How social learning adds up to a culture: from birdsong to human public opinion

PubMed Central

Feher, Olga; Fimiarz, Daniel; Conley, Dalton

2017-01-01

ABSTRACT Distributed social learning may occur at many temporal and spatial scales, but it rarely adds up to a stable culture. Cultures vary in stability and diversity (polymorphism), ranging from chaotic or drifting cultures, through cumulative polymorphic cultures, to stable monolithic cultures with high conformity levels. What features can sustain polymorphism, preventing cultures from collapsing into either chaotic or highly conforming states? We investigate this question by integrating studies across two quite separate disciplines: the emergence of song cultures in birds, and the spread of public opinion and social conventions in humans. In songbirds, the learning process has been studied in great detail, while in human studies the structure of social networks has been experimentally manipulated on large scales. In both cases, the manner in which communication signals are compressed and filtered – either during learning or while traveling through the social network – can affect culture polymorphism and stability. We suggest a simple mechanism of a shifting balance between converging and diverging social forces to explain these effects. Understanding social forces that shape cultural evolution might be useful for designing agile communication systems, which are stable and polymorphic enough to promote gradual changes in institutional behavior. PMID:28057835

General and simple approach for control cage and cylindrical mesopores, and thermal/hydrothermal stable frameworks.

PubMed

El-Safty, Sherif A; Mizukami, Fujio; Hanaoka, Takaaki

2005-05-19

Highly ordered cage and cylindrical mesoporeous silica monoliths (HOM) with 2- and 3-dimensional (2D and 3D, respectively) structures, mesopore/micropore volumes, and thick-walled frameworks were successfully fabricated by instant direct templating of lyotropic phases of copolymer (EO(m)-PO(n)-EO(m)) surfactants. Large cage-like pores with uniform constriction sizes up to 10 nm and open cylindrical channel-like mesopores can be easily achieved by this simple and efficient synthesis design. Our results show that the cage-like pores could be fabricated at relatively lower copolymer concentrations used in the lyotropic phase domains at copolymer/TMOS ratios of 35 wt %. These ordered cage pore architectures underwent transition to open-cylindrical pores by increasing the copolymer concentration. High EO/PO block copolymers, in general, were crucially affected on the increase of the interior cavity sizes and on the stability of the cage mesopore characters. However, for F108 (EO(141)PO(44)EO(141)) systems, the fabrication of ordered and stable cage pore monoliths was achieved with significantly higher copolymer concentrations up to 90 wt %. Interestingly, the effective copolymer molecular nature was also observed in the ability to design various ordered mesophase geometries in large domain sizes. Our findings here show evidence that the synthetic strategy provides realistic control over a wide range of mesostructured phase geometries and their extended long-range ordering in the final replicas of the silica monolith frameworks. In addition, the HOM silica monoliths exhibited considerable structural stability against higher thermal temperature (up to 1000 degrees C) and longer hydrothermal treatment times under boiling water and steam. The remarkable structural findings of 3D frameworks, transparent monoliths, and micropores combined with large cage- and cylindrical-like mesopores are expected to find promising uses in materials chemistry.

Guided-wave photodiode using through-absorber quantum-well-intermixing and methods thereof

DOEpatents

Skogen, Erik J.

2016-10-25

The present invention includes a high-speed, high-saturation power detector (e.g., a photodiode) compatible with a relatively simple monolithic integration process. In particular embodiments, the photodiode includes an intrinsic bulk absorption region, which is grown above a main waveguide core including a number of quantum wells (QWs) that are used as the active region of a phase modulator. The invention also includes methods of fabricating integrated photodiode and waveguide assemblies using a monolithic, simplified process.

What sets the central structure of dark matter haloes?

NASA Astrophysics Data System (ADS)

Ogiya, Go; Hahn, Oliver

2018-02-01

Dark matter (DM) haloes forming near the thermal cut-off scale of the density perturbations are unique, since they are the smallest objects and form through monolithic gravitational collapse, while larger haloes contrastingly have experienced mergers. While standard cold dark matter (CDM) simulations readily produce haloes that follow the universal Navarro-Frenk-White (NFW) density profile with an inner slope, ρ ∝ r-α, with α = 1, recent simulations have found that when the free-streaming cut-off expected for the CDM model is resolved, the resulting haloes follow nearly power-law density profiles of α ∼ 1.5. In this paper, we study the formation of density cusps in haloes using idealized N-body simulations of the collapse of proto-haloes. When the proto-halo profile is initially cored due to particle free-streaming at high redshift, we universally find ∼r-1.5 profiles irrespective of the proto-halo profile slope outside the core and large-scale non-spherical perturbations. Quite in contrast, when the proto-halo has a power-law profile, then we obtain profiles compatible with the NFW shape when the density slope of the proto-halo patch is shallower than a critical value, αini ∼ 0.3, while the final slope can be steeper for αini ≳ 0.3. We further demonstrate that the r-1.5 profiles are sensitive to small-scale noise, which gradually drives them towards an inner slope of -1, where they become resilient to such perturbations. We demonstrate that the r-1.5 solutions are in hydrostatic equilibrium, largely consistent with a simple analytic model, and provide arguments that angular momentum appears to determine the inner slope.

High-throughput, automated extraction of DNA and RNA from clinical samples using TruTip technology on common liquid handling robots.

PubMed

Holmberg, Rebecca C; Gindlesperger, Alissa; Stokes, Tinsley; Brady, Dane; Thakore, Nitu; Belgrader, Philip; Cooney, Christopher G; Chandler, Darrell P

2013-06-11

TruTip is a simple nucleic acid extraction technology whereby a porous, monolithic binding matrix is inserted into a pipette tip. The geometry of the monolith can be adapted for specific pipette tips ranging in volume from 1.0 to 5.0 ml. The large porosity of the monolith enables viscous or complex samples to readily pass through it with minimal fluidic backpressure. Bi-directional flow maximizes residence time between the monolith and sample, and enables large sample volumes to be processed within a single TruTip. The fundamental steps, irrespective of sample volume or TruTip geometry, include cell lysis, nucleic acid binding to the inner pores of the TruTip monolith, washing away unbound sample components and lysis buffers, and eluting purified and concentrated nucleic acids into an appropriate buffer. The attributes and adaptability of TruTip are demonstrated in three automated clinical sample processing protocols using an Eppendorf epMotion 5070, Hamilton STAR and STARplus liquid handling robots, including RNA isolation from nasopharyngeal aspirate, genomic DNA isolation from whole blood, and fetal DNA extraction and enrichment from large volumes of maternal plasma (respectively).

Control of the collapse distance in atmospheric propagation

NASA Astrophysics Data System (ADS)

Fibich, Gadi; Sivan, Yonatan; Ehrlich, Yosi; Louzon, Einat; Fraenkel, Moshe; Eisenmann, Shmuel; Katzir, Yiftach; Zigler, Arie

2006-06-01

We show experimentally for ultrashort laser pulses propagating in air, that the collapse/filamentation distance of intense laser pulses in the atmosphere can be extended and controlled with a simple double-lens setup. We derive a simple formula for the filamentation distance, and confirm its agreement with the experimental results. We also observe that delaying the onset of filamentation increases the filament length.

Saltwater intrusion coupled with drought accelerates carbon loss from a brackish coastal wetland

NASA Astrophysics Data System (ADS)

Wilson, B.; Troxler, T.

2017-12-01

Coastal wetlands, such as the Everglades, are critical ecosystems for blue carbon (C) storage, yet this storage capacity is vulnerable to environmental change, such as saltwater intrusion and altered hydrology. Saltwater intrusion can stress vegetation and bring new metabolites for microbial respiration, thereby altering the C cycle. Drought can reduce the depth of water covering the wetland soil, and, in extreme cases, lead to exposed soil surface. This increases oxygen levels, thus speeding up C decomposition and potentially leading to peat collapse. The combined effects of both saltwater intrusion and drought on coastal marshes, however, are still uncertain, but recent evidence suggests that saltwater intrusion accelerates C loss from wetlands when coupled with drought. Our objective was to determine the change in CO2 flux, decomposition, root and shoot production, and elevation in a brackish water marsh under conditions of drought and elevated salinity. During the onset of drought, soil CO2 efflux increased by 124% and 237% in the ambient and elevated salinity treatments, respectively, compared to the control. Within one month, elevated salinity decreased net ecosystem production (NEP) by 40%, while after 6 months it had decreased by 85%. During the onset of the drought, there was no difference in NEP with ambient salinity between the inundated and exposed monoliths (-3.4 ± 0.8 vs. -4.2 ± 2.0 μmol CO2 m-2 s-1, respectively). However, drought conditions in the elevated salinity treatment resulted in more CO2 release in the exposed monoliths than the inundated monoliths (1.5 ± 0.4 vs. -0.5 ± 0.3 μmol CO2 m-2 s-1, respectively). Elevation change collected at the end of the experiment will allow us to test if elevated salinity combined with drought contributes to peat collapse, and what mechanisms of ecosystem C cycling has the greatest influence. While the restoration of water flows to the southern Everglades is hypothesized to mitigate the periods of drought and slow down saltwater intrusion, this restoration has not occurred yet. Given accelerating sea level rise, increasing frequencies of saltwater intrusion coupled with drought could accelerate C loss from these coastal marshes.

InP-based compact transversal filter for monolithically integrated light source array.

PubMed

Ueda, Yuta; Fujisawa, Takeshi; Takahata, Kiyoto; Kohtoku, Masaki; Ishii, Hiroyuki

2014-04-07

We developed an InP-based 4x1 transversal filter (TF) with multi-mode interference couplers (MMIs) as a compact wavelength multiplexer (MUX) 1700 μm x 400 μm in size. Furthermore, we converted the MMI-based TF to a reflection type to obtain an ultra-compact MUX of only 900 μm x 50 μm. These MUXs are made with a simple fabrication process and show a satisfactory wavelength filtering operation as MUXs of monolithically integrated light source arrays, for example, for 100G bit Ethernet.

Simple practical approach for sample loading prior to DNA extraction using a silica monolith in a microfluidic device.

PubMed

Shaw, Kirsty J; Joyce, Domino A; Docker, Peter T; Dyer, Charlotte E; Greenman, John; Greenway, Gillian M; Haswell, Stephen J

2009-12-07

A novel DNA loading methodology is presented for performing DNA extraction on a microfluidic system. DNA in a chaotropic salt solution was manually loaded onto a silica monolith orthogonal to the subsequent flow of wash and elution solutions. DNA was successfully extracted from buccal swabs using electro-osmotic pumping (EOP) coupled with in situ reagents contained within a 1.5% agarose gel matrix. The extracted DNA was of sufficient quantity and purity for polymerase chain reaction (PCR) amplification.

Collapse limit states of reinforced earth retaining walls

NASA Astrophysics Data System (ADS)

Bolton, M. D.; Pang, P. L. R.

The use of systems of earth reinforcement or anchorage is gaining in popularity. It therefore becomes important to assess whether the methods of design which were adopted for such constructions represent valid predictions of realistic limit states. Confidence can only be gained with regard to the effectiveness of limit state criteria if a wide variety of representative limit states were observed. Over 80 centrifugal model tests of simple reinforced earth retaining walls were carried out, with the main purpose of clarifying the nature of appropriate collapse criteria. Collapses due to an insufficiency of friction were shown to be repeatable and therefore subject to fairly simple limit state calculations.

Development and Evaluation of High Bioavailable Sustained-Release Nimodipine Tablets Prepared with Monolithic Osmotic Pump Technology.

PubMed

Kong, Hua; Yu, Fanglin; Liu, Yan; Yang, Yang; Li, Mingyuan; Cheng, Xiaohui; Hu, Xiaoqin; Tang, Xuemei; Li, Zhiping; Mei, Xingguo

2018-01-01

Frequent administration caused by short half-life and low bioavailability due to poor solubility and low dissolution rate limit the further application of poorly water-soluble nimodipine, although several new indications have been developed. To overcome these shortcomings, sophisticated technologies had to be used since the dose of nimodipine was not too low and the addition of solubilizers could not resolve the problem of poor release. The purpose of this study was to obtain sustained and complete release of nimodipine with a simple and easily industrialized technology. The expandable monolithic osmotic pump tablets containing nimodipine combined with poloxamer 188 and carboxymethylcellulose sodium were prepared. The factors affecting drug release including the amount of solubilizing agent, expanding agent, retarding agent in core tablet and porogenic agent in semipermeable film were optimized. The release behavior was investigated both in vitro and in beagle dogs. It was proved that the anticipant release of nimodipine could be realized in vitro. The sustained and complete release of nimodipine was also realized in beagles because the mean residence time of nimodipine from the osmotic pump system was longer and Cmax was lower than those from the sustained-release tablets in market while there was no difference in AUC(0-t) of the monolithic osmotic pump tablets and the sustained release tablets in market. It was reasonable to believe that the sustained and complete release of poorly watersoluble nimodipine could be realized by using simple expandable monolithic osmotic pump technology combined with surfactant. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Determination of azithromycin residue in pork using a molecularly imprinted monolithic microcolumn coupled to liquid chromatography with tandem mass spectrometry.

PubMed

Zhou, Tong; Yang, Haicui; Jin, Zhen; Liu, Qingying; Song, Xuqin; He, Limin; Fang, Binghu; Meng, Chenying

2016-04-01

Using spiramycin as a dummy template, a molecularly imprinted polymer monolithic micro-column with high selection to azithromycin was prepared in a micropipette tip. The imprinting factor of the monolithic micro-column prepared was approximately 2.67 and the morphological structure of the polymers was characterized by scanning electron microscopy. A simple, sensitive, and reproducible method based on the imprinted monolithic micro-column coupled to liquid chromatography with tandem mass spectrometry was developed for determining the residues of azithromycin in pork. Pork samples were extracted with acetonitrile, cleaned up under the optimal monolithic micro-column conditions, and analyzed using liquid chromatography with tandem mass spectrometry in the multiple reaction monitoring mode. The assay exhibited a linear dynamic range of 0.50-50 μg/L with the correlation coefficient (r(2) ) above 0.99. In the three spiking levels of 0.50, 1.0, and 10 μg/kg, the average recoveries of azithromycin from pork samples were between 85.8 and 96.5% with a relative standard deviation below 10%. The limit of detection and limit of quantitation were 0.03 and 0.1 μg/kg, respectively. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Coupling of metal-organic frameworks-containing monolithic capillary-based selective enrichment with matrix-assisted laser desorption ionization-time-of-flight mass spectrometry for efficient analysis of protein phosphorylation.

PubMed

Li, Daojin; Yin, Danyang; Chen, Yang; Liu, Zhen

2017-05-19

Protein phosphorylation is a major post-translational modification, which plays a vital role in cellular signaling of numerous biological processes. Mass spectrometry (MS) has been an essential tool for the analysis of protein phosphorylation, for which it is a key step to selectively enrich phosphopeptides from complex biological samples. In this study, metal-organic frameworks (MOFs)-based monolithic capillary has been successfully prepared as an effective sorbent for the selective enrichment of phosphopeptides and has been off-line coupled with matrix-assisted laser desorption ionization-time-of-flight mass spectrometry (MALDI-TOF MS) for efficient analysis of phosphopeptides. Using š-casein as a representative phosphoprotein, efficient phosphorylation analysis by this off-line platform was verified. Phosphorylation analysis of a nonfat milk sample was also demonstrated. Through introducing large surface areas and highly ordered pores of MOFs into monolithic column, the MOFs-based monolithic capillary exhibited several significant advantages, such as excellent selectivity toward phosphopeptides, superb tolerance to interference and simple operation procedure. Because of these highly desirable properties, the MOFs-based monolithic capillary could be a useful tool for protein phosphorylation analysis. Copyright © 2016 Elsevier B.V. All rights reserved.

Extraction and Determination of Quercetin from Ginkgo biloba by DESs-Based Polymer Monolithic Cartridge.

PubMed

Wang, Xiaoqin; Li, Guizhen; Ho Row, Kyung

2017-09-01

Deep eutectic solvents (DES) were formed from choline chloride (ChCl). DES-modified polymer monolithic (DES-M), template molecular polymer monolithic and non-DES-M without a molecular template were synthesized in identical process. These polymer materials were characterized by field emission scanning electron microscopy and Fourier transform infrared spectroscopy. The significant selective adsorption properties of the polymers were assessed by an absorption capacity experiment and solid-phase extraction (SPE). The optimized extraction procedure was as follows: ultrasonic time (30 min), optimal solvent (ethanol) and liquid to material ratio (20 mL g-1). Under this condition, the amount of quercetin extracted from Ginkgo biloba was 290.8 mg g-1. The purification of G. biloba was achieved by the SPE process. Based on the results, DESs-based monolithic cartridges can be used for simple and efficient extraction and as a pre-concentration technique for the purification of bioactive compounds or drugs in aqueous environments with high affinity and selectivity. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

How social learning adds up to a culture: from birdsong to human public opinion.

PubMed

Tchernichovski, Ofer; Feher, Olga; Fimiarz, Daniel; Conley, Dalton

2017-01-01

Distributed social learning may occur at many temporal and spatial scales, but it rarely adds up to a stable culture. Cultures vary in stability and diversity (polymorphism), ranging from chaotic or drifting cultures, through cumulative polymorphic cultures, to stable monolithic cultures with high conformity levels. What features can sustain polymorphism, preventing cultures from collapsing into either chaotic or highly conforming states? We investigate this question by integrating studies across two quite separate disciplines: the emergence of song cultures in birds, and the spread of public opinion and social conventions in humans. In songbirds, the learning process has been studied in great detail, while in human studies the structure of social networks has been experimentally manipulated on large scales. In both cases, the manner in which communication signals are compressed and filtered - either during learning or while traveling through the social network - can affect culture polymorphism and stability. We suggest a simple mechanism of a shifting balance between converging and diverging social forces to explain these effects. Understanding social forces that shape cultural evolution might be useful for designing agile communication systems, which are stable and polymorphic enough to promote gradual changes in institutional behavior. © 2017. Published by The Company of Biologists Ltd.

Seismic waves and earthquakes in a global monolithic model

NASA Astrophysics Data System (ADS)

Roubíček, Tomáš

2018-03-01

The philosophy that a single "monolithic" model can "asymptotically" replace and couple in a simple elegant way several specialized models relevant on various Earth layers is presented and, in special situations, also rigorously justified. In particular, global seismicity and tectonics is coupled to capture, e.g., (here by a simplified model) ruptures of lithospheric faults generating seismic waves which then propagate through the solid-like mantle and inner core both as shear (S) or pressure (P) waves, while S-waves are suppressed in the fluidic outer core and also in the oceans. The "monolithic-type" models have the capacity to describe all the mentioned features globally in a unified way together with corresponding interfacial conditions implicitly involved, only when scaling its parameters appropriately in different Earth's layers. Coupling of seismic waves with seismic sources due to tectonic events is thus an automatic side effect. The global ansatz is here based, rather for an illustration, only on a relatively simple Jeffreys' viscoelastic damageable material at small strains whose various scaling (limits) can lead to Boger's viscoelastic fluid or even to purely elastic (inviscid) fluid. Self-induced gravity field, Coriolis, centrifugal, and tidal forces are counted in our global model, as well. The rigorous mathematical analysis as far as the existence of solutions, convergence of the mentioned scalings, and energy conservation is briefly presented.

Preparation of poly(trimethyl-2-methacroyloxyethylammonium chloride-co-ethylene glycol dimethacrylate) monolith and its application in solid phase microextraction of brominated flame retardants.

PubMed

Yang, Ting-ting; Zhou, Lin-feng; Qiao, Jun-qin; Lian, Hong-zhen; Ge, Xin; Chen, Hong-yuan

2013-05-24

A capillary poly(trimethyl-2-methacroyloxyethylammonium chloride-co-ethylene glycol dimethacrylate) monolith was in situ synthesized by thermally initiated free radical co-polymerization using trimethyl-2-methacroyloxyethylammonium chloride (MATE) and ethylene glycol dimethacrylate (EGDMA) as functional monomer and cross-linker, respectively. N,N-dimethylformamide and polyethylene glycol 6000 were used as solvent and porogen, respectively. The morphology and porous structure of the resulting monoliths were assessed by scanning electron microscope. In order to prepare practically useful poly(MATE-co-EGDMA) monoliths with low flow resistance and good mechanical strength, some parameters such as PEG-6000 to DMF ratio, total monomer to porogen ratio, and crosslinker to monomer ratio were optimized systematically. Moreover, the extraction mechanism was evaluated using two series of compounds, alkylbenzenes and weak acids, as model compounds on poly(MATE-co-EGDMA) monoliths as liquid chromatographic stationary phase. Finally, the monoliths were applied as the solid phase microextraction medium, and a simple off-line method for simultaneous determination of three brominated flame retardants, 2,4,6-tribromophenol (TBP), tetrabromobisphenol A (TBBPA) and 4,4'-dibrominated diphenyl ether (DBDPE), in environmental waters was developed by coupling the polymer monolith microextraction to HPLC with UV detection. The regression equations for these three brominated flame retardants showed good linearity from their limit of quantification to 5000ng/mL. The limits of detection were 0.20, 0.15 and 0.10ng/mL for TBP, TBBPA and DBDPE, respectively. The recovery of the proposed method was 78.7-106.1% with intra-day relative standard deviation of 1.3-4.4%. Copyright © 2013 Elsevier B.V. All rights reserved.

Galactic Halo Stars in Phase Space: A Hint of Satellite Accretion?

NASA Astrophysics Data System (ADS)

Brook, Chris B.; Kawata, Daisuke; Gibson, Brad K.; Flynn, Chris

2003-03-01

The present-day chemical and dynamical properties of the Milky Way bear the imprint of the Galaxy's formation and evolutionary history. One of the most enduring and critical debates surrounding Galactic evolution is that regarding the competition between ``satellite accretion'' and ``monolithic collapse'' the apparent strong correlation between orbital eccentricity and metallicity of halo stars was originally used as supporting evidence for the latter. While modern-day unbiased samples no longer support the claims for a significant correlation, recent evidence has been presented by Chiba & Beers for the existence of a minor population of high-eccentricity metal-deficient halo stars. It has been suggested that these stars represent the signature of a rapid (if minor) collapse phase in the Galaxy's history. Employing velocity and integrals of motion phase-space projections of these stars, coupled with a series of N-body/smoothed particle hydrodynamic chemodynamical simulations, we suggest that an alternative mechanism for creating such stars may be the recent accretion of a polar orbit dwarf galaxy.

Fully printable transparent monolithic solid-state dye-sensitized solar cell with mesoscopic indium tin oxide counter electrode.

PubMed

Yang, Ying; Ri, Kwangho; Rong, Yaoguang; Liu, Linfeng; Liu, Tongfa; Hu, Min; Li, Xiong; Han, Hongwei

2014-09-07

We present a new transparent monolithic mesoscopic solid-state dye-sensitized solar cell based on trilamellar films of mesoscopic TiO2 nanocrystalline photoanode, a ZrO2 insulating layer and an indium tin oxide counter electrode (ITO-CE), which were screen-printed layer by layer on a single substrate. When the thickness of the ITO-CE was optimized to 2.1 μm, this very simple and fully printable solid-state DSSC with D102 dye and spiro-OMeTAD hole transport materials presents efficiencies of 1.73% when irradiated from the front side and 1.06% when irradiated from the rear side under a standard simulated sunlight condition (AM 1.5 Global, 100 mW cm(-2)). Higher parameters could be expected with a better transparent mesoscopic counter electrode and hole conductor for the printable monolithic mesoscopic solid-state DSSC.

[Monolithic column-gold composite substrate preparation and application to SERS detection of pigment].

PubMed

Xie, Yun-Fei; Li, Yan; Yu, Hui; Qian, He; Yao, Wei-Rong

2014-03-01

In the present study, we developed a novel SERS substrate with the porous monolith material combined with classic gold nanoparticles, and erythrosine as the research object, by adjusting the different experimental conditions for optimal SERS enhancements, including system pH and mixing time, and ultimately selected the optimum pH value 5.06 and mixing time 25 min. Compared with the traditional gold plastic substrate enhancement effect, the experimental conditions were applied to the monolith substrate SERS detection of dye erythrosine, different concentrations of samples were used for erythrosine SERS detection, and the detection limit reached 0.1 g x mL(-1). The method uses the payload of gold nanoparticles in mesoporous materials to effectively enhance the SERS signal. And this method has the advantages of simpleness and good stability, which provides a favorable theoretical basis for the rapid prohibited colorings screening.

Novel polymeric monolith materials with a β-cyclodextrin-graphene composite for the highly selective extraction of methyl jasmonate.

PubMed

Yu, Xinhong; Ling, Xu; Zou, Li; Chen, Zilin

2017-04-01

A novel polymeric monolith column with a  β-cyclodextrin-graphene composite was prepared for extraction of methyl jasmonate. A simple, sensitive, and effective polymeric monolith microextraction with high-performance liquid chromatography method has been presented for the determination. To carry out the best microextraction efficiency, several parameters such as sample flow rate, sample volume, and sample pH value were systematically optimized. In addition, the method validation showed a wide linear range of 5-2000 ng/mL, with a good linearity and low limits of detection for methyl jasmonate. The proposed method was successfully applied for the determination of methyl jasmonate in wintersweet flowers with recoveries of 90.67%. The result was confirmed by high-performance liquid chromatography with mass spectrometry. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Chromatographic performance of monolithic and particulate stationary phases. Hydrodynamics and adsorption capacity.

PubMed

Leinweber, Felix C; Tallarek, Ulrich

2003-07-18

Monolithic chromatographic support structures offer, as compared to the conventional particulate materials, a unique combination of high bed permeability, optimized solute transport to and from the active surface sites and a high loading capacity by the introduction of hierarchical order in the interconnected pore network and the possibility to independently manipulate the contributing sets of pores. While basic principles governing flow resistance, axial dispersion and adsorption capacity are remaining identical, and a similarity to particulate systems can be well recognized on that basis, a direct comparison of sphere geometry with monolithic structures is less obvious due, not least, to the complex shape of theskeleton domain. We present here a simple, widely applicable, phenomenological approach for treating single-phase incompressible flow through structures having a continuous, rigid solid phase. It relies on the determination of equivalent particle (sphere) dimensions which characterize the corresponding behaviour in a particulate, i.e. discontinuous bed. Equivalence is then obtained by dimensionless scaling of macroscopic fluid dynamical behaviour, hydraulic permeability and hydrodynamic dispersion in both types of materials, without needing a direct geometrical translation of their constituent units. Differences in adsorption capacity between particulate and monolithic stationary phases show that the silica-based monoliths with a bimodal pore size distribution provide, due to the high total porosity of the material of more than 90%, comparable maximum loading capacities with respect to random-close packings of completely porous spheres.

Process optimisation for anion exchange monolithic chromatography of 4.2kbp plasmid vaccine (pcDNA3F).

PubMed

Ongkudon, Clarence M; Danquah, Michael K

2010-10-15

Anion exchange monolithic chromatography is increasingly becoming a prominent tool for plasmid DNA purification but no generic protocol is available to purify all types of plasmid DNA. In this work, we established a simple framework and used it to specifically purify a plasmid DNA model from a clarified alkaline-lysed plasmid-containing cell lysate. The framework involved optimising ligand functionalisation temperature (30-80°C), mobile phase flow rate (0.1-1.8mL/min), monolith pore size (done by changing the porogen content in the polymerisation reaction by 50-80%), buffer pH (6-10), ionic strength of binding buffer (0.3-0.7M) and buffer gradient elution slope (1-10% buffer B/min). We concluded that preferential pcDNA3F adsorption and optimum resolution could be achieved within the tested conditions by loading the clarified cell lysate into 400nm pore size of monolith in 0.7M NaCl (pH 6) of binding buffer followed by increasing the NaCl concentration to 1.0M at 3%B/min. Copyright © 2010 Elsevier B.V. All rights reserved.

GaAs MOEMS Technology

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

SPAHN, OLGA B.; GROSSETETE, GRANT D.; CICH, MICHAEL J.

2003-03-01

Many MEMS-based components require optical monitoring techniques using optoelectronic devices for converting mechanical position information into useful electronic signals. While the constituent piece-parts of such hybrid opto-MEMS components can be separately optimized, the resulting component performance, size, ruggedness and cost are substantially compromised due to assembly and packaging limitations. GaAs MOEMS offers the possibility of monolithically integrating high-performance optoelectronics with simple mechanical structures built in very low-stress epitaxial layers with a resulting component performance determined only by GaAs microfabrication technology limitations. GaAs MOEMS implicitly integrates the capability for radiation-hardened optical communications into the MEMS sensor or actuator component, a vitalmore » step towards rugged integrated autonomous microsystems that sense, act, and communicate. This project establishes a new foundational technology that monolithically combines GaAs optoelectronics with simple mechanics. Critical process issues addressed include selectivity, electrochemical characteristics, and anisotropy of the release chemistry, and post-release drying and coating processes. Several types of devices incorporating this novel technology are demonstrated.« less

Direct mapping of local redox current density on a monolith electrode by laser scanning.

PubMed

Lee, Seung-Woo; Lopez, Jeffrey; Saraf, Ravi F

2013-09-15

An optical method of mapping local redox reaction over a monolith electrode using simple laser scanning is described. As the optical signal is linearly proportional to the maximum redox current that is measured concomitantly by voltammetry, the optical signal quantitatively maps the local redox current density distribution. The method is demonstrated on two types of reactions: (1) a reversible reaction where the redox moieties are ionic, and (2) an irreversible reaction on two different types of enzymes immobilized on the electrode where the reaction moieties are nonionic. To demonstrate the scanning capability, the local redox behavior on a "V-shaped" electrode is studied where the local length scale and, hence, the local current density, is nonuniform. The ability to measure the current density distribution by this method will pave the way for multianalyte analysis on a monolith electrode using a standard three-electrode configuration. The method is called Scanning Electrometer for Electrical Double-layer (SEED). Copyright © 2013 Elsevier B.V. All rights reserved.

The Influence of AN Interacting Vacuum Energy on the Gravitational Collapse of a Star Fluid

NASA Astrophysics Data System (ADS)

Campos, M.

2014-02-01

To explain the accelerated expansion of the universe, models with interacting dark components has been considered in the literature. Generally, the dark energy component is physically interpreted as the vacuum energy. However, at the other side of the same coin, the influence of the vacuum energy in the gravitational collapse is a topic of scientific interest. Based in a simple assumption on the collapsed rate of the matter fluid density that is altered by the inclusion of a vacuum energy component that interacts with the matter fluid, we study the final fate of the collapse process.

GaAs optoelectronic neuron arrays

NASA Technical Reports Server (NTRS)

Lin, Steven; Grot, Annette; Luo, Jiafu; Psaltis, Demetri

1993-01-01

A simple optoelectronic circuit integrated monolithically in GaAs to implement sigmoidal neuron responses is presented. The circuit integrates a light-emitting diode with one or two transistors and one or two photodetectors. The design considerations for building arrays with densities of up to 10,000/sq cm are discussed.

Gallium Nitride Monolithic Microwave Integrated Circuit Designs Using 0.25-micro m Qorvo Process

DTIC Science & Technology

2017-07-27

and sensor systems of interest to US Defense Department applications, particularly for next-generation radar systems. Broadband, efficient, high...A simple GaN high-electron-mobility-transistor (HEMT) TR single-pull double- throw (SPDT) switch consists of at least 2 series- and 2 shunt... simple TR switch that works well up to 6 GHz is shown in Figs. 4 (layout) and 5 (simulation). Complementary DC-bias voltages are applied at inputs A

Monolithic microwave integrated circuit devices for active array antennas

NASA Technical Reports Server (NTRS)

Mittra, R.

1984-01-01

Two different aspects of active antenna array design were investigated. The transition between monolithic microwave integrated circuits and rectangular waveguides was studied along with crosstalk in multiconductor transmission lines. The boundary value problem associated with a discontinuity in a microstrip line is formulated. This entailed, as a first step, the derivation of the propagating as well as evanescent modes of a microstrip line. The solution is derived to a simple discontinuity problem: change in width of the center strip. As for the multiconductor transmission line problem. A computer algorithm was developed for computing the crosstalk noise from the signal to the sense lines. The computation is based on the assumption that these lines are terminated in passive loads.

Synchronous delivery of felodipine and metoprolol tartrate using monolithic osmotic pump technology.

PubMed

Zhao, Shiqing; Yu, Fanglin; Liu, Nan; Di, Zhong; Yan, Kun; Liu, Yan; Li, Ying; Zhang, Hui; Yang, Yang; Yang, Zhenbo; Li, Zhiping; Mei, Xingguo

2016-11-01

The synchronous sustained-release of two drugs was desired urgently for patients needing combination therapy in long term. However, sophisticated technologies were used generally to realize the simultaneous delivery of two drugs especially those with different physico-chemical properties. The purpose of this study was to obtain the concurrent release of felodipine and metoprolol tartrate, two drugs with completely different solubilities, in a simple monolithic osmotic pump system (FMOP). Two types of blocking agents were used in monolithic osmotic pump tablets and the synchronous sustained-release of FMOP was acquired in vitro. The tablets were also administered to beagle dogs and the plasma levels of FMOP were determined by HPLC-MS/MS. The pharmacokinetic parameters were calculated using a non-compartmental model. Cmax of both felodipine and metoprolol from the osmotic pump tablets were lower, tmax and mean residence time of both felodipine and metoprolol from the osmotic pump tablets were longer significantly than those from immediate release tablets. These results verified prolonged release of felodipine and metoprolol tartrate from osmotic pump formulations. The similar absorption rate between felodipine and metoprolol in beagles was also obtained by this osmotic pump formulation. Therefore, it could be supposed that the accordant release of two drugs with completely different solubilities may be realized just by using monolithic osmotic pump technology.

Room-Temperature Low-Threshold Lasing from Monolithically Integrated Nanostructured Porous Silicon Hybrid Microcavities.

PubMed

Robbiano, Valentina; Paternò, Giuseppe M; La Mattina, Antonino A; Motti, Silvia G; Lanzani, Guglielmo; Scotognella, Francesco; Barillaro, Giuseppe

2018-05-22

Silicon photonics would strongly benefit from monolithically integrated low-threshold silicon-based laser operating at room temperature, representing today the main challenge toward low-cost and power-efficient electronic-photonic integrated circuits. Here we demonstrate low-threshold lasing from fully transparent nanostructured porous silicon (PSi) monolithic microcavities (MCs) infiltrated with a polyfluorene derivative, namely, poly(9,9-di- n-octylfluorenyl-2,7-diyl) (PFO). The PFO-infiltrated PSiMCs support single-mode blue lasing at the resonance wavelength of 466 nm, with a line width of ∼1.3 nm and lasing threshold of 5 nJ (15 μJ/cm 2 ), a value that is at the state of the art of PFO lasers. Furthermore, time-resolved photoluminescence shows a significant shortening (∼57%) of PFO emission lifetime in the PSiMCs, with respect to nonresonant PSi reference structures, confirming a dramatic variation of the radiative decay rate due to a Purcell effect. Our results, given also that blue lasing is a worst case for silicon photonics, are highly appealing for the development of low-cost, low-threshold silicon-based lasers with wavelengths tunable from visible to the near-infrared region by simple infiltration of suitable emitting polymers in monolithically integrated nanostructured PSiMCs.

Gallium Nitride (GaN) Monolithic Microwave Integrated Circuit (MMIC) Designs Submitted to Air Force Research Laboratory (AFRL) Sponsored Qorvo Fabrication

DTIC Science & Technology

2017-07-01

of interest to Department of Defense applications, particularly for next-generation radar systems. Broadband, efficient, high-power MMIC amplifiers...handling capability. Figures 1 and 2 show the layouts and simulations of a simple 1-stage 3- to 6-GHz Wilkinson coupler/combiner. A 2-stage broader band...from 4 to nearly 7 GHz for the 2-stage PA design. The simple , compact broadband feedback amplifier that serves as the first-stage driver for the 2

Free-standing graphene/vanadium oxide composite as binder-free electrode for asymmetrical supercapacitor.

PubMed

Deng, Lingjuan; Gao, Yihong; Ma, Zhanying; Fan, Guang

2017-11-01

Preparation of free-standing electrode materials with three-dimensional network architecture has emerged as an effective strategy for acquiring advanced portable and wearable power sources. Herein, graphene/vanadium oxide (GR/V 2 O 5 ) free-standing monolith composite has been prepared via a simple hydrothermal process. Flexible GR sheets acted as binder to connect the belt-like V 2 O 5 for assembling three-dimensional network architecture. The obtained GR/V 2 O 5 composite can be reshaped into GR/V 2 O 5 flexible film which exhibits more compact structure by ultrasonication and vacuum filtration. A high specific capacitance of 358Fg -1 for GR/V 2 O 5 monolith compared with that of GR/V 2 O 5 flexible film (272Fg -1 ) has been achieved in 0.5molL -1 K 2 SO 4 solution when used as binder free electrodes in three-electrode system. An asymmetrical supercapacitor has been assembled using GR/V 2 O 5 monolith as positive electrode and GR monolith as negative electrode, and it can be reversibly charged-discharged at a cell voltage of 1.7V in 0.5molL -1 K 2 SO 4 electrolyte. The asymmetrical capacitor can deliver an energy density of 26.22Whkg -1 at a power density of 425Wkg -1 , much higher than that of the symmetrical supercapacitor based on GR/V 2 O 5 monolith electrode. Moreover, the asymmetrical supercapacitor preserves 90% of its initial capacitance over 1000 cycles at a current density of 5Ag -1 . Copyright © 2017 Elsevier Inc. All rights reserved.

Effects of Cascaded Voltage Collapse and Protection of Many Induction Machine Loads upon Load Characteristics Viewed from Bulk Transmission System

NASA Astrophysics Data System (ADS)

Kumano, Teruhisa

As known well, two of the fundamental processes which give rise to voltage collapse in power systems are the on load tap changers of transformers and dynamic characteristics of loads such as induction machines. It has been well established that, comparing among these two, the former makes slower collapse while the latter makes faster. However, in realistic situations, the load level of each induction machine is not uniform and it is well expected that only a part of loads collapses first, followed by collapse process of each load which did not go into instability during the preceding collapses. In such situations the over all equivalent collapse behavior viewed from bulk transmission level becomes somewhat different from the simple collapse driven by one aggregated induction machine. This paper studies the process of cascaded voltage collapse among many induction machines by time simulation, where load distribution on a feeder line is modeled by several hundreds of induction machines and static impedance loads. It is shown that in some cases voltage collapse really cascades among induction machines, where the macroscopic load dynamics viewed from upper voltage level makes slower collapse than expected by the aggregated load model. Also shown is the effects of machine protection of induction machines, which also makes slower collapse.

Preparation and characterizations of activated carbon monolith from rubber wood and its effect on supercapacitor performances

NASA Astrophysics Data System (ADS)

Taer, E.; Taslim, R.; Deraman, M.

2016-02-01

Preparation of activated carbon monolith (ACM) from rubber wood was investigated. Two kind of preparation method were carried out by pre-carbonized of rubber wood saw dust and rubber wood material as it is naturally. The samples were prepared with pelletizing method and small cutting of rubber wood in cross sectional method. Both of samples were characterized by physical and electrochemical technique. The physical properties such as morphology and porosity were investigated. The electrochemical properties of both samples such as equivalent series resistances (ESR) and specific capacitances were also compared. In conclusion, this study showed that both of different preparation method would propose a simple method of ACM electrode preparation technique for supercapacitor applications.

Synthesis of silica aerogel monoliths with controlled specific surface areas and pore sizes

NASA Astrophysics Data System (ADS)

Gao, Bingying; Lu, Shaoxiang; Kalulu, Mulenga; Oderinde, Olayinka; Ren, Lili

2017-07-01

To replace traditional preparation methods of silica aerogels, a small-molecule 1,2-epoxypropane (PO) has been introduced into the preparation process instead of using ammonia as the cross-linking agent, thus generating a lightweight, high porosity, and large surface area silica aerogel monolithic. We put forward a simple solution route for the chemical synthesis of silica aerogels, which was characterized by scanning electron microscopy (SEM), TEM, XRD, FTIR, thermogravimetric analysis (TGA) and the Brunauer-Emmett-Teller (BET) method In this paper, the effect of the amount of PO on the microstructure of silica aerogels is discussed. The BET surface areas and pore sizes of the resulting silica aerogels can be freely adjusted by changing the amount of PO, which will be helpful in promoting the development of silica aerogels to fabricate other porous materials with similar requirements. We also adopted a new organic solvent sublimation drying (OSSD) method to replace traditional expensive and dangerous drying methods such as critical point drying and freeze drying. This simple approach is easy to operate and has good repeatability, which will further facilitate actual applications of silica aerogels.

Nitrogen-doped porous carbon monoliths from polyacrylonitrile (PAN) and carbon nanotubes as electrodes for supercapacitors

PubMed Central

Wang, Yanqing; Fugetsu, Bunshi; Wang, Zhipeng; Gong, Wei; Sakata, Ichiro; Morimoto, Shingo; Hashimoto, Yoshio; Endo, Morinobu; Dresselhaus, Mildred; Terrones, Mauricio

2017-01-01

Nitrogen-doped porous activated carbon monoliths (NDP-ACMs) have long been the most desirable materials for supercapacitors. Unique to the conventional template based Lewis acid/base activation methods, herein, we report on a simple yet practicable novel approach to production of the three-dimensional NDP-ACMs (3D-NDP-ACMs). Polyacrylonitrile (PAN) contained carbon nanotubes (CNTs), being pre-dispersed into a tubular level of dispersions, were used as the starting material and the 3D-NDP-ACMs were obtained via a template-free process. First, a continuous mesoporous PAN/CNT based 3D monolith was established by using a template-free temperature-induced phase separation (TTPS). Second, a nitrogen-doped 3D-ACM with a surface area of 613.8 m2/g and a pore volume 0.366 cm3/g was obtained. A typical supercapacitor with our 3D-NDP-ACMs as the functioning electrodes gave a specific capacitance stabilized at 216 F/g even after 3000 cycles, demonstrating the advantageous performance of the PAN/CNT based 3D-NDP-ACMs. PMID:28074847

On-chip sample pretreatment using a porous polymer monolithic column for solid-phase microextraction and chemiluminescence determination of catechins in green tea.

PubMed

Lin, Ling; Chen, Hui; Wei, Huibin; Wang, Feng; Lin, Jin-Ming

2011-10-21

A porous polymer monolithic column for solid-phase microextraction and chemiluminescence detection was integrated into a simple microfluidic chip for the extraction and determination of catechins in green tea. The porous polymer was prepared by poly(glycidyl methacrylate-co-ethylene dimethacrylate) and modified with ethylenediamine. Catechins can be concentrated in the porous polymer monolithic column and react with potassium permanganate to give chemiluminescence. The microfluidic chip is reusable with high sensitivity and very low reagent consumption. The on-line preconcentration and detection can be realized without an elution step. The enrichment factor was calculated to be about 20 for catechins. The relative chemiluminescence intensity increased linearly with concentration of catechin from 5.0 × 10(-9) to 1.0 × 10(-6) M and the limit of detection was 1.0 × 10(-9) M. The proposed method was applied to determine catechin in green tea. The recoveries are from 90% to 110% which benefits the actual application for green tea samples.

Nitrogen-doped porous carbon monoliths from polyacrylonitrile (PAN) and carbon nanotubes as electrodes for supercapacitors

NASA Astrophysics Data System (ADS)

Wang, Yanqing; Fugetsu, Bunshi; Wang, Zhipeng; Gong, Wei; Sakata, Ichiro; Morimoto, Shingo; Hashimoto, Yoshio; Endo, Morinobu; Dresselhaus, Mildred; Terrones, Mauricio

2017-01-01

Nitrogen-doped porous activated carbon monoliths (NDP-ACMs) have long been the most desirable materials for supercapacitors. Unique to the conventional template based Lewis acid/base activation methods, herein, we report on a simple yet practicable novel approach to production of the three-dimensional NDP-ACMs (3D-NDP-ACMs). Polyacrylonitrile (PAN) contained carbon nanotubes (CNTs), being pre-dispersed into a tubular level of dispersions, were used as the starting material and the 3D-NDP-ACMs were obtained via a template-free process. First, a continuous mesoporous PAN/CNT based 3D monolith was established by using a template-free temperature-induced phase separation (TTPS). Second, a nitrogen-doped 3D-ACM with a surface area of 613.8 m2/g and a pore volume 0.366 cm3/g was obtained. A typical supercapacitor with our 3D-NDP-ACMs as the functioning electrodes gave a specific capacitance stabilized at 216 F/g even after 3000 cycles, demonstrating the advantageous performance of the PAN/CNT based 3D-NDP-ACMs.

Ultralight metal foams

NASA Astrophysics Data System (ADS)

Jiang, Bin; He, Chunnian; Zhao, Naiqin; Nash, Philip; Shi, Chunsheng; Wang, Zejun

2015-09-01

Ultralight (<10 mg/cm3) cellular materials are desirable for thermal insulation; battery electrodes; catalyst supports; and acoustic, vibration, or shock energy damping. However, most of these ultralight materials, especially ultralight metal foams, are fabricated using either expensive materials or complicated procedures, which greatly limit their large-scale production and practical applications. Here we report a simple and versatile method to obtain ultralight monolithic metal foams. These materials are fabricated with a low-cost polymeric template and the method is based on the traditional silver mirror reaction and electroless plating. We have produced ultralight monolithic metal foams, such as silver, nickel, cobalt, and copper via this method. The resultant ultralight monolithic metal foams have remarkably low densities down to 7.4 mg/cm3 or 99.9% porosity. The metal foams have a long flat stress-train curve in compression tests and the densification strain ɛD of the Ni/Ag foam with a porosity of 99.8% can reach 82%. The plateau stress σpl was measured and found to be in agreement with the value predicted by the cellular solids theory.

Ultralight metal foams.

PubMed

Jiang, Bin; He, Chunnian; Zhao, Naiqin; Nash, Philip; Shi, Chunsheng; Wang, Zejun

2015-09-08

Ultralight (<10 mg/cm3) cellular materials are desirable for thermal insulation; battery electrodes; catalyst supports; and acoustic, vibration, or shock energy damping. However, most of these ultralight materials, especially ultralight metal foams, are fabricated using either expensive materials or complicated procedures, which greatly limit their large-scale production and practical applications. Here we report a simple and versatile method to obtain ultralight monolithic metal foams. These materials are fabricated with a low-cost polymeric template and the method is based on the traditional silver mirror reaction and electroless plating. We have produced ultralight monolithic metal foams, such as silver, nickel, cobalt, and copper via this method. The resultant ultralight monolithic metal foams have remarkably low densities down to 7.4 mg/cm3 or 99.9% porosity. The metal foams have a long flat stress-train curve in compression tests and the densification strain εD of the Ni/Ag foam with a porosity of 99.8% can reach 82%. The plateau stress σpl was measured and found to be in agreement with the value predicted by the cellular solids theory.

Nitrogen-doped porous carbon monoliths from polyacrylonitrile (PAN) and carbon nanotubes as electrodes for supercapacitors.

PubMed

Wang, Yanqing; Fugetsu, Bunshi; Wang, Zhipeng; Gong, Wei; Sakata, Ichiro; Morimoto, Shingo; Hashimoto, Yoshio; Endo, Morinobu; Dresselhaus, Mildred; Terrones, Mauricio

2017-01-11

Nitrogen-doped porous activated carbon monoliths (NDP-ACMs) have long been the most desirable materials for supercapacitors. Unique to the conventional template based Lewis acid/base activation methods, herein, we report on a simple yet practicable novel approach to production of the three-dimensional NDP-ACMs (3D-NDP-ACMs). Polyacrylonitrile (PAN) contained carbon nanotubes (CNTs), being pre-dispersed into a tubular level of dispersions, were used as the starting material and the 3D-NDP-ACMs were obtained via a template-free process. First, a continuous mesoporous PAN/CNT based 3D monolith was established by using a template-free temperature-induced phase separation (TTPS). Second, a nitrogen-doped 3D-ACM with a surface area of 613.8 m 2 /g and a pore volume 0.366 cm 3 /g was obtained. A typical supercapacitor with our 3D-NDP-ACMs as the functioning electrodes gave a specific capacitance stabilized at 216 F/g even after 3000 cycles, demonstrating the advantageous performance of the PAN/CNT based 3D-NDP-ACMs.

Preparation of 2,4-dichlorophenoxyacetic acid imprinted organic-inorganic hybrid monolithic column and application to selective solid-phase microextraction.

PubMed

Liu, Xiaofang; Zhu, Quanfei; Chen, Huaixia; Zhou, Liuzi; Dang, Xueping; Huang, Jianlin

2014-03-01

An organic-inorganic hybrid molecular imprinting monolith (HMIM) has been prepared, characterized and applied for the determination of 2,4-dichlorophenoxyacetic acid (2,4-D) in rice with high-performance liquid chromatography-photodiodes array detector (HPLC-PAD). By optimizing the polymerization conditions, such as the volume ratio of the inorganic alcoholysate and organic part, the 2,4-D-HMIM was synthesized in a micro pipette tip using acrylamide as the functional monomer, ethylene dimethacrylate as the cross-linker and methanol as the porogenic solvent. The morphology of the monolith was studied by scanning electronmicroscopy and Fourier transform infrared spectra. The imprinted factor of the monolith for 2,4-D reached 3.29. A simple, rapid and sensitive method for the determination of 2,4-D in rice using the HMIM microextraction combined with high-performance liquid chromatography-photodiodes array detector was developed. Some parameters affecting the sample pretreatment were investigated, including the type and volume of eluent, the flow rate and volume of sample solution. The assay exhibited a linear dynamic range of 167-4167μg/kg with the correlation coefficient above 0.9972. The detection limit (at S/N=3) was 50μg/kg. The proposed method was successfully applied for the selective determination of 2,4-D in rice. Copyright © 2014 Elsevier B.V. All rights reserved.

Warming of Monolithic Structures in Winter

NASA Astrophysics Data System (ADS)

Pikus, G. A.; Lebed, A. R.

2017-11-01

The present work attempts to develop a mathematical model for calculating the heat transfer coefficient of the fence of monolithic structures erected in winter. The urgency and, at the same time, the practical significance of the research lies in the fact that to date no simple, effective tool has been developed to ensure the elimination of the unfavorable thermally stressed state of a structure’s concrete from maximum equalization of temperatures across its cross-section. The main problem for concrete is a high temperature which leads to a sharp decrease in the quality of erected structures due to developing cracks. This paper based on the well-known Newton’s law and its differential equation demonstrates the formula of concrete cooling and the analysis of its proportionality coefficient. Based on the literature analysis, it is established that the proportionality coefficient is determined by the thermophysical properties of concrete, the size and shape of the structure, and the intensity of its heat exchange with the surrounding medium. A limitation was used on the temperature gradient over the section of the monolithic structure to derive a formula for calculating the reduced heat transfer coefficient of a concrete fence. All mathematical calculations are given for cooling monolithic constructions in the form of plates. At the end of the work an example is given for the calculation of the required reduced heat transfer coefficient for the fence ensuring compliance with the permissible concrete temperature gradient.

Timescales of isotropic and anisotropic cluster collapse

NASA Astrophysics Data System (ADS)

Bartelmann, M.; Ehlers, J.; Schneider, P.

1993-12-01

From a simple estimate for the formation time of galaxy clusters, Richstone et al. have recently concluded that the evidence for non-virialized structures in a large fraction of observed clusters points towards a high value for the cosmological density parameter Omega0. This conclusion was based on a study of the spherical collapse of density perturbations, assumed to follow a Gaussian probability distribution. In this paper, we extend their treatment in several respects: first, we argue that the collapse does not start from a comoving motion of the perturbation, but that the continuity equation requires an initial velocity perturbation directly related to the density perturbation. This requirement modifies the initial condition for the evolution equation and has the effect that the collapse proceeds faster than in the case where the initial velocity perturbation is set to zero; the timescale is reduced by a factor of up to approximately equal 0.5. Our results thus strengthens the conclusion of Richstone et al. for a high Omega0. In addition, we study the collapse of density fluctuations in the frame of the Zel'dovich approximation, using as starting condition the analytically known probability distribution of the eigenvalues of the deformation tensor, which depends only on the (Gaussian) width of the perturbation spectrum. Finally, we consider the anisotropic collapse of density perturbations dynamically, again with initial conditions drawn from the probability distribution of the deformation tensor. We find that in both cases of anisotropic collapse, in the Zel'dovich approximation and in the dynamical calculations, the resulting distribution of collapse times agrees remarkably well with the results from spherical collapse. We discuss this agreement and conclude that it is mainly due to the properties of the probability distribution for the eigenvalues of the Zel'dovich deformation tensor. Hence, the conclusions of Richstone et al. on the value of Omega0 can be verified and strengthened, even if a more general approach to the collapse of density perturbations is employed. A simple analytic formula for the cluster redshift distribution in an Einstein-deSitter universe is derived.

Fast or Frugal, but Not Both: Decision Heuristics under Time Pressure

ERIC Educational Resources Information Center

Bobadilla-Suarez, Sebastian; Love, Bradley C.

2018-01-01

Heuristics are simple, yet effective, strategies that people use to make decisions. Because heuristics do not require all available information, they are thought to be easy to implement and to not tax limited cognitive resources, which has led heuristics to be characterized as fast-and-frugal. We question this monolithic conception of heuristics…

Monolithic integration of SOI waveguide photodetectors and transimpedance amplifiers

NASA Astrophysics Data System (ADS)

Li, Shuxia; Tarr, N. Garry; Ye, Winnie N.

2018-02-01

In the absence of commercial foundry technologies offering silicon-on-insulator (SOI) photonics combined with Complementary Metal Oxide Semiconductor (CMOS) transistors, monolithic integration of conventional electronics with SOI photonics is difficult. Here we explore the implementation of lateral bipolar junction transistors (LBJTs) and Junction Field Effect Transistors (JFETs) in a commercial SOI photonics technology lacking MOS devices but offering a variety of n- and p-type ion implants intended to provide waveguide modulators and photodetectors. The fabrication makes use of the commercial Institute of Microelectronics (IME) SOI photonics technology. Based on knowledge of device doping and geometry, simple compact LBJT and JFET device models are developed. These models are then used to design basic transimpedance amplifiers integrated with optical waveguides. The devices' experimental current-voltage characteristics results are reported.

Lifetime of Bubble Rafts: Cooperativity and Avalanches

NASA Astrophysics Data System (ADS)

Ritacco, Hernán; Kiefer, Flavien; Langevin, Dominique

2007-06-01

We have studied the collapse of pseudo-bi-dimensional foams. These foams are made of uniformly sized soap bubbles packed in an hexagonal lattice sitting at the top of a liquid surface. The collapse process follows the sequence: (1) rupture of a first bubble, driven by thermal fluctuations and (2) a cascade of bursting bubbles. We present a simple numerical model which captures the main characteristics of the dynamics of foam collapse. We show that in a certain range of viscosities of the foaming solutions, the size distribution of the avalanches follows power laws as in self-organized criticality processes.

Lifetime of bubble rafts: cooperativity and avalanches.

PubMed

Ritacco, Hernán; Kiefer, Flavien; Langevin, Dominique

2007-06-15

We have studied the collapse of pseudo-bi-dimensional foams. These foams are made of uniformly sized soap bubbles packed in an hexagonal lattice sitting at the top of a liquid surface. The collapse process follows the sequence: (1) rupture of a first bubble, driven by thermal fluctuations and (2) a cascade of bursting bubbles. We present a simple numerical model which captures the main characteristics of the dynamics of foam collapse. We show that in a certain range of viscosities of the foaming solutions, the size distribution of the avalanches follows power laws as in self-organized criticality processes.

The role of fluid viscosity in an immersed granular collapse

NASA Astrophysics Data System (ADS)

Yang, Geng Chao; Kwok, Chung Yee; Sobral, Yuri Dumaresq

2017-06-01

Instabilities of immersed slopes and cliffs can lead to catastrophic events that involve a sudden release of huge soil mass. The scaled deposit height and runout distance are found to follow simple power laws when a granular column collapses on a horizontal plane. However, if the granular column is submerged in a fluid, the mobility of the granular collapse due to high inertia effects will be reduced by fluid-particle interactions. In this study, the effects of fluid viscosity on granular collapse is investigated qualitatively by adopting a numerical approach based on the coupled lattice Boltzmann method (LBM) and discrete element method (DEM). It is found that the granular collapse can be dramatically slowed down due to the presence of viscous fluids. For the considered granular configuration, when the fluid viscosity increases. the runout distance decreases and the final deposition shows a larger deposit angle.

The collapse of a cavitation bubble in a corner

NASA Astrophysics Data System (ADS)

Peters, Ivo; Tagawa, Yoshiyuki

2017-11-01

The collapse of cavitation bubbles is influenced by the surrounding geometry. A classic example is the collapse of a bubble near a solid wall, where a fast jet is created towards the wall. The addition of a second wall creates a non-axisymmetric flow field, which influences the displacement and jet formation during the collapse of a bubble. In this experimental study we generate mm-sized vapor bubbles using a focused pulsed laser, giving us full control over the position of the bubble. The corner geometry is formed by two glass slides. High-speed imaging reveals the directional motion of the bubble during the collapse. We find that the bubble displacement cannot be fully described by a simple superposition of the bubble dynamics of the two walls individually. Comparison of our experimental results to a model based on potential flow shows a good agreement for the direction of displacement.

Development of a bi-functional silica monolith for electro-osmotic pumping and DNA clean-up/extraction using gel-supported reagents in a microfluidic device.

PubMed

Oakley, Jennifer A; Shaw, Kirsty J; Docker, Peter T; Dyer, Charlotte E; Greenman, John; Greenway, Gillian M; Haswell, Stephen J

2009-06-07

A silica monolith used to support both electro-osmotic pumping (EOP) and the extraction/elution of DNA coupled with gel-supported reagents is described. The benefits of the combined EOP extraction/elution system were illustrated by combining DNA extraction and gene amplification using the polymerase chain reaction (PCR) process. All the reagents necessary for both processes were supported within pre-loaded gels that allow the reagents to be stored at 4 degrees C for up to four weeks in the microfluidic device. When carrying out an analysis the crude sample only needed to be hydrodynamically introduced into the device which was connected to an external computer controlled power supply via platinum wire electrodes. DNA was extracted with 65% efficiency after loading lysed cells onto a silica monolith. Ethanol contained within an agarose gel matrix was then used to wash unwanted debris away from the sample by EOP (100 V cm(-1) for 5 min). The retained DNA was subsequently eluted from the monolith by water contained in a second agarose gel, again by EOP using an electric field of 100 V cm(-1) for 5 min, and transferred into the PCR reagent containing gel. The eluted DNA in solution was successfully amplified by PCR, confirming that the concept of a complete self-contained microfluidic device could be realised for DNA sample clean up and amplification, using a simple pumping and on-chip reagent storage methodology.

Monolithic Cylindrical Fused Silica Resonators with High Q Factors

PubMed Central

Pan, Yao; Wang, Dongya; Wang, Yanyan; Liu, Jianping; Wu, Suyong; Qu, Tianliang; Yang, Kaiyong; Luo, Hui

2016-01-01

The cylindrical resonator gyroscope (CRG) is a typical Coriolis vibratory gyroscope whose performance is determined by the Q factor and frequency mismatch of the cylindrical resonator. Enhancing the Q factor is crucial for improving the rate sensitivity and noise performance of the CRG. In this paper, for the first time, a monolithic cylindrical fused silica resonator with a Q factor approaching 8 × 105 (ring-down time over 1 min) is reported. The resonator is made of fused silica with low internal friction and high isotropy, with a diameter of 25 mm and a center frequency of 3974.35 Hz. The structure of the resonator is first briefly introduced, and then the experimental non-contact characterization method is presented. In addition, the post-fabrication experimental procedure of Q factor improvement, including chemical and thermal treatment, is demonstrated. The Q factor improvement by both treatments is compared and the primary loss mechanism is analyzed. To the best of our knowledge, the work presented in this paper represents the highest reported Q factor for a cylindrical resonator. The proposed monolithic cylindrical fused silica resonator may enable high performance inertial sensing with standard manufacturing process and simple post-fabrication treatment. PMID:27483263

Supply based on demand dynamical model

NASA Astrophysics Data System (ADS)

Levi, Asaf; Sabuco, Juan; Sanjuán, Miguel A. F.

2018-04-01

We propose and numerically analyze a simple dynamical model that describes the firm behaviors under uncertainty of demand. Iterating this simple model and varying some parameter values, we observe a wide variety of market dynamics such as equilibria, periodic, and chaotic behaviors. Interestingly, the model is also able to reproduce market collapses.

Discriminating the effects of collapse models from environmental diffusion with levitated nanospheres

NASA Astrophysics Data System (ADS)

Li, Jie; Zippilli, Stefano; Zhang, Jing; Vitali, David

2016-05-01

Collapse models postulate the existence of intrinsic noise which modifies quantum mechanics and is responsible for the emergence of macroscopic classicality. Assessing the validity of these models is extremely challenging because it is nontrivial to discriminate unambiguously their presence in experiments where other hardly controllable sources of noise compete to the overall decoherence. Here we provide a simple procedure that is able to probe the hypothetical presence of the collapse noise with a levitated nanosphere in a Fabry-Pérot cavity. We show that the stationary state of the system is particularly sensitive, under specific experimental conditions, to the interplay between the trapping frequency, the cavity size, and the momentum diffusion induced by the collapse models, allowing one to detect them even in the presence of standard environmental noises.

Lightweight, Superelastic, and Mechanically Flexible Graphene/Polyimide Nanocomposite Foam for Strain Sensor Application.

PubMed

Qin, Yuyang; Peng, Qingyu; Ding, Yujie; Lin, Zaishan; Wang, Chunhui; Li, Ying; Xu, Fan; Li, Jianjun; Yuan, Ye; He, Xiaodong; Li, Yibin

2015-09-22

The creation of superelastic, flexible three-dimensional (3D) graphene-based architectures is still a great challenge due to structure collapse or significant plastic deformation. Herein, we report a facile approach of transforming the mechanically fragile reduced graphene oxide (rGO) aerogel into superflexible 3D architectures by introducing water-soluble polyimide (PI). The rGO/PI nanocomposites are fabricated using strategies of freeze casting and thermal annealing. The resulting monoliths exhibit low density, excellent flexibility, superelasticity with high recovery rate, and extraordinary reversible compressibility. The synergistic effect between rGO and PI endows the elastomer with desirable electrical conductivity, remarkable compression sensitivity, and excellent durable stability. The rGO/PI nanocomposites show potential applications in multifunctional strain sensors under the deformations of compression, bending, stretching, and torsion.

Use of Collapsible Box Trainer as a Module for Resident Education

PubMed Central

Caban, Angel M.; Guido, Christopher; Silver, Michele; Rossidis, George; Sarosi, George

2013-01-01

Background and Objectives: We sought to determine whether training with a simple collapsible mobile box trainer leads to improved performance of fundamental laparoscopic skills (FLSs) during a 6-month interval versus validated laparoscopic box trainers and virtual-reality trainers, only accessible at a simulation training center. Methods: With institutional review board approval, 20 first- and second-year general surgery residents were randomized to scheduled training sessions in a surgical simulation laboratory or training in the use of a portable, collapsible Train Anywhere Skill Kit (TASKit) (Ethicon Endo-Surgery Cincinnati, OH, USA) trainer. Training was geared toward the FLS set for a skill assessment examination at a 6-month interval. Results: The residents who trained with the TASKit performed the peg-transfer, pattern-cut exercise, Endoloop, and intracorporeal knot-tying FLS tasks statistically more efficiently during their 6-month assessment versus their initial evaluation as compared with the group randomized to the simulation laboratory training. Conclusions: Using a simple collapsible mobile box trainer such as the TASKit can be a cost-effective method of training and preparing residents for FLS tasks considering the current cost associated with virtual and high-definition surgical trainers. This mode of surgical training allows residents to practice in their own time by removing barriers associated with simulation centers. PMID:24018083

Cavity-enhanced frequency doubling from 795nm to 397.5nm ultra-violet coherent radiation with PPKTP crystals in the low pump power regime.

PubMed

Wen, Xin; Han, Yashuai; Bai, Jiandong; He, Jun; Wang, Yanhua; Yang, Baodong; Wang, Junmin

2014-12-29

We demonstrate a simple, compact and cost-efficient diode laser pumped frequency doubling system at 795 nm in the low power regime. In two configurations, a bow-tie four-mirror ring enhancement cavity with a PPKTP crystal inside and a semi-monolithic PPKTP enhancement cavity, we obtain 397.5nm ultra-violet coherent radiation of 35mW and 47mW respectively with a mode-matched fundamental power of about 110mW, corresponding to a conversion efficiency of 32% and 41%. The low loss semi-monolithic cavity leads to the better results. The constructed ultra-violet coherent radiation has good power stability and beam quality, and the system has huge potential in quantum optics and cold atom physics.

A simple mathematical model of society collapse applied to Easter Island

NASA Astrophysics Data System (ADS)

Bologna, M.; Flores, J. C.

2008-02-01

In this paper we consider a mathematical model for the evolution and collapse of the Easter Island society. Based on historical reports, the available primary resources consisted almost exclusively in the trees, then we describe the inhabitants and the resources as an isolated dynamical system. A mathematical, and numerical, analysis about the Easter Island community collapse is performed. In particular, we analyze the critical values of the fundamental parameters and a demographic curve is presented. The technological parameter, quantifying the exploitation of the resources, is calculated and applied to the case of another extinguished civilization (Copán Maya) confirming the consistency of the adopted model.

Transition to chaos of a vertical collapsible tube conveying air flow

NASA Astrophysics Data System (ADS)

Castillo Flores, F.; Cros, A.

2009-05-01

"Sky dancers", the large collapsible tubes used as advertising, are studied in this work through a simple experimental device. Our study is devoted to the nonlinear dynamics of this system and to its transition to chaos. Firstly, we have shown that after a collapse occurs, the air fills the tube at a different speed rate from the flow velocity. Secondly, the temporal intermittency is studied as the flow rate is increased. A statistical analysis shows that the chaotic times maintain roughly the same value by increasing air speed. On the other hand, laminar times become shorter, until the system reaches a completely chaotic state.

Enhancing the noise performance of monolithic microwave integrated circuit-based low noise amplifiers through the use of a discrete preamplifying transistor

NASA Astrophysics Data System (ADS)

McCulloch, Mark A.; Melhuish, Simon J.; Piccirillo, Lucio

2015-01-01

An approach to enhancing the noise performance of an InP monolithic microwave integrated circuit (MMIC)-based low noise amplifiers (LNA) through the use of a discrete 100-nm gate length InP high electron mobility transistor is outlined. This LNA, known as a transistor in front of MMIC (T + MMIC) LNA, possesses a gain in excess of 40 dB and an average noise temperature of 9.4 K across the band 27 to 33 GHz at a physical temperature of 8 K. This compares favorably with 14.5 K for an LNA containing an equivalent MMIC. A simple advanced design system model offering further insights into the operation of the LNA is also presented and the LNA is compared with the current state-of-the-art Planck LFI LNAs.

Probabilistic hindcasts and projections of the coupled climate, carbon cycle and Atlantic meridional overturning circulation system: a Bayesian fusion of century-scale observations with a simple model

NASA Astrophysics Data System (ADS)

Urban, Nathan M.; Keller, Klaus

2010-10-01

How has the Atlantic Meridional Overturning Circulation (AMOC) varied over the past centuries and what is the risk of an anthropogenic AMOC collapse? We report probabilistic projections of the future climate which improve on previous AMOC projection studies by (i) greatly expanding the considered observational constraints and (ii) carefully sampling the tail areas of the parameter probability distribution function (pdf). We use a Bayesian inversion to constrain a simple model of the coupled climate, carbon cycle and AMOC systems using observations to derive multicentury hindcasts and projections. Our hindcasts show considerable skill in representing the observational constraints. We show that robust AMOC risk estimates can require carefully sampling the parameter pdfs. We find a low probability of experiencing an AMOC collapse within the 21st century for a business-as-usual emissions scenario. The probability of experiencing an AMOC collapse within two centuries is 1/10. The probability of crossing a forcing threshold and triggering a future AMOC collapse (by 2300) is approximately 1/30 in the 21st century and over 1/3 in the 22nd. Given the simplicity of the model structure and uncertainty in the forcing assumptions, our analysis should be considered a proof of concept and the quantitative conclusions subject to severe caveats.

Polymer monolithic capillary microextraction combined on-line with inductively coupled plasma MS for the determination of trace rare earth elements in biological samples.

PubMed

Zhang, Lin; Chen, Beibei; He, Man; Hu, Bin

2013-07-01

A rapid and sensitive method based on polymer monolithic capillary microextraction combined on-line with microconcentric nebulization inductively coupled plasma MS has been developed for the determination of trace/ultratrace rare earth elements in biological samples. For this purpose, the iminodiacetic acid modified poly(glycidyl methacrylate-trimethylolpropane trimethacrylate) monolithic capillary was prepared and characterized by SEM and FTIR spectroscopy. Factors affecting the extraction efficiency, such as sample pH, sample flow rate, sample/eluent volume, and coexisting ions were investigated in detail. Under the optimal conditions, the LODs for rare earth elements were in the range of 0.08 (Er) to 0.97 ng/L (Nd) with a sampling frequency of 8.5 h(-1), and the RSDs were between 1.5% (Sm) and 7.4% (Nd) (c = 20 ng/L, n = 7). The proposed method was successfully applied to the analysis of trace/ultratrace rare earth elements in human urine and serum samples, and the recoveries for the spiked samples were in the range of 82-105%. The developed method was simple, rapid, sensitive, and favorable for the analysis of trace/ultratrace rare earth elements in biological samples with limited sample volume. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

[Rapid determination of trace iodate using monolithic column ion-pair chromatography coupled with direct conductivity detection].

