Ultra-high efficiency moving wire combustion interface for on-line coupling of HPLC

PubMed Central

Thomas, Avi T.; Ognibene, Ted; Daley, Paul; Turteltaub, Ken; Radousky, Harry; Bench, Graham

2011-01-01

We describe a 100% efficient moving-wire interface for on-line coupling of high performance liquid chromatography which transmits 100% of carbon in non-volatile analytes to a CO2 gas accepting ion source. This interface accepts a flow of analyte in solvent, evaporates the solvent, combusts the remaining analyte, and directs the combustion products to the instrument of choice. Effluent is transferred to a periodically indented wire by a coherent jet to increase efficiency and maintain peak resolution. The combustion oven is plumbed such that gaseous combustion products are completely directed to an exit capillary, avoiding the loss of combustion products to the atmosphere. This system achieves the near complete transfer of analyte at HPLC flow rates up to 125 μL/min at a wire speed of 6 cm/s. This represents a 30x efficiency increase and 8x maximum wire loading compared to the spray transfer technique used in earlier moving wire interfaces. PMID:22004428

Electro-spray deposition of a mesoporous TiO2 charge collection layer: toward large scale and continuous production of high efficiency perovskite solar cells.

PubMed

Kim, Min-cheol; Kim, Byeong Jo; Yoon, Jungjin; Lee, Jin-wook; Suh, Dongchul; Park, Nam-gyu; Choi, Mansoo; Jung, Hyun Suk

2015-12-28

The spin-coating method, which is widely used for thin film device fabrication, is incapable of large-area deposition or being performed continuously. In perovskite hybrid solar cells using CH(3)NH(3)PbI(3) (MAPbI(3)), large-area deposition is essential for their potential use in mass production. Prior to replacing all the spin-coating process for fabrication of perovskite solar cells, herein, a mesoporous TiO(2) electron-collection layer is fabricated by using the electro-spray deposition (ESD) system. Moreover, impedance spectroscopy and transient photocurrent and photovoltage measurements reveal that the electro-sprayed mesoscopic TiO(2) film facilitates charge collection from the perovskite. The series resistance of the perovskite solar cell is also reduced owing to the highly porous nature of, and the low density of point defects in, the film. An optimized power conversion efficiency of 15.11% is achieved under an illumination of 1 sun; this efficiency is higher than that (13.67%) of the perovskite solar cell with the conventional spin-coated TiO(2) films. Furthermore, the large-area coating capability of the ESD process is verified through the coating of uniform 10 × 10 cm(2) TiO(2) films. This study clearly shows that ESD constitutes therefore a viable alternative for the fabrication of high-throughput, large-area perovskite solar cells.

Modification of TiO(2) nanotube surfaces by electro-spray deposition of amoxicillin combined with PLGA for bactericidal effects at surgical implantation sites.

PubMed

Lee, Jung-Hwan; Moon, Seung-Kyun; Kim, Kwang-Mahn; Kim, Kyoung-Nam

2013-01-01

To fabricate the antibiotic-releasing coatings on TiO(2) nanotube surfaces for wide applications of implant and bone plate in medical and dental surgery, the optimal deposition time of amoxicillin/PLGA solution simultaneously performing non-toxicity and a high bactericidal effect for preventing early implant failures was found. FE-SEM, ESD and FT-IR were used for confirming deposition of amoxicillin/PLGA on the TiO(2) surface. Also, the elution of amoxicillin/PLGA in a TiO(2) nanotube surface was measured by a UV-VIS spectrophotometer. The bactericidal effect of amoxicillin on the TiO(2) nanotube surface was evaluated by using Staphylococcus aureus (S. aureus). The cytotoxicity and cell proliferation were observed by WST assay using MC3T3-E1 osteoblast cells. The results indicated that the TiO(2) nanotube surface controlled by electro-spray deposition time with amoxicillin/PLGA solution could provide a high bactericidal effect against S. aureus by the bactericidal effect of amoxicillin, as well as good osteoblast cell proliferation at the TiO(2) nanotube surface without toxicity. This study used electro-spray deposition (ESD) methodology to obtain amoxicillin deposition in nanotube structures of TiO(2) and found the optimal deposition time of amoxicillin/PLGA solution simultaneously performing non-toxicity and a high bactericidal effect for preventing early implant failures.

Enhanced performance for the analysis of prostaglandins and thromboxanes by liquid chromatography-tandem mass spectrometry using a new atmospheric pressure ionization source.

PubMed

Lubin, Arnaud; Geerinckx, Suzy; Bajic, Steve; Cabooter, Deirdre; Augustijns, Patrick; Cuyckens, Filip; Vreeken, Rob J

2016-04-01

Eicosanoids, including prostaglandins and thromboxanes are lipid mediators synthetized from polyunsaturated fatty acids. They play an important role in cell signaling and are often reported as inflammatory markers. LC-MS/MS is the technique of choice for the analysis of these compounds, often in combination with advanced sample preparation techniques. Here we report a head to head comparison between an electrospray ionization source (ESI) and a new atmospheric pressure ionization source (UniSpray). The performance of both interfaces was evaluated in various matrices such as human plasma, pig colon and mouse colon. The UniSpray source shows an increase in method sensitivity up to a factor 5. Equivalent to better linearity and repeatability on various matrices as well as an increase in signal intensity were observed in comparison to ESI. Copyright © 2016 Elsevier B.V. All rights reserved.

Electro-convective versus electroosmotic instability in concentration polarization.

PubMed

Rubinstein, Isaak; Zaltzman, Boris

2007-10-31

Electro-convection is reviewed as a mechanism of mixing in the diffusion layer of a strong electrolyte adjacent to a charge-selective solid, such as an ion exchange (electrodialysis) membrane or an electrode. Two types of electro-convection in strong electrolytes may be distinguished: bulk electro-convection, due to the action of the electric field upon the residual space charge of a quasi-electro-neutral bulk solution, and convection induced by electroosmotic slip, due to electric forces acting in the thin electric double layer of either quasi-equilibrium or non-equilibrium type near the solid/liquid interface. According to recent studies, the latter appears to be the likely source of mixing in the diffusion layer, leading to 'over-limiting' conductance in electrodialysis. Electro-convection near a planar uniform charge selective solid/liquid interface sets on as a result of hydrodynamic instability of one-dimensional steady state electric conduction through such an interface. We compare the results of linear stability analysis obtained for instabilities of this kind appearing in the full electro-convective and limiting non-equilibrium electroosmotic formulations. The short- and long-wave aspects of these instabilities are discussed along with the wave number selection principles.

Spray algorithm without interface construction

NASA Astrophysics Data System (ADS)

Al-Kadhem Majhool, Ahmed Abed; Watkins, A. P.

2012-05-01

This research is aimed to create a new and robust family of convective schemes to capture the interface between the dispersed and the carrier phases in a spray without the need to build up the interface boundary. The selection of the Weighted Average Flux (WAF) scheme is due to this scheme being designed to deal with random flux scheme which is second-order accurate in space and time. The convective flux in each cell face utilizes the WAF scheme blended with Switching Technique for Advection and Capturing of Surfaces (STACS) scheme for high resolution flux limiters. In the next step, the high resolution scheme is blended with the WAF scheme to provide the sharpness and boundedness of the interface by using switching strategy. In this work, the Eulerian-Eulerian framework of non-reactive turbulent spray is set in terms of theoretical proposed methodology namely spray moments of drop size distribution, presented by Beck and Watkins [1]. The computational spray model avoids the need to segregate the local droplet number distribution into parcels of identical droplets. The proposed scheme is tested on capturing the spray edges in modelling hollow cone sprays without need to reconstruct two-phase interface. A test is made on simple comparison between TVD scheme and WAF scheme using the same flux limiter on convective flow hollow cone spray. Results show the WAF scheme gives a better prediction than TVD scheme. The only way to check the accuracy of the presented models is by evaluating the spray sheet thickness.

Simultaneous drug identification in urine of sexual assault victims by using liquid chromatography tandem mass spectrometry.

PubMed

Lee, Hei Hwa; Chen, Suen Chi; Lee, Jong Feng; Lin, Hsin Yu; Chen, Bai Hsiun

2018-01-01

According to domestic and international epidemiological investigation, the proportion of substance involved sexual assault has the trend of ascent. In the past, laboratory methods that investigated urine sample of the sexual assault victims was to screen with enzyme immunoassay and then confirmed with mass spectrometry. The objective of the study is to simultaneously identify abused drugs in 126 decoded urine samples of sexual assault victims by liquid chromatography tandem mass spectrometry. The instrument was operated in multiple-reaction monitoring with an electro-spray positive ionization mode. Chromatograms were separated with ACE5 C18 column on a gradient of acetonitrile. After liquid-liquid extraction, samples were passed through a 0.22μm PVDF filter before injection into the system. The limits of quantitation ranged from 0.2 to 10ng/mL. The precision (CV) results were below 12.9% (intraday) and 15.0% (interday). The intraday accuracy ranged from 84.8 to 121.0%, interday accuracy ranged from 72.0 to 117.3%. We found that 29 (23.0%) were positive for drugs. The most common drug identified is flunitrazepam (11.1%), followed by nimetazepam and ketamine (7.9%), some new psychoactive substances, such as 2C-B, mephedrone, methylone, PMA and PMMA were also identified. We identified abused drugs, benzodiazepines, and new psychoactive substances in urine of sexual assault victims by using liquid chromatography tandem mass spectrometry. Copyright © 2017 Elsevier B.V. All rights reserved.

Anomalous Epitaxial Growth in Thermally Sprayed YSZ and LZ Splats

NASA Astrophysics Data System (ADS)

Chen, Lin; Yang, Guan-Jun

2017-08-01

Thermally sprayed coatings are essentially layered materials, and lamellar interfaces are of great importance to coatings' performances. In the present study, to investigate the microstructures and defect features at thermally sprayed coating interfaces, homoepitaxial 8 mol.% yttria-stabilized zirconia (YSZ) and heteroepitaxial lanthanum zirconia (LZ) films were fabricated. The epitaxial interfaces were examined by high-resolution transmission electron microscope (HR-TEM) in detail. As a result, we report, for the first time, an anomalous incommensurate homoepitaxial growth with mismatch-induced dislocations in thermally sprayed YSZ splats to create a homointerface. We also find the anomalous heteroepitaxial growth in thermally sprayed LZ splats. The mechanism of the anomalous incommensurate growth was analyzed in detail. Essentially, it is a pseudo-heteroepitaxy because of the lattice mismatch between the film and the locally heated substrate, as the locally heated substrate is significantly strained by its cold surroundings. Moreover, the super-high-density dislocations were found in the interfacial region, which resulted from sufficient thermal fluctuations and extremely rapid cooling rates. Both the anomalous lattice mismatch and super-high-density dislocations lead to weak interfaces and violent cracking in thermally sprayed coatings. These were also the essential differences between the conventional and the present epitaxy by thermal spray technique.

Research on the Fatigue Flexural Performance of RC Beams Attacked by Salt Spray

NASA Astrophysics Data System (ADS)

Mao, Jiang-hong; Xu, Fang-yuan; Jin, Wei-liang; Zhang, Jun; Wu, Xi-xi; Chen, Cai-sheng

2018-04-01

The fatigue flexural performance of RC beams attacked by salt spray was studied. A testing method involving electro osmosis, electrical accelerated corrosion and salt spray was proposed. This corrosion process method effectively simulates real-world salt spray and fatigue loading exerted by RC components on sea bridges. Four RC beams that have different stress amplitudes were tested. It is found that deterioration by corrosion and fatigue loading reduces the fatigue life of the RC and decreases the ability of deformation. The fatigue life and deflection ability could be reduced by increasing the stress amplitude and the corrosion duration time. The test result demonstrates that this experimental method can couple corrosion deterioration and fatigue loading reasonably. This procedure may be applied to evaluate the fatigue life and concrete durability of RC components located in a natural salt spray environment.

Sol-gel coated ion sources for liquid chromatography-direct electron ionization mass spectrometry.

PubMed

Riboni, Nicolò; Magrini, Laura; Bianchi, Federica; Careri, Maria; Cappiello, Achille

2017-07-25

Advances in interfacing liquid chromatography and electron ionization mass spectrometry are presented. New ion source coatings synthesized by sol-gel technology were developed and tested as vaporization surfaces in terms of peak intensity, peak width and peak delay for the liquid chromatography-direct electron ionization mass spectrometry (Direct-EI) determination of environmental pollutants like polycyclic aromatic hydrocarbons and steroids. Silica-, titania-, and zirconia-based coatings were sprayed inside the stainless steel ion source and characterized in terms of thermal stability, film thickness and morphology. Negligible weight losses until 350-400 °C were observed for all the materials, with coating thicknesses in the 6 (±1)-11 (±2) μm range for optimal ionization process. The best performances in terms of both peak intensity and peak width were obtained by using the silica-based coating: the detection of the investigated compounds was feasible at low ng μl -1 levels with a good precision (RSD < 9% for polycyclic aromatic hydrocarbons and <11% for hormones). Copyright © 2017 Elsevier B.V. All rights reserved.

Characterization and Analysis of Paper Spray Ionization of Organic Compounds.

PubMed

Aliaga-Aguilar, Hugo

2018-01-01

Paper spray ionization has arisen relatively recently as a complement and alternative to electro- and nanospray ionization with silica capillaries. A majority of the work in the present literature focuses on the chemical aspect of paper spray. In order to study the physical and phenomenological facet of its implementation, we measured current and voltage distributions of Taylor cones. To study transport phenomena on filter paper, we addressed the behavior of large, sparingly soluble tetraalkylammonium ions, which are usually used as mobility standards, in paper spray. The variation of intensity with time of monomers and dimers of these ions was measured with a differential mobility analyzer and compared with that produced by contamination in the paper. At the same time, we evaluated the proficiency of different paper spray techniques for protein analysis using nano spray as a reference. Experiments suggest that Taylor cones in paper spray are subject to hysteresis, whereas transport phenomena in the porous substrate notably affects the ionization of the sample. Additionally, we observed that paper spray tends to favor lower charge states in proteins. Graphical Abstract.

Validation of Armadillo officinalis Dumèril, 1816 (Crustacea, Isopoda, Oniscidea) as a bioindicator: in vivo study of air benzene exposure.

PubMed

Agodi, A; Oliveri Conti, G; Barchitta, M; Quattrocchi, A; Lombardo, B M; Montesanto, G; Messina, G; Fiore, M; Ferrante, M

2015-04-01

This study tests the potential for using Armadillo officinalis as a bioindicator of exposure to and activation of benzene metabolic pathways using an in vivo model. A. officinalis specimens collected in a natural reserve were divided into a control and three test groups exposed to 2.00, 5.32 or 9.09 µg/m(3) benzene for 24h. Three independent tests were performed to assess model reproducibility. Animals were dissected to obtain three pooled tissue samples per group: hepatopancreas (HEP), other organs and tissues (OOT), and exoskeleton (EXO). Muconic acid (MA), S-phenylmercapturic acid (S-PMA), two human metabolites of benzene, and changes in mtDNA copy number, a human biomarker of benzene exposure, were determined in each sample; benzene was determined only in EXO. MA was measured by high-performance liquid chromatography (HPLC) with ultraviolet (UV) detection, S-PMA by triple quadrupole mass spectrometer liquid chromatography with electro spray ionization (LC-MS-ESI-TQD), mtDNA by real-time quantitative PCR and end-point PCR, and benzene by quadrupole mass spectrometer head-space gas chromatography (HSGC-MS). MA and S-PMA levels rose both in HEP and OOT; EXO exhibited increasing benzene concentrations; and mtDNA copy number rose in HEP but not in OOT samples. Overall, our findings demonstrate that A. officinalis is a sensitive bioindicator of air benzene exposure and show for the first time its ability to reproduce human metabolic dynamics. Copyright © 2015 Elsevier Inc. All rights reserved.

Determination of rutin in rat plasma by ultra performance liquid chromatography tandem mass spectrometry and application to pharmacokinetic study.

PubMed

Chen, Mengchun; Zhang, Xiaoqian; Wang, Hao; Lin, Baoli; Wang, Shuanghu; Hu, Guoxin

2015-04-01

A sensitive and rapid ultra performance liquid chromatography tandem mass spectrometry (UPLC-MS-MS) method for the determination of rutin in rat plasma was developed and validated. After addition of tolbutamide as internal standard (IS), protein precipitation by acetonitrile was used as sample preparation. The chromatographic separation was performed on an Acquity UPLC BEH C18 column (2.1 × 50 mm, 1.7 μm particle size), using acetonitrile-0.1% formic acid as the mobile phase with gradient elution, delivered at a flow-rate of 0.4 mL/min. Mass spectrometric analysis was performed using a XEVO TQD mass spectrometer coupled with an electro-spray ionization (ESI) source in the positive ion mode. The MRM transitions of m/z 610.91→302.98 and m/z 271.2→155.1 were used to quantify for rutin and tolbutamide, respectively. This assay method has been fully validated in terms of specificity, linearity, recovery and matrix effect, accuracy, precision and stability. Calibration curves were linear in the concentration ranges of 25-2000 ng/mL for rutin. Only 3 min was needed for an analytical run. This developed method was successfully used for determination of rutin in rat plasma for pharmacokinetic study. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Electrospraying and ultraviolet light curing of nanometer-thin polydimethylsiloxane membranes for low-voltage dielectric elastomer transducers

NASA Astrophysics Data System (ADS)

Osmani, Bekim; Töpper, Tino; Siketanc, Matej; Kovacs, Gabor M.; Müller, Bert

2017-04-01

Dielectric elastomer transducers (DETs) have attracted interest as actuators, sensors, and even as self-sensing actuators for applications in medicine, soft robotics, and microfluidics. To reach strains of more than 10 %, they currently require operating voltages of several hundred volts. In medical applications for artificial muscles, however, their operation is limited to a very few tens of volts, which implies high permittivity materials and thin-film structures. Such micro- or nanostructures can be prepared using electro-spraying, a cost-effective technique that allows upscaling using multiple nozzles for the fabrication of silicone films down to nanometer thickness. Deposition rates of several micrometers per hour have already been reached. It has been recently demonstrated that such membranes can be fabricated by electro-spraying and subsequent ultraviolet light irradiation. Herein, we introduce a relatively fast deposition of a dimethyl silicone copolymer fluid that contains mercaptopropyl side chains in addition to the methyl groups. Its elastic modulus was tuned with the irradiation dose of the 200 W Hg-Xe lamp. We also investigated the formation of elastomer films, using polymer concentrations in ethyl acetate of 1, 2, 5 and 10 vol%. After curing, the surface roughness was measured by means of atomic force microscopy. This instrument also enabled us to determine the average elastic modulus out of, for example, 400 nanoindentation measurements, using a spherical tip with a radius of 500 nm. The elastomer films were cured for a period of less than one minute, a speed that makes it feasible to combine electro-spraying and in situ curing in a single process step for fabricating low-voltage, multilayer DETs.

Microfluidic high performance liquid chromatography-chip hyphenation to inductively coupled plasma-mass spectrometry.

PubMed

Bishop, David P; Blanes, Lucas; Wilson, Alexander B; Wilbanks, Thor; Killeen, Kevin; Grimm, Rudolf; Wenzel, Ross; Major, Derek; Macka, Mirek; Clarke, David; Schmid, Robin; Cole, Nerida; Doble, Philip A

2017-05-12

The Agilent Chip Cube Interface is a microfluidic chip-based technology originally designed for nanospray molecular mass spectrometry in which the sample enrichment, nano-column, tubing, connectors and spray tip were integrated into a single biocompatible chip. Here we describe the hyphenation of the Chip Cube Interface to ICP-MS via modification of the standard HPLC chip design and a new total consumption nebuliser suitable for flow rates as low as 300nLmin -1 . The potential of the instrument to eliminate common nanoLC - ICP-MS shortcomings such as leaks, blockages and band-broadening was demonstrated via analysis of cyanocobalamin in equine plasma. The method was linear over three orders of magnitude with an r 2 of 0.9999, the peak area repeatability was 1.9% (n=7), and the detection limit was 14ngmL -1 . This novel configuration of the Chip Cube Interface coupled to ICP-MS is a suitable platform for the analysis of biomolecules associated with trace metals and speciation applications. Copyright © 2017 Elsevier B.V. All rights reserved.

Fabrication and modeling of bismuth titanate-PZT ceramic transducers for high temperature applications

NASA Astrophysics Data System (ADS)

Reinhardt, B.; Searfass, C.; Cyphers, R.; Sinding, K.; Pheil, C.; Tittmann, B.

2013-01-01

Utilization of a spray-on deposition technique of ferroelectric bismuth titanate (Bi4Ti3O12) composites has a competitive advantage to standard ultrasonic transducers. These can conform to curved surfaces, can operate at high temperature (Curie-Weiss temperature 685 °C) and are mechanically well-coupled to a substrate. However, an issue with many high temperature transducers such as bismuth titanate ceramics is that they have relatively low transduction efficiency, i.e. d33 is about 12-14 pC/F in Bi4Ti3O12 versus 650 pC/F in PZT-5H. It is a common conception that high-temperature capability comes at the cost of electro-mechanical coupling. It will be shown that the high temperature capability of bismuth-titanate-PZT composite transducers using the spray-on deposition technique previously developed, improves the electro-mechanical coupling while maintaining the high temperature performance and mechanical coupling. This material could provide advantages in harsh environments where high signal-to-noise ratios are needed.

Electro-mechanical probe positioning system for large volume plasma device

NASA Astrophysics Data System (ADS)

Sanyasi, A. K.; Sugandhi, R.; Srivastava, P. K.; Srivastav, Prabhakar; Awasthi, L. M.

2018-05-01

An automated electro-mechanical system for the positioning of plasma diagnostics has been designed and implemented in a Large Volume Plasma Device (LVPD). The system consists of 12 electro-mechanical assemblies, which are orchestrated using the Modbus communication protocol on 4-wire RS485 communications to meet the experimental requirements. Each assembly has a lead screw-based mechanical structure, Wilson feed-through-based vacuum interface, bipolar stepper motor, micro-controller-based stepper drive, and optical encoder for online positioning correction of probes. The novelty of the system lies in the orchestration of multiple drives on a single interface, fabrication and installation of the system for a large experimental device like the LVPD, in-house developed software, and adopted architectural practices. The paper discusses the design, description of hardware and software interfaces, and performance results in LVPD.

Electro-optic response in thin smectic C* film with chevron structures

NASA Astrophysics Data System (ADS)

Kudreyko, Aleksey A.; Migranov, Nail G.; Migranova, Dana N.

2016-12-01

The effects in electrostatic models of chevron surface-stabilized ferroelectric liquid crystals are investigated through numerical modeling. To study smectic C* director distribution within the cell, we consider two nonlinear approaches: the chevron interface does not interplay with the electric field; the electric field interplays with the chevron interface. The obtained results of the director field distribution are compared with the earlier linearized studies. We find that whether or not the electric field interplays with the chevron interface, the electro-optic response requires a generalized approach for its description. The threshold electric field, which is necessary for switching between two stable director states in the chevron cell is evaluated. This study suggests that, in many cases of practical interest, electro-optic response to the electric field and the threshold electric field can be precisely estimated. We argue that, beside being numerically efficient, our approach provides a convenient and a novel standpoint for looking at the electro-optic response problem. Project supported by the Russian Foundation for Basic Research (RFBR) (Grant Nos. 16-32-00043 and 14-02-97026).

Characterization and quantification of flavonoids and saponins in adzuki bean (Vigna angularis L.) by HPLC-DAD-ESI-MSn analysis.

PubMed

Liu, Rui; Cai, Zongwei; Xu, Baojun

2017-09-22

Bioactive activities of adzuki bean have been widely reported, however, the phytochemical information of adzuki bean is incomplete. The aim of this study was to characterize and quantify flavonoids and saponins in adzuki bean. High performance liquid chromatography with diode array detection and electro spray ionization-tandem multi-stage mass spectrometry (HPLC-DAD-ESI-MS n ) were applied to do qualitative and quantitative analyses. A total of 15 compounds from adzuki bean were identified by HPLC-DAD-ESI-MS n . Among 15 compounds identified, four flavonoids (catechin, vitexin-4″-O-glucoside, quercetin-3-O-glucoside, and quercetin-3-O-rutinoside) and six saponins (azukisaponin I, II, III, IV, V, and VI) in adzuki bean were further quantified by external calibration method using HPLC-MS with the program of time segment and extract ion chromatogram (EIC) analysis. Current qualitative and quantitative method based on HPLC and MS technique provides a scientific basis for in vitro and in vivo pharmacological study in the future. Graphical abstract Isolation and characterization of flavonoids and saponins from adzuki bean.

Simultaneous determination of triprolidine and pseudoephedrine in human plasma by liquid chromatography-ion trap mass spectrometry.

PubMed

Shakya, Ashok K; Arafat, Tawfiq A; Abuawwad, Ahmad N; Melhim, Munther; Al-Ghani, Jafar; Yacoub, Mahmoud J

2009-12-15

A highly efficient, selective and specific method for simultaneous quantitation of triprolidine and pseudoephedrine in human plasma by liquid chromatography-ion trap-tandem mass spectrometry coupled with electro spray ionization (LC-ESI-ion trap-tandem MS) has been validated and successfully applied to a clinical pharmacokinetic study. Both targeted compounds together with the internal standard (gabapentin) were extracted from the plasma by direct protein precipitation. Chromatographic separation was achieved on a C(18) ACE((R)) column (50.0mmx2.1mm, 5mum, Advance Chromatography Technologies, Aberdeen, UK), using an isocratic mobile phase, consisting of water, methanol and formic acid (55:45:0.5, v/v/v), at a flow-rate of 0.3mL/min. The transition monitored (positive mode) was m/z 279.1-->m/z 208.1 for triprolidine, m/z 165.9-->m/z 148.0 for pseudoephedrine and m/z 172.0-->m/z 154.0 for gabapentin (IS). This method had a chromatographic run time of 5.0min and a linear calibration curves ranged from 0.2 to 20.0ng/mL for triprolidine and 5.0-500.0ng/mL for pseudoephedrine. The within- and between-batch accuracy and precision (expressed as coefficient of variation, %C.V.) evaluated at four quality control levels were within 94.3-106.3% and 1.0-9.6% respectively. The mean recoveries of triprolidine, pseudoephedrine and gabapentin were 93.6, 76.3 and 82.0% respectively. Stability of triprolidine and pseudoephedrine was assessed under different storage conditions. The validated method was successfully employed for the bioequivalence study of triprolidine and pseudoephedrine formulation in twenty six volunteers under fasting conditions.

Electro-optic architecture (EOA) for sensors and actuators in aircraft propulsion systems

NASA Technical Reports Server (NTRS)

Glomb, W. L., Jr.

1989-01-01

Results of a study to design an optimal architecture for electro-optical sensing and control in advanced aircraft and space systems are described. The propulsion full authority digital Electronic Engine Control (EEC) was the focus for the study. The recommended architecture is an on-engine EEC which contains electro-optic interface circuits for fiber-optic sensors on the engine. Size and weight are reduced by multiplexing arrays of functionally similar sensors on a pair of optical fibers to common electro-optical interfaces. The architecture contains common, multiplex interfaces to seven sensor groups: (1) self luminous sensors; (2) high temperatures; (3) low temperatures; (4) speeds and flows; (5) vibration; (6) pressures; and (7) mechanical positions. Nine distinct fiber-optic sensor types were found to provide these sensing functions: (1) continuous wave (CW) intensity modulators; (2) time division multiplexing (TDM) digital optic codeplates; (3) time division multiplexing (TDM) analog self-referenced sensors; (4) wavelength division multiplexing (WDM) digital optic code plates; (5) wavelength division multiplexing (WDM) analog self-referenced intensity modulators; (6) analog optical spectral shifters; (7) self-luminous bodies; (8) coherent optical interferometers; and (9) remote electrical sensors. The report includes the results of a trade study including engine sensor requirements, environment, the basic sensor types, and relevant evaluation criteria. These figures of merit for the candidate interface types were calculated from the data supplied by leading manufacturers of fiber-optic sensors.

Plasma-sprayed titanium coating to polyetheretherketone improves the bone-implant interface.

PubMed

Walsh, William R; Bertollo, Nicky; Christou, Chrisopher; Schaffner, Dominik; Mobbs, Ralph J

2015-05-01

Rapid and stable fixation at the bone-implant interface would be regarded as one of the primary goals to achieve clinical efficacy, regardless of the surgical site. Although mechanical and physical properties of polyetheretherketone (PEEK) provide advantages for implant devices, the hydrophobic nature and the lack of direct bone contact remains a limitation. To examine the effects of a plasma-sprayed titanium coated PEEK on the mechanical and histologic properties at the bone-implant interface. A preclinical laboratory study. Polyetheretherketone and plasma-sprayed titanium coated PEEK implants (Ti-bond; Spinal Elements, Carlsbad, CA, USA) were placed in a line-to-line manner in cortical bone and in a press-fit manner in cancellous bone of adult sheep using an established ovine model. Shear strength was assessed in the cortical sites at 4 and 12 weeks, whereas histology was performed in cortical and cancellous sites at both time points. The titanium coating dramatically improved the shear strength at the bone-implant interface at 4 weeks and continued to improve with time compared with PEEK. Direct bone ongrowth in cancellous and cortical sites can be achieved using a plasma-sprayed titanium coating on PEEK. Direct bone to implant bonding can be achieved on PEEK in spite of its hydrophobic nature using a plasma-sprayed titanium coating. The plasma-sprayed titanium coating improved mechanical properties in the cortical sites and the histology in cortical and cancellous sites. Copyright © 2015 Elsevier Inc. All rights reserved.

Formation of high heat resistant coatings by using gas tunnel type plasma spraying.

PubMed

Kobayashi, A; Ando, Y; Kurokawa, K

2012-06-01

Zirconia sprayed coatings are widely used as thermal barrier coatings (TBC) for high temperature protection of metallic structures. However, their use in diesel engine combustion chamber components has the long run durability problems, such as the spallation at the interface between the coating and substrate due to the interface oxidation. Although zirconia coatings have been used in many applications, the interface spallation problem is still waiting to be solved under the critical conditions such as high temperature and high corrosion environment. The gas tunnel type plasma spraying developed by the author can make high quality ceramic coatings such as Al2O3 and ZrO2 coating compared to other plasma spraying method. A high hardness ceramic coating such as Al2O3 coating by the gas tunnel type plasma spraying, were investigated in the previous study. The Vickers hardness of the zirconia (ZrO2) coating increased with decreasing spraying distance, and a higher Vickers hardness of about Hv = 1200 could be obtained at a shorter spraying distance of L = 30 mm. ZrO2 coating formed has a high hardness layer at the surface side, which shows the graded functionality of hardness. In this study, ZrO2 composite coatings (TBCs) with Al2O3 were deposited on SS304 substrates by gas tunnel type plasma spraying. The performance such as the mechanical properties, thermal behavior and high temperature oxidation resistance of the functionally graded TBCs was investigated and discussed. The resultant coating samples with different spraying powders and thickness are compared in their corrosion resistance with coating thickness as variables. Corrosion potential was measured and analyzed corresponding to the microstructure of the coatings. High Heat Resistant Coatings, Gas Tunnel Type Plasma Spraying, Hardness,

Fabrication and Testing of Tapered Electro-spray Nozzles

DTIC Science & Technology

2012-09-01

4.2 Microclimate Issues .......................................................................................................20 5. Summary and...requirement, while using very low flow rates per nozzle to obtain small combustor geometries. 4.2 Microclimate One of the challenges with this...off the Taylor-cone. To determine if there is an influence of microclimate , the evaporation rate was calculated from the Langmuir equation 1, using

Microporous Ti implant compact coated with hydroxyapatite produced by electro-discharge-sintering and electrostatic-spray-deposition.

PubMed

Jo, Y J; Kim, Y H; Jo, Y H; Seong, J G; Chang, S Y; Van Tyne, C J; Lee, W H

2014-11-01

A single pulse of 1.5 kJ/0.7 g of atomized spherical Ti powder from 300 μF capacitor was applied to produce the porous-surfaced Ti implant compact by electro-discharge-sintering (EDS). A solid core surrounded by porous layer was self-consolidated by a discharge in the middle of the compact in 122 μsec. Average pore size, porosity, and compressive yield strength of EDS Ti compact were estimated to be about 68.2 μm, 25.5%, and 266.4 MPa, respectively. Coatings with hydroxyapatite (HAp) on the Ti compact were conducted by electrostatic-spray-deposition (ESD) method. As-deposited HAp coating was in the form of porous structure and consisted of HAp particles which were uniformly distributed on the Ti porous structure. By heat-treatment at 700 degrees C, HAp particles were agglomerated each other and melted to form a highly smooth and homogeneous HAp thin film consisted of equiaxed nano-scaled grains. Porous-surfaced Ti implant compacts coated with highly crystalline apatite phase were successfully obtained by using the EDS and ESD techniques.

Microstructure, Morphology, and Nanomechanical Properties Near Fine Holes Produced by Electro-Discharge Machining

NASA Astrophysics Data System (ADS)

Blau, P. J.; Howe, J. Y.; Coffey, D. W.; Trejo, R. M.; Kenik, E. D.; Jolly, B. C.; Yang, N.

2012-08-01

Fine holes in metal alloys are employed for many important technological purposes, including cooling and the precise atomization of liquids. For example, they play an important role in the metering and delivery of fuel to the combustion chambers in energy-efficient, low-emission diesel engines. Electro-discharge machining (EDM) is one process employed to produce such holes. Since the hole shape and bore morphology can affect fluid flow, and holes also represent structural discontinuities in the tips of the spray nozzles, it is important to understand the microstructures adjacent to these holes, the features of the hole walls, and the nanomechanical properties of the material that was in some manner altered by the EDM hole-making process. Several techniques were used to characterize the structure and properties of spray-holes in a commercial injector nozzle. These include scanning electron microscopy, cross sectioning and metallographic etching, bore surface roughness measurements by optical interferometry, scanning electron microscopy, and transmission electron microscopy of recast EDM layers extracted with the help of a focused ion beam.

Architecture for fiber-optic sensors and actuators in aircraft propulsion systems

NASA Technical Reports Server (NTRS)

Glomb, W. L., Jr.

1990-01-01

This paper describes a design for fiber-optic sensing and control in advanced aircraft Electronic Engine Control (EEC). The recommended architecture is an on-engine EEC which contains electro-optic interface circuits for fiber-optic sensors. Size and weight are reduced by multiplexing arrays of functionally similar sensors on a pairs of optical fibers to common electro-optical interfaces. The architecture contains interfaces to seven sensor groups. Nine distinct fiber-optic sensor types were found to provide the sensing functions. Analysis revealed no strong discriminator (except reliability of laser diodes and remote electronics) on which to base a selection of preferred common interface type. A hardware test program is recommended to assess the relative maturity of the technologies and to determine real performance in the engine environment.

Improving Erosion Resistance of Plasma-Sprayed Ceramic Coatings by Elevating the Deposition Temperature Based on the Critical Bonding Temperature

NASA Astrophysics Data System (ADS)

Yao, Shu-Wei; Yang, Guan-Jun; Li, Cheng-Xin; Li, Chang-Jiu

2018-01-01

Interlamellar bonding within plasma-sprayed coatings is one of the most important factors dominating the properties and performance of coatings. The interface bonding between lamellae significantly influences the erosion behavior of plasma-sprayed ceramic coatings. In this study, TiO2 and Al2O3 coatings with different microstructures were deposited at different deposition temperatures based on the critical bonding temperature concept. The erosion behavior of ceramic coatings was investigated. It was revealed that the coatings prepared at room temperature exhibit a typical lamellar structure with numerous unbonded interfaces, whereas the coatings deposited at the temperature above the critical bonding temperature present a dense structure with well-bonded interfaces. The erosion rate decreases sharply with the improvement of interlamellar bonding when the deposition temperature increases to the critical bonding temperature. In addition, the erosion mechanisms of ceramic coatings were examined. The unbonded interfaces in the conventional coatings act as pre-cracks accelerating the erosion of coatings. Thus, controlling interlamellar bonding formation based on the critical bonding temperature is an effective approach to improve the erosion resistance of plasma-sprayed ceramic coatings.

Microstructural inhomogeneity in plasma-sprayed hydroxyapatite coatings and effect of post-heat treatment

NASA Astrophysics Data System (ADS)

Lu, Yu-Peng; Xiao, Gui-Yong; Li, Shi-Tong; Sun, Rui-Xue; Li, Mu-Sen

2006-01-01

The microstructural inhomogeneity in the plasma-sprayed hydroxyapatite (HA) coatings was characterized by using electron probe microanalyser (EPMA). A simple and artful method was developed to detect the interface characteristics. All the samples for observation were ground and polished along the direction parallel to the coating surfaces. The BSE images directly and clearly showed the inhomogeneity in the as-sprayed coatings with the amorphous regions being bright gray and crystalline regions being dark gray. X-ray diffractometer (XRD) patterns indicated that after immersion in deionized water for 20 days, bone-like apatite and α-Ca 2P 2O 7 precipitated on the polished surfaces of the as-sprayed HA coatings. The post-heat treatment could eliminate the microstructural inhomogeneity in the coatings. Only β-Ca 2P 2O 7 precipitated on the surfaces of the heat-treated HA coatings. The immersed samples were re-polished till tiny substrate was bared to investigate the effect of immersion on interface. It was shown that the immersion decreased the cohesive strength of the as-sprayed coatings. There were more and broader cracks in the splats that came into contact with the substrate and amorphous phase increased toward the coating-substrate interface. Post-heat treatment was proved to reduce the peeling off of coating during re-polishing operation. It was proposed that the distributions of amorphous phase and cracks in as-sprayed coatings are detrimental to coating properties and should be modified through improving the plasma spraying processing.

Airborne Electro-Optical Sensor Simulation System. Final Report.

ERIC Educational Resources Information Center

Hayworth, Don

The total system capability, including all the special purpose and general purpose hardware comprising the Airborne Electro-Optical Sensor Simulation (AEOSS) System, is described. The functional relationship between hardware portions is described together with interface to the software portion of the computer image generation. Supporting rationale…

A novel analytical method for d-glucosamine quantification and its application in the analysis of chitosan degradation by a minimal enzyme cocktail.

PubMed

Mekasha, Sophanit; Toupalová, Hana; Linggadjaja, Eka; Tolani, Harish A; Anděra, Ladislav; Arntzen, Magnus Ø; Vaaje-Kolstad, Gustav; Eijsink, Vincent G H; Agger, Jane W

2016-10-04

Enzymatic depolymerization of chitosan, a β-(1,4)-linked polycationic polysaccharide composed of d-glucosamine (GlcN) and N-acetyl-d-glucosamine (GlcNAc) provides a possible route to the exploitation of chitin-rich biomass. Complete conversion of chitosan to mono-sugars requires the synergistic action of endo- and exo- chitosanases. In the present study we have developed an efficient and cost-effective chitosan-degrading enzyme cocktail containing only two enzymes, an endo-attacking bacterial chitosanase, ScCsn46A, from Streptomyces coelicolor, and an exo-attacking glucosamine specific β-glucosaminidase, Tk-Glm, from the archaeon Thermococcus kodakarensis KOD1. Moreover, we developed a fast, reliable quantitative method for analysis of GlcN using high performance anion exchange chromatography with pulsed amperometric detection (HPAEC-PAD). The sensitivity of this method is high and less than 50 pmol was easily detected, which is about 1000-fold better than the sensitivity of more commonly used detection methods based on refractive index. We also obtained qualitative insight into product development during the enzymatic degradation reaction by means of ElectroSpray Ionization-Mass Spectrometry (ESI-MS). Copyright © 2016 Elsevier Ltd. All rights reserved.

[Tissue-specific nucleoprotein complexes].

PubMed

Riadnova, I Iu; Shataeva, L K; Khavinson, V Kh

2000-01-01

A method of isolation of native nucleorprotein complexes from cattle cerebral cortex, thymus, and liver was developed. Compositions of these complexes were studied by means of gel-chromatography and ion-exchange chromatography. These preparations were shown to consist of several fractions of proteins and their complexes differ by molecular mass and electro-chemical properties. Native nucleoprotein complexes revealed high tissue specific activity, which was not species-specific.

Interfacial behavior of confined mesogens at smectic-C*-water boundary.

PubMed

Chandran, Achu; Khanna, P K; Haranath, D; Biradar, Ashok M

2018-02-01

In this paper, we have investigated the behavior of mesogens at smectic-C*-water interface confined in a liquid crystal (LC) cell with interfacial geometry. Polarized optical microscopy was used to probe the appearance of various smectic-C* domain patterns at water interface owing to the reorientation of mesogens. The undulated stripe domains observed at the air interface of smectic-C* meniscus vanished as the water entered into the smectic layers and focal conical domain patterns appeared at smectic-C*-water boundary. A spatially variable electro-optical switching of LC molecules was also observed outside the electrode area of the interfacial cell. The electrode region at the interface, as well as on the water side, was damaged upon application of an electric field of magnitude more than 150 kV/m. The change in dielectric parameters of mesogens was extensively studied at interface after evaporating the water. These studies give fundamental insights into smectic-C*-water interface and also will be helpful in fabricating better LC devices for electro-optical and sensing applications.

Interfacial behavior of confined mesogens at smectic-C*-water boundary

NASA Astrophysics Data System (ADS)

Chandran, Achu; Khanna, P. K.; Haranath, D.; Biradar, Ashok M.

2018-02-01

In this paper, we have investigated the behavior of mesogens at smectic-C*-water interface confined in a liquid crystal (LC) cell with interfacial geometry. Polarized optical microscopy was used to probe the appearance of various smectic-C* domain patterns at water interface owing to the reorientation of mesogens. The undulated stripe domains observed at the air interface of smectic-C* meniscus vanished as the water entered into the smectic layers and focal conical domain patterns appeared at smectic-C*-water boundary. A spatially variable electro-optical switching of LC molecules was also observed outside the electrode area of the interfacial cell. The electrode region at the interface, as well as on the water side, was damaged upon application of an electric field of magnitude more than 150 kV/m. The change in dielectric parameters of mesogens was extensively studied at interface after evaporating the water. These studies give fundamental insights into smectic-C*-water interface and also will be helpful in fabricating better LC devices for electro-optical and sensing applications.

Effect of Post-spray Shot Peening Treatment on the Corrosion Behavior of NiCr-Mo Coating by Plasma Spraying of the Shell-Core-Structured Powders

NASA Astrophysics Data System (ADS)

Tian, Jia-Jia; Wei, Ying-Kang; Li, Cheng-Xin; Yang, Guan-Jun; Li, Chang-Jiu

2018-01-01

Corrosion of metal plays a detrimental role in service lifetime of parts or systems. Therefore, coating a protective film which is fully dense and defects free on the base metal is an effective approach to protect the base metal from corrosion. In this study, a dense NiCr-20Mo coating with excellent lamellar interface bonding was deposited by plasma spraying of the novel shell-core-structured Mo-clad-NiCr powders, and then post-spray shot peening treatment by cold spraying of steel shots was applied to the plasma-sprayed NiCr-20Mo coating to obtain a fully dense coating through eliminating possibly existed pores and un-bonded interfaces within the NiCr-20Mo coating. Corrosion behaviors of the NiCr-20Mo coatings before and after shot peening were tested to investigate the effect of the post-spray shot peening on the corrosion behavior of the NiCr-20Mo coating. Results showed that a much dense and uniform plasma-sprayed NiCr-20Mo coating with perfect lamellar bonding at most of interfaces was deposited. However, the electrochemical tests revealed the existence of through-thickness pores in the as-plasma-sprayed NiCr-20Mo coating. Through the post-spray shot peening treatment, a completely dense top layer in the coating was formed, and with the increase in the shot peening intensity from one pass to three passes, the dense top layer became thicker from 100 μm to reach 300 μm of the whole coating thickness. Thus, a fully dense bulk-like coating was obtained. Corrosion test results showed that the dense coating layer resulting from densification of shot peening can act as an effective barrier coating to prevent the penetration of the corrosive medium and consequently protect the substrate from corrosion effectively. Therefore, a fully dense bulk-like NiCr-20Mo coating with excellent corrosion resistance can be achieved through the plasma spraying of Mo-clad-NiCr powders followed by appropriate post-spray shot peening treatment.

A numerical method for electro-kinetic flow with deformable fluid interfaces

NASA Astrophysics Data System (ADS)

Booty, Michael; Ma, Manman; Siegel, Michael

2013-11-01

We consider two-phase flow of ionic fluids whose motion is driven by an imposed electric field. At a fluid interface, a screening cloud of ions develops and forms an electro-chemical double layer or Debye layer. The imposed field acts on this induced charge distribution, resulting in a strong slip flow near the interface. We formulate a ``hybrid'' or multiscale numerical method in the thin Debye layer limit that incorporates an asymptotic analysis of the electrostatic potential and fluid dynamics in the Debye layer into a boundary integral solution of the full moving boundary problem. Results of the method are presented that show time-dependent deformation and steady state drop interface shapes when the timescale for charge-up of the Debye layer is either much less than or comparable to the timescale of the flow.

Optical study on thermal radiation energy of diesel spray combustion in a shock tube

NASA Astrophysics Data System (ADS)

Tsuboi, T.; Nagaya, K.; Ishii, K.

. A ``tailored'' interface shock tube was used to measure the thermal energy radiated from diesel-spray combustion. Experiments were performed in a steel shock tube with a seven m long low-pressure section filled with air and a six m long high-pressure section. Pre-compressed fuel was injected through a throttling nozzle into air behind a reflected shock wave. Monochromatic emissive powers and emissive powers of the whole IR-wavelengths were followed with IR-detectors set along the central axis of the tube. Time-dependent-radii, where soot particles radiate, were also determined. Results were : (1) the tailored interface shock tube could be applied to a study of diesel-spray combustion. (2) thermal radiation energy could be described well from the ignition delay of the fuel spray.

An interface tracking model for droplet electrocoalescence.

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

Erickson, Lindsay Crowl

This report describes an Early Career Laboratory Directed Research and Development (LDRD) project to develop an interface tracking model for droplet electrocoalescence. Many fluid-based technologies rely on electrical fields to control the motion of droplets, e.g. microfluidic devices for high-speed droplet sorting, solution separation for chemical detectors, and purification of biodiesel fuel. Precise control over droplets is crucial to these applications. However, electric fields can induce complex and unpredictable fluid dynamics. Recent experiments (Ristenpart et al. 2009) have demonstrated that oppositely charged droplets bounce rather than coalesce in the presence of strong electric fields. A transient aqueous bridge forms betweenmore » approaching drops prior to pinch-off. This observation applies to many types of fluids, but neither theory nor experiments have been able to offer a satisfactory explanation. Analytic hydrodynamic approximations for interfaces become invalid near coalescence, and therefore detailed numerical simulations are necessary. This is a computationally challenging problem that involves tracking a moving interface and solving complex multi-physics and multi-scale dynamics, which are beyond the capabilities of most state-of-the-art simulations. An interface-tracking model for electro-coalescence can provide a new perspective to a variety of applications in which interfacial physics are coupled with electrodynamics, including electro-osmosis, fabrication of microelectronics, fuel atomization, oil dehydration, nuclear waste reprocessing and solution separation for chemical detectors. We present a conformal decomposition finite element (CDFEM) interface-tracking method for the electrohydrodynamics of two-phase flow to demonstrate electro-coalescence. CDFEM is a sharp interface method that decomposes elements along fluid-fluid boundaries and uses a level set function to represent the interface.« less

40 CFR 63.2354 - What performance tests, design evaluations, and performance evaluations must I conduct?

Code of Federal Regulations, 2011 CFR

2011-07-01

... of Gaseous Organic Compounds by Direct Interface Gas Chromatography-Mass Spectrometry (incorporated... Method for Determination of Gaseous Organic Compounds by Direct Interface Gas Chromatography-Mass... Interface Gas Chromatography-Mass Spectrometry (incorporated by reference, see § 63.14),; or (B) For target...

A sharp, robust, and quantitative method by liquid chromatography tandem mass spectrometry for the measurement of EAD for acute radiation syndrome and its application.

PubMed

Zhang, Yiwei; Li, Jian; Meng, Zhiyun; Zhu, Xiaoxia; Gan, Hui; Gu, Ruolan; Wu, Zhuona; Zheng, Ying; Wei, Jinbin; Dou, Guifang

2017-06-15

17-Ethinyl-3,17-dihydroxyandrost-5-ene (EAD) is an agent designed for the treatment of acute radiation syndrome (ARS). Given its vital role played in the prevention and mitigation of ARS, the development of a sharp, sensitive and robust liquid chromatography tandem mass spectrometry (LC-MS/MS) method to monitor the metabolism of EAD in vivo was crucial. A new method was constructed and validated for the determination of EAD with the internal standard of androst-5-ene-3β,17β-diol (5-AED). The blood samples were precipitated with methanol, centrifuged, from which the supernatant was separated on UPLC with C18 column and eluted in gradient with acetonitrile and Milli-Q water both containing 0.1% formic acid (FA). Quantification was performed by a triple quadrupole mass spectrometer with electro spray ionization (ESI) in multiple reactive monitoring (MRM) positive mode. A good linearity was obtained with R>0.99 for EAD within its calibration range from 5 to 1000ngmL -1 with a lowest limit of quantification (LLOQ) of 5ngmL -1 . Inter- and intra-day accuracy and precision of three levels of quality control (QC) samples were within the range of 15%, while the LLOQ was within 20%. Samples were stable under the circumstances of the experiments. The method was simple, accurate and robust applied to determine the concentrations of EAD in Wistar rat after a single administration of EAD orally at the dose of 100mgkg -1 . Copyright © 2017 Elsevier B.V. All rights reserved.

Development of a liquid chromatography–tandem mass spectrometry method for the determination of sulfonamides, trimethoprim and dapsone in honey and validation according to Commission Decision 2002/657/EC for banned compounds [corrected].

PubMed

Economou, Anastasios; Petraki, Olympia; Tsipi, Despina; Botitsi, Eleni

2012-08-15

This work reports a sensitive liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for identification and quantification of seven sulfonamides, trimethoprim and dapsone in honey. The method is based on a solid-phase extraction (SPE) step of the target analytes with Oasis HLB cartridges after acidic hydrolysis of the honey sample to liberate the sugar-bound sulfonamides. Analysis was performed using liquid chromatography-tandem mass spectrometry (LC-MS/MS) in the positive electro-spray ionization (ESI) mode with two different isotopically labeled internal standards with the view to improve the quantitative performance of the method. The method validation has been performed according to the Commission Decision 2002/657/EC; the average recoveries, measured at three concentration levels (1.5, 2.5 and 5.0 μg kg(-1)), have been estimated in the range 70 to 106% while the respective % relative standard deviations of the within-laboratory reproducibility ranged from 6 to 18%. Mean values of the expanded uncertainties calculated were in the range 22-41% at the 99% confidence level. Decision limit (CCα) and detection capability (CCβ) values were in the ranges 0.4-0.9 and 0.7-1.4 μg kg(-1), respectively. Matrix effects have been investigated demonstrating a moderate signal suppression/enhancement for most of the target compounds. The method described has been successfully applied to the analysis of honey samples; sulfamethoxazole, sulfathiazole and trimethoprim were detected in some cases. Copyright © 2012 Elsevier B.V. All rights reserved.

Microstructures of plasma-sprayed hydroxyapatite-coated Ti-6Al-4V dental implants.

PubMed

Tufekci, E; Brantley, W A; Mitchell, J C; McGlumphy, E A

1997-01-01

The purpose of this study was to investigate the microstructure of plasma-sprayed hydroxyapatite coatings and the elemental composition near the coating-substrate interface for two commercial implants, using the scanning electron microscope. Both coating surfaces and cross-sectioned specimens were examined. The results indicated that while the surface microstructures of both implants were consistent with the plasma-spraying process, the scale of the constituents was much finer for one product. In cross-section, both coatings exhibited minimal porosity and intimate contact with the titanium alloy substrate. It was found that limited interdiffusion of titanium and calcium occurred near the interface.

In situ identification of high-performance thin-layer chromatography spots by fourier transform surface-enhanced Raman scattering

NASA Astrophysics Data System (ADS)

Koglin, Eckhardt; Kramer, Hella; Sawatski, Juergen; Lehner, Carolin; Hellman, Janice L.

1994-01-01

FT-SERS has been used to identify samples supported on high-performance thin-layer chromatography plates. The TLC plates were sprayed with colloidal silver solutions which resulted in enhancement of the FT-Raman scattering of these biologically and environmentally important compounds.

High bandwidth electro-optic technology for intersatellite optical communications

NASA Technical Reports Server (NTRS)

Krainak, Michael A.

1992-01-01

The research and development of electronic and electro-optic components for geosynchronous and low earth orbiting satellite optical high bandwidth communications at the NASA-Goddard Space Flight Center is reviewed. Intersatellite optical communications retains a strong reliance on microwave circuit technology in several areas - the microwave to optical interface, the laser transmitter modulation driver and the optical receiver. A microwave to optical interface is described requiring high bandwidth electronic downconverters and demodulators. Electrical bandwidth and current drive requirements for the laser modulation driver for three laser alternatives are discussed. Bandwidth and noise requirements are presented for optical receiver architectures.

Resolving Overlimiting Current Mechanisms in Microchannel-Nanochannel Interface Devices

NASA Astrophysics Data System (ADS)

Yossifon, Gilad; Leibowitz, Neta; Liel, Uri; Schiffbauer, Jarrod; Park, Sinwook

2015-11-01

We present results demonstrating the space charge-mediated transition between classical, diffusion-limited current and surface-conduction dominant over-limiting currents in a shallow micro-nanochannel device. The extended space charge layer develops at the depleted micro-nanochannel entrance at high current and is correlated with a distinctive maximum in the dc resistance. Experimental results for a shallow surface-conduction dominated system are compared with theoretical models, allowing estimates of the effective surface charge at high voltage to be obtained. Further, we extend the study to microchannels of moderate to large depths where the role of various electro-convection mechanisms becomes dominant. In particular, electro-osmotic of the second kind and electro-osmotic instability (EOI) which competes each other at geometrically heterogeneous (e.g. undulated nanoslot interface, array of nanoslots) nanoslot devices. Also, these effects are also shown to be strongly modulated by the non-ideal permselectivity of the nanochannel.

Investigation of applicability of Electro-Fenton method for the mineralization of naphthol blue black in water.

PubMed

Özcan, Ayça Atılır; Özcan, Ali

2018-07-01

In this study, mineralization and color removal performance of electro-Fenton method were examined in water containing naphthol blue black (NBB), a diazo dye. NBB was totally converted to intermediate species in a 15-min electrolysis at 60 mA, but complete de-colorization took 180 min. A very high oxidation rate constant ((3.35 ± 0.21) x 10 10  M -1 s -1 ) was obtained for NBB, showing its high reactivity towards hydroxyl radicals. A very high total organic carbon (TOC) removal value (45.23 mg L -1 ) was obtained in the first 60 min of the electro-Fenton treatment of an aqueous solution of NBB (0.25 mM) at 300 mA, indicating the mineralization efficiency of the electro-Fenton method. Mineralization current efficiency values obtained at 300 mA gradually decreased from 24.18% to 4.47% with the electrolysis time, indicating the presence of highly parasitic reactions. Gas chromatography-mass spectrometry analyses revealed that the cleavage of azo bonds of NBB led to formation of different aromatic and aliphatic oxidation intermediates. Ion chromatography analysis showed that ammonium, nitrate and sulfate were the mineralization end-products. The concentration of sulfate ion reached to its quantitative value at the 4th h of electrolysis. On the other hand, the total concentration of ammonium and nitrate ions reached to only 61% of the stoichiometric amount of initial nitrogen after a 7 h electrolysis. Finally, it can be said that the electro-Fenton method is a suitable and efficient method for the removal of NBB and its intermediates from water. Copyright © 2018 Elsevier Ltd. All rights reserved.

Probing electronic and vibrational properties at the electrochemical interface using SFG spectroscopy: Methanol electro-oxidation on Pt(1 1 0)

NASA Astrophysics Data System (ADS)

Vidal, F.; Busson, B.; Tadjeddine, A.

2005-02-01

We report the study of methanol electro-oxidation on Pt(1 1 0) using infrared-visible sum-frequency generation (SFG) vibrational spectroscopy. The use of this technique enables to probe the vibrational and electronic properties of the interface simultaneously in situ. We have investigated the vibrational properties of the interface in the CO ads internal stretch spectral region (1700-2150 cm -1) over a wide range of potentials. The analysis of the evolution of the C-O stretch line shape, which is related to the interference between the vibrational and electronic parts of the non-linear response, with the potential allows us to show that the onset of bulk methanol oxidation corresponds to the transition from a negatively to a positively charged surface.

Using Eye Movement to Control a Computer: A Design for a Lightweight Electro-Oculogram Electrode Array and Computer Interface

PubMed Central

Iáñez, Eduardo; Azorin, Jose M.; Perez-Vidal, Carlos

2013-01-01

This paper describes a human-computer interface based on electro-oculography (EOG) that allows interaction with a computer using eye movement. The EOG registers the movement of the eye by measuring, through electrodes, the difference of potential between the cornea and the retina. A new pair of EOG glasses have been designed to improve the user's comfort and to remove the manual procedure of placing the EOG electrodes around the user's eye. The interface, which includes the EOG electrodes, uses a new processing algorithm that is able to detect the gaze direction and the blink of the eyes from the EOG signals. The system reliably enabled subjects to control the movement of a dot on a video screen. PMID:23843986

Plasma-sprayed CaTiSiO5 ceramic coating on Ti-6Al-4V with excellent bonding strength, stability and cellular bioactivity.

PubMed

Wu, Chengtie; Ramaswamy, Yogambha; Liu, Xuanyong; Wang, Guocheng; Zreiqat, Hala

2009-02-06

Novel Ca-Si-Ti-based sphene (CaTiSiO5) ceramics possess excellent chemical stability and cytocompatibility. The aim of this study was to prepare sphene coating on titanium alloy (Ti-6Al-4V) for orthopaedic applications using the plasma spray method. The phase composition, surface and interface microstructure, coating thickness, surface roughness and bonding strength of the plasma-sprayed sphene coating were analysed using X-ray diffraction, scanning electron microscopy, atomic force microscopy and the standard mechanical testing of the American Society for Testing and Materials, respectively. The results indicated that sphene coating was obtained with a uniform and dense microstructure at the interface of the Ti-6Al-4V surface and the thickness and surface roughness of the coating were approximately 150 and 10 microm, respectively. Plasma-sprayed sphene coating on Ti-6Al-4V possessed a significantly improved bonding strength and chemical stability compared with plasma-sprayed hydroxyapatite (HAp) coating. Plasma-sprayed sphene coating supported human osteoblast-like cell (HOB) attachment and significantly enhanced HOB proliferation and differentiation compared with plasma-sprayed HAp coating and uncoated Ti-6Al-4V. Taken together, plasma-sprayed sphene coating on Ti-6Al-4V possessed excellent bonding strength, chemical stability and cellular bioactivity, indicating its potential application for orthopaedic implants.

Plasma-sprayed CaTiSiO5 ceramic coating on Ti-6Al-4V with excellent bonding strength, stability and cellular bioactivity

PubMed Central

Wu, Chengtie; Ramaswamy, Yogambha; Liu, Xuanyong; Wang, Guocheng; Zreiqat, Hala

2008-01-01

Novel Ca-Si-Ti-based sphene (CaTiSiO5) ceramics possess excellent chemical stability and cytocompatibility. The aim of this study was to prepare sphene coating on titanium alloy (Ti-6Al-4V) for orthopaedic applications using the plasma spray method. The phase composition, surface and interface microstructure, coating thickness, surface roughness and bonding strength of the plasma-sprayed sphene coating were analysed using X-ray diffraction, scanning electron microscopy, atomic force microscopy and the standard mechanical testing of the American Society for Testing and Materials, respectively. The results indicated that sphene coating was obtained with a uniform and dense microstructure at the interface of the Ti-6Al-4V surface and the thickness and surface roughness of the coating were approximately 150 and 10 μm, respectively. Plasma-sprayed sphene coating on Ti-6Al-4V possessed a significantly improved bonding strength and chemical stability compared with plasma-sprayed hydroxyapatite (HAp) coating. Plasma-sprayed sphene coating supported human osteoblast-like cell (HOB) attachment and significantly enhanced HOB proliferation and differentiation compared with plasma-sprayed HAp coating and uncoated Ti-6Al-4V. Taken together, plasma-sprayed sphene coating on Ti-6Al-4V possessed excellent bonding strength, chemical stability and cellular bioactivity, indicating its potential application for orthopaedic implants. PMID:18664431

First-Principle Investigation on the Bonding Mechanism of the Silicon Particles on the Copper Foil in Cold Spraying

NASA Astrophysics Data System (ADS)

Song, Jun; Liu, Juanfang; Chen, Qinghua

For lithium-ion batteries, the composite silicon-based electrodes can prevent from losing electrical contact and hence retain the capacity over many cycles. To uncover the adhesion mechanism on the interface formed by the copper foil and the thin silicon coatings during the cold gas dynamic spraying (CGDS) at the microscopic level, the first-principle calculations are performed to investigate the interface properties between them. The ideal work of adhesion, fracture toughness and the interface electronic properties are analyzed. It is found that all the atoms on the interface have vertical displacements, and covalent and ionic bonds are formed between the interfacial Cu and Si atoms which increases the bonding strength. However, the ideal work of adhesion on the interface is lower than one of the Cu bulk and Si bulk, so that fracture would be easier to take place on the interface.

Hybrid electro-optics and chipscale integration of electronics and photonics

NASA Astrophysics Data System (ADS)

Dalton, L. R.; Robinson, B. H.; Elder, D. L.; Tillack, A. F.; Johnson, L. E.

2017-08-01

Taken together, theory-guided nano-engineering of organic electro-optic materials and hybrid device architectures have permitted dramatic improvement of the performance of electro-optic devices. For example, the voltage-length product has been improved by nearly a factor of 104 , bandwidths have been extended to nearly 200 GHz, device footprints reduced to less than 200 μm2 , and femtojoule energy efficiency achieved. This presentation discusses the utilization of new coarse-grained theoretical methods and advanced quantum mechanical methods to quantitatively simulate the physical properties of new classes of organic electro-optic materials and to evaluate their performance in nanoscopic device architectures, accounting for the effect on chromophore ordering at interfaces in nanoscopic waveguides.

Lagrangian Modeling of Evaporating Sprays at Diesel Engine Conditions: Effects of Multi-Hole Injector Nozzles With JP-8 Surrogates

DTIC Science & Technology

2014-05-01

solver to treat the spray process. An Adaptive Mesh Refinement (AMR) and fixed embedding technique is employed to capture the gas - liquid interface with...Adaptive Mesh Refinement (AMR) and fixed embedding technique is employed to capture the gas - liquid interface with high fidelity while keeping the cell...in single and multi-hole nozzle configurations. The models were added to the present CONVERGE liquid fuel database and validated extensively

[Investigation on Spray Drying Technology of Auricularia auricular Extract].

PubMed

Zhou, Rong; Chen, Hui; Xie, Yuan; Chen, Peng; Wang, Luo-lin

2015-07-01

To investigate the feasibility of spray drying technology of Auricularia auricular extract and its optimum process. On the basis of single factor test, with the yield of dry extract and the content of polysaccharide as indexes, orthogonal test method was used to optimize the spray drying technology on the inlet air temperature, injection speed and crude drug content. Using ultraviolet spectrophotometry, thin layer chromatography(TLC) and pharmacodynamics as indicators, extracts prepared by traditional alcohol precipitation drying process and spray drying process were compared. Compared with the traditional preparation method, the extract prepared by spray drying had little differences from the polysaccharide content, TLC and the function of reducing TG and TC, and its optimum technology condition were as follows: The inlet air temperature was 180 °C, injection speed was 10 ml/min and crude drugs content was 0. 4 g/mL. Auricularia auricular extract by spray drying technology is stable and feasible with high economic benefit.

Integration of electrochemistry with ultra-performance liquid chromatography/mass spectrometry.

PubMed

Cai, Yi; Zheng, Qiuling; Liu, Yong; Helmy, Roy; Loo, Joseph A; Chen, Hao

2015-01-01

This study presents the development of ultra-performance liquid chromatography (UPLC) mass spectrometry (MS) combined with electrochemistry (EC) for the first time and its application for the structural analysis of proteins/peptides that contain disulfide bonds. In our approach, a protein/peptide mixture sample undergoes a fast UPLC separation and subsequent electrochemical reduction in an electrochemical flow cell followed by online MS and tandem mass spectrometry (MS/MS) analyses. The electrochemical cell is coupled to the mass spectrometer using our recently developed desorption electrospray ionization (DESI) interface. Using this UPLC/EC/DESI-MS method, peptides that contain disulfide bonds can be differentiated from those without disulfide bonds, as the former are electroactive and reducible. MS/MS analysis of the disulfide-reduced peptide ions provides increased information on the sequence and disulfide-linkage pattern. In a reactive DESI- MS detection experiment in which a supercharging reagent was used to dope the DESI spray solvent, increased charging was obtained for the UPLC-separated proteins. Strikingly, upon online electrolytic reduction, supercharged proteins (e.g., α-lactalbumin) showed even higher charging, which will be useful in top- down protein structure MS analysis as increased charges are known to promote protein ion dissociation. Also, the separation speed and sensitivity are enhanced by approximately 1(~)2 orders of magnitude by using UPLC for the liquid chromatography (LC)/EC/MS platform, in comparison to the previously used high- performance liquid chromatography (HPLC). This UPLC/EC/DESI-MS method combines the power of fast UPLC separation, fast electrochemical conversion, and online MS structural analysis for a potentially valuable tool for proteomics research and bioanalysis.

Investigation of DBS electro-oxidation reaction in the aqueous-organic solution of LiClO4.

PubMed

Darlewski, Witold; Popiel, Stanisław; Nalepa, Tomasz; Gromotowicz, Waldemar; Szewczyk, Rafał; Stankiewicz, Romuald

2010-03-15

A process of dibutyl sulphide (DBS) electro-oxidation using electrolysis and cyclic voltamperometry was investigated in water-methanol solution using different electrodes (platinum, boron doped diamond, graphite and glassy carbon). Obtained results indicate that the DBS electro-oxidation process is irreversible in voltamperometric conditions. It was shown that during DBS electrolytic oxidation on Pt, at the low anode potential (1.8 V), DBS was oxidized to sulphoxide and sulphone. Electrolysis at higher potential (up to 3.0 V) resulted in complete DBS oxidation and formation of various products, including: butyric acid, sulphuric acid, butanesulphinic acid, butanesulphonic acid, identified using gas chromatography (GC-AED) and mass spectrometry (GC-MS) methods. (c) 2009 Elsevier B.V. All rights reserved.

Bismuth Titanate Fabricated by Spray-on Deposition and Microwave Sintering For High-Temperature Ultrasonic Transducers.

PubMed

Searfass, Clifford T; Pheil, C; Sinding, K; Tittmann, B R; Baba, A; Agrawal, D K

2016-01-01

Thick films of ferroelectric bismuth titanate (Bi4Ti3O12) have been fabricated by spray-on deposition in conjunction with microwave sintering for use as high-temperature ultrasonic transducers. The elastic modulus, density, permittivity, and conductivity of the films were characterized. Electro-mechanical properties of the films were estimated with a commercial d33 meter which gave 16 pC/N. This value is higher than typically reported for bulk bismuth titanate; however, these films withstand higher field strengths during poling which is correlated with higher d33 values. Films were capable of operating at 650 °C for roughly 5 min before depoling and can operate at 600 °C for at least 7 days.

Mass and charge transport in IPMC actuators with fractal interfaces

NASA Astrophysics Data System (ADS)

Chang, Longfei; Wu, Yucheng; Zhu, Zicai; Li, Heng

2016-04-01

Ionic Polymer-Metal Composite (IPMC) actuators have been attracting a growing interest in extensive applications, which consequently raises the demands on the accuracy of its theoretical modeling. For the last few years, rough landscape of the interface between the electrode and the ionic membrane of IPMC has been well-documented as one of the key elements to ensure a satisfied performance. However, in most of the available work, the interface morphology of IPMC was simplified with structural idealization, which lead to perplexity in the physical interpretation on its interface mechanism. In this paper, the quasi-random rough interface of IPMC was described with fractal dimension and scaling parameters. And the electro-chemical field was modeled by Poisson equation and a properly simplified Nernst-Planck equation set. Then, by simulation with Finite Element Method, a comprehensive analysis on he inner mass and charge transportation in IPMC actuators with different fractal interfaces was provided, which may be further adopted to instruct the performance-oriented interface design for ionic electro-active actuators. The results also verified that rough interface can impact the electrical and mechanical response of IPMC, not only from the respect of the real surface increase, but also from mass distribution difference caused by the complexity of the micro profile.

Fabrication of Nanosized Lanthanum Zirconate Powder and Deposition of Thermal Barrier Coating by Plasma Spray Process

NASA Astrophysics Data System (ADS)

Mishra, S. K.; Jagdeesh, N.; Pathak, L. C.

2016-07-01

The present manuscript discusses our findings on fabrication of nanosized lanthanum zirconate powder for thermal barrier coating application and its coating by plasma spray on nickel-based superalloy substrate. Single-phase La2Zr2O7 coating of thickness of the order of 45 µm on the Ni-Cr-Al bond coat coated Ni-based superalloy substrate was deposited by plasma spray process. The layers at the interface did not show spallation and inter diffusion was very less. The microstructure, interface, porosity, and mechanical properties of different layers are investigated. The lanthanum zirconate hardness and modulus were 10.5 and 277 GPa, respectively. The load depth curve for lanthanum zirconate showed good elastic recovery around 74%.

Simultaneous screening for 238 drugs in blood by liquid chromatography-ion spray tandem mass spectrometry with multiple-reaction monitoring.

PubMed

Gergov, M; Ojanperä, I; Vuori, E

2003-09-25

A liquid chromatography-tandem mass spectrometry (LC-MS-MS) method is presented for the qualitative screening for 238 drugs in blood samples, which is considerably more than in previous methods. After a two-step liquid-liquid extraction and C(18) chromatography, the compounds were introduced into a triple quadrupole mass spectrometer equipped with a turbo ion spray ion source operating in the positive ionization mode. Identification was based on the compound's absolute retention time, protonated molecular ion, and one representative fragment ion obtained by multiple reaction monitoring (MRM) at an individually selected collision energy of 20, 35, or 50 eV. The limit of detection (LOD) for the majority of the compounds (80%) was < or = 0.05 mg/l, ranging from 0.002 mg/l (e.g., antihistamines) to 5 mg/l (acidic compounds), and for malathion it was 10 mg/l. The LOD values were sufficiently low to allow the majority of compounds to be detected at therapeutic concentrations in the blood.

Spray combustion at normal and reduced gravity in counterflow and co-flow configurations

NASA Technical Reports Server (NTRS)

Gomez, Alessandro; Chen, Gung

1995-01-01

Liquid fuel dispersion in practical systems is typically achieved by spraying the fuel into a polydisperse distribution of droplets evaporating and burning in a turbulent gaseous environment In view of the nearly insurmountable difficulties of this two-phase flow, a systematic study of spray evaporation and burning in configurations of gradually increasing levels of complexity, starting from laminar sprays to fully turbulent ones, would be useful. A few years ago we proposed to use an electrostatic spray of charged droplets for this type of combustion experiments under well-defined conditions. In the simplest configuration, a liquid is fed into a small metal tube maintained at several kilovolts relative to a ground electrode few centimeters away. Under the action of the electric field, the liquid meniscus at the outlet of the capillary takes a conical shape, with a thin jet emerging from the cone tip (cone-jet mode). This jet breaks up farther downstream into a spray of charged droplets - the so-called ElectroSpray (ES). Several advantages distinguish the electrospray from alternative atomization techniques: (1) it can produce quasi-monodisperse droplets over a phenomenal size range; (2) the atomization, that is strictly electrostatic, is decoupled from gas flow processes, which provides some flexibility in the selection and control of the experimental conditions; (3) the Coulombic repulsion of homopolarly charged droplets induces spray self-dispersion and prevents droplet coalescence; (4) the ES provides the opportunity of studying regimes of slip between droplets and host gas without compromising the control of the spray properties; and (5) the compactness and potential controllability of this spray generation system makes it appealing for studies in reduced-gravity environments aimed at isolating the spray behavior from natural convection complications. With these premises, in March 1991 we initiated a series of experiments under NASA sponsorship (NAG3-1259 and 1688) in which the ES was used as a research tool to examine spray combustion in counter-flow and co-flow spray diffusion flames, as summarized below. The ultimate objective of this investigation is to examine the formation and burning of sprays of liquid fuels, at both normal and reduced gravity, first in laminar regimes and then in turbulent ones.

Influence of microstructure on hardness of plasma sprayed Al2O3-TiO2-MgO coatings with interface diffusion by heat treatment

NASA Astrophysics Data System (ADS)

Chen, Kunlun; Song, Peng; Li, Chao; Lu, Jiansheng

2017-12-01

The effect of heat treatment on the microstructure and mechanical properties of Al2O3-TiO2 coatings doped with 5 wt% MgO was investigated in this paper. The composite coatings were prepared by atmospheric plasma spraying (APS) and heat treated at 1000 °C for 24 h in Ar. The coatings were analyzed using scanning electron microscopy with electron probe x-ray microanalysis and x-ray diffraction. The hardness was determined using a Vickers hardness test on the as-sprayed coatings and after heat treatment. The results showed that the interface diffusion between the Al-rich and Ti-rich layers resulted in mutual pinning within the coating during the heat treatment. The newly formed MgAl2O4 phase promoted cracking-healing behavior within the coating. We conclude that increase of the hardness of the coatings was mainly caused by the mutual pinning interface and crack healing.

The application of electrolytic photoetching and photopolishing to AISI 304 stainless steel and the electrolytic photoetching of amorphous cobalt alloy

NASA Astrophysics Data System (ADS)

Thomaz, Marita Duarte Canhao da Silva Pereira Fernandes

The results presented cover broad aspects of a quantitative investigation into the elecrolytic etching and polishing of metals and alloys through photographically produced dielectric stencils (Photoresists). A study of the potential field generated between a cathode and relatively smaller anode sites as those defined by a dielectric stencil was carried out. Numerical, analytical and graphical methods yielded answers to the factors determining lateral dissolution (undercut) at the anode/stencil interface. A quasi steady state numerical model simulating the transient behavior of the partially masked electrodes undergoing dissolution was obtained. AISI 304 stainless steel was electrolytically photoetched in 10% w/w HCl electrolyte. The optimised process parameters were utilised for quantifying the effects of galvanostatic etching of the anode as that defined by a relatively narrow adherent resist stencil. Stainless steel was also utilised in investigating electrolytic photopolishing. A polishing electrolyte (orthophosphoric acid-glycerol) was modified by the addition of a surfactant which yielded surface texture values of 70nm (Ra) and high levels of specular reflectance. These results were used in the production of features upon the metal surface through photographically produced precision stencils. The process was applied to the production of edge filters requiring high quality surface textures in precision recesses. Some of the new amorphous material exhibited high resistance to dissolution in commercially used spray etching formulations. One of these materials is a cobalt based alloy produced by chill block spinning. This material was also investigated and electro etched in 10% w/w HCl solution. Although passivity was not overcome, by selecting suitable operating parameters the successful electro photoetching of precision magnetic recording head laminations was achieved. Similarly, a polycrystalline nickel based alloy also exhibiting passivity in commercially used etchants was successfully etched in the above electrolyte.

