High surface area, electrically conductive nanocarbon-supported metal oxide

DOEpatents

Worsley, Marcus A.; Han, Thomas Yong-Jin; Kuntz, Joshua D.; Cervantes, Octavio; Gash, Alexander E.; Baumann, Theodore F.; Satcher, Jr., Joe H.

2015-07-14

A metal oxide-carbon composite includes a carbon aerogel with an oxide overcoat. The metal oxide-carbon composite is made by providing a carbon aerogel, immersing the carbon aerogel in a metal oxide sol under a vacuum, raising the carbon aerogel with the metal oxide sol to atmospheric pressure, curing the carbon aerogel with the metal oxide sol at room temperature, and drying the carbon aerogel with the metal oxide sol to produce the metal oxide-carbon composite. The step of providing a carbon aerogel can provide an activated carbon aerogel or provide a carbon aerogel with carbon nanotubes that make the carbon aerogel mechanically robust.

High surface area, electrically conductive nanocarbon-supported metal oxide

DOEpatents

Worsley, Marcus A; Han, Thomas Yong-Jin; Kuntz, Joshua D; Cervanted, Octavio; Gash, Alexander E; Baumann, Theodore F; Satcher, Jr., Joe H

2014-03-04

A metal oxide-carbon composite includes a carbon aerogel with an oxide overcoat. The metal oxide-carbon composite is made by providing a carbon aerogel, immersing the carbon aerogel in a metal oxide sol under a vacuum, raising the carbon aerogel with the metal oxide sol to atmospheric pressure, curing the carbon aerogel with the metal oxide sol at room temperature, and drying the carbon aerogel with the metal oxide sol to produce the metal oxide-carbon composite. The step of providing a carbon aerogel can provide an activated carbon aerogel or provide a carbon aerogel with carbon nanotubes that make the carbon aerogel mechanically robust.

75 FR 70962 - California Green Trade Corridor Transportation Investment Generating Economic Recovery (TIGER)

Federal Register 2010, 2011, 2012, 2013, 2014

2010-11-19

... Final EA and Finding of No Significant Impact can be obtained or viewed online at http:[sol][sol]www..., users need to obtain a free copy of Acrobat Reader. The Acrobat Reader can be obtained from http:[sol][sol]www.adobe.com/ prodindex/acrobat/readstep.html. By order of the Maritime Administrator. Dated...

Improvement of Sol-Gel Derived PbZrxTi1-xO3 Film Properties Using Thermal Press Treatment

NASA Astrophysics Data System (ADS)

Kaneda, Toshihiko; Kim, Joo-Nam; Tokumitsu, Eisuke; Shimoda, Tatsuya

2010-09-01

A thermal press treatment was introduced in the sol-gel process of PbZrxTi1-xO3 (PZT) thin films for the first time and the crystalline and electrical characteristics of the PZT films were investigated. The thermal press treatment was applied to the amorphous PZT gel film before crystallization annealing. It is found that the crystalline orientation and grain size of the PZT film fabricated with the thermal press treatment are different from those of the film fabricated by the conventional sol-gel process without the thermal press treatment, even though the crystallization conditions are exactly the same. It is demonstrated that the electrical properties, especially leakage current density and breakdown field, are significantly improved for the PZT film fabricated with the thermal press treatment. Furthermore, we also demonstrate that the fatigue property is improved by introducing the thermal press treatment.

Growth and Characterization of CuO Nanostructures on Si for the Fabrication of CuO/p-Si Schottky Diodes

PubMed Central

Çetinkaya, S.; Çetinkara, H. A.; Bayansal, F.; Kahraman, S.

2013-01-01

CuO interlayers in the CuO/p-Si Schottky diodes were fabricated by using CBD and sol-gel methods. Deposited CuO layers were characterized by SEM and XRD techniques. From the SEM images, it was seen that the film grown by CBD method is denser than the film grown by sol-gel method. This result is compatible with XRD results which show that the crystallization in CBD method is higher than it is in sol-gel method. For the electrical investigations, current-voltage characteristics of the diodes have been studied at room temperature. Conventional I-V and Norde's methods were used in order to determine the ideality factor, barrier height, and series resistance values. It was seen that the morphological and structural analysis are compatible with the results of electrical investigations. PMID:23766670

Selective recruitment of the triceps surae muscles with changes in knee angle.

PubMed

Signorile, Joseph F; Applegate, Brooks; Duque, Maurice; Cole, Natalie; Zink, Attila

2002-08-01

The muscles of the triceps surae group are important for performance in most sports and in the performance of activities of daily life. In addition, hypertrophy and balance among these muscles are integral to success in bodybuilding. The purpose of this study was to compare the muscle utilization patterns of the 2 major muscles of the triceps surae group, the soleus (SOL) and gastrocnemius (lateral head = LG and medial head = MG), and the tibialis anterior (TA) as an antagonist muscle to the group. Their electromyographic (EMG) signals were compared during 50 constant external resistance contractions at a level established before the testing session. Eleven experienced subjects contributed data during plantar flexion at 3 different knee angles (90, 135, and 180 degrees ). Both root mean square amplitude and integrated signal analyses of the EMGs revealed that the MG produced significantly greater activity than either the SOL or TA at 180 degrees, whereas the LG was not different from the SOL at any knee angle measured. Data also revealed that the SOL produced less electrical activity at 180 degrees than at the other knee angles, whereas the MG produced greater electrical activity. As would be expected, the TA produced lower EMG values than any of the triceps surae muscles at all angles tested. These data indicate that selective targeting of the SOL and MG is possible through the manipulation of knee angle. This targeting appears to be controlled by the biarticular and monoarticular structures of the MG and SOL, respectively. The LG appears less affected by knee position than the MG. Results suggest that the SOL can be targeted most effectively with the knee flexed at 90 degrees and the MG with the leg fully extended. The LG appears to also be more active at 180 degrees; however, it is not as affected as the MG or SOL by knee angle.

Athermal silicon optical add-drop multiplexers based on thermo-optic coefficient tuning of sol-gel material.

PubMed

Namnabat, Soha; Kim, Kyung-Jo; Jones, Adam; Himmelhuber, Roland; DeRose, Christopher T; Trotter, Douglas C; Starbuck, Andrew L; Pomerene, Andrew; Lentine, Anthony L; Norwood, Robert A

2017-09-04

Silicon photonics has gained interest for its potential to provide higher efficiency, bandwidth and reduced power consumption compared to electrical interconnects in datacenters and high performance computing environments. However, it is well known that silicon photonic devices suffer from temperature fluctuations due to silicon's high thermo-optic coefficient and therefore, temperature control in many applications is required. Here we present an athermal optical add-drop multiplexer fabricated from ring resonators. We used a sol-gel inorganic-organic hybrid material as an alternative to previously used materials such as polymers and titanium dioxide. In this work we studied the thermal curing parameters of the sol-gel and their effect on thermal wavelength shift of the rings. With this method, we were able to demonstrate a thermal shift down to -6.8 pm/°C for transverse electric (TE) polarization in ring resonators with waveguide widths of 325 nm when the sol-gel was cured at 130°C for 10.5 hours. We also achieved thermal shifts below 1 pm/°C for transverse magnetic (TM) polarization in the C band under different curing conditions. Curing time compared to curing temperature shows to be the most important factor to control sol-gel's thermo-optic value in order to obtain an athermal device in a wide temperature range.

Effects of lithium doping on microstructure, electrical properties, and chemical bonds of sol-gel derived NKN thin films

NASA Astrophysics Data System (ADS)

Lin, Chun-Cheng; Chen, Chan-Ching; Weng, Chung-Ming; Chu, Sheng-Yuan; Hong, Cheng-Shong; Tsai, Cheng-Che

2015-02-01

Highly (100/110) oriented lead-free Lix(Na0.5K0.5)1-xNbO3 (LNKN, x = 0, 0.02, 0.04, and 0.06) thin films are fabricated on Pt/Ti/SiO2/Si substrates via a sol-gel processing method. The lithium (Li) dopants modify the microstructure and chemical bonds of the LNKN films, and therefore improve their electrical properties. The optimal values of the remnant polarization (Pr = 14.3 μC/cm2), piezoelectric coefficient (d33 = 48.1 pm/V), and leakage current (<10-5 A/cm2) are obtained for a lithium addition of x = 0.04 (i.e., 4 at. %). The observation results suggest that the superior electrical properties are the result of an improved crystallization, a larger grain size, and a smoother surface morphology. It is shown that the ion transport mechanism is dominated by an Ohmic behavior under low electric fields and the Poole-Frenkel emission effect under high electric fields.

From core to coax: extending core RF modelling to include SOL, Antenna, and PFC

NASA Astrophysics Data System (ADS)

Shiraiwa, Syun'ichi

2017-10-01

A new technique for the calculation of RF waves in toroidal geometry enables the simultaneous incorporation of antenna geometry, plasma facing components (PFCs), the scrape off-layer (SOL), and core propagation. Traditionally, core RF wave propagation and antenna coupling has been calculated separately both using rather simplified SOL plasmas. The new approach, instead, allows capturing wave propagation in the SOL and its interactions with non-conforming PFCs permitting self-consistent calculation of core absorption and edge power loss, as well as investigating far and near field impurity generation from RF sheaths and a breakdown issue from antenna electric fields. Our approach combines the field solutions obtained from a core spectral code with a hot plasma dielectric and an edge FEM code using a cold plasma approximation via surface admittance-like matrix. Our approach was verified using the TORIC core ICRF spectral code and the commercial COMSOL FEM package, and was extended to 3D torus using open-source scalable MFEM library. The simulation result revealed that as the core wave damping gets weaker, the wave absorption in edge could become non-negligible. Three dimensional capabilities with non axisymmetric edge are being applied to study the antenna characteristic difference between the field aligned and toroidally aligned antennas on Alcator C-Mod, as well as the surface wave excitation on NSTX-U. Work supported by the U.S. DoE, OFES, using User Facility Alcator C-Mod, DE-FC02-99ER54512 and Contract No. DE-FC02-01ER54648.

Sol-gel preparation of Ag-silica nanocomposite with high electrical conductivity

NASA Astrophysics Data System (ADS)

Ma, Zhijun; Jiang, Yuwei; Xiao, Huisi; Jiang, Bofan; Zhang, Hao; Peng, Mingying; Dong, Guoping; Yu, Xiang; Yang, Jian

2018-04-01

Sol-gel derived noble-metal-silica nanocomposites are very useful in many applications. Due to relatively low price, higher conductivity, and higher chemical stability of silver (Ag) compared with copper (Cu), Ag-silica has gained much more research interest. However, it remains a significant challenge to realize high loading of Ag content in sol-gel Ag-silica composite with high structural controllability and nanoparticles' dispersity. Different from previous works by using multifunctional silicon alkoxide to anchor metal ions, here we report the synthesis of Ag-silica nanocomposite with high loading of Ag nanoparticles by employing acetonitrile bi-functionally as solvent and metal ions stabilizer. The electrical conductivity of the Ag-silica nanocomposite reached higher than 6800 S/cm. In addition, the Ag-silica nanocomposite could simultaneously possess high electrical conductivity and positive conductivity-temperature coefficient by properly controlling the loading content of Ag. Such behavior is potentially advantageous for high-temperature devices (like phosphoric acid fuel cells) and inhibiting the thermal-induced increase of devices' internal resistance. The strategy proposed here is also compatible with block-copolymer directed self-assembly of mesoporous material, spin-coating of film and electrospinning of nanofiber, making it more charming in various practical applications.

Red cell storage in E-Sol 5 and Adsol additive solutions: paired comparison using mixed and non-mixed study designs.

PubMed

Radwanski, K; Thill, M; Min, K

2014-05-01

If transfusion of older stored red cells is found to negatively affect clinical outcome, one possible alternative to shortened outdate is the use of new additive solutions (AS) that ameliorate the storage lesion. Erythro-Sol (E-Sol), a previously developed next-generation AS, has been reformulated into E-Sol 5, which is compatible with current anticoagulants and AS volumes. The effect of E-Sol 5 on red cells during storage compared to current AS has not been reported. Paired, ABO-matched whole-blood units were collected into CPD anticoagulant, pooled, split and processed into plasma and red cell units with either 110 ml of Adsol or 105 ml of E-Sol 5 within 8 h of collection. In Study 1, paired units in E-Sol 5 and Adsol were sampled on Day 0 and every 7 days up to Day 42 (n = 10). In Study 2, paired units in E-Sol 5 and Adsol were sampled only on Day 0 and Day 42 (n = 10). In Study 1, 2,3 DPG levels were maintained until Day 28 in E-Sol 5 units and Day 14 in Adsol units. ATP levels were higher in E-Sol 5 units until Day 21, after which they were comparable between the two groups. In both studies, metabolic activity was greater in E-Sol 5 units with respect to glucose consumption and lactate production. Morphology scores were higher, and haemolysis and microparticles generated were lower in E-Sol 5 vs. Adsol units. Weekly mixing of units lowered haemolysis and microparticle levels and increased potassium content on Day 42 in both additive solutions. Regardless of whether units are mixed weekly or are stored non-mixed, E-Sol 5 slows the progression of the red cell storage lesion and improves the overall in vitro quality of RBC throughout storage. © 2013 International Society of Blood Transfusion.

Method of making ionic liquid mediated sol-gel sorbents

DOEpatents

Malik, Abdul; Shearrow, Anne M.

2017-01-31

Ionic liquid (IL)-mediated sol-gel hybrid organic-inorganic materials present enormous potential for effective use in analytical microextraction. One obstacle to materializing this prospect arises from high viscosity of ILs significantly slowing down sol-gel reactions. A method was developed which provides phosphonium-based, pyridinium-based, and imidazolium-based IL-mediated advanced sol-gel organic-inorganic hybrid materials for capillary microextraction. Scanning electron microscopy results demonstrate that ILs can serve as porogenic agents in sol-gel reactions. IL-mediated sol-gel coatings prepared with silanol-terminated polymers provided up to 28 times higher extractions compared to analogous sol-gel coatings prepared without any IL in the sol solution. This study shows that IL-generated porous morphology alone is not enough to provide effective extraction media: careful choice of the organic polymer and the precursor with close sol-gel reactivity must be made to ensure effective chemical bonding of the organic polymer to the created sol-gel material to be able to provide the desired sorbent characteristics.

Optical, electrical and dielectric properties of TiO2-SiO2 films prepared by a cost effective sol-gel process.

PubMed

Vishwas, M; Rao, K Narasimha; Gowda, K V Arjuna; Chakradhar, R P S

2011-12-01

Titanium dioxide (TiO(2)) and silicon dioxide (SiO(2)) thin films and their mixed films were synthesized by the sol-gel spin coating method using titanium tetra isopropoxide (TTIP) and tetra ethyl ortho silicate (TEOS) as the precursor materials for TiO(2) and SiO(2) respectively. The pure and composite films of TiO(2) and SiO(2) were deposited on glass and silicon substrates. The optical properties were studied for different compositions of TiO(2) and SiO(2) sols and the refractive index and optical band gap energies were estimated. MOS capacitors were fabricated using TiO(2) films on p-silicon (100) substrates. The current-voltage (I-V) and capacitance-voltage (C-V) characteristics were studied and the electrical resistivity and dielectric constant were estimated for the films annealed at 200°C for their possible use in optoelectronic applications. Copyright © 2011 Elsevier B.V. All rights reserved.

Sol-gel derived CaCu{sub 3}Ti{sub 4}O{sub 12} ceramics: Synthesis, characterization and electrical properties

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

Liu Laijun; Fan Huiqing; Fang Pinyang

2008-07-01

The giant dielectric constant material CaCu{sub 3}Ti{sub 4}O{sub 12} (CCTO) has been synthesized by sol-gel method, for the first time, using nitrate and alkoxide precursor. The electrical properties of CCTO ceramics, showing an enormously large dielectric constant {epsilon} {approx} 60,000 (100 Hz at RT), were investigated in the temperature range from 298 to 358 K at 0, 5, 10, 20, and 40 V dc. The phases, microstructures, and impedance properties of final samples were characterized by X-ray diffraction, scanning electron microscopy, and precision impedance analyzer. The dielectric permittivity of CCTO synthesized by sol-gel method is at least three times ofmore » magnitude larger than that synthesized by other low-temperature method and solid-state reaction method. Furthermore, the results support the internal barrier layer capacitor (IBLC) model of Schottky barriers at grain boundaries between semiconducting grains.« less

Spirit Near 'Stapledon' on Sol 1802 (Vertical)

NASA Technical Reports Server (NTRS)

2009-01-01

NASA Mars Exploration Rover Spirit used its navigation camera for the images assembled into this full-circle view of the rover's surroundings during the 1,802nd Martian day, or sol, (January 26, 2009) of Spirit's mission on the surface of Mars. North is at the top.

This view is presented as a vertical projection with geometric seam correction.

Spirit had driven down off the low plateau called 'Home Plate' on Sol 1782 (January 6, 2009) after spending 12 months on a north-facing slope on the northern edge of Home Plate. The position on the slope (at about the 9-o'clock position in this view) tilted Spirit's solar panels toward the sun, enabling the rover to generate enough electricity to survive its third Martian winter. Tracks at about the 11-o'clock position of this panorama can be seen leading back to that 'Winter Haven 3' site from the Sol 1802 position about 10 meters (33 feet) away. For scale, the distance between the parallel wheel tracks is about one meter (40 inches).

Where the receding tracks bend to the left, a circular pattern resulted from Spirit turning in place at a soil target informally named 'Stapledon' after William Olaf Stapledon, a British philosopher and science-fiction author who lived from 1886 to 1950. Scientists on the rover team suspected that the soil in that area might have a high concentration of silica, resembling a high-silica soil patch discovered east of Home Plate in 2007. Bright material visible in the track furthest to the right was examined with Spirit's alpha partical X-ray spectrometer and found, indeed, to be rich in silica.

The team laid plans to drive Spirit from this Sol 1802 location back up onto Home Plate, then southward for the rover's summer field season.

Spirit Near 'Stapledon' on Sol 1802

NASA Technical Reports Server (NTRS)

2009-01-01

NASA Mars Exploration Rover Spirit used its navigation camera for the images assembled into this full-circle view of the rover's surroundings during the 1,802nd Martian day, or sol, (January 26, 2009) of Spirit's mission on the surface of Mars. South is at the center; north is at both ends.

Spirit had driven down off the low plateau called 'Home Plate' on Sol 1782 (January 6, 2009) after spending 12 months on a north-facing slope on the northern edge of Home Plate. The position on the slope (at about the 9-o'clock position in this view) tilted Spirit's solar panels toward the sun, enabling the rover to generate enough electricity to survive its third Martian winter. Tracks at about the 11-o'clock position of this panorama can be seen leading back to that 'Winter Haven 3' site from the Sol 1802 position about 10 meters (33 feet) away. For scale, the distance between the parallel wheel tracks is about one meter (40 inches).

Where the receding tracks bend to the left, a circular pattern resulted from Spirit turning in place at a soil target informally named 'Stapledon' after William Olaf Stapledon, a British philosopher and science-fiction author who lived from 1886 to 1950. Scientists on the rover team suspected that the soil in that area might have a high concentration of silica, resembling a high-silica soil patch discovered east of Home Plate in 2007. Bright material visible in the track furthest to the right was examined with Spirit's alpha partical X-ray spectrometer and found, indeed, to be rich in silica.

The team laid plans to drive Spirit from this Sol 1802 location back up onto Home Plate, then southward for the rover's summer field season.

This view is presented as a cylindrical projection with geometric seam correction.

Spirit Near 'Stapledon' on Sol 1802 (Polar)

NASA Technical Reports Server (NTRS)

2009-01-01

NASA Mars Exploration Rover Spirit used its navigation camera for the images assembled into this full-circle view of the rover's surroundings during the 1,802nd Martian day, or sol, (January 26, 2009) of Spirit's mission on the surface of Mars. North is at the top.

This view is presented as a polar projection with geometric seam correction.

Spirit had driven down off the low plateau called 'Home Plate' on Sol 1782 (January 6, 2009) after spending 12 months on a north-facing slope on the northern edge of Home Plate. The position on the slope (at about the 9-o'clock position in this view) tilted Spirit's solar panels toward the sun, enabling the rover to generate enough electricity to survive its third Martian winter. Tracks at about the 11-o'clock position of this panorama can be seen leading back to that 'Winter Haven 3' site from the Sol 1802 position about 10 meters (33 feet) away. For scale, the distance between the parallel wheel tracks is about one meter (40 inches).

Where the receding tracks bend to the left, a circular pattern resulted from Spirit turning in place at a soil target informally named 'Stapledon' after William Olaf Stapledon, a British philosopher and science-fiction author who lived from 1886 to 1950. Scientists on the rover team suspected that the soil in that area might have a high concentration of silica, resembling a high-silica soil patch discovered east of Home Plate in 2007. Bright material visible in the track furthest to the right was examined with Spirit's alpha partical X-ray spectrometer and found, indeed, to be rich in silica.

The team laid plans to drive Spirit from this Sol 1802 location back up onto Home Plate, then southward for the rover's summer field season.

Preparation and Optoelectrical Properties of p-CuO/n-Si Heterojunction by a Simple Sol-Gel Method

NASA Astrophysics Data System (ADS)

He, Bo; Xu, Jing; Ning, Huanpo; Zhao, Lei; Xing, Huaizhong; Chang, Chien-Cheng; Qin, Yuming; Zhang, Lei

The Cuprous oxide (CuO) thin film was prepared on texturized Si wafer by a simple sol-gel method to fabricate p-CuO/n-Si heterojunction photoelectric device. The novel sol-gel method is very cheap and convenient. The structural, optical and electrical properties of the CuO film were studied by X-ray diffraction (XRD), Scanning Electron Microscope (SEM), X-ray photoelectron spectroscopy (XPS), UV-Vis spectrophotometer and Hall effect measurement. A good nonlinear rectifying behavior is obtained for the p-CuO/n-Si heterojunction. Under reverse bias, good photoelectric behavior is obtained.

Increasing the activity and enantioselectivity of lipases by sol-gel immobilization: further advancements of practical interest

NASA Astrophysics Data System (ADS)

Tielmann, Patrick; Kierkels, Hans; Zonta, Albin; Ilie, Adriana; Reetz, Manfred T.

2014-05-01

The entrapment of lipases in hydrophobic silicate matrices formed by sol-gel mediated hydrolysis of RSi(OCH3)3/Si(OCH3)4 as originally reported in 1996 has been improved over the years by a number of modifications. In the production of second-generation sol-gel lipase immobilizates, a variety of additives during the sol-gel process leads to increased activity and enhanced stereoselectivity in esterifying kinetic resolution. Recent advances in this type of lipase immobilization are reviewed here, in addition to new results regarding the sol-gel entrapment of the lipase from Burkholderia cepacia. It constitutes an excellent heterogeneous biocatalyst in the acylating kinetic resolution of two synthetically and industrially important chiral alcohols, rac-sulcatol and rac-trans-2-methoxycyclohexanol. The observation that the catalyst can be used 10 times in recycling experiments without losing its significant activity or enantioselectivity demonstrates the practical viability of the sol-gel approach.The entrapment of lipases in hydrophobic silicate matrices formed by sol-gel mediated hydrolysis of RSi(OCH3)3/Si(OCH3)4 as originally reported in 1996 has been improved over the years by a number of modifications. In the production of second-generation sol-gel lipase immobilizates, a variety of additives during the sol-gel process leads to increased activity and enhanced stereoselectivity in esterifying kinetic resolution. Recent advances in this type of lipase immobilization are reviewed here, in addition to new results regarding the sol-gel entrapment of the lipase from Burkholderia cepacia. It constitutes an excellent heterogeneous biocatalyst in the acylating kinetic resolution of two synthetically and industrially important chiral alcohols, rac-sulcatol and rac-trans-2-methoxycyclohexanol. The observation that the catalyst can be used 10 times in recycling experiments without losing its significant activity or enantioselectivity demonstrates the practical viability of the sol-gel approach. Dedicated to the pioneer of sol-gel enzyme immobilization, Professor David Avnir, on the occasion of his 65th birthday.

Enhanced self-repairing capability of sol-gel derived SrTiO3/nano Al2O3 composite films

NASA Astrophysics Data System (ADS)

Yao, Manwen; Peng, Yong; Xiao, Ruihua; Li, Qiuxia; Yao, Xi

2016-08-01

SrTiO3/nano Al2O3 inorganic nanocomposites were prepared by using a conventional sol-gel spin coating process. For comparison, SrTiO3 films doped by equivalent amount of sol-Al2O3 have also been investigated. Aluminum deposited by using vacuum evaporation was used as the top electrode. The nanocomposites exhibited a significantly enhanced dielectric strength of 506.9 MV/m, which was increased by 97.4% as compared with the SrTiO3 films doped with sol-Al2O3. The leakage current maintained of the same order of microampere until the ultimate breakdown of the nanocomposites. The excellent electrical performances are ascribed to the anodic oxidation reaction in origin, which can repair the internal and/or surface defects of the films.

Growth and characterization of sol-gel derived CuGaO2 semiconductor thin films for UV photodetector application

NASA Astrophysics Data System (ADS)

Tsay, Chien-Yie; Chen, Ching-Lien

2017-06-01

In this study, a p-type wide-bandgap oxide semiconductor CuGaO2 thin film was grown on quartz substrate by sol-gel method. The authors report the influence of annealing temperature on the phase transformation, structural features, and electrical properties of sol-gel derived Cu-Ga-O thin films. At relatively low annealing temperatures (≤900 °C), the films are a mixture of CuGa2O4, CuGaO2, and CuO phases. At relatively high annealing temperatures (≥925 °C), the majority phase in the films is delafossite CuGaO2. All as-prepared Cu-Ga-O thin films exhibited p-type conductivity, as confirmed by Hall measurements. The mean electrical resistivity of the Cu-Ga-O films decreased from 3.54×104 Ω-cm to 1.35×102 Ω-cm and then increased slightly to 3.51×102 Ω-cm when the annealing temperature was increased from 850 °C to 950 °C. We found that annealing the Cu-based oxide thin films at 925 °C produced nearly phase-pure CuGaO2 thin films with good densification. Such thin films exhibited the best electrical properties: a mean electrical resistivity of 1.35×102 Ω-cm, and a mean hole concentration of 1.60×1016 cm-3. In addition, we also fabricated and characterized MSM-type CuGaO2 UV photodetectors on quartz substrates.

Ecological differentiation within a cosmopolitan group of planktonic freshwater bacteria (SOL cluster, Saprospiraceae, Bacteroidetes).

PubMed

Schauer, Michael; Kamenik, Christian; Hahn, Martin W

2005-10-01

Members of the monophyletic SOL cluster are large filamentous bacteria inhabiting the pelagic zone of many freshwater habitats. The abundances of SOL bacteria and compositions of SOL communities in samples from 115 freshwater ecosystems around the globe were determined by fluorescence in situ hybridization with cluster- and subcluster-specific oligonucleotide probes. The vast majority (73%) of sampled ecosystems harbored SOL bacteria, and all three previously described SOL subclusters (LD2, HAL, and GKS2-217) were detected. The morphometric and chemicophysical parameters and trophic statuses of ecosystems were related to the occurrence and subcluster-specific composition of SOL bacteria by multivariate statistical methods. SOL bacteria did not occur in acidic lakes (pH < 6), and their abundance was negatively related to high trophy and pH. The subcluster-specific variation in the compositions of SOL communities could be related to the pH, electrical conductivity, altitude, and trophic status of ecosystems. All three known SOL subclusters differed in respect to their tolerated ranges of pH and conductivity. Complete niche separation was observed between the vicarious subclusters GKS2-217 and LD2; the former occurred in soft-water lakes, whereas the latter was found in a broad range of hard-water habitats. The third subgroup (HAL) showed a wide environmental tolerance and was usually found sympatrically with the LD2 or GKS2-217 subcluster. Ecological differentiation of SOL bacteria at the subcluster level was most probably driven by differential adaptation to water chemistry. The distribution of the two vicarious taxa seems to be predominantly controlled by the geological backgrounds of the catchment areas of the habitats.

Switchable vanadium oxide films by a sol-gel process

NASA Astrophysics Data System (ADS)

Partlow, D. P.; Gurkovich, S. R.; Radford, K. C.; Denes, L. J.

1991-07-01

Thin polycrystalline films of VO2 and V2O3 were deposited on a variety of substrates using a sol-gel process. The orientation, microstructure, optical constants, and optical and electrical switching behavior are presented. These films exhibited sharp optical switching behavior even on an amorphous substrate such as fused silica. The method yields reproducible results and is amenable to the coating of large substrates and curved surfaces such as mirrors and lenses.

Effects of sol aging on resistive switching behaviors of HfOx resistive memories

NASA Astrophysics Data System (ADS)

Hsu, Chih-Chieh; Sun, Jhen-Kai; Tsao, Che-Chang; Chen, Yu-Ting

2017-03-01

This work investigates effects of long-term sol-aging time on sol-gel HfOx resistive random access memories (RRAMs). A nontoxic solvent of ethanol is used to replace toxic 2-methoxyethanol, which is usually used in sol-gel processes. The top electrodes are fabricated by pressing indium balls onto the HfOx surface rather than by using conventional sputtering or evaporation processes. The maximum process temperature is limited to be 100 ℃. Therefore, influences of plasma and high temperature on HfOx film can be avoided. Under this circumstance, effects of sol aging time on the HfOx films can be more clearly studied. The current conduction mechanisms in low and high electric regions of the HfOx RRAM are found to be dominated by Ohmic conduction and trap-filled space charge limited conduction (TF-SCLC), respectively. When the sol aging time increases, the resistive switching characteristic of the HfOx layer becomes unstable and the transition voltage from Ohmic conduction to TF-SCLC is also increased. This suggests that an exceedingly long aging time will give a HfOx film with more defect states. The XPS results are consistent with FTIR analysis and they can further explain the unstable HfOx resistive switching characteristic induced by sol aging.

Structural and electrical properties of ferroelectric Na{sub 0.5} (Bi{sub 1-x}Pr{sub x} ){sub 0.5}TiO{sub 3} (x=0.00 and 0.10) ceramics synthesized by Sol-Gel method

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

Shalini, K.; Muneeswaran, M.; Giridharan, N. V., E-mail: giri@nitt.edu

2016-05-23

Ferroelectric Na{sub 0.5}(Bi{sub 1-x}Pr{sub x}){sub 0.5}TiO{sub 3} (x=0.00, 0.10) ceramics have been synthesized through sol-gel method. The phase formation has been confirmed by X-ray diffraction analysis of ceramics annealed at 800°C. The relaxation mechanism is observed from variation of dielectric constant with respect to temperature and frequency. Substitution of Pr reduces vacancies and defects identified from leakage current measurements. Further, the polarization Vs electric field (P-E) measurements have been performed at room temperature.

Overnight Changes Recorded by Phoenix Conductivity Probe

NASA Technical Reports Server (NTRS)

2008-01-01

This graph presents simplified data from overnight measurements by the Thermal and Electrical Conductivity Probe on NASA's Phoenix Mars Lander from noon of the mission's 70th Martian day, or sol, to noon the following sol (Aug. 5 to Aug. 6, 2008).

The graph shows that water disappeared from the atmosphere overnight, at the same time that electrical measurements detected changes consistent with addition of water to the soil.

Water in soil appears to increase overnight, when water in the atmosphere disappears.

The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is by NASA's Jet Propulsion Laboratory, Pasadena, Calif. Spacecraft development is by Lockheed Martin Space Systems, Denver.

Low temperature sintered giant dielectric permittivity CaCu3Ti4O12 sol-gel synthesized nanoparticle capacitors

NASA Astrophysics Data System (ADS)

Puli, Venkata Sreenivas; Adireddy, Shiva; Kothakonda, Manish; Elupula, Ravinder; Chrisey, Douglas B.

This paper reports on synthesis of polycrystalline complex perovskite CaCu3Ti4O12 (as CCTO) ceramic powders prepared by a sol-gel auto combustion method at different sintering temperatures and sintering times, respectively. The effect of sintering time on the structure, morphology, dielectric and electrical properties of CCTO ceramics is investigated. Tuning the electrical properties via different sintering times is demonstrated for ceramic samples. X-ray diffraction (XRD) studies confirm perovskite-like structure at room temperature. Abnormal grain growth is observed for ceramic samples. Giant dielectric permittivity was realized for CCTO ceramics. High dielectric permittivity was attributed to the internal barrier layer capacitance (IBLC) model associated with the Maxwell-Wagner (MW) polarization mechanism.

Rapid change of blob structure in the outer scrape-off layer (SOL)

NASA Astrophysics Data System (ADS)

Cohen, R. H.

2005-10-01

Nonlinear structures (``blobs'') driven by the magnetic field curvature and highly elongated along the field lines may exist in the tokamak SOL.footnotetextS.I. Krasheninnikov. Phys. Lett. A 283, 368 (2001) The contact of the blob end with the divertor plate significantly affects the blob structure and velocity. However, the strong shearing of the flux-tube near the X-point makes impossible direct electrical contact of the blob in the upper SOL and the divertor, so that the sheath boundary condition (BC) has to be replaced by a BC imposed near the X point.footnotetextD. Ryutov, R.H. Cohen. Contr. Pl. Phys 44, 168 (2004) We show that, at larger distances from the separatrix, in the far SOL, the connection between the upper SOL and the divertor plate is re-established, and the sheath BC becomes again relevant. During the blob's outward radial motion, this event is reflected in a sudden change of its length, from the blob extending only to the X point to the blob extending down to the plate. Likewise, a blob initially existing only in the divertor leg becomes suddenly longer, and extends to the whole SOL.

Cellulose-silica/gold nanomaterials for electronic applications.

PubMed

Kim, Gwang-Hoon; Ramesh, Sivalingam; Kim, Joo-Hyung; Jung, Dongsoo; Kim, Heung Soo

2014-10-01

Cellulose and one dimensional nano-material composite has been investigated for various industrial applications due to their optical, mechanical and electrical properties. In present investigation, cellulose/silica and silica-gold hybrid biomaterials were prepared by sol-gel covalent cross-linking process. The tetraethoxysiliane (TEOS) and gold precursors and γ-aminopropyltriethoxysilane (γ-APTES) as coupling agent were used for sol-gel cross-linking process. The chemical and morphological properties of cellulose/silica and cellulose/silica-gold nano-materials via covalent cross-linking hybrids were confirmed by FTIR, XRD, SEM, and TEM analysis. In the sol-gel process, the inorganic particles were dispersed in the cellulose host matrix at the nanometer scale, bonding to the cellulose through the covalent bonds.

SolCalc: A Suite for the Calculation and the Display of Magnetic Fields Generated by Solenoid Systems

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

Lopes, M. L.

2014-07-01

SolCalc is a software suite that computes and displays magnetic fields generated by a three dimensional (3D) solenoid system. Examples of such systems are the Mu2e magnet system and Helical Solenoids for muon cooling systems. SolCalc was originally coded in Matlab, and later upgraded to a compiled version (called MEX) to improve solving speed. Matlab was chosen because its graphical capabilities represent an attractive feature over other computer languages. Solenoid geometries can be created using any text editor or spread sheets and can be displayed dynamically in 3D. Fields are computed from any given list of coordinates. The field distributionmore » on the surfaces of the coils can be displayed as well. SolCalc was benchmarked against a well-known commercial software for speed and accuracy and the results compared favorably.« less

Fabrication of highly conductive graphene/ITO transparent bi-film through CVD and organic additives-free sol-gel techniques.

PubMed

Hemasiri, Bastian Waduge Naveen Harindu; Kim, Jae-Kwan; Lee, Ji-Myon

2017-12-19

Indium tin oxide (ITO) still remains as the main candidate for high-performance optoelectronic devices, but there is a vital requirement in the development of sol-gel based synthesizing techniques with regards to green environment and higher conductivity. Graphene/ITO transparent bi-film was synthesized by a two-step process: 10 wt. % tin-doped ITO thin films were produced by an environmentally friendly aqueous sol-gel spin coating technique with economical salts of In(NO 3 ) 3 .H 2 O and SnCl 4 , without using organic additives, on surface free energy enhanced (from 53.826 to 97.698 mJm -2 ) glass substrate by oxygen plasma treatment, which facilitated void-free continuous ITO film due to high surface wetting. The chemical vapor deposited monolayer graphene was transferred onto the synthesized ITO to enhance its electrical properties and it was capable of reducing sheet resistance over 12% while preserving the bi-film surface smoother. The ITO films contain the In 2 O 3 phase only and exhibit the polycrystalline nature of cubic structure with 14.35 ± 0.5 nm crystallite size. The graphene/ITO bi-film exhibits reproducible optical transparency with 88.66% transmittance at 550 nm wavelength, and electrical conductivity with sheet resistance of 117 Ω/sq which is much lower than that of individual sol-gel derived ITO film.

Material for surface-enhanced Raman spectroscopy, and SER sensors and method for preparing same

NASA Technical Reports Server (NTRS)

Farquharson, Stuart (Inventor); Nelson, Chad (Inventor); Lee, Yuan-Hsiang (Inventor)

2003-01-01

Metal-doped sol-gel materials, suitable for use as sensors for surface-enhanced Raman spectroscopic analysis for trace chemical detection, are produced by effecting gelation and solvent removal of a doped sol-gel under mild temperature conditions. At least in certain instances reaction and drying will desirably be effected in an oxygen-starved environment. The metal of the sol-gel material functions, when irradiated, to produce a plasmon field for interaction with molecules of an analyte in contact therewith, increasing by orders of magnitude Raman photons that are generate by excitation radiation, and the method allows matching of the metal and metal particle size to a wavelength of light (or incident radiation, e.g., laser radiation) to generate surface plasmons. The porosity of the sol-gel material dramatically increases the surface area, and thereby the amount of metal exposed for analyte interaction. The sensors provided may be in the form of glass vials, fiber optics, multi-well micro-sample plates, etc., having surface coatings of the doped sol-gel material, to provide sampling systems for use in a Raman instrument.

Kinetic simulations of scrape-off layer physics in the DIII-D tokamak

DOE PAGES

Churchill, Randy M.; Canik, John M.; Chang, C. S.; ...

2016-12-27

Simulations using the fully kinetic code XGCa were undertaken to explore the impact of kinetic effects on scrape-off layer (SOL) physics in DIII-D H-mode plasmas. XGCa is a total- f, gyrokinetic code which self-consistently calculates the axisymmetric electrostatic potential and plasma dynamics, and includes modules for Monte Carlo neutral transport. Fluid simulations are normally used to simulate the SOL, due to its high collisionality. However, depending on plasma conditions, a number of discrepancies have been observed between experiment and leading SOL fluid codes (e.g. SOLPS), including underestimating outer target temperatures, radial electric field in the SOL, parallel ion SOL flowsmore » at the low field side, and impurity radiation. Many of these discrepancies may be linked to the fluid treatment, and might be resolved by including kinetic effects in SOL simulations. The XGCa simulation of the DIII-D tokamak in a nominally sheath-limited regime show many noteworthy features in the SOL. The density and ion temperature are higher at the low-field side, indicative of ion orbit loss. The SOL ion Mach flows are at experimentally relevant levels ( Mi ~0.5), with similar shapes and poloidal variation as observed in various tokamaks. Surprisingly, the ion Mach flows close to the sheath edge remain subsonic, in contrast to the typical fluid Bohm criterion requiring ion flows to be above sonic at the sheath edge. Related to this are the presence of elevated sheath potentials, eΔΦ/T e ~ 3–4, over most of the SOL, with regions in the near-SOL close to the separatrix having eΔΦ/Te > 4. Finally, these two results at the sheath edge are a consequence of non-Maxwellian features in the ions and electrons there.« less

Chemical sensing of copper phthalocyanine sol-gel glass through organic vapors

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

Ridhi, R.; Gawri, Isha; Abbas, Saeed J.

2015-05-15

The sensitivities of metallophthalocyanine to vapor phase electron donors has gained significance in many areas and disciplines due to their sensing properties and ease of operation. In the present study the interaction mechanism of organic vapors in Copper Phthalocyanine (CuPc) sol-gel glass has been studied. The interaction mechanism is affected by many factors like morphology, electrical or optical properties of film. CuPc sol-gel glass has been synthesized using chemical route sol-gel method. Its structural characterization was conducted using XRD and the amorphous nature of the silicate glass was observed with characteristic α polymorph phase of CuPc at around 6.64° withmore » 13.30Å interplanar spacing. The size of the particle as determined using Debbye Scherre’s formula comes out around 15.5 nm. The presence of α phase of CuPc was confirmed using FTIR with the appearance of crystal parameter marker band at 787 cm-1. Apart from this A2u and Eu symmetry bands of CuPc have also been observed. The UV absorption spectrum of CuPc exhibits absorption peaks owing to π→ π* and n→ π* transitions. A blue shift in the prepared CuPc glass has been observed as compared to the dopant CuPc salt indicating increase of band gap. A split in B (Soret) band and Q band appears as observed with the help of Lorentzian fitting. CuPc sol gel glass has been exposed with chemical vapors of Methanol, Benzene and Bromine individually and the electrical measurements have been carried out. These measurements show the variation in conductivity and the interaction mechanism has been analyzed.« less

Polyethylene glycol assisted growth of Sn-doped ZnO nanorod arrays prepared via sol-gel immersion method

NASA Astrophysics Data System (ADS)

Ismail, A. S.; Mamat, M. H.; Malek, M. F.; Saidi, S. A.; Yusoff, M. M.; Mohamed, R.; Sin, N. D. Md; Suriani, A. B.; Rusop, M.

2018-05-01

Tin-doped zinc oxide (SZO) nanorod films at different concentrations of polyethylene glycol (PEG) were successfully deposited on zinc oxide (ZnO) seeded layer catalyst using sol-gel immersion method. The morphology of the samples were characterized using field emission scanning electron microscopy (FESEM), optical properties using UV-Vis spectrophotometer and electrical properties using I-V measurement system. The current-voltage (I-V) characteristics displayed that 5 wt % sample produced the highest conductivity.

Silver nanowires network encapsulated by low temperature sol-gel ZnO for transparent flexible electrodes with ambient stability

NASA Astrophysics Data System (ADS)

Shin, Wonjung; Cho, Wonki; Baik, Seung Jae

2018-01-01

As a geometrically engineered realization of transparent electrode, Ag nanowires network is promising for its superior characteristics both on electrical conductivity and optical transmittance. However, for a potential commercialization of Ag nanowires network, further investigations on encapsulation materials are necessary to prevent degradation caused by ambient aging. In addition, the temperature range of the coating process for the encapsulation material needs to be low enough to prevent degradation of polymer substrates during the film coating processes, when considering emerging flexible device application of transparent electrodes. We present experimental results showing that low temperature sol-gel ZnO processed under 130 °C is an effective encapsulation material preventing ambient oxidation of Ag nanowires network without degrading electrical, optical, and mechanical properties.

Electrical characterization of γ-Al2O3 thin film parallel plate capacitive sensor for trace moisture detection

NASA Astrophysics Data System (ADS)

Kumar, Lokesh; Kumar, Shailesh; Khan, S. A.; Islam, Tariqul

2012-10-01

A moisture sensor was fabricated based on porous thin film of γ-Al2O3 formed between the parallel gold electrodes. The sensor works on capacitive technique. The sensing film was fabricated by dipcoating of aluminium hydroxide sol solution obtained from the sol-gel method. The porous structure of the film of γ-Al2O3 phase was obtained by sintering the film at 450 °C for 1 h. The electrical parameters of the sensor have been determined by Agilent 4294A impedance analyzer. The sensor so obtained is found to be sensitive in moisture range 100-600 ppmV. The response time of the sensor in ppmV range moisture is very low ~ 24 s and recovery time is ~ 37 s.

Improved two-point model for limiter scrape-off layer

NASA Astrophysics Data System (ADS)

Tokar, M. Z.; Kobayashi, M.; Feng, Y.

2004-10-01

An analytical model for a limiter scrape-off layer (SOL) is proposed, which takes self-consistently into account both conductive and convective contributions to the heat transport in SOL. The particle flows in the SOL main part are determined by considering the recycling of neutrals. The model allows us to interpret the results of numerical simulation by the code EMC3-EIRENE [Y. Feng, F. Sardei, P. Grigull, K. McCormick, J. Kisslinger, D. Reiter, and Y. Igitkhanov, Plasma Phys. Controlled Fusion 44, 611 (2002)] for the edge region of Tokamak Experiment for Technology Oriented Research (TEXTOR) [Proceedings of the 16th IEEE Symposium on Fusion Engineering, 1995 (Institute for Electrical and Electronics Engineers, Piscataway, NJ, 1995), p. 470].

Photo-Definable Self Assembled Maerials

DOEpatents

DOSHI, DHAVAL; [et al

2004-10-26

The present invention provides a mesoporous material comprising at least one region of mesoporous material patterned at a lithographic scale. The present invention also provides a a method for forming a patterned mesoporous material comprising: coating a sol on a substrate to form a film, the sol comprising: a templating molecule, a photoactivator generator, a material capable of being sol-gel processed, water, and a solvent; and exposing the film to light to form a patterned mesoporous material.

Effects of inorganic acids and divalent hydrated metal cations (Mg(2+), Ca(2+), Co(2+), Ni(2+)) on γ-AlOOH sol-gel process.

PubMed

Zhang, Jian; Xia, Yuguo; Zhang, Li; Chen, Dairong; Jiao, Xiuling

2015-11-07

In-depth understanding of the sol-gel process plays an essential role in guiding the preparation of new materials. Herein, the effects of different inorganic acids (HCl, HNO3 and H2SO4) and divalent hydrated metal cations (Mg(2+), Ca(2+), Co(2+), Ni(2+)) on γ-AlOOH sol-gel process were studied based on experiments and density functional theory (DFT) calculations. In these experiments, the sol originating from the γ-AlOOH suspension was formed only with the addition of HCl and HNO3, but not with H2SO4. Furthermore, the DFT calculations showed that the strong adsorption of HSO4(-) on the surface of the γ-AlOOH particles, and the hydrogen in HSO4(-) pointing towards the solvent lead to an unstable configuration of electric double layer (EDL). In the experiment, the gelation time sequence of γ-AlOOH sol obtained by adding metal ions changed when the ionic strength was equal to or greater than 0.198 mol kg(-1). The DFT calculations demonstrated that the adsorption energy of hydrated metal ions on the γ-AlOOH surface can actually make a difference in the sol-gel process.

Anticorrosion Coatings Based on Assemblies of Superhydrophobic Particles Impregnated with Conductive Oil

DTIC Science & Technology

2016-05-13

silver nanowires synthesized in our group using sol-gel techniques...been demonstrated (Figure 12). The electrical resistance of the coatings should further be decreased Figure 14. High aspect ratio silver nanowires ...the coatings is to use a conductive polymer matrix and disperse high aspect ratio silver nanowires into the coating formulations. The electrical

Extending fullwave core ICRF simulation to SOL and antenna regions using FEM solver

NASA Astrophysics Data System (ADS)

Shiraiwa, S.; Wright, J. C.

2016-10-01

A full wave simulation approach to solve a driven RF waves problem including hot core, SOL plasmas and possibly antenna is presented. This approach allows for exploiting advantages of two different way of representing wave field, namely treating spatially dispersive hot conductivity in a spectral solver and handling complicated geometry in SOL/antenna region using an unstructured mesh. Here, we compute a mode set in each region with the RF electric field excitation on the connecting boundary between core and edge regions. A mode corresponding to antenna excitation is also computed. By requiring the continuity of tangential RF electric and magnetic fields, the solution is obtained as unique superposition of these modes. In this work, TORIC core spectral solver is modified to allow for mode excitation, and the edge region of diverted Alcator C-Mod plasma is modeled using COMSOL FEM package. The reconstructed RF field is similar in the core region to TORIC stand-alone simulation. However, it contains higher poloidal modes near the edge and captures a wave bounced and propagating in the poloidal direction near the vacuum-plasma boundary. These features could play an important role when the single power pass absorption is modest. This new capability will enable antenna coupling calculations with a realistic load plasma, including collisional damping in realistic SOL plasma and other loss mechanisms such as RF sheath rectification. USDoE Awards DE-FC02-99ER54512, DE-FC02-01ER54648.

Determination of Insulator-to-Semiconductor Transition in Sol-Gel Oxide Semiconductors Using Derivative Spectroscopy.

PubMed

Lee, Woobin; Choi, Seungbeom; Kim, Kyung Tae; Kang, Jingu; Park, Sung Kyu; Kim, Yong-Hoon

2015-12-23

We report a derivative spectroscopic method for determining insulator-to-semiconductor transition during sol-gel metal-oxide semiconductor formation. When an as-spun sol-gel precursor film is photochemically activated and changes to semiconducting state, the light absorption characteristics of the metal-oxide film is considerable changed particularly in the ultraviolet region. As a result, a peak is generated in the first-order derivatives of light absorption ( A' ) vs. wavelength (λ) plots, and by tracing the peak center shift and peak intensity, transition from insulating-to-semiconducting state of the film can be monitored. The peak generation and peak center shift are described based on photon-energy-dependent absorption coefficient of metal-oxide films. We discuss detailed analysis method for metal-oxide semiconductor films and its application in thin-film transistor fabrication. We believe this derivative spectroscopy based determination can be beneficial for a non-destructive and a rapid monitoring of the insulator-to-semiconductor transition in sol-gel oxide semiconductor formation.

Impact of the impurity seeding for divertor protection on the performance of fusion reactors

NASA Astrophysics Data System (ADS)

Siccinio, Mattia; Fable, Emiliano; Angioni, Clemente; Saarelma, Samuli; Scarabosio, Andrea; Zohm, Hartmut

2017-10-01

A 0D divertor and scrape-off layer (SOL) model has been coupled to the 1.5D core transport code ASTRA. The resulting numerical tool has been employed for various parameter scans in order to identify the most convenient choices for the operation of electricity producing fusion devices with seeded impurities for the divertor protection. In particular, the repercussions of such radiative species on the main plasma through the fuel dilution have been taken into account. The main result we found is that, when the limits on the maximum tolerable divertor heat flux are enforced, the curves at constant electrical power output are closed on themselves in the R-BT plane, i.e. no improvement would descend from a further increase of R or BT once the maximum has been reached. This occurrence appears as an intrinsic physical limit for all devices where a radiative SOL is needed to deal with the power exhaust. Furthermore, the relative importance of the different power loss channels (e.g. hydrogen radiation, charge exchange, perpendicular transport and impurity radiation), through which the power entering the SOL is dissipated before reaching the target plate, is investigated with our model.

Brilliant molecular nanocrystals emerging from sol-gel thin films: towards a new generation of fluorescent biochips.

PubMed

Dubuisson, E; Monnier, V; Sanz-Menez, N; Boury, B; Usson, Y; Pansu, R B; Ibanez, A

2009-08-05

To develop highly sensitive biosensors, we made directly available to biological aqueous solutions organic nanocrystals previously grown in the pores of sol-gel films. Through the controlled dissolution of the sol-gel surface, we obtained emerging nanocrystals that remained strongly anchored to the sol-gel coating for good mechanical stability of the final sensing device. We demonstrated that in the presence of a solution of DNA functionalized with a molecular probe, the nanocrystal fluorescence is strongly quenched by Förster resonance energy transfer thus opening the way towards very sensitive fluorescent biosensors through biomolecules grafted onto fluorescent nanocrystals. Finally, this controlled dissolution, involving weak concentrated NaOH solution, is a generic process that can be used for the thinning of any kind of sol-gel layer.

Phoenix Conductivity Probe after Extraction from Martian Soil on Sol 99

NASA Technical Reports Server (NTRS)

2008-01-01

NASA's Phoenix Mars Lander inserted the four needles of its thermal and conductivity probe into Martian soil during the 98th Martian day, or sol, of the mission and left it in place until Sol 99 (Sept. 4, 2008).

The Surface Stereo Imager on Phoenix took this image on the morning of Sol 99 after the probe was lifted away from the soil. This imaging served as a check of whether soil had stuck to the needles.

The thermal and conductivity probe measures how fast heat and electricity move from one needle to an adjacent one through the soil or air between the needles. Conductivity readings can be indicators about water vapor, water ice and liquid water.

The probe is part of Phoenix's Microscopy, Electrochemistry and Conductivity suite of instruments.

The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is by NASA's Jet Propulsion Laboratory, Pasadena, Calif. Spacecraft development is by Lockheed Martin Space Systems, Denver.

Recovery in skeletal muscle contractile function after prolonged hindlimb immobilization

NASA Technical Reports Server (NTRS)

Fitts, R. H.; Brimmer, C. J.

1985-01-01

The effect of three-month hindlimb immobilization (IM) in rats on contractile properties of slow-twitch soleus (SOL), fast-twitch extensor digitorum longus, and fast-twitch superficial region of the vastus lateralis were measured after 0, 14, 28, 60, and 90 days of recovery on excized, horizontally suspended muscles stimulated electrically to maximal twitch tension. IM caused decreases in muscle-to-body weight ratios for all muscles, with no complete recovery even after 90 days. The contractile properties of the fast-twitch muscles were less affected by IM than those of the slow-twitch SOL. The SOL isometric twitch duration was shortened, due to reduced contraction and half-relaxation time, both of which returned to control levels after 14 days of recovery. The peak tetanic tension, P(O), g/sq cm,, decreased with IM by 46 percent in the SOL, but recovered by the 28th day. The maximum shortening velocity was not altered by IM in any of the muscles. Thus, normal contractile function could recover after prolonged limb IM.

Electrical characterization of ZnO/NiO p-n junction prepared by the sol-gel method

NASA Astrophysics Data System (ADS)

Merih Akyuzlu, A.; Dagdelen, Fethi; Gultek, Ahmet; Hendi, A. A.; Yakuphanoglu, Fahrettin

2017-04-01

ZnO and NiO films were synthesized on fluourine-doped tin oxide (FTO) glass substrate by the sol-gel method. The surface morphology of the films was investigated by atomic force microscopy. The optical band gaps of the ZnO and NiO films were found to be 3.198 and 3.827eV, respectively. A ZnO/NiO p-n junction diode was prepared and electrical charge transport mechanism of the diode was analyzed using thermionic emission and Norde functions. The ideality factor, barrier height and series resistance of the diode were determined to be 6.46, 1.036eV and 39.1 M {Ω} , respectively. The obtained results indicate that ZnO/NiO p-n junction can be used as transparent diode for optic communications.

Ceramic Composite Thin Films

NASA Technical Reports Server (NTRS)

Dikin, Dmitriy A. (Inventor); Nguyen, SonBinh T. (Inventor); Ruoff, Rodney S. (Inventor); Stankovich, Sasha (Inventor)

2013-01-01

A ceramic composite thin film or layer includes individual graphene oxide and/or electrically conductive graphene sheets dispersed in a ceramic (e.g. silica) matrix. The thin film or layer can be electrically conductive film or layer depending the amount of graphene sheets present. The composite films or layers are transparent, chemically inert and compatible with both glass and hydrophilic SiOx/silicon substrates. The composite film or layer can be produced by making a suspension of graphene oxide sheet fragments, introducing a silica-precursor or silica to the suspension to form a sol, depositing the sol on a substrate as thin film or layer, at least partially reducing the graphene oxide sheets to conductive graphene sheets, and thermally consolidating the thin film or layer to form a silica matrix in which the graphene oxide and/or graphene sheets are dispersed.

Enhanced electrical properties in sub-10-nm WO3 nanoflakes prepared via a two-step sol-gel-exfoliation method

PubMed Central

2014-01-01

The morphology and electrical properties of orthorhombic β-WO3 nanoflakes with thickness of ~7 to 9 nm were investigated at the nanoscale with a combination of scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), current sensing force spectroscopy atomic force microscopy (CSFS-AFM, or PeakForce TUNA™), Fourier transform infra-red absorption spectroscopy (FTIR), linear sweep voltammetry (LSV) and Raman spectroscopy techniques. CSFS-AFM analysis established good correlation between the topography of the developed nanostructures and various features of WO3 nanoflakes synthesized via a two-step sol-gel-exfoliation method. It was determined that β-WO3 nanoflakes annealed at 550°C possess distinguished and exceptional thickness-dependent properties in comparison with the bulk, micro and nanostructured WO3 synthesized at alternative temperatures. PMID:25221453

Hybrid Thin Film Organosilica Sol-Gel Coatings To Support Neuronal Growth and Limit Astrocyte Growth.

PubMed

Capeletti, Larissa Brentano; Cardoso, Mateus Borba; Dos Santos, João Henrique Zimnoch; He, Wei

2016-10-07

Thin films of silica prepared by a sol-gel process are becoming a feasible coating option for surface modification of implantable neural sensors without imposing adverse effects on the devices' electrical properties. In order to advance the application of such silica-based coatings in the context of neural interfacing, the characteristics of silica sol-gel are further tailored to gain active control of interactions between cells and the coating materials. By incorporating various readily available organotrialkoxysilanes carrying distinct organic functional groups during the sol-gel process, a library of hybrid organosilica coatings is developed and investigated. In vitro neural cultures using PC12 cells and primary cortical neurons both reveal that, among these different types of hybrid organosilica, the introduction of aminopropyl groups drastically transforms the silica into robust neural permissive substrate, supporting neuron adhesion and neurite outgrowth. Moreover, when this organosilica is cultured with astrocytes, a key type of glial cells responsible for glial scar response toward neural implants, such cell growth promoting effect is not observed. These findings highlight the potential of organo-group-bearing silica sol-gel to function as advanced coating materials to selectively modulate cell response and promote neural integration with implantable sensing devices.

Twitch analysis as an approach to motor unit activation during electrical stimulation.

PubMed

Heyters, M; Carpentier, A; Duchateau, J; Hainaut, K

1994-12-01

The mechanical twitch in response to increasing electrical stimulus intensity, delivered both over the motor point and motor nerve, was recorded in the first dorsal interosseous (FDI) and the adductor pollicis (AP), and only over the motor point in the soleus (Sol), lateral (LG), and medial (MG) gastrocnemius muscles of human subjects. The relationship between intensity of electrical stimulation (ES) and twitch torque showed a positive linear regression in all muscles. In the FDI and AP the relationship was not significantly different when ES was applied at the motor point or over the motor nerve. At small intensities of activation, ES induced larger twitch torques in the MG and LG, which contain a roughly equal proportion of slow and fast motor units (MUs) compared to the Sol, which is composed mainly of slow type fibres. Moreover, the relationship between ES intensity and twitch time-to-peak is best fitted in all muscles by a power curve that shows a greater twitch time-to-peak range in its initial part for muscles containing a larger proportion of fast MUs (LG, MG) than for muscles mainly composed of slow MUs (Sol). In conclusion, these results induced by ES at the motor point and/or over the motor nerve confirm the concept of a reversed sequence of MU activation, as compared to voluntary contractions, and document this viewpoint in muscles of different function and composition. The reversed sequence of MU activation is more clearly evident during motor point ES.

Site selective generation of sol-gel deposits in layered bimetallic macroporous electrode architectures.

PubMed

Lalo, Hélène; Bon-Saint-Côme, Yémima; Plano, Bernard; Etienne, Mathieu; Walcarius, Alain; Kuhn, Alexander

2012-02-07

The elaboration of an original composite bimetallic macroporous electrode containing a site-selective sol-gel deposit is reported. Regular colloidal crystals, obtained by a modified Langmuir-Blodgett approach, are used as templates for the electrogeneration of the desired metals in the form of a well-defined layered bimetallic porous electrode. This porous matrix shows a spatially modulated electroactivity which is subsequently used as a strategy for targeted electrogeneration of a sol-gel deposit, exclusively in one predefined part of the porous electrode.

Computer Language For Optimization Of Design

NASA Technical Reports Server (NTRS)

Scotti, Stephen J.; Lucas, Stephen H.

1991-01-01

SOL is computer language geared to solution of design problems. Includes mathematical modeling and logical capabilities of computer language like FORTRAN; also includes additional power of nonlinear mathematical programming methods at language level. SOL compiler takes SOL-language statements and generates equivalent FORTRAN code and system calls. Provides syntactic and semantic checking for recovery from errors and provides detailed reports containing cross-references to show where each variable used. Implemented on VAX/VMS computer systems. Requires VAX FORTRAN compiler to produce executable program.

Graphene-silica composite thin films as transparent conductors.

PubMed

Watcharotone, Supinda; Dikin, Dmitriy A; Stankovich, Sasha; Piner, Richard; Jung, Inhwa; Dommett, Geoffrey H B; Evmenenko, Guennadi; Wu, Shang-En; Chen, Shu-Fang; Liu, Chuan-Pu; Nguyen, SonBinh T; Ruoff, Rodney S

2007-07-01

Transparent and electrically conductive composite silica films were fabricated on glass and hydrophilic SiOx/silicon substrates by incorporation of individual graphene oxide sheets into silica sols followed by spin-coating, chemical reduction, and thermal curing. The resulting films were characterized by SEM, AFM, TEM, low-angle X-ray reflectivity, XPS, UV-vis spectroscopy, and electrical conductivity measurements. The electrical conductivity of the films compared favorably to those of composite thin films of carbon nanotubes in silica.

Graphene-silica Composite Thin Films as Transparent Conductors

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

Watcharotone,S.; Dikin, D.; Stankovich, S.

2007-01-01

Transparent and electrically conductive composite silica films were fabricated on glass and hydrophilic SiO{sub x}/silicon substrates by incorporation of individual graphene oxide sheets into silica sols followed by spin-coating, chemical reduction, and thermal curing. The resulting films were characterized by SEM, AFM, TEM, low-angle X-ray reflectivity, XPS, UV-vis spectroscopy, and electrical conductivity measurements. The electrical conductivity of the films compared favorably to those of composite thin films of carbon nanotubes in silica.

Large-Scale Precise Printing of Ultrathin Sol-Gel Oxide Dielectrics for Directly Patterned Solution-Processed Metal Oxide Transistor Arrays.

PubMed

Lee, Won-June; Park, Won-Tae; Park, Sungjun; Sung, Sujin; Noh, Yong-Young; Yoon, Myung-Han

2015-09-09

Ultrathin and dense metal oxide gate di-electric layers are reported by a simple printing of AlOx and HfOx sol-gel precursors. Large-area printed indium gallium zinc oxide (IGZO) thin-film transistor arrays, which exhibit mobilities >5 cm(2) V(-1) s(-1) and gate leakage current of 10(-9) A cm(-2) at a very low operation voltage of 2 V, are demonstrated by continuous simple bar-coated processes. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Synthesis and Conductometric Property of Sol-Gel-Derived ZnO/PVP Nano Hybrid Films

NASA Astrophysics Data System (ADS)

Ilegbusi, Olusegun J.; Trakhtenberg, Leonid

2013-03-01

ZnO nanoparticles immobilized in polyvinylpyrrolidone (PVP) were prepared using sol-gel dip-coating technique with varying Zn2+/PVP ratios. The films were characterized using atomic force microscopy, x-ray photoelectron spectroscopy, and Fourier transform infrared spectroscopy for chemical analysis. The size and concentration of ZnO particles decreased as the Zn/PVP ratio decreased. Under low Zn2+/PVP molar ratios, ZnO particles were clearly well separated and capped in the PVP polymer matrix. Electrical resistivity of 108 Ω cm was achieved under these deposition conditions.

Hybrid organic-inorganic sol-gel materials and components for integrated optoelectronics

NASA Astrophysics Data System (ADS)

Lu, Dong

On the technical platform of hybrid organic-inorganic sol-gel, the integrated optoelectronics in the forms of heterogeneous integration between the hybrid sol-gel waveguide and the high refractive index semiconductors and the nonlinear functional doping of disperse red chromophore into hybrid sol-gel is developed. The structure of hybrid sol-gel waveguide on high index semiconductor substrate is designed with BPM-CAD software. A hybrid sol-gel based on MAPTMS and TEOS suitable for lower cladding for the waveguide is developed. The multi-layer hybrid sol-gel waveguide with good mode confinement and low polarization dependence is fabricated on Si and InP. As proof of concept, a 1 x 12 beam splitter based on multimode interference is fabricated on silicon substrate. The device shows excess loss below 0.65 dB and imbalance below 0.28 dB for both TE and TM polarization. A nonlinear active hybrid sol-gel doped with disperse red 13 has been developed by simple co-solvent method. It permits high loading concentration and has low optical loss at 1550 nm. The second-order nonlinear property of the active sol-gel is induced with corona poling and studied with second harmonic generation. A 3-fold of enhancement in the poling efficiency is achieved by blue light assisted corona poling. The chromophore alignment stability is improved by reducing the free volume of the formed inorganic network from the sol-gel condensation reaction. An active sol-gel channel waveguide has been fabricated using active and passive hybrid sol-gel materials by only photopatterning and spin-coating. An amplitude modulator based on the active sol-gel containing 30 wt.% of DR13 shows an electro-optic coefficient of 14 pm/V at 1550 nm and stable operation within the observation time of 24 days.

Ionogel Electrolytes through Sol-Gel Processing

NASA Astrophysics Data System (ADS)

Horowitz, Ariel I.

Electrical energy needs have intensified due to the ubiquity of personal electronics, the decarbonization of energy services through electrification, and the use of intermittent renewable energy sources. Despite developments in mechanical and thermal methods, electrochemical technologies are the most convenient and effective means of storing electrical energy. These technologies include both electrochemical cells, commonly called batteries, and electrochemical double-layer capacitors, or "supercapacitors", which store energy electrostatically. Both device types require an ion-conducting electrolyte. Current devices use solutions of complex salts in organic solvents, leading to both toxicity and flammability concerns. These drawbacks can be avoided by replacing conventional electrolytes with room-temperature molten salts, known as ionic liquids (ILs). ILs are non-volatile, non-flammable, and offer high conductivity and good electrochemical stability. Device mass can be reduced by combining ILs with a solid scaffold material to form an "ionogel," further improving performance metrics. In this work, sol-gel chemistry is explored as a means of forming ionogel electrolytes. Sol-gel chemistry is a solution-based, industrially-relevant, well-studied technique by which solids such as silica can be formed in situ. Previous works used a simple acid-catalyzed sol-gel reaction to create brittle, glassy ionogels. Here, both the range of products that can be accomplished through sol-gel processing and the understanding of interactions between ILs and the sol-gel reaction network are greatly expanded. This work introduces novel ionogel materials, including soft and compliant silica-supported ionogels and PDMS-supported ionogels. The impacts of the reactive formulation, IL identity, and casting time are detailed. It is demonstrated that variations in formulation can lead to rapid gelation and open pore structures in the silica scaffold or slow gelation and more dense silica morphologies. The IL identity is shown to have an impact on the apparent strength of the acid catalyst, leading to significant shifts in gelation time. Delayed casting is proven to be an optimal technique for avoiding pore blockage when combining ionogels with high surface area electrodes for supercapacitor applications. Finally, a simple recycling process is proposed, establishing that ILs can be easily reclaimed from silica-supported ionogels and reused, thereby validating the reputation of ILs as "green" materials.

Metal-oxide-based energetic materials and synthesis thereof

DOEpatents

Tillotson, Thomas M. , Simpson; Randall, L [Livermore, CA; Hrubesh, Lawrence W [Pleasanton, CA

2006-01-17

A method of preparing energetic metal-oxide-based energetic materials using sol-gel chemistry has been invented. The wet chemical sol-gel processing provides an improvement in both safety and performance. Essentially, a metal-oxide oxidizer skeletal structure is prepared from hydrolyzable metals (metal salts or metal alkoxides) with fuel added to the sol prior to gelation or synthesized within the porosity metal-oxide gel matrix. With metal salt precursors a proton scavenger is used to destabilize the sol and induce gelation. With metal alkoxide precursors standard well-known sol-gel hydrolysis and condensation reactions are used. Drying is done by standard sol-gel practices, either by a slow evaporation of the liquid residing within the pores to produce a high density solid nanocomposite, or by supercritical extraction to produce a lower density, high porous nanocomposite. Other ingredients may be added to this basic nanostructure to change physical and chemical properties, which include organic constituents for binders or gas generators during reactions, burn rate modifiers, or spectral emitters.

