Contemporary sample stacking in analytical electrophoresis.

PubMed

Malá, Zdena; Gebauer, Petr; Boček, Petr

2011-01-01

Sample stacking is of vital importance for analytical CE since it may bring the required sensitivity of analyses. A lot of new relevant papers are published every year and regular surveys seem to be very helpful for experts and practitioners. The contribution presented here is a continuation of a series of regularly published reviews on the topic and covers the last two years. It brings a survey of related literature organized, in accord with the main principle used in the procedure published, in the following mainstream sections: Kohlrausch adjustment of concentrations, pH step, micellar systems and combined techniques. Each part covers literature sorted according to the field of application as, e.g. clinical, pharmaceutical, food, environmental, etc. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Acupuncture injection for field amplified sample stacking and glass microchip-based capillary gel electrophoresis.

PubMed

Ha, Ji Won; Hahn, Jong Hoon

2017-02-01

Acupuncture sample injection is a simple method to deliver well-defined nanoliter-scale sample plugs in PDMS microfluidic channels. This acupuncture injection method in microchip CE has several advantages, including minimization of sample consumption, the capability of serial injections of different sample solutions into the same microchannel, and the capability of injecting sample plugs into any desired position of a microchannel. Herein, we demonstrate that the simple and cost-effective acupuncture sample injection method can be used for PDMS microchip-based field amplified sample stacking in the most simplified straight channel by applying a single potential. We achieved the increase in electropherogram signals for the case of sample stacking. Furthermore, we present that microchip CGE of ΦX174 DNA-HaeⅢ digest can be performed with the acupuncture injection method on a glass microchip while minimizing sample loss and voltage control hardware. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Comparative study on sample stacking by moving reaction boundary formed with weak acid and weak or strong base in capillary electrophoresis: II. Experiments.

PubMed

Zhang, Wei; Fan, Liuyin; Shao, Jing; Li, Si; Li, Shan; Cao, Chengxi

2011-04-15

To demonstrate the theoretic method on the stacking of zwitterion with moving reaction boundary (MRB) in the accompanying paper, the relevant experiments were performed. The experimental results quantitatively show that (1) MRB velocity, including the comparisons between MRB and zwitterionic velocities, possesses key importance to the design of MRB stacking; (2) a much long front alkaline plug without sample should be injected before the sample injection for a complete stacking of zwitterion if sample buffer is prepared with strong base, conversely no such plug is needed if using a weak base as the sample buffer with proper concentration and pH value; (3) the presence of salt in MRB system holds dramatic effect on the MRB stacking if sample solution is a strong base, but has no effect if a weak alkali is used as sample solution; (4) all of the experiments of this paper, including the previous work, quantitatively manifest the theory and predictions shown in the accompanying paper. In addition, the so-called derivative MRB-induced re-stacking and transient FASI-induced re-stacking were also observed during the experiments, and the relevant mechanisms were briefly demonstrated with the results. The theory and its calculation procedures developed in the accompanying paper can be well used for the predictions to the MRB stacking of zwitterion in CE. Copyright © 2011 Elsevier B.V. All rights reserved.

40 CFR 141.703 - Sampling locations.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 23 2011-07-01 2011-07-01 false Sampling locations. 141.703 Section... Monitoring Requirements § 141.703 Sampling locations. (a) Systems required to conduct source water monitoring... a sampling tap is available where the sources are combined prior to treatment, systems must collect...

Visual offline sample stacking via moving neutralization boundary electrophoresis for analysis of heavy metal ion.

PubMed

Fan, Yinping; Li, Shan; Fan, Liuyin; Cao, Chengxi

2012-06-15

In this paper, a moving neutralization boundary (MNB) electrophoresis is developed as a novel model of visual offline sample stacking for the trace analysis of heavy metal ions (HMIs). In the stacking system, the cathodic-direction motion MNB is designed with 1.95-2.8mM HCl+98 mM KCl in phase alfa and 4.0mM NaOH+96 mM KCl in phase beta. If a little of HMI is present in phase alfa, the metal ion electrically migrates towards the MNB and react with hydroxyl ion, producing precipitation and moving precipitation boundary (MPB). The alkaline precipitation is neutralized by hydrogen ion, leading to a moving eluting boundary (MEB), release of HMI from its precipitation, circle of HMI from the MEB to the MPB, and highly efficient visual stacking. As a proof of concept, a set of metal ions (Cu(II), Co(II), Mn(II), Pb(II) and Cr(III)) were chosen as the model HMIs and capillary electrophoresis (CE) was selected as an analytical tool for the experiments demonstrating the feasibility of MNB-based stacking. As shown in this paper, (i) the visual stacking model was manifested by the experiments; (ii) there was a controllable stacking of HMI in the MNB system; (iii) the offline stacking could achieve higher than 123 fold preconcentration; and (iv) the five HMIs were simultaneously stacked via the developed stacking technique for the trace analyses with the limits of detection (LOD): 3.67×10(-3) (Cu(II)), 1.67×10(-3) (Co(II), 4.17×10(-3) (Mn(II)), 4.6×10(-4) (Pb(II)) and 8.40×10(-4)mM (Cr(III)). Even the off-line stacking was demonstrated for the use of CE-based HMI analysis, it has potential applications in atomic absorption spectroscopy (AAS), inductively coupled plasma-mass spectrometry (ICP-MS) and ion chromatography (IC) etc. Copyright © 2012 Elsevier B.V. All rights reserved.

Anionic microemulsion to solvent stacking for on-line sample concentration of cationic analytes in capillary electrophoresis.

PubMed

Kukusamude, Chunyapuk; Srijaranai, Supalax; Quirino, Joselito P

2014-05-01

The common SDS microemulsion (i.e. 3.3% SDS, 0.8% octane, and 6.6% butanol) and organic solvents were investigated for the stacking of cationic drugs in capillary zone electrophoresis using a low pH separation electrolyte. The sample was prepared in the acidic microemulsion and a high percentage of organic solvent was included in the electrolyte at anodic end of capillary. The stacking mechanism was similar to micelle to solvent stacking where the micelles were replaced by the microemulsion for the transport of analytes to the organic solvent rich boundary. This boundary is found between the microemulsion and anodic electrolyte. The effective electrophoretic mobility of the cations reversed from the direction of the anode in the microemulsion to the cathode in the boundary. Microemulsion to solvent stacking was successfully achieved with 40% ACN in the anodic electrolyte and hydrodynamic sample injection of 21 s at 1000 mbar (equivalent to 30% of the effective length). The sensitivity enhancement factors in terms of peak height and corrected peak area were 15 to 35 and 21 to 47, respectively. The linearity R(2) in terms of corrected peak area were >0.999. Interday precisions (%RSD, n = 6) were 3.3-4.0% for corrected peak area and 2.0-3.0% for migration time. Application to spiked real sample is also presented. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

49 CFR 178.606 - Stacking test.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 49 Transportation 3 2013-10-01 2013-10-01 false Stacking test. 178.606 Section 178.606... Packagings and Packages § 178.606 Stacking test. (a) General. All packaging design types other than bags must be subjected to a stacking test. (b) Number of test samples. Three test samples are required for each...

Analysis of anabolic androgenic steroids in urine by full-capillary sample injection combined with a sweeping CE stacking method.

PubMed

Wang, Chun-Chi; Cheng, Shu-Fang; Cheng, Hui-Ling; Chen, Yen-Ling

2013-02-01

This study describes an on-line stacking CE approach by sweeping with whole capillary sample filling for analyzing five anabolic androgenic steroids in urine samples. The five anabolic steroids for detection were androstenedione, testosterone, epitestosterone, boldenone, and clostebol. Anabolic androgenic steroids are abused in sport doping because they can promote muscle growth. Therefore, a sensitive detection method is imperatively required for monitoring the urine samples of athletes. In this research, an interesting and reliable stacking capillary electrophoresis method was established for analysis of anabolic steroids in urine. After liquid-liquid extraction by n-hexane, the supernatant was dried and reconstituted with 30 mM phosphate buffer (pH 5.00) and loaded into the capillary by hydrodynamic injection (10 psi, 99.9 s). The stacking and separation were simultaneously accomplished at -20 kV in phosphate buffer (30 mM, pH 5.0) containing 100 mM sodium dodecyl sulfate and 40 % methanol. During the method validation, calibration curves were linear (r≥0.990) over a range of 50-1,000 ng/mL for the five analytes. In the evaluation of precision and accuracy for this method, the absolute values of the RSD and the RE in the intra-day (n=3) and inter-day (n=5) analyses were all less than 6.6 %. The limit of detection for the five analytes was 30 ng/mL (S/N=5, sampling 99.9 s at 10 psi). Compared with simple MECK, this stacking method possessed a 108- to 175-fold increase in sensitivity. This simple and sensitive stacking method could be used as a powerful tool for monitoring the illegal use of doping.

Sample stacking of fast-moving anions in capillary zone electrophoresis with pH-suppressed electroosmotic flow.

PubMed

Quirino, J P; Terabe, S

1999-07-30

On-line sample concentration of fast moving inorganic anions by large volume sample stacking (LVSS) and field enhanced sample injection (FESI) with a water plug under acidic conditions is presented. Detection sensitivity enhancements were around 100 and 1000-fold for LVSS and FESI, respectively. However, reproducibility and linearity of response in the LVSS approach is superior compared to the FESI approach.

Mathematical modeling of sample stacking methods in microfluidic systems

NASA Astrophysics Data System (ADS)

Horek, Jon

Gradient focusing methods are a general class of experimental techniques used to simultaneously separate and increase the cross-sectionally averaged concentration of charged particle mixtures. In comparison, Field Amplified Sample Stacking (FASS) techniques first concentrate the collection of molecules before separating them. Together, we denote gradient focusing and FASS methods "sample stacking" and study the dynamics of a specific method, Temperature Gradient Focusing (TGF), in which an axial temperature gradient is applied along a channel filled with weak buffer. Gradients in electroosmotic fluid flow and electrophoretic species velocity create the simultaneous separating and concentrating mechanism mentioned above. In this thesis, we begin with the observation that very little has been done to model the dynamics of gradient focusing, and proceed to solve the fundamental equations of fluid mechanics and scalar transport, assuming the existence of slow axial variations and the Taylor-Aris dispersion coefficient. In doing so, asymptotic methods reduce the equations from 3D to 1D, and we arrive at a simple 1D model which can be used to predict the transient evolution of the cross-sectionally averaged analyte concentration. In the second half of this thesis, we run several numerical focusing experiments with a 3D finite volume code. Comparison of the 1D theory and 3D simulations illustrates not only that the asymptotic theory converges as a certain parameter tends to zero, but also that fairly large axial slip velocity gradients lead to quite small errors in predicted steady variance. Additionally, we observe that the axial asymmetry of the electrophoretic velocity model leads to asymmetric peak shapes, a violation of the symmetric Gaussians predicted by the 1D theory. We conclude with some observations on the effect of Peclet number and gradient strength on the performance of focusing experiments, and describe a method for experimental optimization. Such knowledge

Short protection device for stack of electrolytic cells

DOEpatents

Katz, Murray; Schroll, Craig R.

1985-10-22

Electrical short protection is provided in an electrolytic cell stack by the combination of a thin, nonporous ceramic shield and a noble metal foil disposed on opposite sides of the sealing medium in a gas manifold gasket. The thin ceramic shield, such as alumina, is placed between the porous gasket and the cell stack face at the margins of the negative end plate to the most negative cells to impede ion current flow. The noble metal foil, for instance gold, is electrically coupled to the negative potential of the stack to collect positive ions at a harmless location away from the stack face. Consequently, corrosion products from the stack structure deposit on the foil rather than on the stack face to eliminate electrical shorting of cells at the negative end of the stack.

Stack Characterization in CryoSat Level1b SAR/SARin Baseline C

NASA Astrophysics Data System (ADS)

Scagliola, Michele; Fornari, Marco; Di Giacinto, Andrea; Bouffard, Jerome; Féménias, Pierre; Parrinello, Tommaso

2015-04-01

CryoSat was launched on the 8th April 2010 and is the first European ice mission dedicated to the monitoring of precise changes in the thickness of polar ice sheets and floating sea ice. CryoSat is the first altimetry mission operating in SAR mode and it carries an innovative radar altimeter called the Synthetic Aperture Interferometric Altimeter (SIRAL), that transmits pulses at a high pulse repetition frequency thus making the received echoes phase coherent and suitable for azimuth processing. The current CryoSat IPF (Instrument Processing Facility), Baseline B, was released in operation in February 2012. After more than 2 years of development, the release in operations of the Baseline C is expected in the first half of 2015. It is worth recalling here that the CryoSat SAR/SARin IPF1 generates 20Hz waveforms in correspondence of an approximately equally spaced set of ground locations on the Earth surface, i.e. surface samples, and that a surface sample gathers a collection of single-look echoes coming from the processed bursts during the time of visibility. Thus, for a given surface sample, the stack can be defined as the collection of all the single-look echoes pointing to the current surface sample, after applying all the necessary range corrections. The L1B product contains the power average of all the single-look echoes in the stack: the multi-looked L1B waveform. This reduces the data volume, while removing some information contained in the single looks, useful for characterizing the surface and modelling the L1B waveform. To recover such information, a set of parameters has been added to the L1B product: the stack characterization or beam behaviour parameters. The stack characterization, already included in previous Baselines, has been reviewed and expanded in Baseline C. This poster describes all the stack characterization parameters, detailing what they represent and how they have been computed. In details, such parameters can be summarized in: - Stack

Partition/Ion-Exclusion Chromatographic Ion Stacking for the Analysis of Trace Anions in Water and Salt Samples by Ion Chromatography.

PubMed

Akter, Fouzia; Saito, Shingo; Tasaki-Handa, Yuiko; Shibukawa, Masami

2018-01-01

A new analytical methodology for a simple and efficient on-line preconcentration of trace inorganic anions in water and salt samples prior to ion chromatographic determination is proposed. The preconcentration method is based on partition/ion-exclusion chromatographic ion stacking (PIEC ion stacking) with a hydrophilic polymer gel column containing a small amount of fixed anionic charges. The developed on-line PIEC ion stacking-ion chromatography method was validated by recovery experiments for the determination of nitrate in tap water in terms of both accuracy and precision, and the results showed the reliability of the method. The method proposed was also successfully applied to the determination of trace impurity nitrite and nitrate in reagent-grade salts of sodium sulfate. A low background level can be achieved since pure water is used as the eluant for the PIEC ion stacking. It is possible to reach sensitive detection at sub-μg L -1 levels by on-line PIEC ion stacking-ion chromatography.

Preliminary design of a prototype particulate stack sampler. [For stack gas temperature under 300/sup 0/C

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

Elder, J.C.; Littlefield, L.G.; Tillery, M.I.

1978-06-01

A preliminary design of a prototype particulate stack sampler (PPSS) has been prepared, and development of several components is under way. The objective of this Environmental Protection Agency (EPA)-sponsored program is to develop and demonstrate a prototype sampler with capabilities similar to EPA Method 5 apparatus but without some of the more troublesome aspects. Features of the new design include higher sampling flow; display (on demand) of all variables and periodic calculation of percent isokinetic, sample volume, and stack velocity; automatic control of probe and filter heaters; stainless steel surfaces in contact with the sample stream; single-point particle size separationmore » in the probe nozzle; null-probe capability in the nozzle; and lower weight in the components of the sampling train. Design considerations will limit use of the PPSS to stack gas temperatures under approximately 300/sup 0/C, which will exclude sampling some high-temperature stacks such as incinerators. Although need for filter weighing has not been eliminated in the new design, introduction of a variable-slit virtual impactor nozzle may eliminate the need for mass analysis of particles washed from the probe. Component development has shown some promise for continuous humidity measurement by an in-line wet-bulb, dry-bulb psychrometer.« less

Method for monitoring stack gases for uranium activity

DOEpatents

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

1985-07-03

A method for monitoring the stack gases of a purge cascade of gaseous diffusion plant for uranium activity. A sample stream is taken from the stack gases and contacted with a volume of moisture-laden air for converting trace levels of uranium hexafluoride, if any, in the stack gases into particulate uranyl fluoride. A continuous strip of filter paper from a supply roll is passed through this sampling stream to intercept and gather any uranyl fluoride in the sampling stream. This filter paper is then passed by an alpha scintillation counting device where any radioactivity on the filter paper is sensed so as to provide a continuous monitoring of the gas stream for activity indicative of the uranium content in the stack gases. 1 fig.

Method for monitoring stack gases for uranium activity

DOEpatents

Beverly, Claude R.; Ernstberger, Harold G.

1988-01-01

A method for monitoring the stack gases of a purge cascade of a gaseous diffusion plant for uranium activity. A sample stream is taken from the stack gases and contacted with a volume of moisture-laden air for converting trace levels of uranium hexafluoride, if any, in the stack gases into particulate uranyl fluoride. A continuous strip of filter paper from a supply roll is passed through this sampling stream to intercept and gather any uranyl fluoride in the sampling stream. This filter paper is then passed by an alpha scintillation counting device where any radioactivity on the filter paper is sensed so as to provide a continuous monitoring of the gas stream for activity indicative of the uranium content in the stack gases.

Determination of finasteride and its metabolite in urine by dispersive liquid-liquid microextraction combined with field-enhanced sample stacking and sweeping.

PubMed

Chen, Chun-Hsien; Chao, Yu-Ying; Lin, Yi-Hui; Chen, Yen-Ling

2018-04-27

The on-line preconcentration technique of field-enhanced sample stacking and sweeping (FESS-sweeping) are combined with dispersive liquid-liquid microextraction (DLLME) to monitor the concentrations of finasteride, which is used in the treatment of androgenetic alopecia, and its metabolite, finasteride carboxylic acid (M3), in urine samples. DLLME is used to concentrate and eliminate the interferences of urine samples and uses chloroform as an extracting solvent and acetonitrile as a disperser solvent. A high conductivity buffer (HCB) was introduced into capillary and then sample plug (90.7% capillary length) was injected into capillary. After applying voltage, the sodium dodecyl sulfate (SDS) swept the analytes from the low conductivity sample solution into HCB. The analytes were concentrated on the field-enhanced sample stacking boundary. The limit of detection for the analytes is 20 ng mL -1 . The sensitivity enrichment of finasteride and M3 are 362-fold and 480-fold, respectively, compared with the conventional MEKC method. The on-line preconcentration technique of field-enhanced sample stacking and sweeping possess good selectivity because the endogenous steroid did not interfere the detection of finasteride and M3. The analytical technique is applied to investigate the concentrations in urine samples from patients who have been administered finasteride for the treatment of androgenetic alopecia; the amount of M3 detected in 12 h was 72.69 ± 4.18 μg. Copyright © 2018 Elsevier B.V. All rights reserved.

Additional Samples: Where They Should Be Located

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

Pilger, G. G., E-mail: jfelipe@ufrgs.br; Costa, J. F. C. L.; Koppe, J. C.

2001-09-15

Information for mine planning requires to be close spaced, if compared to the grid used for exploration and resource assessment. The additional samples collected during quasimining usually are located in the same pattern of the original diamond drillholes net but closer spaced. This procedure is not the best in mathematical sense for selecting a location. The impact of an additional information to reduce the uncertainty about the parameter been modeled is not the same everywhere within the deposit. Some locations are more sensitive in reducing the local and global uncertainty than others. This study introduces a methodology to select additionalmore » sample locations based on stochastic simulation. The procedure takes into account data variability and their spatial location. Multiple equally probable models representing a geological attribute are generated via geostatistical simulation. These models share basically the same histogram and the same variogram obtained from the original data set. At each block belonging to the model a value is obtained from the n simulations and their combination allows one to access local variability. Variability is measured using an uncertainty index proposed. This index was used to map zones of high variability. A value extracted from a given simulation is added to the original data set from a zone identified as erratic in the previous maps. The process of adding samples and simulation is repeated and the benefit of the additional sample is evaluated. The benefit in terms of uncertainty reduction is measure locally and globally. The procedure showed to be robust and theoretically sound, mapping zones where the additional information is most beneficial. A case study in a coal mine using coal seam thickness illustrates the method.« less

40 CFR 761.304 - Determining sample location.

Code of Federal Regulations, 2010 CFR

2010-07-01

.... (a) For 1 square meter non-porous surface areas having the same size and shape, it is permissible to sample the same 10 cm by 10 cm location or position in each identical 1 square meter area. This location or position is determined in accordance with § 761.306 or § 761.308. (b) If some 1 square meter...

40 CFR 761.304 - Determining sample location.

Code of Federal Regulations, 2013 CFR

2013-07-01

.... (a) For 1 square meter non-porous surface areas having the same size and shape, it is permissible to sample the same 10 cm by 10 cm location or position in each identical 1 square meter area. This location or position is determined in accordance with § 761.306 or § 761.308. (b) If some 1 square meter...

40 CFR 761.304 - Determining sample location.

Code of Federal Regulations, 2011 CFR

2011-07-01

.... (a) For 1 square meter non-porous surface areas having the same size and shape, it is permissible to sample the same 10 cm by 10 cm location or position in each identical 1 square meter area. This location or position is determined in accordance with § 761.306 or § 761.308. (b) If some 1 square meter...

40 CFR 761.304 - Determining sample location.

Code of Federal Regulations, 2014 CFR

2014-07-01

.... (a) For 1 square meter non-porous surface areas having the same size and shape, it is permissible to sample the same 10 cm by 10 cm location or position in each identical 1 square meter area. This location or position is determined in accordance with § 761.306 or § 761.308. (b) If some 1 square meter...

40 CFR 761.304 - Determining sample location.

Code of Federal Regulations, 2012 CFR

2012-07-01

.... (a) For 1 square meter non-porous surface areas having the same size and shape, it is permissible to sample the same 10 cm by 10 cm location or position in each identical 1 square meter area. This location or position is determined in accordance with § 761.306 or § 761.308. (b) If some 1 square meter...

Biomass bale stack and field outlet locations assessment for efficient infield logistics

USDA-ARS?s Scientific Manuscript database

Harvested hay or biomass are traditionally baled for better handling and they are transported to the outlet for final utilization. For better management of bale logistics, producers often aggregate bales into stacks so that bale-hauling equipment can haul multiple bales for improved efficiency. Obje...

Electrolyte matrix in a molten carbonate fuel cell stack

DOEpatents

Reiser, C.A.; Maricle, D.L.

1987-04-21

A fuel cell stack is disclosed with modified electrolyte matrices for limiting the electrolytic pumping and electrolyte migration along the stack external surfaces. Each of the matrices includes marginal portions at the stack face of substantially greater pore size than that of the central body of the matrix. Consequently, these marginal portions have insufficient electrolyte fill to support pumping or wicking of electrolyte from the center of the stack of the face surfaces in contact with the vertical seals. Various configurations of the marginal portions include a complete perimeter, opposite edge portions corresponding to the air plenums and tab size portions corresponding to the manifold seal locations. These margins will substantially limit the migration of electrolyte to and along the porous manifold seals during operation of the electrochemical cell stack. 6 figs.

Electrolyte matrix in a molten carbonate fuel cell stack

DOEpatents

Reiser, Carl A.; Maricle, Donald L.

1987-04-21

A fuel cell stack is disclosed with modified electrolyte matrices for limiting the electrolytic pumping and electrolyte migration along the stack external surfaces. Each of the matrices includes marginal portions at the stack face of substantially greater pore size than that of the central body of the matrix. Consequently, these marginal portions have insufficient electrolyte fill to support pumping or wicking of electrolyte from the center of the stack of the face surfaces in contact with the vertical seals. Various configurations of the marginal portions include a complete perimeter, opposite edge portions corresponding to the air plenums and tab size portions corresponding to the manifold seal locations. These margins will substantially limit the migration of electrolyte to and along the porous manifold seals during operation of the electrochemical cell stack.

Cooler and particulate separator for an off-gas stack

DOEpatents

Wright, George T.

1992-01-01

An off-gas stack for a melter comprising an air conduit leading to two sets of holes, one set injecting air into the off-gas stack near the melter plenum and the second set injecting air downstream of the first set. The first set injects air at a compound angle, having both downward and tangential components, to create a reverse vortex flow, counter to the direction of flow of gas through the stack and also along the periphery of the stack interior surface. Air from the first set of holes pervents recirculation zones from forming and the attendant accumulation of particulate deposits on the wall of the stack and will also return to the plenum any particulate swept up in the gas entering the stack. The second set of holes injects air in the same direction as the gas in the stack to compensate for the pressure drop and to prevent the concentration of condensate in the stack. A set of sprayers, receiving water from a second conduit, is located downstream of the second set of holes and sprays water into the gas to further cool it.

Cooler and particulate separator for an off-gas stack

DOEpatents

Wright, G.T.

1991-04-08

This report describes an off-gas stack for a melter, furnace or reaction vessel comprising an air conduit leading to two sets of holes, one set injecting air into the off-gas stack near the melter plenum and the second set injecting air downstream of the first set. The first set injects air at a compound angle, having both downward and tangential components, to create a reverse vortex flow, counter to the direction of flow of gas through the stack and also along the periphery of the stack interior surface. Air from the first set of holes prevents recirculation zones from forming and the attendant accumulation of particulate deposits on the wall of the stack and will also return to the plenum any particulate swept up in the gas entering the stack. The second set of holes injects air in the same direction as the gas in the stack to compensate for the pressure drop and to prevent the concentration of condensate in the stack. A set of sprayers, receiving water from a second conduit, is located downstream of the second set of holes and sprays water into the gas to further cool it.

Analysis of plant hormones by microemulsion electrokinetic capillary chromatography coupled with on-line large volume sample stacking.

PubMed

Chen, Zongbao; Lin, Zian; Zhang, Lin; Cai, Yan; Zhang, Lan

2012-04-07

A novel method of microemulsion electrokinetic capillary chromatography (MEEKC) coupled with on-line large volume sample stacking was developed for the analysis of six plant hormones including indole-3-acetic acid, indole-3-butyric acid, indole-3-propionic acid, 1-naphthaleneacetic acid, abscisic acid and salicylic acid. Baseline separation of six plant hormones was achieved within 10 min by using the microemulsion background electrolyte containing a 97.2% (w/w) 10 mM borate buffer at pH 9.2, 1.0% (w/w) ethyl acetate as oil droplets, 0.6% (w/w) sodium dodecyl sulphate as surfactant and 1.2% (w/w) 1-butanol as cosurfactant. In addition, an on-line concentration method based on a large volume sample stacking technique and multiple wavelength detection was adopted for improving the detection sensitivity in order to determine trace level hormones in a real sample. The optimal method provided about 50-100 fold increase in detection sensitivity compared with a single MEEKC method, and the detection limits (S/N = 3) were between 0.005 and 0.02 μg mL(-1). The proposed method was simple, rapid and sensitive and could be applied to the determination of six plant hormones in spiked water samples, tobacco leaves and 1-naphthylacetic acid in leaf fertilizer. The recoveries ranged from 76.0% to 119.1%, and good reproducibilities were obtained with relative standard deviations (RSDs) less than 6.6%.

Electrochemical Detection in Stacked Paper Networks.

PubMed

Liu, Xiyuan; Lillehoj, Peter B

2015-08-01

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.

Probing Temperature Inside Planar SOFC Short Stack, Modules, and Stack Series

NASA Astrophysics Data System (ADS)

Yu, Rong; Guan, Wanbing; Zhou, Xiao-Dong

2017-02-01

Probing temperature inside a solid oxide fuel cell (SOFC) stack lies at the heart of the development of high-performance and stable SOFC systems. In this article, we report our recent work on the direct measurements of the temperature in three types of SOFC systems: a 5-cell short stack, a 30-cell stack module, and a stack series consisting of two 30-cell stack modules. The dependence of temperature on the gas flow rate and current density was studied under a current sweep or steady-state operation. During the current sweep, the temperature inside the 5-cell stack decreased with increasing current, while it increased significantly at the bottom and top of the 30-cell stack. During a steady-state operation, the temperature of the 5-cell stack was stable while it was increased in the 30-cell stack. In the stack series, the maximum temperature gradient reached 190°C when the gas was not preheated. If the gas was preheated and the temperature gradient was reduced to 23°C in the stack series with the presence of a preheating gas and segmented temperature control, this resulted in a low degradation rate.

Building Extraction Based on an Optimized Stacked Sparse Autoencoder of Structure and Training Samples Using LIDAR DSM and Optical Images.

PubMed

Yan, Yiming; Tan, Zhichao; Su, Nan; Zhao, Chunhui

2017-08-24

In this paper, a building extraction method is proposed based on a stacked sparse autoencoder with an optimized structure and training samples. Building extraction plays an important role in urban construction and planning. However, some negative effects will reduce the accuracy of extraction, such as exceeding resolution, bad correction and terrain influence. Data collected by multiple sensors, as light detection and ranging (LIDAR), optical sensor etc., are used to improve the extraction. Using digital surface model (DSM) obtained from LIDAR data and optical images, traditional method can improve the extraction effect to a certain extent, but there are some defects in feature extraction. Since stacked sparse autoencoder (SSAE) neural network can learn the essential characteristics of the data in depth, SSAE was employed to extract buildings from the combined DSM data and optical image. A better setting strategy of SSAE network structure is given, and an idea of setting the number and proportion of training samples for better training of SSAE was presented. The optical data and DSM were combined as input of the optimized SSAE, and after training by an optimized samples, the appropriate network structure can extract buildings with great accuracy and has good robustness.

Macromolecular differentiation of Golgi stacks in root tips of Arabidopsis and Nicotiana seedlings as visualized in high pressure frozen and freeze-substituted samples

NASA Technical Reports Server (NTRS)

Staehelin, L. A.; Giddings, T. H. Jr; Kiss, J. Z.; Sack, F. D.

1990-01-01

The plant root tip represents a fascinating model system for studying changes in Golgi stack architecture associated with the developmental progression of meristematic cells to gravity sensing columella cells, and finally to "young" and "old", polysaccharide-slime secreting peripheral cells. To this end we have used high pressure freezing in conjunction with freeze-substitution techniques to follow developmental changes in the macromolecular organization of Golgi stacks in root tips of Arabidopsis and Nicotiana. Due to the much improved structural preservation of all cells under investigation, our electron micrographs reveal both several novel structural features common to all Golgi stacks, as well as characteristic differences in morphology between Golgi stacks of different cell types. Common to all Golgi stacks are clear and discrete differences in staining patterns and width of cis, medial and trans cisternae. Cis cisternae have the widest lumina (approximately 30 nm) and are the least stained. Medial cisternae are narrower (approximately 20 nm) and filled with more darkly staining products. Most trans cisternae possess a completely collapsed lumen in their central domain, giving rise to a 4-6 nm wide dark line in cross-sectional views. Numerous vesicles associated with the cisternal margins carry a non-clathrin type of coat. A trans Golgi network with clathrin coated vesicles is associated with all Golgi stacks except those of old peripheral cells. It is easily distinguished from trans cisternae by its blebbing morphology and staining pattern. The zone of ribosome exclusion includes both the Golgi stack and the trans Golgi network. Intercisternal elements are located exclusively between trans cisternae of columella and peripheral cells, but not meristematic cells. In older peripheral cells only trans cisternae exhibit slime-related staining. Golgi stacks possessing intercisternal elements also contain parallel rows of freeze-fracture particles in their trans

A double-correlation tremor-location method

NASA Astrophysics Data System (ADS)

Li, Ka Lok; Sgattoni, Giulia; Sadeghisorkhani, Hamzeh; Roberts, Roland; Gudmundsson, Olafur

2017-02-01

A double-correlation method is introduced to locate tremor sources based on stacks of complex, doubly-correlated tremor records of multiple triplets of seismographs back projected to hypothetical source locations in a geographic grid. Peaks in the resulting stack of moduli are inferred source locations. The stack of the moduli is a robust measure of energy radiated from a point source or point sources even when the velocity information is imprecise. Application to real data shows how double correlation focuses the source mapping compared to the common single correlation approach. Synthetic tests demonstrate the robustness of the method and its resolution limitations which are controlled by the station geometry, the finite frequency of the signal, the quality of the used velocity information and noise level. Both random noise and signal or noise correlated at time shifts that are inconsistent with the assumed velocity structure can be effectively suppressed. Assuming a surface wave velocity, we can constrain the source location even if the surface wave component does not dominate. The method can also in principle be used with body waves in 3-D, although this requires more data and seismographs placed near the source for depth resolution.

49 CFR 178.606 - Stacking test.

Code of Federal Regulations, 2014 CFR

2014-10-01

... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) SPECIFICATIONS FOR PACKAGINGS Testing of Non-bulk.... (c) Test method—(1) Design qualification testing. The test sample must be subjected to a force... might be stacked on it during transport; where the contents of the test sample are non-hazardous liquids...

49 CFR 178.606 - Stacking test.

Code of Federal Regulations, 2012 CFR

2012-10-01

... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) SPECIFICATIONS FOR PACKAGINGS Testing of Non-bulk.... (c) Test method—(1) Design qualification testing. The test sample must be subjected to a force... might be stacked on it during transport; where the contents of the test sample are non-hazardous liquids...

49 CFR 178.606 - Stacking test.

Code of Federal Regulations, 2011 CFR

2011-10-01

... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) SPECIFICATIONS FOR PACKAGINGS Testing of Non-bulk.... (c) Test method—(1) Design qualification testing. The test sample must be subjected to a force... might be stacked on it during transport; where the contents of the test sample are non-hazardous liquids...

Microchip electrophoresis of oligosaccharides using large-volume sample stacking with an electroosmotic flow pump in a single channel.

PubMed

Kawai, Takayuki; Sueyoshi, Kenji; Kitagawa, Fumihiko; Otsuka, Koji

2010-08-01

The applicability of an online preconcentration technique, large-volume sample stacking with an electroosmotic flow pump (LVSEP), to microchip zone electrophoresis (MCZE) for the analysis of oligosaccharides was investigated. Since the sample stacking and separation proceeded continuously without polarity switching in LVSEP, a single "straight" channel microchip could be employed. In the MCZE analysis of oligosaccharides, sample adsorption onto the channel surface should be suppressed, so the straight microchannel was modified with poly(vinyl alcohol) (PVA). So far, the mechanism of LVSEP in the polymer-coated capillary or microchannel has not been reported, and thus, the LVSEP process in the PVA-coated channel was investigated by fluorescence imaging. Although it is well-known that the PVA coating can suppress the electroosmotic flow (EOF), an enhanced EOF with a mobility of 4.4 x 10(-4) cm(2)/(V x s) was observed in a low ionic strength sample solution. It was revealed that such temporarily enhanced EOF in the sample zone worked as the driving force to remove the sample matrix in LVSEP. To evaluate the analytical performance of LVSEP-MCZE, oligosaccharides were analyzed in the PVA-coated straight channel. As a result, both the glucose ladder and oligosaccharides obtained from bovine ribonuclease B were well enriched and separated with up to 2200-2900-fold sensitivity enhancement compared to those in a conventional MCZE analysis. The run-to-run repeatabilities of the migration time and peak height were good with relative standard deviations of 1.1% and 7.2%, respectively, which were better than those of normal MCZE. By applying the LVSEP technique to MCZE, a complicated voltage program for fluidic control could be simplified from four channels for two steps to two channels for one step.

Determination of geostatistically representative sampling locations in Porsuk Dam Reservoir (Turkey)

NASA Astrophysics Data System (ADS)

Aksoy, A.; Yenilmez, F.; Duzgun, S.

2013-12-01

Several factors such as wind action, bathymetry and shape of a lake/reservoir, inflows, outflows, point and diffuse pollution sources result in spatial and temporal variations in water quality of lakes and reservoirs. The guides by the United Nations Environment Programme and the World Health Organization to design and implement water quality monitoring programs suggest that even a single monitoring station near the center or at the deepest part of a lake will be sufficient to observe long-term trends if there is good horizontal mixing. In stratified water bodies, several samples can be required. According to the guide of sampling and analysis under the Turkish Water Pollution Control Regulation, a minimum of five sampling locations should be employed to characterize the water quality in a reservoir or a lake. The European Union Water Framework Directive (2000/60/EC) states to select a sufficient number of monitoring sites to assess the magnitude and impact of point and diffuse sources and hydromorphological pressures in designing a monitoring program. Although existing regulations and guidelines include frameworks for the determination of sampling locations in surface waters, most of them do not specify a procedure in establishment of monitoring aims with representative sampling locations in lakes and reservoirs. In this study, geostatistical tools are used to determine the representative sampling locations in the Porsuk Dam Reservoir (PDR). Kernel density estimation and kriging were used in combination to select the representative sampling locations. Dissolved oxygen and specific conductivity were measured at 81 points. Sixteen of them were used for validation. In selection of the representative sampling locations, care was given to keep similar spatial structure in distributions of measured parameters. A procedure was proposed for that purpose. Results indicated that spatial structure was lost under 30 sampling points. This was as a result of varying water

Generic particulate-monitoring system for retrofit to Hanford exhaust stacks

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

Camman, J.W.; Carbaugh, E.H.

1982-11-01

Evaluations of 72 sampling and monitoring systems were performed at Hanford as the initial phase of a program to upgrade such systems. Each evaluation included determination of theoretical sampling efficiencies for particle sizes ranging from 0.5 to 10 micrometers aerodynamic equivalent diameter, addressing anisokinetic bias, sample transport line losses, and collector device efficiency. Upgrades needed to meet current Department of Energy guidance for effluent sampling and monitoring were identified, and a cost for each upgrade was estimated. A relative priority for each system's upgrade was then established based on evaluation results, current operational status, and future plans for the facilitymore » being exhausted. Common system upgrade requirements lead to the development of a generic design for common components of an exhaust stack sampling and monitoring system for airborne radioactive particulates. The generic design consists of commercially available off-the-shelf components to the extent practical and will simplify future stack sampling and monitoring system design, fabrication, and installation efforts. Evaluation results and their significance to system upgrades are empasized. A brief discussion of the analytical models used and experience to date with the upgrade program is included. Development of the generic stack sampling and monitoring system design is outlined. Generic system design features and limitations are presented. Requirements for generic system retrofitting to existing exhaust stacks are defined and benefits derived from generic system application are discussed.« less

Combination of micelle collapse and field-amplified sample stacking in capillary electrophoresis for determination of trimethoprim and sulfamethoxazole in animal-originated foodstuffs.

PubMed

Liu, Lihong; Wan, Qian; Xu, Xiaoying; Duan, Shunshan; Yang, Chunli

2017-03-15

An on-line preconcentration method combining micelle to solvent stacking (MSS) with field-amplified sample stacking (FASS) was employed for the analysis of trimethoprim (TMP) and sulfamethoxazole (SMZ) by capillary zone electrophoresis (CZE). The optimized experimental conditions were as followings: (1) sample matrix, 10.0mM SDS-5% (v/v) methanol; (2) trapping solution (TS), 35mM H 3 PO 4 -60% acetonitrile (CH 3 CN); (3) running buffer, 30mM Na 2 HPO 4 (pH=7.3); (4) sample solution volume, 168nL; TS volume, 168nL; and (5) 9kV voltage, 214nm UV detection. Under the optimized conditions, the limits of detection (LODs) for SMZ and TMP were 7.7 and 8.5ng/mL, and they were 301 and 329 times better compared to a typical injection, respectively. The contents of TMP and SMZ in animal foodstuffs such as dairy products, eggs and honey were analyzed, too. Recoveries of 80-104% were acquired with relative standard deviations of 0.5-5.4%. Copyright © 2016 Elsevier Ltd. All rights reserved.

Attachment method for stacked integrated circuit (IC) chips

DOEpatents

Bernhardt, A.F.; Malba, V.

1999-08-03

An attachment method for stacked integrated circuit (IC) chips is disclosed. The method involves connecting stacked chips, such as DRAM memory chips, to each other and/or to a circuit board. Pads on the individual chips are rerouted to form pads on the side of the chip, after which the chips are stacked on top of each other whereby desired interconnections to other chips or a circuit board can be accomplished via the side-located pads. The pads on the side of a chip are connected to metal lines on a flexible plastic tape (flex) by anisotropically conductive adhesive (ACA). Metal lines on the flex are likewise connected to other pads on chips and/or to pads on a circuit board. In the case of a stack of DRAM chips, pads to corresponding address lines on the various chips may be connected to the same metal line on the flex to form an address bus. This method has the advantage of reducing the number of connections required to be made to the circuit board due to bussing; the flex can accommodate dimensional variation in the alignment of chips in the stack; bonding of the ACA is accomplished at low temperature and is otherwise simpler and less expensive than solder bonding; chips can be bonded to the ACA all at once if the sides of the chips are substantially coplanar, as in the case for stacks of identical chips, such as DRAM. 12 figs.

Attachment method for stacked integrated circuit (IC) chips

DOEpatents

Bernhardt, Anthony F.; Malba, Vincent

1999-01-01

An attachment method for stacked integrated circuit (IC) chips. The method involves connecting stacked chips, such as DRAM memory chips, to each other and/or to a circuit board. Pads on the individual chips are rerouted to form pads on the side of the chip, after which the chips are stacked on top of each other whereby desired interconnections to other chips or a circuit board can be accomplished via the side-located pads. The pads on the side of a chip are connected to metal lines on a flexible plastic tape (flex) by anisotropically conductive adhesive (ACA). Metal lines on the flex are likewise connected to other pads on chips and/or to pads on a circuit board. In the case of a stack of DRAM chips, pads to corresponding address lines on the various chips may be connected to the same metal line on the flex to form an address bus. This method has the advantage of reducing the number of connections required to be made to the circuit board due to bussing; the flex can accommodate dimensional variation in the alignment of chips in the stack; bonding of the ACA is accomplished at low temperature and is otherwise simpler and less expensive than solder bonding; chips can be bonded to the ACA all at once if the sides of the chips are substantially coplanar, as in the case for stacks of identical chips, such as DRAM.

Complex and noncentrosymmetric stacking of layered metal dichalcogenide materials created by screw dislocations

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

Shearer, Melinda J.; Samad, Leith; Zhang, Yi

The interesting and tunable properties of layered metal dichalcogenides heavily depend on their phase and layer stacking. Here, we show and explain how the layer stacking and physical properties of WSe 2 are influenced by screw dislocations. A one-to-one correlation of atomic force microscopy and high- and low-frequency Raman spectroscopy of many dislocated WSe 2 nanoplates reveals variations in the number and shapes of dislocation spirals and different layer stackings that are determined by the number, rotation, and location of the dislocations. Plates with triangular dislocation spirals form noncentrosymmetric stacking that gives rise to strong second-harmonic generation and enhanced photoluminescence,more » plates with hexagonal dislocation spirals form the bulk 2H layer stacking commonly observed, and plates containing mixed dislocation shapes have intermediate noncentrosymmetric stackings with mixed properties. Multiple dislocation cores and other complexities can lead to more complex stackings and properties. Finally, these previously unobserved properties and layer stackings in WSe 2 will be interesting for spintronics and valleytronics.« less

Complex and noncentrosymmetric stacking of layered metal dichalcogenide materials created by screw dislocations

DOE PAGES

Shearer, Melinda J.; Samad, Leith; Zhang, Yi; ...

2017-02-08

The interesting and tunable properties of layered metal dichalcogenides heavily depend on their phase and layer stacking. Here, we show and explain how the layer stacking and physical properties of WSe 2 are influenced by screw dislocations. A one-to-one correlation of atomic force microscopy and high- and low-frequency Raman spectroscopy of many dislocated WSe 2 nanoplates reveals variations in the number and shapes of dislocation spirals and different layer stackings that are determined by the number, rotation, and location of the dislocations. Plates with triangular dislocation spirals form noncentrosymmetric stacking that gives rise to strong second-harmonic generation and enhanced photoluminescence,more » plates with hexagonal dislocation spirals form the bulk 2H layer stacking commonly observed, and plates containing mixed dislocation shapes have intermediate noncentrosymmetric stackings with mixed properties. Multiple dislocation cores and other complexities can lead to more complex stackings and properties. Finally, these previously unobserved properties and layer stackings in WSe 2 will be interesting for spintronics and valleytronics.« less

GRIM-Filter: Fast seed location filtering in DNA read mapping using processing-in-memory technologies.

PubMed

Kim, Jeremie S; Senol Cali, Damla; Xin, Hongyi; Lee, Donghyuk; Ghose, Saugata; Alser, Mohammed; Hassan, Hasan; Ergin, Oguz; Alkan, Can; Mutlu, Onur

2018-05-09

Seed location filtering is critical in DNA read mapping, a process where billions of DNA fragments (reads) sampled from a donor are mapped onto a reference genome to identify genomic variants of the donor. State-of-the-art read mappers 1) quickly generate possible mapping locations for seeds (i.e., smaller segments) within each read, 2) extract reference sequences at each of the mapping locations, and 3) check similarity between each read and its associated reference sequences with a computationally-expensive algorithm (i.e., sequence alignment) to determine the origin of the read. A seed location filter comes into play before alignment, discarding seed locations that alignment would deem a poor match. The ideal seed location filter would discard all poor match locations prior to alignment such that there is no wasted computation on unnecessary alignments. We propose a novel seed location filtering algorithm, GRIM-Filter, optimized to exploit 3D-stacked memory systems that integrate computation within a logic layer stacked under memory layers, to perform processing-in-memory (PIM). GRIM-Filter quickly filters seed locations by 1) introducing a new representation of coarse-grained segments of the reference genome, and 2) using massively-parallel in-memory operations to identify read presence within each coarse-grained segment. Our evaluations show that for a sequence alignment error tolerance of 0.05, GRIM-Filter 1) reduces the false negative rate of filtering by 5.59x-6.41x, and 2) provides an end-to-end read mapper speedup of 1.81x-3.65x, compared to a state-of-the-art read mapper employing the best previous seed location filtering algorithm. GRIM-Filter exploits 3D-stacked memory, which enables the efficient use of processing-in-memory, to overcome the memory bandwidth bottleneck in seed location filtering. We show that GRIM-Filter significantly improves the performance of a state-of-the-art read mapper. GRIM-Filter is a universal seed location filter that can be

A Late Pleistocene sea level stack

NASA Astrophysics Data System (ADS)

Spratt, Rachel M.; Lisiecki, Lorraine E.

2016-04-01

Late Pleistocene sea level has been reconstructed from ocean sediment core data using a wide variety of proxies and models. However, the accuracy of individual reconstructions is limited by measurement error, local variations in salinity and temperature, and assumptions particular to each technique. Here we present a sea level stack (average) which increases the signal-to-noise ratio of individual reconstructions. Specifically, we perform principal component analysis (PCA) on seven records from 0 to 430 ka and five records from 0 to 798 ka. The first principal component, which we use as the stack, describes ˜ 80 % of the variance in the data and is similar using either five or seven records. After scaling the stack based on Holocene and Last Glacial Maximum (LGM) sea level estimates, the stack agrees to within 5 m with isostatically adjusted coral sea level estimates for Marine Isotope Stages 5e and 11 (125 and 400 ka, respectively). Bootstrapping and random sampling yield mean uncertainty estimates of 9-12 m (1σ) for the scaled stack. Sea level change accounts for about 45 % of the total orbital-band variance in benthic δ18O, compared to a 65 % contribution during the LGM-to-Holocene transition. Additionally, the second and third principal components of our analyses reflect differences between proxy records associated with spatial variations in the δ18O of seawater.

Pressurized Testing of Solid Oxide Electrolysis Stacks with Advanced Electrode-Supported Cells

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

J. E. O'Brien; X. Zhang; G. K. Housley

2012-06-01

A new facility has been developed at the Idaho National Laboratory for pressurized testing of solid oxide electrolysis stacks. Pressurized operation is envisioned for large-scale hydrogen production plants, yielding higher overall efficiencies when the hydrogen product is to be delivered at elevated pressure for tank storage or pipelines. Pressurized operation also supports higher mass flow rates of the process gases with smaller components. The test stand can accommodate cell dimensions up to 8.5 cm x 8.5 cm and stacks of up to 25 cells. The pressure boundary for these tests is a water-cooled spool-piece pressure vessel designed for operation upmore » to 5 MPa. The stack is internally manifolded and operates in cross-flow with an inverted-U flow pattern. Feed-throughs for gas inlets/outlets, power, and instrumentation are all located in the bottom flange. The entire spool piece, with the exception of the bottom flange, can be lifted to allow access to the internal furnace and test fixture. Lifting is accomplished with a motorized threaded drive mechanism attached to a rigid structural frame. Stack mechanical compression is accomplished using springs that are located inside of the pressure boundary, but outside of the hot zone. Initial stack heatup and performance characterization occurs at ambient pressure followed by lowering and sealing of the pressure vessel and subsequent pressurization. Pressure equalization between the anode and cathode sides of the cells and the stack surroundings is ensured by combining all of the process gases downstream of the stack. Steady pressure is maintained by means of a backpressure regulator and a digital pressure controller. A full description of the pressurized test apparatus is provided in this paper.« less

Stack sampling apparatus

DOEpatents

Lind, Randall F; Lloyd, Peter D; Love, Lonnie J; Noakes, Mark W; Pin, Francois G; Richardson, Bradley S; Rowe, John C

2014-09-16

An apparatus for obtaining samples from a structure includes a support member, at least one stabilizing member, and at least one moveable member. The stabilizing member has a first portion coupled to the support member and a second portion configured to engage with the structure to restrict relative movement between the support member and the structure. The stabilizing member is radially expandable from a first configuration where the second portion does not engage with a surface of the structure to a second configuration where the second portion engages with the surface of the structure.

Thermal stress analysis of a planar SOFC stack

NASA Astrophysics Data System (ADS)

Lin, Chih-Kuang; Chen, Tsung-Ting; Chyou, Yau-Pin; Chiang, Lieh-Kwang

The aim of this study is, by using finite element analysis (FEA), to characterize the thermal stress distribution in a planar solid oxide fuel cell (SOFC) stack during various stages. The temperature profiles generated by an integrated thermo-electrochemical model were applied to calculate the thermal stress distributions in a multiple-cell SOFC stack by using a three-dimensional (3D) FEA model. The constructed 3D FEA model consists of the complete components used in a practical SOFC stack, including positive electrode-electrolyte-negative electrode (PEN) assembly, interconnect, nickel mesh, and gas-tight glass-ceramic seals. Incorporation of the glass-ceramic sealant, which was never considered in previous studies, into the 3D FEA model would produce more realistic results in thermal stress analysis and enhance the reliability of predicting potential failure locations in an SOFC stack. The effects of stack support condition, viscous behavior of the glass-ceramic sealant, temperature gradient, and thermal expansion mismatch between components were characterized. Modeling results indicated that a change in the support condition at the bottom frame of the SOFC stack would not cause significant changes in thermal stress distribution. Thermal stress distribution did not differ significantly in each unit cell of the multiple-cell stack due to a comparable in-plane temperature profile. By considering the viscous characteristics of the glass-ceramic sealant at temperatures above the glass-transition temperature, relaxation of thermal stresses in the PEN was predicted. The thermal expansion behavior of the metallic interconnect/frame had a greater influence on the thermal stress distribution in the PEN than did that of the glass-ceramic sealant due to the domination of interconnect/frame in the volume of a planar SOFC assembly.