PubMed

Liu, Yuzhen; Yu, Hong; Li, Siwen

2011-10-01

A method was developed on a monolithic column for the fast determination of trace iodate (IO(3)- ) by ion-pair chromatography with direct conductivity detection. The analytes were separated using a mobile phase of tetrabutylammonium hydroxide (TBA)-phthalic acid-acetonitrile on a reversed-phase silica-based monolithic column. The effects of eluent, flow rate and column temperature on the retention of iodate were investigated. The optimized chromatographic conditions for the determination of the anion were as follows: 0. 25 mmol/L TBA-0. 18 mmol/L phthalic acid-3% acetonitrile (pH 5.5) as mobile phase, a flow rate of 4.0 mL/min and a column temperature of 30 degrees C. Under the optimal conditions, retention time of iodate was less than 0. 5 min and the baseline separation of iodate was achieved without any interference by other anions (Cl-, NO , SO4(2)-, I- ). The detection limit (S/N= 3) was 0.36 mg/L for IO(3)- . Relative standard deviation (RSD, n = 5) of chromatographic peak area and retention time were 0. 35% and 0. 28%, respectively. The proposed method was applied to the determination of trace iodate in iodized medicine. The spiked recovery of iodate was 96. 4%. The method is rapid, simple, accurate, reliable, and practical.

Determination of benzimidazole anthelmintics in milk and honey by monolithic fiber-based solid-phase microextraction combined with high-performance liquid chromatography-diode array detection.

PubMed

Zhang, Yong; Huang, Xiaojia; Yuan, Dongxing

2015-01-01

A porous poly(methacrylic acid-co-ethylene dimethacrylate) monolithic fiber (MEMF) for solid-phase microextraction (SPME) of five benzimidazole anthelmintics was prepared by in-situ polymerization. The effect of polymerization conditions on SPME of the target analytes was studied thoroughly. The physicochemical properties of the monolith were characterized by infrared spectroscopy, elemental analysis, scanning electron microscopy, and mercury intrusion porosimetry. Several conditions affecting the extraction efficiency were investigated and, under the optimized conditions, a simple and sensitive method for the determination of trace benzimidazoles residues in milk and honey was established by coupling MEMF-SPME with high-performance liquid chromatography-diode array detection (MEMF-SPME-HPLC-DAD). Under the optimum experimental conditions, the limits of detection (S/N = 3) of the method were 0.11-0.30 μg L(-1) for milk and 0.086-0.28 μg L(-1) for honey. Evaluation of intra-day and inter-day precision showed reproducibility was satisfactory-relative standard deviations (RSD) for both were <10 %. Finally, the method was successfully used for determination of benzimidazole residues in milk and honey. Recoveries obtained for determination of benzimidazole anthelmintics in spiked samples ranged from 72.3 to 121 %, with RSD always <11 %.

Reversible collapse of insoluble monolayers: new insights on the influence of the anisotropic line tension of the domain.

PubMed

González-Delgado, Antonio M; Pérez-Morales, Marta; Giner-Casares, Juan J; Muñoz, Eulogia; Martín-Romero, María T; Camacho, Luis

2009-10-08

In this paper, we study the collapse of a mixed insoluble monolayer formed by a cationic matrix, dioctadecyl-dimethylammonium bromide (DOMA), and a tetra-anionic porphyrin, tetrakis(4-sulfonatophenyl)porphyrin (TSPP), in a molar ratio TSPP/DOMA = 1:4. During the collapse of this system, we visualized the formation of circular domains consisting exclusively of trilayer, although the domains coalescence was not observed. The coexistence of trilayer and monolayer at the final step of the collapse cannot be interpreted exclusively in terms of a thermodynamic phase equilibrium, intervening as an additional factor the anisotropic line tension of the domain. A high line tension implies a high resistance to the domain deformation, and the anisotropy of the line tension implies the lack of coalescence between these domains, which has been experimentally observed by Brewster angle microscopy for us. Under these circumstances, the domains of collapsed material could enclose monolayer regions where the local surface pressure drops thus stopping the collapse process. The collapse of the TSPP/DOMA system is reversible, that is, the return of the three-dimensional material to the monolayer fits into a simple kinetics according to the nucleation-growth-collision theory. As for the collapse, the reverse process is also affected by the line tension of the domains. This paper relates the high line tension and the anisotropic line tension of a given domains with the reversible nature of the collapse process.

Development of simplified process for environmentally resistant cells

NASA Technical Reports Server (NTRS)

King, W. J.

1980-01-01

This report describes a program to develop a simple, foolproof, all vacuum solar cell manufacturing process which can be completely automated and which results in medium efficiency cells which are inherently environmentally resistant. All components of the completed cells are integrated into a monolithic structure with no material interfaces. The exposed materials (SI, Al2O3, Al, Ni) are all resistant to atmospheric attack and the junction, per se, is passivated to prevent long term degradation. Such cells are intended to be incorporated into a simple module consisting basically of a press formed metallic superstructure with a separated glass cover for missile, etc., protection.

BARNARD 59: NO EVIDENCE FOR FURTHER FRAGMENTATION

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

Roman-Zuniga, C. G.; Frau, P.; Girart, J. M.

2012-03-10

The dense molecular clump at the center of the Barnard 59 (B59) complex is the only region in the Pipe Nebula that has formed a small, stellar cluster. The previous analysis of a high-resolution near-IR dust extinction map revealed that the nuclear region in B59 is a massive, mostly quiescent clump of 18.9 M{sub Sun }. The clump shows a monolithic profile, possibly indicating that the clump is on the way to collapse, with no evident fragmentation that could lead to another group of star systems. In this paper, we present new analysis that compares the dust extinction map withmore » a new dust emission radio-continuum map of higher spatial resolution. We confirm that the clump does not show any significant evidence for prestellar fragmentation at scales smaller than those probed previously.« less

Progressive Fracture of Laminated Fiber-Reinforced Composite Stiffened Plate Under Pressure

NASA Technical Reports Server (NTRS)

Gotsis, Pascalis K.; Abdi, Frank; Chamis, Christos C.; Tsouros, Konstantinos

2007-01-01

S-Glass/epoxy laminated fiber-reinforced composite stiffened plate structure with laminate configuration (0/90)5 was simulated to investigate damage and fracture progression, under uniform pressure. For comparison reasons a simple plate was examined, in addition with the stiffened plate. An integrated computer code was used for the simulation. The damage initiation began with matrix failure in tension, continuous with damage and/or fracture progression as a result of additional matrix failure and fiber fracture and followed by additional interply delamination. Fracture through the thickness began when the damage accumulation was 90%. After that stage, the cracks propagate rapidly and the structures collapse. The collapse load for the simple plate is 21.57 MPa (3120 psi) and for the stiffened plate 25.24 MPa (3660 psi).

Porous Ni-Mn oxide nanosheets in situ formed on nickel foam as 3D hierarchical monolith de-NOx catalysts

NASA Astrophysics Data System (ADS)

Cai, Sixiang; Zhang, Dengsong; Shi, Liyi; Xu, Jing; Zhang, Lei; Huang, Lei; Li, Hongrui; Zhang, Jianping

2014-06-01

In this work, we successfully in situ decorated nickel foam with porous Ni-Mn oxide nanosheets (3DH-NM/NF) as 3D hierarchical monolith de-NOx catalysts via a simple hydrothermal reaction and calcination process. The catalysts were carefully examined by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, elemental mapping, X-ray photoelectron spectroscopy, H2 temperature-programmed reduction and NH3 temperature-programmed desorption measurements. The results indicated that the nanosheets are composed of a Ni6Mn1O8 spinel and the metal species are uniformly dispersed in bi-metal oxides. As a result, the strong synergistic effects between the Mn and Ni species have been observed. The active oxygen species, reducible species and acidity are enhanced by the in situ formation of the nanosheets on the surface of nickel foam. These desirable features of 3DH-NM/NF catalysts bring about the excellent de-NOx performance. Moreover, the 3DH-NM/NF catalysts also present good stability and H2O resistance. Based on these favorable properties, 3DH-NM/NF could be considered as a promising candidate for the monolith de-NOx catalysts.In this work, we successfully in situ decorated nickel foam with porous Ni-Mn oxide nanosheets (3DH-NM/NF) as 3D hierarchical monolith de-NOx catalysts via a simple hydrothermal reaction and calcination process. The catalysts were carefully examined by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, elemental mapping, X-ray photoelectron spectroscopy, H2 temperature-programmed reduction and NH3 temperature-programmed desorption measurements. The results indicated that the nanosheets are composed of a Ni6Mn1O8 spinel and the metal species are uniformly dispersed in bi-metal oxides. As a result, the strong synergistic effects between the Mn and Ni species have been observed. The active oxygen species, reducible species and acidity are enhanced by the in situ formation of the nanosheets on the surface of nickel foam. These desirable features of 3DH-NM/NF catalysts bring about the excellent de-NOx performance. Moreover, the 3DH-NM/NF catalysts also present good stability and H2O resistance. Based on these favorable properties, 3DH-NM/NF could be considered as a promising candidate for the monolith de-NOx catalysts. Electronic supplementary information (ESI) available: Experimental details and catalytic performance of the NM/cordierite catalysts, SEM image and EDX analysis of the NF and 3DH-N/NF catalysts, N2 selectivity and catalytic performance under different gas hourly space velocities of the 3DH-NM/NF catalysts. See DOI: 10.1039/c4nr00475b

Collapsed Dark Matter Structures

NASA Astrophysics Data System (ADS)

Buckley, Matthew R.; DiFranzo, Anthony

2018-02-01

The distributions of dark matter and baryons in the Universe are known to be very different: The dark matter resides in extended halos, while a significant fraction of the baryons have radiated away much of their initial energy and fallen deep into the potential wells. This difference in morphology leads to the widely held conclusion that dark matter cannot cool and collapse on any scale. We revisit this assumption and show that a simple model where dark matter is charged under a "dark electromagnetism" can allow dark matter to form gravitationally collapsed objects with characteristic mass scales much smaller than that of a Milky-Way-type galaxy. Though the majority of the dark matter in spiral galaxies would remain in the halo, such a model opens the possibility that galaxies and their associated dark matter play host to a significant number of collapsed substructures. The observational signatures of such structures are not well explored but potentially interesting.

Collapsed Dark Matter Structures.

PubMed

Buckley, Matthew R; DiFranzo, Anthony

2018-02-02

The distributions of dark matter and baryons in the Universe are known to be very different: The dark matter resides in extended halos, while a significant fraction of the baryons have radiated away much of their initial energy and fallen deep into the potential wells. This difference in morphology leads to the widely held conclusion that dark matter cannot cool and collapse on any scale. We revisit this assumption and show that a simple model where dark matter is charged under a "dark electromagnetism" can allow dark matter to form gravitationally collapsed objects with characteristic mass scales much smaller than that of a Milky-Way-type galaxy. Though the majority of the dark matter in spiral galaxies would remain in the halo, such a model opens the possibility that galaxies and their associated dark matter play host to a significant number of collapsed substructures. The observational signatures of such structures are not well explored but potentially interesting.

Alar batten cartilage graft: treatment of internal and external nasal valve collapse.

PubMed

Cervelli, Valerio; Spallone, Diana; Bottini, J Davide; Silvi, Erminia; Gentile, Pietro; Curcio, Beniamino; Pascali, Michele

2009-07-01

The aim of this study was to describe the efficacy of alar batten graft in correcting internal and external nasal valve collapse (i.n.v. and e.n.v.) and evaluate the functional and aesthetic results. From July 2006 to September 2008, 80 patients (54 females and 26 males) underwent alar batten cartilage grafting. The patients were divided into three groups: (1) 55 patients with iatrogenic nasal valve collapse (80% i.n.v., 20% e.n.v.), (2) 15 patients with posttraumatic nasal valve collapse (45% i.n.v., 55% e.n.v.), and (3) 10 patients with congenital nasal valve collapse (100% e.n.v.). Patients were evaluated at 6, 12, 24, and some at 36 months after surgery. The final follow-up was at least 24 months. The results of this study revealed a significant increase in the size of the aperture at the internal or external nasal valve after the application of alar batten grafts. All the patients noted improvement in their nasal airway breathing and in their cosmetic appearance. No major complication was observed. The alar batten graft is a simple, versatile technique for long-term reshaping, repositioning, and reconstruction of the nasal valve collapse.

A Simple Model for Human and Nature Interaction

NASA Astrophysics Data System (ADS)

Motesharrei, S.; Rivas, J.; Kalnay, E.

2012-12-01

There are widespread concerns that current trends in population and resource-use are unsustainable, but the possibilities of an overshoot and collapse remain unclear and controversial. Collapses of civilizations have occurred many times in the past 5000 years, often followed by centuries of economic, intellectual, and population decline. Many different natural and social phenomena have been invoked to explain specific collapses, but a general explanation remains elusive. Two important features seem to appear across societies that have collapsed: Ecological Strain and Economic Stratification. Our new model (Human And Nature DYnamics, HANDY) has just four equations that describe the evolution of Elites, Commoners, Nature, and Wealth. Mechanisms leading to collapse are discussed and the measure "Carrying Capacity" is developed and defined. The model shows that societal collapse can happen due to either one of two independent factors: (1) over-consumption of natural resources, and/or (2) deep inequity between Elites and Commoners. The model also portrays two distinct types of collapse: (i) collapse followed by recovery of nature, and (ii) full collapse. The model suggests that the estimation of Carrying Capacity is a practical means for early detection of a collapse. Collapse can be avoided, and population can reach a sustainable equilibrium, if the rate of depletion of nature is reduced to a sustainable level, and if resources are distributed in a reasonably equitable fashion.; A type-ii (full) collapse is shown in this figure. With high inequality and high depletion, societies are doomed to collapse. Wealth starts to decrease when population rises above the carrying capacity. The large gap between carrying capacity and its maximum is a result of depletion factor being much larger than the sustainable limit. ; It is possible to overshoot, oscillate, and eventually converge to an equilibrium, even in an inequitable society. However, it requires policies that control birth rates and inequality. Additionally, depletion (production) must be kept within a reasonable range.

Estimation of Pharyngeal Collapsibility During Sleep by Peak Inspiratory Airflow.

PubMed

Azarbarzin, Ali; Sands, Scott A; Taranto-Montemurro, Luigi; Oliveira Marques, Melania D; Genta, Pedro R; Edwards, Bradley A; Butler, James; White, David P; Wellman, Andrew

2017-01-01

Pharyngeal critical closing pressure (Pcrit) or collapsibility is a major determinant of obstructive sleep apnea (OSA) and may be used to predict the success/failure of non-continuous positive airway pressure (CPAP) therapies. Since its assessment involves overnight manipulation of CPAP, we sought to validate the peak inspiratory flow during natural sleep (without CPAP) as a simple surrogate measurement of collapsibility. Fourteen patients with OSA attended overnight polysomnography with pneumotachograph airflow. The middle third of the night (non-rapid eye movement sleep [NREM]) was dedicated to assessing Pcrit in passive and active states via abrupt and gradual CPAP pressure drops, respectively. Pcrit is the extrapolated CPAP pressure at which flow is zero. Peak and mid-inspiratory flow off CPAP was obtained from all breaths during sleep (excluding arousal) and compared with Pcrit. Active Pcrit, measured during NREM sleep, was strongly correlated with both peak and mid-inspiratory flow during NREM sleep (r = -0.71, p < .005 and r = -0.64, p < .05, respectively), indicating that active pharyngeal collapsibility can be reliably estimated from simple airflow measurements during polysomnography. However, there was no significant relationship between passive Pcrit, measured during NREM sleep, and peak or mid-inspiratory flow obtained from NREM sleep. Flow measurements during REM sleep were not significantly associated with active or passive Pcrit. Our study demonstrates the feasibility of estimating active Pcrit using flow measurements in patients with OSA. This method may enable clinicians to estimate pharyngeal collapsibility without sophisticated equipment and potentially aid in the selection of patients for non- positive airway pressure therapies. © Sleep Research Society 2016. Published by Oxford University Press on behalf of the Sleep Research Society. All rights reserved. For permissions, please e-mail journals.permissions@oup.com.

Collapse and revival of the Fermi sea in a Bose-Fermi mixture

NASA Astrophysics Data System (ADS)

Iyer, Deepak; Will, Sebastian; Rigol, Marcos

2014-05-01

The collapse and revival of quantum fields is one of the most pristine forms of coherent quantum dynamics far from equilibrium. Until now, it has only been observed in the dynamical evolution of bosonic systems. We report on the first observation of the boson mediated collapse and revival of the Fermi sea in a Bose-Fermi mixture. Specifically, we present a simple model which captures the experimental observations shown in the talk titled Observation of Collapse and Revival Dynamics in the Fermionic Component of a Lattice Bose-Fermi Mixture by Sebastian Will. Our theoretical analysis shows why the results are robust to the presence of harmonic traps during the loading or the time evolution phase. It also makes apparent that the fermionic dynamics is independent of whether the bosonic component consists of a coherent state or localized Fock states with random occupation numbers. Because of the robustness of the experimental results, we argue that this kind of collapse and revival experiment can be used to accurately characterize interactions between bosons and fermions in a lattice.

Retaining Ring Fastener for Solar Panels

NASA Technical Reports Server (NTRS)

Wilson, A. H.

1983-01-01

Simple articulating linkage secures solar panels into supporting framework. Five element linkage collapses into W-shape for easy placement into framework, then expands to form rectangle of same dimensions as those of panel.

Development of new dyes for use in integrated optical sensors.

PubMed

Citterio, D; Rásonyi, S; Spichiger, U E

1996-03-01

New chromoionophores have been developed, focused on NIR applications so that optode membranes may be used in monolithically integrated optical sensors. The wavelength of maximum absorbance has been estimated for a new model compound by the Pariser-Parr-Pople (PPP) method. Several cyanine type dyes have been tested as membrane chromoionophores. Membrane composition has been altered to overcome solubility problems. In this way, simple pH-sensitive optode membranes have been produced.

Simple, monolithic optical element for forward-viewing spectrally encoded endoscopy (Conference Presentation)

NASA Astrophysics Data System (ADS)

Do, Dukho; Kang, Dongkyun; Ikuta, Mitsuhiro; Tearney, Guillermo J.

2016-03-01

Spectrally encoded endoscopy (SEE) is a miniature endoscopic technology that can acquire images of internal organs through a hair-thin probe. While most previously described SEE probes have been side viewing, forward-view (FV)-SEE is advantageous in certain clinical applications as it provides more natural navigation of the probe and has the potential to provide a wider field of view. Prior implementations of FV-SEE used multiple optical elements that increase fabrication complexity and may diminish the robustness of the device. In this paper, we present a new design that uses a monolithic optical element to realize FV-SEE imaging. The optical element is specially designed spacer, fabricated from a 500-μm-glass rod that has a mirror surface on one side and a grating stamped on its distal end. The mirror surface is used to change the incident angle on the grating to diffract the shortest wavelength of the spectrum so that it is parallel to the optical axis. Rotating the SEE optics creates a circular FV-SEE image. Custom-designed software processes FV-SEE images into circular images, which are displayed in real-time. In order to demonstrate this new design, we have constructed the FV-SEE optical element using a 1379 lines/mm diffraction grating. When illuminated with a source with a spectral bandwidth of 420-820 nm, the FV-SEE optical element provides 678 resolvable points per line. The imaging performance of the FV-SEE device was tested by imaging a USAF resolution target. SEE images showed that this new approach generates high quality images in the forward field with a field of view of 58°. Results from this preliminary study demonstrate that we can realize FV-SEE imaging with simple, monolithic, miniature optical element. The characteristics of this FV-SEE configuration will facilitate the development of robust miniature endoscopes for a variety of medical imaging applications.

Methacrylate monolithic columns functionalized with epinephrine for capillary electrochromatography applications.

PubMed

Carrasco-Correa, Enrique Javier; Ramis-Ramos, Guillermo; Herrero-Martínez, José Manuel

2013-07-12

Epinephrine-bonded polymeric monoliths for capillary electrochromatography (CEC) were developed by nucleophilic substitution reaction of epoxide groups of poly(glycidyl-methacrylate-co-ethylenedimethacrylate) (poly(GMA-co-EDMA)) monoliths using epinephrine as nucleophilic reagent. The ring opening reaction under dynamic conditions was optimized. Successful chemical modification of the monolith surface was ascertained by in situ Raman spectroscopy characterization. In addition, the amount of epinephrine groups that was bound to the monolith surface was evaluated by oxidation of the catechol groups with Ce(IV), followed by spectrophotometric measurement of unreacted Ce(IV). About 9% of all theoretical epoxide groups of the parent monolith were bonded to epinephrine. The chromatographic behavior of the epinephrine-bonded monolith in CEC conditions was assessed with test mixtures of alkyl benzenes, aniline derivatives and substituted phenols. In comparison to the poly(GMA-co-EDMA) monoliths, the epinephrine-bonded monoliths exhibited a much higher retention and slight differences in selectivity. The epinephrine-bonded monolith was further modified by oxidation with a Ce(IV) solution and compared with the epinephrine-bonded monoliths. The resulting monolithic stationary phases were evaluated in terms of reproducibility, giving RSD values below 9% in the parameters investigated. Copyright © 2013 Elsevier B.V. All rights reserved.

Progressive fracture of polymer matrix composite structures: A new approach

NASA Technical Reports Server (NTRS)

Chamis, C. C.; Murthy, P. L. N.; Minnetyan, L.

1992-01-01

A new approach independent of stress intensity factors and fracture toughness parameters has been developed and is described for the computational simulation of progressive fracture of polymer matrix composite structures. The damage stages are quantified based on physics via composite mechanics while the degradation of the structural behavior is quantified via the finite element method. The approach account for all types of composite behavior, structures, load conditions, and fracture processes starting from damage initiation, to unstable propagation and to global structural collapse. Results of structural fracture in composite beams, panels, plates, and shells are presented to demonstrate the effectiveness and versatility of this new approach. Parameters and guidelines are identified which can be used as criteria for structural fracture, inspection intervals, and retirement for cause. Generalization to structures made of monolithic metallic materials are outlined and lessons learned in undertaking the development of new approaches, in general, are summarized.

Development of the Monolith Froth Reactor for Catalytic Wet Oxidation of CELSS Model Wastes

NASA Technical Reports Server (NTRS)

Fisher, John W.; Abraham, Martin

1993-01-01

The aqueous phase oxidation of acetic acid, used as a model compound for the treatment of CELSS (Controlled Ecological Life Support System) waste, was carried out in the monolith froth reactor which utilizes two-phase flow in the monolith channels. The catalytic oxidation of acetic acid was carried out over a Pt/Al2O3 catalyst at temperatures and pressures below the critical point of water. The effect of externally controllable parameters (temperature, liquid flow rate, distributor plate orifice size, pitch, and catalyst distance from the distributor plate) on the rate of acetic acid oxidation was investigated. Results indicate reaction rate increased with increasing temperature and exhibited a maximum with respect to liquid flow rate. The apparent activation energy calculated from reaction rate data was 99.7 kJ/mol. This value is similar to values reported for the oxidation of acetic acid in other systems and is comparable to intrinsic values calculated for oxidation reactions. The kinetic data were modeled using simple power law kinetics. The effect of "froth" feed system characteristics was also investigated. Results indicate that the reaction rate exhibits a maximum with respect to distributor plate orifice size, pitch, and catalyst distance from the distributor plate. Fundamental results obtained were used to extrapolate where the complete removal of acetic acid would be obtained and for the design and operation of a full scale CELSS treatment system.

Monolithically interconnected GaAs solar cells: A new interconnection technology for high voltage solar cell output

NASA Astrophysics Data System (ADS)

Dinetta, L. C.; Hannon, M. H.

1995-10-01

Photovoltaic linear concentrator arrays can benefit from high performance solar cell technologies being developed at AstroPower. Specifically, these are the integration of thin GaAs solar cell and epitaxial lateral overgrowth technologies with the application of monolithically interconnected solar cell (MISC) techniques. This MISC array has several advantages which make it ideal for space concentrator systems. These are high system voltage, reliable low cost monolithically formed interconnections, design flexibility, costs that are independent of array voltage, and low power loss from shorts, opens, and impact damage. This concentrator solar cell will incorporate the benefits of light trapping by growing the device active layers over a low-cost, simple, PECVD deposited silicon/silicon dioxide Bragg reflector. The high voltage-low current output results in minimal 12R losses while properly designing the device allows for minimal shading and resistance losses. It is possible to obtain open circuit voltages as high as 67 volts/cm of solar cell length with existing technology. The projected power density for the high performance device is 5 kW/m for an AMO efficiency of 26% at 1 5X. Concentrator solar cell arrays are necessary to meet the power requirements of specific mission platforms and can supply high voltage power for electric propulsion systems. It is anticipated that the high efficiency, GaAs monolithically interconnected linear concentrator solar cell array will enjoy widespread application for space based solar power needs. Additional applications include remote man-portable or ultra-light unmanned air vehicle (UAV) power supplies where high power per area, high radiation hardness and a high bus voltage or low bus current are important. The monolithic approach has a number of inherent advantages, including reduced cost per interconnect and increased reliability of array connections. There is also a high potential for a large number of consumer products. Dual-use applications can include battery chargers and remote power supplies for consumer electronics products such as portable telephones/beepers, portable radios, CD players, dashboard radar detectors, remote walkway lighting, etc.

The influence of architecture on the elasticity and strength of Si(3)N(4)/BN fibrous-monolithic ceramic laminates

NASA Astrophysics Data System (ADS)

King, Bruce H.

Fibrous-monolithic ceramics are a class of material with many similarities to layered ceramic composites. Like layered composites, fibrous monoliths depend on a weak interphase to promote crack deflection and energy absorption, avoiding catastrophic failure. However, in a fibrous monolith, the interphase surrounds fiber-like "cells" of the strong phase, forming a continuous, 2-dimensional honeycomb network. In the most simple architecture, all cells are aligned unidirectionally. More complex architectures are easily produced by varying the orientation of successive layers relative to each other. The Young's modulus of the unidirectional architecture is predicted accurately along principal axes using a "brick" model, while the modulus at angles between 0sp° and 90sp° is predicted using laminate theory. Laminate theory may also be used to accurately predict the Young's modulus of multidirectional architectures such as a cross-ply 0sp°/90sp° and a quasi-isotropic 0sp°/{±}45sp°/90sp°. Unidirectional fibrous monolithic ceramics are linear elastic in flexure until the first major failure event. The flexural strength of the unidirectional architecture tested at orientations between 0sp° and 90sp° is observed to fall into three distinct regions. Between 0sp° and 10sp° the strength is a constant 450 MPa, but between 10sp° and 45sp°, it gradually drops to 80 MPa. Above 45sp° the strength remains essentially constant. Between 0sp° and 30sp°, the strength is accurately predicted using the Maximum Stress theory. Above 30sp°, the strength is predicted using the Tsai-Hill model. The multidirectional architectures exhibit nonlinearity in flexural loading prior to the peak stress. Cyclic loading experiments indicate that this nonlinearity is a result-of microcracking in the boron nitride cell boundaries of the off-axis layers. The cross-ply architecture exhibits a strength of 334 ± 35 MPa, while the quasi-isotropic has a strength of 255 ± 22 MPa. The models developed to describe the unidirectional architecture may be extended to predict upper and lower bounds on the strength of multidirectional architectures.

Monolithically interconnected GaAs solar cells: A new interconnection technology for high voltage solar cell output

NASA Technical Reports Server (NTRS)

Dinetta, L. C.; Hannon, M. H.

1995-01-01

Photovoltaic linear concentrator arrays can benefit from high performance solar cell technologies being developed at AstroPower. Specifically, these are the integration of thin GaAs solar cell and epitaxial lateral overgrowth technologies with the application of monolithically interconnected solar cell (MISC) techniques. This MISC array has several advantages which make it ideal for space concentrator systems. These are high system voltage, reliable low cost monolithically formed interconnections, design flexibility, costs that are independent of array voltage, and low power loss from shorts, opens, and impact damage. This concentrator solar cell will incorporate the benefits of light trapping by growing the device active layers over a low-cost, simple, PECVD deposited silicon/silicon dioxide Bragg reflector. The high voltage-low current output results in minimal 12R losses while properly designing the device allows for minimal shading and resistance losses. It is possible to obtain open circuit voltages as high as 67 volts/cm of solar cell length with existing technology. The projected power density for the high performance device is 5 kW/m for an AMO efficiency of 26% at 1 5X. Concentrator solar cell arrays are necessary to meet the power requirements of specific mission platforms and can supply high voltage power for electric propulsion systems. It is anticipated that the high efficiency, GaAs monolithically interconnected linear concentrator solar cell array will enjoy widespread application for space based solar power needs. Additional applications include remote man-portable or ultra-light unmanned air vehicle (UAV) power supplies where high power per area, high radiation hardness and a high bus voltage or low bus current are important. The monolithic approach has a number of inherent advantages, including reduced cost per interconnect and increased reliability of array connections. There is also a high potential for a large number of consumer products. Dual-use applications can include battery chargers and remote power supplies for consumer electronics products such as portable telephones/beepers, portable radios, CD players, dashboard radar detectors, remote walkway lighting, etc.

DEVELOPMENT OF AN AFFINITY SILICA MONOLITH CONTAINING HUMAN SERUM ALBUMIN FOR CHIRAL SEPARATIONS

PubMed Central

Mallik, Rangan; Hage, David S.

2008-01-01

An affinity monolith based on silica and containing immobilized human serum albumin (HSA) was developed and evaluated in terms of its binding, efficiency and selectivity in chiral separations. The results were compared with data obtained for the same protein when used as a chiral stationary phase with HPLC-grade silica particles or a monolith based on a copolymer of glycidyl methacrylate (GMA) and ethylene dimethacrylate (EDMA). The surface coverage of HSA in the silica monolith was similar to values obtained with silica particles and a GMA/EDMA monolith. However, the higher surface area of the silica monolith gave a material that contained 1.3- to 2.2-times more immobilized HSA per unit volume when compared to silica particles or a GMA/EDMA monolith. The retention, efficiency and resolving power of the HSA silica monolith were evaluated using two chiral analytes: D/L-tryptophan and R/S-warfarin. The separation of R- and S-ibuprofen was also considered. The HSA silica monolith gave higher retention and higher or comparable resolution and efficiency when compared with HSA columns that contained silica particles or a GMA/EDMA monolith. The silica monolith also gave lower back pressures and separation impedances than these other materials. It was concluded that silica monoliths can be valuable alternatives to silica particles or GMA/EDMA monoliths when used with immobilized HSA as a chiral stationary phase. PMID:17475436

Binary Colloidal Alloy Test-5: Phase Separation

NASA Technical Reports Server (NTRS)

Lynch, Matthew; Weitz, David A.; Lu, Peter J.

2008-01-01

The Binary Colloidal Alloy Test - 5: Phase Separation (BCAT-5-PhaseSep) experiment will photograph initially randomized colloidal samples onboard the ISS to determine their resulting structure over time. This allows the scientists to capture the kinetics (evolution) of their samples, as well as the final equilibrium state of each sample. BCAT-5-PhaseSep studies collapse (phase separation rates that impact product shelf-life); in microgravity the physics of collapse is not masked by being reduced to a simple top and bottom phase as it is on Earth.

Sequestration of vacuum energy and the end of the universe.

PubMed

Kaloper, Nemanja; Padilla, Antonio

2015-03-13

Recently, we proposed a mechanism for sequestering the standard model vacuum energy that predicts that the Universe will collapse. Here we present a simple mechanism for bringing about this collapse, employing a scalar field whose potential is linear and becomes negative, providing the negative energy density required to end the expansion. The slope of the potential is chosen to allow for the expansion to last until the current Hubble time, about 10^{10} years, to accommodate our Universe. Crucially, this choice is technically natural due to a shift symmetry. Moreover, vacuum energy sequestering selects radiatively stable initial conditions for the collapse, which guarantee that immediately before the turnaround the Universe is dominated by the linear potential which drives an epoch of accelerated expansion for at least an e fold. Thus, a single, technically natural choice for the slope ensures that the collapse is imminent and is preceded by the current stage of cosmic acceleration, giving a new answer to the "why now?"

Precombination Cloud Collapse and Baryonic Dark Matter

NASA Technical Reports Server (NTRS)

Hogan, Craig J.

1993-01-01

A simple spherical model of dense baryon clouds in the hot big bang 'strongly nonlinear primordial isocurvature baryon fluctuations' is reviewed and used to describe the dependence of cloud behavior on the model parameters, baryon mass, and initial over-density. Gravitational collapse of clouds before and during recombination is considered including radiation diffusion and trapping, remnant type and mass, and effects on linear large-scale fluctuation modes. Sufficiently dense clouds collapse early into black holes with a minimum mass of approx. 1 solar mass, which behave dynamically like collisionless cold dark matter. Clouds below a critical over-density, however, delay collapse until recombination, remaining until then dynamically coupled to the radiation like ordinary diffuse baryons, and possibly producing remnants of other kinds and lower mass. The mean density in either type of baryonic remnant is unconstrained by observed element abundances. However, mixed or unmixed spatial variations in abundance may survive in the diffuse baryon and produce observable departures from standard predictions.

Damping in Space Constructions

NASA Astrophysics Data System (ADS)

de Vreugd, Jan; de Lange, Dorus; Winters, Jasper; Human, Jet; Kamphues, Fred; Tabak, Erik

2014-06-01

Monolithic structures are often used in optomechanical designs for space applications to achieve high dimensional stability and to prevent possible backlash and friction phenomena. The capacity of monolithic structures to dissipate mechanical energy is however limited due to the high Q-factor, which might result in high stresses during dynamic launch loads like random vibration, sine sweeps and shock. To reduce the Q-factor in space applications, the effect of constrained layer damping (CLD) is investigated in this work. To predict the damping increase, the CLD effect is implemented locally at the supporting struts in an existing FE model of an optical instrument. Numerical simulations show that the effect of local damping treatment in this instrument could reduce the vibrational stresses with 30-50%. Validation experiments on a simple structure showed good agreement between measured and predicted damping properties. This paper presents material characterization, material modeling, numerical implementation of damping models in finite element code, numerical results on space hardware and the results of validation experiments.

Determination of steroid sex hormones in wastewater by stir bar sorptive extraction based on poly(vinylpyridine-ethylene dimethacrylate) monolithic material and liquid chromatographic analysis.

PubMed

Huang, Xiaojia; Lin, Jianbin; Yuan, Dongxing; Hu, Rongzong

2009-04-17

In this study, a simple and rapid method was developed for the determination of seven steroid hormones in wastewater. Sample preparation and analysis were performed by stir bar sorptive extraction (SBSE) based on poly(vinylpyridine-ethylene dimethacrylate) monolithic material (SBSEM) combined with high-performance liquid chromatography with diode array detection. To achieve the optimum extraction performance, several main parameters, including extraction and desorption time, pH value and contents of inorganic salt in the sample matrix, were investigated. Under the optimized experimental conditions, the method showed good linearity and repeatability, as well as advantages such as sensitivity, simplicity, low cost and high feasibility. The extraction performance of SBSEM to the target compounds also compared with commercial SBSE which used polydimethylsiloxane as coating. Finally, the proposed method was successfully applied to the determination of the target compounds in wastewater samples. The recoveries of spiked target compounds in real samples ranged from 48.2% to 110%.

Effect of bioparticle size on dispersion and retention in monolithic and perfusive beds

PubMed Central

Trilisky, Egor I.; Lenhoff, Abraham M.

2010-01-01

Single-component pulse response studies were used to compare the retention and transport behavior of small molecules, proteins, and a virus on commercially available monolithic and perfusive ion-exchangers. Temporal distortion and extra-column effects were corrected for using a simple algorithm based on the method of moments. It was found that temporal distortion is inversely related to the number of theoretical plates. With increasing bioparticle size, retention increased and the transition from a non-eluting to a non-adsorbing state with increasing ionic strength became more abrupt. Both of these observations are qualitatively explained by calculations of particle-surface electrostatic attractive energy. Calculations also show that, for sufficiently large bioparticles, such as viruses or cells, hydrodynamic drag can promote elution. Under non-adsorbing conditions, plate height increased only weakly with flow rate and the skew remained unchanged. With increasing retention, plate height increased dramatically for proteins. Plate height was scaled by permeability rather than bead diameter to enable comparison among different stationary phases. PMID:20951383

Photolithography-Based Patterning of Liquid Metal Interconnects for Monolithically Integrated Stretchable Circuits.

PubMed

Park, Chan Woo; Moon, Yu Gyeong; Seong, Hyejeong; Jung, Soon Won; Oh, Ji-Young; Na, Bock Soon; Park, Nae-Man; Lee, Sang Seok; Im, Sung Gap; Koo, Jae Bon

2016-06-22

We demonstrate a new patterning technique for gallium-based liquid metals on flat substrates, which can provide both high pattern resolution (∼20 μm) and alignment precision as required for highly integrated circuits. In a very similar manner as in the patterning of solid metal films by photolithography and lift-off processes, the liquid metal layer painted over the whole substrate area can be selectively removed by dissolving the underlying photoresist layer, leaving behind robust liquid patterns as defined by the photolithography. This quick and simple method makes it possible to integrate fine-scale interconnects with preformed devices precisely, which is indispensable for realizing monolithically integrated stretchable circuits. As a way for constructing stretchable integrated circuits, we propose a hybrid configuration composed of rigid device regions and liquid interconnects, which is constructed on a rigid substrate first but highly stretchable after being transferred onto an elastomeric substrate. This new method can be useful in various applications requiring both high-resolution and precisely aligned patterning of gallium-based liquid metals.

Collapse Mechanisms Of Masonry Structures

NASA Astrophysics Data System (ADS)

Zuccaro, G.; Rauci, M.

2008-07-01

The paper outlines a possible approach to typology recognition, safety check analyses and/or damage measuring taking advantage by a multimedia tool (MEDEA), tracing a guided procedure useful for seismic safety check evaluation and post event macroseismic assessment. A list of the possible collapse mechanisms observed in the post event surveys on masonry structures and a complete abacus of the damages are provided in MEDEA. In this tool a possible combination between a set of damage typologies and each collapse mechanism is supplied in order to improve the homogeneity of the damages interpretation. On the other hand recent researches of one of the author have selected a number of possible typological vulnerability factors of masonry buildings, these are listed in the paper and combined with potential collapse mechanisms to be activated under seismic excitation. The procedure takes place from simple structural behavior models, derived from the Umbria-Marche earthquake observations, and tested after the San Giuliano di Puglia event; it provides the basis either for safety check analyses of the existing buildings or for post-event structural safety assessment and economic damage evaluation. In the paper taking advantage of MEDEA mechanisms analysis, mainly developed for the post event safety check surveyors training, a simple logic path is traced in order to approach the evaluation of the masonry building safety check. The procedure starts from the identification of the typological vulnerability factors to derive the potential collapse mechanisms and their collapse multipliers and finally addresses the simplest and cheapest strengthening techniques to reduce the original vulnerability. The procedure has been introduced in the Guide Lines of the Regione Campania for the professionals in charge of the safety check analyses and the buildings strengthening in application of the national mitigation campaign introduced by the Ordinance of the Central Government n. 3362/03. The main cases of out of plane mechanisms are analyzed and a possible innovative theory for masonry building vulnerability assessment, based on limit state analyses, is outlined. The paper report the first step of a research granted by the Department of the Civil Protection to Reluis within the research program of Line 10.

Collapse Mechanisms Of Masonry Structures

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

Zuccaro, G.; Rauci, M.

2008-07-08

The paper outlines a possible approach to typology recognition, safety check analyses and/or damage measuring taking advantage by a multimedia tool (MEDEA), tracing a guided procedure useful for seismic safety check evaluation and post event macroseismic assessment. A list of the possible collapse mechanisms observed in the post event surveys on masonry structures and a complete abacus of the damages are provided in MEDEA. In this tool a possible combination between a set of damage typologies and each collapse mechanism is supplied in order to improve the homogeneity of the damages interpretation. On the other hand recent researches of onemore » of the author have selected a number of possible typological vulnerability factors of masonry buildings, these are listed in the paper and combined with potential collapse mechanisms to be activated under seismic excitation. The procedure takes place from simple structural behavior models, derived from the Umbria-Marche earthquake observations, and tested after the San Giuliano di Puglia event; it provides the basis either for safety check analyses of the existing buildings or for post-event structural safety assessment and economic damage evaluation. In the paper taking advantage of MEDEA mechanisms analysis, mainly developed for the post event safety check surveyors training, a simple logic path is traced in order to approach the evaluation of the masonry building safety check. The procedure starts from the identification of the typological vulnerability factors to derive the potential collapse mechanisms and their collapse multipliers and finally addresses the simplest and cheapest strengthening techniques to reduce the original vulnerability. The procedure has been introduced in the Guide Lines of the Regione Campania for the professionals in charge of the safety check analyses and the buildings strengthening in application of the national mitigation campaign introduced by the Ordinance of the Central Government n. 3362/03. The main cases of out of plane mechanisms are analyzed and a possible innovative theory for masonry building vulnerability assessment, based on limit state analyses, is outlined. The paper report the first step of a research granted by the Department of the Civil Protection to Reluis within the research program of Line 10.« less

A poly(vinyl alcohol)/sodium alginate blend monolith with nanoscale porous structure

PubMed Central

2013-01-01

A stimuli-responsive poly(vinyl alcohol) (PVA)/sodium alginate (SA) blend monolith with nanoscale porous (mesoporous) structure is successfully fabricated by thermally impacted non-solvent induced phase separation (TINIPS) method. The PVA/SA blend monolith with different SA contents is conveniently fabricated in an aqueous methanol without any templates. The solvent suitable for the fabrication of the present blend monolith by TINIPS is different with that of the PVA monolith. The nanostructural control of the blend monolith is readily achieved by optimizing the fabrication conditions. Brunauer Emmett Teller measurement shows that the obtained blend monolith has a large surface area. Pore size distribution plot for the blend monolith obtained by the non-local density functional theory method reveals the existence of the nanoscale porous structure. Fourier transform infrared analysis reveals the strong interactions between PVA and SA. The pH-responsive property of the blend monolith is investigated on the basis of swelling ratio in different pH solutions. The present blend monolith of biocompatible and biodegradable PVA and SA with nanoscale porous structure has large potential for applications in biomedical and environmental fields. PMID:24093494

A poly(vinyl alcohol)/sodium alginate blend monolith with nanoscale porous structure.

PubMed

Sun, Xiaoxia; Uyama, Hiroshi

2013-10-04

A stimuli-responsive poly(vinyl alcohol) (PVA)/sodium alginate (SA) blend monolith with nanoscale porous (mesoporous) structure is successfully fabricated by thermally impacted non-solvent induced phase separation (TINIPS) method. The PVA/SA blend monolith with different SA contents is conveniently fabricated in an aqueous methanol without any templates. The solvent suitable for the fabrication of the present blend monolith by TINIPS is different with that of the PVA monolith. The nanostructural control of the blend monolith is readily achieved by optimizing the fabrication conditions. Brunauer Emmett Teller measurement shows that the obtained blend monolith has a large surface area. Pore size distribution plot for the blend monolith obtained by the non-local density functional theory method reveals the existence of the nanoscale porous structure. Fourier transform infrared analysis reveals the strong interactions between PVA and SA. The pH-responsive property of the blend monolith is investigated on the basis of swelling ratio in different pH solutions. The present blend monolith of biocompatible and biodegradable PVA and SA with nanoscale porous structure has large potential for applications in biomedical and environmental fields.

Long-term outcome of permanent tracheostomy in 15 dogs with severe laryngeal collapse secondary to brachycephalic airway obstructive syndrome.

PubMed

Gobbetti, Matteo; Romussi, Stefano; Buracco, Paolo; Bronzo, Valerio; Gatti, Samuele; Cantatore, Matteo

2018-06-12

To report the long-term outcome of permanent tracheostomy for the management of severe laryngeal collapse secondary to brachycephalic airway obstructive syndrome. Retrospective case series. Fifteen brachycephalic dogs with severe laryngeal collapse treated with permanent tracheostomy. Follow-up data were obtained from medical records or via telephone conversation with the owners. The Kaplan-Meier estimator was used to calculate median survival time. Death was classified as related or unrelated to tracheostomy surgery. Complications were classified as major when they were life-threatening or required revision surgery. Owners were asked to classify the postoperative quality of life as improved, unchanged, or worse and the management of the stoma as simple or demanding. The median survival time was 100 days. Major complications were diagnosed in 12 of 15 (80%) dogs, resulting in death in 8 (median survival time 15 days) and revision surgery in 4 dogs. Seven of 15 (47%) dogs died of unrelated causes or were alive at the end of the study (median survival time 1982 days). The postoperative quality of life of 9 dogs was judged as markedly improved. Stoma management was defined as simple in 8 dogs and demanding in 4. Permanent tracheostomy was associated with a high risk of complications and postoperative death in brachycephalic dogs. However, long-term survival (exceeding 5 years) with a good quality of life was documented in 5 of 15 dogs. Permanent tracheostomy is a suitable salvage option in brachycephalic dogs with severe laryngeal collapse that did not improve following more conservative surgeries. © 2018 The American College of Veterinary Surgeons.

Facile fabrication of mesoporous poly(ethylene-co-vinyl alcohol)/chitosan blend monoliths.

PubMed

Wang, Guowei; Xin, Yuanrong; Uyama, Hiroshi

2015-11-05

Poly(ethylene-co-vinyl alcohol) (EVOH)/chitosan blend monoliths were fabricated by thermally-induced phase separation method. Chitosan was successfully incorporated into the polymeric monolith by selecting EVOH as the main component of the monolith. SEM images exhibit that the chitosan was located on the inner surface of the monolith. Fourier-transform infrared analysis and elemental analysis indicate the successful blend of EVOH and chitosan. BET results show that the blend monoliths had high specific surface area and uniform mesopore structure. Good adsorption ability toward various heavy metal ions was found in the blend monoliths due to the large chelation capacity of chitosan. The blend monoliths have potential application for waste water purification or bio-related applications. Copyright © 2015 Elsevier Ltd. All rights reserved.

Surface modified aerogel monoliths

NASA Technical Reports Server (NTRS)

Leventis, Nicholas (Inventor); Johnston, James C. (Inventor); Kuczmarski, Maria A. (Inventor); Meador, Mary Ann B. (Inventor)

2013-01-01

This invention comprises reinforced aerogel monoliths such as silica aerogels having a polymer coating on its outer geometric surface boundary, and to the method of preparing said aerogel monoliths. The polymer coatings on the aerogel monoliths are derived from polymer precursors selected from the group consisting of isocyanates as a precursor, precursors of epoxies, and precursors of polyimides. The coated aerogel monoliths can be modified further by encapsulating the aerogel with the polymer precursor reinforced with fibers such as carbon or glass fibers to obtain mechanically reinforced composite encapsulated aerogel monoliths.

Full of Sound and Fury, Signifying Nothing? A Reply to Dave Hill's "Race and Class in Britain: A Critique of the Statistical Basis for Critical Race Theory in Britain"

ERIC Educational Resources Information Center

Gillborn, David

2010-01-01

This paper is a reply to an earlier piece by Dave Hill, in this journal, that attacked critical race theory (CRT) in general and my own work in particular. I begin with a brief introduction to CRT which highlights the differences between the reality, of a broad and dynamic approach, as opposed to the simple and monolithic version constructed by…

A grid amplifier

NASA Technical Reports Server (NTRS)

Kim, Moonil; Weikle, Robert M., II; Hacker, Jonathan B.; Delisio, Michael P.; Rutledge, David B.; Rosenberg, James J.; Smith, R. P.

1991-01-01

A 50-MESFET grid amplifier is reported that has a gain of 11 dB at 3.3 GHz. The grid isolates the input from the output by using vertical polarization for the input beam and horizontal polarization for the transmitted output beam. The grid unit cell is a two-MESFET differential amplifier. A simple calibration procedure allows the gain to be calculated from a relative power measurement. This grid is a hybrid circuit, but the structure is suitable for fabrication as a monolithic wafer-scale integrated circuit, particularly at millimeter wavelengths.

Acoustic fluidization and the scale dependence of impact crater morphology

NASA Technical Reports Server (NTRS)

Melosh, H. J.; Gaffney, E. S.

1983-01-01

A phenomenological Bingham plastic model has previously been shown to provide an adequate description of the collapse of impact craters. This paper demonstrates that the Bingham parameters may be derived from a model in which acoustic energy generated during excavation fluidizes the rock debris surrounding the crater. Experimental support for the theoretical flow law is presented. Although the Bingham yield stress cannot be computed without detailed knowledge of the initial acoustic field, the Bingham viscosity is derived from a simple argument which shows that it increases as the 3/2 power of crater diameter, consistent with observation. Crater collapse may occur in material with internal dissipation Q as low as 100, comparable to laboratory observations of dissipation in granular materials. Crater collapse thus does not require that the acoustic field be regenerated during flow.

Microfluidic devices and methods including porous polymer monoliths

DOEpatents

Hatch, Anson V; Sommer, Gregory J; Singh, Anup K; Wang, Ying-Chih; Abhyankar, Vinay V

2014-04-22

Microfluidic devices and methods including porous polymer monoliths are described. Polymerization techniques may be used to generate porous polymer monoliths having pores defined by a liquid component of a fluid mixture. The fluid mixture may contain iniferters and the resulting porous polymer monolith may include surfaces terminated with iniferter species. Capture molecules may then be grafted to the monolith pores.

Microfluidic devices and methods including porous polymer monoliths

DOEpatents

Hatch, Anson V.; Sommer, Gregory j.; Singh, Anup K.; Wang, Ying-Chih; Abhyankar, Vinay

2015-12-01

Microfluidic devices and methods including porous polymer monoliths are described. Polymerization techniques may be used to generate porous polymer monoliths having pores defined by a liquid component of a fluid mixture. The fluid mixture may contain iniferters and the resulting porous polymer monolith may include surfaces terminated with iniferter species. Capture molecules may then be grafted to the monolith pores.

Preparation of novel beta-cyclodextrin functionalized monolith and its application in chiral separation.

PubMed

Lv, Yongqin; Mei, Danping; Pan, Xinxin; Tan, Tianwei

2010-09-15

A novel beta-cyclodextrin (beta-CD) functionalized organic polymer monolith was prepared by covalently bonding ethylenediamine-beta-CD (EDA-beta-CD) to poly(glycidyl methacrylate-co-ethylene glycol dimethacrylate) (poly(GMA-co-EGDMA)) monolith via ring opening reaction of epoxy groups. SEM characterization was performed to confirm the homogeneity of the monolithic polymer. The resulting monolith was then characterized by DSC and XPS elemental analysis to study the thermal stability of the monolith, and to prove the successful immobilization of beta-CD on the polymer substrate. The beta-CD ligand density of 0.68 mmol g(-1) was obtained for the modified monolith, indicating the high reactivity and efficiency of the EDA-beta-CD modifier. The ethylenediamine-beta-CD functionalized monoliths were used for the chiral separation of ibuprofen racemic mixture and showed promising results. Copyright (c) 2010 Elsevier B.V. All rights reserved.

Monolithic THz Frequency Multipliers

NASA Technical Reports Server (NTRS)

Erickson, N. R.; Narayanan, G.; Grosslein, R. M.; Martin, S.; Mehdi, I.; Smith, P.; Coulomb, M.; DeMartinez, G.

2001-01-01

Frequency multipliers are required as local oscillator sources for frequencies up to 2.7 THz for FIRST and airborne applications. Multipliers at these frequencies have not previously been demonstrated, and the object of this work was to show whether such circuits are really practical. A practical circuit is one which not only performs as well as is required, but also can be replicated in a time that is feasible. As the frequency of circuits is increased, the difficulties in fabrication and assembly increase rapidly. Building all of the circuit on GaAs as a monolithic circuit is highly desirable to minimize the complexity of assembly, but at the highest frequencies, even a complete monolithic circuit is extremely small, and presents serious handling difficulty. This is compounded by the requirement for a very thin substrate. Assembly can become very difficult because of handling problems and critical placement. It is very desirable to make the chip big enough to that it can be seen without magnification, and strong enough that it may be picked up with tweezers. Machined blocks to house the chips present an additional challenge. Blocks with complex features are very expensive, and these also imply very critical assembly of the parts. It would be much better if the features in the block were as simple as possible and non-critical to the function of the chip. In particular, grounding and other electrical interfaces should be done in a manner that is highly reproducible.

Monolithic silica spin column extraction and simultaneous derivatization of amphetamines and 3,4-methylenedioxyamphetamines in human urine for gas chromatographic-mass spectrometric detection.

PubMed

Nakamoto, Akihiro; Nishida, Manami; Saito, Takeshi; Kishiyama, Izumi; Miyazaki, Shota; Murakami, Katsunori; Nagao, Masataka; Namura, Akira

2010-02-19

A simple, sensitive, and specific method with gas chromatography-mass spectrometry was developed for simultaneous extraction and derivatization of amphetamines (APs) and 3,4-methylenedioxyamphetamines (MDAs) in human urine by using a monolithic silica spin column. All the procedures, such as sample loading, washing, and elution were performed by centrifugation. APs and MDAs in urine were adsorbed on the monolithic silica and derivatized with propyl chloroformate in the column. Methamphetamine-d(5) was used as an internal standard. The linear ranges were 0.01-5.0 microg mL(-1) for methamphetamine (MA) and 3,4-methylenedioxymethamphetamine (MDMA) and 0.02-5.0 microg mL(-1) for amphetamine (AP) and 3,4-methylenedioxyamphetamine (MDA) (coefficient of correlation > or = 0.995). The recovery of APs and MDAs in urine was 84-94%, and the relative standard deviation of the intra- and interday reproducibility for urine samples containing 0.1, 1.0, and 4.0 microg mL(-1) of APs and MDAs ranged from 1.4% to 13.6%. The lowest detection limit (signal-to-noise ratio > or = 3) in urine was 5 ng mL(-1) for MA and MDMA and 10 ng mL(-1) for AP and MDA. The proposed method can be used to perform simultaneous extraction and derivatization on spin columns that have been loaded with a small quantity of solvent by using centrifugation. Copyright 2009 Elsevier B.V. All rights reserved.

Development of the Monolith Froth Reactor for Catalytic Wet Oxidation of CELSS Model Wastes

NASA Technical Reports Server (NTRS)

Abraham, Martin; Fisher, John W.

1995-01-01

The aqueous phase oxidation of acetic acid, used as a model compound for the treatment of CELSS (Controlled Ecological Life Support System) waste, was carried out in the monolith froth reactor which utilizes two-phase flow in the monolith channels. The catalytic oxidation of acetic acid was carried out over a Pt/Al2O3 catalyst, prepared at The University of Tulsa, at temperatures and pressures below the critical point of water. The effect of externally controllable parameters (temperature, liquid flow rate, distributor plate orifice size, pitch, and catalyst distance from the distributor plate) on the rate of acetic acid oxidation was investigated. Results indicate reaction rate increased with increasing temperature and exhibited a maximum with respect to liquid flow rate. The apparent activation energy calculated from reaction rate data was 99.7 kJ/mol. This value is similar to values reported for the oxidation of acetic acid in other systems and is comparable to intrinsic values calculated for oxidation reactions. The kinetic data were modeled using simple power law kinetics. The effect of "froth" feed system characteristics was also investigated. Results indicate that the reaction rate exhibits a maximum with respect to distributor plate orifice size, pitch, and catalyst distance from the distributor plate. Fundamental results obtained were used to extrapolate where the complete removal of acetic acid would be obtained and for the design and operation of a full scale CELSS treatment system.

Preparation of acryloyl β-cyclodextrin-silica hybrid monolithic column and its application in pipette tip solid-phase extraction and HPLC analysis of methyl parathion and fenthion.

PubMed

Chen, Ling; Dang, Xueping; Ai, Youhong; Chen, Huaixia

2018-05-07

An acryloyl β-cyclodextrin-silica hybrid monolithic column for pipette tip solid-phase extraction and high-performance liquid chromatography determination of methyl parathion and fenthion have been prepared through a sol-gel polymerization method. The synthesis conditions, including the volume of cross-linker and the ratio of inorganic solution to organic solution, were optimized. The prepared monolithic column was characterized by thermogravimetric analysis, scanning electron microscopy and Fourier transform infrared spectroscopy. The eluent type, volume and flow rate, sample volume, flow rate, acidity and ionic strength were optimized in detail. Under the optimized conditions, a simple and sensitive pipette tip solid-phase extraction with high-performance liquid chromatography method was developed for the determination of methyl parathion and fenthion in lettuce. The method yielded a linear calibration curve in the concentration ranges of 15-400 μg/kg for methyl parathion and 20-400 μg/kg for fenthion with correlation coefficients of above 0.9957. The limits of detection were 4.5 μg/kg for methyl parathion and 6.0 μg/kg for fenthion, respectively. The recoveries of methyl parathion and fenthion spiked in lettuce ranged from 96.0 to 104.2% with relative standard deviations less than 8.4%. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Preparation and evaluation of an adsorbent based on poly (muconic acid-co-divinylbenzene/ethylenedimethacrylate) for multiple monolithic fiber solid-phase microextraction of tetracycline antibiotics.

PubMed

Pei, Miao; Huang, Xiaojia

2017-09-29

To extract tetracycline antibiotics (TAs) effectively, a new adsorbent based on poly (muconic acid-co-divinylbenzene/ethylenedimethacrylate) monolith was fabricated and used as the extraction medium of multiple monolithic fiber solid-phase microextraction (MD/MF-SPME). The effect of the fabrication parameters on extraction efficiency was studied thoroughly. Elemental analysis, infrared spectroscopy, scanning electron microscopy and mercury intrusion porosimetry were used to check the physicochemical properties of the adsorbent. Some key parameters that affect the extraction performance of MD/MF-SPME for TAs were investigated systematically. Under the optimized experimental conditions, the prepared adsorbent could effectively extract the TAs through multiple interactions. At the same time, a simple and sensitive method for monitoring trace TAs in honey samples was developed by coupling MD/MF-SPME with high-performance liquid chromatography tandem mass spectrometry detection (MD/MF-SPME-HPLC-MS/MS). The limits of detection (S/N=3) for target compounds were in the range of 7.3-17.1ng/kg. The intra-day and inter-day precision (relative standard deviations, n=4, %) at 0.5μg/kg and 20.0μg/kg spiking concentrations were 5.0-9.5% and 3.6-10.0%, respectively. The mean recoveries of the target TAs in the real honey samples were between 70.5-111.0%. Copyright © 2017 Elsevier B.V. All rights reserved.

Mechanically stable, hierarchically porous Cu3(btc)2 (HKUST-1) monoliths via direct conversion of copper(II) hydroxide-based monoliths.

PubMed

Moitra, Nirmalya; Fukumoto, Shotaro; Reboul, Julien; Sumida, Kenji; Zhu, Yang; Nakanishi, Kazuki; Furukawa, Shuhei; Kitagawa, Susumu; Kanamori, Kazuyoshi

2015-02-28

The synthesis of highly crystalline macro-meso-microporous monolithic Cu3(btc)2 (HKUST-1; btc(3-) = benzene-1,3,5-tricarboxylate) is demonstrated by direct conversion of Cu(OH)2-based monoliths while preserving the characteristic macroporous structure. The high mechanical strength of the monoliths is promising for possible applications to continuous flow reactors.

Designing Catalytic Monoliths For Closed-Cycle CO2 Lasers

NASA Technical Reports Server (NTRS)

Guinn, Keith; Herz, Richard K.; Goldblum, Seth; Noskowski, ED

1992-01-01

LASCAT (Design of Catalytic Monoliths for Closed-Cycle Carbon Dioxide Lasers) computer program aids in design of catalyst in monolith by simulating effects of design decisions on performance of laser. Provides opportunity for designer to explore tradeoffs among activity and dimensions of catalyst, dimensions of monolith, pressure drop caused by flow of gas through monolith, conversion of oxygen, and other variables. Written in FORTRAN 77.

Chromatographic assessment of two hybrid monoliths prepared via epoxy-amine ring-opening polymerization and methacrylate-based free radical polymerization using methacrylate epoxy cyclosiloxane as functional monomer.

PubMed

Wang, Hongwei; Ou, Junjie; Lin, Hui; Liu, Zhongshan; Huang, Guang; Dong, Jing; Zou, Hanfa

2014-11-07

Two kinds of hybrid monolithic columns were prepared by using methacrylate epoxy cyclosiloxane (epoxy-MA) as functional monomer, containing three epoxy moieties and one methacrylate group. One column was in situ fabricated by ring-opening polymerization of epoxy-MA and 1,10-diaminodecane (DAD) using a porogenic system consisting of isopropanol (IPA), H2O and ethanol at 65°C for 12h. The other was prepared by free radical polymerization of epoxy-MA and ethylene dimethacrylate (EDMA) using 1-propanol and 1,4-butanediol as the porogenic solvents at 60°C for 12h. Two hybrid monoliths were investigated on the morphology and chromatographic assessment. Although two kinds of monolithic columns were prepared with epoxy-MA, their morphologies looked rather different. It could be found that the epoxy-MA-DAD monolith possessed higher column efficiencies (25,000-34,000plates/m) for the separation of alkylbenzenes than the epoxy-MA-EDMA monolith (12,000-13,000plates/m) in reversed-phase nano-liquid chromatography (nano-LC). Depending on the remaining epoxy or methacrylate groups on the surface of two pristine monoliths, the epoxy-MA-EDMA monolith could be easily modified with 1-octadecylamine (ODA) via ring-opening reaction, while the epoxy-MA-DAD monolith could be modified with stearyl methacrylate (SMA) via free radical reaction. The chromatographic performance for the separation of alkylbenzenes on SMA-modified epoxy-MA-DAD monolith was remarkably improved (42,000-54,000 plates/m) when compared with that on pristine epoxy-MA-DAD monolith, while it was not obviously enhanced on ODA-modified epoxy-MA-EDMA monolith when compared with that on pristine epoxy-MA-EDMA monolith. The enhancement of the column efficiency of epoxy-MA-DAD monolith after modification might be ascribed to the decreased mass-transfer resistence. The two kinds of hybrid monoliths were also applied for separations of six phenols and seven basic compounds in nano-LC. Copyright © 2014 Elsevier B.V. All rights reserved.

Steam reforming of n-hexane on pellet and monolithic catalyst beds. A comparative study on improvements due to heat transfer

NASA Technical Reports Server (NTRS)

1981-01-01

Monolithic catalysts with higher available active surface areas and better thermal conductivity than conventional pellets beds, making possible the steam reforming of fuels heavier than naphtha, were examined. Performance comparisons were made between conventional pellet beds and honeycomb monolith catalysts using n-hexane as the fuel. Metal-supported monoliths were examined. These offer higher structural stability and higher thermal conductivity than ceramic supports. Data from two metal monoliths of different nickel catalyst loadings were compared to pellets under the same operating conditions. Improved heat transfer and better conversion efficiencies were obtained with the monolith having higher catalyst loading. Surface-gas interaction was observed throughout the length of the monoliths.

Gravity or turbulence? IV. Collapsing cores in out-of-virial disguise

NASA Astrophysics Data System (ADS)

Ballesteros-Paredes, Javier; Vázquez-Semadeni, Enrique; Palau, Aina; Klessen, Ralf S.

2018-06-01

We study the dynamical state of massive cores by using a simple analytical model, an observational sample, and numerical simulations of collapsing massive cores. From the analytical model, we find that cores increase their column density and velocity dispersion as they collapse, resulting in a time evolution path in the Larson velocity dispersion-size diagram from large sizes and small velocity dispersions to small sizes and large velocity dispersions, while they tend to equipartition between gravity and kinetic energy. From the observational sample, we find that: (a) cores with substantially different column densities in the sample do not follow a Larson-like linewidth-size relation. Instead, cores with higher column densities tend to be located in the upper-left corner of the Larson velocity dispersion σv, 3D-size R diagram, a result explained in the hierarchical and chaotic collapse scenario. (b) Cores appear to have overvirial values. Finally, our numerical simulations reproduce the behavior predicted by the analytical model and depicted in the observational sample: collapsing cores evolve towards larger velocity dispersions and smaller sizes as they collapse and increase their column density. More importantly, however, they exhibit overvirial states. This apparent excess is due to the assumption that the gravitational energy is given by the energy of an isolated homogeneous sphere. However, such excess disappears when the gravitational energy is correctly calculated from the actual spatial mass distribution. We conclude that the observed energy budget of cores is consistent with their non-thermal motions being driven by their self-gravity and in the process of dynamical collapse.

The heart works against gravity

NASA Technical Reports Server (NTRS)

Seymour, R. S.; Hargens, A. R.; Pedley, T. J.

1993-01-01

The circulatory systems of vertebrate animals are closed, and blood leaves and returns to the heart at the same level. It is often concluded, therefore, that the heart works only against the viscous resistance of the system, not against gravity, even in vascular loops above the heart in which the siphon principle operates. However, we argue that the siphon principle does not assist blood flow in superior vascular loops if any of the descending vasculature is collapsible. If central arterial blood pressure is insufficient to support a blood column between the heart and the head, blood flow ceases because of vascular collapse. Furthermore, the siphon principle does not assist the heart even when a continuous stream of blood is flowing in a superior loop. The potential energy gained by blood as it is pumped to the head is lost to friction in partially collapsed descending vessels and thus is not regained. Application of the Poiseuille equation to flow in collapsible vessels is limited; resistance depends on flow rate in partially collapsed vessels with no transmural pressure difference, but flow rate is independent of resistance. Thus the pressure developed by the heart to establish a given flow rate is independent of the resistance occurring in the partially collapsed vessels. The pressure depends only on the height of the blood column and the resistance in the noncollapsed parts of the system. Simple laboratory models, involving water flow in collapsible tubing, dispel the idea that the siphon principle facilitates blood flow and suggest that previously published results may have been affected by experimental artifact.

Development and characterization of methacrylate-based hydrazide monoliths for oriented immobilization of antibodies.

PubMed

Brne, P; Lim, Y-P; Podgornik, A; Barut, M; Pihlar, B; Strancar, A

2009-03-27

Convective interaction media (CIM; BIA Separations) monoliths are attractive stationary phases for use in affinity chromatography because they enable fast affinity binding, which is a consequence of convectively enhanced mass transport. This work focuses on the development of novel CIM hydrazide (HZ) monoliths for the oriented immobilization of antibodies. Adipic acid dihydrazide (AADH) was covalently bound to CIM epoxy monoliths to gain hydrazide groups on the monolith surface. Two different antibodies were afterwards immobilized to hydrazide functionalized monolithic columns and prepared columns were tested for their selectivity. One column was further tested for the dynamic binding capacity.

Carbon-Based Honeycomb Monoliths for Environmental Gas-Phase Applications

PubMed Central

Moreno-Castilla, Carlos; Pérez-Cadenas, Agustín F.

2010-01-01

Honeycomb monoliths consist of a large number of parallel channels that provide high contact efficiencies between the monolith and gas flow streams. These structures are used as adsorbents or supports for catalysts when large gas volumes are treated, because they offer very low pressure drop, short diffusion lengths and no obstruction by particulate matter. Carbon-based honeycomb monoliths can be integral or carbon-coated ceramic monoliths, and they take advantage of the versatility of the surface area, pore texture and surface chemistry of carbon materials. Here, we review the preparation methods of these monoliths, their characteristics and environmental applications.

Collapse Mechanism Analysis in the Design of Superstructure Vehicle

NASA Astrophysics Data System (ADS)

Mohd Nor, M. K.

2016-11-01

The EU directive 2001/85/EC is an official European text which describes the specifications for “single deck class II and III vehicles” required to be approved by the regulation UN/ECE no.66 (R66). To prevent the catastrophic consequences by occupant during an accident, the Malaysian government has reinforced the same regulation upon superstructure construction. This paper discusses collapse mechanism analysis of a superstructure vehicle using a Crash D nonlinear analysis computer program based on this regulation. The analysis starts by hand calculation to define the required energy absorption by the chosen structure. Simple calculations were then performed to define the weakest collapse mechanism after undesirable collapse modes are eliminated. There are few factors highlighted in this work to pass the regulation. Using the selected cross section, Crash D simulation showed a good result. Generally, the deformation is linearly correlates to the energy absorption for the structure with low stiffness. Failure of critical members such as vertical lower side wall must be avoided to sustain safety of the passenger compartment and prevent from severe and fatal injuries to the trapped occupant.

Nonlinear analysis of collapse mechanism in superstructure vehicle

NASA Astrophysics Data System (ADS)

Nor, M. K. Mohd; Ho, C. S.; Ma'at, N.

2017-04-01

The EU directive 2001/85/EC is an official European text which describes the specifications for "single deck class II and III vehicles" required to be approved by the regulation UN/ECE no.66 (R66). To prevent the catastrophic consequences by occupant during an accident, the Malaysian government has reinforced the same regulation upon superstructure construction. This paper discusses collapse mechanism analysis of a superstructure vehicle using a Crash D nonlinear analysis computer program based on this regulation. The analysis starts by hand calculation to define the required energy absorption by the chosen structure. Simple calculations were then performed to define the weakest collapse mechanism after undesirable collapse modes are eliminated. There are few factors highlighted in this work to pass the regulation. Using the selected cross section, Crash D simulation showed a good result. Generally, the deformation is linearly correlates to the energy absorption for the structure with low stiffness. Failure of critical members such as vertical lower side wall must be avoided to sustain safety of the passenger compartment and prevent from severe and fatal injuries to the trapped occupant.

Collapse kinetics of vibrated granular chains

NASA Astrophysics Data System (ADS)

Jeng, Pei-Ren; Chen, Kuan Hua; Hwang, Gwo-jen; Lien, Chenhsin; To, Kiwing; Chou, Y. C.

2011-12-01

The kinetics of the collapse of the coil state into condensed states is studied with vibrated granular chain composed of N metal beads partially immersed in water. The radius of gyration of the chain, Rg is measured. For short chains (N < 140), disk-like condensed state is formed and Rg decreases with time such that the function ΔRg2 (≡ Rg2 - Rg2(∞)) = A e-t/τ, where the relaxation time τ follows a power-law dependence on the chain length N with an exponent γ = 1.9 ± 0.2. For the chains with length N ≥ 300, rod-like clusters are observed during the initial stage of collapse and Rg2 = Rg2(0) - Btβ, with β = 0.6 ± 0.1. In the coarsening stage, the exponential dependence of ΔRg2 on time still holds, however, the relaxation time τ fluctuates and has no simple dependence on N. Furthermore, the time dependence of the averaged radius of gyration of the individual clusters, Rg,cl can be described by the theory of Lifshitz and Slyozov. A peak in the structure function of long chains is observed in the initial stage of the collapse transition. The collapse transition in the bead chains is a first order phase transition. However, features of the spinodal decomposition are also observed.

