Sample records for stacked column consisting

  1. Analysis of low-pass filters consisting of multiple stacked FSS's of different periodicities with applications in the submillimeter radioastronomy. (United States)

    Aroudaki, H.; Hansen, V.; Gemund, H.-P.; Kreysa, E.


    A spectral domain approach is presented which allows multiple stacked frequency selective screens (FSS's) to be investigated. The analysis is exact if all arrays have the same periodicity or if a unit cell of finite extent valid for the whole FSS can be defined. Further, this approach can be used as a very efficient approximation for analyzing low-pass filters applied in radioastronomy and consisting of arrays with different periodicities, as long as the unit cell dimensions and the separation between the arrays are small small compared to the wavelength at the operating frequency. Numerical results for several FSS configurations are presented and compared with measured values.

  2. Commissioning of the scatter component of a Compton camera consisting of a stack of Si strip detectors

    Energy Technology Data Exchange (ETDEWEB)

    Liprandi, S.; Marinsek, T.; Bortfeldt, J.; Lang, C.; Lutter, R.; Dedes, G.; Parodi, K.; Thirolf, P.G. [LMU Munich, Garching (Germany); Aldawood, S. [LMU Munich, Garching (Germany); King Saud University, Riyadh (Saudi Arabia); Maier, L.; Gernhaeuser, R. [TU Munich, Garching (Germany); Kolff, H. van der [LMU Munich, Garching (Germany); TU Delft (Netherlands); Castelhano, I. [LMU Munich, Garching (Germany); University of Lisbon, Lisbon (Portugal); Schaart, D.R. [TU Delft (Netherlands)


    At LMU Munich in Garching a Compton camera is presently being developed aiming at the range verification of proton (or ion) beams for hadron therapy via imaging of prompt γ rays from nuclear reactions in the tissue. The poster presentation focuses on the characterization of the scatter component of the Compton camera, consisting of a stack of six double-sided Si strip detectors (50 x 50 mm{sup 2}, 0.5 mm thick, 128 strips/side). The overall 1536 electronics channels are processed by a readout system based on the GASSIPLEX ASIC chip, feeding into a VME-based data acquisition system. The status of the offline and online characterization studies is presented.

  3. OpenStack Swift as Multi-Region Eventual Consistency Storage for ownCloud Primary Storage

    CERN Multimedia

    CERN. Geneva


    As more users adopt AARNet’s CloudStor Plus offering within Australia, interim solutions deployed to overcome failures of various distributed replicated storage technologies haven’t kept pace with the growth in data volume. AARNet’s original design goal of user proximal data storage, combined with national and even international data replication for redundancy reasons continues to be a key driver for design choices. AARNet’s national network is over 90ms from end to end, and accommodating this has been a key issue with numerous software solutions, hindering attempts to provide both original design goals in a reliable real-time manner. With the addition of features to the ownCloud software allowing primary data storage on OpenStack Swift, AARNet has chosen to deploy Swift in a nation spanning multi-region ring to take advantage of Swift’s eventual consistency capabilities and the local region quorum functionality for fast writes. The scaling capability of Swift resolves the twin problems of geogr...

  4. Determination of hexavalent chromium concentration in industrial waste incinerator stack gas by using a modified ion chromatography with post-column derivatization method. (United States)

    Miyake, Yuichi; Tokumura, Masahiro; Iwazaki, Yuta; Wang, Qi; Amagai, Takashi; Horii, Yuichi; Otsuka, Hideyuki; Tanikawa, Noboru; Kobayashi, Takeshi; Oguchi, Masahiro


    An ion chromatography with post-column derivatization with 1,5-diphenylcarbazide (IC-DPC) analytical method was modified to enable measurement of trace-level hexavalent chromium (Cr(VI)) in air. One of the difficulties in determining trace levels of Cr(VI) in air with conventional IC-DPC methods is co-elution of the solvent and ion peaks due to high concentrations of ionic compounds in the extract. However, by using gradient elution rather than isocratic elution we were able to fully resolve the Cr(VI) ion peak from the solvent peak without the need for diluting the extract, which would have reduced the minimum quantifiable level of the method. With this method, we were able to detect Cr(VI) in air at concentrations of 5.3ng/m 3 (assuming a sampling volume of 1m 3 and a final solution volume of 10mL). Recovery tests at three different concentrations of Cr(VI) (50, 250, 1000ng) were performed with or without fly ash; recovery rates at all the concentrations of Cr(VI), with or without fly ash, ranged from 68% to 110% (mean±relative standard deviation, 96%±11%), and there were no differences in recovery rates with respect to the presence or absence of fly ash. Finally, we used the developed method to determine the concentration of Cr(VI) in stack gases collected from eight industrial waste incinerators located in Japan. The concentration of Cr(VI) in the stack gases ranged from below the method quantification limit to 3100ng/m 3 . The highest concentrations of Cr(VI) detected in the stack gases were two to three orders of magnitude higher than that in ambient air in Japan. Copyright © 2017 Elsevier B.V. All rights reserved.

  5. Insights into head-column field-amplified sample stacking: Part II. Study of the behavior of the electrophoretic system after electrokinetic injection of cationic compounds across a short water plug

    Czech Academy of Sciences Publication Activity Database

    Šesták, Jozef; Thormann, W.


    Roč. 1512, AUG (2017), s. 124-132 ISSN 0021-9673 Institutional support: RVO:68081715 Keywords : head- column field-amplified sample stacking * capillary electrophoresis * water plug Subject RIV: CB - Analytical Chemistry, Separation OBOR OECD: Analytical chemistry Impact factor: 3.981, year: 2016

  6. Design and performance of a passive dosimeter consisting of a stack of photostimulable phosphor (PSP) imaging plates (IP) based on BaF(Br, I):Eu2+

    International Nuclear Information System (INIS)

    Jean-Paul Negre


    This manuscript presents an original concept of passive, lightweight, and compact dosimeter based on a stack of BaFBr:Eu 2+ photostimulable phosphor plates (Image Plate) alternating with high-Z metal screens. It describes the manufacture and the method to calibrate the dosimeter. This method consists in using a Co 60 standard source and Monte Carlo N-Particle codes (MCNPX/MCNP5) to apply them to a large area of radiation energies, such as quasi mono-energetic radiation (Gamma rays decay of radioactive isotope, X-ray fluorescence), or continuous radiation spectra (Bremsstrahlung radiation, synchrotron light source). The measurement recurrence in the stack of couples 'metallic foil / IP' ensures consistency measurements, determines the threshold depth of electronic equilibrium (depending on the radiation energy) and allows us to infer the absolute dose in air (Kerma). The depth-dose curve in the stack and transmission measurements provide an estimate of the effective energy of incident radiations, report the presence of parasite scattered radiations and allow us to discriminate the nature of ionizing particles. The 2D features of the device are used to characterize the ballistic fate of charged particles in material thickness, which is of great interest with narrow particles beams. This dosimeter has remarkable advantages over other passive dosimeters, including a dynamic range larger than 10 7 of linear photon dose detection from less than 0.5 μGy and up to several Gy for radiation energies between a few tens of keV and more than 10 MeV (20 MeV with Bremsstrahlung X-ray spectra). This concept originality consists in almost immediately getting the measurement results after an exposure and a single pass reading of the dosimeter. It can respond positively to most of the usual needs in radiation metrology: personal or environmental dosimetry (radiation protection); Controls / characterization / mapping around materials and emitting ionizing radiation devices

  7. Insights into head-column field-amplified sample stacking: Part II. Study of the behavior of the electrophoretic system after electrokinetic injection of cationic compounds across a short water plug. (United States)

    Šesták, Jozef; Thormann, Wolfgang


    Part I on head-column field-amplified sample stacking comprised a detailed study of the electrokinetic injection of a weak base across a short water plug into a phosphate buffer at low pH. The water plug is converted into a low conductive acidic zone and cationic analytes become stacked at the interface between this and a newly formed phosphoric acid zone. The fundamentals of electrokinetic processes occurring thereafter were studied experimentally and with computer simulation and are presented as part II. The configuration analyzed represents a discontinuous buffer system. Computer simulation revealed that the phosphoric acid zone at the plug-buffer interface becomes converted into a migrating phosphate buffer plug which corresponds to the cationically migrating system zone of the phosphate buffer system. Its mobility is higher than that of the analytes such that they migrate behind the system zone in a phosphate buffer comparable to the applied background electrolyte. The temporal behaviour of the current and the conductivity across the water plug were monitored and found to reflect the changes in the low conductivity plug. Determination of the buffer flow in the capillary revealed increased pumping caused by the mismatch of electroosmosis within the low conductivity plug and the buffer. This effect becomes elevated with increasing water plug length. For plug lengths up to 1% of the total column length the flow quickly drops to the electroosmotic flow of the buffer and simulations with experimentally determined current and flow values predict negligible band dispersion and no loss of resolution for both low and large molecular mass components. Copyright © 2017 Elsevier B.V. All rights reserved.

  8. Highly sensitive analysis of nucleic acids using capillary gel electrophoresis with ultraviolet detection based on the combination of matrix field-amplified and head-column field-amplified stacking injection. (United States)

    Lian, Dong-Sheng; Zhao, Shu-Jin


    To develop a highly sensitive method for analyzing nucleic acids using capillary gel electrophoresis with ultraviolet detection (CGE-UV), we combined matrix field-amplified with head-column field-amplified stacking injection (C-FASI) to employ the advantages of two methods. Without diminishing the resolution, a limit of detection of 0.13 ng/ml (signal/noise=3) in a 300,000-fold diluted sample was obtained, the sensitivity is 102,308 times higher than that achieved with normal pressure injection, 3077 times that with normal electrokinetic injection, 154 times that with pressure field-amplified sample stacking injection, and 31 times that with matrix field-amplified stacking injection. After establishing the method, we tested the detection of a φX174-Hae III digest DNA product without purification and with a high ionic strength. At the lowest dilution of 5000-fold, sample at a concentration of 10 ng/ml was enriched and detected. The relative standard deviations for migration time and peak area (n=3) were 0.03-1.15 and 0.72-6.42, respectively. To further validate C-FASI was applicable for real sample, a 400 bp PCR product without purification was directly detected with a limit of detection at the concentration of 6000-fold dilution (signal/noise=3), The relative standard deviations for migration time and peak area (n=6) were 0.44 and 4.8, respectively. These results indicated that C-FASI had good qualitative and quantitative detection abilities and CGE-UV based on C-FASI is easy to perform, practical, highly-sensitive and robust for nucleic acid detection, which makes it a highly valuable tool for genetic diagnostics based on nucleic acid analysis. Copyright © 2014 Elsevier B.V. All rights reserved.

  9. High Ice Water Content at Low Radar Reflectivity near Deep Convection. Part I ; Consistency of In Situ and Remote-Sensing Observations with Stratiform Rain Column Simulations (United States)

    Fridlind, A. M.; Ackerman, A. S.; Grandin, A.; Dezitter, F.; Weber, M.; Strapp, J. W.; Korolev, A. V.; Williams, C. R.


    Occurrences of jet engine power loss and damage have been associated with flight through fully glaciated deep convection at -10 to -50 degrees Centigrade. Power loss events commonly occur during flight through radar reflectivity (Zeta (sub e)) less than 20-30 decibels relative to Zeta (dBZ - radar returns) and no more than moderate turbulence, often overlying moderate to heavy rain near the surface. During 2010-2012, Airbus carried out flight tests seeking to characterize the highest ice water content (IWC) in such low-radar-reflectivity regions of large, cold-topped storm systems in the vicinity of Cayenne, Darwin, and Santiago. Within the highest IWC regions encountered, at typical sampling elevations (circa 11 kilometers), the measured ice size distributions exhibit a notably narrow concentration of mass over area-equivalent diameters of 100-500 micrometers. Given substantial and poorly quantified measurement uncertainties, here we evaluate the consistency of the Airbus in situ measurements with ground-based profiling radar observations obtained under quasi-steady, heavy stratiform rain conditions in one of the Airbus-sampled locations. We find that profiler-observed radar reflectivities and mean Doppler velocities at Airbus sampling temperatures are generally consistent with those calculated from in situ size-distribution measurements. We also find that column simulations using the in situ size distributions as an upper boundary condition are generally consistent with observed profiles of radar reflectivity (Ze), mean Doppler velocity (MDV), and retrieved rain rate. The results of these consistency checks motivate an examination of the microphysical pathways that could be responsible for the observed size-distribution features in Ackerman et al. (2015).

  10. Algebraic stacks

    Indian Academy of Sciences (India)

    generally, any fiber product) is not uniquely defined: it is only defined up to unique isomorphism. ..... Fiber product. Given two morphisms f1 : F1 ! G, f2 : F2 ! G, we define a new stack. F1 آG F2 (with projections to F1 and F2) as follows. The objects are triples ًX1; X2; ق ..... In fact, any Artin stack F can be defined in this fashion.

  11. Algebraic stacks

    Indian Academy of Sciences (India)

    truct the 'moduli stack', that captures all the information that we would like in a fine moduli space. ..... the fine moduli space), it has the property that for any family W of vector bundles (i.e. W is a vector bundle over B ...... the etale topology is finer: V is a 'small enough open subset' because the square root can be defined on it.

  12. Geophysical validation and long-term consistency between GOME-2/MetOp-A total ozone column and measurements from the sensors GOME/ERS-2, SCIAMACHY/ENVISAT and OMI/Aura

    Directory of Open Access Journals (Sweden)

    M. E. Koukouli


    Full Text Available The main aim of the paper is to assess the consistency of five years of Global Ozone Monitoring Experiment-2/Metop-A [GOME-2] total ozone columns and the long-term total ozone satellite monitoring database already in existence through an extensive inter-comparison and validation exercise using as reference Brewer and Dobson ground-based measurements. The behaviour of the GOME-2 measurements is being weighed against that of GOME (1995–2011, Ozone Monitoring Experiment [OMI] (since 2004 and the Scanning Imaging Absorption spectroMeter for Atmospheric CartograpHY [SCIAMACHY] (since 2002 total ozone column products. Over the background truth of the ground-based measurements, the total ozone columns are inter-evaluated using a suite of established validation techniques; the GOME-2 time series follow the same patterns as those observed by the other satellite sensors. In particular, on average, GOME-2 data underestimate GOME data by about 0.80%, and underestimate SCIAMACHY data by 0.37% with no seasonal dependence of the differences between GOME-2, GOME and SCIAMACHY. The latter is expected since the three datasets are based on similar DOAS algorithms. This underestimation of GOME-2 is within the uncertainty of the reference data used in the comparisons. Compared to the OMI sensor, on average GOME-2 data underestimate OMI_DOAS (collection 3 data by 1.28%, without any significant seasonal dependence of the differences between them. The lack of seasonality might be expected since both the GOME data processor [GDP] 4.4 and OMI_DOAS are DOAS-type algorithms and both consider the variability of the stratospheric temperatures in their retrievals. Compared to the OMI_TOMS (collection 3 data, no bias was found. We hence conclude that the GOME-2 total ozone columns are well suitable to continue the long-term global total ozone record with the accuracy needed for climate monitoring studies.

  13. Mush Column Magma Chambers (United States)

    Marsh, B. D.


    of the system, coupled with these processes, define the fundamental compositional and dynamic diversity of the Mush Column. In some ways it functions like a complex musical instrument. Entrainment, transport, and sorting of cumulate crystals as a function of repose time and the local flux intensity also contribute to the basic compositional diversity of the system. In the Ferrar dolerite system, about 104 km3 of dolerite is distributed throughout a fir-tree like stack of 4 or 5 extensive 300-750 m thick sills. The lowest sill contains a vast tongue of entrained orthopyroxene (opx) cumulates emplaced with the sill itself. The bulk sill composition varies from 20 pc MgO in the tongue center to 7 pc in the leading tip and margins of the sill, which itself defines the compositional spectrum of the whole complex and is remarkably similar to that exhibited by Hawaii. Relative sorting of large (1-50 mm) opx and small (1-3 mm) plagioclase due to kinetic sieving in the tongue produces pervasive anorthosite stringers. Through local ponding this has culminated in the formation of a small, well-formed layered intrusion consisting of alternating layers of orthopyroxenite and anorthosite. Upwards in the system the sills become progressively depleted in MgO and temporally and spatially contiguous flood basalts are low MgO tholeiites with no sign of opx cumulates. The size, extent, number of sills, and the internal structure of individual sills suggest a rhythm of injection similar to that of volcanic episodes. The continued horizontal stretching of a system of this type would lead to processes as recorded by ophiolites, and the repeated injection into a single reservoir would undoubtedly lead to a massive layered intrusion or to a series of high-level nested plutons.

  14. Sport stacking motor intervention programme for children with ...

    African Journals Online (AJOL)

    The purpose of this study was to explore sport stacking as an alternative intervention approach with typically developing children and in addition to improve DCD. Sport stacking consists of participants stacking and unstacking 12 specially designed plastic cups in predetermined sequences in as little time as possible.

  15. Gravity Effects on the Free Vibration of a Graphite Column

    International Nuclear Information System (INIS)

    Ki, Dong-Ok; Kim, Jong-Bum; Park, Keun-Bae; Lee, Won-Jae


    The gravity effects on the free vibration of a graphite column are studied. Graphite block is a key component of a HTGR (High Temperature Gas Cooled Reactor). The major core elements, such as the fuel blocks and neutron reflector blocks, of HTTR (High Temperature Test Reactor, Japan) and GT-MHR (Gas Turbine- Modular Helium Reactor, USA) consist of stacked hexagonal graphite blocks forming a group of columns. The vibration of the columns induced by earthquakes may lead to solid impacts between graphite blocks and structural integrity problems. The study of free vibration characteristics of the graphite block column is the first step in the core internal structure dynamic analysis. Gravity force bring a negative stiffness term to the transverse vibration analysis of heavy long column structures, and results in natural frequency reductions. Generally it is not considered in the not so tall structure cases, because the gravity term makes the analysis and design complicated. Therefore it is important to check whether the gravity effect is severe or not

  16. Deploying OpenStack

    CERN Document Server

    Pepple, Ken


    OpenStack was created with the audacious goal of being the ubiquitous software choice for building public and private cloud infrastructures. In just over a year, it's become the most talked-about project in open source. This concise book introduces OpenStack's general design and primary software components in detail, and shows you how to start using it to build cloud infrastructures. If you're a developer, technologist, or system administrator familiar with cloud offerings such as Rackspace Cloud or Amazon Web Services, Deploying OpenStack shows you how to obtain and deploy OpenStack softwar

  17. OpenStack essentials

    CERN Document Server

    Radez, Dan


    If you need to get started with OpenStack or want to learn more, then this book is your perfect companion. If you're comfortable with the Linux command line, you'll gain confidence in using OpenStack.

  18. Mastering OpenStack

    CERN Document Server

    Khedher, Omar


    This book is intended for system administrators, cloud engineers, and system architects who want to deploy a cloud based on OpenStack in a mid- to large-sized IT infrastructure. If you have a fundamental understanding of cloud computing and OpenStack and want to expand your knowledge, then this book is an excellent checkpoint to move forward.

  19. PULSE COLUMN (United States)

    Grimmett, E.S.


    This patent covers a continuous countercurrent liquidsolids contactor column having a number of contactor states each comprising a perforated plate, a layer of balls, and a downcomer tube; a liquid-pulsing piston; and a solids discharger formed of a conical section at the bottom of the column, and a tubular extension on the lowest downcomer terminating in the conical section. Between the conical section and the downcomer extension is formed a small annular opening, through which solids fall coming through the perforated plate of the lowest contactor stage. This annular opening is small enough that the pressure drop thereacross is greater than the pressure drop upward through the lowest contactor stage. (AEC)

  20. Controlling retention, selectivity and magnitude of EOF by segmented monolithic columns consisting of octadecyl and naphthyl monolithic segments--applications to RP-CEC of both neutral and charged solutes. (United States)

    Karenga, Samuel; El Rassi, Ziad


    Monolithic capillaries made of two adjoining segments each filled with a different monolith were introduced for the control and manipulation of the electroosmotic flow (EOF), retention and selectivity in reversed phase-capillary electrochromatography (RP-CEC). These columns were called segmented monolithic columns (SMCs) where one segment was filled with a naphthyl methacrylate monolith (NMM) to provide hydrophobic and π-interactions, while the other segment was filled with an octadecyl acrylate monolith (ODM) to provide solely hydrophobic interaction. The ODM segment not only provided hydrophobic interactions but also functioned as the EOF accelerator segment. The average EOF of the SMC increased linearly with increasing the fractional length of the ODM segment. The neutral SMC provided a convenient way for tuning EOF, selectivity and retention in the absence of annoying electrostatic interactions and irreversible solute adsorption. The SMCs allowed the separation of a wide range of neutral solutes including polycyclic aromatic hydrocarbons (PAHs) that are difficult to separate using conventional alkyl-bonded stationary phases. In all cases, the k' of a given solute was a linear function of the fractional length of the ODM or NMM segment in the SMCs, thus facilitating the tailoring of a given SMC to solve a given separation problem. At some ODM fractional length, the fabricated SMC allowed the separation of charged solutes such as peptides and proteins that could not otherwise be achieved on a monolithic column made from NMM as an isotropic stationary phase due to the lower EOF exhibited by this monolith. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Stack filter classifiers

    Energy Technology Data Exchange (ETDEWEB)

    Porter, Reid B [Los Alamos National Laboratory; Hush, Don [Los Alamos National Laboratory


    Just as linear models generalize the sample mean and weighted average, weighted order statistic models generalize the sample median and weighted median. This analogy can be continued informally to generalized additive modeels in the case of the mean, and Stack Filters in the case of the median. Both of these model classes have been extensively studied for signal and image processing but it is surprising to find that for pattern classification, their treatment has been significantly one sided. Generalized additive models are now a major tool in pattern classification and many different learning algorithms have been developed to fit model parameters to finite data. However Stack Filters remain largely confined to signal and image processing and learning algorithms for classification are yet to be seen. This paper is a step towards Stack Filter Classifiers and it shows that the approach is interesting from both a theoretical and a practical perspective.

  2. On Stack Reconstruction Problem

    Directory of Open Access Journals (Sweden)

    V. D. Аkeliev


    Full Text Available The paper describes analytical investigations that study relation of fuel combustion regimes with concentration values of sulphur anhydride in flue gases and acid dew point. Coefficients of convective heat transfer at internal and external surfaces of stacks have been determined in the paper. The paper reveals the possibility to reconstruct stacks while using gas discharging channel made of composite material on the basis of glass-reinforced plastic which permits to reduce thermo-stressed actions on reinforced concrete and increase volume of released gases due to practically two-fold reduction of gas-dynamic pressure losses along the pipe length.

  3. Laser pulse stacking method (United States)

    Moses, E.I.


    A laser pulse stacking method is disclosed. A problem with the prior art has been the generation of a series of laser beam pulses where the outer and inner regions of the beams are generated so as to form radially non-synchronous pulses. Such pulses thus have a non-uniform cross-sectional area with respect to the outer and inner edges of the pulses. The present invention provides a solution by combining the temporally non-uniform pulses in a stacking effect to thus provide a more uniform temporal synchronism over the beam diameter. 2 figs.

  4. An Exact Method for the Double TSP with Multiple Stacks

    DEFF Research Database (Denmark)

    Larsen, Jesper; Lusby, Richard Martin; Ehrgott, Matthias

    The double travelling salesman problem with multiple stacks (DTSPMS) is a pickup and delivery problem in which all pickups must be completed before any deliveries can be made. The problem originates from a real-life application where a 40 foot container (configured as 3 columns of 11 rows) is used...

  5. An Exact Method for the Double TSP with Multiple Stacks

    DEFF Research Database (Denmark)

    Lusby, Richard Martin; Larsen, Jesper; Ehrgott, Matthias


    The double travelling salesman problem with multiple stacks (DTSPMS) is a pickup and delivery problem in which all pickups must be completed before any deliveries can be made. The problem originates from a real-life application where a 40 foot container (configured as 3 columns of 11 rows) is used...

  6. po_stack_movie

    DEFF Research Database (Denmark)


    po_stack® er et reolsystem, hvis enkle elementer giver stor flexibilitet, variation og skulpturel virkning. Elementerne stables og forskydes frit, så reolens rum kan vendes til begge sider, være åbne eller lukkede og farvekombineres ubegrænset. Reolen kan let ombygges, udvides eller opdeles, når ...

  7. Learning SaltStack

    CERN Document Server

    Myers, Colton


    If you are a system administrator who manages multiple servers, then you know how difficult it is to keep your infrastructure in line. If you've been searching for an easier way, this book is for you. No prior experience with SaltStack is required.

  8. Energy Expenditure of Sport Stacking (United States)

    Murray, Steven R.; Udermann, Brian E.; Reineke, David M.; Battista, Rebecca A.


    Sport stacking is an activity taught in many physical education programs. The activity, although very popular, has been studied minimally, and the energy expenditure for sport stacking is unknown. Therefore, the purposes of this study were to determine the energy expenditure of sport stacking in elementary school children and to compare that value…

  9. OpenStack cloud security

    CERN Document Server

    Locati, Fabio Alessandro


    If you are an OpenStack administrator or developer, or wish to build solutions to protect your OpenStack environment, then this book is for you. Experience of Linux administration and familiarity with different OpenStack components is assumed.

  10. Dynamic Model of High Temperature PEM Fuel Cell Stack Temperature

    DEFF Research Database (Denmark)

    Andreasen, Søren Juhl; Kær, Søren Knudsen


    The present work involves the development of a model for predicting the dynamic temperature of a high temperature PEM (HTPEM) fuel cell stack. The model is developed to test different thermal control strategies before implementing them in the actual system. The test system consists of a prototype...... parts, where also the temperatures are measured. The heat balance of the system involves a fuel cell model to describe the heat added by the fuel cells when a current is drawn. Furthermore the model also predicts the temperatures, when heating the stack with external heating elements for start-up, heat...... the stack at a high stoichiometric air flow. This is possible because of the PBI fuel cell membranes used, and the very low pressure drop in the stack. The model consists of a discrete thermal model dividing the stack into three parts: inlet, middle and end and predicting the temperatures in these three...

  11. Stack Caching Using Split Data Caches

    DEFF Research Database (Denmark)

    Nielsen, Carsten; Schoeberl, Martin


    In most embedded and general purpose architectures, stack data and non-stack data is cached together, meaning that writing to or loading from the stack may expel non-stack data from the data cache. Manipulation of the stack has a different memory access pattern than that of non-stack data, showing...... higher temporal and spatial locality. We propose caching stack and non-stack data separately and develop four different stack caches that allow this separation without requiring compiler support. These are the simple, window, and prefilling with and without tag stack caches. The performance of the stack...

  12. Interface Consistency

    DEFF Research Database (Denmark)

    Staunstrup, Jørgen


    This paper proposes that Interface Consistency is an important issue for the development of modular designs. Byproviding a precise specification of component interfaces it becomes possible to check that separately developedcomponents use a common interface in a coherent matter thus avoiding a very...... significant source of design errors. Awide range of interface specifications are possible, the simplest form is a syntactical check of parameter types.However, today it is possible to do more sophisticated forms involving semantic checks....

  13. Stacks of SPS Dipole Magnets

    CERN Multimedia


    Stacks of SPS Dipole Magnets ready for installation in the tunnel. The SPS uses a separated function lattice with dipoles for bending and quadrupoles for focusing. The 6.2 m long normal conducting dipoles are of H-type with coils that are bent-up at the ends. There are two types, B1 (total of 360) and B2 (384). Both are for a maximum field of 1.8 Tesla and have the same outer dimensions (450x800 mm2 vxh) but with different gaps (B1: 39x129 mm2, B2: 52x92 mm2) tailored to the beam size. The yoke, made of 1.5 mm thick laminations, consists of an upper and a lower half joined together in the median plane once the coils have been inserted.

  14. Use of impedance tagging to monitor fuel cell stack performance (United States)

    Silva, Gregory

    Fuel cells are electrochemical device that are traditionally assembled in stacks to perform meaningful work. Monitoring the state of the stack is vitally important to ensure that it is operating efficiently and that constituent cells are not failing for one of a several common reasons including membrane dehydration, gas diffusion layer flooding, reactant starvation, and physical damage. Current state-of-the-art monitoring systems are costly and require at least one connection per cell on the stack, which introduces reliability concerns for stacks consisting of hundreds of cells. This thesis presents a novel approach for diagnosing problems in a fuel cell stack that attempts to reduce the cost and complexity of monitoring cells in a stack. The proposed solution modifies the electrochemical impedance spectroscopy (EIS) response of each cell in the stack by connecting an electrical tag in parallel with each cell. This approach allows the EIS response of the entire stack to identify and locate problems in the stack. Capacitors were chosen as tags because they do not interfere with normal stack operation and because they can generate distinct stack EIS responses. An experiment was performed in the Center for Automation Technologies an Systems (CATS) fuel cell laboratory at Rensselaer Polytechnic Institute (RPI) to perform EIS measurements on a single cell with and without capacitor tags to investigate the proposed solution. The EIS data collected from this experiment was used to create a fuel cell model to investigate the proposed solution under ideal conditions. This thesis found that, although the concept shows some promise in simulations, significant obstacles to implementing the proposed solution. Observed EIS response when the capacitor tags were connected did not match the expected EIS response. Constraints on the capacitor tags found by the model impose significant manufacturing challenges to the proposed solution. Further development of the proposed solution is

  15. Passive stack ventilation

    Energy Technology Data Exchange (ETDEWEB)

    Palmer, J.; Parkins, L.; Shaw, P.; Watkins, R. [Databuild, Birmingham (United Kingdom)


    The adequate ventilation of houses is essential for both the occupants and the building fabric. As air-tightness standards increase, background infiltration levels decrease and extra ventilation has to be designed into the building. Passive stack ventilation has many advantages - particularly when employed in low cost housing schemes -but it is essential that it performs satisfactorily. This paper give the results from monitoring two passive stack ventilation schemes. One scheme was a retrofit into refurbished local authority houses in which a package of energy efficiency measures had been taken and condensation had been a problem. The other series of tests were conducted on a new installation in a Housing Association development. Nine houses were monitored each of which had at least two passive vents. The results show air flow rates by the passive ducts equivalent to approximately 1 room air change per hour. The air flow in the ducts was influenced by both, internal to external temperature difference and wind speed and direction. (author)

  16. Asymmetric Flexible Supercapacitor Stack

    Directory of Open Access Journals (Sweden)

    Leela Mohana Reddy A


    Full Text Available AbstractElectrical double layer supercapacitor is very significant in the field of electrical energy storage which can be the solution for the current revolution in the electronic devices like mobile phones, camera flashes which needs flexible and miniaturized energy storage device with all non-aqueous components. The multiwalled carbon nanotubes (MWNTs have been synthesized by catalytic chemical vapor deposition technique over hydrogen decrepitated Mischmetal (Mm based AB3alloy hydride. The polymer dispersed MWNTs have been obtained by insitu polymerization and the metal oxide/MWNTs were synthesized by sol-gel method. Morphological characterizations of polymer dispersed MWNTs have been carried out using scanning electron microscopy (SEM, transmission electron microscopy (TEM and HRTEM. An assymetric double supercapacitor stack has been fabricated using polymer/MWNTs and metal oxide/MWNTs coated over flexible carbon fabric as electrodes and nafion®membrane as a solid electrolyte. Electrochemical performance of the supercapacitor stack has been investigated using cyclic voltammetry, galvanostatic charge-discharge, and electrochemical impedance spectroscopy.

  17. Electronic structure of the rotation twin stacking fault in β-ZnS

    International Nuclear Information System (INIS)

    Northrup, J.E.; Cohen, M.L.


    The electronic structure of the rotation twin stacking fault in β-ZnS is calculated with the self-consistent pseudopotential method. The stacking fault creates a potential barrier of approx.0.07 eV and induces the localization of stacking-fault resonances near the top of the valence band. Stacking-fault states are also predicted to exist in the various gaps in the projected valence-band structure

  18. Instant BlueStacks

    CERN Document Server

    Judge, Gary


    Get to grips with a new technology, understand what it is and what it can do for you, and then get to work with the most important features and tasks. A fast-paced, example-based approach guide for learning BlueStacks.This book is for anyone with a Mac or PC who wants to run Android apps on their computer. Whether you want to play games that are freely available for Android but not your computer, or you want to try apps before you install them on a physical device or use it as a development tool, this book will show you how. No previous experience is needed as this is written in plain English


    Thornton, J.D.


    This patent relates to liquid-liquid extraction columns having a means for pulsing the liquid in the column to give it an oscillatory up and down movement, and consists of a packed column, an inlet pipe for the dispersed liquid phase and an outlet pipe for the continuous liquid phase located in the direct communication with the liquid in the lower part of said column, an inlet pipe for the continuous liquid phase and an outlet pipe for the dispersed liquid phase located in direct communication with the liquid in the upper part of said column, a tube having one end communicating with liquid in the lower part of said column and having its upper end located above the level of said outlet pipe for the dispersed phase, and a piston and cylinder connected to the upper end of said tube for applying a pulsating pneumatic pressure to the surface of the liquid in said tube so that said surface rises and falls in said tube.

  20. Assessing Elementary Algebra with STACK (United States)

    Sangwin, Christopher J.


    This paper concerns computer aided assessment (CAA) of mathematics in which a computer algebra system (CAS) is used to help assess students' responses to elementary algebra questions. Using a methodology of documentary analysis, we examine what is taught in elementary algebra. The STACK CAA system,, which uses the CAS…

  1. HPC Software Stack Testing Framework

    Energy Technology Data Exchange (ETDEWEB)


    The HPC Software stack testing framework (hpcswtest) is used in the INL Scientific Computing Department to test the basic sanity and integrity of the HPC Software stack (Compilers, MPI, Numerical libraries and Applications) and to quickly discover hard failures, and as a by-product it will indirectly check the HPC infrastructure (network, PBS and licensing servers).

  2. Modeling Stone Columns. (United States)

    Castro, Jorge


    This paper reviews the main modeling techniques for stone columns, both ordinary stone columns and geosynthetic-encased stone columns. The paper tries to encompass the more recent advances and recommendations in the topic. Regarding the geometrical model, the main options are the "unit cell", longitudinal gravel trenches in plane strain conditions, cylindrical rings of gravel in axial symmetry conditions, equivalent homogeneous soil with improved properties and three-dimensional models, either a full three-dimensional model or just a three-dimensional row or slice of columns. Some guidelines for obtaining these simplified geometrical models are provided and the particular case of groups of columns under footings is also analyzed. For the latter case, there is a column critical length that is around twice the footing width for non-encased columns in a homogeneous soft soil. In the literature, the column critical length is sometimes given as a function of the column length, which leads to some disparities in its value. Here it is shown that the column critical length mainly depends on the footing dimensions. Some other features related with column modeling are also briefly presented, such as the influence of column installation. Finally, some guidance and recommendations are provided on parameter selection for the study of stone columns.

  3. Environmental assessment of phosphogypsum stacks

    International Nuclear Information System (INIS)

    Odat, M.; Al-Attar, L.; Raja, G.; Abdul Ghany, B.


    Phosphogypsum is one of the most important by-products of phosphate fertilizer industry. It is kept in large stacks to the west of Homs city. Storing Phosphogypsum as open stacks exposed to various environmental effects, wind and rain, may cause pollution of the surrounding ecosystem (soil, plant, water and air). This study was carried out in order to assess the environmental impact of Phosphogypsum stacks on the surrounding ecosystem. The obtained results show that Phosphogypsum stacks did not increase the concentration of radionuclides, i.e. Radon-222 and Radium-226, the external exposed dose of gamma rays, as well as the concentration of heavy metals in the components of the ecosystem, soil, plant, water and air, as their concentrations did not exceed the permissible limits. However, the concentration of fluorine in the upper layer of soil, located to the east of the Phosphogypsum stacks, increased sufficiently, especially in the dry period of the year. Also, the concentration of fluoride in plants growing up near-by the Phosphogypsum stacks was too high, exceeded the permissible levels. This was reflected in poising plants and animals, feeding on the plants. Consequently, increasing the concentration of fluoride in soil and plants is the main impact of Phosphogypsum stacks on the surrounding ecosystem. Minimising this effect could be achieved by establishing a 50 meter wide protection zone surrounding the Phosphogypsum stacks, which has to be planted with non palatable trees, such as pine and cypress, forming wind barriers. Increasing the concentrations of heavy metals and fluoride in infiltrated water around the stacks was high; hence cautions must be taken to prevent its usage in any application or disposal in adjacent rivers and leaks.(author)

  4. The general packed column : an analytical solution

    NARCIS (Netherlands)

    Gielen, J.L.W.


    The transient behaviour of a packed column is considered. The column, uniformly packed on a macroscopic scale, is multi-structured on the microscopic level: the solid phase consists of particles, which may differ in incidence, shape or size, and other relevant physical properties. Transport in the

  5. Design and performance of a passive dosimeter consisting of a stack of photostimulable phosphor (PSP) imaging plates (IP) based on BaF(Br, I):Eu{sup 2+}; Conception et performances d'un dosimetre passif compose d'un empilement d'ecrans radio-photoluminescents a memoire (ERLM) a BASE DE BaF(Br, I): Eu{sup 2+}

    Energy Technology Data Exchange (ETDEWEB)

    Jean-Paul Negre [CEA/DAM Ile de France, Departement de Physique Theorique et Appliquee, Service Physique des Plasmas et electromagnetisme, DIF/DPTA/SPPE, 91297 ARPAJON Cedex (France)


    This manuscript presents an original concept of passive, lightweight, and compact dosimeter based on a stack of BaFBr:Eu{sup 2+} photostimulable phosphor plates (Image Plate) alternating with high-Z metal screens. It describes the manufacture and the method to calibrate the dosimeter. This method consists in using a Co{sup 60} standard source and Monte Carlo N-Particle codes (MCNPX/MCNP5) to apply them to a large area of radiation energies, such as quasi mono-energetic radiation (Gamma rays decay of radioactive isotope, X-ray fluorescence), or continuous radiation spectra (Bremsstrahlung radiation, synchrotron light source). The measurement recurrence in the stack of couples 'metallic foil / IP' ensures consistency measurements, determines the threshold depth of electronic equilibrium (depending on the radiation energy) and allows us to infer the absolute dose in air (Kerma). The depth-dose curve in the stack and transmission measurements provide an estimate of the effective energy of incident radiations, report the presence of parasite scattered radiations and allow us to discriminate the nature of ionizing particles. The 2D features of the device are used to characterize the ballistic fate of charged particles in material thickness, which is of great interest with narrow particles beams. This dosimeter has remarkable advantages over other passive dosimeters, including a dynamic range larger than 10{sup 7} of linear photon dose detection from less than 0.5 {mu}Gy and up to several Gy for radiation energies between a few tens of keV and more than 10 MeV (20 MeV with Bremsstrahlung X-ray spectra). This concept originality consists in almost immediately getting the measurement results after an exposure and a single pass reading of the dosimeter. It can respond positively to most of the usual needs in radiation metrology: personal or environmental dosimetry (radiation protection); Controls / characterization / mapping around materials and emitting ionizing

  6. Radiotracer Imaging of Sediment Columns (United States)

    Moses, W. W.; O'Neil, J. P.; Boutchko, R.; Nico, P. S.; Druhan, J. L.; Vandehey, N. T.


    Nuclear medical PET and SPECT cameras routinely image radioactivity concentration of gamma ray emitting isotopes (PET - 511 keV; SPECT - 75-300 keV). We have used nuclear medical imaging technology to study contaminant transport in sediment columns. Specifically, we use Tc-99m (T1/2 = 6 h, Eγ = 140 keV) and a SPECT camera to image the bacteria mediated reduction of pertechnetate, [Tc(VII)O4]- + Fe(II) → Tc(IV)O2 + Fe(III). A 45 mL bolus of Tc-99m (32 mCi) labeled sodium pertechnetate was infused into a column (35cm x 10cm Ø) containing uranium-contaminated subsurface sediment from the Rifle, CO site. A flow rate of 1.25 ml/min of artificial groundwater was maintained in the column. Using a GE Millennium VG camera, we imaged the column for 12 hours, acquiring 44 frames. As the microbes in the sediment were inactive, we expected most of the iron to be Fe(III). The images were consistent with this hypothesis, and the Tc-99m pertechnetate acted like a conservative tracer. Virtually no binding of the Tc-99m was observed, and while the bolus of activity propagated fairly uniformly through the column, some inhomogeneity attributed to sediment packing was observed. We expect that after augmentation by acetate, the bacteria will metabolically reduce Fe(III) to Fe(II), leading to significant Tc-99m binding. Imaging sediment columns using nuclear medicine techniques has many attractive features. Trace quantities of the radiolabeled compounds are used (micro- to nano- molar) and the half-lives of many of these tracers are short (Image of Tc-99m distribution in a column containing Rifle sediment at four times.

  7. PieceStack: Toward Better Understanding of Stacked Graphs. (United States)

    Wu, Tongshuang; Wu, Yingcai; Shi, Conglei; Qu, Huamin; Cui, Weiwei


    Stacked graphs have been widely adopted in various fields, because they are capable of hierarchically visualizing a set of temporal sequences as well as their aggregation. However, because of visual illusion issues, connections between overly-detailed individual layers and overly-generalized aggregation are intercepted. Consequently, information in this area has yet to be fully excavated. Thus, we present PieceStack in this paper, to reveal the relevance of stacked graphs in understanding intrinsic details of their displayed shapes. This new visual analytic design interprets the ways through which aggregations are generated with individual layers by interactively splitting and re-constructing the stacked graphs. A clustering algorithm is designed to partition stacked graphs into sub-aggregated pieces based on trend similarities of layers. We then visualize the pieces with augmented encoding to help analysts decompose and explore the graphs with respect to their interests. Case studies and a user study are conducted to demonstrate the usefulness of our technique in understanding the formation of stacked graphs.

  8. ( Anogeissus leiocarpus ) timber columns

    African Journals Online (AJOL)

    A procedure for designing axially loaded Ayin (Anogeissus leiocarpus) wood column or strut has been investigated. Instead of the usual categorization of columns into short, intermediate and slender according to the value of slenderness ratio, a continuous column formula representing the three categories was derived.

  9. LAB3 Cosmic Ray Test Stand Analysis of Steel Stack Supports

    International Nuclear Information System (INIS)

    Cease, H.


    A cosmic ray test stand is being constructed at Lab 3. The stand consists of two stacks of steel plates one resting on top of the other. The top stack is composed of 6 plates of steel making an overall stack size of 34.5-inch x 40-inch x 99-inch. The bottom stack also has 6 layers of plate making an overall size of approximately 49.5-inch x 82-inch x 99-inch. The bottom stack is supported with three support legs. See drawing 3823.000ME-900428 for the individual plate orientation. The minimum support leg size and necessary welds between plates are determined.

  10. Supramolecular helical stacking of metallomesogens derived from enantiopure and racemic polycatenar oxazolines. (United States)

    Barberá, Joaquín; Cavero, Emma; Lehmann, Matthias; Serrano, José-Luis; Sierra, Teresa; Vázquez, Jesús T


    The present report undertakes a challenge of general interest in supramolecular chemistry: the achievement of helical organizations with controlled structure. To achieve this target we considered the possibility of inducing supramolecular chirality using molecules that were designed to organize into columnar mesophases. The use of oxazoline-derived ligands and metal coordination served as tools to prepare molecules with a phasmidic-like structure, which show columnar organization in the liquid crystalline state. To ensure the formation of chiral mesophases, these complexes bear stereogenic centers in the rigid coordination environment of the metal. X-ray and circular dichroism experiments have revealed that chirality transfer does indeed take place from the chiral molecule to the columnar liquid crystal organization. This chiral columnar organization appears as a helix consisting of stacks of molecules that rotate with respect to one another along the column while maintaining their mean planes parallel to each other. In fact, it has been concluded that packing of these polycatenar molecules must be more efficient upon rotation of a molecule with respect to the adjacent one along the column. Furthermore, the same type of helical supraorganization has been found to be present in the mesophase of the racemic mixture and the mixture of diastereomers prepared from the racemic ligand. In this case, segregation of the optical isomers is proposed to occur to give rise to both types of helix (right-handed and left-handed).

  11. Small Column Ion Exchange

    International Nuclear Information System (INIS)

    Huff, Thomas


    Small Column Ion Exchange (SCIX) leverages a suite of technologies developed by DOE across the complex to achieve lifecycle savings. Technologies are applicable to multiple sites. Early testing supported multiple sites. Balance of SRS SCIX testing supports SRS deployment. A forma Systems Engineering Evaluation (SEE) was performed and selected Small Column Ion Exchange columns containing Crystalline Silicotitanate (CST) in a 2-column lead/lag configuration. SEE considered use of Spherical Resorcinol-Formaldehyde (sRF). Advantages of approach at SRS include: (1) no new buildings, (2) low volume of Cs waste in solid form compared to aqueous strip effluent; and availability of downstream processing facilities for immediate processing of spent resin.

  12. User Driven Image Stacking for ODI Data and Beyond via a Highly Customizable Web Interface (United States)

    Hayashi, S.; Gopu, A.; Young, M. D.; Kotulla, R.


    While some astronomical archives have begun serving standard calibrated data products, the process of producing stacked images remains a challenge left to the end-user. The benefits of astronomical image stacking are well established, and dither patterns are recommended for almost all observing targets. Some archives automatically produce stacks of limited scientific usefulness without any fine-grained user or operator configurability. In this paper, we present PPA Stack, a web based stacking framework within the ODI - Portal, Pipeline, and Archive system. PPA Stack offers a web user interface with built-in heuristics (based on pointing, filter, and other metadata information) to pre-sort images into a set of likely stacks while still allowing the user or operator complete control over the images and parameters for each of the stacks they wish to produce. The user interface, designed using AngularJS, provides multiple views of the input dataset and parameters, all of which are synchronized in real time. A backend consisting of a Python application optimized for ODI data, wrapped around the SWarp software, handles the execution of stacking workflow jobs on Indiana University's Big Red II supercomputer, and the subsequent ingestion of the combined images back into the PPA archive. PPA Stack is designed to enable seamless integration of other stacking applications in the future, so users can select the most appropriate option for their science.

  13. Time-predictable Stack Caching

    DEFF Research Database (Denmark)

    Abbaspourseyedi, Sahar

    completely. Thus, in systems with hard deadlines the worst-case execution time (WCET) of the real-time software running on them needs to be bounded. Modern architectures use features such as pipelining and caches for improving the average performance. These features, however, make the WCET analysis more...... addresses, provides an opportunity to predict and tighten the WCET of accesses to data in caches. In this thesis, we introduce the time-predictable stack cache design and implementation within a time-predictable processor. We introduce several optimizations to our design for tightening the WCET while...... keeping the timepredictability of the design intact. Moreover, we provide a solution for reducing the cost of context switching in a system using the stack cache. In design of these caches, we use custom hardware and compiler support for delivering time-predictable stack data accesses. Furthermore...

  14. Glassy carbon based supercapacitor stacks

    Energy Technology Data Exchange (ETDEWEB)

    Baertsch, M.; Braun, A.; Koetz, R.; Haas, O. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)


    Considerable effort is being made to develop electrochemical double layer capacitors (EDLC) that store relatively large quantities of electrical energy and possess at the same time a high power density. Our previous work has shown that glassy carbon is suitable as a material for capacitor electrodes concerning low resistance and high capacity requirements. We present the development of bipolar electrochemical glassy carbon capacitor stacks of up to 3 V. Bipolar stacks are an efficient way to meet the high voltage and high power density requirements for traction applications. Impedance and cyclic voltammogram measurements are reported here and show the frequency response of a 1, 2, and 3 V stack. (author) 3 figs., 1 ref..

  15. Sequential injection chromatography with post-column reaction/derivatization for the determination of transition metal cations in natural water samples. (United States)

    Horstkotte, Burkhard; Jarošová, Patrícia; Chocholouš, Petr; Sklenářová, Hana; Solich, Petr


    In this work, the applicability of Sequential Injection Chromatography for the determination of transition metals in water is evaluated for the separation of copper(II), zinc(II), and iron(II) cations. Separations were performed using a Dionex IonPAC™ guard column (50mm×2mm i.d., 9 µm). Mobile phase composition and post-column reaction were optimized by modified SIMPLEX method with subsequent study of the concentration of each component. The mobile phase consisted of 2,6-pyridinedicarboxylic acid as analyte-selective compound, sodium sulfate, and formic acid/sodium formate buffer. Post-column addition of 4-(2-pyridylazo)resorcinol was carried out for spectrophotometric detection of the analytes׳ complexes at 530nm. Approaches to achieve higher robustness, baseline stability, and detection sensitivity by on-column stacking of the analytes and initial gradient implementation as well as air-cushion pressure damping for post-column reagent addition were studied. The method allowed the rapid separation of copper(II), zinc(II), and iron(II) within 6.5min including pump refilling and aspiration of sample and 1mmol HNO3 for analyte stacking on the separation column. High sensitivity was achieved applying an injection volume of up to 90µL. A signal repeatability of<2% RSD of peak height was found. Analyte recovery evaluated by spiking of different natural water samples was well suited for routine analysis with sub-micromolar limits of detection. Copyright © 2015 Elsevier B.V. All rights reserved.

  16. Measurements of proton energy spectra using a radiochromic film stack (United States)

    Filkins, T. M.; Steidle, Jessica; Ellison, D. M.; Steidle, Jeffrey; Freeman, C. G.; Padalino, S. J.; Fiksel, G.; Regan, S. P.; Sangster, T. C.


    The energy spectrum of protons accelerated from the rear-side of a thin foil illuminated with ultra-intense laser light from the OMEGA EP laser system at the University of Rochester's Laboratory for Laser Energetics (LLE) was measured using a stack of radiochromic film (RCF). The film stack consisted of four layers of Gafchromic HD-V2 film and four layers of Gafchromic MD-V2-55 film. Aluminum foils of various thicknesses were placed between each piece of RCF in the stack. This arrangement allowed protons with energies of 30 MeV to reach the back layer of RCF in the stack. The stack was placed in the detector plane of a Thomson parabola ion energy (TPIE) spectrometer. Each piece of film in the stack was scanned using a commercially available flat-bed scanner (Epson 10000XL). The resulting optical density was converted into proton fluence using an absolute calibration of the RCF obtained at the SUNY Geneseo 1.7 MV Pelletron accelerator laboratory. In these calibration measurements, the sensitivity of the radiochromic film was measured using monoenergetic protons produced by the accelerator. Details of the analysis procedure and the resulting proton energy spectra will be presented. Funded in part by a grant from the DOE through the Laboratory for Laser Energetics.

  17. Multiple Segmentation of Image Stacks

    DEFF Research Database (Denmark)

    Smets, Jonathan; Jaeger, Manfred


    We propose a method for the simultaneous construction of multiple image segmentations by combining a recently proposed “convolution of mixtures of Gaussians” model with a multi-layer hidden Markov random field structure. The resulting method constructs for a single image several, alternative...... segmentations that capture different structural elements of the image. We also apply the method to collections of images with identical pixel dimensions, which we call image stacks. Here it turns out that the method is able to both identify groups of similar images in the stack, and to provide segmentations...

  18. Simulating Small-Scale Object Stacking Using Stack Stability

    DEFF Research Database (Denmark)

    Kronborg Thomsen, Kasper; Kraus, Martin


    This paper presents an extension system to a closed-source, real-time physics engine for improving structured stacking behavior with small-scale objects such as wooden toy bricks. The proposed system was implemented and evaluated. The tests showed that the system is able to simulate several common...

  19. Center column design of the PLT

    International Nuclear Information System (INIS)

    Citrolo, J.; Frankenberg, J.


    The center column of the PLT machine is a secondary support member for the toroidal field coils. Its purpose is to decrease the bending moment at the nose of the coils. The center column design was to have been a stainless steel casting with the toroidal field coils grouped around the casting at installation, trapping it in place. However, the castings developed cracks during fabrication and were unsuitable for use. Installation of the coils proceeded without the center column. It then became necessary to redesign a center column which would be capable of installation with the toroidal field coils in place. The final design consists of three A-286 forgings. This paper discusses the final center column design and the influence that new knowledge, obtained during the power tests, had on the new design

  20. Pressurized electrolysis stack with thermal expansion capability (United States)

    Bourgeois, Richard Scott


    The present techniques provide systems and methods for mounting an electrolyzer stack in an outer shell so as to allow for differential thermal expansion of the electrolyzer stack and shell. Generally, an electrolyzer stack may be formed from a material with a high coefficient of thermal expansion, while the shell may be formed from a material having a lower coefficient of thermal expansion. The differences between the coefficients of thermal expansion may lead to damage to the electrolyzer stack as the shell may restrain the thermal expansion of the electrolyzer stack. To allow for the differences in thermal expansion, the electrolyzer stack may be mounted within the shell leaving a space between the electrolyzer stack and shell. The space between the electrolyzer stack and the shell may be filled with a non-conductive fluid to further equalize pressure inside and outside of the electrolyzer stack.

  1. The Direct FuelCell™ stack engineering (United States)

    Doyon, J.; Farooque, M.; Maru, H.

    FuelCell Energy (FCE) has developed power plants in the size range of 300 kW to 3 MW for distributed power generation. Field-testing of the sub-megawatt plants is underway. The FCE power plants are based on its Direct FuelCell™ (DFC) technology. This is so named because of its ability to generate electricity directly from a hydrocarbon fuel, such as natural gas, by reforming it inside the fuel cell stack itself. All FCE products use identical 8000 cm 2 cell design, approximately 350-400 cells per stack, external gas manifolds, and similar stack compression systems. The difference lies in the packaging of the stacks inside the stack module. The sub-megawatt system stack module contains a single horizontal stack whereas the MW-class stack module houses four identical vertical stacks. The commonality of the design, internal reforming features, and atmospheric operation simplify the system design, reduce cost, improve efficiency, increase reliability and maintainability. The product building-block stack design has been advanced through three full-size stack operations at company's headquarters in Danbury, CT. The initial proof-of-concept of the full-size stack design was verified in 1999, followed by a 1.5 year of endurance verification in 2000-2001, and currently a value-engineered stack version is in operation. This paper discusses the design features, important engineering solutions implemented, and test results of FCE's full-size DFC stacks.

  2. JCE Feature Columns (United States)

    Holmes, Jon L.