Silica Coated Paper Substrate for Paper-Spray Analysis of Therapeutic Drugs in Dried Blood Spots

PubMed Central

Zhang, Zhiping; Xu, Wei; Manicke, Nicholas E.; Cooks, R. Graham; Ouyang, Zheng

2011-01-01

Paper spray is a newly developed ambient ionization method that has been applied for direct qualitative and quantitative analysis of biological samples. The properties of the paper substrate and spray solution have a significant impact on the release of chemical compounds from complex sample matrices, the diffusion of the analytes through the substrate, and the formation of ions for mass spectrometry analysis. In this study, a commercially available silica-coated paper was explored in an attempt to improve the analysis of therapeutic drugs in dried blood spots (DBS). The dichloromethane/isopropanol solvent has been identified as an optimal spray solvent for the analysis. The comparison was made with paper spray using chromatography paper as substrate with methanol/water as solvent for the analysis of verapamil, citalopram, amitriptyline, lidocaine and sunitinib in dried blood spots. It has been demonstrated the efficiency of recovery of the analytes was notably improved with the silica coated paper and the limit of quantitation (LOQ) for the drug analysis was 0.1 ng mL−1 using a commercial triple quadrupole mass spectrometer. The use of silica paper substrate also resulted in a sensitivity improvement of 5-50 fold in comparison with chromatography papers, including the Whatmann ET31 paper used for blood card. Analysis using a handheld miniature mass spectrometer Mini 11 gave LOQs of 10~20 ng mL−1 for the tested drugs, which is sufficient to cover the therapeutic ranges of these drugs. PMID:22145627

Development and Characterization of Sodium Hyaluronate Microparticle-Based Sustained Release Formulation of Recombinant Human Growth Hormone Prepared by Spray-Drying.

PubMed

Kim, Sun J; Kim, Chan W

2016-02-01

The purpose of this study was to develop and characterize a sodium hyaluronate microparticle-based sustained release formulation of recombinant human growth hormone (SR-rhGH) prepared by spray-drying. Compared to freeze-drying, spray-dried SR-rhGH showed not only prolonged release profiles but also better particle property and injectability. The results of size-exclusion high-performance liquid chromatography showed that no aggregate was detected, and dimer was just about 2% and also did not increase with increase of inlet temperature up to 150 °C. Meanwhile, the results of reversed-phase high-performance liquid chromatography revealed that related proteins increased slightly from 4.6% at 100 °C to 6.3% at 150 °C. Thermal mapping test proved that product temperature did not become high to cause protein degradation during spray-drying because thermal energy was used for the evaporation of surface moisture of droplets. The structural characterization by peptide mapping, sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and circular dichroism revealed that the primary, secondary, and tertiary structures of rhGH in SR-rhGH were highly comparable to those of reference somatropin materials. The biological characterization by rat weight gain and cell proliferation assays provided that bioactivity of SR-rhGH was equivalent to that of native hGH. These data establish that spray-dried SR-rhGH is highly stable by preserving intact rhGH and hyaluronate microparticle-based formulation by spray-drying can be an alternative delivery system for proteins. Copyright © 2016 American Pharmacists Association®. Published by Elsevier Inc. All rights reserved.

Electro Spray Method for Flexible Display

DTIC Science & Technology

2016-05-12

conditions which expensive and complicated.8-9) Kim et al. reported the fabrication of IZO thin films via combustion processing and obtained mobility values...metal nitrates as metal sources in solutions. Through the high self-generated energies by the combustion of acetylacetone or urea in solution...barrier to increase the mobility of solution-process-derived TFTs. Therefore, we used H2O as the solvent in our precursor solution. The use of H2O

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

Shoup, R.W.; Long, F.; Martin, T.H.

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

Electro-Active Polymer Based Soft Tactile Interface for Wearable Devices.

PubMed

Mun, Seongcheol; Yun, Sungryul; Nam, Saekwang; Park, Seung Koo; Park, Suntak; Park, Bong Je; Lim, Jeong Mook; Kyung, Ki-Uk

2018-01-01

This paper reports soft actuator based tactile stimulation interfaces applicable to wearable devices. The soft actuator is prepared by multi-layered accumulation of thin electro-active polymer (EAP) films. The multi-layered actuator is designed to produce electrically-induced convex protrusive deformation, which can be dynamically programmable for wide range of tactile stimuli. The maximum vertical protrusion is and the output force is up to 255 mN. The soft actuators are embedded into the fingertip part of a glove and front part of a forearm band, respectively. We have conducted two kinds of experiments with 15 subjects. Perceived magnitudes of actuator's protrusion and vibrotactile intensity were measured with frequency of 1 Hz and 191 Hz, respectively. Analysis of the user tests shows participants perceive variation of protrusion height at the finger pad and modulation of vibration intensity through the proposed soft actuator based tactile interface.

The effect of stem surface treatment and material on pistoning of ulnar components in linked cemented elbow prostheses.

PubMed

Hosein, Yara K; King, Graham J W; Dunning, Cynthia E

2013-09-01

The ulnar component of a total elbow replacement can fail by "pistoning." Stem surface treatments have improved stability at the stem-cement interface but with varied success. This study investigated the role of surface treatment and stem substrate material on implant stability under axial loading. Sixty circular stems (diameter, 8 mm) made of cobalt chrome (n = 30) or titanium (n = 30) had different surfaces: smooth, sintered beads, and plasma spray. The surface treatment length was either 10 mm or 20 mm. Stems were potted in bone cement, allowed to cure for 24 hours, and tested in a materials testing machine under a compressive staircase loading protocol. Failure was defined as 2 mm of push-out or completion of the protocol. Two-way analyses of variance compared the effects of surface treatment and substrate material on interface strength and motion. Significant interactions were found between surface treatment and substrate material for both interface strength and motion (P < .05). For titanium, the 20-mm beaded stems had greater interface strength than all other stems (P < .05) and had less motion than the 10-mm plasma-spray and smooth stems (P < .05). For cobalt chrome, the 20-mm beaded stems showed greater interface strength (P < .05) and similar motion (P > .05) to the 20-mm plasma-spray stems (P < .05), which outperformed all other stems (P < .05). Mechanisms of catastrophic failure varied: smooth stems debonded at the stem-cement interface, beaded stems experienced debonding of the beads from the stem, and plasma-spray stems showed loss of frictional force between the surface treatment and cement. Stem surface treatment can enhance ulnar component stability but is dependent on substrate material. Copyright © 2013 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Mosby, Inc. All rights reserved.

Mass Spectrometry for Research and Application in Therapeutic Drug Monitoring or Clinical and Forensic Toxicology.

PubMed

Maurer, Hans H

2018-04-30

This paper reviews current applications of various hyphenated low- and high-resolution mass spectrometry techniques in the field of therapeutic drug monitoring and clinical/forensic toxicology in both research and practice. They cover gas chromatography, liquid chromatography, matrix-assisted laser desorption ionization, or paper spray ionization coupled to quadrupole, ion trap, time-of-flight, or Orbitrap mass analyzers.

Acrylamide: formation, occurrence in food products, detection methods, and legislation.

PubMed

Arvanitoyannis, Ioannis S; Dionisopoulou, Niki

2014-01-01

This review aims at summarizing the most recent updates in the field of acrylamide (AA) formation (mechanism, conditions) and the determination of AA in a number of foods (fried or baked potatoes, chips, coffee, bread, etc). The methods applied for AA detection [Capillary Electrophoresis-Mass Spectrometry (CE-MS), Liquid Chromatography-Mass Spectrometry (LC-MS), Non-Aqueous Capillary Electrophoresis (NACE), High Performance Liquid Chromatography-Mass Spectrometry (HPLC-MS), Pressurized Fluid Extraction (PFE), Matrix Solid-Phase Dispersion (MSPD), Gas Chromatography-Mass Spectrometry (GC-MS), Solid-Phase MicroExtraction-Gas Chromatography (SPME-GC), Enzyme Linked Immunosorbent Assay (ELISA), and MicroEmulsion ElectroKinetic Chromatography (MEEKC) are presented and commented. Several informative figures and tables are included to show the effect of conditions (temperature, time) on the AA formation. A section is also included related to AA legislation in EU and US.

Improved simultaneous quantitation of candesartan and hydrochlorthiazide in human plasma by UPLC-MS/MS and its application in bioequivalence studies.

PubMed

Singh, Bhupinder; Lokhandae, Rama S; Dwivedi, Ashish; Sharma, Sandeep; Dubey, Naveen

2014-04-01

A validated ultra-performance liquid chromatography mass spectrometric method (UPLC-MS/MS) was used for the simultaneous quantitation of candesartan (CN) and hydrochlorothiazide (HCT) in human plasma. The analysis was performed on UPLC-MS/MS system using turbo ion spray interface. Negative ions were measured in multiple reaction monitoring (MRM) mode. The analytes were extracted using a liquid-liquid extraction (LLE) method by using 0.1 mL of plasma volume. The lower limit of quantitation for CN and HCT was 1.00 ng/mL whereas the upper limit of quantitation was 499.15 ng/mL and 601.61 ng/mL for CN and HCT respectively. CN d 4 and HCT- 13 Cd 2 were used as the internal standards for CN and HCT respectively. The chromatography was achieved within 2.0 min run time using a C18 Phenomenex, Gemini NX (100 mm×4.6 mm, 5 µm) column with organic mixture:buffer solution (80:20, v/v) at a flow rate of 0.800 mL/min. The method has been successfully applied to establish the bioequivalence of candesartan cilexetil (CNC) and HCT immediate release tablets with reference product in human subjects.

Integration of Flex Nozzle System and Electro Hydraulic Actuators to Solid Rocket Motors

NASA Astrophysics Data System (ADS)

Nayani, Kishore Nath; Bajaj, Dinesh Kumar

2017-10-01

A rocket motor assembly comprised of solid rocket motor and flex nozzle system. Integration of flex nozzle system and hydraulic actuators to the solid rocket motors are done after transportation to the required place where integration occurred. The flex nozzle system is integrated to the rocket motor in horizontal condition and the electro hydraulic actuators are assembled to the flex nozzle systems. The electro hydraulic actuators are connected to the hydraulic power pack to operate the actuators. The nozzle-motor critical interface are insulation diametrical compression, inhibition resin-28, insulation facial compression, shaft seal `O' ring compression and face seal `O' ring compression.

Electro-optic architecture for servicing sensors and actuators in advanced aircraft propulsion systems

NASA Technical Reports Server (NTRS)

Poppel, G. L.; Glasheen, W. M.

1989-01-01

A detailed design of a fiber optic propulsion control system, integrating favored sensors and electro-optics architecture is presented. Layouts, schematics, and sensor lists describe an advanced fighter engine system model. Components and attributes of candidate fiber optic sensors are identified, and evaluation criteria are used in a trade study resulting in favored sensors for each measurand. System architectural ground rules were applied to accomplish an electro-optics architecture for the favored sensors. A key result was a considerable reduction in signal conductors. Drawings, schematics, specifications, and printed circuit board layouts describe the detailed system design, including application of a planar optical waveguide interface.

Thermophysical properties of plasma sprayed coatings

NASA Technical Reports Server (NTRS)

Wilkes, K. E.; Lagedrost, J. F.

1973-01-01

Thermophysical properties of plasma sprayed materials were determined for the following plasma sprayed materials: CaO - stabilized ZrO2, Y2O3 - stabilized ZerO2, Al2O3, HfO2 Mo, nichrome, NiAl, Mo-ZrO2, and MoAl2O3 mixtures. In all cases the thermal conductivity of the as-sprayed materials was found to be considerably lower than that of the bulk material. The flash-laser thermal diffusivity technique was used both for diffusivity determination of single-layer materials and to determine the thermal contact resistance at the interface of two-layer specimens.

Plasma spray processing of TiC-based coatings for sliding wear resistance

NASA Astrophysics Data System (ADS)

Mohanty, Mahesh

Titanium carbide-reinforced metallic coatings, produced by plasma spraying, can be used for sliding wear resistant applications. The sliding wear properties of such coatings are governed to a large extent by the strength, structure and stability of the bond interface between the carbide and the metallic phases. In the present investigation, the microstructure and sliding wear properties of plasma sprayed metal-bonded TiC coatings containing up to 90 v/o carbide have been studied. It was shown that alloying of the metallic phase improved carbide retention in TiC cermets due to better interface bonding, and increased wear resistance and lowered sliding coefficient of friction. TiC-based coatings were produced from both physically blended and synthesized feed powders. It was observed that the precursor TiC-based powder morphology and structure greatly affected the plasma sprayed coating microstructures and the resultant physical and mechanical characteristics. Physical blending of powders induced segregation during spraying, leading to somewhat lower deposit efficiencies and coating uniformity, while synthesized and alloyed titanium carbide/metal composite powders reduced problems of segregation and reactions associated with plasma spraying of physically blended powders where the TiC was in direct contact with the plasma jet. To understand oxidation effects of the environment, Ti and TiC-based coatings were produced under low pressure (VPS), air plasma (APS) and shrouded plasma sprayed conditions. APS Ti and TiC-based powders with reactive matrices suffered severe oxidation decomposition during flight, leading to poor deposition efficiencies and oxidized microstructures. High particle temperatures and cold air plasma spraying. Coating oxidation due to reactions of the particles with the surrounding air during spraying reduced coating hardness and wear resistance. TiC-with Ti or Ti-alloy matrix coatings with the highest hardness, density and wear resistance was achieved by spraying under vacuum plasma spray conditions. VPS coating microstructures of synthesized 40, 60 and 80 v/o TiC in Ti10Ni10Cr5Al and 80 v/o TiC in Fe30Cr alloy matrices exhibited fine and uniform distributions of spheroidal carbides. High volume fraction carbides were also obtained with no segregation effects. It was also shown that coatings produced from mechanically blended powders of 50, 70 and 90 vol. % TiC and commercially pure (C.P.) Ti, using low pressure plasma spray process (VPS), had densities >98% and were well bonded to steel, aluminum alloy or titanium alloy substrates. Reductions in jet oxygen contents by the use of an inert gas shroud enabled Ti and TiC-based coatings to be produced which were cleaner and denser than air plasma sprayed and comparable to vacuum plasma sprayed coatings. Direct oxygen concentration measurements in shrouded plasma jets made using an enthalpy probe and a gas analyzer also showed significant reductions in the entrainment of atmospheric oxygen. VPS and shrouded plasma spraying minimized carbide-matrix interface oxidation and improved coating wear resistance. The sliding wear resistance of synthesized coatings was very high and comparable with standard HVOF sprayed WC/Co and Crsb3Csb2/NiCr coatings. Shrouded plasma spray deposits of Crsb3Csb2/NiCr also performed much better than similar air plasma sprayed coatings, as result of reduced oxidation.

Electro-Deposited Primer Development and Low-Polluting Primer Evaluation

DTIC Science & Technology

1989-08-01

in the use of spray-applied primers are nonuniform corrosion protection, poor control of primer thickness, and variable strength of the adhesive bond...AL=)r- U’) LA C) .LAV) . L" () - C:’. L L :0 3c’. ) %D r- LAIr - LA I r-.%D ’D( o oD𔃺t- LA Ln DLI m to r- 0 0l- I cn M - in C.0 CD I (n m~ : c) = I V

Effect of the Cold-Sprayed Aluminum Coating-Substrate Interface Morphology on Bond Strength for Aircraft Repair Application

NASA Astrophysics Data System (ADS)

Blochet, Quentin; Delloro, Francesco; N'Guyen, Franck; Jeulin, Dominique; Borit, François; Jeandin, Michel

2017-04-01

This article is dealing with the effects of surface preparation of the substrate on aluminum cold-sprayed coating bond strength. Different sets of AA2024-T3 specimens have been coated with pure Al 1050 feedstock powder, using a conventional cold spray coating technique. The sets were grit-blasted (GB) before coating. The study focuses on substrate surface topography evolution before coating and coating-substrate interface morphology after coating. To study coating adhesion by LASAT® technique for each set, specimens with and without preceding GB treatment were tested in load-controlled conditions. Then, several techniques were used to evaluate the effects of substrate surface treatment on the final coating mechanical properties. Irregularities induced by the GB treatment modify significantly the interface morphology. Results showed that particle anchoring was improved dramatically by the presence of craters. The substrate surface was characterized by numerous anchors. Numerical simulation results exhibited the increasing deformation of particle onto the grit-blasted surface. In addition, results showed a strong relationship between the coating-substrate bond strength on the deposited material and surface preparation.

Inter-subunit interactions across the upper voltage sensing-pore domain interface contribute to the concerted pore opening transition of Kv channels.

PubMed

Shem-Ad, Tzilhav; Irit, Orr; Yifrach, Ofer

2013-01-01

The tight electro-mechanical coupling between the voltage-sensing and pore domains of Kv channels lies at the heart of their fundamental roles in electrical signaling. Structural data have identified two voltage sensor pore inter-domain interaction surfaces, thus providing a framework to explain the molecular basis for the tight coupling of these domains. While the contribution of the intra-subunit lower domain interface to the electro-mechanical coupling that underlies channel opening is relatively well understood, the contribution of the inter-subunit upper interface to channel gating is not yet clear. Relying on energy perturbation and thermodynamic coupling analyses of tandem-dimeric Shaker Kv channels, we show that mutation of upper interface residues from both sides of the voltage sensor-pore domain interface stabilizes the closed channel state. These mutations, however, do not affect slow inactivation gating. We, moreover, find that upper interface residues form a network of state-dependent interactions that stabilize the open channel state. Finally, we note that the observed residue interaction network does not change during slow inactivation gating. The upper voltage sensing-pore interaction surface thus only undergoes conformational rearrangements during channel activation gating. We suggest that inter-subunit interactions across the upper domain interface mediate allosteric communication between channel subunits that contributes to the concerted nature of the late pore opening transition of Kv channels.

Asymmetrical bonding in cold spraying of dissimilar materials

NASA Astrophysics Data System (ADS)

Nikbakht, R.; Seyedein, S. H.; Kheirandish, S.; Assadi, H.; Jodoin, B.

2018-06-01

Characteristics of particle bonding, especially for dissimilar materials, remains a key question in cold spray deposition. There are limited reports in direct correlation to particle/substrate bonding and peripheral shear zones. Cold spraying experiments and numerical simulations are conducted to characterise and analyse the correlation between bonding and peripheral shear zones for asymmetric particle/substrate pairs of intermetallic-forming elements of nickel and titanium. The correlation between metallic bonding and highly strained areas is explored in view of the growth of the intermetallic phase at the particle/substrate interface during subsequent heat treatments. Characterisation of the as-sprayed samples reveal that for the Ni(particle)/Ti(substrate) pair, plastic deformation of the particle is dominating over substrate deformation. However, for the Ti(particle)/Ni(substrate) pair, it is observed that the substrate and particle deform to similar extents. Characterisation of the samples after a brief heat treatment at 700 °C indicate that intermetallic formation, and hence metallurgical bonding of the pairs is more likely to occur at the particle peripheries where the interface areas are highly strained, and rarely achieved at the particle base. Results also reveal that bonding extends from peripheries toward the central part of the interfaces with increasing the impact velocity. The kinetics of interfacial intermetallic formation at peripheral areas and its correlation to particle bonding is discussed in view of deformation-enhanced interdiffusion.

Analytical solution of two-fluid electro-osmotic flows of viscoelastic fluids.

PubMed

Afonso, A M; Alves, M A; Pinho, F T

2013-04-01

This paper presents an analytical model that describes a two-fluid electro-osmotic flow of stratified fluids with Newtonian or viscoelastic rheological behavior. This is the principle of operation of an electro-osmotic two-fluid pump as proposed by Brask et al. [Tech. Proc. Nanotech., 1, 190-193, 2003], in which an electrically non-conducting fluid is transported by the interfacial dragging viscous force of a conducting fluid that is driven by electro-osmosis. The electric potential in the conducting fluid and the analytical steady flow solution of the two-fluid electro-osmotic stratified flow in a planar microchannel are presented by assuming a planar interface between the two immiscible fluids with Newtonian or viscoelastic rheological behavior. The effects of fluid rheology, shear viscosity ratio, holdup and interfacial zeta potential are analyzed to show the viability of this technique, where an enhancement of the flow rate is observed as the shear-thinning effects are increased. Copyright © 2012 Elsevier Inc. All rights reserved.

Degradation of anti-inflammatory drug ketoprofen by electro-oxidation: comparison of electro-Fenton and anodic oxidation processes.

PubMed

Feng, Ling; Oturan, Nihal; van Hullebusch, Eric D; Esposito, Giovanni; Oturan, Mehmet A

2014-01-01

The electrochemical degradation of the nonsteroidal anti-inflammatory drug ketoprofen in tap water has been studied using electro-Fenton (EF) and anodic oxidation (AO) processes with platinium (Pt) and boron-doped diamond (BDD) anodes and carbon felt cathode. Fast degradation of the parent drug molecule and its degradation intermediates leading to complete mineralization was achieved by BDD/carbon felt, Pt/carbon felt, and AO with BDD anode. The obtained results showed that oxidative degradation rate of ketoprofen and mineralization of its aqueous solution increased by increasing applied current. Degradation kinetics fitted well to a pseudo-first-order reaction. Absolute rate constant of the oxidation of ketoprofen by electrochemically generated hydroxyl radicals was determined to be (2.8 ± 0.1) × 10(9) M(-1) s(-1) by using competition kinetic method. Several reaction intermediates such as 3-hydroxybenzoic acid, pyrogallol, catechol, benzophenone, benzoic acid, and hydroquinone were identified by high-performance liquid chromatography (HPLC) analyses. The formation, identification, and evolution of short-chain aliphatic carboxylic acids like formic, acetic, oxalic, glycolic, and glyoxylic acids were monitored with ion exclusion chromatography. Based on the identified aromatic/cyclic intermediates and carboxylic acids as end products before mineralization, a plausible mineralization pathway was proposed. The evolution of the toxicity during treatments was also monitored using Microtox method, showing a faster detoxification with higher applied current values.

Spray pyrolytic deposition of α-MoO3 film and its use in dye-sensitized solar cell

NASA Astrophysics Data System (ADS)

Tamboli, Parvin S.; Jagtap, Chaitali V.; Kadam, Vishal S.; Ingle, Ravi V.; Vhatkar, Rajiv S.; Mahajan, Smita S.; Pathan, Habib M.

2018-04-01

Thermal decomposition of ammonium para molybdate tetrahydrate precursor has been studied to determine degradation temperatures in air atmosphere. Current work explores the synthesis of α-MoO3 films by an economical spray pyrolysis technique using ammonium para molybdate tetrahydrate precursor in the presence of compressed air. A variety of characterization techniques such as X-ray diffraction, scanning electron microscopy, transmission electron microscopy, UV-visible spectroscopy, Fourier transform infrared, and Raman spectroscopy were carried out, and the studies have confirmed that orthorhombic phase formation of MoO3 takes place with spongy mesh-type structure. The study of electro-catalytic activity of α-MoO3 in titania-based dye-sensitized solar cell is also carried out by cyclic voltammetry, electrochemical impedance spectroscopy, and Tafel curves to evaluate its performance as a counter electrode.

Influence of Bondcoat Spray Process on Lifetime of Suspension Plasma-Sprayed Thermal Barrier Coatings

NASA Astrophysics Data System (ADS)

Gupta, M.; Markocsan, N.; Li, X.-H.; Östergren, L.

2017-12-01

Development of thermal barrier coatings (TBCs) manufactured by suspension plasma spraying (SPS) is of high commercial interest as SPS has been shown capable of producing highly porous columnar microstructures similar to the conventionally used electron beam-physical vapor deposition. However, lifetime of SPS coatings needs to be improved further to be used in commercial applications. The bondcoat microstructure as well as topcoat-bondcoat interface topography affects the TBC lifetime significantly. The objective of this work was to investigate the influence of different bondcoat deposition processes for SPS topcoats. In this work, a NiCoCrAlY bondcoat deposited by high velocity air fuel (HVAF) was compared to commercial vacuum plasma-sprayed NiCoCrAlY and PtAl diffusion bondcoats. All bondcoat variations were prepared with and without grit blasting the bondcoat surface. SPS was used to deposit the topcoats on all samples using the same spray parameters. Lifetime of these samples was examined by thermal cyclic fatigue testing. Isothermal heat treatment was performed to study bondcoat oxidation over time. The effect of bondcoat deposition process and interface topography on lifetime in each case has been discussed. The results show that HVAF could be a suitable process for bondcoat deposition in SPS TBCs.

Influence of Bondcoat Spray Process on Lifetime of Suspension Plasma-Sprayed Thermal Barrier Coatings

NASA Astrophysics Data System (ADS)

Gupta, M.; Markocsan, N.; Li, X.-H.; Östergren, L.

2018-01-01

Development of thermal barrier coatings (TBCs) manufactured by suspension plasma spraying (SPS) is of high commercial interest as SPS has been shown capable of producing highly porous columnar microstructures similar to the conventionally used electron beam-physical vapor deposition. However, lifetime of SPS coatings needs to be improved further to be used in commercial applications. The bondcoat microstructure as well as topcoat-bondcoat interface topography affects the TBC lifetime significantly. The objective of this work was to investigate the influence of different bondcoat deposition processes for SPS topcoats. In this work, a NiCoCrAlY bondcoat deposited by high velocity air fuel (HVAF) was compared to commercial vacuum plasma-sprayed NiCoCrAlY and PtAl diffusion bondcoats. All bondcoat variations were prepared with and without grit blasting the bondcoat surface. SPS was used to deposit the topcoats on all samples using the same spray parameters. Lifetime of these samples was examined by thermal cyclic fatigue testing. Isothermal heat treatment was performed to study bondcoat oxidation over time. The effect of bondcoat deposition process and interface topography on lifetime in each case has been discussed. The results show that HVAF could be a suitable process for bondcoat deposition in SPS TBCs.

Concurrent EEG And NIRS Tomographic Imaging Based on Wearable Electro-Optodes

DTIC Science & Technology

2014-04-13

Interfaces   ( BCIs ),   and   other   systems   in   the   same   computational   framework.   Figure   11   below   shows...Improving  Brain-­‐Computer   Interfaces  Using   Independent  Component   Analysis,  In:  Towards  Future   BCIs ,  2012

Simultaneous determination of acetaminophen and dihydrocodeine in human plasma by UPLC-MS/MS: Its pharmacokinetic application.

PubMed

Qiu, Xiangjun; Lou, Dan; Su, Ding; Liu, Zebin; Gao, Pengtao; Zhang, Nan-sheng

2015-06-15

An ultra performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) method was developed and validated to determine acetaminophen (AAP) and dihydrocodeine (DHC) in human plasma simultaneously. Plasma samples were prepared using protein precipitation with acetonitrile, the two analytes and the internal standard midazolam were separated on an Acquity UPLC BEH C18 column and mass spectrometric analysis was performed using a QTrap5500 mass spectrometer coupled with an electro-spray ionization (ESI) source in the positive ion mode. The MRM transitions of m/z 151.2→110.0 and m/z 302.3→199.2 were used to quantify for AAP and DHC, respectively. The linearity of this method was found to be within the concentration range of 50-10000ng/mL for AAP, and 1-100ng/mL for DHC in human plasma, respectively. The lower limit of quantification (LLOQ) was 50ng/mL and 1ng/mL for AAP and DHC in human plasma, respectively. The relative standard deviations (RSD) of intra and inter precision were less than 10% for both AAP and DHC. The analysis time of per sample was 1.0min. The developed and validated method was successfully applied to a pharmacokinetic study of AAP (500mg) with DHC (20mg) capsule in Chinese healthy volunteers (N=20). Copyright © 2015 Elsevier B.V. All rights reserved.

Efficient counter-current chromatographic isolation and structural identification of two new cinnamic acids from Echinacea purpurea.

PubMed

Lu, Ying; Li, JiaYin; Li, MiLu; Hu, Xia; Tan, Jun; Liu, Zhong Hua

2012-10-01

Two new cinnamic acids, 2-O-caffeoyl-3-O-isoferuloyltartaric (3), and 2, 3-di-O-isoferuloyltartaric acid (5), along with three known caffeic acids, cichoric acid (1), 2-O-caffeoyl-3-O-feruloyltartaric acid (2) and 2-O-caffeoyl-3-O-p-coumaroyltartaric acid (4), have been successfully isolated and purified from Echinacea purpurea. In this study, we investigated an efficient method for the preparative isolation and purification of cinnamic acids from E. purpurea by high-speed counter-current chromatography (HSCCC). The separation was performed using a two-phase solvent composed of n-hexane-ethyl-acetate-methanol-0.5% aqueous acetic acid (1:3:1:4, v/v). The upper phase was used as the stationary phase and the lower phase as the mobile phase, with a flow rate of 1.6 mL/min. From 250 mg of crude extracts, 65.1 mg of 1, 8.3 mg of 2, 4.0 mg of 3, 4.5 mg of 4, and 4.3 mg of 5 were isolated in one-step, with purities of 98.5%, 97.7%, 94.6%, 94.3%, and 98.6%, respectively, as evaluated by HPLC-DAD. The chemical structures were identified by electro spray ionization mass spectrometry (ESI-MS) and one- and two-dimensional NMR spectra. HSCCC was very efficient for the separation and purification of the cinnamic acids from

Electrospray Encapsulation of Toll-Like Receptor Agonist Resiquimod in Polymer Microparticles for the Treatment of Visceral Leishmaniasis

DTIC Science & Technology

2013-01-15

production using the methods described below. The remaining cells were analyzed for viability. To the cells still adhered to the culture plate, 180 μL of...2009, 43 (9), 902−910. (23) Jaworek, A. Micro - and nanoparticle production by electro- spraying. Powder Technol. 2007, 176 (1), 18−35. (24) Almeria, B...Jhunjhunwala, S.; Raimondi, G.; Thomson, A. W.; Little, S. R. Delivery of rapamycin to dendritic cells using degradable micro - particles. J

Method for making electro-fluidic connections in microfluidic devices

DOEpatents

Frye-Mason, Gregory C.; Martinez, David; Manginell, Ronald P.; Heller, Edwin J.; Chanchani, Rajen

2004-08-10

A method for forming electro-fluidic interconnections in microfluidic devices comprises forming an electrical connection between matching bond pads on a die containing an active electrical element and a microfluidic substrate and forming a fluidic seal ring that circumscribes the active electrical element and a fluidic feedthrough. Preferably, the electrical connection and the seal ring are formed in a single bonding step. The simple method is particularly useful for chemical microanalytical systems wherein a plurality of microanalytical components, such as a chemical preconcentrator, a gas chromatography column, and a surface acoustic wave detector, are fluidically interconnected on a hybrid microfluidic substrate having electrical connection to external support electronics.

Integration of Electrochemistry with Ultra Performance Liquid Chromatography/Mass Spectrometry (UPLC/MS)

PubMed Central

Cai, Yi; Zheng, Qiuling; Liu, Yong; Helmy, Roy; Loo, Joseph A.; Chen, Hao

2015-01-01

This study presents the development of ultra-performance liquid chromatography/mass spectrometry (UPLC/MS) combined with electrochemistry (EC) for the first time and its application for the structural analysis of disulfide bond-containing proteins/peptides. In our approach, a protein/peptide mixture sample undergoes fast UPLC separation and subsequent electrochemical reduction in an electrochemical flow cell followed by online MS and MS/MS analyses. The electrochemical cell is coupled to MS using our recently developed desorption electrospray ionization (DESI) interface. Using this UPLC/EC/DESI-MS method, disulfide bond-containing peptides can be differentiated from those without disulfide bonds as the former are electroactive and reducible. Tandem MS analysis of the disulfide-reduced peptide ions provides increased sequence and disulfide linkage pattern information. In a reactive DESI-MS detection experiment in which a supercharging reagent was used to dope the DESI spray solvent, increased charging was obtained for the UPLC-separated proteins. Strikingly, upon online electrolytic reduction, supercharged proteins (e.g., α-lactalbumin) showed even higher charging, which would be useful in top-down protein structure analysis as increased charges are known to promote protein ion dissociation. Also, the separation speed and sensitivity are enhanced by approximately 1~2 orders of magnitude by using UPLC for the LC/EC/MS platform, in comparison to the previously used high performance liquid chromatography (HPLC). This UPLC/EC/DESI-MS method combines the power of fast UPLC separation, fast electrochemical conversion and online MS structural analysis for a potentially valuable tool for proteomics research and bioanalysis. PMID:26307715

Quantitative Profiling of Endogenous Fat-Soluble Vitamins and Carotenoids in Human Plasma Using an Improved UHPSFC-ESI-MS Interface.

PubMed

Petruzziello, Filomena; Grand-Guillaume Perrenoud, Alexandre; Thorimbert, Anita; Fogwill, Michael; Rezzi, Serge

2017-07-18

Analytical solutions enabling the quantification of circulating levels of liposoluble micronutrients such as vitamins and carotenoids are currently limited to either single or a reduced panel of analytes. The requirement to use multiple approaches hampers the investigation of the biological variability on a large number of samples in a time and cost efficient manner. With the goal to develop high-throughput and robust quantitative methods for the profiling of micronutrients in human plasma, we introduce a novel, validated workflow for the determination of 14 fat-soluble vitamins and carotenoids in a single run. Automated supported liquid extraction was optimized and implemented to simultaneously parallelize 48 samples in 1 h, and the analytes were measured using ultrahigh-performance supercritical fluid chromatography coupled to tandem mass spectrometry in less than 8 min. An improved mass spectrometry interface hardware was built up to minimize the post-decompression volume and to allow better control of the chromatographic effluent density on its route toward and into the ion source. In addition, a specific make-up solvent condition was developed to ensure both analytes and matrix constituents solubility after mobile phase decompression. The optimized interface resulted in improved spray plume stability and conserved matrix compounds solubility leading to enhanced hyphenation robustness while ensuring both suitable analytical repeatability and improved the detection sensitivity. The overall developed methodology gives recoveries within 85-115%, as well as within and between-day coefficient of variation of 2 and 14%, respectively.

Investigation of the changes in aerosolization behavior between the jet-milled and spray-dried colistin powders through surface energy characterization

PubMed Central

Jong, Teresa; Li, Jian; Mortonx, David A.V.; Zhou, Qi (Tony); Larson, Ian

2016-01-01

This study aimed to investigate the surface energy factors behind improved aerosolization performance of spray-dried colistin powder formulations compared to those produced by jet-milling. Inhalable colistin powder formulations were produced by jet-milling or spray-drying (with or without L-leucine). Scanning electron micrographs showed the jet-milled particles had irregularly angular shapes, while the spray-dried particles were more spherical. Significantly higher fine particle fractions (FPFs) were measured for the spray-dried (43.8-49.6%) vs. the jet-milled formulation (28.4 %) from a Rotahaler at 60L/min; albeit the size distribution of the jet-milled powder was smaller. Surprisingly, addition of L-leucine in the spray drying feed-solution gave no significant improvement in FPF. As measured by inverse gas chromatography, spray-dried formulations had significantly (p<0.001) lower dispersive, specific and total surface energy values and more uniform surface energy distributions than the jet-milled powder. Interestingly, no significant difference was measured in the specific and total surface energy values between the spray-dried formulation with or without L-leucine. Based upon our previous findings in the self-assembling behavior of colistin in aqueous solution and the surface energy data obtained here, we propose the self-assembly of colistin molecules during spray-drying, contributed significantly to the reduction of surface free energy and the superior aerosolization performance. PMID:26886330

Sequential cryogen spraying for heat flux control at the skin surface

NASA Astrophysics Data System (ADS)

Majaron, Boris; Aguilar, Guillermo; Basinger, Brooke; Randeberg, Lise L.; Svaasand, Lars O.; Lavernia, Enrique J.; Nelson, J. Stuart

2001-05-01

Heat transfer rate at the skin-air interface is of critical importance for the benefits of cryogen spray cooling in combination with laser therapy of shallow subsurface skin lesions, such as port-wine stain birthmarks. With some cryogen spray devices, a layer of liquid cryogen builds up on the skin surface during the spurt, which may impair heat transfer across the skin surface due to relatively low thermal conductivity and potentially higher temperature of the liquid cryogen layer as compared to the spray droplets. While the mass flux of cryogen delivery can be adjusted by varying the atomizing nozzle geometry, this may strongly affect other spray properties, such as lateral spread (cone), droplet size, velocity, and temperature distribution. We present here first experiments with sequential cryogen spraying, which may enable accurate mass flux control through variation of spray duty cycle, while minimally affecting other spray characteristics. The observed increase of cooling rate and efficiency at moderate duty cycle levels supports the above described hypothesis of isolating liquid layer, and demonstrates a novel approach to optimization of cryogen spray devices for individual laser dermatological applications.

Electro-osmotic flow of couple stress fluids in a micro-channel propagated by peristalsis

NASA Astrophysics Data System (ADS)

Tripathi, Dharmendra; Yadav, Ashu; Anwar Bég, O.

2017-04-01

A mathematical model is developed for electro-osmotic peristaltic pumping of a non-Newtonian liquid in a deformable micro-channel. Stokes' couple stress fluid model is employed to represent realistic working liquids. The Poisson-Boltzmann equation for electric potential distribution is implemented owing to the presence of an electrical double layer (EDL) in the micro-channel. Using long wavelength, lubrication theory and Debye-Huckel approximations, the linearized transformed dimensionless boundary value problem is solved analytically. The influence of electro-osmotic parameter (inversely proportional to Debye length), maximum electro-osmotic velocity (a function of external applied electrical field) and couple stress parameter on axial velocity, volumetric flow rate, pressure gradient, local wall shear stress and stream function distributions is evaluated in detail with the aid of graphs. The Newtonian fluid case is retrieved as a special case with vanishing couple stress effects. With increasing the couple stress parameter there is a significant increase in the axial pressure gradient whereas the core axial velocity is reduced. An increase in the electro-osmotic parameter both induces flow acceleration in the core region (around the channel centreline) and it also enhances the axial pressure gradient substantially. The study is relevant in the simulation of novel smart bio-inspired space pumps, chromatography and medical micro-scale devices.

Application of electro acoustics for dewatering pharmaceutical sludge

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

Golla, P.S.; Johnson, H.W.

1992-02-01

Application of electro acoustic principles for dewatering has been developed by Battelle Institute. The Department of Energy, Battelle Institute, and Ashbrook-Simon-Hartley, have jointly developed an Electro Acoustic Dewatering press (EAD press). The EAD press applies a combination of mechanical pressure, electrical current and ultrasonics. This press is utilized after conventional dewatering devices and can remove up to 50% water from filtered sludge cake at a fraction of the cost incurred in existing thermal drying devices. The dominant mechanism of sludge dewatering by EAD press is electro-osmosis due to the application of a direct current field. Electro-osmosis is caused by anmore » electrical double layer of oppositely charged ions formed at the solid liquid interface, which is characterized by zeta potential. The ultrasonic fields help electro-osmosis by consolidation of the filter cake and by release of inaccessible liquid. The EAD press has been tested successfully on a variety of materials including apple pomace, corn gluten, sewage sludge, and coal fines. A three week long full scale trial was conducted successfully at a pharmaceutical industry to determine the application of this technology for dewatering waste activated sludge.« less

Electro-oxidation of methanol on gold in alkaline media: Adsorption characteristics of reaction intermediates studied using time resolved electro-chemical impedance and surface plasmon resonance techniques

NASA Astrophysics Data System (ADS)

Assiongbon, K. A.; Roy, D.

2005-12-01

Electro-catalytic oxidation of methanol is the anode reaction in direct methanol fuel cells. We have studied the adsorption characteristics of the intermediate reactants of this multistep reaction on a gold film electrode in alkaline solutions by combining surface plasmon resonance (SPR) measurements with Fourier transform electro-chemical impedance spectroscopy (FT-EIS). Methanol oxidation in this system shows no significant effects of "site poisoning" by chemisorbed CO. Our results suggest that OH - chemisorbed onto Au acts as a stabilizing agent for the surface species of electro-active methanol. Double layer charging/discharging and adsorption/desorption of OH - show more pronounced effects than adsorption/oxidation of methanol in controlling the surface charge density of the Au substrate. These effects are manifested in both the EIS and the SPR data, and serve as key indicators of the surface reaction kinetics. The data presented here describe the important role of adsorbed OH - in electro-catalysis of methanol on Au, and demonstrate how SPR and FT-EIS can be combined for quantitative probing of catalytically active metal-solution interfaces.

Electrowetting on polymer dispersed liquid crystal

NASA Astrophysics Data System (ADS)

Fan, Shih-Kang; Chiu, Cheng-Pu; Lin, Jing-Wei

2009-04-01

Polymer dispersed liquid crystal (PDLC) is used as a dielectric layer in electrowetting. By applying voltage between a liquid droplet and the electrode underlying PDLC, electrowetting occurs at the liquid/PDLC interface accompanied with electro-optic responses of the reoriented LC droplets embedded in PDLC. Two basic experiments investigating the electrowetting by sessile water droplets and the electro-optic effects through squeezed water droplets were design and performed. The basic functions of a liquid lens and droplet manipulations, including transporting, splitting, and merging, were demonstrated.

Enhanced Dielectric Nonlinearity in Epitaxial Pb(0.92)La(0.08)Zr(0.52)Ti(0.48)O(3)

DTIC Science & Technology

2014-04-23

storage capacitors, electro-mechanical, or photo- mechanical transducers, etc.1–3 Among them, Lead zirconate titanate system ( PZT ), which exhibits...and at the interfaces between PZT and electro- des. Recently, lanthanum doped PZT with different Zr/Ti ra- tio, such as 65/35, 53/47, or 20/80, has...been investigated, since it can effectively reduce oxygen vacancy, decrease leakage current, and lower the fatigue and domain pinning.8–10 In general

Preparation and Bond Properties of Thermal Barrier Coatings on Mg Alloy with Sprayed Al or Diffused Mg-Al Intermetallic Interlayer

NASA Astrophysics Data System (ADS)

Fan, Xizhi; Wang, Ying; Zou, Binglin; Gu, Lijian; Huang, Wenzhi; Cao, Xueqiang

2014-02-01

Sprayed Al or diffused Mg-Al layer was designed as interlayer between the thermal barrier coatings (TBCs) and Mg alloy substrate. The effects of the interlayer on the bond properties of the coats were investigated. Al layers were prepared by arc spraying and atmospheric plasma spraying (APS), respectively. Mg-Al diffused layer was obtained after the heat treatment of the sprayed sample (Mg alloy with APS Al coat) at 400 °C. The results show that sprayed Al interlayer does not improve the bond stability of TBCs. The failure of the TBCs on Mg alloy with Al interlayer occurs mainly due to the low strength of Al layer. Mg-Al diffused layer improves corrosion resistance of substrate and the bond interface. The TBCs on Mg alloy with Mg-Al diffused interlayer shows better bond stability than the sample of which the TBCs is directly sprayed on Mg alloy substrate by APS.

In vitro fatigue behaviour of vacuum plasma and detonation gun sprayed hydroxyapatite coatings.

PubMed

Gledhill, H C; Turner, I G; Doyle, C

2001-06-01

The fatigue behaviour of vacuum plasma sprayed (VPS) and detonation gun sprayed (DGUN) hydroxyapatite coatings on titanium substrates has been compared in air and in buffered Ringer's solution. There was an increase in the surface microcracking and bulk porosity of both types of coating tested in air. After 1 million cycles in Ringer's solution the VPS coatings had completely delaminated from their substrates. In contrast the DGUN coatings retained their integrity when tested up to 10 million cycles but were beginning to show signs of delamination at the interface.

Facile preparation of polymer microspheres and fibers with a hollow core and porous shell for oil adsorption and oil/water separation

NASA Astrophysics Data System (ADS)

Gao, Jiefeng; Song, Xin; Huang, Xuewu; Wang, Ling; Li, Bei; Xue, Huaiguo

2018-05-01

Non-solvent assisted electrospinning was proposed for fabricating Polymethylmethacrylate (PMMA) microspheres and fibers with a hollow core and porous shell, which could be used for oil adsorption and oil/water separation. Propanediol was chosen as the non-solvent because of its high surface tension and viscosity as well as large phase separation tendency with polymer, which was beneficial to the formation of both the hollow core and porous shell during the electrospinning. With the increase of the polymer solution concentration, the microsphere gradually evolved to the bead-on-string geometry and finally to a continuous fiber form, indicating the transition from electro-spraying to electrospinning. The hollow core and dense surface pores enhanced the hydrophobicity, oleophilicity, permeability, and specific surface area of the fibers, and hence imparted the fibrous mat a high oil adsorption capacity. When the porous hollow microspheres were electro-sprayed onto the stainless steel mesh followed by the PDMS modification, the modified mesh became super-hydrophobic and super-oleophilic with the contact angle of 153° and sliding angle of 4°. The as-prepared mesh showed rapid oil/water separation with high efficiency and excellent recycling performance. The flux for separation of oil/water mixture could reach as high as 11,000 L m-2 h-1. This facile non-solvent assisted electrospinning method provides a new avenue for preparation of multifunctional porous materials which possess potential applications in large-scale oil/water separation.

Thin layer chromatography coupled to paper spray ionization mass spectrometry for cocaine and its adulterants analysis.

PubMed

De Carvalho, Thays C; Tosato, Flavia; Souza, Lindamara M; Santos, Heloa; Merlo, Bianca B; Ortiz, Rafael S; Rodrigues, Rayza R T; Filgueiras, Paulo R; França, Hildegardo S; Augusti, Rodinei; Romão, Wanderson; Vaz, Boniek G

2016-05-01

Thin layer chromatography (TLC) is a simple and inexpensive type of chromatography that is extensively used in forensic laboratories for drugs of abuse analysis. In this work, TLC is optimized to analyze cocaine and its adulterants (caffeine, benzocaine, lidocaine and phenacetin) in which the sensitivity (visual determination of LOD from 0.5 to 14mgmL(-1)) and the selectivity (from the study of three different eluents: CHCl3:CH3OH:HCOOHglacial (75:20:5v%), (C2H5)2O:CHCl3 (50:50v%) and CH3OH:NH4OH (100:1.5v%)) were evaluated. Aiming to improve these figures of merit, the TLC spots were identified and quantified (linearity with R(2)>0.98) by the paper spray ionization mass spectrometry (PS-MS), reaching now lower LOD values (>1.0μgmL(-1)). The method developed in this work open up perspective of enhancing the reliability of traditional and routine TLC analysis employed in the criminal expertise units. Higher sensitivity, selectivity and rapidity can be provided in forensic reports, besides the possibility of quantitative analysis. Due to the great simplicity, the PS(+)-MS technique can also be coupled directly to other separation techniques such as the paper chromatography and can still be used in analyses of LSD blotter, documents and synthetic drugs. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Highly-hermetic feedthrough fiber pigtailed circular TO-can electro-optic sensor for avionics applications

NASA Astrophysics Data System (ADS)

Lauzon, Jocelyn; Leduc, Lorrain; Bessette, Daniel; Bélanger, Nicolas

2012-06-01

Electro-optic sensors made of lasers or photodetectors assemblies can be associated with a window interface. In order to use these sensors in an avionics application, this interface has to be set on the periphery of the aircraft. This creates constraints on both the position/access of the associated electronics circuit card and the aircraft fuselage. Using an optical fiber to guide the light signal to a sensor being situated inside the aircraft where electronics circuit cards are deployed is an obvious solution that can be readily available. Fiber collimators that adapt to circular TO-can type window sensors do exist. However, they are bulky, add weight to the sensor and necessitate regular maintenance of the optical interface since both the sensor window and the collimator end-face are unprotected against contamination. Such maintenance can be complex since the access to the electronics circuit card, where the sensor is sitting, is usually difficult. This interface alignment can also be affected by vibrations and mechanical shocks, thus impacting sensor performances. As a solution to this problem, we propose a highly-hermetic feedthrough fiber pigtailed circular TO-can package. The optical element to optical fiber interface being set inside the hermetic package, there is no risk of contamination and thus, such a component does not require any maintenance. The footprint of these sensors being identical to their window counterparts, they offer drop-in replacement opportunities. Moreover, we have validated such packaged electro-optic sensors can be made to operate between -55 to 115°C, sustain 250 temperature cycles, 1500G mechanical shocks, 20Grms random vibrations without any performance degradations. Their water content is much smaller than the 0.5% limit set by MIL-STD-883, Method 1018. They have also been verified to offer a fiber pigtail strain relief resistance over 400g. Depending on the electronics elements inside these sensors, they can be made to have a MTBF over 50 000h at 100°C.

Determination of 5-hydroxy-N-methyl-2-pyrrolidone and 2-hydroxy-N-methylsuccinimide in human plasma and urine using liquid chromatography-electrospray tandem mass spectrometry.

PubMed

Carnerup, M A; Akesson, B; Jönsson, B A

2001-09-15

A method for simultaneous determination of 5-hydroxy-N-methyl-2-pyrrolidone (5-HNMP) and 2-hydroxy-N-methylsuccinimide (2-HMSI) was developed. These compounds are metabolites from N-methyl-2-pyrrolidone (NMP), a powerful and widely used organic solvent. 5-HNMP and 2-HMSI were purified from plasma and urine by solid-phase extraction using Isolute ENV+ columns, and analysed by liquid chromatography coupled to a mass spectrometer fitted with an atmospheric pressure turbo ion spray ionisation interface in the positive ion mode. The method was validated for plasma and urine concentrations from 0.12 to 25 microg/ml. The recoveries for 5-HNMP and 2-HMSI in plasma were 99 and 98%, respectively, and in urine 111 and 106%, respectively. For 5-HNMP and 2-HMSI, the within-day precision in plasma was 1-4 and 3-6%, respectively, and in urine 2-12 and 3-10%, respectively. The corresponding data for the between-day precision was 5 and 3-6%, respectively, and 4-6 and 7-8%, respectively. The detection limit for 5-HNMP was 4 ng/ml in plasma and 120 ng/ml in urine. For 2-HMSI, it was 5 ng/ml in plasma and 85 ng/ml in urine. The method is applicable for analysis of plasma and urine samples from workers exposed to NMP.

Characterization of a mixture of lobster digestive cysteine proteinases by ionspray mass spectrometry and tryptic mapping with LC--MS and LC--MS--MS

NASA Astrophysics Data System (ADS)

Thibault, P.; Pleasance, S.; Laycock, M. V.; Mackay, R. M.; Boyd, R. K.

1991-12-01

An inseparable mixture of two cysteine proteinases, isolated from the digestive tract of the American lobster, was investigated by ionspray mass spectrometry (ISP-MS), using a combination of infusion of intact proteins with on-line liquid chromatography--mass spectrometry (LC--MS) and LC--MS--MS analyses of tryptic digests. These data were interpreted by comparisons with predictions from results of molecular cloning of cysteine-proteinase-encoding messenger RNA sequences previously isolated from the lobster hepatopancreas. Investigations of the numbers of free thiol groups and of disulfide bonds were made by measuring the molecular weights of the alkylated proteins with and without prior reduction of disulfide bonds, and comparison with the corresponding data for the native proteins. Identification of tyrptic fragment peptides containing cysteine residues was facilitated by comparing LC--MS analyses of tryptic digests of denatured and of denatured and alkylated proteins, since such tryptic peptides are subject to shifts in both mass and retention time upon reduction and alkylation. Confirmation of amino acid sequences was obtained from fragment ion spectra of each tryptic peptide (alkylated or not) as it eluted from the column. Acquisition of such on-line LC--MS data was possible through use of the entire effluent from a standard 1 mm high performance liquid chromatography (HPLC) column by an IonsSpray® LC--MS interface (pneumatically assisted electrospray).

Electro-optical backplane demonstrator with integrated multimode gradient-index thin glass waveguide panel

NASA Astrophysics Data System (ADS)

Schröder, Henning; Brusberg, Lars; Pitwon, Richard; Whalley, Simon; Wang, Kai; Miller, Allen; Herbst, Christian; Weber, Daniel; Lang, Klaus-Dieter

2015-03-01

Optical interconnects for data transmission at board level offer increased energy efficiency, system density, and bandwidth scalability compared to purely copper driven systems. We present recent results on manufacturing of electrooptical printed circuit board (PCB) with integrated planar glass waveguides. The graded index multi-mode waveguides are patterned inside commercially available thin-glass panels by performing a specific ion-exchange process. The glass waveguide panel is embedded within the layer stack-up of a PCB using proven industrial processes. This paper describes the design, manufacture, assembly and characterization of the first electro-optical backplane demonstrator based on integrated planar glass waveguides. The electro-optical backplane in question is created by laminating the glass waveguide panel into a conventional multi-layer electronic printed circuit board stack-up. High precision ferrule mounts are automatically assembled, which will enable MT compliant connectors to be plugged accurately to the embedded waveguide interfaces on the glass panel edges. The demonstration platform comprises a standardized sub-rack chassis and five pluggable test cards each housing optical engines and pluggable optical connectors. The test cards support a variety of different data interfaces and can support data rates of up to 32 Gb/s per channel.

The electrochemical reduction processes of solid compounds in high temperature molten salts.

PubMed

Xiao, Wei; Wang, Dihua

2014-05-21

Solid electrode processes fall in the central focus of electrochemistry due to their broad-based applications in electrochemical energy storage/conversion devices, sensors and electrochemical preparation. The electrolytic production of metals, alloys, semiconductors and oxides via the electrochemical reduction of solid compounds (especially solid oxides) in high temperature molten salts has been well demonstrated to be an effective and environmentally friendly process for refractory metal extraction, functional materials preparation as well as spent fuel reprocessing. The (electro)chemical reduction of solid compounds under cathodic polarizations generally accompanies a variety of changes at the cathode/melt electrochemical interface which result in diverse electrolytic products with different compositions, morphologies and microstructures. This report summarizes various (electro)chemical reactions taking place at the compound cathode/melt interface during the electrochemical reduction of solid compounds in molten salts, which mainly include: (1) the direct electro-deoxidation of solid oxides; (2) the deposition of the active metal together with the electrochemical reduction of solid oxides; (3) the electro-inclusion of cations from molten salts; (4) the dissolution-electrodeposition process, and (5) the electron hopping process and carbon deposition with the utilization of carbon-based anodes. The implications of the forenamed cathodic reactions on the energy efficiency, chemical compositions and microstructures of the electrolytic products are also discussed. We hope that a comprehensive understanding of the cathodic processes during the electrochemical reduction of solid compounds in molten salts could form a basis for developing a clean, energy efficient and affordable production process for advanced/engineering materials.

Middle School Science Notes.

ERIC Educational Resources Information Center

School Science Review, 1979

1979-01-01

Included is information regarding: student construction of Newton's Discs to demonstrate color and of paper helicopters to encourage inquiry; improvising an apparatus demonstrating pressure between two bubbles; animal behavior experiments involving woodlice; two experiments using electronics freezer spray; chromatography of dyes; leaf keys; an…

The effect of handpiece spray patterns on cutting efficiency.

PubMed

Siegel, Sharon C; von Fraunhofer, J Anthony

2002-02-01

High-speed handpieces' spray ports direct coolant at the cutting interface. The authors evaluated the effect of the number of ports and their positions on cutting rates, or CRs. The authors performed cutting studies on a machinable ceramic block using an established testing regimen. One-port, three-port and four-port handpieces from one manufacturer were operated at maximum torque and rotation speed under a water flow of 25 milliliters per minute. The authors made 6-millimeter long edge and groove cuts in 13-mm cross-section blocks using six medium-grit diamond burs for each handpiece. Each bur cut a total of 78 mm. The authors determined CR as the time to transect the block and analyzed the data by two-way analysis of variance with post hoc Scheffé tests. CRs varied by the type of cut and the number of spray ports. No differences were found in CRs for the three handpieces during edge cutting. The one-port handpiece cut significantly slower (P < .001) than did the three- and four-port handpieces during groove cutting. The data indicate that the number of handpiece spray ports, and their positioning relative to the bur affect water supply to the cutting interface and, consequently, the CR under these study conditions. Optimal cutting efficiency requires good coolant access, especially within restricted areas. A multiple-port handpiece may be advantageous when preparing the interproximal region for a crown or a proximal box, owing to the better water spray pattern. Dentists should consider the influence of the number of spray ports when selecting handpieces for cutting procedures.

Interface Modeling for Electro-Osmosis in Subgrade Structures

DTIC Science & Technology

2004-12-01

aggregate and different clays ( kaolinite , montmorillonite , limestone and quartz sands) created to simulate below grade structures. A direct current 30...Quartz Sand 100 Sieve Ca Montmorillonite Na Montmorillonite Kaolinite The test setup used a 0.45 water to cement ratio concrete cylinder... Kaolinite cell Figure 4. Measured pH for Concrete and Na Montmorillonite cell 4 Scaling occurred at the interface between the anode

Transformation characteristics of refractory pollutants in plugboard wastewater by an optimal electrocoagulation and electro-Fenton process.

PubMed

Zhao, Xu; Zhang, Baofeng; Liu, Huijuan; Chen, Fayuan; Li, Angzhen; Qu, Jiuhui

2012-05-01

The treatment of the plugboard wastewater was performed by an optimal electrocoagulation and electro-Fenton. The organic components with suspended fractions accounting for 30% COD were preferably removed via electrocoagulation at initial 5 min. In contrast, the removal efficiency was increased to 76% with the addition of H(2)O(2). The electrogenerated Fe(2+) reacts with H(2)O(2) and leads to the generation of (·)OH, which is responsible for the higher COD removal. However, overdosage H(2)O(2) will consume (·)OH generated in the electro-Fenton process and lead to the low COD removal. The COD removal efficiency decreased with the increased pH. The concentration of Fe(2+) ions was dependent on the solution pH, H(2)O(2) dosage and current density. The changes of organic characteristics in coagulation and oxidation process were differenced and evaluated using gel permeation chromatography, fluorescence excitation-emission scans and Fourier transform infrared spectroscopy. The fraction of the wastewater with aromatic structure and large molecular weight was decomposed into aliphatic structure and small molecular weight fraction in the electro-Fenton process. Copyright © 2012. Published by Elsevier Ltd.

Formation of interfacial compounds and the effects on stripping behaviors of a cold-sprayed Zn-Al coating on interstitial-free steel

NASA Astrophysics Data System (ADS)

Liang, Y. L.; Wang, Z. B.; Zhang, J. B.; Lu, K.

2015-06-01

By means of cold spray, a Zn-Al coating was successfully deposited on an interstitial-free (IF) steel sheet. The formation of interfacial compounds between the coating and the IF steel was studied during diffusion annealing at 400 °C. And its correlations with the stripping behaviors of the coating were investigated by using a three-point bending method. The results showed that Fe-Zn and Fe-Al-Zn compounds begin to form at the coating/substrate interface after an annealing duration of 60 min, and the stripping resistance increases slightly before that duration and then decreases significantly by further increasing annealing duration. The enhanced stripping resistance at the earlier stage might be due to the modifications of microstructure and deformation compatibility of the sprayed coating, while the decreased stripping resistance at the later stage is related to the high stress concentration at the interface of the formed brittle Fe-Al-Zn phase and the Zn-Al coating.

Simulation of fundamental atomization mechanisms in fuel sprays

NASA Technical Reports Server (NTRS)

Childs, Robert, E.; Mansour, Nagi N.

1988-01-01

Growth of instabilities on the liquid/gas interface in the initial region of fuel sprays is studied by means of numerical simulations. The simulations are based on solutions of the variable-density incompressible Navier-Stokes equations, which are obtained with a new numerical algorithm. The simulations give good agreement with analytical results for the instabilities on a liquid cylinder induced by surface tension and wind-induced instabilities. The effects of boundary layers on the wind-induced instabilities are investigated. It is found that a boundary layer reduces the growth rate for a single interface, and a comparison with inviscid theory suggests that boundary layer effects may be significantly more important than surface tension effects. The results yield a better estimate than inviscid theory for the drop sizes as reported for diesel sprays. Results for the planar jet show that boundary layer effects hasten the growth of Squire's 'symmetric' mode, which is responsible for jet disintegration. This result helps explain the rapid atomization which occurs in swirl and air-blast atomizers.

Spray-coating process in preparing PTFE-PPS composite super-hydrophobic coating

NASA Astrophysics Data System (ADS)

Weng, Rui; Zhang, Haifeng; Liu, Xiaowei

2014-03-01

In order to improve the performance of a liquid-floated rotor micro-gyroscope, the resistance of the moving interface between the rotor and the floating liquid must be reduced. Hydrophobic treatment can reduce the frictional resistance between such interfaces, therefore we proposed a method to prepare a poly-tetrafluoroethylene (PTFE)-poly-phenylene sulphide (PPS) composite super-hydrophobic coating, based on a spraying process. This method can quickly prepare a continuous, uniform PTFE-PPS composite super-hydrophobic surface on a 2J85 material. This method can be divided into three steps, namely: pre-treatment; chemical etching; and spraying. The total time for this is around three hours. When the PTFE concentration is 4%, the average contact angle of the hydrophobic coating surface is 158°. If silicon dioxide nanoparticles are added, this can further improve the adhesion and mechanical strength of the super-hydrophobic composite coating. The maximum average contact angle can reach as high as 164° when the mass fraction of PTFE, PPS and silicon dioxide is 1:1:1.

Foliar Essential Oil Glands of Eucalyptus Subgenus Eucalyptus (Myrtaceae) Are a Rich Source of Flavonoids and Related Non-Volatile Constituents

PubMed Central

Nicolle, Dean; Woodrow, Ian E.

2016-01-01

The sub-dermal secretory cavities (glands) embedded within the leaves of Eucalyptus (Myrtaceae) were once thought to be the exclusive repositories of monoterpene and sesquiterpene oils. Recent research has debunked this theory and shown that abundant non-volatile compounds also occur within foliar glands. In particular, glands of four species in subgenus Eucalyptus contain the biologically active flavanone pinocembrin. Pinocembrin shows great promise as a pharmaceutical and is predominantly plant-sourced, so Eucalyptus could be a potential commercial source of such compounds. To explore this we quantified and assessed the purity of pinocembrin in glands of 11 species of E. subg. Eucalyptus using Electro-Spray Ionisation Liquid Chromatography Mass Spectrometry of acetonitrile extracts and Gas Chromatography Mass Spectrometry analyses of hexane extracts of isolated glands which were free from other leaf tissues. Our results showed that the glands of subgenus Eucalyptus contain numerous flavanones that are structurally related to pinocembrin and often present in much greater abundance. The maximum concentration of pinocembrin was 2 mg g-1 dry leaf found in E. stellulata, whereas that of dimethylpinocembrin (5,7-dimethoxyflavanone) was 10 mg g-1 in E. oreades and that of pinostrobin (5-hydroxy-7-methoxyflavanone) was 12 mg g-1 in E. nitida. We also found that the flavanones are exclusively located within the foliar glands rather than distributed throughout leaf tissues. The flavanones differ from the non-methylated pinocembrin in the degree and positions of methylation. This finding is particularly important given the attractiveness of methylated flavonoids as pharmaceuticals and therapeutics. Another important finding was that glands of some members of the subgenus also contain flavanone O-glucosides and flavanone-β-triketone conjugates. In addition, glands contain free β-triketones, β-triketone heterodimers and chromone C-glucosides. Therefore, the foliar glands of this taxonomically distinct group of plants are a rich source of a range of flavonoids and other biologically active compounds with great commercial potential. PMID:26977933

Foliar Essential Oil Glands of Eucalyptus Subgenus Eucalyptus (Myrtaceae) Are a Rich Source of Flavonoids and Related Non-Volatile Constituents.

PubMed

Goodger, Jason Q D; Seneratne, Samiddhi L; Nicolle, Dean; Woodrow, Ian E

2016-01-01

The sub-dermal secretory cavities (glands) embedded within the leaves of Eucalyptus (Myrtaceae) were once thought to be the exclusive repositories of monoterpene and sesquiterpene oils. Recent research has debunked this theory and shown that abundant non-volatile compounds also occur within foliar glands. In particular, glands of four species in subgenus Eucalyptus contain the biologically active flavanone pinocembrin. Pinocembrin shows great promise as a pharmaceutical and is predominantly plant-sourced, so Eucalyptus could be a potential commercial source of such compounds. To explore this we quantified and assessed the purity of pinocembrin in glands of 11 species of E. subg. Eucalyptus using Electro-Spray Ionisation Liquid Chromatography Mass Spectrometry of acetonitrile extracts and Gas Chromatography Mass Spectrometry analyses of hexane extracts of isolated glands which were free from other leaf tissues. Our results showed that the glands of subgenus Eucalyptus contain numerous flavanones that are structurally related to pinocembrin and often present in much greater abundance. The maximum concentration of pinocembrin was 2 mg g-1 dry leaf found in E. stellulata, whereas that of dimethylpinocembrin (5,7-dimethoxyflavanone) was 10 mg g-1 in E. oreades and that of pinostrobin (5-hydroxy-7-methoxyflavanone) was 12 mg g-1 in E. nitida. We also found that the flavanones are exclusively located within the foliar glands rather than distributed throughout leaf tissues. The flavanones differ from the non-methylated pinocembrin in the degree and positions of methylation. This finding is particularly important given the attractiveness of methylated flavonoids as pharmaceuticals and therapeutics. Another important finding was that glands of some members of the subgenus also contain flavanone O-glucosides and flavanone-β-triketone conjugates. In addition, glands contain free β-triketones, β-triketone heterodimers and chromone C-glucosides. Therefore, the foliar glands of this taxonomically distinct group of plants are a rich source of a range of flavonoids and other biologically active compounds with great commercial potential.

Evaluation of a commercial electro-kinetically pumped sheath-flow nanospray interface coupled to an automated capillary zone electrophoresis system.

PubMed

Peuchen, Elizabeth H; Zhu, Guije; Sun, Liangliang; Dovichi, Norman J

2017-03-01

Capillary zone electrophoresis-electrospray ionization-mass spectrometry (CZE-ESI-MS) is attracting renewed attention for proteomic and metabolomic analysis. An important reason for this interest is the maturation and commercialization of interfaces for coupling CZE with ESI-MS. One of these interfaces is an electro-kinetically pumped sheath flow nanospray interface developed by the Dovichi group, in which a very low sheath flow is generated based on electroosmosis within a glass emitter. CMP Scientific has commercialized this interface as the EMASS-II ion source. In this work, we compared the performance of the EMASS-II ion source with our in-house system. The performance of the systems is equivalent. We also coupled the EMASS-II ion source with a PrinCE Next|480 capillary electrophoresis autosampler and an Orbitrap mass spectrometer, and analyzed this system's performance in terms of sensitivity, reproducibility, and separation performance for separation of tryptic digests, intact proteins, and amino acids. The system produced reproducible analysis of BSA digest; the RSDs of peptide intensity and migration time across 24 runs were less than 20 and 6%, respectively. The system produced a linear calibration curve of intensity across a 30-fold range of tryptic digest concentration. The combination of a commercial autosampler and electrospray interface efficiently separated amino acids, peptides, and intact proteins, and only required 5 μL of sample for analysis. Graphical Abstract The commercial and locally constructed versions of the interface provide similar numbers of protein identifications from a Xenopus laevis fertilized egg digest.

Assessing Reliability of Cold Spray Sputter Targets in Photovoltaic Manufacturing

NASA Astrophysics Data System (ADS)

Hardikar, Kedar; Vlcek, Johannes; Bheemreddy, Venkata; Juliano, Daniel

2017-10-01

Cold spray has been used to manufacture more than 800 Cu-In-Ga (CIG) sputter targets for deposition of high-efficiency photovoltaic thin films. It is a preferred technique since it enables high deposit purity and transfer of non-equilibrium alloy states to the target material. In this work, an integrated approach to reliability assessment of such targets with deposit weight in excess of 50 lb. is undertaken, involving thermal-mechanical characterization of the material in as-deposited condition, characterization of the interface adhesion on cylindrical substrate in as-deposited condition, and developing means to assess target integrity under thermal-mechanical loads during the physical vapor deposition (PVD) sputtering process. Mechanical characterization of cold spray deposited CIG alloy is accomplished through the use of indentation testing and adaptation of Brazilian disk test. A custom lever test was developed to characterize adhesion along the cylindrical interface between the CIG deposit and cylindrical substrate, overcoming limitations of current standards. A cohesive zone model for crack initiation and propagation at the deposit interface is developed and validated using the lever test and later used to simulate the potential catastrophic target failure in the PVD process. It is shown that this approach enables reliability assessment of sputter targets and improves robustness.

Cold Spray Repair of Martensitic Stainless Steel Components

NASA Astrophysics Data System (ADS)

Faccoli, M.; Cornacchia, G.; Maestrini, D.; Marconi, G. P.; Roberti, R.

2014-12-01

The possibility of using cold spray as repair technique of martensitic stainless steel components was evaluated through laboratory investigations. An austenitic stainless steel feedstock powder was chosen, instead of soft metals powders like nickel, copper, or aluminum, used for repairing components made in light alloy or cast iron. The present study directly compares the microstructure, the residual stresses, and the micro-hardness of repairs obtained by cold spray and by TIG welding, that is commonly used as repair technique in large steel components. XRD and optical metallographic analysis of the repairs showed that cold spray offers some advantages, inducing compressive residual stresses in the repair and avoiding alterations of the interface between repair and base material. For these reasons, a heat treatment after the cold spray repair is not required to restore the base material properties, whereas a post-weld heat treatment is needed after the welding repair. Cold spray repair also exhibits a higher micro-hardness than the welding repair. In addition, the cavitation erosion resistance of a cold spray coating was investigated through ultrasonic cavitation tests, and the samples worn surfaces were observed by scanning electron microscopy.

Active Control of Charge Density Waves at Degenerate Semiconductor Interfaces

NASA Astrophysics Data System (ADS)

Vinnakota, Raj; Genov, Dentcho

We present numerical modeling of an active electronically controlled highly confined charge-density waves, i.e. surface plasmon polaritons (SPPs) at the metallurgic interfaces of degenerate semiconductor materials. An electro-optic switching element for fully-functional plasmonic circuits based on p-n junction semiconductor Surface Plasmon Polariton (SPP) waveguide is shown. Two figures of merits are introduced and parametric study has been performed identifying the device optimal operation range. The Indium Gallium Arsenide (In0.53Ga0.47As) is identified as the best semiconductor material for the device providing high optical confinement, reduced system size and fast operation. The electro-optic SPP switching element is shown to operate at signal modulation up to -24dB and switching rates surpassing 100GHz, thus potentially providing a new pathway toward bridging the gap between electronic and photonic devices. The current work is funded by the NSF EPSCoR CIMM project under award #OIA-1541079.

Optical to optical interface device

NASA Technical Reports Server (NTRS)

Oliver, D. S.; Vohl, P.; Nisenson, P.

1972-01-01

The development, fabrication, and testing of a preliminary model of an optical-to-optical (noncoherent-to-coherent) interface device for use in coherent optical parallel processing systems are described. The developed device demonstrates a capability for accepting as an input a scene illuminated by a noncoherent radiation source and providing as an output a coherent light beam spatially modulated to represent the original noncoherent scene. The converter device developed under this contract employs a Pockels readout optical modulator (PROM). This is a photosensitive electro-optic element which can sense and electrostatically store optical images. The stored images can be simultaneously or subsequently readout optically by utilizing the electrostatic storage pattern to control an electro-optic light modulating property of the PROM. The readout process is parallel as no scanning mechanism is required. The PROM provides the functions of optical image sensing, modulation, and storage in a single active material.

Recent highlights in electro-driven separations- selected applications of alkylthiol gold nanoparticles in capillary electrophoresis and capillary electro-chromatography.

PubMed

Guihen, Elizabeth

2017-09-01

To date, alkylthiol gold nanoparticles (AuNPs) have been widely used in electro-chromatographic separation techniques as a viable alternative to traditional stationary phases. This is mainly due to their stability, chemical inertness, ease of functionality, increased phase ratio, ability to form self-assembled monolayers. They also yield versatile stationary phases with highly specific targeted functionalities. At the nanoscale region, the chemical and physical properties of a molecule display different attributes to that of the parent molecules or material, hence these features can be harnessed in electro-driven chromatographic separations. Application areas illustrating the use of AuNPs in separation science continue to grow and expand to cover many different kinds of analysis. The last decade has witnessed a successful trend in miniaturisation of chemical separation systems toward the micro and nanoscale ranges. Nanoparticle-based stationary phases fit well with performing chemical separations on microfluidic and capillary platforms. In this review the theory of the use of alkylthiol gold nanoparticles in electro-chromatographic driven separation methods will be discussed. This will be followed by details of recent and selected applications showing alkylthiol gold nanoparticles in capillary electrophoretic and open-tubular electro-chromatographic separations. This review will focus solely on alkylthiol based gold nanoparticles, therefore other kinds of chemical moieties bonded to gold nanoparticles are outside the scope of this review. Finally the future outlook of this exciting technology will be outlined in some detail in the final section. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Base-metal saturation of refractory carbide coatings produced by enhanced ceramic jets in electrothermally exploded powder spray

NASA Astrophysics Data System (ADS)

Tamura, Hideki; Itaya, Masanobu

2000-09-01

Tungsten carbide and tantalum carbide were sprayed onto substrates of mild steel by the electrothermally exploded powder spray (ELTEPS) process. High-speed x-ray radiography revealed that tungsten-carbide jets of molten particles guided inside a nozzle exhibited denser flow than unguided jets at the substrate. The velocity of the jet was approximately 800 m/s at the early stage of jetting. The ceramic coatings obtained from the guided spray consisted of carbides of a few to tens of micrometers in size, which were saturated by the base metal up to the top of the coating. The coatings exhibited diffusion of the sprayed ceramics and base metal at the interface of the deposit and substrate. The enhancement of the jet flow formed a microstructure of the ceramic coating, which was saturated by the base metal even without post heat treatment.

Detailed investigation of a vaporising fuel spray. Part 1: Experimental investigation of time averaged spray

NASA Technical Reports Server (NTRS)

Yule, A. J.; Seng, C. A.; Boulderstone, R.; Ungut, A.; Felton, P. G.; Chigier, N. A.

1980-01-01

A laser tomographic light scattering technique provides rapid and accurate high resolution measurements of droplet sizes, concentrations, and vaporization. Measurements using a computer interfaced thermocouple are presented and it is found that the potential exists for separating gas and liquid temperature measurements and diagnosing local spray density by in situ analysis of the response characteristics of the thermocouple. The thermocouple technique provides a convenient means for measuring mean gas velocity in both hot and cold two phase flows. The experimental spray is axisymmetric and has carefully controlled initial and boundary conditions. The flow is designed to give relatively insignificant transfer of momentum and mass from spray to air flow. The effects of (1) size-dependent droplet dispersion by the turbulence, (2) the initial spatial segregation of droplet sizes during atomization, and (3) the interaction between droplets and coherent large eddies are diagnosed.

A Computer-Interfaced Drop Counter as an Inexpensive Fraction Collector for Column Chromatography

ERIC Educational Resources Information Center

Nash, Barbara T.

2008-01-01

A computer-interfaced drop counter is described that serves as an inexpensive alternative to a fraction collector for column chromatography experiments. Undergraduate biochemistry laboratories frequently do not have the budget to purchase fraction collectors. Protocols that call for the manual measurement of fraction volumes as well as the manual…

Self-Pressurization and Spray Cooling Simulations of the Multipurpose Hydrogen Test Bed (MHTB) Ground-Based Experiment

NASA Technical Reports Server (NTRS)

Kartuzova, O.; Kassemi, M.; Agui, J.; Moder, J.