Application of particle size distributions to total particulate stack samples to estimate PM2.5 and PM10 emission factors for agricultural sources

USDA-ARS?s Scientific Manuscript database

Particle size distributions (PSD) have long been used to more accurately estimate the PM10 fraction of total particulate matter (PM) stack samples taken from agricultural sources. These PSD analyses were typically conducted using a Coulter Counter with 50 micrometer aperture tube. With recent increa...

Stacking with stochastic cooling

NASA Astrophysics Data System (ADS)

Caspers, Fritz; Möhl, Dieter

2004-10-01

Accumulation of large stacks of antiprotons or ions with the aid of stochastic cooling is more delicate than cooling a constant intensity beam. Basically the difficulty stems from the fact that the optimized gain and the cooling rate are inversely proportional to the number of particles 'seen' by the cooling system. Therefore, to maintain fast stacking, the newly injected batch has to be strongly 'protected' from the Schottky noise of the stack. Vice versa the stack has to be efficiently 'shielded' against the high gain cooling system for the injected beam. In the antiproton accumulators with stacking ratios up to 105 the problem is solved by radial separation of the injection and the stack orbits in a region of large dispersion. An array of several tapered cooling systems with a matched gain profile provides a continuous particle flux towards the high-density stack core. Shielding of the different systems from each other is obtained both through the spatial separation and via the revolution frequencies (filters). In the 'old AA', where the antiproton collection and stacking was done in one single ring, the injected beam was further shielded during cooling by means of a movable shutter. The complexity of these systems is very high. For more modest stacking ratios, one might use azimuthal rather than radial separation of stack and injected beam. Schematically half of the circumference would be used to accept and cool new beam and the remainder to house the stack. Fast gating is then required between the high gain cooling of the injected beam and the low gain stack cooling. RF-gymnastics are used to merge the pre-cooled batch with the stack, to re-create free space for the next injection, and to capture the new batch. This scheme is less demanding for the storage ring lattice, but at the expense of some reduction in stacking rate. The talk reviews the 'radial' separation schemes and also gives some considerations to the 'azimuthal' schemes.

Nondestructive cell evaluation techniques in SOFC stack manufacturing

NASA Astrophysics Data System (ADS)

Wunderlich, C.

2016-04-01

Independent from the specifics of the application, a cost efficient manufacturing of solid oxide fuel cells (SOFC), its electrolyte membranes and other stack components, leading to reliable long-life stacks is the key for the commercial viability of this fuel cell technology. Tensile and shear stresses are most critical for ceramic components and especially for thin electrolyte membranes as used in SOFC cells. Although stack developers try to reduce tensile stresses acting on the electrolyte by either matching CTE of interconnects and electrolytes or by putting SOFC cells under some pressure - at least during transient operation of SOFC stacks ceramic cells will experience some tensile stresses. Electrolytes are required to have a high Weibull characteristic fracture strength. Practical experiences in stack manufacturing have shown that statistical fracture strength data generated by tests of electrolyte samples give limited information on electrolyte or cell quality. In addition, the cutting process of SOFC electrolytes has a major influence on crack initiation. Typically, any single crack in one the 30 to 80 cells in series connection will lead to a premature stack failure drastically reducing stack service life. Thus, for statistical reasons only 100% defect free SOFC cells must be assembled in stacks. This underlines the need for an automated inspection. So far, only manual processes of visual or mechanical electrolyte inspection are established. Fraunhofer IKTS has qualified the method of optical coherence tomography for an automated high throughput inspection. Alternatives like laser speckle photometry and acoustical methods are still under investigation.

Improved Direct Methanol Fuel Cell Stack

DOEpatents

Wilson, Mahlon S.; Ramsey, John C.

2005-03-08

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.

Weighted stacking of seismic AVO data using hybrid AB semblance and local similarity

NASA Astrophysics Data System (ADS)

Deng, Pan; Chen, Yangkang; Zhang, Yu; Zhou, Hua-Wei

2016-04-01

The common-midpoint (CMP) stacking technique plays an important role in enhancing the signal-to-noise ratio (SNR) in seismic data processing and imaging. Weighted stacking is often used to improve the performance of conventional equal-weight stacking in further attenuating random noise and handling the amplitude variations in real seismic data. In this study, we propose to use a hybrid framework of combining AB semblance and a local-similarity-weighted stacking scheme. The objective is to achieve an optimal stacking of the CMP gathers with class II amplitude-variation-with-offset (AVO) polarity-reversal anomaly. The selection of high-quality near-offset reference trace is another innovation of this work because of its better preservation of useful energy. Applications to synthetic and field seismic data demonstrate a great improvement using our method to capture the true locations of weak reflections, distinguish thin-bed tuning artifacts, and effectively attenuate random noise.

Steinhaus’ Geometric Location Problem for Random Samples in the Plane.

DTIC Science & Technology

1982-05-11

NAL 411R A1, ’I 7 - I STEINHAUS ’ GEOMETRIC LOCATION PROBLEM FOR RANDOM SAMPLES IN THE PLANE By Dorit Hochbaum and J. Michael Steele TECHNICAL REPORT...DEPARTMENT OF STATISTICS -Dltrib’ytion/ STANFORD UNIVERSITY A-I.abilty Codes STANFORD, CALIFORNIA Dist Spciat ecial Steinhaus ’ Geometric Location Problem for...Random Samples in the Plane By Dorit Hochbaum and J. Michael Steele I. Introduction. The work of H. Steinhaus U wf94 as apparently the first explicit

A High Volume Stack Sampler

NASA Technical Reports Server (NTRS)

Boubel, Richard W.

1971-01-01

The stack sampler described in this paper has been developed to overcome the difficulties of particulate sampling with presently available equipment. Its use on emissions from hog fuel fired boilers, back-fired incinerators, wigwam burners, asphalt plants, and seed cleaning cyclones is reported. The results indicate that the sampler is rapid and reliable in its use. It is relatively simple and inexpensive to operate. For most sources it should be considered over the more complicated and expensive sampling trains being used and specified.

Electrochemical cell stack assembly

DOEpatents

Jacobson, Craig P.; Visco, Steven J.; De Jonghe, Lutgard C.

2010-06-22

Multiple stacks of tubular electrochemical cells having a dense electrolyte disposed between an anode and a cathode preferably deposited as thin films arranged in parallel on stamped conductive interconnect sheets or ferrules. The stack allows one or more electrochemical cell to malfunction without disabling the entire stack. Stack efficiency is enhanced through simplified gas manifolding, gas recycling, reduced operating temperature and improved heat distribution.

Stacking fault density and bond orientational order of fcc ruthenium nanoparticles

NASA Astrophysics Data System (ADS)

Seo, Okkyun; Sakata, Osami; Kim, Jae Myung; Hiroi, Satoshi; Song, Chulho; Kumara, Loku Singgappulige Rosantha; Ohara, Koji; Dekura, Shun; Kusada, Kohei; Kobayashi, Hirokazu; Kitagawa, Hiroshi

2017-12-01

We investigated crystal structure deviations of catalytic nanoparticles (NPs) using synchrotron powder X-ray diffraction. The samples were fcc ruthenium (Ru) NPs with diameters of 2.4, 3.5, 3.9, and 5.4 nm. We analyzed average crystal structures by applying the line profile method to a stacking fault model and local crystal structures using bond orientational order (BOO) parameters. The reflection peaks shifted depending on rules that apply to each stacking fault. We evaluated the quantitative stacking faults densities for fcc Ru NPs, and the stacking fault per number of layers was 2-4, which is quite large. Our analysis shows that the fcc Ru 2.4 nm-diameter NPs have a considerably high stacking fault density. The B factor tends to increase with the increasing stacking fault density. A structural parameter that we define from the BOO parameters exhibits a significant difference from the ideal value of the fcc structure. This indicates that the fcc Ru NPs are highly disordered.

23. Brick coke quencher, brick stack, metal stack to right, ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

23. Brick coke quencher, brick stack, metal stack to right, coke gas pipe to left; in background, BOF building, limestone piles, Levy's Slag Dump. Looking north/northwest - Rouge Steel Company, 3001 Miller Road, Dearborn, MI

Characteristics of nonlinear imaging of broadband laser stacked by chirped pulses

NASA Astrophysics Data System (ADS)

Wang, Youwen; You, Kaiming; Chen, Liezun; Lu, Shizhuan; Dai, Zhiping; Ling, Xiaohui

2014-11-01

Nanosecond-level pulses of specific shape is usually generated by stacking chirped pulses for high-power inertial confinement fusion driver, in which nonlinear imaging of scatterers may damage precious optical elements. We present a numerical study of the characteristics of nonlinear imaging of scatterers in broadband laser stacked by chirped pulses to disclose the dependence of location and intensity of images on the parameters of the stacked pulse. It is shown that, for sub-nanosecond long sub-pulses with chirp or transform-limited sub-pulses, the time-mean intensity and location of images through normally dispersive and anomalously dispersive self-focusing medium slab are almost identical; While for picosecond-level short sub-pulses with chirp, the time-mean intensity of images for weak normal dispersion is slightly higher than that for weak anomalous dispersion through a thin nonlinear slab; the result is opposite to that for strong dispersion in a thick nonlinear slab; Furthermore, for given time delay between neighboring sub-pulses, the time-mean intensity of images varies periodically with chirp of the sub-pulse increasing; for a given pulse width of sub-pulse, the time-mean intensity of images decreases with the time delay between neighboring sub-pulses increasing; additionally, there is a little difference in the time-mean intensity of images of the laser stacked by different numbers of sub-pulses. Finally, the obtained results are also given physical explanations.

Modular fuel-cell stack assembly

DOEpatents

Patel, Pinakin [Danbury, CT; Urko, Willam [West Granby, CT

2008-01-29

A modular multi-stack fuel-cell assembly in which the fuel-cell stacks are situated within a containment structure and in which a gas distributor is provided in the structure and distributes received fuel and oxidant gases to the stacks and receives exhausted fuel and oxidant gas from the stacks so as to realize a desired gas flow distribution and gas pressure differential through the stacks. The gas distributor is centrally and symmetrically arranged relative to the stacks so that it itself promotes realization of the desired gas flow distribution and pressure differential.

TESTING FOR CPT VIOLATION IN B^stack">0_{stack">s SEMILEPTONIC DECAYS}

NASA Astrophysics Data System (ADS)

Kooten, R. Van

2014-01-01

A DØ analysis measuring the charge asymmetry A^{stack">b_{stack">sl of like-sign dimuon events due to semileptonic b-hadron decays at the Fermilab Tevatron Collider has shown indications of possible anomalous CP violation in the mixing of neutral B mesons. This result has been used to extract the first senstivity to CPT violation in the Bstack">0stack">s system. An analysis to explore further this anomaly by specifically measuring the semileptonic charge asymmetry, astack">sstack">sl, in Bstack">0stack">s decays is described, as well as how a variant of this analysis can be used to explore a larger set of CPT-violating parameters in the Bstack">0stack">s system for the first time.}}

Characterization of fine-grain piezoceramic stack actuators

NASA Astrophysics Data System (ADS)

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

2001-07-01

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

49 CFR 178.606 - Stacking test.

Code of Federal Regulations, 2010 CFR

2010-10-01

... Testing of Non-bulk Packagings and Packages § 178.606 Stacking test. (a) General. All packaging design... subjected to a force applied to the top surface of the test sample equivalent to the total weight of... non-hazardous liquids with specific gravities different from that of the liquid to be transported, the...

Unified framework to evaluate panmixia and migration direction among multiple sampling locations.

PubMed

Beerli, Peter; Palczewski, Michal

2010-05-01

For many biological investigations, groups of individuals are genetically sampled from several geographic locations. These sampling locations often do not reflect the genetic population structure. We describe a framework using marginal likelihoods to compare and order structured population models, such as testing whether the sampling locations belong to the same randomly mating population or comparing unidirectional and multidirectional gene flow models. In the context of inferences employing Markov chain Monte Carlo methods, the accuracy of the marginal likelihoods depends heavily on the approximation method used to calculate the marginal likelihood. Two methods, modified thermodynamic integration and a stabilized harmonic mean estimator, are compared. With finite Markov chain Monte Carlo run lengths, the harmonic mean estimator may not be consistent. Thermodynamic integration, in contrast, delivers considerably better estimates of the marginal likelihood. The choice of prior distributions does not influence the order and choice of the better models when the marginal likelihood is estimated using thermodynamic integration, whereas with the harmonic mean estimator the influence of the prior is pronounced and the order of the models changes. The approximation of marginal likelihood using thermodynamic integration in MIGRATE allows the evaluation of complex population genetic models, not only of whether sampling locations belong to a single panmictic population, but also of competing complex structured population models.

Improvement in trapped fields by stacking bulk superconductors

NASA Astrophysics Data System (ADS)

Suzuki, A.; Wongsatanawarid, A.; Seki, H.; Murakami, M.

2009-10-01

We studied the effects of stacking several bulk superconductor blocks on the field trapping properties. In order to avoid the detrimental effects of the bottom deteriorated parts, bulk Dy-Ba-Cu-O superconductors 45 mm in diameter and 10 mm in thickness were cut from the top parts of as-grown bulk blocks of 25 mm diameter. We stacked the superconductors and measured the field distribution as a function of the gap. The trapped field measurements were performed by field-cooling the samples inserted in between two permanent magnets with liquid nitrogen. It was found that the trapped field values are almost doubled when the number of stacked bulk superconductors increased from two to three. The present results clearly show that one can expect beneficial effects of increasing the ratio of the height to the diameter even in bulk high temperature superconductors.

High specific power, direct methanol fuel cell stack

DOEpatents

Ramsey, John C [Los Alamos, NM; Wilson, Mahlon S [Los Alamos, NM

2007-05-08

The present invention is a fuel cell stack including at least one direct methanol fuel cell. A cathode manifold is used to convey ambient air to each fuel cell, and an anode manifold is used to convey liquid methanol fuel to each fuel cell. Tie-bolt penetrations and tie-bolts are spaced evenly around the perimeter to hold the fuel cell stack together. Each fuel cell uses two graphite-based plates. One plate includes a cathode active area that is defined by serpentine channels connecting the inlet manifold with an integral flow restrictor to the outlet manifold. The other plate includes an anode active area defined by serpentine channels connecting the inlet and outlet of the anode manifold. Located between the two plates is the fuel cell active region.

The impact of stack geometry and mean pressure on cold end temperature of stack in thermoacoustic refrigeration systems

NASA Astrophysics Data System (ADS)

Wantha, Channarong

2018-02-01

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.

The Direct FuelCell™ stack engineering

NASA Astrophysics Data System (ADS)

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.

Glass transition dynamics of stacked thin polymer films

NASA Astrophysics Data System (ADS)

Fukao, Koji; Terasawa, Takehide; Oda, Yuto; Nakamura, Kenji; Tahara, Daisuke

2011-10-01

The glass transition dynamics of stacked thin films of polystyrene and poly(2-chlorostyrene) were investigated using differential scanning calorimetry and dielectric relaxation spectroscopy. The glass transition temperature Tg of as-stacked thin polystyrene films has a strong depression from that of the bulk samples. However, after annealing at high temperatures above Tg, the stacked thin films exhibit glass transition at a temperature almost equal to the Tg of the bulk system. The α-process dynamics of stacked thin films of poly(2-chlorostyrene) show a time evolution from single-thin-film-like dynamics to bulk-like dynamics during the isothermal annealing process. The relaxation rate of the α process becomes smaller with increase in the annealing time. The time scale for the evolution of the α dynamics during the annealing process is very long compared with that for the reptation dynamics. At the same time, the temperature dependence of the relaxation time for the α process changes from Arrhenius-like to Vogel-Fulcher-Tammann dependence with increase of the annealing time. The fragility index increases and the distribution of the α-relaxation times becomes smaller with increase in the annealing time for isothermal annealing. The observed change in the α process is discussed with respect to the interfacial interaction between the thin layers of stacked thin polymer films.

A stacking method and its applications to Lanzarote tide gauge records

NASA Astrophysics Data System (ADS)

Zhu, Ping; van Ruymbeke, Michel; Cadicheanu, Nicoleta

2009-12-01

A time-period analysis tool based on stacking is introduced in this paper. The original idea comes from the classical tidal analysis method. It is assumed that the period of each major tidal component is precisely determined based on the astronomical constants and it is unchangeable with time at a given point in the Earth. We sum the tidal records at a fixed tidal component center period T then take the mean of it. The stacking could significantly increase the signal-to-noise ratio (SNR) if a certain number of stacking circles is reached. The stacking results were fitted using a sinusoidal function, the amplitude and phase of the fitting curve is computed by the least squares methods. The advantage of the method is that: (1) an individual periodical signal could be isolated by stacking; (2) one can construct a linear Stacking-Spectrum (SSP) by changing the stacking period Ts; (3) the time-period distribution of the singularity component could be approximated by a Sliding-Stacking approach. The shortcoming of the method is that in order to isolate a low energy frequency or separate the nearby frequencies, we need a long enough series with high sampling rate. The method was tested with a numeric series and then it was applied to 1788 days Lanzarote tide gauge records as an example.

Colorimetric stack pad immunoassay for bacterial identification.

PubMed

Eltzov, Evgeni; Marks, Robert S

2017-01-15

A new colorimetric immunoassay concept, utilizing conventional lateral flow membranes (e.g., conjugation, sample, absorption and nitrocellulose), were placed in a different configuration in a stacking manner, where the liquid sample that may contain the analyte diffuses from the bottom to the upper-most layer. The key element of this proprietary technology is a capture layer, where a nitrocellulose membrane is modified with the target analyte of interest, namely in this study target Escherichia coli. During the immunoassay operation, samples contaminated with the target bacteria will conjugate to their corresponding HRP-antibodies laying in wait and the immune-target measurand complex flows by capillarity towards the upper-most layer to generate a colorimetric signal (positive answer) through an enzymatic reaction. In target-free samples, previously immobilized target bacteria on the capture layer will prevent the HRP-labeled anti-target antibodies from migrating to the upper-most layer, where the enzymatic substrate lays in wait. After optimization, the sensitivity of this approach was found to be 1,000 folds higher than ELISAs (10 2 cellsmL -1 ). The advantages of the stacked pad assay include: miniaturization, operational simplicity, fast response time (less than 5min), useful sensitivity. Copyright © 2016 Elsevier B.V. All rights reserved.

Neutron diffraction from aligned stacks of lipid bilayers using the WAND instrument

DOE PAGES

Marquardt, Drew; Frontzek, Matthias D.; Zhao, Yu; ...

2018-02-06

Neutron diffraction from aligned stacks of lipid bilayers is examined using the Wide-Angle Neutron Diffractometer (WAND), located at the High Flux Isotope Reactor, Oak Ridge, Tennessee, USA. Data were collected at different levels of hydration and neutron contrast by varying the relative humidity (RH) and H 2O/D 2O ratio from multi-bilayers of dioleoylphosphatidylcholine and sunflower phosphatidylcholine extract aligned on single-crystal silicon substrates. This work highlights the capabilites of a newly fabricated sample hydration cell, which allows the lipid bilayers to be hydrated with varying H/D ratios from the RH generated by saturated salt solutions, and also demonstrates WAND's capability asmore » an instrument suitable for the study of aligned lipid multi-bilayers.« less

Neutron diffraction from aligned stacks of lipid bilayers using the WAND instrument

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

Marquardt, Drew; Frontzek, Matthias D.; Zhao, Yu

Neutron diffraction from aligned stacks of lipid bilayers is examined using the Wide-Angle Neutron Diffractometer (WAND), located at the High Flux Isotope Reactor, Oak Ridge, Tennessee, USA. Data were collected at different levels of hydration and neutron contrast by varying the relative humidity (RH) and H 2O/D 2O ratio from multi-bilayers of dioleoylphosphatidylcholine and sunflower phosphatidylcholine extract aligned on single-crystal silicon substrates. This work highlights the capabilites of a newly fabricated sample hydration cell, which allows the lipid bilayers to be hydrated with varying H/D ratios from the RH generated by saturated salt solutions, and also demonstrates WAND's capability asmore » an instrument suitable for the study of aligned lipid multi-bilayers.« less

[Analysis on Mechanism of Rainout Carried by Wet Stack of Thermal Power Plant].

PubMed

Ouyang, Li-hua; Zhuang, Ye; Liu, Ke-wei; Chen, Zhen-yu; Gu, Peng

2015-06-01

Rainout from wet-stack took placed in many thermal power plants with WFGD system. Research on causes of the rainout is important to solve the problem. The objective of this research is to analyze the mechanism of rainout. Field study was performed to collect experimental data in one thermal power plant, including the amount of desulfurization slurry carried by wet flue gas, liquor condensate from wet duct, and droplets from the wet stack. Source apportionment analysis was carried out based on physical and chemical data of liquid sample and solid sample. The result showed that mist eliminator operated well, which met the performance guarantee value. But the total amount of desulfurization slurry in flue gas and the sulfate concentration in liquid condensate discharge from the wet duct/stack increased. The liquid condensate accumulated in the wet duct/stack led to liquid re-entrainment. In conclusion, the rainout in this power plant was caused by the short of wet ductwork or liquid discharge system, the droplets caused by re-entrainment carried by the saturated gas released from the stack. The main undissolved components of the rainout were composite carbonate and aluminosilicate. Although ash concentration in this WFGD met the regulation criteria, source apportionment analysis showed that fly ash contributed to rainout was accounted for 60%. This percentage value was same as the data of solid particles in the condensate. It is important to optimize the wet ductwork, wet stack liner, liquid collectors and drainage. Avoiding the accumulation from saturated vapor thermal condensation is an effective way to solve the wet stack rainout.

40 CFR 761.283 - Determination of the number of samples to collect and sample collection locations.

Code of Federal Regulations, 2012 CFR

2012-07-01

... sites at this example location: a loading dock, a transformer storage lot, and a disposal pit. The... (three samples). The non-liquid PCB remediation wastes present at the transformer storage lot are oily...

40 CFR 761.283 - Determination of the number of samples to collect and sample collection locations.

Code of Federal Regulations, 2010 CFR

2010-07-01

... sites at this example location: a loading dock, a transformer storage lot, and a disposal pit. The... (three samples). The non-liquid PCB remediation wastes present at the transformer storage lot are oily...

Dynamic Stacking Pathway of Perylene Dimers in Aromatic and Nonaromatic Solvents.

PubMed

Hollfelder, Manuel; Gekle, Stephan

2015-08-13

Using molecular dynamics simulations, we elucidate in detail the dynamics of the π-π stacking process of a perylene bisimide (PBI) dimer solvated in toluene. Our calculations show that the transition from the open (unstacked) to the stacked configuration is hindered by a small free energy barrier of approximately 1kBT in toluene but not in the nonaromatic solvent hexane. A similar effect is observed tor two non-covalently linked monomers. The origin of this barrier is traced back to π-π interactions between perylene and the aromatic solvent which are very similar in nature to those between two PBI monomers. The stacking process proceeds in three phases via two well-defined transition states: (i) in the first phase, the two PBI molecules share part of their respective solvation shells forming the first transition state. Further approach needs to squeeze out the shared solvent layer, thus creating the energy barrier. (ii) After removal of the separating solvent, the two PBIs form a second transition state with one monomer located at a random position in the other's solvation shell. (iii) Finally, the two PBIs slide on top of each other into their final stacked position.

Highly sensitive oligosaccharide analysis in capillary electrophoresis using large-volume sample stacking with an electroosmotic flow pump.

PubMed

Kawai, Takayuki; Watanabe, Masato; Sueyoshi, Kenji; Kitagawa, Fumihiko; Otsuka, Koji

2012-04-06

To obtain high sensitivity in capillary electrophoresis of oligosaccharide without reducing the high resolution with an easy experimental procedure, large-volume sample stacking with an electroosmotic flow pump (LVSEP) was investigated. As a fundamental study, effect of the conductivity of a sample solution in LVSEP was examined. It was revealed that LVSEP was successfully carried out even in using a sample solution with the ionic strength of 150 μM and the conductivity ratio of 20, indicating a good applicability of LVSEP to the analysis of real samples containing salts. When glucose oligomer was analyzed as a model sample in LVSEP-capillary zone electrophoresis (CZE), all peaks were well resolved with decreasing only 5% of the peak-to-peak distance, which suggested 95% of the whole capillary could be used for the effective separation. In the analysis of maltoheptaose, a good calibration line with correlation coefficient of 0.9995 was obtained. The limit of detection was estimated as 2 pM, which was 500-fold lower than that in the conventional CZE. N-linked glycans released from three glycoproteins, bovine ribonuclease B, bovine fetuin, and human α(1)-acid glycoprotein were also analyzed by LVSEP-CZE. By the sample purification with a gel filtration column, further sample dilution to reduce the sample conductivity for LVSEP was not needed. All glycan samples were well concentrated and separated with up to a 770-fold sensitivity increase. The run-to-run repeatabilities of the migration time, peak height, and peak area were good with relative standard deviations of 0.1-1.3%, 1.2-1.7%, and 2.8-4.9%, respectively. Copyright © 2011 Elsevier B.V. All rights reserved.

Layer Number and Stacking Order Imaging of Few-layer Graphenes by Transmission Electron Microscopy

NASA Astrophysics Data System (ADS)

Ping, Jinglei; Fuhrer, Michael

2012-02-01

A method using transmission electron microscopy (TEM) selected area electron diffraction (SAED) patterns and dark field (DF) images is developed to identify graphene layer number and stacking order by comparing intensity ratios of SAED spots with theory. Graphene samples are synthesized by ambient pressure chemical vapor depostion and then etched by hydrogen in high temperature to produce samples with crystalline stacking but varying layer number on the nanometer scale. Combined DF images from first- and second-order diffraction spots are used to produce images with layer-number and stacking-order contrast with few-nanometer resolution. This method is proved to be accurate enough for quantative stacking-order-identification of graphenes up to at least four layers. This work was partially supported by Science of Precision Multifunctional Nanostructures for Elecrical Energy Storage, an Energy Frontier Research Center funded by the U.S. DOE, Office of Science, Office of Basic Energy Sciences under Award Number DESC0001160.

ooi: OpenStack OCCI interface

NASA Astrophysics Data System (ADS)

López García, Álvaro; Fernández del Castillo, Enol; Orviz Fernández, Pablo

In this document we present an implementation of the Open Grid Forum's Open Cloud Computing Interface (OCCI) for OpenStack, namely ooi (Openstack occi interface, 2015) [1]. OCCI is an open standard for management tasks over cloud resources, focused on interoperability, portability and integration. ooi aims to implement this open interface for the OpenStack cloud middleware, promoting interoperability with other OCCI-enabled cloud management frameworks and infrastructures. ooi focuses on being non-invasive with a vanilla OpenStack installation, not tied to a particular OpenStack release version.

Remaining Sites Verification Package for the 100-F-46, 119-F Stack Sampling French Drain, Waste Site Reclassification Form 2008-021

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

J. M. Capron

2008-08-08

The 100-F-46 french drain consisted of a 1.5 to 3 m long, vertically buried, gravel-filled pipe that was approximately 1 m in diameter. Also included in this waste site was a 5 cm cast-iron pipeline that drained condensate from the 119-F Stack Sampling Building into the 100-F-46 french drain. In accordance with this evaluation, the confirmatory sampling results support a reclassification of this site to No Action. The current site conditions achieve the remedial action objectives and the corresponding remedial action goals established in the Remaining Sites ROD. The results of confirmatory sampling show that residual contaminant concentrations do notmore » preclude any future uses and allow for unrestricted use of shallow zone soils. The results also demonstrate that residual contaminant concentrations are protective of groundwater and the Columbia River.« less

Energy Expenditure of Sport Stacking

ERIC Educational Resources Information Center

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

2009-01-01

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…

Stacking-dependent interlayer coupling in trilayer MoS 2 with broken inversion symmetry

DOE PAGES

Yan, Jiaxu; Wang, Xingli; Tay, Beng Kang; ...

2015-11-13

The stacking configuration in few-layer two-dimensional (2D) materials results in different structural symmetries and layer-to-layer interactions, and hence it provides a very useful parameter for tuning their electronic properties. For example, ABA-stacking trilayer graphene remains semimetallic similar to that of monolayer, while ABC-stacking is predicted to be a tunable band gap semiconductor under an external electric field. Such stacking dependence resulting from many-body interactions has recently been the focus of intense research activities. Here we demonstrate that few-layer MoS 2 samples grown by chemical vapor deposition with different stacking configurations (AA, AB for bilayer; AAB, ABB, ABA, AAA for trilayer)more » exhibit distinct coupling phenomena in both photoluminescence and Raman spectra. By means of ultralow-frequency (ULF) Raman spectroscopy, we demonstrate that the evolution of interlayer interaction with various stacking configurations correlates strongly with layer-breathing mode (LBM) vibrations. Our ab initio calculations reveal that the layer-dependent properties arise from both the spin–orbit coupling (SOC) and interlayer coupling in different structural symmetries. Lastly, such detailed understanding provides useful guidance for future spintronics fabrication using various stacked few-layer MoS 2 blocks.« less

Stacking-dependent interlayer coupling in trilayer MoS 2 with broken inversion symmetry

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

Yan, Jiaxu; Wang, Xingli; Tay, Beng Kang

The stacking configuration in few-layer two-dimensional (2D) materials results in different structural symmetries and layer-to-layer interactions, and hence it provides a very useful parameter for tuning their electronic properties. For example, ABA-stacking trilayer graphene remains semimetallic similar to that of monolayer, while ABC-stacking is predicted to be a tunable band gap semiconductor under an external electric field. Such stacking dependence resulting from many-body interactions has recently been the focus of intense research activities. Here we demonstrate that few-layer MoS 2 samples grown by chemical vapor deposition with different stacking configurations (AA, AB for bilayer; AAB, ABB, ABA, AAA for trilayer)more » exhibit distinct coupling phenomena in both photoluminescence and Raman spectra. By means of ultralow-frequency (ULF) Raman spectroscopy, we demonstrate that the evolution of interlayer interaction with various stacking configurations correlates strongly with layer-breathing mode (LBM) vibrations. Our ab initio calculations reveal that the layer-dependent properties arise from both the spin–orbit coupling (SOC) and interlayer coupling in different structural symmetries. Lastly, such detailed understanding provides useful guidance for future spintronics fabrication using various stacked few-layer MoS 2 blocks.« less

Measurement of heat conduction through stacked screens

NASA Technical Reports Server (NTRS)

Lewis, M. A.; Kuriyama, T.; Kuriyama, F.; Radebaugh, R.

1998-01-01

This paper describes the experimental apparatus for the measurement of heat conduction through stacked screens as well as some experimental results taken with the apparatus. Screens are stacked in a fiberglass-epoxy cylinder, which is 24.4 mm in diameter and 55 mm in length. The cold end of the stacked screens is cooled by a Gifford-McMahon (GM) cryocooler at cryogenic temperature, and the hot end is maintained at room temperature. Heat conduction through the screens is determined from the temperature gradient in a calibrated heat flow sensor mounted between the cold end of the stacked screens and the GM cryocooler. The samples used for these experiments consisted of 400-mesh stainless steel screens, 400-mesh phosphor bronze screens, and two different porosities of 325-mesh stainless steel screens. The wire diameter of the 400-mesh stainless steel and phosphor bronze screens was 25.4 micrometers and the 325-mesh stainless steel screen wire diameters were 22.9 micrometers and 27.9 micrometers. Standard porosity values were used for the experimental data with additional porosity values used on selected experiments. The experimental results showed that the helium gas between each screen enhanced the heat conduction through the stacked screens by several orders of magnitude compared to that in vacuum. The conduction degradation factor is the ratio of actual heat conduction to the heat conduction where the regenerator material is assumed to be a solid rod of the same cross sectional area as the metal fraction of the screen. This factor was about 0.1 for the stainless steel and 0.022 for the phosphor bronze, and almost constant for the temperature range of 40 to 80 K at the cold end.

Measurement of heat conduction through stacked screens.

PubMed

Lewis, M A; Kuriyama, T; Kuriyama, F; Radebaugh, R

1998-01-01

This paper describes the experimental apparatus for the measurement of heat conduction through stacked screens as well as some experimental results taken with the apparatus. Screens are stacked in a fiberglass-epoxy cylinder, which is 24.4 mm in diameter and 55 mm in length. The cold end of the stacked screens is cooled by a Gifford-McMahon (GM) cryocooler at cryogenic temperature, and the hot end is maintained at room temperature. Heat conduction through the screens is determined from the temperature gradient in a calibrated heat flow sensor mounted between the cold end of the stacked screens and the GM cryocooler. The samples used for these experiments consisted of 400-mesh stainless steel screens, 400-mesh phosphor bronze screens, and two different porosities of 325-mesh stainless steel screens. The wire diameter of the 400-mesh stainless steel and phosphor bronze screens was 25.4 micrometers and the 325-mesh stainless steel screen wire diameters were 22.9 micrometers and 27.9 micrometers. Standard porosity values were used for the experimental data with additional porosity values used on selected experiments. The experimental results showed that the helium gas between each screen enhanced the heat conduction through the stacked screens by several orders of magnitude compared to that in vacuum. The conduction degradation factor is the ratio of actual heat conduction to the heat conduction where the regenerator material is assumed to be a solid rod of the same cross sectional area as the metal fraction of the screen. This factor was about 0.1 for the stainless steel and 0.022 for the phosphor bronze, and almost constant for the temperature range of 40 to 80 K at the cold end.

Stack gas treatment

DOEpatents

Reeves, Adam A.

1977-04-12

Hot stack gases transfer contained heat to a gravity flow of pebbles treated with a catalyst, cooled stacked gases and a sulfuric acid mist is withdrawn from the unit, and heat picked up by the pebbles is transferred to air for combustion or other process. The sulfuric acid (or sulfur, depending on the catalyst) is withdrawn in a recovery unit.

Pressurized electrolysis stack with thermal expansion capability

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

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, themore » 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.« less

Effects of stacking sequence on impact damage resistance and residual strength for quasi-isotropic laminates

NASA Technical Reports Server (NTRS)

Dost, Ernest F.; Ilcewicz, Larry B.; Avery, William B.; Coxon, Brian R.

1991-01-01

Residual strength of an impacted composite laminate is dependent on details of the damage state. Stacking sequence was varied to judge its effect on damage caused by low-velocity impact. This was done for quasi-isotropic layups of a toughened composite material. Experimental observations on changes in the impact damage state and postimpact compressive performance were presented for seven different laminate stacking sequences. The applicability and limitations of analysis compared to experimental results were also discussed. Postimpact compressive behavior was found to be a strong function of the laminate stacking sequence. This relationship was found to depend on thickness, stacking sequence, size, and location of sublaminates that comprise the impact damage state. The postimpact strength for specimens with a relatively symmetric distribution of damage through the laminate thickness was accurately predicted by models that accounted for sublaminate stability and in-plane stress redistribution. An asymmetric distribution of damage in some laminate stacking sequences tended to alter specimen stability. Geometrically nonlinear finite element analysis was used to predict this behavior.

Temperature dependent photoluminescence and micromapping of multiple stacks InAs quantum dots

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

Xu, Ming, E-mail: ming.xu@lgep.supelec.fr; Jaffré, Alexandre, E-mail: ming.xu@lgep.supelec.fr; Alvarez, José, E-mail: ming.xu@lgep.supelec.fr

2015-02-27

We utilized temperature dependent photoluminescence (PL) techniques to investigate 1, 3 and 5 stack InGaAs quantum dots (QDs) grown on cross-hatch patterns. PL mapping can well reproduce the QDs distribution as AFM and position dependency of QD growth. It is possible to observe crystallographic dependent PL. The temperature dependent spectra exhibit the QDs energy distribution which reflects the size and shape. The inter-dot carrier coupling effect is observed and translated as a red shift of 120mV on the [1–10] direction peak is observed at 30K on 1 stack with regards to 3 stacks samples, which is assigned to lateral coupling.

Interface band alignment in high-k gate stacks

NASA Astrophysics Data System (ADS)

Eric, Bersch; Hartlieb, P.

2005-03-01

In order to successfully implement alternate high-K dielectric materials into MOS structures, the interface properties of MOS gate stacks must be better understood. Dipoles that may form at the metal/dielectric and dielectric/semiconductor interfaces make the band offsets difficult to predict. We have measured the conduction and valence band densities of states for a variety MOS stacks using in situ using inverse photoemission (IPE) and photoemission spectroscopy (PES), respectively. Results obtained from clean and metallized (with Ru or Al) HfO2/Si, SiO2/Si and mixed silicate films will be presented. IPE indicates a shift of the conduction band minimum (CBM) to higher energy (i.e. away from EF) with increasing SiO2. The effect of metallization on the location of band edges depends upon the metal species. The addition of N to the dielectrics shifts the CBM in a way that is thickness dependent. Possible mechanisms for these observed effects will be discussed.

Seismic data enhancement and regularization using finite offset Common Diffraction Surface (CDS) stack

NASA Astrophysics Data System (ADS)

Garabito, German; Cruz, João Carlos Ribeiro; Oliva, Pedro Andrés Chira; Söllner, Walter

2017-01-01

The Common Reflection Surface stack is a robust method for simulating zero-offset and common-offset sections with high accuracy from multi-coverage seismic data. For simulating common-offset sections, the Common-Reflection-Surface stack method uses a hyperbolic traveltime approximation that depends on five kinematic parameters for each selected sample point of the common-offset section to be simulated. The main challenge of this method is to find a computationally efficient data-driven optimization strategy for accurately determining the five kinematic stacking parameters on which each sample of the stacked common-offset section depends. Several authors have applied multi-step strategies to obtain the optimal parameters by combining different pre-stack data configurations. Recently, other authors used one-step data-driven strategies based on a global optimization for estimating simultaneously the five parameters from multi-midpoint and multi-offset gathers. In order to increase the computational efficiency of the global optimization process, we use in this paper a reduced form of the Common-Reflection-Surface traveltime approximation that depends on only four parameters, the so-called Common Diffraction Surface traveltime approximation. By analyzing the convergence of both objective functions and the data enhancement effect after applying the two traveltime approximations to the Marmousi synthetic dataset and a real land dataset, we conclude that the Common-Diffraction-Surface approximation is more efficient within certain aperture limits and preserves at the same time a high image accuracy. The preserved image quality is also observed in a direct comparison after applying both approximations for simulating common-offset sections on noisy pre-stack data.

Lightweight Stacks of Direct Methanol Fuel Cells

NASA Technical Reports Server (NTRS)

Narayanan, Sekharipuram; Valdez, Thomas

2004-01-01

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.

Cathodoluminescence of stacking fault bound excitons for local probing of the exciton diffusion length in single GaN nanowires

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

Nogues, Gilles, E-mail: gilles.nogues@neel.cnrs.fr; Den Hertog, Martien; Inst. NEEL, CNRS, F-38042 Grenoble

We perform correlated studies of individual GaN nanowires in scanning electron microscopy combined to low temperature cathodoluminescence, microphotoluminescence, and scanning transmission electron microscopy. We show that some nanowires exhibit well localized regions emitting light at the energy of a stacking fault bound exciton (3.42 eV) and are able to observe the presence of a single stacking fault in these regions. Precise measurements of the cathodoluminescence signal in the vicinity of the stacking fault give access to the exciton diffusion length near this location.

Hamiltonian approach to slip-stacking dynamics

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

Lee, S. Y.; Ng, K. Y.

Hamiltonian dynamics has been applied to study the slip-stacking dynamics. The canonical-perturbation method is employed to obtain the second-harmonic correction term in the slip-stacking Hamiltonian. The Hamiltonian approach provides a clear optimal method for choosing the slip-stacking parameter and improving stacking efficiency. The dynamics are applied specifically to the Fermilab Booster-Recycler complex. As a result, the dynamics can also be applied to other accelerator complexes.

Hamiltonian approach to slip-stacking dynamics

DOE PAGES

Lee, S. Y.; Ng, K. Y.

2017-06-29

Hamiltonian dynamics has been applied to study the slip-stacking dynamics. The canonical-perturbation method is employed to obtain the second-harmonic correction term in the slip-stacking Hamiltonian. The Hamiltonian approach provides a clear optimal method for choosing the slip-stacking parameter and improving stacking efficiency. The dynamics are applied specifically to the Fermilab Booster-Recycler complex. As a result, the dynamics can also be applied to other accelerator complexes.

Fast and sensitive method to determine parabens by capillary electrophoresis using automatic reverse electrode polarity stacking mode: application to hair samples.

PubMed

Sako, Alysson V F; Dolzan, Maressa D; Micke, Gustavo Amadeu

2015-09-01

This paper describes a fast and sensitive method for the determination of methyl, ethyl, propyl, and butylparaben in hair samples by capillary electrophoresis using automatic reverse electrode polarity stacking mode. In the proposed method, solutions are injected using the flush command of the analysis software (940 mbar) and the polarity switching is carried out automatically immediately after the sample injection. The advantages compared with conventional stacking methods are the increased analytical frequency, repeatability, and inter-day precision. All analyses were performed in a fused silica capillary (50 cm, 41.5 cm in effective length, 50 μm i.d.), and the background electrolyte was composed of 20 mmol L(-1) sodium tetraborate in 10 % of methanol, pH 9.3. For the reverse polarity, -25 kV/35 s was applied followed by application of +30 kV for the electrophoretic run. Temperature was set at 20 °C, and all analytes were monitored at 297 nm. The method showed acceptable linearity (r (2) > 0.997) in the studied range of 0.1-5.0 mg L(-1), limits of detection below 0.017 mg L(-1), and inter-day, intra-day, and instrumental precision better than 6.2, 3.6, and 4.6 %, respectively. Considering parabens is widely used as a preservative in many products and the reported possibility of damage to the hair and also to human health caused by these compounds, the proposed method was applied to evaluate the adsorption of parabens in hair samples. The results indicate that there is a greater adsorption of methylparaben compared to the other parabens tested and also dyed hairs had a greater adsorption capacity for parabens than natural hairs.

SRB Stack Training

NASA Image and Video Library

2018-01-30

Crane operators and ground support personnel practice lifting and stacking mock-ups of solid rocket booster (SRB) segments in High Bay 4 inside the Vehicle Assembly Building at NASA’s Kennedy Space Center in Florida. The training will help workers prepare for SRB stacking operations for the agency's Space Launch System SLS) rocket. The SLS will launch the Orion spacecraft on its first integrated flight, Exploration Mission-1.

Sampling for Air Chemical Emissions from the Life Sciences Laboratory II

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

Ballinger, Marcel Y.; Lindberg, Michael J.

Sampling for air chemical emissions from the Life Science Laboratory II (LSL-II) ventilation stack was performed in an effort to determine potential exposure of maintenance staff to laboratory exhaust on the building roof. The concern about worker exposure was raised in December 2015 and several activities were performed to assist in estimating exposure concentrations. Data quality objectives were developed to determine the need for and scope and parameters of a sampling campaign to measure chemical emissions from research and development activities to the outside air. The activities provided data on temporal variation of air chemical concentrations and a basis formore » evaluating calculated emissions. Sampling for air chemical emissions was performed in the LSL-II ventilation stack over the 6-week period from July 26 to September 1, 2016. A total of 12 sampling events were carried out using 16 sample media. Resulting analysis provided concentration data on 49 analytes. All results were below occupational exposure limits and most results were below detection limits. When compared to calculated emissions, only 5 of the 49 chemicals had measured concentrations greater than predicted. This sampling effort will inform other study components to develop a more complete picture of a worker’s potential exposure from LSL-II rooftop activities. Mixing studies were conducted to inform spatial variation in concentrations at other rooftop locations and can be used in conjunction with these results to provide temporal variations in concentrations for estimating the potential exposure to workers working in and around the LSL-II stack.« less

Determining Optimal Location and Numbers of Sample Transects for Characterization of UXO Sites

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

BILISOLY, ROGER L.; MCKENNA, SEAN A.

2003-01-01

Previous work on sample design has been focused on constructing designs for samples taken at point locations. Significantly less work has been done on sample design for data collected along transects. A review of approaches to point and transect sampling design shows that transects can be considered as a sequential set of point samples. Any two sampling designs can be compared through using each one to predict the value of the quantity being measured on a fixed reference grid. The quality of a design is quantified in two ways: computing either the sum or the product of the eigenvalues ofmore » the variance matrix of the prediction error. An important aspect of this analysis is that the reduction of the mean prediction error variance (MPEV) can be calculated for any proposed sample design, including one with straight and/or meandering transects, prior to taking those samples. This reduction in variance can be used as a ''stopping rule'' to determine when enough transect sampling has been completed on the site. Two approaches for the optimization of the transect locations are presented. The first minimizes the sum of the eigenvalues of the predictive error, and the second minimizes the product of these eigenvalues. Simulated annealing is used to identify transect locations that meet either of these objectives. This algorithm is applied to a hypothetical site to determine the optimal locations of two iterations of meandering transects given a previously existing straight transect. The MPEV calculation is also used on both a hypothetical site and on data collected at the Isleta Pueblo to evaluate its potential as a stopping rule. Results show that three or four rounds of systematic sampling with straight parallel transects covering 30 percent or less of the site, can reduce the initial MPEV by as much as 90 percent. The amount of reduction in MPEV can be used as a stopping rule, but the relationship between MPEV and the results of excavation versus no

Helping Students Design HyperCard Stacks.

ERIC Educational Resources Information Center

Dunham, Ken

1995-01-01

Discusses how to teach students to design HyperCard stacks. Highlights include introducing HyperCard, developing storyboards, introducing design concepts and scripts, presenting stacks, evaluating storyboards, and continuing projects. A sidebar presents a HyperCard stack evaluation form. (AEF)

40 CFR 75.72 - Determination of NOX mass emissions for common stack and multiple stack configurations.

Code of Federal Regulations, 2010 CFR

2010-07-01

... the hourly stack flow rate (in scfh). Only one methodology for determining NOX mass emissions shall be...-diluent continuous emissions monitoring system and a flow monitoring system in the common stack, record... maintain a flow monitoring system and diluent monitor in the duct to the common stack from each unit; or...

Modular fuel-cell stack assembly

DOEpatents

Patel, Pinakin

2010-07-13

A fuel cell assembly having a plurality of fuel cells arranged in a stack. An end plate assembly abuts the fuel cell at an end of said stack. The end plate assembly has an inlet area adapted to receive an exhaust gas from the stack, an outlet area and a passage connecting the inlet area and outlet area and adapted to carry the exhaust gas received at the inlet area from the inlet area to the outlet area. A further end plate assembly abuts the fuel cell at a further opposing end of the stack. The further end plate assembly has a further inlet area adapted to receive a further exhaust gas from the stack, a further outlet area and a further passage connecting the further inlet area and further outlet area and adapted to carry the further exhaust gas received at the further inlet area from the further inlet area to the further outlet area.

Guanine base stacking in G-quadruplex nucleic acids

PubMed Central

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

2013-01-01

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

Development of a New Microextraction Fiber Combined to On-Line Sample Stacking Capillary Electrophoresis UV Detection for Acidic Drugs Determination in Real Water Samples.

PubMed

Espina-Benitez, Maria; Araujo, Lilia; Prieto, Avismelsi; Navalón, Alberto; Vílchez, José Luis; Valera, Paola; Zambrano, Ana; Dugas, Vincent

2017-07-07

A new analytical method coupling a (off-line) solid-phase microextraction with an on-line capillary electrophoresis (CE) sample enrichment technique was developed for the analysis of ketoprofen, naproxen and clofibric acid from water samples, which are known as contaminants of emerging concern in aquatic environments. New solid-phase microextraction fibers based on physical coupling of chromatographic supports onto epoxy glue coated needle were studied for the off-line preconcentration of these micropollutants. Identification and quantification of such acidic drugs were done by capillary zone electrophoresis (CZE) using ultraviolet diode array detection (DAD). Further enhancement of concentration sensitivity detection was achieved by on-line CE "acetonitrile stacking" preconcentration technique. Among the eight chromatographic supports investigated, Porapak Q sorbent showed higher extraction and preconcentration capacities. The screening of parameters that influence the microextraction process was carried out using a two-level fractional factorial. Optimization of the most relevant parameters was then done through a surface response three-factor Box-Behnken design. The limits of detection and limits of quantification for the three drugs ranged between 0.96 and 1.27 µg∙L -1 and 2.91 and 3.86 µg∙L -1 , respectively. Recovery yields of approximately 95 to 104% were measured. The developed method is simple, precise, accurate, and allows quantification of residues of these micropollutants in Genil River water samples using inexpensive fibers.

Rapid and Nondestructive Identification of Polytypism and Stacking Sequences in Few-Layer Molybdenum Diselenide by Raman Spectroscopy

DOE PAGES

Lu, Xin; Utama, M. Iqbal Bakti; Lin, Junhao; ...

2015-07-02

Various combinations of interlayer shear modes emerge in few-layer molybdenum diselenide grown by chemical vapor deposition depending on the stacking configuration of the sample. Raman measurements may also reveal polytypism and stacking faults, as supported by first principles calculations and high-resolution transmission electron microscopy. Thus, Raman spectroscopy is an important tool in probing stacking-dependent properties in few-layer 2D materials.

Gas dispersion concentration of trace inorganic contaminants from fuel gas and analysis using head-column field-amplified sample stacking capillary electrophoresis.

PubMed

Yang, Jianmin; Li, Hai-Fang; Li, Meilan; Lin, Jin-Ming

2012-08-21

The presence of inorganic elements in fuel gas generally accelerates the corrosion and depletion of materials used in the fuel gas industry, and even leads to serious accidents. For identification of existing trace inorganic contaminants in fuel gas in a portable way, a highly efficient gas-liquid sampling collection system based on gas dispersion concentration is introduced in this work. Using the constructed dual path gas-liquid collection setup, inorganic cations and anions were simultaneously collected from real liquefied petroleum gas (LPG) and analyzed by capillary electrophoresis (CE) with indirect UV absorbance detection. The head-column field-amplified sample stacking technique was applied to improve the detection limits to 2-25 ng mL(-1). The developed collection and analytical methods have successfully determined existing inorganic contaminants in a real LPG sample in the range of 4.59-138.69 μg m(-3). The recoveries of cations and anions with spiked LPG samples were between 83.98 and 105.63%, and the relative standard deviations (RSDs) were less than 7.19%.