    The Features area of JCE Online is now readily accessible through a single click from our home page. In the Features area each column is linked to its own home page. These column home pages also have links to them from the online Journal Table of Contents pages or from any article published as part of that feature column. Using these links you can easily find abstracts of additional articles that are related by topic. Of course, JCE Online+ subscribers are then just one click away from the entire article. Finding related articles is easy because each feature column "site" contains links to the online abstracts of all the articles that have appeared in the column. In addition, you can find the mission statement for the column and the email link to the column editor that I mentioned above. At the discretion of its editor, a feature column site may contain additional resources. As an example, the Chemical Information Instructor column edited by Arleen Somerville will have a periodically updated bibliography of resources for teaching and using chemical information. Due to the increase in the number of these resources available on the WWW, it only makes sense to publish this information online so that you can get to these resources with a simple click of the mouse. We expect that there will soon be additional information and resources at several other feature column sites. Following in the footsteps of the Chemical Information Instructor, up-to-date bibliographies and links to related online resources can be made available. We hope to extend the online component of our feature columns with moderated online discussion forums. If you have a suggestion for an online resource you would like to see included, let the feature editor or JCE Online ( know about it. JCE Internet Features JCE Internet also has several feature columns: Chemical Education Resource Shelf, Conceptual Questions and Challenge Problems, Equipment Buyers Guide, Hal's Picks, Mathcad

  3. Stack semantics of type theory

    DEFF Research Database (Denmark)

    Coquand, Thierry; Mannaa, Bassel; Ruch, Fabian


    We give a model of dependent type theory with one univalent universe and propositional truncation interpreting a type as a stack, generalizing the groupoid model of type theory. As an application, we show that countable choice cannot be proved in dependent type theory with one univalent universe...

  4. Multilayer Piezoelectric Stack Actuator Characterization (United States)

    Sherrit, Stewart; Jones, Christopher M.; Aldrich, Jack B.; Blodget, Chad; Bao, Xioaqi; Badescu, Mircea; Bar-Cohen, Yoseph


    Future NASA missions are increasingly seeking to use actuators for precision positioning to accuracies of the order of fractions of a nanometer. For this purpose, multilayer piezoelectric stacks are being considered as actuators for driving these precision mechanisms. In this study, sets of commercial PZT stacks were tested in various AC and DC conditions at both nominal and extreme temperatures and voltages. AC signal testing included impedance, capacitance and dielectric loss factor of each actuator as a function of the small-signal driving sinusoidal frequency, and the ambient temperature. DC signal testing includes leakage current and displacement as a function of the applied DC voltage. The applied DC voltage was increased to over eight times the manufacturers' specifications to investigate the correlation between leakage current and breakdown voltage. Resonance characterization as a function of temperature was done over a temperature range of -180C to +200C which generally exceeded the manufacturers' specifications. In order to study the lifetime performance of these stacks, five actuators from one manufacturer were driven by a 60volt, 2 kHz sine-wave for ten billion cycles. The tests were performed using a Lab-View controlled automated data acquisition system that monitored the waveform of the stack electrical current and voltage. The measurements included the displacement, impedance, capacitance and leakage current and the analysis of the experimental results will be presented.

  5. Open stack thermal battery tests

    Energy Technology Data Exchange (ETDEWEB)

    Long, Kevin N. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Roberts, Christine C. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Grillet, Anne M. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Headley, Alexander J. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Fenton, Kyle [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Wong, Dennis [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Ingersoll, David [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)


    We present selected results from a series of Open Stack thermal battery tests performed in FY14 and FY15 and discuss our findings. These tests were meant to provide validation data for the comprehensive thermal battery simulation tools currently under development in Sierra/Aria under known conditions compared with as-manufactured batteries. We are able to satisfy this original objective in the present study for some test conditions. Measurements from each test include: nominal stack pressure (axial stress) vs. time in the cold state and during battery ignition, battery voltage vs. time against a prescribed current draw with periodic pulses, and images transverse to the battery axis from which cell displacements are computed. Six battery configurations were evaluated: 3, 5, and 10 cell stacks sandwiched between 4 layers of the materials used for axial thermal insulation, either Fiberfrax Board or MinK. In addition to the results from 3, 5, and 10 cell stacks with either in-line Fiberfrax Board or MinK insulation, a series of cell-free “control” tests were performed that show the inherent settling and stress relaxation based on the interaction between the insulation and heat pellets alone.

  6. Adding large EM stack support

    KAUST Repository

    Holst, Glendon


    Serial section electron microscopy (SSEM) image stacks generated using high throughput microscopy techniques are an integral tool for investigating brain connectivity and cell morphology. FIB or 3View scanning electron microscopes easily generate gigabytes of data. In order to produce analyzable 3D dataset from the imaged volumes, efficient and reliable image segmentation is crucial. Classical manual approaches to segmentation are time consuming and labour intensive. Semiautomatic seeded watershed segmentation algorithms, such as those implemented by ilastik image processing software, are a very powerful alternative, substantially speeding up segmentation times. We have used ilastik effectively for small EM stacks – on a laptop, no less; however, ilastik was unable to carve the large EM stacks we needed to segment because its memory requirements grew too large – even for the biggest workstations we had available. For this reason, we refactored the carving module of ilastik to scale it up to large EM stacks on large workstations, and tested its efficiency. We modified the carving module, building on existing blockwise processing functionality to process data in manageable chunks that can fit within RAM (main memory). We review this refactoring work, highlighting the software architecture, design choices, modifications, and issues encountered.

  7. Distillation Column Flooding Predictor

    Energy Technology Data Exchange (ETDEWEB)

    George E. Dzyacky


    The Flooding Predictor™ is a patented advanced control technology proven in research at the Separations Research Program, University of Texas at Austin, to increase distillation column throughput by over 6%, while also increasing energy efficiency by 10%. The research was conducted under a U. S. Department of Energy Cooperative Agreement awarded to George Dzyacky of 2ndpoint, LLC. The Flooding Predictor™ works by detecting the incipient flood point and controlling the column closer to its actual hydraulic limit than historical practices have allowed. Further, the technology uses existing column instrumentation, meaning no additional refining infrastructure is required. Refiners often push distillation columns to maximize throughput, improve separation, or simply to achieve day-to-day optimization. Attempting to achieve such operating objectives is a tricky undertaking that can result in flooding. Operators and advanced control strategies alike rely on the conventional use of delta-pressure instrumentation to approximate the column’s approach to flood. But column delta-pressure is more an inference of the column’s approach to flood than it is an actual measurement of it. As a consequence, delta pressure limits are established conservatively in order to operate in a regime where the column is never expected to flood. As a result, there is much “left on the table” when operating in such a regime, i.e. the capacity difference between controlling the column to an upper delta-pressure limit and controlling it to the actual hydraulic limit. The Flooding Predictor™, an innovative pattern recognition technology, controls columns at their actual hydraulic limit, which research shows leads to a throughput increase of over 6%. Controlling closer to the hydraulic limit also permits operation in a sweet spot of increased energy-efficiency. In this region of increased column loading, the Flooding Predictor is able to exploit the benefits of higher liquid

  8. Nuclear reactor control column

    International Nuclear Information System (INIS)

    Bachovchin, D.M.


    The nuclear reactor control column comprises a column disposed within the nuclear reactor core having a variable cross-section hollow channel and containing balls whose vertical location is determined by the flow of the reactor coolant through the column. The control column is divided into three basic sections wherein each of the sections has a different cross-sectional area. The uppermost section of the control column has the greatest crosssectional area, the intermediate section of the control column has the smallest cross-sectional area, and the lowermost section of the control column has the intermediate cross-sectional area. In this manner, the area of the uppermost section can be established such that when the reactor coolant is flowing under normal conditions therethrough, the absorber balls will be lifted and suspended in a fluidized bed manner in the upper section. However, when the reactor coolant flow falls below a predetermined value, the absorber balls will fall through the intermediate section and into the lowermost section, thereby reducing the reactivity of the reactor core and shutting down the reactor

  9. Exact and heuristic solutions to the Double TSP with Multiple Stacks

    DEFF Research Database (Denmark)

    Petersen, Hanne Løhmann; Archetti, Claudia; Madsen, Oli B.G.

    The double travelling salesman problem with multiple stacks (DTSPMS) is a pickup and delivery problem where pickups and deliveries are separated, such that all pickup operations are performed before the first delivery takes place. All operations are carried out by one vehicle and no reloading...... is allowed. The vehicle provides several separated (horizontal) stacks/rows for the transportation of the orders, such that each stack is accessed using a LIFO principle, independently of the other stacks. In a real-life setting the dimensions of the problem is 33 orders each consisting of one euro...

  10. Development and durability of SOFC stacks

    Energy Technology Data Exchange (ETDEWEB)

    Beeaff, D.; Dinesen, A.R.; Mikkelsen, Lars; Nielsen, Karsten A.; Solvang, M.; Hendriksen, Peter V.


    The present project is a part of the Danish SOFC programme, which has the overall aim of establishing a Danish production of SOFC - cells, stacks and systems for economical and environmentally friendly power production. The aim of the present project was to develop and demonstrate (on a small scale, few cells, few thousand hours) a durable, thermally cyclable stack with high performance at 750 deg. C. Good progress towards this target has been made and demonstrated at the level of stack-elements (one cell between two interconnects) or small stacks (3 5 cells). Three different stacks or stack-elements have been operated for periods exceeding 3000 hr. The work has covered development of stack-components (seals, interconnects, coatings, contact layers), establishment of procedures for stack assembly and initiation, and detailed electrical characterisation with the aims of identifying performance limiting factors as well as long term durability. Further, post test investigations have been carried out to identify possible degradation mechanisms. (BA)

  11. Image transfer by cascaded stack of photonic crystal and air layers

    NARCIS (Netherlands)

    Shen, C.; Michielsen, K.; Raedt, H. De


    We demonstrate image transfer by a cascaded stack consisting of two and three triangular-lattice photonic crystal slabs separated by air. The quality of the image transfered by the stack is sensitive to the air/photonic crystal interface termination and the frequency. Depending on the frequency and

  12. Buckling of liquid columns

    NARCIS (Netherlands)

    Habibi, M.; Rahmani, Y.; Bonn, D.; Ribe, N.M.


    Under appropriate conditions, a column of viscous liquid falling onto a rigid surface undergoes a buckling instability. Here we show experimentally and theoretically that liquid buckling exhibits a hitherto unsuspected complexity involving three different modes—viscous, gravitational, and

  13. Solvent extraction columns

    International Nuclear Information System (INIS)

    Middleton, P.; Smith, J.R.


    In pulsed columns for use in solvent extraction processes, e.g. the reprocessing of nuclear fuel, the horizontal perforated plates inside the column are separated by interplate spacers manufactured from metallic neutron absorbing material. The spacer may be in the form of a spiral or concentric circles separated by radial limbs, or may be of egg-box construction. Suitable neutron absorbing materials include stainless steel containing boron or gadolinium, hafnium metal or alloys of hafnium. (UK)

  14. Exact Solutions to the Double TSP with Multiple Stacks

    DEFF Research Database (Denmark)

    Petersen, Hanne Løhmann; Archetti, Claudia; Madsen, Oli B.G.

    In the Double Travelling Salesman Problem with Multiple Stacks (DTSPMS) a set of orders is given, each one requiring transportation of one item from a customer in a pickup region to a customer in a delivery region. The vehicle available for the transportation in each region carries a container......, which is organised in rows of given length. Each row is handled independently from the others according to a LIFO stack policy. The DTSPMS consists in determining the pickup tour, the loading plan of the container and the delivery tour in such a way that the total length of the two tours is minimised...

  15. Steel beam to reinforced concrete column joints using steel plate connections. Pt. 2. Structural behavior of joints under cyclic loading; Koban setsugobu wo mochiita tekkin concrete chu to tekkotsu hari tono setsugobu ni kansuru kenkyu. 2. Churyo jujigata honegumi no suihei karyoku jikken

    Energy Technology Data Exchange (ETDEWEB)

    Suzuki, K.; Tomitas, A.; Honma, K.; Ueno, M. [Kajima Corp., Tokyo (Japan)


    A column/beam structure having reinforced concrete columns and steel beams (RC column/S beam structure) enables the assemblies to be manufactured in a plant by using PCa for the column including joints, and allows the assembling work at a job site to be performed by a dry/stacking construction method consisting mostly of the assembly operation. The writers developed a steel plate joint, a steel plate with an opening in the center, which is fixed inside a column by merely penetrating the joint with main reinforcements of the column, as a new joining method in the RC column/S beam construction that facilitates the PCa column. As a result of a previously implemented experiment of drawing out the joint, it was confirmed that the joint fixed by penetrating with the main reinforcements showed a sufficient fixing performance without special reinforcement, and that no damage was caused locally to the main reinforcements by drawing out the steel plate for example. In the subject research, for the purpose of grasping the basic dynamical properties of a bridge using the joint, a framework test was conducted on the six specimens with a reinforcing method varied for the joint. As a result of the test, the joint, having the opening in the center and penetration with the column main reinforcements, demonstrated a full fixing performance, ensuring a stable load/deformation relation up to a layer deforming angle of R={+-}25rad. In particular, no surface separation was recognized between the joint and the column concrete, and no local fall-off or the like of the joint was confirmed. (translated by NEDO)

  16. Communication: Thermodynamics of stacking disorder in ice nuclei (United States)

    Quigley, D.


    A simple Ising-like model for the stacking thermodynamics of ice 1 is constructed for nuclei in supercooled water, and combined with classical nucleation theory. For relative stabilities of cubic and hexagonal ice I within the range of experimental estimates, this predicts critical nuclei are stacking disordered at strong sub-cooling, consistent with recent experiments. At higher temperatures nucleation of pure hexagonal ice is recovered. Lattice-switching Monte-Carlo is applied to accurately compute the relative stability of cubic and hexagonal ice for the popular mW model of water. Results demonstrate that this model fails to adequately capture the relative energetics of the two polytypes, leading to stacking disorder at all temperatures.

  17. Electric toy vehicle powered by a PEMFC stack

    Energy Technology Data Exchange (ETDEWEB)

    Beneito, Ruben; Vilaplana, Joaquin; Gisbert, Santiago [Technological Institute for Toy (AIJU), 03440 Ibi (Spain)


    The article describes the design and development of an electric toy vehicle powered by a fuel cell stack. The system consisted of a 150 W PEMFC stack powered by hydrogen/air, a tank of metal hydrides of AB (TiFe) alloy type with a capacity of 300 standard litres, for storing hydrogen, and an electronic power device based on electrolytic capacitors, to supply peak power demands during acceleration and start up of the vehicle. The air supply was provided by a fan preceded by a filter, and in a similar manner the stack was cooled by an air ventilation system. An electrovalve was used to supply H{sub 2} in dead-ended mode. All the components were integrated in the vehicle, and the prototype was tested in real working conditions, in a test bench and by children. (author)

  18. Multipole Stack for the 800 MeV PS Booster

    CERN Multimedia


    The 800 MeV PS Booster had seen first beam in its 4 superposed rings in 1972, routine operation began in 1973. In the strive for ever higher beam intensities, the need for additional multipole lenses became evident. After detailed studies, the manufacture of 8 stacks of multipoles was launched in 1974. Each stack consists of 4 superposed multipoles and each multipole has 4 concentric shells. From the innermost to the outermost shell, Type A contains octupole, skew-octupole, sextupole, skew-sextupole. Type B contains skew-octupole, skew-sextupole, vertical dipole, horizontal dipole. Completion of installation in 1976 opened the way to higher beam intensities. M. Battiaz is seen here with a multipole stack and its many electrical connections.

  19. Lightweight Stacks of Direct Methanol Fuel Cells (United States)

    Narayanan, Sekharipuram; Valdez, Thomas


    An improved design concept for direct methanol fuel cells makes it possible to construct fuel-cell stacks that can weigh as little as one-third as much as do conventional bipolar fuel-cell stacks of equal power. The structural-support components of the improved cells and stacks can be made of relatively inexpensive plastics. Moreover, in comparison with conventional bipolar fuel-cell stacks, the improved fuel-cell stacks can be assembled, disassembled, and diagnosed for malfunctions more easily. These improvements are expected to bring portable direct methanol fuel cells and stacks closer to commercialization. In a conventional bipolar fuel-cell stack, the cells are interspersed with bipolar plates (also called biplates), which are structural components that serve to interconnect the cells and distribute the reactants (methanol and air). The cells and biplates are sandwiched between metal end plates. Usually, the stack is held together under pressure by tie rods that clamp the end plates. The bipolar stack configuration offers the advantage of very low internal electrical resistance. However, when the power output of a stack is only a few watts, the very low internal resistance of a bipolar stack is not absolutely necessary for keeping the internal power loss acceptably low.

  20. Solid Oxide Fuel Cell Stack Diagnostics

    DEFF Research Database (Denmark)

    Mosbæk, Rasmus Rode; Barfod, Rasmus Gottrup

    . An operating stack is subject to compositional gradients in the gaseous reactant streams, and temperature gradients across each cell and across the stack, which complicates detailed analysis. Several experimental stacks from Topsoe Fuel Cell A/S were characterized using Electrochemical Impedance Spectroscopy...... (EIS). The stack measurement geometry was optimized for EIS by careful selection of the placement of current feeds and voltage probes in order to minimize measurement errors. It was demonstrated that with the improved placement of current feeds and voltage probes it is possible to separate the loss...... in the hydrogen fuel gas supplied to the stack. EIS was used to examine the long-term behavior and monitor the evolution of the impedance of each of the repeating units and the whole stack. The observed impedance was analyzed in detail for one of the repeating units and the whole stack and the losses reported...

  1. Five points on columns

    Directory of Open Access Journals (Sweden)

    Kathleen S Rockland


    Full Text Available Abstract “Column,” like “gene,” has both conceptual and linguistic shortcomings. The simple question “what is a column” is not easy to answer and the word itself is not easy to replace. In the present article, I have selected five points, in no way comprehensive or canonical, but which may nevertheless serve as a prompt and aid for further discussions and reevaluation. These are: that anatomical columns are not solid structures, that they are part of locally interdigitating systems, that any delimited column also participates in a widely distributed network, that columns are not an obligatory cortical feature, and that columns (as “modules” occur widely in the brain in non-cortical structures. I focus on the larger scale macrocolumns, mainly from an anatomical perspective. My position is that cortical organization is inherently dynamic and likely to incorporate multiple processing styles. One can speculate that the distributed mappings within areas like piriform cortex may resemble at least one mode of neocortical processing strategy.

  2. Decoding the Pantheon Columns

    Directory of Open Access Journals (Sweden)

    Gerd Grasshoff


    Full Text Available The goal of this study has been to reconstruct the design principles underlying the construction of the Pantheon’s portico columns as well as to demonstrate how digital investigation methods and models can be used to improve our understanding of ancient architectural knowledge. Thanks to the data of the Bern Digital Pantheon Model, a synthesis of all the scanned surface points obtained during a digitization campaign of the Karman Center for Advanced Studies in the Humanities of the University of Bern in 2005, we have been able to determine empirically the column profiles of the portico with unprecedented precision. A second stage of our investigation involved explaining the profile of the column shafts by a construction model that takes into account the parameters recommended by Vitruvius and design methods such as those that can be found in the construction drawings discovered at Didyma. Our analysis shows that the design principles of the portico’s columns can be successfully reconstructed, and has led to the surprising result that at least two different variants of a simple circle construction were used. Finally, we have been able to deduce from the distribution of the different profile types among the columns that the final profiles were designed and executed in Rome.

  3. Assembly for connecting the column ends of two capillary columns

    International Nuclear Information System (INIS)

    Kolb, B.; Auer, M.; Pospisil, P.


    In gas chromatography, the column ends of two capillary columns are inserted into a straight capillary from both sides forming annular gaps. The capillary is located in a tee out of which the capillary columns are sealingly guided, and to which carrier gas is supplied by means of a flushing flow conduit. A ''straight-forward operation'' having capillary columns connected in series and a ''flush-back operation'' are possible. The dead volume between the capillary columns can be kept small

  4. Behavior of reinforced concrete columns strenghtened by partial jacketing

    Directory of Open Access Journals (Sweden)


    Full Text Available This article presents the study of reinforced concrete columns strengthened using a partial jacket consisting of a 35mm self-compacting concrete layer added to its most compressed face and tested in combined compression and uniaxial bending until rupture. Wedge bolt connectors were used to increase bond at the interface between the two concrete layers of different ages. Seven 2000 mm long columns were tested. Two columns were cast monolithically and named PO (original column e PR (reference column. The other five columns were strengthened using a new 35 mm thick self-compacting concrete layer attached to the column face subjected to highest compressive stresses. Column PO had a 120mm by 250 mm rectangular cross section and other columns had a 155 mm by 250mm cross section after the strengthening procedure. Results show that the ultimate resistance of the strengthened columns was more than three times the ultimate resistance of the original column PO, indicating the effectiveness of the strengthening procedure. Detachment of the new concrete layer with concrete crushing and steel yielding occurred in the strengthened columns.

  5. Performance of air-cathode stacked microbial fuel cells systems for wastewater treatment and electricity production. (United States)

    Estrada-Arriaga, Edson Baltazar; Guillen-Alonso, Yvonne; Morales-Morales, Cornelio; García-Sánchez, Liliana; Bahena-Bahena, Erick Obed; Guadarrama-Pérez, Oscar; Loyola-Morales, Félix


    Two different air-cathode stacked microbial fuel cell (MFC) configurations were evaluated under continuous flow during the treatment of municipal wastewater and electricity production at a hydraulic retention time (HRT) of 3, 1, and 0.5 d. Stacked MFC 1 was formed by 20 individual air-cathode MFC units. The second stacked MFC (stacked MFC 2) consisted of 40 air-cathode MFC units placed in a shared reactor. The maximum voltages produced at closed circuit (1,000 Ω) were 170 mV for stacked MFC 1 and 94 mV for stacked MFC 2. Different power densities in each MFC unit were obtained due to a potential drop phenomenon and to a change in chemical oxygen demand (COD) concentrations inside reactors. The maximum power densities from individual MFC units were up to 1,107 mW/m 2 for stacked MFC 1 and up to 472 mW/m 2 for stacked MFC 2. The maximum power densities in stacked MFC 1 and MFC 2 connected in series were 79 mW/m 2 and 4 mW/m 2 , respectively. Electricity generation and COD removal efficiencies were reduced when the HRT was decreased. High removal efficiencies of 84% of COD, 47% of total nitrogen, and 30% of total phosphorus were obtained during municipal wastewater treatment.

  6. Slender CRC Columns


    Aarup, Bendt; Jensen, Lars Rom; Ellegaard, Peter


    CRC is a high-performance steel fibre reinforced concrete with a typical compressive strength of 150 MPa. Design methods for a number of structural elements have been developed since CRC was invented in 1986, but the current project set out to further investigate the range of columns for which current design guides can be used. The columns tested had a slenderness varying from 1.11 to 12.76 and a reinforcement ratio (area of rebar to area of concrete) ranging from 0 to 8.8 %. A total of 77 te...

  7. Vertically stacked nanocellulose tactile sensor. (United States)

    Jung, Minhyun; Kim, Kyungkwan; Kim, Bumjin; Lee, Kwang-Jae; Kang, Jae-Wook; Jeon, Sanghun


    Paper-based electronic devices are attracting considerable attention, because the paper platform has unique attributes such as flexibility and eco-friendliness. Here we report on what is claimed to be the firstly fully integrated vertically-stacked nanocellulose-based tactile sensor, which is capable of simultaneously sensing temperature and pressure. The pressure and temperature sensors are operated using different principles and are stacked vertically, thereby minimizing the interference effect. For the pressure sensor, which utilizes the piezoresistance principle under pressure, the conducting electrode was inkjet printed on the TEMPO-oxidized-nanocellulose patterned with micro-sized pyramids, and the counter electrode was placed on the nanocellulose film. The pressure sensor has a high sensitivity over a wide range (500 Pa-3 kPa) and a high durability of 10 4 loading/unloading cycles. The temperature sensor combines various materials such as poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS), silver nanoparticles (AgNPs) and carbon nanotubes (CNTs) to form a thermocouple on the upper nanocellulose layer. The thermoelectric-based temperature sensors generate a thermoelectric voltage output of 1.7 mV for a temperature difference of 125 K. Our 5 × 5 tactile sensor arrays show a fast response, negligible interference, and durable sensing performance.

  8. Practical column design guide

    CERN Document Server

    Nitsche, M


    This book highlights the aspects that need to be considered when designing distillation columns in practice. It discusses the influencing parameters as well as the equations governing them, and presents several numerical examples. The book is intended both for experienced designers and for those who are new to the subject.

  9. Columns in Clay (United States)

    Leenhouts, Robin


    This article describes a clay project for students studying Greece and Rome. It provides a wonderful way to learn slab construction techniques by making small clay column capitols. With this lesson, students learn architectural vocabulary and history, understand the importance of classical architectural forms and their influence on today's…

  10. Steel column base classification


    Jaspart, J.P.; Wald, F.; Weynand, K.; Gresnigt, A.M.


    The influence of the rotational characteristics of the column bases on the structural frame response is discussed and specific design criteria for stiffness classification into semi-rigid and rigid joints are derived. The particular case of an industrial portal frame is then considered. Peer reviewed

  11. European Analytical Column

    DEFF Research Database (Denmark)

    Karlberg, B.; Grasserbauer, M.; Andersen, Jens Enevold Thaulov


    The European Analytical Column has once more invited a guest columnist to give his views on various matters related to analytical chemistry in Europe. This year, we have invited Professor Manfred Grasserbauer of the Vienna University of Technology to present some of the current challenges for Eur...

  12. Generalized data stacking programming model with applications

    Directory of Open Access Journals (Sweden)

    Hala Samir Elhadidy


    Full Text Available Recent researches have shown that, everywhere in various sciences the systems are following stacked-based stored change behavior when subjected to events or varying environments “on and above” their normal situations. This paper presents a generalized data stack programming (GDSP model which is developed to describe the system changes under varying environment. These changes which are captured with different ways such as sensor reading are stored in matrices. Extraction algorithm and identification technique are proposed to extract the different layers between images and identify the stack class the object follows; respectively. The general multi-stacking network is presented including the interaction between various stack-based layering of some applications. The experiments prove that the concept of stack matrix gives average accuracy of 99.45%.

  13. Flexural characteristics of a stack leg

    International Nuclear Information System (INIS)

    Cook, J.


    A 30 MV tandem Van de Graaff accelerator is at present under construction at Daresbury Laboratory. The insulating stack of the machine is of modular construction, each module being 860 mm in length. Each live section stack module contains 8 insulating legs mounted between bulkhead rings. The design, fabrication (from glass discs bonded to stainless steel discs using an epoxy film adhesive) and testing of the stack legs is described. (U.K.)

  14. Hydrogen Embrittlement And Stacking-Fault Energies (United States)

    Parr, R. A.; Johnson, M. H.; Davis, J. H.; Oh, T. K.


    Embrittlement in Ni/Cu alloys appears related to stacking-fault porbabilities. Report describes attempt to show a correlation between stacking-fault energy of different Ni/Cu alloys and susceptibility to hydrogen embrittlement. Correlation could lead to more fundamental understanding and method of predicting susceptibility of given Ni/Cu alloy form stacking-fault energies calculated from X-ray diffraction measurements.

  15. A small mono-polar direct methanol fuel cell stack with passive operation (United States)

    Chan, Y. H.; Zhao, T. S.; Chen, R.; Xu, C.

    A passive direct methanol fuel cell (DMFC) stack that consists of six unit cells was designed, fabricated, and tested. The stack was tested with different methanol concentrations under ambient conditions. It was found that the stack performance increased when the methanol concentration inside the fuel tank was increased from 2.0 to 6.0 M. The improved performance is primarily due to the increased cell temperature as a result of the exothermic reaction between the permeated methanol and oxygen on the cathode. Moreover, the increased cell temperature enhanced the water evaporation rate on the air-breathing cathode, which significantly reduced water flooding on the cathode and further improved the stack performance. This passive DMFC stack, providing 350 mW at 1.8 V, was successfully applied to power a seagull display kit. The seagull display kit can continuously run for about 4 h on a single charge of 25 cm 3 4.0-M methanol solution.

  16. California dreaming?[PEM stacks

    Energy Technology Data Exchange (ETDEWEB)

    Crosse, J.


    Hyundai's Santa Fe FCEV will be on sale by the end of 2002. Hyundai uses PEM stacks that are manufactured by International Fuel Cells (IFC), a division of United Technologies. Santa Fe is equipped with a 65 kW electric powertrain of Enova systems and Shell's new gasoline reformer called Hydrogen Source. Eugene Jang, Senior Engineer - Fuel Cell and Materials at Hyundai stated that the compressor related losses on IFC system are below 3%. The maximum speed offered by the vehicle is estimated as 123km/hr while the petrol equivalent fuel consumption is quoted between 5.6L/100 km and 4.8L/100 km. Santa Fe is a compact vehicle offering better steering response and a pleasant drive. (author)

  17. Tunable infrared plasmonic devices using graphene/insulator stacks (United States)

    Yan, Hugen; Li, Xuesong; Chandra, Bhupesh; Tulevski, George; Wu, Yanqing; Freitag, Marcus; Zhu, Wenjuan; Avouris, Phaedon; Xia, Fengnian


    The collective oscillation of carriers--the plasmon--in graphene has many desirable properties, including tunability and low loss. However, in single-layer graphene, the dependence on carrier concentration of both the plasmonic resonance frequency and magnitude is relatively weak, limiting its applications in photonics. Here, we demonstrate transparent photonic devices based on graphene/insulator stacks, which are formed by depositing alternating wafer-scale graphene sheets and thin insulating layers, then patterning them together into photonic-crystal-like structures. We show experimentally that the plasmon in such stacks is unambiguously non-classical. Compared with doping in single-layer graphene, distributing carriers into multiple graphene layers effectively enhances the plasmonic resonance frequency and magnitude, which is different from the effect in a conventional semiconductor superlattice and is a direct consequence of the unique carrier density scaling law of the plasmonic resonance of Dirac fermions. Using patterned graphene/insulator stacks, we demonstrate widely tunable far-infrared notch filters with 8.2 dB rejection ratios and terahertz linear polarizers with 9.5 dB extinction ratios. An unpatterned stack consisting of five graphene layers shields 97.5% of electromagnetic radiation at frequencies below 1.2 THz. This work could lead to the development of transparent mid- and far-infrared photonic devices such as detectors, modulators and three-dimensional metamaterial systems.

  18. Nine Words - Nine Columns

    DEFF Research Database (Denmark)

    Trempe Jr., Robert B.; Buthke, Jan


    of computational and mechanical processes towards an anesthetic. Each team received a single word, translating and evolving that word first into a double-curved computational surface, next a ruled computational surface, and then a physically shaped foam mold via a 6-axis robot. The foam molds then operated...... as formwork for the shaping of wood veneer. The resulting columns ‘wear’ every aspect of this design pipeline process and display the power of process towards an architectural resolution....

  19. Slender CRC Columns

    DEFF Research Database (Denmark)

    Aarup, Bendt; Jensen, Lars Rom; Ellegaard, Peter


    in standard fire conditions. The tests showed good correlation between test results and results calculated according to established deisgn guides. The fire tests demonstrate that the load capacity of slender columns can be reduced very quickly due to thermal stresses and a reduction of stiffness - also...... in cases where temperature at the rebar is still relatively low. However, guidelines for achieving acceptable fire resistance can be determined based on the test results....

  20. Nine Words - Nine Columns

    DEFF Research Database (Denmark)

    Trempe Jr., Robert B.; Buthke, Jan


    This book records the efforts of a one-week joint workshop between Master students from Studio 2B of Arkitektskolen Aarhus and Master students from the Harbin Institute of Technology in Harbin, China. The workshop employed nine action words to instigate team-based investigation into the effects o...... as formwork for the shaping of wood veneer. The resulting columns ‘wear’ every aspect of this design pipeline process and display the power of process towards an architectural resolution....

  1. Monolithic column in gas chromatography. (United States)

    Kurganov, A


    Monolithic columns invented in chromatographic praxis almost 40 years ago gained nowadays a lot of popularity in separations by liquid chromatographic technique. At the same time, application of monolithic columns in gas chromatography is less common and only a single review published by Svec et al. covers this field of research. Since that time a lot of new findings on application and properties of monolithic columns in gas chromatography have been published in the literature deserving consideration and discussion. This review considers preparation of monolithic columns for GC, an impact of preparation conditions on column performance, optimization of separation conditions for GC analysis on monolithic columns and other important aspects of preparation and usage of monolithic capillary columns in GC. A final part of the review discusses the modern trends and possible applications in the future of capillary monolithic columns in GC. Copyright © 2013 Elsevier B.V. All rights reserved.

  2. Stacking technology for a space constrained microsystem

    DEFF Research Database (Denmark)

    Heschel, Matthias; Kuhmann, Jochen Friedrich; Bouwstra, Siebe


    In this paper we present a stacking technology for an integrated packaging of an intelligent transducer which is formed by a micromachined silicon transducer and an integrated circuit chip. Transducer and circuitry are stacked on top of each other with an intermediate chip in between. The bonding...

  3. Vector Fields and Flows on Differentiable Stacks

    DEFF Research Database (Denmark)

    A. Hepworth, Richard


    This paper introduces the notions of vector field and flow on a general differentiable stack. Our main theorem states that the flow of a vector field on a compact proper differentiable stack exists and is unique up to a uniquely determined 2-cell. This extends the usual result on the existence...... of vector fields....

  4. 40 CFR 61.44 - Stack sampling. (United States)


    ... 40 Protection of Environment 8 2010-07-01 2010-07-01 false Stack sampling. 61.44 Section 61.44 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL... Firing § 61.44 Stack sampling. (a) Sources subject to § 61.42(b) shall be continuously sampled, during...

  5. Learning OpenStack networking (Neutron)

    CERN Document Server

    Denton, James


    If you are an OpenStack-based cloud operator with experience in OpenStack Compute and nova-network but are new to Neutron networking, then this book is for you. Some networking experience is recommended, and a physical network infrastructure is required to provide connectivity to instances and other network resources configured in the book.

  6. Project W-420 stack monitoring system upgrades

    International Nuclear Information System (INIS)



    This project will execute the design, procurement, construction, startup, and turnover activities for upgrades to the stack monitoring system on selected Tank Waste Remediation System (TWRS) ventilation systems. In this plan, the technical, schedule, and cost baselines are identified, and the roles and responsibilities of project participants are defined for managing the Stack Monitoring System Upgrades, Project W-420

  7. On the "stacking fault" in copper

    NARCIS (Netherlands)

    Fransens, J.R.; Pleiter, F


    The results of a perturbed gamma-gamma angular correlations experiment on In-111 implanted into a properly cut single crystal of copper show that the defect known in the literature as "stacking fault" is not a planar faulted loop but a stacking fault tetrahedron with a size of 10-50 Angstrom.

  8. Status of MCFC stack technology at IHI

    Energy Technology Data Exchange (ETDEWEB)

    Hosaka, M.; Morita, T.; Matsuyama, T.; Otsubo, M. [Ishikawajima-Harima Heavy Industries Co., Ltd., Tokyo (Japan)


    The molten carbonate fuel cell (MCFC) is a promising option for highly efficient power generation possible to enlarge. IHI has been studying parallel flow MCFC stacks with internal manifolds that have a large electrode area of 1m{sup 2}. IHI will make two 250 kW stacks for MW plant, and has begun to make cell components for the plant. To improve the stability of stack, soft corrugated plate used in the separator has been developed, and a way of gathering current from stacks has been studied. The DC output potential of the plant being very high, the design of electric insulation will be very important. A 20 kW short stack test was conducted in 1995 FY to certificate some of the improvements and components of the MW plant. These activities are presented below.

  9. Study on the polarity, solubility, and stacking characteristics of asphaltenes

    KAUST Repository

    Zhang, Long-li


    The structure and transformation of fused aromatic ring system in asphaltenes play an important role in the character of asphaltenes, and in step affect the properties of heavy oils. Polarity, solubility and structural characteristics of asphaltenes derived from Tahe atmospheric residue (THAR) and Tuo-826 heavy crude oil (Tuo-826) were analyzed for study of their internal relationship. A fractionation method was used to separate the asphaltenes into four sub-fractions, based on their solubility in the mixed solvent, for the study of different structural and physical-chemical properties, such as polarity, solubility, morphology, stacking characteristics, and mean structural parameters. Transmission electron microscope (TEM) observation can present the intuitive morphology of asphaltene molecules, and shows that the structure of asphaltenes is in local order as well as long range disorder. The analysis results showed that n-heptane asphaltenes of THAR and Tuo-826 had larger dipole moment values, larger fused aromatic ring systems, larger mean number of stacking layers, and less interlayer spacing between stacking layers than the corresponding n-pentane asphaltenes. The sub-fractions that were inclined to precipitate from the mixture of n-heptane and tetrahydrofuran had larger polarity and less solubility. From the first sub-fraction to the fourth sub-fraction, polarity, mean stacking numbers, and average layer size from the TEM images follow a gradual decrease. The structural parameters derived from TEM images could reflect the largest fused aromatic ring system in asphaltene molecule, yet the parameters derived from 1H NMR data reflected the mean message of poly-aromatic ring systems. The structural parameters derived from TEM images were more consistent with the polarity variation of sub-fractions than those derived from 1H NMR data, which indicates that the largest fused aromatic ring system will play a more important role in the stacking characteristics of

  10. A cross-stacked plasmonic nanowire network for high-contrast femtosecond optical switching. (United States)

    Lin, Yuanhai; Zhang, Xinping; Fang, Xiaohui; Liang, Shuyan


    We report an ultrafast optical switching device constructed by stacking two layers of gold nanowires into a perpendicularly crossed network, which works at a speed faster than 280 fs with an on/off modulation depth of about 22.4%. The two stacks play different roles in enhancing consistently the optical switching performance due to their different dependence on the polarization of optical electric fields. The cross-plasmon resonance based on the interaction between the perpendicularly stacked gold nanowires and its Fano-coupling with Rayleigh anomaly is the dominant mechanism for such a high-contrast optical switching device.

  11. The impact of stack geometry and mean pressure on cold end temperature of stack in thermoacoustic refrigeration systems (United States)

    Wantha, Channarong


    This paper reports on the experimental and simulation studies of the influence of stack geometries and different mean pressures on the cold end temperature of the stack in the thermoacoustic refrigeration system. The stack geometry was tested, including spiral stack, circular pore stack and pin array stack. The results of this study show that the mean pressure of the gas in the system has a significant impact on the cold end temperature of the stack. The mean pressure of the gas in the system corresponds to thermal penetration depth, which results in a better cold end temperature of the stack. The results also show that the cold end temperature of the pin array stack decreases more than that of the spiral stack and circular pore stack geometry by approximately 63% and 70%, respectively. In addition, the thermal area and viscous area of the stack are analyzed to explain the results of such temperatures of thermoacoustic stacks.

  12. Column: Every Last Byte

    Directory of Open Access Journals (Sweden)

    Simson Garfinkel


    Full Text Available Inheritance powder is the name that was given to poisons, especially arsenic, that were commonly used in the 17th and early 18th centuries to hasten the death of the elderly. For most of the 17th century, arsenic was deadly but undetectable, making it nearly impossible to prove that someone had been poisoned. The first arsenic test produced a gas—hardly something that a scientist could show to a judge. Faced with a growing epidemic of poisonings, doctors and chemists spent decades searching for something better.(see PDF for full column

  13. Annular pulse column development studies

    International Nuclear Information System (INIS)

    Benedict, G.E.


    The capacity of critically safe cylindrical pulse columns limits the size of nuclear fuel solvent extraction plants because of the limited cross-sectional area of plutonium, U-235, or U-233 processing columns. Thus, there is a need to increase the cross-sectional area of these columns. This can be accomplished through the use of a column having an annular cross section. The preliminary testing of a pilot-plant-scale annular column has been completed and is reported herein. The column is made from 152.4-mm (6-in.) glass pipe sections with an 89-mm (3.5-in.) o.d. internal tube, giving an annular width of 32-mm (1.25-in.). Louver plates are used to swirl the column contents to prevent channeling of the phases. The data from this testing indicate that this approach can successfully provide larger-cross-section critically safe pulse columns. While the capacity is only 70% of that of a cylindrical column of similar cross section, the efficiency is almost identical to that of a cylindrical column. No evidence was seen of any non-uniform pulsing action from one side of the column to the other

  14. Density of oxidation-induced stacking faults in damaged silicon

    NARCIS (Netherlands)

    Kuper, F.G.; Hosson, J.Th.M. De; Verwey, J.F.


    A model for the relation between density and length of oxidation-induced stacking faults on damaged silicon surfaces is proposed, based on interactions of stacking faults with dislocations and neighboring stacking faults. The model agrees with experiments.

  15. TOMS Column Ozone Earth Probe (MODIS Ancillary Data) (United States)

    National Aeronautics and Space Administration — OZONEEP is a daily, gridded 2-D Column Ozone product from the TOMS instrument in ASCII format. It consists of averaged ozone data from 00Z hours to 24Z hours with...

  16. Physically Connected Stacked Patch Antenna Design with 100% Bandwidth

    KAUST Repository

    Klionovski, Kirill


    Typically, stacked patch antennas are parasitically coupled and provide larger bandwidth than a single patch antenna. Here, we show a stacked patch antenna design where square patches with semi-circular cutouts are physically connected to each other. This arrangement provides 100% bandwidth from 23.9–72.2 GHz with consistent high gain (5 dBi or more) across the entire bandwidth. In another variation, a single patch loaded with a superstrate provides 83.5% bandwidth from 25.6–62.3 GHz. The mechanism of bandwidth enhancement is explained through electromagnetic simulations. Measured reflection coefficient, radiation patterns and gain results confirm the extremely wideband performance of the design.

  17. Piezoelectric Multilayer-Stacked Hybrid Actuation/Transduction System (United States)

    Xu, Tian-Bing (Inventor); Jiang, Xiaoning (Inventor); Su, Ji (Inventor)


    A novel full piezoelectric multilayer stacked hybrid actuation/transduction system. The system demonstrates significantly-enhanced electromechanical performance by utilizing the cooperative contributions of the electromechanical responses of multilayer stacked negative and positive strain components. Both experimental and theoretical studies indicate that for this system, the displacement is over three times that of a same-sized conventional flextensional actuator/transducer. The system consists of at least 2 layers which include electromechanically active components. The layers are arranged such that when electric power is applied, one layer contracts in a transverse direction while the second layer expands in a transverse direction which is perpendicular to the transverse direction of the first layer. An alternate embodiment includes a third layer. In this embodiment, the outer two layers contract in parallel transverse directions while the middle layer expands in a transverse direction which is perpendicular to the transverse direction of the outer layers.

  18. Rain Sensor with Stacked Light Waveguide Having Tilted Air Gap

    Directory of Open Access Journals (Sweden)

    Kyoo Nam Choi


    Full Text Available Vehicle sensor to detect rain drop on and above waveguide utilizing light deflection and scattering was realized, keeping wide sensing coverage and sensitivity to detect mist accumulation. Proposed sensor structure under stacked light wave guide consisted of light blocking fixture surrounding photodetector and adjacent light source. Tilted air gap between stacked light waveguide and light blocking fixture played major role to increase sensitivity and to enhance linearity. This sensor structure eliminated complex collimating optics, while keeping wide sensing coverage using simple geometry. Detection algorithm based on time-to-intensity transformation process was used to convert raining intensity into countable raining process. Experimental result inside simulated rain chamber showed distinct different response between light rain and normal rain. Application as automobile rain sensor is expected.

  19. Tunable electro-optic filter stack

    Energy Technology Data Exchange (ETDEWEB)

    Fontecchio, Adam K.; Shriyan, Sameet K.; Bellingham, Alyssa


    A holographic polymer dispersed liquid crystal (HPDLC) tunable filter exhibits switching times of no more than 20 microseconds. The HPDLC tunable filter can be utilized in a variety of applications. An HPDLC tunable filter stack can be utilized in a hyperspectral imaging system capable of spectrally multiplexing hyperspectral imaging data acquired while the hyperspectral imaging system is airborne. HPDLC tunable filter stacks can be utilized in high speed switchable optical shielding systems, for example as a coating for a visor or an aircraft canopy. These HPDLC tunable filter stacks can be fabricated using a spin coating apparatus and associated fabrication methods.

  20. Dynamical stability of slip-stacking particles

    Energy Technology Data Exchange (ETDEWEB)

    Eldred, Jeffrey; Zwaska, Robert


    We study the stability of particles in slip-stacking configuration, used to nearly double proton beam intensity at Fermilab. We introduce universal area factors to calculate the available phase space area for any set of beam parameters without individual simulation. We find perturbative solutions for stable particle trajectories. We establish Booster beam quality requirements to achieve 97% slip-stacking efficiency. We show that slip-stacking dynamics directly correspond to the driven pendulum and to the system of two standing-wave traps moving with respect to each other.

  1. A stochastic view on column efficiency. (United States)

    Gritti, Fabrice


    A stochastic model of transcolumn eddy dispersion along packed beds was derived. It was based on the calculation of the mean travel time of a single analyte molecule from one radial position to another. The exchange mechanism between two radial positions was governed by the transverse dispersion of the analyte across the column. The radial velocity distribution was obtained by flow simulations in a focused-ion-beam scanning electron microscopy (FIB-SEM) based 3D reconstruction from a 2.1 mm × 50 mm column packed with 2 μm BEH-C 18 particles. Accordingly, the packed bed was divided into three coaxial and uniform zones: (1) a 1.4 particle diameter wide, ordered, and loose packing at the column wall (velocity u w ), (2) an intermediate 130 μm wide, random, and dense packing (velocity u i ), and (3) the bulk packing in the center of the column (velocity u c ). First, the validity of this proposed stochastic model was tested by adjusting the predicted to the observed reduced van Deemter plots of a 2.1 mm × 50 mm column packed with 2 μm BEH-C 18 fully porous particles (FPPs). An excellent agreement was found for u i  = 0.93u c , a result fully consistent with the FIB-SEM observation (u i  = 0.95u c ). Next, the model was used to measure u i  = 0.94u c for 2.1 mm × 100 mm column packed with 1.6 μm Cortecs-C 18 superficially porous particles (SPPs). The relative velocity bias across columns packed with SPPs is then barely smaller than that observed in columns packed with FPPs (+6% versus + 7%). u w =1.8u i is measured for a 75 μm × 1 m capillary column packed with 2 μm BEH-C 18 particles. Despite this large wall-to-center velocity bias (+80%), the presence of the thin and ordered wall packing layer has no negative impact on the kinetic performance of capillary columns. Finally, the stochastic model of long-range eddy dispersion explains why analytical (2.1-4.6 mm i.d.) and capillary (columns can all be

  2. Column-to-column packing variation of disposable pre-packed columns for protein chromatography. (United States)

    Schweiger, Susanne; Hinterberger, Stephan; Jungbauer, Alois


    In the biopharmaceutical industry, pre-packed columns are the standard for process development, but they must be qualified before use in experimental studies to confirm the required performance of the packed bed. Column qualification is commonly done by pulse response experiments and depends highly on the experimental testing conditions. Additionally, the peak analysis method, the variation in the 3D packing structure of the bed, and the measurement precision of the workstation influence the outcome of qualification runs. While a full body of literature on these factors is available for HPLC columns, no comparable studies exist for preparative columns for protein chromatography. We quantified the influence of these parameters for commercially available pre-packed and self-packed columns of disposable and non-disposable design. Pulse response experiments were performed on 105 preparative chromatography columns with volumes of 0.2-20ml. The analyte acetone was studied at six different superficial velocities (30, 60, 100, 150, 250 and 500cm/h). The column-to-column packing variation between disposable pre-packed columns of different diameter-length combinations varied by 10-15%, which was acceptable for the intended use. The column-to-column variation cannot be explained by the packing density, but is interpreted as a difference in particle arrangement in the column. Since it was possible to determine differences in the column-to-column performance, we concluded that the columns were well-packed. The measurement precision of the chromatography workstation was independent of the column volume and was in a range of±0.01ml for the first peak moment and±0.007 ml 2 for the second moment. The measurement precision must be considered for small columns in the range of 2ml or less. The efficiency of disposable pre-packed columns was equal or better than that of self-packed columns. Copyright © 2017 The Author(s). Published by Elsevier B.V. All rights reserved.

  3. Wearable solar cells by stacking textile electrodes. (United States)

    Pan, Shaowu; Yang, Zhibin; Chen, Peining; Deng, Jue; Li, Houpu; Peng, Huisheng


    A new and general method to produce flexible, wearable dye-sensitized solar cell (DSC) textiles by the stacking of two textile electrodes has been developed. A metal-textile electrode that was made from micrometer-sized metal wires was used as a working electrode, while the textile counter electrode was woven from highly aligned carbon nanotube fibers with high mechanical strengths and electrical conductivities. The resulting DSC textile exhibited a high energy conversion efficiency that was well maintained under bending. Compared with the woven DSC textiles that are based on wire-shaped devices, this stacked DSC textile unexpectedly exhibited a unique deformation from a rectangle to a parallelogram, which is highly desired in portable electronics. This lightweight and wearable stacked DSC textile is superior to conventional planar DSCs because the energy conversion efficiency of the stacked DSC textile was independent of the angle of incident light. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


    Directory of Open Access Journals (Sweden)

    Eva Mazancová


    Full Text Available Stacking fault energy of high manganese alloys (marked as TWIP and TRIPLEX is an important parameter determining deformation mechanism type realized in above mentioned alloys. Stacking fault energy level can be asserted with a gliding of partial and/or full dislocations, b gliding mechanism and twinning deformation process in connection with increasing of fracture deformation level (deformation elongation and with increasing of simultaneously realized work hardening proces., c gliding mechanism and deformation induced e-martensite formation. In contribution calculated stacking fault energies are presented for various chemical compositions of high manganese alloys. Stacking fault energy dependences on manganese, carbon, iron and alluminium contents are presented. Results are confronted with some accessible papers.The aim of work is to deepen knowledge of presented data. The TWIP and TRIPLEX alloys can be held for promissing new automotive materials.

  5. Stack-Based Typed Assembly Language

    National Research Council Canada - National Science Library

    Morrisett, Greg


    .... This paper also formalizes the typing connection between CPS based compilation and stack based compilation and illustrates how STAL can formally model calling conventions by specifying them as formal translations of source function types to STAL types.

  6. Characterization of Piezoelectric Stacks for Space Applications (United States)

    Sherrit, Stewart; Jones, Christopher; Aldrich, Jack; Blodget, Chad; Bao, Xiaoqi; Badescu, Mircea; Bar-Cohen, Yoseph


    Future NASA missions are increasingly seeking to actuate mechanisms to precision levels in the nanometer range and below. Co-fired multilayer piezoelectric stacks offer the required actuation precision that is needed for such mechanisms. To obtain performance statistics and determine reliability for extended use, sets of commercial PZT stacks were tested in various AC and DC conditions at both nominal and high temperatures and voltages. In order to study the lifetime performance of these stacks, five actuators were driven sinusoidally for up to ten billion cycles. An automated data acquisition system was developed and implemented to monitor each stack's electrical current and voltage waveforms over the life of the test. As part of the monitoring tests, the displacement, impedance, capacitance and leakage current were measured to assess the operation degradation. This paper presents some of the results of this effort.

  7. The stack on software and sovereignty

    CERN Document Server

    Bratton, Benjamin H


    A comprehensive political and design theory of planetary-scale computation proposing that The Stack -- an accidental megastructure -- is both a technological apparatus and a model for a new geopolitical architecture.

  8. Column: File Cabinet Forensics

    Directory of Open Access Journals (Sweden)

    Simson Garfinkel


    Full Text Available Researchers can spend their time reverse engineering, performing reverse analysis, or making substantive contributions to digital forensics science. Although work in all of these areas is important, it is the scientific breakthroughs that are the most critical for addressing the challenges that we face.Reverse Engineering is the traditional bread-and-butter of digital forensics research. Companies like Microsoft and Apple deliver computational artifacts (operating systems, applications and phones to the commercial market. These artifacts are bought and used by billions. Some have evil intent, and (if society is lucky, the computers end up in the hands of law enforcement. Unfortunately the original vendors rarely provide digital forensics tools that make their systems amenable to analysis by law enforcement. Hence the need for reverse engineering.(see PDF for full column

  9. Buckling of a holey column. (United States)

    Pihler-Puzović, D; Hazel, A L; Mullin, T


    We report the results from a combined experimental and numerical investigation of buckling in a novel variant of an elastic column under axial load. We find that including a regular line of centred holes in the column can prevent conventional, global, lateral buckling. Instead, the local microstructure introduced by the holes allows the column to buckle in an entirely different, internal, mode in which the holes are compressed in alternate directions, but the column maintains the lateral reflection symmetry about its centreline. The internal buckling mode can be accommodated within a smaller external space than the global one; and it is the preferred buckling mode over an intermediate range of column lengths for sufficiently large holes. For very short or sufficiently long columns a modification of the classical, global, lateral buckling is dominant.

  10. Stacking for Cosmic Magnetism with SKA Surveys


    Stil, J. M.; Keller, B. W.


    Stacking polarized radio emission in SKA surveys provides statistical information on large samples that is not accessible otherwise due to limitations in sensitivity, source statistics in small fields, and averaging over frequency (including Faraday synthesis). Polarization is a special case because one obvious source of stacking targets is the Stokes I source catalog, possibly in combination with external catalogs, for example an SKA HI survey or a non-radio survey. We point out the signific...

  11. Environmental Modeling Framework using Stacked Gaussian Processes


    Abdelfatah, Kareem; Bao, Junshu; Terejanu, Gabriel


    A network of independently trained Gaussian processes (StackedGP) is introduced to obtain predictions of quantities of interest with quantified uncertainties. The main applications of the StackedGP framework are to integrate different datasets through model composition, enhance predictions of quantities of interest through a cascade of intermediate predictions, and to propagate uncertainties through emulated dynamical systems driven by uncertain forcing variables. By using analytical first an...

  12. Generalized data stacking programming model with applications


    Hala Samir Elhadidy; Rawya Yehia Rizk; Hassen Taher Dorrah


    Recent researches have shown that, everywhere in various sciences the systems are following stacked-based stored change behavior when subjected to events or varying environments “on and above” their normal situations. This paper presents a generalized data stack programming (GDSP) model which is developed to describe the system changes under varying environment. These changes which are captured with different ways such as sensor reading are stored in matrices. Extraction algorithm and identif...

  13. Representations of stack triangulations in the plane


    Selig, Thomas


    Stack triangulations appear as natural objects when defining an increasing family of triangulations by successive additions of vertices. We consider two different probability distributions for such objects. We represent, or "draw" these random stack triangulations in the plane $\\R^2$ and study the asymptotic properties of these drawings, viewed as random compact metric spaces. We also look at the occupation measure of the vertices, and show that for these two distributions it converges to som...