2014-01-01

This paper presents a CFD (computational fluid dynamics) model for simulating the self-pressurization of a large scale liquid hydrogen storage tank. In this model, the kinetics-based Schrage equation is used to account for the evaporative and condensing interfacial mass flows. Laminar and turbulent approaches to modeling natural convection in the tank and heat and mass transfer at the interface are compared. The flow, temperature, and interfacial mass fluxes predicted by these two approaches during tank self-pressurization are compared against each other. The ullage pressure and vapor temperature evolutions are also compared against experimental data obtained from the MHTB (Multipuprpose Hydrogen Test Bed) self-pressurization experiment. A CFD model for cooling cryogenic storage tanks by spraying cold liquid in the ullage is also presented. The Euler- Lagrange approach is utilized for tracking the spray droplets and for modeling interaction between the droplets and the continuous phase (ullage). The spray model is coupled with the VOF (volume of fluid) model by performing particle tracking in the ullage, removing particles from the ullage when they reach the interface, and then adding their contributions to the liquid. Droplet ullage heat and mass transfer are modeled. The flow, temperature, and interfacial mass flux predicted by the model are presented. The ullage pressure is compared with experimental data obtained from the MHTB spray bar mixing experiment. The results of the models with only droplet/ullage heat transfer and with heat and mass transfer between the droplets and ullage are compared.

Pt-Pd bimetallic nanoparticles on MWCNTs: catalyst for hydrogen peroxide electrosynthesis

NASA Astrophysics Data System (ADS)

Félix-Navarro, R. M.; Beltrán-Gastélum, M.; Salazar-Gastélum, M. I.; Silva-Carrillo, C.; Reynoso-Soto, E. A.; Pérez-Sicairos, S.; Lin, S. W.; Paraguay-Delgado, F.; Alonso-Núñez, G.

2013-08-01

Bimetallic nanoparticles of Pt-Pd were deposited by the microemulsion method on a multiwall carbon nanotube (MWCNTs) to obtain a Pt-Pd/MWCNTs for electrocatalytic reduction of O2 to H2O2. The activity and selectivity of the catalyst was determined qualitatively by the rotating disk electrode method in acidic medium. The catalyst was spray-coated onto a reticulated vitreous carbon substrate and quantitatively was tested in bulk electrolysis for 20 min under potentiostatic conditions (0.5 V vs Ag/AgCl) in a 0.5 M H2SO4 electrolyte using dissolved O2. The bulk electrolysis experiments show that the Pt-Pd/MWCNTs catalyst is more efficient for H2O2 electrogeneration than a MWCNTs catalyst. Nitrobenzene degradation by electrogenerated H2O2 alone and Electro-Fenton process were also tested. Our results show that both processes decompose nitrobenzene, but the Electro-Fenton process does it more efficiently. The prepared nanoparticulated catalyst shows a great potential in environmental applications.

Multi-scale theory-assisted nano-engineering of plasmonic-organic hybrid electro-optic device performance

NASA Astrophysics Data System (ADS)

Elder, Delwin L.; Johnson, Lewis E.; Tillack, Andreas F.; Robinson, Bruce H.; Haffner, Christian; Heni, Wolfgang; Hoessbacher, Claudia; Fedoryshyn, Yuriy; Salamin, Yannick; Baeuerle, Benedikt; Josten, Arne; Ayata, Masafumi; Koch, Ueli; Leuthold, Juerg; Dalton, Larry R.

2018-02-01

Multi-scale (correlated quantum and statistical mechanics) modeling methods have been advanced and employed to guide the improvement of organic electro-optic (OEO) materials, including by analyzing electric field poling induced electro-optic activity in nanoscopic plasmonic-organic hybrid (POH) waveguide devices. The analysis of in-device electro-optic activity emphasizes the importance of considering both the details of intermolecular interactions within organic electro-optic materials and interactions at interfaces between OEO materials and device architectures. Dramatic improvement in electro-optic device performance-including voltage-length performance, bandwidth, energy efficiency, and lower optical losses have been realized. These improvements are critical to applications in telecommunications, computing, sensor technology, and metrology. Multi-scale modeling methods illustrate the complexity of improving the electro-optic activity of organic materials, including the necessity of considering the trade-off between improving poling-induced acentric order through chromophore modification and the reduction of chromophore number density associated with such modification. Computational simulations also emphasize the importance of developing chromophore modifications that serve multiple purposes including matrix hardening for enhanced thermal and photochemical stability, control of matrix dimensionality, influence on material viscoelasticity, improvement of chromophore molecular hyperpolarizability, control of material dielectric permittivity and index of refraction properties, and control of material conductance. Consideration of new device architectures is critical to the implementation of chipscale integration of electronics and photonics and achieving the high bandwidths for applications such as next generation (e.g., 5G) telecommunications.

Development of a low-flow multiplexed interface for capillary electrophoresis/electrospray ion trap mass spectrometry using sequential spray.

PubMed

Chen, Chao-Jung; Li, Fu-An; Her, Guor-Rong

2008-05-01

A multiplexed CE-MS interface using four low-flow sheath liquid ESI sprayers has been developed. Because of the limited space between the low-flow sprayers and the entrance aperture of the ESI source, multichannel analysis is difficult using conventional rotating plate approaches. Instead, a multiplexed low-flow system was achieved by applying an ESI potential sequentially to the four low-flow sprayers, resulting in only one sprayer being sprayed at any given time. The synchronization of the scan event and the voltage relays was accomplished by using the data acquisition signal from the IT mass spectrometer. This synchronization resulted in the ESI voltage being sequentially applied to each of the four sprayers according to the corresponding scan event. With this design, a four-fold increase in analytical throughput was achieved. Because of the use of low-flow interfaces, this multiplexed system has superior sensitivity than a rotating plate design using conventional sheath liquid interfaces. The multiplexed design presented has the potential to be applied to other low-flow multiplexed systems, such as multiplexed capillary LC and multiplexed CEC.

Microstructure and mechanical behavior of Zr substrates coated with FeCrAl and Mo by cold-spraying

NASA Astrophysics Data System (ADS)

Park, Dong Jun; Kim, Hyun Gil; Jung, Yang Il; Park, Jung Hwan; Yang, Jae Ho; Koo, Yang Hyun

2018-06-01

FeCrAl and Mo layers were cold-sprayed onto a Zr surface, with the Mo layer introduced between the FeCrAl coating and the Zr matrix preventing high-temperature interdiffusion. Microstructural characterization of the first-deposited Mo layer and the Zr matrix immediately below the Mo/Zr interface was performed using transmission electron microscopy, and near-interface elemental distributions were obtained using energy-dispersive X-ray spectroscopy. The deformation of the coated Mo powder induced the formation of microbands and mechanically interlocked nanoscale structures. The mechanical behavior of Zr with a coating layer was compared with those characteristic of conventional Zr samples. The coated sample showed smaller strength reduction in the test conducted at elevated temperature. The hardness and fracture morphology of the Zr matrix near the interface region were investigated to determine the effect of impacting Mo particles on the matrix microstructure. The enhanced hardness and cleavage fracture morphology of the Zr matrix immediately below the Mo/Zr interface indicated the occurrence of localized deformation owing to Mo particle impact.

Determination of residual acetone and acetone related impurities in drug product intermediates prepared as Spray Dried Dispersions (SDD) using gas chromatography with headspace autosampling (GCHS).

PubMed

Quirk, Emma; Doggett, Adrian; Bretnall, Alison

2014-08-05

Spray Dried Dispersions (SDD) are uniform mixtures of a specific ratio of amorphous active pharmaceutical ingredient (API) and polymer prepared via a spray drying process. Volatile solvents are employed during spray drying to facilitate the formation of the SDD material. Following manufacture, analytical methodology is required to determine residual levels of the spray drying solvent and its associated impurities. Due to the high level of polymer in the SDD samples, direct liquid injection with Gas Chromatography (GC) is not a viable option for analysis. This work describes the development and validation of an analytical approach to determine residual levels of acetone and acetone related impurities, mesityl oxide (MO) and diacetone alcohol (DAA), in drug product intermediates prepared as SDDs using GC with headspace (HS) autosampling. The method development for these analytes presented a number of analytical challenges which had to be overcome before the levels of the volatiles of interest could be accurately quantified. GCHS could be used after two critical factors were implemented; (1) calculation and application of conversion factors to 'correct' for the reactions occurring between acetone, MO and DAA during generation of the headspace volume for analysis, and the addition of an equivalent amount of polymer into all reference solutions used for quantitation to ensure comparability between the headspace volumes generated for both samples and external standards. This work describes the method development and optimisation of the standard preparation, the headspace autosampler operating parameters and the chromatographic conditions, together with a summary of the validation of the methodology. The approach has been demonstrated to be robust and suitable to accurately determine levels of acetone, MO and DAA in SDD materials over the linear concentration range 0.008-0.4μL/mL, with minimum quantitation limits of 20ppm for acetone and MO, and 80ppm for DAA. Copyright © 2014 Elsevier B.V. All rights reserved.

Standardization of spray-dried powder of Piper betle hot water extract

PubMed Central

Arawwawala, Liyanage Dona Ashanthi Menuka; Hewageegana, Horadugoda Gamage Sujatha Pushpakanthi; Arambewela, Lakshmi Sriyani Rajapaksha; Ariyawansa, Hettiarachchige Sami

2011-01-01

The leaves of Piper betle Linn. (Family: Piperaceae) possess several bioactivities and are used in the Traditional Medical systems of Sri Lanka. The present investigation was carried out to standardize the spray-dried powder of P. betle by (a) determination of physicochemical parameters, presence or absence of heavy metals, and microbial contamination; (b) screening for phytochemicals; and (c) development of High Pressure Liquid Chromatography (HPLC) fingerprint and densitogram. The percentages of moisture content, total ash, acid insoluble ash, water-soluble ash, and ethanol extractable matter of spray-dried powder of P. betle were 2.2-2.5, 6.8-7.0, 0.003-0.005, 4.1-4.3, and 15.8-16.2, respectively. The concentrations of all the tested heavy metals were below the WHO acceptable limits and bacterial species, such as Escherichia coli, Salmonella spp, Staphylococcus aureus, and Pseudomonas aeroginosa were not present in the P. betle spray-dried powder. Phenolic compounds, tannins, flavonoids steroids, and alkaloids were found to be present in the spray-dried powder of P. betle and HPLC fingerprint and densitogram clearly demonstrated the proportional differences of these chemical constituents. In conclusion, the results obtained from this study can be used to standardize the spray-dried powder of P. betle. PMID:21716924

Standardization of spray-dried powder of Piper betle hot water extract.

PubMed

Arawwawala, Liyanage Dona Ashanthi Menuka; Hewageegana, Horadugoda Gamage Sujatha Pushpakanthi; Arambewela, Lakshmi Sriyani Rajapaksha; Ariyawansa, Hettiarachchige Sami

2011-04-01

The leaves of Piper betle Linn. (Family: Piperaceae) possess several bioactivities and are used in the Traditional Medical systems of Sri Lanka. The present investigation was carried out to standardize the spray-dried powder of P. betle by (a) determination of physicochemical parameters, presence or absence of heavy metals, and microbial contamination; (b) screening for phytochemicals; and (c) development of High Pressure Liquid Chromatography (HPLC) fingerprint and densitogram. The percentages of moisture content, total ash, acid insoluble ash, water-soluble ash, and ethanol extractable matter of spray-dried powder of P. betle were 2.2-2.5, 6.8-7.0, 0.003-0.005, 4.1-4.3, and 15.8-16.2, respectively. The concentrations of all the tested heavy metals were below the WHO acceptable limits and bacterial species, such as Escherichia coli, Salmonella spp, Staphylococcus aureus, and Pseudomonas aeroginosa were not present in the P. betle spray-dried powder. Phenolic compounds, tannins, flavonoids steroids, and alkaloids were found to be present in the spray-dried powder of P. betle and HPLC fingerprint and densitogram clearly demonstrated the proportional differences of these chemical constituents. In conclusion, the results obtained from this study can be used to standardize the spray-dried powder of P. betle.

Acaricidal and repellent effects of Cnidium officinale-derived material against Dermanyssus gallinae (Acari: Dermanyssidae).

PubMed

Kim, Hyun Kyung; Lee, Seung Ju; Hwang, Bang-Yeon; Yoon, Jong Ung; Kim, Gil-Hah

2018-04-01

The acaricidal activity of a methanolic extract and fractions from the rhizome of Cnidium officinale against Dermanyssus gallinae adults was investigated. The C. officinale methanolic extract exhibited 100% acaricidal activity after 48 h of treatment at a dose of 4000 ppm. The acaricidal constituents of the plant were sequentially partitioned with several solvents and then purified using silica gel column chromatography and high-performance liquid chromatography. Gas chromatography-mass spectrometry and nuclear magnetic resonance spectroscopy revealed (Z)-ligustilide as a constituent of C. officinale. Acaricidal activity was examined in three experimental tests (spray, fumigation and contact), with the spraying method being the most effective. The methanolic extract of C. officinale showed both contact and fumigant activities, though only fumigant activity was observed with (Z)-ligustilide. The fumigant effects of the methanolic extract and (Z)-ligustilide caused 86.5 and 62.6% mortality, respectively, of D. gallinae adults at 48 h. Among (Z)-ligustilide, acaricides (bifenthrin, cypermethrin and spinosad) and butylidenephthalide, bifenthrin displayed the highest acaricidal activity, and the activity of butylidenephthalide was 2.3-fold higher than that of (Z)-ligustilide. These results suggest that C. officinale-derived material can be used for the development of a control agent for D. gallinae.

Design and Modelling of a Microfluidic Electro-Lysis Device with Controlling Plates

NASA Technical Reports Server (NTRS)

Jenkins, A.; Chen, C. P.; Spearing, S.; Monaco, L. A.; Steele, A.; Flores, G.

2006-01-01

Many Lab-on-Chip applications require sample pre-treatment systems. Using electric fields to perform cell-lysis in bio-MEMS systems has provided a powerful tool which can be integrated into Lab-on-a-Chip platforms. The major design considerations for electro-lysis devices include optimal geometry and placement of micro-electrodes, cell concentration, flow rates, optimal electric field (e.g. pulsed DC vs. AC), etc. To avoid electrolysis of the flowing solution at the exposed electrode surfaces, magnitudes and the applied voltages and duration of the DC pulse, or the AC frequency of the AC, have to be optimized for a given configuration. Using simulation tools for calculation of electric fields has proved very useful, for exploring alternative configurations and operating conditions for achieving electro cell-lysis. To alleviate the problem associated with low electric fields within the microfluidics channel and the high voltage demand on the contact electrode strips, two "control plates" are added to the microfluidics configuration. The principle of placing the two controlling plate-electrodes is based on the electric fields generated by a combined insulator/dielectric (gladwater) media. Surface charges are established at the insulator/dielectric interface. This paper discusses the effects of this interface charge on the modification of the electric field of the flowing liquid/cell solution.

Design and Modelling of a Microfluidic Electro-Lysis Device with Controlling Plates

NASA Astrophysics Data System (ADS)

Jenkins, A.; Chen, C. P.; Spearing, S.; Monaco, L. A.; Steele, A.; Flores, G.

2006-04-01

Many Lab-on-Chip applications require sample pre-treatment systems. Using electric fields to perform cell lysis in bio-MEMS systems has provided a powerful tool which can be integrated into Lab-on-a- Chip platforms. The major design considerations for electro-lysis devices include optimal geometry and placement of micro-electrodes, cell concentration, flow rates, optimal electric field (e.g. pulsed DC vs. AC), etc. To avoid electrolysis of the flowing solution at the exposed electrode surfaces, magnitudes and the applied voltages and duration of the DC pulse, or the AC frequency of the AC, have to be optimized for a given configuration. Using simulation tools for calculation of electric fields has proved very useful, for exploring alternative configurations and operating conditions for achieving electro cell-lysis. To alleviate the problem associated with low electric fields within the microfluidics channel and the high voltage demand on the contact electrode strips, two ''control plates'' are added to the microfluidics configuration. The principle of placing the two controlling plate-electrodes is based on the electric fields generated by a combined insulator/dielectric (glass/water) media. Surface charges are established at the insulator/dielectric interface. This paper discusses the effects of this interface charge on the modification of the electric field of the flowing liquid/cell solution.

Characterization of plasma sprayed and explosively consolidated simulated lunar soil

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

Powell, S.J.; Inal, O.T.; Smith, M.F.

1997-06-01

Two methods for the use of lunar materials for the construction of shelters on the Moon are being proposed: explosive consolidation of the soil into structural components and plasma spraying of the soil to join components. The plasma-sprayed coating would also provide protection from the intense radiation. In this work, a mare simulant was plasma-sprayed onto a stainless steel substrate. Deposition of a 0.020 inch coating using power inputs of 23, 25, 27 and 29 kW were compared. Hardness of the coatings increased with each increase of power to the system, while porosity at the interface decreased. All coatings exhibitedmore » good adhesion. Simultaneously, an explosively consolidated sample was similarly characterized to afford a comparison of structural features associated with each mode of proposed use.« less

Understanding the breakdown of classic two-phase theory and spray atomization at engine-relevant conditions

NASA Astrophysics Data System (ADS)

Dahms, Rainer N.

2016-04-01

A generalized framework for multi-component liquid injections is presented to understand and predict the breakdown of classic two-phase theory and spray atomization at engine-relevant conditions. The analysis focuses on the thermodynamic structure and the immiscibility state of representative gas-liquid interfaces. The most modern form of Helmholtz energy mixture state equation is utilized which exhibits a unique and physically consistent behavior over the entire two-phase regime of fluid densities. It is combined with generalized models for non-linear gradient theory and for liquid injections to quantify multi-component two-phase interface structures in global thermal equilibrium. Then, the Helmholtz free energy is minimized which determines the interfacial species distribution as a consequence. This minimal free energy state is demonstrated to validate the underlying assumptions of classic two-phase theory and spray atomization. However, under certain engine-relevant conditions for which corroborating experimental data are presented, this requirement for interfacial thermal equilibrium becomes unsustainable. A rigorously derived probability density function quantifies the ability of the interface to develop internal spatial temperature gradients in the presence of significant temperature differences between injected liquid and ambient gas. Then, the interface can no longer be viewed as an isolated system at minimal free energy. Instead, the interfacial dynamics become intimately connected to those of the separated homogeneous phases. Hence, the interface transitions toward a state in local equilibrium whereupon it becomes a dense-fluid mixing layer. A new conceptual view of a transitional liquid injection process emerges from a transition time scale analysis. Close to the nozzle exit, the two-phase interface still remains largely intact and more classic two-phase processes prevail as a consequence. Further downstream, however, the transition to dense-fluid mixing generally occurs before the liquid length is reached. The significance of the presented modeling expressions is established by a direct comparison to a reduced model, which utilizes widely applied approximations but fundamentally fails to capture the physical complexity discussed in this paper.

Comprehensive two-dimensional normal-phase liquid chromatography × reversed-phase liquid chromatography for analysis of toad skin.

PubMed

Li, Jia-Fu; Yan, Xia; Wu, Yun-Long; Fang, Mei-Juan; Wu, Zhen; Qiu, Ying-Kun

2017-04-15

An analytical two-dimensional normal-phase liquid chromatography × reversed-phase liquid chromatography (2D NPLC × RPLC) system was constructed with a newly developed thermal evaporation assisted adsorption (TEAA) interface. This novel TEAA interface with heating temperature above solvent boiling point allowed fast removal of organic NPLC solvent and successfully solved the solvent incompatibility problem between NPLC and RPLC. The system achieved rapid on-line solvent exchange between the two dimensions within a short modulation time of 190 s and was applied in the analysis of an extract from the skin of Bufo bufo gargarizans. This is the first time to realize the on-line comprehensive analysis of a moderate polar natural product by coupling NPLC with reversed phase ultra-high performance liquid chromatography (UHPLC). To be highlighted, with the TEAA interface, the 2D NPLC × RPLC system provided excellent resolution and orthogonality (75.2%), when compared with that of 2D RPLC × RPLC. Copyright © 2017 Elsevier B.V. All rights reserved.

A Comparison of Tissue Spray and Lipid Extract Direct Injection Electrospray Ionization Mass Spectrometry for the Differentiation of Eutopic and Ectopic Endometrial Tissues

NASA Astrophysics Data System (ADS)

Chagovets, Vitaliy; Wang, Zhihao; Kononikhin, Alexey; Starodubtseva, Natalia; Borisova, Anna; Salimova, Dinara; Popov, Igor; Kozachenko, Andrey; Chingin, Konstantin; Chen, Huanwen; Frankevich, Vladimir; Adamyan, Leila; Sukhikh, Gennady

2018-02-01

Recent research revealed that tissue spray mass spectrometry enables rapid molecular profiling of biological tissues, which is of great importance for the search of disease biomarkers as well as for online surgery control. However, the payback for the high speed of analysis in tissue spray analysis is the generally lower chemical sensitivity compared with the traditional approach based on the offline chemical extraction and electrospray ionization mass spectrometry detection. In this study, high resolution mass spectrometry analysis of endometrium tissues of different localizations obtained using direct tissue spray mass spectrometry in positive ion mode is compared with the results of electrospray ionization analysis of lipid extracts. Identified features in both cases belong to three lipid classes: phosphatidylcholines, phosphoethanolamines, and sphingomyelins. Lipids coverage is validated by hydrophilic interaction liquid chromatography with mass spectrometry of lipid extracts. Multivariate analysis of data from both methods reveals satisfactory differentiation of eutopic and ectopic endometrium tissues. Overall, our results indicate that the chemical information provided by tissue spray ionization is sufficient to allow differentiation of endometrial tissues by localization with similar reliability but higher speed than in the traditional approach relying on offline extraction.

Response surface optimization of electro-oxidation process for the treatment of C.I. Reactive Yellow 186 dye: reaction pathways

NASA Astrophysics Data System (ADS)

Rajkumar, K.; Muthukumar, M.

2017-05-01

In this study, central composite design at five levels (- β, -1, 0, +1, + β) combined with response surface methodology has been applied to optimize C.I. Reactive Yellow 186 using electro-oxidation process with graphite electrodes in a batch reactor. The variables considered were the pH ( X 1), NaCl concentration (M) ( X 2), and electrolysis time (min) ( X 3) on C.I. Reactive Yellow 186 were studied. A second-order empirical relationship between the response and independent variables was derived. Analysis of variance showed a high coefficient of determination value ( R 2 = 0.9556 and 0.9416 for color and COD, respectively). The optimized condition of the electro-oxidation of Reactive Yellow 186 is as follows: pH 3.9; NaCl concentration 0.11 M; and electrolysis time 18 min. Under this condition, the maximal decolorization efficiency of 99 % and COD removal 73 % was achieved. Detailed physico-chemical analysis of electrode and residues of the electro-oxidation process has also been carried out UV-Visible and Fourier transform infrared spectroscopy. The intermediate compounds formed during the oxidation were identified using a gas chromatography coupled with mass spectrometry. According to these results, response surface methodology could be useful for reducing the time to treat effluent wastewater.

Airborne Systems Course Textbook. Electro-Optical Systems Test and Evaluation,

DTIC Science & Technology

1981-06-01

by twice the angle between the reflecting faces. The porro - prism shown in Figure 2.2.3.1(c) is used to deflect the beam by 1800. Beam Retro-Reflection...Reflection of Electromagnetic Radiation at the Interface Between Two Media 2.13 2.2 Optics 2.15 2.2.1 The Lens 2.15 2.2.2 The Mirror 2.25 2.2.3 The Prism 2.30...2.5.2 The Optical Resonator 2.77 2.5.3 Laser Implementation 2.79 2.5.4 Laser Radiation Characteristics 2.81 2.6 Electro-Optical Sensors 2.83 2.6.1

Comparative Proteomic Analysis of Three Gelatinous Chinese Medicines and Their Authentications by Tryptic-digested Peptides Profiling using Matrix-assisted Laser Desorption/Ionization-time of Flight/Time of Flight Mass Spectrometry.

PubMed

Yang, Huan; Zheng, Jie; Wang, Hai-Yan; Li, Nan; Yang, Ya-Ya; Shen, Yu-Ping

2017-01-01

Gelatinous Chinese medicines (GCMs) including Asini Corii Colla, Testudinis Carapacis ET Plastri Colla, and Cervi Cornus Colla, were made from reptile shell or mammalian skin or deer horn, and consumed as a popular tonic, as well as hemopoietic and hemostatic agents. Misuse of them would not exert their functions, and fake or adulterate products have caused drug market disorder and affected food and drug safety. GCMs are rich in denatured proteins, but insufficient in available DNA fragments, hence commonly used cytochrome c oxidase I barcoding was not successful for their authentication. In this study, we performed comparative proteomic analysis of them and their animal origins to identify the composition of intrinsic proteins for the first time. A reliable and convenient approach was proposed for their authentication, by the incorporation of sodium dodecyl sulfate-polyacrylamide gel electrophoresis, two-dimensional electrophoresis, and matrix-assisted laser desorption/ionization-time of flight/time of flight mass spectrometry (MALDI-TOF/TOF-MS). A total of 26 proteins were identified from medicinal parts of original animals, and GCMs proteins presented in a dispersive manner in electrophoresis analyses due to complicated changes in the structure of original proteins caused by long-term decoction and the addition of ingredients during their manufacturing. In addition, by comparison of MALDI-TOF/TOF-MS profiling, 19 signature peptide fragments originated from the protein of GCM products were selected according to criteria. These could assist in the discrimination and identification of adulterates of GCMs and other ACMs for their form of raw medicinal material, the pulverized, and even the complex. Comparative proteomic analysis of three gelatinous Chinese medicines was conducted, and their authentications were based on tryptic-digested peptides profiling using matrix-assisted laser desorption/ionization-time of flight/time of flight mass spectrometry. Abbreviations used: GCMs: Gelatinous Chinese medicines, COI: Cytochrome c oxidase I, SDS-PAGE: Sodium dodecyl sulfate polyacrylamide gel electrophoresis, 2-DE: Two-dimensional electrophoresis, MALDI-TOF/TOF-MS: Matrix-assisted laser desorption/ionization-time of flight/time of flight mass spectrometry, LC: Liquid chromatography, ChP: Chinese Pharmacopoeia, HPLC: High performance liquid chromatography, LC-ESI + -MS: Liquid chromatography-electro spray ionization-mass spectrometry, IEF: isoelectric focusing, HCCA: α-Cyano-4-hydroxycinnamic acid.

A piezo-ring-on-chip microfluidic device for simple and low-cost mass spectrometry interfacing.

PubMed

Tsao, Chia-Wen; Lei, I-Chao; Chen, Pi-Yu; Yang, Yu-Liang

2018-02-12

Mass spectrometry (MS) interfacing technology provides the means for incorporating microfluidic processing with post MS analysis. In this study, we propose a simple piezo-ring-on-chip microfluidic device for the controlled spraying of MALDI-MS targets. This device uses a low-cost, commercially-available ring-shaped piezoelectric acoustic atomizer (piezo-ring) directly integrated into a polydimethylsiloxane microfluidic device to spray the sample onto the MS target substrate. The piezo-ring-on-chip microfluidic device's design, fabrication, and actuation, and its pulsatile pumping effects were evaluated. The spraying performance was examined by depositing organic matrix samples onto the MS target substrate by using both an automatic linear motion motor, and manual deposition. Matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) was performed to analyze the peptide samples on the MALDI target substrates. Using our technique, model peptides with 10 -6 M concentration can be successfully detected. The results also indicate that the piezo-ring-on-chip approach forms finer matrix crystals and presents better MS signal uniformity with little sample consumption compared to the conventional pipetting method.

Decontamination of Streptococci biofilms and Bacillus cereus spores on plastic surfaces with DC and pulsed corona discharges

NASA Astrophysics Data System (ADS)

Koval'ová, Zuzana; Tarabová, Kataŕna; Hensel, Karol; Machala, Zdenko

2013-02-01

Cold air plasmas of DC and pulsed corona discharges: positive streamers and negative Trichel pulses were used for bio-decontamination of Streptococci biofilm and Bacillus cereus spores on polypropylene plastic surfaces. The reduction of bacterial population (evaluated as log10) in the biofilm on plastic surfaces treated by DC corona reached 2.4 logs with 10 min treatment time and 3.3 logs with 2 min treatment time with water spraying. The enhancement of plasma biocidal effects on the biofilm by electro-spraying of water through a hollow needle high-voltage electrode was investigated. No significant polarity effect was found with DC corona. Pulsed corona was demonstrated slightly more bactericidal for spores, especially in the negative polarity where the bacterial population reduction reached up to 2.2 logs at 10 min exposure time. Contribution to the Topical Issue "13th International Symposium on High Pressure Low Temperature Plasma Chemistry (Hakone XIII)", Edited by Nicolas Gherardi, Henryca Danuta Stryczewska and Yvan Ségui.

Formation of structure, phase composition and properties of electro explosion resistant coatings using electron-beam processing

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

Romanov, Denis A., E-mail: romanov-da@physics.sibsiu.ru, E-mail: kos2906@mail.ru, E-mail: budovskih-ea@physics.sibsiu.ru, E-mail: gromov@physics.sibsiu.ru, E-mail: da-rom@live.ru; Sosnin, Kirill V., E-mail: romanov-da@physics.sibsiu.ru, E-mail: kos2906@mail.ru, E-mail: budovskih-ea@physics.sibsiu.ru, E-mail: gromov@physics.sibsiu.ru, E-mail: da-rom@live.ru; Budovskikh, Evgenij A., E-mail: romanov-da@physics.sibsiu.ru, E-mail: kos2906@mail.ru, E-mail: budovskih-ea@physics.sibsiu.ru, E-mail: gromov@physics.sibsiu.ru, E-mail: da-rom@live.ru

2014-11-14

For the first time, the high intensity electron beam modification of electroexplosion composite coatings of MoCu, MoCCu, WCu, WCCu and TiB{sub 2}Cu systems was done. The studies of phase and elemental composition, defective structure conditions of these coatings were carried out. The regimes of electron-beam processing making possible to form the dense, specular luster surface layers having a submicrocrystalline structure were revealed. It was established that electron-beam processing of elecroexplosion spraying of layer of elecroexplosion spraying carried out in the regime of melting results in the formation of structurally and contrationally homogeneous surface layer. Investigation of the effect of electron-beammore » processing of electroexplosion electroerosion resistant coatings on their tribological properties (wear resistanse and coefficient of friction) and electroerosion resistance was done. It was shown that all the examined costings demonstrate the increase of electroerosion resistance in spark erosion up to 10 times.« less

Voltage assisted asymmetric nanoscale wear on ultra-smooth diamond like carbon thin films at high sliding speeds

PubMed Central

Rajauria, Sukumar; Schreck, Erhard; Marchon, Bruno

2016-01-01

The understanding of tribo- and electro-chemical phenomenons on the molecular level at a sliding interface is a field of growing interest. Fundamental chemical and physical insights of sliding surfaces are crucial for understanding wear at an interface, particularly for nano or micro scale devices operating at high sliding speeds. A complete investigation of the electrochemical effects on high sliding speed interfaces requires a precise monitoring of both the associated wear and surface chemical reactions at the interface. Here, we demonstrate that head-disk interface inside a commercial magnetic storage hard disk drive provides a unique system for such studies. The results obtained shows that the voltage assisted electrochemical wear lead to asymmetric wear on either side of sliding interface. PMID:27150446

Voltage assisted asymmetric nanoscale wear on ultra-smooth diamond like carbon thin films at high sliding speeds

NASA Astrophysics Data System (ADS)

Rajauria, Sukumar; Schreck, Erhard; Marchon, Bruno

2016-05-01

The understanding of tribo- and electro-chemical phenomenons on the molecular level at a sliding interface is a field of growing interest. Fundamental chemical and physical insights of sliding surfaces are crucial for understanding wear at an interface, particularly for nano or micro scale devices operating at high sliding speeds. A complete investigation of the electrochemical effects on high sliding speed interfaces requires a precise monitoring of both the associated wear and surface chemical reactions at the interface. Here, we demonstrate that head-disk interface inside a commercial magnetic storage hard disk drive provides a unique system for such studies. The results obtained shows that the voltage assisted electrochemical wear lead to asymmetric wear on either side of sliding interface.

Cold Spray Coating of Submicronic Ceramic Particles on Poly(vinyl alcohol) in Dry and Hydrogel States

NASA Astrophysics Data System (ADS)

Moreau, David; Borit, François; Corté, Laurent; Guipont, Vincent

2017-06-01

We report an approach using cold spray technology to coat poly(vinyl alcohol) (PVA) in polymer and hydrogel states with hydroxyapatite (HA). Using porous aggregated HA powder, we hypothesized that fragmentation of the powder upon cold spray could lead to formation of a ceramic coating on the surface of the PVA substrate. However, direct spraying of this powder led to complete destruction of the swollen PVA hydrogel substrate. As an alternative, HA coatings were successfully produced by spraying onto dry PVA substrates prior to swelling in water. Dense homogeneous HA coatings composed of submicron particles were obtained using rather low-energy spraying parameters (temperature 200-250 °C, pressure 1-3 MPa). Coated PVA substrates could swell in water without removal of the ceramic layer to form HA-coated hydrogels. Microscopic observations and in situ measurements were used to explain how local heating and impact of sprayed aggregates induced surface roughening and strong binding of HA particles to the molten PVA substrate. Such an approach could lead to design of ceramic coatings whose roughness and crystallinity can be finely adjusted to improve interfacing with biological tissues.

Use of nitrogen to remove solvent from through oven transfer adsorption desorption interface during analysis of polycyclic aromatic hydrocarbons by large volume injection in gas chromatography.

PubMed

Áragón, Alvaro; Toledano, Rosa M; Cortés, José M; Vázquez, Ana M; Villén, Jesús

2014-04-25

The through oven transfer adsorption desorption (TOTAD) interface allows large volume injection (LVI) in gas chromatography and the on-line coupling of liquid chromatography and gas chromatography (LC-GC), enabling the LC step to be carried out in normal as well as in reversed phase. However, large amounts of helium, which is both expensive and scarce, are necessary for solvent elimination. We describe how slight modification of the interface and the operating mode allows nitrogen to be used during the solvent elimination steps. In order to evaluate the performance of the new system, volumes ranging from 20 to 100μL of methanolic solutions of four polycyclic aromatic hydrocarbons (PAHs) were sampled. No significant differences were found in the repeatability and sensitivity of the analyses of standard PAH solutions when using nitrogen or helium. The performance using the proposed modification was similar and equally satisfactory when using nitrogen or helium for solvent elimination in the TOTAD interface. In conclusion, the use of nitrogen will make analyses less expensive. Copyright © 2014 Elsevier B.V. All rights reserved.

First-Principles Study of the Band Diagrams and Schottky-Type Barrier Heights of Aqueous Ta3N5 Interfaces.

PubMed

Watanabe, Eriko; Ushiyama, Hiroshi; Yamashita, Koichi

2017-03-22

The photo(electro)chemical production of hydrogen by water splitting is an efficient and sustainable method for the utilization of solar energy. To improve photo(electro)catalytic activity, a Schottky-type barrier is typically useful to separate excited charge carriers in semiconductor electrodes. Here, we focused on studying the band diagrams and the Schottky-type barrier heights of Ta 3 N 5 , which is one of the most promising materials as a photoanode for water splitting. The band alignments of the undoped and n-type Ta 3 N 5 with adsorbents in a vacuum were examined to determine how impurities and adsorbents affect the band positions and Fermi energies. The band edge positions as well as the density of surface states clearly depended on the density of O N impurities in the bulk and surface regions. Finally, the band diagrams of the n-type Ta 3 N 5 /water interfaces were calculated with an improved interfacial model to include the effect of electrode potential with explicit water molecules. We observed partial Fermi level pinning in our calculations at the Ta 3 N 5 /water interface, which affects the driving force for charge separation.

Active Surfaces and Interfaces of Soft Materials

NASA Astrophysics Data System (ADS)

Wang, Qiming

A variety of intriguing surface patterns have been observed on developing natural systems, ranging from corrugated surface of white blood cells at nanometer scales to wrinkled dog skins at millimeter scales. To mimetically harness functionalities of natural morphologies, artificial transformative skin systems by using soft active materials have been rationally designed to generate versatile patterns for a variety of engineering applications. The study of the mechanics and design of these dynamic surface patterns on soft active materials are both physically interesting and technologically important. This dissertation starts with studying abundant surface patterns in Nature by constructing a unified phase diagram of surface instabilities on soft materials with minimum numbers of physical parameters. Guided by this integrated phase diagram, an electroactive system is designed to investigate a variety of electrically-induced surface instabilities of elastomers, including electro-creasing, electro-cratering, electro-wrinkling and electro-cavitation. Combing experimental, theoretical and computational methods, the initiation, evolution and transition of these instabilities are analyzed. To apply these dynamic surface instabilities to serving engineering and biology, new techniques of Dynamic Electrostatic Lithography and electroactive anti-biofouling are demonstrated.

Interface characterization of Cu-Mo coating deposited on Ti-Al alloys by arc spraying

NASA Astrophysics Data System (ADS)

Bai, Shengqiang; Li, Fei; Wu, Ting; Yin, Xianglin; Shi, Xun; Chen, Lidong

2015-03-01

Cu-Mo pseudobinary alloys are promising candidates as electrode materials in CoSb3-based skutterudite thermoelectric (TE) devices for TE power generation. In this study, Cu-Mo coatings were deposited onto Ti-Al substrates by applying a dual-wire electric arc spraying coating technique. The microstructure of the surfaces, cross sections and coating interfaces were analyzed by scanning electron microscopy (SEM) and energy dispersion spectrometry (EDS). Cu-Mo coatings showed a typical banded splat with compact microstructures, and have no coarse pores nor micro-cracks. The thermal shock resistance of the Cu-Mo coating was also investigated to show good combinations with Ti-Al substrates. After 50 thermal shock cycles, there were no cracks observed at the interface. In contrast, the test of the thermal shock resistance of the Cu coating on the Ti-Al substrate was also investigated. Due to a large difference in the thermal expansion coefficients between Cu and Ti-Al alloys, the Cu coating flaked from the Ti-Al substrate completely after 10 thermal shock cycles. The contact resistivity of the Ti-Al/Cu-Mo interface was about 1.6 μΩṡcm2 and this value was unchanged after 50 thermal shock cycles, indicating the low electric resistance and high thermal stability of the Cu-Mo/Ti-Al interface.

A phase I study to assess the single and multiple dose pharmacokinetics of THC/CBD oromucosal spray.

PubMed

Stott, C G; White, L; Wright, S; Wilbraham, D; Guy, G W

2013-05-01

A Phase I study to assess the single and multipledose pharmacokinetics (PKs) and safety and tolerability of oromucosally administered Δ(9)-tetrahydrocannabinol (THC)/cannabidiol (CBD) spray, an endocannabinoid system modulator, in healthy male subjects. Subjects received either single doses of THC/CBD spray as multiple sprays [2 (5.4 mg THC and 5.0 mg CBD), 4 (10.8 mg THC and 10.0 mg CBD) or 8 (21.6 mg THC and 20.0 mg CBD) daily sprays] or multiple doses of THC/CBD spray (2, 4 or 8 sprays once daily) for nine consecutive days, following fasting for a minimum of 10 h overnight prior to each dosing. Plasma samples were analyzed by gas chromatography-mass spectrometry for CBD, THC, and its primary metabolite 11-hydroxy-THC, and various PK parameters were investigated. Δ(9)-Tetrahydrocannabinol and CBD were rapidly absorbed following single-dose administration. With increasing single and multiple doses of THC/CBD spray, the mean peak plasma concentration (Cmax) increased for all analytes. There was evidence of dose-proportionality in the single but not the multiple dosing data sets. The bioavailability of THC was greater than CBD at single and multiple doses, and there was no evidence of accumulation for any analyte with multiple dosing. Inter-subject variability ranged from moderate to high for all PK parameters in this study. The time to peak plasma concentration (Tmax) was longest for all analytes in the eight spray group, but was similar in the two and four spray groups. THC/CBD spray was well-tolerated in this study and no serious adverse events were reported. The mean Cmax values (<12 ng/mL) recorded in this study were well below those reported in patients who smoked/inhaled cannabis, which is reassuring since elevated Cmax values are linked to significant psychoactivity. There was also no evidence of accumulation on repeated dosing.

Azinphos-methyl residues in apples and spatial distribution of fluorescein in vase-shaped apple trees.

PubMed

Bélanger, A; Bostanian, N J; Boivin, G; Boudreau, F

1991-06-01

Vase-shaped standard apple trees cv. McIntosh were sprayed with azinphos-methyl at pink, pink and 1st cover and 1st cover only. Residue analyses by gas chromatography revealed detectable residues on foliage until mid summer. At harvest, negligible residue levels were found on the peel and the whole apple. On four trees, fluorescein was sprayed in the same manner as the insecticide and maximum levels of the dye were detected on the outside lower canopy along the row. Minimal concentration of fluorescein was detected on the inner upper canopy away from the direction of the row.

Comparative characteristic and erosion behavior of NiCr coatings deposited by various high-velocity oxyfuel spray processes

NASA Astrophysics Data System (ADS)

Sidhu, Hazoor Singh; Sidhu, Buta Singh; Prakash, S.

2006-12-01

The purpose of this study is to analyze and compare the mechanical properties and microstructure details at the interface of high-velocity oxyfuel (HVOF)-sprayed NiCr-coated boiler tube steels, namely ASTM-SA-210 grade A1, ASTM-SA213-T-11, and ASTM-SA213-T-22. Coatings were developed by two different techniques, and in these techniques liquefied petroleum gas was used as the fuel gas. First, the coatings were characterized by metallographic, scanning electron microscopy/energy-dispersive x-ray analysis, x-ray diffraction, surface roughness, and microhardness, and then were subjected to erosion testing. An attempt has been made to describe the transformations taking place during thermal spraying. It is concluded that the HVOF wire spraying process offers a technically viable and cost-effective alternative to HVOF powder spraying process for applications in an energy generation power plant with a point view of life enhancement and to minimize the tube failures because it gives a coating having better resistance to erosion.

A sputtered zirconia primer for improved thermal shock resistance of plasma sprayed ceramic turbine seals

NASA Technical Reports Server (NTRS)

Bill, R. C.; Sovey, J.; Allen, G. P.

1981-01-01

The development of plasma-sprayed yttria stabilized zirconia (YSZ) ceramic turbine blade tip seal components is discussed. The YSZ layers are quite thick (0.040 to 0.090 in.). The service potential of seal components with such thick ceramic layers is cyclic thermal shock limited. The most usual failure mode is ceramic layer delamination at or very near the interface between the plasma sprayed YSZ layer and the NiCrAlY bondcoat. Deposition of a thin RF sputtered YSZ primer to the bondcoat prior to deposition of the thick plasma sprayed YSZ layer was found to reduce laminar cracking in cyclic thermal shock testing. The cyclic thermal shock life of one ceramic seal design was increased by a factor of 5 to 6 when the sputtered YSZ primer was incorporated. A model based on thermal response of plasma sprayed YSZ particles impinging on the bondcoat surface with and without the sputtered YSZ primer provides a basis for understanding the function of the primer.

Degradation of thiamethoxam by the synergetic effect between anodic oxidation and Fenton reactions.

PubMed

Meijide, J; Gómez, J; Pazos, M; Sanromán, M A

2016-12-05

In this work, a comparative study using anodic oxidation, Fenton and electro-Fenton treatments was performed in order to determine the synergic effect for the removal of thiamethoxan. The results determined that electro-Fenton process showed high efficiency in comparison with Fenton or anodic oxidation. After that, this hybrid process was optimized and the influence of iron catalyst concentration and applied current intensity on the degradation and mineralization were evaluated. Degradation profiles were monitored by high performance liquid chromatography (HPLC) being satisfactorily described by pseudo-first order kinetic model. At the optimal experimental conditions (300mA and 0.2mM Fe(+2)), the complete degradation of thiamethoxam was achieved after 10min. On the other hand, mineralization of thiamethoxam was monitored by total organic carbon (TOC) decay reaching more than 92% of TOC removal after 8h. Furthermore, a plausible mineralization pathway for the thiamethoxam degradation was proposed based on the identification of by-products such as aromatic intermediates, carboxylic acids and inorganic ions released throughout electro-Fenton process. Copyright © 2016 Elsevier B.V. All rights reserved.

Influence of Impact Conditions on Feedstock Deposition Behavior of Cold-Sprayed Fe-Based Metallic Glass

NASA Astrophysics Data System (ADS)

Ziemian, Constance W.; Wright, Wendelin J.; Cipoletti, David E.

2018-05-01

Cold spray is a promising method by which to deposit dense Fe-based metallic glass coatings on conventional metal substrates. Relatively low process temperatures offer the potential to prevent the crystallization of amorphous feedstock powders while still providing adequate particle softening for bonding and coating formation. In this study, Fe48Mo14Cr15Y2C15B6 powder was sprayed onto a mild steel substrate, using a variety of process conditions, to investigate the feasibility of forming well-bonded amorphous Fe-based coatings. Particle splat adhesion was examined relative to impact conditions, and the limiting values of temperature and velocity associated with successful softening and adhesion were empirically established. Variability of particle sizes, impact temperatures, and impact velocities resulted in splat morphologies ranging from well-adhered deformed particles to substrate craters formed by rebounded particles and a variety of particle/substrate interface conditions. Transmission electron microscopy studies revealed the presence of a thin oxide layer between well-adhered particles and the substrate, suggesting that bonding is feasible even with an increased oxygen content at the interface. Results indicate that the proper optimization of cold spray process parameters supports the formation of Fe-based metallic glass coatings that successfully retain their amorphous structure, as well as the superior corrosion and wear-resistant properties of the feedstock powder.

Method for Continuous Monitoring of Electrospray Ion Formation

NASA Astrophysics Data System (ADS)

Metzler, Guille; Crathern, Susan; Bachmann, Lorin; Fernández-Metzler, Carmen; King, Richard

2017-10-01

A method for continuously monitoring the performance of electrospray ionization without the addition of hardware or chemistry to the system is demonstrated. In the method, which we refer to as SprayDx, cluster ions with solvent vapor natively formed by electrospray are followed throughout the collection of liquid chromatography-selected reaction monitoring data. The cluster ion extracted ion chromatograms report on the consistency of the ion formation and detection system. The data collected by the SprayDx method resemble the data collected for postcolumn infusion of analyte. The response of the cluster ions monitored reports on changes in the physical parameters of the ion source such as voltage and gas flow. SprayDx is also observed to report on ion suppression in a fashion very similar to a postcolumn infusion of analyte. We anticipate the method finding utility as a continuous readout on the performance of electrospray and other atmospheric pressure ionization processes. [Figure not available: see fulltext.

Combinatorial electrochemical synthesis and screening of Pt-WO3 catalysts for electro-oxidation of methanol

NASA Astrophysics Data System (ADS)

Jayaraman, Shrisudersan; Baeck, Sung-Hyeon; Jaramillo, Thomas F.; Kleiman-Shwarsctein, Alan; McFarland, Eric W.

2005-06-01

An automated system for high-throughput electrochemical synthesis and screening of fuel cell electro-oxidation catalysts is described. This system consists of an electrode probe that contains counter and reference electrodes that can be positioned inside an array of electrochemical cells created within a polypropylene block. The electrode probe is attached to an automated of X-Y-Z motion system. An externally controlled potentiostat is used to apply the electrochemical potential to the catalyst substrate. The motion and electrochemical control are integrated using a user-friendly software interface. During automated synthesis the deposition potential and/or current may be controlled by a pulse program triggered by the software using a data acquisition board. The screening includes automated experiments to obtain cyclic voltammograms. As an example, a platinum-tungsten oxide (Pt-WO3) library was synthesized and characterized for reactivity towards methanol electro-oxidation.

Sudden death involving inhalation of 1,1-difluoroethane (HFC-152a) with spray cleaner: three case reports.

PubMed

Sakai, Kentaro; Maruyama-Maebashi, Kyoko; Takatsu, Akihiro; Fukui, Kenji; Nagai, Tomonori; Aoyagi, Miwako; Ochiai, Eriko; Iwadate, Kimiharu

2011-03-20

Spray cleaner is a cleaning product containing compressed 1,1-difluoroethane (HFC-152a) to blow dust off electric devices and other sensitive equipment; however, it is also inhaled to induce euphoria. This report describes three cases of death involving HFC-152a inhalation with spray cleaner under different circumstances. In case 1, death was during inhalation for euphoria with which led to having frostbite. In case 2, death may have been associated with suicidal intention. Case 3 was also considered an accidental autoerotic death. In all three cases, HFC-152a was detected at 99.2-136.2mg/l in blood samples, 94.5-191.9 mg/l in urine samples and 3.6-18.4 mg in the gastric contents according to gas chromatography with flame ionization detection. To prevent death associated with HFC-152a inhalation from spray cleaner, the danger of the sudden death should be announced to people, given the ready availability of commercial products containing HFC-152a. Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.

DEFENSIVE SPIROKETALS FROM Asceles glaber (PHASMATODEA): ABSOLUTE CONFIGURATION AND EFFECTS ON ANTS AND MOSQUITOES

PubMed Central

DOSSEY, AARON T.; WHITAKER, JOHN M.; DANCEL, MARIA CRISTINA A.; VANDER MEER, ROBERT K.; BERNIER, ULRICH R.; GOTTARDO, MARCO; ROUSH, WILLIAM R.

2012-01-01

Insects are the largest and most diverse group of organisms on earth, with over 1,000,000 species identified to date. Stick insects (“walkingsticks” or “phasmids”, Order Phasmatodea) are well known for and name derived from their uncanny stereotypical use of camouflage as a primary line of defense from predation. However, many species also possess a potent chemical defense spray. Recently we discovered that the defensive spray of Asceles glaber contains spiroketals (confirmed major component: (2S,6R)-(−)(E)-2-methyl-1,7-dioxaspiro[5.5]undecane and tentative minor component: 2-ethyl-1,6-dioxaspiro[4.5]decane) and glucose. In this paper we 1) illustrate the identification of spiroketals and glucose in the defense spray of A. glaber using Nuclear Magnetic Resonance (NMR), Gas Chromatography/Mass Spectrometry (GC/MS), and comparison with a synthetic reference sample, 2) provide the elucidation of the absolute configuration of the major spiroketal in that defense spray and 3) demonstrate the effect of this compound and its enantiomer on both fire ants (Solenopsis invicta) and mosquitoes (Aedes aegypti). PMID:22976590

Use of absorbent materials in on-line coupled reversed-phase liquid chromatography-gas chromatography via the through oven transfer adsorption desorption interface.

PubMed

Flores, Gema; Díaz-Plaza, Eva María; Cortés, Jose Manuel; Villén, Jesús; Herraiz, Marta

2008-11-21

The use of absorbents as retaining materials in the through oven transfer adsorption desorption interface (TOTAD) of an on-line coupled reversed-phase liquid chromatography-gas chromatography system (RPLC-GC) is proposed for the first time. A comparative study of an adsorbent (Tenax TA) and two absorbents, namely polydimethylsiloxane and poly(50% phenyl/50% methylsiloxane) is performed to establish the best experimental conditions for the automated and simultaneous determination of 15 organophosphorus and organochlorine pesticide residues in olive oil. The proposed method provides satisfactory repeatability (RSDs lower, in general, than 8.5%) and sensitivity (limits of detection ranging from 0.6 to 81.9 microg/L) for the investigated compounds.

Interfacial electrofluidics in confined systems

PubMed Central

Tang, Biao; Groenewold, Jan; Zhou, Min; Hayes, Robert A.; Zhou, Guofu (G.F.)

2016-01-01

Electrofluidics is a versatile principle that can be used for high speed actuation of liquid interfaces. In most of the applications, the fundamental mechanism of electro-capillary instability plays a crucial role, yet it’s potential richness in confined fluidic layers has not been well addressed. Electrofluidic displays which are comprised of thin pixelated colored films in a range of architectures are excellent systems for studying such phenomena. In this study we show theoretically and experimentally that confinement leads to the generation of a cascade of voltage dependent modes as a result of the electro-capillary instability. In the course of reconciling theory with our experimental data we have observed a number of previously unreported phenomena such as a significant induction time (several milliseconds) prior to film rupture as well as a rupture location not corresponding to the minimum electric field strength in the case of the standard convex water/oil interface used in working devices. These findings are broadly applicable to a wide range of switchable electrofluidic applications and devices having confined liquid films. PMID:27221211

CHLORIDEDETERMINATION IN HIGH IONIC STRENGTH SOLUTION OF AMMONIUM ACETATE USING NEGATIVE ION ELECTRON SPRAY IONIZATION (HPLC/MS)

EPA Science Inventory

A precise ion chromatography method has been developed for the determination of chloride in high ionic strength ammonium acetate solutions (10-5 M-5 M) using sodium carbonate/sodium bicarbonate as eluent. Negative ion electrospray ionization (ESI) mass spectrometry was used for q...

Analysis of biodiesel and biodiesel-petrodiesel blends by high performance thin layer chromatography combined with easy ambient sonic-spray ionization mass spectrometry.

PubMed

Eberlin, Livia S; Abdelnur, Patricia V; Passero, Alan; de Sa, Gilberto F; Daroda, Romeu J; de Souza, Vanderlea; Eberlin, Marcos N

2009-08-01

High performance thin layer chromatography (HPTLC) combined with on-spot detection and characterization via easy ambient sonic-spray ionization mass spectrometry (EASI-MS) is applied to the analysis of biodiesel (B100) and biodiesel-petrodiesel blends (BX). HPTLC provides chromatographic resolution of major components whereas EASI-MS allows on-spot characterization performed directly on the HPTLC surface at ambient conditions. Constituents (M) are detected by EASI-MS in a one component-one ion fashion as either [M + Na](+) or [M + H](+). For both B100 and BX samples, typical profiles of fatty acid methyl esters (FAME) detected as [FAME + Na](+) ions allow biodiesel typification. The spectrum of the petrodiesel spot displays a homologous series of protonated alkyl pyridines which are characteristic for petrofuels (natural markers). The spectrum for residual or admixture oil spots is characterized by sodiated triglycerides [TAG + Na](+). The application of HPTLC to analyze B100 and BX samples and its combination with EASI-MS for on-spot characterization and quality control is demonstrated.

LSD and 9,10-dihydro-LSD analyses in street drug blotter samples via easy ambient sonic-spray ionization mass spectrometry (EASI-MS).

PubMed

Romão, Wanderson; Sabino, Bruno D; Bueno, Maria Izabel M S; Vaz, Boniek G; Júnior, Amadeu C; Maldaner, Adriano O; de Castro, Eustáquio V R; Lordeiro, Rogério A; Nascentes, Clésia C; Eberlin, Marcos N; Augusti, Rodinei

2012-09-01

Normally, the identification of the LSD drug is performed by forensic laboratories, using the Ehrlich spot test. However, this is a nonspecific analysis. Additionally, the Brazilian Federal Police has identified the presence of a new compound in seized blotters: 9,10-dihydro-LSD, an uncontrolled substance. In this work, easy ambient sonic-spray ionization mass spectrometry in the positive ion mode, EASI(+)-MS, was used to characterize LSD and 9,10-dihydro-LSD compositions directly from the surface of blotters. The presence of LSD in the seized blotter samples were also confirmed via high-performance liquid chromatography with ultraviolet detector. In a set of 41 blotters analyzed by EASI(+)-MS, 28 showed positive results for LSD, seven for 9,10-dihydro-LSD, and another six samples showed negative results for both LSD and 9,10-dihydro-LSD. The combination of thin layer chromatography with EASI-MS also demonstrated to be a relatively simple and powerful screening tool for forensic analysis of street drugs. © 2012 American Academy of Forensic Sciences.

A case of homicidal intoxication by chloropicrin.

PubMed

Gonmori, K; Muto, H; Yamamoto, T; Takahashi, K

1987-06-01

An 18-year-old girl and her boyfriend were sprayed with toxic chemicals from the left front door of their parked car. The girl died of intoxication about 4 h later. The main findings of postmortem examination were spotty discolorations on her skin and severe pulmonary edema. The unknown chemical was identified as chloropicrin by gas-liquid chromatography and gas chromatography-mass spectrometry of her lung and on samples from the car's console box, cassette tape case, and floor mat, all of which were wet with chemicals. The content of chloropicrin in her lung was calculated at 1.6 ng/g of wet weight.

The potential role of sea spray droplets in facilitating air-sea gas transfer

NASA Astrophysics Data System (ADS)

Andreas, E. L.; Vlahos, P.; Monahan, E. C.

2016-05-01

For over 30 years, air-sea interaction specialists have been evaluating and parameterizing the role of whitecap bubbles in air-sea gas exchange. To our knowledge, no one, however, has studied the mirror image process of whether sea spray droplets can facilitate air-sea gas exchange. We are therefore using theory, data analysis, and numerical modeling to quantify the role of spray on air-sea gas transfer. In this, our first formal work on this subject, we seek the rate-limiting step in spray-mediated gas transfer by evaluating the three time scales that govern the exchange: τ air , which quantifies the rate of transfer between the atmospheric gas reservoir and the surface of the droplet; τ int , which quantifies the exchange rate across the air-droplet interface; and τ aq , which quantifies gas mixing within the aqueous solution droplet.

High heat flux properties of pure tungsten and plasma sprayed tungsten coatings

NASA Astrophysics Data System (ADS)

Liu, X.; Tamura, S.; Tokunaga, K.; Yoshida, N.; Noda, N.; Yang, L.; Xu, Z.

2004-08-01

High heat flux properties of pure tungsten and plasma sprayed tungsten coatings on carbon substrates have been studied by annealing and cyclic heat loading. The recrystallization temperature and an activation energy QR=126 kJ/mol for grain growth of tungsten coating by vacuum plasma spray (VPS) were estimated, and the microstructural changes of multi-layer tungsten and rhenium interface pre-deposited by physical vapor deposition (PVD) with anneal temperature were investigated. Cyclic load tests indicated that pure tungsten and VPS-tungsten coating could withstand 1000 cycles at 33-35 MW/m 2 heat flux and 3 s pulse duration, and inert gas plasma spray (IPS)-tungsten coating showed local cracks by 300 cycles but did not induce failure by further cycles. However, the failure of pure tungsten and VPS-tungsten coating by fatigue cracking was observed under higher heat load (55-60 MW/m 2) for 420 and 230 cycles, respectively.

Development of Detonation Flame Sprayed Cu-Base Coatings Containing Large Ceramic Particles

NASA Astrophysics Data System (ADS)

Tillmann, Wolfgang; Vogli, Evelina; Nebel, Jan

2007-12-01

Metal-matrix composites (MMCs) containing large ceramic particles as superabrasives are typically used for grinding stone, minerals, and concrete. Sintering and brazing are the key manufacturing technologies for grinding tool production. However, restricted geometry flexibility and the absence of repair possibilities for damaged tool surfaces, as well as difficulties of controlling material interfaces, are the main weaknesses of these production processes. Thermal spraying offers the possibility to avoid these restrictions. The research for this paper investigated a fabrication method based on the use of detonation flame spraying technology to bond large superabrasive particles (150-600 μm, needed for grinding minerals and stones) in a metallic matrix. Layer morphology and bonding quality are evaluated with respect to superabrasive material, geometry, spraying, and powder-injection parameters. The influence of process temperature and the possibilities of thermal treatment of MMC layers are analyzed.

Crack Initiation and Growth Behavior of Cold-Sprayed Ni Particles on IN718 Alloy

NASA Astrophysics Data System (ADS)

Cavaliere, P.; Silvello, A.

2017-04-01

Cold spray processing parameters, governing particle velocity and impact energy, are analyzed in the present paper for pure Ni sprayed on IN718 substrates. Finite element modeling (FEM) was used to calculate the particle impact velocity and temperature as a function of gas temperature and pressure and particle density and dimensions. Experimental evidence underlines the possibility of performing repairing through cold spray thanks to the good level of adhesion achievable by employing optimal combinations of materials and spray processing parameters. In the present paper, the potential repairing of cracked superalloys sheets, by employing cold spray technology, is presented. 30° surface V-notched IN718 panels have been repaired by using pure Ni cold-sprayed powders. The bending behavior of the repaired sheets was analyzed by FEM and mechanical testing in order to compare the properties with those belonging to the unrepaired panels. Simulations and mechanical results showed a reduction in the stress intensity factor, a modification of the crack initiation site and a crack retardation in the repaired structures if compared with the unrepaired ones. The K factor was quantified; the resistance of repaired panels was increased of more than eight times in the case of repairing with Ni cold spray particles. Geometrical and mechanical properties of the coating-substrate interfaces, such as adhesion strength and residual stresses influencing the coatings behavior, were largely analyzed.

Effect of layer thickness on the properties of nickel thermal sprayed steel

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

Nurisna, Zuhri, E-mail: zuhri-nurisna@yahoo.co.id; Triyono,, E-mail: triyonomesin@uns.ac.id; Muhayat, Nurul, E-mail: nurulmuhayat@staff.uns.ac.id

Thermal arc spray nickel coating is widely used for decorative and functional applications, by improving corrosion resistance, wear resistance, heat resistence or by modifying other properties of the coated materials. There are several properties have been studied. Layer thickness of nickel thermal sprayed steel may be make harder the substrate surface. In this study, the effect of layer thickness of nickel thermal sprayed steel has been investigated. The rectangular substrate specimens were coated by Ni–5 wt.% Al using wire arc spray method. The thickness of coating layers were in range from 0.4 to 1.0 mm. Different thickness of coating layers weremore » conducted to investigate their effect on hardness and morphology. The coating layer was examined by using microvickers and scanning electron microscope with EDX attachment. Generally, the hardness at the interface increased with increasing thickness of coating layers for all specimens due to higher heat input during spraying process. Morphology analysis result that during spraying process aluminum would react with surrounding oxygen and form aluminum oxide at outer surface of splat. Moreover, porosity was formed in coating layers. However, presence porosity is not related to thickness of coating material. The thicker coating layer resulted highesr of hardness and bond strength.« less

Effects of MgO and SiO2 on Plasma-Sprayed Hydroxyapatite Coating: An in Vivo Study in Rat Distal Femoral Defects.

PubMed

Ke, Dongxu; Robertson, Samuel F; Dernell, William S; Bandyopadhyay, Amit; Bose, Susmita

2017-08-09

Plasma-sprayed hydroxyapatite (HA)-coated titanium implants have been widely used in orthopedic applications due to their inheritance of an excellent mechanical property from titanium and great osteoconductivity from HA. However, the lack of osteoinductivity limits their further applications. In this study, 1 wt % MgO and 0.5 wt % SiO 2 were mixed with HA for making plasma-sprayed coatings on titanium implants. Plasma-sprayed HA- and MgO/SiO 2 -HA-coated titanium implants showed adhesive bond strengths of 25.73 ± 1.92 and 23.44 ± 2.89 MPa, respectively. The presence of MgO and SiO 2 significantly increased the osteogenesis, osseointegration, and bone mineralization of HA-coated titanium implants by the evaluation of their histomorphology after 6, 10, and 14 weeks of implantation in rat distal femoral defects. Implant pushout tests also showed a shear modulus of 149.83 ± 3.69 MPa for MgO/SiO 2 -HA-coated implants after 14 weeks of implantation, compared to 52.68 ± 10.41 MPa for uncoated implants and 83.92 ± 3.68 MPa for pure HA-coated implants; These are differences in the shear modulus of 96% and 56.4%, respectively. This study assesses for the first time the quality of the bone-implant interface of induction plasma-sprayed MgO and SiO 2 binary-doped HA coatings on load-bearing implants compared to bare titanium and pure HA coatings in a quantitative manner. Relating the osseointegration and interface shear modulus to the quality of implant fixation is critical to the advancement and implementation of HA-coated orthopedic implants.

Lubricating system for thermal medium delivery parts in a gas turbine

DOEpatents

Mashey, Thomas Charles

2002-01-01

Cooling steam delivery tubes extend axially along the outer rim of a gas turbine rotor for supplying cooling steam to and returning spent cooling steam from the turbine buckets. Because of the high friction forces at the interface of the tubes and supporting elements due to rotor rotation, a low coefficient of friction coating is provided at the interface of the tubes and support elements. On each surface, a first coating of a cobalt-based alloy is sprayed onto the surface at high temperature. A portion of the first coating is machined off to provide a smooth, hard surface. A second ceramic-based solid film lubricant is sprayed onto the first coating. By reducing the resistance to axial displacement of the tubes relative to the supporting elements due to thermal expansion, the service life of the tubes is substantially extended.

Conversion of iodide to hypoiodous acid and iodine in aqueous microdroplets exposed to ozone.

PubMed

Pillar, Elizabeth A; Guzman, Marcelo I; Rodriguez, Jose M

2013-10-01

Halides are incorporated into aerosol sea spray, where they start the catalytic destruction of ozone (O3) over the oceans and affect the global troposphere. Two intriguing environmental problems undergoing continuous research are (1) to understand how reactive gas phase molecular halogens are directly produced from inorganic halides exposed to O3 and (2) to constrain the environmental factors that control this interfacial process. This paper presents a laboratory study of the reaction of O3 at variable iodide (I(-)) concentration (0.010-100 μM) for solutions aerosolized at 25 °C, which reveal remarkable differences in the reaction intermediates and products expected in sea spray for low tropospheric [O3]. The ultrafast oxidation of I(-) by O3 at the air-water interface of microdroplets is evidenced by the appearance of hypoiodous acid (HIO), iodite (IO2(-)), iodate (IO3(-)), triiodide (I3(-)), and molecular iodine (I2). Mass spectrometry measurements reveal an enhancement (up to 28%) in the dissolution of gaseous O3 at the gas-liquid interface when increasing the concentration of NaI or NaBr from 0.010 to 100 μM. The production of iodine species such as HIO and I2 from NaI aerosolized solutions exposed to 50 ppbv O3 can occur at the air-water interface of sea spray, followed by their transfer to the gas-phase, where they contribute to the loss of tropospheric ozone.

Helium microwave-induced plasmas for element specific detection in chromatography

NASA Astrophysics Data System (ADS)

Long, Gary L.; Ducatte, Gerald R.; Lancaster, Edwin D.

1994-01-01

This review addresses the development and use of the microwave-induced plasma (MIP) using optical emission spectrometry for the purpose of element specific detection in chromatography. The plasma source that is the focus of this article is the He-based MIP operated at atmospheric pressure. The forms of chromatography that are covered include gas chromatography, liquid chromatography, and supercritical fluid chromatography. Concepts in plasma cavity design and the chromatograph-plasma interface are discussed along with the application of these hybrid systems to analytical determinations.

Understanding the breakdown of classic two-phase theory and spray atomization at engine-relevant conditions

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

Dahms, Rainer N.

A generalized framework for multi-component liquid injections is presented to understand and predict the breakdown of classic two-phase theory and spray atomization at engine-relevant conditions. The analysis focuses on the thermodynamic structure and the immiscibility state of representative gas-liquid interfaces. The most modern form of Helmholtz energy mixture state equation is utilized which exhibits a unique and physically consistent behavior over the entire two-phase regime of fluid densities. It is combined with generalized models for non-linear gradient theory and for liquid injections to quantify multi-component two-phase interface structures in global thermal equilibrium. Then, the Helmholtz free energy is minimized whichmore » determines the interfacial species distribution as a consequence. This minimal free energy state is demonstrated to validate the underlying assumptions of classic two-phase theory and spray atomization. However, under certain engine-relevant conditions for which corroborating experimental data are presented, this requirement for interfacial thermal equilibrium becomes unsustainable. A rigorously derived probability density function quantifies the ability of the interface to develop internal spatial temperature gradients in the presence of significant temperature differences between injected liquid and ambient gas. Then, the interface can no longer be viewed as an isolated system at minimal free energy. Instead, the interfacial dynamics become intimately connected to those of the separated homogeneous phases. Hence, the interface transitions toward a state in local equilibrium whereupon it becomes a dense-fluid mixing layer. A new conceptual view of a transitional liquid injection process emerges from a transition time scale analysis. Close to the nozzle exit, the two-phase interface still remains largely intact and more classic two-phase processes prevail as a consequence. Further downstream, however, the transition to dense-fluid mixing generally occurs before the liquid length is reached. As a result, the significance of the presented modeling expressions is established by a direct comparison to a reduced model, which utilizes widely applied approximations but fundamentally fails to capture the physical complexity discussed in this paper.« less

Understanding the breakdown of classic two-phase theory and spray atomization at engine-relevant conditions

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

Dahms, Rainer N., E-mail: Rndahms@sandia.gov

A generalized framework for multi-component liquid injections is presented to understand and predict the breakdown of classic two-phase theory and spray atomization at engine-relevant conditions. The analysis focuses on the thermodynamic structure and the immiscibility state of representative gas-liquid interfaces. The most modern form of Helmholtz energy mixture state equation is utilized which exhibits a unique and physically consistent behavior over the entire two-phase regime of fluid densities. It is combined with generalized models for non-linear gradient theory and for liquid injections to quantify multi-component two-phase interface structures in global thermal equilibrium. Then, the Helmholtz free energy is minimized whichmore » determines the interfacial species distribution as a consequence. This minimal free energy state is demonstrated to validate the underlying assumptions of classic two-phase theory and spray atomization. However, under certain engine-relevant conditions for which corroborating experimental data are presented, this requirement for interfacial thermal equilibrium becomes unsustainable. A rigorously derived probability density function quantifies the ability of the interface to develop internal spatial temperature gradients in the presence of significant temperature differences between injected liquid and ambient gas. Then, the interface can no longer be viewed as an isolated system at minimal free energy. Instead, the interfacial dynamics become intimately connected to those of the separated homogeneous phases. Hence, the interface transitions toward a state in local equilibrium whereupon it becomes a dense-fluid mixing layer. A new conceptual view of a transitional liquid injection process emerges from a transition time scale analysis. Close to the nozzle exit, the two-phase interface still remains largely intact and more classic two-phase processes prevail as a consequence. Further downstream, however, the transition to dense-fluid mixing generally occurs before the liquid length is reached. The significance of the presented modeling expressions is established by a direct comparison to a reduced model, which utilizes widely applied approximations but fundamentally fails to capture the physical complexity discussed in this paper.« less

Understanding the breakdown of classic two-phase theory and spray atomization at engine-relevant conditions

DOE PAGES

Dahms, Rainer N.

2016-04-26

A generalized framework for multi-component liquid injections is presented to understand and predict the breakdown of classic two-phase theory and spray atomization at engine-relevant conditions. The analysis focuses on the thermodynamic structure and the immiscibility state of representative gas-liquid interfaces. The most modern form of Helmholtz energy mixture state equation is utilized which exhibits a unique and physically consistent behavior over the entire two-phase regime of fluid densities. It is combined with generalized models for non-linear gradient theory and for liquid injections to quantify multi-component two-phase interface structures in global thermal equilibrium. Then, the Helmholtz free energy is minimized whichmore » determines the interfacial species distribution as a consequence. This minimal free energy state is demonstrated to validate the underlying assumptions of classic two-phase theory and spray atomization. However, under certain engine-relevant conditions for which corroborating experimental data are presented, this requirement for interfacial thermal equilibrium becomes unsustainable. A rigorously derived probability density function quantifies the ability of the interface to develop internal spatial temperature gradients in the presence of significant temperature differences between injected liquid and ambient gas. Then, the interface can no longer be viewed as an isolated system at minimal free energy. Instead, the interfacial dynamics become intimately connected to those of the separated homogeneous phases. Hence, the interface transitions toward a state in local equilibrium whereupon it becomes a dense-fluid mixing layer. A new conceptual view of a transitional liquid injection process emerges from a transition time scale analysis. Close to the nozzle exit, the two-phase interface still remains largely intact and more classic two-phase processes prevail as a consequence. Further downstream, however, the transition to dense-fluid mixing generally occurs before the liquid length is reached. As a result, the significance of the presented modeling expressions is established by a direct comparison to a reduced model, which utilizes widely applied approximations but fundamentally fails to capture the physical complexity discussed in this paper.« less

Crack Repair in Aerospace Aluminum Alloy Panels by Cold Spray

NASA Astrophysics Data System (ADS)

Cavaliere, P.; Silvello, A.

2017-04-01

The cold-spray process has recently been recognized as a very useful tool for repairing metallic sheets, achieving desired adhesion strengths when employing optimal combinations of material process parameters. We present herein the possibility of repairing cracks in aluminum sheets by cold spray. A 2099 aluminum alloy panel with a surface 30° V notch was repaired by cold spraying of 2198 and 7075 aluminum alloy powders. The crack behavior of V-notched sheets subjected to bending loading was studied by finite-element modeling (FEM) and mechanical experiments. The simulations and mechanical results showed good agreement, revealing a remarkable K factor reduction, and a consequent reduction in crack nucleation and growth velocity. The results enable prediction of the failure initiation locus in the case of repaired panels subjected to bending loading and deformation. The stress concentration was quantified to show how the residual stress field and failure are affected by the mechanical properties of the sprayed materials and by the geometrical and mechanical properties of the interface. It was demonstrated that the crack resistance increases more than sevenfold in the case of repair using AA2198 and that cold-spray repair can contribute to increased global fatigue life of cracked structures.

Supersonic Plasma Spray Deposition of CoNiCrAlY Coatings on Ti-6Al-4V Alloy

NASA Astrophysics Data System (ADS)

Caliari, F. R.; Miranda, F. S.; Reis, D. A. P.; Essiptchouk, A. M.; Filho, G. P.

2017-06-01

Plasma spray is a versatile technology used for production of environmental and thermal barrier coatings, mainly in the aerospace, gas turbine, and automotive industries, with potential application in the renewable energy industry. New plasma spray technologies have been developed recently to produce high-quality coatings as an alternative to the costly low-pressure plasma-spray process. In this work, we studied the properties of as-sprayed CoNiCrAlY coatings deposited on Ti-6Al-4V substrate with smooth surface ( R a = 0.8 μm) by means of a plasma torch operating in supersonic regime at atmospheric pressure. The CoNiCrAlY coatings were evaluated in terms of their surface roughness, microstructure, instrumented indentation, and phase content. Static and dynamic depositions were investigated to examine their effect on coating characteristics. Results show that the substrate surface velocity has a major influence on the coating properties. The sprayed CoNiCrAlY coatings exhibit low roughness ( R a of 5.7 μm), low porosity (0.8%), excellent mechanical properties ( H it = 6.1 GPa, E it = 155 GPa), and elevated interface toughness (2.4 MPa m1/2).

A new simple and rapid LC-ESI-MS/MS method for quantification of plasma oxysterols as dimethylaminobutyrate esters. Its successful use for the diagnosis of Niemann-Pick type C disease.

PubMed

Boenzi, Sara; Deodato, Federica; Taurisano, Roberta; Martinelli, Diego; Verrigni, Daniela; Carrozzo, Rosalba; Bertini, Enrico; Pastore, Anna; Dionisi-Vici, Carlo; Johnson, David W

2014-11-01

Two oxysterols, cholestan-3β,5α,6β-triol (C-triol) and 7-ketocholesterol (7-KC), have been recently proposed as diagnostic markers of Niemann-Pick type C (NP-C) disease, representing a potential alternative diagnostic tool to the more invasive and time consuming filipin test in cultured fibroblasts. Usually, the oxysterols are detected and quantified by liquid chromatography-tandem mass spectrometry (LC-MS/MS) method using atmospheric pressure chemical ionization (APCI) or electro-spray-ionization (ESI) sources, after a variety of derivatization procedures to enhance sensitivity. We developed a sensitive LC-MS/MS method to quantify the oxysterols in plasma as dimethylaminobutyrate ester, suitable for ESI analysis. This method, with an easy liquid-phase extraction and a short derivatization procedure, has been validated to demonstrate specificity, linearity, recovery, lowest limit of quantification, accuracy and precision. The assay was linear over a concentration range of 0.5-200ng/mL for C-triol and 1.0-200ng/mL for 7-KC. Intra-day and inter-day coefficients of variation (CV%) were <15% for both metabolites. Receiver operating characteristic analysis estimates that the area under curve was 0.998 for C-triol, and 0.972 for 7-KC, implying a significant discriminatory power for the method in this patient population of both oxysterols. In summary, our method provides a simple, rapid and non-invasive diagnostic tool for the biochemical diagnosis of NP-C disease. Copyright © 2014 Elsevier B.V. All rights reserved.