Combined collapse by bridging and self-adhesion in a prototypical polymer model inspired by the bacterial nucleoid

NASA Astrophysics Data System (ADS)

Scolari, Vittore F.; Cosentino Lagomarsino, Marco

Recent experimental results suggest that the E. coli chromosome feels a self-attracting interaction of osmotic origin, and is condensed in foci by bridging interactions. Motivated by these findings, we explore a generic modeling framework combining solely these two ingredients, in order to characterize their joint effects. Specifically, we study a simple polymer physics computational model with weak ubiquitous short-ranged self attraction and stronger sparse bridging interactions. Combining theoretical arguments and simulations, we study the general phenomenology of polymer collapse induced by these dual contributions, in the case of regularly-spaced bridging. Our results distinguish a regime of classical Flory-like coil-globule collapse dictated by the interplay of excluded volume and attractive energy and a switch-like collapse where bridging interaction compete with entropy loss terms from the looped arms of a star-like rosette. Additionally, we show that bridging can induce stable compartmentalized domains. In these configurations, different "cores" of bridging proteins are kept separated by star-like polymer loops in an entropically favorable multi-domain configuration, with a mechanism that parallels micellar polysoaps. Such compartmentalized domains are stable, and do not need any intra-specific interactions driving their segregation. Domains can be stable also in presence of uniform attraction, as long as the uniform collapse is above its theta point.

Therapeutic CPAP Level Predicts Upper Airway Collapsibility in Patients With Obstructive Sleep Apnea.

PubMed

Landry, Shane A; Joosten, Simon A; Eckert, Danny J; Jordan, Amy S; Sands, Scott A; White, David P; Malhotra, Atul; Wellman, Andrew; Hamilton, Garun S; Edwards, Bradley A

2017-06-01

Upper airway collapsibility is a key determinant of obstructive sleep apnea (OSA) which can influence the efficacy of certain non-continuous positive airway pressure (CPAP) treatments for OSA. However, there is no simple way to measure this variable clinically. The present study aimed to develop a clinically implementable tool to evaluate the collapsibility of a patient's upper airway. Collapsibility, as characterized by the passive pharyngeal critical closing pressure (Pcrit), was measured in 46 patients with OSA. Associations were investigated between Pcrit and data extracted from patient history and routine polysomnography, including CPAP titration. Therapeutic CPAP level, demonstrated the strongest relationship to Pcrit (r2=0.51, p < .001) of all the variables investigated including apnea-hypopnea index, body mass index, sex, and age. Patients with a mildly collapsible upper airway (Pcrit ≤ -2 cmH2O) had a lower therapeutic CPAP level (6.2 ± 0.6 vs. 10.3 ± 0.4 cmH2O, p < .001) compared to patients with more severe collapsibility (Pcrit > -2 cmH2O). A therapeutic CPAP level ≤8.0 cmH2O was sensitive (89%) and specific (84%) for detecting a mildly collapsible upper airway. When applied to the independent validation data set (n = 74), this threshold maintained high specificity (91%) but reduced sensitivity (75%). Our data demonstrate that a patient's therapeutic CPAP requirement shares a strong predictive relationship with their Pcrit and may be used to accurately differentiate OSA patients with mild airway collapsibility from those with moderate-to-severe collapsibility. Although this relationship needs to be confirmed prospectively, our findings may provide clinicians with better understanding of an individual patient's OSA phenotype, which ultimately could assist in determining which patients are most likely to respond to non-CPAP therapies. © Sleep Research Society 2017. Published by Oxford University Press on behalf of the Sleep Research Society. All rights reserved. For permissions, please e-mail journals.permissions@oup.com.

Void Formation/Elimination and Viscoelastic Response of Polyphenylsilsesquioxane Monolith.

PubMed

Daiko, Yusuke; Oda, Yuki; Honda, Sawao; Iwamoto, Yuji

2018-05-19

Polyphenylsilsesquioxane (PhSiO 3/2 ) particles as an organic-inorganic hybrid were prepared using sol-gel method, and monolithic samples were obtained via a warm-pressing. The reaction mechanism of particles' polymerization and transformation to the monolith under the warm-press were investigated using solid state 29 Si nuclear magnetic resonance (NMR) spectrometer, thermal gravimetric-differential thermal analyzer (TG-DTA), mass spectrometer (MS) and scanning electron microscope (SEM). Transparent and void-free monoliths are successfully obtained by warm-pressing above 180 °C. Both the terminal ⁻OH groups on particles' surface and warm-pressing are necessary for preparation of void-free PhSiO 3/2 monolith. From the load-displacement measurement at various temperatures, a viscoelastic deformation is seen for PhSiO 3/2 monolith with voids. On the other hand, an elastic deformation is seen for void-free PhSiO 3/2 monolith, and the void-free monolith shows much higher breakdown voltage.

Estimating explosion properties of normal hydrogen-rich core-collapse supernovae

NASA Astrophysics Data System (ADS)

Pejcha, Ondrej

2017-08-01

Recent parameterized 1D explosion models of hundreds of core-collapse supernova progenitors suggest that success and failure are intertwined in a complex pattern that is not a simple function of the progenitor initial mass. This rugged landscape is present also in other explosion properties, allowing for quantitative tests of the neutrino mechanism from observations of hundreds of supernovae discovered every year. We present a new self-consistent and versatile method that derives photospheric radius and temperature variations of normal hydrogen-rich core-collapse supernovae based on their photometric measurements and expansion velocities. We construct SED and bolometric light curves, determine explosion energies, ejecta and nickel masses while taking into account all uncertainties and covariances of the model. We describe the efforts to compare the inferences to the predictions of the neutrino mechanim. The model can be adapted to include more physical assumptions to utilize primarily photometric data coming from surveys such as LSST.

Consolidation and densification methods for fibrous monolith processing

DOEpatents

Sutaria, Manish P.; Rigali, Mark J.; Cipriani, Ronald A.; Artz, Gregory J.; Mulligan, Anthony C.

2006-06-20

Methods for consolidation and densification of fibrous monolith composite structures are provided. Consolidation and densification of two- and three-dimensional fibrous monolith components having complex geometries can be achieved by pressureless sintering. The fibrous monolith composites are formed from filaments having at least a first material composition generally surrounded by a second material composition. The composites are sintered at a pressure of no more than about 30 psi to provide consolidated and densified fibrous monolith composites.

CO2 adsorption on modified carbon coated monolith: effect of surface modification by using alkaline solutions

NASA Astrophysics Data System (ADS)

Hosseini, Soraya; Marahel, Ehsan; Bayesti, Iman; Abbasi, Ali; Chuah Abdullah, L.; Choong, Thomas S. Y.

2015-01-01

A monolithic column was used to study the feasibility of modified carbon-coated monolith for recovery of CO2 from gaseous mixtures (He/CO2) in a variety of operating conditions. Carbon-coated monolith was prepared by dip-coating method and modified by two alkaline solutions, i.e. NH3 and KOH. The surface properties of the carbon-coated monolith were altered by functional groups via KOH and NH3 treatments. The comparative study of CO2 uptake by two different adsorbents, i.e. unmodified and modified carbon-coated monolith, demonstrated that the applied modification process had improved CO2 adsorption. The presence of nitrogen- and oxygen-containing functional groups on the surface of the carbon led to an improved level of microporosity on the synthesized carbon-coated monolith. The physical parameters such as higher surface area, lower pore diameter, and larger micropore volume of modified monoliths indicated direct influence on the adsorbed amount of CO2. In the present study, the Deactivation Model is applied to analyze the breakthrough curves. The adsorption capacity increased with an increase in pressure and concentration, while a reduction of CO2 adsorption capacity was occurred with increase in temperature. Ammonia (NH3) and potassium hydroxide (KOH)-modified carbon-coated monolith showed an increase of approximately 12 and 27% in CO2 adsorption, respectively, as compared to unmodified carbon-coated monolith.

Preparation and evaluation of a macroporous molecularly imprinted hybrid silica monolithic column for recognition of proteins by high performance liquid chromatography.

PubMed

Lin, Zian; Yang, Fan; He, Xiwen; Zhao, Xiaomiao; Zhang, Yukui

2009-12-04

A novel type of macroporous molecularly imprinted hybrid silica monolithic column was first developed for recognition of proteins. The macroporous silica-based monolithic skeleton was synthesized in a 4.6mm i.d. stainless steel column by a mild sol-gel process with methyltrimethoxysilane (MTMS) as a sole precursor, and then vinyl groups were introduced onto the surface of the silica skeleton by chemical modification of gamma-methacryloxypropyltrimethoxysilane (gamma-MAPS). Subsequently, the molecularly imprinted polymer (MIP) coating was copolymerized and anchored onto the surface of the silica monolith. Bovine serum albumin (BSA) and lysozyme (Lyz), which differ greatly in molecular size, isoelectric point, and charge, were representatively selected for imprinted templates to evaluate recognition property of the hybrid silica-based MIP monolith. Some important factors, such as template-monomer molar ratio, total monomer concentration and crosslinking density, were systematically investigated. Under the optimum conditions, the obtained hybrid silica-based MIP monolith showed higher binding affinity for template than its corresponding non-imprinted (NIP) monolith. The imprinted factor (IF) for BSA and Lyz reached 9.07 and 6.52, respectively. Moreover, the hybrid silica-based MIP monolith displayed favorable binding characteristics for template over competitive protein. Compared with the imprinted silica beads for stationary phase and in situ organic polymer-based hydrogel MIP monolith, the hybrid silica MIP monolith exhibited higher recognition, stability and lifetime.

Interferometrically enhanced sub-terahertz picosecond imaging utilizing a miniature collapsing-field-domain source

NASA Astrophysics Data System (ADS)

Vainshtein, Sergey N.; Duan, Guoyong; Mikhnev, Valeri A.; Zemlyakov, Valery E.; Egorkin, Vladimir I.; Kalyuzhnyy, Nikolay A.; Maleev, Nikolai A.; Näpänkangas, Juha; Sequeiros, Roberto Blanco; Kostamovaara, Juha T.

2018-05-01

Progress in terahertz spectroscopy and imaging is mostly associated with femtosecond laser-driven systems, while solid-state sources, mainly sub-millimetre integrated circuits, are still in an early development phase. As simple and cost-efficient an emitter as a Gunn oscillator could cause a breakthrough in the field, provided its frequency limitations could be overcome. Proposed here is an application of the recently discovered collapsing field domains effect that permits sub-THz oscillations in sub-micron semiconductor layers thanks to nanometer-scale powerfully ionizing domains arising due to negative differential mobility in extreme fields. This shifts the frequency limit by an order of magnitude relative to the conventional Gunn effect. Our first miniature picosecond pulsed sources cover the 100-200 GHz band and promise milliwatts up to ˜500 GHz. Thanks to the method of interferometrically enhanced time-domain imaging proposed here and the low single-shot jitter of ˜1 ps, our simple imaging system provides sufficient time-domain imaging contrast for fresh-tissue terahertz histology.

Modeling sound transmission and reflection in the pulmonary system and chest with application to diagnosis of a collapsed lung

NASA Astrophysics Data System (ADS)

Royston, Thomas J.; Zhang, Xiangling; Mansy, Hussein A.; Sandler, Richard H.

2002-05-01

Experimental studies have shown that a pneumothorax (collapsed lung) substantially alters the propagation of sound introduced at the mouth of an intubated subject and measured at the chest surface. Thus, it is hypothesized that an inexpensive diagnostic procedure could be developed for detection of a pneumothorax based on a simple acoustic test. In the present study, theoretical models of sound transmission through the pulmonary system and chest region are reviewed in the context of their ability to predict acoustic changes caused by a pneumothorax, as well as other pathologic conditions. Such models could aid in parametric design studies to develop acoustic means of diagnosing pneumothorax and other lung pathologies. Extensions of previously developed simple models of the authors are presented that are in more quantitative agreement with experimental results and that simulate both transmission from the bronchial airways to the chest wall, as well as reflection in the bronchial airways. [Research supported by NIH NCRR Grant No. 14250 and NIH NHLBI Grant No. 61108.

Monolithic carbon structures including suspended single nanowires and nanomeshes as a sensor platform

PubMed Central

2013-01-01

With the development of nanomaterial-based nanodevices, it became inevitable to develop cost-effective and simple nanofabrication technologies enabling the formation of nanomaterial assembly in a controllable manner. Herein, we present suspended monolithic carbon single nanowires and nanomeshes bridging two bulk carbon posts, fabricated in a designed manner using two successive UV exposure steps and a single pyrolysis step. The pyrolysis step is accompanied with a significant volume reduction, resulting in the shrinkage of micro-sized photoresist structures into nanoscale carbon structures. Even with the significant elongation of the suspended carbon nanowire induced by the volume reduction of the bulk carbon posts, the resultant tensional stress along the nanowire is not significant but grows along the wire thickness; this tensional stress gradient and the bent supports of the bridge-like carbon nanowire enhance structural robustness and alleviate the stiction problem that suspended nanostructures frequently experience. The feasibility of the suspended carbon nanostructures as a sensor platform was demonstrated by testing its electrochemical behavior, conductivity-temperature relationship, and hydrogen gas sensing capability. PMID:24256942

Monolithic integration of hybrid perovskite single crystals with heterogenous substrate for highly sensitive X-ray imaging

NASA Astrophysics Data System (ADS)

Wei, Wei; Zhang, Yang; Xu, Qiang; Wei, Haotong; Fang, Yanjun; Wang, Qi; Deng, Yehao; Li, Tao; Gruverman, Alexei; Cao, Lei; Huang, Jinsong

2017-04-01

The monolithic integration of new optoelectronic materials with well-established inexpensive silicon circuitry is leading to new applications, functionality and simple readouts. Here, we show that single crystals of hybrid perovskites can be integrated onto virtually any substrates, including silicon wafers, through facile, low-temperature, solution-processed molecular bonding. The brominated (3-aminopropyl)triethoxysilane molecule binds the native oxide of silicon and participates in the perovskite crystal with its ammonium bromide group, yielding a solid mechanical and electrical connection. The dipole of the bonding molecule reduces device noise while retaining signal intensity. The reduction of dark current enables the detectors to be operated at increased bias, resulting in a sensitivity of 2.1 × 104 µC Gyair-1 cm-2 under 8 keV X-ray radiation, which is over a thousand times higher than the sensitivity of amorphous selenium detectors. X-ray imaging with both perovskite pixel detectors and linear array detectors reduces the total dose by 15-120-fold compared with state-of-the-art X-ray imaging systems.

Lateral photovoltaic effect in flexible free-standing reduced graphene oxide film for self-powered position-sensitive detection

PubMed Central

Moon, In Kyu; Ki, Bugeun; Yoon, Seonno; Oh, Jungwoo

2016-01-01

Lightweight, simple and flexible self-powered photodetectors are urgently required for the development and application of advanced optical systems for the future of wearable electronic technology. Here, using a low-temperature reduction process, we report a chemical approach for producing freestanding monolithic reduced graphene oxide papers with different gradients of the carbon/oxygen concentration ratio. We also demonstrate a novel type of freestanding monolithic reduced graphene oxide self-powered photodetector based on a symmetrical metal–semiconductor–metal structure. Upon illumination by a 633-nm continuous wave laser, the lateral photovoltage is observed to vary linfearly with the laser position between two electrodes on the reduced graphene oxide surface. This result may suggest that the lateral photovoltaic effect in the reduced graphene oxide film originates from the built-in electric field by the combination of both the photothermal electric effect and the gradient of the oxygen-to-carbon composition. These results represent substantial progress toward novel, chemically synthesized graphene-based photosensors and suggest one-step integration of graphene-based optoelectronics in the future. PMID:27634110

In situ synthesis of metal-organic frameworks in a porous polymer monolith as the stationary phase for capillary liquid chromatography.

PubMed

Yang, Shengchao; Ye, Fanggui; Zhang, Cong; Shen, Shufen; Zhao, Shulin

2015-04-21

In this study, HKUST-1 was synthesized in situ on the porous polymer monolith as the stationary phase for capillary liquid chromatography (cLC). The unique carboxyl functionalized poly(methacrylic acid-co-ethylene dimethacrylate) (poly(MAA-co-EDMA)) monolith was used as a support to directly grow HKUST-1 by a controlled layer-by-layer self-assembly strategy. X-ray diffraction, scanning electron microscopy, energy dispersive X-ray spectrometry, and Fourier transform infrared spectroscopy of the resulting HKUST-1-poly(MAA-co-EDMA) monoliths indicated that HKUST-1 was successfully grafted onto the pore surface of the poly(MAA-co-EDMA) monolith. The column performance of HKUST-1-poly(MAA-co-EDMA) monoliths for the separation of various small molecules, such as benzenediols, xylenes, ethylbenzenes, and styrenes, was evaluated. The chromatographic performance was found to improve with increasing HKUST-1 density, and the column efficiencies and resolutions of HKUST-1-poly(MAA-co-EDMA) monoliths were 18 320-19 890 plates m(-1) and 1.62-6.42, respectively, for benzenediols. The HKUST-1-poly(MAA-co-EDMA) monolith displayed enhanced resolution for the separation of positional isomers when compared to the traditional C18 and HKUST-1 incorporated polymer monoliths. Hydrophobic, π-π, and hydrogen bonding interactions within the HKUST-1-poly(MAA-co-EDMA) monolith were observed in the separation of small molecules. The results showed that the HKUST-1-poly(MAA-co-EDMA) monoliths are promising stationary phases for cLC.

Synthesis of ordered mesoporous carbon monoliths with bicontinuous cubic pore structure of Ia3d symmetry.

PubMed

Yang, Haifeng; Shi, Qihui; Liu, Xiaoying; Xie, Songhai; Jiang, Decheng; Zhang, Fuqiang; Yu, Chengzhong; Tu, Bo; Zhao, Dongyuan

2002-12-07

Large-diameter-sized mesoporous carbon monoliths with bicontinuous cubic structure of Ia3d symmetry have been synthesized by using mesoporous silica monoliths as hard templates; such carbon monoliths show potential application of advanced electrodes and electrochemical double layer capacitors.

Consolidation and densification methods for fibrous monolith processing

DOEpatents

Sutaria, Manish P.; Rigali, Mark J.; Cipriani, Ronald A.; Artz, Gregory J.; Mulligan, Anthony C.

2004-05-25

Methods for consolidation and densification of fibrous monolith composite structures are provided. Consolidation and densification of two- and three-dimensional fibrous monolith components having complex geometries can be achieved by pressureless sintering. The fibrous monolith composites are formed from filaments having at least a first material composition generally surrounded by a second material composition. The composites are sintered in an inert gas or nitrogen gas at a pressure of no more than about 30 psi to provide consolidated and densified fibrous monolith composites.

Gas storage carbon with enhanced thermal conductivity

DOEpatents

Burchell, Timothy D.; Rogers, Michael Ray; Judkins, Roddie R.

2000-01-01

A carbon fiber carbon matrix hybrid adsorbent monolith with enhanced thermal conductivity for storing and releasing gas through adsorption and desorption is disclosed. The heat of adsorption of the gas species being adsorbed is sufficiently large to cause hybrid monolith heating during adsorption and hybrid monolith cooling during desorption which significantly reduces the storage capacity of the hybrid monolith, or efficiency and economics of a gas separation process. The extent of this phenomenon depends, to a large extent, on the thermal conductivity of the adsorbent hybrid monolith. This invention is a hybrid version of a carbon fiber monolith, which offers significant enhancements to thermal conductivity and potential for improved gas separation and storage systems.

Martian tension fractures and the formation of grabens and collapse features at Valles Marineris

NASA Technical Reports Server (NTRS)

Tanaka, K. L.; Golombek, M. P.

1989-01-01

Simple models of the Martian crust are summarized that predict extensional deformation style on the basis of depth, material friction and strength, and hydraulic conditions appropriate to the planet. These models indicate that tension fractures may be common features on Mars, given adequate differential stress conditions. Examples of tension fractures on Mars inferred from morphological criteria are examined based on the probable geologic conditions in which they formed and on model constraints. It is proposed that the grabens and collapse features of Valles Marineris are controlled by tension fractures in intact basement rocks that lie below impact ejecta.

Basic processes and factors determining the evolution of collapse sinkholes: a sensitivity study

NASA Astrophysics Data System (ADS)

Romanov, Douchko; Kaufmann, Georg

2017-04-01

Collapse sinkholes appear as closed depressions at the surface. The origin of these karst features is related to the continuous dissolution of the soluble rock caused by a focussed sub-surface flow. Water flowing along a preferential pathway through fissures and fractures within the phreatic part of a karst aquifer is able to dissolve the rock (limestone, gypsum, anhydrite). With time, the dissolved void volume increases and part of the ceiling above the stream can become unstable, collapses, and accumulates as debris in the flow path. The debris partially blocks the flow and thus activates new pathways. Because of the low compaction of the debris (high hydraulic conductivity), the flow and the dissolution rates within this crushed zone remain high. This allows a relatively fast dissolutional and erosional removal of the crushed material and the development of new empty voids. The void volume expands upwards towards the surface until a collapse sinkhole is formed. The collapse sinkholes exhibit a large variety of shapes (cylindrical, cone-, bowl-shaped), depths (from few to few hundred meters) and diameters (meters up to hundreds of meters). Two major processes are responsible for this diversity: a) the karst evolution of the aquifer - responsible for the dissolutional and erosional removal of material; b) the mechanical evolution of the host rock and the existence of structural features, faults for example, which determine the stability and the magnitude of the subsequent collapses. In this work we demonstrate the influence of the host rock type, the hydrological and geological boundary conditions, the chemical composition of the flowing water, and the geometry and the scale of the crushed zone, on the location and the evolution of the growing sinkhole. We demonstrate the ability of the karst evolution models to explain, at least qualitatively, the growth and the morphology of the collapse sinkholes and to roughly predict their shape and location. Implementing simple rules that describe the mechanical collapse, we come to the conclusion that a complete quantitative and qualitative description of a collapse sinkhole is possible, but for this it is necessary to take into account also the mechanical properties of the rock and the processes determining the mechanics of the collapses.

An inorganic boronate affinity in-needle monolithic device for specific capture of cis-diol containing compounds.

PubMed

Jin, Shanxia; Zhang, Wei; Yang, Qin; Dai, Lili; Zhou, Ping

2018-02-01

In this work, inorganic boronate affinity monolith was prepared by in situ synthesis in 0.33mm i.d. stainless steel needle through sol-gel process using tetraethoxysilane and tetrabutyl orthotitanate as the co-precursors. The morphology, structure and composition of the monolith were characterized. In contrast to conventional boronate affinity materials, inorganic boric acid was used as affinity ligand. Different compounds were used for the evaluation of the boronate affinity of this inorganic monolithic material. The monolith exhibited good selectivity towards cis-diol containing compounds. Recovery of greater than 90% was achieved for in-needle extraction of catechol under neutral conditions. Owing to the hydrophilic property of the monolith, the procedure of affinity chromatography could be performed in aqueous solution. This monolithic in-needle device will be useful for boronate affinity extraction of small-volume samples. Copyright © 2017 Elsevier B.V. All rights reserved.

Zeolitic imidazolate framework-methacrylate composite monolith characterization by inverse gas chromatography.

PubMed

Yusuf, Kareem; Badjah-Hadj-Ahmed, Ahmed Yacine; Aqel, Ahmad; Aouak, Taieb; ALOthman, Zeid Abdullah

2016-04-22

Thermodynamic characterization of butyl methacrylate-co-ethylene dimethacrylate neat monolith and zeolitic imidazolate framework-8 incorporated with butyl methacrylate-co-ethylene dimethacrylate composite monolith were studied using inverse gas chromatography at infinite dilution under 1MPa column pressure and various column temperatures. The free energy of adsorption (ΔGA), enthalpy of adsorption (ΔHA) and entropy of adsorption (ΔSA) were determined using a series of n-alkanes. The dispersive component of surface energy (γS(D)) was estimated by Dorris-Gray and Schultz et al. The composite monolith showed a more energetic surface than the neat monolith. The acidic, KA, and basic, KD, parameters for both materials were estimated using a group of polar probes. A basic character was concluded with more basic behavior for the neat monolith. Flory-Huggins parameter, χ, was taken as a measure of miscibility between the probes with the low molecular weight and the high molecular weight monolith. Inverse gas chromatography provides a better understanding of the role of incorporated zeolitic imidazolate framework (ZIF-8) into the polymer matrix in its monolithic form. Copyright © 2016 Elsevier B.V. All rights reserved.

One-pot preparation of a sulfamethoxazole functionalized affinity monolithic column for selective isolation and purification of trypsin.

PubMed

Xiao, Yuan; Guo, Jialiang; Ran, Danni; Duan, Qianqian; Crommen, Jacques; Jiang, Zhengjin

2015-06-26

A facile and efficient "one-pot" copolymerization strategy was used for the preparation of sulfonamide drug (SA) functionalized monolithic columns. Two novel SA-immobilized methacrylate monolithic columns, i.e. poly(GMA-SMX-co-EDMA) and poly(GMA-SAA-co-EDMA) were prepared by one-pot in situ copolymerization of the drug ligand (sulfamethoxazole (SMX) or sulfanilamide (SAA)), the monomer (glycidyl methacrylate, GMA) and the cross-linker (ethylene dimethacrylate, EDMA) within 100 μm i.d. capillaries under optimized polymerization conditions. The physicochemical properties and column performance of the fabricated monolithic columns were characterized by elemental analysis, scanning electron microscopy and micro-HPLC. Satisfactory column permeability, efficiency and separation performance were obtained on the optimized poly(GMA-SMX-co-EDMA) monolithic column for small molecules, such as a standard test mixture and eight aromatic ketones. Notably, it was found that the poly(GMA-SMX-co-EDMA) monolith showed a selective affinity to trypsin, while the poly(GMA-SAA-co-EDMA) monolith containing sulfanilamide did not exhibit such affinity at all. This research not only provides a novel monolith for the selective isolation and purification of trypsin, but it also offers the possibility to easily prepare novel drug functionalized methacrylate monoliths through a one-pot copolymerization strategy. Copyright © 2015 Elsevier B.V. All rights reserved.

Green synthesis of mesoporous molecular sieve incorporated monoliths using room temperature ionic liquid and deep eutectic solvents.

PubMed

Zhang, Li-Shun; Zhao, Qing-Li; Li, Xin-Xin; Li, Xi-Xi; Huang, Yan-Ping; Liu, Zhao-Sheng

2016-12-01

A hybrid monolith incorporated with mesoporous molecular sieve MCM-41 of uniform pore structure and high surface area was prepared with binary green porogens in the first time. With a mixture of room temperature ionic liquids and deep eutectic solvents as porogens, MCM-41 was modified with 3-(trimethoxysilyl) propyl methacrylate (γ-MPS) and the resulting MCM-41-MPS was incorporated into poly (BMA-co-EDMA) monoliths covalently. Because of good dispersibility of MCM-41-MPS in the green solvent-based polymerization system, high permeability and homogeneity for the resultant hybrid monolithic columns was achieved. The MCM-41-MPS grafted monolith was characterized by scanning electron microscopy, energy dispersive spectrometer area scanning, transmission electron microscopy, FT-IR spectra and nitrogen adsorption tests. Chromatographic performance of MCM-41-MPS grafted monolith was characterized by separating small molecules in capillary electrochromatography, including phenol series, naphthyl substitutes, aniline series and alkyl benzenes. The maximum column efficiency of MCM-41-MPS grafted monolith reached 209,000 plates/m, which was twice higher than the corresponding MCM-41-MPS free monolith. Moreover, successful separation of non-steroidal anti-inflammatory drugs and polycyclic aromatic hydrocarbons demonstrated the capacity in broad-spectrum application of the MCM-41-MPS incorporated monolith. The results indicated that green synthesis using room temperature ionic liquid and deep eutectic solvents is an effective method to prepare molecular sieve-incorporated monolithic column. Copyright © 2016 Elsevier B.V. All rights reserved.

Hydrogel coated monoliths for enzymatic hydrolysis of penicillin G

PubMed Central

Smeltink, M. W.; Straathof, A. J. J.; Paasman, M. A.; van de Sandt, E. J. A. X.; Kapteijn, F.; Moulijn, J. A.

2008-01-01

The objective of this work was to develop a hydrogel-coated monolith for the entrapment of penicillin G acylase (E. coli, PGA). After screening of different hydrogels, chitosan was chosen as the carrier material for the preparation of monolithic biocatalysts. This protocol leads to active immobilized biocatalysts for the enzymatic hydrolysis of penicillin G (PenG). The monolithic biocatalyst was tested in a monolith loop reactor (MLR) and compared with conventional reactor systems using free PGA, and a commercially available immobilized PGA. The optimal immobilization protocol was found to be 5 g l−1 PGA, 1% chitosan, 1.1% glutaraldehyde and pH 7. Final PGA loading on glass plates was 29 mg ml−1 gel. For 400 cpsi monoliths, the final PGA loading on functionalized monoliths was 36 mg ml−1 gel. The observed volumetric reaction rate in the MLR was 0.79 mol s−1 m−3monolith. Apart from an initial drop in activity due to wash out of PGA at higher ionic strength, no decrease in activity was observed after five subsequent activity test runs. The storage stability of the biocatalysts is at least a month without loss of activity. Although the monolithic biocatalyst as used in the MLR is still outperformed by the current industrial catalyst (immobilized preparation of PGA, 4.5 mol s−1 m−3catalyst), the rate per gel volume is slightly higher for monolithic catalysts. Good activity and improved mechanical strength make the monolithic bioreactor an interesting alternative that deserves further investigation for this application. Although moderate internal diffusion limitations have been observed inside the gel beads and in the gel layer on the monolith channel, this is not the main reason for the large differences in reactor performance that were observed. The pH drop over the reactor as a result of the chosen method for pH control results in a decreased performance of both the MLR and the packed bed reactor compared to the batch system. A different reactor configuration including an optimal pH profile is required to increase the reactor performance. The monolithic stirrer reactor would be an interesting alternative to improve the performance of the monolith-PGA combination. PMID:18427849

Multiple monolithic fiber solid-phase microextraction based on a polymeric ionic liquid with high-performance liquid chromatography for the determination of steroid sex hormones in water and urine.

PubMed

Liao, Keren; Mei, Meng; Li, Haonan; Huang, Xiaojia; Wu, Cuiqin

2016-02-01

The development of a simple and sensitive analytical approach that combines multiple monolithic fiber solid-phase microextraction with liquid desorption followed by high-performance liquid chromatography with diode array detection is proposed for the determination of trace levels of seven steroid sex hormones (estriol, 17β-estradiol, testosterone, ethinylestradiol, estrone, progesterone and mestranol) in water and urine matrices. To extract the target analytes effectively, multiple monolithic fiber solid-phase microextraction based on a polymeric ionic liquid was used to concentrate hormones. Several key extraction parameters including desorption solvent, extraction and desorption time, pH value and ionic strength in sample matrix were investigated in detail. Under the optimal experimental conditions, the limits of detection were found to be in the range of 0.027-0.12 μg/L. The linear range was 0.10-200 μg/L for 17β-estradiol, 0.25-200 μg/L estriol, ethinylestradiol and estrone, and 0.50-200 μg/L for the other hormones. Satisfactory linearities were achieved for analytes with the correlation coefficients above 0.99. Acceptable method reproducibility was achieved by evaluating the repeatability and intermediate precision with relative standard deviations of both less than 8%. The enrichment factors ranged from 54- to 74-fold. Finally, the proposed method was successfully applied to the analysis of steroid sex hormones in environmental water samples and human urines with spiking recoveries ranged from 75.6 to 116%. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Automatic and integrated micro-enzyme assay (AIμEA) platform for highly sensitive thrombin analysis via an engineered fluorescence protein-functionalized monolithic capillary column.

PubMed

Lin, Lihua; Liu, Shengquan; Nie, Zhou; Chen, Yingzhuang; Lei, Chunyang; Wang, Zhen; Yin, Chao; Hu, Huiping; Huang, Yan; Yao, Shouzhuo

2015-04-21

Nowadays, large-scale screening for enzyme discovery, engineering, and drug discovery processes require simple, fast, and sensitive enzyme activity assay platforms with high integration and potential for high-throughput detection. Herein, a novel automatic and integrated micro-enzyme assay (AIμEA) platform was proposed based on a unique microreaction system fabricated by a engineered green fluorescence protein (GFP)-functionalized monolithic capillary column, with thrombin as an example. The recombinant GFP probe was rationally engineered to possess a His-tag and a substrate sequence of thrombin, which enable it to be immobilized on the monolith via metal affinity binding, and to be released after thrombin digestion. Combined with capillary electrophoresis-laser-induced fluorescence (CE-LIF), all the procedures, including thrombin injection, online enzymatic digestion in the microreaction system, and label-free detection of the released GFP, were integrated in a single electrophoretic process. By taking advantage of the ultrahigh loading capacity of the AIμEA platform and the CE automatic programming setup, one microreaction column was sufficient for many times digestion without replacement. The novel microreaction system showed significantly enhanced catalytic efficiency, about 30 fold higher than that of the equivalent bulk reaction. Accordingly, the AIμEA platform was highly sensitive with a limit of detection down to 1 pM of thrombin. Moreover, the AIμEA platform was robust and reliable to detect thrombin in human serum samples and its inhibition by hirudin. Hence, this AIμEA platform exhibits great potential for high-throughput analysis in future biological application, disease diagnostics, and drug screening.

Analyses of sulfonamide antibiotics in meat samples by on-line concentration capillary electrochromatography-mass spectrometry.

PubMed

Cheng, Yi-Jie; Huang, Sing-Hao; Singco, Brenda; Huang, Hsi-Ya

2011-10-21

In this work, a series of poly(divinylbenzene-alkyl methacrylate) monolithic stationary phases, which were prepared by single step in situ polymerization of divinylbenzene and various alkyl methacrylates (butyl-, octyl-, lauryl- or stearyl methacrylate), were developed as separation columns of nine common sulfonamide antibiotics for capillary electrochromatography (CEC) coupled to mass spectrometry (MS). Results indicated that the sulfonamide's retention became weak with increased carbon chain length of alkyl methacrylate monomer (for example, t(R)=68 min and 21 min for butyl- and lauryl methacrylate, respectively). Among them, the poly(divinylbenzene-octyl methacrylate) (poly(DVB-OMA)) monolith was regarded as the optimal separation column as this provided better resolution within the shortest retention time. Moreover, the cross-sectional roughness of the monolithic column-end, that was used to couple to the ESI interface, strongly influenced the electrospray stability in the CEC-MS. Before the column was connected to the ESI-MS, a simple polishing was done to reduce the roughness of the column end that resulted to a great improvement in the signal stability. The relative standard deviations (RSDs) of the peak areas for the unpolished and polished ends of the poly(DVB-OMA) columns (n=5) were in the range of 46.1-60.2% and 8.9-16.4%, respectively. Furthermore, optimization of the mobile phase composition and the gradient elution strategy successfully determined the sulfonamide antibiotics in meat samples with as low as 10 μg/L level. Copyright © 2011 Elsevier B.V. All rights reserved.

Synthesis of Porous Carbon Monoliths Using Hard Templates.

PubMed

Klepel, Olaf; Danneberg, Nina; Dräger, Matti; Erlitz, Marcel; Taubert, Michael

2016-03-21

The preparation of porous carbon monoliths with a defined shape via template-assisted routes is reported. Monoliths made from porous concrete and zeolite were each used as the template. The porous concrete-derived carbon monoliths exhibited high gravimetric specific surface areas up to 2000 m²·g -1 . The pore system comprised macro-, meso-, and micropores. These pores were hierarchically arranged. The pore system was created by the complex interplay of the actions of both the template and the activating agent as well. On the other hand, zeolite-made template shapes allowed for the preparation of microporous carbon monoliths with a high volumetric specific surface area. This feature could be beneficial if carbon monoliths must be integrated into technical systems under space-limited conditions.

Synthesis of Porous Carbon Monoliths Using Hard Templates

PubMed Central

Klepel, Olaf; Danneberg, Nina; Dräger, Matti; Erlitz, Marcel; Taubert, Michael

2016-01-01

The preparation of porous carbon monoliths with a defined shape via template-assisted routes is reported. Monoliths made from porous concrete and zeolite were each used as the template. The porous concrete-derived carbon monoliths exhibited high gravimetric specific surface areas up to 2000 m2·g−1. The pore system comprised macro-, meso-, and micropores. These pores were hierarchically arranged. The pore system was created by the complex interplay of the actions of both the template and the activating agent as well. On the other hand, zeolite-made template shapes allowed for the preparation of microporous carbon monoliths with a high volumetric specific surface area. This feature could be beneficial if carbon monoliths must be integrated into technical systems under space-limited conditions. PMID:28773338

Fernandina caldera collapse morphology in geometric and dynamic comparison to sandbox models, subsidence sinks over nuclear-explosion cavities, and some other calderas

NASA Astrophysics Data System (ADS)

Howard, K. A.

2009-12-01

The 1968 collapse structure of Fernandina caldera (1.5 km3 collapsed) and also the smaller Darwin Bay caldera in Galápagos each closely resembles morphologically the structural zoning of features found in depressions collapsed into nuclear-explosion cavities (“sinks” of Houser, 1969) and in coherent sandbox-collapse models. Coherent collapses characterized by faulting, folding, and organized structure contrast with spalled pit craters (and lab experiments with collapsed powder) where disorganized piles of floor rubble result from tensile failure of the roof. Subsidence in coherent mode, whether in weak sand in the lab, stronger desert alluvium for nuclear-test sinks, or in hard rock for calderas, exhibits consistent morphologic zones. Characteristically in the sandbox and the nuclear-test analogs these include a first-formed central plug that drops along annular reverse faults. This plug and a surrounding inward-tilted or monoclinal ring (hanging wall of the reverse fault) contract as the structure expands outward by normal faulting, wherein peripheral rings of distending material widen the upper part of the structure along inward-dipping normal faults and compress inner zones and help keep them intact. In Fernandina, a region between the monocline and the outer zone of normal faulting is interpreted, by comparison to the analogs, to overlie the deflation margin of an underlying magma chamber. The same zoning pattern is recognized in structures ranging from sandbox subsidence features centimeters across, to Alae lave lake and nuclear-test sinks tens to hundreds of meters across, to Fenandina’s 2x4 km-wide collapse, to Martian calderas tens of kilometers across. Simple dimensional analysis using the height of cliffs as a proxie for material strength implies that the geometric analogs are good dynamic analogs, and validates that the pattern of both reverse and normal faulting that has been reported consistently from sandbox modeling applies widely to calderas.

Estimating the effect of lung collapse and pulmonary shunt on gas exchange during breath-hold diving: the Scholander and Kooyman legacy.

PubMed

Fahlman, A; Hooker, S K; Olszowka, A; Bostrom, B L; Jones, D R

2009-01-01

We developed a mathematical model to investigate the effect of lung compression and collapse (pulmonary shunt) on the uptake and removal of O(2), CO(2) and N(2) in blood and tissue of breath-hold diving mammals. We investigated the consequences of pressure (diving depth) and respiratory volume on pulmonary shunt and gas exchange as pressure compressed the alveoli. The model showed good agreement with previous studies of measured arterial O(2) tensions (Pa(O)(2)) from freely diving Weddell seals and measured arterial and venous N(2) tensions from captive elephant seals compressed in a hyperbaric chamber. Pulmonary compression resulted in a rapid spike in Pa(O)(2) and arterial CO(2) tension, followed by cyclical variation with a periodicity determined by Q(tot). The model showed that changes in diving lung volume are an efficient behavioural means to adjust the extent of gas exchange with depth. Differing models of lung compression and collapse depth caused major differences in blood and tissue N(2) estimates. Our integrated modelling approach contradicted predictions from simple models, and emphasised the complex nature of physiological interactions between circulation, lung compression and gas exchange. Overall, our work suggests the need for caution in interpretation of previous model results based on assumed collapse depths and all-or-nothing lung collapse models.

Synthesis of zirconia monoliths for chromatographic separations.

PubMed

Randon, Jérôme; Huguet, Samuel; Piram, Anne; Puy, Guillaume; Demesmay, Claire; Rocca, Jean-Louis

2006-03-17

The aim of this work is to join the advantages of two different kinds of stationary phases: monolithic columns and zirconia-based supports. On the one hand, silica monolithic columns allow a higher efficiency with a lower back-pressure than traditional packed columns. On the other hand, chromatographic stationary phases based on zirconia have a higher thermal and chemical stability and specific surface properties. Combining these advantages, a zirconia monolith with a macroporous framework could be a real improvement in separation sciences. Two main strategies can be used in order to obtain a zirconia surface on a monolithic skeleton: coating or direct synthesis. The coverage by a zirconia layer of the surface of a silica-based monolith can be performed using the chemical properties of the silanol surface groups. We realized this coverage using zirconium alkoxide and we further grafted n-dodecyl groups using phosphate derivatives. Any loss of efficiency was observed and fast separations have been achieved. The main advance reported in this paper is related to the preparation of zirconia monoliths by a sol-gel process starting from zirconium alkoxide. The synthesis parameters (hydrolysis ratio, porogen type, precursor concentration, drying step, etc.) were defined in order to produce a macroporous zirconia monoliths usable in separation techniques. We produced various homogeneous structures: zirconia rod 2 cm long with a diameter of 2.3 mm, and zirconia monolith inside fused silica capillaries with a 75 microm I.D. These monoliths have a skeleton size of 2 microm and have an average through pore size of 6 microm. Several separations have been reported.

Catalytic Ignition and Upstream Reaction Propagation in Monolith Reactors

NASA Technical Reports Server (NTRS)

Struk, Peter M.; Dietrich, Daniel L.; Miller, Fletcher J.; T'ien, James S.

2007-01-01

Using numerical simulations, this work demonstrates a concept called back-end ignition for lighting-off and pre-heating a catalytic monolith in a power generation system. In this concept, a downstream heat source (e.g. a flame) or resistive heating in the downstream portion of the monolith initiates a localized catalytic reaction which subsequently propagates upstream and heats the entire monolith. The simulations used a transient numerical model of a single catalytic channel which characterizes the behavior of the entire monolith. The model treats both the gas and solid phases and includes detailed homogeneous and heterogeneous reactions. An important parameter in the model for back-end ignition is upstream heat conduction along the solid. The simulations used both dry and wet CO chemistry as a model fuel for the proof-of-concept calculations; the presence of water vapor can trigger homogenous reactions, provided that gas-phase temperatures are adequately high and there is sufficient fuel remaining after surface reactions. With sufficiently high inlet equivalence ratio, back-end ignition occurs using the thermophysical properties of both a ceramic and metal monolith (coated with platinum in both cases), with the heat-up times significantly faster for the metal monolith. For lower equivalence ratios, back-end ignition occurs without upstream propagation. Once light-off and propagation occur, the inlet equivalence ratio could be reduced significantly while still maintaining an ignited monolith as demonstrated by calculations using complete monolith heating.

Preparation of monomeric and polymeric β-cyclodextrin functionalized monoliths for rapid isolation and purification of puerarin from Radix puerariae.

PubMed

Lv, Yongqin; Hughes, Timothy C; Hao, Xiaojuan; Mei, Danping; Tan, Tianwei

2011-08-01

Monomeric and epichlorohydrin polymerized β-CD functionalized monoliths were prepared for the rapid isolation and purification of the isoflavonoid puerarin, a well-known traditional Chinese drug, from a crude extract of Radix puerariae (root of the plant Pueraria lobata). Two copolymers poly(isocyanatoethyl methacrylate-co-methyl methacrylate-co-ethylene dimethacrylate) (poly(IEM-co-MMA-co-EDMA)) and poly(glycidyl methacrylate-co-EDMA) (poly(GMA-co-EDMA)) were developed as facile, highly reactive and versatile monolithic matrix. SEM characterization demonstrated that the modified monoliths had homogenous porous structure and morphology. The success of the chemical modification of the monolithic matrix was confirmed by Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), solid-state (13) C NMR and elemental analysis. It was demonstrated that polymeric β-CD modified monoliths had better separation and selectivity for puerarin, recovering puerarin with a purity of 96% (m%) and a yield of 93% (m%). Compared with poly(glycidyl methacrylate-co-EDMA), poly(isocyanatoethyl methacrylate-co-methyl methacrylate-co-EDMA) monolithic matrix had higher reactivity, which significantly improved the β-CD ligand density and thus the selectivity of the monoliths. Puerarin with a purity of 96% (m%) and with a yield of 89% (m%) was recovered on the monolith. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

A novel surface modification technique for forming porous polymer monoliths in poly(dimethylsiloxane).

PubMed

Burke, Jeffrey M; Smela, Elisabeth

2012-03-01

A new method of surface modification is described for enabling the in situ formation of homogenous porous polymer monoliths (PPMs) within poly(dimethylsiloxane) (PDMS) microfluidic channels that uses 365 nm UV illumination for polymerization. Porous polymer monolith formation in PDMS can be challenging because PDMS readily absorbs the monomers and solvents, changing the final monolith morphology, and because PDMS absorbs oxygen, which inhibits free-radical polymerization. The new approach is based on sequentially absorbing a non-hydrogen-abstracting photoinitiator and the monomers methyl methacrylate and ethylene diacrylate within the walls of the microchannel, and then polymerizing the surface treatment polymer within the PDMS, entangled with it but not covalently bound. Four different monolith compositions were tested, all of which yielded monoliths that were securely anchored and could withstand pressures exceeding the bonding strength of PDMS (40 psi) without dislodging. One was a recipe that was optimized to give a larger average pore size, required for low back pressure. This monolith was used to concentrate and subsequently mechanical lyse B lymphocytes.

Polymer network/carbon layer on monolith support and monolith catalytic reactor

DOEpatents

Nordquist, Andrew Francis; Wilhelm, Frederick Carl; Waller, Francis Joseph; Machado, Reinaldo Mario

2003-08-26

The present invention relates to an improved monolith catalytic reactor and a monolith support. The improvement in the support resides in a polymer network/carbon coating applied to the surface of a porous substrate and a catalytic metal, preferably a transition metal catalyst applied to the surface of the polymer network/carbon coating. The monolith support has from 100 to 800 cells per square inch and a polymer network/carbon coating with surface area of from 0.1 to 15 m.sup.2 /gram as measured by adsorption of N.sub.2 or Kr using the BET method.

Design of Water Temperature Control System Based on Single Chip Microcomputer

NASA Astrophysics Data System (ADS)

Tan, Hanhong; Yan, Qiyan

2017-12-01

In this paper, we mainly introduce a multi-function water temperature controller designed with 51 single-chip microcomputer. This controller has automatic and manual water, set the water temperature, real-time display of water and temperature and alarm function, and has a simple structure, high reliability, low cost. The current water temperature controller on the market basically use bimetal temperature control, temperature control accuracy is low, poor reliability, a single function. With the development of microelectronics technology, monolithic microprocessor function is increasing, the price is low, in all aspects of widely used. In the water temperature controller in the application of single-chip, with a simple design, high reliability, easy to expand the advantages of the function. Is based on the appeal background, so this paper focuses on the temperature controller in the intelligent control of the discussion.

"One-pot" preparation of basic amino acid-silica hybrid monolithic column for capillary electrochromatography.

PubMed

Xu, Hongrui; Xu, Zhendong; Yang, Limin; Wang, Qiuquan

2011-08-01

A novel "one-pot" strategy was developed for the preparation of amino acid (AA)-silica hybrid monolithic column. The basic AA (L-Arginine, L-Lysine and L-Histidine) was covalently incorporated into the silica hybrid skeleton via the epoxy ring-opening reaction between the amine group and the glycidyl moiety in γ-glycidoxypropyltrimethoxysilane (GPTMS), which was confirmed by elemental analysis and FT-IR studies, while the basic AA was also found to catalyze the polycondensation of tetramethoxysilane and GPTMS. The average mesopore and macropore sizes of the prepared basic AA-silica hybrid monolithic columns were 3.86 nm and 1.71 μm for the L-Lysine-silica hybrid monolith, 5.38 nm and 4.24 μm for the L-Arginine-silica hybrid monolith, and 6.38 nm and 1.24 μm for the L-Histidine-silica hybrid monolith. The hybrid monolith afforded a zwitterionic stationary phase for CEC, the direction and magnitude of EOF can be controlled by the pH of the mobile phase used. Besides an electrophoretic mechanism, the monoliths behave in a typical hydrophilic interaction with the analytes when ACN percentage in the mobile phase is over 40%. Four polar compounds (toluene, DMF, formamide and thiourea) were tested on the three AA-silica hybrid monolithic columns, and the best separation efficiency was observed in the L-Lysine-silica hybrid monolithic column, its theoretical plate height was down to 5.7 μm for thiourea when 20 mM HCOOH-HCOONH4 containing 20% ACN (pH 4.1) was used as a running buffer. The corresponding theoretical plate number for toluene, DMF, formamide and thiourea were 123,385, 103,620, 121,845 and 105,345 plates/m, respectively. Effective separation of phenols and peptides on the L-Lysine-silica hybrid monolithic column was achieved using CEC. We believe that this strategy paves a way for the easy preparation of various functional silica hybrid monolithic columns, aiming at different separation purposes. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Variably porous structures

DOEpatents

Braun, Paul V [Savoy, IL; Yu, Xindi [Urbana, IL

2011-01-18

A method of making a monolithic porous structure, comprises electrodepositing a material on a template; removing the template from the material to form a monolithic porous structure comprising the material; and electropolishing the monolithic porous structure.

UTSA-16 Growth within 3D-Printed Co-Kaolin Monoliths with High Selectivity for CO2/CH4, CO2/N2, and CO2/H2 Separation.

PubMed

Lawson, Shane; Al-Naddaf, Qasim; Krishnamurthy, Anirduh; Amour, Marc St; Griffin, Connor; Rownaghi, Ali A; Knox, James C; Rezaei, Fateme

2018-06-06

Honeycomb monoliths loaded with metal-organic frameworks (MOFs) are highly desirable adsorption contactors because of their low-pressure drop, rapid mass-transfer kinetics, and high-adsorption capacity. Moreover, three-dimensional (3D)-printing technology renders direct material modification a realistic and economic prospect. In this study, 3D printing was utilized to impregnate kaolin-based monolith with UTSA-16 metal formation precursor (Co), whereupon an internal growth was facilitated via a solvothermal synthesis approach. The cobalt weight loading in the kaolin support was varied systematically to optimize the MOF growth while retaining monolith mechanical integrity. The obtained UTSA-16 monolith with 90 wt % loading exhibited similar textural features and adsorption characteristics to its powder analogue while improving upon structural integrity. In comparison to previously developed 3D-printed UTSA-16 monoliths, the UTSA-16-kaolin monolith not only showed higher MOF loading but also higher compression stress, indicative of its robust structure. Furthermore, the 3D-printed UTSA-16-kaolin monolith displayed a comparable CO 2 adsorption capacity to the UTSA-16 powder (3.1 vs 3.5 mmol/g at 25 °C and 1 bar), which was proportional to its loading. Selectivity values of 49, 238, and 3725 were obtained for CO 2 /CH 4 , CO 2 /N 2 , and CO 2 /H 2 , respectively, demonstrating good separation potential of the 3D-printed MOF monolith for various gas mixtures, as determined by both equilibrium and dynamic adsorption measurements. Overall, this study provides a novel route for the fabrication of UTSA-16-loaded monoliths, which demonstrate both high MOF loading and mechanical integrity that could be readily applied to various CO 2 capture applications.

Method to compute the stress-energy tensor for a quantum field outside a black hole that forms from collapse

NASA Astrophysics Data System (ADS)

Anderson, Paul; Evans, Charles

2017-01-01

A method to compute the stress-energy tensor for a quantized massless minimally coupled scalar field outside the event horizon of a 4-D black hole that forms from the collapse of a spherically symmetric null shell is given. The method is illustrated in the corresponding 2-D case which is mathematically similar but is simple enough that the calculations can be done analytically. The approach to the Unruh state at late times is discussed. National Science Foundation Grant No. PHY-1505875 to Wake Forest University and National Science Foundation Grant No. PHY-1506182 to the University of North Carolina, Chapel Hill

Facile preparation of organic-silica hybrid monolith for capillary hydrophilic liquid chromatography based on "thiol-ene" click chemistry.

PubMed

Chen, Ming-Luan; Zhang, Jun; Zhang, Zheng; Yuan, Bi-Feng; Yu, Qiong-Wei; Feng, Yu-Qi

2013-04-05

In this work, a one-step approach to facile preparation of organic-inorganic hybrid monoliths was successfully developed. After vinyl-end organic monomers and azobisisobutyronitrile (AIBN) were mixed with hydrolyzed tetramethoxysilane (TMOS) and 3-mercaptopropyltrimethoxysilane (MPTMS), the homogeneous mixture was introduced into a fused-silica capillary for simultaneous polycondensation and "thiol-ene" click reaction to form the organic-silica hybrid monoliths. By employing this strategy, two types of organic-silica hybrid monoliths with positively charged quaternary ammonium and amide groups were prepared, respectively. The functional groups were successfully introduced onto the monoliths during the sol-gel process with "thiol-ene" click reaction, which was demonstrated by ζ-potential assessment, energy dispersive X-ray spectroscopy (EDX), and Fourier transform infrared (FT-IR) spectroscopy. The porous structure of the prepared monolithic columns was examined by scanning electron microscopy (SEM), nitrogen adsorption-desorption measurement, and mercury intrusion porosimetry. These results indicate the prepared organic-silica hybrid monoliths possess homogeneous column bed, large specific surface area, good mechanical stability, and excellent permeability. The prepared monolithic columns were then applied for anion-exchange/hydrophilic interaction liquid chromatography. Different types of analytes, including benzoic acids, inorganic ions, nucleosides, and nucleotides, were well separated with high column efficiency around 80,000-130,000 plates/m. Taken together, we present a facile and universal strategy to prepare organic-silica hybrid monoliths with a variety of organic monomers using one-step approach. Copyright © 2013 Elsevier B.V. All rights reserved.

Probing the Effects of Templating on the UV and Visible Light Photocatalytic Activity of Porous Nitrogen-Modified Titania Monoliths for Dye Removal.

PubMed

Nursam, Natalita M; Wang, Xingdong; Tan, Jeannie Z Y; Caruso, Rachel A

2016-07-13

Porous nitrogen-modified titania (N-titania) monoliths with tailored morphologies were prepared using phase separation and agarose gel templating techniques. The doping and templating process were simultaneously carried out in a one-pot step using alcohol amine-assisted sol-gel chemistry. The amount of polymer used in the monoliths that were prepared using phase separation was shown to affect both the physical and optical properties: higher poly(ethylene glycol) content increased the specific surface area, porosity, and visible light absorption of the final materials. For the agarose-templated monoliths, the infiltration conditions affected the monolith morphology. A porous monolith with high surface area and the least shrinkage was obtained when the N containing alkoxide precursor was infiltrated into the agarose scaffolds at 60 °C. The effect of the diverse porous morphologies on the photocatalytic activity of N-titania was studied for the decomposition of methylene blue (MB) under visible and UV light irradiation. The highest visible light activity was achieved by the agarose-templated N-titania monolith, in part due to higher N incorporation. This sample also showed better UV activity, partly because of the higher specific surface area (up to 112 m(2) g(-1)) compared to the phase separation-induced monoliths (up to 103 m(2) g(-1)). Overall, agarose-templated, porous N-titania monoliths provided better features for effectively removing the MB contaminant.

Preparation of a poly(3'-azido-3'-deoxythymidine-co-propargyl methacrylate-co-pentaerythritol triacrylate) monolithic column by in situ polymerization and a click reaction for capillary liquid chromatography of small molecules and proteins.

PubMed

Lin, Zian; Yu, Ruifang; Hu, Wenli; Zheng, Jiangnan; Tong, Ping; Zhao, Hongzhi; Cai, Zongwei

2015-07-07

Combining free radical polymerization with click chemistry via a copper-mediated azide/alkyne cycloaddition (CuAAC) reaction in a "one-pot" process, a facile approach was developed for the preparation of a poly(3'-azido-3'-deoxythymidine-co-propargyl methacrylate-co-pentaerythritol triacrylate) (AZT-co-PMA-co-PETA) monolithic column. The resulting poly(AZT-co-PMA-co-PETA) monolith showed a relatively homogeneous monolithic structure, good permeability and mechanical stability. Different ratios of monomers and porogens were used for optimizing the properties of a monolithic column. A series of alkylbenzenes, amides, anilines, and benzoic acids were used to evaluate the chromatographic properties of the polymer monolith in terms of hydrophobic, hydrophilic and cation-exchange interactions, and the results showed that the poly(AZT-co-PMA-co-PETA) monolith exhibited more flexible adjustment in chromatographic selectivity than that of the parent poly(PMA-co-PETA) and AZT-modified poly(PMA-co-PETA) monoliths. Column efficiencies for toluene, DMF, and formamide with 35,000-48,000 theoretical plates per m could be obtained at a linear velocity of 0.17 mm s(-1). The run-to-run, column-to-column, and batch-to-batch repeatabilities of the retention factors were less than 4.2%. In addition, the proposed monolith was also applied to efficient separation of sulfonamides, nucleobases and nucleosides, anesthetics and proteins for demonstrating its potential.

Facile construction of macroporous hybrid monoliths via thiol-methacrylate Michael addition click reaction for capillary liquid chromatography.

PubMed

Lin, Hui; Ou, Junjie; Liu, Zhongshan; Wang, Hongwei; Dong, Jing; Zou, Hanfa

2015-01-30

A facile approach based on thiol-methacrylate Michael addition click reaction was developed for construction of porous hybrid monolithic materials. Three hybrid monoliths were prepared via thiol-methacrylate click polymerization by using methacrylate-polyhedral oligomeric silsesquioxane (POSS) (cage mixture, n=8, 10, 12, POSS-MA) and three multi-thiol crosslinkers, 1,6-hexanedithiol (HDT), trimethylolpropane tris(3-mercaptopropionate) (TPTM) and pentaerythritol tetrakis(3-mercaptopropionate) (PTM), respectively, in the presence of porogenic solvents (n-propanol and PEG 200) and a catalyst (dimethylphenylphosphine, DMPP). The obtained monoliths possessed high thermal and chemical stabilities. Besides, they all exhibited high column efficiencies and excellent separation abilities in capillary liquid chromatography (cLC). The highest column efficiency could reach ca. 195,000N/m for butylbenzene on the monolith prepared with POSS-MA and TPTM (monolith POSS-TPTM) in reversed-phase (RP) mode at 0.64mm/s. Good chromatographic performance were all achieved in the separations of polycyclic aromatic hydrocarbons (PAHs), phenols, anilines, EPA 610 as well as bovine serum albumin (BSA) digest. The high column efficiencies in the range of 51,400-117,000N/m (achieved on the monolith POSS-PTM in RP mode) convincingly demonstrated the high separation abilities of these thiol-methacrylate based hybrid monoliths. All the results demonstrated the feasibility of the phosphines catalyzed thiol-methacrylate Michael addition click reaction in fabrication of monolithic columns with high efficiency for cLC applications. Copyright © 2014 Elsevier B.V. All rights reserved.

Galactic chemical evolution in hierarchical formation models

NASA Astrophysics Data System (ADS)

Arrigoni, Matias

2010-10-01

The chemical properties and abundance ratios of galaxies provide important information about their formation histories. Galactic chemical evolution has been modelled in detail within the monolithic collapse scenario. These models have successfully described the abundance distributions in our Galaxy and other spiral discs, as well as the trends of metallicity and abundance ratios observed in early-type galaxies. In the last three decades, however, the paradigm of hierarchical assembly in a Cold Dark Matter (CDM) cosmology has revised the picture of how structure in the Universe forms and evolves. In this scenario, galaxies form when gas radiatively cools and condenses inside dark matter haloes, which themselves follow dissipationless gravitational collapse. The CDM picture has been successful at predicting many observed properties of galaxies (for example, the luminosity and stellar mass function of galaxies, color-magnitude or star formation rate vs. stellar mass distributions, relative numbers of early and late-type galaxies, gas fractions and size distributions of spiral galaxies, and the global star formation history), though many potential problems and open questions remain. It is therefore interesting to see whether chemical evolution models, when implemented within this modern cosmological context, are able to correctly predict the observed chemical properties of galaxies. With the advent of more powerfull telescopes and detectors, precise observations of chemical abundances and abundance ratios in various phases (stellar, ISM, ICM) offer the opportunity to obtain strong constraints on galaxy formation histories and the physics that shapes them. However, in order to take advantage of these observations, it is necessary to implement detailed modeling of chemical evolution into a modern cosmological model of hierarchical assembly.

Less common applications of monoliths III. Gas chromatography

PubMed Central

Svec, Frantisek; Kurganov, Alexander A.

2008-01-01

Porous polymer monoliths emerged about two decades ago. Despite this short time, they are finding applications in a variety of fields. In addition to the most common and certainly best known use of this new category of porous media as stationary phases in liquid chromatography, monolithic materials also found their applications in other areas. This review article focuses on monoliths in capillaries designed for separations in gas chromatography. PMID:17645884

Photoinitiated grafting of porous polymer monoliths and thermoplastic polymers for microfluidic devices

DOEpatents

Frechet, Jean M. J. [Oakland, CA; Svec, Frantisek [Alameda, CA; Rohr, Thomas [Leiden, NL

2008-10-07

A microfluidic device preferably made of a thermoplastic polymer that includes a channel or a multiplicity of channels whose surfaces are modified by photografting. The device further includes a porous polymer monolith prepared via UV initiated polymerization within the channel, and functionalization of the pore surface of the monolith using photografting. Processes for making such surface modifications of thermoplastic polymers and porous polymer monoliths are set forth.

Ultralow Noise Monolithic Quantum Dot Photonic Oscillators

DTIC Science & Technology

2013-10-28

HBCU/MI) ULTRALOW NOISE MONOLITHIC QUANTUM DOT PHOTONIC OSCILLATORS LUKE LESTER UNIVERSITY OF NEW MEXICO 10/28/2013 Final Report DISTRIBUTION A...TELEPHONE NUMBER (Include area code) 24-10-2013 Final 01-06-2010 to 31-05-2013 Ultralow Noise Monolithic Quantum Dot Photonic Oscillators FA9550-10-1-0276...277-7647 Reset Grant Title: ULTRALOW NOISE MONOLITHIC QUANTUM DOT PHOTONIC OSCILLATORS Grant/Contract Number: FA9550-10-1-0276 Final Performance

Pre-Big Bang Bubbles from the Gravitational Instability of Generic String Vacua

NASA Astrophysics Data System (ADS)

Buonanno, A.; Damour, T.; Veneziano, G.

1998-06-01

We formulate the basic postulate of pre-big bang cosmology as one of 'asymptotic past triviality', by which we mean that the initial state is a generic perturbative solution of the tree-level low-energy effective action. Each such singular space-like hypersurface of gravitational collapse becomes, in the string-frame metric, the usual big-bang t = 0 hypersurface, i.e. the place of birth of a baby Friedmann universe after a period of dilaton-driven inflation. Specializing to the spherically-symmetric case, we review and reinterpret previous work on the subject, and propose a simple, scale-invariant criterion for collapse/inflation in terms of asymptotic data at past null infinity. Those data should determine whether, when, and where collapse/inflation occurs, and, when it does, fix its characteristics, including anisotropies on the big bang hypersurface whose imprint could have survived till now. Using Bayesian probability concepts, we finally attempt to answer some fine-tuning objections recently moved to the pre-gib bang scenario.

Apparent Strength Conceals Instability in a Model for the Collapse of Historical States

PubMed Central

Lawson, Daniel John; Oak, Neeraj

2014-01-01

An explanation for the political processes leading to the sudden collapse of empires and states would be useful for understanding both historical and contemporary political events. We examine political disintegration across eras, cultures and geographical scale to form a simple hypothesis that can be expressed verbally yet formulated mathematically. Factions within a state make choices described by game-theory about whether to accept the political status quo, or to attempt to better their circumstances through costly rebellion. In lieu of precise data we verify our model using sensitivity analysis. We find that a small amount of dissatisfaction is typically harmless to the state, but can trigger sudden collapse when there is a sufficient buildup of political inequality. Contrary to intuition, a state is predicted to be least stable when its leadership is at the height of its political power and thus most able to exert its influence through external warfare, lavish expense or autocratic decree. PMID:24810228

The synthesis of weak acidic type hybrid monolith via thiol-ene click chemistry and its application in hydrophilic interaction chromatography.

PubMed

Zeng, Jiao; Liu, Shengquan; Wang, Menglin; Yao, Shouzhuo; Chen, Yingzhuang

2017-05-01

In this work, a porous structure and good permeability monolithic column was polymerized in UV transparent fused-silica capillaries via photo-initiated thiol-ene click polymerization of 2,4,6,8-tetravinyl-2,4,6,8-tetramethylcyclotetrasiloxane (TMTVS), pentaerythritol tetra(3-mercaptopropionate)(PETMP), itaconic acid, respectively, in the presence of porogenic solvents (tetrahydrofuranand methanol) and an initiator (2,2-dimethoxy-2-phenylacetophenone) (DMPA) within 30 min. The physical properties of this monolith were characterized by scanning electron microscopy (SEM), Fourier transform infrared (FT-IR) spectroscopy and nitrogen adsorption/desorption measurements. For an overall evaluation of the monolith in chromatographic application, separations of polycyclic aromatic hydrocarbons (PAHs), phenols, amides and bases were carried out. The column efficiency of this monolith could be as high as 112 560 N/m. It also possesses a potential application in fabrication of monoliths with high efficiency for c-LC. In addition, the resulting monolithic column demonstrated the potential use in analysis of environment waters. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Behavior of macroporous vinyl silica and silica monolithic columns in high pressure gas chromatography.

PubMed

Maniquet, Adrien; Bruyer, Nicolas; Raffin, Guy; Baco-Antionali, Franck; Demesmay, Claire; Dugas, Vincent; Randon, Jérôme

2017-06-30

80% vinyltrimethoxysilane-based hybrid silica monoliths (80-VTMS), which have been initially developed for separation in reversed-phase liquid chromatography, have been investigated in high pressure gas chromatography separations (carrier gas pressure up to 60bar) and compared to silica monolithic columns. The behavior of both silica and 80-VTMS monolithic columns was investigated using helium, nitrogen and carbon dioxide as carrier gas. The efficiency of 80-VTMS monolithic columns was shown to vary differently than silica monolithic columns according to the temperature and the carrier gas used. Carrier gas nature was a significant parameter on the retention for both silica and vinyl columns in relation to its adsorption onto the stationary phase in such high pressure conditions. The comparison of retention and selectivity between 80-VTMS monoliths and silica was performed under helium using the logarithm of the retention factor according to the number of carbon atoms combined to Kovats indexes. The very good performances of these columns were demonstrated, allowing the separation of 8 compounds in less than 1min. Copyright © 2017 Elsevier B.V. All rights reserved.

Self-Alining End Supports for Energy Absorber

NASA Technical Reports Server (NTRS)

Alfaro-Bou, E.; Eichelberger, C. P.; Fasanella, E.

1986-01-01

Simple devices stabilize axially-loaded compressive members. Energyabsorbing column held by two end supports, which stabilize column and tolerate misalinement. Column absorbs excess load by collapsing lengthwise. Self-alining supports small, lightweight, and almost maintenance-free. Their use eliminates alinement problem, opening up more applications and providing higher reliability for compressively-loaded energy absorbers.

Rheology: liquefaction of quicksand under stress.

PubMed

Khaldoun, A; Eiser, E; Wegdam, G H; Bonn, Daniel

2005-09-29

People or animals caught in quicksand find it very hard to escape. Here we show that quicksand acts as a trap because it becomes unstable when it is forced to move--first it liquefies, and then it collapses. But a simple sinking test demonstrates that it is impossible for a human to be drawn into quicksand altogether.

Macroion induced dehydration of weak polyelectrolyte brushes

NASA Astrophysics Data System (ADS)

Zheng, Zhongli; Zhu, Y. Elaine

2014-03-01

The interaction of macroions, including polyelectrolytes, DNAs, and proteins, with polymer and cellular surfaces is critically related to many biomolecular activities, such as protein adsorption and DNA hybridization at probe surfaces. In an experimental approach to examine the macroion electrostatic interaction with a polymer surface while minimizing the long-debated hydrophobic interaction, we study the interaction of molybdenum-based inorganic polyoxometalate (POM) nanoclusters carrying 42 negative charges as model hydrophilic macroions with surface-tethered poly-2-vinylpyridine (P2VP) brushes immersed in aqueous solutions. By AFM, QCM, and contact goniometer, we have observed the collapse of P2VP chains by adding POM macroions at a constant pH. Surprisingly, added POM macroions can cause the shift of swollen-to-collapse transition pH to a lower value, in contrast to the shift to high pH value by adding simple monovalent salts. At sufficiently high POM concentration, a stable POM-P2VP composite layer, showing little dependence on solution pH and additional salts, can be formed, suggesting a simple route to construct meso-porous polymer membranes.

The importance of pelvic ring stabilization as a life-saving measure in pre-hospital - A case report commented by autopsy.

PubMed

Durão, Carlos; Alves, Magda; Barros, André; Pedrosa, Frederico

2017-08-01

Hip fractures with unstable pelvic ring have great morbidity and mortality rates. These fractures result from high energy trauma such as falls from heights, road accidents and collapsing structures or other similar mechanisms of action. We report the case of a 63 years old man, construction worker, who stood inside a ditch during a wall construction when he was surprised by this collapse, which resulted in direct trauma to the right thigh and pelvis. The autopsy revealed diaphysis fracture of the right femur with an open book pelvic fracture with severe hemorrhagic infiltration and hematoma of the pelvic muscles without arterial injury. Bone bleeding and the vascular damage associated with disruption of the sacroiliac ligaments promote a very significant bleeding. Simple maneuvers such as sheet circumferential compression to promote pelvic ring closure are effective on stabilizing and closure of the sacroiliac joint. Hip manipulation of the fracture was performed during the necropsy to demonstrate and prove how a simple sheet contention can promote stabilization of the pelvic ring by closing the sacroiliac joints in open book fractures.

