rupture strengths of alloy 625 at the higher temperatures. A concept brainstorm session and initial down-selection were completed in order to identify promising redesign options for further analysis. Detailed analysis of all promising redesign options was performed via finite element and computational fluid dynamic simulations in order to characterize mechanical and thermal-fluid performance of each option. These options included material change, various sheet thickness configurations, pitch and phasing of cross-flow and counter-flow sheets, and separator sheets. The analysis results have identified two viable redesign options that maintain existing safety margins optimally through a material change to Haynes 282 and (A) sheet thickness increases of 40% on the counter-flow sheet and 75% on the hot side cross-flow corrugation sheet or (B) addition of a separator sheet in the counter-flow section while maintaining the original counter-flow sheet thickness and increasing the cross-flow corrugation sheet thickness by 90% to account for the increase in cell height. While both options satisfy mechanical stress constraints, the separator sheet design has a higher part count, slightly reduced heat transfer, and slightly higher pressure drop than the first option and is not preferred. Finally, several test loop concepts have been developed for different full-scale and reduced-scale recuperator testing options. For each option, various loop components, such as heat exchangers, valves, heaters, and compressors, were evaluated in an effort to maximize utilization of existing resources. All concepts utilize an existing 3-MW CO 2 compressor, heater, and loop coolers, but the concepts vary by incorporating different amounts of new equipment for achieving various flow rates (all concepts operate at design pressure and temperature). The third concept achieves a 1 kg/s test without purchasing any costly equipment (coolers, heaters, blowers, etc.). Since the stacked cell design of the recuperator results in the same flow conditions at each core cell (even for a reduced-scale test). Thus, test loop Concept #3 was selected for the preliminary design. This loop design is detailed within the report, culminating in a budgetary estimate of $1,013,000.00 for the detailed design, construction, commissioning, and operation of a high-temperature recuperator test loop.« less

Closed-Loop Neuromorphic Benchmarks

PubMed Central

Stewart, Terrence C.; DeWolf, Travis; Kleinhans, Ashley; Eliasmith, Chris

2015-01-01

Evaluating the effectiveness and performance of neuromorphic hardware is difficult. It is even more difficult when the task of interest is a closed-loop task; that is, a task where the output from the neuromorphic hardware affects some environment, which then in turn affects the hardware's future input. However, closed-loop situations are one of the primary potential uses of neuromorphic hardware. To address this, we present a methodology for generating closed-loop benchmarks that makes use of a hybrid of real physical embodiment and a type of “minimal” simulation. Minimal simulation has been shown to lead to robust real-world performance, while still maintaining the practical advantages of simulation, such as making it easy for the same benchmark to be used by many researchers. This method is flexible enough to allow researchers to explicitly modify the benchmarks to identify specific task domains where particular hardware excels. To demonstrate the method, we present a set of novel benchmarks that focus on motor control for an arbitrary system with unknown external forces. Using these benchmarks, we show that an error-driven learning rule can consistently improve motor control performance across a randomly generated family of closed-loop simulations, even when there are up to 15 interacting joints to be controlled. PMID:26696820

A study on single lane-change manoeuvres for determining rearward amplification of multi-trailer articulated heavy vehicles with active trailer steering systems

NASA Astrophysics Data System (ADS)

Wang, Qiushi; He, Yuping

2016-01-01

The Society of Automotive Engineers issued a test procedure, SAE-J2179, to determine the rearward amplification (RA) of multi-trailer articulated heavy vehicles (MTAHVs). Built upon the procedure, the International Organization for Standardization released the test manoeuvres, ISO-14791, for evaluating directional performance of MTAHVs. For the RA measures, ISO-14791 recommends two single lane-change manoeuvres: (1) an open-loop procedure with a single sine-wave steering input; and (2) a closed-loop manoeuvre with a single sine-wave lateral acceleration input. For an articulated vehicle with active trailer steering (ATS), the RA measure in lateral acceleration under the open-loop manoeuvre was not in good agreement with that under the closed-loop manoeuvre. This observation motivates the research on the applicability of the two manoeuvres for the RA measures of MTAHVs with ATS. It is reported that transient response under the open-loop manoeuvre often leads to asymmetric curve of tractor lateral acceleration [Winkler CB, Fancher PS, Bareket Z, Bogard S, Johnson G, Karamihas S, Mink C. Heavy vehicle size and weight - test procedures for minimum safety performance standards. Final technical report, NHTSA, US DOT, contract DTNH22-87-D-17174, University of Michigan Transportation Research Institute, Report No. UMTRI-92-13; 1992]. To explore the effect of the transient response, a multiple cycle sine-wave steering input (MCSSI) manoeuvre is proposed. Simulation demonstrates that the steady-state RA measures of an MTAHV with and without ATS under the MCSSI manoeuvre are in excellent agreement with those under the closed-loop manoeuvre. It is indicated that between the two manoeuvres by ISO-14791, the closed-loop manoeuvre is more applicable for determining the RA measures of MTAHVs with ATS.

Prediction methodologies for target scene generation in the aerothermal targets analysis program (ATAP)

NASA Astrophysics Data System (ADS)

Hudson, Douglas J.; Torres, Manuel; Dougherty, Catherine; Rajendran, Natesan; Thompson, Rhoe A.

2003-09-01

The Air Force Research Laboratory (AFRL) Aerothermal Targets Analysis Program (ATAP) is a user-friendly, engineering-level computational tool that features integrated aerodynamics, six-degree-of-freedom (6-DoF) trajectory/motion, convective and radiative heat transfer, and thermal/material response to provide an optimal blend of accuracy and speed for design and analysis applications. ATAP is sponsored by the Kinetic Kill Vehicle Hardware-in-the-Loop Simulator (KHILS) facility at Eglin AFB, where it is used with the CHAMP (Composite Hardbody and Missile Plume) technique for rapid infrared (IR) signature and imagery predictions. ATAP capabilities include an integrated 1-D conduction model for up to 5 in-depth material layers (with options for gaps/voids with radiative heat transfer), fin modeling, several surface ablation modeling options, a materials library with over 250 materials, options for user-defined materials, selectable/definable atmosphere and earth models, multiple trajectory options, and an array of aerodynamic prediction methods. All major code modeling features have been validated with ground-test data from wind tunnels, shock tubes, and ballistics ranges, and flight-test data for both U.S. and foreign strategic and theater systems. Numerous applications include the design and analysis of interceptors, booster and shroud configurations, window environments, tactical missiles, and reentry vehicles.

Compatibility of Space Nuclear Power Plant Materials in an Inert He/Xe Working Gas Containing Reactive Impurities

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

MM Hall

2006-01-31

A major materials selection and qualification issue identified in the Space Materials Plan is the potential for creating materials compatibility problems by combining dissimilar reactor core, Brayton Unit and other power conversion plant materials in a recirculating, inert He/Xe gas loop containing reactive impurity gases. Reported here are results of equilibrium thermochemical analyses that address the compatibility of space nuclear power plant (SNPP) materials in high temperature impure He gas environments. These studies provide early information regarding the constraints that exist for SNPP materials selection and provide guidance for establishing test objectives and environments for SNPP materials qualification testing.

RCD+: Fast loop modeling server.

PubMed

López-Blanco, José Ramón; Canosa-Valls, Alejandro Jesús; Li, Yaohang; Chacón, Pablo

2016-07-08

Modeling loops is a critical and challenging step in protein modeling and prediction. We have developed a quick online service (http://rcd.chaconlab.org) for ab initio loop modeling combining a coarse-grained conformational search with a full-atom refinement. Our original Random Coordinate Descent (RCD) loop closure algorithm has been greatly improved to enrich the sampling distribution towards near-native conformations. These improvements include a new workflow optimization, MPI-parallelization and fast backbone angle sampling based on neighbor-dependent Ramachandran probability distributions. The server starts by efficiently searching the vast conformational space from only the loop sequence information and the environment atomic coordinates. The generated closed loop models are subsequently ranked using a fast distance-orientation dependent energy filter. Top ranked loops are refined with the Rosetta energy function to obtain accurate all-atom predictions that can be interactively inspected in an user-friendly web interface. Using standard benchmarks, the average root mean squared deviation (RMSD) is 0.8 and 1.4 Å for 8 and 12 residues loops, respectively, in the challenging modeling scenario in where the side chains of the loop environment are fully remodeled. These results are not only very competitive compared to those obtained with public state of the art methods, but also they are obtained ∼10-fold faster. © The Author(s) 2016. Published by Oxford University Press on behalf of Nucleic Acids Research.

Numerical investigation of the relationship between magnetic stiffness and minor loop size in the HTS levitation system

NASA Astrophysics Data System (ADS)

Yang, Yong; Li, Chengshan

2017-10-01

The effect of minor loop size on the magnetic stiffness has not been paid attention to by most researchers in experimental and theoretical studies about the high temperature superconductor (HTS) magnetic levitation system. In this work, we numerically investigate the average magnetic stiffness obtained by the minor loop traverses Δz (or Δx) varying from 0.1 mm to 2 mm in zero field cooling and field cooling regimes, respectively. The approximate values of the magnetic stiffness with zero traverse are obtained using the method of linear extrapolation. Compared with the average magnetic stiffness gained by any minor loop traverse, these approximate values are Not always close to the average magnetic stiffness produced by the smallest size of minor loops. The relative deviation ranges of average magnetic stiffness gained by the usually minor loop traverse (1 or 2 mm) are presented by the ratios of approximate values to average stiffness for different moving processes and two typical cooling conditions. The results show that most of average magnetic stiffness are remarkably influenced by the sizes of minor loop, which indicates that the magnetic stiffness obtained by a single minor loop traverse Δ z or Δ x, for example, 1 or 2 mm, can be generally caused a large deviation.

Virtual Electrochemical Strain Microscopy of Polycrystalline LiCoO2 Films

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

Chung, Ding-wen; Balke, Nina; Kalinin, Sergei V

2011-01-01

A recently developed technique, electrochemical strain microscopy (ESM), utilizes the strong coupling between ionic current and anisotropic volumetric chemical expansion of lithium-ion electrode materials to dynamically probe the sub-one-hundred? nm inter-facial kinetic intercalation properties. A numerical technique based on the finite element method was developed to analyze the underlying physics that govern the ESM signal generation and establish relations to battery performance. The performed analysis demonstrates that the diffusion path within a thin film is tortuous and the extent of lithium diffusion into the electrode is dependent on the SPM-tip-imposed overpotential frequency. The detected surface actuation gives rise to themore » development of an electromechanical hysteresis loop whose shape is dependent on grain size and overpotential frequency. Shape and tilting angle of the loop are classified into low and high frequency regimes, separated by a transition frequency which is also a function of lithium diffusivity and grain size, f{sub T} = D//{sup 2}. Research shows that the crystallographic orientation of the surface actuated grain has a significant impact on the shape of the loop. The polycrystalline crystallographic orientation of the grains induces a diffusion path network in the electrode which impacts on the mechanical reliability of the battery. Simulations demonstrate that continuous battery cycling results in a cumulative capacity loss as a result of the hysteric non-reversible lithium intercalation. Furthermore, results suggest that ESM has the capability to infer the local out-of-plane lithium diffusivity and the out-of-plane contribution to Vegard tensor.« less

Virtual Electrochemical Strain Microscopy of Polycrystalline LiCoO2 Films

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

Chung, Ding-Wen; Balke, Nina; Kalinin, Sergei V.

2011-08-03

A recently developed technique, electrochemical strain microscopy (ESM), utilizes the strong coupling between ionic current and anisotropic volumetric chemical expansion of lithium-ion electrode materials to dynamically probe the sub-one-hundred? nm inter-facial kinetic intercalation properties. A numerical technique based on the finite element method was developed to analyze the underlying physics that govern the ESM signal generation and establish relations to battery performance. The performed analysis demonstrates that the diffusion path within a thin film is tortuous and the extent of lithium diffusion into the electrode is dependent on the SPM-tip-imposed overpotential frequency. The detected surface actuation gives rise to themore » development of an electromechanical hysteresis loop whose shape is dependent on grain size and overpotential frequency. Shape and tilting angle of the loop are classified into low and high frequency regimes, separated by a transition frequency which is also a function of lithium diffusivity and grain size, f T = D/l₂. Research shows that the crystallographic orientation of the surface actuated grain has a significant impact on the shape of the loop. The polycrystalline crystallographic orientation of the grains induces a diffusion path network in the electrode which impacts on the mechanical reliability of the battery. Simulations demonstrate that continuous battery cycling results in a cumulative capacity loss as a result of the hysteric non-reversible lithium intercalation. Furthermore, results suggest that ESM has the capability to infer the local out-of-plane lithium diffusivity and the out-of-plane contribution to Vegard tensor.« less

TREAT Neutronics Analysis of Water-Loop Concept Accommodating LWR 9-rod Bundle

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

Hill, Connie M.; Woolstenhulme, Nicolas E.; Parry, James R.

Abstract. Simulation of a variety of transient conditions has been successfully achieved in the Transient Reactor Test (TREAT) facility during operation between 1959 and 1994 to support characterization and safety analysis of nuclear fuels and materials. A majority of previously conducted tests were focused on supporting sodium-cooled fast reactor (SFR) designs. Experiments evolved in complexity. Simulation of thermal-hydraulic conditions expected to be encountered by fuels and materials in a reactor environment was realized in the development of TREAT sodium loop experiment vehicles. These loops accommodated up to 7-pin fuel bundles and served to simulate more closely the reactor environment whilemore » safely delivering large quantities of energy into the test specimen. Some of the immediate TREAT restart operations will be focused on testing light water reactor (LWR) accident tolerant fuels (ATF). Similar to the sodium loop objectives, a water loop concept, developed and analyzed in the 1990’s, aimed at achieving thermal-hydraulic conditions encountered in commercial power reactors. The historic water loop concept has been analyzed in the context of a reactivity insertion accident (RIA) simulation for high burnup LWR 2-pin and 3-pin fuel bundles. Findings showed sufficient energy could be deposited into the specimens for evaluation. Similar results of experimental feasibility for the water loop concept (past and present) have recently been obtained using MCNP6.1 with ENDF/B-VII.1 nuclear data libraries. The old water loop concept required only two central TREAT core grid spaces. Preparation for future experiments has resulted in a modified water loop conceptual design designated the TREAT water environment recirculating loop (TWERL). The current TWERL design requires nine TREAT core grid spaces in order to place the water recirculating pump under the TREAT core. Due to the effectiveness of water moderation, neutronics analysis shows that removal of seven additional TREAT fuel elements to facilitate the experiment will not inhibit the ability to successfully simulate a RIA for the 2-pin or 3-pin bundle. This new water loop design leaves room for accommodating a larger fuel pin bundle than previously analyzed. The 7-pin fuel bundle in a hexagonal array with similar spacing of fuel pins in a SFR fuel assembly was considered the minimum needed for one central fuel pin to encounter the most correct thermal conditions. The 9-rod fuel bundle in a square array similar in spacing to pins in a LWR fuel assembly would be considered the LWR equivalent. MCNP analysis conducted on a preliminary LWR 9-rod bundle design shows that sufficient energy deposition into the central pin can be achieved well within range to investigate fuel and cladding performance in a simulated RIA. This is achieved by surrounding the flow channel with an additional annulus of water. Findings also show that a highly significant increase in TREAT to specimen power coupling factor (PCF) within the central pin can be achieved by surrounding the experiment with one to two rings of TREAT upgrade fuel assemblies. The experiment design holds promise for the performance evaluation of PWR fuel at extremely high burnup under similar reactor environment conditions.« less

Understanding social forces involved in diabetes outcomes: a systems science approach to quality-of-life research.

PubMed

Lounsbury, David W; Hirsch, Gary B; Vega, Chawntel; Schwartz, Carolyn E

2014-04-01

The field of quality-of-life (QOL) research would benefit from learning about and integrating systems science approaches that model how social forces interact dynamically with health and affect the course of chronic illnesses. Our purpose is to describe the systems science mindset and to illustrate the utility of a system dynamics approach to promoting QOL research in chronic disease, using diabetes as an example. We build a series of causal loop diagrams incrementally, introducing new variables and their dynamic relationships at each stage. These causal loop diagrams demonstrate how a common set of relationships among these variables can generate different disease and QOL trajectories for people with diabetes and also lead to a consideration of non-clinical (psychosocial and behavioral) factors that can have implications for program design and policy formulation. The policy implications of the causal loop diagrams are discussed, and empirical next steps to validate the diagrams and quantify the relationships are described.

Magnetoelastic Properties of Magnetic Thin Films Using the Magnetooptic Kerr Effect

NASA Astrophysics Data System (ADS)

Mayo, Elizabeth; Lederman, David

1998-03-01

The magnetoelastic properties of Co and Fe thin films were measured using the magnetooptic Kerr effect (MOKE). Films were grown via magnetron sputtering on thin mica substrates. Magnetization loops were measured using MOKE with the magnetic field along different in-plane directions. Subsequently, the samples were mounted on a cylindrical sample holder, which imposed a well-defined strain to the film. This caused the magnetization loops to change dramatically due to the magnetoelastic coefficient of the thin film materials. The effects of the surface roughness and film thickness will also be discussed.

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

Not Available

Oberlin Colleges Adam Joseph Lewis Center for Environmental Studies is a high-performance building featuring an expansive photovoltaic system and a closed-loop groundwater heat pump system. Designers incorporated energy-efficient components and materials that are local, non-toxic, and durable.

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

None

Oberlin College's Adam Joseph Lewis Center for Environmental Studies is a high-performance building featuring an expansive photovoltaic system and a closed-loop groundwater heat pump system. Designers incorporated energy-efficient components and materials that are local, non-toxic, and durable.

Microstructural evolution of NF709 (20Cr–25Ni–1.5MoNbTiN) under neutron irradiation

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

Kim, Byoungkoo; Tan, Lizhen; Xu, C.

In this study, because of its superior creep and corrosion resistance as compared with general austenitic stainless steels, NF709 has emerged as a candidate structural material for advanced nuclear reactors. To obtain fundamental information about the radiation resistance of this material, this study examined the microstructural evolution of NF709 subjected to neutron irradiation to 3 displacements per atom at 500 °C. Transmission electron microscopy, scanning electron microscopy, and high-energy x-ray diffraction were employed to characterize radiation-induced segregation, Frank loops, voids, as well as the formation and reduction of precipitates. Radiation hardening of ~76% was estimated by nanoindentation, approximately consistent withmore » the calculation according to the dispersed barrier-hardening model, suggesting Frank loops as the primary hardening source.« less

Microstructural evolution of NF709 (20Cr–25Ni–1.5MoNbTiN) under neutron irradiation

DOE PAGES

Kim, Byoungkoo; Tan, Lizhen; Xu, C.; ...

2015-12-30

In this study, because of its superior creep and corrosion resistance as compared with general austenitic stainless steels, NF709 has emerged as a candidate structural material for advanced nuclear reactors. To obtain fundamental information about the radiation resistance of this material, this study examined the microstructural evolution of NF709 subjected to neutron irradiation to 3 displacements per atom at 500 °C. Transmission electron microscopy, scanning electron microscopy, and high-energy x-ray diffraction were employed to characterize radiation-induced segregation, Frank loops, voids, as well as the formation and reduction of precipitates. Radiation hardening of ~76% was estimated by nanoindentation, approximately consistent withmore » the calculation according to the dispersed barrier-hardening model, suggesting Frank loops as the primary hardening source.« less

Comparing Looping Teacher-Assigned and Traditional Teacher-Assigned Student Achievement Scores

ERIC Educational Resources Information Center

Lloyd, Melissa C.

2014-01-01

A problem in many elementary schools is determining which teacher assignment strategy best promotes the academic progress of students. To find and implement educational practices that address the academic needs of all learners, schools need research-based data focusing on the 2 teacher assignment strategies: looping assignment (LA) and traditional…

TOP DOWN CONTROL OF THE MICROBIAL LOOP IN ESTUARINE PHYTOPLANKTON

EPA Science Inventory

Top Down Control of the Microbial Loop in Estuarine Plankton (Abstract). To be presented at the 16th Biennial Conference of the Estuarine Research Foundation, ERF 2001: An Estuarine Odyssey, 4-8 November 2001, St. Pete Beach, FL. 1 p. (ERL,GB R846).

We examined the effects...

Toxin MqsR Cleaves Single-Stranded mRNA with Various 5 Ends

DTIC Science & Technology

2016-08-24

either protein ORIGINAL RESEARCH Toxin MqsR cleaves single- stranded mRNA with various 5’ ends Nityananda Chowdhury1,*, Brian W. Kwan1,*, Louise C...in which a single 5′- GCU site was predicted to be single- stranded (ssRNA), double- stranded (dsRNA), in the loop of a stem - loop (slRNA), or in a...single- stranded 5′- GCU sites since cleavage was approximately 20- fold higher than cleavage seen with the 5′- GCU site in the stem - loop and

Bit Synchronization with Cross Spectrum Synchronization Loop. Attachment III.

DTIC Science & Technology

1981-10-01

AO-AII 1 ICMCR AAE~C BIT SYNCHRONIZATION WITH CROSS SPECTRUM SYNCHRONIZATION LOOP .A_ ETC(U) O’ASFE CT A1 R A MA A 6. A C LINDSEY, C M CHIE NOOOI𔃾...BUR[AU OF STANOARDS 196.- A I~I -I I I Yinwoa on. IAoalt [ S0Box0 2793D, Pasadena Calif 91105 82 03 09098 I7- ATTACHMENT III BIT SYNCHRONIZATION WITH...CROSS SPECTRUM SYNCHRONIZATION LOOP I ’I PREPARED FOR NAVAL RESEARCH LABORATORY WASHINGTON, D.C. 20375 .Jr TECHNICAL MONITOR: MR. MORT FRANK I CONTRACT

Integrated Collaborative Model in Research and Education with Emphasis on Small Satellite Technology

DTIC Science & Technology

1996-01-01

feedback; the number of iterations in a complete iteration is referred to as loop depth or iteration depth, g (i). A data packet or packet is data...loop depth, g (i)) is either a finite (constant or variable) or an infinite value. 1) Finite loop depth, variable number of iterations Some problems...design time. The time needed for the first packet to leave and a new initial data to be introduced to the iteration is min(R * ( g (k) * (N+I) + k-1

A model for technology assessment as applied to closed loop infusion systems. Technology Assessment Task Force of the Society of Critical Care Medicine.

PubMed

Jastremski, M; Jastremski, C; Shepherd, M; Friedman, V; Porembka, D; Smith, R; Gonzales, E; Swedlow, D; Belzberg, H; Crass, R

1995-10-01

To test a model for the assessment of critical care technology on closed loop infusion control, a technology that is in its early stages of development and testing on human subjects. A computer-assisted search of the English language literature and reviews of the gathered data by experts in the field of closed loop infusion control systems. Studies relating to closed loop infusion control that addressed one or more of the questions contained in our technology assessment template were analyzed. Study design was not a factor in article selection. However, the lack of well-designed clinical outcome studies was an important factor in determining our conclusions. A focus person summarized the data from the selected studies that related to each of the assessment questions. The preliminary data summary developed by the focus person was further analyzed and refined by the task force. Experts in closed loop systems were then added to the group to review the summary provided by the task force. These experts' comments were considered by the task force and this final consensus report was developed. Closed loop system control is a technological concept that may be applicable to several aspects of critical care practice. This is a technology in the early stages of evolution and much more research and data are needed before its introduction into usual clinical practice. Furthermore, each specific application and each device for each application (e.g., nitroprusside infusion, ventilator adjustment), although based on the same technological concept, are sufficiently different in terms of hardware and computer algorithms to require independent validation studies. Closed loop infusion systems may have a role in critical care practice. However, for most applications, further development is required to move this technology from the innovation phase to the point where it can be evaluated so that its role in critical car practice can be defined. Each application of closed loop infusion systems must be independently validated by appropriately designed research studies. Users should be provided with the clinical parameters driving each closed loop system so that they can ensure that it agrees with their opinion of acceptable medical practice. Clinical researchers and leaders in industry should collaborate to perform the scientifically valid, outcome-based research that is necessary to evaluate the effect of this new technology. The original model we developed for technology assessment required the addition of several more questions to produce a complete analysis of an emerging technology. An emerging technology should be systematically assessed (using a model such as the model developed by the Society of Critical Care Medicine), before its introduction into clinical practice in order to provide a focus for human outcome validation trials and to minimize the possibility of widespread use of an unproven technology.

Flow quality studies of the NASA Lewis Research Center Icing Research Tunnel

NASA Technical Reports Server (NTRS)

Arrington, E. Allen; Pickett, Mark T.; Sheldon, David W.

1994-01-01

A series of studies have been conducted to determine the flow quality in the NASA Lewis Icing Research Tunnel. The primary purpose of these studies was to document airflow characteristics, including flow angularity, in the test section and tunnel loop. A vertically mounted rake was used to survey total and static pressure and two components of flow angle at three axial stations within the test section (test section inlet, test plane, and test section exit; 15 survey stations total). This information will be used to develop methods of improving the aerodynamic and icing characteristics within the test section. The data from surveys made in the tunnel loop were used to determine areas where overall tunnel flow quality and efficiency can be improved. A separate report documents similar flow quality surveys conducted in the diffuser section of the Icing Research Tunnel. The flow quality studies were conducted at several locations around the tunnel loop. Pressure, velocity, and flow angularity measurements were made by using both fixed and translating probes. Although surveys were made throughout the tunnel loop, emphasis was placed on the test section and tunnel areas directly upstream of the test section (settling chamber, bellmouth, and cooler). Flow visualization, by video recording smoke and tuft patterns, was also used during these studies. A great deal of flow visualization work was conducted in the area of the drive fan. Information gathered there will be used to improve the flow quality upstream and downstream of the fan.

Propagating wave in active region-loops, located over the solar disk observed by the Interface Region Imaging Spectrograph

NASA Astrophysics Data System (ADS)

Zhang, B.; Hou, Y. J.; Zhang, J.

2018-03-01

Aims: We aim to ascertain the physical parameters of a propagating wave over the solar disk detected by the Interface Region Imaging Spectrograph (IRIS). Methods: Using imaging data from the IRIS and the Solar Dynamic Observatory (SDO), we tracked bright spots to determine the parameters of a propagating transverse wave in active region (AR) loops triggered by activation of a filament. Deriving the Doppler velocity of Si IV line from spectral observations of IRIS, we have determined the rotating directions of active region loops which are relevant to the wave. Results: On 2015 December 19, a filament was located on the polarity inversion line of the NOAA AR 12470. The filament was activated and then caused a C1.1 two-ribbon flare. Between the flare ribbons, two rotation motions of a set of bright loops were observed to appear in turn with opposite directions. Following the end of the second rotation, a propagating wave and an associated transverse oscillation were detected in these bright loops. In 1400 Å channel, there was bright material flowing along the loops in a wave-like manner, with a period of 128 s and a mean amplitude of 880 km. For the transverse oscillation, we tracked a given loop and determine the transverse positions of the tracking loop in a limited longitudinal range. In both of 1400 Å and 171 Å channels, approximately four periods are distinguished during the transverse oscillation. The mean period of the oscillation is estimated as 143 s and the displacement amplitude as between 1370 km and 690 km. We interpret these oscillations as a propagating kink wave and obtain its speed of 1400 km s-1. Conclusions: Our observations reveal that a flare associated with filament activation could trigger a kink propagating wave in active region loops over the solar disk. Movies associated to Figs. 1-4 are available at http://https://www.aanda.org

Improved vortex reactor system

DOEpatents

Diebold, J.P.; Scahill, J.W.

1995-05-09

An improved vortex reactor system is described for affecting fast pyrolysis of biomass and Refuse Derived Fuel (RDF) feed materials comprising: a vortex reactor having its axis vertically disposed in relation to a jet of a horizontally disposed steam ejector that impels feed materials from a feeder and solids from a recycle loop along with a motive gas into a top part of said reactor. 12 figs.

Unipolar memristive Switching in Bulk Negative Temperature Coefficient Thermosensitive Ceramics

PubMed Central

Wu, Hongya; Cai, Kunpeng; Zhou, Ji; Li, Bo; Li, Longtu

2013-01-01

A memristive phenomenon was observed in macroscopic bulk negative temperature coefficient nickel monoxide (NiO) ceramic material. Current-voltage characteristics of memristors, pinched hysteretic loops were systematically observed in the Ag/NiO/Ag cell. A thermistor-based model for materials with negative temperature coefficient was proposed to explain the mechanism of the experimental phenomena. Most importantly, the results demonstrate the potential for a realization of memristive systems based on macroscopic bulk materials. PMID:24255717

Highly Efficient Oxygen-Storage Material with Intrinsic Coke Resistance for Chemical Looping Combustion-Based CO2 Capture.

PubMed

Imtiaz, Qasim; Kurlov, Alexey; Rupp, Jennifer Lilia Marguerite; Müller, Christoph Rüdiger

2015-06-22

Chemical looping combustion (CLC) and chemical looping with oxygen uncoupling (CLOU) are emerging thermochemical CO2 capture cycles that allow the capture of CO2 with a small energy penalty. Here, the development of suitable oxygen carrier materials is a key aspect to transfer these promising concepts to practical installations. CuO is an attractive material for CLC and CLOU because of its high oxygen-storage capacity (20 wt %), fast reaction kinetics, and high equilibrium partial pressure of oxygen at typical operating temperatures (850-1000 °C). However, despite its promising characteristics, its low Tammann temperature requires the development of new strategies to phase-stabilize CuO-based oxygen carriers. In this work, we report a strategy based on stabilization by co-precipitated ceria (CeO2-x ), which allowed us to increase the oxygen capacity, coke resistance, and redox stability of CuO-based oxygen carriers substantially. The performance of the new oxygen carriers was evaluated in detail and compared to the current state-of-the-art materials, that is, Al2 O3 -stabilized CuO with similar CuO loadings. We also demonstrate that the higher intrinsic oxygen uptake, release, and mobility in CeO2-x -stabilized CuO leads to a three times higher carbon deposition resistance compared to that of Al2 O3 -stabilized CuO. Moreover, we report a high cyclic stability without phase intermixing for CeO2-x -supported CuO. This was accompanied by a lower reduction temperature compared to state-of-the-art Al2 O3 -supported CuO. As a result of its high resistance towards carbon deposition and fast oxygen uncoupling kinetics, CeO2-x -stabilized CuO is identified as a very promising material for CLC- and CLOU-based CO2 capture architectures. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

40 CFR 146.68 - Testing and monitoring requirements.

Code of Federal Regulations, 2012 CFR

2012-07-01

... stream; or (ii) Routing the waste stream through a loop constructed with the material used in the well... mechanical integrity testing as follows: (1) The long string casing, injection tube, and annular seal shall...

40 CFR 146.68 - Testing and monitoring requirements.

Code of Federal Regulations, 2013 CFR

2013-07-01

... stream; or (ii) Routing the waste stream through a loop constructed with the material used in the well... mechanical integrity testing as follows: (1) The long string casing, injection tube, and annular seal shall...

40 CFR 146.68 - Testing and monitoring requirements.

Code of Federal Regulations, 2014 CFR

2014-07-01

... stream; or (ii) Routing the waste stream through a loop constructed with the material used in the well... mechanical integrity testing as follows: (1) The long string casing, injection tube, and annular seal shall...

Ni-rich precipitates in a lead bismuth eutectic loop

NASA Astrophysics Data System (ADS)

Kikuchi, K.; Saito, S.; Hamaguchi, D.; Tezuka, M.

2010-03-01

Solidified LBE was sampled from the specimens, electro-magnetic pump, filter, drain valve and oxygen sensor at the JAEA Lead Bismuth Loop-1 (JLBL-1) where the structural material was made of SS316. The concentration of Ni, Fe and Cr in LBE were analyzed by the Inductive Coupled Plasma atomic emission spectrometer. It was concluded that the solution of Ni into LBE was not saturated although the concentration of Fe and Cr almost achieved to the values in the literature. A needle-type structure appeared on the surface of solidified LBE inside the tube specimens. It was found to be Ni-rich precipitates by X-ray analyses (Field Emission Scanning Electron Microscope, FE-SEM). LBE samples collected from a circulating loop after discharging did not show the amount of impurities equivalent to the LBE bulk property.