Simultaneous determination of eight metabolites of organophosphate and pyrethroid pesticides in urine.

PubMed

Guo, Xin Y; Sun, Li S; Huang, Meng Y; Xu, Wei L; Wang, Ying; Wang, Na

2017-01-02

A simultaneous method for quantifying eight metabolites of organophosphate pesticides and pyrethroid pesticides in urine samples has been established. The analytes were extracted using liquid-liquid extraction coupled with WCX solid phase extraction (SPE) cartridges. Eight metabolites were chemically derivatized before analysis using gas chromatography-tandem mass spectrometry (GC-MS-MS). The separation was performed on a HP-5MS capillary column (30 m × 0.25 mm × 0.25 µm) with temperature programming. The detection was performed under electro-spray ionization (ESI) in multiple reaction monitoring (MRM) mode. An internal standard method was used. The extraction solvent, types of SPE cartridges and eluents were optimized by comparing the sample recoveries under different conditions. The results showed that the calibration curves of the five organophosphorus pesticides metabolites were linear in the range of 0.2-200 μg/L (r 2 ≥ 0.992) and that of the three pyrethroid pesticides metabolites were linear in the range of 0.025-250 μg/L (r 2 ≥ 0.991). The limits of detection (LODs, S/N ≥ 3) and the limits of quantification (LOQs, S/N ≥ 10) of the eight metabolites were 0.008-0.833 μg/L and 0.25-2.5 μg/L, respectively. The recoveries of the eight metabolites ranged from 54.08% to 82.49%. This efficient, stable, and cost-effective method is adequate to handle the large number of samples required for surveying the exposure level of organophosphorus and pyrethroid pesticides in the general population.

Simultaneous achiral-chiral analysis of pharmaceutical compounds using two-dimensional reversed phase liquid chromatography-supercritical fluid chromatography.

PubMed

Venkatramani, C J; Al-Sayah, Mohammad; Li, Guannan; Goel, Meenakshi; Girotti, James; Zang, Lisa; Wigman, Larry; Yehl, Peter; Chetwyn, Nik

2016-02-01

A new interface was designed to enable the coupling of reversed phase liquid chromatography (RPLC) and supercritical fluid chromatography (SFC). This online two-dimensional chromatographic system utilizing RPLC in the first dimension and SFC in the second was developed to achieve simultaneous achiral and chiral analysis of pharmaceutical compounds. The interface consists of an eight-port, dual-position switching valve with small volume C-18 trapping columns. The peaks of interest eluting from the first RPLC dimension column were effectively focused as sharp concentration pulses on small volume C-18 trapping column/s and then injected onto the second dimension SFC column. The first dimension RPLC separation provides the achiral purity result, and the second dimension SFC separation provides the chiral purity result (enantiomeric excess). The results are quantitative enabling simultaneous achiral, chiral analysis of compounds. The interface design and proof of concept demonstration are presented. Additionally, comparative studies to conventional SFC and case studies of the applications of 2D LC-SFC in pharmaceutical analysis is presented. Copyright © 2015 Elsevier B.V. All rights reserved.

Atomization and dense-fluid breakup regimes in liquid rocket engines

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

Oefelein, Joseph; Dahms, Rainer Norbert Uwe

Until recently, modern theory has lacked a fundamentally based model to predict the operating pressures where classical sprays transition to dense-fluid mixing with diminished surface tension. In this paper, such a model is presented to quantify this transition for liquid-oxygen–hydrogen and n-decane–gaseous-oxygen injection processes. The analysis reveals that respective molecular interfaces break down not necessarily because of vanishing surface tension forces but instead because of the combination of broadened interfaces and a reduction in mean free molecular path. When this occurs, the interfacial structure itself enters the continuum regime, where transport processes rather than intermolecular forces dominate. Using this model,more » regime diagrams for the respective systems are constructed that show the range of operating pressures and temperatures where this transition occurs. The analysis also reveals the conditions where classical spray dynamics persists even at high supercritical pressures. As a result, it demonstrates that, depending on the composition and temperature of the injected fluids, the injection process can exhibit either classical spray atomization, dense-fluid diffusion-dominated mixing, or supercritical mixing phenomena at chamber pressures encountered in state-of-the-art liquid rocket engines.« less

Atomization and dense-fluid breakup regimes in liquid rocket engines

DOE PAGES

Oefelein, Joseph; Dahms, Rainer Norbert Uwe

2015-04-20

Until recently, modern theory has lacked a fundamentally based model to predict the operating pressures where classical sprays transition to dense-fluid mixing with diminished surface tension. In this paper, such a model is presented to quantify this transition for liquid-oxygen–hydrogen and n-decane–gaseous-oxygen injection processes. The analysis reveals that respective molecular interfaces break down not necessarily because of vanishing surface tension forces but instead because of the combination of broadened interfaces and a reduction in mean free molecular path. When this occurs, the interfacial structure itself enters the continuum regime, where transport processes rather than intermolecular forces dominate. Using this model,more » regime diagrams for the respective systems are constructed that show the range of operating pressures and temperatures where this transition occurs. The analysis also reveals the conditions where classical spray dynamics persists even at high supercritical pressures. As a result, it demonstrates that, depending on the composition and temperature of the injected fluids, the injection process can exhibit either classical spray atomization, dense-fluid diffusion-dominated mixing, or supercritical mixing phenomena at chamber pressures encountered in state-of-the-art liquid rocket engines.« less

The effects of sea spray and atmosphere-wave coupling on air-sea exchange during a tropical cyclone

NASA Astrophysics Data System (ADS)

Garg, Nikhil; Kwee Ng, Eddie Yin; Narasimalu, Srikanth

2018-04-01

The study investigates the role of the air-sea interface using numerical simulations of Hurricane Arthur (2014) in the Atlantic. More specifically, the present study aims to discern the role ocean surface waves and sea spray play in modulating the intensity and structure of a tropical cyclone (TC). To investigate the effects of ocean surface waves and sea spray, numerical simulations were carried out using a coupled atmosphere-wave model, whereby a sea spray microphysical model was incorporated within the coupled model. Furthermore, this study also explores how sea spray generation can be modelled using wave energy dissipation due to whitecaps; whitecaps are considered as the primary mode of spray droplets generation at hurricane intensity wind speeds. Three different numerical simulations including the sea- state-dependent momentum flux, the sea-spray-mediated heat flux, and a combination of the former two processes with the sea-spray-mediated momentum flux were conducted. The foregoing numerical simulations were evaluated against the National Data Buoy Center (NDBC) buoy and satellite altimeter measurements as well as a control simulation using an uncoupled atmosphere model. The results indicate that the model simulations were able to capture the storm track and intensity: the surface wave coupling results in a stronger TC. Moreover, it is also noted that when only spray-mediated heat fluxes are applied in conjunction with the sea-state-dependent momentum flux, they result in a slightly weaker TC, albeit stronger compared to the control simulation. However, when a spray-mediated momentum flux is applied together with spray heat fluxes, it results in a comparably stronger TC. The results presented here allude to the role surface friction plays in the intensification of a TC.

Hydrazine-Free Solution-Deposited CuIn(S,Se)2 Solar Cells by Spray Deposition of Metal Chalcogenides.

PubMed

Arnou, Panagiota; van Hest, Maikel F A M; Cooper, Carl S; Malkov, Andrei V; Walls, John M; Bowers, Jake W

2016-05-18

Solution processing of semiconductors, such as CuInSe2 and its alloys (CIGS), can significantly reduce the manufacturing costs of thin film solar cells. Despite the recent success of solution deposition approaches for CIGS, toxic reagents such as hydrazine are usually involved, which introduce health and safety concerns. Here, we present a simple and safer methodology for the preparation of high-quality CuIn(S, Se)2 absorbers from metal sulfide solutions in a diamine/dithiol mixture. The solutions are sprayed in air, using a chromatography atomizer, followed by a postdeposition selenization step. Two different selenization methods are explored resulting in power conversion efficiencies of up to 8%.

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

Shoup, R.W.; Long, F.; Martin, T.H.

Sandia has developed PBFA-Z, a 20-MA driver for z-pinch experiments by replacing the water lines, insulator stack. and MITLs on PBFA II with hardware of a new design. The PBFA-Z accelerator was designed to deliver 20 MA to a 15-mg z-pinch load in 100 ns. The accelerator was modeled using circuit codes to determine the time-dependent voltage and current waveforms at the input and output of the water lines, the insulator stack, and the MITLs. The design of the vacuum insulator stack was dictated by the drive voltage, the electric field stress and grading requirements, the water line and MITLmore » interface requirements, and the machine operations and maintenance requirements. The insulator stack consists of four separate modules, each of a different design because of different voltage drive and hardware interface requirements. The shape of the components in each module, i.e., grading rings, insulator rings, flux excluders, anode and cathode conductors, and the design of the water line and MITL interfaces, were optimized by using the electrostatic analysis codes, ELECTRO and JASON. The time-dependent performance of the insulator stacks was evaluated using IVORY, a 2-D PIC code. This paper will describe the insulator stack design, present the results of the ELECTRO and IVORY analyses, and show the results of the stack measurements.« less

Methods of Making Z-Shielding

NASA Technical Reports Server (NTRS)

Thomsen, III, Donald Laurence (Inventor); Cano, Roberto J. (Inventor); Jensen, Brian J. (Inventor); Hales, Stephen J. (Inventor); Alexa, Joel A. (Inventor)

2014-01-01

Methods of building Z-graded radiation shielding and covers. In one aspect, the method includes: providing a substrate surface having about medium Z-grade; plasma spraying a first metal having higher Z-grade than the substrate surface; and infusing a polymer layer to form a laminate. In another aspect, the method includes electro/electroless plating a first metal having higher Z-grade than the substrate surface. In other aspects, the methods include improving an existing electronics enclosure to build a Z-graded radiation shield by applying a temperature controller to at least part of the enclosure and affixing at least one layer of a first metal having higher Z-grade from the enclosure.

Comparison of PCR/Electron Spray Ionization-Time-of-Flight-Mass Spectrometry versus Traditional Clinical Microbiology for Active Surveillance of Organisms Contaminating High-Use Surfaces in a Burn Intensive Care Unit, an Orthopedic Ward and Healthcare Workers

DTIC Science & Technology

2012-10-10

were designed with anterooms and universal gowns and gloves are used) and ten from the orthopedic ward. Nine rooms in the burn ICU had sam- ple...PCR amplification was carried out as per Ecker et al [25]. The PCR products were then desalted in a 96-well plate format and sequentially electro...organisms by site. Based on these data, no obvious target for increased infection control efforts was seen in the study units. As this study was designed

Influence of drying method on the surface energy of cellulose nanofibrils determined by inverse gas chromatography

Treesearch

Yucheng Peng; Douglas J. Gardner; Yousoo Han; Zhiyong Cai; Mandla A. Tshabalala

2013-01-01

Research and development of the renewable nanomaterial cellulose nanofibrils (CNFs) has received considerable attention. The effect of drying on the surface energy of CNFs was investigated. Samples of nanofibrillated cellulose (NFC) and cellulose nanocrystals (CNC) were each subjected to four separate drying methods: air-drying, freeze-drying, spray-drying, and...

Patterning of a-C DLC films: exploration of an aqueous electro-oxidative mechanism

NASA Astrophysics Data System (ADS)

Mühl, Thomas; Myhra, Sverre

2007-06-01

Conducting ion-beam assisted CVD deposited a-C type DLC films can be patterned electro-oxidatively by masked and maskless probe-induced STM-based lithography. The former constitutes a parallel rapid processing technology, with the tip acting as a distant stationary electrode. The latter is a higher spatial resolution serial technology, with the tip defining a travelling local electro-chemical cell. The mechanism is based on electro-oxidative conversion of solid carbon to gaseous CO or CO2 in the presence of an aqueous phase, either as a bulk fluid or as a thin adsorbed film. The process is constrained kinetically in the early stages by limitations on charge transport through the surface barrier at the fluid-to-solid interface and subsequently by the availability of oxidants and by their transport to reactive sites. The as-received surface is terminated by chemisorbed oxygen, leading to the formation of an insulating surface barrier. The threshold potential for initiation of conversion depends on the width of the barrier. The results may have implications for new technologies exploiting the properties of carbon-based materials, but may also add to the present understanding of the electrochemistry of carbon solids.

Spray-applied waterproofing membranes: effective solution for safe and durable tunnel linings?

NASA Astrophysics Data System (ADS)

Pisova, Barbora; Hilar, Matous

2017-09-01

What is the perfect tunnel lining? Cost efficient, easy and fast to build with acceptable environmental impact? How to construct a watertight and safe tunnel lining? Would it be possible to apply a waterproofing system directly onto the rock face just after the tunnel face opening? This might be the system of the future enabling all concrete applied to the rock face to remain permanent. For now though, we would like to focus on an optimisation and examination of currently available technologies and materials, such as tunnel linings with the use of spray-applied waterproofing membranes. In this paper, the failure mechanisms of a tunnel lining with a spray-applied waterproofing membrane are described, the behaviour of spray-applied waterproofing membrane under various conditions (dry, moist, wet) is challenged and the possibilities of interface numerical modelling are presented. Tunnel lining design is mainly dependent on the geological and hydrological conditions in the considered area. The application of tunnel linings with spray-applied waterproofing membrane in both hard rock and soft ground tunnelling, are studied.

Structure characterization and wear performance of NiTi thermal sprayed coatings

NASA Astrophysics Data System (ADS)

Cinca, N.; Isalgué, A.; Fernández, J.; Guilemany, J. M.

2010-08-01

NiTi shape memory alloy (SMA) has been studied for many years for its shape memory and pseudoelastic properties, as well as its biocompatibility, which make it suitable for many biomedical applications. However, SMA NiTi is also interesting for relevant wear resistance near the transition temperature which, along with its high oxidation and corrosion resistance, suggests its use as a coating to increase the lifetime of some components. Also, whereas bulk material properties have been characterized in respect of the nominal composition, manufacturing methods and thermo-mechanical treatments, NiTi overlays have been investigated much less. Most existent works in this field specifically deal with magnetron sputtering technology for thin films and its use in micro-devices (micro-electro-mechanical systems, MEMS), just some works refer to vacuum plasma spraying (VPS) for thicker coatings. The present paper explores and compares the microstructure and wear-related properties of coatings obtained from atomized NiTi powders, by VPS as well as by atmospheric plasma spraying (APS) and high velocity oxygen fuel (HVOF) techniques. In the present case, the wear behaviour of the NiTi deposits has been studied by rubber-wheel equipment and ball-on-disk tests. The results obtained at room temperature show that the APS-quenched coatings exhibit a preferential dry sliding wear mechanism, while the VPS and HVOF coatings show an abrasive mechanism.

Development and Evaluation of a Combined Cultivator and Band Sprayer with a Row-Centering RTK-GPS Guidance System

PubMed Central

Perez-Ruiz, Manuel; Carballido, Jacob; Agüera, Juan; Rodríguez-Lizana, Antonio

2013-01-01

Typically, low-pressure sprayers are used to uniformly apply pre- and post-emergent herbicides to control weeds in crop rows. An innovative machine for weed control in inter-row and intra-row areas, with a unique combination of inter-row cultivation tooling and intra-row band spraying for six rows and an electro-hydraulic side-shift frame controlled by a GPS system, was developed and evaluated. Two weed management strategies were tested in the field trials: broadcast spraying (the conventional method) and band spraying with mechanical weed control using RTK-GPS (the experimental method). This approach enabled the comparison between treatments from the perspective of cost savings and efficacy in weed control for a sugar beet crop. During the 2010–2011 season, the herbicide application rate (112 L ha−1) of the experimental method was approximately 50% of the conventional method, and thus a significant reduction in the operating costs of weed management was achieved. A comparison of the 0.2-trimmed means of weed population post-treatment showed that the treatments achieved similar weed control rates at each weed survey date. Sugar beet yields were similar with both methods (p = 0.92). The use of the experimental equipment is cost-effective on ≥20 ha of crops. These initial results show good potential for reducing herbicide application in the Spanish beet industry. PMID:23478600

Development and evaluation of a combined cultivator and band sprayer with a row-centering RTK-GPS guidance system.

PubMed

Perez-Ruiz, Manuel; Carballido, Jacob; Agüera, Juan; Rodríguez-Lizana, Antonio

2013-03-11

Typically, low-pressure sprayers are used to uniformly apply pre- and post-emergent herbicides to control weeds in crop rows. An innovative machine for weed control in inter-row and intra-row areas, with a unique combination of inter-row cultivation tooling and intra-row band spraying for six rows and an electro-hydraulic side-shift frame controlled by a GPS system, was developed and evaluated. Two weed management strategies were tested in the field trials: broadcast spraying (the conventional method) and band spraying with mechanical weed control using RTK-GPS (the experimental method). This approach enabled the comparison between treatments from the perspective of cost savings and efficacy in weed control for a sugar beet crop. During the 2010-2011 season, the herbicide application rate (112 L ha(-1)) of the experimental method was approximately 50% of the conventional method, and thus a significant reduction in the operating costs of weed management was achieved. A comparison of the 0.2-trimmed means of weed population post-treatment showed that the treatments achieved similar weed control rates at each weed survey date. Sugar beet yields were similar with both methods (p = 0.92). The use of the experimental equipment is cost-effective on ≥20 ha of crops. These initial results show good potential for reducing herbicide application in the Spanish beet industry.

Real time monitoring of environmental crack growth in BWRs

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

Hale, D.; Diehl, C.G.

1988-01-01

A comprehensive field test program was recently completed at several Boiling Water Reactors (BWR) to quantify the effect of coolant impurities on the initiation and growth of stress corrosion cracks. A new technology was utilized which allows for real time monitoring of stress corrosion crack growth rates. The BWR environments were characterized using Ion Chromatography and Electro Chemical Potential (ECP) measurements. The effects of typical water chemistry transients and startups were quantified.

A multi-targeted liquid chromatography-mass spectrometry screening procedure for the detection in human urine of drugs non-prohibited in sport commonly used by the athletes.

PubMed

Mazzarino, Monica; Cesarei, Lorenzo; de la Torre, Xavier; Fiacco, Ilaria; Robach, Paul; Botrè, Francesco

2016-01-05

This work presents an analytical method for the simultaneous analysis in human urine of 38 pharmacologically active compounds (19 benzodiazepine-like substances, 7 selective serotonin reuptake inhibitors, 4 azole antifungal drugs, 5 inhibitors of the phosphodiesterases type 4 and 3 inhibitors of the phosphodiesterase type 5) by liquid-chromatography coupled with tandem mass spectrometry. The above substances classes include both the most common "non banned" drugs used by the athletes (based on the information reported on the "doping control form") and those drugs who are suspected to be performance enhancing and/or act as masking agents in particular conditions. The chromatographic separation was performed by a reverse-phase octadecyl column using as mobile phases acetonitrile and ultra-purified water, both with 0.1% formic acid. The detection was carried out using a triple quadrupole mass spectrometric analyser, positive electro-spray as ionization source and selected reaction monitoring as acquisition mode. Sample pre-treatment consisted in an enzymatic hydrolysis followed by a liquid-liquid extraction in neutral field using tert-butyl methyl-ether. The analytical procedure, once developed, was validated in terms of sensitivity (lower limits of detection in the range of 1-50 ng mL(-1)), specificity (no interferences were detected at the retention time of all the analytes under investigation), recovery (≥60% with a satisfactory repeatability, CV % lower than 10), matrix effect (lower than 30%) and reproducibility of retention times (CV% lower than 0.1) and of relative abundances (CV% lower than 15). The performance and the applicability of the method was evaluated by analyzing real samples containing benzodiazepines (alprazolam, diazepam, zolpidem or zoplicone) or inhibitors of the phosphodiesterases type 5 (sildenafil or vardenafil) and samples obtained incubating two of the phosphodiesterases type 4 studied (cilomilast or roflumilast) with pooled human liver microsomes. All the parent compounds, together with their main phase I metabolites, were clearly detected using the analytical procedures here developed. Copyright © 2015 Elsevier B.V. All rights reserved.

Current limit diagrams for dendrite formation in solid-state electrolytes for Li-ion batteries

NASA Astrophysics Data System (ADS)

Raj, R.; Wolfenstine, J.

2017-03-01

We build upon the concept that nucleation of lithium dendrites at the lithium anode-solid state electrolyte interface is instigated by the higher resistance of grain boundaries that raises the local electro-chemical potential of lithium, near the lithium-electrode. This excess electro-chemo-mechanical potential, however, is reduced by the mechanical back stress generated when the dendrite is formed within the electrolyte. These parameters are coalesced into an analytical model that prescribes a specific criterion for dendrite formation. The results are presented in the form of current limit diagrams that show the "safe" and "fail" regimes for battery function. A higher conductivity of the electrolyte can reduce dendrite formation.

Research and development of plasma sprayed tungsten coating on graphite and copper substrates

NASA Astrophysics Data System (ADS)

Liu, Xiang; Zhang, Fu; Tao, Shunyan; Cao, Yunzhen; Xu, Zengyu; Liu, Yong; Noda, N.

2007-06-01

Vacuum plasma sprayed tungsten coating on graphite and copper substrates has been prepared. VPS-W coated graphite has multilayered silicon and tungsten interface pre-deposited by physical vapor deposition (PVD) and VPS-W coated copper has graded transition interlayer. VPS-W coating was characterized, and then the high heat flux properties of the coating were examined. Experimental results indicated that both VPS-W coated graphite and VPS-W coated copper could endure 1000 cycles without visible failure under a heat flux of approximately 5 MW/m2 absorbed power density and 5 s pulse duration. A comparison between the present VPS-W coated graphite and VPS-W coated carbon fiber composite (CX-2002U) with Re interface made by Plansee Aktiengesllshaft was carried out. Results show that both Re and Si are suitable as intermediate layer for tungsten coating on carbon substrates.

Microstructure Changes of Plasma Spraying Tungsten Coatings on Cfc after Different Temperature Annealing

NASA Astrophysics Data System (ADS)

Liu, X.; Tamura, S.; Tokunaga, K.; Yoshida, N.; Noda, N.

2003-06-01

Thermal behaviors of tungsten coating of 0.5 mm thick with multi-layers interface of tungsten (W) and rhenium (Re) coated on CFC (CX-2002U) substrate by vacuum plasma spraying (VPS) technique were examined by annealing with an electron beam thermal load facility between 1200 °C and 2000 °C. Change of the microstructure was observed and its chemical composition was analyzed by EDS after annealing. It was observed that remarkable recrystallization of VPS-W occurred above 1400 °C. The structure of the multi-layers of W and Re become obscure by the mutual diffusion of W, Re and C above 1600°C and finally disappeared after annealing at 2000 °C for one hour. Very hard tungsten carbides are formed at the interface above 1600 °C and they were broadening with increasing annealing temperature and time.

Interfacial chemistry of zinc anodes for reinforced concrete structures

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

Covino, B.S. Jr.; Bullard, S.J.; Cramer, S.D.

1997-12-01

Thermally-sprayed zinc anodes are used in both galvanic and impressed current cathodic protection systems for reinforced concrete structures. The Albany Research Center, in collaboration with the Oregon Department of Transportation, has been studying the effect of electrochemical aging on the bond strength of zinc anodes for bridge cathodic protection systems. Changes in anode bond strength and other anode properties can be explained by the chemistry of the zinc-concrete interface. The chemistry of the zinc-concrete interface in laboratory electrochemical aging studies is compared with that of several bridges with thermal-sprayed zinc anodes and which have been in service for 5 tomore » 10 years using both galvanic and impressed current cathodic protection systems. The bridges are the Cape Creek Bridge on the Oregon coast and the East Camino Undercrossing near Placerville, CA. Also reported are interfacial chemistry results for galvanized steel rebar from the 48 year old Longbird Bridge in Bermuda.« less

Relationships between spray parameters, microstructures and ultrasonic cavitation erosion behavior of HVOF sprayed Fe-based amorphous/nanocrystalline coatings.

PubMed

Qiao, Lei; Wu, Yuping; Hong, Sheng; Zhang, Jianfeng; Shi, Wei; Zheng, Yugui

2017-11-01

Fe-based amorphous/nanocrystalline coatings were prepared on the AISI 321 steel substrate by the high-velocity oxygen-fuel (HVOF) thermal spraying technology. The effect of selected parameters (oxygen flow, kerosene flow and spray distance) on the cavitation erosion resistance (denoted as Rc) of the coating were investigated by using the Taguchi method. Statistical tools such as design of experiments (DOE), signal-to-noise (S/N) ratio and analysis of variance (ANOVA) were used to meet the expected objective. It was concluded that the kerosene flow had greater influence on the Rc of the coating and followed by the spray distance and the oxygen flow, respectively. The optimum spray parameters (OSP) were 963L/min for the oxygen flow, 28L/h for the kerosene flow, and 330mm for the spray distance. The Rc of the coating increased with the increase of hardness or the decrease of porosity, and the hardness had a greater influence on Rc than the porosity. The Fe-based coating deposited under the OSP exhibited the best cavitation erosion resistance in distilled water. The cracks initiated at the edge of the pores and the interfaces between the un-melted or half-melted particles, and finally leaded to the delamination of the coating. Copyright © 2017 Elsevier B.V. All rights reserved.

An update on coating/manufacturing techniques of microneedles.

PubMed

Tarbox, Tamara N; Watts, Alan B; Cui, Zhengrong; Williams, Robert O

2017-12-29

Recently, results have been published for the first successful phase I human clinical trial investigating the use of dissolving polymeric microneedles… Even so, further clinical development represents an important hurdle that remains in the translation of microneedle technology to approved products. Specifically, the potential for accumulation of polymer within the skin upon repeated application of dissolving and coated microneedles, combined with a lack of safety data in humans, predicates a need for further clinical investigation. Polymers are an important consideration for microneedle technology-from both manufacturing and drug delivery perspectives. The use of polymers enables a tunable delivery strategy, but the scalability of conventional manufacturing techniques could arguably benefit from further optimization. Micromolding has been suggested in the literature as a commercially viable means to mass production of both dissolving and swellable microneedles. However, the reliance on master molds, which are commonly manufactured using resource intensive microelectronics industry-derived processes, imparts notable material and design limitations. Further, the inherently multi-step filling and handling processes associated with micromolding are typically batch processes, which can be challenging to scale up. Similarly, conventional microneedle coating processes often follow step-wise batch processing. Recent developments in microneedle coating and manufacturing techniques are highlighted, including micromilling, atomized spraying, inkjet printing, drawing lithography, droplet-born air blowing, electro-drawing, continuous liquid interface production, 3D printing, and polyelectrolyte multilayer coating. This review provides an analysis of papers reporting on potentially scalable production techniques for the coating and manufacturing of microneedles.

Effects of inorganic seeds on secondary organic aerosol formation from photochemical oxidation of acetone in a chamber

NASA Astrophysics Data System (ADS)

Ge, Shuangshuang; Xu, Yongfu; Jia, Long

2017-12-01

Photochemical oxidations of acetone were studied under different inorganic seed (NaCl, (NH4)2SO4 and NaNO3) conditions in a self-made chamber. The results show that no secondary organic aerosol (SOA) can be formed in the experiments either in the absence of artificially added seed particles or in the presence of solid status of the added particles. Liquid water content is the key factor for the formation of SOA in the experiments with seeds. The amount of SOA was only about 4-7 μg m-3 in the experiments with the initial acetone of ∼15 ppm under different seed conditions. The analysis of SOA compositions by Exactive-Orbitrap mass spectrometer equipped with electro-spray interface (ESI-MS) shows that chlorine-containing and sulfur-containing compounds were detected in SOA formed from the experiments with NaCl and (NH4)2SO4 seeds, respectively, which were not identified in SOA from those with NaNO3. The compositions of SOA were mainly esters, organonitrates, hydroperoxides, etc. It is concluded that inorganic seed particles participated into the formation of SOA. Acetone SOA was mainly formed in the aqueous phase in which dissolved SOA precursors underwent further oxidation reactions, esterification reactions and/or radical-radical reactions. Our experiments further demonstrate that low-molecular-weight VOCs, such as acetone, can form SOA under certain conditions in the atmosphere, although their contributions to SOA may not be large.

[Preparation of panax notoginseng saponins-tanshinone H(A) composite method for pulmonary delivery with spray-drying method and its characterization].

PubMed

Wang, Hua-Mei; Fu, Ting-Ming; Guo, Li-Wei

2013-02-01

To prepare panax notoginseng saponins-tanshinone II(A) composite particles for pulmonary delivery, in order to explore a dry powder particle preparation method ensuring synchronized arrival of multiple components of traditional Chinese medicine compounds at absorption sites. Panax notoginseng saponins-tanshinone II(A) composite particles were prepared with spray-drying method, and characterized by scanning electron microscopy (SEM), confocal laser scanning microscope (CLSM), X-ray diffraction (XRD), infrared analysis (IR), dry laser particle size analysis, high performance liquid chromatography (HPLC) and the aerodynamic behavior was evaluated by a Next Generation Impactor (NGI). The dry powder particles produced had narrow particle size distribution range and good aerodynamic behavior, and could realize synchronized administration of multiple components. The spray-drying method is used to combine traditional Chinese medicine components with different physical and chemical properties in the same particle, and product into traditional Chinese medicine compound particles in line with the requirements for pulmonary delivery.

Microstructure, Tensile Adhesion Strength and Thermal Shock Resistance of TBCs with Different Flame-Sprayed Bond Coat Materials Onto BMI Polyimide Matrix Composite

NASA Astrophysics Data System (ADS)

Abedi, H. R.; Salehi, M.; Shafyei, A.

2017-10-01

In this study, thermal barrier coatings (TBCs) composed of different bond coats (Zn, Al, Cu-8Al and Cu-6Sn) with mullite top coats were flame-sprayed and air-plasma-sprayed, respectively, onto bismaleimide matrix composites. These polyimide matrix composites are of interest to replace PMR-15, due to concerns about the toxicity of the MDA monomer from which PMR-15 is made. The results showed that pores and cracks appeared at the bond coat/substrate interface for the Al-bonded TBC because of its high thermal conductivity and diffusivity resulting in transferring of high heat flux and temperature to the polymeric substrate during top coat deposition. The other TBC systems due to the lower conductivity and diffusivity of bonding layers could decrease the adverse thermal effect on the polymer substrate during top coat deposition and exhibited adhesive bond coat/substrate interfaces. The tensile adhesion test showed that the adhesion strength of the coatings to the substrate is inversely proportional to the level of residual stress in the coatings. However, the adhesion strength of Al bond-coated sample decreased strongly after mullite top coat deposition due to thermal damage at the bond coat/substrate interface. TBC system with the Cu-6Sn bond coat exhibited the best thermal shock resistance, while Al-bonded TBC showed the lowest. It was inferred that thermal mismatch stresses and oxidation of the bond coats were the main factors causing failure in the thermal shock test.

Easy ambient sonic-spray ionization mass spectrometry combined with thin-layer chromatography.

PubMed

Haddad, Renato; Milagre, Humberto M S; Catharino, Rodrigo Ramos; Eberlin, Marcos N

2008-04-15

On-spot detection and analyte characterization on thin-layer chromatography (TLC) plates is performed via ambient desorption/ionization and (tandem) mass spectrometry detection, that is, via easy ambient sonic spray ionization mass spectrometry (EASI-MS). As proof-of-principle cases, mixtures of semipolar nitrogenated compounds as well as pharmaceutical drugs and vegetable oils have been tested. The technique has also been applied to monitor a chemical reaction of synthetic importance. EASI is the simplest and gentlest ambient ionization technique currently available, assisted solely by N2 (or air). It uses no voltages, no electrical discharges; no UV or laser beams, and no high temperature and is most easily implemented in all API mass spectrometers. TLC is also the simplest, fastest, and most easily performed chromatographic technique. TLC plus EASI-MS therefore provide a simple and advantageous combination of chromatographic separation and sensitive detection of the TLC spots as well as on-spot MS or MS/MS characterization. The favorable characteristics of TLC-EASI-MS indicate advantageous applications in several areas such as drug and oil analysis, phytochemistry and synthetic chemistry, forensics via reliable counterfeit detection, and quality control.

An investigation on the deicing of helicopter blades using shear horizontal guided waves

NASA Astrophysics Data System (ADS)

Ramanathan, Srinivasan

Despite all the advances that have made air travel safer than ever, the accumulation of ice on airplane and rotorcraft wings continues to be one of aviation's most challenging problems. Hence the presence of a reliable and efficient deicing or anti-icing system is imperative for their safe operation. The current method used to deice helicopter blades is similar to that available in automobile rear windows. These electro-thermal systems consist of heating coils that run along the span or chord of the rotor-blade. A current source connected via a slip ring configuration heats the coils, which in turn melt the ice on the surface. Due to their enormous power consumption, electro-thermal systems are generally configured to deice one foot of one blade at a time. This makes it hazardous to fly the helicopters under severe icing conditions. Even with the energy saving deicing procedure the electrical power required substantially exceeds the normal helicopter electrical system capacity, necessitating a large secondary electrical system with redundant, dual alternator features. The electro-thermal system for the Bell 412 helicopter weighed 162 lbs and required 26 kW of power for 2 blades! Various types of deicing systems were compared in chapter 1 and electromechanical systems were found to be the most energy efficient and practical for in-flight conditions. A novel approach of breaking the ice-substrate bonds by exceeding their adhesive strength using guided shear horizontal waves was chosen as the deicing mechanism. A comparison of the different electro-mechanical actuation systems pointed towards monolithic shear mode piezoelectric actuators as the choice that would satisfy the energy and dimensional requirements. A survey of literature on the mechanics of ice adhesion, in chapter 2, led to the selection of 1.42MPa as the target adhesive bond strength for the refrigerated icealuminum interface. The static adhesive strength of naturally occurring forms of ice such as rime ice and glaze ice to aluminum (0.12MPa and 0.4MPa respectively) is much lower than that of the refrigerated ice-aluminum adhesive strength (1.42MPa). Therefore, selecting the static adhesive strength of the refrigerated ice-aluminum interface as the bond strength to overcome would enable the system to deice rotor-blades under natural icing conditions. Equivalent circuit analysis was applied to the actuator, aluminum plate and ice layer system to determine an expression for the shear stress at the ice aluminum interface per unit excitation voltage supplied to the actuator and the corresponding electrical power consumed. All the parameters that affected the stress at the ice-aluminum interface were identified from the equivalent circuit model of the system. The parameters were split into control (can be actively changed by user) parameters and material (no user control over the variation of these parameter due to temperature and electric field) parameters. A statistical approach (Design of Experiments) was used to determine the control parameter settings that resulted in the maximum shear stress at the ice aluminum interface per unit actuator excitation voltage. A material parameter design of experiments was carried out to determine the effect of the deviation in the variable parameters on the stress at the ice-aluminum interface and actuator power consumption. A simplified approach to calculate the shear piezoelectric actuator losses under high excitation fields was presented. The experimental results indicated that the adhesive shear strength of the ice-aluminum bond under high frequency dynamic loads is much lower that its static adhesive strength. This was proved by the fact that the ice-aluminum interface bonds were broken at stress values of 0.73MPa as opposed to the target 1.42Mpa. This can be attributed to inherently stochastic nature of ice and the fact that the ice-aluminum bond fails at a much lower stress under dynamic loading as opposed to static loading. The shear mode actuator has a projected power consumption of 0.6kW for the twin bladed Bell 412 (assuming 6 actuators per foot per blade each consuming 50W) if deiced by station as opposed to 26kW for a corresponding electro-thermal system. The shear mode actuator has a projected power consumption of 3.6kW if both blades are deiced simultaneously over the desired length (1/3 rd span from the root) as required in severe icing conditions. The piezoelectric shear mode actuation system (estimated weight of 50 lbs with the actuators themselves accounting for less than 1 lb.) has the potential of delivering this performance while being 70% lighter than a comparable electro-thermal system (weight of 162 lbs). (Abstract shortened by UMI.)

Epitaxial Growth and Cracking Mechanisms of Thermally Sprayed Ceramic Splats

NASA Astrophysics Data System (ADS)

Chen, Lin; Yang, Guan-jun

2018-02-01

In the present study, the epitaxial growth and cracking mechanisms of thermally sprayed ceramic splats were explored. We report, for the first time, the epitaxial growth of various splat/substrate combinations at low substrate temperatures (100 °C) and large lattice mismatch (- 11.26%). Our results suggest that thermal spray deposition was essentially a liquid-phase epitaxy, readily forming chemical bonding. The interface temperature was also estimated. The results convincingly demonstrated that atoms only need to diffuse and rearrange over a sufficiently short range during extremely rapid solidification. Concurrently, severe cracking occurred in the epitaxial splat/substrate systems, which indicated high tensile stress was produced during splat deposition. The origin of the tensile stress was attributed to the strong constraint of the locally heated substrate by its cold surroundings.

Essential Factors Influencing the Bonding Strength of Cold-Sprayed Aluminum Coatings on Ceramic Substrates

NASA Astrophysics Data System (ADS)

Drehmann, R.; Grund, T.; Lampke, T.; Wielage, B.; Wüstefeld, C.; Motylenko, M.; Rafaja, D.

2018-02-01

The present work summarizes the most important results of a research project dealing with the comprehensive investigation of the bonding mechanisms between cold-sprayed Al coatings and various poly- and monocrystalline ceramic substrates (Al2O3, AlN, Si3N4, SiC, MgF2). Due to their exceptional combination of properties, metallized ceramics are gaining more and more importance for a wide variety of applications, especially in electronic engineering. Cold spray provides a quick, flexible, and cost-effective one-step process to apply metallic coatings on ceramic surfaces. However, since most of the existing cold-spray-related publications focus on metallic substrates, only very little is known about the bonding mechanisms acting between cold-sprayed metals and ceramic substrates. In this paper, the essential factors influencing the bonding strength in such composites are identified. Besides mechanical tensile strength testing, a thorough analysis of the coatings and especially the metal/ceramic interfaces was conducted by means of HRTEM, FFT, STEM, EDX, EELS, GAXRD, and EBSD. The influence of substrate material, substrate temperature, and particle size is evaluated. The results suggest that, apart from mechanical interlocking, the adhesion of cold-sprayed metallic coatings on ceramics is based on a complex interplay of different mechanisms such as quasiadiabatic shearing, static recrystallization, and heteroepitaxial growth.

Fabrication and characterization of plasma-sprayed HA/SiO(2) coatings for biomedical application.

PubMed

Morks, M F

2008-01-01

Fused silica powder has been mixed with hydroxyapatite (HA) powder and plasma sprayed by using gas tunnel-type plasma jet. The influence of silica content (10 wt% and 20 wt%) on the microstructure and mechanical properties of HA-silica coatings was investigated. For investigating the microstructure and mechanical properties of HA-silica coatings, SUS 304 stainless steel was used as substrate material. The spraying was carried out on roughened substrate in an atmospheric chamber. Scanning electron microscope micrographs of cross-sectioned HA/SiO(2) coatings showed that the sprayed HA coatings with 10 and 20 wt% SiO(2) have dense structure with low porosity compared to the pure HA coatings. On the other hand, as the amount of silica was increased the coatings became denser, harder and exhibited high abrasive wear resistance. The presence of silica significantly improved the adhesive strength of HA/SiO(2) coatings mainly due to the increase in bonding strength of the coating at the interface.

Effect of 2D WS2 Addition on Cold-Sprayed Aluminum Coating

NASA Astrophysics Data System (ADS)

Loganathan, Archana; Rengifo, Sara; Hernandez, Alexander Franco; Emirov, Yusuf; Zhang, Cheng; Boesl, Benjamin; Karthikeyan, Jeganathan; Agarwal, Arvind

2017-10-01

Tungsten disulfide (WS2) has excellent solid lubrication properties due to its 2D layered structure. This study focuses on depositing Al-2 wt.% WS2 composite coating by cold spray technique. The effect of WS2 addition on the microstructure, mechanical and tribological properties of the composite coatings is examined in the as-deposited and heat-treated conditions. After heat treatment, the coating density increased to 99% with improved intersplat bonding. The microhardness of the heat-treated Al-2 wt.% WS2 coating increased by 56% as compared to the as-sprayed coating. The wear resistance of heat-treated Al-2 wt.% WS2 coating improved by 75% with a synergistic reduction in the coefficient of friction (COF) by 51%. Transmission electron microscopy investigation reveals the presence of layered WS2 within aluminum splats with a strong interface. This study shows that cold spraying can be effectively used to integrate 2D layered WS2 as a solid lubricant in the metallic coatings.

Enhanced bonding property of cold-sprayed Zn-Al coating on interstitial-free steel substrate with a nanostructured surface layer

NASA Astrophysics Data System (ADS)

Liang, Y. L.; Wang, Z. B.; Zhang, J.; Zhang, J. B.; Lu, K.

2016-11-01

By means of surface mechanical attrition treatment (SMAT), a gradient nanostructured surface layer was fabricated on a hot-rolled interstitial-free steel plate. A Zn-Al coating was subsequently deposited on the SMAT sample by using cold spray process. The bonding property of the coating on the SMAT substrate was compared with that on the coarse-grained (CG) sample. Stud-pull tests showed that the bonding strength in the as-sprayed SMAT sample is ∼30% higher than that in the as-sprayed CG sample. No further improvement in bonding strength was achieved in the coated SMAT sample after annealing at 400 °C, mostly due to the formation of cracks and intermetallic compounds at the coating/substrate interface in an earlier stage (<30 min) and in a final stage (>90 min), respectively. The enhanced bonding property of the Zn-Al coating on the SMAT sample might be related with the promoted atomic diffusion and hardness in the nanostructured surface layer.

Polarization-Insensitive Surface Plasmon Polarization Electro-Absorption Modulator Based on Epsilon-Near-Zero Indium Tin Oxide.

PubMed

Jin, Lin; Wen, Long; Liang, Li; Chen, Qin; Sun, Yunfei

2018-02-03

CMOS-compatible plasmonic modulators operating at the telecom wavelength are significant for a variety of on-chip applications. Relying on the manipulation of the transverse magnetic (TM) mode excited on the metal-dielectric interface, most of the previous demonstrations are designed to response only for specific polarization state. In this case, it will lead to a high polarization dependent loss, when the polarization-sensitive modulator integrates to a fiber with random polarization state. Herein, we propose a plasmonic modulator utilizing a metal-oxide indium tin oxide (ITO) wrapped around the silicon waveguide and investigate its optical modulation ability for both the vertical and horizontal polarized guiding light by tuning electro-absorption of ITO with the field-induced carrier injection. The electrically biased modulator with electron accumulated at the ITO/oxide interface allows for epsilon-near-zero (ENZ) mode to be excited at the top or lateral portion of the interface depending on the polarization state of the guiding light. Because of the high localized feature of ENZ mode, efficient electro-absorption can be achieved under the "OFF" state of the device, thus leading to large extinction ratio (ER) for both polarizations in our proposed modulator. Further, the polarization-insensitive modulation is realized by properly tailoring the thickness of oxide in two different stacking directions and therefore matching the ER values for device operating at vertical and horizontal polarized modes. For the optimized geometry configuration, the difference between the ER values of two polarization modes, i.e., the ΔER, as small as 0.01 dB/μm is demonstrated and, simultaneously with coupling efficiency above 74%, is obtained for both polarizations at a wavelength of 1.55 μm. The proposed plasmonic-combined modulator has a potential application in guiding and processing of light from a fiber with a random polarization state.

Polarization-Insensitive Surface Plasmon Polarization Electro-Absorption Modulator Based on Epsilon-Near-Zero Indium Tin Oxide

NASA Astrophysics Data System (ADS)

Jin, Lin; Wen, Long; Liang, Li; Chen, Qin; Sun, Yunfei

2018-02-01

CMOS-compatible plasmonic modulators operating at the telecom wavelength are significant for a variety of on-chip applications. Relying on the manipulation of the transverse magnetic (TM) mode excited on the metal-dielectric interface, most of the previous demonstrations are designed to response only for specific polarization state. In this case, it will lead to a high polarization dependent loss, when the polarization-sensitive modulator integrates to a fiber with random polarization state. Herein, we propose a plasmonic modulator utilizing a metal-oxide indium tin oxide (ITO) wrapped around the silicon waveguide and investigate its optical modulation ability for both the vertical and horizontal polarized guiding light by tuning electro-absorption of ITO with the field-induced carrier injection. The electrically biased modulator with electron accumulated at the ITO/oxide interface allows for epsilon-near-zero (ENZ) mode to be excited at the top or lateral portion of the interface depending on the polarization state of the guiding light. Because of the high localized feature of ENZ mode, efficient electro-absorption can be achieved under the "OFF" state of the device, thus leading to large extinction ratio (ER) for both polarizations in our proposed modulator. Further, the polarization-insensitive modulation is realized by properly tailoring the thickness of oxide in two different stacking directions and therefore matching the ER values for device operating at vertical and horizontal polarized modes. For the optimized geometry configuration, the difference between the ER values of two polarization modes, i.e., the ΔER, as small as 0.01 dB/μm is demonstrated and, simultaneously with coupling efficiency above 74%, is obtained for both polarizations at a wavelength of 1.55 μm. The proposed plasmonic-combined modulator has a potential application in guiding and processing of light from a fiber with a random polarization state.

On-line comprehensive two-dimensional normal-phase liquid chromatography×reversed-phase liquid chromatography for preparative isolation of toad venom.

PubMed

Li, Jia-Fu; Fang, Hua; Yan, Xia; Chang, Fang-Rong; Wu, Zhen; Wu, Yun-Long; Qiu, Ying-Kun

2016-07-22

An on-line comprehensive preparative two-dimensional normal-phase liquid chromatography×reversed-phase liquid chromatography (2D NPLC×RPLC) system was constructed with a newly developed vacuum evaporation assisted adsorption (VEAA) interface, allowing fast removal of NPLC solvent in the vacuum condition and successfully solving the solvent incompatibility problem between NPLC and RPLC. The system achieved on-line solvent exchange within the two dimensions and its performance was illustrated by gram-scale isolation of crude extract from the venom of Bufo bufo gargarizans. Within separation time of ∼20h, 19 compounds were obtained with high purity in a single run. With the VEAA interface, the 2D system exhibited apparent advantages in separation efficiency and automation compared with conventional methods, indicating its promising application in the routine separation process for complicated natural products. Copyright © 2016 Elsevier B.V. All rights reserved.

Transport and deposition of the fire biomarker levoglucosan across the tropical North Atlantic Ocean

NASA Astrophysics Data System (ADS)

Schreuder, Laura T.; Hopmans, Ellen C.; Stuut, Jan-Berend W.; Sinninghe Damsté, Jaap S.; Schouten, Stefan

2018-04-01

Biomass burning impacts biogeochemical cycling, vegetation dynamics and climate. However, interactions between fire, climate and vegetation are not well understood and therefore studies have attempted to reconstruct fire and vegetation history under different climatic conditions using sedimentary archives. Here we focus on levoglucosan, a thermal by-product of cellulose generated during biomass burning, and, therefore, a potential fire biomarker in the marine sedimentary archive. However, before levoglucosan can be applied as a biomass burning proxy in marine sediments, there is a need for studies on how levoglucosan is transported to the marine environment, how it is reflecting biomass burning on continents, as well as the fate of levoglucosan in the marine water column and during deposition in marine sediments. Here we present analyses of levoglucosan, using an improved Ultra High Pressure Liquid Chromatography-Electro Spray Ionization/High Resolution Mass Spectrometry (UHPLC-ESI/HRMS) method, in atmospheric particles, in particulate matter settling through the water column and in marine surface sediments on a longitudinal transect crossing the tropical North Atlantic Ocean at 12°N. Levoglucosan was detected in the atmosphere, although in low concentration, possibly due to the sampled particle size, the source area of the aerosols, or the short time interval of sampling by which large burning events may have been missed. In sinking particles in the tropical North Atlantic Ocean we find that levoglucosan deposition is influenced by a mineral ballast effect associated with marine biogenic particles, and that levoglucosan is not transported in association with mineral dust particles. Highest levoglucosan concentrations and seasonal differences in sinking particles were found close to continents and low concentrations and seasonal differences were found in the open ocean. Close to Africa, levoglucosan concentration is higher during winter, reflecting seasonal burning in northwestern Africa. However, close to South America levoglucosan concentrations appear to be affected by riverine transport from the Amazon River. In surface sediments close to South America, levoglucosan concentration is higher than in the middle of the Atlantic Ocean, implying that here the influence from the South American continent is important and perennial. Our study provides evidence that degradation of levoglucosan during settling in the marine water column is not substantial, but is substantial at the sediment-water interface. Nevertheless, levoglucosan was detected in all surface sediments throughout the tropical North Atlantic, indicating its presence in the marine sedimentary record, which reveals the potential for levoglucosan as a biomass burning proxy in marine sediments.

Stability of extemporaneously prepared preservative-free prochlorperazine nasal spray.

PubMed

Yellepeddi, Venkata K

2018-01-01

The stability of an extemporaneously prepared preservative-free prochlorperazine 5-mg/mL nasal spray was evaluated. The preservative-free prochlorperazine nasal spray was prepared by adding 250 mg of prochlorperazine edisylate to 50 mL of citrate buffer in a low-density polyethylene nasal spray bottle. A stability-indicating high-performance liquid chromatography (HPLC) method was developed and validated using the major degradant prochlorperazine sulfoxide and by performing forced-degradation studies. For chemical stability studies, 3 100-μL samples of the preservative-free prochlorperazine from 5 nasal spray bottles stored at room temperature were collected at days 0, 20, 30, 45, and 60 and were assayed in triplicate using the stability-indicating HPLC method. Microbiological testing involved antimicrobial effectiveness testing based on United States Pharmacopeia ( USP ) chapter 51 and quantitative microbiological enumeration of aerobic bacteria, yeasts, and mold based on USP chapter 61. Samples for microbiological testing were collected at days 0, 30, and 60. The stability-indicating HPLC method clearly identified the degradation product prochlorperazine sulfoxide without interference from prochlorperazine. All tested solutions retained over 90% of the initial prochlorperazine concentration for the 60-day study period. There were no detectable changes in color, pH, and viscosity in any sample. There was no growth of bacteria, yeast, and mold for 60 days in all samples tested. An extemporaneously prepared preservative-free nasal spray solution of prochlorperazine edisylate 5 mg/mL was physically, chemically, and microbiologically stable for 60 days when stored at room temperature in low-density polyethylene bottles. Copyright © 2018 by the American Society of Health-System Pharmacists, Inc. All rights reserved.

Thermal Fatigue Behavior of Air-Plasma Sprayed Thermal Barrier Coating with Bond Coat Species in Cyclic Thermal Exposure

PubMed Central

Lu, Zhe; Myoung, Sang-Won; Jung, Yeon-Gil; Balakrishnan, Govindasamy; Lee, Jeongseung; Paik, Ungyu

2013-01-01

The effects of the bond coat species on the delamination or fracture behavior in thermal barrier coatings (TBCs) was investigated using the yclic thermal fatigue and thermal-shock tests. The interface microstructures of each TBC showed a good condition without cracking or delamination after flame thermal fatigue (FTF) for 1429 cycles. The TBC with the bond coat prepared by the air-plasma spray (APS) method showed a good condition at the interface between the top and bond coats after cyclic furnace thermal fatigue (CFTF) for 1429 cycles, whereas the TBCs with the bond coats prepared by the high-velocity oxygen fuel (HVOF) and low-pressure plasma spray (LPPS) methods showed a partial cracking (and/or delamination) and a delamination after 780 cycles, respectively. The TBCs with the bond coats prepared by the APS, HVOF and LPPS methods were fully delaminated (>50%) after 159, 36, and 46 cycles, respectively, during the thermal-shock tests. The TGO thickness in the TBCs was strongly dependent on the both exposure time and temperature difference tested. The hardness values were found to be increased only after the CFTF, and the TBC with the bond coat prepared by the APS showed the highest adhesive strength before and after the FTF. PMID:28811441

The Influence of the Coating Deposition Process on the Interdiffusion Behavior Between Nickel-Based Superalloys and MCrAlY Bond Coats

NASA Astrophysics Data System (ADS)

Elsaß, M.; Frommherz, M.; Oechsner, M.

2018-02-01

In this work, interdiffusion between two nickel-based superalloys and two MCrAlY bond coats is investigated. The MCrAlY bond coats were applied using two different spraying processes, high velocity oxygen fuel spraying (HVOF) and low-pressure plasma spraying. Of primary interest is the evolution of Kirkendall porosity, which can form at the interface between substrate and bond coat and depends largely on the chemical compositions of the coating and substrate. Experimental evidence further suggested that the formation of Kirkendall porosity depends on the coating deposition process. Formation of porosity at the interface causes a degradation of the bonding strength between substrate and coating. After coating deposition, the samples were annealed at 1050 °C for up to 2000 h. Microstructural and compositional analyses were performed to determine and evaluate the Kirkendall porosity. The results reveal a strong influence of both the coating deposition process and the chemical compositions. The amount of Kirkendall porosity formed, as well as the location of appearance, is largely influenced by the coating deposition process. In general, samples with bond coats applied by means of HVOF show accelerated element diffusion. It is hypothesized that recrystallization of the substrate material is a main root cause for these observations.

Infrared Thermography as a Non-destructive Testing Solution for Thermal Spray Metal Coatings

NASA Astrophysics Data System (ADS)

Santangelo, Paolo E.; Allesina, Giulio; Bolelli, Giovanni; Lusvarghi, Luca; Matikainen, Ville; Vuoristo, Petri

2017-12-01

In this work, an infrared (IR) thermographic procedure was evaluated as a non-destructive testing tool to detect damage in thermal spray metallic coatings. As model systems, polished HVOF- and HVAF-sprayed Fe-based layers deposited onto steel plates were employed. Damage by external-object impingement was simulated through a cyclic impact-test apparatus, which induced circumferential and radial cracks across all model systems, and interface cracks of different sizes in distinct samples. Damaged and undamaged plates were bulk-heated to above 100 °C using an IR lamp; their free-convection cooling was then recorded by an IR thermocamera. The intentionally induced defects were hardly detectable in IR thermograms, due to IR reflection and artificial "hot" spots induced by residuals of transfer material from the impacting counterbody. As a micrometer-thin layer of black paint was applied, surface emissivity got homogenized and any artifacts were effectively suppressed, so that failed coating areas clearly showed up as "cold spots." This effect was more apparent when large interface cracks occurred. Finite-element modeling proved the physical significance of the IR-thermography approach, showing that failed coating areas are cooled by surrounding air faster than they are heated by conduction from the hot substrate, which is due to the insulating effect of cracks.

Efficient control system for low-concentration inorganic gases from a process vent stream: application of surfactants in spray and packed columns.

PubMed

Chein, Hungmin; Aggarwal, Shankar G; Wu, Hsin-Hsien

2004-11-01

Control of low-concentration pollutants from a semiconductor process vent stream using a wet-scrubbing technique is a challenging task to meet Taiwan environmental emission standards. An efficient wet-scrubber is designed on a pilot scale and tested to control low concentration acid and base waste-gas emission. The scrubber system consisted of two columns, i.e., a fine spray column [cutoff diameter (based on volume), Dv(50) = 15.63 microm; Sauter mean diameter (SMD) = 7.62 microm], which is especially efficient for NH3 removal as the pH of the spraying liquid is approximately 7 followed by a packed column with a scrubbing liquid pH approximately 9.0 mainly for acids removal. It is observed that use of the surfactants in low concentration about 10(-4) M and 10(-7) M in the spray liquid and in the scrubbing liquid, respectively, remarkably enhances the removal efficiency of the system. A traditional packed column (without the spray column and the surfactant) showed that the removal efficiencies of NH3, HF, and HCl for the inlet concentration range 0.2 to 3 ppm were (n = 5) 22.6+/-3.4%, 43.4+/-5.5%, and 40.4+/-7.4%, respectively. The overall efficiencies of the proposed system (the spray column and the packed column) in the presence of the surfactant in the spray liquid and in the scrubbing liquid forthese three species were found to increase significantly (n = 5) from 60.3+/-3.6 to 82.8+/-6.8%, 59.1+/-2.7 to 83.4+/-4.2%, and 56.2+/-7.3 to 81.0+/-6.7%, respectively. In this work, development of charge on the gas-liquid interface due to the surfactants has been measured and discussed. It is concluded that the presence of charge on the gas-liquid interface is the responsible factor for enhancement of the removal efficiency (mass-transfer in liquid phase). The effects of the type of surfactants, their chain length, concentration in liquid, etc. on the removal efficiency are discussed. Since the pilot tests were performed under the operating conditions similar to most of the wet-scrubbers operated in semiconductors manufacturing facilities for inorganic pollutants, this study can be applied to modify the existing wet-scrubbers to enhance the removal efficiencies, especially for low-concentration pollutants.

Numerical modeling of materials processes with fluid-fluid interfaces

NASA Astrophysics Data System (ADS)

Yanke, Jeffrey Michael

A numerical model has been developed to study material processes that depend on the interaction between fluids with a large discontinuity in thermophysical properties. A base model capable of solving equations of mass, momentum, energy conservation, and solidification has been altered to enable tracking of the interface between two immiscible fluids and correctly predict the interface deformation using a volume of fluid (VOF) method. Two materials processes investigated using this technique are Electroslag Remelting (ESR) and plasma spray deposition. ESR is a secondary melting technique that passes an AC current through an electrically resistive slag to provide the heat necessary to melt the alloy. The simulation tracks the interface between the slag and metal. The model was validated against industrial scale ESR ingots and was able to predict trends in melt rate, sump depth, macrosegregation, and liquid sump depth. In order to better understand the underlying physics of the process, several constant current ESR runs simulated the effects of freezing slag in the model. Including the solidifying slag in the imulations was found to have an effect on the melt rate and sump shape but there is too much uncertainty in ESR slag property data at this time for quantitative predictions. The second process investigated in this work is the deposition of ceramic coatings via plasma spray deposition. In plasma spray deposition, powderized coating material is injected into a plasma that melts and carries the powder towards the substrate were it impacts, flattening out and freezing. The impacting droplets pile up to form a porous coating. The model is used to simulate this rain of liquid ceramic particles impacting the substrate and forming a coating. Trends in local solidification time and porosity are calculated for various particle sizes and velocities. The predictions of decreasing porosity with increasing particle velocity matches previous experimental results. Also, a preliminary study was conducted to investigate the effects of substrate surface defects and droplet impact angle on the propensity to form columnar porosity.

Interface bonding of NiCrAlY coating on laser modified H13 tool steel surface

NASA Astrophysics Data System (ADS)

Reza, M. S.; Aqida, S. N.; Ismail, I.

2016-06-01

Bonding strength of thermal spray coatings depends on the interfacial adhesion between bond coat and substrate material. In this paper, NiCrAlY (Ni-164/211 Ni22 %Cr10 %Al1.0 %Y) coatings were developed on laser modified H13 tool steel surface using atmospheric plasma spray (APS). Different laser peak power, P p, and duty cycle, DC, were investigated in order to improve the mechanical properties of H13 tool steel surface. The APS spraying parameters setting for coatings were set constant. The coating microstructure near the interface was analyzed using IM7000 inverted optical microscope. Interface bonding of NiCrAlY was investigated by interfacial indentation test (IIT) method using MMT-X7 Matsuzawa Hardness Tester Machine with Vickers indenter. Diffusion of atoms along NiCrAlY coating, laser modified and substrate layers was investigated by energy-dispersive X-ray spectroscopy (EDXS) using Hitachi Tabletop Microscope TM3030 Plus. Based on IIT method results, average interfacial toughness, K avg, for reference sample was 2.15 MPa m1/2 compared to sample L1 range of K avg from 6.02 to 6.96 MPa m1/2 and sample L2 range of K avg from 2.47 to 3.46 MPa m1/2. Hence, according to K avg, sample L1 has the highest interface bonding and is being laser modified at lower laser peak power, P p, and higher duty cycle, DC, prior to coating. The EDXS analysis indicated the presence of Fe in the NiCrAlY coating layer and increased Ni and Cr composition in the laser modified layer. Atomic diffusion occurred in both coating and laser modified layers involved in Fe, Ni and Cr elements. These findings introduce enhancement of coating system by substrate surface modification to allow atomic diffusion.

CFD Modeling of the Multipurpose Hydrogen Test Bed (MHTB) Self-Pressurization and Spray Bar Mixing Experiments in Normal Gravity: Effect of the Accommodation Coefficient on the Tank Pressure

NASA Technical Reports Server (NTRS)

Kartuzova, Olga; Kassemi, Mohammad

2015-01-01

A CFD model for simulating the self-pressurization of a large scale liquid hydrogen storage tank is utilized in this paper to model the MHTB self-pressurization experiment. The kinetics-based Schrage equation is used to account for the evaporative and condensi ng interfacial mass flows in this model. The effect of the accommodation coefficient for calculating the interfacial mass transfer rate on the tank pressure during tank selfpressurization is studied. The values of the accommodation coefficient which were considered in this study vary from 1.0e-3 to 1.0e-1 for the explicit VOF model and from 1.0e-4 to 1.0e-3 for the implicit VOF model. The ullage pressure evolutions are compared against experimental data. A CFD model for controlling pressure in cryogenic storage tanks by spraying cold liquid into the ullage is also presented. The Euler-Lagrange approach is utilized for tracking the spray droplets and for modeling the interaction between the droplets and the continuous phase (ullage). The spray model is coupled with the VOF model by performing particle tracking in the ullage, removing particles from the ullage when they reach the interface, and then adding their contributions to the liquid. Droplet-ullage heat and mass transfer are modeled. The flow, temperature, and interfacial mass flux, as well as droplets trajectories, size distribution and temperatures predicted by the model are presented. The ul lage pressure and vapor temperature evolutions are compared with experimental data obtained from the MHTB spray bar mixing experiment. The effect of the accommodation coefficient for calculating the interfacial and droplet mass transfer rates on the tank pressure during mixing of the vapor using spray is studied. The values used for the accommodation coefficient at the interface vary from 1.0e-5 to 1.0e-2. The droplet accommodation coefficient values vary from 2.0e-6 to 1.0e-4.

On the Interplay Between Adhesion Strength and Tensile Properties of Thermal Spray Coated Laminates—Part II: Low-Velocity Thermal Spray Coatings

NASA Astrophysics Data System (ADS)

Luo, Xiaotao; Smith, Gregory M.; Sampath, Sanjay

2018-02-01

In this two-part study, uniaxial tensile testing was used to evaluate coating/substrate bonding and compared with traditional ASTM C633 bond pull test results for thermal spray (TS) coated steel laminates. In Part I, the rationale, methodology, and applicability of the test to high-velocity TS coatings were demonstrated. In this Part II, the method was investigated for low-velocity TS processes (air plasma spray and arc spray) on equivalent materials. Ni and Ni-5wt.%Al coatings were deposited on steel substrates with three different roughness levels and tested using both uniaxial tensile and ASTM C633 methods. The results indicate the uniaxial tensile approach provides useful information about the nature of the coating/substrate bonding and goes beyond the traditional bond pull test in providing insightful information on the load sharing processes across the interface. Additionally, this proposed methodology alleviates some of the longstanding shortcomings and potentially reduces error associated with the traditional ASTM C633 test. The mechanisms governing the load transfer between the substrate and the coating were investigated, and the influence of Al in the coating material evaluated.

Characterization of commercially cold sprayed copper coatings and determination of the effects of impacting copper powder velocities

NASA Astrophysics Data System (ADS)

Jakupi, P.; Keech, P. G.; Barker, I.; Ramamurthy, S.; Jacklin, R. L.; Shoesmith, D. W.; Moser, D. E.

2015-11-01

Copper coated steel containers are being developed for the disposal of high level nuclear waste using processes such as cold spray and electrodeposition. Electron Back-Scatter Diffraction has been used to determine the microstructural properties and the quality of the steel-copper coating interface. The influence of the nature of the cold-spray carrier gas as well as its temperature and pressure (velocity) on the coating's plastic strain and recrystallization behaviour have been investigated, and one commercially-produced electrodeposited coating characterized. The quality of the coatings was assessed using the coincident site lattice model to analyse the properties of the grain boundaries. For cold spray coatings the grain size and number of coincident site lattice grain boundaries increased, and plastic strain decreased, with carrier gas velocity. In all cases annealing improved the quality of the coatings by increasing texture and coincidence site-lattices, but also increased the number of physical voids, especially when a low temperature cold spray carrier gas was used. Comparatively, the average grain size and number of coincident site-lattices was considerably larger for the strongly textured electrodeposited coating. Tensile testing showed the electrodeposited coating was much more strongly adherent to the steel substrate.

Deflagration-to-detonation characteristics of a laser exploding bridge detonator

NASA Astrophysics Data System (ADS)

Welle, E. J.; Fleming, K. J.; Marley, S. K.

2006-08-01

Evaluation of laser initiated explosive trains has been an area of extreme interest due to the safety benefits of these systems relative to traditional electro-explosive devices. A particularly important difference is these devices are inherently less electro-static discharge (ESD) sensitive relative to traditional explosive devices due to the isolation of electrical power and associated materials from the explosive interface. This paper will report work conducted at Sandia National Laboratories' Explosive Components Facility, which evaluated the initiation and deflagration-to-detonation characteristics of a Laser Driven Exploding Bridgewire detonator. This paper will report and discuss characteristics of Laser Exploding Bridgewire devices loaded with hexanitrohexaazaisowurtzitane (CL-20) and tetraammine-cis-bis-(5-nitro-2H-tetrazolato-N2) cobalt (III) perchlorate (BNCP).

Linear or Rotary Actuator Using Electromagnetic Driven Hammer as Prime Mover

NASA Technical Reports Server (NTRS)

McMahan, Bert K. (Inventor); Sesler, Joshua J. (Inventor); Paine, Matthew T. (Inventor); McMahan, Mark C. (Inventor); Paine, Jeffrey S. N. (Inventor); Smith, Byron F. (Inventor)

2018-01-01

We claim a hammer driven actuator that uses the fast-motion, low-force characteristics of an electro-magnetic or similar prime mover to develop kinetic energy that can be transformed via a friction interface to produce a higher-force, lower-speed linear or rotary actuator by using a hammering process to produce a series of individual steps. Such a system can be implemented using a voice-coil, electro-mechanical solenoid or similar prime mover. Where a typical actuator provides limited range of motion or low force, the range of motion of a linear or rotary impact driven motor can be configured to provide large displacements which are not limited by the characteristic dimensions of the prime mover.

Shock tube studies of thermal radiation of diesel-spray combustion under a range of spray conditions

NASA Astrophysics Data System (ADS)

Tsuboi, T.; Kurihara, Y.; Takasaki, M.; Katoh, R.; Ishii, K.

2007-05-01

A tailored interface shock tube and an over-tailored interface shock tube were used to measure the thermal energy radiated during diesel-spray combustion of light oil, α-methylnaphthalene and cetane by changing the injection pressure. The ignition delay of methanol and the thermal radiation were also measured. Experiments were performed in a steel shock tube with a 7 m low-pressure section filled with air and a 6 m high-pressure section. Pre-compressed fuel was injected through a throttle nozzle into air behind a reflected shock wave. Monochromatic emissive power and the power emitted across all infrared wavelengths were measured with IR-detectors set along the central axis of the tube. Time-dependent radii where soot particles radiated were also determined, and the results were as follows. For diesel spray combustion with high injection pressures (from 10 to 80 MPa), the thermal radiation energy of light oil per injection increased with injection pressure from 10 to 30 MPa. The energy was about 2% of the heat of combustion of light oil at P inj = about 30 MPa. At injection pressure above 30 MPa the thermal radiation decreased with increasing injection pressure. This profile agreed well with the combustion duration, the flame length, the maximum amount of soot in the flame, the time-integrated soot volume and the time-integrated flame volume. The ignition delay of light oil was observed to decrease monotonically with increasing fuel injection pressure. For diesel spray combustion of methanol, the thermal radiation including that due to the gas phase was 1% of the combustion heat at maximum, and usually lower than 1%. The thermal radiation due to soot was lower than 0.05% of the combustion heat. The ignition delays were larger (about 50%) than those of light oil. However, these differences were within experimental error.

The Effect of Deposition Conditions on Adhesion Strength of Ti and Ti6Al4V Cold Spray Splats

NASA Astrophysics Data System (ADS)

Goldbaum, Dina; Shockley, J. Michael; Chromik, Richard R.; Rezaeian, Ahmad; Yue, Stephen; Legoux, Jean-Gabriel; Irissou, Eric

2012-03-01

Cold spray is a complex process where many parameters have to be considered in order to achieve optimized material deposition and properties. In the cold spray process, deposition velocity influences the degree of material deformation and material adhesion. While most materials can be easily deposited at relatively low deposition velocity (<700 m/s), this is not the case for high yield strength materials like Ti and its alloys. In the present study, we evaluate the effects of deposition velocity, powder size, particle position in the gas jet, gas temperature, and substrate temperature on the adhesion strength of cold spayed Ti and Ti6Al4V splats. A micromechanical test technique was used to shear individual splats of Ti or Ti6Al4V and measure their adhesion strength. The splats were deposited onto Ti or Ti6Al4V substrates over a range of deposition conditions with either nitrogen or helium as the propelling gas. The splat adhesion testing coupled with microstructural characterization was used to define the strength, the type and the continuity of the bonded interface between splat and substrate material. The results demonstrated that optimization of spray conditions makes it possible to obtain splats with continuous bonding along the splat/substrate interface and measured adhesion strengths approaching the shear strength of bulk material. The parameters shown to improve the splat adhesion included the increase of the splat deposition velocity well above the critical deposition velocity of the tested material, increase in the temperature of both powder and the substrate material, decrease in the powder size, and optimization of the flow dynamics for the cold spray gun nozzle. Through comparisons to the literature, the adhesion strength of Ti splats measured with the splat adhesion technique correlated well with the cohesion strength of Ti coatings deposited under similar conditions and measured with tubular coating tensile (TCT) test.

COLLABORATIVE RESEARCH AND DEVELOPMENT (CR&D) Delivery Order 0068: Anti-fretting Coatings Research and Development

DTIC Science & Technology

2008-02-01

reduction in fatigue strength [10]. One common mitigation strategy to the fretting wear/fatigue problem in titanium alloy compressor blades is to...inter-metallic fretting wear between Ti6Al4V ( Titanium , 6% Aluminum, 4% Vanadium) and cold-sprayed, commercially pure nickel coatings. The results...fretting in an aircraft turbine engine is in the compressor section at the blade /disk interface. The blade /disk interface, also known as the

A Review of Organic and Inorganic Biomaterials for Neural Interfaces

PubMed Central

Fattahi, Pouria; Yang, Guang; Kim, Gloria

2015-01-01

Recent advances in nanotechnology have generated wide interest in applying nanomaterials for neural prostheses. An ideal neural interface should create seamless integration into the nervous system and performs reliably for long periods of time. As a result, many nanoscale materials not originally developed for neural interfaces become attractive candidates to detect neural signals and stimulate neurons. In this comprehensive review, an overview of state-of-the-art microelectrode technologies provided first, with focus on the material properties of these microdevices. The advancements in electro active nanomaterials are then reviewed, including conducting polymers, carbon nanotubes, graphene, silicon nanowires, and hybrid organic-inorganic nanomaterials, for neural recording, stimulation, and growth. Finally, technical and scientific challenges are discussed regarding biocompatibility, mechanical mismatch, and electrical properties faced by these nanomaterials for the development of long-lasting functional neural interfaces. PMID:24677434

A review of organic and inorganic biomaterials for neural interfaces.

PubMed

Fattahi, Pouria; Yang, Guang; Kim, Gloria; Abidian, Mohammad Reza

2014-03-26

Recent advances in nanotechnology have generated wide interest in applying nanomaterials for neural prostheses. An ideal neural interface should create seamless integration into the nervous system and performs reliably for long periods of time. As a result, many nanoscale materials not originally developed for neural interfaces become attractive candidates to detect neural signals and stimulate neurons. In this comprehensive review, an overview of state-of-the-art microelectrode technologies provided fi rst, with focus on the material properties of these microdevices. The advancements in electro active nanomaterials are then reviewed, including conducting polymers, carbon nanotubes, graphene, silicon nanowires, and hybrid organic-inorganic nanomaterials, for neural recording, stimulation, and growth. Finally, technical and scientific challenges are discussed regarding biocompatibility, mechanical mismatch, and electrical properties faced by these nanomaterials for the development of long-lasting functional neural interfaces.

Humectants to augment current from metallized zinc cathodic protection systems on concrete : final report.

DOT National Transportation Integrated Search

2002-12-01

Cathodic protection (CP) systems using thermal-sprayed zinc anodes are employed to mitigate the corrosion process in reinforced concrete structures. However, the performance of the anodes is improved by moisture at the anode-concrete interface. Resea...

Extraction and Separation of Active Ingredients in Schisandra chinensis (Turcz.) Baill and the Study of their Antifungal Effects

PubMed Central

Liu, Jun; Zhang, Jie; Guo, Wei; Xiao, Weilie; Yao, Yuncong

2016-01-01

Schisandra chinensis extracts (SEs) have traditionally been used as an oriental medicine for the treatment of various human diseases, however, their further application in the biocontrol of plant disease remains poorly understood. This study was conducted to develop eco-friendly botanical pesticides from extracts of S. chinensis and assess whether they could play a key role in plant disease defense. Concentrated active fractions (SE-I, SE-II, and SE-III) were obtained from S. chinensis via specific extraction and separation. Then, lignan-like substances, such as Schisanhenol B, were detected via High-Performance Liquid Chromatography-ElectroSpray Ionization-Mass Spectrometry (HPLC-ESI-MS) analyses of the active fractions. Moreover, the results from biological tests on colony growth inhibition and spore germination indicated that SE-I, SE-II, and SE-III could inhibit hyphal growth and spore generation of three important plant pathogenic fungi (Monilinia fructicola, Fusarium oxysporum, and Botryosphaeria dothidea). The study of the mechanisms of resistant fungi revealed that the oxidation resistance system, including reactive oxygen species (ROS), malondialdehyde (MDA), catalase (CAT), and superoxide dismutase (SOD), was activated. The expression of genes related to defense, such as pathogenesis-related protein (PR4), α-farnesene synthase (AFS), polyphenol oxidase (PPO), and phenylalanine ammonia lyase (PAL) were shown to be up-regulated after treatment with SEs, which suggested an increase in apple immunity and that fruits were induced to effectively defend against the infection of pathogenic fungi (B. dothidea). This study revealed that SEs and their lignans represent promising resources for the development of safe, effective, and multi-targeted agents against pathogenic fungi. PMID:27152614

Anxiolytic- and antidepressant-like effects of an aqueous extract of Tanacetum parthenium L. Schultz-Bip (Asteraceae) in mice.