  14. Consistent model driven architecture (United States)

    Niepostyn, Stanisław J.


    The goal of the MDA is to produce software systems from abstract models in a way where human interaction is restricted to a minimum. These abstract models are based on the UML language. However, the semantics of UML models is defined in a natural language. Subsequently the verification of consistency of these diagrams is needed in order to identify errors in requirements at the early stage of the development process. The verification of consistency is difficult due to a semi-formal nature of UML diagrams. We propose automatic verification of consistency of the series of UML diagrams originating from abstract models implemented with our consistency rules. This Consistent Model Driven Architecture approach enables us to generate automatically complete workflow applications from consistent and complete models developed from abstract models (e.g. Business Context Diagram). Therefore, our method can be used to check practicability (feasibility) of software architecture models.

  15. Cortical columns for quick brains


    Stoop, Ralph L.; Saase, Victor; Wagner, Clemens; Stoop, Britta; Stoop, Ruedi


    It is widely believed that the particular wiring observed within cortical columns boosts neural computation. We use rewiring of neural networks performing real-world cognitive tasks to study the validity of this argument. In a vast survey of wirings within the column we detect, however, no traces of the proposed effect. It is on the mesoscopic inter-columnar scale that the existence of columns - largely irrespective of their inner organization - enhances the speed of information transfer and ...

  16. Vertical microreactor stack consist of poly-(tetrafluoroethylene) microfluidics for immunoassay

    International Nuclear Information System (INIS)

    Ukita, Yoshiaki; Kondo, Saki; Utsumi, Yuichi; Takeo, Masahiro; Negoro, Seiji; Kataoka, Chiwa


    This paper reports the first application of high-aspect ratio PTFE microstruscute, which fabricated by synchrotron radiation induced photo-evaporation process, to enzyme-linked immunosorvent assay. The advantages of PTFE microstructure for the development of lab-on-a-chip due to the extremely high-aspect ratio microstructure and chemical stability of PTFE is discussed. The results of immunoassay shows the successful detection of analyte (mouse IgG) with detection range with 0-100ng/ml. This result suggests the successful immobilization of antibody (anti-mouse IgG goat antibody) onto the x-ray exposed surface of PTFE microstructure and successful demonstration of antigen-antibody reaction in the PTFE high-aspect ratio microstructure. We also demonstrated the detection of polychlorinated biphenyl (PCB). As the result of demonstration, we successfully detected PCB with ranging analyte concentration of 0.1-10 ng/ml. (author)

  17. A Time-predictable Stack Cache

    DEFF Research Database (Denmark)

    Abbaspour, Sahar; Brandner, Florian; Schoeberl, Martin


    Real-time systems need time-predictable architectures to support static worst-case execution time (WCET) analysis. One architectural feature, the data cache, is hard to analyze when different data areas (e.g., heap allocated and stack allocated data) share the same cache. This sharing leads to le...... of a cache for stack allocated data. Our port of the LLVM C++ compiler supports the management of the stack cache. The combination of stack cache instructions and the hardware implementation of the stack cache is a further step towards timepredictable architectures.......Real-time systems need time-predictable architectures to support static worst-case execution time (WCET) analysis. One architectural feature, the data cache, is hard to analyze when different data areas (e.g., heap allocated and stack allocated data) share the same cache. This sharing leads to less...... precise results of the cache analysis part of the WCET analysis. Splitting the data cache for different data areas enables composable data cache analysis. The WCET analysis tool can analyze the accesses to these different data areas independently. In this paper we present the design and implementation...

  18. Detailed Electrochemical Characterisation of Large SOFC Stacks

    DEFF Research Database (Denmark)

    Mosbæk, Rasmus Rode; Hjelm, Johan; Barfod, R.


    As solid oxide fuel cell (SOFC) technology is moving closer to a commercial break through, lifetime limiting factors, determination of the limits of safe operation and methods to measure the “state-of-health” of operating cells and stacks are becoming of increasing interest. This requires applica...... out at a range of ac perturbation amplitudes in order to investigate linearity of the response and the signal-to-noise ratio. Separation of the measured impedance into series and polarisation resistances was possible....... to analyse in detail. Today one is forced to use mathematical modelling to extract information about existing gradients and cell resistances in operating stacks, as mature techniques for local probing are not available. This type of spatially resolved information is essential for model refinement...... and validation, and helps to further the technological stack development. Further, more detailed information obtained from operating stacks is essential for developing appropriate process monitoring and control protocols for stack and system developers. An experimental stack with low ohmic resistance from Topsoe...

  19. Supervised Learning in Hyper-Column Model


    島田, 敬士; 鶴田, 直之; 谷口, 倫一郎


    In this paper, we propose a supervised learning method in Hyper-Column Model (HCM). HCM is a model to recognize images, and consists of Hierarchical Self-Organizing Maps (HSOM) and Neocognitron (NC). HCM complements disadvantages of HSOM and NC, and inherits advantages from them. There is a problem, however, that HCM does not suit general image recognition in HCM since its learning method is an unsupervised one with competitive learning which is used by Self-Organizing Map (SOM). Therefore...

  20. Classifier Subset Selection for the Stacked Generalization Method Applied to Emotion Recognition in Speech (United States)

    Álvarez, Aitor; Sierra, Basilio; Arruti, Andoni; López-Gil, Juan-Miguel; Garay-Vitoria, Nestor


    In this paper, a new supervised classification paradigm, called classifier subset selection for stacked generalization (CSS stacking), is presented to deal with speech emotion recognition. The new approach consists of an improvement of a bi-level multi-classifier system known as stacking generalization by means of an integration of an estimation of distribution algorithm (EDA) in the first layer to select the optimal subset from the standard base classifiers. The good performance of the proposed new paradigm was demonstrated over different configurations and datasets. First, several CSS stacking classifiers were constructed on the RekEmozio dataset, using some specific standard base classifiers and a total of 123 spectral, quality and prosodic features computed using in-house feature extraction algorithms. These initial CSS stacking classifiers were compared to other multi-classifier systems and the employed standard classifiers built on the same set of speech features. Then, new CSS stacking classifiers were built on RekEmozio using a different set of both acoustic parameters (extended version of the Geneva Minimalistic Acoustic Parameter Set (eGeMAPS)) and standard classifiers and employing the best meta-classifier of the initial experiments. The performance of these two CSS stacking classifiers was evaluated and compared. Finally, the new paradigm was tested on the well-known Berlin Emotional Speech database. We compared the performance of single, standard stacking and CSS stacking systems using the same parametrization of the second phase. All of the classifications were performed at the categorical level, including the six primary emotions plus the neutral one. PMID:26712757

  1. Annex I.G. Demolition of the G1 stack at Marcoule by toppling

    International Nuclear Information System (INIS)


    The G1 stack at Marcoule was constructed during the first half of 1956 as a ventilation outlet for the G1 reactor, which is cooled by air. After the G1 reactor was decommissioned, the G1 stack served as a ventilation outlet for two new nuclear facilities on the site. Being no longer in compliance with regulations and having many inadequacies and uncertainties in terms of the prestressed concrete, the stack posed a potential damage risk in extreme wind or in the event of an earthquake. In 1994 it was decided that a new stack would be built to act as an outlet for the existing nuclear facilities, and that the old one would be demolished. The G1 stack was 100 m in height, 10 m in diameter and constructed with 24 vertically stacked concrete rings consisting of nine prefabricated sections, each 3.6 m in height. It was capped by a metal deflector (about 6 m in height and weighing 50 t). The inside consisted of nine semicircular tubes constructed of steel sheet metal weighing 120 t. The base of the stack consisted of the foundation, a plate and a base plate which were constructed at the site. The barrel sections were prefabricated. Construction lasted from January 1956 to June 1956. At the base, the cylindrical portion of the stack widened to form three feet extending to a depth of 7.5 m. The base plate of the stack was formed onsite to the height of 16.7 m and then prestressed using cables. A repair carried out in 1964 included adding a concrete lining of the initial rings of the cylinder up to a level of 22.1 m. Additional prestressing with the base plate and repair of the horizontal and vertical prestressing of the barrel were also carried out, leaving only 22 rings and 43 visible cables. The total mass of the stack was 2170 t, including: - Concrete: cylinder 800 t, base plate 1200 t; - Steel: internal structures 120 t, deflector 50 t. The main radiological risk was the presence of traces of tritium. The radioactive inventory for the entire stack was estimated in 2000

  2. Calculated stacking-fault energies of elemental metals

    DEFF Research Database (Denmark)

    Rosengaard, N. M.; Skriver, Hans Lomholt


    We have performed ab initio calculations of twin, intrinsic, and extrinsic face-centered-cubic stacking faults for all the 3d, 4d, and 5d transition metals by means of a Green's-function technique, based on the linear-muffin-tin-orbitals method within the tight-binding and atomic-sphere approxima......We have performed ab initio calculations of twin, intrinsic, and extrinsic face-centered-cubic stacking faults for all the 3d, 4d, and 5d transition metals by means of a Green's-function technique, based on the linear-muffin-tin-orbitals method within the tight-binding and atomic......-sphere approximations. The results are in excellent agreement with recent layer Korringa-Kohn-Rostoker Green's-function calculations where stacking-fault energies for Ni, Cu, Rh, Pd, Ag, Ir, and Au were found by means of the the so-called force theorem. We find that the self-consistent fault energies for all the metals...... on the local atomic coordination are obeyed to a high degree of accuracy....

  3. 296-B-10 stack monitoring and sampling system annual system assessment report

    International Nuclear Information System (INIS)

    Ridge, T.M.


    B Plant Administration Manual, requires an annual system assessment to evaluate and report the present condition of the sampling and monitoring system associated with stack 296-B-10 at B Plant. The ventilation system of WESF (Waste Encapsulation and Storage Facility) is designed to provide airflow patterns so that air movement throughout the building is from areas of lesser radioactivity to areas of greater radioactivity. All potentially contaminated areas are maintained at a negative pressure with respect to the atmosphere so that air flows into the building at all times. The exhaust discharging through the 296-B-10 stack is continuously monitored and sampled using a sampling and monitoring probe assembly located approximately 17.4 meters (57 feet) above the base of the stack. The probe assembly consists of 5 nozzles for the sampling probe and 2 nozzles to monitor the flow. The sampling and monitoring system associated with Stack 296-B-10 is functional and performing satisfactorily

  4. Segmentation of RGB-D indoor scenes by stacking random forests and conditional random fields

    DEFF Research Database (Denmark)

    Thøgersen, Mikkel; Guerrero, Sergio Escalera; Gonzàlez, Jordi


    on stacked classifiers; the benefits are two fold: on one hand, the system scales well to consider different types of complex features and, on the other hand, the use of stacked classifiers makes the performance of the proposed technique more accurate. The proposed method consists of a random forest using...... a stacked random forest which gives the final predictions. The model is tested on the renown NYU-v2 dataset and the recently available SUNRGBD dataset. The approach shows that simple multimodal features with the power of using multi-class multi-scale stacked sequential learners (MMSSL) can achieve slight...... better performance than state of the art methods on the same dataset. The results show an improvement of 2.3% over the base model by using MMSSL and displays that the method is effective in this problem domain....

  5. From Multi to Single Stack Automata (United States)

    Atig, Mohamed Faouzi

    We investigate the issue of reducing the verification problem of multi-stack machines to the one for single-stack machines. For instance, elegant (and practically efficient) algorithms for bounded-context switch analysis of multi-pushdown systems have been recently defined based on reductions to the reachability problem of (single-stack) pushdown systems [10,18]. In this paper, we extend this view to both bounded-phase visibly pushdown automata (BVMPA) [16] and ordered multi-pushdown automata (OMPA) [1] by showing that each of their emptiness problem can be reduced to the one for a class of single-stack machines. For these reductions, we introduce effective generalized pushdown automata (EGPA) where operations on stacks are (1) pop the top symbol of the stack, and (2) push a word in some (effectively) given set of words L over the stack alphabet, assuming that L is in some class of languages for which checking whether L intersects regular languages is decidable. We show that the automata-based saturation procedure for computing the set of predecessors in standard pushdown automata can be extended to prove that for EGPA too the set of all predecessors of a regular set of configurations is an effectively constructible regular set. Our reductions from OMPA and BVMPA to EGPA, together with the reachability analysis procedure for EGPA, allow to provide conceptually simple algorithms for checking the emptiness problem for each of these models, and to significantly simplify the proofs for their 2ETIME upper bounds (matching their lower-bounds).

  6. Start-Stop Test Procedures on the PEMFC Stack Level

    DEFF Research Database (Denmark)

    Mitzel, Jens; Nygaard, Frederik; Veltzé, Sune

    The test is addressed to investigate the influence on stack durability of a long stop followed by a restart of a stack. Long stop should be defined as a stop in which the anodic compartment is fully filled by air due to stack leakages. In systems, leakage level of the stack is low and time to fil...

  7. EmuStack: An OpenStack-Based DTN Network Emulation Platform (Extended Version

    Directory of Open Access Journals (Sweden)

    Haifeng Li


    Full Text Available With the advancement of computing and network virtualization technology, the networking research community shows great interest in network emulation. Compared with network simulation, network emulation can provide more relevant and comprehensive details. In this paper, EmuStack, a large-scale real-time emulation platform for Delay Tolerant Network (DTN, is proposed. EmuStack aims at empowering network emulation to become as simple as network simulation. Based on OpenStack, distributed synchronous emulation modules are developed to enable EmuStack to implement synchronous and dynamic, precise, and real-time network emulation. Meanwhile, the lightweight approach of using Docker container technology and network namespaces allows EmuStack to support a (up to hundreds of nodes large-scale topology with only several physical nodes. In addition, EmuStack integrates the Linux Traffic Control (TC tools with OpenStack for managing and emulating the virtual link characteristics which include variable bandwidth, delay, loss, jitter, reordering, and duplication. Finally, experiences with our initial implementation suggest the ability to run and debug experimental network protocol in real time. EmuStack environment would bring qualitative change in network research works.

  8. Levitation characteristics of HTS tape stacks

    Energy Technology Data Exchange (ETDEWEB)

    Pokrovskiy, S. V.; Ermolaev, Y. S.; Rudnev, I. A. [National Research Nuclear University MEPhI (Moscow Engineering Physics Institute), Moscow (Russian Federation)


    Due to the considerable development of the technology of second generation high-temperature superconductors and a significant improvement in their mechanical and transport properties in the last few years it is possible to use HTS tapes in the magnetic levitation systems. The advantages of tapes on a metal substrate as compared with bulk YBCO material primarily in the strength, and the possibility of optimizing the convenience of manufacturing elements of levitation systems. In the present report presents the results of the magnetic levitation force measurements between the stack of HTS tapes containing of tapes and NdFeB permanent magnet in the FC and ZFC regimes. It was found a non- linear dependence of the levitation force from the height of the array of stack in both modes: linear growth at small thickness gives way to flattening and constant at large number of tapes in the stack. Established that the levitation force of stacks comparable to that of bulk samples. The numerical calculations using finite element method showed that without the screening of the applied field the levitation force of the bulk superconductor and the layered superconductor stack with a critical current of tapes increased by the filling factor is exactly the same, and taking into account the screening force slightly different.

  9. Forced Air-Breathing PEMFC Stacks

    Directory of Open Access Journals (Sweden)

    K. S. Dhathathreyan


    Full Text Available Air-breathing fuel cells have a great potential as power sources for various electronic devices. They differ from conventional fuel cells in which the cells take up oxygen from ambient air by active or passive methods. The air flow occurs through the channels due to concentration and temperature gradient between the cell and the ambient conditions. However developing a stack is very difficult as the individual cell performance may not be uniform. In order to make such a system more realistic, an open-cathode forced air-breathing stacks were developed by making appropriate channel dimensions for the air flow for uniform performance in a stack. At CFCT-ARCI (Centre for Fuel Cell Technology-ARC International we have developed forced air-breathing fuel cell stacks with varying capacity ranging from 50 watts to 1500 watts. The performance of the stack was analysed based on the air flow, humidity, stability, and so forth, The major advantage of the system is the reduced number of bipolar plates and thereby reduction in volume and weight. However, the thermal management is a challenge due to the non-availability of sufficient air flow to remove the heat from the system during continuous operation. These results will be discussed in this paper.

  10. Contemporary sample stacking in analytical electrophoresis. (United States)

    Malá, Zdena; Šlampová, Andrea; Křivánková, Ludmila; Gebauer, Petr; Boček, Petr


    This contribution is a methodological review of the publications about the topic from the last 2 years. Therefore, it is primarily organized according to the methods and procedures used in surveyed papers and the origin and type of sample and specification of analytes form the secondary structure. The introductory part about navigation in the architecture of stacking brings a brief characterization of the various stacking methods, with the description of mutual links to each other and important differences among them. The main body of the article brings a survey of publications organized according to main principles of stacking and then according to the origin and type of the sample. Provided that the paper cited gave explicitly the relevant data, information about the BGE(s) used, procedure, detector employed, and reached LOD and/or concentration effect is given. The papers where the procedure used is a combination of diverse fragments and parts of various stacking techniques are mentioned in a special section on combined techniques. The concluding remarks in the final part of the review evaluate present state of art and the trends of sample stacking in CE. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Enhanced dynamical stability with harmonic slip stacking

    Directory of Open Access Journals (Sweden)

    Jeffrey Eldred


    Full Text Available We develop a configuration of radio-frequency (rf cavities to dramatically improve the performance of slip stacking. Slip stacking is an accumulation technique used at Fermilab to nearly double proton intensity by maintaining two beams of different momenta in the same storage ring. The two particle beams are longitudinally focused in the Recycler by two 53 MHz 100 kV rf cavities with a small frequency difference between them. We propose an additional 106 MHz 20 kV rf cavity with a frequency at the double the average of the upper and lower main rf frequencies. We show the harmonic rf cavity cancels out the resonances generated between the two main rf cavities and we derive the relationship between the harmonic rf voltage and the main rf voltage. We find the area factors that can be used to calculate the available phase space area for any set of beam parameters without individual simulation. We establish Booster beam quality requirements to achieve 99% slip stacking efficiency. We measure the longitudinal distribution of the Booster beam and use it to generate a realistic beam model for slip stacking simulation. We demonstrate that the harmonic rf cavity can not only reduce particle loss during slip stacking, but also reduce the final longitudinal emittance.

  12. Stacking fault tetrahedra formation in the neighbourhood of grain boundaries

    CERN Document Server

    Samaras, M; Van Swygenhoven, H; Victoria, M


    Large scale molecular dynamics computer simulations are performed to study the role of the grain boundary (GB) during the cascade evolution in irradiated nanocrystalline Ni. At all primary knock-on atom (PKA) energies in cascades near GBs, the damage produced after cooling down is vacancy dominated. Truncated stacking fault tetrahedra (TSFTs) are easily formed at 10 keV and higher PKA energies. At the higher energies a complex partial dislocation network forms, consisting of TSFTs. The GB acts as an interstitial sink without undergoing major structural changes.

  13. Nanocomposite Materials of Alternately Stacked C60 Monolayer and Graphene

    International Nuclear Information System (INIS)

    Ishikawa, M.; Miura, K.; Kamiya, S.; Yoshimoto, S.; Suzuki, M.; Kuwahara, D.; Sasaki, N.


    We synthesized the novel nanocomposite consisting alternately of a stacked single graphene sheet and a C 60 monolayer by using the graphite intercalation technique in which alkylamine molecules help intercalate large C 60 molecules into the graphite. Moreover, it is found that the intercalated C 60 molecules can rotate in between single graphene sheets by using C 13 NMR measurements. This preparation method provides a general way for intercalating huge fullerene molecules into graphite, which will lead to promising materials with novel mechanical, physical, and electrical properties.

  14. Nanocomposite Materials of Alternately Stacked C60 Monolayer and Graphene

    Directory of Open Access Journals (Sweden)

    Makoto Ishikawa


    Full Text Available We synthesized the novel nanocomposite consisting alternately of a stacked single graphene sheet and a C60 monolayer by using the graphite intercalation technique in which alkylamine molecules help intercalate large C60 molecules into the graphite. Moreover, it is found that the intercalated C60 molecules can rotate in between single graphene sheets by using C13 NMR measurements. This preparation method provides a general way for intercalating huge fullerene molecules into graphite, which will lead to promising materials with novel mechanical, physical, and electrical properties.

  15. Partial Path Column Generation for the Vehicle Routing Problem

    DEFF Research Database (Denmark)

    Jepsen, Mads Kehlet; Petersen, Bjørn

    This paper presents a column generation algorithm for the Capacitated Vehicle Routing Problem (CVRP) and the Vehicle Routing Problem with Time Windows (VRPTW). Traditionally, column generation models of the CVRP and VRPTW have consisted of a Set Partitioning master problem with each column...... of the giant tour’; a so-called partial path, i.e., not necessarily starting and ending in the depot. This way, the length of the partial path can be bounded and a better control of the size of the solution space for the pricing problem can be obtained....

  16. Progress of MCFC stack technology at Toshiba

    Energy Technology Data Exchange (ETDEWEB)

    Hori, M.; Hayashi, T.; Shimizu, Y. [Toshiba Corp., Tokyo (Japan)


    Toshiba is working on the development of MCFC stack technology; improvement of cell characteristics, and establishment of separator technology. For the cell technology, Toshiba has concentrated on both the restraints of NiO cathode dissolution and electrolyte loss from cells, which are the critical issues to extend cell life in MCFC, and great progress has been made. On the other hand, recognizing that the separator is one of key elements in accomplishing reliable and cost-competitive MCFC stacks, Toshiba has been accelerating the technology establishment and verification of an advanced type separator. A sub-scale stack with such a separator was provided for an electric generating test, and has been operated for more than 10,000 hours. This paper presents several topics obtained through the technical activities in the MCFC field at Toshiba.

  17. Column-Oriented Database Systems (Tutorial)

    NARCIS (Netherlands)

    D. Abadi; P.A. Boncz (Peter); S. Harizopoulos


    textabstractColumn-oriented database systems (column-stores) have attracted a lot of attention in the past few years. Column-stores, in a nutshell, store each database table column separately, with attribute values belonging to the same column stored contiguously, compressed, and densely packed, as


    Directory of Open Access Journals (Sweden)

    Nelson López


    Full Text Available In this research, the nonlinear behavior of a real-scale experimental joint (node is studied, consisting of three reinforced concrete elements, one column and two beams joined to a structural steel column at the upper level. In the numerical analysis the model of the union was analyzed in the inelastic range, this model was elaborated with the finite element program based on fibers, SeismoStruct to analyze as a function of time, the traction and compression efforts in the confined area and not confined area of the concrete column and in the longitudinal reinforcement steel, as well as verification of the design of the base plate that joins the two columns. The results showed that tensile stresses in the unconfined zone surpassed the concrete breaking point, with cracking occurring just below the lower edge of the beams; in the confined area the traction efforts were much lower, with cracks occurring later than in the non-confined area. The concrete column-steel column joint behaved as a rigid node, so the elastic design was consistent with the calculation methodology of base plates for steel columns.

  19. Design Handbook for a Stack Foundation


    Tuominen, Vilma


    This thesis was made for Citec Engineering Oy Ab as a handbook and as a design tool for concrete structure designers. Handbook is about the Wärtsilä Power Plant stack structure, which is a base for about 40 meters high stack pipe. The purpose is to make a calculation base to support the design work, which helps the designer to check the right dimensions of the structure. Thesis is about to be for the concrete designers and also other designers and authorities. As an example I have used an...

  20. Simple model of stacking-fault energies

    DEFF Research Database (Denmark)

    Stokbro, Kurt; Jacobsen, Lærke Wedel


    A simple model for the energetics of stacking faults in fcc metals is constructed. The model contains third-nearest-neighbor pairwise interactions and a term involving the fourth moment of the electronic density of states. The model is in excellent agreement with recently published local-density ......A simple model for the energetics of stacking faults in fcc metals is constructed. The model contains third-nearest-neighbor pairwise interactions and a term involving the fourth moment of the electronic density of states. The model is in excellent agreement with recently published local...

  1. Fluid Dynamic Experiments on Mush Column Magmatism (United States)

    Flanagan-Brown, R. E.; Marsh, B. D.


    A vertically extensive stack of sills interconnected by pipe-like conduits extending from the mantle through the lithosphere and capped by a volcanic center is a magmatic mush column. At any instant at various locations it contains fractionated and primitive melts as pools of nearly crystal-free magma, pools of crystal-rich magma, thick beds of cumulates, open conduits, and conduits congested by cognate and wall debris. All boundaries of the system are sheathed by solidification fronts. With the wide range of local, characteristic length scales there is a commensurate range of solidification time scales. This creates a complicated series of resistances to magma flow and provides a variety of distinct local physical environments for the chemical modification of magma. The system is driven by over-pressure from the addition of new melt from below. The over-pressure propagates upward by moving magma which flushes conduits, disrupts cumulate beds, and pools or purges sills. A critical aspect of this process is the entrainment, transport, and deposition of crystals throughout the system. Picritic lavas charges with entrained (tramp) olivine of a wide compositional range erupted at many systems (e.g. Jan Mayen, Kilauea, Reunion, etc.) are the final expression of this process. That the size and abundance of these crystals is correlated with eruptive flux (Murata & Richter, AJS, 1966) suggests an important indicator of the overall dynamics of the mush column. A mush column of this basic nature is observed is observed in the McMurdo Dry Valleys region of Antarctica and is inferred beneath Hawaii and the ocean ridges. We have attempted to model this process by studying the entrainment, transport, and deposition of particles in a vertical stack of sills (Plexiglas tanks) connected by resistive conduits (check valves), over-pressured from the base, and open at the top. The system is about two meters in height with water and oil as fluids and particles with Reynolds numbers

  2. Geometrically Consistent Mesh Modification

    KAUST Repository

    Bonito, A.


    A new paradigm of adaptivity is to execute refinement, coarsening, and smoothing of meshes on manifolds with incomplete information about their geometry and yet preserve position and curvature accuracy. We refer to this collectively as geometrically consistent (GC) mesh modification. We discuss the concept of discrete GC, show the failure of naive approaches, and propose and analyze a simple algorithm that is GC and accuracy preserving. © 2010 Society for Industrial and Applied Mathematics.

  3. Water Column Sonar Data Collection (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The collection and analysis of water column sonar data is a relatively new avenue of research into the marine environment. Primary uses include assessing biological...

  4. Contemporary sample stacking in analytical electrophoresis

    Czech Academy of Sciences Publication Activity Database

    Šlampová, Andrea; Malá, Zdeňka; Pantůčková, Pavla; Gebauer, Petr; Boček, Petr


    Roč. 34, č. 1 (2013), s. 3-18 ISSN 0173-0835 R&D Projects: GA ČR GAP206/10/1219 Institutional support: RVO:68081715 Keywords : biological samples * stacking * trace analysis * zone electrophoresis Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 3.161, year: 2013

  5. SRS reactor stack plume marking tests

    International Nuclear Information System (INIS)

    Petry, S.F.


    Tests performed in 105-K in 1987 and 1988 demonstrated that the stack plume can successfully be made visible (i.e., marked) by introducing smoke into the stack breech. The ultimate objective of these tests is to provide a means during an emergency evacuation so that an evacuee can readily identify the stack plume and evacuate in the opposite direction, thus minimizing the potential of severe radiation exposure. The EPA has also requested DOE to arrange for more tests to settle a technical question involving the correct calculation of stack downwash. New test canisters were received in 1988 designed to produce more smoke per unit time; however, these canisters have not been evaluated, because normal ventilation conditions have not been reestablished in K Area. Meanwhile, both the authorization and procedure to conduct the tests have expired. The tests can be performed during normal reactor operation. It is recommended that appropriate authorization and procedure approval be obtained to resume testing after K Area restart

  6. Testing of Electrodes, Cells and Short Stacks

    DEFF Research Database (Denmark)

    Hauch, Anne; Mogensen, Mogens Bjerg


    The present contribution describes the electrochemical testing and characterization of electrodes, cells, and short stacks. To achieve the maximum insight and results from testing of electrodes and cells, it is obviously necessary to have a good understanding of the fundamental principles...

  7. Stack Gas Scrubber Makes the Grade (United States)

    Chemical and Engineering News, 1975


    Describes a year long test of successful sulfur dioxide removal from stack gas with a calcium oxide slurry. Sludge disposal problems are discussed. Cost is estimated at 0.6 mill per kwh not including sludge removal. A flow diagram and equations are included. (GH)

  8. OpenStack Object Storage (Swift) essentials

    CERN Document Server

    Kapadia, Amar; Varma, Sreedhar


    If you are an IT administrator and you want to enter the world of cloud storage using OpenStack Swift, then this book is ideal for you. Basic knowledge of Linux and server technology is beneficial to get the most out of the book.

  9. Stacked spheres and lower bound theorem

    Indian Academy of Sciences (India)



    Nov 20, 2011 ... Preliminaries. Lower bound theorem. On going work. Definitions. An n-simplex is a convex hull of n + 1 affinely independent points. (called vertices) in some Euclidean space R. N . Stacked spheres and lower bound theorem. Basudeb Datta. Indian Institute of Science. 2 / 27 ...

  10. Contemporary sample stacking in analytical electrophoresis

    Czech Academy of Sciences Publication Activity Database

    Malá, Zdeňka; Šlampová, Andrea; Křivánková, Ludmila; Gebauer, Petr; Boček, Petr


    Roč. 36, č. 1 (2015), s. 15-35 ISSN 0173-0835 R&D Projects: GA ČR(CZ) GA13-05762S Institutional support: RVO:68081715 Keywords : biological samples * stacking * trace analysis * zone electrophoresis Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 2.482, year: 2015

  11. The data type variety of stack algebras

    NARCIS (Netherlands)

    Bergstra, J.A.; Tucker, J.V.


    We define and study the class of all stack algebras as the class of all minimal algebras in a variety defined by an infinite recursively enumerable set of equations. Among a number of results, we show that the initial model of the variety is computable, that its equational theory is decidable,

  12. Photoswitchable Intramolecular H-Stacking of Perylenebisimide

    NARCIS (Netherlands)

    Wang, Jiaobing; Kulago, Artem; Browne, Wesley R.; Feringa, Ben L.


    Dynamic control over the formation of H- or J-type aggregates of chromophores is of fundamental importance for developing responsive organic optoelectronic materials. In this study, the first example of photoswitching between a nonstacked and an intramolecularly H-stacked arrangement of

  13. 40 CFR 61.53 - Stack sampling. (United States)


    ... 40 Protection of Environment 8 2010-07-01 2010-07-01 false Stack sampling. 61.53 Section 61.53 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL... sampling. (a) Mercury ore processing facility. (1) Unless a waiver of emission testing is obtained under...

  14. 40 CFR 61.33 - Stack sampling. (United States)


    ... 40 Protection of Environment 8 2010-07-01 2010-07-01 false Stack sampling. 61.33 Section 61.33 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL... sampling. (a) Unless a waiver of emission testing is obtained under § 61.13, each owner or operator...

  15. OpenStack cloud computing cookbook

    CERN Document Server

    Jackson, Kevin


    A Cookbook full of practical and applicable recipes that will enable you to use the full capabilities of OpenStack like never before.This book is aimed at system administrators and technical architects moving from a virtualized environment to cloud environments with familiarity of cloud computing platforms. Knowledge of virtualization and managing linux environments is expected.

  16. Behavior of Confined Columns under Different Techniques


    Mostafa Osman; Ata El-Kareim Shoeib Soliman


    Since columns are the most important elements of the structures, failure of one column in a critical location can cause a progressive collapse. In this respect, the repair and strengthening of columns is a very important subject to reduce the building failure and to keep the columns capacity. Twenty columns with different parameters is tested and analysis. Eleven typical confined reinforced concrete (RC) columns with different types of techniques are assessment. And also,...

  17. The Rucio Consistency Service

    CERN Document Server

    Serfon, Cedric; The ATLAS collaboration


    One of the biggest challenge with Large scale data management system is to ensure the consistency between the global file catalog and what is physically on all storage elements. To tackle this issue, the Rucio software which is used by the ATLAS Distributed Data Management system has been extended to automatically handle lost or unregistered files (aka Dark Data). This system automatically detects these inconsistencies and take actions like recovery or deletion of unneeded files in a central manner. In this talk, we will present this system, explain the internals and give some results.

  18. Reporting consistently on CSR

    DEFF Research Database (Denmark)

    Thomsen, Christa; Nielsen, Anne Ellerup


    This chapter first outlines theory and literature on CSR and Stakeholder Relations focusing on the different perspectives and the contextual and dynamic character of the CSR concept. CSR reporting challenges are discussed and a model of analysis is proposed. Next, our paper presents the results...... in the reporting material. By implementing consistent discourse strategies that interact according to a well-defined pattern or order, it is possible to communicate a strong social commitment on the one hand, and to take into consideration the expectations of the shareholders and the other stakeholders...

  19. When is holography consistent?

    Directory of Open Access Journals (Sweden)

    Brett McInnes


    Full Text Available Holographic duality relates two radically different kinds of theory: one with gravity, one without. The very existence of such an equivalence imposes strong consistency conditions which are, in the nature of the case, hard to satisfy. Recently a particularly deep condition of this kind, relating the minimum of a probe brane action to a gravitational bulk action (in a Euclidean formulation, has been recognized; and the question arises as to the circumstances under which it, and its Lorentzian counterpart, is satisfied. We discuss the fact that there are physically interesting situations in which one or both versions might, in principle, not be satisfied. These arise in two distinct circumstances: first, when the bulk is not an Einstein manifold and, second, in the presence of angular momentum. Focusing on the application of holography to the quark–gluon plasma (of the various forms arising in the early Universe and in heavy-ion collisions, we find that these potential violations never actually occur. This suggests that the consistency condition is a “law of physics” expressing a particular aspect of holography.

  20. Profile consistency on TFTR

    International Nuclear Information System (INIS)

    Fredrickson, E.D.; McGuire, K.M.; Goldston, R.J.


    Electron heat transport on TFTR and other tokamaks is several orders of magnitude larger than neoclassical calculations predict. Despite considerable effort, there is still no clear theoretical understanding of this anomalous transport. The electron temperature profile, T e (r), has shown a marked consistency on many machines for a wide range of plasma parameters and heating profiles. This could be an important clue as to the process responsible for this enhanced thermal transport. In the first section of the paper the result is presented that TFTR electron temperature profile shapes are even more constrained than previous models of profile consistency suggested. The profile shapes, T e (r)/T e (a/2), are found to be invariant (for r>0.4 a) for a wide range of parameters, including q(a). In the second section, an experiment is discussed which uses a fast current ramp to transiently decouple the current density profile, J(r), and the T e (r) profiles. From this experiment, it has been determined that the J(r) profile can be strongly modified with no measureable effect on the electron temperature profile shape. Thus, while the electron temperature profile is apparently constrained, the current profile is not. (author). Letter-to-the-editor. 25 refs, 9 figs

  1. The Influence of Stack Position and Acoustic Frequency on the Performance of Thermoacoustic Refrigerator with the Standing Wave

    Directory of Open Access Journals (Sweden)

    Kajurek Jakub


    Full Text Available Thermoacoustic refrigerator uses acoustic power to transport heat from a low-temperature source to a high-temperature source. The increasing interest in thermoacoustic technology is caused due to its simplicity, reliability as well as application of environmentally friendly working fluids. A typical thermoacoustic refrigerator consists of a resonator, a stack of parallel plates, two heat exchangers and a source of acoustic wave. The article presents the influence of the stack position in the resonance tube and the acoustic frequency on the performance of thermoacoustic refrigerator with a standing wave driven by a loudspeaker, which is measured in terms of the temperature difference between the stack edges. The results from experiments, conducted for the stack with the plate spacing 0.3 mm and the length 50 mm, acoustic frequencies varying between 100 and 400 Hz and air as a working fluid are consistent with the theory presented in this paper. The experiments confirmed that the temperature difference for the stack with determined plate spacing depends on the acoustic frequency and the stack position. The maximum values were achieved for resonance frequencies and the stack position between the pressure and velocity node.

  2. Partial path column generation for the vehicle routing problem with time windows

    DEFF Research Database (Denmark)

    Petersen, Bjørn; Jepsen, Mads Kehlet


    This paper presents a column generation algorithm for the Vehicle Routing Problem with Time Windows (VRPTW). Traditionally, column generation models of the VRPTW have consisted of a Set Partitioning master problem with each column representing a route, i.e., a resource feasible path starting...... number of customers. We suggest to relax that ‘each column is a route’ into ‘each column is a part of the giant tour’; a so-called partial path, i.e., not necessarily starting and ending in the depot. This way, the length of the partial path can be bounded and a better control of the size of the solution...

  3. Performance evaluation of a rectifier column using gamma column scanning

    Directory of Open Access Journals (Sweden)

    Aquino Denis D.


    Full Text Available Rectifier columns are considered to be a critical component in petroleum refineries and petrochemical processing installations as they are able to affect the overall performance of these facilities. It is deemed necessary to monitor the operational conditions of such vessels to optimize processes and prevent anomalies which could pose undesired consequences on product quality that might lead to huge financial losses. A rectifier column was subjected to gamma scanning using a 10-mCi Co-60 source and a 2-inch-long detector in tandem. Several scans were performed to gather information on the operating conditions of the column under different sets of operating parameters. The scan profiles revealed unexpected decreases in the radiation intensity at vapour levels between trays 2 and 3, and between trays 4 and 5. Flooding also occurred during several scans which could be attributed to parametric settings.

  4. Short steel and concrete columns under high temperatures

    Directory of Open Access Journals (Sweden)

    A. E. P. G. A. Jacintho

    Full Text Available The growing demand for knowledge about the effect of high temperatures on structures has stimulated increasing research worldwide. This article presents experimental results for short composite steel and concrete columns subjected to high temperatures in ovens with or without an axial compression load, numerically analyzes the temperature distribution in these columns after 30 and 60 minutes and compares them with experimental results. The models consist of concrete-filled tubes of three different thicknesses and two different diameters, and the concrete fill has conventional properties that remained constant for all of the models. The stress-strain behavior of the composite columns was altered after exposure to high temperatures relative to the same columns at room temperature, which was most evident in the 60-minute tests due to the higher temperatures reached. The computational analysis adopted temperature rise curves that were obtained experimentally.

  5. Project W-420 Stack Monitoring system upgrades conceptual design report

    Energy Technology Data Exchange (ETDEWEB)

    TUCK, J.A.


    This document describes the scope, justification, conceptual design, and performance of Project W-420 stack monitoring system upgrades on six NESHAP-designated, Hanford Tank Farms ventilation exhaust stacks.

  6. Heuristic Solution Approaches to the Double TSP with Multiple Stacks

    DEFF Research Database (Denmark)

    Petersen, Hanne Løhmann

    This paper introduces the Double Travelling Salesman Problem with Multiple Stacks and presents a three different metaheuristic approaches to its solution. The Double Travelling Salesman Problem with Multiple Stacks is concerned with finding the shortest route performing pickups and deliveries...

  7. Heuristic Solution Approaches to the Double TSP with Multiple Stacks

    DEFF Research Database (Denmark)

    Petersen, Hanne Løhmann


    This paper introduces the Double Travelling Salesman Problem with Multiple Stacks and presents a three different metaheuristic approaches to its solution. The Double Travelling Salesman Problem with Multiple Stacks is concerned with finding the shortest route performing pickups and deliveries...

  8. External magnetic field and self-field effects in stacked long Josephson junctions

    DEFF Research Database (Denmark)

    Carapella, G.; Costabile, G.; Mygind, Jesper


    We have fabricated and tested samples consisting of two long stacked Josephson junctions with direct access to the intermediate electrode, whose thickness is smaller than London penetration depth lambda(L). The electrodes are patterned so that the junctions can be independently biased in the over...

  9. Experimental Evidence for Phase-Locked States in Stacked Long Josephson Junctions

    DEFF Research Database (Denmark)

    Carapella, Giovanni; Costabile, Giovanni; Mancher, Martin


    We fabricated and tested samples consisteing of two long stacked Josephson junctions with direct access to the intermediate electrode, whose thickness is smaller than the London penetration depth $\\lambda _L$. The electrodes are patterned so that the junctions can be idependently biased in the ov...

  10. Post column derivatisation analyses review. Is post-column derivatisation incompatible with modern HPLC columns? (United States)

    Jones, Andrew; Pravadali-Cekic, Sercan; Dennis, Gary R; Shalliker, R Andrew


    Post Column derivatisation (PCD) coupled with high performance liquid chromatography or ultra-high performance liquid chromatography is a powerful tool in the modern analytical laboratory, or at least it should be. One drawback with PCD techniques is the extra post-column dead volume due to reaction coils used to enable adequate reaction time and the mixing of reagents which causes peak broadening, hence a loss of separation power. This loss of efficiency is counter-productive to modern HPLC technologies, -such as UHPLC. We reviewed 87 PCD methods published from 2009 to 2014. We restricted our review to methods published between 2009 and 2014, because we were interested in the uptake of PCD methods in UHPLC environments. Our review focused on a range of system parameters including: column dimensions, stationary phase and particle size, as well as the geometry of the reaction loop. The most commonly used column in the methods investigated was not in fact a modern UHPLC version with sub-2-micron, (or even sub-3-micron) particles, but rather, work-house columns, such as, 250 × 4.6 mm i.d. columns packed with 5 μm C18 particles. Reaction loops were varied, even within the same type of analysis, but the majority of methods employed loop systems with volumes greater than 500 μL. A second part of this review illustrated briefly the effect of dead volume on column performance. The experiment evaluated the change in resolution and separation efficiency of some weak to moderately retained solutes on a 250 × 4.6 mm i.d. column packed with 5 μm particles. The data showed that reaction loops beyond 100 μL resulted in a very serious loss of performance. Our study concluded that practitioners of PCD methods largely avoid the use of UHPLC-type column formats, so yes, very much, PCD is incompatible with the modern HPLC column. Copyright © 2015. Published by Elsevier B.V.

  11. DEVS Models of Palletized Ground Stacking in Storeyed Grain Warehouse

    Directory of Open Access Journals (Sweden)

    Hou Shu-Yi


    Full Text Available Processed grain stored in storeyed warehouse is generally stacked on the ground without pallets. However, in order to improve the storing way, we developed a new stacking method, palletized ground stacking. Simulation should be used to present this new storing way. DEVS provides a formalized way to describe the system model. In this paper, DEVS models of palletized ground stacking in storeyed grain warehouse are given and a simulation model is developed by AutoMod.

  12. Synthesis and characterization of straight and stacked-sheet AlN nanowires with high purity

    International Nuclear Information System (INIS)

    Lei, M.; Yang, H.; Li, P.G.; Tang, W.H.


    Large-scale AlN nanowires with hexagonal crystal structure were synthesized by the direct nitridation method at high temperatures. The experimental results indicate that these single-crystalline AlN nanowires have high purity and consist of straight and stacked-sheet nanowires. It is found that straight AlN nanowire grows along [1, 1, -2, 0] direction, whereas the stacked-sheet nanowire with hexagonal cross section is along [0 0 0 1] direction. It is thought that vapor-solid (VS) mechanism should be responsible for the growth of AlN nanowires

  13. Robust naphthyl methacrylate monolithic column for high performance liquid chromatography of a wide range of solutes. (United States)

    Jonnada, Murthy; El Rassi, Ziad


    An organic monolithic column based on the co-polymerization of 2-naphthyl methacrylate (NAPM) as the functional monomer and trimethylolpropane trimethacrylate (TRIM) as the crosslinker was introduced for high performance reversed-phase liquid chromatography (RPC). The co-polymerization was performed in situ in a stainless steel column of 4.6mm i.d. in the presence of a ternary porogen consisting of 1-dodecanol and cyclohexanol. This monolithic column (referred to as naphthyl methacrylate monolithic column or NMM column) showed high mechanical stability at relatively high mobile phase flow velocity indicating that the column has excellent hydrodynamic characteristics. To characterize the NMM column, different probe molecules including alkyl benzenes, and aniline, benzene, toluene and phenol derivatives were chromatographed on the column and the results in terms of k, selectivity and plate counts were compared to those obtained on an octadecyl silica (ODS) column in order to assess the presence of π-π and hydrophobic interactions on the NMM column under otherwise the same elution conditions. The NMM column offered additional π-π interactions with aromatic molecules in addition to hydrophobic interactions under RPC elution conditions. Run-to-run and column-to-column reproducibility of solute k values were evaluated, and percent relative standard deviation of column using shallow (30min at 1.0mL/min), steep (10min at 1.0mL/min) and ultra steep (1min at 3.0mL/min) linear gradient elution at increasing ACN concentration in the mobile phase using a 10cm×4.6mm i.d. column in case of shallow and steep linear gradients and a 3cm×4.6mm i.d. column for ultra steep linear gradient. Copyright © 2015 Elsevier B.V. All rights reserved.

  14. Notes on G-theory of Deligne-Mumford stacks


    Toen, B.


    Based on the methods used by the author to prove the Riemann-Roch formula for algebraic stacks, this paper contains a description of the rationnal G-theory of Deligne-Mumford stacks over general bases. We will use these results to study equivariant K-theory, and also to define new filtrations on K-theory of algebraic stacks.

  15. Learning algorithms for stack filter classifiers

    Energy Technology Data Exchange (ETDEWEB)

    Porter, Reid B [Los Alamos National Laboratory; Hush, Don [Los Alamos National Laboratory; Zimmer, Beate G [TEXAS A& M


    Stack Filters define a large class of increasing filter that is used widely in image and signal processing. The motivations for using an increasing filter instead of an unconstrained filter have been described as: (1) fast and efficient implementation, (2) the relationship to mathematical morphology and (3) more precise estimation with finite sample data. This last motivation is related to methods developed in machine learning and the relationship was explored in an earlier paper. In this paper we investigate this relationship by applying Stack Filters directly to classification problems. This provides a new perspective on how monotonicity constraints can help control estimation and approximation errors, and also suggests several new learning algorithms for Boolean function classifiers when they are applied to real-valued inputs.

  16. Industrial stacks design; Diseno de chimeneas industriales

    Energy Technology Data Exchange (ETDEWEB)

    Cacheux, Luis [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)


    The Instituto de Investigaciones Electricas (IIE) though its Civil Works Department, develops, under contract with CFE`s Gerencia de Proyectos Termoelectricos (Management of Fossil Power Plant Projects), a series of methods for the design of stacks, which pretends to solve the a present day problem: the stack design of the fossil power plants that will go into operation during the next coming years in the country. [Espanol] El Instituto de Investigaciones Electricas (IIE), a traves del Departamento de Ingenieria Civil, desarrolla, bajo contrato con la Gerencia de Proyectos Termoelectricos, de la Comision Federal de Electricidad (CFE), un conjunto de metodos para el diseno de chimeneas, con el que se pretende resolver un problema inmediato: el diseno de las chimeneas de las centrales termoelectricas que entraran en operacion durante los proximos anos, en el pais.

  17. Annular feed air breathing fuel cell stack (United States)

    Wilson, Mahlon S.


    A stack of polymer electrolyte fuel cells is formed from a plurality of unit cells where each unit cell includes fuel cell components defining a periphery and distributed along a common axis, where the fuel cell components include a polymer electrolyte membrane, an anode and a cathode contacting opposite sides of the membrane, and fuel and oxygen flow fields contacting the anode and the cathode, respectively, wherein the components define an annular region therethrough along the axis. A fuel distribution manifold within the annular region is connected to deliver fuel to the fuel flow field in each of the unit cells. In a particular embodiment, a single bolt through the annular region clamps the unit cells together. In another embodiment, separator plates between individual unit cells have an extended radial dimension to function as cooling fins for maintaining the operating temperature of the fuel cell stack.

  18. System for inspection of stacked cargo containers (United States)

    Derenzo, Stephen [Pinole, CA


    The present invention relates to a system for inspection of stacked cargo containers. One embodiment of the invention generally comprises a plurality of stacked cargo containers arranged in rows or tiers, each container having a top, a bottom a first side, a second side, a front end, and a back end; a plurality of spacers arranged in rows or tiers; one or more mobile inspection devices for inspecting the cargo containers, wherein the one or more inspection devices are removeably disposed within the spacers, the inspection means configured to move through the spacers to detect radiation within the containers. The invented system can also be configured to inspect the cargo containers for a variety of other potentially hazardous materials including but not limited to explosive and chemical threats.

  19. Multistage Force Amplification of Piezoelectric Stacks (United States)

    Xu, Tian-Bing (Inventor); Siochi, Emilie J. (Inventor); Zuo, Lei (Inventor); Jiang, Xiaoning (Inventor); Kang, Jin Ho (Inventor)


    Embodiments of the disclosure include an apparatus and methods for using a piezoelectric device, that includes an outer flextensional casing, a first cell and a last cell serially coupled to each other and coupled to the outer flextensional casing such that each cell having a flextensional cell structure and each cell receives an input force and provides an output force that is amplified based on the input force. The apparatus further includes a piezoelectric stack coupled to each cell such that the piezoelectric stack of each cell provides piezoelectric energy based on the output force for each cell. Further, the last cell receives an input force that is the output force from the first cell and the last cell provides an output apparatus force In addition, the piezoelectric energy harvested is based on the output apparatus force. Moreover, the apparatus provides displacement based on the output apparatus force.

  20. Radiation-Tolerant Intelligent Memory Stack - RTIMS (United States)

    Ng, Tak-kwong; Herath, Jeffrey A.


    This innovation provides reconfigurable circuitry and 2-Gb of error-corrected or 1-Gb of triple-redundant digital memory in a small package. RTIMS uses circuit stacking of heterogeneous components and radiation shielding technologies. A reprogrammable field-programmable gate array (FPGA), six synchronous dynamic random access memories, linear regulator, and the radiation mitigation circuits are stacked into a module of 42.7 42.7 13 mm. Triple module redundancy, current limiting, configuration scrubbing, and single- event function interrupt detection are employed to mitigate radiation effects. The novel self-scrubbing and single event functional interrupt (SEFI) detection allows a relatively soft FPGA to become radiation tolerant without external scrubbing and monitoring hardware

  1. Absorption spectra of AA-stacked graphite

    International Nuclear Information System (INIS)

    Chiu, C W; Lee, S H; Chen, S C; Lin, M F; Shyu, F L


    AA-stacked graphite shows strong anisotropy in geometric structures and velocity matrix elements. However, the absorption spectra are isotropic for the polarization vector on the graphene plane. The spectra exhibit one prominent plateau at middle energy and one shoulder structure at lower energy. These structures directly reflect the unique geometric and band structures and provide sufficient information for experimental fitting of the intralayer and interlayer atomic interactions. On the other hand, monolayer graphene shows a sharp absorption peak but no shoulder structure; AA-stacked bilayer graphene has two absorption peaks at middle energy and abruptly vanishes at lower energy. Furthermore, the isotropic features are expected to exist in other graphene-related systems. The calculated results and the predicted atomic interactions could be verified by optical measurements.

  2. Development of on-site PAFC stacks

    Energy Technology Data Exchange (ETDEWEB)

    Hotta, K.; Matsumoto, Y. [Kansai Electric Power Co., Amagasaki (Japan); Horiuchi, H.; Ohtani, T. [Mitsubishi Electric Corp., Kobe (Japan)


    PAFC (Phosphoric Acid Fuel Cell) has been researched for commercial use and demonstration plants have been installed in various sites. However, PAFC don`t have a enough stability yet, so more research and development must be required in the future. Especially, cell stack needs a proper state of three phases (liquid, gas and solid) interface. It is very difficult technology to keep this condition for a long time. In the small size cell with the electrode area of 100 cm{sup 2}, gas flow and temperature distributions show uniformity. But in the large size cell with the electrode area of 4000 cm{sup 2}, the temperature distributions show non-uniformity. These distributions would cause to be shorten the cell life. Because these distributions make hot-spot and gas poverty in limited parts. So we inserted thermocouples in short-stack for measuring three-dimensional temperature distributions and observed effects of current density and gas utilization on temperature.

  3. CAM and stack air sampler design guide

    International Nuclear Information System (INIS)

    Phillips, T.D.


    About 128 air samplers and CAMs presently in service to detect and document potential radioactive release from 'H' and 'F' area tank farm ventilation stacks are scheduled for replacement and/or upgrade by Projects S-5764, S-2081, S-3603, and S-4516. The seven CAMs scheduled to be upgraded by Project S-4516 during 1995 are expected to provide valuable experience for the three remaining projects. The attached document provides design guidance for the standardized High Level Waste air sampling system

  4. Contemporary sample stacking in analytical electrophoresis

    Czech Academy of Sciences Publication Activity Database

    Malá, Zdeňka; Gebauer, Petr; Boček, Petr


    Roč. 32, č. 1 (2011), s. 116-126 ISSN 0173-0835 R&D Projects: GA ČR GA203/08/1536; GA ČR GAP206/10/1219; GA AV ČR IAA400310703 Institutional research plan: CEZ:AV0Z40310501 Keywords : biological samples * stacking * trace analysis * zone electrophoresis Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 3.303, year: 2011

  5. Stacked Switched Capacitor Energy Buffer Architecture


    Chen, Minjie; Perreault, David J.; Afridi, Khurram


    Electrolytic capacitors are often used for energy buffering applications, including buffering between single-phase ac and dc. While these capacitors have high energy density compared to film and ceramic capacitors, their life is limited. This paper presents a stacked switched capacitor (SSC) energy buffer architecture and some of its topological embodiments, which when used with longer life film capacitors overcome this limitation while achieving effective energy densities comparable to elect...

  6. Evaluation of a stack: A concrete chimney with brick liner

    International Nuclear Information System (INIS)

    Joshi, J.R.; Amin, J.A.; Porthouse, R.A.


    A 200 ft. tall stack, consisting of a concrete chimney with an independent acid proof brick liner built in the 1950's, serving the Separations facility at the Savannah River Site (SRS), was evaluated for the performance category 3 (PC3) level of Natural Phenomena Hazards (NPH) effects. The inelastic energy absorption capacity of the concrete chimney was considered in the evaluation of the earthquake resistance, in particular, to compute the F μ factor. The calculated value of F μ exceeded 3.0, while the seismic demand for the PC3 level, using an F μ value of 1.5, was found to be less than the capacity of the concrete chimney. The capacity formulation of ACI 307 was modified to incorporate the effect of an after design opening on the tension side. There are considerable uncertainties in determining the earthquake resistance of the independent brick liner. The critical liner section, located at the bottom of the breeching opening, does not meet the current recommendations. A discussion is provided for the possible acceptable values for the ''Moment Reduction Factor'', R w or F μ for the liner. Comments are provided on the comparison of stack demands using response spectra (RS) versus time history (TH) analysis, with and without soil structure interaction (SSI) effects

  7. Complete intrinsic coincident polarimetry using stacked organic photovoltaics (United States)

    Gupta Roy, S.; Awartani, O. M.; Sen, P.; O'Connor, B. T.; Kudenov, M. W.