Progress towards modeling tokamak boundary plasma turbulence and understanding its role in setting divertor heat flux widths

NASA Astrophysics Data System (ADS)

Chen, Bin

2017-10-01

QCMs (quasi-coherent modes) are well characterized in the edge of Alcator C-Mod, when operating in the Enhanced Dα (EDA) H-mode, a promising alternative regime for ELM (edge localized modes) suppressed operation. To improve the understanding of the physics behind the QCMs, three typical C-Mod EDA H-Mode discharges are simulated by BOUT + + using a six-field two-fluid model (based on the Braginskii equations). The simulated characteristics of the frequency versus wave number spectra of the modes is in reasonable agreement with phase contrast imaging data. The key simulation results are: 1) Linear spectrum analysis and the nonlinear phase relationship indicate the dominance of resistive-ballooning modes and drift-Alfven wave instabilities; 2) QCMs originate inside the separatrix; (3) magnetic flutter causes the mode spreading into the SOL; 4) the boundary electric field Er changes the turbulent characteristics of the QCMs and controls edge transport and the divertor heat flux width; 5) the magnitude of the divertor heat flux depends on the physics models, such as sources and sinks, sheath boundary conditions, and parallel heat flux limiting coefficient. The BOUT + + simulations have also been performed for inter-ELM periods of DIII-D and EAST discharges, and similar quasi-coherent modes have been found. The parallel electron heat fluxes projected onto the target from these BOUT + + simulations follow the experimental heat flux width scaling, in particular the inverse dependence of the width on the poloidal magnetic field with an outlier. Further turbulence statistics analysis shows that the blobs are generated near the pedestal peak gradient region inside the separatrix and contribute to the transport of the particle and heat in the SOL region. To understand the Goldston heuristic drift-based model, results will also be presented from self-consistent transport simulations with the electric and magnetic drifts in BOUT + + and with the sheath potential included in the SOL. Work supported by LLNL under Contract DE-AC52-07NA27344. This work was also supported by US DOE Grant DE-FC02-99ER54512, using Alcator C-Mod, a DOE Office of Science User Facility, and under the auspices of the CSC (No. 201506340019).

Myostatin dysfunction impairs force generation in extensor digitorum longus muscle and increases exercise-induced protein efflux from extensor digitorum longus and soleus muscles.

PubMed

Baltusnikas, Juozas; Kilikevicius, Audrius; Venckunas, Tomas; Fokin, Andrej; Bünger, Lutz; Lionikas, Arimantas; Ratkevicius, Aivaras

2015-08-01

Myostatin dysfunction promotes muscle hypertrophy, which can complicate assessment of muscle properties. We examined force generating capacity and creatine kinase (CK) efflux from skeletal muscles of young mice before they reach adult body and muscle size. Isolated soleus (SOL) and extensor digitorum longus (EDL) muscles of Berlin high (BEH) mice with dysfunctional myostatin, i.e., homozygous for inactivating myostatin mutation, and with a wild-type myostatin (BEH+/+) were studied. The muscles of BEH mice showed faster (P < 0.01) twitch and tetanus contraction times compared with BEH+/+ mice, but only EDL displayed lower (P < 0.05) specific force. SOL and EDL of age-matched but not younger BEH mice showed greater exercise-induced CK efflux compared with BEH+/+ mice. In summary, myostatin dysfunction leads to impairment in muscle force generating capacity in EDL and increases susceptibility of SOL and EDL to protein loss after exercise.

3D Printed PEG-Based Hybrid Nanocomposites Obtained by Sol-Gel Technique.

PubMed

Chiappone, Annalisa; Fantino, Erika; Roppolo, Ignazio; Lorusso, Massimo; Manfredi, Diego; Fino, Paolo; Pirri, Candido Fabrizio; Calignano, Flaviana

2016-03-02

In this work, three-dimensional (3D) structured hybrid materials were fabricated combining 3D printing technology with in situ generation of inorganic nanoparticles by sol-gel technique. Those materials, consisting of silica nanodomains covalently interconnected with organic polymers, were 3D printed in complex multilayered architectures, incorporating liquid silica precursors into a photocurable oligomer in the presence of suitable photoinitiators and exposing them to a digital light system. A post sol-gel treatment in acidic vapors allowed the in situ generation of the inorganic phase in a dedicated step. This method allows to build hybrid structures operating with a full liquid formulation without meeting the drawbacks of incorporating inorganic powders into 3D printable formulations. The influence of the generated silica nanoparticle on the printed objects was deeply investigated at macro- and nanoscale; the resulting light hybrid structures show improved mechanical properties and, thus, have a huge potential for applications in a variety of advanced technologies.

Low-temperature sintering behavior of nanocrystalline indium tin oxide prepared from polymer-containing sols

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

Koroesi, Laszlo, E-mail: l.korosi@chem.u-szeged.hu; Papp, Szilvia; Oszko, Albert

2012-04-15

Highlights: Black-Right-Pointing-Pointer The synthesis of ITO powders and thin films from PVP-containing sols is presented. Black-Right-Pointing-Pointer The nano- and microstructures of ITO are more compact when PVP is used. Black-Right-Pointing-Pointer PVP acts both as a steric stabilizer of the sol and as a pre-sintering agent. Black-Right-Pointing-Pointer The PVP-induced enhanced sintering results in ITO with lower electrical resistance. Black-Right-Pointing-Pointer The surface composition of the ITO films is independent of the initial PVP content. -- Abstract: Indium tin hydroxide (ITH) xerogel powders and thin films with different polyvinylpyrrolidone (PVP) contents (0-22%, w/w) were prepared by a classical sol-gel method. To obtain nanocrystallinemore » indium tin oxide (ITO), the ITH xerogels were calcined at 550 Degree-Sign C. The effect of the initial polymer content on the structure of the ITO powders was studied by means of N{sub 2}-sorption measurements, small-angle X-ray scattering (SAXS), transmission and scanning electron microscopy. The N{sub 2}-sorption measurements revealed that the ITO powders obtained contained micropores and both their porosity and specific surface area decreased with increasing PVP content of the ITH xerogels. The SAXS measurements confirmed the enhanced sintering of the particles in the presence of PVP. The calculated mass fractal dimensions of the ITO powders increased significantly, indicating a significant compaction in structure. The pre-sintered structure could be achieved at relatively low temperature, which induced a significant decreasing (three orders of magnitude) in the electrical resistance of the ITO films.« less

Social values for ecosystem services (SolVES): A GIS application for assessing, mapping, and quantifying the social values of ecosystem services-Documentation and user manual, version 1.0

USGS Publications Warehouse

Sherrouse, Benson C.; Riegle, Jodi L.; Semmens, Darius J.

2010-01-01

In response to the need for incorporating quantified and spatially explicit measures of social values into ecosystem services assessments, the Rocky Mountain Geographic Science Center, in collaboration with Colorado State University, has developed a geographic information system application, Social Values for Ecosystem Services (SolVES). SolVES can be used to assess, map, and quantify the perceived social values of ecosystem services. SolVES derives a quantitative social values metric, the Value Index, from a combination of spatial and nonspatial responses to public attitude and preference surveys. SolVES also generates landscape metrics, such as average elevation and distance to water, calculated from spatial data layers describing the underlying physical environment. Using kernel density calculations and zonal statistics, SolVES derives and maps the 10-point Value Index and reports landscape metrics associated with each index value for social value types such as aesthetics, biodiversity, and recreation. This can be repeated for various survey subgroups as distinguished by their attitudes and preferences regarding public uses of the forests such as motorized recreation and logging for fuels reduction. The Value Index provides a basis of comparison within and among survey subgroups to consider the effect of social contexts on the valuation of ecosystem services. SolVES includes regression coefficients linking the predicted value (the Value Index) to landscape metrics. These coefficients are used to generate predicted social value maps using value transfer techniques for areas where primary survey data are not available. SolVES was developed, and will continue to be enhanced through future versions, as a public domain tool to enable decision makers and researchers to map the social values of ecosystem services and to facilitate discussions among diverse stakeholders regarding tradeoffs between different ecosystem services in a variety of physical and social contexts.

Effect of Sn doping on structural, mechanical, optical and electrical properties of ZnO nanoarrays prepared by sol-gel and hydrothermal process

NASA Astrophysics Data System (ADS)

Agarwal, Manish Baboo; Sharma, Akash; Malaidurai, M.; Thangavel, R.

2018-05-01

Undoped and Sn doped Zinc oxide nanorods were prepared by two step process: initially growth of seed layers by sol-gel spin coating technique and then zinc oxide nanorods by hydrothermal process using the precursors zinc nitrate hexahydrate, hexamine and tin chloride. The effects on the electrical, optical, mechanical and structural properties for various Sn concentrations were studied. The crystalline phase determination from X-ray diffraction (XRD) confirms that Sn doped ZnO nanorods have hexagonal wurtzite structure. The variations of stress and strain with different doping concentration of Sn in ZnO nanorods were studied. The doping effect on electrical properties and optical bandgap is estimated by current voltage characteristics and absorbance spectra respectively. The surface morphology was studied with field emission scanning electron microscope (FESEM), which shows that the formation of hexagonal nanorods arrays with increasing Sn concentration. The calculated value of Young's modulus of elasticity (Y) for all the samples remains same. These results can be used in optoelectronic devices.

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

Yao, Manwen, E-mail: yaomw@tongji.edu.cn; Peng, Yong; Xiao, Ruihua

SrTiO{sub 3}/nano Al{sub 2}O{sub 3} inorganic nanocomposites were prepared by using a conventional sol-gel spin coating process. For comparison, SrTiO{sub 3} films doped by equivalent amount of sol-Al{sub 2}O{sub 3} have also been investigated. Aluminum deposited by using vacuum evaporation was used as the top electrode. The nanocomposites exhibited a significantly enhanced dielectric strength of 506.9 MV/m, which was increased by 97.4% as compared with the SrTiO{sub 3} films doped with sol-Al{sub 2}O{sub 3}. The leakage current maintained of the same order of microampere until the ultimate breakdown of the nanocomposites. The excellent electrical performances are ascribed to the anodicmore » oxidation reaction in origin, which can repair the internal and/or surface defects of the films.« less

Changes of contractile responses due to simulated weightlessness in rat soleus muscle

NASA Astrophysics Data System (ADS)

Elkhammari, A.; Noireaud, J.; Léoty, C.

1994-08-01

Some contractile and electrophysiological properties of muscle fibers isolated from the slow-twitch soleus (SOL) and fast-twitch extensor digitorum longus (EDL) muscles of rats were compared with those measured in SOL muscles from suspended rats. In suspendede SOL (21 days of tail-suspension) membrane potential (Em), intracellular sodium activity (aiNa) and the slope of the relationship between Em and log [K]o were typical of fast-twitch muscles. The relation between the maximal amplitude of K-contractures vs Em was steeper for control SOL than for EDL and suspended SOL muscles. After suspension, in SOL muscles the contractile threshold and the inactivation curves for K-contractures were shifted to more positive Em. Repriming of K-contractures was unaffected by suspencion. The exposure of isolated fibers to perchlorate (ClO4-)-containing (6-40 mM) solutions resulted ina similar concentration-dependent shift to more negative Em of activation curves for EDL and suspended SOL muscles. On exposure to a Na-free TEA solution, SOL from control and suspended rats, in contrast to EDL muscles, generated slow contractile responses. Suspended SOL showed a reduced sensitivity to the contracture-producing effect of caffeine compared to control muscles. These results suggested that the modification observed due to suspension could be encounted by changes in the characteristics of muscle fibers from slow to fast-twitch type.

Microstructure and transport properties of sol-gel derived highly (100)-oriented lanthanum nickel oxide thin films on SiO 2 /Si substrate

NASA Astrophysics Data System (ADS)

Zhu, M. W.; Wang, Z. J.; Chen, Y. N.; Zhang, Z. D.

2011-12-01

In the present work, lanthanum nickel oxide (LNO) thin films were prepared by the sol-gel method and different thermal treatments were adopted by adjusting the preheating treatment. The microstructure, crystal orientation, chemical composition and electrical properties of LNO films were analyzed to elucidate the relationship between the microstructure and the transport properties of the films. The results show that equiaxed grains predominate the microstructure of the films with pyrolysis step. Without the pyrolysis step, columnar grains are formed in the films, accompanied with an improvement in crystallinity and strengthening of the (100)-orientation. Furthermore, the metal-insulator transition temperature decreases for the films without the pyrolysis step. The effect of film microstructure on its electrical properties was discussed in terms of the existence of internal stress and the improved crystallinity.

CROSS-DISCIPLINARY PHYSICS AND RELATED AREAS OF SCIENCE AND TECHNOLOGY: Effect of Annealing Conditions on Properties of Sol-Gel Derived Al-Doped ZnO Thin Films

NASA Astrophysics Data System (ADS)

Gao, Mei-Zhen; Zhang, Feng; Liu, Jing; Sun, Hui-Na

2009-08-01

Transparent conductive Al-doped ZnO (AZO) thin films are prepared on normal glass substrates by the sol-gel spin coating method. The effects of drying conditions, annealing temperature and cooling rate on the structural, electrical and optical properties of AZO films are investigated by x-ray diffraction, scanning electron microscopy, the four-point probe method and UV-VIS spectrophotometry, respectively. The deposited films show a hexagonal wurtzite structure and high preferential c-axis orientation. As the drying temperature increases from 100°C to 300°C the resistivity of AZO films decreases dramatically. In contrast to the annealed films cooled in a furnace and in air, the resistivity of the annealed film which is cooled at -15°C is greatly reduced. Increasing the cooling rate dramatically increases the electrical conductivity of AZO films.

Sol-gel chemistry-based Ucon-coated columns for capillary electrophoresis.

PubMed

Hayes, J D; Malik, A

1997-07-18

A sol-gel chemistry-based novel approach for the preparation of a Ucon-coated fused-silica capillary column in capillary electrophoresis is presented. In this approach the sol-gel process is carried out inside 25 microm I.D. fused-silica capillaries. The sol solution contained appropriate quantities of an alkoxide-based sol-gel precursor, a polymeric coating material (Ucon), a crosslinking reagent, a surface derivatizing reagent, controlled amounts of water and a catalyst dissolved in a suitable solvent system. The coating procedure involves filling a capillary with the sol solution and allowing the sol-gel process to proceed for an optimum period. Hydrolysis of the alkoxide precursor and polycondensation of the hydrolyzed products with the surface silanol groups and the hydroxy-terminated Ucon molecules lead to the formation of a surface-bonded sol-gel coating on the inner walls of the capillary. The thickness of the coated film can be controlled by varying the reaction time, coating solution composition and experimental conditions. Commercial availability of high purity sol-gel precursors (e.g., TEOS 99.999%), the ease of coating, run-to-run and column-to-column reproducibility, and long column lifetimes make sol-gel coating chemistry very much suitable for being applied in analytical microseparations column technology. Test samples of basic proteins and nucleotides were used to evaluate the column performance. These results show that the sol-gel coating scheme has allowed for the generation of bio-compatible surfaces characterized by high separation efficiencies in CE. For different types of solutes, the sol-gel coated Ucon column consistently provided migration time R.S.D. values of the order of 0.5%.

Fabrication and characterization of sol-gel based nanoparticles for drug delivery

NASA Astrophysics Data System (ADS)

Yadav, Reeta

Nanogels are cross linked polymeric sol-gel based nanoparticles that offer an interior network for incorporation and protection of biomolecules, exhibiting unique advantages for polymer based delivery systems. We have successfully synthesized stable sol-gel nanoparticles by means of [a] silicification reactions using cationic peptides like polylysine as gelating agents, and [b] lyophilization of sol-gels. Macromolecules such as Hemoglobin and Glucose Oxidase and small molecules such as Sodium Nitroprusside (SNP) and antibiotics were encapsulated within the nanogels. We have used transmission electron microscopy, dynamic light scattering, zeta potential analysis, and spectroscopy to perform a physicochemical characterization of the nanogels resulting from the two approaches. Our studies have indicated that the nanogel encapsulated proteins and small molecules remain intact, stable and functional. A Hydrogen Peroxide (H2O2) and Nitric Oxide (NO) generating drug carrier was synthesized using these nanogels and the effect of generation of H2O2 from Glucose Oxidase encapsulated nanogels and NO from SNP encapsulated nanogels was tested on E.coli. The results show that the nanoparticles exert antimicrobial activity against E.Coli, in addition NO generating nanogels potentiated H2O2 generating nanogels induced killing. These data suggest that these NO and H2O2 releasing nanogels have the potential to serve as a novel class of antimicrobials for the treatment of multidrug resistant bacteria. The unique properties of these protein/drug incorporated nanogels raise the prospect of fine tailoring to specific applications such as drug delivery and bio imaging.

Modified Au nanoparticles-imprinted sol-gel, multiwall carbon nanotubes pencil graphite electrode used as a sensor for ranitidine determination.

PubMed

Rezaei, B; Lotfi-Forushani, H; Ensafi, A A

2014-04-01

A new, simple, and disposable molecularly imprinted electrochemical sensor for the determination of ranitidine was developed on pencil graphite electrode (PGE) via cyclic voltammetry (CV). The PGEs were coated with MWCNTs containing the carboxylic functional group (f-MWCNTs), imprinted with sol-gel and Au nanoparticle (AuNPs) layers (AuNP/MIP-sol-gel/f-MWCNT/PGE), respectively, to enhance the electrode's electrical transmission and sensitivity. The thin film of molecularly imprinted sol-gel polymers with specific binding sites for ranitidine was cast on modified PGE by electrochemical deposition. The AuNP/MIP-sol-gel/f-MWCNT/PGE thus developed was characterized by electrochemical impedance spectroscopy (EIS) and CV. The interaction between the imprinted sensor and the target molecule was also observed on the electrode by measuring the current response of 5.0mMK3[Fe(CN)6] solution as an electrochemical probe. The pick currents of ranitidine increased linearly with concentration in the ranges of 0.05 to 2.0μM, with a detection limit of (S/N=3) 0.02μM. Finally, the modified electrode was successfully employed to determine ranitidine in human urine samples. Copyright © 2014 Elsevier B.V. All rights reserved.

Development of a direct three-dimensional biomicrofabrication concept based on electrospraying a custom made siloxane sol.

PubMed

Sullivan, Alice C; Jayasinghe, Suwan N

2007-07-19

We demonstrate here the discovery of a unique and direct three-dimensional biomicrofabrication concept possessing the ability to revolutionize the jet-based fabrication arena. Previous work carried out on similar jet-based approaches have been successful in fabricating only vertical wallpillar-structures by the controlled deposition of stacked droplets. However, these advanced jet-techniques have not been able to directly fabricate self-supporting archeslinks (without molds or reaction methods) between adjacent structures (walls or pillars). Our work reported here gives birth to a unique type of jet determined by high intensity electric fields, which is derived from a specially formulated siloxane sol. The sol studied here has been chosen for its attractive properties (such as an excellent cross-linking nature as well as the ability to polymerize via polycondensation on deposition to its biocompatability), which promotes direct forming of biostructures with nanometer (<50 nm) sized droplets in three dimensions. We foresee that this direct three-dimensional biomicrofabrication jet technique coupled with a variety of formulated sols having focused and enhanced functionality will be explored throughout the physical and life sciences.

Resistive switching memory devices composed of binary transition metal oxides using sol-gel chemistry.

PubMed

Lee, Chanwoo; Kim, Inpyo; Choi, Wonsup; Shin, Hyunjung; Cho, Jinhan

2009-04-21

We describe a novel and versatile approach for preparing resistive switching memory devices based on binary transition metal oxides (TMOs). Titanium isopropoxide (TIPP) was spin-coated onto platinum (Pt)-coated silicon substrates using a sol-gel process. The sol-gel-derived layer was converted into a TiO2 film by thermal annealing. A top electrode (Ag electrode) was then coated onto the TiO2 films to complete device fabrication. When an external bias was applied to the devices, a switching phenomenon independent of the voltage polarity (i.e., unipolar switching) was observed at low operating voltages (about 0.6 VRESET and 1.4 VSET). In addition, it was confirmed that the electrical properties (i.e., retention time, cycling test and switching speed) of the sol-gel-derived devices were comparable to those of vacuum deposited devices. This approach can be extended to a variety of binary TMOs such as niobium oxides. The reported approach offers new opportunities for preparing the binary TMO-based resistive switching memory devices allowing a facile solution processing.

ZnO-based transparent conductive thin films via sonicated-assisted sol-gel technique

NASA Astrophysics Data System (ADS)

Malek, M. F.; Mamat, M. H.; Ismail, A. S.; Yusoff, M. M.; Mohamed, R.; Rusop, M.

2018-05-01

We report on the growth of Al-doped ZnO (AZO) thin films onto Corning 7740 glass substrates via sonicated-assisted sol-gel technique. The influence of Al dopant on crystallisation behavior, optical and electrical properties of AZO films has been systematically investigated. All films are polycrystalline with a hexagonal wurtzite structure with a preferential orientation according to the direction <002>. All films exhibit a transmittance above than 80-90 % along the visible range up to 800 nm and a sharp absorption onset below 400 nm corresponding to the fundamental absorption edge of ZnO.

Studies of Carbon Nanotubes

NASA Technical Reports Server (NTRS)

Caneba, Gerard T.

2005-01-01

The fellowship experience for this summer for 2004 pertains to carbon nanotube coatings for various space-related applications. They involve the following projects: (a) EMI protection films from HiPco-polymers, and (b) Thermal protection nanosilica materials. EMI protection films are targeted to be eventually applied onto casings of laptop computers. These coatings are composites of electrically-conductive SWNTs and compatible polymers. The substrate polymer will be polycarbonate, since computer housings are typically made of carbon composites of this type of polymer. A new experimental copolymer was used last year to generate electrically-conductive and thermal films with HiPco at 50/50 wt/wt composition. This will be one of the possible formulations. Reference films will be base polycarbonate and neat HiPco onto polycarbonate films. Other coating materials that will be tried will be based on HiPco composites with commercial enamels (polyurethane, acrylic, polyester), which could be compatible with the polycarbonate substrate. Nanosilica fibers are planned for possible use as thermal protection tiles on the shuttle orbiter. Right now, microscale silica is used. Going to the nanoscale will increase the surface-volume-per-unit-area of radiative heat dissipation. Nanoscale carbon fibers/nanotubes can be used as templates for the generation of nanosilica. A sol-gel operation is employed for this purpose.

Synthesis and Properties of Carbon Nanotube-Grafted Silica Nanoarchitecture-Reinforced Poly(Lactic Acid)

PubMed Central

Hsu, Yao-Wen; Wu, Chia-Ching; Wu, Song-Mao

2017-01-01

A novel nanoarchitecture-reinforced poly(lactic acid) (PLA) nanocomposite was prepared using multi-walled carbon nanotube (MWCNT)-grafted silica nanohybrids as reinforcements. MWCNT-grafted silica nanohybrids were synthesized by the generation of silica nanoparticles on the MWCNT surface through the sol-gel technique. This synthetic method involves organo-modified MWCNTs that are dispersed in tetrahydrofuran, which incorporates tetraethoxysilane that undergoes an ultrasonic sol-gel process. Gelation yielded highly dispersed silica on the organo-modified MWCNTs. The structure and properties of the nanohybrids were established using 29Si nuclear magnetic resonance, Raman spectroscopy, wide-angle X-ray diffraction, thermogravimetric analysis, and transmission electron microscopy. The resulting MWCNT nanoarchitectures were covalently assembled into silica nanoparticles, which exhibited specific and controllable morphologies and were used to reinforce biodegradable PLA. The tensile strength and the heat deflection temperature (HDT) of the PLA/MWCNT-grafted silica nanocomposites increased when the MWCNT-grafted silica was applied to the PLA matrix; by contrast, the surface resistivity of the PLA/MWCNT-grafted silica nanocomposites appeared to decline as the amount of MWCNT-grafted silica in the PLA matrix increased. Overall, the reinforcement of PLA using MWCNT-grafted silica nanoarchitectures was efficient and improved its mechanical properties, heat resistance, and electrical resistivity. PMID:28773187

SolTrace FAQs | Concentrating Solar Power | NREL

Science.gov Websites

that should be noted: when using a cubic spline file to describe a surface, if that file contains a help for script functions? A: Yes, when typing a script function within the scripting window, as you results. When the limit is reached, SolTrace generates the following error message (Windows version; Mac

Fast and efficient proteolysis by reusable pepsin-encapsulated magnetic sol-gel material for mass spectrometry-based proteomics applications.

PubMed

Kayili, H Mehmet; Salih, Bekir

2016-08-01

Hydrophobic silicon-based material having magnetic properties was fairly synthesized by a classical sol-gel approach. Pepsin enzyme was encapsulated in the sol-gel material and the enzyme activity was evaluated in consequence of the digestion of some common proteins such as α- and β-casein, cytochrome c, myoglobin, and bovine serum albumin (BSA) both in a single protein batch and in the protein mixture. The optimum digestion time of the studied proteins using pepsin-encapsulated magnetic sol-gel material was found to be 20min. To produce the magnetic sol-gel material for convenient and easy proteomics applications, Fe3O4 was doped inside sol-gel material during the gelation step. It was observed that the activity of encapsulated pepsin was not affected by the amount of Fe3O4. Poly(ethylene glycol) was also inserted in sol-gel bulk to obtain suitable roughness and increase the hydrophilicity of the material surface to let protein molecules reach to the sol-gel material easily. The digestion of the protein mixture and non-fat bovine milk was performed with the pepsin-encapsulated magnetic sol-gel material and the digested solutions were analyzed using SDS-PAGE, MALDI-TOF-MS and LC-MS/MS for the protein identification. Reusability of the pepsin-encapsulated sol-gel material was examined and it was determined that they could be used at least 20 times. Finally, IgG digestions with a fast incubation time period were carried out using pepsin-encapsulated sol-gel material for generation of (Fab)2 product to evaluate the kinetic performance of the material. Copyright © 2016 Elsevier B.V. All rights reserved.

Dual controlled release, in situ gelling periodontal sol of metronidazole benzoate and serratiopeptidase: statistical optimization and mechanistic evaluation.

PubMed

Kumari, Neeraj; Pathak, Kamla

2012-01-01

In situ gelling syringeable periodontal sol capable of dual controlled delivery of metronidazole benzoate and serratiopeptidase was designed based on 2(3) factorial design with drug, poloxamer 407 and aerosil as independent variables and sol gel transition characteristics, %CDR(48h) and palatability as responses. The sols had agreeable taste, were mucoadhesive, syringeable and inverted into gels at periodontal cavity temperature. F8 with optimal drug release was identified as the best formulation. The dispersion characteristics of poloxamer significantly affected the pharmacotechnical properties of the in situ gelling systems. Extra design checkpoint generated using Design Expert software 8.02 (Stat-Ease, USA) validated the experimental design. Thus a thermoreversible, in situ gelling and syringeable periodontal sol with acceptable taste characteristics that offered controlled release of metronidazole benzoate and serratiopeptidase was developed for application into the periodontal pocket. The developed optimized sol was satisfactory in terms of taste, syringeability, palatability and incorporation of serratiopeptidase as anti-inflammatory agent, has the potential of developing a therapeutically efficacious system for treatment of periodontal inflammatory anaerobic infections.

Spirit Near 'Stapledon' on Sol 1802 (Stereo)

NASA Technical Reports Server (NTRS)

2009-01-01

[figure removed for brevity, see original site] Left-eye view of a color stereo pair for PIA11781 [figure removed for brevity, see original site] Right-eye view of a color stereo pair for PIA11781

NASA Mars Exploration Rover Spirit used its navigation camera for the images assembled into this stereo, full-circle view of the rover's surroundings during the 1,802nd Martian day, or sol, (January 26, 2009) of Spirit's mission on the surface of Mars. South is at the center; north is at both ends.

This view combines images from the left-eye and right-eye sides of the navigation camera. It appears three-dimensional when viewed through red-blue glasses with the red lens on the left.

Spirit had driven down off the low plateau called 'Home Plate' on Sol 1782 (January 6, 2009) after spending 12 months on a north-facing slope on the northern edge of Home Plate. The position on the slope (at about the 9-o'clock position in this view) tilted Spirit's solar panels toward the sun, enabling the rover to generate enough electricity to survive its third Martian winter. Tracks at about the 11-o'clock position of this panorama can be seen leading back to that 'Winter Haven 3' site from the Sol 1802 position about 10 meters (33 feet) away. For scale, the distance between the parallel wheel tracks is about one meter (40 inches).

Where the receding tracks bend to the left, a circular pattern resulted from Spirit turning in place at a soil target informally named 'Stapledon' after William Olaf Stapledon, a British philosopher and science-fiction author who lived from 1886 to 1950. Scientists on the rover team suspected that the soil in that area might have a high concentration of silica, resembling a high-silica soil patch discovered east of Home Plate in 2007. Bright material visible in the track furthest to the right was examined with Spirit's alpha partical X-ray spectrometer and found, indeed, to be rich in silica.

The team laid plans to drive Spirit from this Sol 1802 location back up onto Home Plate, then southward for the rover's summer field season.

This view is presented as a cylindrical-perspective projection with geometric seam correction.

Using nonlinear ac electrokinetics vortex flow to enhance catalytic activities of sol-gel encapsulated trypsin in microfluidic devices

PubMed Central

Wang, Shau-Chun; Chen, Hsiao-Ping; Lai, Yi-Wen; Chau, Lai-Kwan; Chuang, Yu-Chun; Chen, Yi-Jie

2007-01-01

A novel microstirring strategy is applied to accelerate the digestion rate of the substrate Nα-benzoyl-L-arginine-4-nitroanilide (L-BAPA) catalyzed by sol-gel encapsulated trypsin. We use an ac nonlinear electrokinetic vortex flow to stir the solution in a microfluidic reaction chamber to reduce the diffusion length between the immobilized enzyme and substrate in the solution. High-intensity nonlinear electroosmotic microvortices, with angular speeds in excess of 1 cm∕s, are generated around a small (∼1.2 mm) conductive ion exchange granule when ac electric fields (133 V∕cm) are applied across a miniature chamber smaller than 10 μl. Coupling between these microvortices and the on-and-off electrophoretic motion of the granule in low frequency (0.1 Hz) ac fields produces chaotic stream lines to stir substrate molecules sufficiently. We demonstrate that, within a 5-min digestion period, the catalytic reaction rate of immobilized trypsin increases almost 30-fold with adequate reproducibility (15%) due to sufficient stirring action through the introduction of the nonlinear electrokinetic vortices. In contrast, low-frequency ac electroosmotic flow without the granule, provides limited stirring action and increases the reaction rate approximately ninefold with barely acceptable reproducibility (30%). Dye molecules are used to characterize the increases in solute diffusivity in the reaction reservoir in which sol-gel particles are placed, with and without the presence of granule, and compared with the static case. The solute diffusivity enhancement data show respective increases of ∼30 and ∼8 times, with and without the presence of granule. These numbers are consistent with the ratios of the enhanced reaction rate. PMID:19693360

Using nonlinear ac electrokinetics vortex flow to enhance catalytic activities of sol-gel encapsulated trypsin in microfluidic devices.

PubMed

Wang, Shau-Chun; Chen, Hsiao-Ping; Lai, Yi-Wen; Chau, Lai-Kwan; Chuang, Yu-Chun; Chen, Yi-Jie

2007-09-04

A novel microstirring strategy is applied to accelerate the digestion rate of the substrate N(alpha)-benzoyl-L-arginine-4-nitroanilide (L-BAPA) catalyzed by sol-gel encapsulated trypsin. We use an ac nonlinear electrokinetic vortex flow to stir the solution in a microfluidic reaction chamber to reduce the diffusion length between the immobilized enzyme and substrate in the solution. High-intensity nonlinear electroosmotic microvortices, with angular speeds in excess of 1 cms, are generated around a small ( approximately 1.2 mm) conductive ion exchange granule when ac electric fields (133 Vcm) are applied across a miniature chamber smaller than 10 mul. Coupling between these microvortices and the on-and-off electrophoretic motion of the granule in low frequency (0.1 Hz) ac fields produces chaotic stream lines to stir substrate molecules sufficiently. We demonstrate that, within a 5-min digestion period, the catalytic reaction rate of immobilized trypsin increases almost 30-fold with adequate reproducibility (15%) due to sufficient stirring action through the introduction of the nonlinear electrokinetic vortices. In contrast, low-frequency ac electroosmotic flow without the granule, provides limited stirring action and increases the reaction rate approximately ninefold with barely acceptable reproducibility (30%). Dye molecules are used to characterize the increases in solute diffusivity in the reaction reservoir in which sol-gel particles are placed, with and without the presence of granule, and compared with the static case. The solute diffusivity enhancement data show respective increases of approximately 30 and approximately 8 times, with and without the presence of granule. These numbers are consistent with the ratios of the enhanced reaction rate.

Chemistry of surface nanostructures in lead precursor-rich PbZr0.52Ti0.48O3 sol-gel films

NASA Astrophysics Data System (ADS)

Gueye, I.; Le Rhun, G.; Gergaud, P.; Renault, O.; Defay, E.; Barrett, N.

2016-02-01

We present a study of the chemistry of the nanostructured phase at the surface of lead zirconium titanate PbZr0.52Ti0.48O3 (PZT) films synthesized by sol-gel method. In sol-gel synthesis, excess lead precursor is used to maintain the target stoichiometry. Surface nanostructures appear at 10% excess whereas 30% excess inhibits their formation. Using the surface-sensitive, quantitative X-ray photoelectron spectroscopy and glancing angle X-ray diffraction we have shown that the chemical composition of the nanostructures is ZrO1.82-1.89 rather than pyrochlore often described in the literature. The presence of a possibly discontinuous layer of wide band gap ZrO1.82-1.89 could be of importance in determining the electrical properties of PZT-based metal-insulator-metal heterostructures.

Preparation of hydrophobic organic aeorgels

DOEpatents

Baumann, Theodore F.; Satcher, Jr., Joe H.; Gash, Alexander E.

2007-11-06

Synthetic methods for the preparation of hydrophobic organics aerogels. One method involves the sol-gel polymerization of 1,3-dimethoxybenzene or 1,3,5-trimethoxybenzene with formaldehyde in non-aqueous solvents. Using a procedure analogous to the preparation of resorcinol-formaldehyde (RF) aerogels, this approach generates wet gels that can be dried using either supercritical solvent extraction to generate the new organic aerogels or air dried to produce an xerogel. Other methods involve the sol-gel polymerization of 1,3,5 trihydroxy benzene (phloroglucinol) or 1,3 dihydroxy benzene (resorcinol) and various aldehydes in non-aqueous solvents. These methods use a procedure analogous to the one-step base and two-step base/acid catalyzed polycondensation of phloroglucinol and formaldehyde, but the base catalyst used is triethylamine. These methods can be applied to a variety of other sol-gel precursors and solvent systems. These hydrophobic organics aerogels have numerous application potentials in the field of material absorbers and water-proof insulation.

Preparation of hydrophobic organic aeorgels

DOEpatents

Baumann, Theodore F.; Satcher, Jr., Joe H.; Gash, Alexander E.

2004-10-19

Synthetic methods for the preparation of hydrophobic organics aerogels. One method involves the sol-gel polymerization of 1,3-dimethoxybenzene or 1,3,5-trimethoxybenzene with formaldehyde in non-aqueous solvents. Using a procedure analogous to the preparation of resorcinol-formaldehyde (RF) aerogels, this approach generates wet gels that can be dried using either supercritical solvent extraction to generate the new organic aerogels or air dried to produce an xerogel. Other methods involve the sol-gel polymerization of 1,3,5 trihydroxy benzene (phloroglucinol) or 1,3 dihydroxy benzene (resorcinol) and various aldehydes in non-aqueous solvents. These methods use a procedure analogous to the one-step base and two-step base/acid catalyzed polycondensation of phloroglucinol and formaldehyde, but the base catalyst used is triethylamine. These methods can be applied to a variety of other sol-gel precursors and solvent systems. These hydrophobic organics aerogels have numerous application potentials in the field of material absorbers and water-proof insulation.

Comparative study for highly Al and Mg doped ZnO thin films elaborated by sol gel method for photovoltaic application

NASA Astrophysics Data System (ADS)

El Hallani, G.; Nasih, S.; Fazouan, N.; Liba, A.; Khuili, M.; Sajieddine, M.; Mabrouki, M.; Laanab, L.; Atmani, E. H.

2017-04-01

Transparent conducting oxides such as ZnO doped with Al or Mg are commonly used in solar cells, light emitting diodes, photodetectors, and ultraviolet laser diodes. In our work, we focus on a comparative study of the structural, optical, and electrical properties of ZnO films highly doped with Al (AZO) and Mg (MZO). These films are deposited on glass substrates by the sol-gel spin coating method. The doping concentrations for Al and Mg are fixed to 5%-30%. The XRD spectra indicate that all the samples are polycrystalline with hexagonal wurtzite structures, exhibiting a preferred orientation along the (002) plane. Low degradation in crystallinity was observed for MZO even at a Mg concentration of 30%. The MgO phase started to appear compared to Al-doped layers where smaller grains are formed inducing a deterioration in the films just after doping but no new phase appeared. This result is in agreement with other experimental results [J. K. Rath, Sol. Energy Mater. Sol. Cells 76, 431-487 (2003); Morris et al., J. Appl. Phys. 67, 1079-1087 (1990)]. By AFM analysis, the results indicate a significantly rough surface for MZO compared to AZO films. For equal Al and Mg dopant concentrations, we observe that the transmittance spectra of MZO thin films are wider than those of AZO, indicating a shift toward shorter wavelengths with an optical gap energy equal to 3.67 eV. The electrical measurements of AZO and MZO thin films were made using the I-V characteristic obtained by the four probe method. All the films present an ohmic behavior. The conductivity and the mobility of AZO films were found to be better than those of MZO.

Electroosmotic flow and Joule heating in preparative continuous annular electrochromatography.

PubMed

Laskowski, René; Bart, Hans-Jörg

2015-09-01

An openFOAM "computational fluid dynamic" simulation model was developed for the description of local interaction of hydrodynamics and Joule heating in annular electrochromatography. A local decline of electrical conductivity of the background eluent is caused by an electrokinetic migration of ions resulting in higher Joule heat generation. The model equations consider the Navier-Stokes equation for incompressible fluids, the energy equation for stationary temperature fields, and the mass transfer equation for the electrokinetic flow. The simulations were embedded in commercial ANSYS Fluent software and in open-source environment openFOAM. The annular gap (1 mm width) contained an inorganic C8 reverse-phase monolith as stationary phase prepared by an in situ sol-gel process. The process temperature generated by Joule heating was determined by thermal camera system. The local hydrodynamics in the prototype was detected by a gravimetric contact-free measurement method and experimental and simulated values matched quite well. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Generation of a mesoporous silica MSU shell onto solid core silica nanoparticles using a simple two-step sol-gel process.

PubMed

Allouche, Joachim; Dupin, Jean-Charles; Gonbeau, Danielle

2011-07-14

Silica core-shell nanoparticles with a MSU shell have been synthesized using several non-ionic poly(ethylene oxide) based surfactants via a two step sol-gel method. The materials exhibit a typical worm-hole pore structure and tunable pore diameters between 2.4 nm and 5.8 nm.

Sol-gel method for encapsulating molecules

DOEpatents

Brinker, C. Jeffrey; Ashley, Carol S.; Bhatia, Rimple; Singh, Anup K.

2002-01-01

A method for encapsulating organic molecules, and in particular, biomolecules using sol-gel chemistry. A silica sol is prepared from an aqueous alkali metal silicate solution, such as a mixture of silicon dioxide and sodium or potassium oxide in water. The pH is adjusted to a suitably low value to stabilize the sol by minimizing the rate of siloxane condensation, thereby allowing storage stability of the sol prior to gelation. The organic molecules, generally in solution, is then added with the organic molecules being encapsulated in the sol matrix. After aging, either a thin film can be prepared or a gel can be formed with the encapsulated molecules. Depending upon the acid used, pH, and other processing conditions, the gelation time can be from one minute up to several days. In the method of the present invention, no alcohols are generated as by-products during the sol-gel and encapsulation steps. The organic molecules can be added at any desired pH value, where the pH value is generally chosen to achieve the desired reactivity of the organic molecules. The method of the present invention thereby presents a sufficiently mild encapsulation method to retain a significant portion of the activity of the biomolecules, compared with the activity of the biomolecules in free solution.

Lower Hybrid Wave Induced SOL Emissivity Variation at High Density on the Alcator C-Mod Tokamak

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

Faust, I.; Terry, J. L.; Reinke, M. L.

Lower Hybrid Current Drive (LHCD) in the Alcator C-Mod tokamak provides current profile control for the generation of Advanced Tokamak (AT) plasmas. Non-thermal electron bremsstrahlung emission decreases dramatically at n-bar{sub e}>1{center_dot}10{sup 20}[m{sup -3}] for diverted discharges, indicating low current drive efficiency. It is suggested that Scrape-Off-Layer (SOL) collisional absorption of LH waves is the cause for the absence of non-thermal electrons at high density. VUV and visible spectroscopy in the SOL provide direct information on collision excitation processes. Deuterium Balmer-, Lyman- and He-I transition emission measurements were used for initial characterization of SOL electron-neutral collisional absorption. Data from Helium andmore » Deuterium LHCD discharges were characterized by an overall increase in the emissivity as well as an outward radial shift in the emissivity profile with increasing plasma density and applied LHCD power. High-temperature, high-field (T{sub e} = 5keV,B{sub t} = 8T) helium discharges at high density display increased non-thermal signatures as well as reduced SOL emissivity. Variations in emissivity due to LHCD were seen in SOL regions not magnetically connected to the LH Launcher, indicating global SOL effects due to LHCD.« less

Sol-gel-processed yttrium-doped NiO as hole transport layer in inverted perovskite solar cells for enhanced performance

NASA Astrophysics Data System (ADS)

Hu, Zijun; Chen, Da; Yang, Pan; Yang, Lijun; Qin, Laishun; Huang, Yuexiang; Zhao, Xiaochong

2018-05-01

In this work, high-performance inverted planar perovskite solar cells (PSCs) using sol-gel processed Y-doped NiO thin films as hole transport layer (HTL) were demonstrated. Y-doped NiO thin films containing different Y doping concentrations were successfully prepared through a simple sol-gel process. The Y doping could significantly improve the electrical conductivity of NiO thin film, and the photovoltaic performance of Y-doped NiO HTL-based PSC devices outperformed that of the pristine NiO HTL-based device. Notably, the PSC using a 5%Y-NiO HTL exhibited the champion performance with an open-circuit voltage (Voc) of 1.00 V, a short circuit current density (Jsc) of 23.82 mA cm-2, a fill factor (FF) of 68% and a power conversion efficiency (PCE) of 16.31%, resulting in a 27.62% enhancement in PCE in comparison with the NiO device. The enhanced performance of the Y-doped NiO device could be attributed to the improved hole mobility, the high quality compact active layer morphology, the more efficient charge extraction from perovskite absorber as well as the lower recombination probability of charge carriers. Thus, this work provides a simple and effective approach to improve the electrical conductivity of p-type NiO thin films for use as a promising HTL in high performance PSCs.

Investigation into the formation of the scrape-off layer density shoulder in JET ITER-like wall L-mode and H-mode plasmas

NASA Astrophysics Data System (ADS)

Wynn, A.; Lipschultz, B.; Cziegler, I.; Harrison, J.; Jaervinen, A.; Matthews, G. F.; Schmitz, J.; Tal, B.; Brix, M.; Guillemaut, C.; Frigione, D.; Huber, A.; Joffrin, E.; Kruzei, U.; Militello, F.; Nielsen, A.; Walkden, N. R.; Wiesen, S.; Contributors, JET

2018-05-01

The low temperature boundary layer plasma (scrape-off layer or SOL) between the hot core and the surrounding vessel determines the level of power loading, erosion and implantation of material surfaces, and thus the viability of tokamak-based fusion as an energy source. This study explores mechanisms affecting the formation of flattened density profiles, so-called ‘density shoulders’, in the low-field side (LFS) SOL, which modify ion and neutral fluxes to surfaces—and subsequent erosion. We find that increases in SOL parallel resistivity, Λdiv (=[L || ν eiΩi]/c sΩe), postulated to lead to shoulder growth through changes in SOL turbulence characteristics, correlates with increases in SOL shoulder amplitude, A s, only under a subset of conditions (D2-fuelled L-mode density scans with outer strike point on the horizontal target). Λdiv fails to correlate with A s for cases of N2 seeding or during sweeping of the strike point across the horizontal target. The limited correlation of Λdiv and A s is also found for H-mode discharges. Thus, while it may be necessary for Λdiv to be above a threshold of ~1 for shoulder formation and/or growth, another mechanism is required. More significantly, we find that in contrast to parallel resistivity, outer divertor recycling, as quantified by the total outer divertor Balmer D α emission, I-D α , does scale with A s where Λdiv does and even where Λdiv does not. Divertor recycling could lead to SOL density shoulder formation through: (a) reducing the parallel to the field flow (loss) of ions out of the SOL to the divertor; and (b) changes in radial electric fields which lead to E  ×  B poloidal flows as well as potentially affecting SOL turbulence birth characteristics. Thus, changes in divertor recycling may be the sole process involved in bringing about SOL density shoulders or it may be that it acts in tandem with parallel resistivity.

Synthesis and properties of nanostructured sol-gel sorbents for simultaneous removal of sulfur dioxide and nitrogen oxides from flue gas

NASA Astrophysics Data System (ADS)

Buelna Quijada, Genoveva

2001-07-01

Regenerative, alumina-supported, copper-based sorbent/catalysts provide a promising technique for simultaneous removal of SO2 and NO x from flue gas. These sorbents can remove over 90% of SO2 and 70+% of NOx while generating no wastes, reducing energy consumption, and producing valuable by-products. The lack of a cost-effective sorbent with low attrition rate and good reactivity has been the main hurdle to commercialization of this copper oxide process. Developing such a sorbent is the focus of this dissertation. This work examines using sol-gel techniques rather than traditional processes to produce gamma-alumina and copper coated 7-alumina granular sorbents. Important modifications to the established sol-gel synthesis process were made, which minimized generated wastes and reduced preparation time and sorbent cost. A laboratory scale semi-continuous process providing a basis for large-scale synthesis was developed. The effect of the copper content on the surface area and dispersion of the active species on sol-gel-derived sorbents coated by the one step and wet-impregnation methods was studied. The sol-gel-derived sorbents showed superior sulfation and regeneration properties than the existing commercial sorbents used in the copper oxide process in terms of sulfation capacity, fast regeneration, recovery of sorption capacity, and SO2 concentration in the regenerated effluent. The optimum temperature for NO reduction by NH3 over sol-gel-derived CuO/gamma-Al2O3 was found to be 350°C for both fresh and sulfated catalysts. This was also the optimum operating temperature for simultaneous removal of SO2 and NOx from simulated flue gas. At 350°C, the adsorption capacity of the sol-gel sorbent/catalyst was higher than UOP's sorbent, and very close to the capacity of ALCOA's sorbent, while the catalytic activity for NO reduction of the sol-gel-derived CuO/gamma-Al 2O3 sorbent fell between the commercial sorbents. The new mesoporous sol-gel-derived materials showed larger surface area, better mechanical strength, and more uniform dispersion of the copper species than existing commercially available sorbents. The superior mechanical properties, better cost effectiveness, and comparable efficiency for simultaneous removal of SO2 and NOx of the sol-gel-derived CuO/gamma-Al 2O3 sorbents with respect to the commercial ones make them a good option for use in the copper oxide process for combined removal of SO2 and NOx from flue gas.

Development of a direct three-dimensional biomicrofabrication concept based on electrospraying a custom made siloxane sol

PubMed Central

Sullivan, Alice C.; Jayasinghe, Suwan N.

2007-01-01

We demonstrate here the discovery of a unique and direct three-dimensional biomicrofabrication concept possessing the ability to revolutionize the jet-based fabrication arena. Previous work carried out on similar jet-based approaches have been successful in fabricating only vertical wall∕pillar-structures by the controlled deposition of stacked droplets. However, these advanced jet-techniques have not been able to directly fabricate self-supporting arches∕links (without molds or reaction methods) between adjacent structures (walls or pillars). Our work reported here gives birth to a unique type of jet determined by high intensity electric fields, which is derived from a specially formulated siloxane sol. The sol studied here has been chosen for its attractive properties (such as an excellent cross-linking nature as well as the ability to polymerize via polycondensation on deposition to its biocompatability), which promotes direct forming of biostructures with nanometer (<50 nm) sized droplets in three dimensions. We foresee that this direct three-dimensional biomicrofabrication jet technique coupled with a variety of formulated sols having focused and enhanced functionality will be explored throughout the physical and life sciences. PMID:19693359

Three-dimensional scrape off layer transport in the helically symmetric experiment HSX

NASA Astrophysics Data System (ADS)

Akerson, A. R.; Bader, A.; Hegna, C. C.; Schmitz, O.; Stephey, L. A.; Anderson, D. T.; Anderson, F. S. B.; Likin, K. M.

2016-08-01

The edge topology of helically symmetric experiment (HSX) in the quasi-helically symmetric configuration is characterized by an 8/7 magnetic island remnant embedded in a short connection length scrape-off layer (SOL) domain. A 2D mapping of edge plasma profiles within this heterogeneous SOL has been constructed using a movable, multi-pin Langmuir probe. Comparisons of these measurements to edge simulations using the EMC3-EIRENE 3D plasma fluid and kinetic neutral gas transport model have been performed. The measurements provide strong evidence that particle transport is diffusive within the island region and dominantly convective in the SOL region. Measurements indicate that phenomenological cross-field diffusion coefficients are low in the SOL region between the last closed flux surface and edge island (i.e. {{D}\\bot}≈ 0.03 m2 s-1). This level of transport was found to increase by a factor of two when a limiter is inserted almost completely into the magnetic island. A reduction in gradients of the edge electrostatic plasma potential was also measured in this configuration, suggesting that the reduced electric field may be linked to the increased cross-field transport observed.

Sol-gel-Derived nano-sized double layer anti-reflection coatings (SiO2/TiO2) for low-cost solar cell fabrication.

PubMed

Lee, Seung Jun; Hur, Man Gyu; Yoon, Dae Ho

2013-11-01

We investigate nano-sized double layer anti-reflection coatings (ARCs) using a TiO2 and SiO2 sol-gel solution process for mono-crystalline silicon solar cells. The process can be easily adapted for spraying sol-gel coatings to reduce manufacturing cost. The spray-coated SiO2/TiO2 nano-sized double layer ARCs were deposited on mono-crystalline silicon solar cells, and they showed good optical properties. The spray coating process is a lower-cost fabrication process for large-scale coating than vacuum deposition processes such as PECVD. The measured average optical reflectance (300-1200 nm) was about approximately 8% for SiO2/TiO2 nano-sized double layer ARCs. The electrical parameters of a mono-crystalline silicon solar cell and reflection losses show that the SiO2/TiO2 stacks can improve cell efficiency by 0.2% compared to a non-coated mono-crystalline silicon solar cell. In the results, good correlation between theoretical and experimental data was obtained. We expect that the sol-gel spray-coated mono-crystalline silicon solar cells have high potential for low-cost solar cell fabrication.

75 FR 71613 - Mandatory Reliability Standards for Interconnection Reliability Operating Limits

Federal Register 2010, 2011, 2012, 2013, 2014

2010-11-24

... Reliability Standards. The proposed Reliability Standards were designed to prevent instability, uncontrolled... Reliability Standards.\\2\\ The proposed Reliability Standards were designed to prevent instability... the SOLs, which if exceeded, could expose a widespread area of the bulk electric system to instability...

Radiation hardening of sol gel-derived silica fiber preforms through fictive temperature reduction.

PubMed

Hari Babu, B; Lancry, Matthieu; Ollier, Nadege; El Hamzaoui, Hicham; Bouazaoui, Mohamed; Poumellec, Bertrand

2016-09-20

The impact of fictive temperature (T_f) on the evolution of point defects and optical attenuation in non-doped and Er³⁺-doped sol-gel silica glasses was studied and compared to Suprasil F300 and Infrasil 301 glasses before and after γ-irradiation. To this aim, sol-gel optical fiber preforms have been fabricated by the densification of erbium salt-soaked nanoporous silica xerogels through the polymeric sol-gel technique. These γ-irradiated fiber preforms have been characterized by FTIR, UV-vis-NIR absorption spectroscopy, electron paramagnetic resonance, and photoluminescence measurements. We showed that a decrease in the glass fictive temperature leads to a decrease in the glass disorder and strained bonds. This mainly results in a lower defect generation rate and thus less radiation-induced attenuation in the UV-vis range. Furthermore, it was found that γ-radiation "hardness" is higher in Er³⁺-doped sol-gel silica compared to un-doped sol-gel silica and standard synthetic silica glasses. The present work demonstrates an effective strategy to improve the radiation resistance of optical fiber preforms and glasses through glass fictive temperature reduction.

Effect of Cu-doping on structural and electrical properties of Ni0.4-xCu0.3+xMg0.3Fe2O4 ferrites prepared using sol-gel method

NASA Astrophysics Data System (ADS)

Dhaou, Mohamed Houcine

2018-06-01

Ni0.4-xCu0.3+xMg0.3Fe2O4 spinel ferrites were prepared by sol-gel technique. X-ray diffraction results indicate that ferrite samples have a cubic spinel-type structure with ? space group. The electrical properties of the studied samples using complex impedance spectroscopy technique have been investigated as a function of frequency at different temperatures. We found that the addition of copper in Ni0.4-xCu0.3+xMg0.3Fe2O4 ferrite system can improve its conductivity. Dielectric properties have been discussed in terms of hopping of charge carriers between Fe2+ and Fe3+ ions. For all samples, frequency dependence of the imaginary part of impedance (Z") shows the existence of relaxation phenomenon. The appropriate equivalent circuit configuration for modeling the Nyquist plots of impedance is of the type of (Rg + Rgb//Cgb).

Investigation of electrical studies of spinel FeCo2O4 synthesized by sol-gel method

NASA Astrophysics Data System (ADS)

Lobo, Laurel Simon; Kalainathan, S.; Kumar, A. Ruban

2015-12-01

In this work, spinel FeCo2O4 is synthesized by sol-gel method using succinic acid as a chelating agent at 900 °C. The structural, spectroscopic and morphological characterization was carried out by using X-ray diffraction (XRD), Fourier Transform Infrared Spectroscopy (FT-IR) and Scanning Electron Microscopy equipped with Energy Dispersive X-ray spectrometer (SEM-EDX). The M-H loop at room temperature confirms the ferromagnetic property of the sample. The frequency and temperature dependence of dielectric constant (εʹ) and dielectric loss (tan δ) shows the presence of Maxwell-Wagner relaxation in the sample due to the presence of oxygen vacancy. Nyquist plot for frequency and temperature domain signifies the presence of grain effect, grain boundary effect and electrode interface in the conduction process. Electric modulus under suppression of electrode polarization shows the grain and grain boundary effects. The electrode polarization is observed in the lower frequency range of the conductivity graph.

Effect of annealing temperature on microstructural evolution and electrical properties of sol-gel processed ZrO2/Si films

NASA Astrophysics Data System (ADS)

Hwang, Soo Min; Lee, Seung Muk; Park, Kyung; Lee, Myung Soo; Joo, Jinho; Lim, Jun Hyung; Kim, Hyoungsub; Yoon, Jae Jin; Kim, Young Dong

2011-01-01

High-permittivity (k) ZrO2/Si(100) films were fabricated by a sol-gel technique and the microstructural evolution with the annealing temperature (Ta) was correlated with the variation of their electrical performance. With increasing Ta, the ZrO2 films crystallized into a tetragonal (t) phase which was maintained until 700 °C at nanoscale thicknesses. Although the formation of the t-ZrO2 phase obviously enhanced the k value of the ZrO2 dielectric layer, the maximum capacitance in accumulation was decreased by the growth of a low-k interfacial layer (IL) between ZrO2 and Si with increasing Ta. On the other hand, the gate leakage current was remarkably depressed with increasing Ta probably due to the combined effects of the increased IL thickness, optical band gap of ZrO2, and density of ZrO2 and decreased remnant organic components.

Water Density in the Electric Double Layer at the Insulator/Electrolyte Solution Interface

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

Tikhonov,A.

I studied the spatial structure of the thick transition region between n-hexane and a colloidal solution of 7-nm silica particles by X-ray reflectivity and grazing incidence small-angle scattering. The interfacial structure is discussed in terms of a semiquantitative interface model wherein the potential gradient at the n-hexane/sol interface reflects the difference in the potentials of 'image forces' between the cationic Na{sup +} and anions (nanoparticles) and the specific adsorption of surface charge at the interface between the adsorbed layer and the solution, as well as at the interface between the adsorbed layer and n-hexane. The X-ray scattering data revealed thatmore » the average density of water in the field {approx}10{sup 9}-10{sup 10} V/m of the electrical double layer at the hexane/silica sol interface is the same as, or only few percent higher (1-7%) than, its density under normal conditions.« less

Mesoporous hollow spheres from soap bubbling.

PubMed

Yu, Xianglin; Liang, Fuxin; Liu, Jiguang; Lu, Yunfeng; Yang, Zhenzhong

2012-02-01

The smaller and more stable bubbles can be generated from the large parent bubbles by rupture. In the presence of a bubble blowing agent, hollow spheres can be prepared by bubbling a silica sol. Herein, the trapped gas inside the bubble acts as a template. When the porogen, i.e., other surfactant, is introduced, a mesostructured shell forms by the co-assembly with the silica sol during sol-gel process. Morphological evolution emphasizes the prerequisite of an intermediate interior gas flow rate and high exterior gas flow rate for hollow spheres. The method is valid for many compositions from inorganic, polymer to their composites. Copyright © 2011 Elsevier Inc. All rights reserved.

Sol-Generating Chemical Vapor into Liquid (SG-CViL) deposition – A facile method for encapsulation of diverse cell types in silica matrices

DOE PAGES

Johnston, Robert; Rogelj, Snezna; Harper, Jason C.; ...

2014-12-12

In nature, cells perform a variety of complex functions such as sensing, catalysis, and energy conversion which hold great potential for biotechnological device construction. However, cellular sensitivity to ex vivo environments necessitates development of bio–nano interfaces which allow integration of cells into devices and maintain their desired functionality. In order to develop such an interface, the use of a novel Sol-Generating Chemical Vapor into Liquid (SG-CViL) deposition process for whole cell encapsulation in silica was explored. In SG-CViL, the high vapor pressure of tetramethyl orthosilicate (TMOS) is utilized to deliver silica into an aqueous medium, creating a silica sol. Cellsmore » are then mixed with the resulting silica sol, facilitating encapsulation of cells in silica while minimizing cell contact with the cytotoxic products of silica generating reactions (i.e. methanol), and reduce exposure of cells to compressive stresses induced from silica condensation reactions. Using SG-CVIL, Saccharomyces cerevisiae (S. cerevisiae) engineered with an inducible beta galactosidase system were encapsulated in silica solids and remained both viable and responsive 29 days post encapsulation. By tuning SG-CViL parameters, thin layer silica deposition on mammalian HeLa and U87 human cancer cells was also achieved. Thus, the ability to encapsulate various cell types in either a multi cell (S. cerevisiae) or a thin layer (HeLa and U87 cells) fashion shows the promise of SG-CViL as an encapsulation strategy for generating cell–silica constructs with diverse functions for incorporation into devices for sensing, bioelectronics, biocatalysis, and biofuel applications.« less

Enhancing Optical and Electrical Properties of La- and Al-Codoped ZnO Thin Films Prepared by Sol-Gel Method -La Codoping Effect.

PubMed

He-Yan, Hai

2017-07-10

Backgroud: The transparent conductive ZnO film is widely used in solar cell. Enhancing the transmittance and electrical conductivity of the films is attracting many attentions to improve cell efficiency. This work focuses on the fabrication and potential application of the various cation-doped ZnO materials in recent patents and literature and then presents the La codoping effects of Al-doped ZnO films. Films were deposited by a sol-gel route and characterized by various techniques including X-ray diffraction, scanning electron microscopy, energy dispersive spectroscopy, UV-vis and luminescent spectroscopies, and electrical conduction analysis. The UV-vis. transmittance and band gap increased and then decreased, whereas the resistivity decreased and then slightly increased with the increase in La/Al ratio. The La/Al ratio of 0.0105 led to a maximal transmittance, a widest band gap, and a minimal resistivity. The films also illustrated a near band gap emission and some intrinsic defect-related emissions with varied intensity with La/Al ratio. This work reveal that the electrical and optical properties of the ZnO:Al films can be well enhanced by La codoping. This is significant to the applications of the ZnO:Al materials. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Effect of Annealing Temperature on Structural, Optical, and Electrical Properties of Sol-Gel Spin-Coating-Derived Cu2ZnSnS4 Thin Films

NASA Astrophysics Data System (ADS)

Hosseinpour, Rabie; Izadifard, Morteza; Ghazi, Mohammad Ebrahim; Bahramian, Bahram

2018-02-01

The effect of annealing temperature on structural, optical, and electrical properties of Cu2ZnSnS4 (CZTS) thin films grown on a glass substrate by spin coating sol-gel technique has been studied. Structural study showed that all samples had kesterite crystalline structure. Scanning electron microscopy images showed that the crystalline quality of the samples was improved by heat treatment. Optical study showed that the energy gap values for the samples ranged from 1.55 eV to 1.78 eV. Moreover, good optical conductivity values (1012 S-1 to 1014 S-1) were obtained for the samples. Investigation of the electrical properties of the CZTS thin films showed that the carrier concentration increased significantly with the annealing temperature. The photoelectrical behavior of the samples revealed that the photocurrent under light illumination increased significantly. Overall, the results show that the CZTS thin films annealed at 500°C had better structural, optical, and electrical properties and that such CZTS thin films are desirable for use as absorber layers in solar cells. The photovoltaic properties of the CZTS layer annealed at 500°C were also investigated and the associated figure of merit calculated. The results showed that the fabricated ZnS-CZTS heterojunction exhibited good rectifying behavior but rather low fill factor.

Grain size effect on activation energy in spinel CoFe{sub 2}O{sub 4} ceramic

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

Supriya, Sweety, E-mail: sweety@iitp.ac.in; Kumar, Sunil; Kar, Manoranjan

2016-05-23

Cobalt ferrite of different average crystallites (from nanocrystallite to micro crystallites) has been prepared by the Sol-Gel Method. The X-ray diffraction (XRD) analysis confirms the cubic spinel phase with no trace of impurity phases. The effect of annealing temperature on micro structure and electric transport properties as a function of frequency and temperature has been studied. It is observed that the electric impedance and conductivity are strongly dependent on grain size. The impedance spectroscopic study is employed to understand the electrical transport properties of cobalt ferrite.

Heat flux and plasma flow in the far scrape-off layer of the inboard poloidal field null configuration in QUEST

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

Onchi, T.; Zushi, H.; Hanada, K.

2015-08-15

Heat flux and plasma flow in the scrape-off layer (SOL) are examined for the inboard poloidal field null (IPN) configuration of the spherical tokamak QUEST. In the plasma current (I{sub p}) ramp-up phase, high heat flux (>1 MW/m{sup 2}) and supersonic flow (Mach number M > 1) are found to be present simultaneously in the far-SOL. The heat flux is generated by energetic electrons excursed from the last closed flux surface. Supersonic flows in the poloidal and toroidal directions are correlated with each other. In the quasi-steady state, sawtooth-like oscillation of I{sub p} at 20 Hz is observed. Heat flux and subsonic plasma flowmore » in the far-SOL are modified corresponding to the I{sub p}-oscillation. The heat flow caused by motion of energetic electrons and the bulk-particle transport to the far-SOL is enhanced during the low-I{sub p} phase. Modification of plasma flow in the far SOL occurs earlier than the I{sub p} crash. The M–I{sub p} curve has a limit-cycle characteristic with sawtooth-like oscillation. Such a core–SOL relationship indicates that the far-SOL flow plays an important role in sustaining the oscillation of I{sub p} in the IPN configuration.« less

Solvation Thermodynamics of Oligoglycine with Respect to Chain Length and Flexibility.

PubMed

Drake, Justin A; Harris, Robert C; Pettitt, B Montgomery

2016-08-23

Oligoglycine is a backbone mimic for all proteins and is prevalent in the sequences of intrinsically disordered proteins. We have computed the absolute chemical potential of glycine oligomers at infinite dilution by simulation with the CHARMM36 and Amber ff12SB force fields. We performed a thermodynamic decomposition of the solvation free energy (ΔG(sol)) of Gly2-5 into enthalpic (ΔH(sol)) and entropic (ΔS(sol)) components as well as their van der Waals and electrostatic contributions. Gly2-5 was either constrained to a rigid/extended conformation or allowed to be completely flexible during simulations to assess the effects of flexibility on these thermodynamic quantities. For both rigid and flexible oligoglycine models, the decrease in ΔG(sol) with chain length is enthalpically driven with only weak entropic compensation. However, the apparent rates of decrease of ΔG(sol), ΔH(sol), ΔS(sol), and their elec and vdw components differ for the rigid and flexible models. Thus, we find solvation entropy does not drive aggregation for this system and may not explain the collapse of long oligoglycines. Additionally, both force fields yield very similar thermodynamic scaling relationships with respect to chain length despite both force fields generating different conformational ensembles of various oligoglycine chains. Copyright © 2016 Biophysical Society. Published by Elsevier Inc. All rights reserved.

Band alignment and optical response of facile grown NiO/ZnO nano-heterojunctions

NASA Astrophysics Data System (ADS)

Sultan, Muhammad; Mumtaz, Sundas; Ali, Asad; Khan, Muhammad Yaqoob; Iqbal, Tahir

2017-12-01

ZnO nanorods decorated by NiO nanostructures were fabricated using facile chemical route. The nanorods of ZnO were prepared by using chemical bath deposition technique and subsequently decorated by NiO using sol-gel spin coating. The density and orientation of the ZnO nanorods was controlled through the seed layer with preferential growth along c-axis and hexagonal face. X-Ray Photoelectron Spectroscopy (XPS) analysis was used to confirm stoichiometry of the materials and band alignment study of the heterostructures. Type-II band alignment was observed from the experimental results. The IV characteristics of the device depicting rectifying behavior at different temperatures were observed with photocurrent generation in response to light excitation. The electrical properties reported in this study are in line with earlier work where heterojunctions were fabricated by physical deposition techniques.

Ultrafast Sol-Gel Synthesis of Graphene Aerogel Materials

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

Lim, Mathew; Hu, Matthew; Manandhar, Sandeep

2015-12-01

Graphene aerogels derived from graphene-oxide (GO) starting materials recently have been shown to exhibit a combination of high electrical conductivity, chemical stability, and low cost that has enabled a range of electrochemical applications. Standard synthesis protocols for manufacturing graphene aerogels require the use of sol-gel chemical reactions that are maintained at high temperatures for long periods of time ranging from 12 hours to several days. Here we report an ultrafast, acid-catalyzed sol-gel formation process in acetonitrile in which wet GO-loaded gels are realized within 2 hours at temperatures below 45°C. Spectroscopic and electrochemical analysis following supercritical drying and pyrolysis confirmsmore » the reduction of the GO in the aerogels to sp2 carbon crystallites with no residual carbon–nitrogen bonds from the acetonitrile or its derivatives. This rapid synthesis enhances the prospects for large-scale manufacturing of graphene aerogels for use in numerous applications including sorbents for environmental toxins, support materials for electrocatalysis, and high-performance electrodes for electrochemical capacitors and solar cells.« less

Phoenix Conductivity Probe Inserted into Martian Soil

NASA Technical Reports Server (NTRS)

2008-01-01

NASA's Phoenix Mars Lander inserted the four needles of its thermal and conductivity probe into Martian soil during the 98th Martian day, or sol, of the mission and left it in place until Sol 99 (Sept. 4, 2008).

