CO2 Separation Using Thermally Optimized Membranes: A Comprehensive Project Report (2000 - 2007)

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

N /A

2008-03-04

This is a complete (Fiscal Years 2000–2006) collection of the Idaho National Laboratory’s (INL) research and development contributions to the project, “CO2 Separation Using Thermally Optimized Membranes.” The INL scientific contribution to the project has varied due to the fluctuations in funding from year to year. The focus of the project was polybenzimidazole (PBI) membranes and developing PBI compounds (both substitution and blends) that provide good film formation and gas separation membranes. The underlying problem with PBI is its poor solubility in common solvents. Typically, PBI is dissolved in “aggressive” solvents, like N,N-dimethylacetamide (DMAc) and N methylpyrrolidone (NMP). The INLmore » FY-03 research was directed toward making soluble N-substituted PBI polymers, where INL was very successful. Many different types of modified PBI polymers were synthesized; however, film formation proved to be a big problem with both unsubstituted and N-substituted PBIs. Therefore, INL researchers directed their attention to using plasticizers or additives to make the membranes more stable and workable. During the course of these studies, other high-performance polymers (like polyamides and polyimides) were found to be better materials, which could be used either by themselves or blends with PBI. These alternative high-performance polymers provided the best pathway forward for soluble high-temperature polymers with good stable film formation properties. At present, the VTEC polyimides (product of RBI, Inc.) are the best film formers that exhibit high-temperature resistance. INL’s gas testing results show VTEC polyimides have very good gas selectivities for both H2/CO2 and CO2/CH4. Overall, these high-performance polymers pointed towards new research areas where INL has gained a greater understanding of polymer film formation and gas separation. These studies are making possible a direct approach to stable polymer-based high-temperature gas separation membranes. This report is separated into several sections due to the complexity of the research and the variation with the development of better high-temperature, gas separation membranes. Several fiscal years are combined because the research and development efforts within those areas crossed fiscal year boundaries.« less

A robust salt-tolerant superoleophobic alginate/graphene oxide aerogel for efficient oil/water separation in marine environments

PubMed Central

Li, Yuqi; Zhang, Hui; Fan, Mizi; Zheng, Peitao; Zhuang, Jiandong; Chen, Lihui

2017-01-01

Marine pollution caused by frequent oil spill accidents has brought about tremendous damages to marine ecological environment. Therefore, the facile large-scale preparation of three-dimensional (3D) porous functional materials with special wettability is in urgent demand. In this study, we report a low-cost and salt-tolerant superoleophobic aerogel for efficient oil/seawater separation. The aerogel is prepared through incorporating graphene oxide (GO) into alginate (ALG) matrix by using a facile combined freeze-drying and ionic cross-linking method. The 3D structure interconnected by ALG and GO ensures the high mechanical strength and good flexibility of the developed aerogel. The rough microstructure combined with the hydrophilicity of the aerogel ensures its excellent underwater superoleophobic and antifouling properties. High-content polysaccharides contained in the aerogel guarantees its excellent salt-tolerant property. More impressively, the developed aerogel can retain its underwater superoleophobicity even after 30 days of immersion in seawater, indicating its good stability in marine environments. Furthermore, the aerogel could separate various oil/water mixtures with high separation efficiency (>99%) and good reusability (at least 40 cycles). The facile fabrication process combined with the excellent separation performance makes it promising for practical applications in marine environments. PMID:28397862

Rapid separation and characterization of diterpenoid alkaloids in processed roots of Aconitum carmichaeli using ultra high performance liquid chromatography coupled with hybrid linear ion trap-Orbitrap tandem mass spectrometry.

PubMed

Xu, Wen; Zhang, Jing; Zhu, Dayuan; Huang, Juan; Huang, Zhihai; Bai, Junqi; Qiu, Xiaohui

2014-10-01

The lateral root of Aconitum carmichaeli, a popular traditional Chinese medicine, has been widely used to treat rheumatic diseases. For decades, diterpenoid alkaloids have dominated the phytochemical and biomedical research on this plant. In this study, a rapid and sensitive method based on ultra high performance liquid chromatography coupled with linear ion trap-Orbitrap tandem mass spectrometry was developed to characterize the diterpenoid alkaloids in Aconitum carmichaeli. Based on an optimized chromatographic condition, more than 120 diterpenoid alkaloids were separated with good resolution. Using a systematic strategy that combines high resolution separation, highly accurate mass measurements and a good understanding of the diagnostic fragment-based fragmentation patterns, these diterpenoid alkaloids were identified or tentatively identified. The identification of these chemicals provided essential data for further phytochemical studies and toxicity research of Aconitum carmichaeli. Moreover, the ultra high performance liquid chromatography with linear ion trap-Orbitrap mass spectrometry platform was an effective and accurate tool for rapid qualitative analysis of secondary metabolite productions from natural resources. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Performance and techno-economic assessment of several solid-liquid separation technologies for processing dilute-acid pretreated corn stover.

PubMed

Sievers, David A; Tao, Ling; Schell, Daniel J

2014-09-01

Solid-liquid separation of pretreated lignocellulosic biomass slurries is a critical unit operation employed in several different processes for production of fuels and chemicals. An effective separation process achieves good recovery of solute (sugars) and efficient dewatering of the biomass slurry. Dilute acid pretreated corn stover slurries were subjected to pressure and vacuum filtration and basket centrifugation to evaluate the technical and economic merits of these technologies. Experimental performance results were used to perform detailed process simulations and economic analysis using a 2000 tonne/day biorefinery model to determine differences between the various filtration methods and their process settings. The filtration processes were able to successfully separate pretreated slurries into liquor and solid fractions with estimated sugar recoveries of at least 95% using a cake washing process. A continuous vacuum belt filter produced the most favorable process economics. Copyright © 2014 Elsevier Ltd. All rights reserved.

Mesoporous Cladophora cellulose separators for lithium-ion batteries

NASA Astrophysics Data System (ADS)

Pan, Ruijun; Cheung, Ocean; Wang, Zhaohui; Tammela, Petter; Huo, Jinxing; Lindh, Jonas; Edström, Kristina; Strømme, Maria; Nyholm, Leif

2016-07-01

Much effort is currently made to develop inexpensive and renewable materials which can replace the polyolefin microporous separators conventionally used in contemporary lithium-ion batteries. In the present work, it is demonstrated that mesoporous Cladophora cellulose (CC) separators constitute very promising alternatives based on their high crystallinity, good thermal stability and straightforward manufacturing. The CC separators, which are fabricated using an undemanding paper-making like process involving vacuum filtration, have a typical thickness of about 35 μm, an average pore size of about 20 nm, a Young's modulus of 5.9 GPa and also exhibit an ionic conductivity of 0.4 mS cm-1 after soaking with 1 M LiPF6 EC: DEC (1/1, v/v) electrolyte. The CC separators are demonstrated to be thermally stable at 150 °C and electrochemically inert in the potential range between 0 and 5 V vs. Li+/Li. A LiFePO4/Li cell containing a CC separator showed good cycling stability with 99.5% discharge capacity retention after 50 cycles at a rate of 0.2 C. These results indicate that the renewable CC separators are well-suited for use in high-performance lithium-ion batteries.

Single laboratory validation of the determination of yohimbine in yohimbe bark and related dietary supplements using UHPLC/UV/MS

USDA-ARS?s Scientific Manuscript database

A single laboratory validation has been performed on a practical ultra high-performance liquid chromatography (UHPLC), diode array detection (DAD), and tandem mass spectrometry (MS) method for determination of yohimbine in yohimbe barks and related dietary supplements. Good separation was achieved u...

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.

Cellulose acetate-based SiO2/TiO2 hybrid microsphere composite aerogel films for water-in-oil emulsion separation

NASA Astrophysics Data System (ADS)

Yang, Xue; Ma, Jianjun; Ling, Jing; Li, Na; Wang, Di; Yue, Fan; Xu, Shimei

2018-03-01

The cellulose acetate (CA)/SiO2-TiO2 hybrid microsphere composite aerogel films were successfully fabricated via water vapor-induced phase inversion of CA solution and simultaneous hydrolysis/condensation of 3-aminopropyltrimethoxysilane (APTMS) and tetrabutyl titanate (TBT) at room temperature. Micro-nano hierarchical structure was constructed on the surface of the film. The film could separate nano-sized surfactant-stabilized water-in-oil emulsions only under gravity. The flux of the film for the emulsion separation was up to 667 L m-2 h-1, while the separation efficiency was up to 99.99 wt%. Meanwhile, the film exhibited excellent stability during multiple cycles. Moreover, the film performed excellent photo-degradation performance under UV light due to the photocatalytic ability of TiO2. Facile preparation, good separation and potential biodegradation maked the CA/SiO2-TiO2 hybrid microsphere composite aerogel films a candidate in oil/water separation application.

An EEG blind source separation algorithm based on a weak exclusion principle.

PubMed

Lan Ma; Blu, Thierry; Wang, William S-Y

2016-08-01

The question of how to separate individual brain and non-brain signals, mixed by volume conduction in electroencephalographic (EEG) and other electrophysiological recordings, is a significant problem in contemporary neuroscience. This study proposes and evaluates a novel EEG Blind Source Separation (BSS) algorithm based on a weak exclusion principle (WEP). The chief point in which it differs from most previous EEG BSS algorithms is that the proposed algorithm is not based upon the hypothesis that the sources are statistically independent. Our first step was to investigate algorithm performance on simulated signals which have ground truth. The purpose of this simulation is to illustrate the proposed algorithm's efficacy. The results show that the proposed algorithm has good separation performance. Then, we used the proposed algorithm to separate real EEG signals from a memory study using a revised version of Sternberg Task. The results show that the proposed algorithm can effectively separate the non-brain and brain sources.

Hydrophobic asymmetric ultrafiltration PVDF membranes: an alternative separator for VFB with excellent stability.

PubMed

Wei, Wenping; Zhang, Huamin; Li, Xianfeng; Zhang, Hongzhang; Li, Yun; Vankelecom, Ivo

2013-02-14

Polyvinylidene fluoride (PVDF) ultrafiltration membranes were investigated for the first time in vanadium redox flow battery (VFB) applications. Surprisingly, PVDF ultrafiltration membranes with hydrophobic pore walls and relatively large pore sizes of several tens of nanometers proved able to separate vanadium ions and protons efficiently, thus being suitable as a VFB separator. The ion selectivity of this new type of VFB membrane could be tuned readily by controlling the membrane morphology via changes in the composition of the membrane casting solution, and the casting thickness. The results showed that the PVDF membranes offered good performances and excellent stability in VFB applications, where it could, performance-wise, truly substitute Nafion in VFB applications, but at a much lower cost.

Polyacrylonitrile Separator for High-Performance Aluminum Batteries with Improved Interface Stability.

PubMed

Elia, Giuseppe Antonio; Ducros, Jean-Baptiste; Sotta, Dane; Delhorbe, Virginie; Brun, Agnès; Marquardt, Krystan; Hahn, Robert

2017-11-08

Herein we report, for the first time, an overall evaluation of commercially available battery separators to be used for aluminum batteries, revealing that most of them are not stable in the highly reactive 1-ethyl-3-methylimidazolium chloride:aluminum trichloride (EMIMCl:AlCl 3 ) electrolyte conventionally employed in rechargeable aluminum batteries. Subsequently, a novel highly stable polyacrylonitrile (PAN) separator obtained by the electrospinning technique for application in high-performance aluminum batteries has been prepared. The developed PAN separator has been fully characterized in terms of morphology, thermal stability, and air permeability, revealing its suitability as a separator for battery applications. Furthermore, extremely good compatibility and improved aluminum interface stability in the highly reactive EMIMCl:AlCl 3 electrolyte were discovered. The use of the PAN separator strongly affects the aluminum dissolution/deposition process, leading to a quite homogeneous deposition compared to that of a glass fiber separator. Finally, the applicability of the PAN separator has been demonstrated in aluminum/graphite cells. The electrochemical tests evidence the full compatibility of the PAN separator in aluminum cells. Furthermore, the aluminum/graphite cells employing the PAN separator are characterized by a slightly higher delivered capacity compared to those employing glass fiber separators, confirming the superior characteristics of the PAN separator as a more reliable separator for the emerging aluminum battery technology.

Electrochemical Properties of LLTO/Fluoropolymer-Shell Cellulose-Core Fibrous Membrane for Separator of High Performance Lithium-Ion Battery

PubMed Central

Huang, Fenglin; Liu, Wenting; Li, Peiying; Ning, Jinxia; Wei, Qufu

2016-01-01

A superfine Li0.33La0.557TiO3 (LLTO, 69.4 nm) was successfully synthesized by a facile solvent-thermal method to enhance the electrochemical properties of the lithium-ion battery separator. Co-axial nanofiber of cellulose and Poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) was prepared by a co-axial electrospinning technique, in which the shell material was PVDF-HFP and the core was cellulose. LLTO superfine nanoparticles were incorporated into the shell of the PVDF-HFP. The core–shell composite nanofibrous membrane showed good wettability (16.5°, contact angle), high porosity (69.77%), and super electrolyte compatibility (497%, electrolyte uptake). It had a higher ionic conductivity (13.897 mS·cm−1) than those of pure polymer fibrous membrane and commercial separator. In addition, the rate capability (155.56 mAh·g−1) was also superior to the compared separator. These excellent performances endowed LLTO composite nanofibrous membrane as a promising separator for high-performance lithium-ion batteries. PMID:28787873

Impact of tuning CO 2-philicity in polydimethylsiloxane-based membranes for carbon dioxide separation

DOE PAGES

Hong, Tao; Chatterjee, Sabornie; Mahurin, Shannon M.; ...

2017-02-22

Amidoxime-functionalized polydimethylsiloxane (AO-PDMSPNB) membranes with various amidoxime compositions were synthesized via ring-opening metathesis polymerization followed by post-polymerization modification. Compared to other previously reported PDMS-based membranes, the amidoxime-functionalized membranes show enhanced CO 2 permeability and CO 2/N 2 selectivity. The overall gas separation performance (CO 2 permeability 6800 Barrer; CO 2/N 2 selectivity 19) of the highest performing membrane exceeds the Robeson upper bound line, and the excellent permeability of the copolymer itself provides great potential for real world applications where huge volumes of gases are separated. This study details how tuning the CO 2-philicity within rubbery polymer matrices influences gasmore » transport properties. Key parameters for tuning gas transport properties are discussed, and the experimental results show good consistency with theoretical calculations. Finally, this study provides a roadmap to enhancing gas separation performance in rubbery polymers by tuning gas solubility selectivity.« less

A trilayer separator with dual function for high performance lithium-sulfur batteries

NASA Astrophysics Data System (ADS)

Song, Rensheng; Fang, Ruopian; Wen, Lei; Shi, Ying; Wang, Shaogang; Li, Feng

2016-01-01

In this article, we propose a trilayer graphene/polypropylene/Al2O3 (GPA) separator with dual function for high performance lithium-sulfur (Li-S) batteries. Graphene is coated on one side of polypropylene (PP) separator, which functions as a conductive layer and an electrolyte reservoir that allows for rapid electron and ion transport. Then Al2O3 particles are coated on the other side to further enhance thermal stability and safety of the graphene coated polypropylene (GCP) separator, which are touched with lithium metal anode in the Li-S battery. The GPA separator shows good thermal stability after heating at 157 °C for 10 min while both GCP and PP separators showing an obvious shrinkage about 10%. The initial discharge specific capacity of Li-S coin cell with a GPA separator could reach 1067.7 mAh g-1 at 0.2C. After 100 discharge/charge cycles, it can still deliver a reversible capacity of as high as 804.4 mAh g-1 with 75% capacity retention. The pouch cells further confirm that the trilayer design has great promise towards practical applications.

Separation performance of cucurbit[7]uril in ionic liquid-based sol-gel coating as stationary phase for capillary gas chromatography.

PubMed

Wang, Xiaogang; Qi, Meiling; Fu, Ruonong

2014-12-05

Here we report the separation performance of a new stationary phase of cucurbit[7]uril (CB7) incorporated into an ionic liquid-based sol-gel coating (CB7-SG) for capillary gas chromatography (GC). The CB7-SG stationary phase showed an average polarity of 455, suggesting its polar nature. Abraham system constants revealed that its major interactions with analytes include H-bond basicity (a), dipole-dipole (s) and dispersive (l) interactions. The CB7-SG stationary phase achieved baseline separation for a wide range of analytes with symmetrical peak shapes and showed advantages over the conventional polar stationary phase that failed to resolve some critical analytes. Also, it exhibited different retention behaviors from the conventional stationary phase in terms of retention times and elution order. Most interestingly, in contrast to the conventional polar phase, the CB7-SG stationary phase exhibited longer retentions for analytes of lower polarity but relatively comparable retentions for polar analytes such as alcohols and phenols. The high resolving ability and unique retention behaviors of the CB7-SG stationary phase may stem from the comprehensive interactions of the aforementioned interactions and shape selectivity. Moreover, the CB7-SG column showed good peak shapes for analytes prone to peak tailing, good thermal stability up to 280°C and separation repeatability with RSD values in the range of 0.01-0.11% for intra-day, 0.04-0.41% for inter-day and 2.5-6.0% for column-to-column, respectively. As demonstrated, the proposed coating method can simultaneously address the solubility problem with CBs for the intended purpose and achieve outstanding GC separation performance. Copyright © 2014 Elsevier B.V. All rights reserved.

Special distraction osteogenesis before bone grafting for alveolar cleft defects to correct maxillary deformities in patients with bilateral cleft lips and palates: distraction osteogenesis performed separately for each bone segment.

PubMed

Mitsukawa, Nobuyuki; Saiga, Atsuomi; Morishita, Tadashi; Satoh, Kaneshige

2014-07-01

Patients with bilateral cleft lips and palates have premaxillary protrusion and characteristic jaw deformities involving three-dimensional malposition of the premaxilla and bilateral maxillary bone segments. This study examined patients with bilateral cleft lips and palates who had deviation and hypoplasia of the premaxillas and bilateral maxillary segments. Before bone grafting, the patients were treated with special distraction performed separately for each bone segment using a halo-type external device. This report describes this novel treatment method which produced good results. The subjects were five patients with severe jaw deformities due to bilateral cleft lip and palate. They were treated with maxillary Le Fort I osteotomy and subsequent distraction performed separately for each bone segment using a halo device. In three of five patients, premaxillary osteotomy was not performed, and osteotomy and distraction were performed only for the right and left lateral segments with severe hypoplasia. All patients achieved distraction close to the desired amount. The widths of the alveolar clefts were narrowed, and satisfactory occlusion and maxillary arch form were achieved. After the surgery, three of five patients underwent bone grafting for bilateral alveolar cleft defects and the bone graft survival was satisfactory. This method had many benefits, including narrowing of alveolar clefts, improvement of maxillary hypoplasia, and achievement of a good maxillary arch form. In addition, subsequent bone grafting for alveolar cleft defects was beneficial, dental prostheses were unnecessary, and frequency of surgery and surgical invasiveness were reduced. This method is a good surgical procedure that should be considered for patients with bilateral cleft lips and palates who have premaxillary protrusion and hypoplasia of the right and left lateral segments. Copyright © 2013 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.

Time-frequency analysis of time-varying modulated signals based on improved energy separation by iterative generalized demodulation

NASA Astrophysics Data System (ADS)

Feng, Zhipeng; Chu, Fulei; Zuo, Ming J.

2011-03-01

Energy separation algorithm is good at tracking instantaneous changes in frequency and amplitude of modulated signals, but it is subject to the constraints of mono-component and narrow band. In most cases, time-varying modulated vibration signals of machinery consist of multiple components, and have so complicated instantaneous frequency trajectories on time-frequency plane that they overlap in frequency domain. For such signals, conventional filters fail to obtain mono-components of narrow band, and their rectangular decomposition of time-frequency plane may split instantaneous frequency trajectories thus resulting in information loss. Regarding the advantage of generalized demodulation method in decomposing multi-component signals into mono-components, an iterative generalized demodulation method is used as a preprocessing tool to separate signals into mono-components, so as to satisfy the requirements by energy separation algorithm. By this improvement, energy separation algorithm can be generalized to a broad range of signals, as long as the instantaneous frequency trajectories of signal components do not intersect on time-frequency plane. Due to the good adaptability of energy separation algorithm to instantaneous changes in signals and the mono-component decomposition nature of generalized demodulation, the derived time-frequency energy distribution has fine resolution and is free from cross term interferences. The good performance of the proposed time-frequency analysis is illustrated by analyses of a simulated signal and the on-site recorded nonstationary vibration signal of a hydroturbine rotor during a shut-down transient process, showing that it has potential to analyze time-varying modulated signals of multi-components.

Initial evaluation of a convection counter streaming galvanization technique of sex separation of human spermatozoa.

PubMed

Daniell, J F; Herbert, C M; Repp, J; Torbit, C A; Wentz, A C

1982-08-01

A new method for separating X and Y human spermatozoa called convection counter streaming galvanization was evaluated. The method was independently performed by this semenology laboratory with the use of the special separation equipment and extending media provided by its developer, Dr. Bhairab C. Bhattacharya. The mean number of Y spermatozoa increased from 48% to 77% in the separated fraction predicted to be Y-enriched. The fraction predicted to be X-enriched increased from a mean of 52% to 77%. The one separation process allowed accumulation of both enriched fractions simultaneously. The separated portions of spermatozoa maintained good motility and penetration of cervical mucus but produced a mean recovery concentration in the X- and Y-enriched fractions of only 15% to 16% of the preseparation concentration.

Accelerating the design of molecularly imprinted nanocomposite membranes modified by Au@polyaniline for selective enrichment and separation of ibuprofen

NASA Astrophysics Data System (ADS)

Wu, Xiuling; Wu, Yilin; Dong, Hongjun; Zhao, Juan; Wang, Chen; Zhou, Shi; Lu, Jian; Yan, Yongsheng; Li, He

2018-01-01

A novel system for harvesting molecularly imprinted nanocomposite membranes (MINcMs) with Au-modified polyaniline (Au@polyaniline) nanocomposite structure was developed for selective enrichment and separation of ibuprofen. This unique nanocomposite structure obviously enhanced the adsorption capacity, perm-selectivity performance, and regeneration ability of MINcMs. The as-prepared MINcMs showed outstanding adsorption capacity (22.02 mg g-1) of ibuprofen, which was four times higher than that of non-imprinted nanocomposite membranes (NINcMs). Furthermore, the selectivity factor of MINcMs for ibuprofen reached up to 4.67 and the perm-selectivity factor β was about 8.74, which indicated MINcMs had a good selective separation performance of ibuprofen. We envision that this novel synthesis method will open a new direction to manipulation of molecularly imprinted membrane materials and provide a simple yet convenient way to selective separation of ibuprofen.

Post-synthetic modification of MIL-101(Cr) with pyridine for high-performance liquid chromatographic separation of tocopherols.

PubMed

Yang, Fang; Yang, Cheng-Xiong; Yan, Xiu-Ping

2015-05-01

Effective separation of tocopherols is challenging and significant due to their structural similarity and important biological role. Here we report the post-synthetic modification of metal-organic framework (MOF) MIL-101(Cr) with pyridine for high-performance liquid chromatographic (HPLC) separation of tocopherols. Baseline separation of four tocopherols was achieved on a pyridine-grafted MIL-101(Cr) packed column within 10 min using hexane/isopropanol (96:4, v/v) as the mobile phase at a flow rate of 0.5 mL min(-1). The pyridine-grafted MIL-101(Cr) packed column gave high column efficiency (85,000 plates m(-1) for δ-tocopherol) and good precision (0.2-0.3% for retention time, 1.8-3.4% for peak area, 2.6-2.7% for peak height), and also offered much better performance than unmodified MIL-101(Cr) and commercial amino-bonded silica packed column for HPLC separation of tocopherols. The results not only show the promising application of pyridine-grafted MIL-101(Cr) as a novel stationary phase for HPLC separation of tocopherols, but also reveal a facile post-modification of MOFs to expand the application of MOFs in separation sciences. Copyright © 2015 Elsevier B.V. All rights reserved.

Prawn Shell Derived Chitin Nanofiber Membranes as Advanced Sustainable Separators for Li/Na-Ion Batteries.

PubMed

Zhang, Tian-Wen; Shen, Bao; Yao, Hong-Bin; Ma, Tao; Lu, Lei-Lei; Zhou, Fei; Yu, Shu-Hong

2017-08-09

Separators, necessary components to isolate cathodes and anodes in Li/Na-ion batteries, are consumed in large amounts per year; thus, their sustainability is a concerning issue for renewable energy storage systems. However, the eco-efficient and environmentally friendly fabrication of separators with a high mechanical strength, excellent thermal stability, and good electrolyte wettability is still challenging. Herein, we reported the fabrication of a new type of separators for Li/Na-ion batteries through the self-assembly of eco-friendly chitin nanofibers derived from prawn shells. We demonstrated that the pore size in the chitin nanofiber membrane (CNM) separator can be tuned by adjusting the amount of pore generation agent (sodium dihydrogen citrate) in the self-assembly process of chitin nanofibers. By optimizing the pore size in CNM separators, the electrochemical performance of the LiFePO 4 /Li half-cell with a CNM separator is comparable to that with a commercialized polypropylene (PP) separator. More attractively, the CNM separator showed a much better performance in the LiFePO 4 /Li cell at 120 °C and Na 3 V 2 (PO 4 ) 3 /Na cell than the PP separator. The proposed fabrication of separators by using natural raw materials will play a significant contribution to the sustainable development of renewable energy storage systems.

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

Hong, Tao; Chatterjee, Sabornie; Mahurin, Shannon M.

Amidoxime-functionalized polydimethylsiloxane (AO-PDMSPNB) membranes with various amidoxime compositions were synthesized via ring-opening metathesis polymerization followed by post-polymerization modification. Compared to other previously reported PDMS-based membranes, the amidoxime-functionalized membranes show enhanced CO 2 permeability and CO 2/N 2 selectivity. The overall gas separation performance (CO 2 permeability 6800 Barrer; CO 2/N 2 selectivity 19) of the highest performing membrane exceeds the Robeson upper bound line, and the excellent permeability of the copolymer itself provides great potential for real world applications where huge volumes of gases are separated. This study details how tuning the CO 2-philicity within rubbery polymer matrices influences gasmore » transport properties. Key parameters for tuning gas transport properties are discussed, and the experimental results show good consistency with theoretical calculations. Finally, this study provides a roadmap to enhancing gas separation performance in rubbery polymers by tuning gas solubility selectivity.« less

Deep Learning Based Binaural Speech Separation in Reverberant Environments.

PubMed

Zhang, Xueliang; Wang, DeLiang

2017-05-01

Speech signal is usually degraded by room reverberation and additive noises in real environments. This paper focuses on separating target speech signal in reverberant conditions from binaural inputs. Binaural separation is formulated as a supervised learning problem, and we employ deep learning to map from both spatial and spectral features to a training target. With binaural inputs, we first apply a fixed beamformer and then extract several spectral features. A new spatial feature is proposed and extracted to complement the spectral features. The training target is the recently suggested ideal ratio mask. Systematic evaluations and comparisons show that the proposed system achieves very good separation performance and substantially outperforms related algorithms under challenging multi-source and reverberant environments.

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.

[Studies on determination of p-aminophenol and its related compounds prepared with catalytic hydrogenation by reversed-phase high performance liquid chromatography].

PubMed

Li, S; Gu, H; Zheng, M; Zhan, Y

1997-07-01

Catalytic hydrogenation of nitrobenzene with supported palladium catalyst is a new method to produce p-aminophenol. p-Aminophenol, aniline and 4,4'-diaminodiphenyl ether obtained from this method were determined by reversed phase high performance liquid chromatography. The factors, e.g., concentration of methanol, pH and ionic strength which could affect separation efficiency were studied. UV spectra of p-aminophenol, aniline and 4,4'-diaminodiphenyl ether were recorded. Good separation was performed by using a 100 mm x 4.6 mm column with 5 microm Hypersil ODS, a mixture of 60% aqueous 8.0 mmol/L KH2PO4 buffered to 6.5 with 4.0 mmol/L Na2HPO4 and 40% methanol as mobile phase at a flow rate of 1.0 mL/min, and UV spectrophotometric detector at 232 nm wavelength. The calibration curves of p-aminophenol, aniline and 4,4'-diaminodiphenyl ether have good linearity over concentration range of 5-250, 5-150 and 0.2-120 mg/L, respectively. Minimum detectable limits at a signal-to-noise ratio of 2 were 0.1, 0.6 and 0.6 ng. This method has been applied to analysis of the reaction products of ultrasonic catalytic hydrogenation and industrial samples with good results and reproducibility.

Semi-preparative asymmetrical flow field-flow fractionation: A closer look at channel dimensions and separation performance.

PubMed

Bria, Carmen R M; Skelly, Patrick W; Morse, James R; Schaak, Raymond E; Williams, S Kim Ratanathanawongs

2017-05-26

The design and performance of a semi-preparative asymmetrical flow field-flow fractionation (SP-AF4) channel are investigated with the objective of better understanding and exploiting the relationship between channel dimensions, sample loading, and resolution. Most size-based separations of nanometer and submicrometer particles are currently limited to analytical scale quantities (<100μg). However, there is a strong need to fractionate and collect larger quantities so that fundamental properties of the more narrowly dispersed fractions can be studied using additional characterization methods and for subsequent applications. In this work, dimensions of the spacer that defines the form of SP-AF4 channels are varied and their performances are assessed with respect to sample focusing position and loading. Separations are performed in aqueous and organic carrier fluids. A critical evaluation of channel dimensions showed that increasing the channel breadth is a practical and effective route to maintaining separation resolution while increasing sample loads to milligram quantities. Good size resolution (∼1.0) is achieved for separations of 10mg of 50 and 100nm silica nanoparticles suspended in water and up to 0.6mg of ∼10 to 35nm inorganic hybrid nanoparticles suspended in tetrahydrofuran. This work represents important advances in the understanding of SP-AF4 separations and extends sample loading capacities in both aqueous and organic solvents. Copyright © 2017 Elsevier B.V. All rights reserved.

Simultaneous analysis of tert-butylhydroquinone, tert-butylquinone, butylated hydroxytoluene, 2-tert-butyl-4-hydroxyanisole, 3-tert-butyl-4-hydroxyanisole, α-tocopherol, γ-tocopherol, and δ-tocopherol in edible oils by normal-phase high performance liquid chromatography.

PubMed

Li, Jun; Bi, Yanlan; Sun, Shangde; Peng, Dan

2017-11-01

A normal-phase high performance liquid chromatography method for the simultaneous determination of tert-butylhydroquinone, tert-butylquinone, butylated hydroxytoluene, 2-tert-butyl-4-hydroxyanisole, 3-tert-butyl-4-hydroxyanisole, α-tocopherol, γ-tocopherol, and δ-tocopherol in edible oils was investigated. A silica column was used to separate the analytes with the gradient elution. An ultraviolet-visible detector was set at dual wavelengths mode (280 and 310nm). The column temperature was 30°C. The analytes were directly extracted with methanol. Results showed that the normal-phase high performance liquid chromatography method performed well with wide liner ranges (0.10∼500.00μg/mL, R 2 >0.9998), low limits of detection and quantitation (below 0.40 and 1.21μg/mL, respectively), and good recoveries (81.38∼102.34% in soybean oils and 83.03∼100.79% in lard, respectively). The reduction of tert-butylquinone caused by the reverse-phase high performance liquid chromatography during the injection was avoided with the current normal-phase method. The two isomers of butylated hydroxyanisole can also be separated with good resolution. Copyright © 2017 Elsevier Ltd. All rights reserved.

Determination of MDMA, MDEA and MDA in urine by high performance liquid chromatography with fluorescence detection.

PubMed

da Costa, José Luiz; da Matta Chasin, Alice Aparecida

2004-11-05

This paper describes the development and validation of analytical methodology for the determination of the use of MDMA, MDEA and MDA in urine. After a simple liquid extraction, the analyses were carried out on a high performance liquid chromatography (HPLC) in an octadecyl column, with fluorescence detection. The mobile phase using a sodium dodecyl sulfate ion-pairing reagent allows good separation and efficiency. The method showed good linearity and precision. Recovery was between 85 and 102% and detection limits were 10, 15 and 20 ng/ml for MDA, MDMA and MDEA, respectively. No interfering substances were detected with fluorescence detection.

40 CFR 792.49 - Laboratory operation areas.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 32 2011-07-01 2011-07-01 false Laboratory operation areas. 792.49... CONTROL ACT (CONTINUED) GOOD LABORATORY PRACTICE STANDARDS Facilities § 792.49 Laboratory operation areas. Separate laboratory space and other space shall be provided, as needed, for the performance of the routine...

Ultrahigh PEMFC performance of a thin-film, dual-electrode assembly with tailored electrode morphology.

PubMed

Jung, Chi-Young; Kim, Tae-Hyun; Yi, Sung-Chul

2014-02-01

A dual-electrode membrane electrode assembly (MEA) for proton exchange membrane fuel cells with enhanced polarization under zero relative humidity (RH) is fabricated by introducing a phase-separated morphology in an agglomerated catalyst layer of Pt/C (platinum on carbon black) and Nafion. In the catalyst layer, a sufficient level of phase separation is achieved by dispersing the Pt catalyst and the Nafion dispersion in a mixed-solvent system (propane-1,2,3-triol/1-methyl-2-pyrrolidinone).The high polymer chain mobility results in improved water uptake and regular pore-size distribution with small pore diameters. The electrochemical performance of the dual-film electrode assembly with different levels of phase separation is compared to conventional electrode assemblies. As a result, good performance at 0 % RH is obtained because self-humidification is dramatically improved by attaching this dense and phase-separated catalytic overlayer onto the conventional catalyst layer. A MEA prepared using the thin-film, dual-layered electrode exhibits 39-fold increased RH stability and 28-fold improved start-up recovery time during the on-off operation relative to the conventional device. We demonstrate the successful operation of the dual-layered electrode comprised of discriminatively phase-separated agglomerates with an ultrahigh zero RH fuel-cell performance reaching over 95 % performance of a fully humidified MEA. Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Preparation, characterization, and performance evaluation of UiO-66 analogues as stationary phase in HPLC for the separation of substituted benzenes and polycyclic aromatic hydrocarbons

PubMed Central

Yan, Zengguang; Li, Jianrong; Xie, Yabo; Bai, Liping; Jiang, Lin; Li, Fasheng

2017-01-01

UiO-66 analogues are good candidates as stationary phase in HPLC because of their chemical/thermal stability, large surface area, and two cage structures. Here, two UiO-66 analogues, UiO-66-NH2 and UiO-67, were synthesized and used as stationary phase in HPLC to evaluate their performance in the separation of substituted benzenes (SBs) and polycyclic aromatic hydrocarbons (PAHs). The results showed that SBs could be well separated on UiO-66-NH2 column but not on UiO-67 column. Nonetheless, PAHs could be well separated on UiO-67 column. The separation mechanisms of SBs and PAHs on UiO-66 analogues may be involved in the pore size and functional group in the frameworks of UiO-66 analogues. Introduction of the–NH2 into UiO-66 significantly reduced its adsorption capacity for SB congeners, which resulted in less separation of SBs on UiO-66-NH2. As for the separation of PAHs on UiO-67 column, the π-π stacking effect was supposed to play a vital role. PMID:28582453

Preparation, characterization, and performance evaluation of UiO-66 analogues as stationary phase in HPLC for the separation of substituted benzenes and polycyclic aromatic hydrocarbons.

PubMed

Zhao, Weiwei; Zhang, Chaoyan; Yan, Zengguang; Zhou, Youya; Li, Jianrong; Xie, Yabo; Bai, Liping; Jiang, Lin; Li, Fasheng

2017-01-01

UiO-66 analogues are good candidates as stationary phase in HPLC because of their chemical/thermal stability, large surface area, and two cage structures. Here, two UiO-66 analogues, UiO-66-NH2 and UiO-67, were synthesized and used as stationary phase in HPLC to evaluate their performance in the separation of substituted benzenes (SBs) and polycyclic aromatic hydrocarbons (PAHs). The results showed that SBs could be well separated on UiO-66-NH2 column but not on UiO-67 column. Nonetheless, PAHs could be well separated on UiO-67 column. The separation mechanisms of SBs and PAHs on UiO-66 analogues may be involved in the pore size and functional group in the frameworks of UiO-66 analogues. Introduction of the-NH2 into UiO-66 significantly reduced its adsorption capacity for SB congeners, which resulted in less separation of SBs on UiO-66-NH2. As for the separation of PAHs on UiO-67 column, the π-π stacking effect was supposed to play a vital role.

Separation analysis of macrolide antibiotics with good performance on a positively charged C18HCE column.

PubMed

Wei, Jie; Shen, Aijin; Yan, Jingyu; Jin, Gaowa; Yang, Bingcheng; Guo, Zhimou; Zhang, Feifang; Liang, Xinmiao

2016-03-01

The separation of basic macrolide antibiotics suffers from peak tailing and poor efficiency on traditional silica-based reversed-phase liquid chromatography columns. In this work, a C18HCE column with positively charged surface was applied to the separation of macrolides. Compared with an Acquity BEH C18 column, the C18HCE column exhibited superior performance in the aspect of peak shape and separation efficiency. The screening of mobile phase additives including formic acid, acetic acid and ammonium formate indicated that formic acid was preferable for providing symmetrical peak shapes. Moreover, the influence of formic acid content was investigated. Analysis speed and mass spectrometry compatibility were also taken into account when optimizing the separation conditions for liquid chromatography coupled with tandem mass spectrometry. The developed method was successfully utilized for the determination of macrolide residues in a honey sample. Azithromycin was chosen as the internal standard for the quantitation of spiramycin and tilmicosin, while roxithromycin was used for erythromycin, tylosin, clarithromycin, josamycin and acetylisovaleryltylosin. Good correlation coefficients (r(2) > 0.9938) for all macrolides were obtained. The intra-day and inter-day recoveries were 73.7-134.7% and 80.7-119.7% with relative standard deviations of 2.5-8.0% and 3.9-16.1%, respectively. Outstanding sensitivity with limits of quantitation (S/N ≥ 10) of 0.02-1 μg/kg and limits of detection (S/N ≥ 3) of 0.01-0.5 μg/kg were achieved. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

[Preparation and performance characterization of gold nanoparticles modified chiral capillary electrochromatography stationary phase].

PubMed

Xiong, Lele; Li, Ruijun; Ji, Yibing

2017-07-08

Gold nanoparticles (GNPs, 15 nm) were prepared and introduced to amino groups derived silica monolithic column. Bovine serum albumin (BSA) was immobilized via covalent modification method onto the carboxylic functionalized GNPs to afford chiral stationary phase (CSP) for enantioseparation. GNPs were well dispersed and successfully incorporated onto the columns with the contents as high as 17.18% by characterization method such as transmission electron microscopy (TEM), ultraviolet (UV)-visible absorption spectra and scanning electron microscopy (SEM). The preparation conditions of the BSA modified CSP were optimized and 10% (v/v) 3-aminopropyltriethoxysilane (APTES) and 15 g/L BSA were selected as appropriate reaction conditions. The enantioseparation performance of the BSA modified CSP has been investigated by capillary electrochromatography (CEC). Enantiomers of tryptophan, ephedrine and atenolol were resolved, and the baseline separation of tryptophan was achieved. Meanwhile, the influences of pH value, buffer concentrations and applied voltages used on the chiral separation were studied, and the optimal separation conditions were 10 mmol/L phosphate buffer at pH 7.4 and 15 kV applied voltages. In comparison with the BSA modified CSP prepared by physical adsorption, the CSP prepared by covalent modification method had better separation results, and the analytes could be separated directly without pre-column derivatization. In addition, the prepared BSA modified CSP exhibited good run to run repeatability with relative standard deviations (RSDs) of the migration times and selectivity factors not more than 2.3% and 0.96%, respectively. This work offers a good thinking for modification with other proteins or other types of chiral selectors.

Gas-Liquid Flows and Phase Separation

NASA Technical Reports Server (NTRS)

McQuillen, John

2004-01-01

Common issues for space system designers include:Ability to Verify Performance in Normal Gravity prior to Deployment; System Stability; Phase Accumulation & Shedding; Phase Separation; Flow Distribution through Tees & Manifolds Boiling Crisis; Heat Transfer Coefficient; and Pressure Drop.The report concludes:Guidance similar to "A design that operates in a single phase is less complex than a design that has two-phase flow" is not always true considering the amount of effort spent on pressurizing, subcooling and phase separators to ensure single phase operation. While there is still much to learn about two-phase flow in reduced gravity, we have a good start. Focus now needs to be directed more towards system level problems .

Nano-TiO2 decorated carbon coating on the separator to physically and chemically suppress the shuttle effect for lithium-sulfur battery

NASA Astrophysics Data System (ADS)

Shao, Hongyuan; Wang, Weikun; Zhang, Hao; Wang, Anbang; Chen, Xiaonong; Huang, Yaqin

2018-02-01

Despite recent progress in designing modified separators for lithium-sulfur (Li-S) batteries, detail in optimizing the synergistic effect between chemical and physical immobilization for lithium polysulfides (LiPS) in modified separator hasn't been investigated totally. Here, a nano-TiO2 decorated carbon layer (T-DCL) has been successfully applied to modify separator for the Li-S battery. The results indicate that appropriate weight percentage of nano-TiO2 uniformly distributed in conductive carbon layer is effective to chemically and physically immobilize for LiPS, and promote the electron transfer during discharge/charge process. The performance of the modified Li-S battery with T-DCL separator are significantly enhanced, with a specific capacity of 883 mAh g-1 retained after 180 cycles at 0.1 C and 762 mAh g-1 retained after 200 cycles at 0.5C, which are much higher than that of separators only coated with TiO2 layer or conductive carbon layer. Besides, the separator coated with T-DCL also shows low electrochemical impedance and good lithium anode protection. These results indicate that separator with T-DCL is promising to balance the physical and chemical LiPS trapping effect, and optimize the electrochemical performance for Li-S battery.

The chiral separation of triazole pesticides enantiomers by amylose-tris (3,5-dimethylphenylcarbamate) chiral stationary phase.

PubMed

Wang, Peng; Liu, Donghui; Jiang, Shuren; Xu, Yangguang; Zhou, Zhiqiang

2008-10-01

The amylose-tris(3,5-dimethylphenylcarbamate) chiral stationary phase was synthesized and used to separate the enantiomers of triazole pesticides by high-performance liquid chromatography. The mobile phase was n-hexane-isopropanol applying a flow rate of 1.0 mL/min. Six triazole pesticides were enantioselectively separated. Myclobutanil, paclobutrazol, tebuconazole, and uniconazole obtained complete separation with the resolution factors of 5.73, 2.99, 1.72, and 2.07, respectively, and imazalil and diniconazole obtained partial separation with the resolution factors of 0.79 and 0.77 under the optimized conditions. The effect of the content of isopropanol as well as column temperature on the separation was investigated. A circular dichroism detector was used to identify the enantiomers and determine the elution orders. The results showed the low temperature was good for the chiral separation except for diniconazole. The thermodynamic parameters calculated based on linear Van't Hoff plots showed the chiral separations were controlled by enthalpy.

The reliability of wind power systems in the UK

NASA Astrophysics Data System (ADS)

Newton, K.

A methodology has been developed to evaluate the performance of geographically distributed wind power systems. Results are presented for three widely separated sites based on measured meteorological data obtained over a 17-yr period. The effects of including energy storage were investigated and 150-hr storage found to be a good compromise between store capacity and system performance. When used to provide space heating, the system could have reduced the 17-yr peak demand from conventional sources (smoothed by the storage and geographical separation of sites) by an amount comparable to the mean output of the wind-system, whether or not turbines at the three sites were interconnected by the National Grid. In contrast, the fuel saving capability of the system was found to be comparatively insensitive either to storage period or geographical separation of sites; the system would have been capable of providing up to 90 percent of the total requirement. Results are also given for individual sites to indicate the possible performance of district heating schemes or domestic systems.

Electroactive polymer based porous membranes for energy storage applications

NASA Astrophysics Data System (ADS)

Costa, Carlos Miguel da Silva

In the field of mobile applications the efficient storage of energy is one of the most critical issues. Lithium ion batteries are lighter, cheaper, show higher energy density (210Wh kg-1), no memory effect, longer service-life and higher number of charge/discharge cycles than other battery solutions. The separator membrane is placed between the anode and cathode and serves as the medium for the transfer of charge, being a critical components for the performance of the batteries. Polymers such as PVDF and its copolymers poly(vinylidene fluoride-co-trifluoroethylene), P(VDF-TrFE), poly(vinylidene fluoride-co-hexafluoropropylene), P(VDF-HFP), and poly(vinylidene fluoride-co-chlorotrifluoroethylene), P(VDF-CTFE) are increasingly investigated for their use as battery separators due to their high polarity, excellent thermal and mechanical properties, controllable porosity and wettability by organic solvents, being also chemically inert and stable in cathodic environment. Despite previous works in some of the PVDF co-polymers, there is no systematic investigations on poly(vinylidene fluoride-trifluoroethylene), P(VDF-TrFE), despite its large potential for this specific application. The objective of this work is thus establish the suitability of P(VDF-TrFE) for battery separators and to control of its structure, stability and ionic conductivity in order to increase performance of the material as battery separators. It is shown that solvent evaporation at room temperature allows the preparation of membranes with degrees of porosity from 70% to 80% leading to electrolyte solution uptakes from 250% up to 600%. The preparation of composites of P(VDF-TrFE) with lithium salts allows ionic conductivity values of the electrolytes of 2.3x10. -6 S/cm at 120 °C. These composites show good overall electrochemicalstability. A novel type of polymer blend based on poly(vinylidene fluoride-trifluoroethylene)/poly(ethylene oxide), P(VDF-TrFE)/PEO, was prepared and it was found that the microstructure, hydrophilicity and electrolyte uptake strongly depend on PEO content within the blend. For this blend, the best value of ionic conductivity at room temperature was 0.25 mS cm-1 for the 60/40 membrane. It was also verified that the ionic conductivity of the membrane is depend on the anion size of the salts present in the electrolyte solution, affecting also the electrolyte uptake value. Batteries fabricated with the separators developed in this work within Li/LiFePO4 and Li/Sn-C cells revealed very good cycling performance even at high current rates and 100% of depth of discharge (DOD), approaching the results achieved in liquid electrolytes. Good rate capability was observed in Li/LiFePO4 cathode cells, being able to deliver at 2C more that 90% of the capacity discharged at 0.1C. These results, in conjunction with the approximately 100% coulombic efficiency, indicate very good electrolyte/electrode compatibility. Thus, the developed materials showed suitable thermal, mechanical and electrochemical characteristics as well as high performance in battery applications, indicating the possibility of fabricating lithium-ion batteries with the battery separators developed in this work.

Baseline strength can influence the ability of salivary free testosterone to predict squat and sprinting performance.

PubMed

Crewther, Blair T; Cook, Christian J; Gaviglio, Chris M; Kilduff, Liam P; Drawer, Scott

2012-01-01

The objective of this study was to determine if salivary free testosterone can predict an athlete's performance during back squats and sprints over time and the influence baseline strength on this relationship. Ten weight-trained male athletes were divided into 2 groups based on their 1 repetition maximum (1RM) squats, good squatters (1RM > 2.0 × body weight, n = 5) and average squatters (1RM < 1.9 × body weight, n = 5). The good squatters were stronger than the average squatters (p < 0.05). Each subject was assessed for squat 1RM and 10-m sprint times on 10 separate occasions over a 40-day period. A saliva sample was collected before testing and assayed for free testosterone and cortisol. The pooled testosterone correlations were strong and significant in the good squatters (r = 0.92 for squats, r = -0.87 for sprints, p < 0.01), but not significant for the average squatters (r = 0.35 for squats, r = -0.18 for sprints). Cortisol showed no significant correlations with 1RM squat and 10-m sprint performance, and no differences were identified between the 2 squatting groups. In summary, these results suggest that free testosterone is a strong individual predictor of squat and sprinting performance in individuals with relatively high strength levels but a poor predictor in less strong individuals. This information can assist coaches, trainers, and performance scientists working with stronger weight-trained athletes, for example, the preworkout measurement of free testosterone could indicate likely training outcomes or a readiness to train at a certain intensity level, especially if real-time measurements are made. Our results also highlight the need to separate group and individual hormonal data during the repeated testing of athletes with variable strength levels.

Microfluidic thread based electroanalytical system for green chromatographic separations.

PubMed

Agustini, Deonir; Fedalto, Lucas; Bergamini, Márcio F; Marcolino-Junior, Luiz Humberto

2018-02-13

The use of miniaturized chromatographic systems is an important strategy for reducing the consumption of supplies related to separations, allowing the development of more sustainable analytical methodologies. However, the high cost and complexity in the production of these systems combined with the operational difficulties and the need for the use of solvent and sample pretreatment are challenges to be overcome in order to make the chromatographic methods greener. Here, we report the construction and development of a low cost microfluidic system for green and solvent-free chromatographic separations with electrochemical detection integrated into cotton threads without the use of any mechanical pumping to transport the solutions. The manufacture of the proposed system was performed by simple assembly of the components, with the separation of the species based on an ion exchange mechanism and detection using gold electrodes manufactured directly on the cotton threads. A linear range of 0.025-5.0 mM was obtained for the effective separation of ascorbic acid (AA) and dopamine (DA) with detection limits of 2.89 μM (for AA) and 4.41 μM (for DA). Each analysis was performed at a low cost (less than 0.01 dollars), and with a small volume of waste generated (107.1 μL). So, the proposed system was successfully employed to determine the levels of AA and DA present in the tears of healthy volunteers without sample pretreatment, indicating the good analytical performance of the system and the possibility of performing greener chromatographic separations.

Design of a new abrasive slurry jet generator

NASA Astrophysics Data System (ADS)

Wang, F. C.; Shi, L. L.; Guo, C. W.

2017-12-01

With the advantages of a low system working pressure, good jet convergence and high cutting quality, abrasive slurry jet (ASJ) has broad application prospects in material cutting and equipment cleaning. Considering that the generator plays a crucial role in ASJ system, the paper designed a new type ASJ generator using an electric oil pump, a separate plunger cylinder, and a spring energized seal. According to the determining of structure shape, size and seal type, a new ASJ generator has been manufactured out and tested by a series of experiments. The new generator separates the abrasive slurry from the dynamic hydraulic oil, which can improve the service life of the ASJ system. And the new ASJ system can reach 40 MPa and has good performance in jet convergence, which deserves to popularization and application in materials machining.

Determination of some phenolic compounds in red wine by RP-HPLC: method development and validation.

PubMed

Burin, Vívian Maria; Arcari, Stefany Grützmann; Costa, Léa Luzia Freitas; Bordignon-Luiz, Marilde T

2011-09-01

A methodology employing reversed-phase high-performance liquid chromatography (RP-HPLC) was developed and validated for simultaneous determination of five phenolic compounds in red wine. The chromatographic separation was carried out in a C(18) column with water acidify with acetic acid (pH 2.6) (solvent A) and 20% solvent A and 80% acetonitrile (solvent B) as the mobile phase. The validation parameters included: selectivity, linearity, range, limits of detection and quantitation, precision and accuracy, using an internal standard. All calibration curves were linear (R(2) > 0.999) within the range, and good precision (RSD < 2.6%) and recovery (80-120%) was obtained for all compounds. This method was applied to quantify phenolics in red wine samples from Santa Catarina State, Brazil, and good separation peaks for phenolic compounds in these wines were observed.

Comparison of ultra-high performance supercritical fluid chromatography and ultra-high performance liquid chromatography for the separation of spirostanol saponins.

PubMed

Zhu, Ling-Ling; Zhao, Yang; Xu, Yong-Wei; Sun, Qing-Long; Sun, Xin-Guang; Kang, Li-Ping; Yan, Ren-Yi; Zhang, Jie; Liu, Chao; Ma, Bai-Ping

2016-02-20

Spirostanol saponins are important active components of some herb medicines, and their isolation and purification are crucial for the research and development of traditional Chinese medicines. We aimed to compare the separation of spirostanol saponins by ultra-high performance supercritical fluid chromatography (UHPSFC) and ultra-high performance liquid chromatography (UHPLC). Four groups of spirostanol saponins were separated respectively by UHPSFC and UHPLC. After optimization, UHPSFC was performed with a HSS C18 SB column or a Diol column and with methanol as the co-solvent. A BEH C18 column and mobile phase containing water (with 0.1% formic acid) and acetonitrile were used in UHPLC. We found that UHPSFC could be performed automatically and quickly. It is effective in separating the spirostanol saponins which share the same aglycone and vary in sugar chains, and is very sensitive to the number and the position of hydroxyl groups in aglycones. However, the resolution of spirostanol saponins with different aglycones and the same sugar moiety by UHPSFC was not ideal and could be resolved by UHPLC instead. UHPLC is good at differentiating the variation in aglycones, and is influenced by double bonds in aglycones. Therefore, UHPLC and UHPSFC are complementary in separating spirostanol saponins. Considering the naturally produced spirostanol saponins in herb medicines are different both in aglycones and in sugar chains, a better separation can be achieved by combination of UHPLC and UHPSFC. UHPSFC is a powerful technique for improving the resolution when UHPLC cannot resolve a mixture of spirostanol saponins and vice versa. Copyright © 2015 Elsevier B.V. All rights reserved.

Membrane-based technologies for biogas separations.

PubMed

Basu, Subhankar; Khan, Asim L; Cano-Odena, Angels; Liu, Chunqing; Vankelecom, Ivo F J

2010-02-01

Over the past two decades, membrane processes have gained a lot of attention for the separation of gases. They have been found to be very suitable for wide scale applications owing to their reasonable cost, good selectivity and easily engineered modules. This critical review primarily focuses on the various aspects of membrane processes related to the separation of biogas, more in specific CO(2) and H(2)S removal from CH(4) and H(2) streams. Considering the limitations of inorganic materials for membranes, the present review will only focus on work done with polymeric materials. An overview on the performance of commercial membranes and lab-made membranes highlighting the problems associated with their applications will be given first. The development studies carried out to enhance the performance of membranes for gas separation will be discussed in the subsequent section. This review has been broadly divided into three sections (i) performance of commercial polymeric membranes (ii) performance of lab-made polymeric membranes and (iii) performance of mixed matrix membranes (MMMs) for gas separations. It will include structural modifications at polymer level, polymer blending, as well as synthesis of mixed matrix membranes, for which addition of silane-coupling agents and selection of suitable fillers will receive special attention. Apart from an overview of the different membrane materials, the study will also highlight the effects of different operating conditions that eventually decide the performance and longevity of membrane applications in gas separations. The discussion will be largely restricted to the studies carried out on polyimide (PI), cellulose acetate (CA), polysulfone (PSf) and polydimethyl siloxane (PDMS) membranes, as these membrane materials have been most widely used for commercial applications. Finally, the most important strategies that would ensure new commercial applications will be discussed (156 references).

QRS classification and spatial combination for robust heart rate detection in low-quality fetal ECG recordings.

PubMed

Warmerdam, G; Vullings, R; Van Pul, C; Andriessen, P; Oei, S G; Wijn, P

2013-01-01

Non-invasive fetal electrocardiography (ECG) can be used for prolonged monitoring of the fetal heart rate (FHR). However, the signal-to-noise-ratio (SNR) of non-invasive ECG recordings is often insufficient for reliable detection of the FHR. To overcome this problem, source separation techniques can be used to enhance the fetal ECG. This study uses a physiology-based source separation (PBSS) technique that has already been demonstrated to outperform widely used blind source separation techniques. Despite the relatively good performance of PBSS in enhancing the fetal ECG, PBSS is still susceptible to artifacts. In this study an augmented PBSS technique is developed to reduce the influence of artifacts. The performance of the developed method is compared to PBSS on multi-channel non-invasive fetal ECG recordings. Based on this comparison, the developed method is shown to outperform PBSS for the enhancement of the fetal ECG.

Compact CFB: The next generation CFB boiler

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

Utt, J.

1996-12-31

The next generation of compact circulating fluidized bed (CFB) boilers is described in outline form. The following topics are discussed: compact CFB = pyroflow + compact separator; compact CFB; compact separator is a breakthrough design; advantages of CFB; new design with substantial development history; KUHMO: successful demo unit; KUHMO: good performance over load range with low emissions; KOKKOLA: first commercial unit and emissions; KOKKOLA: first commercial unit and emissions; compact CFB installations; next generation CFB boiler; grid nozzle upgrades; cast segmented vortex finders; vortex finder installation; ceramic anchors; pre-cast vertical bullnose; refractory upgrades; and wet gunning.

Separation and quantitation of debrisoquine and 4-hydroxydebrisoquine in human urine by capillary electrophoresis and high-performance liquid chromatography.

PubMed

Cifuentes, A; Valencia, J; Sanz, E; Sánchez, M J; Rodríguez-Delgado, M A

1997-08-22

A comparative study on the use of reversed-phase high-performance liquid chromatography (RP-HPLC) and capillary electrophoresis (CE) for the determination of debrisoquine (D) and its metabolite, 4-hydroxydebrisoquine (4-HD), in human urine is presented. Four different urine pre-treatments are compared for purification of samples prior to their injection in HPLC and CE. The use of a solid-phase extraction with a C18 cartridge provides the best results for the urine sample treatment, with good recoveries, i.e., 94.5% for D and 93.4% for 4-HD, and high reproducibility, i.e., R.S.D. N = 10 values of 1.7% and 1.2%, respectively. Under our separation conditions it is shown that CE is twice as fast and provides slightly better analysis time reproducibility than HPLC for this type of sample. Both the sensitivity and peak area reproducibility are better when HPLC is used. The two techniques show good agreement when employed for determination of phenotypes for hydroxylation, which seems to corroborate the usefulness of CE for this type of study.

Rapid and simple method for the determination of emodin in tartary buckwheat (Fagopyrum tataricum) by high-performance liquid chromatography coupled to a diode array detector.

PubMed

Peng, Lian-Xin; Wang, Jing-Bo; Hu, Li-Xue; Zhao, Jiang-Lin; Xiang, Da-Bing; Zou, Liang; Zhao, Gang

2013-01-30

A simple and rapid method for determining emodin, an active factor presented in tartary buckwheat (Fagopyrum tataricum), by high-performance liquid chromatography coupled to a diode array detector (HPLC-DAD) has been developed. Emodin was separated from an extract of buckwheat on a Kromasil-ODS C(18) (250 mm × 4.6 mm × 5 μm) column. The separation is achieved within 15 min on the ODS column. Emodin can be quantified using an external standard method detecting at 436 nm. Good linearity is obtained with a correlation coefficient exceeding 0.9992. The limit of detection and the limit of quantification are 5.7 and 19 μg/L, respectively. This method shows good reproducibility for the quantification of the emodin with a relative standard deviation value of 4.3%. Under optimized extraction conditions, the recovery of emodin was calculated as >90%. The validated method is successfully applied to quantify the emodin in tartary buckwheat and its products.

Simultaneous quantification of eight bioactive components of Houttuynia cordata and related Saururaceae medicinal plants by on-line high performance liquid chromatography-diode array detector-electrospray mass spectrometry.

PubMed

Meng, Jiang; Leung, Kelvin Sze-Yin; Dong, Xiao-Ping; Zhou, Yi-Sheng; Jiang, Zhi-Hong; Zhao, Zhong-Zhen

2009-12-01

An on-line high performance liquid chromatography (HPLC)-diode array detector (DAD)-electrospray ionization mass spectrometry (ESI-MS) method has been developed to quantify simultaneously eight bioactive chemical components in Houttuynia cordata Thunb and related Saururaceae medicinal plants. Simultaneous separation of these eight compounds was achieved on a C(18) analytical column with gradient elution of acetonitrile and 0.2% acetic acid (v/v) at a flow rate of 0.6 mL/min and being detected at 280 nm. These eight compounds were completely separated within 90 min. Good linear regression relationship (r(2)>0.9978) within test ranges was shown in all calibration curves. Good repeatabilty for the quantification of these eight compounds in H.cordata was also demonstrated in this method, with intra- and inter-day variations less than 3.0%. The method established was successfully applied to quantify eight bioactive compounds in closely related species of H.cordata, which provides a new basis for quality assessment of H.cordata.

Advances in covalent organic frameworks in separation science.

PubMed

Qian, Hai-Long; Yang, Cheng-Xiong; Wang, Wen-Long; Yang, Cheng; Yan, Xiu-Ping

2018-03-23

Covalent organic frameworks (COFs) are a new class of multifunctional crystalline organic polymer constructed with organic monomers via robust covalent bonds. The unique properties such as convenient modification, low densities, large specific surface areas, good stability and permanent porosity make COFs great potential in separation science. This review shows the state-of-the art for the application of COFs and their composites in analytical separation science. COFs and their composites have been explored as promising sorbents for solid phase extraction, potential coatings for solid phase microextraction, and novel stationary phases for gas chromatography, high-performance liquid chromatography and capillary electrochromatography. The prospects of COFs for separation science are also presented, which can offer an outlook and reference for further study on the applications of COFs. Copyright © 2018 Elsevier B.V. All rights reserved.

Computational modeling of electrostatic charge and fields produced by hypervelocity impact

DOE PAGES

Crawford, David A.

2015-05-19

Following prior experimental evidence of electrostatic charge separation, electric and magnetic fields produced by hypervelocity impact, we have developed a model of electrostatic charge separation based on plasma sheath theory and implemented it into the CTH shock physics code. Preliminary assessment of the model shows good qualitative and quantitative agreement between the model and prior experiments at least in the hypervelocity regime for the porous carbonate material tested. The model agrees with the scaling analysis of experimental data performed in the prior work, suggesting that electric charge separation and the resulting electric and magnetic fields can be a substantial effectmore » at larger scales, higher impact velocities, or both.« less

[Advances of poly (ionic liquid) materials in separation science].

PubMed

Liu, Cuicui; Guo, Ting; Su, Rina; Gu, Yuchen; Deng, Qiliang

2015-11-01

Ionic liquids, as novel ionization reagents, possess beneficial characteristics including good solubility, conductivity, thermal stability, biocompatibility, low volatility and non-flammability. Ionic liquids are attracting a mass of attention of analytical chemists. Poly (ionic liquid) materials have common performances of ionic liquids and polymers, and have been successfully applied in separation science area. In this paper, we discuss the interaction mechanisms between the poly(ionic liquid) materials and analytes including hydrophobic/hydrophilic interactions, hydrogen bond, ion exchange, π-π stacking and electrostatic interactions, and summarize the application advances of the poly(ionic liquid) materials in solid phase extraction, chromatographic separation and capillary electrophoresis. At last, we describe the future prospect of poly(ionic liquid) materials.

A novel double loop control model design for chemical unstable processes.

PubMed

Cong, Er-Ding; Hu, Ming-Hui; Tu, Shan-Tung; Xuan, Fu-Zhen; Shao, Hui-He

2014-03-01

In this manuscript, based on Smith predictor control scheme for unstable process in industry, an improved double loop control model is proposed for chemical unstable processes. Inner loop is to stabilize integrating the unstable process and transform the original process to first-order plus pure dead-time dynamic stable process. Outer loop is to enhance the performance of set point response. Disturbance controller is designed to enhance the performance of disturbance response. The improved control system is simple with exact physical meaning. The characteristic equation is easy to realize stabilization. Three controllers are separately design in the improved scheme. It is easy to design each controller and good control performance for the respective closed-loop transfer function separately. The robust stability of the proposed control scheme is analyzed. Finally, case studies illustrate that the improved method can give better system performance than existing design methods. © 2013 ISA Published by ISA All rights reserved.

Fuzzy State Transition and Kalman Filter Applied in Short-Term Traffic Flow Forecasting

PubMed Central

Ming-jun, Deng; Shi-ru, Qu

2015-01-01

Traffic flow is widely recognized as an important parameter for road traffic state forecasting. Fuzzy state transform and Kalman filter (KF) have been applied in this field separately. But the studies show that the former method has good performance on the trend forecasting of traffic state variation but always involves several numerical errors. The latter model is good at numerical forecasting but is deficient in the expression of time hysteretically. This paper proposed an approach that combining fuzzy state transform and KF forecasting model. In considering the advantage of the two models, a weight combination model is proposed. The minimum of the sum forecasting error squared is regarded as a goal in optimizing the combined weight dynamically. Real detection data are used to test the efficiency. Results indicate that the method has a good performance in terms of short-term traffic forecasting. PMID:26779258

Fuzzy State Transition and Kalman Filter Applied in Short-Term Traffic Flow Forecasting.

PubMed

Deng, Ming-jun; Qu, Shi-ru

2015-01-01

Traffic flow is widely recognized as an important parameter for road traffic state forecasting. Fuzzy state transform and Kalman filter (KF) have been applied in this field separately. But the studies show that the former method has good performance on the trend forecasting of traffic state variation but always involves several numerical errors. The latter model is good at numerical forecasting but is deficient in the expression of time hysteretically. This paper proposed an approach that combining fuzzy state transform and KF forecasting model. In considering the advantage of the two models, a weight combination model is proposed. The minimum of the sum forecasting error squared is regarded as a goal in optimizing the combined weight dynamically. Real detection data are used to test the efficiency. Results indicate that the method has a good performance in terms of short-term traffic forecasting.

π-Extended triptycene-based material for capillary gas chromatographic separations.

PubMed

Yang, Yinhui; Wang, Qinsi; Qi, Meiling; Huang, Xuebin

2017-10-02

Triptycene-based materials feature favorable physicochemical properties and unique molecular recognition ability that offer good potential as stationary phases for capillary gas chromatography (GC). Herein, we report the investigation of utilizing a π-extended triptycene material (denoted as TQPP) for GC separations. As a result, the TQPP capillary column exhibited high column efficiency of 4030 plates m -1 and high-resolution performance for a wide range of analytes, especially structural and positional isomers. Interestingly, the TQPP stationary phase showed unique shape selectivity for alkanes isomers and preferential retention for analytes with halogen atoms and H-bonding nature mainly through their halogen-bonding and H-bonding interactions. In addition, the TQPP column had good repeatability and reproducibility with the RSD values of 0.02-0.34% for run-to-run, 0.09-0.80% for day-to-day and 1.4-5.2% for column-to-column, respectively, and favorable thermal stability up to 280 °C. This work demonstrates the promising future of triptycene-based materials as a new class of stationary phases for GC separations. Copyright © 2017 Elsevier B.V. All rights reserved.

Effect of the medium's density on the hydrocyclonic separation of waste plastics with different densities.

PubMed

Fu, Shuangcheng; Fang, Yong; Yuan, Huixin; Tan, Wanjiang; Dong, Yiwen

2017-09-01

Hydrocyclones can be applied to recycle waste plastics with different densities through separating plastics based on their differences in densities. In the process, the medium density is one of key parameters and the value of the medium's density is not just the average of the density of two kinds of plastics separated. Based on the force analysis and establishing the equation of motion of particles in the hydrocyclone, a formula to calculate the optimum separation medium density has been deduced. This value of the medium's density is a function of various parameters including the diameter, density, radial position and tangential velocity of particles, and viscosity of the medium. Tests on the separation performance of the hydrocyclone has been conducted with PET and PVC particles. The theoretical result appeared to be in good agreement with experimental results. Copyright © 2017 Elsevier Ltd. All rights reserved.

Constructing Free Standing Metal Organic Framework MIL-53 Membrane Based on Anodized Aluminum Oxide Precursor

PubMed Central

Zhang, Yunlu; Gao, Qiuming; Lin, Zhi; Zhang, Tao; Xu, Jiandong; Tan, Yanli; Tian, Weiqian; Jiang, Lei

2014-01-01

Metal organic framework (MOF) materials have attracted great attention due to their well-ordered and controllable pores possessing of prominent potentials for gas molecule sorption and separation performances. Organizing the MOF crystals to a continuous membrane with a certain scale will better exhibit their prominent potentials. Reports in recent years concentrate on well grown MOF membranes on specific substrates. Free standing MOF membranes could have more important applications since they are independent from the substrates. However, the method to prepare such a membrane has been a great challenge because good mechanical properties and stabilities are highly required. Here, we demonstrate a novel and facile technique for preparing the free standing membrane with a size as large as centimeter scale. The substrate we use proved itself not only a good skeleton but also an excellent precursor to fulfill the reaction. This kind of membrane owns a strong mechanical strength, based on the fact that it is much thinner than the composite membranes grown on substrates and it could exhibit good property of gas separation. PMID:24821299

Analysis of two-equation turbulence models for recirculating flows

NASA Technical Reports Server (NTRS)

Thangam, S.

1991-01-01

The two-equation kappa-epsilon model is used to analyze turbulent separated flow past a backward-facing step. It is shown that if the model constraints are modified to be consistent with the accepted energy decay rate for isotropic turbulence, the dominant features of the flow field, namely the size of the separation bubble and the streamwise component of the mean velocity, can be accurately predicted. In addition, except in the vicinity of the step, very good predictions for the turbulent shear stress, the wall pressure, and the wall shear stress are obtained. The model is also shown to provide good predictions for the turbulence intensity in the region downstream of the reattachment point. Estimated long time growth rates for the turbulent kinetic energy and dissipation rate of homogeneous shear flow are utilized to develop an optimal set of constants for the two equation kappa-epsilon model. The physical implications of the model performance are also discussed.

Pigment dispersion syndrome associated with intraocular lens implantation: a new surgical technique.

PubMed

Canut Jordana, M Isabel; Pérez Formigó, Daniel; Abreu González, Rodrigo; Nadal Reus, Jeroni

2010-11-11

We report the case of a myopic patient who, after intraocular lens transplant in the posterior chamber, suffered elevated intraocular pressure due to pigment dispersion, with recurrent episodes of blurred vision. The patient was treated with a new surgical technique that can avoid potential iridolenticular contact. Complete ophthalmologic examination and optical coherence tomography (OCT) of the anterior segment were performed. Contact between the pigmentary epithelium and the iris with an intraocular lens was revealed by utrasound biomicroscopy and OCT. In this case, Nd:YAG laser iridotomy and laser iridoplasty were not effective for iridolenticular separation and control of the pigment dispersion. We propose a new technique: stitches on the surface of the iris to obtain good iridolenticular separation and good intraocular pressure control. Stitches on the iris surface should be considered as optional therapy in pigmentary glaucoma secondary to intraocular lens implantation. This surgical technique can avoid potential iridolenticular contacts more definitively.

Morphology-Patterned Anisotropic Wetting Surface for Fluid Control and Gas-Liquid Separation in Microfluidics.

PubMed

Wang, Shuli; Yu, Nianzuo; Wang, Tieqiang; Ge, Peng; Ye, Shunsheng; Xue, Peihong; Liu, Wendong; Shen, Huaizhong; Zhang, Junhu; Yang, Bai

2016-05-25

This article shows morphology-patterned stripes as a new platform for directing flow guidance of the fluid in microfluidic devices. Anisotropic (even unidirectional) spreading behavior due to anisotropic wetting of the underlying surface is observed after integrating morphology-patterned stripes with a Y-shaped microchannel. The anisotropic wetting flow of the fluid is influenced by the applied pressure, dimensions of the patterns, including the period and depth of the structure, and size of the channels. Fluids with different surface tensions show different flowing anisotropy in our microdevice. Moreover, the morphology-patterned surfaces could be used as a microvalve, and gas-water separation in the microchannel was realized using the unidirectional flow of water. Therefore, benefiting from their good performance and simple fabrication process, morphology-patterned surfaces are good candidates to be applied in controlling the fluid behavior in microfluidics.

[Simultaneous determination of four common nonprotein nitrogen substances in urine by high performance liquid chromatography].

PubMed

Ma, Yuhua; Huang, Dongqun; Zhang, Rui; Xu, Shiru; Feng, Shun

2013-11-01

A high performance liquid chromatographic (HPLC) method was proposed to simultaneously determine four common nonprotein nitrogen substances, including creatine (Cr), creatinine (Cn), uric acid (Ua) and pseudouridine (Pu) in urine. After proteins being removed by acetone precipitation method, freeze drying and redissolving, the urine samples were analyzed by HPLC. Chromatographic separation was performed on a Waters RP18 Column (150 mm x 4.60 mm, 3.5 microm) in gradient elution mode using 10.0 mmol/L KH2PO4 solution (pH 4.78) and acetonitrile as mobile phases at a flow rate of 0.8 mL/min. The samples were detected at 220 nm. Rapid separation was achieved within 7 min. Under the optimized conditions, good linearities of four common nonprotein nitrogen substances were obtained in the range of 0.1-250 mg/L. The detection limits were 9.31 (Cr), 26.19 (Cn), 4.70 (Ua), an 6.30 (Pu) microg/L and the recoveries were in the range of 81%-111% with the relative standar deviations of 0.23%-2.78% (n = 3). The results demonstrate that this method is simple, rapid and accurate with good reproducibility, and can provide early diagnosis and preliminary judgment for type 2 diabetes mellitus (T2DM) patients with renal damage.

Modified Separator Performing Dual Physical/Chemical Roles to Inhibit Polysulfide Shuttle Resulting in Ultrastable Li-S Batteries.