    Measuring the 2 dimensional Stokes vector, to determine the polarization state of light, finds application in multiple areas, including the characterization of aerosol size distributions, target identification, quality control by evaluating the distribution of stress birefringence, resolving data channels in telecommunications, and for evaluating biological tissues in medical imaging. Conventional methods, such as channeled and division of focal plane polarimeters, usually limit spatial resolution, while others, like division of aperture or division of amplitude polarimeters, have higher complexity and less compactness. To help solve these issues, we have developed a system that uses semitransparent organic photovoltaics (OPVs) as photodetectors. The active area of the devices consist of biaxially oriented polymer films, which enables the device to preferentially absorb certain polarized states of incident light, depending on the orientation of the polymer chains. Taking advantage of the cells' transparency and ease of processing, compared to inorganic materials, enables multiple devices to be "stacked" along the optical axis. Presently, experiments have been conducted to detect linear polarization states of light. We use three stacked OPVs, where each device can measure one of the first three Stokes parameters simultaneously, thereby ensuring high spatial and temporal resolution with inherent spatial registration. In this paper, the fabrication of the OPVs and the design and calibration technique is documented, along with experimental data, supporting the hypothesis.

  8. Column properties and flow profiles of a flat, wide column for high-pressure liquid chromatography. (United States)

    Mriziq, Khaled S; Guiochon, Georges


    The design and the construction of a pressurized, flat, wide column for high-performance liquid chromatography (HPLC) are described. This apparatus, which is derived from instruments that implement over-pressured thin layer chromatography, can carry out only uni-dimensional chromatographic separations. However, it is intended to be the first step in the development of more powerful instruments that will be able to carry out two-dimensional chromatographic separations, in which case, the first separation would be a space-based separation, LC(x), taking place along one side of the bed and the second separation would be a time-based separation, LC(t), as in classical HPLC but proceeding along the flat column, not along a tube. The apparatus described consists of a pressurization chamber made of a Plexiglas block and a column chamber made of stainless steel. These two chambers are separated by a thin Mylar membrane. The column chamber is a cavity which is filled with a thick layer (ca. 1mm) of the stationary phase. Suitable solvent inlet and outlet ports are located on two opposite sides of the sorbent layer. The design allows the preparation of a homogenous sorbent layer suitable to be used as a chromatographic column, the achievement of effective seals of the stationary phase layer against the chamber edges, and the homogenous flow of the mobile phase along the chamber. The entire width of the sorbent layer area can be used to develop separations or elute samples. The reproducible performance of the apparatus is demonstrated by the chromatographic separations of different dyes. This instrument is essentially designed for testing detector arrays to be used in a two-dimensional LC(x) x LC(t) instrument. The further development of two-dimension separation chromatographs based on the apparatus described is sketched.

  9. When is stacking confusing? The impact of confusion on stacking in deep H I galaxy surveys (United States)

    Jones, Michael G.; Haynes, Martha P.; Giovanelli, Riccardo; Papastergis, Emmanouil


    We present an analytic model to predict the H I mass contributed by confused sources to a stacked spectrum in a generic H I survey. Based on the ALFALFA (Arecibo Legacy Fast ALFA) correlation function, this model is in agreement with the estimates of confusion present in stacked Parkes telescope data, and was used to predict how confusion will limit stacking in the deepest Square Kilometre Array precursor H I surveys. Stacking with LADUMA (Looking At the Distant Universe with MeerKAT) and DINGO UDEEP (Deep Investigation of Neutral Gas Origins - Ultra Deep) data will only be mildly impacted by confusion if their target synthesized beam size of 10 arcsec can be achieved. Any beam size significantly above this will result in stacks that contain a mass in confused sources that is comparable to (or greater than) that which is detectable via stacking, at all redshifts. CHILES (COSMOS H I Large Extragalactic Survey) 5 arcsec resolution is more than adequate to prevent confusion influencing stacking of its data, throughout its bandpass range. FAST (Five hundred metre Aperture Spherical Telescope) will be the most impeded by confusion, with H I surveys likely becoming heavily confused much beyond z = 0.1. The largest uncertainties in our model are the redshift evolution of the H I density of the Universe and the H I correlation function. However, we argue that the two idealized cases we adopt should bracket the true evolution, and the qualitative conclusions are unchanged regardless of the model choice. The profile shape of the signal due to confusion (in the absence of any detection) was also modelled, revealing that it can take the form of a double Gaussian with a narrow and wide component.

  10. Thyristor stack for pulsed inductive plasma generation. (United States)

    Teske, C; Jacoby, J; Schweizer, W; Wiechula, J


    A thyristor stack for pulsed inductive plasma generation has been developed and tested. The stack design includes a free wheeling diode assembly for current reversal. Triggering of the device is achieved by a high side biased, self supplied gate driver unit using gating energy derived from a local snubber network. The structure guarantees a hard firing gate pulse for the required high dI/dt application. A single fiber optic command is needed to achieve a simultaneous turn on of the thyristors. The stack assembly is used for switching a series resonant circuit with a ringing frequency of 30 kHz. In the prototype pulsed power system described here an inductive discharge has been generated with a pulse duration of 120 micros and a pulse energy of 50 J. A maximum power transfer efficiency of 84% and a peak power of 480 kW inside the discharge were achieved. System tests were performed with a purely inductive load and an inductively generated plasma acting as a load through transformer action at a voltage level of 4.1 kV, a peak current of 5 kA, and a current switching rate of 1 kA/micros.

  11. Electrochemical Detection in Stacked Paper Networks. (United States)

    Liu, Xiyuan; Lillehoj, Peter B


    Paper-based electrochemical biosensors are a promising technology that enables rapid, quantitative measurements on an inexpensive platform. However, the control of liquids in paper networks is generally limited to a single sample delivery step. Here, we propose a simple method to automate the loading and delivery of liquid samples to sensing electrodes on paper networks by stacking multiple layers of paper. Using these stacked paper devices (SPDs), we demonstrate a unique strategy to fully immerse planar electrodes by aqueous liquids via capillary flow. Amperometric measurements of xanthine oxidase revealed that electrochemical sensors on four-layer SPDs generated detection signals up to 75% higher compared with those on single-layer paper devices. Furthermore, measurements could be performed with minimal user involvement and completed within 30 min. Due to its simplicity, enhanced automation, and capability for quantitative measurements, stacked paper electrochemical biosensors can be useful tools for point-of-care testing in resource-limited settings. © 2015 Society for Laboratory Automation and Screening.

  12. A stacked sequential learning method for investigator name recognition from web-based medical articles (United States)

    Zhang, Xiaoli; Zou, Jie; Le, Daniel X.; Thoma, George


    "Investigator Names" is a newly required field in MEDLINE citations. It consists of personal names listed as members of corporate organizations in an article. Extracting investigator names automatically is necessary because of the increasing volume of articles reporting collaborative biomedical research in which a large number of investigators participate. In this paper, we present an SVM-based stacked sequential learning method in a novel application - recognizing named entities such as the first and last names of investigators from online medical journal articles. Stacked sequential learning is a meta-learning algorithm which can boost any base learner. It exploits contextual information by adding the predicted labels of the surrounding tokens as features. We apply this method to tag words in text paragraphs containing investigator names, and demonstrate that stacked sequential learning improves the performance of a nonsequential base learner such as an SVM classifier.

  13. Design and analysis of the PBFA-Z vacuum insulator stack

    International Nuclear Information System (INIS)

    Shoup, R.W.; Long, F.; Martin, T.H.; Stygar, W.A.; Spielman, R.B.; Struve, K.W.; Mostrom, M.; Corcoran, P.; Smith, I.


    Sandia is developing PBFA-Z, a 20-MA driver for z-pinch experiments by replacing the water lines, insulator stack, and MITLs on PBFA II with new hardware. The design of the vacuum insulator stack was dictated by the drive voltage, the electric field stress and grading requirements, the water line and MITL interface requirements, and the machine operations and maintenance requirements. The insulator stack will consist of four separate modules, each of a different design because of different voltage drive and hardware interface requirements. The shape of the components in each module, i.e., grading rings, insulator rings, flux excluders, anode and cathode conductors, and the design of the water line and MITL interfaces, were optimized by using the electrostatic analysis codes, ELECTRO and JASON. The time-dependent performance of the insulator stack was evaluated using IVORY, a 2-D PIC code. The insulator stack design and present the results of the ELECTRO and IVORY analyses are described. (author). 2 tabs., 9 figs., 3 refs

  14. Stack and area tritium monitoring systems for the tokamak fusion test reactor (TFTR)

    International Nuclear Information System (INIS)

    Pearson, G.G.; Meixler, L.D.; Sirsingh, R.A.P.


    This paper reports on the TFTR Tritium Stack and Area Monitoring Systems which have been developed to provide the required level of reliability in a cost effective manner consistent with the mission of the Tritium Handling System on TFTR. Personnel protection, environmental responsibility, and tritium containing system integrity have been the considerations in system design. During the Deuterium-Tritium (D-T) experiments on TFTR, tritium will be used for the first time as one of the fuels. Area monitors provide surveillance of the air in various rooms at TFTR. Stack monitors monitor the air at the TFTR test site that is exhausted through the HVAC systems, from the room exhaust stacks and the tritium systems process vents. The philosophies for the implementation of the Stack and Area Tritium Monitoring Systems at TFTR are to use hardwired controls wherever personnel protection is involved, and to take advantage of modern intelligent controllers to provide a distributed system to support the functions of tracking, displaying, and archiving concentration levels of tritium for all of the monitored areas and stacks

  15. High power multiple wavelength diode laser stack for DPSSL application without temperature control (United States)

    Hou, Dong; Yin, Xia; Wang, Jingwei; Chen, Shi; Zhan, Yun; Li, Xiaoning; Fan, Yingmin; Liu, Xingsheng


    High power diode laser stack is widely used in pumping solid-state laser for years. Normally an integrated temperature control module is required for stabilizing the output power of solid-state laser, as the output power of the solid-state laser highly depends on the emission wavelength and the wavelength shift of diode lasers according to the temperature changes. However the temperature control module is inconvenient for this application, due to its large dimension, high electric power consumption and extra adding a complicated controlling system. Furthermore, it takes dozens of seconds to stabilize the output power when the laser system is turned on. In this work, a compact hard soldered high power conduction cooled diode laser stack with multiple wavelengths is developed for stabilizing the output power of solid-state laser in a certain temperature range. The stack consists of 5 laser bars with the pitch of 0.43mm. The peak output power of each bar in the diode laser stack reaches as much as 557W and the combined lasing wavelength spectrum profile spans 15nm. The solidstate laser, structured with multiple wavelength diode laser stacks, allows the ambient temperature change of 65°C without suddenly degrading the optical performance.

  16. Online estimation of internal stack temperatures in solid oxide fuel cell power generating units (United States)

    Dolenc, B.; Vrečko, D.; Juričić, Ɖ.; Pohjoranta, A.; Pianese, C.


    Thermal stress is one of the main factors affecting the degradation rate of solid oxide fuel cell (SOFC) stacks. In order to mitigate the possibility of fatal thermal stress, stack temperatures and the corresponding thermal gradients need to be continuously controlled during operation. Due to the fact that in future commercial applications the use of temperature sensors embedded within the stack is impractical, the use of estimators appears to be a viable option. In this paper we present an efficient and consistent approach to data-driven design of the estimator for maximum and minimum stack temperatures intended (i) to be of high precision, (ii) to be simple to implement on conventional platforms like programmable logic controllers, and (iii) to maintain reliability in spite of degradation processes. By careful application of subspace identification, supported by physical arguments, we derive a simple estimator structure capable of producing estimates with 3% error irrespective of the evolving stack degradation. The degradation drift is handled without any explicit modelling. The approach is experimentally validated on a 10 kW SOFC system.

  17. Guanine base stacking in G-quadruplex nucleic acids (United States)

    Lech, Christopher Jacques; Heddi, Brahim; Phan, Anh Tuân


    G-quadruplexes constitute a class of nucleic acid structures defined by stacked guanine tetrads (or G-tetrads) with guanine bases from neighboring tetrads stacking with one another within the G-tetrad core. Individual G-quadruplexes can also stack with one another at their G-tetrad interface leading to higher-order structures as observed in telomeric repeat-containing DNA and RNA. In this study, we investigate how guanine base stacking influences the stability of G-quadruplexes and their stacked higher-order structures. A structural survey of the Protein Data Bank is conducted to characterize experimentally observed guanine base stacking geometries within the core of G-quadruplexes and at the interface between stacked G-quadruplex structures. We couple this survey with a systematic computational examination of stacked G-tetrad energy landscapes using quantum mechanical computations. Energy calculations of stacked G-tetrads reveal large energy differences of up to 12 kcal/mol between experimentally observed geometries at the interface of stacked G-quadruplexes. Energy landscapes are also computed using an AMBER molecular mechanics description of stacking energy and are shown to agree quite well with quantum mechanical calculated landscapes. Molecular dynamics simulations provide a structural explanation for the experimentally observed preference of parallel G-quadruplexes to stack in a 5′–5′ manner based on different accessible tetrad stacking modes at the stacking interfaces of 5′–5′ and 3′–3′ stacked G-quadruplexes. PMID:23268444

  18. Significance of Iron(II,III) Hydroxycarbonate Green Rust in Arsenic Remediation Using Zerovalent Iron in Laboratory Column Tests (United States)

    We examined the corrosion products of zerovalent iron used in three column tests for removing arsenic from water under dynamic flow conditions. Each column test lasted three- to four-months using columns consisting of a 10.3-cm depth of 50 : 50 (w : w, Peerless iron : sand) in t...

  19. Role of SiC substrate surface on local tarnishing of deposited silver mirror stacks (United States)

    Limam, Emna; Maurice, Vincent; Seyeux, Antoine; Zanna, Sandrine; Klein, Lorena H.; Chauveau, Grégory; Grèzes-Besset, Catherine; Savin De Larclause, Isabelle; Marcus, Philippe


    The role of the SiC substrate surface on the resistance to the local initiation of tarnishing of thin-layered silver stacks for demanding space mirror applications was studied by combined surface and interface analysis on model stack samples deposited by cathodic magnetron sputtering and submitted to accelerated aging in gaseous H2S. It is shown that suppressing the surface pores resulting from the bulk SiC material production process by surface pretreatment eliminates the high aspect ratio surface sites that are imperfectly protected by the SiO2 overcoat after the deposition of silver. The formation of channels connecting the silver layer to its environment through the failing protection layer at the surface pores and locally enabling H2S entry and Ag2S growth as columns until emergence at the stack surface is suppressed, which markedly delays tarnishing initiation and thereby preserves the optical performance. The results revealed that residual tarnishing initiation proceeds by a mechanism essentially identical in nature but involving different pathways short circuiting the protection layer and enabling H2S ingress until the silver layer. These permeation pathways are suggested to be of microstructural origin and could correspond to the incompletely coalesced intergranular boundaries of the SiO2 layer.

  20. Bubble columns : Structures or stability?

    NARCIS (Netherlands)

    Harteveld, W.K.


    The aim of the thesis is to contribute to the understanding of the hydrodynamics of the gravity driven bubbly flow that can be found in bubble columns. Special attention is paid to the large scale structures that have a strong impact on several key parameters such as the degree of mixing, mass and

  1. Modeling and analysis of conventional and heat-integrated distillation columns

    DEFF Research Database (Denmark)

    Bisgaard, Thomas; Huusom, Jakob Kjøbsted; Abildskov, Jens


    properties of two different heat-integrated distillation column (HIDiC) schemes and the mechanical vapor recompression column. The second case study exemplifies the difference between a HIDiC and a conventional distillation column in the composition profiles within a multicomponent separation, whereas......A generic model that can cover diabatic and adiabatic distillation column configurations is presented, with the aim ofproviding a consistent basis for comparison of alternative distillation column technologies. Both a static and a dynamic formulation of the model, together with a model catalogue...... consisting of the conventional, the heat-integrated and the mechanical vapor recompression distillation columns are presented. The solution procedure of the model is outlined and illustrated in three case studies. One case study being a benchmark study demonstrating the size of the model and the static...

  2. Refinement of numerical models and parametric study of SOFC stack performance (United States)

    Burt, Andrew C.

    The presence of multiple air and fuel channels per fuel cell and the need to combine many cells in series result in complex steady-state temperature distributions within Solid Oxide Fuel Cell (SOFC) stacks. Flow distribution in these channels, when non-uniform, has a significant effect on cell and stack performance. Large SOFC stacks are very difficult to model using full 3-D CFD codes because of the resource requirements needed to solve for the many scales involved. Studies have shown that implementations based on Reduced Order Methods (ROM), if calibrated appropriately, can provide simulations of stacks consisting of more than 20 cells with reasonable computational effort. A pseudo 2-D SOFC stack model capable of studying co-flow and counter-flow cell geometries was developed by solving multiple 1-D SOFC single cell models in parallel on a Beowulf cluster. In order to study cross-flow geometries a novel Multi-Component Multi-Physics (MCMP) scheme was instantiated to produce a Reduced Order 3-D Fuel Cell Model. A C++ implementation of the MCMP scheme developed in this study utilized geometry, control volume, component, and model structures allowing each physical model to be solved only for those components for which it is relevant. Channel flow dynamics were solved using a 1-D flow model to reduce computational effort. A parametric study was conducted to study the influence of mass flow distribution, radiation, and stack size on fuel cell stack performance. Using the pseudo 2-D planar SOFC stack model with stacks of various sizes from 2 to 40 cells it was shown that, with adiabatic wall conditions, the asymmetry of the individual cell can produce a temperature distribution where high and low temperatures are found in the top and bottom cells, respectively. Heat transfer mechanisms such as radiation were found to affect the reduction of the temperature gradient near the top and bottom cell. Results from the reduced order 3-D fuel cell model showed that greater

  3. Independent determination of the accuracy of the OSTR stack gas monitor and its operational application

    International Nuclear Information System (INIS)

    Pickett, B.D.; Johnson, A.G.


    This study was undertaken to determine the accuracy of the stack gas monitor, using techniques which were independent of the monitoring system itself. Samples of argon-41 to be used as the standards in this study were carefully produced in the thermal column of the OSTR and counted on a Ge(Li) detector which was connected to a multichannel analyzer (MCA). As the argon-41 standard in the gas sample flask decayed, the concentration of the argon-41 was compared to the output of the Ge(Li)/MCA system. This established a calibration curve for the counting system, whereby a sample with an unknown concentration of argon-41 could be counted and the subsequent count rate from the sample converted to a concentration expressed in mCi per milliliter. Gas samples were extracted from various points in the reactor exhaust system and the concentrations of argon-41 were determined by counting on the Ge(Li)/MCA system. Each sample concentration was then compared to the argon-41 concentration indicated by the stack gas monitor. The initial results indicated that, although possibly intermittent, the argon-41 concentrations displayed by the stack gas monitor were often approximately 50% of those predicted by analysis of individual samples from the exhaust system. Several possible sources for the discrepancy were checked, including the method of SGM calibration, uneven mixing of exhaust air and argon-41 in the reactor building exhaust stream, and dilution of the gas concentration in the SGM system by air leakage into the system. After considerable effort, the latter cause was found to be the culprit, due to an aging gasket around the stack monitor's moving particulate-filter-paper housing

  4. Improved Direct Methanol Fuel Cell Stack (United States)

    Wilson, Mahlon S.; Ramsey, John C.


    A stack of direct methanol fuel cells exhibiting a circular footprint. A cathode and anode manifold, tie-bolt penetrations and tie-bolts are located within the circular footprint. Each fuel cell uses two graphite-based plates. One plate includes a cathode active area that is defined by serpentine channels connecting the inlet and outlet cathode manifold. The other plate includes an anode active area defined by serpentine channels connecting the inlet and outlet of the anode manifold, where the serpentine channels of the anode are orthogonal to the serpentine channels of the cathode. Located between the two plates is the fuel cell active region.

  5. NSF tandem stack support structure deflection characteristics

    International Nuclear Information System (INIS)

    Cook, J.


    Results are reported of load tests carried out on the glass legs of the insulating stack of the 30 MV tandem Van de Graaff accelerator now under construction at Daresbury Laboratory. The tests to investigate the vulnerability of the legs when subjected to tensile stresses were designed to; establish the angle of rotation of the pads from which the stresses in the glass legs may be calculated, proof-test the structure and at the same time reveal any asymmetry in pad rotations or deflections, and to confirm the validity of the computer design analysis. (UK)

  6. Compliant Glass Seals for SOFC Stacks

    Energy Technology Data Exchange (ETDEWEB)

    Chou, Yeong -Shyung [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Choi, Jung-Pyung [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Xu, Wei [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Stephens, Elizabeth V. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Koeppel, Brian J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Stevenson, Jeffry W. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Lara-Curzio, Edgar [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)


    This report summarizes results from experimental and modeling studies performed by participants in the Solid-State Energy Conversion Alliance (SECA) Core Technology Program, which indicate that compliant glass-based seals offer a number of potential advantages over conventional seals based on de-vitrifying glasses, including reduced stresses during stack operation and thermal cycling, and the ability to heal micro-damage induced during thermal cycling. The properties and composition of glasses developed and/or investigated in these studies are reported, along with results from long-term (up to 5,800h) evaluations of seals based on a compliant glass containing ceramic particles or ceramic fibers.

  7. Effects of combustible stacking in large compartments

    DEFF Research Database (Denmark)

    Gentili, Filippo; Giuliani, Luisa; Bontempi, Franco


    This paper focuses on the modelling of fire in case of various distributions of combustible materials in a large compartment. Large compartments often represent a challenge for structural fire safety, because of lack of prescriptive rules to follow and difficulties of taking into account the effect...... to different stacking configurations of the pallets with the avail of a CFD code. The results in term of temperatures of the hot gasses and of the steel elements composing the structural system are compared with simplified analytical model of localized and post-flashover fires, with the aim of highlighting...

  8. Displacive phase transformations and generalized stacking faults

    Czech Academy of Sciences Publication Activity Database

    Paidar, Václav; Ostapovets, Andriy; Duparc, O. H.; Khalfallah, O.


    Roč. 122, č. 3 (2012), s. 490-492 ISSN 0587-4246. [International Symposium on Physics of Materials, ISPMA /12./. Praha, 04.09.2011-08.09.2011] R&D Projects: GA AV ČR IAA100100920 Institutional research plan: CEZ:AV0Z10100520 Keywords : ab-initio calculations * close-packed structures * generalized stacking faults * homogeneous deformation * lattice deformation * many-body potentials Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 0.531, year: 2012

  9. The SLUGGS survey: globular cluster stellar population trends from weak absorption lines in stacked spectra (United States)

    Usher, Christopher; Forbes, Duncan A.; Brodie, Jean P.; Romanowsky, Aaron J.; Strader, Jay; Conroy, Charlie; Foster, Caroline; Pastorello, Nicola; Pota, Vincenzo; Arnold, Jacob A.


    As part of the SAGES Legacy Unifying Globulars and GalaxieS (SLUGGS) survey, we stack 1137 Keck DEIMOS (Deep Imaging Multi-Object Spectrograph) spectra of globular clusters from 10 galaxies to study their stellar populations in detail. The stacked spectra have median signal-to-noise ratios of ˜90 Å-1. Besides the calcium triplet, we study weaker sodium, magnesium, titanium and iron lines as well as the Hα and higher order Paschen hydrogen lines. In general, the stacked spectra are consistent with old ages and a Milky Way-like initial mass function. However, we see different metal line index strengths at fixed colour and magnitude, and differences in the calcium triplet-colour relation from galaxy to galaxy. We interpret this as strong evidence for variations in the globular cluster colour-metallicity relation between galaxies. Two possible explanations for the colour-metallicity relation variations are that the average ages of globular clusters vary from galaxy to galaxy or that the average abundances of light elements (i.e. He, C, N and O) differ between galaxies. Stacking spectra by magnitude, we see that the colours become redder and metal line indices stronger with brighter magnitudes. These trends are consistent with the previously reported `blue tilts' being mass-metallicity relations.

  10. Sampled-time control of a microbial fuel cell stack (United States)

    Boghani, Hitesh C.; Dinsdale, Richard M.; Guwy, Alan J.; Premier, Giuliano C.


    Research into microbial fuel cells (MFCs) has reached the point where cubic metre-scale systems and stacks are being built and tested. Apart from performance enhancement through catalysis, materials and design, an important research area for industrial applicability is stack control, which can enhance MFCs stack power output. An MFC stack is controlled using a sampled-time digital control strategy, which has the advantage of intermittent operation with consequent power saving, and when used in a hybrid series stack connectivity, can avoid voltage reversals. A MFC stack comprising four tubular MFCs was operated hydraulically in series. Each MFC was connected to an independent controller and the stack was connected electrically in series, creating a hybrid-series connectivity. The voltage of each MFC in the stack was controlled such that the overall series stack voltage generated was the algebraic sum (1.26 V) of the individual MFC voltages (0.32, 0.32, 0.32 and 0.3). The controllers were able to control the individual voltages to the point where 2.52 mA was drawn from the stack at a load of 499.9 Ω (delivering 3.18 mW). The controllers were able to reject the disturbances and perturbations caused by electrical loading, temperature and substrate concentration.

  11. Modeling of column apparatus processes

    CERN Document Server

    Boyadjiev, Christo; Boyadjiev, Boyan; Popova-Krumova, Petya


    This book presents a new approach for the modeling of chemical and interphase mass transfer processes in industrial column apparatuses, using convection-diffusion and average-concentration models. The convection-diffusion type models are used for a qualitative analysis of the processes and to assess the main, small and slight physical effects, and then reject the slight effects. As a result, the process mechanism can be identified. It also introduces average concentration models for quantitative analysis, which use the average values of the velocity and concentration over the cross-sectional area of the column. The new models are used to analyze different processes (simple and complex chemical reactions, absorption, adsorption and catalytic reactions), and make it possible to model the processes of gas purification with sulfur dioxide, which form the basis of several patents.

  12. A new method for earthquake depth determination: stacking multiple-station autocorrelograms (United States)

    Zhang, Miao; Tian, Dongdong; Wen, Lianxing


    Accurate determination of earthquake depth is important, but particularly challenging. We develop a new method to determine the earthquake source depth by stacking multiple-station autocorrelograms (SMAC) of seismic data. The basic concept of SMAC method is to enhance the coherent surface reflected energy by autocorrelation and stacking, and uses the surface reflected energy to determine the source depth. Autocorrelation effectively enhances the energy of the seismic phases related to the source depth, while stacking the autocorrelograms of array data further improves the signal-to-noise ratio of the energy. The procedures are applied using both the main SH waves and the coda. Using coda waves, the method extracts the two-way traveltime between the source and the surface by stacking the coda wave autocorrelations over an array of seismic observations. Using the main SH waves, SMAC explores the interference of the down-going Moho reflected SmS wave and up-going surface bounced Moho reflected sSmS wave by autocorrelation. The autocorrelograms are then stacked along theoretical differential sSmS-SmS traveltime predicted for all potential source depths, and the source depth is determined to be the one that produces the maximum stacking energy. Synthetic tests demonstrate the validity of the SMAC procedures. As an example of application, we apply the SMAC method to determine the source depth of an earthquake occurring in Japan Island. The procedures of using both main SH waves and their coda waves yield robust surface reflected energy and a consistent source depth. The error of the depth estimation is less than 1 km assuming an uncertainty of 10 per cent in the averaged crust velocity.

  13. Analysis of stacking overlap in nucleic acid structures: algorithm and application. (United States)

    Pingali, Pavan Kumar; Halder, Sukanya; Mukherjee, Debasish; Basu, Sankar; Banerjee, Rahul; Choudhury, Devapriya; Bhattacharyya, Dhananjay


    RNA contains different secondary structural motifs like pseudo-helices, hairpin loops, internal loops, etc. in addition to anti-parallel double helices and random coils. The secondary structures are mainly stabilized by base-pairing and stacking interactions between the planar aromatic bases. The hydrogen bonding strength and geometries of base pairs are characterized by six intra-base pair parameters. Similarly, stacking can be represented by six local doublet parameters. These dinucleotide step parameters can describe the quality of stacking between Watson-Crick base pairs very effectively. However, it is quite difficult to understand the stacking pattern for dinucleotides consisting of non canonical base pairs from these parameters. Stacking interaction is a manifestation of the interaction between two aromatic bases or base pairs and thus can be estimated best by the overlap area between the planar aromatic moieties. We have calculated base pair overlap between two consecutive base pairs as the buried van der Waals surface between them. In general, overlap values show normal distribution for the Watson-Crick base pairs in most double helices within a range from 45 to 50 Å(2) irrespective of base sequence. The dinucleotide steps with non-canonical base pairs also are seen to have high overlap value, although their twist and few other parameters are rather unusual. We have analyzed hairpin loops of different length, bulges within double helical structures and pseudo-continuous helices using our algorithm. The overlap area analyses indicate good stacking between few looped out bases especially in GNRA tetraloop, which was difficult to quantitatively characterise from analysis of the base pair or dinucleotide step parameters. This parameter is also seen to be capable to distinguish pseudo-continuous helices from kinked helix junctions.

  14. Evaluation of uncertainty in experimental active buckling control of a slender beam-column with disturbance forces using Weibull analysis (United States)

    Enss, Georg C.; Platz, Roland


    Buckling of slender load-bearing beam-columns is a crucial failure scenario in light-weight structures as it may result in the collapse of the entire structure. If axial load and load capacity are unknown, stability becomes uncertain. To compensate this uncertainty, the authors successfully developed and evaluated an approach for active buckling control for a slender beam-column, clamped at the base and pinned at the upper end. Active lateral forces are applied with two piezoelectric stack actuators in opposing directions near the beam-column' clamped base to prevent buckling. A Linear Quadratic Regulator is designed and implemented on the experimental demonstrator and statistical tests are conducted to prove effectivity of the active approach. The load capacity of the beam-column could be increased by 40% and scatter of buckling occurrences for increasing axial loads is reduced. Weibull analysis is used to evaluate the increase of the load capacity and its related uncertainty compensation.

  15. AC impedance diagnosis of a 500 W PEM fuel cell stack . Part I: Stack impedance (United States)

    Yuan, Xiaozi; Sun, Jian Colin; Blanco, Mauricio; Wang, Haijiang; Zhang, Jiujun; Wilkinson, David P.

    Diagnosis of stack performance is of importance to proton exchange membrane (PEM) fuel cell research. This paper presents the diagnostic testing results of a 500 W Ballard Mark V PEM fuel cell stack with an active area of 280 cm 2 by electrochemical impedance spectroscopy (EIS). The EIS was measured using a combination of a FuelCon test station, a TDI loadbank, and a Solartron 1260 Impedance/Gain-Phase Analyzer operating in the galvanostatic mode. The method described in this work can obtain the impedance spectra of fuel cells with a larger geometric surface area and power, which are normally difficult to measure due to the limitations on commercial load banks operating at high currents. By using this method, the effects of temperature, flow rate, and humidity on the stack impedance spectra were examined. The results of the electrochemical impedance analysis show that with increasing temperature, the charge transfer resistance decreases due to the slow oxygen reduction reaction (ORR) process at low temperature. If the stack is operated at a fixed air flow rate, a low frequency arc appears and grows with increasing current due to the shortage of air. The anode humidification cut-off does not affect the spectra compared to the cut-off for cathode humidification.

  16. Stray field interaction of stacked amorphous tapes

    International Nuclear Information System (INIS)

    Guenther, Wulf; Flohrer, Sybille


    In this study, magnetic cores made of amorphous rectangular tape layers are investigated. The quality factor Q of the tape material decreases rapidly, however, when stacking at least two tape layers. The hysteresis loop becomes non-linear, and the coercivity increases. These effects are principally independent of the frequency and occur whether tape layers are insulated or not. The Kerr-microscopy was used to monitor local hysteresis loops by varying the distance of two tape layers. The magnetization direction of each magnetic domain is influenced by the anisotropy axis, the external magnetic field and the stray field of magnetic domains of the neighboring tape layers. We found that crossed easy axes (as the extreme case for inclined axes) of congruent domains retain the remagnetization and induce a plateau of the local loop. Summarizing local loops leads to the observed increase of coercivity and non-linearity of the inductively measured loop. A high Q-factor can be preserved if the easy axes of stacked tape layers are identical within the interaction range in the order of mm

  17. Annular feed air breathing fuel cell stack (United States)

    Wilson, Mahlon S.; Neutzler, Jay K.


    A stack of polymer electrolyte fuel cells is formed from a plurality of unit cells where each unit cell includes fuel cell components defining a periphery and distributed along a common axis, where the fuel cell components include a polymer electrolyte membrane, an anode and a cathode contacting opposite sides of the membrane, and fuel and oxygen flow fields contacting the anode and the cathode, respectively, wherein the components define an annular region therethrough along the axis. A fuel distribution manifold within the annular region is connected to deliver fuel to the fuel flow field in each of the unit cells. The fuel distribution manifold is formed from a hydrophilic-like material to redistribute water produced by fuel and oxygen reacting at the cathode. In a particular embodiment, a single bolt through the annular region clamps the unit cells together. In another embodiment, separator plates between individual unit cells have an extended radial dimension to function as cooling fins for maintaining the operating temperature of the fuel cell stack.

  18. Stacking Analysis of Binary Systems with HAWC (United States)

    Brisbois, Chad; HAWC Collaboration


    Detecting binary systems at TeV energies is an important problem because only a handful of such systems are currently known. The nature of such systems is typically thought to be composed of a compact object and a massive star. The TeV emission from these systems does not obviously correspond to emission in GeV or X-ray, where many binary systems have previously been found. This study focuses on a stacking method to detect TeV emission from LS 5039, a known TeV binary, to test its efficacy in HAWC data. Stacking is a widely employed method for increasing signal to noise ratio in optical astronomy, but has never been attempted previously with HAWC. HAWC is an ideal instrument to search for TeV binaries, because of its wide field of view and high uptime. Applying this method to the entire sky may allow HAWC to detect binary sources of very short or very long periods not sensitive to current analyses. NSF, DOE, Los Alamos, Michigan Tech, CONACyt, UNAM, BUAP.

  19. High performance zinc air fuel cell stack (United States)

    Pei, Pucheng; Ma, Ze; Wang, Keliang; Wang, Xizhong; Song, Mancun; Xu, Huachi


    A zinc air fuel cell (ZAFC) stack with inexpensive manganese dioxide (MnO2) as the catalyst is designed, in which the circulation flowing potassium hydroxide (KOH) electrolyte carries the reaction product away and acts as a coolant. Experiments are carried out to investigate the characteristics of polarization, constant current discharge and dynamic response, as well as the factors affecting the performance and uniformity of individual cells in the stack. The results reveal that the peak power density can be as high as 435 mW cm-2 according to the area of the air cathode sheet, and the influence factors on cell performance and uniformity are cell locations, filled state of zinc pellets, contact resistance, flow rates of electrolyte and air. It is also shown that the time needed for voltages to reach steady state and that for current step-up or current step-down are both in milliseconds, indicating the ZAFC can be excellently applied to vehicles with rapid dynamic response demands.

  20. Generalized stacking fault energies of alloys. (United States)

    Li, Wei; Lu, Song; Hu, Qing-Miao; Kwon, Se Kyun; Johansson, Börje; Vitos, Levente


    The generalized stacking fault energy (γ surface) provides fundamental physics for understanding the plastic deformation mechanisms. Using the ab initio exact muffin-tin orbitals method in combination with the coherent potential approximation, we calculate the γ surface for the disordered Cu-Al, Cu-Zn, Cu-Ga, Cu-Ni, Pd-Ag and Pd-Au alloys. Studying the effect of segregation of the solute to the stacking fault planes shows that only the local chemical composition affects the γ surface. The calculated alloying trends are discussed using the electronic band structure of the base and distorted alloys.Based on our γ surface results, we demonstrate that the previous revealed 'universal scaling law' between the intrinsic energy barriers (IEBs) is well obeyed in random solid solutions. This greatly simplifies the calculations of the twinning measure parameters or the critical twinning stress. Adopting two twinnability measure parameters derived from the IEBs, we find that in binary Cu alloys, Al, Zn and Ga increase the twinnability, while Ni decreases it. Aluminum and gallium yield similar effects on the twinnability.

  1. Computerized plutonium laboratory-stack monitoring system

    International Nuclear Information System (INIS)

    Stafford, R.G.; DeVore, R.K.


    The Los Alamos Scientific Laboratory has recently designed and constructed a Plutonium Research and Development Facility to meet design criteria imposed by the United States Energy Research and Development Administration. A primary objective of the design criteria is to assure environmental protection and to reliably monitor plutonium effluent via the ventilation exhaust systems. A state-of-the-art facility exhaust air monitoring system is described which establishes near ideal conditions for evaluating plutonium activity in the stack effluent. Total and static pressure sensing manifolds are incorporated to measure average velocity and integrated total discharge air volume. These data are logged at a computer which receives instrument data through a multiplex scanning system. A multipoint isokinetic sampling assembly with associated instrumentation is described. Continuous air monitors have been designed to sample from the isokinetic sampling assembly and transmit both instantaneous and integrated stack effluent concentration data to the computer and various cathode ray tube displays. The continuous air monitors also serve as room air monitors in the plutonium facility with the primary objective of timely evacuation of personnel if an above tolerance airborne plutonium concentration is detected. Several continuous air monitors are incorporated in the ventilation system to assist in identification of release problem areas

  2. Hollow-core FRP-concrete-steel bridge columns under extreme loading. (United States)


    This report presents the behavior of hollow-core fiber reinforced polymer concrete - steel columns (HC-FCS) under : combined axial-flexural as well as vehicle collision loads. The HC-FCS column consists of a concrete wall sandwiched between an ou...

  3. Engineering the bundled glass column: From the design concept to full-scale experimental testing

    NARCIS (Netherlands)

    Oikonomopoulou, F.; van den Broek, E.A.M.; Bristogianni, T.; Veer, F.A.; Nijsse, R.

    This article gives an overview of the research conducted by the authors from the design concept to the engineering and full-scale testing of the bundled glass column. Consisting of adhesively bonded solid glass rods, the bundled column is a promising solution for transparent compressive members. To

  4. Temperature programmable microfabricated gas chromatography column (United States)

    Manginell, Ronald P.; Frye-Mason, Gregory C.


    A temperature programmable microfabricated gas chromatography column enables more efficient chemical separation of chemical analytes in a gas mixture by the integration of a resistive heating element and temperature sensing on the microfabricated column. Additionally, means are provided to thermally isolate the heated column from their surroundings. The small heat capacity and thermal isolation of the microfabricated column improves the thermal time response and power consumption, both important factors for portable microanalytical systems.

  5. Description of gasket failure in a 7 cell PEMFC stack

    Energy Technology Data Exchange (ETDEWEB)

    Husar, Attila; Serra, Maria [Institut de Robotica i Informatica Industrial, Parc Tecnologic de Barcelona, Edifici U, C. Llorens i Artigas, 4-6, 2a Planta, 08028 Barcelona (Spain); Kunusch, Cristian [Laboratorio de Electronica Industrial Control e Instrumentacion, Facultad de Ingenieria, UNLP (Argentina)


    This article presents the data and the description of a fuel cell stack that failed due to gasket degradation. The fuel cell under study is a 7 cell stack. The unexpected change in several variables such as temperature, pressure and voltage indicated the possible failure of the stack. The stack was monitored over a 6 h period in which data was collected and consequently analyzed to conclude that the fuel cell stack failed due to a crossover leak on the anode inlet port located on the cathode side gasket of cell 2. This stack failure analysis revealed a series of indicators that could be used by a super visional controller in order to initiate a shutdown procedure. (author)

  6. Non-linear analysis of an experimental joint of column and beams of armed concrete-steel column for frame


    López, Nelson; Ugel, Ronald; Herrera, Reyes


    In this research, the nonlinear behavior of a real-scale experimental joint (node) is studied, consisting of three reinforced concrete elements, one column and two beams joined to a structural steel column at the upper level. In the numerical analysis the model of the union was analyzed in the inelastic range, this model was elaborated with the finite element program based on fibers, SeismoStruct to analyze as a function of time, the traction and compression efforts in the confined area and n...

  7. 29 CFR 1926.755 - Column anchorage. (United States)


    ... 29 Labor 8 2010-07-01 2010-07-01 false Column anchorage. 1926.755 Section 1926.755 Labor... (CONTINUED) SAFETY AND HEALTH REGULATIONS FOR CONSTRUCTION Steel Erection § 1926.755 Column anchorage. (a) General requirements for erection stability. (1) All columns shall be anchored by a minimum of 4 anchor...

  8. Education and training column: the learning collaborative. (United States)

    MacDonald-Wilson, Kim L; Nemec, Patricia B


    This column describes the key components of a learning collaborative, with examples from the experience of 1 organization. A learning collaborative is a method for management, learning, and improvement of products or processes, and is a useful approach to implementation of a new service design or approach. This description draws from published material on learning collaboratives and the authors' experiences. The learning collaborative approach offers an effective method to improve service provider skills, provide support, and structure environments to result in lasting change for people using behavioral health services. This approach is consistent with psychiatric rehabilitation principles and practices, and serves to increase the overall capacity of the mental health system by structuring a process for discovering and sharing knowledge and expertise across provider agencies. (PsycINFO Database Record (c) 2015 APA, all rights reserved).

  9. Quadratic forms and Clifford algebras on derived stacks


    Vezzosi, Gabriele


    In this paper we present an approach to quadratic structures in derived algebraic geometry. We define derived n-shifted quadratic complexes, over derived affine stacks and over general derived stacks, and give several examples of those. We define the associated notion of derived Clifford algebra, in all these contexts, and compare it with its classical version, when they both apply. Finally, we prove three main existence results for derived shifted quadratic forms over derived stacks, define ...

  10. Stacked Heterogeneous Neural Networks for Time Series Forecasting

    Directory of Open Access Journals (Sweden)

    Florin Leon


    Full Text Available A hybrid model for time series forecasting is proposed. It is a stacked neural network, containing one normal multilayer perceptron with bipolar sigmoid activation functions, and the other with an exponential activation function in the output layer. As shown by the case studies, the proposed stacked hybrid neural model performs well on a variety of benchmark time series. The combination of weights of the two stack components that leads to optimal performance is also studied.

  11. A novel configuration for direct internal reforming stacks (United States)

    Fellows, Richard

    This paper presents a stack concept that can be applied to both molten carbonate fuel cell (MCFC) and solid oxide fuel cell (SOFC) internal reforming stacks. It employs anode recycle and allows the design of very simple system configurations, while giving enhanced efficiencies and high specific power densities. The recycle of anode exit gas to the anode inlet has previously been proposed as a means of preventing carbon deposition in direct internal reforming (DIR) stacks. When applied to a normal stack this reduces the Nernst voltages because the recycle stream is relatively depleted in hydrogen. In the concept proposed here, known as the `Smarter' stack, there are two anode exit streams, one of which is depleted, while the other is relatively undepleted. The depleted stream passes directly to the burner, and the undepleted stream is recycled to the stack inlet. By this means high Nernst voltages are achieved in the stack. The concept has been simulated and assessed for parallel-flow and cross-flow MCFC and SOFC stacks and graphs are presented showing temperature distributions. The `Smarter' stacks employ a high recycle rate resulting in a reduced natural gas concentration at the stack inlet, and this reduces or eliminates the unfavourable temperature dip. Catalyst grading can further improve the temperature distribution. The concept allows simple system configurations in which the need for fuel pre-heat is eliminated. Efficiencies are up to 10 percentage points higher than for conventional stacks with the same cell area and maximum stack temperature. The concept presented here was devised in a project part-funded by the EU, and has been adopted by the European Advanced DIR-MCFC development programme led by BCN.

  12. Status of Slip Stacking at Fermilab Main Injector

    CERN Document Server

    Seiya, Kiyomi; Chase, Brian; Dey, Joseph; Kourbanis, Ioanis; MacLachlan, James A; Meisner, Keith G; Pasquinelli, Ralph J; Reid, John; Rivetta, Claudio H; Steimel, Jim


    In order to increase proton intensity on anti proton production cycle of the Main Injector we are going to use the technique of 'slip stacking' and doing machine studies. In slip stacking, one bunch train is injected at slightly lower energy and second train is at slightly higher energy. Afterwards they are aligned longitudinally and captured with one rf bucket. This longitudinal stacking process is expected to double the bunch intensity. The required intensity for anti proton production is 8·1012

  13. A novel design for solid oxide fuel cell stacks

    Energy Technology Data Exchange (ETDEWEB)

    Al-Qattan, A.M.; Chmielewski, D.J.; Al-Hallaj, S.; Selman, J.R. [Illinois Inst. of Technology, Chicago, IL (United States). Dept. of Chemical and Environmental Engineering


    Conventional fuel cell stack designs suffer from severe spatial nonuniformity in both temperature and current density. Such variations are known to create damaging thermal stresses within the stack and thus, impact overall lifespan. In this work, we propose a novel stack design aimed at reducing spatial variations at the source. We propose a mechanism of distributed fuel feed in which the heat generation profile can be influenced directly. Simulation results are presented to illustrate the potential of the proposed scheme. (author)

  14. Development of the electric utility dispersed use PAFC stack

    Energy Technology Data Exchange (ETDEWEB)

    Horiuchi, Hiroshi; Kotani, Ikuo [Mitsubishi Electric Co., Kobe (Japan); Morotomi, Isamu [Kansai Electric Power Co., Hyogo (Japan)] [and others


    Kansai Electric Power Co. and Mitsubishi Electric Co. have been developing the electric utility dispersed use PAFC stack operated under the ambient pressure. The new cell design have been developed, so that the large scale cell (1 m{sup 2} size) was adopted for the stack. To confirm the performance and the stability of the 1 m{sup 2} scale cell design, the short stack study had been performed.

  15. Integrity of Bolted Angle Connections Subjected to Simulated Column Removal (United States)

    Weigand, Jonathan M.; Berman, Jeffrey W.


    Large-scale tests of steel gravity framing systems (SGFSs) have shown that the connections are critical to the system integrity, when a column suffers damage that compromises its ability to carry gravity loads. When supporting columns were removed, the SGFSs redistributed gravity loads through the development of an alternate load path in a sustained tensile configuration resulting from large vertical deflections. The ability of the system to sustain such an alternate load path depends on the capacity of the gravity connections to remain intact after undergoing large rotation and axial extension demands, for which they were not designed. This study experimentally evaluates the performance of steel bolted angle connections subjected to loading consistent with an interior column removal. The characteristic connection behaviors are described and the performance of multiple connection configurations are compared in terms of their peak resistances and deformation capacities. PMID:27110059

  16. Method for monitoring stack gases for uranium activity

    International Nuclear Information System (INIS)

    Beverly, C.R.; Ernstberger, H.G.


    A method for sampling stack gases emanating from the purge cascade of a gaseous diffusion cascade system utilized to enrich uranium for determining the presence and extent of uranium in the stack gases in the form of gaseous uranium hexafluoride, is described comprising the steps of removing a side stream of gases from the stack gases, contacting the side stream of the stack gases with a stream of air sufficiently saturated with moisture for reacting with and converting any gaseous uranium hexafluroide contracted thereby in the side stream of stack gases to particulate uranyl fluoride. Thereafter contacting the side stream of stack gases containing the particulate uranyl fluoride with moving filter means for continuously intercepting and conveying the intercepted particulate uranyl fluoride away from the side stream of stack gases, and continually scanning the moving filter means with radiation monitoring means for sensing the presence and extent of particulate uranyl fluoride on the moving filter means which is indicative of the extent of particulate uranyl fluoride in the side stream of stack gases which in turn is indicative of the presence and extent of uranium hexafluoride in the stack gases

  17. Design and development of an automated uranium pellet stacking system

    International Nuclear Information System (INIS)

    Reiss, B.S.; Nokleby, S.B.


    A novel design for an automated uranium pellet stacking system is presented. This system is designed as a drop-in solution to the current production line to enhance the fuel pellet stacking process. The three main goals of this system are to reduce worker exposure to radiation to as low as reasonable achievable (ALARA), improve product quality, and increase productivity. The proposed system will reduce the potential for human error. This single automated system will replace the two existing pellet stacking stations while increasing the total output, eliminating pellet stacking as a bottleneck in the fuel bundle assembly process. (author)

  18. Highly Efficient, Durable Regenerative Solid Oxide Stack, Phase I (United States)

    National Aeronautics and Space Administration — Precision Combustion, Inc. (PCI) proposes to develop a highly efficient regenerative solid oxide stack design. Novel structural elements allow direct internal...

  19. CFD and CHD in random packing columns with seawater desulfurization

    Energy Technology Data Exchange (ETDEWEB)

    Gao, Mei-Shan [Southeast Univ., Nanjing (China). College of Civil Engineering; Wang, Shi-He; Wang, Xiao-Ming [State Power Environmental Protection Research Institute, Nanjing (China); Guo, Ming-Chun [Shanghai Huolin engineering Plastics Co., Ltd., Shanghai (China)


    By the volume average method, gas-liquid two-phase flow CFD and CHT model is established to describe the random packing column in seawater desulfurization. By numerical calculation, the flow velocity, porosity distribution, pressure distribution and temperature distribution of seawater are obtained. Pressure loss and the outlet temperature of seawater are compared with experimental data, the prediction results and experimental results are well consistent, is exactly the same trend. Analyzing the results of calculation, a significant ''wall flow'' phenomena was found, and the reason of its formation is that the porosity of filler near the wall is significantly higher than in the middle region. Analyzing the distribution of seawater temperature, it is found that the distribution of seawater temperature is more uniform on the top of column, the seawater temperature near the wall fluctuated and were gradually more uniform towards the center of the column. Along the direction of the column from top to bottom, the seawater temperature gradually decreased, and the degree of fluctuations gradually reduced and basically does not change at half of the column, which indicated that the heat exchange between the gas and liquid has been basically completed.

  20. Long-term operation of a solid oxide cell stack for coelectrolysis of steam and CO2

    DEFF Research Database (Denmark)

    Agersted, Karsten; Chen, Ming; Blennow, Peter


    High temperature electrolysis based on solid oxide electrolysis cells (SOECs) is a promising technology for production of synthetic fuels. The SOEC units can be used for co-electrolysis of steam and CO2 to produce synthesis gas (syngas, CO+H2), which can be further processed to a variety...... consists of Ni/YSZ electrode supported SOEC cells with a footprint of 12X12 cm2. The co-electrolysis operation was carried out by supplying a mixture of 45 % CO2 + 45 % H2O + 10 % H2 to the stack operating with a fixed conversion of 39 % for steam and CO2. The stack was operated at different conditions...... of synthetic fuels such as methane, methanol or DME. Previously we have reported electrolysis operation of solid oxide cell stacks for periods up to about 1000 hours. In this work, operation of a Haldor Topsoe 8-cell stack (stack design of 2014) in co-electrolysis mode for 6000 hours is reported. The stack...

  1. Axisymmetric collapses of granular columns (United States)

    Lube, Gert; Huppert, Herbert E.; Sparks, R. Stephen J.; Hallworth, Mark A.


    Experimental observations of the collapse of initially vertical columns of small grains are presented. The experiments were performed mainly with dry grains of salt or sand, with some additional experiments using couscous, sugar or rice. Some of the experimental flows were analysed using high-speed video. There are three different flow regimes, dependent on the value of the aspect ratio a {=} h_i/r_i, where h_i and r_i are the initial height and radius of the granular column respectively. The differing forms of flow behaviour are described for each regime. In all cases a central, conically sided region of angle approximately 59(°) , corresponding to an aspect ratio of 1.7, remains undisturbed throughout the motion. The main experimental results for the final extent of the deposit and the time for emplacement are systematically collapsed in a quantitative way independent of any friction coefficients. Along with the kinematic data for the rate of spread of the front of the collapsing column, this is interpreted as indicating that frictional effects between individual grains in the bulk of the moving flow only play a role in the last instant of the flow, as it comes to an abrupt halt. For a {reach r_infty is given by t_infty {=} 3(h_i/g)(1/2} {=} 3(r_i/g)({1/2}a^{1/2)) , where g is the gravitational acceleration. The insights and conclusions gained from these experiments can be applied to a wide range of industrial and natural flows of concentrated particles. For example, the observation of the rapid deposition of the grains can help explain details of the emplacement of pyroclastic flows resulting from the explosive eruption of volcanoes.

  2. Manifold seal structure for fuel cell stack (United States)

    Collins, William P.


    The seal between the sides of a fuel cell stack and the gas manifolds is improved by adding a mechanical interlock between the adhesive sealing strip and the abutting surface of the manifolds. The adhesive is a material which can flow to some extent when under compression, and the mechanical interlock is formed providing small openings in the portion of the manifold which abuts the adhesive strip. When the manifolds are pressed against the adhesive strips, the latter will flow into and through the manifold openings to form buttons or ribs which mechanically interlock with the manifolds. These buttons or ribs increase the bond between the manifolds and adhesive, which previously relied solely on the adhesive nature of the adhesive.

  3. Directive Stacked Patch Antenna for UWB Applications

    Directory of Open Access Journals (Sweden)

    Sharif I. Mitu Sheikh


    Full Text Available Directional ultrawideband (UWB antennas are popular in wireless signal-tracking and body-area networks. This paper presents a stacked microstrip antenna with an ultrawide impedance bandwidth of 114%, implemented by introducing defects on the radiating patches and the ground plane. The compact (20×34 mm antenna exhibits a directive radiation patterns for all frequencies of the 3–10.6 GHz band. The optimized reflection response and the radiation pattern are experimentally verified. The designed UWB antenna is used to maximize the received power of a software-defined radio (SDR platform. For an ultrawideband impulse radio system, this class of antennas is essential to improve the performance of the communication channels.

  4. ATLAS software stack on ARM64 (United States)

    Smith, Joshua Wyatt; Stewart, Graeme A.; Seuster, Rolf; Quadt, Arnulf; ATLAS Collaboration


    This paper reports on the port of the ATLAS software stack onto new prototype ARM64 servers. This included building the “external” packages that the ATLAS software relies on. Patches were needed to introduce this new architecture into the build as well as patches that correct for platform specific code that caused failures on non-x86 architectures. These patches were applied such that porting to further platforms will need no or only very little adjustments. A few additional modifications were needed to account for the different operating system, Ubuntu instead of Scientific Linux 6 / CentOS7. Selected results from the validation of the physics outputs on these ARM 64-bit servers will be shown. CPU, memory and IO intensive benchmarks using ATLAS specific environment and infrastructure have been performed, with a particular emphasis on the performance vs. energy consumption.