Extending Femtosecond Filamentation of High Power Laser Propagating in the Atmosphere

NASA Astrophysics Data System (ADS)

Eisenmann, Shmuel; Sivan, Yonatan; Fibich, Gadi; Zigler, Arie

2008-06-01

We show experimentally for ultrashort laser pulses propagating in air, that the filamentation distance of intense laser pulses in the atmosphere can be extended and controlled with a simple double-lens setup. Using this method we were able to achieve a 20-fold delay of the filamentation distance of non-chirped 120 fs pulses propagating in air, from 16 m to 330 m. At 330 m, the collapsing pulse is sufficiently powerful to create plasma filaments. We also show that the scatter of the filaments at 330 m can be significantly reduced by tilting the second lens. We derive a simple formula for the filamentation distance, and confirm its agreement with the experimental results. We also observe that delaying the onset of filamentation increases the filament length. To the best of our knowledge, this is the longest distance reported in the literature at which plasma filaments were created and controlled. Finally, we show that the peak power at the onset of collapse is significantly higher with the double-lens setup, compared with the standard negative chirping approach.

RF Testing Of Microwave Integrated Circuits

NASA Technical Reports Server (NTRS)

Romanofsky, R. R.; Ponchak, G. E.; Shalkhauser, K. A.; Bhasin, K. B.

1988-01-01

Fixtures and techniques are undergoing development. Four test fixtures and two advanced techniques developed in continuing efforts to improve RF characterization of MMIC's. Finline/waveguide test fixture developed to test submodules of 30-GHz monolithic receiver. Universal commercially-manufactured coaxial test fixture modified to enable characterization of various microwave solid-state devices in frequency range of 26.5 to 40 GHz. Probe/waveguide fixture is compact, simple, and designed for non destructive testing of large number of MMIC's. Nondestructive-testing fixture includes cosine-tapered ridge, to match impedance wavequide to microstrip. Advanced technique is microwave-wafer probing. Second advanced technique is electro-optical sampling.

Modulation response characteristics of optical injection-locked cascaded microring laser

NASA Astrophysics Data System (ADS)

Yu, Shaowei; Pei, Li; Liu, Chao; Wang, Yiqun; Weng, Sijun

2014-09-01

Modulation bandwidth and frequency chirping of the optical injection-locked (OIL) microring laser (MRL) in the cascaded configuration are investigated. The unidirectional operation of the MRL under strong injection allows simple and cost-saving monolithic integration of the OIL system on one chip as it does not need the use of isolators between the master and slave lasers. Two cascading schemes are discussed in detail by focusing on the tailorable modulation response. The chip-to-power ratio of the cascaded optical injection-locked configuration has decreased by up to two orders of magnitude, compared with the single optical injection-locked configuration.

Graphene-supported metal oxide monolith

DOEpatents

Worsley, Marcus A.; Baumann, Theodore F.; Biener, Juergen; Biener, Monika A.; Wang, Yinmin; Ye, Jianchao; Tylski, Elijah

2017-01-10

A composition comprising at least one graphene-supported metal oxide monolith, said monolith comprising a three-dimensional structure of graphene sheets crosslinked by covalent carbon bonds, wherein the graphene sheets are coated by at least one metal oxide such as iron oxide or titanium oxide. Also provided is an electrode comprising the aforementioned graphene-supported metal oxide monolith, wherein the electrode can be substantially free of any carbon-black and substantially free of any binder.

Preparation and characterization of fluorophenylboronic acid-functionalized affinity monolithic columns for the selective enrichment of cis-diol-containing biomolecules.

PubMed

Li, Qianjin; Liu, Zhen

2015-01-01

Boronate affinity monolithic columns have been developed into an important means for the selective recognition and capture of cis-diol-containing biomolecules, such as glycoproteins, nucleosides and saccharides. The ligands of boronic acids are playing an important role in boronate affinity monolithic columns. Although several boronate affinity monoliths with high affinity toward cis-diol-containing biomolecules have been reported, only few publications are focused on their detailed procedures for preparation and characterization. This chapter describes in detail the preparation and characterization of a boronate affinity monolithic column applying 2,4-difluoro-3-formyl-phenylboronic acid (DFFPBA) as a ligand. The DFFPBA-functionalized monolithic column not only exhibited an ultrahigh boronate affinity toward cis-diol-containing biomolecules, but also showed great potential for the selective enrichment of cis-diol-containing biomolecules in real samples.

Synthesis and applications of crack-free SiO2 monolith containing CdSe/ZnS quantum dots as passive lighting sources.

PubMed

Yi, Dong Kee

2008-09-01

A reverse microemulsion technique has been used to synthesize quantum dot nanocomposites within a SiO2 surface coating. With this approach, the unique optical properties of the CdSe/ZnS quantum dots were preserved. CdSe/ZnS/SiO2 nanoparticles were homogeneously distributed in a tetramethyl orthosilicate ethanol solution and gelation process was initiated within a 10 min, and was left over night at room temperature and dried fully to achieve a solid SiO, monolith. The resulting monolith was transparent and fluorescent under ultraviolet (UV) lamp. Moreover the monolith produced was crack-free. Further studies on the photo stability of the monolith were performed using a high power UV LED device. Remarkably, quantum dots in the SiO, monolith showed better photo stability compared with those dispersed in a polymer matrix.

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.

Incorporation of ionic liquid into porous polymer monoliths to enhance the separation of small molecules in reversed-phase high-performance liquid chromatography.

PubMed

Wang, Jiafei; Bai, Ligai; Wei, Zhen; Qin, Junxiao; Ma, Yamin; Liu, Haiyan

2015-06-01

An ionic liquid was incorporated into the porous polymer monoliths to afford stationary phases with enhanced chromatographic performance for small molecules in reversed-phase high-performance liquid chromatography. The effect of the ionic liquid in the polymerization mixture on the performance of the monoliths was studied in detail. While monoliths without ionic liquid exhibited poor resolution and low efficiency, the addition of ionic liquid to the polymerization mixture provides highly increased resolution and high efficiency. The chromatographic performances of the monoliths were demonstrated by the separations of various small molecules including aromatic hydrocarbons, isomers, and homologues using a binary polar mobile phase. The present column efficiency reached 27 000 plates/m, which showed that the ionic liquid monoliths are alternative stationary phases in the separation of small molecules by high-performance liquid chromatography. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

On chip preconcentration and fluorescence labeling of model proteins by use of monolithic columns: device fabrication, optimization, and automation.

PubMed

Yang, Rui; Pagaduan, Jayson V; Yu, Ming; Woolley, Adam T

2015-01-01

Microfluidic systems with monolithic columns have been developed for preconcentration and on-chip labeling of model proteins. Monoliths were prepared in microchannels by photopolymerization, and their properties were optimized by varying the composition and concentration of the monomers to improve flow and extraction. On-chip labeling of proteins was achieved by driving solutions through the monolith by use of voltage then incubating fluorescent dye with protein retained on the monolith. Subsequently, the labeled proteins were eluted, by applying voltages to reservoirs on the microdevice, and then detected, by monitoring laser-induced fluorescence. Monoliths prepared from octyl methacrylate combine the best protein retention with the possibility of separate elution of unattached fluorescent label with 50% acetonitrile. Finally, automated on-chip extraction and fluorescence labeling of a model protein were successfully demonstrated. This method involves facile sample pretreatment, and therefore has potential for production of integrated bioanalysis microchips.

Recent Progress in Monolithic Silica Columns for High-Speed and High-Selectivity Separations.

PubMed

Ikegami, Tohru; Tanaka, Nobuo

2016-06-12

Monolithic silica columns have greater (through-pore size)/(skeleton size) ratios than particulate columns and fixed support structures in a column for chemical modification, resulting in high-efficiency columns and stationary phases. This review looks at how the size range of monolithic silica columns has been expanded, how high-efficiency monolithic silica columns have been realized, and how various methods of silica surface functionalization, leading to selective stationary phases, have been developed on monolithic silica supports, and provides information on the current status of these columns. Also discussed are the practical aspects of monolithic silica columns, including how their versatility can be improved by the preparation of small-sized structural features (sub-micron) and columns (1 mm ID or smaller) and by optimizing reaction conditions for in situ chemical modification with various restrictions, with an emphasis on recent research results for both topics.

Carprofen-imprinted monolith prepared by reversible addition-fragmentation chain transfer polymerization in room temperature ionic liquids.

PubMed

Ban, Lu; Han, Xu; Wang, Xian-Hua; Huang, Yan-Ping; Liu, Zhao-Sheng

2013-10-01

To obtain fast separation, ionic liquids were used as porogens first in combination with reversible addition-fragmentation chain transfer (RAFT) polymerization to prepare a new type of molecularly imprinted polymer (MIP) monolith. The imprinted monolithic column was synthesized using a mixture of carprofen (template), 4-vinylpyridine, ethylene glycol dimethacrylate, [BMIM]BF4, and chain transfer agent (CTA). Some polymerization factors, such as template-monomer molar ratio, the degree of crosslinking, the composition of the porogen, and the content of CTA, on the column efficiency and imprinting effect of the resulting MIP monolith were systematically investigated. Affinity screening of structurally similar compounds with the template can be achieved in 200 s on the MIP monolith due to high column efficiency (up to 12,070 plates/m) and good column permeability. Recognition mechanism of the imprinted monolith was also investigated.

Monolithic in-based III-V compound semiconductor focal plane array cell with single stage CCD output

NASA Technical Reports Server (NTRS)

Fossum, Eric R. (Inventor); Cunningham, Thomas J. (Inventor); Krabach, Timothy N. (Inventor); Staller, Craig O. (Inventor)

1994-01-01

A monolithic semiconductor imager includes an indium-based III-V compound semiconductor monolithic active layer of a first conductivity type, an array of plural focal plane cells on the active layer, each of the focal plane cells including a photogate over a top surface of the active layer, a readout circuit dedicated to the focal plane cell including plural transistors formed monolithically with the monolithic active layer and a single-stage charge coupled device formed monolithically with the active layer between the photogate and the readout circuit for transferring photo-generated charge accumulated beneath the photogate during an integration period to the readout circuit. The photogate includes thin epitaxial semiconductor layer of a second conductivity type overlying the active layer and an aperture electrode overlying a peripheral portion of the thin epitaxial semiconductor layer, the aperture electrode being connectable to a photogate bias voltage.

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

El-Ghoroury, Hussein S.; Yeh, Milton; Chen, J. C., E-mail: jc.chen@ostendo.com

Specially designed intermediate carrier blocking layers (ICBLs) in multi-active regions of III-nitride LEDs were shown to be effective in controlling the carrier injection distribution across the active regions. In principle, the majority of carriers, both holes and electrons, can be guided into targeted quantum wells and recombine to generate light of specific wavelengths at controlled current-densities. Accordingly we proposed and demonstrated a novel monolithic InGaN-based LED to achieve three primary colors of light from one device at selected current densities. This LED structure, which has three different sets of quantum wells separated with ICBLs for three primary red-green-blue (RGB) colors,more » was grown by metal-organic chemical vapor deposition (MOCVD). Results show that this LED can emit light ranging from 460 to 650 nm to cover the entire visible spectrum. The emission wavelength starts at 650 nm and then decreases to 460 nm or lower as the injection current increases. In addition to three primary colors, many other colors can be obtained by color mixing techniques. To the best of our knowledge, this is the first demonstration of monolithic full-color LED grown by a simple growth technique without using re-growth process.« less

Measurements and simulations of MAPS (Monolithic Active Pixel Sensors) response to charged particles - a study towards a vertex detector at the ILC

NASA Astrophysics Data System (ADS)

Maczewski, Lukasz

2010-05-01

The International Linear Collider (ILC) is a project of an electron-positron (e+e-) linear collider with the centre-of-mass energy of 200-500 GeV. Monolithic Active Pixel Sensors (MAPS) are one of the proposed silicon pixel detector concepts for the ILC vertex detector (VTX). Basic characteristics of two MAPS pixel matrices MIMOSA-5 (17 μm pixel pitch) and MIMOSA-18 (10 μm pixel pitch) are studied and compared (pedestals, noises, calibration of the ADC-to-electron conversion gain, detector efficiency and charge collection properties). The e+e- collisions at the ILC will be accompanied by intense beamsstrahlung background of electrons and positrons hitting inner planes of the vertex detector. Tracks of this origin leave elongated clusters contrary to those of secondary hadrons. Cluster characteristics and orientation with respect to the pixels netting are studied for perpendicular and inclined tracks. Elongation and precision of determining the cluster orientation as a function of the angle of incidence were measured. A simple model of signal formation (based on charge diffusion) is proposed and tested using the collected data.

Implementation of the multi-channel monolith reactor in an optimisation procedure for heterogeneous oxidation catalysts based on genetic algorithms.

PubMed

Breuer, Christian; Lucas, Martin; Schütze, Frank-Walter; Claus, Peter

2007-01-01

A multi-criteria optimisation procedure based on genetic algorithms is carried out in search of advanced heterogeneous catalysts for total oxidation. Simple but flexible software routines have been created to be applied within a search space of more then 150,000 individuals. The general catalyst design includes mono-, bi- and trimetallic compositions assembled out of 49 different metals and depleted on an Al2O3 support in up to nine amount levels. As an efficient tool for high-throughput screening and perfectly matched to the requirements of heterogeneous gas phase catalysis - especially for applications technically run in honeycomb structures - the multi-channel monolith reactor is implemented to evaluate the catalyst performances. Out of a multi-component feed-gas, the conversion rates of carbon monoxide (CO) and a model hydrocarbon (HC) are monitored in parallel. In combination with further restrictions to preparation and pre-treatment a primary screening can be conducted, promising to provide results close to technically applied catalysts. Presented are the resulting performances of the optimisation process for the first catalyst generations and the prospect of its auto-adaptation to specified optimisation goals.

Affordable, Robust Ceramic Joining Technology (ARCJoinT) for High Temperature Applications

NASA Technical Reports Server (NTRS)

Singh, M.

1998-01-01

Ceramic joining is recognized as one of the enabling technologies for the successful utilization of silicon carbide-based monolithic ceramic and fiber reinforced composite components in a number of demanding and high temperature applications in aerospace and ground-based systems. An affordable, robust ceramic joining technology (ARCJoinT) for joining of silicon carbide-based ceramics and fiber reinforced composites has been developed. This technique is capable of producing joints with tailorable thickness and composition. A wide variety of silicon carbide-based ceramics and composites, in different shapes and sizes, have been joined using this technique. The room and high temperature mechanical properties and fractography of ceramic joints have been reported. In monolithic silicon carbide ceramics, these joints maintain their mechanical strength up to 1350 C in air. There is no change in the mechanical strength of joints in silicon carbide matrix composites up to 1200 C in air. In composites, simple butt joints yield only about 20% of the ultimate strength of the parent materials. This technology is suitable for the joining of large and complex shaped ceramic and composite components, and with certain modifications, can be applied to repair of ceramic components damaged in service.

Crack-free polydimethylsiloxane-bioactive glass-poly(ethylene glycol) hybrid monoliths with controlled biomineralization activity and mechanical property for bone tissue regeneration.

PubMed

Chen, Jing; Du, Yuzhang; Que, Wenxiu; Xing, Yonglei; Chen, Xiaofeng; Lei, Bo

2015-12-01

Crack-free organic-inorganic hybrid monoliths with controlled biomineralization activity and mechanical property have an important role for highly efficient bone tissue regeneration. Here, biomimetic and crack-free polydimethylsiloxane (PDMS)-modified bioactive glass (BG)-poly(ethylene glycol) (PEG) (PDMS-BG-PEG) hybrids monoliths were prepared by a facile sol-gel technique. Results indicate that under the assist of co-solvents, BG sol and PDMS and PEG could be hybridized at a molecular level, and effects of the PEG molecular weight on the structure, biomineralization activity, and mechanical property of the as-prepared hybrid monoliths were also investigated in detail. It is found that an addition of low molecular weight PEG can significantly prevent the formation of cracks and speed up the gelation of the hybrid monoliths, and the surface microstructure of the hybrid monoliths can be changed from the porous to the smooth as the PEG molecular weight increases. Additionally, the hybrid monoliths with low molecular weight PEG show the high formation of the biological apatite layer, while the hybrids with high molecular weight PEG exhibit negligible biomineralization ability in simulated body fluid (SBF). Furthermore, the PDMS-BG-PEG 600 hybrid monolith has significantly high compressive strength (32 ± 3 MPa) and modulus (153 ± 11 MPa), as well as good cell biocompatibility by supporting osteoblast (MC3T3-E1) attachment and proliferation. These results indicate that the as-prepared PDMS-BG-PEG hybrid monoliths may have promising applications for bone tissue regeneration. Copyright © 2015 Elsevier B.V. All rights reserved.

Preparation of polymer monolithic column functionalized by arsonic acid groups for mixed-mode capillary liquid chromatography.

PubMed

Qin, Zhang-Na; Yu, Qiong-Wei; Wang, Ren-Qi; Feng, Yu-Qi

2018-04-27

A mixed-mode polymer monolithic column functionalized by arsonic acid groups was prepared by single-step in situ copolymerization of monomers p-methacryloylaminophenylarsonic acid (p-MAPHA) and pentaerythritol triacrylate (PETA). The prepared poly(p-MAPHA-co-PETA) monolithic column has a homogeneous monolithic structure with good permeability and mechanical stability. Zeta potential measurements reveal that the monolithic stationary phase holds a negative surface charge when the mobile phase resides in the pH range of 3.0-8.0. The retention mechanisms of prepared monolithic column are explored by the separation of selected polycyclic aromatic hydrocarbons (PAHs), nucleosides, and three basic compounds. The results indicate that the column functions in three different separation modes associated with reversed-phase chromatography based on hydrophobic interaction, hydrophilic interaction chromatography, and cation-exchange chromatography. The column efficiency of prepared monolithic column is estimated to be 70,000 and 76,000 theoretical plates/m for thiourea and naphthalene, respectively, at a linear flow velocity of 0.85 mm/s using acetonitrile/H 2 O (85/15, v/v) as the mobile phase. Furthermore, an analysis of the retention factors obtained for the PAHs indicates that the prepared monolithic column exhibits good reproducibility with relative standard deviations of 2.9%, 4.0%, and 4.7% based on run-to-run injections, column-to-column preparation, and batch-to-batch preparation, respectively. Finally, we investigate the separation performance of the proposed monolithic column for select phenols, sulfonamides, nucleobases and nucleosides. Copyright © 2018 Elsevier B.V. All rights reserved.

GaAs monolithic R.F. modules for SARSAT distress beacons

NASA Technical Reports Server (NTRS)

Cauley, Michael A.

1991-01-01

Monolithic GaAs UHF components for use in SARSAT Emergency Distress beacons are under development by Microwave Monolithics, Inc., Simi Valley, CA. The components include a bi-phase modulator, driver amplifier, and a 5 watt power amplifier.

GaAs monolithic RF modules for SARSAT distress beacons

NASA Technical Reports Server (NTRS)

Cauley, Michael A.

1991-01-01

Monolithic GaAs UHF components for use in SARSAT Emergency Distress beacons are under development by Microwave Monolithics, Inc., Simi Valley, CA. The components include a bi-phase modulator, driver amplifier, and a 5 watt power amplifier.

Monolithic Domes.

ERIC Educational Resources Information Center

Lanham, Carol

2002-01-01

Describes how the energy savings, low cost, and near-absolute protection from tornadoes provided by monolithic domes is starting to appeal to school districts for athletic and other facilities, including the Italy (Texas) Independent School District. Provides an overview of monolithic dome construction. (EV)

Adsorption-Induced Deformation of Hierarchically Structured Mesoporous Silica—Effect of Pore-Level Anisotropy

PubMed Central

2017-01-01

The goal of this work is to understand adsorption-induced deformation of hierarchically structured porous silica exhibiting well-defined cylindrical mesopores. For this purpose, we performed an in situ dilatometry measurement on a calcined and sintered monolithic silica sample during the adsorption of N2 at 77 K. To analyze the experimental data, we extended the adsorption stress model to account for the anisotropy of cylindrical mesopores, i.e., we explicitly derived the adsorption stress tensor components in the axial and radial direction of the pore. For quantitative predictions of stresses and strains, we applied the theoretical framework of Derjaguin, Broekhoff, and de Boer for adsorption in mesopores and two mechanical models of silica rods with axially aligned pore channels: an idealized cylindrical tube model, which can be described analytically, and an ordered hexagonal array of cylindrical mesopores, whose mechanical response to adsorption stress was evaluated by 3D finite element calculations. The adsorption-induced strains predicted by both mechanical models are in good quantitative agreement making the cylindrical tube the preferable model for adsorption-induced strains due to its simple analytical nature. The theoretical results are compared with the in situ dilatometry data on a hierarchically structured silica monolith composed by a network of mesoporous struts of MCM-41 type morphology. Analyzing the experimental adsorption and strain data with the proposed theoretical framework, we find the adsorption-induced deformation of the monolithic sample being reasonably described by a superposition of axial and radial strains calculated on the mesopore level. The structural and mechanical parameters obtained from the model are in good agreement with expectations from independent measurements and literature, respectively. PMID:28547995

Adsorption-Induced Deformation of Hierarchically Structured Mesoporous Silica-Effect of Pore-Level Anisotropy.

PubMed

Balzer, Christian; Waag, Anna M; Gehret, Stefan; Reichenauer, Gudrun; Putz, Florian; Hüsing, Nicola; Paris, Oskar; Bernstein, Noam; Gor, Gennady Y; Neimark, Alexander V

2017-06-06

The goal of this work is to understand adsorption-induced deformation of hierarchically structured porous silica exhibiting well-defined cylindrical mesopores. For this purpose, we performed an in situ dilatometry measurement on a calcined and sintered monolithic silica sample during the adsorption of N 2 at 77 K. To analyze the experimental data, we extended the adsorption stress model to account for the anisotropy of cylindrical mesopores, i.e., we explicitly derived the adsorption stress tensor components in the axial and radial direction of the pore. For quantitative predictions of stresses and strains, we applied the theoretical framework of Derjaguin, Broekhoff, and de Boer for adsorption in mesopores and two mechanical models of silica rods with axially aligned pore channels: an idealized cylindrical tube model, which can be described analytically, and an ordered hexagonal array of cylindrical mesopores, whose mechanical response to adsorption stress was evaluated by 3D finite element calculations. The adsorption-induced strains predicted by both mechanical models are in good quantitative agreement making the cylindrical tube the preferable model for adsorption-induced strains due to its simple analytical nature. The theoretical results are compared with the in situ dilatometry data on a hierarchically structured silica monolith composed by a network of mesoporous struts of MCM-41 type morphology. Analyzing the experimental adsorption and strain data with the proposed theoretical framework, we find the adsorption-induced deformation of the monolithic sample being reasonably described by a superposition of axial and radial strains calculated on the mesopore level. The structural and mechanical parameters obtained from the model are in good agreement with expectations from independent measurements and literature, respectively.

Monolithically integrated quantum dot optical gain modulator with semiconductor optical amplifier for 10-Gb/s photonic transmission

NASA Astrophysics Data System (ADS)

Yamamoto, Naokatsu; Akahane, Kouichi; Umezawa, Toshimasa; Kawanishi, Tetsuya

2015-03-01

Short-range interconnection and/or data center networks require high capacity and a large number of channels in order to support numerous connections. Solutions employed to meet these requirements involve the use of alternative wavebands to increase the usable optical frequency range. We recently proposed the use of the T- and O-bands (Thousand band: 1000-1260 nm, Original band: 1260-1360 nm) as alternative wavebands because large optical frequency resources (>60 THz) can be easily employed. In addition, a simple and compact Gb/s-order high-speed optical modulator is a critical photonic device for short-range communications. Therefore, to develop an optical modulator that acts as a highfunctional photonic device, we focused on the use of self-assembled quantum dots (QDs) as a three-dimensional (3D) confined structure because QD structures are highly suitable for realizing broadband optical gain media in the T+O bands. In this study, we use the high-quality broadband QD optical gain to develop a monolithically integrated QD optical gain modulator (QD-OGM) device that has a semiconductor optical amplifier (QD-SOA) for Gb/s-order highspeed optical data generation in the 1.3-μm waveband. The insertion loss of the device can be compensated through the SOA, and we obtained an optical gain change of up to ~7 dB in the OGM section. Further, we successfully demonstrate a 10-Gb/s clear eye opening using the QD-OGM/SOA device with a clock-data recovery sequence at the receiver end. These results suggest that the monolithic QD-EOM/SOA is suitable for increasing the number of wavelength channels for smart short-range communications.

Interfacial free energy governs single polystyrene chain collapse in water and aqueous solutions.

PubMed

Li, Isaac T S; Walker, Gilbert C

2010-05-12

The hydrophobic interaction is significantly responsible for driving protein folding and self-assembly. To understand it, the thermodynamics, the role of water structure, the dewetting process surrounding hydrophobes, and related aspects have undergone extensive investigations. Here, we examine the hypothesis that polymer-solvent interfacial free energy is adequate to describe the energetics of the collapse of a hydrophobic homopolymer chain at fixed temperature, which serves as a much simplified model for studying the hydrophobic collapse of a protein. This implies that changes in polymer-solvent interfacial free energy should be directly proportional to the force to extend a collapsed polymer into a bad solvent. To test this hypothesis, we undertook single-molecule force spectroscopy on a collapsed, single, polystyrene chain in water-ethanol and water-salt mixtures where we measured the monomer solvation free energy from an ensemble average conformations. Different proportions within the binary mixture were used to create solvents with different interfacial free energies with polystyrene. In these mixed solvents, we observed a linear correlation between the interfacial free energy and the force required to extend the chain into solution, which is a direct measure of the solvation free energy per monomer on a single chain at room temperature. A simple analytical model compares favorably with the experimental results. This knowledge supports a common assumption that explicit water solvent may not be necessary for cases whose primary concerns are hydrophobic interactions and hydrophobic hydration.

Effect of supersonic relative motion between baryons and dark matter on collapsed objects

NASA Astrophysics Data System (ADS)

Asaba, Shinsuke; Ichiki, Kiyotomo; Tashiro, Hiroyuki

2016-01-01

Great attention is given to the first star formation and the epoch of reionization as main targets of planned large radio interferometries (e.g. Square Kilometre Array). Recently, it is claimed that the supersonic relative velocity between baryons and cold dark matter can suppress the abundance of first stars and impact the cosmological reionization process. Therefore, in order to compare observed results with theoretical predictions it is important to examine the effect of the supersonic relative motion on the small-scale structure formation. In this paper, we investigate this effect on the nonlinear structure formation in the context of the spherical collapse model in order to understand the fundamental physics in a simple configuration. We show the evolution of the dark matter sphere with the relative velocity by both using N-body simulations and numerically calculating the equation of motion for the dark matter mass shell. The effects of the relative motion in the spherical collapse model appear as the delay of the collapse time of dark matter halos and the decrease of the baryon mass fraction within the dark matter sphere. Based on these results, we provide the fitting formula of the critical density contrast for collapses with the relative motion effect and calculate the mass function of dark matter halos in the Press-Schechter formalism. As a result, the relative velocity decreases the abundance of dark matter halos whose mass is smaller than 108M⊙/h .

Optimization of monolithic columns for microfluidic devices

NASA Astrophysics Data System (ADS)

Pagaduan, Jayson V.; Yang, Weichun; Woolley, Adam T.

2011-06-01

Monolithic columns offer advantages as solid-phase extractors because they offer high surface area that can be tailored to a specific function, fast mass transport, and ease of fabrication. Porous glycidyl methacrylate-ethylene glycol dimethacrylate monoliths were polymerized in-situ in microfluidic devices, without pre-treatment of the poly(methyl methacrylate) channel surface. Cyclohexanol, 1-dodecanol and Tween 20 were used to control the pore size of the monoliths. The epoxy groups on the monolith surface can be utilized to immobilize target-specific probes such as antibodies, aptamers, or DNA for biomarker detection. Microfluidic devices integrated with solid-phase extractors should be useful for point-of-care diagnostics in detecting specific biomarkers from complex biological fluids.

Constraints and System Primitives in Achieving Multilevel Security in Real Time Distributed System Environment

DTIC Science & Technology

1994-04-18

because they represent a microkernel and monolithic kernel approach to MLS operating system issues. TMACH is I based on MACH, a distributed operating...the operating system is [L.sed on a microkernel design or a monolithic kernel design. This distinction requires some caution since monolithic operating...are provided by 3 user-level processes, in contrast to standard UNIX, which has a large monolithic kernel that pro- I - 22 - Distributed O)perating

Synergism between polyurethane and polydopamine in the synthesis of Ni-Fe alloy monoliths.

PubMed

Naresh Kumar, Thangavel; Sivabalan, Santhana; Chandrasekaran, Naveen; Phani, Kanala Lakshminarasimha

2015-02-04

Herein, we report the first synthesis of a light-weight macroporous 3-D alloy monolith of Ni-Fe/C using synergism between polydopamine (pDA) and polyurethane (pU); in situ formed polyurethane (pU) enables efficient mixing of pDA (carbon source) and Ni-FeOx resulting in Ni-Fe alloy monoliths at a temperature as low as ∼600 °C. The monolithic Ni-Fe/C exhibits enhanced oxygen evolution activity.

Understanding low temperature oxidation activity of nanoarray-based monolithic catalysts: from performance observation to structural and chemical insights

DOE PAGES

Du, Shoucheng; Tang, Wenxiang; Guo, Yanbing; ...

2016-12-30

Monolithic catalysts have been widely used in automotive, chemical, and energy relevant industries. Nano-array based monolithic catalysts have been developed, demonstrating high catalyst utilization efficiency and good thermal/mechanical robustness. Compared with the conventional wash-coat based monolithic catalysts, they have shown advances in precise and optimum microstructure control and feasibility in correlating materials structure with properties. Recently, the nano-array based monolithic catalysts have been studied for low temperature oxidation of automotive engine exhaust and exhibited interesting and promising catalytic activities. Here, this review focuses on discussing the key catalyst structural parameters that affect the catalytic performance from the following aspects, (1)more » geometric shape and crystal planes, (2) guest atom doping and defects, (3) array size and size-assisted active species loading, and (4) the synergy effect of metal oxide in composite nano-arrays. Prior to the discussion, an overview of the current status of synthesis and development of the nano-array based monolithic catalysts is introduced. The performance of these materials in low temperature simulated engine exhaust oxidation is also demonstrated. Finally, we hope this review will elucidate the science and chemistry behind the good oxidation performance of the nanoarray- based monolithic catalysts, and serve as a timely and useful research guide for rational design and further improvement of the nano-array based monolithic catalysts for automobile emission control.« less

Understanding low temperature oxidation activity of nanoarray-based monolithic catalysts: from performance observation to structural and chemical insights

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

Du, Shoucheng; Tang, Wenxiang; Guo, Yanbing

Monolithic catalysts have been widely used in automotive, chemical, and energy relevant industries. Nano-array based monolithic catalysts have been developed, demonstrating high catalyst utilization efficiency and good thermal/mechanical robustness. Compared with the conventional wash-coat based monolithic catalysts, they have shown advances in precise and optimum microstructure control and feasibility in correlating materials structure with properties. Recently, the nano-array based monolithic catalysts have been studied for low temperature oxidation of automotive engine exhaust and exhibited interesting and promising catalytic activities. Here, this review focuses on discussing the key catalyst structural parameters that affect the catalytic performance from the following aspects, (1)more » geometric shape and crystal planes, (2) guest atom doping and defects, (3) array size and size-assisted active species loading, and (4) the synergy effect of metal oxide in composite nano-arrays. Prior to the discussion, an overview of the current status of synthesis and development of the nano-array based monolithic catalysts is introduced. The performance of these materials in low temperature simulated engine exhaust oxidation is also demonstrated. Finally, we hope this review will elucidate the science and chemistry behind the good oxidation performance of the nanoarray- based monolithic catalysts, and serve as a timely and useful research guide for rational design and further improvement of the nano-array based monolithic catalysts for automobile emission control.« less

Preparation of epoxy-based macroporous monolithic columns for the fast and efficient immunofiltration of Staphylococcus aureus.

PubMed

Ott, Sonja; Niessner, Reinhard; Seidel, Michael

2011-08-01

Macroporous epoxy-based monolithic columns were used for immunofiltration of bacteria. The prepared monolithic polymer support is hydrophilic and has large pore sizes of 21 μm without mesopores. A surface chemistry usually applied for immobilization of antibodies on glass slides is successfully transferred to monolithic columns. Step-by-step, the surface of the epoxy-based monolith is hydrolyzed, silanized, coated with poly(ethylene glycol diamine) and activated with the homobifunctional crosslinker di(N-succinimidyl)carbonate for immobilization of antibodies on the monolithic columns. The functionalization steps are characterized to ensure the coating of each monolayer. The prepared antibody-immobilized monolithic column is optimized for immunofiltration to enrich Staphylococcus aureus as an important food contaminant. Different kinds of geometries of monolithic columns, flow rates and elution buffers are tested with the goal to get high recoveries in the shortest enrichment time as possible. An effective capture of S. aureus was achieved at a flow rate of 7.0 mL/min with low backpressures of 20.1±5.4 mbar enabling a volumetric enrichment of 1000 within 145 min. The bacteria were quantified by flow cytometry using a double-labeling approach. After immunofiltration the sensitivity was significantly increased and a detection limit of the total system of 42 S. aureus/mL was reached. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Incorporation of metal-organic framework HKUST-1 into porous polymer monolithic capillary columns to enhance the chromatographic separation of small molecules.

PubMed

Yang, Shengchao; Ye, Fanggui; Lv, Qinghui; Zhang, Cong; Shen, Shufen; Zhao, Shulin

2014-09-19

Metal-organic framework (MOF) HKUST-1 nanoparticles have been incorporated into poly(glycidyl methacrylate-co-ethylene dimethacrylate) (HKUST-1-poly(GMA-co-EDMA)) monoliths to afford stationary phases with enhanced chromatographic performance of small molecules in the reversed phase capillary liquid chromatography. The effect of HKUST-1 nanoparticles in the polymerization mixture on the performance of the monolithic column was explored in detail. While the bare poly(GMA-co-EDMA) monolith exhibited poor resolution (Rs<1.0) and low efficiency (800-16,300plates/m), addition of a small amount of HKUST-1 nanoparticles to the polymerization mixture provide high increased resolution (Rs≥1.3) and high efficiency ranged from 16,300 to 44,300plates/m. Chromatographic performance of HKUST-1-poly(GMA-co-EDMA) monolith was demonstrated by separation of various analytes including polycyclic aromatic hydrocarbons, ethylbenzene and styrene, phenols and aromatic acids using a binary polar mobile phase (CH3CN/H2O). The HKUST-1-poly(GMA-co-EDMA) monolith displayed enhanced hydrophobic and π-π interaction characteristics in the reversed phase separation of test analytes compared to the bare poly(GMA-co-EDMA) monolith. The experiment results showed that HKUST-1-poly(GMA-co-EDMA) monoliths are an alternative to enhance the chromatographic separation of small molecules. Copyright © 2014 Elsevier B.V. All rights reserved.

The effect of charged groups on hydrophilic monolithic stationary phases on their chromatographic properties.

PubMed

Li, Haibin; Liu, Chusheng; Wang, Qiqin; Zhou, Haibo; Jiang, Zhengjin

2016-10-21

In order to investigate the effect of charged groups present in hydrophilic monolithic stationary phases on their chromatographic properties, three charged hydrophilic monomers, i.e. N,N-dimethyl-N-acryloyloxyethyl-N-(3-sulfopropyl)ammonium betaine (SPDA), [2-(acryloyloxy)ethyl]trimethylammonium chloride (AETA), and 3-sulfopropyl acrylate potassium salt (SPA) were co-polymerized with the crosslinker N,N'-methylenebisacrylamide (MBA), respectively. The physicochemical properties of the three resulting charged hydrophilic monolithic columns were evaluated using scanning electron microscopy, ζ-potential analysis and micro-HPLC. High column efficiency was obtained on the three monolithic columns at a linear velocity of 1mm/s using thiourea as test compound. Comparative characterization of the three charged HILIC phases was then carried out using a set of model compounds, including nucleobases, nucleosides, benzoic acid derivatives, phenols, β-blockers and small peptides. Depending on the combination of stationary phase/mobile phase/solute, both hydrophilic interaction and other potential secondary interactions, including electrostatic interaction, hydrogen-bonding interaction, molecular shape selectivity, could contribute to the over-all retention of the analytes. Because of the strong electrostatic interaction provided by the quaternary ammonium groups in the poly (AETA-co-MBA) monolith, this cationic HILIC monolith exhibited the strongest retention for benzoic acid derivatives and small peptides with distorted peak shapes and the weakest retention for basic β-blockers. The sulfonyl groups on the poly (SPA-co-MBA) hydrophilic monolith could provide strong electrostatic attraction and hydrogen bonding for positively charged analytes and hydrogen-donor/acceptor containing analytes, respectively. Therefore, basic drugs, nucleobases and nucleotides exhibited the strongest retention on this anionic monolith. Because of the weak but distinct cation exchange properties of the zwitterionic poly (SPDA-co-MBA) hydrophilic monolith, it exhibited the best separation for most test analytes (including phenols, β-blockers and small peptides) in terms of selectivity, peak shape and analysis time. The poly (AETA-co-MBA) hydrophilic monolithic column provides the best separation of nucleobases and nucleosides. These results could guide the selection and application of these charged HILIC monoliths in the future. Copyright © 2016 Elsevier B.V. All rights reserved.

Titanium-scaffolded organic-monolithic stationary phases for ultra-high-pressure liquid chromatography.

PubMed

Vonk, Rudy J; Vaast, Axel; Eeltink, Sebastiaan; Schoenmakers, Peter J

2014-09-12

Organic-polymer monoliths with overall dimensions larger than one millimetre are prone to rupture - either within the monolith itself or between the monoliths and the containing wall - due to the inevitable shrinkage accompanying the formation of a cross-linked polymeric network. This problem has been addressed by creating titanium-scaffolded poly(styrene-co-divinylbenzene) (S-co-DVB) monoliths. Titanium-scaffolded monoliths were successfully used in liquid chromatography at very high pressures (up to 80MPa) and using gradients spanning the full range of water-acetonitrile compositions (0 to 100%). The kinetic-performance of (50-mm long) titanium-scaffolded monoliths was compared to that of similar monolith created in 1-mm i.d. glass-lined tubing at pressures up to 50MPa. The peak capacities obtained with the titanium-scaffolded column was about 30% lower. An increased Eddy-diffusion, due to the pillar-structure, and a decreased permeability are thought to be the main reasons for this reduced kinetic-performance. No decrease in performance was observed when the titanium-scaffolded columns were operated at pressures of 80MPa for up to 12h. The column-to-column repeatability (n=5) was acceptable in terms of observed peak widths at half heights (RSD ca. 10%) The run-to-run repeatability (n=135) in terms of retention times and peak widths at half height were found to be good. Titanium-scaffolded columns coupled in series up to a combined length of (200mm) were used for the analyses of a complex Escherichia coli protein sample. Our experiments demonstrate that columns based on titanium-scaffolded organic-polymer monolith can be operated under strenuous conditions without loss in performance. The titanium-scaffolded approach makes it feasible to create organic-polymer monoliths in wide-bore columns with accurate temperature control. Copyright © 2014 Elsevier B.V. All rights reserved.

Bounds on quantum collapse models from matter-wave interferometry: calculational details

NASA Astrophysics Data System (ADS)

Toroš, Marko; Bassi, Angelo

2018-03-01

We present a simple derivation of the interference pattern in matter-wave interferometry predicted by a class of quantum master equations. We apply the obtained formulae to the following collapse models: the Ghirardi-Rimini-Weber (GRW) model, the continuous spontaneous localization (CSL) model together with its dissipative (dCSL) and non-Markovian generalizations (cCSL), the quantum mechanics with universal position localization (QMUPL), and the Diósi-Penrose (DP) model. We discuss the separability of the dynamics of the collapse models along the three spatial directions, the validity of the paraxial approximation, and the amplification mechanism. We obtain analytical expressions both in the far field and near field limits. These results agree with those already derived in the Wigner function formalism. We compare the theoretical predictions with the experimental data from two recent matter-wave experiments: the 2012 far-field experiment of Juffmann T et al (2012 Nat. Nanotechnol. 7 297-300) and the 2013 Kapitza-Dirac-Talbot-Lau (KDTL) near-field experiment of Eibenberger et al (2013 Phys. Chem. Chem. Phys. 15 14696-700). We show the region of the parameter space for each collapse model that is excluded by these experiments. We show that matter-wave experiments provide model-insensitive bounds that are valid for a wide family of dissipative and non-Markovian generalizations.

Chiral monolithic absorbent constructed by optically active helical-substituted polyacetylene and graphene oxide: preparation and chiral absorption capacity.

PubMed

Li, Weifei; Wang, Bo; Yang, Wantai; Deng, Jianping

2015-02-01

Chiral monolithic absorbent is successfully constructed for the first time by using optically active helical-substituted polyacetylene and graphene oxide (GO). The preparative strategy is facile and straightforward, in which chiral-substituted acetylene monomer (Ma), cross-linker (Mb), and alkynylated GO (Mc) undergo copolymerization to form the desired monolithic absorbent in quantitative yield. The resulting monoliths are characterized by circular dichroism, UV-vis absorption, scanning electron microscopy (SEM), FT-IR, Raman, energy-dispersive spectrometer (EDS), X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET), XPS, and thermogravimetric analysis (TGA) techniques. The polymer chains derived from Ma form chiral helical structures and thus provide optical activity to the monoliths, while GO sheets contribute to the formation of porous structures. The porous structure enables the monolithic absorbents to demonstrate a large swelling ratio in organic solvents, and more remarkably, the helical polymer chains provide optical activity and further enantio-differentiating absorption ability. The present study establishes an efficient and versatile methodology for preparing novel functional materials, in particular monolithic chiral materials based on substituted polyacetylene and GO. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

One-pot synthesis of zeolitic imidazolate framework-8/poly (methyl methacrylate-ethyleneglycol dimethacrylate) monolith coating for stir bar sorptive extraction of phytohormones from fruit samples followed by high performance liquid chromatography-ultraviolet detection.

PubMed

You, Linna; He, Man; Chen, Beibei; Hu, Bin

2017-11-17

In this work, zeolitic imidazolate framework-8 (ZIF-8)/poly (methyl methacrylate-ethyleneglycol dimethacrylate) (MMA-EGDMA) composite monolith was in situ synthesized on stir bar by one-pot polymerization. Compared with the neat monolith, ZIF-8/poly(MMA-EGDMA) composite monolith has larger surface area and pore volume. It also exhibits higher extraction efficiency for target phytohormones than poly(MMA-EGDMA) monolith and commercial polyethylene glycol (PEG) coated stir bar. Based on it, a method of ZIF-8/poly(MMA-EGDMA) monolith coated stir bar sorptive extraction (SBSE)-high performance liquid chromatography-ultraviolet detection (HPLC-UV) was established for the analysis of five phytohormones in apple and pear samples. The developed method exhibited low limits of detection (0.11-0.51μg/L), wide linear range (0.5-500μg/L) and good recoveries (82.7-111%), which demonstrated good application potential of the ZIF-8/monolith coated stir bar in trace analysis of organic compounds. Copyright © 2017 Elsevier B.V. All rights reserved.

One-Pot Approach to Prepare Organo-silica Hybrid Capillary Monolithic Column with Intact Mesoporous Silica Nanoparticle as Building Block.

PubMed

Liu, Shengju; Peng, Jiaxi; Liu, Zheyi; Liu, Zhongshan; Zhang, Hongyan; Wu, Ren'an

2016-10-04

A facile "one-pot" approach to prepare organo-silica hybrid capillary monolithic column with intact mesoporous silica nanoparticle (IMSN) as crosslinker and building block was described. An IMSN crosslinked octadecyl-silica hybrid capillary monolithic column (IMSN-C18 monolithic column) was successfully prepared, and the effects of fabrication conditions (e.g. concentration of intact mesoporous silica nanoparticle, polycondensation temperature, content of vinyltrimethoxysilane and stearyl methacrylate) on the structures of the IMSN-C18 monolithic column were studied in detail. The IMSN-C18 hybrid monolithic column possessed uniform morphology, good mechanical and pH stability (pH 1.1-11), which was applied to the separations of alkyl benzenes, polycyclic aromatic hydrocarbons (PAHs), as well as proteins. The minimum plate height of 10.5 μm (corresponding to 95000 N m -1 ) for butylbenzene and high reproducibility were achieved. The analysis of tryptic digest of bovine serum albumin (BSA) was carried out on the IMSN-C18 monolithic column by cLC coupled mass spectrometry (cLC-MS/MS), with the protein sequence coverage of 87.5% for BSA, demonstrating its potential application in proteomics.

Simple analytical model for low-frequency frequency-modulation noise of monolithic tunable lasers.

PubMed

Huynh, Tam N; Ó Dúill, Seán P; Nguyen, Lim; Rusch, Leslie A; Barry, Liam P

2014-02-10

We employ simple analytical models to construct the entire frequency-modulation (FM)-noise spectrum of tunable semiconductor lasers. Many contributions to the laser FM noise can be clearly identified from the FM-noise spectrum, such as standard Weiner FM noise incorporating laser relaxation oscillation, excess FM noise due to thermal fluctuations, and carrier-induced refractive index fluctuations from stochastic carrier generation in the passive tuning sections. The contribution of the latter effect is identified by noting a correlation between part of the FM-noise spectrum with the FM-modulation response of the passive sections. We pay particular attention to the case of widely tunable lasers with three independent tuning sections, mainly the sampled-grating distributed Bragg reflector laser, and compare with that of a distributed feedback laser. The theoretical model is confirmed with experimental measurements, with the calculations of the important phase-error variance demonstrating excellent agreement.

The Impact of Software Structure and Policy on CPU and Memory System Performance

DTIC Science & Technology

1994-05-01

Mach 3.0 is that Ultrix is a monolithic or integrated system, and Mach 3.0 is a microkernel or kernelized system. In a monolithic system, all system...services are implemented in a single system context, the monolithic kernel . In a microkernel system such as Mach 3.0, primitive abstractions such as...separate protection domain as a server. Many current operating system text books discuss microkernel and monolithic kernel design. (See [17, 73, 77].) The

Monolithically integrated active optical devices. [with application in optical communication

NASA Technical Reports Server (NTRS)

Ballantyne, J.; Wagner, D. K.; Kushner, B.; Wojtzcuk, S.

1981-01-01

Considerations relevant to the monolithic integration of optical detectors, lasers, and modulators with high speed amplifiers are discussed. Some design considerations for representative subsystems in the GaAs-AlGaAs and GaInAs-InP materials systems are described. Results of a detailed numerical design of an electro-optical birefringent filter for monolithic integration with a laser diode is described, and early experimental results on monolithic integration of broadband MESFET amplifiers with photoconductive detectors are reported.

Computer aided design of monolithic microwave and millimeter wave integrated circuits and subsystems

NASA Astrophysics Data System (ADS)

Ku, Walter H.; Gang, Guan-Wan; He, J. Q.; Ichitsubo, I.

1988-05-01

This final technical report presents results on the computer aided design of monolithic microwave and millimeter wave integrated circuits and subsystems. New results include analytical and computer aided device models of GaAs MESFETs and HEMTs or MODFETs, new synthesis techniques for monolithic feedback and distributed amplifiers and a new nonlinear CAD program for MIMIC called CADNON. This program incorporates the new MESFET and HEMT model and has been successfully applied to the design of monolithic millimeter-wave mixers.

Monolithic porous magnesium silicide.

PubMed

Hayati-Roodbari, N; Berger, R J F; Bernardi, J; Kinge, S; Hüsing, N; Elsaesser, M S

2017-07-11

Macroporous magnesium silicide monoliths were successfully prepared by a two-step synthesis procedure. The reaction of gaseous magnesium vapor with macro-/mesoporous silicon, which was generated from hierarchically organized meso-/macroporous silica by a magnesiothermic reduction reaction, resulted in monolithic magnesium silicide with a cellular, open macroporous structure. By adjusting the reaction conditions, such as experimental set-up, temperature and time, challenges namely loss of porosity or phase purity of Mg 2 Si were addressed and monolithic magnesium silicide with a cellular network builtup was obtained.

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

PubMed

Karenga, Samuel; El Rassi, Ziad

2011-04-01

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

Black Hole Paradoxes

NASA Astrophysics Data System (ADS)

Joshi, Pankaj S.; Narayan, Ramesh

2016-10-01

We propose here that the well-known black hole paradoxes such as the information loss and teleological nature of the event horizon are restricted to a particular idealized case, which is the homogeneous dust collapse model. In this case, the event horizon, which defines the boundary of the black hole, forms initially, and the singularity in the interior of the black hole at a later time. We show that, in contrast, gravitational collapse from physically more realistic initial conditions typically leads to the scenario in which the event horizon and space-time singularity form simultaneously. We point out that this apparently simple modification can mitigate the causality and teleological paradoxes, and also lends support to two recently suggested solutions to the information paradox, namely, the ‘firewall’ and ‘classical chaos’ proposals.

Key variables influencing patterns of lava dome growth and collapse

NASA Astrophysics Data System (ADS)

Husain, T.; Elsworth, D.; Voight, B.; Mattioli, G. S.; Jansma, P. E.

2013-12-01

Lava domes are conical structures that grow by the infusion of viscous silicic or intermediate composition magma from a central volcanic conduit. Dome growth can be characterized by repeated cycles of growth punctuated by collapse, as the structure becomes oversized for its composite strength. Within these cycles, deformation ranges from slow long term deformation to sudden deep-seated collapses. Collapses may range from small raveling failures to voluminous and fast-moving pyroclastic flows with rapid and long-downslope-reach from the edifice. Infusion rate and magma rheology together with crystallization temperature and volatile content govern the spatial distribution of strength in the structure. Solidification, driven by degassing-induced crystallization of magma leads to the formation of a continuously evolving frictional talus as a hard outer shell. This shell encapsulates the cohesion-dominated soft ductile core. Here we explore the mechanics of lava dome growth and failure using a two-dimensional particle-dynamics model. This meshless model follows the natural evolution of a brittle carapace formed by loss of volatiles and rheological stiffening and avoids difficulties of hour-glassing and mesh-entangelment typical in meshed models. We test the fidelity of the model against existing experimental and observational models of lava dome growth. The particle-dynamics model follows the natural development of dome growth and collapse which is infeasible using simple analytical models. The model provides insight into the triggers that lead to the transition in collapse mechasnism from shallow flank collapse to deep seated sector collapse. Increase in material stiffness due to decrease in infusion rate results in the transition of growth pattern from endogenous to exogenous. The material stiffness and strength are strongly controlled by the magma infusion rate. Increase in infusion rate decreases the time available for degassing induced crystallization leading to a transition in the growth pattern, while a decrease in infusion rate results in larger crystals causing the material to stiffen leading to formation of spines. Material stiffness controls the growth direction of the viscous plug in the lava dome interior. Material strength and stiffness controled by rate of infusion influence lava dome growth more significantly than coefficient of frictional of the talus.

Quantum Zeno Effect in the Measurement Problem

NASA Technical Reports Server (NTRS)

Namiki, Mikio; Pasaczio, Saverio

1996-01-01

Critically analyzing the so-called quantum Zeno effect in the measurement problem, we show that observation of this effect does not necessarily mean experimental evidence for the naive notion of wave-function collapse by measurement (the simple projection rule). We also examine what kind of limitation the uncertainty relation and others impose on the observation of the quantum Zeno effect.

Monolithic microfluidic concentrators and mixers

DOEpatents

Frechet, Jean M.; Svec, Frantisek; Yu, Cong; Rohr, Thomas

2005-05-03

Microfluidic devices comprising porous monolithic polymer for concentration, extraction or mixing of fluids. A method for in situ preparation of monolithic polymers by in situ initiated polymerization of polymer precursors within microchannels of a microfluidic device and their use for solid phase extraction (SPE), preconcentration, concentration and mixing.

Monolithic exploding foil initiator

DOEpatents

Welle, Eric J; Vianco, Paul T; Headley, Paul S; Jarrell, Jason A; Garrity, J. Emmett; Shelton, Keegan P; Marley, Stephen K

2012-10-23

A monolithic exploding foil initiator (EFI) or slapper detonator and the method for making the monolithic EFI wherein the exploding bridge and the dielectric from which the flyer will be generated are integrated directly onto the header. In some embodiments, the barrel is directly integrated directly onto the header.

Preparation of polyhedral oligomeric silsesquioxane based imprinted monolith.

PubMed

Li, Fang; Chen, Xiu-Xiu; Huang, Yan-Ping; Liu, Zhao-Sheng

2015-12-18

Polyhedral oligomeric silsesquioxane (POSS) was successfully applied, for the first time, to prepare imprinted monolithic column with high porosity and good permeability. The imprinted monolithic column was synthesized with a mixture of PSS-(1-Propylmethacrylate)-heptaisobutyl substituted (MA 0702), naproxon (template), 4-vinylpyridine, and ethylene glycol dimethacrylate, in ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIM]BF4). The influence of synthesis parameters on the retention factor and imprinting effect, including the amount of MA 0702, the ratio of template to monomer, and the ratio of monomer to crosslinker, was investigated. The greatest imprinting factor on the imprinted monolithic column prepared with MA 0702 was 22, about 10 times higher than that prepared in absence of POSS. The comparisons between MIP monoliths synthesized with POSS and without POSS were made in terms of permeability, column efficiency, surface morphology and pore size distribution. In addition, thermodynamic and Van Deemter analysis were used to evaluate the POSS-based MIP monolith. Copyright © 2015 Elsevier B.V. All rights reserved.

Methacrylate-bonded covalent-organic framework monolithic columns for high performance liquid chromatography.

PubMed

Liu, Li-Hua; Yang, Cheng-Xiong; Yan, Xiu-Ping

2017-01-06

Covalent-organic frameworks (COFs) are a newfangled class of intriguing microporous materials. Considering their unique properties, COFs should be promising as packing materials for high performance liquid chromatography (HPLC). However, the irregular shape and sub-micrometer size of COFs synthesized via the traditional methods render the main obstacles for the application of COFs in HPLC. Herein, we report the preparation of methacrylate-bonded COF monolithic columns for HPLC to overcome the above obstacles. The prepared COF bonded monolithic columns not only show good homogeneity and permeability, but also give high column efficiency, good resolution and precision for HPLC separation of small molecules including polycyclic aromatic hydrocarbons, phenols, anilines, nonsteroidal anti-inflammatory drugs and benzothiophenes. Compared with the bare polymer monolithic column, the COF bonded monolithic columns show enhanced hydrophobic, π-π and hydrogen bond interactions in reverse phase HPLC. The results reveal the great potential of COF bonded monoliths for HPLC and COFs in separation sciences. Copyright © 2016 Elsevier B.V. All rights reserved.

Aspartic acid incorporated monolithic columns for affinity glycoprotein purification.

PubMed

Armutcu, Canan; Bereli, Nilay; Bayram, Engin; Uzun, Lokman; Say, Rıdvan; Denizli, Adil

2014-02-01

Novel aspartic acid incorporated monolithic columns were prepared to efficiently affinity purify immunoglobulin G (IgG) from human plasma. The monolithic columns were synthesised in a stainless steel HPLC column (20 cm × 5 mm id) by in situ bulk polymerisation of N-methacryloyl-L-aspartic acid (MAAsp), a polymerisable derivative of L-aspartic acid, and 2-hydroxyethyl methacrylate (HEMA). Monolithic columns [poly(2-hydroxyethyl methacrylate-N-methacryloyl-L-aspartic acid) (PHEMAsp)] were characterised by swelling studies, Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The monolithic columns were used for IgG adsorption/desorption from aqueous solutions and human plasma. The IgG adsorption depended on the buffer type, and the maximum IgG adsorption from aqueous solution in phosphate buffer was 0.085 mg/g at pH 6.0. The monolithic columns allowed for one-step IgG purification with a negligible capacity decrease after ten adsorption-desorption cycles. Copyright © 2013 Elsevier B.V. All rights reserved.

Preparation of polyhedral oligomeric silsesquioxane based hybrid monoliths by ring-opening polymerization for capillary LC and CEC.

PubMed

Lin, Hui; Zhang, Zhenbin; Dong, Jing; Liu, Zhongshan; Ou, Junjie; Zou, Hanfa

2013-09-01

A new organic-inorganic hybrid monolith was prepared by the ring-opening polymerization of octaglycidyldimethylsilyl polyhedral oligomeric silsesquioxane (POSS) with 1,4-butanediamine (BDA) using 1-propanol, 1,4-butanediol, and PEG 10,000 as a porogenic system. Benefiting from the moderate phase separation process, the resulting poly(POSS-co-BDA) hybrid monolith possessed a uniform microstructure and exhibited excellent performance in chromatographic applications. Neutral, acidic, and basic compounds were successfully separated on the hybrid monolith in capillary LC (cLC), and high column efficiencies were achieved in all of the separations. In addition, as the amino groups could generate a strong EOF, the hybrid monolith was also applied in CEC for the separation of neutral and polar compounds, and a satisfactory performance was obtained. These results demonstrate that the poly(POSS-co-BDA) hybrid monolith is a good separation media in chromatographic separations of various types of compounds by both cLC and CEC. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Cast-to-shape electrokinetic trapping medium

DOEpatents

Shepodd, Timothy J.; Franklin, Elizabeth; Prickett, Zane T.; Artau, Alexander

2004-08-03

A three-dimensional microporous polymer network material, or monolith, cast-to-shape in a microchannel. The polymer monolith, produced by a phase separation process, is capable of trapping and retaining charged protein species from a mixture of charged and uncharged species under the influence of an applied electric field. The retained charged protein species are released from the porous polymer monolith by a pressure driven flow in the substantial absence of the electric field. The pressure driven flow is independent of direction and thus neither means to reverse fluid flow nor a multi-directional flow field is required, a single flow through the porous polymer monolith can be employed, in contrast to prior art systems. The monolithic polymer material produced by the invention can function as a chromatographic medium. Moreover, by virtue of its ability to retain charged protein species and quantitatively release the retained species the porous polymer monolith can serve as a means for concentrating charged protein species from, for example, a dilute solution.

Cast-to-shape electrokinetic trapping medium

DOEpatents

Shepodd, Timothy J [Livermore, CA; Franklin, Elizabeth [Rolla, MO; Prickett, Zane T [Golden, CO; Artau, Alexander [Pleasanton, CA

2006-05-30

A three-dimensional microporous polymer network material, or monolith, cast-to-shape in a microchannel. The polymer monolith, produced by a phase separation process, is capable of trapping and retaining charged protein species from a mixture of charged and uncharged species under the influence of an applied electric field. The retained charged protein species are released from the porous polymer monolith by a pressure driven flow in the substantial absence of the electric field. The pressure driven flow is independent of direction and thus neither means to reverse fluid flow nor a multi-directional flow field is required, a single flow through the porous polymer monolith can be employed, in contrast to prior art systems. The monolithic polymer material produced by the invention can function as a chromatographic medium. Moreover, by virtue of its ability to retain charged protein species and quantitatively release the retained species the porous polymer monolith can serve as a means for concentrating charged protein species from, for example, a dilute solution.

Chromatographic selectivity of poly(alkyl methacrylate-co-divinylbenzene) monolithic columns for polar aromatic compounds by pressure-driven capillary liquid chromatography.

PubMed

Lin, Shu-Ling; Wang, Chih-Chieh; Fuh, Ming-Ren

2016-10-05

In this study, divinylbenzene (DVB) was used as the cross-linker to prepare alkyl methacrylate (AlMA) monoliths for incorporating π-π interactions between the aromatic analytes and AlMA-DVB monolithic stationary phases in capillary LC analysis. Various AlMA/DVB ratios were investigated to prepare a series of 30% AlMA-DVB monolithic stationary phases in fused-silica capillaries (250-μm i.d.). The physical properties (such as porosity, permeability, and column efficiency) of the synthesized AlMA-DVB monolithic columns were investigated for characterization. Isocratic elution of phenol derivatives was first employed to evaluate the suitability of the prepared AlMA-DVB columns for small molecule separation. The run-to-run (0.16-1.20%, RSD; n = 3) and column-to-column (0.26-2.95%, RSD; n = 3) repeatabilities on retention times were also examined using the selected AlMA-DVB monolithic columns. The π-π interactions between the aromatic ring and the DVB-based stationary phase offered better recognition on polar analytes with aromatic moieties, which resulted in better separation resolution of aromatic analytes on the AlMA-DVB monolithic columns. In order to demonstrate the capability of potential environmental and/or food safety applications, eight phenylurea herbicides with single benzene ring and seven sulfonamide antibiotics with polyaromatic moieties were analyzed using the selected AlMA-DVB monolithic columns. Copyright © 2016. Published by Elsevier B.V.

Monolithic column based on a poly(glycidyl methacrylate-co-4-vinylphenylboronic acid-co-ethylene dimethacrylate) copolymer for capillary liquid chromatography of small molecules and proteins.

PubMed

Lin, Zian; Huang, Hui; Sun, Xiaobo; Lin, Yao; Zhang, Lan; Chen, Guonan

2012-07-13

A new polymer monolith with three modes of reverse-phase, hydrophilic and cation-exchange interaction was synthesized in 100 μm i.d. fused-silica capillary by in situ polymerization procedure. The pre-polymerization mixture consisted of glycidyl methacrylate (GMA) and 4-vinylphenylboronic acid (VPBA) as bifunctional monomers, ethylene dimethacrylate (EDMA) as crosslinker, 1,4-butanediol (BDO) and diethylene glycol (DEG) as binary porogenic solvents, and azobisisobutyronitrile (AIBN) as initiator. The resulting poly(GMA-co-VPBA-co-EDMA) monolith showed a relatively homogeneous monolithic structure, good permeability and mechanical stability. Different ratios of monomers and porogens were used for optimizing the properties of monolithic column. The column performance was assessed by the separation of a series of neutral solutes, charge solutes, phenols and anilines. Compared with poly(GMA-co-EDMA) monolith, the proposed monolith exhibited more flexible adjustment of selectivity in terms of hydrophobic, hydrophilic, as well as cation-exchange interaction in the same chromatographic conditions. High column efficiencies for benzene derivatives with 70,000-102,000 theoretical plates/m could be obtained at a linear velocity of 0.265 mm/s. The run-to-run, column-to-column, and batch-to-batch repeatabilities of the retention times were less than 8.23%. Additionally, the purposed monolith was also applied to efficient separation of alkaloids and proteins for demonstrating its potential in biomolecule separation. Crown Copyright © 2012. Published by Elsevier B.V. All rights reserved.

Iminodiacetic acid functionalised organopolymer monoliths: application to the separation of metal cations by capillary high-performance chelation ion chromatography.

PubMed

Moyna, Áine; Connolly, Damian; Nesterenko, Ekaterina; Nesterenko, Pavel N; Paull, Brett

2013-03-01

Lauryl methacrylate-co-ethylene dimethacrylate monoliths were polymerised within fused silica capillaries and subsequently photo-grafted with varying amounts of glycidyl methacrylate (GMA). The grafted monoliths were then further modified with iminodiacetic acid (IDA), resulting in a range of chelating ion-exchange monoliths of increasing capacity. The IDA functional groups were attached via ring opening of the epoxy group on the poly(GMA) structure. Increasing the amount of attached poly(GMA), via photo-grafting with increasing concentrations of GMA, from 15 to 35%, resulted in a proportional and controlled increase in the complexation capacity of the chelating monoliths. Scanning capacitively coupled contactless conductivity detection (sC(4)D) was used to characterise and verify homogenous distribution of the chelating ligand along the length of the capillaries non-invasively. Chelation ion chromatographic separations of selected transition and heavy metals were carried out, with retention factor data proportional to the concentration of grafted poly(GMA). Average peak efficiencies of close to 5,000 N/m were achieved, with the isocratic separation of Na, Mg(II), Mn(II), Co(II), Cd(II) and Zn(II) possible on a 250-mm-long monolith. Multiple monolithic columns produced to the same recipes gave RSD data for retention factors of <15% (averaged for several metal ions). The monolithic chelating ion-exchanger was applied to the separation of alkaline earth and transition metal ions spiked in natural and potable waters.

Facile preparation of SiO2/TiO2 composite monolithic capillary column and its application in enrichment of phosphopeptides.

PubMed

Wang, Shao-Ting; Wang, Meng-Ya; Su, Xin; Yuan, Bi-Feng; Feng, Yu-Qi

2012-09-18

A novel SiO(2)/TiO(2) composite monolithic capillary column was prepared by sol-gel technology and successfully applied to enrich phosphopeptides as a metal oxide affinity chromatography (MOAC) material. For the monolith preparation, tetramethoxysilane (TMOS) and tetrabutoxytitanium (TBOT) were used as silica and titania source, respectively, and glycerol was introduced to attenuate the activity of titanium precursor, which provided a mild synthetic condition. The prepared monolith was characterized by energy dispersive X-ray spectroscopy (EDX) and X-ray diffraction (XRD). The results revealed an approximate 1/2 molar ratio of titanium to silica as well as an atom-scale homogeneity in the framework. The scanning electron microscopy (SEM) results demonstrated an excellent anchorage between the column and the inner capillary wall, and nitrogen adsorption-desorption experiments showed a bimodal porosity with a narrow mesopore distribution around 3.6 nm. The prepared monolith was then applied for selective enrichment of phosphopeptides from the digestion mixture of phosphoproteins and bovine serum albumin (BSA) as well as human blood serum, nonfat milk, and egg white using an in-tube solid phase microextraction (SPME) system. Our results showed that SiO(2)/TiO(2) composite monolithic capillary column could efficiently enrich the phosphopeptides from complex matrixes. To the best of our knowledge, this is the first attempt for preparing the silica-metal composite monolithic capillary column, which offers the promising application of the monolith on phosphoproteomics study.

The 3D pore structure and fluid dynamics simulation of macroporous monoliths: High permeability due to alternating channel width.

PubMed

Jungreuthmayer, Christian; Steppert, Petra; Sekot, Gerhard; Zankel, Armin; Reingruber, Herbert; Zanghellini, Jürgen; Jungbauer, Alois

2015-12-18

Polymethacrylate-based monoliths have excellent flow properties. Flow in the wide channel interconnected with narrow channels is theoretically assumed to account for favorable permeability. Monoliths were cut into 898 slices in 50nm distances and visualized by serial block face scanning electron microscopy (SBEM). A 3D structure was reconstructed and used for the calculation of flow profiles within the monolith and for calculation of pressure drop and permeability by computational fluid dynamics (CFD). The calculated and measured permeabilities showed good agreement. Small channels clearly flowed into wide and wide into small channels in a repetitive manner which supported the hypothesis describing the favorable flow properties of these materials. This alternating property is also reflected in the streamline velocity which fluctuated. These findings were corroborated by artificial monoliths which were composed of regular (interconnected) cells where narrow cells followed wide cells. In the real monolith and the artificial monoliths with interconnected flow channels similar velocity fluctuations could be observed. A two phase flow simulation showed a lateral velocity component, which may contribute to the transport of molecules to the monolith wall. Our study showed that the interconnection of small and wide pores is responsible for the excellent pressure flow properties. This study is also a guide for further design of continuous porous materials to achieve good flow properties. Copyright © 2015 The Authors. Published by Elsevier B.V. All rights reserved.

A Delayed Choice Quantum Eraser Explained by the Transactional Interpretation of Quantum Mechanics

NASA Astrophysics Data System (ADS)

Fearn, H.

2016-01-01

This paper explains the delayed choice quantum eraser of Kim et al. (A delayed choice quantum eraser, 1999) in terms of the transactional interpretation (TI) of quantum mechanics by Cramer (Rev Mod Phys 58:647, 1986, The quantum handshake, entanglement, nonlocality and transactions, 1986). It is kept deliberately mathematically simple to help explain the transactional technique. The emphasis is on a clear understanding of how the instantaneous "collapse" of the wave function due to a measurement at a specific time and place may be reinterpreted as a relativistically well-defined collapse over the entire path of the photon and over the entire transit time from slit to detector. This is made possible by the use of a retarded offer wave, which is thought to travel from the slits (or rather the small region within the parametric crystal where down-conversion takes place) to the detector and an advanced counter wave traveling backward in time from the detector to the slits. The point here is to make clear how simple the transactional picture is and how much more intuitive the collapse of the wave function becomes if viewed in this way. Also, any confusion about possible retro-causal signaling is put to rest. A delayed choice quantum eraser does not require any sort of backward in time communication. This paper makes the point that it is preferable to use the TI over the usual Copenhagen interpretation for a more intuitive understanding of the quantum eraser delayed choice experiment. Both methods give exactly the same end results and can be used interchangeably.

Creating deep soil core monoliths: Beyond the solum

USDA-ARS?s Scientific Manuscript database

Soil monoliths serve as useful teaching aids in the study of the Earth’s critical zone where rock, soil, water, air, and organisms interact. Typical monolith preparation has so far been confined to the 1 to 2-m depth of the solum. Critical ecosystem services provided by soils include materials from ...

Method of fabricating a monolithic solid oxide fuel cell

DOEpatents

Minh, N.Q.; Horne, C.R.

1994-03-01

In a two-step densifying process of making a monolithic solid oxide fuel cell, a limited number of anode-electrolyte-cathode cells separated by an interconnect layer are formed and partially densified. Subsequently, the partially densified cells are stacked and further densified to form a monolithic array. 10 figures.

Method of fabricating a monolithic solid oxide fuel cell

DOEpatents

Minh, Nguyen Q.; Horne, Craig R.

1994-01-01

In a two-step densifying process of making a monolithic solid oxide fuel cell, a limited number of anode-electrolyte-cathode cells separated by an interconnect layer are formed and partially densified. Subsequently, the partially densified cells are stacked and further densified to form a monolithic array.

75 FR 7931 - Airworthiness Directives; Airbus Model A380-841, -842, and -861 Airplanes

Federal Register 2010, 2011, 2012, 2013, 2014

2010-02-23

... addition, delamination has been observed within the monolithic Carbon Fibre Reinforced Plastic (CFRP... observed within the monolithic Carbon Fibre Reinforced Plastic (CFRP) structure around the pivot support... monolithic Carbon Fibre Reinforced Plastic (CFRP) structure around the pivot support-ring. This condition, if...