PubMed

Abbas, Syed Ali; Ding, Jiang; Wu, Sheng Hui; Fang, Jason; Boopathi, Karunakara Moorthy; Mohapatra, Anisha; Lee, Li Wei; Wang, Pen-Cheng; Chang, Chien-Cheng; Chu, Chih Wei

2017-12-26

In this paper we describe a modified (AEG/CH) coated separator for Li-S batteries in which the shuttling phenomenon of the lithium polysulfides is restrained through two types of interactions: activated expanded graphite (AEG) flakes interacted physically with the lithium polysulfides, while chitosan (CH), used to bind the AEG flakes on the separator, interacted chemically through its abundance of amino and hydroxyl functional groups. Moreover, the AEG flakes facilitated ionic and electronic transfer during the redox reaction. Live H-cell discharging experiments revealed that the modified separator was effective at curbing polysulfide shuttling; moreover, X-ray photoelectron spectroscopy analysis of the cycled separator confirmed the presence of lithium polysulfides in the AEG/CH matrix. Using this dual functional interaction approach, the lifetime of the pure sulfur-based cathode was extended to 3000 cycles at 1C-rate (1C = 1670 mA/g), decreasing the decay rate to 0.021% per cycle, a value that is among the best reported to date. A flexible battery based on this modified separator exhibited stable performance and could turn on multiple light-emitting diodes. Such modified membranes with good mechanical strength, high electronic conductivity, and anti-self-discharging shield appear to be a scalable solution for future high-energy battery systems.

Rapid separation and identification of phenolics in crude red grape skin extracts by high performance liquid chromatography coupled to diode array detection and tandem mass spectrometry.

PubMed

Ji, Mei; Li, Chen; Li, Qiang

2015-10-02

A rapid and efficient method was established for the simultaneous determination of structures and configurations for 45 phenolics isolated from crude red grape skin extracts without extensive sample preparation. Separation and compound assignments were achieved using high performance liquid chromatography coupled to diode array detection and tandem mass spectrometry (HPLC-DAD-MS(2)). A Poroshell 120 EC-C18 (100mm×3.0mm, 2.7μm) column was employed to separate the phenolics, which were eluted using a gradient of acetonitrile and water acidified with 0.2% formic acid. Phenolics were identified by comparison of their UV-vis spectra, mass spectra and MS(2) data with those in the literature. Using this procedure, five compounds were detected for the first time in Vitis amurensis. Good separation of most phenolics was achieved in 26min. The methods described here can be used for the characterization of phenolics in a variety of grapes and grape products. Copyright © 2015 Elsevier B.V. All rights reserved.

A F-doped tree-like nanofiber structural poly-m-phenyleneisophthalamide separator for high-performance lithium-sulfur batteries

NASA Astrophysics Data System (ADS)

Deng, Nanping; Wang, Yan; Yan, Jing; Ju, Jingge; Li, Zongjie; Fan, Lanlan; Zhao, Huijuan; Kang, Weimin; Cheng, Bowen

2017-09-01

In this study, F-doped tree-like nanofiber structural poly-m-phenyleneisophthalamide (PMIA) membranes are prepared via one-step electrospinning approach and their application performance as separators for lithium-sulfur batteries are discussed. The F-doped PMIA membrane can be regarded as matrix to form gel polymer electrolyte. The F doping endows the PMIA membranes with extraordinary high electrolyte uptake, excellent ability of preserving the liquid electrolyte and forceful chemisorption to polysulfides. And the tree-like structure effectively blocks polysulfides by the physical confinement. The lithium-sulfur cell with the F-doped PMIA separator exhibits high first-cycle discharge capacity of 1222.5 mAh g-1 and excellent cycling stability with good capacity retention of 745.7 mAh g-1 and coulombic efficiency of 97.97% after 800 cycles. The remarkable performance can be ascribed to the suppressed shuttle effects through both the physical trapping of polysulfides by the gel polymer electrolyte based on matrix with F-doped PMIA membrane and the tree-like structure in a working cell.

Supercapacitor Operating At 200 Degrees Celsius

PubMed Central

Borges, Raquel S.; Reddy, Arava Leela Mohana; Rodrigues, Marco-Tulio F.; Gullapalli, Hemtej; Balakrishnan, Kaushik; Silva, Glaura G.; Ajayan, Pulickel M.

2013-01-01

The operating temperatures of current electrochemical energy storage devices are limited due to electrolyte degradation and separator instability at higher temperatures. Here we demonstrate that a tailored mixture of materials can facilitate operation of supercapacitors at record temperatures, as high as 200°C. Composite electrolyte/separator structures made from naturally occurring clay and room temperature ionic liquids, with graphitic carbon electrodes, show stable supercapacitor performance at 200°C with good cyclic stability. Free standing films of such high temperature composite electrolyte systems can become versatile functional membranes in several high temperature energy conversion and storage applications. PMID:23999206

Construction of a hydrazone-linked chiral covalent organic framework-silica composite as the stationary phase for high performance liquid chromatography.

PubMed

Zhang, Kai; Cai, Song-Liang; Yan, Yi-Lun; He, Zi-Hao; Lin, Hui-Mei; Huang, Xiao-Ling; Zheng, Sheng-Run; Fan, Jun; Zhang, Wei-Guang

2017-10-13

Covalent organic frameworks (COFs), as an emerging class of crystalline porous organic polymers, have great potential for applications in chromatographic separation owning to their fascinating crystalline structures and outstanding properties. However, development of COF materials as novel stationary phases in high performance liquid chromatography (HPLC) is just in its infancy. Herein, we report the design and construction of a new hydrazone-linked chiral COF, termed BtaMth COF, from a chiral hydrazide building block (Mth) and present a one-pot synthetic method for the fabrication of BtaMth@SiO 2 composite for HPLC separation of isomers. The as-synthesized BtaMth chiral COF displays good crystallinity, high porosity, as well as excellent chemical stability. Meanwhile, the fabricated HPLC column by using BtaMth@SiO 2 composite as the new stationary phase exhibits high resolution performances for the separation of positional isomers including nitrotoluene and nitrochlorobenzene, as well as cis-trans isomers including beta-cypermethrin and metconazole. Additionally, some effects such as the composition of the mobile phase and column temperature for HPLC separations on the BtaMth@SiO 2 packed column also have been studied in detail. The successful applications indicate the great potentials of hydrazone-linked chiral COF-silica composite as novel stationary phase for the efficient HPLC separation. Copyright © 2017 Elsevier B.V. All rights reserved.

High-throughput separation of cells by dielectrophoresis enhanced with 3D gradient AC electric field.

PubMed

Tada, Shigeru; Hayashi, Masako; Eguchi, Masanori; Tsukamoto, Akira

2017-11-01

We propose a novel, high-performance dielectrophoretic (DEP) cell-separation flow chamber with a parallel-plate channel geometry. The flow chamber, consisting of a planar electrode on the top and an interdigitated-pair electrode array at the bottom, was developed to facilitate the separation of cells by creating a nonuniform AC electric field throughout the volume of the flow chamber. The operation and performance of the device were evaluated using live and dead human epithermal breast (MCF10A) cells. The separation dynamics of the cell suspension in the flow chamber was also investigated by numerically simulating the trajectories of individual cells. A theoretical model to describe the dynamic cell behavior under the action of DEP, including dipole-dipole interparticle, viscous, and gravitational forces, was developed. The results demonstrated that the live cells traveling through the flow chamber congregated into sites where the electric field gradient was minimal, in the middle of the flow stream slightly above the centerlines of the grounded electrodes at the bottom. Meanwhile, the dead cells were trapped on the edges of the high-voltage electrodes at the bottom. Cells were thus successfully separated with a remarkably high separation ratio (∼98%) at the appropriately tuned field frequency and applied voltage. The numerically predicted behavior and spatial distribution of the cells during separation also showed good agreement with those observed experimentally.

Separating live from dead longleaf pine seeds: good and bad news

Treesearch

James P. Barnett; R. Kasten Dumroese

2006-01-01

Of all southern pine seeds, longleaf pine (Pinus palutris Mill.) are the most difficult to collect, process, treat, and store while maintaining good seed quality. As a result, interest in techniques for separating filled dead from live longleaf pine seeds has developed. The good news is that new technologies are becoming available to evaluate seed...

Experimental, Theoretical, and Computational Investigation of Separated Nozzle Flows

NASA Technical Reports Server (NTRS)

Hunter, Craig A.

2004-01-01

A detailed experimental, theoretical, and computational study of separated nozzle flows has been conducted. Experimental testing was performed at the NASA Langley 16-Foot Transonic Tunnel Complex. As part of a comprehensive static performance investigation, force, moment, and pressure measurements were made and schlieren flow visualization was obtained for a sub-scale, non-axisymmetric, two-dimensional, convergent- divergent nozzle. In addition, two-dimensional numerical simulations were run using the computational fluid dynamics code PAB3D with two-equation turbulence closure and algebraic Reynolds stress modeling. For reference, experimental and computational results were compared with theoretical predictions based on one-dimensional gas dynamics and an approximate integral momentum boundary layer method. Experimental results from this study indicate that off-design overexpanded nozzle flow was dominated by shock induced boundary layer separation, which was divided into two distinct flow regimes; three- dimensional separation with partial reattachment, and fully detached two-dimensional separation. The test nozzle was observed to go through a marked transition in passing from one regime to the other. In all cases, separation provided a significant increase in static thrust efficiency compared to the ideal prediction. Results indicate that with controlled separation, the entire overexpanded range of nozzle performance would be within 10% of the peak thrust efficiency. By offering savings in weight and complexity over a conventional mechanical exhaust system, this may allow a fixed geometry nozzle to cover an entire flight envelope. The computational simulation was in excellent agreement with experimental data over most of the test range, and did a good job of modeling internal flow and thrust performance. An exception occurred at low nozzle pressure ratios, where the two-dimensional computational model was inconsistent with the three-dimensional separation observed in the experiment. In general, the computation captured the physics of the shock boundary layer interaction and shock induced boundary layer separation in the nozzle, though there were some differences in shock structure compared to experiment. Though minor, these differences could be important for studies involving flow control or thrust vectoring of separated nozzles. Combined with other observations, this indicates that more detailed, three-dimensional computational modeling needs to be conducted to more realistically simulate shock-separated nozzle flows.

Determination of CMPO using HPLC -UV

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

Gracy Elias; Gary S. Groenewold; Bruce J. Mincher

Octyl(phenyl)-N,N-diisobutylcarbamoylmethylphosphine oxide (CMPO) is an extractant proposed for selective separation of radionuclide metals from used nuclear fuel solutions using solvent extraction. Radiolysis reactions can degrade CMPO and reduce separation performance and hence methods for measuring concentration of CMPO and identifying degradation products are needed. A novel high performance liquid chromatography (HPLC) method employing ultraviolet detection (UV) was developed to detect and quantitate CMPO in dodecane. Some radiolysis products in gamma and alpha irradiated CMPO solutions were identified using HPLC/electrospray ionization-mass spectrometry (ESI-MS). Validation data indicated that the HPLC-UV method for CMPO determination provided good linearity, sensitivity, procedure accuracy and systemmore » precision. CMPO-nitric acid complexes were also identified, that account for the apparent loss of CMPO in acidic environment, independent of irradiation.« less

Simultaneous quantitative determination of six active components in traditional Chinese medicinal preparation Cerebralcare Granule® by RP-HPLC coupled with diode array detection for quality control.

PubMed

Wang, Xiang-yang; Ma, Xiao-hui; Li, Wei; Chu, Yang; Guo, Jia-hua; Zhou, Shui-ping; Zhu, Yong-hong

2014-09-01

A simple, accurate and reliable method for the simultaneous separation and determination of six active components (protocatechuic acid, chlorogenic acid, caffeic acid, paeoniflorin, ferulic acid and rosmarinic acid) in traditional Chinese medicinal preparation Cerebralcare Granule(®) (CG) was developed using reverse-phase high-performance liquid chromatography coupled with diode array detector detection. The chromatographic separation was performed on a Hypersil GOLD C18 column with aqueous formic acid (0.1%, v/v) and acetonitrile as mobile phase at a flow rate of 0.2 ml/min at 30 °C. Because of the different UV characteristics of these components, change detection wavelength method was used for quantitative analysis. All of the analytes showed good linearity (r > 0.9992). The established method showed good precision and relative standard deviations (%) for intra-day and inter-day variations of 0.15-1.81 and 0.11-1.98%, respectively. The validated method was successfully applied to the simultaneously determination of six active components in CG from different batches. © The Author [2013]. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

On Some Separated Algorithms for Separable Nonlinear Least Squares Problems.

PubMed

Gan, Min; Chen, C L Philip; Chen, Guang-Yong; Chen, Long

2017-10-03

For a class of nonlinear least squares problems, it is usually very beneficial to separate the variables into a linear and a nonlinear part and take full advantage of reliable linear least squares techniques. Consequently, the original problem is turned into a reduced problem which involves only nonlinear parameters. We consider in this paper four separated algorithms for such problems. The first one is the variable projection (VP) algorithm with full Jacobian matrix of Golub and Pereyra. The second and third ones are VP algorithms with simplified Jacobian matrices proposed by Kaufman and Ruano et al. respectively. The fourth one only uses the gradient of the reduced problem. Monte Carlo experiments are conducted to compare the performance of these four algorithms. From the results of the experiments, we find that: 1) the simplified Jacobian proposed by Ruano et al. is not a good choice for the VP algorithm; moreover, it may render the algorithm hard to converge; 2) the fourth algorithm perform moderately among these four algorithms; 3) the VP algorithm with the full Jacobian matrix perform more stable than that of the VP algorithm with Kuafman's simplified one; and 4) the combination of VP algorithm and Levenberg-Marquardt method is more effective than the combination of VP algorithm and Gauss-Newton method.

Separation of Intercepted Multi-Radar Signals Based on Parameterized Time-Frequency Analysis

NASA Astrophysics Data System (ADS)

Lu, W. L.; Xie, J. W.; Wang, H. M.; Sheng, C.

2016-09-01

Modern radars use complex waveforms to obtain high detection performance and low probabilities of interception and identification. Signals intercepted from multiple radars overlap considerably in both the time and frequency domains and are difficult to separate with primary time parameters. Time-frequency analysis (TFA), as a key signal-processing tool, can provide better insight into the signal than conventional methods. In particular, among the various types of TFA, parameterized time-frequency analysis (PTFA) has shown great potential to investigate the time-frequency features of such non-stationary signals. In this paper, we propose a procedure for PTFA to separate overlapped radar signals; it includes five steps: initiation, parameterized time-frequency analysis, demodulating the signal of interest, adaptive filtering and recovering the signal. The effectiveness of the method was verified with simulated data and an intercepted radar signal received in a microwave laboratory. The results show that the proposed method has good performance and has potential in electronic reconnaissance applications, such as electronic intelligence, electronic warfare support measures, and radar warning.

Observation of the quantum paradox of separation of a single photon from one of its properties

NASA Astrophysics Data System (ADS)

Ashby, James M.; Schwarz, Peter D.; Schlosshauer, Maximilian

2016-07-01

We report an experimental realization of the quantum paradox of the separation of a single photon from one of its properties (the so-called "quantum Cheshire cat"). We use a modified Sagnac interferometer with displaced paths to produce appropriately pre- and postselected states of heralded single photons. Weak measurements of photon presence and circular polarization are performed in each arm of the interferometer by introducing weak absorbers and small polarization rotations and analyzing changes in the postselected signal. The absorber is found to have an appreciable effect only in one arm of the interferometer, while the polarization rotation significantly affects the signal only when performed in the other arm. We carry out both sequential and simultaneous weak measurements and find good agreement between measured and predicted weak values. In the language of Aharonov et al. and in the sense of the ensemble averages described by weak values, the experiment establishes the separation of a particle from one its properties during the passage through the interferometer.

Unresolved Galaxy Classifier for ESA/Gaia mission: Support Vector Machines approach

NASA Astrophysics Data System (ADS)

Bellas-Velidis, Ioannis; Kontizas, Mary; Dapergolas, Anastasios; Livanou, Evdokia; Kontizas, Evangelos; Karampelas, Antonios

A software package Unresolved Galaxy Classifier (UGC) is being developed for the ground-based pipeline of ESA's Gaia mission. It aims to provide an automated taxonomic classification and specific parameters estimation analyzing Gaia BP/RP instrument low-dispersion spectra of unresolved galaxies. The UGC algorithm is based on a supervised learning technique, the Support Vector Machines (SVM). The software is implemented in Java as two separate modules. An offline learning module provides functions for SVM-models training. Once trained, the set of models can be repeatedly applied to unknown galaxy spectra by the pipeline's application module. A library of galaxy models synthetic spectra, simulated for the BP/RP instrument, is used to train and test the modules. Science tests show a very good classification performance of UGC and relatively good regression performance, except for some of the parameters. Possible approaches to improve the performance are discussed.

Partitioning sparse matrices with eigenvectors of graphs

NASA Technical Reports Server (NTRS)

Pothen, Alex; Simon, Horst D.; Liou, Kang-Pu

1990-01-01

The problem of computing a small vertex separator in a graph arises in the context of computing a good ordering for the parallel factorization of sparse, symmetric matrices. An algebraic approach for computing vertex separators is considered in this paper. It is shown that lower bounds on separator sizes can be obtained in terms of the eigenvalues of the Laplacian matrix associated with a graph. The Laplacian eigenvectors of grid graphs can be computed from Kronecker products involving the eigenvectors of path graphs, and these eigenvectors can be used to compute good separators in grid graphs. A heuristic algorithm is designed to compute a vertex separator in a general graph by first computing an edge separator in the graph from an eigenvector of the Laplacian matrix, and then using a maximum matching in a subgraph to compute the vertex separator. Results on the quality of the separators computed by the spectral algorithm are presented, and these are compared with separators obtained from other algorithms for computing separators. Finally, the time required to compute the Laplacian eigenvector is reported, and the accuracy with which the eigenvector must be computed to obtain good separators is considered. The spectral algorithm has the advantage that it can be implemented on a medium-size multiprocessor in a straightforward manner.

Varieties of semantic cognition revealed through simultaneous decomposition of intrinsic brain connectivity and behaviour.

PubMed

Vatansever, Deniz; Bzdok, Danilo; Wang, Hao-Ting; Mollo, Giovanna; Sormaz, Mladen; Murphy, Charlotte; Karapanagiotidis, Theodoros; Smallwood, Jonathan; Jefferies, Elizabeth

2017-09-01

Contemporary theories assume that semantic cognition emerges from a neural architecture in which different component processes are combined to produce aspects of conceptual thought and behaviour. In addition to the state-level, momentary variation in brain connectivity, individuals may also differ in their propensity to generate particular configurations of such components, and these trait-level differences may relate to individual differences in semantic cognition. We tested this view by exploring how variation in intrinsic brain functional connectivity between semantic nodes in fMRI was related to performance on a battery of semantic tasks in 154 healthy participants. Through simultaneous decomposition of brain functional connectivity and semantic task performance, we identified distinct components of semantic cognition at rest. In a subsequent validation step, these data-driven components demonstrated explanatory power for neural responses in an fMRI-based semantic localiser task and variation in self-generated thoughts during the resting-state scan. Our findings showed that good performance on harder semantic tasks was associated with relative segregation at rest between frontal brain regions implicated in controlled semantic retrieval and the default mode network. Poor performance on easier tasks was linked to greater coupling between the same frontal regions and the anterior temporal lobe; a pattern associated with deliberate, verbal thematic thoughts at rest. We also identified components that related to qualities of semantic cognition: relatively good performance on pictorial semantic tasks was associated with greater separation of angular gyrus from frontal control sites and greater integration with posterior cingulate and anterior temporal cortex. In contrast, good speech production was linked to the separation of angular gyrus, posterior cingulate and temporal lobe regions. Together these data show that quantitative and qualitative variation in semantic cognition across individuals emerges from variations in the interaction of nodes within distinct functional brain networks. Copyright © 2017 Elsevier Inc. All rights reserved.

Ultrathin self-assembled anionic polymer membranes for superfast size-selective separation

NASA Astrophysics Data System (ADS)

Deng, Chao; Zhang, Qiu Gen; Han, Guang Lu; Gong, Yi; Zhu, Ai Mei; Liu, Qing Lin

2013-10-01

Nanoporous membranes with superior separation performance have become more crucial with increasing concerns in functional nanomaterials. Here novel ultrahigh permeable nanoporous membranes have been fabricated on macroporous supports by self-assembly of anionic polymer on copper hydroxide nanostrand templates in organic solution. This facile approach has a great potential for the fabrication of ultrathin anionic polymer membranes as a general method. The as-fabricated self-assembled membranes have a mean pore size of 5-12 nm and an adjustable thickness as low as 85 nm. They allow superfast permeation of water, and exhibit excellent size-selective separation properties and good fouling resistance for negatively-charged solutes during filtration. The 85 nm thick membrane has an ultrahigh water flux (3306 l m-2 h-1 bar-1) that is an order of magnitude larger than commercial membranes, and can highly efficiently separate 5 and 15 nm gold nanoparticles from their mixtures. The newly developed nanoporous membranes have a wide application in separation and purification of biomacromolecules and nanoparticles.Nanoporous membranes with superior separation performance have become more crucial with increasing concerns in functional nanomaterials. Here novel ultrahigh permeable nanoporous membranes have been fabricated on macroporous supports by self-assembly of anionic polymer on copper hydroxide nanostrand templates in organic solution. This facile approach has a great potential for the fabrication of ultrathin anionic polymer membranes as a general method. The as-fabricated self-assembled membranes have a mean pore size of 5-12 nm and an adjustable thickness as low as 85 nm. They allow superfast permeation of water, and exhibit excellent size-selective separation properties and good fouling resistance for negatively-charged solutes during filtration. The 85 nm thick membrane has an ultrahigh water flux (3306 l m-2 h-1 bar-1) that is an order of magnitude larger than commercial membranes, and can highly efficiently separate 5 and 15 nm gold nanoparticles from their mixtures. The newly developed nanoporous membranes have a wide application in separation and purification of biomacromolecules and nanoparticles. Electronic supplementary information (ESI) available: Synthesis and characterization of SPEK-C; effect of the sulfonation degree on membrane formation; structure and properties of the self-assembled membranes; separation of cyt.c by the self-assembled membranes; size-selective separation of gold nanoparticles by the self-assembled membranes; comparison with commercial flat sheet ultrafiltration membranes. See DOI: 10.1039/c3nr03362g

Reliability of ultrasound grading traditional score and new global OMERACT-EULAR score system (GLOESS): results from an inter- and intra-reading exercise by rheumatologists.

PubMed

Ventura-Ríos, Lucio; Hernández-Díaz, Cristina; Ferrusquia-Toríz, Diana; Cruz-Arenas, Esteban; Rodríguez-Henríquez, Pedro; Alvarez Del Castillo, Ana Laura; Campaña-Parra, Alfredo; Canul, Efrén; Guerrero Yeo, Gerardo; Mendoza-Ruiz, Juan Jorge; Pérez Cristóbal, Mario; Sicsik, Sandra; Silva Luna, Karina

2017-12-01

This study aims to test the reliability of ultrasound to graduate synovitis in static and video images, evaluating separately grayscale and power Doppler (PD), and combined. Thirteen trained rheumatologist ultrasonographers participated in two separate rounds reading 42 images, 15 static and 27 videos, of the 7-joint count [wrist, 2nd and 3rd metacarpophalangeal (MCP), 2nd and 3rd interphalangeal (IPP), 2nd and 5th metatarsophalangeal (MTP) joints]. The images were from six patients with rheumatoid arthritis, performed by one ultrasonographer. Synovitis definition was according to OMERACT. Scoring system in grayscale, PD separately, and combined (GLOESS-Global OMERACT-EULAR Score System) were reviewed before exercise. Reliability intra- and inter-reading was calculated with Cohen's kappa weighted, according to Landis and Koch. Kappa values for inter-reading were good to excellent. The minor kappa was for GLOESS in static images, and the highest was for the same scoring in videos (k 0.59 and 0.85, respectively). Excellent values were obtained for static PD in 5th MTP joint and for PD video in 2nd MTP joint. Results for GLOESS in general were good to moderate. Poor agreement was observed in 3rd MCP and 3rd IPP in all kinds of images. Intra-reading agreement were greater in grayscale and GLOESS in static images than in videos (k 0.86 vs. 0.77 and k 0.86 vs. 0.71, respectively), but PD was greater in videos than in static images (k 1.0 vs. 0.79). The reliability of the synovitis scoring through static images and videos is in general good to moderate when using grayscale and PD separately or combined.

Hyperspectral data discrimination methods

NASA Astrophysics Data System (ADS)

Casasent, David P.; Chen, Xuewen

2000-12-01

Hyperspectral data provides spectral response information that provides detailed chemical, moisture, and other description of constituent parts of an item. These new sensor data are useful in USDA product inspection. However, such data introduce problems such as the curse of dimensionality, the need to reduce the number of features used to accommodate realistic small training set sizes, and the need to employ discriminatory features and still achieve good generalization (comparable training and test set performance). Several two-step methods are compared to a new and preferable single-step spectral decomposition algorithm. Initial results on hyperspectral data for good/bad almonds and for good/bad (aflatoxin infested) corn kernels are presented. The hyperspectral application addressed differs greatly from prior USDA work (PLS) in which the level of a specific channel constituent in food was estimated. A validation set (separate from the test set) is used in selecting algorithm parameters. Threshold parameters are varied to select the best Pc operating point. Initial results show that nonlinear features yield improved performance.

Grace DAKASEP alkaline battery separator

NASA Technical Reports Server (NTRS)

Giovannoni, R. T.; Lundquist, J. T.; Choi, W. M.

1987-01-01

The Grace DAKASEP separator was originally developed as a wicking layer for nickel-zinc alkaline batteries. The DAKASEP is a filled non-woven separator which is flexible and heat sealable. Through modification of formulation and processing variables, products with a variety of properties can be produced. Variations of DAKASEP were tested in Ni-H2, Ni-Zn, Ni-Cd, and primary alkaline batteries with good results. The properties of DAKASEP which are optimized for Hg-Zn primary batteries are shown in tabular form. This separator has high tensile strength, 12 micron average pore size, relatively low porosity at 46-48 percent, and consequently moderately high resistivity. Versions were produced with greater than 70 percent porosity and resistivities in 33 wt percent KOH as low as 3 ohm cm. Performance data for Hg-Zn E-1 size cells containing DAKASEP with the properties shown in tabular form, are more reproducible than data obtained with a competitive polypropylene non-woven separator. In addition, utilization of active material is in general considerably improved.

Pneumatic Microvalve-Based Hydrodynamic Sample Injection for High-Throughput, Quantitative Zone Electrophoresis in Capillaries

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

Kelly, Ryan T.; Wang, Chenchen; Rausch, Sarah J.

2014-07-01

A hybrid microchip/capillary CE system was developed to allow unbiased and lossless sample loading and high throughput repeated injections. This new hybrid CE system consists of a polydimethylsiloxane (PDMS) microchip sample injector featuring a pneumatic microvalve that separates a sample introduction channel from a short sample loading channel and a fused silica capillary separation column that connects seamlessly to the sample loading channel. The sample introduction channel is pressurized such that when the pneumatic microvalve opens briefly, a variable-volume sample plug is introduced into the loading channel. A high voltage for CE separation is continuously applied across the loading channelmore » and the fused silica capillary separation column. Analytes are rapidly separated in the fused silica capillary with high resolution. High sensitivity MS detection after CE separation is accomplished via a sheathless CE/ESI-MS interface. The performance evaluation of the complete CE/ESI-MS platform demonstrated that reproducible sample injection with well controlled sample plug volumes could be achieved by using the PDMS microchip injector. The absence of band broadening from microchip to capillary indicated a minimum dead volume at the junction. The capabilities of the new CE/ESI-MS platform in performing high throughput and quantitative sample analyses were demonstrated by the repeated sample injection without interrupting an ongoing separation and a good linear dependence of the total analyte ion abundance on the sample plug volume using a mixture of peptide standards. The separation efficiency of the new platform was also evaluated systematically at different sample injection times, flow rates and CE separation voltages.« less

Separation of swine wastewater into different concentration fractions and its contribution to combined anaerobic-aerobic process.

PubMed

Yang, Di; Deng, Liangwei; Zheng, Dan; Wang, Lan; Liu, Yi

2016-03-01

There are two problems associated with treatment of swine wastewater, low efficiency of anaerobic digestion during winter and poor performance for aerobic treatment of digested effluent. A strategy employing unbalanced distributions of the pollutant mass and wastewater volumes in anaerobic and aerobic units was proposed. To accomplish this, swine wastewater was separated into high content liquid (HCL) and low content liquid (LCL). Three separation ratios of HCL to LCL (v/v), 1:9 (S1), 2:8 (S2), and 3:7 (S3), were evaluated. Anaerobically digestion of the HCL accounted for only 10%, 20% and 30% of the total volume of raw wastewater, but produced 63.38%, 73.79% and 76.61% of the total methane output for S1, S2 and S3, respectively. The mixed liquid of digested effluents of HCL and LCL were treated aerobically using sequencing batch reactors. S2 generated the best performance, with removal efficiencies of 96.98% for COD, 98.95% for NH3-N, 91.69% for TN and 74.71% for TP. The results obtained for S1 were not as good as those for S2, but were better than those for S3. Based on methane output from the anaerobic unit and pollutants removal in the aerobic unit, S2 was the most suitable system for the treatment of swine wastewater. Additionally, the anaerobic digestion efficiency of S2 was 282% higher than that of previous techniques employing balanced distribution. Taken together, these findings indicate that unbalanced distribution could improve the efficiency of the anaerobic unit remarkably, while ensuring good performance of the aerobic unit. Copyright © 2015. Published by Elsevier Ltd.

The ethics of separating conjoined twins: two arguments against.

PubMed

Kallberg, Luke

2018-02-01

I argue that the separation of conjoined twins in infancy or early childhood is unethical (rare exceptions aside). Cases may be divided into three types: both twins suffer from lethal abnormalities, only one twin has a lethal abnormality, or neither twin does. In the first kind of case, there is no reason to separate, since both twins will die regardless of treatment. In the third kind of case, I argue that separation at an early age is unethical because the twins are likely to achieve an irreplaceably good quality of life-the goods of conjoinment-that separation takes away. Evaluation of this possibility requires maturation past early childhood. Regarding the second type, I point out that with conceivable but unrecorded exceptions, these cases will consistently involve sacrifice separation. I present an argument that sacrifice separation is unethical, but in some cases a moral dilemma may exist in which separation and refraining from separation are both unethical. Perhaps in such cases a decision can be made on non-moral grounds; however, the possibility of such a decision serves not to mitigate but to underscore the fact that the separation is unethical. My conclusion, which applies to all three types of cases, is that it is unethical to separate conjoined twins before their developing personalities give some reliable indication as to whether they desire separation and whether they will achieve those goods of conjoinment.

Separation of Be and Al for AMS using single-step column chromatography

NASA Astrophysics Data System (ADS)

Binnie, Steven A.; Dunai, Tibor J.; Voronina, Elena; Goral, Tomasz; Heinze, Stefan; Dewald, Alfred

2015-10-01

With the aim of simplifying AMS target preparation procedures for TCN measurements we tested a new extraction chromatography approach which couples an anion exchange resin (WBEC) to a chelating resin (Beryllium resin) to separate Be and Al from dissolved quartz samples. Results show that WBEC-Beryllium resin stacks can be used to provide high purity Be and Al separations using a combination of hydrochloric/oxalic and nitric acid elutions. 10Be and 26Al concentrations from quartz samples prepared using more standard procedures are compared with results from replicate samples prepared using the coupled WBEC-Beryllium resin approach and show good agreement. The new column procedure is performed in a single step, reducing sample preparation times relative to more traditional methods of TCN target production.

Novel Chromatographic Methods for Simultaneous Quantification of Fish and Wheat Germ Oils Mixture in Pharmaceutical Dosage Forms.

PubMed

El-Yazbi, Amira F; El-Hawiet, Amr

2017-05-01

Two simple, direct and environment-friendly chromatographic methods, high-performance liquid chromatography (HPLC) and high-performance thin layer chromatographic (HPTLC), were developed for the determination of a binary mixture of fish oil (FO) and wheat germ oil (WGO), for the first time, in their pharmaceutical dosage forms with no need for any sample pretreatment. The HPLC separation was carried out using C-18 stationary phase with mobile phase of 15% formic acid (pH 6), methanol and acetonitrile through gradient-elution, 1.5 mL min-1 flow-rate and detection at 215 nm for FO and 280 nm for WGO. HPTLC separation was carried out on silica-coated plates using diethyl ether-petroleum ether (0.5:9.5, v/v) as mobile phase. Detection was at 215 nm for FO and 240 nm for WGO. Regression analysis showed good linear relationship with r > 0.999 in the concentration-ranges of 0.2-2 mg mL-1 and 2.5-20 μg band-1 for WGO by HPLC and HPTLC methods, respectively, and 0.4-10 mg mL-1 and 25-200 μg band-1 for FO by HPLC and HPTLC methods, respectively. The methods were validated, showed good analytical performance and were successfully applied for the analysis of pharmaceutical formulations and synthetic mixtures of the analytes with good recoveries. Therefore, the two methods could be conveniently adopted for routine analysis of similar products in quality control laboratories of pharmaceutical industries especially that simultaneous determination of FO-WGO mixture has not been reported previously. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

A simple way to prepare Pd/Fe₃O₄/polypyrrole hollow capsules and their applications in catalysis.

PubMed

Yao, Tongjie; Zuo, Quan; Wang, Hao; Wu, Jie; Xin, Baifu; Cui, Fang; Cui, Tieyu

2015-07-15

Preparation of catalysts with good catalytic activity and high stability, together with magnetic separation property, in a simple way is highly desirable. In this paper, we reported a novel strategy to construct magnetic recyclable hollow capsules with Pd and Fe3O4 nanoparticles embedded in polypyrrole (PPy) shell via only two steps: first, synthesization of Pd nanoparticles, preparation of Fe3O4 nanoparticles, and formation of PPy shell were finished in one-step on the surface of polystyrene (PS) nanospheres; then, the PS core was selectively removed by tetrahydrofuran. The Pd/Fe3O4/PPy hollow capsules exhibited good catalytic property in reduction of 4-nitrophenol with NaBH4 as reducing agent, and the reaction rate constants were calculated through pseudo-first-order reaction equation. Due to incorporation of Fe3O4 nanoparticles, the catalysts could be quickly separated from the reaction solution by magnet and reused without obvious catalytic loss. Besides catalytic property and reusability, their stability was also examined by HNO3 etching experiment. Compared with bare Pd and Fe3O4 nanoparticles, the stability of both Pd and Fe3O4 nanoparticles in hollow capsules was largely improved owing to the protection of PPy shell. The good catalytic performance, ease of separation, high stability and especially a simple preparation procedure, made Pd/Fe3O4/PPy hollow capsules highly promising candidates for diverse applications. Copyright © 2015 Elsevier Inc. All rights reserved.

A rapid method for the sequential separation of polonium, plutonium, americium and uranium in drinking water.

PubMed

Lemons, B; Khaing, H; Ward, A; Thakur, P

2018-06-01

A new sequential separation method for the determination of polonium and actinides (Pu, Am and U) in drinking water samples has been developed that can be used for emergency response or routine water analyses. For the first time, the application of TEVA chromatography column in the sequential separation of polonium and plutonium has been studied. This method utilizes a rapid Fe +3 co-precipitation step to remove matrix interferences, followed by plutonium oxidation state adjustment to Pu 4+ and an incubation period of ~ 1 h at 50-60 °C to allow Po 2+ to oxidize to Po 4+ . The polonium and plutonium were then separated on a TEVA column, while separation of americium from uranium was performed on a TRU column. After separation, polonium was micro-precipitated with copper sulfide (CuS), while actinides were micro co-precipitated using neodymium fluoride (NdF 3 ) for counting by the alpha spectrometry. The method is simple, robust and can be performed quickly with excellent removal of interferences, high chemical recovery and very good alpha peak resolution. The efficiency and reliability of the procedures were tested by using spiked samples. The effect of several transition metals (Cu 2+ , Pb 2+ , Fe 3+ , Fe 2+ , and Ni 2+ ) on the performance of this method were also assessed to evaluate the potential matrix effects. Studies indicate that presence of up to 25 mg of these cations in the samples had no adverse effect on the recovery or the resolution of polonium alpha peaks. Copyright © 2018 Elsevier Ltd. All rights reserved.

Mixed cellulose ester filter as a separator for air-diffusion cathode microbial fuel cells.

PubMed

Wang, Zejie; Lim, Bongsu

2017-04-01

Separator is important to prevent bio-contamination of the catalyst layer of air-diffusion cathode microbial fuel cells (MFCs). Mixed cellulose ester filter (MCEF) was examined as a separator for an air-cathode MFC in the present study. The MCEF-MFC produced a maximum power density of 780.7 ± 18.7 mW/m 2 , which was comparable to 770.9 ± 35.9 mW/m 2 of MFC with Nafion membrane (NFM) as a separator. Long-term examination demonstrated a more stable performance of the MCEF-MFC than NFM-MFC. After 25 cycles, the maximum voltage of the MCEF-MFC decreased by only 1.3% from 425.1 ± 4.3 mV (initial 5 cycles) to 419.5 ± 2.3 mV (last 5 cycles). However, it was decreased by 9.1% from 424.8 ± 5.7 to 386 ± 2.5 mV for the NFM-MFC. The coulombic efficiency (CE) of the MCEF-MFC did not change (from 3.11 ± 0.09% to 3.13 ± 0.02%), while it decreased by 9.12% from 3.18 ± 0.04% to 2.89 ± 0.02% for the NFM-MFC. The MCEF separator was with less biofouling than the NFM separator over 60 days' operation, which might be the reason for the more table long-term performance of the MCEF-MFC. The results demonstrated that MCEF was feasible as a separator to set up good-performing and cost-effective air-diffusion cathode MFC.

The influence of perceived stress and musculoskeletal pain on work performance and work ability in Swedish health care workers.

PubMed

Lindegård, A; Larsman, P; Hadzibajramovic, E; Ahlborg, G

2014-05-01

To evaluate the influence of perceived stress and musculoskeletal ache/pain, separately and in combination, at baseline, on self-rated work ability and work performance at two-year follow-up. Survey data were collected with a 2-year interval. Health care workers participating at both waves were included. Inclusion criteria were good self-reported work ability and unchanged self-rated work performance at baseline, resulting in 770 participants; 617 women and 153 men. Musculoskeletal pain was assessed using the question "How often do you experience pain in joints and muscles, including the neck and low back?", perceived stress with a modified version of a single item from the QPS-Nordic questionnaire, work performance by the question "Have your work performance changed during the preceding 12 months?" and work ability by a single item from the work ability index. Associations between baseline data and the two outcomes at follow-up were analysed by means of the log binomial model and expressed as risk ratios (RR) with 95% confidence intervals (CI). A combination of frequent musculoskeletal pain and perceived stress constituted the highest risk for reporting decreased work performance (RR 1.7; CI 1.28-2.32) and reduced work ability (RR 1.7; CI 1.27-2.30) at follow-up. Separately, frequent pain, but not stress, was clearly associated with both outcomes. The results imply that proactive workplace interventions in order to maintain high work performance and good work ability should include measures to promote musculoskeletal well-being for the employees and measures, both individual and organizational, to minimize the risk of persistent stress reactions.

Stratification and segregation features of pulverized electronic waste in flowing film concentration.

PubMed

Vidyadhar, A; Chalavadi, G; Das, A

2013-03-30

Gravity separation of metals from plastics in pulverized e-waste using flowing film concentration in a shaking table was investigated. Over 51% rejection of plastics in a single stage operation was achieved under optimum conditions. The shaking table was shown to be suitable for processing ground PCBs. Pulverized e-waste containing 22% metals was enriched to around 40% metals in a single pass. Statistical models for the mass yield of metal-rich stream and its grade were developed by design of experiments. Optimization was carried out to maximize the mass yield at a target product grade and preferred operating regimes were established. Experiments were designed to prevent metal loss and over 95% recovery values were obtained under all conditions. Settling distances of metals and plastics were computed and shown to be good indicators of separation performance. Particle morphology and stratification in the troughs in between the riffles were shown to influence the separation significantly. Water flow-assisted motion of the plastics was captured and its role in determining the effectiveness of separation was described. The efficacy of tabling was well established for treating ground PCBs. The wet process was shown to be environment friendly and sustainable. It is also relatively cheap and has good potential for industrial application. However, rigorous cost estimates will be required before commercial application. Copyright © 2013 Elsevier Ltd. All rights reserved.

Development of novel separation techniques for biological samples in capillary electrophoresis

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

Chang, Huan -Tsung

1994-07-27

This dissertation includes three different topics: general introduction of capillary electrophoresis (CE); gradient in CE and CE in biological separations; and capillary gel electrophoresis (CGE) for DNA separation. Factors such as temperature, viscosity, pH, and the surface of capillary walls affecting the separation performance are demonstrated. A pH gradient between 3.0 and 5.2 is useful to improve the resolution among eight different organic acids. A flow gradient due to the change in the concentration of surfactant, which is able to coat to the capillary wall to change the flow rate and its direction, is also shown as a good waymore » to improve the resolution for organic compounds. A temperature gradient caused by joule heat is shown by voltage programming to enhance the resolution and shorten the separation time for several phenolic compounds. The author also shows that self-regulating dynamic control of electroosmotic flow in CE by simply running separation in different concentrations of surfactant has less matrix effect on the separation performance. One of the most important demonstrations in this dissertation is that the author proposes on-column reaction which gives several advantages including the use of a small amount of sample, low risk of contamination, and time saving and kinetic features. The author uses this idea with laser induced fluorescence (LIF) as a detection mode to detect an on-column digestion of sub-ng of protein. This technique also is applied to single cell analysis in the group.« less

Detailed Investigation of Separation Performance of a MMM for Removal of Higher Hydrocarbons under Varying Operating Conditions

PubMed Central

Mushardt, Heike; Müller, Marcus; Shishatskiy, Sergey; Wind, Jan; Brinkmann, Torsten

2016-01-01

Mixed-matrix membranes (MMMs) are promising candidates to improve the competitiveness of membrane technology against energy-intensive conventional technologies. In this work, MMM composed of poly(octylmethylsiloxane) (POMS) and activated carbon (AC) were investigated with respect to separation of higher hydrocarbons (C3+) from permanent gas streams. Membranes were prepared as thin film composite membranes on a technical scale and characterized via scanning electron microscopy (SEM) and permeation measurements with binary mixtures of n-C4H10/CH4 under varying operating conditions (feed and permeate pressure, temperature, feed gas composition) to study the influence on separation performance. SEM showed good contact and absence of defects. Lower permeances but higher selectivities were found for MMM compared to pure POMS membrane. Best results were obtained at high average fugacity and activity of n-C4H10 with the highest selectivity estimated to be 36.4 at n-C4H10 permeance of 12 mN3/(m2·h·bar). Results were complemented by permeation of a multi-component mixture resembling a natural gas application, demonstrating the superior performance of MMM. PMID:26927194

Evaluation of a liquid chromatography method for compound-specific δ13C analysis of plant carbohydrates in alkaline media.

PubMed

Rinne, Katja T; Saurer, Matthias; Streit, Kathrin; Siegwolf, Rolf T W

2012-09-30

Isotope analysis of carbohydrates is important for improved understanding of plant carbon metabolism and plant physiological response to the environment. High-performance liquid chromatography/isotope ratio mass spectrometry (HPLC/IRMS) for direct compound-specific δ(13)C measurements of soluble carbohydrates has recently been developed, but the still challenging sample preparation and the fact that no single method is capable of separating all compounds of interest hinder its wide-spread application. Here we tested in detail a chromatography method in alkaline media. We examined the most suitable chromatographic conditions for HPLC/IRMS analysis of carbohydrates in aqueous conifer needle extracts using a CarboPac PA20 anion-exchange column with NaOH eluent, paying specific attention to compound yields, carbon isotope fractionation processes and the reproducibility of the method. Furthermore, we adapted and calibrated sample preparation methods for HPLC/IRMS analysis. OnGuard II cartridges were used for sample purification. Good peak separation and highly linear and reproducible concentration and δ(13)C measurements were obtained. The alkaline eluent was observed to induce isomerization of hexoses, detected as reduced yields and (13)C fractionation of the affected compounds. A reproducible pre-purification method providing ~100% yield for the carbohydrate compounds of interest was calibrated. The good level of peak separation obtained in this study is reflected in the good precision and linearity of concentration and δ(13)C results. The data provided crucial information on the behaviour of sugars in LC analysis with alkaline media. The observations highlight the importance for the application of compound-matched standard solution for the detection and correction of instrumental biases in concentration and δ(13)C analysis performed under identical chromatographic conditions. The calibrated pre-purification method is well suited for studies with complex matrices that disable the use of a spiked internal standard for the detection of procedural losses. Copyright © 2012 John Wiley & Sons, Ltd.

DETERMINATION OF VENLAFAXINE, VILAZODONE AND THEIR MAIN ACTIVE METABOLITES IN HUMAN SERUM BY HPLC-DAD AND HPLC-MS.

PubMed

Petruczynik, Anna; Wroblewski, Karol; Szultka-Mlynska, Malgorzata; Buszewsk, Boguslaw; Karakula-Juchnowicz, Hanna; Gajewski, Jacek; Morylowska-Topolska, Justyna; Waksmundzka-Hajnosi, Monika

2017-05-01

A high performance liquid chromatography (HPLC) method for simultaneous analysis of venlafaxine and its major metabolite 0-desmethylvenlafaxine and vilazodone and its methabolite M10 have been devel- oped and validated. Chromatography was performed on the Phenyl-Hexyl column with mobile phase containing methanol, acetate buffer at pH 3.5 and diethylamine. The application of stationary phase with 7r-7c moieties and mobile phase containing diethylamine as silanol blocker lets to obtain double protection against silanols and thus very high theoretical plate numbers were obtained. The good separation selectivity, good peaks' symmetry and very high systems efficiency for all investigated compounds were obtained in applied chromatographic system. The method is very efficient and suitable for the analysis of investigated drugs and their metabolites in human serum for patients' pharmacotherapy control.

The Nike-Black Brant V development program

NASA Technical Reports Server (NTRS)

Sevier, H.; Payne, B.; Ott, R.; Montag, W.

1976-01-01

The Nike-Black Brant V represents a combined U.S.-Canadian program to achieve a 40 percent increase in apogee performance over that of the unboosted BBV, with minimum component modification and no meaningful increase in flight environment levels. The process of achieving these objectives is described, in particular optimization of sustainer coast period and roll history, and the techniques used to ensure good stage separation. Details of the structural test program and subsequent successful vehicle proving flight are provided. Basic performance data are preented, with an indication of the further potential offered by Terrier boost.

Molecular-level characterization of crude oil compounds combining reversed-phase high-performance liquid chromatography with off-line high-resolution mass spectrometry

USGS Publications Warehouse

Sim, Arum; Cho, Yunju; Kim, Daae; Witt, Matthias; Birdwell, Justin E.; Kim, Byung Ju; Kim, Sunghwan

2014-01-01

A reversed-phase separation technique was developed in a previous study (Loegel et al., 2012) and successfully applied to the de-asphalted fraction of crude oil. However, to the best of our knowledge, the molecular-level characterization of oil fractions obtained by reversed-phase high-performance liquid chromatography (HPLC) coupled with high-resolution mass spectrometry (MS) has not yet been reported. A detailed characterization of the oil fractions prepared by reversed-phase HPLC was performed in this study. HPLC fractionation was carried out on conventional crude oil and an oil shale pyrolysate. The analyses of the fractions showed that the carbon number of alkyl chains and the double bond equivalent (DBE) value were the major factors determining elution order. The compounds with larger DBE (presumably more condensed aromatic structures) and smaller carbon number (presumably compounds with short side chains) were eluted earlier but those compounds with lower DBE values (presumably less aromatic structures) and higher carbon number (presumably compounds with longer alkyl chains) eluted later in the chromatograms. This separation behavior is in good agreement with that expected from the principles of reversed-phase separation. The data presented in this study show that reversed-phase chromatography is effective in separating crude oil compounds and can be combined with ultrahigh-resolution MS data to better understand natural oils and oil shale pyrolysates.

Dual redox catalysts for oxygen reduction and evolution reactions: towards a redox flow Li-O2 battery.

PubMed

Zhu, Yun Guang; Jia, Chuankun; Yang, Jing; Pan, Feng; Huang, Qizhao; Wang, Qing

2015-06-11

A redox flow lithium-oxygen battery (RFLOB) by using soluble redox catalysts with good performance was demonstrated for large-scale energy storage. The new device enables the reversible formation and decomposition of Li2O2 via redox targeting reactions in a gas diffusion tank, spatially separated from the electrode, which obviates the passivation and pore clogging of the cathode.

Development and Validation of a HPTLC Method for Simultaneous Estimation of L-Glutamic Acid and γ-Aminobutyric Acid in Mice Brain

PubMed Central

Sancheti, J. S.; Shaikh, M. F.; Khatwani, P. F.; Kulkarni, Savita R.; Sathaye, Sadhana

2013-01-01

A new robust, simple and economic high performance thin layer chromatographic method was developed for simultaneous estimation of L-glutamic acid and γ-amino butyric acid in brain homogenate. The high performance thin layer chromatographic separation of these amino acid was achieved using n-butanol:glacial acetic acid:water (22:3:5 v/v/v) as mobile phase and ninhydrin as a derivatising agent. Quantitation of the method was achieved by densitometric method at 550 nm over the concentration range of 10-100 ng/spot. This method showed good separation of amino acids in the brain homogenate with Rf value of L-glutamic acid and γ-amino butyric acid as 21.67±0.58 and 33.67±0.58, respectively. The limit of detection and limit of quantification for L-glutamic acid was found to be 10 and 20 ng and for γ-amino butyric acid it was 4 and 10 ng, respectively. The method was also validated in terms of accuracy, precision and repeatability. The developed method was found to be precise and accurate with good reproducibility and shows promising applicability for studying pathological status of disease and therapeutic significance of drug treatment. PMID:24591747

Development and Validation of a HPTLC Method for Simultaneous Estimation of L-Glutamic Acid and γ-Aminobutyric Acid in Mice Brain.

PubMed

Sancheti, J S; Shaikh, M F; Khatwani, P F; Kulkarni, Savita R; Sathaye, Sadhana

2013-11-01

A new robust, simple and economic high performance thin layer chromatographic method was developed for simultaneous estimation of L-glutamic acid and γ-amino butyric acid in brain homogenate. The high performance thin layer chromatographic separation of these amino acid was achieved using n-butanol:glacial acetic acid:water (22:3:5 v/v/v) as mobile phase and ninhydrin as a derivatising agent. Quantitation of the method was achieved by densitometric method at 550 nm over the concentration range of 10-100 ng/spot. This method showed good separation of amino acids in the brain homogenate with Rf value of L-glutamic acid and γ-amino butyric acid as 21.67±0.58 and 33.67±0.58, respectively. The limit of detection and limit of quantification for L-glutamic acid was found to be 10 and 20 ng and for γ-amino butyric acid it was 4 and 10 ng, respectively. The method was also validated in terms of accuracy, precision and repeatability. The developed method was found to be precise and accurate with good reproducibility and shows promising applicability for studying pathological status of disease and therapeutic significance of drug treatment.

Carbon molecular sieve membranes on porous composite tubular supports for high performance gas separations

DOE PAGES

Lee, Pyung -Soo; Bhave, Ramesh R.; Nam, Seung -Eun; ...

2016-01-11

Thin carbon molecular sieve membranes (<500 nm) were fabricated inside of long geometry (9 inch) of stainless steel tubes with all welded construction. Alumina intermediate layer on porous stainless steel tube support was used to reduce effective support pore size and to provide a more uniform surface roughness. Novolac phenolic resin solution was then coated on the inside of porous stainless steel tube by slip casting while their viscosities were controlled from 5 centipoises to 30 centipoises. Carbonization was carried out at 700 °C in which thermal stress was minimized and high quality carbon films were prepared. The highest separationmore » performance characteristics were obtained using 20 cP phenolic resin solutions. The fabricated CMSM showed good separation factor for He/N 2 462, CO 2/N 2 97, and O 2/N 2 15.4. As the viscosity of polymer precursor solution was reduced from 20 cP to 15 cP, gas permeance values almost doubled with somewhat lower separation factor He/N 2 156, CO 2/N 2 88, and O 2/N 2 7.7.« less

[Determination of penicillin intermediate and three penicillins in milk by high performance capillary electrophoresis].

PubMed

Tian, Chunqiu; Tan, Huarong; Gao, Liping; Shen, Huqin; Qi, Kezong

2011-11-01

A high performance capillary electrophoresis (HPCE) method was developed for the simultaneous determination of penicillin intermediate and penicillins in milk, including 6-amino-penicillanic acid (6-APA), penicillin G (PEN), ampicillin (AMP) and amoxicillin (AMO). The main parameters including the ion concentration and pH value of running buffer, separation voltage and column temperature were optimized systematically by orthogonal test. The four penicillins (PENs) were baseline separated within 4.5 min with the running buffer of 40 mmol/L potassium dihydrogen phosphate-20 mmol/L borax solution (pH 7.8), separation voltage of 28 kV and column temperature of 30 degrees C. The calibration curves showed good linearity in the range of 1.56 - 100 mg/L, and the correlation coefficients (r2) were between 0.9979 and 0.9998. The average recoveries at three spiked levels were in the range of 84.91% - 96.72% with acceptable relative standard deviations (RSDs) of 1.11% - 9.11%. The method is simple, fast, accurate and suitable for the determination of penicillins in real samples.

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.

A hybrid algorithm for the segmentation of books in libraries

NASA Astrophysics Data System (ADS)

Hu, Zilong; Tang, Jinshan; Lei, Liang

2016-05-01

This paper proposes an algorithm for book segmentation based on bookshelves images. The algorithm can be separated into three parts. The first part is pre-processing, aiming at eliminating or decreasing the effect of image noise and illumination conditions. The second part is near-horizontal line detection based on Canny edge detector, and separating a bookshelves image into multiple sub-images so that each sub-image contains an individual shelf. The last part is book segmentation. In each shelf image, near-vertical line is detected, and obtained lines are used for book segmentation. The proposed algorithm was tested with the bookshelf images taken from OPIE library in MTU, and the experimental results demonstrate good performance.

Molecular simulation investigation into the performance of Cu-BTC metal-organic frameworks for carbon dioxide-methane separations.

PubMed

Gutiérrez-Sevillano, Juan José; Caro-Pérez, Alejandro; Dubbeldam, David; Calero, Sofía

2011-12-07

We report a molecular simulation study for Cu-BTC metal-organic frameworks as carbon dioxide-methane separation devices. For this study we have computed adsorption and diffusion of methane and carbon dioxide in the structure, both as pure components and mixtures over the full range of bulk gas compositions. From the single component isotherms, mixture adsorption is predicted using the ideal adsorbed solution theory. These predictions are in very good agreement with our computed mixture isotherms and with previously reported data. Adsorption and diffusion selectivities and preferential sitings are also discussed with the aim to provide new molecular level information for all studied systems.

20 CFR Appendix B to Part 625 - Standard for Claim Determinations-Separation Information

Code of Federal Regulations, 2013 CFR

2013-04-01

... separation was voluntary, and the reason does not constitute good cause,” rather than merely the phrase... mailed or hand-delivered. (b) An explanation of any circumstances (such as nonworkdays, good cause, etc... used to supplement the employer-information requirements. Such a program should stress the availability...

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

Wei, Xiaoliang; Duan, Wentao; Huang, Jinhua

Nonaqueous redox flow batteries are promising in pursuit of high-energy storage systems owing to the broad voltage window, but currently are facing key challenges such as poor cycling stability and lack of suitable membranes. Here we report a new nonaqueous all-organic flow chemistry that demonstrates an outstanding cell cycling stability primarily because of high chemical persistency of the organic radical redox species and their good compatibility with the supporting electrolyte. A feasibility study shows that Daramic® and Celgard® porous separators can lead to high cell conductivity in flow cells thus producing remarkable cell efficiency and material utilization even at highmore » current operations. This result suggests that the thickness and pore size are the key performance-determining factors for porous separators. With the greatly improved flow cell performance, this new flow system largely addresses the above mentioned challenges and the findings may greatly expedite the development of durable nonaqueous flow batteries.« less

Chromatographic fingerprint analysis of yohimbe bark and related dietary supplements using UHPLC/UV/MS.

PubMed

Sun, Jianghao; Chen, Pei

2012-03-05

A practical ultra high-performance liquid chromatography (UHPLC) method was developed for fingerprint analysis of and determination of yohimbine in yohimbe barks and related dietary supplements. Good separation was achieved using a Waters Acquity BEH C(18) column with gradient elution using 0.1% (v/v) aqueous ammonium hydroxide and 0.1% ammonium hydroxide in methanol as the mobile phases. The study is the first reported chromatographic method that separates corynanthine from yohimbine in yohimbe bark extract. The chromatographic fingerprint analysis was applied to the analysis of 18 yohimbe commercial dietary supplement samples. Quantitation of yohimbine, the traditional method for analysis of yohimbe barks, were also performed to evaluate the results of the fingerprint analysis. Wide variability was observed in fingerprints and yohimbine content among yohimbe dietary supplement samples. For most of the dietary supplements, the yohimbine content was not consistent with the label claims. Copyright © 2011. Published by Elsevier B.V.

Viscous investigation of a flapping foil propulsor

NASA Astrophysics Data System (ADS)

Posri, Attapol; Phoemsapthawee, Surasak; Thaweewat, Nonthipat

2018-01-01

Inspired by how fishes propel themselves, a flapping-foil device is invented as an alternative propulsion system for ships and boats. The performance of such propulsor has been formerly investigated using a potential flow code. The simulation results have shown that the device has high propulsive efficiency over a wide range of operation. However, the potential flow gives good results only when flow separation is not present. In case of high flapping frequency, the flow separation can occur over a short instant due to fluid viscosity and high angle of attack. This may cause a reduction of propulsive efficiency. A commercial CFD code based on Lattice Boltzmann Method, XFlow, is then employed in order to investigate the viscous effect over the propulsive performance of the flapping foil. The viscous results agree well with the potential flow results, confirming the high efficiency of the propulsor. As expected, viscous results show lower efficiency in high flapping frequency zone.

High efficiency protein separation with organosilane assembled silica coated magnetic nanoparticles

NASA Astrophysics Data System (ADS)

Chang, Jeong Ho; Kang, Ki Ho; Choi, Jinsub; Jeong, Young Keun

2008-10-01

This work describes the development of high efficiency protein separation with functionalized organosilanes on the surface of silica coated magnetic nanoparticles. The magnetic nanoparticles were synthesized with average particle size of 9 nm and silica coated magnetic nanoparticles were obtained by controlling the coating thicknesses on magnetic nanoparticles. The silica coating thickness could be uniformly sized with a diameter of 10-40 nm by a sol-gel approach. The surface modification was performed with four kinds of functionalized organosilanes such as carboxyl, aldehyde, amine, and thiol groups. The protein separation work with organosilane assembled silica coated magnetic nanoparticles was achieved for model proteins such as bovine serum albumin (BSA) and lysozyme (LSZ) at different pH conditions. Among the various functionalities, the thiol group showed good separation efficiency due to the change of electrostatic interactions and protein conformational structure. The adsorption efficiency of BSA and LSZ was up to 74% and 90% corresponding pH 4.65 and pH 11.

One-step assembly of Fe(III)-CMC chelate hydrogel onto nanoneedle-like CuO@Cu membrane with superhydrophilicity for oil-water separation

NASA Astrophysics Data System (ADS)

Dai, Jiangdong; Chang, Zhongshuai; Xie, Atian; Zhang, Ruilong; Tian, Sujun; Ge, Wenna; Yan, Yongsheng; Li, Chunxiang; Xu, Wei; Shao, Rong

2018-05-01

The research of superhydrophilic interface is developing rapidly, but the preparations of superhydrophilic surfaces through simple methods are still challenging. Herein, we reported a facile, rapid and environmentally-friendly approach for preparing a novel superhydrophilic and underwater superoleophobic membrane via the thermal oxidation of Cu mesh and one-step coordinated assembly of Fe(III)-CMC chelate hydrogel. Superhydrophilicity was attributed to the hydrophilicity of Fe(III)-CMC chelate hydrogel and nanoneedle-like rough structure of CuO@Cu membrane. The membrane was used to separate a variety of oil/water mixtures and exhibited excellent separation performance. Moreover, the membrane exhibited the excellent durability and superior stability against corrosion conditions. We envision that the Fe(III)-CMC@CuO@Cu membrane with good underwater superoleophobicity could provide a candidate not only for oil/water separation but also many other potential applications such as underwater oil manipulation, self-clean, and bio-adhesion control.

Towards Acid-Tolerated Ethanol Dehydration: Chitosan-Based Mixed Matrix Membranes Containing Cyano-Bridged Coordination Polymer Nanoparticles.

PubMed

Wu, C-W; Kang, Chao-Hsiang; Lin, Yi-Feng; Tung, Kuo-Lun; Deng, Yu-Heng; Ahamad, Tansir; Alshehri, Saad M; Suzuki, Norihiro; Yamauchi, Yusuke

2016-04-01

Prussian blue (PB) nanoparticles, one of many cyano-bridged coordination polymers, are successfully incorporated into chitosan (CS) polymer to prepare PB/CS mixed matrix membranes (MMMs). The PB nanoparticles are uniformly distributed in the MMMs without the collapse of the original PB structure. As-prepared PB/CS MMMs are used for ethanol dehydration at 25 °C in the pervaporation process. The effect of loading PB in CS matrix on pervaporation performance is carefully investigated. The PB/CS membrane with 30 wt% PB loading shows the best performance with a permeate flux of 614 g. m-2 . h-1 and a separation factor of 1472. The pervaporation using our PB/CS membranes exhibits outstanding performance in comparison with the previously reported CS-based membranes and MMMs. Furthermore, the addition of PB allows PB/CS MMMs to be tolerant of acidic environment. The present work demonstrates good pervaporation performance of PB/CS MMMs for the separation of an ethanol/water (90:10 in wt%) solution. Our new system provides an opportunity for dehydration of bioethanol in the future.

A facile method to prepare dual-functional membrane for efficient oil removal and in situ reversible mercury ions adsorption from wastewater

NASA Astrophysics Data System (ADS)

Zhang, Qingdong; Liu, Na; Cao, Yingze; Zhang, Weifeng; Wei, Yen; Feng, Lin; Jiang, Lei

2018-03-01

In this work, a novel thiol covered polyamide (nylon 66) microfiltration membrane was fabricated by combining mussel-inspired chemistry and coupling reaction, which owns excellent dual-function that can simultaneously remove oil from water efficiently and adsorb the mercury ions contained in the wastewater reversibly. Such membrane exhibited high oil/water separation efficiency, outstanding mercury adsorption ability, and good stability. Moreover, it can be regenerated in nitric acid solution, and maintain its good adsorption performance. The as-prepared membrane showed great potentials for water purification to reduce the heavy metal ion pollution and complicated industrial oily wastewater and living wastewater.

NASA Lewis Helps Company With New Single-Engine Business Turbojet

NASA Technical Reports Server (NTRS)

1998-01-01

Century Aerospace Corporation, a small company in Albuquerque, New Mexico, is developing a six-seat aircraft powered by a single turbofan engine for general aviation. The company had completed a preliminary design of the jet but needed analyses and testing to proceed with detailed design and subsequent fabrication of a prototype aircraft. NASA Lewis Research Center used computational fluid dynamics (CFD) analyses to ferret out areas of excessive curvature in the inlet where separation might occur. A preliminary look at the results indicated very good inlet performance; and additional calculations, performed with vortex generators installed in the inlet, led to even better results. When it was initially determined that the airflow distortion pattern at the compressor face fell outside of the limits set by the engine manufacturer, the Lewis team studied possible solutions, selected the best, and provided recommendations. CFD results for the inlet system were so good that wind tunnel tests were unnecessary.

Three-dimensional numerical investigation of the separation process in a vortex tube at different operating conditions

NASA Astrophysics Data System (ADS)

Rafiee, Seyed Ehsan; Sadeghiazad, M. M.

2016-06-01

Air separators provide safe, clean, and appropriate air flow to engines and are widely used in vehicles with large engines such as ships and submarines. In this operational study, the separation process inside a Ranque-Hilsch vortex tube cleaning (cooling) system is investigated to analyze the impact of the operating gas type on the vortex tube performance; the operating gases used are air, nitrogen, oxygen, carbon dioxide and nitrogen dioxide. The computational fluid dynamic model used is equipped with a three-dimensional structure, and the steady-state condition is applied during computations. The standard k-ɛ turbulence model is employed to resolve nonlinear flow equations, and various key parameters, such as hot and cold exhaust thermal drops, and power separation rates, are described numerically. The results show that nitrogen dioxide creates the greatest separation power out of all gases tested, and the numerical results are validated by good agreement with available experimental data. In addition, a comparison is made between the use of two different boundary conditions, the pressure-far-field and the pressure-outlet, when analyzing complex turbulent flows inside the air separators. Results present a comprehensive and practical solution for use in future numerical studies.

FRP/steel composite damage acoustic emission monitoring and analysis

NASA Astrophysics Data System (ADS)

Li, Dongsheng; Chen, Zhi

2015-04-01

FRP is a new material with good mechanical properties, such as high strength of extension, low density, good corrosion resistance and anti-fatigue. FRP and steel composite has gotten a wide range of applications in civil engineering because of its good performance. As the FRP/steel composite get more and more widely used, the monitor of its damage is also getting more important. To monitor this composite, acoustic emission (AE) is a good choice. In this study, we prepare four identical specimens to conduct our test. During the testing process, the AE character parameters and mechanics properties were obtained. Damaged properties of FRP/steel composite were analyzed through acoustic emission (AE) signals. By the growing trend of AE accumulated energy, the severity of the damage made on FRP/steel composite was estimated. The AE sentry function has been successfully used to study damage progression and fracture emerge release rate of composite laminates. This technique combines the cumulative AE energy with strain energy of the material rather than analyzes the AE information and mechanical separately.

10 CFR 2.317 - Separate hearings; consolidation of proceedings.

Code of Federal Regulations, 2010 CFR

2010-01-01

.... (a) Separate hearings. On motion by the parties or upon request of the presiding officer for good... it is found that the action will be conducive to the proper dispatch of its business and to the ends...) Consolidation of proceedings. On motion and for good cause shown or on its own initiative, the Commission or the...

Integrated protein analysis platform based on column switch recycling size exclusion chromatography, microenzymatic reactor and microRPLC-ESI-MS/MS.

PubMed

Yuan, Huiming; Zhou, Yuan; Zhang, Lihua; Liang, Zhen; Zhang, Yukui

2009-10-30

An integrated platform with the combination of proteins and peptides separation was established via the unit of on-line proteins digestion, by which proteins were in sequence separated by column switch recycling size exclusion chromatography (csrSEC), on-line digested by an immobilized trypsin microreactor, trapped and desalted by two parallel C8 precolumns, separated by microRPLC with the linear gradient of organic modifier concentration, and identified by ESI-MS/MS. A 6-protein mixture, with Mr ranging from 10 kDa to 80 kDa, was used to evaluate the performance of the integrated platform, and all proteins were identified with sequence coverage over 5.67%. Our experimental results demonstrate that such an integrated platform is of advantages such as good time compatibility, high peak capacity, and facile automation, which might be a promising approach for proteome study.

Layer-by-layer self-assembled graphene oxide/silica microsphere composites as stationary phase for high performance liquid chromatography.

PubMed

Liang, Xiaojing; Liu, Shujuan; Song, Xinwang; Zhu, Yangwen; Jiang, Shengxiang

2012-11-21

Graphene oxide (GO) has been layer-by-layer assembled onto silica microspheres to form a GO/SiO(2) composite stationary phase. All the characterizations of GO/SiO(2) by elemental analysis, Raman spectroscopy and Fourier transformed infrared spectrometry confirmed that with the increase of the assembled layer, GO gradually increases on the silica surface. The chromatographic properties of bare SiO(2) and GO/SiO(2) with different GO assembled layers show that the amount of GO plays an important role in the separation of analytes. Only the appropriate amount of GO on SiO(2) can perform a good chromatographic separation. The comparison between chromatographic performances of bare SiO(2) column, GO/SiO(2)-2 column and C18 commercial column clearly show that GO/SiO(2)-2 and C18 columns obtained a better separation; GO/SiO(2)-2 exhibits a large π-electron system and C18 exhibits hydrophobicity. The eluting order, peak width and resolution of analyte on GO/SiO(2)-2 column was highly dependent on the size of its π-electron system, while on the C18 column the decisive factor is its hydrophobic property.

The Classification of Diabetes Mellitus Using Kernel k-means

NASA Astrophysics Data System (ADS)

Alamsyah, M.; Nafisah, Z.; Prayitno, E.; Afida, A. M.; Imah, E. M.

2018-01-01

Diabetes Mellitus is a metabolic disorder which is characterized by chronicle hypertensive glucose. Automatics detection of diabetes mellitus is still challenging. This study detected diabetes mellitus by using kernel k-Means algorithm. Kernel k-means is an algorithm which was developed from k-means algorithm. Kernel k-means used kernel learning that is able to handle non linear separable data; where it differs with a common k-means. The performance of kernel k-means in detecting diabetes mellitus is also compared with SOM algorithms. The experiment result shows that kernel k-means has good performance and a way much better than SOM.

Separate Vertical Wirings for the Extra-articular Fractures of the Distal Pole of the Patella.

PubMed

Kim, Young Mo; Yang, Jun Young; Kim, Kyung Cheon; Kang, Chan; Joo, Yong Bum; Lee, Woo Yong; Hwang, Jung Mo

2011-12-01

To evaluate the usefulness of separate vertical wirings for extra-articular fracture of distal pole of patella. We have analyzed the clinical results of 18 cases that underwent separate vertical wirings for extra-articular fracture of distal pole of the patella from March 2005 to March 2010, by using the range of motion and Bostman score. Occurrence of complication was also evaluated. Additionally, by taking simple radiographs, the correlation between the postoperative degree of anterior transposition of bone fragment and the time of bone fusion, preoperative length of bone fragment, and occurrence of comminuted fracture were investigated. It took an average of 13.8 weeks for radiological bone union after separate vertical wiring fixation. Flexion contracture was an average of 0.8 degrees and further flexion was an average of 127.6°, and Bostman score was an average of 27.5 points (excellent in 12 cases, and good in 6 cases). On the first postoperative year, average flexion contracture was 0.6 degrees and further flexion was an average of 136.3°, which exhibited increased joint motion and recovery to normal range of motion, and Bostman score was an average of 28.7 points (excellent in 16 cases, and good in 2 cases). There was no statistically significant difference between the preoperative bone fragment length and presence of comminution, and degree of anterior transposition of bone fragment after fracture union on simple radiograph (p=0.175, p=0.146). We were able to obtain satisfactory clinical results, while preserving the bone fragment by separate vertical wiring fixation for extra-articular fracture of distal pole of patella. Moreover, the method is easy to perform, which is also considered as a useful surgical method for extra-articular fracture of distal pole of patella.

Determination of Yohimbine in Yohimbe Bark and Related Dietary Supplements Using UHPLC-UV/MS: Single-Laboratory Validation.

PubMed

Chen, Pei; Bryden, Noella

2015-01-01

A single-laboratory validation was performed on a practical ultra-HPLC (UHPLC)-diode array detector (DAD)/tandem MS method for determination of yohimbine in yohimbe barks and related dietary supplements. Good separation was achieved using a Waters Acquity ethylene bridged hybrid C18 column with gradient elution using 0.1% (v/v) aqueous ammonium hydroxide and 0.1% ammonium hydroxide in methanol as the mobile phases. The method can separate corynanthine from yohimbine in yohimbe bark extract, which is critical for accurate quantitation of yohimbine in yohimbe bark and related dietary supplements. Accuracy of the method was demonstrated using standard addition methods. Both intraday and interday precisions of the method were good. The method can be used without MS since yohimbine concentration in yohimbe barks and related dietary supplements are usually high enough for DAD detection, which can make it an easy and economical method for routine analysis of yohimbe barks and related dietary supplements. On the other hand, the method can be used with MS if desired for more challenging work such as biological and/or clinical studies.

Mixed Gas Hydrogen Sulfide Permeability and Separation Using Supported Polyphosphazene Membranes

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

Frederick F. Stewart; Christopher J. Orme

Three phosphazene polymers were characterized for permeability using a suite of pure gases, including H2S where high permeabilities were measured with respect to the other gases in the study. Furthermore, mixed gas selectivities were determined and compared to the ideal gas selectivities for the H2S/CH4, CO2/CH4, and Ar/CH4 gas pairs. The three phosphazenes represent a set of membrane materials differing by their polarities. Description of the polarity of each was performed using Hansen solubility parameters derived from group contributions for each chemical structure. A good correlation was observed between the polar Hansen parameter (äp) and the gas permeabilities of bothmore » CO2 and H2S. Furthermore, permeant gas critical temperatures were also found to correlate with permeability suggesting a solubility driven transport process. A comparison of the mixed gas permeabilities with the corresponding pure gas data revealed good agreement in the data, although the presence of more condensable gases hinders non-polar gas transport resulting in higher separation factors.« less

Preparation and characterization of monodisperse large-porous silica microspheres as the matrix for protein separation.