  5. ATLAS software stack on ARM64

    CERN Document Server

    AUTHOR|(INSPIRE)INSPIRE-00529764; The ATLAS collaboration; Stewart, Graeme; Seuster, Rolf; Quadt, Arnulf


    This paper reports on the port of the ATLAS software stack onto new prototype ARM64 servers. This included building the “external” packages that the ATLAS software relies on. Patches were needed to introduce this new architecture into the build as well as patches that correct for platform specific code that caused failures on non-x86 architectures. These patches were applied such that porting to further platforms will need no or only very little adjustments. A few additional modifications were needed to account for the different operating system, Ubuntu instead of Scientific Linux 6 / CentOS7. Selected results from the validation of the physics outputs on these ARM 64-bit servers will be shown. CPU, memory and IO intensive benchmarks using ATLAS specific environment and infrastructure have been performed, with a particular emphasis on the performance vs. energy consumption.

  6. Stacked generalization: an introduction to super learning. (United States)

    Naimi, Ashley I; Balzer, Laura B


    Stacked generalization is an ensemble method that allows researchers to combine several different prediction algorithms into one. Since its introduction in the early 1990s, the method has evolved several times into a host of methods among which is the "Super Learner". Super Learner uses V-fold cross-validation to build the optimal weighted combination of predictions from a library of candidate algorithms. Optimality is defined by a user-specified objective function, such as minimizing mean squared error or maximizing the area under the receiver operating characteristic curve. Although relatively simple in nature, use of Super Learner by epidemiologists has been hampered by limitations in understanding conceptual and technical details. We work step-by-step through two examples to illustrate concepts and address common concerns.

  7. Actuators Using Piezoelectric Stacks and Displacement Enhancers (United States)

    Bar-Cohen, Yoseph; Sherrit, Stewart; Bao, Xiaoqi; Badescu, Mircea; Lee, Hyeong Jae; Walkenmeyer, Phillip; Lih, Shyh-Shiuh


    Actuators are used to drive all active mechanisms including machines, robots, and manipulators to name a few. The actuators are responsible for moving, manipulating, displacing, pushing and executing any action that is needed by the mechanism. There are many types and principles of actuation that are responsible for these movements ranging from electromagnetic, electroactive, thermo-mechanic, piezoelectric, electrostrictive etc. Actuators are readily available from commercial producers but there is a great need for reducing their size, increasing their efficiency and reducing their weight. Studies at JPL’s Non Destructive Evaluation and Advanced Actuators (NDEAA) Laboratory have been focused on the use of piezoelectric stacks and novel designs taking advantage of piezoelectric’s potential to provide high torque/force density actuation and high electromechanical conversion efficiency. The actuators/motors that have been developed and reviewed in this paper are operated by various horn configurations as well as the use of pre-stress flexures that make them thermally stable and increases their coupling efficiency. The use of monolithic designs that pre-stress the piezoelectric stack eliminates the use of compression stress bolt. These designs enable the embedding of developed solid-state motors/actuators in any structure with the only macroscopically moving parts are the rotor or the linear translator. Finite element modeling and design tools were used to determine the requirements and operation parameters and the results were used to simulate, design and fabricate novel actuators/motors. The developed actuators and performance will be described and discussed in this paper.

  8. Combining parametric, semi-parametric, and non-parametric survival models with stacked survival models. (United States)

    Wey, Andrew; Connett, John; Rudser, Kyle


    For estimating conditional survival functions, non-parametric estimators can be preferred to parametric and semi-parametric estimators due to relaxed assumptions that enable robust estimation. Yet, even when misspecified, parametric and semi-parametric estimators can possess better operating characteristics in small sample sizes due to smaller variance than non-parametric estimators. Fundamentally, this is a bias-variance trade-off situation in that the sample size is not large enough to take advantage of the low bias of non-parametric estimation. Stacked survival models estimate an optimally weighted combination of models that can span parametric, semi-parametric, and non-parametric models by minimizing prediction error. An extensive simulation study demonstrates that stacked survival models consistently perform well across a wide range of scenarios by adaptively balancing the strengths and weaknesses of individual candidate survival models. In addition, stacked survival models perform as well as or better than the model selected through cross-validation. Finally, stacked survival models are applied to a well-known German breast cancer study. © The Author 2015. Published by Oxford University Press. All rights reserved. For permissions, please e-mail:

  9. Parsing of the free energy of aromatic-aromatic stacking interactions in solution

    Energy Technology Data Exchange (ETDEWEB)

    Kostjukov, Viktor V.; Khomytova, Nina M. [Department of Physics, Sevastopol National Technical University, Sevastopol 99053, Crimea (Ukraine); Hernandez Santiago, Adrian A.; Tavera, Anna-Maria Cervantes; Alvarado, Julieta Salas [Faculty of Chemical Sciences, Autonomous University of Puebla, Puebla (Mexico); Evstigneev, Maxim P., E-mail: [Department of Physics, Sevastopol National Technical University, Sevastopol 99053, Crimea (Ukraine)


    Graphical abstract: Highlights: > A protocol for decomposition of the free energy of aromatic stacking is developed. > The factors stabilizing/destabilizing stacking of aromatic molecules are defined. > Hydrophobic contribution is found to be dominant. - Abstract: We report an analysis of the energetics of aromatic-aromatic stacking interactions for 39 non-covalent reactions of self- and hetero-association of 12 aromatic molecules with different structures and charge states. A protocol for computation of the contributions to the total energy from various energetic terms has been developed and the results are consistent with experiment in 92% of all the systems studied. It is found that the contributions from hydrogen bonds and entropic factors are always unfavorable, whereas contributions from van-der-Waals, electrostatic and/or hydrophobic effects may lead to stabilizing or destabilizing factors depending on the system studied. The analysis carried out in this work provides an answer to the questions 'What forces stabilize/destabilize the stacking of aromatic molecules in aqueous-salt solution and what are their relative importance?'

  10. Parsing of the free energy of aromatic-aromatic stacking interactions in solution

    International Nuclear Information System (INIS)

    Kostjukov, Viktor V.; Khomytova, Nina M.; Hernandez Santiago, Adrian A.; Tavera, Anna-Maria Cervantes; Alvarado, Julieta Salas; Evstigneev, Maxim P.


    Graphical abstract: Highlights: → A protocol for decomposition of the free energy of aromatic stacking is developed. → The factors stabilizing/destabilizing stacking of aromatic molecules are defined. → Hydrophobic contribution is found to be dominant. - Abstract: We report an analysis of the energetics of aromatic-aromatic stacking interactions for 39 non-covalent reactions of self- and hetero-association of 12 aromatic molecules with different structures and charge states. A protocol for computation of the contributions to the total energy from various energetic terms has been developed and the results are consistent with experiment in 92% of all the systems studied. It is found that the contributions from hydrogen bonds and entropic factors are always unfavorable, whereas contributions from van-der-Waals, electrostatic and/or hydrophobic effects may lead to stabilizing or destabilizing factors depending on the system studied. The analysis carried out in this work provides an answer to the questions 'What forces stabilize/destabilize the stacking of aromatic molecules in aqueous-salt solution and what are their relative importance?'

  11. A Development of 2 kW Molten Carbonate Fuel Cell Stack

    Energy Technology Data Exchange (ETDEWEB)

    Lim, Hee Chun [Korea Electric Power Research Institute, Taejon (Korea, Republic of); Jung, Jong Soo [SAMSUNG HEAVY INDUSTRY (Korea, Republic of); Hong, Sung Ahn [Korea Institute of science and Technology, Seoul (Korea, Republic of)


    The molten carbonate fuel cell (MCFC) has been under intensive development during the last decade as the second generation fuel cell, since it has high efficiency at its operating temperature of 650 deg. C and coal gas can be utilized as the fuel. A 2 kW MCFC stack, consisted of 20 cells, was fabricated with 1,000 cm{sup 2}-area electrode and showed 16 volt at 150 A, producing stable power more than 2.4 kW. The test facility was constructed for the evaluation of the stack. The followings are included in this study : 1. Establishment of the scale-up technology of MCFC components. 2. Settling of the unit cell technology and its long term operation. 3. Manufacturing of a small scale stack and establishment of the stack operation. The feasibility study was carried out for the 100 kW class MCFC pilot plant system through the concept design. (author). 12 refs., figs. tabs.

  12. An industrial FT-IR process gas analyzer for stack gas cems analysis

    Energy Technology Data Exchange (ETDEWEB)

    Welch, G.M. [American instruments, Anacortes, WA (United States); Herman, B.E. [Applied Automation/Hartmann & Braun, Bartlesville, OK (United States)


    This paper describes utilizing Fourier Transform Infrared (FT-IR) technology to meet and exceed EPA requirements to Continuously Monitor Carbon Monoxide (CO) and Sulfur Dioxide (SO){sub 2} in an oil refinery. The application consists of Continuous Emission Monitoring (CEMS) of two stacks from a Fluid Catalytic Cracking unit (FCCU). The discussion will follow the project from initial specifications, installation, start-up, certification results (RATA, 7 day drift), Cylinder Gas Audit (CGA) and the required maintenance. FT-IR is a powerful analytical tool suitable for measurement of stack component gases required to meet CEMS regulations, and allows simultaneous multi-component analysis of complex stack gas streams with a continuous sample stream flow through the measurement cell. The Michelson Interferometer in a unique {open_quotes}Wishbone{close_quotes} design and with a special alignment control enables standardized configuration of the analyzer for flue gas analysis. Normal stack gas pollutants: NO{sub x}, SO{sub 2}, and CO; as well as water soluble pollutants such as NH{sub 3} and HCI may be accurately determined and reported even in the presence of 0-31 Vol % water vapor concentrations (hot and wet). This FT-IR analyzer has been operating with EPA Certification in an oil refinery environment since September 1994.

  13. Evaluation of field emission properties from multiple-stacked Si quantum dots

    International Nuclear Information System (INIS)

    Takeuchi, Daichi; Makihara, Katsunori; Ohta, Akio; Ikeda, Mitsuhisa; Miyazaki, Seiichi


    Multiple-stacked Si quantum dots (QDs) with ultrathin SiO 2 interlayers were formed on ultrathin SiO 2 layers by repeating a process sequence consisting of the formation of Si-QDs by low pressure chemical vapor deposition using a SiH 4 gas and the surface oxidation and subsequent surface modification by remote hydrogen and oxygen plasmas, respectively. To clarify the electron emission mechanism from multiple-stacked Si-QDs covered with an ultrathin Au top electrode, the energy distribution of the emitted electrons and its electric field dependence was measured using a hemispherical electron energy analyzer in an X-ray photoelectron spectroscopy system under DC bias application to the multiple-stacked Si-QD structure. At − 6 V and over, the energy distributions reached a peak at ~ 2.5 eV with a tail toward the higher energy side. While the electron emission intensity was increased exponentially with an increase in the applied DC bias, there was no significant increase in the emission peak energy. The observed emission characteristics can be interpreted in terms of field emissions from the second and/or third topmost Si-QDs resulting from the electric concentration there. - Highlights: • Electron field emission from 6-fold stack of Si-QDs has been evaluated. • AFM measurements show the local electron emission from individual Si-QDs. • Impact of applied bias on the electron emission energy distribution was investigated.

  14. Series Assembly of Microbial Desalination Cells Containing Stacked Electrodialysis Cells for Partial or Complete Seawater Desalination

    KAUST Repository

    Kim, Younggy


    A microbial desalination cell (MDC) is a new approach for desalinating water based on using the electrical current generated by exoelectrogenic bacteria. Previously developed MDCs have used only one or two desalination chambers with substantial internal resistance, and used low salinity catholytes containing a buffered or acid solution. Here we show that substantially improved MDC performance can be obtained even with a nonbuffered, saline catholyte, by using an electrodialysis stack consisting of 5 pairs of desalting and concentrating cells. When 4 stacked MDCs were used in series (20 total pairs of desalination chambers), the salinity of 0.06 L of synthetic seawater (35 g/L NaCl) was reduced by 44% using 0.12 L of anode solution (2:1). The resistive loss in the electrodialysis stack was negligible due to minimization of the intermembrane distances, and therefore the power densities produced by the MDC were similar to those produced by single chamber microbial fuel cells (MFCs) lacking desalination chambers. The observed current efficiency was 86%, indicating separation of 4.3 pairs of sodium and chloride ions for every electron transferred through the circuit. With two additional stages (total of 3.8 L of anolyte), desalination was increased to 98% salt removal, producing 0.3 L of fresh water (12.6:1). These results demonstrate that stacked MDCs can be used for efficient desalination of seawater while at the same time achieving power densities comparable to those obtained in MFCs. © 2011 American Chemical Society.

  15. Development and Characterization of an Electrically Rechargeable Zinc-Air Battery Stack

    Directory of Open Access Journals (Sweden)

    Hongyun Ma


    Full Text Available An electrically rechargeable zinc-air battery stack consisting of three single cells in series was designed using a novel structured bipolar plate with air-breathing holes. Alpha-MnO2 and LaNiO3 severed as the catalysts for the oxygen reduction reaction (ORR and oxygen evolution reaction (OER. The anodic and cathodic polarization and individual cell voltages were measured at constant charge-discharge (C-D current densities indicating a uniform voltage profile for each single cell. One hundred C-D cycles were carried out for the stack. The results showed that, over the initial 10 cycles, the average C-D voltage gap was about 0.94 V and the average energy efficiency reached 89.28% with current density charging at 15 mA·cm−2 and discharging at 25 mA·cm−2. The total increase in charging voltage over the 100 C-D cycles was ~1.56% demonstrating excellent stability performance. The stack performance degradation was analyzed by galvanostatic electrochemical impedance spectroscopy. The charge transfer resistance of ORR increased from 1.57 to 2.21 Ω and that of Zn/Zn2+ reaction increased from 0.21 to 0.34 Ω after 100 C-D cycles. The quantitative analysis guided the potential for the optimization of both positive and negative electrodes to improve the cycle life of the cell stack.

  16. Density functional MO calculation for stacked DNA base-pairs with backbones. (United States)

    Kurita, N; Kobayashi, K


    In order to elucidate the effect of the sugar and phosphate backbones on the stable structure and electronic properties of stacked DNA base-pairs, we performed ab initio molecular orbital (MO) calculations based on the density functional theory and Slater-type basis set. As a model cluster for stacked base-pairs, we employed three isomers for the dimer unit of stacked guanine-cytosine pairs composed with backbones as well as base-pairs. These structures were fully optimized and their electronic properties were self-consistently investigated. By including the backbones, the difference in total energy among the isomers was largely enhanced, while the trend in relative stability was not changed. The effect of backbones on the electronic properties is remarkable: the MOs with the character of the PO4 parts of backbones appear just below the highest-occupied MO. This result indicates that the PO4 parts might play a rule as a reaction site in chemical processes concerning DNA. Therefore, we conclude that the DNA backbones are indispensable for investigating the stability and electronic properties of the stacked DNA base-pairs.

  17. Series assembly of microbial desalination cells containing stacked electrodialysis cells for partial or complete seawater desalination. (United States)

    Kim, Younggy; Logan, Bruce E


    A microbial desalination cell (MDC) is a new approach for desalinating water based on using the electrical current generated by exoelectrogenic bacteria. Previously developed MDCs have used only one or two desalination chambers with substantial internal resistance, and used low salinity catholytes containing a buffered or acid solution. Here we show that substantially improved MDC performance can be obtained even with a nonbuffered, saline catholyte, by using an electrodialysis stack consisting of 5 pairs of desalting and concentrating cells. When 4 stacked MDCs were used in series (20 total pairs of desalination chambers), the salinity of 0.06 L of synthetic seawater (35 g/L NaCl) was reduced by 44% using 0.12 L of anode solution (2:1). The resistive loss in the electrodialysis stack was negligible due to minimization of the intermembrane distances, and therefore the power densities produced by the MDC were similar to those produced by single chamber microbial fuel cells (MFCs) lacking desalination chambers. The observed current efficiency was 86%, indicating separation of 4.3 pairs of sodium and chloride ions for every electron transferred through the circuit. With two additional stages (total of 3.8 L of anolyte), desalination was increased to 98% salt removal, producing 0.3 L of fresh water (12.6:1). These results demonstrate that stacked MDCs can be used for efficient desalination of seawater while at the same time achieving power densities comparable to those obtained in MFCs.

  18. Influence of the stacking sequence of layers on the mechanical behavior of polymeric composite cylinders

    International Nuclear Information System (INIS)

    Carvalho, Osni de


    This work evaluated experimentally the influence of the stacking sequence of layers symmetrical and asymmetrical on the mechanical behavior of polymeric composite cylinders. For so much, two open-ended cylinders groups were manufactured by filament winding process, which had different stacking sequence related to the laminate midplane, characterizing symmetrical and asymmetrical laminates. The composite cylinders were made with epoxy matrix and carbon fiber as reinforcement. For evaluation of the mechanical strength, the cylinders were tested hydrostatically, which consisted of internal pressurization in a hydrostatic device through the utilization of a fluid until the cylinders burst. Additionally, were compared the strains and failure modes between the cylinders groups. The utilization of a finite element program allowed to conclude that this tool, very used in design, does not get to identify tensions in the fiber direction in each composite layer, as well as interlaminar shear stress, that appears in the cylinders with asymmetrical stacking sequence. The tests results showed that the stacking sequence had influence in the mechanical behavior of the composite cylinders, favoring the symmetrical construction. (author)

  19. Linear identification and model adjustment of a PEM fuel cell stack

    Energy Technology Data Exchange (ETDEWEB)

    Kunusch, C.; Puleston, P.F.; More, J.J. [LEICI, Departamento de Electrotecnia, Universidad Nacional de La Plata, calle 1 esq. 47 s/n, 1900 La Plata (Argentina); Consejo de Investigaciones Cientificas y Tecnicas (CONICET) (Argentina); Husar, A. [Institut de Robotica i Informatica Industrial (CSIC-UPC), c/ Llorens i Artigas 4-6, 08028 Barcelona (Spain); Mayosky, M.A. [LEICI, Departamento de Electrotecnia, Universidad Nacional de La Plata, calle 1 esq. 47 s/n, 1900 La Plata (Argentina); Comision de Investigaciones Cientificas (CIC), Provincia de Buenos Aires (Argentina)


    In the context of fuel cell stack control a mayor challenge is modeling the interdependence of various complex subsystem dynamics. In many cases, the states interaction is usually modeled through several look-up tables, decision blocks and piecewise continuous functions. Many internal variables are inaccessible for measurement and cannot be used in control algorithms. To make significant contributions in this area, it is necessary to develop reliable models for control and design purposes. In this paper, a linear model based on experimental identification of a 7-cell stack was developed. The procedure followed to obtain a linear model of the system consisted in performing spectroscopy tests of four different single-input single-output subsystems. The considered inputs for the tests were the stack current and the cathode oxygen flow rate, while the measured outputs were the stack voltage and the cathode total pressure. The resulting model can be used either for model-based control design or for on-line analysis and errors detection. (author)

  20. Study of hydrodynamic and mass transfer parameters in pulsed sieve-plate columns

    International Nuclear Information System (INIS)

    Safdari, J.


    One of the most important liquid-liquid extractor in industry is pulsed column. The pulsed columns are generally classified into the following categories: 1-Pulsed perforated-plate column. 2- Pulsed packed column. The pulsed plate column is differential contactor with the application of mechanical energy and is used for a diverse range of processes. Probably its best known application has been in the nuclear fuel industry. The pulsed plate column consists of a cylindrical shell with settling zones at the top and the bottom of the column. The liquids are fed continuously to the column (flowing counter-currently) and are removed continuously from opposite ends of the column. In this work using a pilot pulsed plate column and two different chemical systems (toluene/acetone/water and n-butyl acetate/acetone/water) various experiments are carried out. In each experiment direction of mass transfer is from organic phase (dispersed phase) into aqueous phase (continuous phase) and the continuous phase is water. The main objects of this thesis are as follow: a- Investigation of effect of operating parameters on dispersed phase hold up, volumetric overall mass transfer coefficients based on dispersed and continuous phase, extraction efficiency, pressure drop of column and flooding velocities (maximum column capacities). Obtained results in this part show that if the calorimetric flow rate of aqueous phase or pulsation intensity increase, hold up, volumetric overall mass transfer coefficients based on both two phases and extraction efficiency will increase and flooding velocities will decrease. Also results show that if volumetric flow rate of organic phase increase, hold up, volumetric mass transfer coefficients based on both two phases and pressure drop will increase and extraction efficiency and flooding velocities will decrease. b- Investigation of effect of internal circulation inside drops in designing pulsed perforated-plate column

  1. Development of cost innovative BPs for a PEMFC stack for a 1 kW-class residential power generator (RPG) system

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Gil-yong; Jung, Min-kyung; Ryoo, Sung-nam; Ha, Sam-chul [Digital Appliance R and D, LG Electronics, Seoul 153-801 (Korea, Republic of); Park, Myung-seok [LG Solar Energy, Seoul 150-721 (Korea, Republic of); Kim, Sunhoe [Department of New Energy and Resource Engineering, Sangji University, Wonju, Gangwon 220-702 (Korea, Republic of)


    In order to satisfy the demands of customers, cost innovation of fuel cell systems is required for the commercialization of the fuel cell. Since the stack is one of the most expensive parts in a fuel cell system, cost reduction of stack is required for fuel cell commercialization. For this effort stainless steel 304 sheets were etched for the flow field and then coated for corrosion resistance. This enables the development of highly cost-effective bipolar plates (BPs) for a Proton Exchange Membrane Fuel Cell (PEMFC) stack of a 1 kW-class for Residential Power Generator (RPG). LG Electronics (LGE) developed a metal stack of 64 cells with the developed BPs and achieved a performance rating of 0.75 V/cell at 200 mA/cm{sup 2}. LGE also achieved a stack volume reduction of 20% compared to a stack of the same specifications consisting of graphite material BPs. The volume decrease can be represented as a cost reduction. LGE achieved the very low cost innovation to 1 USD per cell with cells developed from etched metal BPs. LGE also achieved 500 h of operation with LGE's RPG system; this test is still ongoing. The degradation rate of the stack was 27 {mu}V/hr. The end of life of the stack was estimated at approximately 17,000 h. (author)

  2. Alumina column Rb-82 generator

    International Nuclear Information System (INIS)

    Yano, Y.; Roth, E.P.


    The use of an alumina column for the adsorption of radioactive Sr for the generator production of 75-sec 82 Rb was evaluated in both batches and column experiments using 85 Sr and cyclotron-produced 82 Sr. Comparisons of alumina, Bio-Rex 70 and Chelex 100 ion exchangers were made to determine Sr adsorption, 82 Rb elution yield and Sr breakthrough. The adsorption of Sr is similar for alumina and Chelex 100 but different for Bio-Rex 70. Alumina and Chelex 100 exhibit a small fraction of poorly bound Sr which appears as higher breakthrough in the early elution volumes. The remaining Sr activity is strongly bound to these ion exchangers and the breakthrough remains stable at a lower breakthrough value through a large number of elutions. Bio-Rex 70 on the other hand does not exhibit the poorly bound Sr fraction and the breakthrough of Sr remains the lowest of the three ion exchangers through a moderate number of elutions and then the Sr breakthrough gradually increases with each additional elution

  3. Calcium Isotope Analysis with "Peak Cut" Method on Column Chemistry (United States)

    Zhu, H.; Zhang, Z.; Liu, F.; Li, X.


    To eliminate isobaric interferences from elemental and molecular isobars (e.g., 40K+, 48Ti+, 88Sr2+, 24Mg16O+, 27Al16O+) on Ca isotopes during mass determination, samples should be purified through ion-exchange column chemistry before analysis. However, large Ca isotopic fractionation has been observed during column chemistry (Russell and Papanastassiou, 1978; Zhu et al., 2016). Therefore, full recovery during column chemistry is greatly needed, otherwise uncertainties would be caused by poor recovery (Zhu et al., 2016). Generally, matrix effects could be enhanced by full recovery, as other elements might overlap with Ca cut during column chemistry. Matrix effects and full recovery are difficult to balance and both need to be considered for high-precision analysis of stable Ca isotopes. Here, we investigate the influence of poor recovery on δ44/40Ca using TIMS with the double spike technique. The δ44/40Ca values of IAPSO seawater, ML3B-G and BHVO-2 in different Ca subcats (e.g., 0-20, 20-40, 40-60, 60-80, 80-100%) with 20% Ca recovery on column chemistry display limited variation after correction by the 42Ca-43Ca double spike technique with the exponential law. Notably, δ44/40Ca of each Ca subcut is quite consistent with δ44/40Ca of Ca cut with full recovery within error. Our results indicate that the 42Ca-43Ca double spike technique can simultaneously correct both of the Ca isotopic fractionation that occurred during column chemistry and thermal ionization mass spectrometry (TIMS) determination properly, because both of the isotopic fractionation occurred during analysis follow the exponential law well. Therefore, we propose the "peak cut" method on Ca column chemistry for samples with complex matrix effects. Briefly, for samples with low Ca contents, we can add the double spike before column chemistry, and only collect the middle of the Ca eluate and abandon the both sides of Ca eluate that might overlap with other elements (e.g., K, Sr). This method would

  4. Energy Efficient Clustering Based Network Protocol Stack for 3D Airborne Monitoring System

    Directory of Open Access Journals (Sweden)

    Abhishek Joshi


    Full Text Available Wireless Sensor Network consists of large number of nodes densely deployed in ad hoc manner. Usually, most of the application areas of WSNs require two-dimensional (2D topology. Various emerging application areas such as airborne networks and underwater wireless sensor networks are usually deployed using three-dimensional (3D network topology. In this paper, a static 3D cluster-based network topology has been proposed for airborne networks. A network protocol stack consisting of various protocols such as TDMA MAC and dynamic routing along with services such as time synchronization, Cluster Head rotation, and power level management has been proposed for this airborne network. The proposed protocol stack has been implemented on the hardware platform consisting of number of TelosB nodes. This 3D airborne network architecture can be used to measure Air Quality Index (AQI in an area. Various parameters of network such as energy consumption, Cluster Head rotation, time synchronization, and Packet Delivery Ratio (PDR have been analyzed. Detailed description of the implementation of the protocol stack along with results of implementation has been provided in this paper.

  5. Simultaneous stack-gas scrubbing and waste water treatment (United States)

    Poradek, J. C.; Collins, D. D.


    Simultaneous treatment of wastewater and S02-laden stack gas make both treatments more efficient and economical. According to results of preliminary tests, solution generated by stack gas scrubbing cycle reduces bacterial content of wastewater. Both processess benefit by sharing concentrations of iron.

  6. A Software Managed Stack Cache for Real-Time Systems

    DEFF Research Database (Denmark)

    Jordan, Alexander; Abbaspourseyedi, Sahar; Schoeberl, Martin


    In a real-time system, the use of a scratchpad memory can mitigate the difficulties related to analyzing data caches, whose behavior is inherently hard to predict. We propose to use a scratchpad memory for stack allocated data. While statically allocating stack frames for individual functions to ...

  7. Calculation of AC losses in large HTS stacks and coils

    DEFF Research Database (Denmark)

    Zermeno, Victor; Abrahamsen, Asger Bech; Mijatovic, Nenad


    In this work, we present a homogenization method to model a stack of HTS tapes under AC applied transport current or magnetic field. The idea is to find an anisotropic bulk equivalent for the stack of tapes, where the internal alternating structures of insulating, metallic, superconducting and su...

  8. Efficient Context Switching for the Stack Cache: Implementation and Analysis

    DEFF Research Database (Denmark)

    Abbaspourseyedi, Sahar; Brandner, Florian; Naji, Amine


    , the analysis of the stack cache was limited to individual tasks, ignoring aspects related to multitasking. A major drawback of the original stack cache design is that, due to its simplicity, it cannot hold the data of multiple tasks at the same time. Consequently, the entire cache content needs to be saved...

  9. Evaluation of Packed Distillation Columns I - Atmospheric Pressure

    National Research Council Canada - National Science Library

    Reynolds, Thaine


    .... Four column-packing combinations of the glass columns and four column-packing combinations of the steel columns were investigated at atmospheric pressure using a test mixture of methylcyclohexane...

  10. The behaviour of stacking fault energy upon interstitial alloying. (United States)

    Lee, Jee-Yong; Koo, Yang Mo; Lu, Song; Vitos, Levente; Kwon, Se Kyun


    Stacking fault energy is one of key parameters for understanding the mechanical properties of face-centered cubic materials. It is well known that the plastic deformation mechanism is closely related to the size of stacking fault energy. Although alloying is a conventional method to modify the physical parameter, the underlying microscopic mechanisms are not yet clearly established. Here, we propose a simple model for determining the effect of interstitial alloying on the stacking fault energy. We derive a volumetric behaviour of stacking fault energy from the harmonic approximation to the energy-lattice curve and relate it to the contents of interstitials. The stacking fault energy is found to change linearly with the interstitial content in the usual low concentration domain. This is in good agreement with previously reported experimental and theoretical data.

  11. Direct methanol fuel cell stack based on MEMS technology (United States)

    Zhang, Yufeng; Tang, Xiaochuan; Yuan, Zhenyu; Liu, Xiaowei


    This paper presents a design configuration of silicon-based micro direct methanol fuel cell (DMFC) stack in a planar array. The integrated series connection is oriented in a "flip-flop" configuration with electrical interconnections made by thin-film metal layers that coat the flow channels etched in the silicon substrate. The configuration features small connection space and low contact resistance. The MEMS fabrication process was utilized to fabricate the silicon plates of DMFC stack. This DMFC stack with an active area of 64mm x 11mm was characterized at room temperature and normal atmosphere. Experimental results show that the prototype stack is able to generate an open-circuit voltage of 2.7V and a maximum power density of 2.2mW/cm2, which demonstrate the feasibility of this new DMFC stack configuration.

  12. Deformation Induced Microtwins and Stacking Faults in Aluminum Single Crystal (United States)

    Han, W. Z.; Cheng, G. M.; Li, S. X.; Wu, S. D.; Zhang, Z. F.


    Microtwins and stacking faults in plastically deformed aluminum single crystal were successfully observed by high-resolution transmission electron microscope. The occurrence of these microtwins and stacking faults is directly related to the specially designed crystallographic orientation, because they were not observed in pure aluminum single crystal or polycrystal before. Based on the new finding above, we propose a universal dislocation-based model to judge the preference or not for the nucleation of deformation twins and stacking faults in various face-centered-cubic metals in terms of the critical stress for dislocation glide or twinning by considering the intrinsic factors, such as stacking fault energy, crystallographic orientation, and grain size. The new finding of deformation induced microtwins and stacking faults in aluminum single crystal and the proposed model should be of interest to a broad community.

  13. Physical Sciences Laboratory 1 Rooftop Stack Mixing Study

    Energy Technology Data Exchange (ETDEWEB)

    Flaherty, Julia E. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Antonio, Ernest J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)


    To address concerns about worker exposures on the Physical Science Laboratory (PSL) rooftop, a tracer study was conducted to measure gaseous tracer concentrations downwind of six stacks on the southern half of the PSL building (PSL-1). These concerns were raised, in part, due to the non-standard configuration of the stacks on this building. Five of the six stacks were only about 8 feet tall, with one shorter stack that was essentially level with the roof deck. These stacks were reconfigured in August 2016, and these exhaust points on PSL-1 are now 18 feet tall. This report describes the objectives of the tracer tests performed on PSL-1, provides an overview of how the tests were executed, and presents results of the tests. The tests on the PSL rooftop were a follow-on project from a similar study performed on the LSL-II ventilation exhaust (Flaherty and Antonio, 2016).

  14. High Power, Repetitive, Stacked Blumlein Pulse Generators Commuted by a Single Switching Element (United States)

    Bhawalkar, Jayant Dilip

    In this work, the stacked Blumlein pulsers developed at the University of Texas at Dallas were characterized and shown to be versatile sources of pulse power for a variety of applications. These devices consisted of several triaxial Blumleins stacked in series at one end. The lines were charged in parallel and synchronously commuted repetitively with a single switching element at the other end. In this way, relatively low charging voltages were multiplied to give a high discharge voltage across an arbitrary load without the need for complex Marx bank circuitry. Several pulser parameters such as the number of stacked Blumlein lines, line configuration, type of switching element, and the length of the lines, were varied and the waveform characteristics were observed and analyzed. It was shown that these devices are capable of generating fast rising waveforms with a wide range of peak voltage and current values. The generation of high power waveforms with pulse durations in the range of 80-600 ns was demonstrated without degradation of the voltage gains. The results of this work indicated that unlike generators based on stacked transmission lines, the effects of parasitic modes were not appreciable for the stacked Blumlein pulsers. Opportunities for tactically packaging these pulsers were also investigated and a significant reduction in their size and weight was demonstrated. For this, dielectric lifetime and Blumlein spacing studies were performed on small scale prototypes. In addition to production of intense X-ray pulses, the possible applications for these novel pulsers include driving magnetrons for high power microwave generation, pumping laser media, or powering e-beam diodes. They could also serve as compact, tabletop sources of high power pulses for various research experiments.

  15. 3D modeling and simulation of 2G HTS stacks and coils

    International Nuclear Information System (INIS)

    Zermeño, Víctor M R; Grilli, Francesco


    Use of 2G HTS coated conductors in several power applications has become popular in recent years. Their large current density under high magnetic fields makes them suitable candidates for high power capacity applications such as stacks of tapes, coils, magnets, cables and current leads. For this reason, modeling and simulation of their electromagnetic properties is very desirable in the design and optimization processes. For many applications, when symmetries allow it, simple models consisting of 1D or 2D representations are well suited for providing a satisfying description of the problem at hand. However, certain designs such as racetrack coils and finite-length or non-straight stacks, do pose a 3D problem that cannot be easily reduced to a 2D configuration. Full 3D models have been developed, but their use for simulating superconducting devices is a very challenging task involving a large-scale computational problem. In this work, we present a new method to simulate the electromagnetic transient behavior of 2G HTS stacks and coils. The method, originally used to model stacks of straight superconducting tapes or circular coils in 2D, is now extended to 3D. The main idea is to construct an anisotropic bulk-like equivalent for the stack or coil, such that the geometrical layout of the internal alternating structures of insulating, metallic, superconducting and substrate layers is reduced while keeping the overall electromagnetic behavior of the original device. Besides the aforementioned interest in modeling and simulating 2G HTS coated conductors, this work provides a further step towards efficient 3D modeling and simulation of superconducting devices for large-scale applications. (paper)

  16. Reflector imaging by diffraction stacking with stacking velocity analysis; Jugo sokudo kaiseki wo tomonau sanran jugoho ni yoru hanshamen imaging

    Energy Technology Data Exchange (ETDEWEB)

    Matsushima, J.; Rokugawa, S.; Kato, Y. [The University of Tokyo, Tokyo (Japan). Faculty of Engineering; Yokota, T. [Japan National Oil Corp., Tokyo (Japan); Miyazaki, T. [Geological Survey of Japan, Tsukuba (Japan)


    Concerning seismic reflection survey for geometrical arrangement between pits, the scattering stacking method with stacking velocity analysis is compared with the CDP (common depth point horizontal stacking method). The advantages of the CDP supposedly include the following. Since it presumes an average velocity field, it can determine velocities having stacking effects. The method presumes stratification and, since such enables the division of huge quantities of observed data into smaller groups, more data can be calculated in a shorter time period. The method has disadvantages, attributable to its presuming an average velocity field, that accuracy in processing is lower when the velocity field contrast is higher, that accuracy in processing is low unless stratification is employed, and that velocities obtained from stacking velocity analysis are affected by dipped structures. Such shortcomings may be remedied in the scattering stacking method with stacking velocity analysis. Possibilities are that, as far as the horizontal reflection plane is concerned, it may yield stack records higher in S/N ratio than the CDP. Findings relative to dipped reflection planes will be introduced at the presentation. 6 refs., 12 figs.

  17. Oscillating water column structural model

    Energy Technology Data Exchange (ETDEWEB)

    Copeland, Guild [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Bull, Diana L [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Jepsen, Richard Alan [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Gordon, Margaret Ellen [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)


    An oscillating water column (OWC) wave energy converter is a structure with an opening to the ocean below the free surface, i.e. a structure with a moonpool. Two structural models for a non-axisymmetric terminator design OWC, the Backward Bent Duct Buoy (BBDB) are discussed in this report. The results of this structural model design study are intended to inform experiments and modeling underway in support of the U.S. Department of Energy (DOE) initiated Reference Model Project (RMP). A detailed design developed by Re Vision Consulting used stiffeners and girders to stabilize the structure against the hydrostatic loads experienced by a BBDB device. Additional support plates were added to this structure to account for loads arising from the mooring line attachment points. A simplified structure was designed in a modular fashion. This simplified design allows easy alterations to the buoyancy chambers and uncomplicated analysis of resulting changes in buoyancy.

  18. Agnostic stacking of intergalactic doublet absorption: measuring the Ne VIII population (United States)

    Frank, Stephan; Pieri, Matthew M.; Mathur, Smita; Danforth, Charles W.; Shull, J. Michael


    We present a blind search for doublet intergalactic metal absorption with a method dubbed `agnostic stacking'. Using a forward-modelling framework, we combine this with direct detections in the literature to measure the overall metal population. We apply this novel approach to the search for Ne VIII absorption in a set of 26 high-quality COS spectra. We probe to an unprecedented low limit of log N>12.3 at 0.47≤z ≤1.34 over a path-length Δz = 7.36. This method selects apparent absorption without requiring knowledge of its source. Stacking this mixed population dilutes doublet features in composite spectra in a deterministic manner, allowing us to measure the proportion corresponding to Ne VIII absorption. We stack potential Ne VIII absorption in two regimes: absorption too weak to be significant in direct line studies (12.3 13.7). We do not detect Ne VIII absorption in either regime. Combining our measurements with direct detections, we find that the Ne VIII population is reproduced with a power-law column density distribution function with slope β = -1.86 ^{+0.18 }_{ -0.26} and normalization log f_{13.7} = -13.99 ^{+0.20 }_{ -0.23}, leading to an incidence rate of strong Ne VIII absorbers dn/dz =1.38 ^{+0.97 }_{ -0.82}. We infer a cosmic mass density for Ne VIII gas with 12.3 < log N < 15.0 of Ω _{{{Ne {VIII}}}} = 2.2 ^{+1.6 }_{ _-1.2} × 10^{-8}, a value significantly lower that than predicted by recent simulations. We translate this density into an estimate of the baryon density Ωb ≈ 1.8 × 10-3, constituting 4 per cent of the total baryonic mass.

  19. Agnostic Stacking of Intergalactic Doublet Absorption: Measuring the Ne VIII Population (United States)

    Frank, Stephan; Pieri, Matthew M.; Mathur, Smita; Danforth, Charles W.; Michael Shull, J.


    We present a blind search for doublet intergalactic metal absorption with a method dubbed `agnostic stacking'. Using a forward-modelling framework we combine this with direct detections in the literature to measure the overall metal population. We apply this novel approach to the search for Ne VIII absorption in a set of 26 high-quality COS spectra. We probe to an unprecedented low limit of log N>12.3 at 0.47≤z ≤1.34 over a pathlength Δz = 7.36. This method selects apparent absorption without requiring knowledge of its source. Stacking this mixed population dilutes doublet features in composite spectra in a deterministic manner, allowing us to measure the proportion corresponding to Ne VIII absorption. We stack potential Ne VIII absorption in two regimes: absorption too weak to be significant in direct line studies (12.3 13.7). We do not detect Ne VIII absorption in either regime. Combining our measurements with direct detections, we find that the Ne VIII population is reproduced with a power law column density distribution function with slope β = -1.86+0.18-0.26 and normalisation log f_{13.7} = -13.99+0.20-0.23, leading to an incidence rate of strong Ne VIII absorbers dn/dz =1.38+0.97-0.82. We infer a cosmic mass density for Ne VIII gas with 12.3 < log N < 15.0 of Ω _{Ne VIII} = 2.2+1.6-1.2 × 10^{-8}, a value significantly lower that than predicted by recent simulations. We translate this density into an estimate of the baryon density Ωb ≈ 1.8 × 10-3, constituting 4% of the total baryonic mass.


    Bradley, J.G.


    An improved baffle plate construction to intimately mix immiscible liquid solvents for solvent extraction processes in a liquid-liquid pulse column is described. To prevent the light and heavy liquids from forming separate continuous homogeneous vertical channels through sections of the column, a baffle having radially placed rectangular louvers with deflection plates opening upon alternate sides of the baffle is placed in the column, normal to the axis. This improvement substantially completely reduces strippiig losses due to poor mixing.

  1. Structural design of isolated column footings

    Directory of Open Access Journals (Sweden)

    Fathi Abdrabbo


    The study showed that shear span to depth ratio of a footing and distributions of contact stress at footing–soil interface are key factors in the structural design of the footing. ECP203-11, ACI318-08, and EC2-2004 code provisions, underestimate the structural failure loads of isolated column footings, while BS 8110.1-1997 overpredicts the failure loads of isolated column footings, if punching provisions at perimeter of column are pulled out from the code.

  2. Black Hole Spectroscopy with Coherent Mode Stacking. (United States)

    Yang, Huan; Yagi, Kent; Blackman, Jonathan; Lehner, Luis; Paschalidis, Vasileios; Pretorius, Frans; Yunes, Nicolás


    The measurement of multiple ringdown modes in gravitational waves from binary black hole mergers will allow for testing the fundamental properties of black holes in general relativity and to constrain modified theories of gravity. To enhance the ability of Advanced LIGO/Virgo to perform such tasks, we propose a coherent mode stacking method to search for a chosen target mode within a collection of multiple merger events. We first rescale each signal so that the target mode in each of them has the same frequency and then sum the waveforms constructively. A crucial element to realize this coherent superposition is to make use of a priori information extracted from the inspiral-merger phase of each event. To illustrate the method, we perform a study with simulated events targeting the ℓ=m=3 ringdown mode of the remnant black holes. We show that this method can significantly boost the signal-to-noise ratio of the collective target mode compared to that of the single loudest event. Using current estimates of merger rates, we show that it is likely that advanced-era detectors can measure this collective ringdown mode with one year of coincident data gathered at design sensitivity.

  3. Stacking faults in austempered ductile iron

    Energy Technology Data Exchange (ETDEWEB)

    Hermida, J.D. [CNEA, San Martin (Argentina). Dept. de Materiales


    During last decade, Austempered Ductile Iron (ADI) has been successfully used as an acceptable replacement material for steel in many applications, due to the relatively high strength and reasonable ductility obtained. These properties are the result of the special microstructure exhibited by this material at the end of the upper bainite reaction: ferrite platelets surrounded by high carbon stabilized austenite. However, at the beginning of the austempering treatment, the existence of interdendritic low carbon austenite is revealed by its transformation to martensite when cooling the sample or during subsequent deformation. The completion of the upper bainite reaction is of decisive importance to mechanical properties because the remaining martensite reduces ductility. It was observed that the rate of the upper bainite reaction is governed by the carbon content difference between the low and high carbon austenites. The carbon content is obtained by the lattice parameter measurement, because there exists a known expression that relates both magnitudes. Several works have used X-ray diffraction to measure the lattice parameter and phase concentrations as a function of austempering time. In these works, the lattice parameters were obtained directly from the {l_brace}220{r_brace} and {l_brace}311{r_brace} peaks position. The purpose of this work is to show more precise lattice parameters measurement and, very closely related to this, the existence of stacking faults in austenite, even at times within the processing window.

  4. ATLAS software stack on ARM64

    CERN Document Server

    Smith, Joshua Wyatt; The ATLAS collaboration


    The ATLAS experiment explores new hardware and software platforms that, in the future, may be more suited to its data intensive workloads. One such alternative hardware platform is the ARM architecture, which is designed to be extremely power efficient and is found in most smartphones and tablets. CERN openlab recently installed a small cluster of ARM 64-bit evaluation prototype servers. Each server is based on a single-socket ARM 64-bit system on a chip, with 32 Cortex-A57 cores. In total, each server has 128 GB RAM connected with four fast memory channels. This paper reports on the port of the ATLAS software stack onto these new prototype ARM64 servers. This included building the "external" packages that the ATLAS software relies on. Patches were needed to introduce this new architecture into the build as well as patches that correct for platform specific code that caused failures on non-x86 architectures. These patches were applied such that porting to further platforms will need no or only very little adj...

  5. Long Duration Balloon Charge Controller Stack Integration (United States)

    Clifford, Kyle

    NASA and the Columbia Scientific Balloon Facility are interested in updating the design of the charge controller on their long duration balloon (LDB) in order to enable the charge controllers to be directly interfaced via RS232 serial communication by a ground testing computers and the balloon's flight computer without the need to have an external electronics stack. The design involves creating a board that will interface with the existing boards in the charge controller in order to receive telemetry from and send commands to those boards, and interface with a computer through serial communication. The inputs to the board are digital status inputs indicating things like whether the photovoltaic panels are connected or disconnected; and analog inputs with information such as the battery voltage and temperature. The outputs of the board are 100ms duration command pulses that will switch relays that do things like connect the photovoltaic panels. The main component of this design is a PIC microcontroller which translates the outputs of the existing charge controller into serial data when interrogated by a ground testing or flight computer. Other components involved in the design are an AD7888 12-bit analog to digital converter, a MAX3232 serial transceiver, various other ICs, capacitors, resistors, and connectors.

  6. Lithiation-induced shuffling of atomic stacks

    KAUST Repository

    Nie, Anmin


    In rechargeable lithium-ion batteries, understanding the atomic-scale mechanism of Li-induced structural evolution occurring at the host electrode materials provides essential knowledge for design of new high performance electrodes. Here, we report a new crystalline-crystalline phase transition mechanism in single-crystal Zn-Sb intermetallic nanowires upon lithiation. Using in situ transmission electron microscopy, we observed that stacks of atomic planes in an intermediate hexagonal (h-)LiZnSb phase are "shuffled" to accommodate the geometrical confinement stress arising from lamellar nanodomains intercalated by lithium ions. Such atomic rearrangement arises from the anisotropic lithium diffusion and is accompanied by appearance of partial dislocations. This transient structure mediates further phase transition from h-LiZnSb to cubic (c-)Li2ZnSb, which is associated with a nearly "zero-strain" coherent interface viewed along the [001]h/[111]c directions. This study provides new mechanistic insights into complex electrochemically driven crystalline-crystalline phase transitions in lithium-ion battery electrodes and represents a noble example of atomic-level structural and interfacial rearrangements.

  7. Weyl magnons in noncoplanar stacked kagome antiferromagnets (United States)

    Owerre, S. A.


    Weyl nodes have been experimentally realized in photonic, electronic, and phononic crystals. However, magnonic Weyl nodes are yet to be seen experimentally. In this paper, we propose Weyl magnon nodes in noncoplanar stacked frustrated kagome antiferromagnets, naturally available in various real materials. Most crucially, the Weyl nodes in the current system occur at the lowest excitation and possess a topological thermal Hall effect, therefore they are experimentally accessible at low temperatures due to the population effect of bosonic quasiparticles. In stark contrast to other magnetic systems, the current Weyl nodes do not rely on time-reversal symmetry breaking by the magnetic order. Rather, they result from explicit macroscopically broken time reversal symmetry by the scalar spin chirality of noncoplanar spin textures and can be generalized to chiral spin liquid states. Moreover, the scalar spin chirality gives a real space Berry curvature which is not available in previously studied magnetic Weyl systems. We show the existence of magnon arc surface states connecting projected Weyl magnon nodes on the surface Brillouin zone. We also uncover the first realization of triply-degenerate nodal magnon point in the noncollinear regime with zero scalar spin chirality.

  8. Vibration damping in bolted friction beam-columns


    Bournine, H.; Wagg, D.J.; Neild, S.A.


    In this paper we examine the use of dynamic friction within a bolted structure to improve damping properties of the structure. The structure considered for this paper consists of two steel beam-columns bolted together allowing dynamic friction to occur at the interface. This paper presents an analysis of the behaviour of the structure and the effect of friction on its dynamics. It also presents an analysis of the energy dissipation in the structure by means of friction and the optimization of...

  9. Thermally stable dexsil-400 glass capillary columns

    International Nuclear Information System (INIS)

    Maskarinec, M.P.; Olerich, G.


    The factors affecting efficiency, thermal stability, and reproducibility of Dexsil-400 glass capillary columns for gas chromatography in general, and for polycyclic aromatic hydrocarbons (PAHs) in particular were investigated. Columns were drawn from Kimble KG-6 (soda-lime) glass or Kimox (borosilicate) glass. All silylation was carried out at 200 0 C. Columns were coated according to the static method. Freshly prepared, degassed solutions of Dexsil-400 in pentane or methylene chloride were used. Thermal stability of the Dexsil 400 columns with respect to gas chromatography/mass spectrometry (GC/MS) were tested. Column-to-column variability is a function of each step in the fabrication of the columns. The degree of etching, extent of silylation, and stationary phase film thickness must be carefully controlled. The variability in two Dexsil-400 capillary column prepared by etching, silylation with solution of hexa methyl disilazone (HMDS), and static coating is shown and also indicates the excellent selectivity of Dexsil-400 for the separation of alkylated aromatic compounds. The wide temperature range of Dexsil-400 and the high efficiency of the capillary columns also allow the analysis of complex mixtures with minimal prefractionation. Direct injection of a coal liquefaction product is given. Analysis by GC/MS indicated the presence of parent PAHs, alkylated PAHs, nitrogen and sulfur heterocycles, and their alkylated derivatives. 4 figures

  10. Preparation and application of hydrophilic monolithic columns. (United States)

    Jiang, Zhengjin; Smith, Norman William; Liu, Zhenghua


    Hydrophilic interaction chromatography (HILIC) has experienced increasing attention in recent years. Much research has been carried out in the area of HILIC separation mechanisms, column techniques and applications. Because of their good permeability, low resistance to mass transfer and easy preparation within capillaries, hydrophilic monolithic columns represent a trend among novel HILIC column techniques. This review attempts to present an overview of the preparation and applications of HILIC monolithic columns carried out in the past decade. The separation mechanism of various hydrophilic monolithic stationary phases is also reviewed. Copyright © 2011 Elsevier B.V. All rights reserved.

  11. Stud Reinforcement in Beam-Column Joints under Seismic Loads (United States)

    Ibrahim, Hatem Hassan Ali

    Current codes recommend large amounts of shear reinforcement for reinforced concrete beam-column joints causing significant congestion. This research aims at investigating experimentally and numerically the efficiency of using studs with a head at each end in lieu of conventional closed hoops in reinforced concrete beam-column joints. The proposed reinforcement reduces congestion and ensures easier assembly of the reinforcing cage, saving labour cost and enhancing performance of the joint. Based on this research, a recommended arrangement and detailing of headed studs and their design for exterior beam-column joint are presented. The experimental investigation consisted of testing ten full-scale beam-column joint specimens under quasi-static cyclic loading. The specimens represented an exterior beam-column joint subassembly isolated at the points of contra-flexure from a typical multi-storey, multi-bay reinforced concrete frame. A test setup was developed to simulate the lateral inter-storey drift. The test parameters included: the type, arrangement and amount of shear reinforcement, the load history and rate of loading, and the amount of reinforcement for out-of-plane confinement of the joint. Envelopes of the hysteretic behaviour of the specimens and the joint deformation under shear stress are presented. The stiffness degradation, the strain levels in the joint reinforcement, the contribution of joint, beam, and column to the inter-storey drift, and the energy dissipation were compared. All the test specimens reinforced with headed studs in the joint achieved considerable enhancement in their behaviour under cyclic loads and exhibited a performance close to that of a joint reinforced with closed hoops and cross ties according to the code. All the specimens with adequate out-of-plane confinement had an equivalent behaviour compared with the code-based specimen and achieved a desirable mode of failure. Use of double-headed studs proved to be a viable option for

  12. Efficiency of Polymer Electrolyte Membrane Fuel Cell Stack

    Directory of Open Access Journals (Sweden)

    Hans Bosma


    Full Text Available This paper applies a feedforward control of optimal oxygen excess ratio that maximize net power (improve efficiency of a NedStack P8.0-64 PEM fuel cell stack (FCS system. Net powers profile as a function of oxygen excess ratio for some points of operation are analyzed by using FCS model. The relationships between stack current and the corresponding control input voltage that gives an optimal oxygen excess ratio are used to design a feedforward control scheme. The results of this scheme are compared to the results of a feedforward control using a constant oxygen excess ratio. Simulation results show that optimal oxygen excess ratio improves fuel cell performance compared to the results of constant oxygen excess ratio. The same procedures are performed experimentally for the FCS system. The behaviour of the net power of the fuel cell stack with respect to the variation of oxygen excess ratio is analyzed to obtain optimal values. Data of stack current and the corresponding voltage input to the compressor that gives optimal values of oxygen excess ratio are used to develop a feedforward control. Feedforward control based on constant and optimal oxygen excess ratio control, are implemented in the NedStack P8.0-64 PEM fuel cell stack system by using LabVIEW. Implementation results shows that optimal oxygen excess ratio control improves the fuel cell performance compared to the constant oxygen excess ratio control.

  13. Column Chromatography To Obtain Organic Cation Sorption Isotherms. (United States)

    Jolin, William C; Sullivan, James; Vasudevan, Dharni; MacKay, Allison A


    Column chromatography was evaluated as a method to obtain organic cation sorption isotherms for environmental solids while using the peak skewness to identify the linear range of the sorption isotherm. Custom packed HPLC columns and standard batch sorption techniques were used to intercompare sorption isotherms and solid-water sorption coefficients (Kd) for four organic cations (benzylamine, 2,4-dichlorobenzylamine, phenyltrimethylammonium, oxytetracycline) with two aluminosilicate clay minerals and one soil. A comparison of Freundlich isotherm parameters revealed isotherm linearity or nonlinearity was not significantly different between column chromatography and traditional batch experiments. Importantly, skewness (a metric of eluting peak symmetry) analysis of eluting peaks can establish isotherm linearity, thereby enabling a less labor intensive means to generate the extensive data sets of linear Kd values required for the development of predictive sorption models. Our findings clearly show that column chromatography can reproduce sorption measures from conventional batch experiments with the benefit of lower labor-intensity, faster analysis times, and allow for consistent sorption measures across laboratories with distinct chromatography instrumentation.