The Robotic Arm Camera on Phoenix took this image on the morning of Sol 99 while the probe's needles were in the ground. The science team informally named this soil target 'Gandalf.'

The thermal and conductivity probe measures how fast heat and electricity move from one needle to an adjacent one through the soil or air between the needles. Conductivity readings can be indicators about water vapor, water ice and liquid water.

The probe is part of Phoenix's Microscopy, Electrochemistry and Conductivity suite of instruments.

The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is by NASA's Jet Propulsion Laboratory, Pasadena, Calif. Spacecraft development is by Lockheed Martin Space Systems, Denver.

A Sequential Quadratic Programming Algorithm Using an Incomplete Solution of the Subproblem

DTIC Science & Technology

1990-09-01

Electr6nica e Inform’itica Industrial E.T.S. Ingenieros Industriales Universidad Polit6cnica, Madrid Technical Report SOL 90-12 September 1990 -Y...MURRAY* AND FRANCISCO J. PRIETOt *Systems Optimization Laboratory Department of Operations Research Stanford University tDept. de Automitica, Ingenieria

The Role of an Electric Field in the Formation of a Detached Regime in Tokamak Plasma

NASA Astrophysics Data System (ADS)

Senichenkov, I.; Kaveeva, E.; Rozhansky, V.; Sytova, E.; Veselova, I.; Voskoboynikov, S.; Coster, D.

2018-03-01

Modeling of the transition to the detachment of ASDEX Upgrade tokamak plasma with increasing density is performed using the SOLPS-ITER numerical code with a self-consistent account of drifts and currents. Their role in plasma redistribution both in the confinement region and in the scrape-off layer (SOL) is investigated. The mechanism of high field side high-density formation in the SOL in the course of detachment is suggested. In the full detachment regime, when the cold plasma region expands above the X-point and reaches closed magnetic-flux surfaces, plasma perturbation in a confined region may lead to a change in the confinement regime.

Structural, optical, and electrical properties of Ni-doped ZnO nanorod arrays prepared via sonicated sol-gel immersion method

NASA Astrophysics Data System (ADS)

Ismail, A. S.; Mamat, M. H.; Malek, M. F.; Saidi, S. A.; Yusoff, M. M.; Mohamed, R.; Sin, N. D. Md; Suriani, A. B.; Rusop, M.

2018-05-01

Nickel (Ni)-doped zinc oxide (ZnO) nanorod array films were synthesised using sonicated sol-gel immersion method. The FESEM images showed that the Ni-doped ZnO nanorod arrays possess hexagonal shape with average diameter about 120 nm and thickness about 1.10 µm. The Ni-doped ZnO nanorod arrays possess better transmittance properties with 3.27 eV of optical band gap energy and 40 meV of urbach energy. The current-voltage (I-V) measurement indicated that the conductivity of ZnO film slightly improved with Ni-doping. The doped film displayed good humidity sensing performance with sensitivity of 1.21.

Curiosity Drill After Drilling at Telegraph Peak

NASA Image and Video Library

2015-03-06

This view from the Mast Camera (Mastcam) on NASA's Curiosity Mars rover shows the rover's drill just after finishing a drilling operation at a target rock called "Telegraph Peak" on Feb. 24, 2015, the 908th Martian day, or sol, of the rover's work on Mars. Three sols later, a fault-protection action by the rover halted a process of transferring sample powder that was collected during this drilling. The image is in raw color, as recorded directly by the camera, and has not been white-balanced. The fault-protection event, triggered by an irregularity in electrical current, led to engineering tests in subsequent days to diagnose the underlying cause. http://photojournal.jpl.nasa.gov/catalog/PIA19145

Anomalously large bend elastic constant and faster electro-optic response in anisotropic gels formed by a dipeptide

NASA Astrophysics Data System (ADS)

Bhargavi, R.; Nair, Geetha G.; Prasad, S. Krishna; Prabhu, Rashmi; Yelamaggad, C. V.

2011-04-01

We report rheological, static, and dynamic Freedericksz transformation measurements on an anisotropic thermoreversible gel formed by gelation of a nematic liquid crystal (NLC) with a monodisperse dipeptide. The storage and loss modulii obtained from a low strain oscillatory shear experiment display that the material forms a weak anisotropic gel, and undergoes a sharp thermal transition to an anisotropic sol state. Freedericksz transformation studies employing an electric field for the reorientation of the molecules present a surprising result: the gel possesses a very large Frank bend elastic constant value, which is orders of magnitude higher than that for the high temperature sol state as well as that for the neat NLC used. On the other hand, the splay elastic constant shows relatively a small increase. Further, these elastic constants show systematic but nonlinear variation with the concentration of the gelator. Attractive features of the electro-optic switching when the sol transforms to the gel state are the vanishing of the undesirable backflow effect, and nearly an order of magnitude decrease in the switching speed. In both the gel and sol states the extracted rotational viscosities are comparable to the values of the neat NLC at corresponding temperatures. In contrast, the bulk dynamic viscosity is more than three orders of magnitude higher in the gel. The studies also demonstrate that the anisotropic gel to anisotropic sol transition seen in this weak gel can be tracked by simply monitoring the static or the dynamic Freedericksz transformation.

Sol-gel niobia sorbent with a positively charged octadecyl ligand providing enhanced enrichment of nucleotides and organophosphorus pesticides in capillary microextraction for online HPLC analysis.

PubMed

Kesani, Sheshanka; Malik, Abdul

2018-04-01

A niobia-based sol-gel organic-inorganic hybrid sorbent carrying a positively charged C 18 ligand (Nb 2 O 5 -C 18 (+ve)) was synthesized to achieve enhanced enrichment capability in capillary microextraction of organophosphorus compounds (which include organophosphorus pesticides and nucleotides) before their online analysis by high-performance liquid chromatography. The sorbent was designed to simultaneously provide three different types of molecular level interactions: electrostatic, Lewis acid-base, and van der Waals interactions. To understand relative contributions of various molecular level analyte-sorbent interactions in the extraction process, two other sol-gel niobia sorbents were also created: (a) a purely inorganic sol-gel niobia sorbent (Nb 2 O 5 ) and (b) an organic-inorganic hybrid sol-gel niobia sorbent carrying an electrically neutral-bonded octadecyl ligand (Nb 2 O 5 -C 18 ). The extraction efficiency of the created sol-gel niobia sorbent (Nb 2 O 5 -C 18 (+ve)) was compared with that of analogously designed and synthesized titania-based sol-gel sorbent (TiO 2 -C 18 (+ve)), taking into consideration that titania-based sorbents present state-of-the-art extraction media for organophosphorus compounds. In capillary microextraction with high-performance liquid chromatography analysis, Nb 2 O 5 -C 18 (+ve) had shown 40-50% higher specific extraction values (a measure of extraction efficiency) over that of TiO 2 -C 18 (+ve). Compared to TiO 2 -C 18 (+ve), Nb 2 O 5 -C 18 (+ve) also provided superior analyte desorption efficiency (96 vs. 90%) during the online release of the extracted organophosphorus pesticides from the sorbent coating in the capillary microextraction capillary to the chromatographic column using reversed-phase high-performance liquid chromatography mobile phase. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Use of sol-gels as solid matrixes for simultaneous multielement determination by radio frequency glow discharge optical emission spectrometry: determinations of suspended particulate matter.

PubMed

Davis, W Clay; Knippel, Brad C; Cooper, Julia E; Spraul, Bryan K; Rice, Jeanette K; Smith, Dennis W; Marcus, R Kenneth

2003-05-15

A new approach for the analysis of particulate matter by radio frequency glow discharge optical emission spectrometry (rf-GD-OES) is described. Dispersion of the particles in a sol-gel sample matrix provides a convenient means of generating a thin film suitable for sputter-sampling into the discharge. Acid-catalyzed sol-gel glasses synthesized from tetramethyl orthosilicate were prepared and spun-cast on glass substrates. The resultant thin films on glass substrates were analyzed to determine the discharge operating conditions and resultant sputtering characteristics while a number of optical emission lines of the film components were monitored. Slurries of powdered standard reference materials NIST SRM 1884a (Portland Cement) and NIST SRM 2690 (Coal Fly Ash) dispersed in the sols were cast into films in the same manner. Use of the sol-gels as sample matrixes allows for background subtraction through the use of analytical blanks and may facilitate the generation of calibration curves via readily synthesized, matrix-matched analytical standards in solids analysis. Detection limits were determined for minor elements via the RSDB method to be in the range of 1-10 microg/g in Portland Cement and Coal Fly Ash samples for the elements Al, Fe, Mg, S, and Si. Values for Ca were in the range of 15-35 microg/g. This preliminary study demonstrates the possibility of incorporating various insoluble species, including ceramics and geological specimens in powder form, into a solid matrix for further analysis by either rf-GD-OES or MS.

Self-excitation of single nanomechanical pillars

NASA Astrophysics Data System (ADS)

Kim, Hyun S.; Qin, Hua; Blick, Robert H.

2010-03-01

Self-excitation is a mechanism that is ubiquitous for electromechanical power devices such as electrical generators. This is conventionally achieved by making use of the magnetic field component in electrical generators (Nedic and Lipo 2000 IEEE/IAS Conf. Records (Rome, Italy) vol 1 pp 51-6), a good and widely visible example of which is the wind turbine farm (Muljadi et al 2005 J. Sol. Energy Eng. 127 581-7). In other words, a static force, such as the wind acting on rotor blades, can generate a resonant excitation at a certain mechanical frequency. For nanomechanical systems (Craighead 2000 Science 290 1532-5 Roukes 2001 Phys. World 14 25-31 Cleland 2003 Foundations of Nanomechanics (Berlin: Springer); Ayari et al 2007 Nano Lett. 7 2252-7 Koenig et al 2008 Nat. Nanotechnol. 3 482-4) such a self-excitation (SE) mechanism is also highly desirable, because it can generate mechanical oscillations at radio frequencies by simply applying a dc bias voltage. This is of great importance for low-power signal communication devices and detectors, as well as for mechanical computing elements. For a particular nanomechanical system—the single electron shuttle—this effect was predicted some time ago by Gorelik et al (Phys. Rev. Lett. 80 4526-9). Here, we use a nanoelectromechanical single electron transistor (NEMSET) to demonstrate self-excitation for both the soft and hard regimes, respectively. The ability to use self-excitation in nanomechanical systems may enable the detection of quantum mechanical backaction effects (Naik et al 2006 Nature 443 193-6) in direct tunneling, macroscopic quantum tunneling (Savelev et al 2006 New J. Phys. 8 105-15) and rectification (Pistolesi and Fazio 2005 Phys. Rev. Lett. 94 036806-4). All these effects have so far been overshadowed by the large driving voltages that had to be applied.

Solution-Processed Gallium–Tin-Based Oxide Semiconductors for Thin-Film Transistors

PubMed Central

Zhang, Xue; Lee, Hyeonju; Kim, Jungwon; Kim, Eui-Jik; Park, Jaehoon

2017-01-01

We investigated the effects of gallium (Ga) and tin (Sn) compositions on the structural and chemical properties of Ga–Sn-mixed (Ga:Sn) oxide films and the electrical properties of Ga:Sn oxide thin-film transistors (TFTs). The thermogravimetric analysis results indicate that solution-processed oxide films can be produced via thermal annealing at 500 °C. The oxygen deficiency ratio in the Ga:Sn oxide film increased from 0.18 (Ga oxide) and 0.30 (Sn oxide) to 0.36, while the X-ray diffraction peaks corresponding to Sn oxide significantly reduced. The Ga:Sn oxide film exhibited smaller grains compared to the nanocrystalline Sn oxide film, while the Ga oxide film exhibited an amorphous morphology. We found that the electrical properties of TFTs significantly improve by mixing Ga and Sn. Here, the optimum weight ratio of the constituents in the mixture of Ga and Sn precursor sols was determined to be 1.0:0.9 (Ga precursor sol:Sn precursor sol) for application in the solution-processed Ga:Sn oxide TFTs. In addition, when the Ga(1.0):Sn(0.9) oxide film was thermally annealed at 900 °C, the field-effect mobility of the TFT was notably enhanced from 0.02 to 1.03 cm2/Vs. Therefore, the mixing concentration ratio and annealing temperature are crucial for the chemical and morphological properties of solution-processed Ga:Sn oxide films and for the TFT performance. PMID:29283408

Electric-Field-Oriented Growth of Long Hair-Like Silica Microfibrils and Derived Functional Monolithic Solids

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

Hu, Michael Z.; DePaoli, David W.; Kuritz, Tanya

We present a “bottom-up” fabrication approach to first grow a new class of inorganic (silica) long hair-like microfibers or microwires and then to form monolithic solid pellet that contains parallel arrays of bundled microfibers with a controlled orientation. During the sol-gel solution processing, reactive precursor species are utilized as molecular “building blocks” for the field-directed assembly growth of microfibers driven by an electric field of pulsed direct current (dc) with controlled frequency. In principle, this reactive electrofibrilation process that combines an external field with a solid-phase nucleation and growth process has no limitation on reactions (such as the one heremore » that involves sol-gel reaction chemistry) and on materials compositions (such as the example silica oxide), thus will enable bulk production of long microfibers of wide variety of inorganic materials (other oxides or metals). Furthermore, we have fabricated uniquely architectured monolithic solid materials containing aligned microfibers by “wet press” of the in-situ grown microfiber structure in the electric field. The consolidated monolithic slabs (1 cm x 1 cm x 3 mm) have shown anisotropic properties and desirable retention of DNA molecule fragments, thus, could serve as a platform stationary-phase materials for future development of capillary electrochromatography for biomolecule separations.« less

Electric-Field-Oriented Growth of Long Hair-Like Silica Microfibrils and Derived Functional Monolithic Solids

DOE PAGES

Hu, Michael Z.; DePaoli, David W.; Kuritz, Tanya; ...

2017-09-11

We present a “bottom-up” fabrication approach to first grow a new class of inorganic (silica) long hair-like microfibers or microwires and then to form monolithic solid pellet that contains parallel arrays of bundled microfibers with a controlled orientation. During the sol-gel solution processing, reactive precursor species are utilized as molecular “building blocks” for the field-directed assembly growth of microfibers driven by an electric field of pulsed direct current (dc) with controlled frequency. In principle, this reactive electrofibrilation process that combines an external field with a solid-phase nucleation and growth process has no limitation on reactions (such as the one heremore » that involves sol-gel reaction chemistry) and on materials compositions (such as the example silica oxide), thus will enable bulk production of long microfibers of wide variety of inorganic materials (other oxides or metals). Furthermore, we have fabricated uniquely architectured monolithic solid materials containing aligned microfibers by “wet press” of the in-situ grown microfiber structure in the electric field. The consolidated monolithic slabs (1 cm x 1 cm x 3 mm) have shown anisotropic properties and desirable retention of DNA molecule fragments, thus, could serve as a platform stationary-phase materials for future development of capillary electrochromatography for biomolecule separations.« less

Fabrication and characterization of highly transparent and conductive indium tin oxide films made with different solution-based methods

NASA Astrophysics Data System (ADS)

Xia, N.; Gerhardt, R. A.

2016-11-01

Solution-based fabrication methods can greatly reduce the cost and broaden the applications of transparent conducting oxides films, such as indium tin oxide (ITO) films. In this paper, we report on ITO films fabricated by spin coating methods on glass substrates with two different ITO sources: (1) a commercial ITO nanopowder water dispersion and (2) a sol-gel ITO solution. A simple and fast air annealing process was used to treat as-coated ITO films on a controlled temperature hot plate. Thermogravimetric analysis and x-ray diffraction showed that highly crystalline ITO films were formed after the annealing steps. The final ITO films had a good combination of optical properties and electrical properties, especially for films made from five layers of sol-gel ITO (92.66% transmittance and 8.7 × 10-3 Ω cm resistivity). The surface morphology and conducting network on the ITO films were characterized by non-contact and current atomic force microscopy. It was found that conducting paths were only partially connected for the nanoparticle ITO dispersion films, whereas the sol-gel ITO films had a more uniformly distributed conducting network on the surface. We also used the sol-gel ITO films to fabricate a simple liquid crystal display (LCD) device to demonstrate the excellent properties of our films.

Synthesis and characterization of transparent conductive zinc oxide thin films by sol-gel spin coating method

NASA Astrophysics Data System (ADS)

Winarski, David

Zinc oxide has been given much attention recently as it is promising for various semiconductor device applications. ZnO has a direct band gap of 3.3 eV, high exciton binding energy of 60 meV and can exist in various bulk powder and thin film forms for different applications. ZnO is naturally n-type with various structural defects, which sparks further investigation into the material properties. Although there are many potential applications for this ZnO, an overall lack of understand and control of intrinsic defects has proven difficult to obtain consistent, repeatable results. This work studies both synthesis and characterization of zinc oxide in an effort to produce high quality transparent conductive oxides. The sol-gel spin coating method was used to obtain highly transparent ZnO thin films with high UV absorbance. This research develops a new more consistent method for synthesis of these thin films, providing insight for maintaining quality control for each step in the procedure. A sol-gel spin coating technique is optimized, yielding highly transparent polycrystalline ZnO thin films with tunable electrical properties. Annealing treatment in hydrogen and zinc atmospheres is researched in an effort to increase electrical conductivity and better understand intrinsic properties of the material. These treatment have shown significant effects on the properties of ZnO. Characterization of doped and undoped ZnO synthesized by the sol-gel spin coating method was carried out using scanning electron microscopy, UV-Visible range absorbance, X-ray diffraction, and the Hall Effect. Treatment in hydrogen shows an overall decrease in the number of crystal phases and visible absorbance while zinc seems to have the opposite effect. The Hall Effect has shown that both annealing environments increase the n-type conductivity, yielding a ZnO thin film with a carrier concentration as high as 3.001 x 1021 cm-3.

Automation of the Reporting and Tracking Requirements of Architect-Engineering Type Contracts.

DTIC Science & Technology

1984-09-01

Electrical Eng 03 Oceano rahers 04 -- 10 Architect 05 Estimatcrs 06-- Urban Planners 07 Chemical Eng 08 -- Geologists 09--3 Sanitary Eng 10 -25 Civil Eng...geographic dispersicn of the activities, cc:tzal centers for information exchange should L idert iEd (newsletters, regional periodic meetizgs, sol r

A comparative study of the properties of five-layered Aurivillius oxides A2Bi4Ti5O18 (A = Ba, Pb, and Sr) synthesized by different wet chemical routes

NASA Astrophysics Data System (ADS)

Dubey, Shivangi; Subohi, Oroosa; Kurchania, Rajnish

2018-07-01

This paper reports the detailed study of the effect of different wet chemical synthesis routes (solution combustion, co-precipitation, and sol-gel route) on the microstructure, phase formation, dielectric, electrical, and ferroelectric properties of five-layered Aurivillius oxides: A2Bi4Ti5O18 (A = Ba, Pb, and Sr). Different synthesis parameters like the precursors used, synthesis temperature, and reaction time affects the morphology of the ceramics. Microstructure in turn influences the dielectric and ferroelectric properties. It was observed that the sol-gel-synthesized ceramics possess higher dielectric constant and remanent polarization, low dielectric loss due to lower conductivity in these samples as a result of higher density in these compounds as compared to those synthesized by other wet chemical synthesis routes such as solution combustion route and co-precipitation technique. The XRD data are used for phase analysis and surface morphology is studied using SEM images. Dielectric and electrical properties are investigated as a function of frequency and temperature.

Electrical, optical and structural properties of transparent conducting Al doped ZnO (AZO) deposited by sol-gel spin coating

NASA Astrophysics Data System (ADS)

Tonny, Kaniz Naila; Rafique, Rosaleena; Sharmin, Afrina; Bashar, Muhammad Shahriar; Mahmood, Zahid Hasan

2018-06-01

Al doped ZnO (AZO) films are fabricated by using sol-gel spin coating method and changes in electrical, optical and structural properties due to variation in film thickness is studied. AZO films provide c-axis orientation along the (002) plane and peak sharpness increased with film thickness is evident from XRD analysis. Conductivity (σ) of AZO films has increased from 2.34 (Siemens/cm) to 20156.27 (Siemens/cm) whereas sheet resistance (Rsh) decreases from 606300 (ohms/sq.) to 2.08 (ohm/sq.) with increase of film thickness from 296 nm to 1030 nm. Optical transmittance (T%) of AZO films is decreased from around 82% to 62% in the visible region. And grain size (D) of AZO thin films has been found to increase from 19.59 nm to 25.25 nm with increase of film thickness. Figure of Merit is also calculated for prepared sample of AZO. Among these four sample of AZO thin films, L-15 sample (having thickness in 895 nm) has provided highest figure of merit which is 5.49*10^-4 (Ω-1).

Influence of Sn doping on structural, optical and electrical properties of ZnO thin films prepared by cost effective sol-gel process.

PubMed

Vishwas, M; Narasimha Rao, K; Arjuna Gowda, K V; Chakradhar, R P S

2012-09-01

Tin (Sn) doped zinc oxide (ZnO) thin films were synthesized by sol-gel spin coating method using zinc acetate di-hydrate and tin chloride di-hydrate as the precursor materials. The films were deposited on glass and silicon substrates and annealed at different temperatures in air ambient. The agglomeration of grains was observed by the addition of Sn in ZnO film with an average grain size of 60 nm. The optical properties of the films were studied using UV-VIS-NIR spectrophotometer. The optical band gap energies were estimated at different concentrations of Sn. The MOS capacitors were fabricated using Sn doped ZnO films. The capacitance-voltage (C-V), dissipation vs. voltage (D-V) and current-voltage (I-V) characteristics were studied and the electrical resistivity and dielectric constant were estimated. The porosity and surface area of the films were increased with the doping of Sn which makes these films suitable for opto-electronic applications. Copyright © 2012 Elsevier B.V. All rights reserved.

Correlation between microstructure and electrical transport properties of La0.7(Ba1-xCax)0.3MnO3 (x = 0 and 0.03) synthesized by sol-gel

NASA Astrophysics Data System (ADS)

Kurniawan, Budhy; Winarsih, Suci; Imaduddin, Agung; Manaf, Azwar

2018-03-01

In this paper, we reported the correlation of structure, microstructure, and electrical transport properties of polycrystalline La0.7(Ba1-xCax)0.3MnO3 (x = 0 and 0.03). The materials were synthesized by sol-gel method. These materials have interesting electronic and magnetic properties which are heavily affected by the degree of crystallographic mismatch between the La and Mn sites. By tuning these sites, the double exchange (DE) and Coulomb interactions among Mn ions can be artificially controlled. La0.7Ba0.3MnO3 is one of the strong candidates for application because it has high magnetoresistance and magnetocaloric properties. Doped Ca to the La0.7Ba0.3MnO3 is aimed for reducing its transition temperature to near room temperature and increasing the magnetoresistance and magnetocaloric properties of this material. Jahn-Teller distortion can be linked to core-shell model with the result of percolation model.

Magnetic, ferroelectric and leakage current properties of gadolinium doped bismuth ferrite thin films by sol-gel method

NASA Astrophysics Data System (ADS)

Chen, Hone-Zern; Kao, Ming-Cheng; Young, San-Lin; Hwang, Jun-Dar; Chiang, Jung-Lung; Chen, Po-Yen

2015-05-01

Bi0.9Gd0.1FeO3 (BGFO) thin films were fabricated on Pt(111)/Ti/SiO2/Si(100) substrates by using the sol-gel technology. The effects of annealing temperature (400-700 °C) on microstructure and multiferroic properties of thin films were investigated. The X-ray diffraction analysis showed that the BGFO thin films had an orthorhombic structure. The thin films showed ferroelectric and ferromagnetic properties with remanent polarization (2Pr) of 10 μC/cm2, remnant magnetization (2Mr) of 2.4 emu/g and saturation magnetization (Ms) of 5.3 emu/g. A small leakage current density (J) was 4.64×10-8 A/cm2 under applied field 100 kV/cm. It was found that more than one conduction mechanism is involved in the electric field range used in these experiments. The leakage current mechanisms were controlled by Poole-Frenkel emission in the low electric field region and by Schottky emission from the Pt electrode in the high field region.

Turbulence, intermittency, and transport in the limiter shadow in LAPD and ET

NASA Astrophysics Data System (ADS)

Carter, Troy

2002-11-01

Turbulence in the scrape-off-layer (SOL) of tokamaks is often found to be intermittent, a tendency which has been attributed to the presence and transport of coherent structures (``blobs''). A recent theory [S.I. Krasheninnikov, shape Phys. Lett. A series 283, 368 (2001)] suggests that transport of these structures is controlled by nabla B and curvature drift driven polarization. I will present a study of turbulence and intermittency in limited discharges in the Large Plasma Device (LAPD) (where rotation may substitute for nabla B drift) and in the Electric Tokamak (ET) at UCLA. In LAPD, strongly intermittent turbulence in the 1-50 kHz range is observed localized to limiter produced gradients. A detailed study of these fluctuations will be presented, focusing on transport, dependencies on magnetic field, plasma density, and the presence of flows or rotation. A comparison with initial probe and imaging measurements of fluctuation characteristics in the SOL of the Electric Tokamak, in discharges with either an axisymmetric belt limiter or a toroidally localized limiter, will also be presented.

Bounce Rock Dimple

NASA Technical Reports Server (NTRS)

2004-01-01

This panoramic camera image shows the hole drilled by the Mars Exploration Rover Opportunity's rock abrasion tool into the rock dubbed 'Bounce' on Sol 65 of the rover's journey. The tool drilled about 7 millimeters (0.3 inches) into the rock and generated small piles of 'tailings' or rock dust around the central hole, which is about 4.5 centimeters (1.7 inches) across. The image from sol 66 of the mission was acquired using the panoramic camera's 430 nanometer filter.

Solution-processed Al-chelated gelatin for highly transparent non-volatile memory applications

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

Chang, Yu-Chi; Wang, Yeong-Her, E-mail: yhw@ee.ncku.edu.tw

2015-03-23

Using the biomaterial of Al-chelated gelatin (ACG) prepared by sol-gel method in the ITO/ACG/ITO structure, a highly transparent resistive random access memory (RRAM) was obtained. The transmittance of the fabricated device is approximately 83% at 550 nm while that of Al/gelatin/ITO is opaque. As to the ITO/gelatin/ITO RRAM, no resistive switching behavior can be seen. The ITO/ACG/ITO RRAM shows high ON/OFF current ratio (>10{sup 5}), low operation voltage, good uniformity, and retention characteristics at room temperature and 85 °C. The mechanism of the ACG-based memory devices is presented. The enhancement of these electrical properties can be attributed to the chelate effect ofmore » Al ions with gelatin. Results show that transparent ACG-based memory devices possess the potential for next-generation resistive memories and bio-electronic applications.« less

Processing and Characterization of Sol-Gel Cerium Oxide Microspheres

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

McClure, Zachary D.; Padilla Cintron, Cristina

Of interest to space exploration and power generation, Radioisotope Thermoelectric Generators (RTGs) can provide long-term power to remote electronic systems without the need for refueling or replacement. Plutonium-238 (Pu-238) remains one of the more promising materials for thermoelectric power generation due to its high power density, long half-life, and low gamma emissions. Traditional methods for processing Pu-238 include ball milling irregular precipitated powders before pressing and sintering into a dense pellet. The resulting submicron particulates of Pu-238 quickly accumulate and contaminate glove boxes. An alternative and dust-free method for Pu-238 processing is internal gelation via sol-gel techniques. Sol-gel methodology createsmore » monodisperse and uniform microspheres that can be packed and pressed into a pellet. For this study cerium oxide microspheres were produced as a surrogate to Pu-238. The similar electronic orbitals between cerium and plutonium make cerium an ideal choice for non-radioactive work. Before the microspheres can be sintered and pressed they must be washed to remove the processing oil and any unreacted substituents. An investigation was performed on the washing step to find an appropriate wash solution that reduced waste and flammable risk. Cerium oxide microspheres were processed, washed, and characterized to determine the effectiveness of the new wash solution.« less

A bulk micromachined lead zinconate titanate cantilever energy harvester with inter-digital IrO(x) electrodes.

PubMed

Park, Jongcheol; Park, Jae Yeong

2013-10-01

A piezoelectric vibration energy harvester with inter-digital IrO(x) electrode was developed by using silicon bulk micromachining technology. Most PZT cantilever based energy harvesters have utilized platinum electrode material. However, the PZT fatigue characteristics and adhesion/delamination problems caused by the platinum electrode might be serious problem in reliability of energy harvester. To address these problems, the iridium oxide was newly applied. The proposed energy harvester was comprised of bulk micromachined silicon cantilever with 800 x 1000 x 20 microm3, which having a silicon supporting membrane, sol-gel-spin coated Pb(Zr52, Ti48)O3 thin film, and sputtered inter-digitally shaped IrO(x) electrodes, and silicon inertial mass with 1000 x 1000 x 500 microm3 to adjust its resonant frequency. The fabricated energy harvester generated 1 microW of electrical power to 470 komega of load resistance and 1.4 V(peak-to-peak) from a vibration of 0.4 g at 1.475 kHz. The corresponding power density was 6.25 mW x cm(-3) x g(-2). As expected, its electrical failure was significantly improved.

Sensing response of copper phthalocyanine salt dispersed glass with organic vapours

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

Ridhi, R.; Sachdeva, Sheenam; Saini, G. S. S.

2016-05-06

Copper Phthalocyanine and other Metal Phthalocyanines are very flexible and tuned easily to modify their structural, spectroscopic, optical and electrical properties by either functionalizing them with various substituent groups or by replacing or adding a ligand to the central metal atom in the phthalocyanine ring and accordingly can be made sensitive and selective to various organic species or gaseous vapours. In the present work, we have dispersed Copper Phthalocyanine Salt (CuPcS) in sol-gel glass form using chemical route sol-gel method and studied its sensing mechanism with organic vapours like methanol and benzene and found that current increases onto their exposuremore » with vapours. A variation in the activation energies was also observed with exposure of vapours.« less

Sensing response of copper phthalocyanine salt dispersed glass with organic vapours

NASA Astrophysics Data System (ADS)

Ridhi, R.; Sachdeva, Sheenam; Saini, G. S. S.; Tripathi, S. K.

2016-05-01

Copper Phthalocyanine and other Metal Phthalocyanines are very flexible and tuned easily to modify their structural, spectroscopic, optical and electrical properties by either functionalizing them with various substituent groups or by replacing or adding a ligand to the central metal atom in the phthalocyanine ring and accordingly can be made sensitive and selective to various organic species or gaseous vapours. In the present work, we have dispersed Copper Phthalocyanine Salt (CuPcS) in sol-gel glass form using chemical route sol-gel method and studied its sensing mechanism with organic vapours like methanol and benzene and found that current increases onto their exposure with vapours. A variation in the activation energies was also observed with exposure of vapours.

Gyrokinetic particle simulation of a field reversed configuration

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

Fulton, D. P., E-mail: dfulton@uci.edu; Lau, C. K.; Holod, I.

2016-01-15

Gyrokinetic particle simulation of the field-reversed configuration (FRC) has been developed using the gyrokinetic toroidal code (GTC). The magnetohydrodynamic equilibrium is mapped from cylindrical coordinates to Boozer coordinates for the FRC core and scrape-off layer (SOL), respectively. A field-aligned mesh is constructed for solving self-consistent electric fields using a semi-spectral solver in a partial torus FRC geometry. This new simulation capability has been successfully verified and driftwave instability in the FRC has been studied using the gyrokinetic simulation for the first time. Initial GTC simulations find that in the FRC core, the ion-scale driftwave is stabilized by the large ionmore » gyroradius. In the SOL, the driftwave is unstable on both ion and electron scales.« less

Conductivity Probe Inserted in Martian Soil, Sol 46

NASA Technical Reports Server (NTRS)

2008-01-01

This image taken by the Surface Stereo Imager on NASA's Phoenix Mars Lander shows the lander's Thermal and Electrical Conductivity Probe (TECP), at the end of the Robotic Arm, on the 46th Martian day, or sol, of the mission (July 11, 2008).

The TECP is inserted at a site called Vestri, which was monitored several times over the course of the mission. The probe's measurements at this site yielded evidence that water was exchanged, daily and seasonally, between the soil and atmosphere.

The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is by NASA's Jet Propulsion Laboratory, Pasadena, Calif. Spacecraft development is by Lockheed Martin Space Systems, Denver.

Effects of addition of Ta and Y ions to InZnO thin film transistors by sol-gel process.

PubMed

Son, Dae-Ho; Kim, Dae-Hwan; Kim, Jung-Hye; Park, Si-Nae; Sung, Shi-Joon; Kang, Jin-Kyu

2013-06-01

We have investigated the effects of the addition of tantalum (Ta) and yttrium (Y) ions to InZnO thin film transistors (TFTs) using the sol-gel process. TaInZnO and YInZnO TFTs had significantly lower off current and higher on-to-off current ratio than InZnO TFTs. Ta and Y ions have strong affinity to oxygen and so suppress the formation of free electron carriers in thin films; they play an important role in enhancing the electrical characteristic due to their high oxygen bonding ability. The optimized TaInZnO and YInZnO TFTs showed high on/off ratio and low subthreshold swing.

Electronic transition and electrical transport properties of delafossite CuCr1-xMgxO2 (0 ≤ x ≤ 12%) films prepared by the sol-gel method: A composition dependence study

NASA Astrophysics Data System (ADS)

Han, M. J.; Duan, Z. H.; Zhang, J. Z.; Zhang, S.; Li, Y. W.; Hu, Z. G.; Chu, J. H.

2013-10-01

Highly transparent CuCr1-xMgxO2 (0 ≤ x ≤ 12%) films were prepared on (001) sapphire substrates by sol-gel method. The microstructure, phonon modes, optical band gap, and electrical transport properties have been systematically discussed. It was found that Mg-doping improved the crystal quality and enhanced the (00l) preferred orientation. The spectral transmittance of films approaches about 70%-75% in the visible-near-infrared wavelength region. With increasing Mg-composition, the optical band gap first declines and climbs up due to the band gap renormalization and Burstein-Moss effect. The direct and indirect band gaps of CuCr0.94Mg0.06O2 film are 3.00 and 2.56 eV, respectively. In addition, it shows a crossover from the thermal activation behavior to that of three-dimensional variable range hopping from temperature-dependent electrical conductivity. The crossover temperature decreases with increasing Mg-doping composition, which can be ascribed to the change of spin-charge coupling between the hole and the local spin at Cr site. It should be noted that the electrical conductivity of CuCr1-xMgxO2 films becomes larger with increasing x value. The highest electrical conductivity of 3.85 S cm-1 at room temperature for x = 12% is four-order magnitude larger than that (8.81 × 10-4 S cm-1) for pure CuCrO2 film. The high spectral transmittance and larger conductivity indicate that Mg-doped CuCrO2 films are promising for optoelectronic device applications.

A Lion of a Stone

NASA Technical Reports Server (NTRS)

2004-01-01

This approximate true-color image of the rock called 'Lion Stone' was acquired by the Mars Exploration Rover Opportunity's panoramic camera on sol 104 (May 9, 2004). The rock stands about 10 centimeters tall (about 4 inches) and is about 30 centimeters long (12 inches). Plans for the coming sols include investigating the rock with the spectrometers on the rover's instrument arm.

This image was generated using the camera's L2 (750-nanometer), L5 (530-nanometer) and L6 (480-nanometer) filters.

Phoenix Conductivity Probe with Shadow and Toothmark

NASA Technical Reports Server (NTRS)

2008-01-01

NASA's Phoenix Mars Lander inserted the four needles of its thermal and conductivity probe into Martian soil during the 98th Martian day, or sol, of the mission and left it in place until Sol 99 (Sept. 4, 2008).

The Robotic Arm Camera on Phoenix took this image on the morning of Sol 99 after the probe was lifted away from the soil. The imprint left by the insertion is visible below the probe, and a shadow showing the probe's four needles is cast on a rock to the left.

The thermal and conductivity probe measures how fast heat and electricity move from one needle to an adjacent one through the soil or air between the needles. Conductivity readings can be indicators about water vapor, water ice and liquid water.

The probe is part of Phoenix's Microscopy, Electrochemistry and Conductivity suite of instruments.

The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is by NASA's Jet Propulsion Laboratory, Pasadena, Calif. Spacecraft development is by Lockheed Martin Space Systems, Denver.

Kinetic studies of divertor heat fluxes in Alcator C-Mod

NASA Astrophysics Data System (ADS)

Pankin, A. Y.; Bateman, G.; Kritz, A. H.; Rafiq, T.; Park, G. Y.; Chang, C. S.; Brunner, D.; Hughes, J. W.; Labombard, B.; Terry, J.

2010-11-01

The kinetic XGC0 code [C.S. Chang et al, Phys. Plasmas 11 (2004) 2649] is used to model the H- mode pedestal and SOL regions in Alcator C-Mod discharges. The self-consistent simulations in this study include kinetic neoclassical physics and anomalous transport models along with the ExB flow shear effects. The heat fluxes on the divertor plates are computed and the fluxes to the outer plate are compared with experimental observations. The dynamics of the radial electric field near the separatrix and in the SOL region are computed with the XGC0 code, and the effect of the anomalous transport on the heat fluxes in the SOL region is investigated. In particular, the particle and thermal diffusivities obtained in the analysis mode are compared with predictions from the theory-based anomalous transport models such as MMM95 [G. Bateman et al, Phys. Plasmas 5 (1998) 1793] and DRIBM [T. Rafiq et al, to appear in Phys. Plasmas (2010)]. It is found that there is a notable pinch effect in the inner separatrix region. Possible physical mechanisms for the particle and thermal pinches are discussed.

Circadian force and EMG activity in hindlimb muscles of rhesus monkeys

NASA Technical Reports Server (NTRS)

Hodgson, J. A.; Wichayanuparp, S.; Recktenwald, M. R.; Roy, R. R.; McCall, G.; Day, M. K.; Washburn, D.; Fanton, J. W.; Kozlovskaya, I.; Edgerton, V. R.;

Highly flexible, nonflammable and free-standing SiC nanowire paper

NASA Astrophysics Data System (ADS)

Chen, Jianjun; Liao, Xin; Wang, Mingming; Liu, Zhaoxiang; Zhang, Judong; Ding, Lijuan; Gao, Li; Li, Ye

2015-03-01

Flexible paper-like semiconductor nanowire materials are expected to meet the criteria for some emerging applications, such as components of flexible solar cells, electrical batteries, supercapacitors, nanocomposites, bendable or wearable electronic or optoelectronic components, and so on. As a new generation of wide-bandgap semiconductors and reinforcements in composites, SiC nanowires have advantages in power electronic applications and nanofiber reinforced ceramic composites. Herein, free-standing SiC nanowire paper consisting of ultralong single-crystalline SiC nanowires was prepared through a facile vacuum filtration approach. The ultralong SiC nanowires were synthesized by a sol-gel and carbothermal reduction method. The flexible paper composed of SiC nanowires is ~100 nm in width and up to several hundreds of micrometers in length. The nanowires are intertwisted with each other to form a three-dimensional network-like structure. SiC nanowire paper exhibits high flexibility and strong mechanical stability. The refractory performance and thermal stability of SiC nanowire paper were also investigated. The paper not only exhibits excellent nonflammability in fire, but also remains well preserved without visible damage when it is heated in an electric oven at a high temperature (1000 °C) for 3 h. With its high flexibility, excellent nonflammability, and high thermal stability, the free-standing SiC nanowire paper may have the potential to improve the ablation resistance of high temperature ceramic composites.Flexible paper-like semiconductor nanowire materials are expected to meet the criteria for some emerging applications, such as components of flexible solar cells, electrical batteries, supercapacitors, nanocomposites, bendable or wearable electronic or optoelectronic components, and so on. As a new generation of wide-bandgap semiconductors and reinforcements in composites, SiC nanowires have advantages in power electronic applications and nanofiber reinforced ceramic composites. Herein, free-standing SiC nanowire paper consisting of ultralong single-crystalline SiC nanowires was prepared through a facile vacuum filtration approach. The ultralong SiC nanowires were synthesized by a sol-gel and carbothermal reduction method. The flexible paper composed of SiC nanowires is ~100 nm in width and up to several hundreds of micrometers in length. The nanowires are intertwisted with each other to form a three-dimensional network-like structure. SiC nanowire paper exhibits high flexibility and strong mechanical stability. The refractory performance and thermal stability of SiC nanowire paper were also investigated. The paper not only exhibits excellent nonflammability in fire, but also remains well preserved without visible damage when it is heated in an electric oven at a high temperature (1000 °C) for 3 h. With its high flexibility, excellent nonflammability, and high thermal stability, the free-standing SiC nanowire paper may have the potential to improve the ablation resistance of high temperature ceramic composites. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr00776c

Effects of muscle activation on shear between human soleus and gastrocnemius muscles.

PubMed

Finni, T; Cronin, N J; Mayfield, D; Lichtwark, G A; Cresswell, A G

2017-01-01

Lateral connections between muscles provide pathways for myofascial force transmission. To elucidate whether these pathways have functional roles in vivo, we examined whether activation could alter the shear between the soleus (SOL) and lateral gastrocnemius (LG) muscles. We hypothesized that selective activation of LG would decrease the stretch-induced shear between LG and SOL. Eleven volunteers underwent a series of knee joint manipulations where plantar flexion force, LG, and SOL muscle fascicle lengths and relative displacement of aponeuroses between the muscles were obtained. Data during a passive full range of motion were recorded, followed by 20° knee extension stretches in both passive conditions and with selective electrical stimulation of LG. During active stretch, plantar flexion force was 22% greater (P < 0.05) and relative displacement of aponeuroses was smaller than during passive stretch (P < 0.05). Soleus fascicle length changes did not differ between passive and active stretches but LG fascicles stretched less in the active than passive condition when the stretch began at angles of 70° and 90° of knee flexion (P < 0.05). The activity-induced decrease in the relative displacement of SOL and LG suggests stronger (stiffer) connectivity between the two muscles, at least at flexed knee joint angles, which may serve to facilitate myofascial force transmission. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Preparation of fullerene/glass composites

DOEpatents

Mattes, Benjamin R.; McBranch, Duncan W.; Robinson, Jeanne M.; Koskelo, Aaron C.; Love, Steven P.

1995-01-01

Synthesis of fullerene/glass composites. A direct method for preparing solid solutions of C.sub.60 in silicon dioxide (SiO.sub.2) glass matrices by means of sol-gel chemistry is described. In order to produce highly concentrated fullerene-sol-gel-composites it is necessary to increase the solubility of these "guests" in a delivery solvent which is compatible with the starter sol (receiving solvent). Sonication results in aggregate disruption by treatment with high frequency sound waves, thereby accelerating the rate of hydrolysis of the alkoxide precursor, and the solution process for the C.sub.60. Depending upon the preparative procedure, C.sub.60 dispersed within the glass matrix as microcrystalline domains, or dispersed as true molecular solutions of C.sub.60 in a solid glass matrix, is generated by the present method.

Preparation of fullerene/glass composites

DOEpatents

Mattes, B.R.; McBranch, D.W.; Robinson, J.M.; Koskelo, A.C.; Love, S.P.

1995-05-30

Synthesis of fullerene/glass composites is described. A direct method for preparing solid solutions of C{sub 60} in silicon dioxide (SiO{sub 2}) glass matrices by means of sol-gel chemistry is described. In order to produce highly concentrated fullerene-sol-gel-composites it is necessary to increase the solubility of these ``guests`` in a delivery solvent which is compatible with the starter sol (receiving solvent). Sonication results in aggregate disruption by treatment with high frequency sound waves, thereby accelerating the rate of hydrolysis of the alkoxide precursor, and the solution process for the C{sub 60}. Depending upon the preparative procedure, C{sub 60} dispersed within the glass matrix as microcrystalline domains, or dispersed as true molecular solutions of C{sub 60} in a solid glass matrix, is generated by the present method.

Quasi-distributed sol-gel coated fiber optic oxygen sensing probe

NASA Astrophysics Data System (ADS)

Zolkapli, Maizatul; Saharudin, Suhairi; Herman, Sukreen Hana; Abdullah, Wan Fazlida Hanim

2018-03-01

In the field of aquaculture, optical sensor technology is beginning to provide alternatives to the conventional electrical sensor. Hence, the development and characterization of a multipoint quasi-distributed optical fiber sensor for oxygen measurement is reported. The system is based on 1 mm core diameter plastic optical fiber where sections of cladding have been removed and replaced with three metal complexes sol-gel films to form sensing points. The sensing locations utilize luminophores that have emission peaks at 385 nm, 405 nm and 465 nm which associated with each of the sensing points. Interrogation of the optical sensor system is through a fiber optic spectrometer incorporating narrow bandpass emission optical filter. The sensors showed comparable sensitivity and repeatability, as well as fast response and recovery towards oxygen.

Recent progress towards a quantitative description of filamentary SOL transport

NASA Astrophysics Data System (ADS)

Carralero, D.; Siccinio, M.; Komm, M.; Artene, S. A.; D'Isa, F. A.; Adamek, J.; Aho-Mantila, L.; Birkenmeier, G.; Brix, M.; Fuchert, G.; Groth, M.; Lunt, T.; Manz, P.; Madsen, J.; Marsen, S.; Müller, H. W.; Stroth, U.; Sun, H. J.; Vianello, N.; Wischmeier, M.; Wolfrum, E.; ASDEX Upgrade Team; COMPASS Team; Contributors, JET; The EUROfusion MST Team

2017-05-01

A summary of recent results on filamentary transport, mostly obtained with the ASDEX-Upgrade tokamak (AUG), is presented and discussed in an attempt to produce a coherent picture of scrape-off layer (SOL) filamentary transport. A clear correlation is found between L-mode density shoulder formation in the outer midplane and a transition between the sheath-limited and the inertial filamentary regimes. Divertor collisionality is found to be the parameter triggering the transition. A clear reduction of the ion temperature takes place in the far SOL after the transition, both for the background and the filaments. This coincides with a strong variation of the ion temperature distribution, which deviates from Gaussianity and becomes dominated by a strong peak below 5 eV. The filament transition mechanism triggered by a critical value of collisionality seems to be generally applicable to inter-ELM H-mode plasmas, although a secondary threshold related to deuterium fueling is observed. EMC3-EIRENE simulations of neutral dynamics show that an ionization front near the main chamber wall is formed after the shoulder formation. Finally, a clear increase of SOL opacity to neutrals is observed, associated with the shoulder formation. A common SOL transport framework is proposed to account for all these results, and their potential implications for future generation devices are discussed.

SolEST database: a "one-stop shop" approach to the study of Solanaceae transcriptomes.

PubMed

D'Agostino, Nunzio; Traini, Alessandra; Frusciante, Luigi; Chiusano, Maria Luisa

2009-11-30

Since no genome sequences of solanaceous plants have yet been completed, expressed sequence tag (EST) collections represent a reliable tool for broad sampling of Solanaceae transcriptomes, an attractive route for understanding Solanaceae genome functionality and a powerful reference for the structural annotation of emerging Solanaceae genome sequences. We describe the SolEST database http://biosrv.cab.unina.it/solestdb which integrates different EST datasets from both cultivated and wild Solanaceae species and from two species of the genus Coffea. Background as well as processed data contained in the database, extensively linked to external related resources, represent an invaluable source of information for these plant families. Two novel features differentiate SolEST from other resources: i) the option of accessing and then visualizing Solanaceae EST/TC alignments along the emerging tomato and potato genome sequences; ii) the opportunity to compare different Solanaceae assemblies generated by diverse research groups in the attempt to address a common complaint in the SOL community. Different databases have been established worldwide for collecting Solanaceae ESTs and are related in concept, content and utility to the one presented herein. However, the SolEST database has several distinguishing features that make it appealing for the research community and facilitates a "one-stop shop" for the study of Solanaceae transcriptomes.

Correlation of the oxidation state of cerium in sol-gel glasses as a function of thermal treatment via optical spectroscopy and XANES studies.

PubMed

Assefa, Zerihun; Haire, R G; Caulder, D L; Shuh, D K

2004-07-01

Sol-gel glass matrices containing lanthanides have numerous technological applications and their formation involves several chemical facets. In the case of cerium, its ability to exist in two different oxidation states or in mixed valence state provides additional complexities for the sol-gel process. The oxidation state of cerium present during different facets of preparation of sol-gel glasses, and also as a function of the starting oxidation state of cerium added, were studied both by optical spectroscopy and X-ray absorption near-edge structures (XANES). The findings acquired by each approach were compared. The primary focus was on the redox chemistries associated with sample preparation, gelation, and thermal treatment. When Ce3+ is introduced into the starting sols, the trivalent state normally prevails in the wet and room temperature-dried gels. Heating in air at >100 degrees C can generate a light yellow coloration with partial oxidation to the tetravalent state. Above 200 degrees C and up to approximately 1000 degrees C, cerium is oxidized to its tetravalent state. In contrast, when tetravalent cerium is introduced into the sol, both the wet and room temperature-dried gels lose the yellow-brown color of the initial ceric ammonium nitrate solution. When the sol-gel is heated to 110 degrees C it turns yellowish as the cerium tends to be re-oxidized. The yellow color is believed to represent the effect of oxidation and oligomerization of the cerium-silanol units in the matrix. The luminescence properties are also affected by these changes, the details of which are reported herein.

Social Values for Ecosystem Services, version 3.0 (SolVES 3.0): documentation and user manual

USGS Publications Warehouse

Sherrouse, Ben C.; Semmens, Darius J.

2015-01-01

The geographic information system (GIS) tool, Social Values for Ecosystem Services (SolVES), was developed to incorporate quantified and spatially explicit measures of social values into ecosystem service assessments. SolVES 3.0 continues to extend the functionality of SolVES, which was designed to assess, map, and quantify the social values of ecosystem services. Social values—the perceived, nonmarket values the public ascribes to ecosystem services, particularly cultural services, such as aesthetics and recreation—can be evaluated for various stakeholder groups. These groups are distinguishable by their attitudes and preferences regarding public uses, such as motorized recreation and logging. As with previous versions, SolVES 3.0 derives a quantitative 10-point, social-values metric—the value index—from a combination of spatial and nonspatial responses to public value and preference surveys. The tool also calculates metrics characterizing the underlying environment, such as average distance to water and dominant landcover. SolVES 3.0 is integrated with Maxent maximum entropy modeling software to generate more complete social-value maps and offer robust statistical models describing the relationship between the value index and explanatory environmental variables. A model’s goodness of fit to a primary study area and its potential performance in transferring social values to similar areas using value-transfer methodology can be evaluated. SolVES 3.0 provides an improved public-domain tool for decision makers and researchers to evaluate the social values of ecosystem services and to facilitate discussions among diverse stakeholders regarding the tradeoffs among ecosystem services in a variety of physical and social contexts ranging from forest and rangeland to coastal and marine.

Comparing nanostructured hydroxyapatite coating on AZ91 alloy samples via sol-gel and electrophoretic deposition for biomedical applications.

PubMed

Rojaee, Ramin; Fathi, Mohammadhossein; Raeissi, Keyvan

2014-12-01

Magnesium is one of the most critical elements in hard tissues regeneration and therefore causes speeding up the restoration of harmed bones, while high deterioration rate of magnesium in body fluid restricts it to be used as biodegradable implants. Alloying magnesium with some relatively nobler metals such as aluminium, zinc, rare earth elements, magnesium-bioceramics composites, and surface modification techniques are some of the routes to control magnesium corrosion rate. In this study AZ91 magnesium alloy had been coated by nanostructured hydroxyapatite via sol-gel dip coating and electrophoretical methods to survey the final barricade properties of the obtained coatings. In order to perform electrophoretic coating, powders were prepared by sol-gel method, and then the powders deposited on substrates utilizing direct current electricity. Zeta potentials of the electrophoresis suspensions were measured to determine a best mode for good quality coatings. Transmission Electron Microscopy (TEM), and Scanning Electron Microscopy (SEM) were used to confirm nanoscale dimension, and the uniformity of the nanostructured hydroxyapatite coating, respectively. Fourier Transform-Infrared and X-ray diffraction analysis were utilized for functional group and phase structure evaluation of the prepared coatings, correspondingly. Electrochemical corrosion tests were performed in SBF at 37±1 (°)C which revealed considerable increase in corrosion protection resistivity and corrosion current density for electrophoretic coated specimens versus sol-gel coated specimens. Results showed that both sol-gel and electrophoretical techniques seem to be suitable to coat magnesium alloys for biomedical applications but electrophoretic coating technique is a better choice due to the more homogeneity and more crystalline structure of the coating.

Social values for ecosystem services (SolVES): Documentation and user manual, version 2.0

USGS Publications Warehouse

Sherrouse, Benson C.; Semmens, Darius J.

2012-01-01

In response to the need for incorporating quantified and spatially explicit measures of social values into ecosystem services assessments, the Rocky Mountain Geographic Science Center (RMGSC), in collaboration with Colorado State University, developed a geographic information system (GIS) application, Social Values for Ecosystem Services (SolVES). With version 2.0 (SolVES 2.0), RMGSC has improved and extended the functionality of SolVES, which was designed to assess, map, and quantify the perceived social values of ecosystem services. Social values such as aesthetics, biodiversity, and recreation can be evaluated for various stakeholder groups as distinguished by their attitudes and preferences regarding public uses, such as motorized recreation and logging. As with the previous version, SolVES 2.0 derives a quantitative, 10-point, social-values metric, the Value Index, from a combination of spatial and nonspatial responses to public attitude and preference surveys and calculates metrics characterizing the underlying environment, such as average distance to water and dominant landcover. Additionally, SolVES 2.0 integrates Maxent maximum entropy modeling software to generate more complete social value maps and to produce robust statistical models describing the relationship between the social values maps and explanatory environmental variables. The performance of these models can be evaluated for a primary study area, as well as for similar areas where primary survey data are not available but where social value mapping could potentially be completed using value-transfer methodology. SolVES 2.0 also introduces the flexibility for users to define their own social values and public uses, model any number and type of environmental variable, and modify the spatial resolution of analysis. With these enhancements, SolVES 2.0 provides an improved public domain tool for decisionmakers and researchers to evaluate the social values of ecosystem services and to facilitate discussions among diverse stakeholders regarding the tradeoffs among different ecosystem services in a variety of physical and social contexts ranging from forest and rangeland to coastal and marine.

Enhancement on crystallinity property of low annealed PbTiO3 thin films for metal-insulator-metal capacitor

NASA Astrophysics Data System (ADS)

Nurbaya, Z.; Wahid, M. H.; Rozana, M. D.; Alrokayan, S. A. H.; Khan, H. A.; Rusop, M.

2018-05-01

This study presents the investigation on crystallinity property of PbTiO3 thin films towards metal-insulator-metal capacitor device fabrication. The preparation of the thin films utilizes sol-gel spin coating method with low annealing temperature effect. Hence, structural and electrical characterization is brought to justify the thin films consistency.

Influence of transcutaneous electrical nerve stimulation conditions on disynaptic reciprocal Ia inhibition and presynaptic inhibition in healthy adults.

PubMed

Takeda, Kazuya; Tanabe, Shigeo; Koyama, Soichiro; Ushiroyama, Kosuke; Naoi, Yuki; Motoya, Ikuo; Sakurai, Hiroaki; Kanada, Yoshikiyo

2017-03-01

This study investigated the influence of stimulus conditions of transcutaneous electrical nerve stimulation (TENS) on disynaptic reciprocal Ia inhibition (RI) and presynaptic inhibition (D1 inhibition) in healthy adults. Eight healthy participants received TENS (stimulus frequencies of 50, 100, and 200 Hz) over the deep peroneal nerve and tibialis anterior (TA) muscle in the resting condition for 30 min. At pre- and post-intervention, the RI from the TA to the soleus (SOL) and D1 inhibition of the SOL alpha motor neuron were assessed by evoked electromyography. The results showed that RI was not changed by TENS at any stimulus frequency condition. Conversely, D1 inhibition was significantly changed by TENS regardless of the stimulus frequency. The present results and previous studies pertaining to RI suggest that the resting condition might strongly influence the lack of pre- vs. post-intervention change in the RI. Regarding the D1 inhibition, the present results suggest that the effect of TENS might be caused by post-tetanic potentiation. The knowledge gained from the present study might contribute to a better understanding of fundamental studies of TENS in healthy adults and its clinical application for stroke survivors.

Characterization and frequency-thermal response of electrical properties of Cu nanoferrite prepared by sol-gel method

NASA Astrophysics Data System (ADS)

Moghadasi, Fatemeh S.; Daadmehr, Vahid; Kashfi, Monire

2016-10-01

In this paper, we have synthesized copper ferrite nanocrystals using sol-gel method. X-ray diffraction (XRD) analysis confirms that the ferrite has cubic spinal structure and shows Jahn-Teller effect. Also, scan electron microscope (SEM) image demonstrates that grains are nano size order. We showed that the dielectric properties are compatible with the Maxwell-Wagner model and phenomenological Koop's theory. Loss tangent and conductivity of the ferrite have been measured to have small values of 2.4 and 2×10-7 S/m, respectively at room temperature and at 12 Hz. Conductivity has been investigated in terms of localized hopping mechanism and good obedience of Jonscher's law was observed. Variation of activation energy was studied and showed a transition temperature of 443 °K. The electrical modulus shows relaxation of interfacial polarization with relaxation time of 0.318 ms at 24 °C and 15.9 μs at 72 °C. In Impedance spectroscopy, we observed the effects of grain and grain boundary. By increasing temperature, capacity and conduction would increase which show easier polarization process and a semiconducting behavior. Also, relaxation times are shifted to smaller values to represent increasing the electrons mobility.

Optical and structural properties of Al-doped ZnO thin films by sol gel process.

PubMed

Jun, Min-Chul; Koh, Jung-Hyuk

2013-05-01

Transparent conducting oxide (TCO) materials with high transmittance and good electrical conductivity have been attracted much attention due to the development of electronic display and devices such as organic light emitting diodes (OLEDs), and dye-sensitized solar cells (DSSCs). Aluminum doped zinc oxide thin films (AZO) have been well known for their use as TCO materials due to its stability, cost-effectiveness, good optical transmittance and electrical properties. Especially, AZO thin film, which have low resistivity of 2-4 x 10(-4) omega x cm which is similar to that of ITO films with wide band gap semiconductors. The AZO thin films were deposited on glass substrates by sol-gel spin-coating process. As a starting material, zinc acetate dihydrate (Zn(CH3COO)2 x 2H2O) and aluminum chloride hexahydrate (AlCl3 6H2O) were used. 2-methoxyethanol and monoethanolamine (MEA) were used as solvent and stabilizer, respectively. After deposited, the films were preheated at 300 degrees C on a hotplate and post-heated at 650 degrees C for 1.5 hrs in the furnace. We have studied the structural and optical properties as a function of Al concentration (0-2.5 mol.%).

Electrical Investigation of Nanostructured Fe2O3/p-Si Heterojunction Diode Fabricated Using the Sol-Gel Technique

NASA Astrophysics Data System (ADS)

Mansour, Shehab A.; Ibrahim, Mervat M.

2017-11-01

Iron oxide (α-Fe2O3) nanocrystals have been synthesized via the sol-gel technique. The structural and morphological features of these nanocrystals were studied using x-ray diffraction, Fourier transform-infrared spectroscopy and transmission electron microscopy. Colloidal solution of synthesized α-Fe2O3 (hematite) was spin-coated onto a single-crystal p-type silicon (p-Si) wafer to fabricate a heterojunction diode with Mansourconfiguration Ag/Fe2O3/p-Si/Al. This diode was electrically characterized at room temperature using current-voltage (I-V) characteristics in the voltage range from -9 V to +9 V. The fabricated diode showed a good rectification behavior with a rectification factor 1.115 × 102 at 6 V. The junction parameters such as ideality factor, barrier height, series resistance and shunt resistance are determined using conventional I-V characteristics. For low forward voltage, the conduction mechanism is dominated by the defect-assisted tunneling process with conventional electron-hole recombination. However, at higher voltage, I-V ohmic and space charge-limited current conduction was became less effective with the contribution of the trapped-charge-limited current at the highest voltage range.

Effect of Organic Blocking Layer on the Energy Storage Characteristics of High-Permittivity Sol-Gel Thin Film Based on Neat 2-Cyanoethyltrimethoxysilane

NASA Astrophysics Data System (ADS)

Kim, Yunsang; Kathaperumal, Mohanalingam; Pan, Ming-Jen; Perry, Joseph

2014-03-01

Organic-inorganic hybrid sol-gel materials with polar groups that can undergo reorientational polarization provide a potential route to dielectric materials for energy storage. We have investigated the influence of nanoscale polymeric layer on dielectric and energy storage properties of 2-cyanoethyltrimethoxysilane (CNETMS) films. Two polymeric materials, fluoropolymer (CYTOP) and poly(p-phenylene oxide, PPO), are examined as potential materials to control charge injection from electrical contacts into CNETMS films by means of a potential barrier, whose width and height are defined by thickness and permittivity. Blocking layers ranging from 20 nm to 200 nm were deposited on CNETMS films by spin casting and subjected to thermal treatment. Polarization-electric field measurements show 30% increase in extractable energy density with PPO/CNETMS bilayers, relative to CNETMS alone, due to improved breakdown strength. Conduction current of the bilayers indicate that onset of charge conduction at high field is much delayed, which can be translated into effective suppression of charge injection and probability of breakdown events. The results will be discussed in regards to film morphology, field partitioning, width and height of potential barrier, charge trapping and loss of bilayers.

Interfacial structure and electrical properties of ultrathin HfO2 dielectric films on Si substrates by surface sol-gel method

NASA Astrophysics Data System (ADS)

Gong, You-Pin; Li, Ai-Dong; Qian, Xu; Zhao, Chao; Wu, Di

2009-01-01

Ultrathin HfO2 films with about ~3 nm thickness were deposited on n-type (1 0 0) silicon substrates using hafnium chloride (HfCl4) source by the surface sol-gel method and post-deposition annealing (PDA). The interfacial structure and electrical properties of ultrathin HfO2 films were investigated. The HfO2 films show amorphous structures and smooth surface morphologies with a very thin interfacial oxide layer of ~0.5 nm and small surface roughness (~0.45 nm). The 500 °C PDA treatment forms stronger Hf-O bonds, leading to passivated traps, and the interfacial layer is mainly Hf silicate (HfxSiyOz). Equivalent oxide thickness of around 0.84 nm of HfO2/Si has been obtained with a leakage current density of 0.7 A cm-2 at Vfb + 1 V after 500 °C PDA. It was found that the current conduction mechanism of HfO2/Si varied from Schottky-Richardson emission to Fowler-Nordheim tunnelling at an applied higher positive voltage due to the activated partial traps remaining in the ultrathin HfO2 films.

Study of nanoparticles TiO2 thin films on p-type silicon substrate using different alcoholic solvents

NASA Astrophysics Data System (ADS)

Muaz, A. K. M.; Hashim, U.; Arshad, M. K. Md.; Ruslinda, A. R.; Ayub, R. M.; Gopinath, Subash C. B.; Voon, C. H.; Liu, Wei-Wen; Foo, K. L.

2016-07-01

In this paper, sol-gel method spin coating technique is adopted to prepare nanoparticles titanium dioxide (TiO2) thin films. The prepared TiO2 sol was synthesized using titanium butoxide act as a precursor and subjected to deposited on the p-type silicon oxide (p-SiO2) and glass slide substrates under room temperature. The effect of different alcoholic solvents of methanol and ethanol on the structural, morphological, optical and electrical properties were systematically investigated. The coated TiO2 thin films were annealed in furnace at 773 K for 1 h. The structural properties of the TiO2 films were examined with X-ray Diffraction (XRD). From the XRD analysis, both solvents showing good crystallinity with anatase phase were the predominant structure. Atomic Force Microscopy (AFM) was employed to study the morphological of the thin films. The optical properties were investigated by Ultraviolet-visible (UV-Vis) spectroscopy were found that ethanol as a solvent give a higher optical transmittance if compare to the methanol solvent. The electrical properties of the nanoparticles TiO2 thin films were measured using two-point-probe technique.

Internal energy transfer phenomenon and light-emission properties of γ-LiAlO2 phosphor doped with Mn2+

NASA Astrophysics Data System (ADS)

Wang, Bai-Bin; Chang, Chi-Fen; Yang, Wein-Duo

2013-07-01

γ-LiAlO2:Mn2+ phosphor was synthesized using the cellulose-citric acid sol-gel method, and its light emission and energy transfer properties were investigated. Excitation and emission spectrum analysis revealed a decrease in intensity of the spectrum as the amount of Mn2+ doping increased. Blasse's equation determined the maximum distance for energy transfer between Mn2+ ions as 4.3142 nm. Dexter's theory verifies that the mechanism of energy transfer between Mn2+ ions conforms to an electric dipole and electric quadrupole interaction.

An application of Social Values for Ecosystem Services (SolVES) to three national forests in Colorado and Wyoming

USGS Publications Warehouse

Sherrouse, Benson C.; Semmens, Darius J.; Clement, Jessica M.

2014-01-01

Despite widespread recognition that social-value information is needed to inform stakeholders and decision makers regarding trade-offs in environmental management, it too often remains absent from ecosystem service assessments. Although quantitative indicators of social values need to be explicitly accounted for in the decision-making process, they need not be monetary. Ongoing efforts to map such values demonstrate how they can also be made spatially explicit and relatable to underlying ecological information. We originally developed Social Values for Ecosystem Services (SolVES) as a tool to assess, map, and quantify nonmarket values perceived by various groups of ecosystem stakeholders. With SolVES 2.0 we have extended the functionality by integrating SolVES with Maxent maximum entropy modeling software to generate more complete social-value maps from available value and preference survey data and to produce more robust models describing the relationship between social values and ecosystems. The current study has two objectives: (1) evaluate how effectively the value index, a quantitative, nonmonetary social-value indicator calculated by SolVES, reproduces results from more common statistical methods of social-survey data analysis and (2) examine how the spatial results produced by SolVES provide additional information that could be used by managers and stakeholders to better understand more complex relationships among stakeholder values, attitudes, and preferences. To achieve these objectives, we applied SolVES to value and preference survey data collected for three national forests, the Pike and San Isabel in Colorado and the Bridger–Teton and the Shoshone in Wyoming. Value index results were generally consistent with results found through more common statistical analyses of the survey data such as frequency, discriminant function, and correlation analyses. In addition, spatial analysis of the social-value maps produced by SolVES provided information that was useful for explaining relationships between stakeholder values and forest uses. Our results suggest that SolVES can effectively reproduce information derived from traditional statistical analyses while adding spatially explicit, social-value information that can contribute to integrated resource assessment, planning, and management of forests and other ecosystems.

Plasmon mediated cathodic photocurrent generation in sol-gel synthesized doped SrTiO{sub 3} nanofilms

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

Sugavaneshwar, Ramu Pasupathi, E-mail: r.p.sugavaneshwar@nims.go.jp, E-mail: NAGAO.Tadaaki@nims.go.jp; Chen, Kai; Lakshminarayana, Gandham

2015-11-01

Thin films of SrTiO{sub 3} (STO) and Rh-doped SrTiO{sub 3} (Rh-STO) were synthesized by sol-gel method and loaded with Ag nanoparticles. Pristine STO films exhibited anodic photocurrent while Rh-STO exhibited cathodic photocurrent. An enhancement in the overall cathodic photocurrent is observed with Ag nanoparticle loading and an additional enhancement in the visible light range is seen from the incident photon-to-current efficiency spectrum due to synergetic effect of Rh doping and Ag loading in STO.