Variable density randomized stack of spirals (VDR-SoS) for compressive sensing MRI.

PubMed

Valvano, Giuseppe; Martini, Nicola; Landini, Luigi; Santarelli, Maria Filomena

2016-07-01

To develop a 3D sampling strategy based on a stack of variable density spirals for compressive sensing MRI. A random sampling pattern was obtained by rotating each spiral by a random angle and by delaying for few time steps the gradient waveforms of the different interleaves. A three-dimensional (3D) variable sampling density was obtained by designing different variable density spirals for each slice encoding. The proposed approach was tested with phantom simulations up to a five-fold undersampling factor. Fully sampled 3D dataset of a human knee, and of a human brain, were obtained from a healthy volunteer. The proposed approach was tested with off-line reconstructions of the knee dataset up to a four-fold acceleration and compared with other noncoherent trajectories. The proposed approach outperformed the standard stack of spirals for various undersampling factors. The level of coherence and the reconstruction quality of the proposed approach were similar to those of other trajectories that, however, require 3D gridding for the reconstruction. The variable density randomized stack of spirals (VDR-SoS) is an easily implementable trajectory that could represent a valid sampling strategy for 3D compressive sensing MRI. It guarantees low levels of coherence without requiring 3D gridding. Magn Reson Med 76:59-69, 2016. © 2015 Wiley Periodicals, Inc. © 2015 Wiley Periodicals, Inc.

An evaluation of potential sampling locations in a reservoir with emphasis on conserved spatial correlation structure.

PubMed

Yenilmez, Firdes; Düzgün, Sebnem; Aksoy, Aysegül

2015-01-01

In this study, kernel density estimation (KDE) was coupled with ordinary two-dimensional kriging (OK) to reduce the number of sampling locations in measurement and kriging of dissolved oxygen (DO) concentrations in Porsuk Dam Reservoir (PDR). Conservation of the spatial correlation structure in the DO distribution was a target. KDE was used as a tool to aid in identification of the sampling locations that would be removed from the sampling network in order to decrease the total number of samples. Accordingly, several networks were generated in which sampling locations were reduced from 65 to 10 in increments of 4 or 5 points at a time based on kernel density maps. DO variograms were constructed, and DO values in PDR were kriged. Performance of the networks in DO estimations were evaluated through various error metrics, standard error maps (SEM), and whether the spatial correlation structure was conserved or not. Results indicated that smaller number of sampling points resulted in loss of information in regard to spatial correlation structure in DO. The minimum representative sampling points for PDR was 35. Efficacy of the sampling location selection method was tested against the networks generated by experts. It was shown that the evaluation approach proposed in this study provided a better sampling network design in which the spatial correlation structure of DO was sustained for kriging.

A comparison of temporal and location-based sampling strategies for global positioning system-triggered electronic diaries.

PubMed

Törnros, Tobias; Dorn, Helen; Reichert, Markus; Ebner-Priemer, Ulrich; Salize, Hans-Joachim; Tost, Heike; Meyer-Lindenberg, Andreas; Zipf, Alexander

2016-11-21

Self-reporting is a well-established approach within the medical and psychological sciences. In order to avoid recall bias, i.e. past events being remembered inaccurately, the reports can be filled out on a smartphone in real-time and in the natural environment. This is often referred to as ambulatory assessment and the reports are usually triggered at regular time intervals. With this sampling scheme, however, rare events (e.g. a visit to a park or recreation area) are likely to be missed. When addressing the correlation between mood and the environment, it may therefore be beneficial to include participant locations within the ambulatory assessment sampling scheme. Based on the geographical coordinates, the database query system then decides if a self-report should be triggered or not. We simulated four different ambulatory assessment sampling schemes based on movement data (coordinates by minute) from 143 voluntary participants tracked for seven consecutive days. Two location-based sampling schemes incorporating the environmental characteristics (land use and population density) at each participant's location were introduced and compared to a time-based sampling scheme triggering a report on the hour as well as to a sampling scheme incorporating physical activity. We show that location-based sampling schemes trigger a report less often, but we obtain more unique trigger positions and a greater spatial spread in comparison to sampling strategies based on time and distance. Additionally, the location-based methods trigger significantly more often at rarely visited types of land use and less often outside the study region where no underlying environmental data are available.

Flexible interconnects for fuel cell stacks

DOEpatents

Lenz, David J.; Chung, Brandon W.; Pham, Ai Quoc

2004-11-09

An interconnect that facilitates electrical connection and mechanical support with minimal mechanical stress for fuel cell stacks. The interconnects are flexible and provide mechanically robust fuel cell stacks with higher stack performance at lower cost. The flexible interconnects replace the prior rigid rib interconnects with flexible "fingers" or contact pads which will accommodate the imperfect flatness of the ceramic fuel cells. Also, the mechanical stress of stacked fuel cells will be smaller due to the flexibility of the fingers. The interconnects can be one-sided or double-sided.

Joint Inversion of Source Location and Source Mechanism of Induced Microseismics

NASA Astrophysics Data System (ADS)

Liang, C.

2014-12-01

Seismic source mechanism is a useful property to indicate the source physics and stress and strain distribution in regional, local and micro scales. In this study we jointly invert source mechanisms and locations for microseismics induced in fluid fracturing treatment in the oil and gas industry. For the events that are big enough to see waveforms, there are quite a few techniques can be applied to invert the source mechanism including waveform inversion, first polarity inversion and many other methods and variants based on these methods. However, for events that are too small to identify in seismic traces such as the microseismics induced by the fluid fracturing in the Oil and Gas industry, a source scanning algorithms (SSA for short) with waveform stacking are usually applied. At the same time, a joint inversion of location and source mechanism are possible but at a cost of high computation budget. The algorithm is thereby called Source Location and Mechanism Scanning Algorithm, SLMSA for short. In this case, for given velocity structure, all possible combinations of source locations (X,Y and Z) and source mechanism (Strike, Dip and Rake) are used to compute travel-times and polarities of waveforms. Correcting Normal moveout times and polarities, and stacking all waveforms, the (X, Y, Z , strike, dip, rake) combination that gives the strongest stacking waveform is identified as the solution. To solve the problem of high computation problem, CPU-GPU programing is applied. Numerical datasets are used to test the algorithm. The SLMSA has also been applied to a fluid fracturing datasets and reveal several advantages against the location only method: (1) for shear sources, the source only program can hardly locate them because of the canceling out of positive and negative polarized traces, but the SLMSA method can successfully pick up those events; (2) microseismic locations alone may not be enough to indicate the directionality of micro-fractures. The statistics of

CFD modelling of sampling locations for early detection of spontaneous combustion in long-wall gob areas.

PubMed

Yuan, Liming; Smith, Alex C

In this study, computational fluid dynamics (CFD) modeling was conducted to optimize gas sampling locations for the early detection of spontaneous heating in longwall gob areas. Initial simulations were carried out to predict carbon monoxide (CO) concentrations at various regulators in the gob using a bleeder ventilation system. Measured CO concentration values at these regulators were then used to calibrate the CFD model. The calibrated CFD model was used to simulate CO concentrations at eight sampling locations in the gob using a bleederless ventilation system to determine the optimal sampling locations for early detection of spontaneous combustion.

Review of Stack CSP Technologies

NASA Technical Reports Server (NTRS)

Ghaffarian, R.

1999-01-01

CSP is an emerging technology with significant potential growth in stacking. Many of the stacking techniques for conventional packages could be implemented for CSP once materials, process, and system development for finer features are developed.

Mercury Dispersion Modeling And Purge Ventilation Stack Height Determination For Tank 40H

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

Rivera-Giboyeaux, A.

2017-05-19

The SRNL Atmospheric Technologies Group performed an analysis for mercury emissions from H-Tank Farm - Tank 40 ventilation system exhaust in order to assess whether the Short Term Exposure Limit (STEL), or Threshold Limit Value (TLV) levels for mercury will be exceeded during bulk sludge slurry mixing and sludge removal operations. The American Meteorological Society/Environmental Protection Agency Regulatory Model (AERMOD) was used as the main dispersion modelling tool for this analysis. The results indicated that a 45-foot stack is sufficient to raise the plume centerline from the Tank 40 release to prevent mercury exposure problems for any of the stackmore » discharge scenarios provided. However, a 42-foot stack at Tank 40 is sufficient to prevent mercury exposure concerns in all emission scenarios except the 50 mg/m 3 release. At a 42-foot stack height, values exceeding the exposure standards are only measured on receptors located above 34 feet.« less

Hydrogen Embrittlement And Stacking-Fault Energies

NASA Technical Reports Server (NTRS)

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

1988-01-01

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.

Stacking-fault nucleation on Ir(111).

PubMed

Busse, Carsten; Polop, Celia; Müller, Michael; Albe, Karsten; Linke, Udo; Michely, Thomas

2003-08-01

Variable temperature scanning tunneling microscopy experiments reveal that in Ir(111) homoepitaxy islands nucleate and grow both in the regular fcc stacking and in the faulted hcp stacking. Analysis of this effect in dependence on deposition temperature leads to an atomistic model of stacking-fault formation: The large, metastable stacking-fault islands grow by sufficiently fast addition of adatoms to small mobile adatom clusters which occupy in thermal equilibrium the hcp sites with a significant probability. Using parameters derived independently by field ion microscopy, the model accurately describes the results for Ir(111) and is expected to be valid also for other surfaces.

Quality evaluation of six bioactive constituents in goji berry based on capillary electrophoresis field amplified sample stacking.

PubMed

Wang, Wei-Feng; Yang, Jun-Li; Shi, Yan-Ping

2018-04-27

Goji berry, fruits of the plant Lycium barbarum L., has long been used as traditional medicine and functional food in China. In this work, a simple and easy-operation on-line concentration capillary electrophoresis (CE) for detection flavonoids in goji berry was developed by coupling of field amplified sample stacking (FASS) with an electroosmotic (EOF) pump driving water removal process. Due to the EOF pump and electrokinetic injection showing different influence on the concentration, the analytes injection condition should be systemically studied. Thereafter, the verification of the analytes injection conditions was achieved using response surface experimental design. Under the optimum conditions, 86-271 folds sensitivity enhancement upon normal capillary zone electrophoresis (CZE, 50 mbar × 5 s) were achieved for six flavonoids, and the detection limits ranged from 0.35 to 1.82 ng/mL; the LOQ ranged from 1.20 to 6.01 ng/mL. Eventually, the proposed method was applied to detect flavonoids in 30 goji berry samples from different habitats of China; and the results indicated that the flavonoids were rich in the eluent of 30-60% methanol, which provided a reference for extraction of goji berry flavonoids. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Reducing respiratory motion artifacts in positron emission tomography through retrospective stacking

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

Thorndyke, Brian; Schreibmann, Eduard; Koong, Albert

Respiratory motion artifacts in positron emission tomography (PET) imaging can alter lesion intensity profiles, and result in substantially reduced activity and contrast-to-noise ratios (CNRs). We propose a corrective algorithm, coined 'retrospective stacking' (RS), to restore image quality without requiring additional scan time. Retrospective stacking uses b-spline deformable image registration to combine amplitude-binned PET data along the entire respiratory cycle into a single respiratory end point. We applied the method to a phantom model consisting of a small, hot vial oscillating within a warm background, as well as to {sup 18}FDG-PET images of a pancreatic and a liver patient. Comparisons weremore » made using cross-section visualizations, activity profiles, and CNRs within the region of interest. Retrospective stacking was found to properly restore the lesion location and intensity profile in all cases. In addition, RS provided CNR improvements up to three-fold over gated images, and up to five-fold over ungated data. These phantom and patient studies demonstrate that RS can correct for lesion motion and deformation, while substantially improving tumor visibility and background noise.« less

40 CFR 61.44 - Stack sampling.

Code of Federal Regulations, 2013 CFR

2013-07-01

... EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS National Emission Standard for Beryllium Rocket Motor... within 30 days after samples are taken and before any subsequent rocket motor firing or propellant...

40 CFR 61.44 - Stack sampling.

Code of Federal Regulations, 2014 CFR

2014-07-01

... EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS National Emission Standard for Beryllium Rocket Motor... within 30 days after samples are taken and before any subsequent rocket motor firing or propellant...

40 CFR 61.44 - Stack sampling.

Code of Federal Regulations, 2012 CFR

2012-07-01

... EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS National Emission Standard for Beryllium Rocket Motor... within 30 days after samples are taken and before any subsequent rocket motor firing or propellant...

Numerical study on AC loss reduction of stacked HTS tapes by optimal design of flux diverter

NASA Astrophysics Data System (ADS)

Liu, Guole; Zhang, Guomin; Jing, Liwei; Yu, Hui

2017-12-01

High temperature superconducting (HTS) coils are key parts of many AC applications, such as generators, superconducting magnetic energy storage and transformers. AC loss reduction in HTS coils is essential for the commercialization of these HTS devices. Magnetic material is generally used as the flux diverter in an effort to reduce the AC loss in HTS coils. To achieve the greatest reduction in the AC loss of the coils, the flux diverter should be made of a material with low loss and high saturated magnetic density, and the optimization of the geometric size and location of the flux diverter is required. In this paper, we chose Ni-alloy as the flux diverter, which can be processed into a specific shape and size. The influence of the shape and location of the flux diverter on the AC loss characteristics of stacked (RE)BCO tapes is investigated by use of a finite element method. Taking both the AC loss of the (RE)BCO coils and the ferromagnetic loss of the flux diverter into account, the optimal geometry of the flux diverter is obtained. It is found that when the applied current is at half the value of the critical current, the total loss of the HTS stack with the optimal flux diverter is only 18% of the original loss of the HTS stack without the flux diverter. Besides, the effect of the flux diverter on the critical current of the (RE)BCO stack is investigated.

Improved 3D seismic attribute mapping by CRS stacking instead of NMO stacking: Application to a geothermal reservoir in the Polish Basin

NASA Astrophysics Data System (ADS)

Pussak, Marcin; Bauer, Klaus; Stiller, Manfred; Bujakowski, Wieslaw

2014-04-01

Within a seismic reflection processing work flow, the common-reflection-surface (CRS) stack can be applied as an alternative for the conventional normal moveout (NMO) or the dip moveout (DMO) stack. The advantages of the CRS stack include (1) data-driven automatic determination of stacking operator parameters, (2) imaging of arbitrarily curved geological boundaries, and (3) significant increase in signal-to-noise (S/N) ratio by stacking far more traces than used in a conventional stack. In this paper we applied both NMO and CRS stackings to process a sparse 3D seismic data set acquired within a geothermal exploration study in the Polish Basin. The stacked images show clear enhancements in quality achieved by the CRS stack in comparison with the conventional stack. While this was expected from previous studies, we also found remarkable improvements in the quality of seismic attributes when the CRS stack was applied instead of the conventional stack. For the major geothermal target reservoir (Lower Jurassic horizon Ja1), we present a comparison between both stacking methods for a number of common attributes, including root-mean-square (RMS) amplitudes, instantaneous frequencies, coherency, and spectral decomposition attributes derived from the continuous wavelet transform. The attribute maps appear noisy and highly fluctuating after the conventional stack, and are clearly structured after the CRS stack. A seismic facies analysis was finally carried out for the Ja1 horizon using the attributes derived from the CRS stack by using self-organizing map clustering techniques. A corridor parallel to a fault system was identified, which is characterized by decreased RMS amplitudes and decreased instantaneous frequencies. In our interpretation, this region represents a fractured, fluid-bearing compartment within the sandstone reservoir, which indicates favorable conditions for geothermal exploitation.

Role of stacking disorder in ice nucleation

NASA Astrophysics Data System (ADS)

Lupi, Laura; Hudait, Arpa; Peters, Baron; Grünwald, Michael; Gotchy Mullen, Ryan; Nguyen, Andrew H.; Molinero, Valeria

2017-11-01

The freezing of water affects the processes that determine Earth’s climate. Therefore, accurate weather and climate forecasts hinge on good predictions of ice nucleation rates. Such rate predictions are based on extrapolations using classical nucleation theory, which assumes that the structure of nanometre-sized ice crystallites corresponds to that of hexagonal ice, the thermodynamically stable form of bulk ice. However, simulations with various water models find that ice nucleated and grown under atmospheric temperatures is at all sizes stacking-disordered, consisting of random sequences of cubic and hexagonal ice layers. This implies that stacking-disordered ice crystallites either are more stable than hexagonal ice crystallites or form because of non-equilibrium dynamical effects. Both scenarios challenge central tenets of classical nucleation theory. Here we use rare-event sampling and free energy calculations with the mW water model to show that the entropy of mixing cubic and hexagonal layers makes stacking-disordered ice the stable phase for crystallites up to a size of at least 100,000 molecules. We find that stacking-disordered critical crystallites at 230 kelvin are about 14 kilojoules per mole of crystallite more stable than hexagonal crystallites, making their ice nucleation rates more than three orders of magnitude higher than predicted by classical nucleation theory. This effect on nucleation rates is temperature dependent, being the most pronounced at the warmest conditions, and should affect the modelling of cloud formation and ice particle numbers, which are very sensitive to the temperature dependence of ice nucleation rates. We conclude that classical nucleation theory needs to be corrected to include the dependence of the crystallization driving force on the size of the ice crystallite when interpreting and extrapolating ice nucleation rates from experimental laboratory conditions to the temperatures that occur in clouds.

Role of stacking disorder in ice nucleation.

PubMed

Lupi, Laura; Hudait, Arpa; Peters, Baron; Grünwald, Michael; Gotchy Mullen, Ryan; Nguyen, Andrew H; Molinero, Valeria

2017-11-08

The freezing of water affects the processes that determine Earth's climate. Therefore, accurate weather and climate forecasts hinge on good predictions of ice nucleation rates. Such rate predictions are based on extrapolations using classical nucleation theory, which assumes that the structure of nanometre-sized ice crystallites corresponds to that of hexagonal ice, the thermodynamically stable form of bulk ice. However, simulations with various water models find that ice nucleated and grown under atmospheric temperatures is at all sizes stacking-disordered, consisting of random sequences of cubic and hexagonal ice layers. This implies that stacking-disordered ice crystallites either are more stable than hexagonal ice crystallites or form because of non-equilibrium dynamical effects. Both scenarios challenge central tenets of classical nucleation theory. Here we use rare-event sampling and free energy calculations with the mW water model to show that the entropy of mixing cubic and hexagonal layers makes stacking-disordered ice the stable phase for crystallites up to a size of at least 100,000 molecules. We find that stacking-disordered critical crystallites at 230 kelvin are about 14 kilojoules per mole of crystallite more stable than hexagonal crystallites, making their ice nucleation rates more than three orders of magnitude higher than predicted by classical nucleation theory. This effect on nucleation rates is temperature dependent, being the most pronounced at the warmest conditions, and should affect the modelling of cloud formation and ice particle numbers, which are very sensitive to the temperature dependence of ice nucleation rates. We conclude that classical nucleation theory needs to be corrected to include the dependence of the crystallization driving force on the size of the ice crystallite when interpreting and extrapolating ice nucleation rates from experimental laboratory conditions to the temperatures that occur in clouds.

Tunable electro-optic filter stack

DOEpatents

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

2017-09-05

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.

Inflatable containment diaphragm for sealing and removing stacks

DOEpatents

Meskanick, G.R.; Rosso, D.T.

1993-04-13

A diaphragm with an inflatable torus-shaped perimeter is used to seal at least one end of a stack so that debris that might be hazardous will not be released during removal of the stack. A diaphragm is inserted and inflated in the lower portion of a stack just above where the stack is to be cut such that the perimeter of the diaphragm expands and forms a seal against the interior surface of the stack.

Inflatable containment diaphragm for sealing and removing stacks

DOEpatents

Meskanick, Gerald R.; Rosso, David T.

1993-01-01

A diaphragm with an inflatable torus-shaped perimeter is used to seal at least one end of a stack so that debris that might be hazardous will not be released during removal of the stack. A diaphragm is inserted and inflated in the lower portion of a stack just above where the stack is to be cut such that the perimeter of the diaphragm expands and forms a seal against the interior surface of the stack.

Cognitive Protocol Stack Design

DTIC Science & Technology

2015-12-30

SECURITY CLASSIFICATION OF: In the ARO “ Cognitive Protocol Stack Design" project we proposed cognitive networking solutions published in international...areas related to cognitive networking, opening also new lines of research that was not possible to forecast at the beginning of the project. In a...Distribution Unlimited Final Report: Cognitive Protocol Stack Design The views, opinions and/or findings contained in this report are those of the author(s

Hair analysis for abused drugs by capillary zone electrophoresis with field-amplified sample stacking.

PubMed

Tagliaro, F; Manetto, G; Crivellente, F; Scarcella, D; Marigo, M

1998-04-05

The present paper describes the methodological optimisation and validation of a capillary zone electrophoresis method for the determination of morphine, cocaine and 3,4-methylenedioxymethamphetamine (MDMA) in hair, with injection based on field-amplified sample stacking. Diode array UV absorption detection was used to improve analytical selectivity and identification power. Analytical conditions: running buffer 100 mM potassium phosphate adjusted to pH 2.5 with phosphoric acid, applied potential 10 kV, temperature 20 degrees C, injection by electromigration at 10 kV for 10 s, detection by UV absorption at the fixed wavelength of 200 nm or by recording the full spectrum between 190 and 400 nm. Injection conditions: the dried hair extracts were reconstituted with a low-conductivity solvent (0.1 mM formic acid), the injection end of the capillary was dipped in water for 5 s without applying pressure (external rinse step), then a plug of 0.1 mM phosphoric acid was loaded by applying 0.5 psi for 10 s and, finally, the sample was injected electrokinetically at 10 kV for 10 s. Under the described conditions, the limit of detection was 2 ng/ml for MDMA, 8 ng/ml for cocaine and 6 ng/ml for morphine (with a signal-to-noise ratio of 5). The lowest concentration suitable for recording interpretable spectra was about 10-20-times the limit of detection of each analyte. The intraday and day-to-day reproducibility of migration times (n = 6), with internal standardisation, was characterised by R.S.D. values < or = 0.6%; peak area R.S.D.s were better than 10% in intraday and than 15% in day-to-day experiments. Analytical linearity was good with R2 better than 0.9990 for all the analytes.

Nanometer-sized alumina packed microcolumn solid-phase extraction combined with field-amplified sample stacking-capillary electrophoresis for the speciation analysis of inorganic selenium in environmental water samples.

PubMed

Duan, Jiankuan; Hu, Bin; He, Man

2012-10-01

In this paper, a new method of nanometer-sized alumina packed microcolumn SPE combined with field-amplified sample stacking (FASS)-CE-UV detection was developed for the speciation analysis of inorganic selenium in environmental water samples. Self-synthesized nanometer-sized alumina was packed in a microcolumn as the SPE adsorbent to retain Se(IV) and Se(VI) simultaneously at pH 6 and the retained inorganic selenium was eluted by concentrated ammonia. The eluent was used for FASS-CE-UV analysis after NH₃ evaporation. The factors affecting the preconcentration of both Se(IV) and Se(VI) by SPE and FASS were studied and the optimal CE separation conditions for Se(IV) and Se(VI) were obtained. Under the optimal conditions, the LODs of 57 ng L⁻¹ (Se(IV)) and 71 ng L⁻¹ (Se(VI)) were obtained, respectively. The developed method was validated by the analysis of a certified reference material of GBW(E)080395 environmental water and the determined value was in a good agreement with the certified value. It was also successfully applied to the speciation analysis of inorganic selenium in environmental water samples, including Yangtze River water, spring water, and tap water. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Characterization of stacked-crystal PET detector designs for measurement of both TOF and DOI.

PubMed

Schmall, Jeffrey P; Surti, Suleman; Karp, Joel S

2015-05-07

A PET detector with good timing resolution and two-level depth-of-interaction (DOI) discrimination can be constructed using a single-ended readout of scintillator stacks of Lanthanum Bromide (LaBr3), with various Cerium dopant concentrations, including pure Cerium Bromide (CeBr3). The stacked crystal geometry creates a unique signal shape for interactions occurring in each layer, which can be used to identify the DOI, while retaining the inherently good timing properties of LaBr3 and CeBr3. In this work, single pixel elements are used to optimize the choice of scintillator, coupling of layers, and type of photodetector, evaluating the performance using a fast, single-channel photomultiplier tube (PMT) and a single 4 × 4 mm(2) silicon photomultiplier (SiPM). We also introduce a method to quantify and evaluate the DOI discrimination accuracy. From signal shape measurements using fast waveform sampling, we found that in addition to differences in signal rise times, between crystal layers, there were also differences in the signal fall times. A DOI accuracy of 98% was achieved using our classification method for a stacked crystal pair, consisting of a 15 mm long LaBr3(Ce:20%) crystal on top of a 15 mm long CeBr3 crystal, readout using a PMT. A DOI accuracy of 95% was measured with a stack of two, identical, 12 mm long, CeBr3 crystals. The DOI accuracy of this crystal pair was reduced to 91% when using a SiPM for readout. For the stack of two, 12 mm long, CeBr3 crystals, a coincidence timing resolution (average of timing results from the top and bottom layer) of 199 ps was measured using a PMT, and this was improved to 153 ps when using a SiPM. These results show that with stacked LaBr3/CeBr3 scintillators and fast waveform sampling nearly perfect DOI accuracy can be achieved with excellent timing resolution-timing resolution that is only minimally degraded compared to results from a single CeBr3 crystal of comparable length to the stacked crystals. The

Characterization of stacked-crystal PET detector designs for measurement of both TOF and DOI

PubMed Central

Schmall, Jeffrey P; Surti, Suleman; Karp, Joel S

2015-01-01

A PET detector with good timing resolution and two-level depth-of-interaction (DOI) discrimination can be constructed using a single-ended readout of scintillator stacks of Lanthanum Bromide (LaBr3), with various Cerium dopant concentrations, including pure Cerium Bromide (CeBr3). The stacked crystal geometry creates a unique signal shape for interactions occurring in each layer, which can be used to identify the DOI, while retaining the inherently good timing properties of LaBr3 and CeBr3. In this work, single pixel elements are used to optimize the choice of scintillator, coupling of layers, and type of photodetector, evaluating the performance using a fast, single-channel photomultiplier tube (PMT) and a single 4×4 mm2 silicon photomultiplier (SiPM). We also introduce a method to quantify and evaluate the DOI discrimination accuracy. From signal shape measurements using fast waveform sampling, we found that in addition to differences in signal rise times, between crystal layers, there were also differences in the signal fall times. A DOI accuracy of 98% was achieved using our classification method for a stacked crystal pair, consisting of a 15-mm long LaBr3(Ce:20%) crystal on top of a 15-mm long CeBr3 crystal, readout using a PMT. A DOI accuracy of 95% was measured with a stack of two, identical, 12-mm long, CeBr3 crystals. The DOI accuracy of this crystal pair was reduced to 91% when using a SiPM for readout. For the stack of two, 12-mm long, CeBr3 crystals, a coincidence timing resolution (average of timing results from the top and bottom layer) of 199 ps was measured using a PMT, and this was improved to 153 ps when using a SiPM. These results show that with stacked LaBr3/CeBr3 scintillators and fast waveform sampling nearly perfect DOI accuracy can be achieved with excellent timing resolution—timing resolution that is only minimally degraded compared to results from a single CeBr3 crystal of comparable length to the stacked crystals. The interface in the

A Decentralized IT Architecture for Locating and Negotiating Access to Biobank Samples.

PubMed

Proynova, Rumyana; Alexandre, Diogo; Lablans, Martin; Van Enckevort, David; Mate, Sebastian; Eklund, Niina; Silander, Kaisa; Hummel, Michael; Holub, Petr; Ückert, Frank

2017-01-01

There is a need among researchers for the easy discoverability of biobank samples. Currently, there is no uniform way for finding samples and negotiate access. Instead, researchers have to communicate with each biobank separately. We present the architecture for the BBMRI-CS IT platform, whose goal is to facilitate sample location and access. We chose a decentral approach, which allows for strong data protection and provides the high flexibility needed in the highly heterogeneous landscape of European biobanks. This is the first implementation of a decentral search in the biobank field. With the addition of a Negotiator component, it also allows for easy communication and a follow-through of the lengthy approval process for accessing samples.

Breath stacking in children with neuromuscular disorders.

PubMed

Jenkins, H M; Stocki, A; Kriellaars, D; Pasterkamp, H

2014-06-01

Respiratory muscle weakness in neuromuscular disorders (NMD) can lead to shallow breathing and respiratory insufficiency over time. Children with NMD often cannot perform maneuvers to recruit lung volume. In adults, breath stacking with a mask and one-way valve can achieve significantly increased lung volumes. To evaluate involuntary breath stacking (IBS) in NMD, we studied 23 children of whom 15 were cognitively aware and able to communicate verbally. For IBS, a one-way valve and pneumotachograph were attached to a face mask. Tidal volumes (Vt) and minute ventilation (VE ) were calculated from airflow over 30 sec before and after 15 sec of expiratory valve closure. Six cooperative male subjects with Duchenne muscular dystrophy (DMD) participated in a subsequent comparison of IBS with voluntary breath stacking (VBS) and supported breath stacking (SBS). The average Vt in those studied with IBS was 277 ml (range 29-598 ml). The average increase in volume by stacking was 599 ml (range -140 to 2,916 ml) above Vt . The average number of stacked breaths was 4.5 (range 0-17). VE increased on average by 18% after stacking (P < 0.05, paired t-test). Oxygen saturation did not change after stacking. Four of the 23 children did not breath stack. Compared to IBS, VBS achieved similar volumes in the six subjects with DMD but SBS was more successful in those with greatest muscle weakness. IBS may achieve breath volumes of approximately three times Vt and may be particularly useful in non-cooperative subjects with milder degrees of respiratory muscle weakness. © 2013 Wiley Periodicals, Inc.

Principles for Instructional Stack Development in HyperCard.

ERIC Educational Resources Information Center

McEneaney, John E.

The purpose of this paper is to provide information about obtaining and using HyperCard stacks that introduce users to principles of stack development. The HyperCard stacks described are available for downloading free of charge from a server at Indiana University South Bend. Specific directions are given for stack use, with advice for beginners. A…

A new approach for biological online testing of stack gas condensate from municipal waste incinerators.

PubMed

Elsner, Dorothea; Fomin, Anette

2002-01-01

A biological testing system for the monitoring of stack gas condensates of municipal waste incinerators has been developed using Euglena gracilis as a test organism. The motility, velocity and cellular form of the organisms were the endpoints, calculated by an image analysis system. All endpoints showed statistically significant changes in a short time when organisms were exposed to samples collected during combustion situations with increased pollutant concentrations. The velocity of the organisms proved to be the most appropriate endpoint. A semi-continuous system with E. gracilis for monitoring stack gas condensate is proposed, which could result in an online system for testing stack gas condensates in the future.

GINSU: Guaranteed Internet Stack Utilization

DTIC Science & Technology

2005-11-01

Computer Architecture Data Links, Internet , Protocol Stacks 16. PRICE CODE 17. SECURITY CLASSIFICATION OF REPORT UNCLASSIFIED 18. SECURITY...AFRL-IF-RS-TR-2005-383 Final Technical Report November 2005 GINSU: GUARANTEED INTERNET STACK UTILIZATION Trusted... Information Systems, Inc. Sponsored by Defense Advanced Research Projects Agency DARPA Order No. ARPS APPROVED FOR PUBLIC

Optimization of throughput in semipreparative chiral liquid chromatography using stacked injection.

PubMed

Taheri, Mohammadreza; Fotovati, Mohsen; Hosseini, Seyed-Kiumars; Ghassempour, Alireza

2017-10-01

An interesting mode of chromatography for preparation of pure enantiomers from pure samples is the method of stacked injection as a pseudocontinuous procedure. Maximum throughput and minimal production costs can be achieved by the use of total chiral column length in this mode of chromatography. To maximize sample loading, often touching bands of the two enantiomers is automatically achieved. Conventional equations show direct correlation between touching-band loadability and the selectivity factor of two enantiomers. The important question for one who wants to obtain the highest throughput is "How to optimize different factors including selectivity, resolution, run time, and loading of the sample in order to save time without missing the touching-band resolution?" To answer this question, tramadol and propranolol were separated on cellulose 3,5-dimethyl phenyl carbamate, as two pure racemic mixtures with low and high solubilities in mobile phase, respectively. The mobile phase composition consisted of n-hexane solvent with alcohol modifier and diethylamine as the additive. A response surface methodology based on central composite design was used to optimize separation factors against the main responses. According to the stacked injection properties, two processes were investigated for maximizing throughput: one with a poorly soluble and another with a highly soluble racemic mixture. For each case, different optimization possibilities were inspected. It was revealed that resolution is a crucial response for separations of this kind. Peak area and run time are two critical parameters in optimization of stacked injection for binary mixtures which have low solubility in the mobile phase. © 2017 Wiley Periodicals, Inc.

Assessing Elementary Algebra with STACK

ERIC Educational Resources Information Center

Sangwin, Christopher J.

2007-01-01

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, http://www.stack.bham.ac.uk/, which uses the CAS…

40 CFR 51.118 - Stack height provisions.

Code of Federal Regulations, 2014 CFR

2014-07-01

... exceeds good engineering practice or by any other dispersion technique, except as provided in § 51.118(b... based on a good engineering practice stack height that exceeds the height allowed by § 51.100(ii) (1) or... actual stack height of any source. (b) The provisions of § 51.118(a) shall not apply to (1) stack heights...

Mobility of rare earth elements, yttrium and scandium from a phosphogypsum stack: Environmental and economic implications.

PubMed

Cánovas, Carlos Ruiz; Macías, Francisco; Pérez López, Rafael; Nieto, José Miguel

2018-03-15

This paper investigates the mobility and fluxes of REE, Y and Sc under weathering conditions from an anomalously metal-rich phosphogypsum stack in SW Spain. The interactions of the phosphogypsum stack with rainfall and organic matter-rich solutions, simulating the weathering processes observed due to its location on salt-marshes, were simulated by leaching tests (e.g. EN 12457-2 and TCLP). Despite the high concentration of REE, Y and Sc contained in the phosphogypsum stack, their mobility during the leaching tests was very low; <0.66% and 1.8% of the total content of these elements were released during both tests. Chemical and mineralogical evidences suggest that phosphate minerals may act as sources of REE and Y in the phosphogypsum stack while fluoride minerals may act as sinks, controlling their mobility. REE fractionation processes were identified in the phosphogypsum stack; a depletion of LREE in the saturated zone was identified due probably to the dissolution of secondary LREE phosphates previously formed during apatite dissolution in the industrial process. Thus, the vadose zone of the stack would preserve the original REE signature of phosphate rocks. On the other hand, an enrichment of MREE in relation to HREE of edge outflows is observed due to the higher influence of estuarine waters on the leaching process of the phosphogypsum stack. Despite the low mobility of REE, Y and Sc in the phosphogypsum, around 104kg/yr of REE and 40kg/yr of Y and Sc are released from the stack to the estuary, which may imply an environmental concern. The information obtained in this study could be used to optimize extraction methods aimed to recover REE, Y and Sc from phosphogypsum, mitigating the pollution to the environment. Copyright © 2017 Elsevier B.V. All rights reserved.

Technical report on the surface reconstruction of stacked contours by using the commercial software

NASA Astrophysics Data System (ADS)

Shin, Dong Sun; Chung, Min Suk; Hwang, Sung Bae; Park, Jin Seo

2007-03-01

After drawing and stacking contours of a structure, which is identified in the serially sectioned images, three-dimensional (3D) image can be made by surface reconstruction. Usually, software is composed for the surface reconstruction. In order to compose the software, medical doctors have to acquire the help of computer engineers. So in this research, surface reconstruction of stacked contours was tried by using commercial software. The purpose of this research is to enable medical doctors to perform surface reconstruction to make 3D images by themselves. The materials of this research were 996 anatomic images (1 mm intervals) of left lower limb, which were made by serial sectioning of a cadaver. On the Adobe Photoshop, contours of 114 anatomic structures were drawn, which were exported to Adobe Illustrator files. On the Maya, contours of each anatomic structure were stacked. On the Rhino, superoinferior lines were drawn along all stacked contours to fill quadrangular surfaces between contours. On the Maya, the contours were deleted. 3D images of 114 anatomic structures were assembled with their original locations preserved. With the surface reconstruction technique, developed in this research, medical doctors themselves could make 3D images of the serially sectioned images such as CTs and MRIs.

A Critical Assessment of Bias in Survey Studies Using Location-Based Sampling to Recruit Patrons in Bars

PubMed Central

Morrison, Christopher; Lee, Juliet P.; Gruenewald, Paul J.; Marzell, Miesha

2015-01-01

Location-based sampling is a method to obtain samples of people within ecological contexts relevant to specific public health outcomes. Random selection increases generalizability, however in some circumstances (such as surveying bar patrons) recruitment conditions increase risks of sample bias. We attempted to recruit representative samples of bars and patrons in six California cities, but low response rates precluded meaningful analysis. A systematic review of 24 similar studies revealed that none addressed the key shortcomings of our study. We recommend steps to improve studies that use location-based sampling: (i) purposively sample places of interest, (ii) utilize recruitment strategies appropriate to the environment, and (iii) provide full information on response rates at all levels of sampling. PMID:26574657

Planning studies for measurement of chemical emissions in stack gases of coal-fired power plants. Final report

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

Barrett, W.J.; Gooch, J.P.; Dahlin, R.S.

1983-03-01

Airborne emissions from coal-fired power plants consist of sulfur, nitrogen, and carbon oxides, as well as traces of certain metals or elements, radionuclides, and organic compounds that have the potential of producing adverse health effects if inhaled. To assess this potential toxicity, samples must be obtained and characterized on the basis of quantity, their chemistry, and toxicity. Sample representativeness and use of proper chemical-biological procedures are the critical for providing input into current research directed toward source apportionment and inhalation toxicology. Obtaining a valid stack sample (gases and particles) from each of more than 1500 US coal-fired power plant ismore » not practical; consequently 33 plants have been selected, taking into account plant design and operating parameters that can affect the characteristics of stack chemical emissions. Since such a program has an estimated cost of $20 million over many years, it is recommended that the initial program consists of sampling only six of the 33 units, selected with EPRI guidance, at an estimated cost of $3.5 million over a 30 month period. The plan is directed at in-stack sampling, plume and atmospheric transformations being beyond the project scope. Various stack sampling methods are considered. For particles, a modified SASS train seems best, and for gases, either resin traps or impingers are probably best. Artifact formation must be minimized. Chemical analysis procedures are to be guided by the known toxicity of species present. Procedures are outlined for organics (volatile and nonvolatile), trace elements, inorganics, and gases. Bioassay methods are restricted to in vitro, subdivided into those assays that detect genetic and direct cellular toxicity.« less

HPC Software Stack Testing Framework

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

Garvey, Cormac

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).

Dynamical stability of slip-stacking particles

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

Eldred, Jeffrey; Zwaska, Robert

2014-09-01

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.

Prolonged incubation and stacked film exposure improve sensitivity in western blotting.

PubMed

Luo, Haitao; Rankin, Gary O; Straley, Shannon; Chen, Yi Charlie

2011-01-01

Western blotting is a basic technique for protein detection. For proteins of less abundance or antibodies of poorer quality, an increased sensitivity is often desired. Although it is commonly known that higher concentrations of antibodies and prolonged film exposure times will help improve sensitivity in western blots, both measures come with their own risks, and it is often unclear to which extent these measures should be applied. We conducted time-course studies to investigate protein-antibody interactions and primary antibody-secondary antibody interactions in western blotting. We also propose a protocol of stacked film exposure and have tested it in standard curves and cancer cell samples. Our study found that protein-primary antibody interactions and primary antibody-secondary antibody interactions could take a longer time than commonly used "one hour" or "overnight", and in some cases longer than 48h, to reach its maximum binding. We also show that the modified protocol of stacked film exposure works well for both standard curves and biological samples, reaching a maximum sensitivity in western blots without blurring target signals or increasing backgrounds. In addition to regular optimization of antibody concentrations and film exposure time, a prolonged incubation with antibodies and stacked film exposure will also help improve sensitivity and reduce background in western blotting. Copyright © 2011 Elsevier Inc. All rights reserved.

40 CFR 75.72 - Determination of NOX mass emissions for common stack and multiple stack configurations.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 16 2011-07-01 2011-07-01 false Determination of NOX mass emissions... ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) CONTINUOUS EMISSION MONITORING NOX Mass Emissions Provisions § 75.72 Determination of NOX mass emissions for common stack and multiple stack...

π-π stacking tackled with density functional theory

PubMed Central

Swart, Marcel; van der Wijst, Tushar; Fonseca Guerra, Célia

2007-01-01

Through comparison with ab initio reference data, we have evaluated the performance of various density functionals for describing π-π interactions as a function of the geometry between two stacked benzenes or benzene analogs, between two stacked DNA bases, and between two stacked Watson–Crick pairs. Our main purpose is to find a robust and computationally efficient density functional to be used specifically and only for describing π-π stacking interactions in DNA and other biological molecules in the framework of our recently developed QM/QM approach "QUILD". In line with previous studies, most standard density functionals recover, at best, only part of the favorable stacking interactions. An exception is the new KT1 functional, which correctly yields bound π-stacked structures. Surprisingly, a similarly good performance is achieved with the computationally very robust and efficient local density approximation (LDA). Furthermore, we show that classical electrostatic interactions determine the shape and depth of the π-π stacking potential energy surface. Figure Additivity approximation for the π-π interaction between two stacked Watson–Crick base pairs in terms of pairwise interactions between individual bases Electronic supplementary material The online version of this article (doi:10.1007/s00894-007-0239-y) contains supplementary material, which is available to authorized users. PMID:17874150

Stacking interactions in PUF-RNA complexes

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

Yiling Koh, Yvonne; Wang, Yeming; Qiu, Chen

2012-07-02

Stacking interactions between amino acids and bases are common in RNA-protein interactions. Many proteins that regulate mRNAs interact with single-stranded RNA elements in the 3' UTR (3'-untranslated region) of their targets. PUF proteins are exemplary. Here we focus on complexes formed between a Caenorhabditis elegans PUF protein, FBF, and its cognate RNAs. Stacking interactions are particularly prominent and involve every RNA base in the recognition element. To assess the contribution of stacking interactions to formation of the RNA-protein complex, we combine in vivo selection experiments with site-directed mutagenesis, biochemistry, and structural analysis. Our results reveal that the identities of stackingmore » amino acids in FBF affect both the affinity and specificity of the RNA-protein interaction. Substitutions in amino acid side chains can restrict or broaden RNA specificity. We conclude that the identities of stacking residues are important in achieving the natural specificities of PUF proteins. Similarly, in PUF proteins engineered to bind new RNA sequences, the identity of stacking residues may contribute to 'target' versus 'off-target' interactions, and thus be an important consideration in the design of proteins with new specificities.« less

Determination of herbicides in mineral and stagnant waters at ng/L levels using capillary electrophoresis and UV detection combined with solid-phase extraction and sample stacking.

PubMed

Hernández-Borges, Javier; García-Montelongo, Francisco J; Cifuentes, Alejandro; Rodríguez-Delgado, Miguel Angel

2005-04-08

In this work, the combined use of solid-phase extraction (SPE) and on-line preconcentration strategies as normal stacking mode (NSM) and stacking with matrix removal (SWMR) for the ultrasensitive and simultaneous capillary electrophoresis-ultraviolet analysis (CE-UV) of five triazolopyrimidine sulfonanilide pesticides (i.e., diclosulam, cloransulam-methyl, flumetsulam, metosulam and florasulam) in different types of water is investigated. An adequate separation electrolyte for the separation and stacking of these pesticides was obtained, considering also its compatibility with MS detection, which consisted of 24 mM formic acid and 16 mM ammonium carbonate at pH 6.4. It was observed that the use of this running buffer together with the SWMR preconcentration method provided the best results in terms of sensitivity (between 6.54 and 11.9 microg/L) and peak efficiency (up to 550000 theoretical plates per meter, NTP/m). When this on-line preconcentration procedure was combined with an off-line sample preconcentration step as SPE using C18 cartridges, the selected herbicides could be detected in the ng/L range. The optimized SPE-SWMR-CE-UV method was applied to the determination of the selected group of pesticides in spiked and non-spiked mineral and stagnant waters. Recoveries ranged between 55 and 110% and limits of detection between 131 and 342 ng/L. This work shows the great possibilities of the combined use of SPE-SWMR-CE-UV to overcome the sensitivity problems usually linked to CE analysis.

Type A verification report for the high flux beam reactor stack and grounds, Brookhaven National Laboratory, Upton, New York

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

Harpenau, Evan M.

The U.S. Department of Energy (DOE) Order 458.1 requires independent verification (IV) of DOE cleanup projects (DOE 2011). The Oak Ridge Institute for Science and Education (ORISE) has been designated as the responsible organization for IV of the High Flux Beam Reactor (HFBR) Stack and Grounds area at Brookhaven National Laboratory (BNL) in Upton, New York. The IV evaluation may consist of an in-process inspection with document and data reviews (Type A Verification) or a confirmatory survey of the site (Type B Verification). DOE and ORISE determined that a Type A verification of the documents and data for the HFBRmore » Stack and Grounds: Survey Units (SU) 6, 7, and 8 was appropriate based on the initial survey unit classification, the walkover surveys, and the final analytical results provided by the Brookhaven Science Associates (BSA). The HFBR Stack and Grounds surveys began in June 2011 and were completed in September 2011. Survey activities by BSA included gamma walkover scans and sampling of the as-left soils in accordance with the BSA Work Procedure (BNL 2010a). The Field Sampling Plan - Stack and Remaining HFBR Outside Areas (FSP) stated that gamma walk-over surveys would be conducted with a bare sodium iodide (NaI) detector, and a collimated detector would be used to check areas with elevated count rates to locate the source of the high readings (BNL 2010b). BSA used the Mult- Agency Radiation Survey and Site Investigation Manual (MARSSIM) principles for determining the classifications of each survey unit. Therefore, SUs 6 and 7 were identified as Class 1 and SU 8 was deemed Class 2 (BNL 2010b). Gamma walkover surveys of SUs 6, 7, and 8 were completed using a 2X2 NaI detector coupled to a data-logger with a global positioning system (GPS). The 100% scan surveys conducted prior to the final status survey (FSS) sampling identified two general soil areas and two isolated soil locations with elevated radioactivity. The general areas of elevated activity

Application of Phase-Weighted Stacking to Low-Frequency Earthquakes near the Alpine Fault, Central Southern Alps, New Zealand

NASA Astrophysics Data System (ADS)

Baratin, L. M.; Townend, J.; Chamberlain, C. J.; Savage, M. K.

2015-12-01

Characterising seismicity in the vicinity of the Alpine Fault, a major transform boundary late in its typical earthquake cycle, may provide constraints on the state of stress preceding a large earthquake. Here, we use recently detected tremor and low-frequency earthquakes (LFEs) to examine how slow tectonic deformation is loading the Alpine Fault toward an anticipated major rupture. We work with a continuous seismic dataset collected between 2009 and 2012 from a network of short-period seismometers, the Southern Alps Microearthquake Borehole Array (SAMBA). Fourteen primary LFE templates have been used to scan the dataset using a matched-filter technique based on an iterative cross-correlation routine. This method allows the detection of similar signals and establishes LFE families with common hypocenter locations. The detections are then combined for each LFE family using phase-weighted stacking (Thurber et al., 2014) to produce a signal with the highest possible signal to noise ratio. We find this method to be successful in increasing the number of LFE detections by roughly 10% in comparison with linear stacking. Our next step is to manually pick polarities on first arrivals of the phase-weighted stacked signals and compute preliminary locations. We are working to estimate LFE focal mechanism parameters and refine the focal mechanism solutions using an amplitude ratio technique applied to the linear stacks. LFE focal mechanisms should provide new insight into the geometry and rheology of the Alpine Fault and the stress field prevailing in the central Southern Alps.

Numerical simulation of a mini PEMFC stack

NASA Astrophysics Data System (ADS)

Liu, Zhixiang; Mao, Zongqiang; Wang, Cheng; Zhuge, Weilin; Zhang, Yangjun

Fuel cell modeling and simulation has aroused much attention recently because it can probe transport and reaction mechanism. In this paper, a computational fuel cell dynamics (CFCD) method was applied to simulate a proton exchange membrane fuel cell (PEMFC) stack for the first time. The air cooling mini fuel cell stack consisted of six cells, in which the active area was 8 cm 2 (2 cm × 4 cm). With reasonable simplification, the computational elements were effectively reduced and allowed a simulation which could be conducted on a personal computer without large-scale parallel computation. The results indicated that the temperature gradient inside the fuel cell stack was determined by the flow rate of the cooling air. If the air flow rate is too low, the stack could not be effectively cooled and the temperature will rise to a range that might cause unstable stack operation.

Full Piezoelectric Multilayer-Stacked Hybrid Actuation/Transduction Systems

NASA Technical Reports Server (NTRS)

Su, Ji; Jiang, Xiaoning; Zu, Tian-Bing

2011-01-01

The Stacked HYBATS (Hybrid Actuation/Transduction system) demonstrates significantly enhanced electromechanical performance by using the cooperative contributions of the electromechanical responses of multilayer, stacked negative strain components and positive strain components. Both experimental and theoretical studies indicate that, for Stacked HYBATS, the displacement is over three times that of a same-sized conventional flextensional actuator/transducer. The coupled resonance mode between positive strain and negative strain components of Stacked HYBATS is much stronger than the resonance of a single element actuation only when the effective lengths of the two kinds of elements match each other. Compared with the previously invented hybrid actuation system (HYBAS), the multilayer Stacked HYBATS can be designed to provide high mechanical load capability, low voltage driving, and a highly effective piezoelectric constant. The negative strain component will contract, and the positive strain component will expand in the length directions when an electric field is applied on the device. The interaction between the two elements makes an enhanced motion along the Z direction for Stacked-HYBATS. In order to dominate the dynamic length of Stacked-HYBATS by the negative strain component, the area of the cross-section for the negative strain component will be much larger than the total cross-section areas of the two positive strain components. The transverse strain is negative and longitudinal strain positive in inorganic materials, such as ceramics/single crystals. Different piezoelectric multilayer stack configurations can make a piezoelectric ceramic/single-crystal multilayer stack exhibit negative strain or positive strain at a certain direction without increasing the applied voltage. The difference of this innovation from the HYBAS is that all the elements can be made from one-of-a-kind materials. Stacked HYBATS can provide an extremely effective piezoelectric

A minimum distance estimation approach to the two-sample location-scale problem.