  14. Thickness Dependent Interlayer Magnetoresistance in Multilayer Graphene Stacks

    Directory of Open Access Journals (Sweden)

    S. C. Bodepudi


    Full Text Available Chemical Vapor Deposition grown multilayer graphene (MLG exhibits large out-of-plane magnetoresistance due to interlayer magnetoresistance (ILMR effect. It is essential to identify the factors that influence this effect in order to explore its potential in magnetic sensing and data storage applications. It has been demonstrated before that the ILMR effect is sensitive to the interlayer coupling and the orientation of the magnetic field with respect to the out-of-plane (c-axis direction. In this work, we investigate the role of MLG thickness on ILMR effect. Our results show that the magnitude of ILMR effect increases with the number of graphene layers in the MLG stack. Surprisingly, thicker devices exhibit field induced resistance switching by a factor of at least ~107. This effect persists even at room temperature and to our knowledge such large magnetoresistance values have not been reported before in the literature at comparable fields and temperatures. In addition, an oscillatory MR effect is observed at higher field values. A physical explanation of this effect is presented, which is consistent with our experimental scenario.

  15. Exact Solutions to the Double Travelling Salesman Problem with Multiple Stacks

    DEFF Research Database (Denmark)

    Petersen, Hanne L.; Archetti, Claudia; Speranza, M. Grazia


    to a customer in a delivery region. The vehicle available for the transportation in each region carries a container. The container is organized in rows of given length. Each row is handled independently from the others according to a LIFO (Last In First Out) stack policy. The DTSPMS problem consists......In this paper we present mathematical programming formulations and solution approaches for the optimal solution of the Double Travelling Salesman Problem with Multiple Stacks (DTSPMS). A set of orders is given, each one requiring transportation of one item from a customer in a pickup region...... of determining the pickup tour, the loading plan of the container and the delivery tour in such a way that the total length of the two tours is minimized. The formulations are based on different modelling ideas and each formulation gives rise to a specific solution approach. We present computational results...

  16. Coherent radiation characteristics of modulated electron bunch formed in stack of two plates (United States)

    Gevorgyan, H. L.; Gevorgian, L. A.


    The present article is devoted to the radiation from the electron bunch with modulated density passes through the stack consisting of two plates with different thicknesses and electrodynamic properties. The new elegant expression for the frequency-angular distribution of transition radiation is obtained. Using the existence of resonant frequency at which the longitudinal form-factor of bunch not suppresses radiation coherence and choosing parameters for the stack of plates, one can also avoid suppression of the radiation coherence by transverse form-factor of bunch. The radiation from a bunch with modulated density in the process SASE (self-amplified spontaneous emission) FEL can be partially coherent at a resonant frequency. Then the intense sub monochromatic beam of X-ray photons is formed. On the other hand one can define an important parameter of the bunch density modulation depth which is unknown to this day.

  17. Post-Stack Seismic Data Enhancement of Thrust-Belt Area, Sabah Basin (United States)

    Latiff, A. H. Abdul; Jamaludin, S. N. F.; Zakariah, M. N. A.


    In this paper, an integrated post-stack seismic data processing and interpretation for a complex thrust-belt area was proposed. The sequence was suggested due to poor seismic data quality of the Sabah basin area that was obtained after a pre-stack data processing sequences. This basin consists of a complex geological setting such as thrust-belt with steep dip reflector which is the main features of the region. In this paper, we outlined several methods used in the seismic data processing and interpretation such as amplitude recovery and frequency filtering for enhancing seismic data quality, and relative acoustic impedance, structural smoothing and wavelet coherency were used for attribute analysis. The outcome from this research aims at illuminating the hidden structures such as proper beds termination and faults systems that was heavily affected by low signal-to-noise ratio.

  18. Charliecloud: Unprivileged containers for user-defined software stacks in HPC

    Energy Technology Data Exchange (ETDEWEB)

    Priedhorsky, Reid [Los Alamos National Laboratory; Randles, Timothy C. [Los Alamos National Laboratory


    Supercomputing centers are seeing increasing demand for user-defined software stacks (UDSS), instead of or in addition to the stack provided by the center. These UDSS support user needs such as complex dependencies or build requirements, externally required configurations, portability, and consistency. The challenge for centers is to provide these services in a usable manner while minimizing the risks: security, support burden, missing functionality, and performance. We present Charliecloud, which uses the Linux user and mount namespaces to run industry-standard Docker containers with no privileged operations or daemons on center resources. Our simple approach avoids most security risks while maintaining access to the performance and functionality already on offer, doing so in less than 500 lines of code. Charliecloud promises to bring an industry-standard UDSS user workflow to existing, minimally altered HPC resources.

  19. Consolidity: Stack-based systems change pathway theory elaborated

    Directory of Open Access Journals (Sweden)

    Hassen Taher Dorrah


    Full Text Available This paper presents an elaborated analysis for investigating the stack-based layering processes during the systems change pathway. The system change pathway is defined as the path resulting from the combinations of all successive changes induced on the system when subjected to varying environments, activities, events, or any excessive internal or external influences and happenings “on and above” its normal stands, situations or set-points during its course of life. The analysis is essentially based on the important overall system paradigm of “Time driven-event driven-parameters change”. Based on this paradigm, it is considered that any affected activity, event or varying environment is intelligently self-recorded inside the system through an incremental consolidity-scaled change in system parameters of the stack-based layering types. Various joint stack-based mathematical and graphical approaches supported by representable case studies are suggested for the identification, extraction, and processing of various stack-based systems changes layering of different classifications and categorizations. Moreover, some selected real life illustrative applications are provided to demonstrate the (infinite stack-based identification and recognition of the change pathway process in the areas of geology, archeology, life sciences, ecology, environmental science, engineering, materials, medicine, biology, sociology, humanities, and other important fields. These case studies and selected applications revealed that there are general similarities of the stack-based layering structures and formations among all the various research fields. Such general similarities clearly demonstrate the global concept of the “fractals-general stacking behavior” of real life systems during their change pathways. Therefore, it is recommended that concentrated efforts should be expedited toward building generic modular stack-based systems or blocks for the mathematical

  20. Loop Entropy Assists Tertiary Order: Loopy Stabilization of Stacking Motifs

    Directory of Open Access Journals (Sweden)

    Daniel P. Aalberts


    Full Text Available The free energy of an RNA fold is a combination of favorable base pairing and stacking interactions competing with entropic costs of forming loops. Here we show how loop entropy, surprisingly, can promote tertiary order. A general formula for the free energy of forming multibranch and other RNA loops is derived with a polymer-physics based theory. We also derive a formula for the free energy of coaxial stacking in the context of a loop. Simulations support the analytic formulas. The effects of stacking of unpaired bases are also studied with simulations.

  1. Mixed Mechanism of Lubrication by Lipid Bilayer Stacks. (United States)

    Boţan, Alexandru; Joly, Laurent; Fillot, Nicolas; Loison, Claire


    Although the key role of lipid bilayer stacks in biological lubrication is generally accepted, the mechanisms underlying their extreme efficiency remain elusive. In this article, we report molecular dynamics simulations of lipid bilayer stacks undergoing load and shear. When the hydration level is reduced, the velocity accommodation mechanism changes from viscous shear in hydration water to interlayer sliding in the bilayers. This enables stacks of hydrated lipid bilayers to act as efficient boundary lubricants for various hydration conditions, structures, and mechanical loads. We also propose an estimation for the friction coefficient; thanks to the strong hydration forces between lipid bilayers, the high local viscosity is not in contradiction with low friction coefficients.

  2. On $k$-stellated and $k$-stacked spheres


    Bagchi, Bhaskar; Datta, Basudeb


    We introduce the class $\\Sigma_k(d)$ of $k$-stellated (combinatorial) spheres of dimension $d$ ($0 \\leq k \\leq d + 1$) and compare and contrast it with the class ${\\cal S}_k(d)$ ($0 \\leq k \\leq d$) of $k$-stacked homology $d$-spheres. We have $\\Sigma_1(d) = {\\cal S}_1(d)$, and $\\Sigma_k(d) \\subseteq {\\cal S}_k(d)$ for $d \\geq 2k - 1$. However, for each $k \\geq 2$ there are $k$-stacked spheres which are not $k$-stellated. The existence of $k$-stellated spheres which are not $k$-stacked remains...

  3. Stacking by electroinjection with discontinuous buffers in capillary zone electrophoresis. (United States)

    Shihabi, Zak K


    The work presented here demonstrates that electroinjection can be performed using discontinuous buffers, which can result in better stacking than that obtained by hydrodynamic injection. The sample can be concentrated at the tip of the capillary leaving practically the whole capillary for sample separation. This results in several advantages, such as better sample concentration, higher plate number and shorter time of stacking. However, sample introduction by electromigration is suited for samples free or low in salt content. Samples, which are high in salt content, are better introduced by the hydrodynamic injection for stacking by the discontinuous buffers. Different simple methods to introduce the discontinuity in the buffer for electroinjection are discussed.

  4. Optimized stacked RADFETs for milli-rad dose measurement

    International Nuclear Information System (INIS)

    O'Connell, B.; Lane, B.; Mohammadzadeh, A.


    This paper details the improvements in the design of stacked RADFETs for increased radiation sensitivity. The issues of high read-out voltage has been shown to be a draw-back. It is the body (bulk)effect factor that is responsible for the increased overall stack Threshold voltage (V T ), which is greater than the sum of the individual devices V T . From extensive process and device simulation and resultant circuit simulation, modified stack structures have been proposed and designed. New and exciting result of lower initial (pre-irradiation) output voltage as well as increased radiation sensitivity will be presented. (author)

  5. The fate of the submarine ikaite tufa columns in southwest Greenland under changing climate conditions

    DEFF Research Database (Denmark)

    Hansen, Marc O.; Buchardt, Bjørn; Kühl, Michael


    carbonate tufa columns. Here, ikaite is formed as a result of submarine spring water mixing with cold seawater. As ikaite disintegrates at temperatures above 6–7uC, it has been speculated that global warming could endanger this unique habitat as well as other sites. In Ikka Fjord in situ water chemistry...... at the top causes passive drag of seawater into the porous ikaite matrix, leading to a mixing layer several centimeters thick that has pH values intermediate to the spring water in the column and the surrounding seawater. We conclude that the main part of the columns, consisting of fossilized ikaite...... (inverted to calcite) partly sealed by calcifying coralline algae and with year-round flow of alkaline freshwater through distinct channels, are resistant to warming. In the more diffuse top part of the columns, the formation of ikaite, and thus column growth, will be limited in the future due to increased...

  6. Consistency argued students of fluid (United States)

    Viyanti; Cari; Suparmi; Winarti; Slamet Budiarti, Indah; Handika, Jeffry; Widyastuti, Fatma


    Problem solving for physics concepts through consistency arguments can improve thinking skills of students and it is an important thing in science. The study aims to assess the consistency of the material Fluid student argmentation. The population of this study are College students PGRI Madiun, UIN Sunan Kalijaga Yogyakarta and Lampung University. Samples using cluster random sampling, 145 samples obtained by the number of students. The study used a descriptive survey method. Data obtained through multiple-choice test and interview reasoned. Problem fluid modified from [9] and [1]. The results of the study gained an average consistency argmentation for the right consistency, consistency is wrong, and inconsistent respectively 4.85%; 29.93%; and 65.23%. Data from the study have an impact on the lack of understanding of the fluid material which is ideally in full consistency argued affect the expansion of understanding of the concept. The results of the study as a reference in making improvements in future studies is to obtain a positive change in the consistency of argumentations.

  7. Fabrication of single-walled carbon nanohorns incorporated a monolithic column for capillary electrochromatography. (United States)

    Zhao, Hongyan; Wang, Yizhou; Cheng, Heyong; Wang, Yuanchao


    Single-walled carbon nanohorns have received great interest for their unique properties and diverse potential applications. Herein, we demonstrated the feasibility of single-walled carbon nanohorns incorporated poly(styrene-divinylbenzene) monolith as the stationary phase for capillary electrochromatography, which were prepared by one-step in situ copolymerization. Single-walled carbon nanohorns were dispersed in styrene to give a stable and homogeneous suspension. The monolithic column gave effective separation for a wide range of aromatic compounds, which was based on hydrophobicity and π-π electrostatic stacking of single-walled carbon nanohorns. The precisions of migration time and peak area varied in the ranges of 1.4-1.9% for intraday trials and 1.7-3.5% for interday trials, and 3.2-6.7% for intraday trials and 4.1-7.4% for interday trials, and 3.6-7.2% for inter-column trials and 5.2-21.3% for inter-column trials, respectively, indicating the good reproducibility of single-walled carbon nanohorns embedded monolithic columns. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Application of Derrick Corporation's stack sizer technology for slimes reduction in 6 inch clean coal hydrocyclone circuits

    Energy Technology Data Exchange (ETDEWEB)

    Brodzik, P.


    The article discusses the successful introduction of Derrick Corporation's Stack Sizer technology for removing minus 200 mesh slimes from 6-inch coal hydrocyclone underflow prior to froth flotation or dewatering by screen bowl centrifuges. In 2006, the James River Coal Company selected the Stack Sizer fitted with Derrick 150 micron and 100 micron urethane screen panels for removal of the minus 100 mesh high ash clay fraction from the clean coal spiral product circuits. After this application proved successful, Derrick Corporation introduced new 75 micron urethane screen panels for use on the Stack Sizer. Evaluation of feed slurry to flotation cells and screen bowl centrifuges showed significant amounts of minus 75 micron that could potentially be removed by efficient screening technology. Removal of the minus 75 micron fraction was sought to reduce ash and moisture content of the final clean coal product. Full-scale lab tests confirmed that the Stack Sizer fitted with Derrick 75 micron urethane screen panels consistently reduced the minus 75 micron percentage in coal slurry from 6-inch clean coal hydrocyclone underflow that is approximately 15 to 20% solid by-weight and 30 to 60% minus 75 micron to a clean coal fraction that is approximately 13 to 16% minus 75 micron. As a result total ash is reduced from approximately 36 to 38% in the hydrocyclone underflow to 14 to 16% in the oversize product fraction form the Stack Sizers. 1 fig., 2 tabs., 5 photos.

  9. Planar air-breathing micro-direct methanol fuel cell stacks based on micro-electronic-mechanical-system technology (United States)

    Cao, Jianyu; Zou, Zhiqing; Huang, Qinghong; Yuan, Ting; Li, Zhilin; Xia, Baojia; Yang, Hui

    To meet the demands for high power micro-electronic devices, two silicon-based micro-direct methanol fuel cell (μDMFC) stacks consisting of six individual cells with two different anode flow fields were designed, fabricated and evaluated. Micro-electronic-mechanical-system (MEMS) technology was used to fabricate both flow field plate and fuel distribution plate on the silicon wafer. Experimental results show that either an individual cell or a stack with double serpentine-type flow fields presents better cell performance than those with pin-type flow fields. A μDMFC stack with double serpentine-type flow fields generates a peak output power of ca. 151 mW at a working voltage of 1.5 V, corresponding to an average power density of ca. 17.5 mW cm -2, which is ca. 20.7% higher than that with pin-type flow fields. The volume and weight of the stacks are only 5.3 cm 3 and 10.7 g, respectively. Such small stacks could be used as power sources for micro-electronic devices.

  10. Coordinating user interfaces for consistency

    CERN Document Server

    Nielsen, Jakob


    In the years since Jakob Nielsen's classic collection on interface consistency first appeared, much has changed, and much has stayed the same. On the one hand, there's been exponential growth in the opportunities for following or disregarding the principles of interface consistency-more computers, more applications, more users, and of course the vast expanse of the Web. On the other, there are the principles themselves, as persistent and as valuable as ever. In these contributed chapters, you'll find details on many methods for seeking and enforcing consistency, along with bottom-line analys

  11. Gaseous carbon dioxide absorbing column

    International Nuclear Information System (INIS)

    Harashina, Heihachi.


    The absorbing column of the present invention comprises a cyclone to which CO 2 gas and Ca(OH) 2 are blown to form CaCO 3 , a water supply means connected to an upper portion of the cyclone for forming a thin water membrane on the inner wall thereof, and a water processing means connected to a lower portion of the cyclone for draining water incorporating CaCO 3 . If a mixed fluid of CO 2 gas and Ca(OH) 2 is blown in a state where a flowing water membrane is formed on the inner wall of the cyclone, formation of CaCO 3 is promoted also in the inside of the cyclone in addition to the formation of CaCO 3 in the course of blowing. Then, formed CaCO 3 is discharged from the lower portion of the cyclone together with downwardly flowing water. With such procedures, solid contents such as CaCO 3 separated at the inner circumferential wall are sent into the thin water membrane, adsorbed and captured, and the solid contents are successively washed out, so that a phenomenon that the solid contents deposit and grow on the inner wall of the cyclone can be prevented effectively. (T.M.)

  12. Column: Factors Affecting Data Decay

    Directory of Open Access Journals (Sweden)

    Kevin Fairbanks


    Full Text Available In nuclear physics, the phrase decay rate is used to denote the rate that atoms and other particles spontaneously decompose. Uranium-235 famously decays into a variety of daughter isotopes including Thorium and Neptunium, which themselves decay to others. Decay rates are widely observed and wildly different depending on many factors, both internal and external. U-235 has a half-life of 703,800,000 years, for example, while free neutrons have a half-life of 611 seconds and neutrons in an atomic nucleus are stable.We posit that data in computer systems also experiences some kind of statistical decay process and thus also has a discernible decay rate. Like atomic decay, data decay fluctuates wildly. But unlike atomic decay, data decay rates are the result of so many different interplaying processes that we currently do not understand them well enough to come up with quantifiable numbers. Nevertheless, we believe that it is useful to discuss some of the factors that impact the data decay rate, for these factors frequently determine whether useful data about a subject can be recovered by forensic investigation.(see PDF for full column

  13. Rasch models with exchangeable rows and columns

    DEFF Research Database (Denmark)

    Lauritzen, Steffen Lilholt

    The article studies distributions of doubly infinite binary matrices with exchangeable rows and columns which satify the further property that the probability of any $m \\times n$ submatrix is a function of the row- and column sums of that matrix. We show that any such distribution is a (unique...

  14. Interaction Buckling Experiments of Box columns


    永藤, 寿宮


    Box sections present very interesting properties in the field of compressed elements. The purpose of this experiment is to supply experimental data of interaction buckling (overall and local buckling). Test columns are classified into 4 types according to those columns length. Support conditions are pin-ended type by using new developed bowl shoe.

  15. Fringing-field effects in acceleration columns

    International Nuclear Information System (INIS)

    Yavor, M.I.; Weick, H.; Wollnik, H.


    Fringing-field effects in acceleration columns are investigated, based on the fringing-field integral method. Transfer matrices at the effective boundaries of the acceleration column are obtained, as well as the general transfer matrix of the region separating two homogeneous electrostatic fields with different field strengths. The accuracy of the fringing-field integral method is investigated

  16. Cross-column prediction of gas-chromatographic retention of polybrominated diphenyl ethers. (United States)

    D'Archivio, Angelo Antonio; Giannitto, Andrea; Maggi, Maria Anna


    In this paper, we predict the retention of polybrominated diphenyl ethers (PBDEs) in capillary gas-chromatography (GC) within a useful range of separation conditions. In a first stage of this study, quantitative structure-retention relationships (QSRRs) of PBDEs in six stationary phases with different polarity are established. The single-column QSRR models are generated using the retention data of 126 PBDE congeners by multilinear regression (MLR) coupled to genetic algorithm variable selection applied to a large set of theoretical molecular descriptors of different classes. A quite accurate fitting of experimental retentions is obtained for each of the six GC columns adopting five molecular descriptors. In a further step of this work six molecular descriptors were extracted within the set of molecular descriptors (17 variables) involved in the various single-column QSRRs. The selected molecular descriptors are combined with observed retentions of ten representative PBDEs, adopted as descriptors of the GC system. These quantities are considered as the independent variables of a multiple-column retention model able to simultaneously relate GC retention to PBDE molecular structure and kind of column. The quantitative structure/column-retention relationship is established using a multi-layer artificial neural network (ANN) as regression tool. To optimise the ANN model, a validation set is generated by selecting two out of the six calibration columns. Splitting of columns between training and validation sets, as well as selection of PBDE congeners to be used as column descriptors, is performed with the help of a principal component analysis on the retention data. Cross-column predictive performance of the final model is tested on a large external set consisting of retention data of 180 PBDEs collected in four separation conditions different from those considered in model calibration (different columns and/or temperature program). Copyright © 2013 Elsevier B.V. All

  17. Consistent Regulatory Policy under Uncertainty


    Michael J. Brennan; Eduardo S. Schwartz


    This article is concerned with the effects of regulation on the risk and value of the regulated firm in a dynamic context. Current regulatory practice is shown to be logically deficient, since it ignores the effect of regulatory policy on the cost of capital and therefore on the appropriate allowed rate of return. A notion of consistency in regulatory policy is developed, and it is shown how consistent regulatory policies may be implemented once the valuation problem is solved.

  18. Self-consistent quark bags

    International Nuclear Information System (INIS)

    Rafelski, J.


    After an introductory overview of the bag model the author uses the self-consistent solution of the coupled Dirac-meson fields to represent a bound state of strongly ineteracting fermions. In this framework he discusses the vivial approach to classical field equations. After a short description of the used numerical methods the properties of bound states of scalar self-consistent Fields and the solutions of a self-coupled Dirac field are considered. (HSI) [de

  19. Planktonic Marine Luminous Bacteria: Species Distribution in the Water Column


    Ruby, E. G.; Greenberg, E. P.; Hastings, J. W.


    Luminous bacteria were isolated from oceanic water samples taken throughout the upper 1,000 m and ranged in density from 0.4 to 30 colony-forming units per 100 ml. Generally, two peaks in abundance were detected: one in the upper 100 m of the water column, which consisted primarily of Beneckea spp.; and a second between 250 and 1,000 m, which consisted almost entirely of Photobacterium phosphoreum. The population of P. phosphoreum remained relatively stable in abundance at one station that wa...

  20. Fuel flow distribution in SOFC stacks revealed by impedance spectroscopy

    DEFF Research Database (Denmark)

    Mosbæk, Rasmus Rode; Hjelm, Johan; Barfod, Rasmus


    . An operating stack is subject to compositional gradients in the gaseous reactant streams, and temperature gradients across each cell and across the stack, which complicates detailed analysis. An experimental stack with low ohmic resistance from Topsoe Fuel Cell A/S was characterized using Electrochemical...... Impedance Spectroscopy (EIS). The stack measurement geometry was optimized for EIS by careful selection of the placement of current feeds and voltage probes in order to minimize measurement errors. It was demonstrated that with the improved placement of current feeds and voltage probes it is possible...... to separate the loss contributions in an ohmic and a polarization part and that the low frequency response is useful in detecting mass transfer limitations. This methodology can be used to detect possible minor changes in the supply of gas to the individual cells, which is important when going to high fuel...

  1. Simulation of magnetization and levitation characteristics of HTS tape stacks (United States)

    Anischenko, I. V.; Pokrovskii, S. V.; Mineev, N. A.


    In this work it is presented a computational model of a magnetic levitation system based on stacks of high-temperature second generation superconducting tapes (HTS) GdBa2Cu3O7-x. Calculated magnetic field and the current distributions in the system for different stacks geometries in the zero-field cooling mode are also presented. The magnetization curves of the stacks in the external field of a permanent NdFeB magnet and the levitation force dependence on the gap between the magnet and the HTS tapes stack were obtained. A model of the magnetic system, oriented to levitation application, is given. Results of modeling were compared with the experimental data.

  2. Fast principal component analysis for stacking seismic data (United States)

    Wu, Juan; Bai, Min


    Stacking seismic data plays an indispensable role in many steps of the seismic data processing and imaging workflow. Optimal stacking of seismic data can help mitigate seismic noise and enhance the principal components to a great extent. Traditional average-based seismic stacking methods cannot obtain optimal performance when the ambient noise is extremely strong. We propose a principal component analysis (PCA) algorithm for stacking seismic data without being sensitive to noise level. Considering the computational bottleneck of the classic PCA algorithm in processing massive seismic data, we propose an efficient PCA algorithm to make the proposed method readily applicable for industrial applications. Two numerically designed examples and one real seismic data are used to demonstrate the performance of the presented method.

  3. Static analysis of worst-case stack cache behavior

    DEFF Research Database (Denmark)

    Jordan, Alexander; Brandner, Florian; Schoeberl, Martin


    Utilizing a stack cache in a real-time system can aid predictability by avoiding interference that heap memory traffic causes on the data cache. While loads and stores are guaranteed cache hits, explicit operations are responsible for managing the stack cache. The behavior of these operations can......-graph, the worst-case bounds can be efficiently yet precisely determined. Our evaluation using the MiBench benchmark suite shows that only 37% and 21% of potential stack cache operations actually store to and load from memory, respectively. Analysis times are modest, on average running between 0.46s and 1.30s per...... be analyzed statically. We present algorithms that derive worst-case bounds on the latency-inducing operations of the stack cache. Their results can be used by a static WCET tool. By breaking the analysis down into subproblems that solve intra-procedural data-flow analysis and path searches on the call...

  4. A Stack Cache for Real-Time Systems

    DEFF Research Database (Denmark)

    Schoeberl, Martin; Nielsen, Carsten


    Real-time systems need time-predictable computing platforms to allowfor static analysis of the worst-case execution time. Caches are important for good performance, but data caches arehard to analyze for the worst-case execution time. Stack allocated data has different properties related to local......Real-time systems need time-predictable computing platforms to allowfor static analysis of the worst-case execution time. Caches are important for good performance, but data caches arehard to analyze for the worst-case execution time. Stack allocated data has different properties related...... to locality, lifetime, and static analyzability of access addresses comparedto static or heap allocated data. Therefore, caching of stack allocateddata benefits from having its own cache. In this paper we present a cache architecture optimized for stack allocateddata. This cache is additional to the normal...

  5. DBaaS with OpenStack Trove

    CERN Document Server

    Giardini, Andrea


    The purpose of the project was to evaluate the Trove component for OpenStack, understand if it can be used with the CERN infrastructure and report the benefits and disadvantages of this software. Currently, databases for CERN projects are provided by a DbaaS software developed inside the IT-DB group. This solution works well with the actual infrastructure but it is not easy to maintain. With the migration of the CERN infrastructure to OpenStack the Database group started to evaluate the Trove component. Instead of mantaining an own DbaaS service it can be interesting to migrate everything to OpenStack and replace the actual DbaaS software with Trove. This way both virtual machines and databases will be managed by OpenStack itself.

  6. Stacking dependence of carrier transport properties in multilayered black phosphorous. (United States)

    Sengupta, A; Audiffred, M; Heine, T; Niehaus, T A


    We present the effect of different stacking orders on carrier transport properties of multi-layer black phosphorous. We consider three different stacking orders AAA, ABA and ACA, with increasing number of layers (from 2 to 6 layers). We employ a hierarchical approach in density functional theory (DFT), with structural simulations performed with generalized gradient approximation (GGA) and the bandstructure, carrier effective masses and optical properties evaluated with the meta-generalized gradient approximation (MGGA). The carrier transmission in the various black phosphorous sheets was carried out with the non-equilibrium green's function (NEGF) approach. The results show that ACA stacking has the highest electron and hole transmission probabilities. The results show tunability for a wide range of band-gaps, carrier effective masses and transmission with a great promise for lattice engineering (stacking order and layers) in black phosphorous.

  7. SEE on Different Layers of Stacked-SRAMs

    CERN Document Server

    Gupta, V; Tsiligiannis, G; Rousselet, M; Mohammadzadeh, A; Javanainen, A; Virtanen, A; Puchner, H; Saigné, F; Wrobel, F; Dilillo, L


    This paper presents heavy-ion and proton radiation test results of a 90 nm COTS SRAM with stacked structure. Radiation tests were made using high penetration heavy-ion cocktails at the HIF (Belgium) and at RADEF (Finland) as well as low energy protons at RADEF. The heavy-ion SEU cross-section showed an unusual profile with a peak at the lowest LET (heavy-ion with the highest penetration range). The discrepancy is due to the fact that the SRAM is constituted of two vertically stacked dice. The impact of proton testing on the response of both stacked dice is presented. The results are discussed and the SEU cross-sections of the upper and lower layers are compared. The impact of the stacked structure on the proton SEE rate is investigated.

  8. Admittance Scanning for Whole Column Detection. (United States)

    Stamos, Brian N; Dasgupta, Purnendu K; Ohira, Shin-Ichi


    Whole column detection (WCD) is as old as chromatography itself. WCD requires an ability to interrogate column contents from the outside. Other than the obvious case of optical detection through a transparent column, admittance (often termed contactless conductance) measurements can also sense changes in the column contents (especially ionic content) from the outside without galvanic contact with the solution. We propose here electromechanically scanned admittance imaging and apply this to open tubular (OT) chromatography. The detector scans across the column; the length resolution depends on the scanning velocity and the data acquisition frequency, ultimately limited by the physical step resolution (40 μm in the present setup). Precision equal to this step resolution was observed for locating an interface between two immiscible liquids inside a 21 μm capillary. Mechanically, the maximum scanning speed was 100 mm/s, but at 1 kHz sampling rate and a time constant of 25 ms, the highest practical scan speed (no peak distortion) was 28 mm/s. At scanning speeds of 0, 4, and 28 mm/s, the S/N for 180 pL (zone length of 1.9 mm in a 11 μm i.d. column) of 500 μM KCl injected into water was 6450, 3850, and 1500, respectively. To facilitate constant and reproducible contact with the column regardless of minor variations in outer diameter, a double quadrupole electrode system was developed. Columns of significant length (>1 m) can be readily scanned. We demonstrate its applicability with both OT and commercial packed columns and explore uniformity of retention along a column, increasing S/N by stopped-flow repeat scans, etc. as unique applications.

  9. Fingerprint development for Ginkgo biloba extracts by pressurized capillary electrochromatography: comparison of column types. (United States)

    Wang, Jiajing; Tanret, Indiana; Mangelings, Debby; Fan, Guorong; Wu, Yutian; Vander Heyden, Yvan


    A pressurized capillary electrochromatographic (pCEC) fingerprint of Ginkgo biloba leaf extract was developed on three different types of capillary columns. A commercial column packed with 3-microm particles and an in-house column packed with 5-microm particles were investigated for their performance. Additionally, a monolithic column was included in the fingerprint study as a potential alternative to the conventional packed columns. The effects of experimental parameters, such as the composition of the mobile phase, the concentration and pH of the buffer, and the applied voltage, were studied. Binary mobile phases consisting of acetonitrile and a 5 mM sodium dihydrogen phosphate electrolyte at pH 2.8 were used in gradient elution mode with an applied voltage of 5 kV. Under optimal gradient conditions, at least 45 peaks were observed within 60 min on the commercial packed column, whereas only about 20 peaks were separated on the methacrylate-based monolithic and the in-house packed columns. The commercial column thus clearly outperforms the two other. However, the properties of the monolithic stationary phase still might be adapted (i.e., by changing the polymerization-mixture composition, the porosity, and thus the selectivity of the phase might be changed), which could lead to an improved efficiency.

  10. Neuronal connections of eye-dominance columns in the cat cerebral cortex after monocular deprivation. (United States)

    Alekseenko, S V; Toporova, S N; Shkorbatova, P Yu


    Plastic changes in intrahemisphere neuronal connections of the eye-dominance columns of cortical fields 17 and 18 were studied in monocularly deprived cats. The methodology consisted of microintophoretic administration of horseradish peroxidase into cortical columns and three-dimensional reconstruction of the areas of retrograde labeled cells. The eye dominance of columns was established, as were their coordinates in the projection of the visual field. In field 17, the horizontal connections of columns receiving inputs from the non-deprived eye via the crossed-over visual tracts were longer than the connections of the "non-crossed" columns of this eye and were longer than in normal conditions; the connections of the columns of the deprived eye were significantly reduced. Changes in the spatial organization of horizontal connections in field 17 were seen for the columns of the non-deprived eye (areas of labeled cells were rounder and the density of labeled cells in these areas were non-uniform). The longest horizontal connections in deprived cats were no longer than the lengths of these connections in cats with strabismus. It is suggested that the axon length of cells giving rise to the horizontal connections of cortical columns has a limit which is independent of visual stimulation during the critical period of development of the visual system.

  11. Mathematical model and simulation of the hydrodynamic of air-pulsed sieve plate columns

    International Nuclear Information System (INIS)

    Hannappel, J.; Pfeifer, W.; Rathjen, E.


    In this work the dynamic flow events in an air pulsed sieve plate column are described by a simulation model. The model consists of a system of differential equations. The pressure built up by the pulsed air is brought to equilibrium with the pressure losses of the oscillating liquid column in the pulsation tube and in the column. In case of definition of the a) column geometry, b) integral holdup of the column, c) density of the participating phases, d) control times of the pulsed air valves, e) pulse repetition frequency and pulsed air reservoir pressure the height of oscillation and hence the intensity of pulsation are calculated. It is shown by a concrete example that 1) the oscillation of the liquid column in the pulsation tube and in the column is sinusoidal in all cases; 2) generation of a defined pulsation is restricted to the range between 0.3 and 3 Hz; 3) the amount of air needed for pulsation depends on the geometry of the column and in the intensity of pulsation. It can be optimized by appropriate selection of the diameter of the pulsation tube. (orig.) [de

  12. Modeling of a Stacked Power Module for Parasitic Inductance Extraction (United States)


    ARL-TR-8138 ● SEP 2017 US Army Research Laboratory Modeling of a Stacked Power Module for Parasitic Inductance Extraction by...not return it to the originator. ARL-TR-8138 ● SEP 2017 US Army Research Laboratory Modeling of a Stacked Power Module for...aware that notwithstanding any other provision of law , no person shall be subject to any penalty for failing to comply with a collection of information if

  13. National Spherical Torus Experiment (NSTX) Center Stack Upgrade

    International Nuclear Information System (INIS)

    Neumeyer, C.; Avasarala, S.; Chrzanowski, J.; Dudek, L.; Fan, H.; Hatcher, H.; Heitzenroeder, P.; Menard, J.; Ono, M.; Ramakrishnan, S.; Titus, P.; Woolley, R.; Zhan, H.


    The purpose of the NSTX Center Stack Upgrade project is to expand the NSTX operational space and thereby the physics basis for next-step ST facilities. The plasma aspect ratio (ratio of plasma major to minor radius) of the upgrade is increased to 1.5 from the original value of 1.26, which increases the cross sectional area of the center stack by a factor of ∼ 3 and makes possible higher levels of performance and pulse duration.

  14. A new method for beam stacking in storage rings

    Energy Technology Data Exchange (ETDEWEB)

    Bhat, C.M.; /Fermilab


    Recently, I developed a new beam stacking scheme for synchrotron storage rings called 'longitudinal phase-space coating' (LPSC). This scheme has been convincingly validated by multi-particle beam dynamics simulations and has been demonstrated with beam experiments at the Fermilab Recycler. Here, I present the results from both simulations and experiments. The beam stacking scheme presented here is the first of its kind.

  15. Stacking faults and phase transformations in silicon nitride (United States)

    Milhet, X.; Demenet, J.-L.; Rabier, J.


    From observations of extended dislocation nodes in β silicon nitride, possible stacking fault structures in the basal plane of this compound have been investigated. It has been found that stacking fault structure is locally analogous to α silicon nitride. A phase transformation α to β or β to α can also be achieved by cooperative shear of partial dislocations with 1/3<~ngle1bar{1}00rangle Burgers vectors.

  16. LOFT diesel generator ''A'' exhaust stack seismic analysis

    International Nuclear Information System (INIS)

    Blandford, R.K.


    A stress analysis of the LOFT Diesel Generator ''A'' Exhaust Stack was performed to determine its reaction to Safe-Shutdown Earthquake loads. The exhaust stack silencer and supporting foundation was found to be inadequate for the postulated seismic accelerations. Lateral support is required to prevent overturning of the silencer pedestal and reinforcement of the 4'' x 0.5'' silencer base straps is necessary. Basic requirements for this additional support are discussed

  17. Field-induced stacking transition of biofunctionalized trilayer graphene

    Energy Technology Data Exchange (ETDEWEB)

    Masato Nakano, C. [Flintridge Preparatory School, La Canada, California 91011 (United States); Sajib, Md Symon Jahan; Samieegohar, Mohammadreza; Wei, Tao [Dan F. Smith Department of Chemical Engineering, Lamar University, Beaumont, Texas 77710 (United States)


    Trilayer graphene (TLG) is attracting a lot of attention as their stacking structures (i.e., rhombohedral vs. Bernal) drastically affect electronic and optical properties. Based on full-atom molecular dynamics simulations, we here predict electric field-induced rhombohedral-to-Bernal transition of TLG tethered with proteins. Furthermore, our simulations show that protein's electrophoretic mobility and diffusivity are enhanced on TLG surface. This phenomenon of controllable TLG stacking transition will contribute to various applications including biosensing.

  18. Results of the eruptive column model inter-comparison study (United States)

    Costa, Antonio; Suzuki, Yujiro; Cerminara, M.; Devenish, Ben J.; Esposti Ongaro, T.; Herzog, Michael; Van Eaton, Alexa; Denby, L.C.; Bursik, Marcus; de' Michieli Vitturi, Mattia; Engwell, S.; Neri, Augusto; Barsotti, Sara; Folch, Arnau; Macedonio, Giovanni; Girault, F.; Carazzo, G.; Tait, S.; Kaminski, E.; Mastin, Larry G.; Woodhouse, Mark J.; Phillips, Jeremy C.; Hogg, Andrew J.; Degruyter, Wim; Bonadonna, Costanza


    This study compares and evaluates one-dimensional (1D) and three-dimensional (3D) numerical models of volcanic eruption columns in a set of different inter-comparison exercises. The exercises were designed as a blind test in which a set of common input parameters was given for two reference eruptions, representing a strong and a weak eruption column under different meteorological conditions. Comparing the results of the different models allows us to evaluate their capabilities and target areas for future improvement. Despite their different formulations, the 1D and 3D models provide reasonably consistent predictions of some of the key global descriptors of the volcanic plumes. Variability in plume height, estimated from the standard deviation of model predictions, is within ~ 20% for the weak plume and ~ 10% for the strong plume. Predictions of neutral buoyancy level are also in reasonably good agreement among the different models, with a standard deviation ranging from 9 to 19% (the latter for the weak plume in a windy atmosphere). Overall, these discrepancies are in the range of observational uncertainty of column height. However, there are important differences amongst models in terms of local properties along the plume axis, particularly for the strong plume. Our analysis suggests that the simplified treatment of entrainment in 1D models is adequate to resolve the general behaviour of the weak plume. However, it is inadequate to capture complex features of the strong plume, such as large vortices, partial column collapse, or gravitational fountaining that strongly enhance entrainment in the lower atmosphere. We conclude that there is a need to more accurately quantify entrainment rates, improve the representation of plume radius, and incorporate the effects of column instability in future versions of 1D volcanic plume models.

  19. Time-consistent and market-consistent evaluations

    NARCIS (Netherlands)

    Pelsser, A.; Stadje, M.A.


    We consider evaluation methods for payoffs with an inherent financial risk as encountered for instance for portfolios held by pension funds and insurance companies. Pricing such payoffs in a way consistent to market prices typically involves combining actuarial techniques with methods from

  20. Standoff Stack Emissions Monitoring Using Short Range Lidar (United States)

    Gravel, Jean-Francois Y.; Babin, Francois; Allard, Martin


    There are well documented methods for stack emissions monitoring. These are all based on stack sampling through sampling ports in well defined conditions. Once sampled, the molecules are quantified in instruments that often use optical techniques. Unfortunately sampling ports are not found on all stacks/ducts or the use of the sampling ports cannot be planned efficiently because of operational constraints or the emissions monitoring equipment cannot be driven to a remote stack/duct. Emissions monitoring using many of the same optical techniques, but at a standoff distance, through the atmosphere, using short range high spatial resolution lidar techniques was thus attempted. Standoff absorption and Raman will be discussed and results from a field campaign will be presented along with short descriptions of the apparatus. In the first phase of these tests, the molecules that were targeted were NO and O2. Spatially resolved optical measurements allow for standoff identification and quantification of molecules, much like the standardized methods, except for the fact that it is not done in the stack, but in the plume formed by the emissions from the stack. The pros and cons will also be discussed, and in particular the problem of mass emission estimates that require the knowledge of the flow rate and the distribution of molecular concentration in the plane of measurement.

  1. Standoff Stack Emissions Monitoring Using Short Range Lidar

    Directory of Open Access Journals (Sweden)

    Gravel Jean-Francois Y.


    Full Text Available There are well documented methods for stack emissions monitoring. These are all based on stack sampling through sampling ports in well defined conditions. Once sampled, the molecules are quantified in instruments that often use optical techniques. Unfortunately sampling ports are not found on all stacks/ducts or the use of the sampling ports cannot be planned efficiently because of operational constraints or the emissions monitoring equipment cannot be driven to a remote stack/duct. Emissions monitoring using many of the same optical techniques, but at a standoff distance, through the atmosphere, using short range high spatial resolution lidar techniques was thus attempted. Standoff absorption and Raman will be discussed and results from a field campaign will be presented along with short descriptions of the apparatus. In the first phase of these tests, the molecules that were targeted were NO and O2. Spatially resolved optical measurements allow for standoff identification and quantification of molecules, much like the standardized methods, except for the fact that it is not done in the stack, but in the plume formed by the emissions from the stack. The pros and cons will also be discussed, and in particular the problem of mass emission estimates that require the knowledge of the flow rate and the distribution of molecular concentration in the plane of measurement.

  2. Market-consistent actuarial valuation

    CERN Document Server

    Wüthrich, Mario V


    This is the third edition of this well-received textbook, presenting powerful methods for measuring insurance liabilities and assets in a consistent way, with detailed mathematical frameworks that lead to market-consistent values for liabilities. Topics covered are stochastic discounting with deflators, valuation portfolio in life and non-life insurance, probability distortions, asset and liability management, financial risks, insurance technical risks, and solvency. Including updates on recent developments and regulatory changes under Solvency II, this new edition of Market-Consistent Actuarial Valuation also elaborates on different risk measures, providing a revised definition of solvency based on industry practice, and presents an adapted valuation framework which takes a dynamic view of non-life insurance reserving risk.

  3. Consistent force fields for saccharides

    DEFF Research Database (Denmark)

    Rasmussen, Kjeld


    Consistent force fields for carbohydrates were hitherto developed by extensive optimization ofpotential energy function parameters on experimental data and on ab initio results. A wide range of experimental data is used: internal structures obtained from gas phase electron diffraction and from x......-anomeric effects are accounted for without addition of specific terms. The work is done in the framework of the Consistent Force Field which originatedin Israel and was further developed in Denmark. The actual methods and strategies employed havebeen described previously. Extensive testing of the force field...

  4. Fracture Analysis of Debonded Sandwich Columns Under Axial Compression

    DEFF Research Database (Denmark)

    May, A.; Avilés, F.; Berggreen, Christian

    A sandwich structure consists of two strong and stiff face sheets bonded to a weak low density core. The large separation between the face sheets provides increased bending rigidity and strength at low weight cost. Thus, sandwich structures frequently present better mechanical properties than...... monolithic structures of the same weight. The vast range of applications of such materials includes wind turbines, marine, and aerospace industries. In this work, geometrically nonlinear finite element analysis is conducted to investigate the fracture parameters and debond propagation of sandwich columns...... containing a face-to-core debond subjected to axial compression. Bidimensional finite element models of sandwich columns containing different size debonds centered at one face/core interface were developed and used in conjunction with linear elastic fracture mechanics to predict the stress intensity factors...

  5. Mt. Pinatubo SO2 Column Measurements From Mauna Loa (United States)

    Goldman, A.; Murcray, F. J.; Rinsland, C. P.; Blatherwick, R. D.; David, S. J.; Murcray, F. H.; Murcray, D. G.


    Absorption features of the nu(sub 1) band of SO2 have been identified in high resolution infrared solar absorption spectra recorded from Mauna Loa, Hawaii, on July 9 and 12, 1991, shortly after the arrival of the first eruption plume from the Mt. Pinatubo volcano in the Phillipines. A total SO2 vertical column amount of (5.1 +/- 0.5) x 10(exp 16) molecules/sq cm on July 9 has been retrieved based on nonlinear least- squares spectral fittings of 9 selected SO2 absorption features with an updated set of SO2 spectral parameters. A SO2 total column upper limit of 0.9 x 10(esp 16) molecules/sq cm deduced from measurements on September 20-24, 1991, is consistent with the dispersion of the SO2 cloud and the rapid conversion of the SO2 vapor into volcanic aerosol particles.

  6. CFD studies of mass transfer performance in pulsed column

    International Nuclear Information System (INIS)

    Hou Hongguo; Ma Haiyan; Zhu Rongkai; Jiao Caishan


    A tracer injection technique was used to study the mass transfer characteristics of aqueous phase in the Φ 38 mm pulsed sieve extraction column. A computational fluid dynamics (CFD) model has been developed to simulation the mass transfer process of the tracer. The residence time distribution of the tracer which get from CFD simulation were used to fitting the aqueous phase axial dispersion coefficient. The experiment results were in consistence with the simulation results; The simulation results show that the concentration of tracer change with pulsed velocity; The axial dispersion co efficient fitting by CFD model was Similar with published data. The presented CFD predictions and validation with experimental data will provide a possible ways to eliminate experiments and will contribute to better understanding of the hydrodynamics in extraction columns. (authors)

  7. Finite length thermal equilibria of a pure electron plasma column

    International Nuclear Information System (INIS)

    Prasad, S.A.; O'Neil, T.M.


    The electrons of a pure electron plasma may be in thermal equilibrium with each other and still be confined by static magnetic and electric fields. Since the electrons make a significant contribution to the electric field, only certain density profiles are consistent with Poisson's equation. The class of such distributions for a finite length cylindrical column is investigated. In the limit where the Debye length is small compared with the dimensions of the column, the density is essentially constant out to some surface of revolution and then falls off abruptly. The falloff in density is a universal function when measured along the local normal to the surface of revolution and scaled in terms of the Debye length. The solution for the shape of the surface of revolution is simplified by passage to the limit of zero Debye length

  8. Column Experiments to Interpret Weathering in Columbia Hills (United States)

    Hausrath, E. M.; Morris, R.V.; Ming, D.W.; Golden, D.C.; Galindo, C.; Sutter, B.


    Phosphate mobility has been postulated as an indicator of early aqueous activity on Mars. In addition, rock surfaces analyzed by the Mars Exploration Rover Spirit are consistent with the loss of a phosphate- containing mineral To interpret phosphate alteration behavior on Mars, we performed column dissolution experiments leaching the primary phases Durango fluorapatite, San Carlos olivine, and basalt glass (Stapafjell Volcano, courtesy of S. Gislason, University of Iceland) [3,4]) with acidic solutions. These phases were chosen to represent quickly dissolving phases likely present in Columbia Hills. Column dissolution experiments are closer to natural dissolution conditions than batch experiments, although they can be difficult to interpret. Acidic solutions were used because the leached layers on the surfaces of these rocks have been interpreted as resulting from acid solutions [5].

  9. Field Applications of Gamma Column Scanning Technology

    International Nuclear Information System (INIS)

    Aquino, Denis D.; Mallilin, Janice P.; Nuñez, Ivy Angelica A.; Bulos, Adelina DM.


    The Isotope Techniques Section (ITS) under the Nuclear Service Division (NSD) of the Philippine Nuclear Research Institute (PNRI) conducts services, research and development on radioisotope and sealed source application in the industry. This aims to benefit the manufacturing industries such as petroleum, petrochemical, chemical, energy, waste, column treatment plant, etc. through on line inspection and troubleshooting of a process vessel, column or pipe that could optimize the process operation and increase production efficiency. One of the most common sealed source techniques for industrial applications is the gamma column scanning technology. Gamma column scanning technology is an established technique for inspection, analysis and diagnosis of industrial columns for process optimization, solving operational malfunctions and management of resources. It is a convenient non-intrusive, cost effective and cost-efficient technique to examine inner details of an industrial process vessel such as a distillation column while it is in operation. The Philippine Nuclear Research Institute (PNRI) recognize the importance and benefits of this technology and has implemented activities to make gamma column scanning locally available to benefit the Philippine industries. Continuous effort for capacity building is being pursued thru the implementation of in-house and on-the-job training abroad and upgrading of equipment. (author)

  10. Collapse of tall granular columns in fluid

    Directory of Open Access Journals (Sweden)

    Kumar Krishna


    Full Text Available Avalanches, landslides, and debris flows are geophysical hazards, which involve rapid mass movement of granular solids, water, and air as a multi-phase system. In order to describe the mechanism of immersed granular flows, it is important to consider both the dynamics of the solid phase and the role of the ambient fluid. In the present study, the collapse of a granular column in fluid is studied using 2D LBM - DEM. The flow kinematics are compared with the dry and buoyant granular collapse to understand the influence of hydrodynamic forces and lubrication on the run-out. In the case of tall columns, the amount of material destabilised above the failure plane is larger than that of short columns. Therefore, the surface area of the mobilised mass that interacts with the surrounding fluid in tall columns is significantly higher than the short columns. This increase in the area of soil - fluid interaction results in an increase in the formation of turbulent vortices thereby altering the deposit morphology. It is observed that the vortices result in the formation of heaps that significantly affects the distribution of mass in the flow. In order to understand the behaviour of tall columns, the run-out behaviour of a dense granular column with an initial aspect ratio of 6 is studied. The collapse behaviour is analysed for different slope angles: 0°, 2.5°, 5° and 7.5°.

  11. Collapse of tall granular columns in fluid (United States)

    Kumar, Krishna; Soga, Kenichi; Delenne, Jean-Yves


    Avalanches, landslides, and debris flows are geophysical hazards, which involve rapid mass movement of granular solids, water, and air as a multi-phase system. In order to describe the mechanism of immersed granular flows, it is important to consider both the dynamics of the solid phase and the role of the ambient fluid. In the present study, the collapse of a granular column in fluid is studied using 2D LBM - DEM. The flow kinematics are compared with the dry and buoyant granular collapse to understand the influence of hydrodynamic forces and lubrication on the run-out. In the case of tall columns, the amount of material destabilised above the failure plane is larger than that of short columns. Therefore, the surface area of the mobilised mass that interacts with the surrounding fluid in tall columns is significantly higher than the short columns. This increase in the area of soil - fluid interaction results in an increase in the formation of turbulent vortices thereby altering the deposit morphology. It is observed that the vortices result in the formation of heaps that significantly affects the distribution of mass in the flow. In order to understand the behaviour of tall columns, the run-out behaviour of a dense granular column with an initial aspect ratio of 6 is studied. The collapse behaviour is analysed for different slope angles: 0°, 2.5°, 5° and 7.5°.

  12. Recognition of depositional sequences and stacking patterns, Late Devonian (Frasnian) carbonate platforms, Alberta basin

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, J.H.; Reeckmann, S.A.; Sarg, J.F.; Greenlee, S.M.


    Six depositional sequences bounded by regional unconformities or their correlative equivalents (sequence boundaries) have been recognized in Late Devonian (Frasnian) carbonate platforms in the Alberta basin. These sequences consist of a predictable vertical succession of smaller scale shoaling-upward cycles (parasequences). Parasequences are arranged in retrogradational, aggradational, and progradational stacking patterns that can be modeled as a sediment response to relative changes in sea level. Sequence boundaries are recognized by onlap onto underlying shelf or shelf margin strata. This onlap includes shelf margin wedges and deep marine onlap. In outcrop sections shelf margin wedges exhibit an abrupt juxtaposition of shallow water facies over deeper water deposits with no gradational facies changes at the boundaries. High on the platform, subaerial exposure fabrics may be present. The shelf margin wedges are interpreted to have formed during lowstands in sea level and typically exhibit an aggradational stacking pattern. On the platform, two types of sequences are recognized. A type 1 cycle occurs where the sequence boundary is overlain by a flooding surface and subsequent parasequences exhibit retrogradational stacking. In a type 2 cycle the sequence boundary is overlain by an aggradational package of shallow water parasequences, followed by a retrogradational package. These two types of sequences can be modeled using a sinusoidal eustatic sea level curve superimposed on thermo-tectonic subsidence.

  13. Bottom-up Fabrication of Multilayer Stacks of 3D Photonic Crystals from Titanium Dioxide. (United States)

    Kubrin, Roman; Pasquarelli, Robert M; Waleczek, Martin; Lee, Hooi Sing; Zierold, Robert; do Rosário, Jefferson J; Dyachenko, Pavel N; Montero Moreno, Josep M; Petrov, Alexander Yu; Janssen, Rolf; Eich, Manfred; Nielsch, Kornelius; Schneider, Gerold A


    A strategy for stacking multiple ceramic 3D photonic crystals is developed. Periodically structured porous films are produced by vertical convective self-assembly of polystyrene (PS) microspheres. After infiltration of the opaline templates by atomic layer deposition (ALD) of titania and thermal decomposition of the polystyrene matrix, a ceramic 3D photonic crystal is formed. Further layers with different sizes of pores are deposited subsequently by repetition of the process. The influence of process parameters on morphology and photonic properties of double and triple stacks is systematically studied. Prolonged contact of amorphous titania films with warm water during self-assembly of the successive templates is found to result in exaggerated roughness of the surfaces re-exposed to ALD. Random scattering on rough internal surfaces disrupts ballistic transport of incident photons into deeper layers of the multistacks. Substantially smoother interfaces are obtained by calcination of the structure after each infiltration, which converts amorphous titania into the crystalline anatase before resuming the ALD infiltration. High quality triple stacks consisting of anatase inverse opals with different pore sizes are demonstrated for the first time. The elaborated fabrication method shows promise for various applications demanding broadband dielectric reflectors or titania photonic crystals with a long mean free path of photons.