PubMed

Xia, Hongjun; Wan, Guangping; Zhao, Junlong; Liu, Jiawei; Bai, Quan

2016-11-04

High performance liquid chromatography (HPLC) is a kind of efficient separation technology and has been used widely in many fields. Micro-sized porous silica microspheres as the most popular matrix have been used for fast separation and analysis in HPLC. In this paper, the monodisperse large-porous silica microspheres with controllable size and structure were successfully synthesized with polymer microspheres as the templates and characterized. First, the poly(glycidyl methacrylate-co-ethyleneglycol dimethacrylate) microspheres (P GMA-EDMA ) were functionalized with tetraethylenepentamine (TEPA) to generate amino groups which act as a catalyst in hydrolysis of tetraethyl orthosilicate (TEOS) to form Si-containing low molecular weight species. Then the low molecular weight species diffused into the functionalized P GMA-EDMA microspheres by induction force of the amino groups to form polymer/silica hybrid microspheres. Finally, the organic polymer templates were removed by calcination, and the large-porous silica microspheres were obtained. The compositions, morphology, size distribution, specific surface area and pore size distribution of the porous silica microspheres were characterized by infrared analyzer, scanning-electron microscopy, dynamic laser scattering, the mercury intrusion method and thermal gravimetric analysis, respectively. The results show that the agglomeration of the hybrid microspheres can be overcome when the templates were functionalized with TEPA as amination reagent, and the yield of 95.7% of the monodisperse large-porous silica microspheres can be achieved with high concentration of polymer templates. The resulting large-porous silica microspheres were modified with octadecyltrichlorosilane (ODS) and the chromatographic evaluation was performed by separating the proteins and the digest of BSA. The baseline separation of seven kinds of protein standards was achieved, and the column delivered a better performance when separating BSA digests comparing with the commercial one currently available. The high column efficiency and good reproducibility present that the large-porous silica microspheres obtained can be used as a matrix for peptide and protein separation. Copyright © 2016 Elsevier B.V. All rights reserved.

Fine-motor skills testing and prediction of endovascular performance.

PubMed

Bech, Bo; Lönn, Lars; Schroeder, Torben V; Ringsted, Charlotte

2013-12-01

Performing endovascular procedures requires good control of fine-motor digital movements and hand-eye coordination. Objective assessment of such skills is difficult. Trainees acquire control of catheter/wire movements at various paces. However, little is known to what extent talent plays for novice candidates at entry to practice. To study the association between performance in a novel aptitude test of fine-motor skills and performance in simulated procedures. The test was based on manual course-tracking using a proprietary hand-operated roller-bar device coupled to a personal computer with monitor view rotation. A total of 40 test repetitions were conducted separately with each hand. Test scores were correlated with simulator performance. Group A (n = 14), clinicians with various levels of endovascular experience, performed a simulated procedure of contralateral iliac artery stenting. Group B (n = 19), medical students, performed 10 repetitions of crossing a challenging aortic bifurcation in a simulator. The test score differed markedly between the individuals in both groups, in particular with the non-dominant hand. Group A: the test score with the non-dominant hand correlated significantly with simulator performance assessed with the global rating scale SAVE (R = -0.69, P = 0.007). There was no association observed from performances with the dominant hand. Group B: there was no significant association between the test score and endovascular skills acquisition neither with the dominant nor with the non-dominant hand. Clinicians with increasing levels of endovascular technical experience had developed good fine-motor control of the non-dominant hand, in particular, that was associated with good procedural performance in the simulator. The aptitude test did not predict endovascular skills acquisition among medical students, thus, cannot be suggested for selection of novice candidates. Procedural experience and practice probably supplant the influence of innate abilities (talent) over time.

Verification of directed self-assembly (DSA) guide patterns through machine learning

NASA Astrophysics Data System (ADS)

Shim, Seongbo; Cai, Sibo; Yang, Jaewon; Yang, Seunghune; Choi, Byungil; Shin, Youngsoo

2015-03-01

Verification of full-chip DSA guide patterns (GPs) through simulations is not practical due to long runtime. We develop a decision function (or functions), which receives n geometry parameters of a GP as inputs and predicts whether the GP faithfully produces desired contacts (good) or not (bad). We take a few sample GPs to construct the function; DSA simulations are performed for each GP to decide whether it is good or bad, and the decision is marked in n-dimensional space. The hyper-plane that separates good marks and bad marks in that space is determined through machine learning process, and corresponds to our decision function. We try a single global function that can be applied to any GP types, and a series of functions in which each function is customized for different GP type; they are then compared and assessed in 10nm technology.

Model Performance Evaluation and Scenario Analysis ...

EPA Pesticide Factsheets

This tool consists of two parts: model performance evaluation and scenario analysis (MPESA). The model performance evaluation consists of two components: model performance evaluation metrics and model diagnostics. These metrics provides modelers with statistical goodness-of-fit measures that capture magnitude only, sequence only, and combined magnitude and sequence errors. The performance measures include error analysis, coefficient of determination, Nash-Sutcliffe efficiency, and a new weighted rank method. These performance metrics only provide useful information about the overall model performance. Note that MPESA is based on the separation of observed and simulated time series into magnitude and sequence components. The separation of time series into magnitude and sequence components and the reconstruction back to time series provides diagnostic insights to modelers. For example, traditional approaches lack the capability to identify if the source of uncertainty in the simulated data is due to the quality of the input data or the way the analyst adjusted the model parameters. This report presents a suite of model diagnostics that identify if mismatches between observed and simulated data result from magnitude or sequence related errors. MPESA offers graphical and statistical options that allow HSPF users to compare observed and simulated time series and identify the parameter values to adjust or the input data to modify. The scenario analysis part of the too

20 CFR 416.554 - Waiver of adjustment or recovery-against equity and good conscience.

Code of Federal Regulations, 2010 CFR

2010-04-01

... eligible couple that is legally separated and/or living apart for that part of an overpayment not received... subsequently found that the money was improperly paid. Recovery would be considered “against equity and good conscience.” Example 3: Mr. and Mrs. Smith—members of an eligible couple—separate in July. Later in July, Mr...

Combining simplicity with cost-effectiveness: Investigation of potential counterfeit of proton pump inhibitors through simulated formulations using thin-layer chromatography.

PubMed

Bhatt, Nejal M; Chavada, Vijay D; Sanyal, Mallika; Shrivastav, Pranav S

2016-11-18

A simple, accurate and precise high-performance thin-layer chromatographic method has been developed and validated for the analysis of proton pump inhibitors (PPIs) and their co-formulated drugs, available as binary combination. Planar chromatographic separation was achieved using a single mobile phase comprising of toluene: iso-propranol: acetone: ammonia 5.0:2.3:2.5:0.2 (v/v/v/v) for the analysis of 14 analytes on aluminium-backed layer of silica gel 60 FG 254 . Densitometric determination of the separated spots was done at 290nm. The method was validated according to ICH guidelines for linearity, precision and accuracy, sensitivity, specificity and robustness. The method showed good linear response for the selected drugs as indicated by the high values of correlation coefficients (≥0.9993). The limit of detection and limit of quantiation were in the range of 6.9-159.2ng/band and 20.8-478.1ng/band respectively for all the analytes. The optimized conditions afforded adequate resolution of each PPI from their co-formulated drugs and provided unambiguous identification of the co-formulated drugs from their homologous retardation factors (hR f ). The only limitation of the method was the inability to separate two PPIs, rabeprazole and lansoprazole from each other. Nevertheless, it is proposed that peak spectra recording and comparison with standard drug spot can be a viable option for assignment of TLC spots. The method performance was assessed by analyzing different laboratory simulated mixtures and some marketed formulations of the selected drugs. The developed method was successfully used to investigate potential counterfeit of PPIs through a series of simulated formulations with good accuracy and precision. Copyright © 2016 Elsevier B.V. All rights reserved.

CP decomposition approach to blind separation for DS-CDMA system using a new performance index

NASA Astrophysics Data System (ADS)

Rouijel, Awatif; Minaoui, Khalid; Comon, Pierre; Aboutajdine, Driss

2014-12-01

In this paper, we present a canonical polyadic (CP) tensor decomposition isolating the scaling matrix. This has two major implications: (i) the problem conditioning shows up explicitly and could be controlled through a constraint on the so-called coherences and (ii) a performance criterion concerning the factor matrices can be exactly calculated and is more realistic than performance metrics used in the literature. Two new algorithms optimizing the CP decomposition based on gradient descent are proposed. This decomposition is illustrated by an application to direct-sequence code division multiplexing access (DS-CDMA) systems; computer simulations are provided and demonstrate the good behavior of these algorithms, compared to others in the literature.

Hybrid magnet devices for molecule manipulation and small scale high gradient-field applications

DOEpatents

Humphries, David E [El Cerrito, CA; Hong, Seok-Cheol [Seoul, KR; Cozzarelli, legal representative, Linda A.; Pollard, Martin J [El Cerrito, CA; Cozzarelli, Nicholas R [Berkeley, CA

2009-01-06

The present disclosure provides a high performance hybrid magnetic structure made from a combination of permanent magnets and ferromagnetic pole materials which are assembled in a predetermined array. The hybrid magnetic structure provides means for separation and other biotechnology applications involving holding, manipulation, or separation of magnetizable molecular structures and targets. Also disclosed are hybrid magnetic tweezers able to exert approximately 1 nN of force to 4.5 .mu.m magnetic bead. The maximum force was experimentally measured to be .about.900 pN which is in good agreement with theoretical estimations and other measurements. In addition, a new analysis scheme that permits fast real-time position measurement in typical geometry of magnetic tweezers has been developed and described in detail.

Position-sensitive, fast ionization chambers

NASA Astrophysics Data System (ADS)

Lai, J.; Afanasieva, L.; Blackmon, J. C.; Deibel, C. M.; Gardiner, H. E.; Lauer, A.; Linhardt, L. E.; Macon, K. T.; Rasco, B. C.; Williams, C.; Santiago-Gonzalez, D.; Kuvin, S. A.; Almaraz-Calderon, S.; Baby, L. T.; Baker, J.; Belarge, J.; Wiedenhöver, I.; Need, E.; Avila, M. L.; Back, B. B.; DiGiovine, B.; Hoffman, C. R.

2018-05-01

A high-count-rate ionization chamber design with position-sensitivity has been developed and deployed at several accelerator facilities. Counting rates of ≥ 500 kHz with good Z-separation (up to 5% energy resolution) for particle identification have been demonstrated in a series of commissioning experiments. A position-sensitive capability, with a resolution of 3 mm, has been implemented for the first time to record position information and suppress pileup. The design and performance of the detectors are described.

Analysis of free amino acids in Amur sturgeon by ultra-performance liquid chromatography using pre-column derivatization with 6-aminoquinolyl-carbamyl.

PubMed

Sun, Yanchun; Xu, Xianzhu; Mou, Zhenbo; Wang, Jing; Tan, Zhijun; Wu, Song

2012-12-01

A rapid, sensitive, and reliable ultra-performance liquid chromatography (UPLC) coupled with photodiode array detection method was developed for the amino acid analysis of Amur sturgeon (Acipenser schrenckii Brandt). The method uses minimal sample volume and automated online precolumn derivitization of amino acids with fluorescent 6-aminoquinolyl-carbamyl reagent. The chromatographic separation was achieved by UPLC, which used a column with 1.7 μm particle packing that enabled higher speed of analysis, peak capacity, greater resolution, and increased sensitivity. Amino acid derivatives obtained under optimal conditions were separated on a Waters UPLC BEH C(18) column with Acetonitrile-acetate buffer as mobile phase. Matrix effects were investigated and good linearities with correlation coefficients better than 0.9949 were obtained over a wide range of 5-1000 μmol/L for all amino acids. The simple sample preparation and minimal sample volume make the method useful for the quantitation of 17 amino acids in Amur sturgeon samples. It is concluded that a rapid and robust platform based on UPLC was established, and a total of 17 amino acids of Amur sturgeon were tentatively detected. This method showed good accuracy and repeatability that can be used for the quantification of amino acids in real samples. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

The key to success: Gelled-electrolyte and optimized separators for stationary lead-acid batteries

NASA Astrophysics Data System (ADS)

Toniazzo, Valérie

The lead acid technology is nowadays considered one of the best suited for stationary applications. Both gel and AGM batteries are complementary technologies and can provide reliability and efficiency due to the constant optimization of the battery design and components. However, gelled-electrolyte batteries remain the preferred technology due to a better manufacturing background and show better performance mainly at low and moderate discharge rates. Especially, using the gel technology allows to get rid of the numerous problems encountered in most AGM batteries: drainage, stratification, short circuits due to dendrites, and mostly premature capacity loss due to the release of internal cell compression. These limitations are the result of the evident lack of an optimal separation system. In gel batteries, on the contrary, highly efficient polymeric separators are nowadays available. Especially, microporous separators based on PVC and silica have shown the best efficiency for nearly 30 years all over the world, and especially in Europe, where the gel technology was born. The improved performance of these separators is explained by the unique extrusion process, which leads to excellent wettability, and optimized physical properties. Because they are the key for the battery success, continuous research and development on separators have led to improved properties, which render the separator even better adapted to the more recent gel technology: the pore size distribution has been optimized to allow good oxygen transfer while avoiding dendrite growth, the pore volume has been increased, the electrical resistance and acid displacement reduced to such an extent that the electrical output of batteries has been raised both in terms of higher capacity and longer cycle life.

Refractive index-based detection of gradient elution liquid chromatography using chip-integrated microring resonator arrays.

PubMed

Wade, James H; Bailey, Ryan C

2014-01-07

Refractive index-based sensors offer attractive characteristics as nondestructive and universal detectors for liquid chromatographic separations, but a small dynamic range and sensitivity to minor thermal perturbations limit the utility of commercial RI detectors for many potential applications, especially those requiring the use of gradient elutions. As such, RI detectors find use almost exclusively in sample abundant, isocratic separations when interfaced with high-performance liquid chromatography. Silicon photonic microring resonators are refractive index-sensitive optical devices that feature good sensitivity and tremendous dynamic range. The large dynamic range of microring resonators allows the sensors to function across a wide spectrum of refractive indices, such as that encountered when moving from an aqueous to organic mobile phase during a gradient elution, a key analytical advantage not supported in commercial RI detectors. Microrings are easily configured into sensor arrays, and chip-integrated control microrings enable real-time corrections of thermal drift. Thermal controls allow for analyses at any temperature and, in the absence of rigorous temperature control, obviates extended detector equilibration wait times. Herein, proof of concept isocratic and gradient elution separations were performed using well-characterized model analytes (e.g., caffeine, ibuprofen) in both neat buffer and more complex sample matrices. These experiments demonstrate the ability of microring arrays to perform isocratic and gradient elutions under ambient conditions, avoiding two major limitations of commercial RI-based detectors and maintaining comparable bulk RI sensitivity. Further benefit may be realized in the future through selective surface functionalization to impart degrees of postcolumn (bio)molecular specificity at the detection phase of a separation. The chip-based and microscale nature of microring resonators also make it an attractive potential detection technology that could be integrated within lab-on-a-chip and microfluidic separation devices.

Capillary Electrophoresis - Optical Detection Systems

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

Sepaniak, M. J.

2001-08-06

Molecular recognition systems are developed via molecular modeling and synthesis to enhance separation performance in capillary electrophoresis and optical detection methods for capillary electrophoresis. The underpinning theme of our work is the rational design and development of molecular recognition systems in chemical separations and analysis. There have been, however, some subtle and exciting shifts in our research paradigm during this period. Specifically, we have moved from mostly separations research to a good balance between separations and spectroscopic detection for separations. This shift is based on our perception that the pressing research challenges and needs in capillary electrophoresis and electrokinetic chromatographymore » relate to the persistent detection and flow rate reproducibility limitations of these techniques (see page 1 of the accompanying Renewal Application for further discussion). In most of our work molecular recognition reagents are employed to provide selectivity and enhance performance. Also, an emerging trend is the use of these reagents with specially-prepared nano-scale materials. Although not part of our DOE BES-supported work, the modeling and synthesis of new receptors has indirectly supported the development of novel microcantilevers-based MEMS for the sensing of vapor and liquid phase analytes. This fortuitous overlap is briefly covered in this report. Several of the more significant publications that have resulted from our work are appended. To facilitate brevity we refer to these publications liberally in this progress report. Reference is also made to very recent work in the Background and Preliminary Studies Section of the Renewal Application.« less

Measurement of Separated Flow Structures Using a Multiple-Camera DPIV System. [conducted in the Langley Subsonic Basic Research Tunnel

NASA Technical Reports Server (NTRS)

Humphreys, William M., Jr.; Bartram, Scott M.

2001-01-01

A novel multiple-camera system for the recording of digital particle image velocimetry (DPIV) images acquired in a two-dimensional separating/reattaching flow is described. The measurements were performed in the NASA Langley Subsonic Basic Research Tunnel as part of an overall series of experiments involving the simultaneous acquisition of dynamic surface pressures and off-body velocities. The DPIV system utilized two frequency-doubled Nd:YAG lasers to generate two coplanar, orthogonally polarized light sheets directed upstream along the horizontal centerline of the test model. A recording system containing two pairs of matched high resolution, 8-bit cameras was used to separate and capture images of illuminated tracer particles embedded in the flow field. Background image subtraction was used to reduce undesirable flare light emanating from the surface of the model, and custom pixel alignment algorithms were employed to provide accurate registration among the various cameras. Spatial cross correlation analysis with median filter validation was used to determine the instantaneous velocity structure in the separating/reattaching flow region illuminated by the laser light sheets. In operation the DPIV system exhibited a good ability to resolve large-scale separated flow structures with acceptable accuracy over the extended field of view of the cameras. The recording system design provided enhanced performance versus traditional DPIV systems by allowing a variety of standard and non-standard cameras to be easily incorporated into the system.

Recognizing Age-Separated Face Images: Humans and Machines

PubMed Central

Yadav, Daksha; Singh, Richa; Vatsa, Mayank; Noore, Afzel

2014-01-01

Humans utilize facial appearance, gender, expression, aging pattern, and other ancillary information to recognize individuals. It is interesting to observe how humans perceive facial age. Analyzing these properties can help in understanding the phenomenon of facial aging and incorporating the findings can help in designing effective algorithms. Such a study has two components - facial age estimation and age-separated face recognition. Age estimation involves predicting the age of an individual given his/her facial image. On the other hand, age-separated face recognition consists of recognizing an individual given his/her age-separated images. In this research, we investigate which facial cues are utilized by humans for estimating the age of people belonging to various age groups along with analyzing the effect of one's gender, age, and ethnicity on age estimation skills. We also analyze how various facial regions such as binocular and mouth regions influence age estimation and recognition capabilities. Finally, we propose an age-invariant face recognition algorithm that incorporates the knowledge learned from these observations. Key observations of our research are: (1) the age group of newborns and toddlers is easiest to estimate, (2) gender and ethnicity do not affect the judgment of age group estimation, (3) face as a global feature, is essential to achieve good performance in age-separated face recognition, and (4) the proposed algorithm yields improved recognition performance compared to existing algorithms and also outperforms a commercial system in the young image as probe scenario. PMID:25474200

Recognizing age-separated face images: humans and machines.

PubMed

Yadav, Daksha; Singh, Richa; Vatsa, Mayank; Noore, Afzel

2014-01-01

Humans utilize facial appearance, gender, expression, aging pattern, and other ancillary information to recognize individuals. It is interesting to observe how humans perceive facial age. Analyzing these properties can help in understanding the phenomenon of facial aging and incorporating the findings can help in designing effective algorithms. Such a study has two components--facial age estimation and age-separated face recognition. Age estimation involves predicting the age of an individual given his/her facial image. On the other hand, age-separated face recognition consists of recognizing an individual given his/her age-separated images. In this research, we investigate which facial cues are utilized by humans for estimating the age of people belonging to various age groups along with analyzing the effect of one's gender, age, and ethnicity on age estimation skills. We also analyze how various facial regions such as binocular and mouth regions influence age estimation and recognition capabilities. Finally, we propose an age-invariant face recognition algorithm that incorporates the knowledge learned from these observations. Key observations of our research are: (1) the age group of newborns and toddlers is easiest to estimate, (2) gender and ethnicity do not affect the judgment of age group estimation, (3) face as a global feature, is essential to achieve good performance in age-separated face recognition, and (4) the proposed algorithm yields improved recognition performance compared to existing algorithms and also outperforms a commercial system in the young image as probe scenario.

Unsteady Flow Simulation of a Sweeping Jet Actuator Using a Lattice-Boltzmann Method

NASA Technical Reports Server (NTRS)

Duda, B.; Wessels, M.; Fares, E.; Vatsa, V.

2016-01-01

Active flow control technology is increasingly used in aerospace applications to control flow separation and to improve aerodynamic performance. In this paper, PowerFLOW is used to simulate the flow through a sweeping jet actuator at two different pressure ratios. The lower pressure ratio leads to a high subsonic flow, whereas the high pressure ratio produces a choked flow condition. Comparison of numerical results with experimental data is shown, which includes qualitatively good agreement of pressure histories and spectra. PIV measurements are also available but the simulation overestimates mean and fluctuation quantities outside the actuator. If supply pressure is matched at one point inside the mixing chamber a good qualitative agreement is achieved at all other monitor points.

Fγ: A new observable for photon-hadron discrimination in hybrid air shower events

NASA Astrophysics Data System (ADS)

Niechciol, M.; Risse, M.; Ruehl, P.; Settimo, M.; Younk, P. W.; Yushkov, A.

2018-01-01

To search for ultra-high-energy photons in primary cosmic rays, air shower observables are needed that allow a good separation between primary photons and primary hadrons. We present a new observable, Fγ, which can be extracted from ground-array data in hybrid events, where simultaneous measurements of the longitudinal and the lateral shower profile are performed. The observable is based on a template fit to the lateral distribution measured by the ground array with the template taking into account the complementary information from the measurement of the longitudinal profile, i.e. the primary energy and the geometry of the shower. Fγ shows a very good photon-hadron separation, which is even superior to the separation given by the well-known Xmax observable (the atmospheric depth of the shower maximum). At energies around 1 EeV (10 EeV), Fγ provides a background rejection better than 97.8 % (99.9 %) at a signal efficiency of 50 %. Advantages of the observable Fγ are its technical stability with respect to irregularities in the ground array (i.e. missing or temporarily non-operating stations) and that it can be applied over the full energy range accessible to the air shower detector, down to its threshold energy. Furthermore, Fγ complements nicely to Xmax such that both observables can well be combined to achieve an even better discrimination power, exploiting the rich information available in hybrid events.

Physically Gelled Room-Temperature Ionic Liquid-Based Composite Membranes for CO2/N-2 Separation: Effect of Composition and Thickness on Membrane Properties and Performance

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

Nguyen, PT; Voss, BA; Wiesenauer, EF

2013-07-03

An aspartame-based, low molecular-weight organic gelator (LMOG) was used to form melt-infused and composite membranes with two different imidazolium-based room-temperature ionic liquids (RTILs) for CO2 separation from N-2. Previous work demonstrated that LMOGs can gel RTILs at low, loading levels, and this aspartame-based LMOG was selected because it has been reported to gel a large number of RTILs. The imidazolium-based RTILs were used because of their inherent good properties for CO2/light gas separations. Analysis of the resulting bulk RTIL/LMOG physical gels showed that these materials have high sol-gel transition temperatures (ca. 135 degrees C) suitable for flue gas applications. Gasmore » permeabilities and burst pressure measurements of thick, melt infused membranes revealed a trade-off between high CO2 permeabilities and good mechanical stability as a function of the LMOG loading. Defect-free, composite membranes of the gelled RTILs were successfully fabricated by choosing an appropriate porous membrane support (hydrophobic PTFE) using a suitable coating technique (roller coating). The thicknesses of the applied composite gel layers ranged from 10.3 to 20.7 mu m, which represents an order of magnitude decrease in active layer thickness, compared to the original melt-infused gel RTIL membranes.« less

Mechanical recycling of waste electric and electronic equipment: a review.

PubMed

Cui, Jirang; Forssberg, Eric

2003-05-30

The production of electric and electronic equipment (EEE) is one of the fastest growing areas. This development has resulted in an increase of waste electric and electronic equipment (WEEE). In view of the environmental problems involved in the management of WEEE, many counties and organizations have drafted national legislation to improve the reuse, recycling and other forms of recovery of such wastes so as to reduce disposal. Recycling of WEEE is an important subject not only from the point of waste treatment but also from the recovery of valuable materials.WEEE is diverse and complex, in terms of materials and components makeup as well as the original equipment's manufacturing processes. Characterization of this waste stream is of paramount importance for developing a cost-effective and environmentally friendly recycling system. In this paper, the physical and particle properties of WEEE are presented. Selective disassembly, targeting on singling out hazardous and/or valuable components, is an indispensable process in the practice of recycling of WEEE. Disassembly process planning and innovation of disassembly facilities are most active research areas. Mechanical/physical processing, based on the characterization of WEEE, provides an alternative means of recovering valuable materials. Mechanical processes, such as screening, shape separation, magnetic separation, Eddy current separation, electrostatic separation, and jigging have been widely utilized in recycling industry. However, recycling of WEEE is only beginning. For maximum separation of materials, WEEE should be shredded to small, even fine particles, generally below 5 or 10mm. Therefore, a discussion of mechanical separation processes for fine particles is highlighted in this paper. Consumer electronic equipment (brown goods), such as television sets, video recorders, are most common. It is very costly to perform manual dismantling of those products, due to the fact that brown goods contain very low-grade precious metals and copper. It is expected that a mechanical recycling process will be developed for the upgrading of low metal content scraps.

Development of vinylic and acetylenic functionalized structures based on high permeable glassy polymers as membrane materials for gas mixtures separation

NASA Astrophysics Data System (ADS)

Roizard, D.; Kiryukhina, Y.; Masalev, A.; Khotimskiy, V.; Teplyakov, V.; Barth, D.

2013-03-01

There are several challenging separation problems in industries which can be solved with the help of membrane technologies. It is the case for instance of the purification of gas energy carriers (i.e. H2, CH4) from CO2 as well as the CO2 recovery from flue gas. Glassy polymers containing trimethylsilyl residues like poly(1-trimethylsilyl-1-propyne) [PTMSP] and polyvinyltrimethylsilane [PVTMS] are known to exhibit good membrane properties for gas separation. This paper reports two ways of improving their performances based on the controlled introduction of selective groups - alkyl imidazomium salts (C4I) and polyethyleneglycol (M-PEG)- able to enhance CO2 selectivity. CO2 Isotherm sorption data and permeability measurements have shown that the membrane performances could be significantly improved when C4I and M-PEG were introduced as residues covalently bounded to the main polymer chain. Moreover the introduced bromine reactive centres could also be used to induce chemical crosslinking giving rise to more resistant and stable membranes to organic vapours. With the C4I groups, the CO2 sorption could be enhanced by a factor 4.4.

Metal-organic frameworks for analytical chemistry: from sample collection to chromatographic separation.

PubMed

Gu, Zhi-Yuan; Yang, Cheng-Xiong; Chang, Na; Yan, Xiu-Ping

2012-05-15

In modern analytical chemistry researchers pursue novel materials to meet analytical challenges such as improvements in sensitivity, selectivity, and detection limit. Metal-organic frameworks (MOFs) are an emerging class of microporous materials, and their unusual properties such as high surface area, good thermal stability, uniform structured nanoscale cavities, and the availability of in-pore functionality and outer-surface modification are attractive for diverse analytical applications. This Account summarizes our research on the analytical applications of MOFs ranging from sampling to chromatographic separation. MOFs have been either directly used or engineered to meet the demands of various analytical applications. Bulk MOFs with microsized crystals are convenient sorbents for direct application to in-field sampling and solid-phase extraction. Quartz tubes packed with MOF-5 have shown excellent stability, adsorption efficiency, and reproducibility for in-field sampling and trapping of atmospheric formaldehyde. The 2D copper(II) isonicotinate packed microcolumn has demonstrated large enhancement factors and good shape- and size-selectivity when applied to on-line solid-phase extraction of polycyclic aromatic hydrocarbons in water samples. We have explored the molecular sieving effect of MOFs for the efficient enrichment of peptides with simultaneous exclusion of proteins from biological fluids. These results show promise for the future of MOFs in peptidomics research. Moreover, nanosized MOFs and engineered thin films of MOFs are promising materials as novel coatings for solid-phase microextraction. We have developed an in situ hydrothermal growth approach to fabricate thin films of MOF-199 on etched stainless steel wire for solid-phase microextraction of volatile benzene homologues with large enhancement factors and wide linearity. Their high thermal stability and easy-to-engineer nanocrystals make MOFs attractive as new stationary phases to fabricate MOF-coated capillaries for high-resolution gas chromatography (GC). We have explored a dynamic coating approach to fabricate a MOF-coated capillary for the GC separation of important raw chemicals and persistent organic pollutants with high resolution and excellent selectivity. We have combined a MOF-coated fiber for solid-phase microextraction with a MOF-coated capillary for GC separation, which provides an effective MOF-based tandem molecular sieve platform for selective microextraction and high-resolution GC separation of target analytes in complex samples. Microsized MOFs with good solvent stability are attractive stationary phases for high-performance liquid chromatography (HPLC). These materials have shown high resolution and good selectivity and reproducibility in both the normal-phase HPLC separation of fullerenes and substituted aromatics on MIL-101 packed columns and position isomers on a MIL-53(Al) packed column and the reversed-phase HPLC separation of a wide range of analytes from nonpolar to polar and acidic to basic solutes. Despite the above achievements, further exploration of MOFs in analytical chemistry is needed. Especially, analytical application-oriented engineering of MOFs is imperative for specific applications.

Facile room-temperature solution-phase synthesis of a spherical covalent organic framework for high-resolution chromatographic separation.

PubMed

Yang, Cheng-Xiong; Liu, Chang; Cao, Yi-Meng; Yan, Xiu-Ping

2015-08-07

A simple and facile room-temperature solution-phase synthesis was developed to fabricate a spherical covalent organic framework with large surface area, good solvent stability and high thermostability for high-resolution chromatographic separation of diverse important industrial analytes including alkanes, cyclohexane and benzene, α-pinene and β-pinene, and alcohols with high column efficiency and good precision.

In situ preparation of multilayer coated capillary column with HKUST-1 for separation of neutral small organic molecules by open tubular capillary electrochromatography.

PubMed

Xu, Yin-Yin; Lv, Wen-Juan; Ren, Cui-Ling; Niu, Xiao-Ying; Chen, Hong-Li; Chen, Xing-Guo

2018-01-12

The popularity of novel nanoparticles coated capillary column has aroused widespread attention of researchers. Metal organic frameworks (MOFs) with special structure and chemical properties have received great interest in separation sciences. This work presents the investigation of HKUST-1 (Hong Kong University of Science and Technology-1, called Cu 3 (BTC) 2 or MOF-199) nanoparticles as a new type of coating material for capillary electrochromatography. For the first time, three layers coating (3-LC), five layers coating (5-LC), ten layers coating (10-LC), fifteen layers coating (15-LC), twenty layers coating(20-LC) and twenty-five layers coating (25-LC) capillary columns coated with HKUST-1 nanoparticles were synthesized by covalent bond with in situ, layer-by-layer self-assembly approach. The results of scanning electron microscopy (SEM), X-ray diffraction (XRD) and plasma atomic emission spectrometry (ICP-AES) indicated that HKUST-1 was successfully grafted on the inner wall of the capillary. The separating performances of 3-LC, 5-LC, 10-LC, 15-LC, 20-LC and 25-LC open tubular (OT) capillary columns were studied with some neutral small organic molecules. The results indicated that the neutral small organic molecules were separated successfully with 10-LC, 15-LC and 20-LC OT capillary columns because of the size selectivity of lattice aperture and hydrophobicity of organic ligands. In addition, 10-LC and 15-LC OT capillary columns showed better performance for the separation of certain phenolic compounds. Furthermore, 10-LC, 15-LC and 20-LC OT capillary columns exhibited good intra-day repeatability with the relative standard deviations (RSDs; %) of migration time and peak areas lying in the range of 0.3-1.2% and 0.5-4.2%, respectively. For inter-day reproducibility, the RSDs of the three OT capillary columns were found to be lying in the range of 0.3-5.5% and 0.3-4.5% for migration time and peak area, respectively. The RSDs of retention times for column-to-column for three batches of 10-LC, 15-LC and 20-LC OT capillary columns were in the range from 2.3% to 7.2%. Moreover, the fabricated 10-LC, 15-LC and 20-LC OT capillary columns exhibited good repeatability and stability for separation, which could be used successively for more than 120 runs with no observable changes on the separation efficiency. Copyright © 2017 Elsevier B.V. All rights reserved.

A rational design for the separation of metallic and semiconducting single-walled carbon nanotubes using a magnetic field

NASA Astrophysics Data System (ADS)

Luo, Chengzhi; Wan, Da; Jia, Junji; Li, Delong; Pan, Chunxu; Liao, Lei

2016-06-01

The separation of metallic (m-) and semiconducting (s-) single-walled carbon nanotubes (SWNTs) without causing contamination and damage is a major challenge for SWNT-based devices. As a facile and nondestructive tool, the use of a magnetic field could be an ideal strategy to separate m-/s-SWNTs, based on the difference of magnetic susceptibilities. Here, we designed a novel magnetic field-assisted floating catalyst chemical vapor deposition system to separate m-/s-SWNTs. Briefly, m-SWNTs are attracted toward the magnetic pole, leaving s-SWNTs on the substrate. By using this strategy, s-SWNTs with a purity of 99% could be obtained, which is enough to construct high-performance transistors with a mobility of 230 cm2 V-1 s-1 and an on/off ratio of 106. We also established a model to quantitatively calculate the percentage of m-SWNTs on the substrate and this model shows a good match with the experimental data. Furthermore, our rational design also provides a new avenue for the growth of SWNTs with specific chirality and manipulated arrangement due to the difference of magnetic susceptibilities between different diameters, chiralities, and types.The separation of metallic (m-) and semiconducting (s-) single-walled carbon nanotubes (SWNTs) without causing contamination and damage is a major challenge for SWNT-based devices. As a facile and nondestructive tool, the use of a magnetic field could be an ideal strategy to separate m-/s-SWNTs, based on the difference of magnetic susceptibilities. Here, we designed a novel magnetic field-assisted floating catalyst chemical vapor deposition system to separate m-/s-SWNTs. Briefly, m-SWNTs are attracted toward the magnetic pole, leaving s-SWNTs on the substrate. By using this strategy, s-SWNTs with a purity of 99% could be obtained, which is enough to construct high-performance transistors with a mobility of 230 cm2 V-1 s-1 and an on/off ratio of 106. We also established a model to quantitatively calculate the percentage of m-SWNTs on the substrate and this model shows a good match with the experimental data. Furthermore, our rational design also provides a new avenue for the growth of SWNTs with specific chirality and manipulated arrangement due to the difference of magnetic susceptibilities between different diameters, chiralities, and types. Electronic supplementary information (ESI) available. See DOI: 10.1039/c6nr03928f

Quantitation in chiral capillary electrophoresis: theoretical and practical considerations.

PubMed

D'Hulst, A; Verbeke, N

1994-06-01

Capillary electrophoresis (CE) represents a decisive step forward in stereoselective analysis. The present paper deals with the theoretical aspects of the quantitation of peak separation in chiral CE. Because peak shape is very different in CE with respect to high performance liquid chromatography (HPLC), the resolution factor Rs, commonly used to describe the extent of separation between enantiomers as well as unrelated compounds, is demonstrated to be of limited value for the assessment of chiral separations in CE. Instead, the conjunct use of a relative chiral separation factor (RCS) and the percent chiral separation (% CS) is advocated. An array of examples is given to illustrate this. The practical aspects of method development using maltodextrins--which have been proposed previously as a major innovation in chiral selectors applicable in CE--are documented with the stereoselective analysis of coumarinic anticoagulant drugs. The possibilities of quantitation using CE were explored under two extreme conditions. Using ibuprofen, it has been demonstrated that enantiomeric excess determinations are possible down to a 1% level of optical contamination and stereoselective determinations are still possible with a good precision near the detection limit, increasing sample load by very long injection times. The theoretical aspects of this possibility are addressed in the discussion.

New Vectorial Propulsion System and Trajectory Control Designs for Improved AUV Mission Autonomy.

PubMed

Masmitja, Ivan; Gonzalez, Julian; Galarza, Cesar; Gomariz, Spartacus; Aguzzi, Jacopo; Del Rio, Joaquin

2018-04-17

Autonomous Underwater Vehicles (AUV) are proving to be a promising platform design for multidisciplinary autonomous operability with a wide range of applications in marine ecology and geoscience. Here, two novel contributions towards increasing the autonomous navigation capability of a new AUV prototype (the Guanay II) as a mix between a propelled vehicle and a glider are presented. Firstly, a vectorial propulsion system has been designed to provide full vehicle maneuverability in both horizontal and vertical planes. Furthermore, two controllers have been designed, based on fuzzy controls, to provide the vehicle with autonomous navigation capabilities. Due to the decoupled system propriety, the controllers in the horizontal plane have been designed separately from the vertical plane. This class of non-linear controllers has been used to interpret linguistic laws into different zones of functionality. This method provided good performance, used as interpolation between different rules or linear controls. Both improvements have been validated through simulations and field tests, displaying good performance results. Finally, the conclusion of this work is that the Guanay II AUV has a solid controller to perform autonomous navigation and carry out vertical immersions.

Analysis of aldehydes in beer by gas-diffusion microextraction: characterization by high-performance liquid chromatography-diode-array detection-atmospheric pressure chemical ionization-mass spectrometry.

PubMed

Gonçalves, Luís Moreira; Magalhães, Paulo Jorge; Valente, Inês Maria; Pacheco, João Grosso; Dostálek, Pavel; Sýkora, David; Rodrigues, José António; Barros, Aquiles Araújo

2010-06-11

In this work, a recently developed extraction technique for sample preparation aiming the analysis of volatile and semi-volatile compounds named gas-diffusion microextraction (GDME) is applied in the chromatographic analysis of aldehydes in beer. Aldehydes-namely acetaldehyde (AA), methylpropanal (MA) and furfural (FA)-were simultaneously extracted and derivatized with 2,4-dinitrophenylhydrazine (DNPH), then the derivatives were separated and analyzed by high-performance liquid chromatography with spectrophotometric detection (HPLC-UV). The identity of the eluted compounds was confirmed by high-performance liquid chromatography-atmospheric pressure chemical ionization-mass-spectrometry detection in the negative ion mode (HPLC-APCI-MS). The developed methodology showed good repeatability (ca. 5%) and linearity as well as good limits of detection (AA-12.3, FA-1.5 and MA 5.4microgL(-1)) and quantification (AA-41, FA-4.9 and MA 18microgL(-1)); it also appears to be competitive in terms of speed and cost of analysis. Copyright 2010 Elsevier B.V. All rights reserved.

[Simultaneous determination of 7 arsenic species in chicken muscle and chicken liver with high performance liquid chromatography-inductively coupled plasma mass spectrometry].

PubMed

Yang, Lijun; Hu, Qiaoru; Guo, Wei; Liu, Yumin; Song, Xiaohua; Zhang, Pengcheng

2011-05-01

A method for the simultaneous determination of 7 arsenic species was developed with high performance liquid chromatography and inductively coupled plasma mass spectrometry (HPLC-ICP-MS). The sample was extracted with artificial gastric juice. The HPLC separation was performed on an anion analytical column utilizing a gradient elution program of ammonium carbonate and water as the mobile phase. Identification and quantification were achieved by ICP-MS. Good linearities of 7 arsenic species were observed in the range from 1 microg/kg to 50 microg/kg with the correlation coefficients greater than 0.999. The average recoveries of 7 arsenic species spiked at the three levels of 1, 2 and 10 microg/kg ranged from 84.3% to 106.6% with the relative standard deviations of 1.4%-4.2%. The quantification limits of 7 arsenic species were 1 microg/kg. The method was proved to be good reproducibility, high sensitivity and simple preprocessing. This method is suitable for the simultaneous determination of 7 arsenic species in chicken muscle and chicken liver.

Deception and false belief in paranoia: modelling theory of mind stories.

PubMed

Shryane, Nick M; Corcoran, Rhiannon; Rowse, Georgina; Moore, Rosanne; Cummins, Sinead; Blackwood, Nigel; Howard, Robert; Bentall, Richard P

2008-01-01

This study used Item Response Theory (IRT) to model the psychometric properties of a Theory of Mind (ToM) stories task. The study also aimed to determine whether the ability to understand states of false belief in others and the ability to understand another's intention to deceive are separable skills, and to establish which is more sensitive to the presence of paranoia. A large and diverse clinical and nonclinical sample differing in levels of depression and paranoid ideation performed a ToM stories task measuring false belief and deception at first and second order. A three-factor IRT model was found to best fit the data, consisting of first- and second-order deception factors and a single false-belief factor. The first-order deception and false-belief factors had good measurement properties at low trait levels, appropriate for samples with reduced ToM ability. First-order deception and false beliefs were both sensitive to paranoid ideation with IQ predicting performance on false belief items. Separable abilities were found to underlie performance on verbal ToM tasks. However, paranoia was associated with impaired performance on both false belief and deception understanding with clear impairment at the simplest level of mental state attribution.

Development and validation of a capillary electrophoresis method for the determination of codeine, diphenhydramine, ephedrine and noscapine in pharmaceuticals.

PubMed

Gomez, María R; Sombra, Lorena; Olsina, Roberto A; Martínez, Luis D; Silva, María F

2005-01-01

The present work describes a simple, accurate and rapid method for the separation and simultaneous determination of codeine, diphenhydramine, ephedrine and noscapine present in cough-cold syrup formulations by capillary zone electrophoresis. Factors affecting the separation were the buffer pH and concentration, applied voltage, and presence of additives. Separations were carried out in less than 10 min with a 20 mM sodium tetraborate buffer, pH 8.50. The carrier electrolyte gave baseline separation with good resolution, great reproducibility and accuracy. Calibration plots were linear over at least three orders of magnitude of analyte concentrations, the lower limits of detection being within the range 0.42-1.33 microg ml(-1). Detection was performed by UV absorbance at wavelengths of 205 and 250 nm. Quantification of the components in actual syrup formulations was calculated against the responses of freshly prepared external standard solutions. The method was validated and met all analysis requirements of quality assurance and quality control. The procedure was fast and reliable and commercial pharmaceuticals could be analyzed without prior sample clean-up procedure.

Separation and purification of fructooligosaccharides on a zeolite fixed-bed column.

PubMed

Kuhn, Raquel Cristine; Mazutti, Marcio Antonio; Maugeri Filho, Francisco

2014-04-01

Fructooligosaccharides (FOS), a well-known prebiotic product, are obtained by enzymatic synthesis and consist of a mixture of mono- and disaccharides. In this work, a methodology for their separation and purification was developed using a zeolite fixed-bed column. The effects of column temperature (40-60°C), eluent flow rate (0.10-0.14 mL/min), injected to bed volume percent ratio (2.6-5.1%), and ethanol concentration in the eluent (40-60%, v/v) were investigated using a fractionary factorial design (2(4-1)), having the separation efficiency and purity as target responses. Additional experiments were performed as well, where the temperature and ethanol concentration were studied in a central composite design (2(2)). In this work, the zeolite fixed-bed column was shown to be a good alternative for FOS purification, allowing a FOS purity of 90% and separation efficiency of 6.86 between FOS and glucose, using an eluent at 45°C with 60% ethanol concentration. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

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

Wei, Xiaoliang; Nie, Zimin; Luo, Qingtao

Driven by the motivation of searching for low-cost membrane alternatives, a novel nanoporous polytetrafluoroethylene/silica composite separator has been prepared and evaluated for its use in all-vanadium mixed-acid redox flow battery. This separator consisting of silica particles enmeshed in a polytetrafluoroethylene fibril matrix has no ion exchange capacity and is featured with unique nanoporous structures, which function as the ion transport channels in redox flow battery operation, with an average pore size of 38nm and a porosity of 48%. This separator has produced excellent electrochemical performance in the all-vanadium mixed-acid system with energy efficiency delivery comparable to Nafion membrane and superiormore » rate capability and temperature tolerance. The separator also demonstrates an exceptional capacity retention capability over extended cycling, offering additional operational latitude towards conveniently mitigating the capacity decay that is inevitable for Nafion. Because of the inexpensive raw materials and simple preparation protocol, the separator is particularly low-cost, estimated to be at least an order of magnitude more inexpensive than Nafion. Plus the proven chemical stability due to the same backbone material as Nafion, this separator possesses a good combination of critical membrane requirements and shows great potential to promote market penetration of the all-vanadium redox flow battery by enabling significant reduction of capital and cycle costs.« less

Single-scan dual-tracer FLT+FDG PET tumor characterization.

PubMed

Kadrmas, Dan J; Rust, Thomas C; Hoffman, John M

2013-02-07

Rapid multi-tracer PET aims to image two or more tracers in a single scan, simultaneously characterizing multiple aspects of physiology and function without the need for repeat imaging visits. Using dynamic imaging with staggered injections, constraints on the kinetic behavior of each tracer are applied to recover individual-tracer measures from the multi-tracer PET signal. The ability to rapidly and reliably image both (18)F-fluorodeoxyglucose (FDG) and (18)F-fluorothymidine (FLT) would provide complementary measures of tumor metabolism and proliferative activity, with important applications in guiding oncologic treatment decisions and assessing response. However, this tracer combination presents one of the most challenging dual-tracer signal-separation problems--both tracers have the same radioactive half-life, and the injection delay is short relative to the half-life and tracer kinetics. This work investigates techniques for single-scan dual-tracer FLT+FDG PET tumor imaging, characterizing the performance of recovering static and dynamic imaging measures for each tracer from dual-tracer datasets. Simulation studies were performed to characterize dual-tracer signal-separation performance for imaging protocols with both injection orders and injection delays of 10-60 min. Better performance was observed when FLT was administered first, and longer delays before administration of FDG provided more robust signal-separation and recovery of the single-tracer imaging measures. An injection delay of 30 min led to good recovery (R > 0.96) of static image values (e.g. SUV), K(net), and K(1) as compared to values from separate, single-tracer time-activity curves. Recovery of higher order rate parameters (k(2), k(3)) was less robust, indicating that information regarding these parameters was harder to recover in the presence of statistical noise and dual-tracer effects. Performance of the dual-tracer FLT(0 min)+FDG(32 min) technique was further evaluated using PET/CT imaging studies in five patients with primary brain tumors where the data from separate scans of each tracer were combined to synthesize dual-tracer scans with known single-tracer components; results demonstrated similar dual-tracer signal recovery performance. We conclude that rapid dual-tracer FLT+FDG tumor imaging is feasible and can provide quantitative tumor imaging measures comparable to those from conventional separate-scan imaging.

Single-scan dual-tracer FLT+FDG PET tumor characterization

NASA Astrophysics Data System (ADS)

Kadrmas, Dan J.; Rust, Thomas C.; Hoffman, John M.

2013-02-01

Rapid multi-tracer PET aims to image two or more tracers in a single scan, simultaneously characterizing multiple aspects of physiology and function without the need for repeat imaging visits. Using dynamic imaging with staggered injections, constraints on the kinetic behavior of each tracer are applied to recover individual-tracer measures from the multi-tracer PET signal. The ability to rapidly and reliably image both 18F-fluorodeoxyglucose (FDG) and 18F-fluorothymidine (FLT) would provide complementary measures of tumor metabolism and proliferative activity, with important applications in guiding oncologic treatment decisions and assessing response. However, this tracer combination presents one of the most challenging dual-tracer signal-separation problems—both tracers have the same radioactive half-life, and the injection delay is short relative to the half-life and tracer kinetics. This work investigates techniques for single-scan dual-tracer FLT+FDG PET tumor imaging, characterizing the performance of recovering static and dynamic imaging measures for each tracer from dual-tracer datasets. Simulation studies were performed to characterize dual-tracer signal-separation performance for imaging protocols with both injection orders and injection delays of 10-60 min. Better performance was observed when FLT was administered first, and longer delays before administration of FDG provided more robust signal-separation and recovery of the single-tracer imaging measures. An injection delay of 30 min led to good recovery (R > 0.96) of static image values (e.g. SUV), Knet, and K1 as compared to values from separate, single-tracer time-activity curves. Recovery of higher order rate parameters (k2, k3) was less robust, indicating that information regarding these parameters was harder to recover in the presence of statistical noise and dual-tracer effects. Performance of the dual-tracer FLT(0 min)+FDG(32 min) technique was further evaluated using PET/CT imaging studies in five patients with primary brain tumors where the data from separate scans of each tracer were combined to synthesize dual-tracer scans with known single-tracer components; results demonstrated similar dual-tracer signal recovery performance. We conclude that rapid dual-tracer FLT+FDG tumor imaging is feasible and can provide quantitative tumor imaging measures comparable to those from conventional separate-scan imaging.

Single-scan dual-tracer FLT+FDG PET tumor characterization

PubMed Central

Kadrmas, Dan J; Rust, Thomas C; Hoffman, John M

2013-01-01

Rapid multi-tracer PET aims to image two or more tracers in a single scan, simultaneously characterizing multiple aspects of physiology and function without the need for repeat imaging visits. Using dynamic imaging with staggered injections, constraints on the kinetic behavior of each tracer are applied to recover individual-tracer measures from the multi-tracer PET signal. The ability to rapidly and reliably image both 18F-fluorodeoxyglucose (FDG) and 18F-fluorothymidine (FLT) would provide complementary measures of tumor metabolism and proliferative activity, with important applications in guiding oncologic treatment decisions and assessing response. However, this tracer combination presents one of the most challenging dual-tracer signal-separation problems—both tracers have the same radioactive half-life, and the injection delay is short relative to the half-life and tracer kinetics. This work investigates techniques for single-scan dual-tracer FLT+FDG PET tumor imaging, characterizing the performance of recovering static and dynamic imaging measures for each tracer from dual-tracer datasets. Simulation studies were performed to characterize dual-tracer signal-separation performance for imaging protocols with both injection orders and injection delays of 10–60 min. Better performance was observed when FLT was administered first, and longer delays before administration of FDG provided more robust signal-separation and recovery of the single-tracer imaging measures. An injection delay of 30 min led to good recovery (R > 0.96) of static image values (e.g. SUV), Knet, and K1 as compared to values from separate, single-tracer time-activity curves. Recovery of higher order rate parameters (k2, k3) was less robust, indicating that information regarding these parameters was harder to recover in the presence of statistical noise and dual-tracer effects. Performance of the dual-tracer FLT(0 min)+FDG(32 min) technique was further evaluated using PET/CT imaging studies in five patients with primary brain tumors where the data from separate scans of each tracer were combined to synthesize dual-tracer scans with known single-tracer components; results demonstrated similar dual-tracer signal recovery performance. We conclude that rapid dual-tracer FLT+FDG tumor imaging is feasible and can provide quantitative tumor imaging measures comparable to those from conventional separate-scan imaging. PMID:23296314

A transformation method for constrained-function minimization

NASA Technical Reports Server (NTRS)

Park, S. K.

1975-01-01

A direct method for constrained-function minimization is discussed. The method involves the construction of an appropriate function mapping all of one finite dimensional space onto the region defined by the constraints. Functions which produce such a transformation are constructed for a variety of constraint regions including, for example, those arising from linear and quadratic inequalities and equalities. In addition, the computational performance of this method is studied in the situation where the Davidon-Fletcher-Powell algorithm is used to solve the resulting unconstrained problem. Good performance is demonstrated for 19 test problems by achieving rapid convergence to a solution from several widely separated starting points.

Closed-Form Evaluation of Mutual Coupling in a Planar Array of Circular Apertures

NASA Technical Reports Server (NTRS)

Bailey, M. C.

1996-01-01

The integral expression for the mutual admittance between circular apertures in a planar array is evaluated in closed form. Very good accuracy is realized when compared with values that were obtained by numerical integration. Utilization of this closed-form expression, for all element pairs that are separated by more than one element spacing, yields extremely accurate results and significantly reduces the computation time that is required to analyze the performance of a large electronically scanning antenna array.

Using economic benefits for recycling in a separate collection centre managed as a "reverse supermarket": a sociological survey.

PubMed

De Feo, Giovanni; Polito, Anna Rita

2015-04-01

Separate collection centres (SCCs), where citizens can deliver recyclable fractions of municipal solid waste (MSW), in an "urban mining" perspective, can be considered a sort of "reverse supermarket", where people can deliver their recyclables in order to either obtain a waste fee reduction or shopping vouchers. The latter is the case of Baronissi, a town of around 17,000 inhabitants in the Province of Salerno, in the Campania region of Italy. The principal aim of the study was to investigate by means of a sociological survey the relationship between citizens and the separate collection program, with particular emphasis on the role played by the SCC. The separate collection system was evaluated either good or very good by 95.8% of the sample, while 99.2% expressed a good or very good evaluation of the quality of the service inside the separate collection centre: SCC users acted as a community as highlighted by the negative response of the Chi-square test for independence. Respecting the environment prevailed over saving time, obtaining eco-points, or saving money as the main reason why people went to the SCC. The majority of the respondents agreed if only putrescibles and residue should be collected directly from their homes, while all the other materials should be collected exclusively at the SCC, allowing to save money for the management of the kerbside collection system with a consequent further waste fee reduction for the residents. Copyright © 2015 Elsevier Ltd. All rights reserved.

A versatile bio-based material for efficiently removing toxic dyes, heavy metal ions and emulsified oil droplets from water simultaneously.

PubMed

Li, Daikun; Li, Qing; Mao, Daoyong; Bai, Ningning; Dong, Hongzhou

2017-12-01

Developing versatile materials for effective water purification is significant for environment and water source protection. Herein, a versatile bio-based material (CH-PAA-T) was reported by simple thermal cross-linking chitosan and polyacrylic acid which exhibits excellent performances for removing insoluble oil, soluble toxic dyes and heavy metal ions from water, simultaneously. The adsorption capacities are 990.1mgg -1 for methylene blue (MB) and 135.9mgg -1 for Cu 2+ , which are higher than most of present advanced absorbents. The adsorption towards organic dyes possesses high selectivity which makes CH-PAA-T be able to efficiently separate dye mixtures. The stable superoleophobicity under water endows CH-PAA-T good performance to separate toluene-in-water emulsion stabilized by Tween 80. Moreover, CH-PAA-T can be recycled for 10 times with negligible reduction of efficiency. Such versatile bio-based material is a potential candidate for water purification. Copyright © 2017. Published by Elsevier Ltd.

Neutral monosaccharide composition analysis of plant-derived oligo- and polysaccharides by high performance liquid chromatography.

PubMed

Yan, Jun; Shi, Songshan; Wang, Hongwei; Liu, Ruimin; Li, Ning; Chen, Yonglin; Wang, Shunchun

2016-01-20

A novel analytical method for neutral monosaccharide composition analysis of plant-derived oligo- and polysaccharides was developed using hydrophilic interaction liquid chromatography coupled to a charged aerosol detector. The effects of column type, additives, pH and column temperature on retention and separation were evaluated. Additionally, the method could distinguish potential impurities in samples, including chloride, sulfate and sodium, from sugars. The results of validation demonstrated that this method had good linearity (R(2) ≥ 0.9981), high precision (relative standard deviation ≤ 4.43%), and adequate accuracy (94.02-103.37% recovery) and sensitivity (detection limit: 15-40 ng). Finally, the monosaccharide compositions of the polysaccharide from Eclipta prostrasta L. and stachyose were successfully profiled through this method. This report represents the first time that all of these common monosaccharides could be well-separated and determined simultaneously by high performance liquid chromatography without additional derivatization. This newly developed method is convenient, efficient and reliable for monosaccharide analysis. Copyright © 2015 Elsevier Ltd. All rights reserved.

Pilot scale experiment with MBR operated in intermittent aeration condition: analysis of biological performance.

PubMed

Capodici, M; Di Bella, G; Di Trapani, D; Torregrossa, M

2015-02-01

The effect of intermittent aeration (IA) on a MBR system was investigated. The study was aimed at analyzing different working conditions and the influence of different IA cycles on the biological performance of the MBR pilot plant, in terms of organic carbon and ammonium removal as well as extracellular polymeric substances (EPSs) production. The membrane modules were placed in a separate compartment, continuously aerated. This configuration allowed to disconnect from the filtration stage the biological phenomena occurring into the IA bioreactor. The observed results highlighted good efficiencies, in terms of organic carbon and ammonium removal. It was noticed a significant soluble microbial products (SMPs) release, likely related to the higher metabolic stress that anoxic conditions exerted on the biomass. However, the proposed configuration, with the membranes in a separate compartment, allowed to reduce the EPSs in the membrane tank even during the non-aerated phase, thus lowering fouling development. Copyright © 2014 Elsevier Ltd. All rights reserved.

Validation of the DRAGON score in 12 stroke centers in anterior and posterior circulation.

PubMed

Strbian, Daniel; Seiffge, David J; Breuer, Lorenz; Numminen, Heikki; Michel, Patrik; Meretoja, Atte; Coote, Skye; Bordet, Régis; Obach, Victor; Weder, Bruno; Jung, Simon; Caso, Valeria; Curtze, Sami; Ollikainen, Jyrki; Lyrer, Philippe A; Eskandari, Ashraf; Mattle, Heinrich P; Chamorro, Angel; Leys, Didier; Bladin, Christopher; Davis, Stephen M; Köhrmann, Martin; Engelter, Stefan T; Tatlisumak, Turgut

2013-10-01

The DRAGON score predicts functional outcome in the hyperacute phase of intravenous thrombolysis treatment of ischemic stroke patients. We aimed to validate the score in a large multicenter cohort in anterior and posterior circulation. Prospectively collected data of consecutive ischemic stroke patients who received intravenous thrombolysis in 12 stroke centers were merged (n=5471). We excluded patients lacking data necessary to calculate the score and patients with missing 3-month modified Rankin scale scores. The final cohort comprised 4519 eligible patients. We assessed the performance of the DRAGON score with area under the receiver operating characteristic curve in the whole cohort for both good (modified Rankin scale score, 0-2) and miserable (modified Rankin scale score, 5-6) outcomes. Area under the receiver operating characteristic curve was 0.84 (0.82-0.85) for miserable outcome and 0.82 (0.80-0.83) for good outcome. Proportions of patients with good outcome were 96%, 93%, 78%, and 0% for 0 to 1, 2, 3, and 8 to 10 score points, respectively. Proportions of patients with miserable outcome were 0%, 2%, 4%, 89%, and 97% for 0 to 1, 2, 3, 8, and 9 to 10 points, respectively. When tested separately for anterior and posterior circulation, there was no difference in performance (P=0.55); areas under the receiver operating characteristic curve were 0.84 (0.83-0.86) and 0.82 (0.78-0.87), respectively. No sex-related difference in performance was observed (P=0.25). The DRAGON score showed very good performance in the large merged cohort in both anterior and posterior circulation strokes. The DRAGON score provides rapid estimation of patient prognosis and supports clinical decision-making in the hyperacute phase of stroke care (eg, when invasive add-on strategies are considered).

Gender Equality or Primacy of the Mother? Ambivalent Descriptions of Good Parents

ERIC Educational Resources Information Center

Perl-Littunen, Satu

2007-01-01

The ideology of gender equality is accepted as the norm in the Nordic countries. When asked to describe what they thought was required to be a good mother and a good father, Finnish informants (N = 387) showed uneasiness in describing good parents separately, however, often describing only a good mother. This article aims to explore the ambivalent…

Wide-pore silica-based ether-bonded phases for separation of proteins by high-performance hydrophobic-interaction and size-exclusion chromatography.

PubMed

Miller, N T; Feibush, B; Karger, B L

1984-12-21

This paper examines the use of wide-pore silica-based hydrophilic ether-bonded phases for the chromatographic separation of proteins under mild elution conditions. In particular, ether phases of the following structure identical to Si-(CH2)3-O-(CH2-CH2-O)n-R, where n = 1, 2, 3 and R = methyl, ethyl or n-butyl, have been prepared. These phases can be employed either in high-performance hydrophobic-interaction or size-exclusion chromatography, depending on mobile phase conditions. In the hydrophobic-interaction mode, a gradient of decreasing salt concentration, e.g., from 3 M ammonium sulfate (pH 6.0, 25 degrees C), yields sharp peaks with high mass recovery of active proteins. In this mode, retention can be controlled by salt type and concentration, as well as by column temperature. In the size-exclusion mode, use of medium ionic strength, e.g., 0.5 M ammonium acetate (pH 6.0) yields linear calibration of log (MW[eta]) vs. retention volume. Even at 0.05 M salt concentration, no stationary phase charge effects on protein elution are observed. These bonded-phase columns exhibit good column-to-column reproducibility and constant retention for at least five months of continual use. Examples of the high-performance separation of proteins in both modes are illustrated.

Quantitative determination of triterpenes from Amphiptherygium adstringens by liquid chromatography and thin-layer chromatography and morphological analysis of cuachalalate preparations.

PubMed

Navarrete, Andres; Avula, Bharathi; Joshi, Vaishali C; Ji, Xiuhong; Hersh, Paul; Khan, Ikhlas A

2006-01-01

Amphiptherygium adstringens (Anacardiaceae/Julianaceae), local name "cuachalalate," is used in folk medicine for the treatment of cholelithiasis, fevers, fresh wounds, hypercholesterolemia, gastritis, gastric ulcers, and cancer of the gastrointestinal tract. The development of column high-performance liquid chromatography-photodiode array detector (LC-PDA) and high-performance thin-layer chromatography (HPTLC)-densitometry methods for the determination of masticadienonic acid and 3-hydroxymasticadienonic acid in cuachalalate preparations is described in this paper. Good separation of the compounds could be achieved by both methods. Either might be preparable depending on the requirements. The LC separation was performed on a Phenomenex Synergi MAX-RP 80A reversed-phase column operated at 40 degrees C with detection at 215 nm. The plant materials were extracted with methanol by sonication. The triterpenes present in the plant material and commercial extracts were separated with an acetonitrile-water reagent alcohol isocratic system. The limit of detection was 0.1-0.2 microg/mL. The relative standard deviation values for the determination of triterpenes in plant extracts were less than 1.00%. This is the first report of an analytical method developed for the quantitative analysis of triterpenes from Amphiptherygium adstringens by LC-PDA and HPTLC. The stem bark showed higher amounts of triterpenes, and low amounts in root and stem root. The microscopic description of the crude drug of cuachalalate was also provided.

Porous CoO nanostructures grown on three-dimension graphene foams for supercapacitors electrodes

NASA Astrophysics Data System (ADS)

Deng, Wei; Lan, Wei; Sun, Yaru; Su, Qing; Xie, Erqing

2014-06-01

Three-dimensional graphene foams with good conductivity, light weight and chemical stability were produced by chemical vapor deposition. Then porous CoO nanowalls were deposited on graphene foam by a simple hydrothermal process and subsequent thermal treatment. This hybrid structures possessing large surface area in which the CoO nanowalls are separated by graphene foam with robust adhesion can directly serve as supercapacitor electrode including current collector without the need of any other binder materials and conductive agents. Electrochemical tests manifest a high specific capacitance of 231.87 F/g scaled to the mass of CoO (139.47 F/g for total mass of electrodes) at 1 A/g current, good rate capability and excellent cycling performance of >98% capacitance retention over 1000 cycles at 7 A/g current. The high conductivity, light weight and rational architectures, which provide fast electron pathway and the low diffusion resistance of ions, are responsible for the high performance of the electrodes.

Flexible ultraviolet photodetectors based on ZnO-SnO2 heterojunction nanowire arrays

NASA Astrophysics Data System (ADS)

Lou, Zheng; Yang, Xiaoli; Chen, Haoran; Liang, Zhongzhu

2018-02-01

A ZnO-SnO2 nanowires (NWs) array, as a metal oxide semiconductor, was successfully synthesized by a near-field electrospinning method for the applications as high performance ultraviolet photodetectors. Ultraviolet photodetectors based on a single nanowire exhibited excellent photoresponse properties to 300 nm ultraviolet light illumination including ultrahigh I on/I off ratios (up to 103), good stability and reproducibility because of the separation between photo-generated electron-hole pairs. Moreover, the NWs array shows an enhanced photosensing performance. Flexible photodetectors on the PI substrates with similar tendency properties were also fabricated. In addition, under various bending curvatures and cycles, the as-fabricated flexible photodetectors revealed mechanical flexibility and good stable electrical properties, showing that they have the potential for applications in future flexible photoelectron devices. Project supported by the National Science Foundation of China (No. 61504136) and the State Key Laboratory of Applied Optics, Changchun Institute of Optics, Fine and Physics, Chinese Academy of Sciences.

Determination of MDMA, MDA, MDEA and MBDB in oral fluid using high performance liquid chromatography with native fluorescence detection.

PubMed

Concheiro, Marta; de Castro, Ana; Quintela, Oscar; López-Rivadulla, Manuel; Cruz, Angelines

2005-06-10

This paper describes the analytical methodology for the determination of MDMA, MDA, MDEA and MBDB in oral fluid. After a liquid-liquid extraction, the analysis was carried out by high performance liquid chromatography (HPLC), with fluorescence detection. The detector wavelength was fixed at 285 nm for excitation and 320 nm for emission. The mobile phase, a mixture of phosphate buffer (pH=5) and acetonitrile (75:25), and the column, Kromasil 100 C8 5 microm 250 mm x 4.6mm, allowed good separation of the compounds in an isocratic mode in only 10 min. The method was validated and showed good limits of detection (2 ng/mL) and quantitation (10 ng/mL) for all the amphetamine derivatives. No interfering substances were detected. A stability study of these compounds in oral fluid stored at three different temperatures (-18, 4 and 20 degrees C) over 10 weeks was conducted, showing a time-dependent degradation of the four compounds.

Numerical modeling of separated flows at moderate Reynolds numbers appropriate for turbine blades and unmanned aero vehicles

NASA Astrophysics Data System (ADS)

Castiglioni, Giacomo

Flows over airfoils and blades in rotating machinery, for unmanned and micro-aerial vehicles, wind turbines, and propellers consist of a laminar boundary layer near the leading edge that is often followed by a laminar separation bubble and transition to turbulence further downstream. Typical Reynolds averaged Navier-Stokes turbulence models are inadequate for such flows. Direct numerical simulation is the most reliable, but is also the most computationally expensive alternative. This work assesses the capability of immersed boundary methods and large eddy simulations to reduce the computational requirements for such flows and still provide high quality results. Two-dimensional and three-dimensional simulations of a laminar separation bubble on a NACA-0012 airfoil at Rec = 5x104 and at 5° of incidence have been performed with an immersed boundary code and a commercial code using body fitted grids. Several sub-grid scale models have been implemented in both codes and their performance evaluated. For the two-dimensional simulations with the immersed boundary method the results show good agreement with the direct numerical simulation benchmark data for the pressure coefficient Cp and the friction coefficient Cf, but only when using dissipative numerical schemes. There is evidence that this behavior can be attributed to the ability of dissipative schemes to damp numerical noise coming from the immersed boundary. For the three-dimensional simulations the results show a good prediction of the separation point, but an inaccurate prediction of the reattachment point unless full direct numerical simulation resolution is used. The commercial code shows good agreement with the direct numerical simulation benchmark data in both two and three-dimensional simulations, but the presence of significant, unquantified numerical dissipation prevents a conclusive assessment of the actual prediction capabilities of very coarse large eddy simulations with low order schemes in general cases. Additionally, a two-dimensional sweep of angles of attack from 0° to 5° is performed showing a qualitative prediction of the jump in lift and drag coefficients due to the appearance of the laminar separation bubble. The numerical dissipation inhibits the predictive capabilities of large eddy simulations whenever it is of the same order of magnitude or larger than the sub-grid scale dissipation. The need to estimate the numerical dissipation is most pressing for low-order methods employed by commercial computational fluid dynamics codes. Following the recent work of Schranner et al., the equations and procedure for estimating the numerical dissipation rate and the numerical viscosity in a commercial code are presented. The method allows for the computation of the numerical dissipation rate and numerical viscosity in the physical space for arbitrary sub-domains in a self-consistent way, using only information provided by the code in question. The method is first tested for a three-dimensional Taylor-Green vortex flow in a simple cubic domain and compared with benchmark results obtained using an accurate, incompressible spectral solver. Afterwards the same procedure is applied for the first time to a realistic flow configuration, specifically to the above discussed laminar separation bubble flow over a NACA 0012 airfoil. The method appears to be quite robust and its application reveals that for the code and the flow in question the numerical dissipation can be significantly larger than the viscous dissipation or the dissipation of the classical Smagorinsky sub-grid scale model, confirming the previously qualitative finding.

Artificial receptor-functionalized nanoshell: facile preparation, fast separation and specific protein recognition

NASA Astrophysics Data System (ADS)

Ouyang, Ruizhuo; Lei, Jianping; Ju, Huangxian

2010-05-01

This work combined molecular imprinting technology with superparamagnetic nanospheres as the core to prepare artificial receptor-functionalized magnetic nanoparticles for separation of homologous proteins. Using dopamine as a functional monomer, novel surface protein-imprinted superparamagnetic polydopamine (PDA) core-shell nanoparticles were successfully prepared in physiological conditions, which could maintain the natural structure of a protein template and achieved the development of molecularly imprinted polymers (MIPs) from one dimension to zero dimension for efficient recognition towards large biomolecules. The resultant nanoparticles could be used for convenient magnetic separation of homologous proteins with high specificity. The nanoparticles possessed good monodispersibility, uniform surface morphology and high saturation magnetization value. The bound amounts of template proteins measured by both indirect and direct methods were in good agreement. The maximum number of imprinted cavities on the surface of the bovine hemoglobin (Hb)-imprinted nanoshell was 2.21 × 1018 g - 1, which well matched their maximum binding capacity toward bovine Hb. Both the simple method for preparation of MIPs and the magnetic nanospheres showed good application potential in fast separation, effective concentration and selective biosensing of large protein molecules.

A rapid quantitative determination of phenolic acids in Brassica oleracea by capillary zone electrophoresis.

PubMed

Lee, Iris S L; Boyce, Mary C; Breadmore, Michael C

2011-07-15

A simple and rapid capillary zone electrophoresis method to quantitatively determine the phenolic acid contents in brassica vegetables is described. Phenolic compounds were extracted from broccoli, broccolini, Brussels sprouts, cabbage and cauliflower and the main hydroxycinnamic acids (sinapic, ferulic, p-coumaric and caffeic acids) were isolated by solid phase extraction with C18 cartridges. Using an optimised method, the four analytes were separated in less than 7min in a 50μm×60cm capillary with a 15mM borate buffer (pH=9.13) and a separation voltage of 30kV at 30°C. A linear relationship was observed for the method (r=0.9997-0.9999) with detection limits ranging from 1.1 to 2.3mg/kg of vegetables for the analytes. This method demonstrated good reproducibility with coefficients of variation of less than 5% for peak area and less than 1% for migration time (n=7). The method was successfully applied to quantitatively determine the phenolic acid contents in a range of brassica vegetables and the results were in good agreement when compared to those from high performance liquid chromatography analysis. Crown Copyright © 2011. Published by Elsevier Ltd. All rights reserved.

Ultralight super-hydrophobic carbon aerogels based on cellulose nanofibers/poly(vinyl alcohol)/graphene oxide (CNFs/PVA/GO) for highly effective oil-water separation.

PubMed

Xu, Zhaoyang; Zhou, Huan; Tan, Sicong; Jiang, Xiangdong; Wu, Weibing; Shi, Jiangtao; Chen, Peng

2018-01-01

With the worsening of the oil-product pollution problem, oil-water separation has attracted increased attention in recent years. In this study, a porous three-dimensional (3D) carbon aerogel based on cellulose nanofibers (CNFs), poly(vinyl alcohol) (PVA) and graphene oxide (GO) was synthesized by a facile and green approach. The resulting CNF/PVA/GO aerogels were synthesized through an environmentally friendly freeze-drying process and then carbonized to yield CNF/PVA/GO carbon aerogels with low density (18.41 mg cm -3 ), high porosity (98.98%), a water contact angle of 156° (super-hydrophobic) and high oil absorption capacity (97 times its own weight). The carbonization treatment of the CNF/PVA/GO aerogel not only improved the hydrophobic properties but also enhanced the adsorption capacity and specific surface area. Given the many good performance characteristics and the facile preparation process of carbon aerogels, these materials are viable candidates for use in oil-water separation and environmental protection.

Chlorophyll and carotenoid pigments of prochloron (prochlorophyta)

NASA Technical Reports Server (NTRS)

Paerl, H. W.; Lewin, R. A.; Cheng, L.