PubMed

Zhang, Zhiyi; Yu, Qiqing

2002-09-01

As reported by Kalbfleisch and Prentice (1980), the generalized Wilcoxon test fails to detect a difference between the lifetime distributions of the male and female mice died from Thymic Leukemia. This failure is a result of the test's inability to detect a distributional difference when a location shift and a scale change exist simultaneously. In this article, we propose an estimator based on the minimization of an average distance between two independent quantile processes under a location-scale model. Large sample inference on the proposed estimator, with possible right-censorship, is discussed. The mouse leukemia data are used as an example for illustration purpose.

Open stack thermal battery tests

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

Long, Kevin N.; Roberts, Christine C.; Grillet, Anne M.

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 transversemore » 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.« less

PEM fuel cell stack heat and mass management

NASA Technical Reports Server (NTRS)

Vanderborgh, Nicholas E.; Kimble, Michael C.; Huff, James R.; Hedstrom, James C.

1992-01-01

PEM stacks are under evaluation as candidates for future space power technology. Results of long-term operation on a set of contemporary stacks fitted with different proton exchange membrane materials are given. Data on water balances show effects of membrane materials on stack performance.

Proposed Cavity for Reduced Slip-Stacking Loss

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

Eldred, J.; Zwaska, R.

This paper employs a novel dynamical mechanism to improve the performance of slip-stacking. Slip-stacking in an accumulation technique used at Fermilab since 2004 which nearly double the proton intensity. During slip-stacking, the Recycler or the Main Injector stores two particles beams that spatially overlap but have different momenta. The two particle beams are longitudinally focused 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. In simulation, we findmore » the proposed RF cavity significantly enhances the stable bucket area and reduces slip-stacking losses under reasonable injection scenarios. We quantify and map the stability of the parameter space for any accelerator implementing slip-stacking with the addition of a harmonic RF cavity.« less

Laser pulse stacking method

DOEpatents

Moses, Edward I.

1992-01-01

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.

Laser pulse stacking method

DOEpatents

Moses, E.I.

1992-12-01

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.

Manifold seal for fuel cell stack assembly

DOEpatents

Schmitten, Phillip F.; Wright, Maynard K.

1989-01-01

An assembly for sealing a manifold to a stack of fuel cells includes a first resilient member for providing a first sealing barrier between the manifold and the stack. A second resilient member provides a second sealing barrier between the manifold and the stack. The first and second resilient members are retained in such a manner as to define an area therebetween adapted for retaining a sealing composition.

Converting factors for stacked wood

Treesearch

C. A. Bickford

1957-01-01

Though the "cord" is used as a standard unit of measure for stacked wood, there is much confusion as to what a cord is and how it can be properly converted to other units of measure. The amount of solid wood in a pile varies greatly depending on the size, straightness, and evenness of the material in the pile, and also on the closeness of stacking.

3D P and S Wave Velocity Structure and Tremor Locations in the Parkfield Region

NASA Astrophysics Data System (ADS)

Zeng, X.; Thurber, C. H.; Shelly, D. R.; Bennington, N. L.; Cochran, E. S.; Harrington, R. M.

2014-12-01

We have assembled a new dataset to refine the 3D seismic velocity model in the Parkfield region. The S arrivals from 184 earthquakes recorded by the Parkfield Experiment to Record MIcroseismicity and Tremor array (PERMIT) during 2010-2011 were picked by a new S wave picker, which is based on machine learning. 74 blasts have been assigned to four quarries, whose locations were identified with Google Earth. About 1000 P and S wave arrivals from these blasts at permanent seismic network were also incorporated. Low frequency earthquakes (LFEs) occurring within non-volcanic tremor (NVT) are valuable for improving the precision of NVT location and the seismic velocity model at greater depths. Based on previous work (Shelley and Hardebeck, 2010), waveforms of hundreds of LFEs in same family were stacked to improve signal qualify. In a previous study (McClement et al., 2013), stacked traces of more than 30 LFE families at the Parkfileld Array Seismic Observatory (PASO) have been picked. We expanded our work to include LFEs recorded by the PERMIT array. The time-frequency Phase Weight Stacking (tf-PWS) method was introduced to improve the stack quality, as direct stacking does not produce clear S-wave arrivals on the PERMIT stations. This technique uses the coherence of the instantaneous phase among the stacked signals to enhance the signal-to-noise ratio (SNR) of the stack. We found that it is extremely effective for picking LFE arrivals (Thurber et al., 2014). More than 500 P and about 1000 S arrivals from 58 LFE families were picked at the PERMIT and PASO arrays. Since the depths of LFEs are much deeper than earthquakes, we are able to extend model resolution to lower crustal depths. Both P and S wave velocity structure have been obtained with the tomoDD method. The result suggests that there is a low velocity zone (LVZ) in the lower crust and the location of the LVZ is consistent with the high conductivity zone beneath the southern segment of the Rinconada fault that

Highly sensitive chiral analysis in capillary electrophoresis with large-volume sample stacking with an electroosmotic flow pump.

PubMed

Kawai, Takayuki; Koino, Hiroshi; Sueyoshi, Kenji; Kitagawa, Fumihiko; Otsuka, Koji

2012-07-13

To improve the sensitivity in chiral analysis by capillary electrophoresis without loss of optical resolution, application of large-volume sample stacking with an electroosmotic flow pump (LVSEP) was investigated. Effects of the addition of cyclodextrin (CD) into a running solution on the LVSEP preconcentration was theoretically studied, where the preconcentration efficiency and effective separation length would be slightly increased if the effective electrophoretic velocity (v(ep,eff,BGS)) of the analytes was decreased by interacting with CD. In LVSEP-CD-modified capillary zone electrophoresis (CDCZE) and LVSEP-CD electrokinetic chromatography with reduced v(ep,eff,BGS), up to 1000-fold sensitivity increases were achieved with almost no loss of resolution. In LVSEP-CD-modified micellar electrokinetic chromatography of amino acids with increased v(ep,eff,BGS), a 1300-fold sensitivity increase was achieved without much loss of resolution, indicating the versatile applicability of LVSEP to many separation modes. An enantio-excess (EE) assay was also carried out in LVSEP-CDCZE, resulting in successful analyses of up to 99.6% EE. Finally, we analyzed ibuprofen in urine by desalting with a C₁₈ solid-phase extraction column. As a typical result, 250ppb ibuprofen was well concentrated and optically resolved with 84.0-86.6% recovery in LVSEP-CDCZE, indicating the applicability of LVSEP to real samples containing a large amount of unnecessary background salts. Copyright © 2012 Elsevier B.V. All rights reserved.

Horizontal high speed stacking for batteries with prismatic cans

DOEpatents

Bartos, Andrew L.; Lin, Yhu-Tin; Turner, III, Raymond D.

2016-06-14

A system and method for stacking battery cells or related assembled components. Generally planar, rectangular (prismatic-shaped) battery cells are moved from an as-received generally vertical stacking orientation to a generally horizontal stacking orientation without the need for robotic pick-and-place equipment. The system includes numerous conveyor belts that work in cooperation with one another to deliver, rotate and stack the cells or their affiliated assemblies. The belts are outfitted with components to facilitate the cell transport and rotation. The coordinated movement between the belts and the components promote the orderly transport and rotation of the cells from a substantially vertical stacking orientation into a substantially horizontal stacking orientation. The approach of the present invention helps keep the stacked assemblies stable so that subsequent assembly steps--such as compressing the cells or attaching electrical leads or thermal management components--may proceed with a reduced chance of error.

40 CFR 52.2633 - Stack height regulations.

Code of Federal Regulations, 2011 CFR

2011-07-01

... (CONTINUED) APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS (CONTINUED) Wyoming § 52.2633 Stack height... with the “Guideline for Determination of Good Engineering Practice Stack Height (Technical Support...

Membrane adhesion dictates Golgi stacking and cisternal morphology.

PubMed

Lee, Intaek; Tiwari, Neeraj; Dunlop, Myun Hwa; Graham, Morven; Liu, Xinran; Rothman, James E

2014-02-04

Two classes of proteins that bind to each other and to Golgi membranes have been implicated in the adhesion of Golgi cisternae to each other to form their characteristic stacks: Golgi reassembly and stacking proteins 55 and 65 (GRASP55 and GRASP65) and Golgin of 45 kDa and Golgi matrix protein of 130 kDa. We report here that efficient stacking occurs in the absence of GRASP65/55 when either Golgin is overexpressed, as judged by quantitative electron microscopy. The Golgi stacks in these GRASP-deficient HeLa cells were normal both in morphology and in anterograde cargo transport. This suggests the simple hypothesis that the total amount of adhesive energy gluing cisternae dictates Golgi cisternal stacking, irrespective of which molecules mediate the adhesive process. In support of this hypothesis, we show that adding artificial adhesive energy between cisternae and mitochondria by dimerizing rapamycin-binding domain and FK506-binding protein domains that are attached to cisternal adhesive proteins allows mitochondria to invade the stack and even replace Golgi cisternae within a few hours. These results indicate that although Golgi stacking is a highly complicated process involving a large number of adhesive and regulatory proteins, the overriding principle of a Golgi stack assembly is likely to be quite simple. From this simplified perspective, we propose a model, based on cisternal adhesion and cisternal maturation as the two core principles, illustrating how the most ancient form of Golgi stacking might have occurred using only weak cisternal adhesive processes because of the differential between the rate of influx and outflux of membrane transport through the Golgi.

Membrane adhesion dictates Golgi stacking and cisternal morphology

PubMed Central

Lee, Intaek; Tiwari, Neeraj; Dunlop, Myun Hwa; Graham, Morven; Liu, Xinran; Rothman, James E.

2014-01-01

Two classes of proteins that bind to each other and to Golgi membranes have been implicated in the adhesion of Golgi cisternae to each other to form their characteristic stacks: Golgi reassembly and stacking proteins 55 and 65 (GRASP55 and GRASP65) and Golgin of 45 kDa and Golgi matrix protein of 130 kDa. We report here that efficient stacking occurs in the absence of GRASP65/55 when either Golgin is overexpressed, as judged by quantitative electron microscopy. The Golgi stacks in these GRASP-deficient HeLa cells were normal both in morphology and in anterograde cargo transport. This suggests the simple hypothesis that the total amount of adhesive energy gluing cisternae dictates Golgi cisternal stacking, irrespective of which molecules mediate the adhesive process. In support of this hypothesis, we show that adding artificial adhesive energy between cisternae and mitochondria by dimerizing rapamycin-binding domain and FK506-binding protein domains that are attached to cisternal adhesive proteins allows mitochondria to invade the stack and even replace Golgi cisternae within a few hours. These results indicate that although Golgi stacking is a highly complicated process involving a large number of adhesive and regulatory proteins, the overriding principle of a Golgi stack assembly is likely to be quite simple. From this simplified perspective, we propose a model, based on cisternal adhesion and cisternal maturation as the two core principles, illustrating how the most ancient form of Golgi stacking might have occurred using only weak cisternal adhesive processes because of the differential between the rate of influx and outflux of membrane transport through the Golgi. PMID:24449908

Manifold gasket accommodating differential movement of fuel cell stack

DOEpatents

Kelley, Dana A.; Farooque, Mohammad

2007-11-13

A gasket for use in a fuel cell system having at least one externally manifolded fuel cell stack, for sealing the manifold edge and the stack face. In accordance with the present invention, the gasket accommodates differential movement between the stack and manifold by promoting slippage at interfaces between the gasket and the dielectric and between the gasket and the stack face.

Design and assembly considerations for Redox cells and stacks

NASA Technical Reports Server (NTRS)

Stalnaker, D. K.; Lieberman, A.

1981-01-01

Individual redox flow cells are arranged electrically in series and hydraulically in parallel to form a single assembly called a stack. The hardware currently being tested in the laboratory has an active electrode area of either 310 sq cm or 929 sq cm. Four 310 sq cm stacks, each consisting of 39 active cells, were incorporated into a 1.0 kW preprototype system. The physical design of the stack is very critical to the performance and efficiency of the redox storage sytem. This report will discuss the mechanical aspects of the cell and stack design for the current Redox hardware, with regard to sealing the stack internally as well as externally, minimizing shunt currents and minimizing the electrical resistance of the stack.

Golden-ratio rotated stack-of-stars acquisition for improved volumetric MRI.

PubMed

Zhou, Ziwu; Han, Fei; Yan, Lirong; Wang, Danny J J; Hu, Peng

2017-12-01

To develop and evaluate an improved stack-of-stars radial sampling strategy for reducing streaking artifacts. The conventional stack-of-stars sampling strategy collects the same radial angle for every partition (slice) encoding. In an undersampled acquisition, such an aligned acquisition generates coherent aliasing patterns and introduces strong streaking artifacts. We show that by rotating the radial spokes in a golden-angle manner along the partition-encoding direction, the aliasing pattern is modified, resulting in improved image quality for gridding and more advanced reconstruction methods. Computer simulations were performed and phantom as well as in vivo images for three different applications were acquired. Simulation, phantom, and in vivo experiments confirmed that the proposed method was able to generate images with less streaking artifact and sharper structures based on undersampled acquisitions in comparison with the conventional aligned approach at the same acceleration factors. By combining parallel imaging and compressed sensing in the reconstruction, streaking artifacts were mostly removed with improved delineation of fine structures using the proposed strategy. We present a simple method to reduce streaking artifacts and improve image quality in 3D stack-of-stars acquisitions by re-arranging the radial spoke angles in the 3D partition direction, which can be used for rapid volumetric imaging. Magn Reson Med 78:2290-2298, 2017. © 2017 International Society for Magnetic Resonance in Medicine. © 2017 International Society for Magnetic Resonance in Medicine.

Short protection device for stack of electrolytic cells

DOEpatents

Katz, M.; Schroll, C.R.

1984-11-29

The present invention relates to a device for preventing the electrical shorting of a stack of electrolytic cells during an extended period of operation. The device has application to fuel cell and other electrolytic cell stacks operating in low or high temperature corrosive environments. It is of particular importance for use in a stack of fuel cells operating with molten metal carbonate electrolyte for the production of electric power. Also, the device may have application in similar technology involving stacks of electrolytic cells for electrolysis to decompose chemical compounds.

Synthesis of carbon nanotubes from palm oil on stacking and non-stacking substrate by thermal-CVD method

NASA Astrophysics Data System (ADS)

Robaiah, M.; Rusop, M.; Abdullah, S.; Khusaimi, Z.; Azhan, H.; Fadzlinatul, M. Y.; Salifairus, M. J.; Asli, N. A.

2018-05-01

Palm oil has been used as the carbon source to synthesize carbon nanotubes (CNTs) on silicon substrates using the thermal chemical vapor deposition (CVD) method. Meanwhile, silicon has been applied using two techniques, which are stacked technique and non-stacked technique. The CNTs were grown at the constant time of 30 minutes with various synthesis temperatures of 750 °C, 850 °C and 950 °C. The CNTs were characterized using micro-Raman spectroscopy and field emission scanning electron microscopy (FESEM). It was found that the density, growth rate, diameter and length of the CNTs produced were affected by the synthesis temperature. Moreover, the structure slightly changes were observed between CNTs obtained in SS and NSS. The synthesize temperature of 750 °C was considered as the suitable temperature for the production of CNTs due to low ID/IG ratio, which for stacked is 0.89 and non-stacked are 0.90. The possible explanation for the different morphology of the produced CNTs was also discussed.

Co-flow planar SOFC fuel cell stack

DOEpatents

Chung, Brandon W.; Pham, Ai Quoc; Glass, Robert S.

2004-11-30

A co-flow planar solid oxide fuel cell stack with an integral, internal manifold and a casing/holder to separately seal the cell. This construction improves sealing and gas flow, and provides for easy manifolding of cell stacks. In addition, the stack construction has the potential for an improved durability and operation with an additional increase in cell efficiency. The co-flow arrangement can be effectively utilized in other electrochemical systems requiring gas-proof separation of gases.

Subcritical water extraction of alkaloids in Sophora flavescens Ait. and determination by capillary electrophoresis with field-amplified sample stacking.

PubMed

Wang, Haiyan; Lu, Yuchao; Chen, Jie; Li, Junchao; Liu, Shuhui

2012-01-25

The extraction and determination of cytisine, sophocarpine, matrine, sophoridine and oxymatrine in Sophora flavescens Ait. were performed using subcritical water extraction and capillary electrophoresis with field-amplified sample stacking. The effects of extraction temperature, pressure, time and cycle number on the extraction yields were investigated systematically for accelerated solvent extraction with ethanol (ASE) and accelerated solvent extraction with water (subcritical water extraction, SWE). The extraction yields obtained using SWE, ASE, water ultrasonic extraction and chloroform soaking extraction methods were compared. The electrophoresis separation buffer was monosodium phosphate (pH 3.0; 110 mM)-isopropanol (85:15, v/v). The effect of phosphoric acid added to the sample matrix on the reproducibility of the peak heights of the analytes was also examined. Cytisine, sophoridine and oxymatrine showed good linearity (R(2)>0.999) within 0.125-4.0 μg/mL, and sophocarpine and matrine exhibited good linearity (R(2)>0.998) within 0.0625-2.0 μg/mL, with the detection limits in the range of 0.004-0.0013 μg/mL. The five alkaloid contents in medicinal plants from different sources and Sophora instant granule were determined and compared. Copyright © 2011 Elsevier B.V. All rights reserved.

Stacking interactions and DNA intercalation

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

Li, Dr. Shen; Cooper, Valentino R; Thonhauser, Prof. Timo

2009-01-01

The relationship between stacking interactions and the intercalation of proflavine and ellipticine within DNA is investigated using a nonempirical van der Waals density functional for the correlation energy. Our results, employing a binary stack model, highlight fundamental, qualitative differences between base-pair base-pair interactions and that of the stacked intercalator base pair system. Most notable result is the paucity of torque which so distinctively defines the Twist of DNA. Surprisingly, this model, when combined with a constraint on the twist of the surrounding base-pair steps to match the observed unwinding of the sugar-phosphate backbone, was sufficient for explaining the experimentally observedmore » proflavine intercalator configuration. Our extensive mapping of the potential energy surface of base-pair intercalator interactions can provide valuable information for future nonempirical studies of DNA intercalation dynamics.« less

Map showing locations and statistical parameters of beach and offshore sand samples, Tutuila Island, American Samoa

USGS Publications Warehouse

Dingler, J.R.; Carlson, D.V.; Sallenger, A.H.

1987-01-01

In April 1985, sand samples were collected from many of the beaches on Tutuila Island, American Samoa, and in July 1985, three bays were surveyed using side-scan sonar and shallow seismic profiling. During that second trip, scuba divers collected sand samples from the surveyed areas. Dingler and others (1986) describes the study; this report presents the grain-size and composition data for the onshore and offshore sand samples. Locations of the onshore samples are plotted on the map of the island, which is reproduced from Normark and others (1985); locations of most of the offshore samples and side-scan sonar interpretations made during the study are plotted on enlargements (A and B, respectively) of Fagaitua and Nua-seetaga Bays. Lam Yuen (1981), U.S. Army Corps of Engineers (1980), and Sea Engineering Services Inc. (1980) provide additional information pertaining to the island's beaches.

Stacking Up

ERIC Educational Resources Information Center

Naylor, Jim

2005-01-01

Chimneys and stacks appear to be strong and indestructible, but chimneys begin to deteriorate from the moment they are built. Early on, no signs are apparent; but deterioration accelerates in subsequent years, and major repairs are soon needed instead of minor maintenance. With proper attention, most structures can be repaired and continue to…

Electric utility acid fuel cell stack technology advancement

NASA Astrophysics Data System (ADS)

Congdon, J. V.; Goller, G. J.; Greising, G. J.; Obrien, J. J.; Randall, S. A.; Sandelli, G. J.; Breault, R. D.; Austin, G. W.; Bopse, S.; Coykendall, R. D.

1984-11-01

The principal effort under this program was directed at the fuel cell stack technology required to accomplish the initial feasibility demonstrations of increased cell stack operating pressures and temperatures, increased cell active area, incorporation of the ribbed substrate cell configuration at the bove conditions, and the introduction of higher performance electrocatalysts. The program results were successful with the primary accomplishments being: (1) fabrication of 10 sq ft ribbed substrate, cell components including higher performing electrocatalysts; (2) assembly of a 10 sq ft, 30-cell short stack; and (3) initial test of this stack at 120 psia and 405 F. These accomplishments demonstrate the feasibility of fabricating and handling large area cells using materials and processes that are oriented to low cost manufacture. An additional accomplishment under the program was the testing of two 3.7 sq ft short stacks at 12 psia/405 F to 5400 and 4500 hours respectively. These tests demonstrate the durability of the components and the cell stack configuration to a nominal 5000 hours at the higher pressure and temperature condition planned for the next electric utility power plant.

Electric utility acid fuel cell stack technology advancement

NASA Technical Reports Server (NTRS)

Congdon, J. V.; Goller, G. J.; Greising, G. J.; Obrien, J. J.; Randall, S. A.; Sandelli, G. J.; Breault, R. D.; Austin, G. W.; Bopse, S.; Coykendall, R. D.

1984-01-01

The principal effort under this program was directed at the fuel cell stack technology required to accomplish the initial feasibility demonstrations of increased cell stack operating pressures and temperatures, increased cell active area, incorporation of the ribbed substrate cell configuration at the bove conditions, and the introduction of higher performance electrocatalysts. The program results were successful with the primary accomplishments being: (1) fabrication of 10 sq ft ribbed substrate, cell components including higher performing electrocatalysts; (2) assembly of a 10 sq ft, 30-cell short stack; and (3) initial test of this stack at 120 psia and 405 F. These accomplishments demonstrate the feasibility of fabricating and handling large area cells using materials and processes that are oriented to low cost manufacture. An additional accomplishment under the program was the testing of two 3.7 sq ft short stacks at 12 psia/405 F to 5400 and 4500 hours respectively. These tests demonstrate the durability of the components and the cell stack configuration to a nominal 5000 hours at the higher pressure and temperature condition planned for the next electric utility power plant.

Investigations of stacking fault density in perpendicular recording media

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

Piramanayagam, S. N., E-mail: prem-SN@dsi.a-star.edu.sg; Varghese, Binni; Yang, Yi

In magnetic recording media, the grains or clusters reverse their magnetization over a range of reversal field, resulting in a switching field distribution. In order to achieve high areal densities, it is desirable to understand and minimize such a distribution. Clusters of grains which contain stacking faults (SF) or fcc phase have lower anisotropy, an order lower than those without them. It is believed that such low anisotropy regions reverse their magnetization at a much lower reversal field than the rest of the material with a larger anisotropy. Such clusters/grains cause recording performance deterioration, such as adjacent track erasure andmore » dc noise. Therefore, the observation of clusters that reverse at very low reversal fields (nucleation sites, NS) could give information on the noise and the adjacent track erasure. Potentially, the observed clusters could also provide information on the SF. In this paper, we study the reversal of nucleation sites in granular perpendicular media based on a magnetic force microscope (MFM) methodology and validate the observations with high resolution cross-section transmission electron microscopy (HRTEM) measurements. Samples, wherein a high anisotropy CoPt layer was introduced to control the NS or SF in a systematic way, were evaluated by MFM, TEM, and magnetometry. The magnetic properties indicated that the thickness of the CoPt layer results in an increase of nucleation sites. TEM measurements indicated a correlation between the thickness of CoPt layer and the stacking fault density. A clear correlation was also observed between the MFM results, TEM observations, and the coercivity and nucleation field of the samples, validating the effectiveness of the proposed method in evaluating the nucleation sites which potentially arise from stacking faults.« less

A Late Pleistocene sea level stack

NASA Astrophysics Data System (ADS)

Spratt, R. M.; Lisiecki, L. E.

2015-08-01

Late Pleistocene sea level has been reconstructed from ocean sediment core data using a wide variety of proxies and models. However, the accuracy of individual reconstructions is limited by measurement error, local variations in salinity and temperature, and assumptions particular to each technique. Here we present a sea level stack (average) which increases the signal-to-noise ratio of individual reconstructions. Specifically, we perform principal component analysis (PCA) on seven records from 0-430 ka and five records from 0-798 ka. The first principal component, which we use as the stack, describes ~80 % of the variance in the data and is similar using either five or seven records. After scaling the stack based on Holocene and Last Glacial Maximum (LGM) sea level estimates, the stack agrees to within 5 m with isostatically adjusted coral sea level estimates for Marine Isotope Stages 5e and 11 (125 and 400 ka, respectively). When we compare the sea level stack with the δ18O of benthic foraminifera, we find that sea level change accounts for about ~40 % of the total orbital-band variance in benthic δ18O, compared to a 65 % contribution during the LGM-to-Holocene transition. Additionally, the second and third principal components of our analyses reflect differences between proxy records associated with spatial variations in the δ18O of seawater.

An empirical comparison of respondent-driven sampling, time location sampling, and snowball sampling for behavioral surveillance in men who have sex with men, Fortaleza, Brazil.

PubMed

Kendall, Carl; Kerr, Ligia R F S; Gondim, Rogerio C; Werneck, Guilherme L; Macena, Raimunda Hermelinda Maia; Pontes, Marta Kerr; Johnston, Lisa G; Sabin, Keith; McFarland, Willi

2008-07-01

Obtaining samples of populations at risk for HIV challenges surveillance, prevention planning, and evaluation. Methods used include snowball sampling, time location sampling (TLS), and respondent-driven sampling (RDS). Few studies have made side-by-side comparisons to assess their relative advantages. We compared snowball, TLS, and RDS surveys of men who have sex with men (MSM) in Forteleza, Brazil, with a focus on the socio-economic status (SES) and risk behaviors of the samples to each other, to known AIDS cases and to the general population. RDS produced a sample with wider inclusion of lower SES than snowball sampling or TLS-a finding of health significance given the majority of AIDS cases reported among MSM in the state were low SES. RDS also achieved the sample size faster and at lower cost. For reasons of inclusion and cost-efficiency, RDS is the sampling methodology of choice for HIV surveillance of MSM in Fortaleza.

Stacked Average Far-infrared Spectrum of Dusty Star-forming Galaxies from the Herschel/SPIRE Fourier Transform Spectrometer

NASA Astrophysics Data System (ADS)

Wilson, Derek; Cooray, Asantha; Nayyeri, Hooshang; Bonato, Matteo; Bradford, Charles M.; Clements, David L.; De Zotti, Gianfranco; Díaz-Santos, Tanio; Farrah, Duncan; Magdis, Georgios; Michałowski, Michał J.; Pearson, Chris; Rigopoulou, Dimitra; Valtchanov, Ivan; Wang, Lingyu; Wardlow, Julie

2017-10-01

We present stacked average far-infrared spectra of a sample of 197 dusty star-forming galaxies (DSFGs) at 0.005< z< 4 using about 90% of the Herschel Space Observatory SPIRE Fourier Transform Spectrometer (FTS) extragalactic data archive based on 3.5 years of science operations. These spectra explore an observed-frame 447-1568 GHz frequency range, allowing us to observe the main atomic and molecular lines emitted by gas in the interstellar medium. The sample is subdivided into redshift bins, and a subset of the bins are stacked by infrared luminosity as well. These stacked spectra are used to determine the average gas density and radiation field strength in the photodissociation regions (PDRs) of DSFGs. For the low-redshift sample, we present the average spectral line energy distributions of CO and H2O rotational transitions and consider PDR conditions based on observed [C I] 370 and 609 μm, and CO (7-6) lines. For the high-z (0.8< z< 4) sample, PDR models suggest a molecular gas distribution in the presence of a radiation field that is at least a factor of 103 larger than the Milky Way and with a neutral gas density of roughly {10}4.5-{10}5.5 cm-3. The corresponding PDR models for the low-z sample suggest a UV radiation field and gas density comparable to those at high-z. Given the challenges in obtaining adequate far-infrared observations, the stacked average spectra we present here will remain the measurements with the highest signal-to-noise ratio for at least a decade and a half until the launch of the next far-infrared facility. Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA.

Morphological spot counting from stacked images for automated analysis of gene copy numbers by fluorescence in situ hybridization.

PubMed

Grigoryan, Artyom M; Dougherty, Edward R; Kononen, Juha; Bubendorf, Lukas; Hostetter, Galen; Kallioniemi, Olli

2002-01-01

Fluorescence in situ hybridization (FISH) is a molecular diagnostic technique in which a fluorescent labeled probe hybridizes to a target nucleotide sequence of deoxyribose nucleic acid. Upon excitation, each chromosome containing the target sequence produces a fluorescent signal (spot). Because fluorescent spot counting is tedious and often subjective, automated digital algorithms to count spots are desirable. New technology provides a stack of images on multiple focal planes throughout a tissue sample. Multiple-focal-plane imaging helps overcome the biases and imprecision inherent in single-focal-plane methods. This paper proposes an algorithm for global spot counting in stacked three-dimensional slice FISH images without the necessity of nuclei segmentation. It is designed to work in complex backgrounds, when there are agglomerated nuclei, and in the presence of illumination gradients. It is based on the morphological top-hat transform, which locates intensity spikes on irregular backgrounds. After finding signals in the slice images, the algorithm groups these together to form three-dimensional spots. Filters are employed to separate legitimate spots from fluorescent noise. The algorithm is set in a comprehensive toolbox that provides visualization and analytic facilities. It includes simulation software that allows examination of algorithm performance for various image and algorithm parameter settings, including signal size, signal density, and the number of slices.

Vertical melting of a stack of membranes

NASA Astrophysics Data System (ADS)

Borelli, M. E. S.; Kleinert, H.; Schakel, A. M. J.

2001-02-01

A stack of tensionless membranes with nonlinear curvature energy and vertical harmonic interaction is studied. At low temperatures, the system forms a lamellar phase. At a critical temperature, the stack disorders vertically in a melting-like transition.

Slip-stacking Dynamics for High-Power Proton Beams at Fermilab

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

Eldred, Jeffrey Scott

Slip-stacking is a particle accelerator configuration used to store two particle beams with different momenta in the same ring. The two beams are longitudinally focused by two radiofrequency (RF) cavities with a small frequency difference between them. Each beam is synchronized to one RF cavity and perturbed by the other RF cavity. Fermilab uses slip-stacking in the Recycler so as to double the power of the 120 GeV proton beam in the Main Injector. This dissertation investigates the dynamics of slip-stacking beams analytically, numerically and experimentally. In the analytic analysis, I find the general trajectory of stable slip-stacking particles andmore » identify the slip-stacking parametric resonances. In the numerical analysis, I characterize the stable phase-space area and model the particle losses. In particular, I evaluate the impact of upgrading the Fermilab Booster cycle-rate from 15 Hz to 20 Hz as part of the Proton Improvement Plan II (PIP-II). The experimental analysis is used to verify my approach to simulating slip-stacking loss. I design a study for measuring losses from the longitudinal single-particle dynamics of slip-stacking as a function of RF cavity voltage and RF frequency separation. I further propose the installation of a harmonic RF cavity and study the dynamics of this novel slip-stacking configuration. I show the harmonic RF cavity cancels out parametric resonances in slip-stacking, reduces emittance growth during slip-stacking, and dramatically enhances the stable phase-space area. The harmonic cavity is expected to reduce slip-stacking losses to far exceed PIP-II requirements. These results raise the possibility of extending slip-stacking beyond the PIP-II era.« less

Multilayer Piezoelectric Stack Actuator Characterization

NASA Technical Reports Server (NTRS)

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

2008-01-01

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.

Stacking fault effects in Mg-doped GaN

NASA Astrophysics Data System (ADS)

Schmidt, T. M.; Miwa, R. H.; Orellana, W.; Chacham, H.

2002-01-01

First-principles total energy calculations are performed to investigate the interaction of a stacking fault with a p-type impurity in both zinc-blende and wurtzite GaN. For both structures we find that, in the presence of a stacking fault, the impurity level is a more localized state in the band gap. In zinc-blende GaN, the minimum energy position of the substitutional Mg atom is at the plane of the stacking fault. In contrast, in wurtzite GaN the substitutional Mg atom at the plane of the stacking fault is a local minimum and the global minimum is the substitutional Mg far from the fault. This behavior can be understood as a packing effect which induces a distinct strain relief process, since the local structure of the stacking fault in zinc-blende GaN is similar to fault-free wurtzite GaN and vice-versa.

Characterization of Piezoelectric Stacks for Space Applications

NASA Technical Reports Server (NTRS)

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

2008-01-01

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.

Dynamic stability of stacked disk type flywheels

NASA Astrophysics Data System (ADS)

Younger, F. C.

1981-04-01

A flywheel assembly formed from adhesively bonded stacked fiber composite disks was analyzed. The stiffness and rigidity of the assembly required to prevent uncontrolled growth in the deformations due to centrifugal force was determined. It is shown that stacked disk type flywheels become unstable when the speed exceeds a critical value. This critical value of speed depends upon the stiffness of the bonded attachments between the disks. It is found that elastomeric bonds do not provide adequate stiffness to insure dynamic stability for high speed stacked disk type flywheels.

Optical activity in chiral stacks of 2D semiconductors

NASA Astrophysics Data System (ADS)

Poshakinskiy, Alexander V.; Kazanov, Dmitrii R.; Shubina, Tatiana V.; Tarasenko, Sergey A.

2018-03-01

We show that the stacks of two-dimensional semiconductor crystals with the chiral packing exhibit optical activity and circular dichroism. We develop a microscopic theory of these phenomena in the spectral range of exciton transitions that takes into account the spin-dependent hopping of excitons between the layers in the stack and the interlayer coupling of excitons via electromagnetic field. For the stacks of realistic two-dimensional semiconductors such as transition metal dichalcogenides, we calculate the rotation and ellipticity angles of radiation transmitted through such structures. The angles are resonantly enhanced at the frequencies of both bright and dark exciton modes in the stack. We also study the photoluminescence of chiral stacks and show that it is circularly polarized.

Design trade-offs among shunt current, pumping loss and compactness in the piping system of a multi-stack vanadium flow battery

NASA Astrophysics Data System (ADS)

Ye, Qiang; Hu, Jing; Cheng, Ping; Ma, Zhiqi

2015-11-01

Trade-off between shunt current loss and pumping loss is a major challenge in the design of the electrolyte piping network in a flow battery system. It is generally recognized that longer and thinner ducts are beneficial to reduce shunt current but detrimental to minimize pumping power. Base on the developed analog circuit model and the flow network model, we make case studies of multi-stack vanadium flow battery piping systems and demonstrate that both shunt current and electrolyte flow resistance can be simultaneously minimized by using longer and thicker ducts in the piping network. However, extremely long and/or thick ducts lead to a bulky system and may be prohibited by the stack structure. Accordingly, the intrinsic design trade-off is between system efficiency and compactness. Since multi-stack configurations bring both flexibility and complexity to the design process, we perform systematic comparisons among representative piping system designs to illustrate the complicated trade-offs among numerous parameters including stack number, intra-stack channel resistance and inter-stack pipe resistance. As the final design depends on various technical and economical requirements, this paper aims to provide guidelines rather than solutions for designers to locate the optimal trade-off points according to their specific cases.

Evaluation of a CFD Method for Aerodynamic Database Development using the Hyper-X Stack Configuration

NASA Technical Reports Server (NTRS)

Parikh, Paresh; Engelund, Walter; Armand, Sasan; Bittner, Robert

2004-01-01

A computational fluid dynamic (CFD) study is performed on the Hyper-X (X-43A) Launch Vehicle stack configuration in support of the aerodynamic database generation in the transonic to hypersonic flow regime. The main aim of the study is the evaluation of a CFD method that can be used to support aerodynamic database development for similar future configurations. The CFD method uses the NASA Langley Research Center developed TetrUSS software, which is based on tetrahedral, unstructured grids. The Navier-Stokes computational method is first evaluated against a set of wind tunnel test data to gain confidence in the code s application to hypersonic Mach number flows. The evaluation includes comparison of the longitudinal stability derivatives on the complete stack configuration (which includes the X-43A/Hyper-X Research Vehicle, the launch vehicle and an adapter connecting the two), detailed surface pressure distributions at selected locations on the stack body and component (rudder, elevons) forces and moments. The CFD method is further used to predict the stack aerodynamic performance at flow conditions where no experimental data is available as well as for component loads for mechanical design and aero-elastic analyses. An excellent match between the computed and the test data over a range of flow conditions provides a computational tool that may be used for future similar hypersonic configurations with confidence.

Extensive radioactive characterization of a phosphogypsum stack in SW Spain: 226Ra, 238U, 210Po concentrations and 222Rn exhalation rate.

PubMed

Abril, José-María; García-Tenorio, Rafael; Manjón, Guillermo

2009-05-30

Phosphogypsum (PG) is a by-product of the phosphate fertilizer industries that contains relatively high concentrations of uranium series radionuclides. The US-EPA regulates the agriculture use of PG, attending to its (226)Ra content and to the (222)Rn exhalation rate from inactive stacks. Measurements of (222)Rn exhalation rates in PG stacks typically show a large and still poorly understood spatial and temporal variability, and the published data are scarce. This work studies an inactive PG stack in SW Spain of about 0.5 km(2) from where PG can be extracted for agriculture uses, and an agriculture soil 75 km apart, being representative of the farms to be amended with PG. Activity concentrations of (226)Ra, (238)U and (210)Po have been measured in 30 PG samples (0-90 cm horizon) allowing for the construction of maps with spatial distributions in the PG stack and for the characterization of the associated PG inputs to agriculture soils. Averaged (226)Ra concentrations for the stack were 730+/-60 Bq kg(-1) (d.w.), over the US-EPA limit of 370 Bq kg(-1). (222)Rn exhalation rate has been measured by the charcoal canister method in 49 sampling points with 3 canisters per sampling point. Values in PG stack were under the US-EPA limit of 2600 Bq m(-2)h(-1), but they were one order of magnitude higher than those found in the agriculture soil. Variability in radon emissions has been studied at different spatial scales. Radon exhalation rates were correlated with (226)Ra concentrations and daily potential evapotranspiration (ETo). They increased with ETo in agriculture soils, but showed an opposite behaviour in the PG stack.

Identification of Clusters of Foot Pain Location in a Community Sample.

PubMed

Gill, Tiffany K; Menz, Hylton B; Landorf, Karl B; Arnold, John B; Taylor, Anne W; Hill, Catherine L

2017-12-01

To identify foot pain clusters according to pain location in a community-based sample of the general population. This study analyzed data from the North West Adelaide Health Study. Data were obtained between 2004 and 2006, using computer-assisted telephone interviewing, clinical assessment, and self-completed questionnaire. The location of foot pain was assessed using a diagram during the clinical assessment. Hierarchical cluster analysis was undertaken to identify foot pain location clusters, which were then compared in relation to demographics, comorbidities, and podiatry services utilization. There were 558 participants with foot pain (mean age 54.4 years, 57.5% female). Five clusters were identified: 1 with predominantly arch and ball pain (26.8%), 1 with rearfoot pain (20.9%), 1 with heel pain (13.3%), and 2 with predominantly forefoot, toe, and nail pain (28.3% and 10.7%). Each cluster was distinct in age, sex, and comorbidity profile. Of the two clusters with predominantly forefoot, toe, and nail pain, one of them had a higher proportion of men and those classified as obese, had diabetes mellitus, and used podiatry services (30%), while the other was comprised of a higher proportion of women who were overweight and reported less use of podiatry services (17.5%). Five clusters of foot pain according to pain location were identified, all with distinct age, sex, and comorbidity profiles. These findings may assist in the identification of individuals at risk for developing foot pain and in the development of targeted preventive strategies and treatments. © 2017, American College of Rheumatology.

Physical Sciences Laboratory 1 Rooftop Stack Mixing Study

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

Flaherty, Julia E.; Antonio, Ernest J.

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 ofmore » 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).« less

Seasonal rationalization of river water quality sampling locations: a comparative study of the modified Sanders and multivariate statistical approaches.

PubMed

Varekar, Vikas; Karmakar, Subhankar; Jha, Ramakar

2016-02-01

The design of surface water quality sampling location is a crucial decision-making process for rationalization of monitoring network. The quantity, quality, and types of available dataset (watershed characteristics and water quality data) may affect the selection of appropriate design methodology. The modified Sanders approach and multivariate statistical techniques [particularly factor analysis (FA)/principal component analysis (PCA)] are well-accepted and widely used techniques for design of sampling locations. However, their performance may vary significantly with quantity, quality, and types of available dataset. In this paper, an attempt has been made to evaluate performance of these techniques by accounting the effect of seasonal variation, under a situation of limited water quality data but extensive watershed characteristics information, as continuous and consistent river water quality data is usually difficult to obtain, whereas watershed information may be made available through application of geospatial techniques. A case study of Kali River, Western Uttar Pradesh, India, is selected for the analysis. The monitoring was carried out at 16 sampling locations. The discrete and diffuse pollution loads at different sampling sites were estimated and accounted using modified Sanders approach, whereas the monitored physical and chemical water quality parameters were utilized as inputs for FA/PCA. The designed optimum number of sampling locations for monsoon and non-monsoon seasons by modified Sanders approach are eight and seven while that for FA/PCA are eleven and nine, respectively. Less variation in the number and locations of designed sampling sites were obtained by both techniques, which shows stability of results. A geospatial analysis has also been carried out to check the significance of designed sampling location with respect to river basin characteristics and land use of the study area. Both methods are equally efficient; however, modified Sanders

The multi-scattering model for calculations of positron spatial distribution in the multilayer stacks, useful for conventional positron measurements

NASA Astrophysics Data System (ADS)

Dryzek, Jerzy; Siemek, Krzysztof

2013-08-01

The spatial distribution of positrons emitted from radioactive isotopes into stacks or layered samples is a subject of the presented report. It was found that Monte Carlo (MC) simulations using GEANT4 code are not able to describe correctly the experimental data of the positron fractions in stacks. The mathematical model was proposed for calculations of the implantation profile or positron fractions in separated layers or foils being components of a stack. The model takes into account only two processes, i.e., the positron absorption and backscattering at interfaces. The mathematical formulas were applied in the computer program called LYS-1 (layers profile analysis). The theoretical predictions of the model were in the good agreement with the results of the MC simulations for the semi infinite sample. The experimental verifications of the model were performed on the symmetrical and non-symmetrical stacks of different foils. The good agreement between the experimental and calculated fractions of positrons in components of a stack was achieved. Also the experimental implantation profile obtained using the depth scanning of positron implantation technique is very well described by the theoretical profile obtained within the proposed model. The LYS-1 program allows us also to calculate the fraction of positrons which annihilate in the source, which can be useful in the positron spectroscopy.

40 CFR 52.2633 - Stack height regulations.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 4 2010-07-01 2010-07-01 false Stack height regulations. 52.2633 Section 52.2633 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS... with the “Guideline for Determination of Good Engineering Practice Stack Height (Technical Support...

40 CFR 52.2384 - Stack height review.

Code of Federal Regulations, 2010 CFR

2010-07-01

....2384 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED... affected by stack height credits greater than good engineering practice or any other prohibited dispersion... than ‘good engineering practice’ stack height or from using ‘other dispersion techniques.’ ” Thus...

Application of scanning angle Raman spectroscopy for determining the location of buried polymer interfaces with tens of nanometer precision

DOE PAGES

Damin, Craig A.; Nguyen, Vy H. T.; Niyibizi, Auguste S.; ...

2015-02-11

In this study, near-infrared scanning angle (SA) Raman spectroscopy was utilized to determine the interface location in bilayer films (a stack of two polymer layers) of polystyrene (PS) and polycarbonate (PC). Finite-difference-time-domain (FDTD) calculations of the sum square electric field (SSEF) for films with total bilayer thicknesses of 1200–3600 nm were used to construct models for simultaneously measuring the film thickness and the location of the buried interface between the PS and PC layers. Samples with total thicknesses of 1320, 1890, 2300, and 2750 nm and varying PS/PC interface locations were analyzed using SA Raman spectroscopy. Comparing SA Raman spectroscopymore » and optical profilometry measurements, the average percent difference in the total bilayer thickness was 2.0% for films less than ~2300 nm thick. The average percent difference in the thickness of the PS layer, which reflects the interface location, was 2.5% when the PS layer was less than ~1800 nm. SA Raman spectroscopy has been shown to be a viable, non-destructive method capable of determining the total bilayer thickness and buried interface location for bilayer samples consisting of thin polymer films with comparable indices of refraction.« less

Preliminary study on rotary ultrasonic machining of CFRP/Ti stacks.

PubMed

Cong, W L; Pei, Z J; Treadwell, C

2014-08-01

Reported drilling methods for CFRP/Ti stacks include twist drilling, end milling, core grinding, and their derived methods. The literature does not have any report on drilling of CFRP/Ti stacks using rotary ultrasonic machining (RUM). This paper, for the first time, reports a study on drilling of CFRP/Ti stacks using RUM. It also compares results on drilling of CFRP/Ti stacks using RUM with reported results on drilling of CFRP/Ti stacks using other methods. When drilling CFRP/Ti stacks using RUM, cutting force, torque, and CFRP surface roughness were lower, hole size variation was smaller, CFRP groove depth was smaller, tool life was longer, and there was no obvious Ti exit burr and CFRP entrance delamination. Ti surface roughness when drilling of CFRP/Ti stacks using RUM was about the same as those when using other methods. Copyright © 2014 Elsevier B.V. All rights reserved.

81. THREE ADDITIONAL BLACK AND WHITE VIDEO MONITORS LOCATED IMMEDIATELY ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

81. THREE ADDITIONAL BLACK AND WHITE VIDEO MONITORS LOCATED IMMEDIATELY WEST OF THOSE IN CA-133-1-A-80. COMPLEX SAFETY WARNING LIGHTS FOR SLC-3E (PAD 2) AND BLDG. 763 (LOB) LOCATED ABOVE MONITOR 3; GREEN LIGHTS ON BOTTOM OF EACH STACK ILLUMINATED. LEFT TO RIGHT BELOW MONITORS: ACCIDENT REPORTING EMERGENCY NOTIFICATION SYSTEM TELEPHONE, ATLAS H FUEL COUNTER, AND DIGITAL COUNTDOWN CLOCK. - Vandenberg Air Force Base, Space Launch Complex 3, Launch Operations Building, Napa & Alden Roads, Lompoc, Santa Barbara County, CA

Identification of indicator congeners and evaluation of emission pattern of polychlorinated naphthalenes in industrial stack gas emissions by statistical analyses.

PubMed

Liu, Guorui; Cai, Zongwei; Zheng, Minghui; Jiang, Xiaoxu; Nie, Zhiqiang; Wang, Mei

2015-01-01

Identifying marker congeners of unintentionally produced polychlorinated naphthalenes (PCNs) from industrial thermal sources might be useful for predicting total PCN (∑2-8PCN) emissions by the determination of only indicator congeners. In this study, potential indicator congeners were identified based on the PCN data in 122 stack gas samples from over 60 plants involved in more than ten industrial thermal sources reported in our previous case studies. Linear regression analyses identified that the concentrations of CN27/30, CN52/60, and CN66/67 correlated significantly with ∑2-8PCN (R(2)=0.77, 0.80, and 0.58, respectively; n=122, p<0.05), which might be good candidates for indicator congeners. Equations describing relationships between indicators and ∑2-8PCN were established. The linear regression analyses involving 122 samples showed that the relationships between the indicator congeners and ∑2-8PCN were not significantly affected by factors such as industry types, raw materials used, or operating conditions. Hierarchical cluster analysis and similarity calculations for the 122 stack gas samples were adopted to group those samples and evaluating their similarity and difference based on the PCN homolog distributions from different industrial thermal sources. Generally, the fractions of less chlorinated homologs comprised of di-, tri-, and tetra-homologs were much higher than that of more chlorinated homologs for up to 111 stack gas samples contained in group 1 and 2, which indicating the dominance of lower chlorinated homologs in stack gas from industrial thermal sources. Copyright © 2014 Elsevier Ltd. All rights reserved.

Ultra-sensitive speciation analysis of mercury by CE-ICP-MS together with field-amplified sample stacking injection and dispersive solid-phase extraction.

PubMed

Chen, YiQuan; Cheng, Xian; Mo, Fan; Huang, LiMei; Wu, Zujian; Wu, Yongning; Xu, LiangJun; Fu, FengFu

2016-04-01

A simple dispersive solid-phase extraction (DSPE) used to extract and preconcentrate ultra-trace MeHg, EtHg and Hg(2+) from water sample, and a sensitive method for the simultaneous analysis of MeHg, EtHg and Hg(2+) by using capillary electrophoresis-inductively coupled plasma mass spectrometry (CE-ICP-MS) with field-amplified sample stacking injection (FASI) were first reported in this study. The DSPE used thiol cotton particles as adsorbent, and is simple and effective. It can be used to extract and preconcentrate ultra-trace mercury compounds in water samples within 30 min with a satisfied recovery and no mercury species alteration during the process. The FASI enhanced the sensitivity of CE-ICP-MS with 25-fold, 29-fold and 27-fold for MeHg, EtHg and Hg(2+) , respectively. Using FASI-CE-ICP-MS together with DSPE, we have successfully determined ultra-trace MeHg, EtHg and Hg(2+) in tap water with a limits of quantification (LOQs) of 0.26-0.45 pg/mL, an RSD (n = 3) < 6% and a recovery of 92-108%. Ultra-high sensitivity, as well as much less sample and reagent consumption and low operating cost, make our method a valuable technique to the speciation analysis of ultra-trace mercury. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Finite element analysis of multilayer DEAP stack-actuators

NASA Astrophysics Data System (ADS)

Kuhring, Stefan; Uhlenbusch, Dominik; Hoffstadt, Thorben; Maas, Jürgen

2015-04-01

Dielectric elastomers (DE) are thin polymer films belonging to the class of electroactive polymers (EAP). They are coated with compliant and conductive electrodes on each side, which make them performing a relative high amount of deformation with considerable force generation under the influence of an electric field. Because the realization of high electric fields with a limited voltage level requests single layer polymer films to be very thin, novel multilayer actuators are utilized to increase the absolute displacement and force. In case of a multilayer stack-actuator, many actuator films are mechanically stacked in series and electrically connected in parallel. Because there are different ways to design such a stack-actuator, this contribution considers an optimization of some design parameters using the finite element analysis (FEA), whereby the behavior and the actuation of a multilayer dielectric electroactive polymer (DEAP) stack-actuator can be improved. To describe the material behavior, first different material models are compared and necessary material parameters are identified by experiments. Furthermore, a FEA model of a DEAP film is presented, which is expanded to a multilayer DEAP stack-actuator model. Finally, the results of the FEA are discussed and conclusions for design rules of optimized stack-actuators are outlined.