Modulation of spinal inhibitory reflexes depends on the frequency of transcutaneous electrical nerve stimulation in spastic stroke survivors.

PubMed

Koyama, Soichiro; Tanabe, Shigeo; Takeda, Kazuya; Sakurai, Hiroaki; Kanada, Yoshikiyo

2016-03-01

Neurophysiological studies in healthy subjects suggest that increased spinal inhibitory reflexes from the tibialis anterior (TA) muscle to the soleus (SOL) muscle might contribute to decreased spasticity. While 50 Hz is an effective frequency for transcutaneous electrical nerve stimulation (TENS) in healthy subjects, in stroke survivors, the effects of TENS on spinal reflex circuits and its appropriate frequency are not well known. We examined the effects of different frequencies of TENS on spinal inhibitory reflexes from the TA to SOL muscle in stroke survivors. Twenty chronic stroke survivors with ankle plantar flexor spasticity received 50-, 100-, or 200-Hz TENS over the deep peroneal nerve (DPN) of the affected lower limb for 30 min. Before and immediately after TENS, reciprocal Ia inhibition (RI) and presynaptic inhibition of the SOL alpha motor neuron (D1 inhibition) were assessed by adjusting the unconditioned H-reflex amplitude. Furthermore, during TENS, the time courses of spinal excitability and spinal inhibitory reflexes were assessed via the H-reflex, RI, and D1 inhibition. None of the TENS protocols affected mean RI, whereas D1 inhibition improved significantly following 200-Hz TENS. In a time-series comparison during TENS, repeated stimulation did not produce significant changes in the H-reflex, RI, or D1 inhibition regardless of frequency. These results suggest that the frequency-dependent effect of TENS on spinal reflexes only becomes apparent when RI and D1 inhibition are measured by adjusting the amplitude of the unconditioned H-reflex. However, 200-Hz TENS led to plasticity of synaptic transmission from the antagonist to spastic muscles in stroke survivors.

Impact of an integrated core/SOL description on the R and B T optimization of tokamak fusion reactors

NASA Astrophysics Data System (ADS)

Siccinio, M.; Fable, E.; Angioni, C.; Saarelma, S.; Scarabosio, A.; Zohm, H.

2018-01-01

An updated and improved version of the 0D divertor and scrape-off layer (SOL) model published in Siccinio et al (2016 Plasma Phys. Control. Fusion 58 125011) was coupled with the 1.5D transport code ASTRA (Pereverzev 1991 IPP Report 5/42, Pereverzev and Yushmanov 2002 IPP Report 5/98 and Fable et al 2013 Plasma Phys. Control. Fusion 55 124028). The resulting numerical tool was employed for various scans in the major radius R and in the toroidal magnetic field B T—for different safety factors q, allowable loop voltages V loop and H factors—in order to identify the most convenient choices for an electricity producing tokamak. Such a scenario analysis was carried out evaluating self-consistently, and simultaneously, the core profile and transport effects, which significantly impact on the fusion power outcome, and the divertor heat loads, which represent one of the most critical issues in view of the realization of fusion power plants (Zohm et al 2013 Nucl. Fusion 53 073019 and Wenninger et al 2017 Nucl. Fusion 57 046002). The main result is that, when divertor limits are enforced, the curves at constant electrical power output are closed on themselves in the R-BT plane, and a maximum achievable power exists—i.e. no benefits would be obtained from a further increase in R and B T once the optimum is reached. This result appears as an intrinsic physical limit for all those devices where a radiative SOL is needed to deal with the power exhaust, and where a lower limit on the power crossing the separatrix (e.g. because of the L-H transition) is present.

Fabrication and characterization of novel transparent conducting oxide N-CNT doped ZnO for photovoltaic applications

NASA Astrophysics Data System (ADS)

Benyounes, Anas; Abbas, Naseem; Hammi, Maryama; Ziat, Younes; Slassi, Amine; Zahra, Nida

2018-02-01

The present research reports on the electrical and optical properties of N-CNT doped with ZnO, which is considered as wurtzite transparent and conducting oxide semiconductor structure. The thin films of N-doped carbon nanotubes/ZnO were prepared using sol-gel method, then we carried out investigations in optical and electrical point of view to extract their usefulness in photovoltaic applications. For this purpose, ZnO films were doped by several ratios of carbon nanotubes and N-doped carbon nanotubes. The electrical studies were performed over these two kinds of doped ZnO films, the electrical conductivity has found to be more important for ZnO films filled with N-CNTs. This finding is pretty explained by the electronic conduction hold by nitrogen as charge carriers within carbon nanotubes.

Could titanium oxide coating from a sol-gel process make stone baskets more resistant to laser radiation at 2.1 μm?

PubMed

Cordes, Jens; Nguyen, Felix; Heidenau, Frank; Jocham, Dieter

2012-10-19

Stone baskets could be easily destroyed by Holmium:YAG-laser at an endourologic treatment, with respect to this, we try to improve the resistance by coating them with a titanium oxide layer. The layer was established by a sol-gel-process. Six new baskets (Equadus, Opi Med, Ettlingen, Germany) were used: 1.8 Ch. with 4 wires (diameter 0.127 mm). Three baskets were coated with a layer of titanium oxide established by a sol-gel process at the BioCerEntwicklungs GmbH in Bayreuth (~100 nanometres thickness). The lithotripter was a Holmium:YAG laser (Auriga XL, Starmedtec, Starnberg, Germany). 10 uncoated and 10 coated wires were tested with 610 mJ (the minimal clinical setting) and 2 uncoated and 2 coated wires were tested with 110 mJ. The wires were locked in a special holding instrument under water and the laser incident angle was 90°. The endpoint was gross visible damage to the wire and loss of electric conduction. Only two coated wires resisted two pulses (one in the 610 mJ and one in the 110 mJ setting). All other wires were destroyed after one pulse. This was the first attempt at making stone baskets more resistant to a Holmium:YAG laser beam. Titanium oxide deposited by a sol-gel-process on a titanium-nickel alloy did not result in better resistance to laser injuries.

The Effects of Vanadium Pentoxide to Oxalic Acid Ratio and Different Atmospheres on the Formation of VO2 Nanopowders Synthesized via Sol-Gel Method

NASA Astrophysics Data System (ADS)

Vostakola, Mohsen Fallah; Yekta, Bijan Eftekhari; Mirkazemi, Seyed Mohammad

2017-11-01

Thermochromic VO2 nanopowders were synthesized via the sol-gel method through mixing oxalic acid and vanadium pentoxide in ethanol. We investigated the effect of oxalic acid to vanadium pentoxide ratio on the formation of final product and found that excessive oxalic acid reduced the final product from VO2 to V2O3. Because decreasing the oxalic acid to vanadium pentoxide ratio is a time-consuming process, oxygen was introduced by using a low-porosity alumina tube. The heat treatment was performed inside an electrical tube furnace and in a variety of atmospheres, including pure nitrogen (99.999% purity) and nitrogen containing 5 vol.%, 10 vol.%, and 15 vol.% hydrogen. According to x-ray diffraction (XRD) results, the appropriate atmosphere for synthesizing VO2 nanopowder was the one which contained 10 vol.% hydrogen. In order to decrease the transition temperature in VO2 from 63.5°C to room temperature, W6+ doping was done by adding different amounts of tungstic acid sol to vanadium sol precursor. Differential scanning calorimetry (DSC) results showed that W6+ reduced the transition temperature of VO2 approximately 23°C/wt.%. Lattice straining estimated from XRD results confirmed that VO2 was doped. XRD results at 25°C and 100°C along with DSC results indicated that VO2 was transformed from a low-temperature monoclinic phase to a high-temperature rutile one along this temperature interval.

Brain machine interfaces combining microelectrode arrays with nanostructured optical biochemical sensors

NASA Astrophysics Data System (ADS)

Hajj-Hassan, Mohamad; Gonzalez, Timothy; Ghafer-Zadeh, Ebrahim; Chodavarapu, Vamsy; Musallam, Sam; Andrews, Mark

2009-02-01

Neural microelectrodes are an important component of neural prosthetic systems which assist paralyzed patients by allowing them to operate computers or robots using their neural activity. These microelectrodes are also used in clinical settings to localize the locus of seizure initiation in epilepsy or to stimulate sub-cortical structures in patients with Parkinson's disease. In neural prosthetic systems, implanted microelectrodes record the electrical potential generated by specific thoughts and relay the signals to algorithms trained to interpret these thoughts. In this paper, we describe novel elongated multi-site neural electrodes that can record electrical signals and specific neural biomarkers and that can reach depths greater than 8mm in the sulcus of non-human primates (monkeys). We hypothesize that additional signals recorded by the multimodal probes will increase the information yield when compared to standard probes that record just electropotentials. We describe integration of optical biochemical sensors with neural microelectrodes. The sensors are made using sol-gel derived xerogel thin films that encapsulate specific biomarker responsive luminophores in their nanostructured pores. The desired neural biomarkers are O2, pH, K+, and Na+ ions. As a prototype, we demonstrate direct-write patterning to create oxygen-responsive xerogel waveguide structures on the neural microelectrodes. The recording of neural biomarkers along with electrical activity could help the development of intelligent and more userfriendly neural prosthesis/brain machine interfaces as well as aid in providing answers to complex brain diseases and disorders.

Combining inkjet printing and sol-gel chemistry for making pH-sensitive surfaces.

PubMed

Orsi, Gianni; De Maria, Carmelo; Montemurro, Francesca; Chauhan, Veeren M; Aylott, Jonathan W; Vozzi, Giovanni

2015-01-01

Today biomedical sciences are experiencing the importance of imaging biological parameters with luminescence methods. Studying 2D pH distribution with those methods allows building knowledge about complex cellular processes. Immobilizing pH sensitive nanoparticles inside hydrogel matrixes, in order to guarantee a proper SNR, could easily make stable and biocompatible 2D sensors. Inkjet printing is also well known as tool for printing images onto porous surfaces. Recently it has been used as a free-form fabrication method for building three-dimensional parts, and now is being explored as a way of printing electrical and optical devices. Inkjet printing was used either as a rapid prototyping method for custom biosensors. Sol-gel method is naturally bound with inkjet, because the picoliter-sized ink droplets evaporate quickly, thus allowing quick sol-gel transitions on the printed surface. In this work will be shown how to merge those technologies, in order to make a nanoparticles doped printable hydrogel, which could be used for making 2D/3D smart scaffolds able to monitor cell activities. An automated image analysis system was developed in order to quickly have the pH measurements from pH nanosensors fluorescence images.

Density Limit due to SOL Convection

NASA Astrophysics Data System (ADS)

D'Ippolito, D. A.; Myra, J. R.; Russell, D. A.

2004-11-01

Recent measurements on C-Mod(M. Greenwald, Plasma Phys. Contr. Fusion 44), R27 (2002). suggest there is a density limit due to rapid convection in the SOL: this region starts in the far SOL but expands inward to the separatrix as the density approaches the Greenwald limit. This idea is supported by a recent analysis(D. A. Russell et al., Lodestar Report LRC-04-99 (2004).) of a 3D BOUT code turbulence simulation(X. Q. Xu et al., Bull. APS 48), 184 (2003), paper KP1-20. with neutral fueling of the X-point region. Our work suggests that rapid outwards convection of plasma by turbulent coherent structures (``blobs'') occurs when the X-point collisionality is sufficiently large. Here, we calculate a density limit due to loss of thermal equilibrium in the edge plasma due to rapid radial convective heat transport. We expect a synergistic effect between blob convection and X-point cooling. The cooling increases the parallel resistivity at the X-point, ``disconnects'' the blobs electrically from the sheaths, and increases their radial velocity,(D.A. D'Ippolito et al., 2004 Sherwood Meeting, paper 1C 43.) which in turn further cools the X-points. Progress on a theoretical model will be reported.

Effects of Muscle Atrophy on Motor Control: Cage-size Effects

NASA Technical Reports Server (NTRS)

Stuart, D. G.

1985-01-01

Two populations of male Sprague-Dawley rats were raised either in conventional minimum-specification cages or in a larger cage. When the animals were mature (125 to 150 d), the physiological status of the soleus (SOL) and extensor digitorum longus (EDL) muscles of the small- and large-cage animals were compared. Analysis of whole-muscle properties including the performance of the test muscle during a standardized fatigue test in which the nerve to the test muscle was subjected to supramaximal intermittent stimulation shows: (1) the amplitude, area, mean amplitude, and peak-to-peak rate of the compound muscle action potential decreased per the course of the fatigue test; (2) cage size did not affect the profile of changes for any of the action-potential measurements; (3) changes exhibited in the compound muscle action potential by SOL and EDL were substantially different; and (4) except for SOL of the large-cage rats, there was a high correlation between all four measures of the compound muscle action potential and the peak tetanic force during the fatigue test; i.e., either the electrical activity largely etermines the force profile during the fatigue test or else contractile-related activity substantially affects the compound muscle action potential.

A micro oxygen sensor based on a nano sol-gel TiO2 thin film.

PubMed

Wang, Hairong; Chen, Lei; Wang, Jiaxin; Sun, Quantao; Zhao, Yulong

2014-09-03

An oxygen gas microsensor based on nanostructured sol-gel TiO2 thin films with a buried Pd layer was developed on a silicon substrate. The nanostructured titania thin films for O2 sensors were prepared by the sol-gel process and became anatase after heat treatment. A sandwich TiO2 square board with an area of 350 μm × 350 μm was defined by both wet etching and dry etching processes and the wet one was applied in the final process due to its advantages of easy control for the final structure. A pair of 150 nm Pt micro interdigitated electrodes with 50 nm Ti buffer layer was fabricated on the board by a lift-off process. The sensor chip was tested in a furnace with changing the O2 concentration from 1.0% to 20% by monitoring its electrical resistance. Results showed that after several testing cycles the sensor's output becomes stable, and its sensitivity is 0.054 with deviation 2.65 × 10(-4) and hysteresis is 8.5%. Due to its simple fabrication process, the sensor has potential for application in environmental monitoring, where lower power consumption and small size are required.

Synthesis of zinc oxide thin films prepared by sol-gel for specific bioactivity

NASA Astrophysics Data System (ADS)

Adam, Tijjani; Basri, B.; Dhahi, Th. S.; Mohammed, Mohammed; Hashim, U.; Noriman, N. Z.; Dahham, Omar S.

2017-09-01

Zinc oxide (ZnO) thin films this device to used for many application like chemical sensor, biosensor, solar energy, etc but my project to use for bioactivity(biosensor). Zinc oxide (ZnO) thin films have been grown using sol-gel technique. Characterization was done using Scanning Electron Microscope (SEM), Energy Dispersive X-ray(EDX) and Electrical Measurement(I-V). ZnO thin film was successfully synthesized using low cost sol-gel spin coating method. The coupling of DNA probe to ZnO thin film supports modified with carboxylic acid (COOH) is certainly the best practical method to make DNA immobilization and it does not require any coupling agent which could be a source of variability during the spotting with an automatic device. So, selected this coupling procedure for further experiments. The sensor was tested with initial trial with low concentrated DNA and able to detect detection of the disease effectively. Silicon-on-insulator (SOI) wafer device with ZnO can detect at different concentration in order to valid the device capabilities for detecting development. The lowest concentration 1 µM HPV DNA probe can detect is 0.1 nM HPV target DNA.

Characterization and Mitigation of ICRF Antenna - Plasma Edge Interaction

NASA Astrophysics Data System (ADS)

Hong, Rongjie; Tynan, George; Wukitch, Steve; Lin, Yijun; Terry, Jim; Chilenski, M.; Golfinopoulos, T.; Hubbard, A.; Mumgaard, R. T.; Perkins, R.; Reinke, M. L.; Alcator C-Mod Team

2017-10-01

Recent experiments reveal that RF-induced potentials (VRF) in the SOL and impurity source at the antenna can be reduced to background levels via optimizing the power ratio between the inner and outer current straps, Pcent /Pout . Experiments indicate the antenna impurity source reduction for the field aligned antenna is due to geometrical alignment rather than electrical symmetry. Additional experiments performed without an optimized Pcent /Pout showed that VRF and the associated convection cells do not influence the impurity penetration or core impurity confinement. These results suggest the core impurity contamination associated with ICRF heating is dominated by an increased impurity source rather than a change in impurity transport. Further, the convective cell strength was expected to scale inversely with B-field. The observed poloidal velocity (measure of convective cell strength), however, decreased less than expected. In addition, the measured maximum VRF increased and penetrated farther into the SOL at higher B-field and plasma current. Results also suggest VRF is strongly influenced by the SOL plasma parameters rather than by RF parameters. Work supported by the U.S. DoE, Office of Science, Office of Fusion Energy Sciences, User Facility Alcator C-Mod under DE-FC02-99ER54512 and DE-SC 0010720.

Adjustable rheology of fumed silica dispersion in urethane prepolymers: Composition-dependent sol and gel behaviors and energy-mediated shear responses

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

Zheng, Zhong, E-mail: 11329038@zju.edu.cn; Song, Yihu, E-mail: s-yh0411@zju.edu.cn; Wang, Xiang, E-mail: 11229036@zju.edu.cn

2015-07-15

Variation of colloidal and interfacial interactions leads to a microstructural diversity in fumed silica dispersions exhibiting absolutely different sol- or gel-like rheological responses. In this study, fumed silicas with different surface areas (200–400 m{sup 2}/g) and surface characteristics (hydrophilic or hydrophobic) are dispersed into moisture-cured polyurethane. The microstructures investigated using transmission electron microscope are associated perfectly with three different rheological behaviors: (i) Sols with well-dispersed silica aggregates, (ii) weak gels with agglomerate-linked networks, and (iii) strong gels with concentrated networks of large agglomerates. Though sols and gels are well distinguished by shear thickening or sustained thinning response through steady shearmore » flow test, it is interesting that the sols and weak gels exhibit a uniform modulus plateau-softening-hardening-softening response with increasing dynamic strain at frequency 10 rad s{sup −1} while the strong gels show a sustained softening beyond the linear regime. Furthermore, the onset of softening and hardening can be normalized: The two softening are isoenergetic at mechanical energies of 0.3 J m{sup −3} and 10 kJ m{sup −3}. On the other hand, the hardening is initiated by a critical strain of 60%. The mechanisms involved in the generation of the sol- and the gel-like dispersions and their structural evolutions during shear are thoroughly clarified in relation to the polyols, the characteristic and content of silica and the curing catalysts.« less

Electrical characteristics and density of states of thin-film transistors based on sol-gel derived ZnO channel layers with different annealing temperatures

NASA Astrophysics Data System (ADS)

Wang, S.; Mirkhani, V.; Yapabandara, K.; Cheng, R.; Hernandez, G.; Khanal, M. P.; Sultan, M. S.; Uprety, S.; Shen, L.; Zou, S.; Xu, P.; Ellis, C. D.; Sellers, J. A.; Hamilton, M. C.; Niu, G.; Sk, M. H.; Park, M.

2018-04-01

We report on the fabrication and electrical characterization of bottom gate thin-film transistors (TFTs) based on a sol-gel derived ZnO channel layer. The effect of annealing of ZnO active channel layers on the electrical characteristics of the ZnO TFTs was systematically investigated. Photoluminescence (PL) spectra indicate that the crystal quality of the ZnO improves with increasing annealing temperature. Both the device turn-on voltage (Von) and threshold voltage (VT) shift to a positive voltage with increasing annealing temperature. As the annealing temperature is increased, both the subthreshold slope and the interfacial defect density (Dit) decrease. The field effect mobility (μFET) increases with annealing temperature, peaking at 800 °C and decreases upon further temperature increase. An improvement in transfer and output characteristics was observed with increasing annealing temperature. However, when the annealing temperature reaches 900 °C, the TFTs demonstrate a large degradation in both transfer and output characteristics, which is possibly produced by non-continuous coverage of the film. By using the temperature-dependent field effect measurements, the localized sub-gap density of states (DOSs) for ZnO TFTs with different annealing temperatures were determined. The DOSs for the subthreshold regime decrease with increasing annealing temperature from 600 °C to 800 °C and no substantial change was observed with further temperature increase to 900 °C.

Semiconducting and quartz microbalance (QCM) humidity sensor properties of TiO2 by sol gel calcination method

NASA Astrophysics Data System (ADS)

Yakuphanoglu, Fahrettin

2012-06-01

Titanium dioxide (TiO2) material was synthesized using the sol gel calcination method. The structural properties of the TiO2 semiconductor were investigated by atomic force microscopy. The electrical conductivity of the TiO2 was measured as a function of temperature and TiO2 exhibits a conductivity of 2.55 × 10-6 S/m at room temperature with activation energy of 104 meV. The electrical conductivity of the TiO2 at room temperature is higher than that of nanocrystalline TiO2 (3 × 10-7 S/m) and TiO2 thin film in air (5 × 10-9 S/m) and in vacuum (8.8 × 10-10 S/m). It was found that the electrical transport mechanism of the TiO2 is controlled by thermally activated mechanism. The optical band gap of the TiO2 powder sample was determined to be 3.17 eV, which is good in agreement with the bulk TiO2 (Eg = 3.2 eV). Up to our knowledge, there is no any reported data about the band gap of TiO2 nanopowder based on the diffused reflectance calculation. Quartz crystal microbalance (QCM) TiO2 humidity sensor was prepared. The sensor indicates a large frequency change with an interaction occurred between TiO2 and humidity molecules. The sensor exhibits a good repeatability when it was exposed to the moist air of 65% RH.

Studies of ferroelectric and dielectric properties of pure and doped barium titanate prepared by sol-gel method

NASA Astrophysics Data System (ADS)

Bisen, Supriya; Mishra, Ashutosh; Jarabana, Kanaka M.

2016-05-01

In this work, Barium Titanate (BaTiO3) powders were synthesized via Sol-Gel auto combustion method using citric acid as a chelating agent. We study the behavior of ferroelectric and dielectric properties of pure and doped BaTiO3 on different concentration. To understand the phase and structure of the powder calcined at 900°C were characterized by X-ray Diffraction shows that tetragonal phase is dominant for pure and doped BTO and data fitted by Rietveld Refinement. Electric and Dielectric properties were characterized by P-E Hysteresis and Dielectric measurement. In P-E measurement ferroelectric loop tracer applied for different voltage. The temperature dependant dielectric constant behavior was observed as a function of frequency recorded on hp-Hewlett Packard 4192A, LF impedance, 5Hz-13Hz analyzer.

Low Concentration Fe-Doped Alumina Catalysts Using Sol-Gel and Impregnation Methods: The Synthesis, Characterization and Catalytic Performance during the Combustion of Trichloroethylene.

PubMed

Maldonado, Carolina Solis; De la Rosa, Javier Rivera; Lucio-Ortiz, Carlos J; Hernández-Ramírez, Aracely; Barraza, Felipe F Castillón; Valente, Jaime S

2014-03-12

The role of iron in two modes of integration into alumina catalysts was studied at 0.39 wt% Fe and tested in trichloroethylene combustion. One modified alumina was synthesized using the sol-gel method with Fe added in situ during hydrolysis; another modification was performed using calcined alumina, prepared using the sol-gel method and impregnated with Fe. Several characterization techniques were used to study the level of Fe modification in the γ-Al₂O₃ phase formed and to correlate the catalytic properties during trichloroethylene (TCE) combustion. The introduction of Fe in situ during the sol-gel process influenced the crystallite size, and three iron species were generated, namely, magnetite, maghemite and hematite. The impregnated Fe-alumina formed hematite and maghemite, which were highly dispersed on the γ-Al₂O 3 surface. The X-ray photoelectron spectra (XPS), FT-IR and Mössbauer spectroscopy analyses revealed how Fe interacted with the γ-Al₂O₃ lattice in both catalysts. The impregnated Fe-catalyst showed the best catalytic performance compared to the catalyst that was Fe-doped in situ by the sol-gel method; both had better catalytic activity than pure alumina. This difference in activity was correlated with the accessibility of the reactants to the hematite iron species on the surface. The chlorine poisoning for all three catalysts was less than 1.8%.

Experimental evidence of edge intrinsic momentum source driven by kinetic ion loss and edge radial electric fields in tokamaks

DOE PAGES

Boedo, J. A.; deGrassie, J. S.; Grierson, B.; ...

2016-09-21

Here, bulk ion toroidal velocity profiles, V D+ ||, peaking at 40–60 km/s are observed with Mach probes in a narrow edge region of DIII-D discharges without external momentum input. This intrinsic rotation can be well reproduced by a first principle, collisionless kinetic loss model of thermal ion loss that predicts the existence of a loss-cone distribution in velocity space resulting in a co-Ip directed velocity. We consider two kinetic models, one of which includes turbulence-enhanced momentum transport, as well as the Pfirsch-Schluter (P-S) fluid mechanism. We measure a fine structure of the boundary radial electric field, Er, insofar ignored,more » featuring large (10–20 kV/m) positive peaks in the scrape off layer (SOL) at, or slightly inside, the last closed flux surface of these low power L- and H-mode discharges in DIII-D. The Er structure significantly affects the ion-loss model, extended to account for a non-uniform electric field. We also find that V D+ || is reduced when the magnetic topology is changed from lower single null to upper single null. The kinetic ion loss model containing turbulence-enhanced momentum transport can explain the reduction, as we find that the potential fluctuations decay with radius, while we need to invoke a topology-enhanced collisionality on the simpler kinetic model. The P-S mechanism fails to reproduce the damping. We show a clear correlation between the near core V C6+ || velocity and the peak edge V D+ || in discharges with no external torque, further supporting the hypothesis that ion loss is the source for intrinsic torque in the present tokamaks. However, we also show that when external torque is injected in the core, it can complete with, and eventually overwhelm, the edge source, thus determining the near SOL flows. Finally, we show some additional evidence that the ion/electron distribution in the SOL is non-Maxwellian.« less

Still Giving Thanks for Good Health

NASA Technical Reports Server (NTRS)

2005-01-01

[figure removed for brevity, see original site] Click on the image for Still Giving Thanks for Good Health (QTVR)

NASA's Mars Exploration Rover Spirit took this full-circle panorama of the region near 'Husband Hill' (the peak just to the left of center) over the Thanksgiving holiday, before ascending farther. Both the Spirit and Opportunity rovers are still going strong, more than a year after landing on Mars.

This 360-degree view combines 243 images taken by Spirit's panoramic camera over several martian days, or sols, from sol 318 (Nov. 24, 2004) to sol 325 (Dec. 2, 2004). It is an approximately true-color rendering generated from images taken through the camera's 750-, 530-, and 480-nanometer filters. The view is presented here in a cylindrical projection with geometric seam correction.

Spirit is now driving up the slope of Husband Hill along a path about one-quarter of the way from the left side of this mosaic.

Dielectric Properties of Sol-Gel Derived Barium Strontium Titanate and Microwave Sintering of Ceramics

NASA Astrophysics Data System (ADS)

Selmi, Fathi A.

This thesis consists of two areas of research: (1) sol-gel processing of Ba_{rm 1-x}Sr_{rm x} TiO_3 ceramics and their dielectric properties measurement; and (2) microwave versus conventional sintering of ceramics such as Al_2 O_3, Ba_{ rm 1-x}Sr_{rm x}TiO_3, Sb-doped SnO _2 and YBa_2Cu _3O_7. Sol-gel powders of BaTiO_3, SrTiO_3, and their solid solutions were synthesized by the hydrolysis of titanium isopropoxide and Ba and Sr methoxyethoxides. The loss tangent and dielectric constant of both sol-gel and conventionally prepared and sintered Ba_{rm 1-x}Sr _{rm x}TiO _3 ceramics were investigated at high frequencies. The sol-gel prepared ceramics showed higher dielectric constant and lower loss compared to those prepared conventionally. Ba _{rm 1-x}Sr _{rm x}TiO_3 ceramics were tunable with applied bias, indicating the potential use of this material for phase shifter applications. Porous Ba_{0.65}Sr _{0.35}TiO_3 was also investigated to lower the dielectric constant. Microwave sintering of alpha -Al_2O_3 and SrTiO_3 was investigated using an ordinary kitchen microwave oven (2.45 GHz; 600 Watts). The use of microwaves with good insulation of alpha -Al_2O_3 and SrTiO_3 samples resulted in their rapid sintering with good final densities of 96 and 98% of the theoretical density, respectively. A comparison of grain size for conventionally and microwave sintered SrTiO_3 samples did not show a noticeable difference. However, the grain size of microwave sintered alpha-Al_2O _3 was found to be larger than that of conventionally sintered sample. These results show that rapid sintering of ceramics can be achieved by using microwave radiation. The sintering behavior of coprecipitated Sb-doped SnO_2 was investigated using microwave power absorption. With microwave power, samples were sintered at 1450^circC for 20 minutes and showed a density as high as 99.9% of theoretical. However, samples fired in a conventional electric furnace at the same temperature for 4 hours showed only 60% of theoretical density. Microwave sintering also led to improvement in terms of uniform structure and electrical properties. Ba_{0.65}Sr _{0.35}TiO_3 was sintered using the microwave power at 1300 ^circC for 10 minutes. A density of 99% was achieved with small and uniform grain size. Superconducting powders have been successfully prepared by the sol-gel process and sintered and annealed using microwave power. Sintering and densification was achieved in a shorter time with microwave heating than with conventional heating and microwave heating appears to result in refined microstructure.

Self-organized micro-holes on titania based sol-gel films under continuous direct writing with a continuous wave ultraviolet laser

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

Bakhti, S.; Destouches, N.; Gamet, E.

The microstructuring of titania based sol-gel films is investigated by direct writing with a continuous wave ultraviolet laser beam emitting at 244 nm. Depending on the exposure conditions, the films exhibit a volume expansion, a volume shrinkage, a self-shaped delamination, or are damaged. This paper is mainly focused on the regime where spontaneous local delamination occurs, which corresponds to a narrow range of laser irradiances and writing speeds. In this regime, self-organized round-shape micro-holes opened on the substrate are generated.

Luminescent and scintillation properties of composites based on sol-gel SiO2 matrices and organic scintillators

NASA Astrophysics Data System (ADS)

Vyagin, O. G.; Bespalova, I. I.; Masalov, A. A.; Zelenskaya, O. V.; Tarasov, V. A.; Malyukin, Yu. V.

2014-11-01

Luminescent composites based on SiO2 matrices synthesized using the sol-gel method and organic scintillators PPO and o-POPOP are produced, and their optical, luminescent, and scintillation characteristics are studied. It is shown that these composites generate an intense photoluminescence signal, possess a nanosecond decay time, and have a transparency in the range of 400-700 nm of no less than 70%. The absolute light output during excitation by α radiation with an energy of 5.46 MeV is 4400-5100 photon/MeV, and the amplitude resolution is 27-32%.

Role of grain and grain boundary on the electrical and thermal conductivity of Bi0.9Y0.1Fe0.9Mn0.1O3 ceramics

NASA Astrophysics Data System (ADS)

Pandey, Rabichandra; Panda, Chandrakanta; Kumar, Pawan; Pradhan, Lagen Kumar; Kar, Manoranjan

2017-05-01

Role of grain and grain boundary on electrical and thermal conductivity of Bi0.9Y0.1Fe0.9Mn0.1O3 ceramic was investigated systematically. Tartaric acid modified sol gel method was used to synthesize the compound. X-ray diffraction technique was used to confirm the formation of single phase orthorhombic (Pbnm) structure. Electrical properties of the sample were measured with a wide frequency range from 100Hz to 10MHz at different temperature from 40°C to 250°C. AC impedance studies indicate the presence of grain and grain boundary effect. The negative temperature coefficient of resistance (NTCR) behaviour of the compound has been confirmed by the cole-cole plot. DC electrical and thermal conductivities of the compound were explained on the basis of grain and grain boundaries.

Electrical properties of palladium-doped CaCu3Ti4O12 ceramics

NASA Astrophysics Data System (ADS)

Singh, Arashdeep; Md Mursalin, Sk.; Rana, P.; Sen, Shrabanee

2015-09-01

The effect of doping palladium (Pd) at the Cu site of CaCu3Ti4O12 powders (CCPTO) synthesized by sol-gel technique on electrical properties was studied. XRD analysis revealed the formation of CCTO and CCPTO ceramics with some minor quantities of impurities. SEM micrographs revealed that the grain size decreased with Pd doping. TEM micrographs of CCPTO powder showed the formation of irregular-shaped particles of ~40 nm. The dielectric constant and dielectric loss showed a significant enhancement with Pd doping. A significant decrease in grain-boundary resistance with Pd doping was ascertained by impedance spectroscopy study.

Electrical and magnetic properties of nano-sized magnesium ferrite

NASA Astrophysics Data System (ADS)

T, Smitha; X, Sheena; J, Binu P.; Mohammed, E. M.

2015-02-01

Nano-sized magnesium ferrite was synthesized using sol-gel techniques. Structural characterization was done using X-ray diffractometer and Fourier Transform Infrared Spectrometer. Vibration Sample Magnetometer was used to record the magnetic measurements. XRD analysis reveals the prepared sample is single phasic without any impurity. Particle size calculation shows the average crystallite size of the sample is 19nm. FTIR analysis confirmed spinel structure of the prepared samples. Magnetic measurement study shows that the sample is ferromagnetic with high degree of isotropy. Hysterisis loop was traced at temperatures 100K and 300K. DC electrical resistivity measurements show semiconducting nature of the sample.

The structural and electrical properties of polycrystalline La0.8Ca0.17Ag0.03MnO3 manganites

NASA Astrophysics Data System (ADS)

Ruli, F.; Kurniawan, B.; Imaduddin, A.

2018-04-01

In this paper, the authors report the electrical properties of polycrystalline La0.8Ca0.17Ag0.03MnO3 manganites synthesized using sol-gel method. The X-ray diffraction (XRD) patterns of polycrystalline La0.8Ca0.17Ag0.03MnO3 samples reveal an orthorhombic perovskite structure with Pnma space group. Analysis using energy dispersive X-ray (EDX) confirms that the sample contains all expected chemical elements without any additional impurity. The measurement of resistivity versus temperature using cryogenic magnetometer was performed to investigate the electrical properties. The results show that the electrical resistivity of polycrystalline La0.8Ca0.17Ag0.03MnO3 exhibits metalic behavior below 244 K. The temperature dependence of electrical resistivity dominantly emanates from electron-electron scattering and the grain/domain boundary play a important role in conduction mechanism in polycrystalline La0.8Ca0.17Ag0.03MnO3.

Effect of molarity on sol-gel routed nano TiO2 thin films

NASA Astrophysics Data System (ADS)

Lourduraj, Stephen; Williams, Rayar Victor

The nanostructured titanium dioxide (TiO2) thin films have been prepared for the molar concentrations of titanium tetra isopropoxide (TTIP) 0.05M, 0.1M, 0.15M and 0.2M by sol-gel routed spin coating technique with calcination at 450∘C. The processing parameters such as, pH value (8), catalyst HCl (0.1ml), spin speed (3000rpm) and calcination temperature (450∘C) are optimized. The crystalline nature and surface morphology were analyzed by XRD, SEM and AFM analysis. The XRD results confirm that the films are crystalline with anatase phase, and are nanostructured. The SEM micrographs of the TiO2 film reveal the spherical nature of the particle. AFM analysis establishes that the uniformity of the TiO2 thin film was optimized at 0.2M. The optical measurements show that the transmittance depends on the molarity, and the optical band gap energy of TiO2 films is found to be inversely proportional to molarity. The I-V characteristics exhibit that the molarity strongly influences the electrical conductivity of the film. The results indicate that the significant effect of molarity on structural, optical and electrical properties of the nanostructured TiO2 thin films will be useful to photovoltaic application.

Study of nanoparticles TiO{sub 2} thin films on p-type silicon substrate using different alcoholic solvents

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

Muaz, A. K. M.; Ruslinda, A. R.; Ayub, R. M.

2016-07-06

In this paper, sol-gel method spin coating technique is adopted to prepare nanoparticles titanium dioxide (TiO{sub 2}) thin films. The prepared TiO{sub 2} sol was synthesized using titanium butoxide act as a precursor and subjected to deposited on the p-type silicon oxide (p-SiO{sub 2}) and glass slide substrates under room temperature. The effect of different alcoholic solvents of methanol and ethanol on the structural, morphological, optical and electrical properties were systematically investigated. The coated TiO{sub 2} thin films were annealed in furnace at 773 K for 1 h. The structural properties of the TiO{sub 2} films were examined with X-raymore » Diffraction (XRD). From the XRD analysis, both solvents showing good crystallinity with anatase phase were the predominant structure. Atomic Force Microscopy (AFM) was employed to study the morphological of the thin films. The optical properties were investigated by Ultraviolet-visible (UV-Vis) spectroscopy were found that ethanol as a solvent give a higher optical transmittance if compare to the methanol solvent. The electrical properties of the nanoparticles TiO{sub 2} thin films were measured using two-point-probe technique.« less

Studies of ferroelectric and dielectric properties of pure and doped barium titanate prepared by sol-gel method

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

Bisen, Supriya; Mishra, Ashutosh; Jarabana, Kanaka M.

2016-05-23

In this work, Barium Titanate (BaTiO{sub 3}) powders were synthesized via Sol-Gel auto combustion method using citric acid as a chelating agent. We study the behavior of ferroelectric and dielectric properties of pure and doped BaTiO{sub 3} on different concentration. To understand the phase and structure of the powder calcined at 900°C were characterized by X-ray Diffraction shows that tetragonal phase is dominant for pure and doped BTO and data fitted by Rietveld Refinement. Electric and Dielectric properties were characterized by P-E Hysteresis and Dielectric measurement. In P-E measurement ferroelectric loop tracer applied for different voltage. The temperature dependant dielectricmore » constant behavior was observed as a function of frequency recorded on hp-Hewlett Packard 4192A, LF impedance, 5Hz-13Hz analyzer.« less

Photoluminescence and photoconductivity studies on amorphous and crystalline ZnO thin films obtained by sol-gel method

NASA Astrophysics Data System (ADS)

Valverde-Aguilar, G.; Manríquez Zepeda, J. L.

2015-03-01

Amorphous and crystalline ZnO thin films were obtained by the sol-gel process. A precursor solution of ZnO was synthesized by using zinc acetate dehydrate as inorganic precursor at room temperature. The films were spin-coated on silicon and glass wafers and gelled in humid air. The films were calcined at 450 °C for 15 min to produce ZnO nanocrystals with a wurtzite structure. Crystalline ZnO film exhibits an absorption band located at 359 nm (3.4 eV). Photoconductivity technique was used to determine the charge transport mechanism on both kinds of films. Experimental data were fitted with straight lines at darkness and under illumination at 355 and 633 nm wavelengths. This indicates an ohmic behavior. The photovoltaic and photoconductivity parameters were determined from the current density versus the applied electrical field results.

Sol-gel synthesis of Cu-doped p-CdS nanoparticles and their analysis as p-CdS/n-ZnO thin film photodiode

NASA Astrophysics Data System (ADS)

Arya, Sandeep; Sharma, Asha; Singh, Bikram; Riyas, Mohammad; Bandhoria, Pankaj; Aatif, Mohammad; Gupta, Vinay

2018-05-01

Copper (Cu) doped p-CdS nanoparticles have been synthesized via sol-gel method. The as-synthesized nanoparticles were successfully characterized and implemented for fabrication of Glass/ITO/n-ZnO/p-CdS/Al thin film photodiode. The fabricated device is tested for small (-1 V to +1 V) bias voltage. Results verified that the junction leakage current within the dark is very small. During reverse bias condition, the maximum amount of photocurrent is obtained under illumination of 100 μW/cm2. Electrical characterizations confirmed that the external quantum efficiency (EQE), gain and responsivity of n-ZnO/p-CdS photodiode show improved photo response than conventional p-type materials for such a small bias voltage. It is therefore revealed that the Cu-doped CdS nanoparticles is an efficient p-type material for fabrication of thin film photo-devices.

High Mobility Flexible Amorphous IGZO Thin-Film Transistors with a Low Thermal Budget Ultra-Violet Pulsed Light Process.

PubMed

Benwadih, M; Coppard, R; Bonrad, K; Klyszcz, A; Vuillaume, D

2016-12-21

Amorphous, sol-gel processed, indium gallium zinc oxide (IGZO) transistors on plastic substrate with a printable gate dielectric and an electron mobility of 4.5 cm 2 /(V s), as well as a mobility of 7 cm 2 /(V s) on solid substrate (Si/SiO 2 ) are reported. These performances are obtained using a low temperature pulsed light annealing technique. Ultraviolet (UV) pulsed light system is an innovative technique compared to conventional (furnace or hot-plate) annealing process that we successfully implemented on sol-gel IGZO thin film transistors (TFTs) made on plastic substrate. The photonic annealing treatment has been optimized to obtain IGZO TFTs with significant electrical properties. Organic gate dielectric layers deposited on this pulsed UV light annealed films have also been optimized. This technique is very promising for the development of amorphous IGZO TFTs on plastic substrates.

Polymer-Templated LiFePO4/C Nanonetworks as High-Performance Cathode Materials for Lithium-Ion Batteries.

PubMed

Fischer, Michael G; Hua, Xiao; Wilts, Bodo D; Castillo-Martínez, Elizabeth; Steiner, Ullrich

2018-01-17

Lithium iron phosphate (LFP) is currently one of the main cathode materials used in lithium-ion batteries due to its safety, relatively low cost, and exceptional cycle life. To overcome its poor ionic and electrical conductivities, LFP is often nanostructured, and its surface is coated with conductive carbon (LFP/C). Here, we demonstrate a sol-gel based synthesis procedure that utilizes a block copolymer (BCP) as a templating agent and a homopolymer as an additional carbon source. The high-molecular-weight BCP produces self-assembled aggregates with the precursor-sol on the 10 nm scale, stabilizing the LFP structure during crystallization at high temperatures. This results in a LFP nanonetwork consisting of interconnected ∼10 nm-sized particles covered by a uniform carbon coating that displays a high rate performance and an excellent cycle life. Our "one-pot" method is facile and scalable for use in established battery production methodologies.

Memristive behavior of the SnO2/TiO2 interface deposited by sol-gel

NASA Astrophysics Data System (ADS)

Boratto, Miguel H.; Ramos, Roberto A.; Congiu, Mirko; Graeff, Carlos F. O.; Scalvi, Luis V. A.

2017-07-01

A novel and cheap Resistive Random Access Memory (RRAM) device is proposed within this work, based on the interface between antimony doped Tin Oxide (4%at Sb:SnO2) and Titanium Oxide (TiO2) thin films, entirely prepared through a low-temperature sol-gel process. The device was fabricated on glass slides using evaporated aluminum electrodes. Typical bipolar memristive behavior under cyclic voltage sweeping and square wave voltages, with well-defined high and low resistance states (HRS and LRS), and set and reset voltages are shown in our samples. The switching mechanism, explained by charges trapping/de-trapping by defects in the SnO2/TiO2 interface, is mainly driven by the external electric field. The calculated on/off ratio was about 8 × 102 in best conditions with good reproducibility over repeated measurement cycles under cyclic voltammetry and about 102 under applied square wave voltage.

Synthesis of ZnO thin film by sol-gel spin coating technique for H2S gas sensing application

NASA Astrophysics Data System (ADS)

Nimbalkar, Amol R.; Patil, Maruti G.

2017-12-01

In this present work, zinc oxide (ZnO) thin film synthesized by a simple sol-gel spin coating technique. The structural, morphology, compositional, microstructural, optical, electrical and gas sensing properties of the film were studied by using XRD, FESEM, EDS, XPS, HRTEM, Raman, FTIR and UV-vis techniques. The ZnO thin film shows hexagonal wurtzite structure with a porous structured morphology. Gas sensing performance of synthesized ZnO thin film was tested initially for H2S gas at different operating temperatures as well as concentrations. The maximum gas response is achieved towards H2S gas at 300 °C operating temperature, at 100 ppm gas concentration as compared to other gases like CH3OH, Cl2, NH3, LPG, CH3COCH3, and C2H5OH with a good stability.

77 FR 37779 - Airworthiness Directives; Agusta S.p.A. Helicopters

Federal Register 2010, 2011, 2012, 2013, 2014

2012-06-25

... numbers (S[sol]Ns) except S[sol]Ns 31002, 31003, 31004, and 31007. EASA advises that laboratory tests... helicopters, S[sol]Ns 31005 up to S[sol]N 31143, except for S[sol]Ns 31007, 31037, 31038, 31094; S[sol]N 31112; S[sol]Ns 31146 up to S[sol]N 31148; S[sol]N 31155; S[sol]Ns 31201 up to S[sol]N 31218; and S[sol]Ns...

Low Concentration Fe-Doped Alumina Catalysts Using Sol-Gel and Impregnation Methods: The Synthesis, Characterization and Catalytic Performance during the Combustion of Trichloroethylene

PubMed Central

Maldonado, Carolina Solis; De la Rosa, Javier Rivera; Lucio-Ortiz, Carlos J.; Hernández-Ramírez, Aracely; Castillón Barraza, Felipe F.; Valente, Jaime S.

2014-01-01

The role of iron in two modes of integration into alumina catalysts was studied at 0.39 wt% Fe and tested in trichloroethylene combustion. One modified alumina was synthesized using the sol-gel method with Fe added in situ during hydrolysis; another modification was performed using calcined alumina, prepared using the sol-gel method and impregnated with Fe. Several characterization techniques were used to study the level of Fe modification in the γ-Al2O3 phase formed and to correlate the catalytic properties during trichloroethylene (TCE) combustion. The introduction of Fe in situ during the sol-gel process influenced the crystallite size, and three iron species were generated, namely, magnetite, maghemite and hematite. The impregnated Fe-alumina formed hematite and maghemite, which were highly dispersed on the γ-Al2O3 surface. The X-ray photoelectron spectra (XPS), FT-IR and Mössbauer spectroscopy analyses revealed how Fe interacted with the γ-Al2O3 lattice in both catalysts. The impregnated Fe-catalyst showed the best catalytic performance compared to the catalyst that was Fe-doped in situ by the sol-gel method; both had better catalytic activity than pure alumina. This difference in activity was correlated with the accessibility of the reactants to the hematite iron species on the surface. The chlorine poisoning for all three catalysts was less than 1.8%. PMID:28788556

Low temperature synthesis and enhanced electrical properties by substitution of Al3+ and Cr3+ in Co-Ni nanoferrites

NASA Astrophysics Data System (ADS)

Pervaiz, Erum; Gul, I. H.

2013-10-01

Aluminum and chromium substituted Co-Ni spinel nanoferrites were prepared by sol-gel auto combustion method. Structural parameters along with electrical and magnetic properties have been investigated in the present work. Crystallite sizes of nano ferrite estimated from the peak (311) lies in the range of 13-21 nm ±2 nm and compared with crystallite sizes calculated from Williamsons-Hall plots. DC electrical resistivity variations due to the concentration of aluminum and chromium in the host ferrite have been measured from 368 K to 573 K. Increase in the room temperature DC electrical resistivity was observed up to a concentration x=0.2 and then decreases for x >0.2. Dielectric parameters (real and imaginary part of complex permittivity, dielectric loss tangent) were studied as a function of frequency (20 Hz-5 MHz) and a decrease in the dielectric parameters was observed due to substitution of nickel, aluminum and chromium ions in cobalt nanoferrites. AC conductivity, complex impedance and complex electrical modulus were studied as a function of frequency for the conduction and relaxation mechanisms in the present ferrite system. Saturation magnetization, coercivity, canting angles and magneto crystalline anisotropy variations with composition were observed and presented for the present ferrites under an applied magnetic field of 10 kOe at room temperature. It was found that both magnetization and coercivity decreases with increase in the concentration of aluminum and chromium along with a decrease in the anisotropy parameters. High DC resistivity with low dielectric parameters of the present nanoferrites make them suitable for high frequency and electromagnetic wave absorbing devices. High purity mixed Co-Ni-Al-Cr nanoferrites have been prepared by sol-gel auto combustion method. DC electrical resistivity increases due to substitution of Al3+ and Cr3+. Complex permittivity decrease for Co-Ni-Al-Cr nanoferrites. Detailed AC response analysis has been presented for mixed Co-Ni-Al-Cr nanoferrites. Magnetization and coercively reduces for Al3+ and Cr3+ doped Co-Ni ferrite nanoparticles showing that material is becoming soft magnetic.

75 FR 70936 - Accreditation and Approval of Inspectorate America Corporation, as a Commercial Gauger and...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-11-19

... laboratories. http:[sol][sol]cbp.gov[sol]xp[sol]cgov[sol]import[sol]operations-- support[sol]labs--scientific--svcs[sol]commercial--gaugers[sol]. DATES: The accreditation and approval of Inspectorate America...

75 FR 70935 - Accreditation and Approval of Inspectorate America Corporation, as a Commercial Gauger and...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-11-19

... laboratories. http:[sol][sol]cbp.gov[sol]xp[sol]cgov[sol]import[sol]operations-- support[sol]labs--scientific--svcs[sol]commercial--gaugers[sol]. DATES: The accreditation and approval of Inspectorate America...

75 FR 70936 - Accreditation and Approval of Intertek USA, Inc., as a Commercial Gauger and Laboratory

Federal Register 2010, 2011, 2012, 2013, 2014

2010-11-19

.... http:[sol][sol]cbp.gov[sol]xp[sol]cgov[sol]import[sol]operations-- support[sol]labs--scientific--svcs[sol]commercial--gaugers[sol] DATES: The accreditation and approval of Intertek USA, Inc., as...

Effect of content silver and heat treatment temperature on morphological, optical, and electrical properties of ITO films by sol-gel technique

NASA Astrophysics Data System (ADS)

Mirzaee, Majid; Dolati, Abolghasem

2014-09-01

Silver-doped indium tin oxide thin films were synthesized using sol-gel dip-coating technique. The influence of different silver-dopant contents and annealing temperature on the electrical, optical, structural, and morphological properties of the films were characterized by means of four-point probe, UV-Vis spectroscopy, X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), and X-ray photoelectron spectroscope (XPS). XRD analysis confirmed the formation of cubic bixbyte structure of In2O3 with silver nanoparticles annealed at 350 °C. XPS analysis showed that divalent tin transformed to tetravalent tin through oxidization, and silver nanoparticles embedded into ITO matrix covered with silver oxide shell, resulting in high quality nanocomposite thin films. The embedment of polyvinylpyrrolidone inhibited the growth of silver nanoparticles and ITO annealed at 350 °C. Delafossite structure of tin-doped AgInO2 was found at higher annealing temperatures. XRD analysis and FESEM micrographs showed that the optimum temperature to prevent the formation of AgInO2 is 350 °C. The embedment of silver particles (5-10 nm) from reduction of silver ion in ITO thin films improved the electrical conductivity and optical transmittance of ITO nanolayers. The lowest stable sheet resistance of 1,952 Ω/Sq for a 321 nm thick and an average optical transmittance of 91.8 % in the visible region with a band gap of 3.43 eV were achieved for silver-doping content of 0.04 M.

75 FR 70934 - U.S. Customs and Border Protection Accreditation and Approval of Intertek USA, Inc., as a...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-11-19

...:[sol][sol]cbp.gov[sol]xp[sol]cgov[sol]import[sol]operations-- support[sol]labs--scientific--svcs[sol]commercial--gaugers[sol]. DATES: The accreditation and approval of Intertek USA, Inc., as commercial gauger...

75 FR 70921 - Simon Property Group, Inc.; Analysis of Proposed Agreement Containing Consent Orders To Aid...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-11-19

... site, at http:[sol][sol]www.ftc.gov[sol]os[sol]publiccomments.shtm. Because comments will be made.../simonproperty . If this Notice appears at http:[sol][sol]www.regulations.gov[sol]search[sol]index.jsp, you may... regulations.gov forwards to it. You may also visit the FTC Web site at http:[sol][sol]www.ftc.gov[sol] to read...

Solvothermal-induced self-assembly of Fe2O3/GS aerogels for high Li-storage and excellent stability.

PubMed

Wang, Ronghua; Xu, Chaohe; Du, Meng; Sun, Jing; Gao, Lian; Zhang, Peng; Yao, Heliang; Lin, Chucheng

2014-06-12

A novel solvothermal-induced self-assembly approach, using colloid sol as precursor, is developed to construct monolithic 3D metal oxide/GS (graphene sheets) aerogels. During the solvothermal process, graphene oxide (GO) is highly reduced to GS and self-assembles into 3D macroscopic hydrogels, accompanying with in situ transformation of colloid sol to metal oxides. As a proof of concept, Fe2 O3 /GS aerogels are synthesized based on Fe(OH)3 sol, in which GS self-assemble into an interconnected macroporous framework and Fe2 O3 nanocrystals (20-50 nm) uniformly deposit on GS. Benefitting from the integration of macroporous structures, large surface area, high electrical conductivity, and good electrode homogeneity, the hybrid electrode manifests a superior rate capability (930, 660 and 520 mAh g(-1) at 500, 2000 and 4000 mA g(-1), respectively) and excellent prolonged cycling stability at high rates (733 mAh g(-1) during 1000 charge/discharge cycles at 2000 mA g(-1)), demonstrating its great potential for application in high performance lithium ion batteries. The work described here provides a versatile pathway to construct various graphene-based hybrid aerogels. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Sol-gel-derived hybrid materials multi-doped with rare-earth metal ions

NASA Astrophysics Data System (ADS)

Zelazowska, E.; Rysiakiewicz-Pasek, E.; Borczuch-Laczka, M.; Cholewa-Kowalska, K.

2012-06-01

Four different hybrid organic-inorganic materials based on TiO2-SiO2 matrices with organic additives and doped with rare-earth metal ions (III) from the group of europium, cerium, terbium, neodymium, dysprosium and samarium, were synthesized by sol-gel method. Tetraethyl orthosilicate, titanium (IV) isopropoxide and organic compounds, such as butyl acrylate, butyl methacrylate, ethyl acetoacetate, ethylene glycol dimethacrylate, ethyl acetate, propylene carbonate, organic solvents and certain inorganic salts were used in the synthesis. The inorganic part of the sols, which were used in the synthesis of all the hybrid materials, was prepared separately and then the organic parts were added. The materials obtained were aged for three weeks at room temperature and then heated in an electric oven for three hours at temperatures of 80 °C-150 °C. Scanning electron microscopy equipped with energy dispersive X-ray spectroscopy (SEM/EDX); X-ray diffraction (XRD); Fourier transform infrared spectroscopy (KBr technique); 29Si magic-angle spinning nuclear magnetic resonance; and fluorescence spectroscopy were used for the examination of morphology, microstructure and luminescence properties, respectively. Photoluminescence properties with relatively intense narrow emission lines of Tb, Eu, Dy, Nd, Sm respectively to the RE-ions doping, were observed for all the hybrid materials.

A Micro Oxygen Sensor Based on a Nano Sol-Gel TiO2 Thin Film

PubMed Central

Wang, Hairong; Chen, Lei; Wang, Jiaxin; Sun, Quantao; Zhao, Yulong

2014-01-01

An oxygen gas microsensor based on nanostructured sol-gel TiO2 thin films with a buried Pd layer was developed on a silicon substrate. The nanostructured titania thin films for O2 sensors were prepared by the sol-gel process and became anatase after heat treatment. A sandwich TiO2 square board with an area of 350 μm × 350 μm was defined by both wet etching and dry etching processes and the wet one was applied in the final process due to its advantages of easy control for the final structure. A pair of 150 nm Pt micro interdigitated electrodes with 50 nm Ti buffer layer was fabricated on the board by a lift-off process. The sensor chip was tested in a furnace with changing the O2 concentration from 1.0% to 20% by monitoring its electrical resistance. Results showed that after several testing cycles the sensor's output becomes stable, and its sensitivity is 0.054 with deviation 2.65 × 10−4 and hysteresis is 8.5%. Due to its simple fabrication process, the sensor has potential for application in environmental monitoring, where lower power consumption and small size are required. PMID:25192312

Division of Labor Among the Yeast Sol Proteins Implicated in tRNA Nuclear Export and Carbohydrate Metabolism

PubMed Central

Stanford, D. R.; Whitney, M. L.; Hurto, R. L.; Eisaman, D. M.; Shen, W.-C.; Hopper, A. K.

2004-01-01

SOL1, the founding member of the S. cerevisiae SOL family, was previously identified as a multi-copy suppressor of the los1 defect in tRNA-mediated nonsense suppression. Here we report that the four-member SOL family is not essential and that individual family members appear to have distinct functions. SOL1–SOL4 are homologous to genes encoding 6-phosphogluconolactonase (6Pgl) involved in the pentose phosphate pathway. Both Sol3p and Sol4p affect this activity. However, Sol4p does not act as a los1 multi-copy suppressor. In contrast, neither Sol1p nor Sol2p, both of which correct the los1 defect in nonsense suppression, possess detectable 6Pgl activity. Rather, Sol1p and Sol2p appear to function in tRNA nuclear export as sol1 and sol2 mutants possess elevated levels of nuclear tRNA. Members of the Sol protein family appear to have different subcellular distributions. Thus, Sol3p and Sol4p likely function in carbohydrate metabolism, while Sol1p and Sol2p appear to have roles in tRNA function and nuclear export, thereby defining an unusual protein family whose individual members are biochemically distinct and spatially dispersed. PMID:15454531

Division of labor among the yeast Sol proteins implicated in tRNA nuclear export and carbohydrate metabolism.

PubMed

Stanford, D R; Whitney, M L; Hurto, R L; Eisaman, D M; Shen, W-C; Hopper, A K

2004-09-01

SOL1, the founding member of the S. cerevisiae SOL family, was previously identified as a multi-copy suppressor of the los1 defect in tRNA-mediated nonsense suppression. Here we report that the four-member SOL family is not essential and that individual family members appear to have distinct functions. SOL1-SOL4 are homologous to genes encoding 6-phosphogluconolactonase (6Pgl) involved in the pentose phosphate pathway. Both Sol3p and Sol4p affect this activity. However, Sol4p does not act as a los1 multi-copy suppressor. In contrast, neither Sol1p nor Sol2p, both of which correct the los1 defect in nonsense suppression, possess detectable 6Pgl activity. Rather, Sol1p and Sol2p appear to function in tRNA nuclear export as sol1 and sol2 mutants possess elevated levels of nuclear tRNA. Members of the Sol protein family appear to have different subcellular distributions. Thus, Sol3p and Sol4p likely function in carbohydrate metabolism, while Sol1p and Sol2p appear to have roles in tRNA function and nuclear export, thereby defining an unusual protein family whose individual members are biochemically distinct and spatially dispersed.

Biocompatibility of sol-gel-derived titania-silica coated intramedullary NiTi nails.

PubMed

Muhonen, V; Kujala, S; Vuotikka, A; Aäritalo, V; Peltola, T; Areva, S; Närhi, T; Tuukkanen, J

2009-02-01

We investigated bone response to sol-gel-derived titania-silica coated functional intramedullary NiTi nails that applied a continuous bending force. Nails 26 mm in length, either straight or with a radius of curvature of 28 or 15 mm, were implanted in the cooled martensite form from a proximal to distal direction into the medullary cavity of the right femur in 40 Sprague-Dawley rats. Body temperature restored the austenite form, causing the curved implants to generate a bending force on the bone. The femurs were examined after 24 weeks. Bone length measurements did not reveal any bowing or shortening of the bone in the experimental groups. The results from histomorphometry demonstrated that the stronger bending force, together with sol-gel surface treatment, resulted in more bone deposition around the implant and the formation of significantly less fibrous tissue. Straight intramedullary nails, even those with a titania-silica coating, were poorly attached when compared to the implants with a curved austenite structure.

Encapsulation of Polymer Colloids in a Sol-Gel Matrix. Direct-Writing of Coassembling Organic-Inorganic Hybrid Photonic Crystals.

PubMed

Mikosch, Annabel; Kuehne, Alexander J C

2016-03-22

The spontaneous self-assembly of polymer colloids into ordered arrangements provides a facile strategy for the creation of photonic crystals. However, these structures often suffer from defects and insufficient cohesion, which result in flaking and delamination from the substrate. A coassembly process has been developed for convective assembly, resulting in large-area encapsulated colloidal crystals. However, to generate patterns or discrete deposits in designated places, convective assembly is not suitable. Here we experimentally develop conditions for direct-writing of coassembling monodisperse dye-doped polystyrene particles with a sol-gel precursor to form solid encapsulated photonic crystals. In a simple procedure the colloids are formulated in a sol-gel precursor solution, drop-cast on a flat substrate, and dried. We here establish the optimal parameters to form reproducible highly ordered photonic crystals with good optical performance. The obtained photonic crystals interact with light in the visible spectrum with a narrow optical stop-gap.

Cast-in-place, ambiently-dried, silica-based, high-temperature insulation

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

Cheng, Eric Jianfeng; Thompson, Travis; Salvador, James R.

A novel sol-gel chemistry approach was developed to enable the simple integration of a cast-in-place, ambiently-dried insulation into high temperature applications. The insulation was silica based, synthesized using methyltrimethoxysilane (MTMS) as the precursor. MTMS created a unique silica microstructure that was mechanically robust, macroporous, and superhydrophobic. To allow for casting into and around small, orthogonal features, zirconia fibers were added to increase stiffness and minimize contraction that could otherwise cause cracking during drying. Radiative heat transport was reduced by adding titania powder as an opacifier. To assess relevance to high temperature thermoelectric generator technology, a comprehensive set of materials characterizationsmore » were conducted. The silica gel was thermally stable, retained superhydrophobicity with a water contact angle > 150° , and showed a high electrical resistance > 1 GΩ, regardless of heating temperature (up to 600 °C in Ar for 4 h). In addition, it exhibited a Young's modulus ~3.7 MPa in room temperature and a low thermal conductivity < 0.08 W/m.K before and after heat treatment. Thus, based on the simplicity of the manufacturing process and optimized material properties, we believe this technology can act as an effective cast-in-place thermal insulation (CTI) for thermoelectric generators and myriad other applications requiring improved thermal efficiency.« less

Cast-in-place, ambiently-dried, silica-based, high-temperature insulation

DOE PAGES

Cheng, Eric Jianfeng; Thompson, Travis; Salvador, James R.; ...

2017-02-03

A novel sol-gel chemistry approach was developed to enable the simple integration of a cast-in-place, ambiently-dried insulation into high temperature applications. The insulation was silica based, synthesized using methyltrimethoxysilane (MTMS) as the precursor. MTMS created a unique silica microstructure that was mechanically robust, macroporous, and superhydrophobic. To allow for casting into and around small, orthogonal features, zirconia fibers were added to increase stiffness and minimize contraction that could otherwise cause cracking during drying. Radiative heat transport was reduced by adding titania powder as an opacifier. To assess relevance to high temperature thermoelectric generator technology, a comprehensive set of materials characterizationsmore » were conducted. The silica gel was thermally stable, retained superhydrophobicity with a water contact angle > 150° , and showed a high electrical resistance > 1 GΩ, regardless of heating temperature (up to 600 °C in Ar for 4 h). In addition, it exhibited a Young's modulus ~3.7 MPa in room temperature and a low thermal conductivity < 0.08 W/m.K before and after heat treatment. Thus, based on the simplicity of the manufacturing process and optimized material properties, we believe this technology can act as an effective cast-in-place thermal insulation (CTI) for thermoelectric generators and myriad other applications requiring improved thermal efficiency.« less

75 FR 70935 - Accreditation and Approval of Intertek USA, Inc., as a Commercial Gauger and Laboratory

Federal Register 2010, 2011, 2012, 2013, 2014

2010-11-19

... below for a complete listing of CBP approved gaugers and accredited laboratories. http:[sol][sol]cbp.gov[sol]xp[sol]cgov[sol]import[sol]operations-- support[sol]labs--scientific--svcs[sol]commercial--gaugers[sol]. DATES: The accreditation and approval of Intertek USA, Inc., as commercial gauger and laboratory...

75 FR 70935 - Accreditation and Approval of Intertek USA, Inc., as a Commercial Gauger and Laboratory

Federal Register 2010, 2011, 2012, 2013, 2014

2010-11-19

... listed below for a complete listing of CBP approved gaugers and accredited laboratories. http:[sol][sol]cbp.gov[sol]xp[sol]cgov[sol]import[sol]operations-- support[sol]labs--scientific--svcs[sol]commercial--gaugers[sol]. DATES: The accreditation and approval of Intertek USA, Inc., as commercial gauger and...

Pedestal and edge electrostatic turbulence characteristics from an XGC1 gyrokinetic simulation

NASA Astrophysics Data System (ADS)

Churchill, R. M.; Chang, C. S.; Ku, S.; Dominski, J.

2017-10-01

Understanding the multi-scale neoclassical and turbulence physics in the edge region (pedestal + scrape-off layer (SOL)) is required in order to reliably predict performance in future fusion devices. We explore turbulent characteristics in the edge region from a multi-scale neoclassical and turbulent XGC1 gyrokinetic simulation in a DIII-D like tokamak geometry, here excluding neutrals and collisions. For an H-mode type plasma with steep pedestal, it is found that the electron density fluctuations increase towards the separatrix, and stay high well into the SOL, reaching a maximum value of δ {n}e/{\\bar{n}}e˜ 0.18. Blobs are observed, born around the magnetic separatrix surface and propagate radially outward with velocities generally less than 1 km s-1. Strong poloidal motion of the blobs is also present, near 20 km s-1, consistent with E × B rotation. The electron density fluctuations show a negative skewness in the closed field-line pedestal region, consistent with the presence of ‘holes’, followed by a transition to strong positive skewness across the separatrix and into the SOL. These simulations indicate that not only neoclassical phenomena, but also turbulence, including the blob-generation mechanism, can remain important in the steep H-mode pedestal and SOL. Qualitative comparisons will be made to experimental observations.

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

Churchill, R. M.; Chang, C. S.; Ku, S.

Understanding the multi-scale neoclassical and turbulence physics in the edge region (pedestal + scrape-off layer (SOL)) is required in order to reliably predict performance in future fusion devices. We explore turbulent characteristics in the edge region from a multi-scale neoclassical and turbulent XGC1 gyrokinetic simulation in a DIII-D like tokamak geometry, here excluding neutrals and collisions. For an H-mode type plasma with steep pedestal, it is found that the electron density fluctuations increase towards the separatrix, and stay high well into the SOL, reaching a maximum value ofmore » $$\\delta {n}_{e}/{\\bar{n}}_{e}\\sim 0.18$$. Blobs are observed, born around the magnetic separatrix surface and propagate radially outward with velocities generally less than 1 km s –1. Strong poloidal motion of the blobs is also present, near 20 km s –1, consistent with E × B rotation. The electron density fluctuations show a negative skewness in the closed field-line pedestal region, consistent with the presence of 'holes', followed by a transition to strong positive skewness across the separatrix and into the SOL. These simulations indicate that not only neoclassical phenomena, but also turbulence, including the blob-generation mechanism, can remain important in the steep H-mode pedestal and SOL. Lastly, qualitative comparisons will be made to experimental observations.« less

Synthesis of superhydrophobic alumina membrane: Effects of sol-gel coating, steam impingement and water treatment

NASA Astrophysics Data System (ADS)

Ahmad, N. A.; Leo, C. P.; Ahmad, A. L.