1983-01-01

High-performance liquid chromatography (HPLC) with a gradient-elution technique was utilized to separate and quantify chlorophylls a and b as well as major carotenoid pigments present in freeze-dried preprations of prochloron-didemnid associations and in Prochloron cells separated from host colonies. Results confirm earlier spectrophotometric evidence for both chlorophylls a and b in this prokaryote. Chlorophyll a:b ratios range from 4.14 to 19.71; generally good agreement was found between ratios determined in isolated cell preprations and in symbiotic colonies (in hospite). These values are 1.5 to 5-fold higher than ratios determined in a variety of eukaryotic green plants. The carotenoids in Prochloron are quantitatively and qualitatively similar to those found in various freshwater and marine blue-green algae (cyanopbytes) from high-light environments. However, Prochloron differs from cyanophytes by the absence of myxoxanthophyll and related glycosidic carotenoids. It pigment characteristics are considered sufficiently different from those of cyanophytes to justify its assignment to a separate algal division.

OPTIMIZATION AND VALIDATION OF HPLC METHOD FOR TETRAMETHRIN DETERMINATION IN HUMAN SHAMPOO FORMULATION.

PubMed

Zeric Stosic, Marina Z; Jaksic, Sandra M; Stojanov, Igor M; Apic, Jelena B; Ratajac, Radomir D

2016-11-01

High-performance liquid chromatography (HPLC) method with diode array detection (DAD) were optimized and validated for separation and determination of tetramethrin in an antiparasitic human shampoo. In order to optimize separation conditions, two different columns, different column oven temperatures, as well as mobile phase composition and ratio, were tested. Best separation was achieved on the Supelcosil TM LC-18- DB column (4.6 x 250 mm), particle size 5 jim, with mobile phase methanol : water (78 : 22, v/v) at a flow rate of 0.8 mL/min and at temperature of 30⁰C. The detection wavelength of the detector was set at 220 nm. Under the optimum chromatographic conditions, standard calibration curve was measured with good linearity [r2 = 0.9997]. Accuracy of the method defined as a mean recovery of tetramethrin from shampoo matrix was 100.09%. The advantages of this method are that it can easily be used for the routine analysis of drug tetramethrin in pharmaceutical formulas and in all pharmaceutical researches involving tetramethrin.

Valence electronic structure of cobalt phthalocyanine from an optimally tuned range-separated hybrid functional.

PubMed

Brumboiu, Iulia Emilia; Prokopiou, Georgia; Kronik, Leeor; Brena, Barbara

2017-07-28

We analyse the valence electronic structure of cobalt phthalocyanine (CoPc) by means of optimally tuning a range-separated hybrid functional. The tuning is performed by modifying both the amount of short-range exact exchange (α) included in the hybrid functional and the range-separation parameter (γ), with two strategies employed for finding the optimal γ for each α. The influence of these two parameters on the structural, electronic, and magnetic properties of CoPc is thoroughly investigated. The electronic structure is found to be very sensitive to the amount and range in which the exact exchange is included. The electronic structure obtained using the optimal parameters is compared to gas-phase photo-electron data and GW calculations, with the unoccupied states additionally compared with inverse photo-electron spectroscopy measurements. The calculated spectrum with tuned γ, determined for the optimal value of α = 0.1, yields a very good agreement with both experimental results and with GW calculations that well-reproduce the experimental data.

Separator Decoration with Cobalt/Nitrogen Codoped Carbon for Highly Efficient Polysulfide Confinement in Lithium-Sulfur Batteries.

PubMed

Hu, Wen; Hirota, Yuichiro; Zhu, Yexin; Yoshida, Nao; Miyamoto, Manabu; Zheng, Tao; Nishiyama, Norikazu

2017-09-22

A macro-/mesoporous Co-N-C-decorated separator is proposed to confine and reutilize migrating polysulfides. Endowed with a desirable structure and synchronous lithio- and sulfiphilic chemistry, the macro-/mesoporous Co-N-C interface manipulates large polysulfide adsorption uptake, enabling good polysulfide adsorption kinetics, reversible electrocatalysis toward redox of anchored polysulfides, and facile charge transport. It significantly boosts the performance of a simple 70 wt % S/MWCNTs (MWCNTs=multi-walled carbon nanotubes) cathode, achieving high initial capacities (e.g., 1406 mAh g -1 at 0.2C, 1203 mAh g -1 at 1C), nearly 100 % Coulombic efficiencies, and high reversible capacities after cycle tests (e.g., 828.4 mAh g -1 at 1C after 100 cycles) at both low and high current rates. These results demonstrate that decorating separator with macro-/mesoporous Co-N-C paves a feasible way for developing advanced Li-S batteries. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Separation and simultaneous quantitation of PGF2α and its epimer 8-iso-PGF2α using modifier-assisted differential mobility spectrometry tandem mass spectrometry.

PubMed

Liang, Chunsu; Sun, Hui; Meng, Xiangjun; Yin, Lei; Fawcett, J Paul; Yu, Huaidong; Liu, Ting; Gu, Jingkai

2018-03-01

Because many therapeutic agents are contaminated by epimeric impurities or form epimers as a result of metabolism, analytical tools capable of determining epimers are increasingly in demand. This article is a proof-of-principle report of a novel DMS-MS/MS method to separate and simultaneously quantify epimers, taking PGF2 α and its 8-epimer, 8- iso -PGF2 α , as an example. Good accuracy and precision were achieved in the range of 10-500 ng/mL with a run time of only 1.5 min. Isopropanol as organic modifier facilitated a good combination of sensitivity and separation. The method is the first example of the quantitation of epimers without chromatographic separation.

[Influences of ion-suppressors on retention behaviors of nine food additives in reversed-phase high performance liquid chromatographic separation].

PubMed

Zhao, Yonggang; Chen, Xiaohong; Li, Xiaoping; Yao, Shanshan; Jin, Micong

2011-10-01

The influences of ion-suppressors on retention behaviors of nine food additives, i.e., acesulfame, saccharin, caffeine, aspartame, benzoic acid, sorbic acid, stevioside, dehydroacetic acid and neotame in reversed-phase high performance liquid chromatographic (RP-HPLC) separation were investigated. The organic modification effects of acids, i. e. , trifluoroacetic acid (TFA) and buffer salts, i. e. , TFA-ammonium acetate (AmAc) were studied emphatically. The relationships between retention factors of solutes and volume percentages of ion-suppressors in the mobile phase systems of acetonitrile-TFA aqueous solution and acetonitrile-TFA-AmAc aqueous solution were quantitatively established, separately. The separation of nine food additives was completed by a gradient elution with acetonitrile-TFA (0.01%, v/v)-AmAc (2. 5 mmol/L) aqueous solution as the mobile phases. An RP-HPLC method was established for the simultaneous determination of nine food additives in red wine. In the range of 10. 0 - 100. 0 mg/L, nine food additives showed good linearity with the correlation coefficients ( r2 ) larger than 0. 999 1. The limits of detection (LODs) were in the range of 0. 33 - 2. 36 mg/L and the limits of quantification (LOQs) were in the range of 1. 11 - 7. 80 mg/L. The spiked recoveries were between 87. 61% and 108. 4% with the relative standard deviations (RSDs) of 2. 2% -9. 4%. These results are of referential significance for the rapid establishment and accu- rate optimization of RP-HPLC separation for the simultaneous determination of food additives in other foods.

Non-noble electrocatalysts for alkaline fuel cells

NASA Technical Reports Server (NTRS)

Sarangapani, S.; Lessner, P.; Manoukian, M.; Giner, J.

1989-01-01

Carbons activated with macrocyclics have attracted increasing attention as alternative electrocatalysts for oxygen reduction. Initial activity of these catalysts is good, but performance declines rapidly. Pyrolyzing the macrocyclic on the carbon support leads to enhanced stability and the catalysts retain good activity. The approach described is designed to develop bulk doped catalysts with similar structures to pyrolyzed macrocyclic catalysts. The transition metal and coordinated ligands are dispersed throughout the bulk of the conductive carbon skeleton. Two approaches to realizing this concept are being pursued, both involving the doping of carbon precursors. In one approach, the precursor is a solid phase carbon-containing ion-exchange resin. The precursor is doped with a transition metal and/or nitrogen, and the resulting mixture is pyrolyzed. In the other approach, the precursor is a gas-phase hydrocarbon. This is introduced with a transition metal species and nitrogen species into a reactor and pyrolyzed. Several studies have been conducted to determine if there is a synergistic effect between the transition metal and nitrogen and the effect of different methods of introducing the metal-nitrogen (M-N) coordination on performance. One approach was to introduce the metal and nitrogen separately, for example, by sequentially doping FeCl3 and NH4OH into the resin. Catalysts were prepared from an undoped ion-exchange resin, a resin doped only with N, a resin doped only with Fe, and a resin doped with both Fe and N. Introduction of nitrogen alone has no beneficial effect on the performance of the catalysts. The introduction of the Fe alone significantly improves the performance in both the high and low current density regions. When both Fe and N are introduced, the performance at lower current densities (catalytic activity) is increased beyond that of the Fe-doped carbon, but the performance at higher current densities is similar to the carbon containing only Fe. Catalysts prepared from resins-Fe(bipy)3SO4 precursors have performance that is only slightly less then CoTMPP adsorbed and pyroloyzed on Vulcan XC-72. Their performance is much better than carbons which have had the N and Fe introduced separately.

Separation and determination of polyurethane amine catalysts in polyether polyols by using UHPLC-Q-TOF-MS on a reversed-phase/cation-exchange mixed-mode column.

PubMed

Li, Jiaxiao; Zhu, Marcel

2018-02-01

A simple, selective, and accurate ultra-high performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry method was established and validated for the efficient separation and quantification of polyurethane amine catalysts in polyether polyols. Amine catalysts were primarily separated in polyether polyol-based sample by solid-phase extraction, and further baseline separated on a reversed-phase/cation-exchange mixed-mode column (SiELC Primesep™ 200) using 0.1% trifluoroacetic acid/acetonitrile as a mobile phase in gradient elution mode at a flow rate of 0.2 mL/min. High-resolution quadrupole time-of-flight mass spectrometry analysis in electrospray ionization positive mode allowed the identification as N,N'-bis[3-(dimethylamino)propyl]urea, N-[2-(2-dimethylaminoethoxy)ethyl]-N-methyl-1,3-propanediamine, and N,N,N',N'-tetramethyldipropylenetriamine. The method was validated and presented good linearity for all the analytes in blank matrices within the concentration range of 0.20-5.0 or 0.1-2.0 μg/mL with the correlation coefficients (R 2 ) ranging from 0.986 to 0.997. Method recovery ranged within 81-105% at all three levels (80, 100, and 120% of the original amount) with relative standard deviations of 1.0-6.2%. The limits of detection were in the range of 0.007-0.051 μg/mL. Good precision was obtained with relative standard deviation below 3.2 and 0.72% for peak area and retention time of three amines, respectively. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Foveated optics

NASA Astrophysics Data System (ADS)

Bryant, Kyle R.

2016-05-01

Foveated imaging can deliver two different resolutions on a single focal plane, which might inexpensively allow more capability for military systems. The following design study results provide starting examples, lessons learned, and helpful setup equations and pointers to aid the lens designer in any foveated lens design effort. Our goal is to put robust sensor in a small package with no moving parts, but still be able to perform some of the functions of a sensor in a moving gimbal. All of the elegant solutions are out (for various reasons). This study is an attempt to see if lens designs can solve this problem and realize some gains in performance versus cost for airborne sensors. We determined a series of design concepts to simultaneously deliver wide field of view and high foveal resolution without scanning or gimbals. Separate sensors for each field of view are easy and relatively inexpensive, but lead to bulky detectors and electronics. Folding and beam-combining of separate optical channels reduces sensor footprint, but induces image inversions and reduced transmission. Entirely common optics provide good resolution, but cannot provide a significant magnification increase in the foveal region. Offsetting the foveal region from the wide field center may not be physically realizable, but may be required for some applications. The design study revealed good general guidance for foveated optics designs with a cold stop. Key lessons learned involve managing distortion, telecentric imagers, matching image inversions and numerical apertures between channels, reimaging lenses, and creating clean resolution zone splits near internal focal planes.

Magnetic Pd nanocatalyst Fe3O4@Pd for C-C bond formation and hydrogenation reactions

NASA Astrophysics Data System (ADS)

Biglione, Catalina; Cappelletti, Ariel L.; Strumia, Miriam C.; Martín, Sandra E.; Uberman, Paula M.

2018-05-01

Small core-shell Fe3O4@Pd superparamagnetic nanoparticles (MNPs) were obtained with good control in size and shape distribution by metal-complex thermal decomposition in organic media. The role of the stabilizer in the synthesis of MNPs was studied, employing oleylamine (OA), triphenylphosphine (TPP) and triphenylamine (TPA). The results revealed that, among the stabilizer investigated, the presence of oleylamine in the reaction media is crucial in order to obtain an uniform shell of Pd(0) in Fe3O4@Pd MNPs of 7 ± 1 nm. The synthesized core-shell MNPs were tested in Pd-catalyzed Heck-Mizoroki and Suzuki-Miyaura coupling reactions and p-chloronitrobenzene hydrogenation. High conversion, good reaction yields, and good TOF values were achieved in the three reaction systems with this nanocatalyst. The core-shell nanoparticle was easily recovered by a simple magnetic separation using a neodymium commercial magnet, which allowed performing up to four cycles of reuse. [Figure not available: see fulltext.

Combined quantitative and qualitative two-channel optical biopsy technique for discrimination of tumor borders

NASA Astrophysics Data System (ADS)

Bocher, Thomas; Beuthan, Juergen; Scheller, M.; Hopf, Juergen U. G.; Linnarz, Marietta; Naber, Rolf-Dieter; Minet, Olaf; Becker, Wolfgang; Mueller, Gerhard J.

1995-12-01

Conventional laser-induced fluorescence spectroscopy (LIFS) of endogenous chromophores like NADH (Nicotineamide Adenine Dinucleotide, reduced form) and PP IX (Protoporphyrin IX) provides information about the relative amounts of these metabolites in the observed cells. But for diagnostic applications the concentrations of these chromophores have to be determined quantitatively to establish tissue-independent differentiation criterions. It is well- known that the individually and locally varying optical tissue parameters are major obstacles for the determination of the true chromophore concentrations by simple fluorescence spectroscopy. To overcome these problems a fiber-based, 2-channel technique including a rescaled NADH-channel (delivering quantitative values) and a relative PP IX-channel was developed. Using the accumulated information of both channels can provide good tissue state separation. Ex-vivo studies with resected and frozen samples (with LN2) of squamous cells in the histologically confirmed states: normal, tumor border, inflammation and hyperplasia were performed. Each state was represented in this series with at least 7 samples. At the identical tissue spot both, the rescaled NADH-fluorescence and the relative PP IX- fluorescence, were determined. In the first case a nitrogen laser (337 nm, 500 ps, 200 microjoule, 10 Hz) in the latter case a diode laser (633 nm, 15 mW, cw) were used as excitation sources. In this ex-vivo study a good separation between the different tissue states was achieved. With a device constructed for clinical usage one quantitative, in-vivo NADH- measurement was done recently showing similar separation capabilities.

Simultaneous determination of piracetam and its four impurities by RP-HPLC with UV detection.

PubMed

Arayne, M Saeed; Sultana, Najma; Siddiqui, Farhan Ahmed; Mirza, Agha Zeeshan; Qureshi, Faiza; Zuberi, M Hashim

2010-08-01

A simple and rapid high-performance liquid chromatographic method for the separation and determination of piracetam and its four impurities, 2-oxopyrrolidin-1-yl)acetic acid, pyrrolidin-2-one, methyl (2-oxopyrrolidin-1-yl)acetate, and ethyl (2-oxopyrrolidin-1-yl)acetate, was developed. The separation was achieved on a reversed-phase C(18) Nucleosil column (25 cm x 0.46 cm, 10 microm). The mobile phase is composed of an aqueous solution containing 0.2 g/L of triethyl amine-acetonitrile (85:15, v/v). The pH of the mobile phase was adjusted to 6.5 with phosphoric acid at a flow rate of 1 mL/min at ambient temperature and UV detection at 205 nm. The developed method was found to give good separation between the pure drug and its four related substance. The polynomial regression data for the calibration plots showed good linear relationship in the concentration range of 50-10,000 ng/mL, 25-10,000 ng/mL, 45-10,000 ng/mL, 34-10,000 ng/mL, and 55-10,000 ng/mL, respectively, with r(2) = 0.9999. The method was validated for precision, accuracy, ruggedness, and recovery. The minimum quantifiable amounts were found to be 50 ng/mL of piracetam, 25 ng/mL of 2-oxopyrrolidin-1-yl)acetic acid, 45 ng/mL of pyrrolidin-2-one, 34 ng/mL of methyl (2-oxopyrrolidin-1-yl)acetate, and 55 ng/mL of ethyl (2-oxopyrrolidin-1-yl)acetate. Statistical analysis proves that the method is reproducible and selective for the estimation of piracetam as well as its related substance. As the method could effectively separate the drug from the related substances, it can be employed as a stability-indicating one. The proposed method shows high efficiency, allowing the separation of the main component piracetam from other impurities.

Oak ridge national laboratory automated clean chemistry for bulk analysis of environmental swipe samples

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

Bostick, Debra A.; Hexel, Cole R.; Ticknor, Brian W.

2016-11-01

To shorten the lengthy and costly manual chemical purification procedures, sample preparation methods for mass spectrometry are being automated using commercial-off-the-shelf (COTS) equipment. This addresses a serious need in the nuclear safeguards community to debottleneck the separation of U and Pu in environmental samples—currently performed by overburdened chemists—with a method that allows unattended, overnight operation. In collaboration with Elemental Scientific Inc., the prepFAST-MC2 was designed based on current COTS equipment that was modified for U/Pu separations utilizing Eichrom™ TEVA and UTEVA resins. Initial verification of individual columns yielded small elution volumes with consistent elution profiles and good recovery. Combined columnmore » calibration demonstrated ample separation without crosscontamination of the eluent. Automated packing and unpacking of the built-in columns initially showed >15% deviation in resin loading by weight, which can lead to inconsistent separations. Optimization of the packing and unpacking methods led to a reduction in the variability of the packed resin to less than 5% daily. The reproducibility of the automated system was tested with samples containing 30 ng U and 15 pg Pu, which were separated in a series with alternating reagent blanks. These experiments showed very good washout of both the resin and the sample from the columns as evidenced by low blank values. Analysis of the major and minor isotope ratios for U and Pu provided values well within data quality limits for the International Atomic Energy Agency. Additionally, system process blanks spiked with 233U and 244Pu tracers were separated using the automated system after it was moved outside of a clean room and yielded levels equivalent to clean room blanks, confirming that the system can produce high quality results without the need for expensive clean room infrastructure. Comparison of the amount of personnel time necessary for successful manual vs. automated chemical separations showed a significant decrease in hands-on time from 9.8 hours to 35 minutes for seven samples, respectively. This documented time savings and reduced labor translates to a significant cost savings per sample. Overall, the system will enable faster sample reporting times at reduced costs by limiting personnel hours dedicated to the chemical separation.« less

Development of an analytical method for separation of phenolic acids by ultra-performance convergence chromatography (UPC2) using a column packed with a sub-2-μm particle.

PubMed

Jiang, Hai; Yang, Liu; Xing, Xudong; Yan, Meiling; Guo, Xinyue; Yang, Bingyou; Wang, Qiu-Hong; Kuang, Hai-Xue

2018-05-10

Phenolic acids are important active components of certain Traditional Chinese Medicines (TCM) and have a wide range of biological effects. Separation and purification of phenolic acids remains challenging due to difficulties with quality control using existing chromatographic methods The purpose of this study was to compare the effects of different chromatographic columns and conditions for the separation of phenolic acids. The BEH column was determined to be optimal, providing efficient separation in the shortest time (17.00 min) using gradient elution with carbon dioxide as the mobile phase, methanol/acetonitrile (70:30, v/v) with 1% TFA as the modifier, and a flow rate of 0.8 mL/min. Good peak shapes were obtained, and the peak asymmetry values were close to 1.00 for all phenolic acids. The resolution was more than 2.83 for all separated peaks. The developed method was subsequently applied to the determination of phenolic acids in Xanthii Fructus. These results are beneficial for quality control and standardization of herbal drugs using UPC 2 , providing an efficient, rapid and environmentally friendly scientific basis for future analysis of phenolic acids. Copyright © 2018. Published by Elsevier B.V.

Single electron counting using a dual MCP assembly

NASA Astrophysics Data System (ADS)

Yang, Yuzhen; Liu, Shulin; Zhao, Tianchi; Yan, Baojun; Wang, Peiliang; Yu, Yang; Lei, Xiangcui; Yang, Luping; Wen, Kaile; Qi, Ming; Heng, Yuekun

2016-09-01

The gain, pulse height resolution and peak-to-valley ratio of single electrons detected by using a Chevron configured Microchannel Plate (MCP) assembly are studied. The two MCPs are separated by a 280 μm gap and are biased by four electrodes. The purpose of the study is to determine the optimum bias voltage arrangements for single electron counting. By comparing the results of various bias voltage combinations, we conclude that good performance for the electron counting can be achieved by operating the MCP assembly in saturation mode. In addition, by applying a small reverse bias voltage across the gap while adjusting the bias voltages of the MCPs, optimum performance of electron counting can be obtained.

Determination of virginiamycin M1 residue in tissues of swine and chicken by ultra-performance liquid chromatography tandem mass spectrometry.

PubMed

Wang, Xiaoyang; Wang, Mi; Zhang, Keyu; Hou, Ting; Zhang, Lifang; Fei, Chenzong; Xue, Feiqun; Hang, Taijun

2018-06-01

A reliable UPLC-MS/MS method with high sensitivity was developed and validated for the determination of virginiamycin M1 in muscle, fat, liver, and kidney samples of chicken and swine. Analytes were extracted using acetonitrile and extracts were defatted by N-hexane. Chromatographic separation was performed on a BEH C18 liquid chromatography column. The analytes were then detected using triplequadrupole mass spectrometry in positive electrospray ionization and multiple reaction monitoring mode. Calibration plots were constructed using standard working solutions and showed good linearity. Limits of quantification ranged from 2 to 60 ng mL -1 . Copyright © 2018 Elsevier Ltd. All rights reserved.

Integrating Education: Parekhian Multiculturalism and Good Practice

ERIC Educational Resources Information Center

McGlynn, Claire

2009-01-01

This paper explores the concept of good practice in integrating education in divided societies. Using Northern Ireland as a case study, the paper draws on data from eight schools (both integrated Catholic and Protestant, and separate) that are identified as exemplifying good practice in response to cultural diversity. Analysis is provided through…

19 CFR Appendix to Part 181 - Rules of Origin Regulations

Code of Federal Regulations, 2013 CFR

2013-04-01

... identified separately for sales promotion, marketing and after-sales service of goods on the financial... promotion, marketing and after-sales service of goods on the financial statements or cost accounts of the... sales promotion, marketing and after-sales service of goods on the financial statements or cost accounts...

19 CFR Appendix to Part 181 - Rules of Origin Regulations

Code of Federal Regulations, 2012 CFR

2012-04-01

... identified separately for sales promotion, marketing and after-sales service of goods on the financial... promotion, marketing and after-sales service of goods on the financial statements or cost accounts of the... sales promotion, marketing and after-sales service of goods on the financial statements or cost accounts...

19 CFR Appendix to Part 181 - Rules of Origin Regulations

Code of Federal Regulations, 2011 CFR

2011-04-01

... identified separately for sales promotion, marketing and after-sales service of goods on the financial... promotion, marketing and after-sales service of goods on the financial statements or cost accounts of the... sales promotion, marketing and after-sales service of goods on the financial statements or cost accounts...

19 CFR Appendix to Part 181 - Rules of Origin Regulations

Code of Federal Regulations, 2014 CFR

2014-04-01

... identified separately for sales promotion, marketing and after-sales service of goods on the financial... promotion, marketing and after-sales service of goods on the financial statements or cost accounts of the... sales promotion, marketing and after-sales service of goods on the financial statements or cost accounts...

Investigation of molybdate melts as an alternative method of reprocessing used nuclear fuel

DOE PAGES

Hames, Amber L.; Tkac, Peter; Paulenova, Alena; ...

2017-01-17

Here, an investigation of molybdate melts containing sodium molybdate (Na 2MoO 4) and molybdenum trioxide (MoO 3) to achieve the separation of uranium from fission products by crystallization has been performed. The separation is based on the difference in solubility of the fission product metal oxides compared to the uranium oxide or molybdate in the molybdate melt. The molybdate melt dissolves uranium dioxide at high temperatures, and upon cooling, uranium precipitates as uranium dioxide or molybdate, whereas the fission product metals remain soluble in the melt. Small-scale experiments using gram quantities of uranium dioxide have been performed to investigate themore » feasibility of UO 2 purification from the fission products. The composition of the uranium precipitate as well as data for partitioning of several fission product surrogates between the uranium precipitate and molybdate melt for various melt compositions are presented and discussed. The fission products Cs, Sr, Ru and Rh all displayed very large distribution ratios. The fission products Zr, Pd, and the lanthanides also displayed good distribution ratios (D > 10). A melt consisting of 20 wt% MoO 3-50 wt% Na 2MoO 4-30 wt% UO 2 heated to 1313 K and cooled to 1123 K for the physical separation of the UO 2 product from the melt, and washed once with Na 2MoO 4 displays optimum conditions for separation of the UO 2 from the fission products.« less

Fingerprint chromatogram analysis of extracts from the leaves of Tripterygium wilfordii Hook. F. by high performance liquid chromatography.

PubMed

Li, Ke; Wang, Shudong

2005-05-01

A simple and reliable high performance liquid chromatographic (HPLC) method has been developed and validated for the study of fingerprint chromatograms of extracts from the leaves of Tripterygium wilfordii Hook. F. (TWHF) and for controlling the quality of the herb. HPLC separation of the extracts was performed on a Lichrospher RP-18 column and detected by ultraviolet absorbance at 210 nm. The column temperature was maintained at 35 degrees C. A mobile phase composed of acetonitrile:H2O in the ratio of 39:61 (v/v) was found to be most suitable for this separation at a flow rate of 0.8 mL/min with isocratic elution. Under the chromatographic conditions described, the peak profile of the 10 components collected within 35 min made up the fingerprint of the extracts from leaves of TWHF with universal features. The fingerprint chromatograms had a good stability, precision, and reproducibility. The similarity of the extracts from leaves of TWHF collected in summer and winter was studied with triptolide as a reference peak. The method is suitable for differentiation of extracts from the leaves of TWHF, and can be used as a quality control method for this herb.

Determination of capsaicinoids in topical cream by liquid-liquid extraction and liquid chromatography.

PubMed

Kaale, Eliangiringa; Van Schepdael, Ann; Roets, Eugène; Hoogmartens, Jos

2002-11-07

A reversed-phase liquid chromatography (LC) method has been developed, optimised and validated for the separation and quantitation of capsaicin (CP) and dihydrocapsaicin (DHCP) in a topical cream formulation. Sample preparation involves liquid-liquid extraction prior to LC analysis. The method uses a Hypersil C(18) BDS, 5 micrometer, 250x4.6 mm I.D. column maintained at 35 degrees C. The mobile phase comprises methanol, water, acetonitrile (ACN) and acetic acid (47:42:10:1, v/v/v/v) at a flow rate of 1.0 ml/min. Robustness was evaluated by performing a central composite face-centred design (CCF) experiment. The method shows good selectivity, linearity, sensitivity and repeatability. The conditions allow the separation and quantitation of CP and DHCP without interference from the other substances contained in the cream.

Classification Studies in an Advanced Air Classifier

NASA Astrophysics Data System (ADS)

Routray, Sunita; Bhima Rao, R.

2016-10-01

In the present paper, experiments are carried out using VSK separator which is an advanced air classifier to recover heavy minerals from beach sand. In classification experiments the cage wheel speed and the feed rate are set and the material is fed to the air cyclone and split into fine and coarse particles which are collected in separate bags. The size distribution of each fraction was measured by sieve analysis. A model is developed to predict the performance of the air classifier. The objective of the present model is to predict the grade efficiency curve for a given set of operating parameters such as cage wheel speed and feed rate. The overall experimental data with all variables studied in this investigation is fitted to several models. It is found that the present model is fitting good to the logistic model.

Automatic blood detection in capsule endoscopy video

NASA Astrophysics Data System (ADS)

Novozámský, Adam; Flusser, Jan; Tachecí, Ilja; Sulík, Lukáš; Bureš, Jan; Krejcar, Ondřej

2016-12-01

We propose two automatic methods for detecting bleeding in wireless capsule endoscopy videos of the small intestine. The first one uses solely the color information, whereas the second one incorporates the assumptions about the blood spot shape and size. The original idea is namely the definition of a new color space that provides good separability of blood pixels and intestinal wall. Both methods can be applied either individually or their results can be fused together for the final decision. We evaluate their individual performance and various fusion rules on real data, manually annotated by an endoscopist.

Experimental and Computational Study of Underexpanded Jet Impingement Heat Transfer

NASA Technical Reports Server (NTRS)

Rufer, Shann J.; Nowak, Robert J.; Daryabeigi, Kamran; Picetti, Donald

2009-01-01

An experiment was performed to assess CFD modeling of a hypersonic-vehicle breach, boundary-layer flow ingestion and internal surface impingement. Tests were conducted in the NASA Langley Research Center 31-Inch Mach 10 Tunnel. Four simulated breaches were tested and impingement heat flux data was obtained for each case using both phosphor thermography and thin film gages on targets placed inside the model. A separate target was used to measure the surface pressure distribution. The measured jet impingement width and peak location are in good agreement with CFD analysis.

Separation and imaging diffractions by a sparsity-promoting model and subspace trust-region algorithm

NASA Astrophysics Data System (ADS)

Yu, Caixia; Zhao, Jingtao; Wang, Yanfei; Wang, Chengxiang; Geng, Weifeng

2017-03-01

The small-scale geologic inhomogeneities or discontinuities, such as tiny faults, cavities or fractures, generally have spatial scales comparable to or even smaller than the seismic wavelength. Therefore, the seismic responses of these objects are coded in diffractions and an attempt to high-resolution imaging can be made if we can appropriately image them. As the amplitudes of reflections can be several orders of magnitude larger than those of diffractions, one of the key problems of diffraction imaging is to suppress reflections and at the same time to preserve diffractions. A sparsity-promoting method for separating diffractions in the common-offset domain is proposed that uses the Kirchhoff integral formula to enforce the sparsity of diffractions and the linear Radon transform to formulate reflections. A subspace trust-region algorithm that can provide globally convergent solutions is employed for solving this large-scale computation problem. The method not only allows for separation of diffractions in the case of interfering events but also ensures a high fidelity of the separated diffractions. Numerical experiment and field application demonstrate the good performance of the proposed method in imaging the small-scale geological features related to the migration channel and storage spaces of carbonate reservoirs.

Multiple scales in metapopulations of public goods producers

NASA Astrophysics Data System (ADS)

Bauer, Marianne; Frey, Erwin

2018-04-01

Multiple scales in metapopulations can give rise to paradoxical behavior: in a conceptual model for a public goods game, the species associated with a fitness cost due to the public good production can be stabilized in the well-mixed limit due to the mere existence of these scales. The scales in this model involve a length scale corresponding to separate patches, coupled by mobility, and separate time scales for reproduction and interaction with a local environment. Contrary to the well-mixed high mobility limit, we find that for low mobilities, the interaction rate progressively stabilizes this species due to stochastic effects, and that the formation of spatial patterns is not crucial for this stabilization.

New Vectorial Propulsion System and Trajectory Control Designs for Improved AUV Mission Autonomy

PubMed Central

Gonzalez, Julian; Galarza, Cesar; Aguzzi, Jacopo; del Rio, Joaquin

2018-01-01

Autonomous Underwater Vehicles (AUV) are proving to be a promising platform design for multidisciplinary autonomous operability with a wide range of applications in marine ecology and geoscience. Here, two novel contributions towards increasing the autonomous navigation capability of a new AUV prototype (the Guanay II) as a mix between a propelled vehicle and a glider are presented. Firstly, a vectorial propulsion system has been designed to provide full vehicle maneuverability in both horizontal and vertical planes. Furthermore, two controllers have been designed, based on fuzzy controls, to provide the vehicle with autonomous navigation capabilities. Due to the decoupled system propriety, the controllers in the horizontal plane have been designed separately from the vertical plane. This class of non-linear controllers has been used to interpret linguistic laws into different zones of functionality. This method provided good performance, used as interpolation between different rules or linear controls. Both improvements have been validated through simulations and field tests, displaying good performance results. Finally, the conclusion of this work is that the Guanay II AUV has a solid controller to perform autonomous navigation and carry out vertical immersions. PMID:29673224

The performance of fine-grained and coarse-grained elastic network models and its dependence on various factors.

PubMed

Na, Hyuntae; Song, Guang

2015-07-01

In a recent work we developed a method for deriving accurate simplified models that capture the essentials of conventional all-atom NMA and identified two best simplified models: ssNMA and eANM, both of which have a significantly higher correlation with NMA in mean square fluctuation calculations than existing elastic network models such as ANM and ANMr2, a variant of ANM that uses the inverse of the squared separation distances as spring constants. Here, we examine closely how the performance of these elastic network models depends on various factors, namely, the presence of hydrogen atoms in the model, the quality of input structures, and the effect of crystal packing. The study reveals the strengths and limitations of these models. Our results indicate that ssNMA and eANM are the best fine-grained elastic network models but their performance is sensitive to the quality of input structures. When the quality of input structures is poor, ANMr2 is a good alternative for computing mean-square fluctuations while ANM model is a good alternative for obtaining normal modes. © 2015 Wiley Periodicals, Inc.

High-Throughput Microfludic Applications

PubMed Central

Doneanu, A.; Murphy, J.; Johnson, J.; Cohen, S.; Astarita, G.; Chakraborty, A.; Martin, LeRoy

2013-01-01

A novel platform was developed for the expansion of microfludic LC-MS beyond typical nanoscale applications into areas traditionally performed at analytical scales. The material used to fabricate the device allows for pressures of 12,000 psi. The integrated metal electrospray emitter supports flow rates from 100s of nl/min up to 8 μl/min and allows for the use of 150 μm in ID separation channels. Peak widths are on par with commercial ultra-high pressure LC instrumentation and cycle times as low as 10 min. System versatility will be demonstrated by several examples including intact proteins analysis, lipidomics and biopharmaceutical applications. All experiments were performed using a nanoflow system coupled with an oaTOF mass spectrometer fitted with an electrospray ionization source designed to accommodate the microfluidic device. The emitter is connected to a packed channel by zero dead-volume connections and incorporates the use of nebulising gas. The separation channel was 150 μm × 5 cm and packed with sub-2-μm reverse-phased particles of various chemistries. For intact protein analysis, using Ribonuclease A, Cyctochrome C, Holotransferrin and Apomyoglobin, good resolution was achieved using shorter alkyl chain resins. Additionally, light and heavy chains of reduced monoclonal antibodies could be separated. Separations were performed at 80°C, using a 3 μL/min linear gradient from 20% to 55% ACN over 5 min. Applicability for biopharmaceutical use is shown with minute amounts of Trastuzumab, demonstrating peak widths less than 6 s with 90% sequence coverage. Methionine oxidation and sites of glycosylation were also detected. The method was also employed for lipid analysis showing improved separation for the major classes, particularly inter and intra forms. The microfluidic system offered high retention time reproducibility with RSD values smaller than 0.2%. This is especially useful for lipidomic analysis, which requires the comparison of a large number of LC-MS chromatograms from multiple sample sets.

Freestanding hierarchically porous carbon framework decorated by polyaniline as binder-free electrodes for high performance supercapacitors

NASA Astrophysics Data System (ADS)

Miao, Fujun; Shao, Changlu; Li, Xinghua; Wang, Kexin; Lu, Na; Liu, Yichun

2016-10-01

Freestanding hierarchically porous carbon electrode materials with favorable features of large surface areas, hierarchical porosity and continuous conducting pathways are very attractive for practical applications in electrochemical devices. Herein, three-dimensional freestanding hierarchically porous carbon (HPC) materials have been fabricated successfully mainly by the facile phase separation method. In order to further improve the energy storage ability, polyaniline (PANI) with high pseudocapacitance has been decorated on HPC through in situ chemical polymerization of aniline monomers. Benefiting from the synergistic effects between HPC and PANI, the resulting HPC/PANI composites as electrode materials present dramatic electrochemical performance with high specific capacitance up to 290 F g-1 at 0.5 A g-1 and good rate capability with ∼86% (248 F g-1) capacitance retention at 64 A g-1 of initial capacitance in three-electrode configuration. Moreover, the as-assembled symmetric supercapacitor based on HPC/PANI composites also demonstrates good capacitive properties with high energy density of 9.6 Wh kg-1 at 223 W kg-1 and long-term cycling stability with 78% capacitance retention after 10 000 cycles. Therefore, this work provides a new approach for designing high-performance electrodes with exceptional electrochemical performance, which are very promising for practical application in the energy storage field.

Comparison of ultrafiltration and solid phase extraction for the separation of free and protein-bound serum copper for the Wilson's disease diagnosis.

PubMed

Bohrer, Denise; Do Nascimento, Paulo Cícero; Ramirez, Adrian G; Mendonça, Jean Karlo A; De Carvalho, Leandro M; Pomblum, Solange Cristina G

2004-07-01

The determination of the ratio free/protein-bound serum copper along with urinary copper can be used as a preliminary test for the Wilson's Disease diagnosis. In this work, the determination of these copper fractions in serum samples was carried out in two different ways; after separation of the copper bound to proteins from the free fraction by a column for protein adsorption and by ultrafiltration. As proteins can be adsorbed onto plastic polymeric surfaces, polyethylene (PE) with different molecular weights in powder form was investigated for protein adsorption. A small column was adapted in a flow system to carry out a solid-phase extraction (SPE) on-line. Preliminary experiments defined conditions for protein retention and elution and column saturation. Good performance was achieved using Mg(NO3)2 solution as carrier and methanol as eluent. The presence of proteins in both fraction (column effluent and eluate) was checked by the Coomassie Brilliant Blue test. Copper was measured by graphite furnace atomic absorption spectrometry. The measurement in the column effluent furnished the free-fraction of copper while the copper measured in the eluate the bound-fraction. The method was compared with ultrafiltration (20 kDa), measuring the free-copper in the ultrafiltrate. For the determination of protein-bound copper, the copper found in the ultrafitrate was discounted from the total copper measured in the sample. Serum samples of 10 individuals were analyzed by both methods with good agreement of the results. The regression plots, obtained by analysing the samples by both methods, presented r2 and slope of 0.97 and 0.96 for free copper and 1.00 and 1.00 for bound copper, respectively. Protein-bound copper (PB) concentrations ranged from 74 to 2074 microg/l and free-copper (F) from 22 to 54 microg/l. The ratio F/PB, calculated from SPE data, was 29.7% for one individual, with Wilson Disease well-characterized, and ranged from 1.2% to 5.2% for the others. The SPE method performed well in terms of accuracy and precision, and showed good agreement with the UF. Advantages of SPE are small sample volume (50 microl), separation carried out in 10 min, and the use of the same column for several analyses. Copyright 2004 Elsevier B.V.

A Numerical Analysis of Heat Transfer and Effectiveness on Film Cooled Turbine Blade Tip Models

NASA Technical Reports Server (NTRS)

Ameri, A. A.; Rigby, D. L.

1999-01-01

A computational study has been performed to predict the distribution of convective heat transfer coefficient on a simulated blade tip with cooling holes. The purpose of the examination was to assess the ability of a three-dimensional Reynolds-averaged Navier-Stokes solver to predict the rate of tip heat transfer and the distribution of cooling effectiveness. To this end, the simulation of tip clearance flow with blowing of Kim and Metzger was used. The agreement of the computed effectiveness with the data was quite good. The agreement with the heat transfer coefficient was not as good but improved away from the cooling holes. Numerical flow visualization showed that the uniformity of wetting of the surface by the film cooling jet is helped by the reverse flow due to edge separation of the main flow.

Does Parsonnet scoring model predict mortality following adult cardiac surgery in India?

PubMed

Srilata, Moningi; Padhy, Narmada; Padmaja, Durga; Gopinath, Ramachandran

2015-01-01

To validate the Parsonnet scoring model to predict mortality following adult cardiac surgery in Indian scenario. A total of 889 consecutive patients undergoing adult cardiac surgery between January 2010 and April 2011 were included in the study. The Parsonnet score was determined for each patient and its predictive ability for in-hospital mortality was evaluated. The validation of Parsonnet score was performed for the total data and separately for the sub-groups coronary artery bypass grafting (CABG), valve surgery and combined procedures (CABG with valve surgery). The model calibration was performed using Hosmer-Lemeshow goodness of fit test and receiver operating characteristics (ROC) analysis for discrimination. Independent predictors of mortality were assessed from the variables used in the Parsonnet score by multivariate regression analysis. The overall mortality was 6.3% (56 patients), 7.1% (34 patients) for CABG, 4.3% (16 patients) for valve surgery and 16.2% (6 patients) for combined procedures. The Hosmer-Lemeshow statistic was <0.05 for the total data and also within the sub-groups suggesting that the predicted outcome using Parsonnet score did not match the observed outcome. The area under the ROC curve for the total data was 0.699 (95% confidence interval 0.62-0.77) and when tested separately, it was 0.73 (0.64-0.81) for CABG, 0.79 (0.63-0.92) for valve surgery (good discriminatory ability) and only 0.55 (0.26-0.83) for combined procedures. The independent predictors of mortality determined for the total data were low ejection fraction (odds ratio [OR] - 1.7), preoperative intra-aortic balloon pump (OR - 10.7), combined procedures (OR - 5.1), dialysis dependency (OR - 23.4), and re-operation (OR - 9.4). The Parsonnet score yielded a good predictive value for valve surgeries, moderate predictive value for the total data and for CABG and poor predictive value for combined procedures.

Interfacial separation of a mature biofilm from a glass surface - A combined experimental and cohesive zone modelling approach.

PubMed

Safari, Ashkan; Tukovic, Zeljko; Cardiff, Philip; Walter, Maik; Casey, Eoin; Ivankovic, Alojz

2016-02-01

A good understanding of the mechanical stability of biofilms is essential for biofouling management, particularly when mechanical forces are used. Previous biofilm studies lack a damage-based theoretical model to describe the biofilm separation from a surface. The purpose of the current study was to investigate the interfacial separation of a mature biofilm from a rigid glass substrate using a combined experimental and numerical modelling approach. In the current work, the biofilm-glass interfacial separation process was investigated under tensile and shear stresses at the macroscale level, known as modes I and II failure mechanisms respectively. The numerical simulations were performed using a Finite Volume (FV)-based simulation package (OpenFOAM®) to predict the separation initiation using the cohesive zone model (CZM). Atomic force microscopy (AFM)-based retraction curve was used to obtain the separation properties between the biofilm and glass colloid at microscale level, where the CZM parameters were estimated using the Johnson-Kendall-Roberts (JKR) model. In this study CZM is introduced as a reliable method for the investigation of interfacial separation between a biofilm and rigid substrate, in which a high local stress at the interface edge acts as an ultimate stress at the crack tip.This study demonstrated that the total interfacial failure energy measured at the macroscale, was significantly higher than the pure interfacial separation energy obtained by AFM at the microscale, indicating a highly ductile deformation behaviour within the bulk biofilm matrix. The results of this study can significantly contribute to the understanding of biofilm detachments. Copyright © 2015 Elsevier Ltd. All rights reserved.

Development of the Orion Crew-Service Module Umbilical Retention and Release Mechanism

NASA Technical Reports Server (NTRS)

Delap, Damon C.; Glidden, Joel Micah; Lamoreaux, Christopher

2013-01-01

The Orion CSM umbilical retention and release mechanism supports and protects all of the cross-module commodities between the spacecrafts crew and service modules. These commodities include explosive transfer lines, wiring for power and data, and flexible hoses for ground purge and life support systems. The mechanism employs a single separation interface which is retained with pyrotechnically actuated separation bolts and supports roughly two dozen electrical and fluid connectors. When module separation is commanded, either for nominal on-orbit CONOPS or in the event of an abort, the mechanism must release the separation interface and sever all commodity connections within milliseconds of command receipt. There are a number of unique and novel aspects of the design solution developed by the Orion mechanisms team. The design is highly modular and can easily be adapted to other vehiclesmodules and alternate commodity sets. It will be flight tested during Orions Exploration Flight Test 1 (EFT-1) in 2014, and the Orion team anticipates reuse of the design for all future missions. The design packages fluid, electrical, and ordnance disconnects in a single separation interface. It supports abort separations even in cases where aerodynamic loading prevents the deployment of the umbilical arm. Unlike the Apollo CSM umbilical which was a destructive separation device, the Orion design is resettable and flight units can be tested for separation performance prior to flight.Initial development testing of the mechanisms separation interface resulted in binding failures due to connector misalignments. The separation interface was redesigned with a robust linear guide system, and the connector separation and boom deployment were separated into two discretely sequenced events. These changes addressed the root cause of the binding failure by providing better control of connector alignment. The new design was tuned and validated analytically via Monte Carlo simulation. The analytical validation was followed by a repeat of the initial test suite plus test cases at thermal extremes and test cases with imposed mechanical failures demonstrating fault tolerance. The mechanism was then exposed to the qualification vibration environment. Finally, separation testing was performed at full speed with live ordnance.All tests of the redesigned mechanism resulted in successful separation of the umbilical interface with adequate force margins and timing. The test data showed good agreement with the predictions of the Monte Carlo simulation. The simulation proved invaluable due to the number of variables affecting the separation and the uncertainty associated with each. The simulation allowed for rapid assessment of numerous trades and contingency scenarios, and can be easily reconfigured for varying commodity sets and connector layouts.

Use of multiresponse statistical techniques to optimize the separation of diosmin, hesperidin, diosmetin and hesperitin in different pharmaceutical preparations by high performance liquid chromatography with UV-DAD.

PubMed

Sammani, Mohamad Subhi; Clavijo, Sabrina; Portugal, Lindomar; Suárez, Ruth; Seddik, Hassan; Cerdà, Víctor

2017-05-15

A new method for the separation and determination of four flavonoids: hesperidin (HES), diosmin (DIO), hesperitin (HTIN), and diosmetin (DTIN) in pure form and pharmaceutical formulations has been developed by using high performance liquid chromatography (HPLC) with UV-DAD detection. Multivariate statistics (2 k full factorial and Box Behnken Designs) has been used for the multiresponse optimization of the chromatographic separation, which was completed in 22min, and carried out on a symmetry® C18 column (250×3mm; 5µm) as stationary phase. Separation was conducted by gradient elution mode using a mixture of methanol, acetonitrile and water pH: 2.5 (CH 3 COOH), as mobile phase. Analytes were separated setting the column at 22°C, with a flow rate of 0.58mLmin -1 and detected at 285nm. Under the optimized conditions, the flavonoids showed retention times of: 8.62, 11.53, 18.55 and 19.94min for HES, DIO, HTIN and DTIN, respectively. Limits of detection and quantification were <0.0156µgmL -1 and <0.100µgmL -1 , respectively. Linearity was achieved with good correlation coefficients values (r 2 =0.999; n=5). Intra-day and inter-day precision were found to be less than 3.44% (n=7). Finally, the proposed method was successfully applied to determine the target flavonoids in pharmaceutical preparations with satisfactory recoveries (between 95.2% and 107.9%), demonstrating that should also find application in the quality control, as well as in the pharmacokinetic studies of these drugs. Copyright © 2017 Elsevier B.V. All rights reserved.

Novel Polyimide Battery Separator Imbibed with Room-Temperature Ionic Liquids

NASA Technical Reports Server (NTRS)

Viggiano, Rocco; Nguyen, Baochau; Wu, James; Dai, Liming; Meador, Mary Ann

2017-01-01

The journey to Mars will require advancements in many existing technologies, including space power and energy storage systems. According to the 2015 NASA Technology Roadmaps, energy storage is a critical technology area to develop for both terrestrial as well as future long-term space missions. Currently, batteries represent one of the major areas in need of advancement, both in terms of energy density as well as safety. Recently, concerns regarding the fire safety of commercial lithium-ion batteries have prompted efforts to produce nonflammable battery components, namely the electrolyte and separator. Commercial lithium-ion batteries utilize polyolefin separators imbibed with a lithium salt dissolved in cyclic carbonates. This separator/electrolyte combination imparts good ionic conductivities in the range of 10(exp -2) to 10(exp -3) S/cm. However, the cyclic carbonates and polyolefin separator are inherently flammable. Room-temperature ionic liquids (RTILs) appear to be a safer alternative to cyclic carbonates. They offer good ionic conductivities, similar to those observed in cyclic carbonates, but are inherently nonvolatile and nonflammable giving them a safety advantage. Many promising RTILs for battery electrolytes are not compatible with commercial polyolefin separator materials. Polyimide aerogels possess an open-porous, fibrillar network architecture which offers a high degree of porosity (typically greater than 85 porous), required for lithium ion conduction, as well as good mechanical properties. Furthermore, these materials are compatible with all tested RTILs. By creating a polyimide gel and imbibing the gel with a RTIL containing a lithium salt instead of super critically drying them to form aerogels, a nonflammable separator/electrolyte system with conductivities in the range of 1x10(exp -3) S/cm has been demonstrated.

Mixed Matrix Membranes of Boron Icosahedron and Polymers of Intrinsic Microporosity (PIM-1) for Gas Separation

PubMed Central

Khan, Muntazim Munir; Shishatskiy, Sergey; Filiz, Volkan

2018-01-01

This work reports on the preparation and gas transport performance of mixed matrix membranes (MMMs) based on the polymer of intrinsic microporosity (PIM-1) and potassium dodecahydrododecaborate (K2B12H12) as inorganic particles (IPs). The effect of IP loading on the gas separation performance of these MMMs was investigated by varying the IP content (2.5, 5, 10 and 20 wt %) in a PIM-1 polymer matrix. The derived MMMs were characterized by scanning electron microscopy (SEM), thermogravimetric analysis (TGA), single gas permeation tests and sorption measurement. The PIM1/K2B12H12 MMMs show good dispersion of the IPs (from 2.5 to 10 wt %) in the polymer matrix. The gas permeability of PIM1/K2B12H12 MMMs increases as the loading of IPs increases (up to 10 wt %) without sacrificing permselectivity. The sorption isotherm in PIM-1 and PIM1/K2B12H12 MMMs demonstrate typical dual-mode sorption behaviors for the gases CO2 and CH4. PMID:29301312

Optical recognition of statistical patterns

NASA Astrophysics Data System (ADS)

Lee, S. H.

1981-12-01

Optical implementation of the Fukunaga-Koontz transform (FKT) and the Least-Squares Linear Mapping Technique (LSLMT) is described. The FKT is a linear transformation which performs image feature extraction for a two-class image classification problem. The LSLMT performs a transform from large dimensional feature space to small dimensional decision space for separating multiple image classes by maximizing the interclass differences while minimizing the intraclass variations. The FKT and the LSLMT were optically implemented by utilizing a coded phase optical processor. The transform was used for classifying birds and fish. After the F-K basis functions were calculated, those most useful for classification were incorporated into a computer generated hologram. The output of the optical processor, consisting of the squared magnitude of the F-K coefficients, was detected by a T.V. camera, digitized, and fed into a micro-computer for classification. A simple linear classifier based on only two F-K coefficients was able to separate the images into two classes, indicating that the F-K transform had chosen good features. Two advantages of optically implementing the FKT and LSLMT are parallel and real time processing.

Optical recognition of statistical patterns

NASA Technical Reports Server (NTRS)

Lee, S. H.

1981-01-01

Optical implementation of the Fukunaga-Koontz transform (FKT) and the Least-Squares Linear Mapping Technique (LSLMT) is described. The FKT is a linear transformation which performs image feature extraction for a two-class image classification problem. The LSLMT performs a transform from large dimensional feature space to small dimensional decision space for separating multiple image classes by maximizing the interclass differences while minimizing the intraclass variations. The FKT and the LSLMT were optically implemented by utilizing a coded phase optical processor. The transform was used for classifying birds and fish. After the F-K basis functions were calculated, those most useful for classification were incorporated into a computer generated hologram. The output of the optical processor, consisting of the squared magnitude of the F-K coefficients, was detected by a T.V. camera, digitized, and fed into a micro-computer for classification. A simple linear classifier based on only two F-K coefficients was able to separate the images into two classes, indicating that the F-K transform had chosen good features. Two advantages of optically implementing the FKT and LSLMT are parallel and real time processing.

Cellulosic fabrics printing with multifunctional encapsulated phthalocyanine pigment blue using phase separation method.

PubMed

Haroun, Ahmed A; Diab, H A; Hakeim, O A

2016-08-01

Aqueous dispersions of citric-acrylate (CAC) oligomer encapsulating C.I. Pigment Blue 15:3 (PB15:3) in the presence of glutaraldhyde were formulated using the phase separation method. FT-IR spectroscopy and centrifuge sedimentation are performed to confirm the encapsulation of pigment into CAC oligomer. The prepared capsules were characterized using thermal gravimetric analysis (TGA) and transmission electron microscope (TEM). The results revealed that the encapsulated pigment had a profound multifunctional impact and minimized the driving force of pigment printing on the cellulosic fabrics. Besides, the encapsulated pigment accelerated the pigment fixation on cellulosic fabrics without drying in one step and reduced the required amount of the binder, compared with the control sample. Furthermore, the printed fabrics exhibited good antibacterial performance against both Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). The presence of the crosslinker could be stabilized the encapsulated pigment on the cellulosic fabrics. Moreover, the light and washing fastness for the printed fabrics using encapsulated pigment are higher than that in case of using control samples. Copyright © 2016 Elsevier Ltd. All rights reserved.

[Separation of catechins and caffeine in tea polyphenol by isocratic elution high performance liquid chromatography].

PubMed

Tang, G Y; Wu, H J; Wu, L; Li, Z J; Yao, Y G

2001-05-01

The catechins, particularly in green tea, have been found to possess anti-mutagenic and anti-tumorigenic properties. As each catechin possesses distinct properties, a simple and rapid method that could be used for analysis of individual catechins in a complex mixture would be necessary. A relatively simple and rapid method for simultaneous separation of five catechins and caffeine in tea polyphenol by isocratic elution high performance liquid chromatography has been developed. The analysis could be finished within 30 min. They were measured using Resolve C18 column (at 43 degrees C) and UV detector (at 280 nm), water-85% phosphoric acid aqueous solution-acetonitrile-dimethyl formamide(DMF) (859:1:120:20, V/V) as mobile phase. There was a good linear relationship between the content of component and its peak area for catechins and caffeine, with the correlation coefficients of 0.9992-0.9999. The average recoveries (n = 5) were 83.33%-104.42%, and the relative standard deviations (n = 6) were 0.74%-1.43%. The effect of concentration of DMF in mobile phase was studied.

Enantioselective determination of metconazole in multi matrices by high-performance liquid chromatography.

PubMed

He, Rujian; Fan, Jun; Tan, Qi; Lai, Yecai; Chen, Xiaodong; Wang, Tai; Jiang, Ying; Zhang, Yaomou; Zhang, Weiguang

2018-02-01

A reliable and effective HPLC analytical method has been developed to stereoselectively quantify metconazole in soil and flour matrices. Effects of polysaccharide chiral stationary phase, type and content of alcoholic modifier on separation of racemic metconazole have been discussed in detail. Resolution and quantitative determination of metconazole stereoisomers were performed by using an Enantiopak OD column, with the n-hexane-ethanol mixture (97:3, v/v) at the flow rate of 1.0mL/min. Then, extraction and cleanup procedures followed by the modified QuEChERS (quick, easy, cheap, effective, rugged and safe) method were used for metconazole racemate in soil and flour matrices. The residual analysis method was validated. Good linearity (R 2 ≥ 0.9997) and recoveries (94.98-104.89%, RSD ≤ 2.0%) for four metconazole stereoisomers were obtained. In brief, this proposed method showed good accuracy and precision, which might be applied in enantioselective determination, residual quantitative analysis, and degradation of metconazole in food and environmental matrices. Copyright © 2017 Elsevier B.V. All rights reserved.

Generation of non-genomic oligonucleotide tag sequences for RNA template-specific PCR

PubMed Central

Pinto, Fernando Lopes; Svensson, Håkan; Lindblad, Peter

2006-01-01

Background In order to overcome genomic DNA contamination in transcriptional studies, reverse template-specific polymerase chain reaction, a modification of reverse transcriptase polymerase chain reaction, is used. The possibility of using tags whose sequences are not found in the genome further improves reverse specific polymerase chain reaction experiments. Given the absence of software available to produce genome suitable tags, a simple tool to fulfill such need was developed. Results The program was developed in Perl, with separate use of the basic local alignment search tool, making the tool platform independent (known to run on Windows XP and Linux). In order to test the performance of the generated tags, several molecular experiments were performed. The results show that Tagenerator is capable of generating tags with good priming properties, which will deliberately not result in PCR amplification of genomic DNA. Conclusion The program Tagenerator is capable of generating tag sequences that combine genome absence with good priming properties for RT-PCR based experiments, circumventing the effects of genomic DNA contamination in an RNA sample. PMID:16820068

Cluster analysis of European Y-chromosomal STR haplotypes using the discrete Laplace method.

PubMed

Andersen, Mikkel Meyer; Eriksen, Poul Svante; Morling, Niels

2014-07-01

The European Y-chromosomal short tandem repeat (STR) haplotype distribution has previously been analysed in various ways. Here, we introduce a new way of analysing population substructure using a new method based on clustering within the discrete Laplace exponential family that models the probability distribution of the Y-STR haplotypes. Creating a consistent statistical model of the haplotypes enables us to perform a wide range of analyses. Previously, haplotype frequency estimation using the discrete Laplace method has been validated. In this paper we investigate how the discrete Laplace method can be used for cluster analysis to further validate the discrete Laplace method. A very important practical fact is that the calculations can be performed on a normal computer. We identified two sub-clusters of the Eastern and Western European Y-STR haplotypes similar to results of previous studies. We also compared pairwise distances (between geographically separated samples) with those obtained using the AMOVA method and found good agreement. Further analyses that are impossible with AMOVA were made using the discrete Laplace method: analysis of the homogeneity in two different ways and calculating marginal STR distributions. We found that the Y-STR haplotypes from e.g. Finland were relatively homogeneous as opposed to the relatively heterogeneous Y-STR haplotypes from e.g. Lublin, Eastern Poland and Berlin, Germany. We demonstrated that the observed distributions of alleles at each locus were similar to the expected ones. We also compared pairwise distances between geographically separated samples from Africa with those obtained using the AMOVA method and found good agreement. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Recurrent Neural Networks With Auxiliary Memory Units.

PubMed

Wang, Jianyong; Zhang, Lei; Guo, Quan; Yi, Zhang

2018-05-01

Memory is one of the most important mechanisms in recurrent neural networks (RNNs) learning. It plays a crucial role in practical applications, such as sequence learning. With a good memory mechanism, long term history can be fused with current information, and can thus improve RNNs learning. Developing a suitable memory mechanism is always desirable in the field of RNNs. This paper proposes a novel memory mechanism for RNNs. The main contributions of this paper are: 1) an auxiliary memory unit (AMU) is proposed, which results in a new special RNN model (AMU-RNN), separating the memory and output explicitly and 2) an efficient learning algorithm is developed by employing the technique of error flow truncation. The proposed AMU-RNN model, together with the developed learning algorithm, can learn and maintain stable memory over a long time range. This method overcomes both the learning conflict problem and gradient vanishing problem. Unlike the traditional method, which mixes the memory and output with a single neuron in a recurrent unit, the AMU provides an auxiliary memory neuron to maintain memory in particular. By separating the memory and output in a recurrent unit, the problem of learning conflicts can be eliminated easily. Moreover, by using the technique of error flow truncation, each auxiliary memory neuron ensures constant error flow during the learning process. The experiments demonstrate good performance of the proposed AMU-RNNs and the developed learning algorithm. The method exhibits quite efficient learning performance with stable convergence in the AMU-RNN learning and outperforms the state-of-the-art RNN models in sequence generation and sequence classification tasks.

Vortex- and CO2 -gas-assisted liquid-liquid microextraction with salt addition for the high-performance liquid chromatographic determination of furanic compounds in concentrated juices and dried fruits.

PubMed

Abu-Bakar, Nur-Bahiyah; Makahleh, Ahmad; Saad, Bahruddin

2016-03-01

A novel microextraction method based on vortex- and CO2 -assisted liquid-liquid microextraction with salt addition for the isolation of furanic compounds (5-hydroxymethyl-2-furaldehyde, 5-methyl-2-furaldehyde, 2-furaldehyde, 3-furaldehyde, 2-furoic and 3-furoic acids) was developed. Purging the sample with CO2 was applied after vortexing to enhance the phase separation and mass transfer of the analytes. The optimum extraction conditions were: extraction solvent (volume), propyl acetate (125 μL); sample pH, 2.4; vortexing time, 45 s; salt concentration, 25% w/v and purging time, 5 min. The analytes were separated using an ODS Hypersil C18 column (250×4.6 mm i.d, 5 μm) under gradient flow. The proposed method showed good linearities (r(2) >0.999), low detection limits (0.08-1.9 μg/L) and good recoveries (80.7-122%). The validated method was successfully applied for the determination of the furanic compounds in concentrated juice (mango, date, orange, pomegranate, roselle, mangosteen and soursop) and dried fruit (prune, date and apricot paste) samples. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Development and validation of a solid-phase extraction method coupled with HPLC-UV detection for the determination of biogenic amines in Chinese rice wine.

PubMed

Zhang, Ying; Li, Yan; Zhu, Xiao-Juan; Li, Min; Chen, Hao-Yu; Lv, Xiao-Ling; Zhang, Jian

2017-07-01

A reliable and accurate method for the determination of seven biogenic amines (BAs) was developed and validated with Chinese rice wine samples. The BAs were derivatised with dansyl chloride, cleaned up using solid-phase extraction (SPE) and separated by high-performance liquid chromatography (HPLC) coupled with ultraviolet (UV) detection. The optimised derivatisation reaction, conducted at pH 9.6 and 60°C for 30 min, ensured baseline separation and peak symmetry for each BA. SPE clean-up using Oasis MCX cartridges yielded good recovery rates for all BAs and effectively reduced matrix effects. The developed method shows good linearity with determination coefficients of more than 0.9989 over a concentration range of 0.1-100 mg l -1 . The limits of detection (LODs) for the investigated BAs ranged from 2.07 to 5.56 µg l -1 . The intra- and inter-day relative standard deviations (RSDs) ranged from 0.86% to 3.81% and from 2.13% to 3.82%, respectively. Spiking experiments showed that the overall recovery rates ranged from 85% to 113%. Thus, the proposed method was demonstrated as being suitable for simultaneous detection, with accurate and precise quantification, of BAs in Chinese rice wine.

F γ: A new observable for photon-hadron discrimination in hybrid air shower events

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

Niechciol, M.; Risse, M.; Ruehl, P.

To semore » arch for ultra-high-energy photons in primary cosmic rays, air shower observables are needed that allow a good separation between primary photons and primary hadrons. In this paper, we present a new observable, F γ, which can be extracted from ground-array data in hybrid events, where simultaneous measurements of the longitudinal and the lateral shower profile are performed. The observable is based on a template fit to the lateral distribution measured by the ground array with the template taking into account the complementary information from the measurement of the longitudinal profile, i.e. the primary energy and the geometry of the shower. F γ shows a very good photon-hadron separation, which is even superior to the separation given by the well-known X max observable (the atmospheric depth of the shower maximum). At energies around 1 EeV (10 EeV), F γ provides a background rejection better than 97.8 % (99.9 %) at a signal efficiency of 50 %. Advantages of the observable F γ are its technical stability with respect to irregularities in the ground array (i.e. missing or temporarily non-operating stations) and that it can be applied over the full energy range accessible to the air shower detector, down to its threshold energy. Finally and furthermore, F γ complements nicely to X max such that both observables can well be combined to achieve an even better discrimination power, exploiting the rich information available in hybrid events.« less

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.

F γ: A new observable for photon-hadron discrimination in hybrid air shower events

DOE PAGES

Niechciol, M.; Risse, M.; Ruehl, P.; ...

2017-10-21

To semore » arch for ultra-high-energy photons in primary cosmic rays, air shower observables are needed that allow a good separation between primary photons and primary hadrons. In this paper, we present a new observable, F γ, which can be extracted from ground-array data in hybrid events, where simultaneous measurements of the longitudinal and the lateral shower profile are performed. The observable is based on a template fit to the lateral distribution measured by the ground array with the template taking into account the complementary information from the measurement of the longitudinal profile, i.e. the primary energy and the geometry of the shower. F γ shows a very good photon-hadron separation, which is even superior to the separation given by the well-known X max observable (the atmospheric depth of the shower maximum). At energies around 1 EeV (10 EeV), F γ provides a background rejection better than 97.8 % (99.9 %) at a signal efficiency of 50 %. Advantages of the observable F γ are its technical stability with respect to irregularities in the ground array (i.e. missing or temporarily non-operating stations) and that it can be applied over the full energy range accessible to the air shower detector, down to its threshold energy. Finally and furthermore, F γ complements nicely to X max such that both observables can well be combined to achieve an even better discrimination power, exploiting the rich information available in hybrid events.« less

Ordered mesoporous silica functionalized with β-cyclodextrin derivative for stereoisomer separation of flavanones and flavanone glycosides by nano-liquid chromatography and capillary electrochromatography.

PubMed

Silva, Mariana; Pérez-Quintanilla, Damián; Morante-Zarcero, Sonia; Sierra, Isabel; Marina, María Luisa; Aturki, Zeineb; Fanali, Salvatore

2017-03-24

In this paper a chiral stationary phase (CSP) was prepared by the immobilization of a β-CD derivative (3,5-dimethylphenylcarbamoylated β-CD) onto the surface of amino-functionalized spherical ordered mesoporous silica (denoted as SM) via a urea linkage using the Staudinger reaction. The CSP was packed into fused silica capillaries 100μm I.D. and evaluated by means of nano-liquid chromatography (nano-LC) and capillary electrochromatography (CEC) using model compounds for the enantio- and the diastereomeric separation. The compounds flavanone, 2'-hydroxyflavanone, 4'-hydroxyflavanone, 6-hydroxyflavanone, 4'-methoxyflavanone, 7-methoxyflavanone, hesperetin, hesperidin, naringenin, and naringin were studied using reversed and polar organic elution modes. Baseline stereoisomer resolution and good results in terms of peak efficiency and short analysis time of all studied flavonoids and flavanones glycosides were achieved in reversed phase mode, using as mobile phase a mixture of MeOH/H 2 O, 10mM ammonium acetate pH 4.5 at different ratios. For the polar organic mode using 100% of MeOH as mobile phase, the CSP showed better performances and the baseline chiral separation of several studied compounds occurred in an analysis time of less than 10min. Good results were also achieved by CEC employing two different mobile phases. The use of MeOH/H 2 O, 5mM ammonium acetate buffer pH 6.0 (90/10, v/v) was very effective for the chiral resolution of flavanone and its methoxy and hydroxy derivatives. Copyright © 2017 Elsevier B.V. All rights reserved.

Biomass-based palm shell activated carbon and palm shell carbon molecular sieve as gas separation adsorbents.

PubMed

Sethupathi, Sumathi; Bashir, Mohammed Jk; Akbar, Zinatizadeh Ali; Mohamed, Abdul Rahman

2015-04-01

Lignocellulosic biomass has been widely recognised as a potential low-cost source for the production of high added value materials and proved to be a good precursor for the production of activated carbons. One of such valuable biomasses used for the production of activated carbons is palm shell. Palm shell (endocarp) is an abundant by-product produced from the palm oil industries throughout tropical countries. Palm shell activated carbon and palm shell carbon molecular sieve has been widely applied in various environmental pollution control technologies, mainly owing to its high adsorption performance, well-developed porosity and low cost, leading to potential applications in gas-phase separation using adsorption processes. This mini-review represents a comprehensive overview of the palm shell activated carbon and palm shell carbon molecular sieve preparation method, physicochemical properties and feasibility of palm shell activated carbon and palm shell carbon molecular sieve in gas separation processes. Some of the limitations are outlined and suggestions for future improvements are pointed out. © The Author(s) 2015.

Numerical aspects and implementation of a two-layer zonal wall model for LES of compressible turbulent flows on unstructured meshes

NASA Astrophysics Data System (ADS)

Park, George Ilhwan; Moin, Parviz

2016-01-01

This paper focuses on numerical and practical aspects associated with a parallel implementation of a two-layer zonal wall model for large-eddy simulation (LES) of compressible wall-bounded turbulent flows on unstructured meshes. A zonal wall model based on the solution of unsteady three-dimensional Reynolds-averaged Navier-Stokes (RANS) equations on a separate near-wall grid is implemented in an unstructured, cell-centered finite-volume LES solver. The main challenge in its implementation is to couple two parallel, unstructured flow solvers for efficient boundary data communication and simultaneous time integrations. A coupling strategy with good load balancing and low processors underutilization is identified. Face mapping and interpolation procedures at the coupling interface are explained in detail. The method of manufactured solution is used for verifying the correct implementation of solver coupling, and parallel performance of the combined wall-modeled LES (WMLES) solver is investigated. The method has successfully been applied to several attached and separated flows, including a transitional flow over a flat plate and a separated flow over an airfoil at an angle of attack.

Gram scale synthesis of Fe/Fe xO y core–shell nanoparticles and their incorporation into matrix-free superparamagnetic nanocomposites

DOE PAGES

Watt, John Daniel; Bleier, Grant C.; Romero, Zachary William; ...

2018-05-15

In this paper, significant reductions recently seen in the size of wide-bandgap power electronics have not been accompanied by a relative decrease in the size of the corresponding magnetic components. To achieve this, a new generation of materials with high magnetic saturation and permeability are needed. Here, we develop gram-scale syntheses of superparamagnetic Fe/Fe xO y core–shell nanoparticles and incorporate them as the magnetic component in a strongly magnetic nanocomposite. Nanocomposites are typically formed by the organization of nanoparticles within a polymeric matrix. However, this approach can lead to high organic fractions and phase separation; reducing the performance of themore » resulting material. Here, we form aminated nanoparticles that are then cross-linked using epoxy chemistry. The result is a magnetic nanoparticle component that is covalently linked and well separated. By using this ‘matrix-free’ approach, we can substantially increase the magnetic nanoparticle fraction, while still maintaining good separation, leading to a superparamagnetic nanocomposite with strong magnetic properties.« less

Gram scale synthesis of Fe/Fe xO y core–shell nanoparticles and their incorporation into matrix-free superparamagnetic nanocomposites

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

Watt, John Daniel; Bleier, Grant C.; Romero, Zachary William

In this paper, significant reductions recently seen in the size of wide-bandgap power electronics have not been accompanied by a relative decrease in the size of the corresponding magnetic components. To achieve this, a new generation of materials with high magnetic saturation and permeability are needed. Here, we develop gram-scale syntheses of superparamagnetic Fe/Fe xO y core–shell nanoparticles and incorporate them as the magnetic component in a strongly magnetic nanocomposite. Nanocomposites are typically formed by the organization of nanoparticles within a polymeric matrix. However, this approach can lead to high organic fractions and phase separation; reducing the performance of themore » resulting material. Here, we form aminated nanoparticles that are then cross-linked using epoxy chemistry. The result is a magnetic nanoparticle component that is covalently linked and well separated. By using this ‘matrix-free’ approach, we can substantially increase the magnetic nanoparticle fraction, while still maintaining good separation, leading to a superparamagnetic nanocomposite with strong magnetic properties.« less

Sub-minute method for simultaneous determination of aspartame, cyclamate, acesulfame-K and saccharin in food and pharmaceutical samples by capillary zone electrophoresis.

PubMed

Vistuba, Jacqueline Pereira; Dolzan, Maressa Danielli; Vitali, Luciano; de Oliveira, Marcone Augusto Leal; Micke, Gustavo Amadeu

2015-05-29

This paper reports the development of a sub-minute separation method by capillary zone electrophoresis for the determination of aspartame, cyclamate, acesulfame-K and saccharin in food products and pharmaceutical samples. Separations were performed in a fused uncoated silica capillary with UV detection at 220nm. Samples and standards were injected hydrodynamically using the short-end injection procedure. The electrophoretic system was operated under constant voltage of -30kV. The background electrolyte was composed of 45mmolL(-1) 2-amino-2-(hydroxymethyl)-1,3-propanediol and 15mmolL(-1) benzoic acid at pH 8.4. The separation time for all analytes was less than 1min. Evaluation of analytical parameters of the method showed good linearity (r(2)>0.9972), limit of detection of 3.3-6.4mgL(-1), intermediate precision better than 9.75% (peak area of sample) and recovery in the range of 91-117%. Copyright © 2015 Elsevier B.V. All rights reserved.