40 CFR 52.1034 - Stack height review.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 4 2010-07-01 2010-07-01 false Stack height review. 52.1034 Section 52.1034 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED... affected by stack height credits greater than good engineering practice or any other prohibited dispersion...

40 CFR 51.164 - Stack height procedures.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 51.164 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS... source's stack height that exceeds good engineering practice or by any other dispersion technique, except... source based on a good engineering practice stack height that exceeds the height allowed by § 51.100(ii...

40 CFR 52.383 - Stack height review.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 3 2010-07-01 2010-07-01 false Stack height review. 52.383 Section 52.383 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED... by stack height credits greater than good engineering practice or any other prohibited dispersion...

40 CFR 51.118 - Stack height provisions.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 2 2010-07-01 2010-07-01 false Stack height provisions. 51.118 Section 51.118 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS REQUIREMENTS FOR PREPARATION, ADOPTION, AND SUBMITTAL OF IMPLEMENTATION PLANS Control Strategy § 51.118 Stack...

A review of polymer electrolyte membrane fuel cell stack testing

NASA Astrophysics Data System (ADS)

Miller, M.; Bazylak, A.

This paper presents an overview of polymer electrolyte membrane fuel cell (PEMFC) stack testing. Stack testing is critical for evaluating and demonstrating the viability and durability required for commercial applications. Single cell performance cannot be employed alone to fully derive the expected performance of PEMFC stacks, due to the non-uniformity in potential, temperature, and reactant and product flow distributions observed in stacks. In this paper, we provide a comprehensive review of the state-of-the art in PEMFC testing. We discuss the main topics of investigation, including single cell vs. stack-level performance, cell voltage uniformity, influence of operating conditions, durability and degradation, dynamic operation, and stack demonstrations. We also present opportunities for future work, including the need to verify the impact of stack size and cell voltage uniformity on performance, determine operating conditions for achieving a balance between electrical efficiency and flooding/dry-out, meet lifetime requirements through endurance testing, and develop a stronger understanding of degradation.

Implementation of Grid Tier 2 and Tier 3 facilities on a Distributed OpenStack Cloud

NASA Astrophysics Data System (ADS)

Limosani, Antonio; Boland, Lucien; Coddington, Paul; Crosby, Sean; Huang, Joanna; Sevior, Martin; Wilson, Ross; Zhang, Shunde

2014-06-01

The Australian Government is making a AUD 100 million investment in Compute and Storage for the academic community. The Compute facilities are provided in the form of 30,000 CPU cores located at 8 nodes around Australia in a distributed virtualized Infrastructure as a Service facility based on OpenStack. The storage will eventually consist of over 100 petabytes located at 6 nodes. All will be linked via a 100 Gb/s network. This proceeding describes the development of a fully connected WLCG Tier-2 grid site as well as a general purpose Tier-3 computing cluster based on this architecture. The facility employs an extension to Torque to enable dynamic allocations of virtual machine instances. A base Scientific Linux virtual machine (VM) image is deployed in the OpenStack cloud and automatically configured as required using Puppet. Custom scripts are used to launch multiple VMs, integrate them into the dynamic Torque cluster and to mount remote file systems. We report on our experience in developing this nation-wide ATLAS and Belle II Tier 2 and Tier 3 computing infrastructure using the national Research Cloud and storage facilities.

The behaviour of stacking fault energy upon interstitial alloying.

PubMed

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

2017-09-11

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.

Fast principal component analysis for stacking seismic data

NASA Astrophysics Data System (ADS)

Wu, Juan; Bai, Min

2018-04-01

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.

Results of Macroinvertebrate Sampling Conducted at 33 SRS Stream Locations, July--August 1993

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

Specht, W.L.

1994-12-01

In order to assess the health of the macroinvertebrate communities of SRS streams, the macroinvertebrate communities at 30 stream locations on SRS were sampled during the summer of 1993, using Hester-Dendy multiplate samplers. In addition, three off-site locations in the Upper Three Runs drainage were sampled in order to assess the potential for impact from off-site activities. In interpreting the data, it is important to recognize that these data were from a single set of collections. Macroinvertebrate communities often undergo considerable temporal variation, and are also greatly influenced by such factors as water depth, water velocity, and available habitat. Thesemore » stations were selected with the intent of developing an on-going sampling program at a smaller number of stations, with the selection of the stations to be based largely upon the results of this preliminary sampling program. When stations within a given stream showed similar results, fewer stations would be sampled in the future. Similarly, if a stream appeared to be perturbed, additional stations or chemical analyses might be added so that the source of the perturbation could be identified. In general, unperturbed streams will contain more taxa than perturbed streams, and the distribution of taxa among orders or families will differ. Some groups of macroinvertebrates, such as Ephemeroptera (mayflies), Plecoptera (stoneflies) and Trichoptera (caddisflies), which are collectively called EPT taxa, are considered to be relatively sensitive to most kinds of stream perturbation; therefore a reduced number of EPT taxa generally indicates that the stream has been subject to chemical or physical stressors. In coastal plain streams, EPT taxa are generally less dominant than in streams with rocky substrates, while Chironomidae (midges) are more abundant. (Abstract Truncated)« less

[Location of semen collection and semen quality: clinic-collected versus home-collected samples].

PubMed

Wang, Wei; Zhong, Zhi-min; Su, Ning; Peng, Ya-ya; Huang, Ting-ting

2014-11-01

To investigate the differences in semen quality between samples collected by masturbation in the clinic and at home. Based on the WHO guidelines, we analyzed the ejaculates collected by masturbation in the clinic and at home from 342 men under infertility assessment and measured the contents of such biochemical markers in the seminal plasma as neutral α-glucosidase, zinc, and fructose. According to the location of semen collection, we divided the samples into two groups, clinic-collected and home-collected, and analyzed the differences in the semen parameters between the two groups with the SPSS 16.0 software. Compared with the clinic-collected semen, the home-collected samples had significantly higher mean values in semen volume (4.0 vs 4.9%), sperm concentration (41 vs 64 x 10(6)/ml), total sperm count (175 vs 270 x 10(6) per ejaculate), progressive sperm motility (40 vs 52%), total count of progressively motile sperm (82 vs 135 x 10(6) per ejaculate) (all P <0.05). No significant differences were found between the two groups in normal sperm morphology (4.0 vs 5.0%) and the contents of neutral α-glucosidase (26 vs 24 mU per ejaculate), zinc (8.0 vs 8.0 μmol per ejaculate), and fructose (62 vs 60 μmol per ejaculate) (all P >0.05). Abnormal sperm concentration (<20 x 10(6)/ml) was observed in significantly fewer of the home-collected samples than the clinic-collected ones (18% [62/342] vs 30% [103/342], P<0.05), and so was abnormal progressive sperm motility (<32%) (64% [219/342] vs 75% [256/342], P<0.05). Our findings show that semen samples collected by masturbation at home has a higher quality than those collected in the clinic. So the location of semen collection should be taken into consideration in infertility investigation.

MR imaging of iliofemoral peripheral vascular calcifications using proton density-weighted, in-phase three-dimensional stack-of-stars gradient echo.

PubMed

Ferreira Botelho, Marcos P; Koktzoglou, Ioannis; Collins, Jeremy D; Giri, Shivraman; Carr, James C; Gupta, NavYash; Edelman, Robert R

2017-06-01

The presence of vascular calcifications helps to determine percutaneous access for interventional vascular procedures and has prognostic value for future cardiovascular events. Unlike CT, standard MRI techniques are insensitive to vascular calcifications. In this prospective study, we tested a proton density-weighted, in-phase (PDIP) three-dimensional (3D) stack-of-stars gradient-echo pulse sequence with approximately 1 mm 3 isotropic spatial resolution at 1.5 Tesla (T) and 3T to detect iliofemoral peripheral vascular calcifications and correlated MR-determined lesion volumes with CT angiography (CTA). The study was approved by the Institutional Review Board. The prototype PDIP stack-of-stars pulse sequence was applied in 12 patients with iliofemoral peripheral vascular calcifications who had undergone CTA. Vascular calcifications were well visualized in all subjects, excluding segments near prostheses or stents. The location, size, and shape of the calcifications were similar to CTA. Quantitative analysis showed excellent correlation (r 2  = 0.84; P < 0.0001) between MR- and CT-based measures of calcification volume. In one subject in whom three pulse sequences were compared, PDIP stack-of-stars outperformed cartesian 3D gradient-echo and point-wise encoding time reduction with radial acquisition (PETRA). In this pilot study, a PDIP 3D stack-of-stars gradient-echo pulse sequence with high spatial resolution provided excellent image quality and accurately depicted the location and volume of iliofemoral vascular calcifications. Magn Reson Med 77:2146-2152, 2017. © 2016 International Society for Magnetic Resonance in Medicine. © 2016 International Society for Magnetic Resonance in Medicine.

The Stack of Yang-Mills Fields on Lorentzian Manifolds

NASA Astrophysics Data System (ADS)

Benini, Marco; Schenkel, Alexander; Schreiber, Urs

2018-03-01

We provide an abstract definition and an explicit construction of the stack of non-Abelian Yang-Mills fields on globally hyperbolic Lorentzian manifolds. We also formulate a stacky version of the Yang-Mills Cauchy problem and show that its well-posedness is equivalent to a whole family of parametrized PDE problems. Our work is based on the homotopy theoretical approach to stacks proposed in Hollander (Isr. J. Math. 163:93-124, 2008), which we shall extend by further constructions that are relevant for our purposes. In particular, we will clarify the concretification of mapping stacks to classifying stacks such as BG con.

Cassette less SOFC stack and method of assembly

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

Meinhardt, Kerry D

2014-11-18

A cassette less SOFC assembly and a method for creating such an assembly. The SOFC stack is characterized by an electrically isolated stack current path which allows welded interconnection between frame portions of the stack. In one embodiment electrically isolating a current path comprises the step of sealing a interconnect plate to a interconnect plate frame with an insulating seal. This enables the current path portion to be isolated from the structural frame an enables the cell frame to be welded together.

Enhanced dynamical stability with harmonic slip stacking

DOE PAGES

Eldred, Jeffrey; Zwaska, Robert

2016-10-26

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 themore » 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. In conclusion, we demonstrate that the harmonic rf cavity can not only reduce particle loss during slip-stacking, but also reduce the final longitudinal emittance.« less

Enhanced dynamical stability with harmonic slip stacking

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

Eldred, Jeffrey; Zwaska, Robert

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 themore » 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. In conclusion, we demonstrate that the harmonic rf cavity can not only reduce particle loss during slip-stacking, but also reduce the final longitudinal emittance.« less

Enumeration of Extended m-Regular Linear Stacks.

PubMed

Guo, Qiang-Hui; Sun, Lisa H; Wang, Jian

2016-12-01

The contact map of a protein fold in the two-dimensional (2D) square lattice has arc length at least 3, and each internal vertex has degree at most 2, whereas the two terminal vertices have degree at most 3. Recently, Chen, Guo, Sun, and Wang studied the enumeration of [Formula: see text]-regular linear stacks, where each arc has length at least [Formula: see text] and the degree of each vertex is bounded by 2. Since the two terminal points in a protein fold in the 2D square lattice may form contacts with at most three adjacent lattice points, we are led to the study of extended [Formula: see text]-regular linear stacks, in which the degree of each terminal point is bounded by 3. This model is closed to real protein contact maps. Denote the generating functions of the [Formula: see text]-regular linear stacks and the extended [Formula: see text]-regular linear stacks by [Formula: see text] and [Formula: see text], respectively. We show that [Formula: see text] can be written as a rational function of [Formula: see text]. For a certain [Formula: see text], by eliminating [Formula: see text], we obtain an equation satisfied by [Formula: see text] and derive the asymptotic formula of the numbers of [Formula: see text]-regular linear stacks of length [Formula: see text].

Fungal Melanins Differ in Planar Stacking Distances

PubMed Central

Casadevall, Arturo; Nakouzi, Antonio; Crippa, Pier R.; Eisner, Melvin

2012-01-01

Melanins are notoriously difficult to study because they are amorphous, insoluble and often associated with other biological materials. Consequently, there is a dearth of structural techniques to study this enigmatic pigment. Current models of melanin structure envision the stacking of planar structures. X ray diffraction has historically been used to deduce stacking parameters. In this study we used X ray diffraction to analyze melanins derived from Cryptococcus neoformans, Aspergillus niger, Wangiella dermatitides and Coprinus comatus. Analysis of melanin in melanized C. neoformans encapsulated cells was precluded by the fortuitous finding that the capsular polysaccharide had a diffraction spectrum that was similar to that of isolated melanin. The capsular polysaccharide spectrum was dominated by a broad non-Bragg feature consistent with origin from a repeating structural motif that may arise from inter-molecular interactions and/or possibly gel organization. Hence, we isolated melanin from each fungal species and compared diffraction parameters. The results show that the inferred stacking distances of fungal melanins differ from that reported for synthetic melanin and neuromelanin, occupying intermediate position between these other melanins. These results suggest that all melanins have a fundamental diffracting unit composed of planar graphitic assemblies that can differ in stacking distance. The stacking peak appears to be a distinguishing universal feature of melanins that may be of use in characterizing these enigmatic pigments. PMID:22359541

Face-to-face stacks of trinuclear gold(I) trihalides with benzene, hexafluorobenzene, and borazine: impact of aromaticity on stacking interactions.

PubMed

Tsipis, Athanassios C; Stalikas, Alexandros V

2013-01-18

The interplay of electrostatics, charge transfer, and dispersion forces contributing to the interaction energies in 1:1, 1:2, and 2:1 binary stacks of the c-Au(3)(μ(2)-X)(3) (X = F, Cl, Br, I) clusters with benzene, hexafluorobenzene, or borazine were investigated by employing a multitude of electronic structure computational techniques. The molecular and electronic structures, stabilities, bonding features, and magnetotropicity of [c-Au(3)(μ(2)-X)(3)](n)(L)(m) (X = halide; L = C(6)H(6), C(6)F(6), B(3)N(3)H(6); n, m ≤ 2) columnar binary stacks have been investigated by DFT calculations employing the M05-2X functional. The novel binary stacks could be considered as the building blocks of extended columnar supramolecular assemblies formulated as {[c-Au(3)(μ(2)-X)(3)](C(6)H(6))}(∞), {[c-Au(3)(μ(2)-X)(3)](2)(C(6)F(6))}(∞), and {[c-Au(3)(μ(2)-X)(3)](B(3)N(3)H(6))(2)}(∞). In all binary stacks, with a few exceptions, the plane of the alternating c-Au(3)(μ(2)-X)(3) and L (C(6)H(6), C(6)F(6), B(3)N(3)H(6)) stacking participants adopt an almost parallel face-to-face (pff) orientation. The observed trends in the intermolecular distances R in the [c-Au(3)(μ(2)-X)(3)](n)(L)(m) (X = halide; L = C(6)H(6), C(6)F(6), B(3)N(3)H(6); n, m ≤ 2) columnar binary stacks are explained by the diverse intermolecular interactions characterizing the stacks, since the three ligands L and the c-Au(3)(μ(2)-X)(3) cyclic trinuclear clusters (CTCs) exhibit diverse physical properties being important determinants of the intermolecular interactions (consisting of covalent, electrostatic, and dispersion forces). The properties considered are the zz tensor components of quadrupole moment, Q(zz), polarizability, α(zz), nucleus-independent chemical shift, NICS(zz)(1), along with the molecular electrostatic potential, MEP(0), and surface area (S). Energy decomposition analysis (EDA) at the revPBE-D3/TZ2P level revealed that the dominant term in the stacking interactions arises mainly

Effective Stack Design in Air Pollution Control.

ERIC Educational Resources Information Center

Clarke, John H.

1968-01-01

Stack design problems fall into two general caterories--(1) those of building re-entry, and (2) those of general area pollution. Extensive research has developed adequate information, available in the literature, to permit effective stack design. A major roadblock to effective design has been the strong belief by architects and engineers that high…

Location tests for biomarker studies: a comparison using simulations for the two-sample case.

PubMed

Scheinhardt, M O; Ziegler, A

2013-01-01

Gene, protein, or metabolite expression levels are often non-normally distributed, heavy tailed and contain outliers. Standard statistical approaches may fail as location tests in this situation. In three Monte-Carlo simulation studies, we aimed at comparing the type I error levels and empirical power of standard location tests and three adaptive tests [O'Gorman, Can J Stat 1997; 25: 269 -279; Keselman et al., Brit J Math Stat Psychol 2007; 60: 267- 293; Szymczak et al., Stat Med 2013; 32: 524 - 537] for a wide range of distributions. We simulated two-sample scenarios using the g-and-k-distribution family to systematically vary tail length and skewness with identical and varying variability between groups. All tests kept the type I error level when groups did not vary in their variability. The standard non-parametric U-test performed well in all simulated scenarios. It was outperformed by the two non-parametric adaptive methods in case of heavy tails or large skewness. Most tests did not keep the type I error level for skewed data in the case of heterogeneous variances. The standard U-test was a powerful and robust location test for most of the simulated scenarios except for very heavy tailed or heavy skewed data, and it is thus to be recommended except for these cases. The non-parametric adaptive tests were powerful for both normal and non-normal distributions under sample variance homogeneity. But when sample variances differed, they did not keep the type I error level. The parametric adaptive test lacks power for skewed and heavy tailed distributions.

Music Preference, Depression, Suicidal Preoccupation, and Personality: Comment on Stack and Gundlach's Papers.

ERIC Educational Resources Information Center

Lester, David; Whipple, Melissa

1996-01-01

In a sample of students (n=93), preference for country and western music was not associated with depression or suicidal preoccupation as has been suggested by Stack and Gundlach. However, preference for heavy metal music was associated with prior suicidal ideation. Stronger associations were found between music preferences and measures of…

Reinforcer control by comparison-stimulus color and location in a delayed matching-to-sample task.

PubMed

Alsop, Brent; Jones, B Max

2008-05-01

Six pigeons were trained in a delayed matching-to-sample task involving bright- and dim-yellow samples on a central key, a five-peck response requirement to either sample, a constant 1.5-s delay, and the presentation of comparison stimuli composed of red on the left key and green on the right key or vice versa. Green-key responses were occasionally reinforced following the dimmer-yellow sample, and red-key responses were occasionally reinforced following the brighter-yellow sample. Reinforcer delivery was controlled such that the distribution of reinforcers across both comparison-stimulus color and comparison-stimulus location could be varied systematically and independently across conditions. Matching accuracy was high throughout. The ratio of left to right side-key responses increased as the ratio of left to right reinforcers increased, the ratio of red to green responses increased as the ratio of red to green reinforcers increased, and there was no interaction between these variables. However, side-key biases were more sensitive to the distribution of reinforcers across key location than were comparison-color biases to the distribution of reinforcers across key color. An extension of Davison and Tustin's (1978) model of DMTS performance fit the data well, but the results were also consistent with an alternative theory of conditional discrimination performance (Jones, 2003) that calls for a conceptually distinct quantitative model.

Transient analysis of a solid oxide fuel cell stack with crossflow configuration

NASA Astrophysics Data System (ADS)

Yuan, P.; Liu, S. F.

2018-05-01

This study investigates the transient response of the cell temperature and current density of a solid oxide fuel cell having 6 stacks with crossflow configuration. A commercial software repeatedly solves the governing equations of each stack, and get the convergent results of the whole SOFC stack. The preliminary results indicate that the average current density of each stack is similar to others, so the power output between different stacks are uniform. Moreover, the average cell temperature among stacks is different, and the central stacks have higher temperature due to its harder heat dissipation. For the operating control, the cell temperature difference among stacks is worth to concern because the temperature difference will be over 10 °C in the analysis case. The increasing of the inlet flow rate of the fuel and air will short the transient state, increase the average current density, and drop the cell temperature difference among the stacks. Therefore, the inlet flow rate is an important factor for transient performance of a SOFC stack.

A high-performance aluminum-feed microfluidic fuel cell stack

NASA Astrophysics Data System (ADS)

Wang, Yifei; Leung, Dennis Y. C.

2016-12-01

In this paper, a six-cell microfluidic fuel cell (MFC) stack is demonstrated. Low-cost aluminum is fed directly to the stack, which produces hydrogen fuel on site, through the Al-H2O reaction. This design is not only cost-efficient, but also eliminates the need for hydrogen storage. Unlike the conventional MFC stacks which generally require complex electrolyte distribution and management, the present Al-feed MFC stack requires only a single electrolyte stream, flowing successively through individual cells, which is finally utilized for hydrogen generation. In this manner, the whole system is greatly simplified while the operational robustness is also improved. With 2 M sodium hydroxide solution as electrolyte and kitchen foil Al as fuel, the present six-cell stack (in series) exhibits an open circuit voltage of nearly 6 V and a peak power density of 180.6 mWcm-2 at room temperature. In addition, an energy density of 1 Whg-1(Al) is achieved, which is quite high and comparable with its proton exchange membrane-based counterparts. Finally, pumpless operation of the present stack, together with its practical applications are successfully demonstrated, including lightening LED lights, driving an electric fan, and cell phone charging.

Synergistic Anion-(π) n-π Catalysis on π-Stacked Foldamers.

PubMed

Bornhof, Anna-Bea; Bauzá, Antonio; Aster, Alexander; Pupier, Marion; Frontera, Antonio; Vauthey, Eric; Sakai, Naomi; Matile, Stefan

2018-04-11

In this report, we demonstrate that synergistic effects between π-π stacking and anion-π interactions in π-stacked foldamers provide access to unprecedented catalytic activity. To elaborate on anion-(π) n -π catalysis, we have designed, synthesized and evaluated a series of novel covalent oligomers with up to four face-to-face stacked naphthalenediimides (NDIs). NMR analysis including DOSY confirms folding into π stacks, cyclic voltammetry, steady-state and transient absorption spectroscopy the electronic communication within the π stacks. Catalytic activity, assessed by chemoselective catalysis of the intrinsically disfavored but biologically relevant addition reaction of malonate half thioesters to enolate acceptors, increases linearly with the length of the stacks to reach values that are otherwise beyond reach. This linear increase violates the sublinear power laws of oligomer chemistry. The comparison of catalytic activity with ratiometric changes in absorption and decreasing energy of the LUMO thus results in superlinearity, that is synergistic amplification of anion-π catalysis by remote control over the entire stack. In computational models, increasing length of the π-stacked foldamers correlates sublinearly with changes in surface potentials, chloride binding energies, and the distances between chloride and π surface and within the π stack. Computational evidence is presented that the selective acceleration of disfavored but relevant enolate chemistry by anion-π catalysis indeed originates from the discrimination of planar and bent tautomers with delocalized and localized charges, respectively, on π-acidic surfaces. Computed binding energies of keto and enol intermediates of the addition reaction as well as their difference increase with increasing length of the π stack and thus reflect experimental trends correctly. These results demonstrate that anion-(π) n -π interactions exist and matter, ready for use as a unique new tool in catalysis

Large volume sample stacking of positively chargeable analytes in capillary zone electrophoresis without polarity switching: use of low reversed electroosmotic flow induced by a cationic surfactant at acidic pH.

PubMed

Quirino, J P; Terabe, S

2000-01-01

A simple and effective way to improve detection sensitivity of positively chargeable analytes in capillary zone electrophoresis more than 100-fold is described. Cationic species were made to migrate toward the cathode even under reversed electroosmotic flow caused by a cationic surfactant by using a low pH run buffer. For the first time, with such a configuration, large volume sample stacking of cationic analytes is achieved without a polarity-switching step and loss of efficiency. Samples are prepared in water or aqueous acetonitrile. Aromatic amines and a variety of drugs were concentrated using background solutions containing phosphoric acid and cetyltrimethylammonium bromide. Qualitative and quantitative aspects are also investigated.

Automated manufacturing process for DEAP stack-actuators

NASA Astrophysics Data System (ADS)

Tepel, Dominik; Hoffstadt, Thorben; Maas, Jürgen

2014-03-01

Dielectric elastomers (DE) are thin polymer films belonging to the class of electroactive polymers (EAP), which are coated with compliant and conductive electrodes on each side. Due to the influence of an electrical field, dielectric elastomers perform a large amount of deformation. In this contribution a manufacturing process of automated fabricated stack-actuators based on dielectric electroactive polymers (DEAP) are presented. First of all the specific design of the considered stack-actuator is explained and afterwards the development, construction and realization of an automated manufacturing process is presented in detail. By applying this automated process, stack-actuators with reproducible and homogeneous properties can be manufactured. Finally, first DEAP actuator modules fabricated by the mentioned process are validated experimentally.

Optimization of hole generation in Ti/CFRP stacks

NASA Astrophysics Data System (ADS)

Ivanov, Y. N.; Pashkov, A. E.; Chashhin, N. S.

2018-03-01

The article aims to describe methods for improving the surface quality and hole accuracy in Ti/CFRP stacks by optimizing cutting methods and drill geometry. The research is based on the fundamentals of machine building, theory of probability, mathematical statistics, and experiment planning and manufacturing process optimization theories. Statistical processing of experiment data was carried out by means of Statistica 6 and Microsoft Excel 2010. Surface geometry in Ti stacks was analyzed using a Taylor Hobson Form Talysurf i200 Series Profilometer, and in CFRP stacks - using a Bruker ContourGT-Kl Optical Microscope. Hole shapes and sizes were analyzed using a Carl Zeiss CONTURA G2 Measuring machine, temperatures in cutting zones were recorded with a FLIR SC7000 Series Infrared Camera. Models of multivariate analysis of variance were developed. They show effects of drilling modes on surface quality and accuracy of holes in Ti/CFRP stacks. The task of multicriteria drilling process optimization was solved. Optimal cutting technologies which improve performance were developed. Methods for assessing thermal tool and material expansion effects on the accuracy of holes in Ti/CFRP/Ti stacks were developed.

Theoretical Evidence for the Stronger Ability of Thymine to Disperse SWCNT than Cytosine and Adenine: self-stacking of DNA bases vs their cross-stacking with SWCNT

PubMed Central

Wang, Yixuan

2008-01-01

Self-stacking of four DNA bases, adenine (A), cytosine (C), guanine (G) and thymine (T), and their cross-stacking with (5,5) as well as (10,0) single walled carbon nanotubes (SWCNTs) were extensively investigated with a novel hybrid DFT method, MPWB1K/cc-pVDZ. The binding energies were further corrected with MP2/6-311++G(d,p) method in both gas phase and aqueous solution, where the solvent effects were included with conductor-like polarized continuum model (CPCM) model and UAHF radii. The strongest self-stacking of G and A takes displaced anti-parallel configuration, but un-displaced or “eclipsed” anti-parallel configuration is the most stable for C and T. In gas phase the self-stacking of nucleobases decreases in the sequence G>A>C>T, while because of quite different solvent effects their self-stacking in aqueous solution exhibits a distinct sequence A>G>T>C. For a given base, cross-stacking is stronger than self-stacking in both gas phase and aqueous solution. Binding energy for cross-stacking in gas phase varies as G>A>T>C for both (10,0) and (5,5) SWCNTs, and the binding of four nucleobases to (10,0) is slightly stronger than to (5,5) SWCNT by a range of 0.1–0.5 kcal/mol. The cross-stacking in aqueous solution varies differently from that gas phase: A>G>T>C for (10,0) SWCNT and G>A>T>C for (5,5) SWCNT. It is suggested that the ability of nucleobases to disperse SWCNT depends on relative strength (ΔΔEbinsol) of self-stacking and cross-stacking with SWCNT in aqueous solution. Of the four investigated nucleobases thymine (T) exhibits the highest (ΔΔEbinsol) which can well explain the experimental finding that T more efficiently functionalizes SWCNT than C and A. PMID:18946514

A Reference Stack for PHM Architectures

DTIC Science & Technology

2014-10-02

components, fault modes and prognostics such as that described by MIMOSA (2009) and ISO 13374-3:2012 (2012). Section 2.6 described a semantic...architecture, and the use of a SOA is further discussed in Section 3.3.2. MIMOSA is a stack-oriented data architecture. Figure 11 shows its stack of...format (US Army PEWG, 2011). The tagging in ABCD format respects the data layers that are found in the MIMOSA standard ( MIMOSA , 2009) and in ISO

Fabrication of high gradient insulators by stack compression

DOEpatents

Harris, John Richardson; Sanders, Dave; Hawkins, Steven Anthony; Norona, Marcelo

2014-04-29

Individual layers of a high gradient insulator (HGI) are first pre-cut to their final dimensions. The pre-cut layers are then stacked to form an assembly that is subsequently pressed into an HGI unit with the desired dimension. The individual layers are stacked, and alignment is maintained, using a sacrificial alignment tube that is removed after the stack is hot pressed. The HGI's are used as high voltage vacuum insulators in energy storage and transmission structures or devices, e.g. in particle accelerators and pulsed power systems.

Domain wall pinning on strain relaxation defects (stacking faults) in nanoscale FePd (001)/MgO thin films

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

Hsiao, C. H.; Ouyang, Chuenhou, E-mail: wei0208@gmail.com, E-mail: houyang@mx.nthu.edu.tw; Yao, Y. D.

FePd (001) films, prepared by an electron beam deposition system on MgO(100), exhibit a perpendicular magnetic anisotropy (1.7 × 10{sup 7 }erg/cc) with a high order parameter (0.92). The relation between stacking faults induced by the strain relaxation, which act as strong domain wall pinning sites, and the perpendicular coercivity of (001) oriented L1{sub 0} FePd films prepared at different temperatures have been investigated. Perpendicular coercivity can be apparently enhanced by raising the stacking fault densities, which can be elevated by climbing dissociation of total dislocation. The increased stacking fault densities (1.22 nm{sup −2}) with large perpendicular coercivity (6000 Oe) are obtained for samples preparedmore » at 650 °C. This present work shows through controlling stacking fault density in FePd film, the coercivity can be manipulated, which can be applied in future magnetic devices.« less

Improvement in the breakdown endurance of high-κ dielectric by utilizing stacking technology and adding sufficient interfacial layer.

PubMed

Pang, Chin-Sheng; Hwu, Jenn-Gwo

2014-01-01

Improvement in the time-zero dielectric breakdown (TZDB) endurance of metal-oxide-semiconductor (MOS) capacitor with stacking structure of Al/HfO2/SiO2/Si is demonstrated in this work. The misalignment of the conduction paths between two stacking layers is believed to be effective to increase the breakdown field of the devices. Meanwhile, the resistance of the dielectric after breakdown for device with stacking structure would be less than that of without stacking structure due to a higher breakdown field and larger breakdown power. In addition, the role of interfacial layer (IL) in the control of the interface trap density (D it) and device reliability is also analyzed. Device with a thicker IL introduces a higher breakdown field and also a lower D it. High-resolution transmission electron microscopy (HRTEM) of the samples with different IL thicknesses is provided to confirm that IL is needed for good interfacial property.

Music preference, depression, suicidal preoccupation, and personality: comment on Stack and Gundlach's papers.

PubMed

Lester, D; Whipple, M

1996-01-01

In a sample of students, preference for country and western music was not associated with depression or suicidal preoccupation as has been suggested by Stack and Gundlach. However, preference for heavy metal music was associated with prior suicidal ideation. Stronger associations were found between music preferences and measures of psychoticism and extraversion.

Full waveform approach for the automatic detection and location of acoustic emissions from hydraulic fracturing at Äspö (Sweden)

NASA Astrophysics Data System (ADS)

Ángel López Comino, José; Cesca, Simone; Heimann, Sebastian; Grigoli, Francesco; Milkereit, Claus; Dahm, Torsten; Zang, Arno

2017-04-01

A crucial issue to analyse the induced seismicity for hydraulic fracturing is the detection and location of massive microseismic or acoustic emissions (AE) activity, with robust and sufficiently accurate automatic algorithms. Waveform stacking and coherence analysis have been tested for local seismic monitoring and mining induced seismicity improving the classical detection and location methods (e.g. short-term-average/long-term-average and automatic picking of the P and S waves first arrivals). These techniques are here applied using a full waveform approach for a hydraulic fracturing experiment (Nova project 54-14-1) that took place 410 m below surface in the Äspö Hard Rock Laboratory (Sweden). Continuous waveform recording with a near field network composed by eleven AE sensors are processed. The piezoelectric sensors have their highest sensitive in the frequency range 1 to 100 kHz, but sampling rates were extended to 1 MHz. We present the results obtained during the conventional, continuous water-injection experiment HF2 (Hydraulic Fracture 2). The event detector is based on the stacking of characteristic functions. It follows a delay-and-stack approach, where the likelihood of the hypocenter location in a pre-selected seismogenic volume is mapped by assessing the coherence of the P onset times at different stations. A low detector threshold is chosen, in order not to loose weaker events. This approach also increases the number of false detections. Therefore, the dataset has been revised manually, and detected events classified in terms of true AE events related to the fracturing process, electronic noise related to 50 Hz overtones, long period and other signals. The location of the AE events is further refined using a more accurate waveform stacking method which uses both P and S phases. A 3D grid is generated around the hydraulic fracturing volume and we retrieve a multidimensional matrix, whose absolute maximum corresponds to the spatial coordinates of the

Online sample concentration and analysis of drugs of abuse in human urine by micelle to solvent stacking in capillary zone electrophoresis.

PubMed

Aturki, Zeineb; Fanali, Salvatore; Rocco, Anna

2016-10-01

A sensitive and rapid CZE-UV method was developed to determine drugs and their metabolites' presence in human urine. Ten drugs of abuse were analyzed including four amphetamines, cocaine, cocaethylene, heroin, morphine, 6-monoacetylmorphine, and 4-methylmethcathinone. An MSS (micelle to solvent stacking) approach was evaluated to enhance method sensitivity. This method considers composition of the micellar sample solution matrix and the injection time. Several analytical conditions influencing the resolution of the drugs mixture as pH and buffer concentration, organic solvent content, were also investigated. The base-line separation of all studied analytes in the same run was achieved within 18 min in an uncoated fused silica capillary (50 μm id × 60 cm) using a background solution containing 50 mM phosphate buffer pH 2.5 and 30% ACN v/v. Other experimental parameters such as applied voltage and capillary temperature were set up at 20 kV and 20°C, respectively. LOD values ranging between 15 and 75 ng/mL for all studied compounds were obtained. From a comparison with conventional CZE, the proposed method provides an increase of sensitivity (39- to 55-fold enhancement factor). Under optimal MSS-CZE conditions, good linearity was achieved (R 2 ≤ 0.9998). The method was finally applied to the analysis of urine samples spiked with a standard mixture after a sample pretreatment, reaching satisfactory recovery values. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Searching for the 3.5 keV Line in the Stacked Suzaku Observations of Galaxy Clusters

NASA Technical Reports Server (NTRS)

Bulbul, Esra; Markevitch, Maxim; Foster, Adam; Miller, Eric; Bautz, Mark; Lowenstein, Mike; Randall, Scott W.; Smith, Randall K.

2016-01-01

We perform a detailed study of the stacked Suzaku observations of 47 galaxy clusters, spanning a redshift range of 0.01-0.45, to search for the unidentified 3.5 keV line. This sample provides an independent test for the previously detected line. We detect a 2sigma-significant spectral feature at 3.5 keV in the spectrum of the full sample. When the sample is divided into two subsamples (cool-core and non-cool core clusters), the cool-core subsample shows no statistically significant positive residuals at the line energy. A very weak (approx. 2sigma confidence) spectral feature at 3.5 keV is permitted by the data from the non-cool-core clusters sample. The upper limit on a neutrino decay mixing angle of sin(sup 2)(2theta) = 6.1 x 10(exp -11) from the full Suzaku sample is consistent with the previous detections in the stacked XMM-Newton sample of galaxy clusters (which had a higher statistical sensitivity to faint lines), M31, and Galactic center, at a 90% confidence level. However, the constraint from the present sample, which does not include the Perseus cluster, is in tension with previously reported line flux observed in the core of the Perseus cluster with XMM-Newton and Suzaku.

Sport stacking activities in school children's motor skill development.

PubMed

Li, Yuhua; Coleman, Diane; Ransdell, Mary; Coleman, Lyndsie; Irwin, Carol

2011-10-01

This study examined the impact of a 12-wk. sport stacking intervention on reaction time (RT), manual dexterity, and hand-eye coordination in elementary school-aged children. 80 Grade 2 students participated in a 15-min. sport stacking practice session every school day for 12 wk., and were tested on psychomotor performance improvement. Tests for choice RT, manual dexterity, and photoelectric rotary pursuit tracking were conducted pre- and post-intervention for both experimental group (n = 36) and the controls (n = 44) who did no sport stacking. Students who had the intervention showed a greater improvement in two-choice RT. No other group difference was found. Such sport stacking activities may facilitate children's central processing and perceptual-motor integration.

Microstructural characterization of high-manganese austenitic steels with different stacking fault energies

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

Sato, Shigeo, E-mail: s.sato@imr.tohoku.ac.jp; Kwon, Eui-Pyo; Imafuku, Muneyuki

Microstructures of tensile-deformed high-manganese austenitic steels exhibiting twinning-induced plasticity were analyzed by electron backscatter diffraction pattern observation and X-ray diffraction measurement to examine the influence of differences in their stacking fault energies on twinning activity during deformation. The steel specimen with the low stacking fault energy of 15 mJ/m{sup 2} had a microstructure with a high population of mechanical twins than the steel specimen with the high stacking fault energy (25 mJ/m{sup 2}). The <111> and <100> fibers developed along the tensile axis, and mechanical twinning occurred preferentially in the <111> fiber. The Schmid factors for slip and twinning deformationsmore » can explain the origin of higher twinning activity in the <111> fiber. However, the high stacking fault energy suppresses the twinning activity even in the <111> fiber. A line profile analysis based on the X-ray diffraction data revealed the relationship between the characteristics of the deformed microstructures and the stacking fault energies of the steel specimens. Although the variation in dislocation density with the tensile deformation is not affected by the stacking fault energies, the effect of the stacking fault energies on the crystallite size refinement becomes significant with a decrease in the stacking fault energies. Moreover, the stacking fault probability, which was estimated from a peak-shift analysis of the 111 and 200 diffractions, was high for the specimen with low stacking fault energy. Regardless of the difference in the stacking fault energies of the steel specimens, the refined crystallite size has a certain correlation with the stacking fault probability, indicating that whether the deformation-induced crystallite-size refinement occurs depends directly on the stacking fault probability rather than on the stacking fault energies in the present steel specimens. - Highlights: {yields} We studied effects of stacking fault

Simultaneous stack-gas scrubbing and waste water treatment

NASA Technical Reports Server (NTRS)

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

1980-01-01

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.

Scale dependant compensational stacking of channelized sedimentary deposits

NASA Astrophysics Data System (ADS)

Wang, Y.; Straub, K. M.; Hajek, E. A.

2010-12-01

Compensational stacking, the tendency for sediment transport system to preferentially fill topographic lows, thus smoothing out topographic relief is a concept used in the interpretation of the stratigraphic record. Recently, a metric was developed to quantify the strength of compensation in sedimentary basins by comparing observed stacking patterns to what would be expected from simple, uncorrelated stacking. This method uses the rate of decay of spatial variability in sedimentation between picked depositional horizons with increasing vertical stratigraphic averaging distance. We explore how this metric varies as a function of stratigraphic scale using data from physical experiments, stratigraphy exposed in outcrops and numerical models. In an experiment conducted at Tulane University’s Sediment Dynamics Laboratory, the topography of a channelized delta formed by weakly cohesive sediment was monitored along flow-perpendicular transects at a high temporal resolution relative to channel kinematics. Over the course of this experiment a uniform relative subsidence pattern, designed to isolate autogenic processes, resulted in the construction of a stratigraphic package that is 25 times as thick as the depth of the experimental channels. We observe a scale-dependence on the compensational stacking of deposits set by the system’s avulsion time-scale. Above the avulsion time-scale deposits stack purely compensationally, but below this time-scale deposits stack somewhere between randomly and deterministically. The well-exposed Ferris Formation (Cretaceous/Paleogene, Hanna Basin, Wyoming, USA) also shows scale-dependant stratigraphic organization which appears to be set by an avulsion time-scale. Finally, we utilize simple object-based models to illustrate how channel avulsions influence compensation in alluvial basins.

Radiation Tolerant Intelligent Memory Stack (RTIMS)

NASA Technical Reports Server (NTRS)

Ng, Tak-kwong; Herath, Jeffrey A.

2006-01-01

The Radiation Tolerant Intelligent Memory Stack (RTIMS), suitable for both geostationary and low earth orbit missions, has been developed. The memory module is fully functional and undergoing environmental and radiation characterization. A self-contained flight-like module is expected to be completed in 2006. RTIMS provides reconfigurable circuitry and 2 gigabits of error corrected or 1 gigabit of triple redundant digital memory in a small package. RTIMS utilizes 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 circuitries are stacked into a module of 42.7mm x 42.7mm x 13.00mm. Triple module redundancy, current limiting, configuration scrubbing, and single event function interrupt detection are employed to mitigate radiation effects. The mitigation techniques significantly simplify system design. RTIMS is well suited for deployment in real-time data processing, reconfigurable computing, and memory intensive applications.

Computer Center: 2 HyperCard Stacks for Biology.

ERIC Educational Resources Information Center

Duhrkopf, Richard, Ed.

1989-01-01

Two Hypercard stacks are reviewed including "Amino Acids," created to help students associate amino acid names with their structures, and "DNA Teacher," a tutorial on the structure and function of DNA. Availability, functions, hardware requirements, and general comments on these stacks are provided. (CW)

Electrolytic cell stack with molten electrolyte migration control

DOEpatents

Kunz, H. Russell; Guthrie, Robin J.; Katz, Murray

1988-08-02

An electrolytic cell stack includes inactive electrolyte reservoirs at the upper and lower end portions thereof. The reservoirs are separated from the stack of the complete cells by impermeable, electrically conductive separators. Reservoirs at the negative end are initially low in electrolyte and the reservoirs at the positive end are high in electrolyte fill. During stack operation electrolyte migration from the positive to the negative end will be offset by the inactive reservoir capacity. In combination with the inactive reservoirs, a sealing member of high porosity and low electrolyte retention is employed to limit the electrolyte migration rate.

Electrolytic cell stack with molten electrolyte migration control

DOEpatents

Kunz, H.R.; Guthrie, R.J.; Katz, M.

1987-03-17

An electrolytic cell stack includes inactive electrolyte reservoirs at the upper and lower end portions thereof. The reservoirs are separated from the stack of the complete cells by impermeable, electrically conductive separators. Reservoirs at the negative end are initially low in electrolyte and the reservoirs at the positive end are high in electrolyte fill. During stack operation electrolyte migration from the positive to the negative end will be offset by the inactive reservoir capacity. In combination with the inactive reservoirs, a sealing member of high porosity and low electrolyte retention is employed to limit the electrolyte migration rate. 5 figs.

Remote fire stack igniter. [with solenoid-controlled valve

NASA Technical Reports Server (NTRS)

Ray, W. L. (Inventor)

1974-01-01

An igniter is described mounted on a vent stack with an upper, flame cage near the top of the stack to ignite emissions from the stack. The igniter is a tube with a lower, open, flared end having a spark plug near the lower end and a solenoid-controlled valve which supplies propane fuel from a supply tank. Propane from the tank is supplied at the top under control of a second, solenoid-controlled valve. The valve controlling the lower supply is closed after ignition at the flame cage. The igniter is economical, practical, and highly reliable.

Optoelectronic interconnects for 3D wafer stacks

NASA Astrophysics Data System (ADS)

Ludwig, David E.; Carson, John C.; Lome, Louis S.

1996-01-01

Wafer and chip stacking are envisioned as a means of providing increased processing power within the small confines of a three-dimensional structure. Optoelectronic devices can play an important role in these dense 3-D processing electronic packages in two ways. In pure electronic processing, optoelectronics can provide a method for increasing the number of input/output communication channels within the layers of the 3-D chip stack. Non-free space communication links allow the density of highly parallel input/output ports to increase dramatically over typical edge bus connections. In hybrid processors, where electronics and optics play a role in defining the computational algorithm, free space communication links are typically utilized for, among other reasons, the increased network link complexity which can be achieved. Free space optical interconnections provide bandwidths and interconnection complexity unobtainable in pure electrical interconnections. Stacked 3-D architectures can provide the electronics real estate and structure to deal with the increased bandwidth and global information provided by free space optical communications. This paper provides definitions and examples of 3-D stacked architectures in optoelectronics processors. The benefits and issues of these technologies are discussed.

Optoelectronic interconnects for 3D wafer stacks

NASA Astrophysics Data System (ADS)

Ludwig, David; Carson, John C.; Lome, Louis S.

1996-01-01

Wafer and chip stacking are envisioned as means of providing increased processing power within the small confines of a three-dimensional structure. Optoelectronic devices can play an important role in these dense 3-D processing electronic packages in two ways. In pure electronic processing, optoelectronics can provide a method for increasing the number of input/output communication channels within the layers of the 3-D chip stack. Non-free space communication links allow the density of highly parallel input/output ports to increase dramatically over typical edge bus connections. In hybrid processors, where electronics and optics play a role in defining the computational algorithm, free space communication links are typically utilized for, among other reasons, the increased network link complexity which can be achieved. Free space optical interconnections provide bandwidths and interconnection complexity unobtainable in pure electrical interconnections. Stacked 3-D architectures can provide the electronics real estate and structure to deal with the increased bandwidth and global information provided by free space optical communications. This paper will provide definitions and examples of 3-D stacked architectures in optoelectronics processors. The benefits and issues of these technologies will be discussed.

Deformation induced microtwins and stacking faults in aluminum single crystal.

PubMed

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

2008-09-12

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.

Reliability analysis and initial requirements for FC systems and stacks

NASA Astrophysics Data System (ADS)

Åström, K.; Fontell, E.; Virtanen, S.

In the year 2000 Wärtsilä Corporation started an R&D program to develop SOFC systems for CHP applications. The program aims to bring to the market highly efficient, clean and cost competitive fuel cell systems with rated power output in the range of 50-250 kW for distributed generation and marine applications. In the program Wärtsilä focuses on system integration and development. System reliability and availability are key issues determining the competitiveness of the SOFC technology. In Wärtsilä, methods have been implemented for analysing the system in respect to reliability and safety as well as for defining reliability requirements for system components. A fault tree representation is used as the basis for reliability prediction analysis. A dynamic simulation technique has been developed to allow for non-static properties in the fault tree logic modelling. Special emphasis has been placed on reliability analysis of the fuel cell stacks in the system. A method for assessing reliability and critical failure predictability requirements for fuel cell stacks in a system consisting of several stacks has been developed. The method is based on a qualitative model of the stack configuration where each stack can be in a functional, partially failed or critically failed state, each of the states having different failure rates and effects on the system behaviour. The main purpose of the method is to understand the effect of stack reliability, critical failure predictability and operating strategy on the system reliability and availability. An example configuration, consisting of 5 × 5 stacks (series of 5 sets of 5 parallel stacks) is analysed in respect to stack reliability requirements as a function of predictability of critical failures and Weibull shape factor of failure rate distributions.

Use of space-filling curves to select sample locations in natural resource monitoring studies

Treesearch

Andrew Lister; Charles T. Scott

2009-01-01

The establishment of several large area monitoring networks over the past few decades has led to increased research into ways to spatially balance sample locations across the landscape. Many of these methods are well documented and have been used in the past with great success. In this paper, we present a method using geographic information systems (GIS) and fractals...

Stacking Nematic Elastomers for Artificial Muscle Applications

DTIC Science & Technology

2006-04-01

nematic to isotropic phase transition. In this eport, a new approach is introduced by layering liquid crystal elastomer films to create thermally...actuated stacks. A heating element and thermally onductive grease embedded between elastomer films provide a means for rapid internal heat application...voltage application, stacks composed f two 100 m-thick films and a single heating element produce 18% strain between contracted and relaxed states. In

PRECISION COSMOGRAPHY WITH STACKED VOIDS

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

Lavaux, Guilhem; Wandelt, Benjamin D.

2012-08-01

We present a purely geometrical method for probing the expansion history of the universe from the observation of the shape of stacked voids in spectroscopic redshift surveys. Our method is an Alcock-Paczynski (AP) test based on the average sphericity of voids posited on the local isotropy of the universe. It works by comparing the temporal extent of cosmic voids along the line of sight with their angular, spatial extent. We describe the algorithm that we use to detect and stack voids in redshift shells on the light cone and test it on mock light cones produced from N-body simulations. Wemore » establish a robust statistical model for estimating the average stretching of voids in redshift space and quantify the contamination by peculiar velocities. Finally, assuming that the void statistics that we derive from N-body simulations is preserved when considering galaxy surveys, we assess the capability of this approach to constrain dark energy parameters. We report this assessment in terms of the figure of merit (FoM) of the dark energy task force and in particular of the proposed Euclid mission which is particularly suited for this technique since it is a spectroscopic survey. The FoM due to stacked voids from the Euclid wide survey may double that of all other dark energy probes derived from Euclid data alone (combined with Planck priors). In particular, voids seem to outperform baryon acoustic oscillations by an order of magnitude. This result is consistent with simple estimates based on mode counting. The AP test based on stacked voids may be a significant addition to the portfolio of major dark energy probes and its potentialities must be studied in detail.« less

Air-Cooled Stack Freeze Tolerance Freeze Failure Modes and Freeze Tolerance Strategies for GenDriveTM Material Handling Application Systems and Stacks Final Scientific Report

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

Hancock, David, W.