PubMed

Cárdenas, Jorge; Reyes-Pérez, Valeria; Hernández-Navarro, María Dolores; Dorantes-Barrón, Ana María; Almazán, Salvador; Estrada-Reyes, Rosa

2017-03-22

Tanacetum parthenium L. Schultz-Bip (Asteraceae) is widely used worldwide in traditional medicine for the treatment of convulsions and culture-bound syndromes such as susto (fear). The aim of this work was to evaluate the anxiolytic- and antidepressant-like effects of an aqueous extract of T. parthenium in behavioral paradigms in mice. The effects of T. parthenium were compared with those produced by anxiolytic and antidepressant drugs. We carried out the chemical characterization of the main constituents of T. parthenium. The involvement with the GABAergic and serotoninergic neurotransmitter systems were explored be means of synergic and antagonist experiments. The anxiolytic-like effect was evaluated using the Burying Behavior Test (BBT) and the Elevated Plus-Maze Test (PMT). The antidepressant-like effect was evaluated in the Forced Swimming Test (FST), and ambulatory activity was assessed in the Open Field Test (OFT). Employing the behavioral tests, synergism and antagonism experiments with Alprazolam, Muscimol, and Picrotoxin were carried out in the PMT. In a series of independent experiments, concomitant administration of T. parthenium and Alprazolam, Fluoxetine, or p-chlorophenylalanine were conducted in the FST. For chemical characterization, High-Performance Liquid Chromatography-Electro Spray Ionization-Mass Spectrometry (HPLC-ESI-MS) analysis was performed. T. parthenium exerts clear anxiolytic- and antidepressant-like effects in mice, without affecting the ambulatory activity of the experimental subjects. Anxiolytic- and antidepressant-like T. parthenium effects result, at least part from the involvement of the GABAergic system. Our results support the use of Tanacetum parthenium in traditional medicine and suggest its therapeutic potential in the comorbid anxiety and depression. Copyright © 2017 Elsevier Ireland Ltd. All rights reserved.

Development of "one-pot" method for multi-class compounds in porcine formula feed by multi-function impurity adsorption cleaning followed ultra-performance liquid chromatography-tandem mass spectrometry detection.

PubMed

Wang, Peilong; Wang, Xiao; Zhang, Wei; Su, Xiaoou

2014-02-01

A novel and efficient determination method for multi-class compounds including β-agonists, sedatives, nitro-imidazoles and aflatoxins in porcine formula feed based on a fast "one-pot" extraction/multifunction impurity adsorption (MFIA) clean-up procedure has been developed. 23 target analytes belonging to four different class compounds could be determined simultaneously in a single run. Conditions for "one-pot" extraction were studied in detail. Under the optimized conditions, the multi-class compounds in porcine formula feed samples were extracted and purified with methanol contained ammonia and absorbents by one step. The compounds in extracts were purified by using multi types of absorbent based on MFIA in one pot. The multi-walled carbon nanotubes were employed to improved clean-up efficiency. Shield BEH C18 column was used to separate 23 target analytes, followed by tandem mass spectrometry (MS/MS) detection using an electro-spray ionization source in positive mode. Recovery studies were done at three fortification levels. Overall average recoveries of target compounds in porcine formula feed at each levels were >51.6% based on matrix fortified calibration with coefficients of variation from 2.7% to 13.2% (n=6). The limit of determination (LOD) of these compounds in porcine formula feed sample matrix was <5.0 μg/kg. This method was successfully applied in screening and confirmation of target drugs in >30 porcine formula feed samples. It was demonstrated that the integration of the MFIA protocol with the MS/MS instrument could serve as a valuable strategy for rapid screening and reliable confirmatory analysis of multi-class compounds in real samples. Copyright © 2013 Elsevier B.V. All rights reserved.

Apparatus and method for performing microfluidic manipulations for chemical analysis

DOEpatents

Ramsey, J. Michael

1999-01-01

A microchip apparatus and method provide fluidic manipulations for a variety of applications, including sample injection for microchip liquid chromatography. The microchip is fabricated using standard photolithographic procedures and chemical wet etching, with the substrate and cover plate joined using direct bonding. Capillary electrophoresis is performed in channels formed in the substrate. Injections are made by electro-osmotically pumping sample through the injection channel that crosses the separation channel, followed by a switching of the potentials to force a plug into the separation channel.

Apparatus and method for performing microfluidic manipulations for chemical analysis

DOEpatents

Ramsey, J. Michael

2002-01-01

A microchip apparatus and method provide fluidic manipulations for a variety of applications, including sample injection for microchip liquid chromatography. The microchip is fabricated using standard photolitographic procedures and chemical wet etching, with the substrate and cover plate joined using direct bonding. Capillary electrophoresis is performed in channels formed in the substrate. Injections are made by electro-osmotically pumping sample through the injection channel that crosses the separation channel, followed by a switching of the potentials to force a plug into the separation channel.

Highly informative multiclass profiling of lipids by ultra-high performance liquid chromatography - Low resolution (quadrupole) mass spectrometry by using electrospray ionization and atmospheric pressure chemical ionization interfaces.

PubMed

Beccaria, Marco; Inferrera, Veronica; Rigano, Francesca; Gorynski, Krzysztof; Purcaro, Giorgia; Pawliszyn, Janusz; Dugo, Paola; Mondello, Luigi

2017-08-04

A simple, fast, and versatile method, using an ultra-high performance liquid chromatography system coupled with a low resolution (single quadrupole) mass spectrometer was optimized to perform multiclass lipid profiling of human plasma. Particular attention was made to develop a method suitable for both electrospray ionization and atmospheric pressure chemical ionization interfaces (sequentially in positive- and negative-ion mode), without any modification of the chromatographic conditions (mobile phase, flow-rate, gradient, etc.). Emphasis was given to the extrapolation of the structural information based on the fragmentation pattern obtained using atmospheric pressure chemical ionization interface, under each different ionization condition, highlighting the complementary information obtained using the electrospray ionization interface, of support for related molecule ions identification. Furthermore, mass spectra of phosphatidylserine and phosphatidylinositol obtained using the atmospheric pressure chemical ionization interface are reported and discussed for the first time. Copyright © 2017 Elsevier B.V. All rights reserved.

Application of cyclodextrins in antibody microparticles: potentials for antibody protection in spray drying.

PubMed

Ramezani, Vahid; Vatanara, Alireza; Seyedabadi, Mohammad; Nabi Meibodi, Mohsen; Fanaei, Hamed

2017-07-01

Dry powder formulations are extensively used to improve the stability of antibodies. Spray drying is one of important methods for protein drying. This study investigated the effects of trehalose, hydroxypropyl beta cyclodextrin (HPBCD) and beta cyclodextrin (BCD) on the stability and particle properties of spray-dried IgG. D-optimal design was employed for both experimental design and analysis and optimization of the variables. The size and aerodynamic behavior of particles were determined using laser light scattering and glass twin impinger, respectively. In addition, stability, ratio of beta sheets and morphology of antibody were analyzed using size exclusion chromatography, IR spectroscopy and electron microscopy, respectively. Particle properties and antibody stability were significantly improved in the presence of HPBCD. In addition, particle aerodynamic behavior, in terms of fine-particle fraction (FPF), enhanced up to 52.23%. Furthermore, antibody was better preserved not only during spray drying, but also during long-term storage. In contrast, application of BCD resulted in the formation of larger particles. Although trehalose caused inappropriate aerodynamic property, it efficiently decreased antibody aggregation. HPBCD is an efficient excipient for the development of inhalable protein formulations. In this regard, optimal particle property and antibody stability was obtained with proper combination of cyclodextrins and simple sugars, such as trehalose.

Research topics on EO systems for maritime platforms

NASA Astrophysics Data System (ADS)

Dijk, Judith; Bijl, Piet; van den Broek, Sebastiaan P.; van Eijk, Alenxander M. J.

2014-10-01

Our world is constantly changing, and this has its effect on worldwide military operations. For example, there is a change from conventional warfare into a domain that contains asymmetric threats as well. The availability of high-quality imaging information from Electro-Optical (EO) sensors is of high importance, for instance for timely detection and identification of small threatening vessels in an environment with a large amount of neutral vessels. Furthermore, Rules of Engagement often require a visual identification before action is allowed. The challenge in these operations is to detect, classify and identify a target at a reasonable range, while avoiding too many false alarms or missed detections. Current sensor technology is not able to cope with the performance requirements under all circumstances. For example, environmental conditions can reduce the sensor range in such a way that the operational task becomes challenging or even impossible. Further, limitations in automatic detection algorithms occur, e.g. due to the effects of sun glints and spray which are not yet well-modelled in the detection filters. For these reasons, Tactical Decision Aids will become an important factor in future operations to select the best moment to act. In this paper, we describe current research within The Netherlands on this topic. The Defence Research and Development Programme "Multifunctional Electro-Optical Sensor Suite (MEOSS)" aims at the development of knowledge necessary for optimal employment of Electro-Optical systems on board of current and future ships of the Royal Netherlands Navy, in order to carry out present and future maritime operations in various environments and weather conditions.

Macro controlling of copper oxide deposition processes and spray mode by using home-made fully computerized spray pyrolysis system

NASA Astrophysics Data System (ADS)

Essa, Mohammed Sh.; Chiad, Bahaa T.; Shafeeq, Omer Sh.

2017-09-01

Thin Films of Copper Oxide (CuO) absorption layer have been deposited using home-made Fully Computerized Spray Pyrolysis Deposition system FCSPD on glass substrates, at the nozzle to substrate distance equal to 20,35 cm, and computerized spray mode (continues spray, macro-control spray). The substrate temperature has been kept at 450 °c with the optional user can enter temperature tolerance values ± 5 °C. Also that fixed molar concentration of 0.1 M, and 2D platform speed or deposition platform speed of 4mm/s. more than 1000 instruction program code, and specific design of graphical user interface GUI to fully control the deposition process and real-time monitoring and controlling the deposition temperature at every 200 ms. The changing in the temperature has been recorded during deposition processes, in addition to all deposition parameters. The films have been characterized to evaluate the thermal distribution over the X, Y movable hot plate, the structure and optical energy gap, thermal and temperature distribution exhibited a good and uniform distribution over 20 cm2 hot plate area, X-ray diffraction (XRD) measurement revealed that the films are polycrystalline in nature and can be assigned to monoclinic CuO structure. Optical band gap varies from 1.5-1.66 eV depending on deposition parameter.

Effects of Traverse Scanning Speed of Spray Nozzle on the Microstructure and Mechanical Properties of Cold-Sprayed Ti6Al4V Coatings

NASA Astrophysics Data System (ADS)

Tan, Adrian Wei-Yee; Sun, Wen; Phang, Yun Peng; Dai, Minghui; Marinescu, Iulian; Dong, Zhili; Liu, Erjia

2017-10-01

Cold spray has the potential to restore damaged aerospace components made from titanium alloy, Ti6Al4V at low temperature (200-400 °C). Traverse scanning speed during deposition is one of the key factors that affect the quality of the Ti6Al4V coatings as it influences the thermal build-up and coating thickness per pass. As there are fewer reported studies on this, this work investigated the effects of different traverse scanning speeds (100, 300 and 500 mm/s) of cold spray nozzle on the microstructure and mechanical properties of cold-sprayed Ti6Al4V coatings. The cross-sectional analysis showed coating porosities reduces with slower traverse speed, from 3.2 to 0.5%. In addition, the microhardness of the coatings increased from about 361-385 HV due to strain hardening. However, the adhesion strength of the coatings to the substrates significantly decreased with reduced traverse speed from about 60 MPa (glue failure) at 500 mm/s to 2.5 MPa (interface failure) at 100 mm/s. Therefore, this study revealed that the control of heat build-up and thickness per pass during the cold spray deposition of the Ti6Al4V coatings is crucial to attain the desirable properties of the coatings.

A developed determination of midazolam and 1'-hydroxymidazolam in plasma by liquid chromatography-mass spectrometry: application of human pharmacokinetic study for measurement of CYP3A activity.

PubMed

Shimizu, Mikiko; Uno, Tsukasa; Tamura, Hiro-omi; Kanazawa, Hideko; Murakami, Isao; Sugawara, Kazunobu; Tateishi, Tomonori

2007-03-01

This paper describes sensitive and reliable determination of midazolam (MDZ) and its major metabolite 1'-hydroxymidazolam (1-OHMDZ) in human plasma by liquid chromatography-mass spectrometry (LC-MS) with a sonic spray ionization (SSI) interface. MDZ, 1-OHMDZ and diazepam as an internal standard were extracted from 1ml of alkalinized plasma using n-hexane-chloroform (70:30, v/v). The extract was injected into an analytical column (YMC-Pak Pro C(18), 50mmx2.0mmi.d.). The mobile phase for separation consisted of 10mM ammonium acetate and methanol (50:50, v/v) and was delivered at a flow-rate of 0.2ml/min. The drift voltage was 100V. The sampling aperture was heated at 120 degrees C and the shield temperature was 260 degrees C. The total time for chromatographic separation was less than 16min. The validated concentration ranges of this method were 0.25-50ng/ml for both MDZ and 1-OHMDZ. Mean recoveries were 93.6% for MDZ and 86.6% for 1-OHMDZ. Intra- and inter-day coefficient variations were less than 6.5 and 5.5% for MDZ, and 6.1 and 5.7% for 1-OHMDZ at 0.3, 4, 20 and 40ng/ml. The limits of quantification were 0.25ng/ml for both MDZ and 1-OHMDZ. This method was sensitive and reliable enough for pharmacokinetic studies on healthy volunteers, and was applied for the measurement of CYP3A activity in humans after an intravenous (1mg) and a single-oral administration (2mg) of subtherapeutic MDZ dose.

Plasma and cold sprayed aluminum carbon nanotube composites: Quantification of nanotube distribution and multi-scale mechanical properties

NASA Astrophysics Data System (ADS)

Bakshi, Srinivasa Rao

Carbon nanotubes (CNT) could serve as potential reinforcement for metal matrix composites for improved mechanical properties. However dispersion of carbon nanotubes (CNT) in the matrix has been a longstanding problem, since they tend to form clusters to minimize their surface area. The aim of this study was to use plasma and cold spraying techniques to synthesize CNT reinforced aluminum composite with improved dispersion and to quantify the degree of CNT dispersion as it influences the mechanical properties. Novel method of spray drying was used to disperse CNTs in Al-12 wt.% Si prealloyed powder, which was used as feedstock for plasma and cold spraying. A new method for quantification of CNT distribution was developed. Two parameters for CNT dispersion quantification, namely Dispersion parameter (DP) and Clustering Parameter (CP) have been proposed based on the image analysis and distance between the centers of CNTs. Nanomechanical properties were correlated with the dispersion of CNTs in the microstructure. Coating microstructure evolution has been discussed in terms of splat formation, deformation and damage of CNTs and CNT/matrix interface. Effect of Si and CNT content on the reaction at CNT/matrix interface was thermodynamically and kinetically studied. A pseudo phase diagram was computed which predicts the interfacial carbide for reaction between CNT and Al-Si alloy at processing temperature. Kinetic aspects showed that Al4C3 forms with Al-12 wt.% Si alloy while SiC forms with Al-23wt.% Si alloy. Mechanical properties at nano, micro and macro-scale were evaluated using nanoindentation and nanoscratch, microindentation and bulk tensile testing respectively. Nano and micro-scale mechanical properties (elastic modulus, hardness and yield strength) displayed improvement whereas macro-scale mechanical properties were poor. The inversion of the mechanical properties at different scale length was attributed to the porosity, CNT clustering, CNT-splat adhesion and Al 4C3 formation at the CNT/matrix interface. The Dispersion parameter (DP) was more sensitive than Clustering parameter (CP) in measuring degree of CNT distribution in the matrix.

Leaching of S-metolachlor, terbuthylazine, desethyl-terbuthylazine, mesotrione, flufenacet, isoxaflutole, and diketonitrile in field lysimeters as affected by the time elapsed between spraying and first leaching event.

PubMed

Milan, Marco; Ferrero, Aldo; Fogliatto, Silvia; Piano, Serenella; Vidotto, Francesco

2015-01-01

The effect of elapsed time between spraying and first leaching event on the leaching behavior of five herbicides (terbuthylazine, S-metolachlor, mesotrione, flufenacet, and isoxaflutole) and two metabolites (desethyl-terbuthylazine and diketonitrile) was evaluated in a 2011-2012 study in northwest Italy. A battery of 12 lysimeters (8.4 m(2) long with a depth of 1.8 m) were used in the study, each filled with silty-loam soil and treated during pre-emergence with the selected herbicides by applying a mixture of commercial products Lumax (4 L ha(-1)) and Merlin Gold (1 L ha(-1)). During treatment periods, no gravity water was present in lysimeters. Irrigation events capable of producing leaching (40 mm) were conducted on independent groups of three lysimeters on 1 day after treatment (1 DAT), 7 DAT, 14 DAT, and 28 DAT. The series was then repeated 14 days later. Leachate samples were collected a few days after irrigation; compounds were extracted by solid phase extraction and analyzed by high-performance liquid chromatography and gas chromatography-mass spectrometry. Under study conditions, terbuthylazine and S-metolachlor showed the highest leaching potentials. Specifically, S-metolachlor concentrations were always found above 0.25 µg L(-1). Desethyl-terbuthylazine was often detected in leached waters, in most cases at concentrations above 0.1 µg L(-1). Flufenacet leached only when irrigation occurred close to the time of herbicide spraying. Isoxaflutole and mesotrione were not measured (<0.1 µg L(-1)), while diketonitrile was detected in concentrations above 0.1 µg L(-1) on 1 DAT in 2011 only.

Controlling liquid splash on superhydrophobic surfaces by a vesicle surfactant.

PubMed

Song, Meirong; Ju, Jie; Luo, Siqi; Han, Yuchun; Dong, Zhichao; Wang, Yilin; Gu, Zhen; Zhang, Lingjuan; Hao, Ruiran; Jiang, Lei

2017-03-01

Deposition of liquid droplets on solid surfaces is of great importance to many fundamental scientific principles and technological applications, such as spraying, coating, and printing. For example, during the process of pesticide spraying, more than 50% of agrochemicals are lost because of the undesired bouncing and splashing behaviors on hydrophobic or superhydrophobic leaves. We show that this kind of splashing on superhydrophobic surfaces can be greatly inhibited by adding a small amount of a vesicular surfactant, Aerosol OT. Rather than reducing splashing by increasing the viscosity via polymer additives, the vesicular surfactant confines the motion of liquid with the help of wettability transition and thus inhibits the splash. Significantly, the vesicular surfactant exhibits a distinguished ability to alter the surface wettability during the first inertial spreading stage of ~2 ms because of its dense aggregates at the air/water interface. A comprehensive model proposed by this idea could help in understanding the complex interfacial interactions at the solid/liquid/air interface.

Controlling liquid splash on superhydrophobic surfaces by a vesicle surfactant

PubMed Central

Song, Meirong; Ju, Jie; Luo, Siqi; Han, Yuchun; Dong, Zhichao; Wang, Yilin; Gu, Zhen; Zhang, Lingjuan; Hao, Ruiran; Jiang, Lei

2017-01-01

Deposition of liquid droplets on solid surfaces is of great importance to many fundamental scientific principles and technological applications, such as spraying, coating, and printing. For example, during the process of pesticide spraying, more than 50% of agrochemicals are lost because of the undesired bouncing and splashing behaviors on hydrophobic or superhydrophobic leaves. We show that this kind of splashing on superhydrophobic surfaces can be greatly inhibited by adding a small amount of a vesicular surfactant, Aerosol OT. Rather than reducing splashing by increasing the viscosity via polymer additives, the vesicular surfactant confines the motion of liquid with the help of wettability transition and thus inhibits the splash. Significantly, the vesicular surfactant exhibits a distinguished ability to alter the surface wettability during the first inertial spreading stage of ~2 ms because of its dense aggregates at the air/water interface. A comprehensive model proposed by this idea could help in understanding the complex interfacial interactions at the solid/liquid/air interface. PMID:28275735

Erosion and Modifications of Tungsten-Coated Carbon and Copper Under High Heat Flux

NASA Astrophysics Data System (ADS)

Liu, Xiang; S, Tamura; K, Tokunaga; N, Yoshida; Zhang, Fu; Xu, Zeng-yu; Ge, Chang-chun; N, Noda

2003-08-01

Tungsten-coated carbon and copper was prepared by vacuum plasma spraying (VPS) and inert gas plasma spraying (IPS), respectively. W/CFC (Tungsten/Carbon Fiber-Enhanced material) coating has a diffusion barrier that consists of W and Re multi-layers pre-deposited by physical vapor deposition on carbon fiber-enhanced materials, while W/Cu coating has a graded transition interface. Different grain growth processes of tungsten coatings under stable and transient heat loads were observed, their experimental results indicated that the recrystallizing temperature of VPS-W coating was about 1400 °C and a recrystallized columnar layer of about 30 μm thickness was formed by cyclic heat loads of 4 ms pulse duration. Erosion and modifications of W/CFC and W/Cu coatings under high heat load, such as microstructure changes of interface, surface plastic deformations and cracks, were investigated, and the erosion mechanism (erosion products) of these two kinds of tungsten coatings under high heat flux was also studied.

Thermal Shock Damage and Microstructure Evolution of Thermal Barrier Coatings on Mar-M247 Superalloy in a Combustion Gas Environment

NASA Astrophysics Data System (ADS)

Mei, Hui

2012-06-01

The effect of preoxidation on the thermal shock of air plasma sprayed thermal barrier coatings (TBCs) was completely investigated in a combustion gas environment by burning jet fuel with high speed air. Results show that with increasing cycles, the as-oxidized TBCs lost more weight and enlarged larger spallation area than the as-sprayed ones. Thermally grown oxide (TGO) growth and thermal mismatch stress were proven to play critical roles on the as-oxidized TBC failure. Two types of significant cracks were identified: the type I crack was vertical to the TGO interface and the type II crack was parallel to the TGO interface. The former accelerated the TGO growth to develop the latter as long as the oxidizing gas continuously diffused inward and then oxidized the more bond coat (BC). The preoxidation treatment directly increased the TGO thickness, formed the parallel cracks earlier in the TGO during the thermal shocks, and eventually resulted in the worse thermal shock resistance.

The impact of atomization on the surface composition of spray-dried milk droplets.

PubMed

Foerster, Martin; Gengenbach, Thomas; Woo, Meng Wai; Selomulya, Cordelia

2016-04-01

The dominant presence of fat at the surface of spray-dried milk powders has been widely reported in the literature and described as resulting in unfavourable powder properties. The mechanism(s) causing this phenomenon are yet to be clearly identified. A systematic investigation of the component distribution in atomized droplets and spray-dried particles consisting of model milk systems with different fat contents demonstrated that atomization strongly influences the final surface composition. Cryogenic flash-freezing of uniform droplets from a microfluidic jet nozzle directly after atomization helped to distinguish the influence of the atomization stage from the drying stage. It was confirmed that the overrepresentation of fat on the surface is independent of the atomization technique, including a pressure-swirl single-fluid spray nozzle and a pilot-scale rotary disk spray dryer commonly used in industry. It is proposed that during the atomization stage a disintegration mechanism along the oil-water interface of the fat globules causes the surface predominance of fat. X-ray photoelectron spectroscopic measurements detected the outermost fat layer and some adjacent protein present on both atomized droplets and spray-dried particles. Confocal laser scanning microscopy gave a qualitative insight into the protein and fat distribution throughout the cross-sections, and confirmed the presence of a fat film along the particle surface. The film remained on the surface in the subsequent drying stage, while protein accumulated underneath, driven by diffusion. The results demonstrated that atomization induces component segregation and fat-rich surfaces in spray-dried milk powders, and thus these cannot be prevented by adjusting the spray drying conditions. Copyright © 2016 Elsevier B.V. All rights reserved.

Microchip electrospray: improvements in spray and signal stability during gradient elution by an inverted postcolumn makeup flow.

PubMed

Jung, Stephanie; Effelsberg, Uwe; Tallarek, Ulrich

2011-12-01

Dynamic changes in mobile phase composition during high-performance liquid chromatography (HPLC) gradient elution coupled to mass spectrometry (MS) sensitively affect electrospray modes. We investigate the impact of the eluent composition on spray stability and MS response by infusion and injection experiments with a small tetrapeptide in water-acetonitrile mixtures. The employed HPLC/electrospray (ESI)-MS configuration uses a microchip equipped with an enrichment column, a separation column, and a makeup flow (MUF) channel. One nano pump is connected to the separation column, while a second one delivers solvent of exactly inverted composition to the MUF channel. Both solvent streams are united behind the separation column, before the ESI tip, such that the resulting electrosprayed solution always has identical composition during a gradient elution. Analyte peak parameters without and with MUF compensation are determined and discussed with respect to the electrospray mode and eluent composition. The postcolumn MUF significantly improves spray and signal stability over the entire solvent gradient, without compromising the performance of the HPLC separation column. It can also be conveniently implemented on microchip platforms.

Relative gravimeter prototype based on micro electro mechanical system

NASA Astrophysics Data System (ADS)

Rozy, A. S. A.; Nugroho, H. A.; Yusuf, M.

2018-03-01

This research to make gravity measurement system by utilizing micro electro mechanical system based sensor in Gal order. System design consists of three parts, design of hardware, software, and interface. The design of the hardware include of designing the sensor design to measure the value of a stable gravity acceleration. The ADXL345 and ADXL335 sensors are tuned to obtain stable measurements. The design of the instrumentation system the next stage by creating a design to integrate between the sensor, microcontroller, and GPS. The design of programming algorithm is done with Arduino IDE software. The interface design uses a 20x4 LCD display to display the gravity acceleration value and store data on the storage media. The system uses a box made of iron and plate leveling to minimize measurement errors. The sensor test shows the ADXL345 sensor has a more stable value. The system is examined by comparing with gravity measurement of gravimeter A-10 results in Bandung observation post. The result of system test resulted the average of system correction value equal to 0.19 Gal. The system is expected to use for mineral exploration, water supply analyze, and earthquake precursor.

Wireless opto-electro neural interface for experiments with small freely behaving animals.

PubMed

Jia, Yaoyao; Khan, Wasif; Lee, Byunghun; Fan, Bin; Madi, Fatma; Weber, Arthur; Li, Wen; Ghovanloo, Maysam

2018-05-25

We have developed a wireless opto-electro interface (WOENI) device, which combines electrocorticogram (ECoG) recording and optical stimulation for bi-directional neuromodulation on small, freely behaving animals, such as rodents. The device is comprised of two components, a detachable headstage and an implantable polyimide-based substrate. The headstage establishes a Bluetooth Low Energy (BLE) bi-directional data communication with an external custom-designed USB dongle for receiving user commands and optogenetic stimulation patterns, and sending digitalized ECoG data. The functionality and stability of the device were evaluated in vivo on freely behaving rats. When the animal received optical stimulation on the primary visual cortex (V1) and visual stimulation via eyes, spontaneous changes in ECoG signals were recorded from both left and right V1 during 4 consecutive experiments with 7-day intervals over a time span of 21 days following device implantation. Immunostained tissue analyses showed results consistent with ECoG analyses, validating the efficacy of optical stimulation to upregulate the activity of cortical neurons expressing ChR2. The proposed WOENI device is potentially a versatile tool in the studies that involve long-term optogenetic neuromodulation. © 2018 IOP Publishing Ltd.

Development of 6-DOF painting robot control system

NASA Astrophysics Data System (ADS)

Huang, Junbiao; Liu, Jianqun; Gao, Weiqiang

2017-01-01

With the development of society, the spraying technology of manufacturing industry in China has changed from the manual operation to the 6-DOF (Degree Of Freedom)robot automatic spraying. Spraying painting robot can not only complete the work which does harm to human being, but also improve the production efficiency and save labor costs. Control system is the most critical part of the 6-DOF robots, however, there is still a lack of relevant technology research in China. It is very necessary to study a kind of control system of 6-DOF spraying painting robots which is easy to operation, and has high efficiency and stable performance. With Googol controller platform, this paper develops programs based on Windows CE embedded systems to control the robot to finish the painting work. Software development is the core of the robot control system, including the direct teaching module, playback module, motion control module, setting module, man-machine interface, alarm module, log module, etc. All the development work of the entire software system has been completed, and it has been verified that the entire software works steady and efficient.

Suppression of dislocations by Sb spray in the vicinity of InAs/GaAs quantum dots

PubMed Central

2014-01-01

The effect of Sb spray prior to the capping of a GaAs layer on the structure and properties of InAs/GaAs quantum dots (QDs) grown by molecular beam epitaxy (MBE) is studied by cross-sectional high-resolution transmission electron microscopy (HRTEM). Compared to the typical GaAs-capped InAs/GaAs QDs, Sb-sprayed QDs display a more uniform lens shape with a thickness of about 3 ~ 4 nm rather than the pyramidal shape of the non-Sb-sprayed QDs. Particularly, the dislocations were observed to be passivated in the InAs/GaAs interface region and even be suppressed to a large extent. There are almost no extended dislocations in the immediate vicinity of the QDs. This result is most likely related to the formation of graded GaAsSb immediately adjacent to the InAs QDs that provides strain relief for the dot/capping layer lattice mismatch. PACS 81.05.Ea; 81.07.-b; 81.07.Ta PMID:24948897

Matching refractive indices of two fluids and finding interfacial tension for the purpose of fuel spray imaging

NASA Astrophysics Data System (ADS)

Liang, Y. H.

2017-06-01

This study attempts to prepare a fluid pair for use in spray dynamics investigations. Better understanding the behavior of fuel sprays is one of the things that can help improve the efficiency of internal combustion engines. To address the scattering issue in current imaging methods, the refractive index difference between the injected fluid and the medium that it is injected into is eliminated. Two immiscible fluids (sucrose solution and silicone oil) with the same refractive index was identified, their surface tension to build a model fluid engine system injection was also studied. At the same time, Weber number is found to help correct the difference. Results show that 63.7% mass sucrose solution has the same refractive index as silicone oil, and the sucrose solution/silicone oil interface has a surface tension of 0.08941 N/m, which is roughly four times larger than that of ethanol/air. This means using the sucrose/silicone oil fluid pair to model fuel spray will involve some adjustments to be accurate.

New aspects in electrostimulation of the heart.

PubMed

Schaldach, M

1995-01-01

The interaction of the autonomic nervous system (ANS) and the heart is characterized by a new interdisciplinary field known as neurocardiology which presents the newest strategy for electro-cardiostimulation. In this context, the reestablishment of chronotropy with physiological, closed-loop pacing, as well as the prevention and treatment of a malignant arrhythmia by ANS modulation, is of the highest priority. The main objective toward this goal consists of appropriate monitoring of the autonomic balance and stimulation, respectively, so that neuromodulation of the cardiac efferents can be established. The electrode, as a sensor and an actuator, with its interface on the cellular level becomes of essential importance. The electrode-myocardium interface is determined by the structure of the Helmholtz double layer with regard to its physical, electrochemical, and physiological behavior. The transportation of electrons across the boundary, as well as the electro-chemical reactions determining the biocompatibility of the interface, can be improved by the microstructure of the solid component by creating a fractal surface coating with titanium-nitride or iridium. Experimental and clinical results have demonstrated that the fractal structure ensures negligible polarization as well as improved detection performance, thus, detecting the evoked response of the myocardial cells makes it possible to monitor the neural response of the myocardium as a consequence of a superimposed chronotropic disturbance. The stimulation electrode also monitors the sympathetic activity extracted from intracardiac impedance measurements, thereby providing a new principle of rate adaptation in which the pacemaker is an integral part of the ANS, reestablishing normal chronotropy. Further advantages of the improved electrode interface performance open new aspects in the treatment and prevention of tachyarrhythmia, and in the follow-up of transplanted hearts for the prevention of the rejection processes.

Electro-optic tracking R&D for defense surveillance

NASA Astrophysics Data System (ADS)

Sutherland, Stuart; Woodruff, Chris J.

1995-09-01

Two aspects of work on automatic target detection and tracking for electro-optic (EO) surveillance are described. Firstly, a detection and tracking algorithm test-bed developed by DSTO and running on a PC under Windows NT is being used to assess candidate algorithms for unresolved and minimally resolved target detection. The structure of this test-bed is described and examples are given of its user interfaces and outputs. Secondly, a development by Australian industry under a Defence-funded contract, of a reconfigurable generic track processor (GTP) is outlined. The GTP will include reconfigurable image processing stages and target tracking algorithms. It will be used to demonstrate to the Australian Defence Force automatic detection and tracking capabilities, and to serve as a hardware base for real time algorithm refinement.

Polymer waveguides for electro-optical integration in data centers and high-performance computers.

PubMed

Dangel, Roger; Hofrichter, Jens; Horst, Folkert; Jubin, Daniel; La Porta, Antonio; Meier, Norbert; Soganci, Ibrahim Murat; Weiss, Jonas; Offrein, Bert Jan

2015-02-23

To satisfy the intra- and inter-system bandwidth requirements of future data centers and high-performance computers, low-cost low-power high-throughput optical interconnects will become a key enabling technology. To tightly integrate optics with the computing hardware, particularly in the context of CMOS-compatible silicon photonics, optical printed circuit boards using polymer waveguides are considered as a formidable platform. IBM Research has already demonstrated the essential silicon photonics and interconnection building blocks. A remaining challenge is electro-optical packaging, i.e., the connection of the silicon photonics chips with the system. In this paper, we present a new single-mode polymer waveguide technology and a scalable method for building the optical interface between silicon photonics chips and single-mode polymer waveguides.

The development of a dynamic software for the user interaction from the geographic information system environment with the database of the calibration site of the satellite remote electro-optic sensors

NASA Astrophysics Data System (ADS)

Zyelyk, Ya. I.; Semeniv, O. V.

2015-12-01

The state of the problem of the post-launch calibration of the satellite electro-optic remote sensors and its solutions in Ukraine is analyzed. The database is improved and dynamic services for user interaction with database from the environment of open geographical information system Quantum GIS for information support of calibration activities are created. A dynamic application under QGIS is developed, implementing these services in the direction of the possibility of data entering, editing and extraction from the database, using the technology of object-oriented programming and of modern complex program design patterns. The functional and algorithmic support of this dynamic software and its interface are developed.

Combined electrophoresis-electrospray interface and method

DOEpatents

Smith, Richard D. [Richland, WA; Udseth, Harold R. [Richland, WA; Olivares, Jose A. [Los Alamos, NM

1994-10-18

A system and method for analyzing molecular constituents of a composition sample includes: forming a solution of the sample, separating the solution by capillary electrophoresis into an eluent of constituents longitudinally separated according to their relative electrophoretic mobilities, electrospraying the eluent to form a charged spray in which the molecular constituents have a temporal distribution; and detecting or collecting the separated constituents in accordance with the temporal distribution in the spray. A first high-voltage (e.g., 5-100 KVDC) is applied to the solution. The spray is charged by applying a second high voltage (e.g., .+-.2-8 KVDC) between the eluent at the capillary exit and a cathode spaced in front of the exit. A complete electrical circuit is formed by a conductor which directly contacts the eluent at the capillary exit, or by conduction through a sheath electrode discharged in an annular sheath flow about the capillary exit.

Combined electrophoresis-electrospray interface and method

DOEpatents

Smith, R.D.; Udseth, H.R.; Olivares, J.A.

1994-10-18

A system and method for analyzing molecular constituents of a composition sample include: forming a solution of the sample, separating the solution by capillary electrophoresis into an eluent of constituents longitudinally separated according to their relative electrophoretic mobilities, electrospraying the eluent to form a charged spray in which the molecular constituents have a temporal distribution; and detecting or collecting the separated constituents in accordance with the temporal distribution in the spray. A first high-voltage (e.g., 5--100 kVDC) is applied to the solution. The spray is charged by applying a second high voltage (e.g.,{+-}2--8 kVDC) between the eluent at the capillary exit and a cathode spaced in front of the exit. A complete electrical circuit is formed by a conductor which directly contacts the eluent at the capillary exit, or by conduction through a sheath electrode discharged in an annular sheath flow about the capillary exit. 21 figs.

Combined electrophoresis-electrospray interface and method

DOEpatents

Smith, R.P.; Udseth, H.R.; Olivares, J.A.

1989-12-05

A system and method for analyzing molecular constituents of a composition sample includes: forming a solution of the sample, separating the solution by capillary electrophoresis into an eluent of constituents longitudinally separated according to their relative electrophoretic mobilities, electrospraying the eluent to form a charged spray in which the molecular constituents have a temporal distribution; and detecting or collecting the separated constituents in accordance with the temporal distribution in the spray. A first high-voltage (e.g., 5--100 kVDC) is applied to the solution. The spray is charged by applying a second high voltage (e.g., [+-]2--8 kVDC) between the eluent at the capillary exit and a cathode spaced in front of the exit. A complete electrical circuit is formed by a conductor which directly contacts the eluent at the capillary exit, or by conduction through a sheath electrode discharged in an annular sheath flow about the capillary exit. 21 figs.

Combined electrophoresis-electrospray interface and method

DOEpatents

Smith, Richard P.; Udseth, Harold R.; Olivares, Jose A.

1989-01-01

A system and method for analyzing molecular constituents of a composition sample includes: forming a solution of the sample, separating the solution by capillary electrophoresis into an eluent of constituents longitudinally separated according to their relative electrophoretic mobilities, electrospraying the eluent to form a charged spray in which the molecular constituents have a temporal distribution; and detecting or collecting the separated constituents in accordance with the temporal distribution in the spray. A first high-voltage (e.g., 5-100 KVDC) is applied to the solution. The spray is charged by applying a second high voltage (e.g., .+-.2-8 KVDC) between the eluent at the capillary exit and a cathode spaced in front of the exit. A complete electrical circuit is formed by a conductor which directly contacts the eluent at the capillary exit, or by conduction through a sheath electrode discharged in an annular sheath flow about the capillary exit.

Molecular Momentum Transport at Fluid-Solid Interfaces in MEMS/NEMS: A Review

PubMed Central

Cao, Bing-Yang; Sun, Jun; Chen, Min; Guo, Zeng-Yuan

2009-01-01

This review is focused on molecular momentum transport at fluid-solid interfaces mainly related to microfluidics and nanofluidics in micro-/nano-electro-mechanical systems (MEMS/NEMS). This broad subject covers molecular dynamics behaviors, boundary conditions, molecular momentum accommodations, theoretical and phenomenological models in terms of gas-solid and liquid-solid interfaces affected by various physical factors, such as fluid and solid species, surface roughness, surface patterns, wettability, temperature, pressure, fluid viscosity and polarity. This review offers an overview of the major achievements, including experiments, theories and molecular dynamics simulations, in the field with particular emphasis on the effects on microfluidics and nanofluidics in nanoscience and nanotechnology. In Section 1 we present a brief introduction on the backgrounds, history and concepts. Sections 2 and 3 are focused on molecular momentum transport at gas-solid and liquid-solid interfaces, respectively. Summary and conclusions are finally presented in Section 4. PMID:20087458

Electro-optical interfacial effects on a graphene/π-conjugated organic semiconductor hybrid system

PubMed Central

Araujo, Karolline A S; Cury, Luiz A; Matos, Matheus J S; Fernandes, Thales F D; Cançado, Luiz G

2018-01-01

The influence of graphene and retinoic acid (RA) – a π-conjugated organic semiconductor – interface on their hybrid system is investigated. The physical properties of the interface are assessed via scanning probe microscopy, optical spectroscopy (photoluminescence and Raman) and ab initio calculations. The graphene/RA interaction induces the formation of a well-organized π-conjugated self-assembled monolayer (SAM) at the interface. Such structural organization leads to the high optical emission efficiency of the RA SAM, even at room temperature. Additionally, photo-assisted electrical force microscopy, photo-assisted scanning Kelvin probe microscopy and Raman spectroscopy indicate a RA-induced graphene doping and photo-charge generation. Finally, the optical excitation of the RA monolayer generates surface potential changes on the hybrid system. In summary, interface-induced organized structures atop 2D materials may have an important impact on both design and operation of π-conjugated nanomaterial-based hybrid systems. PMID:29600157

Evaluation of asphalt rubber membrane interlayer (ARMI) using the University of Florida's composite system interface cracking (CSIC) test.

DOT National Transportation Integrated Search

2012-05-01

Since the late 1970s, FDOT : has applied an interlayer : of Asphalt Rubber : Membrane Interlayer : (ARMI) to asphalt roadway : surfaces. ARMI layers are : constructed by spraying : asphalt rubber binder onto : the asphalt, covering the : layer with n...

Jet Simulation in a Diesel Engine

NASA Astrophysics Data System (ADS)

Xu, Zhiliang

2005-03-01

We present a numerical study of the jet breakup and spray formation in a diesel engine by the Front Tracking method. The mechanisms of jet breakup and spray formation of a high speed diesel jet injected through a circular nozzle are the key to design a fuel efficient, nonpolluting diesel engine. We conduct the simulations for the jet breakup within a 2D axis-symmetric geometry. Our goal is to model the spray at a micro-physical level, with the creation of individual droplets. The problem is multiscale. The droplets are a few microns in size. The nozzle is about 0.2 mm in diameter and 1 mm in length. To resolve various physical patterns such as vortex, shock waves, vacuum and track droplets and spray, the Burger-Colella adaptive mesh refinement technique is used. To simulate the spray formation, we model mixed vapor-liquid region through a heterogeneous model with dynamic vapor bubble insertion. The formation of the cavitation is represented by the dynamic creation of vapor bubbles. On the liquid/vapor interface, a phase transition problem is solved numerically. The phase transition is governed by the compressible Euler equations with heat diffusion. Our solution is a new description for the Riemann problem associated with a phase transition in a fully compressible fluid.

Microstructured Polymer Blend Surfaces Produced by Spraying Functional Copolymers and Their Blends

PubMed Central

Vargas-Alfredo, Nelson; Rodríguez Hernández, Juan

2016-01-01

We described the fabrication of functional and microstructured surfaces from polymer blends by spray deposition. This simple technique offers the possibility to simultaneously finely tune the microstructure as well as the surface chemical composition. Whereas at lower polymer concentration, randomly distributed surface micropatterns were observed, an increase of the concentration leads to significant changes on these structures. On the one hand, using pure homopolystyrene fiber-like structures were observed when the polymer concentration exceeded 30 mg/mL. Interestingly, the incorporation of 2,3,4,5,6-pentafluorostyrene changed the morphology, and, instead of fibers, micrometer size particles were identified at the surface. These fluorinated microparticles provide superhydrophobic properties leading to surfaces with contact angles above 165°. Equally, in addition to the microstructures provided by the spray deposition, the use of thermoresponsive polymers to fabricate interfaces with responsive properties is also described. Contact angle measurements revealed variations on the surface wettability upon heating when blends of polystyrene and polystyrene-b-poly(dimethylaminoethyl methacrylate) are employed. Finally, the use of spraying techniques to fabricate gradient surfaces is proposed. Maintaining a constant orientation, the surface topography and thus the contact angle varies gradually from the center to the edge of the film depending on the spray angle. PMID:28773555

Transfer matrix method solving interface optical phonons in wurtzite core-multishell nanowires of III-nitrides

NASA Astrophysics Data System (ADS)

Xue, Z. X.; Qu, Y.; Xie, H.; Ban, S. L.

2016-12-01

Within the framework of dielectric continuum and Loudon's uniaxial crystal models, the transfer matrix method (TMM) is developed to investigate interface optical phonons (IOPs) in cylindrical wurtzite core-multishell nanowires (CMSNWs) consisting of ternary mixed crystals (TMCs). The IOPs in GaN/InxGa1-xN/InyGa1-yN and GaN/InxGa1-xN/InyGa1-yN/InzGa1-zN CMSNWs are calculated as examples. The results show that there may be several types of IOPs existing in certain frequency regions in CMSNWs for a given component due to the phonon dispersion anisotropy in wurtzite nitrides. The IOPs are classified by possible combinations of the interfaces in CMSNWs. Furthermore, the dispersion relations and electro-static potentials of each kind of IOPs are discussed in detail. The dispersion relations of IOPs in CMSNWs is found to be the combination of that in each nearest two layer CSNW. It can explain the fact that the total branch number of IOPs obey the 2n rule. It is also found that the peak positions of electro-static potentials are decided by the layer component order from the inner layer to outside in CMSNWs. The results indicate that TMM for IOPs is available and can be commodiously extended to other cylindrical wurtzite III-nitride CMSNWs. Based on this method, one can further discuss the IOPs related photoelectric properties in nitride CMSNWs consisting of TMCs.

Electro-responsivity of ionic liquid boundary layers in a polar solvent revealed by neutron reflectance

NASA Astrophysics Data System (ADS)

Pilkington, Georgia A.; Harris, Kathryn; Bergendal, Erik; Reddy, Akepati Bhaskar; Palsson, Gunnar K.; Vorobiev, Alexei; Antzutkin, Oleg. N.; Glavatskih, Sergei; Rutland, Mark W.

2018-05-01

Using neutron reflectivity, the electro-responsive structuring of the non-halogenated ionic liquid (IL) trihexyl(tetradecyl)phosphonium-bis(mandelato)borate, [P6,6,6,14][BMB], has been studied at a gold electrode surface in a polar solvent. For a 20% w/w IL mixture, contrast matched to the gold surface, distinct Kiessig fringes were observed for all potentials studied, indicative of a boundary layer of different composition to that of the bulk IL-solvent mixture. With applied potential, the amplitudes of the fringes from the gold-boundary layer interface varied systematically. These changes are attributable to the differing ratios of cations and anions in the boundary layer, leading to a greater or diminished contrast with the gold electrode, depending on the individual ion scattering length densities. Such electro-responsive changes were also evident in the reflectivities measured for the pure IL and a less concentrated (5% w/w) IL-solvent mixture at the same applied potentials, but gave rise to less pronounced changes. These measurements, therefore, demonstrate the enhanced sensitivity achieved by contrast matching the bulk solution and that the structure of the IL boundary layers formed in mixtures is strongly influenced by the bulk concentration. Together these results represent an important step in characterising IL boundary layers in IL-solvent mixtures and provide clear evidence of electro-responsive structuring of IL ions in their solutions with applied potential.

High temperature low friction surface coating

DOEpatents

Bhushan, Bharat

1980-01-01

A high temperature, low friction, flexible coating for metal surfaces which are subject to rubbing contact includes a mixture of three parts graphite and one part cadmium oxide, ball milled in water for four hours, then mixed with thirty percent by weight of sodium silicate in water solution and a few drops of wetting agent. The mixture is sprayed 12-15 microns thick onto an electro-etched metal surface and air dried for thirty minutes, then baked for two hours at 65.degree. C. to remove the water and wetting agent, and baked for an additional eight hours at about 150.degree. C. to produce the optimum bond with the metal surface. The coating is afterwards burnished to a thickness of about 7-10 microns.

In2O3-based multicomponent metal oxide films and their prospects for thermoelectric applications

NASA Astrophysics Data System (ADS)

Korotcenkov, G.; Brinzari, V.; Cho, B. K.

2016-02-01

Thermoelectric properties of In2O3-SnO2-based multi-component metal oxide films formed by spray pyrolysis method are studied. It is shown that the introduction of additional components such as gallium and zinc can control the parameters of the deposited layers. At that, the doping with gallium is more effective for optimization of the efficiency of the thermoelectric conversion. The explanation of the observed changes in the electro-physical and thermoelectric properties of the films at the composition change is given. It is found that the main changes in the properties of multicomponent metal oxide films take place at concentrations of dopants which correspond to their limit solubility in the dominant oxide.

Bilayer Suspension Plasma-Sprayed Thermal Barrier Coatings with Enhanced Thermal Cyclic Lifetime: Experiments and Modeling

NASA Astrophysics Data System (ADS)

Gupta, Mohit; Kumara, Chamara; Nylén, Per

2017-08-01

Suspension plasma spraying (SPS) has been shown as a promising process to produce porous columnar strain tolerant coatings for thermal barrier coatings (TBCs) in gas turbine engines. However, the highly porous structure is vulnerable to crack propagation, especially near the topcoat-bondcoat interface where high stresses are generated due to thermal cycling. A topcoat layer with high toughness near the topcoat-bondcoat interface could be beneficial to enhance thermal cyclic lifetime of SPS TBCs. In this work, a bilayer coating system consisting of first a dense layer near the topcoat-bondcoat interface followed by a porous columnar layer was fabricated by SPS using Yttria-stabilised zirconia suspension. The objective of this work was to investigate if the bilayer topcoat architecture could enhance the thermal cyclic lifetime of SPS TBCs through experiments and to understand the effect of the column gaps/vertical cracks and the dense layer on the generated stresses in the TBC during thermal cyclic loading through finite element modeling. The experimental results show that the bilayer TBC had significantly higher lifetime than the single-layer TBC. The modeling results show that the dense layer and vertical cracks are beneficial as they reduce the thermally induced stresses which thus increase the lifetime.

Review: Current applications and challenges for liquid chromatography coupled to isotope ratio mass spectrometry (LC/IRMS).

PubMed

Godin, Jean-Philippe; McCullagh, James S O

2011-10-30

High-precision isotope analysis is recognized as an essential research tool in many fields of study. Until recently, continuous flow isotope ratio mass spectrometry (CF-IRMS) was available via an elemental analyzer or a gas chromatography inlet system for compound-specific analysis of light stable isotopes. In 2004, however, an interface that coupled liquid chromatography with IRMS (LC/IRMS) became commercially available for the first time. This brought the capability for new areas of application, in particular enabling compound-specific δ(13)C analysis of non-volatile, aqueous soluble, compounds from complex mixtures. The interface design brought with it several analytical constraints, however, in particular a lack of compatibility with certain types of chromatography as well as limited flow rates and mobile phase compositions. Routine LC/IRMS methods have, however, been established for measuring the δ(13)C isotopic ratios of underivatized individual compounds for application in archeology, nutrition and physiology, geochemistry, hydrology, soil science and food authenticity. Seven years after its introduction, we review the technical advances and constraints, methodological developments and new applications of liquid chromatography coupled to isotope ratio mass spectrometry. Copyright © 2011 John Wiley & Sons, Ltd.

Validated hydrophilic interaction LC-MS/MS method for simultaneous quantification of dacarbazine and 5-amino-4-imidazole-carboxamide in human plasma.

PubMed

Liu, Yanhong; Zhang, Weihua; Yang, Yuhui

2008-10-19

A hydrophilic interaction high performance liquid chromatography-tandem mass spectrometric method has been developed and validated for simultaneous quantification of dacarbazine (DTIC) and its terminal metabolite, 5-amino-4-imidazole-carboxamide (AIC) in human plasma. The plasma samples are first extracted by a C8+SCX mixed-mode 96-well plate to extend the extraction stability of DTIC and AIC. The extracted residues are further cleaned by a primary and secondary amine (PSA) adsorbent for minimization of matrix effect. Analyses are done on an Amide-80 HPLC column coupled to a tandem mass spectrometer fitted with an atmospheric pressure turbo ion spray ionization interface in the positive-ion mode. Both DTIC and AIC have reproducible retention times on the Amide-80 HPLC column. This type of column not only has an excellent column life (over 4000 injections), but also has zero carryover effect. The injection volume should be limited at 10 microL or less to avoid the peak splitting. The validated concentration ranges are from 0.5 to 500 ng/mL for DTIC and from 2.0 to 500 ng/mL for AIC. The validated method has been successfully applied to determine the pharmacokinetic profiles for human patients receiving DTIC infusions.

Fundamental and Applied Investigations in Atomic Spectrometric Analysis

NASA Astrophysics Data System (ADS)

Wu, Min

Simultaneous laser-excited fluorescence and absorption measurements were performed and the results have revealed that any interference caused by easily ionized elements does not originate from variations in analyte emission (quantum) efficiency. A closely related area, the roles of wet and dry aerosols in the matrix interference are clarified through spatially resolved imaging of the plasma by a charged coupled device camera. To eliminate matrix interference effects practically, various methods have been developed based on the above studies. The use of column pre-concentration with flow injection analysis has been found to provide a simple solution for reducing interference effects and increasing sensitivity of elemental analysis. A novel mini-spray chamber was invented. The new vertical rotary spray chamber combines gravitational, centrifugal, turbulent, and impact droplet segregation mechanisms to achieve a higher efficiency of small-droplet formation in a nebulized sample spray. As a result, it offers also higher sample-transport efficiency, lower memory effects, and improved analytical figures of merit over existing devices. This new device was employed with flow injection analysis to simulate an interface for coupling high performance liquid chromatography (HPLC) to a microwave plasma for chromatographic detection. The detection limits for common metallic elements are in the range of 5-50 mug/mL, and are degraded only twofold when the elements are presented in an organic solvent such as ethanol or methanol. Other sample-introduction schemes have also been investigated to improve sample-introduction technology. The direct coupling of hydride-generation techniques to the helium microwave plasma torch was evaluated for the determination of arsenic, antimony and tin by atomic emission spectrometry. A manually controlled peristaltic pump was modified for computer control and continuous flow injection was evaluated for standard calibration and trace elemental analysis. The present work evaluates the coupling of a novel microwave plasma torch with a quadruple mass spectrometer for the detection of ionic species from different nonmetals. Initial work performed with such a combination is demonstrated to be not only practicable but also promising. Detection limits for the halogens (F, Cl, Br, I) and S are in the range between 10 ng/mL and 1mug/mL. Further improvements have been realized through the use of chemical -vapor generation and by optimization of the plasma and the mass spectrometer. (Abstract shortened by UMI.).

Evaluation of asphalt rubber membrane interlayer (ARMI) using the University of Florida's composite system interface cracking (CSIC) test [summary].

DOT National Transportation Integrated Search

2012-01-01

Since the late 1970s, FDOT : has applied an interlayer : of Asphalt Rubber : Membrane Interlayer : (ARMI) to asphalt roadway : surfaces. ARMI layers are : constructed by spraying : asphalt rubber binder onto : the asphalt, covering the : layer with n...

Modeling Droplet Heat and Mass Transfer during Spray Bar Pressure Control of the Multipurpose Hydrogen Test Bed (MHTB) Tank in Normal Gravity

NASA Technical Reports Server (NTRS)

Kartuzova, O.; Kassemi, M.

2016-01-01

A CFD model for simulating pressure control in cryogenic storage tanks through the injection of a subcooled liquid into the ullage is presented and applied to the 1g MHTB spray bar cooling experiments. An Eulerian-Lagrangian approach is utilized to track the spray droplets and capture the interaction between the discrete droplets and the continuous ullage phase. The spray model is coupled with the VOF model by performing particle tracking in the ullage, removing particles from the ullage when they reach the interface, and then adding their contributions to the liquid. A new model for calculating the droplet-ullage heat and mass transfer is developed. In this model, a droplet is allowed to warm up to the saturation temperature corresponding to the ullage vapor pressure, after which it evaporates while remaining at the saturation temperature. The droplet model is validated against the results of the MHTB spray-bar cooling experiments with 50% and 90% tank fill ratios. The predictions of the present T-sat based model are compared with those of a previously developed kinetic-based droplet mass transfer model. The predictions of the two models regarding the evolving tank pressure and temperature distributions, as well as the droplets' trajectories and temperatures, are examined and compared in detail. Finally, the ullage pressure and local vapor and liquid temperature evolutions are validated against the corresponding data provided by the MHTB spray bar mixing experiment.

On the transition between two-phase and single-phase interface dynamics in multicomponent fluids at supercritical pressures

NASA Astrophysics Data System (ADS)

Dahms, Rainer N.; Oefelein, Joseph C.

2013-09-01

A theory that explains the operating pressures where liquid injection processes transition from exhibiting classical two-phase spray atomization phenomena to single-phase diffusion-dominated mixing is presented. Imaging from a variety of experiments have long shown that under certain conditions, typically when the pressure of the working fluid exceeds the thermodynamic critical pressure of the liquid phase, the presence of discrete two-phase flow processes become diminished. Instead, the classical gas-liquid interface is replaced by diffusion-dominated mixing. When and how this transition occurs, however, is not well understood. Modern theory still lacks a physically based model to quantify this transition and the precise mechanisms that lead to it. In this paper, we derive a new model that explains how the transition occurs in multicomponent fluids and present a detailed analysis to quantify it. The model applies a detailed property evaluation scheme based on a modified 32-term Benedict-Webb-Rubin equation of state that accounts for the relevant real-fluid thermodynamic and transport properties of the multicomponent system. This framework is combined with Linear Gradient Theory, which describes the detailed molecular structure of the vapor-liquid interface region. Our analysis reveals that the two-phase interface breaks down not necessarily due to vanishing surface tension forces, but due to thickened interfaces at high subcritical temperatures coupled with an inherent reduction of the mean free molecular path. At a certain point, the combination of reduced surface tension, the thicker interface, and reduced mean free molecular path enter the continuum length scale regime. When this occurs, inter-molecular forces approach that of the multicomponent continuum where transport processes dominate across the interfacial region. This leads to a continuous phase transition from compressed liquid to supercritical mixture states. Based on this theory, a regime diagram for liquid injection is developed that quantifies the conditions under which classical sprays transition to dense-fluid jets. It is shown that the chamber pressure required to support diffusion-dominated mixing dynamics depends on the composition and temperature of the injected liquid and ambient gas. To illustrate the method and analysis, we use conditions typical of diesel engine injection. We also present a companion set of high-speed images to provide experimental validation of the presented theory. The basic theory is quite general and applies to a wide range of modern propulsion and power systems such as liquid rockets, gas turbines, and reciprocating engines. Interestingly, the regime diagram associated with diesel engine injection suggests that classical spray phenomena at typical injection conditions do not occur.

Polymer electro-optic waveguide devices: Low-loss etchless fabrication techniques and passive-to-active integration

NASA Astrophysics Data System (ADS)

Geary, Kevin

The development of high-frequency polymer electro-optic modulators has seen steady and significant progress in recent years, yet applications of these promising materials to more complicated integrated optic structures and arrays of devices have been limited primarily due to high optical waveguide loss characteristics. This is unfortunate since a major advantage of polymers as photonic materials is their compatibility with photolithographic processing of large components. In this Dissertation, etchless waveguide writing techniques are presented in order to improve the overall optical insertion loss of electro-optic polymer waveguide devices. These techniques include poling-induced writing, stress-induced waveguide writing, and photobleaching. Using these waveguide writing mechanisms, we have demonstrated straight waveguides, phase modulators, Mach-Zehnder intensity modulators, variable optical attenuators, and multimode interference (MMI) power splitters, all with improved loss characteristics over their etched rib waveguide counterparts. Ultimately, the insertion loss of an integrated optic device is limited by the actual material loss of the core waveguide material. In this Dissertation, passive-to-active polymer waveguide transitions are proposed to circumvent this problem. These transitions are compact, in-plane, self-aligned, and require no tapering of any physical dimensions of the waveguides. By utilizing both the time-dependent and intensity-dependent photobleaching characteristics of electro-optic polymer materials, adiabatic refractive index tapers can be seamlessly coupled to in-plane butt couple transitions, resulting in losses as low as 0.1 dB per interface. By integrating passive polymer planar lightwave circuits with the high-speed phase shifting capability of electro-optic polymers, active wideband photonic devices of increased size and complexity can be realized. Optical fiber-to-device coupling can also result in significant contributions to the overall insertion loss of an integrated electro-optic polymer device. In this Dissertation, we leverage the photobleached refractive index taper component of our proposed passive-to-active polymer waveguide transitions in order to realize a two-dimensional optical mode transformer for improved overall fiber-to-device coupling of electro-optic polymer waveguide devices.

Wireless communication links for brain-machine interface applications

NASA Astrophysics Data System (ADS)

Larson, L.

2016-05-01

Recent technological developments have given neuroscientists direct access to neural signals in real time, with the accompanying ability to decode the resulting information and control various prosthetic devices and gain insight into deeper aspects of cognition. These developments - along with deep brain stimulation for Parkinson's disease and the possible use of electro-stimulation for other maladies - leads to the conclusion that the widespread use electronic brain interface technology is a long term possibility. This talk will summarize the various technical challenges and approaches that have been developed to wirelessly communicate with the brain, including technology constraints, dc power limits, compression and data rate issues.

ElectroMagnetoEncephalography Software: Overview and Integration with Other EEG/MEG Toolboxes

PubMed Central

Peyk, Peter; De Cesarei, Andrea; Junghöfer, Markus

2011-01-01

EMEGS (electromagnetic encephalography software) is a MATLAB toolbox designed to provide novice as well as expert users in the field of neuroscience with a variety of functions to perform analysis of EEG and MEG data. The software consists of a set of graphical interfaces devoted to preprocessing, analysis, and visualization of electromagnetic data. Moreover, it can be extended using a plug-in interface. Here, an overview of the capabilities of the toolbox is provided, together with a simple tutorial for both a standard ERP analysis and a time-frequency analysis. Latest features and future directions of the software development are presented in the final section. PMID:21577273

ElectroMagnetoEncephalography software: overview and integration with other EEG/MEG toolboxes.

PubMed

Peyk, Peter; De Cesarei, Andrea; Junghöfer, Markus

2011-01-01

EMEGS (electromagnetic encephalography software) is a MATLAB toolbox designed to provide novice as well as expert users in the field of neuroscience with a variety of functions to perform analysis of EEG and MEG data. The software consists of a set of graphical interfaces devoted to preprocessing, analysis, and visualization of electromagnetic data. Moreover, it can be extended using a plug-in interface. Here, an overview of the capabilities of the toolbox is provided, together with a simple tutorial for both a standard ERP analysis and a time-frequency analysis. Latest features and future directions of the software development are presented in the final section.

Persistence of azoxystrobin in/on grapes and soil in different grapes growing areas of India.

PubMed

Gajbhiye, Vijay Tularam; Gupta, Suman; Mukherjee, Irani; Singh, Shashi Bala; Singh, Neera; Dureja, Prem; Kumar, Yogesh

2011-01-01

Persistence of azoxystrobin was studied in/on grapes when applied @ 150 g ai ha⁻¹ (recommended dose) and 300 g ai ha⁻¹ (double the recommended dose) in three grapes growing states of India, namely Karnataka, Maharashtra and Tamil Nadu, in the year 2006-2007. A total of five sprays were given at an interval of about 15 days. Grapes and soil samples were collected after 5th spray, extracted and analysed by gas chromatography using electron capture detector. Half life of azoxystrobin on grapes varied from 5.4 to 11.2 days. Residues of azoxystrobin were much below the prescribed MRL (0.5 mg kg⁻¹) after 21 days. The dissipation of azoxystrobin in soil followed first order rate kinetics with an average half life of 8.1 days at the recommended dose of application.

Signal enhancement for gradient reverse-phase high-performance liquid chromatography-electrospray ionization mass spectrometry analysis with trifluoroacetic and other strong acid modifiers by postcolumn addition of propionic acid and isopropanol.

PubMed

Kuhlmann, F E; Apffel, A; Fischer, S M; Goldberg, G; Goodley, P C

1995-12-01

Trifluoroacetic acid (TFA) and other volatile strong acids, used as modifiers in reverse-phase high-performance liquid chromatography, cause signal suppression for basic compounds when analyzed by electrospray ionization mass spectrometry (ESI-MS). Evidence is presented that signal suppression is caused by strong ion pairing between the TFA anion and the protonated sample cation of basic sample molecules. The ion-pairing process "masks" the protonated sample cations from the ESI-MS electric fields by rendering them "neutral. " Weakly basic molecules are not suppressed by this process. The TFA signal suppression effect is independent from the well-known spray problem that electrospray has with highly aqueous solutions that contain TFA. This previously reported spray problem is caused by the high conductivity and surface tension of aqueous TFA solutions. A practical method to enhance the signal for most basic analytes in the presence of signal-suppressing volatile strong acids has been developed. The method employs postcolumn addition of a solution of 75% propionic acid and 25% isopropanol in a ratio 1:2 to the column flow. Signal enhancement is typically 10-50 times for peptides and other small basic molecules. Thus, peptide maps that use ESI-MS for detection can be performed at lower levels, with conventional columns, without the need to use capillary chromatography or reduced mass spectral resolution to achieve satisfactory sensitivity. The method may be used with similar results for heptafluorobutyric acid and hydrochloric acid. A mechanism for TFA signal suppression and signal enhancement by the foregoing method, is proposed.

Science of Decision Making: A Data-Modeling Approach

DTIC Science & Technology

2013-10-01

were separated on a capillary column using the Dionex UltiMate 3000 (Sunnyvale, CA). The resolved peptides were then sprayed into a linear ion trap...database (3–5). These algorithms assign a peptide sequence, along with a matching score of the experimental ion product mass spectrum, to a theoretical ion ...Bacterial Sample Processing Samples were prepared for liquid chromatography (LC) tandem MS (LC– MS/MS) in a similar manner to that previously reported

Spray-Freeze Drying: a Suitable Method for Aerosol Delivery of Antibodies in the Presence of Trehalose and Cyclodextrins.

PubMed

Pouya, Maryam Amini; Daneshmand, Behnaz; Aghababaie, Shabnam; Faghihi, Homa; Vatanara, Alireza

2018-05-08

We aimed to prepare spray-freeze-dried powder of IgG considering physicochemical stability and aerodynamic aspects. Spray-freeze drying (SFD) exposes proteins to various stresses which should be compensated by suitable stabilizers. The competence of cyclodextrins (CDs), namely beta-cyclodextrin (βCD) and hydroxypropyl βCD (HPβCD), at very low concentrations, was investigated in the presence of separate mannitol- and trehalose-based formulations. Spray-freeze-dried preparations were quantified in terms of monomer recovery and conformation by size exclusion chromatography (SEC-HPLC) and Fourier transform infrared (FTIR) spectroscopy, respectively. Differential scanning calorimetry (DSC) and X-ray diffractometry (XRD) were employed to identify the thermal characteristics of powders. Particle morphology was visualized by scanning electron microscopy (SEM). Aerodynamic behavior of powders was checked through an Anderson cascade impactor (ACI). Although all formulations protected antibody from aggregation during the SFD process (aggregation < 1%), mannitol-containing ones failed upon the storage (19.54% in the worst case). Trehalose-HPβCD incomparably preserved the formulation with fine particle fraction (FPF) of 51.29%. Crystallization of mannitol resulted in IgG destabilization upon storage. Although employed concentration of CDs is too low (less than 50:1 molar ratio to protein), they successfully served as stabilizing agents in SFD with perfect improvement in aerosol functionality. Graphical Abstract ᅟ.

Advanced liquid chromatography-mass spectrometry interface based on electron ionization.

PubMed

Cappiello, A; Famiglini, G; Pierini, E; Palma, P; Trufelli, H

2007-07-15

Major progress in interfacing liquid chromatography and electron ionization mass spectrometry is presented. The minimalism of the first prototype, called the Direct-EI interface, has been widely refined, improved, and applied to modern instrumentation. The simple interfacing principle is based on the straight connection between a nanoHPLC system and a mass spectrometer equipped with an EI source forming a solid and reliable unicum resembling the immediacy and straightforwardness of GC/MS. The interface shows a superior performance in the analysis of small-medium molecular weight compounds, especially when compared to its predecessors, and a unique trait that excels particularly in the following aspects: (1) It delivers high-quality, fully library matchable mass spectra of most sub-1 kDa molecules amenable by HPLC. (2) It is a chemical ionization free interface (unless operated intentionally) with accurate reproduction of the expected isotope ion abundances. (3) Response is never influenced by matrix components in the sample or in the mobile phase (nonvolatile salts are also well accepted). A deep evaluation of these aspects is presented and discussed in detail. Other characteristics of the interface performance such as limits of detections, range of linear response, and intra- and interday signal stability were also considered. The usefulness of the interface has been tested in a few real-world applications where matrix components played a detrimental role with other LC/MS techniques.

Determination of geniposide in adjuvant arthritis rat plasma by ultra-high performance liquid chromatography tandem mass spectrometry method and its application to oral bioavailability and plasma protein binding ability studies.

PubMed

Chen, Jian; Wu, Hong; Xu, Guo-Bing; Dai, Miao-Miao; Hu, Shun-Li; Sun, Liang-Liang; Wang, Wei; Wang, Rong; Li, Shu-Pin; Li, Guo-Qiang

2015-04-10

A specific, sensitive and high throughput ultra-high performance liquid chromatography-electrospray ionization tandem mass spectrometric method (UHPLC-ESI-MS/MS) was established and validated to assay geniposide (GE), a promising anti-inflammatory drug, in adjuvant arthritis rat plasma: application to pharmacokinetic and oral bioavailability studies and plasma protein binding ability. Plasma samples were processed by de-proteinised with ice-cold methanol and separated on an ACQUITY UPLC™ HSS C18 column (100 mm × 2.1mm i.d., 1.8 μm particle size) at a gradient flow rate of 0.2 mL/min using acetonitrile-0.1% formic acid in water as mobile phase, and the total run time was 9 min. Mass detection was performed in selected reaction monitoring (SRM) mode with negative electro-spray ionization includes the addition of paeoniflorin (Pae) as an internal standard (IS). The mass transition ion-pair was followed as m/z 387.4 → 122.4 for GE and m/z 479.4 → 449.0 for IS. The calibration curves were linear over the concentration range of 2-50,000 ng/mL with lower limit of quantification of 2 ng/mL. The intra-day and inter-day precisions (RSD, %) of the assay were less than 8.4%, and the accuracy was within ± 6.4% in terms of relative error (RE). Extraction recovery, matrix effect and stability were satisfactory in adjuvant arthritis rat plasma. The UHPLC-ESI-MS/MS method was successfully applied to a pharmacokinetic study of GE after oral administration of depurated GE at 33, 66, 132 mg/kg and intravenous injection at 33, 66, 132 mg/kg in adjuvant arthritis (AA) rats. In addition, it was found that GE has rapid absorption and elimination, low absolute bioavailability, high plasma protein binding ability in AA rats after oral administration within the tested dosage range. It suggested that GE showed slow distribution into the intra- and extracellular space, and the binding rate was not proportionally dependent on plasma concentration of GE when the concentration of GE was below 5.0 μg/mL. Copyright © 2015 Elsevier B.V. All rights reserved.

Improved hydrophilic interaction chromatography LC/MS of heparinoids using a chip with postcolumn makeup flow.

PubMed

Staples, Gregory O; Naimy, Hicham; Yin, Hongfeng; Kileen, Kevin; Kraiczek, Karsten; Costello, Catherine E; Zaia, Joseph

2010-01-15

Heparan sulfate (HS) and heparin are linear, heterogeneous carbohydrates of the glycosaminoglycan (GAG) family that are modified by N-acetylation, N-sulfation, O-sulfation, and uronic acid epimerization. HS interacts with growth factors in the extracellular matrix, thereby modulating signaling pathways that govern cell growth, development, differentiation, proliferation, and adhesion. High-performance liquid chromatography (HPLC)-chip-based hydrophilic interaction liquid chromatography/mass spectrometry has emerged as a method for analyzing the domain structure of GAGs. However, analysis of highly sulfated GAG structures decasaccharide or larger in size has been limited by spray instability in the negative-ion mode. This report demonstrates that addition of postcolumn makeup flow to the amide-HPLC-chip configuration permits robust and reproducible analysis of extended GAG domains (up to degree of polymerization 18) from HS and heparin. This platform provides quantitative information regarding the oligosaccharide profile, degree of sulfation, and nonreducing chain termini. It is expected that this technology will enable quantitative, comparative glycomics profiling of extended GAG oligosaccharide domains of functional interest.

Isolation and Purification of Two Isoflavones from Hericium erinaceum Mycelium by High-Speed Counter-Current Chromatography.

PubMed

He, Jinzhe; Fan, Peng; Feng, Simin; Shao, Ping; Sun, Peilong

2018-03-02

High-speed counter-current chromatography (HSCCC) was used to separate and purify two isoflavones for the first time from Hericium erinaceum ( H. erinaceum ) mycelium using a two-phase solvent system composed of chloroform-dichloromethane-methanol-water (4:2:3:2, v / v / v / v ). These two isoflavones were identified as genistein (4',5,7-trihydroxyisoflavone, C 15 H 10 O₅) and daidzein (4',7-dihydroxyisoflavone, C 15 H 10 O₄), using infrared spectroscopy (IR), electro-spary ionisation mass (ESI-MS), ¹H-nuclear magnetic resonance (NMR) and 13 C-NMR spectra. About 23 mg genistein with 95.7% purity and 18 mg daidzein with 97.3% purity were isolated from 150 mg ethanolic extract of H. erinaceum mycelium. The results demonstrated that HSCCC was a feasible method to separate and purify genistein and daidzein from H. erinaceum mycelium.

Electro-thermal analysis of contact resistance

NASA Astrophysics Data System (ADS)

Pandey, Nitin; Jain, Ishant; Reddy, Sudhakar; Gulhane, Nitin P.

2018-05-01

Electro-Mechanical characterization over copper samples are performed at the macroscopic level to understand the dependence of electrical contact resistance and temperature on surface roughness and contact pressure. For two different surface roughness levels of samples, six levels of load are selected and varied to capture the bulk temperature rise and electrical contact resistance. Accordingly, the copper samples are modelled and analysed using COMSOLTM as a simulation package and the results are validated by the experiments. The interface temperature during simulation is obtained using Mikic-Elastic correlation and by directly entering experimental contact resistance value. The load values are varied and then reversed in a similar fashion to capture the hysteresis losses. The governing equations & assumptions underlying these models and their significance are examined & possible justification for the observed variations are discussed. Equivalent Greenwood model is also predicted by mapping the results of the experiment.

Transmission analysis for OFDM signals over hybrid RF-optical high-throughput satellite.

PubMed

Kolev, Dimitar R; Toyoshima, Morio

2018-02-19

In this paper, a theoretical investigation of the performance of a communication scenario where a geostationary-orbit satellite provides radio-frequency broadband access to the users through orthogonal-frequency-division multiplexing technology and has an optical feeder link is presented. The interface between the radio frequency and the optical parts is achieved by using radio-on-fiber technology for optical-electro and electro-optical conversion onboard and no further signal processing is required. The proposed scheme has significant potential, but presents limitations related to the noise. The noise in both forward and reverse links is described, and the system performance for an example scenario with 1280 MHz bandwidth for QPSK, 16QAM, and 64QAM subcarrier modulation is estimated. The obtained results show that under certain conditions regarding link budget and components choice, the proposed solution is feasible.

Large-area multiplexed sensing using MEMS and fiber optics

NASA Astrophysics Data System (ADS)

Miller, Michael B.; Clark, Richard L., Jr.; Bell, Clifton R.; Russler, Patrick M.

2000-06-01

Micro-electro-mechanical (MEMS) technology offers the ability to implement local and independent sensing and actuation functions through the coordinated response of discrete micro-electro-mechanical 'basis function' elements. The small size of micromechanical components coupled with the ability to reduce costs using volume manufacturing techniques opens up significant potential not only in military applications such as flight and engine monitoring and control, but in autonomous vehicle control, smart munitions, airborne reconnaissance, LADAR, missile guidance, and even in intelligent transportation systems and automotive guidance applications. In this program, Luna Innovations is developing a flexible, programmable interface which can be integrated direction with different types of MEMS sensors, and then used to multiplex many sensors ona single optical fiber to provide a unique combination of functions that will allow larger quantities of sensory input with better resolution than ever before possible.

Constructing a LabVIEW-Controlled High-Performance Liquid Chromatography (HPLC) System: An Undergraduate Instrumental Methods Exercise

ERIC Educational Resources Information Center

Smith, Eugene T.; Hill, Marc

2011-01-01

In this laboratory exercise, students develop a LabVIEW-controlled high-performance liquid chromatography system utilizing a data acquisition device, two pumps, a detector, and fraction collector. The programming experience involves a variety of methods for interface communication, including serial control, analog-to-digital conversion, and…

Fabrication of ordered bulk heterojunction organic photovoltaic cells using nanopatterning and electrohydrodynamic spray deposition methods.