Fiber gasket and method of making same

DOEpatents

Bruck, Gerald Joseph; Alvin, Mary Anne; Smeltzer, Eugene E.

2003-01-01

A gasket (1) is made by repetitively spirally winding a fiber (3) back on itself in a closed path. The gasket (1) so made has a multi-layer spiral winding (1) formed in a loop (5). The fiber (3) can be wound at a constant wrap rate to form a gasket with a uniform cross-section around the loop. Alternatively, the wrap rate can be varied, increased to increase cross-sectional bulk, and decreased to reduce cross-section bulk around the loop (5). Also, the spiral winding (7) can be applied over a core (13) of either strands of the fiber (3) or a dissimilar material providing a desired property such as resiliency, stiffness or others. For high temperature applications, a ceramic fiber (3) can be used. The gasket (1) can have any of various geometric configurations with or without a core (13).

Flares observed by the normal incidence X-ray telescope on 1989 September 11

NASA Technical Reports Server (NTRS)

Herant, M.; Pardo, F.; Spiller, E.; Golub, L.

1991-01-01

Two solar flare events have been observed in soft X-rays during a sounding-rocket flight of the Normal-Incidence X-ray Telescope payload on September 11, 1989. The flare in X-rays involves a single bright loop crossing the neutral line, and having its footpoints at the southern ends of the ribbons; this loop accounts for more than 66 percent of the emission. Within the remainder of each of the flare ribbons, a complex coronal structure is also observed to be interacting with the main flare loop. A second event, in an active region at the limb, has a strong correlation with H-alpha images obtained at the same time. This indicates the coexistence, and indeed the close proximity, of coronal and chromospheric temperature material. Interpretations of this phenomenon are discussed.

The Effects of Closed-Loop Medical Devices on the Autonomy and Accountability of Persons and Systems.

PubMed

Kellmeyer, Philipp; Cochrane, Thomas; Müller, Oliver; Mitchell, Christine; Ball, Tonio; Fins, Joseph J; Biller-Andorno, Nikola

2016-10-01

Closed-loop medical devices such as brain-computer interfaces are an emerging and rapidly advancing neurotechnology. The target patients for brain-computer interfaces (BCIs) are often severely paralyzed, and thus particularly vulnerable in terms of personal autonomy, decisionmaking capacity, and agency. Here we analyze the effects of closed-loop medical devices on the autonomy and accountability of both persons (as patients or research participants) and neurotechnological closed-loop medical systems. We show that although BCIs can strengthen patient autonomy by preserving or restoring communicative abilities and/or motor control, closed-loop devices may also create challenges for moral and legal accountability. We advocate the development of a comprehensive ethical and legal framework to address the challenges of emerging closed-loop neurotechnologies like BCIs and stress the centrality of informed consent and refusal as a means to foster accountability. We propose the creation of an international neuroethics task force with members from medical neuroscience, neuroengineering, computer science, medical law, and medical ethics, as well as representatives of patient advocacy groups and the public.

A loop-based neural architecture for structured behavior encoding and decoding.

PubMed

Gisiger, Thomas; Boukadoum, Mounir

2018-02-01

We present a new type of artificial neural network that generalizes on anatomical and dynamical aspects of the mammal brain. Its main novelty lies in its topological structure which is built as an array of interacting elementary motifs shaped like loops. These loops come in various types and can implement functions such as gating, inhibitory or executive control, or encoding of task elements to name a few. Each loop features two sets of neurons and a control region, linked together by non-recurrent projections. The two neural sets do the bulk of the loop's computations while the control unit specifies the timing and the conditions under which the computations implemented by the loop are to be performed. By functionally linking many such loops together, a neural network is obtained that may perform complex cognitive computations. To demonstrate the potential offered by such a system, we present two neural network simulations. The first illustrates the structure and dynamics of a single loop implementing a simple gating mechanism. The second simulation shows how connecting four loops in series can produce neural activity patterns that are sufficient to pass a simplified delayed-response task. We also show that this network reproduces electrophysiological measurements gathered in various regions of the brain of monkeys performing similar tasks. We also demonstrate connections between this type of neural network and recurrent or long short-term memory network models, and suggest ways to generalize them for future artificial intelligence research. Copyright © 2017 Elsevier Ltd. All rights reserved.

Validation of Hardware in the Loop (HIL) Simulation for Use in Heavy Truck Stability Control System Effectiveness Research

DOT National Transportation Integrated Search

2009-04-27

A Hardware in the Loop (HiL) system was developed to investigate heavy truck instability due to loss of control and rollover situations with and without ESC/RSC systems for a wide range of maneuvers and speeds. The purpose of this HiL model is to exa...

Electrical Engineering and Nontechnical Design Variables of Multiple Inductive Loop Systems for Auditoriums

ERIC Educational Resources Information Center

Alterovitz, Gil

2004-01-01

This research analyzed both engineering and nontechnical issues involved in the use of Induction Loop Amplification (ILA) devices in auditoriums or large gathering places for hard-of-hearing individuals. A variety of parameters need to be taken into account to determine an optimal shape/configuration for the ILA device. In many cases, an optimal…

Improved process robustness by using closed loop control in deep drawing applications

NASA Astrophysics Data System (ADS)

Barthau, M.; Liewald, M.; Christian, Held

2017-09-01

The production of irregular shaped deep-drawing parts with high quality requirements, which are common in today’s automotive production, permanently challenges production processes. High requirements on lightweight construction of passenger car bodies following European regulations until 2020 have been massively increasing the use of high strength steels substantially for years and are also leading to bigger challenges in sheet metal part production. Of course, the more and more complex shapes of today’s car body shells also intensify the issue due to modern and future design criteria. The metal forming technology tries to meet these challenges by developing a highly sophisticated layout of deep drawing dies that consider part quality requirements, process robustness and controlled material flow during the deep or stretch drawing process phase. A new method for controlling material flow using a closed loop system was developed at the IFU Stuttgart. In contrast to previous approaches, this new method allows a control intervention during the deep-drawing stroke. The blank holder force around the outline of the drawn part is used as control variable. The closed loop is designed as trajectory follow up with feed forward control. The used command variable is the part-wall stress that is measured with a piezo-electric measuring pin. In this paper the used control loop will be described in detail. The experimental tool that was built for testing the new control approach is explained here with its features. A method for gaining the follow up trajectories from simulation will also be presented. Furthermore, experimental results considering the robustness of the deep drawing process and the gain in process performance with developed control loop will be shown. Finally, a new procedure for the industrial application of the new control method of deep drawing will be presented by using a new kind of active element to influence the local blank holder pressure onto part flange.

Study of mitochondria D-loop gene to detect the heterogeneity of gemak in Turnicidae family

NASA Astrophysics Data System (ADS)

Setiati, N.; Partaya

2018-03-01

As a part of life biodiversity, birds in Turnicidae family should be preserved from the extinction and its type heterogeneity decline. One effort for giving the strategic base of plasma nutfah conservation is through genetic heterogeneity study. The aim of the research is to analyze D-loop gen from DNA mitochondria of gemak bird in Turnicidae family molecularly. From the result of the analysis, it may be known the genetic heterogeneity of gemak bird based on the sequence of D-loop gen. The collection of both types of gemak of Turnicidae family is still easy since we can find them in ricefield area after harvest particularly for Gemakloreng (Turnix sylvatica), it means while gemak tegalan (Turnixsusciator) is getting difficult to find. Based on the above DNA quantification standard, the blood sample of Gemak in this research is mostly grouped into pure blood (ranges from 1,63 – 1,90), and it deserves to be used for PCR analysis. The sequencing analysis has not detected the sequence of nucleotide completely. However, it indicates sequence polymorphism of base as the arranger of D-loop gen. D-loop gen may identify genetic heterogeneity of gemak bird of Turnicidae family, but it is necessary to perform further sequencing analysis with PCR-RFLP technique. This complete nucleotide sequence is obtained and easy to detect after being cut restriction enzyme.

A Pilot Model for the NASA Simplified Aid for EVA Rescue (SAFER) (Single-Axis Pitch Task)

NASA Astrophysics Data System (ADS)

Handley, Patrick Mark

This thesis defines, tests, and validates a descriptive pilot model for a single-axis pitch control task of the Simplified Aid for EVA Rescue (SAFER). SAFER is a small propulsive jetpack used by astronauts for self-rescue. Pilot model research supports development of improved self-rescue strategies and technologies through insights into pilot behavior.This thesis defines a multi-loop pilot model. The innermost loop controls the hand controller, the middle loop controls pitch rate, and the outer loop controls pitch angle. A human-in-the-loop simulation was conducted to gather data from a human pilot. Quantitative and qualitative metrics both indicate that the model is an acceptable fit to the human data. Fuel consumption was nearly identical; time to task completion matched very well. There is some evidence that the model responds faster to initial pitch rates than the human, artificially decreasing the model's time to task completion. This pilot model is descriptive, not predictive, of the human pilot. Insights are made into pilot behavior from this research. Symmetry implies that the human responds to positive and negative initial conditions with the same strategy. The human pilot appears indifferent to pitch angles within 0.5 deg, coasts at a constant pitch rate 1.09 deg/s, and has a reaction delay of 0.1 s.

Long-Duration Testing of a Temperature-Swing Adsorption Compressor for Carbon Dioxide for Closed-Loop Air Revitalization Systems

NASA Technical Reports Server (NTRS)

Rosen, Micha; Mulloth, Lila; Varghese, Mini

2005-01-01

This paper describes the results of long-duration testing of a temperature-swing adsorption compressor that has application in the International Space Station (ISS) and future spacecraft for closing the air revitalization loop. The air revitalization system of the ISS operates in an open loop mode and relies on the resupply of oxygen and other consumables from Earth for the life support of astronauts. A compressor is required for delivering the carbon dioxide from a removal assembly to a reduction unit to recover oxygen and thereby closing the air-loop. The TSAC is a solid-state compressor that has the capability to remove CO2 from a low-pressure source, and subsequently store, compress, and deliver at a higher pressure as required by a processor. The TSAC is an ideal interface device for CO2 removal and reduction units in the air revitalization loop of a spacecraft for oxygen recovery. The TSAC was developed and its operation was successfully verified in integration tests with the flight-like Carbon Dioxide Removal Assembly (CDRA) at Marshall Space Flight Center prior to the long-duration tests. Long-duration tests reveal the impacts of repeated thermal cycling on the compressor components and the adsorbent material.

Is ambulatory monitoring for "community-acquired" syncope economically attractive? A cost-effectiveness analysis of a randomized trial of external loop recorders versus Holter monitoring.

PubMed

Rockx, Marie Antoinette; Hoch, Jeffrey S; Klein, George J; Yee, Raymond; Skanes, Allan C; Gula, Lorne J; Krahn, Andrew D

2005-11-01

Out patient ambulatory monitoring is often performed in patients with syncope that present in the primary care setting to include or exclude an arrhythmia. The cost-effectiveness of 2 monitoring strategies was assessed in a prospective randomized trial. One hundred patients referred for ambulatory monitoring with syncope or presyncope were randomized to a 1-month external loop recorder (n = 49) or 48-hour Holter monitor (n = 51). Patients were offered crossover if there was failed activation or no symptom recurrence. The primary end point was symptom-rhythm correlation during monitoring. Direct costs were calculated based on the 2003 Ontario Health Insurance Plan fee schedule, combined with calculation of labor, materials, service, and overhead for diagnostic testing and related equipment. Before enrollment, the cost of all previous health care resource use was USD 472 +/- USD 397 (range USD 21-USD 1965). In the loop recorder group, 63% of patients had symptom recurrence and successful activation, compared with 24% in the Holter group (P < .0001). The cost per Holter was USD 177.64, and per loop recorder, USD 533.56, with a similar cost per diagnosis with the 2 techniques. The incremental cost-effectiveness ratio of the loop recorder was USD 901.74 per extra successful diagnosis. A strategy of Holter followed by offered loop recorder trended toward lower cost than initial loop recorder followed by Holter (USD 481 +/- USD 267 vs USD 551 +/- USD 83, P = .08), but was associated with a lower overall diagnostic yield (49% vs 63%) and a resultant higher cost per diagnosis (USD 982 vs USD 871, P = .08). Bootstrapping suggested that 90% of incremental cost-effectiveness ratios were less than USD 1250. Despite the increased upfront cost of external loop recorders, the marked improvement in diagnostic yield offsets the cost. External loop recorders are an economically attractive alternative. First-line use of external loop recorders in patients with "community-acquired" syncope and presyncope should be considered to optimize diagnostic yield given its value.

Effect of exchange coupling on magnetic property in Sm-Co/α-Fe layered system

NASA Astrophysics Data System (ADS)

C, X. Sang; G, P. Zhao; W, X. Xia; X, L. Wan; F, J. Morvan; X, C. Zhang; L, H. Xie; J, Zhang; J, Du; A, R. Yan; P, Liu

2016-03-01

The hysteresis loops as well as the spin distributions of Sm-Co/α-Fe bilayers have been investigated by both three-dimensional (3D) and one-dimensional (1D) micromagnetic calculations, focusing on the effect of the interface exchange coupling under various soft layer thicknesses ts. The exchange coupling coefficient Ahs between the hard and soft layers varies from 1.8 × 10-6 erg/cm to 0.45 × 10-6 erg/cm, while the soft layer thickness increases from 2 nm to 10 nm. As the exchange coupling decreases, the squareness of the loop gradually deteriorates, both pinning and coercive fields rise up monotonically, and the nucleation field goes down. On the other hand, an increment of the soft layer thickness leads to a significant drop of the nucleation field, the deterioration of the hysteresis loop squareness, and an increase of the remanence. The simulated loops based on the 3D and 1D methods are consistent with each other and in good agreement with the measured loops for Sm-Co/α-Fe multilayers. Project supported by the National Natural Science Foundation of China (Grant Nos. 11074179 and 10747007), the National Basic Research Program of China (Grant No. 2014CB643702), the Zhejiang Provincial Natural Science Foundation of China (Grant No. LY14E010006), the Construction Plan for Scientific Research Innovation Teams of Universities in Sichuan Province, China (Grant No. 12TD008), the Scientific Research Foundation for the Returned Overseas Chinese Scholars of the Education Ministry, China, and the Program for Key Science and Technology Innovation Team of Zhejiang Province, China (Grant No. 2013TD08).

Improving accuracy of unbound resilient modulus testing

DOT National Transportation Integrated Search

1997-07-01

The P46 Laboratory Startup and Quality Control Procedure was developed to ensure the accuracy and reliability of the resilient modulus data produced while testing soil and aggregate materials using closed-loop servo-hydraulic systems. It was develope...

Slow Magnetosonic Waves and Fast Flows in Active Region Loops

NASA Technical Reports Server (NTRS)

Ofman, L.; Wang, T. J.; Davila, J. M.

2012-01-01

Recent extreme ultraviolet spectroscopic observations indicate that slow magnetosonic waves are present in active region (AR) loops. Some of the spectral data were also interpreted as evidence of fast (approx 100-300 km/s) quasiperiodic flows. We have performed three-dimensional magnetohydrodynamic (3D MHD) modeling of a bipolar AR that contains impulsively generated waves and flows in coronal loops. The model AR is initiated with a dipole magnetic field and gravitationally stratified density, with an upflow-driven steadily or periodically in localized regions at the footpoints of magnetic loops. The resulting flows along the magnetic field lines of the AR produce higher density loops compared to the surrounding plasma by injection of material into the flux tubes and the establishment of siphon flow.We find that the impulsive onset of flows with subsonic speeds result in the excitation of damped slow magnetosonic waves that propagate along the loops and coupled nonlinearly driven fast-mode waves. The phase speed of the slow magnetosonic waves is close to the coronal sound speed. When the amplitude of the driving pulses is increased we find that slow shock-like wave trains are produced. When the upflows are driven periodically, undamped oscillations are produced with periods determined by the periodicity of the upflows. Based on the results of the 3D MHD model we suggest that the observed slow magnetosonic waves and persistent upflows may be produced by the same impulsive events at the bases of ARs.

DETECTION OF SUPERSONIC DOWNFLOWS AND ASSOCIATED HEATING EVENTS IN THE TRANSITION REGION ABOVE SUNSPOTS

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

Kleint, L.; Martínez-Sykora, J.; Antolin, P.

Interface Region Imaging Spectrograph data allow us to study the solar transition region (TR) with an unprecedented spatial resolution of 0.''33. On 2013 August 30, we observed bursts of high Doppler shifts suggesting strong supersonic downflows of up to 200 km s{sup –1} and weaker, slightly slower upflows in the spectral lines Mg II h and k, C II 1336, Si IV 1394 Å, and 1403 Å, that are correlated with brightenings in the slitjaw images (SJIs). The bursty behavior lasts throughout the 2 hr observation, with average burst durations of about 20 s. The locations of these short-lived events appear to bemore » the umbral and penumbral footpoints of EUV loops. Fast apparent downflows are observed along these loops in the SJIs and in the Atmospheric Imaging Assembly, suggesting that the loops are thermally unstable. We interpret the observations as cool material falling from coronal heights, and especially coronal rain produced along the thermally unstable loops, which leads to an increase of intensity at the loop footpoints, probably indicating an increase of density and temperature in the TR. The rain speeds are on the higher end of previously reported speeds for this phenomenon, and possibly higher than the free-fall velocity along the loops. On other observing days, similar bright dots are sometimes aligned into ribbons, resembling small flare ribbons. These observations provide a first insight into small-scale heating events in sunspots in the TR.« less

Human life support during interplanetary travel and domicile. II - Generic Modular Flow Schematic modeling

NASA Technical Reports Server (NTRS)

Farral, Joseph F.; Seshan, P. K.; Rohatgi, Naresh K.

1991-01-01

This paper describes the Generic Modular Flow Schematic (GMFS) architecture capable of encompassing all functional elements of a physical/chemical life support system (LSS). The GMFS can be implemented to synthesize, model, analyze, and quantitatively compare many configurations of LSSs, from a simple, completely open-loop to a very complex closed-loop. The GMFS model is coded in ASPEN, a state-of-the-art chemical process simulation program, to accurately compute the material, heat, and power flow quantities for every stream in each of the subsystem functional elements (SFEs) in the chosen configuration of a life support system. The GMFS approach integrates the various SFEs and subsystems in a hierarchical and modular fashion facilitating rapid substitutions and reconfiguration of a life support system. The comprehensive ASPEN material and energy balance output is transferred to a systems and technology assessment spreadsheet for rigorous system analysis and trade studies.

Plateau on temperature dependence of magnetization of nanostructured rare earth titanates

NASA Astrophysics Data System (ADS)

Rinkevich, A. B.; Korolev, A. V.; Samoylovich, M. I.; Demokritov, S. O.; Perov, D. V.

2018-05-01

Magnetic properties of nanocomposite materials containing particles of rare earth titanates of R2Ti2O7 type, where R is a rare earth ion, including "spin ice" materials are investigated. The descending branches of hysteresis loop have been studied in detail in temperature range from 2 to 50 K. It has been shown that nanocomposites with Yb2Ti2O7, Dy2Ti2O7 and Er2Ti2O7 particles have one intersection point of the descending branches in some temperature range unlike many other nanocomposites. It is shown that magnetization has only weak temperature dependence near this point. It has been obtained that nanocomposites with Pr2Ti2O7 and Nd2Ti2O7 particles have no hysteresis loop. All above findings point out to unusual magnetic structures of the studied samples.

Recent upgrades and new scientific infrastructure of MARIA research reactor, Otwock-Swierk, Poland

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

NONE

The MARIA reactor is open-pool type, water and beryllium moderated. It has two independent primary cooling systems: fuel and pool cooling system. Each fuel assembly is cooled down separately in pressurized channels with individual performances characterization. The fuel assemblies consist of five layers of bent plates or six concentric tubes. Currently it is one of the most powerful research reactors in Europe with operation availability at least up to 2030. Its nominal thermal power is 30 MW. It is characterized by high neutron flux density: up to 3x10{sup 14} n cm{sup -2} s{sup -1} in case of thermal neutrons, andmore » up to 2x10{sup 13} n cm{sup -2} s{sup -1} in case of fast neutrons. The reactor is operated for ca. 4000 h per year. The reactor facility is equipped with fully equipped three hot cells with shielding up to 10{sup 15} Bq. Adjacent to the reactor facility, the radio-pharmaceutics plant (POLATOM) and Material Research Laboratory are located. They are equipped with a number of hot cells with instrumentation. The transport system of radioactive materials from reactor facility to Material Research Laboratory is available. During 2014 the MARIA reactor has been operated with three different types of fuel the same time: previous 36% enriched fuel, and two types of new LEU fuels. In the meantime, molybdenum irradiation programme has been developed. Maria is a multifunctional research tool, with a notable application in production of radioisotopes, radio-pharmaceutics manufacturing (ca. 600 TBq/y), {sup 99}Mo for medical scintigraphy (ca. 6000 TBq/y), neutron transmutation doping of silicon single crystals, wide scientific research based on neutron beams utilization. From the beginning MARIA reactor was intended for loop and fuel testing research activities. Currently it is used mostly as material testing and irradiation facility and for that reason it has wide experimental capabilities. There are eight horizontal irradiation channels from among whom six of them are equipped with instrumentation for condensed matter physics research: - H3 - spectrometer and diffractometer with double monochromator; - H4 - small angle scattering spectrometer; - H5 - polarized neutrons spectrometer; - H6, H7 - two 3-axial crystal neutron spectrometers; - H8 - neutron radiography stand. For two horizontal channels are ongoing exploitation programs: - H2 - station with epithermal neutron beam produced in uranium converter is being developed. Intelligent converter will be installed on the periphery of reactor core. The intensity of the beam will be at the level 2x10{sup 9} n cm{sup -2}s{sup -1} what makes the beam unique in the Europe. - H1 - special pneumatic horizontal mail is being developed for irradiation material samples in the vicinity of the core i.e. in the distal part of the H1 channel. The number of neutron irradiation facilities in MARIA reactor is increasing every year. Numerous of thermal neutron irradiation channels including fast hydraulic rabbit system and large size channels for fast neutron irradiation are used routinely. Recently new in-pile facility with ITER-like neutron energy spectrum for 14 MeV neutron irradiation has been constructed. Taking into account its performance and ability of almost incessant operation the facility appears as one of the most powerful 14 MeV neutron sources. The facility shall be used for material research connected with thermonuclear devices (ITER) and 4. generation nuclear reactors. The system of independent fuels channels used in MARIA reactor appear to be very flexible and very convenient to be used as irradiation channels for uranium targets for {sup 99}Mo production. Currently, MARIA reactor supplies ca. 18% world production of {sup 99}Mo. The MARIA reactor research activities are still extended. The current scientific projects are connected e.g. with silicon neutron transmutation doping, in-pile gamma heating measurements, French calculation codes implementation (TRIPOLI4, APOLLO2). The horizontal neutron beams utilization is also developed. The MARIA reactor, due to its primary application connected with loop and fuel testing, is very convenient for testing the nuclear instrumentation, control and measurement systems.« less

The Life Cycle Evaluation Model of External Diseconomy of Open-loop Supply Chain

NASA Astrophysics Data System (ADS)

Liu, Qian; Hu, Tianjun

2017-08-01

In recent years, with the continuous deterioration of pollution, resource space is gradually narrowed, the number of waste items increased, people began to use the method of recycling on waste products to ease the pressure on the environment. This paper adopted the external diseconomy of open-loop supply chain as the research object and constructed the model by the life cycle evaluation method, comparative analysis through the case. This paper also concludes that the key to solving the problem is to realize the closed-loop supply chain and building reverse logistics system is of great significance.

Effect of GNSS receiver carrier phase tracking loops on earthquake monitoring performance

NASA Astrophysics Data System (ADS)

Clare, Adam; Lin, Tao; Lachapelle, Gérard

2017-06-01

This research focuses on the performance of GNSS receiver carrier phase tracking loops for early earthquake monitoring systems. An earthquake was simulated using a hardware simulator and position, velocity and acceleration displacements were obtained to recreate the dynamics of the 2011 Tohoku earthquake. Using a software defined receiver, GSNRx, tracking bandwidths of 5, 10, 15, 20, 30, 40 and 50 Hz along with integration times of 1, 5 and 10 ms were tested. Using the phase lock indicator, an adaptive tracking loop was designed and tested to maximize performance for this application.

Closed Brayton cycle power conversion systems for nuclear reactors :

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

Wright, Steven A.; Lipinski, Ronald J.; Vernon, Milton E.

2006-04-01

This report describes the results of a Sandia National Laboratories internally funded research program to study the coupling of nuclear reactors to gas dynamic Brayton power conversion systems. The research focused on developing integrated dynamic system models, fabricating a 10-30 kWe closed loop Brayton cycle, and validating these models by operating the Brayton test-loop. The work tasks were performed in three major areas. First, the system equations and dynamic models for reactors and Closed Brayton Cycle (CBC) systems were developed and implemented in SIMULINKTM. Within this effort, both steady state and dynamic system models for all the components (turbines, compressors,more » reactors, ducting, alternators, heat exchangers, and space based radiators) were developed and assembled into complete systems for gas cooled reactors, liquid metal reactors, and electrically heated simulators. Various control modules that use proportional-integral-differential (PID) feedback loops for the reactor and the power-conversion shaft speed were also developed and implemented. The simulation code is called RPCSIM (Reactor Power and Control Simulator). In the second task an open cycle commercially available Capstone C30 micro-turbine power generator was modified to provide a small inexpensive closed Brayton cycle test loop called the Sandia Brayton test-Loop (SBL-30). The Capstone gas-turbine unit housing was modified to permit the attachment of an electrical heater and a water cooled chiller to form a closed loop. The Capstone turbine, compressor, and alternator were used without modification. The Capstone systems nominal operating point is 1150 K turbine inlet temperature at 96,000 rpm. The annular recuperator and portions of the Capstone control system (inverter) and starter system also were reused. The rotational speed of the turbo-machinery is controlled by adjusting the alternator load by using the electrical grid as the load bank. The SBL-30 test loop was operated at the manufacturers site (Barber-Nichols Inc.) and installed and operated at Sandia. A sufficiently detailed description of the loop is provided in this report along with the design characteristics of the turbo-alternator-compressor set to allow other researchers to compare their results with those measured in the Sandia test-loop. The third task consisted of a validation effort. In this task the test loop was operated and compared with the modeled results to develop a more complete understanding of this electrically heated closed power generation system and to validate the model. The measured and predicted system temperatures and pressures are in good agreement, indicating that the model is a reasonable representation of the test loop. Typical deviations between the model and the hardware results are less than 10%. Additional tests were performed to assess the capability of the Brayton engine to continue to remove decay heat after the reactor/heater is shutdown, to develop safe and effective control strategies, and to access the effectiveness of gas inventory control as an alternative means to provide load following. In one test the heater power was turned off to simulate a rapid reactor shutdown, and the turbomachinery was driven solely by the sensible heat stored in the heater for over 71 minutes without external power input. This is an important safety feature for CBC systems as it means that the closed Brayton loop will keep cooling the reactor without the need for auxiliary power (other than that needed to circulate the waste heat rejection coolant) provided the heat sink is available.« less

A SOLAR TORNADO OBSERVED BY AIA/SDO: ROTATIONAL FLOW AND EVOLUTION OF MAGNETIC HELICITY IN A PROMINENCE AND CAVITY

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

Li, Xing; Morgan, Huw; Leonard, Drew

During 2011 September 24, as observed by the Atmospheric Imaging Assembly instrument of the Solar Dynamic Observatory and ground-based H{alpha} telescopes, a prominence and associated cavity appeared above the southwest limb. On 2011 September 25 8:00 UT, material flows upward from the prominence core along a narrow loop-like structure, accompanied by a rise ({>=}50,000 km) of the prominence core and the loop. As the loop fades by 10:00, small blobs and streaks of varying brightness rotate around the top part of the prominence and cavity, mimicking a cyclone. The most intense and coherent rotation lasts for over three hours, withmore » emission in both hot ({approx}1 MK) and cold (hydrogen and helium) lines. We suggest that the cyclonic appearance and overall evolution of the structure can be interpreted in terms of the expansion of helical structures into the cavity, and the movement of plasma along helical structures which appears as a rotation when viewed along the helix axis. The coordinated movement of material between prominence and cavity suggests that they are structurally linked. Complexity is great due to the combined effect of these actions and the line-of-sight integration through the structure which contains tangled fields.« less

Prostate Specific Expression of Maspin in a Transgenic Mouse Model: Implications in Prostate Carcinogenesis

DTIC Science & Technology

2004-05-01

should not be construed as an official Department of the Army position, policy or decision unless so designated by other documentation. 20050603 257 r...such material. Where material from documents designated for limited distribution is quoted, permission has been obtained to use the material...amino acid peptide located in the reactive site loop of maspin, a region designated as AbS4A. The antibody was purified using an AbS4A sulfo-linked

A High-Order, Linear Time-Invariant Model for Application to Higher Harmonic Control and Flight Control System Interaction

NASA Technical Reports Server (NTRS)

Cheng, Rendy P.; Tischler, Mark B.; Celi, Roberto

2006-01-01

This research describes a new methodology for the extraction of a high-order, linear time invariant model, which allows the periodicity of the helicopter response to be accurately captured. This model provides the needed level of dynamic fidelity to permit an analysis and optimization of the AFCS and HHC algorithms. The key results of this study indicate that the closed-loop HHC system has little influence on the AFCS or on the vehicle handling qualities, which indicates that the AFCS does not need modification to work with the HHC system. However, the results show that the vibration response to maneuvers must be considered during the HHC design process, and this leads to much higher required HHC loop crossover frequencies. This research also demonstrates that the transient vibration responses during maneuvers can be reduced by optimizing the closed-loop higher harmonic control algorithm using conventional control system analyses.

Thermal Technology Development Activities at the Goddard Space Flight Center - 2001

NASA Technical Reports Server (NTRS)

Butler, Dan

2002-01-01

This presentation provides an overview of thermal technology development activities carried out at NASA's Goddard Space Flight Center during 2001. Specific topics covered include: two-phase systems (heat pipes, capillary pumped loops, vapor compression systems and phase change materials), variable emittance systems, advanced coatings, high conductivity materials and electrohydrodynamic (EHD) thermal coatings. The application of these activities to specific space missions is also discussed.

A LabVIEW model incorporating an open-loop arterial impedance and a closed-loop circulatory system.

PubMed

Cole, R T; Lucas, C L; Cascio, W E; Johnson, T A

2005-11-01

While numerous computer models exist for the circulatory system, many are limited in scope, contain unwanted features or incorporate complex components specific to unique experimental situations. Our purpose was to develop a basic, yet multifaceted, computer model of the left heart and systemic circulation in LabVIEW having universal appeal without sacrificing crucial physiologic features. The program we developed employs Windkessel-type impedance models in several open-loop configurations and a closed-loop model coupling a lumped impedance and ventricular pressure source. The open-loop impedance models demonstrate afterload effects on arbitrary aortic pressure/flow inputs. The closed-loop model catalogs the major circulatory waveforms with changes in afterload, preload, and left heart properties. Our model provides an avenue for expanding the use of the ventricular equations through closed-loop coupling that includes a basic coronary circuit. Tested values used for the afterload components and the effects of afterload parameter changes on various waveforms are consistent with published data. We conclude that this model offers the ability to alter several circulatory factors and digitally catalog the most salient features of the pressure/flow waveforms employing a user-friendly platform. These features make the model a useful instructional tool for students as well as a simple experimental tool for cardiovascular research.

An Environmental for Hardware-in-the-Loop Formation Navigation and Control

NASA Technical Reports Server (NTRS)

Burns, Rich; Naasz, Bo; Gaylor, Dave; Higinbotham, John

2004-01-01

Recent interest in formation flying satellite systems has spurred a considerable amount of research in the relative navigation and control of satellites. Development in this area has included new estimation and control algorithms as well as sensor and actuator development specifically geared toward the relative control problem. This paper describes a simulation facility, the Formation Flying Test Bed (FFTB) at NASA Goddard Space Flight Center, which allows engineers to test new algorithms for the formation flying problem with relevant GN&C hardware in a closed loop simulation. The FFTB currently supports the inclusion of GPS receiver hardware in the simulation loop. Support for satellite crosslink ranging technology is at a prototype stage. This closed-loop, hardware inclusive simulation capability permits testing of navigation and control software in the presence of the actual hardware with which the algorithms must interact. This capability provides the navigation or control developer with a perspective on how the algorithms perform as part of the closed-loop system. In this paper, the overall design and evolution of the FFTB are presented. Each component of the FFTB is then described. Interfaces between the components of the FFTB are shown and the interfaces to and between navigation and control software are described. Finally, an example of closed-loop formation control with GPS receivers in the loop is presented.