2012-02-14

Air-cooled stack technology offers the potential for a simpler system architecture (versus liquid-cooled) for applications below 4 kilowatts. The combined cooling and cathode air allows for a reduction in part count and hence a lower cost solution. However, efficient heat rejection challenges escalate as power and ambient temperature increase. For applications in ambient temperatures below freezing, the air-cooled approach has additional challenges associated with not overcooling the fuel cell stack. The focus of this project was freeze tolerance while maintaining all other stack and system requirements. Through this project, Plug Power advanced the state of the art in technology formore » air-cooled PEM fuel cell stacks and related GenDrive material handling application fuel cell systems. This was accomplished through a collaborative work plan to improve freeze tolerance and mitigate freeze-thaw effect failure modes within innovative material handling equipment fuel cell systems designed for use in freezer forklift applications. Freeze tolerance remains an area where additional research and understanding can help fuel cells to become commercially viable. This project evaluated both stack level and system level solutions to improve fuel cell stack freeze tolerance. At this time, the most cost effective solutions are at the system level. The freeze mitigation strategies developed over the course of this project could be used to drive fuel cell commercialization. The fuel cell system studied in this project was Plug Power's commercially available GenDrive platform providing battery replacement for equipment in the material handling industry. The fuel cell stacks were Ballard's commercially available FCvelocity 9SSL (9SSL) liquid-cooled PEM fuel cell stack and FCvelocity 1020ACS (Mk1020) air-cooled PEM fuel cell stack.« less

Fuel cell stack monitoring and system control

DOEpatents

Keskula, Donald H.; Doan, Tien M.; Clingerman, Bruce J.

2005-01-25

A control method for monitoring a fuel cell stack in a fuel cell system in which the actual voltage and actual current from the fuel cell stack are monitored. A preestablished relationship between voltage and current over the operating range of the fuel cell is established. A variance value between the actual measured voltage and the expected voltage magnitude for a given actual measured current is calculated and compared with a predetermined allowable variance. An output is generated if the calculated variance value exceeds the predetermined variance. The predetermined voltage-current for the fuel cell is symbolized as a polarization curve at given operating conditions of the fuel cell. Other polarization curves may be generated and used for fuel cell stack monitoring based on different operating pressures, temperatures, hydrogen quantities.

Transformation diffusion reconstruction of three-dimensional histology volumes from two-dimensional image stacks.

PubMed

Casero, Ramón; Siedlecka, Urszula; Jones, Elizabeth S; Gruscheski, Lena; Gibb, Matthew; Schneider, Jürgen E; Kohl, Peter; Grau, Vicente

2017-05-01

Traditional histology is the gold standard for tissue studies, but it is intrinsically reliant on two-dimensional (2D) images. Study of volumetric tissue samples such as whole hearts produces a stack of misaligned and distorted 2D images that need to be reconstructed to recover a congruent volume with the original sample's shape. In this paper, we develop a mathematical framework called Transformation Diffusion (TD) for stack alignment refinement as a solution to the heat diffusion equation. This general framework does not require contour segmentation, is independent of the registration method used, and is trivially parallelizable. After the first stack sweep, we also replace registration operations by operations in the space of transformations, several orders of magnitude faster and less memory-consuming. Implementing TD with operations in the space of transformations produces our Transformation Diffusion Reconstruction (TDR) algorithm, applicable to general transformations that are closed under inversion and composition. In particular, we provide formulas for translation and affine transformations. We also propose an Approximated TDR (ATDR) algorithm that extends the same principles to tensor-product B-spline transformations. Using TDR and ATDR, we reconstruct a full mouse heart at pixel size 0.92µm×0.92µm, cut 10µm thick, spaced 20µm (84G). Our algorithms employ only local information from transformations between neighboring slices, but the TD framework allows theoretical analysis of the refinement as applying a global Gaussian low-pass filter to the unknown stack misalignments. We also show that reconstruction without an external reference produces large shape artifacts in a cardiac specimen while still optimizing slice-to-slice alignment. To overcome this problem, we use a pre-cutting blockface imaging process previously developed by our group that takes advantage of Brewster's angle and a polarizer to capture the outline of only the topmost layer of wax

Improved Durability of SOEC Stacks for High Temperature Electrolysis

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

James E. O'Brien; Robert C. O'Brien; Xiaoyu Zhang

2013-01-01

High temperature steam electrolysis is a promising technology for efficient and sustainable large-scale hydrogen production. Solid oxide electrolysis cells (SOECs) are able to utilize high temperature heat and electric power from advanced high-temperature nuclear reactors or renewable sources to generate carbon-free hydrogen at large scale. However, long term durability of SOECs needs to be improved significantly before commercialization of this technology can be realized. A degradation rate of 1%/khr or lower is proposed as a threshold value for commercialization of this technology. Solid oxide electrolysis stack tests have been conducted at Idaho National Laboratory to demonstrate recent improvements in long-termmore » durability of SOECs. Electrolyte-supported and electrode-supported SOEC stacks were provided by Ceramatec Inc. and Materials and Systems Research Inc. (MSRI), respectively, for these tests. Long-term durability tests were generally operated for a duration of 1000 hours or more. Stack tests based on technologies developed at Ceramatec and MSRI have shown significant improvement in durability in the electrolysis mode. Long-term degradation rates of 3.2%/khr and 4.6%/khr were observed for MSRI and Ceramatec stacks, espectively. One recent Ceramatec stack even showed negative degradation (performance improvement) over 1900 hours of operation. Optimization of electrode materials, interconnect coatings, and electrolyte-electrode interface microstructures contribute to better durability of SOEC stacks.« less

40 CFR 141.703 - Sampling locations.

Code of Federal Regulations, 2014 CFR

2014-07-01

... the analysis of the sample. (c) Systems that recycle filter backwash water must collect source water samples prior to the point of filter backwash water addition. (d) Bank filtration. (1) Systems that... 141.703 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) WATER PROGRAMS...

40 CFR 141.703 - Sampling locations.

Code of Federal Regulations, 2012 CFR

2012-07-01

... the analysis of the sample. (c) Systems that recycle filter backwash water must collect source water samples prior to the point of filter backwash water addition. (d) Bank filtration. (1) Systems that... 141.703 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) WATER PROGRAMS...

40 CFR 141.703 - Sampling locations.

Code of Federal Regulations, 2013 CFR

2013-07-01

... the analysis of the sample. (c) Systems that recycle filter backwash water must collect source water samples prior to the point of filter backwash water addition. (d) Bank filtration. (1) Systems that... 141.703 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) WATER PROGRAMS...

Computer Simulations to Study Diffraction Effects of Stacking Faults in Beta-SiC: II. Experimental Verification. 2; Experimental Verification

NASA Technical Reports Server (NTRS)

Pujar, Vijay V.; Cawley, James D.; Levine, S. (Technical Monitor)

2000-01-01

Earlier results from computer simulation studies suggest a correlation between the spatial distribution of stacking errors in the Beta-SiC structure and features observed in X-ray diffraction patterns of the material. Reported here are experimental results obtained from two types of nominally Beta-SiC specimens, which yield distinct XRD data. These samples were analyzed using high resolution transmission electron microscopy (HRTEM) and the stacking error distribution was directly determined. The HRTEM results compare well to those deduced by matching the XRD data with simulated spectra, confirming the hypothesis that the XRD data is indicative not only of the presence and density of stacking errors, but also that it can yield information regarding their distribution. In addition, the stacking error population in both specimens is related to their synthesis conditions and it appears that it is similar to the relation developed by others to explain the formation of the corresponding polytypes.

Nonlinearly stacked low noise turbofan stator

NASA Technical Reports Server (NTRS)

Schuster, William B. (Inventor); Nolcheff, Nick A. (Inventor); Gunaraj, John A. (Inventor); Kontos, Karen B. (Inventor); Weir, Donald S. (Inventor)

2009-01-01

A nonlinearly stacked low noise turbofan stator vane having a characteristic curve that is characterized by a nonlinear sweep and a nonlinear lean is provided. The stator is in an axial fan or compressor turbomachinery stage that is comprised of a collection of vanes whose highly three-dimensional shape is selected to reduce rotor-stator and rotor-strut interaction noise while maintaining the aerodynamic and mechanical performance of the vane. The nonlinearly stacked low noise turbofan stator vane reduces noise associated with the fan stage of turbomachinery to improve environmental compatibility.

40 CFR 60.1775 - What types of stack tests must I conduct?

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 6 2011-07-01 2011-07-01 false What types of stack tests must I...-Stack Testing § 60.1775 What types of stack tests must I conduct? Conduct initial and annual stack tests to measure the emission levels of dioxins/furans, cadmium, lead, mercury, particulate matter, opacity...

40 CFR 60.1775 - What types of stack tests must I conduct?

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 6 2010-07-01 2010-07-01 false What types of stack tests must I...-Stack Testing § 60.1775 What types of stack tests must I conduct? Conduct initial and annual stack tests to measure the emission levels of dioxins/furans, cadmium, lead, mercury, particulate matter, opacity...

Developments in Sampling and Analysis Instrumentation for Stationary Sources

ERIC Educational Resources Information Center

Nader, John S.

1973-01-01

Instrumentation for the measurement of pollutant emissions is considered including sample-site selection, sample transport, sample treatment, sample analysis, and data reduction, display, and interpretation. Measurement approaches discussed involve sample extraction from within the stack and electro-optical methods. (BL)

Cup Stacking: Does It Deserve a Place in Physical Education Curricula?

ERIC Educational Resources Information Center

Udermann, Brian E.; Murray, Steven R.

2006-01-01

Cup stacking has become commonplace in today's physical education nomenclature. Proponents make claims that cup stacking improves cognitive, affective, and psychomotor abilities. At physical education conferences, scores of professional physical educators eagerly watch cup stacking representatives construct and deconstruct a variety of pyramids…

Modeling of mechanical properties of stack actuators based on electroactive polymers

NASA Astrophysics Data System (ADS)

Tepel, Dominik; Graf, Christian; Maas, Jürgen

2013-04-01

Dielectric elastomers are thin polymer films belonging to the class of electroactive polymers, which are coated with compliant and conductive electrodes on each side. Under the influence of an electrical field, dielectric elastomers perform a large amount of deformation. Depending on the mechanical setup, stack and roll actuators can be realized. In this contribution the mechanical properties of stack actuators are modeled by a holistic electromechanical approach of a single actuator film, by which the model of a stack actuator without constraints can be derived. Due to the mechanical connection between the stack actuator and the application, bulges occur at the free surfaces of the EAP material, which are calculated, experimentally validated and considered in the model of the stack actuator. Finally, the analytic actuator film model as well as the stack actuator model are validated by comparison to numerical FEM-models in ANSYS.

Analytical results and sample locations of reanalyzed NURE stream-sediment and soil samples for the Humboldt River basin mineral-environmental assessment, northern Nevada

USGS Publications Warehouse

Folger, H. W.

2000-01-01

The U.S. Geological Survey (USGS), in cooperation with the Bureau of Land Management (BLM), began a study in 1996 to describe to the geochemistry of the Humboldt River Basin. The principal sample media evaluated are stream-sediment and soil samples retrieved from the National Uranium Resource Evaluation (NURE) archives located in Denver, Colorado. Samples were retrieved from the Wells, McDermitt, Vya, Lovelock, Winnemucca, Elko, Ely, Millett, Reno, and Tonopah 1? x 2? quadrangles in northern Nevada. The data are appropriate for large-scale reconnaissance resource evaluations and landscape geochemical-geoenvironmental evaluations. The analytical results are presented in this report.

Note: a 3-stage stacked Blumlein using ceramic for energy storage.

PubMed

Wang, Songsong; Shu, Ting; Yang, Hanwu

2013-02-01

We have developed a novel stacked Blumlein with high compactness by using ceramic for energy storage. The total volume of this stacked Blumlein is only 320 × 100 × 185 mm(3). By triggering 3 spark gaps simultaneously, the developed stacked Blumlein is capable of producing a rectangular pulse with a voltage multiplication. A 32 ns quasi-rectangular pulse of 11.4 kV is measured across a 10 Ω dummy load when the 3-stage stacked Blumlein is DC charged up to 4 kV. The voltage multiplication is about 2.9, and the energy efficiency is about 96%. Simulation results indicate that vacuum or transformer oil is appropriate to be the insulation medium for the stacked Blumlein.

Note: A 3-stage stacked Blumlein using ceramic for energy storage

NASA Astrophysics Data System (ADS)

Wang, Songsong; Shu, Ting; Yang, Hanwu

2013-02-01

We have developed a novel stacked Blumlein with high compactness by using ceramic for energy storage. The total volume of this stacked Blumlein is only 320 × 100 × 185 mm3. By triggering 3 spark gaps simultaneously, the developed stacked Blumlein is capable of producing a rectangular pulse with a voltage multiplication. A 32 ns quasi-rectangular pulse of 11.4 kV is measured across a 10 Ω dummy load when the 3-stage stacked Blumlein is DC charged up to 4 kV. The voltage multiplication is about 2.9, and the energy efficiency is about 96%. Simulation results indicate that vacuum or transformer oil is appropriate to be the insulation medium for the stacked Blumlein.

Formation and Growth of Stacking Fault Tetrahedra in Ni via Vacancy Aggregation Mechanism

DOE PAGES

Aidhy, Dilpuneet S.; Lu, Chenyang; Jin, Ke; ...

2015-12-29

Using molecular dynamics simulations, the formation and growth of stacking fault tetrahedra (SFT) are captured by vacancy cluster diffusion and aggregation mechanisms in Ni. The vacancytetrahedron acts as a nucleation point for SFT formation. Simulations show that perfect SFT can grow to the next size perfect SFT via a vacancy aggregation mechanism. The stopping and range of ions in matter (SRIM) calculations and transmission electron microscopy (TEM) observations reveal that SFT can form farther away from the initial cascade-event locations, indicating the operation of diffusion-based vacancy-aggregation mechanism.

Formation and Growth of Stacking Fault Tetrahedra in Ni via Vacancy Aggregation Mechanism

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

Aidhy, Dilpuneet S.; Lu, Chenyang; Jin, Ke

Using molecular dynamics simulations, the formation and growth of stacking fault tetrahedra (SFT) are captured by vacancy cluster diffusion and aggregation mechanisms in Ni. The vacancytetrahedron acts as a nucleation point for SFT formation. Simulations show that perfect SFT can grow to the next size perfect SFT via a vacancy aggregation mechanism. The stopping and range of ions in matter (SRIM) calculations and transmission electron microscopy (TEM) observations reveal that SFT can form farther away from the initial cascade-event locations, indicating the operation of diffusion-based vacancy-aggregation mechanism.

Partial Section Through Stack, Water Tank, and Privy; Plan ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Partial Section Through Stack, Water Tank, and Privy; Plan - Stack, Privies, & Changing Rooms; Elevation - Central of Georgia Railway, Savannah Repair Shops & Terminal Facilities, Bounded by West Broad, Jones, West Boundary & Hull Streets, Savannah, Chatham County, GA

Cool white light-emitting three stack OLED structures for AMOLED display applications.

PubMed

Springer, Ramon; Kang, Byoung Yeop; Lampande, Raju; Ahn, Dae Hyun; Lenk, Simone; Reineke, Sebastian; Kwon, Jang Hyuk

2016-11-28

This paper demonstrates 2-stack and 3-stack white organic light-emitting diodes (WOLEDs) with fluorescent blue and phosphorescent yellow emissive units. The 2-stack and 3-stack WOLED comprises blue-yellow and blue-blue-yellow (blue-yellow-blue) combinations. The position of the yellow emitter and possible cavity lengths in different stack architectures are theoretically and experimentally investigated to reach Commission Internationale de L'Eclairage (CIE) coordinates of near (0.333/0.333). Here, a maximum external quantum efficiency (EQE) of 23.6% and current efficiency of 62.2 cd/A at 1000 cd/m² as well as suitable CIE color coordinates of (0.335/0.313) for the blue-blue-yellow 3-stack hybrid WOLED structure is reported. In addition, the blue-yellow-blue 3-stack architecture exhibits an improved angular dependence compared to the blue-blue-yellow structure at a decreased EQE of 19.1%.

Gene stacking by recombinases

USDA-ARS?s Scientific Manuscript database

Efficient methods of stacking genes into plant genomes are needed to expedite transfer of multigenic traits into diverse crops grown in a variety of environments. Over two decades of research has identified several site-specific recombinases that carry out efficient cis and trans recombination betw...

40 CFR 141.703 - Sampling locations.

Code of Federal Regulations, 2010 CFR

2010-07-01

... multiple plants draw water from the same influent, such as the same pipe or intake, the State may approve...) The State may approve a system to collect a source water sample after chemical treatment. To grant this approval, the State must determine that collecting a sample prior to chemical treatment is not...

Vibration mode analysis of the proton exchange membrane fuel cell stack

NASA Astrophysics Data System (ADS)

Liu, B.; Liu, L. F.; Wei, M. Y.; Wu, C. W.

2016-11-01

Proton exchange membrane fuel cell (PEMFC) stacks usually undergo vibration during packing, transportation, and serving time, in particular for those used in the automobiles or portable equipment. To study the stack vibration response, based on finite element method (FEM), a mode analysis is carried out in the present paper. Using this method, we can distinguish the local vibration from the stack global modes, predict the vibration responses, such as deformed shape and direction, and discuss the effects of the clamping configuration and the clamping force magnitude on vibration modes. It is found that when the total clamping force remains the same, increasing the bolt number can strengthen the stack resistance to vibration in the clamping direction, but cannot obviously strengthen stack resistance to vibration in the translations perpendicular to clamping direction and the three axis rotations. Increasing the total clamping force can increase both of the stack global mode and the bolt local mode frequencies, but will decrease the gasket local mode frequency.

Ablation of film stacks in solar cell fabrication processes

DOEpatents

Harley, Gabriel; Kim, Taeseok; Cousins, Peter John

2013-04-02

A dielectric film stack of a solar cell is ablated using a laser. The dielectric film stack includes a layer that is absorptive in a wavelength of operation of the laser source. The laser source, which fires laser pulses at a pulse repetition rate, is configured to ablate the film stack to expose an underlying layer of material. The laser source may be configured to fire a burst of two laser pulses or a single temporally asymmetric laser pulse within a single pulse repetition to achieve complete ablation in a single step.

Stacking-dependent electronic property of trilayer graphene epitaxially grown on Ru(0001)

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

Que, Yande; Xiao, Wende, E-mail: wdxiao@iphy.ac.cn, E-mail: hjgao@iphy.ac.cn; Chen, Hui

The growth, atomic structure, and electronic property of trilayer graphene (TLG) on Ru(0001) were studied by low temperature scanning tunneling microscopy and spectroscopy in combined with tight-binding approximation (TBA) calculations. TLG on Ru(0001) shows a flat surface with a hexagonal lattice due to the screening effect of the bottom two layers and the AB-stacking in the top two layers. The coexistence of AA- and AB-stacking in the bottom two layers leads to three different stacking orders of TLG, namely, ABA-, ABC-, and ABB-stacking. STS measurements combined with TBA calculations reveal that the density of states of TLG with ABC- andmore » ABB-stacking is characterized by one and two sharp peaks near to the Fermi level, respectively, in contrast to the V-shaped feature of TLG with ABA-stacking. Our work demonstrates that TLG on Ru(0001) might be an ideal platform for exploring stacking-dependent electronic properties of graphene.« less

Stacking-dependent electronic property of trilayer graphene epitaxially grown on Ru(0001)

NASA Astrophysics Data System (ADS)

Que, Yande; Xiao, Wende; Chen, Hui; Wang, Dongfei; Du, Shixuan; Gao, Hong-Jun

2015-12-01

The growth, atomic structure, and electronic property of trilayer graphene (TLG) on Ru(0001) were studied by low temperature scanning tunneling microscopy and spectroscopy in combined with tight-binding approximation (TBA) calculations. TLG on Ru(0001) shows a flat surface with a hexagonal lattice due to the screening effect of the bottom two layers and the AB-stacking in the top two layers. The coexistence of AA- and AB-stacking in the bottom two layers leads to three different stacking orders of TLG, namely, ABA-, ABC-, and ABB-stacking. STS measurements combined with TBA calculations reveal that the density of states of TLG with ABC- and ABB-stacking is characterized by one and two sharp peaks near to the Fermi level, respectively, in contrast to the V-shaped feature of TLG with ABA-stacking. Our work demonstrates that TLG on Ru(0001) might be an ideal platform for exploring stacking-dependent electronic properties of graphene.

Stacked endoplasmic reticulum sheets are connected by helicoidal membrane motifs

PubMed Central

Terasaki, Mark; Shemesh, Tom; Kasthuri, Narayanan; Klemm, Robin W.; Schalek, Richard; Hayworth, Kenneth J.; Hand, Arthur R.; Yankova, Maya; Huber, Greg; Lichtman, Jeff W.; Rapoport, Tom A.; Kozlov, Michael M.

2013-01-01

The endoplasmic reticulum (ER) often forms stacked membrane sheets, an arrangement that is likely required to accommodate a maximum of membrane-bound polysomes for secretory protein synthesis. How sheets are stacked is unknown. Here, we used novel staining and automated ultra-thin sectioning electron microscopy methods to analyze stacked ER sheets in neuronal cells and secretory salivary gland cells of mice. Our results show that stacked ER sheets form a continuous membrane system in which the sheets are connected by twisted membrane surfaces with helical edges of left- or right-handedness. The three-dimensional structure of tightly stacked ER sheets resembles a parking garage, in which the different levels are connected by helicoidal ramps. A theoretical model explains the experimental observations and indicates that the structure corresponds to a minimum of elastic energy of sheet edges and surfaces. The structure allows the dense packing of ER sheets in the restricted space of a cell. PMID:23870120

Stacked endoplasmic reticulum sheets are connected by helicoidal membrane motifs.

PubMed

Terasaki, Mark; Shemesh, Tom; Kasthuri, Narayanan; Klemm, Robin W; Schalek, Richard; Hayworth, Kenneth J; Hand, Arthur R; Yankova, Maya; Huber, Greg; Lichtman, Jeff W; Rapoport, Tom A; Kozlov, Michael M

2013-07-18

The endoplasmic reticulum (ER) often forms stacked membrane sheets, an arrangement that is likely required to accommodate a maximum of membrane-bound polysomes for secretory protein synthesis. How sheets are stacked is unknown. Here, we used improved staining and automated ultrathin sectioning electron microscopy methods to analyze stacked ER sheets in neuronal cells and secretory salivary gland cells of mice. Our results show that stacked ER sheets form a continuous membrane system in which the sheets are connected by twisted membrane surfaces with helical edges of left- or right-handedness. The three-dimensional structure of tightly stacked ER sheets resembles a parking garage, in which the different levels are connected by helicoidal ramps. A theoretical model explains the experimental observations and indicates that the structure corresponds to a minimum of elastic energy of sheet edges and surfaces. The structure allows the dense packing of ER sheets in the restricted space of a cell. Copyright © 2013 Elsevier Inc. All rights reserved.

The in-phase states of Josephson junctions stacks as attractors

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

Hristov, I.; Dimova, S.; Hristova, R.

2014-11-12

The aim of this investigation is to show that the coherent, in-phase states of intrinsic Josephson junctions stacks are attractors of the stacks' states when the applied external magnetic field h{sub e} and the external current γ vary within certain domains. Mathematically the problem is to find the solutions of the system of perturbed sine-Gordon equations for fixed other parameters and zero or random initial conditions. We determine the region in the plane (h{sub e}, γ), where the in-phase states are attractors of the stack's states for arbitrary initial perturbations. This is important, because the in-phase states are required formore » achieving terahertz radiation from the Josephson stacks.« less

Purex Plant comparison with 40 CFR 61, subpart H, and other referenced guidelines for the Product Removal (PR) (296-A-1) stack

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

Lohrasbi, J.

Dose calculations for atmospheric radionuclide releases from the Hanford Site for calendar year (CY) 1992 were performed by Pacific Northwest Laboratory (PNL) using the approved US Environmental Protection Agency (EPA) CAP-88 computer model. Emissions from discharge points in the Hanford Site 100, 200, 300, 400, and 600 areas were calculated based on results of analyses of continuous and periodic sampling conducted at the discharge points. These calculated emissions were provided for inclusion in the CAP-88 model by area and by individual facility for those facilities having the potential to contribute more than 10 percent of the Hanford Site total ormore » to result in an impact of greater than 0.1 mrem per year to the maximally exposed individual (MEI). Also included in the assessment of offsite dose modeling are the measured radioactive emissions from all Hanford Site stacks that have routine monitoring performed. Record sampling systems have been installed on all stacks and vents that use exhaust fans to discharge air that potentially may carry airborne radioactivity. Estimation of activity from ingrowth of long-lived radioactive progeny is not included in the CAP-88 model; therefore, the Hanford Site GENII code (Napier et al. 1988) was used to supplement the CAP-88 dose calculations. When the dose to the MEI located in the Ringold area was calculated, the effective dose equivalent (EDE) from combined Hanford Site radioactive airborne emissions was shown to be 3.7E-03 mrem. This value was reported in the annual air emission report prepared for the Hanford Site (RL 1993).« less

Supra-Nanoparticle Functional Assemblies through Programmable Stacking.

PubMed

Tian, Cheng; Cordeiro, Marco Aurelio L; Lhermitte, Julien; Xin, Huolin L; Shani, Lior; Liu, Mingzhao; Ma, Chunli; Yeshurun, Yosef; DiMarzio, Donald; Gang, Oleg

2017-07-25

The quest for the by-design assembly of material and devices from nanoscale inorganic components is well recognized. Conventional self-assembly is often limited in its ability to control material morphology and structure simultaneously. Here, we report a general method of assembling nanoparticles in a linear "pillar" morphology with regulated internal configurations. Our approach is inspired by supramolecular systems, where intermolecular stacking guides the assembly process to form diverse linear morphologies. Programmable stacking interactions were realized through incorporation of DNA coded recognition between the designed planar nanoparticle clusters. This resulted in the formation of multilayered pillar architectures with a well-defined internal nanoparticle organization. By controlling the number, position, size, and composition of the nanoparticles in each layer, a broad range of nanoparticle pillars were assembled and characterized in detail. In addition, we demonstrated the utility of this stacking assembly strategy for investigating plasmonic and electrical transport properties.

Measurements of proton energy spectra using a radiochromic film stack

NASA Astrophysics Data System (ADS)

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

2014-10-01

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.

SIMULATIONS OF TRANSVERSE STACKING IN THE NSLS-II BOOSTER

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

Fliller III, R.; Shaftan, T.

2011-03-28

The NSLS-II injection system consists of a 200 MeV linac and a 3 GeV booster. The linac needs to deliver 15 nC in 80 - 150 bunches to the booster every minute to achieve current stability goals in the storage ring. This is a very stringent requirement that has not been demonstrated at an operating light source. We have developed a scheme to transversely stack two bunch trains in the NSLS-II booster in order to alleviate the charge requirements on the linac. This scheme has been outlined previously. In this paper we show particle tracking simulations of the tracking scheme.more » We show simulations of the booster ramp with a stacked beam for a variety of lattice errors and injected beam parameters. In all cases the performance of the proposed stacking method is sufficient to reduce the required charge from the linac. For this reason the injection system of the NSLS-II booster is being designed to include this feature. The NSLS-II injection system consists of a 200 MeV linac and a 3 GeV booster. The injectors must provide 7.5nC in bunch trains 80-150 bunches long every minute for top off operation of the storage ring. Top off then requires that the linac deliver 15nC of charge once losses in the injector chain are taken into consideration. This is a very stringent requirement that has not been demonstrated at an operating light source. For this reason we have developed a method to transversely stack two bunch trains in the booster while maintaining the charge transport efficiency. This stacking scheme has been discussed previously. In this paper we show the simulations of the booster ramp with a single bunch train in the booster. Then we give a brief overview of the stacking scheme. Following, we show the results of stacking two bunch trains in the booster with varying beam emittances and train separations. The behavior of the beam through the ramp is examined showing that it is possible to stack two bunch trains in the booster.« less

Investigation of the characteristics of a stacked direct borohydride fuel cell for portable applications

NASA Astrophysics Data System (ADS)

Kim, Cheolhwan; Kim, Kyu-Jung; Ha, Man Yeong

To investigate the possibility of the portable application of a direct borohydride fuel cell (DBFC), weight reduction of the stack and high stacking of the cells are investigated for practical running conditions. For weight reduction, carbon graphite is adopted as the bipolar plate material even though it has disadvantages in tight stacking, which results in stacking loss from insufficient material strength. For high stacking, it is essential to have a uniform fuel distribution among cells and channels to maintain equal electric load on each cell. In particular, the design of the anode channel is important because active hydrogen generation causes non-uniformity in the fuel flow-field of the cells and channels. To reduce the disadvantages of stacking force margin and fuel maldistribution, an O-ring type-sealing system with an internal manifold and a parallel anode channel design is adopted, and the characteristics of a single and a five-cell fuel cell stack are analyzed. By adopting carbon graphite, the stack weight can be reduced by 4.2 times with 12% of performance degradation from the insufficient stacking force. When cells are stacked, the performance exceeds the single-cell performance because of the stack temperature increase from the reduction of the radiation area from the narrow stacking of cells.

44. VIEW LOOKING EAST, OF WESTINGHOUSELEBLANC JET CONDENSER LOCATED UNDER ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

44. VIEW LOOKING EAST, OF WESTINGHOUSE-LEBLANC JET CONDENSER LOCATED UNDER TURBINE NUMBER 3. THE SPHERICAL HOUSING AT THE TOP RIGHT OF THE PHOTOGRAPH IS A RELIEF VALVE. IN THE EVENTS OF TURBINE OVERPRESSURE THE RELIEF VALVE OPENS AND VENTS EXCESSIVE STEAM PRESSURE TO AN EXHAUST STACK THUS BYPASSING THE CONDENSER. - New York, New Haven & Hartford Railroad, Cos Cob Power Plant, Sound Shore Drive, Greenwich, Fairfield County, CT

40 CFR 60.1290 - How are the stack test data used?

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 6 2011-07-01 2011-07-01 false How are the stack test data used? 60.1290 Section 60.1290 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS... Modification or Reconstruction is Commenced After June 6, 2001 Stack Testing § 60.1290 How are the stack test...

40 CFR 60.1290 - How are the stack test data used?

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 7 2014-07-01 2014-07-01 false How are the stack test data used? 60.1290 Section 60.1290 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS... Modification or Reconstruction is Commenced After June 6, 2001 Stack Testing § 60.1290 How are the stack test...

40 CFR 60.1290 - How are the stack test data used?

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 6 2010-07-01 2010-07-01 false How are the stack test data used? 60.1290 Section 60.1290 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS... Modification or Reconstruction is Commenced After June 6, 2001 Stack Testing § 60.1290 How are the stack test...

40 CFR 60.1290 - How are the stack test data used?

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 7 2012-07-01 2012-07-01 false How are the stack test data used? 60.1290 Section 60.1290 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS... Modification or Reconstruction is Commenced After June 6, 2001 Stack Testing § 60.1290 How are the stack test...

40 CFR 60.1290 - How are the stack test data used?

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 7 2013-07-01 2013-07-01 false How are the stack test data used? 60.1290 Section 60.1290 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS... Modification or Reconstruction is Commenced After June 6, 2001 Stack Testing § 60.1290 How are the stack test...

Alternative actions on the K stack problem

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

Spencer, H.G.

1958-09-29

On June 6, 1958, KW Operations had HCR Channel No. 16 borescoped to determine why this rod could not be inserted on May 3. Observations revealed 3X balls in the channel and horizontal separation between graphite blocks ranging from 1/2 inch to 2 1/4 inch. The separations were noted only in the first fifteen feet in from the outer skin and in the last five feet of the channel. As a result of these findings and past operational difficulties with certain HCR`s at both KE and KW Reactors, a program of measurements is in progress to determine the extent andmore » causes of the stack displacements. From measurements and observations so far obtained, the following conclusions may be drawn about separations at locations of consequence to the loss of 3X balls from channels: Side to side horizontal separations totaling two to three inches have been observed at both reactors. The significant separations lie outside of the VSR pattern and in the lower half of the stack. The VSR pattern does not include the six outer ball 3X channels. There are probably a few small separations (< 1/2 inch) at the outer VSR`s. There are probably no separations large enough to admit balls on inner VSR channels, i.e. VSR`s inside the outer front to rear rows of VSR`s. These conclusions can not be considered fully reliable, but no information obtained to date refutes them. A team was established on 9-17-58 to evaluate and provide information on alternate courses of action for elimination or alleviation of the problem. This report contains the information and recommendations developed by the team.« less

Polycyclic aromatic hydrocarbon (PAH)-containing soils from coal gangue stacking areas contribute to epithelial to mesenchymal transition (EMT) modulation on cancer cell metastasis.

PubMed

Yun, Yang; Gao, Rui; Yue, Huifeng; Liu, Xiaofang; Li, Guangke; Sang, Nan

2017-02-15

The total accumulative stockpiles of gangue in China comprise 4.5billion metric tons, and approximately 659million tons of additional gangue are generated per year. Considering the stacking characteristics are highly heterogeneous, the potential cancer risks from the presence of polycyclic aromatic hydrocarbons (PAHs) remain elusive. This study aimed to determine whether PAH-containing soil around coal gangue stacking areas poses a potential cancer risk and contributes to cancer cell metastasis. The results indicate that eighteen PAHs, primarily originated from coal gangue, exhibited distance variations from the coal gangues to the downstream villages, and the abandoned colliery posed increased potential carcinogenic risks for humans as a result of long-term stacking of coal gangue. Furthermore, soil samples stimulated HepG2 cell migration and invasion in a PAH-dependent manner, and the action was involved in PPARγ-mediated epithelial to mesenchymal transition (EMT) modulation. These findings highlight the potential cancer risk of PAH-containing soil samples around coal gangue stacking areas, and identify important biomarkers underlying the risk and targets preventing the outcomes in polluted areas. Copyright © 2016 Elsevier B.V. All rights reserved.

Control of electrolyte fill to fuel cell stack

DOEpatents

Pollack, William

1982-01-01

A fuel cell stack which can be operated with cells in a horizontal position so that the fuel cell stack does not have to be taken out of operation when adding an electrolyte such as an acid. Acid is supplied to each matrix in a stack of fuel cells at a uniform, low pressure so that the matrix can either be filled initially or replenished with acid lost in operation of the cell, without exceeding the bubble pressure of the matrix or the flooding pressure of the electrodes on either side of the matrix. Acid control to each cell is achieved by restricting and offsetting the opening of electrolyte fill holes in the matrix relative to openings in the plates which sandwich the matrix and electrodes therebetween.

Porous Structures in Stacked, Crumpled and Pillared Graphene-Based 3D Materials.

PubMed

Guo, Fei; Creighton, Megan; Chen, Yantao; Hurt, Robert; Külaots, Indrek

2014-01-01

Graphene, an atomically thin material with the theoretical surface area of 2600 m 2 g -1 , has great potential in the fields of catalysis, separation, and gas storage if properly assembled into functional 3D materials at large scale. In ideal non-interacting ensembles of non-porous multilayer graphene plates, the surface area can be adequately estimated using the simple geometric law ~ 2600 m 2 g -1 /N, where N is the number of graphene sheets per plate. Some processing operations, however, lead to secondary plate-plate stacking, folding, crumpling or pillaring, which give rise to more complex structures. Here we show that bulk samples of multilayer graphene plates stack in an irregular fashion that preserves the 2600/N surface area and creates regular slot-like pores with sizes that are multiples of the unit plate thickness. In contrast, graphene oxide deposits into films with massive area loss (2600 to 40 m 2 g -1 ) due to nearly perfect alignment and stacking during the drying process. Pillaring graphene oxide sheets by co-deposition of colloidal-phase particle-based spacers has the potential to partially restore the large monolayer surface. Surface areas as high as 1000 m 2 g -1 are demonstrated here through colloidal-phase deposition of graphene oxide with water-dispersible aryl-sulfonated ultrafine carbon black as a pillaring agent.

Sport stacking in auditory and visual attention of grade 3 learners.

PubMed

Mortimer, J; Krysztofiak, J; Custard, S; McKune, A J

2011-08-01

The effect of sport stacking on auditory and visual attention in 32 Grade 3 children was examined using a randomised, cross-over design. Children were randomly assigned to a sport stacking (n=16) or arts/crafts group (n=16) with these activities performed over 3 wk. (12 30-min. sessions, 4 per week). This was followed by a 3-wk. wash-out period after which there was a cross-over and the 3-wk. intervention repeated, with the sports stacking group performing arts/crafts and the arts/crafts group performing sports stacking. Performance on the Integrated Visual and Auditory Continuous Performance Test, a measure of auditory and visual attention, was assessed before and after each of the 3-wk. interventions for each group. Comparisons indicated that sport stacking resulted in significant improvement in high demand function and fine motor regulation, while it caused a significant reduction in low demand function. Auditory and visual attention adaptations to sport stacking may be specific to the high demand nature of the task.

Inherent Driving Force for Charge Separation in Curved Stacks of Oligothiophenes

DOE PAGES

Wu, Qin

2015-01-30

Coexistence of high local charge mobility and an energy gradient can lead to efficient free charge carrier generation from geminate charge transfer states at the donor–acceptor interface in bulk heterojunction organic photovoltaics. It is, however, not clear what polymer microstructures can support such coexistence. Using recent methods from density functional theory, we propose that a stack of similarly curved oligothiophene chains can deliver the requirements for efficient charge separation. Curved stacks are stable because of the polymer’s strong π-stacking ability and because backbone torsions are flexible in neutral chains. However, energy of a charge in a polymer chain has remarkablymore » stronger dependence on torsions. The trend of increasing planarity in curved stacks effectively creates an energy gradient that drives charge in one direction. The curvature of these partially ordered stacks is found to beneficially interact with fullerenes for charge separation. The curved stacks, therefore, are identified as possible building blocks for interfacial structures that lead to efficient free carrier generation in high-performing organic photovoltaic systems.« less

Inherent Driving Force for Charge Separation in Curved Stacks of Oligothiophenes

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

Wu, Qin

Coexistence of high local charge mobility and an energy gradient can lead to efficient free charge carrier generation from geminate charge transfer states at the donor–acceptor interface in bulk heterojunction organic photovoltaics. It is, however, not clear what polymer microstructures can support such coexistence. Using recent methods from density functional theory, we propose that a stack of similarly curved oligothiophene chains can deliver the requirements for efficient charge separation. Curved stacks are stable because of the polymer’s strong π-stacking ability and because backbone torsions are flexible in neutral chains. However, energy of a charge in a polymer chain has remarkablymore » stronger dependence on torsions. The trend of increasing planarity in curved stacks effectively creates an energy gradient that drives charge in one direction. The curvature of these partially ordered stacks is found to beneficially interact with fullerenes for charge separation. The curved stacks, therefore, are identified as possible building blocks for interfacial structures that lead to efficient free carrier generation in high-performing organic photovoltaic systems.« less

Inter-layered clay stacks in Jurassic shales

NASA Technical Reports Server (NTRS)

Pye, K.; Krinsley, D. H.

1983-01-01

Scanning electron microscopy in the backscattered electron mode is used together with energy-dispersive X-ray microanalysis to show that Lower Jurassic shales from the North Sea Basin contain large numbers of clay mineral stacks up to 150 microns in size. Polished shale sections are examined to determine the size, shape orientation, textural relationships, and internal compositional variations of the clays. Preliminary evidence that the clay stacks are authigenic, and may have formed at shallow burial depths during early diagenesis, is presented.

Sampling and data handling methods for inhalable particulate sampling. Final report nov 78-dec 80

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

Smith, W.B.; Cushing, K.M.; Johnson, J.W.

1982-05-01

The report reviews the objectives of a research program on sampling and measuring particles in the inhalable particulate (IP) size range in emissions from stationary sources, and describes methods and equipment required. A computer technique was developed to analyze data on particle-size distributions of samples taken with cascade impactors from industrial process streams. Research in sampling systems for IP matter included concepts for maintaining isokinetic sampling conditions, necessary for representative sampling of the larger particles, while flowrates in the particle-sizing device were constant. Laboratory studies were conducted to develop suitable IP sampling systems with overall cut diameters of 15 micrometersmore » and conforming to a specified collection efficiency curve. Collection efficiencies were similarly measured for a horizontal elutriator. Design parameters were calculated for horizontal elutriators to be used with impactors, the EPA SASS train, and the EPA FAS train. Two cyclone systems were designed and evaluated. Tests on an Andersen Size Selective Inlet, a 15-micrometer precollector for high-volume samplers, showed its performance to be with the proposed limits for IP samplers. A stack sampling system was designed in which the aerosol is diluted in flow patterns and with mixing times simulating those in stack plumes.« less

Method and apparatus for adding electrolyte to a fuel cell stack

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

Congdon, J.V.; English, J.G.

1986-06-24

A process is described for adding electrolyte to a fuel cell stack, the stack comprising sheet-like elements defining a plurality of fuel cell units disposed one atop the other in abutting relationship, the units defining a substantially flat, vertically extending face, each unit including a cell comprising a pair of sheet-like spaced apart gas porous electrodes with a porous matrix layer sandwiched therebetween for retaining electrolyte during cell operation, each unit also including a sheet-like substantially non-porous separator, the separator being sandwiched between the cells of adjacent units. The improvement described here consists of: extending at least one of themore » sheet-like elements of each of a plurality of the fuel cell units outwardly from the stack face to define horizontal tabs disposed one above the other; depositing dilute electrolyte directly from electrolyte supply means upon substantially the full length, parallel to the stack face, of at least the uppermost tab, the tabs being constructed and arranged such that at least a portion of the deposited electrolyte cascades from tab to tab and down the face of the stack, the deposited electrolyte being absorbed by capillary action into the elements of the stack, the step of depositing continuing until all of the electrodes and matrix layers of the stack are fully saturated with the dilute electrolyte; and thereafter evaporating liquid from the saturated elements under controlled conditions of humidity and temperature until the stack has a desired electrolyte volume and electrolyte concentration therein.« less

Stacking and determination of phenazine-1-carboxylic acid with low pKa in soil via moving reaction boundary formed by alkaline and double acidic buffers in capillary electrophoresis.

PubMed

Sun, Chong; Yang, Xiao-Di; Fan, Liu-Yin; Zhang, Wei; Xu, Yu-Quan; Cao, Cheng-Xi

2011-04-01

As shown herein, a normal moving reaction boundary (MRB) formed by an alkaline buffer and a single acidic buffer had poor stacking to the new important plant growth promoter of phenazine-1-carboxylic acid (PCA) in soil due to the leak induced by its low pK(a). To stack the PCA with low pK(a) efficiently, a novel stacking system of MRB was developed, which was formed by an alkaline buffer and double acidic buffers (viz., acidic sample and blank buffers). With the novel system, the PCA leaking into the blank buffer from the sample buffer could be well stacked by the prolonged MRB formed between the alkaline buffer and blank buffer. The relevant mechanism of stacking was discussed briefly. The stacking system, coupled with sample pretreatment, could achieve a 214-fold increase of PCA sensitivity under the optimal conditions (15 mM (pH 11.5) Gly-NaOH as the alkaline buffer, 15 mM (pH 3.0) Gly-HCl-acetonitrile (20%, v/v) as the acidic sample buffer, 15 mM (pH 3.0) Gly-HCl as the blank buffer, 3 min 13 mbar injection of double acidic buffers, benzoic acid as the internal standard, 75 μm i.d. × 53 cm (44 cm effective length) capillary, 25 kV and 248 nm). The limit of detection of PCA in soil was decreased to 17 ng/g, the intra-day and inter-day precision values (expressed as relative standard deviations) were 3.17-4.24% and 4.17-4.87%, respectively, and the recoveries of PCA at three concentration levels changed from 52.20% to 102.61%. The developed method could be used for the detection of PCA in soil at trace level.

Supra-Nanoparticle Functional Assemblies through Programmable Stacking

DOE PAGES

Tian, Cheng; Cordeiro, Marco Aurelio L.; Lhermitte, Julien; ...

2017-05-25

The quest for the by-design assembly of material and devices from nanoscale inorganic components is well recognized. Conventional self-assembly is often limited in its ability to control material morphology and structure simultaneously. We report a general method of assembling nanoparticles in a linear “pillar” morphology with regulated internal configurations. Our approach is inspired by supramolecular systems, where intermolecular stacking guides the assembly process to form diverse linear morphologies. Programmable stacking interactions were realized through incorporation of DNA coded recognition between the designed planar nanoparticle clusters. This resulted in the formation of multilayered pillar architectures with a well-defined internal nanoparticle organization.more » Furthermore, by controlling the number, position, size, and composition of the nanoparticles in each layer, a broad range of nanoparticle pillars were assembled and characterized in detail. In addition, we demonstrated the utility of this stacking assembly strategy for investigating plasmonic and electrical transport properties.« less

Supra-Nanoparticle Functional Assemblies through Programmable Stacking

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

Tian, Cheng; Cordeiro, Marco Aurelio L.; Lhermitte, Julien

The quest for the by-design assembly of material and devices from nanoscale inorganic components is well recognized. Conventional self-assembly is often limited in its ability to control material morphology and structure simultaneously. We report a general method of assembling nanoparticles in a linear “pillar” morphology with regulated internal configurations. Our approach is inspired by supramolecular systems, where intermolecular stacking guides the assembly process to form diverse linear morphologies. Programmable stacking interactions were realized through incorporation of DNA coded recognition between the designed planar nanoparticle clusters. This resulted in the formation of multilayered pillar architectures with a well-defined internal nanoparticle organization.more » Furthermore, by controlling the number, position, size, and composition of the nanoparticles in each layer, a broad range of nanoparticle pillars were assembled and characterized in detail. In addition, we demonstrated the utility of this stacking assembly strategy for investigating plasmonic and electrical transport properties.« less

Multibands tunneling in AAA-stacked trilayer graphene

NASA Astrophysics Data System (ADS)

Redouani, Ilham; Jellal, Ahmed; Bahaoui, Abdelhadi; Bahlouli, Hocine

2018-04-01

We study the electronic transport through np and npn junctions for AAA-stacked trilayer graphene. Two kinds of gates are considered where the first is a single gate and the second is a double gate. After obtaining the solutions for the energy spectrum, we use the transfer matrix method to determine the three transmission probabilities for each individual cone τ = 0 , ± 1 . We show that the quasiparticles in AAA-stacked trilayer graphene are not only chiral but also labeled by an additional cone index τ. The obtained bands are composed of three Dirac cones that depend on the chirality indexes. We show that there is perfect transmission for normal or near normal incidence, which is a manifestation of the Klein tunneling effect. We analyze also the corresponding total conductance, which is defined as the sum of the conductance channels in each individual cone. Our results are numerically discussed and compared with those obtained for ABA- and ABC-stacked trilayer graphene.

Uranium chemistry in stack solutions and leachates of phosphogypsum disposed at a coastal area in Cyprus.

PubMed

Lysandrou, M; Pashalidis, I

2008-02-01

The effect of the matrix composition (main constituents) on the concentration and chemical behavior of uranium in phosphogypsum stack solutions and leachates has been investigated. Solid and aqueous samples were taken from three different sub-areas of a phosphogypsum stack at a coastal area in Vasilikos (Cyprus). The sub-areas are characterized whether by their acidity (e.g. "aged" and "non-aged" phosphogypsum) or by their salt content, originating from pulping water during wet stacking or (after deposition) from the adjacent sea. Measurements in stack solutions and leachates showed that phosphogypsum characteristics affect both, the concentration and the chemical behavior of uranium in solution. Uranium concentration in solutions of increased salinity is up to three orders of magnitude higher than in solutions of low salinity and this is attributed to the effect of ionic strength on the solubility of phosphogypsum. Modelling showed that uranium in stack solutions is predominantly present in the form of uranium(VI) phosphate complexes (e.g. UO(2)(H(2)PO(4))(2), UO(2)HPO(4)), whereas in leachates uranium(VI) fluoro complexes (e.g. UO(2)F(2), UO(2)F(3)(-)) are predominant in solution. The latter indicates that elution of uranium from phosphogypsum takes places most probably in the form of fluoro complexes. Both, effective elution by saline water and direct migration of uranium to the sea, where it forms very stable uranium(VI) carbonato complexes, indicate that the adjacent sea will be the final receptor of uranium released from Vasilikos phosphogypsum.

Radiation-Tolerant Intelligent Memory Stack - RTIMS

NASA Technical Reports Server (NTRS)

Ng, Tak-kwong; Herath, Jeffrey A.

2011-01-01

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

Microseismic source locations with deconvolution migration

NASA Astrophysics Data System (ADS)

Wu, Shaojiang; Wang, Yibo; Zheng, Yikang; Chang, Xu

2018-03-01

Identifying and locating microseismic events are critical problems in hydraulic fracturing monitoring for unconventional resources exploration. In contrast to active seismic data, microseismic data are usually recorded with unknown source excitation time and source location. In this study, we introduce deconvolution migration by combining deconvolution interferometry with interferometric cross-correlation migration (CCM). This method avoids the need for the source excitation time and enhances both the spatial resolution and robustness by eliminating the square term of the source wavelets from CCM. The proposed algorithm is divided into the following three steps: (1) generate the virtual gathers by deconvolving the master trace with all other traces in the microseismic gather to remove the unknown excitation time; (2) migrate the virtual gather to obtain a single image of the source location and (3) stack all of these images together to get the final estimation image of the source location. We test the proposed method on complex synthetic and field data set from the surface hydraulic fracturing monitoring, and compare the results with those obtained by interferometric CCM. The results demonstrate that the proposed method can obtain a 50 per cent higher spatial resolution image of the source location, and more robust estimation with smaller errors of the localization especially in the presence of velocity model errors. This method is also beneficial for source mechanism inversion and global seismology applications.

A Urea Biosensor from Stacked Sol-Gel Films with Immobilized Nile Blue Chromoionophore and Urease Enzyme.

PubMed

Alqasaimeh, Muawia Salameh; Heng, Lee Yook; Ahmad, Musa

2007-10-11

An optical urea biosensor was fabricated by stacking several layers of sol-gelfilms. The stacking of the sol-gel films allowed the immobilization of a Nile Bluechromoionophore (ETH 5294) and urease enzyme separately without the need of anychemical attachment procedure. The absorbance response of the biosensor was monitoredat 550 nm, i.e. the deprotonation of the chromoionophore. This multi-layer sol-gel filmformat enabled higher enzyme loading in the biosensor to be achieved. The urea opticalbiosensor constructed from three layers of sol-gel films that contained urease demonstrateda much wider linear response range of up to 100 mM urea when compared with biosensorsthat constructed from 1-2 layers of films. Analysis of urea in urine samples with thisoptical urea biosensor yielded results similar to that determined by a spectrophotometricmethod using the reagent p-dimethylaminobenzaldehyde (R² = 0.982, n = 6). The averagerecovery of urea from urine samples using this urea biosensor is approximately 103%.