Recent advances in monolithic columns for protein and peptide separation by capillary liquid chromatography.

PubMed

Liang, Yu; Zhang, Lihua; Zhang, Yukui

2013-03-01

Capillary liquid chromatography (cLC) has great potential for protein and peptide separation, with advantages of high efficiency, high resolution, low sample consumption, and high sensitivity when coupled with mass spectrometry. In recent years, monoliths have been widely used as the stationary phases for capillary columns, owing to easy preparation, high permeability, fast mass transfer, and low backpressure. This review summarizes recent advances (2007-2012) in monolithic columns for protein and peptide separation by cLC. After a brief introduction on the preparation of monolithic capillary columns, the emphasis of this review is focused on the recent application of such columns for protein and peptide separation by cLC. Furthermore, the challenges and potential hot points of monolithic capillary columns in the future are discussed.

Specially Treated Aramid Fiber Stabilized Gel-Emulsions: Preparation of Porous Polymeric Monoliths and Highly Efficient Removing of Airborne HCHO.

PubMed

Liu, Jianfei; Chen, Xiangli; Wang, Pei; Fu, Xuwei; Liu, Kaiqiang; Fang, Yu

2017-08-01

Porous polymeric monoliths with densities as low as ≈0.060 g cm -3 are prepared in a gel-emulsion template way, of which the stabilizer employed is a newly discovered acidified aramid fiber that is so efficient that 0.05% (w/v, accounts for continuous phase) is enough to gel the system. The porous monoliths as obtained can be dried at ambient conditions, avoiding energy-consuming processes. Importantly, the monoliths show selective adsorption to HCHO, and the corresponding adsorption capacity (M6) is ≈2700 mg g -1 , the best result that is reported until now. More importantly, the monoliths can be reused after drying. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Preparation of convection interaction media isobutyl disc monolithic column and its application to purification of secondary alcohol dehydrogenase and alcohol oxidase.

PubMed

Isobe, Kimiyasu; Kawakami, Yoshimitsu

2007-03-09

A convection interaction media (trade name CIM, BIA Separation, Ljubljana, Slovenia) isobutyl monolithic disc was prepared by incubating a CIM epoxy monolithic disc with isobutylamine, and it was then applied to the purification of secondary alcohol dehydrogenase (S-ADH) and primary alcohol oxidase (P-AOD). Both enzymes were adsorbed on this column and eluted with high purity. Thus, S-ADH was purified to an electrophoretically homogeneous state by four column chromatographies using CIM DEAE-8 and CIM C4-8 tube monolithic columns, blue-Sepharose column and CIM isobutyl disc monolithic column. P-AOD was also purified to an electrophoretically homogeneous state by three column chromatographies of CIM DEAE-8 tube, CIM C4-8 tube and CIM isobutyl disc columns.

Development and application of a high-performance liquid chromatography method using monolithic columns for the analysis of ecstasy tablets.

PubMed

Mc Fadden, Kim; Gillespie, John; Carney, Brian; O'Driscoll, Daniel

2006-07-07

A rapid and selective HPLC method using monolithic columns was developed for the separation and quantification of the principal amphetamines in ecstasy tablets. Three monolithic (Chromolith RP18e) columns of different lengths (25, 50 and 100 mm) were assessed. Validation studies including linearity, selectivity, precision, accuracy and limit of detection and quantification were carried out using the Chromolith SpeedROD, RP-18e, 50 mm x 4.6 mm column. Column backpressure and van Deemter plots demonstrated that monolithic columns provide higher efficiency at higher flow rates when compared to particulate columns without the loss of peak resolution. Application of the monolithic column to a large number of ecstasy tablets seized in Ireland ensured its suitability for the routine analysis of ecstasy tablets.

Influence of porogen nature on the kinetic and potential efficiencies of divinylbenzene-based monolithic sorbents in gas chromatography

NASA Astrophysics Data System (ADS)

Korolev, A. A.; Shiryaeva, V. E.; Popova, T. P.; Kanat'eva, A. Yu.; Kurganov, A. A.

2015-02-01

It has been shown that using Poppe curves for characterization of monolithic sorbents makes it possible to optimize conditions for both the synthesis of monoliths intended for high-speed analysis and achievement of the best separation efficiency. The influence of the nature of a porogen on the kinetic efficiency of monolithic sorbents in high-pressure gas chromatography has been considered. It has been found that the nature of the porogen alcohol determines to a considerable extent the structure of the monolith and its kinetic efficiency. The sorbents prepared with the use of octanol-1 and dodecanol-1 have shown the best kinetic characteristics; however, minimal HETP values have been observed for the columns prepared using hexanol-1 as a porogen.

Fabrication of an ionic-liquid-based polymer monolithic column and its application in the fractionation of proteins from complex biosamples.

PubMed

Zhang, Doudou; Zhang, Qian; Bai, Ligai; Han, Dandan; Liu, Haiyan; Yan, Hongyuan

2018-05-01

An ionic-liquid-based polymer monolithic column was synthesized by free radical polymerization within the confines of a stainless-steel column (50 mm × 4.6 mm id). In the processes, ionic liquid and stearyl methacrylate were used as dual monomers, ethylene glycol dimethacrylate as the cross-linking agent, and polyethylene glycol 200 and isopropanol as co-porogens. Effects of the prepolymerization solution components on the properties of the resulting monoliths were studied in detail. Scanning electron microscopy, nitrogen adsorption-desorption measurements, and mercury intrusion porosimetry were used to investigate the morphology and pore size distribution of the prepared monoliths, which showed that the homemade ionic-liquid-based monolith column possessed a relatively uniform macropore structure with a total macropore specific surface area of 44.72 m 2 /g. Compared to a non-ionic-liquid-based monolith prepared under the same conditions, the ionic-liquid-based monolith exhibited excellent selectivity and high performance for separating proteins from complex biosamples, such as egg white, snailase, bovine serum albumin digest solution, human plasma, etc., indicating promising applications in the fractionation and analysis of proteins from the complex biosamples in proteomics research. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Ionic liquid-regenerated macroporous cellulose monolith: Fabrication, characterization and its protein chromatography.

PubMed

Du, Kaifeng

2017-04-21

Macroporous cellulose monolith as chromatographic support was successfully fabricated from an ionic liquid dissolved cellulose solution by an emulsification method and followed by the cross-linking reaction and DEAE modification. With the physical characterization, the cellulose monolith featured by both the interconnected macropores in range of 0.5-2.5μm and the diffusion pores centered at about 10nm. Given the bimodal pore system, the monolith possessed the specific surface area of 36.4m 2 g -1 and the column permeability of about 7.45×10 -14 m 2 . After the DEAE modification, the anion cellulose monolith was evaluated for its chromatography performances. It demonstrated that the static and dynamic adsorption capacity of BSA reached about 66.7mgmL -1 and 43.9mgmL -1 at 10% breakthrough point, respectively. The results were comparable to other chromatographic adsorbent. In addition, the proteins mixture with different pI was well separated at high flow velocity (611.0cmh -1 ) and high protein recovery (over 97%), proving the macroporous cellulose monolith had excellent separation performance. In this way, the prepared cellulose monolith with bimodal pores system is expected for the potential application in high-speed chromatography. Copyright © 2017 Elsevier B.V. All rights reserved.

Design of catalytic monoliths for closed-cycle carbon dioxide lasers

NASA Technical Reports Server (NTRS)

Herz, R. K.; Guinn, K.; Goldblum, S.; Noskowski, E.

1989-01-01

Pulsed carbon dioxide (CO2) lasers have many applications in aeronautics, space research, weather monitoring and other areas. Full exploitation of the potential of these lasers in hampered by the dissociation of CO2 that occurs during laser operation. The development of closed-cycle CO2 lasers requires active CO-O2 recombination (CO oxidation) catalyst and design methods for implementation of catalysts in CO2 laser systems. A monolith catalyst section model and associated design computer program, LASCAT, are presented to assist in the design of a monolith catalyst section of a closed cycle CO2 laser system. Using LASCAT,the designer is able to specify a number of system parameters and determine the monolith section performance. Trade-offs between the catalyst activity, catalyst dimensions, monolith dimensions, pressure drop, O2 conversion, and other variables can be explored and adjusted to meet system design specifications. An introduction describes a typical closed-cycle CO2 system, and indicates some advantages of a closed cycle laser system over an open cycle system and some advantages of monolith support over other types of supports. The development and use of a monolith catalyst model is presented. The results of a design study and a discussion of general design rules are given.

Influence of the linking spacer length and type on the enantioseparation ability of β-cyclodextrin functionalized monoliths.

PubMed

Guo, Jialiang; Xiao, Yuan; Lin, Yuanjing; Zhang, Qiaoxuan; Chang, Yiqun; Crommen, Jacques; Jiang, Zhengjin

2016-05-15

In order to investigate the effect of the linking spacer on the enantioseparation ability of β-cyclodextrin (β-CD) functionalized polymeric monoliths, three β-CD-functionalized organic polymeric monoliths with different spacer lengths were prepared by using three amino-β-CDs, i.e. mono-6-amino-6-deoxy-β-CD, mono-6-ethylenediamine-6-deoxy-β-CD, mono-6-hexamethylenediamine-6-deoxy-β-CD, as starting materials. These amino-β-CDs reacted with glycidyl methacrylate to produce functional monomers which were then copolymerized with ethylene dimethacrylate. The enantioseparation ability of the three monoliths was evaluated using 14 chiral acidic compounds, including mandelic acid derivatives, nonsteroidal anti-inflammatory drugs, N-derivatized amino acids, and chiral herbicides under optimum chromatographic conditions. Notably, the poly(GMA-NH2-β-CD-co-EDMA) column provides higher enantioresolution and enantioselectivity than the poly(GMA-EDA-β-CD-co-EDMA) and poly(GMA-HDA-β-CD-co-EDMA) columns for most tested chiral analytes. Furthermore, the enantioseparation performance of triazole-linker containing monoliths was compared to that of ethylenediamine-linker containing monoliths. The results indicate that the enantioselectivity of β-CD monolithic columns is strongly related to the length and type of spacer tethering β-CD to the polymeric support. Copyright © 2016 Elsevier B.V. All rights reserved.

Construction of hierarchically porous monoliths from covalent organic frameworks (COFs) and their application for bisphenol A removal.

PubMed

Liu, Zhongshan; Wang, Hongwei; Ou, Junjie; Chen, Lianfang; Ye, Mingliang

2018-05-11

Subject to synthetic conditions, covalent organic frameworks (COFs) are usually in powder form. Herein, taking an azine-linked COF as an example, detailed characterizations indicated that accessible aldehyde groups and hydrazine groups (CNNH 2 , 88 μmol g -1 ) concurrently existed on its surface. Intrigued by such feature, we have developed an approach based on ring-opening polymerization to shape COF powder into monoliths. The crystallinity and micropore of COF in monoliths were well remained, meanwhile, the ring-opening polymerization remarkably generated macropores ranging from 0.43 to 3.51 μm, indicating a hierarchically porous structure. The BET surface area of resultant monoliths with different COF mass fractions of 16%, 28% and 43% ranged from 105 to 281 m 2  g -1 . Due to the π-π interaction and hydrogen bond interaction, COF-based monoliths exhibited strong retention and rapid adsorption for bisphenol A (BPA) in aqueous medium. When 29 mL BPA solution (22.8 mg L -1 ) passed through COF-based monolith (28%), the adsorption capacity was up to 61.3 mg g -1 . Furthermore, the COF-based monolith demonstrated excellent cycle use for catalyzing Suzuki-Miyaura coupling reaction after being coordinated with palladium acetate. Copyright © 2018 Elsevier B.V. All rights reserved.

In situ polymerization of monolith based on poly(Triallyl Isocyanurate-co-trimethylolpropane triacrylate) and its application in high-performance liquid chromatography.

PubMed

Zhong, Jing; Bai, Ligai; Qin, Junxiao; Wang, Jiafei; Hao, Mengbei; Yang, Gengliang

2015-04-01

A novel organic monolithic stationary phase was prepared for high-performance liquid chromatography (HPLC) by in situ copolymerization. In which, triallyl isocyanurate (TAIC) and trimethylolpropane triacrylate (TMPTA) in a binary porogenic solvent consisting of polyethylene glycol 200 and 1, 2-propanediol were used. The resultant monoliths with different column properties (e.g., morphology and pressure) were optimized by adjusting the ratio of TMPTA/TAIC and the composition of porogenic solvent. The resulting poly(TAIC-co-TMPTA) monolith showed a relatively homogeneous structure, good permeability and mechanical stability. The chemical group of the monolith was assayed by the infrared spectra method, the morphology of monolithic material was studied by scanning electron microscopy and the pore size distribution was determined by a mercury porosimeter. A series of small molecules were used to evaluate the column performance in terms of hydrophobic mode. At an optimized flow rate of 1.0 mL min(-1), the theoretical plate number of analyte was >15,000 plates m(-1). These applications demonstrated that the monoliths could be successfully used as the stationary phase in conjunction with HPLC to separate small molecules from the mixture. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Recognition of oxytocin by capillary electrochromatography with monolithic tetrapeptide-imprinted polymer used as the stationary phase.

PubMed

Zheng, Chao; Liu, Zhaosheng; Gao, Ruyu; Zhang, Lihua; Zhang, Yukui

2007-07-01

Using YPLG (Tyr-Pro-Leu-Gly), a tetrapeptide, as the template, an imprinted monolithic column was prepared and applied to the selective recognition of oxytocin based on the epitope approach and capillary electrochromatography (CEC). By optimizing the polymerization solution in terms of functional monomer, cross-linking reagent, porogen, and imprinted template via CEC evaluations of synthesized columns, an imprinted monolith with good recognition capacity (the imprinting factors for YPLG and oxytocin were 4.499 and 4.013, respectively) and high column efficiency (theoretical plates for YPLG and oxytocin were 22,995 plates/m and 16,952 plates/m, respectively) was achieved. In addition, the effects of various experimental parameters on the recognition of oxytocin, including the organic modifier content, the buffer concentration, and the pH value, were studied systematically. Furthermore, a mixture of oxytocin and other proteins was analyzed using this monolithic CEC column, and oxytocin was eluted much more slowly than other large biomolecules, which demonstrated the high selective recognition ability of such an imprinted monolith for oxytocin with PLG (Pro-Leu-Gly) as the epitope. Figure Separation of a mixture of oxytocin, BSA, bovine hemoglobin, ovalbumin, and lysozyme on the open column, the blank monolithic column, and the monolithic YPLG-imprinted column.

Design of Simple Landslide Monitoring System

NASA Astrophysics Data System (ADS)

Meng, Qingjia; Cai, Lingling

2018-01-01

The simple landslide monitoring system is mainly designed for slope, collapse body and surface crack. In the harsh environment, the dynamic displacement data of the disaster body is transmitted to the terminal acquisition system in real time. The main body of the system adopt is PIC32MX795F512. This chip is to realize low power design, wakes the system up through the clock chip, and turns on the switching power supply at set time, which makes the wireless transmission module running during the interval to ensure the maximum battery consumption, so that the system can be stable long term work.

Pyroclastic Flow Generated Tsunami Waves Detected by CALIPSO Borehole Strainmeters at Soufriere Hills, Montserrat During Massive Dome Collapse: Numerical Simulations and Observations

NASA Astrophysics Data System (ADS)

van Boskirk, E. J.; Voight, B.; Watts, P.; Widiwijayanti, C.; Mattioli, G. S.; Elsworth, D.; Hidayat, D.; Linde, A.; Malin, P.; Neuberg, J.; Sacks, S.; Shalev, E.; Sparks, R. J.; Young, S. R.

2004-12-01

The July 12-13, 2003 eruption (dome collapse plus explosions) of Soufriere Hills Volcano in Montserrat, WI, is the largest historical lava dome collapse with ˜120 million cubic meters of the dome lost. Pyroclastic flows entered the sea at 18:00 AST 12 July at the Tar River Valley (TRV) and continued until the early hours of 13 July. Low-amplitude tsunamis were reported at Antigua and Guadaloupe soon after the dome collapse. At the time of eruption, four CALIPSO borehole-monitoring stations were in the process of being installed, and three very-broad-band Sacks-Evertson dilatometers were operational and recorded the event at 50 sps. The strongest strain signals were recorded at the Trants site, 5 km north of the TRV entry zone, suggesting tsunami waves >1 m high. Debris strandlines closer to TRV recorded runup heights as much as 8 m. We test the hypothesis that the strain signal is related to tsunami waves generated by successive pyroclastic flows induced during the dome collapse. Tsunami simulation models have been generated using GEOWAVE, which uses simple physics to recreate waves generated by idealized pyroclastic flows entering the sea at TRV. Each simulation run contains surface wave amplitude gauges located in key positions to the three borehole sites. These simulated wave amplitudes and periods are compared quantitatively with the data recorded by the dilatometers and with field observations of wave runup, to elucidate the dynamics of pyroclastic flow tsunami genesis and its propagation in shallow ocean water.

Difficulty in tracheal extubation followed by tracheal collapse after balloon dilatation for tracheal stenosis therapy: A case report.

PubMed

Li, Nana; Zhu, Linjia; Sun, Jie; Pan, Yinbing; Gao, Mei

2018-06-01

Tracheobronchomalacia (TBM) refers to the weakening trachea or the trachea loss of structural integrity of airway cartilaginous structures. It causes tracheal stenosis, resulting in significantly high rates of mortality. Bronchoplasty by high-pressure balloon dilation under general anesthesia is a simple but effective and safe method to treat tracheobronchial stenosis. However, recurrent postoperative dyspnea after extubation due to tracheal collapse is still a challenge for anesthetists. A 52-year-old man weighing 72 kg was scheduled for balloon dilatation surgery under general anesthesia because of breathing difficulties caused by tracheal stenosis. His previous medical history included rheumatoid arthritis, obstructive sleep apnea syndrome (OSAS), chronic bronchitis and a history of tracheal intubation. Laryngeal computerized tomography confirmed the stenosis at the level of thyroid gland. The tracheal collapse after balloon dilatation for tracheal stenosis therapy. Postoperatively, the patient presented with more serious and repetitive symptoms of dyspnea after extubation when compared to that before treatment. So, we had to re-insert the laryngeal mask airway (LMA), and exclude some anesthesia-associated factors, such as laryngospasm, bronchospasm and so on. After a series of treatments, we ultimately found the cause in time (the airway collapsed), and succeeded in tracheal extubation after the stent was inserted. The patient recovered well and reported high satisfaction with anesthesia management. In such an emergency even, the anesthesiologist should take valuable treatments to ensure the patient's effective ventilation. If the anesthesia-related factors can be eliminated, tracheomalacia or airway collapse should be considered whenever dyspnea occurs in the patients who unexpectedly fail to be extubated.

A Classical Phase Space Framework For the Description of Supercooled Liquids and an Apparent Universal Viscosity Collapse

NASA Astrophysics Data System (ADS)

Weingartner, Nicholas; Pueblo, Chris; Nogueira, Flavio; Kelton, Kenneth; Nussinov, Zohar

A fundamental understanding of the phenomenology of the metastable supercooled liquid state remains elusive. Two of the most pressing questions in this field are how to describe the temperature dependence of the viscosity, and determine whether or not the dynamical behaviors are universal. To address these questions, we have devised a simple first-principles classical phase space description of supercooled liquids that (along with a complementary quantum approach) predicts a unique functional form for the viscosity which relies on only a single parameter. We tested this form for 45 liquids of all types and fragilities, and have demonstrated that it provides a statistically significant fit to all liquids. Additionally, by scaling the viscosity of all studied liquids using the single parameter, we have observed a complete collapse of the data of all 45 liquids to a single scaling curve over 16 decades, suggesting an underlying universality in the dynamics of supercooled liquids. In this talk I will outline the basic approach of our model, as well as demonstrate the quality of the model performance and collapse of the data.

Airborne Astronomy Program

NASA Technical Reports Server (NTRS)

Butner, Harold M.

1999-01-01

Our understanding about the inter-relationship between the collapsing cloud envelope and the disk has been greatly altered. While the dominant star formation models invoke free fall collapse and r(sup -1.5) density profile, other star formation models are possible. These models invoke either different cloud starting conditions or the mediating effects of magnetic fields to alter the cloud geometry during collapse. To test these models, it is necessary to understand the envelope's physical structure. The discovery of disks, based on millimeter observations around young stellar objects, however makes a simple interpretation of the emission complicated. Depending on the wavelength, the disk or the envelope could dominate emission from a star. In addition, the discovery of planets around other stars has made understanding the disks in their own right quite important. Many star formation models predict disks should form naturally as the star is forming. In many cases, the information we derive about disk properties depends implicitly on the assumed envelope properties. How to understand the two components and their interaction with each other is a key problem of current star formation.

Concentrated Solutions of Single-Chain Nanoparticles: A Simple Model for Intrinsically Disordered Proteins under Crowding Conditions.

PubMed

Moreno, Angel J; Lo Verso, Federica; Arbe, Arantxa; Pomposo, José A; Colmenero, Juan

2016-03-03

By means of large-scale computer simulations and small-angle neutron scattering (SANS), we investigate solutions of single-chain nanoparticles (SCNPs), covering the whole concentration range from infinite dilution to melt density. The analysis of the conformational properties of the SCNPs reveals that these synthetic nano-objects share basic ingredients with intrinsically disordered proteins (IDPs), as topological polydispersity, generally sparse conformations, and locally compact domains. We investigate the role of the architecture of the SCNPs in their collapse behavior under macromolecular crowding. Unlike in the case of linear macromolecules, which experience the usual transition from self-avoiding to Gaussian random-walk conformations, crowding leads to collapsed conformations of SCNPs resembling those of crumpled globules. This behavior is already found at volume fractions (about 30%) that are characteristic of crowding in cellular environments. The simulation results are confirmed by the SANS experiments. Our results for SCNPs--a model system free of specific interactions--propose a general scenario for the effect of steric crowding on IDPs: collapse from sparse conformations at high dilution to crumpled globular conformations in cell environments.

Distribution of nuclei in equilibrium stellar matter from the free-energy density in a Wigner-Seitz cell

NASA Astrophysics Data System (ADS)

Grams, G.; Giraud, S.; Fantina, A. F.; Gulminelli, F.

2018-03-01

The aim of the present study is to calculate the nuclear distribution associated at finite temperature to any given equation of state of stellar matter based on the Wigner-Seitz approximation, for direct applications in core-collapse simulations. The Gibbs free energy of the different configurations is explicitly calculated, with special care devoted to the calculation of rearrangement terms, ensuring thermodynamic consistency. The formalism is illustrated with two different applications. First, we work out the nuclear statistical equilibrium cluster distribution for the Lattimer and Swesty equation of state, widely employed in supernova simulations. Secondly, we explore the effect of including shell structure, and consider realistic nuclear mass tables from the Brussels-Montreal Hartree-Fock-Bogoliubov model (specifically, HFB-24). We show that the whole collapse trajectory is dominated by magic nuclei, with extremely spread and even bimodal distributions of the cluster probability around magic numbers, demonstrating the importance of cluster distributions with realistic mass models in core-collapse simulations. Simple analytical expressions are given, allowing further applications of the method to any relativistic or nonrelativistic subsaturation equation of state.

All together now: Analogies between chimera state collapses and epileptic seizures

NASA Astrophysics Data System (ADS)

Andrzejak, Ralph G.; Rummel, Christian; Mormann, Florian; Schindler, Kaspar

2016-03-01

Conceptually and structurally simple mathematical models of coupled oscillator networks can show a rich variety of complex dynamics, providing fundamental insights into many real-world phenomena. A recent and not yet fully understood example is the collapse of coexisting synchronous and asynchronous oscillations into a globally synchronous motion found in networks of identical oscillators. Here we show that this sudden collapse is promoted by a further decrease of synchronization, rather than by critically high synchronization. This strikingly counterintuitive mechanism can be found also in nature, as we demonstrate on epileptic seizures in humans. Analyzing spatiotemporal correlation profiles derived from intracranial electroencephalographic recordings (EEG) of seizures in epilepsy patients, we found a pronounced decrease of correlation at the seizure onsets. Applying our findings in a closed-loop control scheme to models of coupled oscillators in chimera states, we succeed in both provoking and preventing outbreaks of global synchronization. Our findings not only advance the understanding of networks of coupled dynamics but can open new ways to control them, thus offering a vast range of potential new applications.

Top-down solid-phase fabrication of nanoporous cadmium oxide architectures.

PubMed

Yu, Haidong; Wang, Deshen; Han, Ming-Yong

2007-02-28

In this article, we have demonstrated one-step solid-phase transformation from high-quality cadmium carbonate microcrystals into highly nanoporous cadmium oxide. The high crystal quality of cadmium carbonate is critical for the successful fabrication of porous nanoarchitectures with predetermined morphology and well-controlled internal structure. This novel strategy has a good potential to prepare nanoporous materials at a large scale by using perfect monolithic carbonate crystals, and it is also useful to synthesize different nanoporous materials on metal-oxide-coated substrates. Meanwhile, this simple thermal transformation of cadmium carbonate into porous structures has further been extended to convert calcium carbonate into such porous structures.

Hardware implementation of an adaptive resonance theory (ART) neural network using compensated operational amplifiers

NASA Astrophysics Data System (ADS)

Ho, Ching S.; Liou, Juin J.; Georgiopoulos, Michael; Christodoulou, Christos G.

1994-03-01

This paper presents an analog circuit design and implementation for an adaptive resonance theory neural network architecture called the augmented ART1 neural network (AART1-NN). Practical monolithic operational amplifiers (Op-Amps) LM741 and LM318 are selected to implement the circuit, and a simple compensation scheme is developed to adjust the Op-Amp electrical characteristics to meet the design requirement. A 7-node prototype circuit has been designed and verified using the Pspice circuit simulator run on a Sun workstation. Results simulated from the AART1-NN circuit using the LM741, LM318, and ideal Op-Amps are presented and compared.

Spacecraft Conceptual Design for the 8-Meter Advanced Technology Large Aperture Space Telescope (ATLAST)

NASA Technical Reports Server (NTRS)

Hopkins, Randall C.; Capizzo, Peter; Fincher, Sharon; Hornsby, Linda S.; Jones, David

2010-01-01

The Advanced Concepts Office at Marshall Space Flight Center completed a brief spacecraft design study for the 8-meter monolithic Advanced Technology Large Aperture Space Telescope (ATLAST-8m). This spacecraft concept provides all power, communication, telemetry, avionics, guidance and control, and thermal control for the observatory, and inserts the observatory into a halo orbit about the second Sun-Earth Lagrange point. The multidisciplinary design team created a simple spacecraft design that enables component and science instrument servicing, employs articulating solar panels for help with momentum management, and provides precise pointing control while at the same time fast slewing for the observatory.

One-Pot Route towards Active TiO2 Doped Hierarchically Porous Cellulose: Highly Efficient Photocatalysts for Methylene Blue Degradation

PubMed Central

Sun, Xiaoxia; Wang, Kunpeng; Shu, Yu; Zou, Fangdong; Zhang, Boxing; Sun, Guangwu; Uyama, Hiroshi; Wang, Xinhou

2017-01-01

In this study, novel photocatalyst monolith materials were successfully fabricated by a non-solvent induced phase separation (NIPS) technique. By adding a certain amount of ethyl acetate (as non-solvent) into a cellulose/LiCl/N,N-dimethylacetamide (DMAc) solution, and successively adding titanium dioxide (TiO2) nanoparticles (NPs), cellulose/TiO2 composite monoliths with hierarchically porous structures were easily formed. The obtained composite monoliths possessed mesopores, and two kinds of macropores. Scanning Electron Microscope (SEM), Energy Dispersive Spectroscopy (EDS), Fourier Transform Infrared Spectroscopy (FT-IR), X-ray Diffraction (XRD), Brunauer-Emmett-Teller (BET), and Ultraviolet-visible Spectroscopy (UV-Vis) measurements were adopted to characterize the cellulose/TiO2 composite monolith. The cellulose/TiO2 composite monoliths showed high efficiency of photocatalytic activity in the decomposition of methylene blue dye, which was decomposed up to 99% within 60 min under UV light. Moreover, the composite monoliths could retain 90% of the photodegradation efficiency after 10 cycles. The novel NIPS technique has great potential for fabricating recyclable photocatalysts with highly efficiency. PMID:28772734

Monolithic fiber laser oscillator with record high power

NASA Astrophysics Data System (ADS)

Yang, Baolai; Shi, Chen; Zhang, Hanwei; Ye, Qing; Pi, Haoyang; Tao, Rumao; Wang, Xiaolin; Ma, Pengfei; Leng, Jinyong; Chen, Zilun; Zhou, Pu; Xu, Xiaojun; Chen, Jinbao; Liu, Zejin

2018-07-01

With an increasing output power, the power scaling of monolithic fiber laser oscillators faces the severe limitations of stimulated Raman scattering (SRS) and the transverse mode instability (TMI) effect. In this work, we report a high power monolithic fiber laser oscillator with a maximum output power of 5.2 kW, which is realized with a trade-off design between the SRS and TMI. The monolithic fiber laser oscillator is constructed with ytterbium-doped fiber with a core/inner cladding diameter of 25/400 µm and corresponding home-made FBG. High-power 915 nm laser diodes are employed as a pump source and are distributed in a bidirectional-pump configuration. By optimizing the bidirectional pump proportion, the monolithic fiber laser oscillator is scaled up to 5.2 kW with a slope efficiency of ~63%. Operating at 5.2 kW, the intensity of the Raman stokes light is ~22 dB below the signal laser and the beam quality (M2-factor) is ~2.2. To the best of our knowledge, this is a record high power for monolithic fiber laser oscillators.

Enantioseparation on cellulose dimethylphenylcarbamate-modified zirconia monolithic columns by reversed-phase capillary electrochromatography.

PubMed

Kumar, Avvaru Praveen; Park, Jung Hag

2010-06-25

This work reports the preparation of monolithic zirconia chiral columns for separation of enantiomeric compounds by capillary electrochromatography (CEC). Using sol-gel technology, a porous monolith having interconnected globular-like structure with through-pores is synthesized in the capillary column as a first step in the synthesis of monolithic zirconia chiral capillary columns. In the second step, the surface of the monolith is modified by coating with cellulose tris(3,5-dimethylphenylcarbamate) (CDMPC) as the chiral stationary phase to obtain a chiral column (CDMPCZM). The process of the preparation of the zirconia monolithic capillary column was investigated by varying the concentrations of the components of the sol solution including polyethylene glycol, water and acetic acid. CDMPCZM is mechanically stable and no bubble formation was detected with the applied current of up to 30 microA. The enantioseparation behavior of the CDMPCZM columns was investigated by separating a set of 10 representative chiral compounds by varying the applied voltage and pH and organic composition of the aqueous organic mobile phases. Copyright 2010 Elsevier B.V. All rights reserved.

Application of a Fast Separation Method for Anti-diabetics in Pharmaceuticals Using Monolithic Column: Comparative Study With Silica Based C-18 Particle Packed Column.

PubMed

Hemdan, A; Abdel-Aziz, Omar

2018-04-01

Run time is a predominant factor in HPLC for quality control laboratories especially if there is large number of samples have to be analyzed. Working at high flow rates cannot be attained with silica based particle packed column due to elevated backpressure issues. The use of monolithic column as an alternative to traditional C-18 column was tested for fast separation of pharmaceuticals, where the results were very competitive. The performance comparison of both columns was tested for separation of anti-diabetic combination containing Metformin, Pioglitazone and Glimepiride using Gliclazide as an internal standard. Working at high flow rates with less significant backpressure was obtained with the monolithic column where the run time was reduced from 6 min in traditional column to only 1 min in monolithic column with accepted resolution. The structure of the monolith contains many pores which can adapt the high flow rate of the mobile phase. Moreover, peak symmetry and equilibration time were more efficient with monolithic column.

Relating monolithic and granular leaching from contaminated soil treated with different cementitious binders.

PubMed

Kogbara, Reginald B; Al-Tabbaa, Abir; Stegemann, Julia A

2013-01-01

This work employed a clayey, silty, sandy gravel contaminated with a mixture of metals (Cd, Cu, Pb, Ni and Zn) and diesel. The contaminated soil was treated with 5 and 10% dosages of different cementitious binders. The binders include Portland cement, cement-fly ash, cement-slag and lime-slag mixtures. Monolithic leaching from the treated soils was evaluated over a 64-day period alongside granular leachability of 49- and 84-day old samples. Surface wash-off was the predominant leaching mechanism for monolithic samples. In this condition, with data from different binders and curing ages combined, granular leachability as a function of monolithic leaching generally followed degrees 4 and 6 polynomial functions. The only exception was for Cu, which followed the multistage dose-response model. The relationship between both leaching tests varied with the type of metal, curing age/residence time of monolithic samples in the leachant, and binder formulation. The results provide useful design information on the relationship between leachability of metals from monolithic forms of S/S treated soils and the ultimate leachability in the eventual breakdown of the stabilized/solidified soil.

Purification and concentration of mycobacteriophage D29 using monolithic chromatographic columns.

PubMed

Liu, Keyang; Wen, Zhanbo; Li, Na; Yang, Wenhui; Hu, Lingfei; Wang, Jie; Yin, Zhe; Dong, Xiaokai; Li, Jinsong

2012-12-01

Bacteriophages are used widely in many fields, and phages with high purity and infectivity are required. Convective interaction media (CIM) methacrylate monoliths were used for the purification of mycobacteriophage D29. The lytic phages D29 from bacterial lysate were purified primarily by polyethylene glycol 8000 or ammonium sulphate, and then the resulting phages were passed through the CIM monolithic columns for further purification. After the whole purification process, more than 99% of the total proteins were removed irrespective which primary purification method was used. The total recovery rates of viable phages were around 10-30%. Comparable results were obtained when the purification method was scaled-up from a 0.34 mL CIM DEAE (diethylamine) monolithic disk to an 8 mL CIM DEAE monolithic column. Copyright © 2012 Elsevier B.V. All rights reserved.

Monolithic solid-state lasers for spaceflight

NASA Astrophysics Data System (ADS)

Krainak, Michael A.; Yu, Anthony W.; Stephen, Mark A.; Merritt, Scott; Glebov, Leonid; Glebova, Larissa; Ryasnyanskiy, Aleksandr; Smirnov, Vadim; Mu, Xiaodong; Meissner, Stephanie; Meissner, Helmuth

2015-02-01

A new solution for building high power, solid state lasers for space flight is to fabricate the whole laser resonator in a single (monolithic) structure or alternatively to build a contiguous diffusion bonded or welded structure. Monolithic lasers provide numerous advantages for space flight solid-state lasers by minimizing misalignment concerns. The closed cavity is immune to contamination. The number of components is minimized thus increasing reliability. Bragg mirrors serve as the high reflector and output coupler thus minimizing optical coatings and coating damage. The Bragg mirrors also provide spectral and spatial mode selection for high fidelity. The monolithic structure allows short cavities resulting in short pulses. Passive saturable absorber Q-switches provide a soft aperture for spatial mode filtering and improved pointing stability. We will review our recent commercial and in-house developments toward fully monolithic solid-state lasers.

Identifying mechanisms for superdiffusive dynamics in cell trajectories

NASA Astrophysics Data System (ADS)

Passucci, Giuseppe; Brasch, Megan; Henderson, James; Manning, M. Lisa

Self-propelled particle (SPP) models have been used to explore features of active matter such as motility-induced phase separation, jamming, and flocking, and are often used to model biological cells. However, many cells exhibit super-diffusive trajectories, where displacements scale faster than t 1 / 2 in all directions, and these are not captured by traditional SPP models. We extract cell trajectories from image stacks of mouse fibroblast cells moving on 2D substrates and find super-diffusive mean-squared displacements in all directions across varying densities. Two SPP model modifications have been proposed to capture super-diffusive dynamics: Levy walks and heterogeneous motility parameters. In mouse fibroblast cells displacement probability distributions collapse when time is rescaled by a power greater than 1/2, which is consistent with Levy walks. We show that a simple SPP model with heterogeneous rotational noise can also generate a similar collapse. Furthermore, a close examination of statistics extracted directly from cell trajectories is consistent with a heterogeneous mobility SPP model and inconsistent with a Levy walk model. Our work demonstrates that a simple set of analyses can distinguish between mechanisms for anomalous diffusion in active matter.

Structural Solutions for Low-Cost Bamboo Frames: Experimental Tests and Constructive Assessments

PubMed Central

Sassu, Mauro; De Falco, Anna; Giresini, Linda; Puppio, Mario Lucio

2016-01-01

Experimental tests and constructive assessments are presented for a simple bamboo framed structure with innovative low-cost and low technology joints, specifically conceived for small buildings in developing countries. Two full scale one-storey bamboo frames have been designed by using the simplest joints solution among three different tested typologies. The entire building process is based on low-technology and natural materials: bamboo canes, wooden cylinders, plywood plates and canapé rods. The first full scale specimen (Unit A) is a one-storey single deck truss structure subjected to monotonic collapse test; the second full scale specimen (Unit B) is a one-storey double deck truss structure used to evaluate the construction time throughout assembling tests. The first full scale specimen showed ductility in collapse and ease in strengthening; the second one showed remarkable ease and speed in assembling structural elements. Finally several constructive solutions are suggested for the design of simple one-storey buildings; they are addressed to four purposes (housing, school, chapel, health center) by the composition of the proposed full scale bamboo frames. Ease of use and maintenance with a low level of technology contribute to application in developing countries although not exclusively. PMID:28773472

A novel mixed phospholipid functionalized monolithic column for early screening of drug induced phospholipidosis risk.

PubMed

Zhao, XiangLong; Chen, WeiJia; Liu, ZhengHua; Guo, JiaLiang; Zhou, ZhengYin; Crommen, Jacques; Moaddel, Ruin; Jiang, ZhengJin

2014-11-07

Drug-induced phospholipidosis (PLD) is characterized by the excessive accumulation of phospholipids, resulting in multilamellar vesicle structure within lysosomes. In the present study, a novel mixed phospholipid functionalized monolithic column was developed for the first time through a facile one-step co-polymerization approach. The phospholipid composition of the monolith can be adjusted quantitatively and accurately to mimic the mixed phospholipid environment of different biomembranes on a solid matrix. The mixed phospholipid functionalized monolith as a promising immobilized artificial membrane technique was used to study drug-phospholipid interaction. Scanning electron microscopy, elemental analysis, FT-IR spectra, ζ-potential analysis and micro-HPLC were carried out to characterize the physicochemical properties and separation performance of the monolith. Mechanism studies revealed that both hydrophobic and electrostatic interactions play an important role in the retention of analytes. The ratio of their contributions to retention can be easily manipulated by adjusting the composition of the mixed phospholipids, in order to better mimic the interaction between drugs and cell membrane. The obtained mixed phospholipid functionalized monolithic columns were applied to the screening of drug-induced PLD potency. Data from 79 drugs on the market demonstrated that the chromatographic hydrophobicity index referring to the mixed phospholipid functionalized monolith at pH 7.4 (CHI IAM7.4) for the selected drugs were highly correlated with the drug-induced PLD potency data obtained from other in vivo or in vitro assays. Moreover, the effect of the acidic phospholipid phosphatidylserine proportion on prediction accuracy was also investigated. The monolith containing 20% phosphatidylserine and 80% phosphatidylcholine exhibited the best prediction ability for the drug-induced PLD potency of the tested compounds. This research has led to the successful development of a novel and facile approach to prepare a mixed phospholipids functionalized monolith, which offers a reliable, cost-effective and high-throughput screening tool for early prediction of the PLD potency of drug candidates. Copyright © 2014 Elsevier B.V. All rights reserved.

On the Physics of Fizziness: How Bubble Bursting Controls Droplets Ejection

NASA Astrophysics Data System (ADS)

Seon, Thomas; Ghabache, Elisabeth; Antkowiak, Arnaud; Josserand, Christophe

2014-11-01

Either in a champagne glass or at the oceanic scales, the tiny bubbles rising at the surface burst in ejecting myriads of droplets. Focusing on the bubble bursting jet, prelude for these aerosols, we propose a simple scaling for the jet velocity, we unravel experimentally the intricate roles of bubble shape, capillary waves and liquid properties, and we demonstrate that droplets ejection can be tuned by changing the liquid properties. In particular, as capillary waves are shown to always evolve into a self-similar collapsing cavity, faster and smaller droplets can be produced by sheltering this collapse from remnant ripples using damping action of viscosity. These results pave the road to the characterization and control of the bursting bubble aerosols. Applications to champagne aroma diffusion will be discussed.

Highly crosslinked polymeric monoliths for reversed-phase capillary liquid chromatography of small molecules.

PubMed

Liu, Kun; Tolley, H Dennis; Lee, Milton L

2012-03-02

Seven crosslinking monomers, i.e., 1,3-butanediol dimethacrylate (1,3-BDDMA), 1,4-butanediol dimethacrylate (1,4-BDDMA), neopentyl glycol dimethacrylate (NPGDMA), 1,5-pentanediol dimethacrylate (1,5-PDDMA), 1,6-hexanediol dimethacrylate (1,6-HDDMA), 1,10-decanediol dimethacrylate (1,10-DDDMA), and 1,12-dodecanediol dimethacrylate (1,12-DoDDMA), were used to synthesize highly cross-linked monolithic capillary columns for reversed-phase liquid chromatography (RPLC) of small molecules. Dodecanol and methanol were chosen as "good" and "poor" porogenic solvents, respectively, for these monoliths, and were investigated in detail to provide insight into the selection of porogen concentration using 1,12-DoDDMA. Isocratic elution of alkylbenzenes at a flow rate of 300 nL/min was conducted for all of the monoliths. Gradient elution of alkylbenzenes and alkylparabens provided high resolution separations. Optimized monoliths synthesized from all seven crosslinking monomers showed high permeability. Several of the monoliths demonstrated column efficiencies in excess of 50,000 plates/m. Monoliths with longer alkyl-bridging chains showed very little shrinking or swelling in solvents of different polarities. Column preparation was highly reproducible; the relative standard deviation (RSD) values (n=3) for run-to-run and column-to-column were less than 0.25% and 1.20%, respectively, based on retention times of alkylbenzenes. Copyright © 2012 Elsevier B.V. All rights reserved.

Direct preparation of a graphene oxide modified monolith in a glass syringe as a solid-phase extraction cartridge for the extraction of quaternary ammonium alkaloids from Chinese patent medicine.

PubMed

Liang, Xiaojing; Wang, Licheng; Wang, Shuai; Li, Yijing; Guo, Yong

2017-11-01

Packed cartridges have been widely used in solid-phase extraction. However, there are still some drawbacks, such as they are blocked easily and the method is time-consuming. In view of the advantages of monoliths, a monolithic extraction material has been directly synthesized in a glass syringe without any gap between the monolith and syringe inner wall. The monolithic syringe was modified with graphene oxide by loading graphene oxide dispersion onto it. The content of graphene oxide and the surface topography of the monolith have been evaluated by elemental analysis and scanning electron microscopy, respectively, which confirmed the successful modification. This prepared graphene oxide-modified monolithic syringe was directly used as a traditional solid-phase extraction cartridge. As expected, it shows good permeability and excellent capability for the extraction of quaternary ammonium alkaloids. The sample loading velocity (1-6 mL/min) does not affect the recovery. Under the optimal conditions, good linearities (R = 0.9992-0.9998) were obtained for five quaternary ammonium alkaloids, and the limits of detection and quantification were 0.5-1 and 1-2 μg/L, respectively. The proposed method was successfully applied for the analysis of quaternary ammonium alkaloids in Chinese patent medicine. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Fabrication of mesoporous polymer monolith: a template-free approach.

PubMed

Okada, Keisuke; Nandi, Mahasweta; Maruyama, Jun; Oka, Tatsuya; Tsujimoto, Takashi; Kondoh, Katsuyoshi; Uyama, Hiroshi

2011-07-14

Mesoporous polyacrylonitrile (PAN) monolith has been fabricated by a template-free approach using the unique affinity of PAN towards a water/dimethyl sulfoxide (DMSO) mixture. A newly developed Thermally Induced Phase Separation Technique (TIPS) has been used to obtain the polymer monoliths and their microstructures have been controlled by optimizing the concentration and cooling temperature.

Low noise InP-based MMIC receivers for W-band

NASA Technical Reports Server (NTRS)

Leonard, Regis F.

1991-01-01

A program to develop a monolithic W-band low noise amplifier (a critical element in any W-band communications, sensors, or radar application) is described. Goals of the program include a completely monolithic low noise amplifier, less than a 3.5 dB noise figure, and a monolithic mixer suitable for integration with the LNA.

Monolithically integrated absolute frequency comb laser system

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

Wanke, Michael C.

2016-07-12

Rather than down-convert optical frequencies, a QCL laser system directly generates a THz frequency comb in a compact monolithically integrated chip that can be locked to an absolute frequency without the need of a frequency-comb synthesizer. The monolithic, absolute frequency comb can provide a THz frequency reference and tool for high-resolution broad band spectroscopy.

Synthesis of monolithic graphene – graphite integrated electronics

PubMed Central

Park, Jang-Ung; Nam, SungWoo; Lee, Mi-Sun; Lieber, Charles M.

2013-01-01

Encoding electronic functionality into nanoscale elements during chemical synthesis has been extensively explored over the past decade as the key to developing integrated nanosystems1 with functions defined by synthesis2-6. Graphene7-12 has been recently explored as a two-dimensional nanoscale material, and has demonstrated simple device functions based on conventional top-down fabrication13-20. However, the synthetic approach to encoding electronic functionality and thus enabling an entire integrated graphene electronics in a chemical synthesis had not previously been demonstrated. Here we report an unconventional approach for the synthesis of monolithically-integrated electronic devices based on graphene and graphite. Spatial patterning of heterogeneous catalyst metals permits the selective growth of graphene and graphite, with controlled number of graphene layers. Graphene transistor arrays with graphitic electrodes and interconnects were formed from synthesis. These functional, all-carbon structures were transferrable onto a variety of substrates. The integrated transistor arrays were used to demonstrate real-time, multiplexed chemical sensing, and more significantly, multiple carbon layers of the graphene-graphite device components were vertically assembled to form a three-dimensional flexible structure which served as a top-gate transistor array. These results represent a substantial progress towards encoding electronic functionality via chemical synthesis and suggest future promise for one-step integration of graphene-graphite based electronics. PMID:22101813

Synthesis of monolithic graphene-graphite integrated electronics.

PubMed

Park, Jang-Ung; Nam, SungWoo; Lee, Mi-Sun; Lieber, Charles M

2011-11-20

Encoding electronic functionality into nanoscale elements during chemical synthesis has been extensively explored over the past decade as the key to developing integrated nanosystems with functions defined by synthesis. Graphene has been recently explored as a two-dimensional nanoscale material, and has demonstrated simple device functions based on conventional top-down fabrication. However, the synthetic approach to encoding electronic functionality and thus enabling an entire integrated graphene electronics in a chemical synthesis had not previously been demonstrated. Here we report an unconventional approach for the synthesis of monolithically integrated electronic devices based on graphene and graphite. Spatial patterning of heterogeneous metal catalysts permits the selective growth of graphene and graphite, with a controlled number of graphene layers. Graphene transistor arrays with graphitic electrodes and interconnects were formed from the synthesis. These functional, all-carbon structures were transferable onto a variety of substrates. The integrated transistor arrays were used to demonstrate real-time, multiplexed chemical sensing and more significantly, multiple carbon layers of the graphene-graphite device components were vertically assembled to form a three-dimensional flexible structure which served as a top-gate transistor array. These results represent substantial progress towards encoding electronic functionality through chemical synthesis and suggest the future promise of one-step integration of graphene-graphite based electronics.

Tunable color parallel tandem organic light emitting devices with carbon nanotube and metallic sheet interlayers

NASA Astrophysics Data System (ADS)

Oliva, Jorge; Papadimitratos, Alexios; Desirena, Haggeo; De la Rosa, Elder; Zakhidov, Anvar A.

2015-11-01

Parallel tandem organic light emitting devices (OLEDs) were fabricated with transparent multiwall carbon nanotube sheets (MWCNT) and thin metal films (Al, Ag) as interlayers. In parallel monolithic tandem architecture, the MWCNT (or metallic films) interlayers are an active electrode which injects similar charges into subunits. In the case of parallel tandems with common anode (C.A.) of this study, holes are injected into top and bottom subunits from the common interlayer electrode; whereas in the configuration of common cathode (C.C.), electrons are injected into the top and bottom subunits. Both subunits of the tandem can thus be monolithically connected functionally in an active structure in which each subunit can be electrically addressed separately. Our tandem OLEDs have a polymer as emitter in the bottom subunit and a small molecule emitter in the top subunit. We also compared the performance of the parallel tandem with that of in series and the additional advantages of the parallel architecture over the in-series were: tunable chromaticity, lower voltage operation, and higher brightness. Finally, we demonstrate that processing of the MWCNT sheets as a common anode in parallel tandems is an easy and low cost process, since their integration as electrodes in OLEDs is achieved by simple dry lamination process.

Seismic performance of interior precast concrete beam-column connections with T-section steel inserts under cyclic loading

NASA Astrophysics Data System (ADS)

Ketiyot, Rattapon; Hansapinyo, Chayanon

2018-04-01

An experimental investigation was conducted to study the performance of precast beam-column concrete connections using T-section steel inserts into the concrete beam and joint core, under reversed cyclic loading. Six 2/3-scale interior beam-column subassemblies, one monolithic concrete specimen and five precast concrete specimens were tested. One precast specimen was a simple connection for a gravity load resistant design. Other precast specimens were developed with different attributes to improve their seismic performance. The test results showed that the performance of the monolithic specimen M1 represented ductile seismic behavior. Failure of columns and joints could be prevented, and the failure of the frame occurred at the flexural plastic hinge formation at the beam ends, close to the column faces. For the precast specimens, the splitting crack along the longitudinal lapped splice was a major failure. The precast P5 specimen with double steel T-section inserts showed better seismic performance compared to the other precast models. However, the dowel bars connected to the steel inserts were too short to develop a bond. The design of the precast concrete beams with lap splice is needed for longer lap lengths and should be done at the beam mid span or at the low flexural stress region.

Detection and Recovery of Palladium, Gold and Cobalt Metals from the Urban Mine Using Novel Sensors/Adsorbents Designated with Nanoscale Wagon-wheel-shaped Pores.

PubMed

El-Safty, Sherif A; Shenashen, Mohamed A; Sakai, Masaru; Elshehy, Emad; Halada, Kohmei

2015-12-06

Developing low-cost, efficient processes for recovering and recycling palladium, gold and cobalt metals from urban mine remains a significant challenge in industrialized countries. Here, the development of optical mesosensors/adsorbents (MSAs) for efficient recognition and selective recovery of Pd(II), Au(III), and Co(II) from urban mine was achieved. A simple, general method for preparing MSAs based on using high-order mesoporous monolithic scaffolds was described. Hierarchical cubic Ia3d wagon-wheel-shaped MSAs were fabricated by anchoring chelating agents (colorants) into three-dimensional pores and micrometric particle surfaces of the mesoporous monolithic scaffolds. Findings show, for the first time, evidence of controlled optical recognition of Pd(II), Au(III), and Co(II) ions and a highly selective system for recovery of Pd(II) ions (up to ~95%) in ores and industrial wastes. Furthermore, the controlled assessment processes described herein involve evaluation of intrinsic properties (e.g., visual signal change, long-term stability, adsorption efficiency, extraordinary sensitivity, selectivity, and reusability); thus, expensive, sophisticated instruments are not required. Results show evidence that MSAs will attract worldwide attention as a promising technological means of recovering and recycling palladium, gold and cobalt metals.

Validated RP-HPLC/DAD Method for the Quantification of Insect Repellent Ethyl 2-Aminobenzoate in Membrane-Moderated Matrix Type Monolithic Polymeric Device.

PubMed

Islam, Johirul; Zaman, Kamaruz; Chakrabarti, Srijita; Sharma Bora, Nilutpal; Mandal, Santa; Pratim Pathak, Manash; Srinivas Raju, Pakalapati; Chattopadhyay, Pronobesh

2017-07-01

A simple, accurate and sensitive reversed-phase high-performance liquid chromatographic (RP-HPLC) method has been developed for the estimation of ethyl 2-aminobenzoate (EAB) in a matrix type monolithic polymeric device and validated as per the International Conference on Harmonization guidelines. The analysis was performed isocratically on a ZORBAX Eclipse plus C18 analytical column (250 × 4.4 mm, 5 μm) and a diode array detector (DAD) using acetonitrile and water (75:25 v/v) as the mobile phase by keeping the flow-rate constant at 1.0 mL/min. Determination of EAB was not interfered in the presence of excipients. Inter- and intra-day relative standard deviations were not higher than 2%. Mean recovery was between 98.7 and 101.3%. Calibration curve was linear in the concentration range of 0.5-10 µg/mL. Limits of detection and quantification were 0.19 and 0.60 µg/mL, respectively. Thus, the present report put forward a novel method for the estimation of EAB, an emerging insect repellent, by using RP-HPLC technique. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Inorganic–organic hybrid materials through post-synthesis modification: Impact of the treatment with azides on the mesopore structure

PubMed Central

Keppeler, Miriam; Holzbock, Jürgen; Akbarzadeh, Johanna; Peterlik, Herwig

2011-01-01

Summary Hybrid, hierarchically organized, monolithic silica gels, comprising periodically arranged mesopores and a cellular macroscopic network, have been prepared through a co-condensation reaction of tetrakis(2-hydroxyethyl)orthosilicate with chloromethyl-trimethoxysilane or 3-(chloropropyl)-triethoxysilane. Subsequent conversion of the chloro groups into azido groups, by nucleophilic substitution with NaN3 in N,N-dimethylformamide, was conducted upon preservation of the monolithic structure. However, treatment with NaN3 had a strong influence on the structure in the mesoporous regime, with changes such as an increase of mesopore diameter, pore volume and lattice constants, as well as a concomitant decrease of the pore wall thickness, as confirmed by small angle X-ray scattering, transmission electron microscopy, and nitrogen sorption analysis. Similar effects were observed for unmodified silica gels by simple ageing in azide-containing media, whether a relatively small or a sterically demanding counter ion (Na+ or (H3C)4N+) was used. The structural modification did not seem to depend greatly on whether an organic aprotic solvent (N,N-dimethylformamide, 1,1,3,3-tetramethylurea, 1,3-dimethyl-2-imidazolidinone) or a protic solvent that can form hydrogen bonds, such as water, was used. PMID:22003454

Detection and Recovery of Palladium, Gold and Cobalt Metals from the Urban Mine Using Novel Sensors/Adsorbents Designated with Nanoscale Wagon-wheel-shaped Pores

PubMed Central

El-Safty, Sherif A.; Shenashen, Mohamed A.; Sakai, Masaru; Elshehy, Emad; Halada, Kohmei

2015-01-01

Developing low-cost, efficient processes for recovering and recycling palladium, gold and cobalt metals from urban mine remains a significant challenge in industrialized countries. Here, the development of optical mesosensors/adsorbents (MSAs) for efficient recognition and selective recovery of Pd(II), Au(III), and Co(II) from urban mine was achieved. A simple, general method for preparing MSAs based on using high-order mesoporous monolithic scaffolds was described. Hierarchical cubic Ia3d wagon-wheel-shaped MSAs were fabricated by anchoring chelating agents (colorants) into three-dimensional pores and micrometric particle surfaces of the mesoporous monolithic scaffolds. Findings show, for the first time, evidence of controlled optical recognition of Pd(II), Au(III), and Co(II) ions and a highly selective system for recovery of Pd(II) ions (up to ~95%) in ores and industrial wastes. Furthermore, the controlled assessment processes described herein involve evaluation of intrinsic properties (e.g., visual signal change, long-term stability, adsorption efficiency, extraordinary sensitivity, selectivity, and reusability); thus, expensive, sophisticated instruments are not required. Results show evidence that MSAs will attract worldwide attention as a promising technological means of recovering and recycling palladium, gold and cobaltmetals. PMID:26709467

High-Speed Observations of Dynamic Fracture Propagation in Solids and Their Implications in Earthquake Rupture Dynamics

NASA Astrophysics Data System (ADS)

Uenishi, Koji

2016-04-01

This contribution outlines our experimental observations of seismicity-related fast fracture (rupture) propagation in solids utilising high-speed analog and digital photography (maximum frame rate 1,000,000 frames per second) over the last two decades. Dynamic fracture may be triggered or initiated in the monolithic or layered seismic models by detonation of micro explosives, a projectile launched by a gun, laser pulses and electric discharge impulses, etc. First, we have investigated strike-slip rupture along planes of weakness in transparent photoelastic (birefringent) materials at a laboratory scale and shown (at that time) extraordinarily fast rupture propagation in a bi-material system and its possible effect on the generation of large strong motion in the limited narrow areas in the Kobe region on the occasion of the 1995 Hyogo-ken Nanbu, Japan, earthquake (Uenishi Ph.D. thesis 1997, Uenishi et al. BSSA 1999). In this series of experiments, we have also modelled shallow dip-slip earthquakes and indicated a possible origin of the asymmetric ground motion in the hanging and foot-walls. In the photoelastic photographs, we have found the unique dynamic wave interaction and generation of specific shear and interface waves numerically predicted by Uenishi and Madariaga (Eos 2005), and considered as a case study the seismic motion associated with the 2014 Nagano-ken Hokubu (Kamishiro Fault), Japan, dip-slip earthquake (Uenishi EFA 2015). Second, we have experimentally shown that even in a monolithic material, rupture speed may exceed the local shear wave speed if we employ hyperelasically behaving materials like natural rubber (balloons) (Uenishi Eos 2006, Uenishi ICF 2009, Uenishi Trans. JSME A 2012) but fracture in typical monolithic thin fluid films (e.g. soap bubbles, which may be treated as a solid material) propagates at an ordinary subsonic (sub-Rayleigh) speed (Uenishi et al. SSJ 2006). More recent investigation handling three-dimensional rupture propagation in monolithic brittle materials (e.g. ice spheres, concrete blocks in the field) has repeatedly indicated some specific (rather simple and smooth) fracture patterns even without the existence of distinct planes of weakness, which may help in understanding how the dynamic fracture propagation is controlled in three-dimensional brittle solids like Earth's crust (Uenishi et al. Con. Buld. Mat. 2010, 2014, JSME 2013).

Fundamental properties of monolithic bentonite buffer material formed by cold isostatic pressing for high-level radioactive waste repository

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

Kawakami, S.; Yamanaka, Y.; Kato, K.

1999-07-01

The methods of fabrication, handling, and emplacement of engineered barriers used in a deep geological repository for high level radioactive waste should be planned as simply as possible from the engineering and economic viewpoints. Therefore, a new concept of a monolithic buffer material around a waste package have been proposed instead of the conventional concept with the use of small blocks, which would decrease the cost for buffer material. The monolithic buffer material is composed of two parts of highly compacted bentonite, a cup type body and a cover. As the forming method of the monolithic buffer material, compaction bymore » the cold isostatic pressing process (CIP) has been employed. In this study, monolithic bentonite bodies with the diameter of about 333 mm and the height of about 455 mm (corresponding to the approx. 1/5 scale for the Japanese reference concept) were made by the CIP of bentonite powder. The dry densities: {rho}d of the bodies as a whole were measured and the small samples were cut from several locations to investigate the density distribution. The swelling pressure and hydraulic conductivity as function of the monolithic body density for CIP-formed specimens were also measured. High density ({rho}d: 1.4--2.0 Mg/m{sup 3}) and homogeneous monolithic bodies were formed by the CIP. The measured results of the swelling pressure (3--15 MPa) and hydraulic conductivity (0.5--1.4 x 10{sup {minus}13} m/s) of the specimens were almost the same as those for the uniaxial compacted bentonite in the literature. It is shown that the vacuum hoist system is an applicable handling method for emplacement of the monolithic bentonite.« less

Fast preparation of hybrid monolithic columns via photo-initiated thiol-yne polymerization for capillary liquid chromatography.

PubMed

Ma, Shujuan; Zhang, Haiyang; Li, Ya; Li, Yanan; Zhang, Na; Ou, Junjie; Ye, Mingliang; Wei, Yinmao

2018-02-23

Although several approaches have been developed to fabricate hybrid monoliths, it would still take a few hours to finish the formation of monoliths. Herein, photo-initiated thiol-yne polymerization was first adopted to in situ fabricate hybrid monoliths within the confines of UV-transparent fused-silica capillary. A silicon-containing diyne (1,3-diethynyltetramethyl-disiloxane, DYDS) was copolymerized with three multithiols, 1,6-hexanedithiol, trimethylolpropane tris(3-mercaptopropionate) and pentaerythriol tetrakis(3-mercaptopropionate), by using a binary porogenic system of diethylene glycol diethyl ether (DEGDE)/poly(ethylene glycol) (PEG200) within 10 min. Several characterizations of three hybrid monoliths (assigned as I, II and III, respectively) were performed. The results showed that these hybrid monoliths possessed bicontinuous porous structure, which was remarkably different from that via typical free-radical polymerization. The highest column efficiency of 76,000 plates per meter for butylbenzene was obtained on the column I in reversed-phase liquid chromatography (RPLC). It was observed that the efficiencies for strong-retained butylbenzene were almost close to those of weak-retained benzene, indicating a retention-independent efficient performance of small molecules on hybrid column I. The surface area of this hybrid monolith was very small in the dry state (less than 10.0 m 2 /g), and the chromatographic behavior of hybrid monolithic columns would be possibly explained by radical-mediated step-growth process of thiol-yne polymerization. Finally, the column I was applied for separation of BSA tryptic digest by cLC-MS/MS, indicating satisfactory separation ability for complicated samples. Copyright © 2018 Elsevier B.V. All rights reserved.

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

Serne, R. Jeffrey; Westsik, Joseph H.; Williams, Benjamin D.

This report describes the results from long-term laboratory leach tests performed at Pacific Northwest National Laboratory (PNNL) for Washington River Protection Solutions (WRPS) to evaluate the release of key constituents from monoliths of Cast Stone prepared with four simulated low-activity waste (LAW) liquid waste streams. Specific objectives of the Cast Stone long-term leach tests described in this report focused on four activities: 1. Extending the leaching times for selected ongoing EPA-1315 tests on monoliths made with LAW simulants beyond the conventional 63-day time period up to 609 days reported herein (with some tests continuing that will be documented later) inmore » an effort to evaluate long-term leaching properties of Cast Stone to support future performance assessment activities. 2. Starting new EPA-1315 leach tests on archived Cast Stone monoliths made with four LAW simulants using two leachants (deionized water [DIW] and simulated Hanford Integrated Disposal Facility (IDF) Site vadose zone pore water [VZP]). 3. Evaluating the impacts of varying the iodide loading (starting iodide concentrations) in one LAW simulant (7.8 M Na Hanford Tank Waste Operations Simulator (HTWOS) Average) by manufacturing new Cast Stone monoliths and repeating the EPA-1315 leach tests using DIW and the VZP leachants. 4. Evaluating the impacts of using a non-pertechnetate form of Tc that is present in some Hanford tanks. In this activity one LAW simulant (7.8 M Na HTWOS Average) was spiked with a Tc(I)-tricarbonyl gluconate species and then solidified into Cast Stone monoliths. Cured monoliths were leached using the EPA-1315 leach protocol with DIW and VZP. The leach results for the Tc-Gluconate Cast Stone monoliths were compared to Cast Stone monoliths pertechnetate.« less

Quasi-monolithic mirror suspensions in ground-based gravitational-wave detectors: an overview and look to the future

NASA Astrophysics Data System (ADS)

van Veggel, Anna-Maria A.

2018-05-01

At the commencement of a new era in astrophysics, with added information from direct detections of gravitational-wave (GW) signals, this paper is a testament to the quasi-monolithic suspensions of the test masses of the GW detectors that have enabled the opening of a new window on the universe. The quasi-monolithic suspensions are the final stages in the seismic isolation of the test masses in GW detectors, and are specifically designed to introduce as little thermal noise as possible. The history of the development of the fused-silica quasi-monolithic suspensions, which have been so essential for the first detections of GWs, is outlined and a glimpse into the status of research towards quasi-monolithic suspensions made of sapphire and silicon is given. This article is part of a discussion meeting issue `The promises of gravitational-wave astronomy'.

Quasi-monolithic mirror suspensions in ground-based gravitational-wave detectors: an overview and look to the future

PubMed Central

2018-01-01

At the commencement of a new era in astrophysics, with added information from direct detections of gravitational-wave (GW) signals, this paper is a testament to the quasi-monolithic suspensions of the test masses of the GW detectors that have enabled the opening of a new window on the universe. The quasi-monolithic suspensions are the final stages in the seismic isolation of the test masses in GW detectors, and are specifically designed to introduce as little thermal noise as possible. The history of the development of the fused-silica quasi-monolithic suspensions, which have been so essential for the first detections of GWs, is outlined and a glimpse into the status of research towards quasi-monolithic suspensions made of sapphire and silicon is given. This article is part of a discussion meeting issue ‘The promises of gravitational-wave astronomy’. PMID:29661973

Comparing monolithic and fused core HPLC columns for fast chromatographic analysis of fat-soluble vitamins.

PubMed

Kurdi, Said El; Muaileq, Dina Abu; Alhazmi, Hassan A; Bratty, Mohammed Al; Deeb, Sami El

2017-06-27

HPLC stationary phases of monolithic and fused core type can be used to achieve fast chromatographic separation as an alternative to UPLC. In this study, monolithic and fused core stationary phases are compared for fast separation of four fat-soluble vitamins. Three new methods on the first and second generation monolithic silica RP-18e columns and a fused core pentafluoro-phenyl propyl column were developed. Application of three fused core columns offered comparable separations of retinyl palmitate, DL-α-tocopheryl acetate, cholecalciferol and menadione in terms of elution speed and separation efficiency. Separation was achieved in approx. 5 min with good resolution (Rs > 5) and precision (RSD ≤ 0.6 %). Monolithic columns showed, however, a higher number of theoretical plates, better precision and lower column backpressure than the fused core column. The three developed methods were successfully applied to separate and quantitate fat-soluble vitamins in commercial products.

Preparation of a poly(styrene-co-DPHA-co-EDMA) monolith and its application for the separation of small molecules and biomacromolecules by HPLC.

PubMed

Wang, Xixi; Li, Xueying; Jiang, Xiaoya; Dong, Peipei; Liu, Haiyan; Bai, Ligai; Yan, Hongyuan

2017-04-01

A high performance liquid chromatography (HPLC) monolithic column was prepared by redox polymerization of styrene, dipentaerythritol hexaacrylate (DPHA) and ethylene glycol dimethacrylate (EDMA) in a porogen system of n-propanol/PEG400. The monolith was characterized by scanning electron microscopy (SEM), mercury intrusion porosimetry (MIP) and the results indicated that the monolith had a stable and homogeneous structure. The porosity of the monolithic column was 75.86% and average pore diameter was 2.1µm. Several alkylbenzenes and anilines were used to evaluate the column performance in terms of hydrophobicity. Then the column was applied to separate small molecules including phytosterol and BSA tryptic digest. Finally, five standard proteins, egg white and plasma were separated respectively and high separation capacity of protein was obtained. Copyright © 2016 Elsevier B.V. All rights reserved.

Synthesis of a specific monolithic column with artificial recognition sites for L-glutamic acid via cryo-crosslinking of imprinted nanoparticles.

PubMed

Göktürk, Ilgım; Üzek, Recep; Uzun, Lokman; Denizli, Adil

2016-06-01

In this study, a new molecular imprinting (MIP)-based monolithic cryogel column was prepared using chemically crosslinked molecularly imprinted nanoparticles, to achieve a simplified chromatographic separation (SPE) for a model compound, L-glutamic acid (L-Glu). Cryogelation through crosslinking of imprinted nanoparticles forms stable monolithic cryogel columns. This technique reduces the leakage of nanoparticles and increases the surface area, while protecting the structural features of the cryogel for stable and efficient recognition of the template molecule. A non-imprinted monolithic cryogel column (NIP) was also prepared, using non-imprinted nanoparticles produced without the addition of L-Glu during polymerization. The molecularly imprinted monolithic cryogel column (MIP) indicates apparent recognition selectivity and a good adsorption capacity compared to the NIP. Also, we have achieved a significant increase in the adsorption capacity, using the advantage of high surface area of the nanoparticles.

Monolith-based immobilized metal affinity chromatography increases production efficiency for plasmid DNA purification.

PubMed

Shin, Min Jae; Tan, Lihan; Jeong, Min Ho; Kim, Ji-Heung; Choe, Woo-Seok

2011-08-05

Immobilized metal affinity monolith column as a new class of chromatographic support is shown to be superior to conventional particle-based column as plasmid DNA (pDNA) purification platform. By harnessing the affinity of endotoxin to copper ions in the solution, a majority of endotoxin (90%) was removed from the alkaline cell lysate using CuCl(2)-induced precipitation. RNA and remaining endotoxin were subsequently removed to below detection limit with minimal loss of pDNA using either monolith or particle-based column. Monolith column has the additional advantage of feed concentration and flowrate-independent dynamic binding capacity for RNA molecules, enabling purification process to be conducted at high feed RNA concentration and flowrate. The use of monolith column gives three fold increased productivity of pDNA as compared to particle-based column, providing a more rapid and economical platform for pDNA purification. Copyright © 2011 Elsevier B.V. All rights reserved.

Quasi-monolithic mirror suspensions in ground-based gravitational-wave detectors: an overview and look to the future.

PubMed

van Veggel, Anna-Maria A

2018-05-28

At the commencement of a new era in astrophysics, with added information from direct detections of gravitational-wave (GW) signals, this paper is a testament to the quasi-monolithic suspensions of the test masses of the GW detectors that have enabled the opening of a new window on the universe. The quasi-monolithic suspensions are the final stages in the seismic isolation of the test masses in GW detectors, and are specifically designed to introduce as little thermal noise as possible. The history of the development of the fused-silica quasi-monolithic suspensions, which have been so essential for the first detections of GWs, is outlined and a glimpse into the status of research towards quasi-monolithic suspensions made of sapphire and silicon is given.This article is part of a discussion meeting issue 'The promises of gravitational-wave astronomy'. © 2018 The Authors.