Conceptualization and validation of an open-source closed-loop deep brain stimulation system in rat.

PubMed

Wu, Hemmings; Ghekiere, Hartwin; Beeckmans, Dorien; Tambuyzer, Tim; van Kuyck, Kris; Aerts, Jean-Marie; Nuttin, Bart

2015-04-21

Conventional deep brain stimulation (DBS) applies constant electrical stimulation to specific brain regions to treat neurological disorders. Closed-loop DBS with real-time feedback is gaining attention in recent years, after proved more effective than conventional DBS in terms of pathological symptom control clinically. Here we demonstrate the conceptualization and validation of a closed-loop DBS system using open-source hardware. We used hippocampal theta oscillations as system input, and electrical stimulation in the mesencephalic reticular formation (mRt) as controller output. It is well documented that hippocampal theta oscillations are highly related to locomotion, while electrical stimulation in the mRt induces freezing. We used an Arduino open-source microcontroller between input and output sources. This allowed us to use hippocampal local field potentials (LFPs) to steer electrical stimulation in the mRt. Our results showed that closed-loop DBS significantly suppressed locomotion compared to no stimulation, and required on average only 56% of the stimulation used in open-loop DBS to reach similar effects. The main advantages of open-source hardware include wide selection and availability, high customizability, and affordability. Our open-source closed-loop DBS system is effective, and warrants further research using open-source hardware for closed-loop neuromodulation.

Conceptualization and validation of an open-source closed-loop deep brain stimulation system in rat

PubMed Central

Wu, Hemmings; Ghekiere, Hartwin; Beeckmans, Dorien; Tambuyzer, Tim; van Kuyck, Kris; Aerts, Jean-Marie; Nuttin, Bart

2015-01-01

Conventional deep brain stimulation (DBS) applies constant electrical stimulation to specific brain regions to treat neurological disorders. Closed-loop DBS with real-time feedback is gaining attention in recent years, after proved more effective than conventional DBS in terms of pathological symptom control clinically. Here we demonstrate the conceptualization and validation of a closed-loop DBS system using open-source hardware. We used hippocampal theta oscillations as system input, and electrical stimulation in the mesencephalic reticular formation (mRt) as controller output. It is well documented that hippocampal theta oscillations are highly related to locomotion, while electrical stimulation in the mRt induces freezing. We used an Arduino open-source microcontroller between input and output sources. This allowed us to use hippocampal local field potentials (LFPs) to steer electrical stimulation in the mRt. Our results showed that closed-loop DBS significantly suppressed locomotion compared to no stimulation, and required on average only 56% of the stimulation used in open-loop DBS to reach similar effects. The main advantages of open-source hardware include wide selection and availability, high customizability, and affordability. Our open-source closed-loop DBS system is effective, and warrants further research using open-source hardware for closed-loop neuromodulation. PMID:25897892

Non-linear control of a hydraulic piezo-valve using a generalised Prandtl-Ishlinskii hysteresis model

NASA Astrophysics Data System (ADS)

Stefanski, Frederik; Minorowicz, Bartosz; Persson, Johan; Plummer, Andrew; Bowen, Chris

2017-01-01

The potential to actuate proportional flow control valves using piezoelectric ceramics or other smart materials has been investigated for a number of years. Although performance advantages compared to electromagnetic actuation have been demonstrated, a major obstacle has proven to be ferroelectric hysteresis, which is typically 20% for a piezoelectric actuator. In this paper, a detailed study of valve control methods incorporating hysteresis compensation is made for the first time. Experimental results are obtained from a novel spool valve actuated by a multi-layer piezoelectric ring bender. A generalised Prandtl-Ishlinskii model, fitted to experimental training data from the prototype valve, is used to model hysteresis empirically. This form of model is analytically invertible and is used to compensate for hysteresis in the prototype valve both open loop, and in several configurations of closed loop real time control system. The closed loop control configurations use PID (Proportional Integral Derivative) control with either the inverse hysteresis model in the forward path or in a command feedforward path. Performance is compared to both open and closed loop control without hysteresis compensation via step and frequency response results. Results show a significant improvement in accuracy and dynamic performance using hysteresis compensation in open loop, but where valve position feedback is available for closed loop control the improvements are smaller, and so conventional PID control may well be sufficient. It is concluded that the ability to combine state-of-the-art multi-layer piezoelectric bending actuators with either sophisticated hysteresis compensation or closed loop control provides a route for the creation of a new generation of high performance piezoelectric valves.

A pilot modeling technique for handling-qualities research

NASA Technical Reports Server (NTRS)

Hess, R. A.

1980-01-01

A brief survey of the more dominant analysis techniques used in closed-loop handling-qualities research is presented. These techniques are shown to rely on so-called classical and modern analytical models of the human pilot which have their foundation in the analysis and design principles of feedback control. The optimal control model of the human pilot is discussed in some detail and a novel approach to the a priori selection of pertinent model parameters is discussed. Frequency domain and tracking performance data from 10 pilot-in-the-loop simulation experiments involving 3 different tasks are used to demonstrate the parameter selection technique. Finally, the utility of this modeling approach in handling-qualities research is discussed.

An analytical and experimental investigation of flutter suppression via piezoelectric actuation

NASA Technical Reports Server (NTRS)

Heeg, Jennifer

1992-01-01

The objective of this research was to analytically and experimentally study the capabilities of adaptive material plate actuators for suppressing flutter. Piezoelectrics are materials which are characterized by their ability to produce voltage when subjected to a mechanical strain. The converse piezoelectric effect can be utilized to actuate a structure by applying a voltage. For this investigation, a two degree of freedom wind-tunnel model was designed, analyzed, and tested. The model consisted of a rigid wing and a flexible mount system which permitted translational and rotational degrees of freedom. Actuators, made of piezoelectric material were affixed to leaf springs on the mount system. Command signals, applied to the piezoelectric actuators, exerted control over the closed-loop damping and stiffness properties. A mathematical aeroservoelastic model was constructed using finite element and stiffness properties. A mathematical aeroservoelastic model was constructed using finite element methods, laminated plate theory, and aeroelastic analysis tools. A flutter suppression control law was designed, implemented on a digital control computer, and tested to conditions 20 percent above the passive flutter speed of the model. The experimental results represent the first time that adaptive materials have been used to actively suppress flutter. It demonstrates that small, carefully-placed actuating plates can be used effectively to control aeroelastic response.

Crack stability in a representative piping system under combined inertial and seismic/dynamic displacement-controlled stresses. Subtask 1.3 final report

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

Scott, P.; Olson, R.; Wilkowski, O.G.

1997-06-01

This report presents the results from Subtask 1.3 of the International Piping Integrity Research Group (IPIRG) program. The objective of Subtask 1.3 is to develop data to assess analysis methodologies for characterizing the fracture behavior of circumferentially cracked pipe in a representative piping system under combined inertial and displacement-controlled stresses. A unique experimental facility was designed and constructed. The piping system evaluated is an expansion loop with over 30 meters of 16-inch diameter Schedule 100 pipe. The experimental facility is equipped with special hardware to ensure system boundary conditions could be appropriately modeled. The test matrix involved one uncracked andmore » five cracked dynamic pipe-system experiments. The uncracked experiment was conducted to evaluate piping system damping and natural frequency characteristics. The cracked-pipe experiments evaluated the fracture behavior, pipe system response, and stability characteristics of five different materials. All cracked-pipe experiments were conducted at PWR conditions. Material characterization efforts provided tensile and fracture toughness properties of the different pipe materials at various strain rates and temperatures. Results from all pipe-system experiments and material characterization efforts are presented. Results of fracture mechanics analyses, dynamic finite element stress analyses, and stability analyses are presented and compared with experimental results.« less

Tensile and Fatigue Testing and Material Hardening Model Development for 508 LAS Base Metal and 316 SS Similar Metal Weld under In-air and PWR Primary Loop Water Conditions

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

Mohanty, Subhasish; Soppet, William; Majumdar, Saurin

This report provides an update on an assessment of environmentally assisted fatigue for light water reactor components under extended service conditions. This report is a deliverable in September 2015 under the work package for environmentally assisted fatigue under DOE’s Light Water Reactor Sustainability program. In an April 2015 report we presented a baseline mechanistic finite element model of a two-loop pressurized water reactor (PWR) for systemlevel heat transfer analysis and subsequent thermal-mechanical stress analysis and fatigue life estimation under reactor thermal-mechanical cycles. In the present report, we provide tensile and fatigue test data for 508 low-alloy steel (LAS) base metal,more » 508 LAS heat-affected zone metal in 508 LAS–316 stainless steel (SS) dissimilar metal welds, and 316 SS-316 SS similar metal welds. The test was conducted under different conditions such as in air at room temperature, in air at 300 oC, and under PWR primary loop water conditions. Data are provided on materials properties related to time-independent tensile tests and time-dependent cyclic tests, such as elastic modulus, elastic and offset strain yield limit stress, and linear and nonlinear kinematic hardening model parameters. The overall objective of this report is to provide guidance to estimate tensile/fatigue hardening parameters from test data. Also, the material models and parameters reported here can directly be used in commercially available finite element codes for fatigue and ratcheting evaluation of reactor components under in-air and PWR water conditions.« less

Plant STAND P-loop NTPases: a current perspective of genome distribution, evolution, and function : Plant STAND P-loop NTPases: genomic organization, evolution, and molecular mechanism models contribute broadly to plant pathogen defense.

PubMed

Arya, Preeti; Acharya, Vishal

2018-02-01

STAND P-loop NTPase is the common weapon used by plant and other organisms from all three kingdoms of life to defend themselves against pathogen invasion. The purpose of this study is to review comprehensively the latest finding of plant STAND P-loop NTPase related to their genomic distribution, evolution, and their mechanism of action. Earlier, the plant STAND P-loop NTPase known to be comprised of only NBS-LRRs/AP-ATPase/NB-ARC ATPase. However, recent finding suggests that genome of early green plants comprised of two types of STAND P-loop NTPases: (1) mammalian NACHT NTPases and (2) NBS-LRRs. Moreover, YchF (unconventional G protein and members of P-loop NTPase) subfamily has been reported to be exceptionally involved in biotic stress (in case of Oryza sativa), thereby a novel member of STAND P-loop NTPase in green plants. The lineage-specific expansion and genome duplication events are responsible for abundance of plant STAND P-loop NTPases; where "moderate tandem and low segmental duplication" trajectory followed in majority of plant species with few exception (equal contribution of tandem and segmental duplication). Since the past decades, systematic research is being investigated into NBS-LRR function supported the direct recognition of pathogen or pathogen effectors by the latest models proposed via 'integrated decoy' or 'sensor domains' model. Here, we integrate the recently published findings together with the previous literature on the genomic distribution, evolution, and distinct models proposed for functional molecular mechanism of plant STAND P-loop NTPases.

Closed-loop and robust control of quantum systems.

PubMed

Chen, Chunlin; Wang, Lin-Cheng; Wang, Yuanlong

2013-01-01

For most practical quantum control systems, it is important and difficult to attain robustness and reliability due to unavoidable uncertainties in the system dynamics or models. Three kinds of typical approaches (e.g., closed-loop learning control, feedback control, and robust control) have been proved to be effective to solve these problems. This work presents a self-contained survey on the closed-loop and robust control of quantum systems, as well as a brief introduction to a selection of basic theories and methods in this research area, to provide interested readers with a general idea for further studies. In the area of closed-loop learning control of quantum systems, we survey and introduce such learning control methods as gradient-based methods, genetic algorithms (GA), and reinforcement learning (RL) methods from a unified point of view of exploring the quantum control landscapes. For the feedback control approach, the paper surveys three control strategies including Lyapunov control, measurement-based control, and coherent-feedback control. Then such topics in the field of quantum robust control as H(∞) control, sliding mode control, quantum risk-sensitive control, and quantum ensemble control are reviewed. The paper concludes with a perspective of future research directions that are likely to attract more attention.

Interactions among poverty, gender, and health systems affect women's participation in services to prevent HIV transmission from mother to child: A causal loop analysis.

PubMed

Yourkavitch, Jennifer; Hassmiller Lich, Kristen; Flax, Valerie L; Okello, Elialilia S; Kadzandira, John; Katahoire, Anne Ruhweza; Munthali, Alister C; Thomas, James C

2018-01-01

Retention in care remains an important issue for prevention of mother-to-child transmission (PMTCT) programs according to WHO guidelines, formerly called the "Option B+" approach. The objective of this study was to examine how poverty, gender, and health system factors interact to influence women's participation in PMTCT services. We used qualitative research, literature, and hypothesized variable connections to diagram causes and effects in causal loop models. We found that many factors, including antiretroviral therapy (ART) use, service design and quality, stigma, disclosure, spouse/partner influence, decision-making autonomy, and knowledge about PMTCT, influence psychosocial health, which in turn affects women's participation in PMTCT services. Thus, interventions to improve psychosocial health need to address many factors to be successful. We also found that the design of PMTCT services, a modifiable factor, is important because it affects several other factors. We identified 66 feedback loops that may contribute to policy resistance-that is, a policy's failure to have its intended effect. Our findings point to the need for a multipronged intervention to encourage women's continued participation in PMTCT services and for longitudinal research to quantify and test our causal loop model.

Comportement dynamique d'alliages a memoire de forme et application aux composites-AMF

NASA Astrophysics Data System (ADS)

de Santis, Silvio

Meeting current industrial, governmental and international standards regarding vibration and noise levels is a challenging task facing many engineers. These specifications are present in just about all fields of engineering, from aerospace to marine transportation, from automotive to railway transportation, from computer equipment to industrial working environments. An appropriate use of the remarkable properties of high damping metals (HIDAMETS) and shape memory alloy (SMA) reinforced composites emerges as a possible solution to these problems. Among many obstacles to overcome in developing such a technology, the implementation of reliable and adequate characterization techniques to determine dynamic properties of these materials appears to be of prime importance. The research efforts presented in this thesis are aimed at developing advanced techniques to characterize the dynamic behavior of HIDAMETS and SMA reinforced composites. These characterization results lead to the enhancement of numerical (finite element) and/or analytical methods for the simulation of dynamic responses of structures made of these materials. In particular, the research work has focused on three themes: the numerical and experimental validation of applying a characterization procedure developed for traditional composites to SMA reinforced composites; the development of a test bench for uniaxial hysteresis characterization of HIDAMETS in the medium frequency range; the hysteresis characterization and modeling of manganese copper (MnCu) and nickel titanium samples. The results obtained in the course of these efforts show that the characterization technique developed for traditional composites at the University of Brussels is sufficiently precise to successfully predict natural frequencies of complex SMA reinforced composite structures. Using the characterization to predict structural damping ratios, we observe a bias error in the prediction with respect to experimental results although the relative values between modes are consistent. Regarding the development of the test bench for uniaxial hysteresis characterization of HIDAMETS, results suggest that with the introduction of a few minor enhancements and with particular experimental precautions, the test bench can play an important role in characterizing HIDAMETS dynamic properties at various frequencies and strain amplitudes and in understanding micro mechanical mechanisms responsible for energy dissipation. Finally, uniaxial hysteresis loops and related parameters have been obtained with MnCu and NiTi samples. A material model based on dual kriging interpolation that expresses the tangent stiffness along these hysteresis loops as a function of strain and strain amplitude has also been developed.

Eglin virtual range database for hardware-in-the-loop testing

NASA Astrophysics Data System (ADS)

Talele, Sunjay E.; Pickard, J. W., Jr.; Owens, Monte A.; Foster, Joseph; Watson, John S.; Amick, Mary Amenda; Anthony, Kenneth

1998-07-01

Realistic backgrounds are necessary to support high fidelity hardware-in-the-loop testing. Advanced avionics and weapon system sensors are driving the requirement for higher resolution imagery. The model-test-model philosophy being promoted by the T&E community is resulting in the need for backgrounds that are realistic or virtual representations of actual test areas. Combined, these requirements led to a major upgrade of the terrain database used for hardware-in-the-loop testing at the Guided Weapons Evaluation Facility (GWEF) at Eglin Air Force Base, Florida. This paper will describe the process used to generate the high-resolution (1-foot) database of ten sites totaling over 20 square kilometers of the Eglin range. this process involved generating digital elevation maps from stereo aerial imagery and classifying ground cover material using the spectral content. These databases were then optimized for real-time operation at 90 Hz.

Looped star polymers show conformational transition from spherical to flat toroidal shapes.

PubMed

Reiss, Pascal; Fritsche, Miriam; Heermann, Dieter W

2011-11-01

Inspired by the topological organization of the circular Escherichia coli chromosome, which is compacted by separate domains, we study a polymer architecture consisting of a central ring to which either looped or linear side chains are grafted. A shape change from a spherical to a toroidal organization takes place as soon as the inner ring becomes large enough for the attached arms to fit within its circumference. Building up a torus, the system flattens, depending on the effective bending rigidity of the chain induced by entropic repulsion of the attached loops and, to a lesser extent, linear arms. Our results suggest that the natural formation of a toroidal structure with a decreased amount of writhe induced by a specific underlying topology could be one driving force, among others, that nature exploits to ensure proper packaging of the genetic material within a rod-shaped, bacterial envelope.

Documentation of programs that compute 1) static tilts for a spatially variable slip distribution, and 2) quasi-static tilts produced by an expanding dislocation loop with a spatially variable slip distribution

USGS Publications Warehouse

McHugh, Stuart

1976-01-01

The material in this report is concerned with the effects of a vertically oriented rectangular dislocation loop on the tilts observed at the free surface of an elastic half-space. Part I examines the effect of a spatially variable static strike-slip distribution across the slip surface. The tilt components as a function of distance parallel, or perpendicular, to the strike of the slip surface are displayed for different slip-versus-distance profiles. Part II examines the effect of spatially and temporally variable slip distributions across the dislocation loop on the quasi-static tilts at the free surface of an elastic half space. The model discussed in part II may be used to generate theoretical tilt versus time curves produced by creep events.

Study of fingerprint patterns to evaluate the role of dermatoglyphics in early detection of bronchial asthma

PubMed Central

Singh, Shiva; Khurana, Alkesh Kumar; Harode, Hemant Ashish; Tripathi, Apoorva; Pakhare, Abhijit; Chaware, Prashant

2016-01-01

Background: Dermatoglyphics and bronchial asthma (BA) are both influenced by genetic factors. Hence, we assessed the diagnostic potential of correlation between fingerprint pattern and BA. Materials and Methods: The study was carried out in out-patient Department of Pulmonary Medicine of All India Institute of Medical Sciences Bhopal. It included 36 patients of BA and 50 nonasthmatic individuals as controls. The following parameters were studied and analyzed: (a) Whorls, (b) arches, (c) radial loops, (d) ulnar loops, (e) the absolute finger ridge count (AFRC), (f) total finger ridge count (TFRC). Results: A significant decrease in the mean value of the arches and increase in the mean value of the ulnar loops were observed in BA patients compared to the control group. The mean values of TFRC, AFRC, and whorls were similar in both groups. Conclusion: Evaluation of dermatoglyphic patterns may be useful in identifying patients prone to developing BA. PMID:27003968

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

Natesan, K.; Momozaki, Y.; Li, M.

This report gives a description of the activities in design, fabrication, construction, and assembling of a pumped sodium loop for the sodium compatibility studies on advanced structural materials. The work is the Argonne National Laboratory (ANL) portion of the effort on the work project entitled, 'Sodium Compatibility of Advanced Fast Reactor Materials,' and is a part of Advanced Materials Development within the Reactor Campaign. The objective of this project is to develop information on sodium corrosion compatibility of advanced materials being considered for sodium reactor applications. This report gives the status of the sodium pumped loop at Argonne National Laboratory,more » the specimen details, and the technical approach to evaluate the sodium compatibility of advanced structural alloys. This report is a deliverable from ANL in FY2010 (M2GAN10SF050302) under the work package G-AN10SF0503 'Sodium Compatibility of Advanced Fast Reactor Materials.' Two reports were issued in 2009 (Natesan and Meimei Li 2009, Natesan et al. 2009) which examined the thermodynamic and kinetic factors involved in the purity of liquid sodium coolant for sodium reactor applications as well as the design specifications for the ANL pumped loop for testing advanced structural materials. Available information was presented on solubility of several metallic and nonmetallic elements along with a discussion of the possible mechanisms for the accumulation of impurities in sodium. That report concluded that the solubility of many metals in sodium is low (<1 part per million) in the temperature range of interest in sodium reactors and such trace amounts would not impact the mechanical integrity of structural materials and components. The earlier report also analyzed the solubility and transport mechanisms of nonmetallic elements such as oxygen, nitrogen, carbon, and hydrogen in laboratory sodium loops and in reactor systems such as Experimental Breeder Reactor-II, Fast Flux Test Facility, and Clinch River Breeder Reactor. Among the nonmetallic elements discussed, oxygen is deemed controllable and its concentration in sodium can be maintained in sodium for long reactor life by using cold-trap method. It was concluded that among the cold-trap and getter-trap methods, the use of cold trap is sufficient to achieve oxygen concentration of the order of 1 part per million. Under these oxygen conditions in sodium, the corrosion performance of structural materials such as austenitic stainless steels and ferritic steels will be acceptable at a maximum core outlet sodium temperature of {approx}550 C. In the current sodium compatibility studies, the oxygen concentration in sodium will be controlled and maintained at {approx}1 ppm by controlling the cold trap temperature. The oxygen concentration in sodium in the forced convection sodium loop will be controlled and monitored by maintaining the cold trap temperature in the range of 120-150 C, which would result in oxygen concentration in the range of 1-2 ppm. Uniaxial tensile specimens are being exposed to flowing sodium and will be retrieved and analyzed for corrosion and post-exposure tensile properties. Advanced materials for sodium exposure include austenitic alloy HT-UPS and ferritic-martensitic steels modified 9Cr-1Mo and NF616. Among the nonmetallic elements in sodium, carbon was assessed to have the most influence on structural materials since carbon, as an impurity, is not amenable to control and maintenance by any of the simple purification methods. The dynamic equilibrium value for carbon in sodium systems is dependent on several factors, details of which were discussed in the earlier report. The current sodium compatibility studies will examine the role of carbon concentration in sodium on the carburization-decarburization of advanced structural materials at temperatures up to 650 C. Carbon will be added to the sodium by exposure of carbon-filled iron tubes, which over time will enable carbon to diffuse through iron and dissolve into sodium. The method enables addition of dissolved carbon (without carbon particulates) in sodium that is of interest for materials compatibility evaluation. The removal of carbon from the sodium will be accomplished by exposing carbon-gettering alloys such as refractory metals that have a high partitioning coefficient for carbon and also precipitate carbides, thereby decreasing the carbon concentration in sodium.« less

Solar Scientist Confirm Existence of Flux Ropes on the Sun

NASA Image and Video Library

2017-12-08

Caption: This is an image of magnetic loops on the sun, captured by NASA's Solar Dynamics Observatory on July 18, 2012. It has been processed to highlight the edges of each loop to make the structure more clear. A series of loops such as this is known as a flux rope, and these lie at the heart of eruptions on the sun known as coronal mass ejections (CMEs.) This is the first time scientists were able to discern the timing of a flux rope's formation. Credit: NASA/Goddard Space Flight Center/SDO ---- On July 18, 2012, a fairly small explosion of light burst off the lower right limb of the sun. Such flares often come with an associated eruption of solar material, known as a coronal mass ejection or CME – but this one did not. Something interesting did happen, however. Magnetic field lines in this area of the sun's atmosphere, the corona, began to twist and kink, generating the hottest solar material – a charged gas called plasma – to trace out the newly-formed slinky shape. The plasma glowed brightly in extreme ultraviolet images from the Atmospheric Imaging Assembly (AIA) aboard NASA’s Solar Dynamics Observatory (SDO) and scientists were able to watch for the first time the very formation of something they had long theorized was at the heart of many eruptive events on the sun: a flux rope. Eight hours later, on July 19, the same region flared again. This time the flux rope's connection to the sun was severed, and the magnetic fields escaped into space, dragging billions of tons of solar material along for the ride -- a classic CME. "Seeing this structure was amazing," says Angelos Vourlidas, a solar scientist at the Naval Research Laboratory in Washington, D.C. "It looks exactly like the cartoon sketches theorists have been drawing of flux ropes since the 1970s. It was a series of figure eights lined up to look like a giant slinky on the sun." To read more about this new discovery go to: 1.usa.gov/14UHsTt NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

Solar Scientist Confirm Existence of Flux Ropes on the Sun

NASA Image and Video Library

2017-12-08

Caption: This is an image of magnetic loops on the sun, captured by NASA's Solar Dynamics Observatory (SDO). It has been processed to highlight the edges of each loop to make the structure more clear. A series of loops such as this is known as a flux rope, and these lie at the heart of eruptions on the sun known as coronal mass ejections (CMEs.) This is the first time scientists were able to discern the timing of a flux rope's formation. (Blended 131 Angstrom and 171 Angstrom images of July 19, 2012 flare and CME.) Credit: NASA/Goddard Space Flight Center/SDO ---- On July 18, 2012, a fairly small explosion of light burst off the lower right limb of the sun. Such flares often come with an associated eruption of solar material, known as a coronal mass ejection or CME – but this one did not. Something interesting did happen, however. Magnetic field lines in this area of the sun's atmosphere, the corona, began to twist and kink, generating the hottest solar material – a charged gas called plasma – to trace out the newly-formed slinky shape. The plasma glowed brightly in extreme ultraviolet images from the Atmospheric Imaging Assembly (AIA) aboard NASA’s Solar Dynamics Observatory (SDO) and scientists were able to watch for the first time the very formation of something they had long theorized was at the heart of many eruptive events on the sun: a flux rope. Eight hours later, on July 19, the same region flared again. This time the flux rope's connection to the sun was severed, and the magnetic fields escaped into space, dragging billions of tons of solar material along for the ride -- a classic CME. "Seeing this structure was amazing," says Angelos Vourlidas, a solar scientist at the Naval Research Laboratory in Washington, D.C. "It looks exactly like the cartoon sketches theorists have been drawing of flux ropes since the 1970s. It was a series of figure eights lined up to look like a giant slinky on the sun." To read more about this new discovery go to: 1.usa.gov/14UHsTt NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

Space life sciences: Programs and projects

NASA Technical Reports Server (NTRS)

1989-01-01

NASA space life science activities are outlined. Brief, general descriptions are given of research in the areas of biomedical research, space biology, closed loop life support systems, exobiology, and biospherics.

Summary report for the FY-2015 SACSESS Collaboration

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

Peterman, Dean Richard; Mincher, Bruce Jay

2015-09-01

During FY-2015, a collaborative research program was established by the Department of Energy-Nuclear Energy (DOE-NE) Material Recovery and Waste Form Development program and the European Union (EU) Safety of Actinide Separation Processes (SACSESS) program. One component of this collaboration was the evaluation of the radiolytic stability of a Selective ActiNide Extraction (SANEX) separation which utilized a TODGA-based organic solvent and an aqueous phase containing the hydrophilic complexing reagent, SO3-Ph-BTP. To best simulate process conditions, this experiment was irradiated in the radiolysis/hydrolysis test loop located at the Idaho National Laboratory. The effect of irradiation on a SACSESS program iSANEX formulation containingmore » a TODGA-based organic phase and a BTP-based aqueous phase was investigated using irradiations at INL in static and test loop modes. When irradiated in contact with only the acidic aqueous phase, the TODGA organic solution maintained excellent extraction performance of americium, cerium and europium to a maximum absorbed dose of nearly 0.9 MGy. When the aqueous phase was changed to that containing the aqueous soluble BTP, the irradiated aqueous phase showed a dramatic color change, but this does not appear to have adverse effects on solvent extraction performance. Only minor increases in distribution ratios for both the lanthanides and actinide were measured, and the separation factors were essentially unchanged to a maximum absorbed dose of 174 kGy. The determination of the americium, cerium, and europium distribution ratios for the remaining SACSESS test loop samples will be completed in the near future. The analysis of stable metals concentration in the the irradiated aqueous and organic phases will be completed shortly.« less

Material Studies Related to the Use of NaK Heat Exchangers Coupled to Stirling Heater Heads

NASA Technical Reports Server (NTRS)

Locci, Ivan E.; Bowman, Cheryl L.; Geng, Steven M.; Robbie, Malcolm G.

2011-01-01

NASA has been supporting design studies and technology development that could provide power to an outpost on the Moon, Mars, or an asteroid. Technology development efforts have included fabrication and evaluation of components used in a Stirling engine power conversion system. Destructive material evaluation was performed on a NaK shell heat exchanger that was developed by the NASA Glenn Research Center (GRC) and integrated with a commercial 1 kWe Stirling convertor from Sunpower Incorporated. The NaK Stirling test demonstrated Stirling convertor electrical power generation using a pumped liquid metal heat source under thermal conditions that represent the heat exchanger liquid metal loop in a Fission Power Systems (FPS) reactor. The convertors were operated for a total test time of 66 hr at a maximum temperature of 823 K. After the test was completed and NaK removed, the heat exchanger assembly was sectioned to evaluate any material interactions with the flowing liquid metal. Several dissimilar-metal braze joint options, crucial for the heat exchanger transfer path, were also investigated. A comprehensive investigation was completed and lessons learned for future heat exchanger development efforts are discussed.

Quality- and dilution losses in the recycling of ferrous materials from end-of-life passenger cars: input-output analysis under explicit consideration of scrap quality.

PubMed

Nakamura, Shinichiro; Kondo, Yasushi; Matsubae, Kazuyo; Nakajima, Kenichi; Tasaki, Tomohiro; Nagasaka, Tetsuya

2012-09-04

Metals can in theory be infinitely recycled in a closed-loop without any degradation in quality. In reality, however, open-loop recycling is more typical for metal scrap recovered from end-of-life (EoL) products because mixing of different metal species results in scrap quality that no longer matches the originals. Further losses occur when meeting the quality requirement of the target product requires dilution of the secondary material by adding high purity materials. Standard LCA usually does not address these losses. This paper presents a novel approach to quantifying quality- and dilution losses, by means of hybrid input-output analysis. We focus on the losses associated with the recycling of ferrous materials from end-of-life vehicle (ELV) due to the mixing of copper, a typical contaminant in steel recycling. Given the quality of scrap in terms of copper density, the model determines the ratio by which scrap needs to be diluted in an electric arc furnace (EAF), and the amount of demand for EAF steel including those quantities needed for dilution. Application to a high-resolution Japanese IO table supplemented with data on ferrous materials including different grades of scrap indicates that a nationwide avoidance of these losses could result in a significant reduction of CO(2) emissions.

Piloted Parameter Identification Flight Test Maneuvers for Closed Loop Modeling of the F-18 High Alpha Research Vehicle (HARV)

NASA Technical Reports Server (NTRS)

Morelli, Eugene A.

1996-01-01

Flight test maneuvers are specified for the F-18 High Alpha Research Vehicle (HARV). The maneuvers were designed for closed loop parameter identification purposes, specifically for longitudinal and lateral linear model parameter estimation at 5, 20, 30, 45, and 60 degrees angle of attack, using the NASA 1A control law. Each maneuver is to be realized by the pilot applying square wave inputs to specific pilot station controls. Maneuver descriptions and complete specifications of the time/amplitude points defining each input are included, along with plots of the input time histories.