A Urea Biosensor from Stacked Sol-Gel Films with Immobilized Nile Blue Chromoionophore and Urease Enzyme

PubMed Central

Alqasaimeh, Muawia Salameh; Heng, Lee Yook; Ahmad, Musa

2007-01-01

An optical urea biosensor was fabricated by stacking several layers of sol-gel films. The stacking of the sol-gel films allowed the immobilization of a Nile Blue chromoionophore (ETH 5294) and urease enzyme separately without the need of any chemical attachment procedure. The absorbance response of the biosensor was monitored at 550 nm, i.e. the deprotonation of the chromoionophore. This multi-layer sol-gel film format enabled higher enzyme loading in the biosensor to be achieved. The urea optical biosensor constructed from three layers of sol-gel films that contained urease demonstrated a much wider linear response range of up to 100 mM urea when compared with biosensors that constructed from 1-2 layers of films. Analysis of urea in urine samples with this optical urea biosensor yielded results similar to that determined by a spectrophotometric method using the reagent p-dimethylaminobenzaldehyde (R2 = 0.982, n = 6). The average recovery of urea from urine samples using this urea biosensor is approximately 103%.

High Efficiency Stacked Organic Light-Emitting Diodes Employing Li2O as a Connecting Layer

NASA Astrophysics Data System (ADS)

Kanno, Hiroshi; Hamada, Yuji; Nishimura, Kazuki; Okumoto, Kenji; Saito, Nobuo; Ishida, Hiroki; Takahashi, Hisakazu; Shibata, Kenichi; Mameno, Kazunobu

2006-12-01

We demonstrate the high-efficiency stacked organic light-emitting diodes (OLEDs) introducing new connecting layers. In the green stacked OLEDs, the external efficiencies increase proportionally to the number of the stacked units without suffering the decrease in power efficiency. The current, power and external efficiencies at 0.5 mA/cm2 of the stacked OLED with six stacked units (6-stacked OLED) have reached 235 cd/A, 46.6 lm/W, and 65.8%, respectively. Furthermore, we have applied the connecting layers to a white stacked OLED and fabricated an active-matrix full-color display with a low temperature polysilicon thin film transistor backplane. In the device, the current efficiency of the white 2-stacked OLED is enhanced by a factor of 2.2. The initial luminance drop is significantly suppressed for the white 2-stacked OLED compared to 1-stacked OLED. The proposed white stacked OLED technology can be applied to a full-color display for a practical use.

Stacked Fresnel Zone Plates for High Energy X-rays

NASA Astrophysics Data System (ADS)

Snigireva, Irina; Snigirev, Anatoly; Vaughan, Gavin; Di Michiel, Marco; Kohn, Viktor; Yunkin, Vyacheslav; Grigoriev, Maxim

2007-01-01

A stacking technique was developed in order to increase focusing efficiency of Fresnel zone plates (FZP) at high energies. Two identical Si chips each of which containing 9 FZPs were used for stacking. Alignment of the chips was achieved by on-line observation of the moiré pattern. The formation of moiré patterns was studied theoretically and experimentally at different experimental conditions. To provide the desired stability Si-chips were bonded together with slow solidification speed epoxy glue. A technique of angular alignment in order to compensate a linear displacement in the process of gluing was proposed. Two sets of stacked FZPs were experimentally tested to focus 15 and 50 keV x rays. The gain in the efficiency by factor 2.5 was demonstrated at 15 keV. The focal spot of 1.8 μm vertically and 14 μm horizontally with 35% efficiency was measured at 50 keV. Forecast for the stacking of nanofocusing FZPs was discussed.

Robust multivariate nonparametric tests for detection of two-sample location shift in clinical trials

PubMed Central

Jiang, Xuejun; Guo, Xu; Zhang, Ning; Wang, Bo

2018-01-01

This article presents and investigates performance of a series of robust multivariate nonparametric tests for detection of location shift between two multivariate samples in randomized controlled trials. The tests are built upon robust estimators of distribution locations (medians, Hodges-Lehmann estimators, and an extended U statistic) with both unscaled and scaled versions. The nonparametric tests are robust to outliers and do not assume that the two samples are drawn from multivariate normal distributions. Bootstrap and permutation approaches are introduced for determining the p-values of the proposed test statistics. Simulation studies are conducted and numerical results are reported to examine performance of the proposed statistical tests. The numerical results demonstrate that the robust multivariate nonparametric tests constructed from the Hodges-Lehmann estimators are more efficient than those based on medians and the extended U statistic. The permutation approach can provide a more stringent control of Type I error and is generally more powerful than the bootstrap procedure. The proposed robust nonparametric tests are applied to detect multivariate distributional difference between the intervention and control groups in the Thai Healthy Choices study and examine the intervention effect of a four-session motivational interviewing-based intervention developed in the study to reduce risk behaviors among youth living with HIV. PMID:29672555

Performance model of a recirculating stack nickel hydrogen cell

NASA Technical Reports Server (NTRS)

Zimmerman, Albert H.

1994-01-01

A theoretical model of the nickel hydrogen battery cell has been utilized to describe the chemical and physical changes during charge and overcharge in a recirculating stack nickel hydrogen cell. In particular, the movement of gas and electrolyte have been examined as a function of the amount of electrolyte put into the cell stack during cell activation, and as a function of flooding in regions of the gas screen in this cell design. Additionally, a two-dimensional variation on this model has been utilized to describe the effects of non-uniform loading in the nickel-electrode on the movement of gas and electrolyte within the recirculating stack nickel hydrogen cell. The type of nonuniform loading that has been examined here is that associated with higher than average loading near the surface of the sintered nickel electrode, a condition present to some degree in many nickel electrodes made by electrochemical impregnation methods. The effects of high surface loading were examined primarily under conditions of overcharge, since the movement of gas and electrolyte in the overcharging condition was typically where the greatest effects of non-uniform loading were found. The results indicate that significant changes in the capillary forces between cell components occur as the percentage of free volume in the stack filled by electrolyte becomes very high. These changes create large gradients in gas-filled space and oxygen concentrations near the boundary between the separator and the hydrogen electrode when the electrolyte fill is much greater than about 95 percent of the stack free volume. At lower electrolyte fill levels, these gaseous and electrolyte gradients become less extreme, and shift through the separator towards the nickel electrode. Similarly, flooding of areas in the gas screen cause higher concentrations of oxygen gas to approach the platinum/hydrogen electrode that is opposite the back side of the nickel electrode. These results illustrate the need for

Biogenesis of Golgi Stacks in Imaginal Discs of Drosophila melanogaster

PubMed Central

Kondylis, Vangelis; Goulding, Sarah E.; Dunne, Jonathan C.; Rabouille, Catherine

2001-01-01

We provide a detailed description of Golgi stack biogenesis that takes place in vivo during one of the morphogenetic events in the lifespan of Drosophila melanogaster. In early third-instar larvae, small clusters consisting mostly of vesicles and tubules were present in epithelial imaginal disk cells. As larvae progressed through mid- and late-third instar, these larval clusters became larger but also increasingly formed cisternae, some of which were stacked. In white pupae, the typical Golgi stack was observed. We show that larval clusters are Golgi stack precursors by 1) localizing various Golgi-specific markers to the larval clusters by electron and immunofluorescence confocal microscopy, 2) driving this conversion in wild-type larvae incubated at 37°C for 2 h, and 3) showing that this conversion does not take place in an NSF1 mutant (comt 17). The biological significance of this conversion became clear when we found that the steroid hormone 20-hydroxyecdysone (ecdysone) is critically involved in this conversion. In its absence, Golgi stack biogenesis did not occur and the larval clusters remained unaltered. We showed that dGM130 and sec23p expression increases approximately three- and fivefold, respectively, when discs are exposed to ecdysone in vivo and in vitro. Taken together, these results suggest that we have developed an in vivo system to study the ecdysone-triggered Golgi stack biogenesis. PMID:11514618

40 CFR 62.15230 - What types of stack tests must I conduct?

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 8 2010-07-01 2010-07-01 false What types of stack tests must I... August 30, 1999 Stack Testing § 62.15230 What types of stack tests must I conduct? Conduct initial and... matter, opacity, hydrogen chloride, and fugitive ash. ...

40 CFR 62.15230 - What types of stack tests must I conduct?

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 8 2011-07-01 2011-07-01 false What types of stack tests must I... August 30, 1999 Stack Testing § 62.15230 What types of stack tests must I conduct? Conduct initial and... matter, opacity, hydrogen chloride, and fugitive ash. ...

Geometric Patterns for Neighboring Bases Near the Stacked State in Nucleic Acid Strands.

PubMed

Sedova, Ada; Banavali, Nilesh K

2017-03-14

Structural variation in base stacking has been analyzed frequently in isolated double helical contexts for nucleic acids, but not as often in nonhelical geometries or in complex biomolecular environments. In this study, conformations of two neighboring bases near their stacked state in any environment are comprehensively characterized for single-strand dinucleotide (SSD) nucleic acid crystal structure conformations. An ensemble clustering method is used to identify a reduced set of representative stacking geometries based on pairwise distances between select atoms in consecutive bases, with multiple separable conformational clusters obtained for categories divided by nucleic acid type (DNA/RNA), SSD sequence, stacking face orientation, and the presence or absence of a protein environment. For both DNA and RNA, SSD conformations are observed that are either close to the A-form, or close to the B-form, or intermediate between the two forms, or further away from either form, illustrating the local structural heterogeneity near the stacked state. Among this large variety of distinct conformations, several common stacking patterns are observed between DNA and RNA, and between nucleic acids in isolation or in complex with proteins, suggesting that these might be stable stacking orientations. Noncanonical face/face orientations of the two bases are also observed for neighboring bases in the same strand, but their frequency is much lower, with multiple SSD sequences across categories showing no occurrences of such unusual stacked conformations. The resulting reduced set of stacking geometries is directly useful for stacking-energy comparisons between empirical force fields, prediction of plausible localized variations in single-strand structures near their canonical states, and identification of analogous stacking patterns in newly solved nucleic acid containing structures.

Nitride-based stacked laser diodes with a tunnel junction

NASA Astrophysics Data System (ADS)

Okawara, Satoru; Aoki, Yuta; Kuwabara, Masakazu; Takagi, Yasufumi; Maeda, Junya; Yoshida, Harumasa

2018-01-01

We report on nitride-based two-stack laser diodes with a tunnel junction for the first time. The stacked laser diode was monolithically grown by metalorganic vapor phase epitaxy. It was confirmed that the two-stack InGaN/GaN multiple-quantum-well laser diode with an emission wavelength of 394 nm exhibited laser oscillation up to a peak output power of over 10 W in the pulsed current mode. The upper and lower emitters of the device were capable of lasing at different threshold currents of 2.4 and 5.2 A with different slope efficiencies of 0.8 and 0.3 W/A, respectively.

Determination of deferasirox in human plasma by short-end injection and sweeping with a field-amplified sample stacking and micellar electrokinetic chromatography.

PubMed

Lin, Hung-Ju; Hsieh, Kun-Pin; Chiou, Shyh-Shin; Kou, Hwang-Shang; Wu, Shou-Mei

2016-11-30

A field-amplified sample stacking-sweeping micellar electrokinetic chromatography with short-end injection was established for determination of deferasirox (DFX) in plasma. DFX was extracted from plasma and reconstituted with deionized water (lower conductivity solution). Capillary (effective length, 10cm) was filled with background electrolyte (40mM phosphate buffer, pH 4.5, containing 20% methanol). After sample loading from outlet end at 5psi for 15s, separation was carried out by applying high voltage at 15kV for 10min. Sodium dodecyl sulfate (SDS) was used to sweep DFX for enhancing sensitivity. The optimal CE separation conditions were 40mM phosphate buffer at pH 4.5 containing 100mM SDS and 20% methanol. The analysis time was about 3.5min for DFX. The calibration curve of DFX was ranged from 1 to 20μg/ml. The linearity (r) was more than 0.998. RSD and RE in intra- and inter-day assays were all below 12.14%. The limit of detection (LOD, S/N=3) for DFX was 0.3μg/ml. The sensitivity enhancement factor between sweeping-FASS MEKC and capillary zone electrophoresis is 3.3. Finally, the method was applied for determination of DFX in β-thalassemia patients. Copyright © 2016 Elsevier B.V. All rights reserved.

40 CFR 63.307 - Standards for bypass/bleeder stacks.

Code of Federal Regulations, 2014 CFR

2014-07-01

... National Emission Standards for Coke Oven Batteries § 63.307 Standards for bypass/bleeder stacks. (a)(1.... (2) Coke oven emissions shall not be vented to the atmosphere through bypass/bleeder stacks, except.... (3) The owner or operator of a brownfield coke oven battery or a padup rebuild shall install such a...

40 CFR 63.307 - Standards for bypass/bleeder stacks.

Code of Federal Regulations, 2013 CFR

2013-07-01

... National Emission Standards for Coke Oven Batteries § 63.307 Standards for bypass/bleeder stacks. (a)(1.... (2) Coke oven emissions shall not be vented to the atmosphere through bypass/bleeder stacks, except.... (3) The owner or operator of a brownfield coke oven battery or a padup rebuild shall install such a...

40 CFR 63.307 - Standards for bypass/bleeder stacks.

Code of Federal Regulations, 2012 CFR

2012-07-01

... National Emission Standards for Coke Oven Batteries § 63.307 Standards for bypass/bleeder stacks. (a)(1.... (2) Coke oven emissions shall not be vented to the atmosphere through bypass/bleeder stacks, except.... (3) The owner or operator of a brownfield coke oven battery or a padup rebuild shall install such a...

40 CFR 60.1285 - What types of stack tests must I conduct?

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 6 2010-07-01 2010-07-01 false What types of stack tests must I... Modification or Reconstruction is Commenced After June 6, 2001 Stack Testing § 60.1285 What types of stack.../furans, cadmium, lead, mercury, particulate matter, opacity, hydrogen chloride, and fugitive ash. ...

40 CFR 60.1285 - What types of stack tests must I conduct?

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 6 2011-07-01 2011-07-01 false What types of stack tests must I... Modification or Reconstruction is Commenced After June 6, 2001 Stack Testing § 60.1285 What types of stack.../furans, cadmium, lead, mercury, particulate matter, opacity, hydrogen chloride, and fugitive ash. ...

Stacking Oxygen-Separation Cells

NASA Technical Reports Server (NTRS)

Schroeder, James E.

1991-01-01

Simplified configuration and procedure developed for assembly of stacks of solid-electrolyte cells separating oxygen from air electrochemically. Reduces number of components and thus reduces probability of such failures as gas leaks, breakdown of sensitive parts, and electrical open or short circuits. Previous, more complicated version of cell described in "Improved Zirconia Oxygen-Separation Cell" (NPO-16161).

Extent and relevance of stacking disorder in “ice Ic”

PubMed Central

Kuhs, Werner F.; Sippel, Christian; Falenty, Andrzej; Hansen, Thomas C.

2012-01-01

A solid water phase commonly known as “cubic ice” or “ice Ic” is frequently encountered in various transitions between the solid, liquid, and gaseous phases of the water substance. It may form, e.g., by water freezing or vapor deposition in the Earth’s atmosphere or in extraterrestrial environments, and plays a central role in various cryopreservation techniques; its formation is observed over a wide temperature range from about 120 K up to the melting point of ice. There was multiple and compelling evidence in the past that this phase is not truly cubic but composed of disordered cubic and hexagonal stacking sequences. The complexity of the stacking disorder, however, appears to have been largely overlooked in most of the literature. By analyzing neutron diffraction data with our stacking-disorder model, we show that correlations between next-nearest layers are clearly developed, leading to marked deviations from a simple random stacking in almost all investigated cases. We follow the evolution of the stacking disorder as a function of time and temperature at conditions relevant to atmospheric processes; a continuous transformation toward normal hexagonal ice is observed. We establish a quantitative link between the crystallite size established by diffraction and electron microscopic images of the material; the crystallite size evolves from several nanometers into the micrometer range with progressive annealing. The crystallites are isometric with markedly rough surfaces parallel to the stacking direction, which has implications for atmospheric sciences. PMID:23236184

Development and Applications of a Stage Stacking Procedure

NASA Technical Reports Server (NTRS)

Kulkarni, Sameer; Celestina, Mark L.; Adamczyk, John J.

2012-01-01

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.

Advancements in high-power diode laser stacks for defense applications

NASA Astrophysics Data System (ADS)

Pandey, Rajiv; Merchen, David; Stapleton, Dean; Patterson, Steve; Kissel, Heiko; Fassbender, Wilhlem; Biesenbach, Jens

2012-06-01

This paper reports on the latest advancements in vertical high-power diode laser stacks using micro-channel coolers, which deliver the most compact footprint, power scalability and highest power/bar of any diode laser package. We present electro-optical (E-O) data on water-cooled stacks with wavelengths ranging from 7xx nm to 9xx nm and power levels of up to 5.8kW, delivered @ 200W/bar, CW mode, and a power-conversion efficiency of >60%, with both-axis collimation on a bar-to-bar pitch of 1.78mm. Also, presented is E-O data on a compact, conductively cooled, hardsoldered, stack package based on conventional CuW and AlN materials, with bar-to-bar pitch of 1.8mm, delivering average power/bar >15W operating up to 25% duty cycle, 10ms pulses @ 45C. The water-cooled stacks can be used as pump-sources for diode-pumped alkali lasers (DPALs) or for more traditional diode-pumped solid-state lasers (DPSSL). which are power/brightness scaled for directed energy weapons applications and the conductively-cooled stacks as illuminators.

Correlative weighted stacking for seismic data in the wavelet domain

USGS Publications Warehouse

Zhang, S.; Xu, Y.; Xia, J.; ,

2004-01-01

Horizontal stacking plays a crucial role for modern seismic data processing, for it not only compresses random noise and multiple reflections, but also provides a foundational data for subsequent migration and inversion. However, a number of examples showed that random noise in adjacent traces exhibits correlation and coherence. The average stacking and weighted stacking based on the conventional correlative function all result in false events, which are caused by noise. Wavelet transform and high order statistics are very useful methods for modern signal processing. The multiresolution analysis in wavelet theory can decompose signal on difference scales, and high order correlative function can inhibit correlative noise, for which the conventional correlative function is of no use. Based on the theory of wavelet transform and high order statistics, high order correlative weighted stacking (HOCWS) technique is presented in this paper. Its essence is to stack common midpoint gathers after the normal moveout correction by weight that is calculated through high order correlative statistics in the wavelet domain. Synthetic examples demonstrate its advantages in improving the signal to noise (S/N) ration and compressing the correlative random noise.

Stacking dependence of carrier transport properties in multilayered black phosphorous

NASA Astrophysics Data System (ADS)

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

2016-02-01

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.

Extended Life PZT Stack Test Fixture

NASA Technical Reports Server (NTRS)

Badescu, Mircea; Sherrit, S.; Bao, X.; Aldrich, J.; Bar-Cohen, Y.; Jones, C.

2009-01-01

Piezoelectric stacks are being sought to be used as actuators for precision positioning and deployment of mechanisms in future planetary missions. Beside the requirement for very high operation reliability, these actuators are required for operation at space environments that are considered harsh compared to normal terrestrial conditions.These environmental conditions include low and high temperatures and vacuum or high pressure. Additionally, the stacks are subjected to high stress and in some applications need to operate with a very long lifetime durability.Many of these requirements are beyond the current industry design margins for nominal terrestrial applications. In order to investigate some of the properties that will indicate the durability of such actuators and their limitations we have developed a new type of test fixture that can be easily integrated in various test chambers for simulating environmental conditions, can provide access for multiple measurements while being exposed to adjustable stress levels. We designed and built two test fixtures and these fixtures were made to be adjustable for testing stacks with different dimensions and can be easily used in small or large numbers. The properties that were measured using these fixtures include impedance, capacitance, dielectric loss factor, leakage current, displacement, breakdown voltage, and lifetime performance. The fixtures characteristics and the test capabilities are presented in this paper.

Electric-field-induced plasmon in AA-stacked bilayer graphene

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

Chuang, Y.C., E-mail: yingchih.chuang@gmail.com; Wu, J.Y., E-mail: yarst5@gmail.com; Lin, M.F., E-mail: mflin@mail.ncku.edu.tw

2013-12-15

The collective excitations in AA-stacked bilayer graphene for a perpendicular electric field are investigated analytically within the tight-binding model and the random-phase approximation. Such a field destroys the uniform probability distribution of the four sublattices. This drives a symmetry breaking between the intralayer and interlayer polarization intensities from the intrapair band excitations. A field-induced acoustic plasmon thus emerges in addition to the strongly field-tunable intrinsic acoustic and optical plasmons. At long wavelengths, the three modes show different dispersions and field dependence. The definite physical mechanism of the electrically inducible and tunable mode can be expected to also be present inmore » other AA-stacked few-layer graphenes. -- Highlights: •The analytical derivations are performed by the tight-binding model. •An electric field drives the non-uniformity of the charge distribution. •A symmetry breaking between the intralayer and interlayer polarizations is illustrated. •An extra plasmon emerges besides two intrinsic modes in AA-stacked bilayer graphene. •The mechanism of a field-induced mode is present in AA-stacked few-layer graphenes.« less

Hard X-ray focusing by stacked Fresnel zone plates

NASA Astrophysics Data System (ADS)

Snigireva, Irina; Snigirev, Anatoly; Kohn, Viktor; Yunkin, Vyacheslav; Grigoriev, Maxim; Kuznetsov, Serguei; Vaughan, Gavin; Di Michiel, Marco

2007-09-01

Stacking technique was developed in order to increase focusing efficiency of Fresnel zone plates at high energies. Two identical Si chips each of which containing Fresnel zone plates were used for stacking. Alignment of the chips was achieved by on-line observation of the moiré pattern from the two zone plates. The formation of moiré patterns was studied theoretically and experimentally at different experimental conditions. To provide the desired stability Si-chips with zone plates were bonded together with slow solidification speed epoxy glue. Technique of angular alignment in order to compensate a linear displacement in the process of gluing was proposed. Two sets of stacked FZPs were produced and experimentally tested to focus 15 and 50 keV X-rays. Gain in the efficiency by factor 2.5 was demonstrated at 15 keV. Focal spot of 1.8 μm vertically and 14 μm horizontally with 35% efficiency was measured at 50 keV. Forecast for the stacking of nanofocusing Fresnel zone plates was discussed.

Mechanical sieve for screening mineral samples

NASA Technical Reports Server (NTRS)

Otto, W. P.

1970-01-01

Mechanical sieve consists of three horizontal screens mounted in a vertical stack. A combination of rotation and tapping produces an even flow across the screens, dislodges trapped particles, an ensures rapid segregation of the sample.

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

PubMed

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

2017-06-16

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.

Oxidation precursor dependence of atomic layer deposited Al2O3 films in a-Si:H(i)/Al2O3 surface passivation stacks.

PubMed

Xiang, Yuren; Zhou, Chunlan; Jia, Endong; Wang, Wenjing

2015-01-01

In order to obtain a good passivation of a silicon surface, more and more stack passivation schemes have been used in high-efficiency silicon solar cell fabrication. In this work, we prepared a-Si:H(i)/Al2O3 stacks on KOH solution-polished n-type solar grade mono-silicon(100) wafers. For the Al2O3 film deposition, both thermal atomic layer deposition (T-ALD) and plasma enhanced atomic layer deposition (PE-ALD) were used. Interface trap density spectra were obtained for Si passivation with a-Si films and a-Si:H(i)/Al2O3 stacks by a non-contact corona C-V technique. After the fabrication of a-Si:H(i)/Al2O3 stacks, the minimum interface trap density was reduced from original 3 × 10(12) to 1 × 10(12) cm(-2) eV(-1), the surface total charge density increased by nearly one order of magnitude for PE-ALD samples and about 0.4 × 10(12) cm(-2) for a T-ALD sample, and the carrier lifetimes increased by a factor of three (from about 10 μs to about 30 μs). Combining these results with an X-ray photoelectron spectroscopy analysis, we discussed the influence of an oxidation precursor for ALD Al2O3 deposition on Al2O3 single layers and a-Si:H(i)/Al2O3 stack surface passivation from field-effect passivation and chemical passivation perspectives. In addition, the influence of the stack fabrication process on the a-Si film structure was also discussed in this study.

Progress Update: Stack Project Complete

ScienceCinema

Cody, Tom

2017-12-12

Progress update from the Savannah River Site. The 75 foot 293 F Stack, built for plutonium production, was cut down to size in order to prevent injury or release of toxic material if the structure were to collapse due to harsh weather.

Effects of time and sampling location on concentrations of β-hydroxybutyric acid in dairy cows.

PubMed

Mahrt, A; Burfeind, O; Heuwieser, W

2014-01-01

Two trials were conducted to examine factors potentially influencing the measurement of blood β-hydroxybutyric acid (BHBA) in dairy cows. The objective of the first trial was to study effects of sampling time on BHBA concentration in continuously fed dairy cows. Furthermore, we determined test characteristics of a single BHBA measurement at a random time of the day to diagnose subclinical ketosis considering commonly used cut-points (1.2 and 1.4 mmol/L). Finally, we set out to evaluate if test characteristics could be enhanced by repeating measurements after different time intervals. During 4 herd visits, a total of 128 cows (8 to 28 d in milk) fed 10 times daily were screened at 0900 h and preselected by BHBA concentration. Blood samples were drawn from the tail vessels and BHBA concentrations were measured using an electronic BHBA meter (Precision Xceed, Abbott Diabetes Care Ltd., Witney, UK). Cows with BHBA concentrations ≥0.8 mmol/L at this time were enrolled in the trial (n=92). Subsequent BHBA measurements took place every 3h for a total of 8 measurements during 24 h. The effect of sampling time on BHBA concentrations was tested in a repeated-measures ANOVA repeating sampling time. Sampling time did not affect BHBA concentrations in continuously fed dairy cows. Defining the average daily BHBA concentration calculated from the 8 measurements as the gold standard, a single measurement at a random time of the day to diagnose subclinical ketosis had a sensitivity of 0.90 or 0.89 at the 2 BHBA cut-points (1.2 and 1.4 mmol/L). Specificity was 0.88 or 0.90 using the same cut-points. Repeating measurements after different time intervals improved test characteristics only slightly. In the second experiment, we compared BHBA concentrations of samples drawn from 3 different blood sampling locations (tail vessels, jugular vein, and mammary vein) of 116 lactating dairy cows. Concentrations of BHBA differed in samples from the 3 sampling locations. Mean BHBA

Individual detection of genetically modified maize varieties in non-identity-preserved maize samples.

PubMed

Akiyama, Hiroshi; Sakata, Kozue; Kondo, Kazunari; Tanaka, Asako; Liu, Ming S; Oguchi, Taichi; Furui, Satoshi; Kitta, Kazumi; Hino, Akihiro; Teshima, Reiko

2008-03-26

In many countries, the labeling of grains and feed- and foodstuffs is mandatory if the genetically modified organism (GMO) content exceeds a certain level of approved GM varieties. The GMO content in a maize sample containing the combined-trait (stacked) GM maize as determined by the currently available methodology is likely to be overestimated. However, there has been little information in the literature on the mixing level and varieties of stacked GM maize in real sample grains. For the first time, the GMO content of non-identity-preserved (non-IP) maize samples imported from the United States has been successfully determined by using a previously developed individual kernel detection system coupled to a multiplex qualitative PCR method followed by multichannel capillary gel electrophoresis system analysis. To clarify the GMO content in the maize samples imported from the United States, determine how many stacked GM traits are contained therein, and which GM trait varieties frequently appeared in 2005, the GMO content (percent) on a kernel basis and the varieties of the GM kernels in the non-IP maize samples imported from the United States were investigated using the individual kernel analysis system. The average (+/-standard deviation) of the GMO contents on a kernel basis in five non-IP sample lots was determined to be 51.0+/-21.6%, the percentage of a single GM trait grains was 39%, and the percentage of the stacked GM trait grains was 12%. The MON810 grains and NK603 grains were the most frequent varieties in the single GM traits. The most frequent stacked GM traits were the MON810xNK603 grains. In addition, the present study would provide the answer and impact for the quantification of GM maize content in the GM maize kernels on labeling regulation.

Role of SiC substrate surface on local tarnishing of deposited silver mirror stacks

NASA Astrophysics Data System (ADS)

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

2018-04-01

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.

Heteroaromatic π-Stacking Energy Landscapes

PubMed Central

2014-01-01

In this study we investigate π-stacking interactions of a variety of aromatic heterocycles with benzene using dispersion corrected density functional theory. We calculate extensive potential energy surfaces for parallel-displaced interaction geometries. We find that dispersion contributes significantly to the interaction energy and is complemented by a varying degree of electrostatic interactions. We identify geometric preferences and minimum interaction energies for a set of 13 5- and 6-membered aromatic heterocycles frequently encountered in small drug-like molecules. We demonstrate that the electrostatic properties of these systems are a key determinant for their orientational preferences. The results of this study can be applied in lead optimization for the improvement of stacking interactions, as it provides detailed energy landscapes for a wide range of coplanar heteroaromatic geometries. These energy landscapes can serve as a guide for ring replacement in structure-based drug design. PMID:24773380

TEM study on relationship between stacking faults and non-basal dislocations in Mg

NASA Astrophysics Data System (ADS)

Zhang, Dalong; Jiang, Lin; Schoenung, Julie M.; Mahajan, Subhash; Lavernia, Enrique J.

2015-12-01

Recent interest in the study of stacking faults and non-basal slip in Mg alloys is partly based on the argument that these phenomena positively influence mechanical behaviour. Inspection of the published literature, however, reveals that there is a lack of fundamental information on the mechanisms that govern the formation of stacking faults, especially I1-type stacking faults (I1 faults). Moreover, controversial and sometimes contradictory mechanisms have been proposed concerning the interactions between stacking faults and dislocations. Therefore, we describe a fundamental transmission electron microscope investigation on Mg 2.5 at. % Y (Mg-2.5Y) processed via hot isostatic pressing (HIP) and extrusion at 623 K. In the as-HIPed Mg-2.5Y, many and dislocations, together with some dislocations were documented, but no stacking faults were observed. In contrast, in the as-extruded Mg-2.5Y, a relatively high density of stacking faults and some non-basal dislocations were documented. Specifically, there were three different cases for the configurations of observed stacking faults. Case (I): pure I2 faults; Case (II): mixture of I1 faults and non-basal dislocations having component, together with basal dislocations; Case (III): mixture of predominant I2 faults and rare I1 faults, together with jog-like dislocation configuration. By comparing the differences in extended defect configurations, we propose three distinct stacking fault formation mechanisms for each case in the context of slip activity and point defect generation during extrusion. Furthermore, we discuss the role of stacking faults on deformation mechanisms in the context of dynamic interactions between stacking faults and non-basal slip.

Test of Hydrogen-Oxygen PEM Fuel Cell Stack at NASA Glenn Research Center

NASA Technical Reports Server (NTRS)

Bents, David J.; Scullin, Vincent J.; Chang, Bei-Jiann; Johnson, Donald W.; Garcia, Christopher P.; Jakupca, Ian J.

2003-01-01

This paper describes performance characterization tests of a 64 cell hydrogen oxygen PEM fuel cell stack at NASA Glenn Research Center in February 2003. The tests were part of NASA's ongoing effort to develop a regenerative fuel cell for aerospace energy storage applications. The purpose of the tests was to verify capability of this stack to operate within a regenerative fuel cell, and to compare performance with earlier test results recorded by the stack developer. Test results obtained include polarization performance of the stack at 50 and 100 psig system pressure, and a steady state endurance run at 100 psig. A maximum power output of 4.8 kWe was observed during polarization runs, and the stack sustained a steady power output of 4.0 kWe during the endurance run. The performance data obtained from these tests compare reasonably close to the stack developer's results although some additional spread between best to worst performing cell voltages was observed. Throughout the tests, the stack demonstrated the consistent performance and repeatable behavior required for regenerative fuel cell operation.

RADON MITIGATION EFFECTS OF PASSIVE STACKS IN RESIDENTIAL NEW CONSTRUCTION

EPA Science Inventory

The paper discusses the effects of passive stacks in mitigating radon levels in residential new construction. Although passive stacks have been installed as a radon resistant measure in new houses, little quantitative data on their performance has been collected. This study invol...

A trait stacking system via intra-genomic homologous recombination.

PubMed

Kumar, Sandeep; Worden, Andrew; Novak, Stephen; Lee, Ryan; Petolino, Joseph F

2016-11-01

A gene targeting method has been developed, which allows the conversion of 'breeding stacks', containing unlinked transgenes into a 'molecular stack' and thereby circumventing the breeding challenges associated with transgene segregation. A gene targeting method has been developed for converting two unlinked trait loci into a single locus transgene stack. The method utilizes intra-genomic homologous recombination (IGHR) between stably integrated target and donor loci which share sequence homology and nuclease cleavage sites whereby the donor contains a promoterless herbicide resistance transgene. Upon crossing with a zinc finger nuclease (ZFN)-expressing plant, double-strand breaks (DSB) are created in both the stably integrated target and donor loci. DSBs flanking the donor locus result in intra-genomic mobilization of a promoterless selectable marker-containing donor sequence, which can be utilized as a template for homology-directed repair of a concomitant DSB at the target locus resulting in a functional selectable marker via nuclease-mediated cassette exchange (NMCE). The method was successfully demonstrated in maize using a glyphosate tolerance gene as a donor whereby up to 3.3 % of the resulting progeny embryos cultured on selection medium regenerated plants with the donor sequence integrated into the target locus. The process could be extended to multiple cycles of trait stacking by virtue of a unique intron sequence homology for NMCE between the target and the donor loci. This is the first report that describes NMCE via IGHR, thereby enabling trait stacking using conventional crossing.

Stacked-unstacked equilibrium at the nick site of DNA.

PubMed

Protozanova, Ekaterina; Yakovchuk, Peter; Frank-Kamenetskii, Maxim D

2004-09-17

Stability of duplex DNA with respect to separation of complementary strands is crucial for DNA executing its major functions in the cell and it also plays a central role in major biotechnology applications of DNA: DNA sequencing, polymerase chain reaction, and DNA microarrays. Two types of interaction are well known to contribute to DNA stability: stacking between adjacent base-pairs and pairing between complementary bases. However, their contribution into the duplex stability is yet to be determined. Now we fill this fundamental gap in our knowledge of the DNA double helix. We have prepared a series of 32, 300 bp-long DNA fragments with solitary nicks in the same position differing only in base-pairs flanking the nick. Electrophoretic mobility of these fragments in the gel has been studied. Assuming the equilibrium between stacked and unstacked conformations at the nick site, all 32 stacking free energy parameters have been obtained. Only ten of them are essential and they govern the stacking interactions between adjacent base-pairs in intact DNA double helix. A full set of DNA stacking parameters has been determined for the first time. From these data and from a well-known dependence of DNA melting temperature on G.C content, the contribution of base-pairing into duplex stability has been estimated. The obtained energy parameters of the DNA double helix are of paramount importance for understanding sequence-dependent DNA flexibility and for numerous biotechnology applications.

Primary esophageal mucosa-associated lymphoid tissue lymphoma diagnosed by using stacked forceps biopsy.

PubMed

Lee, D S; Ahn, Y C; Eom, D W; Lee, S J

2016-10-01

Non-Hodgkin lymphoma involving the esophagus is very rare. Only a few cases have been reported in the English literature to date, and it accounts for less than 1% of all cases of gastrointestinal lymphoma. As this malignancy manifests as a submucosal tumor, pathological diagnosis by using a simple endoscopic biopsy alone is difficult. Therefore, surgical biopsy, endoscopic mucosal resection, and endoscopic ultrasound-guided fine-needle aspiration have been used in most cases. Herein, we report a case of esophageal mucosa-associated lymphoid tissue lymphoma in a 49-year-old man, which involved the use of a stacked forceps biopsy to obtain adequate samples for pathological analysis; the use of the stacked forceps biopsy method is unlike those used in previous cases. The patient received cyclophosphamide, vincristine, and prednisolone chemotherapy; he achieved a complete response. In addition, we review the literature relevant to this case. © 2015 International Society for Diseases of the Esophagus.

Stacking fault energies and slip in nanocrystalline metals.

PubMed

Van Swygenhoven, H; Derlet, P M; Frøseth, A G

2004-06-01

The search for deformation mechanisms in nanocrystalline metals has profited from the use of molecular dynamics calculations. These simulations have revealed two possible mechanisms; grain boundary accommodation, and intragranular slip involving dislocation emission and absorption at grain boundaries. But the precise nature of the slip mechanism is the subject of considerable debate, and the limitations of the simulation technique need to be taken into consideration. Here we show, using molecular dynamics simulations, that the nature of slip in nanocrystalline metals cannot be described in terms of the absolute value of the stacking fault energy-a correct interpretation requires the generalized stacking fault energy curve, involving both stable and unstable stacking fault energies. The molecular dynamics technique does not at present allow for the determination of rate-limiting processes, so the use of our calculations in the interpretation of experiments has to be undertaken with care.

Local adjacency metric dimension of sun graph and stacked book graph

NASA Astrophysics Data System (ADS)

Yulisda Badri, Alifiah; Darmaji

2018-03-01

A graph is a mathematical system consisting of a non-empty set of nodes and a set of empty sides. One of the topics to be studied in graph theory is the metric dimension. Application in the metric dimension is the navigation robot system on a path. Robot moves from one vertex to another vertex in the field by minimizing the errors that occur in translating the instructions (code) obtained from the vertices of that location. To move the robot must give different instructions (code). In order for the robot to move efficiently, the robot must be fast to translate the code of the nodes of the location it passes. so that the location vertex has a minimum distance. However, if the robot must move with the vertex location on a very large field, so the robot can not detect because the distance is too far.[6] In this case, the robot can determine its position by utilizing location vertices based on adjacency. The problem is to find the minimum cardinality of the required location vertex, and where to put, so that the robot can determine its location. The solution to this problem is the dimension of adjacency metric and adjacency metric bases. Rodrguez-Velzquez and Fernau combine the adjacency metric dimensions with local metric dimensions, thus becoming the local adjacency metric dimension. In the local adjacency metric dimension each vertex in the graph may have the same adjacency representation as the terms of the vertices. To obtain the local metric dimension of values in the graph of the Sun and the stacked book graph is used the construction method by considering the representation of each adjacent vertex of the graph.

2. RICE THRESHING MILL WITH CHIMNEY STACK. Fire burned on ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

2. RICE THRESHING MILL WITH CHIMNEY STACK. Fire burned on top of water pipe at base of chimney stack and steam went thru pipes to boiler on south side of wall. - Mansfield Plantation, Rice Threshing Mill, U.S. Route 701 vicinity, Georgetown, Georgetown County, SC

Evaluation of low wind modeling approaches for two tall-stack databases.

PubMed

Paine, Robert; Samani, Olga; Kaplan, Mary; Knipping, Eladio; Kumar, Naresh

2015-11-01

The performance of the AERMOD air dispersion model under low wind speed conditions, especially for applications with only one level of meteorological data and no direct turbulence measurements or vertical temperature gradient observations, is the focus of this study. The analysis documented in this paper addresses evaluations for low wind conditions involving tall stack releases for which multiple years of concurrent emissions, meteorological data, and monitoring data are available. AERMOD was tested on two field-study databases involving several SO2 monitors and hourly emissions data that had sub-hourly meteorological data (e.g., 10-min averages) available using several technical options: default mode, with various low wind speed beta options, and using the available sub-hourly meteorological data. These field study databases included (1) Mercer County, a North Dakota database featuring five SO2 monitors within 10 km of the Dakota Gasification Company's plant and the Antelope Valley Station power plant in an area of both flat and elevated terrain, and (2) a flat-terrain setting database with four SO2 monitors within 6 km of the Gibson Generating Station in southwest Indiana. Both sites featured regionally representative 10-m meteorological databases, with no significant terrain obstacles between the meteorological site and the emission sources. The low wind beta options show improvement in model performance helping to reduce some of the over-prediction biases currently present in AERMOD when run with regulatory default options. The overall findings with the low wind speed testing on these tall stack field-study databases indicate that AERMOD low wind speed options have a minor effect for flat terrain locations, but can have a significant effect for elevated terrain locations. The performance of AERMOD using low wind speed options leads to improved consistency of meteorological conditions associated with the highest observed and predicted concentration events. The

A novel application of dielectric stack actuators: a pumping micromixer

NASA Astrophysics Data System (ADS)

Solano-Arana, Susana; Klug, Florian; Mößinger, Holger; Förster-Zügel, Florentine; Schlaak, Helmut F.

2018-07-01

The fabrication of pumping micromixers as a novel application of dielectric stack actuators is proposed in this work. DEA micromixers can be valuable for medical and pharmaceutical applications, due to: firstly, the biocompatibility of the used materials (PDMS and graphite); secondly, the pumping is done with peristaltic movements, allowing only the walls of the channel to be in contact with the liquid, avoiding possible contamination from external parts; and thirdly, the low flow velocity in the micromixers required in many applications. The micromixer based on peristasltic movements will not only mix, but also pump the fluids in and out the device. The developed device is a hybrid micromixer: active, because it needs a voltage source to enhance the quality and speed of the mixing; and passive, with a similar shape to the well-known Y-type micromixers. The proposed micromixer is based on twelve stack actuators distributed in: two pumping chambers, consisting of four stack actuators in series; and a mixing chamber, made of four consecutive stack actuators with 30 layers per stack. The DEA micromixer is able to mix two solutions with a flow rate of 21.5 μl min–1 at the outlet, applying 1500 V at 10 Hz and actuating two actuators at a time.

Kissing loop interaction in adenine riboswitch: insights from umbrella sampling simulations.

PubMed

Di Palma, Francesco; Bottaro, Sandro; Bussi, Giovanni

2015-01-01

Riboswitches are cis-acting regulatory RNA elements prevalently located in the leader sequences of bacterial mRNA. An adenine sensing riboswitch cis-regulates adeninosine deaminase gene (add) in Vibrio vulnificus. The structural mechanism regulating its conformational changes upon ligand binding mostly remains to be elucidated. In this open framework it has been suggested that the ligand stabilizes the interaction of the distal "kissing loop" complex. Using accurate full-atom molecular dynamics with explicit solvent in combination with enhanced sampling techniques and advanced analysis methods it could be possible to provide a more detailed perspective on the formation of these tertiary contacts. In this work, we used umbrella sampling simulations to study the thermodynamics of the kissing loop complex in the presence and in the absence of the cognate ligand. We enforced the breaking/formation of the loop-loop interaction restraining the distance between the two loops. We also assessed the convergence of the results by using two alternative initialization protocols. A structural analysis was performed using a novel approach to analyze base contacts. Contacts between the two loops were progressively lost when larger inter-loop distances were enforced. Inter-loop Watson-Crick contacts survived at larger separation when compared with non-canonical pairing and stacking interactions. Intra-loop stacking contacts remained formed upon loop undocking. Our simulations qualitatively indicated that the ligand could stabilize the kissing loop complex. We also compared with previously published simulation studies. Kissing complex stabilization given by the ligand was compatible with available experimental data. However, the dependence of its value on the initialization protocol of the umbrella sampling simulations posed some questions on the quantitative interpretation of the results and called for better converged enhanced sampling simulations.

Breakdown of Shape Memory Effect in Bent Cu-Al-Ni Nanopillars: When Twin Boundaries Become Stacking Faults.

PubMed

Liu, Lifeng; Ding, Xiangdong; Sun, Jun; Li, Suzhi; Salje, Ekhard K H

2016-01-13

Bent Cu-Al-Ni nanopillars (diameters 90-750 nm) show a shape memory effect, SME, for diameters D > 300 nm. The SME and the associated twinning are located in a small deformed section of the nanopillar. Thick nanopillars (D > 300 nm) transform to austenite under heating, including the deformed region. Thin nanopillars (D < 130 nm) do not twin but generate highly disordered sequences of stacking faults in the deformed region. No SME occurs and heating converts only the undeformed regions into austenite. The defect-rich, deformed region remains in the martensite phase even after prolonged heating in the stability field of austenite. A complex mixture of twins and stacking faults was found for diameters 130 nm < D < 300 nm. The size effect of the SME in Cu-Al-Ni nanopillars consists of an approximately linear reduction of the SME between 300 and 130 nm when the SME completely vanishes for smaller diameters.

Nonsequential modeling of laser diode stacks using Zemax: simulation, optimization, and experimental validation.

PubMed

Coluccelli, Nicola

2010-08-01

Modeling a real laser diode stack based on Zemax ray tracing software that operates in a nonsequential mode is reported. The implementation of the model is presented together with the geometric and optical parameters to be adjusted to calibrate the model and to match the simulated intensity irradiance profiles with the experimental profiles. The calibration of the model is based on a near-field and a far-field measurement. The validation of the model has been accomplished by comparing the simulated and experimental transverse irradiance profiles at different positions along the caustic formed by a lens. Spot sizes and waist location are predicted with a maximum error below 6%.

76. General view looking east showing Rust Co. boiler stacks ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

76. General view looking east showing Rust Co. boiler stacks at left, Babcock & Wilcox type boiler stacks at right, Dovel horizontal gas washer in foreground, and No. 1 Furnace in distance. - Sloss-Sheffield Steel & Iron, First Avenue North Viaduct at Thirty-second Street, Birmingham, Jefferson County, AL

Stacking interactions of hydrogen-bridged rings – stronger than the stacking of benzene molecules.

PubMed

Blagojević, Jelena P; Zarić, Snežana D

2015-08-21

Analysis of crystal structures from the Cambridge Structural Database showed that 27% of all planar five-membered hydrogen-bridged rings, possessing only single bonds within the ring, form intermolecular stacking interactions. Interaction energy calculations show that interactions can be as strong as -4.9 kcal mol(-1), but dependent on ring structure.

User Driven Image Stacking for ODI Data and Beyond via a Highly Customizable Web Interface

NASA Astrophysics Data System (ADS)

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

2015-09-01

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.

Effect of stacking sequence on mechanical properties neem wood veneer plastic composites

NASA Astrophysics Data System (ADS)

Nagamadhu, M.; Kumar, G. C. Mohan; Jeyaraj, P.

2018-04-01

This study investigates the effect of wood veneer stacking sequence on mechanical properties of neem wood polymer composite (WPC) experimentally. Wood laminated samples were fabricated by conventional hand layup technique in a mold and cured under pressure at room temperature and then post cured at elevated temperature. Initially, the tensile, flexural, and impact test were conducted to understand the effect of weight fraction of fiber on mechanical properties. The mechanical properties have increased with the weight fraction of fiber. Moreover the stacking sequence of neem wood plays an important role. As it has a significant impact on the mechanical properties. The results indicated that 0°/0° WPC shows highest mechanical properties as compared to other sequences (90°/90°, 0°/90°, 45°/90°, 45°/45°). The Fourier Transform Infrared Spectroscopy (FTIR) Analysis were carried out to identify chemical compounds both in raw neem wood and neem wood epoxy composite. The microstructure raw/neat neem wood and the interfacial bonding characteristics of neem wood composite investigated using Scanning electron microscopy images.

Porous coolant tube holder for fuel cell stack

DOEpatents

Guthrie, Robin J.

1981-01-01

A coolant tube holder for a stack of fuel cells is a gas porous sheet of fibrous material adapted to be sandwiched between a cell electrode and a nonporous, gas impervious flat plate which separates adjacent cells. The porous holder has channels in one surface with coolant tubes disposed therein for carrying coolant through the stack. The gas impervious plate is preferably bonded to the opposite surface of the holder, and the channel depth is the full thickness of the holder.

Location Management in a Transport Layer Mobility Architecture

NASA Technical Reports Server (NTRS)

Eddy, Wesley M.; Ishac, Joseph

2005-01-01

Mobility architectures that place complexity in end nodes rather than in the network interior have many advantageous properties and are becoming popular research topics. Such architectures typically push mobility support into higher layers of the protocol stack than network layer approaches like Mobile IP. The literature is ripe with proposals to provide mobility services in the transport, session, and application layers. In this paper, we focus on a mobility architecture that makes the most significant changes to the transport layer. A common problem amongst all mobility protocols at various layers is location management, which entails translating some form of static identifier into a mobile node's dynamic location. Location management is required for mobile nodes to be able to provide globally-reachable services on-demand to other hosts. In this paper, we describe the challenges of location management in a transport layer mobility architecture, and discuss the advantages and disadvantages of various solutions proposed in the literature. Our conclusion is that, in principle, secure dynamic DNS is most desirable, although it may have current operational limitations. We note that this topic has room for further exploration, and we present this paper largely as a starting point for comparing possible solutions.

Reliability prediction of large fuel cell stack based on structure stress analysis

NASA Astrophysics Data System (ADS)

Liu, L. F.; Liu, B.; Wu, C. W.

2017-09-01

The aim of this paper is to improve the reliability of Proton Electrolyte Membrane Fuel Cell (PEMFC) stack by designing the clamping force and the thickness difference between the membrane electrode assembly (MEA) and the gasket. The stack reliability is directly determined by the component reliability, which is affected by the material property and contact stress. The component contact stress is a random variable because it is usually affected by many uncertain factors in the production and clamping process. We have investigated the influences of parameter variation coefficient on the probability distribution of contact stress using the equivalent stiffness model and the first-order second moment method. The optimal contact stress to make the component stay in the highest level reliability is obtained by the stress-strength interference model. To obtain the optimal contact stress between the contact components, the optimal thickness of the component and the stack clamping force are optimally designed. Finally, a detailed description is given how to design the MEA and gasket dimensions to obtain the highest stack reliability. This work can provide a valuable guidance in the design of stack structure for a high reliability of fuel cell stack.

Solid oxide fuel cell generator with removable modular fuel cell stack configurations

DOEpatents

Gillett, James E.; Dederer, Jeffrey T.; Zafred, Paolo R.; Collie, Jeffrey C.