Coupled Socio-Environmental Changes Triggered Indigenous Aymara Depopulation of the Semiarid Andes of Tarapacá-Chile during the Late 19th-20th Centuries.

PubMed

Lima, Mauricio; Christie, Duncan A; Santoro, M Calogero; Latorre, Claudio

2016-01-01

Socio-economic and environmental changes are well known causes of demographic collapse of agrarian cultures. The collapse of human societies is a complex phenomenon where historical and cultural dimensions play a key role, and they may interact with the environmental context. However, the importance of the interaction between socio-economic and climatic factors in explaining possible breakdowns in Native American societies has been poorly explored. The aim of this study is to test the role of socio-economic causes and rainfall variability in the collapse suffered by the Aymara people of the semiarid Andean region of Tarapacá during the period 1820-1970. Our motivation is to demonstrate that simple population dynamic models can be helpful in understanding the causes and relative importance of population changes in Andean agro-pastoral societies in responses to socio-environmental variability. Simple logistic models that combine the effects of external socio-economic causes and past rainfall variability (inferred from Gross Domestic Product [GDP] and tree-rings, respectively) were quite accurate in predicting the sustained population decline of the Aymara people. Our results suggest that the depopulation in the semiarid Tarapacá province was caused by the interaction among external socio-economic pressures given by the economic growth of the lowlands and demands for labor coupled with a persistent decline in rainfall. This study constitutes an example of how applied ecological knowledge, in particular the application of the logistic equation and theories pertaining to nonlinear population dynamics and exogenous perturbations, can be used to better understand major demographic changes in human societies.

Coupled Socio-Environmental Changes Triggered Indigenous Aymara Depopulation of the Semiarid Andes of Tarapacá-Chile during the Late 19th-20th Centuries

PubMed Central

Lima, Mauricio; Christie, Duncan A.; Santoro, M. Calogero; Latorre, Claudio

2016-01-01

Socio-economic and environmental changes are well known causes of demographic collapse of agrarian cultures. The collapse of human societies is a complex phenomenon where historical and cultural dimensions play a key role, and they may interact with the environmental context. However, the importance of the interaction between socio-economic and climatic factors in explaining possible breakdowns in Native American societies has been poorly explored. The aim of this study is to test the role of socio-economic causes and rainfall variability in the collapse suffered by the Aymara people of the semiarid Andean region of Tarapacá during the period 1820–1970. Our motivation is to demonstrate that simple population dynamic models can be helpful in understanding the causes and relative importance of population changes in Andean agro-pastoral societies in responses to socio-environmental variability. Simple logistic models that combine the effects of external socio-economic causes and past rainfall variability (inferred from Gross Domestic Product [GDP] and tree-rings, respectively) were quite accurate in predicting the sustained population decline of the Aymara people. Our results suggest that the depopulation in the semiarid Tarapacá province was caused by the interaction among external socio-economic pressures given by the economic growth of the lowlands and demands for labor coupled with a persistent decline in rainfall. This study constitutes an example of how applied ecological knowledge, in particular the application of the logistic equation and theories pertaining to nonlinear population dynamics and exogenous perturbations, can be used to better understand major demographic changes in human societies. PMID:27560499

A multispectral view of the periodic events in η Carinae†‡§¶

NASA Astrophysics Data System (ADS)

Damineli, A.; Hillier, D. J.; Corcoran, M. F.; Stahl, O.; Groh, J. H.; Arias, J.; Teodoro, M.; Morrell, N.; Gamen, R.; Gonzalez, F.; Leister, N. V.; Levato, H.; Levenhagen, R. S.; Grosso, M.; Colombo, J. F. Albacete; Wallerstein, G.

2008-06-01

A full description of the 5.5-yr low excitation events in η Carinae is presented. We show that they are not as simple and brief as previously thought, but a combination of two components. The first, the slow variation component, is revealed by slow changes in the ionization level of circumstellar matter across the whole cycle and is caused by gradual changes in the wind-wind collision shock-cone orientation, angular opening and gaseous content. The second, the collapse component, is restricted to around the minimum, and is due to a temporary global collapse of the wind-wind collision shock. High-energy photons (E > 16 eV) from the companion star are strongly shielded, leaving the Weigelt objects at low-ionization state for more than six months. High-energy phenomena are sensitive only to the collapse, low energy only to the slow variation and intermediate energies to both components. Simple eclipses and mechanisms effective only near periastron (e.g. shell ejection or accretion on to the secondary star) cannot account for the whole 5.5-yr cycle. We find anti-correlated changes in the intensity and the radial velocity of P Cygni absorption profiles in FeII λ6455 and HeI λ7065 lines, indicating that the former is associated to the primary and the latter to the secondary star. We present a set of light curves representative of the whole spectrum, useful for monitoring the next event (2009 January 11). Based partially on data collected at the OPD-LNA/MCT. Based partially on data collected at ESO telescopes. ‡ Based partially on data collected at Casleo Observatory. § Based partially on data collected at Magellan Telescopes. ¶ Based partially on data collected at CTIO. ∥ E-mail: damineli@astro.iag.usp.br

Fine-grain concrete from mining waste for monolithic construction

NASA Astrophysics Data System (ADS)

Lesovik, R. V.; Ageeva, M. S.; Lesovik, G. A.; Sopin, D. M.; Kazlitina, O. V.; Mitrokhin, A. A.

2018-03-01

The technology of a monolithic construction is a well-established practice among most Russian real estate developers. The strong points of the technology are low cost of materials and lower demand for qualified workers. The monolithic construction uses various types of reinforced slabs and foamed concrete, since they are easy to use and highly durable; they also need practically no additional treatment.

Rapid process for producing transparent, monolithic porous glass

DOEpatents

Coronado, Paul R [Livermore, CA

2006-02-14

A process for making transparent porous glass monoliths from gels. The glass is produced much faster and in much larger sizes than present technology for making porous glass. The process reduces the cost of making large porous glass monoliths because: 1) the process does not require solvent exchange nor additives to the gel to increase the drying rates, 2) only moderate temperatures and pressures are used so relatively inexpensive equipment is needed, an 3) net-shape glass monoliths are possible using this process. The process depends on the use of temperature to control the partial pressure of the gel solvent in a closed vessel, resulting in controlled shrinking during drying.

Method for making devices having intermetallic structures and intermetallic devices made thereby

DOEpatents

Paul, Brian Kevin; Wilson, Richard Dean; Alman, David Eli

2004-01-06

A method and system for making a monolithic intermetallic structure are presented. The structure is made from lamina blanks which comprise multiple layers of metals which are patternable, or intermetallic lamina blanks that are patternable. Lamina blanks are patterned, stacked and registered, and processed to form a monolithic intermetallic structure. The advantages of a patterned monolithic intermetallic structure include physical characteristics such as melting temperature, thermal conductivity, and corrosion resistance. Applications are broad, and include among others, use as a microreactor, heat recycling device, and apparatus for producing superheated steam. Monolithic intermetallic structures may contain one or more catalysts within the internal features.

Failure analysis of various monolithic posterior aesthetic dental crowns using finite element method

NASA Astrophysics Data System (ADS)

Porojan, Liliana; Topală, Florin

2017-08-01

The aim of the study was to assess the effect of material stiffness and load on the biomechanical performance of the monolithic full-coverage posterior aesthetic dental crowns using finite element analysis. Three restorative materials for monolithic dental crowns were selected for the study: zirconia; lithium disilicate glass-ceramic, and resin-based composite. Stresses were calculated in the crowns for all materials and in the teeth structures, under different load values. The experiments show that dental crowns made from all this new aesthetic materials processed by CAD/CAM technologies would be indicated as monolithic dental crowns for posterior areas.

Development of a γ-alumina- nanoparticle-functionalized porous polymer monolith for the enrichment of Sudan dyes in red wine samples.

PubMed

Li, Wanjun; Zhou, Xiao; Ye, Juanjuan; Jia, Qiong

2013-10-01

Monolithic materials were synthesized in capillaries by in situ polymerization with N-isopropylacrylamide, glycidyl methacrylate, and ethylene dimethacrylate as the monomers, and methanol and PEG as the porogens. With γ-alumina nanoparticles attached to the surface of the porous monolithic column via epoxide groups, a novel polymer monolith microextraction (PMME) material was prepared with a good mechanical stability and a high extraction capacity. SEM and X-ray photoelectron spectroscopy were employed to characterize the modified monolithic column, demonstrating that γ-alumina nanoparticles were effectively functionalized onto the monolithic column. In addition, a new method was developed for the analysis of Sudan I-IV dyes using PMME coupled with HPLC. In order to obtain the optimum extraction efficiency, the PMME conditions including desorption solvent type, sample pH, sample volume, sample flow rate, and eluent flow rate were investigated. Under the optimum conditions, we obtained acceptable linearities, low LODs, and good intra- and interday RDSs. When applied to the determination of Sudan I-IV dyes in red wine samples, satisfactory recoveries were obtained in the range of 84.0-115.9%. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Affinity monolith chromatography: A review of principles and recent analytical applications

PubMed Central

Pfaunmiller, Erika L.; Paulemond, Marie Laura; Dupper, Courtney M.; Hage, David S.

2012-01-01

Affinity monolith chromatography (AMC) is a type of liquid chromatography that uses a monolithic support and a biologically-related binding agent as a stationary phase. AMC is a powerful method for the selective separation, analysis or studies of specific target compounds in a sample. This review discusses the basic principles of AMC and recent developments or applications of this method, with particular emphasis being given to work that has appeared in the last five years. Various materials that have been used to prepare columns for AMC are examined, including organic monoliths, silica monoliths, agarose monoliths and cryogels. These supports have been used in AMC for formats that have ranged from traditional columns to disks, microcolumns and capillaries. Many binding agents have also been employed in AMC, such as antibodies, enzymes, proteins, lectins, immobilized metal-ions and dyes. Some applications that have been reported with these binding agents in AMC are bioaffinity chromatography, immunoaffinity chromatography or immunoextraction, immobilized metal-ion affinity chromatography, dye-ligand affinity chromatography, chiral separations and biointeraction studies. Examples are presented from fields that include analytical chemistry, pharmaceutical analysis, clinical testing and biotechnology. Current trends and possible future directions in AMC are also discussed. PMID:23187827

Preparation of quaternary amine monolithic column for strong anion-exchange chromatography and its application to the separation of Enterovirus 71.

PubMed

Gu, Huimin; Yin, Dezhong; Ren, Jie; Zhang, Baoliang; Zhang, Qiuyu

2016-10-15

Large size virion is unable to diffuse into pores of conventional porous chromatography particles. Therefore, separation of virion by conventional column-packing materials is not quite efficient. To solve this problem, a monolithic column with large convective pores and quaternary amine groups was prepared and was applied to separate Enterovirus 71 (EV71, ≈5700-6000kDa). Cross-section, pore structure, hydrodynamic performance, adsorption property and dynamic binding capacity of prepared monolithic column were determined. Double-pore structures, macropore at 2472nm and mesopore at 5-60nm, were formed. The porosity was up to 63.3%, which enable higher permeability and lower back pressure of the monolithic column than commercial UNO™ Q1 column. Based on the breakthrough curves, the loading capacity of bovine serum albumin was calculated to be 42.0mg per column. In addition, prepared quaternary amine monolithic column was proved to be suitable for the separation of protein mixture by strong anion-exchange chromatography. As a practical application, prepared monolith column presents excellent performance to the separation of EV71 from virus-proteins mixture. Copyright © 2016 Elsevier B.V. All rights reserved.

Edge chipping and flexural resistance of monolithic ceramics☆

PubMed Central

Zhang, Yu; Lee, James J.-W.; Srikanth, Ramanathan; Lawn, Brian R.

2014-01-01

Objective Test the hypothesis that monolithic ceramics can be developed with combined esthetics and superior fracture resistance to circumvent processing and performance drawbacks of traditional all-ceramic crowns and fixed-dental-prostheses consisting of a hard and strong core with an esthetic porcelain veneer. Specifically, to demonstrate that monolithic prostheses can be produced with a much reduced susceptibility to fracture. Methods Protocols were applied for quantifying resistance to chipping as well as resistance to flexural failure in two classes of dental ceramic, microstructurally-modified zirconias and lithium disilicate glass–ceramics. A sharp indenter was used to induce chips near the edges of flat-layer specimens, and the results compared with predictions from a critical load equation. The critical loads required to produce cementation surface failure in monolithic specimens bonded to dentin were computed from established flexural strength relations and the predictions validated with experimental data. Results Monolithic zirconias have superior chipping and flexural fracture resistance relative to their veneered counterparts. While they have superior esthetics, glass–ceramics exhibit lower strength but higher chip fracture resistance relative to porcelain-veneered zirconias. Significance The study suggests a promising future for new and improved monolithic ceramic restorations, with combined durability and acceptable esthetics. PMID:24139756

Preparation of activated carbon monolith by application of phenolic resins as carbon precursors

NASA Astrophysics Data System (ADS)

Sajad, Mehran; Kazemzad, Mahmood; Hosseinnia, Azarmidokht

2014-04-01

In the current work, activated carbon monoliths have been prepared by application of different phenolic hydrocarbons namely catechol and resorcinol as carbon precursors. For synthesis of carbon monolith, the precursors have been mixed with Genapol PF-10 as template and then polymerized in the presence of lysine as catalyst. Then the polymerized monolith carbonized in inert atmosphere at 700°C and activated by water steam at 550°C. It was found that resorcinol polymerization is easier than catechol and occurred at 90°C while for polymerization of catechol elevated temperature of 120°C at hydrothermal condition is necessary. The prepared activated carbon samples have been characterized by various analysis methods including scanning electron microscopy (SEM), surface area measurement, and transmission electron microscopy (TEM). The adsorptions of three different aromatic hydrocarbons by the prepared activated carbon samples have also been investigated by high performance liquid chromatography (HPLC) and UV-Vis spectroscopy. It was found that carbon monolith prepared by catechol as carbon precursor has higher adsorpability and strength in comparison with the other sample. The higher performance of carbon monolith prepared by catechol can be associated with its higher active sites in comparison with resorcinol.

Spacecraft Navigation Using X-ray Pulsars

DTIC Science & Technology

2006-01-01

95FEATURED RESEARCH 2006 NRL REVIEW Spacecraft Navigation Using X-ray Pulsars P.S. Ray, K.S. Wood, and B.F. Phlips E.O. Hulburt Center for Space...satellites and computes the range (technically pseudorange) to each satellite Pulsars are the collapsed remnants of massive stars that have become...relatively simple structure, pulsars are exceptionally stable rotators whose timing stability rivals that of conventional atomic clocks. A navigation

A hybrid monolithic column based on boronate-functionalized graphene oxide nanosheets for online specific enrichment of glycoproteins.

PubMed

Zhou, Chanyuan; Chen, Xiaoman; Du, Zhuo; Li, Gongke; Xiao, Xiaohua; Cai, Zongwei

2017-05-19

A hybrid monolithic column based on aminophenylboronic acid (APBA)-functionalized graphene oxide (GO) has been developed and used for selective enrichment of glycoproteins. The APBA/GO composites were homogeneously incorporated into a polymer monolithic column with the help of oligomer matrix and followed by in situ polymerization. The effect of dispersion of APBA/GO composites in the polymerization mixture on the performance of the monolithic column was explored in detail. The presence of graphene oxide not only enlarged the BET surface area from 6.3m 2 /g to 169.4m 2 /g, but also provided abundant boronic acid moieties for glycoprotein extraction, which improved the enrichment selectivity and efficiency for glycoproteins. The APBA/GO hybrid monolithic column was incorporated into a sequential injection system, which facilitated online extraction of proteins. Combining the superior properties of extraordinary surface area of GO and the affinity interaction of APBA to glycoproteins, the APBA/GO hybrid monolithic column showed higher enrichment factors for glycoproteins than other proteins without cis-diol-containing groups. Also, under comparable or even shorter processing time and without the addition of any organic solvent, it showed higher binding capacity toward glycoproteins compared with the conventional boronate affinity monolithic column. The practical applicability of this system was demonstrated by processing of egg white samples for extraction of ovalbumin and ovotransferrin, and satisfactory results were obtained by assay with SDS-PAGE. Copyright © 2017 Elsevier B.V. All rights reserved.

Dual jaw treatment of edentulism using implant-supported monolithic zirconia fixed prostheses.

PubMed

Altarawneh, Sandra; Limmer, Bryan; Reside, Glenn J; Cooper, Lyndon

2015-01-01

This case report describes restoration of the edentulous maxilla and mandible with implant supported fixed prostheses using monolithic zirconia, where the incisal edges and occluding surfaces were made of monolithic zirconia. Edentulism is a debilitating condition that can be treated with either a removable or fixed dental prosthesis. The most common type of implant-supported fixed prosthesis is the metal acrylic (hybrid), with ceramo-metal prostheses being used less commonly in complete edentulism. However, both of these prostheses designs are associated with reported complications of screw loosening or fracture and chipping of acrylic resin and porcelain. Monolithic zirconia implant-supported fixed prostheses have the potential for reduction of such complications. In this case, the CAD/CAM concept was utilized in fabrication of maxillary and mandibular screw-retained implant-supported fixed prostheses using monolithic zirconia. Proper treatment planning and execution coupled with utilizing advanced technologies contributes to highly esthetic results. However, long-term studies are required to guarantee a satisfactory long-term outcome of this modality of treatment. This case report describes the clinical and technical procedures involved in fabrication of maxillary and mandibular implant-supported fixed prostheses using monolithic zirconia as a treatment of edentulism, and proposes the possible advantages associated with using monolithic zirconia in eliminating dissimilar interfaces in such prostheses that are accountable for the most commonly occurring technical complication for these prostheses being chipping and fracture of the veneering material. © 2015 Wiley Periodicals, Inc.

Ultrafast preparation of a polyhedral oligomeric silsesquioxane-based ionic liquid hybrid monolith via photoinitiated polymerization, and its application to capillary electrochromatography of aromatic compounds.

PubMed

Zhang, Bingyu; Lei, Xiaoyun; Deng, Lijun; Li, Minsheng; Yao, Sicong; Wu, Xiaoping

2018-06-06

An ionic liquid hybrid monolithic capillary column was prepared within 7 min via photoinitiated free-radical polymerization of an ionic liquid monomer (1-butyl-3-vinylimidazolium-bis[(trifluoromethyl)sulfonyl]imide); VBIMNTF 2 ) and a methacryl substituted polyhedral oligomeric silsesquioxane (POSS-MA) acting as a cross-linker. The effects of composition of prepolymerization solution and initiation time on the porous structure and electroosmotic flow (EOF) of monolithic column were investigated. The hybrid monolith was characterized by scanning electron microscopy and FTIR. Owing to the introduction of a rigid nanosized POSS silica core and ionic liquids with multiple interaction sites, the monolithic column has a well-defined 3D skeleton morphology, good mechanical stability, and a stable anodic electroosmotic flow. The hybrid monolithic stationary phase was applied to the capillary electrochromatographic separation of various alkylbenzenes, phenols, anilines and polycyclic aromatic hydrocarbons (PAHs). The column efficiency is highest (98,000 plates/m) in case of alkylbenzenes. Mixed-mode retention mechanisms including hydrophobic interactions, π-π stacking, electrostatic interaction and electrophoretic mobility can be observed. This indicates the potential of this material in terms of efficient separation of analytes of different structural type. Graphical Abstract Preparation of a mixed-mode ionic liquid hybrid monolithic column via photoinitiated polymerization of methacryl substituted polyhedral oligomeric silsesquioxane (POSS-MA) and 1-butyl-3-vinylimidazolium-bis[(trifluoromethyl)sulfonyl]imide (VBIMNTF 2 ) ionic liquid for use in capillary electrochromatography.

Graphene oxide-based composite monolith as new sorbent for the on-line solid phase extraction and high performance liquid chromatography determination of ß-sitosterol in food samples.

PubMed

Cui, Beijiao; Guo, Bin; Wang, Huimin; Zhang, Doudou; Liu, Haiyan; Bai, Ligai; Yan, Hongyuan; Han, Dandan

2018-08-15

A composite monolithic column was prepared by redox initiation method for the on-line purification and enrichment of β-sitosterol, in which graphene oxide (GO) was embedded. The obtained monolithic column was characterized by scanning electron microscopy (SEM) and nitrogen adsorption-desorption isotherm measurement, which indicated that the monolith possessed characteristics of porous structure and high permeability. Under the optimum conditions for extraction and determination, the calibration equation was y = 47.92 × -0.1391; the linear range was 0.008-1.0 mg mL -1 ; the linear regression coefficient was 0.998; the limit of detection (LOD) is 2.4 μg mL -1 ; the limit of quantitation (LOQ) was 8 μg mL -1 ; precisions for intra-day and inter-day assays presented as relative standard deviations were less than 4.3% and 6.8%, respectively. Under the selective conditions, the enrichment factor of the method was 119. The recovery was in the range of 80.40-98.00%. Moreover, the adsorption amount of the monolith was compared with silica gel-C18 adsorbent and the monolith without graphene oxide being embedded. The polymerization monolithic column showed high selectivity and good permeability, and it was successfully used as on-line solid-phase extraction (SPE) column for determination of β-sitosterol in edible oil. Copyright © 2018 Elsevier B.V. All rights reserved.

Anomalous critical behavior in the polymer collapse transition of three-dimensional lattice trails.

PubMed

Bedini, Andrea; Owczarek, Aleksander L; Prellberg, Thomas

2012-07-01

Trails (bond-avoiding walks) provide an alternative lattice model of polymers to self-avoiding walks, and adding self-interaction at multiply visited sites gives a model of polymer collapse. Recently a two-dimensional model (triangular lattice) where doubly and triply visited sites are given different weights was shown to display a rich phase diagram with first- and second-order collapse separated by a multicritical point. A kinetic growth process of trails (KGTs) was conjectured to map precisely to this multicritical point. Two types of low-temperature phases, a globule phase and a maximally dense phase, were encountered. Here we investigate the collapse properties of a similar extended model of interacting lattice trails on the simple cubic lattice with separate weights for doubly and triply visited sites. Again we find first- and second-order collapse transitions dependent on the relative sizes of the doubly and triply visited energies. However, we find no evidence of a low-temperature maximally dense phase with only the globular phase in existence. Intriguingly, when the ratio of the energies is precisely that which separates the first-order from the second-order regions anomalous finite-size scaling appears. At the finite-size location of the rounded transition clear evidence exists for a first-order transition that persists in the thermodynamic limit. This location moves as the length increases, with its limit apparently at the point that maps to a KGT. However, if one fixes the temperature to sit at exactly this KGT point, then only a critical point can be deduced from the data. The resolution of this apparent contradiction lies in the breaking of crossover scaling and the difference in the shift and transition width (crossover) exponents.

Translucency and Strength of High-Translucency Monolithic Zirconium-Oxide Materials

DTIC Science & Technology

2016-05-12

APPROV~, Col Drew W. Fallis Dean, Air Force Postgraduate Dental School r UNIFORMED SERVICES UNIVERSITY OF THE HEALTH SCIENCES AIR FORCE...POSTGRADUATE DENTAL SCHOOL 2450 Pepperrell Street Lackland AFB Texas, 78236-5345 http://www.usuhs.mil "The author hereby certifies that the use of any...Translucency Monolithic Zirconium-Oxide Materials Abstract Dental materials manufacturers have developed more translucent monolithic zirconium oxide

Monolithic microcircuit techniques and processes

NASA Technical Reports Server (NTRS)

Kennedy, B. W.

1972-01-01

Brief discussions of the techniques used to make dielectric and metal thin film depositions for monolithic circuits are presented. Silicon nitride deposition and the properties of silicon nitride films are discussed. Deposition of dichlorosilane and thermally grown silicon dioxide are reported. The deposition and thermal densification of borosilicate, aluminosilicate, and phosphosilicate glasses are discussed. Metallization for monolithic circuits and the characteristics of thin films are also included.

Monolithic thermally bonded Er3+, Yb3+:glass/Co2+:MgAl2O4 microchip lasers

NASA Astrophysics Data System (ADS)

Mlynczak, Jaroslaw; Belghachem, Nabil

2015-12-01

The highest ever reported 10 kW peak power in monolithic thermally bonded Er3+, Yb3+:glass/Co2+:MgAl2O4 microchip laser was achieved. To show the superiority of monolithic microchip lasers over those with external mirrors the laser generation characteristics of the same samples in both cases were compared.

Highly versatile in-reflection photonic crystal fibre interferometer

NASA Astrophysics Data System (ADS)

Jha, Rajan; Villatoro, Joel; Kreuzer, Mark; Finazzi, Vittoria; Pruneri, Valerio

2009-10-01

We report a simple and highly versatile photonic crystal fiber (PCF) interferometer that operates in reflection mode. The device consists of a short section of PCF fusion spliced at the distal end of a standard single mode fiber. The air-holes of the PCF are intentionally collapsed over a microscopic region around the splice. The collapsed region broadens the propagating mode because of diffraction. This allows the coupling and recombination of two PCF modes. Depending on the PCF structure two core modes or a core and a cladding mode can be excited. In either case the devices exhibit sinusoidal interference patterns with fringe spacing depending on the PCF length. The interferometers are highly stable over time and can operate at high temperatures with minimal degradation. The interferometers are suitable for highresolution sensing of strain, refractive index (biosensing), gases, volatile organic compounds, etc.

Method of making improved gas storage carbon with enhanced thermal conductivity

DOEpatents

Burchell, Timothy D [Oak Ridge, TN; Rogers, Michael R [Knoxville, TN

2002-11-05

A method of making an adsorbent carbon fiber based monolith having improved methane gas storage capabilities is disclosed. Additionally, the monolithic nature of the storage carbon allows it to exhibit greater thermal conductivity than conventional granular activated carbon or powdered activated carbon storage beds. The storage of methane gas is achieved through the process of physical adsorption in the micropores that are developed in the structure of the adsorbent monolith. The disclosed monolith is capable of storing greater than 150 V/V of methane [i.e., >150 STP (101.325 KPa, 298K) volumes of methane per unit volume of storage vessel internal volume] at a pressure of 3.5 MPa (500 psi).

Design considerations for a monolithic, GaAs, dual-mode, QPSK/QASK, high-throughput rate transceiver. M.S. Thesis

NASA Technical Reports Server (NTRS)

Kot, R. A.; Oliver, J. D.; Wilson, S. G.

1984-01-01

A monolithic, GaAs, dual mode, quadrature amplitude shift keying and quadrature phase shift keying transceiver with one and two billion bits per second data rate is being considered to achieve a low power, small and ultra high speed communication system for satellite as well as terrestrial purposes. Recent GaAs integrated circuit achievements are surveyed and their constituent device types are evaluated. Design considerations, on an elemental level, of the entire modem are further included for monolithic realization with practical fabrication techniques. Numerous device types, with practical monolithic compatability, are used in the design of functional blocks with sufficient performances for realization of the transceiver.

Electrochromatography on acrylate-based monolith in cyclic olefin copolymer microchip: an attractive technology.

PubMed

Ladner, Y; Cretier, G; Faure, K

2015-01-01

Electrochromatography (EC) on a porous monolithic stationary phase prepared within the channels of a microsystem is an attractive alternative for on-chip separation. It combines the separation mechanisms of electrophoresis and liquid chromatography. Moreover, the porous polymer monolithic materials have become popular as stationary phase due to the ease and rapidity of fabrication via free radical photopolymerization. Here, we describe a hexyl acrylate (HA)-based porous monolith which is simultaneously in situ synthesized and anchored to the inner walls of the channel of a cyclic olefin copolymer (COC) device in only 2 min. The baseline separation of a mixture of neurotransmitters including six amino acids and two catecholamines is realized.

Waveguide based compact silicon Schottky photodetector with enhanced responsivity in the telecom spectral band.

PubMed

Goykhman, Ilya; Desiatov, Boris; Khurgin, Jacob; Shappir, Joseph; Levy, Uriel

2012-12-17

We experimentally demonstrate an on-chip compact and simple to fabricate silicon Schottky photodetector for telecom wavelengths operating on the basis of internal photoemission process. The device is realized using CMOS compatible approach of local-oxidation of silicon, which enables the realization of the photodetector and low-loss bus photonic waveguide at the same fabrication step. The photodetector demonstrates enhanced internal responsivity of 12.5mA/W for operation wavelength of 1.55µm corresponding to an internal quantum efficiency of 1%, about two orders of magnitude higher than our previously demonstrated results [22]. We attribute this improved detection efficiency to the presence of surface roughness at the boundary between the materials forming the Schottky contact. The combination of enhanced quantum efficiency together with a simple fabrication process provides a promising platform for the realization of all silicon photodetectors and their integration with other nanophotonic and nanoplasmonic structures towards the construction of monolithic silicon opto-electronic circuitry on-chip.

TABLET: The personal computer of the year 2000

NASA Technical Reports Server (NTRS)

Mel, Bartlett W.; Omohundro, Stephen M.; Robison, Arch D.; Skiena, Steven S.; Thearling, Kurt H.; Young, Luke T.; Wolfram, Stephen

1988-01-01

The University of Illinois design of the TABLET portable computer extends the freedom of pen and notepad with a machine that draws on the projected power of 21st century technology. Without assuming any new, major technological breakthroughs, it seeks to balance the promises of today's growing technologies with the changing role of computers in tomorrow's education, research, security, and commerce. It seeks to gather together in one basket the matured fruits of such buzzword technologies as LCD, GPS, CCD, WSI, and DSP. The design is simple, yet sleek. Roughly the size and weight of a notebook, the machine is a dark, featureless monolith with no moving parts. Through magneto-optics, a simple LaserCard provides exchangeable, mass data storage. Its I/O surface, in concert with built-in infrared and cellular transceivers, puts the user in touch with anyone and anything. The ensemble of these components, directed by software that can transform it into anything from a keyboard or notepad to an office or video studio, suggests an instrument of tremendous power and freedom.

Miniaturized monolithic columns for the electrochromatographic separation and SERS detection of molecules of exobiological interest

NASA Astrophysics Data System (ADS)

Carbonnier, Benjamin; Guerrouache, Mohamed

Development of miniaturized separation and detection media represents one of the major challenges in the field of modern analytical chemistry dedicated to space exploration. To date, gas chromatography-mass spectrometry has been selected as the method of choice for exobiology flight experiments for seeking for organic molecules and especially potential chemical indicators of life. [1] Liquid phase separation methods have also been developed with for instance, the so-called Mars Organic Analyzer (MOA) capillary electrophoresis (CE) microchip.[2] Although CE offers the advantages of easy miniaturization and high separation efficiency it suffers from a lack of selectivity towards a broad range of analytes with varied chemical nature. In this respect, we propose the use of capillary columns filled with monolithic stationary phases for the electrochromatographic separation of organic molecules of exobiology interest. Polymer monoliths have attracted a great deal of interest in analytical science over the last years as (electro)chromatographic stationary phases [3], immunosensors [4]. Beyond the intrinsic properties of monolithic polymers, i.e. fast mass transport between the monolithic support and the surrounding fluid and high permeability, other major advantages are their easy in situ preparation and tuning of surface functionality. Indeed, monoliths can be simply prepared through free radical copolymerization of a homogeneous mixture made of monomers, cross-linkers, porogenic solvents and initiator. UV-initiation process has been exploited to the synthesis of a discrete section of monolith as a flow-through active element within the confines of micro channels [5,6] while two-step strategies have been reported for the design of varied adsorbent starting with a generic monolith [7,8]. Although a nearly limitless range of monolithic supports can be prepared by this traditional method, the resulting monoliths exhibit unique function. In this contribution, we describe an elegant strategy for preparing multifunctional monoliths through spatially controlled surface functionalization.[9] Photochemical initiation affords spatial control over the reaction site, i.e. site-specific immobilization of ligands on the pore surface of the monolith. Hydrophobic and hydrophilic molecular entities were successfully grafted and the obtained monoliths were applied to electrochromatographic separation application under reversed-phase and hydrophilic interaction electrochromatography modes, respectively. The panel of successfully analyzed analytes ranges from hydrophobic polycyclic aromatic hydrocarbons to life markers such as amino acids and peptides. Our approach was extended to the local design of chelating interface for the site-specific immobilisation of gold nanoparticles. Taking advantage of the unique properties of supported nano-gold, it was possible to perform surface enhanced Raman spectroscopy (SERS) sensing of organic molecules at the sub-nanomolar level. This work is funded by the French Space Agency (CNES) References [1] M.C. Pietrogrande, M.G. Zampolli, F. Dondi, C. Szopa, R. Sternberg, A. Buch, J.F. Raulin, J. Chromatogr. A 1071 (2005) 255. [2] A. M. Stockton, T.M. Chiesl, J.M. Scherer, R. A. Mathies, Anal. Chem. 81 (2009) 790 [3] B. Carbonnier, M. Guerrouache, R. Denoyel, M. C. Millot, J. Sep. Sci. 30 (2007) 3000. [4] J.k. Liu, C.F. Chen, C.W. Chang, D.L. DeVoe, Biosensors Bioelectron. 26 (2010) 182. [5] J. Krenkova, F. Svec, J. Sep. Sci. 32 (2009) 706. [6] F. Svec, J. Chromatogr. B 841 (2004) 52 [7] M. Guerrouache, M. C. Millot, B. Carbonnier, Macromol. Rapid. Commun, 30 (2009) 109. [8] M. Guerrouache, B. Carbonnier, C. Vidal-Madjar, M.C. Millot, J. Chromatogr A, 1149 (2007) 368. [9] M. Guerrouache, S. Mahouche Chergui, M.M. Chehimi, B. Carbonnier. Chem. Commun. 48 (2012) 7486.

Simultaneous determination of tylosin and josamycin residues in muscles, liver, eggs and milk by MLC with a monolithic column and time-programmed UV detection: application to baby food and formulae

PubMed Central

2014-01-01

Background Tylosin and Josamycin are macrolide antibiotics. They are used in the treatment of pneumonia, arthritis and mastitis in cattle, and mycoplasma infections in poultry. The incorrect use of antibiotics has lead to the presence of antibiotic residues in foods. The residues cause toxic effects on consumers. Results A simple and sensitive method was optimized and validated for the analysis of tylosin and josamycin residues in food samples. Analytical separation was performed in less than 10 min using a RP C18 monolithic column with time-programmed UV detection at 287 nm and 232 nm and a micellar solution of 0.17 M sodium dodecyl sulphate, 14% methanol and 0.3% triethylamine in 0.02 M phosphoric acid buffered at pH 4 as the mobile phase. The method was fully validated in accordance with ICH guidelines. The micellar method was successfully applied to quantitatively determine tylosin and josamycin residues in spiked chicken muscles, chicken liver, bovine muscles, liver, milk and eggs. It was also extended to the determination of tylosin and josamycin residues in chicken-based baby food and baby formulae. The compounds were separated by a monolithic column which, on account of its particular structure, could bear higher flow rates than usually found for this kind of analysis. High extraction efficiency for tylosin and josamycin was obtained without matrix interference in the extraction process and in the subsequent chromatographic determination. No organic solvent was used during the pretreatment step. Hence, it is considered an interesting technique for “green” chemistry. Conclusion The proposed method was validated and successfully applied for the determination of tylosin and josamycin residues in spiked chicken muscles, chicken liver, bovine muscles, liver, milk and eggs. It was also extended to the determination of tylosin and josamycin residues in chicken-based baby food and baby formulae. PMID:24976860

Activated, coal-based carbon foam

DOEpatents

Rogers, Darren Kenneth; Plucinski, Janusz Wladyslaw

2004-12-21

An ablation resistant, monolithic, activated, carbon foam produced by the activation of a coal-based carbon foam through the action of carbon dioxide, ozone or some similar oxidative agent that pits and/or partially oxidizes the carbon foam skeleton, thereby significantly increasing its overall surface area and concurrently increasing its filtering ability. Such activated carbon foams are suitable for application in virtually all areas where particulate or gel form activated carbon materials have been used. Such an activated carbon foam can be fabricated, i.e. sawed, machined and otherwise shaped to fit virtually any required filtering location by simple insertion and without the need for handling the "dirty" and friable particulate activated carbon foam materials of the prior art.

Influence of bending strains on radio frequency characteristics of flexible microwave switches using single-crystal silicon nanomembranes on plastic substrate

NASA Astrophysics Data System (ADS)

Qin, Guoxuan; Yuan, Hao-Chih; Celler, George K.; Ma, Jianguo; Ma, Zhenqiang

2011-10-01

This letter presents radio frequency (RF) characterization of flexible microwave switches using single-crystal silicon nanomembranes (SiNMs) on plastic substrate under various uniaxial mechanical tensile bending strains. The flexible switches shows significant/negligible performance enhancement on strains under on/off states from dc to 10 GHz. Furthermore, an RF/microwave strain equivalent circuit model is developed and reveals the most influential factors, and un-proportional device parameters change with bending strains. The study demonstrates that flexible microwave single-crystal SiNM switches, as a simple circuit example towards the goal of flexible monolithic microwave integrated circuits, can be properly operated and modeled under mechanical bending conditions.

Preparation of a zeolite-modified polymer monolith for identification of synthetic colorants in lipsticks

NASA Astrophysics Data System (ADS)

Wang, Huiqi; Li, Zheng; Niu, Qian; Ma, Jiutong; Jia, Qiong

2015-10-01

A novel zeolite-modified poly(methacrylic acid-ethylenedimethacrylate) (zeolite@poly(MAA-EDMA)) monolithic column was prepared with the in situ polymerization method and employed in polymer monolith microextraction for the separation and preconcentration of synthetic colorants combined with high performance liquid chromatography. The polymer was characterized by scanning electronmicroscopy, Fourier-transform infrared spectroscopy, X-ray photoelectron spectroscopy, and thermo-gravimetric analysis. Various parameters affecting the extraction efficiency were investigated and optimized. Under the optimum experimental conditions, we obtained acceptable linearities, low limits of detection, and good intra-day/inter-day relative standard deviations. The method was applied to the determination of synthetic colorants in lipsticks with recoveries ranged from 70.7% to 109.7%. Compared with conventional methacrylic acid-based monoliths, the developed monolith exhibited high enrichment capacity because of the introduction of zeolites into the preparation process. The extraction efficiency followed the order: zeolite@poly(MAA-EDMA) > poly(MAA-EDMA) > direct HPLC analysis.

Quasi-monolithic tunable optical resonator

NASA Technical Reports Server (NTRS)

Arbore, Mark (Inventor); Tapos, Francisc (Inventor)

2003-01-01

An optical resonator has a piezoelectric element attached to a quasi-monolithic structure. The quasi-monolithic structure defines an optical path. Mirrors attached to the structure deflect light along the optical path. The piezoelectric element controllably strains the quasi-monolithic structure to change a length of the optical path by about 1 micron. A first feedback loop coupled to the piezoelectric element provides fine control over the cavity length. The resonator may include a thermally actuated spacer attached to the cavity and a mirror attached to the spacer. The thermally actuated spacer adjusts the cavity length by up to about 20 microns. A second feedback loop coupled to the sensor and heater provides a coarse control over the cavity length. An alternative embodiment provides a quasi-monolithic optical parametric oscillator (OPO). This embodiment includes a non-linear optical element within the resonator cavity along the optical path. Such an OPO configuration is broadly tunable and capable of mode-hop free operation for periods of 24 hours or more.

Microporous spongy chitosan monoliths doped with graphene oxide as highly effective adsorbent for methyl orange and copper nitrate (Cu(NO3)2) ions.

PubMed

Wang, Ying; Liu, Xu; Wang, Hongfang; Xia, Guangmei; Huang, Wei; Song, Rui

2014-02-15

In the current study, microporous spongy chitosan monoliths doped with small amount of graphene oxide (CSGO monoliths) with high porosity (96-98%), extraordinary high water absorption (more than 2000%) and low density (0.0436-0.0607 g cm(-3)) were prepared by the freeze-drying method and used as adsorbents for anionic dyes methyl orange (MO) and Cu(2+) ions. The adsorption behavior of the CSGO monoliths and influencing factors such as pH value, graphene oxide (GO) content, concentration of pollutants as well as adsorption kinetics were studied. Specifically, the saturated adsorption capacity for MO is 567.07 mg g(-1), the highest comparing with other publication results, and it is 53.69 mg g(-1) for Cu(2+) ions. Since they are biodegradable, non-toxic, efficient, low-cost and easy to prepare, we believe that these microporous spongy CSGO monoliths will be the promising candidates for water purification. Copyright © 2013 Elsevier Inc. All rights reserved.

Monolithic methacrylate packed 96-tips for high throughput bioanalysis.

PubMed

Altun, Zeki; Skoglund, Christina; Abdel-Rehim, Mohamed

2010-04-16

In the pharmaceutical industry the growing number of samples to be analyzed requires high throughput and fully automated analytical techniques. Commonly used sample-preparation methods are solid-phase extraction (SPE), liquid-liquid extraction (LLE) and protein precipitation. In this paper we will discus a new sample-preparation technique based on SPE for high throughput drug extraction developed and used by our group. This new sample-preparation method is based on monolithic methacrylate polymer as packing sorbent for 96-tip robotic device. Using this device a 96-well plate could be handled in 2-4min. The key aspect of the monolithic phase is that monolithic material can offer both good binding capacity and low back-pressure properties compared to e.g. silica phases. The present paper presents the successful application of monolithic 96-tips and LC-MS/MS by the sample preparation of busulphan, rescovitine, metoprolol, pindolol and local anaesthetics from human plasma samples and cyklophosphamid from mice blood samples. Copyright 2009 Elsevier B.V. All rights reserved.

Affinity monolith-integrated poly(methyl methacrylate) microchips for on-line protein extraction and capillary electrophoresis.

PubMed

Sun, Xiuhua; Yang, Weichun; Pan, Tao; Woolley, Adam T

2008-07-01

Immunoaffinity monolith pretreatment columns have been coupled with capillary electrophoresis separation in poly(methyl methacrylate) (PMMA) microchips. Microdevices were designed with eight reservoirs to enable the electrically controlled transport of selected analytes and solutions to carry out integrated immunoaffinity extraction and electrophoretic separation. The PMMA microdevices were fabricated reproducibly and with high fidelity by solvent imprinting and thermal bonding methods. Monoliths with epoxy groups for antibody immobilization were prepared by direct in situ photopolymerization of glycidyl methacrylate and ethylene glycol dimethacrylate in a porogenic solvent consisting of 70% 1-dodecanol and 30% cyclohexanol. Antifluorescein isothiocyanate was utilized as a model affinity group in the monoliths, and the immobilization process was optimized. A mean elution efficiency of 92% was achieved for the monolith-based extraction of fluorescein isothiocyanate (FITC)-tagged human serum albumin. FITC-tagged proteins were purified from a contaminant protein and then separated electrophoretically using these devices. The developed immunoaffinity column/capillary electrophoresis microdevices show great promise for combining sample pretreatment and separation in biomolecular analysis.

Affinity Monolith-Integrated Poly(methyl Methacrylate) Microchips for On-Line Protein Extraction and Capillary Electrophoresis

PubMed Central

Sun, Xiuhua; Yang, Weichun; Pan, Tao; Woolley, Adam T.

2008-01-01

Immunoaffinity monolith pretreatment columns have been coupled with capillary electrophoresis separation in poly(methyl methacrylate) (PMMA) microchips. Microdevices were designed with 8 reservoirs to enable the electrically controlled transport of selected analytes and solutions to carry out integrated immunoaffinity extraction and electrophoretic separation. The PMMA microdevices were fabricated reproducibly and with high fidelity by solvent imprinting and thermal bonding methods. Monoliths with epoxy groups for antibody immobilization were prepared by direct in-situ photopolymerization of glycidyl methacrylate and ethylene dimethacrylate in a porogenic solvent consisting of 70% dodecanol and 30% hexanol. Anti-fluorescein isothiocyanate (FITC) was utilized as a model affinity group in the monoliths, and the immobilization process was optimized. A mean elution efficiency of 92% was achieved for the monolith-based extraction of FITC-tagged human serum albumin. FITC-tagged proteins were purified from a contaminant protein and then separated electrophoretically using these devices. The developed immunoaffinity column/capillary electrophoresis microdevices show great promise for combining sample pretreatment and separation in biomolecular analysis. PMID:18479142

Dopamine-imprinted monolithic column for capillary electrochromatography.

PubMed

Aşır, Süleyman; Sarı, Duygu; Derazshamshir, Ali; Yılmaz, Fatma; Şarkaya, Koray; Denizli, Adil

2017-11-01

A dopamine-imprinted monolithic column was prepared and used in capillary electrochromatography as stationary phase for the first time. Dopamine was selectively separated from aqueous solution containing the competitor molecule norepinephrine, which is similar in size and shape to the template molecule. Morphology of the dopamine-imprinted column was observed by scanning electron microscopy. The influence of the organic solvent content of mobile phase, applied pressure and pH of the mobile phase on the recognition of dopamine by the imprinted monolithic column has been evaluated, and the imprinting effect in the dopamine-imprinted monolithic polymer was verified. Developed dopamine-imprinted monolithic column resulted in excellent separation of dopamine from structurally related competitor molecule, norepinephrine. Separation was achieved in a short period of 10 min, with the electrophoretic mobility of 5.81 × 10 -5  m 2 V -1 s -1 at pH 5.0 and 500 mbar pressure. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Recommendations for Secure Initialization Routines in Operating Systems

DTIC Science & Technology

2004-12-01

monolithic design is used. This term is often used to distinguish the operating system from supporting software, e.g. “The Linux kernel does not specify...give the operating system structure and organization. Yet the overall monolithic design of the kernel still falls under Tannenbaum and Woodhull’s “Big...modules that handle initialization tasks. Any further subdivision would complicate interdependencies that are a result of having a monolithic kernel

Effect of flame retardants on the properties of monolithic and foamed polyurethanes at low temperatures

NASA Astrophysics Data System (ADS)

Yakushin, V. A.; Stirna, U. K.; Zhmud', N. P.

1999-09-01

The dependence of physical and mechanical properties of monolithic and foamed rigid polyurethanes on the content of flame retardants was investigated at 293 and 98 K. The character of the influence of the content of trichloroethyl phosphate on the ultimate tensile elongation and the coefficient of linear thermal expansion for monolithic and foamed polyurethanes at a temperature of 98 K was established.

Optoelectronic devices toward monolithic integration

NASA Astrophysics Data System (ADS)

Ghergia, V.

1992-12-01

Starting from the present state of tl art of discrete devices up to the on going realization of monolithic semicorxtuctor integrated prototypes an overview ofoptoelectronic devices for telecom applications is given inchiding a short classification of the different kind of integrated devices. On the future perspective of IBCN distribution network some economica of hybrid and monolithic forms of integration are attempted. lnaflyashoitpresentationoftheactivitiesperformedintbefieldofmonolithic integration by EEC ESPR1T and RACE projects is reported. 1.

Two stage dual gate MESFET monolithic gain control amplifier for Ka-band

NASA Technical Reports Server (NTRS)

Sokolov, V.; Geddes, J.; Contolatis, A.

1987-01-01

A monolithic two stage gain control amplifier has been developed using submicron gate length dual gate MESFETs fabricated on ion implanted material. The amplifier has a gain of 12 dB at 30 GHz with a gain control range of over 30 dB. This ion implanted monolithic IC is readily integrable with other phased array receiver functions such as low noise amplifiers and phase shifters.

Monolithic integration of multiple wavelength vertical-cavity surface-emitting lasers by mask molecular beam epitaxy

NASA Astrophysics Data System (ADS)

Saito, Hideaki; Ogura, Ichiro; Sugimoto, Yoshimasa; Kasahara, Kenichi

1995-05-01

The monolithic incorporation and performance of vertical-cavity surface-emitting lasers (VCSELs) emitting at two distinct wavelengths, which were suited for application to wavelength division multiplexing (WDM) systems were reported. The monolithic integration of two-wavelength VCSEL arrays was achieved by using mask molecular beam epitaxy. This method can generate arrays that have the desired integration area size and wavelength separation.

Pre-Big-Bang bubbles from the gravitational instability of generic string vacua

NASA Astrophysics Data System (ADS)

Buonanno, A.; Damour, T.; Veneziano, G.

1999-03-01

We formulate the basic postulate of pre-Big-Bang cosmology as one of ``asymptotic past triviality", by which we mean that the initial state is a generic perturbative solution of the tree-level low-energy effective action. Such a past-trivial ``string vacuum'' is made of an arbitrary ensemble of incoming gravitational and dilatonic waves, and is generically prone to gravitational instability, leading to the possible formation of many black holes hiding singular space-like hypersurfaces. Each such singular space-like hypersurface of gravitational collapse becomes, in the string-frame metric, the usual Big-Bang t=0 hypersurface, i.e. the place of birth of a baby Friedmann universe after a period of dilaton-driven inflation. Specializing to the spherically symmetric case, we review and reinterpret previous work on the subject, and propose a simple, scale-invariant criterion for collapse/inflation in terms of asymptotic data at past null infinity. Those data should determine whether, when, and where collapse/inflation occurs, and, when it does, fix its characteristics, including anisotropies on the Big-Bang hypersurface whose imprint could have survived till now. Using Bayesian probability concepts, we finally attempt to answer some fine-tuning objections recently moved to the pre-Big-Bang scenario.

Variation in multiring basic structures as a function of impact angle

NASA Technical Reports Server (NTRS)

Wichman, R. W.; Schultz, P. H.

1992-01-01

Previous studies have demonstrated that the impact process in the laboratory varies as a function of impact angle. This variation is attributed to changes in energy partitioning and projectile failure during the impact and, in simple craters, produces a sequence of progressively smaller and more asymmetric crater forms as impact angle decreases from approximately 20 degrees. Variations in impact angle can produce differences in the appearance of multiring impact basins. Comparisons of Orientale to the more oblique impact structure at Crisium also suggests that these differences primarily reflect the degree of cavity collapse. The relative changes in massif ring topography, basin scarp relief, and the distribution of peripheral mare units are consistent with a reduction in degree of cavity collapse with decreasing impact angle. The prominent uprange basin scarps and the restriction of tectonically derived peripheral mare units along uprange ring structures also may indicate an uprange enhancement of failure during cavity collapse. Finally, although basin ring faults appear to be preferred pathways for mare volcanism, fault-controlled peripheral mare volcanism occurs most readily uprange of an oblique impact; elsewhere such volcanism apparently requires superposition of an impact structure on the ring fault.

Catalytic oxidation of toluene: comparative study over powder and monolithic manganese-nickel mixed oxide catalysts.

PubMed

Duplančić, Marina; Tomašić, Vesna; Gomzi, Zoran

2017-07-05

This paper is focused on development of the metal monolithic structure for total oxidation of toluene at low temperature. The well-adhered catalyst, based on the mixed oxides of manganese and nickel, is washcoated on the Al/Al 2 O 3 plates as metallic support. For the comparison purposes, results observed for the manganese-nickel mixed oxide supported on the metallic monolith are compared with those obtained using powder type of the same catalyst. Prepared manganese-nickel mixed oxides in both configurations show remarkable low-temperature activity for the toluene oxidation. The reaction temperature T 50 corresponding to 50% of the toluene conversion is observed at temperatures of ca. 400-430 K for the powder catalyst and at ca. 450-490 K for the monolith configuration. The appropriate mathematical models, such as one-dimensional (1D) pseudo-homogeneous model of the fixed bed reactor and the 1D heterogeneous model of the metal monolith reactor, are applied to describe and compare catalytic performances of both reactors. Validation of the applied models is performed by comparing experimental data with theoretical predictions. The obtained results confirmed that the reaction over the monolithic structure is kinetically controlled, while in the case of the powder catalyst the reaction rate is influenced by the intraphase diffusion.

CEC with new monolithic stationary phase based on a fluorinated monomer, trifluoroethyl methacrylate.

PubMed

Yurtsever, Arda; Saraçoğlu, Berna; Tuncel, Ali

2009-02-01

A new, fluorinated monolithic stationary phase for CEC was first synthesized by a single-stage, thermally initiated copolymerization of a fluorinated monomer, 2,2,2-trifluoroethyl methacrylate (TFEM) and ethylene dimethacrylate (EDMA) in the presence of a porogen mixture. In this preparation, 2-acrylamido-2-methyl-1-propanesulfonic acid was used as the charge-bearing monomer. The porogen mixture was prepared by mixing isoamylalcohol and 1,4-butanediol. A clear increase in the electroosmotic mobility was observed with increasing pH. The electroosmotic mobility decreased with increasing ACN concentration. Poly(TFEM-co-EDMA) monolith prepared under optimized polymerization conditions was successfully used in the separation of alkylbenzenes and phenols by CEC. The best chromatographic separation for alkylbenzenes was performed with lower ACN concentrations (i.e. 60% v/v) with respect to the common acrylic-based CEC monoliths. The theoretical plate numbers up to 220 000 plates/m were achieved in the reversed phase separation of phenols. Poly(TFEM-co-EDMA) monolith also allowed the simultaneous separation of aniline and benzoic acid derivatives by a single run and by using a lower ACN concentration in the mobile phase with respect to the similar electrochromatographic separations. A stable retention behaviour in reversed phase separation of alkylbenzenes was obtained with the poly(TFEM-co-EDMA) monolith.

Estimation of methacrylate monolith binding capacity from pressure drop data.

PubMed

Podgornik, Aleš; Smrekar, Vida; Krajnc, Peter; Strancar, Aleš

2013-01-11

Convective chromatographic media comprising of membranes and monoliths represent an important group of chromatographic supports due to their flow-unaffected chromatographic properties and consequently fast separation and purification even of large biological macromolecules. Consisting of a single piece of material, common characterization procedures based on analysis of a small sample assuming to be representative for the entire batch, cannot be applied. Because of that, non-invasive characterization methods are preferred. In this work pressure drop was investigated for an estimation of dynamic binding capacity (DBC) of proteins and plasmid DNA for monoliths with different pore sizes. It was demonstrated that methacrylate monolith surface area is reciprocally proportional to pore diameter and that pressure drop on monolith is reciprocally proportional to square pore size demonstrating that methacrylate monolith microstructure is preserved by changing pore size. Based on these facts mathematical formalism has been derived predicting that DBC is in linear correlation with the square root of pressure drop. This was experimentally confirmed for ion-exchange and hydrophobic interactions for proteins and plasmid DNA. Furthermore, pressure drop was also applied for an estimation of DBC in grafted layers of different thicknesses as estimated from the pressure drop data. It was demonstrated that the capacity is proportional to the estimated grafted layer thickness. Copyright © 2012 Elsevier B.V. All rights reserved.

Facile preparation of a stable and functionalizable hybrid monolith via ring-opening polymerization for capillary liquid chromatography.

PubMed

Lin, Hui; Ou, Junjie; Tang, Shouwan; Zhang, Zhenbin; Dong, Jing; Liu, Zhongshan; Zou, Hanfa

2013-08-02

An organic-inorganic hybrid monolith was prepared by a single-step ring-opening polymerization of octaglycidyldimethylsilyl polyhedral oligomeric silsesquioxane (POSS) with poly(ethylenimine) (PEI). The obtained hybrid monoliths possessed high ordered 3D skeletal microstructure with dual retention mechanism that exhibits reversed-phase (RP) mechanism under polar mobile phase and hydrophilic-interaction liquid chromatography (HILIC) retention mechanism under less polar mobile phase. The high column efficiencies of 110,000N/m can be achieved for separation of alkylbenzenes in capillary reversed-phase liquid chromatography (cLC). Due to the robust property of hybrid monolith and the rich primary and secondary amino groups on its surface, the resulting hybrid monolith was easily modified with γ-gluconolactone and physically coated with cellulose tris(3,5-dimethylphenylcarbamate) (CDMPC), respectively. The former was successfully applied for HILIC separation of neutral, basic and acidic polar compounds as well as small peptides, and the latter for enantioseparation of racemates in cLC. The high column efficiencies were achieved in all of those separations. These results demonstrated that the hybrid monolith (POSS-PEI) possessed high stability and good surface tailorbility, potentially being applied for other research fields. Copyright © 2013 Elsevier B.V. All rights reserved.

A monolithic lipase reactor for biodiesel production by transesterification of triacylglycerides into fatty acid methyl esters

PubMed Central

Urban, Jiri; Svec, Frantisek; Fréchet, Jean M.J.

2011-01-01

An enzymatic reactor with lipase immobilized on a monolithic polymer support has been prepared and used to catalyze the transesterification of triacylglycerides into the fatty acid methyl esters commonly used for biodiesel. A design of experiments procedure was used to optimize the monolithic reactor with variables including control of the surface polarity of the monolith via variations in the length of the hydrocarbon chain in alkyl methacrylate monomer, time of grafting of 1-vinyl-4,4-dimethylazlactone used to activate the monolith, and time used for the immobilization of porcine lipase. Optimal conditions involved the use of a poly(stearyl methacrylate-co-ethylene dimethacrylate) monolith, grafted first with vinylazlactone, then treated with lipase for 2 h to carry out the immobilization of the enzyme. Best conditions for the transesterification of glyceryl tributyrate included a temperature of 37°C and a 10 min residence time of the substrate in the bioreactor. The reactor did not lose its activity even after pumping through it a solution of substrate equaling 1,000 reactor volumes. This enzymatic reactor was also used for the transesterification of triacylglycerides from soybean oil to fatty acid methyl esters thus demonstrating the ability of the reactor to produce biodiesel. PMID:21915852

A monolithic lipase reactor for biodiesel production by transesterification of triacylglycerides into fatty acid methyl esters.

PubMed

Urban, Jiri; Svec, Frantisek; Fréchet, Jean M J

2012-02-01

An enzymatic reactor with lipase immobilized on a monolithic polymer support has been prepared and used to catalyze the transesterification of triacylglycerides into the fatty acid methyl esters commonly used for biodiesel. A design of experiments procedure was used to optimize the monolithic reactor with variables including control of the surface polarity of the monolith via variations in the length of the hydrocarbon chain in alkyl methacrylate monomer, time of grafting of 1-vinyl-4,4-dimethylazlactone used to activate the monolith, and time used for the immobilization of porcine lipase. Optimal conditions involved the use of a poly(stearyl methacrylate-co-ethylene dimethacrylate) monolith, grafted first with vinylazlactone, then treated with lipase for 2 h to carry out the immobilization of the enzyme. Best conditions for the transesterification of glyceryl tributyrate included a temperature of 37°C and a 10 min residence time of the substrate in the bioreactor. The reactor did not lose its activity even after pumping through it a solution of substrate equaling 1,000 reactor volumes. This enzymatic reactor was also used for the transesterification of triacylglycerides from soybean oil to fatty acid methyl esters thus demonstrating the ability of the reactor to produce biodiesel. Copyright © 2011 Wiley Periodicals, Inc.

The 30-GHz monolithic receive module

NASA Technical Reports Server (NTRS)

Bauhahn, P.; Geddes, J.; Sokolov, V.; Contolatis, T.

1988-01-01

The fourth year progress is described on a program to develop a 27.5 to 30 GHz GaAs monolithic receive module for spaceborne-communication antenna feed array applications, and to deliver submodules for experimental evaluation. Program goals include an overall receive module noise figure of 5 dB, a 30 dB RF to IF gain with six levels of intermediate gain control, a five bit phase shifter, and a maximum power consumption of 250 mW. Submicron gate length single and dual gate FETs are described and applied in the development of monolithic gain control amplifiers and low noise amplifiers. A two-stage monolithic gain control amplifier based on ion implanted dual gate MESFETs was designed and fabricated. The gain control amplifier has a gain of 12 dB at 29 GHz with a gain control range of over 13 dB. A two-stage monolithic low noise amplifier based on ion implanted MESFETs which provides 7 dB gain with 6.2 dB noise figure at 29 GHz was also developed. An interconnected receive module containing LNA, gain control, and phase shifter submodules was built using the LNA and gain control ICs as well as a monolithic phase shifter developed previously under this program. The design, fabrication, and evaluation of this interconnected receiver is presented. Progress in the development of an RF/IF submodule containing a unique ion implanted diode mixer diode and a broadband balanced mixer monolithic IC with on-chip IF amplifier and the initial design of circuits for the RF portion of a two submodule receiver are also discussed.

Hybrid silica monolith for microextraction by packed sorbent to determine drugs from plasma samples by liquid chromatography-tandem mass spectrometry.

PubMed

de Souza, Israel D; Domingues, Diego S; Queiroz, Maria E C

2015-08-01

The present study (1) reports on the synthesis of two hybrid silica monoliths functionalized with aminopropyl or cyanopropyl groups by the sol-gel process; (2) evaluates these monoliths as selective stationary phase for microextraction by packed sorbent (MEPS) to determine drugs in plasma samples via liquid chromatography-tandem mass spectrometry (LC-MS/MS) in the multiple reactions monitoring (MRM) mode; and (3) discusses important factors related to the optimization of MEPS efficiency as well as the carryover effect. The prepared hybrid silica monoliths consisted of a uniform, porous, and continuous silica monolithic network. The structure of the aminopropyl hybrid silica monolith was more compact than the structure of the cyanopropyl hybrid silica monolith. The Fourier-transform infrared spectroscopy (FTIR) spectra of the hybrid silica monoliths displayed readily identifiable peaks, characteristic of the cyanopropyl and aminopropyl groups. Compared with the aminopropyl hybrid silica phase, the cyanopropyl hybrid silica phase exhibited higher binding capacity for most of the target drugs. The developed method afforded adequate linearity at concentrations ranging from the lower limit of quantification (0.05-1.00 ng mL(-1)) to the upper limit of quantification (40-10,500 ng mL(-1)); the coefficients of determination (r(2)) were higher than 0.9955. The precision of the method presented coefficients of variation (CV) lower than 14%; the relative standard error (RSE) of the accuracy ranged from -12% to 14%. The developed method allowed for simultaneous analysis of five antipsychotics (olanzapine, quetiapine, clozapine, haloperidol, and chlorpromazine) in combination with seven antidepressants (mirtazapine, paroxetine, citalopram, sertraline, imipramine, clomipramine, fluoxetine), two anticonvulsants (carbamazepine and lamotrigine), and two anxiolytics (diazepam and clonazepam) in plasma samples from schizophrenic patients, which should be valuable for therapeutic drug monitoring purposes. Copyright © 2015 Elsevier B.V. All rights reserved.

Constitutive model for porous materials

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

Weston, A.M.; Lee, E.L.

1982-01-01

A simple pressure versus porosity compaction model is developed to calculate the response of granular porous bed materials to shock impact. The model provides a scheme for calculating compaction behavior when relatively limited material data are available. While the model was developed to study porous explosives and propellants, it has been applied to a much wider range of materials. The early development of porous material models, such as that of Hermann, required empirical dynamic compaction data. Erkman and Edwards successfully applied the early theory to unreacted porous high explosives using a Gruneisen equation of state without yield behavior and withoutmore » trapped gas in the pores. Butcher included viscoelastic rate dependance in pore collapse. The theoretical treatment of Carroll and Holt is centered on the collapse of a circular pore and includes radial inertia terms and a complex set of stress, strain and strain rate constitutive parameters. Unfortunately data required for these parameters are generally not available. The model described here is also centered on the collapse of a circular pore, but utilizes a simpler elastic-plastic static equilibrium pore collapse mechanism without strain rate dependence, or radial inertia terms. It does include trapped gas inside the pore, a solid material flow stress that creates both a yield point and a variation in solid material pressure with radius. The solid is described by a Mie-Gruneisen type EOS. Comparisons show that this model will accurately estimate major mechanical features which have been observed in compaction experiments.« less

Water and Solute Mass Transport in Soils Developed on glacial Drift: A Br Tracer Investigation Using Instrumented Soil Monoliths at an Agricultural Long Term Ecological Research Site (Kellogg Biological Station, Hickory Corners, Southern Michigan)

NASA Astrophysics Data System (ADS)

Jin, L.; Hamilton, S. K.; Walter, L. M.

2004-12-01

Hydrologic processes control the residence time of water in the soil column. This is of central importance in understanding mineral weathering rates in terms of reaction kinetics and solute transport. In order to better quantify the coupling between water and solute mass transport and to better define controls on carbonate and aluminosilicates weathering rates, we have conducted bromide-tracer introduction experiments at four replicate soil monoliths (4 m3 volume) instrumented and managed by the KBS-LTER. Monolith soils are developed on the pitted outwash plain of the morainic system left by the last retreat of the Wisconsin glaciation, around 12,000 years ago. Soil profiles from the monolith sections extend to 200 cm and they were sampled and characterized texturally and mineralogically. Quartz and feldspar are dominant throughout the soil profile, while carbonates and hornblende occur only in deeper soil horizons. The four replicate monoliths are instrumented with gas and soil water sampling devices (Prenart tension lysimeters) at various depths. The monoliths also have a large capacity tray at the bottom, which permits collection of water for weight and chemical determinations. A bromide tracer solution (as lithium bromide) was applied to coincide as closely as possible with a major snowmelt event (2/27/04). The saturated and unsaturated transport of bromide through the four monoliths was followed as a function of time and soil profile depth for the duration of the snowmelt as well as intermittent rain events. Because the soil was saturated at the time of bromide application, the bromide solution is expected to move rapidly through macropores, followed by slower movement into micropores. The unsaturated transport of bromide is largely controlled by the intensity and duration of the rains if it is dominated by piston flow as opposed to preferential channel flow. In general, the tracer moved through the shallow soils very quickly, which is shown by early sharp peaks in bromide concentrations. Transport of bromide into deeper soil horizons, however, differs markedly among the four monoliths. Even within a given monolith, waters sampled at the same depth by different tension lysimeters show a very different pattern of bromide transport over time with some lyimeters suggesting piston flow, while others in the same monolith suggest preferential channel flow. These differences are likely driven by heterogeneous soil textures. The water recovered from the monolith trays over the first three months of the study period is between 80 and 90 percent of the total precipitation recorded at the LTER site. This recovery is reasonable given the fact that temperature was low and crops were not yet actively growing. The recovery of bromide is different among the monoliths and in general is less than 50 percent, which means more than 50 percent of tracer is still in the soils even after three months. Residence time of water has been calculated after some assumptions on the breakthrough curve. The water mass transport constraints imposed by the bromide tracer study will be utilized in concert with additional data on soil water geochemistry.

Designing, engineering, and testing wood structures

NASA Technical Reports Server (NTRS)

Gorman, Thomas M.

1992-01-01

The objective of this paper is to introduce basic structural engineering concepts in a clear, simple manner while actively involving students. This project emphasizes the fact that a good design uses materials efficiently. The test structure in this experiment can easily be built and has various design options. Even when the structure is loaded to collapsing, only one or two pieces usually break, leaving the remaining pieces intact and reusable.

A theoretical analysis of steady-state photocurrents in simple silicon diodes

NASA Technical Reports Server (NTRS)

Edmonds, L.

1995-01-01

A theoretical analysis solves for the steady-state photocurrents produced by a given photo-generation rate function with negligible recombination in simple silicon diodes, consisting of a uniformly doped quasi-neutral region (called 'substrate' below) adjacent to a p-n junction depletion region (DR). Special attention is given to conditions that produce 'funneling' (a term used by the single-eventeffects community) under steady-state conditions. Funneling occurs when carriers are generated so fast that the DR becomes flooded and partially or completely collapses. Some or nearly all of the applied voltage, plus built-in potential normally across the DR, is now across the substrate. This substrate voltage drop affects substrate currents. The steady-state problem can provide some qualitative insights into the more difficult transient problem. First, it was found that funneling can be induced from a distance, i.e., from carriers generated at locations outside of the DR. Secondly, it was found that the substrate can divide into two subregions, with one controlling substrate resistance and the other characterized by ambipolar diffusion. Finally, funneling was found to be more difficult to induce in the p(sup +)/n diode than in the n(sup +)/p diode. The carrier density exceeding the doping density in the substrate and at the DR boundary is not a sufficient condition to collapse a DR.

Monolithic ceramic capacitors for high reliability applications

NASA Technical Reports Server (NTRS)

Thornley, E. B.

1981-01-01

Monolithic multi-layer ceramic dielectric capacitors are widely used in high reliability applications in spacecraft, launch vehicles, and military equipment. Their relatively low cost, wide range of values, and package styles are attractive features that result in high usage in electronic circuitry in these applications. Design and construction of monolithic ceramic dielectric capacitors, defects that can lead to failure, and methods for defect detection that are being incorporated in military specifications are discussed.

Monolithic Gallium Arsenide Superheterodyne Front End.

DTIC Science & Technology

1982-06-01

which also provides a con - venient heat sink (not of primary importance in this application due to the low power dissipation of the monolithic...components utilized in the receiver front end). The thickness of the GaAs is then selected as a compromise between con - flicting requirements. A thick...International ERC41014.2FR 2.4 Analysis and Design for Low Noise The design of monolithic amplifiers for low noise must take into con - sideration active

Sol-Gel Synthesis of Non-Silica Monolithic Materials

PubMed Central

Gaweł, Bartłomiej; Gaweł, Kamila; Øye, Gisle

2010-01-01

Monolithic materials have become very popular because of various applications, especially within chromatography and catalysis. Large surface areas and multimodal porosities are great advantages for these applications. New sol-gel preparation methods utilizing phase separation or nanocasting have opened the possibility for preparing materials of other oxides than silica. In this review, we present different synthesis methods for inorganic, non-silica monolithic materials. Some examples of application of the materials are also included.

Monolithic multinozzle emitters for nanoelectrospray mass spectrometry

DOEpatents

Wang, Daojing [Daly City, CA; Yang, Peidong [Kensington, CA; Kim, Woong [Seoul, KR; Fan, Rong [Pasadena, CA

2011-09-20

Novel and significantly simplified procedures for fabrication of fully integrated nanoelectrospray emitters have been described. For nanofabricated monolithic multinozzle emitters (NM.sup.2 emitters), a bottom up approach using silicon nanowires on a silicon sliver is used. For microfabricated monolithic multinozzle emitters (M.sup.3 emitters), a top down approach using MEMS techniques on silicon wafers is used. The emitters have performance comparable to that of commercially-available silica capillary emitters for nanoelectrospray mass spectrometry.