2013-11-01

Ceramic membranes possess natural hydrophilicity thus tending to absorb water droplets. The absorption of water molecules on membrane surface reduces their application in filtration, membrane distillation, osmotic evaporation and membrane gas absorption. Fluoroalkylsilane (FAS) grafting allows the conversion of hydrophilic ceramic membranes into superhydrophobic thin layer, but it usually introduces a great increment of mass transfer resistance. In this study, superhydrophobic alumina membranes were synthesized by dip coating alumina support into sol-gel and grafted with the fluoroalkylsilane (FAS) named (heptadecafluoro-1,1,2,2-tetra hydrodecyl) triethoxysilane. Steam impingement and water treatment acted as additional steps to generate surface roughness on sol-gel and most importantly to reduce mass transfer resistance. Superhydrophobic alumina membrane with high water contact angle (158.4°) and low resistance (139.5 ± 24.9 G m-1) was successfully formed when the alumina membrane was dip coated into sol-gel for 7 s, treated with steam impingement for 1 min and immersed in hot water at 100 °C. However, the mass transfer resistance was greatly induced to 535.6 ± 23.5 G m-1 when the dip coating time was increased to 60 s. Long dip coating time contributes more on the blockage of porous structure rather than creates a thin film on the top of membrane surface. Reducing the pore size and porosity significantly due to increase of coating molecules deposited on the membrane. Steam impingement for 1 min promoted the formation of cones and valleys on the sol-gel, but the macro-roughness was destroyed when the steam impingement duration was extended to more than 3 min. The immersions of membranes into hot water at temperatures higher than 60 °C encouraged the formation of boehmite which enhances the formation of additional roughness and enlarges pore size greatly. Thus, this work showed that the formation of superhydrophobic alumina membrane with low resistance is influenced by three factors; sol-gel dip coating time, steam impingement time and temperature of water treatment. The optimum dip coating time could promote appropriate thickness of the sol-gel layer on the membrane support. The highest surface roughness and porosity could be created when the sol-gel layer was further treated with optimum steam impingement duration and immersed in hot water at 100 °C. The presence of appropriate sol-gel thickness can reduce the penetration of FAS during the grafting and reduce the membrane resistance.

Environmentally benign sol-gel antifouling and foul-releasing coatings.

PubMed

Detty, Michael R; Ciriminna, Rosaria; Bright, Frank V; Pagliaro, Mario

2014-02-18

Biofouling on ships and boats, characterized by aquatic bacteria and small organisms attaching to the hull, is an important global issue, since over 80000 tons of antifouling paint is used annually. This biofilm, which can form in as little as 48 hours depending on water temperature, increases drag on watercraft, which greatly reduces their fuel efficiency. In addition, biofouling can lead to microbially induced corrosion (MIC) due to H2S formed by the bacteria, especially sulfate-reducing bacteria. When the International Maritime Organization (IMO) international convention banned the use of effective but environmentally damaging coatings containing tributyl tin in 2008, the development of clean and effective antifouling systems became more important than ever. New nonbiocidal coatings are now in high demand. Scientists have developed new polymers, materials, and biocides, including new elastomeric coatings that they have obtained by improving the original silicone (polydimethylsiloxane) formulation patented in 1975. However, the high cost of silicones, especially of fluoropolymer-modified silicones, has generally prevented their large-scale diffusion. In 2009, traditional antifouling coatings using cuprous oxide formulated in copolymer paints still represented 95% of the global market volume of anti-fouling paints. The sol-gel nanochemistry approach to functional materials has emerged as an attractive candidate for creating low fouling surfaces due to the unique structure and properties of silica-based coatings and of hybrid inorganic-organic silicas in particular. Sol-gel formulations easily bind to all types of surfaces, such as steel, fiberglass, aluminum, and wood. In addition, they can cure at room temperature and form thin glassy coatings that are markedly different from thick silicone elastomeric foul-releasing coatings. Good to excellent performance against biofouling, low cure temperatures, enhanced and prolonged chemical and physical stability, ease of application, and the waterborne nature of sol-gel coatings all support the diffusion of these paints to efficiently reduce the accumulation of fouling layers on valued surfaces immersed in marine or fluvial waters. Furthermore, sol-gel glassy coatings are transparent and can be effectively applied to optical devices, windows, and solar panels used in lake, fluvial, or marine environments. Sol-gel technology is eminently versatile, and the first generation sol-gel paints have already shown good performance. Even so, vast opportunities still exist for chemists to develop novel sol-gel derived coatings to both prevent biofouling and enhance the hydrodynamic properties of boat and ship hulls. Moreover, researchers have prepared and applied multifunctional sol-gel coatings providing protection against both biofouling and corrosion. They have tested these in the marine environment with good preliminary results. In this Account, we discuss some of our new strategies for the controlled functionalization of surfaces for the development of efficient antifouling and foul-releasing systems and summarize the main achievements with biocidal and nonbiocidal sol-gel coatings. We conclude by giving insight into the marine coatings and sol-gel products markets, providing arguments to justify our conclusion that the sol-gel coatings technology is now a mature platform for the development of economically viable and environmentally friendly antifouling and foul-release formulations of enhanced performance.

A GIS application for assessing, mapping, and quantifying the social values of ecosystem services

USGS Publications Warehouse

Sherrouse, Benson C.; Clement, Jessica M.; Semmens, Darius J.

2011-01-01

As human pressures on ecosystems continue to increase, research involving the effective incorporation of social values information into the context of comprehensive ecosystem services assessments is becoming more important. Including quantified, spatially explicit social value metrics in such assessments will improve the analysis of relative tradeoffs among ecosystem services. This paper describes a GIS application, Social Values for Ecosystem Services (SolVES), developed to assess, map, and quantify the perceived social values of ecosystem services by deriving a non-monetary Value Index from responses to a public attitude and preference survey. SolVES calculates and maps the Value Index for social values held by various survey subgroups, as distinguished by their attitudes regarding ecosystem use. Index values can be compared within and among survey subgroups to explore the effect of social contexts on the valuation of ecosystem services. Index values can also be correlated and regressed against landscape metrics SolVES calculates from various environmental data layers. Coefficients derived through these analyses were applied to their corresponding data layers to generate a predicted social value map. This map compared favorably with other SolVES output and led to the addition of a predictive mapping function to SolVES for value transfer to areas where survey data are unavailable. A more robust application is being developed as a public domain tool for decision makers and researchers to map social values of ecosystem services and to facilitate discussions among diverse stakeholders involving relative tradeoffs among different ecosystem services in a variety of physical and social contexts.

Social Values for Ecosystem Services (SolVES): using GIS to include social values information in ecosystem services assessments

USGS Publications Warehouse

Sherrouse, B.C.; Semmens, D.J.

2010-01-01

Ecosystem services can be defined in various ways; simply put, they are the benefits provided by nature, which contribute to human well-being. These benefits can range from tangible products such as food and fresh water to cultural services such as recreation and esthetics. As the use of these benefits continues to increase, additional pressures are placed on the natural ecosystems providing them. This makes it all the more important when assessing possible tradeoffs among ecosystem services to consider the human attitudes and preferences that express underlying social values associated with their benefits. While some of these values can be accounted for through economic markets, other values can be more difficult to quantify, and attaching dollar amounts to them may not be very useful in all cases. Regardless of the processes or units used for quantifying such values, the ability to map them across the landscape and relate them to the ecosystem services to which they are attributed is necessary for effective assessments. To address some of the needs associated with quantifying and mapping social values for inclusion in ecosystem services assessments, scientists at the Rocky Mountain Geographic Science Center (RMGSC), in collaboration with Colorado State University, have developed a public domain tool, Social Values for Ecosystem Services (SolVES). SolVES is a geographic information system (GIS) application designed to use data from public attitude and preference surveys to assess, map, and quantify social values for ecosystem services. SolVES calculates and maps a 10-point Value Index representing the relative perceived social values of ecosystem services such as recreation and biodiversity for various groups of ecosystem stakeholders. SolVES output can also be used to identify and model relationships between social values and physical characteristics of the underlying landscape. These relationships can then be used to generate predicted Value Index maps for areas where survey data are not available. RMGSC will continue to develop more robust versions of SolVES by pursuing opportunities to work with land and resource managers as well as other researchers to apply SolVES to specific ecosystem management problems.

75 FR 73996 - Approval and Promulgation of State Air Quality Plans for Designated Facilities and Pollutants...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-11-30

...:[sol][sol]www.regulations.gov, including any personal information provided, unless the comment includes... http:[sol][sol]www.regulations.gov or e-mail. The http:[sol][sol]www.regulations.gov Web site is an... through http:[sol][sol]www.regulations.gov, your e-mail address will be automatically captured and...

Electrical properties of undoped zinc oxide nanostructures at different annealing temperature

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

Nasir, M. F., E-mail: babaibaik2002@yahoo.com; Zainol, M. N., E-mail: nizarzainol@yahoo.com; Hannas, M., E-mail: mhannas@gmail.com

This project has been focused on the electrical and optical properties respectively on the effect of Undoped zinc oxide (ZnO) thin films at different annealing temperature which is varied 400 °C, 450 °C, 500 °C, and 550 °C.Undoped ZnO solutions were deposited onto the glass substrates using sol-gel spin coating method. This project was involved with three phases, which are thin films preparation, deposition and characterization. The thin films were characterized using Current Voltage (I-V) measurement and UV-vis-NIR spectrophotometer for electrical properties and optical properties. The electrical properties show that the resistivity is the lowest at 500 °C which itsmore » resistivity is 5.36 × 10{sup 4} Ωcm{sup −1}. The absorption coefficient spectrum obtained from UV-Vis-NIR spectrophotometer measurement shows all films exhibit very low absorption in the visible (400-800 nm) and near infrared (NIR) (>800 nm) range but exhibit high absorption in the UV range.« less

Influence of Chromium Doping on Electrical and Magnetic Behavior of Nd0.5Sr0.5MnO3 System

NASA Astrophysics Data System (ADS)

Lalitha, G.; Pavan Kumar, N.; Venugopal Reddy, P.

2018-04-01

With a view to understand the influence of chromium doping at the Mn site on the electrical and magnetic behavior of the Nd0.5Sr0.5MnO3 manganite system, a series of samples were prepared by the citrate sol-gel route method. The samples were characterized structurally by XRD. A systematic investigation of electrical resistivity over a temperature range 5-300 K was carried out mainly to understand the magneto-transport behavior in these materials. Studies on the variation of magnetization with temperature over a temperature range 80-330 K were undertaken. Investigation of magnetization at different magnetic fields at two different temperatures, viz. 80 and 300 K, was also carried out. The results show that chromium doping gave typical electrical and magnetic properties. It has been concluded that the coexistence of charge ordered and ferromagnetic phases induced by chromium doping plays an important role in the low-temperature behavior of the system.

Synthesis and characterization of electrical conducting porous carbon structures based on resorcinol-formaldehyde

NASA Astrophysics Data System (ADS)

Najeh, I.; Ben Mansour, N.; Mbarki, M.; Houas, A.; Nogier, J. Ph.; El Mir, L.

2009-10-01

Electrical conducting carbon (ECC) porous structures were explored by changing the pyrolysis temperature of organic xerogel compounds prepared by sol-gel method from resorcinol-formaldehyde (RF) mixtures in acetone using picric acid as catalyst. The effect of this preparation parameter on the structural and electrical properties of the obtained ECCs was studied. The analysis of the obtained results revealed that the polymeric insulating xerogel phase was transformed progressively with pyrolysis temperature into carbon conducting phase; this means the formation of long continuous conducting path for charge carriers to move inside the structure with thermal treatment and the samples exhibited tangible percolation behaviour where the percolation threshold can be determined by pyrolysis temperature. The temperature-dependent conductivity of the obtained ECC structures shows a semi-conducting behaviour and the I( V) characteristics present a negative differential resistance. The results obtained from STM micrographs revealed that the obtained ECC structures consist of porous electrical conducting carbon materials.

Investigation of structural and electrical properties of La{sub 0.7}(Ba{sub 1-x}Ca{sub x}){sub 0.3}MnO{sub 3} compounds by sol-gel method

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

Winarsih, Suci; Kurniawan, Budhy, E-mail: bkuru07@gmail.com; Manaf, Azwar

2016-06-17

In this paper, we explored structural and electrical properties of La{sub 0.7}(Ba{sub 1-x}Ca{sub x}){sub 0.3}MnO{sub 3} (x = 0; 0.03; and 0.05) compounds. The general structure of perovskite manganites is AMnO{sub 3} (A= trivalent rare earth with divalent ion-doped). Average A-site cation size, external pressure, and the variance of the cation size σ{sup 2} are one of many factors that affected to magneto-transport properties of manganites as reported by others. In this work we focus only on the electrical properties in La{sub 0.7}Ba{sub 0.3}MnO{sub 3} Ca-doped compound which may influence crystal structure resulting resistivity phenomena under magnetic field influence. Allmore » samples were synthesized by sol-gel method from which fine powders were obtained. The X-ray powder diffraction pattern of powder materials shows that all samples are fully crystalline with a rhombohedral structure. Rietveld refinement shows that the presence of calcium has changed some crystal structural parameters such lattice parameter, Mn–O bond length, and Mn–O–Mn angles. The electrical resistivity of all synthesized materials investigated by four point probe method using Cryogenic Magnet in the temperature range of 50-300 K under influence a magnetic field shows resistivity temperature dependent. In fact presence of calcium has reduced the resistivity. It might occure because it has made an enhancement in the mobility of hopping electrons. The magnetic external field causes the resistivity decreased for all samples because host spin align by delocalizing the charge carries so electron itinerant through the lattice suggested by other authors. Both calcium dopant concentration and the applied external magnetic field shows strong correlation in reduction of resistivity.« less

Studies of structural, morphological, electrical, and magnetic properties of Mg-substituted Co-ferrite materials synthesized using sol-gel autocombustion method

NASA Astrophysics Data System (ADS)

Mammo, Tulu Wegayehu; Murali, N.; Sileshi, Yonatan Mulushoa; Arunamani, T.

2017-10-01

In this work,a nonmagnetic Mg partially substituted in CoFe2O4 was considered and has been shown to have an impact on structural, electrical and magnetic properties of ferrite materials with Co1-xMgxFe2O4 (x = 0, 0.25, 0.45, and 0.75) forms. Sol-gel synthesis route has been followed to synthesize these materials using citric acid as a fuel. Structural parameters were calculated from powder X-ray diffraction data. X-ray diffraction revealed that all the samples synthesized are pure cubic spinel structured materials with space group of Fd 3 ̅m and the lattice constant varying with Mg concentration. From the field emission scanning electron microscopy (FESEM) microstructure characterizations it has been shown that the synthesized materials are well defined crystalline structured with inhomogeneous grain sizes. Besides, the grain sizes were shown to decrease with increase of Mg-content. Fourier transform Infrared (FT-IR) characterization showed the cation vibrations and stretching of other groups in the wave number range of 400-4000 cm-1. The DC resistivity measurements showed an enhanced resistivity of the samples, in the order of 107 Ω cm, at the highest concentration of Mg. VSM magnetic properties analysis revealed that the Coercive force decreases with increase of Mg concentration whereas the saturation magnetization varies with Mg content.

Improving the optoelectronic properties of titanium-doped indium tin oxide thin films

NASA Astrophysics Data System (ADS)

Taha, Hatem; Jiang, Zhong-Tao; Henry, David J.; Amri, Amun; Yin, Chun-Yang; Mahbubur Rahman, M.

2017-06-01

The focus of this study is on a sol-gel method combined with spin-coating to prepare high-quality transparent conducting oxide (TCO) films. The structural, morphological, optical and electrical properties of sol-gel-derived pure and Ti-doped indium tin oxide (ITO) thin films were studied as a function of the concentration of the Ti (i.e. 0 at%, 2 at% and 4 at%) and annealing temperatures (150 °C-600 °C). FESEM measurements indicate that all the films are ˜350 nm thick. XRD analysis confirmed the cubic bixbyite structure of the polycrystalline indium oxide phase for all of the thin films. Increasing the Ti ratio, as well as the annealing temperature, improved the crystallinity of the films. Highly crystalline structures were obtained at 500 °C, with average grain sizes of about 50, 65 and 80 nm for Ti doping of 0 at%, 2 at% and 4 at%, respectively. The electrical and optical properties improved as the annealing temperature increased, with an enlarged electronic energy band gap and an optical absorption edge below 280 nm. In particular, the optical transmittance and electrical resistivity of the samples with a 4 at% Ti content improved from 87% and 7.10 × 10-4 Ω.cm to 92% and 1.6 × 10-4 Ω.cm, respectively. The conductivity, especially for the annealing temperature at 150 °C, is acceptable for many applications such as flexible electronics. These results demonstrate that unlike the more expensive and complex vacuum sputtering process, high-quality Ti-doped ITO films can be achieved by fast processing, simple wet-chemistry, and easy doping level control with the possibility of producing films with high scalability.

Structural and transport properties of NdCrO{sub 3} nanoceramics

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

Saha, Sujoy; Sakhya, Anup Pradhan; Sinha, T. P.

2013-02-05

Reitveld refinement of the room temperature powder X-ray diffraction profile of NdCrO{sub 3} (NCO) nanoceramics synthesized by sol-gel processing shows orthorhombic Pnma (D{sub 2h}{sup 16}) space group symmetry. The refined lattice parameters are a = 5.482(3) A, b = 7.689(4) A and c = 5.416(3) A. Transmission electron microscopy (TEM) of NCO shows that the average particle size is around 70 nm. The electrical transport property of NCO is investigated by both conductivity and electric modulus formalism. The electrical data is taken by a LCR meter in a temperature range from 303 K to 573 K and in a frequencymore » range from 42 Hz to 1.1 MHz. The ac conductivity follows a power law. The Cole-Cole plot of impedance at 303 K shows grain effect.« less

Experimental comparison of PV-smoothing controllers using distributed generators

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

Johnson, Jay Dean; Ellis, Abraham; Denda, Atsushi

The power output variability of photovoltaic systems can affect local electrical grids in locations with high renewable energy penetrations or weak distribution or transmission systems. In those rare cases, quick controllable generators (e.g., energy storage systems) or loads can counteract the destabilizing effects by compensating for the power fluctuations. Previously, control algorithms for coordinated and uncoordinated operation of a small natural gas engine-generator (genset) and a battery for smoothing PV plant output were optimized using MATLAB/Simulink simulations. The simulations demonstrated that a traditional generation resource such as a natural gas genset in combination with a battery would smooth the photovoltaicmore » output while using a smaller battery state of charge (SOC) range and extending the life of the battery. This paper reports on the experimental implementation of the coordinated and uncoordinated controllers to verify the simulations and determine the differences in the controllers. The experiments were performed with the PNM PV and energy storage Prosperity site and a gas engine-generator located at the Aperture Center at Mesa Del Sol in Albuquerque, New Mexico. Two field demonstrations were performed to compare the different PV smoothing control algorithms: (1) implementing the coordinated and uncoordinated controls while switching off a subsection of the PV array at precise times on successive clear days, and (2) comparing the results of the battery and genset outputs for the coordinated control on a high variability day with simulations of the coordinated and uncoordinated controls. It was found that for certain PV power profiles the SOC range of the battery may be larger with the coordinated control, but the total amp-hours through the battery-which approximates battery wear-will always be smaller with the coordinated control.« less

PV output smoothing using a battery and natural gas engine-generator.

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

Johnson, Jay Dean; Ellis, Abraham; Denda, Atsushi

2013-02-01

In some situations involving weak grids or high penetration scenarios, the variability of photovoltaic systems can affect the local electrical grid. In order to mitigate destabilizing effects of power fluctuations, an energy storage device or other controllable generation or load can be used. This paper describes the development of a controller for coordinated operation of a small gas engine-generator set (genset) and a battery for smoothing PV plant output. There are a number of benefits derived from using a traditional generation resource in combination with the battery; the variability of the photovoltaic system can be reduced to a specific levelmore » with a smaller battery and Power Conditioning System (PCS) and the lifetime of the battery can be extended. The controller was designed specifically for a PV/energy storage project (Prosperity) and a gas engine-generator (Mesa Del Sol) currently operating on the same feeder in Albuquerque, New Mexico. A number of smoothing simulations of the Prosperity PV were conducted using power data collected from the site. By adjusting the control parameters, tradeoffs between battery use and ramp rates could be tuned. A cost function was created to optimize the control in order to balance, in this example, the need to have low ramp rates with reducing battery size and operation. Simulations were performed for cases with only a genset or battery, and with and without coordinated control between the genset and battery, e.g., without the communication link between sites or during a communication failure. The degree of smoothing without coordinated control did not change significantly because the battery dominated the smoothing response. It is anticipated that this work will be followed by a field demonstration in the near future.« less

Growth of ZnO films in sol-gel electrophoretic deposition by different solvents

NASA Astrophysics Data System (ADS)

Hallajzadeh, Amir Mohammad; Abdizadeh, Hossein; Taheri, Mahtab; Golobostanfard, Mohammad Reza

2018-01-01

This article introduces a process to fabricate zinc oxide (ZnO) films through combining sol preparation and electrophoretic deposition (EPD). The experimental results have proved that the EPD process is a powerful route to fabricate ZnO films with desire thickness from stable colloidal suspension under a direct current (DC) electric field. In this method, ZnO sol is prepared by dissolving zinc acetate dehydrate (ZAD) as the main precursor and diethanolamine (DEA) as the additive in various solvents such as methanol (MeOH), ethanol (EtOH), and 2-proponal (2-PrOH). The deposition was performed under a constant voltage of 30 V for 2 min. Scanning electron microscopy (SEM), X-ray diffraction (XRD), and diffuse reflectance spectroscopy (DRS) were used to characterize ZnO films. XRD pattern of the ZnO film prepared by MeOH shows the highest degree of preferential orientation and this is mainly attributed to the higher dielectric constant of the MeOH which results in higher current density in electrophoretic deposit ion. The SEM cross section images also show that the thickness of the ZnO film enhances by decreasing the solvent chain length. According to SEM results, as the viscosity of the medium increased, more compact layers are formed, which can be attributed to the lower deposition rates in heavier alcohols.

75 FR 70905 - President's Export Council: Meeting of the President's Export Council

Federal Register 2010, 2011, 2012, 2013, 2014

2010-11-19

... Council will convene its next meeting via live webcast on the Internet at http:[sol][sol]whitehouse.gov[sol]live. FOR FURTHER INFORMATION CONTACT: J. Marc Chittum, President's Export Council, Room 4043...'s Export Council Web site at http:[sol][sol]trade.gov[sol]pec[sol]peccomments.asp; or Paper...

Sol-gel derived Al-Ga co-doped transparent conducting oxide ZnO thin films

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

Serrao, Felcy Jyothi, E-mail: jyothiserrao@gmail.com; Department of Physics, Karnataka Government Research centre SCEM, Mangalore, 575007; Sandeep, K. M.

2016-05-23

Transparent conducting ZnO doped with Al, Ga and co-doped Al and Ga (1:1) (AGZO) thin films were grown on glass substrates by cost effective sol-gel spin coating method. The XRD results showed that all the films are polycrystalline in nature and highly textured along the (002) plane. Enhanced grain size was observed in the case of AGZO thin films. The transmittance of all the films was more than 83% in the visible region of light. The electrical properties such as carrier concentration and mobility values are increased in case of AGZO compared to that of Al and Ga doped ZnOmore » thin films. The minimum resistivity of 2.54 × 10{sup −3} Ω cm was observed in AGZO thin film. The co-doped AGZO thin films exhibited minimum resistivity and high optical transmittance, indicate that co-doped ZnO thin films could be used in transparent electronics mainly in display applications.« less

Complex magnetic properties of TbMn{sub 1-x}Fe{sub x}O{sub 3} (x = 0.1 and 0.2) nanoparticles prepared by the sol-gel method

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

Das, A.; Chatterjee, S.; Das, D., E-mail: ddas@alpha.iuc.res.in

2016-05-23

TbMn{sub 1-x}Fe{sub x}O{sub 3} nanoparticles (NPs) with x = 0, 0.1 and 0.2 have been prepared by adopting the chemical sol-gel method. Phase identification and particle size estimation are done by XRD analysis. M-H measurements at 5 K indicate a complete ferromagnetic behaviour in the Fe-doped samples with large coercivity whereas the pristine sample shows presence of both ferromagnetic and antiferromagnetic orders. ZFC and FC magnetization curves of all samples show signature of antiferromagnetic ordering of both terbium and manganese magnetic moments along with a systematic shift of ordering temperatures with Fe substitution. {sup 57}Fe Mössbauer spectroscopic measurements of the Fe-dopedmore » samples at room temperature confirm the paramagnetic behaviour and reduction of electric field gradient around Fe probe atoms with increase of Fe concentration.« less

Fabrication of ZnO Thin Films by Sol-Gel Spin Coating and Their UV and White-Light Emission Properties

NASA Astrophysics Data System (ADS)

Kumar, Mirgender; Dubey, Sarvesh; Rajendar, Vanga; Park, Si-Hyun

2017-10-01

ZnO thin films have been fabricated by the sol-gel spin-coating technique and annealed under different conditions, and their ultraviolet (UV) and white-light emission properties investigated. Different ambient conditions including oxygen, nitrogen, zinc-rich nitrogen, and vacuum were used to tune the main properties of the ZnO thin films. The resistivity varied from the conductive to semi-insulating regime, and the luminescence emission from fairly intense UV to polychromatic. The emission intensity was also found to be a function of the annealing conditions. Possible routes to compensate the loss of emission characteristics are discussed. X-ray photoelectron spectroscopy (XPS) analysis was carried out to detect the chemical states of the zinc/oxygen species. The changes in the electrical and emission properties are explained based on annihilation/formation of inherent donor/acceptor-type defects. Such ZnO thin films could have potential applications in solid-state lighting.

Optical and electrical properties of sol-gel spin coated titanium dioxide thin films

NASA Astrophysics Data System (ADS)

Sahoo, Anusuya; Jayakrishnan, A. R.; Kamakshi, K.; Silva, J. P. B.; Sekhar, K. C.; Gomes, M. J. M.

2017-08-01

In this work; TiO2 thin films were deposited on glass and stainless steel substrates by sol-gel spin coating method. The films deposited on glass were annealed at different temperatures (Ta) in the range of 200 to 500 0C and that are deposited on steel substrate were annealed at 800 0C. The optical properties of TiO2 thin films were studied by using UV-VIS spectroscopy and photoluminescence (PL) spectroscopy. The transmittance on the average was found to ≥ 80 % and is found to sensitive to Ta. The PL spectra exhibited the strong emission band associated with band- to- band transition around 390 nm and the two weak bands at 480 and 510 nm associated to the oxygen defects and surface defects respectively. The current-voltage (I-V) characteristics of the Al/TiO2/steel capacitors were studied and analysed with application of various current mechanisms. Analysis reveals that the conduction in Al/TiO2/steel capacitors is governed by Poole-Frenkel mechanism.

Low-cost growth of magnesium doped gallium nitride thin films by sol-gel spin coating method

NASA Astrophysics Data System (ADS)

Amin, N. Mohd; Ng, S. S.

2018-01-01

Low-cost sol-gel spin coating growth of magnesium (Mg) doped gallium nitride (GaN) thin films with different concentrations of Mg was reported. The effects of the Mg concentration on the structural, surface morphology, elemental compositions, lattice vibrational, and electrical properties of the deposited films were investigated. X-ray diffraction results show that the Mg-doped samples have wurtzite structure with preferred orientation of GaN(002). The crystallite size decreases and the surface of the films with pits/pores were formed, while the crystalline quality of the films degraded as the Mg concentration increases from 2% to 6. %. All the Raman active phonon modes of the wurtzite GaN were observed while a broad peak attributed to the Mg-related lattice vibrational mode was detected at 669 cm-1. Hall effect results show that the resistivity of the thin films decreases while the hole concentration and hall mobility of thin films increases as the concentration of the Mg increases.

Photocatalytic degradation of methyl orange and bromophenol blue dyes in water using sol-gel synthesized TiO2 nanoparticles

NASA Astrophysics Data System (ADS)

Dhanalakshmi, J.; Pathinettam Padiyan, D.

2017-09-01

TiO2 nanoparticles were prepared by a sol-gel method using titanium tetra isopropoxide as a precursor. The structural, optical, morphological and electrical properties were studied by x-ray diffraction (XRD), diffuse reflectance spectroscopy (DRS), a high resolution scanning electron microscope (HR-SEM), a transmission electron microscope (TEM), Raman analysis, Photoluminescence (PL) and impedance spectroscopy. The XRD and Raman spectra revealed that the synthesized samples are in pure anatase phase with an average crystallite size of 18 nm. Photocatalytic activity of the TiO2 nanoparticles was investigated for the degradation of 10 ppm methyl orange (MO) and bromophenol blue (BPB) dye using 10 mg of catalyst. Anatase TiO2 exhibited the removal of 67.12% and 85.51% of MO and BPB, respectively, within 240 min. The photocatalytic degradation process is explained using pseudo second order kinetics and fits well with the higher correlation coefficient.

Conventional and two step sintering of PZT-PCN ceramics

NASA Astrophysics Data System (ADS)

Keshavarzi, Mostafa; Rahmani, Hooman; Nemati, Ali; Hashemi, Mahdieh

2018-02-01

In this study, PZT-PCN ceramic was made via sol-gel seeding method and effects of conventional sintering (CS) as well as two-step sintering (TSS) were investigated on microstructure, phase formation, density, dielectric and piezoelectric properties. First, high quality powder was achieved by seeding method in which the mixture of Co3O4 and Nb2O5 powder was added to the prepared PZT sol to form PZT-PCN gel. After drying and calcination, pyrochlore free PZT-PCN powder was synthesized. Second, CS and TSS were applied to achieve dense ceramic. The optimum temperature used for 2 h of conventional sintering was obtained at 1150 °C; finally, undesired ZrO2 phase formed in CS procedure was removed successfully with TSS procedure and dielectric and piezoelectric properties were improved compared to the CS procedure. The best electrical properties obtained for the sample sintered by TSS in the initial temperature of T 1 = 1200 °C and secondary temperature of T 2 = 1000 °C for 12 h.

Compare the phase transition properties of VO2 films from infrared to terahertz range

NASA Astrophysics Data System (ADS)

Liang, Shan; Shi, Qiwu; Huang, Wanxia; Peng, Bo; Mao, Zhenya; Zhu, Hongfu

2018-06-01

VO2 with reversible semiconductor-metal phase transition properties is particularly available for the application in smart opto-electrical devices. However, there are rare reports on comparing its phase transition properties at different ranges. In this study, the VO2 films are designed with the similar crystalline structure and stoichiometry, but different morphologies by inorganic and organic sol-gel methods, and their phase transition characteristics are compared both at infrared and terahertz range. The results indicate that the VO2 film prepared by inorganic sol-gel method shows more compact nanostructure. It results in larger resistivity change, infrared and terahertz switching ratio in the VO2 film. Moreover, it presents that the phase transition intensity of VO2 film in terahertz range is more sensitive to its microstructure. This work is helpful for understanding the susceptibility of terahertz switching properties of VO2 to its microstructure. And it can provide insights for the applications of VO2 in terahertz smart devices.

Zn1-xAlxO:Cu2O transparent metal oxide composite thin films by sol gel method

NASA Astrophysics Data System (ADS)

AlHammad, M. S.

2017-05-01

We have synthesized undoped zinc oxide (ZnO) and Cu2O doped Zn1-XAlXO (AZO; Al/Zn = 1.5 at.%) metal oxide films by sol-gel spin coating method. Atomic force microscopy results indicate that the Zn1-xAlxO:Cu2O is are formed form the fibers. The surface morphology of the films is found to depend on the concentration of Cu2O. The optical constants such as band gap, Urbach energy, refractive index, extinction coefficient and dielectric constants of the films were determined. The transmittance spectra shows that all the films are highly transparent. The study revealed that undoped ZnO film has direct bang gap of 3.29 eV and the optical band gap of films is increased with doping content. The hot probe measurements indicate that Zn1-xAlxO:Cu2O transparent metal oxide composite thin films exhibited p-type electrical conductivity.

High Quality 3D Photonics using Nano Imprint Lithography of Fast Sol-gel Materials.

PubMed

Bar-On, Ofer; Brenner, Philipp; Siegle, Tobias; Gvishi, Raz; Kalt, Heinz; Lemmer, Uli; Scheuer, Jacob

2018-05-18

A method for the realization of low-loss integrated optical components is proposed and demonstrated. This approach is simple, fast, inexpensive, scalable for mass production, and compatible with both 2D and 3D geometries. The process is based on a novel dual-step soft nano imprint lithography process for producing devices with smooth surfaces, combined with fast sol-gel technology providing highly transparent materials. As a concrete example, this approach is demonstrated on a micro ring resonator made by direct laser writing (DLW) to achieve a quality factor improvement from one hundred thousand to more than 3 million. To the best of our knowledge this also sets a Q-factor record for UV-curable integrated micro-ring resonators. The process supports the integration of many types of materials such as light-emitting, electro-optic, piezo-electric, and can be readily applied to a wide variety of devices such as waveguides, lenses, diffractive elements and more.

Characterization of zinc oxide thin film for pH detector

NASA Astrophysics Data System (ADS)

Hashim, Uda; Fathil, M. F. M.; Arshad, M. K. Md; Gopinath, Subash C. B.; Uda, M. N. A.

2017-03-01

This paper presents the fabrication process of the zinc oxide thin films for using to act as pH detection by using different PH solution. Sol-gel solution technique is used for preparing zinc oxide seed solution, followed by metal oxide deposition process by using spin coater on the silicon dioxide. Silicon dioxide layer is grown on the silicon wafer, then, ZnO seed solution is deposited on the silicon layer, baked, and annealing process carried on to undergo the characterization of its surface morphology, structural and crystalline phase. Electrical characterization is showed by using PH 4, 7, and 10 is dropped on the surface of the die, in addition, APTES solution is used as linker and also as a references of the electrical characterization.

Operation and maintenance of the Sol-Dance Building solar system. Final report

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

Gaultney, J.R.

1980-07-29

A 16,400 square foot general office facility has its primary heating provided by a flat plate solar system using hydronic storage and water-to-air transfer coils for distribution. Backup heat is provided by 10 individually controlled air source heat pumps ranging from 3 tons to 5 tons in capacity. These heat pumps also contain electric resistive elements for use during extremely low ambient temperatures. Cooling is also provided by the heat pumps. Each of the two buildings contains a separate domestic hot water system. Primary heat is provided by a closed loop solar unit with electric elements providing backup heat. Amore » 10,000 gallon black steel water tank provides heat storage.« less

Functional nucleic acid entrapment in sol-gel derived materials.

PubMed

Carrasquilla, Carmen; Brennan, John D

2013-10-01

Functional nucleic acids (FNAs) are single-stranded DNA or RNA molecules, typically generated through in vitro selection, that have the ability to act as receptors for target molecules (aptamers) or perform catalysis of a chemical reaction (deoxyribozymes and ribozymes). Fluorescence-signaling aptamers and deoxyribozymes have recently emerged as promising biological recognition and signaling elements, although little has been done to evaluate their potential for solid-phase assays, particularly with species made of RNA due to their lack of chemical stability and susceptibility to nuclease attack. Herein, we present a detailed overview of the methods utilized for solid-phase immobilization of FNAs using a sol-gel entrapment method that can provide protection from nuclease degradation and impart long-term chemical stability to the FNA reporter systems, while maintaining their signaling capabilities. This article will also provide a brief review of the results of such entrapment studies involving fluorescence-signaling versions of a DNA aptamer, selected RNA-cleaving deoxyribozymes, and two different RNA aptamers in a series of sol-gel derived composites, ranging from highly polar silica to hydrophobic methylsilsesquioxane-based materials. Given the ability to produce sol-gel derived materials in a variety of configurations, particularly as thin film coatings on electrodes, optical fibers, and other devices, this entrapment method should provide a useful platform for numerous solid-phase FNA-based biosensing applications. Copyright © 2013 Elsevier Inc. All rights reserved.

Pedestal and edge electrostatic turbulence characteristics from an XGC1 gyrokinetic simulation

DOE PAGES

Churchill, R. M.; Chang, C. S.; Ku, S.; ...

2017-08-30

Understanding the multi-scale neoclassical and turbulence physics in the edge region (pedestal + scrape-off layer (SOL)) is required in order to reliably predict performance in future fusion devices. We explore turbulent characteristics in the edge region from a multi-scale neoclassical and turbulent XGC1 gyrokinetic simulation in a DIII-D like tokamak geometry, here excluding neutrals and collisions. For an H-mode type plasma with steep pedestal, it is found that the electron density fluctuations increase towards the separatrix, and stay high well into the SOL, reaching a maximum value ofmore » $$\\delta {n}_{e}/{\\bar{n}}_{e}\\sim 0.18$$. Blobs are observed, born around the magnetic separatrix surface and propagate radially outward with velocities generally less than 1 km s –1. Strong poloidal motion of the blobs is also present, near 20 km s –1, consistent with E × B rotation. The electron density fluctuations show a negative skewness in the closed field-line pedestal region, consistent with the presence of 'holes', followed by a transition to strong positive skewness across the separatrix and into the SOL. These simulations indicate that not only neoclassical phenomena, but also turbulence, including the blob-generation mechanism, can remain important in the steep H-mode pedestal and SOL. Lastly, qualitative comparisons will be made to experimental observations.« less

Los1p, involved in yeast pre-tRNA splicing, positively regulates members of the SOL gene family.

PubMed

Shen, W C; Stanford, D R; Hopper, A K

1996-06-01

To understand the role of Los1p in pre-tRNA splicing, we sought los1 multicopy suppressors. We found SOL1 that suppresses both point and null LOS1 mutations. Since, when fused to the Ga14p DNA-binding domain, Los1p activates transcription, we tested whether Los1p regulates SOL1. We found that las1 mutants have depleted levels of SOL1 mRNA and Sol1p. Thus, LOS1 appears to positively regulate SOL1. SOL1 belongs to a multigene family with at least two additional members, SOL2 and SOL3. Sol proteins have extensive similarity to an unusual group of glucose-6-phosphate dehydrogenases. As the similarities are restricted to areas separate from the catalytic domain, these G6PDs may have more than one function. The SOL family appears to be unessential since cells with a triple disruption of all three SOL genes are viable. SOL gene disruptions negatively affect tRNA-mediated nonsense suppression and the severity increases with the number of mutant SOL genes. However, tRNA levels do not vary with either multicopy SOL genes or with SOL disruptions. Therefore, the Sol proteins affect tRNA expression/ function at steps other than transcription or splicing. We propose that LOS1 regulates gene products involved in tRNA expression/function as well as pre-tRNA splicing.

The effect of impeller type on silica sol formation in laboratory scale agitated tank

NASA Astrophysics Data System (ADS)

Nurtono, Tantular; Suprana, Yayang Ade; Latif, Abdul; Dewa, Restu Mulya; Machmudah, Siti; Widiyastuti, Winardi, Sugeng

2016-02-01

The multiphase polymerization reaction of the silica sol formation produced from silicic acid and potassium hydroxide solutions in laboratory scale agitated tank was studied. The reactor is equipped with four segmental baffle and top entering impeller. The inside diameter of reactor is 9 cm, the baffle width is 0.9 cm, and the impeller position is 3 cm from tank bottom. The diameter of standard six blades Rushton and three blades marine propeller impellers are 5 cm. The silicic acid solution was made from 0.2 volume fraction of water glass (sodium silicate) solution in which the sodium ion was exchanged by hydrogen ion from cation resin. The reactor initially filled with 286 ml silicic acid solution was operated in semi batch mode and the temperature was kept constant in 60 °C. The 3 ml/minute of 1 M potassium hydroxide solution was added into stirred tank and the solution was stirred. The impeller rotational speed was varied from 100 until 700 rpm. This titration was stopped if the solution in stirred tank had reached the pH of 10-The morphology of the silica particles in the silica sol product was analyzed by Scanning Electron Microscope (SEM). The size of silica particles in silica sol was measured based on the SEM image. The silica particle obtained in this research was amorphous particle and the shape was roughly cylinder. The flow field generated by different impeller gave significant effect on particle size and shape. The smallest geometric mean of length and diameter of particle (4.92 µm and 2.42 µm, respectively) was generated in reactor with marine propeller at 600 rpm. The reactor with Rushton impeller produced particle which the geometric mean of length and diameter of particle was 4.85 µm and 2.36 µm, respectively, at 150 rpm.

The effect of impeller type on silica sol formation in laboratory scale agitated tank

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

Nurtono, Tantular; Suprana, Yayang Ade; Latif, Abdul

2016-02-08

The multiphase polymerization reaction of the silica sol formation produced from silicic acid and potassium hydroxide solutions in laboratory scale agitated tank was studied. The reactor is equipped with four segmental baffle and top entering impeller. The inside diameter of reactor is 9 cm, the baffle width is 0.9 cm, and the impeller position is 3 cm from tank bottom. The diameter of standard six blades Rushton and three blades marine propeller impellers are 5 cm. The silicic acid solution was made from 0.2 volume fraction of water glass (sodium silicate) solution in which the sodium ion was exchanged by hydrogen ion from cationmore » resin. The reactor initially filled with 286 ml silicic acid solution was operated in semi batch mode and the temperature was kept constant in 60 °C. The 3 ml/minute of 1 M potassium hydroxide solution was added into stirred tank and the solution was stirred. The impeller rotational speed was varied from 100 until 700 rpm. This titration was stopped if the solution in stirred tank had reached the pH of 10-The morphology of the silica particles in the silica sol product was analyzed by Scanning Electron Microscope (SEM). The size of silica particles in silica sol was measured based on the SEM image. The silica particle obtained in this research was amorphous particle and the shape was roughly cylinder. The flow field generated by different impeller gave significant effect on particle size and shape. The smallest geometric mean of length and diameter of particle (4.92 µm and 2.42 µm, respectively) was generated in reactor with marine propeller at 600 rpm. The reactor with Rushton impeller produced particle which the geometric mean of length and diameter of particle was 4.85 µm and 2.36 µm, respectively, at 150 rpm.« less

The NEPRF (Naval Environmental Prediction Research Facility) Sunglint Pattern Calculation and Display System

DTIC Science & Technology

1989-01-01

CDATE,TN IQNX(1)=IDIFDTG(CIQNX,CDATE) SOL = FLOAT(IQNX(1))/24.DO/365.DO*360.DO*PI/180.DO SOLDEC=23.5DO*DSIN( SOL ) C C FIND THE LONGITUDE OF EQUATOR...CROSSING EQCX=LN IF(LH.EQ.1HW) EQCX=360.DO-EQCX C C FIND THE SOLAR LONGITUDE C READ (CTN,7004) SOL ,AMDA SOL = SOL +AMDA/60.DO SOL =DMOD(540.DO- SOL *15.DO,360.DO...AMDAxEQCX- SOL +360.DO AMDA=DMOD(AMDA, 360.DO) C WRITE (6,6000) IDATE WRITE (6,6001) HT,SIA IQNX(1)wIHE IF(SOL.LT.180.) GO TO 12 SOLz360.DO- SOL IQNX(1

Unilateral Muscle Overuse Causes Bilateral Changes in Muscle Fiber Composition and Vascular Supply

PubMed Central

Song, Yafeng; Forsgren, Sture; Liu, Jing-Xia; Yu, Ji-Guo; Stål, Per

2014-01-01

Unilateral strength training can cause cross-transfer strength effects to the homologous contralateral muscles. However, the impact of the cross-over effects on the muscle tissue is unclear. To test the hypothesis that unilateral muscle overuse causes bilateral alterations in muscle fiber composition and vascular supply, we have used an experimental rabbit model with unilateral unloaded overstrain exercise via electrical muscle stimulation (E/EMS). The soleus (SOL) and gastrocnemius (GA) muscles of both exercised (E) and contralateral non-exercised (NE) legs (n = 24) were morphologically analyzed after 1w, 3w and 6w of EMS. Non-exercised rabbits served as controls (n = 6). After unilateral intervention the muscles of both E and NE legs showed myositis and structural and molecular tissue changes that to various degrees mirrored each other. The fiber area was bilaterally smaller than in controls after 3w of E/EMS in both SOL (E 4420 and NE 4333 µm2 vs. 5183 µm2, p<0.05) and GA (E 3572 and NE 2983 µm2 vs. 4697 µm2, p<0.02) muscles. After 6w of E/EMS, the percentage of slow MyHCI fibers was lower than in controls in the NE legs of SOL (88.1% vs. 98.1%, p<0.009), while the percentage of fast MyHCIIa fibers was higher in the NE legs of GA (25.7% vs. 15.8%, p = 0.02). The number of capillaries around fibers in the E and NE legs was lower (SOL 13% and 15%, respectively, GA 25% and 23%, respectively, p<0.05) than in controls. The overall alterations were more marked in the fast GA muscle than in the slow SOL muscle, which on the other hand showed more histopathological muscle changes. We conclude that unilateral repetitive unloaded overuse exercise via EMS causes myositis and muscle changes in fiber type proportions, fiber area and fiber capillarization not only in the exercised leg, but also in the homologous muscles in the non-exercised leg. PMID:25545800

Mimicking nature: Self-strengthening properties in a dental adhesive.

PubMed

Song, Linyong; Ye, Qiang; Ge, Xueping; Misra, Anil; Spencer, Paulette

2016-04-15

Chemical and enzymatic hydrolysis provoke a cascade of events that undermine methacrylate-based adhesives and the bond formed at the tooth/composite interface. Infiltration of noxious agents, e.g. enzymes, bacteria, and so forth, into the spaces created by the defective bond will ultimately lead to failure of the composite restoration. This paper reports a novel, synthetic resin that provides enhanced hydrolytic stability as a result of intrinsic reinforcement of the polymer network. The behavior of this novel resin, which contains γ-methacryloxyproyl trimethoxysilane (MPS) as its Si-based compound, is reminiscent of self-strengthening properties found in nature. The efforts in this paper are focused on two essential aspects: the visible-light irradiation induced (photoacid-induced) sol-gel reaction and the mechanism leading to intrinsic self-strengthening. The FTIR band at 2840cm(-1) corresponding to CH3 symmetric stretch in -Si-O-CH3 was used to evaluate the sol-gel reaction. Results from the real-time FTIR indicated that the newly developed resin showed a limited sol-gel reaction (<5%) during visible-light irradiation, but after 48h dark storage, the reaction was over 65%. The condensation of methoxysilane mainly occurred under wet conditions. The storage moduli and glass transition temperature of the copolymers increased in wet conditions with the increasing MPS content. The cumulative amounts of leached species decreased significantly when the MPS-containing adhesive was used. The results suggest that the polymethacrylate-based network, which formed first as a result of free radical initiated polymerization, retarded the photoacid-induced sol-gel reaction. The sol-gel reaction provided a persistent, intrinsic reinforcement of the polymer network in both neutral and acidic conditions. This behavior led to enhanced mechanical properties of the dental adhesives under conditions that simulate the wet, oral environment. A self-strengthening dental adhesive system was developed through a dual curing process, which involves the free radical photopolymerization followed by slow hydrolysis and condensation (photoacid-induced sol-gel reaction) of alkoxylsilane groups. The concept of "living" photoacid-induced sol-gel reaction with visible-light irradiation was confirmed in the polymer. The sol-gel reaction was retarded by the polymethacrylate network, which was generated first; the network extended the life and retained the activity of silanol groups. The self-strengthening behavior was evaluated by monitoring the mechanical properties of the hybrid copolymers under wet conditions. The present research demonstrates the sol-gel reaction in highly crosslinked network as a potentially powerful strategy to prolong the functional lifetime of engineered biomaterials in wet environments. Copyright © 2016 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Microwave-Assisted Synthesis of High Dielectric Constant CaCu3Ti4O12 from Sol-Gel Precursor

NASA Astrophysics Data System (ADS)

Ouyang, Xin; Cao, Peng; Huang, Saifang; Zhang, Weijun; Huang, Zhaohui; Gao, Wei

2015-07-01

CaCu3Ti4O12 (CCTO) powders derived from sol-gel precursors were calcined and sintered via microwave radiation. The obtained CCTO powders were compared with that obtained via a conventional heating method. For microwave heating, 89.1 wt.% CCTO was achieved from the sol-gel precursor, after only 17 min at 950°C. In contrast, the conventional calcination method required 3 h to generate 87.6 wt.% CCTO content at 1100°C. In addition, the CCTO powders prepared through 17 min of microwave calcination exhibited a small particle size distribution of D50 = 3.826 μm. It was found that a lengthy hold time of 1 h by microwave sintering is required to obtain a high dielectric constant (3.14 × 103 at 102 Hz) and a reasonably low dielectric loss (0.161) in the sintered CCTO ceramic. Based upon the distinct microstructures, the dielectric responses of the CCTO samples sintered by different methods are attributed to space charge polarization and internal barrier layer capacitor mechanism.

The Sizing and Optimization Language, (SOL): Computer language for design problems

NASA Technical Reports Server (NTRS)

Lucas, Stephen H.; Scotti, Stephen J.

1988-01-01

The Sizing and Optimization Language, (SOL), a new high level, special purpose computer language was developed to expedite application of numerical optimization to design problems and to make the process less error prone. SOL utilizes the ADS optimization software and provides a clear, concise syntax for describing an optimization problem, the OPTIMIZE description, which closely parallels the mathematical description of the problem. SOL offers language statements which can be used to model a design mathematically, with subroutines or code logic, and with existing FORTRAN routines. In addition, SOL provides error checking and clear output of the optimization results. Because of these language features, SOL is best suited to model and optimize a design concept when the model consits of mathematical expressions written in SOL. For such cases, SOL's unique syntax and error checking can be fully utilized. SOL is presently available for DEC VAX/VMS systems. A SOL package is available which includes the SOL compiler, runtime library routines, and a SOL reference manual.

Method for protecting an electric generator

DOEpatents

Kuehnle, Barry W.; Roberts, Jeffrey B.; Folkers, Ralph W.

2008-11-18

A method for protecting an electrical generator which includes providing an electrical generator which is normally synchronously operated with an electrical power grid; providing a synchronizing signal from the electrical generator; establishing a reference signal; and electrically isolating the electrical generator from the electrical power grid if the synchronizing signal is not in phase with the reference signal.

Los1p, involved in yeast pre-tRNA splicing, positively regulates members of the SOL gene family

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

Shen, W.C.; Stanford, D.R.; Hopper, A.K.

1996-06-01

To understand the role of Los1p in pre-tRNA splicing, we sought los1 multicopy suppressors. We found SOL1 that suppresses both point and null LOS1 mutations. Since, when fused to the Gal4p DNA-binding domain, Los1p activates transcription, we tested whether Los1p regulates SOL1. We found that los1 mutants have depleted levels of SOL1 mRNA and Sol1p. Thus, LOS1 appears to positively regulate SOL1. SOL1 belongs to a multigene family with at least two additional members, SOL2 and SOL3. Sol proteins have extensive similarity to an unusual group of glucose-6-phosphate dehydrogenases (G6PDs). As the similarities are restricted to areas separate from themore » catalytic domain, these G6PDs may have more than one function. The SOL gene disruptions negatively affect tRNA-mediated nonsense suppression and the severity increases with the number of mutant SOL genes. However, tRNA levels do not vary with either multicopy SOL genes or with SOL disruptions. Therefore, the Sol proteins affect tRNA expression/function at steps other than transcription or splicing. We propose that LOS1 regulates gene products involved in tRNA expression/function as well as pre-tRNA splicing. 64 refs., 6 figs., 6 tabs.« less

75 FR 57956 - Draft Revision of the Federalwide Assurance

Federal Register 2010, 2011, 2012, 2013, 2014

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77 FR 30439 - Proposed Establishment of Class E Airspace; Apopka, FL

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2012-05-23

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76 FR 38585 - Proposed Establishment of Class E Airspace; Wilkes-Barre, PA

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2010-11-29

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78 FR 32213 - Proposed Amendment of Class E Airspace; Bedford, PA

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75 FR 73016 - Proposed Establishment of Class E Airspace; Kenbridge, VA

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2010-11-29

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Optical properties of doped sol-gel silica glasses

NASA Astrophysics Data System (ADS)

King, Terence A.

1994-01-01

Sol-gel optical composites were developed and characterized for potential applications in optics, lasers, nonlinear optics, and optoelectronics. Post-doped xerogels were index matched by in-situ polymerization of monomers to form inorganic-organic composites of low scatter and high optical quality. Characterization of the microstructure was made by visible and IR absorption and Raman Spectroscopy and optical quality by attenuation and scatter measurement. Doping techniques were optimized using hypercritical drying and vacuum impregnation and doping distribution monitored by laser-induced fluorescence. One-tenth wavelength surfaces were formed by novel optical polishing. Organic molecular dopants were tested in laser and nonlinear systems. Initial third harmonic generation and Z-scan measurements have shown the potential for saturable absorption and optical limiting.

Organo-metallic elements for associative information processing

NASA Astrophysics Data System (ADS)

Potember, Richard S.; Poehler, Theodore O.

1989-01-01

In the three years of the program we have: (1) built and tested a 4 bit element matrix device for possible use in high density content-addressable memories systems; (2) established a test and evaluation laboratory to examine optical materials for nonlinear effects, saturable absorption, harmonic generation and photochromism; (3) successfully designed, constructed and operated a codeposition processing system that enables organic materials to be deposited on a variety of substrates to produce optical grade coatings and films. This system is also compatible with other traditional microelectronic techniques; (4) used the sol-gel process with colloidal AgTCNQ to fabricate high speed photochromic switches; (5) develop and applied for patent coverage to make VO2 optical switching materials via the sol-gel processing using vanadium (IV) alkoxide compounds.

75 FR 70956 - Post Office Closing

Federal Register 2010, 2011, 2012, 2013, 2014

2010-11-19

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75 FR 70965 - Petition for Exemption; Summary of Petition Received

Federal Register 2010, 2011, 2012, 2013, 2014

2010-11-19

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Investigation of microstructure, electrical and photoluminescence behaviour of Ni-doped Zn0.96Mn0.04O nanoparticles: Effect of Ni concentration

NASA Astrophysics Data System (ADS)

Rajakarthikeyan, R. K.; Muthukumaran, S.

2017-07-01

ZnO, Zn0.96Mn0.04O and Ni-doped Zn0.96Mn0.04O nanoparticles with different Ni concentrations (0%, 2% and 4%) have been synthesized successfully by sol-gel method. The effects of Ni doping on the structural and optical properties were investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM), UV-visible spectroscopy, Fourier transform infrared (FTIR) spectroscopy and photoluminescence (PL) spectroscopy. The XRD pattern confirmed the existence of single phase wurtzite-like hexagonal structure throughout the Ni concentrations without any additional phases. The substitution of Ni created the lattice distortion due to the disparity of ionic radius between Zn and Ni which reduced the crystallite size. The microscopic images showed that the size of ZnO nanoparticles reduced by Ni-doping while the shape remains almost spherical/hexagonal type. The electrical conductivity found to be maximum at Ni = 2% due to the availability of more charge carriers generated by Ni. The decrease of electrical conductivity at higher doping (Ni = 4%) is due to the fact that the generation of more defects. The enhanced band gap from 3.73 eV (Ni = 0%) to 3.79 eV (Ni = 4%) by the addition of Ni explained by Burstein-Moss effect. The change in infra-red (IR) intensity and full width at half maximum (FWHM) corresponding to the frequency around defect states were caused by the difference in the bond lengths that occurs when Ni ion replaces Zn ion. The observed blue band emission from 474 nm to 481 nm is due to a radiative transition of an electron from the deep donar level of Zni to an acceptor level of neutral VZn and the origin of green band may be due to oxygen vacancies and intrinsic defects. The tuning of the band gap and the visible emission bands by Ni doping concluded that Ni-doped Zn0.96Mn0.04O is suitable for various nano-photo-electronics applications.

Light tuning DC and AC electrical properties of ZnO-rGO based hybrid nanocomposite film

NASA Astrophysics Data System (ADS)

Nath, Debarati; Mandal, S. K.; Deb, Debajit; Rakshit, J. K.; Dey, P.; Roy, J. N.

2018-03-01

We have investigated the electrical and optoelectrical properties of a zinc oxide (ZnO):reduced graphene oxide (rGO) nanocomposite film prepared through the sol gel process on a glass substrate under dark and illumination conditions of light. The bandgap of the composite film is decreased from the pure ZnO nanofilm due to the formation of a Zn-O-C bond in the composite film. The linear behavior in the Current-Voltage curve is attributed to Ohmic contact between ZnO and rGO grains. The photocurrent of the composite film is found to increase with an increase in light intensity having two different slopes, indicating an enhancement of the mobility of carriers and dissociation rate of excitons. The observed decrement of the impedance value with the intensity of light may be due to the flow of charge carriers and the presence of the light dependent relaxation process in the system. Nyquist plots have been fitted using a parallel combination of grain boundary resistances and grain boundary capacitance at different intensities of light. The relaxation frequency is observed to shift towards the high frequency regime. Carrier transit time has been calculated from relaxation frequency showing opposite behavior with the intensity of light. These results indicate the higher generations of photogenerated carriers at the interface between rGO and ZnO grains and an enhancement of the charge transport process due to the increment of the mobility of charge carriers in the system.

The preliminary SOL (Sizing and Optimization Language) reference manual

NASA Technical Reports Server (NTRS)

Lucas, Stephen H.; Scotti, Stephen J.

1989-01-01

The Sizing and Optimization Language, SOL, a high-level special-purpose computer language has been developed to expedite application of numerical optimization to design problems and to make the process less error-prone. This document is a reference manual for those wishing to write SOL programs. SOL is presently available for DEC VAX/VMS systems. A SOL package is available which includes the SOL compiler and runtime library routines. An overview of SOL appears in NASA TM 100565.

77 FR 22328 - Guidance for Industry on the Judicious Use of Medically Important Antimicrobial Drugs in Food...

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2011-06-30

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77 FR 35703 - Collection of Information Under Review by Office of Management and Budget

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2012-06-14

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2010-06-08

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Dielectric relaxation and electrical conductivity in Bi 5NbO 10 oxygen ion conductors prepared by a modified sol-gel process

NASA Astrophysics Data System (ADS)

Hou, Jungang; Vaish, Rahul; Qu, Yuanfang; Krsmanovic, Dalibor; Varma, K. B. R.; Kumar, R. V.

Crystalline Bi 5NbO 10 nanoparticles have been achieved through a modified sol-gel process using a mixture of ethylenediamine and ethanolamine as a solvent. The Bi 5NbO 10 nanoparticles were characterized by X-ray diffraction (XRD), differential scanning calorimetry/thermogravimetry (DSC/TG), Fourier transform infrared spectroscopy (FT-IR), transmission electron microscopy (TEM) and Raman spectroscopy. The results showed that well-dispersed 5-60 nm Bi 5NbO 10 nanoparticles were prepared through heat-treating the precursor at 650 °C and the high density pellets were obtained at temperatures lower than those commonly employed. The frequency and temperature dependence of the dielectric constant and the electrical conductivity of the Bi 5NbO 10 solid solutions were investigated in the 0.1 Hz to 1 MHz frequency range. Two distinct relaxation mechanisms were observed in the plots of dielectric loss and the imaginary part of impedance (Z″) versus frequency in the temperature range of 200-350 °C. The dielectric constant and the loss in the low frequency regime were electrode dependent. The ionic conductivity of Bi 5NbO 10 solid solutions at 700 °C is 2.86 Ω -1 m -1 which is in same order of magnitude for Y 2O 3-stabilized ZrO 2 ceramics at same temperature. These results suggest that Bi 5NbO 10 is a promising material for an oxygen ion conductor.

The gelation influence on diffusion and conductivity enhancement effect in renewable ionic gels based on a LMWG.

PubMed

Bielejewski, M; Rachocki, A; Kaszyńska, J; Tritt-Goc, J

2018-02-21

This paper reports the interdisciplinary study on molecular dynamics, ionic interactions and electrical conductivity in a quaternary ammonium salt (TMABr) ionogel based on a low molecular weight gelator (LMWG) in a wide range of electrolyte molar concentrations. The thermal scanning conductometry (TSC) was used to investigate the electric properties of the ionogels. The prepared TMABr/H 2 O/LMWG ionogel exhibits better ion transport properties than the dissociated TMA + cation in solution. The enhanced ionic conductivity effect (EICE) was observed in the concentration range of the TMABr salt up to 1 M. To investigate the transport properties of the TMA + cation and solvent molecules in the gel and sol phase, the NMR diffusiometry method was used. The field-cycling relaxometry method (FFC NMR) was applied to study the local motions of the electrolyte at the surface of the gelator matrix. On the basis of the obtained data, the higher ionic conductivity observed in the gel phase has been related to the microstructure of the gel matrix. The possible explanation for the origin of this effect has been given. The investigated system is a thermally reversible physical gel, all registered data were reproducible upon transforming the sample from gel to sol and back to the gel state, confirming the enhancement effect as a permanent property of the investigated ionogels. Therefore, the EICE has been proposed to be used as an internal sensor to monitor the condition of the ionogel phase, thus making them smart materials.

Dust Accumulation on Mars

NASA Technical Reports Server (NTRS)

2005-01-01

Since landing on Mars a year ago, NASA's pair of six-wheeled geologists have been constantly exposed to martian winds and dust. As a result, the Spirit rover has gradually experienced a slight decline in power as a thin layer of dust has accumulated on the solar panels, blocking some of the sunlight that is converted to electricity. In this enlarged image of a postage-stamp-size (3-centimeter-square, 1.2-inch-square) portion of one of Spirit's solar panels, a fine layer of martian dust coats electrical connections and metal surfaces. Individual silt grains or clumps of dust are visible where sediment has accumulated in crevices between solar cells and circuits. The upper right half of the image shows the edge of one of the rover's solar cells. The lower left half shows electrical wires bonded with silicon adhesive to the underlying composite surface; the circular abrasions are the result of sanding by hand on Earth. The braided wire is connected to a thermocouple used to measure temperature based on electrical resistance. Spirit took this image with its microscopic imager on martian day, or sol, 350 (Dec. 26, 2004).

Effect of Mn2+ doping on structural, electrical transport and dielectric properties of CoFe2O4 nanoparticles

NASA Astrophysics Data System (ADS)

Ansari, Mohd Mohsin Nizam; Khan, Shakeel; Bhargava, Richa; Ahmad, Naseem

2018-05-01

Manganese substituted cobalt ferrites, Co1-xMnxFe2O4 (0.0, 0.1, 0.2, 0.3 and 0.4) were successfully synthesized by sol-gel method. XRD analysis confirmed the formation of a single-phase cubic spinel structures having Fd-3m space group and crystallite size is found to be in the range of 12.9 - 15.5 nm. The lattice parameter increased from 8.4109 Å to 8.4531 Å with increasing Mn2+ ion doping. Dielectric constant (ɛ'), dielectric loss (tanδ) and ac conductivity (σac) were analyzed at room temperature as a function of frequency (42 Hz to 5 MHz) and the behavior is explained on the basis of Maxwell-Wagner interfacial polarization. DC electrical resistivity measurements were carried out by two-probe method. DC electrical resistivity decreases with increase in temperature confirms the semiconducting nature of the samples. Impedance spectroscopy method has been used to understand the conduction mechanism and the effect of grains and grain boundary on the electrical properties of the materials.

Electric Fields near RF Heating and Current Drive Antennas in Tore Supra Measured with Dynamic Stark Effect Spectroscopy*

NASA Astrophysics Data System (ADS)

Klepper, C. C.; Martin, E. H.; Isler, R. C.; Colas, L.; Hillairet, J.; Marandet, Y.; Lotte, Ph.; Colledani, G.; Martin, V.; Hillis, D. L.; Harris, J. H.; Saoutic, B.

2011-10-01

Computational models of the interaction between RF waves and the scrape-off layer plasma near ion cyclotron resonant heating (ICRH) and lower hybrid current drive launch antennas are continuously improving. These models mainly predict the RF electric fields produced in the SOL and, therefore, the best measurement for verification of these models would be a direct measurement of these electric fields. Both types of launch antennas are used on Tore Supra and are designed for high power (up to 4MW/antenna) and long pulse (> > 25s) operation. Direct, non-intrusive measurement of the RF electric fields in the vicinity of these structures is achieved by fitting spectral profiles of deuterium Balmer-alpha and Balmer-beta to a model that includes the dynamic, external-field Stark effect, as well as Zeeman splitting and Doppler broadening mechanisms. The measurements are compared to the mentioned, near-field region, RF antenna models. *Work supported in part by the US DOE under Contract No. DE-AC05-00OR22725 with UT-Battelle, LLC.

Field emission properties and strong localization effect in conduction mechanism of nanostructured perovskite LaNiO{sub 3}

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

Kamble, Ramesh B., E-mail: rbk.physics@coep.ac.in; Department of Physics, College of Engineering, Pune 411005, Maharashtra; Tanty, Narendra

2016-08-22

We report the potential field emission of highly conducting metallic perovskite lanthanum nickelate (LaNiO{sub 3}) from the nanostructured pyramidal and whisker shaped tips as electron emitters. Nano particles of lanthanum nickelate (LNO) were prepared by sol-gel route. Structural and morphological studies have been carried out. Field emission of LNO exhibited high emission current density, J = 3.37 mA/cm{sup 2} at a low threshold electric field, E{sub th} = 16.91 V/μm, obeying Fowler–Nordheim tunneling. The DC electrical resistivity exhibited upturn at 11.6 K indicating localization of electron at low temperature. Magnetoresistance measurement at different temperatures confirmed strong localization in nanostructured LNO obeying Anderson localization effect at low temperature.

Fabrication and characterization of lead-free BaTiO3 thin film for storage device applications

NASA Astrophysics Data System (ADS)

Sharma, Hakikat; Negi, N. S.

2018-05-01

The lead-free BaTiO3 (BT) thin film solution has been prepared by sol-gel method. The prepared solution spin coated on Pt/TiO2/SiO2/ Si substrate. The fabricated thin film was analyzed by XRD and Raman spectrometer for structural conformation. Uniformity of thin film was examined by Atomic force microscope (AFM). Thickness of the film was measured by cross sectional FESEM. Activation energies for both positive and negative biasing have been calculated from temperature dependent leakage current density as a function of electric field. For ferroelectric memory devices such as FRAM the hysteresis loop plays important role. Electric filed dependent polarization of BT thin film measured at different switching voltages. With increasing voltage maximum polarization increases.

Effect of co-doping process on topography, optical and electrical properties of ZnO nanostructured

NASA Astrophysics Data System (ADS)

Mohamed, R.; Mamat, M. H.; Malek, M. F.; Ismail, A. S.; Yusoff, M. M.; Syamsir, S. A.; Khusaimi, Z.; Rusop, M.

2018-05-01

We investigated of Undoped ZnO and Magnesium (Mg)-Aluminium (Al) co-doped Zinc Oxide (MAZO) nanostructured films were prepared by sol gel spin coating technique. The surface topography was analyzed using Atomic Force Microscopy (AFM). Based on the AFM results, Root Mean Square (RMS) of MAZO films have rougher surface compared to pure ZnO films. The optical and electrical properties of thin film samples were characterized using Uv-Vis spectroscopy and two point probes, current-voltage (I-V) measurements. The transmittance spectra for both thin samples was above 80% in the visible wavelength. The MAZO film shows the highest conductivity compared to pure ZnO films. This result indicates that the improvement of carrier mobility throughout doping process and possibly contribute by extra ion charge.

Apparatuses and methods for generating electric fields

DOEpatents

Scott, Jill R; McJunkin, Timothy R; Tremblay, Paul L

2013-08-06

Apparatuses and methods relating to generating an electric field are disclosed. An electric field generator may include a semiconductive material configured in a physical shape substantially different from a shape of an electric field to be generated thereby. The electric field is generated when a voltage drop exists across the semiconductive material. A method for generating an electric field may include applying a voltage to a shaped semiconductive material to generate a complex, substantially nonlinear electric field. The shape of the complex, substantially nonlinear electric field may be configured for directing charged particles to a desired location. Other apparatuses and methods are disclosed.

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Combining ray tracing and CFD in the thermal analysis of a parabolic dish tubular cavity receiver

NASA Astrophysics Data System (ADS)

Craig, Ken J.; Marsberg, Justin; Meyer, Josua P.