1998-01-01

A high temperature solid oxide fuel cell generator produces electrical power from oxidation of hydrocarbon fuel gases such as natural gas, or conditioned fuel gases, such as carbon monoxide or hydrogen, with oxidant gases, such as air or oxygen. This electrochemical reaction occurs in a plurality of electrically connected solid oxide fuel cells bundled and arrayed in a unitary modular fuel cell stack disposed in a compartment in the generator container. The use of a unitary modular fuel cell stack in a generator is similar in concept to that of a removable battery. The fuel cell stack is provided in a pre-assembled self-supporting configuration where the fuel cells are mounted to a common structural base having surrounding side walls defining a chamber. Associated generator equipment may also be mounted to the fuel cell stack configuration to be integral therewith, such as a fuel and oxidant supply and distribution systems, fuel reformation systems, fuel cell support systems, combustion, exhaust and spent fuel recirculation systems, and the like. The pre-assembled self-supporting fuel cell stack arrangement allows for easier assembly, installation, maintenance, better structural support and longer life of the fuel cells contained in the fuel cell stack.

A Unit Cell Laboratory Experiment: Marbles, Magnets, and Stacking Arrangements

ERIC Educational Resources Information Center

Collins, David C.

2011-01-01

An undergraduate first-semester general chemistry laboratory experiment introducing face-centered, body-centered, and simple cubic unit cells is presented. Emphasis is placed on the stacking arrangement of solid spheres used to produce a particular unit cell. Marbles and spherical magnets are employed to prepare each stacking arrangement. Packing…

40 CFR 63.7296 - What emission limitations must I meet for battery stacks?

Code of Federal Regulations, 2010 CFR

2010-07-01

... for battery stacks? 63.7296 Section 63.7296 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY..., Quenching, and Battery Stacks Emission Limitations and Work Practice Standards § 63.7296 What emission limitations must I meet for battery stacks? You must not discharge to the atmosphere any emissions from any...

40 CFR 63.7296 - What emission limitations must I meet for battery stacks?

Code of Federal Regulations, 2013 CFR

2013-07-01

... for battery stacks? 63.7296 Section 63.7296 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY..., Quenching, and Battery Stacks Emission Limitations and Work Practice Standards § 63.7296 What emission limitations must I meet for battery stacks? You must not discharge to the atmosphere any emissions from any...

40 CFR 63.7296 - What emission limitations must I meet for battery stacks?

Code of Federal Regulations, 2011 CFR

2011-07-01

... for battery stacks? 63.7296 Section 63.7296 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY..., Quenching, and Battery Stacks Emission Limitations and Work Practice Standards § 63.7296 What emission limitations must I meet for battery stacks? You must not discharge to the atmosphere any emissions from any...

40 CFR 63.7296 - What emission limitations must I meet for battery stacks?

Code of Federal Regulations, 2012 CFR

2012-07-01

... for battery stacks? 63.7296 Section 63.7296 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY..., Quenching, and Battery Stacks Emission Limitations and Work Practice Standards § 63.7296 What emission limitations must I meet for battery stacks? You must not discharge to the atmosphere any emissions from any...

40 CFR 63.7296 - What emission limitations must I meet for battery stacks?

Code of Federal Regulations, 2014 CFR

2014-07-01

... for battery stacks? 63.7296 Section 63.7296 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY..., Quenching, and Battery Stacks Emission Limitations and Work Practice Standards § 63.7296 What emission limitations must I meet for battery stacks? You must not discharge to the atmosphere any emissions from any...

Sequence-Dependent Elasticity and Electrostatics of Single-Stranded DNA: Signatures of Base-Stacking

PubMed Central

McIntosh, Dustin B.; Duggan, Gina; Gouil, Quentin; Saleh, Omar A.

2014-01-01

Base-stacking is a key factor in the energetics that determines nucleic acid structure. We measure the tensile response of single-stranded DNA as a function of sequence and monovalent salt concentration to examine the effects of base-stacking on the mechanical and thermodynamic properties of single-stranded DNA. By comparing the elastic response of highly stacked poly(dA) and that of a polypyrimidine sequence with minimal stacking, we find that base-stacking in poly(dA) significantly enhances the polymer’s rigidity. The unstacking transition of poly(dA) at high force reveals that the intrinsic electrostatic tension on the molecule varies significantly more weakly on salt concentration than mean-field predictions. Further, we provide a model-independent estimate of the free energy difference between stacked poly(dA) and unstacked polypyrimidine, finding it to be ∼−0.25 kBT/base and nearly constant over three orders of magnitude in salt concentration. PMID:24507606

Atomic and electronic structure of trilayer graphene/SiC(0001): Evidence of Strong Dependence on Stacking Sequence and charge transfer.

PubMed

Pierucci, Debora; Brumme, Thomas; Girard, Jean-Christophe; Calandra, Matteo; Silly, Mathieu G; Sirotti, Fausto; Barbier, Antoine; Mauri, Francesco; Ouerghi, Abdelkarim

2016-09-15

The transport properties of few-layer graphene are the directly result of a peculiar band structure near the Dirac point. Here, for epitaxial graphene grown on SiC, we determine the effect of charge transfer from the SiC substrate on the local density of states (LDOS) of trilayer graphene using scaning tunneling microscopy/spectroscopy and angle resolved photoemission spectroscopy (ARPES). Different spectra are observed and are attributed to the existence of two stable polytypes of trilayer: Bernal (ABA) and rhomboedreal (ABC) staking. Their electronic properties strongly depend on the charge transfer from the substrate. We show that the LDOS of ABC stacking shows an additional peak located above the Dirac point in comparison with the LDOS of ABA stacking. The observed LDOS features, reflecting the underlying symmetry of the two polytypes, were reproduced by explicit calculations within density functional theory (DFT) including the charge transfer from the substrate. These findings demonstrate the pronounced effect of stacking order and charge transfer on the electronic structure of trilayer or few layer graphene. Our approach represents a significant step toward understand the electronic properties of graphene layer under electrical field.

Arbitrarily shaped dual-stacked patch antennas: A hybrid FEM simulation

NASA Technical Reports Server (NTRS)

Gong, Jian; Volakis, John L.

1995-01-01

A dual-stacked patch antenna is analyzed using a hybrid finite element - boundary integral (FE-BI) method. The metallic patches of the antenna are modeled as perfectly electric conducting (PEC) plates stacked on top of two different dielectric layers. The antenna patches may be of any shape and the lower patch is fed by a coaxial cable from underneath the ground plane or by an aperture coupled microstrip line. The ability of the hybrid FEM technique for the stacked patch antenna characterization will be stressed, and the EM coupling mechanism is also discussed with the aid of the computed near field patterns around the patches.

Fuel cell stack monitoring and system control

DOEpatents

Keskula, Donald H.; Doan, Tien M.; Clingerman, Bruce J.

2004-02-17

A control method for monitoring a fuel cell stack in a fuel cell system in which the actual voltage and actual current from the fuel cell stack are monitored. A preestablished relationship between voltage and current over the operating range of the fuel cell is established. A variance value between the actual measured voltage and the expected voltage magnitude for a given actual measured current is calculated and compared with a predetermined allowable variance. An output is generated if the calculated variance value exceeds the predetermined variance. The predetermined voltage-current for the fuel cell is symbolized as a polarization curve at given operating conditions of the fuel cell.

Note: O-ring stack system for electron gun alignment.

PubMed

Park, In-Yong; Cho, Boklae; Han, Cheolsu; Shin, Seungmin; Lee, Dongjun; Ahn, Sang Jung

2015-01-01

We present a reliable method for aligning an electron gun which consists of an electron source and lenses by controlling a stack of rubber O-rings in a vacuum condition. The beam direction angle is precisely tilted along two axes by adjusting the height difference of a stack of O-rings. In addition, the source position is shifted in each of three orthogonal directions. We show that the tilting angle and linear shift along the x and y axes as obtained from ten stacked O-rings are ±2.55° and ±2 mm, respectively. This study can easily be adapted to charged particle gun alignment and adjustments of the flange position in a vacuum, ensuring that its results can be useful with regard to electrical insulation between flanges with slight modifications.

40 CFR Appendix Vi to Part 266 - Stack Plume Rise

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 27 2011-07-01 2011-07-01 false Stack Plume Rise VI Appendix VI to Part 266 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) SOLID WASTES (CONTINUED... FACILITIES Pt. 266, App. VI Appendix VI to Part 266—Stack Plume Rise [Estimated Plume Rise (in Meters) Based...

40 CFR Appendix Vi to Part 266 - Stack Plume Rise

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 26 2010-07-01 2010-07-01 false Stack Plume Rise VI Appendix VI to Part 266 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) SOLID WASTES (CONTINUED... FACILITIES Pt. 266, App. VI Appendix VI to Part 266—Stack Plume Rise [Estimated Plume Rise (in Meters) Based...

RECENT ADVANCES IN HIGH TEMPERATURE ELECTROLYSIS AT IDAHO NATIONAL LABORATORY: STACK TESTS

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

X, Zhang; J. E. O'Brien; R. C. O'Brien

2012-07-01

High temperature steam electrolysis is a promising technology for efficient sustainable large-scale hydrogen production. Solid oxide electrolysis cells (SOECs) are able to utilize high temperature heat and electric power from advanced high-temperature nuclear reactors or renewable sources to generate carbon-free hydrogen at large scale. However, long term durability of SOECs needs to be improved significantly before commercialization of this technology. A degradation rate of 1%/khr or lower is proposed as a threshold value for commercialization of this technology. Solid oxide electrolysis stack tests have been conducted at Idaho National Laboratory to demonstrate recent improvements in long-term durability of SOECs. Electrolytesupportedmore » and electrode-supported SOEC stacks were provided by Ceramatec Inc., Materials and Systems Research Inc. (MSRI), and Saint Gobain Advanced Materials (St. Gobain), respectively for these tests. Long-term durability tests were generally operated for a duration of 1000 hours or more. Stack tests based on technology developed at Ceramatec and MSRI have shown significant improvement in durability in the electrolysis mode. Long-term degradation rates of 3.2%/khr and 4.6%/khr were observed for MSRI and Ceramatec stacks, respectively. One recent Ceramatec stack even showed negative degradation (performance improvement) over 1900 hours of operation. A three-cell short stack provided by St. Gobain, however, showed rapid degradation in the electrolysis mode. Improvements on electrode materials, interconnect coatings, and electrolyteelectrode interface microstructures contribute to better durability of SOEC stacks.« less

Glue-Free Stacked Luminescent Nanosheets Enable High-Resolution Ratiometric Temperature Mapping in Living Small Animals.

PubMed

Miyagawa, Takuya; Fujie, Toshinori; Ferdinandus; Vo Doan, Tat Thang; Sato, Hirotaka; Takeoka, Shinji

2016-12-14

In this paper, a microthermograph, temperature mapping with high spatial resolution, was established using luminescent molecules embedded ultrathin polymeric films (nanosheets), and demonstrated in a living small animal to map out and visualize temperature shift due to animal's muscular activity. Herein, we report super flexible and self-adhesive (no need of glue) nanothermosensor consisting of stacked two different polymeric nanosheets with thermosensitive (Eu-tris (dinaphthoylmethane)-bis-trioctylphosphine oxide: EuDT) and insensitive (Rhodamine 800) dyes being embedded. Such stacked nanosheets allow for the ratiometric thermometry, with which the undesired luminescence intensity shift due to focal drift or animal's z-axis displacement is eliminated and the desired intensity shift solely due to the temperature shift of the sample (living muscle) can be acquired. With the stacked luminescent nanosheets, we achieved the first-ever demonstration of video filming of chronologically changing temperature-shift distribution from the rest state to the active state of the muscles in the living animal. The polymer nanosheet engineering and in vivo microthermography presented in the paper are promising technologies to microscopically explore the heat production and heat transfer in living cells, tissues, and organisms with high spatial resolution beyond what existing thermometric technologies such as infrared thermography have ever achieved.

Bragg reflector based gate stack architecture for process integration of excimer laser annealing

NASA Astrophysics Data System (ADS)

Fortunato, G.; Mariucci, L.; Cuscunà, M.; Privitera, V.; La Magna, A.; Spinella, C.; Magrı, A.; Camalleri, M.; Salinas, D.; Simon, F.; Svensson, B.; Monakhov, E.

2006-12-01

An advanced gate stack structure, which incorporates a Bragg reflector, has been developed for the integration of excimer laser annealing into the power metal-oxide semiconductor (MOS) transistor fabrication process. This advanced gate structure effectively protects the gate stack from melting, thus solving the problem related to protrusion formation. By using this gate stack configuration, power MOS transistors were fabricated with improved electrical characteristics. The Bragg reflector based gate stack architecture can be applied to other device structures, such as scaled MOS transistors, thus extending the possibilities of process integration of excimer laser annealing.

Iridium Interfacial Stack (IRIS)

NASA Technical Reports Server (NTRS)

Spry, David James (Inventor)

2015-01-01

An iridium interfacial stack ("IrIS") and a method for producing the same are provided. The IrIS may include ordered layers of TaSi.sub.2, platinum, iridium, and platinum, and may be placed on top of a titanium layer and a silicon carbide layer. The IrIS may prevent, reduce, or mitigate against diffusion of elements such as oxygen, platinum, and gold through at least some of its layers.

Monolithic stacked blue light-emitting diodes with polarization-enhanced tunnel junctions.

PubMed

Kuo, Yen-Kuang; Shih, Ya-Hsuan; Chang, Jih-Yuan; Lai, Wei-Chih; Liu, Heng; Chen, Fang-Ming; Lee, Ming-Lun; Sheu, Jinn-Kong

2017-08-07

Monolithic stacked InGaN light-emitting diode (LED) connected by a polarization-enhanced GaN/AlN-based tunnel junction is demonstrated experimentally in this study. The typical stacked LEDs exhibit 80% enhancement in output power compared with conventional single LEDs because of the repeated use of electrons and holes for photon generation. The typical operation voltage of stacked LEDs is higher than twice the operation voltage of single LEDs. This high operation voltage can be attributed to the non-optimal tunneling junction in stacked LEDs. In addition to the analyses of experimental results, theoretical analysis of different schemes of tunnel junctions, including diagrams of energy bands, diagrams of electric fields, and current-voltage relation curves, are investigated using numerical simulation. The results shown in this paper demonstrate the feasibility in developing cost-effective and highly efficient tunnel-junction LEDs.

Device for equalizing molten electrolyte content in a fuel cell stack

DOEpatents

Smith, J.L.

1985-12-23

A device for equalizing the molten electrolyte content throughout the height of a fuel cell stack is disclosed. The device includes a passageway for electrolyte return with electrolyte wettable wicking material in the opposite end portions of the passageway. One end portion is disposed near the upper, negative end of the stack where electrolyte flooding occurs. The second end portion is placed near the lower, positive end of the stack where electrolyte is depleted. Heating means are provided at the upper portion of the passageway to increase electrolyte vapor pressure in the upper wicking material. The vapor is condensed in the lower passageway portion and conducted as molten electrolyte in the lower wick to the positive end face of the stack. An inlet is provided to inject a modifying gas into the passageway and thereby control the rate of electrolyte return.

Device for equalizing molten electrolyte content in a fuel cell stack

DOEpatents

Smith, James L.

1987-01-01

A device for equalizing the molten electrolyte content throughout the height of a fuel cell stack is disclosed. The device includes a passageway for electrolyte return with electrolyte wettable wicking material in the opposite end portions of the passageway. One end portion is disposed near the upper, negative end of the stack where electrolyte flooding occurs. The second end portion is placed near the lower, positive end of the stack where electrolyte is depleted. Heating means are provided at the upper portion of the passageway to increase electrolyte vapor pressure in the upper wicking material. The vapor is condensed in the lower passageway portion and conducted as molten electrolyte in the lower wick to the positive end face of the stack. An inlet is provided to inject a modifying gas into the passageway and thereby control the rate of electrolyte return.

The Effect of a Sport Stacking Intervention on Handwriting with Second Grade Students

ERIC Educational Resources Information Center

Li, Yuhua; Coleman, Diane; Ransdell, Mary; Coleman, Lyndsie; Irwin, Carol

2014-01-01

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…

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

PubMed

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

2006-01-23

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 the surface termination, the image can be transfered by the stack with very little deterioration of the resolution, that is the resolution of the final image is approximately the same as the resolution of the image formed behind one single photonic crystal slab.

Applying time-reverse-imaging techniques to locate individual low-frequency earthquakes on the San Andreas fault near Cholame, California

NASA Astrophysics Data System (ADS)

Horstmann, T.; Harrington, R. M.; Cochran, E.; Shelly, D. R.

2013-12-01

Observations of non-volcanic tremor have become ubiquitous in recent years. In spite of the abundance of observations, locating tremor remains a difficult task because of the lack of distinctive phase arrivals. Here we use time-reverse-imaging techniques that do not require identifying phase arrivals to locate individual low-frequency-earthquakes (LFEs) within tremor episodes on the San Andreas fault near Cholame, California. Time windows of 1.5-second duration containing LFEs are selected from continuously recorded waveforms of the local seismic network filtered between 1-5 Hz. We propagate the time-reversed seismic signal back through the subsurface using a staggered-grid finite-difference code. Assuming all rebroadcasted waveforms result from similar wave fields at the source origin, we search for wave field coherence in time and space to obtain the source location and origin time where the constructive interference is a maximum. We use an interpolated velocity model with a grid spacing of 100 m and a 5 ms time step to calculate the relative curl field energy amplitudes for each rebroadcasted seismogram every 50 ms for each grid point in the model. Finally, we perform a grid search for coherency in the curl field using a sliding time window, and taking the absolute value of the correlation coefficient to account for differences in radiation pattern. The highest median cross-correlation coefficient value over at a given grid point indicates the source location for the rebroadcasted event. Horizontal location errors based on the spatial extent of the highest 10% cross-correlation coefficient are on the order of 4 km, and vertical errors on the order of 3 km. Furthermore, a test of the method using earthquake data shows that the method produces an identical hypocentral location (within errors) as that obtained by standard ray-tracing methods. We also compare the event locations to a LFE catalog that locates the LFEs from stacked waveforms of repeated LFEs

Solid oxide fuel cell generator with removable modular fuel cell stack configurations

DOEpatents

Gillett, J.E.; Dederer, J.T.; Zafred, P.R.; Collie, J.C.

1998-04-21

A high temperature solid oxide fuel cell generator produces electrical power from oxidation of hydrocarbon fuel gases such as natural gas, or conditioned fuel gases, such as carbon monoxide or hydrogen, with oxidant gases, such as air or oxygen. This electrochemical reaction occurs in a plurality of electrically connected solid oxide fuel cells bundled and arrayed in a unitary modular fuel cell stack disposed in a compartment in the generator container. The use of a unitary modular fuel cell stack in a generator is similar in concept to that of a removable battery. The fuel cell stack is provided in a pre-assembled self-supporting configuration where the fuel cells are mounted to a common structural base having surrounding side walls defining a chamber. Associated generator equipment may also be mounted to the fuel cell stack configuration to be integral therewith, such as a fuel and oxidant supply and distribution systems, fuel reformation systems, fuel cell support systems, combustion, exhaust and spent fuel recirculation systems, and the like. The pre-assembled self-supporting fuel cell stack arrangement allows for easier assembly, installation, maintenance, better structural support and longer life of the fuel cells contained in the fuel cell stack. 8 figs.

Phonon Transport at the Interfaces of Vertically Stacked Graphene and Hexagonal Boron Nitride Heterostructures

DOE PAGES

Yan, Zhequan; Chen, Liang; Yoon, Mina; ...

2016-01-12

Hexagonal boron nitride (h-BN) is a substrate for graphene based nano-electronic devices. We investigate the ballistic phonon transport at the interface of vertically stacked graphene and h-BN heterostructures using first principles density functional theory and atomistic Green's function simulations considering the influence of lattice stacking. We compute the frequency and wave-vector dependent transmission function and observe distinct stacking-dependent phonon transmission features for the h-BN/graphene/h-BN sandwiched systems. We find that the in-plane acoustic modes have the dominant contributions to the phonon transmission and thermal boundary conductance (TBC) for the interfaces with the carbon atom located directly on top of the boronmore » atom (C–B matched) because of low interfacial spacing. The low interfacial spacing is a consequence of the differences in the effective atomic volume of N and B and the difference in the local electron density around N and B. For the structures with the carbon atom directly on top of the nitrogen atom (C–N matched), the spatial distance increases and the contribution of in-plane modes to the TBC decreases leading to higher contributions by out-of-plane acoustic modes. We find that the C–B matched interfaces have stronger phonon–phonon coupling than the C–N matched interfaces, which results in significantly higher TBC (more than 50%) in the C–B matched interface. The findings in this study will provide insights to understand the mechanism of phonon transport at h-BN/graphene/h-BN interfaces, to better explain the experimental observations and to engineer these interfaces to enhance heat dissipation in graphene based electronic devices.« less

The measurement of the stacking fault energy in copper, nickel and copper-nickel alloys

NASA Technical Reports Server (NTRS)

Leighly, H. P., Jr.

1982-01-01

The relationship of hydrogen solubility and the hydrogen embrittlement of high strength, high performance face centered cubic alloys to the stacking fault energy of the alloys was investigated. The stacking fault energy is inversely related to the distance between the two partial dislocations which are formed by the dissociation of a perfect dislocation. The two partial dislocations define a stacking fault in the crystal which offers a region for hydrogen segregation. The distance between the partial dislocations is measured by weak beam, dark field transmission electron microscopy. The stacking fault energy is calculated. Pure copper, pure nickel and copper-nickel single crystals are used to determine the stacking fault energy.

FPGA-Based Optical Cavity Phase Stabilization for Coherent Pulse Stacking

DOE PAGES

Xu, Yilun; Wilcox, Russell; Byrd, John; ...

2017-11-20

Coherent pulse stacking (CPS) is a new time-domain coherent addition technique that stacks several optical pulses into a single output pulse, enabling high pulse energy from fiber lasers. We develop a robust, scalable, and distributed digital control system with firmware and software integration for algorithms, to support the CPS application. We model CPS as a digital filter in the Z domain and implement a pulse-pattern-based cavity phase detection algorithm on an field-programmable gate array (FPGA). A two-stage (2+1 cavities) 15-pulse stacking system achieves an 11.0 peak-power enhancement factor. Each optical cavity is fed back at 1.5kHz, and stabilized at anmore » individually-prescribed round-trip phase with 0.7deg and 2.1deg rms phase errors for Stages 1 and 2, respectively. Optical cavity phase control with nanometer accuracy ensures 1.2% intensity stability of the stacked pulse over 12 h. The FPGA-based feedback control system can be scaled to large numbers of optical cavities.« less

FPGA-Based Optical Cavity Phase Stabilization for Coherent Pulse Stacking

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

Xu, Yilun; Wilcox, Russell; Byrd, John

Coherent pulse stacking (CPS) is a new time-domain coherent addition technique that stacks several optical pulses into a single output pulse, enabling high pulse energy from fiber lasers. We develop a robust, scalable, and distributed digital control system with firmware and software integration for algorithms, to support the CPS application. We model CPS as a digital filter in the Z domain and implement a pulse-pattern-based cavity phase detection algorithm on an field-programmable gate array (FPGA). A two-stage (2+1 cavities) 15-pulse stacking system achieves an 11.0 peak-power enhancement factor. Each optical cavity is fed back at 1.5kHz, and stabilized at anmore » individually-prescribed round-trip phase with 0.7deg and 2.1deg rms phase errors for Stages 1 and 2, respectively. Optical cavity phase control with nanometer accuracy ensures 1.2% intensity stability of the stacked pulse over 12 h. The FPGA-based feedback control system can be scaled to large numbers of optical cavities.« less

Note: O-ring stack system for electron gun alignment

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

Park, In-Yong; Cho, Boklae; Han, Cheolsu

We present a reliable method for aligning an electron gun which consists of an electron source and lenses by controlling a stack of rubber O-rings in a vacuum condition. The beam direction angle is precisely tilted along two axes by adjusting the height difference of a stack of O-rings. In addition, the source position is shifted in each of three orthogonal directions. We show that the tilting angle and linear shift along the x and y axes as obtained from ten stacked O-rings are ±2.55° and ±2 mm, respectively. This study can easily be adapted to charged particle gun alignmentmore » and adjustments of the flange position in a vacuum, ensuring that its results can be useful with regard to electrical insulation between flanges with slight modifications.« less

Thermo-Mechanical and Electrochemistry Modeling of Planar SOFC Stacks

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

Khaleel, Mohammad A.; Recknagle, Kurtis P.; Lin, Zijing

2002-12-01

Modeling activities at PNNL support design and development of modular SOFC systems. The SOFC stack modeling capability at PNNL has developed to a level at which planar stack designs can be compared and optimized for startup performance. Thermal-fluids and stress modeling is being performed to predict the transient temperature distribution and to determine the thermal stresses based on the temperature distribution. Current efforts also include the development of a model for calculating current density, cell voltage, and heat production in SOFC stacks with hydrogen or other fuels. The model includes the heat generation from both Joule heating and chemical reactions.more » It also accounts for species production and destruction via mass balance. The model is being linked to the finite element code MARC to allow for the evaluation of temperatures and stresses during steady state operations.« less

60. VIEW OF ROASTER ADDITION FROM WEST, LOCATION OF SYMONS ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

60. VIEW OF ROASTER ADDITION FROM WEST, LOCATION OF SYMONS 3 BY 8 FEET VIBRATING SCREEN. SHOWS BAKER COOLER WITH DUST COLLECTOR DUCT AND DISCHARGE CHUTE ON LEFT. THE 14 INCH BELT CONVEYOR WAS SUPPORTED ON TWO BENTS IN CENTER OF VIEW AS IT CONNECTED WITH THE BUCKET ELEVATOR/ORE BIN TOWER, WHICH IN TURN FED THE ROASTER (BEHIND). THE BASE OF THE ROASTER EXHAUST STACK IS AT THE UPPER RIGHT. - Bald Mountain Gold Mill, Nevada Gulch at head of False Bottom Creek, Lead, Lawrence County, SD

Graphanes: Sheets and stacking under pressure

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

Wen, Xiao-Dong; Hand, Louis; Labet, Vanessa

2011-04-26

Eight isomeric two-dimensional graphane sheets are found in a theoretical study. Four of these nets—two built on chair cyclohexanes, two on boat—are more stable thermodynamically than the isomeric benzene, or polyacetylene. Three-dimensional crystals are built up from the two-dimensional sheets, and their hypothetical behavior under pressure (up to 300 GPa) is explored. While the three-dimensional graphanes remain, as expected, insulating or semiconducting in this pressure range, there is a remarkable inversion in stability of the five crystals studied. Two stacking polytypes that are not the most stable at ambient pressure (one based on an unusual chair cyclohexane net, the othermore » on a boat) are significantly stabilized with increasing pressure relative to stackings of simple chair sheets. The explanation may lie in the balance on intra and intersheet contacts in the extended arrays.« less

The determination of the stacking fault energy in copper-nickel alloys

NASA Technical Reports Server (NTRS)

Leighly, H. P., Jr.

1982-01-01

Methods for determining the stacking fault energies of a series of nickel-copper alloys to gain an insight into the embrittling effect of hydrogen are evaluated. Plans for employing weak beam dark field electron microscopy to determine stacking fault energies are outlined.

Reducing the layer number of AB stacked multilayer graphene grown on nickel by annealing at low temperature.

PubMed

Velasco, J Marquez; Giamini, S A; Kelaidis, N; Tsipas, P; Tsoutsou, D; Kordas, G; Raptis, Y S; Boukos, N; Dimoulas, A

2015-10-09

Controlling the number of layers of graphene grown by chemical vapor deposition is crucial for large scale graphene application. We propose here an etching process of graphene which can be applied immediately after growth to control the number of layers. We use nickel (Ni) foil at high temperature (T = 900 °C) to produce multilayer-AB-stacked-graphene (MLG). The etching process is based on annealing the samples in a hydrogen/argon atmosphere at a relatively low temperature (T = 450 °C) inside the growth chamber. The extent of etching is mainly controlled by the annealing process duration. Using Raman spectroscopy we demonstrate that the number of layers was reduced, changing from MLG to few-layer-AB-stacked-graphene and in some cases to randomly oriented few layer graphene near the substrate. Furthermore, our method offers the significant advantage that it does not introduce defects in the samples, maintaining their original high quality. This fact and the low temperature our method uses make it a good candidate for controlling the layer number of already grown graphene in processes with a low thermal budget.

Stacking Fault Enriching the Electronic and Transport Properties of Few-Layer Phosphorenes and Black Phosphorus.

PubMed

Lei, Shuangying; Wang, Han; Huang, Lan; Sun, Yi-Yang; Zhang, Shengbai

2016-02-10

Interface engineering is critical for enriching the electronic and transport properties of two-dimensional materials. Here, we identify a new stacking, named Aδ, in few-layer phosphorenes (FLPs) and black phosphorus (BP) based on first-principles calculation. With its low formation energy, the Aδ stacking could exist in FLPs and BP as a stacking fault. The presence of the Aδ stacking fault induces a direct to indirect transition of the band gap in FLPs. It also affects the carrier mobilities by significantly increasing the carrier effective masses. More importantly, the Aδ stacking enables the fabrication of a whole spectrum of lateral junctions with all the type-I, II, and III alignments simply through the manipulation of the van der Waals stacking without resorting to any chemical modification. This is achieved by the widely tunable electron affinity and ionization potential of FLPs and BP with the Aδ stacking.

Low Cost Mars Sample Return Utilizing Dragon Lander Project

NASA Technical Reports Server (NTRS)

Stoker, Carol R.

2014-01-01

We studied a Mars sample return (MSR) mission that lands a SpaceX Dragon Capsule on Mars carrying sample collection hardware (an arm, drill, or small rover) and a spacecraft stack consisting of a Mars Ascent Vehicle (MAV) and Earth Return Vehicle (ERV) that collectively carry the sample container from Mars back to Earth orbit.

TI-59 PROGRAMMABLE CALCULATOR PROGRAMS FOR IN-STACK OPACITY, VENTURI SCRUBBERS, AND ELECTROSTATIC PRECIPITATORS

EPA Science Inventory

The report explains the basic concepts of in-stack opacity as measured by in-stack opacity monitors. Also included are calculator programs that model the performance of venturi scrubbers and electrostatic precipitators. The effect of particulate control devices on in-stack opacit...

Taxonomy of multi-focal nematode image stacks by a CNN based image fusion approach.

PubMed

Liu, Min; Wang, Xueping; Zhang, Hongzhong

2018-03-01

In the biomedical field, digital multi-focal images are very important for documentation and communication of specimen data, because the morphological information for a transparent specimen can be captured in form of a stack of high-quality images. Given biomedical image stacks containing multi-focal images, how to efficiently extract effective features from all layers to classify the image stacks is still an open question. We present to use a deep convolutional neural network (CNN) image fusion based multilinear approach for the taxonomy of multi-focal image stacks. A deep CNN based image fusion technique is used to combine relevant information of multi-focal images within a given image stack into a single image, which is more informative and complete than any single image in the given stack. Besides, multi-focal images within a stack are fused along 3 orthogonal directions, and multiple features extracted from the fused images along different directions are combined by canonical correlation analysis (CCA). Because multi-focal image stacks represent the effect of different factors - texture, shape, different instances within the same class and different classes of objects, we embed the deep CNN based image fusion method within a multilinear framework to propose an image fusion based multilinear classifier. The experimental results on nematode multi-focal image stacks demonstrated that the deep CNN image fusion based multilinear classifier can reach a higher classification rate (95.7%) than that by the previous multilinear based approach (88.7%), even we only use the texture feature instead of the combination of texture and shape features as in the previous work. The proposed deep CNN image fusion based multilinear approach shows great potential in building an automated nematode taxonomy system for nematologists. It is effective to classify multi-focal image stacks. Copyright © 2018 Elsevier B.V. All rights reserved.

Dynamic electrical reconfiguration for improved capacitor charging in microbial fuel cell stacks

NASA Astrophysics Data System (ADS)

Papaharalabos, George; Greenman, John; Stinchcombe, Andrew; Horsfield, Ian; Melhuish, Chris; Ieropoulos, Ioannis

2014-12-01

A microbial fuel cell (MFC) is a bioelectrochemical device that uses anaerobic bacteria to convert chemical energy locked in biomass into small amounts of electricity. One viable way of increasing energy extraction is by stacking multiple MFC units and exploiting the available electrical configurations for increasing the current or stepping up the voltage. The present study illustrates how a real-time electrical reconfiguration of MFCs in a stack, halves the time required to charge a capacitor (load) and achieves 35% higher current generation compared to a fixed electrical configuration. This is accomplished by progressively switching in-parallel elements to in-series units in the stack, thus maintaining an optimum potential difference between the stack and the capacitor, which in turn allows for a higher energy transfer.

Launch Vehicle Stage Adapter from Start to Stack

NASA Image and Video Library

2016-10-16

See how a test version of the launch vehicle stage adapter (LVSA) for NASA's new rocket, the Space Launch System, is designed, built and stacked in a test stand at the agency's Marshall Space Flight Center in Huntsville, Alabama. The LVSA was moved to a 65-foot-tall test stand Oct. 12 at Marshall. The test version LVSA will be stacked with other test pieces of the upper part of the SLS rocket and pushed, pulled and twisted as part of an upcoming test series to ensure each structure can withstand the incredible stresses of launch. The LVSA joins the core stage simulator, which was loaded into the test stand Sept. 21. The other three qualification articles and the Orion simulator will complete the stack later this fall. Testing is scheduled to begin in early 2017. SLS will be the world’s most powerful rocket, and with the Orion spacecraft, take astronauts to deep-space destinations, including the Journey to Mars. More information on the upcoming test series can be found here: http://go.nasa.gov/2dS8yXB

Regional benthic δ18O stacks with radiocarbon age models show Termination I onset differences of up to 4,000 years

NASA Astrophysics Data System (ADS)

Stern, J.; Lisiecki, L. E.

2013-12-01

The assumption of globally synchronous benthic foraminiferal δ18O changes is central to the development of global stacks (averages) and many other types of paleoclimate studies. However, a few well-dated individual benthic δ18O records have suggested the possibility of regional differences in the timing of Termination I (e.g., Skinner and Shackleton, 2005; Waelbroeck et al., 2011). These previous studies often used single core locations to describe vast areas of the ocean, so it has remained unclear whether the observed diachroneities are truly regional in scale or merely local. Here, we bridge the gap between global benthic δ18O stacks and individual records by presenting eight regional benthic δ18O stacks from 252 cores with age models based on a total of 776 planktonic foraminiferal radiocarbon dates from 61 of those cores. The earliest termination onset (beginning of deglacial benthic δ18O decrease) occurs in the intermediate South Atlantic stack at 18.5 kyr BP, shortly after the initial deglacial melting of Northern Hemisphere ice sheets. The latest termination onset occurs in the deep Indian stack at 14.5 kyr BP, coeval with the Bølling-Allerød warming. We find synchronous termination onsets at 17.5 kyr BP in the intermediate North Atlantic, deep North Atlantic, and deep South Atlantic, contrary to Waelbroeck et al. (2011). The deglacial benthic δ18O decrease in the deep Pacific lagged that of the deep Atlantic by an average of 1000 yr, with a maximum lag of ~1700 yr during the middle of the termination. The intermediate Pacific termination onset at 16.5 kyr BP happens 1000 yr after the deep Pacific termination onset at 17.5 kyr BP. The stacks extend beyond Termination I to ~40 kyr BP, allowing us to clarify and update certain aspects of millennial-scale benthic δ18O chronostratigraphy surrounding Heinrich events 2-3 and the transition into the Last Glacial Maximum. Our radiocarbon-dated regional benthic δ18O stacks demonstrate some of the

Classifier Subset Selection for the Stacked Generalization Method Applied to Emotion Recognition in Speech

PubMed Central

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

2015-01-01

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

Removing Sulphur Dioxide From Stack Gases

ERIC Educational Resources Information Center

Slack, A. V.

1973-01-01

Process types, process concepts, claims and counterclaims, cost factors, and the level of developed technology for sulfur dioxide control in stack gases are focused upon and evaluated. Wet and dry processes as well as recovery and throwaway processes are compared. (BL)

Stacking stability of MoS2 bilayer: An ab initio study

NASA Astrophysics Data System (ADS)

Tao, Peng; Guo, Huai-Hong; Yang, Teng; Zhang, Zhi-Dong

2014-10-01

The study of the stacking stability of bilayer MoS2 is essential since a bilayer has exhibited advantages over single layer MoS2 in many aspects for nanoelectronic applications. We explored the relative stability, optimal sliding path between different stacking orders of bilayer MoS2, and (especially) the effect of inter-layer stress, by combining first-principles density functional total energy calculations and the climbing-image nudge-elastic-band (CI-NEB) method. Among five typical stacking orders, which can be categorized into two kinds (I: AA, AB and II: AA', AB', A'B), we found that stacking orders with Mo and S superposing from both layers, such as AA' and AB, is more stable than the others. With smaller computational efforts than potential energy profile searching, we can study the effect of inter-layer stress on the stacking stability. Under isobaric condition, the sliding barrier increases by a few eV/(ucGPa) from AA' to AB', compared to 0.1 eV/(ucGPa) from AB to [AB]. Moreover, we found that interlayer compressive stress can help enhance the transport properties of AA'. This study can help understand why inter-layer stress by dielectric gating materials can be an effective means to improving MoS2 on nanoelectronic applications.

Temperature dependence of stacking faults in catalyst-free GaAs nanopillars.

PubMed

Shapiro, Joshua N; Lin, Andrew; Ratsch, Christian; Huffaker, D L

2013-11-29

Impressive opto-electronic devices and transistors have recently been fabricated from GaAs nanopillars grown by catalyst-free selective-area epitaxy, but this growth technique has always resulted in high densities of stacking faults. A stacking fault occurs when atoms on the growing (111) surface occupy the sites of a hexagonal-close-pack (hcp) lattice instead of the normal face-centered-cubic (fcc) lattice sites. When stacking faults occur consecutively, the crystal structure is locally wurtzite instead of zinc-blende, and the resulting band offsets are known to negatively impact device performance. Here we present experimental and theoretical evidence that indicate stacking fault formation is related to the size of the critical nucleus, which is temperature dependent. The difference in energy between the hcp and fcc orientation of small nuclei is computed using density-function theory. The minimum energy difference of 0.22 eV is calculated for a nucleus with 21 atoms, so the population of nuclei in the hcp orientation is expected to decrease as the nucleus grows larger. The experiment shows that stacking fault occurrence is dramatically reduced from 22% to 3% by raising the growth temperature from 730 to 790 ° C. These data are interpreted using classical nucleation theory which dictates a larger critical nucleus at higher growth temperature.

Reconfigurable Wideband Circularly Polarized Stacked Square Patch Antenna for Cognitive Radios

NASA Technical Reports Server (NTRS)

Barbosa Kortright, Miguel A.; Waldstein, Seth W.; Simons, Rainee N.

2017-01-01

An almost square patch, a square patch and a stacked square patch with corner truncation for circular polarization (CP) are researched and developed at X-band for cognitive radios. Experimental results indicate, first, that the impedance bandwidth of a CP almost square patch fed from the edge by a 50 ohm line is 1.70% and second, that of a CP square patch fed from the ground plane side by a surface launch connector is 1.87%. Third, the impedance bandwidth of a CP stacked square patch fed by a surface launch connector is 2.22%. The measured center frequency for the CP square patch fed by a surface launch connector without and with an identical stacked patch is 8.45 and 8.1017 GHz, respectively. By stacking a patch, separated by a fixed air gap of 0.254 mm, the center frequency is observed to shift by as much as 348.3 MHz. The shift in center frequency, brought about by the reconfiguring of the physical layer antenna, can be exploited in a cognitive system since it expands the usable frequency spectrum for software reconfiguration in the presence of interference. In addition, varying the fixed air gap in the stacked antenna geometry by increments of 0.254 mm further expands the usable frequency spectrum.

Moving object detection in top-view aerial videos improved by image stacking

NASA Astrophysics Data System (ADS)

Teutsch, Michael; Krüger, Wolfgang; Beyerer, Jürgen

2017-08-01

Image stacking is a well-known method that is used to improve the quality of images in video data. A set of consecutive images is aligned by applying image registration and warping. In the resulting image stack, each pixel has redundant information about its intensity value. This redundant information can be used to suppress image noise, resharpen blurry images, or even enhance the spatial image resolution as done in super-resolution. Small moving objects in the videos usually get blurred or distorted by image stacking and thus need to be handled explicitly. We use image stacking in an innovative way: image registration is applied to small moving objects only, and image warping blurs the stationary background that surrounds the moving objects. Our video data are coming from a small fixed-wing unmanned aerial vehicle (UAV) that acquires top-view gray-value images of urban scenes. Moving objects are mainly cars but also other vehicles such as motorcycles. The resulting images, after applying our proposed image stacking approach, are used to improve baseline algorithms for vehicle detection and segmentation. We improve precision and recall by up to 0.011, which corresponds to a reduction of the number of false positive and false negative detections by more than 3 per second. Furthermore, we show how our proposed image stacking approach can be implemented efficiently.

Modeling of a Stacked Power Module for Parasitic Inductance Extraction

DTIC Science & Technology

2017-09-15

issues of heat dissipation, reliability, and parasitic inductance. An improved packaging approach has been proposed to simultaneously address each of...and mechanical attachments. The power devices in the resulting module design are stacked between copper layers with an integrated heat sink. By...stacking devices, the module’s parasitic inductance should be reduced, with concurrent improvement of reliability and heat dissipation, in comparison to

X-ray versus infrared selection of distant galaxy clusters: A case study using the XMM-LSS and SpARCS cluster samples

NASA Astrophysics Data System (ADS)

Willis, J. P.; Ramos-Ceja, M. E.; Muzzin, A.; Pacaud, F.; Yee, H. K. C.; Wilson, G.

2018-04-01

We present a comparison of two samples of z > 0.8 galaxy clusters selected using different wavelength-dependent techniques and examine the physical differences between them. We consider 18 clusters from the X-ray selected XMM-LSS distant cluster survey and 92 clusters from the optical-MIR selected SpARCS cluster survey. Both samples are selected from the same approximately 9 square degree sky area and we examine them using common XMM-Newton, Spitzer-SWIRE and CFHT Legacy Survey data. Clusters from each sample are compared employing aperture measures of X-ray and MIR emission. We divide the SpARCS distant cluster sample into three sub-samples: a) X-ray bright, b) X-ray faint, MIR bright, and c) X-ray faint, MIR faint clusters. We determine that X-ray and MIR selected clusters display very similar surface brightness distributions of galaxy MIR light. In addition, the average location and amplitude of the galaxy red sequence as measured from stacked colour histograms is very similar in the X-ray and MIR-selected samples. The sub-sample of X-ray faint, MIR bright clusters displays a distribution of BCG-barycentre position offsets which extends to higher values than all other samples. This observation indicates that such clusters may exist in a more disturbed state compared to the majority of the distant cluster population sampled by XMM-LSS and SpARCS. This conclusion is supported by stacked X-ray images for the X-ray faint, MIR bright cluster sub-sample that display weak, centrally-concentrated X-ray emission, consistent with a population of growing clusters accreting from an extended envelope of material.

SLS Engine Section Test Article Moved for Stacking at Michoud

NASA Image and Video Library

2017-04-25

Stacking is underway for the Space Launch System core stage engine section structural qualification test article at NASA's Michoud Assembly Facility in New Orleans. The rocket's engine section is the bottom of the core stage and houses the four RS-25 engines. The engine section test article was moved to Michoud's Cell A in Building 110 for vertical stacking with hardware that simulates the rocket's liquid hydrogen tank, which is the fuel tank that joins to the engine section. Once stacked, the entire test article will load onto the barge Pegasus and ship to NASA's Marshall Space Flight Center in Huntsville, Alabama. There, it will be subjected to millions of pounds of force during testing to ensure the hardware can withstand the incredible stresses of launch.

Performance of air-cathode stacked microbial fuel cells systems for wastewater treatment and electricity production.

PubMed

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

2017-07-01

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.

Tests of a High Temperature Sample Conditioner for the Waste Treatment Plant LV-S2, LV-S3, HV-S3A and HV-S3B Exhaust Systems

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

Flaherty, Julia E.; Glissmeyer, John A.

2015-03-18

Tests were performed to evaluate a sample conditioning unit for stack monitoring at Hanford Tank Waste Treatment and Immobilization Plant (WTP) exhaust stacks with elevated air temperatures. The LV-S2, LV-S3, HV-S3A and HV-S3B exhaust stacks are expected to have elevated air temperature and dew point. At these emission points, exhaust temperatures are too high to deliver the air sample directly to the required stack monitoring equipment. As a result, a sample conditioning system is considered to cool and dry the air prior to its delivery to the stack monitoring system. The method proposed for the sample conditioning is a dilutionmore » system that will introduce cooler, dry air to the air sample stream. This method of sample conditioning is meant to reduce the sample temperature while avoiding condensation of moisture in the sample stream. An additional constraint is that the ANSI/HPS N13.1-1999 standard states that at least 50% of the 10 μm aerodynamic diameter (AD) particles present in the stack free stream must be delivered to the sample collector. In other words, depositional loss of particles should be limited to 50% in the sampling, transport, and conditioning systems. Based on estimates of particle penetration through the LV-S3 sampling system, the diluter should perform with about 80% penetration or better to ensure that the total sampling system passes the 50% or greater penetration criterion.« less

Influence factors of the inter-nanowire thermal contact resistance in the stacked nanowires

NASA Astrophysics Data System (ADS)

Wu, Dongxu; Huang, Congliang; Zhong, Jinxin; Lin, Zizhen

2018-05-01

The inter-nanowire thermal contact resistance is important for tuning the thermal conductivity of a nanocomposite for thermoelectric applications. In this paper, the stacked copper nanowires are applied for studying the thermal contact resistance. The stacked copper nanowires are firstly made by the cold-pressing method, and then the nanowire stacks are treated by sintering treatment. With the effect of the volumetric fraction of nanowires in the stack and the influence of the sintering-temperature on the thermal contact resistance discussed, results show that: The thermal conductivity of the 150-nm copper nanowires can be enlarged almost 2 times with the volumetric fraction increased from 32 to 56% because of the enlarged contact-area and contact number of a copper nanowire. When the sintering temperature increases from 293 to 673 K, the thermal conductivity of the stacked 300-nm nanowires could be enlarged almost 2.5 times by the sintering treatment, because of the improved lattice property of the contact zone. In conclusion, application of a high volumetric fraction or/and a sintering-treatment are effectivity to tune the inter-nanowire thermal contact resistance, and thus to tailor the thermal conductivity of a nanowire network or stack.

Interlayer orientation-dependent light absorption and emission in monolayer semiconductor stacks

PubMed Central

Heo, Hoseok; Sung, Ji Ho; Cha, Soonyoung; Jang, Bo-Gyu; Kim, Joo-Youn; Jin, Gangtae; Lee, Donghun; Ahn, Ji-Hoon; Lee, Myoung-Jae; Shim, Ji Hoon; Choi, Hyunyong; Jo, Moon-Ho

2015-01-01

Two-dimensional stacks of dissimilar hexagonal monolayers exhibit unusual electronic, photonic and photovoltaic responses that arise from substantial interlayer excitations. Interband excitation phenomena in individual hexagonal monolayer occur in states at band edges (valleys) in the hexagonal momentum space; therefore, low-energy interlayer excitation in the hexagonal monolayer stacks can be directed by the two-dimensional rotational degree of each monolayer crystal. However, this rotation-dependent excitation is largely unknown, due to lack in control over the relative monolayer rotations, thereby leading to momentum-mismatched interlayer excitations. Here, we report that light absorption and emission in MoS2/WS2 monolayer stacks can be tunable from indirect- to direct-gap transitions in both spectral and dynamic characteristics, when the constituent monolayer crystals are coherently stacked without in-plane rotation misfit. Our study suggests that the interlayer rotational attributes determine tunable interlayer excitation as a new set of basis for investigating optical phenomena in a two-dimensional hexagonal monolayer system. PMID:26099952

Simulation and resolution of voltage reversal in microbial fuel cell stack.

PubMed

Sugnaux, Marc; Savy, Cyrille; Cachelin, Christian Pierre; Hugenin, Gérald; Fischer, Fabian

2017-08-01

To understand the biotic and non-biotic contributions of voltage reversals in microbial fuel cell stacks (MFC) they were simulated with an electronic MFC-Stack mimic. The simulation was then compared with results from a real 3L triple MFC-Stack with shared anolyte. It showed that voltage reversals originate from the variability of biofilms, but also the external load plays a role. When similar biofilm properties were created on all anodes the likelihood of voltage reversals was largely reduced. Homogenous biofilms on all anodes were created by electrical circuit alternation and electrostimulation. Conversely, anolyte recirculation, or increased nutriment supply, postponed reversals and unfavourable voltage asymmetries on anodes persisted. In conclusion, voltage reversals are often a negative event but occur also in close to best MFC-Stack performance. They were manageable and this with a simplified MFC architecture in which multiple anodes share the same anolyte. Copyright © 2017 Elsevier Ltd. All rights reserved.

Process for 3D chip stacking

DOEpatents

Malba, V.

1998-11-10

A manufacturable process for fabricating electrical interconnects which extend from a top surface of an integrated circuit chip to a sidewall of the chip using laser pantography to pattern three dimensional interconnects. The electrical interconnects may be of an L-connect or L-shaped type. The process implements three dimensional (3D) stacking by moving the conventional bond or interface pads on a chip to the sidewall of the chip. Implementation of the process includes: (1) holding individual chips for batch processing, (2) depositing a dielectric passivation layer on the top and sidewalls of the chips, (3) opening vias in the dielectric, (4) forming the interconnects by laser pantography, and (5) removing the chips from the holding means. The process enables low cost manufacturing of chips with bond pads on the sidewalls, which enables stacking for increased performance, reduced space, and higher functional per unit volume. 3 figs.

Process for 3D chip stacking

DOEpatents

Malba, Vincent

1998-01-01

A manufacturable process for fabricating electrical interconnects which extend from a top surface of an integrated circuit chip to a sidewall of the chip using laser pantography to pattern three dimensional interconnects. The electrical interconnects may be of an L-connect or L-shaped type. The process implements three dimensional (3D) stacking by moving the conventional bond or interface pads on a chip to the sidewall of the chip. Implementation of the process includes: 1) holding individual chips for batch processing, 2) depositing a dielectric passivation layer on the top and sidewalls of the chips, 3) opening vias in the dielectric, 4) forming the interconnects by laser pantography, and 5) removing the chips from the holding means. The process enables low cost manufacturing of chips with bond pads on the sidewalls, which enables stacking for increased performance, reduced space, and higher functional per unit volume.

Multistage Force Amplification of Piezoelectric Stacks