  14. A miniaturized human-motion energy harvester using flux-guided magnet stacks

    International Nuclear Information System (INIS)

    Halim, M A; Park, J Y


    We present a miniaturized electromagnetic energy harvester (EMEH) using two flux-guided magnet stacks to harvest energy from human-generated vibration such as handshaking. Each flux-guided magnet stack increases (40%) the magnetic flux density by guiding the flux lines through a soft magnetic material. The EMEH has been designed to up-convert the applied human-motion vibration to a high-frequency oscillation by mechanical impact of a spring-less structure. The high-frequency oscillator consists of the analyzed 2-magnet stack and a customized helical compression spring. A standard AAA battery sized prototype (3.9 cm 3 ) can generate maximum 203 μW average power from human hand-shaking vibration. It has a maximum average power density of 52 μWcm -3 which is significantly higher than the current state-of-the-art devices. A 6-stage multiplier and rectifier circuit interfaces the harvester with a wearable electronic load (wrist watch) to demonstrate its capability of powering small- scale electronic systems from human-generated vibration. (paper)

  15. Consistent deformations of dual formulations of linearized gravity: A no-go result

    International Nuclear Information System (INIS)

    Bekaert, Xavier; Boulanger, Nicolas; Henneaux, Marc


    The consistent, local, smooth deformations of the dual formulation of linearized gravity involving a tensor field in the exotic representation of the Lorentz group with Young symmetry type (D-3,1) (one column of length D-3 and one column of length 1) are systematically investigated. The rigidity of the Abelian gauge algebra is first established. We next prove a no-go theorem for interactions involving at most two derivatives of the fields

  16. Novel process integration for biodiesel blend in membrane reactive divided wall (MRDW) column


    Sakhre Vandana; Jain Sanjeev; Sapkal Vilas S.; Agarwal Dev P.


    The paper proposes a novel process integration for biodiesel blend in the Membrane assisted Reactive Divided Wall Distillation (MRDW) column. Biodiesel is a green fuel and grade of biodiesel blend is B20 (%) which consist of 20% biodiesel and rest 80% commercial diesel. Instead of commercial diesel, Tertiary Amyl Ethyl Ether (TAEE) was used as an environment friendly fuel for blending biodiesel. Biodiesel and TAEE were synthesized in a pilot scale reactive distillation column. Dual reactive d...

  17. Effect of mobilities and electric field on the stability of magnetized positive column

    International Nuclear Information System (INIS)

    Dogra, V.K.; Uberoi, M.S.


    The effect of ratio of the mobilities of electrons and ions and non-dimensional electric field, on the stability of magnetized positive column for all unstable modes is studied in a self-consistent formulation for the perturbations of plasma density and electric potential. The minimum non-dimensional electric field at which magnetized positive column becomes unstable for different ratios of the mobilities of electrons and ions is also investigated. (author)

  18. Teaching Consistency of UML Specifications

    NARCIS (Netherlands)

    Sikkel, Nicolaas; Daneva, Maia


    Consider the situation that you have a data model, a functional model and a process model of a system, perhaps made by different analysts at different times. Are these models consistent with each other? A relevant question in practice – and therefore we think it should also be addressed in our

  19. Dynamically consistent oil import tariffs

    International Nuclear Information System (INIS)

    Karp, L.; Newbery, D.M.


    The standard theory of optimal tariffs considers tariffs on perishable goods produced abroad under static conditions, in which tariffs affect prices only in that period. Oil and other exhaustable resources do not fit this model, for current tariffs affect the amount of oil imported, which will affect the remaining stock and hence its future price. The problem of choosing a dynamically consistent oil import tariff when suppliers are competitive but importers have market power is considered. The open-loop Nash tariff is solved for the standard competitive case in which the oil price is arbitraged, and it was found that the resulting tariff rises at the rate of interest. This tariff was found to have an equilibrium that in general is dynamically inconsistent. Nevertheless, it is shown that necessary and sufficient conditions exist under which the tariff satisfies the weaker condition of time consistency. A dynamically consistent tariff is obtained by assuming that all agents condition their current decisions on the remaining stock of the resource, in contrast to open-loop strategies. For the natural case in which all agents choose their actions simultaneously in each period, the dynamically consistent tariff was characterized, and found to differ markedly from the time-inconsistent open-loop tariff. It was shown that if importers do not have overwhelming market power, then the time path of the world price is insensitive to the ability to commit, as is the level of wealth achieved by the importer. 26 refs., 4 figs

  20. Time-consistent actuarial valuations

    NARCIS (Netherlands)

    Pelsser, A.A.J.; Salahnejhad Ghalehjooghi, A.


    Time-consistent valuations (i.e. pricing operators) can be created by backward iteration of one-period valuations. In this paper we investigate the continuous-time limits of well-known actuarial premium principles when such backward iteration procedures are applied. This method is applied to an

  1. Dynamic effects of diabatization in distillation columns

    DEFF Research Database (Denmark)

    Bisgaard, Thomas; Huusom, Jakob Kjøbsted; Abildskov, Jens


    The dynamic effects of diabatization in distillation columns are investigated in simulation emphasizing the heat-integrated distillation column (HIDiC). A generic, dynamic, first-principle model has been formulated, which is flexible enough to describe various diabatic distillation configurations....... Dynamic Relative Gain Array and Singular Value Analysis have been applied in a comparative study of a conventional distillation column and a HIDiC. The study showed increased input-output coupling due to diabatization. Feasible SISO control structures for the HIDiC were also found and control...

  2. Dynamic Effects of Diabatization in Distillation Columns

    DEFF Research Database (Denmark)

    Bisgaard, Thomas; Huusom, Jakob Kjøbsted; Abildskov, Jens


    The dynamic eects of diabatization in distillation columns are investigated in simulation with primary focus on the heat-integrated distillation column (HIDiC). A generic, dynamic, rst-principle model has been formulated, which is exible to describe various diabatic distillation congurations....... Dynamic Relative Gain Array and Singular Value Analysis have been applied in a comparative study of a conventional distillation column and a HIDiC. The study showed increased input-output coupling due to diabatization. Feasible SISO control structures for the HIDiC were also found. Control...

  3. Study on optimization of YBCO thin film stack for compact NMR magnets

    International Nuclear Information System (INIS)

    Kim, S.B.; Kimoto, T.; Hahn, S.; Iwasa, Y.; Voccio, J.; Tomita, M.


    Highlights: ► Stacking methods for compact NMR magnet using YBCO thin films were tested. ► The stacking angles are 0°, 22.5° and 90° against the rolling direction. ► The best spatial field homogeneity was obtained in rotation angle of 22.5°. ► The maximum trapped magnetic fields of 0.4 T was obtained at 77.4 K. ► The maximum trapped magnetic fields of 0.95 T was obtained at 21 K. -- Abstract: A compact high temperature superconducting (HTS) magnet, which consists of a stack of 500 HTS thin film annuli, was constructed and tested. Each thin film annulus, manufactured by the AMSC using the Rolling Assisted Bi-axially Textured Substrate (RABiTS) method, has a square cross-section of 40 mm × 40 mm with a thickness of 80 m. It has a 25-mm center hole created by machining. This paper reports a study on the anisotropic J c issue due to the rolling procedure of the Ni substrate direction and its impact on field homogeneity. Also, three different stacking methods with rotation angles of 22.5°, 90°, and 0° against the rolling direction have been tested to study their impacts on strength, spatial homogeneity, and temporal stability of trapped fields. Finally, the 500-annulus magnet was tested at 21 K under a cryogen-free environment using a GM cryocooler. The spatial field homogeneity and temporal stability were measured at 21 K and compared with those obtained in a bath of liquid nitrogen at 77 K

  4. Calibration and GEANT4 Simulations of the Phase II Proton Compute Tomography (pCT) Range Stack Detector

    Energy Technology Data Exchange (ETDEWEB)

    Uzunyan, S. A. [Northern Illinois Univ., DeKalb, IL (United States); Blazey, G. [Northern Illinois Univ., DeKalb, IL (United States); Boi, S. [Northern Illinois Univ., DeKalb, IL (United States); Coutrakon, G. [Northern Illinois Univ., DeKalb, IL (United States); Dyshkant, A. [Northern Illinois Univ., DeKalb, IL (United States); Francis, K. [Northern Illinois Univ., DeKalb, IL (United States); Hedin, D. [Northern Illinois Univ., DeKalb, IL (United States); Johnson, E. [Northern Illinois Univ., DeKalb, IL (United States); Kalnins, J. [Northern Illinois Univ., DeKalb, IL (United States); Zutshi, V. [Northern Illinois Univ., DeKalb, IL (United States); Ford, R. [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Rauch, J. E. [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Rubinov, P. [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Sellberg, G. [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Wilson, P. [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Naimuddin, M. [Univ. of Delhi, New Delhi (India)


    Northern Illinois University in collaboration with Fermi National Accelerator Laboratory (FNAL) and Delhi University has been designing and building a proton CT scanner for applications in proton treatment planning. The Phase II proton CT scanner consists of eight planes of tracking detectors with two X and two Y coordinate measurements both before and after the patient. In addition, a range stack detector consisting of a stack of thin scintillator tiles, arranged in twelve eight-tile frames, is used to determine the water equivalent path length (WEPL) of each track through the patient. The X-Y coordinates and WEPL are required input for image reconstruction software to find the relative (proton) stopping powers (RSP) value of each voxel in the patient and generate a corresponding 3D image. In this Note we describe tests conducted in 2015 at the proton beam at the Central DuPage Hospital in Warrenville, IL, focusing on the range stack calibration procedure and comparisons with the GEANT~4 range stack simulation.

  5. ADAM28 localizes to HLA-G+ trophoblasts and promotes column cell outgrowth. (United States)

    De Luca, L C; Le, H T; Mara, D L; Beristain, A G


    Trophoblast progenitor cell differentiation towards the extravillous trophoblast (EVT) lineage initiates within proximal regions of anchoring columns of first trimester placental villi. While molecular processes controlling the initial stages of progenitor cell differentiation along the EVT pathway have been described, much remains unknown about factors important in distal column cell differentiation into invasive EVTs. ADAMs are proteases that regulate growth factor signaling, cell-matrix adhesion, and matrix proteolysis, and thus impact many processes relevant in placentation. Global gene expression studies identified the ADAM subtype, ADAM28, to be highly expressed in EVT-like trophoblasts, suggesting that it may play a role in EVT function. This study aims to test the functional importance of ADAM28 in column cell outgrowth and maintenance. ADAM28 mRNA levels and protein localization were determined by qPCR and immunofluorescence microscopy analyses in purified placental villi cell populations and tissues. ADAM28 function in trophoblast column outgrowth was examined using ADAM28-targetting siRNAs in Matrigel-imbedded placental explant cultures. Within placental villi, ADAM28 mRNA levels were highest in HLA-G + column trophoblasts, and consistent with this, ADAM28 was preferentially localized to HLA-G + trophoblasts within distal anchoring columns and decidual tissue. siRNA-directed loss of ADAM28 impaired trophoblast column outgrowth and resulted in increased apoptosis in matrix-invading trophoblasts. Our findings suggest that ADAM28 promotes column outgrowth by providing survival cues within anchoring column cells. This study also provides insight into a possible role for ADAM28 in driving differentiation of column trophoblasts into invasive HLA-G + EVT subsets. Copyright © 2017 Elsevier Ltd. All rights reserved.

  6. Self-consistent radial sheath

    International Nuclear Information System (INIS)

    Hazeltine, R.D.


    The boundary layer arising in the radial vicinity of a tokamak limiter is examined, with special reference to the TEXT tokamak. It is shown that sheath structure depends upon the self-consistent effects of ion guiding-center orbit modification, as well as the radial variation of E /times/ B-induced toroidal rotation. Reasonable agreement with experiment is obtained from an idealized model which, however simplified, preserves such self-consistent effects. It is argued that the radial sheath, which occurs whenever confining magnetic field-lines lie in the plasma boundary surface, is an object of some intrinsic interest. It differs from the more familiar axial sheath because magnetized charges respond very differently to parallel and perpendicular electric fields. 11 refs., 1 fig

  7. Deep Feature Consistent Variational Autoencoder


    Hou, Xianxu; Shen, Linlin; Sun, Ke; Qiu, Guoping


    We present a novel method for constructing Variational Autoencoder (VAE). Instead of using pixel-by-pixel loss, we enforce deep feature consistency between the input and the output of a VAE, which ensures the VAE's output to preserve the spatial correlation characteristics of the input, thus leading the output to have a more natural visual appearance and better perceptual quality. Based on recent deep learning works such as style transfer, we employ a pre-trained deep convolutional neural net...

  8. Consistent interpretations of quantum mechanics

    International Nuclear Information System (INIS)

    Omnes, R.


    Within the last decade, significant progress has been made towards a consistent and complete reformulation of the Copenhagen interpretation (an interpretation consisting in a formulation of the experimental aspects of physics in terms of the basic formalism; it is consistent if free from internal contradiction and complete if it provides precise predictions for all experiments). The main steps involved decoherence (the transition from linear superpositions of macroscopic states to a mixing), Griffiths histories describing the evolution of quantum properties, a convenient logical structure for dealing with histories, and also some progress in semiclassical physics, which was made possible by new methods. The main outcome is a theory of phenomena, viz., the classically meaningful properties of a macroscopic system. It shows in particular how and when determinism is valid. This theory can be used to give a deductive form to measurement theory, which now covers some cases that were initially devised as counterexamples against the Copenhagen interpretation. These theories are described, together with their applications to some key experiments and some of their consequences concerning epistemology

  9. Unbonded Prestressed Columns for Earthquake Resistance (United States)


    Modern structures are able to survive significant shaking caused by earthquakes. By implementing unbonded post-tensioned tendons in bridge columns, the damage caused by an earthquake can be significantly lower than that of a standard reinforced concr...

  10. Tests on duralumin columns for aircraft construction (United States)

    Lee, John G


    The following paper is based on the results of tests, upon duralumin columns, contained in two theses presented to the Department of Civil and Sanitary Engineering of the Massachusetts Institute of Technology.

  11. The Sports Column on National Daily Newspapers

    Directory of Open Access Journals (Sweden)

    Alp Çelik


    Full Text Available National daily newspapers aim to report detailed daily news. Sport pages of the newspapers contain sport columns and news about sport activities. The aim of this research was to investigate the sport columns appearing on sport pages of national daily newspapers published in Turkey. During the research process, nine national daily newspapers published in Turkey were reviewed for one year. The number of sport columns, publishing page, publishing space in cm. and accessibility of newspapers are ascertained. Newspaper field measurement, statistical and percentage calculations are made by Microsoft Excel. The study was completed with the transfer of the data obtained from Excel to Word as a document. According to the obtained data, regarding the news density on sport columns; Milliyet has the most news published, Cumhuriyet has the most news on front page, Haber Turk has the most space allocated and Zaman has been the most accessible newspaper.

  12. PRTR ion exchange vault column sampling

    International Nuclear Information System (INIS)

    Cornwell, B.C.


    This report documents ion exchange column sampling and Non Destructive Assay (NDA) results from activities in 1994, for the Plutonium Recycle Test Reactor (PRTR) ion exchange vault. The objective was to obtain sufficient information to prepare disposal documentation for the ion exchange columns found in the PRTR Ion exchange vault. This activity also allowed for the monitoring of the liquid level in the lower vault. The sampling activity contained five separate activities: (1) Sampling an ion exchange column and analyzing the ion exchange media for purpose of waste disposal; (2) Gamma and neutron NDA testing on ion exchange columns located in the upper vault; (3) Lower vault liquid level measurement; (4) Radiological survey of the upper vault; and (5) Secure the vault pending waste disposal

  13. Thermal post-buckling of slender composite and FGM columns ...

    Indian Academy of Sciences (India)

    G Venkateswara Rao

    column or plate. Structural members such as columns/beams are basic components in many light weight applications of the structural systems. The columns/ beams, having axially immovable ends, experience axial compressive mechanical load ...

  14. Three-Dimensional Modeling of the Detonation of a Munitions Stack and the Loading on an Adjacent Stack Protected by a Water Barricade

    National Research Council Canada - National Science Library

    Lottero, Richard


    This report describes the results of three-dimensional (3-D) hydrocode computations modeling the detonation of a donor munitions stack and the loading on and response of a protective water barricade and a nearby acceptor munitions stack...

  15. Capacity of columns with splice imperfections

    International Nuclear Information System (INIS)

    Popov, E.P.; Stephen, R.M.


    To study the behavior of spliced columns subjected to tensile forces simulating situations which may develop in an earthquake, all of the spliced specimens were tested to failure in tension after first having been subjected to large compressive loads. The results of these tests indicate that the lack of perfect contact at compression splices of columns may not be important, provided that the gaps are shimmed and welding is used to maintain the sections in alignment

  16. Gas Chromatograph Method Optimization Trade Study for RESOLVE: 20-meter Column v. 8-meter Column (United States)

    Huz, Kateryna


    RESOLVE is the payload on a Class D mission, Resource Prospector, which will prospect for water and other volatile resources at a lunar pole. The RESOLVE payload's primary scientific purpose includes determining the presence of water on the moon in the lunar regolith. In order to detect the water, a gas chromatograph (GC) will be used in conjunction with a mass spectrometer (MS). The goal of the experiment was to compare two GC column lengths and recommend which would be best for RESOLVE's purposes. Throughout the experiment, an Inficon Fusion GC and an Inficon Micro GC 3000 were used. The Fusion had a 20m long column with 0.25mm internal diameter (Id). The Micro GC 3000 had an 8m long column with a 0.32mm Id. By varying the column temperature and column pressure while holding all other parameters constant, the ideal conditions for testing with each column length in their individual instrument configurations were determined. The criteria used for determining the optimal method parameters included (in no particular order) (1) quickest run time, (2) peak sharpness, and (3) peak separation. After testing numerous combinations of temperature and pressure, the parameters for each column length that resulted in the most optimal data given my three criteria were selected. The ideal temperature and pressure for the 20m column were 95 C and 50psig. At this temperature and pressure, the peaks were separated and the retention times were shorter compared to other combinations. The Inficon Micro GC 3000 operated better at lower temperature mainly due to the shorter 8m column. The optimal column temperature and pressure were 70 C and 30psig. The Inficon Micro GC 3000 8m column had worse separation than the Inficon Fusion 20m column, but was able to separate water within a shorter run time. Therefore, the most significant tradeoff between the two column lengths was peak separation of the sample versus run time. After performing several tests, it was concluded that better

  17. Generalized diffraction-stack migration and filtering of coherent noise

    KAUST Repository

    Zhan, Ge


    We reformulate the equation of reverse-time migration so that it can be interpreted as summing data along a series of hyperbola-like curves, each one representing a different type of event such as a reflection or multiple. This is a generalization of the familiar diffraction-stack migration algorithm where the migration image at a point is computed by the sum of trace amplitudes along an appropriate hyperbola-like curve. Instead of summing along the curve associated with the primary reflection, the sum is over all scattering events and so this method is named generalized diffraction-stack migration. This formulation leads to filters that can be applied to the generalized diffraction-stack migration operator to mitigate coherent migration artefacts due to, e.g., crosstalk and aliasing. Results with both synthetic and field data show that generalized diffraction-stack migration images have fewer artefacts than those computed by the standard reverse-time migration algorithm. The main drawback is that generalized diffraction-stack migration is much more memory intensive and I/O limited than the standard reverse-time migration method. © 2014 European Association of Geoscientists & Engineers.

  18. Effect of flow parameters on flare stack generator noise

    International Nuclear Information System (INIS)

    Dinn, T.S.


    The SoundPLAN Computer Noise Model was used to determine the general effect of flare noise in a community adjacent to a petrochemical plant. Tests were conducted to determine the effect of process flow conditions and the pulsating flame on the flare stack generator noise from both a refinery flare and process flare. Flaring under normal plant operations, the flaring of fuel gas and the flaring of hydrogen were the three conditions that were tested. It was shown that the steam flow rate was the determining factor in the flare stack generated noise. Variations in the water seal level in the flare line surge tank increased or decreased the gas flowrate, which resulted in a pulsating flame. The period and amplitude of the pulsating noise from the flare stacks was determined by measuring several parameters. Flare stack noise oscillations were found to be greater for the process flare than for the refinery flare stack. It was suggested that minimizing the amount of steam fed to the flare and improving the burner design would minimize noise. 2 tabs., 6 figs

  19. Estimation of stacking fault and twin energies in transition metals

    International Nuclear Information System (INIS)

    Papon, Anne-Marie


    As twins and stacking faults play an important role in the plastic deformation of metals, the objective of this research thesis is, by using an as correct as possible description of band d state density, to assess the internal energy of twins and stacking faults in metals with a CFC, HC or CC crystal structure. If, in transition metals, cohesion mainly results from d electron attraction, other terms intervening in crystal equilibrium must also be taken into account. Thus, the author proposes a decomposition of cohesion energy. The geometry of twins and stacking faults in compact phases is defined, and energy calculations are presented and discussed. Alloying effects are then addressed, as well as a general comparison with available experimental results. After a geometric description of twins and stacking faults in CC structures, their energies are calculated for a Gaussian distribution of state density. For higher order moments, defect energy due to d orbital anisotropy is assessed, and then applied to energy and stability calculations in twins and stacking faults for various relaxed atomic configurations

  20. Interpretation of the lime column penetration test

    International Nuclear Information System (INIS)

    Liyanapathirana, D S; Kelly, R B


    Dry soil mix (DSM) columns are used to reduce the settlement and to improve the stability of embankments constructed on soft clays. During construction the shear strength of the columns needs to be confirmed for compliance with technical assumptions. A specialized blade shaped penetrometer known as the lime column probe, has been developed for testing DSM columns. This test can be carried out as a pull out resistance test (PORT) or a push in resistance test (PIRT). The test is considered to be more representative of average column shear strength than methods that test only a limited area of the column. Both PORT and PIRT tests require empirical correlations of measured resistance to an absolute measure of shear strength, in a similar manner to the cone penetration test. In this paper, finite element method is used to assess the probe factor, N, for the PORT test. Due to the large soil deformations around the probe, an Arbitrary Lagrangian Eulerian (ALE) based finite element formulation has been used. Variation of N with rigidity index and the friction at the probe-soil interface are investigated to establish a range for the probe factor.

  1. Development of spent salt treatment technology by zeolite column system. Performance evaluation of zeolite column

    International Nuclear Information System (INIS)

    Miura, Hidenori; Uozumi, Koichi


    At electrorefining process, fission products(FPs) accumulate in molten salt. To avoid influence on heating control by decay heat and enlargement of FP amount in the recovered fuel, FP elements must be removed from the spent salt of the electrorefining process. For the removal of the FPs from the spent salt, we are investigating the availability of zeolite column system. For obtaining the basic data of the column system, such as flow property and ion-exchange performance while high temperature molten salt is passing through the column, and experimental apparatus equipped with fraction collector was developed. By using this apparatus, following results were obtained. 1) We cleared up the flow parameter of column system with zeolite powder, such as flow rate control by argon pressure. 2) Zeolite 4A in the column can absorb cesium that is one of the FP elements in molten salt. From these results, we got perspective on availability of the zeolite column system. (author)

  2. Structural Decoupling and Disturbance Rejection in a Distillation Column

    DEFF Research Database (Denmark)

    Bahar, Mehrdad; Jantzen, Jan; Commault, C.


    Introduction, distillation column model, input-output decoupling, disturbance rejection, concluding remarks, references.......Introduction, distillation column model, input-output decoupling, disturbance rejection, concluding remarks, references....

  3. Continuous bind-and-elute protein A capture chromatography: Optimization under process scale column constraints and comparison to batch operation. (United States)

    Kaltenbrunner, Oliver; Diaz, Luis; Hu, Xiaochun; Shearer, Michael


    Recently, continuous downstream processing has become a topic of discussion and analysis at conferences while no industrial applications of continuous downstream processing for biopharmaceutical manufacturing have been reported. There is significant potential to increase the productivity of a Protein A capture step by converting the operation to simulated moving bed (SMB) mode. In this mode, shorter columns are operated at higher process flow and corresponding short residence times. The ability to significantly shorten the product residence time during loading without appreciable capacity loss can dramatically increase productivity of the capture step and consequently reduce the amount of Protein A resin required in the process. Previous studies have not considered the physical limitations of how short columns can be packed and the flow rate limitations due to pressure drop of stacked columns. In this study, we are evaluating the process behavior of a continuous Protein A capture column cycling operation under the known pressure drop constraints of a compressible media. The results are compared to the same resin operated under traditional batch operating conditions. We analyze the optimum system design point for a range of feed concentrations, bed heights, and load residence times and determine achievable productivity for any feed concentration and any column bed height. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 32:938-948, 2016. © 2016 American Institute of Chemical Engineers.

  4. A Butyl Methacrylate Monolithic Column Prepared In-Situ on a Microfluidic Chip and its Applications

    Directory of Open Access Journals (Sweden)

    Qiang Cao


    Full Text Available A butyl methacrylate (BMA monolithic column was polymerized in-situ with UV irradiation in an ultraviolet transparent PDMS micro-channel on a homemade micro-fluidic chip. Under the optimized conditions and using a typical polymerization mixture consisting of 75% porogenic solvents and 25% monomers, the BMA monolithic column was obtained as expected. The BET surface area ratio of the BMA monolithic column was 366 m2·g-1. The corresponding SEM images showed that the monolithic column material polymerized in a glass channel was composed of uniform pores and spherical particles with diameters ranging from 3 to 5 μm. The promethazine–luminal–potassium ferricyanide chemiluminescence system was selected for testing the capability of the column. A flow injection analytical technique–chemiluminescence (FIA–CL system on the microfluidic chip with a BMA monolithic column pretreatment unit was established to determine promethazine. Trace promethazine was enriched by the BMA monolithic column, with more than a 10-fold average enrichment ratio. The proposed method has a linear response concentration range of 1.0×10-8 - 1.0×10-6g·mL-1 and the detection limit was 1.6×10-9g·mL-1.

  5. A butyl methacrylate monolithic column prepared in-situ on a microfluidic chip and its applications. (United States)

    Xu, Yi; Zhang, Wenpin; Zeng, Ping; Cao, Qiang


    A butyl methacrylate (BMA) monolithic column was polymerized in-situ with UV irradiation in an ultraviolet transparent PDMS micro-channel on a homemade micro-fluidic chip. Under the optimized conditions and using a typical polymerization mixture consisting of 75% porogenic solvents and 25% monomers, the BMA monolithic column was obtained as expected. The BET surface area ratio of the BMA monolithic column was 366 m(2)·g(-1). The corresponding SEM images showed that the monolithic column material polymerized in a glass channel was composed of uniform pores and spherical particles with diameters ranging from 3 to 5 μm. The promethazine-luminal-potassium ferricyanide chemiluminescence system was selected for testing the capability of the column. A flow injection analytical technique-chemiluminescence (FIA-CL) system on the microfluidic chip with a BMA monolithic column pretreatment unit was established to determine promethazine. Trace promethazine was enriched by the BMA monolithic column, with more than a 10-fold average enrichment ratio. The proposed method has a linear response concentration range of 1.0×10(-8) - 1.0×10(-6)g·mL(-1) and the detection limit was 1.6×10(-9)g·mL(-1).

  6. Structural performance of circular columns confined by recycled GFRP stirrups and exposed to severe conditions

    Directory of Open Access Journals (Sweden)

    Mohamed S. Sayed


    Full Text Available Since 1980, Egyptian government investment has been directed to the infrastructure projects. Water supply and water drainage networks are among those projects which are very costly; therefore they are designed with a life span of about one hundred years. There is a new trend toward the use of durable and maintenance free systems. The “GFRP” pipes are one of the economic solutions if the project life span is taken into consideration. A number of investors currently produce the “GFRP” pipes in the Egyptian market and although they follow the latest technologies in their production lines, they still suffer 2–5% deficiency of their produced pipes which consequently regarded as rejected pipes. This percentage has a negative impact on the environmental and economical issues. This research is a trial to investigate the behavior of circular columns confined by GFRP stirrups and exposed to severe conditions. A number of waste pipes were randomly selected and sliced to be used as circular column transverse reinforcement. An experimental program consisting of ten short circular columns was designed to study the effect of corrosion, high degrees of temperature, and sulfate attack on the structural behavior of the axially loaded short circular columns. The experimental results showed that columns laterally reinforced by GFRP slices have a comparable behavior to conventionally reinforced concrete columns especially for those columns exposed to corrosion and sulfate attack.

  7. Design concept of a cryogenic distillation column cascade for a ITER scale fusion reactor

    International Nuclear Information System (INIS)

    Yamanishi, Toshihiko; Enoeda, Mikio; Okuno, Kenji


    A column cascade has been proposed for the fuel cycle of a ITER scale fusion reactor. The proposed cascade consists of three columns and has significant features: either top or bottom product is prior to the other for each column: it is avoided to withdraw side streams as products or feeds of down stream columns: and there is no recycle steam between the columns. In addition, the product purity of the cascade can be maintained against the changes of flow rates and compositions of feed streams just by adjusting the top and bottom flow rates. The control system has been designed for each column in the cascade. A key component in the prior product stream was selected, and the analysis method of this key component was proposed. The designed control system never brings instability as long as the concentration of the key component is measured with negligible time lag. The time lag for the measurement considerably affects the stability of the control system. A significant conclusion by the simulation in this work is that permissible time for the measurement is about 0.5 hour to obtain stable control. Hence, the analysis system using the gas chromatography is valid for control of the columns. (author)

  8. A Butyl Methacrylate Monolithic Column Prepared In-Situ on a Microfluidic Chip and its Applications (United States)

    Xu, Yi; Zhang, Wenpin; Zeng, Ping; Cao, Qiang


    A butyl methacrylate (BMA) monolithic column was polymerized in-situ with UV irradiation in an ultraviolet transparent PDMS micro-channel on a homemade micro-fluidic chip. Under the optimized conditions and using a typical polymerization mixture consisting of 75% porogenic solvents and 25% monomers, the BMA monolithic column was obtained as expected. The BET surface area ratio of the BMA monolithic column was 366 m2·g-1. The corresponding SEM images showed that the monolithic column material polymerized in a glass channel was composed of uniform pores and spherical particles with diameters ranging from 3 to 5 μm. The promethazine–luminal–potassium ferricyanide chemiluminescence system was selected for testing the capability of the column. A flow injection analytical technique–chemiluminescence (FIA–CL) system on the microfluidic chip with a BMA monolithic column pretreatment unit was established to determine promethazine. Trace promethazine was enriched by the BMA monolithic column, with more than a 10-fold average enrichment ratio. The proposed method has a linear response concentration range of 1.0×10-8 - 1.0×10-6g·mL-1 and the detection limit was 1.6×10-9g·mL-1. PMID:22412320

  9. Column Selection for Biomedical Analysis Supported by Column Classification Based on Four Test Parameters. (United States)

    Plenis, Alina; Rekowska, Natalia; Bączek, Tomasz


    This article focuses on correlating the column classification obtained from the method created at the Katholieke Universiteit Leuven (KUL), with the chromatographic resolution attained in biomedical separation. In the KUL system, each column is described with four parameters, which enables estimation of the FKUL value characterising similarity of those parameters to the selected reference stationary phase. Thus, a ranking list based on the FKUL value can be calculated for the chosen reference column, then correlated with the results of the column performance test. In this study, the column performance test was based on analysis of moclobemide and its two metabolites in human plasma by liquid chromatography (LC), using 18 columns. The comparative study was performed using traditional correlation of the FKUL values with the retention parameters of the analytes describing the column performance test. In order to deepen the comparative assessment of both data sets, factor analysis (FA) was also used. The obtained results indicated that the stationary phase classes, closely related according to the KUL method, yielded comparable separation for the target substances. Therefore, the column ranking system based on the FKUL-values could be considered supportive in the choice of the appropriate column for biomedical analysis.

  10. Reliability assessment of germanium gate stacks with promising initial characteristics (United States)

    Lu, Cimang; Lee, Choong Hyun; Nishimura, Tomonori; Nagashio, Kosuke; Toriumi, Akira


    This work reports on the reliability assessment of germanium (Ge) gate stacks with promising initial electrical properties, with focus on trap generation under a constant electric stress field (Estress). Initial Ge gate stack properties do not necessarily mean highly robust reliability when it is considered that traps are newly generated under high Estress. A small amount of yttrium- or scandium oxide-doped GeO2 (Y-GeO2 or Sc-GeO2, respectively) significantly reduces trap generation in Ge gate stacks without deterioration of the interface. This is explained by the increase in the average coordination number (Nav) of the modified GeO2 network that results from the doping.

  11. Edge-edge interactions in stacked graphene nanoplatelets

    Energy Technology Data Exchange (ETDEWEB)

    Cruz Silva, Eduardo [ORNL; Terrones Maldonado, Humberto [ORNL; Terrones Maldonado, Mauricio [ORNL; Jia, Xiaoting [Massachusetts Institute of Technology (MIT); Sumpter, Bobby G [ORNL; Dresselhaus, M [Massachusetts Institute of Technology (MIT); Meunier, V. [Rensselaer Polytechnic Institute (RPI)


    High-resolution transmission electron microscopy (HRTEM) studies show the dynamics of small graphene platelets on larger graphene layers. The platelets move nearly freely to eventually lock in at well-defined positions close to the edges of the larger underlying graphene sheet. While such movement is driven by a shallow potential energy surface described by an interplane interaction, the lock-in position occurs by via edge-edge interactions of the platelet and the graphene surface located underneath. Here we quantitatively study this behavior using van der Waals density functional calculations. Local interactions at the open edges are found to dictate stacking configurations that are different from Bernal (AB) stacking. These stacking configurations are known to be otherwise absent in edge-free two-dimensional (2D) graphene. The results explain the experimentally observed platelet dynamics and provide a detailed account of the new electronic properties of these combined systems.

  12. Magneto-optical properties of ABC-stacked trilayer graphene. (United States)

    Lin, Yi-Ping; Lin, Chiun-Yan; Ho, Yen-Hung; Do, Thi-Nga; Lin, Ming-Fa


    The generalized tight-binding model is developed to investigate the magneto-optical absorption spectra of ABC-stacked trilayer graphene. The absorption peaks can be classified into nine categories of inter-Landau-level optical excitations, including three intra-group and six inter-group ones. Most of them belong to the twin-peak structures because of the asymmetric Landau level spectrum. The threshold absorption peak alone comes from a certain excitation channel, and its frequency is associated with a specific interlayer atomic interaction. The Landau-level anticrossings cause extra absorption peaks. Moreover, a simple relationship between the absorption frequency and the field strength is absent. The magneto-optical properties of ABC-stacked trilayer graphene are totally different from those of AAA- and ABA-stacked ones, such as the number, intensity and frequency of absorption peaks.

  13. Thermoacoustic design using stem of goose down stack (United States)

    Farikhah, Irna; Ristanto, Sigit; Idrus, Hadiyati; Kaltsum, Ummi; Faisal, Affandi; Setiawan, Ihsan; Setio Utomo, Agung Bambang


    Many refrigerators using CFC as a refrigerant are seen as the cause of the depletion of ozone. Hence, thermoacoustic was chosen as an alternative refrigerator that safe for environment. There are many variable that influenced the optimization of thermoacoustic design. One of them is thermal conductivity of material of stack. The Stack material must have a low thermal conductivity. In this research we used organic stack made of stem of goose down. It has superior thermal insulating. It means that they have the lowest thermal conductivity. The system uses no refrigerant or compressor, and the only mechanical moving part is the loudspeaker connected to a signal generator that produces the acoustic. The working fluid is air and the material of resonator is stainless steel. A series test on the laboratory found that there is a decrease of 5°C in temperature for about 2 minutes.

  14. The measurement of power reactor stack releases under accident conditions

    International Nuclear Information System (INIS)

    Stroem, L.


    The performance of a typical Swedish monitor for ventilation stack radioactivity releases is examined critically with respect to accident generated radioactive particles. The conditions in the stack, particle character, and the monitor design are considered. A large LOCA outside the containment leads to high relative humidity, and high temperature, or mist in the stack. A small external LOCA results in a moderate increase in temperature and humidity, and condensing conditions only with reduced ventilation. Particle size and stickiness are estimated for different types of accident. A particle is sticky if it adheres after contact with a solid, smooth, dry, and clean surface. The monitor performance is concluded to be poor for large, sticky particles, like mist droplets. Dense aerosols, like fire smoke, will plug the sampling filter. Non-sticky particles are generally sampled with acceptable accuracy. (au)

  15. Piezoelectric stack actuator parameter extraction with hysteresis compensation

    DEFF Research Database (Denmark)

    Zsurzsan, Tiberiu-Gabriel; Mangeot, Charles; Andersen, Michael A. E.


    The Piezoelectric Actuator Drive (PAD) is a type of rotary motor that transforms the linear motion of piezoelectric stack actuators into a precise rotational motion. The very high stiffness of the actuators employed make this type of motor suited for open-loop control, but the inherent hysteresis...... exhibited by piezoelectric ceramics causes losses. Therefore, this paper presents a straightforward method to measure piezoelectric stack actuator equiv- alent parameters that includes nonlinearities. By folding the nonlinearities into a newly-defined cou- pling coefficient, the inherent hysteretic behavior...... of piezoelectric stack actuators can be greatly reduced through precompensation. Experimental results show a fitting accuracy of 98.8 % between the model and measurements and a peak absolute error reduction by a factor of 10 compared to the manufacturer- provided parameter. This method improves both the static...

  16. Stacking and discontinuous buffers in capillary zone electrophoresis. (United States)

    Shihabi, Z K


    Discontinuous buffers for capillary zone electrophoresis (CZE) can be used under less rigid conditions compared to those for isotachophoresis for stacking. They can be prepared simply by modifying the sample itself, either by addition of small inorganic ions, low conductivity diluents, or both, and also by adjusting its pH, meanwhile injecting a large volume on the capillary. Zwitterionic and organic-based buffers such as triethanolamine and tris(hydroxymethyl)aminomethane (Tris) are well suited for stacking due to their low conductivity, provided the buffer is discontinuous as demonstrated here. A simple mechanism based on discontinuous buffers is described to explain many of the observed stacking types in CZE, pointing out the many similarities to transient isotachophoresis.

  17. Salt Concentration Differences Alter Membrane Resistance in Reverse Electrodialysis Stacks

    KAUST Repository

    Geise, Geoffrey M.


    Membrane ionic resistance is usually measured by immersing the membrane in a salt solution at a single, fixed concentration. While salt concentration is known to affect membrane resistance when the same concentration is used on both sides of the membrane, little is known about membrane resistance when the membrane is placed between solutions of different concentrations, such as in a reverse electrodialysis (RED) stack. Ionic resistance measurements obtained using Selemion CMV and AMV that separated sodium chloride and ammonium bicarbonate solutions of different concentrations were greater than those measured using only the high-concentration solution. Measured RED stack resistances showed good agreement with resistances calculated using an equivalent series resistance model, where the membranes accounted for 46% of the total stack resistance. The high area resistance of the membranes separating different salt concentration solutions has implications for modeling and optimizing membranes used in RED systems.

  18. Continued SOFC cell and stack technology and improved production methods

    Energy Technology Data Exchange (ETDEWEB)

    Wandel, M.; Brodersen, K.; Phair, J. (and others)


    Within this project significant results are obtained on a number of very diverse areas ranging from development of cell production, metallic creep in interconnect to assembling and test of stacks with foot print larger than 500 cm2. Out of 38 milestones 28 have been fulfilled and 10 have been partly fulfilled. This project has focused on three main areas: 1) The continued cell development and optimization of manufacturing processes aiming at production of large foot-print cells, improving cell performance and development environmentally more benign production methods. 2) Stack technology - especially stacks with large foot print and improving the stack design with respect to flow geometry and gas leakages. 3) Development of stack components with emphasis on sealing (for 2G as well as 3G), interconnect (coat, architecture and creep) and test development. Production of cells with a foot print larger than 500 cm2 is very difficult due to the brittleness of the cells and great effort has been put into this topic. Eight cells were successfully produced making it possible to assemble and test a real stack thereby giving valuable results on the prospects of stacks with large foot print. However, the yield rate is very low and a significant development to increase this yield lies ahead. Several lessons were learned on the stack level regarding 'large foot print' stacks. Modelling studies showed that the width of the cell primarily is limited by production and handling of the cell whereas the length (in the flow direction) is limited by e.g. pressure drop and necessary manifolding. The optimal cell size in the flow direction was calculated to be between approx20 cm and < 30 cm. From an economical point of view the production yield is crucial and stacks with large foot print cell area are only feasible if the cell production yield is significantly enhanced. Co-casting has been pursued as a production technique due to the possibilities in large scale production

  19. Electrically Conductive and Protective Coating for Planar SOFC Stacks

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Jung-Pyung; Stevenson, Jeffry W.


    Ferritic stainless steels are preferred interconnect materials for intermediate temperature SOFCs because of their resistance to oxidation, high formability and low cost. However, their protective oxide layer produces Cr-containing volatile species at SOFC operating temperatures and conditions, which can cause cathode poisoning. Electrically conducting spinel coatings have been developed to prevent cathode poisoning and to maintain an electrically conductive pathway through SOFC stacks. However, this coating is not compatible with the formation of stable, hermetic seals between the interconnect frame component and the ceramic cell. Thus, a new aluminizing process has been developed by PNNL to enable durable sealing, prevent Cr evaporation, and maintain electrical insulation between stack repeat units. Hence, two different types of coating need to have stable operation of SOFC stacks. This paper will focus on the electrically conductive coating process. Moreover, an advanced coating process, compatible with a non-electrically conductive coating will be

  20. Mathematical Modeling of Column-Base Connections under Monotonic Loading

    Directory of Open Access Journals (Sweden)

    Gholamreza Abdollahzadeh


    Full Text Available Some considerable damage to steel structures during the Hyogo-ken Nanbu Earthquake occurred. Among them, many exposed-type column bases failed in several consistent patterns, such as brittle base plate fracture, excessive bolt elongation, unexpected early bolt failure, and inferior construction work, etc. The lessons from these phenomena led to the need for improved understanding of column base behavior. Joint behavior must be modeled when analyzing semi-rigid frames, which is associated with a mathematical model of the moment–rotation curve. The most accurate model uses continuous nonlinear functions. This article presents three areas of steel joint research: (1 analysis methods of semi-rigid joints; (2 prediction methods for the mechanical behavior of joints; (3 mathematical representations of the moment–rotation curve. In the current study, a new exponential model to depict the moment–rotation relationship of column base connection is proposed. The proposed nonlinear model represents an approach to the prediction of M–θ curves, taking into account the possible failure modes and the deformation characteristics of the connection elements. The new model has three physical parameters, along with two curve-fitted factors. These physical parameters are generated from dimensional details of the connection, as well as the material properties. The M–θ curves obtained by the model are compared with published connection tests and 3D FEM research. The proposed mathematical model adequately comes close to characterizing M–θ behavior through the full range of loading/rotations. As a result, modeling of column base connections using the proposed mathematical model can give crucial beforehand information, and overcome the disadvantages of time consuming workmanship and cost of experimental studies.

  1. Performance of lap splices in large-scale column specimens affected by ASR and/or DEF-extension phase. (United States)


    A large experimental program, consisting of the design, construction, curing, exposure, and structural load : testing of 16 large-scale column specimens with a critical lap splice region that were influenced by varying : stages of alkali-silica react...

  2. Maintaining consistency in distributed systems (United States)

    Birman, Kenneth P.


    In systems designed as assemblies of independently developed components, concurrent access to data or data structures normally arises within individual programs, and is controlled using mutual exclusion constructs, such as semaphores and monitors. Where data is persistent and/or sets of operation are related to one another, transactions or linearizability may be more appropriate. Systems that incorporate cooperative styles of distributed execution often replicate or distribute data within groups of components. In these cases, group oriented consistency properties must be maintained, and tools based on the virtual synchrony execution model greatly simplify the task confronting an application developer. All three styles of distributed computing are likely to be seen in future systems - often, within the same application. This leads us to propose an integrated approach that permits applications that use virtual synchrony with concurrent objects that respect a linearizability constraint, and vice versa. Transactional subsystems are treated as a special case of linearizability.

  3. Domestic wastewater treatment and power generation in continuous flow air-cathode stacked microbial fuel cell: Effect of series and parallel configuration. (United States)

    Estrada-Arriaga, Edson Baltazar; Hernández-Romano, Jesús; García-Sánchez, Liliana; Guillén Garcés, Rosa Angélica; Bahena-Bahena, Erick Obed; Guadarrama-Pérez, Oscar; Moeller Chavez, Gabriela Eleonora


    In this study, a continuous flow stack consisting of 40 individual air-cathode MFC units was used to determine the performance of stacked MFC during domestic wastewater treatment operated with unconnected individual MFC and in series and parallel configuration. The voltages obtained from individual MFC units were of 0.08-1.1 V at open circuit voltage, while in series connection, the maximum power and current density were 2500 mW/m 2 and 500 mA/m 2 (4.9 V), respectively. In parallel connection, the maximum power and current density was 5.8 mW/m 2 and 24 mA/m 2 , respectively. When the cells were not connected to each other MFC unit, the main bacterial species found in the anode biofilms were Bacillus and Lysinibacillus. After switching from unconnected to series and parallel connections, the most abundant species in the stacked MFC were Pseudomonas aeruginosa, followed by different Bacilli classes. This study demonstrated that when the stacked MFC was switched from unconnected to series and parallel connections, the pollutants removal, performance electricity and microbial community changed significantly. Voltages drops were observed in the stacked MFC, which was mainly limited by the cathodes. These voltages loss indicated high resistances within the stacked MFC, generating a parasitic cross current. Copyright © 2018 Elsevier Ltd. All rights reserved.

  4. Multi-Column Experimental Test Bed for Xe/Kr Separation

    Energy Technology Data Exchange (ETDEWEB)

    Greenhalgh, Mitchell Randy [Idaho National Lab. (INL), Idaho Falls, ID (United States); Garn, Troy Gerry [Idaho National Lab. (INL), Idaho Falls, ID (United States); Welty, Amy Keil [Idaho National Lab. (INL), Idaho Falls, ID (United States); Lyon, Kevin Lawrence [Idaho National Lab. (INL), Idaho Falls, ID (United States); Watson, Tony Leroy [Idaho National Lab. (INL), Idaho Falls, ID (United States)ry


    Previous research studies have shown that INL-developed engineered form sorbents are capable of capturing both Kr and Xe from various composite gas streams. The previous experimental test bed provided single column testing for capacity evaluations over a broad temperature range. To advance research capabilities, the employment of an additional column to study selective capture of target species to provide a defined final gas composition for waste storage was warranted. The second column addition also allows for compositional analyses of the final gas product to provide for final storage determinations. The INL krypton capture system was modified by adding an additional adsorption column in order to create a multi-column test bed. The purpose of this modification was to investigate the separation of xenon from krypton supplied as a mixed gas feed. The extra column was placed in a Stirling Ultra-low Temperature Cooler, capable of controlling temperatures between 190 and 253K. Additional piping and valves were incorporated into the system to allow for a variety of flow path configurations. The new column was filled with the AgZ-PAN sorbent which was utilized as the capture medium for xenon while allowing the krypton to pass through. The xenon-free gas stream was then routed to the cryostat filled with the HZ-PAN sorbent to capture the krypton at 191K. Selectivities of xenon over krypton were determined using the new column to verify the system performance and to establish the operating conditions required for multi-column testing. Results of these evaluations verified that the system was operating as designed and also demonstrated that AgZ-PAN exhibits excellent selectivity for xenon over krypton in air at or near room temperature. Two separation tests were performed utilizing a feed gas consisting of 1000 ppmv xenon and 150 ppmv krypton with the balance being made up of air. The AgZ-PAN temperature was held at 295 or 253K while the HZ-PAN was held at 191K for both

  5. Nuclear fuel rod with retainer for pellet stack

    International Nuclear Information System (INIS)

    Cloue, J.M.


    The rod, usable in pressurized water reactors, comprises a stack of fuel pellets and means holding the stack against an end plug of the fuel can during handling operations. These means include a radially expansive element (retainer) of which the shape is so that when it is free at ambient temperature it is gripping the inside of the casing, and a temperature sensitive spacer which contracts the retainer to release it from the casing at a temperature between the ambient and the operating temperature of a reactor [fr

  6. Implementing cloud storage with OpenStack Swift

    CERN Document Server

    Rajana, Kris; Varma, Sreedhar


    This tutorial-based book has a step-by-step approach for each topic, ensuring it is thoroughly covered and easy to follow. If you are an IT administrator who wants to enter the world of cloud storage using OpenStack Swift, then this book is ideal for you. Whether your job is to build, manage, or use OpenStack Swift, this book is an ideal way to move your career ahead. Only basic Linux and server technology skills are expected, to take advantage of this book.

  7. Hardware Evaluation of the Horizontal Exercise Fixture with Weight Stack (United States)

    Newby, Nate; Leach, Mark; Fincke, Renita; Sharp, Carwyn


    HEF with weight stack seems to be a very sturdy and reliable exercise device that should function well in a bed rest training setting. A few improvements should be made to both the hardware and software to improve usage efficiency, but largely, this evaluation has demonstrated HEF's robustness. The hardware offers loading to muscles, bones, and joints, potentially sufficient to mitigate the loss of muscle mass and bone mineral density during long-duration bed rest campaigns. With some minor modifications, the HEF with weight stack equipment provides the best currently available means of performing squat, heel raise, prone row, bench press, and hip flexion/extension exercise in a supine orientation.

  8. Experimental 1 kW 20 cell PEFC stack

    Energy Technology Data Exchange (ETDEWEB)

    Buechi, F.N.; Marmy, C.A.; Scherer, G.G. [Paul Scherrer Inst. (PSI), Villigen (Switzerland); Ruge, M. [Swiss Federal Inst. of Technology (ETH), Zuerich (Switzerland)


    A 20-cell PEFC stack was designed and built. Resin impregnated graphite was used as bipolar plate material. The air cooling of the stack was optimized by introducing high surface structures into the open space of the cooling plates. At {eta} (H{sub 2} LHV) = 0.5 a power of 880 W was obtained under conditions of low gas-pressures of 1.15 bar{sub a}. The auxiliary power for process air supply and cooling at 880 W power is less than 7% of the power output, indicating that the described system may be operated at a high efficiency. (author) 5 figs., 2 refs.

  9. Second Generation Small Pixel Technology Using Hybrid Bond Stacking (United States)

    Venezia, Vincent C.; Hsiung, Alan Chih-Wei; Yang, Wu-Zang; Zhang, Yuying; Zhao, Cheng; Lin, Zhiqiang; Grant, Lindsay A.


    In this work, OmniVision’s second generation (Gen2) of small-pixel BSI stacking technologies is reviewed. The key features of this technology are hybrid-bond stacking, deeper back-side, deep-trench isolation, new back-side composite metal-oxide grid, and improved gate oxide quality. This Gen2 technology achieves state-of-the-art low-light image-sensor performance for 1.1, 1.0, and 0.9 µm pixel products. Additional improvements on this technology include less than 100 ppm white-pixel process and a high near-infrared (NIR) QE technology. PMID:29495272

  10. Second Generation Small Pixel Technology Using Hybrid Bond Stacking


    Vincent C. Venezia; Alan Chih-Wei Hsiung; Wu-Zang Yang; Yuying Zhang; Cheng Zhao; Zhiqiang Lin; Lindsay A. Grant


    In this work, OmniVision’s second generation (Gen2) of small-pixel BSI stacking technologies is reviewed. The key features of this technology are hybrid-bond stacking, deeper back-side, deep-trench isolation, new back-side composite metal-oxide grid, and improved gate oxide quality. This Gen2 technology achieves state-of-the-art low-light image-sensor performance for 1.1, 1.0, and 0.9 µm pixel products. Additional improvements on this technology include less than 100 ppm white-pixel process a...

  11. Second Generation Small Pixel Technology Using Hybrid Bond Stacking

    Directory of Open Access Journals (Sweden)

    Vincent C. Venezia


    Full Text Available In this work, OmniVision’s second generation (Gen2 of small-pixel BSI stacking technologies is reviewed. The key features of this technology are hybrid-bond stacking, deeper back-side, deep-trench isolation, new back-side composite metal-oxide grid, and improved gate oxide quality. This Gen2 technology achieves state-of-the-art low-light image-sensor performance for 1.1, 1.0, and 0.9 µm pixel products. Additional improvements on this technology include less than 100 ppm white-pixel process and a high near-infrared (NIR QE technology.

  12. Second Generation Small Pixel Technology Using Hybrid Bond Stacking. (United States)

    Venezia, Vincent C; Hsiung, Alan Chih-Wei; Yang, Wu-Zang; Zhang, Yuying; Zhao, Cheng; Lin, Zhiqiang; Grant, Lindsay A


    In this work, OmniVision's second generation (Gen2) of small-pixel BSI stacking technologies is reviewed. The key features of this technology are hybrid-bond stacking, deeper back-side, deep-trench isolation, new back-side composite metal-oxide grid, and improved gate oxide quality. This Gen2 technology achieves state-of-the-art low-light image-sensor performance for 1.1, 1.0, and 0.9 µm pixel products. Additional improvements on this technology include less than 100 ppm white-pixel process and a high near-infrared (NIR) QE technology.

  13. Band engineering in transition metal dichalcogenides: Stacked versus lateral heterostructures

    International Nuclear Information System (INIS)

    Guo, Yuzheng; Robertson, John


    We calculate a large difference in the band alignments for transition metal dichalcogenide (TMD) heterojunctions when arranged in the stacked layer or lateral (in-plane) geometries, using direct supercell calculations. The stacked case follows the unpinned limit of the electron affinity rule, whereas the lateral geometry follows the strongly pinned limit of alignment of charge neutrality levels. TMDs therefore provide one of the few clear tests of band alignment models, whereas three-dimensional semiconductors give less stringent tests because of accidental chemical trends in their properties.

  14. Simulation of Collective Excitations in Long Josephson Junction Stacks (United States)

    Rahmonov, Ilhom; Shukrinov, Yury; Atanasova, Pavlina; Zemlyanaya, Elena; Streltsova, Oksana; Zuev, Maxim; Plecenik, Andrej; Irie, Akinobu


    The phase dynamics of a stack of long Josephson junctions has been studied. Both inductive and capacitive couplings between Josephson junctions have been taken into account in the calculations. The IV-curve, the dependence on the bias current of the radiation power and dynamics of each JJs of the stack have been investigated. The coexistence of the charge traveling wave and fluxon states has been observed. This state can be considered as a new collective excitation in the system of coupled Josephson junctions. We demonstrate that the observed collective excitation leads to the decrease of radiation power from the system.

  15. Spectrally tunable linear polarization rotation using stacked metallic metamaterials (United States)

    Romain, Xavier; Baida, Fadi I.; Boyer, Philippe


    We make a theoretical study of the transmission properties of a stack of metallic metamaterials and show that is able to achieve a perfect transmission selectively exhibiting broadband (Q {10}5) polarization rotation. We especially highlight how the arrangement of the stacked structure, as well as the metamaterial unit cell geometry, has a large influence on transmission in the spectral domain. For this purpose, we use an extended analytical Jones formalism that allows us to obtain a rigorous and analytical expression of the transmission. Such versatile structures could find potential applications in polarimetry or in the control of light polarization for THz waves.