PubMed

Park, Sung-Eun; Kim, Sehwan; Kim, Kangmin; Joe, Hang-Eun; Jung, Buyoung; Kim, Eunkyoung; Kim, Woochul; Min, Byung-Kwon; Hwang, Jungho

2012-12-21

Organic photovoltaic cells with an ordered heterojunction (OHJ) active layer are expected to show increased performance. In the study described here, OHJ cells were fabricated using a combination of nanoimprinting and electrohydrodynamic (EHD) spray deposition methods. After an electron donor material was nanoimprinted with a PDMS stamp (valley width: 230 nm, period: 590 nm) duplicated from a Si nanomold, an electron acceptor material was deposited onto the nanoimprinted donor layer using an EHD spray deposition method. The donor-acceptor interface layer was observed by obtaining cross-sectional images with a focused ion beam (FIB) microscope. The photocurrent generation performance of the OHJ cells was evaluated with the current density-voltage curve under air mass (AM) 1.5 conditions. It was found that the surface morphology of the electron acceptor layer affected the current and voltage outputs of the photovoltaic cells. When an electron acceptor layer with a smooth thin (250 nm above the valley of the electron donor layer) surface morphology was obtained, power conversion efficiency was as high as 0.55%. The electrohydrodynamic spray deposition method used to produce OHJ photovoltaic cells provides a means for the adoption of large area, high throughput processes.

Enhanced Quality Factor Label-free Biosensing with Micro-Cantilevers Integrated into Microfluidic Systems.

PubMed

Kartanas, Tadas; Ostanin, Victor; Challa, Pavan Kumar; Daly, Ronan; Charmet, Jerome; Knowles, Tuomas P J

2017-11-21

Microelectromechanical systems (MEMS) have enabled the development of a new generation of sensor platforms. Acoustic sensor operation in liquid, the native environment of biomolecules, causes, however, significant degradation of sensing performance due to viscous drag and relies on the availability of capture molecules to bind analytes of interest to the sensor surface. Here, we describe a strategy to interface MEMS sensors with microfluidic platforms through an aerosol spray. Our sensing platform comprises a microfluidic spray nozzle and a microcantilever array operated in dynamic mode within a closed loop oscillator. A solution containing the analyte is sprayed uniformly through picoliter droplets onto the microcantilever surface; the micrometer-scale drops evaporate rapidly and leave the solutes behind, adding to the mass of the cantilever. This sensing scheme results in a 50-fold increase in the quality factor compared to operation in liquid, yet allows the analytes to be introduced into the sensing system from a solution phase. It achieves a 370 femtogram limit of detection, and we demonstrate quantitative label-free analysis of inorganic salts and model proteins. These results demonstrate that the standard resolution limits of cantilever sensing in dynamic mode can be overcome with the integration of spray microfluidics with MEMS.

Atomization of a High Speed Jet

NASA Astrophysics Data System (ADS)

Xu, Zhiliang; Samulyak, Roman; Li, Xiaolin; Tzanos, Constantine

2005-11-01

We present a numerical study of the jet breakup and spray formation in a diesel engine by the Front Tracking method. The mechanisms of jet breakup and spray formation of a high speed diesel jet injected through a circular nozzle are the key to design a fuel efficient, nonpolluting diesel engine. Many parameters such as the nuzzle shape, the velocity and the turbulence of the jet and the thermodynamic states of liquid and gas could be contributing causes for jet breakup. We conduct the simulations for the jet breakup within a 2D axis-symmetric geometry. Our goal is to model the spray at a micro-physical level, with the creation of individual droplets. The problem is multiscale. The droplets are a few microns in size. The nozzle is about 0.2 mm in diameter and 1 mm in length. In order to resolve various physical patterns such as vortex, shock waves, vacuum and track droplets and spray, the Burger-Colella adaptive mesh refinement technique is used. We model mixed vapor-liquid region through a heterogeneous model with dynamic vapor bubble insertion. On the liquid/vapor interface, a phase transition problem is solved numerically.

Assessing sea wave and spray effects on Marine Boundary Layer structure

NASA Astrophysics Data System (ADS)

Stathopoulos, Christos; Galanis, George; Patlakas, Platon; Kallos, George

2017-04-01

Air sea interface is characterized by several mechanical and thermodynamical processes. Heat, moisture and momentum exchanges increase the complexity in modeling the atmospheric-ocean system. Near surface atmospheric levels are subject to sea surface roughness and sea spray. Sea spray fluxes can affect atmospheric stability and induce microphysical processes such as sea salt particle formation and condensation/evaporation of water in the boundary layer. Moreover, presence of sea spray can alter stratification over the ocean surface with further insertion of water vapor. This can lead to modified stability conditions and to wind profiles that deviate significantly from the logarithmic approximation. To model these effects, we introduce a fully coupled system consisting of the mesoscale atmospheric model RAMS/ICLAMS and the wave model WAM. The system encompasses schemes for ocean surface roughness, sea salt aerosols and droplet thermodynamic processes and handles sea salt as predictive quantity. Numerical experiments using the developed atmospheric-ocean system are performed over the Atlantic and Mediterranean shoreline. Emphasis is given to the quantification of the improvement obtained in the description of the marine boundary layer, particularly in its lower part as well as in wave characteristics.

Cold spraying SiC/Al metal matrix composites: effects of SiC contents and heat treatment on microstructure, thermophysical and flexural properties

NASA Astrophysics Data System (ADS)

Gyansah, L.; Tariq, N. H.; Tang, J. R.; Qiu, X.; Feng, B.; Huang, J.; Du, H.; Wang, J. Q.; Xiong, T. Y.

2018-02-01

In this paper, cold spray was used as an additive manufacturing method to fabricate 5 mm thick SiC/Al metal matrix composites with various SiC contents. The effects of SiC contents and heat treatment on the microstructure, thermophysical and flexural properties were investigated. Additionally, the composites were characterized for retention of SiC particulates, splat size, surface roughness and the progressive understanding of strengthening, toughening and cracking mechanisms. Mechanical properties were investigated via three-point bending test, thermophysical analysis, and hardness test. In the as-sprayed state, flexural strength increased from 95.3 MPa to 133.5 MPa, an appreciation of 40% as the SiC contents increased, and the main toughening and strengthening mechanisms were zigzag crack propagation and high retention of SiC particulates respectively. In the heat treatment conditions, flexural strength appreciated significantly compared to the as-sprayed condition and this was as a result of coarsening of pure Al splat. Crack branching, crack deflection and interface delamination were considered as the main toughening mechanisms at the heat treatment conditions. Experimental results were consistent with the measured CTE, hardness, porosity and flexural modulus.

Cold Gas-Sprayed Deposition of Metallic Coatings onto Ceramic Substrates Using Laser Surface Texturing Pre-treatment

NASA Astrophysics Data System (ADS)

Kromer, R.; Danlos, Y.; Costil, S.

2018-04-01

Cold spraying enables a variety of metals dense coatings onto metal surfaces. Supersonic gas jet accelerates particles which undergo with the substrate plastic deformation. Different bonding mechanisms can be created depending on the materials. The particle-substrate contact time, contact temperature and contact area upon impact are the parameters influencing physicochemical and mechanical bonds. The resultant bonding arose from plastic deformation of the particle and substrate and temperature increasing at the interface. The objective was to create specific topography to enable metallic particle adhesion onto ceramic substrates. Ceramic did not demonstrate deformation during the impact which minimized the intimate bonds. Laser surface texturing was hence used as prior surface treatment to create specific topography and to enable mechanical anchoring. Particle compressive states were necessary to build up coating. The coating deposition efficiency and adhesion strength were evaluated. Textured surface is required to obtain strong adhesion of metallic coatings onto ceramic substrates. Consequently, cold spray coating parameters depend on the target material and a methodology was established with particle parameters (diameters, velocities, temperatures) and particle/substrate properties to adapt the surface topography. Laser surface texturing is a promising tool to increase the cold spraying applications.

Neutron reflectivity measurement of protein A-antibody complex at the solid-liquid interface.

PubMed

Mazzer, Alice R; Clifton, Luke A; Perevozchikova, Tatiana; Butler, Paul D; Roberts, Christopher J; Bracewell, Daniel G

2017-05-26

Chromatography is a ubiquitous unit operation in the purification of biopharmaceuticals yet few studies have addressed the biophysical characterisation of proteins at the solution-resin interface. Chromatography and other adsorption and desorption processes have been shown to induce protein aggregation which is undesirable in biopharmaceutical products. In order to advance understanding of how adsorption processes might impact protein stability, neutron reflectivity was used to characterise the structure of adsorbed immunoglobulin G (IgG) on model surfaces. In the first model system, IgG was adsorbed directly to silica and demonstrated a side-on orientation with high surface contact. A maximum dimension of 60Å in the surface normal direction and high density surface coverage were observed under pH 4.1 conditions. In chromatography buffers, pH was found to influence IgG packing density and orientation at the solid-liquid interface. In the second model system, which was designed to mimic an affinity chromatography surface, protein A was attached to a silica surface to produce a configuration representative of a porous glass chromatography resin. Interfacial structure was probed during sequential stages from ligand attachment, through to IgG binding and elution. Adsorbed IgG structures extended up to 250Å away from the surface and showed dependence on surface blocking strategies. The data was suggestive of two IgG molecules bound to protein A with a somewhat skewed orientation and close proximity to the silica surface. The findings provide insight into the orientation of adsorbed antibody structures under conditions encountered during chromatographic separations. Copyright © 2017 The Author(s). Published by Elsevier B.V. All rights reserved.

Embedded optical interconnect technology in data storage systems

NASA Astrophysics Data System (ADS)

Pitwon, Richard C. A.; Hopkins, Ken; Milward, Dave; Muggeridge, Malcolm

2010-05-01

As both data storage interconnect speeds increase and form factors in hard disk drive technologies continue to shrink, the density of printed channels on the storage array midplane goes up. The dominant interconnect protocol on storage array midplanes is expected to increase to 12 Gb/s by 2012 thereby exacerbating the performance bottleneck in future digital data storage systems. The design challenges inherent to modern data storage systems are discussed and an embedded optical infrastructure proposed to mitigate this bottleneck. The proposed solution is based on the deployment of an electro-optical printed circuit board and active interconnect technology. The connection architecture adopted would allow for electronic line cards with active optical edge connectors to be plugged into and unplugged from a passive electro-optical midplane with embedded polymeric waveguides. A demonstration platform has been developed to assess the viability of embedded electro-optical midplane technology in dense data storage systems and successfully demonstrated at 10.3 Gb/s. Active connectors incorporate optical transceiver interfaces operating at 850 nm and are connected in an in-plane coupling configuration to the embedded waveguides in the midplane. In addition a novel method of passively aligning and assembling passive optical devices to embedded polymer waveguide arrays has also been demonstrated.

String flash-boiling in gasoline direct injection simulations with transient needle motion

DOE PAGES

Baldwin, Eli T.; Grover, Jr., Ronald O.; Parrish, Scott E.; ...

2016-09-06

A computational study was performed to investigate the influence of transient needle motion on gasoline direct injection (GDI) internal nozzle flow and near-field sprays. Simulations were conducted with a compressible Eulerian flow solver modeling liquid, vapor, and non-condensable gas phases with a diffuse interface. Variable rate generation and condensation of fuel vapor were captured using the homogeneous relaxation model (HRM). The non-flashing (spray G) and flashing (spray G2) conditions specified by the Engine Combustion Network were modeled using the nominal spray G nozzle geometry and transient needle lift and wobble were based upon ensemble averaged x-ray imaging preformed at Argonnemore » National Lab. The minimum needle lift simulated was 5 μm and dynamic mesh motion was achieved with Laplacian smoothing. The results were qualitatively validated against experimental imaging and the experimental rate of injection profile was captured accurately using pressure boundary conditions and needle motion to actu- ate the injection. Needle wobble was found to have no measurable effect on the flow. Low needle lift is shown to result in vapor generation as fuel rushes past the needle. In conclusion, the internal injector flow is shown to contain many transient and interacting vortices which cause perturbations in the spray angle, fluctuations in the mass flux, and frequently result in string flash-boiling.« less

A deep look into the spray coating process in real-time—the crucial role of x-rays

NASA Astrophysics Data System (ADS)

Roth, Stephan V.

2016-10-01

Tailoring functional thin films and coating by rapid solvent-based processes is the basis for the fabrication of large scale high-end applications in nanotechnology. Due to solvent loss of the solution or dispersion inherent in the installation of functional thin films and multilayers the spraying and drying processes are strongly governed by non-equilibrium kinetics, often passing through transient states, until the final structure is installed. Therefore, the challenge is to observe the structural build-up during these coating processes in a spatially and time-resolved manner on multiple time and length scales, from the nanostructure to macroscopic length scales. During installation, the interaction of solid-fluid interfaces and between the different layers, the flow and evaporation themselves determine the structure of the coating. Advanced x-ray scattering methods open a powerful pathway for observing the involved processes in situ, from the spray to the coating, and allow for gaining deep insight in the nanostructuring processes. This review first provides an overview over these rapidly evolving methods, with main focus on functional coatings, organic photovoltaics and organic electronics. Secondly the role and decisive advantage of x-rays is outlined. Thirdly, focusing on spray deposition as a rapidly emerging method, recent advances in investigations of spray deposition of functional materials and devices via advanced x-ray scattering methods are presented.

String flash-boiling in gasoline direct injection simulations with transient needle motion

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

Baldwin, Eli T.; Grover, Jr., Ronald O.; Parrish, Scott E.

A computational study was performed to investigate the influence of transient needle motion on gasoline direct injection (GDI) internal nozzle flow and near-field sprays. Simulations were conducted with a compressible Eulerian flow solver modeling liquid, vapor, and non-condensable gas phases with a diffuse interface. Variable rate generation and condensation of fuel vapor were captured using the homogeneous relaxation model (HRM). The non-flashing (spray G) and flashing (spray G2) conditions specified by the Engine Combustion Network were modeled using the nominal spray G nozzle geometry and transient needle lift and wobble were based upon ensemble averaged x-ray imaging preformed at Argonnemore » National Lab. The minimum needle lift simulated was 5 μm and dynamic mesh motion was achieved with Laplacian smoothing. The results were qualitatively validated against experimental imaging and the experimental rate of injection profile was captured accurately using pressure boundary conditions and needle motion to actu- ate the injection. Needle wobble was found to have no measurable effect on the flow. Low needle lift is shown to result in vapor generation as fuel rushes past the needle. In conclusion, the internal injector flow is shown to contain many transient and interacting vortices which cause perturbations in the spray angle, fluctuations in the mass flux, and frequently result in string flash-boiling.« less

Numerical study on the impacts of the bogus data assimilation and sea spray parameterization on typhoon ducts

NASA Astrophysics Data System (ADS)

Fei, Jianfang; Ding, Juli; Huang, Xiaogang; Cheng, Xiaoping; Hu, Xiaohua

2013-06-01

The Weather Research and Forecasting model version 3.2 (WRF v3.2) was used with the bogus data assimilation (BDA) scheme and sea spray parameterization (SSP), and experiments were conducted to assess the impacts of the BDA and SSP on prediction of the typhoon ducting process induced by Typhoon Mindule (2004). The global positioning system (GPS) dropsonde observations were used for comparison. The results show that typhoon ducts are likely to form in every direction around the typhoon center, with the main type of ducts being elevated duct. With the BDA scheme included in the model initialization, the model has a better performance in predicting the existence, distribution, and strength of typhoon ducts. This improvement is attributed to the positive effect of the BDA scheme on the typhoon's ambient boundary layer structure. Sea spray affects typhoon ducts mainly by changing the latent heat (LH) flux at the air-sea interface beyond 270 km from the typhoon center. The strength of the typhoon duct is enhanced when the boundary layer under this duct is cooled and moistened by the sea spray; otherwise, the typhoon duct is weakened. The sea spray induced changes in the air-sea sensible heat (SH) flux and LH flux are concentrated in the maximum wind speed area near the typhoon center, and the changes are significantly weakened with the increase of the radial range.

Differential wide temperature range CMOS interface circuit for capacitive MEMS pressure sensors.

PubMed

Wang, Yucai; Chodavarapu, Vamsy P

2015-02-12

We describe a Complementary Metal-Oxide Semiconductor (CMOS) differential interface circuit for capacitive Micro-Electro-Mechanical Systems (MEMS) pressure sensors that is functional over a wide temperature range between -55 °C and 225 °C. The circuit is implemented using IBM 0.13 μm CMOS technology with 2.5 V power supply. A constant-gm biasing technique is used to mitigate performance degradation at high temperatures. The circuit offers the flexibility to interface with MEMS sensors with a wide range of the steady-state capacitance values from 0.5 pF to 10 pF. Simulation results show that the circuitry has excellent linearity and stability over the wide temperature range. Experimental results confirm that the temperature effects on the circuitry are small, with an overall linearity error around 2%.

Differential Wide Temperature Range CMOS Interface Circuit for Capacitive MEMS Pressure Sensors

PubMed Central

Wang, Yucai; Chodavarapu, Vamsy P.

2015-01-01

We describe a Complementary Metal-Oxide Semiconductor (CMOS) differential interface circuit for capacitive Micro-Electro-Mechanical Systems (MEMS) pressure sensors that is functional over a wide temperature range between −55 °C and 225 °C. The circuit is implemented using IBM 0.13 μm CMOS technology with 2.5 V power supply. A constant-gm biasing technique is used to mitigate performance degradation at high temperatures. The circuit offers the flexibility to interface with MEMS sensors with a wide range of the steady-state capacitance values from 0.5 pF to 10 pF. Simulation results show that the circuitry has excellent linearity and stability over the wide temperature range. Experimental results confirm that the temperature effects on the circuitry are small, with an overall linearity error around 2%. PMID:25686312

Sensors with centroid-based common sensing scheme and their multiplexing

NASA Astrophysics Data System (ADS)

Berkcan, Ertugrul; Tiemann, Jerome J.; Brooksby, Glen W.

1993-03-01

The ability to multiplex sensors with different measurands but with a common sensing scheme is of importance in aircraft and aircraft engine applications; this unification of the sensors into a common interface has major implications for weight, cost, and reliability. A new class of sensors based on a common sensing scheme and their E/O Interface has been developed. The approach detects the location of the centroid of a beam of light; the set of fiber optic sensors with this sensing scheme include linear and rotary position, temperature, pressure, as well as duct Mach number. The sensing scheme provides immunity to intensity variations of the source or due to environmental effects on the fiber. A detector spatially multiplexed common electro-optic interface for the sensors has been demonstrated with a position and a temperature sensor.

Evaluation of microbeads of calcium alginate as a fluidized bed medium for affinity chromatography of Aspergillus niger Pectinase.

PubMed

Roy, Ipsita; Jain, Sulakshana; Teotia, Sunita; Gupta, Munishwar Nath

2004-01-01

Calcium alginate microbeads (212-425 microm) were prepared by spraying 2% (w/v) alginate solution into 1 M CaCl2 solution. The fluidization behavior of these beads was studied, and the bed expansion index and terminal velocity were found to be 4.3 and 1808 cm h(-1), respectively. Residence time distribution curves showed that the dispersion of the protein was much less with these microbeads than with conventionally prepared calcium alginate macrobeads when both kinds of beads were used for chromatography in a fluidized bed format. The fluidized bed of these beads was used for the purification of pectinase from a commercial preparation. The media performed well even with diluted feedstock; 90% activity recovery with 211-fold purification was observed.

Optical Fluorescence Microscopy for Spatially Characterizing Electron Transfer across a Solid-Liquid Interface on Heterogeneous Electrodes.

PubMed

Choudhary, Eric; Velmurugan, Jeyavel; Marr, James M; Liddle, James A; Szalai, Veronika

2016-01-01

Heterogeneous catalytic materials and electrodes are used for (electro)chemical transformations, including those important for energy storage and utilization. 1, 2 Due to the heterogeneous nature of these materials, activity measurements with sufficient spatial resolution are needed to obtain structure/activity correlations across the different surface features (exposed facets, step edges, lattice defects, grain boundaries, etc.). These measurements will help lead to an understanding of the underlying reaction mechanisms and enable engineering of more active materials. Because (electro)catalytic surfaces restructure with changing environments, 1 it is important to perform measurements in operando . Sub-diffraction fluorescence microscopy is well suited for these requirements because it can operate in solution with resolution down to a few nm. We have applied sub-diffraction fluorescence microscopy to a thin cell containing an electrocatalyst and a solution containing the redox sensitive dye p-aminophenyl fluorescein to characterize reaction at the solid-liquid interface. Our chosen dye switches between a nonfluorescent reduced state and a one-electron oxidized bright state, a process that occurs at the electrode surface. This scheme is used to investigate the activity differences on the surface of polycrystalline Pt, in particular to differentiate reactivity at grain faces and grain boundaries. Ultimately, this method will be extended to study other dye systems and electrode materials.

Electro-encephalogram based brain-computer interface: improved performance by mental practice and concentration skills.

PubMed

Mahmoudi, Babak; Erfanian, Abbas

2006-11-01

Mental imagination is the essential part of the most EEG-based communication systems. Thus, the quality of mental rehearsal, the degree of imagined effort, and mind controllability should have a major effect on the performance of electro-encephalogram (EEG) based brain-computer interface (BCI). It is now well established that mental practice using motor imagery improves motor skills. The effects of mental practice on motor skill learning are the result of practice on central motor programming. According to this view, it seems logical that mental practice should modify the neuronal activity in the primary sensorimotor areas and consequently change the performance of EEG-based BCI. For developing a practical BCI system, recognizing the resting state with eyes opened and the imagined voluntary movement is important. For this purpose, the mind should be able to focus on a single goal for a period of time, without deviation to another context. In this work, we are going to examine the role of mental practice and concentration skills on the EEG control during imaginative hand movements. The results show that the mental practice and concentration can generally improve the classification accuracy of the EEG patterns. It is found that mental training has a significant effect on the classification accuracy over the primary motor cortex and frontal area.

Design and analytical modeling of magneto-electro-mechanical characteristics of a novel magneto-electro-elastic vibration-based energy harvesting system

NASA Astrophysics Data System (ADS)

Shishesaz, Mohammad; Shirbani, Meisam Moory; Sedighi, Hamid Mohammad; Hajnayeb, Ali

2018-07-01

In order to effectively design an energy harvesting system for any specific application, a model that accurately characterizes the energy harvesting parameters is needed. In the present paper a novel magneto-electro-elastic (MEE) cantilever beam has been proposed and modeled as an effective means to increase the harvested electrical power in a vibration-based energy harvesting system. The cantilever beam is composed of a linear homogeneous elastic substrate and two MEE layers with perfect bonds between their interfaces. Using the constitutive equations, Gauss's and Faraday's laws, based on the Euler-Bernoulli beam theory, the coupled magneto-electro-mechanical (MeM) differential equations are derived for a harmonic base excitation in the transversal direction with a superimposed small rotation. The resulting equations are then solved analytically to obtain the dynamic behavior as well as the harvested voltages and powers of the proposed energy harvesting system. Finally, parametric numerical studies are used to examine the effect of excitation frequency, external resistive loads, and material properties on the performance of the MEE energy harvester. The study reveals that the implementation of the coil circuit has resulted in an increase in the total useful harvested power. According to the numerical results, any increase in the Young's modulus and density of the substrate layer (across the ranges that have been studied and while the properties of the MEE layer are kept constant), increases the magnitude of the magnetoelectric harvested power in the unimorph MEE energy harvester system.

Electro membrane extraction of sodium diclofenac as an acidic compound from wastewater, urine, bovine milk, and plasma samples and quantification by high-performance liquid chromatography.

PubMed

Davarani, Saied Saeed Hosseiny; Pourahadi, Ahmad; Nojavan, Saeed; Banitaba, Mohammad Hossein; Nasiri-Aghdam, Mahnaz

2012-04-13

Electro membrane extraction (EME) as a new microextraction method was applied for extraction of sodium diclofenac (SDF) as an acidic compound from wastewater, urine, bovine milk and plasma samples. Under applied potential of 20 V during the extraction, SDF migrated from a 2.1 mL of sample solution (1mM NaOH), through a supported liquid membrane (SLM), into a 30 μL acceptor solution (10 mM NaOH), exist inside the lumen of the hollow fiber. The negative electrode was placed in the donor solution, and the positive electrode was placed in the acceptor solution. 1-octanol was immobilized in the pores of a porous hollow fiber of polypropylene as SLM. Then the extract was analyzed by means of high-performance liquid chromatography (HPLC) with UV-detection for quantification of SDF. Best results were obtained using a phosphate running electrolyte (10 mM, pH 2.5). The ranges of quantitation for different samples were 8-500 ngmL(-1). Intra- and inter-day RSDs were less than 14.5%. Under the optimized conditions, the preconcentration factors were between 31 and 66 and also the limit of detections (LODs) ranged from 2.7 ng mL(-1) to 5 ng mL(-1) in different samples. This procedure was applied to determine SDF in wastewater, bovine milk, urine and plasma samples (spiked and real samples). Extraction recoveries for different samples were between 44-95% after 5 min of extraction. Copyright © 2012 Elsevier B.V. All rights reserved.

Advances in HPLC-ICP-MS interface techniques for metal speciation

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

Hill, S.J.

The relentless demand for lower detection limits is increasingly coupled to the requirement for elemental speciation. This is particularly true in environmental and clinical fields where total levels are often insufficient for mobility and toxicity studies. This demand for both qualitative and quantitative data on the individual species present in complex samples has led to the development of various interfaces to couple some form of chromatography, usually gas chromatography (GC) or high performance liquid chromatography (HPLC) to an element specific detector. Today inductively coupled plasma-mass spectrometry is often employed since it offers excellent detection limits, element specific information (including isotopicmore » data) and the potential for multi-element studies. Ms presentation will concentrate on HPLC couplings although the advantages and disadvantages of both GC and HPLC couplings to ICP-MS will be discussed. Particular attention will be given to the optimization of both the chromatography and detection systems. Details will be presented of several successful HPLC interface designs and ways of facilitating high levels of a range of organic solvents (e.g. methanol and THF) in the HPLC mobile phase will be highlighted. The advantages of using a sheath gas and practical ways of achieving this will also be discussed. Finally the use of isotope dilution analysis in conjunction with HPLC-ICP-MS will be outlined. In all cases the impact of using the most appropriate approach will be demonstrated using both environmental and clinical samples.« less

Corona Discharge Suppression in Negative Ion Mode Nanoelectrospray Ionization via Trifluoroethanol Addition.

PubMed

McClory, Phillip J; Håkansson, Kristina

2017-10-03

Negative ion mode nanoelectrospray ionization (nESI) is often utilized to analyze acidic compounds, from small molecules to proteins, with mass spectrometry (MS). Under high aqueous solvent conditions, corona discharge is commonly observed at emitter tips, resulting in low ion abundances and reduced nESI needle lifetimes. We have successfully reduced corona discharge in negative ion mode by trace addition of trifluoroethanol (TFE) to aqueous samples. The addition of as little as 0.2% TFE increases aqueous spray stability not only in nESI direct infusion, but also in nanoflow liquid chromatography (nLC)/MS experiments. Negative ion mode spray stability with 0.2% TFE is approximately 6× higher than for strictly aqueous samples. Upon addition of 0.2% TFE to the mobile phase of nLC/MS experiments, tryptic peptide identifications increased from 93 to 111 peptides, resulting in an average protein sequence coverage increase of 18%.

A H2-evolving photocathode based on direct sensitization of MoS3 with an organic photovoltaic cell

PubMed Central

Bourgeteau, Tiphaine; Tondelier, Denis; Geffroy, Bernard; Brisse, Romain; Laberty-Robert, Christel; Campidelli, Stéphane; de Bettignies, Rémi; Artero, Vincent; Palacin, Serge; Jousselme, Bruno

2013-01-01

An organic solar cell based on a poly-3-hexylthiophene (P3HT): phenyl-C61-butyric acid (PCBM) bulk hetero-junction was directly coupled with molybdenum sulfide resulting in the design of a new type of photocathode for the production of hydrogen. Both the light-harvesting system and the catalyst were deposited by low-cost solution-processed methods, i.e. spin coating and spray coating respectively. Spray-coated MoS3 films are catalytically active in strongly acidic aqueous solutions with the best efficiencies for thicknesses of 40 to 90 nm. The photocathodes display photocurrents higher than reference samples, without catalyst or without coupling with a solar cell. Analysis by gas chromatography confirms the light-induced hydrogen evolution. The addition of titanium dioxide in the MoS3 film enhances electron transport and collection within thick films and therefore the performance of the photocathode. PMID:24404434

Persistence of Azoxystrobin in/on Grapes and Soil in Different Grapes Growing Areas of India

PubMed Central

Gajbhiye, Vijay Tularam; Gupta, Suman; Mukherjee, Irani; Singh, Shashi Bala; Singh, Neera; Kumar, Yogesh

2010-01-01

Persistence of azoxystrobin was studied in/on grapes when applied @ 150 g ai ha−1 (recommended dose) and 300 g ai ha−1 (double the recommended dose) in three grapes growing states of India, namely Karnataka, Maharashtra and Tamil Nadu, in the year 2006–2007. A total of five sprays were given at an interval of about 15 days. Grapes and soil samples were collected after 5th spray, extracted and analysed by gas chromatography using electron capture detector. Half life of azoxystrobin on grapes varied from 5.4 to 11.2 days. Residues of azoxystrobin were much below the prescribed MRL (0.5 mg kg−1) after 21 days. The dissipation of azoxystrobin in soil followed first order rate kinetics with an average half life of 8.1 days at the recommended dose of application. PMID:21153804

Detection of amines with extended distyrylbenzenes by strip assays.

PubMed

Kumpf, Jan; Freudenberg, Jan; Fletcher, Katharyn; Dreuw, Andreas; Bunz, Uwe H F

2014-07-18

We herein describe the synthesis and property evaluation of three novel aldehyde-substituted pentameric phenylenevinylenes carrying branched oligo(ethylene glycol) (swallowtail, Sw) substituents. The targets were synthesized by a combination of Heck coupling and Wittig or Horner reactions of suitable precursor modules. If the pentameric phenylenevinylene carries only two of these Sw substituents, it is no longer water-soluble. When six of the Sw substituents are attached, regardless of their position, the pentameric phenylenevinylenes are well water-soluble. The dialdehydes were investigated with respect to their amine-sensing capabilities both in water as well as in the solid state, sprayed onto thin layer chromatography (TLC) plates (alox, silica gel, reversed phase silica gel). The recognition of amine vapors using the sprayed-on phenylenevinylene dialdehydes is superb and allows the identification of different amines on regular silica TLC plates via color changes, analyzed by a statistical tool, the multivariate analysis of variance (MANOVA) protocol.

Novel Method of Aluminum to Copper Bonding by Cold Spray

NASA Astrophysics Data System (ADS)

Fu, Si-Lin; Li, Cheng-Xin; Wei, Ying-Kang; Luo, Xiao-Tao; Yang, Guan-Jun; Li, Chang-Jiu; Li, Jing-Long

2018-04-01

Cold spray bonding (CSB) has been proposed as a new method for joining aluminum and copper. At high speeds, solid Al particles impacted the groove between the two substrates to form a bond between Al and Cu. Compared to traditional welding technologies, CSB does not form distinct intermetallic compounds. Large stainless steel particles were introduced into the spray powders as in situ shot peen particles to create a dense Al deposit and to improve the bond strength of joints. It was discovered that introducing shot peen particles significantly improved the flattening ratio of the deposited Al particles. Increasing the proportion of shot peen particles from 0 to 70 vol.% decreased the porosity of the deposits from 12.4 to 0.2%, while the shear strength of joints significantly increased. The tensile test results of the Al-Cu joints demonstrated that cracks were initiated at the interface between the Al and the deposit. The average tensile strength was 71.4 MPa and could reach 81% of the tensile strength of pure Al.

Enhancement of low pressure cold sprayed copper coating adhesion by laser texturing on aluminum substrates

NASA Astrophysics Data System (ADS)

Knapp, Wolfgang; Gillet, Vincent; Courant, Bruno; Aubignat, Emilie; Costil, Sophie; Langlade, Cécile

2017-02-01

Surface pre-treatment is fundamental in thermal spraying processes to obtain a sufficient bonding strength between substrate and coating. Different pre-treatments can be used, mostly grit-blasting for current industrial applications. This study is focused on Cu-Al2O3 coatings obtained by Low Pressure Cold Spray on AW5083 aluminum alloy substrate. Bonding strength is measured by tensile adhesion test, while deposition efficiency is measured. Substrates are textured by laser, using a pattern of equally spaced grooves with almost constant diameter and variations of depth. Results show that bonding strength is improved up to +81% compared to non-treated substrate, while deposition efficiency remains constant. The study of the samples after rupture reveals a modification of the failure mode, from mixed failure to cohesive failure. A modification of crack propagation is also noticed, the shape of laser textured grooves induces a deviation of cracks inside the coating instead of following the interface between the layers.

Development of a multiplexed electrospray micro-thruster with post-acceleration and beam containment

NASA Astrophysics Data System (ADS)

Lenguito, G.; Gomez, A.

2013-10-01

We report the development of a compact thruster based on Multiplexed ElectroSprays (MES). It relied on a microfabricated Si array of emitters coupled with an extractor electrode and an accelerator electrode. The accelerator stage was introduced for two purposes: containing beam opening and avoiding electrode erosion due to droplet impingement, as well as boosting specific impulse and thrust. Multiplexing is generally necessary as a thrust multiplier to reach eventually the level required (O(102) μN) by small satellites. To facilitate system optimization and debugging, we focused on a 7-nozzle MES device and compared its performance to that of a single emitter. To ensure uniformity of operation of all nozzles their hydraulic impedance was augmented by packing them with micrometer-size beads. Two propellants were tested: a solution of 21.5% methyl ammonium formate in formamide and the better performing pure ionic liquid ethyl ammonium nitrate (EAN). The 7-MES device spraying EAN at ΔV = 5.93 kV covered a specific impulse range from 620 s to 1900 s and a thrust range from 0.6 μN to 5.4 μN, at 62% efficiency. Remarkably, less than 1% of the beam was demonstrated to impact on the accelerator electrode, which bodes well for long-term applications in space.

Electro-optical processing of phased array data

NASA Technical Reports Server (NTRS)

Casasent, D.

1973-01-01

An on-line spatial light modulator for application as the input transducer for a real-time optical data processing system is described. The use of such a device in the analysis and processing of radar data in real time is reported. An interface from the optical processor to a control digital computer was designed, constructed, and tested. The input transducer, optical system, and computer interface have been operated in real time with real time radar data with the input data returns recorded on the input crystal, processed by the optical system, and the output plane pattern digitized, thresholded, and outputted to a display and storage in the computer memory. The correlation of theoretical and experimental results is discussed.

Role of carbon nanotube dispersion in fracture toughening of plasma sprayed aluminum oxide-carbon nanotube nanocomposite coating

NASA Astrophysics Data System (ADS)

Balani, Kantesh

Aluminum oxide (Al2O3, or alumina) is a conventional ceramic known for applications such as wear resistant coatings, thermal liners, heaters, crucibles, dielectric systems, etc. However applications of Al 2O3 are limited owing to its inherent brittleness. Due to its excellent mechanical properties and bending strength, carbon nanotubes (CNT) is an ideal reinforcement for Al2O3 matrix to improve its fracture toughness. The role of CNT dispersion in the fracture toughening of the plasma sprayed Al2O3-CNT nanocomposite coating is discussed in the current work. Pretreatment of powder feedstock is required for dispersing CNTs in the matrix. Four coatings namely spray dried Al2O 3 (A-SD), Al2O3 blended with 4wt.% CNT (A4C-B), composite spray dried Al2O3-4wt.% CNT (A4C-SD) and composite spray dried A1203-8wt.% CNT (A8C-SD), are synthesized by plasma spraying. Owing to extreme temperatures and velocities involved in the plasma spraying of ceramics, retention of CNTs in the resulting coatings necessitates optimizing plasma processing parameters using an inflight particle diagnostic sensor. A bimodal microstructure was obtained in the matrix that consists of fully melted and resolidified structure and solid state sintered structure. CNTs are retained both in the fully melted region and solid-state sintered regions of processed coatings. Fracture toughness of A-SD, A4C-B, A4C-SD and A8C-SD coatings was 3.22, 3.86, 4.60 and 5.04 MPa m1/2 respectively. This affirms the improvement of fracture toughness from 20% (in A4C-B coating) to 43% (in A4C-SD coating) when compared to the A-SD coating because of the CNT dispersion. Fracture toughness improvement from 43% (in A4C-SD) to 57% (in A8C-SD) coating is evinced because of the CNT content. Reinforcement by CNTs is described by its bridging, anchoring, hook formation, impact alignment, fusion with splat, and mesh formation. The Al2O3/CNT interface is critical in assisting the stress transfer and utilizing excellent mechanical properties of CNTs. Mathematical and computational modeling using ab-initio principle is applied to understand the wetting behavior at the Al2O 3/CNT interface. Contrasting storage modulus was obtained by nanoindentation (˜210, 250, 250-350 and 325-420 GPa in A-SD, A4C-B, A4C-SD, and A8C-SD coatings respectively) depicting the toughening associated with CNT content and dispersion.

Monitoring binding affinity between drug and α1-acid glycoprotein in real time by Venturi easy ambient sonic-spray ionization mass spectrometry.

PubMed

Liu, Ning; Lu, Xin; Yang, YuHan; Yao, Chen Xi; Ning, BaoMing; He, Dacheng; He, Lan; Ouyang, Jin

2015-10-01

A new approach for monitoring the binding affinity between drugs and alpha 1-acid glycoprotein in real time was developed based on a combination of drug-protein reaction followed by Venturi easy ambient sonic-spray ionization mass spectrometry determination of the free drug concentrations. A known basic drug, propranolol was used to validate the new built method. Binding constant values calculated by venturi easy ambient sonic-spray ionization mass spectrometry was in good accordance with a traditional ultrafiltration combined with high performance liquid chromatography method. Then six types of basic drugs were used as the samples to conduct the real time analysis. Upon injection of alpha 1-acid glycoprotein to the drug mixture, the ion chromatograms were extracted to show the changes in the free drug concentrations in real time. By observing the drop-out of six types of drugs during the whole binding reaction, the binding affinities of different drugs were distinguished. A volume shift validating experiment and an injection delay correcting experiment were also performed to eliminate extraneous factors and verify the reliability of our experiment. Therefore, the features of Venturi easy ambient sonic-spray ionization mass spectrometry (V-EASI-MS) and the experimental results indicate that our technique is likely to become a powerful tool for monitoring drug-AGP binding affinity in real time. Copyright © 2015 Elsevier B.V. All rights reserved.

Electro-optical properties of low viscosity driven holographic polymer dispersed liquid crystals

NASA Astrophysics Data System (ADS)

Moon, K. R.; Bae, S. Y.; Kim, B. K.

2015-04-01

Relative diffraction efficiency (RDE), operating voltage, and response times are most important performance characteristics of holographic polymer dispersed liquid crystals (HPDLC). Two types of triallyl isocyanurate (TI) having different structures were incorporated into the conventional transmission grating of HPDLC. Premix viscosity decreased by 13-18% with up to 3% TI, beyond which it increased. TI eliminated induction period and augmented initial grating formation rate at all contents. Saturation RDE increased over 200% while threshold voltage and rise time decreased to about half and 2/3, respectively up to 3% TI, beyond which the tendencies were reversed. Among the two TIs, low viscosity monomer (TA) showed high RDE, while high miscibility monomer (TE) low characteristic voltages and short response times. It is concluded that grating formation is largely favored by low viscosity, while interface tensions and electro-optical performances by miscibility at similar viscosities.

Evaluation of a Programmable Voltage-Controlled MEMS Oscillator, Type SiT3701, Over a Wide Temperature Range

NASA Technical Reports Server (NTRS)

Patterson, Richard; Hammoud, Ahmad

2009-01-01

Semiconductor chips based on MEMS (Micro-Electro-Mechanical Systems) technology, such as sensors, transducers, and actuators, are becoming widely used in today s electronics due to their high performance, low power consumption, tolerance to shock and vibration, and immunity to electro-static discharge. In addition, the MEMS fabrication process allows for the miniaturization of individual chips as well as the integration of various electronic circuits into one module, such as system-on-a-chip. These measures would simplify overall system design, reduce parts count and interface, improve reliability, and reduce cost; and they would meet requirements of systems destined for use in space exploration missions. In this work, the performance of a recently-developed MEMS voltage-controlled oscillator was evaluated under a wide temperature range. Operation of this new commercial-off-the-shelf (COTS) device was also assessed under thermal cycling to address some operational conditions of the space environment

Multiplexing electro-optic architectures for advanced aircraft integrated flight control systems

NASA Technical Reports Server (NTRS)

Seal, D. W.

1989-01-01

This report describes the results of a 10 month program sponsored by NASA. The objective of this program was to evaluate various optical sensor modulation technologies and to design an optimal Electro-Optic Architecture (EOA) for servicing remote clusters of sensors and actuators in advanced aircraft flight control systems. The EOA's supply optical power to remote sensors and actuators, process the modulated optical signals returned from the sensors, and produce conditioned electrical signals acceptable for use by a digital flight control computer or Vehicle Management System (VMS) computer. This study was part of a multi-year initiative under the Fiber Optic Control System Integration (FOCSI) program to design, develop, and test a totally integrated fiber optic flight/propulsion control system for application to advanced aircraft. Unlike earlier FOCSI studies, this program concentrated on the design of the EOA interface rather than the optical transducer technology itself.

Carbon Nanotube Thermal Interfaces Enhanced with Sprayed on Nanoscale Polymer Coatings

DTIC Science & Technology

2013-02-20

temperature of the growth stage was lowered to 750 ◦C (a pyrometer measured the actual sample temperature to be approximately 630 ◦C, which is less than the...the heat is absorbed at the sample surface it is conducted both downward through the sample and upward into an acoustic chamber filled with He gas. The

Sea-State Dependence of Aerosol Concentration in the Marine Atmospheric Boundary Layer

NASA Astrophysics Data System (ADS)

Lenain, L.; Melville, W. K.

2016-02-01

While sea spray aerosols represent a large portion of the aerosols present in the marine environment, and despite evidence of the importance of surface wave and wave-breaking related processes in the coupling of the ocean with the atmosphere, sea spray source generation functions are traditionally parameterized by the wind speed at 10m. It is clear that unless the wind and wave field are fully developed, the source function will be a function of both wind and wave parameters. In this study, we report on an air-sea interaction experiment, the ONR phase-resolved High-Resolution Air-Sea Interaction experiments (HIRES), conducted off the coast of Northern California in June 2010. Detailed measurements of aerosol number concentration in the Marine Atmospheric Boundary Layer (MABL), at altitudes ranging from as low as 30m and up to 800m AMSL over a broad range of environmental conditions (significant wave height, Hs, of 2 to 4.5m and wind speed at 10m height, U10, of 10 to 18 m/s) collected from an instrumented research aircraft, are presented. Aerosol number densities and volume are computed over a range of particle diameters from 0.1 to 200 µm, while the surface conditions, i.e. significant wave height, moments of the breaker length distribution Λ(c), and wave breaking dissipation, were measured by a suite of electro-optical sensors that included the NASA Airborne Topographic Mapper (ATM). The sea-state dependence of the aerosol concentration in the MABL is evident, ultimately stressing the need to incorporate wave and wave kinematics in the spray source generation functions that are traditionally primarily parameterized by surface winds. A scaling of the measured aerosol volume distribution by wave and atmospheric state variables is proposed.

Technology Assessment: 1983 Forecast of Future Test Technology Requirements.

DTIC Science & Technology

1983-06-01

effectively utilizes existing vehicle space , power and support equipment while maintaining critical interfaces with on-board computers and fire control...Scan Converter EAR Electronically Agile Radar E-O Electro-Optics FET Field Effect Transistor FLIR Forward Looking Infrared GaAs Gallium Arsenide HEL...They might be a part of a large ATE system due to such things as the environmental effects on noise and signal/power loss. A summary of meaningful

Effect of Time and Deposition Method on Quality of Phosphonic Acid Modifier Self-Assembled Monolayers on Indium Zinc Oxide

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

Sang, Lingzi; Knesting, Kristina M.; Bulusu, Anuradha

Phosphonic acid (PA) self-assembled monolayers (SAMs) are utilized at critical interfaces between transparent conductive oxides (TCO) and organic active layers in organic photovoltaic devices (OPVs). The effects of PA deposition method and time on the formation of close-packed, high-quality monolayers is investigated here for SAMs fabricated by solution deposition, micro-contact printing, and spray coating. The solution deposition isotherm for pentafluorinated benzylphosphonic acid (F5BnPA) on indium-doped zinc oxide (IZO) is studied using polarization modulation-infrared reflection-absorption spectroscopy (PM-IRRAS) at room temperature as a model PA/IZO system. Fast surface adsorption occurs within the first min; however, well-oriented high-quality SAMs are reached only aftermore » -48 h, presumably through a continual process of molecular adsorption/desorption and monolayer filling accompanied by molecular reorientation. Two other rapid, soak-free deposition techniques, micro-contact printing and spray coating, are also explored. SAM quality is compared for deposition of phenyl phosphonic acid (PPA), F13-octylphosphonic acid (F13OPA), and pentafluorinated benzyl phosphonic acid (F5BnPA) by solution deposition, micro-contact printing and spray coating using PM-IRRAS. In contrast to micro-contact printing and spray coating techniques, 48-168 h solution deposition at both room temperature and 70 degrees C result in contamination- and surface etch-free close-packed monolayers with good reproducibility. SAMs fabricated by micro-contact printing and spray coating are much less well ordered.« less

Numerical simulation of cavitation and atomization using a fully compressible three-phase model

NASA Astrophysics Data System (ADS)

Mithun, Murali-Girija; Koukouvinis, Phoevos; Gavaises, Manolis

2018-06-01

The aim of this paper is to present a fully compressible three-phase (liquid, vapor, and air) model and its application to the simulation of in-nozzle cavitation effects on liquid atomization. The model employs a combination of the homogeneous equilibrium barotropic cavitation model with an implicit sharp interface capturing volume of fluid (VOF) approximation. The numerical predictions are validated against the experimental results obtained for injection of water into the air from a step nozzle, which is designed to produce asymmetric cavitation along its two sides. Simulations are performed for three injection pressures, corresponding to three different cavitation regimes, referred to as cavitation inception, developing cavitation, and hydraulic flip. Model validation is achieved by qualitative comparison of the cavitation, spray pattern, and spray cone angles. The flow turbulence in this study is resolved using the large-eddy simulation approach. The simulation results indicate that the major parameters that influence the primary atomization are cavitation, liquid turbulence, and, to a smaller extent, the Rayleigh-Taylor and Kelvin-Helmholtz aerodynamic instabilities developing on the liquid-air interface. Moreover, the simulations performed indicate that periodic entrainment of air into the nozzle occurs at intermediate cavitation numbers, corresponding to developing cavitation (as opposed to incipient and fully developed cavitation regimes); this transient effect causes a periodic shedding of the cavitation and air clouds and contributes to improved primary atomization. Finally, the cone angle of the spray is found to increase with increased injection pressure but drops drastically when hydraulic flip occurs, in agreement with the relevant experiments.

Formation of Cr2O3 Diffusion Barrier Between Cr-Contained Stainless Steel and Cold-Sprayed Ni Coatings at High Temperature

NASA Astrophysics Data System (ADS)

Xu, Ya-Xin; Luo, Xiao-Tao; Li, Cheng-Xin; Yang, Guan-Jun; Li, Chang-Jiu

2016-02-01

A novel approach to prepare a coating system containing an in situ grown Cr2O3 diffusion barrier between a nickel top layer and 310SS was reported. Cold spraying was employed to deposit Ni(O) interlayer and top nickel coating on the Cr-contained stainless steel substrate. Ni(O) feedstock was prepared by mechanical alloying of pure nickel powders in ambient atmosphere, acting as an oxygen provider. The post-spray annealing was adopted to grow in situ Cr2O3 layer between the substrate and nickel coating. The results revealed that the diffusible oxygen can be introduced into nickel powders by mechanical alloying. The oxygen content increases to 3.25 wt.% with the increase of the ball milling duration to 8 h, while Ni(O) powders maintain a single phase of Ni. By annealing the sample in Ar atmosphere at 900 °C, a continuous Cr2O3 layer of 1-2 μm thick at the interface between 310SS and cold-sprayed Ni coating is formed. The diffusion barrier effect evaluation by thermal exposure at 750 °C shows that the Cr2O3 oxide layer effectively suppresses the outward diffusion of Fe and Cr in the substrate effectively.

High-power hybrid plasma spraying of large yttria-stabilized zirconia powder

NASA Astrophysics Data System (ADS)

Huang, Heji; Eguchi, Keisuke; Yoshida, Toyonobu

2006-03-01

To testify to the advantage of large ceramic powder spraying, numerical simulations and experimental studies on the behavior of large yttria-stabilized zirconia (YSZ) powder in a high-power hybrid plasma spraying process have been carried out. Numeric predictions and experimental results showed that, with the high radio frequency (RF) input power of 100 kW, the most refractory YSZ powder with particle sizes as large as 88 μm could be fully melted and well-flattened splats could be formed. A large degree of flattening (ξ) of 4.7 has been achieved. The improved adhesive strength between the large splat and the substrate was confirmed based on the measurement of the crack density inside of the splats. A thick YSZ coating >300 μm was successfully deposited on a large CoNiCrAlY-coated Inconel substrate (50×50×4 mm in size). The ultradense microstructure without clear boundaries between the splats and the clean and crack-free interface between the top-coat and the bond-coat also indicate the good adhesion. These results showed that highpower hybrid plasma spraying of large ceramic powder is a very promising process for deposition of highquality coatings, especially in the application of thermal barrier coatings (TBCs).

Lanthanide-Assisted Deposition of Strongly Electro-optic PZT Thin Films on Silicon: Toward Integrated Active Nanophotonic Devices.

PubMed

George, J P; Smet, P F; Botterman, J; Bliznuk, V; Woestenborghs, W; Van Thourhout, D; Neyts, K; Beeckman, J

2015-06-24

The electro-optical properties of lead zirconate titanate (PZT) thin films depend strongly on the quality and crystallographic orientation of the thin films. We demonstrate a novel method to grow highly textured PZT thin films on silicon using the chemical solution deposition (CSD) process. We report the use of ultrathin (5-15 nm) lanthanide (La, Pr, Nd, Sm) based intermediate layers for obtaining preferentially (100) oriented PZT thin films. X-ray diffraction measurements indicate preferentially oriented intermediate Ln2O2CO3 layers providing an excellent lattice match with the PZT thin films grown on top. The XRD and scanning electron microscopy measurements reveal that the annealed layers are dense, uniform, crack-free and highly oriented (>99.8%) without apparent defects or secondary phases. The EDX and HRTEM characterization confirm that the template layers act as an efficient diffusion barrier and form a sharp interface between the substrate and the PZT. The electrical measurements indicate a dielectric constant of ∼650, low dielectric loss of ∼0.02, coercive field of 70 kV/cm, remnant polarization of 25 μC/cm(2), and large breakdown electric field of 1000 kV/cm. Finally, the effective electro-optic coefficients of the films are estimated with a spectroscopic ellipsometer measurement, considering the electric field induced variations in the phase reflectance ratio. The electro-optic measurements reveal excellent linear effective pockels coefficients of 110 to 240 pm/V, which makes the CSD deposited PZT thin film an ideal candidate for Si-based active integrated nanophotonic devices.

Three-dimensional printing-based electro-millifluidic devices for fabricating multi-compartment particles.

PubMed

Chen, Qiu Lan; Liu, Zhou; Shum, Ho Cheung

2014-11-01

In this work, we demonstrate the use of stereolithographic 3D printing to fabricate millifluidic devices, which are used to engineer particles with multiple compartments. As the 3D design is directly transferred to the actual prototype, this method accommodates 3D millimeter-scaled features that are difficult to achieve by either lithographic-based microfabrication or traditional macrofabrication techniques. We exploit this approach to produce millifluidic networks to deliver multiple fluidic components. By taking advantage of the laminar flow, the fluidic components can form liquid jets with distinct patterns, and each pattern has clear boundaries between the liquid phases. Afterwards, droplets with controlled size are fabricated by spraying the liquid jet in an electric field, and subsequently converted to particles after a solidification step. As a demonstration, we fabricate calcium alginate particles with structures of (1) slice-by-slice multiple lamellae, (2) concentric core-shells, and (3) petals surrounding the particle centers. Furthermore, distinct hybrid particles combining two or more of the above structures are also obtained. These compartmentalized particles impart spatially dependent functionalities and properties. To show their applicability, various ingredients, including fruit juices, drugs, and magnetic nanoparticles are encapsulated in the different compartments as proof-of-concepts for applications, including food, drug delivery, and bioassays. Our 3D printed electro-millifluidic approach represents a convenient and robust method to extend the range of structures of functional particles.

Enantioselective analysis of triazole fungicide myclobutanil in cucumber and soil under different application modes by chiral liquid chromatography/tandem mass spectrometry.

PubMed

Dong, Fengshou; Cheng, Li; Liu, Xingang; Xu, Jun; Li, Jing; Li, Yuanbo; Kong, Zhiqiang; Jian, Qiu; Zheng, Yongquan

2012-02-29

A sensitive and enantioselective method was developed and validated for the determination of myclobutanil enantiomers by chiral liquid chromatography coupled with tandem mass spectrometry. The separation and determination were performed using reversed-phase chromatography on a Chiralcel OD-RH column, with ACN-water (70/30, v/v) as the mobile phase under isocratic conditions at 0.5 mL/min flow rate. The matrix effect, linearity, precision, accuracy, and stability were evaluated. The proposed method then was successfully applied to the study of enantioselective degradation of rac-myclobutanil in cucumber and soil under different application modes. The results showed that the preferential degradation of (+)-myclobutanil resulted in an enrichment of the (-)-myclobutanil residue in plant and soil. Moreover, in cucumber, the stereoselective intensity of myclobutanil under root douche treatment was stronger than that under foliar spraying treatment, whereas in soil, the intensity was exactly opposite. The probable reasons underlying these enantioselective effects were also discussed. This study highlighted the importance of examining the fate of both enantiomers in the greenhouse system for the correct use of chiral pesticides.

Multi-scale strategies for dealing with moving contact lines

NASA Astrophysics Data System (ADS)

Smith, Edward R.; Theodorakis, Panagiotis; Craster, Richard V.; Matar, Omar K.

2017-11-01

Molecular dynamics (MD) has great potential to elucidate the dynamics of the moving contact line. As a more fundamental model, it can provide a priori results for fluid-liquid interfaces, surface tension, viscosity, phase change, and near wall stick-slip behaviour which typically show very good agreement to experimental results. However, modelling contact line motion combines all this complexity in a single problem. In this talk, MD simulations of the contact line are compared to the experimental results obtained from studying the dynamics of a sheared liquid bridge. The static contact angles are correctly matched to the experimental data for a range of different electro-wetting results. The moving contact line results are then compared for each of these electro-wetting values. Despite qualitative agreement, there are notable differences between the simulation and experiments. Many MD simulation have studied contact lines, and the sheared liquid bridge, so it is of interest to review the limitations of this setup in light of this discrepancy. A number of factors are discussed, including the inter-molecular interaction model, molecular-scale surface roughness, model of electro-wetting and, perhaps most importantly, the limited system sizes possible using MD simulation. EPSRC, UK, MEMPHIS program Grant (EP/K003976/1), RAEng Research Chair (OKM).

Solidification of Undercooled Melts of Al-Based Alloys on Earth and in Space

NASA Astrophysics Data System (ADS)

Herlach, Dieter M.; Burggraf, Stefan; Galenko, Peter; Gandin, Charles-André; Garcia-Escorial, Asuncion; Henein, Hani; Karrasch, Christian; Mullis, Andrew; Rettenmayr, Markus; Valloton, Jonas

2017-08-01

Containerless processing of droplets and drops by atomization and electromagnetic levitation are applied to undercool metallic melts and alloys prior to solidification. Heterogeneous nucleation on crucible walls is completely avoided giving access to large undercoolings. Experiments are performed both under terrestrial (1 g) conditions and in reduced gravity ( µg) as well. Microgravity conditions are realized by the free fall of small droplets during atomization of a spray of droplets, individual drops in a drop tube and by electromagnetic levitation of drops during parabolic flights, sounding rocket missions, and using the electro-magnetic levitator multi-user facility on board the International Space Station. The comparison of both sets of experiments in 1 g and µg leads to an estimation of the influence of forced convection on dendrite growth kinetics and microstructure evolution.

Advanced ice protection systems test in the NASA Lewis icing research tunnel

NASA Technical Reports Server (NTRS)

Bond, Thomas H.; Shin, Jaiwon; Mesander, Geert A.

1991-01-01

Tests of eight different deicing systems based on variations of three different technologies were conducted in the NASA Lewis Research Center Icing Research Tunnel (IRT) in June and July 1990. The systems used pneumatic, eddy current repulsive, and electro-expulsive means to shed ice. The tests were conducted on a 1.83 m span, 0.53 m chord NACA 0012 airfoil operated at a 4 degree angle of attack. The models were tested at two temperatures: a glaze condition at minus 3.9 C and a rime condition at minus 17.2 C. The systems were tested through a range of icing spray times and cycling rates. Characterization of the deicers was accomplished by monitoring power consumption, ice shed particle size, and residual ice. High speed video motion analysis was performed to quantify ice particle size.

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

Rioux, Robert M.

In this work, we have primarily utilized isothermal titration calorimetry (ITC) and complimentary catalyst characterization techniques to study and assess the impact of solution conditions (i.e., solid-liquid) interface on the synthesis of heterogeneous and electro-catalysts. Isothermal titration calorimetry is well-known technique from biochemistry/physics, but has been applied to a far lesser extent to characterize buried solid-liquid interfaces in materials science. We demonstrate the utility and unique information provided by ITC for two distinct catalytic systems. We explored the thermodynamics associated catalyst synthesis for two systems: (i) ion-exchange or strong electrostatic adsorption for Pt and Pd salts on silica and aluminamore » materials (ii) adsorption to provide covalent attachment of metal and metal-oxo clusters to Dion-Jacobsen perovskite materials.« less

Simultaneous Extraction Optimization and Analysis of Flavonoids from the Flowers of Tabernaemontana heyneana by High Performance Liquid Chromatography Coupled to Diode Array Detector and Electron Spray Ionization/Mass Spectrometry

PubMed Central

Sathishkumar, Thiyagarajan; Baskar, Ramakrishnan; Aravind, Mohan; Tilak, Suryanarayanan; Deepthi, Sri; Bharathikumar, Vellalore Maruthachalam

2013-01-01

Flavonoids are exploited as antioxidants, antimicrobial, antithrombogenic, antiviral, and antihypercholesterolemic agents. Normally, conventional extraction techniques like soxhlet or shake flask methods provide low yield of flavonoids with structural loss, and thereby, these techniques may be considered as inefficient. In this regard, an attempt was made to optimize the flavonoid extraction using orthogonal design of experiment and subsequent structural elucidation by high-performance liquid chromatography-diode array detector-electron spray ionization/mass spectrometry (HPLC-DAD-ESI/MS) techniques. The shake flask method of flavonoid extraction was observed to provide a yield of 1.2 ± 0.13 (mg/g tissue). With the two different solvents, namely, ethanol and ethyl acetate, tried for the extraction optimization of flavonoid, ethanol (80.1 mg/g tissue) has been proved better than ethyl acetate (20.5 mg/g tissue). The optimal conditions of the extraction of flavonoid were found to be 85°C, 3 hours with a material ratio of 1 : 20, 75% ethanol, and 1 cycle of extraction. About seven different phenolics like robinin, quercetin, rutin, sinapoyl-hexoside, dicaffeic acid, and two unknown compounds were identified for the first time in the flowers of T. heyneana. The study has also concluded that L16 orthogonal design of experiment is an effective method for the extraction of flavonoid than the shake flask method. PMID:25969771

Electro-optical hybrid slip ring

NASA Astrophysics Data System (ADS)

Hong, En

2005-11-01

The slip ring is a rotary electrical interface, collector, swivel or rotary joint. It is a physical system that can perform continuous data transfer and data exchange between a stationary and a rotating structure. A slip ring is generally used to transfer data or power from an unrestrained, continuously rotating electro-mechanical system in real-time, thereby simplifying operations and eliminating damage-prone wires dangling from moving joints. Slip rings are widely used for testing, evaluating, developing and improving various technical equipment and facilities with rotating parts. They are widely used in industry, especially in manufacturing industries employing turbo machinery, as in aviation, shipbuilding, aerospace, defense, and in precise facilities having rotating parts such as medical Computerized Tomography (CT) and MRI scanners and so forth. Therefore, any improvement in slip ring technology can impact large markets. Research and development in this field will have broad prospects long into the future. The goal in developing the current slip ring technology is to improve and increase the reliability, stability, anti-interference, and high data fidelity between rotating and stationary structures. Up to now, there have been numerous approaches used for signal and data transfer utilizing a slip ring such as metal contacts, wires, radio transmission, and even liquid media. However, all suffer from drawbacks such as data transfer speed limitations, reliability, stability, electro-magnetic interference and durability. The purpose of the current research is to break through these basic limitations using an optical solution, thereby improving performance in current slip ring applications. This dissertation introduces a novel Electro-Optical Hybrid Slip Ring technology, which makes "through the air" digital-optical communication between stationary and rotating systems a reality with high data transfer speed, better reliability and low interference susceptibility. A laboratory scale non-contact Electro-Optical Hybrid Slip Ring system was successfully constructed, and its performance was determined. Experimental results affirmed the advantages of this new technology over current slip ring design.

Selenization of CIS and CIGS layers deposited by chemical spray pyrolysis

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

Babu, B. J.; Egaas, B.; Velumani, S.

Cu(In1-xGax)Se2 (CIGS) thin films with x=0 (CIS) and x=0.3 (CIGS) were prepared on Mo-coated glass substrate by using chemical spray pyrolysis at a substrate temperature of 350 degrees C, followed by selenization treatment at 550 degrees C in selenium environment under N2 gas flow. X-ray diffraction patterns of as-deposited CIGS layers on Mo showed polycrystalline chalcopyrite phase with an intense (112) plane. Splitting of (204)/(220) and (116)/(312) planes for the film with x=0.3 reveals deviation of tetragonal nature. Field emission scanning electron microscopy cross-sectional images of selenized films showed clear re-crystallization of grains. During the selenization process of the CIGSmore » absorber, a thin interface layer of MoSe2 is formed. Line mapping of Mo/CIGS layer showed more gallium segregation at the interface of back contact resulting in band gap grading. Chemical composition and mapping of the as-deposited and selenized samples were determined by energy dispersive analysis of X-rays. This work leads to fabrication of low cost and large scale Mo/CIGS/CdS/ZnO/ZnO:Al device structure.« less

Oxidation behavior of thermal barrier coating systems with Al interlayer under isothermal loading

NASA Astrophysics Data System (ADS)

Ali, I.; Sokołowski, P.; Grund, T.; Pawłowski, L.; Lampke, T.

2018-06-01

In the present study, the phenomena related to the Thermally Grown Oxides (TGO) in atmospheric plasma sprayed Thermal Barrier Coatings (TBCs) are discussed. CoNiCrAlY bond coatings were sprayed on Inconel 600 substrates. Subsequently, thin Al layers were deposited by DC-Magnetron sputtering. Finally, yttria-stabilized zirconia (YSZ) top coatings were deposited to form a three-layered TBC system. The thus produced aluminum interlayer containing thermal barrier coatings (Al-TBC) were subjected to isothermal exposure with different holding times at 1150 °C and compared with reference TBCs of the same kind, but without Al interlayers (R-TBC). The oxide film formation in the interface between bond coating (BC) and top coating (TC) was investigated by scanning electron microscope (SEM) after 100 and 300 h of high temperature isothermal exposure. The growth of this oxide film as a function of the isothermal exposure time was studied. As a result, the designed Al-TBC system exhibited better oxidation resistance in the BC/TC interface than the two-layered R-TBC system. This was lead back to the Al enrichment, which slows down the formation rate of transition metal oxides during thermal loading.

Aircraft Propeller Hub Repair

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

Muth, Thomas R.; Peter, William H.

The team performed a literature review, conducted residual stress measurements, performed failure analysis, and demonstrated a solid state additive manufacturing repair technique on samples removed from a scrapped propeller hub. The team evaluated multiple options for hub repair that included existing metal buildup technologies that the Federal Aviation Administration (FAA) has already embraced, such as cold spray, high velocity oxy-fuel deposition (HVOF), and plasma spray. In addition the team helped Piedmont Propulsion Systems, LLC (PPS) evaluate three potential solutions that could be deployed at different stages in the life cycle of aluminum alloy hubs, in addition to the conventional spraymore » coating method for repair. For new hubs, a machining practice to prevent fretting with the steel drive shaft was recommended. For hubs that were refurbished with some material remaining above the minimal material condition (MMC), a silver interface applied by an electromagnetic pulse additive manufacturing method was recommended. For hubs that were at or below the MMC, a solid state additive manufacturing technique using ultrasonic welding (UW) of thin layers of 7075 aluminum to the hub interface was recommended. A cladding demonstration using the UW technique achieved mechanical bonding of the layers showing promise as a viable repair method.« less

A framework to monitor activities of satellite data processing in real-time

NASA Astrophysics Data System (ADS)

Nguyen, M. D.; Kryukov, A. P.

2018-01-01

Space Monitoring Data Center (SMDC) of SINP MSU is one of the several centers in the world that collects data on the radiational conditions in near-Earth orbit from various Russian (Lomonosov, Electro-L1, Electro-L2, Meteor-M1, Meteor-M2, etc.) and foreign (GOES 13, GOES 15, ACE, SDO, etc.) satellites. The primary purposes of SMDC are: aggregating heterogeneous data from different sources; providing a unified interface for data retrieval, visualization, analysis, as well as development and testing new space weather models; and controlling the correctness and completeness of data. Space weather models rely on data provided by SMDC to produce forecasts. Therefore, monitoring the whole data processing cycle is crucial for further success in the modeling of physical processes in near-Earth orbit based on the collected data. To solve the problem described above, we have developed a framework called Live Monitor at SMDC. Live Monitor allows watching all stages and program components involved in each data processing cycle. All activities of each stage are logged by Live Monitor and shown in real-time on a web interface. When an error occurs, a notification message will be sent to satellite operators via email and the Telegram messenger service so that they could take measures in time. The Live Monitor’s API can be used to create a customized monitoring service with minimum coding.

Containerless crystallization of silicon

NASA Astrophysics Data System (ADS)

Kuribayashi, K.; Aoyama, T.

2002-04-01

Crystallization from undercooled melt of silicon was carried out by means of electro-magnetic levitation method under controlled undercooling. The measured growth rate vs. undercooling was categorized into three regions, I, II and III, respectively, from the point of the interface morphology. Thin plate crystals whose interface consisted of both faceted (1 1 1) plane and wavy edge plane like saw-tooth were observed in the region I where the undercooling is less than 100 K. The growth rate of the wavy edge plane was well described by the dendrite growth model. The morphology of growing crystals was abruptly changed to faceted dendrite in the region II, though there was no abrupt change in the growth rate. Seeding at temperatures in the region I changes the drop to a mono-crystalline sphere, if the growth rate along the normal direction of the thin plate crystal is controlled by step-wise growth on the faceted plane. Actually, the sample of 5 mm in diameter seeded at undercooling of 26 K was a quasi-single crystal with large grain, except for a small area where twinning and cracking are observed. The result suggests that the single crystal could be grown, if a smaller sample, 1 or 2 mm in diameter, that is difficult to be levitated by electro-magnetic force were processed with other methods such as free fall in a drop tube.

Microencapsulation by spray-drying of anthocyanin pigments from Corozo ( Bactris guineensis) fruit.

PubMed

Osorio, Coralia; Acevedo, Baudilio; Hillebrand, Silke; Carriazo, José; Winterhalter, Peter; Morales, Alicia Lucía

2010-06-09

The anthocyanins of Bactris guineensis fruit were isolated with the aid of high-speed countercurrent chromatography (HSCCC) and preparative HPLC, and their chemical structures were elucidated by using spectroscopic methods. Among the identified pigments, cyanidin-3-rutinoside and cyanidin-3-glucoside were characterized as major constituents (87.9%). Peonidin-3-rutinoside, peonidin-3-glucoside, cyanidin-3-(6-O-malonyl)glucoside, and cyanidin-3-sambubioside were present in minor amounts. Four anthocyanin ethanolic extracts (AEEs) were obtained by osmotic dehydration and Soxhlet extraction and physicochemically characterized. The composition of anthocyanins was monitored by HPLC-PDA. The extracts with the highest anthocyanin content were subjected to the spray-drying process with maltodextrin. The so-obtained spray-dried powders were analyzed by scanning electron microscopy (SEM) and found to consist of spherical particles <50 microm in size. The anthocyanin composition was similar to that of the fruit. The microencapsulated powders were analyzed by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC), revealing that they are quite stable until 100 degrees C. Storage stability tests of microcapsules showed that the release of anthocyanin pigments follows pseudo-first-order kinetics and that the process rate is increased by temperature and humidity. The most suitable conditions for storage were below 37 degrees C and <76% relative humidity, respectively.

In vitro and in vivo mechanical evaluations of plasma-sprayed hydroxyapatite coatings on titanium implants: the effect of coating characteristics.

PubMed

Yang, C Y; Lin, R M; Wang, B C; Lee, T M; Chang, E; Hang, Y S; Chen, P Q

1997-12-05

This study was undertaken to evaluate the effect of coating characteristics on the mechanical strengths of the plasma-sprayed HA-coated Ti-6Al-4V implant system both in vitro and in vivo. Two types of HA coatings (HACs) with quite different microstructures, concentrations of impurity-phases, and indices-of-crystallinity were used. In vitro testings were done by measuring the bonding-strength at the Ti-6Al-4V-HAC interface, with HACs that had and had not been immersed in a pH-buffered, serum-added simulated body fluid (SBF). The shear-strength at the HAC-bone interface was investigated in a canine transcortical femoral model after 12 and 24 weeks of implantation. The results showed a bonding degradation of approximately 32% or higher of the original strength after 4 weeks of immersion in SBF, and this predominantly depended on the constructed microstructure of the HACs. After the push-out measurements, it was demonstrated that the HACs with higher bonding-strength in vitro would correspondingly result in significantly higher shear-strength at each implant period in vivo. Nevertheless, there were no substantial histological variations between the two types of HACs evaluated. The most important point elucidated in this study was that, among coating characteristics, the microstructure was the key factor in influencing the mechanical stability of the HACs both in vitro and in vivo. As a consequence, a denser HAC was needed to ensure mechanical stability at both interfaces.

Microencapsulation of nanoemulsions: novel Trojan particles for bioactive lipid molecule delivery

PubMed Central

Li, Xiang; Anton, Nicolas; Ta, Thi Minh Chau; Zhao, Minjie; Messaddeq, Nadia; Vandamme, Thierry F

2011-01-01

Background Nanoemulsions consist of very stable nanodroplets of oil dispersed in an aqueous phase, typically below 300 nm in size. They can be used to obtain a very fine, homogeneous dispersion of lipophilic compounds in water, thus facilitating their handling and use in nanomedicine. However, the drawback is that they are suspended in an aqueous media. This study proposes a novel technique for drying lipid nanoemulsion suspensions to create so-called Trojan particles, ie, polymer microparticles (around 2 μm) which very homogeneously “entrap” the nano-oil droplets (around 150 nm) in their core. Methods Microencapsulation of the nanoemulsions was performed using a spray-drying process and resulted in a dried powder of microparticles. By using a low-energy nanoemulsification method and relatively gentle spray-drying, the process was well suited to sensitive molecules. The model lipophilic molecule tested was vitamin E acetate, encapsulated at around 20% in dried powder. Results We showed that the presence of nanoemulsions in solution before spray-drying had a significant impact on microparticle size, distribution, and morphology. However, the process itself did not destroy the oil nanodroplets, which could easily be redispersed when the powder was put back in contact with water. High-performance liquid chromatography follow-up of the integrity of the vitamin E acetate showed that the molecules were intact throughout the process, as well as when conserved in their dried form. Conclusion This study proposes a novel technique using a spray-drying process to microencapsulate nanoemulsions. The multiscale object formed, so-called Trojan microparticles, were shown to successfully encapsulate, protect, and release the lipid nanodroplets. PMID:21760727

Microencapsulation of nanoemulsions: novel Trojan particles for bioactive lipid molecule delivery.

PubMed

Li, Xiang; Anton, Nicolas; Ta, Thi Minh Chau; Zhao, Minjie; Messaddeq, Nadia; Vandamme, Thierry F

2011-01-01

Nanoemulsions consist of very stable nanodroplets of oil dispersed in an aqueous phase, typically below 300 nm in size. They can be used to obtain a very fine, homogeneous dispersion of lipophilic compounds in water, thus facilitating their handling and use in nanomedicine. However, the drawback is that they are suspended in an aqueous media. This study proposes a novel technique for drying lipid nanoemulsion suspensions to create so-called Trojan particles, ie, polymer microparticles (around 2 μm) which very homogeneously "entrap" the nano-oil droplets (around 150 nm) in their core. Microencapsulation of the nanoemulsions was performed using a spray-drying process and resulted in a dried powder of microparticles. By using a low-energy nanoemulsification method and relatively gentle spray-drying, the process was well suited to sensitive molecules. The model lipophilic molecule tested was vitamin E acetate, encapsulated at around 20% in dried powder. We showed that the presence of nanoemulsions in solution before spray-drying had a significant impact on microparticle size, distribution, and morphology. However, the process itself did not destroy the oil nanodroplets, which could easily be redispersed when the powder was put back in contact with water. High-performance liquid chromatography follow-up of the integrity of the vitamin E acetate showed that the molecules were intact throughout the process, as well as when conserved in their dried form. This study proposes a novel technique using a spray-drying process to microencapsulate nanoemulsions. The multiscale object formed, so-called Trojan microparticles, were shown to successfully encapsulate, protect, and release the lipid nanodroplets.

Robust composite-shell microcapsules via pickering emulsification.

PubMed

Patchan, Marcia W; Fuller, Benedict W; Baird, Lance M; Gong, Paul K; Walter, Erich C; Vidmar, Brendan J; Kyei, Ike; Xia, Zhiyong; Benkoski, Jason J

2015-04-08

Microencapsulation technology has been increasingly applied toward the development of self-healing paints. Added to paint as a dry powder prior to spraying, the microcapsules store a liquid that can repair the protective barrier layer if released into a scratch. However, self-healing will not occur unless the microcapsules can withstand spray-painting, aggressive solvents in the paint, and long-term exposure to the elements. We have therefore developed a one-pot synthesis for the production of Pickering microcapsules with outstanding strength, solvent resistance, and barrier properties. Octadecyltrimethoxysilane-filled (OTS) microcapsules form via standard interfacial polycondensation, except that silica nanopowder (10-20 nm diameter) replaces the conventional surfactant or hydrocolloid emulsifier. Isophorone diisocyanate (IPDI) in the OTS core reacts with diethylenetriamine, polyethylenimine, and water to form a hard polymer shell along the interface. Compared to pure polyurea, the silica-polyurea composite improves the shelf life of the OTS by 10 times. The addition of SiO2 prevents leaching of OTS into xylenes and hexanes for up to 80 days, and the resulting microcapsules survive nebulization through a spray gun at 620 kPa in a 500 cSt fluid.