The effect of geometry and operation conditions on the performance of a gas-liquid cylindrical cyclone separator with new structure

NASA Astrophysics Data System (ADS)

Han, Qing; Zhang, Chi; Xu, Bo; Chen, Jiangping

2013-07-01

The hydrodynamic flow behavior, effects of geometry and working conditions of a gas-liquid cylindrical cyclone separator with a new structure are investigated by computational fluid dynamic and experiment. Gas liquid cylindrical cyclone separator is widely used in oil industry, refrigeration system because of its simple structure, high separating efficiency, little maintenance and no moving parts nor internal devices. In this work, a gas liquid cylindrical cyclone separator with new structure used before evaporator in refrigeration system can remove the vapor from the mixture and make evaporator compact by improving its heat exchange efficiency with the lower inlet quality. It also decreases evaporator pressure drop and reduces compressor work. The two pipes are placed symmetrically which makes each of them can be treated as inlet. It means when the fluids flow reverse, the separator performance will not be influence. Four samples with different geometry parameters are tested by experiment with different inlet quality (0.18-0.33), inlet mass flow rate (65-100kg/h). Compared with the experimental data, CFD simulation results show a good agreement. Eulerian multiphase model and Reynolds Stress Turbulence model are applied in the CFD simulation and obtained the inner flow field such as phase path lines, tangential velocity profiles and pressure and volume of fraction distribution contours. The separator body diameter (24, 36, 48mm) and inlet diameter (3.84, 4.8, 5.76mm) decide the maximum tangential velocity which results in the centrifugal force. The tangential velocity profiles are simulated and compared among different models. The higher tangential velocity makes higher quality of gas outlet but high pressure drop at the same time. Decreasing the inlet diameter increases quality of gas outlet pipe and pressure drop. High gas outlet quality is cost at high pressure drop. Increasing of separator diameter makes gas outlet quality increase first and then decrease but the pressure drop decreases all the way. The offset (0, 2.4, 3.6mm) of gas outlet is an insensitive factor which influences the quality and pressure drop little.

An innovative monolithic zwitterionic stationary phase for the separation of phenolic acids in coffee bean extracts by capillary electrochromatography.

PubMed

Murauer, Adele; Bakry, Rania; Schottenberger, Herwig; Huck, Christian; Ganzera, Markus

2017-04-22

A methacrylate based monolith, containing the innovative zwitterionic monomer (3-allyl-1-imidazol)propane sulfonate, was prepared in 100 μm I.D. silica capillaries by UV initiated photo-polymerization. Composition of the porogen, i.e. a mixture of 1-propanol, 1,4 butanediol and water, was of great importance to obtain a homogeneous monolith with satisfactory permeability and good electrochromatographic performance. Morphology of the stationary phase was studied in Scanning Electron Microscopy and IR experiments, which revealed a good attachment to the capillary wall, flowthrough-pores in the range of 0.5-2 μm, and a continuous monolithic structure. The developed material was well suited for the analysis of six common phenolic acids (salicylic, cinnamic, syringic, rosmarinic, caffeic and chlorogenic acid) by CEC. Their separation was possible in less than 8 min with a mobile phase comprising a 12 mM aqueous ammonium acetate solution with pH 8.5 and acetonitrile, at an applied voltage of - 20 kV. The developed method was validated (R 2  ≥ 0.995; LOD ≤ 3.9 μg mL -1 , except for salicylic acid; recovery rates from 94 to 104%) and successfully used for the determination of phenolic acids in Coffea arabica samples. All of them contained cinnamic, syringic and caffeic acid, however only in unroasted coffee beans chlorogenic acid (0.06%) was found. The quantitative results were in good agreement to reported literature data. Copyright © 2017 The Author(s). Published by Elsevier B.V. All rights reserved.

Study of neutron generation in the compact tokamak TUMAN-3M in support of a tokamak-based fusion neutron source

NASA Astrophysics Data System (ADS)

Kornev, V. A.; Askinazi, L. G.; Belokurov, A. A.; Chernyshev, F. V.; Lebedev, S. V.; Melnik, A. D.; Shabelsky, A. A.; Tukachinsky, A. S.; Zhubr, N. A.

2017-12-01

The paper presents DD neutron flux measurements in neutron beam injection (NBI) experiments aimed at the optimization of target plasma and heating beam parameters to achieve maximum neutron flux in the TUMAN-3M compact tokamak. Two ion sources of different design were used, which allowed the separation of the beam’s energy and power influence on the neutron rate. Using the database of experiments performed with the two ion sources, an empirical scaling was derived describing the neutron rate dependence on the target plasma and heating beam parameters. Numerical modeling of the neutron rate in the NBI experiments performed using the ASTRA transport code showed good agreement with the scaling.

Positivity-preserving well-balanced discontinuous Galerkin methods for the shallow water flows in open channels

NASA Astrophysics Data System (ADS)

Qian, Shouguo; Li, Gang; Shao, Fengjing; Xing, Yulong

2018-05-01

We construct and study efficient high order discontinuous Galerkin methods for the shallow water flows in open channels with irregular geometry and a non-flat bottom topography in this paper. The proposed methods are well-balanced for the still water steady state solution, and can preserve the non-negativity of wet cross section numerically. The well-balanced property is obtained via a novel source term separation and discretization. A simple positivity-preserving limiter is employed to provide efficient and robust simulations near the wetting and drying fronts. Numerical examples are performed to verify the well-balanced property, the non-negativity of the wet cross section, and good performance for both continuous and discontinuous solutions.

Fame and obsolescence: Disentangling growth and aging dynamics of patent citations.

PubMed

Higham, K W; Governale, M; Jaffe, A B; Zülicke, U

2017-04-01

We present an analysis of citations accrued over time by patents granted by the United States Patent and Trademark Office in 1998. In contrast to previous studies, a disaggregation by technology category is performed, and exogenously caused citation-number growth is controlled for. Our approach reveals an intrinsic citation rate that clearly separates into an-in the long run, exponentially time-dependent-aging function and a completely time-independent preferential-attachment-type growth kernel. For the general case of such a separable citation rate, we obtain the time-dependent citation distribution analytically in a form that is valid for any functional form of its aging and growth parts. Good agreement between theory and long-time characteristics of patent-citation data establishes our work as a useful framework for addressing still open questions about knowledge-propagation dynamics, such as the observed excess of citations at short times.

Automated object-based classification of rain-induced landslides with VHR multispectral images in Madeira Island

NASA Astrophysics Data System (ADS)

Heleno, S.; Matias, M.; Pina, P.; Sousa, A. J.

2015-09-01

A method for semi-automatic landslide detection, with the ability to separate source and run-out areas, is presented in this paper. It combines object-based image analysis and a Support Vector Machine classifier on a GeoEye-1 multispectral image, sensed 3 days after the major damaging landslide event that occurred in Madeira island (20 February 2010), with a pre-event LIDAR Digital Elevation Model. The testing is developed in a 15 km2-wide study area, where 95 % of the landslides scars are detected by this supervised approach. The classifier presents a good performance in the delineation of the overall landslide area. In addition, fair results are achieved in the separation of the source from the run-out landslide areas, although in less illuminated slopes this discrimination is less effective than in sunnier east facing-slopes.

Hand-held analyser based on microchip electrophoresis with contactless conductivity detection for measurement of chemical warfare agent degradation products

NASA Astrophysics Data System (ADS)

Duran, Karolina-Petkovic; Zhu, Yonggang; Chen, Chuanpin; Swallow, Anthony; Stewart, Robert; Hoobin, Pam; Leech, Patrick; Ovenden, Simon

2008-12-01

This paper reports on the development of a hand-held device for on-site detection of organophosphonate nerve agent degradation products. This field-deployable analyzer relies on efficient microchip electrophoresis separation of alkyl methylphosphonic acids and their sensitive contactless conductivity detection. Miniaturized, low-powered design is coupled with promising analytical performance for separating the breakdown products of chemical warfare agents such as Soman, Sarin and VX . The detector has a detection limit of about 10 μg/mL and has a good linear response in the range 10-300 μg/mL concentration range. Applicability to environmental samples is demonstrated .The new hand-held analyzer offers great promise for converting conventional ion chromatography or capillary electrophoresis sophisticated systems into a portable forensic laboratory for faster, simpler and more reliable on-site screening.

Model and particle-in-cell simulation of ion energy distribution in collisionless sheath

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

Zhou, Zhuwen, E-mail: zzwwdxy@gznc.edu.cn; Key Laboratory of Photoelectron Materials Design and Simulation in Guizhou Province, Guiyang 550018; Scientific Research Innovation Team in Plasma and Functional Thin Film Materials in Guizhou Province, Guiyang 550018

2015-06-15

In this paper, we propose a self-consistent theoretical model, which is described by the ion energy distributions (IEDs) in collisionless sheaths, and the analytical results for different combined dc/radio frequency (rf) capacitive coupled plasma discharge cases, including sheath voltage errors analysis, are compared with the results of numerical simulations using a one-dimensional plane-parallel particle-in-cell (PIC) simulation. The IEDs in collisionless sheaths are performed on combination of dc/rf voltage sources electrodes discharge using argon as the process gas. The incident ions on the grounded electrode are separated, according to their different radio frequencies, and dc voltages on a separated electrode, themore » IEDs, and widths of energy in sheath and the plasma sheath thickness are discussed. The IEDs, the IED widths, and sheath voltages by the theoretical model are investigated and show good agreement with PIC simulations.« less

Analysis and enhancement of astaxanthin accumulation in Haematococcus pluvialis.

PubMed

Orosa, M; Franqueira, D; Cid, A; Abalde, J

2005-02-01

The green microalga Haematococcus pluvialis was cultured with different concentrations of NaNO(3) to determine the effect on cell growth and astaxanthin accumulation. The optimum nitrate concentration to obtain astaxanthin and to avoid the cessation of cell division was 0.15 g/l NaNO(3). The ratio chlorophyll a/total carotenoids proved a good physiological indicator of nitrogen deficiency in the cell. The effect of different carbon sources, malonate and acetate, on astaxanthin accumulation was also studied; up to 13 times more carotenoids per cell were accumulated in cultures with malonate than in cultures without this compound. The pigment analysis was performed by a new low toxicity HPLC method capable of separating chlorophylls a and b, carotenes and xanthophylls in a short-period of time, using low volumes of solvents and with an economical price. With this method even echinenone was separated, which had been unsuccessful by any other method.

A collaborative scheduling model for the supply-hub with multiple suppliers and multiple manufacturers.

PubMed

Li, Guo; Lv, Fei; Guan, Xu

2014-01-01

This paper investigates a collaborative scheduling model in the assembly system, wherein multiple suppliers have to deliver their components to the multiple manufacturers under the operation of Supply-Hub. We first develop two different scenarios to examine the impact of Supply-Hub. One is that suppliers and manufacturers make their decisions separately, and the other is that the Supply-Hub makes joint decisions with collaborative scheduling. The results show that our scheduling model with the Supply-Hub is a NP-complete problem, therefore, we propose an auto-adapted differential evolution algorithm to solve this problem. Moreover, we illustrate that the performance of collaborative scheduling by the Supply-Hub is superior to separate decision made by each manufacturer and supplier. Furthermore, we also show that the algorithm proposed has good convergence and reliability, which can be applicable to more complicated supply chain environment.

Asymmetric organic-inorganic hybrid membrane formation via block copolymer-nanoparticle co-assembly.

PubMed

Gu, Yibei; Dorin, Rachel M; Wiesner, Ulrich

2013-01-01

A facile method for forming asymmetric organic-inorganic hybrid membranes for selective separation applications is developed. This approach combines co-assembly of block copolymer (BCP) and inorganic nanoparticles (NPs) with non-solvent induced phase separation. The method is successfully applied to two distinct molar mass BCPs with different fractions of titanium dioxide (TiO2) NPs. The resulting hybrid membranes exhibit structural asymmetry with a thin nanoporous surface layer on top of a macroporous fingerlike support layer. Key parameters that dictate membrane surface morphology include the fraction of inorganics used and the length of time allowed for surface layer development. The resulting membranes exhibit both good selectivity and high permeability (3200 ± 500 Lm(-2) h(-1) bar(-1)). This fast and straightforward synthesis method for asymmetric hybrid membranes provides a new self-assembly platform upon which multifunctional and high-performance organic-inorganic hybrid membranes can be formed.

Growth and Morphology of Phase Separating Supercritical Fluids

NASA Technical Reports Server (NTRS)

Hegseth, John; Beysens, Daniel; Perrot, Francoise; Nikolayev, Vadim; Garrabos, Yves

1996-01-01

The scientific objective is to study the relation between the morphology and the growth kinetics of domains during phase separation. We know from previous experiments performed near the critical point of pure fluids and binary liquids that there are two simple growth laws at late times. The 'fast' growth appears when the volumes of the phases are nearly equal and the droplet pattern is interconnected. In this case the size of the droplets grows linearly in time. The 'slow' growth appears when the pattern of droplets embedded in the majority phase is disconnected. In this case the size of the droplets increases in proportion to time to the power 1/3. The volume fraction of the minority phase is a good candidate to determine this change of behavior. All previous attempts to vary the volume fraction in a single experimental cell have failed because of the extreme experimental difficulties.

Wall accumulation of bacteria with different motility patterns.

PubMed

Sartori, Paolo; Chiarello, Enrico; Jayaswal, Gaurav; Pierno, Matteo; Mistura, Giampaolo; Brun, Paola; Tiribocchi, Adriano; Orlandini, Enzo

2018-02-01

We systematically investigate the role of different swimming patterns on the concentration distribution of bacterial suspensions confined between two flat walls, by considering wild-type motility Escherichia coli and Pseudomonas aeruginosa, which perform Run and Tumble and Run and Reverse patterns, respectively. The experiments count motile bacteria at different distances from the bottom wall. In agreement with previous studies, an accumulation of motile bacteria close to the walls is observed. Different wall separations, ranging from 100 to 250μm, are tested. The concentration profiles result to be independent on the motility pattern and on the walls' separation. These results are confirmed by numerical simulations, based on a collection of self-propelled dumbbells-like particles interacting only through steric interactions. The good agreement with the simulations suggests that the behavior of the investigated bacterial suspensions is determined mainly by steric collisions and self-propulsion, as well as hydrodynamic interactions.

Wall accumulation of bacteria with different motility patterns

NASA Astrophysics Data System (ADS)

Sartori, Paolo; Chiarello, Enrico; Jayaswal, Gaurav; Pierno, Matteo; Mistura, Giampaolo; Brun, Paola; Tiribocchi, Adriano; Orlandini, Enzo

2018-02-01

We systematically investigate the role of different swimming patterns on the concentration distribution of bacterial suspensions confined between two flat walls, by considering wild-type motility Escherichia coli and Pseudomonas aeruginosa, which perform Run and Tumble and Run and Reverse patterns, respectively. The experiments count motile bacteria at different distances from the bottom wall. In agreement with previous studies, an accumulation of motile bacteria close to the walls is observed. Different wall separations, ranging from 100 to 250 μ m , are tested. The concentration profiles result to be independent on the motility pattern and on the walls' separation. These results are confirmed by numerical simulations, based on a collection of self-propelled dumbbells-like particles interacting only through steric interactions. The good agreement with the simulations suggests that the behavior of the investigated bacterial suspensions is determined mainly by steric collisions and self-propulsion, as well as hydrodynamic interactions.

Fame and obsolescence: Disentangling growth and aging dynamics of patent citations

NASA Astrophysics Data System (ADS)

Higham, K. W.; Governale, M.; Jaffe, A. B.; Zülicke, U.

2017-04-01

We present an analysis of citations accrued over time by patents granted by the United States Patent and Trademark Office in 1998. In contrast to previous studies, a disaggregation by technology category is performed, and exogenously caused citation-number growth is controlled for. Our approach reveals an intrinsic citation rate that clearly separates into an—in the long run, exponentially time-dependent—aging function and a completely time-independent preferential-attachment-type growth kernel. For the general case of such a separable citation rate, we obtain the time-dependent citation distribution analytically in a form that is valid for any functional form of its aging and growth parts. Good agreement between theory and long-time characteristics of patent-citation data establishes our work as a useful framework for addressing still open questions about knowledge-propagation dynamics, such as the observed excess of citations at short times.

A Collaborative Scheduling Model for the Supply-Hub with Multiple Suppliers and Multiple Manufacturers

PubMed Central

Lv, Fei; Guan, Xu

2014-01-01

This paper investigates a collaborative scheduling model in the assembly system, wherein multiple suppliers have to deliver their components to the multiple manufacturers under the operation of Supply-Hub. We first develop two different scenarios to examine the impact of Supply-Hub. One is that suppliers and manufacturers make their decisions separately, and the other is that the Supply-Hub makes joint decisions with collaborative scheduling. The results show that our scheduling model with the Supply-Hub is a NP-complete problem, therefore, we propose an auto-adapted differential evolution algorithm to solve this problem. Moreover, we illustrate that the performance of collaborative scheduling by the Supply-Hub is superior to separate decision made by each manufacturer and supplier. Furthermore, we also show that the algorithm proposed has good convergence and reliability, which can be applicable to more complicated supply chain environment. PMID:24892104

Controlled crosslinking of trimethylolpropane trimethacrylate for preparation of organic monolithic columns for capillary liquid chromatography.

PubMed

Gama, Mariana R; Aggarwal, Pankaj; Lee, Milton L; Bottoli, Carla B G

2017-11-01

Organic monolithic columns based on single crosslinking of trimethylolpropane trimethacrylate (TRIM) monomer were prepared in a single step by living/controlled free-radical polymerization. Full optimization of the preparation, such as using different percentages of TRIM and different amounts of radical promoter as well as various porogen solvents were explored. The resulting monolithic columns were characterized by scanning electronic microscopy and nitrogen sorption for structure morphology studies and surface area measurements, respectively. Using capillary liquid chromatography, 150 μm i.d. columns were applied to separate a mixture of small hydrophobic molecules. The results indicated that column performance is highly sensitive to the type and the amount of porogen solvents used in the polymerization mixture composition. Good resolution factors and methylene selectivity were obtained, indicating the promising potential of this material for capillary liquid chromatography separations. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

A novel octadecylsilane functionalized graphene oxide/silica composite stationary phase for high performance liquid chromatography.

PubMed

Liang, Xiaojing; Wang, Shuai; Liu, Shujuan; Liu, Xia; Jiang, Shengxiang

2012-08-01

An octadecylsilane functionalized graphene oxide/silica stationary phase was fabricated by assembling graphene oxide onto the silica particles through an amide bond and subsequent immobilization of octadecylsilane. The chromatographic properties of the stationary phase were investigated by reversed-phase chromatography with alkylbenzenes, polycyclic aromatic hydrocarbons, amines, and phenolic compounds as the analytes. All the compounds achieved good separation on the column. The comparison between a C18 commercial column and the new stationary phase indicated that the existence of π-electron system of graphene oxide allows π-π interaction between analyte and octadecylsilane functionalized graphene oxide/silica stationary phase except for hydrophobic interaction, while only hydrophobic interaction presented between analyte and C18 commercial column. This suggests that some analytes can be better separated on the octadecylsilane functionalized graphene oxide/silica column. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Pressure-assisted synthesis of HKUST-1 thin film on polymer hollow fiber at room temperature toward gas separation.

PubMed

Mao, Yiyin; Li, Junwei; Cao, Wei; Ying, Yulong; Sun, Luwei; Peng, Xinsheng

2014-03-26

The scalable fabrication of continuous and defect-free metal-organic framework (MOF) films on the surface of polymeric hollow fibers, departing from ceramic supported or dense composite membranes, is a huge challenge. The critical way is to reduce the growth temperature of MOFs in aqueous or ethanol solvents. In the present work, a pressure-assisted room temperature growth strategy was carried out to fabricate continuous and well-intergrown HKUST-1 films on a polymer hollow fiber by using solid copper hydroxide nanostrands as the copper source within 40 min. These HKUST-1 films/polyvinylidenefluoride (PVDF) hollow fiber composite membranes exhibit good separation performance for binary gases with selectivity 116% higher than Knudsen values via both inside-out and outside-in modes. This provides a new way to enable for scale-up preparation of HKUST-1/polymer hollow fiber membranes, due to its superior economic and ecological advantages.

Three-Dimensional Computational Model for Flow in an Over-Expanded Nozzle With Porous Surfaces

NASA Technical Reports Server (NTRS)

Abdol-Hamid, K. S.; Elmiligui, Alaa; Hunter, Craig A.; Massey, Steven J.

2006-01-01

A three-Dimensional computational model is used to simulate flow in a non-axisymmetric, convergent-divergent nozzle incorporating porous cavities for shock-boundary layer interaction control. The nozzle has an expansion ratio (exit area/throat area) of 1.797 and a design nozzle pressure ratio of 8.78. Flow fields for the baseline nozzle (no porosity) and for the nozzle with porous surfaces of 10% openness are computed for Nozzle Pressure Ratio (NPR) varying from 1.29 to 9.54. The three dimensional computational results indicate that baseline (no porosity) nozzle performance is dominated by unstable, shock-induced, boundary-layer separation at over-expanded conditions. For NPR less than or equal to 1.8, the separation is three dimensional, somewhat unsteady, and confined to a bubble (with partial reattachment over the nozzle flap). For NPR greater than or equal to 2.0, separation is steady and fully detached, and becomes more two dimensional as NPR increased. Numerical simulation of porous configurations indicates that a porous patch is capable of controlling off design separation in the nozzle by either alleviating separation or by encouraging stable separation of the exhaust flow. In the present paper, computational simulation results, wall centerline pressure, mach contours, and thrust efficiency ratio are presented, discussed and compared with experimental data. Results indicate that comparisons are in good agreement with experimental data. The three-dimensional simulation improves the comparisons for over-expanded flow conditions as compared with two-dimensional assumptions.

Development of a perfusion reversed-phase high performance liquid chromatography method for the characterisation of maize products using multivariate analysis.

PubMed

Rodriguez-Nogales, J M; Garcia, M C; Marina, M L

2006-02-03

A perfusion reversed-phase high performance liquid chromatography (RP-HPLC) method has been designed to allow rapid (3.4 min) separations of maize proteins with high resolution. Several factors, such as extraction conditions, temperature, detection wavelength and type and concentration of ion-pairing agent were optimised. A fine optimisation of the gradient elution was also performed by applying experimental design. Commercial maize products for human consumption (flours, precocked flours, fried snacks and extruded snacks) were characterised for the first time by perfusion RP-HPLC and their chromatographic profiles allowed a differentiation among products relating the different technological process used for their preparation. Furthermore, applying discriminant analysis makes it possible to group the samples according with the technological process suffered by maize products, obtaining a good prediction in 92% of the samples.

Experimental and Model Studies on Continuous Separation of 2-Phenylpropionic Acid Enantiomers by Enantioselective Liquid-Liquid Extraction in Centrifugal Contactor Separators.

PubMed

Feng, Xiaofeng; Tang, Kewen; Zhang, Pangliang; Yin, Shuangfeng

2016-03-01

Multistage enantioselective liquid-liquid extraction (ELLE) of 2-phenylpropionic acid (2-PPA) enantiomers using hydroxypropyl-β-cyclodextrin (HP-β-CD) as extractant was studied experimentally in a counter-current cascade of centrifugal contactor separators (CCSs). Performance of the process was evaluated by purity (enantiomeric excess, ee) and yield (Y). A multistage equilibrium model was established on the basis of single-stage model for chiral extraction of 2-PPA enantiomers and the law of mass conservation. A series of experiments on the extract phase/washing phase ratio (W/O ratio), extractant concentration, the pH value of aqueous phase, and the number of stages was conducted to verify the multistage equilibrium model. It was found that model predictions were in good agreement with the experimental results. The model was applied to predict and optimize the symmetrical separation of 2-PPA enantiomers. The optimal conditions for symmetric separation involves a W/O ratio of 0.6, pH of 2.5, and HP-β-CD concentration of 0.1 mol L(-1) at a temperature of 278 K, where eeeq (equal enantiomeric excess) can reach up to 37% and Yeq (equal yield) to 69%. By simulation and optimization, the minimum number of stages was evaluated at 98 and 106 for eeeq > 95% and eeeq > 97%. © 2016 Wiley Periodicals, Inc.

Elution-extrusion counter-current chromatography for the separation of two pairs of isomeric monoterpenes from Paeoniae Alba Radix.

PubMed

Chu, Chu; Zhang, Shidi; Tong, Shengqiang; Li, Xingnuo; Li, Qingyong; Yan, Jizhong

2015-09-01

In this work, a simple and efficient protocol for the rapid separation of two pairs of isomeric monoterpenes from Paeoniae Alba Radix was developed by combining macroporous resin and elution-extrusion counter-current chromatography. The crude extract was firstly subjected to a D101 macroporous resin column eluted with water and a series of different concentrations of ethanol. Then, effluents of 30 and 95% ethanol were collected as sample 1 and sample 2 for further counter-current chromatography purification. Finally, a pair of isomers, 96 mg of compound 1 and 48 mg of compound 2 with purities of 91.1 and 96.2%, respectively, was isolated from 200 mg of sample 1. The other pair of isomers, 14 mg of compound 3 and 8 mg of compound 4 with purities of 93.6 and 88.9%, respectively, was isolated from 48 mg of sample 2. Their purities were analyzed by high-performance liquid chromatography, and their chemical structures were identified by mass spectrometry and (1) H NMR spectroscopy. Compared to a normal counter-current chromatography separation, the separation time and solvent consumption of elution-extrusion counter-current chromatography were reduced while the resolutions were still good. The established protocol is promising for the separation of natural products with great disparity of content in herbal medicines. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Ion chromatography with the indirect ultraviolet detection of alkali metal ions and ammonium using imidazolium ionic liquid as ultraviolet absorption reagent and eluent.

PubMed

Liu, Yong-Qiang; Yu, Hong

2016-08-01

Indirect ultraviolet detection was conducted in ultraviolet-absorption-agent-added mobile phase to complete the detection of the absence of ultraviolet absorption functional group in analytes. Compared with precolumn derivatization or postcolumn derivatization, this method can be widely used, has the advantages of simple operation and good linear relationship. Chromatographic separation of Li(+) , Na(+) , K(+) , and NH4 (+) was performed on a carboxylic acid base cation exchange column using imidazolium ionic liquid/acid/organic solvent as the mobile phase, in which imidazolium ionic liquids acted as ultraviolet absorption reagent and eluting agent. The retention behaviors of four kinds of cations are discussed, and the mechanism of separation and detection are described. The main factors influencing the separation and detection were the background ultraviolet absorption reagent and the concentration of hydrogen ion in the ion chromatography-indirect ultraviolet detection. The successful separation and detection of Li(+) , Na(+) , K(+) , and NH4 (+) within 13 min was achieved using the selected chromatographic conditions, and the detection limits (S/N = 3) were 0.02, 0.11, 0.30, and 0.06 mg/L, respectively. A new separation and analysis method of alkali metal ions and ammonium by ion chromatography with indirect ultraviolet detection method was developed, and the application range of ionic liquid was expanded. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Differential analysis for the turbulent boundary layer on a compressor blade element (including boundary-layer separation)

NASA Technical Reports Server (NTRS)

Schmidt, J. F.; Todd, C. A.

1974-01-01

A two-dimensional differential analysis is developed to approximate the turbulent boundary layer on a compressor blade element with strong adverse pressure gradients, including the separated region with reverse flow. The predicted turbulent boundary layer thicknesses and velocity profiles are in good agreement with experimental data for a cascade blade, even in the separated region.

Simulation of Sweep-Jet Flow Control, Single Jet and Full Vertical Tail

NASA Technical Reports Server (NTRS)

Childs, Robert E.; Stremel, Paul M.; Garcia, Joseph A.; Heineck, James T.; Kushner, Laura K.; Storms, Bruce L.

2016-01-01

This work is a simulation technology demonstrator, of sweep jet flow control used to suppress boundary layer separation and increase the maximum achievable load coefficients. A sweep jet is a discrete Coanda jet that oscillates in the plane parallel to an aerodynamic surface. It injects mass and momentum in the approximate streamwise direction. It also generates turbulent eddies at the oscillation frequency, which are typically large relative to the scales of boundary layer turbulence, and which augment mixing across the boundary layer to attack flow separation. Simulations of a fluidic oscillator, the sweep jet emerging from a nozzle downstream of the oscillator, and an array of sweep jets which suppresses boundary layer separation are performed. Simulation results are compared to data from a dedicated validation experiment of a single oscillator and its sweep jet, and from a wind tunnel test of a full-scale Boeing 757 vertical tail augmented with an array of sweep jets. A critical step in the work is the development of realistic time-dependent sweep jet inflow boundary conditions, derived from the results of the single-oscillator simulations, which create the sweep jets in the full-tail simulations. Simulations were performed using the computational fluid dynamics (CFD) solver Overow, with high-order spatial discretization and a range of turbulence modeling. Good results were obtained for all flows simulated, when suitable turbulence modeling was used.

Enantiomeric separation of triazole fungicides with 3-μm and 5-μml particle chiral columns by reverse-phase high-performance liquid chromatography.

PubMed

Qiu, Jing; Dai, Shouhui; Zheng, Chuangmu; Yang, Shuming; Chai, Tingting; Bie, Mei

2011-07-01

This study used chiral columns packed with 3-μm and 5-μm particles to comparatively separate enantiomers of 9 triazole fungicides, and Lux Cellulose-1 columns with chiral stationary phase of cellulose-tris-(3,5-dimethylphenylcarbamate) were used on reverse-phase high-performance liquid chromatography with flow rates of 0.3 and 1.0 mL min(-1) for 3-μm and 5-μm columns, respectively. The (+)-enantiomers of hexaconazole (1), tetraconazole (4), myclobutanil (7), fenbuconazole (8) and the (-)-enantiomers of flutriafol (2), diniconazole (3), epoxiconazole (5), penconazole (6), triadimefon (9) were firstly eluted from both columns, the elution orders identified with an optical rotation detector didn't change with variety of column particles and mobile phases (acetronitrile/water and methanol/water). The plots of natural logarithms of the selectivity factors (ln α) for all fungicides except penconazole (6) versus the inverse of temperature (1/T) were linear in range of 5-40°C. The thermodynamic parameters (ΔH°, ΔS°, ΔΔH° and ΔΔS°) were calculated using Van't Hoff equations to understand the thermosynamic driving forces for enantioseparation. This work will be very helpful to obtain good enantiomeric separation and establish more efficient analytical method for triazole fungicides. Chirality, 2011. © 2011 Wiley-Liss, Inc. Copyright © 2011 Wiley-Liss, Inc.

Coupling nanoliter high-performance liquid chromatography to inductively coupled plasma mass spectrometry for arsenic speciation.

PubMed

Cheng, Heyong; Shen, Lihuan; Liu, Jinhua; Xu, Zigang; Wang, Yuanchao

2018-04-01

Nanoliter high-performance liquid chromatography shows low consumption of solvents and samples, offering one of the best choices for arsenic speciation in precious samples in combination with inuctively coupled plasma mass spectrometry. A systematic investigation on coupling nanoliter high-performance liquid chromatography to inductively coupled plasma mass spectrometry from instrument design to injected sample volume and mobile phase was performed in this study. Nanoflow mobile phase was delivered by flow splitting using a conventional high-pressure pump with reuse of mobile phase waste. Dead volume was minimized to 60 nL for the sheathless interface based on the previously developed nanonebulizer. Capillary columns for nanoliter high-performance liquid chromatography were found to be sensitive to sample loading volume. An apparent difference was also found between the mobile phases for nanoliter and conventional high-performance liquid chromatography. Baseline separation of arsenite, arsenate, monomethylarsenic, and dimethylarsenic was achieved within 11 min on a 15 cm C 18 capillary column and within 12 min on a 25 cm strong anion exchange column. Detection limits of 0.9-1.8 μg/L were obtained with precisions variable in the range of 1.6-4.2%. A good agreement between determined and certified values of a certified reference material of human urine (GBW 09115) validated its accuracy along with good recoveries (87-102%). © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Influence of birthweight on childhood balance: Evidence from two British birth cohorts.

PubMed

Okuda, Paola Matiko Martins; Swardfager, Walter; Ploubidis, George B; Pangelinan, Melissa; Cogo-Moreira, Hugo

2018-01-26

Birthweight is an important predictor of various fundamental aspects of childhood health and development. To examine the impact of birthweight on childhood balance performance classification and verify if this is replicable and consistent in different populations. Prospective birth cohort study. To describe heterogeneity in balance skills, latent class analyses were conducted separately with data from the 1958 National Child Development Study - NCDS (n = 12,778), and the 1970 British Cohort Study - BCS (n = 12,115). Four balance tasks for NCDS and five balance tasks for BCS. Birthweight was assessed as a predictor of balance skills. In both cohorts, two latent classes (good and poor balance skills) were identified. In both cohorts, higher birthweight was associated with a higher likelihood of having good balance skills. Boys were less likely to have good balance compared to girls. The results establish the reproducibility and consistency of the effect of birthweight on balance skills and point to early intervention for individuals with lower birthweight to mitigate the impact of motor impairment. Copyright © 2018 Elsevier B.V. All rights reserved.

Prediction of Classroom Reverberation Time using Neural Network

NASA Astrophysics Data System (ADS)

Liyana Zainudin, Fathin; Kadir Mahamad, Abd; Saon, Sharifah; Nizam Yahya, Musli

2018-04-01

In this paper, an alternative method for predicting the reverberation time (RT) using neural network (NN) for classroom was designed and explored. Classroom models were created using Google SketchUp software. The NN applied training dataset from the classroom models with RT values that were computed from ODEON 12.10 software. The NN was conducted separately for 500Hz, 1000Hz, and 2000Hz as absorption coefficient that is one of the prominent input variable is frequency dependent. Mean squared error (MSE) and regression (R) values were obtained to examine the NN efficiency. Overall, the NN shows a good result with MSE < 0.005 and R > 0.9. The NN also managed to achieve a percentage of accuracy of 92.53% for 500Hz, 93.66% for 1000Hz, and 93.18% for 2000Hz and thus displays a good and efficient performance. Nevertheless, the optimum RT value is range between 0.75 – 0.9 seconds.

Comparative evaluation of three shaft seals proposed for high performance turbomachinery

NASA Technical Reports Server (NTRS)

Hendricks, R. C.

1982-01-01

Experimental pressure profiles and leak rate characteristics for three shaft seal prototype model configurations proposed for the space shuttle turbopump were assessed in the concentric and fully eccentric, to point of rub, positions without the effects of rotation. The parallel-cylindrical configuration has moderate to good stiffness with a higher leak rate. It represents a simple concept, but for practical reasons and possible increases in stability, all such seals should be conical-convergent. The three-stepdown-sequential, parallel-cylindrical seal is converging and represents good to possible high stiffness when fluid separation occurs, with a significant decrease in leak rate. Such seals can be very effective. The three-stepdown-sequential labyrinth seal of 33-teeth (i.e., 12-11-10 teeth from inlet to exit) provides excellent leak control but usually has very poor stiffness, depending on cavity design. The seal is complex and not recommended for dynamic control.

Separation of mouse testis cells on a Celsep (TM) apparatus and their usefulness as a source of high molecular weight DNA or RNA

NASA Technical Reports Server (NTRS)

Wolgemuth, D. J.; Gizang-Ginsberg, E.; Engelmyer, E.; Gavin, B. J.; Ponzetto, C.

1985-01-01

The use of a self-contained unit-gravity cell separation apparatus for separation of populations of mouse testicular cells is described. The apparatus, a Celsep (TM), maximizes the unit area over which sedimentation occurs, reduces the amount of separation medium employed, and is quite reproducible. Cells thus isolated have been good sources for isolation of DNA, and notably, high molecular weight RNA.

Exoplanet Direct Imaging: Coronagraph Probe Mission Study EXO-C

NASA Technical Reports Server (NTRS)

Stapelfeldt, Karl R.

2013-01-01

Flagship mission for spectroscopy of ExoEarths is a long-term priority for space astrophysics (Astro2010). Requires 10(exp 10) contrast at 3 lambda/D separation, ( (is) greater than 10,000 times beyond HST performance) and large telescope (is) greater than 4m aperture. Big step. Mission for spectroscopy of giant planets and imaging of disks requires 10(exp 9) contrast at 3 lambda/D (already demonstrated in lab) and (is) approximately 1.5m telescope. Should be much more affordable, good intermediate step.Various PIs have proposed many versions of the latter mission 17 times since 1999; no unified approach.

[Determination of triterpenoic acids in fruits of Ziziphus jujuba using HPLC-MS with polymeric ODS column].

PubMed

Zhang, Yong; Zhou, An; Xie, Xiao-Mei

2013-03-01

A simple and sensitive method has been developed to simultaneously determine betunilic acid, oleanolic acid and ursolic acid in the fruits of Ziziphus jujuba from different regions by HPLC-MS. This HPLC assay was performed on PAH polymeric C18 bonded stationary phase column with mobile phase contained acetonitrile-water (90: 10) and with negative ESI detection mode. The developed approach was characterized by short time consumption for chromatographic separation, high sensitivity and good reliability so as to meet the requirements for rapid analysis of large-batch fruits of Z. jujuba from different habitats.

Large areal mass, flexible and free-standing reduced graphene oxide/manganese dioxide paper for asymmetric supercapacitor device.

PubMed

Sumboja, Afriyanti; Foo, Ce Yao; Wang, Xu; Lee, Pooi See

2013-05-28

Well-separated RGO sheets decorated with MnO2 nanoparticles facilitate easy access of the electrolyte ions to the high surface area of the paper electrode, enabling the fabrication of a thicker electrode with heavier areal mass and higher areal capacitance (up to 897 mF cm(-2) ). The electrochemical performance of the bent asymmetric device with a total active mass of 15 mg remains similar to the one in the flat configuration, demonstrating good mechanical robustness of the device. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

CFD Analysis of Turbo Expander for Cryogenic Refrigeration and Liquefaction Cycles

NASA Astrophysics Data System (ADS)

Verma, Rahul; Sam, Ashish Alex; Ghosh, Parthasarathi

Computational Fluid Dynamics analysis has emerged as a necessary tool for designing of turbomachinery. It helps to understand the various sources of inefficiency through investigation of flow physics of the turbine. In this paper, 3D turbulent flow analysis of a cryogenic turboexpander for small scale air separation was performed using Ansys CFX®. The turboexpander has been designed following assumptions based on meanlineblade generation procedure provided in open literature and good engineering judgement. Through analysis of flow field, modifications and further analysis required to evolve a more robust design procedure, have been suggested.

Fetal ECG extraction using independent component analysis by Jade approach

NASA Astrophysics Data System (ADS)

Giraldo-Guzmán, Jader; Contreras-Ortiz, Sonia H.; Lasprilla, Gloria Isabel Bautista; Kotas, Marian

2017-11-01

Fetal ECG monitoring is a useful method to assess the fetus health and detect abnormal conditions. In this paper we propose an approach to extract fetal ECG from abdomen and chest signals using independent component analysis based on the joint approximate diagonalization of eigenmatrices approach. The JADE approach avoids redundancy, what reduces matrix dimension and computational costs. Signals were filtered with a high pass filter to eliminate low frequency noise. Several levels of decomposition were tested until the fetal ECG was recognized in one of the separated sources output. The proposed method shows fast and good performance.

Saying Good-by: An Example of Using a Good-by Technique and Concomitant Psychodrama in the Resolving of Family Grief.

ERIC Educational Resources Information Center

Kaminski, Robert C.

A structured technique for saying "good-bye," or terminating a relationship, an important aspect of the therapeutic relationship, is presented. It consists of three distinct phases that are all dynamically interrelated, and can also be structured into separation caused by death. The technique is described in terms of three specific areas…

Impacts of Good Practices on Cognitive Development, Learning Orientations, and Graduate Degree Plans during the First Year of College

ERIC Educational Resources Information Center

Cruce, Ty M.; Wolniak, Gregory C.; Seifert, Tricia A.; Pascarella, Ernest T.

2006-01-01

This study estimated separately the unique effects of three dimensions of good practice and the global effects of a composite measure of good practices on the cognitive development, orientations to learning, and educational aspirations of students during their first year of college. Analyses of longitudinal data from a representative sample of…

Analysis of anthocyanins in commercial fruit juices by using nano-liquid chromatography-electrospray-mass spectrometry and high-performance liquid chromatography with UV-vis detector.

PubMed

Fanali, Chiara; Dugo, Laura; D'Orazio, Giovanni; Lirangi, Melania; Dachà, Marina; Dugo, Paola; Mondello, Luigi

2011-01-01

Nano-LC and conventional HPLC techniques were applied for the analysis of anthocyanins present in commercial fruit juices using a capillary column of 100 μm id and a 2.1 mm id narrow-bore C(18) column. Analytes were detected by UV-Vis at 518 nm and ESI-ion trap MS with HPLC and nano-LC, respectively. Commercial blueberry juice (14 anthocyanins detected) was used to optimize chromatographic separation of analytes and other analysis parameters. Qualitative identification of anthocyanins was performed by comparing the recorded mass spectral data with those of published papers. The use of the same mobile phase composition in both techniques revealed that the miniaturized method exhibited shorter analysis time and higher sensitivity than narrow-bore chromatography. Good intra-day and day-to-day precision of retention time was obtained in both methods with values of RSD less than 3.4 and 0.8% for nano-LC and HPLC, respectively. Quantitative analysis was performed by external standard curve calibration of cyanidin-3-O-glucoside standard. Calibration curves were linear in the concentration ranges studied, 0.1-50 and 6-50 μg/mL for HPLC-UV/Vis and nano-LC-MS, respectively. LOD and LOQ values were good for both methods. In addition to commercial blueberry juice, qualitative and quantitative analysis of other juices (e.g. raspberry, sweet cherry and pomegranate) was performed. The optimized nano-LC-MS method allowed an easy and selective identification and quantification of anthocyanins in commercial fruit juices; it offered good results, shorter analysis time and reduced mobile phase volume with respect to narrow-bore HPLC. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Innovative separation and preconcentration technique of coagulating homogenous dispersive micro solid phase extraction exploiting graphene oxide nanosheets.

PubMed

Ghazaghi, Mehri; Mousavi, Hassan Zavvar; Rashidi, Ali Morad; Shirkhanloo, Hamid; Rahighi, Reza

2016-01-01

A uniquely novel, fast, and facile technique is introduced for the first time in which a scant amount of graphene oxide (GO), without modification, has been utilized in dispersive mode of solid phase extraction (SPE) for an efficient yet simple separation. The proposed method of coagulating homogenous dispersive micro solid phase extraction (CHD-µSPE) is based on coagulation of homogeneous GO solution with the aid of polyetheneimine (PEI). CHD-µSPE use full adsorption capacity of GO because in this method was used GO solution obtained from synthesis process without drying step and stacking nanosheets. In optimized condition, 30 µL GO solution (7 mg mL(-1)), obtained in synthesis process, was injected into 1.5 mL the sample solution followed by immediate injection of 53 µL PEI solution (1 mg mL(-1)). After inserting PEI, GO sheets aggregate and can be readily separated by centrifugation. PEI not only cause aggregation of GO, but also form three-dimensional network of GO with easy handling in following separation steps. Lead, cadmium, and chromium were selected as model analytes and the effecting parameters including the amount of GO, concentration of PEI, sample pH, extraction time, and type of desorption solvent were investigated and optimized. The results indicate that the proposed CHD-µSPE method can be successfully applied GO in dispersive mode of SPE without effecting on good capability adsorption of GO. The novel method was applied in determination of lead, cadmium, and chromium in water, human saliva, and urine samples by electrothermal atomic absorption spectrometry. The detection limits are as low as 0.035, 0.005, and 0.012 µg L(-1) for Pb, Cd, and Cr respectively. The intra-day precisions (RSDs) were lower than 3.8%. CHD-µSPE method showed a good linear ranges of 0.24-15.6, 0.015-0.95 and 0.039-2.33 µg L(-1) for Pb, Cd and Cr respectively. Method performance was investigated by determination of mentioned metal ions in river water, human urine and saliva sample with good recoveries in range of 94.2-103.0%. The accuracy of the method was underpinned by correct analysis of a standard reference material (SRM: 2668 level I, Urine). Copyright © 2015 Elsevier B.V. All rights reserved.

A wavenumber approach to analysing the active control of plane waves with arrays of secondary sources

NASA Astrophysics Data System (ADS)

Elliott, Stephen J.; Cheer, Jordan; Bhan, Lam; Shi, Chuang; Gan, Woon-Seng

2018-04-01

The active control of an incident sound field with an array of secondary sources is a fundamental problem in active control. In this paper the optimal performance of an infinite array of secondary sources in controlling a plane incident sound wave is first considered in free space. An analytic solution for normal incidence plane waves is presented, indicating a clear cut-off frequency for good performance, when the separation distance between the uniformly-spaced sources is equal to a wavelength. The extent of the near field pressure close to the source array is also quantified, since this determines the positions of the error microphones in a practical arrangement. The theory is also extended to oblique incident waves. This result is then compared with numerical simulations of controlling the sound power radiated through an open aperture in a rigid wall, subject to an incident plane wave, using an array of secondary sources in the aperture. In this case the diffraction through the aperture becomes important when its size is compatible with the acoustic wavelength, in which case only a few sources are necessary for good control. When the size of the aperture is large compared to the wavelength, and diffraction is less important but more secondary sources need to be used for good control, the results then become similar to those for the free field problem with an infinite source array.

The “Dry-Run” Analysis: A Method for Evaluating Risk Scores for Confounding Control

PubMed Central

Wyss, Richard; Hansen, Ben B.; Ellis, Alan R.; Gagne, Joshua J.; Desai, Rishi J.; Glynn, Robert J.; Stürmer, Til

2017-01-01

Abstract A propensity score (PS) model's ability to control confounding can be assessed by evaluating covariate balance across exposure groups after PS adjustment. The optimal strategy for evaluating a disease risk score (DRS) model's ability to control confounding is less clear. DRS models cannot be evaluated through balance checks within the full population, and they are usually assessed through prediction diagnostics and goodness-of-fit tests. A proposed alternative is the “dry-run” analysis, which divides the unexposed population into “pseudo-exposed” and “pseudo-unexposed” groups so that differences on observed covariates resemble differences between the actual exposed and unexposed populations. With no exposure effect separating the pseudo-exposed and pseudo-unexposed groups, a DRS model is evaluated by its ability to retrieve an unconfounded null estimate after adjustment in this pseudo-population. We used simulations and an empirical example to compare traditional DRS performance metrics with the dry-run validation. In simulations, the dry run often improved assessment of confounding control, compared with the C statistic and goodness-of-fit tests. In the empirical example, PS and DRS matching gave similar results and showed good performance in terms of covariate balance (PS matching) and controlling confounding in the dry-run analysis (DRS matching). The dry-run analysis may prove useful in evaluating confounding control through DRS models. PMID:28338910

Biomimetic Multilayer Nanofibrous Membranes with Elaborated Superwettability for Effective Purification of Emulsified Oily Wastewater.

PubMed

Ge, Jianlong; Jin, Qing; Zong, Dingding; Yu, Jianyong; Ding, Bin

2018-05-09

Creating a porous membrane to effectively separate the emulsified oil-in-water emulsions with energy-saving property is highly desired but remains a challenge. Herein, a multilayer nanofibrous membrane was developed with the inspiration of the natural architectures of earth for gravity-driven water purification. As a result, the obtained biomimetic multilayer nanofibrous membranes exhibited three individual layers with designed functions; they were the inorganic nanofibrous layer to block the serious intrusion of oil to prevent the destructive fouling of the polymeric matrix; the submicron porous layer with designed honeycomb-like cavities to catch the smaller oil droplets and ensures a satisfactory water permeability; and the high porous fibrous substrate with larger pore size provided a template support and allows water to pass through quickly. Consequently, with the cooperation of these three functional layers, the resultant composite membrane possessed superior anti-oil-fouling property and robust oil-in-water emulsion separation performance with good separation efficiency and competitive permeation flux solely under the drive of gravity. The permeation flux of the membrane for the emulsion was up to 5163 L m -2 h -1 with a separation efficiency of 99.5%. We anticipate that our strategy could provide a facile route for developing a new generation of specific membranes for oily wastewater remediation.

Optimization of a new mobile phase to know the complex and real polyphenolic composition: towards a total phenolic index using high-performance liquid chromatography.

PubMed

Tsao, Rong; Yang, Raymond

2003-11-07

An HPLC method is reported for the separation and quantification of five major polyphenolic groups found in fruits and related products: single ring phenolic acids (hydroxybenzoic acid and hydroxycinnamic acid derivatives), flavan-3-ols, flavonols, anthocyanins, and dihydrochalcones. A binary mobile phase consisting of 6% acetic acid in 2 mM sodium acetate aqueous solution (v/v, final pH 2.55) (solvent A) and acetonitrile (solvent B) was used. The use of sodium acetate was new and key to the near baseline separation of 25 phenolics commonly found in fruits. A photodiode array detector was used and data were collected at four wavelengths (280, 320, 360, and 520 nm). This method was sensitive and gave good separation of polyphenolics in apple, cherry, strawberry, blackberry, grape, apple juice, and a processing by-product. The improved separation has led to better understanding of the polyphenolic profiles of these fruits. Individual as well as total phenolic content was obtained, and the latter was close to and correlated well with that obtained by the Folin-Ciocalteu method (FC). The HPLC data can be used as a total phenolic index (TPI) for quantification of fruit phenolics, which is advantageous over the FC because it has more information on individual compounds.

Separation of In-Vitro-Derived Megakaryocytes and Platelets Using Spinning-Membrane Filtration

PubMed Central

Schlinker, Alaina C.; Radwanski, Katherine; Wegener, Christopher; Min, Kyungyoon; Miller, William M.

2015-01-01

In-vitro-derived platelets (PLTs) could potentially overcome problems associated with donated PLTs, including contamination and alloimmunization. Although several groups have produced functional PLTs from stem cells in vitro, the challenge of developing this technology to yield transfusable PLT units has yet to be addressed. The asynchronous nature of in vitro PLT generation makes a single harvest point infeasible for collecting PLTs as soon as they are formed. The current standard of performing manual centrifugations to separate PLTs from nucleated cells at multiple points during culture is labor-intensive, imprecise, and difficult to standardize in accordance with current Good Manufacturing Practices (cGMP). In an effort to develop a more effective method, we adapted a commercially-available, spinning-membrane filtration device to separate in-vitro-derived PLTs from nucleated cells and recover immature megakaryocytes (MKs), the precursor cells to PLTs, for continued culture. Processing a mixture of in-vitro-derived MKs and PLTs on the adapted device yielded a pure PLT population and did not induce PLT pre-activation. MKs recovered from the separation process were unaffected with respect to viability and ploidy, and were able to generate PLTs after reseeding in culture. Being able to efficiently harvest in-vitro-derived PLTs brings this technology one step closer to clinical relevance. PMID:25312394

Ion-pairing reversed-phase chromatography coupled to inductively coupled plasma mass spectrometry as a tool to determine mercurial species in freshwater fish.

PubMed

Cheng, Heyong; Chen, Xiaopan; Shen, Lihuan; Wang, Yuanchao; Xu, Zigang; Liu, Jinhua

2018-01-05

Most of analytical community is focused on reversed phase high performance liquid chromatography (RP-HPLC) for mercury speciation by employing mobile phases comprising of high salts and moderate amounts of organic solvents. This study aims at rapid mercury speciation analysis by ion-pairing RP-HPLC with inductively coupled plasma mass spectrometry (ICP-MS) detection only using low salts for the sake of green analytical chemistry. Two ion-pairing HPLC methods were developed on individual usage of positively and negatively charged ion-pairing reagents (tetrabutylammonium hydroxide -TBAH and sodium dodecylbenzene sulfonate -SDBS), where sodium 3-mercapto-1-propysulfonate (MPS) and l-cysteine (Cys) were individually added in mobile phases to transform mercury species into negative and positive Hg-complexes for good resolution. Addition of phenylalanine was also utilized for rapid baseline separation in combination of short C 18 guard columns. Optimum mobile phases of 2.0mM SDBS+2.0mM Cys+1.0mM Phe (pH 3.0) and 4.0mM TBAH+2.0mM MPS+2.0mM Phe (pH 6.0) both achieved baseline separation of inorganic mercury (Hg 2+ ), methylmercury (MeHg), ethylmercury (EtHg) and phenylmercury (PhHg) on two consecutive 12.5-mm C 18 columns. The former mobile phase was selected for mercury speciation in freshwater fish because of short separation time (3.0min). Detection limits of 0.015 for Hg 2+ , 0.014 for MeHg, 0.028 for EtHg and 0.042μgL -1 for PhHg were obtained along with satisfactory precisions of peak height and area (1.0-2.8% for 5.0μgL -1 Hg-mixture standard). Good accordance of determined values of MeHg and total mercury in certified reference materials of fish tissue (GBW 10029) and tuna fish (BCR-463) with certified values as well as good recoveries (91-106%) proved good accuracy of the proposed method. An example application to freshwater fish indicated its potential in routine analysis, where MeHg was presented at 3.7-20.3μgkg -1 as the dominate species. Copyright © 2017 Elsevier B.V. All rights reserved.

Separation and screening of short-chain chlorinated paraffins in environmental samples using comprehensive two-dimensional gas chromatography with micro electron capture detection.

PubMed

Xia, Dan; Gao, Lirong; Zhu, Shuai; Zheng, Minghui

2014-11-01

Short-chain chlorinated paraffins (SCCPs) are highly complex technical mixtures with thousands of isomers and numerous homologs. They are classified as priority candidate persistent organic pollutants under the Stockholm Convention for their persistence, bioaccumulation, and toxicity. Analyzing SCCPs is challenging because of the complexity of the mixtures. Chromatograms of SCCPs acquired using one-dimensional (1D) gas chromatography (GC) contain a large characteristic "peak" with a broad and unresolved profile. Comprehensive two-dimensional GC (GC×GC) shows excellent potential for separating complex mixtures. In this study, GC×GC coupled with micro electron capture detection (μECD) was used to separate and screen SCCPs. The chromatographic parameters, including the GC column types, oven temperature program, and modulation period, were systematically optimized. The SCCP congeners were separated into groups using a DM-1 column connected to a BPX-50 column. The SCCP congeners in technical mixtures were separated according to the number of chlorine substituents for a given carbon chain length and according to the number of carbon atoms plus chlorine atoms for different carbon chain lengths. A fish tissue sample was analyzed to illustrate the feasibility of the GC×GC-μECD method in analyzing biological samples. Over 1,500 compounds were identified in the fish extract, significantly more than were identified using 1D GC. The detection limits for five selected SCCP congeners were between 1 and 5 pg/L using the GC×GC method, and these were significantly lower than those achieved using 1D GC. This method is a good choice for analysis of SCCPs in environmental samples, exhibiting good separation and good sensitivity.

Microelectrophoresis of selected mineral particles

NASA Technical Reports Server (NTRS)

Herren, B. J.; Tipps, R. W.; Alexander, K. D.

1982-01-01

Particle mobilities of ilmenite, labradorite plagioclase, enstatite pyroxene, and olivine were measured with a Rank microelectrophoresis system to evaluate indicated mineral separability. Sodium bicarbonate buffer suspension media with and without additives (0.0001 M DTAB and 5 percent v/v ethylene glycol) were used to determine differential adsorption by mineral particles and modification of relative mobilities. Good separability between some minerals was indicated; additives did not enhance separability.

Economic Assessment and Budgetary Impact of a Telemedicine Procedure and Spirometry Quality Control in the Primary Care Setting.

PubMed

Marina, Nuria; Bayón, Juan Carlos; López de Santa María, Elena; Gutiérrez, Asunción; Inchausti, Marta; Bustamante, Victor; Gáldiz, Juan B

2016-01-01

To evaluate the economic impact of a telemedicine procedure designed to improve the quality of lung function testing (LFT) in primary care in a public healthcare system, compared with the standard method. The economic impact of 9,039 LFTs performed in 51 health centers (2010-2013) using telespirometry (TS) compared to standard spirometry (SS) was studied. TS costs more per unit than SS (€47.80 vs. €39.70) (2013), but the quality of the TS procedure is superior (84% good quality, compared to 61% using the standard procedure). Total cost of TS was €431,974 (compared with €358,306€ for SS), generating an economic impact of €73,668 (2013). The increase in cost for good quality LFT performed using TS was €34,030 (2010) and €144,295 (2013), while the costs of poor quality tests fell by €15,525 (2010) and 70,627€ (2013). The cost-effectiveness analysis concludes that TS is 23% more expensive and 46% more effective. Healthcare costs consequently fall as the number of LFTs performed by TS rises. Avoiding poor quality, invalid LFTs generates savings that compensate for the increased costs of performing LFTs with TS, making it a cost-effective method. Copyright © 2014 SEPAR. Published by Elsevier Espana. All rights reserved.

An instrument for assessment of videotapes of general practitioners' performance.

PubMed Central

Cox, J; Mulholland, H

1993-01-01

OBJECTIVES--To identify those important characteristics of doctors' and patients' behaviour that distinguish between "good" and "bad" consultations when viewed on videotape; to use these characteristics to develop a reliable instrument for assessing general practitioners' performance in their own consultations. DESIGN--Questionnaires completed by patients, general practitioner trainers, and general practitioner trainees. Reliability of draft instrument tested by general practitioner trainers. SETTING--All vocational training schemes for general practice in the Northern region of England. SUBJECTS--First stage: 76 patients in seven groups, 108 general practice trainers in 12 groups, and 122 general practice trainees in 10 groups. Second stage: 85 general practice trainers in 12 groups. MAIN OUTCOME MEASURES--Trainers' ratings of importance; alpha coefficients of draft instrument by trainee, group, and consultation. RESULTS--6890 characteristics of good and bad consultations were consolidated into a draft assessment instrument consisting of 46 pairs of definitions separated by six point bipolar scales. Nine statement pairs given low importance ratings by trainers were eliminated, reducing the instrument to 37 statement pairs. To test reliability, general practitioner trainers used the instrument to assess three consultations. With the exception of one group of trainers, all alpha coefficients exceeded the acceptable level of 0.80. CONCLUSION--The instrument produced is reliable for assessing general practitioners' performance in their own consultations. PMID:8490501

Magnetically separable nanoferrite-anchored glutathione: Aqueous homocoupling of arylboronic acids under microwave irradiation

EPA Science Inventory

A highly active, stable and magnetically separable glutathione based organocatalyst provided good to excellent yields to symmetric biaryls in the homocoupling of arylboronic acids under microwave irradiation. Symmetrical biaryl motifs are present in a wide range of natural p...

CDGPS-Based Relative Navigation for Multiple Spacecraft

NASA Technical Reports Server (NTRS)

Mitchell, Megan Leigh

2004-01-01

This thesis investigates the use of Carrier-phase Differential GPS (CDGPS) in relative navigation filters for formation flying spacecraft. This work analyzes the relationship between the Extended Kalman Filter (EKF) design parameters and the resulting estimation accuracies, and in particular, the effect of the process and measurement noises on the semimajor axis error. This analysis clearly demonstrates that CDGPS-based relative navigation Kalman filters yield good estimation performance without satisfying the strong correlation property that previous work had associated with "good" navigation filters. Several examples are presented to show that the Kalman filter can be forced to create solutions with stronger correlations, but these always result in larger semimajor axis errors. These linear and nonlinear simulations also demonstrated the crucial role of the process noise in determining the semimajor axis knowledge. More sophisticated nonlinear models were included to reduce the propagation error in the estimator, but for long time steps and large separations, the EKF, which only uses a linearized covariance propagation, yielded very poor performance. In contrast, the CDGPS-based Unscented Kalman relative navigation Filter (UKF) handled the dynamic and measurement nonlinearities much better and yielded far superior performance than the EKF. The UKF produced good estimates for scenarios with long baselines and time steps for which the EKF would diverge rapidly. A hardware-in-the-loop testbed that is compatible with the Spirent Simulator at NASA GSFC was developed to provide a very flexible and robust capability for demonstrating CDGPS technologies in closed-loop. This extended previous work to implement the decentralized relative navigation algorithms in real time.

40 CFR 1065.125 - Engine intake air.

Code of Federal Regulations, 2010 CFR

2010-07-01

... engines with multiple intakes with separate humidity measurements at each intake, use a flow-weighted average humidity for NOX corrections. If individual flows of each intake are not measured, use good engineering judgment to estimate a flow-weighted average humidity. (3) Temperature. Good engineering judgment...

Impinging jet separators for liquid metal magnetohydrodynamic power cycles

NASA Technical Reports Server (NTRS)

Bogdanoff, D. W.

1973-01-01

In many liquid metal MHD power, cycles, it is necessary to separate the phases of a high-speed liquid-gas flow. The usual method is to impinge the jet at a glancing angle against a solid surface. These surface separators achieve good separation of the two phases at a cost of a large velocity loss due to friction at the separator surface. This report deals with attempts to greatly reduce the friction loss by impinging two jets against each other. In the crude impinging jet separators tested to date, friction losses were greatly reduced, but the separation of the two phases was found to be much poorer than that achievable with surface separators. Analyses are presented which show many lines of attack (mainly changes in separator geometry) which should yield much better separation for impinging jet separators).

Fabrication of zeolitic imidazolate framework-8-methacrylate monolith composite capillary columns for fast gas chromatographic separation of small molecules.

PubMed

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

2015-08-07

A composite zeolitic imidazolate framework-8 (ZIF-8) with a butyl methacrylate-co-ethylene dimethacrylate (BuMA-co-EDMA) monolithic capillary column (33.5cm long×250μm i.d.) was fabricated to enhance the separation efficiency of methacrylate monoliths toward small molecules using conventional low-pressure gas chromatography in comparison with a neat butyl methacrylate-co-ethylene dimethacrylate (BuMA-co-EDMA) monolithic capillary column (33.5cm long×250μm i.d.). The addition of 10mgmL(-1) ZIF-8 micro-particles increased the BET surface area of BuMA-co-EDMA by 3.4-fold. A fast separation of five linear alkanes in 36s with high resolution (Rs≥1.3) was performed using temperature program. Isothermal separation of the same sample also showed a high efficiency (3315platesm(-1) for octane) at 0.89min. Moreover, the column was able to separate skeletal isomers, such as iso-octane/octane and 2-methyl octane/nonane. In addition, an iso-butane/iso-butylene gas mixture was separated at ambient temperature. Comparison with an open tubular TR-5MS column (30m long×250μm i.d.) revealed the superiority of the composite column in separating the five-membered linear alkane mixture with 4-5 times increase in efficiency and a total separation time of 0.89min instead of 4.67min. A paint thinner sample was fully separated using the composite column in 2.43min with a good resolution (Rs≥0.89). The perfect combination between the polymeric monolith, with its high permeability, and ZIF-8, with its high surface area and flexible 0.34nm pore openings, led to the fast separation of small molecules with high efficiency and opened a new horizon in GC applications. Copyright © 2015 Elsevier B.V. All rights reserved.

In-tube extraction and GC-MS analysis of volatile components from wild and cultivated sea buckthorn (Hippophae rhamnoides L. ssp. Carpatica) berry varieties and juice.

PubMed

Socaci, Sonia A; Socaciu, Carmen; Tofană, Maria; Raţi, Ioan V; Pintea, Adela

2013-01-01

The health benefits of sea buckthorn (Hippophae rhamnoides L.) are well documented due to its rich content in bioactive phytochemicals (pigments, phenolics and vitamins) as well as volatiles responsible for specific flavours and bacteriostatic action. The volatile compounds are good biomarkers of berry freshness, quality and authenticity. To develop a fast and efficient GC-MS method including a minimal sample preparation technique (in-tube extraction, ITEX) for the discrimination of sea buckthorn varieties based on their chromatographic volatile fingerprint. Twelve sea buckthorn varieties (wild and cultivated) were collected from forestry departments and experimental fields, respectively. The extraction of volatile compounds was performed using the ITEX technique whereas separation and identification was performed using a GC-MS QP-2010. Principal component analysis (PCA) was applied to discriminate the differences among sample composition. Using GC-MS analysis, from the headspace of sea buckthorn samples, 46 volatile compounds were separated with 43 being identified. The most abundant derivatives were ethyl esters of 2-methylbutanoic acid, 3-methylbutanoic acid, hexanoic acid, octanoic acid and butanoic acid, as well as 3-methylbutyl 3-methylbutanoate, 3-methylbutyl 2-methylbutanoate and benzoic acid ethyl ester (over 80% of all volatile compounds). Principal component analysis showed that the first two components explain 79% of data variance, demonstrating a good discrimination between samples. A reliable, fast and eco-friendly ITEX/GC-MS method was applied to fingerprint the volatile profile and to discriminate between wild and cultivated sea buckthorn berries originating from the Carpathians, with relevance to food science and technology. Copyright © 2013 John Wiley & Sons, Ltd.

Iron oxide nanoparticle layer templated by polydopamine spheres: a novel scaffold toward hollow-mesoporous magnetic nanoreactors

NASA Astrophysics Data System (ADS)

Huang, Liang; Ao, Lijiao; Xie, Xiaobin; Gao, Guanhui; Foda, Mohamed F.; Su, Wu

2014-12-01

Superparamagnetic iron oxide nanoparticle layers with high packing density and controlled thickness were in situ deposited on metal-affinity organic templates (polydopamine spheres), via one-pot thermal decomposition. The as synthesized hybrid structure served as a facile nano-scaffold toward hollow-mesoporous magnetic carriers, through surfactant-assisted silica encapsulation and its subsequent calcination. Confined but accessible gold nanoparticles were successfully incorporated into these carriers to form a recyclable catalyst, showing quick magnetic response and a large surface area (642.5 m2 g-1). Current nano-reactors exhibit excellent catalytic performance and high stability in reduction of 4-nitrophenol, together with convenient magnetic separability and good reusability. The integration of compact iron oxide nanoparticle layers with programmable polydopamine templates paves the way to fabricate magnetic-response hollow structures, with high permeability and multi-functionality.Superparamagnetic iron oxide nanoparticle layers with high packing density and controlled thickness were in situ deposited on metal-affinity organic templates (polydopamine spheres), via one-pot thermal decomposition. The as synthesized hybrid structure served as a facile nano-scaffold toward hollow-mesoporous magnetic carriers, through surfactant-assisted silica encapsulation and its subsequent calcination. Confined but accessible gold nanoparticles were successfully incorporated into these carriers to form a recyclable catalyst, showing quick magnetic response and a large surface area (642.5 m2 g-1). Current nano-reactors exhibit excellent catalytic performance and high stability in reduction of 4-nitrophenol, together with convenient magnetic separability and good reusability. The integration of compact iron oxide nanoparticle layers with programmable polydopamine templates paves the way to fabricate magnetic-response hollow structures, with high permeability and multi-functionality. Electronic supplementary information (ESI) available: Fig. S1-S5. See DOI: 10.1039/c4nr05931j

Rapid simultaneous determination of marmelosin, umbelliferone and scopoletin from Aegle marmelos fruit by RP-HPLC.

PubMed

Shinde, P B; Katekhaye, S D; Mulik, M B; Laddha, K S

2014-09-01

The surge of interest in naturally occurring phytochemicals with high therapeutic potential has led to the discovery of many molecules, out of which naturally occuring coumarins such as marmelosin, umbelliferone and scopoletin present in Aegle marmelos (Bael) fruit shows good therapeutic potential. The aim of the present work is to develop and validate Reverse Phase-High Performance Liquid Chromatography (RP-HPLC) method for simultaneous determination of marmelosin, umbelliferone and scopoletin in A. marmelos fruit extracts. The chromatographic separation was performed with isocratic elution of 55:45 (%, v/v) methanol-water containing 0.1 % acetic acid as mobile phase. The method used to analyse the extract of A. marmelos showed good resolution with retention time within 12 min. The relative concentrations of above phytoconstituent were determined in A. marmelos fruits. The method was found to give compact peaks for scopoletin, umbelliferone and marmelosin (Rt of 4.6, 6.5 and 11.3 min respectively) and were linear over the range 5-30 μg ml(-1) (R(2) = 0.9655), 2-10 μg ml(-1) (R(2) = 0.9964) and 2-10 μg ml(-1) (R(2) = 0.9862) respectively. The mean recoveries for marmelosin, umbelliferone and scopoletin at three concentrations were in the range of 98.8-102.9, 98.8-101.1 and 94.2-98.3 % respectively. The relative standard deviation of accuracy, precision and repeatability were within 2 %, indicating the method produced highly reproducible results. Therefore this simple, precise and accurate method enables simultaneous separation of this phytoconstituent and hence can be successfully applied in analysis and routine quality control of herbal material and formulation containing A. marmelos.

Determination of nifedipine in serum of women in preterm labor by high-performance liquid chromatography with diode array detection.

PubMed

Kowalczuk, Dorota; Wawrzycka, Maria Bozena; Haratym Maj, Agnieszka

2006-01-01

Nifedipine (Nif) is widely used in treating cardiovascular disorders (especially hypertension) and for inhibiting preterm labor. A fully validated selective high-performance liquid chromatographic method with diode array detection, using solid-phase extraction, was developed for the determination of Nif in human serum. To assess specificity, Nif and its degradation products were separated on a Purospher RP-18 (5 microm, 125 x 4 mm) column plus a LiChrospher 100 RP-18 (5 microm, 4 x 4 mm) precolumn with a mobile phase of methanol-10 mM aqueous trifluoroacetic acid, pH 7.3 (57 + 43, v/v); chromatographic separation was followed by UV detection at 238 nm. For toxicological analysis, Nif in the presence of other calcium-channel antagonist drugs was identified under optimum chromatographic conditions. The calibration graph was constructed over the concentration range of 12.5-400 ng/mL in serum with good correlation (r = 0.9956). This method was not subject to interference by other plasma components and was successfully applied to the assay of Nif in spiked human serum and in serum of women in preterm labor after sublingual administration of 30 mg Nif per day divided into 3 equal doses. The mean recovery based on the ratio of the slopes of serum and mobile phase standard curves was 96.5%. The detection and quantification limits of the drug in spiked human serum were found to be 6 and 17.5 ng/mL, respectively. Validation of the method demonstrated good intraday and interday precision, which ranged from 2.18 to 6.67% and from 6.52 to 11.93%, respectively.

Three-Point Flexural Properties of Bonded Reinforcement Elements for Pleasure Craft Decks

NASA Astrophysics Data System (ADS)

Di Bella, G.; Galtieri, G.; Borsellino, C.

2018-02-01

The aim of this work was both to study the performances of pleasure craft reinforced components, bonded using a structural adhesive, and to compare them with those obtained using over-lamination as joining system, typically employed in the shipbuilding. With such aim, two different lots of components were prepared: in the first lot, the reinforcement structures were laminated directly on the investigated composite components and, in the second one; they were made separately in a mould and, then, bonded to the composite components. This last method allowed to evaluate the introduction of a product/process innovation in a field typically unwilling to innovation, still tied to craft, and non-standardized procedures. The results of bending tests, performed in order to evaluate the mechanical behaviour of the reinforced components, evidenced the goodness of this innovative design choice. Finally, a finite element analysis was performed. [Figure not available: see fulltext.

Detection of argan oil adulteration with vegetable oils by high-performance liquid chromatography-evaporative light scattering detection.

PubMed

Salghi, Rachid; Armbruster, Wolfgang; Schwack, Wolfgang

2014-06-15

Triacylglycerol profiles were selected as indicator of adulteration of argan oils to carry out a rapid screening of samples for the evaluation of authenticity. Triacylglycerols were separated by high-performance liquid chromatography-evaporative light scattering detection. Different peak area ratios were defined to sensitively detect adulteration of argan oil with vegetable oils such as sunflower, soy bean, and olive oil up to the level of 5%. Based on four reference argan oils, mean limits of detection and quantitation were calculated to approximately 0.4% and 1.3%, respectively. Additionally, 19 more argan oil reference samples were analysed by high-performance liquid chromatography-refractive index detection, resulting in highly comparative results. The overall strategy demonstrated a good applicability in practise, and hence a high potential to be transferred to routine laboratories. Copyright © 2013 Elsevier Ltd. All rights reserved.

Status and performance of the ALICE MRPC-based Time-Of-Flight detector

NASA Astrophysics Data System (ADS)

Alici, A.

2012-10-01

ALICE is the dedicated heavy-ion experiment at the CERN LHC. One of the main detectors devoted to charged hadron identification in the ALICE central barrel is a large Time-Of-Flight (TOF) array; it allows separation among pions, kaons and protons up to a few GeV/c, covering the full azimuthal angle and -0.9 < η < 0.9. The very good performance required for such a system has been achieved by means of the Multigap Resistive Plate Chamber (MRPC) whose intrinsic time resolution is better than 50 ps with an overall efficiency close to 100% and a large operational plateau; the full array consists of 1593 MRPCs covering a cylindrical surface of 141 m2. In this report, the status of the TOF detector and the performance achieved during the 2010 and 2011 data taking periods are reported together with selected physics results obtained with pp and Pb-Pb collisions.

Renewable and superior thermal-resistant cellulose-based composite nonwoven as lithium-ion battery separator.