2016-05-01

This paper describes the numerical evaluation of a tubular receiver used in a dish Brayton cycle. In previous work considering the use of Computational Fluid Dynamics (CFD) to perform the calculation of the absorbed radiation from the parabolic dish into the cavity as well as the resulting conjugate heat transfer, it was shown that an axi-symmetric model of the dish and receiver absorbing surfaces was useful in reducing the computational cost required for a full 3-D discrete ordinates solution, but concerns remained about its accuracy. To increase the accuracy, the Monte Carlo ray tracer SolTrace is used to perform the calculation of the absorbed radiation profile to be used in the conjugate heat transfer CFD simulation. The paper describes an approach for incorporating a complex geometry like a tubular receiver generated using CFD software into SolTrace. The results illustrate the variation of CFD mesh density that translates into the number of elements in SolTrace as well as the number of rays used in the Monte Carlo approach and their effect on obtaining a resolution-independent solution. The conjugate heat transfer CFD simulation illustrates the effect of applying the SolTrace surface heat flux profile solution as a volumetric heat source to heat up the air inside the tube. Heat losses due to convection and thermal re-radiation are also determined as a function of different tube absorptivities.

Misdirection of Regenerating Axons and Functional Recovery Following Sciatic Nerve Injury in Rats

PubMed Central

Hamilton, Shirley K.; Hinkle, Marcus L.; Nicolini, Jennifer; Rambo, Lindsay N.; Rexwinkle, April M.; Rose, Sam J.; Sabatier, Manning J.; Backus, Deborah; English, Arthur W.

2013-01-01

Poor functional recovery found after peripheral nerve injury has been attributed to the misdirection of regenerating axons to reinnervate functionally inappropriate muscles. We applied brief electrical stimulation (ES) to the common fibular (CF) but not the tibial (Tib) nerve just prior to transection and repair of the entire rat sciatic nerve, to attempt to influence the misdirection of its regenerating axons. The specificity with which regenerating axons reinnervated appropriate targets was evaluated physiologically using compound muscle action potentials (M responses) evoked from stimulation of the two nerve branches above the injury site. Functional recovery was assayed using the timing of electromyography (EMG) activity recorded from the tibialis anterior (TA) and soleus (Sol) muscles during treadmill locomotion and kinematic analysis of hindlimb locomotor movements. Selective ES of the CF nerve resulted in restored M-responses at earlier times than in unstimulated controls in both TA and Sol muscles. Stimulated CF axons reinnervated inappropriate targets to a greater extent than unstimulated Tib axons. During locomotion, functional antagonist muscles, TA and Sol, were coactivated both in stimulated rats and in unstimulated but injured rats. Hindlimb kinematics in stimulated rats were comparable to untreated rats, but significantly different from intact controls. Selective ES promotes enhanced axon regeneration but does so with decreased fidelity of muscle reinnervation. Functional recovery is neither improved nor degraded, suggesting that compensatory changes in the outputs of the spinal circuits driving locomotion may occur irrespective of the extent of misdirection of regenerating axons in the periphery. PMID:21120925

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So, Why Sol-Mi? American Music Education

ERIC Educational Resources Information Center

Bennett, Peggy D.

2005-01-01

Walk into any primary grade music class in the U.S., and you will likely hear teacher and students singing a musical greeting, such as "Good morning boys and girls" (sol-mi-mi-sol-sol-mi) and the response "Good morning Miss Purdy" (sol-mi-mi-sol-mi-mi). Since about the 1970s, teachers have been beginning and ending music class for young children…

Analytical chemistry at the interface between materials science and biology

NASA Astrophysics Data System (ADS)

O'Brien, Janese Christine

This work describes several research efforts that lie at the new interfaces between analytical chemistry and other disciplines, namely materials science and biology. In the materials science realm, the search for new materials that may have useful or unique chromatographic properties motivated the synthesis and characterization of electrically conductive sol-gels. In the biology realm, the search for new surface fabrication schemes that would permit or even improve the detection of specific biological reactions motivated the design of miniaturized biological arrays. Collectively, this work represents some of analytical chemistry's newest forays into these disciplines. This dissertation is divided into six chapters. Chapter 1 is an introductory chapter that provides background information pertinent to several key aspects of the work contained in this dissertation. Chapter 2 describes the synthesis and characterization of electrically conductive sol-gels derived from the acid-catalyzed hydrolysis of a vanadium alkoxide. Specifically, this chapter describes our attempts to increase the conductivity of vanadium sol-gels by optimizing the acidic and drying conditions used during synthesis. Chapter 3 reports the construction of novel antigenic immunosensing platforms of increased epitope density using Fab'-SH antibody fragments on gold. Here, X-ray photoelectron spectroscopy (XPS), thin-layer cell (TLC) and confocal fluorescence spectroscopies, and scanning force microscopy (SFM) are employed to characterize the fragment-substrate interaction, to quantify epitope density, and to demonstrate fragment viability and specificity. Chapter 4 presents a novel method for creating and interrogating double-stranded DNA (dsDNA) microarrays suitable for screening protein:dsDNA interactions. Using the restriction enzyme ECoR1, we demonstrate the ability of the atomic force microscope (AFM) to detect changes in topography that result from the enzymatic cleavage of dsDNA microarrays containing the correct recognition sequence. Chapter 5 explores more fully the microarray fabrication process described in Chapter 4. Specifically, experiments characterizing the effect of deposition conditions on oligonucleotide topography and as well as those that describe array density optimization are presented. Chapter 6 presents general conclusions from the work recorded in this dissertation and speculates on its extension.

Spatiotemporal control of synergistic gel disintegration consisting of boroxole- and glyco-based polymers via photoinduced proton transfer.

PubMed

Kotsuchibashi, Yohei; Ebara, Mitsuhiro; Sato, Takeshi; Wang, Yinan; Rajender, Rajender; Hall, Dennis G; Narain, Ravin; Aoyagi, Takao

2015-02-12

We demonstrate here a local- and remote-control of gel disintegration by using photoinduced proton transfer chemistry of photoacid generator (PAG). The gels were prepared by simply mixing two polymers, poly(N-isopropylacrylamide-co-5-methacrylamido-1,2-benzoxaborole) (P(NIPAAm-co-MAAmBO)) and poly(3-gluconamidopropyl methacrylamide) (PGAPMA) via the synergistic interaction of benzoxaborole and diol groups. The o-nitrobenzaldehyde (o-NBA) was then loaded into the gel as a PAG. The benzoxaborole-diol interaction was successfully disintegrated upon UV irradiation due to the local pH decrease inside the gel. When the gel was irradiated to a specific gel region, the synergistic interactions were disintegrated only at the exposed region. Of special interest is that the whole material eventually transitioned from gel to sol state, as the generated protons diffused gradually toward the nonilluminated region. The ability of the proposed gel-sol transition system via photoinduced proton diffusion may be beneficial for not only prompt pH changes within the gel but also the design of predictive and programmable devices for drug delivery.

Identification, expression, and immuno-reactivity of Sol i 2 & Sol i 4 venom proteins of queen red imported fire ants, Solenopsis invicta Buren (Hymenoptera: Formicidae).

PubMed

Lockwood, Stephanie A; Haghipour-Peasley, Jilla; Hoffman, Donald R; Deslippe, Richard J

2012-10-01

We report on two low-molecular weight proteins that are stored in the venom of queen red imported fire ants (Solenopsis invicta). Translated amino acid sequences identified one protein to have 74.8% identity with the Sol i 2w worker allergen, and the other protein was found to have 96/97% identity with Sol i 4.01w/4.02w worker allergens. Both Sol i 2 and Sol i 4 queen and worker proteins were expressed using pEXP1-DEST vector in SHuffle™ T7 Express lysY Escherichia coli. Proteins were expressed at significant concentrations, as opposed to the μg/ml amounts by our previous expression methods, enabling further study of these proteins. Sol i 2q protein bound weakly to human IgE, sera pooled from allergic patients, whereas Sol i 2w, Sol i 4.01w, and Sol i 4q proteins bound strongly. Despite Sol i 2w and Sol i 2q proteins having 74.8% identity, the queen protein is less immuno-reactive than the worker allergen. This finding is consistent with allergic individuals being less sensitive to queen than worker venom. Copyright © 2012 Elsevier Ltd. All rights reserved.

"Hidden" O(2) and SO(2) symmetry in lepton mixing

NASA Astrophysics Data System (ADS)

Heeck, Julian; Rodejohann, Werner

2012-02-01

To generate the minimal neutrino Majorana mass matrix that has a free solar mixing angle and Δ m_{{^{text{sol}}}}^2 = 0 it suffices to implement an O(2) symmetry, or one of its subgroups SO(2), ZN ≥3, or DN ≥3. This O(2) generalizes the hidden {text{Z}}_{{^{{2}}}}^s of lepton mixing and leads in addition automatically to μ-τ symmetry. Flavor-democratic perturbations, as expected e.g. from the Planck scale, then result in tri-bimaximal mixing. We present a minimal model with three Higgs doublets implementing a type-I seesaw mechanism with a spontaneous breakdown of the symmetry, leading to large θ 13 and small Δ m_{{^{text{sol}}}}^2 = 0 due to the particular decomposition of the perturbations under μ-τ symmetry.

Viking-2 Seismometer Measurements on Mars: PDS Data Archive and Meteorological Applications

NASA Astrophysics Data System (ADS)

Lorenz, Ralph D.; Nakamura, Yosio; Murphy, James R.

2017-11-01

A data product has been generated and archived on the NASA Planetary Data System (Geosciences Node), which presents the seismometer readings of Viking Lander 2 in an easy-to-access form, for both the raw ("high rate") waveform records and the compressed ("event mode") amplitude and frequency records. In addition to the records themselves, a separate summary file for each instrument mode lists key statistics of each record together with the meteorological measurements made closest in time to the seismic record. This juxtaposition facilitates correlation of the seismometer instrument response to different meteorological conditions, or the selection of seismic data during which wind disturbances can be expected to be small. We summarize data quality issues and also discuss lander-generated seismic signals, due to operation of the sampling arm or other systems, which may be of interest for prospective missions to other bodies. We review wind-seismic correlation, the "Martian solar day (sol) 80" candidate seismic event, and identify the seismic signature of a probable dust devil vortex on sol 482 : the seismometer data allow an estimate of the peak wind, occurring between coarsely spaced meteorology measurements. We present code to generate the plots in this paper to illustrate use of the data product.

Enhancement of the inverted polymer solar cells via ZnO doped with CTAB

NASA Astrophysics Data System (ADS)

Sivashnamugan, Kundan; Guo, Tzung-Fang; Hsu, Yao-Jane; Wen, Ten-Chin

2018-02-01

A facile approach enhancing electron extraction in zinc oxide (ZnO) electron transfer interlayer and improving performance of bulk-heterojunction (BHJ) polymer solar cells (PSCs) by adding cetyltrimethylammonium bromide (CTAB) into sol-gel ZnO precursor solution was demonstrated in this work. The power conversion efficiency (PCE) has a 24.1% increment after modification. Our results show that CTAB can dramatically influence optical, electrical and morphological properties of ZnO electron transfer layer, and work as effective additive to enhance the performance of bulk- heterojunction polymer solar cells.

International Aerospace and Ground Conference on Lightning and Static Electricity (ICOLSE) (10th) and the Congres International Aeronautiq (17th) Held in Paris (France) on 10-13 June 1985

DTIC Science & Technology

1985-06-13

reelles de foudroiement et comparer ensuite les reponses obtenues ä celles issues de la simulation au sol, qui laisse subsister un doute quant a sa...but not be limited to, the follow- ing I tens: a) Management control b) Lightning zone identification c) Lightning coirpo.ient identification d...critical roles in functions such as stores management and fly-by-wire systems. Therefore, a great concern arises for preventing upset of these

Metal-silica sol-gel materials

NASA Technical Reports Server (NTRS)

Stiegman, Albert E. (Inventor)

2002-01-01

The present invention relates to a single phase metal-silica sol-gel glass formed by the co-condensation of a transition metal with silicon atoms where the metal atoms are uniformly distributed within the sol-gel glass as individual metal centers. Any transition metal may be used in the sol-gel glasses. The present invention also relates to sensor materials where the sensor material is formed using the single phase metal-silica sol-gel glasses. The sensor materials may be in the form of a thin film or may be attached to an optical fiber. The present invention also relates to a method of sensing chemicals using the chemical sensors by monitoring the chromatic change of the metal-silica sol-gel glass when the chemical binds to the sensor. The present invention also relates to oxidation catalysts where a metal-silica sol-gel glass catalyzes the reaction. The present invention also relates to a method of performing oxidation reactions using the metal-silica sol-gel glasses. The present invention also relates to organopolymer metal-silica sol-gel composites where the pores of the metal-silica sol-gel glasses are filled with an organic polymer polymerized by the sol-gel glass.

Visualizing and Quantifying Blob Characteristics on NSTX

NASA Astrophysics Data System (ADS)

Davis, William; Zweben, Stewart; Myra, James; D'Ippolito, Daniel; Ko, Matthew

2012-10-01

Understanding the radial motion of blob-filaments in the tokamak edge plasma is important since this motion can affect the width of the heat and particle scrape-off layer (SOL) [1]. High resolution (64x80), high speed (400,000 frames/sec) edge turbulence movies taken of the NSTX outer midplane separatrix region have recently been analyzed for blob motion. Regions of high light emission from gas puff imaging within a 25x30 cm cross-section were used to track blob-filaments in the plasma edge and into the SOL. Software tools have been developed for visualizing blob movement and automatically generating statistics of blob speed, shape, amplitude, size, and orientation; thousands of blobs have been analyzed for dozens of shots. The blob tracking algorithm and resulting database entries are explained in detail. Visualization tools also show how poloidal and radial motion change as blobs move through the scrape-off-layer (SOL), e.g. suggesting the influence of sheared flow. Relationships between blob size and velocity are shown for various types of plasmas and compared with simplified theories of blob motion. This work was supported by DOE Contract DE-AC02-09-CH11466. [4pt] [1] J.R. Myra et al, Phys. Plasmas 18, 012305 (2011)

Drift effects on the tokamak power scrape-off width

NASA Astrophysics Data System (ADS)

Meier, E. T.; Goldston, R. J.; Kaveeva, E. G.; Mordijck, S.; Rozhansky, V. A.; Senichenkov, I. Yu.; Voskoboynikov, S. P.

2015-11-01

Recent experimental analysis suggests that the scrape-off layer (SOL) heat flux width (λq) for ITER will be near 1 mm, sharply narrowing the planned operating window. In this work, motivated by the heuristic drift (HD) model, which predicts the observed inverse plasma current scaling, SOLPS-ITER is used to explore drift effects on λq. Modeling focuses on an H-mode DIII-D discharge. In initial results, target recycling is set to 90%, resulting in sheath-limited SOL conditions. SOL particle diffusivity (DSOL) is varied from 0.1 to 1 m2/s. When drifts are included, λq is insensitive to DSOL, consistent with the HD model, with λq near 3 mm; in no-drift cases, λq varies from 2 to 5 mm. Drift effects depress near-separatrix potential, generating a channel of strong electron heat convection that is insensitive to DSOL. Sensitivities to thermal diffusivities, plasma current, toroidal magnetic field, and device size are also assessed. These initial results will be discussed in detail, and progress toward modeling experimentally relevant high-recycling conditions will be reported. Supported by U.S. DOE Contract DE-SC0010434.

Effect of Sr substitution on the room temperature electrical properties of La1-xSrxFeO3 nano-crystalline materials

NASA Astrophysics Data System (ADS)

Kafa, C. A.; Triyono, D.; Laysandra, H.

2017-07-01

LaFeO3 is a material with Perovskite structure which electrical properties got investigated a lot, because as a p-type semiconductor it showed good gas sensing behavior through resistivity comparison. Sr doping on LaFeO3 is able to improve the electrical conductivity through structural modification. Using the Sr atoms doping concentration (x) from 0.1 to 0.4, La1-xSrxFeO3 nanocrystal pellets were synthesized using sol-gel method, followed by gradual heat treatment and uniaxial compaction. Structural analysis from XRD characterization shows that the structure of the materials is Orthorhombic Perovskite. The topography of the sample by SEM reveals grain and grain boundary existence with emerging agglomeration. The electrical properties of the material, as functions of frequency, were measured by Impedance Spectroscopy method using RLC meter. Through the Nyquist plot and Bode plot, the electrical conductivity of La1-xSrxFeO3 is contributed by grain and grain boundaries. It is reported that La0.6Sr0.4FeO3 sample has the most superior electrical conductivity of all samples, and the electrical permittivity of both La0.8Sr0.2FeO3 and La0.7Sr0.3FeO3 are the most stable.

The effect of microwave and conventional heating on a modified sol-gel derived biphasic calcium phosphate

NASA Astrophysics Data System (ADS)

Herradi, S.; Bouhazma, S.; Khaldi, M.; El Hachadi, A.; El Bali, B.; Lachkar, M.

2018-03-01

A facile sol-gel method was used to synthesize either hydroxyapatite (HA) or beta-tricalcium phosphate (β-TCP) as the major phase. Herein, we report, on the one hand, the effect of a very low maturation temperature on the final powder composition after drying step, and on the other hand, we compare the effect of calcination of this powder by microwave or electric furnace. It was found that microwave heating has led to the formation of hydroxyapatite phase upon 180°C for 20 minutes, however, XRD patterns show that the powder becomes less crystallized upon 220°C and amorphous upon 230°C. In contrast, furnace heating at 600°C and 700°C converts the as-synthesized powder to β-TCP as the major phase together with HA as the minor phase. This work shows the possibility to obtain the as-prepared BCP at much lower maturation temperature; it also gives an insight into the role, of either microwave or conventional heating, in controlling the ratio between HA and β-TCP in the sintered powder.

High Performance Perovskite Hybrid Solar Cells with E-beam-Processed TiOx Electron Extraction Layer.

PubMed

Meng, Tianyu; Liu, Chang; Wang, Kai; He, Tianda; Zhu, Yu; Al-Enizi, Abdullah; Elzatahry, Ahmed; Gong, Xiong

2016-01-27

Perovskite hybrid solar cells (pero-HSCs) have drawn great attention in the last 5 years. The efficiencies of pero-HSCs have been boosted from 3.8% to over 20%. However, one of the bottlenecks for commercialization of pero-HSCs is to make a high electrical conductive TiOx electron extraction layer (EEL). In this study, we report high performance pero-HSCs with TiOx EEL, where the TiOx EEL is fabricated by electron beam (e-beam) evaporation, which has been proved to be a well-developed manufacturing process. The resistance of the e-beam evaporated TiOx EEL is smaller than that of sol-gel processed TiOx EEL. Moreover, the dark current densities and interfacial charge carrier recombination of pero-HSCs incorporated with e-beam processed TiOx EEL is also smaller than that of pero-HSCs incorporated with sol-gel processed TiOx EEL. All these result in efficient pero-HSCs with high reproducibility. These results demonstrate that our method provides a simple and facile way to approach high performance pero-HSCs.

Resistive switching mechanism of ZnO/ZrO2-stacked resistive random access memory device annealed at 300 °C by sol-gel method with forming-free operation

NASA Astrophysics Data System (ADS)

Jian, Wen-Yi; You, Hsin-Chiang; Wu, Cheng-Yen

2018-01-01

In this work, we used a sol-gel process to fabricate a ZnO-ZrO2-stacked resistive switching random access memory (ReRAM) device and investigated its switching mechanism. The Gibbs free energy in ZnO, which is higher than that in ZrO2, facilitates the oxidation and reduction reactions of filaments in the ZnO layer. The current-voltage (I-V) characteristics of the device revealed a forming-free operation because of nonlattice oxygen in the oxide layer. In addition, the device can operate under bipolar or unipolar conditions with a reset voltage of 0 to ±2 V, indicating that in this device, Joule heating dominates at reset and the electric field dominates in the set process. Furthermore, the characteristics reveal why the fabricated device exhibits a greater discrete distribution phenomenon for the set voltage than for the reset voltage. These results will enable the fabrication of future ReRAM devices with double-layer oxide structures with improved characteristics.

Effect of both deposition temperature and indium doping on the properties of sol-gel dip-coated SnO2 films

NASA Astrophysics Data System (ADS)

Caglar, Mujdat; Atar, Kadir Cemil

2012-10-01

Using indium chloride as an In source, In-doped SnO2 films were fabricated by sol-gel method through dip-coating on borofloat glass substrates. The undoped SnO2 films were deposited in air between 400 and 600 °C to get optimum deposition temperature in terms of crystal quality and hence In-doped SnO2 films were deposited in air at 600 °C. The effect of both deposition temperature and In content on structural, morphological, optical and electrical properties was investigated. The crystalline structure and orientation of the films were investigated by X-ray diffraction (XRD) and surface morphology was studied by a field emission scanning electron microscope (FESEM). The compositional analysis of the films was confirmed by energy dispersive X-ray spectrometer (EDS). The absorption band edge of the SnO2 films shifted from 3.88 to 3.66 eV with In content. The van der Pauw method was used to measure the sheet resistance of the films. The sheet resistance was affected significantly by deposition temperature and In content.

Transport Properties and Magnetoresistance of La0.8Ca0.13Ag0.07MnO3 Perovskite Manganite Synthesized by Sol-Gel Method

NASA Astrophysics Data System (ADS)

Kurniawan, B.; Ruli, F.; Imaduddin, A.; Kamila, R.

2018-05-01

In this paper, we investigate the transport properties and magnetoresistance effect of La0.8Ca0.13Ag0.07MnO3 perovskite manganite synthesized by sol-gel method. The XRD pattern of the sample shows a rhombohedral perovskite structure with space group R3¯c. The EDX analysis confirms that the sample contains all expected chemical elements without any additional impurity. The temperature dependence of electrical resistivity was measured using a cryogenic magnetometer. The results show a metal-insulator transition temperature (TM-I ) at 280 K. The resistivity of the sample increases with an increase of temperature below TM-I . Theoretical analyses of the temperature dependence of resistivity suggest that the resistivity due to electron-electron scattering is predominant below TI-M. The resistivity of the sample decreases when applied magnetic field 1 T at a temperature range of 10 K to 300 K. The magnetoresistance of La0.8Ca0.13Ag0.07MnO3 emanates from spin-polarized tunneling process at the grain boundary.

Sol-gel synthesis and luminescent properties of red-emitting Y(P,V)O4:Eu(3+) phosphors.

PubMed

Zhang, Xinguo; Zhou, Fangxiang; He, Pei; Zhang, Min; Gong, Menglian

2016-02-01

Eu(3+)-activated Y(P,V)O4 phosphors were prepared by the EDTA sol-gel method, and the corresponding morphologies and luminescent properties were investigated. The sample particles were relatively spheroid with size of 2-3 µm and had a smooth surface. The excitation spectra for Y(P,V)O4:Eu(3+) consisted of three strong excitation bands in the 200-350 nm range, which were attributed to a Eu(3+)- O(2-) charge-transfer band and (1)A1-(1) T1/(1) T2 transitions in VO4(3-). The as-synthesized phosphors exhibited a highly efficient red luminescence at 613 nm due to the Eu(3+5) D0-(7) F2 electric dipole transition. With the increase in the V(5+)/P(5+) ratio, the luminescence intensity of the red phosphor under UV excitation was greatly improved due to enhanced VO4(3-) → Eu(3+) energy transfer. Copyright © 2015 John Wiley & Sons, Ltd.

An Evaluation of Structural, Topographic, Optical, and Temperature-Dependent Electrical Features of Sol-Gel Spin-Coated p-NiO/n-Si Heterojunction

NASA Astrophysics Data System (ADS)

Turgut, Güven; Duman, Songül; Özcelik, Fikriye Şeyma

2017-06-01

p-NiO/n-Si heterodiode was deposited with an easy and cheap sol-gel route using a spin coater. The XRD results revealed that NiO film had polycrystalline cubic bunsenite structure with (200) preferential direction. The AFM and SEM micrographs indicated that the film was composed of homogenously distributed nanoparticles on n-Si surface. The uniform scattering of Ni and O elements was also seen from EDX mapping pictures. The band gap value for NiO sample was found to be 3.74 eV. The current-voltage ( I- V) properties of Ag/p-NiO/n-Si heterojunction were inquired in the temperature range of 80 K to 300 K (-193 °C to 27 °C). The temperature coefficient of barrier height of the Ag/p-NiO/n-Si heterojunction was determined to be 2.6 meV/K. The I- V measurements showed that the barrier height of the heterojunction increased with an increment in the temperature.

Electrical and optical properties of sol-gel derived La modified PbTiO 3 thin films

NASA Astrophysics Data System (ADS)

Chopra, Sonalee; Sharma, Seema; Goel, T. C.; Mendiratta, R. G.

2004-09-01

Lanthanum modified lead titanate (Pb 1- xLa xTi 1- x/4 O 3) PLT x ( x=0.08 i.e. PLT8) sol-gel derived thin films have been prepared on indium tin oxide (ITO) coated glass and quartz substrates using lead acetate trihydrate, lanthanum acetate hydrate and titanium isopropoxide as precursors along with 2-methoxyethanol as solvent and acetic acid as catalyst by spin coating method. The microstructure and surface morphology of the films annealed at 650 °C have been studied by X-ray diffraction technique and atomic force microscope (AFM). XRD has shown a single phase with tetragonal structure and AFM images have confirmed a smooth and crack-free surface with low surface roughness. The dependence of leakage current on applied voltage show ohmic behavior at low field region with a space charge conduction mechanism at high fields. The wavelength dispersion curve of thin films obtained from the transmission spectrum of thin films show that the films have high optical transparency in the visible region.

Effect of Mo substitution on ferroelectric properties of Bi3.6Ho0.4Ti3O12 thin films prepared by sol-gel method

NASA Astrophysics Data System (ADS)

Guo, Dongyun; Wang, Chuanbin; Shen, Qiang; Zhang, Lianmeng; Li, Meiya; Liu, Jun

2008-12-01

The series of (Bi0.9Ho0.1)4-2x/3Ti3-xMoxO12 (BHTM) (x=0, 0.9%, 1.5%, 3.0%, and 6.0%) thin films on Pt/Ti/SiO2/Si substrates is prepared by sol-gel method, and the effect of Mo content on the microstructure and ferroelectric properties of these films are investigated. When the Mo content is not excessive, the BHTM films consisted of the single phase of Bi-layered Aurivillius phase. The B-site substitution with high-valent cation of Mo6+, in Bi3.6Ho0.4Ti3O12 films, enhanced the 2Pr (remanent polarization) and reduced the 2Ec (coercive field) of these films. The BHTM thin film with x =1.5% exhibited the best electrical properties with 2Pr of 48.4 μC/cm2, 2Ec of 263.5 kV/cm, dielectric constant of 391 (at 1 MHz), good insulting behavior, as well as the fatigue-free characteristic.

Thermally activated charge transport in modified tetragonal zirconia thin films prepared by sol-gel method

NASA Astrophysics Data System (ADS)

Aboulkacem, Khiali; Abdelkader, Ammari; Bediaf, Benrabah; Amar, Bouaza; Abdelmalek, Kharoubi; Hadj, Benhebal

2018-04-01

Films of Sn-doped ZrO2 were prepared using the sol-gel based dip-coating technique. The X-ray diffraction patterns showed a tetragonal structure with a preferential orientation along the (111) plane. The average grain size of the samples varies from 9.53 to 12.64 nm. Thermal analysis revealed endothermic peaks in the range 84-90 °C and exothermic peaks appearing in the range 489-531 °C. Fourier transform infrared (FTIR) spectra depicted bands located at 612 and 736 cm-1, which are attributed to stretching mode and asymmetric vibrations of Zr-O and O-Zr-O bonds respectively. All films exhibited high transmittance in the visible range above 60% and the optical band gap (E g) decreases from 4.085 to 4.061 eV. The impedance measurements show that the equivalent circuit of the samples is an R p C p where C p is the capacitance of the layer and R p its resistance. The electrical conductivity was found to follows an Arrhenius law with two activation energies.

Sol concentration effect on ZnO nanofibers photocatalytic activity synthesized by sol-gel dip coating method

NASA Astrophysics Data System (ADS)

Toubane, M.; Tala-Ighil, R.; Bensouici, F.; Bououdina, M.; Souier, M.; Liu, S.; Cai, W.; Iratni, A.

2017-03-01

ZnO thin films were deposited onto glass substrate by sol-gel dip coating method. The initial sol concentrations were varied from 0.2 to 0.5 M. Zinc acetate dihydrate, ethanol and Diethanolamine (DEA) were used as staring material, solvent and stabilizer respectively. The evolution of structural, optical properties and methylene blue (MB) photodegradation of the as-deposited films on sol concentration was investigated. Rietveld refinements of x-ray patterns reveal that all the as-prepared thin films have a Zincite-type structure with grain orientation along to c-axis. The strongest sol concentration is favorable for the highest crystallization quality. However, the high preferred orientation factor (POF) occurs for 0.3 M sol concentration. The field emission scanning electron microscopy observations reveals nanofibrous morphology with different lengths. The nanofibers density increases with increasing sols concentrations until forming a flower-like morphology. The EDS analysis confirms the high purity of the as-deposited ZnO films. It is found that all films present good transparency greater than 95% in the visible range; the optical band gap is slightly reduced with the increase in sol concentration. The photocatalytic degradation is enhanced by 90% with the sol concentration. The K app rate reaction increased with increasing sol concentration. The films stability is found to slightly decrease after the third cycle, especially for 0.5 M sol concentration.

Thickening compositions containing xanthomonas gum and hydroxyalkyl ether of guar gum

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

Jordan, W.A.

1973-07-24

Natural and synthetic gums have been used as thickeners for foods, coatings, paints, dyes, explosive slurries, oil-well fluids, and many other applications. Thickening compositions are described which consist of xanthomonas gum and hydroxyalkyl ether of guar gum and are suitable for use in explosive slurries. Aqueous sols of xanthomonas gum are plastic in nature and exhibit higher gel strengths than sols of other gums. Aqueous sols of hydroxyalkyl ether of guar are almost Newtonian and exhibit little or no gel strength. Aqueous sols of the thickening compositions of the present invention are plastic in character. At certain concentrations of themore » thickening compositions in aqueous sols, the sols have higher gel strengths than can be obtained from xanthomonas gum alone. At certain concentrations, the aqueous sols containing the thickening compositions exhibit greater viscosity differentials than do sols containing xanthomonas gum alone. In addition, the aqueous sols exhibit a greater drop in viscosity as the thickening composition concentration is reduced than do aqueous sols of xanthomonas gum alone.(5 claims)« less

Wireless Electrical Device Using Open-Circuit Elements Having No Electrical Connections

NASA Technical Reports Server (NTRS)

Taylor, Bryant Douglas (Inventor); Woodard, Stanley E. (Inventor)

2012-01-01

A wireless electrical device includes an electrically unconnected electrical conductor and at least one electrically unconnected electrode spaced apart from the electrical conductor. The electrical conductor is shaped for storage of an electric field and a magnetic field. In the presence of a time-varying magnetic field, the electrical conductor so-shaped resonates to generate harmonic electric and magnetic field responses. Each electrode is at a location lying within the magnetic field response so-generated and is constructed such that a linear movement of electric charges is generated in each electrode due to the magnetic field response so-generated.

Results From Mars Show Electrostatic Charging of the Mars Pathfinder Sojourner Rover

NASA Technical Reports Server (NTRS)

Kolecki, Joseph C.; Siebert, Mark W.

1998-01-01

Indirect evidence (dust accumulation) has been obtained indicating that the Mars Pathfinder rover, Sojourner, experienced electrostatic charging on Mars. Lander camera images of the Sojourner rover provide distinctive evidence of dust accumulation on rover wheels during traverses, turns, and crabbing maneuvers. The sol 22 (22nd Martian "day" after Pathfinder landed) end-of-day image clearly shows fine red dust concentrated around the wheel edges with additional accumulation in the wheel hubs. A sol 41 image of the rover near the rock "Wedge" (see the next image) shows a more uniform coating of dust on the wheel drive surfaces with accumulation in the hubs similar to that in the previous image. In the sol 41 image, note particularly the loss of black-white contrast on the Wheel Abrasion Experiment strips (center wheel). This loss of contrast was also seen when dust accumulated on test wheels in the laboratory. We believe that this accumulation occurred because the Martian surface dust consists of clay-sized particles, similar to those detected by Viking, which have become electrically charged. By adhering to the wheels, the charged dust carries a net nonzero charge to the rover, raising its electrical potential relative to its surroundings. Similar charging behavior was routinely observed in an experimental facility at the NASA Lewis Research Center, where a Sojourner wheel was driven in a simulated Martian surface environment. There, as the wheel moved and accumulated dust (see the following image), electrical potentials in excess of 100 V (relative to the chamber ground) were detected by a capacitively coupled electrostatic probe located 4 mm from the wheel surface. The measured wheel capacitance was approximately 80 picofarads (pF), and the calculated charge, 8 x 10(exp -9) coulombs (C). Voltage differences of 100 V and greater are believed sufficient to produce Paschen electrical discharge in the Martian atmosphere. With an accumulated net charge of 8 x 10(exp -9) C, and average arc time of 1 msec, arcs can also occur with estimated arc currents approaching 10 milliamperes (mA). Discharges of this magnitude could interfere with the operation of sensitive electrical or electronic elements and logic circuits. Sojourner rover wheel tested in laboratory before launch to Mars. Before launch, we believed that the dust would become triboelectrically charged as it was moved about and compacted by the rover wheels. In all cases observed in the laboratory, the test wheel charged positively, and the wheel tracks charged negatively. Dust samples removed from the laboratory wheel averaged a few ones to tens of micrometers in size (clay size). Coarser grains were left behind in the wheel track. On Mars, grain size estimates of 2 to 10 mm were derived for the Martian surface materials from the Viking Gas Exchange Experiment. These size estimates approximately match the laboratory samples. Our tentative conclusion for the Sojourner observations is that fine clay-sized particles acquired an electrostatic charge during rover traverses and adhered to the rover wheels, carrying electrical charge to the rover. Since the Sojourner rover carried no instruments to measure this mission's onboard electrical charge, confirmatory measurements from future rover missions on Mars are desirable so that the physical and electrical properties of the Martian surface dust can be characterized. Sojourner was protected by discharge points, and Faraday cages were placed around sensitive electronics. But larger systems than Sojourner are being contemplated for missions to the Martian surface in the foreseeable future. The design of such systems will require a detailed knowledge of how they will interact with their environment. Validated environmental interaction models and guidelines for the Martian surface must be developed so that design engineers can test new ideas prior to cutting hardware. These models and guidelines cannot be validated without actual flighata. Electrical charging of vehicles and, one day, astronauts moving across the Martian surface may have moderate to severe consequences if large potential differences develop. The observations from Sojourner point to just such a possibility. It is desirable to quantify these results. The various lander/rover missions being planned for the upcoming decade provide the means for doing so. They should, therefore, carry instruments that will not only measure vehicle charging but characterize all the natural and induced electrical phenomena occurring in the environment and assess their impact on future missions.

75 FR 39710 - Postal Classification Change

Federal Register 2010, 2011, 2012, 2013, 2014

2010-07-12

.... ADDRESSES: Submit comments electronically via the Commission's Filing Online system at http:[sol][sol]www... the Commission's Web site (http:[sol][sol]www.prc.gov). Proposed edits to the draft Mail...

Preparation and characterization of TiO2 coated Fe nanofibers for electromagnetic wave absorber.

PubMed

Jang, Dae-Hwan; Song, Hanbok; Lee, Young-In; Lee, Kun-Jae; Kim, Ki Hyeon; Oh, Sung-Tag; Lee, Sang-Kwan; Choa, Yong-Ho

2011-01-01

Recently, electromagnetic interference (EMI) and electromagnetic compatibility (EMC) have become serious problems due to the growth of electronic device and next generation telecommunication. It is necessary to develop new electromagnetic wave absorbing material to overcome the limitation of electromagnetic wave shielding materials. The EMI attenuation is normally related to magnetic loss and dielectric loss. Therefore, magnetic material coating dielectric materials are required in this reason. In this study, TiO2 coated Fe nanofibers were prepared to improve their properties for electromagnetic wave absorption. Poly(vinylpyrrolidone) (PVP) and Iron (III) nitrate nonahydrate (Fe(NO3)3 x 9H2O) were used as starting materials for the synthesis of Fe oxide nanofibers. Fe oxide nanofibers were prepared by electrospinning in an electric field and heat treatment. TiO2 layer was coated on the surface of Fe oxide nanofibers using sol-gel process. After the reduction of TiO2 coated Fe oxide nanofibers, Fe nanofibers with a TiO2 coating layer of about 10 nm were successfully obtained. The morphology and structure of fibers were characterized by SEM, TEM, and XRD. In addition, the absorption properties of TiO2 coated Fe nanofibers were measured by network analyzer.

Investigations of Particle Transport in the Texas Helimak

NASA Astrophysics Data System (ADS)

Taylor, E. I.; Rowan, W. L.; Gentle, K. W.; Huang, H.; Williams, C. B.

2016-10-01

The correlation between electrostatic turbulence and particle flux is investigated in a simple magnetic torus, the Helimak. The Helimak is an experimental realization of a sheared cylindrical slab that generates and heats a plasma with microwaves at 2.45 GHz and confines it in a helical magnetic field. Although it is MHD stable, the plasma is always in a nonlinearly saturated state of microturbulence. The causes of this turbulence are diverse and it is thought that it is either due to drift wave instabilities or interchange instabilites. The local particle flux is estimated over most of the plasma cross section by measuring the particle source using filtered cameras. Plasma flow along the field lines is physically similar to SOL flows in tokamaks. It is significant and can be measured directly as well as inferred from asymmetries in the electron density. The cross field transport due to electrostatic turbulence is measured as the cross correlation of radial electric field fluctuations with electron density fluctuations with the data acquired using Langmuir probes. This material is based upon work supported by the U.S. Department of Energy Office of Science, Office of Fusion Energy Sciences under Award Number DE-FG02-04ER54766.

BaTiO3/PVDF Nanocomposite Film with High Energy Storage Density

NASA Astrophysics Data System (ADS)

Wang, Xiaohui

2016-03-01

A gradated multilayer BaTiO3/poly(vinylidenefluoride) thin film structure is presented to achieve both a higher breakdown strength and a superior energy-storage capability. Key to the process is the sequential deposition of uniform dispersions of the single component source, which generate a blended PVDF-BTO-PVDF structure prior to full evaporation of solvent, and thermal treatment of the dielectric. The result is like sandwich structure with partial 0-3 character. The central layer designed to provide the high electric displacement, is composed of high volume fraction 6-10 nm BTO nanocrystals produced by a TEG-sol method. The outer layers of the structure are predominantly PVDF, with a significantly lower volume fraction of BTO, taking advantage of the higher dielectric strength for pure PVDF at the electrode-nanocomposite interface. The film is mechanically flexible, and can be removed from the substrate, with total thicknesses in the range 1.2 - 1.5 μm. Parallel plate capacitance devices improved dielectric performances, compared to reported values for BTO-PVDF 0-3 nanocomposites, with a maximal discharged energy density of 19.4J/cm3 and dielectric breakdown strengths of up to 495 kV/mm.

Overview of the TCV tokamak program: scientific progress and facility upgrades

NASA Astrophysics Data System (ADS)

Coda, S.; Ahn, J.; Albanese, R.; Alberti, S.; Alessi, E.; Allan, S.; Anand, H.; Anastassiou, G.; Andrèbe, Y.; Angioni, C.; Ariola, M.; Bernert, M.; Beurskens, M.; Bin, W.; Blanchard, P.; Blanken, T. C.; Boedo, J. A.; Bolzonella, T.; Bouquey, F.; Braunmüller, F. H.; Bufferand, H.; Buratti, P.; Calabró, G.; Camenen, Y.; Carnevale, D.; Carpanese, F.; Causa, F.; Cesario, R.; Chapman, I. T.; Chellai, O.; Choi, D.; Cianfarani, C.; Ciraolo, G.; Citrin, J.; Costea, S.; Crisanti, F.; Cruz, N.; Czarnecka, A.; Decker, J.; De Masi, G.; De Tommasi, G.; Douai, D.; Dunne, M.; Duval, B. P.; Eich, T.; Elmore, S.; Esposito, B.; Faitsch, M.; Fasoli, A.; Fedorczak, N.; Felici, F.; Février, O.; Ficker, O.; Fietz, S.; Fontana, M.; Frassinetti, L.; Furno, I.; Galeani, S.; Gallo, A.; Galperti, C.; Garavaglia, S.; Garrido, I.; Geiger, B.; Giovannozzi, E.; Gobbin, M.; Goodman, T. P.; Gorini, G.; Gospodarczyk, M.; Granucci, G.; Graves, J. P.; Guirlet, R.; Hakola, A.; Ham, C.; Harrison, J.; Hawke, J.; Hennequin, P.; Hnat, B.; Hogeweij, D.; Hogge, J.-Ph.; Honoré, C.; Hopf, C.; Horáček, J.; Huang, Z.; Igochine, V.; Innocente, P.; Ionita Schrittwieser, C.; Isliker, H.; Jacquier, R.; Jardin, A.; Kamleitner, J.; Karpushov, A.; Keeling, D. L.; Kirneva, N.; Kong, M.; Koubiti, M.; Kovacic, J.; Krämer-Flecken, A.; Krawczyk, N.; Kudlacek, O.; Labit, B.; Lazzaro, E.; Le, H. B.; Lipschultz, B.; Llobet, X.; Lomanowski, B.; Loschiavo, V. P.; Lunt, T.; Maget, P.; Maljaars, E.; Malygin, A.; Maraschek, M.; Marini, C.; Martin, P.; Martin, Y.; Mastrostefano, S.; Maurizio, R.; Mavridis, M.; Mazon, D.; McAdams, R.; McDermott, R.; Merle, A.; Meyer, H.; Militello, F.; Miron, I. G.; Molina Cabrera, P. A.; Moret, J.-M.; Moro, A.; Moulton, D.; Naulin, V.; Nespoli, F.; Nielsen, A. H.; Nocente, M.; Nouailletas, R.; Nowak, S.; Odstrčil, T.; Papp, G.; Papřok, R.; Pau, A.; Pautasso, G.; Pericoli Ridolfini, V.; Piovesan, P.; Piron, C.; Pisokas, T.; Porte, L.; Preynas, M.; Ramogida, G.; Rapson, C.; Rasmussen, J. Juul; Reich, M.; Reimerdes, H.; Reux, C.; Ricci, P.; Rittich, D.; Riva, F.; Robinson, T.; Saarelma, S.; Saint-Laurent, F.; Sauter, O.; Scannell, R.; Schlatter, Ch.; Schneider, B.; Schneider, P.; Schrittwieser, R.; Sciortino, F.; Sertoli, M.; Sheikh, U.; Sieglin, B.; Silva, M.; Sinha, J.; Sozzi, C.; Spolaore, M.; Stange, T.; Stoltzfus-Dueck, T.; Tamain, P.; Teplukhina, A.; Testa, D.; Theiler, C.; Thornton, A.; Tophøj, L.; Tran, M. Q.; Tsironis, C.; Tsui, C.; Uccello, A.; Vartanian, S.; Verdoolaege, G.; Verhaegh, K.; Vermare, L.; Vianello, N.; Vijvers, W. A. J.; Vlahos, L.; Vu, N. M. T.; Walkden, N.; Wauters, T.; Weisen, H.; Wischmeier, M.; Zestanakis, P.; Zuin, M.; the EUROfusion MST1 Team

2017-10-01

The TCV tokamak is augmenting its unique historical capabilities (strong shaping, strong electron heating) with ion heating, additional electron heating compatible with high densities, and variable divertor geometry, in a multifaceted upgrade program designed to broaden its operational range without sacrificing its fundamental flexibility. The TCV program is rooted in a three-pronged approach aimed at ITER support, explorations towards DEMO, and fundamental research. A 1 MW, tangential neutral beam injector (NBI) was recently installed and promptly extended the TCV parameter range, with record ion temperatures and toroidal rotation velocities and measurable neutral-beam current drive. ITER-relevant scenario development has received particular attention, with strategies aimed at maximizing performance through optimized discharge trajectories to avoid MHD instabilities, such as peeling-ballooning and neoclassical tearing modes. Experiments on exhaust physics have focused particularly on detachment, a necessary step to a DEMO reactor, in a comprehensive set of conventional and advanced divertor concepts. The specific theoretical prediction of an enhanced radiation region between the two X-points in the low-field-side snowflake-minus configuration was experimentally confirmed. Fundamental investigations of the power decay length in the scrape-off layer (SOL) are progressing rapidly, again in widely varying configurations and in both D and He plasmas; in particular, the double decay length in L-mode limited plasmas was found to be replaced by a single length at high SOL resistivity. Experiments on disruption mitigation by massive gas injection and electron-cyclotron resonance heating (ECRH) have begun in earnest, in parallel with studies of runaway electron generation and control, in both stable and disruptive conditions; a quiescent runaway beam carrying the entire electrical current appears to develop in some cases. Developments in plasma control have benefited from progress in individual controller design and have evolved steadily towards controller integration, mostly within an environment supervised by a tokamak profile control simulator. TCV has demonstrated effective wall conditioning with ECRH in He in support of the preparations for JT-60SA operation.

Impact of grain size and structural changes on magnetic, dielectric, electrical, impedance and modulus spectroscopic characteristics of CoFe2O4 nanoparticles synthesized by honey mediated sol-gel combustion method

NASA Astrophysics Data System (ADS)

Singh Yadav, Raghvendra; Kuřitka, Ivo; Vilcakova, Jarmila; Havlica, Jaromir; Masilko, Jiri; Kalina, Lukas; Tkacz, Jakub; Švec, Jiří; Enev, Vojtěch; Hajdúchová, Miroslava

2017-12-01

In this work CoFe2O4 spinel ferrite nanoparticles were synthesized by honey mediated sol-gel combustion method and further annealed at higher temperature 500 °C, 700 °C, 900 °C and 1100 °C. The synthesized spinel ferrite nanoparticles is investigated by x-ray diffraction, Raman spectroscopy, Fourier transform infrared (FTIR) spectroscopy, thermogravimetric analysis/differential scanning calorimetry (TGA/DSC), field emission scanning electron microscopy, x-ray photoelectron spectroscopy and vibrating sample magnetometer. The x-ray diffraction study reveals face-centered cubic spinel cobalt ferrite crystal phase formation. The crystallite size and lattice parameter are increased with annealing temperature. Raman and Fourier transform infrared spectra also confirm spinel ferrite crystal structure of synthesized nanoparticles. The existence of cation at octahedral and tetrahedral site in cobalt ferrite nanoparticles is confirmed by x-ray photoelectron spectroscopy. Magnetic measurement shows increased saturation magnetization 74.4 emu g-1 at higher annealing temperature 1100 °C, high coercivity 1347.3 Oe at lower annealing temperature 500 °C, and high remanent magnetization 32.3 emu g-1 at 900 °C annealing temperature. The magnetic properties of synthesized ferrite nanoparticles can be tuned by adjusting sizes through annealing temperature. Furthermore, the dielectric constant and ac conductivity shows variation with frequency (1-107 Hz), grain size and cation redistribution. The modulus spectroscopy study reveals the role of bulk grain and grain boundary towards the resistance and capacitance. The cole-cole plots in modulus formalism also well support the electrical response of nanoparticles originated from both grain and grain boundaries. The dielectric, electrical, magnetic, impedance and modulus spectroscopic characteristics of synthesized CoFe2O4 spinel ferrite nanoparticles demonstrate the applicability of these nanoparticles for magnetic recording, memory devices and for microwave applications.

Studying Structural, Optical, Electrical, and Sensing Properties of Nanocrystalline SnO2:Cu Films Prepared by Sol-Gel Method for CO Gas Sensor Application at Low Temperature

NASA Astrophysics Data System (ADS)

Al-Jawad, Selma M. H.; Elttayf, Abdulhussain K.; Saber, Amel S.

Nanocrystalline SnO2 and SnO2:Cu thin films derived from SnCl2ṡ2H2O precursors have been prepared on glass substrates using sol-gel dip-coating technique. The deposited film was 300±20nm thick and the films were annealed in air at 500∘C for 1h. Structural, optical and sensing properties of the films were studied under different preparation conditions, such as Cu-doping concentration of 2%, 4% and 6wt.%. X-ray diffraction studies show the polycrystalline nature with tetragonal rutile structure of SnO2 and Cu:SnO2 thin films. The films have highly preferred orientation along (110). The crystallite size of the prepared samples reduced with increasing Cu-doping concentrations and the addition of Cu as dopants changed the structural properties of the thin films. Surface morphology was determined through scanning electron microscopy and atomic force microscopy. Results show that the particle size decreased as doping concentration increased. The films have moderate optical transmission (up to 82.4% at 800nm), and the transmittance, absorption coefficient and energy gap at different Cu-doping concentration were measured and calculated. Results show that Cu-doping decreased the transmittance and energy gap whereas it increased the absorption coefficient. Two peaks were noted with Cu-doping concentration of 0-6wt.%; the first peak was positioned exactly at 320nm ultraviolet emission and the second was positioned at 430-480nm. Moreover, emission bands were noticed in the photoluminescence spectra of Cu:SnO2. The electrical properties of SnO2 films include DC electrical conductivity, showing that the films have two activation energies, namely, Ea1 and Ea2, which increase as Cu-doping concentration increases. Cudoped nanocrystalline SnO2 gas-sensing material has better sensitivity to CO gas compared with pure SnO2.

The SOL-2/Neto Auxiliary Protein Modulates the Function of AMPA-Subtype Ionotropic Glutamate Receptors

PubMed Central

Wang, Rui; Mellem, Jerry E.; Jensen, Michael; Brockie, Penelope J.; Walker, Craig S.; Hoerndli, Frédéric J.; Madsen, David M.; Maricq, Andres V.

2012-01-01

Summary The neurotransmitter glutamate mediates excitatory synaptic transmission by gating ionotropic glutamate receptors (iGluRs). AMPA receptors (AMPARs), a subtype of iGluR, are strongly implicated in synaptic plasticity, learning and memory. We previously discovered two classes of AMPAR auxiliary proteins in C. elegans that modify receptor kinetics and thus change synaptic transmission. Here, we have identified another auxiliary protein, SOL-2, a CUB-domain protein that associates with both the related auxiliary subunit SOL-1 and with the GLR-1 AMPAR. In sol-2 mutants, behaviors dependent on glutamatergic transmission are disrupted, GLR-1-mediated currents are diminished, and GLR-1 desensitization and pharmacology are modified. Remarkably, a secreted variant of SOL-1 delivered in trans can rescue sol-1 mutants and this rescue depends on in cis expression of SOL-2. Finally, we demonstrate that SOL-1 and SOL-2 have an ongoing role in the adult nervous system to control AMPAR-mediated currents. PMID:22958824

The SOL-2/Neto auxiliary protein modulates the function of AMPA-subtype ionotropic glutamate receptors.

PubMed

Wang, Rui; Mellem, Jerry E; Jensen, Michael; Brockie, Penelope J; Walker, Craig S; Hoerndli, Frédéric J; Hauth, Linda; Madsen, David M; Maricq, Andres V

2012-09-06

The neurotransmitter glutamate mediates excitatory synaptic transmission by gating ionotropic glutamate receptors (iGluRs). AMPA receptors (AMPARs), a subtype of iGluR, are strongly implicated in synaptic plasticity, learning, and memory. We previously discovered two classes of AMPAR auxiliary proteins in C. elegans that modify receptor kinetics and thus change synaptic transmission. Here, we have identified another auxiliary protein, SOL-2, a CUB-domain protein that associates with both the related auxiliary subunit SOL-1 and with the GLR-1 AMPAR. In sol-2 mutants, behaviors dependent on glutamatergic transmission are disrupted, GLR-1-mediated currents are diminished, and GLR-1 desensitization and pharmacology are modified. Remarkably, a secreted variant of SOL-1 delivered in trans can rescue sol-1 mutants, and this rescue depends on in cis expression of SOL-2. Finally, we demonstrate that SOL-1 and SOL-2 have an ongoing role in the adult nervous system to control AMPAR-mediated currents. Copyright © 2012 Elsevier Inc. All rights reserved.

Optical, electrical properties and structural characterization of ZnO:rGO based photodetector

NASA Astrophysics Data System (ADS)

Nath, Debarati; Mandal, S. K.; Deb, Debajit; Rakshit, J. K.; Dey, P.; Roy, J. N.

2018-04-01

Pure ZnO and ZnO:rGO composite films are prepared by sol-gel process and the effect of reduced graphene oxide(rGO) on structural, optical and electrical properties of the film are studied. UV-visspectrum shows that composite film exhibit similar optical absorbance property as pure ZnOfilm. Band gap of the film is changed from 3.32 to 3.21 eV by incorporation of rGO. From current-voltage curve it can be observed that photo current is increased significantly in composite film under red laser light illumination. This result suggests that conduction mechanism in composite film is dominated by rGO. Nyquist plot of both films show only one semicircle behavior in measured frequency range, which may be attributed to grain boundaries effects in the composite.

Electrical characteristics of paraelectric lead lanthanum zirconium titanate thin films for dynamic random access memory applications

NASA Astrophysics Data System (ADS)

Jones, R. E., Jr.; Maniar, P. D.; Olowolafe, J. O.; Campbell, A. C.; Mogab, C. J.

1992-02-01

Paraelectric lead lanthanum zirconium titanate (PLZT) films, 150 nm thick, were deposited using a spin-coat, sol-gel process followed by a 650 °C oxygen anneal. X-ray diffraction indicated complete conversion to the perovskite phase. Sputter-deposited platinum electrodes were employed with the PLZT films to form thin-film capacitors with the best combination of high charge storage density (26.1 μC/cm2 at 3 V and 36.4 μC/cm2 at 5 V) and leakage current density (0.2 μA/cm2 at 3 V and 0.5 μA/cm2 at 5 V ) reported to date. The electrical characteristics of these thin-film capacitors meet the requirements for a planar bit cell capacitor for 64-Mbit dynamic random access memories.

Effects of Humic Acid and Sunlight on the Generation and Aggregation State of Aqu/C60 Nanoparticles

EPA Science Inventory

Aqueous suspensions of nanoscale C60 aggregates (aqu/C60) were produced by stirring in water with Suwanee River Humic Acid (humic acid) and water from Call’s Creek, a small stream near Athens, GA. Time course experiments were conducted to determine the effects of sunlight and sol...

Peeling Back the Layers of Mars

NASA Technical Reports Server (NTRS)

2004-01-01

This is a 3-D model of the trench excavated by the Mars Exploration Rover Opportunity on the 23rd day, or sol, of its mission. An oblique view of the trench from a bit above and to the right of the rover's right wheel is shown. The model was generated from images acquired by the rover's front hazard-avoidance cameras.

In situ ZnO-PVA nanocomposite coated microfluidic chips for biosensing

NASA Astrophysics Data System (ADS)

Habouti, Salah; Kunstmann-Olsen, Casper; Hoyland, James D.; Rubahn, Horst-Günter; Es-Souni, Mohammed

2014-05-01

Microfluidic chips with integrated fluid and optical connectors have been generated via a simple PDMS master-mould technique. In situ coating using a Zinc oxide polyvinylalcohol based sol-gel method results in ultrathin nanocomposite layers on the fluid channels, which makes them strongly hydrophilic and minimizes auto contamination of the chips by injected fluorescent biomarkers.

Feasibility study of wind-generated electricity for rural applications in southwestern Ohio

NASA Astrophysics Data System (ADS)

Kohring, G. W.

The parameters associated with domestic production of wind generated electricity for direct use by small farms and rural homes in the southwestern Ohio region are discussed. The project involves direct utility interfaced electricity generation from a horizontal axis, down-wind, fixed pitch, wind powered induction generator system. Goals of the project are to determine: the ability to produce useful amounts of domestic wind generated electricity in the southwestern Ohio region; economic justification for domestic wind generated electrical production; and the potential of domestic wind generated electricity for reducing dependence on non-renewable energy resources in the southwestern Ohio region.

District heating and cooling systems for communities through power plant retrofit and distribution networks. Phase 1: identificaion and assessment. Final report

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

Not Available

1979-09-01

Appendix A, Utility Plant Characteristics, contains information describing the characteristics of seven utility plants that were considered during the final site selection process. The plants are: Valley Electric Generating Plant, downtown Milwaukee; Manitowoc Electric Generating Plant, downtown Manitowoc; Blount Street Electric Generating Plant, downtown Madison; Pulliam Electric Generating Plant, downtown Green Bay; Edgewater Electric Generating Plant, downtown Sheboygan; Rock River Electric Generating Plant, near Janesville and Beloit; and Black Hawk Electric Generating Plant, downtown Beloit. Additional appendices are: Future Loads; hvac Inventory; Load Calculations; Factors to Induce Potential Users; Turbine Retrofit/Distribution System Data; and Detailed Economic Analysis Results/Data.

Silica- and germania-based dual-ligand sol-gel organic-inorganic hybrid sorbents combining superhydrophobicity and π-π interaction. The role of inorganic substrate in sol-gel capillary microextraction.

PubMed

Seyyal, Emre; Malik, Abdul

2017-04-29

Principles of sol-gel chemistry were utilized to create silica- and germania-based dual-ligand surface-bonded sol-gel coatings providing enhanced performance in capillary microextraction (CME) through a combination of ligand superhydrophobicity and π-π interaction. These organic-inorganic hybrid coatings were prepared using sol-gel precursors with bonded perfluorododecyl (PF-C 12 ) and phenethyl (PhE) ligands. Here, the ability of the PF-C 12 ligand to provide enhanced hydrophobic interaction was advantageously combined with π-π interaction capability of the PhE moiety to attain the desired sorbent performance in CME. The effect of the inorganic sorbent component on microextraction performance of was explored by comparing microextraction characteristics of silica- and germania-based sol-gel sorbents. The germania-based dual-ligand sol-gel sorbent demonstrated superior CME performance compared to its silica-based counterpart. Thermogravimetric analysis (TGA) of the created silica- and germania-based dual-ligand sol-gel sorbents suggested higher carbon loading on the germania-based sorbent. This might be indicative of more effective condensation of the organic ligand-bearing sol-gel-active chemical species to the germania-based sol-gel network (than to its silica-based counterpart) evolving in the sol solution. The type and concentration of the organic ligands were varied in the sol-gel sorbents to fine-tune extraction selectivity toward different classes of analytes. Specific extraction (SE) values were used for an objective comparison of the prepared sol-gel CME sorbents. The sorbents with higher content of PF-C 12 showed remarkable affinity for aliphatic hydrocarbons. Compared to their single-ligand sol-gel counterparts, the dual-ligand sol-gel coatings demonstrated significantly superior CME performance in the extraction of alkylbenzenes, providing up to ∼65.0% higher SE values. The prepared sol-gel CME coatings provided low ng L -1 limit of detections (LOD) (4.2-26.3 ng L -1 ) for environmentally important analytes including polycyclic aromatic hydrocarbons, ketones and aliphatic hydrocarbons. In CME-GC experiments (n = 5), the capillary-to-capillary RSD value was ∼2.1%; such a low RSD value is indicative of excellent reproducibility of the sol-gel method used for the preparation of these CME coatings. The dual-ligand sol-gel coating provided stable performance in capillary microextraction of analytes from saline samples. Copyright © 2017 Elsevier B.V. All rights reserved.

Preliminary interpretation of the REMS pressure data from the first 100 sols of the MSL mission

NASA Astrophysics Data System (ADS)

Haberle, R. M.; Gómez-Elvira, J.; Torre Juárez, M.; Harri, A.-M.; Hollingsworth, J. L.; Kahanpää, H.; Kahre, M. A.; Lemmon, M.; Martín-Torres, F. J.; Mischna, M.; Moores, J. E.; Newman, C.; Rafkin, S. C. R.; Rennó, N.; Richardson, M. I.; Rodríguez-Manfredi, J. A.; Vasavada, A. R.; Zorzano-Mier, M.-P.

2014-03-01

We provide a preliminary interpretation of the Rover Environmental Monitoring Station (REMS) pressure data from the first 100 Martian solar days (sols) of the Mars Science Laboratory mission. The pressure sensor is performing well and has revealed the existence of phenomena undetected by previous missions that include possible gravity waves excited by evening downslope flows, relatively dust-free convective vortices analogous in structure to dust devils, and signatures indicative of the circulation induced by Gale Crater and its central mound. Other more familiar phenomena are also present including the thermal tides, generated by daily insolation variations, and the CO2 cycle, driven by the condensation and sublimation of CO2 in the polar regions. The amplitude of the thermal tides is several times larger than those seen by other landers primarily because Curiosity is located where eastward and westward tidal modes constructively interfere and also because the crater circulation amplifies the tides to some extent. During the first 100 sols tidal amplitudes generally decline, which we attribute to the waning influence of the Kelvin wave. Toward the end of the 100 sol period, tidal amplitudes abruptly increased in response to a nearby regional dust storm that did not expand to global scales. Tidal phases changed abruptly during the onset of this storm suggesting a change in the interaction between eastward and westward modes. When compared to Viking Lander 2 data, the REMS daily average pressures show no evidence yet for the 1-20 Pa increase expected from the possible loss of CO2 from the south polar residual cap.

Measurement of scrape-off-layer current dynamics during MHD activity and disruptions in HBT-EP

NASA Astrophysics Data System (ADS)

Levesque, J. P.; Brooks, J. W.; Abler, M. C.; Bialek, J.; Byrne, P. J.; Hansen, C. J.; Hughes, P. E.; Mauel, M. E.; Navratil, G. A.; Rhodes, D. J.

2017-08-01

We report scrape-off layer (SOL) current measurements during magnetohydrodynamic (MHD) mode activity, resonant magnetic perturbations (RMPs), and disruptions in the High Beta Tokamak—Extended Pulse (HBT-EP) device. Currents are measured via segmented plasma current Rogowski coils, jumpers running toroidally between otherwise-isolated vessel sections, and a grounded electrode in the scrape-off layer. These currents strongly depend on the plasma’s major radius, and amplitude and phase of non-axisymmetric field components. SOL currents connecting through the vessel are seen to reach  ∼0.2{--}0.5 % of the plasma current during typical kink activity and RMPs. Plasma current asymmetries and scrape-off-layer currents generated during disruptions, which are commonly called halo currents, reach  ∼4 % of I p. Asymmetric toroidal currents between vessel sections rotate at tens of kHz through most of the current quench, then symmetrize once I p reaches  ∼30 % of its pre-disruptive value. Toroidal jumper currents oscillate between co- and counter-I p, with co-I p being dominant on average during disruptions. A relative increase in local plasma current measured by a segmented I p Rogowski coil correlates with counter-I p current in the nearest toroidal jumper. Measurements are interpreted in the context of two models that produce contrary predictions for the toroidal vessel current polarity during disruptions. Plasma current asymmetry measurements are consistent with both models, and SOL currents scale with plasma displacement toward the vessel wall. The design of an upcoming SOL current diagnostic and control upgrade is also briefly presented.

77 FR 1127 - Open Meeting of the President's Council on Jobs and Competitiveness (PCJC)

Federal Register 2010, 2011, 2012, 2013, 2014

2012-01-09

... live webcast at http:[sol][sol]www.whitehouse.gov/live. DATES: The meeting will be held on January 17..., DC 20220. In general, all statements will be posted on the White House Web site (http:[sol][sol]www... 2 p.m. Eastern Time. The meeting will be broadcast on the internet via live webcast at http:[sol...

75 FR 70923 - Office of the National Coordinator for Health Information Technology; HIT Standards Committee...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-11-19

... be conducted virtually only. Dial into the meeting: 1-877-705-6006; webcast: http:[sol][sol]altarum..., and the background material will be posted on ONC's Web site after the meeting, at http:[sol][sol... committed to the orderly conduct of its advisory committee meetings. Please visit our Web site at http:[sol...

[Basic Studies on Locoregional Injection of a Newly Designed Chitin Sol].

PubMed

Chiba, Takehiro; Sugitachi, Akio; Kume, Kouhei; Segawa, Takenori; Nishinari, Yutaka; Ishida, Kaoru; Noda, Hironobu; Nishizuka, Satoshi; Kimura, Yusuke; Koeda, Keisuke; Sasaki, Akira

2015-11-01

Systemic chemotherapy in advanced cancer cases often provokes serious adverse events. We aimed to examine the fundamental properties and efficacy of a novel chitin sol, an anti-cancer agent with minor side effects designed to avoid the adverse effects of chemotherapy and enhance the QOL and ADL of patients. DAC-70 was used to create the novel agent termed DAC-70 sol. The anti-proliferative activity was assayed by the WST method using different types of cell lines. The anti-cancer efficacy of the novel agent was examined using cancer-bearing mice. DAC-70 sol was easily injectable through a 21-G needle. The sol suppressed proliferation of the cells in vitro. Intra-tumor injection of DAC-70 sol inhibited the rapid growth of solid tumors in the mice. CDDP-loaded DAC-70 sol, CDDP/DAC-70 sol, successfully controlled malignant ascites in the mice (p<0.05). Neither recurrence nor severe complications were encountered in these animals. These basic data strongly suggest that locoregional administration of our newly designed DAC-70 sol and CDDP/DAC-70 sol is clinically useful as novel cancer chemotherapy for advanced cases. This warrants further clinical studies in cancer chemotherapy.

Sol-gel route approach and improvisation in physico-chemical, structural, magnetic and electrical properties of BaCox/2Znx/2ZrxFe(12-2x)O19 ferrites

NASA Astrophysics Data System (ADS)

Kaur Jassal, Amanpreet; Mudsainiyan, R. K.; Chawla, S. K.; Anu; Bindra Narang, Sukhleen; Pubby, Kunal

2018-02-01

The structural and magnetic properties of Zn, Co and Zr cations doped barium hexaferrite [Ba(Znx/2Cox/2)xZrxFe(12-2x)O19] nanoparticles synthesized by sol-gel method have been investigated. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM) and vibrating sample magnetometer (VSM) were employed to investigate the physico-chemical properties of the obtained ferrite samples. XRD studies reveal that the magnetoplumbite structure for all sample (up to x = 0.8) have been formed and the crystallite size of nanoparticles lies in the range of 34-46 nm. At higher dopant concentration, other impurities (α-Fe2O3 and BaFe2O4 etc.) have been observed. Magnetic studies indicate that site occupancy and nature of dopant ions greatly affect the behavior of magnetic properties. The results of VSM and LCR analysis show that magnetic and electrical parameters vary with an increase in dopant concentration. The results of BET surface area of samples indicate that these types of materials could be used for catalytic properties. Dielectric constant, dielectric loss tangent and A.C. conductivity weremeasured using impedance analyzer over wide frequency range 20 Hz-120 MHz. All the three parameters increase significantly with increase in doping. Increase in dielectric constant proposes these materials for fabrication of microwave devices, while increase in dielectric loss tangent proposes these for applications such as attenuator, absorber etc.

Synthesis, characterization, temperature dependent electrical and magnetic properties of Ca3Co4O9 by a starch assisted sol-gel combustion method

NASA Astrophysics Data System (ADS)

Agilandeswari, K.; Ruban Kumar, A.

2014-09-01

In this present work we discussed the synthesis of pure Ca3Co4O9 ceramic powder by a starch assisted sol-gel combustion method. The products were characterized by powder X-ray diffraction (XRD), thermogravimetric and differential thermal analyses (TGA-DTA), Fourier transformation infrared spectroscopy (FTIR), scanning electron microscope (SEM) and UV-visible diffuse reflectance spectroscopy (DRS). X-ray diffraction pattern confirmed the formation of single phase Ca3Co4O9 at a sintering temperature of 1073 K, and it is also confirmed in the thermal analysis. SEM images indicate the presence of diffused microporous sphere like morphology and the grain sizes are in the range of 150-300 nm. Optical properties of Ca3Co4O9 ceramic show a band gap at an energy level of 2.10 eV. A maximum electrical resistivity of 0.002 mΩ cm was exhibited by Ca3Co4O9 that was decreased to 0.0012 mΩ cm, when the temperature increased from 300 K to 473 K. Dielectric studies were conducted at various temperatures from room temperature to 673 K and the results indicate that the space charge polarization contributes to the conduction mechanism. It also shows that the dielectric relaxation with activation energy is 0.96 eV. The magnetic properties as a function of temperature represent the ferri-paramagnetic phase transition at above 50 K. M-H curve shows the hysteresis loop with saturation magnetization (Ms) and confirms the presence of soft magnetic materials.