Lattice strain in irradiated materials unveils a prevalent defect evolution mechanism

NASA Astrophysics Data System (ADS)

Debelle, Aurélien; Crocombette, Jean-Paul; Boulle, Alexandre; Chartier, Alain; Jourdan, Thomas; Pellegrino, Stéphanie; Bachiller-Perea, Diana; Carpentier, Denise; Channagiri, Jayanth; Nguyen, Tien-Hien; Garrido, Frédérico; Thomé, Lionel

2018-01-01

Modification of materials using ion beams has become a widespread route to improve or design materials for advanced applications, from ion doping for microelectronic devices to emulation of nuclear reactor environments. Yet, despite decades of studies, major issues regarding ion/solid interactions are not solved, one of them being the lattice-strain development process in irradiated crystals. In this work, we address this question using a consistent approach that combines x-ray diffraction (XRD) measurements with both molecular dynamics (MD) and rate equation cluster dynamics (RECD) simulations. We investigate four distinct materials that differ notably in terms of crystalline structure and nature of the atomic bonding. We demonstrate that these materials exhibit a common behavior with respect to the strain development process. In fact, a strain build-up followed by a strain relaxation is observed in the four investigated cases. The strain variation is unambiguously ascribed to a change in the defect configuration, as revealed by MD simulations. Strain development is due to the clustering of interstitial defects into dislocation loops, while the strain release is associated with the disappearance of these loops through their integration into a network of dislocation lines. RECD calculations of strain depth profiles, which are in agreement with experimental data, indicate that the driving force for the change in the defect nature is the defect clustering process. This study paves the way for quantitative predictions of the microstructure changes in irradiated materials.

Closed-Loop HIRF Experiments Performed on a Fault Tolerant Flight Control Computer

NASA Technical Reports Server (NTRS)

Belcastro, Celeste M.

1997-01-01

ABSTRACT Closed-loop HIRF experiments were performed on a fault tolerant flight control computer (FCC) at the NASA Langley Research Center. The FCC used in the experiments was a quad-redundant flight control computer executing B737 Autoland control laws. The FCC was placed in one of the mode-stirred reverberation chambers in the HIRF Laboratory and interfaced to a computer simulation of the B737 flight dynamics, engines, sensors, actuators, and atmosphere in the Closed-Loop Systems Laboratory. Disturbances to the aircraft associated with wind gusts and turbulence were simulated during tests. Electrical isolation between the FCC under test and the simulation computer was achieved via a fiber optic interface for the analog and discrete signals. Closed-loop operation of the FCC enabled flight dynamics and atmospheric disturbances affecting the aircraft to be represented during tests. Upset was induced in the FCC as a result of exposure to HIRF, and the effect of upset on the simulated flight of the aircraft was observed and recorded. This paper presents a description of these closed- loop HIRF experiments, upset data obtained from the FCC during these experiments, and closed-loop effects on the simulated flight of the aircraft.

Run-time parallelization and scheduling of loops

NASA Technical Reports Server (NTRS)

Saltz, Joel H.; Mirchandaney, Ravi; Baxter, Doug

1988-01-01

The class of problems that can be effectively compiled by parallelizing compilers is discussed. This is accomplished with the doconsider construct which would allow these compilers to parallelize many problems in which substantial loop-level parallelism is available but cannot be detected by standard compile-time analysis. We describe and experimentally analyze mechanisms used to parallelize the work required for these types of loops. In each of these methods, a new loop structure is produced by modifying the loop to be parallelized. We also present the rules by which these loop transformations may be automated in order that they be included in language compilers. The main application area of the research involves problems in scientific computations and engineering. The workload used in our experiment includes a mixture of real problems as well as synthetically generated inputs. From our extensive tests on the Encore Multimax/320, we have reached the conclusion that for the types of workloads we have investigated, self-execution almost always performs better than pre-scheduling. Further, the improvement in performance that accrues as a result of global topological sorting of indices as opposed to the less expensive local sorting, is not very significant in the case of self-execution.

[Development of medical supplies management system].

PubMed

Zhong, Jianping; Shen, Beijun; Zhu, Huili

2012-11-01

This paper adopts advanced information technology to manage medical supplies, in order to improve the medical supplies management level and reduce material cost. It develops a Medical Supplies Management System with B/S and C/S mixed structure, optimizing material management process, building large equipment performance evaluation model, providing interface solution with HIS, and realizing real-time information briefing of high value material's consumption. The medical materials are managed during its full life-cycle. The material consumption of the clinical departments is monitored real-timely. Through the closed-loop management with pre-event budget, mid-event control and after-event analysis, it realizes the final purpose of management yielding benefit.

Application of phase matching autofocus in airborne long-range oblique photography camera

NASA Astrophysics Data System (ADS)

Petrushevsky, Vladimir; Guberman, Asaf

2014-06-01

The Condor2 long-range oblique photography (LOROP) camera is mounted in an aerodynamically shaped pod carried by a fast jet aircraft. Large aperture, dual-band (EO/MWIR) camera is equipped with TDI focal plane arrays and provides high-resolution imagery of extended areas at long stand-off ranges, at day and night. Front Ritchey-Chretien optics is made of highly stable materials. However, the camera temperature varies considerably in flight conditions. Moreover, a composite-material structure of the reflective objective undergoes gradual dehumidification in dry nitrogen atmosphere inside the pod, causing some small decrease of the structure length. The temperature and humidity effects change a distance between the mirrors by just a few microns. The distance change is small but nevertheless it alters the camera's infinity focus setpoint significantly, especially in the EO band. To realize the optics' resolution potential, the optimal focus shall be constantly maintained. In-flight best focus calibration and temperature-based open-loop focus control give mostly satisfactory performance. To get even better focusing precision, a closed-loop phase-matching autofocus method was developed for the camera. The method makes use of an existing beamsharer prism FPA arrangement where aperture partition exists inherently in an area of overlap between the adjacent detectors. The defocus is proportional to an image phase shift in the area of overlap. Low-pass filtering of raw defocus estimate reduces random errors related to variable scene content. Closed-loop control converges robustly to precise focus position. The algorithm uses the temperature- and range-based focus prediction as an initial guess for the closed-loop phase-matching control. The autofocus algorithm achieves excellent results and works robustly in various conditions of scene illumination and contrast.

Embedded Meta-Material Antennas

DTIC Science & Technology

2009-01-31

influence of the overall capacitance . Based on the tunable SRRs, we designed a tunable loop antenna with SRRs and HPTs as tuning elements. In this case, we...are those of the authors) and should not be construed as an official Department of the Army position, policy or decision, unless so designated by...single aperture, which can provide significant miniaturization and flexibility to the entire system. To design such miniaturized antennas, new materials

Engineering the Mechanical Properties of Polymer Networks with Precise Doping of Primary Defects.

PubMed

Chan, Doreen; Ding, Yichuan; Dauskardt, Reinhold H; Appel, Eric A

2017-12-06

Polymer networks are extensively utilized across numerous applications ranging from commodity superabsorbent polymers and coatings to high-performance microelectronics and biomaterials. For many applications, desirable properties are known; however, achieving them has been challenging. Additionally, the accurate prediction of elastic modulus has been a long-standing difficulty owing to the presence of loops. By tuning the prepolymer formulation through precise doping of monomers, specific primary network defects can be programmed into an elastomeric scaffold, without alteration of their resulting chemistry. The addition of these monomers that respond mechanically as primary defects is used both to understand their impact on the resulting mechanical properties of the materials and as a method to engineer the mechanical properties. Indeed, these materials exhibit identical bulk and surface chemistry, yet vastly different mechanical properties. Further, we have adapted the real elastic network theory (RENT) to the case of primary defects in the absence of loops, thus providing new insights into the mechanism for material strength and failure in polymer networks arising from primary network defects, and to accurately predict the elastic modulus of the polymer system. The versatility of the approach we describe and the fundamental knowledge gained from this study can lead to new advancements in the development of novel materials with precisely defined and predictable chemical, physical, and mechanical properties.

Inverted Resistance Measurements as a Method for Characterizing the Bulk and Surface Conductivities of Three-Dimensional Topological Insulators

NASA Astrophysics Data System (ADS)

Eo, Y. S.; Sun, K.; Kurdak, ć.; Kim, D.-J.; Fisk, Z.

2018-04-01

We introduce a resistance measurement method that is useful in characterizing materials with both surface and bulk conduction, such as three-dimensional topological insulators. The transport geometry for this resistance measurement configuration consists of one current lead as a closed loop that fully encloses the other current lead on the surface, and two voltage leads that are both placed outside the loop. We show that, in the limit where the transport is dominated by the surface conductivity of the material, the four-terminal resistance measured from such a transport geometry is proportional to σb/σs2, where σb and σs are the bulk and surface conductivities of the material, respectively. We call this type of measurement inverted resistance measurement, as the resistance scales inversely with the bulk resistivity. We discuss possible implementations of this method by performing numerical calculations on different geometries and introduce strategies to extract the bulk and surface conductivities. We also demonstrate inverted resistance measurements on SmB6 , a topological Kondo insulator, using both single-sided and coaxially aligned double-sided Corbino disk transport geometries. Using this method, we are able to measure the bulk conductivity, even at low temperatures, where the bulk conduction is much smaller than the surface conduction in this material.

Networks of channels for self-healing composite materials

NASA Astrophysics Data System (ADS)

Bejan, A.; Lorente, S.; Wang, K.-M.

2006-08-01

This is a fundamental study of how to vascularize a self-healing composite material so that healing fluid reaches all the crack sites that may occur randomly through the material. The network of channels is built into the material and is filled with pressurized healing fluid. When a crack forms, the pressure drops at the crack site and fluid flows from the network into the crack. The objective is to discover the network configuration that is capable of delivering fluid to all the cracks the fastest. The crack site dimension and the total volume of the channels are fixed. It is argued that the network must be configured as a grid and not as a tree. Two classes of grids are considered and optimized: (i) grids with one channel diameter and regular polygonal loops (square, triangle, hexagon) and (ii) grids with two channel sizes. The best architecture of type (i) is the grid with triangular loops. The best architecture of type (ii) has a particular (optimal) ratio of diameters that departs from 1 as the crack length scale becomes smaller than the global scale of the vascularized structure from which the crack draws its healing fluid. The optimization of the ratio of channel diameters cuts in half the time of fluid delivery to the crack.

Mercury regulation, fate, transport, transformation, and abatement within cement manufacturing facilities: review.

PubMed

Sikkema, Joel K; Alleman, James E; Ong, Say Kee; Wheelock, Thomas D

2011-09-15

The USEPA's 2010 mercury rule, which would reduce emissions from non-hazardous waste burning cement manufacturing facilities by an estimated 94%, represents a substantial regulatory challenge for the industry. These regulations, based on the performance of facilities that benefit from low concentrations of mercury in their feedstock and fuel inputs (e.g., limestone concentration was less than 25 ppb at each facility), will require non-compliant facilities to develop innovative controls. Control development is difficult because each facility's emissions must be assessed and simple correlation to mercury concentrations in limestone or an assumption of 'typically observed' mercury concentrations in inputs are unsupported by available data. Furthermore, atmospheric emissions are highly variable due to an internal control mechanism that captures and loops mercury between the high-temperature kiln and low-temperature raw materials mill. Two models have been reported to predict emissions; however, they have not been benchmarked against data from the internal components that capture mercury and do not distinguish between mercury species, which have different sorption and desorption properties. Control strategies include technologies applied from other industries and technologies developed specifically for cement facilities. Reported technologies, listed from highest to lowest anticipated mercury removal, include purge of collected dust or raw meal, changes in feedstocks and fuels, wet scrubbing, cleaning of mercury enriched dust, dry sorbent injection, and dry and semi-dry scrubbing. The effectiveness of these technologies is limited by an inadequate understanding of sorption, desorption, and mercury species involved in internal loop mercury control. To comply with the mercury rule and to improve current mercury control technologies and practices, research is needed to advance fundamental knowledge regarding mercury species sorption and desorption dynamics on materials within cement facilities. Copyright © 2011 Elsevier B.V. All rights reserved.

Reporting Research Results Effectively

ERIC Educational Resources Information Center

Volkwein, J. Fredericks

2010-01-01

Assessment research is at its best when it packages research results and data so that they can be digested by multiple audiences. Too many assessment researchers spend all their efforts planning and executing the research project with little attention to closing the loop at the end. If assessment findings are not communicated effectively, the…

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

Evans, J.H.; Chipley, K.K.; Nelms, H.A.

An evaluation of the ORNL loop transport cask demonstrating its compliance with the regulations governing the transportation of radioactive and fissile materials is presented. A previous review of the cask is updated to demonstrate compliance with current regulations, to present current procedures, and to reflect the more recent technology.

40 CFR 63.8802 - What methods must I use to demonstrate compliance with the emission limitation for loop slitter...

Code of Federal Regulations, 2010 CFR

2010-07-01

... Hazardous Air Pollutants: Flexible Polyurethane Foam Fabrication Operations Testing and Initial Compliance... for each material used in your foam fabrication operations, you must use one of the options in...

40 CFR 63.8802 - What methods must I use to demonstrate compliance with the emission limitation for loop slitter...

Code of Federal Regulations, 2013 CFR

2013-07-01

... Hazardous Air Pollutants: Flexible Polyurethane Foam Fabrication Operations Testing and Initial Compliance... for each material used in your foam fabrication operations, you must use one of the options in...

40 CFR 63.8802 - What methods must I use to demonstrate compliance with the emission limitation for loop slitter...

Code of Federal Regulations, 2011 CFR

2011-07-01

... Hazardous Air Pollutants: Flexible Polyurethane Foam Fabrication Operations Testing and Initial Compliance... for each material used in your foam fabrication operations, you must use one of the options in...

40 CFR 63.8802 - What methods must I use to demonstrate compliance with the emission limitation for loop slitter...

Code of Federal Regulations, 2012 CFR

2012-07-01

... Hazardous Air Pollutants: Flexible Polyurethane Foam Fabrication Operations Testing and Initial Compliance... for each material used in your foam fabrication operations, you must use one of the options in...

40 CFR 63.8802 - What methods must I use to demonstrate compliance with the emission limitation for loop slitter...

Code of Federal Regulations, 2014 CFR

2014-07-01

... Hazardous Air Pollutants: Flexible Polyurethane Foam Fabrication Operations Testing and Initial Compliance... for each material used in your foam fabrication operations, you must use one of the options in...

To BG or not to BG: Background Subtraction for EIT Coronal Loops

NASA Astrophysics Data System (ADS)

Beene, J. E.; Schmelz, J. T.

2003-05-01

One of the few observational tests for various coronal heating models is to determine the temperature profile along coronal loops. Since loops are such an abundant coronal feature, this method originally seemed quite promising - that the coronal heating problem might actually be solved by determining the temperature as a function of arc length and comparing these observations with predictions made by different models. But there are many instruments currently available to study loops, as well as various techniques used to determine their temperature characteristics. Consequently, there are many different, mostly conflicting temperature results. We chose data for ten coronal loops observed with the Extreme ultraviolet Imaging Telescope (EIT), and chose specific pixels along each loop, as well as corresponding nearby background pixels where the loop emission was not present. Temperature analysis from the 171-to-195 and 195-to-284 angstrom image ratios was then performed on three forms of the data: the original data alone, the original data with a uniform background subtraction, and the original data with a pixel-by-pixel background subtraction. The original results show loops of constant temperature, as other authors have found before us, but the 171-to-195 and 195-to-284 results are significantly different. Background subtraction does not change the constant-temperature result or the value of the temperature itself. This does not mean that loops are isothermal, however, because the background pixels, which are not part of any contiguous structure, also produce a constant-temperature result with the same value as the loop pixels. These results indicate that EIT temperature analysis should not be trusted, and the isothermal loops that result from EIT (and TRACE) analysis may be an artifact of the analysis process. Solar physics research at the University of Memphis is supported by NASA grants NAG5-9783 and NAG5-12096.

Microstructure and Property Evolution in Advanced Cladding and Duct Materials Under Long-Term and Elevated Temperature Irradiation: Modeling and Experimental Investigation

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

Wirth, Brian; Morgan, Dane; Kaoumi, Djamel

2013-12-01

The in-service degradation of reactor core materials is related to underlying changes in the irradiated microstructure. During reactor operation, structural components and cladding experience displacement of atoms by collisions with neutrons at temperatures at which the radiation-induced defects are mobile, leading to microstructure evolution under irradiation that can degrade material properties. At the doses and temperatures relevant to fast reactor operation, the microstructure evolves by dislocation loop formation and growth, microchemistry changes due to radiation-induced segregation, radiation-induced precipitation, destabilization of the existing precipitate structure, and in some cases, void formation and growth. These processes do not occur independently; rather, theirmore » evolution is highly interlinked. Radiationinduced segregation of Cr and existing chromium carbide coverage in irradiated alloy T91 track each other closely. The radiation-induced precipitation of Ni-Si precipitates and RIS of Ni and Si in alloys T91 and HCM12A are likely related. Neither the evolution of these processes nor their coupling is understood under the conditions required for materials performance in fast reactors (temperature range 300-600°C and doses beyond 200 dpa). Further, predictive modeling is not yet possible as models for microstructure evolution must be developed along with experiments to characterize these key processes and provide tools for extrapolation. To extend the range of operation of nuclear fuel cladding and structural materials in advanced nuclear energy and transmutation systems to that required for the fast reactor, the irradiation-induced evolution of the microstructure, microchemistry, and the associated mechanical properties at relevant temperatures and doses must be understood. Predictive modeling relies on an understanding of the physical processes and also on the development of microstructure and microchemical models to describe their evolution under irradiation. This project will focus on modeling microstructural and microchemical evolution of irradiated alloys by performing detailed modeling of such microstructure evolution processes coupled with well-designed in situ experiments that can provide validation and benchmarking to the computer codes. The broad scientific and technical objectives of this proposal are to evaluate the microstructure and microchemical evolution in advanced ferritic/martensitic and oxide dispersion strengthened (ODS) alloys for cladding and duct reactor materials under long-term and elevated temperature irradiation, leading to improved ability to model structural materials performance and lifetime. Specifically, we propose four research thrusts, namely Thrust 1: Identify the formation mechanism and evolution for dislocation loops with Burgers vector of a<100> and determine whether the defect microstructure (predominately dislocation loop/dislocation density) saturates at high dose. Thrust 2: Identify whether a threshold irradiation temperature or dose exists for the nucleation of growing voids that mark the beginning of irradiation-induced swelling, and begin to probe the limits of thermal stability of the tempered Martensitic structure under irradiation. Thrust 3: Evaluate the stability of nanometer sized Y- Ti-O based oxide dispersion strengthened (ODS) particles at high fluence/temperature. Thrust 4: Evaluate the extent to which precipitates form and/or dissolve as a function of irradiation temperature and dose, and how these changes are driven by radiation induced segregation and microchemical evolutions and determined by the initial microstructure.« less

Plasma reactor waste management systems

NASA Technical Reports Server (NTRS)

Ness, Robert O., Jr.; Rindt, John R.; Ness, Sumitra R.

1992-01-01

The University of North Dakota is developing a plasma reactor system for use in closed-loop processing that includes biological, materials, manufacturing, and waste processing. Direct-current, high-frequency, or microwave discharges will be used to produce plasmas for the treatment of materials. The plasma reactors offer several advantages over other systems, including low operating temperatures, low operating pressures, mechanical simplicity, and relatively safe operation. Human fecal material, sunflowers, oats, soybeans, and plastic were oxidized in a batch plasma reactor. Over 98 percent of the organic material was converted to gaseous products. The solids were then analyzed and a large amount of water and acid-soluble materials were detected. These materials could possibly be used as nutrients for biological systems.

In-Situ Production of Solar Power Systems for Exploration

NASA Technical Reports Server (NTRS)

Curreri, Peter A.; Criswell, David R.

1999-01-01

Current proposals for developing an extended human presence, beyond space stations, on the Moon and Mars increasingly consider the processing of non-terrestrial materials essential for keeping the Earth launch burden reasonable. Utilization of in-situ resources for construction of lunar and Mars bases will initially require assessment of resource availability followed by the development of economically acceptable and technically feasible extractive processes. In regard to materials processing and fabrication the lower gravity level on the Moon (0.125 g) and Mars (0.367 g) will dramatically change the presently accepted hierarchy of materials in terms of specific properties, a factor which must be understood and exploited. Furthermore, significant changes are expected in the behavior of liquid materials during processing. In casting, for example, mold filling and associated solidification processes have to be reevaluated. Finally microstructural development and therefore material properties, presently being documented through on-going research in microgravity science and applications, needs to be understood and scaled to the reduced gravity environments. One of the most important elements of a human planetary base is power production. Lunar samples and geophysical measurements returned by the Apollo missions provide detailed data on the composition and physical characteristics of the lunar materials and environment. Based on this knowledge and extrapolations of terrestrial industrial experience it is clear that several types of solar-to-electric converters can be manufactured on the Moon. It is conceivable that well over 90% of a solar-to- electric power system could be made from lunar materials. Production and utilization of photovoltaic devices for solar energy production on Earth is primarily driven by the market economy. On Earth a production plant for photovoltaic devices is intimately linked to the planets massive industrial base. A selection of off the shelf refined materials are available as well as cheap fast transportation on demand. The processes takes place (except for the few seconds reprieve in shot towers etc.) under one gravity, with solar radiation significantly modulated by weather, and under conditions where one atmosphere is free and high vacuum is cumbersome and expensive. Off Earth, on lunar or Mars bases, the cost of photovoltaic power is driven by transport costs - Earth launch, deep space transport, landing on the planetary surface. Thus there is a premium for processes that are materials self-sufficient or for closed loop in-situ processes. The lack of differentiated ores on the Moon, and lack of explored minerals on Mars and interplanetary space give a premium to universal/non-ore-specific mineral extractive processes. Initially a semiconductor/photovoltaic production facility will build on no conveniently located industrial base, further increasing the premium on closed loop self sufficient processes.

CLOSED-LOOP TREATMENT OF ELECTROLYTIC AND ELECTROLESS NICKEL RINSE WATER BY POINT-OF-USE ION EXCHANGE: A CASE STUDY.

EPA Science Inventory

Closed-Loop Treatment of Electrolytic and Electroless Nickel Rinse Water by Point-Of-Use Ion Exchange: A Case Study.

Dave Szlag1, Joe Leonhardt2, Albert Foster1, Mike Goss1 and Paul Bolger1.
1 U.S. EPA, National Risk Management Research Laboratory, 26 W. M. L. King D...

[Research on the Clinical Alarm Management Mechanism Based on Closed-loop Control Theory].

PubMed

Lin, Zhongkuan; Zheng, Kun; Shen, Yunming; Wu, Yunyun

2018-05-30

This paper proposes a clinical alarm management system based on the theory of the closed loop control. The alarm management mechanism can be divided into the expected standard, improving execution rule, rule execution, medical devices with alarm functions, results analysis strategy and the output link. And, we make relevant application and discussion. Results showed that the mechanism can be operable and effective.

Clearing the Air: New Approaches to Life Support in Outer Space

NASA Technical Reports Server (NTRS)

Knox, J.; Howard, D.

2008-01-01

This article reports on research into atmospheric revitalization systems for long-term space travel and the use ofCOMSOL Multiphysics to understand how structured sorbents can be used to improve the performance of adsorption processes via thermal management. We are developing the next generation of atmosphere revitalization systems, which will reach for new levels of resource conservation via a high percentage of loop closure. For example, a high percentage of carbon dioxide, exhaled by crew, can be converted via reaction to drinking water, closing the loop from human metabolic waste to supply. Adsorption processes play a lead role in these new/closed loop systems.

Experiment Needs and Facilities Study Appendix A Transient Reactor Test Facility (TREAT) Upgrade

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

None

The TREAT Upgrade effort is designed to provide significant new capabilities to satisfy experiment requirements associated with key LMFBR Safety Issues. The upgrade consists of reactor-core modifications to supply the physics performance needed for the new experiments, an Advanced TREAT loop with size and thermal-hydraulics capabilities needed for the experiments, associated interface equipment for loop operations and handling, and facility modifications necessary to accommodate operations with the Loop. The costs and schedules of the tasks to be accomplished under the TREAT Upgrade project are summarized. Cost, including contingency, is about 10 million dollars (1976 dollars). A schedule for execution ofmore » 36 months has been established to provide the new capabilities in order to provide timely support of the LMFBR national effort. A key requirement for the facility modifications is that the reactor availability will not be interrupted for more than 12 weeks during the upgrade. The Advanced TREAT loop is the prototype for the STF small-bundle package loop. Modified TREAT fuel elements contain segments of graphite-matrix fuel with graded uranium loadings similar to those of STF. In addition, the TREAT upgrade provides for use of STF-like stainless steel-UO{sub 2} TREAT fuel for tests of fully enriched fuel bundles. This report will introduce the Upgrade study by presenting a brief description of the scope, performance capability, safety considerations, cost schedule, and development requirements. This work is followed by a "Design Description". Because greatly upgraded loop performance is central to the upgrade, a description is given of Advanced TREAT loop requirements prior to description of the loop concept. Performance requirements of the upgraded reactor system are given. An extensive discussion of the reactor physics calculations performed for the Upgrade concept study is provided. Adequate physics performance is essential for performance of experiments with the Advanced TREAT loop, and the stress placed on these calculations reflects this. Additional material on performance and safety is provided. Backup calculations on calculations of plutonium-release limits are described. Cost and schedule information for the Upgrade are presented.« less

Cost Models for MMC Manufacturing Processes

NASA Technical Reports Server (NTRS)

Elzey, Dana M.; Wadley, Haydn N. G.

1996-01-01

The quality cost modeling (QCM) tool is intended to be a relatively simple-to-use device for obtaining a first-order assessment of the quality-cost relationship for a given process-material combination. The QCM curve is a plot of cost versus quality (an index indicating microstructural quality), which is unique for a given process-material combination. The QCM curve indicates the tradeoff between cost and performance, thus enabling one to evaluate affordability. Additionally, the effect of changes in process design, raw materials, and process conditions on the cost-quality relationship can be evaluated. Such results might indicate the most efficient means to obtain improved quality at reduced cost by process design refinements, the implementation of sensors and models for closed loop process control, or improvement in the properties of raw materials being fed into the process. QCM also allows alternative processes for producing the same or similar material to be compared in terms of their potential for producing competitively priced, high quality material. Aside from demonstrating the usefulness of the QCM concept, this is one of the main foci of the present research program, namely to compare processes for making continuous fiber reinforced, metal matrix composites (MMC's). Two processes, low pressure plasma spray deposition and tape casting are considered for QCM development. This document consists of a detailed look at the design of the QCM approach, followed by discussion of the application of QCM to each of the selected MMC manufacturing processes along with results, comparison of processes, and finally, a summary of findings and recommendations.

Bohr's Electron was Problematic for Einstein: String Theory Solved the Problem

NASA Astrophysics Data System (ADS)

Webb, William

2013-04-01

Neils Bohr's 1913 model of the hydrogen electron was problematic for Albert Einstein. Bohr's electron rotates with positive kinetic energies +K but has addition negative potential energies - 2K. The total net energy is thus always negative with value - K. Einstein's special relativity requires energies to be positive. There's a Bohr negative energy conflict with Einstein's positive energy requirement. The two men debated the problem. Both would have preferred a different electron model having only positive energies. Bohr and Einstein couldn't find such a model. But Murray Gell-Mann did! In the 1960's, Gell-Mann introduced his loop-shaped string-like electron. Now, analysis with string theory shows that the hydrogen electron is a loop of string-like material with a length equal to the circumference of the circular orbit it occupies. It rotates like a lariat around its centered proton. This loop-shape has no negative potential energies: only positive +K relativistic kinetic energies. Waves induced on loop-shaped electrons propagate their energy at a speed matching the tangential speed of rotation. With matching wave speed and only positive kinetic energies, this loop-shaped electron model is uniquely suited to be governed by the Einstein relativistic equation for total mass-energy. Its calculated photon emissions are all in excellent agreement with experimental data and, of course, in agreement with those -K calculations by Neils Bohr 100 years ago. Problem solved!

Data-dependence Profiling to Enable Safe Thread Level Speculation

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

Bhattacharyya, Arnamoy; Amaral, José Nelson; Finkel, Hal

Data-dependence profling is a technique that enables a com- piler to judiciously decide when the execution of a loop | which the compiler could not prove to be dependence free | should be speculated through the use of Thread Level Spec- ulation (TLS). The data collected by a data-dependence pro- fler can be used to predict if may dependencies reported by a compiler static analysis are likely to materialize at runtime. A cost analysis can then be used to decide that some loops with a lower probability of dependence should be specula- tively parallelized. This paper addresses the question asmore » to whether a loops' dependence behaviour changes when the in- put to the program changes | a study of 57 different bench- marks indicates that it usually does not change. Then the paper describes SpecEval, an automatic speculative paral- lelization framework that uses single-input data-dependence profles to find speculation candidates in the SPEC2006 and PolyBench/C benchmarks. This paper also presents a per- formance evaluation of TLS implementation in IBM's Blue- Gene/Q supercomputer and shows that the performance of TLS is affected by several factors, including the number of speculated loops, the execution-time coverage of speculated loops, the miss-speculation overhead, the L1 cache miss rate and the effect on dynamic instruction path length.« less

Interface control of bulk ferroelectric polarization

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

Yu, P; Luo, Weidong; Yi, D.

2012-01-01

The control of material interfaces at the atomic level has led to no- vel interfacial properties and functionalities. In particular, the study of polar discontinuities at interfaces between complex oxides lies at the frontier of modern condensed matter research. Here we em- ploy a combination of experimental measurements and theoretical calculations to demonstrate the control of a bulk property, namely ferroelectric polarization, of a heteroepitaxial bilayer by precise atomic-scale interface engineering. More specifically, the control is achieved by exploiting the interfacial valence mismatch to influence the electrostatic potential step across the interface, which manifests itself as the biased-voltage in ferroelectricmore » hysteresis loops and determines the ferroelectric state. A broad study of diverse systems comprising different ferroelectrics and conducting perovskite un- derlayers extends the generality of this phenomenon.« less

Cambium

NASA Technical Reports Server (NTRS)

Savidge, Rodney

2009-01-01

The Cambium investigation is one in a pair of investigations which utilizes the Advanced Biological Research System (ABRS). Cambium seeks definitive evidence that gravity has a direct effect on cambial cells (cells located under the inner bark where secondary growth occurs) in willow, Salix babylonica. The Cambium investigation uses willow plants flown on the International Space Station to better understand the fundamental processes by which plants produce cellulose and lignin, the two main structural materials found in plant matter. On Earth, the nature of wood within tree stems varies depending on position, and that within-tree variation includes differences in cell types and chemistry including lignin and cellulose, two major components of wood influencing wood strength, usefulness and carbon content. Reaction wood is an extreme example of such variation, and it is believed that reaction wood develops as a reaction to the influence of gravity. For the Cambium experiment, young willow plants will be launched to the ISS where their stems will be looped in an attempt to induce reaction wood formation. After on-orbit growth, the plants will be preserved and returned to Earth for analysis. Understanding the role of gravity in wood formation is expected to enable wiser management of forests for carbon sequestration as well as better utilization of trees for wood products. Detailed Research Description: The Cambium experiment will provide an understanding of physiological processes such as gene expression, metabolism and general plant development that are affected in plant systems exposed to space flight. Cambium seeks definitive evidence that gravity has a direct effect on the cambial cells (cells located under the inner bark where secondary growth occurs) that contribute to xylogenesis (reaction wood formation) in willow plants, Salix babylonica. Tension wood fibers differentiate on the upper sides of stems when the stem is altered from its normal (vertical) growth position by looping. This reaction wood response does not occur if the orientation of the plant stem with respect to gravity is not altered. If a localized zone of tension wood should be formed in looped stems under microgravity conditions, this would be the first conclusive evidence that gravity is not required. On the other hand, if a zone of tension wood is not produced in looped stems (subjected to tension on one side, compression on the other) in microgravity, this would be the first definitive evidence that gravity has a direct effect on the cambial cells which contribute to reaction wood formation. Following return to Earth the plants will be analyzed by microscopy and chemical methods.

An Environment for Hardware-in-the-Loop Formation Navigation and Control Simulation

NASA Technical Reports Server (NTRS)

Burns, Rich

2004-01-01

Recent interest in formation flying satellite systems has spurred a considerable amount of research in the relative navigation and control of satellites. Development in this area has included new estimation and control algorithms as well as sensor and actuator development specifically geared toward the relative control problem. This paper describes a simulation facility, the Formation Flying Testbed (FFTB) at NASA's Goddard Space Flight Center, which allows engineers to test new algorithms for the formation flying problem with relevant GN&C hardware in a closed loop simulation. The FFTB currently supports the injection of GPS receiver hardware into the simulation loop, and support for satellite crosslink ranging technology is at a prototype stage. This closed-loop, hardware inclusive simulation capability permits testing of navigation and control software in the presence of the actual hardware with which the algorithms must interact. This capability provides the navigation or control developer with a perspective on how the algorithms perform as part of the closed-loop system. In this paper, the overall design and evolution of the FFTB are presented. Each component of the FFTB is then described in detail. Interfaces between the components of the FFTB are shown and the interfaces to and between navigation and control software are described in detail. Finally, an example of closed-loop formation control with GPS receivers in the loop is presented and results are analyzed.