PubMed

Zhang, Jianjun; Liu, Zhihong; Kong, Qingshan; Zhang, Chuanjian; Pang, Shuping; Yue, Liping; Wang, Xuejiang; Yao, Jianhua; Cui, Guanglei

2013-01-01

A renewable and superior thermal-resistant cellulose-based composite nonwoven was explored as lithium-ion battery separator via an electrospinning technique followed by a dip-coating process. It was demonstrated that such nanofibrous composite nonwoven possessed good electrolyte wettability, excellent heat tolerance, and high ionic conductivity. The cells using the composite separator displayed better rate capability and enhanced capacity retention, when compared to those of commercialized polypropylene separator under the same conditions. These fascinating characteristics would endow this renewable composite nonwoven a promising separator for high-power lithium-ion battery.

Impact on knowledge and behaviour of the general population of two different methods of solid waste management: An explorative cross-sectional study.

PubMed

Del Cimmuto, Angela; Mannocci, Alice; Ribatti, Domenico; Boccia, Antonio; La Torre, Giuseppe

2014-06-01

The objectives of the present study were to evaluate knowledge among general population about the risks factors of waste management, to estimate the feeling of anxiety concerning the waste, and to compare knowledge of two different methods for collecting municipal solid waste (MSW): a street separate collection system and a door-to-door separate collection system. A cross-sectional study was performed, administering an anonymous questionnaire to 180 inhabitants in Aprilia, Latium, Italy. The study sample consisted of 183 citizens: 64 in the intervention group and 119 in the control group. The intervention was represented by a campaign of door-to-door collection. The correct implementation of separate collection of waste was 87.5% in the intervention group and 63% in the control group (p<0.001). For both groups, the favourite type of waste collection was door-to-door (p=0.013); a high difference concerning the quality of information was found (p<0.0001): in the intervention group, 84% declared to be satisfied (67% sufficient and 17.2% good), while in the control group, 21% declared to be satisfied (16.8% sufficient and 4.2% good). The advice mainly reported from the control group respondents was to increase the size of the information pack (80.7%, p=0.024). The information campaign seemed to increase people's awareness about the problem, improving the management of waste and household waste. The door-to-door collection was appreciated and preferred by both groups. The adoption of a door-to-door scheme seems to be a winning option mostly because it is supported by an information and education system for the citizens. © The Author(s) 2014.

Structure of Enhanced Cued Recall Task in the 7 Minute Screen Test.

PubMed

Mora-Simon, Sara; Ladera-Fernandez, Valentina; Garcia-Garcia, Ricardo; Patino-Alonso, María C; Perea-Bartolome, M Victoria; Unzueta-Arce, Jaime; Perez-Arechaederra, Diana; Rodriguez-Sanchez, Emiliano

2017-01-01

Episodic memory in the 7 Minute Screen is assessed by the Enhanced Cued Recall (ECR) test. The ECR test is composed of three phases, Identification, Immediate Recall, and Free and Cued Recall. However, just the last phase is considered for the total score. We believe that collecting the performance data of the Identification and Immediate Recall phases could provide information regarding possible difficulties or impairments in the different aspects involved in the temporal mnesic process of acquisition of new information, such as in working memory or visual identification. The objective was to assess the goodness of fit for the three phases of the ECR test using a Confirmatory Factor Analysis (CFA) to show if each phase is separated from each other as a different aspect that participates in the mnesic process. A total of 311 participants greater than 65 years were included in this study. Confirmatory factor analyses were conducted for each individual phase. The analyses show that the ECR test consists of three separate phases that identify different steps of the mnesic process. Individual scores for each phase could allow for investigation of patient performance in different aspects of the memory process and could help in further neuropsychological assessment.

Plasma creatinine and creatine quantification by capillary electrophoresis diode array detector.

PubMed

Zinellu, Angelo; Caria, Marcello A; Tavera, Claudio; Sotgia, Salvatore; Chessa, Roberto; Deiana, Luca; Carru, Ciriaco

2005-07-15

Traditional clinical assays for nonprotein nitrogen compounds, such as creatine and creatinine, have focused on the use of enzymes or chemical reactions that allow measurement of each analyte separately. Most of these assays are mainly directed to urine quantification, so that their applicability on plasma samples is frequently hard to perform. This work describes a simple free zone capillary electrophoresis method for the simultaneous measurement of creatinine and creatine in human plasma. The effect of analytical parameters such as concentration and pH of Tris-phosphate running buffer and cartridge temperature on resolution, migration times, peak areas, and efficiency was investigated. Good separation was achieved using a 60.2-cm x 75-microm uncoated silica capillary, 75 mmol/L Tris-phosphate buffer, pH 2.25, at 15 degrees C, in less than 8 min. We compared the present method to a validated capillary electrophoresis assay, by measuring plasma creatinine in 120 normal subjects. The obtained data were compared by the Passing-Bablok regression and the Bland-Altman test. Moreover the performance of the developed method was assessed by measuring creatine and creatinine in 16 volunteers prior to and after a moderate physical exercise.

Comprehensive determination of flavouring additives and nicotine in e-cigarette refill solutions. Part I: Liquid chromatography-tandem mass spectrometry analysis.

PubMed

Aszyk, Justyna; Kubica, Paweł; Kot-Wasik, Agata; Namieśnik, Jacek; Wasik, Andrzej

2017-10-13

Liquid chromatography-tandem mass spectrometry with electrospray ionization (HPLC-ESI-MS/MS) methods were developed for the simultaneous determination of 42 flavouring compounds and nicotine in liquids for e-cigarettes. The chromatographic separation was performed using an Ace ® Ultracore™ SuperC18™ (100×2.1mm, 2.5μm) column in both acidic and alkaline pH conditions to separate all the compounds. A simple "dilute & shoot" approach was used for the sample preparation. The method validation was performed by evaluating key analytical parameters such as linearity, accuracy, selectivity, precision, limit of detection (LOD) and limit of quantification (LOQ). The calibration curves showed good linearity within the specific ranges for the investigated compounds with correlation coefficients greater than 0.990 in each case. The recovery for all the investigated compounds varied from 89% to 110%. The intra- and inter-day precision were within the acceptable limits (±15%) at all tested concentrations. The applicability of the methods was examined by analysing 25 liquid samples from e-cigarettes commercially available on the Polish market. Copyright © 2017 Elsevier B.V. All rights reserved.

Fast Simultaneous Determination of 13 Nucleosides and Nucleobases in Cordyceps sinensis by UHPLC-ESI-MS/MS.

PubMed

Zong, Shi-Yu; Han, Han; Wang, Bing; Li, Ning; Dong, Tina Ting-Xia; Zhang, Tong; Tsim, Karl W K

2015-12-04

A reliable ultra-high-performance liquid chromatography-electrospray ionization-tandem mass spectrometry (UHPLC-ESI-MS/MS) method for the fast simultaneous determination of 13 nucleosides and nucleobases in Cordyceps sinensis (C. sinensis) with 2-chloroadenosine as internal standard was developed and validated. Samples were ultrasonically extracted in an ice bath thrice, and the optimum analyte separation was performed on an ACQUITY UPLC(TM) HSS C18 column (100 mm × 2.1 mm, 1.8 μm) with gradient elution. All targeted analytes were separated in 5.5 min. Furthermore, all calibration curves showed good linear regression (r > 0.9970) within the test ranges, and the limits of quantitation and detection of the 13 analytes were less than 150 and 75 ng/mL, respectively. The relative standard deviations (RSDs) of intra- and inter-day precisions were <6.23%. Recoveries of the quantified analytes ranged within 85.3%-117.3%, with RSD < 6.18%. The developed UHPLC-ESI-MS/MS method was successfully applied to determine nucleosides and nucleobases in 11 batches of C. sinensis samples from different regions in China. The range for the total content in the analyzed samples was 1329-2057 µg/g.

Mix Model Comparison of Low Feed-Through Implosions

NASA Astrophysics Data System (ADS)

Pino, Jesse; MacLaren, S.; Greenough, J.; Casey, D.; Dewald, E.; Dittrich, T.; Khan, S.; Ma, T.; Sacks, R.; Salmonson, J.; Smalyuk, V.; Tipton, R.; Kyrala, G.

2016-10-01

The CD Mix campaign previously demonstrated the use of nuclear diagnostics to study the mix of separated reactants in plastic capsule implosions at the NIF. Recently, the separated reactants technique has been applied to the Two Shock (TS) implosion platform, which is designed to minimize this feed-through and isolate local mix at the gas-ablator interface and produce core yields in good agreement with 1D clean simulations. The effects of both inner surface roughness and convergence ratio have been probed. The TT, DT, and DD neutron signals respectively give information about core gas performance, gas-shell atomic mix, and heating of the shell. In this talk, we describe efforts to model these implosions using high-resolution 2D ARES simulations. Various methods of interfacial mix will be considered, including the Reynolds-Averaged Navier Stokes (RANS) KL method as well as and a multicomponent enhanced diffusivity model with species, thermal, and pressure gradient terms. We also give predictions of a upcoming campaign to investigate Mid-Z mixing by adding a Ge dopant to the CD layer. LLNL-ABS-697251 This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

Simultaneous separation and determination of eleven nucleosides and bases in beer, herring sperm DNA and RNA soft capsule by high-performance liquid chromatography.

PubMed

Hou, Shengjie; Ding, Mingyu

2010-01-01

A simple and rapid high-performance liquid chromatography method was developed for the determination of eleven nucleosides and bases in beer, herring sperm DNA and RNA soft capsules. The separation was carried out on an Agilent extend-C(18) column with a simple gradient elution of acetonitrile and water as the mobile phase. Good linear relationships between the peak areas and the concentrations of the analytes were obtained. The detection limits for eleven analytes were in the range of 0.007-0.037 mg/L by UV detection at 260 nm. The relative standard deviations (RSDs) of the retention times were in the range of 0.78-1.85% for intra-day and 0.87-1.94% for inter-day, respectively. The RSDs of the peak areas were in the range of 2.71-3.22% for intra-day and 3.03-3.39% for inter-day, respectively. This method has been successfully applied to simultaneous determination of eleven nucleosides and bases in beer, herring sperm DNA and RNA soft capsules with the recoveries in the range of 93.7-108.3%.

A latent class multiple constraint multiple discrete-continuous extreme value model of time use and goods consumption.

DOT National Transportation Integrated Search

2016-06-01

This paper develops a microeconomic theory-based multiple discrete continuous choice model that considers: (a) that both goods consumption and time allocations (to work and non-work activities) enter separately as decision variables in the utility fu...

[Determination of patulin in fruits and jam by solid phase extraction-ultra performance liquid chromatography].

PubMed

Lü, Weichao; Shen, Shuchang; Wang, Chao

2017-11-08

With magnesium silicate, silica gel, diatomite and calcium sulfate as raw materials, a new solid phase extraction column was prepared through a series of processes of grinding to ethanol homogenate, drying and packing into polypropylene tube. The sample was hydrolyzed by pectinase, extracted by acetonitrile and purified by solid phase extraction. The target compounds were separated on a C18 column (100 mm×2.1 mm, 1.8 μm), using 0.8% (v/v) tetrahydrofuran solution as mobile phase with a flow rate of 0.5 mL/min. The detection wavelength was 276 nm. The effect of pectinase on extraction yield and purification effect of solid-phase extraction column were investigated. The optimum chromatographic conditions were selected. There was a good linear relationship between the peak heights and the mass concentrations of patulin in the range of 0.1 to 10 mg/L with the correlation coefficient ( R 2 ) of 1. The limit of detection for this method was 10.22 μg/kg. The spiked recoveries of samples were 86.58%-94.84% with the relative standard deviations (RSDs) of 1.45%-2.28%. The results indicated that the self-made solid phase extraction column had a good purification efficiency, and the UPLC had a high separation efficiency. The method is simple, accurate and of great significance for the quality and safety control of fruit products.

Analysis of the volatile organic matter of engine piston deposits by direct sample introduction thermal desorption gas chromatography/mass spectrometry.

PubMed

Diaby, M; Kinani, S; Genty, C; Bouchonnet, S; Sablier, M; Le Negrate, A; El Fassi, M

2009-12-01

This article establishes an alternative method for the characterization of volatiles organic matter (VOM) contained in deposits of the piston first ring grooves of diesel engines using a ChromatoProbe direct sample introduction (DSI) device coupled to gas chromatography/mass spectrometry (GC/MS) analysis. The addition of an organic solvent during thermal desorption leads to an efficient extraction and a good chromatographic separation of extracted products. The method was optimized investigating the effects of several solvents, the volume added to the solid sample, and temperature programming of the ChromatoProbe DSI device. The best results for thermal desorption were found using toluene as an extraction solvent and heating the programmable temperature injector from room temperature to 300 degrees C with a temperature step of 105 degrees C. With the use of the optimized thermal desorption conditions, several components have been positively identified in the volatile fraction of the deposits: aromatics, antioxidants, and antioxidant degradation products. Moreover, this work highlighted the presence of diesel fuel in the VOM of the piston deposits and gave new facts on the absence of the role of diesel fuel in the deposit formation process. Most importantly, it opens the possibility of quickly performing the analysis of deposits with small amounts of samples while having a good separation of the volatiles.

Green synthesis of a typical chiral stationary phase of cellulose-tris(3, 5-dimethylphenylcarbamate)

PubMed Central

2013-01-01

Background At present, the study on the homogeneous-phase derivatization of cellulose in ionic liquid is mainly focused on its acetylation. To the best of our knowledge, there has been no such report on the preparation of cellulose-tris(3,5-dimethylphenylcarbamate) (CDMPC) with ionic liquid 1-allyl-3-methyl-imidazolium chloride (AmimCl) so far. Results With ionic liquid 1-allyl-3-methylimidazolium chloride (AmimCl) as a reaction solvent, cellulose-tris(3,5-dimethylphenylcarbamate) (CDMPC) was synthesized by the reaction of 3,5-dimethylphenyl isocyanate and soluble microcrystalline cellulose in a homogeneous phase. The synthesized CDMPC was then coated onto the surfaces of aminopropyl silica gel to prepare a chiral stationary phase (CSP). The prepared CSP was successfully used in chiral separation of seven racemic pesticides by high performance liquid chromatography (HPLC). Good chiral separation was obtained using n-hexane and different modifiers as the mobile phases under the optimal percentage and column temperature, with the resolution of metalaxyl, diniconazole, flutriafol, paclobutrazol, hexaconazole, myclobutanil and hexythiazox of 1.73, 1.56, 1.26, 1.00, 1.18, 1.14 and 1.51, respectively. The experimental results suggested it was a good choice using a green solvent of AmimCl for cellulose functionalization. Conclusion CDMPC was successfully synthesized as the chiral selector by reacting 3, 5-dimethylphenyl isocyanate with dissolved microcrystalline cellulose in a green ionic liquid of AmimCl. PMID:23890199

Mixed mode HILIC/anion exchange separations on latex coated silica monoliths.

PubMed

Ibrahim, Mohammed E A; Lucy, Charles A

2012-10-15

Bare silica monoliths do not possess anion exchange sites hence they show low retention for anions. Moreover, bare silica monoliths show low retention in hydrophilic interaction liquid chromatography (HILIC). Coating the silica surface with cationic nanoparticles e.g. AS9-SC (latex A), AS12A (latex B) and DNApac (latex C) increases the thickness of the water layer on the Onyx silica monolith 8-10 times enabling HILIC retention when a high % acetonitrile (ACN) mobile phase is used. The formed water layer by itself is not sufficient to perform good separation of the studied anions (acetate, formate, nitrate, bromate, thiocyanate and iodide). On the other hand, the latex nanoparticles introduce positively charged sites, making anion exchange chromatography possible, with the anion exchange capacity varying with the latex adsorbed (44.1 ± 0.2, 4.4 ± 0.1 and 14.0 ± 0.7 μeq/column for latex A, B and C, respectively). Latex A nanoparticles which provided the highest ion exchange capacity separated all tested anions with reasonable resolution. Fast separation (2.5 min) of acetate, formate, nitrate, bromate, thiocyanate and iodide was performed using the latex A coated silica monolith. The obtained efficiencies are 13,000-50,000 plates/m at 3 mL/min with a minimum resolution of 0.85. Retention is mixed mode under HILIC conditions with HILIC dominating for the kosmotropic anions and ion exchange dominating for the chaotropic anions. The two different brands of silica monoliths (Merck Chromolith and Phenomenex Onyx) coated with the same latex A nanoparticles displayed similar water layer volumes, ion exchange capacity and selectivity. Copyright © 2012 Elsevier B.V. All rights reserved.

Single-step CE for miniaturized and easy-to-use system.

PubMed

Ono, Koichi; Kaneda, Shohei; Fujii, Teruo

2013-03-01

We developed a novel single-step capillary electrophoresis (SSCE) scheme for miniaturized and easy to use system by using a microchannel chip, which was made from the hydrophilic material polymethyl methacrylate (PMMA), equipped with a capillary stop valve. Taking the surface tension property of liquids into consideration, the capillary effect was used to introduce liquids and control capillary stop valves in a partial barrier structure in the wall of the microchannel. Through the combined action of stop valves and air vents, both sample plug formation for electrophoresis and sample injection into a separation channel were successfully performed in a single step. To optimize SSCE, different stop valve structures were evaluated using actual microchannel chips and the finite element method with the level set method. A partial barrier structure at the bottom of the channel functioned efficiently as a stop valve. The stability of stop valve was confirmed by a shock test, which was performed by dropping the microchannel chip to a floor. Sample plug deformation could be reduced by minimizing the size of the side partial barrier. By dissolving hydroxyl ethyl cellulose and using it as the sample solution, the EOF and adsorption of the sample into the PMMA microchannel were successfully reduced. Using this method, a 100-bp DNA ladder was concentrated; good separation was observed within 1 min. At a separation length of 5 mm, the signal was approximately 20-fold higher than a signal of original sample solution by field-amplified sample stacking effect. All operations, including liquid introduction and sample separation, can be completed within 2 min by using the SSCE scheme. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Can suicide be a good death?

PubMed

Lester, David

2006-01-01

The issue of whether suicide can be a good death was separated into two different questions: (1) can suicide be an appropriate death, and (2) can suicide be a rational death? Several definitions of an "appropriate" death were proposed, and suicide was seen as potentially appropriate. Similarly, several criteria for rationality were proposed and suicide was seen as sometimes meeting these criteria. Thus, suicide can be sometimes conceptualized as a "good" death.

High-Performance Lithium-Sulfur Batteries with a Self-Assembled Multiwall Carbon Nanotube Interlayer and a Robust Electrode-Electrolyte Interface.

PubMed

Kim, Hee Min; Hwang, Jang-Yeon; Manthiram, Arumugam; Sun, Yang-Kook

2016-01-13

Elemental sulfur electrode has a huge advantage in terms of charge-storage capacity. However, the lack of electrical conductivity results in poor electrochemical utilization of sulfur and performance. This problem has been overcome to some extent previously by using a bare multiwall carbon nanotube (MWCNT) paper interlayer between the sulfur cathode and the polymeric separator, resulting in good electron transport and adsorption of dissolved polysulfides. To advance the interlayer concept further, we present here a self-assembled MWCNT interlayer fabricated by a facile, low-cost process. The Li-S cells fabricated with the self-assembled MWCNT interlayer and a high loading of 3 mg cm(-2) sulfur exhibit a first discharge specific capacity of 1112 mAh g(-1) at 0.1 C rate and retain 95.8% of the capacity at 0.5 C rate after 100 cycles as the self-assembled MWCNT interlayer facilitates good interfacial contact between the interlayer and the sulfur cathode and fast electron and lithium-ion transport while trapping and reutilizing the migrating polysulfides. The approach presented here has the potential to advance the commercialization feasibility of the Li-S batteries.

Removal of Hg(II) from aqueous solution by resin loaded magnetic β-cyclodextrin bead and graphene oxide sheet: Synthesis, adsorption mechanism and separation properties.

PubMed

Cui, Limei; Wang, Yaoguang; Gao, Liang; Hu, Lihua; Wei, Qin; Du, Bin

2015-10-15

Resin loaded magnetic β-cyclodextrin bead and graphene oxide sheet (MCD-GO-R) was synthesized successfully and found to be an excellent adsorbent for Hg(II) removal. The as-prepared adsorbent was characterized by SEM, FTIR, BET, magnetization curve and zeta potential analysis respectively. Good magnetic performance made MCD-GO-R simply recover from aqueous solution at low magnetic field within 30s. And also, the rich functional groups and outstanding dispersity play an important role in the adsorption process. The maximum adsorption capacity was 88.43 mg g(-1) at 323 K and pH 7.1. The as-prepared adsorbent could perform well in a wide pH range from 4.0 to 10.0. Static adsorption experimental data showed good correlation with pseudo-second-order model and Freundlich isotherm models. It was found that the contaminant adsorption was accomplished mainly via chelation or ion exchange and come to equilibrium in only 30 min. All experimental results, especially the excellent reproducibility and resistance to ion interference, suggest that MCD-GO-R has promising applications in water treatment. Copyright © 2015 Elsevier Inc. All rights reserved.

A study of Acoustics Performance on Natural Fibre Composite

NASA Astrophysics Data System (ADS)

Nizam Yahya, Musli; Sambu, Mathan; Latif, Hanif Abdul; Junaid, Thuwaibah Mohd

2017-08-01

Natural fibres are fibre that can be directly obtained from an animal, mineral, or vegetable sources. Recently natural materials are becoming good alternatives for synthetic material as they provide good health to greener environment. The purpose of this study is to investigate and compare the acoustic characteristics of natural fibres; Kenaf fibre, Ijuk fibre, coconut coir and palm Oil frond. During the processing stage, each fibre is reinforced with 60:40 weight ratio of natural rubber (NR) separately. The fibres are then compressed after the natural rubber (NR) treatment into circular samples, of 28 mm and 100 mm diameters respectively. The thickness of each sample is fixed at 50mm. The acoustical performances were evaluated by using an impedance tube instrument. The frequency peak value of Kenaf is obtained in a range of 700 Hz - 800 Hz, while for coconut coir is at 1000 Hz - 1075 Hz frequency range. Palm oil frond gives high frequency at 850 Hz - 1200 Hz. However, Only Ijuk has obtained the highest frequency range of 3200 Hz - 3400 Hz. The results demonstrate that these fibres are a promising light and environment-friendly sound absorption material as they are ready to replace the common synthetic fibre.

An application of the theory of planned behaviour to study the influencing factors of participation in source separation of food waste.

PubMed

Karim Ghani, Wan Azlina Wan Ab; Rusli, Iffah Farizan; Biak, Dayang Radiah Awang; Idris, Azni

2013-05-01

Tremendous increases in biodegradable (food waste) generation significantly impact the local authorities, who are responsible to manage, treat and dispose of this waste. The process of separation of food waste at its generation source is identified as effective means in reducing the amount food waste sent to landfill and can be reused as feedstock to downstream treatment processes namely composting or anaerobic digestion. However, these efforts will only succeed with positive attitudes and highly participations rate by the public towards the scheme. Thus, the social survey (using questionnaires) to analyse public's view and influencing factors towards participation in source separation of food waste in households based on the theory of planned behaviour technique (TPB) was performed in June and July 2011 among selected staff in Universiti Putra Malaysia, Serdang, Selangor. The survey demonstrates that the public has positive intention in participating provided the opportunities, facilities and knowledge on waste separation at source are adequately prepared by the respective local authorities. Furthermore, good moral values and situational factors such as storage convenience and collection times are also encouraged public's involvement and consequently, the participations rate. The findings from this study may provide useful indicator to the waste management authorities in Malaysia in identifying mechanisms for future development and implementation of food waste source separation activities in household programmes and communication campaign which advocate the use of these programmes. Copyright © 2012 Elsevier Ltd. All rights reserved.

21 CFR 146.151 - Orange juice for manufacturing.

Code of Federal Regulations, 2011 CFR

2011-04-01

... apply to the hybrid species described in § 146.135). Seeds (except embryonic seeds and small fragments of seeds that cannot be separated by good manufacturing practice) are removed, and pulp and orange oil may be adjusted in accordance with good manufacturing practice. If pulp is added it shall be other...

Preparation and electrochemical characterization of ionic-conducting lithium lanthanum titanate oxide/polyacrylonitrile submicron composite fiber-based lithium-ion battery separators

NASA Astrophysics Data System (ADS)

Liang, Yinzheng; Ji, Liwen; Guo, Bingkun; Lin, Zhan; Yao, Yingfang; Li, Ying; Alcoutlabi, Mataz; Qiu, Yiping; Zhang, Xiangwu

Lithium lanthanum titanate oxide (LLTO)/polyacrylonitrile (PAN) submicron composite fiber-based membranes were prepared by electrospinning dispersions of LLTO ceramic particles in PAN solutions. These ionic-conducting LLTO/PAN composite fiber-based membranes can be directly used as lithium-ion battery separators due to their unique porous structure. Ionic conductivities were evaluated after soaking the electrospun LLTO/PAN composite fiber-based membranes in a liquid electrolyte, 1 M lithium hexafluorophosphate (LiPF 6) in ethylene carbonate (EC)/ethyl methyl carbonate (EMC) (1:1 vol). It was found that, among membranes with various LLTO contents, 15 wt.% LLTO/PAN composite fiber-based membranes provided the highest ionic conductivity, 1.95 × 10 -3 S cm -1. Compared with pure PAN fiber membranes, LLTO/PAN composite fiber-based membranes had greater liquid electrolyte uptake, higher electrochemical stability window, and lower interfacial resistance with lithium. In addition, lithium//1 M LiPF 6/EC/EMC//lithium iron phosphate cells containing LLTO/PAN composite fiber-based membranes as the separator exhibited high discharge specific capacity of 162 mAh g -1 and good cycling performance at 0.2 C rate at room temperature.

Simultaneous microemulsion liquid chromatographic analysis of fat-soluble vitamins in pharmaceutical formulations: optimization using genetic algorithm.

PubMed

Momenbeik, Fariborz; Roosta, Mostafa; Nikoukar, Ali Akbar

2010-06-11

An environmentally benign and simple method has been proposed for separation and determination of fat-soluble vitamins using isocratic microemulsion liquid chromatography. Optimization of parameters affecting the separation selectivity and efficiency including surfactant concentration, percent of cosurfactant (1-butanol), and percent of organic oily solvent (diethyl ether), temperature and pH were performed simultaneously using genetic algorithm method. A new software package, MLR-GA, was developed for this purpose. The results indicated that 73.6mM sodium dodecyl sulfate, 13.64% (v/v) 1-butanol, 0.48% (v/v) diethyl ether, column temperature of 32.5 degrees C and 0.02M phosphate buffer of pH 6.99 are the best conditions for separation of fat-soluble vitamins. At the optimized conditions, the calibration plots for the vitamins were obtained and detection limits (1.06-3.69microgmL(-1)), accuracy (recoveries>94.3), precision (RSD<3.96) and linearity (0.01-10mgmL(-1)) were estimated. Finally, the amount of vitamins in multivitamin syrup and a sample of fish oil capsule were determined. The results showed a good agreement with those reported by manufactures. Copyright 2010 Elsevier B.V. All rights reserved.

Ni-MH spent batteries: a raw material to produce Ni-Co alloys.

PubMed

Lupi, Carla; Pilone, Daniela

2002-01-01

Ni-MH spent batteries are heterogeneous and complex materials, so any kind of metallurgical recovery process needs a mechanical pre-treatment at least to separate irony materials and recyclable plastic materials (like ABS) respectively, in order to get additional profit from this saleable scrap, as well as minimize waste arising from the braking separation process. Pyrometallurgical processing is not suitable to treat Ni-MH batteries mainly because of Rare Earths losses in the slag. On the other hand, the hydrometallurgical method, that offers better opportunities in terms of recovery yield and higher purity of Ni, Co, and RE, requires several process steps as shown in technical literature. The main problems during leach liquor purification are the removal of elements such as Mn, Zn, Cd, dissolved during the leaching step, and the separation of Ni from Co. In the present work, the latter problem is overcome by co-deposition of a Ni-35/40%w Co alloy of good quality. The experiments carried out in a laboratory scale pilot-plant show that a current efficiency higher than 91% can be reached in long duration electrowinning tests performed at 50 degrees C and 4.3 catholyte pH.

Microporous polystyrene particles for selective carbon dioxide capture.

PubMed

Kaliva, Maria; Armatas, Gerasimos S; Vamvakaki, Maria

2012-02-07

This study presents the synthesis of microporous polystyrene particles and the potential use of these materials in CO(2) capture for biogas purification. Highly cross-linked polystyrene particles are synthesized by the emulsion copolymerization of styrene (St) and divinylbenzene (DVB) in water. The cross-link density of the polymer is varied by altering the St/DVB molar ratio. The size and the morphology of the particles are characterized by scanning and transmission electron microscopy. Following supercritical point drying with carbon dioxide or lyophilization from benzene, the polystyrene nanoparticles exhibit a significant surface area and permanent microporosity. The dried particles comprising 35 mol % St and 65 mol % DVB possess the largest surface area, ∼205 m(2)/g measured by Brunauer-Emmett-Teller and ∼185 m(2)/g measured by the Dubinin-Radushkevich method, and a total pore volume of 1.10 cm(3)/g. Low pressure measurements suggest that the microporous polystyrene particles exhibit a good separation performance of CO(2) over CH(4), with separation factors in the range of ∼7-13 (268 K, CO(2)/CH(4) = 5/95 gas mixture), which renders them attractive candidates for use in gas separation processes.

Design of an interface to allow microfluidic electrophoresis chips to drink from the fire hose of the external environment.

PubMed

Attiya, S; Jemere, A B; Tang, T; Fitzpatrick, G; Seiler, K; Chiem, N; Harrison, D J

2001-01-01

An interface design is presented that facilitates automated sample introduction into an electrokinetic microchip, without perturbing the liquids within the microfluidic device. The design utilizes an interface flow channel with a volume flow resistance that is 0.54-4.1 x 10(6) times lower than the volume flow resistance of the electrokinetic fluid manifold used for mixing, reaction, separation, and analysis. A channel, 300 microm deep, 1 mm wide and 15-20 mm long, was etched in glass substrates to create the sample introduction channel (SIC) for a manifold of electrokinetic flow channels in the range of 10-13 microm depth and 36-275 microm width. Volume flow rates of up to 1 mL/min were pumped through the SIC without perturbing the solutions within the electrokinetic channel manifold. Calculations support this observation, suggesting a leakage flow to electroosmotic flow ratio of 0.1:1% in the electrokinetic channels, arising from 66-700 microL/min pressure-driven flow rates in the SIC. Peak heights for capillary electrophoresis separations in the electrokinetic flow manifold showed no dependence on whether the SIC pump was on or off. On-chip mixing, reaction and separation of anti-ovalbumin and ovalbumin could be performed with good quantitative results, independent of the SIC pump operation. Reproducibility of injection performance, estimated from peak height variations, ranged from 1.5-4%, depending upon the device design and the sample composition.

Multiparametric fat-water separation method for fast chemical-shift imaging guidance of thermal therapies.

PubMed

Lin, Jonathan S; Hwang, Ken-Pin; Jackson, Edward F; Hazle, John D; Stafford, R Jason; Taylor, Brian A

2013-10-01

A k-means-based classification algorithm is investigated to assess suitability for rapidly separating and classifying fat/water spectral peaks from a fast chemical shift imaging technique for magnetic resonance temperature imaging. Algorithm testing is performed in simulated mathematical phantoms and agar gel phantoms containing mixed fat/water regions. Proton resonance frequencies (PRFs), apparent spin-spin relaxation (T2*) times, and T1-weighted (T1-W) amplitude values were calculated for each voxel using a single-peak autoregressive moving average (ARMA) signal model. These parameters were then used as criteria for k-means sorting, with the results used to determine PRF ranges of each chemical species cluster for further classification. To detect the presence of secondary chemical species, spectral parameters were recalculated when needed using a two-peak ARMA signal model during the subsequent classification steps. Mathematical phantom simulations involved the modulation of signal-to-noise ratios (SNR), maximum PRF shift (MPS) values, analysis window sizes, and frequency expansion factor sizes in order to characterize the algorithm performance across a variety of conditions. In agar, images were collected on a 1.5T clinical MR scanner using acquisition parameters close to simulation, and algorithm performance was assessed by comparing classification results to manually segmented maps of the fat/water regions. Performance was characterized quantitatively using the Dice Similarity Coefficient (DSC), sensitivity, and specificity. The simulated mathematical phantom experiments demonstrated good fat/water separation depending on conditions, specifically high SNR, moderate MPS value, small analysis window size, and low but nonzero frequency expansion factor size. Physical phantom results demonstrated good identification for both water (0.997 ± 0.001, 0.999 ± 0.001, and 0.986 ± 0.001 for DSC, sensitivity, and specificity, respectively) and fat (0.763 ± 0.006, 0.980 ± 0.004, and 0.941 ± 0.002 for DSC, sensitivity, and specificity, respectively). Temperature uncertainties, based on PRF uncertainties from a 5 × 5-voxel ROI, were 0.342 and 0.351°C for pure and mixed fat/water regions, respectively. Algorithm speed was tested using 25 × 25-voxel and whole image ROIs containing both fat and water, resulting in average processing times per acquisition of 2.00 ± 0.07 s and 146 ± 1 s, respectively, using uncompiled MATLAB scripts running on a shared CPU server with eight Intel Xeon(TM) E5640 quad-core processors (2.66 GHz, 12 MB cache) and 12 GB RAM. Results from both the mathematical and physical phantom suggest the k-means-based classification algorithm could be useful for rapid, dynamic imaging in an ROI for thermal interventions. Successful separation of fat/water information would aid in reducing errors from the nontemperature sensitive fat PRF, as well as potentially facilitate using fat as an internal reference for PRF shift thermometry when appropriate. Additionally, the T1-W or R2* signals may be used for monitoring temperature in surrounding adipose tissue.

Magnetically recyclable Bi/Fe-based hierarchical nanostructures via self-assembly for environmental decontamination

NASA Astrophysics Data System (ADS)

Hu, Zhong-Ting; Chen, Zhong; Goei, Ronn; Wu, Weiyi; Lim, Teik-Thye

2016-06-01

Pristine bismuth ferrite usually possesses weak magnetic properties (e.g., saturation magnetization Ms < 3 emu g-1) for practical magnetic separation applications. Herein, a superparamagnetic bismuth ferrite with coral-like hierarchical morphology (BFO-M) was fabricated through methanol solvothermal treatment of the as-prepared Bi2Fe4O9 nanoclusters (P-BFO). The BFO-M shows a higher Ms of ~31 emu g-1 compared to that of P-BFO treated in water (BFO-A), in ethanol (BFO-E) and in ethylene glycol (BFO-G). Compared to single-crystalline Bi2Fe4O9 (PS) and Bi2Fe4O9 clusters (NSP), BFO-M shows an excellent organic pollutant removal rate by virtue of its high adsorption capacity and catalytic activity when methyl orange (MO) is used as the model organic pollutant. BFO-M also exhibits good visible light photo-Fenton oxidation rates for pharmaceuticals and pesticides. Even at a low catalyst loading of 0.12 g L-1, the removal rate of organic pollutants (e.g., 5-fluorouracil, isoproturon) can be ~99% in 100 min under visible light irradiation. Besides, BFO-M is also a good adsorbent for different kinds of heavy metal ions (Pb(ii), Cr(iii), Cu(ii), As(v), etc.). For example, its maximal adsorption capacity for Pb(ii) is 214.5 mg g-1. The used BFO-M can be recovered via magnetic separation. The outstanding performances of BFO-M can be ascribed to its coral-like hierarchical morphology which consists of the self-assembly of 1D nanowires (~6 nm in diameter) and 2D ultrathin nanoflakes (~4.5 nm in thickness). A schematic illustration of its morphology formation is proposed.Pristine bismuth ferrite usually possesses weak magnetic properties (e.g., saturation magnetization Ms < 3 emu g-1) for practical magnetic separation applications. Herein, a superparamagnetic bismuth ferrite with coral-like hierarchical morphology (BFO-M) was fabricated through methanol solvothermal treatment of the as-prepared Bi2Fe4O9 nanoclusters (P-BFO). The BFO-M shows a higher Ms of ~31 emu g-1 compared to that of P-BFO treated in water (BFO-A), in ethanol (BFO-E) and in ethylene glycol (BFO-G). Compared to single-crystalline Bi2Fe4O9 (PS) and Bi2Fe4O9 clusters (NSP), BFO-M shows an excellent organic pollutant removal rate by virtue of its high adsorption capacity and catalytic activity when methyl orange (MO) is used as the model organic pollutant. BFO-M also exhibits good visible light photo-Fenton oxidation rates for pharmaceuticals and pesticides. Even at a low catalyst loading of 0.12 g L-1, the removal rate of organic pollutants (e.g., 5-fluorouracil, isoproturon) can be ~99% in 100 min under visible light irradiation. Besides, BFO-M is also a good adsorbent for different kinds of heavy metal ions (Pb(ii), Cr(iii), Cu(ii), As(v), etc.). For example, its maximal adsorption capacity for Pb(ii) is 214.5 mg g-1. The used BFO-M can be recovered via magnetic separation. The outstanding performances of BFO-M can be ascribed to its coral-like hierarchical morphology which consists of the self-assembly of 1D nanowires (~6 nm in diameter) and 2D ultrathin nanoflakes (~4.5 nm in thickness). A schematic illustration of its morphology formation is proposed. Electronic supplementary information (ESI) available. See DOI: 10.1039/c6nr03677e

Simultaneous quantification of withanolides in Withania somnifera by a validated high-performance thin-layer chromatographic method.

PubMed

Srivastava, Pooja; Tiwari, Neerja; Yadav, Akhilesh K; Kumar, Vijendra; Shanker, Karuna; Verma, Ram K; Gupta, Madan M; Gupta, Anil K; Khanuja, Suman P S

2008-01-01

This paper describes a sensitive, selective, specific, robust, and validated densitometric high-performance thin-layer chromatographic (HPTLC) method for the simultaneous determination of 3 key withanolides, namely, withaferin-A, 12-deoxywithastramonolide, and withanolide-A, in Ashwagandha (Withania somnifera) plant samples. The separation was performed on aluminum-backed silica gel 60F254 HPTLC plates using dichloromethane-methanol-acetone-diethyl ether (15 + 1 + 1 + 1, v/v/v/v) as the mobile phase. The withanolides were quantified by densitometry in the reflection/absorption mode at 230 nm. Precise and accurate quantification could be performed in the linear working concentration range of 66-330 ng/band with good correlation (r2 = 0.997, 0.999, and 0.996, respectively). The method was validated for recovery, precision, accuracy, robustness, limit of detection, limit of quantitation, and specificity according to International Conference on Harmonization guidelines. Specificity of quantification was confirmed using retention factor (Rf) values, UV-Vis spectral correlation, and electrospray ionization mass spectra of marker compounds in sample tracks.

Determination of three steroidal saponins from Ophiopogon japonicus (Liliaceae) via high-performance liquid chromatography with mass spectrometry.

PubMed

Wang, Yongyi; Xu, Jinzhong; Qu, Haibin

2013-01-01

A simple and accurate analytical method was developed for simultaneous quantification of three steroidal saponins in the roots of Ophiopogon japonicus via high-performance liquid chromatography (HPLC) with mass spectrometry (MS) in this study. Separation was performed on a Tigerkin C(18) column and detection was performed by mass spectrometry. A mobile phase consisted of 0.02% formic acid in water (v/v) and 0.02% formic acid in acetonitrile (v/v) was used with a flow rate of 0.5 mL min(-1). The quantitative HPLC-MS method was validated for linearity, precision, repeatability, stability, recovery, limits of detection and quantification. This developed method provides good linearity (r >0.9993), intra- and inter-day precisions (RSD <4.18%), repeatability (RSD <5.05%), stability (RSD <2.08%) and recovery (93.82-102.84%) for three steroidal saponins. It could be considered as a suitable quality control method for O. japonicus.

Stability-Indicating HPTLC Method for Studying Stress Degradation Behavior of Sulbutiamine HCl

PubMed Central

Farid, Nehal F.; Abdelwahab, Nada S.

2016-01-01

Sulbutiamine (SUL) is an ester of thiazides with neurotropic action. A new stability indicating HPTLC method has been developed and validated for the determination of SUL in the presence of different degradation products. The drug was subjected to different stress conditions following ICH strategy such as hydrolytic degradation (neutral, alkaline and acidic hydrolysis), oxidation, photodegradation and dry heat degradation. The drug demonstrated degradation under all decomposition conditions except neutral hydrolysis and dry heat, where the drug was completely degraded with 0.1 N NaOH, 1 N HCl and 30% H2O2 while it was partially degradaed by 0.1 N HCl, 3% H2O2 and UV light. Structure elucidation of the resulting degradation products was performed using ESI-Q-MS–MS. A well-defined peak for SUL was obtained at Rf = 0.46 and was completely separated from all obtained degradation products. Chromatographic separation was carried out on HPTLC aluminum plates precoated with silica gel 60 F254 using acetone–methylene chloride–ammonia buffer (pH 8.5 ± 0.2) (7:3:0.5, v/v) as a developing system. Densitometric scanning of the separated peaks was performed at 254 nm. System suitability testing parameters were calculated to ascertain the quality performance of the developed method. The method was validated with respect to USP guidelines regarding accuracy, precision, specificity, robustness and ruggedness. Good correlation coefficients were achieved in the range of 0.4–5.0 µg/band, and the limit of detection and limit of quantitation were found to be 0.11 and 0.33 µg/band, respectively. The utility of the suggested method was verified by application to Arcalion forte® tablets where no interference from additives was found. PMID:26759487

Graphene rectenna for efficient energy harvesting at terahertz frequencies

NASA Astrophysics Data System (ADS)

Dragoman, Mircea; Aldrigo, Martino

2016-09-01

In this paper, we propose a graphene rectenna that encompasses two distinct functions in a single device, namely, antenna and rectifier, which till now were two separate components. In this way, the rectenna realizes an efficient energy harvesting technique due to the absence of impedance mismatch between antenna and diode. In particular, we have obtained a maximum conversion efficiency of 58.43% at 897 GHz for the graphene rectenna on n-doped GaAs, which is a very good value, close to the performance of an RF harvesting system. A comparison with a classical metallic antenna with an HfO2-based metal-insulator-metal diode is also provided.

Numerical solution of 3D Navier-Stokes equations with upwind implicit schemes

NASA Technical Reports Server (NTRS)

Marx, Yves P.

1990-01-01

An upwind MUSCL type implicit scheme for the three-dimensional Navier-Stokes equations is presented. Comparison between different approximate Riemann solvers (Roe and Osher) are performed and the influence of the reconstructions schemes on the accuracy of the solution as well as on the convergence of the method is studied. A new limiter is introduced in order to remove the problems usually associated with non-linear upwind schemes. The implementation of a diagonal upwind implicit operator for the three-dimensional Navier-Stokes equations is also discussed. Finally the turbulence modeling is assessed. Good prediction of separated flows are demonstrated if a non-equilibrium turbulence model is used.

Evaluation of the UFXC32k photon-counting detector for pump-probe experiments using synchrotron radiation.

PubMed

Koziol, Anna; Bordessoule, Michel; Ciavardini, Alessandra; Dawiec, Arkadiusz; Da Silva, Paulo; Desjardins, Kewin; Grybos, Pawel; Kanoute, Brahim; Laulhe, Claire; Maj, Piotr; Menneglier, Claude; Mercere, Pascal; Orsini, Fabienne; Szczygiel, Robert

2018-03-01

This paper presents the performance of a single-photon-counting hybrid pixel X-ray detector with synchrotron radiation. The camera was evaluated with respect to time-resolved experiments, namely pump-probe-probe experiments held at SOLEIL. The UFXC camera shows very good energy resolution of around 1.5 keV and allows the minimum threshold setting to be as low as 3 keV keeping the high-count-rate capabilities. Measurements of a synchrotron characteristic filling mode prove the proper separation of an isolated bunch of photons and the usability of the detector in time-resolved experiments.

Discrimination of orbital angular momentum modes of the terahertz vortex beam using a diffractive mode transformer.

PubMed

Liu, Changming; Wei, Xuli; Niu, Liting; Wang, Kejia; Yang, Zhengang; Liu, Jinsong

2016-06-13

We present an efficient method to discriminate orbital angular momentum (OAM) of the terahertz (THz) vortex beam using a diffractive mode transformer. The mode transformer performs a log-polar coordinate transformation of the input THz vortex beam, which consists of two 3D-printed diffractive elements. A following lens separates each transformed OAM mode to a different lateral position in its focal plane. This method enables a simultaneous measurement over multiple OAM modes of the THz vortex beam. We experimentally demonstrate the measurement of seven individual OAM modes and two multiplexed OAM modes, which is in good agreement with simulations.

Polarization-independent dual-band terahertz metamaterial absorbers based on gold/parylene-C/silicide structure.

PubMed

Wen, Yongzheng; Ma, Wei; Bailey, Joe; Matmon, Guy; Yu, Xiaomei; Aeppli, Gabriel

2013-07-01

We design, fabricate, and characterize dual-band terahertz (THz) metamaterial absorbers with high absorption based on structures consisting of a cobalt silicide (Co-Si) ground plane, a parylene-C dielectric spacer, and a metal top layer. By combining two periodic metal resonators that couple separately within a single unit cell, a polarization-independent absorber with two distinct absorption peaks was obtained. By varying the thickness of the dielectric layer, we obtain absorptivity of 0.76 at 0.76 THz and 0.97 at 2.30 THz, which indicates the Co-Si ground plane absorbers present good performance.

Assessing Anxiety in Youth with the Multidimensional Anxiety Scale for Children (MASC)

PubMed Central

Wei, Chiaying; Hoff, Alexandra; Villabø, Marianne A.; Peterman, Jeremy; Kendall, Philip C.; Piacentini, John; McCracken, James; Walkup, John T.; Albano, Anne Marie; Rynn, Moira; Sherrill, Joel; Sakolsky, Dara; Birmaher, Boris; Ginsburg, Golda; Keaton, Courtney; Gosch, Elizabeth; Compton, Scott N.; March, John

2013-01-01

The present study examined the psychometric properties, including discriminant validity and clinical utility, of the youth self-report and parent-report forms of the Multidimensional Anxiety Scale for Children (MASC) among youth with anxiety disorders. The sample included parents and youth (N= 488, 49.6% male) ages 7 – 17 who participated in the Child/Adolescent Anxiety Multimodal Study (CAMS). Although the typical low agreement between parent and youth self-reports was found, the MASC evidenced good internal reliability across MASC subscales and informants. The main MASC subscales (i.e., Physical Symptoms, Harm Avoidance, Social Anxiety, and Separation/Panic) were examined. The Social Anxiety and Separation/Panic subscales were found to be significantly predictive of the presence and severity of social phobia and separation anxiety disorder, respectively. Using multiple informants improved the accuracy of prediction. The MASC subscales demonstrated good psychometric properties and clinical utilities in identifying youth with anxiety disorders. PMID:23845036

Impact of the revised International Prognostic Scoring System, cytogenetics and monosomal karyotype on outcome after allogeneic stem cell transplantation for myelodysplastic syndromes and secondary acute myeloid leukemia evolving from myelodysplastic syndromes: a retrospective multicenter study of the European Society of Blood and Marrow Transplantation

PubMed Central

Koenecke, Christian; Göhring, Gudrun; de Wreede, Liesbeth C.; van Biezen, Anja; Scheid, Christof; Volin, Liisa; Maertens, Johan; Finke, Jürgen; Schaap, Nicolaas; Robin, Marie; Passweg, Jakob; Cornelissen, Jan; Beelen, Dietrich; Heuser, Michael; de Witte, Theo; Kröger, Nicolaus

2015-01-01

The aim of this study was to determine the impact of the revised 5-group International Prognostic Scoring System cytogenetic classification on outcome after allogeneic stem cell transplantation in patients with myelodysplastic syndromes or secondary acute myeloid leukemia who were reported to the European Society for Blood and Marrow Transplantation database. A total of 903 patients had sufficient cytogenetic information available at stem cell transplantation to be classified according to the 5-group classification. Poor and very poor risk according to this classification was an independent predictor of shorter relapse-free survival (hazard ratio 1.40 and 2.14), overall survival (hazard ratio 1.38 and 2.14), and significantly higher cumulative incidence of relapse (hazard ratio 1.64 and 2.76), compared to patients with very good, good or intermediate risk. When comparing the predictive performance of a series of Cox models both for relapse-free survival and for overall survival, a model with simplified 5-group cytogenetics (merging very good, good and intermediate cytogenetics) performed best. Furthermore, monosomal karyotype is an additional negative predictor for outcome within patients of the poor, but not the very poor risk group of the 5-group classification. The revised International Prognostic Scoring System cytogenetic classification allows patients with myelodysplastic syndromes to be separated into three groups with clearly different outcomes after stem cell transplantation. Poor and very poor risk cytogenetics were strong predictors of poor patient outcome. The new cytogenetic classification added value to prediction of patient outcome compared to prediction models using only traditional risk factors or the 3-group International Prognostic Scoring System cytogenetic classification. PMID:25552702

Self-rated health among Greenlandic Inuit and Norwegian Sami adolescents: associated risk and protective correlates.

PubMed

Spein, Anna Rita; Pedersen, Cecilia Petrine; Silviken, Anne Cathrine; Melhus, Marita; Kvernmo, Siv Eli; Bjerregaard, Peter

2013-01-01

Self-rated health (SRH) and associated risk and protective correlates were investigated among two indigenous adolescent populations, Greenlandic Inuit and Norwegian Sami. Cross-sectional data were collected from "Well-being among Youth in Greenland" (WBYG) and "The Norwegian Arctic Adolescent Health Study" (NAAHS), conducted during 2003-2005 and comprising 10th and 11th graders, 378 Inuit and 350 Sami. SRH was assessed by one single item, using a 4-point and 5-point scale for NAAHS and WBYG, respectively. Logistic regressions were performed separately for each indigenous group using a dichotomous measure with "very good" (NAAHS) and "very good/good" (WBYG) as reference categories. We simultaneously controlled for various socio-demographics, risk correlates (drinking, smoking, violence and suicidal behaviour) and protective correlates (physical activity, well-being in school, number of close friends and adolescent-parent relationship). A majority of both Inuit (62%) and Sami (89%) youth reported "good" or "very good" SRH. The proportion of "poor/fair/not so good" SRH was three times higher among Inuit than Sami (38% vs. 11%, p≤0.001). Significantly more Inuit females than males reported "poor/fair" SRH (44% vs. 29%, p≤0.05), while no gender differences occurred among Sami (12% vs. 9%, p≤0.08). In both indigenous groups, suicidal thoughts (risk) and physical activity (protective) were associated with poor and good SRH, respectively. In accordance with other studies of indigenous adolescents, suicidal thoughts were strongly associated with poorer SRH among Sami and Inuit. The Inuit-Sami differences in SRH could partly be due to higher "risk" and lower "protective" correlates among Inuit than Sami. The positive impact of physical activity on SRH needs to be targeted in future intervention programs.

Rapid screening, identification, and purification of neuraminidase inhibitors from Lithospermum erythrorhizon Sieb.et Zucc. by ultrafiltration with HPLC-ESI-TOF-MS combined with semipreparative HPLC.

PubMed

Zhang, Minmin; Zhao, Hengqiang; Zhao, Zhiguo; Yan, Huijiao; Lv, Ruimin; Cui, Li; Yuan, Jinpeng; Wang, Daijie; Geng, Yanling; Liu, Daicheng; Wang, Xiao

2016-06-01

We put forward an efficient strategy based on bioassay guidance for the rapid screening, identification, and purification of the neuraminidase inhibitors from traditional Chinese medicines, and apply to the discovery of anti-influenza components from Lithospermiun erythrorhizon Sieb.et Zucc. Ultrafiltration with high-performance liquid chromatography and electrospray ionization time-of-flight mass spectrometry was employed for the rapid screening and preliminarily identification of anti-influenza components from Zicao. Semipreparative high-performance liquid chromatography was used for the rapid separation and purification of the target compounds. NMR spectroscopy, mass spectrometry, and UV spectroscopy were used for further structural identification, and the activity of the compounds was verified by in vitro assay. Five compounds were found to have neuraminidase inhibitory activity by this method. Subsequently, the five compounds were separated by semipreparative high-performance liquid chromatography with the purity over 98% for all of them by high-performance liquid chromatography test. Combined with the NMR spectroscopy, mass spectrometry, and UV spectroscopy data, they were identified as alkannin, acetylalkannin, isobutyrylalkannin, β,β-dimethylacryloylalkannin and isovalerylalkannin. The in vitro assay showed that all five compounds had good neuraminidase inhibitory activities. These results suggested that the method is highly efficient, and it can provide platform and methodology supports for the rapid discovery of anti-influenza active ingredients from complex Chinese herbal medicines. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Do quality indicators for general practice teaching practices predict good outcomes for students?

PubMed

Bartlett, Maggie; Potts, Jessica; McKinley, Bob

2016-07-01

Keele medical students spend 113 days in general practices over our five-year programme. We collect practice data thought to indicate good quality teaching. We explored the relationships between these data and two outcomes for students; Objective Structured Clinical Examination (OSCE) scores and feedback regarding the placements. Though both are surrogate markers of good teaching, they are widely used. We collated practice and outcome data for one academic year. Two separate statistical analyses were carried out: (1) to determine how much of the variation seen in the OSCE scores was due to the effect of the practice and how much to the individual student. (2) to identify practice characteristics with a relationship to student feedback scores. (1) OSCE performance: 268 students in 90 practices: six quality indicators independently influenced the OSCE score, though without linear relationships and not to statistical significance. (2) Student satisfaction: 144 students in 69 practices: student feedback scores are not influenced by practice characteristics. The relationships between the quality indicators we collect for practices and outcomes for students are not clear. It may be that neither the quality indicators nor the outcome measures are reliable enough to inform decisions about practices' suitability for teaching.

An implantation of multifocal lenses LS-313 MF30, Mplus and MplusX models, during and after posterior vitrectomy in patients treated for various diseases of the retina.

PubMed

Cywinski, Adam; Piwonska-Lobermajer, Anna; Penter, Sandra

2016-08-01

A retrospective analysis of visual function and postoperative complaints in patients after posterior vitrectomy and multifocal Mplus or MplusX intraocular lens implantation. 14 patients (14 eyes) were enrolled in the study. All patients underwent posterior vitrectomy due to underlying retinal pathologies. A combined procedure of phacovitrectomy was performed in some patients, whereas others underwent a separate cataract extraction as a second stage of treatment. The Mplus or MplusX intraocular lenses were implanted in all cases and the postoperative visual function and patient complaints were analysed. Multifocal lens explantation was not necessary in any case. Good uncorrected distance and near visual acuity was achieved in most cases. When implanted prior to vitrectomy, the intraocular lenses did not limit the view into the posterior segment, so precise manipulations within the macula and peripheral retina were feasible. The right choice between Mplus and MplusX minimises the rate of postoperative complaints. Conslusions: The multifocal Mplus and MplusX intraocular lenses offer a good alternative for patients who need posterior vitrectomy and still want to achieve good uncorrected distance and near visual acuity.

Monetary and affective judgments of consumer goods: modes of evaluation matter.

PubMed

Seta, John J; Seta, Catherine E; McCormick, Michael; Gallagher, Ashleigh H

2014-01-01

Participants who evaluated 2 positively valued items separately reported more positive attraction (using affective and monetary measures) than those who evaluated the same two items as a unit. In Experiments 1-3, this separate/unitary evaluation effect was obtained when participants evaluated products that they were purchasing for a friend. Similar findings were obtained in Experiments 4 and 5 when we considered the amount participants were willing to spend to purchase insurance for items that they currently owned. The averaging/summation model was contrasted with several theoretical perspectives and implicated averaging and summation integration processes in how items are evaluated. The procedural and theoretical similarities and differences between this work and related research on unpacking, comparison processes, public goods, and price bundling are discussed. Overall, the results support the operation of integration processes and contribute to an understanding of how these processes influence the evaluation and valuation of private goods.

A Novel Sensitive Luminescence Probe Microspheres for Rapid and Efficient Detection of τ-Fluvalinate in Taihu Lake

PubMed Central

Wang, Jixiang; Wang, Yunyun; Qiu, Hao; Sun, Lin; Dai, Xiaohui; Pan, Jianming; Yan, Yongsheng

2017-01-01

Fluorescent molecularly imprinted polymers have shown great promise in biological or chemical separations and detection, due to their high stability, selectivity and sensitivity. In this work, fluorescent molecularly imprinted microsphere was synthesized via precipitation polymerization, which could separate efficiently and rapidly detect τ-fluvalinate (a toxic insecticide) in water samples, was reported. The fluorescent imprinted sensor showed excellent stability, outstanding selectivity and the limit of detection low to 12.14 nM, good regeneration ability which still kept good sensitivity after 8 cycling experiments and fluorescence quenching mechanism was illustrated in details. In addition, the fluorescent sensor was further used to detect τ-fluvalinate in real samples from Taihu Lake. Despite the relatively complex components of the environment water, the fluorescent imprinted microspheres sitll showed good recovery, clearly demonstrating the potental value of this smart sensor nanomaterial in environment monitoring. PMID:28485402

When Parents Divorce. Caring about Kids.

ERIC Educational Resources Information Center

Stapleton, Constance; MacCormack, Norma

This pamphlet, part of a series designed to help parents care for themselves and their children while promoting good mental health, deals with ways in which children are affected by divorce and how they learn to cope with the subsequent separation and changes. Advice for preparing children for the separation and divorce includes suggestions on how…

Critical rotational speed model of the rotating roll electrode in corona electrostatic separation for recycling waste printed circuit boards.

PubMed

Li, Jia; Lu, Hongzhou; Xu, Zhenming; Zhou, Yaohe

2008-06-15

Waste printed circuit board (PCB) is increasing worldwide. The corona electrostatic separation (CES) was an effective and environmental protection way to recycle resource from waste PCBs. The aim of this paper is to analyze the main factor (rotational speed) that affects the efficiency of CES from the point of view of electrostatics and mechanics. A quantitative method for analyzing the affection of rotational speed was studied and the model for separating flat nonmetal particles in waste PCBs was established. The conception of "charging critical rotational speed" and "detaching critical rotational speed" were presented. Experiments with the waste PCBs verified the theoretical model, and the experimental results were in good agreement with the theoretical model. The results indicated that the purity and recycle percentage of materials got a good level when the rotational speed was about 70 rpm and the critical rotational speed of small particles was higher than big particles. The model can guide the definition of operator parameter and the design of CES, which are needed for the development of any new application of the electrostatic separation method.

Removal of algal blooms from freshwater by the coagulation-magnetic separation method.

PubMed

Liu, Dan; Wang, Peng; Wei, Guanran; Dong, Wenbo; Hui, Franck

2013-01-01

This research investigated the feasibility of changing waste into useful materials for water treatment and proposed a coagulation-magnetic separation technique. This technique was rapid and highly effective for clearing up harmful algal blooms in freshwater and mitigating lake eutrophication. A magnetic coagulant was synthesized by compounding acid-modified fly ash with magnetite (Fe(3)O(4)). Its removal effects on algal cells and dissolved organics in water were studied. After mixing, coagulation, and magnetic separation, the flocs obtained from the magnet surface were examined by SEM. Treated samples were withdrawn for the content determination of chlorophyll-a, turbidity, chemical oxygen demand (COD), total nitrogen, and total phosphorus. More than 99 % of algal cells were removed within 5 min after the addition of magnetic coagulant at optimal loadings (200 mg L(-1)). The removal efficiencies of COD, total nitrogen, and phosphorus were 93, 91, and 94 %, respectively. The mechanism of algal removal explored preliminarily showed that the magnetic coagulant played multiple roles in mesoporous adsorption, netting and bridging, as well as high magnetic responsiveness to a magnetic field. The magnetic-coagulation separation method can rapidly and effectively remove algae from water bodies and greatly mitigate eutrophication of freshwater using a new magnetic coagulant. The method has good performance, is low cost, can turn waste into something valuable, and provides reference and directions for future pilot and production scale-ups.

Stretchable Lithium-Ion Batteries Enabled by Device-Scaled Wavy Structure and Elastic-Sticky Separator

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

Liu, Wei; Chen, Jun; Chen, Zheng

Fast developments and substantial achievements have been shaping the field of wearable electronic devices, resulting in the persistent requirement for stretchable lithium-ion batteries (LIBs). Despite recent progress in stretchable electrodes, stretching full batteries, including electrodes, separator, and sealing material, remains a great challenge. Here, a simple design concept for stretchable LIBs via a wavy structure at the full battery device scale is reported. All components including the package are capable of being reversibly stretched by folding the entire pouch cell into a wavy shape with polydimethylsiloxane filled in each valley region. In addition, the stretchable, sticky, and porous polyurethane/poly(vinylidene fluoride)more » membrane is adopted as a separator for the first time, which can maintain intimate contact between electrodes and separator to continuously secure ion pathway under dynamic state. Commercial cathode, anode, and package can be utilized in this rationally designed wavy battery to enable stretchability. The results indicate good electrochemical performances and long-term stability at repeatable release–stretch cycles. A high areal capacity of 3.6 mA h cm -2 and energy density of up to 172 W h L -1 can be achieved for the wavy battery. The promising results of the cost-effective wavy battery with high stretchability shed light on the development of stretchable energy storages.« less

Stretchable Lithium-Ion Batteries Enabled by Device-Scaled Wavy Structure and Elastic-Sticky Separator

DOE PAGES

Liu, Wei; Chen, Jun; Chen, Zheng; ...

2017-07-17

Fast developments and substantial achievements have been shaping the field of wearable electronic devices, resulting in the persistent requirement for stretchable lithium-ion batteries (LIBs). Despite recent progress in stretchable electrodes, stretching full batteries, including electrodes, separator, and sealing material, remains a great challenge. Here, a simple design concept for stretchable LIBs via a wavy structure at the full battery device scale is reported. All components including the package are capable of being reversibly stretched by folding the entire pouch cell into a wavy shape with polydimethylsiloxane filled in each valley region. In addition, the stretchable, sticky, and porous polyurethane/poly(vinylidene fluoride)more » membrane is adopted as a separator for the first time, which can maintain intimate contact between electrodes and separator to continuously secure ion pathway under dynamic state. Commercial cathode, anode, and package can be utilized in this rationally designed wavy battery to enable stretchability. The results indicate good electrochemical performances and long-term stability at repeatable release–stretch cycles. A high areal capacity of 3.6 mA h cm -2 and energy density of up to 172 W h L -1 can be achieved for the wavy battery. The promising results of the cost-effective wavy battery with high stretchability shed light on the development of stretchable energy storages.« less

Massive separation around bluff bodies: comparisons among different cfd solvers and turbulence models

NASA Astrophysics Data System (ADS)

Armenio, Vincenzo; Fakhari, Ahmad; Petronio, Andrea; Padovan, Roberta; Pittaluga, Chiara; Caprino, Giovanni

2015-11-01

Massive flow separation is ubiquitous in industrial applications, ruling drag and hydrodynamic noise. In spite of considerable efforts, its numerical prediction still represents a challenge for CFD models in use in engineering. Aside commercial software, over the latter years the opensource software OpenFOAMR (OF) has emerged as a valid tool for prediction of complex industrial flows. In the present work, we simulate two flows representative of a class of situations occurring in industrial problems: the flow around sphere and that around a wall-mounted square cylinder at Re = 10000 . We compare the performance two different tools, namely OF and ANSYS CFX 15.0 (CFX) using different unstructured grids and turbulence models. The grids have been generated using SNAPPYHEXMESH and ANSYS ICEM CFD 15.0 with different near wall resolutions. The codes have been run in a RANS mode using k - ɛ model (OF) and SST - k - ω (CFX) with and without wall-layer models. OF has been also used in LES, WMLES and DES mode. Regarding the sphere, RANS models were not able to catch separation, while good prediction of separation and distribution of stresses over the surface were obtained using LES, WMLES and DES. Results for the second test case are currently under analysis. Financial support from COSMO ``cfd open source per opera mortta'' PAR FSC 2007-2013, Friuli Venezia Giulia.

Separator-Integrated, Reversely Connectable Symmetric Lithium-Ion Battery.

PubMed

Wang, Yuhang; Zeng, Jiren; Cui, Xiaoqi; Zhang, Lijuan; Zheng, Gengfeng

2016-02-24

A separator-integrated, reversely connectable, symmetric lithium-ion battery is developed based on carbon-coated Li3V2(PO4)3 nanoparticles and polyvinylidene fluoride-treated separators. The Li3V2(PO4)3 nanoparticles are synthesized via a facile solution route followed by calcination in Ar/H2 atmosphere. Sucrose solution is used as the carbon source for uniform carbon coating on the Li3V2(PO4)3 nanoparticles. Both the carbon and the polyvinylidene fluoride treatments substantially improve the cycling life of the symmetric battery by preventing the dissolution and shuttle of the electroactive Li3V2(PO4)3. The obtained symmetric full cell exhibits a reversible capacity of ≈ 87 mA h g(-1), good cycling stability, and capacity retention of ≈ 70% after 70 cycles. In addition, this type of symmetric full cell can be operated in both forward and reverse connection modes, without any influence on the cycling of the battery. Furthermore, a new separator integration approach is demonstrated, which enables the direct deposition of electroactive materials for the battery assembly and does not affect the electrochemical performance. A 10-tandem-cell battery assembled without differentiating the electrode polarity exhibits a low thickness of ≈ 4.8 mm and a high output voltage of 20.8 V. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Semiautomated object-based classification of rain-induced landslides with VHR multispectral images on Madeira Island

NASA Astrophysics Data System (ADS)

Heleno, Sandra; Matias, Magda; Pina, Pedro; Sousa, António Jorge

2016-04-01

A method for semiautomated landslide detection and mapping, with the ability to separate source and run-out areas, is presented in this paper. It combines object-based image analysis and a support vector machine classifier and is tested using a GeoEye-1 multispectral image, sensed 3 days after a major damaging landslide event that occurred on Madeira Island (20 February 2010), and a pre-event lidar digital terrain model. The testing is developed in a 15 km2 wide study area, where 95 % of the number of landslides scars are detected by this supervised approach. The classifier presents a good performance in the delineation of the overall landslide area, with commission errors below 26 % and omission errors below 24 %. In addition, fair results are achieved in the separation of the source from the run-out landslide areas, although in less illuminated slopes this discrimination is less effective than in sunnier, east-facing slopes.

Directional coupler based on an elliptic cylindrical nanowire hybrid plasmonic waveguide.

PubMed

Zeng, Dezheng; Zhang, Li; Xiong, Qiulin; Ma, Junxian

2018-06-01

We present what we believe is a novel directional coupler based on an elliptic cylindrical nanowire hybrid plasmonic waveguide. Using the finite element method, the electric field distributions of y-polarized symmetric and antisymmetric modes of the coupler are compared, and the coupling and transmission characteristics are analyzed; then the optimized separation distance between the two parallel waveguides, 100 nm, is obtained. This optimized architecture fits in the weak coupling regime. Furthermore, the energy transfer is studied, and the performances of the directional coupler are evaluated, including excess loss, coupling degree, and directionality. The results show that when the separation distance is set to 100 nm, the coupling length reaches the shorter value of 1.646 μm, and the propagation loss is as low as 0.076 dB/μm, and the maximum energy transfer can reach 80%. The proposed directional coupler features good energy confinement, ultracompact and low propagation loss, which has potential application in dense photonic-integrated circuits and other photonic devices.

[Multi-parent families as "normal" families--segregation and parent-child-alienation after separation and divorce].

PubMed

Napp-Peters, Anneke

2005-12-01

Decisive for the question as to how children cope with their parents' divorce is whether or not the parents continue to perform their parental role together even after separation, or have at least made arrangements for the child to maintain a good relationship with each parent. These are the findings of a longitudinal study of 150 postdivorce families. The case of a multi-parent family after remarriage, which sees itself as a "normal" family and segregates the visiting parent, shows what consequences the breakdown of parent-child relationships has for the psychological health and the development of children. Alienation and long-term disruption of the contact between child and visiting parent is a phenomenon which the psychiatric and psychotherapeutic professions are increasingly confronted with. The American child psychiatrist R. A. Gardner has introduced the term "Parental Alienation Syndrome (PAS)" to encompass this childhood disorder that arises almost exclusively in the context of child-custody disputes.

Gas chromatography on wall-coated open-tubular columns with ionic liquid stationary phases.

PubMed

Poole, Colin F; Lenca, Nicole

2014-08-29

Ionic liquids have moved from novel to practical stationary phases for gas chromatography with an increasing portfolio of applications. Ionic liquids complement conventional stationary phases because of a combination of thermophysical and solvation properties that only exist for ionic solvents. Their high thermal stability and low vapor pressure makes them suitable as polar stationary phases for separations requiring high temperatures. Ionic liquids are good solvents and can be used to expand the chemical space for separations. They are the only stationary phases with significant hydrogen-bond acidity in common use; they extend the hydrogen-bond basicity of conventional stationary phases; they are as dipolar/polarizable as the most polar conventional stationary phases; and some ionic liquids are significantly less cohesive than conventional polar stationary phases. Problems in column coating techniques and related low column performance, column activity, and stationary phase reactivity require further exploration as the reasons for these features are poorly understood at present. Copyright © 2014 Elsevier B.V. All rights reserved.

Analysis of wax esters by silver-ion high-performance liquid chromatography-tandem mass spectrometry.

PubMed

Vrkoslav, Vladimír; Urbanová, Klára; Háková, Matina; Cvačka, Josef

2013-08-09

Wax esters (WEs), esters of long-chain fatty acids and long-chain alcohols, were analysed by Ag-HPLC/APCI-MS/MS. Two ChromSpher Lipids columns connected in series (a total length of 50cm) and hexane-2-propanol-acetonitrile mobile phases were used to achieve good separation of the molecular species. The chromatographic behaviour of WEs was studied under optimised conditions: retention increased with the number of double bonds and with the temperature (15-35°C); retention times were affected by the double-bond position, trans isomers eluted earlier than cis isomers, and the WEs were partially separated depending on the aliphatic-chain length. The WEs provided simple APCI spectra with [M+H](+) ions, the MS/MS spectra showed fragments, which allowed their identification. The method was applied for an analysis of the WE mixtures from jojoba oil and human hair and the results were compared with analogous data from an optimised RP-HPLC system. Copyright © 2013 Elsevier B.V. All rights reserved.

Oil flow at the scroll compressor discharge: visualization and CFD simulation

NASA Astrophysics Data System (ADS)

Xu, Jiu; Hrnjak, Pega

2017-08-01

Oil is important to the compressor but has other side effect on the refrigeration system performance. Discharge valves located in the compressor plenum are the gateway for the oil when leaving the compressor and circulate in the system. The space in between: the compressor discharge plenum has the potential to separate the oil mist and reduce the oil circulation ratio (OCR) in the system. In order to provide information for building incorporated separation feature for the oil flow near the compressor discharge, video processing method is used to quantify the oil droplets movement and distribution. Also, CFD discrete phase model gives the numerical approach to study the oil flow inside compressor plenum. Oil droplet size distributions are given by visualization and simulation and the results show a good agreement. The mass balance and spatial distribution are also discussed and compared with experimental results. The verification shows that discrete phase model has the potential to simulate the oil droplet flow inside the compressor.

Detection of malondialdehyde in processed meat products without interference from the ingredients.

PubMed

Jung, Samooel; Nam, Ki Chang; Jo, Cheorun

2016-10-15

Our aim was to develop a method for accurate quantification of malondialdehyde (MDA) in meat products. MDA content of uncured ground pork (Control); ground pork cured with sodium nitrite (Nitrite); and ground pork cured with sodium nitrite, sodium chloride, sodium pyrophosphate, maltodextrin, and a sausage seasoning (Mix) was measured by the 2-thiobarbituric acid (TBA) assay with MDA extraction by trichloroacetic acid (method A) and two high-performance liquid chromatography (HPLC) methods: i) HPLC separation of the MDA-dinitrophenyl hydrazine adduct (method B) and ii) HPLC separation of MDA (method C) after MDA extraction with acetonitrile. Methods A and B could not quantify MDA accurately in groups Nitrite and Mix. Nevertheless, MDA in groups Control, Nitrite, and Mix was accurately quantified by method C with good recovery. Therefore, direct MDA quantification by HPLC after MDA extraction with acetonitrile (method C) is useful for accurate measurement of MDA content in processed meat products. Copyright © 2016 Elsevier Ltd. All rights reserved.

Conversion of hydrophilic SiOC nanofibrous membrane to robust hydrophobic materials by introducing palladium

NASA Astrophysics Data System (ADS)

Wu, Nan; Wan, Lynn Yuqin; Wang, Yingde; Ko, Frank

2017-12-01

Hydrophobic ceramic nanofibrous membranes have wide applications in the fields of high-temperature filters, oil/water separators, catalyst supports and membrane reactors, for their water repellency property, self-cleaning capability, good environmental stability and long life span. In this work, we fabricated an inherently hydrophobic ceramic nanofiber membrane without any surface modification through pyrolysis of electrospun polycarbosilane nanofibers. The hydrophobicity was introduced by the hierarchical microstructure formed on the surface of the nanofibers and the special surface composition by the addition of trace amounts of palladium. Furthermore, the flexible ceramic mats demonstrated robust chemical resistance properties with consistent hydrophobicity over the entire pH value range and effective water-in-oil emulsion separation performance. Interestingly, a highly cohesive force was found between water droplet and the ceramic membranes, suggesting their great potentials in micro-liquid transportation. This work provides a new route for adjusting the composition of ceramic surface and flexible, recyclable and multifunctional ceramic fibrous membranes for utilization in harsh environments.