Microchemical Systems and Their Applications Workshop Held on 16-18 June 1999 in Reston, Virginia

DTIC Science & Technology

2000-03-29

USABLE BY- PRODUCT HYDROGEN, BUT COST OF THE PT COATED CERAMIC TUBES IS HIGH, HEAT TRANSFER EFFICIENCY IS LIMITED, AND THE RISK ASSOCIATED WITH...Monolith reactor Monolith Catalyst A Gas mixture i quartz tube T 1 Radiation Shields GC / analysis 3M Monolith Catalysts *-v.V...polyamide. MicroChannel patterned laminates are fabricated from polyamide while microfin -patterned laminates are fabricated from copper. In addition to

Antibacterial activities effectuated by co-continuous epoxy-based polymer materials.

PubMed

Kubo, Takuya; Yasuda, Koji; Tominaga, Yuichi; Otsuka, Koji; Hosoya, Ken

2013-07-01

We report antibacterial activities of the epoxy-resin-based monolithic media (epoxy monoliths) having macroporous co-continuous structure as well as hydrophobic and/or hydrophilic surface. Utilizing epoxy monoliths containing ammonium groups, the antibacterial experiments were examined using Escherichia coli. As the results, the monolithic media prepared with an epoxy monomer having nitrogen atoms clearly showed antibacterial activities, while those prepared using the monomer without nitrogen atom showed less antibacterial activities. Additionally, the quaternization of the epoxy polymers were expressed significant antibacterial activities. Further studies elucidated that the observed antibacterial activities involved the steep effect based on pH changing of solution and hydrophobic interactions by the quaternary ammonium. Copyright © 2013 Elsevier B.V. All rights reserved.

Monolithic graphene transistor biointerface.

PubMed

Nam, SungWoo; Lee, Mi-Sun; Park, Jang-Ung

2012-01-01

We report monolithic integration of graphene and graphite for all-carbon integrated bioelectronics. First, we demonstrate that the electrical properties of graphene and graphite can be modulated by controlling the number of graphene layers, and such capabilities allow graphene to be used as active channels and graphite as metallic interconnects for all-carbon bioelectronics. Furthermore, we show that monolithic graphene-graphite devices exhibit mechanical flexibility and robustness while their electrical responses are not perturbed by mechanical deformation, demonstrating their unique electromechanical properties. Chemical sensing capability of all-carbon integrated bioelectronics is manifested in real-time, complementary pH detection. These unique capabilities of our monolithic graphene-graphite bioelectronics could be exploited in chemical and biological detection and conformal interface with biological systems in the future.

A monolithic integrated micro direct methanol fuel cell based on sulfo functionalized porous silicon

NASA Astrophysics Data System (ADS)

Wang, M.; Lu, Y. X.; Liu, L. T.; Wang, X. H.

2016-11-01

In this paper, we demonstrate a monolithic integrated micro direct methanol fuel cell (μDMFC) for the first time. The monolithic integrated μDMFC combines proton exchange membrane (PEM) and Pt nanocatalysts, in which PEM is achieved by the functionalized porous silicon membrane and 3D Pt nanoflowers being synthesized in situ on it as catalysts. Sulfo groups functionalized porous silicon membrane serves as a PEM and a catalyst support simultaneously. The μDMFC prototype achieves an open circuit voltage of 0.3 V, a maximum power density of 5.5 mW/cm2. The monolithic integrated μDMFC offers several desirable features such as compatibility with micro fabrication techniques, an undeformable solid PEM and the convenience of assembly.

On the suitability of Synbone® as a tissue simulant

NASA Astrophysics Data System (ADS)

Appleby-Thomas, Gareth; Fitzmaurice, Brianna; Hameed, Amer; Wood, David; Gibson, Mike; Painter, Jonathan

2015-06-01

The applicability of various materials as human tissue analogues has been a topic of increasing interest in recent years. It allows for more cost-effective experiments to be carried out, but also avoids ethical issues that would arise from using real human tissue. Synbone® , a porous polyurethane material, is commonly used in ballistic experiments as a bone simulant, but until now has not been characterised in terms of its dynamic behaviour. Here, the Hugoniot equation-of-state (EOS) for Synbone® has been derived via a series of plate-impact experiments; highlighting the importance of the underlying material structure in terms of material collapse under high strain-rates. A series of ballistic tests were also undertaken to provide further insight into the ballistic response of Synbone® and its potential role as a tissue simulant. This work - following on from previous in-house studies of other tissue analogues - has provided useful data for future simulation of this material. In addition, comparison to dynamic data for other tissue and simulant materials has highlighted the importance of considering tissue as non-monolithic; each layer of tissue should ideally be represented by its own simulant in ballistic experiments.

Monolithic spectrometer

DOEpatents

Rajic, Slobodan; Egert, Charles M.; Kahl, William K.; Snyder, Jr., William B.; Evans, III, Boyd M.; Marlar, Troy A.; Cunningham, Joseph P.

1998-01-01

A monolithic spectrometer is disclosed for use in spectroscopy. The spectrometer is a single body of translucent material with positioned surfaces for the transmission, reflection and spectral analysis of light rays.

Order-of-magnitude physics of neutron stars. Estimating their properties from first principles

NASA Astrophysics Data System (ADS)

Reisenegger, Andreas; Zepeda, Felipe S.

2016-03-01

We use basic physics and simple mathematics accessible to advanced undergraduate students to estimate the main properties of neutron stars. We set the stage and introduce relevant concepts by discussing the properties of "everyday" matter on Earth, degenerate Fermi gases, white dwarfs, and scaling relations of stellar properties with polytropic equations of state. Then, we discuss various physical ingredients relevant for neutron stars and how they can be combined in order to obtain a couple of different simple estimates of their maximum mass, beyond which they would collapse, turning into black holes. Finally, we use the basic structural parameters of neutron stars to briefly discuss their rotational and electromagnetic properties.

Effects of cementation surface modifications on fracture resistance of zirconia.

PubMed

Srikanth, Ramanathan; Kosmac, Tomaz; Della Bona, Alvaro; Yin, Ling; Zhang, Yu

2015-04-01

To examine the effects of glass infiltration (GI) and alumina coating (AC) on the indentation flexural load and four-point bending strength of monolithic zirconia. Plate-shaped (12 mm × 12 mm × 1.0 mm or 1.5 or 2.0 mm) and bar-shaped (4 mm × 3 mm × 25 mm) monolithic zirconia specimens were fabricated. In addition to monolithic zirconia (group Z), zirconia monoliths were glass-infiltrated or alumina-coated on their tensile surfaces to form groups ZGI and ZAC, respectively. They were also glass-infiltrated on their upper surfaces, and glass-infiltrated or alumina-coated on their lower (tensile) surfaces to make groups ZGI2 and ZAC2, respectively. For comparison, porcelain-veneered zirconia (group PVZ) and monolithic lithium disilicate glass-ceramic (group LiDi) specimens were also fabricated. The plate-shaped specimens were cemented onto a restorative composite base for Hertzian indentation using a tungsten carbide spherical indenter with a radius of 3.2mm. Critical loads for indentation flexural fracture at the zirconia cementation surface were measured. Strengths of bar-shaped specimens were evaluated in four-point bending. Glass infiltration on zirconia tensile surfaces increased indentation flexural loads by 32% in Hertzian contact and flexural strength by 24% in four-point bending. Alumina coating showed no significant effect on resistance to flexural damage of zirconia. Monolithic zirconia outperformed porcelain-veneered zirconia and monolithic lithium disilicate glass-ceramics in terms of both indentation flexural load and flexural strength. While both alumina coating and glass infiltration can be used to effectively modify the cementation surface of zirconia, glass infiltration can further increase the flexural fracture resistance of zirconia. Copyright © 2015 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Covalent attachment of polymeric monolith to polyether ether ketone (PEEK) tubing.

PubMed

Lv, Chunguang; Heiter, Jaana; Haljasorg, Tõiv; Leito, Ivo

2016-08-17

A new method of reproducible preparation of vinylic polymeric monolithic columns with a key step of covalently anchoring the monolith to PEEK surface is described. In order to chemically attach the polymer monolith to the tube wall, methacrylate functional groups were introduced onto PEEK surface by a three-step procedure, including surface etching, surface reduction and surface methacryloylation. The chemical state of the modified tubing surface was characterized by attenuated total reflectance infrared (ATR-IR) spectroscopy. It was found that the etching step is the key to successfully modifying the PEEK tubing surface. Poly(styrene-co-divinylbenzene) monoliths were in situ synthesized by thermally initiated free radical copolymerization within the confines of surface-vinylized PEEK tubings of dimensions close to ones conventionally used in HPLC and UHPLC (1.6 mm internal diameter, 10.0-12.5 cm length). Adhesion test was done by measuring the operating pressure drop, which the prepared stationary phases can withstand. Good pressure resistance, up to 140 bar/10 cm (flow rate 0.5 mL min(-1), acetonitrile as a mobile phase), indicates strong bonding of monolith to the tubing wall. The monolithic material was proven to have a permeability of 1.7 × 10 (-14) m(2), applying acetonitrile-water 70:30 (v/v) as a mobile phase. The column performance was reproducible from column to column and was evaluated via the isocratic separation of a series of alkylbenzenes in the reversed-phase mode (acetonitrile-water 70:30, v/v). The numbers of plates per meter at optimal flow rate were found to be between 26 000 and 32 000 for the different analytes. Copyright © 2016 Elsevier B.V. All rights reserved.

Measurement of the eddy diffusion term in chromatographic columns. I. Application to the first generation of 4.6mm I.D. monolithic columns.

PubMed

Gritti, Fabrice; Guiochon, Georges

2011-08-05

The corrected heights equivalent to a theoretical plate (HETP) of three 4.6mm I.D. monolithic Onyx-C(18) columns (Onyx, Phenomenex, Torrance, CA) of different lengths (2.5, 5, and 10 cm) are reported for retained (toluene, naphthalene) and non-retained (uracil, caffeine) small molecules. The moments of the peak profiles were measured according to the accurate numerical integration method. Correction for the extra-column contributions was systematically applied. The peak parking method was used in order to measure the bulk diffusion coefficients of the sample molecules, their longitudinal diffusion terms, and the eddy diffusion term of the three monolithic columns. The experimental results demonstrate that the maximum efficiency was 60,000 plates/m for retained compounds. The column length has a large impact on the plate height of non-retained species. These observations were unambiguously explained by a large trans-column eddy diffusion term in the van Deemter HETP equation. This large trans-rod eddy diffusion term is due to the combination of a large trans-rod velocity bias (≃3%), a small radial dispersion coefficient in silica monolithic columns, and a poorly designed distribution and collection of the sample streamlets at the inlet and outlet of the monolithic rod. Improving the performance of large I.D. monolithic columns will require (1) a detailed knowledge of the actual flow distribution across and along these monolithic rod and (2) the design of appropriate inlet and outlet distributors designed to minimize the nefarious impact of the radial flow heterogeneity on band broadening. Copyright © 2011 Elsevier B.V. All rights reserved.

Fracture resistance of implant- supported monolithic crowns cemented to zirconia hybrid-abutments: zirconia-based crowns vs. lithium disilicate crowns

PubMed Central

Nawafleh, Noor; Öchsner, Andreas; George, Roy

2018-01-01

PURPOSE The aim of this in vitro study was to investigate the fracture resistance under chewing simulation of implant-supported posterior restorations (crowns cemented to hybrid-abutments) made of different all-ceramic materials. MATERIALS AND METHODS Monolithic zirconia (MZr) and monolithic lithium disilicate (MLD) crowns for mandibular first molar were fabricated using computer-aided design/computer-aided manufacturing technology and then cemented to zirconia hybrid-abutments (Ti-based). Each group was divided into two subgroups (n=10): (A) control group, crowns were subjected to single load to fracture; (B) test group, crowns underwent chewing simulation using multiple loads for 1.2 million cycles at 1.2 Hz with simultaneous thermocycling between 5℃ and 55℃. Data was statistically analyzed with one-way ANOVA and a Post-Hoc test. RESULTS All tested crowns survived chewing simulation resulting in 100% survival rate. However, wear facets were observed on all the crowns at the occlusal contact point. Fracture load of monolithic lithium disilicate crowns was statistically significantly lower than that of monolithic zirconia crowns. Also, fracture load was significantly reduced in both of the all-ceramic materials after exposure to chewing simulation and thermocycling. Crowns of all test groups exhibited cohesive fracture within the monolithic crown structure only, and no abutment fractures or screw loosening were observed. CONCLUSION When supported by implants, monolithic zirconia restorations cemented to hybrid abutments withstand masticatory forces. Also, fatigue loading accompanied by simultaneous thermocycling significantly reduces the strength of both of the all-ceramic materials. Moreover, further research is needed to define potentials, limits, and long-term serviceability of the materials and hybrid abutments. PMID:29503716

Effects of cementation surface modifications on fracture resistance of zirconia

PubMed Central

Srikanth, Ramanathan; Kosmac, Tomaz; Bona, Alvaro Della; Yin, Ling; Zhang, Yu

2015-01-01

Objectives To examine the effects of glass infiltration (GI) and alumina coating (AC) on the indentation flexural load and four-point bending strength of monolithic zirconia. Methods Plate-shaped (12 mm × 12 mm × 1.0 mm or 1.5 mm or 2.0 mm) and bar-shaped (4 mm × 3 mm × 25 mm) monolithic zirconia specimens were fabricated. In addition to monolithic zirconia (group Z), zirconia monoliths were glass-infiltrated or alumina-coated on their tensile surfaces to form groups ZGI and ZAC, respectively. They were also glass-infiltrated on their upper surfaces, and glass-infiltrated or alumina-coated on their lower (tensile) surfaces to make groups ZGI2 and ZAC2, respectively. For comparison, porcelain-veneered zirconia (group PVZ) and monolithic lithium disilicate glass-ceramic (group LiDi) specimens were also fabricated. The plate-shaped specimens were cemented onto a restorative composite base for Hertzian indentation using a tungsten carbide spherical indenter with a radius of 3.2 mm. Critical loads for indentation flexural fracture at the zirconia cementation surface were measured. Strengths of bar-shaped specimens were evaluated in four-point bending. Results Glass infiltration on zirconia tensile surfaces increased indentation flexural loads by 32% in Hertzian contact and flexural strength by 24% in four-point bending. Alumina coating showed no significant effect on resistance to flexural damage of zirconia. Monolithic zirconia outperformed porcelain-veneered zirconia and monolithic lithium disilicate glass-ceramics in terms of both indentation flexural load and flexural strength. Significance While both alumina coating and glass infiltration can be used to effectively modify the cementation surface of zirconia, glass infiltration can further increase the flexural fracture resistance of zirconia. PMID:25687628

Influence of different approaches for dynamical performance optimization of monolithic passive colliding-pulse mode-locked laser diodes emitting around 850 nm

NASA Astrophysics Data System (ADS)

Prziwarka, T.; Klehr, A.; Wenzel, H.; Fricke, J.; Bugge, F.; Weyers, M.; Knigge, A.; Tränkle, G.

2018-02-01

Monolithic laser diodes which generate short infrared pulses in the picosecond and sub-picosecond ranges with high peak power are ideal sources for many applications like e.g. THz-time-domain spectroscopy (TDS) scanning systems. The achievable THz bandwidth is limited by the length of the optical pulses. Due to the fact that colliding-pulse mode locking (CPM) leads to the shortest pulses which could reached by passive mode locking, we experimentally investigated in detail the dynamical and electro optical performance of InGaAsP based quantum well CPM laser diodes with well-established vertical layer structures. Simple design modifications whose implementation is technically easy were realized. Improvements of the device performance in terms of pulse duration, output power, and noise properties are presented in dependence on the different adaptions. From the results we extract an optimized configuration with which we have reached pulses with durations of ≍1.5 ps, a peak power of > 1 W and a pulse-to-pulse timing jitter < 200 fs. The laser diodes emit pulses at a wavelength around 850 nm with a repetition frequency of ≍ 12.4 GHz and could be used as pump source for GaAs antennas to generate THz-radiation. Approaches for reducing pulse width, increasing output power, and improving noise performance are described.

All-round utilization of biomass derived all-solid-state asymmetric carbon-based supercapacitor.

PubMed

Wang, Chao; Xiong, Ye; Wang, Hanwei; Sun, Qingfeng

2018-05-30

All-round utilization of resources is proposed for maximizing environmental and economic benefits. Herein, the concept of all-round utilization on biomass derivations applying to carbon-based supercapacitors is demonstrated. Orange peel is used for all subassemblies of supercapacitor, including electrodes, separator and electrolyte. A monolithic porous carbon (OPHPC) is prepared by one-step carbonization of orange peel and another composite electrode is further synthesized by a simple hydrothermal process, based on sufficient utilization of natural structure and chemical components. OPHPC exhibits a high specific surface area of 860 m 2  g -1 and naturally doped nitrogen. The composite electrode shows the homogeneous and high mass loading of MnO 2 . Orange peel also affords the role of separator benefited from the natural porous channel structure and high porosity of 74.6%. Orange peel juice is exploited to produce the electrolyte, and exhibits the best retention in natural separator. All-orange peel all-solid-state supercapacitor shows the high areal capacitance of 3987 mF cm -2 . Furthermore, the flexibility of orange peel is also utilized to achieve the shape-tailored monolithic porous carbon electrode and device, which further extends the utilized dimensionality in biomass applying to supercapacitors. The work starts with all dimensional utilization for biomass derived supercapacitor. Copyright © 2018. Published by Elsevier Inc.

Modular Affective Reasoning-Based Versatile Introspective Architecture (MARVIN)

DTIC Science & Technology

2008-08-14

monolithic kernels found in most mass market OSs, where these kinds of system processes run within the kernel , and thus need to be highly optimized as well as...without modifying pre- existing process management elements, we expect the process of transitioning this component from MINIX to monolithic kernels to...necessary to incorporate them into a monolithic kernel . To demonstrate how the APMM would work in practice, we used it as the basis for building a simulated

The application of a monolithic triphenylphosphine reagent for conducting Ramirez gem-dibromoolefination reactions in flow.

PubMed

Roper, Kimberley A; Berry, Malcolm B; Ley, Steven V

2013-01-01

The application of a monolithic form of triphenylphosphine to the Ramirez gem-dibromoolefination reaction using flow chemistry techniques is reported. A variety of gem-dibromides were synthesised in high purity and excellent yield following only removal of solvent and no further off-line purification. It is also possible to perform the Appel reaction using the same monolith and the relationship between the mechanisms of the two reactions is discussed.

The application of a monolithic triphenylphosphine reagent for conducting Ramirez gem-dibromoolefination reactions in flow

PubMed Central

Roper, Kimberley A; Berry, Malcolm B

2013-01-01

Summary The application of a monolithic form of triphenylphosphine to the Ramirez gem-dibromoolefination reaction using flow chemistry techniques is reported. A variety of gem-dibromides were synthesised in high purity and excellent yield following only removal of solvent and no further off-line purification. It is also possible to perform the Appel reaction using the same monolith and the relationship between the mechanisms of the two reactions is discussed. PMID:24062843

Influence of the preparation design and artificial aging on the fracture resistance of monolithic zirconia crowns.

PubMed

Mitov, Gergo; Anastassova-Yoshida, Yana; Nothdurft, Frank Phillip; von See, Constantin; Pospiech, Peter

2016-02-01

The aim of this study was to evaluate the fracture resistance and fracture behavior of monolithic zirconia crowns in accordance with the preparation design and aging simulation method. An upper first molar was prepared sequentially with three different preparation designs: shoulderless preparation, 0.4 mm chamfer and 0.8 mm chamfer preparation. For each preparation design, 30 monolithic zirconia crowns were fabricated. After cementation on Cr-Co alloy dies, the following artificial aging procedures were performed: (1) thermal cycling and mechanical loading (TCML): 5000 cycles of thermal cycling 5℃-55℃ and chewing simulation (1,200,000 cycles, 50 N); (2) Low Temperature Degradation simulation (LTD): autoclave treatment at 137℃, 2 bar for 3 hours and chewing simulation; and (3) no pre-treatment (control group). After artificial aging, the crowns were loaded until fracture. The mean values of fracture resistance varied between 3414 N (LTD; 0.8 mm chamfer preparation) and 5712 N (control group; shoulderless preparation). Two-way ANOVA analysis showed a significantly higher fracture loads for the shoulderless preparation, whereas no difference was found between the chamfer preparations. In contrast to TCML, after LTD simulation the fracture strength of monolithic zirconia crowns decreased significantly. The monolithic crowns tested in this study showed generally high fracture load values. Preparation design and LTD simulation had a significant influence on the fracture strength of monolithic zirconia crowns.

Preparation of Ice-Templated MOF-Polymer Composite Monoliths and Their Application for Wastewater Treatment with High Capacity and Easy Recycling.

PubMed

Fu, Qingshan; Wen, Lang; Zhang, Lei; Chen, Xuedan; Pun, Daniel; Ahmed, Adham; Yang, Yonghong; Zhang, Haifei

2017-10-04

An ice-templating process was used to fabricate polymer/MOF monoliths, specifically chitosan/UiO-66, as adsorbents for water treatment. The ice-templated macropores enhanced mass transport, while the monoliths could be easily recovered from solution. This was demonstrated by the adsorption of methylchlorophenoxypropionic acid (MCPP, a herbicide compound) from dilute aqueous solution. To enhance the stability, the freeze-dried monoliths were treated with NaOH solution, solvent exchanged, and dried. The treated chitosan/UiO-66 monolith achieved an adsorption capacity of 34.33 mg g -1 (a maximum theoretic value of 334 mg g -1 by the Langmuir model), closer to the capacity (36.00 mg g -1 ) of the freshly prepared UiO-66 nanoparticles and much higher than that of the NaOH-washed UiO-66 nanoparticles (18.55 mg g -1 ), by performing the tests in 60 ppm MCPP solution. The composite monolith could be easily picked up using tweezers and used for recycling tests. Over 80% of the adsorption capacity was retained after three more cycles. The powder X-ray diffraction and N 2 sorption studies suggested the crystalline structure of UiO-66 was destroyed during NaOH washing procedure. This, however, provides the potential to improve the adsorption capacity by developing methods to fabricate true polymer/MOF composites.

Reliability and mode of failure of bonded monolithic and multilayer ceramics.

PubMed

Alessandretti, Rodrigo; Borba, Marcia; Benetti, Paula; Corazza, Pedro Henrique; Ribeiro, Raissa; Della Bona, Alvaro

2017-02-01

To evaluate the reliability of monolithic and multilayer ceramic structures used in the CAD-on technique (Ivoclar), and the mode of failure produced in ceramic structures bonded to a dentin analog material (NEMA-G10). Ceramic specimens were fabricated as follows (n=30): CAD-on- trilayer structure (IPS e.max ZirCAD/IPS e.max Crystall./Connect/IPS e.max CAD); YLD- bilayer structure (IPS e.max ZirCAD/IPS e.max Ceram); LDC- monolithic structure (IPS e.max CAD); and YZW- monolithic structure (Zenostar Zr Translucent). All ceramic specimens were bonded to G10 and subjected to compressive load in 37°C distilled water until the sound of the first crack, monitored acoustically. Failure load (L f ) values were recorded (N) and statistically analyzed using Weibull distribution, Kruskal-Wallis test, and Student-Newman-Keuls test (α=0.05). L f values of CAD-on and YZW structures were statistically similar (p=0.917), but higher than YLD and LDC (p<0.01). Weibull modulus (m) values were statistically similar for all experimental groups. Monolithic structures (LDC and YZW) failed from radial cracks. Failures in the CAD-on and YLD groups showed, predominantly, both radial and cone cracks. Monolithic zirconia (YZW) and CAD-on structures showed similar failure resistance and reliability, but a different fracture behavior. Copyright © 2016 The Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Potential for recovery of cerium contained in automotive catalytic converters

USGS Publications Warehouse

Bleiwas, Donald I.

2013-01-01

Catalytic converters (CATCONs) are required by Federal law to be installed in nearly all gasoline- and diesel-fueled onroad vehicles used in the United States. About 85 percent of the light-duty vehicles and trucks manufactured worldwide are equipped with CATCONs. Portions of the CATCONs (called monoliths) are recycled for their platinum-group metal (PGM) content and for the value of the stainless steel they contain. The cerium contained in the monoliths, however, is disposed of along with the slag produced from the recycling process. Although there is some smelter capacity in the United States to treat the monoliths in order to recover the PGMs, a great percentage of monoliths is exported to Europe and South Africa for recycling, and a lesser amount is exported to Japan. There is presently no commercial-scale capacity in place domestically to recover cerium from the monoliths. Recycling of cerium or cerium compounds from the monoliths could help ensure against possible global supply shortages by increasing the amount that is available in the supply chain as well as the number and geographic distribution of the suppliers. It could also reduce the amount of material that goes into landfills. Also, the additional supply could lower the price of the commodity. This report analyzes how much cerium oxide is contained in CATCONs and how much could be recovered from used CATCONs.

Characteristic of theophylline imprinted monolithic column and its application for determination of xanthine derivatives caffeine and theophylline in green tea.

PubMed

Sun, Han-wen; Qiao, Feng-xia; Liu, Guang-yu

2006-11-17

Theophylline imprinted monolithic columns were designed and prepared for rapid separation of a homologous series of xanthine derivatives, caffeine, and theophylline by an in situ thermal-initiated copolymerization technique. Caffeine and theophylline were fully separated both under isocratic and gradient elutions on this kind of monolithic molecularly imprinted polymers (MIP) column. The broad peak showed in isocratic elution could be improved in gradient elution. Some chromatographic conditions such as mobile phase composition, flow rate, and the temperature on the retention times were investigated. Hydrogen bonding interaction and hydrophobic interaction played an important role in the retention and separation. The binding capacity was evaluated by static adsorption and Scatchard analysis, which showed that the dissociation constant (KD) and the maximum binding capacity (Qmax) were 1.50 mol/L, and 236 micromol/g for high affinity binding site, and 7.97 mol/L and 785 micromol/g for lower affinity binding site, respectively. Thermodynamic data (DeltaDeltaH and DeltaDeltaS) obtained by Van't Hoff plots revealed an enthalpy-controlled separation. The morphological characteristics of monolithic MIP were investigated by scanning electron microscope, which showed that both mesopores and macropores were formed in the monolith. The present monolithic MIP column was successfully applied for the quantitative determination of caffeine and theophylline in different kinds of green tea.

Biomechanical three-dimensional finite element analysis of monolithic zirconia crown with different cement type

PubMed Central

2015-01-01

PURPOSE The objective of this study was to evaluate the influence of various cement types on the stress distribution in monolithic zirconia crowns under maximum bite force using the finite element analysis. MATERIALS AND METHODS The models of the prepared #46 crown (deep chamfer margin) were scanned and solid models composed of the monolithic zirconia crown, cement layer, and prepared tooth were produced using the computer-aided design technology and were subsequently translated into 3-dimensional finite element models. Four models were prepared according to different cement types (zinc phosphate, polycarboxylate, glass ionomer, and resin). A load of 700 N was applied vertically on the crowns (8 loading points). Maximum principal stress was determined. RESULTS Zinc phosphate cement had a greater stress concentration in the cement layer, while polycarboxylate cement had a greater stress concentration on the distal surface of the monolithic zirconia crown and abutment tooth. Resin cement and glass ionomer cement showed similar patterns, but resin cement showed a lower stress distribution on the lingual and mesial surface of the cement layer. CONCLUSION The test results indicate that the use of different luting agents that have various elastic moduli has an impact on the stress distribution of the monolithic zirconia crowns, cement layers, and abutment tooth. Resin cement is recommended for the luting agent of the monolithic zirconia crowns. PMID:26816578

Monolithic spectrometer

DOEpatents

Rajic, S.; Egert, C.M.; Kahl, W.K.; Snyder, W.B. Jr.; Evans, B.M. III; Marlar, T.A.; Cunningham, J.P.

1998-05-19

A monolithic spectrometer is disclosed for use in spectroscopy. The spectrometer is a single body of translucent material with positioned surfaces for the transmission, reflection and spectral analysis of light rays. 6 figs.

Preparation of well-controlled three-dimensional skeletal hybrid monoliths via thiol-epoxy click polymerization for highly efficient separation of small molecules in capillary liquid chromatography.

PubMed

Lin, Hui; Chen, Lianfang; Ou, Junjie; Liu, Zhongshan; Wang, Hongwei; Dong, Jing; Zou, Hanfa

2015-10-16

Two kinds of hybrid monoliths were first prepared via thiol-epoxy click polymerization using a multi-epoxy monomer, octaglycidyldimethylsilyl POSS (POSS-epoxy), and two multi-thiols, trimethylolpropanetris(3-mercaptopropionate) (TPTM) and pentaerythritoltetrakis(3-mercaptopropionate) (PTM), respectively, as the precursors. The resulting two hybrid monoliths (assigned as POSS-epoxy-TPTM and POSS-epoxy-PTM) not only possessed high thermal, mechanical and chemical stabilities, but also exhibited well-controlled 3D skeletal microstructure and high efficiency in capillary liquid chromatography (cLC) separation of small molecules. The highest column efficiency reached 182,700N/m (for butylbenzene) on the monolith POSS-epoxy-PTM at the velocity of 0.75mm/s. Furthermore, the hybrid monolith POSS-epoxy-PTM was successfully applied for cLC separations of various samples, not only standard compounds such as alkylbenzenes, PAHs, phenols and dipeptides, as well as intact proteins, but also complex samples of EPA 610 and BSA digest. Copyright © 2015 Elsevier B.V. All rights reserved.

Electrochemical properties of monolithic nickel sulfide electrodes for use in sodium batteries

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

Go, Dae-Yeon; Park, Jinsoo, E-mail: jsp@ikw.ac.kr; Noh, Pan-Jin

2014-10-15

Highlights: • We succeeded in preparing monolithic Ni{sub 3}S{sub 2} integrated electrode through the sulfuration. • The sulfuration is a facile and useful method to synthesize metal sulfides with nanostructure. • As-prepared monolithic Ni{sub 3}S{sub 2} electrodes showed very stable and cycle performance over charge/discharge cycling. - Abstract: Monolithic nickel sulfide electrodes were prepared using a facile synthesis method, sulfuration and annealing. As-prepared Ni{sub 3}S{sub 2} electrodes were characterized by X-ray diffractometry and field emission scanning electron microscopy. Thermal stability was determined by thermal gravimetric analysis and differential scanning calorimetry. Electrochemical properties were measured by galvanostatic charge and discharge cyclingmore » for Na-ion batteries. Three kinds of Ni{sub 3}S{sub 2} electrodes were prepared by varying the sulfuration time (5, 15 and 25 min). The electrochemical results indicated that the capacities increased with an increase in sulfuration time and the cycle performance was stable as a result of monolithic integration of nanostructured Ni{sub 3}S{sub 2} on Ni plates, leading to low interfacial resistance.« less

NASA developments in solid state power amplifiers

NASA Technical Reports Server (NTRS)

Leonard, Regis F.

1990-01-01

Over the last ten years, NASA has undertaken an extensive program aimed at development of solid state power amplifiers for space applications. Historically, the program may be divided into three phases. The first efforts were carried out in support of the advanced communications technology satellite (ACTS) program, which is developing an experimental version of a Ka-band commercial communications system. These first amplifiers attempted to use hybrid technology. The second phase was still targeted at ACTS frequencies, but concentrated on monolithic implementations, while the current, third phase, is a monolithic effort that focusses on frequencies appropriate for other NASA programs and stresses amplifier efficiency. The topics covered include: (1) 20 GHz hybrid amplifiers; (2) 20 GHz monolithic MESFET power amplifiers; (3) Texas Instruments' (TI) 20 GHz variable power amplifier; (4) TI 20 GHz high power amplifier; (5) high efficiency monolithic power amplifiers; (6) GHz high efficiency variable power amplifier; (7) TI 32 GHz monolithic power amplifier performance; (8) design goals for Hughes' 32 GHz variable power amplifier; and (9) performance goals for Hughes' pseudomorphic 60 GHz power amplifier.

Gel-based morphological design of zirconium metal-organic frameworks.

PubMed

Bueken, Bart; Van Velthoven, Niels; Willhammar, Tom; Stassin, Timothée; Stassen, Ivo; Keen, David A; Baron, Gino V; Denayer, Joeri F M; Ameloot, Rob; Bals, Sara; De Vos, Dirk; Bennett, Thomas D

2017-05-01

The ability of metal-organic frameworks (MOFs) to gelate under specific synthetic conditions opens up new opportunities in the preparation and shaping of hierarchically porous MOF monoliths, which could be directly implemented for catalytic and adsorptive applications. In this work, we present the first examples of xero- or aerogel monoliths consisting solely of nanoparticles of several prototypical Zr 4+ -based MOFs: UiO-66-X (X = H, NH 2 , NO 2 , (OH) 2 ), UiO-67, MOF-801, MOF-808 and NU-1000. High reactant and water concentrations during synthesis were observed to induce the formation of gels, which were converted to monolithic materials by drying in air or supercritical CO 2 . Electron microscopy, combined with N 2 physisorption experiments, was used to show that irregular nanoparticle packing leads to pure MOF monoliths with hierarchical pore systems, featuring both intraparticle micropores and interparticle mesopores. Finally, UiO-66 gels were shaped into monolithic spheres of 600 μm diameter using an oil-drop method, creating promising candidates for packed-bed catalytic or adsorptive applications, where hierarchical pore systems can greatly mitigate mass transfer limitations.

Scratch Testing of Hot-Pressed Monolithic Chromium Diboride (CrB2) and CrB2 + MoSi2 Composite

NASA Astrophysics Data System (ADS)

Bhatt, B.; Murthy, T. S. R. Ch.; Singh, K.; Sashanka, A.; Vishwanadh, B.; Sonber, J. K.; Sairam, K.; Nageswara Rao, G. V. S.; Srinivasa Rao, T.; Kain, Vivekanand

2017-10-01

The tribological performance of hot-pressed monolithic CrB2 and a newly developed CrB2 + 20 vol.% MoSi2 composite was investigated by using scratch test. The test was carried out under progressive loading ranging from 0.9 to 30 N over a scratch distance of 3 mm. In situ values of coefficient of friction (COF), depth of penetration and acoustic emission were recorded. The wear volume and fracture toughness were also calculated. COF of both materials is increased with increasing the scratch length and progressive load. COF of the composite was observed to be slightly higher compared to the monolithic CrB2. The wear volume of the composite is 60% higher compared to monolithic CrB2. Fracture toughness values of 2.48 and 2.81 MPa m1/2 were calculated for monolithic CrB2 and CrB2 + 20 vol.% MoSi2 composite, respectively. Microstructural characterization indicates that the abrasive wear is the dominant wear mechanism in both the materials.

Nano-array based monolithic catalysts: Concept, rational materials design and tunable catalytic performance

DOE PAGES

Ren, Zheng; Guo, Yanbing; Gao, Pu-Xian

2015-03-20

Monolithic catalysts, also known as structured catalysts, represent an important catalyst configuration widely used in automotive, chemical, and energy industries. However, several issues associated with washcoat based monolithic catalyst preparation are ever present, such as compromised materials utilization efficiency due to a less-than-ideal wash coating process, difficulty in precise and optimum microstructure control and lack of structure-property correlation. Here, in this mini-review, we introduce the concept of nano-array catalyst, a new type of monolithic catalyst featuring high catalyst utilization efficiency, good thermal/mechanical robustness, and catalytic performance tunability. A comprehensive overview is presented with detailed discussion of the strategies for nano-arraymore » catalyst preparation and rational catalytic activity adjustment enabled by the well-defined nano-array geometry. Specifically their scalable fabrication processes are reviewed in conjunction with discussion of their various catalytic oxidation reaction performances at low temperature. Finally, we hope this review will serve as a timely and useful research guide for rational design and utilization of the new type of monolithic catalysts.« less

Monolithically integrated quantum dot optical modulator with semiconductor optical amplifier for thousand and original band optical communication

NASA Astrophysics Data System (ADS)

Yamamoto, Naokatsu; Akahane, Kouichi; Umezawa, Toshimasa; Matsumoto, Atsushi; Kawanishi, Tetsuya

2016-04-01

A monolithically integrated quantum dot (QD) optical gain modulator (OGM) with a QD semiconductor optical amplifier (SOA) was successfully developed with T-band (1.0 µm waveband) and O-band (1.3 µm waveband) QD optical gain materials for Gbps-order, high-speed optical data generation. The insertion loss due to coupling between the device and the optical fiber was effectively compensated for by the SOA section. It was also confirmed that the monolithic QD-OGM/SOA device enabled >4.8 Gbps optical data generation with a clear eye opening in the T-band. Furthermore, we successfully demonstrated error-free 4.8 Gbps optical data transmissions in each of the six wavelength channels over a 10-km-long photonic crystal fiber using the monolithic QD-OGM/SOA device in multiple O-band wavelength channels, which were generated by the single QD gain chip. These results suggest that the monolithic QD-OGM/SOA device will be advantageous in ultra-broadband optical frequency systems that utilize the T+O-band for short- and medium-range optical communications.

Optimization of instantaneous solvent exchange/surface modification process for ambient synthesis of monolithic silica aerogels.

PubMed

Hwang, Sung-Woo; Kim, Tae-Youn; Hyun, Sang-Hoon

2008-06-01

The instantaneous solvent exchange/surface modification (ISE/SM) process for the ambient synthesis of crack-free silica aerogel monoliths with a high production yield was optimized. Monolithic forms of silica wet gels were obtained from aqueous colloidal silica sols prepared via the ion exchange of sodium silicate solutions. Crack-free silica aerogel monoliths were synthesized via an ISE/SM process using isopropyl alcohol/trimethylchlorosilane as a modification agent and n-hexane as a main solvent, followed by ambient drying. The optimum process conditions of the ISE/SM process were investigated by clarifying the reaction mechanism and phenomena. Most effective ranges of process variables on the ISE/SM stage were determined as 0.2500-0.3567 of TMCS/H2O (pore water) in molar ratio and 15-30 of n-hexane/TMCS in volumetric ratio, with a reaction temperature below 283 K. Crack-free silica aerogel monoliths synthesized via these conditions had a well-developed mesoporous structure and excellent properties (bulk density of 0.12-0.14 g/cm3, specific surface area of 724 m2/g), and a high yield (nearly 80%).

The Collapse of Vapor Bubbles in a Spatially Non-Uniform Flow

NASA Technical Reports Server (NTRS)

Hao, Y.; Prosperetti, A.

2000-01-01

Pressure gradients act differently on liquid particles and suspended bubbles and are, therefore, capable of inducing a relative motion between the phases even when no relative velocity initially exists. As a consequence of the enhanced heat transfer in the presence of convection, this fact may have a major impact on the evolution of a vapor bubble. The effect is particularly strong in the case of a collapsing bubble for which, due to the conservation of the system's impulse, the induced relative velocity tends to be magnified when the bubble volume shrinks. A practical application could be, for instance, the enhancement of the condensation rate of bubbles downstream of a heated region, thereby reducing the quality of a flowing liquid-vapor mixture. A simple model of the process, in which the bubble is assumed to be spherical and the flow potential, is developed in the paper.

Physics of Earthquake Disaster: From Crustal Rupture to Building Collapse

NASA Astrophysics Data System (ADS)

Uenishi, Koji

2018-05-01

Earthquakes of relatively greater magnitude may cause serious, sometimes unexpected failures of natural and human-made structures, either on the surface, underground, or even at sea. In this review, by treating several examples of extraordinary earthquake-related failures that range from the collapse of every second building in a commune to the initiation of spontaneous crustal rupture at depth, we consider the physical background behind the apparently abnormal earthquake disaster. Simple but rigorous dynamic analyses reveal that such seemingly unusual failures actually occurred for obvious reasons, which may remain unrecognized in part because in conventional seismic analyses only kinematic aspects of the effects of lower-frequency seismic waves below 1 Hz are normally considered. Instead of kinematics, some dynamic approach that takes into account the influence of higher-frequency components of waves over 1 Hz will be needed to anticipate and explain such extraordinary phenomena and mitigate the impact of earthquake disaster in the future.

Dykes and structures of the NE rift of Tenerife, Canary Islands: a record of stabilisation and destabilisation of ocean island rift zones

NASA Astrophysics Data System (ADS)

Delcamp, A.; Troll, V. R.; van Wyk de Vries, B.; Carracedo, J. C.; Petronis, M. S.; Pérez-Torrado, F. J.; Deegan, F. M.

2012-07-01

Many oceanic island rift zones are associated with lateral sector collapses, and several models have been proposed to explain this link. The North-East Rift Zone (NERZ) of Tenerife Island, Spain offers an opportunity to explore this relationship, as three successive collapses are located on both sides of the rift. We have carried out a systematic and detailed mapping campaign on the rift zone, including analysis of about 400 dykes. We recorded dyke morphology, thickness, composition, internal textural features and orientation to provide a catalogue of the characteristics of rift zone dykes. Dykes were intruded along the rift, but also radiate from several nodes along the rift and form en échelon sets along the walls of collapse scars. A striking characteristic of the dykes along the collapse scars is that they dip away from rift or embayment axes and are oblique to the collapse walls. This dyke pattern is consistent with the lateral spreading of the sectors long before the collapse events. The slump sides would create the necessary strike-slip movement to promote en échelon dyke patterns. The spreading flank would probably involve a basal decollement. Lateral flank spreading could have been generated by the intense intrusive activity along the rift but sectorial spreading in turn focused intrusive activity and allowed the development of deep intra-volcanic intrusive complexes. With continued magma supply, spreading caused temporary stabilisation of the rift by reducing slopes and relaxing stress. However, as magmatic intrusion persisted, a critical point was reached, beyond which further intrusion led to large-scale flank failure and sector collapse. During the early stages of growth, the rift could have been influenced by regional stress/strain fields and by pre-existing oceanic structures, but its later and mature development probably depended largely on the local volcanic and magmatic stress/strain fields that are effectively controlled by the rift zone growth, the intrusive complex development, the flank creep, the speed of flank deformation and the associated changes in topography. Using different approaches, a similar rift evolution has been proposed in volcanic oceanic islands elsewhere, showing that this model likely reflects a general and widespread process. This study, however, shows that the idea that dykes orient simply parallel to the rift or to the collapse scar walls is too simple; instead, a dynamic interplay between external factors (e.g. collapse, erosion) and internal forces (e.g. intrusions) is envisaged. This model thus provides a geological framework to understand the evolution of the NERZ and may help to predict developments in similar oceanic volcanoes elsewhere.

Posttest analysis of a laboratory-cast monolith of salt-saturated concrete. Final report

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

Wakeley, L.D.; Poole, T.S.

A salt-saturated concrete was formulated for laboratory testing of cementitious mixtures with potential for use in disposal of radioactive wastes in a geologic repository in halite rock. Cores were taken from a laboratory-cast concrete monolith on completion of tests of permeability, strain, and stress. The cores were analyzed for physical and chemical evidence of brine migration through the concrete, and other features with potential impact on installation of crete plugs at the Waste Isolation Pilot Plant (WIPP) in New Mexico. The posttest analyses of the cores provided evidence of brine movement along the interface between concrete and pipe, and littlemore » indication of permeability through the monolith itself. There may also have been diffusion of chloride into the monolith without actual brine flow.« less

High-density 3D graphene-based monolith and related materials, methods, and devices

DOEpatents

Worsley, Marcus A.; Baumann, Theodore F.; Biener, Juergen; Charnvanichborikarn, Supakit; Kucheyev, Sergei; Montalvo, Elizabeth; Shin, Swanee; Tylski, Elijah

2017-03-21

A composition comprising at least one high-density graphene-based monolith, said monolith comprising a three-dimensional structure of graphene sheets crosslinked by covalent carbon bonds and having a density of at least 0.1 g/cm.sup.3. Also provided is a method comprising: preparing a reaction mixture comprising a suspension and at least one catalyst, said suspension selected from a graphene oxide (GO) suspension and a carbon nanotube suspension; curing the reaction mixture to produce a wet gel; drying the wet gel to produce a dry gel, said drying step is substantially free of supercritical drying and freeze drying; and pyrolyzing the dry gel to produce a high-density graphene-based monolith. Exceptional combinations of properties are achieved including high conductive and mechanical properties.

Development of a monolithic ferrite memory array

NASA Technical Reports Server (NTRS)

Heckler, C. H., Jr.; Bhiwandker, N. C.

1972-01-01

The results of the development and testing of ferrite monolithic memory arrays are presented. This development required the synthesis of ferrite materials having special magnetic and physical characteristics and the development of special processes; (1) for making flexible sheets (laminae) of the ferrite composition, (2) for embedding conductors in ferrite, and (3) bonding ferrite laminae together to form a monolithic structure. Major problems encountered in each of these areas and their solutions are discussed. Twenty-two full-size arrays were fabricated and fired during the development of these processes. The majority of these arrays were tested for their memory characteristics as well as for their physical characteristics and the results are presented. The arrays produced during this program meet the essential goals and demonstrate the feasibility of fabricating monolithic ferrite memory arrays by the processes developed.

Comparative study of recent wide-pore materials of different stationary phase morphology, applied for the reversed-phase analysis of recombinant monoclonal antibodies.

PubMed

Fekete, Szabolcs; Veuthey, Jean-Luc; Eeltink, Sebastiaan; Guillarme, Davy

2013-04-01

Various recent wide-pore reversed-phase stationary phases were studied for the analysis of intact monoclonal antibodies (mAbs) of 150 kDa and their fragments possessing sizes between 25 and 50 kDa. Different types of column technology were evaluated, namely, a prototype silica-based inorganic monolith containing mesopores of ~250 Å and macropores of ~ 1.1 μm, a column packed with 3.6 μm wide-pore core-shell particles possessing a wide pore size distribution with an average around 200 Å and a column packed with fully porous 1.7 μm particles having pore size of ~300 Å. The performance of these wide-pore materials was compared with that of a poly(styrene-divinyl benzene) organic monolithic column, with a macropore size of approximately 1 μm but without mesopores (stagnant pores). A systematic investigation was carried out using model IgG1 and IgG2 mAbs, namely rituximab, panitumumab, and bevacizumab. Firstly, the recoveries of intact and reduced mAbs were compared on the two monolithic phases, and it appeared that adsorption was less pronounced on the organic monolith, probably due to the difference in chemistry (C18 versus phenyl) and the absence of mesopores (stagnant zones). Secondly, the kinetic performance was investigated in gradient elution mode for all columns. For this purpose, peak capacities per meter as well as peak capacities per time unit and per pressure unit (PPT) were calculated at various flow rates, to compare performance of columns with different dimensions. In terms of peak capacity per meter, the core-shell 3.6 μm and fully porous 1.7 μm columns outperformed the two monolithic phases, at a temperature of 60 °C. However, when considering the PPT values, the core-shell 3.6 μm column remained the best phase while the prototype silica-based monoliths became very interesting, mostly due to a very high permeability compared with the organic monolith. Therefore, these core-shell and silica-based monolith provided the fastest achievable separation. Finally, at the maximal working temperature of each column, the core-shell 3.6 μm column was far better than the other one, because it is the only one stable up to 90 °C. Lastly, the loading capacity was also measured on these four different phases. It appeared that the organic monolith was the less interesting and rapidly overloaded, due to the absence of mesopores. On the other hand, the loading capacity of prototype silica-based monolith was indeed reasonable.

Inefficient epidemic spreading in scale-free networks

NASA Astrophysics Data System (ADS)

Piccardi, Carlo; Casagrandi, Renato

2008-02-01

Highly heterogeneous degree distributions yield efficient spreading of simple epidemics through networks, but can be inefficient with more complex epidemiological processes. We study diseases with nonlinear force of infection whose prevalences can abruptly collapse to zero while decreasing the transmission parameters. We find that scale-free networks can be unable to support diseases that, on the contrary, are able to persist at high endemic levels in homogeneous networks with the same average degree.

Depth of interaction determination in monolithic scintillator with double side SiPM readout.

PubMed

Morrocchi, Matteo; Ambrosi, Giovanni; Bisogni, Maria Giuseppina; Bosi, Filippo; Boretto, Marco; Cerello, Piergiorgio; Ionica, Maria; Liu, Ben; Pennazio, Francesco; Piliero, Maria Antonietta; Pirrone, Giovanni; Postolache, Vasile; Wheadon, Richard; Del Guerra, Alberto

2017-12-01

Monolithic scintillators read out by arrays of photodetectors represent a promising solution to obtain high spatial resolution and the depth of interaction (DOI) of the annihilation photon. We have recently investigated a detector geometry composed of a monolithic scintillator readout on two sides by silicon photomultiplier (SiPM) arrays, and we have proposed two parameters for the DOI determination: the difference in the number of triggered SiPMs on the two sides of the detector and the difference in the maximum collected signal on a single SiPM on each side. This work is focused on the DOI calibration and on the determination of the capability of our detector. For the DOI calibration, we studied a method which can be implemented also in detectors mounted in a full PET scanner. We used a PET detector module composed of a monolithic 20 × 20 × 10 mm 3 LYSO scintillator crystal coupled on two opposite faces to two arrays of SiPMs. On each side, the scintillator was coupled to 6 × 6 SiPMs. In this paper, the two parameters previously proposed for the DOI determination were calibrated with two different methods. The first used a lateral scan of the detector with a collimated 511 keV pencil beam at steps of 0.5 mm to study the detector DOI capability, while the second used the background radiation of the 176 Lu in the scintillator. The DOI determination capability was tested on different regions of the detector using each parameter and the combination of the two. With both parameters for the DOI determination, in the lateral scan, the bias between the mean reconstructed DOI and the real beam position was lower than 0.3 mm, and the DOI distribution had a standard deviation of about 1.5 mm. When using the calibration with the radioactivity of the LYSO, the mean bias increased of about 0.2 mm but with no degradation of the standard deviation of the DOI distribution. The two parameters allow to achieve a DOI resolution comparable with the state of the art, giving a continuous information about the three-dimensional interaction position of the scintillation. These results were obtained by using simple estimators and a detector scalable to a whole PET system. The DOI calibration obtained using lutetium natural radioactivity gives results comparable to the other standard method but appears more readily applicable to detectors mounted in a full PET scanner.

A Space Imaging Concept Based on a 4-meter Spun-Cast Borosilicate Monolithic Primary Mirror

DTIC Science & Technology

2010-06-01

borosilicate monolithic primary mirror 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) Steve West, S.H... Mirror Technology Days, Boulder, Colorado, USA, 7-9 June 2010. 14. ABSTRACT The goal of this effort is to produce the largest monolithic telescope...capable of being lifted by a Delta IV or Atlas V EELV to 500 km. A strategy using a 4 m borosilicate mirror is proposed. A preliminary architecture was

Vertical Ge photodetector base on InP taper waveguide

NASA Astrophysics Data System (ADS)

Amiri, Iraj Sadegh; Ariannejad, M. M.; Azzuhri, S. R. B.; Anwar, T.; Kouhdaragh, V.; Yupapin, P.

2018-06-01

In this work, simulation is conducted to investigate Ge photodetectors monolithically integrated on Si chip. The performance of vertical Germanium photodetector with FDTD Solutions (optical simulation) and electrical simulation has been studied. Selective heteroepitaxy of Ge is functioned in the monolithic integration of Ge photodetectors. The potential of CMOS-compatible monolithic integration of Ge as photodetector is investigated and the performance optimization is presented. Additionally, the investigation is extended to electrical part, particularly in the conversion efficiency as well as operation under low supplied voltage condition.

Low frequency seismic noise acquisition and analysis with tunable monolithic horizontal sensors

NASA Astrophysics Data System (ADS)

Acernese, Fausto; De Rosa, Rosario; Giordano, Gerardo; Romano, Rocco; Vilasi, Silvia; Barone, Fabrizio

2011-04-01

In this paper we describe the scientific data recorded mechanical monolithic horizontal sensor prototypes located in the Gran Sasso Laboratory of the INFN. The mechanical monolithic sensors, developed at the University of Salerno, are placed, in thermally insulating enclosures, onto concrete slabs connected to the bedrock. The main goal of this experiment is to characterize seismically the sites in the frequency band 10-4 ÷ 10Hz and to get all the necessary information to optimize the sensor.

Mathematical Modelling of Optimization of Structures of Monolithic Coverings Based on Liquid Rubbers

NASA Astrophysics Data System (ADS)

Turgumbayeva, R. Kh; Abdikarimov, M. N.; Mussabekov, R.; Sartayev, D. T.

2018-05-01

The paper considers optimization of monolithic coatings compositions using a computer and MPE methods. The goal of the paper was to construct a mathematical model of the complete factorial experiment taking into account its plan and conditions. Several regression equations were received. Dependence between content components and parameters of rubber, as well as the quantity of a rubber crumb, was considered. An optimal composition for manufacturing the material of monolithic coatings compositions was recommended based on experimental data.

Fracture load of ceramic restorations after fatigue loading.

PubMed

Baladhandayutham, Balasudha; Lawson, Nathaniel C; Burgess, John O

2015-08-01

A clinician must decide what ceramic coping and veneer material to prescribe based on the amount of tooth reduction possible and the desired esthetic outcome of the restoration. The purpose of this in vitro study was to compare the fracture strength of monolithic and bilayered lithium disilicate (IPS e.max) and zirconia (LAVA) crowns at clinically relevant thicknesses after load cycling. Crowns (n=8) were fabricated from 6 groups: 1.2-mm monolithic lithium disilicate, 1.5-mm monolithic lithium disilicate, 1.5-mm bilayered lithium disilicate with hand-layered veneer, 0.6 mm monolithic zirconia, 1.2-mm bilayered zirconia with hand-layered veneer, and 1.2-mm bilayered zirconia with milled veneer (dimension represents thickness at the occlusal pit). Crowns were cemented to identical milled resin dies with resin-modified glass ionomer cement. Cemented crowns were stored at 37°C for 24 hours and load cycled for 200,000 cycles at 25 N at a rate of 40 cycles/minute. The ultimate fracture load for each specimen was measured in a universal testing machine. Data were analyzed with a 1-way ANOVA and Tukey honest significant difference post hoc analysis (α=.05). Mean ±SD fracture load values were 1465 ±330 N for monolithic lithium disilicate (1.2-mm thickness) and 2027 ±365 N (1.5-mm thickness) and 1732 ±315 N for bilayered hand-veneered lithium disilicate (1.5-mm thickness). Fracture loads were 1669 ±311 N for monolithic zirconia crowns (0.6mm thickness), 2625 ±300 N for zirconia milled-veneered (1.2-mm thickness), and 2655 ±590N for zirconia hand-veneered crowns (1.2mm thickness). One-way ANOVA showed a statistically significant difference among the groups (P<.01). Veneered zirconia crowns showed the highest fracture strength, 1.2-mm hand veneered zirconia was similar to that of 1.5-mm monolithic zirconia, and all other groups were not statistically different. Crowns of 1.2-mm bilayered zirconia had higher fracture loads than 0.6-mm zirconia or 1.2-mm lithium disilicate monolithic crowns. Copyright © 2015 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

Poly(ethylenimine)-Functionalized Monolithic Alumina Honeycomb Adsorbents for CO2 Capture from Air.

PubMed

Sakwa-Novak, Miles A; Yoo, Chun-Jae; Tan, Shuai; Rashidi, Fereshteh; Jones, Christopher W

2016-07-21

The development of practical and effective gas-solid contactors is an important area in the development of CO2 capture technologies. Target CO2 capture applications, such as postcombustion carbon capture and sequestration (CCS) from power plant flue gases or CO2 extraction directly from ambient air (DAC), require high flow rates of gas to be processed at low cost. Extruded monolithic honeycomb structures, such as those employed in the catalytic converters of automobiles, have excellent potential as structured contactors for CO2 adsorption applications because of the low pressure drop imposed on fluid moving through the straight channels of such structures. Here, we report the impregnation of poly(ethylenimine) (PEI), an effective aminopolymer reported commonly for CO2 separation, into extruded monolithic alumina to form structured CO2 sorbents. These structured sorbents are first prepared on a small scale, characterized thoroughly, and compared with powder sorbents with a similar composition. Despite consistent differences observed in the filling of mesopores with PEI between the monolithic and powder sorbents, their performance in CO2 adsorption is similar across a range of PEI contents. A larger monolithic cylinder (1 inch diameter, 4 inch length) is evaluated under conditions closer to those that might be used in large-scale applications and shows a similar performance to the smaller monoliths and powders tested initially. This larger structure is evaluated over five cycles of CO2 adsorption and steam desorption and demonstrates a volumetric capacity of 350 molCO2  m-3monolith and an equilibration time of 350 min under a 0.4 m s(-1) linear flow velocity through the monolith channels using 400 ppm CO2 in N2 as the adsorption gas at 30 °C. This volumetric capacity surpasses that of a similar technology considered previously, which suggested that CO2 could be removed from air at an operating cost as low as $100 per ton. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

High-speed logic integrated circuits with solution-processed self-assembled carbon nanotubes

NASA Astrophysics Data System (ADS)

Han, Shu-Jen; Tang, Jianshi; Kumar, Bharat; Falk, Abram; Farmer, Damon; Tulevski, George; Jenkins, Keith; Afzali, Ali; Oida, Satoshi; Ott, John; Hannon, James; Haensch, Wilfried

2017-09-01

As conventional monolithic silicon technology struggles to meet the requirements for the 7-nm technology node, there has been tremendous progress in demonstrating the scalability of carbon nanotube field-effect transistors down to the size that satisfies the 3-nm node and beyond. However, to date, circuits built with carbon nanotubes have overlooked key aspects of a practical logic technology and have stalled at simple functionality demonstrations. Here, we report high-performance complementary carbon nanotube ring oscillators using fully manufacturable processes, with a stage switching frequency of 2.82 GHz. The circuit was built on solution-processed, self-assembled carbon nanotube arrays with over 99.9% semiconducting purity, and the complementary feature was achieved by employing two different work function electrodes.

High-speed logic integrated circuits with solution-processed self-assembled carbon nanotubes.

PubMed

Han, Shu-Jen; Tang, Jianshi; Kumar, Bharat; Falk, Abram; Farmer, Damon; Tulevski, George; Jenkins, Keith; Afzali, Ali; Oida, Satoshi; Ott, John; Hannon, James; Haensch, Wilfried

2017-09-01

As conventional monolithic silicon technology struggles to meet the requirements for the 7-nm technology node, there has been tremendous progress in demonstrating the scalability of carbon nanotube field-effect transistors down to the size that satisfies the 3-nm node and beyond. However, to date, circuits built with carbon nanotubes have overlooked key aspects of a practical logic technology and have stalled at simple functionality demonstrations. Here, we report high-performance complementary carbon nanotube ring oscillators using fully manufacturable processes, with a stage switching frequency of 2.82 GHz. The circuit was built on solution-processed, self-assembled carbon nanotube arrays with over 99.9% semiconducting purity, and the complementary feature was achieved by employing two different work function electrodes.

Wavelength locking of CW and Q-switched Er(3+) microchip lasers to acetylene absorption lines using pump-power modulation.

PubMed

Brunel, Marc; Vallet, Marc

2007-02-19

We show that modulating the diode-pump power of a microchip solid-state laser enables to lock its wavelength to a reference molecular line. The method is applied to two different types of Er,Yb:glass monolithic microchip lasers operating at 1.53 microm. First, wavelength locking of a continuous-wave dual-polarization microchip laser to acetylene absorption lines is demonstrated, without using any additional modulator, internal or external. We then show that, remarkably, this simple method is also suitable for stabilizing a passively Q-switched microchip laser. A pulsed wavelength stability of 10(-8) over 1 hour is readily observed. Applications to lidars and to microwave photonics are discussed.

Solid optical ring interferometer for high-throughput feedback-free spectral analysis and filtering

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

Petrak, B.; Peiris, M.; Muller, A., E-mail: mullera@usf.edu

2015-02-15

We describe a simple and inexpensive optical ring interferometer for use in high-resolution spectral analysis and filtering. It consists of a solid cuboid, reflection-coated on two opposite sides, in which constructive interference occurs for waves in a rhombic trajectory. Due to its monolithic design, the interferometer’s resonance frequencies are insensitive to environmental disturbances over time. Additional advantages are its simplicity of alignment, high-throughput, and feedback-free operation. If desired, it can be stabilized with a secondary laser without disturbance of the primary signal. We illustrate the use of the interferometer for the measurement of the spectral Mollow triplet from a quantummore » dot and characterize its long-term stability for filtering applications.« less

New semiconductor laser technology for gas sensing applications in the 1650nm range

NASA Astrophysics Data System (ADS)

Morrison, Gordon B.; Sherman, Jes; Estrella, Steven; Moreira, Renan L.; Leisher, Paul O.; Mashanovitch, Milan L.; Stephen, Mark; Numata, Kenji; Wu, Stewart; Riris, Haris

2017-08-01

Atmospheric methane (CH4) is the second most important anthropogenic greenhouse gas with approximately 25 times the radiative forcing of carbon dioxide (CO2) per molecule. CH4 also contributes to pollution in the lower atmosphere through chemical reactions leading to ozone production. Recent developments of LIDAR measurement technology for CH4 have been previously reported by Goddard Space Flight Center (GSFC). In this paper, we report on a novel, high-performance tunable semiconductor laser technology developed by Freedom Photonics for the 1650nm wavelength range operation, and for LIDAR detection of CH4. Devices described are monolithic, with simple control, and compatible with low-cost fabrication techniques. We present 3 different types of tunable lasers implemented for this application.

The Last Minutes of Oxygen Shell Burning in a Massive Star

NASA Astrophysics Data System (ADS)

Müller, Bernhard; Viallet, Maxime; Heger, Alexander; Janka, Hans-Thomas

2016-12-01

We present the first 4π-three-dimensional (3D) simulation of the last minutes of oxygen shell burning in an 18 M ⊙ supernova progenitor up to the onset of core collapse. A moving inner boundary is used to accurately model the contraction of the silicon and iron core according to a one-dimensional stellar evolution model with a self-consistent treatment of core deleptonization and nuclear quasi-equilibrium. The simulation covers the full solid angle to allow the emergence of large-scale convective modes. Due to core contraction and the concomitant acceleration of nuclear burning, the convective Mach number increases to ˜0.1 at collapse, and an ℓ = 2 mode emerges shortly before the end of the simulation. Aside from a growth of the oxygen shell from 0.51 M ⊙ to 0.56 M ⊙ due to entrainment from the carbon shell, the convective flow is reasonably well described by mixing-length theory, and the dominant scales are compatible with estimates from linear stability analysis. We deduce that artificial changes in the physics, such as accelerated core contraction, can have precarious consequences for the state of convection at collapse. We argue that scaling laws for the convective velocities and eddy sizes furnish good estimates for the state of shell convection at collapse and develop a simple analytic theory for the impact of convective seed perturbations on shock revival in the ensuing supernova. We predict a reduction of the critical luminosity for explosion by 12%-24% due to seed asphericities for our 3D progenitor model relative to the case without large seed perturbations.

On the Maximum Mass of Accreting Primordial Supermassive Stars

NASA Astrophysics Data System (ADS)

Woods, T. E.; Heger, Alexander; Whalen, Daniel J.; Haemmerlé, Lionel; Klessen, Ralf S.

2017-06-01

Supermassive primordial stars are suspected to be the progenitors of the most massive quasars at z ˜ 6. Previous studies of such stars were either unable to resolve hydrodynamical timescales or considered stars in isolation, not in the extreme accretion flows in which they actually form. Therefore, they could not self-consistently predict their final masses at collapse, or those of the resulting supermassive black hole seeds, but rather invoked comparison to simple polytropic models. Here, we systematically examine the birth, evolution, and collapse of accreting, non-rotating supermassive stars under accretion rates of 0.01-10 M ⊙ yr-1 using the stellar evolution code Kepler. Our approach includes post-Newtonian corrections to the stellar structure and an adaptive nuclear network and can transition to following the hydrodynamic evolution of supermassive stars after they encounter the general relativistic instability. We find that this instability triggers the collapse of the star at masses of 150,000-330,000 M ⊙ for accretion rates of 0.1-10 M ⊙ yr-1, and that the final mass of the star scales roughly logarithmically with the rate. The structure of the star, and thus its stability against collapse, is sensitive to the treatment of convection and the heat content of the outer accreted envelope. Comparison with other codes suggests differences here may lead to small deviations in the evolutionary state of the star as a function of time, that worsen with accretion rate. Since the general relativistic instability leads to the immediate death of these stars, our models place an upper limit on the masses of the first quasars at birth.

Monolithic Active Pixel Sensors

NASA Astrophysics Data System (ADS)

Lutz, P.

In close collaboration with the group from Strasbourg, Saclay has been developing fast monolithic active pixel sensors for future vertex detectors. This presentation gives some recent results from the MIMOSA serie, emphazising the participation of the group.

Monolithic Perovskite Silicon Tandem Solar Cells with Advanced Optics

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

Goldschmidt, Jan C.; Bett, Alexander J.; Bivour, Martin

2016-11-14

For high efficiency monolithic perovskite silicon tandem solar cells, we develop low-temperature processes for the perovskite top cell, rear-side light trapping, optimized perovskite growth, transparent contacts and adapted characterization methods.

Eigenpolarization theory of monolithic nonplanar ring oscillators

NASA Technical Reports Server (NTRS)

Nilsson, Alan C.; Gustafson, Eric K.; Byer, Robert L.

1989-01-01

Diode-laser-pumped monolithic nonplanar ring oscillators (NPROs) in an applied magnetic field can operate as unidirectional traveling-wave lasers. The diode laser pumping, monolithic construction, and unidirectional oscillation lead to narrow linewidth radiation. Here, a comprehensive theory of the eigenpolarizations of a monolithic NPRO is presented. It is shown how the properties of the integral optical diode that forces unidirectional operation depend on the choice of the gain medium, the applied magnetic field, the output coupler, and the geometry of the nonplanar ring light path. Using optical equivalence theorems to gain insight into the polarization characteristics of the NPRO, a strategy for designing NPROs with low thresholds and large loss nonreciprocities is given. An analysis of the eigenpolarizations for one such NPRO is presented, alternative optimization approaches are considered, and the prospects for further reducing the linewidths of these lasers are briefly discussed.

Synthesis of transparent nanocomposite monoliths for gamma scintillation

NASA Astrophysics Data System (ADS)

Liu, Chao; Hajagos, Tibor J.; Kishpaugh, David; Jin, Yunxia; Hu, Wei; Chen, Qi; Pei, Qibing

2015-08-01

During the past decade, inorganic nanoparticles/polymer nanocomposites have been intensively studied to provide a low cost, high performance alternative for gamma scintillation. However, the aggregation of nanoparticles often occurs even at low nanoparticle concentrations and thus deteriorates the transparency and performance of these nanocomposite scintillators. Here we report an efficient fabrication protocol of transparent nanocomposite monoliths based on surface modified hafnium oxide nanoparticles. Using hafnium oxide nanoparticles with surface-grafted methacrylate groups, highly transparent bulk-size nanocomposite monoliths (2 mm thick, transmittance at 550 nm >75%) are fabricated with nanoparticle loadings up to 40 wt% (net hafnium wt% up to 28.5%). These nanocomposite monoliths of 1 cm diameter and 2 mm thickness are capable of producing a full energy photopeak for 662 keV gamma rays, with the best deconvoluted photopeak energy resolution reaching 8%.

Triazine herbicide imprinted monolithic column for capillary electrochromatography.

PubMed

Aşır, Süleyman; Derazshamshir, Ali; Yılmaz, Fatma; Denizli, Adil

2015-12-01

Trietazine was selectively separated from aqueous solution containing the competitor molecule cyanazine, which is similar in size and shape to the template molecule. Structural features of the molecularly imprinted column were figured out by SEM. The influence of the mobile-phase composition, applied electrical field, and pH of the mobile phase on the recognition of trietazine by the imprinted monolithic polymer has been evaluated, and the imprint effect in the trietazine-imprinted monolithic polymer was demonstrated by an imprinting factor. The optimized monolithic column resulted in separation of trietazine from a structurally related competitor molecule, cyanazine. In addition, fast separation was obtained within 6 min by applying higher electrical field, with the electrophoretic mobility of 2.97 × 10(-8) m(2) V(-1) s(-1) at pH 11.0. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Recent progress in low-temperature-process monolithic three dimension technology

NASA Astrophysics Data System (ADS)

Yang, Chih-Chao; Hsieh, Tung-Ying; Huang, Wen-Hsien; Shen, Chang-Hong; Shieh, Jia-Min; Yeh, Wen-Kuan; Wu, Meng-Chyi

2018-04-01

Monolithic three-dimension (3D) integration is an ultimate alternative method of fabricating high density, high performance, and multi-functional integrated circuits. It offers the promise of being a new approach to increase system performance. How to manage the thermal impact of multi-tiered processes, such as dopant activation, source/drain silicidation, and channel formation, and to prevent the degradation of pre-existing devices/circuits become key challenges. In this paper, we provide updates on several important monolithic 3D works, particularly in sequentially stackable channels, and our recent achievements in monolithic 3D integrated circuit (3D-IC). These results indicate that the advanced 3D architecture with novel design tools enables ultrahigh-density stackable circuits to have superior performance and low power consumption for future artificial intelligence (AI) and internet of things (IoTs) application.

Fabrication of CMC-g-PAM superporous polymer monoliths via eco-friendly Pickering-MIPEs for superior adsorption of methyl violet and methylene blue

NASA Astrophysics Data System (ADS)

Wang, Feng; Zhu, Yongfeng; Wang, Wenbo; Zong, Li; Lu, Taotao; Wang, Aiqin

2017-06-01

A series of superporous carboxymethylcellulose-graft-poly(acrylamide) (CMC-g-PAM) polymer monoliths presenting interconnected pore structure and excellent adsorption properties were prepared by one-step free-radical grafting polymerization reaction of CMC and acrylamide (AM) in the oil-in-water (O/W) Pickering-medium internal phase emulsions (Pickering-MIPEs) composed of non-toxic edible oil as a dispersion phase and natural Pal nanorods as stabilizers. The effects of Pal dosage, AM dosage, and co-surfactant Tween-20 (T-20) on the pore structures of the monoliths were studied. It was revealed that the well-defined pores were formed when the dosages of Pal and T-20 are 9-14% and 3%, respectively. The porous monolith can rapidly adsorb 1585 mg/g of methyl violet (MV) and 1625 mg/g of methylene blue (MB). After the monolith was regenerated by adsorption-desorption process for 5 times, the adsorption capacities still reached 92.1% (for MV) and 93.5% (for MB) of the initial maximum adsorption capacities. The adsorption process was fitted with Langmuir adsorption isotherm model and pseudo-second-order adsorption kinetic model very well, which indicate that mono-layer chemical adsorption mainly contribute to the high-capacity adsorption for dyes. The superporous polymer monolith prepared from eco-friendly Pickering-MIPEs shows good adsorption capacity and fast adsorption rate, which is potential adsorbent for the decontimination of dye-containing wastewater.