Microstructural Analysis and Transport Properties of Thermally Sprayed Multiple-Layer Ceramic Coatings

NASA Astrophysics Data System (ADS)

Wang, Hsin; Muralidharan, Govindarajan; Leonard, Donovan N.; Haynes, J. Allen; Porter, Wallace D.; England, Roger D.; Hays, Michael; Dwivedi, Gopal; Sampath, Sanjay

2018-02-01

Multilayer, graded ceramic/metal coatings were prepared by an air plasma spray method on Ti-6Al-4V, 4140 steel and graphite substrates. The coatings were designed to provide thermal barriers for diesel engine pistons to operate at higher temperatures with improved thermal efficiency and cleaner emissions. A systematic, progressive variation in the mixture of yttria-stabilized zirconia and bondcoat alloys (NiCoCrAlYHfSi) was designed to provide better thermal expansion match with the substrate and to improve thermal shock resistance and cycle life. Heat transfer through the layers was evaluated by a flash diffusivity technique based on a model of one-dimensional heat flow. The aging effect of the as-sprayed coatings was captured during diffusivity measurements, which included one heating and cooling cycle. The hysteresis of thermal diffusivity due to aging was not observed after 100-h annealing at 800 °C. The measurements of coatings on substrate and freestanding coatings allowed the influence of interface resistance to be evaluated. The microstructure of the multilayer coating was examined using scanning electron microscope and electron probe microanalysis.

Measurements of the Diameter and Velocity Distributions of Atomized Tablet-Coating Solutions for Pharmaceutical Applications

NASA Astrophysics Data System (ADS)

Osterday, Kathryn; Aliseda, Alberto; Lasheras, Juan

2009-11-01

The atomization of colloidal suspensions is of particular interest to the manufacturing of tablets and pills used as drug delivery systems by the pharmaceutical industry. At various stages in the manufacturing process, the tablets are coated with a spray of droplets produced by co-axial atomizers. The mechanisms of droplet size and spray formation in these types of atomizers are dominated by Kelvin-Helmholtz and Raleigh-Taylor instabilities for both low[1] and high[2] Ohnesorge numbers. We present detailed phase Doppler measurements of the Sauter Mean Diameter of the droplets produced by co-axial spray atomizers using water-based colloidal suspensions with solid concentrations ranging from fifteen to twenty percent and acetone-based colloidal suspensions with solid concentrations ranging from five to ten percent. Our results compare favorably with predictions by Aliseda's model. This suggests that the final size distribution is mainly determined by the instabilities caused by the sudden acceleration of the liquid interface. [1]Varga, C. M., et al. (2003) J. Fluid Mech. 497:405-434 [2]Aliseda, A. et al. (2008). J. Int. J. Multiphase Flow, 34(2), 161-175.

Corrosion Control at Graphite/Epoxy-Aluminum and Titanium Interfaces

DTIC Science & Technology

1974-07-01

Exfoliation Salt Spray Showing Corrosion on Back Side of Bond Interface (2x) 18 19 20 23 24 27 31 31 32 32 33 33 34 35 ; vll...25 29 Vlll ’-■"■’"-’—’—’"■ •■■’■■: UtaMMUitaittikHMalMiiakii T= zsm ~ ■ - ■- • ’■ ■ -■■■ ■: ---"• SUMMARY Graphlte/epoxy...joint specimen. Cure M 35 psl and 3a0*F for GO minutes. Apply 0,2-0.4 ml ol BH127 adhesive primer to the bond intiiface areas. Bond 4 mil 1100

A study of electro-osmosis as applied to drilling engineering

NASA Astrophysics Data System (ADS)

Hariharan, Peringandoor Raman

In the present research project. the application of the process of electro-osmosis has been extended to a variety of rocks during the drilling operation. Electro-osmosis has been utilized extensively to examine its influence in reducing (i) bit balling, (ii) coefficient of friction between rock and metal and (iii) bit/tool wear. An attempt has been made to extend the envelope of confidence in which electro-osmosis was found to be operating satisfactorily. For all the above cases the current requirements during electro-osmosis were identified and were recorded. A novel test method providing repeatable results has been developed to study the problem of bit balling in the laboratory through the design of a special metallic bob simulating the drill bit. A numerical parameter described as the Degree-of-Balling (DOB) defined by the amount of cuttings stuck per unit volume of rock cut for the same duration of time is being proposed as a means to quantitatively describe the balling process in the laboratory. Five different types of shales (Pierre I & II, Catoosa, Mancos and Wellington) were compared and evaluated for balling characteristics and to determine the best conditions for reducing bit balling with electro-osmosis in a variety of drilling fluids including fresh water, polymer solutions and field type drilling fluids. Through the design, fabrication and performing of experiments conducted with a model Bottom Hole Assembly (BHA). the feasibility of maintaining the drill bit separately at a negative potential and causing the current to flow through the rock back into the string through a near bit stabilizer has been demonstrated. Experiments conducted with this self contained arrangement for the application of electro-osmosis have demonstrated a substantial decrease in balling and increase in the rate of penetration (ROP) while drilling with both a roller cone and PDC microbit (1-1/4" dia.) in Pierre I and Wellington shales. It is believed that the results obtained from the model BHA will aid in scaling up to a full-scale prototype BHA for possible application in the field. Experiments conducted with electro-osmosis in a simulated drill string under loaded conditions have clearly demonstrated that the coefficient of friction (mu) can be reduced at the interface of a rotating cylinder (simulating the drill-pipe) and a rock (usually a type of shale), through electro-osmosis. Studies examined the influence of many variables such as drilling fluid, rock type, and current on mu. The need for the correct estimation of mu is for reliable correlation between values obtained in the laboratory with those observed in the field. The knowledge of the coefficient of friction (mu) is an important requirement for drill string design and well trajectory planning. The use of electro-osmosis in reducing bit/tool wear through experiments in various rocks utilizing a specially designed steel bob simulating the drill bit has clearly indicated a decreased average tool wear, varying from 35% in Pierre I shale up to 57% in sandstone when used with the tool maintained at a cathodic DC potential. (Abstract shortened by UMI.)

Development of an automated high-temperature valveless injection system for online gas chromatography

NASA Astrophysics Data System (ADS)

Kreisberg, N. M.; Worton, D. R.; Zhao, Y.; Isaacman, G.; Goldstein, A. H.; Hering, S. V.

2014-12-01

A reliable method of sample introduction is presented for online gas chromatography with a special application to in situ field portable atmospheric sampling instruments. A traditional multi-port valve is replaced with a valveless sample introduction interface that offers the advantage of long-term reliability and stable sample transfer efficiency. An engineering design model is presented and tested that allows customizing this pressure-switching-based device for other applications. Flow model accuracy is within measurement accuracy (1%) when parameters are tuned for an ambient-pressure detector and 15% accurate when applied to a vacuum-based detector. Laboratory comparisons made between the two methods of sample introduction using a thermal desorption aerosol gas chromatograph (TAG) show that the new interface has approximately 3 times greater reproducibility maintained over the equivalent of a week of continuous sampling. Field performance results for two versions of the valveless interface used in the in situ instrument demonstrate typically less than 2% week-1 response trending and a zero failure rate during field deployments ranging up to 4 weeks of continuous sampling. Extension of the valveless interface to dual collection cells is presented with less than 3% cell-to-cell carryover.

Development of an automated high-temperature valveless injection system for online gas chromatography

DOE PAGES

Kreisberg, N. M.; Worton, D. R.; Zhao, Y.; ...

2014-12-12

A reliable method of sample introduction is presented for online gas chromatography with a special application to in situ field portable atmospheric sampling instruments. A traditional multi-port valve is replaced with a valveless sample introduction interface that offers the advantage of long-term reliability and stable sample transfer efficiency. An engineering design model is presented and tested that allows customizing this pressure-switching-based device for other applications. Flow model accuracy is within measurement accuracy (1%) when parameters are tuned for an ambient-pressure detector and 15% accurate when applied to a vacuum-based detector. Laboratory comparisons made between the two methods of sample introductionmore » using a thermal desorption aerosol gas chromatograph (TAG) show that the new interface has approximately 3 times greater reproducibility maintained over the equivalent of a week of continuous sampling. Field performance results for two versions of the valveless interface used in the in situ instrument demonstrate typically less than 2% week -1 response trending and a zero failure rate during field deployments ranging up to 4 weeks of continuous sampling. Extension of the valveless interface to dual collection cells is presented with less than 3% cell-to-cell carryover.« less

Failure modes of vacuum plasma spray tungsten coating created on carbon fibre composites under thermal loads

NASA Astrophysics Data System (ADS)

Hirai, T.; Bekris, N.; Coad, J. P.; Grisolia, C.; Linke, J.; Maier, H.; Matthews, G. F.; Philipps, V.; Wessel, E.

2009-07-01

Vacuum plasma spray tungsten (VPS-W) coating created on a carbon fibre reinforced composite (CFC) was tested under two thermal load schemes in the electron beam facility to examine the operation limits and failure modes. In cyclic ELM-like short transient thermal loads, the VPS-W coating was destroyed sub-layer by sub-layer at 0.33 GW/m 2 for 1 ms pulse duration. At longer single pulses, simulating steady-state thermal loads, the coating was destroyed at surface temperatures above 2700 °C by melting of the rhenium containing multilayer at the interface between VPS-W and CFC. The operation limits and failure modes of the VPS-W coating in the thermal load schemes are discussed in detail.

Microfabricated polymer injector for direct mass spectrometry coupling.

PubMed

Gobry, Véronique; van Oostrum, Jan; Martinelli, Marco; Rohner, Tatiana C; Reymond, Frédéric; Rossier, Joël S; Girault, Hubert H

2002-04-01

This paper demonstrates the coupling of a plasma etched polymer microfluidic system with an electrospray mass spectrometer by generation of a nanospray. Taking advantage of the microtechnology processes and polymer properties, high volume production with good reproducibility of hydrophobic interfaces could be obtained. The nanospray was directly produced from the outlet of the plastic microfabricated chip positioned in front of the capillary entrance of the mass spectrometer. No chemical background due to the polymer has been observed under standard nanospray conditions. The performances of the spray as well as its efficiency have been demonstrated by flow measurements, stability establishment and tandem mass spectrometry experiment on angiotensin II. The spray was actuated without additional flow in methanol: water:acetic acid (50:49:1%) solution. A 40 fmol/microL detection limit could be reached.

Numerical modeling of spray combustion with an advanced VOF method

NASA Technical Reports Server (NTRS)

Chen, Yen-Sen; Shang, Huan-Min; Shih, Ming-Hsin; Liaw, Paul

1995-01-01

This paper summarizes the technical development and validation of a multiphase computational fluid dynamics (CFD) numerical method using the volume-of-fluid (VOF) model and a Lagrangian tracking model which can be employed to analyze general multiphase flow problems with free surface mechanism. The gas-liquid interface mass, momentum and energy conservation relationships are modeled by continuum surface mechanisms. A new solution method is developed such that the present VOF model can be applied for all-speed flow regimes. The objectives of the present study are to develop and verify the fractional volume-of-fluid cell partitioning approach into a predictor-corrector algorithm and to demonstrate the effectiveness of the present approach by simulating benchmark problems including laminar impinging jets, shear coaxial jet atomization and shear coaxial spray combustion flows.

Structural and magnetic depth profiles of magneto-ionic heterostructures beyond the interface limit

DOE PAGES

Gilbert, Dustin A.; Grutter, Alexander J.; Arenholz, Elke; ...

2016-07-22

Electric field control of magnetism provides a promising route towards ultralow power information storage and sensor technologies. The effects of magneto-ionic motion have been prominently featured in the modification of interface characteristics. Here, we demonstrate magnetoelectric coupling moderated by voltage-driven oxygen migration beyond the interface in relatively thick AlO x/GdO x/Co(15 nm) films. Oxygen migration and Co magnetization are quantitatively mapped with polarized neutron reflectometry under electro-thermal conditioning. The depth-resolved profiles uniquely identify interfacial and bulk behaviours and a semi-reversible control of the magnetization. Magnetometry measurements suggest changes in the microstructure which disrupt long-range ferromagnetic ordering, resulting in an additionalmore » magnetically soft phase. X-ray spectroscopy confirms changes in the Co oxidation state, but not in the Gd, suggesting that the GdO x transmits oxygen but does not source or sink it. These results together provide crucial insight into controlling magnetism via magneto-ionic motion, both at interfaces and throughout the bulk of the films.« less

In Situ Mass Spectrometric Monitoring of the Dynamic Electrochemical Process at the Electrode–Electrolyte Interface: a SIMS Approach

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

Wang, Zhaoying; Zhang, Yanyan; Liu, Bingwen

The in situ molecular characterization of reaction intermediates and products at electrode-electrolyte interfaces is central to mechanistic studies of complex electrochemical processes, yet a great challenge. The coupling of electrochemistry (EC) and mass spectrometry (MS) has seen rapid development and found broad applicability in tackling challenges in analytical and bioanalytical chemistry. However, few truly in situ and real-time EC-MS studies have been reported at electrode-electrolyte interfaces. An innovative EC-MS coupling method named in situ liquid secondary ion mass spectrometry (SIMS) was recently developed by combining SIMS with a vacuum compatible microfluidic electrochemical device. Using this novel capability we report themore » first in situ elucidation of the electro-oxidation mechanism of a biologically significant organic compound, ascorbic acid (AA), at the electrode-electrolyte interface. The short-lived radical intermediate was successfully captured, which had not been detected directly before. Moreover, we demonstrated the power of this new technique in real-time monitoring of the formation and dynamic evolution of electrical double layers at the electrode-electrolyte interface. This work suggests further promising applications of in situ liquid SIMS in studying more complex chemical and biological events at the electrode-electrolyte interface.« less

Selectivity and Longevity of Peripheral-Nerve and Machine Interfaces: A Review

PubMed Central

Ghafoor, Usman; Kim, Sohee; Hong, Keum-Shik

2017-01-01

For those individuals with upper-extremity amputation, a daily normal living activity is no longer possible or it requires additional effort and time. With the aim of restoring their sensory and motor functions, theoretical and technological investigations have been carried out in the field of neuroprosthetic systems. For transmission of sensory feedback, several interfacing modalities including indirect (non-invasive), direct-to-peripheral-nerve (invasive), and cortical stimulation have been applied. Peripheral nerve interfaces demonstrate an edge over the cortical interfaces due to the sensitivity in attaining cortical brain signals. The peripheral nerve interfaces are highly dependent on interface designs and are required to be biocompatible with the nerves to achieve prolonged stability and longevity. Another criterion is the selection of nerves that allows minimal invasiveness and damages as well as high selectivity for a large number of nerve fascicles. In this paper, we review the nerve-machine interface modalities noted above with more focus on peripheral nerve interfaces, which are responsible for provision of sensory feedback. The invasive interfaces for recording and stimulation of electro-neurographic signals include intra-fascicular, regenerative-type interfaces that provide multiple contact channels to a group of axons inside the nerve and the extra-neural-cuff-type interfaces that enable interaction with many axons around the periphery of the nerve. Section Current Prosthetic Technology summarizes the advancements made to date in the field of neuroprosthetics toward the achievement of a bidirectional nerve-machine interface with more focus on sensory feedback. In the Discussion section, the authors propose a hybrid interface technique for achieving better selectivity and long-term stability using the available nerve interfacing techniques. PMID:29163122

The use of inverse phase gas chromatography to measure the surface energy of crystalline, amorphous, and recently milled lactose.

PubMed

Newell, H E; Buckton, G; Butler, D A; Thielmann, F; Williams, D R

2001-05-01

To assess differences in surface energy due to processing induced disorder and to understand whether the disorder dominated the surfaces of particles. Inverse gas chromatography was used to compare the surface energies of crystalline, amorphous, and ball milled lactose. The milling process made ca 1% of the lactose amorphous, however the dispersive contribution to surface energy was 31.2, 37.1, and 41.6 mJ m(-2) for crystalline, spray dried and milled lactose, respectively. A physical mixture of crystalline (99%) and amorphous (1%) material had a dispersive surface energy of 31.5 mJ m(-2). Milling had made the surface energy similar to that of the amorphous material in a manner that was very different to a physical mixture of the same amorphous content. The milled material will have similar interfacial interactions to the 100% amorphous material.

Quantitative determination of the hydrolysis products of nitrogen mustards in human urine by liquid chromatography-electrospray ionization tandem mass spectrometry.

PubMed

Lemire, Sharon W; Ashley, David L; Calafat, Antonia M

2003-01-01

Nitrogen mustards are a public health concern because of their extreme vesicant properties and the possible exposure of workers during the destruction of chemical stockpiles. A sensitive, rapid, accurate, and precise analysis for the quantitation of ultratrace levels of N-ethyldiethanolamine (EDEA) and N-methyldiethanolamine (MDEA) in human urine as a means of assessing recent exposure to the nitrogen mustards bis(2-chloroethyl)ethylamine and bis(2-chloroethyl)methylamine, respectively, was developed. The method was based on solid-phase extraction, followed by analysis of the urine extract using isotope-dilution high-performance liquid chromatography-mass spectrometry with TurbolonSpray ionization and multiple-reaction monitoring. The method limits of detection were 0.41 ng/mL for EDEA and 0.96 ng/mL for MDEA in 1 mL of urine with coefficients of variation < 10% for both compounds.

Synthesis, Characterization and Decomposition Studies of Tris(N,N-dibenzyldithiocarbamato) Indium(III): Chemical Spray Deposition of Polycrystalline CuInS2 on Copper Films

NASA Technical Reports Server (NTRS)

Hehemann, David G.; Lau, J. Eva; Harris, Jerry D.; Hoops, Michael D.; Duffy, Norman V.; Fanwick, Philip E.; Khan, Osman; Jin, Michael H.-C.; Hepp, Aloysius F.

2005-01-01

Tris(bis(phenylmethyl)carbamodithioato-S,S ), commonly referred to as tris(N,Ndibenzyldithiocarbamato) indium(III), In(S2CNBz2)3, was synthesized and characterized by single crystal X-ray crystallography. The compound crystallizes in the triclinic space group P1 bar with two molecules per unit cell. The material was further characterized using a novel analytical system employing the combined powers of thermogravimetric analysis, gas chromatography/mass spectrometry and Fourier-Transform infrared spectroscopy to investigate its potential use as a precursor for the chemical vapor deposition (CVD) of thin film materials for photovoltaic applications. Upon heating, the material thermally decomposes to release CS2 and benzyl moieties in to the gas phase, resulting in bulk In2S3. Preliminary spray CVD experiments indicate that In(S2CNBz2)3 decomposed on a Cu substrate reacts to produce stoichiometric CuInS2 films.

[Mechanism and performance of styrene oxidation by O3/H2O2].

PubMed

He, Jue-Cong; Huang, Qian-Ru; Ye, Qi-Hong; Luo, Yu-Wei; Zhang, Zai-Li; Fan, Qing-Juan; Wei, Zai-Shan

2013-10-01

It can produce a large number of free radicals in O3/H2O2, system, ozone and free radical coupling oxidation can improve the styrene removal efficiency. Styrene oxidation by O3/H2O2 was investigated. Ozone dosage, residence time, H2o2 volume fraction, spray density and molar ratio of O3/C8H8 on styrene removal were evaluated. The experimental results showed that styrene removal efficiency achieved 85.7%. The optimal residence time, H2O2, volume fraction, spray density and O3/C8H8 molar ratio were 20. 6 s, 10% , 1.72 m3.(m2.h)-1 and 0.46, respectively. The gas-phase degradation intermediate products were benzaldehyde(C6H5CHO) and benzoic acid (C6H5 COOH) , which were identified by means of gas chromatography-mass spectrometry(GC-MS). The degradation mechanism of styrene is presented.

Development of a Portable Sensitive Equipment Decontamination System. Volume 2: Activated Carbon Fiber Wipe

DTIC Science & Technology

2010-05-01

absorption. Thermogravimetric Analysis (TGA) was employed to measure absorption of HD and GD into the nylon fabric. TGA is an analytical tool useful in...Chromatography Analysis 26 4.4.5.1 Mass Removed by Wiper at Room Temperature 26 4.4.6 Chemical Agent Mass Removed by Wiper at Elevated and Reduced...Temperature Tests 71 5.9 Vapor Analysis of Spent Wipe 78 5.10 Wiping Efficacy and Complex Geometries 82 5.11 Spray and Wipe Tests 84 5.12 Effect of

Separation and characterisation of five polar herbicides using countercurrent chromatography with detection by negative ion electrospray ionisation mass spectrometry.

PubMed

Kidwell, H; Jones, J J; Games, D E

2001-01-01

Five polar herbicides were separated and characterised using high-speed analytical countercurrent chromatography (HSACCC) in conjunction with online electrospray mass spectrometry (ESI-MS). The countercurrent chromatography used a standard isocratic biphasic solvent system of hexane/ethyl acetate/methanol/water in reverse phase to effect the separation of these five environmentally important compounds. The chromatograph was coupled to a triple quadrupole mass spectrometer via a standard electrospray liquid chromatography interface that was able to give mass spectra in negative ion mode of each compound. Limits of detection are reported for this series of compounds along with representative negative ion ESI-MS data and calibrations for the separation. Copyright 2001 John Wiley & Sons, Ltd.

The Mesosphere and Thermosphere,

DTIC Science & Technology

1981-01-01

lar wind kinetic energy flux ( I erg cm s at 1 AU). The power inputlinto the magnetosphere with an effective radius of 10 R is of the order of 10 W...relative to the interfaces several h urs later thanPthe density. In addition, the higher power of v causes nv to be generally higher in fast streams than...this way c can be interpreted as "that portion of the solar wind electro- magnetic power flux which, at any one time, penetrates the magnetosphere

Airborne Electro-Mechanical Actuator Test Stand for Development of Prognostic Health Management Systems

DTIC Science & Technology

2010-10-01

based on a pre-defined UH-60 data format, then also computes the load and position profile information. File Profile Interface In order to test the...of the data set. Figure 13 shows a typical motion profile executed over a period of about twenty minutes. Figure 14 shows the desired ( computed ...flight. The stand is connected to the aircraft data bus and the motion profiles for the test actuators, as well as the load applied to them, are

Uncovering the Fundamental Nature of Tribological Interfaces: High Resolution Tribology and Spectroscopy of Ultrahard Nanostructured Diamond Films for MEMS and Beyond

DTIC Science & Technology

2007-12-31

Wisconsin-Madison) for 2? ol !> o "S \\ % M 31 Statement of Objectives The original objectives of the proposal were as follows: 1. Obtain high-quality...performed multiple PEEM experiments on wear tracks on carbon-based films and polysilicon micro-electro mechanical systems (MEMS) devices, a comprehensive... polysilicon MEMS device known as the "nanotractor", and studies of the structure and composition of UNCD, ta-C, and nanocrystalline diamond (NCD) films. They

Ultralow crosstalk nanosecond-scale nested 2 × 2 Mach-Zehnder silicon photonic switch.

PubMed

Dupuis, Nicolas; Rylyakov, Alexander V; Schow, Clint L; Kuchta, Daniel M; Baks, Christian W; Orcutt, Jason S; Gill, Douglas M; Green, William M J; Lee, Benjamin G

2016-07-01

We present the design and characterization of a novel electro-optic silicon photonic 2×2 nested Mach-Zehnder switch monolithically integrated with a CMOS driver and interface logic. The photonic device uses a variable optical attenuator in order to balance the power inside the Mach-Zehnder interferometer leading to ultralow crosstalk performance. We measured a crosstalk as low as -34.5  dB, while achieving ∼2  dB insertion loss and 4 ns transient response.

Spray Combustion Modeling with VOF and Finite-Rate Chemistry

NASA Technical Reports Server (NTRS)

Chen, Yen-Sen; Shang, Huan-Min; Liaw, Paul; Wang, Ten-See

1996-01-01

A spray atomization and combustion model is developed based on the volume-of-fluid (VOF) transport equation with finite-rate chemistry model. The gas-liquid interface mass, momentum and energy conservation laws are modeled by continuum surface force mechanisms. A new solution method is developed such that the present VOF model can be applied for all-speed range flows. The objectives of the present study are: (1) to develop and verify the fractional volume-of-fluid (VOF) cell partitioning approach into a predictor-corrector algorithm to deal with multiphase (gas-liquid) free surface flow problems; (2) to implement the developed unified algorithm in a general purpose computational fluid dynamics (CFD) code, Finite Difference Navier-Stokes (FDNS), with droplet dynamics and finite-rate chemistry models; and (3) to demonstrate the effectiveness of the present approach by simulating benchmark problems of jet breakup/spray atomization and combustion. Modeling multiphase fluid flows poses a significant challenge because a required boundary must be applied to a transient, irregular surface that is discontinuous, and the flow regimes considered can range from incompressible to highspeed compressible flows. The flow-process modeling is further complicated by surface tension, interfacial heat and mass transfer, spray formation and turbulence, and their interactions. The major contribution of the present method is to combine the novel feature of the Volume of Fluid (VOF) method and the Eulerian/Lagrangian method into a unified algorithm for efficient noniterative, time-accurate calculations of multiphase free surface flows valid at all speeds. The proposed method reformulated the VOF equation to strongly couple two distinct phases (liquid and gas), and tracks droplets on a Lagrangian frame when spray model is required, using a unified predictor-corrector technique to account for the non-linear linkages through the convective contributions of VOF. The discontinuities within the sharp interface will be modeled as a volume force to avoid stiffness. Formations of droplets, tracking of droplet dynamics and modeling of the droplet breakup/evaporation, are handled through the same unified predictor-corrector procedure. Thus the new algorithm is non-iterative and is flexible for general geometries with arbitrarily complex topology in free surfaces. The FDNS finite-difference Navier-Stokes code is employed as the baseline of the current development. Benchmark test cases of shear coaxial LOX/H2 liquid jet with atomization/combustion and impinging jet test cases are investigated in the present work. Preliminary data comparisons show good qualitative agreement between data and the present analysis. It is indicative from these results that the present method has great potential to become a general engineering design analysis and diagnostics tool for problems involving spray combustion.

Influence of spray drying and dispersing agent on surface and dissolution properties of griseofulvin micro and nanocrystals.

PubMed

Shah, Dhaval A; Patel, Manan; Murdande, Sharad B; Dave, Rutesh H

2016-11-01

The purpose for the current research is to compare and evaluate physiochemical properties of spray-dried (SD) microcrystals (MCs), nanocrystals (NCs), and nanocrystals with a dispersion agent (NCm) from a poorly soluble compound. The characterization was carried out by performing size and surface analysis, interfacial tension (at particle moisture interface), and in-vitro drug dissolution rate experiments. Nanosuspensions were prepared by media milling and were spray-dried. The SD powders that were obtained were characterized morphologically using scanning electron microscopy (SEM), polarized light microscopy (PLM), and Flowchem. Solid-state characterization was performed using X-ray powder diffraction (XRPD), Fourier transfer infrared spectroscopy (FT-IR), and differential scanning calorimetry (DSC) for the identification of the crystalline nature of all the SD powders. The powders were characterized for their redispersion tendency in the water and in pH 1.2. Significant differences in redispersion were noted for both the NCs in both dissolution media. The interfacial tension for particle moisture interface was determined by applying the BET (Braunauer-Emmett-Teller) equation to the vapor sorption data. No significant reduction in the interfacial tension was observed between MCs and NCs; however, a significant reduction in the interfacial tension was observed for NCm at both 25 °C and 35 °C temperatures. The difference in interfacial tension and redispersion behavior can be attributed to a difference in the wetting tendency for all the SD powders. The dissolution studies were carried out under sink and under non-sink conditions. The non-sink dissolution approach was found suitable for quantification of the dissolution rate enhancement, and also for providing the rank order to the SD formulations.

In vitro extracellular recording and stimulation performance of nanoporous gold-modified multi-electrode arrays.

PubMed

Kim, Yong Hee; Kim, Gook Hwa; Kim, Ah Young; Han, Young Hwan; Chung, Myung-Ae; Jung, Sang-Don

2015-12-01

Nanoporous gold (Au) structures can reduce the impedance and enhance the charge injection capability of multi-electrode arrays (MEAs) used for interfacing neuronal networks. Even though there are various nanoporous Au preparation techniques, fabrication of MEA based on low-cost electro-codeposition of Ag:Au has not been performed. In this work, we have modified a Au MEA via the electro-codeposition of Ag:Au alloy, followed by the chemical etching of Ag, and report on the in vitro extracellular recording and stimulation performance of the nanoporous Au-modified MEA. Ag:Au alloy was electro-codeposited on a bilayer lift-off resist sputter-deposition passivated Au MEA followed by chemical etching of Ag to form a porous Au structure. The porous Au structure was analyzed by scanning electron microscopy and tunneling electron microscopy and found to have an interconnected nanoporous Au structure. The impedance value of the nanoporous Au-modified MEA is 15.4 ± 0.55 kΩ at 1 kHz, accompanied by the base noise V rms of 2.4 ± 0.3 μV. The charge injection limit of the nanoporous Au-modified electrode estimated from voltage transient measurement is approximately 1 mC cm(-2), which is comparable to roughened platinum and carbon nanotube electrodes. The charge injection capability of the nanoporous Au-modified MEA was confirmed by observing stimulus-induced spikes at above 0.2 V. The nanoporous Au-modified MEA showed mechanical durability upon ultrasonic treatment for up to an hour. Electro-codeposition of Ag:Au alloy combined with chemical etching Ag is a low-cost process for fabricating nanoporous Au-modified MEA suitable for establishing the stimulus-response relationship of cultured neuronal networks.

In vitro extracellular recording and stimulation performance of nanoporous gold-modified multi-electrode arrays

NASA Astrophysics Data System (ADS)

Kim, Yong Hee; Kim, Gook Hwa; Kim, Ah Young; Han, Young Hwan; Chung, Myung-Ae; Jung, Sang-Don

2015-12-01

Objective. Nanoporous gold (Au) structures can reduce the impedance and enhance the charge injection capability of multi-electrode arrays (MEAs) used for interfacing neuronal networks. Even though there are various nanoporous Au preparation techniques, fabrication of MEA based on low-cost electro-codeposition of Ag:Au has not been performed. In this work, we have modified a Au MEA via the electro-codeposition of Ag:Au alloy, followed by the chemical etching of Ag, and report on the in vitro extracellular recording and stimulation performance of the nanoporous Au-modified MEA. Approach. Ag:Au alloy was electro-codeposited on a bilayer lift-off resist sputter-deposition passivated Au MEA followed by chemical etching of Ag to form a porous Au structure. Main results. The porous Au structure was analyzed by scanning electron microscopy and tunneling electron microscopy and found to have an interconnected nanoporous Au structure. The impedance value of the nanoporous Au-modified MEA is 15.4 ± 0.55 kΩ at 1 kHz, accompanied by the base noise V rms of 2.4 ± 0.3 μV. The charge injection limit of the nanoporous Au-modified electrode estimated from voltage transient measurement is approximately 1 mC cm-2, which is comparable to roughened platinum and carbon nanotube electrodes. The charge injection capability of the nanoporous Au-modified MEA was confirmed by observing stimulus-induced spikes at above 0.2 V. The nanoporous Au-modified MEA showed mechanical durability upon ultrasonic treatment for up to an hour. Significance. Electro-codeposition of Ag:Au alloy combined with chemical etching Ag is a low-cost process for fabricating nanoporous Au-modified MEA suitable for establishing the stimulus-response relationship of cultured neuronal networks.

Improving liquid chromatography-mass spectrometry sensitivity using a subambient pressure ionization with nanoelectrospray (SPIN) interface

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

Tang, Keqi; Page, Jason S.; Marginean, Ioan

2011-04-22

In this work the Subambient Pressure Ionization with Nanoelectrospray (SPIN) ion source and interface which operates at ~15-30 Torr is demonstrated to be compatible with gradient reversed-phase liquid chromatography-MS applications, exemplified here with the analysis of complex samples (a protein tryptic digest and a whole cell lysate). A low liquid chromatographic flow rate (100-400 nL/min) allowed stable electrospray to be established while avoiding electrical breakdown. Efforts to increase the operating pressure of the SPIN source relative to previously reported designs prevented solvent freezing and enhanced charged cluster/droplet desolvation. A 5-12-fold improvement in sensitivity relative to a conventional atmospheric pressure nanoelectrospraymore » ionization (ESI) source was obtained for detected peptides.« less

XPS and bioactivity study of the bisphosphonate pamidronate adsorbed onto plasma sprayed hydroxyapatite coatings

NASA Astrophysics Data System (ADS)

McLeod, Kate; Kumar, Sunil; Smart, Roger St. C.; Dutta, Naba; Voelcker, Nicolas H.; Anderson, Gail I.; Sekel, Ron

2006-12-01

This paper reports the use of X-ray photoelectron spectroscopy (XPS) to investigate bisphosphonate (BP) adsorption onto plasma sprayed hydroxyapatite (HA) coatings commonly used for orthopaedic implants. BPs exhibit high binding affinity for the calcium present in HA and hence can be adsorbed onto HA-coated implants to exploit their beneficial properties for improved bone growth at the implant interface. A rigorous XPS analysis of pamidronate, a commonly used nitrogenous BP, adsorbed onto plasma sprayed HA-coated cobalt-chromium substrates has been carried out, aimed at: (a) confirming the adsorption of this BP onto HA; (b) studying the BP diffusion profile in the HA coating by employing the technique of XPS depth profiling; (c) confirming the bioactivity of the adsorbed BP. XPS spectra of plasma sprayed HA-coated discs exposed to a 10 mM aqueous BP solution (pamidronate) for periods of 1, 2 and 24 h showed nitrogen and phosphorous photoelectron signals corresponding to the BP, confirming its adsorption onto the HA substrate. XPS depth profiling of the 2 h BP-exposed HA discs showed penetration of the BP into the HA matrix to depths of at least 260 nm. The bioactivity of the adsorbed BP was confirmed by the observed inhibition of osteoclast (bone resorbing) cell activity. In comparison to the HA sample, the HA sample with adsorbed BP exhibited a 25-fold decrease in primary osteoclast cells.

Computation of Reacting Flows in Combustion Processes

NASA Technical Reports Server (NTRS)

Keith, Theo G., Jr.; Chen, Kuo-Huey

1997-01-01

The main objective of this research was to develop an efficient three-dimensional computer code for chemically reacting flows. The main computer code developed is ALLSPD-3D. The ALLSPD-3D computer program is developed for the calculation of three-dimensional, chemically reacting flows with sprays. The ALL-SPD code employs a coupled, strongly implicit solution procedure for turbulent spray combustion flows. A stochastic droplet model and an efficient method for treatment of the spray source terms in the gas-phase equations are used to calculate the evaporating liquid sprays. The chemistry treatment in the code is general enough that an arbitrary number of reaction and species can be defined by the users. Also, it is written in generalized curvilinear coordinates with both multi-block and flexible internal blockage capabilities to handle complex geometries. In addition, for general industrial combustion applications, the code provides both dilution and transpiration cooling capabilities. The ALLSPD algorithm, which employs the preconditioning and eigenvalue rescaling techniques, is capable of providing efficient solution for flows with a wide range of Mach numbers. Although written for three-dimensional flows in general, the code can be used for two-dimensional and axisymmetric flow computations as well. The code is written in such a way that it can be run in various computer platforms (supercomputers, workstations and parallel processors) and the GUI (Graphical User Interface) should provide a user-friendly tool in setting up and running the code.

Ultra-Sensitive Strain Sensor Based on Flexible Poly(vinylidene fluoride) Piezoelectric Film

NASA Astrophysics Data System (ADS)

Lu, Kai; Huang, Wen; Guo, Junxiong; Gong, Tianxun; Wei, Xiongbang; Lu, Bing-Wei; Liu, Si-Yi; Yu, Bin

2018-03-01

A flexible 4 × 4 sensor array with 16 micro-scale capacitive units has been demonstrated based on flexible piezoelectric poly(vinylidene fluoride) (PVDF) film. The piezoelectricity and surface morphology of the PVDF were examined by optical imaging and piezoresponse force microscopy (PFM). The PFM shows phase contrast, indicating clear interface between the PVDF and electrode. The electro-mechanical properties show that the sensor exhibits excellent output response and an ultra-high signal-to-noise ratio. The output voltage and the applied pressure possess linear relationship with a slope of 12 mV/kPa. The hold-and-release output characteristics recover in less than 2.5 μs, demonstrating outstanding electro-mechanical response. Additionally, signal interference between the adjacent arrays has been investigated via theoretical simulation. The results show the interference reduces with decreasing pressure at a rate of 0.028 mV/kPa, highly scalable with electrode size and becoming insignificant for pressure level under 178 kPa.

Ultra-Sensitive Strain Sensor Based on Flexible Poly(vinylidene fluoride) Piezoelectric Film.

PubMed

Lu, Kai; Huang, Wen; Guo, Junxiong; Gong, Tianxun; Wei, Xiongbang; Lu, Bing-Wei; Liu, Si-Yi; Yu, Bin

2018-03-14

A flexible 4 × 4 sensor array with 16 micro-scale capacitive units has been demonstrated based on flexible piezoelectric poly(vinylidene fluoride) (PVDF) film. The piezoelectricity and surface morphology of the PVDF were examined by optical imaging and piezoresponse force microscopy (PFM). The PFM shows phase contrast, indicating clear interface between the PVDF and electrode. The electro-mechanical properties show that the sensor exhibits excellent output response and an ultra-high signal-to-noise ratio. The output voltage and the applied pressure possess linear relationship with a slope of 12 mV/kPa. The hold-and-release output characteristics recover in less than 2.5 μs, demonstrating outstanding electro-mechanical response. Additionally, signal interference between the adjacent arrays has been investigated via theoretical simulation. The results show the interference reduces with decreasing pressure at a rate of 0.028 mV/kPa, highly scalable with electrode size and becoming insignificant for pressure level under 178 kPa.

Concrete filled steel pipe inspection using electro magnetic acoustic transducer (EMAT)

NASA Astrophysics Data System (ADS)

Na, Won-Bae; Kundu, Tribikram; Ryu, Yeon-Sun; Kim, Jeong-Tae

2005-05-01

Concrete-filled steel pipes are usually exposed in hostile environments such as seawater and deicing materials. The outside corrosion of the steel pipe can reduce the wall thickness and the corrosion-induced delamination of internal concrete can increase internal volume or pressure. In addition, the void that can possibly exist in the pipe reduces the bending resistance. To avoid structural failure due to this type of deterioration, appropriate inspection and repair techniques are to be developed. Guided wave techniques have strong potentials for this kind of inspection because of long-distance inspection capability. Among different transducer-coupling mechanism, electro-magnetic acoustic transducers (EMATs) give relatively consistent results in comparison to piezoelectric transducers since they do not need any couplant. In this study EMATs are used for transmitting and receiving cylindrical guided waves through concrete-filled steel pipes. Through time history curves and wavelet transform, it is shown that EMAT-generated cylindrical guided wave techniques have good potential for the interface inspection of concrete-filled steel pipes.

Kerr electro-optic field mapping study of the effect of charge injection on the impulse breakdown strength of transformer oil

NASA Astrophysics Data System (ADS)

Zhang, X.; Zahn, M.

2013-10-01

The smart use of charge injection to improve breakdown strength in transformer oil is demonstrated in this paper. Hypothetically, bipolar homo-charge injection with reduced electric field at both electrodes may allow higher voltage operation without insulation failure, since electrical breakdown usually initiates at the electrode-dielectric interfaces. To find experimental evidence, the applicability and limitation of the hypothesis is first analyzed. Impulse breakdown tests and Kerr electro-optic field mapping measurements are then conducted with different combinations of parallel-plate aluminum and brass electrodes stressed by millisecond duration impulse. It is found that the breakdown voltage of brass anode and aluminum cathode is ˜50% higher than that of aluminum anode and brass cathode. This can be explained by charge injection patterns from Kerr measurements under a lower voltage, where aluminum and brass electrodes inject negative and positive charges, respectively. This work provides a feasible approach to investigating the effect of electrode material on breakdown strength.

Electro-hydrodynamic printing of drugs onto edible substrates

NASA Astrophysics Data System (ADS)

Shen, Yueyang; Elele, Ezinwa; Palle, Prashanth; Khusid, Boris; Basaran, Osman; McGough, Patrick T.; Collins, Robert T.

2009-11-01

While most existing drugs are manufactured as tablets using powder processing techniques, there is growing interest in printing drops containing pharmaceutical actives on edible substrates. We have developed a drop-on-demand (DOD) printing method appropriate for either replacing existing manufacturing platforms or enabling personalized medicine that overcomes the various critical challenges facing current DOD technologies. To eliminate adverse effects of electro-chemical reactions at the fluid-electrode interface, the fluid is infused into an electrically insulating nozzle to form a pendant drop that serves as a floating electrode capacitively coupled to external electrodes. A liquid bridge is formed and broken as the voltage applied at the electrode is varied in time. This gentle method for drop deposition has been demonstrated to operate with fluids spanning over three orders of magnitude in viscosity and conductivity. The proposed method has the potential for the evolving field of pharmaceutical and biomedical applications requiring the deposition of fluids at the exact locations with high volume accuracy.

Microstructural characterization of AA5183 aluminum clad AISI 1018 steel prepared by electro spark deposition

NASA Astrophysics Data System (ADS)

Rastkerdar, E.; Aghajani, H.; Kianvash, A.; Sorrell, C. C.

2018-04-01

The application of a simple and effective technique, electro spark deposition (ESD), to create aluminum clad steel plate has been studied. AA5183 aluminum rods were used as the rotating electrode for cladding of the AISI 1018 steel. The microstructure of the interfacial zone including the intermetallic compounds (IMC) layer and the clad metal have been investigated by scanning electron microscopy (SEM) equipped with energy dispersive spectroscopy (EDS) and transmission electron microscopy (TEM and STEM). According to the results sound aluminum clad with thickness up to 25–30 μm can be achieved. Very thin (<4 μm) IMC layer was formed at the Al/Fe interface and the structural (electron diffraction pattern) and chemical analysis (STEM) conducted by TEM confirmed that the layer is constituted of Fe rich phases, both implying a much improved mechanical properties. Investigation of the orientations of phases at the interfacial zone confirmed absence of any preferred orientation.

Electro-coalescence of particle-coated droplets

NASA Astrophysics Data System (ADS)

Shum, Anderson Ho Cheung

Droplets in air or in an immiscible liquid phase are used widely in applications ranging from personal hygiene products to drug delivery. The stability of the droplets are highly linked to their utility, and thus have been systematically studied. To enhance the stability of the droplets, particles are often added to the droplets. In this talk, I will discuss how the particle layer at droplet interfaces responds to electrical charging of the droplets. The electrical forces can distort the droplet shape, which is opposed by the layer of particles adsorbed. A balance of the electrical and interfacial effects provides a quantitative indicator of the droplet instability. The coalescence of droplets in both air and liquid induced by electrically charging, which we call ``electro-coalescence'', will be introduced, with its potential application in devising a digital millifluidic platform. We thank the Research Grants Council of Hong Kong (No. HKU 719813E, 17304514 and 17306315 and C6004-14G) from the and National Natural Science Foundation of China (No. 21476189/B060201 and 91434202).

Tailoring chain length and cross-link density in dielectric elastomer toward enhanced actuation strain

NASA Astrophysics Data System (ADS)

Zhang, Quan-Ping; Liu, Jun-Hua; Liu, Hai-Dong; Jia, Fei; Zhou, Yuan-Lin; Zheng, Jian

2017-10-01

Adding ceramic or conductive fillers into polymers for increasing permittivity is a direct and effective approach to enhance the actuation strain of dielectric elastomer actuators (DEAs). Unfortunately, the major dielectric loss caused by weak interfaces potentially harms the electro-mechanical stability and lifetime of DEAs. Here, we construct a desired macromolecular network with a long chain length and low cross-link density to reduce the elastic modulus of silicone elastomers. Selecting a high molecular weight of polymethylvinylsiloxane and a low dose of the cross-linker leads the soft but tough networks with rich entanglements, poor cross-links, and a low amount of defects. Then, a ductile material with low elastic modulus but high elongation at break is obtained. It accounts for much more excellent actuation strain of Hl in comparison to that of the other silicone elastomers. Importantly, without other fillers, the ultralow dielectric loss, conductivity, and firm networks possibly promote the electro-mechanical stability and lifetime for the DEA application.

Giant Pockels effect in ZnO-F films deposited on bare glasses

NASA Astrophysics Data System (ADS)

Kityk, I. V.; Ebothe, J.; El Hichou, A.; Addou, M.; Bougrine, A.; Sahraoui, B.

2002-06-01

A giant linear electro-optics (Pockels) effect (up to 17 pm V-1) (for wavelength about 435 nm) in ZnO crystalline films doped with fluorine and deposited on bare glass has been found. For description of the observed phenomenon, a complex approach including self-consistent band structure calculations together with an appropriate molecular dynamics simulation of the interface structure was applied. Experimental ellipsometric and refractive index measurements confirm an efficiency of the mentioned approach for description of the observed interface (between the film and glass) processes. The origin of the observed effect is caused by substantial non-centrosymmetric charge density distribution between the ZnO wurtzite-like crystalline films and the bare glass substrate, as well as by additional charge density polarization caused by fluorine atoms.

Structural Characterization of Core Region in Erwinia amylovora Lipopolysaccharide.

PubMed

Casillo, Angela; Ziaco, Marcello; Lindner, Buko; Merino, Susana; Mendoza-Barberá, Elena; Tomás, Juan M; Corsaro, Maria Michela

2017-03-04

Erwinia amylovora ( E. amylovora ) is the first bacterial plant pathogen described and demonstrated to cause fire blight, a devastating plant disease affecting a wide range of species including a wide variety of Rosaceae . In this study, we reported the lipopolysaccharide (LPS) core structure from E. amylovora strain CFBP1430, the first one for an E. amylovora highly pathogenic strain. The chemical characterization was performed on the mutants waaL (lacking only the O-antigen LPS with a complete LPS-core), wabH and wabG (outer-LPS core mutants). The LPSs were isolated from dry cells and analyzed by means of chemical and spectroscopic methods. In particular, they were subjected to a mild acid hydrolysis and/or a hydrazinolysis and investigated in detail by one and two dimensional Nuclear Magnetic Resonance (NMR) spectroscopy and ElectroSpray Ionization Fourier Transform-Ion Cyclotron Resonance (ESI FT-ICR) mass spectrometry.

Infrared photodissociation spectroscopy of protonated neurotransmitters in the gas phase

NASA Astrophysics Data System (ADS)

MacLeod, N. A.; Simons, J. P.

2007-03-01

Protonated neurotransmitters have been produced in the gas phase via a novel photochemical scheme: complexes of the species of interest, 1-phenylethylamine, 2-amino-1-phenylethanol and the diastereo-isomers, ephedrine and pseudoephedrine, with a suitable proton donor, phenol (or indole), are produced in a supersonic expansion and ionized by resonant two photon ionization of the donor. Efficient proton transfer generates the protonated neurotransmitters, complexed to a phenoxy radical. Absorption of infrared radiation, and subsequent evaporation of the phenoxy tag, coupled with time of flight mass spectrometry, provides vibrational spectra of the protonated (and also hydrated) complexes for comparison with the results of quantum chemical computation. Comparison with the conformational structures of the neutral neurotransmitters (established previously) reveals the effect of protonation on their structure. The photochemical proton transfer strategy allows spectra to be recorded from individual laser shots and their quality compares favourably with that obtained using electro-spray or matrix assisted laser desorption ion sources.

Electrodeposited MCrAlY Coatings for Gas Turbine Engine Applications

NASA Astrophysics Data System (ADS)

Zhang, Y.

2015-11-01

Electrolytic codeposition is a promising alternative process for fabricating MCrAlY coatings. The coating process involves two steps, i.e., codeposition of CrAlY-based particles and a metal matrix of Ni, Co, or (Ni,Co), followed by a diffusion heat treatment to convert the composite coating to the desired MCrAlY microstructure. Despite the advantages such as low cost and non-line-of-sight, this coating process is less known than electron beam-physical vapor deposition and thermal spray processes for manufacturing high-temperature coatings. This article provides an overview of the electro-codeposited MCrAlY coatings for gas turbine engine applications, highlighting the unique features of this coating process and some important findings in the past 30 years. Challenges and research opportunities for further optimization of this type of MCrAlY coatings are also discussed.

Bio-Decontamination of Water and Surfaces by DC Discharges in Atmospheric Air

NASA Astrophysics Data System (ADS)

Machala, Zdenko; Tarabová, Barbora; Pelach, Michal; Šipoldová, Zuzana; Hensel, Karol; Janda, Mário; Šikurová, Libuša

Two types of DC-driven atmospheric air discharges, including a streamer corona and a transient spark with short high current pulses of limited energy, were employed for bio-decontamination of water and various surfaces (agar plates, plastic foils, human teeth) contaminated by bacteria or spores (Salmonella typhimurium, Bacillus cereus). Both discharges generate cold non-equilibrium plasma. The discharges combined with the electro-spraying of the treated water through the needle electrode lead to fast and efficient bio-decontamination. Experiments comparing direct and indirect plasma effects, oxidation stress measurements in the cell membranes, and chemical changes induced in the treated water enable assessment of the plasma agents being responsible for microbial inactivation. Radicals and reactive oxygen species seem to be dominant biocidal agents, although deeper understanding of the plasma-induced water chemistry and of the temporal evolution of the bio-inactivation processes is needed.

Electrospraying and Electrospinning of Polymers for Biomedical Applications. Poly(Lactic-Co-Glycolic Acid) and Poly(Ethylene-Co-Vinylacetate). Appendix 2

NASA Technical Reports Server (NTRS)

Stitzel, Joel D.; Bowlin, Gary L.; Mansfield, Kevin; Wnek, Gary E.; Simpson, David G.

2000-01-01

Significant opportunities exist for the processing of polymers (homopolymers and blends) using electric fields. Specific attention is given here to electrospinning, but we note that electroaerosol formation and field-modulated film casting represent additional processing options. Of particular interest is the ability to generate polymer fibers of sub-micron dimensions using electrospinning, down to about 0.05 microns (50 nm), a size range that has been traditionally difficult to access. In our work, poly(lactic-co-glycolic acid), PLA/PGA, poly(lactic acid) PLA, and poly(ethylene-co-vinylacetate) (PEVA) have been deposited from solutions in methylene chloride or chloroform by electrospraying or electrospinning to afford morphologically tailored materials for tissue engineering and related applications. Low solution concentrations tend to favor electrostatic spraying ('electro-aerosolization') while higher concentrations lead to spinning on fibrous mats. Preliminary observations of muscle cell growth on PLA electrospun mats are reported.

Au-embedded ZnO/NiO hybrid with excellent electrochemical performance as advanced electrode materials for supercapacitor.

PubMed

Zheng, Xin; Yan, Xiaoqin; Sun, Yihui; Bai, Zhiming; Zhang, Guangjie; Shen, Yanwei; Liang, Qijie; Zhang, Yue

2015-02-04

Here we design a nanostructure by embedding Au nanoparticles into ZnO/NiO core-shell composites as supercapacitors electrodes materials. This optimized hybrid electrodes exhibited an excellent electrochemical performance including a long-term cycling stability and a maximum specific areal capacitance of 4.1 F/cm(2) at a current density of 5 mA/cm(2), which is much higher than that of ZnO/NiO hierarchical materials (0.5 F/cm(2)). Such an enhanced property is attributed to the increased electro-electrolyte interfaces, short electron diffusion pathways and good electrical conductivity. Apart from this, electrons can be temporarily trapped and accumulated at the Fermi level (EF') because of the localized schottky barrier at Au/NiO interface in charge process until fill the gap between ZnO and NiO, so that additional electrons can be released during discharge. These results demonstrate that suitable interface engineering may open up new opportunities in the development of high-performance supercapacitors.

Quantification, dissipation behavior and risk assessment of ethion in green pea by gas chromatography-electron capture detector.

PubMed

Jan, Ishrat; Dar, Alamgir A; Mubashir, Sofi; Alam Wani, Ashraf; Mukhtar, Malik; Sofi, Khurshid A; Dar, Irshad H; Sofi, Javid A

2018-05-01

Residue investigation was carried out to scrutinize the persistence, dissipation behavior, half-life, and risk assessment of ethion on green pea fruit by spraying ethion at the fruiting stage followed by another application at 10 day intervals. The samples were extracted by using a quick, easy, low-cost, effective, rugged, and safe method, and the residues of ethion were analyzed by gas chromatography with electron capture detection. Here we report a novel, accurate, and cost-effective gas chromatography method for the determination of average deposits of ethion on green pea. The initial deposits were found to be 4.65 mg/kg following the application of insecticide. Residues of ethion reached below the detection limit of 0.10 mg/kg after 25 days at recommended dosage. The half-life of ethion was found to be 4.62 days. For risk assessment studies, the 25th day will be safe for consumers for the consumption of green peas. The developed method is simple, sensitive, selective, and repeatable and can be extended for ethion-based standardization of herbal formulations containing green pea and its use in pesticide industries. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Risk assessment, dissipation behavior and persistence of quinalphos in/on green pea by gas chromatography with electron capture detector.

PubMed

Dar, Alamgir A; Jan, Ishrat; Wani, Ashraf A; Mubashir, Sofi; Sofi, Khurshid A; Sofi, Javid A; Dar, Irshad H

2018-06-01

Chemical investigation was carried out to examine the risk assessment, dissipation behavior, persistence, and half-life period of quinalphos in/on green pea fruit by spraying quinalphos at fruiting stage followed by another application after 10-day interval. The samples were extracted by using the quick, easy, cheap, effective, rugged, and safe method, and the residues of quinalphos were analyzed by gas chromatography with electron capture detector. Herein, we report a novel, accurate, and cost-effective gas chromatography method for the determination of average deposits of quinalphos in/on green pea. The initial deposits and half-life of quinalphos were found to be 1.20 mg/kg and 2.77 days, respectively, following the application of insecticide. Residues of quinalphos reached below detection limit of 0.05 mg/kg after 10 days at recommended dosage. For risk assessment studies, the tenth day will be safe for consumers for consumption of green pea. The developed method is simple, selective, and repeatable, and it can be extended for quinalphos-based standardization of herbal formulations containing green pea and its use in pesticide industries. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Thermal Fatigue and Fracture Behavior of Ceramic Thermal Barrier Coatings

NASA Technical Reports Server (NTRS)

Zhu, Dong-Ming; Choi, Sung R.; Miller, Robert A.

2001-01-01

Thermal fatigue and fracture behavior of plasma-sprayed ceramic thermal barrier coatings has been investigated under high heat flux and thermal cyclic conditions. The coating crack propagation is studied under laser heat flux cyclic thermal loading, and is correlated with dynamic fatigue and strength test results. The coating stress response and inelasticity, fatigue and creep interactions, and interface damage mechanisms during dynamic thermal fatigue processes are emphasized.

Effect of the temperature on the spray drying of Roselle extracts (Hibiscus sabdariffa L.).

PubMed

Gonzalez-Palomares, Salvador; Estarrón-Espinosa, Mirna; Gómez-Leyva, Juan Florencio; Andrade-González, Isaac

2009-03-01

The effect of the drying temperature on the volatile components and sensory acceptance of the Roselle (Hibiscus sabdariffa) extract in powder was investigated. The Roselle extraction was carried out by maceration with 7 L of 30% ethanol (v/v), 560 g of fresh Roselle calyces for 168 h. The Roselle extracts were spray dried at different temperatures 150, 160, 170, 180, 190, 200 and 210 degrees C, giving different outlet values about yield and final moisture. The volatile compounds in Roselle extract and dried samples were performed using needles of solid phase microextraction (SPME) and gas chromatography/mass spectrometry (GC/MS HP-5890). Twenty volatile compounds were identified in the extracts among them terpenoids, esters, hydrocarbons and aldehydes. Fourteen volatile compounds were identified in the powder sample, but only ten were present in the Roselle extract. This indicates that some compounds were lost and some others were generated due to a degradation process. An acceptability sensory analysis showed that the best powder sample was the Roselle extract dehydrated using temperature between 190 degrees C and 200 degrees C (p<0.05). There was not statistically significant difference in the pH of Roselle extracts ranging from 3.4 to 3.9. It was concluded that the spray drying temperature of the Roselle extracts has an effect on the volatile compounds losses.

Use of a double condenser in a dehumidifier with a spray dryer for vitamin A extraction in tomato as a heat-sensitive material

NASA Astrophysics Data System (ADS)

Kosasih, E. A.; Warjito, H., Imansyah I.; Ruhyat, N.

2017-06-01

Spray dryers are commonly operated at a high temperature (>100 °C), which becomes an obstacle for heat-sensitive materials. In this study, a refrigeration system that uses evaporator as dehumidifier and that recovers the heat released from the first condenser to preheat the drying air was utilised to reduce the drying temperature. Results showed that the degradation of vitamin A (measured with the high performance liquid chromatography method) in tomato increased significantly when the drying air temperature increased from 90 °C to 120 °C, and it cannot be controlled at a temperature higher than 120 °C. At an air flow rate of 450 lpm, the drying capacity at a drying air temperature of 60 °C (with refrigeration, humidity ratio of 0.005 [kg H2O / kg dry air]) is equal to the drying capacity at a drying air temperature of 120 °C (without refrigeration, humidity ratio of 0.021 [kg H2O / kg dry air]). The drying capacity at a drying air temperature of 90 °C (with refrigeration) even becomes 1.5 times the drying capacity at a drying air temperature of 120 °C (without refrigeration). The combination of a spray dryer system with a refrigeration system (double condenser) is therefore beneficial for drying heat-sensitive materials, such as vitamin A.

Analysis of Plasma-Sprayed Thermal Barrier Coatings With Homogeneous and Heterogeneous Bond Coats Under Spatially Uniform Cyclic Thermal Loading

NASA Technical Reports Server (NTRS)

Arnold, Steven M.; Pindera, Marek-Jerzy; Aboudi, Jacob

2003-01-01

This report summarizes the results of a numerical investigation into the spallation mechanism in plasma-sprayed thermal barrier coatings observed under spatially-uniform cyclic thermal loading. The analysis focuses on the evolution of local stress and inelastic strain fields in the vicinity of the rough top/bond coat interface during thermal cycling, and how these fields are influenced by the presence of an oxide film and spatially uniform and graded distributions of alumina particles in the metallic bond coat aimed at reducing the top/bond coat thermal expansion mismatch. The impact of these factors on the potential growth of a local horizontal delamination at the rough interface's crest is included. The analysis is conducted using the Higher-Order Theory for Functionally Graded Materials with creep/relaxation constituent modeling capabilities. For two-phase bond coat microstructures, both the actual and homogenized properties are employed in the analysis. The results reveal the important contributions of both the normal and shear stress components to the delamination growth potential in the presence of an oxide film, and suggest mixed-mode crack propagation. The use of bond coats with uniform or graded microstructures is shown to increase the potential for delamination growth by increasing the magnitude of the crack-tip shear stress component.

Carbon nanotube reinforced aluminum based nanocomposite fabricated by thermal spray forming

NASA Astrophysics Data System (ADS)

Laha, Tapas

The present research concentrates on the fabrication of bulk aluminum matrix nanocomposite structures with carbon nanotube reinforcement. The objective of the work was to fabricate and characterize multi-walled carbon nanotube (MWCNT) reinforced hypereutectic Al-Si (23 wt% Si, 2 wt% Ni, 1 wt% Cu, rest Al) nanocomposite bulk structure with nanocrystalline matrix through thermal spray forming techniques viz. plasma spray forming (PSF) and high velocity oxy-fuel (HVOF) spray forming. This is the first research study, which has shown that thermal spray forming can be successfully used to synthesize carbon nanotube reinforced nanocomposites. Microstructural characterization based on quantitative microscopy, scanning and transmission electron microscopy (SEM and TEM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), Raman spectroscopy and X ray photoelectron spectroscopy (XPS) confirms (i) retention and macro/sub-macro level homogenous distribution of multiwalled carbon nanotubes in the Al-Si matrix and (ii) evolution of nanostructured grains in the matrix. Formation of ultrathin beta-SiC layer on MWCNT surface, due to chemical reaction of Si atoms diffusing from Al-Si alloy and C atoms from the outer walls of MWCNTs has been confirmed theoretically and experimentally. The presence of SiC layer at the interface improves the wettability and the interfacial adhesion between the MWCNT reinforcement and the Al-Si matrix. Sintering of the as-sprayed nanocomposites was carried out in an inert environment for further densification. As-sprayed PSF nanocomposite showed lower microhardness compared to HVOF, due to the higher porosity content and lower residual stress. The hardness of the nanocomposites increased with sintering time due to effective pore removal. Uniaxial tensile test on CNT-bulk nanocomposite was carried out, which is the first ever study of such nature. The tensile test results showed inconsistency in the data attributed to inhomogeneous microstructure and limitation of the test samples geometry. The elastic moduli of nanocomposites were computed using different micromechanics models and compared with experimentally measured values. The elastic moduli of nanocomposites measured by nanoindentation technique, increased gradually with sintering attributed to porosity removal. The experimentally measured values conformed better with theoretically predicted values, particularly in the case of Hashin-Shtrikman bound method.

Evaluation of a direct injection nebulizer interface for flow injection analysis and high performance liquid chromatography with inductively coupled plasma-atomic emission spectroscopic detection

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

LaFreniere, K.E.

A direct injection nebulizer (DIN) was designed, developed, and evaluated to determine its potential utilization as an effective interface for flow injection analysis (FIA) and high performance liquid chromatography (HPLC) coupled with inductively coupled plasma-atomic emission spectroscopic detection. The analytical figures of merit for the DIN when used as an interface for FIA-ICP-AES were found to be comparable to or better than those obtained with conventional pneumatic nebulization in terms of limits of detection (LODs), reproducibility, linearity, and interelement effects. Stable plasma operation was maintained for the DIN sample introduction of a variety of pure organic solvents, including acetonitrile, methanol,more » methylisobutylketone, and pyridine. The HPLC-DIN-ICP-AES facility was specifically applied for the speciation of inorganic and organometallic species contained in synthetic mixtures, vanilla extracts, and a variety of energy-related materials, such as shale oil process water, coal extracts, shale oil, crude oil, and an SRC II. Suggestions for future research are also considered. 227 refs., 44 figs., 15 tabs.« less

Passive Wireless Hermetic Environment Monitoring System for Spray Painting Workshop

PubMed Central

Wang, Lifeng; Ma, Jingjing; Huang, Yan; Tang, Dan; Huang, Qing-An

2016-01-01

Passive wireless sensors have the advantages of operating without a power supply and remote sensing capability. Hence, they are very suitable for some harsh environments, such as hermetic environments, rotating parts, or very high temperature environments. The spray painting workshop is such a harsh environment, containing a large amount of flammable paint mist and organic gas. Aiming at this special environment of spray painting workshop, a passive wireless hermetic environment monitoring system was designed, fabricated, and demonstrated. The proposed system is composed of a transponder and a reader, and the circuit design of each part is given in detail in this paper. The power and the data transmission between the transponder and the reader are realized by the inductive coupling mechanism. Utilizing the back scatter modulation and channel multiplexing, the frequency signals generated by three different environmental sensors—together with their interfaces in the transponder—are wirelessly read out by the reader. Because of the harsh environment of the spray painting room, the package of the monitoring system is quite important. Three different kinds of filter films for the system package were compared. The experimental results show that the composite filter film aluminum anodic oxide/polytetrafluoroethylene (AAO/PTFE) has the best performance. After fabrication, the measured temperature, humidity, and pressure sensitivities were measured and found to be 180 Hz/°C in the range of 0~60 °C, 100 Hz/%RH in the range of 15~95 %RH, and 42 Hz/hPa in the range of 600~1100 hPa, respectively. Additionally, the remote sensing distance of the monitoring system reaches 4 cm. Finally, the passive wireless hermetic environment monitoring system was installed on the glass wall of the spray painting workshop and was successfully demonstrated. PMID:27490546

A Eulerian-Lagrangian Model to Simulate Two-Phase/Particulate Flows

NASA Technical Reports Server (NTRS)

Apte, S. V.; Mahesh, K.; Lundgren, T.

2003-01-01

Figure 1 shows a snapshot of liquid fuel spray coming out of an injector nozzle in a realistic gas-turbine combustor. Here the spray atomization was simulated using a stochastic secondary breakup model (Apte et al. 2003a) with point-particle approximation for the droplets. Very close to the injector, it is observed that the spray density is large and the droplets cannot be treated as point-particles. The volume displaced by the liquid in this region is significant and can alter the gas-phase ow and spray evolution. In order to address this issue, one can compute the dense spray regime by an Eulerian-Lagrangian technique using advanced interface tracking/level-set methods (Sussman et al. 1994; Tryggvason et al. 2001; Herrmann 2003). This, however, is computationally intensive and may not be viable in realistic complex configurations. We therefore plan to develop a methodology based on Eulerian-Lagrangian technique which will allow us to capture the essential features of primary atomization using models to capture interactions between the fluid and droplets and which can be directly applied to the standard atomization models used in practice. The numerical scheme for unstructured grids developed by Mahesh et al. (2003) for incompressible flows is modified to take into account the droplet volume fraction. The numerical framework is directly applicable to realistic combustor geometries. Our main objectives in this work are: Develop a numerical formulation based on Eulerian-Lagrangian techniques with models for interaction terms between the fluid and particles to capture the Kelvin- Helmholtz type instabilities observed during primary atomization. Validate this technique for various two-phase and particulate flows. Assess its applicability to capture primary atomization of liquid jets in conjunction with secondary atomization models.

NASA Tech Briefs, October 2013

NASA Technical Reports Server (NTRS)

2013-01-01

Topics include: A Short-Range Distance Sensor with Exceptional Linearity; Miniature Trace Gas Detector Based on Microfabricated Optical Resonators; Commercial Non-Dispersive Infrared Spectroscopy Sensors for Sub-Ambient Carbon Dioxide Detection; Fast, Large-Area, Wide-Bandgap UV Photodetector for Cherenkov Light Detection; Mission Data System Java Edition Version 7; Adaptive Distributed Environment for Procedure Training (ADEPT); LEGEND, a LEO-to-GEO Environment Debris Model; Electronics/Computers; Millimeter-Wave Localizers for Aircraft-to-Aircraft Approach Navigation; Impedance Discontinuity Reduction Between High-Speed Differential Connectors and PCB Interfaces; SpaceCube Version 1.5; High-Pressure Lightweight Thrusters; Non-Magnetic, Tough, Corrosion- and Wear-Resistant Knives From Bulk Metallic Glasses and Composites; Ambient Dried Aerogels; Applications for Gradient Metal Alloys Fabricated Using Additive Manufacturing; Passivation of Flexible YBCO Superconducting Current Lead With Amorphous SiO2 Layer; Propellant-Flow-Actuated Rocket Engine Igniter; Lightweight Liquid Helium Dewar for High-Altitude Balloon Payloads; Method to Increase Performance of Foil Bearings Through Passive Thermal Management; Unibody Composite Pressurized Structure; JWST Integrated Science Instrument Module Alignment Optimization Tool; Radar Range Sidelobe Reduction Using Adaptive Pulse Compression Technique; Digitally Calibrated TR Modules Enabling Real-Time Beamforming SweepSAR Architectures; Electro-Optic Time-to-Space Converter for Optical Detector Jitter Mitigation; Partially Transparent Petaled Mask/Occulter for Visible-Range Spectrum; Educational NASA Computational and Scientific Studies (enCOMPASS); Coarse-Grain Bandwidth Estimation Scheme for Large-Scale Network; Detection of Moving Targets Using Soliton Resonance Effect; High-Efficiency Nested Hall Thrusters for Robotic Solar System Exploration; High-Voltage Clock Driver for Photon-Counting CCD Characterization; Development of the Code RITRACKS; and Enabling Microliquid Chromatography by Microbead Packing of Microchannels.

Qualitative and quantitative two-dimensional thin-layer chromatography/high performance liquid chromatography/diode-array/electrospray-ionization-time-of-flight mass spectrometry of cholinesterase inhibitors.

PubMed

Mroczek, Tomasz

2016-09-10

Recently launched thin-layer chromatography-mass spectrometry (TLC-MS) interface enabling extraction of compounds directly from TLC plates into MS ion source was unusually extended into two-dimensional thin-layer chromatography/high performance liquid chromatography (2D, TLC/HPLC) system by its a direct connection to a rapid resolution 50×2.1mm, I.D. C18 column compartment followed by detection by diode array (DAD) and electrospray ionisation time-of-flight mass spectrometry (ESI-TOF-MS). In this way, even not separated bands of complicated mixtures of natural compounds could be analysed structurally, only within 1-2min after development of TLC plates. In comparison to typically applied TLC-MS interface, no ion suppression for acidic mobile phases was observed. Also, substantial increase in ESI-TOF-MS sensitivities and quality of spectra, were noticed. It has been utilised in combination with TLC- based bioautographic approaches of acetylcholinesterase (AChE) inhibitors, However, it can be also applied in any other procedures related to bioactivity (e.g. 2,2-Diphenyl-1-picryl-hydrazyl-DPPH screen test for radicals). This system has been also used for determination of half maximal inhibitory concentration (IC50 values) of the active inhibitor-galanthamine, as an example. Moreover, AChE inhibitory potencies of some of purified plant extracts, never studied before, have been quantitatively measured. This is first report of usage such the 2D TLC/HPLC/MS system both for qualitative and quantitative evaluation of cholinesterase inhibitors in biological matrices. Copyright © 2016 Elsevier B.V. All rights reserved.

Determination of low-level acrylamide in drinking water by liquid chromatography/tandem mass spectrometry.

PubMed

Lucentini, Luca; Ferretti, Emanuele; Veschetti, Enrico; Achene, Laura; Turrio-Baldassarri, Luigi; Ottaviani, Massimo; Bogialli, Sara

2009-01-01

A simple and sensitive liquid chromatographic-tandem mass spectrometric (LC/MS/MS) method has been developed and validated to confirm and quantify acrylamide monomer (AA) in drinking water using [13C3] acrylamide as internal standard (IS). After a preconcentration by solid-phase extraction with spherical activated carbon, analytes were chromatographed on IonPac ICE-AS1 column (9 x 250 mm) under isocratic conditions using acetonitrile-water-0.1 M formic acid (43 + 52 + 5, v/v/v) as the mobile phase. Analysis was achieved using a triple-quadrupole mass analyzer equipped with a turbo ion spray interface. For confirmation and quantification of the analytes, MS data acquisition was performed in the multireaction monitoring mode, selecting 2 precursor ion to product ion transitions for both AA and IS. The method was validated for linearity, sensitivity, accuracy, precision, extraction efficiency, and matrix effect. Linearity in tap water was observed over the concentration range 0.1-2.0 microg/L. Limits of detection and quantification were 0.02 and 0.1 microg/L, respectively. Interday and intraday assays were performed across 3 validation levels (0.1, 0.5, and 1.5 microg/L). Accuracy (as mean recovery) ranged from 89.3 to 96.2% with relative standard deviation <7.98%. Performance characteristics of this LC/MS/MS method make it suitable for regulatory confirmatory analysis of AA in drinking water in compliance with European Union and U.S. Environmental Protection Agency standards.

Investigation of Air-Liquid Interface Rings in Buffer Preparation Vessels: the Role of Slip Agents.

PubMed

Shi, Ting; Ding, Wei; Kessler, Donald W; De Mas, Nuria; Weaver, Douglas G; Pathirana, Charles; Martin, Russell D; Mackin, Nancy A; Casati, Michael; Miller, Scott A; Pla, Itzcoatl A

2016-01-01

Air-liquid interface rings were observed on the side walls of stainless steel buffer vessels after certain downstream buffer preparations. Those rings were resistant to regular cleaning-in-place procedures but could be removed by manual means. To investigate the root cause of this issue, multiple analytical techniques, including liquid chromatography with tandem mass spectrometry detection (LC-MS/MS), high-resolution accurate mass liquid chromatography with mass spectrometry, nuclear magnetic resonance, Fourier transform infrared spectroscopy, and scanning electron microscopy with energy-dispersive X-ray spectroscopy have been employed to characterize the chemical composition of air-liquid interface rings. The main component of air-liquid interface rings was determined to be slip agents, and the origin of the slip agents can be traced back to their presence on raw material packaging liners. Slip agents are commonly used in plastic industry as additives to reduce the coefficient of friction during the manufacturing process of thin films. To mitigate this air-liquid interface ring issue, an alternate liner with low slip agent was identified and implemented with minimal additional cost. We have also proactively tested the packaging liners of other raw materials currently used in our downstream buffer preparation to ensure slip agent levels are appropriate. Air-liquid interface rings were observed on the side walls of stainless steel buffer vessels after certain downstream buffer preparations. To investigate the root cause of this issue, multiple analytical techniques have been employed to characterize the chemical composition of air-liquid interface rings. The main components of air-liquid interface rings were determined to be slip agents, which are common additives used in the manufacturing process of thin films. The origin of the slip agents can be traced back to their presence on certain raw material packaging liners. To mitigate this air-liquid interface ring issue, an alternate liner with low slip agent was identified and implemented. © PDA, Inc. 2016.

Performance Assessment of a Humidity Measurement System and Its Use to Evaluate Moisture Characteristics of Wheelchair Cushions at the User–Seat Interface

PubMed Central

Liu, Zhuofu; Cheng, Haifeng; Luo, Zhongming; Cascioli, Vincenzo; Heusch, Andrew I.; Nair, Nadia R.; McCarthy, Peter W.

2017-01-01

Little is known about the changes in moisture that occur at the body–seat interface during sitting. However, as increased moisture can add to the risk of skin damage, we have developed an array of MEMS (Micro-Electro-Mechanical System) humidity sensors to measure at this interface. Sensors were first evaluated against traceable standards, followed by use in a cross-over field test (n = 11; 20 min duration) using different wheelchair cushions (foam and gel). Relative humidity (RH) was measured at the left mid-thigh, right mid-thigh and coccyx. Sensors were shown to be unaffected by loading and showed highly reliable responses to measured changes in humidity, varying little from the traceable standard (<5%). Field-test data, smoothed through a moving average filter, revealed significant differences between the three chosen locations and between the gel and foam cushions. Maximum RH was attained in less than five minutes regardless of cushion material (foam or gel). Importantly, RH does not appear to distribute uniformly over the body–seat interface; suggesting multiple sensor positions would appear essential for effectively monitoring moisture in this interface. Material properties of the cushions appear to have a significant effect on RH characteristics (profile) at the body–seat interface, but not necessarily the time to peak moisture. PMID:28379165

Efficacy of brain-computer interface-driven neuromuscular electrical stimulation for chronic paresis after stroke.