Improved reliability from a plasma-assisted metal-insulator-metal capacitor comprising a high-k HfO2 film on a flexible polyimide substrate.

PubMed

Meena, Jagan Singh; Chu, Min-Ching; Kuo, Shiao-Wei; Chang, Feng-Chih; Ko, Fu-Hsiang

2010-03-20

We have used a sol-gel spin-coating process to fabricate a new metal-insulator-metal (MIM) capacitor comprising a 10 nm-thick high-k thin dielectric HfO(2) film on a flexible polyimide (PI) substrate. The surface morphology of this HfO(2) film was investigated using atomic force microscopy and scanning electron microscopy, which confirmed that continuous and crack-free film growth had occurred on the film surface. After oxygen (O(2)) plasma pretreatment and subsequent annealing at 250 degrees C, the film on the PI substrate exhibited a low leakage current density of 3.64 x 10(-9) A cm(-2) at 5 V and a maximum capacitance density of 10.35 fF microm(-2) at 1 MHz. The as-deposited sol-gel film was completely oxidized when employing O(2) plasma at a relatively low temperature (ca. 250 degrees C), thereby enhancing the electrical performance. We employed X-ray photoelectron spectroscopy (XPS) at both high and low resolution to examine the chemical composition of the film subjected to various treatment conditions. The shift of the XPS peaks towards higher binding energy, revealed that O(2) plasma treatment was the most effective process for the complete oxidation of hafnium atoms at low temperature. A study of the insulator properties indicated the excellent bendability of our MIM capacitor; the flexible PI substrate could be bent up to 10(5) times and folded to near 360 degrees without any deterioration in its electrical performance.

Nanoscale TiO2 and Fe2O3 Architectures for Solar Energy Conversion Schemes

NASA Astrophysics Data System (ADS)

Sedach, Pavel Anatolyvich

The direct conversion of sunlight into more useable forms of energy has the potential of alleviating the environmental and social problems associated with a dependence on fossil fuels. If solar energy is to be utilized en-masse, however, it must be inexpensive and widely available. In this vein, the focus of this thesis is on nanostructured materials relevant to solar energy conversion and storage. Specifically, this thesis describes the ambient sol-gel synthesis of titanium dioxide (Ti02) nanowires designed for enhanced charge-transfer in solar collection devices, and the synthesis of novel disordered metal-oxide (MOx) catalysts for water oxidation. The introductory chapter of this thesis gives an overview of the various approaches to solar energy conversion. Sol---gel reaction conditions that enable the growth of one-dimensional (1-D) anatase TiO2 nanostructures from fluorine-doped tin oxide (FTO) for photovoltaics (PVs) are described in the second chapter. The generation of these linear nanostructures in the absence of an external bias or template is achieved by using facile experimental conditions (e.g., acetic acid (HOAc) and titanium isopropoxide (Ti(OiPr)4) in anhydrous heptane). The procedure was developed by functionalizing base-treated substrates with Ti-oxide nucleation sites that serve as a foundation for the growth of linear Ti-oxide macromolecules, which upon calcination, render uniform films of randomly oriented anatase TiO2 nanowires. A systematic evaluation of how reaction conditions (e.g., solvent volume, stoichiometry of reagents, substrate base treatment) affect the generation of these TiO 2 films is presented. A photo-organic MO. deposition route (i.e., photochemical metal-organic deposition (PMOD)) used to deposit thin-films of amorphous iron oxide (a-Fe2O3) for water oxidation catalysis is detailed in third chapter. It is shown that the irradiation of a spin-coated metal-organic film produces a film of non-crystalline a-Fe203. It is shown that annealing at various temperatures produces a-Fe 2O3 films with variable electronic properties and catalytic activities in the context of water oxidation. The study revealed that a-Fe2O3 are superior water oxidation catalysts (WOCs) relative to crystalline forms produced by high temperature annealing of the thin-films. This research has important implications in the conversion of sunlight into electricity, and then into hydrogen fuels.

Solar energy thermally powered electrical generating system

NASA Technical Reports Server (NTRS)

Owens, William R. (Inventor)

1989-01-01

A thermally powered electrical generating system for use in a space vehicle is disclosed. The rate of storage in a thermal energy storage medium is controlled by varying the rate of generation and dissipation of electrical energy in a thermally powered electrical generating system which is powered from heat stored in the thermal energy storage medium without exceeding a maximum quantity of heat. A control system (10) varies the rate at which electrical energy is generated by the electrical generating system and the rate at which electrical energy is consumed by a variable parasitic electrical load to cause storage of an amount of thermal energy in the thermal energy storage system at the end of a period of insolation which is sufficient to satisfy the scheduled demand for electrical power to be generated during the next period of eclipse. The control system is based upon Kalman filter theory.

Reactive Molecular Dynamics Investigations of Alkoxysilane Sol-Gel and Surface Coating Processes

NASA Astrophysics Data System (ADS)

Deetz, Joshua David

The ability to generate nanostructured materials with tailored morphology or chemistry is of great technological interest. One proven method of generating metal-oxide materials, and chemically modifying metal-oxide surfaces is through the reactions of molecular building blocks known as alkoxysilanes. Alkoxysilanes are a class of chemicals which contain one or more organic alkoxy groups bonded to silicon atoms. Alkoxysilane (Si-O-R) chemical groups can undergo reactions to form bridges (Si-O-M) with metal oxides. Due to their ability to "attach" to metal-oxides through condensation reactions, alkoxysilanes have a number of interesting applications, such as: the generation of synthetic siloxane materials through the sol-gel process, and the formation of functionalized surface coatings on metal-oxide surfaces. Despite widespread study of sol-gel and surface coatings processes, it is difficult to predict the morphology of the final products due to the large number of process variables involved, such as precursor molecule structure, solvent effects, solution composition, temperature, and pH. To determine the influence of these variables on the products of sol-gel and coatings processes reactive molecular dynamics simulations are used. A reactive force field was used (ReaxFF) to allow the chemical bonds in simulation to dynamically form and break. The force field parameters were optimized using a parallel optimization scheme with a combination of experimental information, and density functional theory calculations. Polycondensation of alkoxysilanes in mixtures of alcohol and water were studied. Steric effects were observed to influence the rates of hydrolysis and condensation in solutions containing different precursor monomers. By restricting the access of nucleophiles to the central silicon atom, the nucleation rate of siloxanes can be controlled. The influence of solution precursor, water, and methanol composition on reaction rates was explored. It was determined that the rate of alkoxysilane hydrolysis is strongly dependent on the concentration of water. The dynamics of siloxane cluster formation are revealed, which provides insight for experimentalists. The silanization of hydroxylated silica surfaces by alkoxysilanes was modeled in pseudo-infinite liquid solution. Butyl-, octyl-, or dodecylsilanes were exposed to hydroxylated silica surfaces in order to observe the influence of silyl headgroup size on the morphology and formation kinetics of silane films on silica substrates. The radius of gyration and order parameter of the hydrocarbon silyl groups were found to increase with grafting density. This was the first simulation study of the dynamic grafting of alkoxysilanes to a substrate.

Curiosity Rock or Soil Sampling Sites on Mars, Through November 2016

NASA Image and Video Library

2016-12-13

nal Caption Released with Image: This graphic maps locations of the sites where NASA's Curiosity Mars rover collected its first 19 rock or soil samples for analysis by laboratory instruments inside the vehicle. It also presents images of the drilled holes where 15 rock-powder samples were acquired. Curiosity scooped two soil samples at each of the other two sites: Rocknest and Gobabeb. The diameter of each drill hole is about 0.6 inch (1.6 centimeters), slightly smaller than a U.S. dime. The images used here are raw color, as recorded by the rover's Mars Hand Lens Imager (MAHLI) camera. Notice the differences in color of the material at different drilling sites. For the map, north is toward the upper left corner. The scale bar represents 2 kilometers (1.2 miles). The base map is from the High Resolution Imaging Science Experiment (HiRISE) camera on NASA's Mars Reconnaissance Orbiter. The latest sample site included is "Sebina,"where Curiosity drilled into bedrock of the Murray formation on Oct. 20, 2016, during the 1,495th Martian day, or sol, of the mission. Curiosity landed in August 2012 on the plain (named Aeolis Palus) near Mount Sharp (or Aeolis Mons). The drilling dates for the first 13 rock samples collected are, by location: "John Klein" on Feb. 8, 2013 (Sol 182); "Cumberland" on May 19, 2013 (Sol 279); "Windjana" on May 5, 2014 (Sol 621); "Confidence Hills" on Sept. 24, 2014 (Sol 759); "Mojave" on Jan. 29, 2015 (Sol 882); "Telegraph Peak" on Feb. 24, 2015 (Sol 908); "Buckskin" on July 30, 2015 (Sol 1060); "Big Sky" on Sept. 29, 2015 (Sol 1119); "Greenhorn" on Oct. 18, 2015 (Sol 1137); "Lubango" on April 23, 2016 (Sol 1320); "Okoruso" on May 5, 2016 (Sol 1332); "Oudam" on June 4, 2016 (Sol 1361); "Quela" on Sept. 18, 2016 (Sol 1464). http://photojournal.jpl.nasa.gov/catalog/PIA21254

Monolayer nanoparticle-covered liquid marbles derived from a sol-gel coating

NASA Astrophysics Data System (ADS)

Li, Xiaoguang; Wang, Yiqi; Huang, Junchao; Yang, Yao; Wang, Renxian; Geng, Xingguo; Zang, Duyang

2017-12-01

A sol-gel coating consisting of hydrophobic SiO2 nanoparticles (NPs) was used to produce monolayer NP-covered (mNPc) liquid marbles. The simplest approach was rolling a droplet on this coating, and an identifiable signet allowed determination of the coverage ratio of the resulting liquid marble. Alternatively, the particles were squeezed onto a droplet surface with two such coatings, generating surface buckling from interfacial NP jamming, and then a liquid marble was produced via a jamming-relief process in which water was added into the buckled droplet. This process revealed an ˜7% reduction in particle distance after interfacial jamming. The mNPc liquid marbles obtained by the two methods were transparent with smooth profiles, as naked droplets, and could be advantageously used in fundamental and applied researches for their unique functions.

Room temperature synthesis of agarose/sol-gel glass pieces with tailored interconnected porosity.

PubMed

Cabañas, M V; Peña, J; Román, J; Vallet-Regí, M

2006-09-01

An original shaping technique has been applied to prepare porous bodies at room temperature. Agarose, a biodegradable polysaccharide, was added as binder of a sol-gel glass in powder form, yielding an easy to mold paste. Interconnected tailored porous bodies can be straightforwardly prepared by pouring the slurry into a polymeric scaffold, previously designed by stereolitography, which is subsequently eliminated by alkaline dissolution at room temperature. The so obtained pieces behave like a hydrogel with an enhanced consistency that makes them machinable and easy to manipulate. These materials generate an apatite-like layer when immersed in a simulated body fluid, indicating a potential in vivo bioactivity. The proposed method can be applied to different powdered materials to produce pieces, at room temperature, with various shapes and sizes and with tailored interconnected porosity.

75 FR 63865 - National Science Board; Sunshine Act Meetings

Federal Register 2010, 2011, 2012, 2013, 2014

2010-10-18

... the National Science Board Web site http:[sol][sol]www.nsf.gov/nsb for additional information and schedule updates (time, place, subject matter or status of meeting) may be found at http:[sol][sol]www.nsf...

76 FR 79168 - U.S. Department of Energy Audit Guidance: For-Profit Recipients

Federal Register 2010, 2011, 2012, 2013, 2014

2011-12-21

... Federal eRulemaking Portal at http:[sol][sol]www.regulations.gov. Follow the instructions for submitting... access the guidance at: http:[sol][sol]energy.gov/management/downloads/ draft-profit-audit-guidance-fy...

Temperature-dependent impedance spectroscopy of La0.8Sr0.2FeO3 nano-crystalline material

NASA Astrophysics Data System (ADS)

Kafa, C. A.; Triyono, D.; Laysandra, H.

2017-04-01

LaFeO3 is a material with perovskite structure which electrical properties frequently investigated. Research are done due to the exhibition of excellent gas sensing behavior through resistivity comparison from the p-type semiconductor. Sr doping on LaFeO3 or La1-xSrxFeO3 are able to improve the electrical conductivity through structural modification. Using Sr dopant concentration (x) of 0.2, La0.8Sr0.2FeO3 nano-crystal pellet was synthesized. The synthesis used sol-gel method, followed by gradual heat treatment and uniaxial compaction. XRD characterization shows that the structure of the sample is Orthorhombic Perovskite. Topography of the sample by SEM reveals grain and grain boundary existence with emerging agglomeration. The electrical properties of the material, as functions of temperature and frequency, were measured by Impedance Spectroscopy method using RLC meter, for temperatures of 303-373K. Through the Nyquist plot and Bode plot, the electrical conductivity of La0.8Sr0.2FeO3 is contributed by the grain and grain boundary. Finally, the electrical permittivities of La0.8Sr0.2FeO3 are increasing with temperature increase, with the highest achieved when measured at 1 kHz frequency.

Investigation of Transport Properties of a New Biomaterials - GUM Mangosteen

NASA Astrophysics Data System (ADS)

Pradhan, Sourav S.; Sarkar, A.

2006-06-01

Biomaterial has occupied leading position in material science for various scientific and technological applications. This present work is carried out over a natural gum extracted from raw fruit of Mangosteen, an east Indian tree (Gercinia Mangostana) following extraction and purification process. Solid specimen of the said gum is developed following sol-gel like process. AC and DC electrical analysis on the dried solid specimen of the gum were carried out and showed high electrical conduction with σ ~ 1 E-03 S/cm, of which ionic and electronic contributions are 70% and 30% respectively. Analysis shows that origin of high electrical conductivity is due to presence of substantial amount of organic acid unit in its polysaccharide background. In fact the observed σ is about 1000 times of that observed in gum Arabica. Optical absorption of this new bio- materials are also studied using UV-VIS analysis. The results show its high absorption co-efficient in UV and blue part of analysed range. A complete electrical characterization of the material have been made. It has also been observed that the electronic conduction can be enhanced to 70% of the total electrical conductivity by forming complex with Iodine and organic (Citric) acid from Lemon fruit. This high potential material is being studied for development of electronic device application.

Epidemiological aspects of self-reported sleep onset latency in Japanese junior high school children.

PubMed

Alexandru, Gaina; Michikazu, Sekine; Shimako, Hamanishi; Xiaoli, Chen; Hitomi, Kanayama; Takashi, Yamagami; Robert, Williams W; Sadanobu, Kagamimori

2006-09-01

The purpose of this study was to investigate the relationships between sleep onset latency (SOL) and other sleep-wake patterns and media use habits in Japanese schoolchildren. A total of 9,718 junior high school children responded (12.8 years) and 9199 questionnaires were used in the present analyses. The questionnaire assessed sleep-wake patterns, TV viewing and videogame habits. Overall, 72.1% of the subjects reported short SOL (20 min) were strongly associated with disturbed sleep manifested especially by increased risk of night awakenings, decreased sleep depth, and bad sleep in general (overall sleep quality). Prolonged SOL was also associated with daytime sleepiness, difficulties in falling asleep, bad morning feeling and sleep insufficiency. We found a U-shaped relationship between sleep period and SOL. Increase in bedtime was accompanied by increased risk of prolonged SOL. The impact of ultra-short and ultra-long SOL (or=40 min) was also analysed. Long durations of watching television and playing videogame were significantly associated with prolonged SOL. After adjustment for sex, girls presented significantly higher risk of prolonged SOL. Body mass index adjustment did not reveal any significant results. SOL presents a significant component of sleep-wake habits; poor sleep hygiene and insufficient sleep time significantly increase SOL. Parents, healthcare practitioners and children themselves should be aware of the potentially negative influence of prolonged SOL. Additionally, the optimal coherent sleep-wake schedule must be promoted in parallel with the limitation on the viewing TV and game practices.

Curiosity First 14 Rock or Soil Sampling Sites on Mars

NASA Image and Video Library

2016-06-13

This graphic maps locations of the first 14 sites where NASA's Curiosity Mars rover collected rock or soil samples for analysis by laboratory instruments inside the vehicle. It also presents images of the drilled holes where 12 rock-powder samples were acquired. At the other two sites -- Rocknest and Gobabeb -- Curiosity scooped soil samples. The diameter of each drill hole is about 0.6 inch (1.6 centimeters), slightly smaller than a U.S. dime. The images used here are raw color, as recorded by the rover's Mars Hand Lens Imager (MAHLI) camera. Notice the differences in color of the material at different drilling sites. The latest sample site included is "Oudam," where Curiosity drilled into mudstone of the "Murray formation" on June 4, during the 1,361th Martian day, or sol, of the mission. Curiosity landed in August 2012 on the plain (named Aeolis Palus) near Mount Sharp (or Aeolis Mons). Dates when the first 11 drilled-rock samples were collected are: "John Klein" on Feb. 8, 2013 (Sol 182); "Cumberland" on May 19, 2013 (Sol 279); "Windjana" on May 5, 2014 (Sol 621); "Confidence Hills" on Sept. 24, 2014 (Sol 759); "Mojave" on Jan. 29, 2015 (Sol 882); "Telegraph Peak" on Feb. 24, 2015 (Sol 908); "Buckskin" on July 30, 2015 (Sol 1060); "Big Sky" on Sept. 29, 2015 (Sol 1119); "Greenhorn" on Oct. 18, 2015 (Sol 1137); "Lubango" on April 23, 2016 (Sol 1320); and "Okoruso" on May 5, 2016 (Sol 1332). http://photojournal.jpl.nasa.gov/catalog/PIA20748

Effect of fluticasone propionate on neutrophil chemotaxis, superoxide generation, and extracellular proteolytic activity in vitro.

PubMed Central

Llewellyn-Jones, C. G.; Hill, S. L.; Stockley, R. A.

1994-01-01

BACKGROUND--Corticosteroids are widely used in the treatment of many inflammatory conditions but the exact mode of action on neutrophil function is uncertain. Fluticasone propionate is a new topically active synthetic steroid which can be measured in body fluids and which undergoes first pass metabolism. METHODS--The effects of fluticasone propionate on the function of neutrophils isolated from normal, healthy control subjects and on the chemotactic activity of sputum sol phase were assessed. RESULTS--Preincubation of neutrophils with fluticasone propionate reduced the chemotactic response to 10(-8) mol/l F-Met-Leu-Phe (FMLP) and to a 1:5 dilution of sputum sol phase in a dose dependent manner. Furthermore, when fluticasone propionate was added to sputum from eight patients with stable chronic obstructive bronchitis the chemotactic activity of a 1:5 dilution of the sol phase fell from a mean (SE) value of 22.2 (1.21) cells/field to 19.6 (0.89), 17.1 (0.74), and 11.9 (0.6) cells field at 1 mumol/l, 10 mumol/l, and 100 mumol/l, respectively. In further experiments fluticasone propionate preincubated with neutrophils inhibited fibronectin degradation by resting cells and by cells stimulated by FMLP (15.2% inhibition of resting cells, 5.1% inhibition of stimulated cells with 1 mumol/l fluticasone propionate, 24% and 18.7% inhibition respectively at 100 mumol/l fluticasone propionate. Fluticasone propionate had no effect on generation of superoxide anion by resting or stimulated cells. CONCLUSIONS--These results indicate that fluticasone propionate has a direct suppressive effect on several aspects of neutrophil function and may suggest a role for this agent in the modulation of neutrophil mediated damage to connective tissue. PMID:8202875

Effect of fluticasone propionate on neutrophil chemotaxis, superoxide generation, and extracellular proteolytic activity in vitro.

PubMed

Llewellyn-Jones, C G; Hill, S L; Stockley, R A

1994-03-01

Corticosteroids are widely used in the treatment of many inflammatory conditions but the exact mode of action on neutrophil function is uncertain. Fluticasone propionate is a new topically active synthetic steroid which can be measured in body fluids and which undergoes first pass metabolism. The effects of fluticasone propionate on the function of neutrophils isolated from normal, healthy control subjects and on the chemotactic activity of sputum sol phase were assessed. Preincubation of neutrophils with fluticasone propionate reduced the chemotactic response to 10(-8) mol/l F-Met-Leu-Phe (FMLP) and to a 1:5 dilution of sputum sol phase in a dose dependent manner. Furthermore, when fluticasone propionate was added to sputum from eight patients with stable chronic obstructive bronchitis the chemotactic activity of a 1:5 dilution of the sol phase fell from a mean (SE) value of 22.2 (1.21) cells/field to 19.6 (0.89), 17.1 (0.74), and 11.9 (0.6) cells field at 1 mumol/l, 10 mumol/l, and 100 mumol/l, respectively. In further experiments fluticasone propionate preincubated with neutrophils inhibited fibronectin degradation by resting cells and by cells stimulated by FMLP (15.2% inhibition of resting cells, 5.1% inhibition of stimulated cells with 1 mumol/l fluticasone propionate, 24% and 18.7% inhibition respectively at 100 mumol/l fluticasone propionate. Fluticasone propionate had no effect on generation of superoxide anion by resting or stimulated cells. These results indicate that fluticasone propionate has a direct suppressive effect on several aspects of neutrophil function and may suggest a role for this agent in the modulation of neutrophil mediated damage to connective tissue.

76 FR 3180 - National Science Board; Sunshine Act Meetings; Notice

Federal Register 2010, 2011, 2012, 2013, 2014

2011-01-19

... Board Web site http:[sol][sol]www.nsf.gov/nsb for additional information and schedule updates (time, place, subject matter or status of meeting) may be found at http:[sol][sol]www.nsf.gov/nsb/notices...

Application of the docking program SOL for CSAR benchmark.

PubMed

Sulimov, Alexey V; Kutov, Danil C; Oferkin, Igor V; Katkova, Ekaterina V; Sulimov, Vladimir B

2013-08-26

This paper is devoted to results obtained by the docking program SOL and the post-processing program DISCORE at the CSAR benchmark. SOL and DISCORE programs are described. SOL is the original docking program developed on the basis of the genetic algorithm, MMFF94 force field, rigid protein, precalculated energy grid including desolvation in the frame of simplified GB model, vdW, and electrostatic interactions and taking into account the ligand internal strain energy. An important SOL feature is the single- or multi-processor performance for up to hundreds of CPUs. DISCORE improves the binding energy scoring by the local energy optimization of the ligand docked pose and a simple linear regression on the base of available experimental data. The docking program SOL has demonstrated a good ability for correct ligand positioning in the active sites of the tested proteins in most cases of CSAR exercises. SOL and DISCORE have not demonstrated very exciting results on the protein-ligand binding free energy estimation. Nevertheless, for some target proteins, SOL and DISCORE were among the first in prediction of inhibition activity. Ways to improve SOL and DISCORE are discussed.

Infrared and Raman spectra of triacetoxyvinylsilane, aqueous sol-gel and xerogel

NASA Astrophysics Data System (ADS)

Li, Ying-Sing; Ba, Abdul; Mahmood, Maleeha S.

2009-04-01

Triacetoxyvinylsilane (TAVS) has been used as a precursor to prepare sol-gel under aqueous conditions. The sol-gel product has been applied for the surface treatment of aluminum. Infrared and Raman spectra have been collected for TAVS and for TAVS sol-gel, xerogel and sol-gel-coated aluminum. Vibrational analyses have been suggested for the recorded spectra based essentially on the group frequencies and the spectral variation with the change of the sol-gel product states and the vibrational assignments of similar molecules. From the recorded infrared and Raman spectra of the sol-gel and xerogel, it is found that the sol-gel produced in the process with TAVS is essentially the same as that prepared from vinyltriethoxysilane. Thermo-gravimetric analysis (TGA) of TAVS xerogel has been conducted, and an explanation has been given in coordination with the results obtained from IR spectroscopic study of the xerogels cured at different temperatures. The study has demonstrated the thermal effect on the condensation of the sol-gel process and on the vinyl decomposition of TAVS xerogel.

Investigations on microstructure, electrical and magnetic properties of copper spinel ferrite with WO3 addition for applications in the humidity sensors

NASA Astrophysics Data System (ADS)

Tudorache, Florin

2018-04-01

In the present study we report the structural, electrical, magnetic and humidity characteristics of copper ferrite with different percent on tungsten trioxide addition. The aim of this study was to obtain more stable and sensitive active materials for humidity sensors. In order to highlight the influence of tungsten on the structural, electrical and magnetic properties, the ferrite samples were fabricated via sol-gel self-combustion method and sintered for 30 min at 1000 °C with percent between 0 and 20% tungsten trioxide additions. The X-ray diffraction investigations showed the copper ferrite phase composition. The scanning electron microscopy revealed the influence of the substitution on characteristics of the crystallites and the profilometry showed the surface topography of samples. The investigation was focused on the variation of permittivity and electrical conductivity, in relation with tungsten trioxide addition, frequency and humidity. We have also, investigated the relevant magnetic characteristics of the copper ferrite material by highlighting the influence of tungsten trioxide addition on to Curie temperature and the permeability frequency characteristics. The data suggests that the copper ferrite with tungsten trioxide addition can be used as active material for humidity sensors.

INVESTIGATION OF LEAKAGE CURRENT BEHAVIOR OF Pt/Bi0.975La0.025Fe0.975Ni0.025O3/Pt CAPACITOR MEASURED AT DIFFERENT TEMPERATURES

NASA Astrophysics Data System (ADS)

Dai, Xiu Hong; Zhao, Hong Dong; Zhang, Lei; Zhu, Hui Juan; Li, Xiao Hong; Zhao, Ya Jun; Guo, Jian Xin; Zhao, Qing Xun; Wang, Ying Long; Liu, Bao Ting; Ma, Lian Xi

2014-03-01

Polycrystalline Bi0.975La0.025Fe0.975Ni0.025O3 (BLFNO) film is fabricated on Pt/Ti/SiO2/Si(111) substrate by sol-gel method. It is found that the well-crystallized BLFNO film is polycrystalline, and the Pt/BLFNO/Pt capacitor possesses good ferroelectric properties with remnant polarization of 74 μC/cm2 at electric field of 833 kV/cm. Moreover, it is also found that the leakage current density of the Pt/BLFNO/Pt capacitor increases with the increase of measurement temperature ranging from 100 to 300 K. The leakage density of the Pt/BLFNO/Pt capacitor satisfies space-charge-limited conduction (SCLC) at higher electric field and shows little dependence on voltage polarity and temperature, but shows polarity and temperature dependence at lower applied electric field. With temperature increasing from 100 to 300 K at lower applied electric field, the most likely conduction mechanism is from Ohmic behavior to SCLC for positive biases, but no clear dominant mechanism for negative biases is shown.

Manipulating the magnetism and resistance state of Mn:ZnO/Pb(Zr0.52Ti0.48)O3 heterostructured films through electric fields

NASA Astrophysics Data System (ADS)

Li, Yong-Chao; Wu, Jun; Pan, Hai-Yang; Wang, Jue; Wang, Guang-Hou; Liu, Jun-Ming; Wan, Jian-Guo

2018-05-01

Mn:ZnO/Pb(Zr0.52Ti0.48)O3 (PZT) heterostructured films have been prepared on Pt/Ti/SiO2/Si wafers by a sol-gel process. Nonvolatile and reversible manipulation of the magnetism and resistance by electric fields has been realized. Compared with the saturation magnetic moment (Ms) in the +3.0 V case, the modulation gain of Ms can reach 270% in the -3.0 V case at room temperature. The resistance change is attributed to the interfacial potential barrier height variation and the formation of an accumulation (or depletion) layer at the Mn:ZnO/PZT interface, which can be regulated by the ferroelectric polarization direction. The magnetism of Mn:ZnO originates from bound magnetic polarons. The mobile carrier variation in Mn:ZnO, owing to interfacial polarization coupling and the ferroelectric field effect, enables the electric manipulation of the magnetism in the Mn:ZnO/PZT heterostructured films. This work presents an effective method for modulating the magnetism of magnetic semiconductors and provides a promising avenue for multifunctional devices with both electric and magnetic functionalities.

Electrical properties of tin-doped zinc oxide nanostructures doped at different dopant concentrations

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

Nasir, M. F., E-mail: babaibaik2002@yahoo.com; Zainol, M. N., E-mail: nizarzainol@yahoo.com; Hannas, M., E-mail: mhannas@gmail.com

This project has been focused on the electrical and optical properties respectively on the effect of Tin doped zinc oxide (ZnO) thin films at different dopant concentrations. These thin films were doped with different Sn dopant concentrations at 1 at%, 2 at%, 3 at%, 4 at% and 5 at% was selected as the parameter to optimize the thin films quality while the annealing temperature is fixed 500 °C. Sn doped ZnO solutions were deposited onto the glass substrates using sol-gel spin coating method. This project was involved with three phases, which are thin films preparation, deposition and characterization. The thinmore » films were characterized using Current Voltage (I-V) measurement and ultraviolet-visible-near-infrared (UV-vis-NIR) spectrophotometer (Perkin Elmer Lambda 750) for electrical properties and optical properties. The electrical properties show that the resistivity is the lowest at 4 at% Sn doping concentration with the value 3.08 × 10{sup 3} Ωcm{sup −1}. The absorption coefficient spectrum obtained shows all films exhibit very low absorption in the visible (400-800 nm) and near infrared (NIR) (>800 nm) range but exhibit high absorption in the UV range.« less

Multiferroic properties of microwave sintered PbFe12-xO19-δ

NASA Astrophysics Data System (ADS)

Prathap, S.; Madhuri, W.

2017-05-01

The effect of iron deficiency on the structural, electrical, ferroelectric and magnetic properties of nano PbFe12-xO19-δ (where x=0.0, 0.25, 0.50, 0.75, 1.0) hexaferrites prepared by sol-gel auto combustion and processed by microwaves are investigated. X-ray analysis confirms single phase magneto-plumbite phase formation. The surface morphology is studied from Field Emission Scanning Electron Microscope. Further, optical properties are investigated using Fourier Transform Infrared spectra and UV-visible spectra. AC electrical conductivity is estimated as a function of temperature and frequency in the range of room temperature (RT) to 500 °C and 100 Hz to 5MHz. AC electrical conduction analysis shows that conduction is mainly due to small polaron hopping mechanism. The variation of polarization with applied electric field exhibits hysteresis loop confirming the ferroelectric nature. The initial permeability studies with varying temperature reveals that the Curie transition temperature for the present series is around 400 °C. Variation of initial permeability with frequency ranging from 100 to 5 MHz shows a constant value (except for x=0.0) opening avenues for high frequency applications.

Rheological properties and formation mechanism of DC electric fields induced konjac glucomannan-tungsten gels.

PubMed

Wang, Lixia; Jiang, Yaoping; Lin, Youhui; Pang, Jie; Liu, Xiang Yang

2016-05-20

Konjac glucomannan-tungsten (KGM-T) hydrogel of electrochemical reversibility was successfully produced under DC electric fields in the presence of sodium tungstate. The structure and the effects of sodium tungstate concentration, KGM concentration, voltage and electric processing time on the rheological properties of the gels were investigated. pH experiments showed that KGM sol containing Na2WO4·2H2O in the vicinity of the positive electrode became acidic and the negative electrode basic after the application of DC electric fields. Under acid conditions, WO4(2-) ions transformed into isopoly-tungstic acid ions. FTIR and Raman studies indicated that isopoly-tungstic acid ions absorbed on KGM molecular chain and cross-linked with -OH groups at C-6 position on sugar units of KGM. Frequency sweep data showed with increasing sodium tungstate concentration, voltage, and electric processing time, the viscoelastic moduli, i.e., the storage and the loss moduli of the gel increased, whereas an increase in KGM concentration led to a decrease in gel viscoelastic moduli. The temperature sweep measurements indicated the obtained gel exhibited high thermal stability. Finally, the mechanism of gel formation was proposed. Our work may pave the way to use DC electric fields for the design and development of KGM gels as well as polysaccharide gels. Copyright © 2016 Elsevier Ltd. All rights reserved.

Sol-gel processing to form doped sol-gel monoliths inside hollow core optical fiber and sol-gel core fiber devices made thereby

NASA Technical Reports Server (NTRS)

Shaw, Harry C. (Inventor); Ott, Melanie N. (Inventor); Manuel, Michele V. (Inventor)

2002-01-01

A process of fabricating a fiber device includes providing a hollow core fiber, and forming a sol-gel material inside the hollow core fiber. The hollow core fiber is preferably an optical fiber, and the sol-gel material is doped with a dopant. Devices made in this manner includes a wide variety of sensors.

Sol-gel layers for ceramic microsystems application

NASA Astrophysics Data System (ADS)

Czok, Mateusz; Golonka, Leszek

2016-11-01

This paper describes research on sol-gel solutions preparation process. Utilize of a sol-gel layers in the LTCC technology for reduction of surface roughness and influence on the ceramics properties is examined and described. The influence of sol-gel layer on possible sedimentation of dyes or biological substances in channels, mixers or chambers of ceramic microfluidic structures was investigated. Moreover, properties of sol-gel coated surfaces have been precisely examined and described. Finally, positive results of conducted experiments made it possible to design and manufacture a simple microfluidic ceramic structure, with embedded protective layer of sol-gel, for fluorescence measurements.

Fabrication of piezoelectric ceramic fibers by extrusion of PZT powder and PZT sol mixture

NASA Astrophysics Data System (ADS)

Kobayashi, Yoshimasa; Um, Tae Y.; Qiu, Jinhao; Tani, Junji; Takahashi, Hirofumi

2001-07-01

This study aims to fabricate Pb(Zr,Ti)O3 (PZT) piezoelectric ceramic fibers by extrusion with mixture of PZT powder and PZT sol. The added PZT sol in this study played a role as a binder; the sol changed into PZT crystalline during sintering, and removal process of additives before sintering was not required. To obtain PZT fibers, the condition of sol viscosity adjustment, the mixture ratio of powder and sol for fiber extrusion, and the sintering condition for obtaining polycrystalline fibers were investigated. PZT precursor solution was synthesized from lead acetate trihydrate, zirconium n-propoxide and titanium isopropoxide by reflux at 120 degree(s)C for 3 hours with 2-methoxyethanol. The appropriate adjustment of spinnable sol was achieved by the addition of acetic acid for suppressing the hydrolysis reaction and the curing sol at 80 degree(s)C for promoting the condensation of sol. Green fibers with diameter of about 300micrometers were successfully extruded from the mixture of PZT powder and sol. The extruded fibers sintered at 1200 degree(s)C had the microstructure with 2-6micrometers grains and had no pores or cracks. From the result of displacement behavior measurement, PZT fibers fabricated by firing at 1200 degree(s)C in this study were considered to have desired piezoelectric properties.

Sol gel-derived hydroxyapatite films over porous calcium polyphosphate substrates for improved tissue engineering of osteochondral-like constructs.

PubMed

Lee, Whitaik David; Gawri, Rahul; Pilliar, Robert M; Stanford, William L; Kandel, Rita A

2017-10-15

Integration of in vitro-formed cartilage on a suitable substrate to form tissue-engineered implants for osteochondral defect repair is a considerable challenge. In healthy cartilage, a zone of calcified cartilage (ZCC) acts as an intermediary for mechanical force transfer from soft to hard tissue, as well as an effective interlocking structure to better resist interfacial shear forces. We have developed biphasic constructs that consist of scaffold-free cartilage tissue grown in vitro on, and interdigitated with, porous calcium polyphosphate (CPP) substrates. However, as CPP degrades, it releases inorganic polyphosphates (polyP) that can inhibit local mineralization, thereby preventing the formation of a ZCC at the interface. Thus, we hypothesize that coating CPP substrate with a layer of hydroxyapatite (HA) might prevent or limit this polyP release. To investigate this we tested both inorganic or organic sol-gel processing methods, asa barrier coating on CPP substrate to inhibit polyP release. Both types of coating supported the formation of ZCC in direct contact with the substrate, however the ZCC appeared more continuous in the tissue formed on the organic HA sol gel coated CPP. Tissues formed on coated substrates accumulated comparable quantities of extracellular matrix and mineral, but tissues formed on organic sol-gel (OSG)-coated substrates accumulated less polyP than tissues formed on inorganic sol-gel (ISG)-coated substrates. Constructs formed with OSG-coated CPP substrates had greater interfacial shear strength than those formed with ISG-coated and non-coated substrates. These results suggest that the OSG coating method can modify the location and distribution of ZCC and can be used to improve the mechanical integrity of tissue-engineered constructs formed on porous CPP substrates. Articular cartilage interfaces with bone through a zone of calcified cartilage. This study describes a method to generate an "osteochondral-like" implant that mimics this organization using isolated deep zone cartilage cells and a sol-gel hydroxyapatite coated bone substitute material composed of calcium polyphosphate (CPP). Developing a layer of calcified cartilage at the interface should contribute to enhancing the success of this "osteochondral-like" construct following implantation to repair cartilage defects. Copyright © 2017 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Fabrication of piezoelectric ceramic fibers by extrusion of Pb(Zr, Ti)O3 powder and Pb(Zr, Ti)O3 sol mixture

NASA Astrophysics Data System (ADS)

Qiu, Jinhao; Tani, Junji; Kobayashi, Yoshimasa; Um, Tae Young; Takahashi, Hirofumi

2003-06-01

In this study, Pb(Zr, Ti)O3 (PZT) piezoelectric ceramic fibers were fabricated by extrusion from a mixture of PZT powder and PZT sol. The added PZT sol in this study played the role of a binder; the sol changed into crystalline PZT during sintering, and removal of additives before sintering was not required. To obtain the required PZT fibers, the sol viscosity adjustment condition, the mixture ratio of powder and sol for fiber extrusion, and the sintering condition for obtaining polycrystalline fibers were investigated. The PZT precursor solution was synthesized from lead acetate trihydrate, zirconium n-propoxide, and titanium isopropoxide by reflux at 120 °C for 3 h with 2-methoxyethanol. The appropriate adjustment of the spinnable sol was achieved by the addition of acetic acid to suppress the hydrolysis reaction and by curing the sol at 80 °C to promote the condensation of the sol. Green fibers with diameters of about 300µm were successfully extruded from the mixture of PZT powder and sol (powder:sol = 5- 8:1, molar ratio). The extruded fibers, sintered at 1200 °C, had a microstructure with 2- 6µm grains and had no pores or cracks. From the results of displacement behavior measurements, the PZT fibers fabricated by firing at 1200 °C in this study were considered to have the desired piezoelectric properties.

Sol-gel based oxidation catalyst and coating system using same

NASA Technical Reports Server (NTRS)

Leighty, Bradley D. (Inventor); Watkins, Anthony N. (Inventor); Patry, JoAnne L. (Inventor); Schryer, Jacqueline L. (Inventor); Oglesby, Donald M. (Inventor)

2010-01-01

An oxidation catalyst system is formed by particles of an oxidation catalyst dispersed in a porous sol-gel binder. The oxidation catalyst system can be applied by brush or spray painting while the sol-gel binder is in its sol state.

ZnO-based regenerable sulfur sorbents for fluid-bed/transport reactor applications

DOEpatents

Slimane, Rachid B.; Abbasian, Javad; Williams, Brett E.

2004-09-21

A method for producing regenerable sulfur sorbents in which a support material precursor is mixed with isopropanol and a first portion of deionized water at an elevated temperature to form a sol mixture. A metal oxide precursor comprising a metal suitable for use as a sulfur sorbent is dissolved in a second portion of deionized water, forming a metal salt solution. The metal salt solution and the sol mixture are mixed with a sol peptizing agent while heating and stirring, resulting in formation of a peptized sol mixture. The metal oxide precursor is dispersed substantially throughout the peptized sol mixture, which is then dried, forming a dry peptized sol mixture. The dry peptized sol mixture is then calcined and the resulting calcined material is then converted to particles.

Displacement efficiency of alternative energy and trans-provincial imported electricity in China.

PubMed

Hu, Yuanan; Cheng, Hefa

2017-02-17

China has invested heavily on alternative energy, but the effectiveness of such energy sources at substituting the dominant coal-fired generation remains unknown. Here we analyse the displacement of fossil-fuel-generated electricity by alternative energy, primarily hydropower, and by trans-provincial imported electricity in China between 1995 and 2014 using two-way fixed-effects panel regression models. Nationwide, each unit of alternative energy displaces nearly one-quarter of a unit of fossil-fuel-generated electricity, while each unit of imported electricity (regardless of the generation source) displaces ∼0.3 unit of fossil-fuel electricity generated locally. Results from the six regional grids indicate that significant displacement of fossil-fuel-generated electricity occurs once the share of alternative energy in the electricity supply mix exceeds ∼10%, which is accompanied by 10-50% rebound in the consumption of fossil-fuel-generated electricity. These findings indicate the need for a policy that integrates carbon taxation, alternative energy and energy efficiency to facilitate China's transition towards a low-carbon economy.

Displacement efficiency of alternative energy and trans-provincial imported electricity in China

NASA Astrophysics Data System (ADS)

Hu, Yuanan; Cheng, Hefa

2017-02-01

China has invested heavily on alternative energy, but the effectiveness of such energy sources at substituting the dominant coal-fired generation remains unknown. Here we analyse the displacement of fossil-fuel-generated electricity by alternative energy, primarily hydropower, and by trans-provincial imported electricity in China between 1995 and 2014 using two-way fixed-effects panel regression models. Nationwide, each unit of alternative energy displaces nearly one-quarter of a unit of fossil-fuel-generated electricity, while each unit of imported electricity (regardless of the generation source) displaces ~0.3 unit of fossil-fuel electricity generated locally. Results from the six regional grids indicate that significant displacement of fossil-fuel-generated electricity occurs once the share of alternative energy in the electricity supply mix exceeds ~10%, which is accompanied by 10-50% rebound in the consumption of fossil-fuel-generated electricity. These findings indicate the need for a policy that integrates carbon taxation, alternative energy and energy efficiency to facilitate China's transition towards a low-carbon economy.

(YIP-10) Enabling Dynamic Oxidation Mechanisms in Reverse Infiltrated Ultra-High Temperature Ceramic Coated C-C Composites for Application in Hypersonics

DTIC Science & Technology

2013-08-09

of Hf,Zr oxychloride hydrates, triethyl borate , and phenolic resin to form precipitate free sols that turn into stable gels with no catalyst addition...minutes, shows the glass -ceramic coating (that formed a shell upon cooling) was generated from within the UHTC filled C-C composite. Notice, in Figure...generation of the coating during high temperature exposure to oxygen. The formation of a ZrO2-SiO2 glass -ceramic coating on the C-C composite is believed to

Solvent-resistant sol-gel polydimethyldiphenylsiloxane coating for on-line hyphenation of capillary microextraction with high-performance liquid chromatography.

PubMed

Segro, Scott S; Malik, Abdul

2008-09-26

A sol-gel polydimethyldiphenylsiloxane (PDMDPS) coating was developed for capillary microextraction on-line hyphenated with high-performance liquid chromatography (HPLC). This coating was created using methyltrimethoxysilane (MTMS) as the sol-gel precursor and di-hydroxy-terminated PDMDPS as the sol-gel active polymer. The methyl and phenyl groups on the sol-gel active polymer and the methyl groups on the sol-gel precursor ultimately turned into pendant groups providing the ability to extract non-polar analytes. A 40-cm segment of 0.25 mm I.D. fused silica capillary containing the sol-gel PDMDPS coating was installed as an external sampling loop in an HPLC injection port. Aqueous samples containing polycyclic aromatic hydrocarbons (PAHs), aromatic compounds, ketones, and aldehydes were passed through this capillary wherein the analytes were extracted by the sol-gel coating. The extracted analytes were then transferred to the HPLC column using isocratic or gradient elution with an acetonitrile/water mobile phase. This capillary demonstrated excellent extraction capability for non-polar (e.g., polycyclic aromatic hydrocarbons and aromatic compounds) as well as moderately polar compounds, such as aromatic amines, ketones, and aldehydes. The test results indicate that PDMDPS can be successfully immobilized into a sol-gel network and that the resulting solvent-resistant sol-gel organic-inorganic hybrid coating can be effectively used for on-line hyphenation of capillary microextraction with high-performance liquid chromatography. The test results also indicate that the sol-gel PDMDPS coated capillary is resistant to high-temperature solvents, making it suitable for applications in high-temperature HPLC. To the best of our knowledge, this is the first report on the creation of a silica-based sol-gel PDMDPS coating used in capillary microextraction on-line hyphenated to HPLC.

40 CFR 98.40 - Definition of the source category.

Code of Federal Regulations, 2012 CFR

2012-07-01

... (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING Electricity Generation § 98.40 Definition of the source category. (a) The electricity generation source category comprises electricity generating units that are subject to the requirements of the Acid Rain Program and any other electricity generating units that are...

40 CFR 98.40 - Definition of the source category.

Code of Federal Regulations, 2013 CFR

2013-07-01

... (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING Electricity Generation § 98.40 Definition of the source category. (a) The electricity generation source category comprises electricity generating units that are subject to the requirements of the Acid Rain Program and any other electricity generating units that are...

40 CFR 98.40 - Definition of the source category.

Code of Federal Regulations, 2010 CFR

2010-07-01

... (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING Electricity Generation § 98.40 Definition of the source category. (a) The electricity generation source category comprises electricity generating units that are subject to the requirements of the Acid Rain Program and any other electricity generating units that are...

40 CFR 98.40 - Definition of the source category.

Code of Federal Regulations, 2011 CFR

2011-07-01

... (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING Electricity Generation § 98.40 Definition of the source category. (a) The electricity generation source category comprises electricity generating units that are subject to the requirements of the Acid Rain Program and any other electricity generating units that are...

40 CFR 98.40 - Definition of the source category.

Code of Federal Regulations, 2014 CFR

2014-07-01

... (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING Electricity Generation § 98.40 Definition of the source category. (a) The electricity generation source category comprises electricity generating units that are subject to the requirements of the Acid Rain Program and any other electricity generating units that are...

Is It Better to Burn or Bury Waste for Clean Electricity Generation?

EPA Science Inventory

The generation of electricity through renewables has increased 5% since 2002. Although considerably less prominent than solar and wind, the use of municipal solid waste (MSW) to generate electricity represents roughly 14 percent of U.S. non-hydro renewable electricity generation....

On the development of an intrinsic hybrid composite

NASA Astrophysics Data System (ADS)

Kießling, R.; Ihlemann, J.; Riemer, M.; Drossel, W.-G.; Scharf, I.; Lampke, T.; Sharafiev, S.; Pouya, M.; F-X Wagner, M.

2016-03-01

Hybrid parts, which combine low weight with high strength, are moving into the focus of the automotive industry, due to their high potential for usage in the field of crash-relevant structures. In this contribution, the development of an intrinsic hybrid composite is presented, with a focus on the manufacturing process, complex simulations of the material behaviour and material testing. The hybrid composite is made up of a continuous fibre- reinforced plastic (FRP), in which a metallic insert is integrated. The mechanical behaviour of the individual components is characterised. For material modelling, an approach is pointed out that enables modelling at large strains by directly connected rheological elements. The connection between the FRP and the metallic insert is realised by a combination of form fit and adhesive bonds. On the one hand, adhesive bonds are generated within a sol gel process. On the other hand, local form elements of the metallic insert are pressed into the FRP. We show how these form elements are generated during the macroscopic forming process. In addition, the applied sol gel process is explained. Finally, we consider design concepts for a specimen type for high strain testing of the resulting interfaces.

Sol-gel approach to in situ creation of high pH-resistant surface-bonded organic-inorganic hybrid zirconia coating for capillary microextraction (in-tube SPME).

PubMed

Alhooshani, Khalid; Kim, Tae-Young; Kabir, Abuzar; Malik, Abdul

2005-01-07

A novel zirconia-based hybrid organic-inorganic sol-gel coating was developed for capillary microextraction (CME) (in-tube SPME). High degree of chemical inertness inherent in zirconia makes it very difficult to covalently bind a suitable organic ligand to its surface. In the present work, this problem was addressed from a sol-gel chemistry point of view. Principles of sol-gel chemistry were employed to chemically bind a hydroxy-terminated silicone polymer (polydimethyldiphenylsiloxane, PDMDPS) to a sol-gel zirconia network in the course of its evolution from a highly reactive alkoxide precursor undergoing controlled hydrolytic polycondensation reactions. A fused silica capillary was filled with a properly designed sol solution to allow for the sol-gel reactions to take place within the capillary for a predetermined period of time (typically 15-30 min). In the course of this process, a layer of the evolving hybrid organic-inorganic sol-gel polymer got chemically anchored to the silanol groups on the capillary inner walls via condensation reaction. At the end of this in-capillary residence time, the unbonded part of the sol solution was expelled from the capillary under helium pressure, leaving behind a chemically bonded sol-gel zirconia-PDMDPS coating on the inner walls. Polycyclic aromatic hydrocarbons, ketones, and aldehydes were efficiently extracted and preconcentrated from dilute aqueous samples using sol-gel zirconia-PDMDPS coated capillaries followed by thermal desorption and GC analysis of the extracted solutes. The newly developed sol-gel hybrid zirconia coatings demonstrated excellent pH stability, and retained the extraction characteristics intact even after continuous rinsing with a 0.1 M NaOH solution for 24 h. To our knowledge, this is the first report on the use of a sol-gel zirconia-based hybrid organic-inorganic coating as an extraction medium in solid phase microextraction (SPME).

Polarization induced conductive AFM on cobalt doped ZnO nanostructures

NASA Astrophysics Data System (ADS)

Sahoo, Pradosh Kumar; Mangamma, G.; Rajesh, A.; Kamruddin, M.; Dash, S.

2017-05-01

In the present work cobalt doped ZnO (CZO) nanostructures (NS) have been synthesized by of sol-gel and spin coating process. After the crystal phase confirmation by GIXRD and Raman spectroscopy, Conductive Atomic Force Microscopy (C-AFM) measurement was performed on CZO NS which shows the random distribution of electrically conducting zones on the surface of the material exhibiting current in the range 4-170 pA. We provide the possible mechanisms for variation in current distribution essential for quantitative understanding of transport properties of ZnO NS in doped and undoped forms.

High-mobility low-temperature ZnO transistors with low-voltage operation

NASA Astrophysics Data System (ADS)

Bong, Hyojin; Lee, Wi Hyoung; Lee, Dong Yun; Kim, Beom Joon; Cho, Jeong Ho; Cho, Kilwon

2010-05-01

Low voltage high mobility n-type thin film transistors (TFTs) based on sol-gel processed zinc oxide (ZnO) were fabricated using a high capacitance ion gel gate dielectric. The ion gel gated solution-processed ZnO TFTs were found to exhibit excellent electrical properties. TFT carrier mobilities were 13 cm2/V s, ON/OFF current ratios were 105, regardless of the sintering temperature used for the preparation of the ZnO thin films. Ion gel gated ZnO TFTs are successfully demonstrated on plastic substrates for the large area flexible electronics.

Low-temperature sol-gel oxide TFT with a fluoropolymer dielectric to enhance the effective mobility at low operation voltage

NASA Astrophysics Data System (ADS)

Yu, Shang-Yu; Wang, Kuan-Hsun; Zan, Hsiao-Wen; Soppera, Olivier

2017-06-01

In this article, we propose a solution-processed high-performance amorphous indium-zinc oxide (a-IZO) thin-film transistor (TFT) gated with a fluoropolymer dielectric. Compared with a conventional IZO TFT with a silicon nitride dielectric, a fluoropolymer dielectric effectively reduces the operation voltage to less than 3 V and greatly increases the effective mobility 40-fold. We suggest that the dipole layer formed at the dielectric surface facilitates electron accumulation and induces the electric double-layer effect. The dipole-induced hysteresis effect is also investigated.

Comparison of contraction times of a muscle and its motor units

NASA Technical Reports Server (NTRS)

Eldred, E.; Smith, L.; Edgerton, V. R.

1992-01-01

The twitch contraction time (CT) for each of 13 soleus (SOL) and 13 medial gastrocnemius (MG) muscles was compared with the mean CT from a sample of its motor units (MUs; 356 total) to see if the CT of a whole muscle when tested at its optimal length (Lo) differed systematically from that of its MUs tested at their individual Lo's. The CTs of the whole muscle were significantly longer in the ratio of 1.13. This is consistent with a hypothesis that electrical-field effects result in a more protracted contraction of the individual muscle fiber.

Hydrophobicity of hemp shiv treated with sol-gel coatings

NASA Astrophysics Data System (ADS)

Hussain, Atif; Calabria-Holley, Juliana; Schorr, Diane; Jiang, Yunhong; Lawrence, Mike; Blanchet, Pierre

2018-03-01

This is the first time sol-gel technology is used in the treatment of hemp shiv to develop sustainable thermal insulation building materials. The impact on the hydrophobicity of hemp shiv by depositing functionalised sol-gel coatings using hexadecyltrimethoxysilane (HDTMS) has been investigated. Bio-based materials have tendency to absorb large amounts of water due to their hydrophilic nature and highly porous structure. In this work, the influence of catalysts, solvent dilution and HDTMS loading in the silica sols on the hydrophobicity of hemp shiv surface has been reported. The hydrophobicity of sol-gel coated hemp shiv increased significantly when using acid catalysed sols which provided water contact angles of up to 118° at 1% HDTMS loading. Ethanol diluted sol-gel coatings enhanced the surface roughness of the hemp shiv by 36% as observed under 3D optical profilometer. The XPS results revealed that the surface chemical composition of the hemp shiv was altered by the sol-gel coating, blocking the hydroxyl sites responsible for hydrophilicity.

Modified silica sol coatings for surface enhancement of leather.

PubMed

Mahltig, Boris; Vossebein, Lutz; Ehrmann, Andrea; Cheval, Nicolas; Fahmi, Amir

2012-06-01

The presented study reports on differently modified silica sols for coating applications on leather. Silica sols are prepared by acidic hydrolysis of tetraethoxysilane and modified by silane compounds with fluorinated and non-fluorinated alkylgroups. In contrast to many earlier investigations regarding sol-gel applications on leather, no acrylic resin is used together with the silica sols when applying on leather. The modified silica particles are supposed to aggregate after application, forming thus a modified silica coating on the leather substrate. Scanning electron microscopy investigation shows that the applied silica coatings do not fill up or close the pores of the leather substrate. However, even if the pores of the leather are not sealed by this sol-gel coating, an improvement of the water repellent and oil repellent properties of the leather substrates are observed. These improved properties of leather by application of modified silica sols can provide the opportunity to develop sol-gel products for leather materials present in daily life.

Design of Stand-Alone Hybrid Power Generation System at Brumbun Beach Tulungagung East Java

NASA Astrophysics Data System (ADS)

Rahmat, A. N.; Hidayat, M. N.; Ronilaya, F.; Setiawan, A.

2018-04-01

Indonesian government insists to optimize the use of renewable energy resources in electricity generation. One of the efforts is launching Independent Energy Village plan. This program aims to fulfill the need of electricity for isolated or remote villages in Indonesia. In order to support the penetration of renewable energy resources in electricity generation, a hybrid power generation system is developed. The simulation in this research is based on the availability of renewable energy resources in Brumbun beach, Tulungagung, East Java. Initially, the electricity was supplied through stand-alone electricity generations which are installed at each house. Hence, the use of electricity between 5 p.m. – 9 p.m. requires high operational costs. Based on the problem above, this research is conducted to design a stand-alone hybrid electricity generation system, which may consist of diesel, wind, and photovoltaic. The design is done by using HOMER software to optimize the use of electricity from renewable resources and to reduce the operation of diesel generation. The combination of renewable energy resources in electricity generation resulted in NPC of 44.680, COE of 0,268, and CO2 emissions of 0,038 % much lower than the use of diesel generator only.

Synthesis and thermochromic property studies on W doped VO2 films fabricated by sol-gel method.

PubMed

Pan, Guoping; Yin, Jinhua; Ji, Keli; Li, Xiang; Cheng, Xingwang; Jin, Haibo; Liu, Jiping

2017-07-21

Tungsten-doped VO 2 thin films have been synthesized by a modified sol-gel process and followed by a post annealing. Vanadium pentoxide and tungstic acid as raw materials with the addition of hydrogen peroxide, concentrated hydrochloric acid (catalyst) and oxalic acid used as reducing agent were reacted in isobutanol. Finally, the uniform sol of vanadyl oxalate in isobutanol solvent was obtained as precursor. Detailed study suggested that W doped in VO 2 introduces additional electron carriers and induces the formation of V 3+ . Post annealing under vacuum promotes the releasing of chemical stress and generates oxygen vacancies in the samples. Temperature dependent transmittance study revealed that the releasing of chemical stress and deliberately introducing oxygen vacancies in W-doped VO 2 films have positive effects on enhancing its switching ability in the infrared transmittance as the metal-insulator transition (MIT) occurs. The largest switching of transmittance was obtained about 48% in the infrared range at 43 °C in 1.5%W doped VO 2 films, which is significantly larger than the reported ones. The findings in this work open a new way to synthesize the novel and thermochromic W doped VO 2 films with facility and low cost. Therefore, it has extensive application to construct smart windows and electronic devices.

Fabrication of mesoporous silica nanoparticles by sol gel method followed various hydrothermal temperature

NASA Astrophysics Data System (ADS)

Purwaningsih, Hariyati; Pratiwi, Vania Mitha; Purwana, Siti Annisa Bani; Nurdiansyah, Haniffudin; Rahmawati, Yenny; Susanti, Diah

2018-04-01

Rice husk is an agricultural waste that is potentially used as natural silica resources. Natural silica claimed to be safe in handling, cheap and can be generate from cheap resource. In this study mesoporous silica was synthesized using sodium silicate extracted from rice husk ash. This research's aim are to study the optimization of silica extraction from rice husk, characterizing mesoporous silica from sol-gel method and surfactant templating from rice husk and the effect of hydrothermal temperature on mesoporous silica nanoparticle (MSNp) formation. In this research, rice husk was extracted with sol-gel method and was followed by hydrothermal treatment; several of hydrothermal temperatures were 85°C, 100°C, 115°C, 130°C and 145° for 24 hours. X-ray diffraction analysis was identified of α-SiO2 phase and NaCl compound impurities. Scherer's analysis method for crystallite size have resulted 6.27-40.3 nm. FTIR results of silica from extraction and MSNp indicated Si-O-Si bonds on the sample. SEM result showed the morphology of the sample that has spherical shape and smooth surface. TEM result showed particle size ranged between 69,69-84,42 nm. BET showed that the pore size classified as mesoporous with pore diameter size is 19,29 nm.

Structured Ordinary Least Squares: A Sufficient Dimension Reduction approach for regressions with partitioned predictors and heterogeneous units.

PubMed

Liu, Yang; Chiaromonte, Francesca; Li, Bing

2017-06-01

In many scientific and engineering fields, advanced experimental and computing technologies are producing data that are not just high dimensional, but also internally structured. For instance, statistical units may have heterogeneous origins from distinct studies or subpopulations, and features may be naturally partitioned based on experimental platforms generating them, or on information available about their roles in a given phenomenon. In a regression analysis, exploiting this known structure in the predictor dimension reduction stage that precedes modeling can be an effective way to integrate diverse data. To pursue this, we propose a novel Sufficient Dimension Reduction (SDR) approach that we call structured Ordinary Least Squares (sOLS). This combines ideas from existing SDR literature to merge reductions performed within groups of samples and/or predictors. In particular, it leads to a version of OLS for grouped predictors that requires far less computation than recently proposed groupwise SDR procedures, and provides an informal yet effective variable selection tool in these settings. We demonstrate the performance of sOLS by simulation and present a first application to genomic data. The R package "sSDR," publicly available on CRAN, includes all procedures necessary to implement the sOLS approach. © 2016, The International Biometric Society.

Optical properties of Na2O-TiO2-SiO2 glass films prepared by the sol-gel method

NASA Astrophysics Data System (ADS)

Barton, Ivo; Matejec, Vlastimil; Mrazek, Jan; Predoana, Luminita; Zaharescu, Maria

2017-12-01

Layers based on TiO2-SiO2 systems fabricated by sol-gel method have been investigated for the preparation of planar waveguides, antireflective coatings, Bragg mirrors, etc. However, at high titania contents such materials exhibit high viscosities and tendency to phase separation. In this paper we present optical properties of films containing TiO2 which are prepared via a novel approach sol-gel on the basis of ternary Na2O-TiO2-SiO2 glasses and which can exhibit lower viscosities. Films of Na2O-TiO2-SiO2 systems were prepared from input sols mixed of silica, titania and sodium oxide sols. The silica sol was prepared from tetraethyl orthosilicate (TEOS), ethanol, hydrochloric acid and water, with a TEOS c= 2 mol/l and water/alkoxide ratio 1.75. The titania sol was mixed from titanium tetraisopropoxide (TiPr), propan-2-ol, nitric acid and water, c= 0.5 mol/l, RW= 0.42. The sodium oxide sols with c= 0.474 mol/l were prepared from sodium ethoxide and ethanol. Input sols were prepared by mixing the silica and titania sols first and then the sodium sol was added. The input sols were aged for one hour. Stable input sols were obtained. The input sols were deposited on glass and silica slides by dip-coating technique at a withdrawing speeds of 200 mm/min. Applied gel layers were thermally treated at temperatures of 450 and 900°C. Layers containing sodium oxide and titania in concentration ranges of 0-20 mol.% and 0-30 mol.% respectively have been fabricated. Optical properties of layers were determined by UV-VIS-NIR transmission and reflection spectrophotometry. Refractive indices of layers were determined by spectral ellipsometry and from transmission spectra. Optical properties were correlated with results of XRD spectroscopy, optical microscopy, and atomic force microscopy. Transparent homogenous films with a maximum refractive index of 1.61 at a wavelength of 600 nm have been obtained.

40 CFR 98.42 - GHGs to report.

Code of Federal Regulations, 2011 CFR

2011-07-01

... GREENHOUSE GAS REPORTING Electricity Generation § 98.42 GHGs to report. (a) For each electricity generating...) For each electricity generating unit that is not subject to the Acid Rain Program or otherwise... not generate electricity, you must report under subpart C of this part (General Stationary Fuel...

40 CFR 98.42 - GHGs to report.

Code of Federal Regulations, 2014 CFR

2014-07-01

... GREENHOUSE GAS REPORTING Electricity Generation § 98.42 GHGs to report. (a) For each electricity generating...) For each electricity generating unit that is not subject to the Acid Rain Program or otherwise... not generate electricity, you must report under subpart C of this part (General Stationary Fuel...

40 CFR 98.42 - GHGs to report.

Code of Federal Regulations, 2013 CFR

2013-07-01

... GREENHOUSE GAS REPORTING Electricity Generation § 98.42 GHGs to report. (a) For each electricity generating...) For each electricity generating unit that is not subject to the Acid Rain Program or otherwise... not generate electricity, you must report under subpart C of this part (General Stationary Fuel...

40 CFR 98.42 - GHGs to report.

Code of Federal Regulations, 2010 CFR

2010-07-01

... GREENHOUSE GAS REPORTING Electricity Generation § 98.42 GHGs to report. (a) For each electricity generating...) For each electricity generating unit that is not subject to the Acid Rain Program or otherwise... not generate electricity, you must report under subpart C of this part (General Stationary Fuel...

40 CFR 98.42 - GHGs to report.

Code of Federal Regulations, 2012 CFR

2012-07-01

... GREENHOUSE GAS REPORTING Electricity Generation § 98.42 GHGs to report. (a) For each electricity generating...) For each electricity generating unit that is not subject to the Acid Rain Program or otherwise... not generate electricity, you must report under subpart C of this part (General Stationary Fuel...

AORSA full wave calculations of helicon waves in DIII-D and ITER

NASA Astrophysics Data System (ADS)

Lau, C.; Jaeger, E. F.; Bertelli, N.; Berry, L. A.; Green, D. L.; Murakami, M.; Park, J. M.; Pinsker, R. I.; Prater, R.

2018-06-01

Helicon waves have been recently proposed as an off-axis current drive actuator for DIII-D, FNSF, and DEMO tokamaks. Previous ray tracing modeling using GENRAY predicts strong single pass absorption and current drive in the mid-radius region on DIII-D in high beta tokamak discharges. The full wave code AORSA, which is valid to all order of Larmor radius and can resolve arbitrary ion cyclotron harmonics, has been used to validate the ray tracing technique. If the scrape-off-layer (SOL) is ignored in the modeling, AORSA agrees with GENRAY in both the amplitude and location of driven current for DIII-D and ITER cases. These models also show that helicon current drive can possibly be an efficient current drive actuator for ITER. Previous GENRAY analysis did not include the SOL. AORSA has also been used to extend the simulations to include the SOL and to estimate possible power losses of helicon waves in the SOL. AORSA calculations show that another mode can propagate in the SOL and lead to significant (~10%–20%) SOL losses at high SOL densities. Optimizing the SOL density profile can reduce these SOL losses to a few percent.

AORSA full wave calculations of helicon waves in DIII-D and ITER

DOE PAGES

Lau, Cornwall; Jaeger, E.F.; Bertelli, Nicola; ...

2018-04-11

Helicon waves have been recently proposed as an off-axis current drive actuator for DIII-D, FNSF, and DEMO tokamaks. Previous ray tracing modeling using GENRAY predicts strong single pass absorption and current drive in the mid-radius region on DIII-D in high beta tokamak discharges. The full wave code AORSA, which is valid to all order of Larmor radius and can resolve arbitrary ion cyclotron harmonics, has been used to validate the ray tracing technique. If the scrape-off-layer (SOL) is ignored in the modeling, AORSA agrees with GENRAY in both the amplitude and location of driven current for DIII-D and ITER cases.more » These models also show that helicon current drive can possibly be an efficient current drive actuator for ITER. Previous GENRAY analysis did not include the SOL. AORSA has also been used to extend the simulations to include the SOL and to estimate possible power losses of helicon waves in the SOL. AORSA calculations show that another mode can propagate in the SOL and lead to significant (~10-20%) SOL losses at high SOL densities. Optimizing the SOL density profile can reduce these SOL losses to a few percent.« less

AORSA full wave calculations of helicon waves in DIII-D and ITER

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

Lau, Cornwall; Jaeger, E.F.; Bertelli, Nicola

Helicon waves have been recently proposed as an off-axis current drive actuator for DIII-D, FNSF, and DEMO tokamaks. Previous ray tracing modeling using GENRAY predicts strong single pass absorption and current drive in the mid-radius region on DIII-D in high beta tokamak discharges. The full wave code AORSA, which is valid to all order of Larmor radius and can resolve arbitrary ion cyclotron harmonics, has been used to validate the ray tracing technique. If the scrape-off-layer (SOL) is ignored in the modeling, AORSA agrees with GENRAY in both the amplitude and location of driven current for DIII-D and ITER cases.more » These models also show that helicon current drive can possibly be an efficient current drive actuator for ITER. Previous GENRAY analysis did not include the SOL. AORSA has also been used to extend the simulations to include the SOL and to estimate possible power losses of helicon waves in the SOL. AORSA calculations show that another mode can propagate in the SOL and lead to significant (~10-20%) SOL losses at high SOL densities. Optimizing the SOL density profile can reduce these SOL losses to a few percent.« less

Radiation hardening in sol-gel derived Er{sup 3+}-doped silica glasses

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

Hari Babu, B., E-mail: hariphy2012@gmail.com, E-mail: matthieu.lancry@u-psud.fr; León Pichel, Mónica; Institut de Chimie Moléculaire et des Matériaux d'Orsay, UMR CNRS-UPSud 8182, Université Paris Sud, 91405 Orsay

2015-09-28

The aim of the present paper is to report the effect of radiation on the Er{sup 3+}-doped sol-gel silica glasses. A possible application of these sol-gel glasses could be their use in harsh radiation environments. The sol-gel glasses are fabricated by densification of erbium salt-soaked nanoporous silica xerogels through polymeric sol-gel technique. The radiation-induced attenuation of Er{sup 3+}-doped sol-gel silica is found to increase with erbium content. Electron paramagnetic resonance studies reveal the presence of E′{sub δ} point defects. This happens in the sol-gel aluminum-silica glass after an exposure to γ-rays (kGy) and in sol-gel silica glass after an exposuremore » to electrons (MGy). The concentration levels of these point defects are much lower in γ-ray irradiated sol-gel silica glasses. When the samples are co-doped with Al, the exposure to γ-ray radiation causes a possible reduction of the erbium valence from Er{sup 3+} to Er{sup 2+} ions. This process occurs in association with the formation of aluminum oxygen hole centers and different intrinsic point defects.« less

Sol-Gel Derived Hafnia Coatings

NASA Technical Reports Server (NTRS)

Feldman, Jay D.; Stackpoole, Mairead; Blum, Yigal; Sacks, Michael; Ellerby, Don; Johnson, Sylvia M.; Venkatapathy, Ethiras (Technical Monitor)

2002-01-01

Sol-gel derived hafnia coatings are being developed to provide an oxidation protection layer on ultra-high temperature ceramics for potential use in turbine engines (ultra-efficient engine technology being developed by NASA). Coatings using hafnia sol hafnia filler particles will be discussed along with sol synthesis and characterization.