Validation of a HPLC method for determination of hydroxymethylfurfural in crude palm oil.

PubMed

Ariffin, Abdul Azis; Ghazali, H M; Kavousi, Parviz

2014-07-01

For the first time 5-hydroxymethyl-2-furaldehyde (HMF) was separated from crude palm oil (CPO), and its authenticity was determined using an RP-HPLC method. Separation was accomplished with isocratic elution of a mobile phase comprising water and methanol (92:8 v/v) on a Purospher Star RP-18e column (250mm×4.6mm, 5.0μm). The flow rate was adjusted to 1ml/min and detection was performed at 284nm. The method was validated, and results obtained exhibit a good recovery (95.58% to 98.39%). Assessment of precision showed that the relative standard deviations (RSD%) of retention times and peak areas of spiked samples were less than 0.59% and 2.66%, respectively. Further, the limit of detection (LOD) and LOQ were 0.02, 0.05mg/kg, respectively, and the response was linear across the applied ranges. The crude palm oil samples analysed exhibited HMF content less than 2.27mg/kg. Copyright © 2014 Elsevier Ltd. All rights reserved.

Optimization of operation conditions for the startup of aerobic granular sludge reactors biologically removing carbon, nitrogen, and phosphorous.

PubMed

Lochmatter, Samuel; Holliger, Christof

2014-08-01

The transformation of conventional flocculent sludge to aerobic granular sludge (AGS) biologically removing carbon, nitrogen and phosphorus (COD, N, P) is still a main challenge in startup of AGS sequencing batch reactors (AGS-SBRs). On the one hand a rapid granulation is desired, on the other hand good biological nutrient removal capacities have to be maintained. So far, several operation parameters have been studied separately, which makes it difficult to compare their impacts. We investigated seven operation parameters in parallel by applying a Plackett-Burman experimental design approach with the aim to propose an optimized startup strategy. Five out of the seven tested parameters had a significant impact on the startup duration. The conditions identified to allow a rapid startup of AGS-SBRs with good nutrient removal performances were (i) alternation of high and low dissolved oxygen phases during aeration, (ii) a settling strategy avoiding too high biomass washout during the first weeks of reactor operation, (iii) adaptation of the contaminant load in the early stage of the startup in order to ensure that all soluble COD was consumed before the beginning of the aeration phase, (iv) a temperature of 20 °C, and (v) a neutral pH. Under such conditions, it took less than 30 days to produce granular sludge with high removal performances for COD, N, and P. A control run using this optimized startup strategy produced again AGS with good nutrient removal performances within four weeks and the system was stable during the additional operation period of more than 50 days. Copyright © 2014 Elsevier Ltd. All rights reserved.

TiO2 Nanorod Arrays Based Self-Powered UV Photodetector: Heterojunction with NiO Nanoflakes and Enhanced UV Photoresponse.

PubMed

Gao, Yanyan; Xu, Jianping; Shi, Shaobo; Dong, Hong; Cheng, Yahui; Wei, Chengtai; Zhang, Xiaosong; Yin, Shougen; Li, Lan

2018-04-04

The self-powered ultraviolet photodetectors (UV PDs) have attracted increasing attention due to their potential applications without consuming any external power. It is important to obtain the high-performance self-powered UV PDs by a simple method for the practical application. Herein, TiO 2 nanorod arrays (NRs) were synthesized by hydrothermal method, which were integrated with p-type NiO nanoflakes to realize a high performance pn heterojunction for the efficient UV photodetection. TiO x thin film can improve the morphological and carrier transport properties of TiO 2 NRs and decrease the surface and defect states, resulting in the enhanced photocurrent of the devices. NiO/TiO 2 nanostructural heterojunctions show excellent rectifying characteristics (rectification ratio of 2.52 × 10 4 and 1.45 × 10 5 for NiO/TiO 2 NRs and NiO/TiO 2 NRs/TiO x , respectively) with a very low reverse saturation current. The PDs based on the heterojunctions exhibit good spectral selectivity, high photoresponsivity, and fast response and recovery speeds without external applied bias under the weak light radiation. The devices demonstrate good stability and repeatability under UV light radiation. The self-powered performance could be attributed to the proper built-in electric field of the heterojunction. TiO 2 NRs and NiO nanoflakes construct the well-aligned energy-band structure. The enhanced responsivity and detectivity for the devices with TiO x thin films is related to the increased interfacial charge separation efficiency, reduced carrier recombination, and relatively good electron transport of TiO 2 NRs.

An in situ polymerization approach for the synthesis of superhydrophobic and superoleophilic nanofibrous membranes for oil-water separation

NASA Astrophysics Data System (ADS)

Shang, Yanwei; Si, Yang; Raza, Aikifa; Yang, Liping; Mao, Xue; Ding, Bin; Yu, Jianyong

2012-11-01

Superhydrophobic and superoleophilic nanofibrous membranes exhibiting robust oil-water separation performance were prepared by a facile combination of electrospun cellulose acetate (CA) nanofibers and a novel in situ polymerized fluorinated polybenzoxazine (F-PBZ) functional layer that incorporated silica nanoparticles (SiO2 NPs). By employing the F-PBZ/SiO2 NPs modification, the pristine hydrophilic CA nanofibrous membranes were endowed with a superhydrophobicity with the water contact angle of 161° and a superoleophilicity with the oil contact angle of 3°. Surface morphological studies have indicated that the wettability of resultant membranes could be manipulated by tuning the surface composition as well as the hierarchical structures. The quantitative hierarchical roughness analysis using the N2 adsorption method has confirmed the major contribution of SiO2 NPs on enhancing the porous structure, and a detailed correlation between roughness and solid-liquid interface pinning is proposed. Furthermore, the as-prepared membranes exhibited fast and efficient separation for oil-water mixtures and excellent stability over a wide range of pH conditions, which would make them a good candidate in industrial oil-polluted water treatments and oil spill cleanup, and also provided a new insight into the design and development of functional nanofibrous membranes through F-PBZ modification.Superhydrophobic and superoleophilic nanofibrous membranes exhibiting robust oil-water separation performance were prepared by a facile combination of electrospun cellulose acetate (CA) nanofibers and a novel in situ polymerized fluorinated polybenzoxazine (F-PBZ) functional layer that incorporated silica nanoparticles (SiO2 NPs). By employing the F-PBZ/SiO2 NPs modification, the pristine hydrophilic CA nanofibrous membranes were endowed with a superhydrophobicity with the water contact angle of 161° and a superoleophilicity with the oil contact angle of 3°. Surface morphological studies have indicated that the wettability of resultant membranes could be manipulated by tuning the surface composition as well as the hierarchical structures. The quantitative hierarchical roughness analysis using the N2 adsorption method has confirmed the major contribution of SiO2 NPs on enhancing the porous structure, and a detailed correlation between roughness and solid-liquid interface pinning is proposed. Furthermore, the as-prepared membranes exhibited fast and efficient separation for oil-water mixtures and excellent stability over a wide range of pH conditions, which would make them a good candidate in industrial oil-polluted water treatments and oil spill cleanup, and also provided a new insight into the design and development of functional nanofibrous membranes through F-PBZ modification. Electronic supplementary information (ESI) available: Detailed synthesis and structural confirmation of BAF-tfa, FT-IR results, OCA results and Movie S1. See DOI: 10.1039/c2nr33063f

Validation of the updated ArthroS simulator: face and construct validity of a passive haptic virtual reality simulator with novel performance metrics.

PubMed

Garfjeld Roberts, Patrick; Guyver, Paul; Baldwin, Mathew; Akhtar, Kash; Alvand, Abtin; Price, Andrew J; Rees, Jonathan L

2017-02-01

To assess the construct and face validity of ArthroS, a passive haptic VR simulator. A secondary aim was to evaluate the novel performance metrics produced by this simulator. Two groups of 30 participants, each divided into novice, intermediate or expert based on arthroscopic experience, completed three separate tasks on either the knee or shoulder module of the simulator. Performance was recorded using 12 automatically generated performance metrics and video footage of the arthroscopic procedures. The videos were blindly assessed using a validated global rating scale (GRS). Participants completed a survey about the simulator's realism and training utility. This new simulator demonstrated construct validity of its tasks when evaluated against a GRS (p ≤ 0.003 in all cases). Regarding it's automatically generated performance metrics, established outputs such as time taken (p ≤ 0.001) and instrument path length (p ≤ 0.007) also demonstrated good construct validity. However, two-thirds of the proposed 'novel metrics' the simulator reports could not distinguish participants based on arthroscopic experience. Face validity assessment rated the simulator as a realistic and useful tool for trainees, but the passive haptic feedback (a key feature of this simulator) is rated as less realistic. The ArthroS simulator has good task construct validity based on established objective outputs, but some of the novel performance metrics could not distinguish between surgical experience. The passive haptic feedback of the simulator also needs improvement. If simulators could offer automated and validated performance feedback, this would facilitate improvements in the delivery of training by allowing trainees to practise and self-assess.

The Case for the L-Shaped Classroom.

ERIC Educational Resources Information Center

Dyck, James A.

1994-01-01

Classroom shape is an important variable in educational quality. The traditional squat rectangle may be counterproductive to the learning process. The fat L-shaped classroom, compared to H, X, and T shapes, offers good separation, is more compact, and provides good visibility and ease of movement for the teacher. It has excellent nesting…

Good Work! Instructor's Guide. Revised. Employability Skills Series.

ERIC Educational Resources Information Center

Farrow, Douglas R.

This instructor's guide accompanies the student booklet/unit on good work habits/behaviors in the Employability Skills Series. (The student booklet is available separately as CE 031 161.) It first discusses the Employability Skills Series. A section on administering the unit details purpose of the unit and major concepts to be developed, lists…

Building Good New Ideas; Mixing Metaphors and Media: A Digital and Analog Elixir.

ERIC Educational Resources Information Center

McKenzie, Jamie

2001-01-01

Includes two articles. Topics include skills needed to teach young people how to build their own good ideas instead of cutting and pasting the ideas of others; and the trend toward false dichotomies and the dangers created when separating complex issues into two contrasting sides or choices. (LRW)

Can Suicide Be a Good Death?

ERIC Educational Resources Information Center

Lester, David

2006-01-01

The issue of whether suicide can be a good death was separated into two different questions: (1) can suicide be an appropriate death, and (2) can suicide be a rational death? Several definitions of an "appropriate" death were proposed, and suicide was seen as potentially appropriate. Similarly, several criteria for rationality were proposed and…

Preliminary appraisal of the reliability and validity of the Colorado State University Feline Acute Pain Scale.

PubMed

Shipley, Hilary; Guedes, Alonso; Graham, Lynelle; Goudie-DeAngelis, Elizabeth; Wendt-Hornickle, Erin

2018-05-01

Objectives The objective of this study was to determine the inter-rater reliability and convergent validity of the Colorado State University Feline Acute Pain Scale (CSU-FAPS) in a preliminary appraisal of its performance in a clinical teaching setting. Methods Sixty-eight female cats were assessed for pain after ovariohysterectomy. A cohort of 21 cats was examined independently by four raters (two board-certified anesthesiologists and two anesthesia residents) with the CSU-FAPS, and intra-class correlation coefficient (ICC) was used to determine inter-rater reliability. Weighted Cohen's kappa was used to determine inter-rater reliability centered on the 'need to reassess analgesic plan' (dichotomous scale). A separate cohort of 47 cats was evaluated independently by two raters (one board-certified anesthesiologist and one veterinary small animal rotating intern) using the CSU-FAPS and the Glasgow Composite Measure Pain Scale (CMPS-Feline), and Spearman rank-order correlation was determined to assess convergent validity. Reliability was interpreted using Altman's classification as very good, good, moderate, fair and poor. Validity was considered adequate if correlation coefficients were between 0.4 and 0.8. Results The ICC was 0.61 for anesthesiologists and 0.67 for residents, indicating good reliability. Weighted Cohen's kappa was 0.79 for anesthesiologists and 0.44 for residents, indicating moderate to good reliability. The Spearman rank correlation indicated a statistically significant ( P = 0.0003) positive correlation (0.31; 95% confidence interval 0.14-0.46) between the CSU-FAPS and the CMPS-Feline. Conclusions and relevance The CSU-FAPS showed moderate-to-good inter-rater reliability when used by veterinarians to assess pain level or need to reassess analgesic plan after ovariohysterectomy in cats. The validity fell short of current guidelines for correlation coefficients and further refinement and testing are warranted to improve its performance.

Development and validation of an ultra high performance liquid chromatography electrospray ionization tandem mass spectrometry method for the simultaneous determination of selected flavonoids in Ginkgo biloba.

PubMed

Pandey, Renu; Chandra, Preeti; Arya, Kamal Ram; Kumar, Brijesh

2014-12-01

A rapid and sensitive ultra high performance liquid chromatography electrospray ionization tandem mass spectrometry method was developed and validated for the simultaneous determination of 13 flavonoids in leaf, stem, and fruit extracts of male and female trees of Ginkgo biloba to investigate gender- and age-related variations of flavonoids content. Chromatographic separation was accomplished on an Acquity UPLC BEH C18 column (50 mm × 2.1 mm id, 1.7 μm) in 5 min. Quantitation was performed using negative electrospray ionization mass spectrometry in multiple reaction monitoring mode. The calibration curves of all analytes showed a good linear relationship (r(2) ≥ 0.9977) over the concentration range of 1-1000 ng/mL. The precision evaluated by an intra- and interday study showed RSD ≤ 1.98% and good accuracy with overall recovery in the range from 97.90 to 101.09% (RSD ≤ 1.67%) for all analytes. The method sensitivity expressed as the limit of quantitation was typically 0.25-3.57 ng/mL. The results showed that the total content of 13 flavonoids was higher in the leaf extract of an old male Ginkgo tree compared to young female Ginkgo trees. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Poly(vinyl Alcohol) Borate Gel Polymer Electrolytes Prepared by Electrodeposition and Their Application in Electrochemical Supercapacitors.

PubMed

Jiang, Mengjin; Zhu, Jiadeng; Chen, Chen; Lu, Yao; Ge, Yeqian; Zhang, Xiangwu

2016-02-10

Gel polymer electrolytes (GPEs) have been studied for preparing flexible and compact electrochemical energy storage devices. However, the preparation and use of GPEs are complex, and most GPEs prepared through traditional methods do not have good wettability with the electrodes, which retard them from achieving their performance potential. In this study, these problems are addressed by conceiving and implementing a simple, but effective, method of electrodepositing poly(vinyl alcohol) potassium borate (PVAPB) GPEs directly onto the surfaces of active carbon electrodes for electrochemical supercapacitors. PVAPB GPEs serve as both the electrolyte and the separator in the assembled supercapacitors, and their scale and shape are determined solely by the geometry of the electrodes. PVAPB GPEs have good bonding to the active electrode materials, leading to excellent and stable electrochemical performance of the supercapacitors. The electrochemical performance of PVAPB GPEs and supercapacitors can be manipulated simply by adjusting the concentration of KCl salt used during the electrodeposition process. With a 0.9 M KCl concentration, the as-prepared supercapacitors deliver a specific capacitance of 65.9 F g(-1) at a current density of 0.1 A g(-1) and retain more than 95% capacitance after 2000 charge/discharge cycles at a current density of 1 A g(-1). These supercapacitors also exhibit intelligent high voltage self-protection function due to the electrolysis-induced cross-linking effect of PVAPB GPEs.

Numerical simulation of damage evolution for ductile materials and mechanical properties study

NASA Astrophysics Data System (ADS)

El Amri, A.; Hanafi, I.; Haddou, M. E. Y.; Khamlichi, A.

2015-12-01

This paper presents results of a numerical modelling of ductile fracture and failure of elements made of 5182H111 aluminium alloys subjected to dynamic traction. The analysis was performed using Johnson-Cook model based on ABAQUS software. The modelling difficulty related to prediction of ductile fracture mainly arises because there is a tremendous span of length scales from the structural problem to the micro-mechanics problem governing the material separation process. This study has been used the experimental results to calibrate a simple crack propagation criteria for shell elements of which one has often been used in practical analyses. The performance of the proposed model is in general good and it is believed that the presented results and experimental-numerical calibration procedure can be of use in practical finite-element simulations.

Determination of Betaine in Forsythia Suspensa by High Performance Capillary Electrophoresis

NASA Astrophysics Data System (ADS)

Liu, Haixing; Dong, Guoliang; Wang, Lintong

2017-12-01

This paper presents the determination of betaine content of Forsythia suspensa by high performance capillary electrophoresis (HPCE) method. The borax solution was chosen as buffer solution, and its concentration was 40 mmol with capillary column (75μm×52/60cm) at a constant voltage of 20kV and injecting pressure time of 10s at 20°C. Linearity was kept in the concent ration range of 0.0113-1.45mg·ml-1 of betaine with correlation coefficient of 0.999. The recovery was in the range of 97%-117% (n=5), The content of betaine was 281.5 mg·g-1and RSD value of 9.6% (n=6) in Forsythia suspensa. This method has the advantage of rapid, accurate and good repeatability in separation and determination of betaine in Forsythia suspensa.

Ultra high performance liquid chromatography with ion-trap TOF-MS for the fast characterization of flavonoids in Citrus bergamia juice.

PubMed

Sommella, Eduardo; Pepe, Giacomo; Pagano, Francesco; Tenore, Gian Carlo; Dugo, Paola; Manfra, Michele; Campiglia, Pietro

2013-10-01

We have developed a fast ultra HPLC with ion-trap TOF-MS method for the analysis of flavonoids in Citrus bergamia juice. With respect to the typical methods for the analysis of these matrices based on conventional HPLC techniques, a tenfold faster separation was attained. The use of a core-shell particle column ensured high resolution within the fast analysis time of only 5 min. Unambiguous determination of flavonoid identity was obtained by the employment of a hybrid ion-trap TOF mass spectrometer with high mass accuracy (average error 1.69 ppm). The system showed good retention time and peak area repeatability, with maximum RSD% values of 0.36 and 3.86, respectively, as well as good linearity (R(2) ≥ 0.99). Our results show that ultra HPLC can be a useful tool for ultra fast qualitative/quantitative analysis of flavonoid compounds in citrus fruit juices. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Self-assembled highly ordered ethane-bridged periodic mesoporous organosilica and its application in HPLC.

PubMed

Huang, Lili; Lu, Juan; Di, Bin; Feng, Fang; Su, Mengxiang; Yan, Fang

2011-09-01

Monodisperse spherical periodic mesoporous organosilicas (PMOs) with ethane integrated in the framework were synthesized and their application as stationary phase for chromatographic separation is demonstrated. The ethane-PMOs were prepared by condensation of 1,2-bis(triethoxysilyl)ethane (BTSE) in basic condition using octadecyltrimethylammonium chloride (C(18)TMACl) as template and ethanol as co-solvent. The morphology and mesoporous structure of ethane-PMOs were controlled under different concentrations of sodium hydroxide (NaOH) and EtOH. The results of scanning electron microscopy (SEM), transmission electron microscopy (TEM), powder X-ray diffraction (XRD), nitrogen sorption measurement, Fourier transform infrared spectroscopy (FT-IR) and elemental analysis showed that ethane-PMOs have spherical morphology, uniform particle distribution, highly ordered pore structure, high surface area and narrow pore-size distribution. The column packed with these materials exhibits good permeability, high chemical stability and good selectivity of mixtures of aromatic hydrocarbons in normal phase high-performance liquid chromatography (HPLC). Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Exploratory tests of two strut fuel injectors for supersonic combustion

NASA Technical Reports Server (NTRS)

Anderson, G. Y.; Gooderum, P. B.

1974-01-01

Results of supersonic mixing and combustion tests performed with two simple strut injector configurations, one with parallel injectors and one with perpendicular injectors, are presented and analyzed. Good agreement is obtained between static pressure measured on the duct wall downstream of the strut injectors and distributions obtained from one-dimensional calculations. Measured duct heat load agrees with results of the one-dimensional calculations for moderate amounts of reaction, but is underestimated when large separated regions occur near the injection location. For the parallel injection strut, good agreement is obtained between the shape of the injected fuel distribution inferred from gas sample measurements at the duct exit and the distribution calculated with a multiple-jet mixing theory. The overall fraction of injected fuel reacted in the multiple-jet calculation closely matches the amount of fuel reaction necessary to match static pressure with the one-dimensional calculation. Gas sample measurements with the perpendicular injection strut also give results consistent with the amount of fuel reaction in the one-dimensional calculation.

Imagery analysis and the need for standards

NASA Astrophysics Data System (ADS)

Grant, Barbara G.

2014-09-01

While efforts within the optics community focus on the development of high-quality systems and data products, comparatively little attention is paid to their use. Our standards for verification and validation are high; but in some user domains, standards are either lax or do not exist at all. In forensic imagery analysis, for example, standards exist to judge image quality, but do not exist to judge the quality of an analysis. In litigation, a high quality analysis is by default the one performed by the victorious attorney's expert. This paper argues for the need to extend quality standards into the domain of imagery analysis, which is expected to increase in national visibility and significance with the increasing deployment of unmanned aerial vehicle—UAV, or "drone"—sensors in the continental U. S.. It argues that like a good radiometric calibration, made as independent of the calibrated instrument as possible, a good analysis should be subject to standards the most basic of which is the separation of issues of scientific fact from analysis results.

Multiple-component Decomposition from Millimeter Single-channel Data

NASA Astrophysics Data System (ADS)

Rodríguez-Montoya, Iván; Sánchez-Argüelles, David; Aretxaga, Itziar; Bertone, Emanuele; Chávez-Dagostino, Miguel; Hughes, David H.; Montaña, Alfredo; Wilson, Grant W.; Zeballos, Milagros

2018-03-01

We present an implementation of a blind source separation algorithm to remove foregrounds off millimeter surveys made by single-channel instruments. In order to make possible such a decomposition over single-wavelength data, we generate levels of artificial redundancy, then perform a blind decomposition, calibrate the resulting maps, and lastly measure physical information. We simulate the reduction pipeline using mock data: atmospheric fluctuations, extended astrophysical foregrounds, and point-like sources, but we apply the same methodology to the Aztronomical Thermal Emission Camera/ASTE survey of the Great Observatories Origins Deep Survey–South (GOODS-S). In both applications, our technique robustly decomposes redundant maps into their underlying components, reducing flux bias, improving signal-to-noise ratio, and minimizing information loss. In particular, GOODS-S is decomposed into four independent physical components: one of them is the already-known map of point sources, two are atmospheric and systematic foregrounds, and the fourth component is an extended emission that can be interpreted as the confusion background of faint sources.

Composite separators and redox flow batteries based on porous separators

DOEpatents

Li, Bin; Wei, Xiaoliang; Luo, Qingtao; Nie, Zimin; Wang, Wei; Sprenkle, Vincent L.

2016-01-12

Composite separators having a porous structure and including acid-stable, hydrophilic, inorganic particles enmeshed in a substantially fully fluorinated polyolefin matrix can be utilized in a number of applications. The inorganic particles can provide hydrophilic characteristics. The pores of the separator result in good selectivity and electrical conductivity. The fluorinated polymeric backbone can result in high chemical stability. Accordingly, one application of the composite separators is in redox flow batteries as low cost membranes. In such applications, the composite separator can also enable additional property-enhancing features compared to ion-exchange membranes. For example, simple capacity control can be achieved through hydraulic pressure by balancing the volumes of electrolyte on each side of the separator. While a porous separator can also allow for volume and pressure regulation, in RFBs that utilize corrosive and/or oxidizing compounds, the composite separators described herein are preferable for their robustness in the presence of such compounds.

Executive brain functions after exposure to nocturnal traffic noise: effects of task difficulty and sleep quality.

PubMed

Schapkin, Sergei A; Falkenstein, Michael; Marks, Anke; Griefahn, Barbara

2006-04-01

The after-effects of nocturnal traffic noise on cognitive performance and inhibitory brain activity were investigated. Twenty participants (18-30 years) performed an easy and a difficult visual Go/Nogo task with simultaneous EEG recording after a quiet night and then during three nights when aircraft noise was presented with equivalent noise levels of 39, 44, and 50 dBA, respectively, between 11 p.m. to 7 a.m. Based on subjective sleep quality rating, participants were separated into "good" versus "bad" sleepers. The performance and inhibition-related components (N2, P3) of event-related potentials were analysed. The N2 and P3 amplitudes were smaller and latencies were prolonged in the difficult than in the easy task. This effect was more pronounced for Nogo than for Go trials. The Nogo-P3 amplitude was smaller in Noise than in "Quiet" conditions in the difficult task only. In the difficult task, the Nogo-P3 latency was prolonged in bad sleepers than in good sleepers. The Nogo-P3 amplitude was reduced in Noise as compared to "Quiet" conditions in bad sleepers only. Sleep quality in bad sleepers worsened steadily with increasing noise levels. No effects of noise or subjective sleep quality on performance were found. Inhibitory processes appear to be selectively impaired after nocturnal noise exposure. The task difficulty and perceived sleep quality are important factors modulating noise effects. The results suggest that nocturnal traffic noise increase physiological costs for inhibitory functioning on the day even if no overt performance decrement is observed.

Performance of the ASAS classification criteria for axial and peripheral spondyloarthritis: a systematic literature review and meta-analysis.

PubMed

Sepriano, Alexandre; Rubio, Roxana; Ramiro, Sofia; Landewé, Robert; van der Heijde, Désirée

2017-05-01

To summarise the evidence on the performance of the Assessment of SpondyloArthritis international Society (ASAS) classification criteria for axial spondyloarthritis (axSpA) (also imaging and clinical arm separately), peripheral (p)SpA and the entire set, when tested against the rheumatologist's diagnosis ('reference standard'). A systematic literature review was performed to identify eligible studies. Raw data on SpA diagnosis and classification were extracted or, if necessary, obtained from the authors of the selected publications. A meta-analysis was performed to obtain pooled estimates for sensitivity, specificity, positive and negative likelihood ratios, by fitting random effects models. Nine papers fulfilled the inclusion criteria (N=5739 patients). The entire set of the ASAS SpA criteria yielded a high pooled sensitivity (73%) and specificity (88%). Similarly, good results were found for the axSpA criteria (sensitivity: 82%; specificity: 88%). Splitting the axSpA criteria in 'imaging arm only' and 'clinical arm only' resulted in much lower sensitivity (30% and 23% respectively), but very high specificity was retained (97% and 94% respectively). The pSpA criteria were less often tested than the axSpA criteria and showed a similarly high pooled specificity (87%) but lower sensitivity (63%). Accumulated evidence from studies with more than 5500 patients confirms the good performance of the various ASAS SpA criteria as tested against the rheumatologist's diagnosis. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

Psychometric analysis of an eating behaviour questionnaire for an overweight and obese Chinese population in Singapore.

PubMed

Chong, Mary Foong-Fong; Ayob, M Na'im M; Chong, Kok Joon; Tai, E-Shyong; Khoo, Chin Meng; Leow, Melvin Khee-Shing; Lee, Yung Seng; Tham, Kwang Wei; Venkataraman, Kavita; Meaney, Michael J; Wee, Hwee Lin; Khoo, Eric Yin-Hao

2016-06-01

Previous studies reveal that the Three-Factor Eating Questionnaire (TFEQ), which assesses eating behaviour, performs differently across population groups and cultures. We aimed to identify the factor structure that is most appropriate to capture eating behaviour in an overweight and obese Chinese population in Singapore. TFEQ-51 was administered to 444 Chinese subjects pooled from four separate studies and scored according to various alternative versions of the TFEQ. Confirmatory factor analyses and goodness of fit indices were used to determine the most appropriate factor structure. Known-group validity analyses were conducted. Niemeier's Disinhibition Factors and the TFEQ-R18 factor structures were found to be the most applicable in our population based on goodness of fit indices, with a x(2)/df ratio of <3, RMSEA of ≤ 0.6 and a CFI value of >0.9 for both. Only two of three factors (Emotional Eating and Uncontrolled Eating) of the TFEQ-R18 showed good internal consistency, while none of Niemeier's Disinhibition Factors showed good internal consistency. Known-group validity showed that Emotional Eating and Internal Disinhibition were significantly associated with higher BMI. We found that the TFEQ-R18 factor structure is the most appropriate and practical for use in measuring eating behaviour in an overweight and obese Chinese population in Singapore. Copyright © 2016 Elsevier Ltd. All rights reserved.

Conformational effect of dicyclo-hexano-18-crown-6 on isotopic fractionation of zinc: DFT approach

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

Boda, A.; Singha Deb, A. K.; Ali, Sk. M.

2014-04-24

Generalized gradient approximated BP86 density functional employing triple zeta valence plus polarization (TZVP) basis set has been used to compute the reduced partition function ratio and isotopic separation factor for zinc isotopes. The isotopic separation factor was found to be in good agreement with the experimental results. The isotopic separation factor was found to depend on the conformation of the crown ether ligand. The trans-trans conformation shows the highest fractionation compared to cis-cis conformer. The present theoretical results can thus be used to plan the isotope separation experiments.

Linear solvation energy relationships in normal phase chromatography based on gradient separations.

PubMed

Wu, Di; Lucy, Charles A

2017-09-22

Coupling the modified Soczewiñski model and one gradient run, a gradient method was developed to build a linear solvation energy relationship (LSER) for normal phase chromatography. The gradient method was tested on dinitroanilinopropyl (DNAP) and silica columns with hexane/dichloromethane (DCM) mobile phases. LSER models built based on the gradient separation agree with those derived from a series of isocratic separations. Both models have similar LSER coefficients and comparable goodness of fit, but the LSER model based on gradient separation required fewer trial and error experiments. Copyright © 2017 Elsevier B.V. All rights reserved.

Impact of solvent conditions on separation and detection of basic drugs by micro liquid chromatography-mass spectrometry under overloading conditions.

PubMed

Schubert, Birthe; Oberacher, Herbert

2011-06-03

In this study the impact of solvent conditions on the performance of μLC/MS for the analysis of basic drugs was investigated. Our aim was to find experimental conditions that enable high-performance chromatographic separation particularly at overloading conditions paired with a minimal loss of mass spectrometric detection sensitivity. A focus was put on the evaluation of the usability of different kinds of acidic modifiers (acetic acid (HOAc), formic acid (FA), methansulfonic acid (CH₃SO₃H), trifluoroacetic acid (TFA), pentafluoropropionic acid (PFPA), and heptafluorobutyric acid (HFBA)). The test mixture consisted of eleven compounds (bunitrolol, caffeine, cocaine, codeine, diazepam, doxepin, haloperidol, 3,4-methylendioxyamphetamine, morphine, nicotine, and zolpidem). Best chromatographic performance was obtained with the perfluorinated acids. Particularly, 0.010-0.050% HFBA (v/v) was found to represent a good compromise in terms of chromatographic performance and mass spectrometric detection sensitivity. Compared to HOAc, on average a 50% reduction of the peak widths was observed. The use of HFBA was particularly advantageous for polar compounds such as nicotine; only with such a hydrophobic ion-pairing reagent chromatographic retention of nicotine was observed. Best mass spectrometric performance was obtained with HOAc and FA. Loss of detection sensitivity induced by HFBA, however, was moderate and ranged from 0 to 40%, which clearly demonstrates that improved chromatographic performance is able to compensate to a large extent the negative effect of reduced ionization efficiency on detection sensitivity. Applications of μLC/MS for the qualitative and quantitative analysis of clinical and forensic toxicological samples are presented. Copyright © 2011 Elsevier B.V. All rights reserved.

The effect of gypsum products and separating materials on the typography of denture base materials.

PubMed

Firtell, D N; Walsh, J F; Elahi, J M

1980-09-01

The typography of polymethyl methacrylate processed against various gypsum products coated with various separating materials was studied under an SEM. Tinfoil and two commercial tin foil substitutes were used as separating material during processing, and the surfaces of the resulting acrylic resin forms were studied for topographical differences. Tinfoil and alpha 2 hemihydrates produced the smoothest surfaces. As a practical solution, a good quality tinfoil substitute and alpha 1 hemihydrate could be used when processing polymethyl methacrylate resin.

Here Are the Traits that Separate the Boss Who Walks on Water . . . from the Boss Who's All Wet.

ERIC Educational Resources Information Center

Ficklen, Ellen

1984-01-01

Discusses characteristics of good and bad bosses in school systems. Good bosses create a team spirit, show concern, fairness, and trust for their employees, and have demanding but clear expectations, though they allow for mistakes. Bad bosses are self-centered and either neglect or tyrannize their employees. (TE)

29 CFR 779.348 - Goods must be made at the establishment which sells them.

Code of Federal Regulations, 2014 CFR

2014-07-01

... not be exempt. The latter is a manufacturing establishment. For example, a candy kitchen manufacturing candy for sale at separate retail outlets is a manufacturing establishment and not a retail... goods for sale to customers who will go to other places to buy them. Thus an establishment that makes or...

29 CFR 779.348 - Goods must be made at the establishment which sells them.

Code of Federal Regulations, 2013 CFR

2013-07-01

... not be exempt. The latter is a manufacturing establishment. For example, a candy kitchen manufacturing candy for sale at separate retail outlets is a manufacturing establishment and not a retail... goods for sale to customers who will go to other places to buy them. Thus an establishment that makes or...

29 CFR 779.348 - Goods must be made at the establishment which sells them.

Code of Federal Regulations, 2012 CFR

2012-07-01

... not be exempt. The latter is a manufacturing establishment. For example, a candy kitchen manufacturing candy for sale at separate retail outlets is a manufacturing establishment and not a retail... goods for sale to customers who will go to other places to buy them. Thus an establishment that makes or...

Separating the Boys from the Girls

ERIC Educational Resources Information Center

Patterson, Gregory A.

2012-01-01

Students at Claremont Academy in Chicago and their scores have become a proof point in a broadening argument between adults and institutions over whether single-sex education does more good than harm, or whether it does any good at all. The battle pits the American Civil Liberties Union and women's groups against some who have been frequent allies…

Evaluation of interobserver variability and diagnostic performance of developed MRI-based radiological scoring system for invasive placenta previa.

PubMed

Ueno, Yoshiko; Maeda, Tetsuo; Tanaka, Utaru; Tanimura, Kenji; Kitajima, Kazuhiro; Suenaga, Yuko; Takahashi, Satoru; Yamada, Hideto; Sugimura, Kazuro

2016-09-01

To evaluate the interobserver variability and diagnostic performance of a developed magnetic resonance imaging (MRI)-based scoring system for invasive placenta previa. Prenatal MR images of 70 women were retrospectively evaluated, 18 of whom were diagnosed with invasive placenta. The six MR features (dark band on T2 -weighted images, intraplacental abnormal vascularity, placental bulge, heterogeneous placenta, myometrial thinning, and placental protrusion sign) were scored on 5-point Likert scale separately, and the cumulative radiological score (CRS) was defined as the sum of each score. Two more experienced radiologists (readers A and B) and two less experienced residents (readers C and D) calculated the CRS. Interobserver variability was assessed by measuring the intraclass correlation coefficient. Diagnostic performance was evaluated by means of receiver operating characteristic (ROC) analysis. Interobserver variability for CRS was excellent for the more experienced radiologists (0.85), and good for all readers (0.72) and the less experienced residents (0.66). The area under the ROC curve (Az) and accuracy (Acc) for CRS were significantly higher or equivalent to those of other MR features for all readers (Az and Acc for reader A; CRS, 0.92, 91.4%; intraplacental T2 dark band, 0.83, P = 0.009, 81.4%, P = 0.03; intraplacental abnormal vascularity, 0.9, P = 0.3, 90.0%, P = 1.00; placental bulge, 0.81, P = 0.0008, 80.0%, P = 0.02; heterogeneous placenta, 0.85, P = 0.11, 74.3%, P = 0.002; myometrial thinning, 0.84, P = 0.06, 60.0%, P < 0.0001; placental protrusion sign, 0.81, P = 0.01, 81.4%, P = 0.26). This developed MRI-based scoring system demonstrated excellent or good interobserver variability, and good diagnostic performance for invasive placenta previa. J. Magn. Reson. Imaging 2016;44:573-583. © 2016 International Society for Magnetic Resonance in Medicine.

Vortex-assisted emulsification semimicroextraction for the analytical control of restricted ingredients in cosmetic products: determination of bronopol by liquid chromatography.

PubMed

Miralles, Pablo; Bellver, Raquel; Chisvert, Alberto; Salvador, Amparo

2016-03-01

Vortex-assisted emulsification semimicroextraction is proposed as a one-step solution-extraction procedure for sample preparation in cosmetic products. The procedure allows rapid preparation based on dispersion of the sample in a mixture of 1 mL of n-hexane and 0.5 mL of ethanol, followed by the addition of 0.5 mL of water and centrifugation to obtain two separated phases. This procedure provides good sample clean-up with minimum dilution and is very useful for the determination of ingredients with restricted concentrations, such as bronopol. The procedure was applied to the determination of bronopol by liquid chromatography with UV detection. The best chromatographic separation was obtained by using a C18 column set at 40 °C and performing a stepwise elution with a mixture of ethanol/aqueous 1 % acetic acid solution as mobile phase pumped at 0.5 mL min(-1). The detection wavelength was set at 250 nm and the total run time required was 12 min. The method was successfully applied to 18 commercial cosmetic samples including creams, shampoos, and bath gels. Good recoveries and repeatability were obtained, with a limit of detection of 0.9 μg mL(-1), which makes the method suitable for the analytical control of cosmetic products. Moreover, it could be considered environmentally friendly, because water, ethanol, and only a low volume of n-hexane are used as solvents.

Temperature Compensated Sapphire Resonator for Ultrastable Oscillator Operating at Temperatures Near 77 Deg Kelvin

NASA Technical Reports Server (NTRS)

Dick, G. John (Inventor); Santiago, David G. (Inventor)

1999-01-01

A sapphire resonator for an ultrastable oscillator capable of substantial performance improvements over the best available crystal quartz oscillators in a compact cryogenic package is based on a compensation mechanism enabled by the difference between copper and sapphire thermal expansion coefficients for so tuning the resonator as to cancel the temperature variation of the sapphire's dielectric constant. The sapphire resonator consists of a sapphire ring separated into two parts with webs on the outer end of each to form two re-entrant parts which are separated by a copper post. The re-entrant parts are bonded to the post by indium solder for good thermal conductivity between parts of that subassembly which is supported on the base plate of a closed copper cylinder (rf shielding casing) by a thin stainless steel cylinder. A unit for temperature control is placed in the stainless steel cylinder and is connected to the subassembly of re-entrant parts and copper post by a layer of indium for good thermal conduction. In normal use, the rf shielding casing is placed in a vacuum tank which is in turn placed in a thermos flask of liquid nitrogen. The temperature regulator is controlled from outside the thermos flask to a temperature in a range of about 40K to 150K, such as 87K for the WGH-811, mode of resonance in response to microwave energy inserted into the rf shielding casing through a port from an outside source.

A microfabricated low cost enzyme-free glucose fuel cell for powering low-power implantable devices

NASA Astrophysics Data System (ADS)

Oncescu, Vlad; Erickson, David

In the past decade the scientific community has showed considerable interest in the development of implantable medical devices such as muscle stimulators, neuroprosthetic devices, and biosensors. Those devices have low power requirements and can potentially be operated through fuel cells using reactants present in the body such as glucose and oxygen instead of non-rechargeable lithium batteries. In this paper, we present a thin, enzyme-free fuel cell with high current density and good stability at a current density of 10 μA cm -2. A non-enzymatic approach is preferred because of higher long term stability. The fuel cell uses a stacked electrode design in order to achieve glucose and oxygen separation. An important characteristic of the fuel cell is that it has no membrane separating the electrodes, which results in low ohmic losses and small fuel cell volume. In addition, it uses a porous carbon paper support for the anodic catalyst layer which reduces the amount of platinum or other noble metal catalysts required for fabricating high surface area electrodes with good reactivity. The peak power output of the fuel cell is approximately 2 μW cm -2 and has a sustainable power density of 1.5 μW cm -2 at 10 μA cm -2. An analysis on the effects of electrode thickness and inter electrode gap on the maximum power output of the fuel cell is also performed.

Disposable pen-shaped capillary gel electrophoresis cartridge for fluorescence detection of bio-molecules

NASA Astrophysics Data System (ADS)

Amirkhanian, Varoujan; Tsai, Shou-Kuan

2014-03-01

We introduce a novel and cost-effective capillary gel electrophoresis (CGE) system utilizing disposable pen-shaped gelcartridges for highly efficient, high speed, high throughput fluorescence detection of bio-molecules. The CGE system has been integrated with dual excitation and emission optical-fibers with micro-ball end design for fluorescence detection of bio-molecules separated and detected in a disposable pen-shaped capillary gel electrophoresis cartridge. The high-performance capillary gel electrophoresis (CGE) analyzer has been optimized for glycoprotein analysis type applications. Using commercially available labeling agent such as ANTS (8-aminonapthalene-1,3,6- trisulfonate) as an indicator, the capillary gel electrophoresis-based glycan analyzer provides high detection sensitivity and high resolving power in 2-5 minutes of separations. The system can hold total of 96 samples, which can be automatically analyzed within 4-5 hours. This affordable fiber optic based fluorescence detection system provides fast run times (4 minutes vs. 20 minutes with other CE systems), provides improved peak resolution, good linear dynamic range and reproducible migration times, that can be used in laboratories for high speed glycan (N-glycan) profiling applications. The CGE-based glycan analyzer will significantly increase the pace at which glycoprotein research is performed in the labs, saving hours of preparation time and assuring accurate, consistent and economical results.

Simultaneous quantification of major flavonoids in "Bawanghua", the edible flower of Hylocereus undatus using pressurised liquid extraction and high performance liquid chromatography.

PubMed

Yi, Yan; Zhang, Qing-Wen; Li, Song-Lin; Wang, Ying; Ye, Wen-Cai; Zhao, Jing; Wang, Yi-Tao

2012-11-15

A pressurised liquid extraction (PLE) and high performance liquid chromatography (HPLC) method was developed for simultaneous quantification of six major flavonoids in edible flower of Hylocereus undatus. In order to achieve the baseline separation of two pairs of isomers, the HPLC conditions were optimised with different kind of reversed phase columns and mobile phase gradient programs. In addition, the solvent concentration, extraction temperature, extraction time and flush cycle for PLE were also optimised. Zorbax SB-C8 (100×2.1 mm, 1.8 μm) column was chosen with acetonitrile and water containing 0.1% trifluoroacetic acid as mobile phase, the six analytes were eluted with baseline separation. The calibration curves showed good linearity (r(2)>0.9994) with LODs and LOQs less than 0.90 and 3.60 ng respectively. The RSDs for intra- and inter-day repeatability was not more than 1.09% and 1.79% respectively. The overall recovery of the assay was 96.9-105.2%. The sample was stable for at least 12 h. The newly established method was successfully applied to quantify six flavonoids in different parts of "Bawanghua", and the commercial samples from different locations. Copyright © 2012 Elsevier Ltd. All rights reserved.

Micro supercapacitors based on a 3D structure with symmetric graphene or activated carbon electrodes

NASA Astrophysics Data System (ADS)

Li, Siwei; Wang, Xiaohong; Xing, Hexin; Shen, Caiwei

2013-11-01

This paper presents three-dimensional (3D) micro supercapacitors with thick interdigital electrodes supported and separated by SU-8. Nanoporous carbon materials including graphene and activated carbon (AC) are used as active materials in self-supporting composites to build the electrodes. The SU-8 separators provide mechanical support for thick electrodes and allow a considerable amount of material to be loaded in a limited footprint area. The prototypes have been accomplished by a simple microelectromechanical systems (MEMS) fabrication process and sealed by polydimethylsiloxane (PDMS) caps with ionic liquid electrolytes injected into the electrode area. Electrochemical tests demonstrate that the graphene-based prototype with 100 µm thick electrodes shows good power performance and provides a considerable specific capacitance of about 60 mF cm-2. Two AC-based prototypes show larger capacitance of 160 mF cm-2 and 311 mF cm-2 with 100 µm and 200 µm thick electrodes respectively, because of higher volume density of the material. The results demonstrate that both thick 3D electrode structure and volume capacitance of the electrode material are key factors for high-performance micro supercapacitors, which can be potentially used in specific applications such as power suppliers and storage components for harvesters.

Interfacial damage identification of steel and concrete composite beams based on piezoceramic wave method.

PubMed

Yan, Shi; Dai, Yong; Zhao, Putian; Liu, Weiling

2018-01-01

Steel-concrete composite structures are playing an increasingly important role in economic construction because of a series of advantages of great stiffness, good seismic performance, steel material saving, cost efficiency, convenient construction, etc. However, in service process, due to the long-term effects of environmental impacts and dynamic loading, interfaces of a composite structure might generate debonding cracks, relative slips or separations, and so on, lowering the composite effect of the composite structure. In this paper, the piezoceramics (PZT) are used as transducers to perform experiments on interface debonding slips and separations of composite beams, respectively, aimed at proposing an interface damage identification model and a relevant damage detection innovation method based on PZT wave technology. One part of various PZT patches was embedded in concrete as "smart aggregates," and another part of the PZT patches was pasted on the surface of the steel beam flange, forming a sensor array. A push-out test for four specimens was carried out and experimental results showed that, under the action of the external loading, the received signal amplitudes will increasingly decrease with increase of debonding slips along the interface. The proposed signal energy-based interface damage detection algorithm is highly efficient in surface state evaluations of composite beams.

Applications of hierarchically structured porous materials from energy storage and conversion, catalysis, photocatalysis, adsorption, separation, and sensing to biomedicine.

PubMed

Sun, Ming-Hui; Huang, Shao-Zhuan; Chen, Li-Hua; Li, Yu; Yang, Xiao-Yu; Yuan, Zhong-Yong; Su, Bao-Lian

2016-06-13

Over the last decade, significant effort has been devoted to the applications of hierarchically structured porous materials owing to their outstanding properties such as high surface area, excellent accessibility to active sites, and enhanced mass transport and diffusion. The hierarchy of porosity, structural, morphological and component levels in these materials is key for their high performance in all kinds of applications. The introduction of hierarchical porosity into materials has led to a significant improvement in the performance of materials. Herein, recent progress in the applications of hierarchically structured porous materials from energy conversion and storage, catalysis, photocatalysis, adsorption, separation, and sensing to biomedicine is reviewed. Their potential future applications are also highlighted. We particularly dwell on the relationship between hierarchically porous structures and properties, with examples of each type of hierarchically structured porous material according to its chemical composition and physical characteristics. The present review aims to open up a new avenue to guide the readers to quickly obtain in-depth knowledge of applications of hierarchically porous materials and to have a good idea about selecting and designing suitable hierarchically porous materials for a specific application. In addition to focusing on the applications of hierarchically porous materials, this comprehensive review could stimulate researchers to synthesize new advanced hierarchically porous solids.

Performance optimization in electric field gradient focusing.

PubMed

Sun, Xuefei; Farnsworth, Paul B; Tolley, H Dennis; Warnick, Karl F; Woolley, Adam T; Lee, Milton L

2009-01-02

Electric field gradient focusing (EFGF) is a technique used to simultaneously separate and concentrate biomacromolecules, such as proteins, based on the opposing forces of an electric field gradient and a hydrodynamic flow. Recently, we reported EFGF devices fabricated completely from copolymers functionalized with poly(ethylene glycol), which display excellent resistance to protein adsorption. However, the previous devices did not provide the predicted linear electric field gradient and stable current. To improve performance, Tris-HCl buffer that was previously doped in the hydrogel was replaced with a phosphate buffer containing a salt (i.e., potassium chloride, KCl) with high mobility ions. The new devices exhibited stable current, good reproducibility, and a linear electric field distribution in agreement with the shaped gradient region design due to improved ion transport in the hydrogel. The field gradient was calculated based on theory to be approximately 5.76 V/cm(2) for R-phycoerythrin when the applied voltage was 500 V. The effect of EFGF separation channel dimensions was also investigated; a narrower focused band was achieved in a smaller diameter channel. The relationship between the bandwidth and channel diameter is consistent with theory. Three model proteins were resolved in an EFGF channel of this design. The improved device demonstrated 14,000-fold concentration of a protein sample (from 2 ng/mL to 27 microg/mL).

Critical assessment of three high performance liquid chromatography analytical methods for food carotenoid quantification.

PubMed

Dias, M Graça; Oliveira, Luísa; Camões, M Filomena G F C; Nunes, Baltazar; Versloot, Pieter; Hulshof, Paul J M

2010-05-21

Three sets of extraction/saponification/HPLC conditions for food carotenoid quantification were technically and economically compared. Samples were analysed for carotenoids alpha-carotene, beta-carotene, beta-cryptoxanthin, lutein, lycopene, and zeaxanthin. All methods demonstrated good performance in the analysis of a composite food standard reference material for the analytes they are applicable to. Methods using two serial connected C(18) columns and a mobile phase based on acetonitrile, achieved a better carotenoid separation than the method using a mobile phase based on methanol and one C(18)-column. Carotenoids from leafy green vegetable matrices appeared to be better extracted with a mixture of methanol and tetrahydrofuran than with tetrahydrofuran alone. Costs of carotenoid determination in foods were lower for the method with mobile phase based on methanol. However for some food matrices and in the case of E-Z isomer separations, this was not technically satisfactory. Food extraction with methanol and tetrahydrofuran with direct evaporation of these solvents, and saponification (when needed) using pyrogallol as antioxidant, combined with a HPLC system using a slight gradient mobile phase based on acetonitrile and a stationary phase composed by two serial connected C(18) columns was the most technically and economically favourable method. 2010. Published by Elsevier B.V.

High performance liquid chromatography with photo diode array for separation and analysis of naproxen and esomeprazole in presence of their chiral impurities: Enantiomeric purity determination in tablets.

PubMed

Ragab, Marwa A A; El-Kimary, Eman I

2017-05-12

A stereoselective high performance liquid chromatographic method with diode array detection (HPLC-DAD) was introduced for S-naproxen and esomeprazole determination in tablets. The separation was achieved on a Kromasil Cellucoat chiral column using a mobile phase consisting of hexane: isopropanol: trifluoroacetic acid (TFA) (90:9.9:0.1 v/v/v). The proposed system was found to be suitable for the enantioseparation of naproxen and omeprazole biologically active isomers. After optimization of the chromatographic conditions, resolution values of 3.84 and 2.17 could be obtained for naproxen and omeprazole isomers, respectively. The method was fully validated for the determination of S-isomers of each drug in their dosage form. Also, the enentiomeric purity was determined in commercial tablet containing S-naproxen and esomeprazole. The enantiomeric purity was calculated for each drug and the chiral impurities (R-isomers) could be determined at 1% level. The method was validated and good results with respect to linearity, precision, accuracy, selectivity and robustness were obtained. The limits of detection (LOD) and quantification (LOQ) were 2.00, 6.50 and 0.10, 0.35μgmL -1 for S-naproxen and esomeprazole, respectively. Copyright © 2017 Elsevier B.V. All rights reserved.

Fabrication of Polyimide Membrane Incorporated with Functional Graphene Oxide for CO2 Separation: The Effects of GO Surface Modification on Membrane Performance.

PubMed

Wang, Ting; Cheng, Cheng; Wu, Li-Guang; Shen, Jiang-Nan; Van der Bruggen, Bart; Chen, Qian; Chen, Di; Dong, Chun-Ying

2017-06-06

Two kinds of isocyanate were used to modify graphene oxide (GO) samples. Then, polyimide (PI) hybrid membranes containing GO and modified GO were prepared by in situ polymerization. The permeation of CO 2 and N 2 was studied using these novel membranes. The morphology experiments showed that the isocyanate groups were successfully grafted on the surface of GO by replacement of the oxygen-containing functional groups. After modification, the surface polarity of the GO increased, and more defect structures were introduced into the GO surface. This resulted in a good distribution of more modified GO samples in the PI polymer matrix. Thus, the PI hybrid membranes incorporated by modified GO samples showed a high gas permeability and ideal selectivity of membranes. In addition, enhancement of the selectivity due to the solubility of CO 2 played a major role in the increase in the separation performance of the hybrid membranes for CO 2 , although the diffusion coefficients for CO 2 also increased. Both the higher condensability and the strong affinity between CO 2 molecules and GO in the polymer matrix caused an enhancement of the solubility selectivity higher than the diffusion selectivity after GO surface modification.

DNS of Low-Pressure Turbine Cascade Flows with Elevated Inflow Turbulence Using a Discontinuous-Galerkin Spectral-Element Method

NASA Technical Reports Server (NTRS)

Garai, Anirban; Diosady, Laslo T.; Murman, Scott M.; Madavan, Nateri K.

2016-01-01

Recent progress towards developing a new computational capability for accurate and efficient high-fidelity direct numerical simulation (DNS) and large-eddy simulation (LES) of turbomachinery is described. This capability is based on an entropy- stable Discontinuous-Galerkin spectral-element approach that extends to arbitrarily high orders of spatial and temporal accuracy, and is implemented in a computationally efficient manner on a modern high performance computer architecture. An inflow turbulence generation procedure based on a linear forcing approach has been incorporated in this framework and DNS conducted to study the effect of inflow turbulence on the suction- side separation bubble in low-pressure turbine (LPT) cascades. The T106 series of airfoil cascades in both lightly (T106A) and highly loaded (T106C) configurations at exit isentropic Reynolds numbers of 60,000 and 80,000, respectively, are considered. The numerical simulations are performed using 8th-order accurate spatial and 4th-order accurate temporal discretization. The changes in separation bubble topology due to elevated inflow turbulence is captured by the present method and the physical mechanisms leading to the changes are explained. The present results are in good agreement with prior numerical simulations but some expected discrepancies with the experimental data for the T106C case are noted and discussed.

An application of the theory of planned behaviour to study the influencing factors of participation in source separation of food waste

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

Karim Ghani, Wan Azlina Wan Ab., E-mail: wanaz@eng.upm.edu.my; Rusli, Iffah Farizan, E-mail: iffahrusli@yahoo.com; Biak, Dayang Radiah Awang, E-mail: dayang@eng.upm.edu.my

Highlights: ► Theory of planned behaviour (TPB) has been conducted to identify the influencing factors for participation in source separation of food waste using self administered questionnaires. ► The findings suggested several implications for the development and implementation of waste separation at home programme. ► The analysis indicates that the attitude towards waste separation is determined as the main predictors where this in turn could be a significant predictor of the repondent’s actual food waste separation behaviour. ► To date, none of similar have been reported elsewhere and this finding will be beneficial to local Authorities as indicator in designingmore » campaigns to promote the use of waste separation programmes to reinforce the positive attitudes. - Abstract: Tremendous increases in biodegradable (food waste) generation significantly impact the local authorities, who are responsible to manage, treat and dispose of this waste. The process of separation of food waste at its generation source is identified as effective means in reducing the amount food waste sent to landfill and can be reused as feedstock to downstream treatment processes namely composting or anaerobic digestion. However, these efforts will only succeed with positive attitudes and highly participations rate by the public towards the scheme. Thus, the social survey (using questionnaires) to analyse public’s view and influencing factors towards participation in source separation of food waste in households based on the theory of planned behaviour technique (TPB) was performed in June and July 2011 among selected staff in Universiti Putra Malaysia, Serdang, Selangor. The survey demonstrates that the public has positive intention in participating provided the opportunities, facilities and knowledge on waste separation at source are adequately prepared by the respective local authorities. Furthermore, good moral values and situational factors such as storage convenience and collection times are also encouraged public’s involvement and consequently, the participations rate. The findings from this study may provide useful indicator to the waste management authorities in Malaysia in identifying mechanisms for future development and implementation of food waste source separation activities in household programmes and communication campaign which advocate the use of these programmes.« less

The effect of bioadhesive on the interfacial compatibility and pervaporation performance of composite membranes by MD and GCMC simulation.

PubMed

Wang, Baohe; Nie, Yan; Ma, Jing

2018-03-01

Combing molecular dynamics (MD) and Grand Canonical Monte Carlo (GCMC) simulation, the effect of bioadhesive transition layer on the interfacial compatibility of the pervaporation composite membranes, and the pervaporation performance toward penetrant molecules were investigated. In our previous experimental study, the structural stability and permeability selectivity of the composite membranes were considerably enhanced by the introduction of bioadhesive carbopol (CP). In the present study, the interfacial compatibility and the interfacial energies between the chitosan (CS) separation layer, CP transition layer and the support layer were investigated, respectively. The mobility of polymer chains, free volume in bulk and interface regions were evaluated by the mean-square displacement (MSD) and free volume voids (FFV) analysis. The diffusion and sorption behavior of water/ethanol molecules in bulk and interface regions were characterized. The simulation results of membrane structure have good consistency, indicating that the introduction of CP transition layer improved the interfacial compatibility and interaction between the separation layer and the support layer. Comparing the bulk region of the separation layer, the mobility and free volume of the polymer chain in the interface region decreased and thus reduced the swelling of CS active layer, revealing the increased diffusion selectivity toward the permeated water and ethanol molecules. The strong hydrogen bonds interaction between the COOH of the CP transition layer and water molecules increased the adsorption of water molecules in the interface region. The simulation results were quite consistent with the experimental results. Copyright © 2018 Elsevier Inc. All rights reserved.

Top-down and middle-down approach by fraction collection enrichment using off-line capillary electrophoresis - mass spectrometry coupling: Application to monoclonal antibody Fc/2 charge variants.

PubMed

Biacchi, Michael; Said, Nassur; Beck, Alain; Leize-Wagner, Emmanuelle; François, Yannis-Nicolas

2017-05-19

The characterization of complex protein mixtures represents one of the biggest challenge in many research fields such as biological or biopharmaceutical sciences. Out of all categories, monoclonal antibodies (mAbs) and related products drawn the most interest due to their strong therapeutic potency and specificity. Because of their intrinsic complexity due to a large number of micro-heterogeneities, there is a crucial need for analytical methods to provide comprehensive in-depth characterization of these proteins. In this work, we developed a methodology using CE-UV/MALDI-MS to perform top-down or middle-down characterization after fraction collection enrichment applied to intact protein and mAbs samples. The performance of the method was evaluated with the rapid separation of three intact protein mixture. Good robustness of CZE separation and quality of MALDI-MS spectra and MALDI-ISD spectra of each protein confirms the usefulness of sample enrichment to obtain adequate quantity of deposed protein for top-down analysis and the proof of principle of the method. In a second step, the method was applied to the middle-down characterization of Fc/2 cetuximab variants. Identification of around 9% sequence coverage of Fc/2 cetuximab fragments allows to conclude on the feasibility of the strategy for middle-down characterization of Fc/2 cetuximab variants using CE-UV/MALDI-MS. Moreover, MALDI-ISD fragmentation of Fc/2 cetuximab variants confirm separation phenomenon based on the formation of Fc/2 dimers with and without C-terminal truncation. Copyright © 2017 Elsevier B.V. All rights reserved.

Comment on 'Modeling of Convective-Stratiform Precipitation Processes: Sensitivity to Partitioning Methods' by Matthias Steiner

NASA Technical Reports Server (NTRS)

Lang, Steve; Tao, W.-K.; Simpson, J.; Ferrier, B.

2003-01-01

Despite the obvious notion that the presence of hail or graupel is a good indication of convection, the model results show this does not provide an objective benchmark partly due to the unrealistic presence of small amounts of hail or graupel throughout the anvil in the model but mainly because of the significant amounts of hail or graupel, especially in the tropical TOGA COARE simulation, in the transition zone. Without use of a "transition" category, it is open to debate as how this region should best be defined, as stratiform or as convective. So, the presence of significant hail or graupel contents in this zone significantly degrades its use an objective benchmark for convection. The separation algorithm comparison was done in the context of a cloud-resolving model. These models are widely used and serve a variety of purposes especially with regard to retrieving information that cannot be directly measured by providing synthetic data sets that are consistent and complete. Separation algorithms are regularly applied in these models. However, as with any modeling system, these types 'of models are constantly being improved to overcome any known deficiencies and make them more accurate representations of observed systems. The presence of hail and graupel in the anvil and the bias towards heavy rainfall rates are two such examples of areas that need improvement. Since, both of these can effect the perceived performance of the separation algorithms, the Lang et al. (2003) study did not want to overstate the relative performance of any specific algorithms.

Does an electronic continuum correction improve effective short-range ion-ion interactions in aqueous solution?

NASA Astrophysics Data System (ADS)

Bruce, Ellen E.; van der Vegt, Nico F. A.

2018-06-01

Non-polarizable force fields for hydrated ions not always accurately describe short-range ion-ion interactions, frequently leading to artificial ion clustering in bulk aqueous solutions. This can be avoided by adjusting the nonbonded anion-cation or cation-water Lennard-Jones parameters. This approach has been successfully applied to different systems, but the parameterization is demanding owing to the necessity of separate investigations of each ion pair. Alternatively, polarization effects may effectively be accounted for using the electronic continuum correction (ECC) of Leontyev et al. [J. Chem. Phys. 119, 8024 (2003)], which involves scaling the ionic charges with the inverse square-root of the water high-frequency dielectric permittivity. ECC has proven to perform well for monovalent salts as well as for divalent salts in water. Its performance, however, for multivalent salts with higher valency remains unexplored. The present work illustrates the applicability of the ECC model to trivalent K3PO4 and divalent K2HPO4 in water. We demonstrate that the ECC models, without additional tuning of force field parameters, provide an accurate description of water-mediated interactions between salt ions. This results in predictions of the osmotic coefficients of aqueous K3PO4 and K2HPO4 solutions in good agreement with experimental data. Analysis of ion pairing thermodynamics in terms of contact ion pair (CIP), solvent-separated ion pair, and double solvent-separated ion pair contributions shows that potassium-phosphate CIP formation is stronger with trivalent than with divalent phosphate ions.

Prospective assessment of interobserver agreement for defecography in fecal incontinence.

PubMed

Dobben, Annette C; Wiersma, Tjeerd G; Janssen, Lucas W M; de Vos, Rien; Terra, Maaike P; Baeten, Cor G; Stoker, Jaap

2005-11-01

The primary aim of our study was to determine the interobserver agreement of defecography in diagnosing enterocele, anterior rectocele, intussusception, and anismus in fecal-incontinent patients. The subsidiary aim was to evaluate the influence of level of experience on interpreting defecography. Defecography was performed in 105 consecutive fecal-incontinent patients. Observers were classified by level of experience and their findings were compared with the findings of an expert radiologist. The quality of the expert radiologist's findings was evaluated by an intraobserver agreement procedure. Intraobserver agreement was good to very good except for anismus: incomplete evacuation after 30 sec (kappa, 0.55) and puborectalis impression (kappa, 0.54). Interobserver agreement for enterocele and rectocele was good (kappa, 0.66 for both) and for intussusception, fair (kappa, 0.29). Interobserver agreement for anismus: incomplete evacuation after 30 sec was moderate (kappa, 0.47), and for anismus: puborectalis impression was fair (kappa, 0.24). Agreement in grading of enterocele and rectocele was good (kappa, 0.64 and 0.72, respectively) and for intussusception, fair (kappa, 0.39). Agreement separated by experience level was very good for rectocele (kappa, 0.83) and grading of rectoceles (kappa, 0.83) and moderate for intussusception (kappa, 0.44) at the most experienced level. For enterocele and grading, experience level did not influence the reproducibility. Reproducibility for enterocele, anterior rectocele, and severity grading is good, but for intussusception is fair to moderate. For anismus, the diagnosis of incomplete evacuation after 30 sec is more reproducible than puborectalis impression. The level of experience seems to play a role in diagnosing anterior rectocele and its grading and in diagnosing intussusception.

Substituted polyacetylene separation membrane

DOEpatents

Pinnau, Ingo; Morisato, Atsushi

1998-01-13

A separation membrane useful for gas separation, particularly separation of C.sub.2+ hydrocarbons from natural gas. The invention encompasses the membrane itself, methods of making it and processes for using it. The membrane comprises a polymer having repeating units of a hydrocarbon-based, disubstituted polyacetylene, having the general formula: ##STR1## wherein R.sub.1 is chosen from the group consisting of C.sub.1 -C.sub.4 alkyl and phenyl, and wherein R.sub.2 is chosen from the group consisting of hydrogen and phenyl. In the most preferred embodiment, the membrane comprises poly(4-methyl-2-pentyne) ›PMP!. The membrane exhibits good chemical resistance and has super-glassy properties with regard to separating certain large, condensable permeant species from smaller, less-condensable permeant species. The membranes may also be useful in other fluid separations.

Commentary: Malpractice Reform in Policy Perspective

PubMed Central

Bovbjerg, Randall R

2007-01-01

Enacted caps on malpractice awards and proposed early offer reform address the sometimes excessive verdicts of conventional liability and its very high overhead costs. However, such reforms greatly benefit medical defendants while doing too little for claimants or patients in general. Caps and early offer only affect current claims; far broader reforms are therefore needed to improve the woeful performance of liability as a general promoter of patient safety and injury compensation. Broad reforms, however desirable, seldom surmount high political and practical hurdles. A good, more evenhanded start would seek to make claims resolution faster, more accurate, more predictable, and less expensive, while separately promoting medical quality and safety as well as greater transparency for law, medicine, and insurance. PMID:17517117

Fabrication of polymeric nano-batteries array using anodic aluminum oxide templates.

PubMed

Zhao, Qiang; Cui, Xiaoli; Chen, Ling; Liu, Ling; Sun, Zhenkun; Jiang, Zhiyu

2009-02-01

Rechargeable nano-batteries were fabricated in the array pores of anodic aluminum oxide (AAO) template, combining template method and electrochemical method. The battery consisted of electropolymerized PPy electrode, porous TiO2 separator, and chemically polymerized PAn electrode was fabricated in the array pores of two-step anodizing aluminum oxide (AAO) membrane, based on three-step assembling method. It performs typical electrochemical battery behavior with good charge-discharge ability, and presents a capacity of 25 nAs. AFM results show the hexagonal array of nano-batteries' top side. The nano-battery may be a promising device for the development of Micro-Electro-Mechanical Systems (MEMS), and Nano-Electro-Mechanical Systems (NEMS).

Study of Low Reynolds Number Effects on the Losses in Low-Pressure Turbine Blade Rows

NASA Technical Reports Server (NTRS)

Ashpis, David E.; Dorney, Daniel J.

1998-01-01

Experimental data from jet-engine tests have indicated that unsteady blade row interactions and separation can have a significant impact on the efficiency of low-pressure turbine stages. Measured turbine efficiencies at takeoff can be as much as two points higher than those at cruise conditions. Several recent studies have revealed that Reynolds number effects may contribute to the lower efficiencies at cruise conditions. In the current study numerical experiments have been performed to study the models available for low Reynolds number flows, and to quantify the Reynolds number dependence of low-pressure turbine cascades and stages. The predicted aerodynamic results exhibit good agreement with design data.

Low bit rate coding of Earth science images

NASA Technical Reports Server (NTRS)

Kossentini, Faouzi; Chung, Wilson C.; Smith, Mark J. T.

1993-01-01

In this paper, the authors discuss compression based on some new ideas in vector quantization and their incorporation in a sub-band coding framework. Several variations are considered, which collectively address many of the individual compression needs within the earth science community. The approach taken in this work is based on some recent advances in the area of variable rate residual vector quantization (RVQ). This new RVQ method is considered separately and in conjunction with sub-band image decomposition. Very good results are achieved in coding a variety of earth science images. The last section of the paper provides some comparisons that illustrate the improvement in performance attributable to this approach relative the the JPEG coding standard.

Hybrid Structure Multichannel All-Fiber Current Sensor.

PubMed

Jiang, Junzhen; Zhang, Hao; He, Youwu; Qiu, Yishen

2017-08-02

We have experimentally developed a hybrid-structure multi-channel all-fiber current sensor with ordinary silica fiber using fiber loop architecture. According to the rationale of time division multiplexing, the sensor combines parallel and serial structures. The purpose of the hybrid-structure multi-channel all-fiber current sensor is to get more information from the different measured points simultaneously. In addition, the hybrid-structure fiber current sensor exhibited a good linear response for each channel. A three-channel experiment was performed in the study and showed that the system could detect different current positions. Each channel could individually detect the current and needed a separate calibration system. Furthermore, the three channels will not affect each other.

Optimal design of DC-based polarization beam splitter in lithium niobate on insulator

NASA Astrophysics Data System (ADS)

Gong, Zisu; Yin, Rui; Ji, Wei; Wang, Junbao; Wu, Chonghao; Li, Xiao; Zhang, Shicheng

2017-08-01

We propose a DC-based polarization beam splitter (PBS) in lithium niobate on insulator (LNOI). Utilizing the high birefringence property of Lithium Niobate (LiNbO3, LN), the device is achieved by simple structure in a short length. With the use of beam propagation method (BPM), the simulation results show that the device has a good performance for the separation of TE and TM polarizations with a high extinction ratio (about 35 dB). The simulated fabrication tolerance for the variation of the waveguide width is about 100 nm and the bandwidth is about 65 nm when the extinction ratio is higher than 10 dB.

Linear programming phase unwrapping for dual-wavelength digital holography.

PubMed

Wang, Zhaomin; Jiao, Jiannan; Qu, Weijuan; Yang, Fang; Li, Hongru; Tian, Ailing; Asundi, Anand

2017-01-20

A linear programming phase unwrapping method in dual-wavelength digital holography is proposed and verified experimentally. The proposed method uses the square of height difference as a convergence standard and theoretically gives the boundary condition in a searching process. A simulation was performed by unwrapping step structures at different levels of Gaussian noise. As a result, our method is capable of recovering the discontinuities accurately. It is robust and straightforward. In the experiment, a microelectromechanical systems sample and a cylindrical lens were measured separately. The testing results were in good agreement with true values. Moreover, the proposed method is applicable not only in digital holography but also in other dual-wavelength interferometric techniques.

Multi-views storage model and access methods of conversation history in converged IP messaging system

NASA Astrophysics Data System (ADS)

Lu, Meilian; Yang, Dong; Zhou, Xing

2013-03-01

Based on the analysis of the requirements of conversation history storage in CPM (Converged IP Messaging) system, a Multi-views storage model and access methods of conversation history are proposed. The storage model separates logical views from physical storage and divides the storage into system managed region and user managed region. It simultaneously supports conversation view, system pre-defined view and user-defined view of storage. The rationality and feasibility of multi-view presentation, the physical storage model and access methods are validated through the implemented prototype. It proves that, this proposal has good scalability, which will help to optimize the physical data storage structure and improve storage performance.

Electromagnetic perception and individual features of human beings.

PubMed

Lebedeva, N N; Kotrovskaya, T I

2001-01-01

An investigation was made of the individual reactions of human subjects exposed to electromagnetic fields. We performed the study on 86 volunteers separated into two groups. The first group was exposed to the electromagnetic field of infralow frequencies, whereas the second group was exposed to the electromagnetic field of extremely high frequencies. We found that the electromagnetic perception of human beings correlated with their individual features, such as EEG parameters, the critical frequency of flash merging, and the electric current sensitivity. Human subjects who had a high-quality perception of electromagnetic waves showed an optimal balance of cerebral processes, an excellent functional state of the central nervous system, and a good decision criterion.

A novel key-frame extraction approach for both video summary and video index.

PubMed

Lei, Shaoshuai; Xie, Gang; Yan, Gaowei

2014-01-01

Existing key-frame extraction methods are basically video summary oriented; yet the index task of key-frames is ignored. This paper presents a novel key-frame extraction approach which can be available for both video summary and video index. First a dynamic distance separability algorithm is advanced to divide a shot into subshots based on semantic structure, and then appropriate key-frames are extracted in each subshot by SVD decomposition. Finally, three evaluation indicators are proposed to evaluate the performance of the new approach. Experimental results show that the proposed approach achieves good semantic structure for semantics-based video index and meanwhile produces video summary consistent with human perception.

Integration of GaAs vertical-cavity surface emitting laser on Si by substrate removal

NASA Astrophysics Data System (ADS)

Yeh, Hsi-Jen J.; Smith, John S.

1994-03-01

The successful integration of strained quantum well InGaAs vertical-cavity surface-emitting lasers (VCSELs) on both Si and Cu substrates was described using a GaAs substrate removal technique. The GaAs VCSEL structure was metallized and bonded to the Si substrate after growth. The GaAs substrate was then removed by selective chemical wet etching. Finally, the bonded GaAs film metallized on the top (emitting) side and separate lasers were defined. This is the first time a VCSEL had been integrated on a Si substrate with its substrate removed. The performance enhancement of GaAs VCSELs bonded on good thermal conductors are demonstrated.

Production of MAG via enzymatic glycerolysis

NASA Astrophysics Data System (ADS)

Jamlus, Norul Naziraa Ahmad; Derawi, Darfizzi; Salimon, Jumat

2015-09-01

Enzymatic glycerolysis of a medium chain methyl ester, methyl laurate was performed using lipase Candida antarctica (Novozyme 435) for 6 hours at 55°C. The percentage of components mixture of product were determined by using gas chromatography technique. The enzymatic reaction was successfully produced monolaurin (45.9 %), dilaurin (47.1 %) and trilaurin (7.0 %) respectively. Thin layer chromatography (TLC) plate also showed a good separation of component spots. Fourier transformation infra-red (FTIR) spectrum showed the presence of ester carbonyl at wavenumber 1739.99 cm-1 and hydrogen bonded O-H at 3512.03 cm-1. The product is potentially to be used as emulsifier and additive in food industry, pharmaceutical, as well as antibacterial.