Cardiac Dysfunction, Congestion and Loop Diuretics: their Relationship to Prognosis in Heart Failure.

PubMed

Pellicori, Pierpaolo; Cleland, John G F; Zhang, Jufen; Kallvikbacka-Bennett, Anna; Urbinati, Alessia; Shah, Parin; Kazmi, Syed; Clark, Andrew L

2016-12-01

Diuretics are the mainstay of treatment for congestion but concerns exist that they adversely affect prognosis. We explored whether the relationship between loop diuretic use and outcome is explained by the underlying severity of congestion amongst patients referred with suspected heart failure. Of 1190 patients, 712 had a left ventricular ejection fraction (LVEF) ≤50 %, 267 had LVEF >50 % with raised plasma NTproBNP (>400 ng/L) and 211 had LVEF >50 % with NTproBNP ≤400 ng/L; respectively, 72 %, 68 % and 37 % of these groups were treated with loop diuretics including 28 %, 29 % and 10 % in doses ≥80 mg furosemide equivalent/day. Compared to patients with cardiac dysfunction (either LVEF ≤50 % or NT-proBNP >400 ng/L) but not taking a loop diuretic, those taking a loop diuretic were older and had more clinical evidence of congestion, renal dysfunction, anaemia and hyponatraemia. During a median follow-up of 934 (IQR: 513-1425) days, 450 patients were hospitalized for HF or died. Patients prescribed loop diuretics had a worse outcome. However, in multi-variable models, clinical, echocardiographic (inferior vena cava diameter), and biochemical (NTproBNP) measures of congestion were strongly associated with an adverse outcome but not the use, or dose, of loop diuretics. Prescription of loop diuretics identifies patients with more advanced features of heart failure and congestion, which may account for their worse prognosis. Further research is needed to clarify the relationship between loop diuretic agents and outcome; imaging and biochemical measures of congestion might be better guides to diuretic dose than symptoms or clinical signs.

Coexistence of ΘI I-loop-current order with checkerboard d -wave CDW/PDW order in a hot-spot model for cuprate superconductors

NASA Astrophysics Data System (ADS)

de Carvalho, Vanuildo S.; Pépin, Catherine; Freire, Hermann

2016-03-01

We investigate the strong influence of the ΘI I-loop-current order on both unidirectional and bidirectional d -wave charge-density-wave/pair-density-wave (CDW/PDW) composite orders along axial momenta (±Q0,0 ) and (0 ,±Q0) that emerge in an effective hot-spot model departing from the three-band Emery model relevant to the phenomenology of the cuprate superconductors. This study is motivated by the compelling evidence that the ΘI I-loop-current order described by this model may explain groundbreaking experiments such as spin-polarized neutron scattering performed in these materials. Here, we demonstrate, within a saddle-point approximation, that the ΘI I-loop-current order clearly coexists with bidirectional (i.e., checkerboard) d -wave CDW and PDW orders along axial momenta, but is visibly detrimental to the unidirectional (i.e., stripe) case. This result has potentially far-reaching implications for the physics of the cuprates and agrees well with very recent x-ray experiments on YBCO that indicate that at higher dopings the CDW order has indeed a tendency to be bidirectional.

Closed-Loop Control System for Friction Stir Welding Retractable Pin Tool

NASA Technical Reports Server (NTRS)

Ding, R. Jeffrey; Romine, Peter L.; Munafo, Paul M. (Technical Monitor)

2001-01-01

NASA invention disclosure, NASA Case No. MFS-31413, entitled "System for Controlling the Stirring Pin of a Friction Stir Welding Apparatus", (Patent Pending) authored by Jeff Ding, Dr Peter Romine and Pete Oelgoetz, addresses the precision control of the friction stir welding process. The closed-loop control system automatically adjusts the spinning welding pin, real-time, to maintain a precise penetration ligament (i.e., distance between pin-tip and weld panel backside surface). A specific pin length can be maintained while welding constant thickness or tapered material thickness weld panels. The closed-loop control system provides operator data and information relative to the exact position of the welding pin inside the weld joint. This paper presents the closed-loop RPT control system that operates using the auto-feedback of force signals sensed by the tip and shoulder of the welding pin. Significance: The FSW process can be successfully used in a production environment only if there is a method or technique that informs the FSW operator the precise location of the welding pin inside the weld joint. This is essential for applications in aerospace, automotive, pressure vessel, commercial aircraft and other industries.

Ortho stops marketing Lippes Loop; cites economic factors.

PubMed

1985-11-01

Ortho Pharmaceutical Corporation has stopped marketing the Lippes Loop IUD, the only inert IUD currently available in the US. The firm cited "economic considerations" as its reason. Linda Organ, company spokeswoman, told Contraceptive Technology Update (CTU) that the number of women using IUDs has declined in the past few years and, as a result, Ortho's Lippes Loop sales dropped. Most physicians, according to Organ, currently prescribe copper-bearing IUDs. Few devices have been studied as thoroughly before marketing as the Lippes Loop, according to its developer, Dr. Jack Lippes. Lippes told CTU that the Population Council analyzed 40,000 women from 1962 to 1968 and "found no trouble with the Loop." Lippes attributes Ortho's recent decision to 2 factors: the IUD has been only "marginally profitable" and the problems of A.H. Robins with the Dalkon Shield has most likely had an effect; and the US Food and Drug Administration (FDA) published a proposed rule in August 1985 that would require any company wanting to manufacture and market IUDs like the Lippes Loop to submit a premarketing approval application to that agency. In effect, the FDA's rule would only apply to the Lippes Loop. Under the proposed rule, any company wanting to market Lippes Loops, or any nondrug IUD, would have to submit an application to the FDA with a detailed discussion and supporting clinical studies addressing the following concerns: pelvic actinomycosis; tubal infertility; duration that the IUD should remain in situ; and safety of leaving the IUD in situ when contraception is no longer indicated. According to Lillian Yin, FDA device evaluation, the clinical effectiveness and most of the safety issues regarding inert IUDs have been thoroughly covered in published data. She told CTU that "most of the information needed is straightforward, but the part that's new involves the long term use infection rate." Yin indicated that the FDA received a letter from Ortho advising the agency of the company's decision to discontinue selling the loop. That decision, according to Organ, is not based on new study information about inert versus copper bearing IUDs. The company sent a letter to physicians on April 15 advising them of revisions in Lippes Loop patient and physician information materials. The added information is cited.

Temporary Urine and Brine Stowage System (TUBSS) Materials Selection and Testing

NASA Technical Reports Server (NTRS)

Carrigan, Caitlin; Dries, Kevin; Pensinger, Stuart

2011-01-01

Storing wastewater in the event of a system anomaly is a necessity for closed loop water recovery systems. The temporary urine and brine stowage system (TUBSS) is an assembly used to store and transfer pre-treated urine (PTU) and brine for processing or disposal at a later date. This paper describes the selection and testing of several candidate materials from both a chemical and material strength standpoint. In addition, this paper will provide results of testing as well as lessons learned from the project, culminating in the successful launch of the hardware.

Sexuality Resource Guide and Supplement.

ERIC Educational Resources Information Center

Colorado State Library, Denver.

Intended for those working with the developmentally disabled, the bibliography contains approximately 300 entries on resource materials in the area of human sexuality. Included, with pertinent bibliographic information and a brief description, are listings of books, pamphlets, films, filmstrips, sound filmstrips, film loops, cassettes, articles,…

ION EXCHANGE SOFTENING: EFFECTS ON METAL CONCENTRATIONS

EPA Science Inventory

A corrosion control pipe loop study to evaluate the effect of ion exchange water softening on metal leaching from household plumbing materials was conducted on two different water qualities having different pH's and hardness levels. The results showed that removing hardness ions ...

Air Tight: Building Inflatables/Inflatable Construction: Planning and Details

NASA Technical Reports Server (NTRS)

Kennedy, Kriss J.

2016-01-01

A design-build seminar consisting of students from Physics, Mechanical and Civil Engineering, Robotic, Material Science, Art, and Architecture who will work together on a deployable "closed-loop" inflatable greenhouse for Mars in theory, and an Earth analogue physical mockup on campus.

Process Instrumentation. Teacher Edition.

ERIC Educational Resources Information Center

Brown, A. O., III; Fowler, Malcolm

This module provides instructional materials that are designed to help teachers train students in job skills for entry-level jobs as instrumentation technicians. This text addresses the basics of troubleshooting control loops, and the transducers, transmitters, signal conditioners, control valves, and controllers that enable process systems to…

Determination of Reaction Stoichiometries by Flow Injection Analysis.

ERIC Educational Resources Information Center

Rios, Angel; And Others

1986-01-01

Describes a method of flow injection analysis intended for calculation of complex-formation and redox reaction stoichiometries based on a closed-loop configuration. The technique is suitable for use in undergraduate laboratories. Information is provided for equipment, materials, procedures, and sample results. (JM)

Improved Frame Mode Selection for AMR-WB+ Based on Decision Tree

NASA Astrophysics Data System (ADS)

Kim, Jong Kyu; Kim, Nam Soo

In this letter, we propose a coding mode selection method for the AMR-WB+ audio coder based on a decision tree. In order to reduce computation while maintaining good performance, decision tree classifier is adopted with the closed loop mode selection results as the target classification labels. The size of the decision tree is controlled by pruning, so the proposed method does not increase the memory requirement significantly. Through an evaluation test on a database covering both speech and music materials, the proposed method is found to achieve a much better mode selection accuracy compared with the open loop mode selection module in the AMR-WB+.

Development of a contact heat exchanger for a constructable radiator system

NASA Technical Reports Server (NTRS)

Howell, H. R.

1983-01-01

A development program for a contact heat exchanger to be used to transfer heat from a spacecraft coolant loop to a heat pipe radiator is described. The contact heat exchanger provides for a connectable/disconnectable joint which allows for on-orbit assembly of the radiator system and replacement or exchange of radiator panels for repair and maintenance. The contact heat exchanger does not require the transfer of fluid across the joint; the spacecraft coolant loop remains contained in an all welded system with no static or dynamic fluid seals. The contact interface is also "dry' with no conductive grease or interstitial material required.

Open-loop characteristics of magnetic suspension systems using electromagnets mounted in a planar array

NASA Technical Reports Server (NTRS)

Groom, Nelson J.; Britcher, Colin P.

1992-01-01

The open-loop characteristics of a Large-Gap Magnetic Suspension System (LGMSS) were studied and numerical results are presented. The LGMSS considered provides five-degree-of-freedom control. The suspended element is a cylinder that contains a core composed of permanent magnet material. The magnetic actuators are air core electromagnets mounted in a planar array. Configurations utilizing five, six, seven, and eight electromagnets were investigated and all configurations were found to be controllable from coil currents and observable from suspended element positions. Results indicate that increasing the number of coils has an insignificant effect on mode shapes and frequencies.

Active Blade Vibration Control Being Developed and Tested

NASA Technical Reports Server (NTRS)

Johnson, Dexter

2003-01-01

Gas turbine engines are currently being designed to have increased performance, lower weight and manufacturing costs, and higher reliability. Consequently, turbomachinery components, such as turbine and compressor blades, have designs that are susceptible to new vibration problems and eventual in-service failure due to high-cycle fatigue. To address this problem, researchers at the NASA Glenn Research Center are developing and testing innovative active blade vibration control concepts. Preliminary results of using an active blade vibration control system, involving a rotor supported by an active magnetic bearing in Glenn's Dynamic Spin Rig, indicate promising results (see the photograph). Active blade vibration control was achieved using feedback of blade strain gauge signals within the magnetic bearing control loop. The vibration amplitude was reduced substantially (see the graphs). Also, vibration amplitude amplification was demonstrated; this could be used to enhance structural mode identification, if desired. These results were for a nonrotating two-bladed disk. Tests for rotating blades are planned. Current and future active blade vibration control research is planned to use a fully magnetically suspended rotor and smart materials. For the fully magnetically suspended rotor work, three magnetic bearings (two radial and one axial) will be used as actuators instead of one magnetic bearing. This will allow additional degrees of freedom to be used for control. For the smart materials work, control effectors located on and off the blade will be considered. Piezoelectric materials will be considered for on-the-blade actuation, and actuator placement on a stator vane, or other nearby structure, will be investigated for off-the-blade actuation. Initial work will focus on determining the feasibility of these methods by performing basic analysis and simple experiments involving feedback control.

Molten Chloride Salts for Heat Transfer in Nuclear Systems

NASA Astrophysics Data System (ADS)

Ambrosek, James Wallace

2011-12-01

A forced convection loop was designed and constructed to examine the thermal-hydraulic performance of molten KCl-MgCl2 (68-32 at %) salt for use in nuclear co-generation facilities. As part of this research, methods for prediction of the thermo-physical properties of salt mixtures for selection of the coolant salt were studied. In addition, corrosion studies of 10 different alloys were exposed to the KCl-MgCl2 to determine a suitable construction material for the loop. Using experimental data found in literature for unary and binary salt systems, models were found, or developed to extrapolate the available experimental data to unstudied salt systems. These property models were then used to investigate the thermo-physical properties of the LINO3-NaNO3-KNO 3-Ca(NO3), system used in solar energy applications. Using these models, the density, viscosity, adiabatic compressibility, thermal conductivity, heat capacity, and melting temperatures of higher order systems can be approximated. These models may be applied to other molten salt systems. Coupons of 10 different alloys were exposed to the chloride salt for 100 hours at 850°C was undertaken to help determine with which alloy to construct the loop. Of the alloys exposed, Haynes 230 had the least amount of weight loss per area. Nickel and Hastelloy N performed best based on maximum depth of attack. Inconel 625 and 718 had a nearly uniform depletion of Cr from the surface of the sample. All other alloys tested had depletion of Cr along the grain boundaries. The Nb in Inconel 625 and 718 changed the way the Cr is depleted in these alloys. Grain-boundary engineering (GBE) of Incoloy 800H improved the corrosion resistance (weight loss and maximum depth of attack) by nearly 50% as compared to the as-received Incoloy 800H sample. A high temperature pump, thermal flow meter, and pressure differential device was designed, constructed and tested for use in the loop, The heat transfer of the molten chloride salt was found to follow general correlations used to estimate the Nusselt number for water in both the forced convection laminar regime and in the mixed convection regime.

SEMICIRCULAR-LIKE SECONDARY FLARE RIBBONS ASSOCIATED WITH A FAILED ERUPTION

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

Zheng, R.; Korsós, M. B.; Erdélyi, R., E-mail: r.zheng@sheffield.ac.uk, E-mail: robertus@sheffield.ac.uk

Flare ribbons (FRs) are one of the most apparent signatures of solar flares and have been treated as an indicator of magnetic reconnection. Drawing upon the observations from the Solar Dynamics Observatory, we present semicircular-like secondary FRs (SFRs) of a C2.3 flare on 2013 June 19. Before the flare eruption, two bipoles in this core region subsequently emerged. Due to the interaction between the two bipoles, a tether-cutting eruption took place in the core region. The SFRs, surrounding the core region nearly simultaneously with the flare onset, were much weaker than the two normal FRs. Two ends of the SFRsmore » experienced a separation and extension movement, but the middle part of the SFRs hardly expanded outward. We find SFRs are closely associated with the footpoint brightenings of some small loops around the core region. The eruption was confined by transequatorial loops (TLs), which resulted in the plasma material falling in the north end of the TLs and remote brightenings showing up in the south end of the TLs. The disappearance of the faint (filament) material during the emergence of the SFRs could indicate another eruption. We conclude that two or more magnetic reconnections are involved in this event and propose that SFRs consisting of a small part of true FRs resulted from the second magnetic reconnection and bright footpoints of loop clusters likely heated by the main flare.« less

TEM in situ cube-corner indentation analysis using ViBe motion detection algorithm

NASA Astrophysics Data System (ADS)

Yano, K. H.; Thomas, S.; Swenson, M. J.; Lu, Y.; Wharry, J. P.

2018-04-01

Transmission electron microscopic (TEM) in situ mechanical testing is a promising method for understanding plasticity in shallow ion irradiated layers and other volume-limited materials. One of the simplest TEM in situ experiments is cube-corner indentation of a lamella, but the subsequent analysis and interpretation of the experiment is challenging, especially in engineering materials with complex microstructures. In this work, we: (a) develop MicroViBE, a motion detection and background subtraction-based post-processing approach, and (b) demonstrate the ability of MicroViBe, in combination with post-mortem TEM imaging, to carry out an unbiased qualitative interpretation of TEM indentation videos. We focus this work around a Fe-9%Cr oxide dispersion strengthened (ODS) alloy, irradiated with Fe2+ ions to 3 dpa at 500 °C. MicroViBe identifies changes in Laue contrast that are induced by the indentation; these changes accumulate throughout the mechanical loading to generate a "heatmap" of features in the original TEM video that change the most during the loading. Dislocation loops with b = ½ <111> identified by post-mortem scanning TEM (STEM) imaging correspond to hotspots on the heatmap, whereas positions of dislocation loops with b = <100> do not correspond to hotspots. Further, MicroViBe enables consistent, objective quantitative approximation of the b = ½ <111> dislocation loop number density.

Design and simulation of a sensor for heliostat field closed loop control

NASA Astrophysics Data System (ADS)

Collins, Mike; Potter, Daniel; Burton, Alex

2017-06-01

Significant research has been completed in pursuit of capital cost reductions for heliostats [1],[2]. The camera array closed loop control concept has potential to radically alter the way heliostats are controlled and installed by replacing high quality open loop targeting systems with low quality targeting devices that rely on measurement of image position to remove tracking errors during operation. Although the system could be used for any heliostat size, the system significantly benefits small heliostats by reducing actuation costs, enabling large numbers of heliostats to be calibrated simultaneously, and enabling calibration of heliostats that produce low irradiance (similar or less than ambient light images) on Lambertian calibration targets, such as small heliostats that are far from the tower. A simulation method for the camera array has been designed and verified experimentally. The simulation tool demonstrates that closed loop calibration or control is possible using this device.

Investigating the feasibility of a reuse scenario for textile fibres recovered from end-of-life tyres.

PubMed

Landi, Daniele; Gigli, Silvia; Germani, Michele; Marconi, Marco

2018-05-01

The management of end-of-life tyres (ELTs) is regulated by several national and international legislations aiming to promote the recovery of materials and energy from this waste. The three main materials used in tyres are considered: rubber (main product), which is currently reused in other closed-loop applications; steel, which is used for the production of virgin materials; and textile fibres (approximately 10% by weight of ELTs), which are mainly incinerated for energy recovery (open-loop scenario). This study aims to propose and validate a new closed-loop scenario for textile fibres based on material reuse for bituminous conglomerates. The final objective is to verify the technical, environmental, financial, and economic feasibility of the proposed treatment process and reuse scenario. After characterization of the textile material, which is required to determine the technological feasibility, a specific process has been developed to clean, compact, and prepare the fibres for subsequent reuse. A life cycle assessment (LCA) has been carried out to quantify the environmental benefits of reusing the fibres. Finally, a cost benefit analysis based on the LCA results was conducted to establish the long-term financial and economic sustainability. From a technological point of view, the tyre textile fibres could be a promising substitute to the reinforcement cellulose commonly used in asphalts as long as the fibres are properly prepared (compaction and pellet production) for application in the standard bituminous conglomerate production process. From an environmental point of view, relevant benefits in terms of global warming potential and acidification potential reduction were observed in comparison with the standard incineration for energy recovery (respectively -86% and -45%). Moreover, the proposed scenario can be considered as financially viable in the medium to long term (cumulative generated cash flow is positive after the 5th year) and economically sustainable (expected net present value of more than €3,000,000 and economic rate of return of approximately 30%). Finally, the sensitivity and risk analyses show that no specific issues are foreseen for the future implementation in real industrial applications. Copyright © 2018 Elsevier Ltd. All rights reserved.

Solid-State Nuclear Power

NASA Technical Reports Server (NTRS)

George, Jeffrey A.

2012-01-01

A strategy for "Solid-State" Nuclear Power is proposed to guide development of technologies and systems into the second 50 years of nuclear spaceflight. The strategy emphasizes a simple and highly integrated system architecture with few moving parts or fluid loops; the leverage of modern advances in materials, manufacturing, semiconductors, microelectromechanical and nanotechnology devices; and the targeted advancement of high temperature nuclear fuels, materials and static power conversion to enable high performance from simple system topologies.

PubMed Central

Worrall, Graham; Chambers, Larry W.

1990-01-01

With the increasing expenditure on health care programs for seniors, there is an urgent need to evaluate such programs. The Measurement Iterative Loop is a tool that can provide both health administrators and health researchers with a method of evaluation of existing programs and identification of gaps in knowledge, and forms a rational basis for health-care policy decisions. In this article, the Loop is applied to one common problem of the elderly: dementia. PMID:21233998

Solid State Research

DTIC Science & Technology

1985-08-15

Hz. The high-speed performance is consis- tent with the low stage delay observed in the ring-oscillator measurements , and the low - frequency ...Phase-Locked Loop 41 5-10 Phase-Locked-Loop Output Spectrum . Note that a 10-kHz Measure - ment Bandwidth Is Used. 42 5-11 Phase Error Response to an...the niobium. Reflections of bulk acoustic waves from optically generated holograms in Fe-doped LiNb03 have been observed and measured . Holographic

Gastric Injury From Oral Iron Supplementation

DTIC Science & Technology

2018-02-22

1100 Willford Hall Loop , Bldg 4430 JBSA-Lackland, TX 78236-9908 17540 210-292-7141 9. SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES) 10...SPONSOR/MONITOR"S ACRONYM(S) 59th Clinical Research Division 1100 Willford Hall Loop , Bldg 4430 JBSA-Lackland, TX 78236-9908 11. SPONSOR/MONITOR’S REPORT...follow up EGO that showed multiple new linear hyper -pigmented peripyloric extensions of unknown etiology. Tissue biopsy revealed pigmented foreign

The Functional Effect of an Amphiregulin Autocrine Loop on Inflammatory Breast Cancer Progression

DTIC Science & Technology

2007-03-01

autocrine loop exists in pancreatic cancer, colon cancer, and hepatocellular carcinoma (27-29). AR expression was also found to be strongly correlated...J, Erroba, E, Perugorria, MJ, et al. Amphiregulin contributes to the transformed phenotype of human hepatocellular carcinoma cells. Cancer Res... hepatocellular carcinoma (27–29). AR expression was also found to be * This research was supported by National Institutes of Health Grants R01

Closed-Loop and Robust Control of Quantum Systems

PubMed Central

Wang, Lin-Cheng

2013-01-01

For most practical quantum control systems, it is important and difficult to attain robustness and reliability due to unavoidable uncertainties in the system dynamics or models. Three kinds of typical approaches (e.g., closed-loop learning control, feedback control, and robust control) have been proved to be effective to solve these problems. This work presents a self-contained survey on the closed-loop and robust control of quantum systems, as well as a brief introduction to a selection of basic theories and methods in this research area, to provide interested readers with a general idea for further studies. In the area of closed-loop learning control of quantum systems, we survey and introduce such learning control methods as gradient-based methods, genetic algorithms (GA), and reinforcement learning (RL) methods from a unified point of view of exploring the quantum control landscapes. For the feedback control approach, the paper surveys three control strategies including Lyapunov control, measurement-based control, and coherent-feedback control. Then such topics in the field of quantum robust control as H ∞ control, sliding mode control, quantum risk-sensitive control, and quantum ensemble control are reviewed. The paper concludes with a perspective of future research directions that are likely to attract more attention. PMID:23997680

Insulin delivery and nocturnal glucose control in children and adolescents with type 1 diabetes.

PubMed

Tauschmann, Martin; Hovorka, Roman

2017-12-01

Nocturnal glucose control remains challenging in children and adolescents with type 1 diabetes due to highly variable overnight insulin requirements. The issue may be addressed by glucose responsive insulin delivery based on real-time continuous glucose measurements. Areas covered: This review outlines recent developments of glucose responsive insulin delivery systems from a paediatric perspective. We cover threshold-based suspend application, predictive low glucose suspend, and more advanced single hormone and dual-hormone closed-loop systems. Approaches are evaluated in relation to nocturnal glucose control particularly during outpatient randomised controlled trials. Expert opinion: Significant progress translating research from controlled clinical centre settings to free-living unsupervised home studies have been achieved over the past decade. Nocturnal glycaemic control can be improved whilst reducing the risk of hypoglycaemia with closed-loop systems. Following the US regulatory approval of the first hybrid closed-loop system in non-paediatric population, large multinational closed-loop clinical trials and pivotal studies including paediatric populations are underway or in preparation to facilitate the use of closed-loop systems in clinical practice.

Tornado-Like Evolution of A Kink-Unstable Solar Prominence

NASA Astrophysics Data System (ADS)

Wang, W.; Liu, R.; Wang, Y.

2016-12-01

We report on the tornado-like evolution of a quiescent prominence on 2014 November 1. The evolution started with a slow rise of the eastern section of the prominence into an arch-shaped structure as high as 150 Mm above the limb, and then the arch experienced a moderate, left-handed writhing. Following the writhing, the originally dark prominence material became in emission in the Fe IX 171 °A passband, and a braiding structure appeared at the eastern edge of the writhing prominence body, whose unraveling process was associated with a transient brightening in EUV and apparently contributed to the formation of a curtain-like structure (CLS), which consisted of myriads of thread-like loops rotating counterclockwise about the vertical if viewed from above. Material sliding along these loops landed outside of the prominence channel. The tornado was eventually disintegrated and the remaining material flew along a lefthanded helical path of approximately a full turn, as confirmed through stereoscopic reconstruction, into the cavity of the stable, western section of the prominence. We suggest that the tornado-like evolution of the prominence was regulated by the helical kink instability, and that the CLS forms through magnetic reconnections between the flux-rope flux and the overlying flux.

Nanoscale structural and functional mapping of nacre by scanning probe microscopy techniques

NASA Astrophysics Data System (ADS)

Zhou, Xilong; Miao, Hongchen; Li, Faxin

2013-11-01

Nacre has received great attention due to its nanoscale hierarchical structure and extraordinary mechanical properties. Meanwhile, the nanoscale piezoelectric properties of nacre have also been investigated but the structure-function relationship has never been addressed. In this work, firstly we realized quantitative nanomechanical mapping of nacre of a green abalone using atomic force acoustic microscopy (AFAM). The modulus of the mineral tablets is determined to be ~80 GPa and that of the organic biopolymer no more than 23 GPa, and the organic-inorganic interface width is determined to be about 34 +/- 9 nm. Then, we conducted both AFAM and piezoresponse force microscopy (PFM) mapping in the same scanning area to explore the correlations between the nanomechanical and piezoelectric properties. The PFM testing shows that the organic biopolymer exhibits a significantly stronger piezoresponse than the mineral tablets, and they permeate each other, which is very difficult to reproduce in artificial materials. Finally, the phase hysteresis loops and amplitude butterfly loops were also observed using switching spectroscopy PFM, implying that nacre may also be a bio-ferroelectric material. The obtained nanoscale structural and functional properties of nacre could be very helpful in understanding its deformation mechanism and designing biomimetic materials of extraordinary properties.

Tornado-like Evolution of a Kink-unstable Solar Prominence

NASA Astrophysics Data System (ADS)

Wang, Wensi; Liu, Rui; Wang, Yuming

2017-01-01

We report on the tornado-like evolution of a quiescent prominence on 2014 November 1. The eastern section of the prominence first rose slowly, transforming into an arch-shaped structure as high as ˜150 Mm above the limb; the arch then writhed moderately in a left-handed sense, while the original dark prominence material emitted in the Fe ix 171 Å passband, and a braided structure appeared at the eastern edge of the warped arch. The unraveling of the braided structure was associated with a transient brightening in the EUV and apparently contributed to the formation of a curtain-like structure (CLS). The CLS consisted of myriad thread-like loops rotating counterclockwise about the vertical if viewed from above. Heated prominence material was observed to slide along these loops and land outside the filament channel. The tornado eventually disintegrated and the remaining material flew along a left-handed helical path constituting approximately a full turn, as corroborated through stereoscopic reconstruction, into the cavity of the stable, western section of the prominence. We suggest that the tornado-like evolution of the prominence was governed by the helical kink instability, and that the CLS formed through magnetic reconnections between the prominence field and the overlying coronal field.

Kalman Orbit Optimized Loop Tracking

NASA Technical Reports Server (NTRS)

Young, Lawrence E.; Meehan, Thomas K.

2011-01-01

Under certain conditions of low signal power and/or high noise, there is insufficient signal to noise ratio (SNR) to close tracking loops with individual signals on orbiting Global Navigation Satellite System (GNSS) receivers. In addition, the processing power available from flight computers is not great enough to implement a conventional ultra-tight coupling tracking loop. This work provides a method to track GNSS signals at very low SNR without the penalty of requiring very high processor throughput to calculate the loop parameters. The Kalman Orbit-Optimized Loop (KOOL) tracking approach constitutes a filter with a dynamic model and using the aggregate of information from all tracked GNSS signals to close the tracking loop for each signal. For applications where there is not a good dynamic model, such as very low orbits where atmospheric drag models may not be adequate to achieve the required accuracy, aiding from an IMU (inertial measurement unit) or other sensor will be added. The KOOL approach is based on research JPL has done to allow signal recovery from weak and scintillating signals observed during the use of GPS signals for limb sounding of the Earth s atmosphere. That approach uses the onboard PVT (position, velocity, time) solution to generate predictions for the range, range rate, and acceleration of the low-SNR signal. The low- SNR signal data are captured by a directed open loop. KOOL builds on the previous open loop tracking by including feedback and observable generation from the weak-signal channels so that the MSR receiver will continue to track and provide PVT, range, and Doppler data, even when all channels have low SNR.