Tuning the Electrical and Thermal Conductivities of Thermoelectric Oxides through Impurity Doping

NASA Astrophysics Data System (ADS)

Torres Arango, Maria A.

Waste heat and thermal gradients available at power plants can be harvested to power wireless networks and sensors by using thermoelectric (TE) generators that directly transform temperature differentials into electrical power. Oxide materials are promising for TE applications in harsh industrial environments for waste heat recovery at high temperatures in air, because they are lightweight, cheaply produced, highly efficient, and stable at high temperatures in air. Ca3Co4O9(CCO) with layered structure is a promising p-type thermoelectric oxide with extrapolated ZT value of 0.87 in single crystal form [1]. However the ZT values for the polycrystalline ceramics remain low of ˜0.1-0.3. In this research, nanostructure engineering approaches including doping and addition of nanoinclusions were applied to the polycrystalline CCO ceramic to improve the energy conversion efficiency. Polycrystalline CCO samples with various Bi doping levels were prepared through the sol-gel chemical route synthesis of powders, pressing and sintering of the pellets. Microstructure features of Bi doped ceramic bulk samples such as porosity, development of crystal texture, grain boundary dislocations and segregation of Bi dopants at various grain boundaries are investigated from microns to atomic scale. The results of the present study show that the Bi-doping is affecting both the electrical conductivity and thermal conductivity simultaneously, and the optimum Bi doping level is strongly correlated with the microstructure and the processing conditions of the ceramic samples. At the optimum doping level and processing conditions of the ceramic samples, the Bi substitution of Ca results in the increase of the electrical conductivity, decrease of the thermal conductivity, and improvement of the crystal texture. The atomic resolution Scanning Transmission Electron Microscopy (STEM) Z-contrast imaging and the chemistry analysis also reveal the Bi-segregation at grain boundaries of CCO polycrystalline samples. In order to further decrease the thermal conductivity and increase the overall energy conversion efficiency of ceramic samples. The highest ZT value obtained is 0.32 at 973K for Ca and Co site Bi doping. The effect of the nanoinclusions on the performance and the microstructure of CCO were investigated as well.

Stationary diesel engines for use with generators to supply electric power

NASA Technical Reports Server (NTRS)

1977-01-01

The procurement of stationary diesel engines for on-site generation of electric power deals with technical criteria and policy relating to federal agency, not electrical components of diesel-generator sets or for the design of electric-power generating plants or their air-pollution or noise control equipment.

Effect of annealing temperature on optical and electrical properties of ZrO2-SnO2 based nanocomposite thin films

NASA Astrophysics Data System (ADS)

Anitha, V. S.; Lekshmy, S. Sujatha; Berlin, I. John; Joy, K.

2014-01-01

Transparent nanocomposite ZrO2-SnO2 thin films were prepared by sol-gel dip-coating technique. Films were annealed at 500°C, 800°C and 1200°C respectively. X-ray diffraction(XRD) spectra showed a mixture of three phases: tetragonal ZrO2 and SnO2 and orthorhombic ZrSnO4. The grain size of all the three phases' increased with annealing temperature. An average transmittance greater than 85%(in UV-Visible region) is observed for all the films. The band gap for the films decreased from 4.79 eV to 4.62 eV with increase in annealing temperature from 500 to 1200 °C. The electrical resistivity increased with increase in annealing temperature. Such composite ZrO2-SnO2 films can be used in many applications and in optoelectronic devices.

Electrical relaxation, optical and magnetic studies of nanocrystalline lithium ferrite synthesized by different chemical routes

NASA Astrophysics Data System (ADS)

Cheruku, Rajesh; Govindaraj, G.; Vijayan, Lakshmi

2017-12-01

The nanocrystalline lithium ferrite was synthesized by wet chemical methods such as solution combustion technique, sol-gel, and hydrothermal for a comparative study. Different characterization techniques like x-ray powder diffraction and thermal analysis were employed to confirm the structure and phase. Temperature-dependent Raman analysis was employed to classify the phonon modes associated with precise atomic motions existing in the synthesized materials. Morphology of sample surface was explored by scanning electron microscopy, and elemental analysis was done by energy dispersive spectroscopy analysis. The nanocrystalline nature of the materials was confirmed through transmission electron microscopy. Magnetic properties of these samples were explored through a vibrating sample magnetometer. Ac electrical impedance spectroscopy data were investigated using two Cole-Cole functions, and activation energies were calculated for all materials. Among them, solution combustion prepared lithium ferrite shows the highest conductivity and lowest activation energy.

Surface plasmon resonances, optical properties, and electrical conductivity thermal hystersis of silver nanofibers produced by the electrospinning technique.

PubMed

Barakat, Nasser A M; Woo, Kee-Do; Kanjwal, Muzafar A; Choi, Kyung Eun; Khil, Myung Seob; Kim, Hak Yong

2008-10-21

In the present study, silver metal nanofibers have been successfully prepared by using the electrospinning technique. Silver nanofibers have been produced by electrospinning a sol-gel consisting of poly(vinyl alcohol) and silver nitrate. The dried nanofiber mats have been calcined at 850 degrees C in an argon atmosphere. The produced nanofibers do have distinct plasmon resonance compared with the reported silver nanoparticles. Contrary to the introduced shapes of silver nanoparticles, the nanofibers have a blue-shifted plasmon resonance at 330 nm. Moreover, the optical properties study indicated that the synthesized nanofibers have two band gap energies of 0.75 and 2.34 eV. An investigation of the electrical conductivity behavior of the obtained nanofibers shows thermal hystersis. These privileged physical features greatly widen the applications of the prepared nanofibers in various fields.

Hydrogen and electricity production in a light-assisted microbial photoelectrochemical cell with CaFe2O4 photocathode

NASA Astrophysics Data System (ADS)

Chen, Qing-Yun; Zhang, Kai; Liu, Jian-Shan; Wang, Yun-Hai

2017-04-01

A microbial photoelectrochemical cell (MPEC) was designed with a p-type CaFe2O4 semiconductor as the photoelectrode for simultaneous hydrogen and electricity production under light illumination. The CaFe2O4 photoelectrode was synthesized by the sol-gel method and well characterized by x-ray diffraction, field emission scanning electron microscope, and UV-Vis-NIR spectrophotometer. The linear sweep voltammogram of the CaFe2O4 photoelectrode presented the cathodic photocurrent output. For the MPEC, with an external resistance of 2000 Ω, the maximum power density of 143 mW was obtained. Furthermore, with an external resistance of 100 Ω, the maximum hydrogen production rate of 6.7 μL·cm-2 could be achieved. The MPEC with CaFe2O4 photocathode was compared to MPEC with other photocathodes as well as photocatalytic water splitting technology.

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

Not Available

The Sol Lynn site, also known as Industrial Transformers site, is located in Houston, Texas. The area around the three-quarter-acre site is a mix of residential, commercial, and light industrial facilities. Approximately 2,000 residents and 100,000 other people move within a one-mile radius of the site on a daily basis due to recreational activities associated with the area. The site operated as an electrical transformer salvage and recycling company between 1971 and 1978, and as a chemical recycling and supply company from 1979 through 1980. The first documented investigation of this site took place during the fall of 1971 whenmore » the City of Houston Water Pollution Control Division noted that workers at Industrial Transformers poured oil out of electrical transformers onto the ground during transformer dismantling. In 1981, strong odors originating from the site were brought to the attention of the Texas Department of Water Resources, the predecessor agency of the Texas Water Commission (TWC).« less

Studies on structural and electrical properties of nanostructured RMnO3 (R = Gd & Ho)

NASA Astrophysics Data System (ADS)

Sapana, Solanki; Dhruv, Davit; Joshi, Zalak; Gadani, Keval; Rathod, K. N.; Boricha, Hetal; Shrimali, V. G.; Trivedi, R. K.; Joshi, A. D.; Pandya, D. D.; Solanki, P. S.; Shah, N. A.

2017-05-01

We report the results of the studies on the structural and electrical properties of multiferroic GdMnO3 and HoMnO3 materials synthesized by sol-gel route. Structural analysis of the results of X-ray diffraction (XRD) measurement shows that materials are found to be crystallized in orthorhombic and hexagonal symmetry, respectively for GdMnO3 and HoMnO3. Frequency dependent dielectric properties of nanostructured GdMnO3 and HoMnO3 were carried out using LCR meter in the frequency range of 100Hz to 2MHz at room temperature. Dielectric constant decreases with increasing frequency for both the nanostructured multiferroics which can be attributed to the dipole relaxation process. AC conductivity (σAC) has been measured for both the samples and fitted theoretically by using power law equation.

76 FR 55377 - Public Utility District No. 1 of Okanogan County, WA, Notice of Availability of Final...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-09-07

... Commission in the Public Reference Room or may be viewed on the Commission's Web site at http:[sol][sol]www... http:[sol][sol]www.ferc.gov/docs- filing/esubscription.asp to be notified via e-mail of new filings and...

Characterization and tailoring of porous sol-gel dielectrics for interlayer dielectric applications

NASA Astrophysics Data System (ADS)

Rogojevic, Svetlana

A new, better insulator is needed to replace SiO2 in the next generation of microelectronic devices. The dielectric constant of porous materials can be tailored by adjusting the porosity, so that their use can be extended to more than one generation of devices. Silica xerogel films with wide range of porosities (25 90%) are fabricated by varying the rate of solvent evaporation during spin-coating. Even better porosity control is achieved by using mixtures of high and low boiling point solvents, and allowing one solvent to evaporate completely during spin-coating. The quartz crystal microbalance method was employed to measure the traces of moisture adsorbed in xerogel films of varying porosities. By employing two different surface modifiers, it is demonstrated that the level of hydrophobicity is a function of surface chemistry, and can be tailored by using a suitable surface modifier. To investigate the interaction of xerogels with other materials, metallic layers were deposited on xerogel films, and subsequently annealed. When annealed in the ambient with trace amount of oxygen, Ta and Cu films undergo morphological instabilities. These morphological changes may lead to the erroneous interpretation of the Rutherford backscattering spectra as metal diffusion. When the samples are capped with a Si3N4 layer, Cu and Ta do not show diffusion through xerogel when annealed up to 650°C. Bias-temperature stressing was conducted in order to assess Cu drift through xerogel in the presence of an electric field. Contrary to what is normally observed with other dielectrics, the leakage current and C-V curve shifts were larger with an Al electrode than with a Cu electrode. This indicates that the surface modification of xerogel can contribute to the smaller charge injection from the Cu/xerogel interface, or to the inhibition of Cu diffusion, thus offering a possibility of designing future monolayer diffusion barriers for porous materials. Two possible paths of mass transfer in porous solids are identified: bulk and surface diffusion. Three driving forces are also analyzed: concentration gradient, electric field, and curvature gradient. The model of diffusion through porous solids shows the effects of the electric field, the solid network thickness, porosity, surface and bulk diffusivity. The model is a useful tool for designing and interpreting the experiments, in order to assess the role of surface diffusion in porous materials.

Short-Term Energy Outlook Model Documentation: Electricity Generation and Fuel Consumption Models

EIA Publications

2014-01-01

The electricity generation and fuel consumption models of the Short-Term Energy Outlook (STEO) model provide forecasts of electricity generation from various types of energy sources and forecasts of the quantities of fossil fuels consumed for power generation. The structure of the electricity industry and the behavior of power generators varies between different areas of the United States. In order to capture these differences, the STEO electricity supply and fuel consumption models are designed to provide forecasts for the four primary Census regions.

Composition gradient optimization and electrical characterization of (Pb, Ca)TiO3 thin films

NASA Astrophysics Data System (ADS)

Bao, Dinghua; Mizutani, Nobuyasu; Zhang, Liangying; Yao, Xi

2001-01-01

Compositionally graded (Pb, Ca)TiO3 thin films were prepared by a monoethanolamine-modified sol-gel technique on platinum-coated silicon substrates at the annealing temperature of 600 °C. The composition gradient of the films was greatly improved by a modified annealing method. The dielectric constants, for up-graded and down-graded films annealed at 600 °C for 60 min, were found to be 469 and 355, respectively. Both were larger than those reported for conventional (Pb, Ca)TiO3 thin films. The compositionally graded films had large polarization offsets in hysteresis loops when excited by an alternating electric field. The more smooth the composition gradient of the graded film, the larger the polarization offset. This was consistent with a theoretical model reported previously by Mantese and coworkers [Appl. Phys. Lett. 71, 2047 (1997)]. The magnitude of polarization offset displayed a power-law dependence on the electric field, and the direction of the offset depended on the direction of the composition gradient with respect to the substrate. Both up-graded and down-graded films had good leakage current characteristics.

Optical, electrical and ferromagnetic studies of ZnO:Fe diluted magnetic semiconductor nanoparticles for spintronic applications

NASA Astrophysics Data System (ADS)

Elilarassi, R.; Chandrasekaran, G.

2017-11-01

In the present investigation, diluted magnetic semiconductor (Zn1-xFexO) nanoparticles with different doping concentrations (x = 0, 0.02, 0.04, 0.06, and 0.08) were successfully synthesized by sol-gel auto-combustion method. The crystal structure, morphology, optical, electrical and magnetic properties of the prepared samples were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), energy dispersive analysis using x-rays (EDAX), ultraviolet-visible spectrophotometer, fluorescence spectroscope (FS), vibrating sample magnetometer (VSM) and broad band dielectric spectrometer (BDS). XRD results reveal that all the samples possess hexagonal wurtzite crystal structure with good crystalline quality. The absence of impurity phases divulge that Fe ions are well incorporated into the ZnO crystal lattice. The substitutional incorporation of Fe3+ at Zn sites is reflected in optical absorption spectra of the samples. Flouorescence spectra of the samples show a strong near-band edge related UV emission as well as defect related visible emissions. The semiconducting behavior of the samples has been confirmed through electrical conductivity measurements. Magnetic measurements indicated that all the samples possess ferromagnetism at room temperature.

Electrical conductivity and Hf 4+ ion substitution range in NaSICON system

NASA Astrophysics Data System (ADS)

Essoumhi, A.; Favotto, C.; Mansori, M.; Ouzaouit, K.; Satre, P.

2007-03-01

In this paper, we present the synthesis and characterizations of NaSICON-type ionic conducting ceramics of the general formula Na 1+ xM 1.775Si x-0.9P 3.9- xO 12 with 1.8 ≤ x ≤ 2.2 and M = Zr or Hf. The effect of the total substitution of zirconium by hafnium on electric properties has been studied. The various compositions were prepared by using the sol-gel method and the synthesized precursors were characterized by coupled DTA-TG. The oxides obtained after pyrolysis of the precursors were identified by X-ray diffraction. A sintering study by thermodilatometry permits to select the best thermal cycle adapted to our ceramics. Furthermore, the electric conductivity of the sintered ceramic samples was characterized by complex impedance spectroscopy. These results show that ceramics containing Zr synthesized by soft method, present a higher total conductivity than those obtained in literature (to be around 10 -4 S cm -1). The total substitution of Zr by Hf still improves this conductivity for some compositions.

X-ray Study of the Electric Double Layer at the n-Hexane/Nanocolloidal Silica Interface

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

Tikhonov,A.

The spatial structure of the transition region between an insulator and an electrolyte solution was studied with x-ray scattering. The electron-density profile across the n-hexane/silica sol interface (solutions with 5, 7, and 12 nm colloidal particles) agrees with the theory of the electrical double layer and shows separation of positive and negative charges. The interface consists of three layers, i.e., a compact layer of Na{sup +}, a loose monolayer of nanocolloidal particles as part of a thick diffuse layer, and a low-density layer sandwiched between them. Its structure is described by a model in which the potential gradient at themore » interface reflects the difference in the potentials of 'image forces' between the cationic Na{sup +} and anionic nanoparticles and the specific adsorption of surface charge. The density of water in the large electric field ({approx}10{sup 9}-10{sup 10} V/m) of the transition region and the layering of silica in the diffuse layer is discussed.« less

Bouncing on Mars and the Moon-the role of gravity on neuromuscular control: correlation of muscle activity and rate of force development.

PubMed

Ritzmann, Ramona; Freyler, Kathrin; Krause, Anne; Gollhofer, Albert

2016-11-01

On our astronomical neighbors Mars and the Moon, bouncing movements are the preferred locomotor techniques. During bouncing, the stretch-shortening cycle describes the muscular activation pattern. This study aimed to identify gravity-dependent changes in kinematic and neuromuscular characteristics in the stretch-shortening cycle. Hence, neuromuscular control of limb muscles as well as correlations between the muscles' pre-activation, reflex components, and force output were assessed in lunar, Martian, and Earth gravity. During parabolic flights, peak force (F max ), ground-contact-time, rate of force development (RFD), height, and impulse were measured. Electromyographic (EMG) activities in the m. soleus (SOL) and gastrocnemius medialis (GM) were assessed before (PRE) and during bounces for the reflex phases short-, medium-, and long-latency response (SLR, MLR, LLR). With gradually decreasing gravitation, F max , RFD, and impulse were reduced, whereas ground-contact time and height increased. Concomitantly, EMG_GM decreased for PRE, SLR, MLR, and LLR, and in EMG_SOL in SLR, MLR, and LLR. For SLR and MLR, F max and RFD were positively correlated to EMG_SOL. For PRE and LLR, RFD and F max were positively correlated to EMG_GM. Findings emphasize that biomechanically relevant kinematic adaptations in response to gravity variation were accompanied by muscle- and phase-specific modulations in neural control. Gravitational variation is anticipated and compensated for by gravity-adjusted muscle activities. Importantly, the pre-activation and reflex phases were differently affected: in SLR and MLR, SOL is assumed to contribute to the decline in force output with a decreasing load, and, complementary in PRE and LLR, GM seems to be of major importance for force generation. Copyright © 2016 the American Physiological Society.

Recent advances in preparation and application of hybrid organic-silica monolithic capillary columns.

PubMed

Ou, Junjie; Lin, Hui; Zhang, Zhenbin; Huang, Guang; Dong, Jing; Zou, Hanfa

2013-01-01

Hybrid organic-silica monolithic columns, regarded as a second generation of silica-based monoliths, have received much interest due to their unique properties over the pure silica-based monoliths. This review mainly focuses on development in the fields of preparation of hybrid monolithic columns in a capillary and their application for CEC and capillary liquid chromatography separation, as well as for sample pretreatment of solid-phase microextraction and immobilized enzyme reactor since July 2010. The preparation approaches are comprehensively summarized with three routes: (i) general sol-gel process using trialkoxysilanes and tetraalkoxysilanes as coprecursors; (ii) "one-pot" process of alkoxysilanes and organic monomers concomitantly proceeding sol-gel chemistry and free radical polymerization; and (iii) other polymerization approaches of organic monomers containing silanes. The modification of hybrid monoliths containing reactive groups to acquire the desired surface functionality is also described. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Sol-gel hybrid films based on organosilane and montmorillonite for corrosion inhibition of AA2024.

PubMed

Dalmoro, V; dos Santos, J H Z; Armelin, E; Alemán, C; Azambuja, D S

2014-07-15

The present work reports the production of films on AA2024-T3 composed of vinyltrimethoxysilane (VTMS)/tetraethylorthosilicate (TEOS) with incorporation of montmorillonite (sodium montmorillonite and montmorillonite modified with quaternary ammonium salt, abbreviated Na and 30B, respectively), generated by the sol-gel process. According to FT-IR analyses the incorporation of montmorillonite does not affect silica network. Electrochemical characterization was performed by electrochemical impedance spectroscopy measurement in 0.05 mol L(-1) NaCl solution. Results indicate that montmorillonite incorporation improves the corrosion protection compared to the non-modified system. Scanning electron microscopy micrographs reveal that high concentrations of montmorillonite provide agglomerations on the metallic surface, which is in detriment of the anticorrosive performance. The VTMS/TEOS/30B films with the lowest concentration (22 mg L(-1)) of embedded clay provide the highest corrosion protection. Copyright © 2014 Elsevier Inc. All rights reserved.

Ten-minute analysis of drugs and metabolites in saliva by surface-enhanced Raman spectroscopy

NASA Astrophysics Data System (ADS)

Shende, Chetan; Inscore, Frank; Maksymiuk, Paul; Farquharson, Stuart

2005-11-01

Rapid analysis of drugs in emergency room overdose patients is critical to selecting appropriate medical care. Saliva analysis has long been considered an attractive alternative to blood plasma analysis for this application. However, current clinical laboratory analysis methods involve extensive sample extraction followed by gas chromatography and mass spectrometry, and typically require as much as one hour to perform. In an effort to overcome this limitation we have been investigating metal-doped sol-gels to both separate drugs and their metabolites from saliva and generate surface-enhanced Raman spectra. We have incorporated the sol-gel in a disposable lab-on-a-chip format, and generally no more than a drop of sample is required. The detailed molecular vibrational information allows chemical identification, while the increase in Raman scattering by six orders of magnitude or more allows detection of microg/mL concentrations. Measurements of cocaine, its metabolite benzoylecgonine, and several barbiturates are presented.

Safety Arguments for Next Generation, Location Aware Computing

NASA Technical Reports Server (NTRS)

Johnson, C. W.; Holloway, C. M.

2010-01-01

Concerns over accuracy, availability, integrity, and continuity have limited the integration of Global Positioning System (GPS) and Global Navigation Satellite System (GLONASS) for safety-critical applications. More recent augmentation systems, such as the European Geostationary Navigation Overlay Service (EGNOS) and the North American Wide Area Augmentation System (WAAS) have begun to address these concerns. Augmentation architectures build on the existing GPS/GLONASS infrastructures to support location based services in Safety of Life (SoL) applications. Much of the technical development has been directed by air traffic management requirements, in anticipation of the more extensive support to be offered by GPS III and Galileo. WAAS has already been approved to provide vertical guidance for aviation applications. During the next twelve months, the full certification of EGNOS for SoL applications is expected. This paper discusses similarities and differences between the safety assessment techniques used in Europe and North America.

Electrical power generation by mechanically modulating electrical double layers.

PubMed

Moon, Jong Kyun; Jeong, Jaeki; Lee, Dongyun; Pak, Hyuk Kyu

2013-01-01

Since Michael Faraday and Joseph Henry made their great discovery of electromagnetic induction, there have been continuous developments in electrical power generation. Most people today get electricity from thermal, hydroelectric, or nuclear power generation systems, which use this electromagnetic induction phenomenon. Here we propose a new method for electrical power generation, without using electromagnetic induction, by mechanically modulating the electrical double layers at the interfacial areas of a water bridge between two conducting plates. We find that when the height of the water bridge is mechanically modulated, the electrical double layer capacitors formed on the two interfacial areas are continuously charged and discharged at different phases from each other, thus generating an AC electric current across the plates. We use a resistor-capacitor circuit model to explain the results of this experiment. This observation could be useful for constructing a micro-fluidic power generation system in the near future.

Passive flow heat exchanger simulation for power generation from solar pond using thermoelectric generators

NASA Astrophysics Data System (ADS)

Baharin, Nuraida'Aadilia; Arzami, Amir Afiq; Singh, Baljit; Remeli, Muhammad Fairuz; Tan, Lippong; Oberoi, Amandeep

2017-04-01

In this study, a thermoelectric generator heat exchanger system was designed and simulated for electricity generation from solar pond. A thermoelectric generator heat exchanger was studied by using Computational Fluid Dynamics to simulate flow and heat transfer. A thermoelectric generator heat exchanger designed for passive in-pond flow used in solar pond for electrical power generation. A simple analysis simulation was developed to obtain the amount of electricity generated at different conditions for hot temperatures of a solar pond at different flow rates. Results indicated that the system is capable of producing electricity. This study and design provides an alternative way to generate electricity from solar pond in tropical countries like Malaysia for possible renewable energy applications.

Displacement efficiency of alternative energy and trans-provincial imported electricity in China

PubMed Central

Hu, Yuanan; Cheng, Hefa

2017-01-01

China has invested heavily on alternative energy, but the effectiveness of such energy sources at substituting the dominant coal-fired generation remains unknown. Here we analyse the displacement of fossil-fuel-generated electricity by alternative energy, primarily hydropower, and by trans-provincial imported electricity in China between 1995 and 2014 using two-way fixed-effects panel regression models. Nationwide, each unit of alternative energy displaces nearly one-quarter of a unit of fossil-fuel-generated electricity, while each unit of imported electricity (regardless of the generation source) displaces ∼0.3 unit of fossil-fuel electricity generated locally. Results from the six regional grids indicate that significant displacement of fossil-fuel-generated electricity occurs once the share of alternative energy in the electricity supply mix exceeds ∼10%, which is accompanied by 10–50% rebound in the consumption of fossil-fuel-generated electricity. These findings indicate the need for a policy that integrates carbon taxation, alternative energy and energy efficiency to facilitate China's transition towards a low-carbon economy. PMID:28211467

Insights into the annealing process of sol-gel TiO2 films leading to anatase development: The interrelationship between microstructure and optical properties

NASA Astrophysics Data System (ADS)

Blanco, E.; Domínguez, M.; González-Leal, J. M.; Márquez, E.; Outón, J.; Ramírez-del-Solar, M.

2018-05-01

The microstructure and optical properties of TiO2 thin films, prepared by the sol-gel dip coating technique on glass substrates, were inspected. After deposition, the films were annealed at several temperatures in the 400-850 °C range and the resulting nanostructured films were studied by different techniques showing that their structural and optical characteristics evolved significantly with the increased annealing temperature. The analysis of these results by the assumption of the Tauc Lorenz model and the use of Wemple-DiDomenico equation leads to a correlation between microstructural aspects and optical characteristics of the films. Thus, crystallization processes (nucleation, growth and phase transformation) and the evolution of films texture and thickness with increasing annealing temperatures are related with the variation of the refractive index, average gap and extinction coefficient during annealing. Finally, the free-carrier concentration in the films, estimated from the Spitzer-Fan model, ranged from 1.44 × 1019 cm-3 to 3.07 × 1019 cm-3 with the changing annealing temperature, which is in agreement with those obtained in similar anatase thin films from electrical measurement techniques.

Induced conductivity in sol-gel ZnO films by passivation or elimination of Zn vacancies

NASA Astrophysics Data System (ADS)

Winarski, D. J.; Anwand, W.; Wagner, A.; Saadatkia, P.; Selim, F. A.; Allen, M.; Wenner, B.; Leedy, K.; Allen, J.; Tetlak, S.; Look, D. C.

2016-09-01

Undoped and Ga- and Al- doped ZnO films were synthesized using sol-gel and spin coating methods and characterized by X-ray diffraction, high-resolution scanning electron microscopy (SEM), optical spectroscopy and Hall-effect measurements. SEM measurements reveal an average grain size of 20 nm and distinct individual layer structure. Measurable conductivity was not detected in the unprocessed films; however, annealing in hydrogen or zinc environment induced significant conductivity (˜10-2 Ω .cm) in most films. Positron annihilation spectroscopy measurements provided strong evidence that the significant enhancement in conductivity was due to hydrogen passivation of Zn vacancy related defects or elimination of Zn vacancies by Zn interstitials which suppress their role as deep acceptors. Hydrogen passivation of cation vacancies is shown to play an important role in tuning the electrical conductivity of ZnO, similar to its role in passivation of defects at the Si/SiO2 interface that has been essential for the successful development of complementary metal-oxide-semiconductor (CMOS) devices. By comparison with hydrogen effect on other oxides, we suggest that hydrogen may play a universal role in oxides passivating cation vacancies and modifying their electronic properties.

Chronic hypobaric hypoxia increases isolated rat fast-twitch and slow-twitch limb muscle force and fatigue.

PubMed

El-Khoury, R; Bradford, A; O'Halloran, K D

2012-01-01

Chronic hypoxia alters respiratory muscle force and fatigue, effects that could be attributed to hypoxia and/or increased activation due to hyperventilation. We hypothesized that chronic hypoxia is associated with phenotypic change in non-respiratory muscles and therefore we tested the hypothesis that chronic hypobaric hypoxia increases limb muscle force and fatigue. Adult male Wistar rats were exposed to normoxia or hypobaric hypoxia (PB=450 mm Hg) for 6 weeks. At the end of the treatment period, soleus (SOL) and extensor digitorum longus (EDL) muscles were removed under pentobarbitone anaesthesia and strips were mounted for isometric force determination in Krebs solution in standard water-jacketed organ baths at 25 °C. Isometric twitch and tetanic force, contractile kinetics, force-frequency relationship and fatigue characteristics were determined in response to electrical field stimulation. Chronic hypoxia increased specific force in SOL and EDL compared to age-matched normoxic controls. Furthermore, chronic hypoxia decreased endurance in both limb muscles. We conclude that hypoxia elicits functional plasticity in limb muscles perhaps due to oxidative stress. Our results may have implications for respiratory disorders that are characterized by prolonged hypoxia such as chronic obstructive pulmonary disease (COPD).

Iron-based soft magnetic composites with Mn-Zn ferrite nanoparticles coating obtained by sol-gel method

NASA Astrophysics Data System (ADS)

Wu, Shen; Sun, Aizhi; Xu, Wenhuan; Zhang, Qian; Zhai, Fuqiang; Logan, Philip; Volinsky, Alex A.

2012-11-01

This paper focuses on iron-based soft magnetic composites which were synthesized by utilizing Mn-Zn ferrite nanoparticles to coat iron powder. The nanocrystalline iron powders, with an average particle diameter of 20 nm, were obtained via the sol-gel method. Scanning electron microscopy, energy dispersive X-ray spectroscopy and distribution maps show that the iron particle surface is covered with a thin layer of Mn-Zn ferrites. Mn-Zn ferrite uniformly coated the surface of the powder particles, resulting in a reduced imaginary permeability, increased electrical resistivity and a higher operating frequency of the synthesized magnets. Mn-Zn ferrite coated samples have higher permeability and lower magnetic loss when compared with the non-magnetic epoxy resin coated compacts. The real part of permeability increases by 33.5% when compared with the epoxy resin coated samples at 10 kHz. The effects of heat treatment temperature on crystalline phase formation and on the magnetic properties of the Mn-Zn ferrite were investigated via X-ray diffraction and a vibrating sample magnetometer. Ferrites decomposed to FeO and MnO after annealing above 400 °C in nitrogen; thus it is the optimum annealing temperature to attain the desired permeability.

Effect of synthesis route on electrical and ethanol sensing characteristics for LaFeO3-δ nanoparticles by citric sol-gel method

NASA Astrophysics Data System (ADS)

Cao, Ensi; Yang, Yuqing; Cui, Tingting; Zhang, Yongjia; Hao, Wentao; Sun, Li; Peng, Hua; Deng, Xiao

2017-01-01

LaFeO3-δ nanoparticles were prepared by citric sol-gel method with different raw material choosing and calcination process. The choosing of polyethylene glycol instead of ethylene glycol as raw material and additional pre-calcination at 400 °C rather than direct calcination at 600 °C could result in the decrease of resistance due to the reduction of activation energy Ea. Meanwhile, the choosing of ethylene glycol as raw material and additional pre-calcination leads to the enhancement of sensitivity to ethanol. Comprehensive analysis on the sensitivity and XRD, SEM, TEM, XPS results indicates that the sensing performance of LaFeO3-δ should be mainly determined by the adsorbed oxygen species on Fe ions, with certain contribution from native active oxygen. The best sensitivity of 46.1-200 ppm ethanol at prime working temperature of 112 °C is obtained by the sample using ethylene glycol as raw material with additional pre-calcination, which originates from its uniformly-sized and well-dispersed particles as well as high atomic ratio of Fe/La at surface region.

Effect of solvents on sol-gel spin-coated nanostructured Al-doped ZnO thin films: a film for key optoelectronic applications

NASA Astrophysics Data System (ADS)

Kumar, K. Deva Arun; Valanarasu, S.; Kathalingam, A.; Ganesh, V.; Shkir, Mohd.; AlFaify, S.

2017-12-01

Aluminum-doped zinc oxide (AZO) thin films were deposited by sol-gel spin coating technique onto the glass substrates using different solvents such as 2-methoxyethanol, methanol, ethanol and isopropanol. Prepared films were characterized by XRD, Raman spectrum, SEM, UV-visible spectrophotometer, photoluminescence (PL) and electrical studies. XRD studies showed that all the prepared films are hexagonal wurtzite structure with polycrystalline nature oriented along (002) direction. SEM images showed uniform particles of size around 60 nm distributed regularly on to the entire glass substrate. EDX analysis confirmed the composition of grown AZO film consisting of Al, Zn and O elements. The prepared films showed highest optical transmittance 94% in the visible range and band gap 3.30 eV. PL spectra for all AZO films showed a strong UV emission peak at 387 nm. The AZO films prepared using isopropanol solvent showed high carrier concentration and low resistivity values as 1.72 × 1020 cm-3 and 2.90 × 10-3 Ω cm, respectively, with high figure of merit ( ϕ) value 8.42 × 10-3 (Ω/sq)-1.

Effect of both deposition temperature and indium doping on the properties of sol-gel dip-coated SnO2 films.

PubMed

Caglar, Mujdat; Atar, Kadir Cemil

2012-10-01

Using indium chloride as an In source, In-doped SnO(2) films were fabricated by sol-gel method through dip-coating on borofloat glass substrates. The undoped SnO(2) films were deposited in air between 400 and 600 °C to get optimum deposition temperature in terms of crystal quality and hence In-doped SnO(2) films were deposited in air at 600 °C. The effect of both deposition temperature and In content on structural, morphological, optical and electrical properties was investigated. The crystalline structure and orientation of the films were investigated by X-ray diffraction (XRD) and surface morphology was studied by a field emission scanning electron microscope (FESEM). The compositional analysis of the films was confirmed by energy dispersive X-ray spectrometer (EDS). The absorption band edge of the SnO(2) films shifted from 3.88 to 3.66 eV with In content. The van der Pauw method was used to measure the sheet resistance of the films. The sheet resistance was affected significantly by deposition temperature and In content. Copyright © 2012 Elsevier B.V. All rights reserved.

Outdoor weathering of sol-gel-treated wood

Treesearch

Mandla A Tshabalala; Ryan Libert; Nancy Ross Sutherland

2009-01-01

Outdoor weathering of wood specimens treated with sol-gel formulations based on methyltrimethoxysilane (MTMOS), hexadecyltrimethoxysilane (HDTMOS), and ferric-zirconia-titania (Fe-Zr-Ti) sol was evaluated. The sol-gel process allowed deposition of a thin film of hybrid inorganic-organic networks (gel) in the wood cell wall that resulted in improved outdoor weathering...

76 FR 29290 - Medical Review Board Public Meeting; Correction and Republication

Federal Register 2010, 2011, 2012, 2013, 2014

2011-05-20

.... Do not submit the same comments by more than one method. Federal eRulemaking Portal: Go to http:[sol][sol]www.regulations.gov. Search docket number FMCSA-2011- 0131, and follow the online instructions for... at http:[sol][sol]www.regulations.gov, including any personal information provided. Please refer to...

Green synthesis of Au nanostructures at room temperature using biodegradable plant surfactants

EPA Science Inventory

One-step green synthesis of gold (Au) nanostructures is described using naturally occurring biodegradable plant surfactants such as VeruSOL-3™ (mixture of d-limonene and plant-based surfactants), VeruSOL-10™, VeruSOL-11™ and VeruSOL-12™ (individual plant-based surfactants deri...

SolTrace | Concentrating Solar Power | NREL

Science.gov Websites

NREL packaged distribution or from source code at the SolTrace open source project website. NREL Publications Support FAQs SolTrace open source project The code uses Monte-Carlo ray-tracing methodology. The -tracing capabilities. With the release of the SolTrace open source project, the software has adopted

Studies of (3-mercaptopropyl)trimethoxylsilane and bis(trimethoxysilyl)ethane sol-gel coating on copper and aluminum.

PubMed

Li, Ying-Sing; Lu, Weijie; Wang, Yu; Tran, Tuan

2009-09-01

Bis(trimethoxysilyl)ethane (BTMSE) and (3-mercaptopropyl)trimethoxysilane (MPTMS) have been used as precursors to prepare sol-gels and hybrid sol-gel under acidic condition. From the X-ray photoelectron spectroscopy data on MPTMS sol-gel coated aluminum and copper, it has been shown that the silane film is covalently bonded to Al surface through the interfacial condensation. There is no evidence of bonding interaction between the thiol group and the Cu. The recorded reflection adsorption IR (RAIR) spectrum has provided evidence that the coating BTMSE film covalently interacts with Al. Vibrational assignments have been suggested for pure BTMSE, BTMSE sol-gel, BTMSE xerogel, and BTMSE coated Al panel based on the group frequencies and the variation of frequencies with the sample treatment conditions. The progression of condensation reaction has been observed from the IR spectra of the BTMSE sol-gel and the sol-gel coated film after the treatments at different temperatures with different lengths of time. The corrosion protection of the sol-gel coated Al and Cu has been characterized in NaCl solutions by cyclic voltammetric, potentiodynamic polarization and impedance spectroscopy methods. All these electrochemical measurements indicate that the sol-gel coated metals have better corrosion protection than the corresponding uncoated metals.

Sol-gel open tubular ODS columns with reversed electroosmotic flow for capillary electrochromatography.

PubMed

Hayes, J D; Malik, A

2001-03-01

Sol-gel chemistry was successfully used for the fabrication of open tubular columns with surface-bonded octadecylsilane (ODS) stationary-phase coating for capillary electrochromatography (OT-CEC). Following column preparations, a series of experiments were performed to investigate the performance of the sol-gel coated ODS columns in OT-CEC. The incorporation of N-octadecyldimethyl[3-(trimethoxysilyl)propyl]ammonium chloride as one of the sol-gel precursors played an important role in the electrochromatographic performance of the prepared columns. This chemical reagent possesses a chromatographically favorable, bonded ODS moiety, in conjunction with three methoxy groups allowing for sol-gel reactivity. In addition, a positively charged nitrogen atom is present in the molecular structure of this reagent and provides a positively charged capillary surface responsible for the reversed electroosmotic flow (EOF) in the columns during CEC operation. Comparative studies involving the EOF within such sol-gel ODS coated and uncoated capillaries were performed using acetonitrile and methanol as the organic modifiers in the mobile phase. The use of a deactivating reagent, phenyldimethylsilane, in the sol-gel solution was evaluated. Efficiency values of over 400,000 theoretical plates per meter were achieved in CEC on a 64 cm x 25 microm i.d. sol-gel ODS open tubular column. Test mixtures of polycyclic aromatic hydrocarbons, benzene derivatives, and aromatic aldehydes and ketones were used to evaluate the CEC performances of both nondeactivated and deactivated open tubular sol-gel columns. The effects of mobile-phase organic modifier contents and pH on EOF in such columns were evaluated. The prepared sol-gel ODS columns are characterized by switchable electroosmotic flow. A pH value of approximately 8.5 was found correspond to the isoelectric point for the prepared sol-gel ODS coatings.

All optical controlled photonic integrated circuits using azo dye functionized sol-gel material

NASA Astrophysics Data System (ADS)

Ke, Xianjun

The main focus of this dissertation is development and characterization of all-optical controllable azo dye functionized sol gel material, demonstrating a PIC fabrication technique on glass substrate using such material, and exploration and feasibility demonstration of three PIC functional devices namely optical variable attenuator, optical switches, and optical tunable filters using the material. The realization of all the devices in this dissertation are based on one material: dye functionalized sol-gel material. A photochromic sol-gel material functionalized with azo dye was synthesized and characterized. It possesses a photochromic characteristic under the control of green laser beam illumination. The material characteristics suggest the possibility of a new promising material platform candidate for the fabrication of alloptical controlled photonic integrated circuits. As the first potential application of the dye functionalized sol-gel material, an alloptical variable attenuator was designed and demonstrated. The optical variable attenuation is achieved in Mach-Zehnder interferometric configuration through all-optical modulation of sol-gel waveguide phase shifters. A 2 x 2 optical switch based on multimode interference (MMI) waveguide structure is proposed in the dissertation. The schematic configuration of the optical switch consists of a cascade of two identical MMIs with two all-optical controlled phase shifters realized by using the photochromic sol-gel material. The cross or bar switch state of the optical switch is determined by the phase difference between the two sol-gel waveguide phase shifters. An all-optical tunable filter is designed and its feasibility demonstrated by using the sol-gel photochromic material. Except for the phase change demonstrated on sol-gel waveguide phase shifters, dynamic gratings were observed on sol-gel film when exposed to two interference beams. This reveals the possibility of realizing Bragg grating-based tunable filters. The schematic configuration of proposed tunable filters consists of a single straight waveguide embedded with a sol-gel waveguide. The wavelength tuning of the tunable filters is accomplished by varying the grating period.

Rheology of polyaniline-dinonylnaphthalene disulfonic acid (DNNDSA) montmorillonite clay nanocomposites in the sol state: shear thinning versus pseudo-solid behavior.

PubMed

Garai, Ashesh; Nandi, Arun K

2008-04-01

The melt rheology of polyaniline (PANI)-dinonylnaphthalenedisulfonic acid (DNNDSA) gel nanocomposites (GNCs) with organically modified (modified with cetyl trimethylammonium bromide)-montmorillonite (om-MMT) clay has been studied for three different clay concentrations at the temperature range 120-160 degrees C. Field emission scanning electron microscopy (FE-SEM), wide angle X-ray scattering (WAXS), differential scanning calorimetry (DSC) and dc-conductivity data (approximately 10(-3) S/cm) indicate that the PANI-DNNDSA melt is in sol state and it is not de-doped at that condition. The WAXS data indicate that in GNC-1 sol clay tactoids are in exfoliated state but in the other sols they are in intercalated state. The zero shear viscosity (eta0), storage modulus (G') and loss modulus (G") increase than that of pure gel in the GNCs. The pure sol and the sols of gel nanocomposites (GNCs) exhibit Newtonian behavior for low shear rate (< 6 x 10(-3) s(-1)) and power law variation for the higher shear rate region. The characteristic time (A) increase with increasing clay concentration and the power law index (n) decreases with increase in clay concentration in the GNCs indicating increased shear thinning for the clay addition. Thus the sols of om-clay nanocomposites of PANI-DNNDSA system are easily processible. The storage modulus (G') of GNC sols are higher than that of pure PANI-DNNDSA sol, GNC1 sol shows a maximum of 733% increase in storage modulus and the percent increase decreases with increase in temperature. Exfoliated nature of clay tactoids has been attributed for the above dramatic increase of G'. The PANI-DNNDSA sol nanocomposites behave as a pseudo-solid at higher frequency where G' and loss modulus (G") show a crossover point in the frequency sweep experiment at a fixed temperature. The crossover frequency decreases with increase in clay concentration and it increases with increase in temperature for GNC sols. The pseudo-solid behavior has been explained from jamming or network formation of clay tactoids under shear. A probable explanation of the two apparently contradictory phenomena of shear thinning versus pseudo-solid behavior of the nanocomposite sols is discussed.

A novel tantalum-based sol-gel packed microextraction syringe for highly specific enrichment of phosphopeptides in MALDI-MS applications.

PubMed

Çelikbıçak, Ömür; Atakay, Mehmet; Güler, Ülkü; Salih, Bekir

2013-08-07

A new tantalum-based sol-gel material was synthesized using a unique sol-gel synthesis pathway by PEG incorporation into the sol-gel structure without performing a calcination step. This improved its chemical and physical properties for the high capacity and selective enrichment of phosphopeptides from protein digests in complex biological media. The specificity of the tantalum-based sol-gel material for phosphopeptides was evaluated and compared with tantalum(V) oxide (Ta2O5) in different phosphopeptide enrichment applications. The tantalum-based sol-gel and tantalum(V) oxide were characterized in detail using FT-IR spectroscopy, X-ray diffraction (XRD) and scanning electron microscopy (SEM), and also using a surface area and pore size analyzer. In the characterization studies, the surface morphology, pore volume, crystallinity of the materials and PEG incorporation into the sol-gel structure to produce a more hydrophilic material were successfully demonstrated. The X-ray diffractograms of the two different materials were compared and it was noted that the broad signals of the tantalum-based sol-gel clearly represented the amorphous structure of the sol-gel material, which was more likely to create enough surface area and to provide more accessible tantalum atoms for phosphopeptides to be easily adsorbed when compared with the neat and more crystalline structure of Ta2O5. Therefore, the phosphopeptide enrichment performance of the tantalum-based sol-gels was found to be remarkably higher than the more crystalline Ta2O5 in our studies. Phosphopeptides at femtomole levels could be selectively enriched using the tantalum-based sol-gel and detected with a higher signal-to-noise ratio by matrix-assisted laser desorption/ionization-mass spectrometer (MALDI-MS). Moreover, phosphopeptides in a tryptic digest of non-fat bovine milk as a complex real-world biological sample were retained with higher yield using a tantalum-based sol-gel. Additionally, the sol-gel material was packed into a standard syringe (0.5 mL) to enhance the ease of use of the sol-gel material and for the elimination of additional mixing and separation procedures during the adsorption, washing and elution steps of the enrichment procedure. It was found that up to 28 phosphopeptides in milk digest were easily detectable by MALDI-MS at femtomole levels (around 20 fmol) using the microextraction syringe within less than one minute.

Transparent photocatalytic coatings on the surface of the tips of medical fibre-optic bundles

NASA Astrophysics Data System (ADS)

Evstropiev, S. K.; Volynkin, V. M.; Kiselev, V. M.; Dukelskii, K. V.; Evstropyev, K. S.; Demidov, V. V.; Gatchin, Yu. A.

2017-12-01

We report the results of the development of the sol - gel method for obtaining thin, transparent (in the visible part of the spectrum) TiO2/MgO coatings on the surfaces of the tips of medical fibre-optic bundles. Such coatings are capable of generating singlet oxygen under the action of UV radiation and are characterised by high antibacterial activity.

Measurements of the parallel wavenumber of lower hybrid waves in the scrape-off layer of a high-density tokamak

NASA Astrophysics Data System (ADS)

Baek, S. G.; Wallace, G. M.; Shinya, T.; Parker, R. R.; Shiraiwa, S.; Bonoli, P. T.; Brunner, D.; Faust, I.; LaBombard, B. L.; Takase, Y.; Wukitch, S.

2016-05-01

In lower hybrid current drive (LHCD) experiments on tokamaks, the parallel wavenumber of lower hybrid waves is an important physics parameter that governs the wave propagation and absorption physics. However, this parameter has not been experimentally well-characterized in the present-day high density tokamaks, despite the advances in the wave physics modeling. In this paper, we present the first measurement of the dominant parallel wavenumber of lower hybrid waves in the scrape-off layer (SOL) of the Alcator C-Mod tokamak with an array of magnetic loop probes. The electric field strength measured with the probe in typical C-Mod plasmas is about one-fifth of that of the electric field at the mouth of the grill antenna. The amplitude and phase responses of the measured signals on the applied power spectrum are consistent with the expected wave energy propagation. At higher density, the observed k|| increases for the fixed launched k||, and the wave amplitude decreases rapidly. This decrease is correlated with the loss of LHCD efficiency at high density, suggesting the presence of loss mechanisms. Evidence of the spectral broadening mechanisms is observed in the frequency spectra. However, no clear modifications in the dominant k|| are observed in the spectrally broadened wave components, as compared to the measured k|| at the applied frequency. It could be due to (1) the probe being in the SOL and (2) the limited k|| resolution of the diagnostic. Future experiments are planned to investigate the roles of the observed spectral broadening mechanisms on the LH density limit problem in the strong single pass damping regime.

Electrical transport and thermoelectric properties of Ni-doped perovskite-type YCo1-x NixO3 (0 <= x <= 0.07) prepared by sol-gel process

NASA Astrophysics Data System (ADS)

Liu, Yi; Li, Hai-Jin; Zhang, Qing; Li, Yong; Liu, Hou-Tong

2013-05-01

Electrical transport and thermoelectric properties of Ni-doped YCo1-xNixO3(0 <= x <= 0.07), prepared by using the sol-gel process, are investigated in a temperature range from 100 to 780 K. The results show that with the increase of Ni doping content, the values of DC resistivity of YCo1-xNixO3 decrease, but carrier concentration increases. The temperature dependences of the resistivity for YCo1-xNixO3 are found to follow a relation of ln ρ ∝ 1/T in a low-temperature range (LTR) (T < ~ 304 K for x = 0; ~ 230 K < T < ~ 500 K for x = 0.02, 0.05, and 0.07) and high-temperature range (HTR) (T > ~ 655 K for all compounds), respectively. The estimated apparent activation energies for conduction Ea1 in LRT and Ea2 in HTR are both found to decrease monotonically with doping content increasing. At very low temperatures (T < ~230 K), Mott's law is observed for YCo1—xNixO3 (x >= 0.02), indicating that considerable localized states form in the heavy doping compounds. Although the Seebeck coefficient of the compound decreases after Ni doping, the power factor of YCo1-xNixO3 is enhanced remarkably in a temperature range from 300 to 740 K, i.e., a 6-fold increase is achieved at 500 K for YCo0.98Ni0.02O3, indicating that the high-temperature thermoelectric property of YCoO3 can be improved by partial substitution of Ni for Co.

Growth and magnetoelectric properties of (00l)-oriented La{sub 0.67}Sr{sub 0.33}MnO{sub 3}/PbZr{sub 0.52}Ti{sub 0.48}O{sub 3} heterostructure films

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

Yan, Fuxue, E-mail: yanfuxue@126.com; Han, Kai, E-

2017-02-15

C-axis oriented La{sub 0.67}Sr{sub 0.33}MnO{sub 3}(LSMO)/PbZr{sub 0.52}Ti{sub 0.48}O{sub 3}(PZT) films are fabricated successfully by sol-gel method on LaAlO{sub 3} (00l) substrates. The structure, composition and morphology of the films are investigated by X-ray diffractometer (XRD, θ-2θ scan, ω-scan and ϕ-scan), X-ray photoelectron spectroscope (XPS), field emission scanning electron microscope (FESEM) and high resolution transmission electron microscope (HRTEM). The electric and magnetic properties of randomly and c-axis oriented LSMO/PZT films are studied comparably using ferroelectric testing apparatus and physical property measurement system (PPMS). It is found that the epitaxial LSMO/PZT composite films show well controlled growth along c-axis, and much bettermore » magnetoelectric properties than the randomly oriented ones. The ME voltage coefficient increases from 23 mV cm{sup −1} Oe{sup −1} for the randomly oriented LSMO/PZT composite films to 52 mV cm{sup −1} Oe{sup −1} for c-axis oriented ones prepared using the low cost sol-gel method presented in this study, which shows high potential in promising applications. - Highlights: •Epitaxial LSMO/PZT films were fabricated successfully by sol-gel method on LAO (00l) substrate. •The prepared films exhibit well-defined multiferroic properties for the epitaxial LSMO/PZT films. •Epitaxial LSMO/PZT films show superior magnetoelectric properties to the randomly oriented ones.« less

EDGE2D-EIRENE modelling of near SOL E r: possible impact on the H-mode power threshold

NASA Astrophysics Data System (ADS)

Chankin, A. V.; Delabie, E.; Corrigan, G.; Harting, D.; Maggi, C. F.; Meyer, H.; Contributors, JET

2017-04-01

Recent EDGE2D-EIRENE simulations of JET plasmas showed a significant difference between radial electric field (E r) profiles across the separatrix in two divertor configurations, with the outer strike point on the horizontal target (HT) and vertical target (VT) (Chankin et al 2016 Nucl. Mater. Energy, doi: 10.1016/j.nme.2016.10.004). Under conditions (input power, plasma density) where the HT plasma went into the H-mode, a large positive E r spike in the near scrape-off layer (SOL) was seen in the code output, leading to a very large E × B shear across the separatrix over a narrow region of a fraction of a cm width. No such E r feature was obtained in the code solution for the VT configuration, where the H-mode power threshold was found to be twice as high as in the HT configuration. It was hypothesised that the large E × B shear across the separatrix in the HT configuration could be responsible for the turbulence suppression leading to an earlier (at lower input power) L-H transition compared to the VT configuration. In the present work these ideas are extended to cover some other experimental observations on the H-mode power threshold variation with parameters which typically are not included in the multi-machine H-mode power threshold scalings, namely: ion mass dependence (isotope H-D-T exchange), dependence on the ion ∇B drift direction, and dependence on the wall material composition (ITER-like wall versus carbon wall in JET). In all these cases EDGE2D-EIRENE modelling shows larger positive E r spikes in the near SOL under conditions where the H-mode power threshold is lower, at least in the HT configuration.

76 FR 38591 - National Emission Standards for Hazardous Air Pollutants: Secondary Lead Smelting; Extension of...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-07-01

... comments, identified by Docket ID No. EPA-HQ- OAR-2011-0344, by one of the following methods: http:[sol][sol]www.regulations.gov: Follow the on-line instructions for submitting comments. E-mail: a-and-r... and may be made available online at http:[sol][sol]www.regulations.gov, including any personal...

Sol-Gel deposition of inorganic alkoxides on wood surfaces to enhance their durability under exposure to sunlight and moisture

Treesearch

Mandla A. Tshabalala

2005-01-01

Wood specimens were coated with sol-gel deposits of aluminum isopropoxide, titanium isopropoxide, or zirconium propoxide in the presence of methytrimethoxysilane. Both zirconium propoxide and titanium isopropoxide sol-gel deposits reduced water sorption, whereas aluminum isopropoxide sol-gel deposit increased water sorption, compared with uncoated wood specimens. There...

Sol-gel processing with inorganic metal salt precursors

DOEpatents

Hu, Zhong-Cheng

2004-10-19

Methods for sol-gel processing that generally involve mixing together an inorganic metal salt, water, and a water miscible alcohol or other organic solvent, at room temperature with a macromolecular dispersant material, such as hydroxypropyl cellulose (HPC) added. The resulting homogenous solution is incubated at a desired temperature and time to result in a desired product. The methods enable production of high quality sols and gels at lower temperatures than standard methods. The methods enable production of nanosize sols from inorganic metal salts. The methods offer sol-gel processing from inorganic metal salts.

Integrated engine-generator concept for aircraft electric secondary power

NASA Technical Reports Server (NTRS)

Secunde, R. R.; Macosko, R. P.; Repas, D. S.

1972-01-01

The integrated engine-generator concept of locating an electric generator inside an aircraft turbojet or turbofan engine concentric with, and driven by, one of the main engine shafts is discussed. When properly rated, the generator can serve as an engine starter as well as a generator of electric power. The electric power conversion equipment and generator controls are conveniently located in the aircraft. Preliminary layouts of generators in a large engine together with their physical sizes and weights indicate that this concept is a technically feasible approach to aircraft secondary power.

Diversity of fuel sources for electricity generation in an evolving U.S. power sector

NASA Astrophysics Data System (ADS)

DiLuccia, Janelle G.

Policymakers increasingly have shown interest in options to boost the relative share of renewable or clean electricity generating sources in order to reduce negative environmental externalities from fossil fuels, guard against possible resource constraints, and capture economic advantages from developing new technologies and industries. Electric utilities and non-utility generators make decisions regarding their generation mix based on a number of different factors that may or may not align with societal goals. This paper examines the makeup of the electric power sector to determine how the type of generator and the presence (or lack) of competition in electricity markets at the state level may relate to the types of fuel sources used for generation. Using state-level electricity generation data from the U.S. Energy Information Administration from 1990 through 2010, this paper employs state and time fixed-effects regression modeling to attempt to isolate the impacts of state-level restructuring policies and the emergence of non-utility generators on states' generation from coal, from fossil fuel and from renewable sources. While the analysis has significant limitations, I do find that state-level electricity restructuring has a small but significant association with lowering electricity generation from coal specifically and fossil fuels more generally. Further research into the relationship between competition and fuel sources would aid policymakers considering legislative options to influence the generation mix.

78 FR 77343 - Small Business Size Standards: Utilities

Federal Register 2010, 2011, 2012, 2013, 2014

2013-12-23

... (such as solar, wind, biomass, geothermal) as well as other industries, where power generation is...: namely NAICS 221114 (Solar Electric Power Generation), NAICS 221115 (Wind Electric Power Generation... Electric Power 4 million 250 employees. Generation. megawatt hours. [[Page 77348

78 FR 36277 - Vogtle Electric Generating Plant, Unit 3

Federal Register 2010, 2011, 2012, 2013, 2014

2013-06-17

... NUCLEAR REGULATORY COMMISSION [Docket No. 52-025; NRC-2008-0252] Vogtle Electric Generating Plant....01, for the Vogtle Electric Generating Plant, Unit 3. ADDRESSES: Please refer to Docket ID NRC-2008... Generating Plant, Unit 3 [[Page 36278

Optically activated switches for the generation of complex electrical waveforms with multigigahertz bandwidth

NASA Astrophysics Data System (ADS)

Skeldon, Mark D.; Okishev, Andrey V.; Letzring, Samuel A.; Donaldson, William R.; Green, Kenton; Seka, Wolf D.; Fuller, Lynn F.

1995-01-01

An electrical pulse-generation system using two optically activated Si photoconductive switches can generate shaped electrical pulses with multigigahertz bandwidth. The Si switches are activated by an optical pulse whose leading edge is steepened by stimulated Brillouin scattering (SBS) in CCl4. With the bandwidth generated by the SBS process, a laser having a 1- to 3-ns pulse width is used to generate electrical pulses with approximately 80-ps rise times (approximately 4-GHz bandwidth). Variable impedance microstrip lines are used to generate complex electrical waveforms that can be transferred to a matched load with minimal loss of bandwidth.

Regulation of the sol Locus Genes for Butanol and Acetone Formation in Clostridium acetobutylicum ATCC 824 by a Putative Transcriptional Repressor

PubMed Central

Nair, Ramesh V.; Green, Edward M.; Watson, David E.; Bennett, George N.; Papoutsakis, Eleftherios T.

1999-01-01

A gene (orf1, now designated solR) previously identified upstream of the aldehyde/alcohol dehydrogenase gene aad (R. V. Nair, G. N. Bennett, and E. T. Papoutsakis, J. Bacteriol. 176:871–885, 1994) was found to encode a repressor of the sol locus (aad, ctfA, ctfB and adc) genes for butanol and acetone formation in Clostridium acetobutylicum ATCC 824. Primer extension analysis identified a transcriptional start site 35 bp upstream of the solR start codon. Amino acid comparisons of SolR identified a potential helix-turn-helix DNA-binding motif in the C-terminal half towards the center of the protein, suggesting a regulatory role. Overexpression of SolR in strain ATCC 824(pCO1) resulted in a solvent-negative phenotype owing to its deleterious effect on the transcription of the sol locus genes. Inactivation of solR in C. acetobutylicum via homologous recombination yielded mutants B and H (ATCC 824 solR::pO1X) which exhibited deregulated solvent production characterized by increased flux towards butanol and acetone formation, earlier induction of aad, lower overall acid production, markedly improved yields of solvents on glucose, a prolonged solvent production phase, and increased biomass accumulation compared to those of the wild-type strain. PMID:9864345

Spectroscopic studies of triethoxysilane sol-gel and coating process.

PubMed

Li, Ying-Sing; Ba, Abdul

2008-10-01

Silica sol-gels have been prepared under different conditions using triethoxysilane (TES) as precursor. The prepared sol-gels have been used to coat aluminum for corrosion protection. Vibrational assignments have been made for most vibration bands of TES, TES sol-gel, TES sol-gel-coated aluminum and xerogel. It has been noticed that air moisture may have helped the hydrolysis of the thin coating films. Xerogels have been obtained from the sol-gel under different temperature conditions and the resulting samples have been characterized by using infrared and Raman spectroscopic methods. IR data indicate that the sol-gel process is incomplete under the ambient conditions although an aqueous condition can have slightly improved the process. Two nonequivalent silicon atoms have been identified from the collected 29Si NMR spectra for the sol-gel, supporting the result derived from the IR data. The frequency of Si-H bending vibration has been found to be more sensitive to the skeletal structure than that of the Si-H stretching vibration. A higher temperature condition could favor the progression of hydrolysis and condensation. A temperature higher than 300 degrees C would cause sample decomposition without seriously damaging the silica network. From infrared intensity measurements and thermo-gravimetric analyses, the fractions of incomplete hydrolysis and condensation species have been estimated to be 4% and 3%, respectively. Electrochemical data have shown that the sol-gel coating significantly improves the corrosion protection properties of aluminum.

Effect of Chelating Agents on the Stability of Nano-TiO2 Sol Particles for Sol-Gel Coating.

PubMed

Maeng, Wan Young; Yoo, Mi

2015-11-01

Agglomeration of sol particles in a titanium alkoxide (tetrabutyl orthotitanate (TBOT), > 97%) solution during the hydrolysis and condensation steps makes the sol solution difficult to use for synthesizing homogeneous sol-gel coating. Here, we have investigated the effect of stabilizing agents (acetic acid and ethyl acetoacetate (EAcAc)) on the agglomeration of Ti alkoxide particles during hydrolysis and condensation in order to determine the optimized conditions for controlling the precipitation of TiO2 particles. The study was conducted at R(AC) ([acetic acid]/[TBOT]) = 0.1-5 and R(EAcAc)([EAcAc]/[TBOT]) = 0.05-0.65. We also studied the effects of a basic catalyst ethanolamine (ETA), water, and HCl on sol stability. The chelating ligands in the precursor sol were analyzed with FT-IR. The coating properties were examined by focused ion beam. The stabilizing agents (acetic acid and EAcAc) significantly influenced the agglomeration and precipitation of TBOT precursor particles during hydrolysis. As R(AC) and R(EAcAc) increased, the agglomeration remarkably decreased. The stability of the sol with acetic acid and EAcAc arises from the coordination of the chelating ligand to TBOT that hinders hydrolysis and condensation. A uniform fine coating (thickness: 30 nm) on stainless steel was obtained by using an optimized sol with R(AC) = 0.5 and R(EAcAc) = 0.65.

20 CFR 10.706 - How will a beneficiary know if OWCP or SOL has determined that action against a third party is...

Code of Federal Regulations, 2010 CFR

2010-04-01

... 20 Employees' Benefits 1 2010-04-01 2010-04-01 false How will a beneficiary know if OWCP or SOL... Third Party Liability § 10.706 How will a beneficiary know if OWCP or SOL has determined that action... is transferred to SOL, a second notification may be issued. ...

75 FR 70903 - Eastern North Pacific Gray Whale; Notice of Extension of Public Comment Period on Marine Mammal...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-11-19

...: Electronic Submissions: Submit all electronic public comments via the Federal eRulemaking Portal http:[sol][sol]www.regulations.gov. Fax: 301-713-0376, Attn: Chief, Marine Mammal and Sea Turtle Conservation... are a part of the public record and will generally be posted to http:[sol][sol]www.regulations.gov...

Sol-gel modification of wood substrates to retard weathering

Treesearch

Mandla A Tshabalala; Sam Williams

2008-01-01

Wood specimens were treated with sol-gel systems based on metalorganic precursors of silicon (Si), iron (Fe), zirconium (Zr), and titanium (Ti). The effect of these sol-gel systems on weathering properties of wood was investigated. These sol-gel systems were found to have a positive effect on surface color stability and water vapor resistance of the specimens. Under...

Nuclear electric generation: Political, social, and economic cost and benefit to Indonesia. Master`s thesis

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

Waliyo

Indonesia, the largest archipelagic country with a population the fourth biggest in the world, is now in the process of development. It needs a large quantity of energy electricity to meet the industrial and household demands. The currently available generating capacity is not sufficient to meet the electricity demand for the rapidly growing industries and the increasing population. In order to meet the future demand for electricity, new generating capacity is required to be added to the current capacity. Nuclear electricity generation is one possible alternative to supplement Indonesia`s future demand of electricity. This thesis investigates the possibility of developingmore » nuclear electricity generation in Indonesia, considering the political, social, and economic cost and benefit to Indonesia.« less

Controlled release of vancomycin from thin sol-gel films on implant surfaces successfully controls osteomyelitis.

PubMed

Adams, Christopher S; Antoci, Valentin; Harrison, Gerald; Patal, Payal; Freeman, Terry A; Shapiro, Irving M; Parvizi, Javad; Hickok, Noreen J; Radin, Shula; Ducheyne, Paul

2009-06-01

Peri-prosthetic infection remains a serious complication of joint replacement surgery. Herein, we demonstrate that a vancomycin-containing sol-gel film on Ti alloy rods can successfully treat bacterial infections in an animal model. The vancomycin-containing sol-gel films exhibited predictable release kinetics, while significantly inhibiting S. aureus adhesion. When evaluated in a rat osteomyelitis model, microbiological analysis indicated that the vancomycin-containing sol-gel film caused a profound decrease in S. aureus number. Radiologically, while the control side showed extensive bone degradation, including abscesses and an extensive periosteal reaction, rods coated with the vancomycin-containing sol-gel film resulted in minimal signs of infection. MicroCT analysis confirmed the radiological results, while demonstrating that the vancomycin-containing sol-gel film significantly protected dense bone from resorption and minimized remodeling. These results clearly demonstrate that this novel thin sol-gel technology can be used for the targeted delivery of antibiotics for the treatment of periprosthetic as well as other bone infections. Copyright 2008 Orthopaedic Research Society

Thermodynamic analysis of sol-gel transition of gelatin in terms of water activity in various solutions.

PubMed

Miyawaki, Osato; Omote, Chiaki; Matsuhira, Keiko

2015-12-01

Sol-gel transition of gelatin was analyzed as a multisite stoichiometric reaction of a gelatin molecule with water and solute molecules. The equilibrium sol-gel transition temperature, Tt , was estimated from the average of gelation and melting temperature measured by differential scanning calorimetry. From Tt and the melting enthalpy, ΔHsol , the equilibrium sol-to-gel ratio was estimated by the van't Hoff equation. The reciprocal form of the Wyman-Tanford equation, which describes the sol-to-gel ratio as a function of water activity, was successfully applied to obtain a good linear relationship. From this analysis, the role of water activity on the sol-gel transition of gelatin was clearly explained and the contributions of hydration and solute binding to gelatin molecules were separately discussed in sol-gel transition. The general solution for the free energy for gel-stabilization in various solutions was obtained as a simple function of solute concentration. © 2015 Wiley Periodicals, Inc.