  16. Recent advances in column switching sample preparation in bioanalysis. (United States)

    Kataoka, Hiroyuki; Saito, Keita


    Column switching techniques, using two or more stationary phase columns, are useful for trace enrichment and online automated sample preparation. Target fractions from the first column are transferred online to a second column with different properties for further separation. Column switching techniques can be used to determine the analytes in a complex matrix by direct sample injection or by simple sample treatment. Online column switching sample preparation is usually performed in combination with HPLC or capillary electrophoresis. SPE or turbulent flow chromatography using a cartridge column and in-tube solid-phase microextraction using a capillary column have been developed for convenient column switching sample preparation. Furthermore, various micro-/nano-sample preparation devices using new polymer-coating materials have been developed to improve extraction efficiency. This review describes current developments and future trends in novel column switching sample preparation in bioanalysis, focusing on innovative column switching techniques using new extraction devices and materials.


    International Nuclear Information System (INIS)

    Erkal, Denis; Gnedin, Nickolay Y.; Kravtsov, Andrey V.


    We study the high column density regime of the H I column density distribution function and argue that there are two distinct features: a turnover at N H I ≈ 10 21 cm –2 , which is present at both z = 0 and z ≈ 3, and a lack of systems above N H I ≈ 10 22 cm –2 at z = 0. Using observations of the column density distribution, we argue that the H I-H 2 transition does not cause the turnover at N H I ≈ 10 21 cm –2 but can plausibly explain the turnover at N H I ∼> 10 22 cm –2 . We compute the H I column density distribution of individual galaxies in the THINGS sample and show that the turnover column density depends only weakly on metallicity. Furthermore, we show that the column density distribution of galaxies, corrected for inclination, is insensitive to the resolution of the H I map or to averaging in radial shells. Our results indicate that the similarity of H I column density distributions at z = 3 and 0 is due to the similarity of the maximum H I surface densities of high-z and low-z disks, set presumably by universal processes that shape properties of the gaseous disks of galaxies. Using fully cosmological simulations, we explore other candidate physical mechanisms that could produce a turnover in the column density distribution. We show that while turbulence within giant molecular clouds cannot affect the damped Lyα column density distribution, stellar feedback can affect it significantly if the feedback is sufficiently effective in removing gas from the central 2-3 kpc of high-redshift galaxies. Finally, we argue that it is meaningful to compare column densities averaged over ∼ kpc scales with those estimated from quasar spectra that probe sub-pc scales due to the steep power spectrum of H I column density fluctuations observed in nearby galaxies.

  18. Contributions to reversed-phase column selectivity: III. Column hydrogen-bond basicity. (United States)

    Carr, P W; Dolan, J W; Dorsey, J G; Snyder, L R; Kirkland, J J


    Column selectivity in reversed-phase chromatography (RPC) can be described in terms of the hydrophobic-subtraction model, which recognizes five solute-column interactions that together determine solute retention and column selectivity: hydrophobic, steric, hydrogen bonding of an acceptor solute (i.e., a hydrogen-bond base) by a stationary-phase donor group (i.e., a silanol), hydrogen bonding of a donor solute (e.g., a carboxylic acid) by a stationary-phase acceptor group, and ionic. Of these five interactions, hydrogen bonding between donor solutes (acids) and stationary-phase acceptor groups is the least well understood; the present study aims at resolving this uncertainty, so far as possible. Previous work suggests that there are three distinct stationary-phase sites for hydrogen-bond interaction with carboxylic acids, which we will refer to as column basicity I, II, and III. All RPC columns exhibit a selective retention of carboxylic acids (column basicity I) in varying degree. This now appears to involve an interaction of the solute with a pair of vicinal silanols in the stationary phase. For some type-A columns, an additional basic site (column basicity II) is similar to that for column basicity I in primarily affecting the retention of carboxylic acids. The latter site appears to be associated with metal contamination of the silica. Finally, for embedded-polar-group (EPG) columns, the polar group can serve as a proton acceptor (column basicity III) for acids, phenols, and other donor solutes. Copyright © 2015 Elsevier B.V. All rights reserved.

  19. The performance of a grid-tied microgrid with hydrogen storage and a hydrogen fuel cell stack

    International Nuclear Information System (INIS)

    Zhang, Linfeng; Xiang, Jing


    Highlights: • Two microgrids with different structure are simulated. • Their performance are comprehensively evaluated and compared. • The one with DES and a FC stack has high environmental and quality indexes. - Abstract: In a heat-power system, the use of distributed energy generation and storage not only improves system’s efficiency and reliability but also reduce the emission. This paper is focused on the comprehensive performance evaluation of a grid-tied microgrid, which consists of a PV system, a hydrogen fuel cell stack, a PEM electrolyzer, and a hydrogen tank. Electricity and heat are generated in this system, to meet the local electric and heat demands. The surplus electricity can be stored as hydrogen, which is supplied to the fuel cell stack to generate heat and power as needed. The performance of the microgrid is comprehensively evaluated and is compared with another microgrid without a fuel cell stack. As a result, the emission and the service quality in the first system are higher than those in the second one. But they both have the same overall performance

  20. Preparation and characterization of porphyrin-polythiophene stacked films as prepared by electrochemical method under stirring condition

    International Nuclear Information System (INIS)

    Sugawa, Kosuke; Akiyama, Tsuyoshi; Yamada, Sunao


    Porphyrin-polythiophene (pTh) stacked films consisting of meso-tetrathienylporphyrin (TThP) and bithiophene (BiTh) were prepared on transparent indium-tin-oxide (ITO) electrodes by sequential electrochemical scanning of applied potential between 0 and + 2 V vs Ag wire in the electrolyte solution of BiTh and TThP under stirring condition. First, the pTh films were prepared by electrochemical polymerization and then TThP was incorporated into the as-prepared pTh film by subsequent electrochemical scanning as described above in the TThP solution. The operation of solution stirring during electrochemical scanning achieved the formation of robust stacked films. UV/Vis and fluorescence spectra confirmed that the amount of TThP moiety increased with increasing the number of electrochemical scanning cycles in the TThP solution. In order to evaluate the incorporation profile of TThP, surface analyses and depth profiles of stacked films were carried out by XPS spectroscopy. The results suggested that all films formed porphyrin-polythiophene stacked structure precisely, and that TThP was exclusively incorporated around the outermost region of the pTh film

  1. From the components to the stack. Developing and designing 5kW HT-PEFC stacks; Von der Komponente zum Stack. Entwicklung und Auslegung von HT-PEFC-Stacks der 5 kW-Klasse

    Energy Technology Data Exchange (ETDEWEB)

    Bendzulla, Anne


    The aim of the present project is to develop a stack design for a 5-kW HTPEFC system. First, the state of the art of potential materials and process designs will be discussed for each component. Then, using this as a basis, three potential stack designs with typical attributes will be developed and assessed in terms of practicality with the aid of a specially derived evaluation method. Two stack designs classified as promising will be discussed in detail, constructed and then characterized using short stack tests. Comparing the stack designs reveals that both designs are fundamentally suitable for application in a HT-PEFC system with on-board supply. However, some of the performance data differ significantly for the two stack designs. The preferred stack design for application in a HT-PEFC system is characterized by robust operating behaviour and reproducible high-level performance data. Moreover, in compact constructions (120 W/l at 60 W/kg), the stack design allows flexible cooling with thermal oil or air, which can be adapted to suit specific applications. Furthermore, a defined temperature gradient can be set during operation, allowing the CO tolerance to be increased by up to 10 mV. The short stack design developed within the scope of the present work therefore represents an ideal basis for developing a 5-kW HT-PEFC system. Topics for further research activities include improving the performance by reducing weight and/or volume, as well as optimizing the heat management. The results achieved within the framework of this work clearly show that HTPEFC stacks have the potential to play a decisive role in increasing efficiency in the future, particularly when combined with an on-board supply system. (orig.) [German] Ziel der vorliegenden Arbeit ist die Entwicklung eines Stackkonzeptes fuer ein 5 kW-HT-PEFC System. Dazu wird zunaechst fuer jede Komponente der Stand der Technik moeglicher Materialien und Prozesskonzepte diskutiert. Darauf aufbauend werden drei

  2. Decentralized Consistent Updates in SDN

    KAUST Repository

    Nguyen, Thanh Dang


    We present ez-Segway, a decentralized mechanism to consistently and quickly update the network state while preventing forwarding anomalies (loops and blackholes) and avoiding link congestion. In our design, the centralized SDN controller only pre-computes information needed by the switches during the update execution. This information is distributed to the switches, which use partial knowledge and direct message passing to efficiently realize the update. This separation of concerns has the key benefit of improving update performance as the communication and computation bottlenecks at the controller are removed. Our evaluations via network emulations and large-scale simulations demonstrate the efficiency of ez-Segway, which compared to a centralized approach, improves network update times by up to 45% and 57% at the median and the 99th percentile, respectively. A deployment of a system prototype in a real OpenFlow switch and an implementation in P4 demonstrate the feasibility and low overhead of implementing simple network update functionality within switches.

  3. Vertebral Column Resection for Rigid Spinal Deformity. (United States)

    Saifi, Comron; Laratta, Joseph L; Petridis, Petros; Shillingford, Jamal N; Lehman, Ronald A; Lenke, Lawrence G


    Broad narrative review. To review the evolution, operative technique, outcomes, and complications associated with posterior vertebral column resection. A literature review of posterior vertebral column resection was performed. The authors' surgical technique is outlined in detail. The authors' experience and the literature regarding vertebral column resection are discussed at length. Treatment of severe, rigid coronal and/or sagittal malalignment with posterior vertebral column resection results in approximately 50-70% correction depending on the type of deformity. Surgical site infection rates range from 2.9% to 9.7%. Transient and permanent neurologic injury rates range from 0% to 13.8% and 0% to 6.3%, respectively. Although there are significant variations in EBL throughout the literature, it can be minimized by utilizing tranexamic acid intraoperatively. The ability to correct a rigid deformity in the spine relies on osteotomies. Each osteotomy is associated with a particular magnitude of correction at a single level. Posterior vertebral column resection is the most powerful posterior osteotomy method providing a successful correction of fixed complex deformities. Despite meticulous surgical technique and precision, this robust osteotomy technique can be associated with significant morbidity even in the most experienced hands.

  4. Parametric resonance in concrete beam-columns

    Directory of Open Access Journals (Sweden)

    Mamta R. Sharma

    Full Text Available A dynamic instability, called parametric resonance, is exhibited by undampedelastic beam-columns when under the action of pulsating axial force. The scope of the existing theory of parametric resonance is restricted to physically linear beam-columns undergoing finite lateral displacements. In this Paper, the dynamic behaviour of physically nonlinear elastic cracked concrete beam-columns under pulsating axial force and constant lateral force is investigated. The constitutive equations derived earlier by Authors in the form of force-displacement relations are employed here to formulate equations of motion of the SDOF cantilever with mass lumped at its free end. The expected phenomenon of parametric resonance is exhibited in the form of regular subharmonic resonance at about the frequency ratio of two. Resonance peaks broaden with increase in pulsating force. Like damping, physical nonlinearity is also predicted to stabilize the dynamic response at resonance frequencies. In some particular statically unstable conditions, the loss of dynamic stability is shown to occur by divergence. Unexpectedly, similar phenomenon of parametric resonance is exhibited by these physically nonlinear beam-columns undergoing even small lateral displacements. The contribution made to the theory of parametric resonance and the potential relevance of the proposed theory to design of concrete beam-columns is discussed.

  5. Bioremediation of PAH polluted soils: column studies

    Energy Technology Data Exchange (ETDEWEB)

    Hallberg, R.O. [Dept. of Geology and Geochemistry, Stockholm Univ., Stockholm (Sweden); Trepte, B.S. [Angpannefoereningen AB, Stockholm (Sweden)


    Background. Due to spills, discharges and leakage, the gaswork site at Husarviken in Stockholm is today the largest (36 ha) creosote-contaminated site in Sweden. The main pollutants are creosote, lead and mercury. The remediation costs are estimated to be as high as US $125 million. It is thus of great interest to find more cost effective remediation methods. Objectives. The aim of this study was to investigate i) if the addition of NTA, EDTA, nitrate, iron and dry yeast would enhance the bioremediation rate of a complex organic pollutant like PAH and, if so, at what concentrations they would be most efficient, ii) the effect on PAH reduction when larger dimensions of the column is used to diminish the effect of water passing along the sides of the column, iii) long-term effects on the reduction of PAH in field-contaminated soil with high concentrations. Materials and Methods. Creosote-contaminated soil from the Husarviken gaswork site was treated with aerated water in column experiments at room temperature. Three column experiments were performed in 2 and 100 L of homogenised soil samples percolated by recirculating flushing water. Fluoranthene was analysed as a representative of the overall degradation of PAH in the columns. (orig.)

  6. Inert carriers for column extraction chromatography

    International Nuclear Information System (INIS)

    Katykhin, G.S.


    Inert carriers used in column extraction chromatography are reviewed. Such carriers are devided into two large groups: hydrophilic carriers which possess high surface energy and are well wetted only with strongly polar liquids (kieselguhrs, silica gels, glasses, cellulose, Al 2 O 3 ) and water-repellent carriers which possess low surface energy and are well wetted with various organic solvents (polyethylene, polytetrafluorethylene polytrifluorochlorethylene). Properties of various carriers are presented: structure, chemical and radiation stability, adsorption properties, extracting agent capacity. The effect of structure and sizes of particles on the efficiency of chromatography columns is considered. Ways of immovable phase deposition on the carrier and the latter's regeneration. Peculiarities of column packing for preparative and continuous chromatography are discussed

  7. Computational analysis of ozonation in bubble columns

    International Nuclear Information System (INIS)

    Quinones-Bolanos, E.; Zhou, H.; Otten, L.


    This paper presents a new computational ozonation model based on the principle of computational fluid dynamics along with the kinetics of ozone decay and microbial inactivation to predict the performance of ozone disinfection in fine bubble columns. The model can be represented using a mixture two-phase flow model to simulate the hydrodynamics of the water flow and using two transport equations to track the concentration profiles of ozone and microorganisms along the height of the column, respectively. The applicability of this model was then demonstrated by comparing the simulated ozone concentrations with experimental measurements obtained from a pilot scale fine bubble column. One distinct advantage of this approach is that it does not require the prerequisite assumptions such as plug flow condition, perfect mixing, tanks-in-series, uniform radial or longitudinal dispersion in predicting the performance of disinfection contactors without carrying out expensive and tedious tracer studies. (author)

  8. Flooding characteristics in pulsed packed extraction columns

    Directory of Open Access Journals (Sweden)

    M. Asadollahzadeh


    Full Text Available Flooding behavior of a 76.2 mm diameter pulsed packed column has been determined using four different liquid-liquid systems. The effects of pulsation intensity, flow ratio, interfacial tension, and packing geometry on flood point have been investigated. The results showed that the maximum throughput of the column decreases with an increase in pulsation intensity and flow ratio, while it increases with an increase in interfacial tension. The applicability of the characteristic velocity method to this type of column for the analysis of the flood point was examined and a marked deviation was observed between experimental results and values calculated by this method. Two new empirical correlations for flooding velocity and holdup at flooding are derived in terms of operating variables, packing characteristics, and physical properties of the liquid systems. Good agreement between prediction and experiments has been found for all operating conditions that were investigated.

  9. Mathematical modeling of alcohol distillation columns

    Directory of Open Access Journals (Sweden)

    Ones Osney Pérez


    Full Text Available New evaluation modules are proposed to extend the scope of a modular simulator oriented to the sugar cane industry, called STA 4.0, in a way that it can be used to carry out x calculation and analysis in ethanol distilleries. Calculation modules were developed for the simulation of the columns that are combined in the distillation area. Mathematical models were supported on materials and energy balances, equilibrium relations and thermodynamic properties of the ethanol-water system. Ponchon-Savarit method was used for the evaluation of the theoretical stages in the columns. A comparison between the results using Ponchon- Savarit method and those obtained applying McCabe-Thiele method was done for a distillation column. These calculation modules for ethanol distilleries were applied to a real case for validation.


    International Nuclear Information System (INIS)

    Gwyn, Stephen D. J.


    This paper describes the image stacks and catalogs of the Canada-France-Hawaii Telescope Legacy Survey produced using the MegaPipe data pipeline at the Canadian Astronomy Data Centre. The Legacy Survey is divided into two parts. The Deep Survey consists of four fields each of 1 deg 2 , with magnitude limits (50% completeness for point sources) of u = 27.5, g = 27.9, r = 27.7, i = 27.4, and z = 26.2. It contains 1.6 × 10 6 sources. The Wide Survey consists of 150 deg 2 split over four fields, with magnitude limits of u = 26.0, g = 26.5, r = 25.9, i = 25.7, and z = 24.6. It contains 3 × 10 7 sources. This paper describes the calibration, image stacking, and catalog generation process. The images and catalogs are available on the web through several interfaces: normal image and text file catalog downloads, a 'Google Sky' interface, an image cutout service, and a catalog database query service.

  11. Hydrothermal synthesis and photoluminescent properties of stacked indium sulfide superstructures. (United States)

    Xing, Yan; Zhang, Hongjie; Song, Shuyan; Feng, Jing; Lei, Yongqian; Zhao, Lijun; Li, Meiye


    Unusual hierarchical stacked superstructures of cubic beta-In2S3 were fabricated via a facile hydrothermal process in the presence of a surfactant cetyltrimethylammonium bromide CTAB; the 3D superstructures were developed by helical propagation of surface steps from microflakes of 10-20 nm thickness.

  12. Phase locked fluxon-antifluxon states in stacked Josephson junctions

    DEFF Research Database (Denmark)

    Carapella, Giovanni; Constabile, Giovanni; Petraglia, Antonio


    Measurements were made on a two-stack long Josephson junction with very similar parameters and electrical access to the thin middle electrode. Mutually phase-locked fluxon-antifluxon states were observed. The observed propagation velocity is in agreement with the theoretical prediction. The I-V c...... in the junctions coexist with fluxons. (C) 1996 American Institute of Physics....

  13. Compactifications of reductive groups as moduli stacks of bundles

    DEFF Research Database (Denmark)

    Martens, Johan; Thaddeus, Michael

    Let G be a reductive group. We introduce the moduli problem of "bundle chains" parametrizing framed principal G-bundles on chains of lines. Any fan supported in a Weyl chamber determines a stability condition on bundle chains. Its moduli stack provides an equivariant toroidal compactification of G...

  14. Stacking faults and microstructural parameters in non-mulberry silk ...

    Indian Academy of Sciences (India)

    Then the whole pattern fitting was done by introducing weight factors for the individual profiles and also taking into account the average stacking faults derived using eqs (4) and (5) in the final stage of refinement with the whole experimental diffraction data of the sample. Computational procedure is given in the flow chart ...

  15. Rhythmic ring–ring stacking drives the circadian oscillator clockwise (United States)

    Chang, Yong-Gang; Tseng, Roger; Kuo, Nai-Wei; LiWang, Andy


    The oscillator of the circadian clock of cyanobacteria is composed of three proteins, KaiA, KaiB, and KaiC, which together generate a self-sustained ∼24-h rhythm of phosphorylation of KaiC. The mechanism propelling this oscillator has remained elusive, however. We show that stacking interactions between the CI and CII rings of KaiC drive the transition from the phosphorylation-specific KaiC–KaiA interaction to the dephosphorylation-specific KaiC–KaiB interaction. We have identified the KaiB-binding site, which is on the CI domain. This site is hidden when CI domains are associated as a hexameric ring. However, stacking of the CI and CII rings exposes the KaiB-binding site. Because the clock output protein SasA also binds to CI and competes with KaiB for binding, ring stacking likely regulates clock output. We demonstrate that ADP can expose the KaiB-binding site in the absence of ring stacking, providing an explanation for how it can reset the clock. PMID:22967510

  16. Rhythmic ring-ring stacking drives the circadian oscillator clockwise. (United States)

    Chang, Yong-Gang; Tseng, Roger; Kuo, Nai-Wei; LiWang, Andy


    The oscillator of the circadian clock of cyanobacteria is composed of three proteins, KaiA, KaiB, and KaiC, which together generate a self-sustained ∼24-h rhythm of phosphorylation of KaiC. The mechanism propelling this oscillator has remained elusive, however. We show that stacking interactions between the CI and CII rings of KaiC drive the transition from the phosphorylation-specific KaiC-KaiA interaction to the dephosphorylation-specific KaiC-KaiB interaction. We have identified the KaiB-binding site, which is on the CI domain. This site is hidden when CI domains are associated as a hexameric ring. However, stacking of the CI and CII rings exposes the KaiB-binding site. Because the clock output protein SasA also binds to CI and competes with KaiB for binding, ring stacking likely regulates clock output. We demonstrate that ADP can expose the KaiB-binding site in the absence of ring stacking, providing an explanation for how it can reset the clock.

  17. Revisiting the Fundamentals and Capabilities of the Stack Compression Test

    DEFF Research Database (Denmark)

    Alves, L.M.; Nielsen, Chris Valentin; Martin, P.A.F.


    performance by comparing the flow curves obtained from its utilisation with those determined by means of compressive testing carried out on solid cylinder specimens of the same material. Results show that mechanical testing of materials by means of the stack compression test is capable of meeting...... the increasing demand of accurate and reliable flow curves for sheet metals....

  18. Stacked-Bloch-wave electron diffraction simulations using GPU acceleration

    International Nuclear Information System (INIS)

    Pennington, Robert S.; Wang, Feng; Koch, Christoph T.


    In this paper, we discuss the advantages for Bloch-wave simulations performed using graphics processing units (GPUs), based on approximating the matrix exponential directly instead of performing a matrix diagonalization. Our direct matrix-exponential algorithm yields a functionally identical electron scattering matrix to that generated with matrix diagonalization. Using the matrix-exponential scaling-and-squaring method with a Padé approximation, direct GPU-based matrix-exponential double-precision calculations are up to 20× faster than CPU-based calculations and up to approximately 70× faster than matrix diagonalization. We compare precision and runtime of scaling and squaring methods with either the Padé approximation or a Taylor expansion. We also discuss the stacked-Bloch-wave method, and show that our stacked-Bloch-wave implementation yields the same electron scattering matrix as traditional Bloch-wave matrix diagonalization. - Highlights: • Bloch-wave and stacked-Bloch-wave calculations can be accelerated with GPUs. • Direct approximation of the matrix exponential can be faster than diagonalization. • GPU-based direct approximation can be ≈70× faster than CPU diagonalization. • Larger matrices benefit more from this approach than smaller ones. • Stacked-Bloch-wave scattering results are functionally identical to diagonalization

  19. Do Identical Polar Diatomic Molecules Form Stacked or Linear ...

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 19; Issue 8. Do Identical Polar Diatomic Molecules Form Stacked or Linear Dimers?: Hydrogen Bonding is Not Just Dipole-Dipole Interactions. C W Williams Richard N Zare E Arunan. General Article Volume 19 Issue 8 August 2014 pp 704-712 ...

  20. 7. Data Structures: Lists, Queues, Stacks and Arrays

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 2; Issue 6. Algorithms - Data Structures: Lists, Queues, Stacks and Arrays. R K Shyamasundar ... Author Affiliations. R K Shyamasundar1. Computer Science Group, Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai 400 005, India ...

  1. Seismic fragility of ventilation stack of nuclear power plant

    International Nuclear Information System (INIS)

    Nefedov, S.S.; Yugai, T.Z.; Kalinkin, I.V.; Vizir, P.L.


    Fragility study of safety related elements is necessary step in seismic PSA of nuclear power plant (NPP). In present work fragility was analyzed after the example of the ventilation stack of NPP. Ventilation stack, considered in present work, is a separately erected construction with height of 100 m made of cast-in-place reinforced concrete. In accordance with IAEA terminology fragility of element is defined as conditional probability of its failure at given level of seismic loading. Failure of a ventilation stack was considered as development of the plastic hinge in some section of a shaft. Seismic ground acceleration a, which corresponds to failure, could be defined as limit seismic acceleration of ventilation stack [a]. Limit seismic acceleration [a] was considered as random value. Sources of its variation are connected with stochastic nature of factors determining it (properties of construction materials, soils etc.), and also with uncertainties of existing analytical techniques. Random value [a] was assumed to be distributed lognormally. Median m[a] and logarithmically standard deviation β of this distribution were defined by 'scaling method' developed by R.P. Kennedy et al. Using this values fragility curves were plotted for different levels of confidence probability. (author)

  2. Thermal entrance effects in a thermoacoustic stacked screen regenerator

    NARCIS (Netherlands)

    Bühler, Simon; wilcox, D; Oosterhuis, Joris; van der Meer, Theodorus H.


    Thermoacoustic cryocoolers are of raising interest because they are cost effective and reliable. The underlying heat pumping process occurs in the regenerator, where a sound wave interacts with a solid matrix material. Stacked screens are frequently used to build regenerators for thermoacoustic

  3. Proposal of stack Effect technology for predicted future years (United States)

    Teddy Badai Samodra, FX; Adi Indrawan, Iwan


    Recently, stack effect is a general problem solver in providing vertical ventilation for urban environmental issues. However, study on resilient technology of stack effect for future years as predicted by climate trend should be conducted. Therefore, this research proposes a design of new technology on operable and adaptable vertical ventilation to the environmental change. The research method is conducted by comprehensive simulation of Ecotect Analysis, ANSYS Fluent and Matlab. Urban environment of Surabaya, as the research location, is the representative of tropical region. The results showed that the stack effect height and area could be modified instantly adjusting the environmental condition time by time in the future years. With 1.8 m of stack width, the proposed technology could capture 40 m3 of vertical air flow which is useful for physiological cooling and its dimension could be modified depending on the environmental condition. By providing resilient technology, predictable and sustainable ventilation method is offered to anticipate an unpredicted global warming and environmental change.

  4. Multipole stack for the 4 rings of the PS Booster

    CERN Multimedia

    CERN PhotoLab


    The PS Booster (originally 800 MeV, now 1.4 GeV) saw first beam in 1972, routine operation began in 1973. The strive for ever higher intensities required the addition of multipoles. Manufacture of 8 stacks of multipoles was launched in 1974, for installation in 1976. For details, see 7511120X.

  5. Consolidation process model for film stacking glass/PPS laminates

    NARCIS (Netherlands)

    Grouve, Wouter Johannes Bernardus; Akkerman, Remko


    A model is proposed to optimise the processing parameters for the consolidation of glass/polyphenylene sulphide (PPS) laminates using a film stacking procedure. In a split approach, the heating and consolidation phase are treated separately. The heating phase is modelled using the one-dimensional

  6. 7. Data Structures: Lists, Queues, Stacks and Arrays

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 2; Issue 6. Algorithms - Data Structures: Lists, Queues, Stacks and Arrays. R K Shyamasundar. Series Article Volume 2 Issue 6 June 1997 pp 39-46. Fulltext. Click here to view fulltext PDF. Permanent link:

  7. Calculating the output distribution of stack filters that are erosion ...

    African Journals Online (AJOL)

    Two procedures to compute the output distribution ϕs of certain stack filters S (so called erosion-dilation cascades) are given. One rests on the disjunctive normal form of S and also yields the rank selection probabilities. The other is based on inclusion-exclusion and e.g. yields ϕs for some important LULU-operators S.

  8. Precise stacking and bonding technology for RDDS structure

    International Nuclear Information System (INIS)

    Higo, T; Toge, N.; Suzuki, T.


    The X-band accelerating structures called RDDS1 (Rounded Dumped Detuned Structure) for the linear collider have been developed. The main body of RDDS1 was successfully fabricated in Japan (KEK, IHI). We established basic fabrication techniques through the development of prototype structures including RDDS1. The precise stacking and bonding technologies for RDDS structure are presented in this paper. (author)

  9. Operation of the annular pulsed column, (2)

    International Nuclear Information System (INIS)

    Takahashi, Keiki; Tsukada, Takeshi


    The heat of reaction generated form the uranium extraction is considered to from the temperature profile inside the pulsed column. A simulation code was developed to estimate the temperature profile, considering heat generation and counter-current heat transfer. The temperature profiles calculated using this code was found to depend on both the position of the extraction zone and the operating condition. The reported experimental result was fairly represented by this simulation code. We consider that this presented simulation code is capable of providing with the temperature profile in the pulsed column and useful for the monitoring of the uranium extraction zone. (author)

  10. Distillation columns inspection through gamma scanning

    International Nuclear Information System (INIS)

    Garcia, Marco


    The application of nuclear energy is very wide and it allows the saving of economic resources since the investigation of a certain process is carried out without stop the plant. The gamma scanning of oil c racking c olumns are practical examples, they allow to determine the hydraulic operation of the inspected columns. A source of Co-60 22mCi and a detector with a crystal of INa(TI) are used. This paper shows the results got from a profile carried out in a column distillation

  11. Performance of RC columns with partial length corrosion

    International Nuclear Information System (INIS)

    Wang Xiaohui; Liang Fayun


    Experimental and analytical studies on the load capacity of reinforced concrete (RC) columns with partial length corrosion are presented, where only a fraction of the column length was corroded. Twelve simply supported columns were eccentrically loaded. The primary variables were partial length corrosion in tensile or compressive zone and the corrosion level within this length. The failure of the corroded column occurs in the partial length, mainly developed from or located nearby or merged with the longitudinal corrosion cracks. For RC column with large eccentricity, load capacity of the column is mainly influenced by the partial length corrosion in tensile zone; while for RC column with small eccentricity, load capacity of the column greatly decreases due to the partial length corrosion in compressive zone. The destruction of the longitudinally mechanical integrality of the column in the partial length leads to this great reduction of the load capacity of the RC column

  12. Development and Applications of a Stage Stacking Procedure (United States)

    Kulkarni, Sameer; Celestina, Mark L.; Adamczyk, John J.


    The preliminary design of multistage axial compressors in gas turbine engines is typically accomplished with mean-line methods. These methods, which rely on empirical correlations, estimate compressor performance well near the design point, but may become less reliable off-design. For land-based applications of gas turbine engines, off-design performance estimates are becoming increasingly important, as turbine plant operators desire peaking or load-following capabilities and hot-day operability. The current work develops a one-dimensional stage stacking procedure, including a newly defined blockage term, which is used to estimate the off-design performance and operability range of a 13-stage axial compressor used in a power generating gas turbine engine. The new blockage term is defined to give mathematical closure on static pressure, and values of blockage are shown to collapse to curves as a function of stage inlet flow coefficient and corrected shaft speed. In addition to these blockage curves, the stage stacking procedure utilizes stage characteristics of ideal work coefficient and adiabatic efficiency. These curves are constructed using flow information extracted from computational fluid dynamics (CFD) simulations of groups of stages within the compressor. Performance estimates resulting from the stage stacking procedure are shown to match the results of CFD simulations of the entire compressor to within 1.6% in overall total pressure ratio and within 0.3 points in overall adiabatic efficiency. Utility of the stage stacking procedure is demonstrated by estimation of the minimum corrected speed which allows stable operation of the compressor. Further utility of the stage stacking procedure is demonstrated with a bleed sensitivity study, which estimates a bleed schedule to expand the compressors operating range.

  13. Hydrodynamic Modelling and Experimental Analysis of FE-DMFC Stacks (United States)

    Kablou, Yashar

    Direct methanol fuel cells (DMFCs) present some unique features such as having liquid fuel, quick refueling process, compact design and high energy density. These characteristics make them incredibly suitable as a promising power source for portable electronic applications, such as cell phones or laptop computers. Despite of these positive aspects, the commercial development of DMFCs has nevertheless been hindered by some important issues such as, carbon dioxide formation at the anode compartment and, methanol crossover through the membrane. Many researchers have tried to model the two-phase flow behavior inside the DMFC anode compartment using the "homogenous flow modelling" approach, which has proven to be inaccurate specially when dealing with DMFC stacks. On the other hand, several strategies to prevent methanol crossover have been suggested in the literature, including the use of a flowing electrolyte between the DMFC anode and cathode compartments. Preliminary tests on flowing electrolyte direct methanol fuel cells (FE-DMFCs) have shown promising results; however, further investigation should be carried out on the stack level. In the first part of this study, a quasi two-dimensional numerical model was developed, to predict the two-phase flow behavior within the DMFC anode compartment, both in single cell and stack levels. Various types of flow modelling approaches and void fraction correlations were utilized to estimate the pressure drop across the anode compartment. It was found that the "separated flow modelling" approach, as well as CISE correlation for void fraction (developed at the CISE labs in Milan), yield the best results. In the second part, a five-cell FE-DMFC stack unit with a parallel serpentine flow bed design and U-type manifold configuration, was developed and tested at various operating conditions. It was found that, the flowing electrolyte effectively reduced methanol crossover and, improved the stack performance.

  14. Do Stacked Species Distribution Models Reflect Altitudinal Diversity Patterns? (United States)

    Mateo, Rubén G.; Felicísimo, Ángel M.; Pottier, Julien; Guisan, Antoine; Muñoz, Jesús


    The objective of this study was to evaluate the performance of stacked species distribution models in predicting the alpha and gamma species diversity patterns of two important plant clades along elevation in the Andes. We modelled the distribution of the species in the Anthurium genus (53 species) and the Bromeliaceae family (89 species) using six modelling techniques. We combined all of the predictions for the same species in ensemble models based on two different criteria: the average of the rescaled predictions by all techniques and the average of the best techniques. The rescaled predictions were then reclassified into binary predictions (presence/absence). By stacking either the original predictions or binary predictions for both ensemble procedures, we obtained four different species richness models per taxa. The gamma and alpha diversity per elevation band (500 m) was also computed. To evaluate the prediction abilities for the four predictions of species richness and gamma diversity, the models were compared with the real data along an elevation gradient that was independently compiled by specialists. Finally, we also tested whether our richness models performed better than a null model of altitudinal changes of diversity based on the literature. Stacking of the ensemble prediction of the individual species models generated richness models that proved to be well correlated with the observed alpha diversity richness patterns along elevation and with the gamma diversity derived from the literature. Overall, these models tend to overpredict species richness. The use of the ensemble predictions from the species models built with different techniques seems very promising for modelling of species assemblages. Stacking of the binary models reduced the over-prediction, although more research is needed. The randomisation test proved to be a promising method for testing the performance of the stacked models, but other implementations may still be developed. PMID

  15. Scalability of pre-packed preparative chromatography columns with different diameters and lengths taking into account extra column effects. (United States)

    Schweiger, Susanne; Jungbauer, Alois


    Small pre-packed columns are commonly used to estimate the optimum run parameters for pilot and production scale. The question arises if the experiments obtained with these columns are scalable, because there are substantial changes in extra column volume when going from a very small scale to a benchtop column. In this study we demonstrate the scalability of pre-packed disposable and non-disposable columns of volumes in the range of 0.2-20 ml packed with various media using superficial velocities in the range of 30-500 cm/h. We found that the relative contribution of extra column band broadening to total band broadening was not only high for columns with small diameters, but also for columns with a larger volume due to their wider diameter. The extra column band broadening can be more than 50% for columns with volumes larger than 10 ml. An increase in column diameter leads to high additional extra column band broadening in the filter, frits, and adapters of the columns. We found a linear relationship between intra column band broadening and column length, which increased stepwise with increases in column diameter. This effect was also corroborated by CFD simulation. The intra column band broadening was the same for columns packed with different media. An empirical engineering equation and the data gained from the extra column effects allowed us to predict the intra, extra, and total column band broadening just from column length, diameter, and flow rate. Copyright © 2018 The Author(s). Published by Elsevier B.V. All rights reserved.

  16. Convolutional Codes with Maximum Column Sum Rank for Network Streaming


    Mahmood, Rafid; Badr, Ahmed; Khisti, Ashish


    The column Hamming distance of a convolutional code determines the error correction capability when streaming over a class of packet erasure channels. We introduce a metric known as the column sum rank, that parallels column Hamming distance when streaming over a network with link failures. We prove rank analogues of several known column Hamming distance properties and introduce a new family of convolutional codes that maximize the column sum rank up to the code memory. Our construction invol...

  17. Optimization and simulation of tandem column supercritical fluid chromatography separations using column back pressure as a unique parameter. (United States)

    Wang, Chunlei; Tymiak, Adrienne A; Zhang, Yingru


    Tandem column supercritical fluid chromatography (SFC) has demonstrated to be a useful technique to resolve complex mixtures by serially coupling two columns of different selectivity. The overall selectivity of a tandem column separation is the retention time weighted average of selectivity from each coupled column. Currently, the method development merely relies on extensive screenings and is often a hit-or-miss process. No attention is paid to independently adjust retention and selectivity contributions from individual columns. In this study, we show how tandem column SFC selectivity can be optimized by changing relative dimensions (length or inner diameter) of the coupled columns. Moreover, we apply column back pressure as a unique parameter for SFC optimization. Continuous tuning of tandem column SFC selectivity is illustrated through column back pressure adjustments of the upstream column, for the first time. In addition, we show how and why changing coupling order of the columns can produce dramatically different separations. Using the empirical mathematical equation derived in our previous study, we also demonstrate a simulation of tandem column separations based on a single retention time measurement on each column. The simulation compares well with experimental results and correctly predicts column order and back pressure effects on the separations. Finally, considerations on instrument and column hardware requirements are discussed.

  18. Influence of pressure on the properties of chromatographic columns. II. The column hold-up volume. (United States)

    Gritti, Fabrice; Martin, Michel; Guiochon, Georges


    The effect of the local pressure and of the average column pressure on the hold-up column volume was investigated between 1 and 400 bar, from a theoretical and an experimental point of view. Calculations based upon the elasticity of the solids involved (column wall and packing material) and the compressibility of the liquid phase show that the increase of the column hold-up volume with increasing pressure that is observed is correlated with (in order of decreasing importance): (1) the compressibility of the mobile phase (+1 to 5%); (2) in RPLC, the compressibility of the C18-bonded layer on the surface of the silica (+0.5 to 1%); and (3) the expansion of the column tube (columns packed with the pure Resolve silica (0% carbon), the derivatized Resolve-C18 (10% carbon) and the Symmetry-C18 (20% carbon) adsorbents, using water, methanol, or n-pentane as the mobile phase. These solvents have different compressibilities. However, 1% of the relative increase of the column hold-up volume that was observed when the pressure was raised is not accounted for by the compressibilities of either the solvent or the C18-bonded phase. It is due to the influence of the pressure on the retention behavior of thiourea, the compound used as tracer to measure the hold-up volume.

  19. Reducing the overlay metrology sensitivity to perturbations of the measurement stack (United States)

    Zhou, Yue; Park, DeNeil; Gutjahr, Karsten; Gottipati, Abhishek; Vuong, Tam; Bae, Sung Yong; Stokes, Nicholas; Jiang, Aiqin; Hsu, Po Ya; O'Mahony, Mark; Donini, Andrea; Visser, Bart; de Ruiter, Chris; Grzela, Grzegorz; van der Laan, Hans; Jak, Martin; Izikson, Pavel; Morgan, Stephen


    Overlay metrology setup today faces a continuously changing landscape of process steps. During Diffraction Based Overlay (DBO) metrology setup, many different metrology target designs are evaluated in order to cover the full process window. The standard method for overlay metrology setup consists of single-wafer optimization in which the performance of all available metrology targets is evaluated. Without the availability of external reference data or multiwafer measurements it is hard to predict the metrology accuracy and robustness against process variations which naturally occur from wafer-to-wafer and lot-to-lot. In this paper, the capabilities of the Holistic Metrology Qualification (HMQ) setup flow are outlined, in particular with respect to overlay metrology accuracy and process robustness. The significance of robustness and its impact on overlay measurements is discussed using multiple examples. Measurement differences caused by slight stack variations across the target area, called grating imbalance, are shown to cause significant errors in the overlay calculation in case the recipe and target have not been selected properly. To this point, an overlay sensitivity check on perturbations of the measurement stack is presented for improvement of the overlay metrology setup flow. An extensive analysis on Key Performance Indicators (KPIs) from HMQ recipe optimization is performed on µDBO measurements of product wafers. The key parameters describing the sensitivity to perturbations of the measurement stack are based on an intra-target analysis. Using advanced image analysis, which is only possible for image plane detection of μDBO instead of pupil plane detection of DBO, the process robustness performance of a recipe can be determined. Intra-target analysis can be applied for a wide range of applications, independent of layers and devices.

  20. Development of a New Radiation Measuring Instrument for the Column Scanning Technique - NibraS

    International Nuclear Information System (INIS)

    Benahmed, A.; Alami, R.


    The radiation measuring instrument, called Nibras, associated to a special data processing software for Column scanning is a new data acquisition system. It was developed to scan and to plot density profiles, inside a distillation column, which illustrates the activity of the radiations able to cross the contents of the column. Nibras is an autonomous data logger with very low power consumption, using only 4 batteries of 1.5 V and can be operated for more than 120 hours continuously; this presents an ecological and economic importance. Another particularity of Nibras consists in its dual functionality to display counting rates indicating the existence and the intensity of radiation; and to perform a real-time control in industrial plant particularly in oil distillation columns, due to its user-friendly software. This last provides essential data to optimize the performance of the columns, extend column run times, track the performance-deteriorating effects of fouling and solids deposition, and to identify maintenance requirements well in advance of scheduled turnarounds. This on-line knowledge can reduce repair downtime significantly. (authors)

  1. On Row Rank Equal Column Rank (United States)

    Khalili, Parviz


    We will prove a well-known theorem in Linear Algebra, that is, for any "m x n" matrix the dimension of row space and column space are the same. The proof is based on the subject of "elementary matrices" and "reduced row-echelon" form of a matrix.

  2. On Stability of a Bubble Column

    Czech Academy of Sciences Publication Activity Database

    Růžička, Marek


    Roč. 91, č. 2 (2013), s. 191-203 ISSN 0263-8762 R&D Projects: GA ČR GA104/07/1110 Institutional support: RVO:67985858 Keywords : bubble column * flow regimes * steady solution Subject RIV: CI - Industrial Chemistry, Chemical Engineering Impact factor: 2.281, year: 2013

  3. Flexural buckling of fire exposed aluminium columns

    NARCIS (Netherlands)

    Maljaars, J.; Twilt, L.; Soetens, F.


    In order to study buckling of fire exposed aluminium columns, a finite element model is developed. The results of this model are verified with experiments. Based on a parametric study with the finite element model, it is concluded that the simple calculation model for flexural buckling of fire

  4. Chief Editor's column/Science Smiles

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 1; Issue 4. Chief Editor's column / Science Smiles. R K Laxman. Science Smiles Volume 1 Issue 4 April 1996 pp 4-4. Fulltext. Click here to view fulltext PDF. Permanent link: Author Affiliations.

  5. Column Stores as an IR Prototyping Tool

    NARCIS (Netherlands)

    H.F. Mühleisen (Hannes); T. Samar (Thaer); J.J.P. Lin (Jimmy); A.P. de Vries (Arjen)


    textabstract. We make the suggestion that instead of implementing custom index structures and query evaluation algorithms, IR researchers should simply store document representations in a column-oriented relational database and write ranking models using SQL. For rapid prototyping, this is

  6. Robust Geometric Control of a Distillation Column

    DEFF Research Database (Denmark)

    Kymmel, Mogens; Andersen, Henrik Weisberg


    A frequency domain method, which makes it possible to adjust multivariable controllers with respect to both nominal performance and robustness, is presented. The basic idea in the approach is that the designer assigns objectives such as steady-state tracking, maximum resonance peaks, bandwidth, m...... is used to examine and improve geometric control of a binary distillation column....

  7. Yield stress independent column buckling curves

    DEFF Research Database (Denmark)

    Stan, Tudor‐Cristian; Jönsson, Jeppe


    Using GMNIA and shell finite element modelling of steel columns it is ascertained that the buckling curves for given imperfections and residual stresses are not only dependent on the relative slenderness ratio and the cross section shape but also on the magnitude of the yield stress. The influence...

  8. "Dry-column" chromatography of plant pigments (United States)

    Woeller, F. H.; Lehwalt, M. F.; Oyama, V. I.


    Separation of plant pigments which can be accomplished on thin-layer silica plates with mixture of petroleum ether, halocarbon, acetone, and polar solvent can be readily translated into dry-column technique that yields reproducible chromatograms after elution in fashion of liquid chromatography with fluorimeter as detector. Best solvent system was found to be mixture of petroleum ether, dichloromethane, acetone, and ethyl acetate.

  9. Seismic Behaviour of Synthetic-Frc Columns (United States)

    Paultre, P.; Eid, R.


    Inclusion of short discrete fibres into the concrete mixture can increase the compressive strength and ductility of normal-strength concrete (NSC) and high-strength concrete (HSC) column specimens under compressive loading as already has been shown by several studies. Concrete design codes ensure ductile behaviour of columns by setting a requirement for a minimum amount of transverse steel reinforcement. Therefore, the inclusion of discrete short fibres into the concrete mixture combined with a reduced amount of lateral reinforcement can be an alternative to the latter full amount required by the codes. This paper presents tests that were performed on large-scale fibre-reinforced NSC circular columns under cyclic flexure and constant axial load simulating earthquake loading. The aim of this test program is to examine the combined confinement effect of steel or synthetic fibres and the transverse steel reinforcement type (spirals or hoops) on the structural performance of RC columns. The results show that in terms of ductility and energy dissipation, the behaviour of the fibre-reinforced concrete (FRC) specimens is improved compared to the nonfibrous ones. This behaviour is also predicted by the proposed confinement model which takes into account the mechanical and the geometrical properties of the concrete and the reinforcement as well as those of the fibres.

  10. Contexts for Column Addition and Subtraction (United States)

    Lopez Fernandez, Jorge M.; Velazquez Estrella, Aileen


    In this article, the authors discuss their approach to column addition and subtraction algorithms. Adapting an original idea of Paul Cobb and Erna Yackel's from "A Contextual Investigation of Three-Digit Addition and Subtraction" related to packing and unpacking candy in a candy factory, the authors provided an analogous context by…

  11. The hydrodynamic behaviour of a pulsed column

    International Nuclear Information System (INIS)

    Vassallo, Gary.


    Holdup, droplet size and continuous-phase backmixing were measured in a 72 mm i.d. pulsed perforated-plate column. The contactor was operated using the system 2 M HNO 3 -30% TBP/OP. Pulse amplitude, frequency and both phase flow rates were varied over a wide range of values although the column was maintained in the continuous dispersion region. Dispersed-phase holdup appeared to pass through a minimum at a constant pulse velocity corresponding to the onset of continuous dispersion type operation. The value of this minimum varied linearly with the dispersed-phase flow rate. Measurements of holdup were correlated using the slip velocity concept, modified to allow for droplet coalescence. Values of the Sauter-mean droplet diameter were found to vary with the pulse velocity and holdup. It was shown that the ratio of the characteristic droplet velocity in a pulsed perforated-plate column to that in a spray column as derived from the correlation of Hu and Kintner is a function of the pulse velocity and holdup. This led to an expression which correlated the droplet size data with negligible error. Continuous-phase back mixing was found to increase with amplitude; frequency and dispersed-phase flow rate. The effect of the continuous-phase flow rate was variable. At low values, increasing the phase velocity reduced back mixing while at high values, an increase in the phase velocity had the reverse effect

  12. Single column and two-column H-D-T distillation experiments at TSTA

    International Nuclear Information System (INIS)

    Yamanishi, T.; Yoshida, H.; Hirata, S.; Naito, T.; Naruse, Y.; Sherman, R.H.; Bartlit, J.R.; Anderson, J.L.


    Cryogenic distillation experiments were peformed at TSTA with H-D-T system by using a single column and a two-column cascade. In the single column experiment, fundamental engineering data such as the liquid holdup and the HETP were measured under a variety of operational condtions. The liquid holdup in the packed section was about 10 /approximately/ 15% of its superficial volume. The HETP values were from 4 to 6 cm, and increased slightly with the vapor velocity. The reflux ratio had no effect on the HETP. For the wo-colunn experiemnt, dynamic behavior of the cascade was observed. 8 refs., 7 figs., 2 tabs

  13. RDX degradation in bioaugmented model aquifer columns under aerobic and low oxygen conditions. (United States)

    Fuller, Mark E; Hatzinger, Paul B; Condee, Charles W; Andaya, Christina; Rezes, Rachel; Michalsen, Mandy M; Crocker, Fiona H; Indest, Karl J; Jung, Carina M; Alon Blakeney, G; Istok, Jonathan D; Hammett, Steven A


    Degradation of hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) in laboratory columns following biostimulation and bioaugmentation was investigated using sediment and groundwater from a contaminated aquifer at a US Navy facility. No RDX degradation was observed following aerobic biostimulation with either fructose or lactate (both 0.1 mM) prior to bioaugmentation. Replicate columns were then bioaugmented with either Gordonia sp. KTR9, Pseudomonas fluorescens I-C (Ps I-C), or both strains. Under aerobic conditions (influent dissolved oxygen (DO) >6 mg/L), RDX was degraded following the addition of fructose, and to a lesser extent with lactate, in columns bioaugmented with KTR9. No degradation was observed in columns bioaugmented with only Ps I-C under aerobic conditions, consistent with the known anaerobic RDX degradation pathway for this strain. When influent DO was reduced to column, and some degradation was also observed in the Ps I-C-bioaugmented column. After DO levels were kept below 1 mg/L for more than a month, columns bioaugmented with KTR9 became unresponsive to fructose addition, while RDX degradation was still observed in the Ps I-C-bioaugmented columns. These results indicate that bioaugmentation with the aerobic RDX degrader KTR9 could be effective at sites where site geology or geochemistry allow higher DO levels to be maintained. Further, inclusion of strains capable of anoxic RDX degradation such as Ps I-C may facilitate bimodal RDX removal when DO levels decrease.

  14. Scale-up protein separation on stainless steel wide bore toroidal columns in the type-J counter-current chromatography. (United States)

    Guan, Yue Hugh; Hewitson, Peter; van den Heuvel, Remco N A M; Zhao, Yan; Siebers, Rick P G; Zhuang, Ying-Ping; Sutherland, Ian


    Manufacturing high-value added biotech biopharmaceutical products (e.g. therapeutic proteins) requires quick-to-develop, GMP-compliant, easy-to-scale and cost effective preparatory chromatography technologies. In this work, we describe the construction and testing of a set of 5-mm inner diameter stainless steel toroidal columns for use on commercially available preparatory scale synchronous J-type counter-current chromatography (CCC) machinery. We used a 20.2m long column with an aqueous two-phase system containing 14% (w/w) PEG1000 and 14% (w/w) potassium phosphate at pH 7, and tested a sample loading of 5% column volume and a mobile phase flow rate of 20ml/min. We then satisfactorily demonstrated the potential for a weekly protein separation and preparation throughput of ca. 11g based on a normal weekly routine for separating a pair of model proteins by making five stacked injections on a single portion of stationary phase with no stripping. Compared to our previous 1.6mm bore PTFE toroidal column, the present columns enlarged the nominal column processing throughput by nearly 10. For an ideal model protein injection modality, we observed a scaling up factor of at least 21. The 2 scales of protein separation and purification steps were realized on the same commercial CCC device. Copyright © 2015 Elsevier B.V. All rights reserved.

  15. Development of a sealed source radiation detector system for gamma ray scanning of petroleum distillation columns

    International Nuclear Information System (INIS)

    Vasquez Salvador, Pablo Antonio


    Gamma Ray Scanning is an online technique to 'view' the hydraulic performance of an operating column, with no disruption to operating processes conditions (pressure and temperature), as a cost-effective solution. The principle of this methodology consists of a small suitably sealed gamma radiation source and a radiation detector experimentally positioned to the column, moving concurrently in small increments on opposite sides and the quantity of gamma transmitted. The source-detector system consists of: a sealed ''6 0 Co radioactive source in a panoramic lead radiator, a scintillator detector coupled to a ratemeter / analyzer and a mobile system. In this work, a gamma scanning sealed source-detector system for distillation columns, was developed, comparing two scintillator detectors: NaI(Tl) (commercial) and CsI(Tl) (IPEN). In order to project the system, a simulated model of a tray-type distillation column was used. The equipment developed was tested in an industrial column for water treatment (6.5 m diameter and 40 m height). The required activities of 6 ''0Co, laboratory (11.1 MBq) and industrial works (1.48 TBq) were calculated by simulation software. Both, the NaI(Tl) and the CsI(Tl) detectors showed good proprieties for gamma scanning applications, determining the position and presence or absence of trays. (author)

  16. Plasma Processes: A self-consistent kinetic modeling of a 1-D ...

    Indian Academy of Sciences (India)

    A self-consistent kinetic treatment is presented here, where the Boltzmann equation is solved for a particle conserving Krook collision operator. The resulting equations have been implemented numerically. The treatment solves for the entire quasineutral column, making no assumptions about mfp/, where mfp is the ...

  17. Investigation of Ruthenium Dissolution in Advanced Membrane Electrode Assemblies for Direct Methanol Based Fuel Cells Stacks (United States)

    Valdez, T. I.; Firdosy, S.; Koel, B. E.; Narayanan, S. R.


    This viewgraph presentation gives a detailed review of the Direct Methanol Based Fuel Cell (DMFC) stack and investigates the Ruthenium that was found at the exit of the stack. The topics include: 1) Motivation; 2) Pathways for Cell Degradation; 3) Cell Duration Testing; 4) Duration Testing, MEA Analysis; and 5) Stack Degradation Analysis.

  18. The Methods of Design and Implementation of Stack Filters for Image Processing

    Directory of Open Access Journals (Sweden)

    S. Marchevsky


    Full Text Available This paper deals with a large class of nonlinear digital filters, the stack filters, which contain all combinations and compositions of rank order operators within a finite window. Attention is given to design and effective hardware implementation of an optimal stack filter for image processing. Presented simulation results confirm robustness of stack filters in the image restoration corrupted by impulsive noise.

  19. The Effect of a Sport Stacking Intervention on Handwriting with Second Grade Students (United States)

    Li, Yuhua; Coleman, Diane; Ransdell, Mary; Coleman, Lyndsie; Irwin, Carol


    The present study examined the impact a 14-week sport stacking (cup stacking) exercise intervention would have on children's handwriting quality and speed. Eighty-three second graders were randomly assigned to either an experimental or a control group. The experimental group (n = 42) participated in a 15-min session of sport stacking activities…

  20. Modelling and Evaluation of Heating Strategies for High Temperature Polymer Electrolyte Membrane Fuel Cell Stacks

    DEFF Research Database (Denmark)

    Andreasen, Søren Juhl; Kær, Søren Knudsen


    Experiments were conducted on two different cathode air cooled high temperature PEM (HTPEM) fuel cell stacks; a 30 cell 400W prototype stack using two bipolar plates per cell, and a 65 cell 1 kW commercial stack using one bipolar plate per cell. The work seeks to examine the use of different...