PREFACE: Loops 11: Non-Perturbative / Background Independent Quantum Gravity

NASA Astrophysics Data System (ADS)

Mena Marugán, Guillermo A.; Barbero G, J. Fernando; Garay, Luis J.; Villaseñor, Eduardo J. S.; Olmedo, Javier

2012-05-01

Loops 11 The international conference LOOPS'11 took place in Madrid from the 23-28 May 2011. It was hosted by the Instituto de Estructura de la Materia (IEM), which belongs to the Consejo Superior de Investigaciones Cientĺficas (CSIC). Like previous editions of the LOOPS meetings, it dealt with a wealth of state-of-the-art topics on Quantum Gravity, with special emphasis on non-perturbative background-independent approaches to spacetime quantization. The main topics addressed at the conference ranged from the foundations of Quantum Gravity to its phenomenological aspects. They encompassed different approaches to Loop Quantum Gravity and Cosmology, Polymer Quantization, Quantum Field Theory, Black Holes, and discrete approaches such as Dynamical Triangulations, amongst others. In addition, this edition celebrated the 25th anniversary of the introduction of the now well-known Ashtekar variables and the Wednesday morning session was devoted to this silver jubilee. The structure of the conference was designed to reflect the current state and future prospects of research on the different topics mentioned above. Plenary lectures that provided general background and the 'big picture' took place during the mornings, and the more specialised talks were distributed in parallel sessions during the evenings. To be more specific, Monday evening was devoted to Shape Dynamics and Phenomenology Derived from Quantum Gravity in Parallel Session A, and to Covariant Loop Quantum Gravity and Spin foams in Parallel Session B. Tuesday's three Parallel Sessions dealt with Black Hole Physics and Dynamical Triangulations (Session A), the continuation of Monday's session on Covariant Loop Quantum Gravity and Spin foams (Session B) and Foundations of Quantum Gravity (Session C). Finally, Thursday and Friday evenings were devoted to Loop Quantum Cosmology (Session A) and to Hamiltonian Loop Quantum Gravity (Session B). The result of the conference was very satisfactory and enlightening. Not only was it a showroom for the research currently being carried out by many groups throughout the world, but there was also a permanent look towards the future. During these days, the CSIC Campus witnessed many scientific conversations triggered by the interaction amongst the people and groups that participated in LOOPS'11 Madrid and which, in many cases, will crystallise into new results and advances in the field. The conference would not have been possible without the generous help of a number of national and international institutions. The organizers would like to acknowledge the financial support provided by the Spanish Ministry of Science and Innovation (Ministerio de Ciencia e Innovación), the Spanish Research Council, CSIC (Consejo Superior de Investigaciones Cientĺficas), The BBVA Foundation (Fundación BBVA), The CONSOLIDER-CPAN project, the Spanish Society for Gravitation and Relativity (SEGRE), The Universidad Carlos III of Madrid (UC3M), and the European Science Foundation (ESF). The ESF, through the Quantum Gravity and Quantum Geometry network, provided full support for a number of young participants that have contributed to these proceedings: Dario Benedetti (Albert Einstein Institute, Potsdam, Germany), Norbert Bodendorfer (Institute for Theoretical Physics III, FAU Erlangen Nürnberg, Germany), Mariam Bouhmadi López (CENTRA, Centro Multidisciplinar de Astrofĺsica, Lisbon), Timothy Budd (Institute for Theoretical Physics, Utrecht University, The Netherlands), Miguel Campiglia (Institute for Gravitation and the Cosmos, Penn State University, USA), Gianluca Delfino (School of Mathematical Sciences, University of Nottingham, UK), Maite Dupuis (Institute for Theoretical Physics III, FAU Erlangen Nürnberg, Germany), Michał Dziendzikowski (Institute of Theoretical Physics, Warsaw University, Poland), Muxin Han (Centre de Physique Théorique de Luminy, Marseille, France), Philipp Höhn (Institute for Theoretical Physics, Utrecht University, The Netherlands), Jacek Puchta (Centre de Physique Théorique de Luminy, Marseille, France), James Ryan (Albert Einstein Institute, Potsdam, Germany), Lorenzo Sindoni (Albert Einstein Institute, Golm, Germany), David Sloan (Institute for Theoretical Physics, Utrecht University, The Netherlands), Johannes Tambornino (Laboratoire de Physique, ENS Lyon, France), Andreas Thurn (Institute for Theoretical Physics III, FAU Erlangen Nürnberg, Germany), Francesca Vidotto (Laboratoire de Physique Subatomique et de Cosmologie, Grenoble, France), and Matteo Smerlak (Albert Einstein Institute, Golm, Germany). We would like to conclude this preamble by thanking all the attendants of the conference for their high and enthusiastic participation. The presence of a large number of past and present Loop Quantum Gravity practitioners, as well as a significant number of top researchers in other approaches to quantum gravity, provided ample opportunities for fruitful scientific exchanges and a very lively atmosphere. It is encouraging to see that, 25 years after the inception of Loop Quantum Gravity, there is a vibrant young community of researchers entering the field. Let us hope that, with their help, the quantization of general relativity can be successfully accomplished in the near future. The Editors Conference photograph

CSI computer system/remote interface unit acceptance test results

NASA Technical Reports Server (NTRS)

Sparks, Dean W., Jr.

1992-01-01

The validation tests conducted on the Control/Structures Interaction (CSI) Computer System (CCS)/Remote Interface Unit (RIU) is discussed. The CCS/RIU consists of a commercially available, Langley Research Center (LaRC) programmed, space flight qualified computer and a flight data acquisition and filtering computer, developed at LaRC. The tests were performed in the Space Structures Research Laboratory (SSRL) and included open loop excitation, closed loop control, safing, RIU digital filtering, and RIU stand alone testing with the CSI Evolutionary Model (CEM) Phase-0 testbed. The test results indicated that the CCS/RIU system is comparable to ground based systems in performing real-time control-structure experiments.

Tower reactors for bioconversion of lignocellulosic material

DOEpatents

Nguyen, Quang A.

1999-01-01

An apparatus for enzymatic hydrolysis and fermentation of pretreated lignocellulosic material, in the form of a tower bioreactor, having mixers to achieve intermittent mixing of the material. Precise mixing of the material is important for effective heat and mass transfer requirements without damaging or denaturing the enzymes or fermenting microorganisms. The pretreated material, generally in the form of a slurry, is pumped through the bioreactor, either upwards or downwards, and is mixed periodically as it passes through the mixing zones where the mixers are located. For a thin slurry, alternate mixing can be achieved by a pumping loop which also serves as a heat transfer device. Additional heat transfer takes place through the reactor heat transfer jackets.

Tower reactors for bioconversion of lignocellulosic material

DOEpatents

Nguyen, Quang A.

1998-01-01

An apparatus for enzymatic hydrolysis and fermentation of pretreated lignocellulosic material, in the form of a tower bioreactor, having mixers to achieve intermittent mixing of the material. Precise mixing of the material is important for effective heat and mass transfer requirements without damaging or denaturing the enzymes or fermenting microorganisms. The pretreated material, generally in the form of a slurry, is pumped through the bioreactor, either upwards of downwards, and is mixed periodically as it passes through the mixing zones where the mixers are located. For a thin slurry, alternate mixing can be achieved by a pumping loop which also serves as a heat transfer device. Additional heat transfer takes place through the reactor heat transfer jackets.

Pumped lithium loop test to evaluate advanced refractory metal alloys and simulated nuclear fuel elements

NASA Technical Reports Server (NTRS)

Brandenburf, G. P.; Hoffman, E. E.; Smith, J. P.

1974-01-01

The performance was determined of refractory metal alloys and uranium nitride fuel element specimens in flowing 1900F (1083C) lithium. The results demonstrate the suitability of the selected materials to perform satisfactorily from a chemical compatibility standpoint.

Long-Term Pavement Performance Materials Characterization Program: Verification of Dynamic Test Systems with an Emphasis on Resilient Modulus

DOT National Transportation Integrated Search

2005-09-01

This document describes a procedure for verifying a dynamic testing system (closed-loop servohydraulic). The procedure is divided into three general phases: (1) electronic system performance verification, (2) calibration check and overall system perf...

Techniques for Teachers Section

ERIC Educational Resources Information Center

Tait, A., Ed.

1973-01-01

Includes a simple technique to demonstrate Millikan's oil drop experiment, an environmental studies experiment to measure dissolved oxygen in water samples, and a technique to demonstrate action-reaction. Science materials described are the Pol-A-Star Tomiscope, Nuffield chemistry film loops, air pucks and pH meters. (JR)

Mitochondrial D-loop sequence of domesticated waterfowl in Central Java: goose and muscovy duck

NASA Astrophysics Data System (ADS)

Susanti, R.; Iswari, R. S.

2018-03-01

This study aims to determine the genetic characterization of domesticated waterfowl (goose and Muscovy duck) in Central Java based on a D-loop mtDNA gene. The D-loop gene was amplified using PCR technique by specific primer and sequenced using dideoxy termination method. Multiple alignments of D-loop gene obtained were 710 nucleotides at position 74 to 783 at the 5’ end (for goose) and 712 nucleotides at position 48 to 759 at the 5’ end (for Muscovy duck). The results of the polymorphism analysis on D-loop sequences of muscovy duck produced 3 haplotypes. In the D-loop gene of goose does not show polymorphism, with substitution at G117A. Phylogenetic trees reconstructions of goose and Muscovy duck, which was collected during this research compared with another species from Anser, Chairina and Anas was generated 2 forms of clusters. The first group consists of all kind of Muscovy duck together with Chairina moschata and Anas, while the second group consists of all geese and Anser cygnoides the other. The determination of Muscovy duck and geese identity can be distinguished from the genetic marker information. Based on the phylogenetic analysis, it can be concluded that the Muscovy duck is closely related to Chairina moschata, while geese is closely related to Anser cygnoides.

A digital wireless system for closed-loop inhibition of nociceptive signals

NASA Astrophysics Data System (ADS)

Zuo, Chao; Yang, Xiaofei; Wang, Yang; Hagains, Christopher E.; Li, Ai-Ling; Peng, Yuan B.; Chiao, J.-C.

2012-10-01

Neurostimulation of the spinal cord or brain has been used to inhibit nociceptive signals in pain management applications. Nevertheless, most of the current neurostimulation models are based on open-loop system designs. There is a lack of closed-loop systems for neurostimulation in research with small freely-moving animals and in future clinical applications. Based on our previously developed analog wireless system for closed-loop neurostimulation, a digital wireless system with real-time feedback between recorder and stimulator modules has been developed to achieve multi-channel communication. The wireless system includes a wearable recording module, a wearable stimulation module and a transceiver connected to a computer for real-time and off-line data processing, display and storage. To validate our system, wide dynamic range neurons in the spinal cord dorsal horn have been recorded from anesthetized rats in response to graded mechanical stimuli (brush, pressure and pinch) applied in the hind paw. The identified nociceptive signals were used to automatically trigger electrical stimulation at the periaqueductal gray in real time to inhibit their own activities by the closed-loop design. Our digital wireless closed-loop system has provided a simplified and efficient method for further study of pain processing in freely-moving animals and potential clinical application in patients. Groups 1, 2 and 3 contributed equally to this project.

Characteristics of Helical Flow through Neck Cutoffs

NASA Astrophysics Data System (ADS)

Richards, D.; Konsoer, K. M.; Turnipseed, C.; Willson, C. S.

2017-12-01

Meander cutoffs and oxbows lakes are a ubiquitous feature of riverine landscapes yet there is a paucity of detailed investigations concentrated on the three-dimensional flow structure through evolving neck cutoffs. The purpose of this research is to investigate and characterize helical flow through neck cutoffs with two different planform configurations: elongate meander loops and serpentine loops. Three-dimensional velocity measurements was collected with an acoustic Doppler current profiler for five cutoffs on the White River, Arkansas. Pronounced helical flow was found through all elongate loop cutoff sites, formed from the balance between centrifugal force resulting from the curving of flow through the cutoff channel and pressure gradient force resulting from water surface super-elevation between primary flow and flow at the entrance and exit of the abandoned loop. The sense of motion of the helical flow caused near-surface fluid to travel outward toward the abandoned loop while near-bed fluid was redirected toward the downstream channel. Another characteristic of the helical flow structure for elongate loop cutoffs was the reversal of helical flow over a relatively short distance, causing patterns of secondary circulation that differed from typical patterns observed through curved channels with point bars. Lastly, helical flow was revealed within zones of strong flow recirculation, enhanced by an exchange of streamwise momentum between shear layers.

Accidental degeneracy in k-space, geometrical phase, and the perturbation of π by spin-orbit interactions

NASA Astrophysics Data System (ADS)

Allen, Philip B.; Pickett, Warren E.

2018-06-01

Since closed lines of accidental electronic degeneracies were demonstrated to be possible, even frequent, by Herring in 1937, no further developments arose for eight decades. The earliest report of such a nodal loop in a real material - aluminum - is recounted and elaborated on. Nodal loop semimetals have become a focus of recent activity, with emphasis on other issues. Band degeneracies are, after all, the origin of topological phases in crystalline materials. Spin-orbit interaction lifts accidental band degeneracies, with the resulting spectrum being provided here. The geometric phase γ(C) = ± π for circuits C surrounding a line of such degeneracy cannot survive completely unchanged. The change depends on how the spin is fixed during adiabatic evolution. For spin fixed along the internal spin-orbit field, γ(C) decreases to zero as the circuit collapses around the line of lifted degeneracy. For spin fixed along a perpendicular axis, the conical intersection persists and γ(C) = ± π is unchanged.

Evaluation of Sorbents for Acetylene Separation in Atmosphere Revitalization Loop Closure

NASA Technical Reports Server (NTRS)

Abney, Morgan B.; Miller, Lee A.; Barton, Katherine

2012-01-01

State-of-the-art carbon dioxide reduction technology uses a Sabatier reactor to recover water from metabolic carbon dioxide. In order to maximize oxygen loop closure, a byproduct of the system, methane, must be reduced to recover hydrogen. NASA is currently exploring a microwave plasma methane pyrolysis system for this purpose. The resulting product stream of this technology includes unreacted methane, product hydrogen, and acetylene. The hydrogen and the small amount of unreacted methane resulting from the pyrolysis process can be returned to the Sabatier reactor thereby substantially improving the overall efficiency of the system. However, the acetylene is a waste product that must be removed from the pyrolysis product. Two materials have been identified as potential sorbents for acetylene removal: zeolite 4A, a commonly available commercial sorbent, and HKUST-1, a newly developed microporous metal. This paper provides an explanation of the rationale behind acetylene removal and the results of separation testing with both materials

Evaluation of Sorbents for Acetylene Separation in Atmosphere Revitalization Loop Closure

NASA Technical Reports Server (NTRS)

Abney, Morgan B.; Miller, Lee A.; Barton, Katherine

2011-01-01

State-of-the-art carbon dioxide reduction technology uses a Sabatier reactor to recover water from metabolic carbon dioxide. In order to maximize oxygen loop closure, a byproduct of the system, methane, must be reduced to recover hydrogen. NASA is currently exploring a microwave plasma methane pyrolysis system for this purpose. The resulting product stream of this technology includes unreacted methane, product hydrogen, and acetylene. The hydrogen and the small amount of unreacted methane resulting from the pyrolysis process can be returned to the Sabatier reactor thereby substantially improving the overall efficiency of the system. However, the acetylene is a waste product that must be removed from the pyrolysis product. Two materials have been identified as potential sorbents for acetylene removal: zeolite 4A, a commonly available commercial sorbent, and HKUST-1, a newly developed microporous metal. This paper provides an explanation of the rationale behind acetylene removal and the results of separation testing with both materials.

LANDFILLS AS BIOREACTORS: RESEARH AT THE OUTER LOOP LANDFILL, LOUISVILLE, KENTUCKY; FIRST INTERIM REPORT

EPA Science Inventory

Interim report resulting from a cooperative research and development agreement (CRADA) between US EP A's Officeof Research and Development - National Risk Management Research Laboratory and a n ongoing field demonstration
of municipal waste landfills being operated as bioreact...

An analytical and experimental study to investigate flutter suppression via piezoelectric actuation. M.S. Thesis - George Washington Univ., 1991

NASA Technical Reports Server (NTRS)

Heeg, Jennifer

1991-01-01

The objective was to analytically and experimentally study the capabilities of adaptive material plate actuators for suppressing flutter. The validity of analytical modeling techniques for piezoelectric materials was also investigated. Piezoelectrics are materials which are characterized by their ability to produce voltage when subjected to a mechanical strain. The converse piezoelectric effect can be utilized to actuate a structure by applying a voltage. For this investigation, a two degree of freedom wind tunnel model was designed, analyzed, and tested. The model consisted of a rigid airfoil and a flexible mount system which permitted a translational and a rotational degree of freedom. It was designed such that flutter was encounted within the testing envelope of the wind tunnel. Actuators, made of piezoelectric material were affixed to leaf springs of the mount system. Each degree of freedom was controlled by a separate leaf spring. Command signals, applied to the piezoelectric actuators, exerted control over the damping and stiffness properties. A mathematical aeroservoelastic model was constructed using finite element methods, laminated plate theory, and aeroelastic analysis tools. Plant characteristics were determined from this model and verified by open loop experimental tests. A flutter suppression control law was designed and implemented on a digital control computer. Closed loop flutter testing was conducted. The experimental results represent the first time that adaptive materials have been used to actively suppress flutter. It demonstrates that small, carefully placed actuating plates can be used effectively to control aeroelastic response.

Rational Design of Mixed-Metal Oxides for Chemical Looping Combustion of Coal via Coupled Computational-Experimental Studies

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

Mishra, Amit; Li, Fanxing; Santiso, Erik

Energy and global climate change are two grand challenges to the modern society. An urgent need exists for development of clean and efficient energy conversion processes. The chemical looping strategy, which utilizes regenerable oxygen carriers (OCs) to indirectly convert carbonaceous fuels via redox reactions, is considered to be one of the more promising approaches for CO2 capture by the U.S. Department of Energy (USDOE). To date, most long-term chemical looping operations were conducted using gaseous fuels, even though direct conversion of coal is more desirable from both economics and CO2 capture viewpoints. The main challenges for direct coal conversion residemore » in the stringent requirements on oxygen carrier performances. In addition, coal char and volatile compounds are more challenging to convert than gaseous fuels. A promising approach for direct conversion of coal is the so called chemical looping with oxygen uncoupling (CLOU) technique. In the CLOU process, a metal oxide that decomposes at the looping temperature, and releases oxygen to the gas phase is used as the OC. The overarching objective of this project was to discover the fundamental principles for rational design and optimization of oxygen carriers (OC) in coal chemical looping combustion (CLC) processes. It directly addresses Topic Area B of the funding opportunity announcement (FOA) in terms of “predictive description of the phase behavior and mechanical properties” of “mixed metal oxide” based OCs and rational development of new OC materials with superior functionality. This was achieved through studies exploring i) iron-containing mixed-oxide composites as oxygen carriers for CLOU, ii) Ca1-xAxMnO3-δ (A = Sr and Ba) as oxygen carriers for CLOU, iii) CaMn1-xBxO3-δ (B=Al, V, Fe, Co, and Ni) as oxygen carrier for CLOU and iv) vacancy creation energy in Mn-containing perovskites as an indicator chemical looping with oxygen uncoupling.« less

Numerical Simulation of DC Coronal Heating

NASA Astrophysics Data System (ADS)

Dahlburg, Russell B.; Einaudi, G.; Taylor, Brian D.; Ugarte-Urra, Ignacio; Warren, Harry; Rappazzo, A. F.; Velli, Marco

2016-05-01

Recent research on observational signatures of turbulent heating of a coronal loop will be discussed. The evolution of the loop is is studied by means of numerical simulations of the fully compressible three-dimensional magnetohydrodynamic equations using the HYPERION code. HYPERION calculates the full energy cycle involving footpoint convection, magnetic reconnection, nonlinear thermal conduction and optically thin radiation. The footpoints of the loop magnetic field are convected by random photospheric motions. As a consequence the magnetic field in the loop is energized and develops turbulent nonlinear dynamics characterized by the continuous formation and dissipation of field-aligned current sheets: energy is deposited at small scales where heating occurs. Dissipation is non-uniformly distributed so that only a fraction of thecoronal mass and volume gets heated at any time. Temperature and density are highly structured at scales which, in the solar corona, remain observationally unresolved: the plasma of the simulated loop is multi thermal, where highly dynamical hotter and cooler plasma strands are scattered throughout the loop at sub-observational scales. Typical simulated coronal loops are 50000 km length and have axial magnetic field intensities ranging from 0.01 to 0.04 Tesla. To connect these simulations to observations the computed number densities and temperatures are used to synthesize the intensities expected in emission lines typically observed with the Extreme ultraviolet Imaging Spectrometer (EIS) on Hinode. These intensities are then employed to compute differential emission measure distributions, which are found to be very similar to those derived from observations of solar active regions.

Observational Signatures of Coronal Heating

NASA Astrophysics Data System (ADS)

Dahlburg, R. B.; Einaudi, G.; Ugarte-Urra, I.; Warren, H. P.; Rappazzo, A. F.; Velli, M.; Taylor, B.

2016-12-01

Recent research on observational signatures of turbulent heating of a coronal loop will be discussed. The evolution of the loop is is studied by means of numericalsimulations of the fully compressible three-dimensionalmagnetohydrodynamic equations using the HYPERION code. HYPERION calculates the full energy cycle involving footpoint convection, magnetic reconnection,nonlinear thermal conduction and optically thin radiation.The footpoints of the loop magnetic field are convected by random photospheric motions. As a consequence the magnetic field in the loop is energized and develops turbulent nonlinear dynamics characterized by the continuous formation and dissipation of field-aligned current sheets: energy is deposited at small scales where heating occurs. Dissipation is non-uniformly distributed so that only a fraction of thecoronal mass and volume gets heated at any time. Temperature and density are highly structured at scales which, in the solar corona, remain observationally unresolved: the plasma of the simulated loop is multi-thermal, where highly dynamical hotter and cooler plasma strands arescattered throughout the loop at sub-observational scales. Typical simulated coronal loops are 50000 km length and have axial magnetic field intensities ranging from 0.01 to 0.04 Tesla.To connect these simulations to observations the computed numberdensities and temperatures are used to synthesize the intensities expected inemission lines typically observed with the Extreme ultraviolet Imaging Spectrometer(EIS) on Hinode. These intensities are then employed to compute differentialemission measure distributions, which are found to be very similar to those derivedfrom observations of solar active regions.

Current and Prospective Li-Ion Battery Recycling and Recovery Processes

NASA Astrophysics Data System (ADS)

Heelan, Joseph; Gratz, Eric; Zheng, Zhangfeng; Wang, Qiang; Chen, Mengyuan; Apelian, Diran; Wang, Yan

2016-10-01

The lithium ion (Li-ion) battery industry has been growing exponentially since its initial inception in the late 20th century. As battery materials evolve, the applications for Li-ion batteries have become even more diverse. To date, the main source of Li-ion battery use varies from consumer portable electronics to electric/hybrid electric vehicles. However, even with the continued rise of Li-ion battery development and commercialization, the recycling industry is lagging; approximately 95% of Li-ion batteries are landfilled instead of recycled upon reaching end of life. Industrialized recycling processes are limited and only capable of recovering secondary raw materials, not suitable for direct reuse in new batteries. Most technologies are also reliant on high concentrations of cobalt to be profitable, and intense battery sortation is necessary prior to processing. For this reason, it is critical that a new recycling process be commercialized that is capable of recovering more valuable materials at a higher efficiency. A new technology has been developed by the researchers at Worcester Polytechnic Institute which is capable of recovering LiNi x Mn y Co z O2 cathode material from a hydrometallurgical process, making the recycling system as a whole more economically viable. By implementing a flexible recycling system that is closed-loop, recycling of Li-ion batteries will become more prevalent saving millions of pounds of batteries from entering the waste stream each year.

Megawatt-Scale Power Hardware-in-the-Loop Simulation Testing of a Power Conversion Module for Naval Applications

DTIC Science & Technology

2015-06-21

problem was detected . Protection elements were implemented to trigger on over- voltage , over-current, over/under-frequency, and zero-sequence voltage ...power hardware in the loop simulation of distribution networks with photovoltaic generation,” International Journal of Renewable Energy Research...source modules were intended to support both emulation of a representative gas turbine generator set, as well as a flexible, controllable voltage source

Human-In-The-Loop Experimental Research for Detect and Avoid

NASA Technical Reports Server (NTRS)

Consiglio, Maria; Munoz, Cesar; Hagen, George; Narkawicz, Anthony; Upchurch, Jason; Comstock, James; Ghatas, Rania; Vincent, Michael; Chamberlain, James

2015-01-01

This paper describes a Detect and Avoid (DAA) concept for integration of UAS into the NAS developed by the National Aeronautics and Space Administration (NASA) and provides results from recent human-in-the-loop experiments performed to investigate interoperability and acceptability issues associated with these vehicles and operations. The series of experiments was designed to incrementally assess critical elements of the new concept and the enabling technologies that will be required.

Interplay between short-range correlated disorder and Coulomb interaction in nodal-line semimetals

NASA Astrophysics Data System (ADS)

Wang, Yuxuan; Nandkishore, Rahul M.

2017-09-01

In nodal-line semimetals, Coulomb interactions and short-range correlated disorder are both marginal perturbations to the clean noninteracting Hamiltonian. We analyze their interplay using a weak-coupling renormalization group approach. In the clean case, the Coulomb interaction has been found to be marginally irrelevant, leading to Fermi liquid behavior. We extend the analysis to incorporate the effects of disorder. The nodal line structure gives rise to kinematical constraints similar to that for a two-dimensional Fermi surface, which plays a crucial role in the one-loop renormalization of the disorder couplings. For a twofold degenerate nodal loop (Weyl loop), we show that disorder flows to strong coupling along a unique fixed trajectory in the space of symmetry inequivalent disorder couplings. Along this fixed trajectory, all symmetry inequivalent disorder strengths become equal. For a fourfold degenerate nodal loop (Dirac loop), disorder also flows to strong coupling, however, the strengths of symmetry inequivalent disorder couplings remain different. We show that feedback from disorder reverses the sign of the beta function for the Coulomb interaction, causing the Coulomb interaction to flow to strong coupling as well. However, the Coulomb interaction flows to strong coupling asymptotically more slowly than disorder. Extrapolating our results to strong coupling, we conjecture that at low energies nodal line semimetals should be described by a noninteracting nonlinear sigma model. We discuss the relation of our results with possible many-body localization at zero temperatures in such materials.

Regenerable Sorbent for CO2 Removal

NASA Technical Reports Server (NTRS)

Alptekin, Gokhan; Jayaraman, Ambal

2013-01-01

A durable, high-capacity regenerable sorbent can remove CO2 from the breathing loop under a Martian atmosphere. The system design allows near-ambient temperature operation, needs only a small temperature swing, and sorbent regeneration takes place at or above 8 torr, eliminating the potential for Martian atmosphere to leak into the regeneration bed and into the breathing loop. The physical adsorbent can be used in a metabolic, heat-driven TSA system to remove CO2 from the breathing loop of the astronaut and reject it to the Martian atmosphere. Two (or more) alternating sorbent beds continuously scrub and reject CO2 from the spacesuit ventilation loop. The sorbent beds are cycled, alternately absorbing CO2 from the vent loop and rejecting the adsorbed material into the environment at a high CO2 partial pressure (above 8 torr). The system does not need to run the adsorber at cryogenic temperatures, and uses a much smaller temperature swing. The sorbent removes CO2 via a weak chemical interaction. The interaction is strong enough to enable CO2 adsorption even at 3 to 7.6 torr. However, because the interaction between the surface adsorption sites and the CO2 is relatively weak, the heat input needed to regenerate the sorbent is much lower than that for chemical absorbents. The sorbent developed in this project could potentially find use in a large commercial market in the removal of CO2 emissions from coal-fired power plants, if regulations are put in place to curb carbon emissions from power plants.

2001 NRL Review

DTIC Science & Technology

2001-01-01

Air Force Research Laboratory , Rome Research Site ( AFRL /RSS) in Rome, New York. The... AFRL ). The Kinetic Kill Vehicle Hardware in the Loop Simulator (KHILS) is managed by the Air Force Research Laboratory Mu- nitions Directorate ( AFRL ...Development Department 2Spacecraft Engineering Department 3Optical Sciences Division 4U.S. Air Force Research Laboratory 5SAIC Introduction:

MgB2 magnetometer with a directly coupled pick-up loop

NASA Astrophysics Data System (ADS)

Portesi, C.; Mijatovic, D.; Veldhuis, D.; Brinkman, A.; Monticone, E.; Gonnelli, R. S.

2006-05-01

In this work, we show the results obtained in the fabrication and characterization of an MgB2 magnetometer with a directly coupled pick-up loop. We used an all in situ technique for fabricating magnesium diboride films, which consists of the co-evaporation of B and Mg by means of an e-gun and a resistive heater respectively. Consequently, we realized the superconducting device, which incorporates two nanobridges as weak links in a superconducting loop. The nanobridges were realized by focused ion beam milling; they were 240 nm wide and had a critical current density of 107 A cm-2. The magnetometer was characterized at different temperatures and also measurements of the noise levels have been performed. The device shows Josephson quantum interference up to 20 K and the calculated effective area at low temperatures was 0.24 mm2. The transport properties of the magnetometer allow determining fundamental materials properties of the MgB2 thin films, such as the penetration depth.

Comparison of Iron and Tungsten Based Oxygen Carriers for Hydrogen Production Using Chemical Looping Reforming

NASA Astrophysics Data System (ADS)

Khan, M. N.; Shamim, T.

2017-08-01

Hydrogen production by using a three reactor chemical looping reforming (TRCLR) technology is an innovative and attractive process. Fossil fuels such as methane are the feedstocks used. This process is similar to a conventional steam-methane reforming but occurs in three steps utilizing an oxygen carrier. As the oxygen carrier plays an important role, its selection should be done carefully. In this study, two oxygen carrier materials of base metal iron (Fe) and tungsten (W) are analysed using a thermodynamic model of a three reactor chemical looping reforming plant in Aspen plus. The results indicate that iron oxide has moderate oxygen carrying capacity and is cheaper since it is abundantly available. In terms of hydrogen production efficiency, tungsten oxide gives 4% better efficiency than iron oxide. While in terms of electrical power efficiency, iron oxide gives 4.6% better results than tungsten oxide. Overall, a TRCLR system with iron oxide is 2.6% more efficient and is cost effective than the TRCLR system with tungsten oxide.

A study of acoustic heating and forced convection in the solar corona

NASA Technical Reports Server (NTRS)

Foukal, P. V.

1980-01-01

The S055 EUV spectra was used to perform emission measure and line intensity ratio analyses of loop plasma conditions in a study on the thermodynamics of magnetic loops in the solar corona. The evidence that loops contain plasma hotter than the background corona, and thus, require enhanced local dissipation of magnetic or mechanical energy is discussed. The S055 EUV raster pictures were used to study physical conditions in cool ultraviolet absorbing clouds in the solar corona, and optical data were used to derive constraints on the dimension, time scales and optical depths in dark opaque clouds not seen in H alpha and CaK as filaments or prominences. Theoretical modelling of propagation of magnetically guided acoustic shocks in the solar chromosphere finds it still unlikely that high frequency acoustic shocks could reach the solar corona. Dynamic modelling of spicules shows that such guided slow mode shocks can explain the acceleration of cool spicular material seen high in the corona.

A Novel Amyloid Designable Scaffold and Potential Inhibitor Inspired by GAIIG of Amyloid Beta and the HIV-1 V3 loop.

PubMed

Kokotidou, C; Jonnalagadda, S V R; Orr, A A; Seoane-Blanco, M; Apostolidou, C P; van Raaij, M J; Kotzabasaki, M; Chatzoudis, A; Jakubowski, J M; Mossou, E; Forsyth, V T; Mitchell, E P; Bowler, M W; Llamas-Saiz, A L; Tamamis, P; Mitraki, A

2018-05-17

The GAIIG sequence, common to the amyloid beta peptide (residues 29-33) and to the HIV gp 120 (residues 24-28 in a typical V3 loop) self-assembles into amyloid fibrils, as suggested by theory and the experiments presented here. The longer YATGAIIGNII sequence from the V3 loop also self-assembles into amyloid fibrils, of which the first three and the last two residues are outside the amyloid GAIIG core. We postulate that this sequence, with suitable selected replacements at the flexible positions, can serve as a designable scaffold for novel amyloid-based materials. Moreover, we report the single X-ray crystal structure of the beta-breaker peptide GAIPIG at 1.05 Å resolution. This structural information could serve as the basis for structure-based design of potential inhibitors of amyloid formation. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Closed-loop recycling of construction and demolition waste in Germany in view of stricter environmental threshold values.

PubMed

Weil, Marcel; Jeske, Udo; Schebek, Liselotte

2006-06-01

Recycling of construction and demolition waste contributes decisively to the saving of natural mineral resources. In Germany, processed mineral construction and demolition waste from structural engineering is used nearly exclusively in civil engineering (earthwork and road construction sector) as open-loop recycling. Due to the planned stricter limit values for the protection of soil and water, however, this recycling path in civil engineering may no longer be applicable in the future. According to some new guidelines and standards adopted recently, recycled aggregates may also be used for concrete production in the structural engineering sector (closed-loop recycling). Wastes from the structural engineering sector can thus be kept in a closed cycle, and their disposal on a landfill can be avoided. The present report focuses on the determination of maximum waste volumes that may be handled by this new recycling option. Potential adverse effects on the saving of resources and climate protection have been analysed. For this purpose, materials flow analysis and ecobalancing methods have been used.