Thermal evaporation-induced anhydrous synthesis of Fe3O4-graphene composite with enhanced rate performance and cyclic stability for lithium ion batteries.

PubMed

Dong, Yucheng; Ma, Ruguang; Hu, Mingjun; Cheng, Hua; Yang, Qingdan; Li, Yang Yang; Zapien, Juan Antonio

2013-05-21

We present a high-yield and low cost thermal evaporation-induced anhydrous strategy to prepare hybrid materials of Fe3O4 nanoparticles and graphene as an advanced anode for high-performance lithium ion batteries. The ~10-20 nm Fe3O4 nanoparticles are densely anchored on conducting graphene sheets and act as spacers to keep the adjacent sheets separated. The Fe3O4-graphene composite displays a superior battery performance with high retained capacity of 868 mA h g(-1) up to 100 cycles at a current density of 200 mA g(-1), and 539 mA h g(-1) up to 200 cycles when cycling at 1000 mA g(-1), high Coulombic efficiency (above 99% after 200 cycles), good rate capability, and excellent cyclic stability. The simple approach offers a promising route to prepare anode materials for practical fabrication of lithium ion batteries.

Poly(methyloctylsiloxane) immobilized on silica as a sorbent for solid-phase extraction of some pesticides.

PubMed

Vigna, Camila R M; Morais, Lais S R; Collins, Carol H; Jardim, Isabel C S F

2006-05-12

A laboratory-made sorbent for solid-phase extraction (SPE) was obtained by thermal immobilization of poly(methyloctylsiloxane) (PMOS) onto silica. Cartridges packed with the new sorbent were used for the simultaneous determination of imazethapyr, nicosulfuron, diuron, linuron and chlorimuron-ethyl in water. These pesticides were separated and quantified using high-performance liquid chromatography with diode array detection (HPLC-DAD). The recoveries achieved with the laboratory-made PMOS cartridges were compared with those of some commercially available silica-based and polymer-based cartridges having C18, C8 and NH(2) pendant groups. Method validation using the laboratory-made sorbent was performed for the five pesticides at three fortifications levels (1x, 2x and 10x the limit of quantification of each pesticide). The laboratory-made PMOS cartridge has low cost preparation and showed good recoveries (72-111%) for all pesticides. Repeatability and intermediate precision were lower than 15%. Its performance was similar or even better, in some cases, than those of the commercial cartridges.

Investigating the associations between hydration and exercise performance: methodology and limitations.

PubMed

Maughan, Ronald J

2012-11-01

Loss of body water, if sufficiently severe, impairs most physiological functions, but the body water content fluctuates over the course of a normal day with no implications for physical or mental performance. The point at which an effect of dehydration becomes apparent has been the subject of much debate, in part, at least, because of the different tests that have been applied, differences in the methodologies used to induce dehydration and also because of differences in the fitness and other physiological characteristics of the subjects studied. The act of drinking itself and the conscious denial of access to water will also have implications for subjective responses to the exercise task. In many published studies, it is difficult to separate the effects of ingestion of water from those of carbohydrate, electrolytes, and other drink components. Nevertheless, there is good evidence that drinking appropriate amounts of water, especially cold water, can enhance exercise performance in many situations. © 2012 International Life Sciences Institute.

Uniformity of dc and rf performance of MBE-grown AlGaN/GaN HEMTS on HVPE-grown buffers

NASA Astrophysics Data System (ADS)

Gillespie, J. K.; Fitch, R. C.; Moser, N.; Jenkins, T.; Sewell, J.; Via, D.; Crespo, A.; Dabiran, A. M.; Chow, P. P.; Osinsky, A.; Mastro, M. A.; Tsvetkov, D.; Soukhoveev, V.; Usikov, A.; Dmitriev, V.; Luo, B.; Pearton, S. J.; Ren, F.

2003-10-01

AlGaN/GaN high electron mobility transistors (HEMTs) were grown by molecular beam epitaxy (MBE) on 2 in. diameter GaN buffer layers grown by hydride vapor epitaxy (HVPE) on sapphire substrates. HEMTs with 1 μm gate length displayed excellent dc and rf performance uniformity with up to 258 separate devices measured for each parameter. The drain-source saturation current was 561 mA with a standard deviation of 1.9% over the 2 in. diameter, with a corresponding transconductance of 118 ± 3.9 mS/mm. The threshold voltage was -5.3 ± 0.07 V. The rf performance uniformity was equally good, with an fT of 8.6 ± 0.8 GHz and fmax of 12.8 ± 2.5 GHz. The results show the excellent uniformity of the MBE technique for producing AlGaN/GaN HEMTs and also the ability of HVPE to provide high quality buffers at low cost.

Ternary Solar Cells Based on Two Small Molecule Donors with Same Conjugated Backbone: The Role of Good Miscibility and Hole Relay Process.

PubMed

Xiao, Liangang; Liang, Tianxiang; Gao, Ke; Lai, Tianqi; Chen, Xuebin; Liu, Feng; Russell, Thomas P; Huang, Fei; Peng, Xiaobin; Cao, Yong

2017-09-06

Ternary organic solar cells (OSCs) are very attractive for further enhancing the power conversion efficiencies (PCEs) of binary ones but still with a single active layer. However, improving the PCEs is still challenging because a ternary cell with one more component is more complicated on phase separation behavior. If the two donors or two acceptors have similar chemical structures, good miscibility can be expected to reduce the try-and-error work. Herein, we report ternary devices based on two small molecule donors with the same backbone but different substituents. Whereas both binary devices show PCEs about 9%, the PCE of the ternary cells is enhanced to 10.17% with improved fill factor and short-circuit current values and external quantum efficiencies almost in the whole absorption wavelength region from 440 to 850 nm. The same backbone enables the donors miscible at molecular level, and the donor with a higher HOMO level plays hole relay process to facilitate the charge transportation in the ternary devices. Since side-chain engineering has been well performed to tune the active materials' energy levels in OSCs, our results suggest that their ternary systems are promising for further improving the binary cells' performance although their absorptions are not complementary.

Optimization and comparison of simultaneous and separate acquisition protocols for dual isotope myocardial perfusion SPECT.

PubMed

Ghaly, Michael; Links, Jonathan M; Frey, Eric C

2015-07-07

Dual-isotope simultaneous-acquisition (DISA) rest-stress myocardial perfusion SPECT (MPS) protocols offer a number of advantages over separate acquisition. However, crosstalk contamination due to scatter in the patient and interactions in the collimator degrade image quality. Compensation can reduce the effects of crosstalk, but does not entirely eliminate image degradations. Optimizing acquisition parameters could further reduce the impact of crosstalk. In this paper we investigate the optimization of the rest Tl-201 energy window width and relative injected activities using the ideal observer (IO), a realistic digital phantom population and Monte Carlo (MC) simulated Tc-99m and Tl-201 projections as a means to improve image quality. We compared performance on a perfusion defect detection task for Tl-201 acquisition energy window widths varying from 4 to 40 keV centered at 72 keV for a camera with a 9% energy resolution. We also investigated 7 different relative injected activities, defined as the ratio of Tc-99m and Tl-201 activities, while keeping the total effective dose constant at 13.5 mSv. For each energy window and relative injected activity, we computed the IO test statistics using a Markov chain Monte Carlo (MCMC) method for an ensemble of 1,620 triplets of fixed and reversible defect-present, and defect-absent noisy images modeling realistic background variations. The volume under the 3-class receiver operating characteristic (ROC) surface (VUS) was estimated and served as the figure of merit. For simultaneous acquisition, the IO suggested that relative Tc-to-Tl injected activity ratios of 2.6-5 and acquisition energy window widths of 16-22% were optimal. For separate acquisition, we observed a broad range of optimal relative injected activities from 2.6 to 12.1 and acquisition energy window of widths 16-22%. A negative correlation between Tl-201 injected activity and the width of the Tl-201 energy window was observed in these ranges. The results also suggested that DISA methods could potentially provide image quality as good as that obtained with separate acquisition protocols. We compared observer performance for the optimized protocols and the current clinical protocol using separate acquisition. The current clinical protocols provided better performance at a cost of injecting the patient with approximately double the injected activity of Tc-99m and Tl-201, resulting in substantially increased radiation dose.

Evaluating the Upset Protrusion Joining (UPJ) Method to Join Magnesium Castings to Dissimilar Metals

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

Logan, Stephen

2016-02-24

This presentation discusses advantages and best practices for incorporating magnesium in automotive component applications to achieve substantial mass reduction, as well as some of the key challenges with respect to joining, coating, and galvanic corrosion, before providing an introduction and status update of the U.S. Department of Energy and Department of Defense jointly sponsored Upset Protrusion Joining (UPJ) process development and evaluation project. This update includes sharing performance results of a benchmark evaluation of the self-pierce riveting (SPR) process for joining dissimilar magnesium (Mg) to aluminum (Al) materials in four unique coating configurations before introducing the UPJ concept and comparingmore » performance results of the joints made with the UPJ process to those made with the SPR process. Key results presented include: The benchmark SPR process can produce good joints in the MgAM60B-Al 6013 joint configuration with minimal cracking in the Mg coupons if the rivet is inserted from the Mg side into the Al side; Numerous bare Mg to bare Al joints made with the SPR process separated after only 6-wks of accelerated corrosion testing due to fracture of the rivet as a result of hydrogen embrittlement; For the same joint configurations, UPJ demonstrated substantially higher pre-corrosion joint strengths and post-corrosion joint strengths, primarily because of the larger diameter protrusion compared to smaller SPR rivet diameter and reduced degradation due to accelerated corrosion exposure; As with the SPR process, numerous bare Mg to bare Al joints made with the UPJ process also separated after 6-wks of accelerated corrosion testing, but unlike the SPR experience, the UPJ joints experienced degradation of the boss and head because of galvanic corrosion of the Mg casting, not hydrogen embrittlement of the steel rivet; In the configuration where both the Mg and Al were pretreated with Alodine 5200 prior to joining and the complete assembly was powder-coated afterwards, the UPJ process showed substantial improvement in corrosion performance compared to SPR where many SPR joints had separated after only 6-wks of exposure, but none of the UPJ joints had separated even after 8-wis; and In the cases where the Al panel was coated prior to joining to the pretreated Mg coupons, neither the SPR or UPJ joints showed any joint separation or substantial joint performance degradation even after 12-wks of accelerated corrosion exposure.« less

Helping Young Children Cope with Separation: A Bibliotherapeutic Approach.

ERIC Educational Resources Information Center

Bernstein, Joanne E.

Adults who wish to help children come to terms with loss from death, divorce, and other separations have a good ally in books. While not a complete cure, bibliotherapy can help children cope with loss by engaging the emotions and freeing them for conscious and productive use. Numerous books have appeared for children to read, enjoy, and use in…

Determination of volatile compounds in cider apple juices using a covalently bonded ionic liquid coating as the stationary phase in gas chromatography.

PubMed

Pello-Palma, Jairo; González-Álvarez, Jaime; Gutiérrez-Álvarez, María Dolores; Dapena de la Fuente, Enrique; Mangas-Alonso, Juan José; Méndez-Sánchez, Daniel; Gotor-Fernández, Vicente; Arias-Abrodo, Pilar

2017-04-01

A chromatographic method for the separation of volatile compounds in Asturian cider apple juices has been developed. For this separation purpose, a monocationic imidazolium-based ionic liquid bearing a reactive terminal iodine atom was synthesized by a quaternization-anion exchange chemical sequence. Next, the gas chromatography (GC) stationary phase was prepared by covalently linking the imidazolium monolith to the reactive silanol groups of the inner capillary wall at 70 °C. This coated GC column exhibited good thermal stability (290 °C), as well as good efficiency (2000 plates/m) in the separation of volatile compounds from Asturian apple cider juices, and was characterized using the Abraham solvation parameter model. The intra-day and inter-day precision of the chromatographic method was evaluated, obtaining relative standard deviations from 3.7 to 12.9% and from 7.4 to 18.0%, respectively. Furthermore, recoveries from 82.5 to 122% were achieved. Graphical Abstract Covalent bonding of an ionic liquid to inner column wall led to a great improvement of the separation efficiencies of stationary phases in gas chromatography.

Identification and determination of the saikosaponins in Radix bupleuri by accelerated solvent extraction combined with rapid-resolution LC-MS.

PubMed

Yang, Yun-Yun; Tang, You-Zhi; Fan, Chun-Lin; Luo, Hui-Tai; Guo, Peng-Ran; Chen, Jian-Xin

2010-07-01

A method based on accelerated solvent extraction combined with rapid-resolution LC-MS for efficient extraction, rapid separation, online identification and accurate determination of the saikosaponins (SSs) in Radix bupleuri (RB) was developed. The RB samples were extracted by accelerated solvent extraction using 70% aqueous ethanol v/v as solvent, at a temperature of 120 degrees C and pressure of 100 bar, with 10 min of static extraction time and three extraction cycles. Rapid-resolution LC separation was performed by using a C(18) column at gradient elution of water (containing 0.5% formic acid) and acetonitrile, and the major constituents were well separated within 20 min. A TOF-MS and an IT-MS were used for online identification of the major constituents, and 27 SSs were identified or tentatively identified. Five major bioactive SSs (SSa, SSc, SSd, 6''-O-acetyl-SSa and 6''-O-acetyl-SSd) with obvious peak areas and good resolution were chosen as benchmark substances, and a triple quadrupole MS operating in multiple-reaction monitoring mode was used for their quantitative analysis. A total of 16 RB samples from different regions of China were analyzed. The results indicated that the method was rapid, efficient, accurate and suitable for use in the quality control of RB.

Feasibility of Rapid Multitracer PET Tumor Imaging

NASA Astrophysics Data System (ADS)

Kadrmas, D. J.; Rust, T. C.

2005-10-01

Positron emission tomography (PET) can characterize different aspects of tumor physiology using various tracers. PET scans are usually performed using only one tracer since there is no explicit signal for distinguishing multiple tracers. We tested the feasibility of rapidly imaging multiple PET tracers using dynamic imaging techniques, where the signals from each tracer are separated based upon differences in tracer half-life, kinetics, and distribution. Time-activity curve populations for FDG, acetate, ATSM, and PTSM were simulated using appropriate compartment models, and noisy dual-tracer curves were computed by shifting and adding the single-tracer curves. Single-tracer components were then estimated from dual-tracer data using two methods: principal component analysis (PCA)-based fits of single-tracer components to multitracer data, and parallel multitracer compartment models estimating single-tracer rate parameters from multitracer time-activity curves. The PCA analysis found that there is information content present for separating multitracer data, and that tracer separability depends upon tracer kinetics, injection order and timing. Multitracer compartment modeling recovered rate parameters for individual tracers with good accuracy but somewhat higher statistical uncertainty than single-tracer results when the injection delay was >10 min. These approaches to processing rapid multitracer PET data may potentially provide a new tool for characterizing multiple aspects of tumor physiology in vivo.

Proteomic identification of erythrocyte membrane protein deficiency in hereditary spherocytosis.

PubMed

Peker, Selen; Akar, Nejat; Demiralp, Duygu Ozel

2012-03-01

Hereditary spherocytosis (HS) is the most common congenital hemolytic anemia in Caucasians, with an estimated prevalence ranging from 1:2000 to 1:5000. The molecular defect in one of the erythrocytes (RBC) membrane proteins underlying HS like; spectrin-α, spectrin-β, ankyrin, band 3 and protein 4.2 that lead to membrane destabilization and vesiculation, may change the RBCs into denser and more rigid cells (spherocytes), which are removed by the spleen, leading to the development of hemolytic anemia. It is classified as mild, moderate and severe, according to the degree of the hemolytic anemia and the associated symptoms. Two-dimensional gel electrophoresis (2-DE) is potentially valuable method for studying heritable disorders as HS that involve membrane proteins. This separation technique of proteins based upon two biophysically unrelated parameters; molecular weight and charge, is a good option in clinical proteomics in terms of ability to separate complex mixtures, display post-translational modifications and changes after phosphorylation. In this study, we have used contemporary methods with some modifications for the solubilisation, separation and identification of erythrocyte membrane proteins in normal and in HS RBCs. Spectrin alpha and beta chain, ankyrin and band 3 proteins expression differences were found with PDQuest software 8.0.1. and peptide mass fingerprinting (PMF) analysis performed for identification of proteins in this study.

Carrier-separating demodulation of phase shifting self-mixing interferometry

NASA Astrophysics Data System (ADS)

Tao, Yufeng; Wang, Ming; Xia, Wei

2017-03-01

A carrier separating method associated with noise-elimination had been introduced into a sinusoidal phase-shifting self-mixing interferometer. The conventional sinusoidal phase shifting self-mixing interferometry was developed into a more competitive instrument with high computing efficiency and nanometer accuracy of λ / 100 in dynamical vibration measurement. The high slew rate electro-optic modulator induced a sinusoidal phase carrier with ultralow insertion loss in this paper. In order to extract phase-shift quickly and precisely, this paper employed the carrier-separating to directly generate quadrature signals without complicated frequency domain transforms. Moreover, most noises were evaluated and suppressed by a noise-elimination technology synthesizing empirical mode decomposition with wavelet transform. The overall laser system was described and inherent advantages such as high computational efficiency and decreased nonlinear errors of the established system were demonstrated. The experiment implemented on a high precision PZT (positioning accuracy was better than 1 nm) and compared with laser Doppler velocity meter. The good agreement of two instruments shown that the short-term resolution had improved from 10 nm to 1.5 nm in dynamic vibration measurement with reduced time expense. This was useful in precision measurement to improve the SMI with same sampling rate. The proposed signal processing was performed in pure time-domain requiring no preprocessing electronic circuits.

Rapid determination of piracetam in human plasma and cerebrospinal fluid by micellar electrokinetic chromatography with sample direct injection.

PubMed

Yeh, Hsin-Hua; Yang, Yuan-Han; Ko, Ju-Yun; Chen, Su-Hwei

2006-07-07

A simple micellar electrokinetic chromatography (MEKC) method with UV detection at 200 nm for analysis of piracetam in plasma and in cerebrospinal fluid (CSF) by direct injection without any sample pretreatment is described. The separation of piracetam from biological matrix was performed at 25 degrees C using a background electrolyte consisting of Tris buffer with sodium dodecyl sulfate (SDS) as the electrolyte solution. Several parameters affecting the separation of the drug from biological matrix were studied, including the pH and concentrations of the Tris buffer and SDS. Under optimal MEKC condition, good separation with high efficiency and short analyses time is achieved. Using imidazole as an internal standard (IS), the linear ranges of the method for the determination of piracetam in plasma and in CSF were all between 5 and 500 microg/mL; the detection limit of the drug in plasma and in CSF (signal-to-noise ratio=3; injection 0.5 psi, 5s) was 1.0 microg/mL. The applicability of the proposed method for determination of piracetam in plasma and CSF collected after intravenous administration of 3g piracetam every 6h and oral administration 1.2g every 6h in encephalopathy patients with aphasia was demonstrated.

An in situ polymerization approach for the synthesis of superhydrophobic and superoleophilic nanofibrous membranes for oil-water separation.

PubMed

Shang, Yanwei; Si, Yang; Raza, Aikifa; Yang, Liping; Mao, Xue; Ding, Bin; Yu, Jianyong

2012-12-21

Superhydrophobic and superoleophilic nanofibrous membranes exhibiting robust oil-water separation performance were prepared by a facile combination of electrospun cellulose acetate (CA) nanofibers and a novel in situ polymerized fluorinated polybenzoxazine (F-PBZ) functional layer that incorporated silica nanoparticles (SiO(2) NPs). By employing the F-PBZ/SiO(2) NPs modification, the pristine hydrophilic CA nanofibrous membranes were endowed with a superhydrophobicity with the water contact angle of 161° and a superoleophilicity with the oil contact angle of 3°. Surface morphological studies have indicated that the wettability of resultant membranes could be manipulated by tuning the surface composition as well as the hierarchical structures. The quantitative hierarchical roughness analysis using the N(2) adsorption method has confirmed the major contribution of SiO(2) NPs on enhancing the porous structure, and a detailed correlation between roughness and solid-liquid interface pinning is proposed. Furthermore, the as-prepared membranes exhibited fast and efficient separation for oil-water mixtures and excellent stability over a wide range of pH conditions, which would make them a good candidate in industrial oil-polluted water treatments and oil spill cleanup, and also provided a new insight into the design and development of functional nanofibrous membranes through F-PBZ modification.

Synergies in Astrometry: Predicting Navigational Error of Visual Binary Stars

NASA Astrophysics Data System (ADS)

Gessner Stewart, Susan

2015-08-01

Celestial navigation can employ a number of bright stars which are in binary systems. Often these are unresolved, appearing as a single, center-of-light object. A number of these systems are, however, in wide systems which could introduce a margin of error in the navigation solution if not handled properly. To illustrate the importance of good orbital solutions for binary systems - as well as good astrometry in general - the relationship between the center-of-light versus individual catalog position of celestial bodies and the error in terrestrial position derived via celestial navigation is demonstrated. From the list of navigational binary stars, fourteen such binary systems with at least 3.0 arcseconds apparent separation are explored. Maximum navigational error is estimated under the assumption that the bright star in the pair is observed at maximum separation, but the center-of-light is employed in the navigational solution. The relationships between navigational error and separation, orbital periods, and observers' latitude are discussed.

Performance evaluation of a non-woven lithium ion battery separator prepared through a paper-making process

NASA Astrophysics Data System (ADS)

Huang, Xiaosong

2014-06-01

Porous separator functions to electrically insulate the negative and positive electrodes yet communicate lithium ions between the two electrodes when infiltrated with a liquid electrolyte. The separator must fulfill numerous requirements (e.g. permeability, wettability, and thermal stability) in order to optimize the abuse tolerance and electrochemical performance of a battery. Non-woven mat separators have advantages such as high porosity and heat resistance. However, their applications in lithium ion batteries are very limited as their inadequate pore structures could cause accelerated battery performance degradation and even internal short. This work features the development of thermally stable non-woven composite separators using a low cost paper-making process. The composite separators offer significantly improved thermal dimensional stability and exhibit superior wettability by the liquid electrolyte compared to a conventional polypropylene separator. The open porous structures of the non-woven composite separators also resulted in high effective ionic conductivities. The electrochemical performance of the composite separators was tested in coin cells. Stable cycle performances and improved rate capabilities have been observed for the coin cells with these composite separators.

Validating a benchmarking tool for audit of early outcomes after operations for head and neck cancer.

PubMed

Tighe, D; Sassoon, I; McGurk, M

2017-04-01

INTRODUCTION In 2013 all UK surgical specialties, with the exception of head and neck surgery, published outcome data adjusted for case mix for indicator operations. This paper reports a pilot study to validate a previously published risk adjustment score on patients from separate UK cancer centres. METHODS A case note audit was performed of 1,075 patients undergoing 1,218 operations for head and neck squamous cell carcinoma under general anaesthesia in 4 surgical centres. A logistic regression equation predicting for all complications, previously validated internally at sites A-C, was tested on a fourth external validation sample (site D, 172 operations) using receiver operating characteristic curves, Hosmer-Lemeshow goodness of fit analysis and Brier scores. RESULTS Thirty-day complication rates varied widely (34-51%) between the centres. The predictive score allowed imperfect risk adjustment (area under the curve: 0.70), with Hosmer-Lemeshow analysis suggesting good calibration. The Brier score changed from 0.19 for sites A-C to 0.23 when site D was also included, suggesting poor accuracy overall. CONCLUSIONS Marked differences in operative risk and patient case mix captured by the risk adjustment score do not explain all the differences in observed outcomes. Further investigation with different methods is recommended to improve modelling of risk. Morbidity is common, and usually has a major impact on patient recovery, ward occupancy, hospital finances and patient perception of quality of care. We hope comparative audit will highlight good performance and challenge underperformance where it exists.

Validating a benchmarking tool for audit of early outcomes after operations for head and neck cancer

PubMed Central

Sassoon, I; McGurk, M

2017-01-01

INTRODUCTION In 2013 all UK surgical specialties, with the exception of head and neck surgery, published outcome data adjusted for case mix for indicator operations. This paper reports a pilot study to validate a previously published risk adjustment score on patients from separate UK cancer centres. METHODS A case note audit was performed of 1,075 patients undergoing 1,218 operations for head and neck squamous cell carcinoma under general anaesthesia in 4 surgical centres. A logistic regression equation predicting for all complications, previously validated internally at sites A–C, was tested on a fourth external validation sample (site D, 172 operations) using receiver operating characteristic curves, Hosmer–Lemeshow goodness of fit analysis and Brier scores. RESULTS Thirty-day complication rates varied widely (34–51%) between the centres. The predictive score allowed imperfect risk adjustment (area under the curve: 0.70), with Hosmer–Lemeshow analysis suggesting good calibration. The Brier score changed from 0.19 for sites A–C to 0.23 when site D was also included, suggesting poor accuracy overall. CONCLUSIONS Marked differences in operative risk and patient case mix captured by the risk adjustment score do not explain all the differences in observed outcomes. Further investigation with different methods is recommended to improve modelling of risk. Morbidity is common, and usually has a major impact on patient recovery, ward occupancy, hospital finances and patient perception of quality of care. We hope comparative audit will highlight good performance and challenge underperformance where it exists. PMID:27917662

Performance prediction of a ducted rocket combustor

NASA Astrophysics Data System (ADS)

Stowe, Robert

2001-07-01

The ducted rocket is a supersonic flight propulsion system that takes the exhaust from a solid fuel gas generator, mixes it with air, and burns it to produce thrust. To develop such systems, the use of numerical models based on Computational Fluid Dynamics (CFD) is increasingly popular, but their application to reacting flow requires specific attention and validation. Through a careful examination of the governing equations and experimental measurements, a CFD-based method was developed to predict the performance of a ducted rocket combustor. It uses an equilibrium-chemistry Probability Density Function (PDF) combustion model, with a gaseous and a separate stream of 75 nm diameter carbon spheres to represent the fuel. After extensive validation with water tunnel and direct-connect combustion experiments over a wide range of geometries and test conditions, this CFD-based method was able to predict, within a good degree of accuracy, the combustion efficiency of a ducted rocket combustor.

Hydrodynamic chromatography of polystyrene microparticles in micropillar array columns.

PubMed

Op de Beeck, Jeff; De Malsche, Wim; Vangelooven, Joris; Gardeniers, Han; Desmet, Gert

2010-09-24

We report on the possibility to perform HDC in micropillar array columns and the potential advantages of such a system. The HDC performance of a pillar array column with pillar diameter = 5 microm and an interpillar distance of 2.5 microm has been characterized using both a low MW tracer (FITC) and differently sized polystyrene bead samples (100, 200 and 500 nm). The reduced plate height curves that were obtained for the different investigated markers all overlapped very well, and attained a minimum value of about h(min)=0.3 (reduction based on the pillar diameter), corresponding to 1.6 microm in absolute value and giving good prospects for high efficiency separations. The obtained reduced retention time values were in fair agreement with that predicted by the Di Marzio and Guttman model for a flow between flat plates, using the minimal interpillar distance as characteristic interplate distance. Copyright 2010 Elsevier B.V. All rights reserved.

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

Scott, A.N.; Thomas, M.D.A.

An investigation of fly ash (FA) produced from various blends of coal and petroleum coke (pet coke) fired at Belledune Generating Station, New Brunswick, Canada, was conducted to establish its performance relative to FA derived from coal-only combustion and its compliance with CSA A3000. The FA samples were beneficiated by an electrostatic separation process to produce samples for testing with a range of loss-on-ignition (LOI) values. The results of these studies indicate that the combustion of pet coke results in very little inorganic residue (for example, typically less than 0.5% ash) and the main impact on FA resulting from themore » co-combustion of coal and up to 25% pet coke is an increase in the unburned carbon content and LOI values. The testing of FA after beneficiation indicates that FA produced from fuels with up to 25% pet coke performs as good as FA produced from the same coal without pet coke.« less

Computational study of ibuprofen removal from water by adsorption in realistic activated carbons.

PubMed

Bahamon, Daniel; Carro, Leticia; Guri, Sonia; Vega, Lourdes F

2017-07-15

Molecular simulations using the Grand Canonical Monte Carlo (GCMC) method have been performed in order to obtain physical insights on how the interaction between ibuprofen (IBP) and activated carbons (ACs) in aqueous mixtures affects IBP removal from water by ACs. A nanoporous carbon model based on units of polyaromatic molecules with different number of rings, defects and polar-oxygenated sites is described. Individual effects of factors such as porous features and chemical heterogeneities in the adsorbents are investigated and quantified. Results are in good agreement with experimental adsorption data, highlightening the ability of GCMC simulation to describe the macroscopic adsorption performance in drug removal applications, while also providing additional insights into the IBP/water adsorption mechanism. The simulation results allow finding the optimal type of activated carbon material for separating this pollutant in water treatment. Copyright © 2017 Elsevier Inc. All rights reserved.

Simultaneous Determination of Piperine, Capsaicin, and Dihydrocapsaicin in Korean Instant-Noodle (Ramyun) Soup Base Using High-Performance Liquid Chromatography with Ultraviolet Detection.

PubMed

Shim, You-Shin; Kim, Jong-Chan; Jeong, Seung-Weon

2016-01-01

A simultaneous analytical method for piperine, capsaicin, and dihydrocapsaicin in Korean instant-noodle soup base using HPLC was validated in terms of precision, accuracy, sensitivity, and linearity. The HPLC separation was performed on a reversed-phase C18 column (5 μm particle size, 4.6 mm id, 250 mm length) using a UV detector fixed at 280 nm. The LOD and LOQ of the HPLC analyses ranged from 0.25 to 1.03 mg/kg. The intraday and interday precisions of the individual piperine, capsaicin, and dihydrocapsaicin were <10.55%, and the recovery values ranged from 85.43 to 94.68%. The calibration curves exhibited good linearity (r(2) = 0.999) within the tested ranges. These results suggest that the analytical method in this study can be used to classify Korean instant noodles based on their levels of spiciness.

[Simultaneous determination of six synthetic sweeteners in food by high performance liquid chromatography-tandem mass spectrometry].

PubMed

Liu, Xiaoxi; Ding, Li; Liu, Jinxia; Zhang, Ying; Huang, Zhiqiang; Wang, Libing; Chen, Bo

2010-11-01

A simple and sensitive method for the determination of six synthetic sweeteners (sodium cyclamate, saccharin sodium, acesulfame-K, aspartame, alitame and neotame) in food was developed. The synthetic sweeteners were extracted by methanol-water (1 : 1, v/v). The extract was separated on a C18 column using 0.1% (v/v) formic acid-5 mmol/L ammonium formate/acetonitrile as mobile phase, and then detected by high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) using multiple reaction monitoring (MRM) mode. The good linearities (r > 0.998) were achieved for all the analytes over the range of 20-500 microg/L. The recoveries obtained ranged from 81.3% to 106.0% at three spiked concentrations, with the relative standard deviations lower than 11%. The established method has been successfully applied to the determination of synthetic sweeteners in food.

‘If you are good, I get better’: the role of social hierarchy in perceptual decision-making

PubMed Central

Pannunzi, Mario; Ayneto, Alba; Deco, Gustavo; Sebastián-Gallés, Nuria

2014-01-01

So far, it was unclear if social hierarchy could influence sensory or perceptual cognitive processes. We evaluated the effects of social hierarchy on these processes using a basic visual perceptual decision task. We constructed a social hierarchy where participants performed the perceptual task separately with two covertly simulated players (superior, inferior). Participants were faster (better) when performing the discrimination task with the superior player. We studied the time course when social hierarchy was processed using event-related potentials and observed hierarchical effects even in early stages of sensory-perceptual processing, suggesting early top–down modulation by social hierarchy. Moreover, in a parallel analysis, we fitted a drift-diffusion model (DDM) to the results to evaluate the decision making process of this perceptual task in the context of a social hierarchy. Consistently, the DDM pointed to nondecision time (probably perceptual encoding) as the principal period influenced by social hierarchy. PMID:23946003

A simple, sensitive determination of ganciclovir in infant plasma by high-performance liquid chromatography with fluorescence detection.

PubMed

Yoshida, Terumitsu; Takahashi, Ryohei; Imai, Koichi; Uchida, Hiroshi; Arai, Yasutoshi; Oh-ishi, Tsutomu

2010-03-01

This study developed a simple and sensitive method using reversed-phase high-performance liquid chromatography (HPLC) for ganciclovir (GCV) plasma concentrations in cytomegalovirus infectious infants with hearing loss. The method involves a simple protein precipitation procedure that uses no solid-phase or liquid-liquid extraction. The HPLC separation was carried out on a Cadenza CD-C(18) column (3 microm, 4.6 mm x 150 mm) with phosphate buffer (pH 2.5, 25 mM) containing 1% methanol-acetonitrile mixture (4:3, v/v) as a mobile phase at a 0.7 mL/min flow rate. GCV was detected using a fluorescence detection (lambdaex/em: 265/380 nm). The quantification limit was 0.025 microg/mL for 100 microL of plasma sample at which good intra- and inter-assay coefficient of variation values (< 4.96%) and recoveries (94.9-96.5%) were established.

High performance sandwich structured Si thin film anodes with LiPON coating

NASA Astrophysics Data System (ADS)

Luo, Xinyi; Lang, Jialiang; Lv, Shasha; Li, Zhengcao

2018-06-01

The sandwich structured silicon thin film anodes with lithium phosphorus oxynitride (LiPON) coating are synthesized via the radio frequency magnetron sputtering method, whereas the thicknesses of both layers are in the nanometer range, i.e. between 50 and 200 nm. In this sandwich structure, the separator simultaneously functions as a flexible substrate, while the LiPON layer is regarded as a protective layer. This sandwich structure combines the advantages of flexible substrate, which can help silicon release the compressive stress, and the LiPON coating, which can provide a stable artificial solid-electrolyte interphase (SEI) film on the electrode. As a result, the silicon anodes are protected well, and the cells exhibit high reversible capacity, excellent cycling stability and good rate capability. All the results demonstrate that this sandwich structure can be a promising option for high performance Si thin film lithium ion batteries.

Determination of itopride hydrochloride by high-performance liquid chromatography with Ru(bpy)3(2+) electrogenerated chemiluminescence detection.

PubMed

Sun, Yonghua; Zhang, Zhujun; Xi, Zhijun; Shi, Zuolong; Tian, Wei

2009-08-26

In this work, a stable electrogenerated chemiluminescence (ECL) detector was developed. The detector was prepared by packing cation-exchanged resin particles in a glass tube, followed by inserting Pt wires (working electrode) in this tube and sealing. The leakage of Ru(bpy)(3)(2+) can be compensated by adding a small amount of Ru(bpy)(3)(2+) into solution phase. Coupled with high-performance liquid chromatography separation, the detector has been used for determination of itopride hydrochloride in human serum. Under the optimal conditions, the ECL intensity has a linear relationship with the concentration of itopride hydrochloride in the range of 1.0 x 10(-8) g mL(-1) to 1.0 x 10(-6) g mL(-1) and the detection limit was 3 x 10(-9) g mL(-1) (S/N=3). The as-prepared ECL detector displayed good sensitivity and stability.

High performance sandwich structured Si thin film anodes with LiPON coating

NASA Astrophysics Data System (ADS)

Luo, Xinyi; Lang, Jialiang; Lv, Shasha; Li, Zhengcao

2018-04-01

The sandwich structured silicon thin film anodes with lithium phosphorus oxynitride (LiPON) coating are synthesized via the radio frequency magnetron sputtering method, whereas the thicknesses of both layers are in the nanometer range, i.e. between 50 and 200 nm. In this sandwich structure, the separator simultaneously functions as a flexible substrate, while the LiPON layer is regarded as a protective layer. This sandwich structure combines the advantages of flexible substrate, which can help silicon release the compressive stress, and the LiPON coating, which can provide a stable artificial solidelectrolyte interphase (SEI) film on the electrode. As a result, the silicon anodes are protected well, and the cells exhibit high reversible capacity, excellent cycling stability and good rate capability. All the results demonstrate that this sandwich structure can be a promising option for high performance Si thin film lithium ion batteries.

Firefighter Safety Zone: The effect of terrain slope of separation distance

Treesearch

Bret Butler; Jason Forthofer

2010-01-01

Perhaps one of the most critical decisions made on wildland fires is the identification of suitable safety zones for firefighters during daily fire management operations. To be effective (timely, repeatable, and accurate), these decisions rely on good training and good judgement. The current safety zone guidelines used in the US (see fig. 1) and published in the...

Understanding Evidence-Based Information for the Early Childhood Field: Tips from RAND's Promising Practices Network

ERIC Educational Resources Information Center

Mattox, Teryn; Kilburn, M. Rebecca

2012-01-01

With the growing and diverse use of the term "evidence-based practice" it can be difficult for policymakers, funders, program officers, and other professionals to separate the good evidence from the flawed. Furthermore, once good evidence has been identified, it can be difficult to know how to use it. This article discusses key issues to consider…

Feather Vibration as a Stimulus for Sensing Incipient Separation in Falcon Diving Flight

DTIC Science & Technology

2016-07-07

Thus the bird in streamlined shape has still a good measure to control its attitude to be in the narrow win- dow of safe angle of incidence. This...still a good measure to control its attitude to be around 5deg angle of incidence. Note that this was concluded from wind-tunnel tests, literature and

Gas Separation Using Organic-Vapor-Resistent Membranes In Conjunctin With Organic-Vapor-Selective Membranes

DOEpatents

Baker, Richard W.; Pinnau, Ingo; He, Zhenjie; Da Costa, Andre R.; Daniels, Ramin; Amo, Karl D.; Wijmans, Johannes G.

2003-06-03

A process for treating a gas mixture containing at least an organic compound gas or vapor and a second gas, such as natural gas, refinery off-gas or air. The process uses two sequential membrane separation steps, one using membrane selective for the organic compound over the second gas, the other selective for the second gas over the organic vapor. The second-gas-selective membranes use a selective layer made from a polymer having repeating units of a fluorinated polymer, and demonstrate good resistance to plasticization by the organic components in the gas mixture under treatment, and good recovery after exposure to liquid aromatic hydrocarbons. The membrane steps can be combined in either order.

Safety Assessment of Two Hybrid Instrumentation Techniques in a Dental Student Endodontic Clinic: A Retrospective Study.

PubMed

Coelho, Marcelo Santos; Card, Steven John; Tawil, Peter Zahi

2017-03-01

The aim of this study was to retrospectively assess the safety potential of a hybrid technique combining nickel-titanium (NiTi) reciprocating and rotary instruments by third- and fourth-year dental students in the predoctoral endodontics clinic at one U.S. dental school. For the study, 3,194 root canal treatments performed by 317 dental students from 2012 through 2015 were evaluated for incidence of ledge creation and instrument separation. The hybrid reciprocating and rotary technique (RRT) consisted of a glide path creation with stainless steel hand files up to size 15/02, a crown down preparation with a NiTi reciprocating instrument, and an apical preparation with NiTi rotary instruments. The control was a traditional rotary and hand technique (RHT) that consisted of the same glide path procedure followed by a crown down preparation with NiTi rotary instruments and an apical preparation with NiTi hand instruments. The results showed that the RHT technique presented a rate of ledge creation of 1.4% per root and the RRT technique was 0.5% per root (p<0.05). Three stainless steel hand files separated: two in the RHT group and one in the RRT group. There was no separation of any NiTi file in any of the techniques. The use of the reciprocating and rotary technique for root canal instrumentation by these dental students provided good safety. This hybrid technique offered a low rate of ledge creation along with no NiTi instrument separation.

Determination of β-blockers in pharmaceutical and human urine by capillary electrophoresis with electrochemiluminescence detection and studies on the pharmacokinetics.

PubMed

Wang, Yuanchao; Wu, Qiong; Cheng, Meirong; Cai, Cheng

2011-04-15

A novel method for simultaneous determination of atenolol, metoprolol and esmolol was proposed by capillary electrophoresis (CE) separation and electrochemiluminescence (ECL) detection. Poly-β-cyclodextrin (Poly-β-CD) was used as an additive in the running buffer to improve the separation of three analytes. The conditions for CE separation, ECL detection and effect of Poly-β-CD were investigated in detail. The three β-blockers with very similar structures were well separated and detected under the optimum conditions. The linear ranges of the standard solution for atenolol and esmolol were 2.5-125 μmol/L with a detection limit (S/N=3) of 0.5 μmol/L, and for metoprolol was 0.5-25 μmol/L with a detection limit of 0.1 μmol/L. For three β-blockers from spiked aqueous and urine samples, the accuracy and precision including intraday and interday experiments were performed by calculating the recovery, the relative standard deviations of the ECL intensity and the migration time, respectively. The developed method was applied to the determination of metoprolol content in commercial pharmaceutical, and the analytical results are in good agreement with the nominal value with recoveries in the range of 98.7-105%. The proposed method was also applied to the monitoring of pharmacokinetics for metoprolol in human body. Crown Copyright © 2011. Published by Elsevier B.V. All rights reserved.

Preparation and evaluation of a hydrophilic interaction and cation-exchange chromatography stationary phase modified with 2-methacryloyloxyethyl phosphorylcholine.

PubMed

Xiong, Caifeng; Yuan, Jie; Wang, Zhiying; Wang, Siyao; Yuan, Chenchen; Wang, Lili

2018-04-20

In this work, 2-methacryloyloxyethyl phosphorylcholine (MPC) was used as a ligand to prepare a novel mixed-mode chromatography (MMC) stationary phase by the thiol-ene click reaction onto silica (MPC-silica). It was found that this MPC-silica showed the retention characteristics of hydrophilic interaction chromatography (HILIC) and weak cation exchange chromatography (WCX) under suitable mobile phase conditions. In detail, acidic and basic hydrophilic compounds and puerarin from pueraria were separated quickly with HILIC mode. Meanwhile, six standard proteins were allowed to reach baseline separation in WCX mode, and protein separation from egg white was also achieved with this mode. In addition, reduced/denatured lysozyme could be refolded with the MPC-silica column. In the meantime, the MPC-silica has been applied for refolding with simultaneous purification of recombinant human Delta-like1-RGD (rhDll1-RGD) expressed in Escherichia coli. The results show that the mass recovery and purity of rhDll1-RGD could reach 63.4% and 97% by one step, respectively. Furthermore, the reporter assay results demonstrated that refolded with simultaneously purified rhDll1-RGD could efficiently activate the signalling pathway in a dose-dependent manner. In general, this MPC-silica has good resolution and selectivity in the separation of polar compounds and protein samples in different high-performance liquid chromatography (HPLC) modes, and it successfully achieved refolding with simultaneous purification of denatured protein. Copyright © 2018 Elsevier B.V. All rights reserved.

Hydroquinone and Quinone-Grafted Porous Carbons for Highly Selective CO2 Capture from Flue Gases and Natural Gas Upgrading.

PubMed

Wang, Jun; Krishna, Rajamani; Yang, Jiangfeng; Deng, Shuguang

2015-08-04

Hydroquinone and quinone functional groups were grafted onto a hierarchical porous carbon framework via the Friedel-Crafts reaction to develop more efficient adsorbents for the selective capture and removal of carbon dioxide from flue gases and natural gas. The oxygen-doped porous carbons were characterized with scanning electron microscopy, transmission electron microscopy, X-ray powder diffraction, Fourier transform infrared spectroscopy, and Raman spectroscopy. CO2, CH4, and N2 adsorption isotherms were measured and correlated with the Langmuir model. An ideal adsorbed solution theory (IAST) selectivity for the CO2/N2 separation of 26.5 (298 K, 1 atm) was obtained on the hydroquinone-grafted carbon, which is 58.7% higher than that of the pristine porous carbon, and a CO2/CH4 selectivity value of 4.6 (298 K, 1 atm) was obtained on the quinone-grafted carbon (OAC-2), which represents a 28.4% improvement over the pristine porous carbon. The highest CO2 adsorption capacity on the oxygen-doped carbon adsorbents is 3.46 mmol g(-1) at 298 K and 1 atm. In addition, transient breakthrough simulations for CO2/CH4/N2 mixture separation were conducted to demonstrate the good separation performance of the oxygen-doped carbons in fixed bed adsorbers. Combining excellent adsorption separation properties and low heats of adsorption, the oxygen-doped carbons developed in this work appear to be very promising for flue gas treatment and natural gas upgrading.

A study of the laminar separation bubble on an airfoil at low Reynolds numbers using flow visualization techniques

NASA Technical Reports Server (NTRS)

Schmidt, Gordon S.; Mueller, Thomas J.

1987-01-01

The use of flow visualization to study separation bubbles is evaluated. The wind tunnel, two NACA 66(3)-018 airfoil models, and kerosene vapor, titanium tetrachloride, and surface flow visualizations techniques are described. The application of the three visualization techniques to the two airfoil models reveals that the smoke and vapor techniques provide data on the location of laminar separation and the onset of transition, and the surface method produces information about the location of turbulent boundary layer separation. The data obtained with the three flow visualization techniques are compared to pressure distribution data and good correlation is detected. It is noted that flow visualization is an effective technique for examining separation bubbles.

Dynamic neural networks based on-line identification and control of high performance motor drives

NASA Technical Reports Server (NTRS)

Rubaai, Ahmed; Kotaru, Raj

1995-01-01

In the automated and high-tech industries of the future, there wil be a need for high performance motor drives both in the low-power range and in the high-power range. To meet very straight demands of tracking and regulation in the two quadrants of operation, advanced control technologies are of a considerable interest and need to be developed. In response a dynamics learning control architecture is developed with simultaneous on-line identification and control. the feature of the proposed approach, to efficiently combine the dual task of system identification (learning) and adaptive control of nonlinear motor drives into a single operation is presented. This approach, therefore, not only adapts to uncertainties of the dynamic parameters of the motor drives but also learns about their inherent nonlinearities. In fact, most of the neural networks based adaptive control approaches in use have an identification phase entirely separate from the control phase. Because these approaches separate the identification and control modes, it is not possible to cope with dynamic changes in a controlled process. Extensive simulation studies have been conducted and good performance was observed. The robustness characteristics of neuro-controllers to perform efficiently in a noisy environment is also demonstrated. With this initial success, the principal investigator believes that the proposed approach with the suggested neural structure can be used successfully for the control of high performance motor drives. Two identification and control topologies based on the model reference adaptive control technique are used in this present analysis. No prior knowledge of load dynamics is assumed in either topology while the second topology also assumes no knowledge of the motor parameters.

Reproducibility of the six-minute walking test in chronic heart failure patients.

PubMed

Pinna, G D; Opasich, C; Mazza, A; Tangenti, A; Maestri, R; Sanarico, M

2000-11-30

The six-minute walking test (WT) is used in trials and clinical practice as an easy tool to evaluate the functional capacity of chronic heart failure (CHF) patients. As WT measurements are highly variable both between and within individuals, this study aims at assessing the contribution of the different sources of variation and estimating the reproducibility of the test. A statistical model describing WT measurements as a function of fixed and random effects is proposed and its parameters estimated. We considered 202 stable CHF patients who performed two baseline WTs separated by a 30 minute rest; 49 of them repeated the two tests 3 months later (follow-up control). They had no changes in therapy or major clinical events. Another 31 subjects performed two baseline tests separated by 24 hours. Collected data were analysed using a mixed model methodology. There was no significant difference between measurements taken 30 minutes and 24 hours apart (p = 0.99). A trend effect of 17 (1.4) m (mean (SE)) was consistently found between duplicate tests (p < 0.001). REML estimates of variance components were: 5189 (674) for subject differences in the error-free value; 1280 (304) for subject differences in spontaneous clinical evolution between baseline and follow-up control, and 266 (23) for the within-subject error. Hence, the standard error of measurement was 16.3 m, namely 4 per cent of the average WT performance (403 m) in this sample. The intraclass correlation coefficient was 0.96. We conclude that WT measurements are characterized by good intrasubject reproducibility and excellent reliability. When follow-up studies > or = 3 months are performed, unpredictable changes in individual walking performance due to spontaneous clinical evolution are to be expected. Their clinical significance, however, is not known. Copyright 2000 John Wiley & Sons, Ltd.

In situ polymerized superhydrophobic and superoleophilic nanofibrous membranes for gravity driven oil-water separation

NASA Astrophysics Data System (ADS)

Tang, Xiaomin; Si, Yang; Ge, Jianlong; Ding, Bin; Liu, Lifang; Zheng, Gang; Luo, Wenjing; Yu, Jianyong

2013-11-01

Creating an efficient, cost-effective method that can provide simple, practical and high-throughput separation of oil-water mixtures has proved extremely challenging. This work responds to these challenges by designing, fabricating and evaluating a novel fluorinated polybenzoxazine (F-PBZ) modified nanofibrous membrane optimized to achieve gravity driven oil-water separation. The membrane design is then realized by a facile combination of electrospun poly(m-phenylene isophthalamide) (PMIA) nanofibers and an in situ polymerized F-PBZ functional layer incorporating SiO2 nanoparticles (SiO2 NPs). By employing the F-PBZ/SiO2 NP modification, the pristine hydrophilic PMIA nanofibrous membranes are endowed with promising superhydrophobicity with a water contact angle of 161° and superoleophilicity with an oil contact angle of 0°. This new membrane shows high thermal stability (350 °C) and good repellency to hot water (80 °C), and achieves an excellent mechanical strength of 40.8 MPa. Furthermore, the as-prepared membranes exhibited fast and efficient separation of oil-water mixtures by a solely gravity driven process, which makes them good candidates for industrial oil-polluted water treatments and oil spill cleanup, and also provided new insights into the design and development of functional nanofibrous membranes through F-PBZ modification.Creating an efficient, cost-effective method that can provide simple, practical and high-throughput separation of oil-water mixtures has proved extremely challenging. This work responds to these challenges by designing, fabricating and evaluating a novel fluorinated polybenzoxazine (F-PBZ) modified nanofibrous membrane optimized to achieve gravity driven oil-water separation. The membrane design is then realized by a facile combination of electrospun poly(m-phenylene isophthalamide) (PMIA) nanofibers and an in situ polymerized F-PBZ functional layer incorporating SiO2 nanoparticles (SiO2 NPs). By employing the F-PBZ/SiO2 NP modification, the pristine hydrophilic PMIA nanofibrous membranes are endowed with promising superhydrophobicity with a water contact angle of 161° and superoleophilicity with an oil contact angle of 0°. This new membrane shows high thermal stability (350 °C) and good repellency to hot water (80 °C), and achieves an excellent mechanical strength of 40.8 MPa. Furthermore, the as-prepared membranes exhibited fast and efficient separation of oil-water mixtures by a solely gravity driven process, which makes them good candidates for industrial oil-polluted water treatments and oil spill cleanup, and also provided new insights into the design and development of functional nanofibrous membranes through F-PBZ modification. Electronic supplementary information (ESI) available: Detailed synthesis and structural confirmation of BAF-oda, OCA results, Raman spectrum and Movies S1 and S2. See DOI: 10.1039/c3nr03937d

Creating Drug Solubilization Compartments via Phase Separation in Multicomponent Buccal Patches Prepared by Direct Hot Melt Extrusion-Injection Molding.

PubMed

Alhijjaj, Muqdad; Bouman, Jacob; Wellner, Nikolaus; Belton, Peter; Qi, Sheng

2015-12-07

Creating in situ phase separation in solid dispersion based formulations to allow enhanced functionality of the dosage form, such as improving dissolution of poorly soluble model drug as well as being mucoadhesive, can significantly maximize the in vitro and in vivo performance of the dosage form. This formulation strategy can benefit a wide range of solid dosage forms for oral and alternative routes of delivery. This study using buccal patches as an example created separated phases in situ of the buccal patches by selecting the excipients with different miscibility with each other and the model drug. The quaternary dispersion based buccal patches containing PEG, PEO, Tween 80, and felodipine were prepared by direct hot melt extrusion-injection molding (HME-IM). The partial miscibility between Tween 80 and semicrystalline PEG-PEO led to the phase separation after extrusion. The Tween phases acted as drug solubilization compartments, and the PEG-PEO phase had the primary function of providing mucoadhesion and carrier controlled dissolution. As felodipine was preferably solubilized in the amorphous regions of PEG-PEO, the high crystallinity of PEG-PEO resulted in an overall low drug solubilizing capacity. Tween 80 was added to improve the solubilization capacity of the system as the model drug showed good solubility in Tween. Increasing the drug loading led to the supersaturation of drug in Tween compartments and crystalline drug dispersed in PEG-PEO phases. The spatial distribution of these phase-separated compartments was mapped using X-ray micro-CT, which revealed that the domain size and heterogeneity of the phase separation increased with increasing the drug loading. The outcome of this study provides new insights into the applicability of in situ formed phase separation as a formulation strategy for the delivery of poorly soluble drugs and demonstrated the basic principle of excipient selection for such technology.

High-throughput determination of faropenem in human plasma and urine by on-line solid-phase extraction coupled to high-performance liquid chromatography with UV detection and its application to the pharmacokinetic study.

PubMed

Xie, Rui; Wen, Jun; Wei, Hua; Fan, Guorong; Zhang, Dabing

2010-05-01

An automated system using on-line solid-phase extraction and HPLC with UV detection was developed for the determination of faropenem in human plasma and urine. Analytical process was performed isocratically with two reversed-phase columns connected by a switching valve. After simple pretreatment for plasma and urine with acetonitrile, a volume of 100microl upper layer of the plasma or urine samples was injected for on-line SPE column switching HPLC-UV analysis. The analytes were retained on the self-made trap column (Lichrospher C(18), 4.6mmx37mm, 25microm) with the loading solvent (20mM NaH(2)PO(4) adjusted pH 3.5) at flow rate of 2mlmin(-1), and most matrix materials were removed from the column to waste. After 0.5min washing, the valve was switched to another position so that the target analytes could be eluted from trap column to analytical column in the back-flush mode by the mobile phase (acetonitrile-20mM NaH(2)PO(4) adjusted pH 3.5, 16:84, v/v) at flow rate of 1.5mlmin(-1), and then separated on the analytical column (Ultimate XB-C(18), 4.6mmx50mm, 5microm).The complete cycle of the on-line SPE preconcentration purification and HPLC separation of the analytes was 5min. Calibration curves with good linearities (r=0.9994 for plasma sample and r=0.9988 for urine sample) were obtained in the range 0.02-5microgml(-1) in plasma and 0.05-10microg ml(-1) in urine for faropenem. The optimized method showed good performance in terms of specificity, linearity, detection and quantification limits, precision and accuracy. The method was successfully utilized to quantify faropenem in human plasma and urine to support the clinical pharmacokinetic studies. Copyright 2009 Elsevier B.V. All rights reserved.

T2-Weighted Dixon Turbo Spin Echo for Accelerated Simultaneous Grading of Whole-Body Skeletal Muscle Fat Infiltration and Edema in Patients With Neuromuscular Diseases.

PubMed

Schlaeger, Sarah; Klupp, Elisabeth; Weidlich, Dominik; Cervantes, Barbara; Foreman, Sarah C; Deschauer, Marcus; Schoser, Benedikt; Katemann, Christoph; Kooijman, Hendrik; Rummeny, Ernst J; Zimmer, Claus; Kirschke, Jan S; Karampinos, Dimitrios C

2018-04-02

The assessment of fatty infiltration and edema in the musculature of patients with neuromuscular diseases (NMDs) typically requires the separate performance of T1-weighted and fat-suppressed T2-weighted sequences. T2-weighted Dixon turbo spin echo (TSE) enables the generation of T2-weighted fat- and water-separated images, which can be used to assess both pathologies simultaneously. The present study examines the diagnostic performance of T2-weighted Dixon TSE compared with the standard sequences in 10 patients with NMDs and 10 healthy subjects. Whole-body magnetic resonance imaging was performed including T1-weighted Dixon fast field echo, T2-weighted short-tau inversion recovery, and T2-weighted Dixon TSE. Fatty infiltration and intramuscular edema were rated by 2 radiologists using visual semiquantitative rating scales. To assess intermethod and interrater agreement, weighted Cohen's κ coefficients were calculated. The ratings of fatty infiltration showed high intermethod and high interrater agreement (T1-weighted Dixon fast field echo vs T2-weighted Dixon TSE fat image). The evaluation of edematous changes showed high intermethod and good interrater agreement (T2-weighted short-tau inversion recovery vs T2-weighted Dixon TSE water image). T2-weighted Dixon TSE imaging is an alternative for accelerated simultaneous grading of whole-body skeletal muscle fat infiltration and edema in patients with NMDs.

Effects of Different Manufacturing Processes on TEMPO-Oxidized Carboxylated Cellulose Nanofiber Performance as Binder for Flexible Lithium-Ion Batteries.

PubMed

Lu, Huiran; Guccini, Valentina; Kim, Hyeyun; Salazar-Alvarez, German; Lindbergh, Göran; Cornell, Ann

2017-11-01

Carboxylated cellulose nanofibers (CNF) prepared using the TEMPO-route are good binders of electrode components in flexible lithium-ion batteries (LIB). However, the different parameters employed for the defibrillation of CNF such as charge density and degree of homogenization affect its properties when used as binder. This work presents a systematic study of CNF prepared with different surface charge densities and varying degrees of homogenization and their performance as binder for flexible LiFePO 4 electrodes. The results show that the CNF with high charge density had shorter fiber lengths compared with those of CNF with low charge density, as observed with atomic force microscopy. Also, CNF processed with a large number of passes in the homogenizer showed a better fiber dispersibility, as observed from rheological measurements. The electrodes fabricated with highly charged CNF exhibited the best mechanical and electrochemical properties. The CNF at the highest charge density (1550 μmol g -1 ) and lowest degree of homogenization (3 + 3 passes in the homogenizer) achieved the overall best performance, including a high Young's modulus of approximately 311 MPa and a good rate capability with a stable specific capacity of 116 mAh g -1 even up to 1 C. This work allows a better understanding of the influence of the processing parameters of CNF on their performance as binder for flexible electrodes. The results also contribute to the understanding of the optimal processing parameters of CNF to fabricate other materials, e.g., membranes or separators.

Prediction of fluctuating pressure environments associated with plume-induced separated flow fields

NASA Technical Reports Server (NTRS)

Plotkin, K. J.

1973-01-01

The separated flow environment induced by underexpanded rocket plumes during boost phase of rocket vehicles has been investigated. A simple semi-empirical model for predicting the extent of separation was developed. This model offers considerable computational economy as compared to other schemes reported in the literature, and has been shown to be in good agreement with limited flight data. The unsteady pressure field in plume-induced separated regions was investigated. It was found that fluctuations differed from those for a rigid flare only at low frequencies. The major difference between plume-induced separation and flare-induced separation was shown to be an increase in shock oscillation distance for the plume case. The prediction schemes were applied to PRR shuttle launch configuration. It was found that fluctuating pressures from plume-induced separation are not as severe as for other fluctuating environments at the critical flight condition of maximum dynamic pressure.

β-cyclodextrin-ionic liquid polymer based dynamically coating for simultaneous determination of tetracyclines by capillary electrophoresis.

PubMed

Zhou, Chunyan; Deng, Jingjing; Shi, Guoyue; Zhou, Tianshu

2017-04-01

Tetracyclines are a group of broad spectrum antibiotics widely used in animal husbandry to prevent and treat diseases. However, the improper use of tetracyclines may result in the presence of their residues in animal tissues or waste. Recently, great attention has been drawn towards the green solvents ionic liquids. Ionic liquids have been employed as a coating material to modify the electroosmotic flow in capillary electrophoresis. In this study, a functionalized ionic liquid, mono-6-deoxy-6-(3-methylimidazolium)-β-cyclodextrin tosylate, was synthesized and used for the simultaneous separation and quantification of tetracyclines by capillary electrophoresis. Good separation efficiency could be achieved due to the multiple functions of β-cyclodextrin derived ionic liquid, including the electrostatic interaction, the hydrogen bonding, and the cavity structure in β-cyclodextrin ionic liquid which can entrap the tetracyclines to form inclusion complex. After optimization, baseline separation achieved in 25 min with the running buffer consisted of 10 mmol/L, pH 7.2 phosphate buffer and 20 mmol/L β-cyclodextrin ionic liquid. The satisfied result demonstrated that the β-cyclodextrin ionic liquid is an ideal background electrolyte modifier in the separation of tetracyclines with high stability and good reproducibility. And it is an effective strategy to design and synthesize specific ILs as additive applied in separation. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Static test-stand performance of the YF-102 turbofan engine with several exhaust configurations for the Quiet Short-Haul Research Aircraft (QSRA)

NASA Technical Reports Server (NTRS)

Mcardle, J. G.; Homyak, L.; Moore, A. S.

1979-01-01

The performance of a YF-102 turbofan engine was measured in an outdoor test stand with a bellmouth inlet and seven exhaust-system configurations. The configurations consisted of three separate-flow systems of various fan and core nozzle sizes and four confluent-flow systems of various nozzle sizes and shapes. A computer program provided good estimates of the engine performance and of thrust at maximum rating for each exhaust configuration. The internal performance of two different-shaped core nozzles for confluent-flow configurations was determined to be satisfactory. Pressure and temperature surveys were made with a traversing probe in the exhaust-nozzle flow for some confluent-flow configurations. The survey data at the mixing plane, plus the measured flow rates, were used to calculate the static-pressure variation along the exhaust nozzle length. The computed pressures compared well with experimental wall static-pressure data. External-flow surveys were made, for some confluent-flow configurations, with a large fixed rake at various locations in the exhaust plume.

Gas separation membranes

DOEpatents

Schell, William J.

1979-01-01

A dry, fabric supported, polymeric gas separation membrane, such as cellulose acetate, is prepared by casting a solution of the polymer onto a shrinkable fabric preferably formed of synthetic polymers such as polyester or polyamide filaments before washing, stretching or calendering (so called griege goods). The supported membrane is then subjected to gelling, annealing, and drying by solvent exchange. During the processing steps, both the fabric support and the membrane shrink a preselected, controlled amount which prevents curling, wrinkling or cracking of the membrane in flat form or when spirally wound into a gas separation element.

Morphological evolution of nanocrystal metal-on-insulator films grown by pulsed laser deposition

NASA Astrophysics Data System (ADS)

Warrender, Jeffrey Michael

Pulsed laser deposition (PLD) film growth differs from conventional thermal deposition in two essential ways: the depositing species arrive in short bursts of 10--100mus, and with 10--100 eV of kinetic energy. This thesis presents a comprehensive study of the influence of these separate characteristics of the PLD flux on film growth, with the goal of understanding what mechanisms and processes govern PLD morphology evolution. A theoretical description of the early stages of pulsed, non-energetic growth is presented, with the principal results being a discussion of the dimensionless parameters that must be controlled to achieve data collapse for a variety of conditions; the identification of at least four different island size distribution shapes, which characterize the growth mode being observed; and a rate equation formalism for pulsed deposition that gives excellent agreement with results from kinetic Monte Carlo (KMC) simulations. The model system of metal-on-insulator film growth has been studied extensively for thermal deposition, and is known to exhibit a characteristic morphological progression beginning with isolated three-dimensional islands and ending with a percolating, continuous film that conducts electrically. Two separate experimental investigations are reported for PLD growth of this system. In the fast, the details of the PLD pulse are held constant and the pulse frequency is varied; this amounts to varying the time-averaged deposition flux. Non-energetic KMC simulations, which take into account only the pulsed nature of the flux, predicted that, for the case where surface diffusion is very fast compared to the pulse frequency and the deposition rate, percolation thickness would scale with pulse frequency with an exponent of -0.34. Experiments performed at 93°C and 135°C gave scaling exponents of -0.31 and -0.34 respectively, in good agreement with the KMC prediction. The experiments also showed good data collapse when maintaining a constant value B/f, where B is the coalescence "efficiency" and f is the pulse frequency. A separate experimental investigation was performed to compare PLD with thermal deposition under otherwise identical background and substrate conditions; this amounts to studying the effect of varying the average deposition flux. For this case, non-energetic simulations predict that PLD deposits, by virtue of having smaller and more densely spaced islands, would reach percolation with relatively less deposition. (Abstract shortened by UMI.)

Rapid, sensitive and simultaneous determination of fluorescence-labeled polyamines in human hair by high-pressure liquid chromatography coupled with electrospray-ionization time-of-flight mass spectrometry.

PubMed

Sugiura, Koichi; Min, Jun Zhe; Toyo'oka, Toshimasa; Inagaki, Shinsuke

2008-09-26

The rapid, sensitive and simultaneous determination of six polyamines, i.e., ornithine (ORN), 1,3-diaminopropane (DAP), putrescine (PUT), cadaverine (CAD), spermidine (SPD) and spermine (SPM), in human hairs was performed by ultra-performance liquid chromatography (UPLC) with fluorescence (FL) detection and electrospray-ionization time-of-flight mass spectrometry (ESI-TOF-MS). The primary (-NH(2)) and secondary (-NH) amines in the polyamine structures were first labeled with 4-(N,N-dimethylaminosulfonyl)-7-fluoro-2,1,3-benzoxadiazole (DBD-F) at 60 degrees C for 30 min in the mixture of 0.1M borax (pH 9.3) and acetonitrile (CH(3)CN). The resulting derivatives were perfectly separated using an ACQUITY UPLC BEH C(18) column (1.7 microm, 100 mm x 2.1mm i.d.) by a gradient elution with a mixture of water-acetonitrile containing 0.1% formic acid (HCOOH). The separated polyamine derivatives were sensitively detected with both FL and TOF-MS. The detection limits in FL and TOF-MS were 11-86 and 2-5 fmol, respectively. However, the determination of several polyamines by FL detection was interfered with by endogenous substances in the hair. Therefore, the simultaneous determination in hair was carried out by the combination of UPLC separation and the ESI-TOF-MS detection. The structures of the polyamines were identified from the protonated-molecular ions [M+H](+) obtained from the TOF-MS measurement. A good linearity was achieved from the calibration curves, that was obtained by plotting the peak area ratios of the analytes relative to the internal standard (IS), i.e., 1,6-diaminohexane (DAH), against the injected amounts of each polyamine (0.05-50 pmol, r(2)>0.999). The proposed method was applied to the determination in the hairs of healthy volunteers. The mean concentrations of ORN, DAP, PUT, CAD, SPD and SPM in 1mg of human hairs (n=20) were 1.46, 0.18, 1.18, 0.11, 1.97 and 0.98 pmol, respectively. Because the proposed method provides a good mass accuracy and the trace detection of the polyamines in hair, this analytical technique seems to be applicable for the determination of various biological compounds in hair.

Sociopolitical and economic elements to explain the environmental performance of countries.

PubMed

Almeida, Thiago Alexandre das Neves; García-Sánchez, Isabel-María

2017-01-01

The present research explains environmental performance using an ecological composite index as the dependent variable and focusing on two national dimensions: sociopolitical characteristics and economics. Environmental performance is measured using the Composite Index of Environmental Performance (CIEP) indicator proposed by García-Sánchez et al. (2015). The first model performs a factor analysis to aggregate the variables according to each analyzed dimension. In the second model, the estimation is run using only single variables. Both models are estimated using generalized least square estimation (GLS) using panel data from 152 countries and 6 years. The results show that sociopolitical factors and international trade have a positive effect on environmental performance. When the variables are separately analyzed, democracy and social policy have a positive effect on environmental performance while transport, infrastructure, consumption of goods, and tourism have a negative effect. Further observation is that the trade-off between importing and exporting countries overshadows the pollution caused by production. It was also observed that infrastructure has a negative coefficient for developing countries and positive for developed countries. The best performances are in the democratic and richer countries that are located in Europe, while the worst environmental performance is by the nondemocratic and the poorest countries, which are on the African continent.

The simple determination method for anthocyanidin aglycones in fruits using ultra-high-performance liquid chromatography.

PubMed

Shim, You-Shin; Yoon, Won-Jin; Kim, Dong-Man; Watanabe, Masaki; Park, Hyun-Jin; Jang, Hae Won; Lee, Jangho; Ha, Jaeho

2015-01-01

The simple determination method for anthocyanidin aglycones in fruits using ultra-high-performance liquid chromatography (UHPLC) coupled with the heating-block acidic hydrolysis method was validated through the precision, accuracy and linearity. The UHPLC separation was performed on a reversed-phase C18 column (particle size 2 μm, i.d. 2 mm, length 100 mm) with a photodiode-array detector. The limits of detection and quantification of the UHPLC analyses were 0.09 and 0.29 mg/kg for delphinidin, 0.08 and 0.24 mg/kg for cyanidin, 0.09 and 0.26 mg/kg for petunidin, 0.14 and 0.42 mg/kg for pelargonidin, 0.16 and 0.48 mg/kg for peonidin and 0.30 and 0.91 mg/kg for malvidin, respectively. The intra- and inter-day precisions of individual anthocyanidin aglycones were <10.3%. All calibration curves exhibited good linearity (r = 0.999) within the tested ranges. The total run time of UHPLC was 8 min. The simple preparation method with UHPLC detection in this study presented herein significantly improved the speed and the simplicity for preparation step of delphinidin, cyanidin, petunidin, pelargonidin, peonidin and malvidin in fruits. Especially, the UHPLC detection exhibited good resolution in spite of shorter run time about four times than conventional HPLC detection. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

An Investigation of Transonic Resonance in a Mach 2.2 Round Convergent-Divergent Nozzle

NASA Technical Reports Server (NTRS)

Dippold, Vance F., III; Zaman, Khairul B. M. Q.

2015-01-01

Hot-wire and acoustic measurements were taken for a round convergent nozzle and a round convergent-divergent (C-D) nozzle at a jet Mach number of 0.61. The C-D nozzle had a design Mach number of 2.2. Compared to the convergent nozzle jet flow, the Mach 2.2 nozzle jet flow produced excess broadband noise (EBBN). It also produced a transonic resonance tone at 1200 Herz. Computational simulations were performed for both nozzle flows. A steady Reynolds-Averaged Navier-Stokes simulation was performed for the convergent nozzle jet flow. For the Mach 2.2 nozzle flow, a steady RANS simulation, an unsteady RANS (URANS) simulation, and an unsteady Detached Eddy Simulation (DES) were performed. The RANS simulation of the convergent nozzle showed good agreement with the hot-wire velocity and turbulence measurements, though the decay of the potential core was over-predicted. The RANS simulation of the Mach 2.2 nozzle showed poor agreement with the experimental data, and more closely resembled an ideally-expanded jet. The URANS simulation also showed qualitative agreement with the hot-wire data, but predicted a transonic resonance at 1145 Herz. The DES showed good agreement with the hot-wire velocity and turbulence data. The DES also produced a transonic tone at 1135 Herz. The DES solution showed that the destabilization of the shock-induced separation region inside the nozzle produced increased levels of turbulence intensity. This is likely the source of the EBBN.

Rapid determination of thiamine, riboflavin, niacinamide, pantothenic acid, pyridoxine, folic acid and ascorbic acid in Vitamins with Minerals Tablets by high-performance liquid chromatography with diode array detector.

PubMed

Jin, Pengfei; Xia, Lufeng; Li, Zheng; Che, Ning; Zou, Ding; Hu, Xin

2012-11-01

A simple, isocratic, and stability-indicating high-performance liquid chromatography (HPLC) method has been developed for the rapid determination of thiamine (VB(1)), niacinamide (VB(3)), pyridoxine (VB(6)), ascorbic acid (VC), pantothenic acid (VB(5)), riboflavin (VB(2)) and folic acid (VB(9)) in Vitamins with Minerals Tablets (VMT). An Alltima C(18) column (250 mm × 4.6 mm i.d., 5 μm) was used for the separation at ambient temperature, with 50mM ammonium dihydrogen phosphate (adjusting with phosphoric acid to pH 3.0) and acetonitrile as the mobile phase at the flow rate of 0.5 ml min(-1). VB(1), VB(3), VB(6), VC and VB(5) were extracted with a solution containing 0.05% phosphoric acid (v/v) and 0.3% sodium thiosulfate (w/v), and were then simultaneously analyzed by using the mobile phase of phosphate buffer-acetonitrile (95:5, v/v), while VB(2) and VB(9) were extracted with a solution containing 0.5% ammonium hydroxide solution (v/v), and were then simultaneously analyzed by using the mobile phase of phosphate buffer-acetonitrile (85:15, v/v). The detection wavelengths were 275 nm for VB(1), VB(3), VB(6), VC, 210 nm for VB(5), and 282 nm for VB(2) and VB(9). The method showed good system suitability, sensitivity, linearity, specificity, precision, stability and accuracy. All the seven water-soluble vitamins were well separated from other ingredients and degradation products. Method comparison indicated good concordance between the developed method and the USP method. The developed method was reliable and convenient for the rapid determination of VB(1), VB(3), VB(6), VC, VB(5), VB(2) and VB(9) in VMT. Copyright © 2012 Elsevier B.V. All rights reserved.