PubMed

Mukaino, Masahiko; Ono, Takashi; Shindo, Keiichiro; Fujiwara, Toshiyuki; Ota, Tetsuo; Kimura, Akio; Liu, Meigen; Ushiba, Junichi

2014-04-01

Brain computer interface technology is of great interest to researchers as a potential therapeutic measure for people with severe neurological disorders. The aim of this study was to examine the efficacy of brain computer interface, by comparing conventional neuromuscular electrical stimulation and brain computer interface-driven neuromuscular electrical stimulation, using an A-B-A-B withdrawal single-subject design. A 38-year-old male with severe hemiplegia due to a putaminal haemorrhage participated in this study. The design involved 2 epochs. In epoch A, the patient attempted to open his fingers during the application of neuromuscular electrical stimulation, irrespective of his actual brain activity. In epoch B, neuromuscular electrical stimulation was applied only when a significant motor-related cortical potential was observed in the electroencephalogram. The subject initially showed diffuse functional magnetic resonance imaging activation and small electro-encephalogram responses while attempting finger movement. Epoch A was associated with few neurological or clinical signs of improvement. Epoch B, with a brain computer interface, was associated with marked lateralization of electroencephalogram (EEG) and blood oxygenation level dependent responses. Voluntary electromyogram (EMG) activity, with significant EEG-EMG coherence, was also prompted. Clinical improvement in upper-extremity function and muscle tone was observed. These results indicate that self-directed training with a brain computer interface may induce activity- dependent cortical plasticity and promote functional recovery. This preliminary clinical investigation encourages further research using a controlled design.

Performance Assessment of a Humidity Measurement System and Its Use to Evaluate Moisture Characteristics of Wheelchair Cushions at the User-Seat Interface.

PubMed

Liu, Zhuofu; Cheng, Haifeng; Luo, Zhongming; Cascioli, Vincenzo; Heusch, Andrew I; Nair, Nadia R; McCarthy, Peter W

2017-04-05

Little is known about the changes in moisture that occur at the body-seat interface during sitting. However, as increased moisture can add to the risk of skin damage, we have developed an array of MEMS (Micro-Electro-Mechanical System) humidity sensors to measure at this interface. Sensors were first evaluated against traceable standards, followed by use in a cross-over field test ( n = 11; 20 min duration) using different wheelchair cushions (foam and gel). Relative humidity (RH) was measured at the left mid-thigh, right mid-thigh and coccyx. Sensors were shown to be unaffected by loading and showed highly reliable responses to measured changes in humidity, varying little from the traceable standard (<5%). Field-test data, smoothed through a moving average filter, revealed significant differences between the three chosen locations and between the gel and foam cushions. Maximum RH was attained in less than five minutes regardless of cushion material (foam or gel). Importantly, RH does not appear to distribute uniformly over the body-seat interface; suggesting multiple sensor positions would appear essential for effectively monitoring moisture in this interface. Material properties of the cushions appear to have a significant effect on RH characteristics (profile) at the body-seat interface, but not necessarily the time to peak moisture.

Particle Engulfment and Pushing by Solidifying Interfaces

NASA Technical Reports Server (NTRS)

Stefanescu, D. M.; Mukherjee, S.; Juretzko, F. R.; Catalina, A. V.; Sen, S.; Curreri, P. A.

2000-01-01

The phenomenon of interaction of particles with solid-liquid interfaces (SLI) has been studied since mid 1960's. While the original interest stemmed from geology applications (frost heaving in soil), researchers soon realized that fundamental understanding of particles behavior at solidifying interfaces might yield practical benefits in other fields, including metallurgy. In materials engineering the main issue is the location of particles with respect to grain boundaries at the end of solidification. Considerable experimental and theoretical research was lately focused on applications to metal matrix composites produced by casting or spray forming techniques, and on inclusion management in steel. Another application of particle SLI interaction is in the growing of Y1Ba2Cu3O(7-delta) (123) superconductor crystals from an undercooled liquid. The oxide melt contains Y2Ba1Cu1O5 (211) precipitates, which act as flux pinning sites.

Detection and Characterization of Flaws in Sprayed on Foam Insulation with Pulsed Terahertz Frequency Electromagnetic Waves

NASA Technical Reports Server (NTRS)

Winfree, William P.; Madaras, Eric I.

2005-01-01

The detection and repair of flaws such as voids and delaminations in the sprayed on foam insulation of the external tank reduces the probability of foam debris during shuttle ascent. The low density of sprayed on foam insulation along with it other physical properties makes detection of flaws difficult with conventional techniques. An emerging technology that has application for quantitative evaluation of flaws in the foam is pulsed electromagnetic waves at terahertz frequencies. The short wavelengths of these terahertz pulses make them ideal for imaging flaws in the foam. This paper examines the application of terahertz pulses for flaw detection in foam characteristic of the foam insulation of the external tank. Of particular interest is the detection of voids and delaminations, encapsulated in the foam or at the interface between the foam and a metal backing. The technique is shown to be capable of imaging small voids and delaminations through as much as 20 cm of foam. Methods for reducing the temporal responses of the terahertz pulses to improve flaw detection and yield quantitative characterizations of the size and location of the flaws are discussed.

High-quality quantum-dot-based full-color display technology by pulsed spray method

NASA Astrophysics Data System (ADS)

Chen, Kuo-Ju; Chen, Hsin-Chu; Tsai, Kai-An; Lin, Chien-Chung; Tsai, Hsin-Han; Chien, Shih-Hsuan; Cheng, Bo-Siao; Hsu, Yung-Jung; Shih, Min-Hsiung; Kuo, Hao-Chung

2013-03-01

We fabricated the colloidal quantum-dot light-emitting diodes (QDLEDs) with the HfO2/SiO2-distributed Bragg reflector (DBR) structure using a pulsed spray coating method. Moreover, pixelated RGB arrays, 2-in. wafer-scale white light emission, and an integrated small footprint white light device were demonstrated. The experimental results showed that the intensity of red, blue, and green (RGB) emissions exhibited considerable enhancement because of the high reflectivity in the UV region by the DBR structure, which subsequently increased the use in the UV optical pumping of RGB QDs. In this experiment, a pulsed spray coating method was crucial in providing uniform RGB layers, and the polydimethylsiloxane (PDMS) film was used as the interface layer between each RGB color to avoid crosscontamination and self-assembly of QDs. Furthermore, the chromaticity coordinates of QDLEDs with the DBR structure remained constant under various pumping powers in the large area sample, whereas a larger shift toward high color temperatures was observed in the integrated device. The resulting color gamut of the proposed QDLEDs covered an area 1.2 times larger than that of the NTSC standard, which is favorable for the next generation of high-quality display technology.

Microstructural Analysis and Transport Properties of Thermally Sprayed Multiple-Layer Ceramic Coatings

DOE PAGES

Wang, Hsin; Muralidharan, Govindarajan; Leonard, Donovan N.; ...

2018-01-04

In this paper, multilayer, graded ceramic/metal coatings were prepared by an air plasma spray method on Ti-6Al-4V, 4140 steel and graphite substrates. The coatings were designed to provide thermal barriers for diesel engine pistons to operate at higher temperatures with improved thermal efficiency and cleaner emissions. A systematic, progressive variation in the mixture of yttria-stabilized zirconia and bondcoat alloys (NiCoCrAlYHfSi) was designed to provide better thermal expansion match with the substrate and to improve thermal shock resistance and cycle life. Heat transfer through the layers was evaluated by a flash diffusivity technique based on a model of one-dimensional heat flow.more » The aging effect of the as-sprayed coatings was captured during diffusivity measurements, which included one heating and cooling cycle. The hysteresis of thermal diffusivity due to aging was not observed after 100-h annealing at 800 °C. The measurements of coatings on substrate and freestanding coatings allowed the influence of interface resistance to be evaluated. Finally, the microstructure of the multilayer coating was examined using scanning electron microscope and electron probe microanalysis.« less

Fabrication and Wear Behavior of Nanostructured Plasma-Sprayed 6061Al-SiCp Composite Coating

NASA Astrophysics Data System (ADS)

Tailor, Satish; Mohanty, R. M.; Sharma, V. K.; Soni, P. R.

2014-10-01

6061Al powder with 15 wt.% SiC particulate (SiCp) reinforcement was mechanically alloyed (MA) in a high-energy attrition mill. The MA powder was then plasma sprayed onto weathering steel (Cor-Ten A242) substrate using an atmospheric plasma spray process. Results of particle size analysis and scanning electron microscopy show that the addition of SiC particles as the reinforcement influences on the matrix grain size and morphology. XRD studies revealed embedment of SiCp in the MA-processed composite powder, and nanocrystals in the MA powder and the coating. Microstructural studies showed a uniform distribution of reinforced SiC particles in the coating. The porosity level in the coating was as low as 2% while the coating hardness was increased to 232VHN. The adhesion strength of the coatings was high and this was attributed to higher degree of diffusion at the interface. The wear rate in the coatings was evaluated using a pin-on-disk type tribometer and found to decrease by 50% compared to the 6061Al matrix coating. The wear mechanism in the coating was delamination and oxidative type.

Microstructural Analysis and Transport Properties of Thermally Sprayed Multiple-Layer Ceramic Coatings

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

Wang, Hsin; Muralidharan, Govindarajan; Leonard, Donovan N.

In this paper, multilayer, graded ceramic/metal coatings were prepared by an air plasma spray method on Ti-6Al-4V, 4140 steel and graphite substrates. The coatings were designed to provide thermal barriers for diesel engine pistons to operate at higher temperatures with improved thermal efficiency and cleaner emissions. A systematic, progressive variation in the mixture of yttria-stabilized zirconia and bondcoat alloys (NiCoCrAlYHfSi) was designed to provide better thermal expansion match with the substrate and to improve thermal shock resistance and cycle life. Heat transfer through the layers was evaluated by a flash diffusivity technique based on a model of one-dimensional heat flow.more » The aging effect of the as-sprayed coatings was captured during diffusivity measurements, which included one heating and cooling cycle. The hysteresis of thermal diffusivity due to aging was not observed after 100-h annealing at 800 °C. The measurements of coatings on substrate and freestanding coatings allowed the influence of interface resistance to be evaluated. Finally, the microstructure of the multilayer coating was examined using scanning electron microscope and electron probe microanalysis.« less

Structure and Corrosion Behavior of Arc-Sprayed Zn-Al Coatings on Ductile Iron Substrate

NASA Astrophysics Data System (ADS)

Bonabi, Salar Fatoureh; Ashrafizadeh, Fakhreddin; Sanati, Alireza; Nahvi, Saied Mehran

2018-02-01

In this research, four coatings including pure zinc, pure aluminum, a double-layered coating of zinc and aluminum, and a coating produced by simultaneous deposition of zinc and aluminum were deposited on a cast iron substrate using electric arc-spraying technique. The coatings were characterized by XRD, SEM and EDS map and spot analyses. Adhesion strength of the coatings was evaluated by three-point bending tests, where double-layered coating indicated the lowest bending angle among the specimens, with detection of cracks at the coating-substrate interface. Coatings produced by simultaneous deposition of zinc and aluminum possessed a relatively uniform distribution of both metals. In order to evaluate the corrosion behavior of the coatings, cyclic polarization and salt spray tests were conducted. Accordingly, pure aluminum coating showed susceptibility to pitting corrosion and other coatings underwent uniform corrosion. For double-layered coating, SEM micrographs revealed zinc corrosion products as flaky particles in the pores formed by pitting on the surface, an indication of penetration of corrosion products from the lower layer (zinc) to the top layer (aluminum). All coatings experienced higher negative corrosion potentials than the iron substrate, indicative of their sacrificial behavior.

Device to improve detection in electro-chromatography

DOEpatents

Garguilo, Michael G.; Paul, Phillip H.; Rakestraw, David J.

2000-01-01

Apparatus and method for improving the resolution of non-pressure driven capillary chromatographic systems, and particularly for capillary electrochromatography (CEC) systems. By reducing the cross-sectional area of a packed capillary column by means of a second open capillary contiguous with the outlet end of a packed capillary column, where the packed capillary column has a cross sectional area of between about 2 and 5 times that of the open capillary column, the phenomenon of band broadening in the transition region between the open capillary and the packed capillary column, where the individual components of the mixture are analyzed, can be eliminated, thereby providing for a significant improvement in resolution and more accurate detection and analysis.

Device to improve detection in electro-chromatography

DOEpatents

Garguilo, Michael G.; Paul, Phillip H.; Rakestraw, David J.

2002-01-01

Apparatus and method for improving the resolution of non-pressure driven capillary chromatographic systems, and particularly for capillary electrochromatography (CEC) systems. By reducing the cross-sectional area of a packed capillary column by means of a second open capillary contiguous with the outlet end of a packed capillary column, where the packed capillary column has a cross sectional area of between about 2 and 5 times that of the open capillary column, the phenomenon of band broadening in the transition region between the open capillary and the packed capillary column, where the individual components of the mixture are analyzed, can be eliminated, thereby providing for a significant improvement in resolution and more accurate detection and analysis.

Liquid and gelled sprays for mixing hypergolic propellants using an impinging jet injection system

NASA Astrophysics Data System (ADS)

James, Mark D.

The characteristics of sprays produced by liquid rocket injectors are important in understanding rocket engine ignition and performance. The includes, but is not limited to, drop size distribution, spray density, drop velocity, oscillations in the spray, uniformity of mixing between propellants, and the spatial distribution of drops. Hypergolic ignition and the associated ignition delay times are also important features in rocket engines, providing high reliability and simplicity of the ignition event. The ignition delay time is closely related to the level and speed of mixing between a hypergolic fuel and oxidizer, which makes the injection method and conditions crucial in determining the ignition performance. Although mixing and ignition of liquid hypergolic propellants has been studied for many years, the processes for injection, mixing, and ignition of gelled hypergolic propellants are less understood. Gelled propellants are currently under investigation for use in rocket injectors to combine the advantages of solid and liquid propellants, although not without their own difficulties. A review of hypergolic ignition has been conducted for selected propellants, and methods for achieving ignition have been established. This research is focused on ignition using the liquid drop-on-drop method, as well as the doublet impinging jet injector. The events leading up to ignition, known as pre-ignition stage are discussed. An understanding of desirable ignition and combustion performance requires a study of the effects of injection, temperature, and ambient pressure conditions. A review of unlike-doublet impinging jet injection mixing has also been conducted. This includes mixing factors in reactive and non-reactive sprays. Important mixing factors include jet momentum, jet diameter and length, impingement angle, mass distribution, and injector configuration. An impinging jet injection system is presented using an electro-mechanically driven piston for injecting liquid and gelled hypergolic propellants. A calibration of the system is done with water in preparation for hypergolic injection, and characteristics of individual water and gelled JP-8 jets are studied at velocities in the range of 3 ft/s to 61 ft/s. The piston response is also analyzed to characterize the startup and steady state liquid jet velocities using orifices of 0.02" in diameter. Using this injection system, water and gelled JP-8 sprays are formed and compared across injection velocities of 30 ft/s to 121 ft/s. The comparison includes sheet shape and disintegration, total number of drops, drop size distributions, drop eccentricity, most populated drop bin size, and mean drop sizes. A test matrix for investigating the effects of mixing on ignition of MMH and IRFNA through different injection conditions are presented. First, water and IRFNA are injected to create a spray in the combustion chamber in order to verify effectiveness of test procedures and the test hardware. Next, injection of the hypergolic propellants MMH and IRFNA are done in accordance to the test matrix, although ignition was not observed as expected. These injections are followed by simple drop-on-drop tests to investigate propellant quality and ignition delay. Drop tests are performed with propellants IRFNA/MMH, and again with H2O2/Block 0 as possible propellant replacements for the proposed test plan.

Interface Magnetoelectric Coupling in Co/Pb(Zr,Ti)O3.

PubMed

Vlašín, Ondřej; Jarrier, Romain; Arras, Rémi; Calmels, Lionel; Warot-Fonrose, Bénédicte; Marcelot, Cécile; Jamet, Matthieu; Ohresser, Philippe; Scheurer, Fabrice; Hertel, Riccardo; Herranz, Gervasi; Cherifi-Hertel, Salia

2016-03-23

Magnetoelectric coupling at multiferroic interfaces is a promising route toward the nonvolatile electric-field control of magnetization. Here, we use optical measurements to study the static and dynamic variations of the interface magnetization induced by an electric field in Co/PbZr0.2Ti0.8O3 (Co/PZT) bilayers at room temperature. The measurements allow us to identify different coupling mechanisms. We further investigate the local electronic and magnetic structure of the interface by means of transmission electron microscopy, soft X-ray magnetic circular dichroism, and density functional theory to corroborate the coupling mechanism. The measurements demonstrate a mixed linear and quadratic optical response to the electric field, which results from a magneto-electro-optical effect. We propose a decomposition method of the optical signal to discriminate between different components involved in the electric field-induced polarization rotation of the reflected light. This allows us to extract a signal that we can ascribe to interface magnetoelectric coupling. The associated surface magnetization exhibits a clear hysteretic variation of odd symmetry with respect to the electric field and nonzero remanence. The interface coupling is remarkably stable over a wide frequency range (1-50 kHz), and the application of a bias magnetic field is not necessary for the coupling to occur. These results show the potential of exploiting interface coupling with the prospect of optimizing the performance of magnetoelectric memory devices in terms of stability, as well as fast and dissipationless operation.

Capillary Electrophoresis-nanoelectrospray Ionization-selected Reaction Monitoring Mass Spectrometry Via A True Sheathless Metal-coated Emitter Interface For Robust And High Sensitivity Sample Quantification

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

Guo, Xuejiang; Fillmore, Thomas L.; Gao, Yuqian

A new sheathless CITP/CZE-MS interface, based on a commercially available capillary with an integrated metal coated ESI emitter, was developed in this study aiming at overcoming the reproducibility and ruggedness problems, suffered to a certain degree by almost all the available CE-MS interfaces, and pushing the CE-MS technology suitable for routine sample analysis with high sensitivity. The new CITP/CZE-MS interface allows the electric contact between ESI voltage power supply and the CE separation liquid by using a conductive liquid that comes in contact with the metal coated surface of the ESI emitter, making it a true sheathless CE-MS interface. Stablemore » electrospray was established by avoiding the formation of gas bubbles from electro chemical reaction at the emitter tip or inside of the CE capillary. Crucial operating parameters, such as sample loading volume, flow rate, and separation voltage, were systematically evaluated for their effects on both CITP/CZE separation efficiency and MS detection sensitivity. Around one hundred CITP/CZE-MS analyses can be easily achieved by using the new sheathless CITP/CZE interface without a noticeable loss of metal coating on the ESI emitter surface, or degrading of the ESI emitter performance. The reproducibility in analyte migration time and quantitative performance of the new interface was experimentally evaluated to demonstrate a LOQ bellow 5 attomole.« less

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

Pradeepkumar, Aiswarya; Mishra, Neeraj; Kermany, Atieh Ranjbar

Epitaxial cubic silicon carbide on silicon is of high potential technological relevance for the integration of a wide range of applications and materials with silicon technologies, such as micro electro mechanical systems, wide-bandgap electronics, and graphene. The hetero-epitaxial system engenders mechanical stresses at least up to a GPa, pressures making it extremely challenging to maintain the integrity of the silicon carbide/silicon interface. In this work, we investigate the stability of said interface and we find that high temperature annealing leads to a loss of integrity. High–resolution transmission electron microscopy analysis shows a morphologically degraded SiC/Si interface, while mechanical stress measurementsmore » indicate considerable relaxation of the interfacial stress. From an electrical point of view, the diode behaviour of the initial p-Si/n-SiC junction is catastrophically lost due to considerable inter-diffusion of atoms and charges across the interface upon annealing. Temperature dependent transport measurements confirm a severe electrical shorting of the epitaxial silicon carbide to the underlying substrate, indicating vast predominance of the silicon carriers in lateral transport above 25 K. This finding has crucial consequences on the integration of epitaxial silicon carbide on silicon and its potential applications.« less

Elucidating the alkaline oxygen evolution reaction mechanism on platinum

DOE PAGES

Favaro, M.; Valero-Vidal, C.; Eichhorn, J.; ...

2017-03-07

Understanding the interplay between surface chemistry, electronic structure, and reaction mechanism of the catalyst at the electrified solid/liquid interface will enable the design of more efficient materials systems for sustainable energy production. The substantial progress in operando characterization, particularly using synchrotron based X-ray spectroscopies, provides the unprecedented opportunity to uncover surface chemical and structural transformations under various (electro)chemical reaction environments. In this work, we study a polycrystalline platinum surface under oxygen evolution conditions in an alkaline electrolyte by means of ambient pressure X-ray photoelectron spectroscopy performed at the electrified solid/liquid interface. We elucidate previously inaccessible aspects of the surface chemistrymore » and structure as a function of the applied potential, allowing us to propose a reaction mechanism for oxygen evolution on a platinum electrode in alkaline solutions.« less

Ion Chromatography-on-a-chip for Water Quality Analysis

NASA Technical Reports Server (NTRS)

Kidd, R. D.; Noell, A.; Kazarians, G.; Aubrey, A. D.; Scianmarello, N.; Tai, Y.-C.

2015-01-01

We report progress towards developing a Micro-Electro-Mechanical Systems (MEMS)- based ion chromatograph (IC) for crewed spacecraft water analysis. This IC-chip is an offshoot of a NASA-funded effort to produce a high performance liquid chromatograph (HPLC)-chip. This HPLC-chip system would require a desalting (i.e. ion chromatography) step. The complete HPLC instrument consists of the Jet Propulsion Labortory's (JPL's) quadrupole ion trap mass spectrometer integrated with a state-of-the-art MEMS liquid chromatograph (LC) system developed by the California Institute of Technology's (Caltech's) Micromachining Laboratory. The IC version of the chip consist of an electrolysis-based injector, a separation column, two electrolysis pumps for gradient generation, mixer, and a built-in conductivity detector. The HPLC version of the chip also includes a nanospray tip. The low instrument mass, coupled with its high analytical capabilities, makes the LC chip ideally suitable for wide range of applications such as trace contaminant, inorganic analytical science and, when coupled to a mass spectrometer, a macromolecular detection system for either crewed space exploration vehicles or robotic planetary missions.

Rotational fluid flow experiment: WPI/MITRE advanced space design GASCAN 2

NASA Technical Reports Server (NTRS)

Daly, Walter F.; Harr, Lee; Paduano, Rocco; Yee, Tony; Eubbani, Eddy; Delprado, Jaime; Khanna, Ajay

1991-01-01

The design and implementation is examined of an electro-mechanical system for studying vortex behavior in a microgravity environment. Most of the existing equipment was revised and redesigned as necessary. Emphasis was placed on the documentation and integration of the mechanical and electrical subsystems. Project results include the reconfiguration and thorough testing of all the hardware subsystems, the implementation of an infrared gas entrainment detector, new signal processing circuitry for the ultrasonic fluid circulation device, improved prototype interface circuits, and software for overall control of experiment design operation.

Electro-chemical manifestation of nanoplasmonics in fractal media

NASA Astrophysics Data System (ADS)

Baskin, Emmanuel; Iomin, Alexander

2013-06-01

Electrodynamics of composite materials with fractal geometry is studied in the framework of fractional calculus. This consideration establishes a link between fractal geometry of the media and fractional integrodifferentiation. The photoconductivity in the vicinity of the electrode-electrolyte fractal interface is studied. The methods of fractional calculus are employed to obtain an analytical expression for the giant local enhancement of the optical electric field inside the fractal composite structure at the condition of the surface plasmon excitation. This approach makes it possible to explain experimental data on photoconductivity in the nano-electrochemistry.

Coating Development for GRCop-84 Liners for Reusable Launch Vehicles Aided by Modeling Studies

NASA Technical Reports Server (NTRS)

Raj, Sai V.; Ghosn, Louis J.

2004-01-01

The design of the next generation of reusable launch vehicles calls for using GRCop-84 copper alloy liners based on a composition invented at the NASA Glenn Research Center. Despite its considerable advantage over other copper alloys, it is expected that GRCop-84 will suffer from environmental degradation depending on the type of rocket fuels used and on thermomechanical fatigue. Applying protective coatings on GRCop-84 substrates can minimize or eliminate many of these problems and extend the operational life of the combustion liner. This could increase component reliability, shorten depot maintenance turnaround times, and lower operating costs. Therefore, Glenn is actively pursuing the development of advanced coatings technology for GRCop-84 liners. Technology is being developed in four major areas: (1) new metallic coating compositions, (2) application techniques, (3) test methods, and (4) life prediction design methodology using finite element analysis. The role of finite element analysis in guiding the coating effort is discussed in this report. Thermal analyses were performed at Glenn for different combinations of top- and bondcoat compositions to determine the temperature variation across the coated cross section with the thickness of the top coat. These calculations were conducted for simulated LH2/LO2 booster engine conditions assuming that the bond coat had a constant thickness of 50 m. The preceding graphs show the predicted temperatures at the outer surface of the top coat (hot wall), at the top-coat/bond-coat interface, at the bond-coat/GRCop-84 interface, and at the GRCop-84 cold wall as a function of top-coat thickness for Cu- 26(wt%)Cr top coat (top graph), Ni-17(wt%)Cr-6%Al-0.5%Y top coat and Cu-26%Cr bond coat, and NiAl top coat and Ni bond coat. In all cases, the temperature of the top coat at the hot wall increased with increasing top-coat thickness and with corresponding decreases in the temperatures at the two interfaces and the cold wall. These temperatures are not acutely sensitive to the thermal conductivity of the top coat when it exceeds 25 and 50 W/m/K for low and high heat flux engines. This observation is significant for two reasons. First, several different top-coat compositions can be evaluated as potential protective coatings without loss in the heat-transfer efficiency of the coated system. Second, materials with thermal conductivities less than the critical values of 25 or 50 W/m/K are more likely to act as thermal barrier coatings. The deposition of overlay coatings on GRCop-84 substrates results in the development of residual stresses. The presence of these residual stresses influences the probability of coating spallation, the thermal cycling life, and the fatigue properties of the coated substrate during use. Since it is important to understand how these stresses develop during the vacuum-plasma-spraying coating deposition process, the nature and magnitudes of the cool-down residual stresses were calculated and compared with experimentally determined values across the coated cross section of a disk specimen. The calculations were conducted assuming that the specimen cools down to room temperature from vacuum plasma-spraying temperatures of either 250 or 650 C. The effects of coating the substrate with and without grit blasting were also theoretically examined. The final graph compares the predicted and the experimental results for a GRCop-84 disk coated with about a 50- m-thick Ni bond coat and a 75- to 100- m NiAl top coat, where the curves for NASA-2 assume the presence of a prior residual stress generated by grit blasting under conditions similar to the experimental situation. The predicted cool-down in-plane stresses were compressive in both the NiAl top coat and the Ni bond coat. They were also compressive in the substrate to a depth of about 0.25 mm from the Ni/GRCop-84 interface when the vacuum-plasma-spraying temperature was low. However, using a higher plasma spraying temperaturs likely to leave the substrate under a small tensile stress to counter the compressive stresses in the bond and top coats because of the relaxation of residual stresses generated in the substrate during the grit blasting of its surface prior to spraying. These results suggest that the NiAl and Ni coatings are unlikely to spall after spraying as confirmed by the microstructural observations shown in the following photomicrograph of an as-sprayed specimen. Finally, it is noted that the calculated and experimental results are not in complete agreement, which indicates that both the experimental and modeling techniques need further refinement.

Bond strength determination of hydroxyapatite coatings on Ti-6Al-4V substrates using the LAser Shock Adhesion Test (LASAT).

PubMed

Guipont, Vincent; Jeandin, Michel; Bansard, Sebastien; Khor, Khiam Aik; Nivard, Mariette; Berthe, Laurent; Cuq-Lelandais, Jean-Paul; Boustie, Michel

2010-12-15

An adhesion test procedure applied to plasma-sprayed hydroxyapatite (HA) coatings to measure the "LASAT threshold" (LAser Shock Adhesion test) is described. The good repeatability and minimal discrepancy of the laser-driven adhesion test data were ascertained for conventional plasma sprayed HA coatings. As a further demonstration, the procedure was applied to HA coatings with diverse characteristics on the ceramic/metal interface. Different preheating and grit blasting conditions and the presence of a thick plasma-sprayed Ti sublayer or a thin TiO(2) layer prepared by oxidation were investigated through LASAT. It was assessed that a rough surface can significantly improve the coating's bond strength. However, it was also demonstrated that a thin TiO(2) layer on a smooth Ti-6Al-4V substrate can have a major influence on adhesion as well. Preheating up to 270°C just prior to the first HA spraying pass had no effect on the adhesion strength. Further development of the procedure was done to achieve an in situ LASAT with in vitro conditions applied on HA coatings. To that end, different crystalline HA contents were soaked in simulated body fluid (SBF). Beyond the demonstration of the capability of this laser-driven adhesion test devoted to HA coatings in dry or liquid environment, the present study provided empirical information on pertinent processing characteristics that could strengthen or weaken the HA/Ti-6Al-4V bond. Copyright © 2010 Wiley Periodicals, Inc.

Structure of a bimetallic strip produced by plasma spraying of a TiAl powder on a niobium sheet

NASA Astrophysics Data System (ADS)

Povarova, K. B.; Antonova, A. V.; Burmistrov, V. I.; Safronov, B. V.; Perfilov, L. S.; Chukanov, A. P.

2007-10-01

Ti-48 at % Al alloy granules produced by centrifugal spraying are milled into a powder with a particle size of 40 100 μm, and are applied onto a niobium foil using plasma spraying in an argon atmosphere. The fabricated TiAl/Nb bimetallic strip consists of a 100-μm-thick niobium layer and a porous 300-to 400-μm-thick TiAl layer formed by flattened particles. Directly after the preparation of the bimetallic strip, the surface of the TiAl porous layer is rough. Vacuum annealing at 1000, 1100, and 1200°C for 0.5 1.5 h leads to intense pore healing. After deposition and annealing, the interlayer adhesion is strong. The preparation of TiAl granules and spraying of the powder is accompanied by aluminum depletion of the Ti-48 at % Al alloy to 42 45 at % and an increase in the fraction of the α2-Ti3Al phase in the deposited layer. The prepared material has a duplex structure. An intermediate diffuse layer characterized by a variable composition and thickness is formed at the interface. This layer consists of two solid solutions; one of them, which is formed at the TiAl layer, is an α2-Ti3Al-based solid solution of niobium and the other, which is formed at the niobium foil, is a niobium-based solid solution of titanium and aluminum.

Electrospray Collection of Lunar Dust

NASA Technical Reports Server (NTRS)

Dziekan, Michael

2012-01-01

A report describes ElectroSpray Ionization based Electrostatic Precipitation (ESIEP) for collecting lunar dust particles. While some HEPA filtration processes may remove a higher fraction (>99.9 percent) of the particles, the high efficiency may not be appropriate from an overall system standpoint, especially in light of the relatively large power requirement that such systems demand. The new electrospray particle capture technology is described as a variant of electrostatic precipitation that eliminates the current drawbacks of electrostatic precipitation. The new approach replaces corona prone field with a mist of highly charged micro-droplets generated by electrospray ionization (ESI) as the mechanism by which incoming particles are attracted and captured. In electrospray, a miniscule flow rate (microliters/minute) of liquid (typically water and a small amount of salt to enhance conductivity) is fed from the tip of a needle held at a high voltage potential relative to an opposite counter electrode. At sufficient field strength, a sharp liquid meniscus forms , which emits a jet of highly charged droplets that drift through the surrounding gas and are collected on the walls of a conductive tube. Particles in the gas have a high probability of contact with the droplets either by adhering to the droplets or otherwise acquiring a high level of charge, causing them to be captured on the collecting electrode as well. The spray acts as a filtration material that is continuously introduced and removed from the gas flow, and thus can never become clogged.

Modeling and Design of an Electro-Rheological Fluid Based Haptic System for Tele-Operation of Space Robots

NASA Technical Reports Server (NTRS)

Mavroidis, Constantinos; Pfeiffer, Charles; Paljic, Alex; Celestino, James; Lennon, Jamie; Bar-Cohen, Yoseph

2000-01-01

For many years, the robotic community sought to develop robots that can eventually operate autonomously and eliminate the need for human operators. However, there is an increasing realization that there are some tasks that human can perform significantly better but, due to associated hazards, distance, physical limitations and other causes, only robot can be employed to perform these tasks. Remotely performing these types of tasks requires operating robots as human surrogates. While current "hand master" haptic systems are able to reproduce the feeling of rigid objects, they present great difficulties in emulating the feeling of remote/virtual stiffness. In addition, they tend to be heavy, cumbersome and usually they only allow limited operator workspace. In this paper a novel haptic interface is presented to enable human-operators to "feel" and intuitively mirror the stiffness/forces at remote/virtual sites enabling control of robots as human-surrogates. This haptic interface is intended to provide human operators intuitive feeling of the stiffness and forces at remote or virtual sites in support of space robots performing dexterous manipulation tasks (such as operating a wrench or a drill). Remote applications are referred to the control of actual robots whereas virtual applications are referred to simulated operations. The developed haptic interface will be applicable to IVA operated robotic EVA tasks to enhance human performance, extend crew capability and assure crew safety. The electrically controlled stiffness is obtained using constrained ElectroRheological Fluids (ERF), which changes its viscosity under electrical stimulation. Forces applied at the robot end-effector due to a compliant environment will be reflected to the user using this ERF device where a change in the system viscosity will occur proportionally to the force to be transmitted. In this paper, we will present the results of our modeling, simulation, and initial testing of such an electrorheological fluid (ERF) based haptic device.

Bioanalytical Applications of Fluorescence Line-Narrowing and Non-Line-Narrowing Spectroscopy Interfaced with Capillary Electrophoresis and High-Performance Liquid Chromatography

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

Roberts, Kenneth Paul

Capillary electrophoresis (CE) and high-performance liquid chromatography (HPLC) are widely used analytical separation techniques with many applications in chemical, biochemical, and biomedical sciences. Conventional analyte identification in these techniques is based on retention/migration times of standards; requiring a high degree of reproducibility, availability of reliable standards, and absence of coelution. From this, several new information-rich detection methods (also known as hyphenated techniques) are being explored that would be capable of providing unambiguous on-line identification of separating analytes in CE and HPLC. As further discussed, a number of such on-line detection methods have shown considerable success, including Raman, nuclear magnetic resonancemore » (NMR), mass spectrometry (MS), and fluorescence line-narrowing spectroscopy (FLNS). In this thesis, the feasibility and potential of combining the highly sensitive and selective laser-based detection method of FLNS with analytical separation techniques are discussed and presented. A summary of previously demonstrated FLNS detection interfaced with chromatography and electrophoresis is given, and recent results from on-line FLNS detection in CE (CE-FLNS), and the new combination of HPLC-FLNS, are shown.« less

High mobility organic field-effect transistor based on water-soluble deoxyribonucleic acid via spray coating

NASA Astrophysics Data System (ADS)

Shi, Wei; Han, Shijiao; Huang, Wei; Yu, Junsheng

2015-01-01

High mobility organic field-effect transistors (OFETs) by inserting water-soluble deoxyribonucleic acid (DNA) buffer layer between electrodes and pentacene film through spray coating process were fabricated. Compared with the OFETs incorporated with DNA in the conventional organic solvents of ethanol and methanol: water mixture, the water-soluble DNA based OFET exhibited an over four folds enhancement of field-effect mobility from 0.035 to 0.153 cm2/Vs. By characterizing the surface morphology and the crystalline structure of pentacene active layer through atomic force microscope and X-ray diffraction, it was found that the adoption of water solvent in DNA solution, which played a key role in enhancing the field-effect mobility, was ascribed to both the elimination of the irreversible organic solvent-induced bulk-like phase transition of pentacene film and the diminution of a majority of charge trapping at interfaces in OFETs.

Strain isolated ceramic coatings

NASA Technical Reports Server (NTRS)

Tolokan, R. P.; Brady, J. B.; Jarrabet, G. P.

1985-01-01

Plasma sprayed ceramic coatings are used in gas turbine engines to improve component temperature capability and cooling air efficiency. A compliant metal fiber strain isolator between a plasma sprayed ceramic coating and a metal substrate improves ceramic durability while allowing thicker coatings for better insulation. Development of strain isolated coatings has concentrated on design and fabrication of coatings and coating evaluation via thermal shock testing. In thermal shock testing, five types of failure are possible: buckling failure im compression on heat up, bimetal type failure, isothermal expansion mismatch failure, mudflat cracking during cool down, and long term fatigue. A primary failure mode for thermally cycled coatings is designated bimetal type failure. Bimetal failure is tensile failure in the ceramic near the ceramic-metal interface. One of the significant benefits of the strain isolator is an insulating layer protecting the metal substrate from heat deformation and thereby preventing bimetal type failure.

Non-monotonous dependence of the ocean surface drag coefficient on the hurricane wind speed due to the fragmentation of the ocean-atmosphere interface

NASA Astrophysics Data System (ADS)

Troitskaya, Yu. I.; Ermakova, O. S.; Kandaurov, A. A.; Kozlov, D. S.; Sergeev, D. A.; Zilitinkevich, S. S.

2017-11-01

Influence of the spray generation due to the fragmentation of the "bag-breakup" type on momentum exchange in the atmospheric boundary layer above the sea surface at hurricane winds was investigated on the basis of the analysis of the results of laboratory experiments. It was shown that aerodynamic drag is determined by the contribution of three factors: first, the drag of the "bag-breakup" canopies as obstacles; second, acceleration of the spray formed during fragmentation by the air flow; and the third factor is related to the stratification of the near-water atmospheric layer due to the presence of levitated water droplets. Combination of all three factors leads to a non-monotonous dependence of the aerodynamic drag coefficient on wind speed, which confirms the results of the field and laboratory measurements.

Degradation of insecticides used for indoor spraying in malaria control and possible solutions

PubMed Central

2011-01-01

Background The insecticide dichloro-diphenyl-trichloroethane (DDT) is widely used in indoor residual spraying (IRS) for malaria control owing to its longer residual efficacy in the field compared to other World Health Organization (WHO) alternatives. Suitable stabilization to render these alternative insecticides longer lasting could provide a less controversial and more acceptable and effective alternative insecticide formulations than DDT. Methods This study sought to investigate the reasons behind the often reported longer lasting behaviour of DDT by exposing all the WHO approved insecticides to high temperature, high humidity and ultra-violet light. Interactions between the insecticides and some mineral powders in the presence of an aqueous medium were also tested. Simple insecticidal paints were made using slurries of these mineral powders whilst some insecticides were dispersed into a conventional acrylic paint binder. These formulations were then spray painted on neat and manure coated mud plaques, representative of the material typically used in rural mud houses, at twice the upper limit of the WHO recommended dosage range. DDT was applied directly onto mud plaques at four times the WHO recommended concentration and on manure plaques at twice WHO recommended concentration. All plaques were subjected to accelerated ageing conditions of 40°C and a relative humidity of 90%. Results The pyrethroids insecticides outperformed the carbamates and DDT in the accelerated ageing tests. Thus UV exposure, high temperature oxidation and high humidity per se were ruled out as the main causes of failure of the alternative insecticides. Gas chromatography (GC) spectrograms showed that phosphogypsum stabilised the insecticides the most against alkaline degradation (i.e., hydrolysis). Bioassay testing showed that the period of efficacy of some of these formulations was comparable to that of DDT when sprayed on mud surfaces or cattle manure coated surfaces. Conclusions Bioassay experiments indicated that incorporating insecticides into a conventional paint binder or adsorbing them onto phosphogypsum can provide for extended effective life spans that compare favourably with DDT's performance under accelerated ageing conditions. Best results were obtained with propoxur in standard acrylic emulsion paint. Similarly, insecticides adsorbed on phosphogypsum and sprayed on cattle manure coated surfaces provided superior lifespans compared with DDT sprayed directly on a similar surface. PMID:22008292

Antibiotic residues in milk samples obtained from cows after treatment for papillomatous digital dermatitis.

PubMed

Britt, J S; Carson, M C; von Bredow, J D; Condon, R J

1999-09-15

To determine whether there would be detectable antibiotic residues in milk obtained from dairy cattle with papillomatous digital dermatitis (PDD) after topical treatment with oxytetracycline. Randomized controlled clinical trial. 28 lactating Holstein cows with PDD. Cows were assigned to 2 treatment groups. Treatment 1 (n = 16) consisted of spraying of PDD lesions with 15 ml of a solution containing 100 mg of oxytetracycline/ml; lesions were sprayed twice daily for 7 days, using a garden sprayer. Treatment 2 (n = 12) consisted of a one-time application of a bandage that consisted of cotton soaked with 20 ml of a solution containing 100 mg of oxytetracycline/ml. Milk samples were obtained before and after treatment and assayed for tetracycline content by use of high-performance liquid chromatography and a commercially available tetracycline screening test. None of the cows in either treatment group had violative residues of oxytetracycline in milk samples. Producers treating lactating cows that have PDD, via topical application of oxytetracycline solution at the concentrations reported in this study, have a low risk of causing violative antibiotic residues in milk.

Paclitaxel-loaded poly(lactide-co-glycolide)/poly(ethylene vinyl acetate) composite for stent coating by ultrasonic atomizing spray.

PubMed

Yuk, Soon Hong; Oh, Keun Sang; Park, Jinah; Kim, Soon-Joong; Kim, Jung Ho; Kwon, Il Keun

2012-04-01

The mixture of poly(lactide-co-glycolide) (PLGA) and poly(ethylene vinyl acetate) (PEVA) forms a homogeneous liquid in an organic solvent such as tetrahydrofuran, and a phase-separated PLGA/PEVA composite can be prepared from it by evaporating the organic solvent. Exploiting this phenomenon, we designed a novel method of preparing a drug-loaded PLGA/PEVA composite and used it for coating drug-eluting stents (DESs). Paclitaxel (PTX), an anticancer drug, was chosen as a model drug. PLGA acts as a microdepot for PTX, and PEVA provides mechanical strength to the coating material. The presence of PLGA in the PLGA/PEVA composite suppressed PTX crystallization in the coating material, and PTX showed a sustained release rate over more than 30 days. The mechanical strength of the PLGA/PEVA composite was better than that of PEVA used as a control. After coating the stent with a PLGA/PEVA composite using ultrasonic atomizing spray, the morphology of the coated material was observed by scanning electron microscopy, and the release pattern of PTX was measured by high-performance liquid chromatography.

Paclitaxel-loaded poly(lactide-co-glycolide)/poly(ethylene vinyl acetate) composite for stent coating by ultrasonic atomizing spray

PubMed Central

Yuk, Soon Hong; Oh, Keun Sang; Park, Jinah; Kim, Soon-Joong; Kim, Jung Ho; Kwon, Il Keun

2012-01-01

The mixture of poly(lactide-co-glycolide) (PLGA) and poly(ethylene vinyl acetate) (PEVA) forms a homogeneous liquid in an organic solvent such as tetrahydrofuran, and a phase-separated PLGA/PEVA composite can be prepared from it by evaporating the organic solvent. Exploiting this phenomenon, we designed a novel method of preparing a drug-loaded PLGA/PEVA composite and used it for coating drug-eluting stents (DESs). Paclitaxel (PTX), an anticancer drug, was chosen as a model drug. PLGA acts as a microdepot for PTX, and PEVA provides mechanical strength to the coating material. The presence of PLGA in the PLGA/PEVA composite suppressed PTX crystallization in the coating material, and PTX showed a sustained release rate over more than 30 days. The mechanical strength of the PLGA/PEVA composite was better than that of PEVA used as a control. After coating the stent with a PLGA/PEVA composite using ultrasonic atomizing spray, the morphology of the coated material was observed by scanning electron microscopy, and the release pattern of PTX was measured by high-performance liquid chromatography. PMID:27877483

Paclitaxel-loaded poly(lactide-co-glycolide)/poly(ethylene vinyl acetate) composite for stent coating by ultrasonic atomizing spray

NASA Astrophysics Data System (ADS)

Yuk, Soon Hong; Oh, Keun Sang; Park, Jinah; Kim, Soon-Joong; Kim, Jung Ho; Kwon, Il Keun

2012-04-01

The mixture of poly(lactide-co-glycolide) (PLGA) and poly(ethylene vinyl acetate) (PEVA) forms a homogeneous liquid in an organic solvent such as tetrahydrofuran, and a phase-separated PLGA/PEVA composite can be prepared from it by evaporating the organic solvent. Exploiting this phenomenon, we designed a novel method of preparing a drug-loaded PLGA/PEVA composite and used it for coating drug-eluting stents (DESs). Paclitaxel (PTX), an anticancer drug, was chosen as a model drug. PLGA acts as a microdepot for PTX, and PEVA provides mechanical strength to the coating material. The presence of PLGA in the PLGA/PEVA composite suppressed PTX crystallization in the coating material, and PTX showed a sustained release rate over more than 30 days. The mechanical strength of the PLGA/PEVA composite was better than that of PEVA used as a control. After coating the stent with a PLGA/PEVA composite using ultrasonic atomizing spray, the morphology of the coated material was observed by scanning electron microscopy, and the release pattern of PTX was measured by high-performance liquid chromatography.

Science Notes.

ERIC Educational Resources Information Center

Murray, A. J. S.; And Others

1988-01-01

Presents 31 science activities for use with high school or college science classes. Topics included are: chromatography, ecology, invertebrates, enzymes, genetics, botany, creep, crystals, diffusion, computer interfaces, acid rain, teaching techniques, chemical reactions, waves, electric fields, rainbows, electricity, magnetic fields, and a Pitot…

Hydrophilic Interaction Liquid Chromatography-Tandem Mass Spectrometry Analysis of Fosetyl-Aluminum in Airborne Particulate Matter

PubMed Central

Di Filippo, Patrizia; Riccardi, Carmela; Pomata, Donatella; Marsiglia, Riccardo; Console, Carla; Puri, Daniele

2018-01-01

Fosetyl-aluminum is a synthetic fungicide administered to plants especially to prevent diseases caused by the members of the Peronosporales and several Phytophthora species. Herein, we present a selective liquid chromatography-tandem mass spectrometry (LC-MS/MS) method to analyze residues of fosetyl-A1 in air particulate matter. This study was performed in perspective of an exposure assessment of this substance of health concern in environments where high levels of fosetly-Al, relatively to airborne particulate matter, can be found after spraying it. The cleanup procedure of the analyte, from sampled filters of atmospheric particulate matter, was optimized using a Strata X solid-phase extraction cartridge, after accelerated extraction by using water. The chromatographic separation was achieved using a polymeric column based on hydrophilic interaction in step elution with water/acetonitrile, whereas the mass spectrometric detection was performed in negative electrospray ionization. The proposed method resulted to be a simple, fast, and suitable method for confirmation purposes. PMID:29686933

The Effectiveness of Surface Coatings on Preventing Interfacial Reaction During Ultrasonic Welding of Aluminum to Magnesium

NASA Astrophysics Data System (ADS)

Panteli, Alexandria; Robson, Joseph D.; Chen, Ying-Chun; Prangnell, Philip B.

2013-12-01

High power ultrasonic spot welding (USW) is a solid-state joining process that is advantageous for welding difficult dissimilar material couples, like magnesium to aluminum. USW is also a useful technique for testing methods of controlling interfacial reaction in welding as the interface is not greatly displaced by the process. However, the high strain rate deformation in USW has been found to accelerate intermetallic compound (IMC) formation and a thick Al12Mg17 and Al3Mg2 reaction layer forms after relatively short welding times. In this work, we have investigated the potential of two approaches for reducing the IMC reaction rate in dissimilar Al-Mg ultrasonic welds, both involving coatings on the Mg sheet surface to (i) separate the join line from the weld interface, using a 100- μm-thick Al cold spray coating, and (ii) provide a diffusion barrier layer, using a thin manganese physical vapor deposition (PVD) coating. Both methods were found to reduce the level of reaction and increase the failure energy of the welds, but their effectiveness was limited due to issues with coating attachment and survivability during the welding cycle. The effect of the coatings on the joint's interface microstructure, and the fracture behavior have been investigated in detail. Kinetic modeling has been used to show that the benefit of the cold spray coating can be attributed to the reaction rate reverting to that expected under static conditions. This reduces the IMC growth rate by over 50 pct because at the weld line, the high strain rate dynamic deformation in USW normally enhances diffusion through the IMC layer. In comparison, the thin PVD barrier coating was found to rapidly break up early in USW and become dispersed throughout the deformation layer reducing its effectiveness.

Online Simultaneous Hydrogen/Deuterium Exchange of Multitarget Gas-Phase Molecules by Electrospray Ionization Mass Spectrometry Coupled with Gas Chromatography.

PubMed

Jeong, Eun Sook; Cha, Eunju; Cha, Sangwon; Kim, Sunghwan; Oh, Han Bin; Kwon, Oh-Seung; Lee, Jaeick

2017-11-21

In this study, a hydrogen/deuterium (H/D) exchange method using gas chromatography-electrospray ionization/mass spectrometry (GC-ESI/MS) was first investigated as a novel tool for online H/D exchange of multitarget analytes. The GC and ESI source were combined with a homemade heated column transfer line. GC-ESI/MS-based H/D exchange occurs in an atmospheric pressure ion source as a result of reacting the gas-phase analyte eluted from GC with charged droplets of deuterium oxide infused as the ESI spray solvent. The consumption of the deuterated solvent at a flow rate of 2 μL min -1 was more economical than that in online H/D exchange methods reported to date. In-ESI-source H/D exchange by GC-ESI/MS was applied to 11 stimulants with secondary amino or hydroxyl groups. After H/D exchange, the spectra of the stimulants showed unexchanged, partially exchanged, and fully exchanged ions showing various degrees of exchange. The relative abundances corrected for naturally occurring isotopes of the fully exchanged ions of stimulants, except for etamivan, were in the range 24.3-85.5%. Methylephedrine and cyclazodone showed low H/D exchange efficiency under acidic, neutral, and basic spray solvent conditions and nonexchange for etamivan with an acidic phenolic OH group. The in-ESI-source H/D exchange efficiency by GC-ESI/MS was sufficient to determine the number of hydrogen by elucidation of fragmentation from the spectrum. Therefore, this online H/D exchange technique using GC-ESI/MS has potential as an alternative method for simultaneous H/D exchange of multitarget analytes.

An ionic electro-active actuator made with graphene film electrode, chitosan and ionic liquid

NASA Astrophysics Data System (ADS)

He, Qingsong; Yu, Min; Yang, Xu; Kim, Kwang Jin; Dai, Zhendong

2015-06-01

A newly developed ionic electro-active actuator composed of an ionic electrolyte layer sandwiched between two graphene film layers was investigated. Scanning electronic microscopy observation and x-ray diffraction analysis showed that the graphene sheets in the film stacked in a nearly face-to-face fashion but did not restack back to graphite, and the resulting graphene film with low sheet resistance (10 Ω sq-1) adheres well to the electrolyte membrane. Contact angle measurement showed the surface energy (37.98 mJ m-2) of the ionic electrolyte polymer is 2.67 times higher than that (14.2 mJ m-2) of the Nafion membrane, contributing to the good adhesion between the graphene film electrode and the electrolyte membrane. An electric double-layer is formed at the interface between the graphene film electrode and the ionic electrolyte membrane under the input potential, resulting in a higher capacitance of 27.6 mF cm-2. We report that this ionic actuator exhibits adequate bending strain, ranging from 0.032 to 0.1% (305 to 945 μm) as functions of voltage.

Changes of composition and microstructure of joint interface of tungsten coated carbon by high heat flux

NASA Astrophysics Data System (ADS)

Tokunaga, K.; Matsubara, T.; Miyamoto, Y.; Takao, Y.; Yoshida, N.; Noda, N.; Kubota, Y.; Sogabe, T.; Kato, T.; Plöchl, L.

2000-12-01

Tungsten coatings of 0.5 and 1 mm thickness were successfully deposited by the vacuum plasma spraying (VPS) technique on carbon/carbon fiber composite (CFC), CX-2002U and isotropic fine grained graphite, IG-430U. High heat flux experiments by irradiation of electron beam with uniform profile were performed on the coated samples in order to prove the suitability and load limit of such coating materials. The cross-sectional composition and structure of the interface of VPS-W and carbon material samples were investigated. Compositional analyses showed that the Re/W multi-layer acts as diffusion barrier for carbon and suppresses tungsten carbide formation in the VPS-W layer at high temperature about 1300°C. Microstructure of the joint interface of the sample changed in the case of a peak temperature of about 2800°C. The multi-layer structure completely disappeared and compositional distribution was almost uniform in the interface of the sample after melting and resolidification. The diffusion barrier for carbon is not expected to act in this stage.

Quantitation of zolpidem in biological fluids by electro-driven microextraction combined with HPLC-UV analysis.

PubMed

Yaripour, Saeid; Mohammadi, Ali; Esfanjani, Isa; Walker, Roderick B; Nojavan, Saeed

2018-01-01

In this study, for the first time, an electro-driven microextraction method named electromembrane extraction combined with a simple high performance liquid chromatography and ultraviolet detection was developed and validated for the quantitation of zolpidem in biological samples. Parameters influencing electromembrane extraction were evaluated and optimized. The membrane consisted of 2-ethylhexanol immobilized in the pores of a hollow fiber. As a driving force, a 150 V electric field was applied to facilitate the analyte migration from the sample matrix to an acceptor solution through a supported liquid membrane. The pHs of donor and acceptor solutions were optimized to 6.0 and 2.0, respectively. The enrichment factor was obtained >75 within 15 minutes. The effect of carbon nanotubes (as solid nano-sorbents) on the membrane performance and EME efficiency was evaluated. The method was linear over the range of 10-1000 ng/mL for zolpidem (R 2 >0.9991) with repeatability ( %RSD) between 0.3 % and 7.3 % ( n = 3). The limits of detection and quantitation were 3 and 10 ng/mL, respectively. The sensitivity of HPLC-UV for the determination of zolpidem was enhanced by electromembrane extraction. Finally, the method was employed for the quantitation of zolpidem in biological samples with relative recoveries in the range of 60-79 %.

Quantitation of zolpidem in biological fluids by electro-driven microextraction combined with HPLC-UV analysis

PubMed Central

Yaripour, Saeid; Mohammadi, Ali; Esfanjani, Isa; Walker, Roderick B.; Nojavan, Saeed

2018-01-01

In this study, for the first time, an electro-driven microextraction method named electromembrane extraction combined with a simple high performance liquid chromatography and ultraviolet detection was developed and validated for the quantitation of zolpidem in biological samples. Parameters influencing electromembrane extraction were evaluated and optimized. The membrane consisted of 2-ethylhexanol immobilized in the pores of a hollow fiber. As a driving force, a 150 V electric field was applied to facilitate the analyte migration from the sample matrix to an acceptor solution through a supported liquid membrane. The pHs of donor and acceptor solutions were optimized to 6.0 and 2.0, respectively. The enrichment factor was obtained >75 within 15 minutes. The effect of carbon nanotubes (as solid nano-sorbents) on the membrane performance and EME efficiency was evaluated. The method was linear over the range of 10-1000 ng/mL for zolpidem (R2 >0.9991) with repeatability ( %RSD) between 0.3 % and 7.3 % (n = 3). The limits of detection and quantitation were 3 and 10 ng/mL, respectively. The sensitivity of HPLC-UV for the determination of zolpidem was enhanced by electromembrane extraction. Finally, the method was employed for the quantitation of zolpidem in biological samples with relative recoveries in the range of 60-79 %. PMID:29805344

Extraction of antioxidants from olive mill wastewater and electro-coagulation of exhausted fraction to reduce its toxicity on anaerobic digestion.

PubMed

Khoufi, Sonia; Aloui, Fathi; Sayadi, Sami

2008-03-01

Liquid-liquid extraction was used in order to recover phenolic compounds from centrifuged olive mill wastewater (OMW), a polluting by-product of olive oil production process, and to reduce their toxicity for a subsequent aerobic or anaerobic digestion. Phenolic compounds were identified in untreated and treated OMW by gas chromatography coupled to mass spectrometry (GC-MS). The experimental results of ethyl acetate extraction showed that the monomers recovery efficiency was over 90%. This pre-treatment resulted in the removal of the major LMM phenolic compounds and a small part of HMM polyphenols. The aerobic treatment of the exhausted OMW fraction removed 78.7% of the soluble COD. In the case of anaerobic digestion at OLR ranged from 1 to 3.5 gCOD l(-1)day(-1), methanisation process exhibited high methane yield as 0.3 l CH4 produced per g COD introduced and high COD removal (80%). However, a disruption of the process was observed when the OLR was increased to 4.5 gCODl(-1)day(-1). A pre-treatment by electro-coagulation resulted in decreasing the toxicity and enhancing the performance of methanisation operated at higher OLR from 4 to 7.5 gCODl(-1)day(-1).

Building blocks for the development of an interface for high-throughput thin layer chromatography/ambient mass spectrometric analysis: a green methodology.

PubMed

Cheng, Sy-Chyi; Huang, Min-Zong; Wu, Li-Chieh; Chou, Chih-Chiang; Cheng, Chu-Nian; Jhang, Siou-Sian; Shiea, Jentaie

2012-07-17

Interfacing thin layer chromatography (TLC) with ambient mass spectrometry (AMS) has been an important area of analytical chemistry because of its capability to rapidly separate and characterize the chemical compounds. In this study, we have developed a high-throughput TLC-AMS system using building blocks to deal, deliver, and collect the TLC plate through an electrospray-assisted laser desorption ionization (ELDI) source. This is the first demonstration of the use of building blocks to construct and test the TLC-MS interfacing system. With the advantages of being readily available, cheap, reusable, and extremely easy to modify without consuming any material or reagent, the use of building blocks to develop the TLC-AMS interface is undoubtedly a green methodology. The TLC plate delivery system consists of a storage box, plate dealing component, conveyer, light sensor, and plate collecting box. During a TLC-AMS analysis, the TLC plate was sent to the conveyer from a stack of TLC plates placed in the storage box. As the TLC plate passed through the ELDI source, the chemical compounds separated on the plate would be desorbed by laser desorption and subsequently postionized by electrospray ionization. The samples, including a mixture of synthetic dyes and extracts of pharmaceutical drugs, were analyzed to demonstrate the capability of this TLC-ELDI/MS system for high-throughput analysis.

Effect of amino acids on the stability of spray freeze-dried immunoglobulin G in sugar-based matrices.

PubMed

Emami, Fakhrossadat; Vatanara, Alireza; Najafabadi, Abdolhosein Rouholamini; Kim, Yejin; Park, Eun Ji; Sardari, Soroush; Na, Dong Hee

2018-07-01

The purpose of this study was to prepare spray freeze-dried particles of immunoglobulin G (IgG) using various combinations of trehalose and different amino acids (leucine, phenylalanine, arginine, cysteine, and glycine), and investigate the effect of the amino acids on the stability of IgG during the spray freeze-drying (SFD) process and storage. The morphology and structural integrity of the processed particles were evaluated by physical and spectroscopic techniques. SFD-processed IgG without any excipient resulted in the formation of aggregates corresponding to approximately 14% of IgG. In contrast, IgG formulations stabilized using an optimal level of leucine, phenylalanine, or glycine in the presence of trehalose displayed aggregates <2.2%. In particular, phenylalanine combined with trehalose was most effective in stabilizing IgG against shear, freezing, and dehydration stresses during SFD. Arginine and cysteine were destabilizers displaying aggregation and fragmentation of IgG, respectively. Aggregation and fragmentation were evaluated by dynamic light scattering, ultraviolet spectrophotometry, size-exclusion chromatography, and microchip capillary gel electrophoresis. The IgG formulations prepared with leucine, phenylalanine, or glycine in the presence of trehalose showed good stability after storage at 40 °C and 75% relative humidity for 2 months. Thus, a combination of the excipients trehalose and uncharged, nonpolar amino acids appears effective for production of stable SFD IgG formulations. Copyright © 2018 Elsevier B.V. All rights reserved.

Release of lipoxygenase products and monoterpenes by tomato plants as an indicator of Botrytis cinerea-induced stress.

PubMed

Jansen, R M C; Miebach, M; Kleist, E; van Henten, E J; Wildt, J

2009-11-01

Changes in emission of volatile organic compounds (VOCs) from tomato induced by the fungus Botrytis cinerea were studied in plants inoculated by spraying with suspensions containing B. cinerea spores. VOC emissions were analysed using on-line gas chromatography-mass spectrometry, with a time resolution of about 1 h, for up to 2 days after spraying. Four phases were delimited according to the starting point and the applied day/night rhythm of the experiments. These phases were used to demonstrate changes in VOC flux caused by B. cinerea infestation. Tomato plants inoculated with B. cinerea emitted a different number and amount of VOCs after inoculation compared to control plants that had been sprayed with a suspension without B. cinerea spores. The changes in emissions were dependent on time after inoculation as well as on the severity of infection. The predominant VOCs emitted after inoculation were volatile products from the lipoxygenase pathway (LOX products). The increased emission of LOX products proved to be a strong indicator of a stress response, indicating that VOC emissions can be used to detect plant stress at an early stage. Besides emission of LOX products, there were also increases in monoterpene emissions. However, neither increased emission of LOX products nor of monoterpenes is specific for B. cinerea attack. The emission of LOX products is also induced by other stresses, and increased emission of monoterpenes seems to be the result of mechanical damage induced by secondary stress impacts on leaves.

Assessment of the dermal exposure to azoxystrobin among women tending cucumbers in selected Polish greenhouses after restricted entry intervals expired--the role of the protective gloves.

PubMed

Jurewicz, Joanna; Hanke, Wojciech; Sobala, Wojciech; Ligocka, Danuta

2009-01-01

The purpose of our study was to determine the level of skin contamination by azoxystrobin in a group of women tending cucumbers in a vegetable-growing greenhouse after restricted entry intervals expired. Exposure samples were assessed on two days during the spring: first entry on the day after spraying of azoxystrobin and second entry six days later. Dermal exposure was measured by using patches on the outside of clothing and sampling gloves underneath regular working gloves. Pesticide deposited on clothing patches and gloves as a substitute for skin deposition was determined by liquid chromatography and mass spectrometry (LC-MS/MS). The study has shown that workers in a Polish greenhouse are exposed to pesticides at re-entry into the greenhouse after pesticides were sprayed several days earlier. Azoxystrobin has been detected on hands, shoulders and chest. Higher levels of azoxystrobin were found on the cotton gloves of women tending the vegetables than on the patches. The levels decreased (by about 60%) on the patches and increased (by about 250%) on the cotton gloves between the two days of measurement. Women working in a vegetable-growing greenhouse and not directly engaged in the process of spraying experience a measurable dermal exposure to azoxystrobin. The protective gloves constitute a source of secondary exposure rather than protecting employees' hands from contact with the pesticide. More efficient personal protective gloves for proper protection of women working in vegetable greenhouses are needed.

Calcium phosphate coating on titanium using laser and plasma spray

NASA Astrophysics Data System (ADS)

Roy, Mangal

Though calcium phosphate (CaP) coated implants are commercially available, its acceptance is still not wide spread due to challenges related to weaker interfacial bonding between metal and ceramic, and low crystallinity of hydroxyapatite (HA). The objectives of this research are to improve interfacial strength, crystallinity, phase purity and bioactivity of CaP coated metallic implants for orthopaedic applications. The rationale is that forming a diffuse and gradient metal-ceramic interface will improve the interfacial strength. Moreover, reducing CaP particles exposure to high temperature during coating preparation, can lead to improvement in both crystallinity and phase purity of CaP. In this study, laser engineered net shaping (LENS(TM)) was used to coat Ti metal with CaP. LENS(TM) processing enabled generation of Ti+TCP (tricalcium phosphate) composite coating with diffused interface, that also increased the coating hardness to 1049+/-112 Hv compared to a substrate hardness of 200+/-15 Hv. In vitro bone cell-material interaction studies confirmed the bioactivity of TCP coatings. Antimicrobial properties of the TCP coatings were improved by silver (Ag) electrodeposition. Along with LENS(TM), radio frequency induction plasma spray, equipped with supersonic plasma nozzle, was used to prepare HA coatings on Ti with improved crystallinity and phase purity. The coating was made of multigrain HA particles of ˜200 nm in size, which consisted of 15--20 nm HA grains. In vitro bone cell-material interaction and in vivo rat model studies confirmed the HA coatings to be bioactive. Furthermore, incorporation of Sr2+ improved bone cell of HA coatings interaction. A combination of LENS(TM) and plasma spray was used to fabricate a compositionally graded HA coatings on Ti where the microstructure varied from pure HA at the surface to pure Ti substrate with a diffused Ti+TCP composite region in between. The plasma spray system was used to synthesize spherical HA nano powder from HA sol, where the production rate was 20 g/h, which is only 16% of the total powder produced. The effects of Sr2+ and Mg2+ doping on bone cell-CaP interaction was further studied with osteoclast cells. Mg2+ doing was found to be an effective way of controlling osteoclast differentiation.

High-pressure needle interface for thermoplastic microfluidics.

PubMed

Chen, C F; Liu, J; Hromada, L P; Tsao, C W; Chang, C C; DeVoe, D L

2009-01-07

A robust and low dead volume world-to-chip interface for thermoplastic microfluidics has been developed. The high pressure fluidic port employs a stainless steel needle inserted into a mating hole aligned to an embedded microchannel, with an interference fit used to increase pressure resistance. Alternately, a self-tapping threaded needle screwed into a mating hole is also demonstrated. In both cases, the flat bottom needle ports seat directly against the microchannel substrate, ensuring low interfacial dead volumes. Low dispersion is observed for dye bands passing the interfaces. The needle ports offer sufficient pull-out forces for applications such as liquid chromatography that require high internal fluid pressures, with the epoxy-free interfaces compatible with internal microchannel pressures above 40 MPa.

Induction of protective immunity against H1N1 influenza A(H1N1)pdm09 with spray-dried and electron-beam sterilised vaccines in non-human primates.

PubMed

Scherließ, Regina; Ajmera, Ankur; Dennis, Mike; Carroll, Miles W; Altrichter, Jens; Silman, Nigel J; Scholz, Martin; Kemter, Kristina; Marriott, Anthony C

2014-04-17

Currently, the need for cooled storage and the impossibility of terminal sterilisation are major drawbacks in vaccine manufacturing and distribution. To overcome current restrictions a preclinical safety and efficacy study was conducted to evaluate new influenza A vaccine formulations regarding thermal resistance, resistance against irradiation-mediated damage and storage stability. We evaluated the efficacy of novel antigen stabilizing and protecting solutions (SPS) to protect influenza A(H1N1)pdm09 split virus antigen under experimental conditions in vitro and in vivo. Original or SPS re-buffered vaccine (Pandemrix) was spray-dried and terminally sterilised by irradiation with 25 kGy (e-beam). Antigen integrity was monitored by SDS-PAGE, dynamic light scattering, size exclusion chromatography and functional haemagglutination assays. In vitro screening experiments revealed a number of highly stable compositions containing glycyrrhizinic acid (GA) and/or chitosan. The most stable composition was selected for storage tests and in vivo assessment of seroconversion in non-human primates (Macaca fascicularis) using a prime-boost strategy. Redispersed formulations with original adjuvant were administered intramuscularly. Storage data revealed high stability of protected vaccines at 4°C and 25°C, 60% relative humidity, for at least three months. Animals receiving original Pandemrix exhibited expected levels of seroconversion after 21 days (prime) and 48 days (boost) as assessed by haemagglutination inhibition and microneutralisation assays. Animals vaccinated with spray-dried and irradiated Pandemrix failed to exhibit seroconversion after 21 days whereas spray-dried and irradiated, SPS-protected vaccines elicited similar seroconversion levels to those vaccinated with original Pandemrix. Boost immunisation with SPS-protected vaccine resulted in a strong increase in seroconversion but had only minor effects in animals treated with non SPS-protected vaccine. In conclusion, utilising the SPS formulation technology, spray-drying and terminal sterilisation of influenza A(H1N1)pdm09 split virus vaccine is feasible. Findings indicate the potential utility of such formulated vaccines e.g. for needle-free vaccination routes and delivery to countries with uncertain cold chain facilities. Copyright © 2014 Elsevier Ltd. All rights reserved.

ANALYSIS OF SELECTED CHEMICAL GROUPS BY LIQUID CHROMATOGRAPHY/MASS SPECTROMETRY

EPA Science Inventory

The use of the moving-belt liquid chromatographic interface in combination with mass spectrometry was evaluated for determining detection limits of selected members of various chemical classes. mong the chemical classes examined were benzidines, nitrosoamines, anilines, nitroarom...

Cooling Performance of a Partially-Confined FC-72 Spray: The Effect of Dissolved Air (Postprint)

DTIC Science & Technology

2007-01-01

plate FC = FC-72 fluid htr = heater conductive layer int = interface between heater substrate and insulating support post m = measured s = heater... microporous enhanced surface and a plain reference surface, and developed correlations for nucleate boiling and CHF. The results of the experiment...8Rainey, K. N., You, S. M., and Lee, S., “Effect of Pressure, Subcooling, and Dissolved Gas on Pool Boiling Heat Transfer from Microporous Surfaces

The effects of mannitol on the transport of ciprofloxacin across respiratory epithelia.

PubMed

Ong, Hui Xin; Traini, Daniela; Salama, Rania; Anderson, Sandra D; Daviskas, Evangelia; Young, Paul M

2013-08-05

Inhalation of antibiotics and mucolytics is the most important combination of inhaled drugs for chronic obstructive lung diseases and has become a standard part of treatment. However, it is yet to be determined whether the administration of a mucolytic has an effect on the transport rate of antibiotics across the airway epithelial cells. Consequently, the aim of this study was to investigate the effects of inhalation dry powder, specifically mannitol, on ciprofloxacin transport using a Calu-3 air-interface cell model. Transport studies of ciprofloxacin HCl were performed using different configurations including single spray-dried ciprofloxacin alone, co-spray-dried ciprofloxacin with mannitol, and deposition of mannitol prior to ciprofloxacin deposition. To understand the mechanism of transport and interactions between the drugs, pH measurements of apical surface liquid (ASL) and further transport studies were performed with ciprofloxacin base, with and without the presence of ion channel/transport inhibitors such as disodium cromoglycate and furosemide. Mannitol was found to delay absorption of ciprofloxacin HCl through the increase in ASL volume and subsequent reduction in pH. Conversely, ciprofloxacin base had a higher transport rate after mannitol deposition. This study clearly demonstrates that the deposition of mannitol prior to ciprofloxacin on the air-interface Calu-3 cell model has an effect on its transport rate. This was also dependent on the salt form of the drug and the timing and sequence of formulations administered.

Liquid chromatography/Fourier transform IR spectrometry interface flow cell

DOEpatents

Johnson, Charles C.; Taylor, Larry T.

1986-01-01

A zero dead volume (ZDV) microbore high performance liquid chromatography (.mu.HPLC)/Fourier transform infrared (FTIR) interface flow cell includes an IR transparent crystal having a small diameter bore therein through which a sample liquid is passed. The interface flow cell further includes a metal holder in combination with a pair of inner, compressible seals for directly coupling the thus configured spectrometric flow cell to the outlet of a .mu.HPLC column end fitting to minimize the transfer volume of the effluents exiting the .mu.HPLC column which exhibit excellent flow characteristics due to the essentially unencumbered, open-flow design. The IR beam passes transverse to the sample flow through the circular bore within the IR transparent crystal, which is preferably comprised of potassium bromide (KBr) or calcium fluoride (CaF.sub.2), so as to minimize interference patterns and vignetting encountered in conventional parallel-plate IR cells. The long IR beam pathlength and lensing effect of the circular cross-section of the sample volume in combination with the refractive index differences between the solvent and the transparent crystal serve to focus the IR beam in enhancing sample detection sensitivity by an order of magnitude.

Liquid chromatography/Fourier transform IR spectrometry interface flow cell

DOEpatents

Johnson, C.C.; Taylor, L.T.

1985-01-04

A zero dead volume (ZDV) microbore high performance liquid chromatography (..mu.. HPLC)/Fourier transform infrared (FTIR) interface flow cell includes an IR transparent crystal having a small diameter bore therein through which a sample liquid is passed. The interface flow cell further includes a metal holder in combination with a pair of inner, compressible seals for directly coupling the thus configured spectrometric flow cell to the outlet of a ..mu.. HPLC column end fitting to minimize the transfer volume of the effluents exiting the ..mu.. HPLC column which exhibit excellent flow characteristics due to the essentially unencumbered, open-flow design. The IR beam passes transverse to the sample flow through the circular bore within the IR transparent crystal, which is preferably comprised of potassium bromide (KBr) or calcium fluoride (CaF/sub 2/), so as to minimize interference patterns and vignetting encountered in conventional parallel-plate IR cells. The long IR beam pathlength and lensing effect of the circular cross-section of the sample volume in combination with the refractive index differences between the solvent and the transparent crystal serve to focus the IR beam in enhancing sample detection sensitivity by an order of magnitude.

The offline combination of thin-layer chromatography and high-performance liquid chromatography with diode array detection and micrOTOF-Q mass spectrometry for the separation and identification of spinochromes from sea urchin (Strongylocentrotus droebachiensis) shells.

PubMed

Shikov, Alexander N; Ossipov, Vladimir I; Martiskainen, Olli; Pozharitskaya, Olga N; Ivanova, Svetlana A; Makarov, Valery G

2011-12-16

Thin-layer chromatography (TLC) with off-line high-performance liquid chromatography coupled to diode array detection and micrOTOF-Q mass spectrometry (HPLC-DAD-MS) resulted in the successful fractionation, separation and identification of spinochrome pigments from sea urchin (Strongylocentrotus droebachiensis) shells. Two fractions of pigments were separated by TLC and eluted with methanol using a TLC-MS interface. HPLC-DAD-MS analysis of the fractions indicated the presence of six sea urchin pigments: spinochrome monomers B and D, three spinochrome dimers (anhydroethylidene-6,6'-bis(2,3,7-trihydroxynaphthazarin) and its isomer and ethylidene-6,6'-bis(2,3,7-trihydroxynaphthazarin)), and one pigment that was preliminary identified as a spinochrome dimer with the structural formula C(22)H(16)O(16). Copyright © 2011 Elsevier B.V. All rights reserved.

Micro-polarimeter for high performance liquid chromatography

DOEpatents

Yeung, Edward E.; Steenhoek, Larry E.; Woodruff, Steven D.; Kuo, Jeng-Chung

1985-01-01

A micro-polarimeter interfaced with a system for high performance liquid chromatography, for quantitatively analyzing micro and trace amounts of optically active organic molecules, particularly carbohydrates. A flow cell with a narrow bore is connected to a high performance liquid chromatography system. Thin, low birefringence cell windows cover opposite ends of the bore. A focused and polarized laser beam is directed along the longitudinal axis of the bore as an eluent containing the organic molecules is pumped through the cell. The beam is modulated by air gap Faraday rotators for phase sensitive detection to enhance the signal to noise ratio. An analyzer records the beams's direction of polarization after it passes through the cell. Calibration of the liquid chromatography system allows determination of the quantity of organic molecules present from a determination of the degree to which the polarized beam is rotated when it passes through the eluent.

In-situ synchrotron micro-diffraction study of surface, interface, grain structure, and strain/stress evolution during Sn whisker/hillock formation

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

Pei, Fei; Jadhav, Nitin; Buchovecky, Eric

2016-03-14

We have performed X-ray synchrotron micro-diffraction measurements to study the processes controlling the formation of hillocks and whiskers in Sn layers on Cu. The studies were done in real-time on Sn layers that were electro-deposited immediately before the X-ray measurements were started. This enabled a region of the sample to be monitored from the as-deposited state until after a hillock feature formed. In addition to measuring the grain orientation and deviatoric strain (via Laue diffraction), the X-ray fluorescence was monitored to quantify the evolution of the Sn surface morphology and the formation of intermetallic compound (IMC) at the Sn-Cu interface.more » The results capture the simultaneous growth of the feature and the corresponding film stress, grain orientation, and IMC formation. The observations are compared with proposed mechanisms for whisker/hillock growth and nucleation.« less