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

Rikvold, Per Arne; Brown, Gregory; Miyashita, Seiji

Phase diagrams and hysteresis loops were obtained by Monte Carlo simulations and a mean- field method for a simplified model of a spin-crossovermaterialwith a two-step transition between the high-spin and low-spin states. This model is a mapping onto a square-lattice S = 1/2 Ising model with antiferromagnetic nearest-neighbor and ferromagnetic Husimi-Temperley ( equivalent-neighbor) long-range interactions. Phase diagrams obtained by the two methods for weak and strong long-range interactions are found to be similar. However, for intermediate-strength long-range interactions, the Monte Carlo simulations show that tricritical points decompose into pairs of critical end points and mean-field critical points surrounded by horn-shapedmore » regions of metastability. Hysteresis loops along paths traversing the horn regions are strongly reminiscent of thermal two-step transition loops with hysteresis, recently observed experimentally in several spin-crossover materials. As a result, we believe analogous phenomena should be observable in experiments and simulations for many systems that exhibit competition between local antiferromagnetic-like interactions and long-range ferromagnetic-like interactions caused by elastic distortions.« less

Experiments with planar inductive ion source meant for creation of H+ beams.

PubMed

Vainionpaa, J H; Kalvas, T; Hahto, S K; Reijonen, J

2007-06-01

In this article the effects of different engineering parameters of rf-driven ion sources with an external spiral antenna and a quartz rf window are studied. This article consists of three main topics: the effect of source geometry on the operation gas pressure, the effect of source materials and magnetic confinement on extracted current density and ion species, and the effect of different antenna geometries on the extracted current density. The effect of source geometry was studied using three cylindrical plasma chambers with different inner diameters. The chamber materials were studied using two materials, aluminum (Al) and alumina (Al(2)O(3)). The removable 14 magnet multicusp confinement arrangement enabled us to compare the effects of the two wall materials with and without the magnetic confinement. The highest measured proton fractions were measured using Al(2)O(3) plasma chamber and no multicusp confinement. For the compared ion sources the source with multicusp confinement and Al(2)O(3) plasma chamber yields the highest current densities. Multicusp confinement increased the maximum extracted current by up to a factor of 2. Plasma production with different antenna geometries were also studied. The highest current density was achieved using 4.5 loop solenoid antenna with 6.0 cm diameter. A slightly lower current density with lower pressure was achieved using a tightly wound 3 loop spiral antenna with 3.3 cm inner diameter and 6 cm outer diameter.

Dose-Volume Histogram Predictors of Chronic Gastrointestinal Complications After Radical Hysterectomy and Postoperative Concurrent Nedaplatin-Based Chemoradiation Therapy for Early-Stage Cervical Cancer

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

Isohashi, Fumiaki, E-mail: isohashi@radonc.med.osaka-u.ac.jp; Yoshioka, Yasuo; Mabuchi, Seiji

2013-03-01

Purpose: The purpose of this study was to evaluate dose-volume histogram (DVH) predictors for the development of chronic gastrointestinal (GI) complications in cervical cancer patients who underwent radical hysterectomy and postoperative concurrent nedaplatin-based chemoradiation therapy. Methods and Materials: This study analyzed 97 patients who underwent postoperative concurrent chemoradiation therapy. The organs at risk that were contoured were the small bowel loops, large bowel loop, and peritoneal cavity. DVH parameters subjected to analysis included the volumes of these organs receiving more than 15, 30, 40, and 45 Gy (V15-V45) and their mean dose. Associations between DVH parameters or clinical factors andmore » the incidence of grade 2 or higher chronic GI complications were evaluated. Results: Of the clinical factors, smoking and low body mass index (BMI) (<22) were significantly associated with grade 2 or higher chronic GI complications. Also, patients with chronic GI complications had significantly greater V15-V45 volumes and higher mean dose of the small bowel loops compared with those without GI complications. In contrast, no parameters for the large bowel loop or peritoneal cavity were significantly associated with GI complications. Results of the receiver operating characteristics (ROC) curve analysis led to the conclusion that V15-V45 of the small bowel loops has high accuracy for prediction of GI complications. Among these parameters, V40 gave the highest area under the ROC curve. Finally, multivariate analysis was performed with V40 of the small bowel loops and 2 other clinical parameters that were judged to be potential risk factors for chronic GI complications: BMI and smoking. Of these 3 parameters, V40 of the small bowel loops and smoking emerged as independent predictors of chronic GI complications. Conclusions: DVH parameters of the small bowel loops may serve as predictors of grade 2 or higher chronic GI complications after postoperative concurrent nedaplatin-based chemoradiation therapy for early-stage cervical cancer.« less

Resolving Turbine Degradation

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

Walker, Matthew; Kruizenga, Alan Michael; Withey, Elizabeth Ann

2017-08-01

The supercritical carbon dioxide (S-CO2) Brayton Cycle has gained significant attention in the last decade as an advanced power cycle capable of achieving high efficiency power conversion. Sandia National Laboratories, with support from the U.S. Department of Energy Office of Nuclear Energy (US DOE-NE), has been conducting research and development in order to deliver a technology that is ready for commercialization. Root cause analysis has been performed on the Recompression Loop at Sandia National Laboratories. It was found that particles throughout the loop are stainless steel, likely alloy 316 based upon the elemental composition. Deployment of a filter scheme ismore » underway to both protect the turbomachinery and also for purposes of determining the specific cause for the particulate. Shake down tests of electric resistance (ER) as a potential in-situ monitoring scheme shows promise in high temperature systems. A modified instrument was purchased and held at 650°C for more than 1.5 months to date without issue. Quantitative measurements of this instrument will be benchmarked against witness samples in the future, but all qualitative trends to date are as to be expected. ER is a robust method for corrosion monitoring, but very slow at responding and can take several weeks under conditions to see obvious changes in behavior. Electrochemical noise was identified as an advanced technique that should be pursued for the ability to identify transients that would lead to poor material performance.« less

A global multiscale mathematical model for the human circulation with emphasis on the venous system.

PubMed

Müller, Lucas O; Toro, Eleuterio F

2014-07-01

We present a global, closed-loop, multiscale mathematical model for the human circulation including the arterial system, the venous system, the heart, the pulmonary circulation and the microcirculation. A distinctive feature of our model is the detailed description of the venous system, particularly for intracranial and extracranial veins. Medium to large vessels are described by one-dimensional hyperbolic systems while the rest of the components are described by zero-dimensional models represented by differential-algebraic equations. Robust, high-order accurate numerical methodology is implemented for solving the hyperbolic equations, which are adopted from a recent reformulation that includes variable material properties. Because of the large intersubject variability of the venous system, we perform a patient-specific characterization of major veins of the head and neck using MRI data. Computational results are carefully validated using published data for the arterial system and most regions of the venous system. For head and neck veins, validation is carried out through a detailed comparison of simulation results against patient-specific phase-contrast MRI flow quantification data. A merit of our model is its global, closed-loop character; the imposition of highly artificial boundary conditions is avoided. Applications in mind include a vast range of medical conditions. Of particular interest is the study of some neurodegenerative diseases, whose venous haemodynamic connection has recently been identified by medical researchers. Copyright © 2014 John Wiley & Sons, Ltd.

Evidence for two-loop interaction from IRIS and SDO observations of penumbral brightenings

NASA Astrophysics Data System (ADS)

Alissandrakis, C. E.; Koukras, A.; Patsourakos, S.; Nindos, A.

2017-07-01

Aims: We investigate small scale energy release events which can provide clues on the heating mechanism of the solar corona. Methods: We analyzed spectral and imaging data from the Interface Region Imaging Spectrograph (IRIS), images from the Atmospheric Imaging Assembly (AIA) aboard the Solar Dynamics Observatoty (SDO), and magnetograms from the Helioseismic and Magnetic Imager (HMI) aboard SDO. Results: We report observations of small flaring loops in the penumbra of a large sunspot on July 19, 2013. Our main event consisted of a loop spanning 15'', from the umbral-penumbral boundary to an opposite polarity region outside the penumbra. It lasted approximately 10 min with a two minute impulsive peak and was observed in all AIA/SDO channels, while the IRIS slit was located near its penumbral footpoint. Mass motions with an apparent velocity of 100 km s-1 were detected beyond the brightening, starting in the rise phase of the impulsive peak; these were apparently associated with a higher-lying loop. We interpret these motions in terms of two-loop interaction. IRIS spectra in both the C II and Si iv lines showed very extended wings, up to about 400 km s-1, first in the blue (upflows) and subsequently in the red wing. In addition to the strong lines, emission was detected in the weak lines of Cl I, O I and C I, as well as in the Mg II triplet lines. Absorption features in the profiles of the C II doublet, the Si iv doublet and the Mg II h and k lines indicate the existence of material with a lower source function between the brightening and the observer. We attribute this absorption to the higher loop and this adds further credibility to the two-loop interaction hypothesis. Tilts were detected in the absorption spectra, as well as in the spectra of Cl I, O I, and C I lines, possibly indicating rotational motions from the untwisting of magnetic flux tubes. Conclusions: We conclude that the absorption features in the C II, Si iv and Mg II profiles originate in a higher-lying, descending loop; as this approached the already activated lower-lying loop, their interaction gave rise to the impulsive peak, the very broad line profiles and the mass motions. Movies associated to Figs. A.1-A.3 are available at http://www.aanda.org

A mechanical comparison of linear and double-looped hung supplemental heavy chain resistance to the back squat: a case study.

PubMed

Neelly, Kurt R; Terry, Joseph G; Morris, Martin J

2010-01-01

A relatively new and scarcely researched technique to increase strength is the use of supplemental heavy chain resistance (SHCR) in conjunction with plate weights to provide variable resistance to free weight exercises. The purpose of this case study was to determine the actual resistance being provided by a double-looped versus a linear hung SHCR to the back squat exercise. The linear technique simply hangs the chain directly from the bar, whereas the double-looped technique uses a smaller chain to adjust the height of the looped chain. In both techniques, as the squat descends, chain weight is unloaded onto the floor, and as the squat ascends, chain weight is progressively loaded back as resistance. One experienced and trained male weight lifter (age = 33 yr; height = 1.83 m; weight = 111.4 kg) served as the subject. Plate weight was set at 84.1 kg, approximately 50% of the subject's 1 repetition maximum. The SHCR was affixed to load cells, sampling at a frequency of 500 Hz, which were affixed to the Olympic bar. Data were collected as the subject completed the back squat under the following conditions: double-looped 1 chain (9.6 kg), double-looped 2 chains (19.2 kg), linear 1 chain, and linear 2 chains. The double-looped SHCR resulted in a 78-89% unloading of the chain weight at the bottom of the squat, whereas the linear hanging SHCR resulted in only a 36-42% unloading. The double-looped technique provided nearly 2 times the variable resistance at the top of the squat compared with the linear hanging technique, showing that attention must be given to the technique used to hang SHCR.

A New Sliding-Loop Technique in Renorrhaphy for Partial Nephrectomy: A Feasibility Study in a Porcine Model.

PubMed

Lee, Jung Keun; Oh, Jong Jin; Lee, Sangchul; Lee, Seung Bae; Byun, Seok-Soo; Lee, Sang Eun; Jeong, Chang Wook

2016-04-01

We developed a sliding-loop technique that narrowed both sides of the parenchyma in a porcine model and compared it with the conventional sliding-clip technique. Three pigs (30-40 kg) were reused following another experiment conducted by the same researchers. Bilateral kidneys were harvested within 30 minutes after euthanasia. Two partial nephrectomies per kidney were performed on opposite surfaces. All kidney defects were of the same size (diameter of 2.5-3 cm with a depth of 1.0-1.5 cm). The sliding-clip technique and sliding-loop technique were performed separately. In the sliding-loop technique, we created a 1-cm loop at the end of a Vicryl and placed a tetrafluoroethylene polymer pledget in front of the knots passing through the needle. The needle then crossed the loop after passing through the renal parenchyma. A Weck clip was placed and slid on one side to tighten the suture. Tightening was controlled with an equivalent force using a digital push-pull gauge. Three stitches were placed at each renorrhaphy site. The distance between repaired renal surfaces was measured at 5 different points (3 suture sites and 2 middle sites between sutures). The results of the 2 techniques were compared by using the independent t test. The mean distance between renal surfaces was significantly narrower in the sliding-loop technique than in the conventional technique (1.80 ± 1.08 mm vs 5.28 ± 2.46 mm, P < .001). In the porcine model, the sliding-loop technique more effectively closed the partial nephrectomy defects compared with the conventional sliding-clip technique. © The Author(s) 2015.

Triggering of solar magnetic eruptions on various size scales

NASA Astrophysics Data System (ADS)

Sterling, Alphonse

A solar eruption that produces a coronal mass ejection (CME) together with a flare is driven by the eruption of a closed-loop magnetic arcade that has a sheared-field core. Before eruption, the sheared core envelops a polarity inversion line along which cool filament material may reside. The sheared-core arcade erupts when there is a breakdown in the balance between the confining downward-directed magnetic tension of the overall arcade field and the upward-directed force of the pent-up magnetic pressure of the sheared field in the core of the arcade. What triggers the breakdown in this balance in favor of the upward-directed force is still an unsettled question. We consider several eruption examples, using imaging data from the SoHO, TRACE and Hinode satellites, and other sources, along with information about the magnetic field of the erupting regions. In several cases, observations of large-scale eruptions, where the magnetic neutral line spans ˜ few ×10,000 km, are consistent with magnetic flux cancelation being the trigger to the eruption's onset, even though the amount of flux canceled is only ˜ few percent of the total magnetic flux of the erupting region. In several other cases, an initial compact (small size-scale) eruption occurs embedded inside of a larger closed magnetic loop system, so that the smaller eruption destabilizes and causes the eruption of the much larger system. In this way, small-scale eruptive events can result in eruption of much larger-scale systems. This work was funded by NASA's Science Mission Directorate thought the Living With a Star Targeted Research and Technology Program, the Supporting Research and Program, and the Hinode project.

Loop Mirror Laser Neural Network with a Fast Liquid-Crystal Display

NASA Astrophysics Data System (ADS)

Mos, Evert C.; Schleipen, Jean J. H. B.; de Waardt, Huug; Khoe, Djan G. D.

1999-07-01

In our laser neural network (LNN) all-optical threshold action is obtained by application of controlled optical feedback to a laser diode. Here an extended experimental LNN is presented with as many as 32 neurons and 12 inputs. In the setup we use a fast liquid-crystal display to implement an optical matrix vector multiplier. This display, based on ferroelectric liquid-crystal material, enables us to present 125 training examples s to the LNN. To maximize the optical feedback efficiency of the setup, a loop mirror is introduced. We use a -rule learning algorithm to train the network to perform a number of functions toward the application area of telecommunication data switching.

Treatment of low strains and long hold times in high temperature metal fatigue by strainrange partitioning

NASA Technical Reports Server (NTRS)

Manson, S. S.; Zab, R.

1977-01-01

A procedure for treating creep-fatigue for low strainranges and long hold times is outlined. A semi-experimental approach, wherein several cycles of the imposed loading is actually applied to a specimen in order to determine the stable hysteresis loop, can be very useful in the analysis. Because such tests require only a small fraction of the total failure time, they are not inherently prohibitive if experimental equipment is available. The need for accurate constitutive equations is bypassed because the material itself acts to translate the imposed loading into the responsive hysteresis loops. When strainrange partitioning has been applied in such cases very good results have been obtained.

Investigation of creep by use of closed loop servo-hydraulic test system

NASA Technical Reports Server (NTRS)

Wu, H. C.; Yao, J. C.

1981-01-01

Creep tests were conducted by means of a closed loop servo-controlled materials test system. These tests are different from the conventional creep tests in that the strain history prior to creep may be carefully monitored. Tests were performed for aluminum alloy 6061-0 at 150 C and monitored by a PDP 11/04 minicomputer at a preset constant plastic-strain rate prehistory. The results show that the plastic-strain rate prior to creep plays a significant role in creep behavior. The endochronic theory of viscoplasticity was applied to describe the observed creep curves. The concepts of intrinsic time and strain rate sensitivity function are employed and modified according to the present observation.

Magnetic refrigeration apparatus with belt of ferro or paramagnetic material

DOEpatents

Barclay, John A.; Stewart, Walter F.; Henke, Michael D.; Kalash, Kenneth E.

1987-01-01

A magnetic refrigerator operating in the 12 to 77K range utilizes a belt which carries ferromagnetic or paramagnetic material and which is disposed in a loop which passes through the center of a solenoidal magnet to achieve cooling. The magnetic material carried by the belt, which can be blocks in frames of a linked belt, can be a mixture of substances with different Curie temperatures arranged such that the Curie temperatures progressively increase from one edge of the belt to the other. This magnetic refrigerator can be used to cool and liquefy hydrogen or other fluids.

Magnetic refrigeration apparatus with belt of ferro or paramagnetic material

DOEpatents

Barclay, J.A.; Stewart, W.F.; Henke, M.D.; Kalash, K.E.

1986-04-03

A magnetic refrigerator operating in the 12 to 77 K range utilizes a belt which carries ferromagnetic or paramagnetic material and which is disposed in a loop which passes through the center of a solenoidal magnet to achieve cooling. The magnetic material carried by the belt, which can be blocks in frames of a linked belt, can be a mixture of substances with different Curie temperatures arranged such that the Curie temperatures progressively increase from one edge of the belt to the other. This magnetic refrigerator can be used to cool and liquefy hydrogen or other fluids.

A taxonomic framework for assessing governance challenges and environmental effects of integrated food-energy systems.

PubMed

Gerst, Michael D; Cox, Michael E; Locke, Kim A; Laser, Mark; Kapuscinski, Anne R

2015-01-20

Predominant forms of food and energy systems pose multiple challenges to the environment as current configurations tend to be structured around centralized one-way through-put of materials and energy. In addition, these configurations can introduce vulnerability to input material price and supply shocks as well as contribute to localized food insecurity and lost opportunities for less environmentally harmful forms of local economic development. One proposed form of system transformation involves locally integrating “unclosed” material and energy loops from food and energy systems. Such systems, which have been termed integrated food-energy systems (IFES), have existed in diverse niche forms but have not been systematically studied with respect to technological, governance, and environmental differences. As a first step in this process, we have constructed a taxonomy of IFES archetypes by using exploratory data analysis on a collection of IFES cases. We find that IFES may be classified hierarchically first by their primary purpose—food or energy production—and subsequently by degree and direction of vertical supply chain coordination. We then use this taxonomy to delineate potential governance challenges and pose a research agenda aimed at understanding what role IFES may play in food and energy system transformation and ultimately what policies may encourage IFES adoption.

Knowledge Generated by Audiovisual Narrative Action Research Loops

ERIC Educational Resources Information Center

Bautista Garcia-Vera, Antonio

2012-01-01

We present data collected from the research project funded by the Ministry of Education and Science of Spain entitled "Audiovisual Narratives and Intercultural Relations in Education." One of the aims of the research was to determine the nature of thought processes occurring during audiovisual narratives. We studied the possibility of…

Parameter Identification Flight Test Maneuvers for Closed Loop Modeling of the F-18 High Alpha Research Vehicle (HARV)

NASA Technical Reports Server (NTRS)

Batterson, James G. (Technical Monitor); Morelli, E. A.

1996-01-01

Flight test maneuvers are specified for the F-18 High Alpha Research Vehicle (HARV). The maneuvers were designed for closed loop parameter identification purposes, specifically for longitudinal and lateral linear model parameter estimation at 5,20,30,45, and 60 degrees angle of attack, using the Actuated Nose Strakes for Enhanced Rolling (ANSER) control law in Thrust Vectoring (TV) mode. Each maneuver is to be realized by applying square wave inputs to specific pilot station controls using the On-Board Excitation System (OBES). Maneuver descriptions and complete specifications of the time / amplitude points defining each input are included, along with plots of the input time histories.

Experimental Research on Seismic Performance of Four-Element Variable Cross-Sectional Concrete Filled Steel Tubular Laced Columns

NASA Astrophysics Data System (ADS)

Ou, Zhijing; Lin, Jianmao; Chen, Shengfu; Lin, Wen

2017-10-01

A total of 7 experimental tests were conducted to investigate seismic performance of four element variable cross-sectional Concrete Filled Steel Tubular (CFST) laced columns. The experimental parameters are longitudinal slope and arrangement type of lacing tubes. The rules on hysteresis loop, ductility, energy expenditure, and stiffness degradation of specimens are researched. Test results indicate that all specimens have good seismic performance; their hysteresis loops are full without obvious shrinkage. With the increase of longitudinal slope, the horizontal carrying capacity increases, energy dissipation capacity improve, and there is slightly increase in stiffness degradation. The influence of arrangement type of lacing tubes on displacement ductility of specimens is big.

Impact of loop-tail ureteral stents on ureteral stent-related symptoms immediately after ureteroscopic lithotripsy: Comparison with pigtail ureteral stents

PubMed Central

Inoue, Takaaki; Muguruma, Kouei; Murota, Takashi; Kinoshita, Hidefumi; Matsuda, Tadashi

2017-01-01

Purpose To evaluate urination-related quality of life (QoL) in patients with an indwelling ureteral stent immediately after ureteroscopic lithotripsy (URSL) for upper urinary calculi. We compared the effects of loop-tail and pigtail ureteral stents on urination-related QoL. Materials and Methods Of 135 patients who underwent URSL between May 2014 and March 2015 at our hospital, we retrospectively analyzed the records of 70 patients (42 men, 28 women; median age, 63 years) in whom the stent tail was positioned inside the bladder without crossing the midline and who completed the core lower urinary tract symptoms score (CLSS) questionnaire pre- and postoperatively. Results There were significant differences in incomplete emptying (p=0.048) and bladder pain (p=0.041) between patients with loop-tail versus pigtail ureteral stents after URSL. In the multivariate analysis, stent type had a stronger association with incomplete emptying (p=0.022) and bladder pain (p=0.018) than age, sex, body mass index, stent side, operation time, diameter of ureteral access sheath, and stent type. Conclusions Patients with loop-tail ureteral stents had better urination-related QoL in the immediate post-URSL stage than patients with pigtail stents. PMID:29124244

Mini-filament Eruptions Triggering Confined Solar Flares Observed by ONSET and SDO

NASA Astrophysics Data System (ADS)

Yang, Shuhong; Zhang, Jun

2018-06-01

Using the observations from the Optical and Near-infrared Solar Eruption Tracer (ONSET) and the Solar Dynamics Observatory (SDO), we study an M5.7 flare in AR 11476 on 2012 May 10 and a micro-flare in the quiet Sun on 2017 March 23. Before the onset of each flare, there is a reverse S-shaped filament above the polarity inversion line, then the filaments become unstable and begin to rise. The rising filaments gain the upper hand over the tension force of the dome-like overlying loops and thus successfully erupt outward. The footpoints of the reconnecting overlying loops successively brighten and are observed as two flare ribbons, while the newly formed low-lying loops appear as post-flare loops. These eruptions are similar to the classical model of successful filament eruptions associated with coronal mass ejections (CMEs). However, the erupting filaments in this study move along large-scale lines and eventually reach the remote solar surface; i.e., no filament material is ejected into the interplanetary space. Thus, both the flares are confined. These results reveal that some successful filament eruptions can trigger confined flares. Our observations also imply that this kind of filament eruption may be ubiquitous on the Sun, from active regions (ARs) with large flares to the quiet Sun with micro-flares.

Energy-Looping Nanoparticles: Harnessing Excited-State Absorption for Deep-Tissue Imaging.

PubMed

Levy, Elizabeth S; Tajon, Cheryl A; Bischof, Thomas S; Iafrati, Jillian; Fernandez-Bravo, Angel; Garfield, David J; Chamanzar, Maysamreza; Maharbiz, Michel M; Sohal, Vikaas S; Schuck, P James; Cohen, Bruce E; Chan, Emory M

2016-09-27

Near infrared (NIR) microscopy enables noninvasive imaging in tissue, particularly in the NIR-II spectral range (1000-1400 nm) where attenuation due to tissue scattering and absorption is minimized. Lanthanide-doped upconverting nanocrystals are promising deep-tissue imaging probes due to their photostable emission in the visible and NIR, but these materials are not efficiently excited at NIR-II wavelengths due to the dearth of lanthanide ground-state absorption transitions in this window. Here, we develop a class of lanthanide-doped imaging probes that harness an energy-looping mechanism that facilitates excitation at NIR-II wavelengths, such as 1064 nm, that are resonant with excited-state absorption transitions but not ground-state absorption. Using computational methods and combinatorial screening, we have identified Tm(3+)-doped NaYF4 nanoparticles as efficient looping systems that emit at 800 nm under continuous-wave excitation at 1064 nm. Using this benign excitation with standard confocal microscopy, energy-looping nanoparticles (ELNPs) are imaged in cultured mammalian cells and through brain tissue without autofluorescence. The 1 mm imaging depths and 2 μm feature sizes are comparable to those demonstrated by state-of-the-art multiphoton techniques, illustrating that ELNPs are a promising class of NIR probes for high-fidelity visualization in cells and tissue.

Soft container for explosive nuts

NASA Technical Reports Server (NTRS)

Glenn, D. C.; Drummond, W. E.; Miller, G.

1981-01-01

Flexible fabric fits over variety of assembly shapes to contain debris produced by detonations or safety tests. Bag material is woven multifilament polyamide or aramid. Belt loops hold bag to clamp. Ring supports explosive nut structure and detonator wires, and after nut is mounted, bag and clamp are slipped over ring and fastened.

Self-Paced Physics, Segments 28-31.

ERIC Educational Resources Information Center

New York Inst. of Tech., Old Westbury.

Four study segments of the Self-Paced Physics Course materials are presented in this sixth problems and solutions book used as a part of student course work. The subject matter is related to electric currents, current densities, resistances, Ohm's law, voltages, Joule heating, electromotive forces, single loop circuits, series and parallel…

Ultrafiltrative deinking of flexographic ONP : the role of surfactants

Treesearch

Bradley H. Upton; Gopal A. Krishnagopalan; Said Abubakr

1999-01-01

Ultrafiltration is a potentially viable method of removing finely dispersed flexographic pigments from the deinking water loop. This work examines the effects of surface-active materials on ultrafiltration efficiency. A logarithmic relationship between permeate flax and pigment concentration was demonstrated at ink concentrations above 0.4%, permeation rates becoming...

Integration of Haptics in Agricultural Robotics

NASA Astrophysics Data System (ADS)

Kannan Megalingam, Rajesh; Sreekanth, M. M.; Sivanantham, Vinu; Sai Kumar, K.; Ghanta, Sriharsha; Surya Teja, P.; Reddy, Rajesh G.

2017-08-01

Robots can differentiate with open loop system and closed loop system robots. We face many problems when we do not have a feedback from robots. In this research paper, we are discussing all possibilities to achieve complete closed loop system for Multiple-DOF Robotic Arm, which is used in a coconut tree climbing and cutting robot by introducing a Haptic device. We are working on various sensors like tactile, vibration, force and proximity sensors for getting feedback. For monitoring the robotic arm achieved by graphical user interference software which simulates the working of the robotic arm, send the feedback of all the real time analog values which are produced by various sensors and provide real-time graphs for estimate the efficiency of the Robot.

Stereoscopic distance perception

NASA Technical Reports Server (NTRS)

Foley, John M.

1989-01-01

Limited cue, open-loop tasks in which a human observer indicates distances or relations among distances are discussed. By open-loop tasks, it is meant tasks in which the observer gets no feedback as to the accuracy of the responses. What happens when cues are added and when the loop is closed are considered. The implications of this research for the effectiveness of visual displays is discussed. Errors in visual distance tasks do not necessarily mean that the percept is in error. The error could arise in transformations that intervene between the percept and the response. It is argued that the percept is in error. It is also argued that there exist post-perceptual transformations that may contribute to the error or be modified by feedback to correct for the error.

Research on Modelling of Aviation Piston Engine for the Hardware-in-the-loop Simulation

NASA Astrophysics Data System (ADS)

Yu, Bing; Shu, Wenjun; Bian, Wenchao

2016-11-01

In order to build the aero piston engine model which is real-time and accurate enough to operating conditions of the real engine for hardware in the loop simulation, the mean value model is studied. Firstly, the air-inlet model, the fuel model and the power-output model are established separately. Then, these sub models are combined and verified in MATLAB/SIMULINK. The results show that the model could reflect the steady-state and dynamic performance of aero engine, the errors between the simulation results and the bench test data are within the acceptable range. The model could be applied to verify the logic performance and control strategy of controller in the hardware-in-the-loop (HIL) simulation.

Integrated otpical monitoring of MEMS for closed-loop control

NASA Astrophysics Data System (ADS)

Dawson, Jeremy M.; Wang, Limin; McCormick, W. B.; Rittenhouse, S. A.; Famouri, Parviz F.; Hornak, Lawrence A.

2003-01-01

Robust control and failure assessment of MEMS employed in physically demanding, mission critical applications will allow for higher degrees of quality assurance in MEMS operation. Device fault detection and closed-loop control require detailed knowledge of the operational states of MEMS over the lifetime of the device, obtained by a means decoupled from the system. Preliminary through-wafer optical monitoring research efforts have shown that through-wafer optical probing is suitable for characterizing and monitoring the behavior of MEMS, and can be implemented in an integrated optical monitoring package for continuous in-situ device monitoring. This presentation will discuss research undertaken to establish integrated optical device metrology for closed-loop control of a MUMPS fabricated lateral harmonic oscillator. Successful linear closed-loop control results using a through-wafer optical microprobe position feedback signal will be presented. A theoretical optical output field intensity study of grating structures, fabricated on the shuttle of the resonator, was performed to improve the position resolution of the optical microprobe position signal. Through-wafer microprobe signals providing a positional resolution of 2 μm using grating structures will be shown, along with initial binary Fresnel diffractive optical microelement design layout, process development, and testing results. Progress in the design, fabrication, and test of integrated optical elements for multiple microprobe signal delivery and recovery will be discussed, as well as simulation of device system model parameter changes for failure assessment.

The development of the DAST I remotely piloted research vehicle for flight testing an active flutter suppression control system. Ph.D. Thesis. Final Report

NASA Technical Reports Server (NTRS)

Grose, D. L.

1979-01-01

The development of the DAST I (drones for aerodynamic and structural testing) remotely piloted research vehicle is described. The DAST I is a highly modified BQM-34E/F Firebee II Supersonic Aerial Target incorporating a swept supercritical wing designed to flutter within the vehicle's flight envelope. The predicted flutter and rigid body characteristics are presented. A description of the analysis and design of an active flutter suppression control system (FSS) designed to increase the flutter boundary of the DAST wing (ARW-1) by a factor of 20% is given. The design and development of the digital remotely augmented primary flight control system and on-board analog backup control system is presented. An evaluation of the near real-time flight flutter testing methods is made by comparing results of five flutter testing techniques on simulated DAST I flutter data. The development of the DAST ARW-1 state variable model used to generate time histories of simulated accelerometer responses is presented. This model uses control surface commands and a Dryden model gust as inputs. The feasibility of the concept of extracting open loop flutter characteristics from closed loop FSS responses was examined. It was shown that open loop characteristics can be determined very well from closed loop subcritical responses.

Evaluation of an Adaptive Game that Uses EEG Measures Validated during the Design Process as Inputs to a Biocybernetic Loop.

PubMed

Ewing, Kate C; Fairclough, Stephen H; Gilleade, Kiel

2016-01-01

Biocybernetic adaptation is a form of physiological computing whereby real-time data streaming from the brain and body is used by a negative control loop to adapt the user interface. This article describes the development of an adaptive game system that is designed to maximize player engagement by utilizing changes in real-time electroencephalography (EEG) to adjust the level of game demand. The research consists of four main stages: (1) the development of a conceptual framework upon which to model the interaction between person and system; (2) the validation of the psychophysiological inference underpinning the loop; (3) the construction of a working prototype; and (4) an evaluation of the adaptive game. Two studies are reported. The first demonstrates the sensitivity of EEG power in the (frontal) theta and (parietal) alpha bands to changing levels of game demand. These variables were then reformulated within the working biocybernetic control loop designed to maximize player engagement. The second study evaluated the performance of an adaptive game of Tetris with respect to system behavior and user experience. Important issues for the design and evaluation of closed-loop interfaces are discussed.