Influence of the preparation design and artificial aging on the fracture resistance of monolithic zirconia crowns

PubMed Central

Anastassova-Yoshida, Yana; Nothdurft, Frank Phillip; von See, Constantin; Pospiech, Peter

2016-01-01

PURPOSE The aim of this study was to evaluate the fracture resistance and fracture behavior of monolithic zirconia crowns in accordance with the preparation design and aging simulation method. MATERIALS AND METHODS An upper first molar was prepared sequentially with three different preparation designs: shoulderless preparation, 0.4 mm chamfer and 0.8 mm chamfer preparation. For each preparation design, 30 monolithic zirconia crowns were fabricated. After cementation on Cr-Co alloy dies, the following artificial aging procedures were performed: (1) thermal cycling and mechanical loading (TCML): 5000 cycles of thermal cycling 5℃–55℃ and chewing simulation (1,200,000 cycles, 50 N); (2) Low Temperature Degradation simulation (LTD): autoclave treatment at 137℃, 2 bar for 3 hours and chewing simulation; and (3) no pre-treatment (control group). After artificial aging, the crowns were loaded until fracture. RESULTS The mean values of fracture resistance varied between 3414 N (LTD; 0.8 mm chamfer preparation) and 5712 N (control group; shoulderless preparation). Two-way ANOVA analysis showed a significantly higher fracture loads for the shoulderless preparation, whereas no difference was found between the chamfer preparations. In contrast to TCML, after LTD simulation the fracture strength of monolithic zirconia crowns decreased significantly. CONCLUSION The monolithic crowns tested in this study showed generally high fracture load values. Preparation design and LTD simulation had a significant influence on the fracture strength of monolithic zirconia crowns. PMID:26949485

Fabrication of CMC-g-PAM Superporous Polymer Monoliths via Eco-Friendly Pickering-MIPEs for Superior Adsorption of Methyl Violet and Methylene Blue

PubMed Central

Wang, Feng; Zhu, Yongfeng; Wang, Wenbo; Zong, Li; Lu, Taotao; Wang, Aiqin

2017-01-01

A series of superporous carboxymethylcellulose-graft-poly(acrylamide)/palygorskite (CMC-g-PAM/Pal) polymer monoliths presenting interconnected pore structure and excellent adsorption properties were prepared by one-step free-radical grafting polymerization reaction of CMC and acrylamide (AM) in the oil-in-water (O/W) Pickering-medium internal phase emulsions (Pickering-MIPEs) composed of non-toxic edible oil as a dispersion phase and natural Pal nanorods as stabilizers. The effects of Pal dosage, AM dosage, and co-surfactant Tween-20 (T-20) on the pore structures of the monoliths were studied. It was revealed that the well-defined pores were formed when the dosages of Pal and T-20 are 9–14 and 3%, respectively. The porous monolith can rapidly adsorb 1,585 mg/g of methyl violet (MV) and 1,625 mg/g of methylene blue (MB). After the monolith was regenerated by adsorption-desorption process for five times, the adsorption capacities still reached 92.1% (for MV) and 93.5% (for MB) of the initial maximum adsorption capacities. The adsorption process was fitted with Langmuir adsorption isotherm model and pseudo-second-order adsorption kinetic model very well, which indicate that mono-layer chemical adsorption mainly contribute to the high-capacity adsorption for dyes. The superporous polymer monolith prepared from eco-friendly Pickering-MIPEs shows good adsorption capacity and fast adsorption rate, which is potential adsorbent for the decontamination of dye-containing wastewater. PMID:28642862

In vitro analysis of the fracture resistance of CAD-CAM monolithic zirconia molar crowns with different occlusal thickness.

PubMed

Sorrentino, Roberto; Triulzio, Clementina; Tricarico, Maria Gabriella; Bonadeo, Giovanni; Gherlone, Enrico Felice; Ferrari, Marco

2016-08-01

To compare the fracture resistance and mode of failure of CAD-CAM monolithic zirconia crowns with different occlusal thickness. Forty CAD-CAM monolithic zirconia crowns with different occlusal thickness were randomly distributed into 4 experimental groups: 2.0mm (group 1), 1.5mm (group 2), 1.0mm (group 3) and 0.5mm (group 4). The restorations were cemented onto human molars with a self-adhesive resin cement. The specimens were loaded until fracture; the fracture resistance and mode of failure were recorded. The data were statistically analyzed with the one-way ANOVA followed by the Fisher׳s Exact test with Bonferroni׳s correction (p=0.05). The fracture resistance values of all the specimens exceeded the maximum physiological occlusal loads in molar regions. All the crowns showed cohesive microcracks of the zirconia core; only 1 crown with a thickness of 0.5mm was interested by a complete fracture. The occlusal thickness of CAD-CAM monolithic zirconia crowns did not influence either the fracture resistance and the mode of failure of the restorations; the occlusal thickness of CAD-CAM monolithic zirconia crowns can be reduced up to a lower bound of 0.5mm keeping a sufficient strength to withstand occlusal loads; CAD-CAM monolithic zirconia crowns showed sufficient fracture resistance to be used in molar regions, even in a thin configuration (0.5mm). Copyright © 2016 Elsevier Ltd. All rights reserved.

In Situ Formation of Polysulfonamide Supported Poly(ethylene glycol) Divinyl Ether Based Polymer Electrolyte toward Monolithic Sodium Ion Batteries.

PubMed

Zhang, Jianjun; Wen, Huijie; Yue, Liping; Chai, Jingchao; Ma, Jun; Hu, Pu; Ding, Guoliang; Wang, Qingfu; Liu, Zhihong; Cui, Guanglei; Chen, Liquan

2017-01-01

Sodium ion battery is one of the promising rechargeable batteries due to the low-cost and abundant sodium sources. In this work, a monolithic sodium ion battery based on a Na 3 V 2 (PO 4 ) 3 cathode, MoS 2 layered anode, and polyether-based polymer electrolyte is reported. In addition, a new kind of polysulfonamide-supported poly(ethylene glycol) divinyl ether based polymer electrolyte is also demonstrated for monolithic sodium ion battery via in situ preparation. The resultant polymer electrolyte exhibits relatively high ionic conductivity (1.2 mS cm -1 ) at ambient temperature, wide electrochemical window (4.7 V), and favorable mechanical strength (25 MPa). Moreover, such a monolithic Na 3 V 2 (PO 4 ) 3 /MoS 2 sodium ion battery using this polymer electrolyte delivers outstanding rate capability (up to 10 C) and superior cyclic stability (84%) after 1000 cycles at 0.5 C. What is more essential, such a polymer electrolyte based soft-package monolithic sodium ion cell can still power a red light emitting diode lamp and run finite times without suffering from any internal short-circuit failures, even in the case of a bended and wrinkled state. Considering these aspects, this work no doubt provides a new approach for the design of a high-performance polymer electrolyte toward monolithic sodium ion battery with exceptional rate capability and high safety. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Fabrication of CMC-g-PAM Superporous Polymer Monoliths via Eco-Friendly Pickering-MIPEs for Superior Adsorption of Methyl Violet and Methylene Blue.

PubMed

Wang, Feng; Zhu, Yongfeng; Wang, Wenbo; Zong, Li; Lu, Taotao; Wang, Aiqin

2017-01-01

A series of superporous carboxymethylcellulose- graft -poly(acrylamide)/palygorskite (CMC- g -PAM/Pal) polymer monoliths presenting interconnected pore structure and excellent adsorption properties were prepared by one-step free-radical grafting polymerization reaction of CMC and acrylamide (AM) in the oil-in-water (O/W) Pickering-medium internal phase emulsions (Pickering-MIPEs) composed of non-toxic edible oil as a dispersion phase and natural Pal nanorods as stabilizers. The effects of Pal dosage, AM dosage, and co-surfactant Tween-20 (T-20) on the pore structures of the monoliths were studied. It was revealed that the well-defined pores were formed when the dosages of Pal and T-20 are 9-14 and 3%, respectively. The porous monolith can rapidly adsorb 1,585 mg/g of methyl violet (MV) and 1,625 mg/g of methylene blue (MB). After the monolith was regenerated by adsorption-desorption process for five times, the adsorption capacities still reached 92.1% (for MV) and 93.5% (for MB) of the initial maximum adsorption capacities. The adsorption process was fitted with Langmuir adsorption isotherm model and pseudo-second-order adsorption kinetic model very well, which indicate that mono-layer chemical adsorption mainly contribute to the high-capacity adsorption for dyes. The superporous polymer monolith prepared from eco-friendly Pickering-MIPEs shows good adsorption capacity and fast adsorption rate, which is potential adsorbent for the decontamination of dye-containing wastewater.

Flexural strength and reliability of monolithic and trilayer ceramic structures obtained by the CAD-on technique.

PubMed

Basso, G R; Moraes, R R; Borba, M; Griggs, J A; Della Bona, A

2015-12-01

To evaluate the flexural strength, Weibull modulus, fracture toughness, and failure behavior of ceramic structures obtained by the CAD-on technique, testing the null hypothesis that trilayer structures show similar properties to monolithic structures. Bar-shaped (1.8mm×4mm×16mm) monolithic specimens of zirconia (IPS e.max ZirCAD - Ivoclar Vivadent) and trilayer specimens of zirconia/fusion ceramic/lithium dissilicate (IPS e.max ZirCAD/IPS e.max CAD Crystall./Connect/IPS e.max CAD, Ivoclar Vivadent) were fabricated (n=30). Specimens were tested in flexure in 37°C deionized water using a universal testing machine at a crosshead speed of 0.5mm/min. Failure loads were recorded, and the flexural strength values were calculated. Fractography principles were used to examine the fracture surfaces under optical and scanning electron microscopy. Data were statistically analyzed using Student's t-test and Weibull statistics (α=0.05). Monolithic and trilayer specimens showed similar mean flexural strengths, characteristic strengths, and Weibull moduli. Trilayer structures showed greater mean critical flaw and fracture toughness values than monolithic specimens (p<0.001). Most critical flaws in the trilayer groups were located on the Y-TZP surface subjected to tension and propagated catastrophically. Trilayer structures showed no flaw deflection at the interface. Considering the CAD-on technique, the trilayer structures showed greater fracture toughness than the monolithic zirconia specimens. Copyright © 2015 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Black holes, disks, and jets following binary mergers and stellar collapse: The narrow range of electromagnetic luminosities and accretion rates.

PubMed

Shapiro, Stuart L

2017-05-15

We have performed magnetohydrodynamic simulations in general relativity of binary neutron star and binary black hole-neutron star mergers, as well as the magnetorotational collapse of supermassive stars. In many cases the outcome is a spinnng black hole (BH) immersed in a magnetized disk, with a jet emanating from the poles of the BH. While their formation scenarios differ and their BH masses, as well as their disk masses, densities, and magnetic field strengths, vary by orders of magnitude, these features conspire to generate jet Poynting luminosities that all lie in the same, narrow range of ~10 52±1 erg s -1 . A similar result applies to their BH accretion rates upon jet launch, which is ~0.1-10 M ⊙ s -1 . We provide a simple model that explains these unanticipated findings. Interestingly, these luminosities reside in the same narrow range characterizing the observed luminosity distributions of over 400 short and long GRBs with distances inferred from spectroscopic redshifts or host galaxies. This result, together with the GRB lifetimes predicted by the model, supports the belief that a compact binary merger is the progenitor of an SGRB, while a massive, stellar magnetorotational collapse is the progenitor of an LGRB.

Black holes, disks, and jets following binary mergers and stellar collapse: The narrow range of electromagnetic luminosities and accretion rates

PubMed Central

Shapiro, Stuart L.

2018-01-01

We have performed magnetohydrodynamic simulations in general relativity of binary neutron star and binary black hole-neutron star mergers, as well as the magnetorotational collapse of supermassive stars. In many cases the outcome is a spinnng black hole (BH) immersed in a magnetized disk, with a jet emanating from the poles of the BH. While their formation scenarios differ and their BH masses, as well as their disk masses, densities, and magnetic field strengths, vary by orders of magnitude, these features conspire to generate jet Poynting luminosities that all lie in the same, narrow range of ~1052±1 erg s−1. A similar result applies to their BH accretion rates upon jet launch, which is ~0.1–10 M⊙ s−1. We provide a simple model that explains these unanticipated findings. Interestingly, these luminosities reside in the same narrow range characterizing the observed luminosity distributions of over 400 short and long GRBs with distances inferred from spectroscopic redshifts or host galaxies. This result, together with the GRB lifetimes predicted by the model, supports the belief that a compact binary merger is the progenitor of an SGRB, while a massive, stellar magnetorotational collapse is the progenitor of an LGRB. PMID:29881790

Influence de l'alteration physique sur les caracteristiques physico-chimiques de monolithes de sols contamines traites par stabilisation/solidification au ciment

NASA Astrophysics Data System (ADS)

Remillard, Jonathan

The concern of contaminated sites is affecting millions of property owner worldwide. As they pose a risk to the environment, human health or impair the value of buildings, remediation of contaminated sites has become an everyday issue. Stabilization/solidification (S/S) of contaminated soils with cement is a remediation technology that was developed to confine contaminants that cannot be degraded biologically, chemically or thermally by other technologies. Soils treated with S/S form a monolith that can be valorized on site. However, this practice is fairly uncommon in Quebec and this reluctance is partly due to the risks of degradation of the monoliths and the lack of knowledge relative to the long-term behavior of altered monoliths. The objective of this project was to simulate these degradations on cement-based monoliths of contaminated soils treated with S/S technology by causing physical alterations using different cycles of freeze/thawing and drying/wetting, and then to study the impact of these alterations on the mass losses, compressive strength, hydraulic conductivity, pH and leachability of five trace metals (Cd, Cr, Cu, Pb and Zn) used as contaminants. Various processes of S/S have been studied, either cement contents of 15 and 20%, then the presence of 5% by weight of calcium carbonate. For each S/S process formulated, the freeze/thaw cycles were much more effective in physically altering the monoliths. These alterations were mainly reflected by lower compressive strength, even more with lower cement contents. For their part, the drying/wetting cycles rather created a chemical change that lowered the pH of the monoliths. These chemical changes also affected the interpretation of leaching test results, especially for copper and zinc, since it was difficult to attribute effects to either physical or chemical alterations. The results showed that only chromium leached more clearly in response to physical alterations. All other elements studied were little affected, even though some samples were highly altered. This demonstrates that in some cases, damages may have little impact on long-term performance of the monoliths in terms of contaminant immobilization. However, integrating the study of long-term behaviors of monoliths in a process of formulation for contaminated soil treatment with S/S can become paramount, as seen for chromium in this present study. Keywords: stabilization / solidification, deterioration, alteration, leachability, contaminants.

Biasable, Balanced, Fundamental Submillimeter Monolithic Membrane Mixer

NASA Technical Reports Server (NTRS)

Siegel, Peter; Schlecht, Erich; Mehdi, Imran; Gill, John; Velebir, James; Tsang, Raymond; Dengler, Robert; Lin, Robert

2010-01-01

This device is a biasable, submillimeter-wave, balanced mixer fabricated using JPL s monolithic membrane process a simplified version of planar membrane technology. The primary target application is instrumentation used for analysis of atmospheric constituents, pressure, temperature, winds, and other physical and chemical properties of the atmospheres of planets and comets. Other applications include high-sensitivity gas detection and analysis. This innovation uses a balanced configuration of two diodes allowing the radio frequency (RF) signal and local oscillator (LO) inputs to be separated. This removes the need for external diplexers that are inherently narrowband, bulky, and require mechanical tuning to change frequency. Additionally, this mixer uses DC bias-ability to improve its performance and versatility. In order to solve problems relating to circuit size, the GaAs membrane process was created. As much of the circuitry as possible is fabricated on-chip, making the circuit monolithic. The remainder of the circuitry is precision-machined into a waveguide block that holds the GaAs circuit. The most critical alignments are performed using micron-scale semiconductor technology, enabling wide bandwidth and high operating frequencies. The balanced mixer gets superior performance with less than 2 mW of LO power. This can be provided by a simple two-stage multiplier chain following an amplifier at around 90 GHz. Further, the diodes are arranged so that they can be biased. Biasing pushes the diodes closer to their switching voltage, so that less LO power is required to switch the diodes on and off. In the photo, the diodes are at the right end of the circuit. The LO comes from the waveguide at the right into a reduced-height section containing the diodes. Because the diodes are in series to the LO signal, they are both turned on and off simultaneously once per LO cycle. Conversely, the RF signal is picked up from the RF waveguide by the probe at the left, and flows rightward to the diodes. Because the RF is in a quasi- TEM (suspended, microstrip-like) mode, it impinges on the diodes in an anti-parallel mode that does not couple to the waveguide mode. This isolates the LO and RF signals. This operation is similar to a cross-bar mixer used at low frequencies, except the RF signal enters through the back-short end of the waveguide rather than through the side. The RF probe also conveys the down-converted intermediate frequency (IF) signal out to an off-chip circuit board through a simple LC low-pass filter to the left as indicated. The bias is brought to the diodes through a bypass capacitor at the top.

Comparison of monolithic and microparticulate columns for reversed-phase liquid chromatography of tryptic digests of industrial enzymes in cleaning products.

PubMed

Beneito-Cambra, M; Herrero-Martínez, J M; Ramis-Ramos, G; Lindner, W; Lämmerhofer, M

2011-10-14

Enzymes of several classes used in the formulations of cleaning products were characterized by trypsin digestion followed by HPLC with UV detection. A polymeric monolithic column (ProSwift) was used to optimize the separation of both the intact enzymes and their tryptic digests. This column was adequate for the quality control of raw industrial enzyme concentrates. Then, monolithic and microparticulate columns were compared for peptide analysis. Under optimized conditions, the analysis of tryptic digests of enzymes of different classes commonly used in the formulation of cleaning products was carried out. Number of peaks, peak capacity and global resolution were obtained in order to evaluate the chromatographic performance of each column. Particulate shell-core C18 columns (Kinetex, 2.6 μm) showed the best performance, followed by a silica monolithic column (Chromolith RP-18e) and the conventional C18 packings (Gemini, 5 μm or 3 μm). A polymeric monolithic column (ProSwift) gave the worst performances. The proposed method was satisfactorily applied to the characterization of the enzymes present in spiked detergent bases and commercial cleaners. Copyright © 2011 Elsevier B.V. All rights reserved.

Behavior of micro-particles in monolith ceramic membrane filtration with pre-coagulation.

PubMed

Yonekawa, H; Tomita, Y; Watanabe, Y

2004-01-01

This paper is intended to clarify the characteristics unique to monolith ceramic membranes with pre-coagulation by referring to the behavior of micro-particles. Flow analysis and experiments have proved that monolith ceramic membranes show a unique flow pattern in the channels within the element, causing extremely rapid flocculation in the channel during dead-end filtration. It was assumed that charge-neutralized micro-particles concentrated near the membrane surface grow in size due to flocculation, and as a result, coarse micro-particles were taken up by the shearing force to flow out. As the dead end points of flow in all the channels are located near the end of the channels with higher filterability, most of the flocculated coarse particles are formed to a columnar cake intensively at the dead end point. Therefore cake layer forming on the membrane other than around the dead end point is alleviated. This behavior of particle flocculation and cake formation at the dead end point within the channels are unique characteristics of monolith ceramic membranes. This is why all monolith ceramic membrane water purification systems operating in Japan do not have pretreatment equipment for flocculation and sedimentation.

Computer-aided design comparisons of monolithic and hybrid MEM-tunable VCSELs

NASA Astrophysics Data System (ADS)

Ochoa, Edward M.; Nelson, Thomas R., Jr.; Blum-Spahn, Olga; Lott, James A.

2003-07-01

We report and use our micro-electro-mechanically tunable vertical cavity surface emitting laser (MEM-TVCSEL) computer-aided design methodology to investigate the resonant frequency design space for monolithic and hybrid MEM-TVCSELs. For various initial optical air gap thickness, we examine the sensitivity of monolithic or hybrid MEM-TVCSEL resonant frequency by simulating zero, two, and four percent variations in III-V material growth thickness. As expected, as initial optical airgap increases, tuning range decreases due to less coupling between the active region and the tuning mirror. However, each design has different resonant frequency sensitivity to variations in III-V growth parameters. In particular, since the monolithic design is comprised of III-V material, the shift in all growth thicknesses significantly shifts the resonant frequency response. However, for hybrid MEMTVCSELs, less shift results, since the lower reflector is an Au mirror with reflectivity independent of III-V growth variations. Finally, since the hybrid design is comprised of a MUMPS polysilicon mechanical actuator, pull-in voltage remains independent of the initial optical airgap between the tuning reflector and the III-V material. Conversely, as the initial airgap increases in the monolithic design, the pull-in voltage significantly increases.

Optimization and application of octadecyl-modified monolithic silica for solid-phase extraction of drugs in whole blood samples.

PubMed

Namera, Akira; Saito, Takeshi; Ota, Shigenori; Miyazaki, Shota; Oikawa, Hiroshi; Murata, Kazuhiro; Nagao, Masataka

2017-09-29

Monolithic silica in MonoSpin for solid-phase extraction of drugs from whole blood samples was developed to facilitate high-throughput analysis. Monolithic silica of various pore sizes and octadecyl contents were synthesized, and their effects on recovery rates were evaluated. The silica monolith M18-200 (20μm through-pore size, 10.4nm mesopore size, and 17.3% carbon content) achieved the best recovery of the target analytes in whole blood samples. The extraction proceeded with centrifugal force at 1000rpm for 2min, and the eluate was directly injected into the liquid chromatography-mass spectrometry system without any tedious steps such as evaporation of extraction solvents. Under the optimized condition, low detection limits of 0.5-2.0ngmL -1 and calibration ranges up to 1000ngmL -1 were obtained. The recoveries of the target drugs in the whole blood were 76-108% with relative standard deviation of less than 14.3%. These results indicate that the developed method based on monolithic silica is convenient, highly efficient, and applicable for detecting drugs in whole blood samples. Copyright © 2017 Elsevier B.V. All rights reserved.

CeO2-CuO/Cu2O/Cu monolithic catalysts with three-kind morphologies Cu2O layers for preferential CO oxidation

NASA Astrophysics Data System (ADS)

Jing, Guojuan; Zhang, Xuejiao; Zhang, Aiai; Li, Meng; Zeng, Shanghong; Xu, Changjin; Su, Haiquan

2018-03-01

The supports of copper slices with three-kind morphologies Cu2O layers were prepared by the hydrothermal method. The Cu2O layers are rod-like structure, three-dimensional reticular and porous morphology as well as flower-like morphology, respectively. The CeO2-CuO/Cu2O/Cu monolithic catalysts present porous and network structure or foam morphology after loading CeO2 and CuO. Cu and Ce elements are uniformly dispersed onto the support surface. It is found that the monolithic catalyst with flower-like Cu2O layer displays better low-temperature activity because of highly-dispersed CuO and high Olatt concentration. The monolithic catalysts with rod-like or reticular-morphology Cu2O layers present high-temperature activity due to larger CuO crystallite sizes and good synergistic effect at copper-ceria interfacial sites. The as-prepared CeO2-CuO/Cu2O/Cu monolithic catalysts show good performance in the CO-PROX reaction. The generation of Cu2O layers with three-kind morphologies is beneficial to the loading and dispersion of copper oxides and ceria.

Elevated-temperature fracture resistances of monolithic and composite ceramics using chevron-notched bend tests

NASA Technical Reports Server (NTRS)

Ghosh, Asish; Jenkins, Michael G.; Ferber, Mattison K.; Peussa, Jouko; Salem, Jonathan A.

1992-01-01

The quasi-static fracture behaviors of monolithic ceramics (SiC, Si3N4, MgAl2O4), self-reinforced monoliths (acicular grained Si3N4, acicular grained mullite), and ceramic matrix composites (SiC whisker/Al2O3 matrix, TiB2 particulate/SiC matrix, SiC fiber/CVI SiC matrix, Al2O3 fiber/CVI SiC matrix) were measured over the temperature range of 20 to 1400 C. The chevron notched, bend bar test geometry was essential for characterizing the elevated temperature fracture resistances of this wide range of quasi-brittle materials during stable crack growth. Fractography revealed the differences in the fracture behavior of the different materials at the various temperatures. The fracture resistances of the self-reinforced monoliths were comparable to those of the composites and the fracture mechanisms were found to be similar at room temperature. However at elevated temperatures the differences of the fracture behavior became apparent where the superior fracture resistance of the self-reinforced monoliths were attributed to the minor amounts of glassy, intergranular phases which were often more abundant in the composites and affected the fracture behavior when softened by elevated temperatures.

Comparison of Positively and Negatively Charged Achiral Co-Monomers Added to Cyclodextrin Monolith: Improved Chiral Separations in Capillary Electrochromatography

PubMed Central

Lu, Yang; Shamsi, Shahab A.

2014-01-01

Cyclodextrins (CDs) and their derivatives have been one of the most popular and successful chiral additives used in electrokinetic chromatography because of the presence of multiple chiral centers, which leads to multiple chiral interactions. However, there has been relatively less published work on the use of CDs as monolithic media for capillary electrochromatography (CEC). The goal of this study was to show how the addition of achiral co-monomer to a polymerizable CD such as glycidyl methacrylate β-cyclodextrin (GMA/β-CD) can affect the enantioselective separations in monolithic CEC. To achieve this goal, polymeric monoliths columns were prepared by co-polymerizing GMA/β-CD with cationic or anionic achiral co-monomers [(2-acrylamido-2-methyl-1-propanesulfonic acid (AMPS) and vinyl benzyltrimethyl-ammonium (VBTA)] in the presence of conventional crosslinker (ethylene dimethacrylate) and ternary porogen system including butanediol, propanol and water. A total of 34 negatively charged compounds, 30 positively charged compounds and 33 neutral compounds were screened to compare the enantioresolution capability on the GMA/β-CD, GMA/β-CD-VBTA and GMA/β-CD-AMPS monolithic columns. PMID:24108813

A facile and efficient single-step approach for the fabrication of vancomycin functionalized polymer-based monolith as chiral stationary phase for nano-liquid chromatography.

PubMed

Xu, Dongsheng; Shao, Huikai; Luo, Rongying; Wang, Qiqin; Sánchez-López, Elena; Fanali, Salvatore; Marina, Maria Luisa; Jiang, Zhengjin

2018-07-06

A facile single-step preparation strategy for fabricating vancomycin functionalized organic polymer-based monolith within 100μm fused-silica capillary was developed. The synthetic chiral functional monomer, i.e 2-isocyanatoethyl methacrylate (ICNEML) derivative of vancomycin, was co-polymerized with the cross-linker ethylene dimethacrylate (EDMA) in the presence of methanol and dimethyl sulfoxide as the selected porogens. The co-polymerization conditions were systematically optimized in order to obtain satisfactory column performance. Adequate permeability, stability and column morphology were observed for the optimized poly(ICNEML-vancomycin-co-EDMA) monolith. A series of chiral drugs were evaluated on the monolith in either polar organic-phase or reversed-phase modes. After the optimization of separation conditions, baseline or partial enantioseparation were obtained for series of drugs including thalidomide, colchicine, carteolol, salbutamol, clenbuterol and several other β-blockers. The proposed single-step approach not only resulted in a vancomycin functionalized organic polymer-based monolith with acceptable performance, but also significantly simplified the preparation procedure by reducing time and labor. Copyright © 2018 Elsevier B.V. All rights reserved.

Multiwalled carbon nanotube monoliths prepared by spark plasma sintering (SPS) and their mechanical properties.

PubMed

Uo, Motohiro; Hasegawa, Tomoka; Akasaka, Tsukasa; Tanaka, Isao; Munekane, Fuminori; Omori, Mamoru; Kimura, Hisamichi; Nakatomi, Reiko; Soga, Kohei; Kogo, Yasuo; Watari, Fumio

2009-01-01

Three types of multiwalled carbon nanotube (MWCNT) monoliths without any binders were obtained by spark plasma sintering (SPS) treatment at 2000 degrees C under 80 MPa sintering pressure. Three MWCNTs with different diameters: thin (slashed circle20-30 nm, CNT Co., Ltd., Korea), thick (slashed circle100 nm, Nano Carbon Technologies Co., Ltd., Japan) and spherical thin (slashed circle20-30 nm, granulated diameter = 1-3 microm, Shimizu Corporation, Japan) were employed for SPS. SEM observation confirmed that these materials maintained the nanosized tube microstructure of raw CNT powder after SPS treatment. The densest monolith was prepared with the spherical MWCNTs. The mechanical properties of this material were estimated by the dynamic hardness test. The elastic modulus of the monolith did not depend on the difference of MWCNTs, but the hardness of spherical MWCNTs was higher than that of thick MWCNTs. The high density and hardness of the spherical MWCNTs were caused by the high packing density during the SPS process because of its spherical granulation. Thus, the spherical MWCNTs were most useful for the MWCNT monolith preparation with the SPS process and its application as a bone substitute material and a bone tissue engineering scaffold material was suggested.

Shear bond strength of indirect composite material to monolithic zirconia.

PubMed

Sari, Fatih; Secilmis, Asli; Simsek, Irfan; Ozsevik, Semih

2016-08-01

This study aimed to evaluate the effect of surface treatments on bond strength of indirect composite material (Tescera Indirect Composite System) to monolithic zirconia (inCoris TZI). Partially stabilized monolithic zirconia blocks were cut into with 2.0 mm thickness. Sintered zirconia specimens were divided into different surface treatment groups: no treatment (control), sandblasting, glaze layer & hydrofluoric acid application, and sandblasting + glaze layer & hydrofluoric acid application. The indirect composite material was applied to the surface of the monolithic zirconia specimens. Shear bond strength value of each specimen was evaluated after thermocycling. The fractured surface of each specimen was examined with a stereomicroscope and a scanning electron microscope to assess the failure types. The data were analyzed using one-way analysis of variance (ANOVA) and Tukey LSD tests (α=.05). Bond strength was significantly lower in untreated specimens than in sandblasted specimens (P<.05). No difference between the glaze layer and hydrofluoric acid application treated groups were observed. However, bond strength for these groups were significantly higher as compared with the other two groups (P<.05). Combined use of glaze layer & hydrofluoric acid application and silanization are reliable for strong and durable bonding between indirect composite material and monolithic zirconia.

Magnetic Fields and Multiple Protostar Formation

NASA Astrophysics Data System (ADS)

Boss, A. P.

2001-12-01

Recent observations of star-forming regions suggest that binary and multiple young stars are the rule rather than the exception, and implicate fragmentation as the likely mechanism for their formation. Most numerical hydrodynamical calculations of fragmentation have neglected the possibly deleterious effects of magnetic fields, in spite of ample evidence for the importance of magnetic support of pre-collapse clouds. We present here the first numerical hydrodynamical survey of the full effects of magnetic fields on the collapse and fragmentation of dense cloud cores. The models are calculated with a three dimensional, finite differences code which solves the equations of hydrodynamics, gravitation, and radiative transfer in the Eddington and diffusion approximations. Magnetic field effects are included through two simple approximations: magnetic pressure is added to the gas pressure, and magnetic tension is approximated by gravity dilution once collapse is well underway. Ambipolar diffusion of the magnetic field leading to cloud collapse is treated approximately as well. Models are calculated for a variety of initial cloud density profiles, shapes, and rotation rates. We find that in spite of the inclusion of magnetic field effects, dense cloud cores are capable of fragmenting into binary and multiple protostar systems. Initially prolate clouds tend to fragment into binary protostars, while initially oblate clouds tend to fragment into multiple protostar systems containing a small number (of order four) of fragments. The latter are likely to be subject to rapid orbital evolution, with close encounters possibly leading to the ejection of fragments. Contrary to expectation, magnetic tension effects appear to enhance fragmentation, allowing lower mass fragments to form than would otherwise be possible, because magnetic tension helps to prevent a central density singularity from forming and producing a dominant single object. Magnetically-supported dense cloud cores thus seem to be capable of collapsing and fragmenting into sufficient numbers of binary and multiple protostar systems to be compatible with observations of the relative rarity of single protostars. This work was partially supported by NSF grants AST-9983530 and MRI-9976645.

Collapse and Fragmentation of Molecular Cloud Cores. VII. Magnetic Fields and Multiple Protostar Formation

NASA Astrophysics Data System (ADS)

Boss, Alan P.

2002-04-01

Recent observations of star-forming regions suggest that binary and multiple young stars are the rule rather than the exception and implicate fragmentation as the likely mechanism for their formation. Most numerical hydrodynamic calculations of fragmentation have neglected the possibly deleterious effects of magnetic fields, despite ample evidence for the importance of magnetic support of precollapse clouds. We present here the first numerical hydrodynamic survey of the collapse and fragmentation of initially magnetically supported clouds that takes into account several magnetic field effects in an approximate manner. The models are calculated with a three-dimensional, finite differences code that solves the equations of hydrodynamics, gravitation, and radiative transfer in the Eddington and diffusion approximations. Magnetic field effects are included through two simple approximations: magnetic pressure is added to the gas pressure, and magnetic tension is approximated by gravity dilution once collapse is well underway. Ambipolar diffusion of the magnetic field leading to cloud collapse is treated approximately as well. Models are calculated for a variety of initial cloud density profiles, shapes, and rotation rates. We find that in spite of the inclusion of magnetic field effects, dense cloud cores are capable of fragmenting into binary and multiple protostar systems. Initially prolate clouds tend to fragment into binary protostars, while initially oblate clouds tend to fragment into multiple protostar systems containing a small number (of the order of 4) of fragments. The latter are likely to be subject to rapid orbital evolution, with close encounters possibly leading to the ejection of fragments. Contrary to expectation, magnetic tension effects appear to enhance fragmentation, allowing lower mass fragments to form than would otherwise be possible, because magnetic tension helps to prevent a central density singularity from forming and producing a dominant single object. Magnetically supported dense cloud cores thus seem to be capable of collapsing and fragmenting into sufficient numbers of binary and multiple protostar systems to be compatible with observations of the relative rarity of single protostars.

Graphene-Based Standalone Solar Energy Converter for Water Desalination and Purification.

PubMed

Yang, Yang; Zhao, Ruiqi; Zhang, Tengfei; Zhao, Kai; Xiao, Peishuang; Ma, Yanfeng; Ajayan, Pulickel M; Shi, Gaoquan; Chen, Yongsheng

2018-01-23

Harvesting solar energy for desalination and sewage treatment has been considered as a promising solution to produce clean water. However, state-of-the-art technologies often require optical concentrators and complicated systems with multiple components, leading to poor efficiency and high cost. Here, we demonstrate an extremely simple and standalone solar energy converter consisting of only an as-prepared 3D cross-linked honeycomb graphene foam material without any other supporting components. This simple all-in-one material can act as an ideal solar thermal converter capable of capturing and converting sunlight into heat, which in turn can distill water from various water sources into steam and produce purified water under ambient conditions and low solar flux with very high efficiency. High specific water production rate of 2.6 kg h -1 m -2 g -1 was achieved with near ∼87% under 1 sun intensity and >80% efficiency even under ambient sunlight (<1 sun). This scalable sheet-like material was used to obtain pure drinkable water from both seawater and sewage water under ambient conditions. Our results demonstrate a competent monolithic material platform providing a paradigm change in water purification by using a simple, point of use, reusable, and low-cost solar thermal water purification system for a variety of environmental conditions.

Cosmological Perturbation Theory and the Spherical Collapse model - I. Gaussian initial conditions

NASA Astrophysics Data System (ADS)

Fosalba, Pablo; Gaztanaga, Enrique

1998-12-01

We present a simple and intuitive approximation for solving the perturbation theory (PT) of small cosmic fluctuations. We consider only the spherically symmetric or monopole contribution to the PT integrals, which yields the exact result for tree-graphs (i.e. at leading order). We find that the non-linear evolution in Lagrangian space is then given by a simple local transformation over the initial conditions, although it is not local in Euler space. This transformation is found to be described by the spherical collapse (SC) dynamics, as it is the exact solution in the shearless (and therefore local) approximation in Lagrangian space. Taking advantage of this property, it is straightforward to derive the one-point cumulants, xi_J, for both the unsmoothed and smoothed density fields to arbitrary order in the perturbative regime. To leading-order this reproduces, and provides us with a simple explanation for, the exact results obtained by Bernardeau. We then show that the SC model leads to accurate estimates for the next corrective terms when compared with the results derived in the exact perturbation theory making use of the loop calculations. The agreement is within a few per cent for the hierarchical ratios S_J=xi_J/xi^J-1_2. We compare our analytic results with N-body simulations, which turn out to be in very good agreement up to scales where sigma~1. A similar treatment is presented to estimate higher order corrections in the Zel'dovich approximation. These results represent a powerful and readily usable tool to produce analytical predictions that describe the gravitational clustering of large-scale structure in the weakly non-linear regime.

Amine-impregnated silica monolith with a hierarchical pore structure: enhancement of CO2 capture capacity.

PubMed

Chen, Chao; Yang, Seung-Tae; Ahn, Wha-Seung; Ryoo, Ryong

2009-06-28

A polyethylenimine-impregnated hierarchical silica monolith exhibited significantly higher CO(2) capturing capacity than other silica-supported amine sorbents, and produced a reversible and durable sorption performance.

The development of structures in analogue and natural debris avalanches

NASA Astrophysics Data System (ADS)

Paguican, Engielle Mae; van Wyk de Vries, Benjamin; Mahar Francisco Lagmay, Alfredo; Grosse, Pablo

2010-05-01

All types of rockslide-debris avalanches present a plethora of internal structures that are also well observed on the surface. Many of these are seen as faults and folds that can be used to determine deformation history and kinematics. We present two sets of simple and well-constrained experiments of reduced basal friction laboratory rockslides, equivalent to a highly deformed simple shear layer, with plug-flow. These follow the original ramp-slide work of Shea and van Wyk de Vries (Geosphere, 2008). The experiments used a curved ramp where materials accelerate until reaching a gently-sloped depositional surface and a constantly inclined ramp with a more regular slope and longer slides. A detailed description of deposit structures, their sequential formation and morphology is then used to investigate the transport type and deformation chronology from slide initiation to runout stopping of avalanches. Results using a curved ramp show accumulation and thickening at where the slope decreases. The thickened mass then further remobilises and advances by secondary collapse of the mass. Such a stop-start process may be important in many mountainous avalanches where there are rapid changes in slope. The constantly inclined ramp shows shearing and extensional structures at the levees and a set of compression and extension structures in the middle. We noted that frontal accumulation during flow occurs as materials at the front move slower relative to those in the medial and proximal zones. This also leads to secondary frontal collapse, and helps to maintain a thicker mass that can flow further. Descriptions and analyses of these structures are then applied to the kinematics and dynamics of natural examples. We study the 2006 Guinsaugon Rockslide event in the Philippines and find that frontal accumulation and secondary avalanching had also occurred and were important in determining the distribution and runout of the mass. Frontal bulking and collapse may also have occurred at the Tacna Avalanche, Peru and the Pajonales-Aracar event in Argentina.

Methods for preparation of three-dimensional bodies

DOEpatents

Mulligan, Anthony C.; Rigali, Mark J.; Sutaria, Manish P.; Artz, Gregory J.; Gafner, Felix H.; Vaidyanathan, K. Ranji

2004-09-28

Processes for mechanically fabricating two and three-dimensional fibrous monolith composites include preparing a fibrous monolith filament from a core composition of a first powder material and a boundary material of a second powder material. The filament includes a first portion of the core composition surrounded by a second portion of the boundary composition. One or more filaments are extruded through a mechanically-controlled deposition nozzle onto a working surface to create a fibrous monolith composite object. The objects may be formed directly from computer models and have complex geometries.

Methods for preparation of three-dimensional bodies

DOEpatents

Mulligan, Anthony C [Tucson, AZ; Rigali, Mark J [Carlsbad, NM; Sutaria, Manish P [Malden, MA; Artz, Gregory J [Tucson, AZ; Gafner, Felix H [Tucson, AZ; Vaidyanathan, K Ranji [Tucson, AZ

2008-06-17

Processes for mechanically fabricating two and three-dimensional fibrous monolith composites include preparing a fibrous monolith filament from a core composition of a first powder material and a boundary material of a second powder material. The filament includes a first portion of the core composition surrounded by a second portion of the boundary composition. One or more filaments are extruded through a mechanically-controlled deposition nozzle onto a working surface to create a fibrous monolith composite object. The objects may be formed directly from computer models and have complex geometries.

GaAs circuits for monolithic optical controller

NASA Technical Reports Server (NTRS)

Gustafson, G.; Bendett, M.; Carney, J.; Mactaggart, R.; Palmquist, S.

1988-01-01

GaAs circuits for use in a fully monolithic 1 Gb/s optical controller have been developed and tested. The circuits include photodetectors, transimpedance amplifiers and 1:16 demultiplexers that can directly control the phase of MMIC phase shifters. The entire chip contains approximately 300 self-aligned gate E/D-mode MESFETs. The MESFETs have one micron-wide gate and the E-mode FETs typically have transconductance of 200 ms/mm. Results of simulations and tests are reported. Also, the design and layout of the fully monolithic chip is discussed.

Hierarchical collapse of regular islands via dissipation

NASA Astrophysics Data System (ADS)

Jousseph, C. A. C.; Abdulack, S. A.; Manchein, C.; Beims, M. W.

2018-03-01

In this work we investigate how regular islands localized in a mixed phase-space of generic area-preserving Hamiltonian systems are affected by a small amount of dissipation. Mainly we search for a universality (hierarchy) in the convergence of higher-order resonances and their periods when dissipation increases. One very simple scenario is already known: when subjected to small dissipation, stable periodic points become sinks attracting almost all the surrounding orbits, destroying all invariant curves which divide the phase-space in chaotic and regular domains. However, performing numerical experiments with the paradigmatic Chirikov-Taylor standard mapping we show that this presumably simple scenario can be rather complicated. The first, not trivial, scenario is what happens to chaotic trajectories, since they can be attracted by the sinks or by chaotic attractors, in cases when they exist. We show that this depends very much on how basins of attraction are formed as dissipation increases. In addition, we demonstrate that higher-order resonances are usually first affected by small dissipation when compared to lower-order resonances from the conservative case. Nevertheless, this is not a generic behaviour. We show that a local hierarchical collapse of resonances, as dissipation increases, is related to the area of the islands from the conservative case surrounding the periodic orbits. All observed resonance destructions occur via the bifurcation phenomena and are quantified here by determining the largest finite-time Lyapunov exponent.

A child with a difficult airway: what do I do next?

PubMed

Engelhardt, Thomas; Weiss, Markus

2012-06-01

Difficulties in pediatric airway management are common and continue to result in significant morbidity and mortality. This review reports on current concepts in approaching a child with a difficult airway. Routine airway management in healthy children with normal airways is simple in experienced hands. Mask ventilation (oxygenation) is always possible and tracheal intubation normally simple. However, transient hypoxia is common in these children usually due to unexpected anatomical and functional airway problems or failure to ventilate during rapid sequence induction. Anatomical airway problems (upper airway collapse and adenoid hypertrophy) and functional airway problems (laryngospasm, bronchospasm, insufficient depth of anesthesia and muscle rigidity, gastric hyperinflation, and alveolar collapse) require urgent recognition and treatment algorithms due to insufficient oxygen reserves. Early muscle paralysis and epinephrine administration aids resolution of these functional airway obstructions. Children with an 'impaired' normal (foreign body, allergy, and inflammation) or an expected difficult (scars, tumors, and congenital) airway require careful planning and expertise. Training in the recognition and management of these different situations as well as a suitably equipped anesthesia workstation and trained personnel are essential. The healthy child with an unexpected airway problem requires clear strategies. The 'impaired' normal pediatric airway may be handled by anesthetists experienced with children, whereas the expected difficult pediatric airway requires dedicated pediatric anesthesia specialist care and should only be managed in specialized centers.

Relationships between self-diffusivity, packing fraction, and excess entropy in simple bulk and confined fluids.

PubMed

Mittal, Jeetain; Errington, Jeffrey R; Truskett, Thomas M

2007-08-30

Static measures such as density and entropy, which are intimately connected to structure, have featured prominently in modern thinking about the dynamics of the liquid state. Here, we explore the connections between self-diffusivity, density, and excess entropy for two of the most widely used model "simple" liquids, the equilibrium Lennard-Jones and square-well fluids, in both bulk and confined environments. We find that the self-diffusivity data of the Lennard-Jones fluid can be approximately collapsed onto a single curve (i) versus effective packing fraction and (ii) in appropriately reduced form versus excess entropy, as suggested by two well-known scaling laws. Similar data collapse does not occur for the square-well fluid, a fact that can be understood on the basis of the nontrivial effects that temperature has on its static structure. Nonetheless, we show that the implications of confinement for the self-diffusivity of both of these model fluids, over a broad range of equilibrium conditions, can be predicted on the basis of knowledge of the bulk fluid behavior and either the effective packing fraction or the excess entropy of the confined fluid. Excess entropy is perhaps the most preferable route due to its superior predictive ability and because it is a standard, unambiguous thermodynamic quantity that can be readily predicted via classical density functional theories of inhomogeneous fluids.

The growth of aspherical structure in the universe - Is the Local Supercluster an unusual system

NASA Technical Reports Server (NTRS)

White, S. D. M.; Silk, J.

1979-01-01

The growth and subsequent collapse of homogeneous ellipsoidal perturbations in a uniform expanding background is considered as a simple model for the formation of large-scale aspherical structures in the observed universe. Numerical calculations of the evolution of such perturbations turn out to be well described by an approximate analytic solution of the equations of motion, and simple relationships are found between the initial shape of a perturbation and its shape and kinematic properties at the time of collapse. Perturbations do not change their shape significantly until they reach a density contrast of order unity. As a result, structures with the kinematic properties of the Local Supercluster should form much more commonly in a low-density universe than in a flat universe. The homogeneity of the local Hubble flow, the motion of the Milky Way with respect to the microwave background, and the flattening of the Local Supercluster can be successfully accounted for by these models, provided that the initial perturbation is sufficiently flattened. Viable models are obtained only if the ratio of the lengths of the two smaller axes of the initial perturbation is at least 3:1 in an Einstein-de Sitter universe or at least 1.8:1 in a universe for which the density parameter (Omega) is of order 0.1, when the protocluster pancakes.

How tall can gelatin towers be? An introduction to elasticity and buckling

NASA Astrophysics Data System (ADS)

Taberlet, Nicolas; Ferrand, Jérémy; Camus, Élise; Lachaud, Léa; Plihon, Nicolas

2017-12-01

The stability of elastic towers is studied through simple hands-on experiments. Using gelatin-based stackable bricks, one can investigate the maximum height a simple structure can reach before collapsing. We show through experiments and by using the classical linear elastic theory that the main limitation to the height of such towers is the buckling of the elastic structures under their own weight. Moreover, the design and architecture of the towers can be optimized to greatly improve their resistance to self-buckling. To this aim, the maximum height of hollow and tapered towers is investigated. The experimental and theoretical developments presented in this paper can help students grasp the fundamental concepts in elasticity and mechanical stability.

Monolithic poly(1,2-bis(p-vinylphenyl)ethane) capillary columns for simultaneous separation of low- and high-molecular-weight compounds.

PubMed

Greiderer, Andreas; Ligon, S Clark; Huck, Christian W; Bonn, Günther K

2009-08-01

Monolithic poly(1,2-bis(p-vinylphenyl)ethane (BVPE)) capillary columns were prepared by thermally initiated free radical polymerisation of 1,2-bis(p-vinylphenyl)ethane in the presence of inert diluents (porogens) and alpha,alpha'-azoisobutyronitrile (AIBN) as initiator. Polymerisations were accomplished in 200 microm ID fused silica capillaries at 65 degrees C and for 60 min. Mercury intrusion porosimetry measurements of the polymeric RP support showed a broad bimodal pore-size-distribution of mesopores and small macropores in the range of 5-400 nm and flow-channels in the mum range. N(2)-adsorption (BET) analysis resulted in a tremendous enhancement of surface area (101 m(2)/g) of BVPE stationary phases compared to typical organic monoliths (approximately 20 m(2)/g), indicating the presence of a considerable amount of mesopores. Consequently, the adequate proportion of both meso- and (small) macropores allowed the rapid and high-resolution separation of low-molecular-weight compounds as well as biomolecules on the same monolithic support. At the same time, the high fraction of flow-channels provided enhanced column permeability. The chromatographic performance of poly(1,2-bis(p-vinylphenyl)ethane) capillary columns for the separation of biomolecules (proteins, oligonucleotides) and small molecules (alkyl benzenes, phenols, phenons) are demonstrated in this article. Additionally, pressure drop versus flow rate measurements of novel poly(1,2-bis(p-vinylphenyl)ethane) capillary columns confirmed high mechanical robustness, low swelling in organic solvents and high permeability. Due to the simplicity of monolith fabrication, comprehensive studies of the retention and separation behaviour of monolithic BVPE columns resulted in high run-to-run and batch-to-batch reproducibilities. All these attributes prove the excellent applicability of monolithic poly(1,2-bis(p-vinylphenyl)ethane) capillary columns for micro-HPLC towards a huge range of analytes of different chemistries and molecular sizes.

A sandpile model of grain blocking and consequences for sediment dynamics in step-pool streams

NASA Astrophysics Data System (ADS)

Molnar, P.

2012-04-01

Coarse grains (cobbles to boulders) are set in motion in steep mountain streams by floods with sufficient energy to erode the particles locally and transport them downstream. During transport, grains are often blocked and form width-spannings structures called steps, separated by pools. The step-pool system is a transient, self-organizing and self-sustaining structure. The temporary storage of sediment in steps and the release of that sediment in avalanche-like pulses when steps collapse, leads to a complex nonlinear threshold-driven dynamics in sediment transport which has been observed in laboratory experiments (e.g., Zimmermann et al., 2010) and in the field (e.g., Turowski et al., 2011). The basic question in this paper is if the emergent statistical properties of sediment transport in step-pool systems may be linked to the transient state of the bed, i.e. sediment storage and morphology, and to the dynamics in sediment input. The hypothesis is that this state, in which sediment transporting events due to the collapse and rebuilding of steps of all sizes occur, is analogous to a critical state in self-organized open dissipative dynamical systems (Bak et al., 1988). To exlore the process of self-organization, a cellular automaton sandpile model is used to simulate the processes of grain blocking and hydraulically-driven step collapse in a 1-d channel. Particles are injected at the top of the channel and are allowed to travel downstream based on various local threshold rules, with the travel distance drawn from a chosen probability distribution. In sandpile modelling this is a simple 1-d limited non-local model, however it has been shown to have nontrivial dynamical behaviour (Kadanoff et al., 1989), and it captures the essence of stochastic sediment transport in step-pool systems. The numerical simulations are used to illustrate the differences between input and output sediment transport rates, mainly focussing on the magnification of intermittency and variability in the system response by the processes of grain blocking and step collapse. The temporal correlation in input and output rates and the number of grains stored in the system at any given time are quantified by spectral analysis and statistics of long-range dependence. Although the model is only conceptually conceived to represent the real processes of step formation and collapse, connections will be made between the modelling results and some field and laboratory data on step-pool systems. The main focus in the discussion will be to demonstrate how even in such a simple model the processes of grain blocking and step collapse may impact the sediment transport rates to the point that certain changes in input are not visible anymore, along the lines of "shredding the signals" proposed by Jerolmack and Paola (2010). The consequences are that the notions of stability and equilibrium, the attribution of cause and effect, and the timescales of process and form in step-pool systems, and perhaps in many other fluvial systems, may have very limited applicability.

Monolithic three-dimensional electrochemical energy storage system on aerogel or nanotube scaffold

DOEpatents

Farmer, Joseph C; Stadermann, Michael

2013-11-12

A monolithic three-dimensional electrochemical energy storage system is provided on an aerogel or nanotube scaffold. An anode, separator, cathode, and cathodic current collector are deposited on the aerogel or nanotube scaffold.

Monolithic three-dimensional electrochemical energy storage system on aerogel or nanotube scaffold

DOEpatents

Farmer, Joseph Collin; Stadermann, Michael

2014-07-15

A monolithic three-dimensional electrochemical energy storage system is provided on an aerogel or nanotube scaffold. An anode, separator, cathode, and cathodic current collector are deposited on the aerogel or nanotube scaffold.

Embedded-monolith armor

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

McElfresh, Michael W.; Groves, Scott E; Moffet, Mitchell L.

2016-07-19

A lightweight armor system utilizing a face section having a multiplicity of monoliths embedded in a matrix supported on low density foam. The face section is supported with a strong stiff backing plate. The backing plate is mounted on a spall plate.

Development of monolithic nuclear fuels for RERTR by hot isostatic pressing

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

Jue, J.-F.; Park, Blair; Chapple, Michael

2008-07-15

The RERTR Program (Reduced Enrichment for Research and Test Reactors) is developing advanced nuclear fuels for high power test reactors. Monolithic fuel design provides a higher uranium loading than that of the traditional dispersion fuel design. In order to bond monolithic fuel meat to aluminum cladding, several bonding methods such as roll bonding, friction stir bonding and hot isostatic pressing, have been explored. Hot isostatic pressing is a promising process for low cost, batch fabrication of monolithic RERTR fuel plates. The progress on the development of this process at the Idaho National Laboratory will be presented. Due to the relativelymore » high processing temperature used, the reaction between fuel meat and aluminum cladding to form brittle intermetallic phases may be a concern. The effect of processing temperature and time on the fuel/cladding reaction will be addressed. The influence of chemical composition on the reaction will also be discussed. (author)« less

Monolithic optoelectronic integrated broadband optical receiver with graphene photodetectors

NASA Astrophysics Data System (ADS)

Cheng, Chuantong; Huang, Beiju; Mao, Xurui; Zhang, Zanyun; Zhang, Zan; Geng, Zhaoxin; Xue, Ping; Chen, Hongda

2017-07-01

Optical receivers with potentially high operation bandwidth and low cost have received considerable interest due to rapidly growing data traffic and potential Tb/s optical interconnect requirements. Experimental realization of 65 GHz optical signal detection and 262 GHz intrinsic operation speed reveals the significance role of graphene photodetectors (PDs) in optical interconnect domains. In this work, a novel complementary metal oxide semiconductor post-backend process has been developed for integrating graphene PDs onto silicon integrated circuit chips. A prototype monolithic optoelectronic integrated optical receiver has been successfully demonstrated for the first time. Moreover, this is a firstly reported broadband optical receiver benefiting from natural broadband light absorption features of graphene material. This work is a perfect exhibition of the concept of monolithic optoelectronic integration and will pave way to monolithically integrated graphene optoelectronic devices with silicon ICs for three-dimensional optoelectronic integrated circuit chips.

Monolithic integration of GaN-based light-emitting diodes and metal-oxide-semiconductor field-effect transistors.

PubMed

Lee, Ya-Ju; Yang, Zu-Po; Chen, Pin-Guang; Hsieh, Yung-An; Yao, Yung-Chi; Liao, Ming-Han; Lee, Min-Hung; Wang, Mei-Tan; Hwang, Jung-Min

2014-10-20

In this study, we report a novel monolithically integrated GaN-based light-emitting diode (LED) with metal-oxide-semiconductor field-effect transistor (MOSFET). Without additionally introducing complicated epitaxial structures for transistors, the MOSFET is directly fabricated on the exposed n-type GaN layer of the LED after dry etching, and serially connected to the LED through standard semiconductor-manufacturing technologies. Such monolithically integrated LED/MOSFET device is able to circumvent undesirable issues that might be faced by other kinds of integration schemes by growing a transistor on an LED or vice versa. For the performances of resulting device, our monolithically integrated LED/MOSFET device exhibits good characteristics in the modulation of gate voltage and good capability of driving injected current, which are essential for the important applications such as smart lighting, interconnection, and optical communication.

Monolithic optical phased-array transceiver in a standard SOI CMOS process.

PubMed

Abediasl, Hooman; Hashemi, Hossein

2015-03-09

Monolithic microwave phased arrays are turning mainstream in automotive radars and high-speed wireless communications fulfilling Gordon Moores 1965 prophecy to this effect. Optical phased arrays enable imaging, lidar, display, sensing, and holography. Advancements in fabrication technology has led to monolithic nanophotonic phased arrays, albeit without independent phase and amplitude control ability, integration with electronic circuitry, or including receive and transmit functions. We report the first monolithic optical phased array transceiver with independent control of amplitude and phase for each element using electronic circuitry that is tightly integrated with the nanophotonic components on one substrate using a commercial foundry CMOS SOI process. The 8 × 8 phased array chip includes thermo-optical tunable phase shifters and attenuators, nano-photonic antennas, and dedicated control electronics realized using CMOS transistors. The complex chip includes over 300 distinct optical components and over 74,000 distinct electrical components achieving the highest level of integration for any electronic-photonic system.

A Possible Astronomically Aligned Monolith at Gardom's Edge

NASA Astrophysics Data System (ADS)

Brown, Daniel; Alder, Andy; Bemand, Elizabeth

2015-05-01

A unique triangular shaped monolith located within the Peak District National Park at Gardom's Edge could be intentionally astronomically aligned. It is set within a landscape rich in late Neolithic and Bronze Age remains. We show that the stone is most likely in its original orientation owing to its clear signs of erosion and associated to the time period of the late Neolithic. It is tilted towards south and its north side slopes at an angle equal to the maximum altitude of the Sun at mid-summer. This alignment emphasizes the changing declinations of the Sun during the seasons as well as giving an indication of mid-summers day. This functionality is achieved by an impressive display of light and shadow on the north facing side of the monolith. Together with other monuments in the close vicinity the monolith would have represented an ideal marker or social arena for seasonal gatherings for the otherwise dispersed small communities.

Deposition of zeolite nanoparticles onto porous silica monolith

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

Gackowski, Mariusz; Bielanska, Elzbieta; Szczepanowicz, Krzysztof

2016-06-01

A facile and effective method of deposition of MFl zeolite nanoparticles (nanocrystals) onto macro-/mesoporous silica monolith was proposed. The electrostatic interaction between those two materials was induces by adsorption of cationic polyelectrolytes. That can be realized either by adsorption of polyelectrolyte onto silica monolith or on zeolite nanocrystals. The effect of time, concentration of zeolite nanocrystals, type of polyelectrolyte, and ultrasound treatment is scrutinized. Adsorption of polyelectrolyte onto silica monolith with subsequent deposition of nanocrystals resulted in a monolayer coverage assessed with SEM images. Infrared spectroscopy was applied as a useful method to determine the deposition effectiveness of zeolite nanocrystalsmore » onto silica. Modification of nanocrystals with polyelectrolyte resulted in a multilayer coverage due to agglomeration of particles. On the other hand, the excess of polyelectrolyte in the system resulted in a low coverage due to competition between polyelectrolyte and modified nanocrystals.« less

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

Wei, Chan Yi, E-mail: vicchanyiwei@hotmail.com; Ongkudon, Clarence M., E-mail: clarence@ums.edu.my; Kansil, Tamar, E-mail: tamarkansil87@gmail.com

Modern day synthesis protocols of methacrylate monolithic polymer adsorbent are based on existing polymerization blueprint without a thorough understanding of the dynamics of pore structure and formation. This has resulted in unproductiveness of polymer adsorbent consequently affecting purity and recovery of final product, productivity, retention time and cost effectiveness of the whole process. The problems magnified in monolith scaling-up where internal heat buildup resulting from external heating and high exothermic polymerization reaction was reflected in cracking of the adsorbent. We believe that through careful and precise control of the polymerization kinetics and parameters, it is possible to prepare macroporous methacrylatemore » monolithic adsorbents with controlled pore structures despite being carried out in an unstirred mould. This research involved the study of the effect of scaling-up on pore morphology of monolith, in other words, porous polymethacrylate adsorbents that were prepared via bulk free radical polymerization process by imaging the porous morphology of polymethacrylate with scanning electron microscope.« less

Evaluation of the capability of local helioseismology to discern between monolithic and spaghetti sunspot models

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

Felipe, T.; Crouch, A. D.; Birch, A. C., E-mail: tobias@nwra.com

2014-06-20

The helioseismic properties of the wave scattering generated by monolithic and spaghetti sunspots are analyzed by means of numerical simulations. In these computations, an incident f- or p {sub 1}-mode travels through the sunspot model, which produces absorption and phase shift of the waves. The scattering is studied by inspecting the wavefield, computing travel-time shifts, and performing Fourier-Hankel analysis. The comparison between the results obtained for both sunspot models reveals that the differences in the absorption coefficient can be detected above noise level. The spaghetti model produces a steep increase of the phase shift with the degree of the modemore » at short wavelengths, while mode mixing is more efficient for the monolithic model. These results provide a clue for what to look for in solar observations to discern the constitution of sunspots between the proposed monolithic and spaghetti models.« less

Efficient Monolithic Perovskite/Silicon Tandem Solar Cell with Cell Area >1 cm(2).

PubMed

Werner, Jérémie; Weng, Ching-Hsun; Walter, Arnaud; Fesquet, Luc; Seif, Johannes Peter; De Wolf, Stefaan; Niesen, Bjoern; Ballif, Christophe

2016-01-07

Monolithic perovskite/crystalline silicon tandem solar cells hold great promise for further performance improvement of well-established silicon photovoltaics; however, monolithic tandem integration is challenging, evidenced by the modest performances and small-area devices reported so far. Here we present first a low-temperature process for semitransparent perovskite solar cells, yielding efficiencies of up to 14.5%. Then, we implement this process to fabricate monolithic perovskite/silicon heterojunction tandem solar cells yielding efficiencies of up to 21.2 and 19.2% for cell areas of 0.17 and 1.22 cm(2), respectively. Both efficiencies are well above those of the involved subcells. These single-junction perovskite and tandem solar cells are hysteresis-free and demonstrate steady performance under maximum power point tracking for several minutes. Finally, we present the effects of varying the intermediate recombination layer and hole transport layer thicknesses on tandem cell photocurrent generation, experimentally and by transfer matrix simulations.

Implementation of real-time digital signal processing systems

NASA Technical Reports Server (NTRS)

Narasimha, M.; Peterson, A.; Narayan, S.

1978-01-01

Special purpose hardware implementation of DFT Computers and digital filters is considered in the light of newly introduced algorithms and IC devices. Recent work by Winograd on high-speed convolution techniques for computing short length DFT's, has motivated the development of more efficient algorithms, compared to the FFT, for evaluating the transform of longer sequences. Among these, prime factor algorithms appear suitable for special purpose hardware implementations. Architectural considerations in designing DFT computers based on these algorithms are discussed. With the availability of monolithic multiplier-accumulators, a direct implementation of IIR and FIR filters, using random access memories in place of shift registers, appears attractive. The memory addressing scheme involved in such implementations is discussed. A simple counter set-up to address the data memory in the realization of FIR filters is also described. The combination of a set of simple filters (weighting network) and a DFT computer is shown to realize a bank of uniform bandpass filters. The usefulness of this concept in arriving at a modular design for a million channel spectrum analyzer, based on microprocessors, is discussed.

A Simple Configuration for Quantitative Phase Contrast Microscopy of Transmissible Samples

NASA Astrophysics Data System (ADS)

Sengupta, Chandan; Dasgupta, Koustav; Bhattacharya, K.

Phase microscopy attempts to visualize and quantify the phase distribution of samples which are otherwise invisible under microscope without the use of stains. The two principal approaches to phase microscopy are essentially those of Fourier plane modulation and interferometric techniques. Although the former, first proposed by Zernike, had been the harbinger of phase microscopy, it was the latter that allowed for quantitative evaluation of phase samples. However interferometric techniques are fraught with associated problems such as complicated setup involving mirrors and beam-splitters, the need for a matched objective in the reference arm and also the need for vibration isolation. The present work proposes a single element cube beam-splitter (CBS) interferometer combined with a microscope objective (MO) for interference microscopy. Because of the monolithic nature of the interferometer, the system is almost insensitive to vibrations and relatively simple to align. It will be shown that phase shifting properties may also be introduced by suitable and proper use of polarizing devices. Initial results showing the quantitative three dimensional phase profiles of simulated and actual biological specimens are presented.

25. PLAN OF SPILLWAY SHOWING INDEX TO MONOLITHS. Sheet S18, ...

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

25. PLAN OF SPILLWAY SHOWING INDEX TO MONOLITHS. Sheet S-18, July, 1939. File no. SA 342/15. - Prado Dam, Spillway, Santa Ana River near junction of State Highways 71 & 91, Corona, Riverside County, CA

Developing Intepretive Soil Education Displays.

ERIC Educational Resources Information Center

Hansmeyer, T. L.; Cooper, T. H.

1993-01-01

Describes several soil educational displays developed for park and nature center trails. Displays include full-scale soil monoliths displayed along the trails with explanations on why and how the soils are different, and micro-monoliths exhibiting the different soil types. (MDH)

Package Holds Five Monolithic Microwave Integrated Circuits

NASA Technical Reports Server (NTRS)

Mysoor, Narayan R.; Decker, D. Richard; Olson, Hilding M.

1996-01-01

Packages protect and hold monolithic microwave integrated circuit (MMIC) chips while providing dc and radio-frequency (RF) electrical connections for chips undergoing development. Required to be compact, lightweight, and rugged. Designed to minimize undesired resonances, reflections, losses, and impedance mismatches.

Designing astrophysics missions for NASA's Space Launch System

NASA Astrophysics Data System (ADS)

Stahl, H. Philip; Hopkins, Randall C.; Schnell, Andrew; Smith, David Alan; Jackman, Angela; Warfield, Keith R.

2016-10-01

Large space telescope missions have always been limited by their launch vehicle's mass and volume capacities. The Hubble Space Telescope was specifically designed to fit inside the Space Shuttle and the James Webb Space Telescope was specifically designed to fit inside an Ariane 5. Astrophysicists desire even larger space telescopes. NASA's "Enduring Quests Daring Visions" report calls for an 8- to 16-m Large UV-Optical-IR (LUVOIR) Surveyor mission to enable ultrahigh-contrast spectroscopy and coronagraphy. Association of Universities for Research in Astronomy's "From Cosmic Birth to Living Earth" report calls for a 12-m class High-Definition Space Telescope to pursue transformational scientific discoveries. NASA's "Planning for the 2020 Decadal Survey" calls for a Habitable Exoplanet Imaging (HabEx) and an LUVOIR as well as Far-IR and an X-ray Surveyor missions. Packaging larger space telescopes into existing launch vehicles is a significant engineering complexity challenge that drives cost and risk. NASA's planned Space Launch System (SLS), with its 8- or 10-m diameter fairings and ability to deliver 35 to 45 mt of payload to Sun-Earth-Lagrange-2, mitigates this challenge by fundamentally changing the design paradigm for large space telescopes. This paper introduces the mass and volume capacities of the planned SLS, provides a simple mass allocation recipe for designing large space telescope missions to this capacity, and gives three specific mission concept implementation examples: a 4-m monolithic off-axis telescope, an 8-m monolithic on-axis telescope, and a 12-m segmented on-axis telescope.

Realization and optimization of a 1 ns pulsewidth multi-stage 250 kW peak power monolithic Yb doped fiber amplifier at 1064 nm

NASA Astrophysics Data System (ADS)

Morasse, Bertrand; Plourde, Estéban

2017-02-01

We present a simple way to achieve and optimize hundreds of kW peak power pulsed output using a monolithic amplifier chain based on solid core double cladding fiber tightly packaged. A fiber pigtailed current driven diode is used to produce nanosecond pulses at 1064 nm. We present how to optimize the use of Fabry-Perot versus DFB type diode along with the proper wavelength locking using a fiber Bragg grating. The optimization of the two pre-amplifiers with respect to the pump wavelength and Yb inversions is presented. We explain how to manage ASE using core and cladding pumping and by using single pass and double pass amplifier. ASE rejection within the Yb fiber itself and with the use of bandpass filter is discussed. Maximizing the amplifier conversion efficiency with regards to the fiber parameters, glass matrix and signal wavelength is described in details. We present how to achieve high peak power at the power amplifier stage using large core/cladding diameter ratio highly doped Yb fibers pumped at 975 nm. The effect of pump bleaching on the effective Yb fiber length is analyzed carefully. We demonstrate that counter-pumping brings little advantage in very short length amplifier. Dealing with the self-pulsation limit of stimulated Brillouin scattering is presented with the adjustment of the seed pulsewidth and linewidth. Future prospects for doubling the output peak power are discussed.

Uricase-free on-demand colorimetric biosensing of uric acid enabled by integrated CoP nanosheet arrays as a monolithic peroxidase mimic.

PubMed

He, Yanfang; Qi, Fei; Niu, Xiangheng; Zhang, Wenchi; Zhang, Xifeng; Pan, Jianming

2018-08-27

In clinical diagnosis, monitoring of uric acid (UA) is generally realized by combining uricase with natural peroxidase. The use of bio-enzymes, however, shadows some highlights of these methods due to their vulnerable activities against environments. Herein, we report a novel biosensor for the natural enzyme-free colorimetric detection of UA by using CoP nanosheet arrays grown on Ni foam (NF) as a monolithic peroxidase mimic. The integrated nanozyme can be put into and taken out from reaction systems conveniently with only tweezers, making it possible for on-demand analysis. As demonstrated, the obtained CoP/NF exhibits outstanding peroxidase-like activity to trigger the oxidation reaction of colorless 3,3'5,5'-tetramethylbenzidine (TMB) to a blue product (TMBox) mediated by H 2 O 2 . It is found that the blue TMBox can be reduced to colorless TMB again by UA selectively, thus the presence of UA in solutions will suppress the color reaction of TMB. Based on this principle, an uricase-free biosensor is developed for the photometric determination of UA, providing a wide detection range of 1-200 μM and a limit of detection down to 1.0 μM. In addition, the fabricated biosensor can be applied for measuring UA in clinical samples with merits of simple operation and good reliability, exhibiting its great promise in clinical diagnosis. Copyright © 2018 Elsevier B.V. All rights reserved.