Evaluation of an Adaptive Game that Uses EEG Measures Validated during the Design Process as Inputs to a Biocybernetic Loop

PubMed Central

Ewing, Kate C.; Fairclough, Stephen H.; Gilleade, Kiel

2016-01-01

Biocybernetic adaptation is a form of physiological computing whereby real-time data streaming from the brain and body is used by a negative control loop to adapt the user interface. This article describes the development of an adaptive game system that is designed to maximize player engagement by utilizing changes in real-time electroencephalography (EEG) to adjust the level of game demand. The research consists of four main stages: (1) the development of a conceptual framework upon which to model the interaction between person and system; (2) the validation of the psychophysiological inference underpinning the loop; (3) the construction of a working prototype; and (4) an evaluation of the adaptive game. Two studies are reported. The first demonstrates the sensitivity of EEG power in the (frontal) theta and (parietal) alpha bands to changing levels of game demand. These variables were then reformulated within the working biocybernetic control loop designed to maximize player engagement. The second study evaluated the performance of an adaptive game of Tetris with respect to system behavior and user experience. Important issues for the design and evaluation of closed-loop interfaces are discussed. PMID:27242486

Tower reactors for bioconversion of lignocellulosic material

DOEpatents

Nguyen, Q.A.

1998-03-31

An apparatus is disclosed for enzymatic hydrolysis and fermentation of pretreated lignocellulosic material. The apparatus consists of a tower bioreactor which has mixers to achieve intermittent mixing of the material. Precise mixing of the material is important for effective heat and mass transfer requirements without damaging or denaturing the enzymes or fermenting microorganisms. The pretreated material, generally in the form of a slurry, is pumped through the bioreactor, either upwards or downwards, and is mixed periodically as it passes through the mixing zones where the mixers are located. For a thin slurry, alternate mixing can be achieved by a pumping loop which also serves as a heat transfer device. Additional heat transfer takes place through the reactor heat transfer jackets. 5 figs.

Tower reactors for bioconversion of lignocellulosic material

DOEpatents

Nguyen, Q.A.

1999-03-30

An apparatus is described for enzymatic hydrolysis and fermentation of pretreated lignocellulosic material, in the form of a tower bioreactor, having mixers to achieve intermittent mixing of the material. Precise mixing of the material is important for effective heat and mass transfer requirements without damaging or denaturing the enzymes or fermenting microorganisms. The pretreated material, generally in the form of a slurry, is pumped through the bioreactor, either upwards or downwards, and is mixed periodically as it passes through the mixing zones where the mixers are located. For a thin slurry, alternate mixing can be achieved by a pumping loop which also serves as a heat transfer device. Additional heat transfer takes place through the reactor heat transfer jackets. 5 figs.

Unfolding thermodynamics of intramolecular G-quadruplexes: base sequence contributions of the loops.

PubMed

Olsen, Chris M; Lee, Hui-Ting; Marky, Luis A

2009-03-05

G-quadruplexes are a highly studied DNA motif with a potential role in a variety of cellular processes and more recently are considered novel targets for drug therapy in aging and anticancer research. In this work, we have investigated the thermodynamic contributions of the loops on the stable formation of G-quadruplexes. Specifically, we use a combination of UV, circular dichroism (CD) and fluorescence spectroscopies, and differential scanning calorimetry (DSC) to determine thermodynamic profiles, including the differential binding of ions and water, for the unfolding of the thrombin aptamer: d(GGT2GGTGTGGT2GG) that is referred to as G2. The sequences in italics, TGT and T2, are known to form loops. Other sequences examined contained base substitutions in the TGT loop (TAT, TCT, TTT, TAPT, and UUU), in the T2 loops (T4, U2), or in both loops (UGU and U2, UUU and U2). The CD spectra of all molecules show a positive band centered at 292 nm, which corresponds to the "chair" conformation. The UV and DSC melting curves of each G-quadruplex show monophasic transitions with transition temperatures (T(M)s) that remained constant with increasing strand concentration, confirming their intramolecular formation. These G-quadruplexes unfold with T(M)s in the range from 43.2 to 56.5 degrees C and endothermic enthalpies from 22.9 to 37.2 kcal/mol. Subtracting the contribution of a G-quartet stack from each experimental profile indicated that the presence of the loops stabilize each G-quadruplex by favorable enthalpy contributions, larger differential binding of K+ ions (0.1-0.6 mol K+/ mol), and a variable uptake/release of water molecules (-6 to 8 mol H2O/mol). The thermodynamic contributions for these specific base substitutions are discussed in terms of loop stacking (base-base stacking within the loops) and their hydration effects.

Closed Field Coronal Heating Models Inspired by Wave Turbulence

NASA Astrophysics Data System (ADS)

Downs, C.; Lionello, R.; Mikic, Z.; Linker, J.; Velli, M. M.

2013-12-01

To simulate the energy balance of coronal plasmas on macroscopic scales, we often require the specification of the coronal heating mechanism in some functional form. To go beyond empirical formulations and to build a more physically motivated heating function, we investigate the wave-turbulence dissipation (WTD) phenomenology for the heating of closed coronal loops. To do so, we employ an implementation of non-WKB equations designed to capture the large-scale propagation, reflection, and dissipation of wave turbulence along a loop. The parameter space of this model is explored by solving the coupled WTD and hydrodynamic equations in 1D for an idealized loop, and the relevance to a range of solar conditions is established by computing solutions for several hundred loops extracted from a realistic 3D coronal field. Due to the implicit dependence of the WTD heating model on loop geometry and plasma properties along the loop and at the footpoints, we find that this model can significantly reduce the number of free parameters when compared to traditional empirical heating models, and still robustly describe a broad range of quiet-sun and active region conditions. The importance of the self-reflection term in producing realistic heating scale heights and thermal non-equilibrium cycles is discussed, and preliminary 3D thermodynamic MHD simulations using this formulation are presented. Research supported by NASA and NSF.

Evaporation of binary mixtures in microgravity

NASA Technical Reports Server (NTRS)

Girgis, Morris; Matta, Nabil; Kolli, Kiran; Brown, Leon; Chubb, Kevin

1995-01-01

The motivation of this research is to obtain a better understanding of phase-change heat transfer within single and binary liquid meniscii, both in 1-g and 0-g environments. During phase 1 and part of phase 2, in a glass test cell with an inclined heated plate, 1-6 experiments on pentane with additions of decane up to 3% were conducted to determine the optimum concentration that will exhibit the maximum heat transfer and stability. During phase 2 emphasis was given to explore fundamental research issues and to ultimately develop a reliable capillary pumped loop (CPL) device for low gravity. In related experimental work, it was found that thermocapillary stresses near the contract line could result in a degraded wettability which ultimately could explain the observed failure of CPL devices in zero-gravity environment. Therefore, the current experimental effort investigates the effect of adding binary constituents in improving the thermocapillary characteristics near the contact line within the loop configuration. Achievements during second phase include: (1) Further enhancement of Central State University's Microgravity Laboratory by adding or improving upon capabilities of photography, video imaging, fluid visualization, and general experimental testing capabilities; (2) Experimental results for the inclined plate cell; (3) Modeling effort with a detailed scaling analysis; (4) Additional testing with a tube loop configuration to extend experimental work by Dickens, et al.; (5) Fabrication of a capillary loop to be tested using binary fluid (pentane/decane). The device that has been recently completed will be set up horizontally so that the effect of gravity on the performance is negligible. Testing will cover a wide range of parameters such as decane/pentane concentration, heat input value, heat input location (below or above meniscus), and loop temperature.

Design of a Closed-Loop, Bidirectional Brain Machine Interface System With Energy Efficient Neural Feature Extraction and PID Control.

PubMed

Liu, Xilin; Zhang, Milin; Richardson, Andrew G; Lucas, Timothy H; Van der Spiegel, Jan

2017-08-01

This paper presents a bidirectional brain machine interface (BMI) microsystem designed for closed-loop neuroscience research, especially experiments in freely behaving animals. The system-on-chip (SoC) consists of 16-channel neural recording front-ends, neural feature extraction units, 16-channel programmable neural stimulator back-ends, in-channel programmable closed-loop controllers, global analog-digital converters (ADC), and peripheral circuits. The proposed neural feature extraction units includes 1) an ultra low-power neural energy extraction unit enabling a 64-step natural logarithmic domain frequency tuning, and 2) a current-mode action potential (AP) detection unit with time-amplitude window discriminator. A programmable proportional-integral-derivative (PID) controller has been integrated in each channel enabling a various of closed-loop operations. The implemented ADCs include a 10-bit voltage-mode successive approximation register (SAR) ADC for the digitization of the neural feature outputs and/or local field potential (LFP) outputs, and an 8-bit current-mode SAR ADC for the digitization of the action potential outputs. The multi-mode stimulator can be programmed to perform monopolar or bipolar, symmetrical or asymmetrical charge balanced stimulation with a maximum current of 4 mA in an arbitrary channel configuration. The chip has been fabricated in 0.18 μ m CMOS technology, occupying a silicon area of 3.7 mm 2 . The chip dissipates 56 μW/ch on average. General purpose low-power microcontroller with Bluetooth module are integrated in the system to provide wireless link and SoC configuration. Methods, circuit techniques and system topology proposed in this work can be used in a wide range of relevant neurophysiology research, especially closed-loop BMI experiments.

Experimental and Numerical Investigation of Pressure Drop in Silicon Carbide Fuel Rod for Application in Pressurized Water Reactors

NASA Astrophysics Data System (ADS)

Abir, Ahmed Musafi

Spacer grids are used in Pressurized Water Reactors (PWRs) fuel assemblies which enhances heat transfer from fuel rods. However, there remain regions of low turbulence in between the spacer grids. To enhance turbulence in these regions surface roughness is applied on the fuel rod walls. Meyer [1] used empirical correlations to predict heat transfer and friction factor for artificially roughened fuel rod bundles at High Performance Light Water Reactors (LWRs). Their applicability was tested by Carrilho at University of South Carolina's (USC) Single Heated Element Loop Tester (SHELT). He attained a heat transfer and friction factor enhancement of 50% and 45% respectively, using Inconel nuclear fuel rods with square transverse ribbed surface. Following him Najeeb conducted a similar study due to three dimensional diamond shaped blocks in turbulent flow. He recorded a maximum heat transfer enhancement of 83%. At present, several types of materials are being used for fuel rod cladding including Zircaloy, Uranium oxide, etc. But researchers are actively searching for new material that can be a more practical alternative. Silicon Carbide (SiC) has been identified as a material of interest for application as fuel rod cladding [2]. The current study deals with the experimental investigation to find out the friction factor increase of a SiC fuel rod with 3D surface roughness. The SiC rod was tested at USC's SHELT loop. The experiment was conducted in turbulent flowing Deionized (DI) water at steady state conditions. Measurements of Flow rate and pressure drop were made. The experimental results were also validated by Computational Fluid Dynamics (CFD) analysis in ANSYS Fluent. To simplify the CFD analysis and to save computational resources the 3D roughness was approximated as a 2D one. The friction factor results of the CFD investigation was found to lie within +/-8% of the experimental results. A CFD model was also run with the energy equation turned on, and a heat generation of 8 kW applied to the rod. A maximum heat transfer enhancement of 18.4% was achieved at the highest flow rate investigated (i.e. Re=109204).

The role of the phonological loop in English word learning: a comparison of Chinese ESL learners and native speakers.

PubMed

Hamada, Megumi; Koda, Keiko

2011-04-01

Although the role of the phonological loop in word-retention is well documented, research in Chinese character retention suggests the involvement of non-phonological encoding. This study investigated whether the extent to which the phonological loop contributes to learning and remembering visually introduced words varies between college-level Chinese ESL learners (N = 20) and native speakers of English (N = 20). The groups performed a paired associative learning task under two conditions (control versus articulatory suppression) with two word types (regularly spelled versus irregularly spelled words) differing in degree of phonological accessibility. The results demonstrated that both groups' recall declined when the phonological loop was made less available (with irregularly spelled words and in the articulatory suppression condition), but the decline was greater for the native group. These results suggest that word learning entails phonological encoding uniformly across learners, but the contribution of phonology varies among learners with diverse linguistic backgrounds.

The effect of jitter on the performance of space coherent optical communication system with Costas loop

NASA Astrophysics Data System (ADS)

Li, Xin; Hong, Yifeng; Wang, Jinfang; Liu, Yang; Sun, Xun; Li, Mi

2018-01-01

Numerous communication techniques and optical devices successfully applied in space optical communication system indicates a good portability of it. With this good portability, typical coherent demodulation technique of Costas loop can be easily adopted in space optical communication system. As one of the components of pointing error, the effect of jitter plays an important role in the communication quality of such system. Here, we obtain the probability density functions (PDF) of different jitter degrees and explain their essential effect on the bit error rate (BER) space optical communication system. Also, under the effect of jitter, we research the bit error rate of space coherent optical communication system using Costas loop with different system parameters of transmission power, divergence angle, receiving diameter, avalanche photodiode (APD) gain, and phase deviation caused by Costas loop. Through a numerical simulation of this kind of communication system, we demonstrate the relationship between the BER and these system parameters, and some corresponding methods of system optimization are presented to enhance the communication quality.

First Results from a Hardware-in-the-Loop Demonstration of Closed-Loop Autonomous Formation Flying

NASA Technical Reports Server (NTRS)

Gill, E.; Naasz, Bo; Ebinuma, T.

2003-01-01

A closed-loop system for the demonstration of formation flying technologies has been developed at NASA s Goddard Space Flight Center. Making use of a GPS signal simulator with a dual radio frequency outlet, the system includes two GPS space receivers as well as a powerful onboard navigation processor dedicated to the GPS-based guidance, navigation, and control of a satellite formation in real-time. The closed-loop system allows realistic simulations of autonomous formation flying scenarios, enabling research in the fields of tracking and orbit control strategies for a wide range of applications. A sample scenario has been set up where the autonomous transition of a satellite formation from an initial along-track separation of 800 m to a final distance of 100 m has been demonstrated. As a result, a typical control accuracy of about 5 m has been achieved which proves the applicability of autonomous formation flying techniques to formations of satellites as close as 50 m.

Radiation Hardness Assurance (RHA) Guideline

NASA Technical Reports Server (NTRS)

Campola, Michael J.

2016-01-01

Radiation Hardness Assurance (RHA) consists of all activities undertaken to ensure that the electronics and materials of a space system perform to their design specifications after exposure to the mission space environment. The subset of interests for NEPP and the REAG, are EEE parts. It is important to register that all of these undertakings are in a feedback loop and require constant iteration and updating throughout the mission life. More detail can be found in the reference materials on applicable test data for usage on parts.

Ultralow-intensity magneto-optical and mechanical effects in metal nanocolloids.

PubMed

Moocarme, M; Domínguez-Juárez, J L; Vuong, L T

2014-03-12

Magneto-plasmonics is a designation generally associated with ferromagnetic-plasmonic materials because such optical responses from nonmagnetic materials alone are considered weak. Here, we show that there exists a switching transition between linear and nonlinear magneto-optical behaviors in noble-metal nanocolloids that is observable at ultralow illumination intensities and direct current magnetic fields. The response is attributed to polarization-dependent nonzero-time-averaged plasmonic loops, vortex power flows, and nanoparticle magnetization. This work identifies significant mechanical effects that subsequently exist via magnetic-dipole interactions.

Unmanned Aircraft Systems Human-in-the-Loop Controller and Pilot Acceptability Study: Collision Avoidance, Self-Separation, and Alerting Times (CASSAT)

NASA Technical Reports Server (NTRS)

Comstock, James R., Jr.; Ghatas, Rania W.; Vincent, Michael J.; Consiglio, Maria C.; Munoz, Cesar; Chamberlain, James P.; Volk, Paul; Arthur, Keith E.

2016-01-01

The Federal Aviation Administration (FAA) has been mandated by the Congressional funding bill of 2012 to open the National Airspace System (NAS) to Unmanned Aircraft Systems (UAS). With the growing use of unmanned systems, NASA has established a multi-center "UAS Integration in the NAS" Project, in collaboration with the FAA and industry, and is guiding its research efforts to look at and examine crucial safety concerns regarding the integration of UAS into the NAS. Key research efforts are addressing requirements for detect-and-avoid (DAA), self-separation (SS), and collision avoidance (CA) technologies. In one of a series of human-in-the-loop experiments, NASA Langley Research Center set up a study known as Collision Avoidance, Self-Separation, and Alerting Times (CASSAT). The first phase assessed active air traffic controller interactions with DAA systems and the second phase examined reactions to the DAA system and displays by UAS Pilots at a simulated ground control station (GCS). Analyses of the test results from Phase I and Phase II are presented in this paper. Results from the CASSAT study and previous human-in-the-loop experiments will play a crucial role in the FAA's establishment of rules, regulations, and procedures to safely, efficiently, and effectively integrate UAS into the NAS.

An investigation into closed-loop treatment of neurological disorders based on sensing mitochondrial dysfunction.

PubMed

Adams, Scott D; Kouzani, Abbas Z; Tye, Susannah J; Bennet, Kevin E; Berk, Michael

2018-02-13

Dynamic feedback based closed-loop medical devices offer a number of advantages for treatment of heterogeneous neurological conditions. Closed-loop devices integrate a level of neurobiological feedback, which allows for real-time adjustments to be made with the overarching aim of improving treatment efficacy and minimizing risks for adverse events. One target which has not been extensively explored as a potential feedback component in closed-loop therapies is mitochondrial function. Several neurodegenerative and psychiatric disorders including Parkinson's disease, Major Depressive disorder and Bipolar disorder have been linked to perturbations in the mitochondrial respiratory chain. This paper investigates the potential to monitor this mitochondrial function as a method of feedback for closed-loop neuromodulation treatments. A generic model of the closed-loop treatment is developed to describe the high-level functions of any system designed to control neural function based on mitochondrial response to stimulation, simplifying comparison and future meta-analysis. This model has four key functional components including: a sensor, signal manipulator, controller and effector. Each of these components are described and several potential technologies for each are investigated. While some of these candidate technologies are quite mature, there are still technological gaps remaining. The field of closed-loop medical devices is rapidly evolving, and whilst there is a lot of interest in this area, widespread adoption has not yet been achieved due to several remaining technological hurdles. However, the significant therapeutic benefits offered by this technology mean that this will be an active area for research for years to come.

Feasibility of outpatient fully integrated closed-loop control: first studies of wearable artificial pancreas.

PubMed

Kovatchev, Boris P; Renard, Eric; Cobelli, Claudio; Zisser, Howard C; Keith-Hynes, Patrick; Anderson, Stacey M; Brown, Sue A; Chernavvsky, Daniel R; Breton, Marc D; Farret, Anne; Pelletier, Marie-Josée; Place, Jérôme; Bruttomesso, Daniela; Del Favero, Simone; Visentin, Roberto; Filippi, Alessio; Scotton, Rachele; Avogaro, Angelo; Doyle, Francis J

2013-07-01

To evaluate the feasibility of a wearable artificial pancreas system, the Diabetes Assistant (DiAs), which uses a smart phone as a closed-loop control platform. Twenty patients with type 1 diabetes were enrolled at the Universities of Padova, Montpellier, and Virginia and at Sansum Diabetes Research Institute. Each trial continued for 42 h. The United States studies were conducted entirely in outpatient setting (e.g., hotel or guest house); studies in Italy and France were hybrid hospital-hotel admissions. A continuous glucose monitoring/pump system (Dexcom Seven Plus/Omnipod) was placed on the subject and was connected to DiAs. The patient operated the system via the DiAs user interface in open-loop mode (first 14 h of study), switching to closed-loop for the remaining 28 h. Study personnel monitored remotely via 3G or WiFi connection to DiAs and were available on site for assistance. The total duration of proper system communication functioning was 807.5 h (274 h in open-loop and 533.5 h in closed-loop), which represented 97.7% of the total possible time from admission to discharge. This exceeded the predetermined primary end point of 80% system functionality. This study demonstrated that a contemporary smart phone is capable of running outpatient closed-loop control and introduced a prototype system (DiAs) for further investigation. Following this proof of concept, future steps should include equipping insulin pumps and sensors with wireless capabilities, as well as studies focusing on control efficacy and patient-oriented clinical outcomes.

Fabrication and processing of next-generation oxygen carrier materials for chemical looping combustion

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

Nadarajah, Arunan

Among numerous methods of controlling the global warming effect, Chemical Looping Combustion is known to be the most viable option currently. A key factor to a successful chemical looping process is the presence of highly effective oxygen carriers that enable fuel combustion by going through oxidation and reduction in the presence of air and fuel respectively. In this study, CaMnO 3-δ was used as the base material and doped on the A-site (Sr or La) and B-site (Fe, Ti, Zn and Al) by 10 mol % of dopants. Solid state reaction followed by mechanical extrusion (optimized paste formula) was usedmore » as the preparation method A series of novel doped perovskite-type oxygen carrier particles (Ca xLa (Or Sa) 1-x Mn 1-yByO 3-δ (B-site = Fe, Ti, Al, or Zr)) were synthesized by the proposed extrusion formula. The produced samples were characterized with XRD, SEM, BET and TGA techniques. According to the results obtained from TGA analysis, the oxygen capacity of the samples ranged between 1.2 for CLMZ and 1.75 for CSMF. Reactivity and oxygen uncoupling behaviors of the prepared samples were also evaluated using a fluidized bed chemical looping reactor using methane as the fuel at four different temperatures (800, 850, 900, 950 °C). All of the oxygen carriers showed oxygen uncoupling behavior and they were able to capture and release oxygen. Mass-based conversion of the perovskites was calculated and temperature increase proved to increase the mass-based conversion rate in all of the samples under study. Gas yield was calculated at 950 °C as well, and results showed that CLMZ, CM and CSMF showed 100% gas yields and CLMF and CSMZ showed approximately 85% yield in fluidized bed reactor, which is a high and acceptable quantity. Based on extended reactor tests the modified calcium manganese perovskite structures (CSMF) can be a good candidate for future pilot tests.« less

Researching for sustained translation from site cluster permeability into building courtyard and interior atrium

NASA Astrophysics Data System (ADS)

Teddy Badai Samodra, FX; Defiana, Ima; Setyawan, Wahyu

2018-03-01

Many previous types of research have discussed the permeability of site cluster. Because of interaction and interconnected attribute, it will be better that there is its translation into lower context such as building and interior scale. In this paper, the sustainability design performance of both similar designs of courtyard and atrium are investigated continuing the recommendation of site space permeability. By researching related literature review and study through Ecotect Analysis and Ansys Fluent simulations, the pattern transformation and optimum courtyard and atrium design could comply the requirement. The results highlighted that the air movement from the site could be translated at the minimum of 50% higher to the building and indoor environment. Thus, it has potency for energy efficiency when grid, loop, and cul-de-sac site clusters, with 25% of ground coverage, have connectivity with building courtyard compared to the atrium. Energy saving is higher when using low thermal transmittance of transparent material and its lower area percentages for the courtyard walls. In general, it was more energy efficient option as part of a low rise building, while the courtyard building performed better with increasing irregular building height more than 90% of the difference.

Neuromuscular control and ankle instability.

PubMed

Gutierrez, Gregory M; Kaminski, Thomas W; Douex, Al T

2009-04-01

Lateral ankle sprains (LAS) are common injuries in athletics and daily activity. Although most are resolved with conservative treatment, others develop chronic ankle instability (AI)-a condition associated with persistent pain, weakness, and instability-both mechanical (such as ligamentous laxity) and functional (neuromuscular impairment with or without mechanical laxity). The predominant theory in AI is one of articular deafferentation from the injury, affecting closed-loop (feedback/reflexive) neuromuscular control, but recent research has called that theory into question. A considerable amount of attention has been directed toward understanding the underlying causes of this pathology; however, little is known concerning the neuromuscular mechanisms behind the development of AI. The purpose of this review is to summarize the available literature on neuromuscular control in uninjured individuals and individuals with AI. Based on available research and reasonable speculation, it seems that open-loop (feedforward/anticipatory) neuromuscular control may be more important for the maintenance of dynamic joint stability than closed-loop control systems that rely primarily on proprioception. Therefore, incorporating perturbation activities into patient rehabilitation schemes may be of some benefit in enhancing these open-loop control mechanisms. Despite the amount of research conducted in this area, analysis of individuals with AI during dynamic conditions is limited. Future work should aim to evaluate dynamic perturbations in individuals with AI, as well as subjects who have a history of at least one LAS and never experienced recurrent symptoms. These potential findings may help elucidate some compensatory mechanisms, or more appropriate neuromuscular control strategies after an LAS event, thus laying the groundwork for future intervention studies that can attempt to reduce the incidence and severity of acute and chronic lateral ankle injury.

Influential factors of red-light running at signalized intersection and prediction using a rare events logistic regression model.

PubMed

Ren, Yilong; Wang, Yunpeng; Wu, Xinkai; Yu, Guizhen; Ding, Chuan

2016-10-01

Red light running (RLR) has become a major safety concern at signalized intersection. To prevent RLR related crashes, it is critical to identify the factors that significantly impact the drivers' behaviors of RLR, and to predict potential RLR in real time. In this research, 9-month's RLR events extracted from high-resolution traffic data collected by loop detectors from three signalized intersections were applied to identify the factors that significantly affect RLR behaviors. The data analysis indicated that occupancy time, time gap, used yellow time, time left to yellow start, whether the preceding vehicle runs through the intersection during yellow, and whether there is a vehicle passing through the intersection on the adjacent lane were significantly factors for RLR behaviors. Furthermore, due to the rare events nature of RLR, a modified rare events logistic regression model was developed for RLR prediction. The rare events logistic regression method has been applied in many fields for rare events studies and shows impressive performance, but so far none of previous research has applied this method to study RLR. The results showed that the rare events logistic regression model performed significantly better than the standard logistic regression model. More importantly, the proposed RLR prediction method is purely based on loop detector data collected from a single advance loop detector located 400 feet away from stop-bar. This brings great potential for future field applications of the proposed method since loops have been widely implemented in many intersections and can collect data in real time. This research is expected to contribute to the improvement of intersection safety significantly. Copyright © 2016 Elsevier Ltd. All rights reserved.

Conceptual design of a thermalhydraulic loop for multiple test geometries at supercritical conditions named Supercritical Phenomena Experimental Test Apparatus (SPETA)

NASA Astrophysics Data System (ADS)

Adenariwo, Adepoju

The efficiency of nuclear reactors can be improved by increasing the operating pressure of current nuclear reactors. Current CANDU-type nuclear reactors use heavy water as coolant at an outlet pressure of up to 11.5 MPa. Conceptual SuperCritical Water Reactors (SCWRs) will operate at a higher coolant outlet pressure of 25 MPa. Supercritical water technology has been used in advanced coal plants and its application proves promising to be employed in nuclear reactors. To better understand how supercritical water technology can be applied in nuclear power plants, supercritical water loops are used to study the heat transfer phenomena as it applies to CANDU-type reactors. A conceptual design of a loop known as the Supercritical Phenomena Experimental Apparatus (SPETA) has been done. This loop has been designed to fit in a 9 m by 2 m by 2.8 m enclosure that will be installed at the University of Ontario Institute of Technology Energy Research Laboratory. The loop include components to safely start up and shut down various test sections, produce a heat source to the test section, and to remove reject heat. It is expected that loop will be able to investigate the behaviour of supercritical water in various geometries including bare tubes, annulus tubes, and multi-element-type bundles. The experimental geometries are designed to match the fluid properties of Canadian SCWR fuel channel designs so that they are representative of a practical application of supercritical water technology in nuclear plants. This loop will investigate various test section orientations which are the horizontal, vertical, and inclined to investigate buoyancy effects. Frictional pressure drop effects and satisfactory methods of estimating hydraulic resistances in supercritical fluid shall also be estimated with the loop. Operating limits for SPETA have been established to be able to capture the important heat transfer phenomena at supercritical conditions. Heat balance and flow calculations have been done to appropriately size components in the loop. Sensitivity analysis has been done to find the optimum design for the loop.

Use of electrochromic materials in adaptive optics.

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

Kammler, Daniel R.; Sweatt, William C.; Verley, Jason C.

Electrochromic (EC) materials are used in 'smart' windows that can be darkened by applying a voltage across an EC stack on the window. The associated change in refractive index (n) in the EC materials might allow their use in tunable or temperature-insensitive Fabry-Perot filters and transmissive-spatial-light-modulators (SLMs). The authors are conducting a preliminary evaluation of these materials in many applications, including target-in-the-loop systems. Data on tungsten oxide, WO{sub 3}, the workhorse EC material, indicate that it's possible to achieve modest changes in n with only slight increases in absorption between the visible and {approx}10 {micro}m. This might enable construction ofmore » a tunable Fabry-Perot filter consisting of an active EC layer (e.g. WO{sub 3}) and a proton conductor (e.g.Ta{sub 2}O{sub 5}) sandwiched between two gold electrodes. A SLM might be produced by replacing the gold with a transparent conductor (e.g. ITO). This SLM would allow broad-band operation like a micromirror array. Since it's a transmission element, simple optical designs like those in liquid-crystal systems would be possible. Our team has fabricated EC stacks and characterized their switching speed and optical properties (n, k). We plan to study the interplay between process parameters, film properties, and performance characteristics associated with the FP-filter and then extend what we learn to SLMs. Our goals are to understand whether the changes in absorption associated with changes in n are acceptable, and whether it's possible to design an EC-stack that's fast enough to be interesting. We'll present our preliminary findings regarding the potential viability of EC materials for target-in-the-loop applications.« less

Spacecraft attitude control using a smart control system

NASA Technical Reports Server (NTRS)

Buckley, Brian; Wheatcraft, Louis

1992-01-01

Traditionally, spacecraft attitude control has been implemented using control loops written in native code for a space hardened processor. The Naval Research Lab has taken this approach during the development of the Attitude Control Electronics (ACE) package. After the system was developed and delivered, NRL decided to explore alternate technologies to accomplish this same task more efficiently. The approach taken by NRL was to implement the ACE control loops using systems technologies. The purpose of this effort was to: (1) research capabilities required of an expert system in processing a classic closed-loop control algorithm; (2) research the development environment required to design and test an embedded expert systems environment; (3) research the complexity of design and development of expert systems versus a conventional approach; and (4) test the resulting systems against the flight acceptance test software for both response and accuracy. Two expert systems were selected to implement the control loops. Criteria used for the selection of the expert systems included that they had to run in both embedded systems and ground based environments. Using two different expert systems allowed a comparison of the real-time capabilities, inferencing capabilities, and the ground-based development environment. The two expert systems chosen for the evaluation were Spacecraft Command Language (SCL), and NEXTPERT Object. SCL is a smart control system produced for the NRL by Interface and Control Systems (ICS). SCL was developed to be used for real-time command, control, and monitoring of a new generation of spacecraft. NEXPERT Object is a commercially available product developed by Neuron Data. Results of the effort were evaluated using the ACE test bed. The ACE test bed had been developed and used to test the original flight hardware and software using simulators and flight-like interfaces. The test bed was used for testing the expert systems in a 'near-flight' environment. The technical approach, the system architecture, the development environments, knowledge base development, and results of this effort are detailed.

The accomplishments of lithium target and test facility validation activities in the IFMIF/EVEDA phase

NASA Astrophysics Data System (ADS)

Arbeiter, Frederik; Baluc, Nadine; Favuzza, Paolo; Gröschel, Friedrich; Heidinger, Roland; Ibarra, Angel; Knaster, Juan; Kanemura, Takuji; Kondo, Hiroo; Massaut, Vincent; Saverio Nitti, Francesco; Miccichè, Gioacchino; O'hira, Shigeru; Rapisarda, David; Sugimoto, Masayoshi; Wakai, Eiichi; Yokomine, Takehiko

2018-01-01

As part of the engineering validation and engineering design activities (EVEDA) phase for the international fusion materials irradiation facility IFMIF, major elements of a lithium target facility and the test facility were designed, prototyped and validated. For the lithium target facility, the EVEDA lithium test loop was built at JAEA and used to test the stability (waves and long term) of the lithium flow in the target, work out the startup procedures, and test lithium purification and analysis. It was confirmed by experiments in the Lifus 6 plant at ENEA that lithium corrosion on ferritic martensitic steels is acceptably low. Furthermore, complex remote handling procedures for the remote maintenance of the target in the test cell environment were successfully practiced. For the test facility, two variants of a high flux test module were prototyped and tested in helium loops, demonstrating their good capabilities of maintaining the material specimens at the desired temperature with a low temperature spread. Irradiation tests were performed for heated specimen capsules and irradiation instrumentation in the BR2 reactor at SCK-CEN. The small specimen test technique, essential for obtaining material test results with limited irradiation volume, was advanced by evaluating specimen shape and test technique influences.